Copper on the brain at rest

 

Mon, 12/01/2014 - 8:59am Lynn Yarris, Lawrence Berkeley National Laboratory Two-photon imaging of CF3 in cultured dissociated hippocampal neurons shows how the addition of the BCS chelator shrinks the presence of labile copper pools.In recent years it has been established that copper plays an essential role in the health of the human brain. Improper copper oxidation has been linked to several neurological disorders including Alzheimer’s, Parkinson’s, Menkes’ and Wilson’s. Copper has also been identified as a critical ingredient in the enzymes that activate the brain’s neurotransmitters in response to stimuli. Now a new study by researchers with the U.S. Dept. of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has shown that proper copper levels are also essential to the health of the brain at rest. “Using new molecular imaging techniques, we’ve identified copper as a dynamic modulator of spontaneous activity of developing neural circuits, which is the baseline activity of neurons without active stimuli, kind of like when you sleep or daydream, that allows circuits to rest and adapt,” says Chris Chang, a faculty chemist with Berkeley Lab’s Chemical Sciences Div. who led this study. “Traditionally, copper has been regarded as a static metabolic cofactor that must be buried within enzymes to protect against the generation of reactive oxygen species and subsequent free radical damage. We’ve shown that dynamic and loosely bound pools of copper can also modulate neural activity and are essential for the normal development of synapses and circuits.” Chang, who also holds appointments with the Univ. of California (UC) Berkeley’s Chemistry Dept. and the Howard Hughes Medical Institute (HHMI), is the corresponding author of a paper that describes this study in the Proceedings of the National Academy of Sciences (PNAS). Co-authors are Sheel Dodani, Alana Firl, Jefferson Chan, Christine Nam, Allegra Aron, Carl Onak, Karla Ramos-Torres, Jaeho Paek, Corey Webster and Marla Feller. Although the human brain accounts for only two-percent of total body mass, it consumes 20% of the oxygen taken in through respiration. This high demand for oxygen and oxidative metabolism has resulted in the brain harboring the body’s highest levels of copper, as well as iron and zinc. Over the past few years, Chang and his research group at UC Berkeley have developed a series of fluorescent probes for molecular imaging of copper in the brain. “A lack of methods for monitoring dynamic changes in copper in whole living organisms has made it difficult to determine the complex relationships between copper status and various stages of health and disease,” Chang said. “We’ve been designing fluorescent probes that can map the movement of copper in live cells, tissue or even model organisms, such as mice and zebra fish.” For this latest study, Chang and his group developed a fluorescent probe called Copper Fluor-3 (CF3) that can be used for one- and two-photon imaging of copper ions. This new probe allowed them to explore the potential contributions to cell signaling of loosely bound forms of copper in hippocampal neurons and retinal tissue. “CF3 is a more hydrophilic probe compared to others we have made, so it gives more even staining and is suitable for both cells and tissue,” Chang says. “It allows us to utilize both confocal and two-photon imaging methods when we use it along with a matching control dye (Ctrl-CF3) that lacks sensitivity to copper.” With the combination of CF3 and Ctrl-CF3, Chang and his group showed that neurons and neural tissue maintain stores of loosely bound copper that can be attenuated by chelation to create what is called a “labile copper pool.” Targeted disruption of these labile copper pools by acute chelation or genetic knockdown of the copper ion channel known as CTR1 (for copper transporter 1) alters spontaneous neural activity in developing hippocampal and retinal circuits. “We demonstrated that the addition of the copper chelator bathocuproine disulfonate (BCS) modulates copper signaling which translates into modulation of neural activity,” Chang says. “Acute copper chelation as a result of additional BCS in dissociated hippocampal cultures and intact developing retinal tissue removed the copper which resulted in too much spontaneous activity.” The results of this study suggest that the mismanagement of copper in the brain that has been linked to Wilson’s, Alzheimer’s and other neurological disorders can also contribute to misregulation of signaling in cell−to-cell communications. “Our results hold therapeutic implications in that whether a patient needs copper supplements or copper chelators depends on how much copper is present and where in the brain it is located,” Chang says. “These findings also highlight the continuing need to develop molecular imaging probes as pilot screening tools to help uncover unique and unexplored metal biology in living systems.” Source: Lawrence Berkeley National Laboratory

Best Compact Cameras 2014 - republishing -

 

