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To reach this record, Sergei Zherlitsyn and his colleagues at the High Magnetic Field Laboratory Dresden (HLD) developed a coil weighing about 200 kilograms in which electric current create the giant magnetic field – for a period of a few milliseconds. The coil survived the experiment unscathed.

With this record, we’re not really that interested in reaching top field values, but instead in using it for research in materials science, ”explains Joachim Wosnitza, the HLD’s Director. The scientists are actually proud of being the first user lab worldwide to make such high magnetic fields available for research. The more powerful a magnetic field is, the more precisely the scientists can examine those substances which are used for innovative electronic components or for so-called superconductors which conduct electricity without any resistance. Such high magnetic fields are generated by passing an electric current through a copper coil.

Hochfeld-Magnetlabor Dresden: Kondensatorbank

The capacitor bank of the Dresden High Magnetic Field Laboratory.

But the magnetic field also influences the electric current because it tries to push the electric current out of the coil. The stronger the current flows, the more powerful these forces are. “At 25 Tesla, the copper would be torn apart,” Joachim Wosnitza describes a potential scenario of this conflict between the magnetic field and the metal. In comparison: A standard commercial refrigerator magnet has 0.05 Tesla.

In order to examine as closely as possible the electric charge in the materials of tomorrow, researchers need higher magnetic fields with, for example, 90 or 100 Tesla. “At 100 Tesla, though, the Lorentz force inside the copper would generate a pressure which equals 40,000 times the air pressure at sea level,” calculates Joachim Wosnitza. These forces would tear copper apart like an explosion. That is why researchers use specific copper alloys which can withstand ten thousand times the atmospheric pressure. They then add a corset made from a special fiber that is typically used for bulletproof vests and which holds the alloy together from the outside. The HZDR technicians wind six of these special wires with corsets into a coil that has a hollow space of 16 millimeters at its center. This permits the generation of 50 Tesla within this special coil when a brief but powerful electric pulse flashes through the copper – a process that is over after a mere 0.02 seconds.

 Mitarbeiter des Hochfeld-Magnetlabors Dresden bereiten eine Magnetspule für ein Experiment vor

Magnetic coil.

But that’s still, though, far away from the world record of 89 Tesla which the US Americans held in Los Alamos for several years. And that is why the technicians put a second coil consisting of twelve layers of copper wire around the first one. This wire, though, can only withstand 2,500 times the atmospheric pressure. But protected by a plastic corset, a current pulse lasting only a fifth of a second suffices to create a 40 tesla magnetic field inside the coil. Together with the 50 Tesla of the inner coil, this adds up to the world record of more than 90 Tesla. Covered by a steel jacket, this double coil has a height of 55 centimeters and a diameter of 32 centimeters; thus, resembling a fairly large water bucket. For several weeks, the HZDR technicians worked on the coil which not only set the world record, but which will also permit many future studies of new materials in the record magnetic field.

For such experiments, researchers are flocking to Dresden not only from Regensburg, Garching, and Karlsruhe, but also from all over Europe. Even Japanese and US American scientists are already making reservations at the HZDR so that they can analyze their materials here. And since today the existing five rooms equipped with similar coils can no longer handle the crowds of researchers, an additional six of these “pulse cells” will be built by 2015. Magnetic-field research at the HZDR actually continues to expand even after the world record.

Source: Helmholtz-Zentrum Dresden-Rossendorf

 

Scientists from Harvard University trained pigeons to fly through an artificial forest with a tiny camera attached to their heads, literally giving a birds-eye view. "Attaching the camera to the bird as well as filming them from either side means we can reconstruct both what the bird sees and how it moves," says Dr. Huai-Ti Lin, a lead researcher for this work who has special insight into flying as he is a remote control airplane pilot himself.

The pigeons were fitted with a tiny head-camera before they flew through the artificial forest.

The methods pigeons use to navigate through difficult environments could be used as a model for auto-pilot technology. Pigeons, with >300 degree panoramic vision, are well suited to this task because this wrap-round vision allows them to assess obstacles on either side. They can also stabilise their vision and switch rapidly between views using what is called a "head saccade", a small rapid movement of the head.

