Responding to sepsis
How quickly key receptors are activated on blood vessel cells can determine whether one survives or succumbs to sepsis.
Sepsis, a potentially life-threatening immune response to blood-borne infections, leads to loss of blood vessel function, resulting in shock and multiorgan failure. Athan Kuliopulos and colleagues looked to see if inhibition or activation of a receptor called PAR1 could limit the severity of sepsis. Mice injected with bacteria directly into the bloodstream developed sepsis and died; however, these mice were protected if given a PAR1 inhibitor within 4 hours.
The surprise came if PAR1 was inhibited at later times, as this failed to protect these mice; rather, activation of PAR1 at these later times ‘protected’ mice from toxic shock. The authors show this ‘late’ activation of PAR1 induces another PAR receptor to become activated. This establishes a protective effect by instructing cells lining the blood vessel to maintain tight junctions and averting the widespread edema and intravascular blood clotting that accompanies shock.
These findings might lead to successful therapies for patients with sepsis and other systemic inflammatory responses.
Author contact:
Athan Kuliopulos (Tufts-New England Medical Center, Boston, MA, USA)
Tel: +1 617 636 8482; E-mail: athan.kuliopulos@tufts.edu
Monday, October 29, 2007
Long live transplants!
A new strategy to improve transplant survival in diabetic patients. In some individuals, Type 1 diabetes can be treated by transplanting pancreatic islets, but long-term survival of the transplants has been difficult to achieve. Islet grafts are rejected by the immune system, and efforts to increase their survival are usually aimed at dampening immune T-cell function.
Because B cells—another type of immune cell—may also play a role in graft rejection, Ali Naji and colleagues tested the effect of depleting B cells in monkeys transplanted with islet allografts. The authors found that rituximab, a B-cell depleting antibody approved for the treatment of Non-Hodgkin’s Lymphoma and rheumatoid arthritis, in combination with T-cell depleting therapy could extend survival of the grafts in some animals.
Long-term graft survival also normalized blood sugar levels, suggesting that B-cell depletion should be studied further for its potential benefit to therapies aimed at improving survival of islet transplants used to treat Type 1 diabetes.
Author contact:
Ali Naji (University of Pennsylvania School of Medicine, Philadelphia, PA, USA)
Tel: +1 215 662 2066; E-mail: ali.naji@uphs.upenn.edu
A new strategy to improve transplant survival in diabetic patients. In some individuals, Type 1 diabetes can be treated by transplanting pancreatic islets, but long-term survival of the transplants has been difficult to achieve. Islet grafts are rejected by the immune system, and efforts to increase their survival are usually aimed at dampening immune T-cell function.
Because B cells—another type of immune cell—may also play a role in graft rejection, Ali Naji and colleagues tested the effect of depleting B cells in monkeys transplanted with islet allografts. The authors found that rituximab, a B-cell depleting antibody approved for the treatment of Non-Hodgkin’s Lymphoma and rheumatoid arthritis, in combination with T-cell depleting therapy could extend survival of the grafts in some animals.
Long-term graft survival also normalized blood sugar levels, suggesting that B-cell depletion should be studied further for its potential benefit to therapies aimed at improving survival of islet transplants used to treat Type 1 diabetes.
Author contact:
Ali Naji (University of Pennsylvania School of Medicine, Philadelphia, PA, USA)
Tel: +1 215 662 2066; E-mail: ali.naji@uphs.upenn.edu
Phosphorylation on demand
A new chemical biology tool that explores protein modifications is presented in a paper online.These results will provide the framework for determining the biological function of many important biochemical signals.
Proteins are frequently encoded with special amino acid tags to send them to different parts of the cell; alternatively, proteins can be modified with a variety of small chemical compounds that cause them to move within the cell.
Peter G. Schultz and colleagues now study this process in the case of the protein Pho4 by introducing an unusual amino acid to the protein chain inside the cell. This amino acid looks like serine – one of the amino acids that is used to make proteins – except it is blocked by a bulky group that can be removed with light. Once exposed, the serine can be phosphorylated, or modified by the addition of a phosphate group, by a normal cellular process. The authors discovered that, out of five important serines in the protein sequence, one has particular importance in controlling whether the protein is sent out of the nucleus or not. This technique offers a powerful new method for monitoring the function of phosphorylation.
Author contact:
Peter G. Schultz (The Scripps Research Institute, La Jolla, CA, USA)
Tel: +1 858 784 9300, Email: schultz@scripps.edu
A new chemical biology tool that explores protein modifications is presented in a paper online.These results will provide the framework for determining the biological function of many important biochemical signals.
Proteins are frequently encoded with special amino acid tags to send them to different parts of the cell; alternatively, proteins can be modified with a variety of small chemical compounds that cause them to move within the cell.
Peter G. Schultz and colleagues now study this process in the case of the protein Pho4 by introducing an unusual amino acid to the protein chain inside the cell. This amino acid looks like serine – one of the amino acids that is used to make proteins – except it is blocked by a bulky group that can be removed with light. Once exposed, the serine can be phosphorylated, or modified by the addition of a phosphate group, by a normal cellular process. The authors discovered that, out of five important serines in the protein sequence, one has particular importance in controlling whether the protein is sent out of the nucleus or not. This technique offers a powerful new method for monitoring the function of phosphorylation.
Author contact:
Peter G. Schultz (The Scripps Research Institute, La Jolla, CA, USA)
Tel: +1 858 784 9300, Email: schultz@scripps.edu
Imaging: Clear crystal vision
The combined power of two techniques that probe matter at the atomic scale provides information about the structure and chemical composition of a crystal at an unprecedented level of detail, say researchers.Characterizing microstructures is important in various fields of science and technology. Semiconductor devices, for example, consist of nanometre-sized components, and the performance of the devices depends on the atomic microstructure.
Koji Kimoto and co-workers combine two current microscopy methods — scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) — having solved a number of technical problems, such as maintaining sufficient stability during measurements. This achievement allows them to continuously scan over a crystal surface, while taking spectroscopy measurements at each point. This results in two-dimensional maps of the positions of atoms of three different elements in various layers at and below the surface.
CONTACT
Koji KIMOTO (National Institute for Materials Science, Ibraki, Japan)
Tel: +81 29 860 4402; E-mail: KIMOTO.Koji@nims.go.jp
The combined power of two techniques that probe matter at the atomic scale provides information about the structure and chemical composition of a crystal at an unprecedented level of detail, say researchers.Characterizing microstructures is important in various fields of science and technology. Semiconductor devices, for example, consist of nanometre-sized components, and the performance of the devices depends on the atomic microstructure.
Koji Kimoto and co-workers combine two current microscopy methods — scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) — having solved a number of technical problems, such as maintaining sufficient stability during measurements. This achievement allows them to continuously scan over a crystal surface, while taking spectroscopy measurements at each point. This results in two-dimensional maps of the positions of atoms of three different elements in various layers at and below the surface.
CONTACT
Koji KIMOTO (National Institute for Materials Science, Ibraki, Japan)
Tel: +81 29 860 4402; E-mail: KIMOTO.Koji@nims.go.jp
Assessing Accounting Cycle Skill Software
The AssessUrBook initiative opens up a new dimension in examination and assessment approaches for basic accounting.
Arfah Salleh
Accounting cycle skill is fundamental to the mastery of accounting. It is long established that one way to enhance this skill is for learners to continually practice akin to the learning of mathematics. And in order to gauge one’s performance, a feedback system from examiners is essential. Given the mass of data, assessing learners’ work accurately is very challenging to examiners especially in situation where the number of scripts is large.
Till today, assessment software in accounting education is uncommon, and even if available, is designed to deal with only objective answer-type questions. AssessUrBook paves the way forward for e-assessment both as formative and summative evaluation tool.
AssessUrBook revolutionises accounting education by offering a technology-based solution to mark
students’ work while providing valuable immediate performance feedback. More specifically, the software provides a question bank, flexible and easily maintained by individual instructor and with questions capable to be randomly generated during examination setting. It offers a comprehensive examination format covering all bookkeeping processes from journalizing to preparing financial statements. It also gives a user-friendly interface as medium for instructors to build their answer schemes and for students to key in answers.
AssessUrBook breakthrough features include providing instant / real-time feedback with:
• detailed, individualised performance evaluation by question for each examination candidate;
• overall performance report for each specific assessment exercise;
• reduction in examiners’ assessment marking time while increasing marking accuracy and standardization; and
• flexibility to accept different grading systems.
The software also incorporates access control features to ensure that user groups are able to perform only designated tasks.
The AssessUrBook initiative is an invention that opens up a new dimension in examination and assessment approaches for basic accounting. The feedback mechanism which is superior than traditional approach should contribute to students’ learning. Almost all of the usual marking time is shown to be saved using AssessUrBook with increased accuracy, while some possible unethical examination practices can be contained through individualised randomly generated questions.
Given that accounting cycle is fundamental to basic accounting, this software is suitable for use by many user groups and at all levels of education, formal and informal, face-to-face or remote. User to benefit from this software include not only accounting school teachers and students, but also those pursuing degree programs whether accounting on non-accounting and also professional courses. Examination bodies are also to benefit from AssessUrBook.
For more information, please contact
Dr Nayan Kanwal
Research Management Centre
Universiti Putra Malaysia
Email: ndeeps@admin.upm.edu.my
Tel: +603 8946 6192
Fax: + 603 8942 6539
The AssessUrBook initiative opens up a new dimension in examination and assessment approaches for basic accounting.
Arfah Salleh
Accounting cycle skill is fundamental to the mastery of accounting. It is long established that one way to enhance this skill is for learners to continually practice akin to the learning of mathematics. And in order to gauge one’s performance, a feedback system from examiners is essential. Given the mass of data, assessing learners’ work accurately is very challenging to examiners especially in situation where the number of scripts is large.
Till today, assessment software in accounting education is uncommon, and even if available, is designed to deal with only objective answer-type questions. AssessUrBook paves the way forward for e-assessment both as formative and summative evaluation tool.
AssessUrBook revolutionises accounting education by offering a technology-based solution to mark
students’ work while providing valuable immediate performance feedback. More specifically, the software provides a question bank, flexible and easily maintained by individual instructor and with questions capable to be randomly generated during examination setting. It offers a comprehensive examination format covering all bookkeeping processes from journalizing to preparing financial statements. It also gives a user-friendly interface as medium for instructors to build their answer schemes and for students to key in answers.
AssessUrBook breakthrough features include providing instant / real-time feedback with:
• detailed, individualised performance evaluation by question for each examination candidate;
• overall performance report for each specific assessment exercise;
• reduction in examiners’ assessment marking time while increasing marking accuracy and standardization; and
• flexibility to accept different grading systems.
The software also incorporates access control features to ensure that user groups are able to perform only designated tasks.
The AssessUrBook initiative is an invention that opens up a new dimension in examination and assessment approaches for basic accounting. The feedback mechanism which is superior than traditional approach should contribute to students’ learning. Almost all of the usual marking time is shown to be saved using AssessUrBook with increased accuracy, while some possible unethical examination practices can be contained through individualised randomly generated questions.
Given that accounting cycle is fundamental to basic accounting, this software is suitable for use by many user groups and at all levels of education, formal and informal, face-to-face or remote. User to benefit from this software include not only accounting school teachers and students, but also those pursuing degree programs whether accounting on non-accounting and also professional courses. Examination bodies are also to benefit from AssessUrBook.
For more information, please contact
Dr Nayan Kanwal
Research Management Centre
Universiti Putra Malaysia
Email: ndeeps@admin.upm.edu.my
Tel: +603 8946 6192
Fax: + 603 8942 6539
Wednesday, October 24, 2007
New AIDS risk factor
More rapid HIV disease progression occurs in individuals who have a specific genetic risk factor, according to a new study.
A team of HIV researchers led by Sunil Ahuja studied a risk factor that significantly predicts HIV disease outcome. Individuals who have certain combinations of the two genes CCR5 and CCL3L1 are much more likely to have reduced immune responses and greater decline in numbers of CD4+ T immune cells, two hallmarks of progressive HIV disease.
The significance of the findings is two-fold. Previous work indicated that the influence of the two genes was much more limited that the new data indicate. These findings suggest a means to more effectively predict the course of HIV disease.