Which are the best compact cameras of the year? Here's our pick of the Best Compact Cameras Olympus TG 1 While there’s no arguing that the compact camera market is coming under increasing pressure for both the smartphone and CSC market, there’s still a lot to be said for having a dedicated camera with a fixed lens that you can easily take everywhere.The good news is that there’s still a broad range of attractive compacts cameras on the market, and of a wide range of varieties to suit every need.                                 Here are some of the best compact cameras currently on the market. Sony RX100 III Sony RX100 III Street price: £699 If you’re looking for the very best in compact cameras, Sony’s RX100 series has long been the place to turn to. The RX100 III represents the third in the series, and is arguably the best yet. It features a pop-up electronic viewfinder, vari-angle LCD screen and Sony’s impressive Bionz processor. It also retains the 1in sensor that has made the range so popular, delivering some excellent images along the way. At around the seven hundred pound mark the RX100 III is certainly not cheap, although it’s one of the most complete compacts going. Best Compact Camera for: The very best in pocketable imaging Read our Sony Cybershot RX100 III review Panasonic Lumix TZ60 Panasonic Lumix TZ60 Street price: £330 If you’re in the market for a travel compact, the chances are that you’re aware of, or have been pointed in the direction of, Panasonic’s TZ range. The TZ60 is the latest in a long line of impressive travel compacts and boasts all of the range’s hallmarks. These include a large 30x optical zoom, HD video capture and a large LCD screen. The model now also benefits from Raw capture as well JPEG capture, as as a result you could argue its the most complete travel compact to date. Best Compact Camera for: Those wanting excellent image quality in a body suitable for long travels Read our Panasonic Lumix TZ60 review Olympus TG-3 Olympus TG-3 Street price: £340 There are a wide range of waterproof and generally lifeproof cameras on the market, with Olympus certainly producing more than its fair share. Sitting at the top of its tough compact tree is the TG-3 – a model that’s so much more than simply a tough compact. The camera features an impressive 5fps burst mode, excellent battery life and will stand up to all life can throw at it. Best Compact Camera for: Putting through its paces on the beach or the slopes Read our Olympus TG-3 review Sony RX1 Street price: £1850 Sony RX1 Despite being priced well outside the reach of most people’s wallets, the Sony RX1 is nonetheless a serious prospect for the well-heeled enthusiast. Where the RX1 is really excels is with regards to image quality, as Sony have managed to cram a huge full-frame sensor in to its relatively compact body. The model also features a fixed 35mm Carl Zeiss lens that’s as sharp as a pin, along with a wide range of other high-end features. If you’re looking for the very best in compact imaging and have a large budget, the RX1 is the one for you. Best Compact Camera for: The very best in image quality Read our full review of the Sony RX1

Could electric clay be the world's next wonder-material?

 

A fan of conductive clay? (Photo: Drexel University) Image Gallery (8 images) Researchers at Drexel University have hit upon a conductive clay which they claim is an "exceptionally viable candidate" to one day replace the electrode materials used in batteries and supercapacitors. Sure, another day another super material, but MXene, as it's called, does boast some rather intriguing properties. Why's it good, then? You don't beat about the bush, do you? Very well. The three main properties of MXene that caught our eye are: 1. It's hydrophilic. That means, unlike graphene, it loves water. And that's good news because it means... 2. It's very malleable. You can mold it into complicated forms, or roll or press it very flat – both of which are potentially very handy for a material with conductivity supposedly is up there with metals. 3. The material has a very healthy capacitance of 900 F/cm3 – and that's basically at the first attempt. The team has done nothing to improve that performance. But perhaps more intriguing still is the claim that MXene lost no capacitance after more than 10,000 charge cycles. How do you say MXene? The researchers pronounce it mex-een. And this is a new material? Yes and no. MXene was first discovered in 2011. It's a material composed of two-dimensional titanium carbide derived from MAX phases. What's new is the researchers' ability to make it as a clay, a form which is not only useful, but much quicker and safer than the old method, and using readily-available materials. It used to take the researchers a day to make a MXene electrode. Now they can do it in 15 minutes. What does it look like under an electron microscope? This: So we can expect clay batteries from tomorrow, then? No. This is absurdly early stages for the material. And so far we've only read the press release, which tend not to emphasize any shortcomings or problems that may exist. We'll track down a copy of the paper and will update this article if we spot any major caveats. All of that said, the researchers do seem rather excited. "We’re talking about quite a special lump of clay here," said doctoral student Maria Lukatskaya.   Source: Drexel University

Thermographic camera

 