The researchers also showed that the birds have other skills that would be important for auto-piloted machines, for example they tend to choose the straightest routes. "This is a very efficient way of getting through the forest, because the birds have to do less turns and therefore use less energy but also because they reach the other side quicker," says Dr Lin. "Another interesting finding is that pigeons seems to exit the forest heading in exactly the same direction as when they entered, in spite of all the twist and turns they made in the forest."

This image shows a pigeon, fitted with a camera, about to fly through the artificial forest that can be seen in the background.

When using a robot or an unmanned air-craft it would be invaluable to simply provide it with the coordinates of the destination without having to give it detailed information of all the obstacles it might meet on the way. "If we could develop the technology to follow the same methods as birds we could let the robot get on with it without giving it any more input," says Dr. Lin.

Source: EurekAlert

 

The findings show that the biomaterial could possibly be used in the future detection of toxins, explosives, pollutants, and medicines.

Detection devices have superior sensitivity when the sensor itself can be packaged at high density. Certain proteins that are found in the membranes of cells can act as sensors. However, the density with which cellular membranes can be packed in a sensor of a defined volume can limit the application. In this study, use was made of a particular form of matter, referred to as a liquid crystal or mesophase, that behaved as a densely packed mimic for cellular membranes.

Certain naturally occurring lipids or fats, when combined with water spontaneously form liquid crystals. One of these lipids called monoolein is a product of fat digestion. The liquid crystalline cubic phase that monoolein forms, when wet, has the lipid arranged as a bilayer just two molecules thick that is bathed on either side by water. This hydrated bilayer resembles the membrane that surrounds the cells in living organisms. The cubic phase is particularly notable as a liquid crystal in the extraordinary density with which it packages the membrane and the enormous surface area that it has. Thus, for example, a mere thimbleful of the cubic phase has enough surface area to cover a football field.

The research conducted by Trinity’s Professor of Membrane Structural and Functional Biology, Martin Caffrey and Research Associate Dr Dianfan Li in the School of Medicine and School of Biochemistry & Immunology used the cubic phase; but the cubic phase made from hydrated fat alone was useless. It needed to have a membrane protein sensor incorporated into it and the protein needed to be active. The test sensor used in the research was a membrane protein, referred to as DgkA. DgkA is an enzyme that interconverts the fatty components of natural cellular membranes. The enzyme was produced in E. coli bacteria, using recombinant DNA technology, as an inactive or dead ‘scrambled egg’ type of insoluble aggregate. ‘Life’ was breathed back into the enzyme by dissolving the aggregated protein in a soapy solution and inserting it into the membrane of the cubic phase. In this new and quite artificial environment the researchers showed that the protein had regained its original native enzyme activity and that it could behave as a model sensor.

The research sets the stage for the exploitation of this most extraordinary of biomaterials. These include its use in high density, high sensitivity biosensors for the detection of biological molecules such as hormones, proteins, carbohydrates, and lipids, as well as toxins, explosives, pollutants, and drugs.

Source: Trinity College Dublin

 

Scientists from the Universities of Sheffield and Cambridge have published research on manufacturing ultra-cheap solar energy panels for large-scale domestic and industrial use. The idea is to use high-volume printing to produce nanoscale films of polymer solar cells --- cells more than a 1,000 times thinner than the width of a human hair.

photo diamond light source solar cling film story art

Now we've heard of thin-film and other solar advancements before. But the existing technology, with polymer solar cells, is only 7-8% efficient. The next step is to develop cells that are 10% efficient, or more, the scientists say.

The researchers used the ISIS Neutron Source and Diamond Light Source at STFC Rutherford Appleton Laboratory in Oxfordshire to study the crystallinity of the material and examine its composition profile.

According to Physorg.com:

"The study showed that when complex mixtures of molecules in solution are spread onto a surface, like varnishing a table-top, the different molecules separate to the top and bottom of the layer in a way that maximises the efficiency of the resulting solar cell."

Robert Dalgliesh, one of the ISIS scientists involved in the work, said, "... Using neutron beams at ISIS and Diamond's bright X-rays, we were able to probe the internal structure and properties of the solar cell materials non-destructively. By studying the layers in the materials which convert sunlight into electricity, we are learning how different processing steps change the overall efficiency and affect the overall polymer solar cell performance."

