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Friday, 30 January 2015

‘Nanowire’ crystals with superconducting properties developed

‘Nanowire’ crystals with superconducting properties developed




A new type of ‘nanowire’ crystals that fuses semiconducting and metallic materials on the atomic scale could lay the foundation for future semiconducting electronics. Researchers at the University of Copenhagen are behind the breakthrough, published inNature Materials, which has great potential.
The development and quality of extremely small electronic circuits are critical to how and how well future computers and other electronic devices will function. The new material, comprised of both a semiconductor and metal, has a special superconducting property at very low temperatures and could play a central role in the development of future electronics.
“Our new material was born as a hybrid between a semiconducting nanowire and its electronic contact. Thus we have invented a way to make a perfect transition between the nanowire and a superconductor. The superconductor in this case is aluminium. There is great potential in this,” said Thomas Sand Jespersen, Associate Professor who has worked in the field for more than 10 years, ever since research into nanowire crystals has existed at the Nano-Science Center at the Niels Bohr Institute.
Nanowires are extremely thin nanocrystal threads used in the development of new electronic components, like transistors and solar cells. Part of the challenge of working with nanowires is creating a good transition between these nanowires and an electrical contact to the outside world. Up until now, researchers, not just at the Niels Bohr Institute, but from all over the world, have cultured nanowires and the contact separately. However, with the new approach, both the quality and the reproducibility of the contact have improved considerably.
“The atoms sit in a perfectly ordered lattice in the nanowire crystal, not only in the semiconductor and the metal, but also in the transition between the two very different components, which is significant in itself. You could say that it is the ultimate limit to how perfect a transition one could imagine between a nanowire crystal and a contact. Of course this opens many opportunities to make new types of electronic components on the nanoscale and in particular, this means that we can study the electrical properties with much greater precision than before,” explained Peter Krogstrup, Assistant Professor, University of Copenhagen.
In their publication in Nature Materials, the research group has demonstrated this perfect contact and its properties and has also shown that they can make a chip with billions of identical semiconductor-metal nanowire hybrids.
“We think that this new approach could ultimately form the basis for future superconducting electronics, and that is why the research into nanowires is interesting for the largest electronics companies,” said Thomas Sand Jespersen.

New catalyst process for rapid polymerization uses light, not metal


University of California Santa Barbara researchers develop a metal-free atom transfer radical polymerization (ATRP) process that uses an organic-based photocatalyst. A team of chemistry and materials science experts from University of California, Santa Barbara and The Dow Chemical Company has created a novel way to overcome one of the major hurdles preventing the widespread use of controlled radical polymerization.
In a global polymer industry valued in the hundreds of billions of dollars, a technique called Atom Transfer Radical Polymerization is emerging as a key process for creating well-defined polymers for a vast range of materials, from adhesives to electronics. However, current ATRP methods by design use metal catalysts, a major roadblock to applications for which metal contamination is an issue, such as materials used for biomedical purposes. This new method of radical polymerization doesn’t involve heavy metal catalysts like copper. Their innovative, metal-free ATRP process uses an organic-based photocatalyst - and light as the stimulus for the highly controlled chemical reaction.
“The grand challenge in ATRP has been: How can we do this without any metals? We looked toward developing an organic catalyst that is highly reducing in the excited state, and we found it in an easily prepared catalyst, phenothiazine,” said Craig Hawker, Director, Dow Materials Institute, UCSB.
“It’s ‘drop-in’ technology for industry. People are already used to the same starting materials for ATRP, but now we have the ability to do it without copper,” said Javier Read de Alaniz, principal investigator and professor of chemistry and biochemistry at UCSB.
Copper, even at trace levels, is a problem for microelectronics because it acts as a conductor, and for biological applications because of its toxicity to organisms and cells.
Read de Alaniz, Hawker, and postdoctoral researcher Brett Fors, now with Cornell University, led the study that was initially inspired by a photoreactive Iridium catalyst. Their study was recently detailed in a paper titled “Metal-Free Atom Transfer Radical Polymerization,” published in the Journal of the American Chemical Society. The research was made possible by support from Dow, a research partner of the UCSB College of Engineering.
ATRP is already used widely across dozens of major industries, but the new metal-free rapid polymerization process “pushes controlled radical polymerization into new areas and new applications,” according to Hawker. “Many processes in use today all start with ATRP. Now this method opens doors for a new class of organic-based photoredox catalysts,” said Hawker.
Controlling radical polymerization processes is critical for the synthesis of functional block polymers. As a catalyst, phenothiazine builds block copolymers in a sequential manner, achieving high chain-end fidelity. This translates into a high degree of versatility in polymer structure, as well as an efficient process.
“Our process doesn’t need heat. You can do this at room temperature with simple LED lights. We’ve had success with a range of vinyl monomers, so this polymerization strategy is useful on many levels,” said Hawker.
“The development of living radical processes, such as ATRP, is arguably one of the biggest things to happen in polymer chemistry in the past few decades. This new discovery will significantly further the whole field,” added Hawker.