Author contact:
Sunil Ahuja (University of Texas Health Science Center, San Antonio, TX, USA)
Tel: +1 210 567 0233; E-mail: AHUJAS@uthscsa.edu
More rapid HIV disease progression occurs in individuals who have a specific genetic risk factor, according to a new study.
A team of HIV researchers led by Sunil Ahuja studied a risk factor that significantly predicts HIV disease outcome. Individuals who have certain combinations of the two genes CCR5 and CCL3L1 are much more likely to have reduced immune responses and greater decline in numbers of CD4+ T immune cells, two hallmarks of progressive HIV disease.
The significance of the findings is two-fold. Previous work indicated that the influence of the two genes was much more limited that the new data indicate. These findings suggest a means to more effectively predict the course of HIV disease.
Author contact:
Sunil Ahuja (University of Texas Health Science Center, San Antonio, TX, USA)
Tel: +1 210 567 0233; E-mail: AHUJAS@uthscsa.edu
Tuesday, October 23, 2007
Hospital Room Shook Up in First Seismic Experiment of Its Kind
Description
The world's first seismic testing apparatus for nonstructural components performed exactly as designed last Friday at the University at Buffalo and MCEER, providing engineers with the first realistic, experimental method of simulating and evaluating how earthquakes damage building equipment, contents and components.
In its initial public demonstration, the world's first seismic testing apparatus for nonstructural components performed exactly as designed last Friday at the University at Buffalo and MCEER, providing engineers with the first realistic, experimental method of simulating and evaluating how earthquakes damage building equipment, contents and components.
The National Science Foundation-funded Nonstructural Components Simulator (NCS) realistically simulated a fully equipped, upper-story hospital room experiencing two levels of seismic activity.
The demonstration took place in the Structural Engineering and Earthquake Simulation Laboratory (SEESL) in UB's School of Engineering and Applied Sciences for an audience of more than 100 earthquake engineers and industry representatives from across the U.S. who were attending the UB/MCEER symposium on "Seismic Regulations and Challenges for Protecting Building Equipment, Components and Operations."
"We are very pleased with the performance of the Nonstructural Components Simulator," said Gilberto Mosqueda, Ph.D., assistant professor of civil, structural and environmental engineering in the UB School of Engineering and Applied Sciences and lead designer and builder of the facility with Rodrigo Retamales, a doctoral student in the same department.
"These experiments clearly demonstrate new capabilities available at UB to test many types of nonstructural systems, whether they are attached to walls or connected between the top and bottom of a story in a building," he said. "We look forward to assisting our industry partners in testing and improving the performance of their products during earthquakes."
The NCS is the only system in the world capable of realistically simulating how the contents and distributed systems (i.e., water, sprinkler, medical gas piping) in important buildings, such as hospitals, react to strong ground shaking and amplified floor motions, said Mosqueda.
Mitigation and response to extreme events, whether natural events like earthquakes and hurricanes, or manmade like terrorist attacks, is a research strategic strength identified in the UB 2020 strategic plan being implemented by the university with the goal of rising among the ranks of the nation's public research universities.
Last week's tests were representative of a "design basis" earthquake, which has a 10 percent probability of occurring within the next 50 years and a "maximum considered earthquake," the largest earthquake shaking that a building could experience in its service life in a high-seismic zone in the U.S.
UB engineers and SEESL technicians constructed and equipped a 10-foot by 12-foot composite hospital room, outfitted with numerous systems typical of a critical-care facility, ranging from mechanical systems, such as sprinklers and medical gas lines, to ceiling-mounted surgical lamps, a suspended ceiling, infusion pumps and wall-mounted computer monitors.
"Ben," a crash dummy provided by Calspan, Inc., of Buffalo, was seated on top of a gurney that had been secured in its stationary position. Nonetheless, the gurney was tossed about like a toy in both tests, while "Ben" -- 180 pounds of dead weight -- hit the floor in the maximum event and was very severely tossed about in the design basis quake.
During the design basis earthquake test, UB engineers were surprised to see wall-mounted EKG monitors fall from their pedestals, since they were mounted according to current California standards. The maximum considered earthquake test caused a few ceiling tiles to fall.
"These failures highlight some potential vulnerabilities that should be further studied," said Andre Filiatrault, Ph.D., professor of civil, structural and environmental engineering at UB and director of SEESL.
While he cautioned that general conclusions cannot be drawn from these tests, which were conducted primarily to demonstrate the capabilities of the NCS, nonetheless, he said that these unexpected failures point to areas where engineers and manufacturers may want to focus their joint efforts in the future.
The NCS is coming online just as a consortium of universities, led by the University of Nevada at Reno, and including UB, has been awarded a five-year, $3.6 million National Science Foundation NEES Grand Challenge grant to investigate the performance of nonstructural systems during earthquakes.
For its portion of the research, UB's Department of Civil, Structural and Environmental Engineering will receive approximately $700,000.
In addition to complementary facilities at UNR, UB's Nonstructural Components Simulator and versatile, twin movable shake tables will provide a test bed for these research studies to conduct experiments to better understand and improve the seismic performance of nonstructural systems, particularly ceilings, piping and partition walls.
In addition to Filiatrault, Andre Reinhorn, Ph.D., Clifford C. Furnas Professor of Structural Engineering at UB and former SEESL director, and Andrew Whittaker, Ph.D., professor of civil, structural and environmental engineering will be leading the UB studies.
The testing platforms of the NCS were designed and constructed by UB engineers and SEESL staff; the hydraulic actuators that drive the system were manufactured by MTS Systems Corporation.
The University at Buffalo is a premier research-intensive public university, the largest and most comprehensive campus in the State University of New York. UB's more than 28,000 students pursue their academic interests through more than 300 undergraduate, graduate and professional degree programs. Founded in 1846, the University at Buffalo is a member of the Association of American Universities.(Newswise)
Researchers Develop, Patent Promising Oral Insulin for Treatment of Diabetesrds
Description
Syracuse University researchers have designed, tested and patented a new method of oral insulin delivery that can potentially help reduce daily insulin injections for millions of people with diabetes who require therapy for optimal glycemic control.
Syracuse University researchers have designed, tested and patented a new method of oral insulin delivery that can potentially help reduce daily insulin injections for millions of people with diabetes who require therapy for optimal glycemic control. The pharmaceutical journal ChemMedChem will publish in its December issue this research conducted by Robert Doyle, assistant professor of chemistry in SU’s College of Arts and Sciences; Timothy J. Fairchild, assistant professor of exercise science in SU’s School of Education; and Amanda Petrus and Anthony Vortherms, both chemistry graduate students in Doyle’s laboratory.
The non-invasive, basal delivery of insulin has been a major goal for the treatment of diabetes mellitus (DM), which affects more than 21 million individuals in the United States. Basal therapy describes a low, continuous dosage of insulin (commonly administered through a slow-acting insulin injection) that replaces the lack of insulin output by the pancreas in diabetics. This works together with bolus therapy, which is a dosage of insulin intended to replace a meal or to make a large glucose-level correction.
Up to this point, basal oral insulin deliveries have not been possible due to proteolytic degradation (digestion of proteins by cellular enzymes) and inefficient enteric uptake, meaning that free insulin delivered orally is never effectively delivered to the bloodstream because it is destroyed as it passes through the gastrointestinal tract (GIT), before it reaches its necessary receptors.
The team of SU researchers has now developed a method of oral insulin
delivery that eliminates the breakdown of insulin in the GIT, allowing for the transport of insulin to the bloodstream. This was accomplished by binding an insulin peptide to vitamin B-12, which acts as a carrier for the insulin and protects it as it is transported through the GIT. Because the insulin peptide is still intact as it enters the blood stream, it can be carried throughout the body as continuously as the B-12 vitamin is. This is a Trojan horse strategy, as the B-12 hides the insulin and carries it across the GIT's “walls.”
Mammals have an active transport mechanism in their GIT for the absorption and uptake of the relatively large vitamin B-12. Because of this, the length of this linkage is optimized so that the biological activity of both the B-12 and the biologically active substance (in this case, insulin) is maintained. At this point in the research, the SU team has focused on one insulin peptide carried by one B-12, which has a residence time in rats of about eight hours. However, they are now investigating whether more insulin can be attached to the B-12, which would provide a longer residence time—optimally 12 hours—so that potentially diabetics could take one insulin pill in the morning, and one at night for greater metabolic control throughout 24 hours.
This basal approach also helps prevent the continuous, unstabilized glucose uptake that is related to the development of metabolic-related complications in diabetics, including retinopathy and blindness, kidney failure, nerve damage, heart disease and stroke. Right now, the only options for this type of basal therapy are multiple injections of pre-prandial, short-acting insulin taken throughout the day. By providing long-lasting insulin analogues through this oral delivery, coupled with an inhalation bolus insulin therapy, diabetics in the future may rely on an entirely non-evasive delivery system for insulin using a basal/bolus regime.
Doyle believes that human investigations into the effectiveness of the team’s oral insulin delivery therapy may be a few years away, with new derivatives to be assembled and extensive further testing to be performed. “We have been interested in the oral delivery of insulin and also certain neuro-peptides, and have been exploring a variety of ways to achieve our goals,” says Doyle. “In the case of insulin, we had a hypothesis, we set about testing our hypothesis, and we were rewarded for the effort. Having things go your way doesn’t happen in science often enough, so when it does it’s very rewarding.”
Fairchild, in collaboration with the team, conducted the testing in diabetic rat models, focusing on the experimental protocol—dosage, methods of blood sampling and frequency—that should be used. “This is a very exciting time in diabetes-related research,” says Fairchild. “There are many research groups approaching potential treatment strategies for diabetes using a number of avenues, but the possibility of having an oral insulin medication has tremendous feasibility, particularly with children and in less-developed countries where sterile needles and adequate training—for injection site and frequency, as well as needle disposal—may not always be available.”
Petrus, a third-year graduate student studying inorganic chemistry in Doyle’s lab, served as the principal researcher. This research on oral insulin is her doctoral degree project and will be the bulk of her dissertation, which she will defend in two to three years. She carried out the synthesis of B-12/insulin and is currently working with new derivatives of it to try to gain improvement on its activity. “I am very honored to be contributing to a project with the potential to help people,” says Petrus. “It means a great deal to me that my dissertation will be addressing an issue that touches so many people. Diabetes runs in my family, and several of my friends are dealing with the early stages of the disease.”
“It is great to be a part of something that has the potential to help so many people,” says Vortherms, also a third-year chemistry graduate student at SU. “It is always exciting when you take something and you can do the unexpected with it. That kind of science turns heads and is what gets talked about years down the road.”
Description
Syracuse University researchers have designed, tested and patented a new method of oral insulin delivery that can potentially help reduce daily insulin injections for millions of people with diabetes who require therapy for optimal glycemic control.
Syracuse University researchers have designed, tested and patented a new method of oral insulin delivery that can potentially help reduce daily insulin injections for millions of people with diabetes who require therapy for optimal glycemic control. The pharmaceutical journal ChemMedChem will publish in its December issue this research conducted by Robert Doyle, assistant professor of chemistry in SU’s College of Arts and Sciences; Timothy J. Fairchild, assistant professor of exercise science in SU’s School of Education; and Amanda Petrus and Anthony Vortherms, both chemistry graduate students in Doyle’s laboratory.
The non-invasive, basal delivery of insulin has been a major goal for the treatment of diabetes mellitus (DM), which affects more than 21 million individuals in the United States. Basal therapy describes a low, continuous dosage of insulin (commonly administered through a slow-acting insulin injection) that replaces the lack of insulin output by the pancreas in diabetics. This works together with bolus therapy, which is a dosage of insulin intended to replace a meal or to make a large glucose-level correction.
Up to this point, basal oral insulin deliveries have not been possible due to proteolytic degradation (digestion of proteins by cellular enzymes) and inefficient enteric uptake, meaning that free insulin delivered orally is never effectively delivered to the bloodstream because it is destroyed as it passes through the gastrointestinal tract (GIT), before it reaches its necessary receptors.