This study, published in the journal Advanced Energy Materials, used a photovoltaic blend of materials called PCDTBT: PCBM, and based on the Nobel-prize-winning, 1996 chemistry work of professors Richard Smalley and Harry Kroto.

The research was funded with a grant from the Engineering and Physical Sciences Research Council, and a new grant to carry out further studies has been awarded. The ISIS and Diamond Light Source devices are affiliated with the Science & Technology Facilities Council.

Source: TreeHugger

 

Now, the Whitesides group at Harvard University has developed a force sensor for a microelectromechanical system (MEMS) using paper as the structural material [Whitesides et al., Lab Chip(2011) doi: 10.1039/c1lc20161a].

MEMS devices are becoming increasingly common in research, in industrial settings and in medical diagnostics. Several companies have now developed MEMS for a wide range of applications: digital micromirror devices (DMD, Texas Instruments), accelerometers for firing vehicle airbags (Analog Devices and Motorola), and pressure/?ow sensors for industrial uses (Honeywell). However, while such devices are based on semiconductor materials, such as silicon, they will remain expensive and require complex manufacturing facilities and clean rooms for their construction.

Photograph of an array of four devices. Image courtesy of Xinyu Liu, Whitesides. Reproduced from Lab Chip (2011) doi: 10.1039/c1lc20161a by permission of The Royal Society of Chemistry.

Whitesides and colleagues hope to circumvent such obstacles by finding inexpensive alternatives to silicon and its ilk and precluding the need for complex and costly fabrication processes. As such, they have now developed a prototypical MEMS device; a paper-based piezoresistive force sensor, demonstrating that a readily available and easy to prepare material can be used to build useful devices, albeit with perhaps poorer performance than conventional MEMS. The same approach has also been used to develop a paper-based weighing balance.

The group emphasizes that the force sensor is simple to construct, taking less than an hour with no special facilities or equipment; a paper cutter and painting knife are all that are needed. Material costs for each device are of the order of a few cents. When asked about the novelty and utility of this work, Whitesides remarked to Materials Today that, "Sometimes things that obviously can't work have a mind of their own and work anyway."

The team has shown that the force sensor can measure the properties of a soft material with moderate, but useful, performance compared to conventional MEMS, giving a resolution of 120 micronewtons and a 16 millinewton measurement range. The paper-based balance can measure up to 15 grams and has a resolution of 0.39 grams.

These low-cost, portable and disposable paper-based MEMS devices could be used as single-use sensors in analytical applications, for instance in the mechanical characterization of tissues in medical diagnostics and in food viscosity measurements. The researchers add that in contrast to silicon-based MEMS, a paper-based device might be too sensitive to high temperatures, atmospheric components , such as water vapor, ozone, peroxides, etc. However, in some contexts such sensitivities might also be exploited for other applications of the device, such as humidity sensors or an ad hoc chemical detector for emergencies.

Source: Materials Today

 

The research adds an important link to discoveries that have enabled scientists to gain a deeper understanding of how cells translate genetic information into the proteins and processes of life. The findings, published in the July 3 advance online issue of the journal Nature, were reported by a research team led by Yuichiro Takagi, Ph.D., assistant professor of biochemistry and molecular biology at Indiana University School of Medicine.

The fundamental operations of all cells are controlled by the genetic information – the genes –stored in each cell's DNA, a long double-stranded chain. Information copied from sections of the DNA – through a process called transcription – leads to synthesis of messenger RNA, eventually enabling the production of proteins necessary for cellular function. Transcription is undertaken by the enzyme called RNA polymerase II.

As cellular operations proceed, signals are sent to the DNA asking that some genes be activated and others be shut down. The Mediator transcription regulator accepts and interprets those instructions, telling RNA polymerase II where and when to begin the transcription process.

 Researchers decipher protein structure of key molecule in DNA transcription system

Mediator is a gigantic molecular machine composed of 25 proteins organized into three modules known as the head, the middle, and the tail. Using X-ray crystallography, the Takagi team was able to describe in detail the structure of the Mediator Head module, the most important for interactions with RNA polymerase II.

"It's turned out to be extremely novel, revealing how a molecular machine is built from multiple proteins," said Takagi.

"As a molecular machine, the Mediator head module needs to have elements of both stability and flexibility in order to accommodate numerous interactions. A portion of the head we named the neck domain provides the stability by arranging the five proteins in a polymer-like structure," he said.

