Measuring Blood Sugar With Light.


Technology designed in Germany may help people with Type 1 and Type 2 diabetes; described in Review of Scientific Instruments

WASHINGTON D.C. October 25, 2013 — One of the keys to healthful living with Type 1 and Type 2 diabetes is monitoring blood glucose (sugar) levels to ensure they remain at stable levels. People can easily and reliably do this at home using electronic devices that read sugar levels in a tiny drop of blood.

Now a team of German researchers has devised a novel, non-invasive way to make monitoring easier. Using infrared laser light applied on top of the skin, they measure sugar levels in the fluid in and under skin cells to read blood sugar levels. They describe their method in the current edition of Review of Scientific Instruments, which is produced by AIP Publishing.

“This opens the fantastic possibility that diabetes patients might be able to measure their glucose level without pricking and without test strips,” said lead researcher, Werner Mäntele, Ph.D. of Frankfurt’s Institut für Biophysik, Johann Wolfgang Goethe-Universität.

“Our goal is to devise an easier, more reliable and in the long-run, cheaper way to monitor blood glucose,” he added.

The “Sweet Melody” of Glucose

Their new optical approach uses photoacoustic spectroscopy (PAS) to measure glucose by its mid-infrared absorption of light. A painless pulse of laser light applied externally to the skin is absorbed by glucose molecules and creates a measurable sound signature that Dr. Mäntele’s team refers to as “the sweet melody of glucose.” This signal enables researchers to detect glucose in skin fluids in seconds.

The data showing the skin cell glucose levels at one-hundredth of a millimeter beneath the skin is related to blood glucose levels, Mäntele said, but previous attempts to use PAS in this manner have been hampered by distortion related to changes of air pressure, temperature and humidity caused by the contact with living skin.

To overcome these constraints, the team devised a design innovation of an open, windowless cell architecture. While it is still experimental and would have to be tested and approved by regulatory agencies before becoming commercially available, the team continues to refine it.

High Glucose Linked to Poorer Memory, Even in People Without Diabetes.


Higher levels of both short-term and long-term blood glucose markers are significantly associated with poorer memory and with decreased volume and microstructure of the hippocampus in persons without diabetes or impaired glucose tolerance (IGT), according to a new study.

The results imply that lowering blood glucose levels, possibly even to relatively low levels, might help preserve cognition, study author Agnes Flöel, MD, Department of Neurology and Center for Stroke Research Berlin, Charite-University Medicine, Berlin, Germany, toldMedscape Medical News.

Strategies that help lower blood glucose levels include a healthy Mediterranean-type diet and regular physical activity, she added.

The study is published online October 23 in Neurology.

Direct Relationship

The cross-sectional study included 141 healthy persons (mean age, 63.1 years) who were recruited through advertising. Persons with diabetes, IGT, or neurologic disorders and those taking antidepressants were excluded.

Researchers obtained blood measurements, including glycosylated hemoglobin (HbA1c), which reflects peripheral glucose levels of the preceding 8 to 12 weeks; fasting glucose; and insulin. They also carried out apolipoprotein E (APOE) genotyping.

Participants underwent cognitive testing using the German version of the Rey Auditory Verbal Learning Test. Researchers calculated hippocampal volume from MRI scans and assessed hippocampal microstructure by mean diffusivity (MD) estimated by using diffusion tensor imaging.

According to Dr. Flöel, this was the first time that this MD method provided data on the association between hippocampal microstructure and glucose metabolism.

The investigators found that lower performance on 3 memory tasks (delayed recall, learning ability, and consolidation) was associated with higher levels of both the long-term marker of glucose control (HbA1c) and the short-term glucose marker (all P ≤ .01).

For insulin, there was a “general trend going in the same direction” but correlations were less clear, and without the same direct relationship, said Dr. Flöel.

Potential Mechanisms

Memory performance was correlated with hippocampal volume (P = .001) and lower MD (P = .01), lower age, and, in part, lower blood pressure and female sex. Researchers did not find a statistically significant association between memory performance and APOE genotype, body mass index, Beck Depression Inventory score, physical activity, or smoking.