The team of SU researchers has now developed a method of oral insulin
delivery that eliminates the breakdown of insulin in the GIT, allowing for the transport of insulin to the bloodstream. This was accomplished by binding an insulin peptide to vitamin B-12, which acts as a carrier for the insulin and protects it as it is transported through the GIT. Because the insulin peptide is still intact as it enters the blood stream, it can be carried throughout the body as continuously as the B-12 vitamin is. This is a Trojan horse strategy, as the B-12 hides the insulin and carries it across the GIT's “walls.”
Mammals have an active transport mechanism in their GIT for the absorption and uptake of the relatively large vitamin B-12. Because of this, the length of this linkage is optimized so that the biological activity of both the B-12 and the biologically active substance (in this case, insulin) is maintained. At this point in the research, the SU team has focused on one insulin peptide carried by one B-12, which has a residence time in rats of about eight hours. However, they are now investigating whether more insulin can be attached to the B-12, which would provide a longer residence time—optimally 12 hours—so that potentially diabetics could take one insulin pill in the morning, and one at night for greater metabolic control throughout 24 hours.
This basal approach also helps prevent the continuous, unstabilized glucose uptake that is related to the development of metabolic-related complications in diabetics, including retinopathy and blindness, kidney failure, nerve damage, heart disease and stroke. Right now, the only options for this type of basal therapy are multiple injections of pre-prandial, short-acting insulin taken throughout the day. By providing long-lasting insulin analogues through this oral delivery, coupled with an inhalation bolus insulin therapy, diabetics in the future may rely on an entirely non-evasive delivery system for insulin using a basal/bolus regime.
Doyle believes that human investigations into the effectiveness of the team’s oral insulin delivery therapy may be a few years away, with new derivatives to be assembled and extensive further testing to be performed. “We have been interested in the oral delivery of insulin and also certain neuro-peptides, and have been exploring a variety of ways to achieve our goals,” says Doyle. “In the case of insulin, we had a hypothesis, we set about testing our hypothesis, and we were rewarded for the effort. Having things go your way doesn’t happen in science often enough, so when it does it’s very rewarding.”
Fairchild, in collaboration with the team, conducted the testing in diabetic rat models, focusing on the experimental protocol—dosage, methods of blood sampling and frequency—that should be used. “This is a very exciting time in diabetes-related research,” says Fairchild. “There are many research groups approaching potential treatment strategies for diabetes using a number of avenues, but the possibility of having an oral insulin medication has tremendous feasibility, particularly with children and in less-developed countries where sterile needles and adequate training—for injection site and frequency, as well as needle disposal—may not always be available.”
Petrus, a third-year graduate student studying inorganic chemistry in Doyle’s lab, served as the principal researcher. This research on oral insulin is her doctoral degree project and will be the bulk of her dissertation, which she will defend in two to three years. She carried out the synthesis of B-12/insulin and is currently working with new derivatives of it to try to gain improvement on its activity. “I am very honored to be contributing to a project with the potential to help people,” says Petrus. “It means a great deal to me that my dissertation will be addressing an issue that touches so many people. Diabetes runs in my family, and several of my friends are dealing with the early stages of the disease.”
“It is great to be a part of something that has the potential to help so many people,” says Vortherms, also a third-year chemistry graduate student at SU. “It is always exciting when you take something and you can do the unexpected with it. That kind of science turns heads and is what gets talked about years down the road.”
Friday, October 19, 2007
Is There Second Life?
Brainwave with Image Offers Access to Second Life® Keio University Developed of Technology to Stroll Virtual World by Using Brainwaves
Assistant Prof. Junichi Ushiba of Faculty of Science and Technology succeeded to develop Brain-Computer Interface (BCI) technology that enable people stroll through the virtual world of Second Life® (*1) using their own imagination. This project is the first to apply the technology to an Internet virtual world.
1. About the Technology
A brain-computer interface, which allows people use their thoughts to control the movements of their Second Life® avatars has been developed. A user controls his/her avatar by wearing a headset which is equipped with electrodes that monitor activity in a field of the brain that controls the movement of limbs.
The system detects and processes brain activities which comes from the sensory-motor cortex, and automatically decodes users’ hand and foot imagery. When a user thinks about moving his own feet, the avatar walk forward. When a user thinks about moving his arms either right or left, that avatar turns that way.
2. Development in the Future
The technology that enables more complex movements and gesture in Second Life® will be developed in the future. It is intended to test the technology on real helping patients in paralysis patients to see how the technology is capable of the virtual world by collaboration with the medical team. We examine how active brain activity through stroll in Second Life® effects to the brain and the nerve, and investigate a possibility of application in the rehabilitation field.
The technology would enable people suffering from paralysis to communicate with others or conduct business in a virtual world.
3. Demonstration at the 8th Keio’s science and technology exhibition, KEIO TECHNO-MALL 2007
Please refer to the details of a moving image of the experiment: http://www.bme.bio.keio.ac.jp/eng/01news/
We plan to demonstrate of this experiment at KEIO TECHNO-MALL 2007 as follows:
Date: 5 December (wed) 2007, 10:00-17:00
Venue: Tokyo International Forum - B block 7th floor, Hall B
3-5-1 Marunouchi Chiyoda-ku Tokyo 100-0005, Japan
Website: http://www.kll.keio.ac.jp/ktm/en/
Inquiries: Ms. Nakajima or Ms. Mizuno, Office of Communications and Public Relations, Keio University
TEL: +81-3-5427-1541 FAX: +81-3-5441-7640
E-mail: m-koho@adst.keio.ac.jp http://www.keio.ac.jp/
Brainwave with Image Offers Access to Second Life® Keio University Developed of Technology to Stroll Virtual World by Using Brainwaves
Assistant Prof. Junichi Ushiba of Faculty of Science and Technology succeeded to develop Brain-Computer Interface (BCI) technology that enable people stroll through the virtual world of Second Life® (*1) using their own imagination. This project is the first to apply the technology to an Internet virtual world.
1. About the Technology
A brain-computer interface, which allows people use their thoughts to control the movements of their Second Life® avatars has been developed. A user controls his/her avatar by wearing a headset which is equipped with electrodes that monitor activity in a field of the brain that controls the movement of limbs.
The system detects and processes brain activities which comes from the sensory-motor cortex, and automatically decodes users’ hand and foot imagery. When a user thinks about moving his own feet, the avatar walk forward. When a user thinks about moving his arms either right or left, that avatar turns that way.
2. Development in the Future
The technology that enables more complex movements and gesture in Second Life® will be developed in the future. It is intended to test the technology on real helping patients in paralysis patients to see how the technology is capable of the virtual world by collaboration with the medical team. We examine how active brain activity through stroll in Second Life® effects to the brain and the nerve, and investigate a possibility of application in the rehabilitation field.
The technology would enable people suffering from paralysis to communicate with others or conduct business in a virtual world.
3. Demonstration at the 8th Keio’s science and technology exhibition, KEIO TECHNO-MALL 2007
Please refer to the details of a moving image of the experiment: http://www.bme.bio.keio.ac.jp/eng/01news/
We plan to demonstrate of this experiment at KEIO TECHNO-MALL 2007 as follows:
Date: 5 December (wed) 2007, 10:00-17:00
Venue: Tokyo International Forum - B block 7th floor, Hall B
3-5-1 Marunouchi Chiyoda-ku Tokyo 100-0005, Japan
Website: http://www.kll.keio.ac.jp/ktm/en/
Inquiries: Ms. Nakajima or Ms. Mizuno, Office of Communications and Public Relations, Keio University
TEL: +81-3-5427-1541 FAX: +81-3-5441-7640
E-mail: m-koho@adst.keio.ac.jp http://www.keio.ac.jp/
Fault Movement Continues Since 2004 Asian Tsunami
Description
Researchers say ongoing uplift following the 2004 Great Sumatra-Andaman Earthquake, which triggered massive tsunamis the day after Christmas, is caused by continuing slip on the quake fault.
“Parts of the Andaman Islands subsided, or rose, by up to a yard during the earthquake,” said Utah State University geophysicist Tony Lowry who, along with colleagues in Tennessee, Colorado and India, has monitored restless tectonic movements using GPS technology in the remote Indian Ocean islands, a focal point of the disaster. The findings were published October 13, 2007, in Geophysical Research Letters.
Scientists have observed dramatic post-earthquake movement following several large temblors, including the 2004 quake, though the latter boasts the largest movement recorded since GPS technology became available. GPS sites in the Andamans have recorded uplift ranging from six inches to more than a foot since the earthquake and even larger horizontal movements toward the southwest.
A hot topic of debate is what causes the movement.
In a study funded by the National Science Foundation, Lowry and associates from the University of Memphis’ Center for Earthquake Research and Information, the University of Colorado and India’s Society for Andaman and Nicobar Ecology collected GPS measurements at 11 sites in the Andaman Islands starting three weeks after the quake.
“Post-quake movement has generally been modeled as either deep rock flow in response to the stress change during an earthquake or as continued slip on the fault,” said Lowry, assistant professor in USU’s geology department. “Our research indicates that the Andaman post-earthquake movements resulted mostly from continuing silent slip on the fault, below the depth that slipped during the 2004 earthquake.”
The findings have further implications for the earthquake cycle on faults, including how stress accumulates in the time between quakes, he said.
“The data we’re collecting may eventually help us to better understand how and how often these sorts of really big earthquakes happen,” Lowry said.(Newswise)
Description
Researchers say ongoing uplift following the 2004 Great Sumatra-Andaman Earthquake, which triggered massive tsunamis the day after Christmas, is caused by continuing slip on the quake fault.
“Parts of the Andaman Islands subsided, or rose, by up to a yard during the earthquake,” said Utah State University geophysicist Tony Lowry who, along with colleagues in Tennessee, Colorado and India, has monitored restless tectonic movements using GPS technology in the remote Indian Ocean islands, a focal point of the disaster. The findings were published October 13, 2007, in Geophysical Research Letters.
Scientists have observed dramatic post-earthquake movement following several large temblors, including the 2004 quake, though the latter boasts the largest movement recorded since GPS technology became available. GPS sites in the Andamans have recorded uplift ranging from six inches to more than a foot since the earthquake and even larger horizontal movements toward the southwest.
A hot topic of debate is what causes the movement.
In a study funded by the National Science Foundation, Lowry and associates from the University of Memphis’ Center for Earthquake Research and Information, the University of Colorado and India’s Society for Andaman and Nicobar Ecology collected GPS measurements at 11 sites in the Andaman Islands starting three weeks after the quake.
“Post-quake movement has generally been modeled as either deep rock flow in response to the stress change during an earthquake or as continued slip on the fault,” said Lowry, assistant professor in USU’s geology department. “Our research indicates that the Andaman post-earthquake movements resulted mostly from continuing silent slip on the fault, below the depth that slipped during the 2004 earthquake.”
The findings have further implications for the earthquake cycle on faults, including how stress accumulates in the time between quakes, he said.
“The data we’re collecting may eventually help us to better understand how and how often these sorts of really big earthquakes happen,” Lowry said.(Newswise)
Wednesday, October 17, 2007
Blood May Help Us Think
Description- A MIT neuroscientist proposes that blood actively modulates how neurons process information, rather than just delivering “supplies” to neurons. The Hemo-Neural Hypothesis has clinical implications for diseases involving irregular vasculature like Alzheimer's, schizophrenia, multiple sclerosis and epilepsy. It also enriches the interpretation fMRI images from being just a marker of past brain activity to also being a predictor of future function.
MIT scientists propose that blood may help us think, in addition to its well-known role as the conveyor of fuel and oxygen to brain cells.
"We hypothesize that blood actively modulates how neurons process information," explains Christopher Moore, a principle investigator in the McGovern Institute for Brain Research at MIT, in an invited review in the Journal of Neurophysiology. "Many lines of evidence suggest that blood does something more interesting than just delivering supplies. If it does modulate how neurons relay signals, that changes how we think the brain works."
According to Moore's Hemo-Neural Hypothesis, blood is not just a physiological support system but actually helps control brain activity. Specifically, localized changes in blood flow affect the activity of nearby neurons, changing how they transmit signals to each other and hence regulating information flow throughout the brain. Ongoing studies in Moore's laboratory support this view, showing that blood flow does modulate individual neurons.