"We call it the alpha helical bundle," said Dr. Takagi. "People have seen structures of alpha helical bundles before but not coming from five different proteins."

"This is a completely noble structure," he said.

One immediate benefit of the research will be to provide detailed mapping of previously known mutations that affect the regulation of the transcription process, he said.

The ability to solve such complex structures will be important because multi-protein complexes such as Mediator will most likely become a new generation of drug targets for treatment of disease, he said.

Previously, the structure of RNA polymerase II was determined by Roger Kornberg of Stanford University, with whom Dr. Takagi worked prior to coming to IU School of Medicine. Kornberg received the Nobel Prize in 2006 for his discoveries. The researchers who described the structure of the ribosome, the protein production machine, were awarded the Nobel Prize in 2009. The structure of the entire Mediator has yet to be described, and thus remains the one of grand challenges in structure biology. Dr. Takagi's work on the Mediator head module structure represents a major step towards a structure determination of the entire Mediator.

Source: PhysOrg

 

His experiments using the fluorinated polymer as a surface coating for pots and pans helped usher in a revolution in non-stick cookware. Today, NYU-Poly Assistant Professor of Chemical and Biological Sciences Jin Montclare is taking the research theme in a new direction, investigating fluorinated proteins -- a unique class of proteins that may have a wide range of applications from industrial detergents to medical therapeutics.

In a paper published in the current issue of ChemBioChem, Montclare and Peter Baker, who just received his doctoral degree from NYU-Poly, detail their success in creating proteins that are considerably more stable and less prone to denaturation than their natural counterparts. These qualities enable them to retain both their structure and function under high temperatures in which other proteins would simply break down.

Inspired by teflon, researchers create super durable proteins

Fluorinated amino acids (p-fluorophenylalnine highlighted in the interface) help stabilize Teflon-like proteins against heat inactivation, allowing them to function more robustly, even at elevated temperatures.

Inspired by the ability of fluorinated polymers like Teflon to stabilize surfaces, Montclare and Baker set their sights on developing a process that would allow them to reinforce the interface of proteins, rendering them more resistant to degradation.

“One of the main challenges of proteins—whether they’re in the body or in the lab—is that they are naturally created to function under specific conditions, and to break down under others,” Montclare explained. “A stable protein that was still active and functional under a variety of conditions would open up an extraordinary range of potential for scientists and product developers.”

Through a trick of genetic engineering, the scientists were able to coax a strain of bacteria into taking up amino acids—the building blocks of protein—that were chemically altered by the addition of fluorine. “Nature doesn’t make fluorinated amino acids, but these experiments show that we can create them,” said Montclare. The result was a "fluorinated" protein that can withstand temperatures up to 140 degrees Fahrenheit with no compromise in activity or function.

Next up for Montclare and Baker are experiments to test the limits of their success in creating fluorinated or Teflon-like proteins. They’re hoping that this type of effect can be achieved with a wide range of proteins, especially those used in medicine including some therapeutic cancer drugs. The stable proteins may also some day act as prophylactics to combat exposure to neurotoxic agents (including warfare agents)–something that is of interest to the Department of Defense. The scientists hope to improve the proteins’durability and decrease the need for precise storage conditions, which often include refrigeration to prevent breakdown.

Source: PhysOrg

 

In the long term the technology could be used by customers to design many different products themselves -- tailor-made to their needs and preferences.

Using new digital technology the printer allows you to create your own designs on a computer and reproduce them physically in three dimensional form in chocolate.

The project is funded as part of the Research Council UK Cross-Research Council Programme -- Digital Economy and is managed by the Engineering and Physical Sciences Research Council (EPSRC) on behalf of ESRC, AHRC and MRC. It is being led by the University of Exeter in collaboration with the University of Brunel and software developer Delcam.

Chocolate printer. (Credit: Image courtesy of EPSRC)

3-D printing is a technology where a three dimensional object is created by building up successive layers of material. The technology is already used in industry to produce plastic and metal products but this is the first time the principles have been applied to chocolate.

The research has presented many challenges. Chocolate is not an easy material to work with because it requires accurate heating and cooling cycles. These variables then have to be integrated with the correct flow rates for the 3-D printing process. Researchers overcame these difficulties with the development of new temperature and heating control systems.