Lower levels of HbA1c were associated with larger hippocampal volume (nonsignificant trend; P = .06). The associations between lower fasting glucose levels and higher hippocampal volume did reach significance (P = .01). There was no significant relationship between hippocampal volume and insulin.

As for hippocampal microstructure, the researchers noted that lower levels of all 3 markers of glucose metabolism significantly correlated with lower MD within the hippocampus.

There was no significant association between glucose markers and volume or MD in brain areas other than the hippocampus (eg, gray matter and thalamus).

The hippocampus is particularly vulnerable to disturbances in metabolic supply, including glucose, said Dr. Flöel.

“Elevated blood sugar levels may damage the outer membrane of the cells, or decrease neurotransmitter levels, which would disturb signaling within and between hippocampal cells. Information transfer between cells, which is indispensable for memory encoding, storage and retrieval, would then be compromised.”

Elevated blood sugar levels may also damage small and large vessels in the brain, leading to decreased blood and nutrient flow to brain cells or even brain infarcts, and this may further damage memory-relevant brain structures, added Dr. Flöel.

The current findings are in line with studies of patients with type 2 diabetes mellitus and IGT, but earlier research was unable to confirm the deleterious effects of nondiabetic glucose levels on cognition. This, said the authors, may be because of different methods for classifying glucose levels and varying cognitive tests used.

Prevention Research

The authors also pointed out that the current study used MRI with higher magnetic field strength, which offers a higher sensitivity of hippocampal volumetry and greater statistical power to observe significant associations.

Following a diet high in lean protein and complex carbohydrates (such as whole grains, vegetables, fruits, and fiber) and low in heavily refined foods will help lower blood glucose, said Dr. Flöel. Another important lifestyle strategy is regular physical activity.

How low is it safe to go in terms of blood glucose levels? According to Dr. Flöel, that depends in part on lifestyle. “If you’re used to low blood sugar levels, you can go quite low,” she said.

She likened this to the situation with blood pressure. “At one time, it was assumed that you needed a certain level to function, but that actually is not true. You can go very low and still maintain normal function, and it might actually be better in the long run.”

Although the study uncovers the protective potential of lower blood glucose levels, the relationship between high blood glucose and poor memory “seems to be more linear” and changing recommended cutoffs may not make much of a difference, said Dr. Flöel.

On the other hand, what could be key is prevention, she said.

“There have been some initiatives to put prevention more on the agenda of dementia research,” she said. “There has been so much money spent on treatment of Alzheimer’s disease and it has already been established that this is not very successful. “

Dementia prevention strategies could include taking measures at an earlier stage to encourage physical fitness and control hypertension, blood lipids (including cholesterol and triglycerides), and now, possibly, blood glucose levels, she said.

Patients should have their fasting glucose and HbA1c levels measured as part of a regular medical check-up starting at age 55 years, unless there’s a personal or family history of diabetes or the patient is obese, in which case the family doctor may opt for earlier and more intense monitoring, said Dr. Flöel. She pointed out that such tests are easy to do and are already carried out regularly in pregnant women.

Fresh Eyes

Commenting on the findings for Medscape Medical News, Marwan N. Sabbagh, director, Banner Sun Health Research Institute, Sun City, Arizona, said that the study looks at the link between glucose metabolism and cognition with fresh eyes.

“This is saying that immediate learning and A1c levels, and potentially even blood sugars, interact even in people who are nondemented, and I don’t think anyone has looked at it that way before,” said Dr. Sabbagh.

“The idea is that the lower the A1c the better your brain function. This is a very exciting development and clearly helps put a frame around the Alzheimer’s discussion, but more importantly, it talks about how blood sugar metabolism and cognitive function directly interact.”

The study opens “a whole new territory” because until now, HbA1c and blood glucose have been looked at only in the context of diabetes and the risk for diabetes, added Dr. Sabbagh. “Maybe we need to rethink our normalization of glucose with an eye toward cognition and not simply a diabetes risk.”