Image of a small dog taken in mid-infrared ("thermal") light (false-color) A thermographic camera (also called an infrared camera or thermal imaging camera) is a device that forms an image using infrared radiation, similar to a common camera that forms an image using visible light. Instead of the 450–750 nanometer range of the visible light camera, infrared cameras operate in wavelengths as long as 14,000 nm (14 µm). Their use is called thermography.   History Precursors Infrared was discovered by Sir William Herschel as a form of radiation beyond red light. These "infrared rays" (infra is the Latin prefix for "below") were used mainly for thermal measurement. There are four basic laws of IR radiation: Kirchhoff's law of thermal radiation, Stefan-Boltzmann law, Planck’s law, and Wien’s displacement law. The development of detectors’ was mainly focused on the use of thermometer and bolometers until World War I. Leopoldo Nobili fabricated the first thermocouple in 1829, which paved the way for Macedonio Melloni to show that a person 10 meters away could be detected with his multielement thermopile. The bolometer was invented in 1878 by Langley. It had the capability to detect radiation from a cow from 400 meters away, and was sensitive to differences in temperature of one hundred thousandth of a degree Celsius. The first advanced application of IR technology in the civil section may have been a device to detect the presence of icebergs and steamships using a mirror and thermopile, patented in 1913.This was soon outdone by the first true IR iceberg detector, which did not use thermopiles, patented in 1914 by R.D. Parker. This was followed up by G.A. Barker’s proposal to use the IR system to detect forest fires in 1934. The technique was not truly industrialized until it was used in the analysis of heating uniformity in hot steel strips in 1935. First thermographic camera In 1929, Hungarian physicist Kálmán Tihanyi invented the infrared-sensitive (night vision) electronic television camera for anti-aircraft defense in Britain.[7] The first conventional thermographic cameras began with the development of the first infrared line scanner. This was created by the US military and Texas Instruments in 1947[8] and took one hour to produce a single image. While several approaches were investigated to improve the speed and accuracy of the technology, one of the most crucial factors that needed to be considered dealt with scanning an image, which the AGA company was able to commercialize using a cooled photoconductor. This work was further developed at the Royal Signals and Radar Establishment in the UK when they discovered mercury cadmium telluride could be used as a conductor that required much less cooling. Honeywell in the United States also developed arrays of detectors which could cool at a lower temperature, but they scanned mechanically. This method had several disadvantages which could be overcome using an electronically scanning system. In 1969 Michael Francis Tompsett at English Electric Valve Company in the UK patented a camera which scanned pyro-electronically and which reached a high level of performance after several other breakthroughs throughout the 1970s. Tompsett also proposed an idea for solid-state thermal-imaging arrays, which eventually led to modern hydridized single-crystal-slice imaging devices. Smart sensors One of the most important areas of development for security systems was for the ability to intelligently evaluate a signal, as well as warning for a threats’ presence. Under the encouragement of the United States Strategic Defense Initiative, "smart sensors" began to appear. These are sensors that could integrate sensing, signal extraction, processing, and comprehension. There are two main types of Smart Sensors. One, similar to what are called "vision chips" when used in the visible range, allow for preprocessing using Smart Sensing techniques due to the increase in growth of integrated microcircuitry. The other technology is more oriented to a specific use and fulfills its preprocessing goal through its design and structure. Towards the end of the 1990s the use of infrared was moving towards civil use. There was a dramatic lowering of costs for uncooled arrays, which along with the large increase in developments lead to a dual way use market between civil and military. These uses include environmental control, building/art analysis, medical functional diagnostics, and car guidance and collision avoidance systems. Theory of operation A thermal image showing temperature variation in a hot air balloon. Infrared energy is just one part of the electromagnetic spectrum, which encompasses radiation from gamma rays, x-rays, ultra violet, a thin region of visible light, infrared, terahertz waves, microwaves, and radio waves. These are all related and differentiated in the length of their wave (wavelength). All objects emit a certain amount of black body radiation as a function of their temperatures. Generally speaking, the higher an object's temperature, the more infrared radiation is emitted as black-body radiation. A special camera can detect this radiation in a way similar to the way an ordinary camera detects visible light. It works even in total darkness because ambient light level does not matter. This makes it useful for rescue operations in smoke-filled buildings and underground. In use Thermographic image of a ringtailed lemur Images from infrared cameras tend to have a single color channel because the cameras generally use an image sensor that does not distinguish different wavelengths of infrared radiation. Color image sensors require a complex construction to differentiate wavelengths, and color has less meaning outside of the normal visible spectrum because the differing wavelengths do not map uniformly into the system of color vision used by humans. Sometimes these monochromatic images are displayed in pseudo-color, where changes in color are used rather than changes in intensity to display changes in the signal. This is useful because although humans have much greater dynamic range in intensity detection than color overall, the ability to see fine intensity differences in bright areas is fairly limited. This technique is called density slicing. For use in temperature measurement the brightest (warmest) parts of the image are customarily colored white, intermediate temperatures reds and yellows, and the dimmest (coolest) parts black. A scale should be shown next to a false color image to relate colors to temperatures. Their resolution is considerably lower than that of optical cameras, mostly only 160 x 120 or 320 x 240 pixels, although more expensive cameras can achieve a resolution of 1280 x 1024 pixels. Thermographic cameras are much more expensive than their visible-spectrum counterparts, though low-performance add-on thermal cameras for smartphones became available for hundreds of dollars in 2014. Higher-end models are often deemed as dual-use and export-restricted, particularly if the resolution is 640 x 480 or greater, unless the refresh rate is 9 Hz or less. The export of thermal cameras is regulated by International Traffic in Arms Regulations, or ITAR. All FLIR VOx microbolometers are restricted to 7.5 Hz for export outside of the US. In uncooled detectors the temperature differences at the sensor pixels are minute; a 1 °C difference at the scene induces just a 0.03 °C difference at the sensor. The pixel response time is also fairly slow, at the range of tens of milliseconds. Thermography finds many other uses. For example, firefighters use it to see through smoke, find people, and localize hotspots of fires. With thermal imaging, power line maintenance technicians locate overheating joints and parts, a telltale sign of their failure, to eliminate potential hazards. Where thermal insulation becomes faulty, building construction technicians can see heat leaks to improve the efficiencies of cooling or heating air-conditioning. Thermal imaging cameras are also installed in some luxury cars to aid the driver, the first being the 2000 Cadillac DeVille. Some physiological activities, particularly responses such as fever, in human beings and other warm-blooded animals can also be monitored with thermographic imaging. Cooled infrared cameras can be found at major astronomy research telescopes, even those that are not infrared telescopes. source : Wikipedia