Research leader Dr Liang Hao, at the University of Exeter, said: "What makes this technology special is that users will be able to design and make their own products. In the long term it could be developed to help consumers custom- design many products from different materials but we've started with chocolate as it is readily available, low cost and non-hazardous. There is also no wastage as any unused or spoiled material can be eaten of course! From reproducing the shape of a child's favourite toy to a friend's face, the possibilities are endless and only limited by our creativity."

A consumer- friendly interface to design the chocolate objects is also in development. Researchers hope that an online retail business will host a website for users to upload their chocolate designs for 3-D printing and delivery.

Designs need not start from scratch, the web- based utility will also allow users to see designs created by others to modify for their own use.

Dr Hao added: "In future this kind of technology will allow people to produce and design many other products such as jewellery or household goods. Eventually we may see many mass produced products replaced by unique designs created by the customer."

EPSRC Chief Executive Professor Dave Delpy said: "This is an imaginative application of two developing technologies and a good example of how creative research can be applied to create new manufacturing and retail ideas. By combining developments in engineering with the commercial potential of the digital economy we can see a glimpse into the future of new markets -- creating new jobs and, in this case, sweet business opportunities."

Source: ScienceDaily

 

Today's silicon-based microprocessor chips rely on electric currents, or moving electrons, that generate a lot of waste heat. But microprocessors employing nanometer-sized bar magnets -- like tiny refrigerator magnets -- for memory, logic and switching operations theoretically would require no moving electrons.

Such chips would dissipate only 18 millielectron volts of energy per operation at room temperature, the minimum allowed by the second law of thermodynamics and called the Landauer limit. That's 1 million times less energy per operation than consumed by today's computers.

"Today, computers run on electricity; by moving electrons around a circuit, you can process information," said Brian Lambson, a UC Berkeley graduate student in the Department of Electrical Engineering and Computer Sciences. "A magnetic computer, on the other hand, doesn't involve any moving electrons. You store and process information using magnets, and if you make these magnets really small, you can basically pack them very close together so that they interact with one another. This is how we are able to do computations, have memory and conduct all the functions of a computer."

Lambson is working with Jeffrey Bokor, UC Berkeley professor of electrical engineering and computer sciences, to develop magnetic computers.

"In principle, one could, I think, build real circuits that would operate right at the Landauer limit," said Bokor, who is a codirector of the Center for Energy Efficient Electronics Science (E3S), a Science and Technology Center founded last year with a $25 million grant from the National Science Foundation. "Even if we could get within one order of magnitude, a factor of 10, of the Landauer limit, it would represent a huge reduction in energy consumption for electronics. It would be absolutely revolutionary."

One of the center's goals is to build computers that operate at the Landauer limit.

Lambson, Bokor and UC Berkeley graduate student David Carlton published a paper about their analysis online in the journal Physical Review Letters.

Fifty years ago, Rolf Landauer used newly developed information theory to calculate the minimum energy a logical operation, such as an AND or OR operation, would dissipate given the limitation imposed by the second law of thermodynamics. (In a standard logic gate with two inputs and one output, an AND operation produces an output when it has two positive inputs, while an OR operation produces an output when one or both inputs are positive.) That law states that an irreversible process -- a logical operation or the erasure of a bit of information -- dissipates energy that cannot be recovered. In other words, the entropy of any closed system cannot decrease.

In today's transistors and microprocessors, this limit is far below other energy losses that generate heat, primarily through the electrical resistance of moving electrons. However, researchers such as Bokor are trying to develop computers that don't rely on moving electrons, and thus could approach the Landauer limit. Lambson decided to theoretically and experimentally test the limiting energy efficiency of a simple magnetic logic circuit and magnetic memory.

The nanomagnets that Bokor, Lambson and his lab use to build magnetic memory and logic devices are about 100 nanometers wide and about 200 nanometers long. Because they have the same north-south polarity as a bar magnet, the up-or-down orientation of the pole can be used to represent the 0 and 1 of binary computer memory. In addition, when multiple nanomagnets are brought together, their north and south poles interact via dipole-dipole forces to exhibit transistor behavior, allowing simple logic operations.