Uncovering the tricks of nature’s ice-seeding bacteria


Like the Marvel Comics superhero Iceman, some bacteria have harnessed frozen water as a weapon. Species such as Pseudomonas syringae have special proteins embedded in their outer membranes that help ice crystals form, and they use them to trigger frost formation at warmer than normal temperatures on plants, later invading through the damaged tissue. When the bacteria die, many of the proteins are wafted up into the atmosphere, where they can alter the weather by seeding clouds and precipitation.

Now scientists from Germany have observed for the first time the step-by-step, microscopic-level action of P. syringae‘s ice-nucleating proteins locking water molecules in place to form ice. The team will present their findings at the AVS 60th International Symposium and Exhibition, held Oct. 27 – Nov. 1 in Long Beach, Calif.

“Ice nucleating proteins are the most effective ice nucleators known,” said Tobias Weidner, leader of the surface protein group at the Max Planck Institute for Polymer Research. The proteins jump-start the process of ice crystal formation so well that dried ice-nucleating bacteria are often used as additives in snowmakers.

Although scientists discovered ice-nucleating proteins decades ago, little is known about how they actually work. Weidner and his team tackled the mystery with a powerful tool called spectroscopy that can decipher patterns in the interaction between light and matter to visualize the freezing process in layers of materials only a few molecules thick.

The researchers prepared a sample of fragments of P. syringae bacteria that they spread over water to form a surface film. As the temperature was lowered from room temperature to near freezing levels the scientists probed the interface between the bacterial proteins and the water with two laser beams. The beams combined within the sample and a single beam was emitted back, carrying with it information about how the protein and water molecules move and interact.

By analyzing the returning light beam’s frequency components, Weidner and his colleagues found a surprisingly dramatic result: as the temperature approached zero degrees Celcius the water molecules at the ice-nucleating protein surface suddenly became more ordered and the molecular motions become sluggish. They also found that thermal energy was very efficiently removed from the surrounding water. The results indicate that ice nucleating proteins might have a specific mechanism for heat removal and ordering water that is activated at low temperatures, Weidner said.

“We were very surprised by these results,” Weidner added. “When we first saw the dramatic increase of water order with lower temperatures we believed it was an artifact.” The movements of the water molecules near the ice-nucleating protein was very different than the way water had interacted with the many other proteins, lipids, carbohydrates, and other biomolecules the team had studied.

Recent studies have shown that large numbers of bacterial ice-nucleating proteins become airborne over areas like the Amazon rainforest and can spread around the globe. The proteins are among the most effective promoters of ice particle formation in the atmosphere, and have the potential to significantly influence weather patterns. Learning how P. syringae triggers frost could help teach researchers how ice particle formation occurs in the upper atmosphere.

“Understanding at the microscopic level – down to the interaction of specific protein sites with water molecules – the mechanism of protein-induced atmospheric ice formation will help us understand biogenic impacts on atmospheric processes and the climate,” Weidner said. For a more detailed picture of protein-water interactions it will also be important to combine their spectroscopic results with computer models, he said.

Blood sugar levels could be linked to memory loss in people without diabetes – Mirror.co.uk


Journal study finds with with lower blood sugar levels achieved highest scores in memory tests – those with high levels could suffer memory loss

People who have even slightly raised blood sugar levels may suffer memory loss, a study shows.

Researchers performed tests on 141 healthy people with an average age of 63.

None had diabetes or pre-diabetic symptoms.

But the study published in journal Neurology found those with with lower blood sugar levels achieved better scores in memory tests.

In a test to recall 15 words 30 minutes after hearing them, higher blood sugar levels were linked with poorer memory.

Lead researcher Dr Agnes Floel, of the Charite University Medicine in Berlin, Germany, said: “These results suggest that even for people within the normal range of blood sugar, lowering their blood sugar levels could be a promising strategy for preventing memory problems and cognitive decline as they age.

“Strategies such as lowering calorie intake and increasing physical activity should be tested.”

Dr Clare Walton, of the Alzheimer’s Society, said: “We already know that Type 2 diabetes is a risk factor for developing Alzheimer’s disease but this new study suggests that higher blood sugar levels may also be linked to poor memory in people without diabetes.

“The research suggests that regulating blood sugar levels might be a way to improve people’s memory, even if they don’t have diabetes.”