Moore's theory has implications for understanding brain diseases such as Alzheimer's, schizophrenia, multiple sclerosis and epilepsy. "Many neurological and psychiatric diseases have associated changes in the vasculature," says Moore, who is also an assistant professor in MIT's Department of Brain and Cognitive Sciences.
"Most people assume the symptoms of these diseases are a secondary consequence of damage to the neurons. But we propose that they may also be a causative factor in the disease process, and that insight suggests entirely new treatments." For example, in epilepsy people often have abnormal blood vessels in the brain region where the seizures occur, and the hypothesis suggests this abnormal flow may induce epileptic onset. If so, drugs that affect blood flow may provide an alternative to current therapies.
The hypothesis also has important implications for functional magnetic resonance imaging, or fMRI, a widely used brain scanning method that indicates local changes in blood flow. "Scientists looking at fMRI currently regard blood flow and volume changes as a secondary process that only provides read-out of neural activity," explains Rosa Cao, a graduate student in Moore's lab and co-author of the paper. "If blood flow shapes neural activity and behavior, then fMRI is actually imaging a key contributor to information processing."
Again, studies in Moore's lab support this interpretation. For example, his fMRI studies of the sensory homunculus - the brain's detailed map of body parts like fingers, toes, arms, and legs- show that when more blood flows to the area representing the fingertip, people more readily perceive a light tap on the finger. This suggests that blood affects the function of this brain region and that information about blood flow can predict future brain activity. This finding does not undermine prior studies, but adds another, richer layer to their interpretation and makes fMRI an even more useful tool than it already is.
How could blood flow affect brain activity? Blood contains diffusible factors that could leak out of vessels to affect neural activity, and changes to blood volume could affect the concentration of these factors. Also, neurons and support cells called glia may react to the mechanical forces of blood vessels expanding and contracting. In addition, blood influences the temperature of brain tissue, which affects neural activity.
To Moore's knowledge, the Hemo-Neural Hypothesis offers an entirely new way of looking at the brain. "No one ever includes blood flow in models of information processing in the brain," he asserts. One historical exception is the philosopher Aristotle, who thought the circulatory system was responsible for thoughts and emotions. Perhaps the ancient Greeks were on to something.
This work was funded by Thomas F. Peterson, the Mitsui Foundation and the McGovern Institute for Brain Research at MIT.
About the McGovern Institute for Brain Research at MIT
The McGovern Institute for Brain Research at MIT is led by a team of world-renowned neuroscientists committed to meeting two great challenges of modern science: understanding how the brain works and discovering new ways to prevent or treat brain disorders. The McGovern Institute was established in 2000 by Patrick J. McGovern and Lore Harp McGovern, who are committed to improving human welfare, communication and understanding through their support for neuroscience research. The director is Robert Desimone, formerly the head of intramural research at the National Institute of Mental Health. (newswise)
Saturday, October 13, 2007
World’s fastest supercomputer
RIKEN has taken on the challenge of developing the world’s fastest and most efficient supercomputer.
The computer is to boast a performance of 10 petaflops (that is, 1016 floating-point operations per second) in a general-purpose, compound configuration. RIKEN is to jointly develop the supercomputer with three major manufacturers, Fujitsu Corp., NEC Corp., and Hitachi Ltd, and if all goes according to plan, the new machine will be in operation by 2012.
The supercomputer will be a compound general-purpose configuration, and the project will incorporate the integrated development of both supercomputer and software. The system will feature both a scalar and a vector section, and it will incorporate cutting-edge technology, including 45 nm semiconductor processes and optical interconnection, to achieve compact size and relatively low electric-power consumption for a computer of this capability.
RIKEN will act as project headquarters for the academic–industrial collaboration. When complete, the supercomputer facility will be opened up for use by academic, industrial, and governmental bodies for everything from basic research to commercial applications. Its general-purpose nature will allow it to be used in a wide range of fields of scientific research, from life sciences to nanotechnology.
The project was instigated on orders from the Ministry of Education, Culture, Sports, Science and Technology, to develop the “world’s leading general-purpose supercomputer and the software to use it”. The Ministry also called for the establishment of the world’s most advanced supercomputing Center of Excellence, with the new supercomputer at its center. The Next-Generation Supercomputer R&D Center was established by RIKEN in January 2006.
RIKEN has taken on the challenge of developing the world’s fastest and most efficient supercomputer.
The computer is to boast a performance of 10 petaflops (that is, 1016 floating-point operations per second) in a general-purpose, compound configuration. RIKEN is to jointly develop the supercomputer with three major manufacturers, Fujitsu Corp., NEC Corp., and Hitachi Ltd, and if all goes according to plan, the new machine will be in operation by 2012.
The supercomputer will be a compound general-purpose configuration, and the project will incorporate the integrated development of both supercomputer and software. The system will feature both a scalar and a vector section, and it will incorporate cutting-edge technology, including 45 nm semiconductor processes and optical interconnection, to achieve compact size and relatively low electric-power consumption for a computer of this capability.
RIKEN will act as project headquarters for the academic–industrial collaboration. When complete, the supercomputer facility will be opened up for use by academic, industrial, and governmental bodies for everything from basic research to commercial applications. Its general-purpose nature will allow it to be used in a wide range of fields of scientific research, from life sciences to nanotechnology.
The project was instigated on orders from the Ministry of Education, Culture, Sports, Science and Technology, to develop the “world’s leading general-purpose supercomputer and the software to use it”. The Ministry also called for the establishment of the world’s most advanced supercomputing Center of Excellence, with the new supercomputer at its center. The Next-Generation Supercomputer R&D Center was established by RIKEN in January 2006.
Lanthanide as leading light for display technology
Innovative use of existing film technology may lead to a new type of thin-film display photo
A promising new way to make thin-film displays is being developed by a team of Japanese scientists led by Masaki Takata from the RIKEN SPring-8 Center, Harima.
Liquid crystal, thin-film displays are now commonplace in our daily lives; however, their manufacture is complex requiring a number of expensive and error-prone techniques to be used to produce each one. The result is a high-cost product. Consequently there is much interest in developing a new, lower-cost technique; a technique that Takata believes could be possible using their latest research findings.
The technique uses Langmuir–Blodgett films that are usually comprised of layers of organic molecules. The films are built-up one layer at a time until the desired number of layers is obtained. For this system, the team used two different layers. One layer contains the compound melem, which is capable of emitting light at specific wavelengths. The other layer contains a metal ion from the lanthanide group, praseodymium (Fig. 1).
Takata and colleagues explain in their latest paper published in Photochemical & Photobiological Sciences1 that in the films, the orientation and density of the molecules can be controlled. The exact positioning of these molecules then has a profound effect on their behavior. The emission spectra of the films were then studied in detail.
Two distinct emission bands were observed and the polarity of these bands was also different. The first band was seen at 370 nm and polarized through 0°; the second was seen at 410 nm and had polarized by 30°. This important finding means that if this film was used in optical fiber cables, two different streams of information could run down a single fiber simultaneously.
Interestingly, the results obtained from the thin-film are markedly different from what would be obtained from either a mixed solid or liquid of the two compounds. In the solid state, melem can bind in several ways with lanthanide metal ions through its nitrogen atoms forming a polymer-like complex. The resulting emission of praseodymium is then very weak and difficult to detect, which is the same as in a standard praseodymium complex with melem.
Even though scientists first started using Langmuir–Blodgett film techniques in the 1930s, Takata and a team member, Miki Hasegawa from Aoyama-Gakuin University in Tokyo, are confident that their team’s investigations into metal complexes and molecular interactions will uncover new optical properties. “Finally, we have found a new possibility by using [an] ‘old’ method with coordination chemistry,” they say.
Reference
1. Ishii, A., Habu, K., Kishi S., Ohtsu, H., Komatsu, T., Osaka, K., Kato, K., Kimura, S., Takata, M., Hasegawa, M. & Shigesato, Y. Novel emission properties of melem caused by the heavy metal effect of lanthanides(III) in a LB film. Photochemical & Photobiological Sciences 6, 804–809 (2007).
Innovative use of existing film technology may lead to a new type of thin-film display photo
A promising new way to make thin-film displays is being developed by a team of Japanese scientists led by Masaki Takata from the RIKEN SPring-8 Center, Harima.
Liquid crystal, thin-film displays are now commonplace in our daily lives; however, their manufacture is complex requiring a number of expensive and error-prone techniques to be used to produce each one. The result is a high-cost product. Consequently there is much interest in developing a new, lower-cost technique; a technique that Takata believes could be possible using their latest research findings.
The technique uses Langmuir–Blodgett films that are usually comprised of layers of organic molecules. The films are built-up one layer at a time until the desired number of layers is obtained. For this system, the team used two different layers. One layer contains the compound melem, which is capable of emitting light at specific wavelengths. The other layer contains a metal ion from the lanthanide group, praseodymium (Fig. 1).
Takata and colleagues explain in their latest paper published in Photochemical & Photobiological Sciences1 that in the films, the orientation and density of the molecules can be controlled. The exact positioning of these molecules then has a profound effect on their behavior. The emission spectra of the films were then studied in detail.
Two distinct emission bands were observed and the polarity of these bands was also different. The first band was seen at 370 nm and polarized through 0°; the second was seen at 410 nm and had polarized by 30°. This important finding means that if this film was used in optical fiber cables, two different streams of information could run down a single fiber simultaneously.
Interestingly, the results obtained from the thin-film are markedly different from what would be obtained from either a mixed solid or liquid of the two compounds. In the solid state, melem can bind in several ways with lanthanide metal ions through its nitrogen atoms forming a polymer-like complex. The resulting emission of praseodymium is then very weak and difficult to detect, which is the same as in a standard praseodymium complex with melem.
Even though scientists first started using Langmuir–Blodgett film techniques in the 1930s, Takata and a team member, Miki Hasegawa from Aoyama-Gakuin University in Tokyo, are confident that their team’s investigations into metal complexes and molecular interactions will uncover new optical properties. “Finally, we have found a new possibility by using [an] ‘old’ method with coordination chemistry,” they say.
Reference
1. Ishii, A., Habu, K., Kishi S., Ohtsu, H., Komatsu, T., Osaka, K., Kato, K., Kimura, S., Takata, M., Hasegawa, M. & Shigesato, Y. Novel emission properties of melem caused by the heavy metal effect of lanthanides(III) in a LB film. Photochemical & Photobiological Sciences 6, 804–809 (2007).
Looking forward at proton collisions
Asymmetry in neutrons produced by proton collisions makes a good detector for spin-polarized protons
An international team of researchers at the Relativistic Heavy Ion Collider (RHIC) of Brookhaven National Laboratory, in the US, has developed a new particle detector and used it to observe a large asymmetry in the distribution of neutrons produced during the collision of protons.
At RHIC, high-energy collisions of protons are studied to understand the fundamental physics governing subatomic particles like protons and neutrons. In these collisions, energy is converted to matter that generates a large number of particles as a result.
Of particular interest to particle physicists is the role of the quantum-mechanical property known as ‘spin’ in these collisions. Just as the needle of a compass points in a certain direction, so does the spin of protons and neutrons. The researchers have now studied collisions where the spins of the protons in the two colliding beams of the RHIC point in the same direction.
As the direction of the spin polarization is predetermined, any asymmetries in the direction at which the generated particles are scattered provide valuable clues on the influence of spin. “Such results are not only important to understand the fundamental physics of the collisions, but also to eventually use [these] asymmetries as a monitor for RHIC beam polarization,” explains Yuji Goto from the RIKEN team.
In their study, published in Physics Letters B1, the researchers have observed a large asymmetry in the number of neutrons that are produced in the left compared with the right side of the polarized proton beams. Their detector (Fig. 1), which is relatively compact for such complex tasks, consists of a calorimeter that measures the energy that is deposited in one of the beam directions. It also contains position and timing sensors for the necessary detailed analysis.
The asymmetry was found to be surprisingly large and Goto is convinced that “this is one of the most important results so far in the collision of spin-polarized protons at the RHIC”. Already, these findings provide important clues towards the fundamental processes leading to this asymmetry.