New electrolyte for construction of magnesium-sulfur batteries

 

Electron microscopy of the cathode composite. The Helmholtz Institute Ulm (HIU) established by Karlsruhe Institute of Technology (KIT) is pushing research relating to batteries of the next and next-but-one generations: A research team has now developed an electrolyte that may be used for the construction of magnesium-sulfur battery cells. With magnesium, higher storage densities could be achieved than with lithium. Moreover, magnesium is abundant in nature, it is non-toxic, and does not degrade in air. The new electrolyte is now presented in the journal Advanced Energy Materials. In many electrical devices, lithium-ion and metal-hydride batteries are applied for energy storage. Scientists are also studying alternatives to these established battery systems in order to enhance the safety, cost efficiency, sustainability, and performance of future devices. It is their objective to replace lithium by other elements. For this purpose, all battery components have to be newly developed and understanding of electrochemical processes is required. Magnesium-based battery cells are presently considered an attractive option to replace lithium in batteries. In principle, magnesium allows higher storage densities to be reached than lithium. Other advantages of magnesium are its high abundance in nature, its non-toxicity, and its low degradation in air in contrast to lithium. So far, progress achieved in this area has been limited. For the design of magnesium batteries of high storage capacity and power density, suitable electrolytes are needed that can be easily to produced, that are stable, and can be used in high concentrations in different solvents. At the HIU, a research team headed by Maximilian Fichtner and Zhirong Zhao-Karger has now presented a new promising electrolyte, which might allow for the development of an entirely new generation of batteries. The new electrolyte is characterized by a number of promising properties. It possesses an unprecedented electrochemical stability window and a very high efficiency. In addition, the electrolyte can be used in various solvents and at high concentrations. Moreover, the electrolyte is chemically compatible with a sulfur cathode, which can be discharged at a voltage close to the theoretical value. Another advantage is the very simple production of the electrolyte. "Two commercially available standard chemicals, a magnesium amide and aluminium chloride, are applied. They are added to the solvent desired and subjected to stirring. This simple mixture can then be used directly as an electrolyte in the battery.," Maximilian Fichtner says. Story Source: The above story is based on materials provided by Karlsruhe Institute of Technology. Note: Materials may be edited for content and length. Journal Reference: Zhirong Zhao-Karger, Xiangyu Zhao, Di Wang, Thomas Diemant, R. Jürgen Behm, Maximilian Fichtner. Performance Improvement of Magnesium Sulfur Batteries with Modified Non-Nucleophilic Electrolytes. Advanced Energy Materials, 2014; DOI: 10.1002/aenm.201401155