Friday, 16 January 2015

Nasal spray may treat Alzheimer’s, say scientists



A nasal spray that contains a man-made form of insulin may improve working memory and other mental capabilities in adults with mild cognitive impairment and Alzheimer’s, scientists have found. The study led by researchers at Wake Forest Baptist Medical Center studied 60 adults diagnosed with amnesic mild cognitive impairment (MCI) or mild to moderate Alzheimer’s dementia (AD).
Researchers found that those who received nasally administered 40 international unit (IU) doses of insulin detemir, a manufactured form of the hormone, for 21 days showed significant improvement in their short-term ability to retain and process verbal and visual information compared with those who received 20 IU doses or a placebo.
Recipients of 40 IU doses carrying the APOE-e4 gene - known to increase the risk for Alzheimer’s - recorded significantly higher scores than those who received the lower dosage, while non-carriers across all three groups posted significantly lower scores. Previous trials had shown promising effects of nasally administered insulin for adults with AD and MCI, but this study was the first to use insulin detemir.

Beer digesting bacteria may fight against diseases, finds new study


A recent study led by Harry Gilbert, professor of biochemistry at Newcastle University, Eric Martens of the University of Michigan’s Department of Microbiology and Immunology, and Wade Abbott, research scientist at Agriculture and Agri-Food Canada, has identified the complex machinery that targets yeast carbohydrates.
The study was published in the journal Nature and explained how our stomach has a certain bacteria that help us digest yeast and other complex carbohydrates. The bacteria is also found in beer and breads and is responsible for the bubbles in beer. This study shows that certain microbes in our digestive tract have evolved over the years to become capable of breaking down complex carbohydrates. It is these complex carbs that make up the yeast cell wall.
The research has unraveled the mechanism by which B thetaiotaomicron has learned to feast upon difficult to break down complex carbohydrates called yeast mannans. Mannans, derived from the yeast cell wall, are a component in our diet from fermented foods including bread, beer, wine and soy sauce.
“One of the big surprises in this study was that B thetaiotaomicron is so specifically tuned to recognise the complex carbohydrates present in yeasts, such as those present in beer, wine and bread,” said Martens.
“However, these bacteria turned out to be smarter than we thought: they recognise and degrade both groups of carbohydrates, but have entirely separate strategies to do so despite the substantial chemical similarity between the host and yeast carbohydrates,” added Martens.
The new findings provide a better understanding of how our unique intestinal soup of bacteria - known as the microbiome - has the capacity to obtain nutrients from our highly varied diet. The results suggest that yeast has health benefits possibly by increasing the Bacteroides growth in the microbiome.
Experts believe that the discovery of this process could accelerate the development of prebiotic medicines to help people suffering from bowel problems and autoimmune diseases.