Moreover, the large asymmetry in neutron production can be used as a sensitive tool to measure the spin polarization and direction in the original proton beam. Indeed, the calorimeter has already been implemented at RHIC as a monitor of the polarization of the proton beams. The fundamental importance of these results aside, the detector developed by the researchers will play an important role in the other fundamental investigations performed at RHIC.
Reference
1. Fukao, Y., Togawa, M., Bazilevsky, A., Bland, L. C., Bogdanov, A., Bunce, G., Deshpande, A., En’yo, H., Fox, B.D. & Goto, Y. et al. Single transverse-spin asymmetry in very forward and very backward neutral particle production for polarized proton collisions at Image Symbol =200 GeV. Physics Letters B 650, 325–330 (2007).
Associated links
Asymmetry in neutrons produced by proton collisions makes a good detector for spin-polarized protons
An international team of researchers at the Relativistic Heavy Ion Collider (RHIC) of Brookhaven National Laboratory, in the US, has developed a new particle detector and used it to observe a large asymmetry in the distribution of neutrons produced during the collision of protons.
At RHIC, high-energy collisions of protons are studied to understand the fundamental physics governing subatomic particles like protons and neutrons. In these collisions, energy is converted to matter that generates a large number of particles as a result.
Of particular interest to particle physicists is the role of the quantum-mechanical property known as ‘spin’ in these collisions. Just as the needle of a compass points in a certain direction, so does the spin of protons and neutrons. The researchers have now studied collisions where the spins of the protons in the two colliding beams of the RHIC point in the same direction.
As the direction of the spin polarization is predetermined, any asymmetries in the direction at which the generated particles are scattered provide valuable clues on the influence of spin. “Such results are not only important to understand the fundamental physics of the collisions, but also to eventually use [these] asymmetries as a monitor for RHIC beam polarization,” explains Yuji Goto from the RIKEN team.
In their study, published in Physics Letters B1, the researchers have observed a large asymmetry in the number of neutrons that are produced in the left compared with the right side of the polarized proton beams. Their detector (Fig. 1), which is relatively compact for such complex tasks, consists of a calorimeter that measures the energy that is deposited in one of the beam directions. It also contains position and timing sensors for the necessary detailed analysis.
The asymmetry was found to be surprisingly large and Goto is convinced that “this is one of the most important results so far in the collision of spin-polarized protons at the RHIC”. Already, these findings provide important clues towards the fundamental processes leading to this asymmetry.
Moreover, the large asymmetry in neutron production can be used as a sensitive tool to measure the spin polarization and direction in the original proton beam. Indeed, the calorimeter has already been implemented at RHIC as a monitor of the polarization of the proton beams. The fundamental importance of these results aside, the detector developed by the researchers will play an important role in the other fundamental investigations performed at RHIC.
Reference
1. Fukao, Y., Togawa, M., Bazilevsky, A., Bland, L. C., Bogdanov, A., Bunce, G., Deshpande, A., En’yo, H., Fox, B.D. & Goto, Y. et al. Single transverse-spin asymmetry in very forward and very backward neutral particle production for polarized proton collisions at Image Symbol =200 GeV. Physics Letters B 650, 325–330 (2007).
Associated links
Don’t get too close
A new approach proves that the nuclear force is strongly repulsive at close distances
The force that holds atomic nuclei together is a complicated residual effect of the strong force between quarks and gluons—elementary particles that make up protons and neutrons. RIKEN researchers at the University of Tsukuba are explaining the nuclear force by extending quantum chromodynamics (QCD), the theory of the strong force (1).
The nuclear force involves the exchange of particles such as pions, first predicted by Nobel laureate Hideki Yukawa over 70 years ago. The force is thought to consist of three distinct regions (Fig. 1).
At separations greater than two femtometers (quadrillionths of a meter), the nuclear force falls off exponentially with distance and is mainly communicated by one-pion exchange. Closer in is a potential well that traps the nucleons at an average separation of about one femtometer—and where the exchange consists of multipions and heavy mesons. Closer still, the nucleons interact directly and the force is strongly repulsive.
The repulsive core explains scattering experiments, the stability of nuclei, and even supernova explosions. It is probably caused by the structures of quarks and gluons in the overlapping nucleons, but this remains an open question. The RIKEN researchers made use of lattice QCD—a theory restricting quarks and gluons to a discrete space-time lattice—to investigate the repulsive core in numerical simulations.
“Previous studies have tried to extract the nuclear force from the energy of two nucleons whose separation is kept fixed, but this is difficult because they move around,” says team-member Sinya Aoki. “In our study, we calculated the wave-function of two nucleon systems—which is very similar to experimentally measured quantities—and derived the potential from it.”
The potential obtained from the wave-function is plotted in Figure 1 as red dots. This result reproduces the nuclear potential observed in experiments, with repulsion at short distances and attraction at long distances. In particular, data at long distances are consistent with Yukawa's original one-pion exchange potential, represented by the blue line.
“At this moment, we can only say that QCD reproduces the qualitative behavior of the nuclear potential,” says Aoki, “however our study opens the possibility of studying the repulsive core from its first principle—the dynamics of quarks and gluons.”
In future, QCD could be extended to study interactions between hyperons. These three-quark particles (baryons) include the third type of quark, ‘strange quarks’, whereas nucleons only contain up and down quarks. Hyperons play important roles in neutron stars, but their interactions are not fully understood.
Reference
1. Ishii N., Aoki, S. & Hatsuda, T. Nuclear force from lattice QCD. Physical Review Letters 99, 022001 (2007).
A new approach proves that the nuclear force is strongly repulsive at close distances
The force that holds atomic nuclei together is a complicated residual effect of the strong force between quarks and gluons—elementary particles that make up protons and neutrons. RIKEN researchers at the University of Tsukuba are explaining the nuclear force by extending quantum chromodynamics (QCD), the theory of the strong force (1).
The nuclear force involves the exchange of particles such as pions, first predicted by Nobel laureate Hideki Yukawa over 70 years ago. The force is thought to consist of three distinct regions (Fig. 1).
At separations greater than two femtometers (quadrillionths of a meter), the nuclear force falls off exponentially with distance and is mainly communicated by one-pion exchange. Closer in is a potential well that traps the nucleons at an average separation of about one femtometer—and where the exchange consists of multipions and heavy mesons. Closer still, the nucleons interact directly and the force is strongly repulsive.
The repulsive core explains scattering experiments, the stability of nuclei, and even supernova explosions. It is probably caused by the structures of quarks and gluons in the overlapping nucleons, but this remains an open question. The RIKEN researchers made use of lattice QCD—a theory restricting quarks and gluons to a discrete space-time lattice—to investigate the repulsive core in numerical simulations.
“Previous studies have tried to extract the nuclear force from the energy of two nucleons whose separation is kept fixed, but this is difficult because they move around,” says team-member Sinya Aoki. “In our study, we calculated the wave-function of two nucleon systems—which is very similar to experimentally measured quantities—and derived the potential from it.”
The potential obtained from the wave-function is plotted in Figure 1 as red dots. This result reproduces the nuclear potential observed in experiments, with repulsion at short distances and attraction at long distances. In particular, data at long distances are consistent with Yukawa's original one-pion exchange potential, represented by the blue line.
“At this moment, we can only say that QCD reproduces the qualitative behavior of the nuclear potential,” says Aoki, “however our study opens the possibility of studying the repulsive core from its first principle—the dynamics of quarks and gluons.”
In future, QCD could be extended to study interactions between hyperons. These three-quark particles (baryons) include the third type of quark, ‘strange quarks’, whereas nucleons only contain up and down quarks. Hyperons play important roles in neutron stars, but their interactions are not fully understood.
Reference
1. Ishii N., Aoki, S. & Hatsuda, T. Nuclear force from lattice QCD. Physical Review Letters 99, 022001 (2007).
Thursday, October 11, 2007
Materials: Ferrotoroidic ordering found
A fourth form of ferroic order has been discovered, completing the family that includes ferromagnetism — the physics behind the humble fridge magnet — ferroelectricity and ferroelasticity. The discovery of ferrotoroidic ordering could lead to new types of data-storage devices.
In any ferroic material it is expected that domains are formed; these are regions that display different orientations of the magnetic order. To observe ferrotoroidicity, Manfred Fiebig and colleagues therefore set about to observe ferrotoroidic domains, and identified them in an antiferromagnetic material called LiCoPO4 using laser-optic techniques. Their find should result in a better understanding of the physics of multiferroics, currently of interest because their combined electronic and magnetic properties mean that the same material can perform more than one task.
CONTACT
Manfred Fiebig (Universitaet Bonn, Germany)
Tel: +49 228 73 2539; E-mail: fiebig@hiskp.uni-bonn.de
Karin Rabe (Rutgers University, Piscataway, NJ, USA) N&V author
Tel: +1 732 445 4186; E-mail: rabe@physics.rutgers.edu
A fourth form of ferroic order has been discovered, completing the family that includes ferromagnetism — the physics behind the humble fridge magnet — ferroelectricity and ferroelasticity. The discovery of ferrotoroidic ordering could lead to new types of data-storage devices.
In any ferroic material it is expected that domains are formed; these are regions that display different orientations of the magnetic order. To observe ferrotoroidicity, Manfred Fiebig and colleagues therefore set about to observe ferrotoroidic domains, and identified them in an antiferromagnetic material called LiCoPO4 using laser-optic techniques. Their find should result in a better understanding of the physics of multiferroics, currently of interest because their combined electronic and magnetic properties mean that the same material can perform more than one task.
CONTACT
Manfred Fiebig (Universitaet Bonn, Germany)
Tel: +49 228 73 2539; E-mail: fiebig@hiskp.uni-bonn.de
Karin Rabe (Rutgers University, Piscataway, NJ, USA) N&V author
Tel: +1 732 445 4186; E-mail: rabe@physics.rutgers.edu
Climate change: Getting steamy
A global-scale increase in surface humidity over the late twentieth century can be attributed mainly to human-induced global warming.
Specific humidity is a measure of how much water vapour there is in a given volume of air. The water vapour content of the atmosphere is an important component of the Earth’s climate system — affecting the distribution and maximum intensity of rainfall, the potential intensity of cyclones, and surface hydrology. Scientists have observed significant increases in specific humidity at the Earth’s surface over the last few decades, but it has been unclear whether these changes represent a natural or human influence on climate.
Nathan P. Gillett and colleagues combined a new data set of observations with a coupled climate model and found that a significant increase in global mean surface specific humidity over the late twentieth century was mainly due to anthropogenic warming. They conclude that this response to human-induced climate change may have important implications for extreme precipitation, tropical cyclones and human heat stress.
CONTACT
Nathan P. Gillett (University of East Anglia, Norwich, UK)
Tel: +44 1603 593 647; E-mail: n.gillett@uea.ac.uk
A global-scale increase in surface humidity over the late twentieth century can be attributed mainly to human-induced global warming.
Specific humidity is a measure of how much water vapour there is in a given volume of air. The water vapour content of the atmosphere is an important component of the Earth’s climate system — affecting the distribution and maximum intensity of rainfall, the potential intensity of cyclones, and surface hydrology. Scientists have observed significant increases in specific humidity at the Earth’s surface over the last few decades, but it has been unclear whether these changes represent a natural or human influence on climate.
Nathan P. Gillett and colleagues combined a new data set of observations with a coupled climate model and found that a significant increase in global mean surface specific humidity over the late twentieth century was mainly due to anthropogenic warming. They conclude that this response to human-induced climate change may have important implications for extreme precipitation, tropical cyclones and human heat stress.
CONTACT
Nathan P. Gillett (University of East Anglia, Norwich, UK)
Tel: +44 1603 593 647; E-mail: n.gillett@uea.ac.uk
Languages: Evolution and frequency of word use
Why do some words evolve rapidly through time whilst others stay the same, often with an identical meaning in many different languages? Why do some English verbs remain stubbornly irregular, to the frustration of language learners worldwide?
Some words, such as ‘bird’ or ‘tail’, are expressed by dozens of unrelated word forms in different languages, whereas others, such as the number ‘three’ or the word for ‘water’, use the same word forms or ‘cognates’ across the whole Indo-European language family. This indicates that some words evolve more quickly than others, but until now no general mechanism has been proposed to explain why.