Scanning tunneling microscopy: Computer simulations sharpen insights into molecules

 

Simulations of different types of scanning probe microscopy with atomic-scale sensors: Simulated atomic force microscopy image (left), simulated scanning tunnelling microscopy image (centre), simulation of an inelastic electron tunnelling spectroscopy image (right). The resolution of scanning tunnelling microscopes can be improved dramatically by attaching small molecules or atoms to their tip. The resulting images were the first to show the geometric structure of molecules and have generated a lot of interest among scientists over the last few years. Scientists from Forschungszentrum Jülich and the Academy of Sciences of the Czech Republic in Prague have now used computer simulations to gain deeper insights into the physics of these new imaging techniques. One of these techniques was presented in the journal Science by American scientists this spring. The results have now been published in the journal Physical Review Letters. "A comparison between the experimental results and our simulations shows excellent agreement and that, therefore, our theoretical model is able to explain the mechanism behind the microscopic images in this family of techniques," says Prof. Tautz from Forschungszentrum Jülich. "This comparison is essential for analysing the images." Together with his colleagues from the Peter Grünberg Institute (PGI-3), in 2008 Tautz introduced the method of attaching single molecules -- initially hydrogen molecules, later molecules such as carbon monoxide -- to the tip of a scanning tunnelling microscope and using them as extremely sensitive measuring probes. The scientific community responded with great interest to this method, and the technique has since been continuously refined. It enables scanning tunnelling microscopes to be used as a kind of atomic force microscope that is able to image the geometric structure of molecules with unprecedented accuracy. "The valence charge clouds of complex organic molecules often spread over the entire molecule, thus concealing its atomic structure," says Tautz. Flexibly bound molecules at the microscope tip can be utilized as tailor-made sensors and signal transducers that are able to make the atomic structure visible nevertheless. In the last few years, such atomic sensors have also proven useful for work with atomic force microscopes. Then, in May 2014, scientists from the University of California, Irvine, showed for the first time that these sensors can also be used to improve signals in a related imaging mode known as inelastic electron tunnelling spectroscopy. In this case, it is the vibration of the sensor molecule against the microscope tip that reacts sensitively to the surface potential of the scanned sample. "Our calculations show the effect of the electrostatic forces on the high-resolution AFM, STM, and IETS images," explains Dr. Pavel Jelínek from the Institute of Physics at the Academy of Sciences of the Czech Republic in Prague. "We believe that the results of this work are an important contribution to the use of inelastic electron tunnelling spectroscopy that will allow the technique to be used as an additional source of information in materials science and to derive additional parameters from the images." Story Source: The above story is based on materials provided by Forschungszentrum Juelich. Note: Materials may be edited for content and length. Journal References: Prokop Hapala, Ruslan Temirov, F. Stefan Tautz, Pavel Jelínek. Origin of High-Resolution IETS-STM Images of Organic Molecules with Functionalized Tips. Phys. Rev. Lett., 25 November 2014 DOI: 10.1103/PhysRevLett.113.226101 Prokop Hapala, Georgy Kichin, Christian Wagner, F. Stefan Tautz, Ruslan Temirov, Pavel Jelínek. Mechanism of high-resolution STM/AFM imaging with functionalized tips. Physical Review B, 2014; 90 (8) DOI: 10.1103/PhysRevB.90.085421

Single-atom gold catalysts may offer path to low-cost production of fuel and chemicals

 