Developing light-activated nanocarrier to transport proteins into cells


University of California, Santa Barbara’s (UCSB) Reich Group uses lasers to spatially and temporally control the release of a tagged protein inside a cell. Optogenetics, which uses light to control cellular events, is poised to become an important technology in molecular biology and beyond. The Reich Group in UC Santa Barbara’s Department of Chemistry and Biochemistry has made a major contribution to this emergent field by developing a light-activated nanocarrier that transports proteins into cells and releases them on command. The findings appear in the journal Molecular Pharmaceutics.
Using inorganic gold nanoshells and a near-infrared laser, UCSB biochemistry professor Norbert Reich and graduate student Demosthenes Morales demonstrate for the first time a method that affords both spatial and temporal control over protein delivery in cells.
“You can point the laser at cells where and when you want a particular protein to be turned on. And that means you can ask biological questions that you could never ask before because you’re able to say I want this one cell to do this,” said Reich.
The researchers exploited the receptors on prostate cancer cells, which rely on the recognition of a C-end rule internalizing peptide that has been fused to the end of a green fluorescent protein. This peptide is very specific for the receptor and once the two meet, it actually takes in the protein-loaded nanoparticles and shepherds them into the cell via endocytosis, a process that brings large molecules into cells.
The team used a modular nickel linking layer on the surface of the nanoparticles that is able to support different kinds of proteins fused with a polyhistidine tag commonly found on proteins expressed in labs. “We want this to be applicable to any type of protein that has a polyhistidine tail, so if you synthesize or grow proteins in a lab, you can easily load the protein onto our nanoparticles,” said Morales.
While the Reich Group’s hollow gold nanoshells are effective carriers, transporting large biomolecules such as proteins into cells is only half the battle. In order for the protein to be effective once inside the cell, it must be released from the vesicle (endosome) holding it. The UCSB design enables that to happen.
“When we excite these hollow gold nanoshells with light, the surface of the nanoparticle becomes somewhat hot. The light not only releases the cargo that’s on the surface but also causes the formation of vapor bubbles, which expand and eventually pop the vesicle, allowing for endosome escape,” said Morales.
The Reich Group’s construct is designed around the advantage of protein delivery’s specificity. “The best thing about our platform is that it has a wide range of applicability. Not only do we have the ability to target with a laser where and when we want to release our therapeutic, but we also leverage the fact that the protein itself is very specific. We have specificity in terms of time and we have specificity toward the target. This is why proteins are very fascinating as a potent therapeutic,” said Morales.
According to Reich, this technology has important implications for basic research. “Biologists are going to make use of this kind of technology but they aren’t going to develop it. There are a few people on campus who could use this technology so we have a unique opportunity at UCSB to be the lead in interfacing between the developers and the users,” said Reich.