Mark Pagel and colleagues used a statistical modelling technique to analyse four Indo-European languages: English, Spanish, Russian and Greek, and compared this to a database of 200 fundamental vocabulary meanings in 87 languages. They found that across all 200 meanings, commonly used words, such as numbers, evolve much more slowly, suggesting that the frequency with which specific words are used affects their rate of replacement over thousands of years.
In a separate paper, Martin Nowak and colleagues present a quantitative study to measure the rate at which verbs in English have become more regular with time, and find that frequency of use also affects this relationship. The authors compiled a list of 177 irregular verbs from Old English, and found that only 98 are still irregular today. They then calculated the frequency of occurrence for each verb, and discovered that the less a verb is used, the faster it takes a regular form.
CONTACT
Mark Pagel (University of Reading, UK) Author paper [1]
Tel: +44 118 931 8900; E-mail: m.pagel@reading.ac.uk
Martin Nowak (Harvard University, Cambridge, MA, USA) Author paper [2]
Tel: +1 617 496 4737; E-mail: martin_nowak@harvard.edu
Tecumseh Fitch (University of St Andrews, UK) N&V author
Tel: +44 1334 462 054; E-mail: wtsf@st-and.ac.uk
Why do some words evolve rapidly through time whilst others stay the same, often with an identical meaning in many different languages? Why do some English verbs remain stubbornly irregular, to the frustration of language learners worldwide?
Some words, such as ‘bird’ or ‘tail’, are expressed by dozens of unrelated word forms in different languages, whereas others, such as the number ‘three’ or the word for ‘water’, use the same word forms or ‘cognates’ across the whole Indo-European language family. This indicates that some words evolve more quickly than others, but until now no general mechanism has been proposed to explain why.
Mark Pagel and colleagues used a statistical modelling technique to analyse four Indo-European languages: English, Spanish, Russian and Greek, and compared this to a database of 200 fundamental vocabulary meanings in 87 languages. They found that across all 200 meanings, commonly used words, such as numbers, evolve much more slowly, suggesting that the frequency with which specific words are used affects their rate of replacement over thousands of years.
In a separate paper, Martin Nowak and colleagues present a quantitative study to measure the rate at which verbs in English have become more regular with time, and find that frequency of use also affects this relationship. The authors compiled a list of 177 irregular verbs from Old English, and found that only 98 are still irregular today. They then calculated the frequency of occurrence for each verb, and discovered that the less a verb is used, the faster it takes a regular form.
CONTACT
Mark Pagel (University of Reading, UK) Author paper [1]
Tel: +44 118 931 8900; E-mail: m.pagel@reading.ac.uk
Martin Nowak (Harvard University, Cambridge, MA, USA) Author paper [2]
Tel: +1 617 496 4737; E-mail: martin_nowak@harvard.edu
Tecumseh Fitch (University of St Andrews, UK) N&V author
Tel: +44 1334 462 054; E-mail: wtsf@st-and.ac.uk
Saturday, October 06, 2007
Sweet synthesis to aid understanding of bacteria
A new route to synthesize an antibiotic may also lead to new drugs
A team of Japanese scientists led by Shino Manabe from the RIKEN Discovery Research Institute, Wako, has synthesized an oligosaccharide with antibiotic activity.
Helicobacter pylori is a very common bacterium that infects nearly half the human population and can lead to diseases such as gastric ulcers, carcinoma and cancer. The infection takes hold in the lining of the stomach and can be treated using a combination of antibiotics; however resistance can be a problem and many people suffer allergic reactions to them. Therefore, the development of new, more effective antibiotics is crucial.
A few years ago, it was discovered that, although the bacterium prospers on the surface of the stomach lining, deeper down in the membrane its growth is suppressed. It was proposed that a glycoprotein, a protein with saccharide side chains, was responsible by effectively inhibiting the synthesis of a compound needed by the bacterium to form cell membranes (Fig. 1). Upon investigation this glycoprotein was shown to consist of an unusually branched hexasaccharide believed crucial for this behavior.
With existing methods to synthesize this molecule producing only small amounts of material, Manabe realized the importance of being able to make larger quantities to allow for more detailed studies. Therefore, her team set about designing and preparing an efficient strategy to produce the hexasaccharide as presented in a recent paper published in the Journal of Organic Chemistry1. The structure proved a challenge because a particular part of the saccharide needs to be arranged in an uncommon way where two adjoining groups are on the same side of the molecule instead of on opposite sides, known as a 1,2-cis linkage.
Overall the synthetic route developed by the team gave good yields in an efficient way allowing for greater quantities of material to be obtained. Manabe’s strategy has an additional benefit: the way in which the researchers have synthesized the compound means making derivatives will be straightforward. Following the success of this project, the team is now focusing on using their approach to synthesize various oligosaccharides and investigate their potential biological activity.
This planned study should provide the team with the opportunity to fully investigate and understand the inhibition mechanism and consequently develop suitable drugs. “It might be possible to develop a novel drug candidate that produces minimal side effects and is specific against Helicobacter pylori. The mechanism of growth inhibition is different from the currently used antibiotics,” explains Manabe.
Reference
1. Manabe, S., Ishii, K. & Ito, Y. Synthesis of a natural oligosaccharide antibiotic active against Helicobacter pylori. Journal of Organic Chemistry 72, 6107–6115 (2007).
A new route to synthesize an antibiotic may also lead to new drugs
A team of Japanese scientists led by Shino Manabe from the RIKEN Discovery Research Institute, Wako, has synthesized an oligosaccharide with antibiotic activity.
Helicobacter pylori is a very common bacterium that infects nearly half the human population and can lead to diseases such as gastric ulcers, carcinoma and cancer. The infection takes hold in the lining of the stomach and can be treated using a combination of antibiotics; however resistance can be a problem and many people suffer allergic reactions to them. Therefore, the development of new, more effective antibiotics is crucial.
A few years ago, it was discovered that, although the bacterium prospers on the surface of the stomach lining, deeper down in the membrane its growth is suppressed. It was proposed that a glycoprotein, a protein with saccharide side chains, was responsible by effectively inhibiting the synthesis of a compound needed by the bacterium to form cell membranes (Fig. 1). Upon investigation this glycoprotein was shown to consist of an unusually branched hexasaccharide believed crucial for this behavior.
With existing methods to synthesize this molecule producing only small amounts of material, Manabe realized the importance of being able to make larger quantities to allow for more detailed studies. Therefore, her team set about designing and preparing an efficient strategy to produce the hexasaccharide as presented in a recent paper published in the Journal of Organic Chemistry1. The structure proved a challenge because a particular part of the saccharide needs to be arranged in an uncommon way where two adjoining groups are on the same side of the molecule instead of on opposite sides, known as a 1,2-cis linkage.
Overall the synthetic route developed by the team gave good yields in an efficient way allowing for greater quantities of material to be obtained. Manabe’s strategy has an additional benefit: the way in which the researchers have synthesized the compound means making derivatives will be straightforward. Following the success of this project, the team is now focusing on using their approach to synthesize various oligosaccharides and investigate their potential biological activity.
This planned study should provide the team with the opportunity to fully investigate and understand the inhibition mechanism and consequently develop suitable drugs. “It might be possible to develop a novel drug candidate that produces minimal side effects and is specific against Helicobacter pylori. The mechanism of growth inhibition is different from the currently used antibiotics,” explains Manabe.
Reference
1. Manabe, S., Ishii, K. & Ito, Y. Synthesis of a natural oligosaccharide antibiotic active against Helicobacter pylori. Journal of Organic Chemistry 72, 6107–6115 (2007).
Just add barium
Squashed carbon balls show promising electronic properties
Theoretical calculations have shown that an exciting new material—made by squashing together latticework balls of carbon atoms—could be a superconductor.
Such superconductors are widely sought, since they carry electricity with no resistance and could be used to make extremely efficient energy transfer and storage systems.
Materials containing a cage-like structure of atoms, known as clathrates, have shown promise as superconductors. Scientists led by Shoji Yamanaka from Hiroshima University recently made a new clathrate1 based on buckminsterfullerene (C60)—a hollow molecule made of sixty carbon atoms arranged into a soccer ball shape. High temperatures and pressures were used to squeeze the balls together until they became interconnected cubes of carbon, dubbed clathrate-C60 (Fig. 1).
Toshiaki Iitaka of RIKEN’s Discovery Research Institute in Wako and colleagues from the University of Saskatchewan in Saskatoon, Canada, led by John Sak Tse, have now calculated the structural and electronic properties of this material, and report their results in the international edition of Angewandte Chemie2.
They found that pure clathrate-C60 is metallic, and suggest that it could be a superconductor. Recent experiments have confirmed that clathrate-C60 is weakly metallic, but found no superconductivity even at the low temperature of –269 ˚C: just four degrees above the coldest temperature possible, known as absolute zero. Colder temperatures even closer to absolute zero may be needed to uncover the predicted superconductivity, the team suggests.
The structure of clathrate-C60 allows individual metal atoms to sit either inside, or between, each of the carbon cages. The team looked at how adding barium—just the right size to fit in either space—would alter the material’s properties.
The team also found that in both cases, adding barium would release heat energy from the material, making the overall structure more stable. Although the compounds have not been made, this result means that the compounds should be achievable experimentally, the team says.
Further calculations revealed that if the barium atoms sit inside the carbon cages, they lose an electron—this does not change the overall structure by much, but it turns the material into a semiconductor. Conversely, adding barium atoms into the spaces between the carbon cages distorts the overall structure. The metal atoms also lose less charge, and the material remains metallic.
These changes in electronic properties suggest that clathrate-C60 “may potentially be an important electronic material for technology applications,” the scientists predict.
1. Yamanaka, S., Kubo, A., Inumaru, K., Komaguchi, K., Kini, N.S., Inoue, T. & Irifune, T. Electron conductive three-dimensional polymer of cuboidal C60. Physical Review Letters 96, 076602 (2006).
2. Yang, J., Tse, J. S., Yao, Y. & Iitaka, T. Structural and electronic properties of pristine and Ba-doped clathrate-like carbon fullerenes. Angewandte Chemie International Edition 46, 6275–6277 (2007).
Squashed carbon balls show promising electronic properties
Theoretical calculations have shown that an exciting new material—made by squashing together latticework balls of carbon atoms—could be a superconductor.
Such superconductors are widely sought, since they carry electricity with no resistance and could be used to make extremely efficient energy transfer and storage systems.
Materials containing a cage-like structure of atoms, known as clathrates, have shown promise as superconductors. Scientists led by Shoji Yamanaka from Hiroshima University recently made a new clathrate1 based on buckminsterfullerene (C60)—a hollow molecule made of sixty carbon atoms arranged into a soccer ball shape. High temperatures and pressures were used to squeeze the balls together until they became interconnected cubes of carbon, dubbed clathrate-C60 (Fig. 1).
Toshiaki Iitaka of RIKEN’s Discovery Research Institute in Wako and colleagues from the University of Saskatchewan in Saskatoon, Canada, led by John Sak Tse, have now calculated the structural and electronic properties of this material, and report their results in the international edition of Angewandte Chemie2.
They found that pure clathrate-C60 is metallic, and suggest that it could be a superconductor. Recent experiments have confirmed that clathrate-C60 is weakly metallic, but found no superconductivity even at the low temperature of –269 ˚C: just four degrees above the coldest temperature possible, known as absolute zero. Colder temperatures even closer to absolute zero may be needed to uncover the predicted superconductivity, the team suggests.
The structure of clathrate-C60 allows individual metal atoms to sit either inside, or between, each of the carbon cages. The team looked at how adding barium—just the right size to fit in either space—would alter the material’s properties.
The team also found that in both cases, adding barium would release heat energy from the material, making the overall structure more stable. Although the compounds have not been made, this result means that the compounds should be achievable experimentally, the team says.
Further calculations revealed that if the barium atoms sit inside the carbon cages, they lose an electron—this does not change the overall structure by much, but it turns the material into a semiconductor. Conversely, adding barium atoms into the spaces between the carbon cages distorts the overall structure. The metal atoms also lose less charge, and the material remains metallic.