November 27, 2014 Tufts University New catalysts designed and investigated by engineering researchers have potential to greatly reduce processing costs in future fuels like hydrogen. The catalysts are composed of a unique structure of single gold atoms bound by oxygen to sodium or potassium atoms, supported on non-reactive silica materials. They demonstrate comparable activity and stability with catalysts comprising precious metal nanoparticles on rare earth and other reducible oxide supports when used in producing highly purified hydrogen. New catalysts designed and investigated by Tufts University School of Engineering researchers and collaborators from other university and national laboratories have the potential to greatly reduce processing costs in future fuels, such as hydrogen. The catalysts are composed of a unique structure of single gold atoms bound by oxygen to several sodium or potassium atoms and supported on non-reactive silica materials. They demonstrate comparable activity and stability with catalysts comprising precious metal nanoparticles on rare- earth and other reducible oxide supports when used in producing highly purified hydrogen. The work, which appears in the November 27, 2014, edition of Science Express, points to new avenues for producing single-site supported gold catalysts that could produce high-grade hydrogen for cleaner energy use in fuel-cell powered devices, including vehicles. "In the face of precious metals scarcity and exorbitant fuel-processing costs, these systems are promising in the search for sustainable global energy solutions," says senior author Maria Flytzani-Stephanopoulos, the Robert and Marcy Haber Endowed Professor in Energy Sustainability and professor in the Department of Chemical and Biological Engineering at Tufts. Flytzani-Stephanopoulos's research group has been active in designing catalysts requiring a lower amount of precious metals to generate high-grade hydrogen for use in fuel cells. The water-gas shift reaction, in which carbon monoxide is removed from the fuel gas stream by reacting with water to produce carbon dioxide and hydrogen, is a key step in the process. Catalysts, such as metal oxide supported precious metals like platinum and gold, are used to lower the reaction temperature and increase the production of hydrogen. The Tufts group was the first to demonstrate that atomically dispersed gold or platinum on supports, such as cerium oxide, are the active sites for the water-gas shift reaction. Metal nanoparticles are "spectator species" for this reaction. Flytzani-Stephanopoulos says the new research suggests single precious metal atoms stabilized with alkali ions may be the only important catalyst sites for other catalytic reactions. "If the other particles are truly 'spectator species', they are therefore unnecessary. Future catalyst production should then focus on avoiding particle formation altogether and instead be prepared solely with atomic dispersion on various supports," says Flytzani-Stephanopoulos. The just published research describes how single gold atoms dispersed on non-reactive supports based on silica materials can be stabilized with alkali ions. As long as the gold atoms, or cations, are stabilized in a single-site form configuration, irrespective of the type of support, the precious metal will be stable and operate for many hours at a range of practical temperatures. "This novel atomic-scale catalyst configuration achieves the maximum efficiency and utilization of the gold," says Flytzani-Stephanopoulos, who directs the Tufts Nano Catalysis and Energy Laboratory. "Our work showed that these single-site gold cations were active for the low-temperature water-gas shift reaction and stable in operation at temperatures as high as 200°C." "Armed with this new understanding, practitioners will be able to design catalysts using just the necessary amount of the precious metals like gold and platinum, dramatically cutting down the catalyst cost in fuels and chemicals production processes," she adds. Story Source: The above story is based on materials provided by Tufts University. Note: Materials may be edited for content and length. Journal References: Ming Yang, Sha Li, Yuan Wang, Jeffrey A. Herron, Ye Xu, Lawrence F. Allard, Sungsik Lee, Jun Huang, Manos Mavrikakis, and Maria Flytzani-Stephanopoulos. Catalytically active Au-O(OH)x- species stabilized by alkali ions on zeolites and mesoporous oxides. Science, 27 November 2014 DOI: 10.1126/science.1260526 Y. Zhai, D. Pierre, R. Si, W. Deng, P. Ferrin, A. U. Nilekar, G. Peng, J. A. Herron, D. C. Bell, H. Saltsburg, M. Mavrikakis, M. Flytzani-Stephanopoulos. Alkali-Stabilized Pt-OHx Species Catalyze Low-Temperature Water-Gas Shift Reactions. Science, 2010; 329 (5999): 1633 DOI: 10.1126/science.1192449

Long-term complication rate low in nose job using patient's own rib cartilage

 

Using a patient's own rib cartilage (autologous) for rhinoplasty appears to be associated with low rates of overall long-term complications and problems at the rib site where the cartilage is removed, according to a report published online by JAMA Facial Plastic Surgery. Autologous rib cartilage is the preferred source of graft material for rhinoplasty because of its strength and ample volume. However, using rib cartilage for dorsal augmentation to build up the bridge of the nose has been criticized for its tendency to warp and issues at the cartilage donor site, such as pneumothorax (a collapsed lung) and postoperative scarring. Jee Hye Wee, M.D., of the National Medical Center, Seoul, South Korea, and co-authors reviewed the available medical literature to evaluate complications associated with autologous rib cartilage and rhinoplasty. Authors identified 10 studies involving 491 patients with an average follow-up across all studies of 33.3 moths. Results indicate that combined complication rates from the studies were 3.08 percent for warping, 0.22 percent for resorption, 0.56 percent for infection, 0.39 percent for displacement, 5.45 percent for hypertrophic chest scarring (keloids), 0 percent for pneumothorax and 14.07 percent for revision surgery. "The overall long-term complications associated with autologous rib cartilage use in rhinoplasty were low. Because warping and hypertrophic chest scarring had relatively high rates, surgeons should pay more attention to reduce these complications. ... Future analysis should include studies with larger pools of patients, clearer definitions of complications and longer-term follow-up to obtain more reliable results," the study concludes. Story Source: The above story is based on materials provided by The JAMA Network Journals. Note: Materials may be edited for content and length. Journal Reference: Jee Hye Wee, Min-Hyun Park, Sohee Oh, Hong-Ryul Jin. Complications Associated With Autologous Rib Cartilage Use in Rhinoplasty. JAMA Facial Plastic Surgery, 2014; DOI: 10.1001/jamafacial.2014.914