Dr Simon Ridley, of Alzheimer’s Research UK, added: “While we do not know whether the people in this study would have gone on to develop dementia, the findings serve as a warning that we should be conscious of the impact that subtle changes in our health could have on our brain.

“Current evidence suggests the best way to keep the brain healthy is to eat a balanced diet, take regular exercise, maintain a healthy weight, not smoke and keep blood pressure and cholesterol levels in check.”

Europe Launches Space Metal 3D Printing Project.


The European Space Agency has rolled out a new initiative to refine 3D printing techniques to make space-grade metal parts.

The project, called AMAZE, aims to spur innovations that could one day allow astronauts to print their own metal tools aboard the International Space Station or let engineers on the ground to print entire satellites.

3D printing, or additive manufacturing, builds solid objects from a series of layers, typically by melting powder or wire materials. This technique can produce complex structures with more flexibility and less waste than traditional manufacturing, which could translate into big cost and time savings. . [Photos: ESA’s AMAZE Space Metal 3D Printing Project.

Billed as the world’s largest metal 3D-printing project, ESA’s initiative brings together 28 industrial partners across the continent. AMAZE is short for Additive Manufacturing Aiming Towards Zero Waste and Efficient Production of High-Tech Metal Products.

“We want to build the best quality metal products ever made,” David Jarvis, ESA’s Head of New Materials and Energy Research, said in a statement when the project was unveiled last week at the London Science Museum.

The group is focusing on making space-quality components by using lasers, electron beams and even plasma to melt metal alloys, Jarvis explained. The project also aims to explore the possibility of combining strong and lightweight, but more exotic metals, such as tungsten, niobium and platinum, though these materials are expensive.

As part of the initiative, four pilot 3D printing-factories are being established in Germany, Italy, Norway and the United Kingdom. David wants to help standardize the technique and bring it to the mainstream, connecting key players in the metallic 3D printing business to develop a supply chain.

Titanium Printed Structure

ESA officials say innovations along the way to make 3D printers more viable for spacecraft could have benefits on Earth, leading to improvements in aircraft wings, jet engines and automotive systems.

ESA is hardly alone in its ambition to perfect metal 3D printing for the final frontier. Among several other NASA endeavors in additive manufacturing, the U.S. space agency recently completed a successful hot-fire test of the biggest 3D-printed rocket part built to date: an engine injector printed with nickel-chromium alloy powder.

There are several private and university-led efforts, too. Earlier this month, a group of students at the University of California, San Diego performed their first test of a 3D-printed engine made from cobalt chromium.

Materials Prediction Scores a Hit


 Figure 1

 The energetics of predicting materials. A schematic free energy landscape for different crystallographic configurations is given by the blue line. Note the small difference in energy between various structures compared with the total energy of a crystal demanding high computational accuracy. The application of pressure as done by Gou et al. will modify the energy landscape (red curve), potentially stabilizing new structures. The ground state (such as superconductivity, magnetism, or other forms of order) for a given structure is determined at even lower energy scales, as depicted in the inset. The addition of strong electronic correlations in some materials will further modify the landscape over large energy scales up to 10eV, making predictions even more challenging.

Had the great American philosopher Yogi Berra been a condensed matter physicist, he might have said “It’s difficult to make predictions, especially about superconductivity.” Predictions about a material’s structure and even more so its function have been goals of materials research for a long time, but the track record for predicting that a given compound will superconduct is notoriously bad [1]. Fortunately, advances in the fidelity and resolution of electronic structure calculations are beginning to change this trend [2]. In fact, the White House’s Materials Genome Initiative [3] represents a recognition that with recent advances in computational capability and materials models, such breakthroughs are possible and, in fact, likely probable. In a paper in Physical Review Letters, Huiyang Gou at the University of Bayreuth, Germany, and colleagues [4] describe a success story in the search for predictability. They report the observation of superconductivity in iron tetraboride (FeB4) at approximately 3 kelvin (K). Not only did they find superconductivity where electronic structure calculations told them to look, they used high-pressure synthesis techniques to discover a compound that wasn’t readily apparent in nature. Further, the resulting compound, orthorhombic FeB4, turns out to be very mechanically hard as well as superconducting, thus possessing two desirable traits.