These changes in electronic properties suggest that clathrate-C60 “may potentially be an important electronic material for technology applications,” the scientists predict.
1. Yamanaka, S., Kubo, A., Inumaru, K., Komaguchi, K., Kini, N.S., Inoue, T. & Irifune, T. Electron conductive three-dimensional polymer of cuboidal C60. Physical Review Letters 96, 076602 (2006).
2. Yang, J., Tse, J. S., Yao, Y. & Iitaka, T. Structural and electronic properties of pristine and Ba-doped clathrate-like carbon fullerenes. Angewandte Chemie International Edition 46, 6275–6277 (2007).
Microwaved electrons
Physicists have long known that, when cooled to very low temperatures, electrons can be placed on the surface of liquefied helium. Now, researchers from the RIKEN Discovery Research Institute, Wako, in collaboration with colleagues at Japan’s Keio University, Yokohama, have discovered they can effectively excite these electrons using microwave radiation.
At these extremely low temperatures—just above absolute zero—the electrons are stabilized by tiny electrical fields at the surface of the liquid helium, leading to an arrangement of electrons into regular two-dimensional patterns. Recently, scientists in the US proposed that these ordered charges could be used for quantum computing applications, which triggered intense studies in laboratories around the world. To achieve the necessary control of the electron states, the use of microwave radiation was suggested as a way to excite the electrons from one energy state to the other and thereby modify their quantum computing behavior.
Reporting in the journal Physical Review Letters (1), the researchers have studied the influence of microwave radiation on the electrons by measuring the electrical resistance across the floating electrons (Fig. 1). Increased resistivity is a sign of excited and heated electrons. Such measurements provide a relatively accurate picture of the state of the electrons, as “this system is an extremely clean and transparent electron system that provides a direct relationship between experiment and theory,” comments Kimitoshi Kono from the RIKEN team.
Surprisingly, the researchers found that as the temperature is lowered the change in resistivity of the electrons increases significantly through microwave irradiation. The measured values are much higher than estimated in previous theoretical studies. In fact, the sensitivity of the system’s electric current to the microwave radiation is so high that it could even be used as an efficient microwave detector. Regardless, this change in resistivity is a clear sign of an increased electron temperature and therefore of excitation of electrons into higher energy states. In particular, the researchers found that electrons are scattered away from the surface, which significantly reduces the suitability of such microwave-controlled electrons for quantum computing.
Unfortunately, “this is an important limitation towards the realization of quantum computers,” says Kono. To further pursue quantum computing applications, physicists must confine the lateral motion of electrons. For example, nanostructures around the surface could create suitable electric potentials to suppress increases in electron temperature. Therefore, Kono remains convinced that “quantum computing is still possible in this system.”
1. Konstantinov, D., Isshiki, H., Monarkha, Y., Akimoto, H., Shirahama, K. & Kono, K. Microwave-resonance-induced resistivity: evidence of ultrahot surface-state electrons. Physical Review Letters 98, 235302 (2007).
Physicists have long known that, when cooled to very low temperatures, electrons can be placed on the surface of liquefied helium. Now, researchers from the RIKEN Discovery Research Institute, Wako, in collaboration with colleagues at Japan’s Keio University, Yokohama, have discovered they can effectively excite these electrons using microwave radiation.
At these extremely low temperatures—just above absolute zero—the electrons are stabilized by tiny electrical fields at the surface of the liquid helium, leading to an arrangement of electrons into regular two-dimensional patterns. Recently, scientists in the US proposed that these ordered charges could be used for quantum computing applications, which triggered intense studies in laboratories around the world. To achieve the necessary control of the electron states, the use of microwave radiation was suggested as a way to excite the electrons from one energy state to the other and thereby modify their quantum computing behavior.
Reporting in the journal Physical Review Letters (1), the researchers have studied the influence of microwave radiation on the electrons by measuring the electrical resistance across the floating electrons (Fig. 1). Increased resistivity is a sign of excited and heated electrons. Such measurements provide a relatively accurate picture of the state of the electrons, as “this system is an extremely clean and transparent electron system that provides a direct relationship between experiment and theory,” comments Kimitoshi Kono from the RIKEN team.
Surprisingly, the researchers found that as the temperature is lowered the change in resistivity of the electrons increases significantly through microwave irradiation. The measured values are much higher than estimated in previous theoretical studies. In fact, the sensitivity of the system’s electric current to the microwave radiation is so high that it could even be used as an efficient microwave detector. Regardless, this change in resistivity is a clear sign of an increased electron temperature and therefore of excitation of electrons into higher energy states. In particular, the researchers found that electrons are scattered away from the surface, which significantly reduces the suitability of such microwave-controlled electrons for quantum computing.
Unfortunately, “this is an important limitation towards the realization of quantum computers,” says Kono. To further pursue quantum computing applications, physicists must confine the lateral motion of electrons. For example, nanostructures around the surface could create suitable electric potentials to suppress increases in electron temperature. Therefore, Kono remains convinced that “quantum computing is still possible in this system.”
1. Konstantinov, D., Isshiki, H., Monarkha, Y., Akimoto, H., Shirahama, K. & Kono, K. Microwave-resonance-induced resistivity: evidence of ultrahot surface-state electrons. Physical Review Letters 98, 235302 (2007).
High-temperature superconductivity: An organic perspective
High-temperature superconductivity, discovered in a variety of copper oxide materials, has been known for over 20 years, yet is still poorly understood. For example, unlike conventional superconductors, high-temperature superconductors do not simply transform to a normal metal when heated above the superconducting transition temperature: at these higher temperatures, a form of fluctuating superconductivity is present, as if the material cannot decide whether or not it is a metal or a superconductor.
Arzhang Ardavan and colleagues report similar behaviour in a very different type of material: superconducting organic metals. In this class of metals, these enigmatic fluctuations are most pronounced in samples that are close to being in a very different electronic state — a so-called ’Mott insulator’. Given that the non-superconducting relatives of the high-temperature superconductors are also Mott insulators, these findings suggest that a similar underlying mechanism drives this behaviour in both types of material.
CONTACT
Arzhang Ardavan (University of Oxford, UK)
Tel: +44 1865 272 366; E-mail: arzhang.ardavan@physics.ox.ac.uk
High-temperature superconductivity, discovered in a variety of copper oxide materials, has been known for over 20 years, yet is still poorly understood. For example, unlike conventional superconductors, high-temperature superconductors do not simply transform to a normal metal when heated above the superconducting transition temperature: at these higher temperatures, a form of fluctuating superconductivity is present, as if the material cannot decide whether or not it is a metal or a superconductor.
Arzhang Ardavan and colleagues report similar behaviour in a very different type of material: superconducting organic metals. In this class of metals, these enigmatic fluctuations are most pronounced in samples that are close to being in a very different electronic state — a so-called ’Mott insulator’. Given that the non-superconducting relatives of the high-temperature superconductors are also Mott insulators, these findings suggest that a similar underlying mechanism drives this behaviour in both types of material.
CONTACT
Arzhang Ardavan (University of Oxford, UK)
Tel: +44 1865 272 366; E-mail: arzhang.ardavan@physics.ox.ac.uk
Anaesthesia without paralysis
A method for blocking the activity of specific pain-sensing neurons without affecting other sensory or motor neurons could be used to create a more targeted anaesthesia than is currently available. Bruce P. Bean and colleagues show that introducing a molecule that acts only from the inside of neurons, in combination with capsaicin – the active ingredient in chilli peppers – which opens TRPV1 channels, can be used to block pain and produce regional anaesthesia without the paralysis associated with most local anaesthetics.
The team report that the sodium-channel blocker QX-314 can be made to enter neurons through TRPV1 channels when co-applied with the TRPV1-channel opener capsaicin. In further experiments they demonstrate the same effect in vivo.
This could prove advantageous for generating local anaesthesia in situations in which preserving motor and non-painful sensations is desirable, such as childbirth or dental procedures, or for treating certain types of chronic pain, such as postherpetic neuralgia.
CONTACT
Bruce P. Bean (Harvard Medical School, Boston, MA, USA)
Tel: +1 617 432 1139; E-mail: bruce_bean@hms.harvard.edu
Edwin W McCleskey (Howard Hughes Medical Institute, Chevy Chase, MD, USA)
E-mail: mccleskeye@hhmi.org N&V author
A method for blocking the activity of specific pain-sensing neurons without affecting other sensory or motor neurons could be used to create a more targeted anaesthesia than is currently available. Bruce P. Bean and colleagues show that introducing a molecule that acts only from the inside of neurons, in combination with capsaicin – the active ingredient in chilli peppers – which opens TRPV1 channels, can be used to block pain and produce regional anaesthesia without the paralysis associated with most local anaesthetics.
The team report that the sodium-channel blocker QX-314 can be made to enter neurons through TRPV1 channels when co-applied with the TRPV1-channel opener capsaicin. In further experiments they demonstrate the same effect in vivo.
This could prove advantageous for generating local anaesthesia in situations in which preserving motor and non-painful sensations is desirable, such as childbirth or dental procedures, or for treating certain types of chronic pain, such as postherpetic neuralgia.
CONTACT
Bruce P. Bean (Harvard Medical School, Boston, MA, USA)
Tel: +1 617 432 1139; E-mail: bruce_bean@hms.harvard.edu
Edwin W McCleskey (Howard Hughes Medical Institute, Chevy Chase, MD, USA)
E-mail: mccleskeye@hhmi.org N&V author
Monday, October 01, 2007
Mitochondrial downfall in Parkinson’s disease
The mutation of two genes associated with the development of Parkinson’s disease cooperate to regulate mitochondrial function when cells are stressed. This link will help researchers understand the mechanisms underlying the neuronal degeneration seen in pathologies such as Parkinson‘s disease.
Julian Downward and colleagues investigated the mitochondrial protease Omi – the loss of which leads to a neurodegenerative disorder resembling Parkinson’s. They found that Omi is regulated by PINK1, which has been identified as an early-onset Parkinson’s disease susceptibility factor. The researchers show that, in response to various cellular stresses, PINK1 is essential for mitochondrial protection by Omi and keeps cells healthy. Strikingly, they also find that this cooperation is impaired in brain samples from Parkinson's disease patients carrying mutations in PINK1.
Finding this new interaction suggests that in the normal brain, PINK1 and Omi prevent the death of neuronal cells by protecting their mitochondria. The development of Parkinson’s disease would thus be linked to a higher susceptibility to neuronal death following stress.
Author contact:
Julian Downward (Cancer Research UK, London, UK)
Tel: +44 207 269 3533; E-mail: julian.downward@cancer.org.uk
The mutation of two genes associated with the development of Parkinson’s disease cooperate to regulate mitochondrial function when cells are stressed. This link will help researchers understand the mechanisms underlying the neuronal degeneration seen in pathologies such as Parkinson‘s disease.
Julian Downward and colleagues investigated the mitochondrial protease Omi – the loss of which leads to a neurodegenerative disorder resembling Parkinson’s. They found that Omi is regulated by PINK1, which has been identified as an early-onset Parkinson’s disease susceptibility factor. The researchers show that, in response to various cellular stresses, PINK1 is essential for mitochondrial protection by Omi and keeps cells healthy. Strikingly, they also find that this cooperation is impaired in brain samples from Parkinson's disease patients carrying mutations in PINK1.
Finding this new interaction suggests that in the normal brain, PINK1 and Omi prevent the death of neuronal cells by protecting their mitochondria. The development of Parkinson’s disease would thus be linked to a higher susceptibility to neuronal death following stress.
Author contact:
Julian Downward (Cancer Research UK, London, UK)
Tel: +44 207 269 3533; E-mail: julian.downward@cancer.org.uk
Learning in stressful times
The hippocampus is crucial for mediating the effects of stress on learning, even when this brain region is not directly involved in learning the task in question.
The hippocampus is important for some types of learning but not others. Eyeblink conditioning, for example, does not require the hippocampus. Animals respond to a shock to the eye by blinking, and when the shock is repeatedly paired with a noise learn to respond to the noise itself with an eyeblink – irrespective of whether it is accompanied by a shock.