Transmission mechanism using magnetic levitating gear

 

Researchers from Universidad Carlos III de Madrid (UC3M) are developing a new transmission mechanism with no touching parts, based on magnetic forces which prevent friction and wear and make lubrication unnecessary. It can be applied in space travel and exploration but has also been adapted for use in other areas, such as the railroad and aircraft industries. This research is being carried out under the auspices of MAGDRIVE, a European research project coordinated by Professor José Luis Pérez Díaz, from the UC3M Instituto Pedro San Juan de Lastanosa, in which seven European entities participate. It consists of the development of a magnetic gear reducer, that is, a mechanism that transforms speed from an input axle to another in an output axle (as in a bicycle chain mechanism or the gearbox of an automobile). But in this case, unlike a conventional gear reducer, this transmission is produced without contact between the pieces thanks to the magnetism. One of its chief advantages is the absence of wear among the pieces, which makes lubrication unnecessary. As such, "the operating life of these devices can be much longer than the life of a conventional gear reducer with teeth, and can even work in cryogenic temperatures," notes one of the researchers, Efrén Díez Jiménez, from the UC3M Department of Mechanical Engineering. It can even continue to function after an event of overload. If the axle is blocked, "the parts simply slide amongst themselves, but nothing breaks." In addition, less noise is produced, vibration is reduced, and it is capable of through-wall transmission. A Gearbox that Levitates In addition to the contactless transmission, the axles are likewise contactless. "It is the first time in history that the input axle as well as the output axle of a gear reducer are floating without any kind of contact, and it can keep a mechanism which contains nothing else spinning at 3,000 revolutions per minute at cryogenic temperatures" says the main researcher on the project, José Luis Pérez Díaz. Although the main goal of the MAGDRIVE project is to build a prototype that can be used in extreme conditions in outer space, another one that can be used at room temperature has also been developed. For outer space, the cryogenic prototype has been developed. This type keeps the axles floating and it can work at a temperature of -210°C and in a vacuum. The mechanism integrates levitating superconductor bearings that generate stable forces of repulsion into its structure. This allows it to turn and, moreover, it stabilizes it against oscillating motion or possible imbalances. It is the first mechanism in history that does not have this type of friction. It has several applications in outer space, "from robot arms or antenna positioners, where high-precision movements are needed or when contamination from lubricants is undesired, to vehicles that, because of temperature or extreme conditions of absence of pressure, shorten the life of conventional mechanisms, as happens with the wheels of a Rover that has to go on Mars." The second prototype that has been developed can be used at room temperature. The magnetic reducer "substitutes the gear teeth with permanent magnets that repel and attract each other" so that "the transmission of couples and forces between the moving parts with contact is achieved," explains Efrén Díez Jiménez. Its applications can be transferred to any field where conventional mechanical reducers are used, such as self-propulsion, the railroad sector, the oil industry, or in mechanics and manufacturing in general, cite the researchers. Thanks to the absence of lubrication and oils, it can also be applied in the pharmaceutical, biomedical and food industries, where cleanliness requirements of are very strict. Although the cryogenic prototype was the global objective of the project because it solved the problem posed by the European Space Agency (ESA),"no doubt the room temperature prototype is the one that can have the biggest impact and industrial application," they conclude. The final results of the MAGDRIVE project have been presented at different conferences, congresses and meetings organized by ESA, NASA and ASME, generating a great deal of interest among participants. The researchers have published some of the results in the Journal of Engineering Tribology, among others. At present they are analyzing implementation of these types of systems in different industrial areas. And, the latest news: their research has been accepted for upcoming publication in the review Aerospace Science and Technology. Story Source: The above story is based on materials provided by Universidad Carlos III de Madrid - Oficina de Información Científica. Note: Materials may be edited for content and length.