Scientists create first new antibiotic in nearly three decades


In a massive breakthrough, scientists have created the first new antibiotic in more than three decades, Teixobactin, that can treat many common bacterial infections such as tuberculosis, septicemia and C Diff or clostridium difficile colitis.
The discovery comes at a time when World Health Organization has sent out warnings that humanity is staring at a post-antibiotic era when common infections will no longer have a cure. The first antibiotic, Penicillin, was discovered by Alexander Fleming in 1928, and more than 100 compounds have been found since then, but no new class has been found since 1987.
Antibiotics have been magic bullets for human health for decades but irrational use has made most bugs resistant to these. Kim Lewis, Professor, Northeastern University announced the discovery of the antibiotic that eliminates pathogens without encountering any detectable resistance. Lewis and Northeastern biology professor Slava Epstein co?authored the finding with colleagues from the University of Bonn in Germany, Novo Biotic Pharmaceuticals in Cambridge, Massachusetts, and Selcia Ltd in the United Kingdom.
Most antibiotics target bacterial proteins, but bugs can become resistant by evolving new kinds of proteins. What’s unique about Teixobactin is that it launches a double attack on the building blocks of bacterial cell walls. Experts say this will pave the way for a new generation of antibiotics because of the way it was discovered.
Teixobactin could be available in the next five years. Its testing on mice has shown it clears infections without side-effects. The NU team led by Prof Lewis is now concentrating on upscaling production of Teixobactin to test it on humans.
Northeastern researchers’ pioneering work to develop a novel method for growing uncultured bacteria led to the discovery of the antibiotic, and Lewis’s lab played a key role in analyzing and testing the compound for resistance from pathogens. Lewis said this marks the first discovery of an antibiotic to which resistance by mutations of pathogens have not been identified.
“So far, the strategy has been based on developing new antibiotics faster than the pathogens acquire resistance. Teixobactin presents a new opportunity to develop compounds that are essentially free of resistance,” said Lewis.
The screening of soil micro-organisms has produced most antibiotics, but only one per cent of these will grow in the lab, explained Lewis. He and Epstein spent years seeking to address this problem by tapping into a new source of antibiotics beyond those created by synthetic means: uncultured bacteria, which make up 99 per cent of all species in external environments.
They developed a novel method for growing uncultured bacteria in their natural environment. Their approach involves the iChip, a miniature device Epstein’s team created that can isolate and help grow single cells in their natural environment and provide researchers with much improved access to uncultured bacteria.
“Novo Biotic has assembled about 50,000 strains of uncultured bacteria and discovered 25 new antibiotics, of which Teixobactin is the latest and most interesting. Our impression is that nature produced a compound that evolved to be free of resistance. This challenges the dogma that we’ve operated under that bacteria will always develop resistance. Well, maybe not in this case,” said Lewis.

Novel nanowire clothing could keep people warm


To stay warm when temperatures drop outside, we heat our indoor spaces - even when no one is in them. But scientists have now developed a novel nanowire coating for clothes that can both generate heat and trap the heat from our bodies better than regular clothes. They report on their technology, which could help us reduce our reliance on conventional energy sources, in the ACS journal Nano Letters.
Researcher Yi Cui and colleagues noted that nearly half of global energy consumption goes toward heating buildings and homes. But this comfort comes with a considerable environmental cost – it’s responsible for up to a third of the world’s total greenhouse gas emissions. Scientists and policymakers have tried to reduce the impact of indoor heating by improving insulation and construction materials to keep fuel-generated warmth inside. Cui’s team wanted to take a different approach and focus on people rather than spaces.
The researchers developed lightweight, breathable mesh materials that are flexible enough to coat normal clothes. When compared to regular clothing material, the special nanowire cloth trapped body heat far more effectively. Because the coatings are made out of conductive materials, they can also be actively warmed with an electricity source to further crank up the heat. The researchers calculated that their thermal textiles could save about 1,000 kilowatt hours per person every year — that’s about how much electricity an average U.S. home consumes in one month.