Most attempts to predict superconductivity invoke the physicist Bernd Matthias [5]. In the 1950s–1970s Matthias articulated a number of empirical “rules” that anticipated a large number of superconducting materials based on crystal structure and the number of valence electrons per atom. However, these rules were clearly based on intuition and not predictive theory. The experimental discovery that cuprates, magnesium diboride (MgB2), and more recently, iron pnictides all superconduct drove home the reality that serendipity was still the best materials discovery engine. However, that reality is beginning to evolve.

Why is it so difficult to predict new superconducting materials? One issue is the difficulty predicting the structural stability of a compound, that is, whether the binding energy between atoms is large enough to keep them stuck together in a particular configuration. Electronic structure calculations provide the total energy for a crystal, which is on the order of 105 electron volts per atom (eV/atom) (see Fig. 1). However, the stability with respect to competing phases is typically as small as 10-2 eV/atom, thus demanding incredibly high accuracy of the calculations. Furthermore, calculations are typically performed at T=0K in ideal crystals, while the thermal energy at which the crystals are synthesized and the energy scale created by defects can easily shift the relative total energies of competing phases by similar amounts. Another factor is that superconductivity is a very low-energy instability of the electronic structure. For a superconductor with a transition temperature Tc of 3K, as discovered by Gou et al., this amounts to an energy scale of 10-4eV. Few predictive models (yet) have accuracy at the parts per billion level covered by these energy scales.

Advanced electronic structure calculations for predictions have increased effectiveness due to the relative accessibility and availability of high-pressure techniques. Recent discoveries demonstrate that surprises still exist at high pressure [6]. We now know that a dozen or so additional elements superconduct at elevated pressure even though they are normal materials under ambient conditions, including calcium at 220 gigapascals (with Tc=29K, the highest Tc for an elemental superconductor). More broadly, materials science has been transformed by our ability to apply sufficient pressure to tune structural energetics on this scale to make new states of matter available.

In 2010, Kolmogorov, a coauthor of the present study, and colleagues predicted additional phases in the iron–boron (Fe-B) binary phase diagram that had yet to be observed [7]. They used a high-throughput search method coupled to an evolutionary algorithm to identify new structures for which superconductivity was theoretically evaluated. Subsequently, Bialon et al. suggested that the stability of iron tetraboride (FeB4) would be enhanced under pressure, and predicted the material’s hardness [8]. In the present manuscript, Gou et al. confirmed that FeB4 can be synthesized under pressure, and furthermore, that it possess the two novel predicted properties: superconductivity and high incompressibility. In addition, though not definitive, Gou et al. obtained preliminary data that superconductivity is phonon mediated like other conventional superconductors.

While the paper by Gou et al. gives promise that theory may finally be able to guide experimentalists where to look for conventional superconductors, it’s important to remember that the predicted Tc was 5 times too large in a structure that couldn’t be synthesized at ambient pressure. Further, the situation remains much more challenging for unconventional superconductors such as the cuprates, pnictides, heavy fermion materials, and organics. The biggest issue is that strong electronic correlations alter the electronic structure in these materials over an energy scale of order 1–10eV. While modern electronic structure calculations such as dynamical mean-field theory are making progress in understanding these effects, we currently lack the ability to reliably identify an additional superconducting instability on this strongly correlated background. How these electronic correlations modify the ability to compute structural stability of compounds also remains an open question. Given that superconductivity emerges in strongly correlated systems in ways we least expect it [9], future searches would be aided by guidance on where to find such correlations and competing electronic instabilities.

Gou et al. provide an encouraging step in the quest for materials by design, but one can also hope that this is a harbinger of even more and better things to come. Leveraging advanced computational capabilities and associated materials algorithms, together with synthetic techniques that allow broader access to phase space, including metastable materials, holds the exciting potential of delivering on the vision of the Materials Genome Initiative. We look forward to this, bearing in mind the quote attributed to Yogi Berra: “It’s difficult to make predictions, especially about the future.”