"The magnets themselves are the built-in memory," Lambson said. "The real challenge is getting the wires and transistors working."

Lambson showed through calculations and computer simulations that a simple memory operation -- erasing a magnetic bit, an operation often called "restore to one" -- can be conducted with an energy dissipation very close, if not identical to, the Landauer limit.

He subsequently analyzed a simple magnetic logical operation. The first successful demonstration of a logical operation using magnetic nanoparticles was achieved by researchers at the University of Notre Dame in 2006. In that case, they built a three-input majority logic gate using 16 coupled nanomagnets. Lambson calculated that a computation with such a circuit would also dissipate energy at the Landauer limit.

Because the Landauer limit is proportional to temperature, circuits cooled to low temperatures would be even more efficient.

At the moment, electrical currents are used to generate a magnetic field to erase or flip the polarity of nanomagnets, which dissipates a lot of energy. Ideally, new materials will make electrical currents unnecessary, except perhaps for relaying information from one chip to another.

"Then you can start thinking about operating these circuits at the upper efficiency limits," Lambson said.

"We are working now with collaborators to figure out a way to put that energy in without using a magnetic field, which is very hard to do efficiently," Bokor said. "A multiferroic material, for example, may be able to control magnetism directly with a voltage rather than an external magnetic field."

Other obstacles remain as well. For example, as researchers push the power consumption down, devices become more susceptible to random fluctuations from thermal effects, stray electromagnetic fields and other kinds of noise.

"The magnetic technology we are working on looks very interesting for ultra low power uses," Bokor said. "We are trying to figure out how to make it more competitive in speed, performance and reliability. We need to guarantee that it gets the right answer every single time with a very, very, very high degree of reliability."

Source: Science Daily

 

Electron micrograph of H. pylori

It's widely recognized that asthma rates have increased significantly since the 1960's and continue to rise. With increases in asthma and other allergic diseases centered on industrialized nations, a recent hypothesis suggested that the disappearance of specific microorganisms that populate the human body due to modern hygiene practices might be to blame. Now researchers claim they have confirmed this hypothesis by proving that a certain gastric bacterium provides reliable protection against allergy-induced asthma.

The hygiene hypothesis states that modern hygiene practices and overuse of antibiotics have led to a lack of early childhood exposure to infectious agents, symbiotic microorganisms and parasites, which has suppressed the natural development of the body's immune system. Scientists from the University of Zurich and the University Medical Center of the Johannes Gutenberg University Mainz are now saying that the increase in asthma could be put down to the specific disappearance of the gastric bacterium Helicobacter pylori (H. pylori) from Western societies.

H. pylori is a bacterium that is resistant to gastric acid and it is estimated that it could currently infect around half of the world's population. While it can cause gastritis, gastric and duodenal ulcers, and stomach cancer under certain conditions, over 80 percent of individuals infected with the bacterium are asymptomatic. However, even if the patient doesn't show any symptoms, H. pylori is often killed off with antibiotics as a precaution.

For their study, the researchers infected mice with H. pylori bacteria at different stages of their development. They found that mice that were infected at just a few days old developed immunological tolerance to the bacterium and reacted insignificantly or not at all to strong, asthma-inducing allergens. Mice that were not infected until they had reached adulthood, however, had a much weaker defense.

"Early infection impairs the maturation of the dendritic cells and triggers the accumulation of regulatory T-cells that are crucial for the suppression of asthma," explains Anne Müller, a professor of molecular cancer research at the University of Zurich.

The researchers also found that if the regulatory T-cells were transferred from infected mice to uninfected mice, they too enjoyed effective protection against allergy-induced asthma. Additionally, mice that had been infected early lost their resistance to asthma-inducing allergens in H. pylori was killed off in them using antibiotics.

According to lung and allergy specialist Christian Taube, a senior physician at III. Medical Clinic of the Johannes Gutenberg University Mainz, the new results that are published in the Journal of Clinical Investigation confirm the hypothesis that the increase in allergic asthma in industrial nations is linked to the widespread use of antibiotics and the subsequent disappearance of micro-organisms that permanently populate the human body.

"The study of these fundamental mechanisms is extremely important for us to understand asthma and be able to develop preventative and therapeutic strategies later on," he said.

Source: GizMag

 
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14/01/2018 @ 16:07:36
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