Tracey Shors and colleagues previously reported that after rats have been stressed, eyeblink conditioning is enhanced in males and reduced in females – stress therefore modifies learning of the association between the noise and shock. The authors now find that selective damage to the hippocampus in rats makes these stress-induced modifications disappear. Lesioned male rats do not learn eyeblink conditioning any faster when they are stressed, and lesioned female rats are no worse. Without stress, both perform just like normal animals. These results indicate that neuronal activity in the hippocampus modifies learning after stress, even when the hippocampus is not directly involved in the learning process itself.
Author contact:
Tracey Shors (Rutgers University, Piscataway, NJ, USA)
Tel: +1 732 445 6968; E-mail: shors@rutgers.edu
The hippocampus is crucial for mediating the effects of stress on learning, even when this brain region is not directly involved in learning the task in question.
The hippocampus is important for some types of learning but not others. Eyeblink conditioning, for example, does not require the hippocampus. Animals respond to a shock to the eye by blinking, and when the shock is repeatedly paired with a noise learn to respond to the noise itself with an eyeblink – irrespective of whether it is accompanied by a shock.
Tracey Shors and colleagues previously reported that after rats have been stressed, eyeblink conditioning is enhanced in males and reduced in females – stress therefore modifies learning of the association between the noise and shock. The authors now find that selective damage to the hippocampus in rats makes these stress-induced modifications disappear. Lesioned male rats do not learn eyeblink conditioning any faster when they are stressed, and lesioned female rats are no worse. Without stress, both perform just like normal animals. These results indicate that neuronal activity in the hippocampus modifies learning after stress, even when the hippocampus is not directly involved in the learning process itself.
Author contact:
Tracey Shors (Rutgers University, Piscataway, NJ, USA)
Tel: +1 732 445 6968; E-mail: shors@rutgers.edu
The gene-mapper’s best friend
Genetic variants associated with dominant or recessive disease-related traits in dogs can be mapped efficiently and with high confidence. As dogs and humans have a similar complement of genes, the mapping of disease-associated variants in dogs may make an important contribution to the study of human genetic disease.
There are more than 400 genetically distinct dog breeds. As each breed originated in a small number of founder dogs, there is a limited amount of genetic diversity within each breed. This sort of genome structure is ideal for the rough mapping of genes because it allows one to analyze most of the genome with a limited number of genetic markers. Kerstin Lindblad-Toh and colleagues found small regions of the genome to be associated with two traits by assessing a relatively small number of single-nucleotide polymorphisms (27,000) in only 20 dogs.
The authors identified a genomic region containing only one gene—MITF—as responsible for the absence of skin and coat pigmentation in white boxers, which also predisposes them to deafness. They also identified a region associated with the dorsal hair ridge in Ridgeback dogs, which are prone to dermoid sinus, a neural tube defect. In the accompanying paper, Leif Andersson and colleagues carried out fine mapping of the region associated with the Ridgeback hair ridge, and showed that the causative mutation is a duplication containing four different genes—FGF3, FGF4, FGF19 and ORAOV1.
Author contacts:
Kerstin Lindblad-Toh (Broad Institute of Harvard and MIT, Cambridge, MA, USA)
Tel: +1 617 252 1477; E-mail: kersli@broad.mit.edu
Genetic variants associated with dominant or recessive disease-related traits in dogs can be mapped efficiently and with high confidence. As dogs and humans have a similar complement of genes, the mapping of disease-associated variants in dogs may make an important contribution to the study of human genetic disease.
There are more than 400 genetically distinct dog breeds. As each breed originated in a small number of founder dogs, there is a limited amount of genetic diversity within each breed. This sort of genome structure is ideal for the rough mapping of genes because it allows one to analyze most of the genome with a limited number of genetic markers. Kerstin Lindblad-Toh and colleagues found small regions of the genome to be associated with two traits by assessing a relatively small number of single-nucleotide polymorphisms (27,000) in only 20 dogs.
The authors identified a genomic region containing only one gene—MITF—as responsible for the absence of skin and coat pigmentation in white boxers, which also predisposes them to deafness. They also identified a region associated with the dorsal hair ridge in Ridgeback dogs, which are prone to dermoid sinus, a neural tube defect. In the accompanying paper, Leif Andersson and colleagues carried out fine mapping of the region associated with the Ridgeback hair ridge, and showed that the causative mutation is a duplication containing four different genes—FGF3, FGF4, FGF19 and ORAOV1.
Author contacts:
Kerstin Lindblad-Toh (Broad Institute of Harvard and MIT, Cambridge, MA, USA)
Tel: +1 617 252 1477; E-mail: kersli@broad.mit.edu
The long and the short of fatty liver
Too much fat in the liver predisposes to diabetes, but a study reports that not all types of fat are equally harmful. Changing the fat composition in the liver may therefore help obese patients who are insulin resistant and cannot lose weight.
Excessive fat intake leads to obesity and overwhelms the storage capacity of fat cells, with surplus fat being stored in the liver. Development of fatty liver can result in insulin resistance and increased glucose levels—two hallmarks of diabetes.
Hitoshi Shimano and his colleagues created a strain of mice lacking Elovl6, an enzyme that increases the length of the carbon chains of fatty acids, thereby changing the fat composition in the liver of these mutant mice, with shorter fatty acids predominating over those with longer chains. On a high-fat diet, these mice became obese and developed fatty liver, just like wild-type mice, but their insulin sensitivity and their sugar levels were not affected.
The absolute levels of fat in the liver do not therefore seem to be detrimental to maintaining normal glucose levels. Instead, the types of fat that are present seem to be a more important factor, with shorter fat molecules being healthier than longer ones. If this is also true in humans, it may be possible to help obese patients who are insulin resistant and cannot lose weight by targeting Elovl6.
Author contact:
Hitoshi Shimano (University of Tsukuba, Ibaraki, Japan)
Tel: +81 29 853 3053; E-mail: shimano-tky@umin.ac.jp
Too much fat in the liver predisposes to diabetes, but a study reports that not all types of fat are equally harmful. Changing the fat composition in the liver may therefore help obese patients who are insulin resistant and cannot lose weight.
Excessive fat intake leads to obesity and overwhelms the storage capacity of fat cells, with surplus fat being stored in the liver. Development of fatty liver can result in insulin resistance and increased glucose levels—two hallmarks of diabetes.
Hitoshi Shimano and his colleagues created a strain of mice lacking Elovl6, an enzyme that increases the length of the carbon chains of fatty acids, thereby changing the fat composition in the liver of these mutant mice, with shorter fatty acids predominating over those with longer chains. On a high-fat diet, these mice became obese and developed fatty liver, just like wild-type mice, but their insulin sensitivity and their sugar levels were not affected.
The absolute levels of fat in the liver do not therefore seem to be detrimental to maintaining normal glucose levels. Instead, the types of fat that are present seem to be a more important factor, with shorter fat molecules being healthier than longer ones. If this is also true in humans, it may be possible to help obese patients who are insulin resistant and cannot lose weight by targeting Elovl6.
Author contact:
Hitoshi Shimano (University of Tsukuba, Ibaraki, Japan)
Tel: +81 29 853 3053; E-mail: shimano-tky@umin.ac.jp
Human evolution: The eastern extent of Neanderthals
Neanderthals could have spread as far east as central Asia and Siberia — more than 2,000 kilometres further than previously thought — according to new DNA evidence.
Neanderthal fossils have previously been found over a large area, stretching from the Mediterranean to as far east as Uzbekistan. Most remains are fragmentary, however, so it can be difficult to determine whether a fossil is of Neanderthal or of modern human origin.
Svante Pääbo and colleagues looked at mitochondrial DNA (mtDNA) sequences from two sets of hominid remains — one child skeleton from Uzbekistan and adult fossils from Okladnikov in southern Siberia — to find out whether they fell within the European Neanderthal mtDNA variation. The partial skeleton from Teshik-Tash in Uzbekistan is of an 8–10-year-old boy discovered in the 1930s. This fossil is thought to represent the easternmost extent of the Neanderthal range, but scientists have never been able to confirm it. The authors extracted mtDNA samples from four bones: the left femur of the Teshik-Tash child and three fragmentary pieces from the Siberian fossils.
The results show that the mtDNA fossil sequences fall within the European Neanderthal mtDNA variation, suggesting that the geographical range of Neanderthals extended farther east into southern Siberia than has generally been assumed. The authors conclude that further DNA sequences from across the Neanderthal range are needed to build up a better picture of how Neanderthals colonized different regions, and whether they ever reached as far east as Mongolia or China.
Author contact:
Svante Pääbo (Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany)
Tel: +49 341 3550 501; E-mail: paabo@eva.mpg.de
Neanderthals could have spread as far east as central Asia and Siberia — more than 2,000 kilometres further than previously thought — according to new DNA evidence.
Neanderthal fossils have previously been found over a large area, stretching from the Mediterranean to as far east as Uzbekistan. Most remains are fragmentary, however, so it can be difficult to determine whether a fossil is of Neanderthal or of modern human origin.
Svante Pääbo and colleagues looked at mitochondrial DNA (mtDNA) sequences from two sets of hominid remains — one child skeleton from Uzbekistan and adult fossils from Okladnikov in southern Siberia — to find out whether they fell within the European Neanderthal mtDNA variation. The partial skeleton from Teshik-Tash in Uzbekistan is of an 8–10-year-old boy discovered in the 1930s. This fossil is thought to represent the easternmost extent of the Neanderthal range, but scientists have never been able to confirm it. The authors extracted mtDNA samples from four bones: the left femur of the Teshik-Tash child and three fragmentary pieces from the Siberian fossils.
The results show that the mtDNA fossil sequences fall within the European Neanderthal mtDNA variation, suggesting that the geographical range of Neanderthals extended farther east into southern Siberia than has generally been assumed. The authors conclude that further DNA sequences from across the Neanderthal range are needed to build up a better picture of how Neanderthals colonized different regions, and whether they ever reached as far east as Mongolia or China.
Author contact:
Svante Pääbo (Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany)
Tel: +49 341 3550 501; E-mail: paabo@eva.mpg.de
New type of Bismuth oxide nanoparticles
UPM researchers have developed BiOX, a new type of bismuth oxide nanoparticle, which is cheap and ecologically friendly to produce. Bismuth oxide is important in everyday life its non-toxic properties. It can be used as a substitute for lead, eradicating peptic ulcer bacteria, in cosmetics and in solid oxide fuel cell
BiOX: a New Material for Industry
Irmawati Ramli, Nor Hidayaty Kamarulzaman, Norfarizan Ngasriah Mhamat Nasudin, Taufiq-Yap Yun Hin, and Abdul Halim Abdullah
Bismuth oxide is becoming so important in everyday life for its non-toxic and non-carcinogenic status. Demand is rising to use the material as a substitute for lead particularly in copper alloys for plumbing fittings for water drinking system. Suggestions have also been made for including the material in tableware glazing, glasses and crystal ware.
In pharmaceutical industries, the material is proven to be the most effective ingredient eradicating bacteria responsible for inflicting peptic ulcers. The material combined with chloride gives a special pearlescent, inimitable deep luster to lipstick, nail polish, eye shadows and facial powders in addition to its lubricating qualities for smoother, silkier skin comfort.
Other technological applications of bismuth oxide are in the field of advanced ceramics, rare earth chemicals, thermal spray powders, solid oxide fuel cell (SOFC) materials, catalysts, nano-magnetics, electroplating and biotechnology.
BiOX is a new type of bismuth oxide nanoparticle with distinctive bright orange colour. Its chemical symbol is Bi2O3 and its molecular weight is 466. The material particle size is 37nm with its corresponding specific surface area of 8.9m2g-1.
The oxides are of tetragonal-Bi2O3 which through controlled synthesis procedure produce materials resemble into rosette morphology (see attachment for images). The preparation method opted was rather simple and distinguished by the monophase composition of the product, ecological safety and simple operation, therefore promising low operating cost.
contact-
Dr.Irmawati binti Ramli
Address:Department of Chemistry
Faculty of Science
Universiti Putra Malaysia
43400 UPM Serdang
Selangor Darul Ehsan
MALAYSIA
Telephone:+ 603 8946 6786
Facsimile:+ 603 8943 5380
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