Acknowledgment

Our work in this area has been supported by the Department of Energy’s Office of Basic Energy Sciences Division of Materials Science and Engineering.

References

  1. I. I. Mazin, “Superconductivity Gets an Iron Boost,” Nature 464, 183 (2010).
  2. R. Akashi and R. Arita, “Development of Density-Functional Theory for a Plasmon-Assisted Superconducting State: Application to Lithium Under High Pressures,” Phys. Rev. Lett. 111, 057006 (2013).
  3. Materials Genome Initiative for Global Competitiveness, http://www.whitehouse.gov/blog/2011/06/24/materials-genome-initiative-renaissance-american-manufacturing.
  4. H. Gou et al., “Discovery of a Superhard Iron Tetraboride Superconductor,” Phys. Rev. Lett. 111, 157002 (2013).
  5. B. T. Matthias, T. H. Geballe, and V. B. Compton, “Superconductivity,” Rev. Mod. Phys. 35, 1 (1963).
  6. M. Sakata, Y. Nakamoto, K. Shimizu, T. Matsuoka, and Y. Ohishi, “Superconducting state of Ca-VII below a critical temperature of 29 K at a pressure of 216 GPa,” Phys. Rev. B 83, 220512(R) (2011).
  7. A. N. Kolmogorov, S. Shah, E. R. Margine, A. F. Bialon, T. Hammerschmidt, and R. Drautz, “New Superconducting and Semiconducting Fe-B Compounds Predicted with an Ab Initio Evolutionary Search,” Phys. Rev. Lett. 105, 217003 (2010).
  8. A. F. Bialon, T. Hammerschmidt, R. Drautz, S. Shah, E. R. Margine, and A. N. Kolmogorov, “Possible Routes for Synthesis of New Boron-Rich Fe–B and Fe1-xCrxB4 Compounds,” Appl. Phys. Lett. 98, 081901 (2011).
  9. Z. Fisk, H. R. Ott, and J. D. Thompson, “Superconducting materials: What the record tells us,” Philos. Mag. 89, 2111 (2009).

Wireless pacemaker comes to Europe.


A miniaturised, wireless pacemaker that can be inserted into the body without invasive surgery has been given approval for use in the European Union.

Developed by US start-up Nanostim, the device is designed to be implanted intravenously directly in the heart.

Nanostim pacemaker

It is less than 10% of the size of a conventional pacemaker and uses a built-in battery.

Experts said it was an “exciting development” but at a very early stage.

The pacemaker has yet to receive full US Food and Drug Administration (FDA) approval.

Conventional pacemakers require a patient to be cut open and a pocket created in the body to house the pacemaker and associated wires.

Such wires are regarded as the component of pacemakers most likely to fail. The pocket created for the pacemaker is also liable to infection.

By contrast the Nanostim pacemaker is delivered via a catheter inserted through the femoral vein near the groin.

It has a built-in battery, smaller than an AAA battery, that lasts between nine and 13 years. Eliminating the need for wires lowers the risk of infection or malfunction and means that patients are not restricted in the amount of activity they do, the firm behind the device claims.

The procedure to fit the pacemaker typically lasts around half an hour. The device is designed to be easily retrievable so that the battery can be replaced.

Because the device is delivered intravenously, it also means patients will have no scarring.

One doctor, involved in its trials, described it as “the future of pacemaking”.

“For the past 40 years the therapeutic promise of leadless pacing has been discussed, but until now, no-one has been able to overcome the technical challenges,” said Dr Johannes Sperzel of the Kerchhoff Klinik in Bad Nauheim, Germany.

“This revolutionary technology offers patients a safe, minimally-invasive option for pacemaker delivery that eliminates leads and surgical pockets,” he added.

Better understanding

But others were more cautious.

Prof Jeremy Pearson, associate medical director at the British Heart Foundation, said: “This is a potentially exciting development but it’s early days.

“Before this leadless pacemaker becomes widely available, we need a better understanding of how long it will last, as well as how easy it is to replace if necessary. As our knowledge of this new pacemaker widens, so too will the expertise needed to fit this potentially exciting device.”

The company behind the device has recently been bought by global medical device firm St Jude.