Ancient dental plaque: A 'whey' into our milk drinking past?

 

Human skull (stock image). We drink milk because it is good for us, but we rarely stop to think "Why?" Archaeologists and geneticists have been puzzling this question since it was revealed that the mutations which enable adults to drink milk are under the strongest selection of any in the human genome. These mutations cause the intestinal enzyme lactase -- which digests lactose milk sugar during infancy -- to continue to be produced long after weaning. This lactase persistence is prevalent only in some populations around the world such as in Northern Europe. In most other people of the world, the lactose cannot be properly digested and can cause diarrhea, or other symptoms of lactose intolerance resulting from the gases produced by fermentation by the gut bacteria. Some dairy products such as yoghurt and cheese have had their lactose content reduced or removed through processing. In the case of cheese, the lactose ends up in the whey, where it is often fed to pigs and other animals. If it is so easy to remove milk sugars, and the mutation is only required for drinking raw milk or whey -- why is it under such strong selection? An international team of researchers involving the Universities of York, Oklahoma and Copenhagen, and University College London (UCL) has shed new light on this puzzling question through an unusual source -- investigations of calcified dental plaque on ancient human teeth. To understand how, where and when humans consumed milk products, it is necessary to link evidence of consumption directly to individuals and their livestock. Previous research by archaeologists has used indirect lines of evidence, such a high frequency of adult females in animal herds or milk lipids present on pots, to identify evidence of dairying. Now a breakthrough by the international team, reported in the journal Scientific Reports, provides the first direct evidence of milk drinking from an increasingly important archaeological reservoir -- human dental calculus, a mineralized form of dental plaque. Using the latest mass spectrometry-based techniques for ancient protein sequencing, the team detected a milk protein, beta-lactoglobulin (which they had previously reported from a modern dental plaque sample) in ancient remains. Lead author Jessica Hendy, from the University of York's BioArCh research facility, said: "It seemed too good to be true; beta-lactoglobulin is the dominant whey protein -- the one used by bodybuilders to build muscle mass -- and therefore the ideal marker for milk consumption. We kept finding sequences of beta-lactoglobulin and at first we thought it could be modern contamination. But we repeated the analysis several times, at three different laboratories in three different countries, each time finding the same results." Lead author Dr Christina Warinner, from the Department of Anthropology, University of Oklahoma, said: "The study has far-reaching implications for understanding the relationship between human diet and evolution. Dairy products are a very recent, post-Neolithic dietary innovation, and most of the world's population is unable to digest lactose, often developing the symptoms of lactose intolerance." Professor Dallas Swallow, from the Research Department of Genetics, Evolution and Environment at UCL, added: "It is only within the last several thousand years that genetic mutations arose in Europe, East Africa, and the Arabian Peninsula that allowed lactase to persist into adulthood, a genetic trait that enables lifelong milk consumption." The new research provides direct protein evidence that cattle, sheep, and goat whey has been consumed by human populations for at least 5,000 years. This corroborates previous isotopic evidence for milk fats identified on pottery and cooking utensils in early farming communities. Until now it has been difficult to investigate both human genetic milk adaptations and direct evidence of milk consumption at the same time, in part because milk preserves so poorly in the archaeological record. "The discovery of milk proteins in human dental calculus will allow scientists to unite these lines of evidence and compare the genetic traits and cultural behaviors of specific individuals who lived thousands of years ago," says Dr Warinner.The team found direct evidence of milk consumption preserved in human dental plaque from the Bronze Age to the present day. Professor Matthew Collins, of BioArCh in York's Department of Archaeology, said: "Some of the findings were as we expected. For example, we did not find any evidence of milk protein in 19th century West African individuals from regions where dairying was uncommon. But we found widespread evidence for milk consumption at European sites spanning a period of 5,000 years." Dr Camilla Speller, from York's BioArCh research facility, said: "Most of the molecular evidence for milk consumption has previously come from residues on ceramics. While pot residues can tell you that people are using dairy products, it can't tell you which individuals in the group are actually consuming the milk. This study is very exciting, because for the first time, we can link milk consumption to specific skeletons, and figure out who has access to this important nutritional resource." Dr Enrico Cappellini, from the Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, says the milk protein beta-lactoglobulin is also an important find because it contains sequence variants that allow different milk-producing livestock to be distinguished. "We found widespread evidence of cows' and sheep milk consumption as early as the Bronze Age, whereas evidence for goat milk consumption was limited to Bronze Age northern Italy," he said.