It has had several wire-based pacemakers recalled in recent years.

Other device makers are also planning to go wireless. The Wireless Cardiac Stimulation system has been developed by US start-up EBR Systems and UK-based tech firm Cambridge Consultants and uses a tiny wireless electrode no bigger than a grain of rice powered by an ultrasonic pulse generator, inserted lower down in the chest.

In 2011 the device was implanted in 100 patients in hospitals across Europe.

Cardiac pacemakers are used to treat slow heart rates. The devices monitor the heart and provide electrical stimulation when the heart beats too slowly.

The first pacemaker was fitted in 1958. Currently more than four million people around the world have some sort of cardiac rhythm device with an additional 700,000 people getting one each year.

Human Breast Milk Inactivates Hepatitis C Virus Infectivity.


 A new study shows why breastfeeding is generally safe even when mothers are infected with the hepatitis C virus (HCV).

The reason is that human breast milk inactivates hepatitis C virus (HCV) infectivity by disrupting its envelope, researchers from Germany have found.

“This study provides a novel mechanism for the protective properties of human mother’s milk against HCV,” Dr. Eike Steinmann from the TWINCORE Center for Experimental and Clinical Infection Research in Hannover told Reuters Health by email. “A new finding is that lipases in human milk generate free fatty acids that damage the viral envelope and render them non-infectious.”

In an editorial published with the paper online September 24 in The Journal of Infectious Diseases, Dr. Ravi Jhaveri from the University of North Carolina in Chapel Hill says “the results provide a plausible explanation for why breastfeeding is not a risk factor for HCV transmission. This is reassuring for us as practitioners when we counsel our HCV patients that it is safe for them to breastfeed.”

Using breast milk from healthy HCV-negative women, the research team found that even short preincubation periods of HCV in the milk brought consistent reductions of HCV infectivity by 2 to 3 orders of magnitude.

The breast milk inactivated HCV infectivity independent of the viral genotype, and antiviral activity was concentration dependent. Concentrations between 4% and 6% milk were sufficient to reduce HCV infectivity, whereas higher dilutions abolished the antiviral effect.

The antiviral activity was specific to human milk. It was not found in milk from horses, cows, or commercial infant formula.

The anti-viral activity was not destroyed by heat treatment, the authors reported.

In a series of experiments, the researchers showed that lipases in human milk generated fatty acids that disrupted the viral envelope, resulting in the loss of viral infectivity.

“Similar processes concerning the release of free fatty acids take place upon digestion of human breast milk by the infant,” the investigators note. “Therefore, milk digestion products, like free fatty acids, released in the stomach might be able to inactivate residual viral particles which otherwise could be transmitted upon breastfeeding.”

Human breast milk also had significant antiviral effects against other enveloped viruses (influenza, herpes simplex, and vesicular stomatitis virus) but no pronounced effect on non-enveloped viruses (murine norovirus, rotavirus).

“As there are far more enveloped viruses known than tested in this study, further investigations are necessary,” Dr. Steinmann said.

“Human breast milk efficiently inactivates HCV in vitro and neither the Centers for Disease Control nor the American Association for the Study of Liver Diseases argues against breastfeeding from HCV infected women unless they have cracked or bleeding nipples,” Dr. Steinmann concluded.

Dr. Jhaveri’s editorial concludes, “After reading this article, when we clinicians next encounter an HCV infected patient that just delivered a healthy infant and wants to breastfeed, we have yet another reason to say ‘Breast is Best.'”

First physical evidence of why you’re a morning or night person.


They say the early bird catches the worm, but night owls may be missing far more than just a tasty snack. Researchers have discovered the first physical evidence of structural brain differences that distinguish early risers from people who like to stay up late. The differences might help to explain why night owls seem to be at greater risk of depression.

Around 10 per cent of people qualify as morning people or larks, and a further 20 per cent are night owls – with the rest of us falling somewhere in between. Your lark or night owl status is called your chronotype.

Previous studies have suggested that night owls experience worse sleep, more tiredness during the day and consume greater amounts of tobacco and alcohol. This has prompted some to suggest that they are suffering from a form of chronic jet lag.

To investigate further, Jessica Rosenberg at RWTH Aachen University in Germany and colleagues used diffusion tensor imaging to scan the brains of 16 larks, 23 night owls and 20 intermediate chronotypes. They found a reduction in the integrity of night owls’ white matter – brain tissue largely comprised of fatty insulating material that speeds up the transmission of nerve signals – in areas associated with depression.

“We think this could be caused by the fact that late chronotypes suffer from this permanent jet lag,” says Rosenberg, although she cautions that further studies are needed to confirm cause and effect.

Skewed body clocks

Although the team controlled for tobacco and alcohol use, it’s possible that gene variants that skew people’s body clocks towards nocturnal living could affect the structure of the brain. It’s also not clear whether the structural changes have any implications for people’s health.

“It’s interesting that there are individual differences, but we need to understand what is causing them and find ways of creating environments in which those differences can be attenuated,” says Derk-Jan Dijk, director of the Surrey Sleep Research Centre in Guildford, UK, who was not involved in the study.

Rosenberg suggests that people’s work schedules should change to fit in with their natural sleep patterns, but Djik says there may be an easier way. For example, research published last month suggests that night owls who cut their exposure to artificial light and boosted their exposure to sunlight found their body clocks shifted towards earlier waking and sleeping

Source: newscientist.com

 

Researchers discover new form of 12-sided quasicrystal.


A team of researchers working at Germany‘s Martin-Luther-Universität has discovered a new form of a 12-sidded quasicrystal. In their paper published in the journal Nature, the team describes how they accidently created the previously unknown crystalline structured material while investigating interfacing properties between various substances.

Researchers discover new form of 12-sided quasicrystal

Quasicrystals are substances that look a lot like crystals but have one major exception—the  of their structure is non-repeating. They were first discovered in 1982 by Daniel Shechtman—he won the Nobel Prize in chemistry for it in 2011. Since that time they have been created in the lab in various ways and have even been found in nature—as part of a meteorite that fell in Russia (which because it was found to have been created by a non-heat related astrophysical process, showed that applying heat wasn’t necessary to create them). In this latest effort the researchers created one using perovskite oxides, potentially extending the number of  that can be created by such .

The team in Germany was investigating the ways perovskite behaved when used as a layer on top of a metal base. After exposure to extremely high temperatures, they noted that the material began to shape into a pattern, which they naturally assumed was a crystal. Upon closer inspection, they found that the 12-sided pattern didn’t repeat itself—the mark of a . The team notes that perovskite oxides are not normally noted for forming into quasicrystals, and in fact, no one really thought it was possible.

The discovery extends the types of quasicrystals that are known to exist, though not all of them have 12 sides of course. Their unusual structures make possible the creation of materials with unusual properties which scientists are just now beginning to find. Finding ways to create them using materials not normally associated with such odd structures may pave the way to a much broader array of end products—now that scientists know that it is possible, the door has been opened to creating all sorts of new materials from perovskite oxide based quasicrystals (now called barium titanate), such as thermal insulators or coatings for electronic components.


Abstract

The discovery of quasicrystals—crystalline structures that show order while lacking periodicity—forced a paradigm shift in crystallography. Initially limited to intermetallic systems, the observation of quasicrystalline structures has recently expanded to include ‘soft’ quasicrystals in the fields of colloidal and supermolecular chemistry. Here we report an aperiodic oxide that grows as a two-dimensional quasicrystal on a periodic single-element substrate. On a Pt(111) substrate with 3-fold symmetry, the perovskite barium titanate BaTiO3 forms a high-temperature interface-driven structure with 12-fold symmetry. The building blocks of this dodecagonal structure assemble with the theoretically predicted Stampfli–Gähler tiling having a fundamental length-scale of 0.69?nm. This example of interface-driven formation of ultrathin quasicrystals from a typical periodic perovskite oxide potentially extends the quasicrystal concept to a broader range of materials. In addition, it demonstrates that frustration at the interface between two periodic materials can drive a thin film into an aperiodic quasicrystalline phase, as proposed previously. Such structures might also find use as ultrathin buffer layers for the accommodation of large lattice mismatches in conventional epitaxy.