New method to detect estrogen, could improve cancer research


Scientists at the Shimadzu Institute for Research Technologies and the Department of Chemistry and Biochemistry at The University of Texas at Arlington have collaborated to develop a new method for detecting trace amounts of estrogen in small samples that holds the potential to improve research into cancer and other diseases.
The hormone estrogen plays an important role in the human body and has been linked to everything from tumor growth to neuron loss during Alzheimer’s disease. But detecting very small amounts of it in blood and other biological fluids can be difficult for health researchers, especially in the limited amounts available in laboratory experiments. In response, a UT Arlington research team applied advanced mass spectrometry and chromatography instrumentation available at the Shimadzu Institute to develop a sensitive and efficient method for detecting trace amounts at less than 10 parts per trillion in a 100 microliter sample, said Kevin Schug, Shimadzu Distinguished Professor of Analytical Chemistry, UT Arlington. One part per trillion is the equivalent of a drop of water in 20 Olympic-size swimming pools.
“This new method pushes the detection limit for estrogens to a level that is applicable to research, human health, medicine, and environmental analysis. It is being instituted as a routine service for research means that all researchers now have the capability to more closely relate research model findings to human health and physiology. This project represents the collaborative capability that the Shimadzu Institute possesses in helping augment groundbreaking research here at UT Arlington,” said Jose Barrera, Director, Shimadzu Institute and a co-author on the new paper published by the journal Analytica Chimica Acta.
Jana Beinhauer, a visiting scientist from Palacky University in the Czech Republic who spent nine months working at UT Arlington, and Liangqiao Bian, of the Shimadzu Center for Advanced Analytical Chemistry, are lead authors on the new paper. In addition to Barrera and Schug, other co-authors are: Hui Fan, a recent Ph.D. graduate from the UT Arlington Department of Chemistry and Biochemistry; Marek Sebela, of Palacky University; and Maciej Kukula, of the Shimadzu Center for Advanced Analytical Chemistry. Mass spectrometry and chromatography are ways to separate, identify, and quantify molecules in a complex mixture. The process involving liquid chromatography-electrospray ionization-tandem mass spectrometry relies on a vital step called “charge derivatization” or using a permanently charged reagent to selectively trap the estrogens and isolate them from the lipids and proteins that could interfere with estrogen detection, said Schug.
“We are dealing with extremely small quantities and there are a lot of things out there that look like estrogen. You have to have this ability to separate out these individual components and detect them accurately,” said Schug.
Many current estrogen detection methods rely on the use of an antibody, a type of protein detection system. Those processes and others now being used by researchers are more time consuming, less reliable and require a larger sample than the 100 microliters used in the UT Arlington experiments, said Schug. The new UT Arlington method can be accomplished in less than 25 minutes, including sample preparation, he said.
“Estrogens perform important biological functions not only in sexual development and reproduction, but also in modulating many other processes impacting health and diseases in human and animals. The metabolically active estrogens exert strong biological activities at very low circulating concentrations. Therefore this research is very important for finding sensitive, efficient, fast, automated and simple method how to determine the trace estrogens in serum,” said Beinhauer.

Encapsulating nitric oxide within metal-organic frameworks


A group of scientists led by researchers at the Universite de Versailles’ Institut Lavoisier in France has worked out how to stably gift-wrap a chemical gas known as nitric oxide within metal-organic frameworks. Such an encapsulated chemical may allow doctors to administer nitric oxide in a more highly controlled way to patients, suggesting new approaches for treating dangerous infections and heart conditions with the biologically-active substance.
Not to be confused with the chemically-distinct anesthetic dentists use -nitrous oxide (NO2), also known as laughing gas - nitric oxide (NO) is one of very few gas molecules known to be involved in biological signaling pathways, the physiological gears that make the body tick at the microscopic level. It is very active biologically and can be found in bacteria, plant, animal and fungi cells.
In humans, NO is a powerful vasodilator, increasing blood flow and lowering vascular pressure. For this reason, gaseous NO is sometimes used to treat respiratory failure in premature infants. It also has strong antibacterial potency, owing to its molecular action as a biologically disruptive free radical, and cells in the human immune system naturally produce NO as a way of killing pathogenic invaders. Additionally, nitric oxide is believed to be the main vasoactive neurotransmitter regulating male erection, as aging nerves with reduced stimulation can inhibit the release of the molecule, thus causing erectile dysfunction. This, of course, can be mediated by taking nitric oxide supplements to achieve an erection.
While such activity would seem to make NO a prime candidate for drug design, the problem is delivery -- because it is a gas. In recent years, the gas storage capacity and biocompatibility of metal-organic-frameworks -- dissolvable compounds consisting of metal ions and rigid organic chemicals that can stably trap gas molecules -- have gained significant attention as candidates for delivering gas-based drugs. The new work extends this further than ever before, showing that these metal-organic frameworks can store and slowly deliver NO over an unprecedented amount of time, which is key for the drug’s anti-thrombogenic action.
“This is an elegant and efficient method to store and deliver large amounts of NO for antibacterial purposes. Or it can release controlled amounts of nitric oxide at the very low biological level for a prolonged period of time, in order to use it as a way to inhibit platelet aggregation,” said Christian Serre, CNRS research director, Institut Lavoisier de Versailles.
Serre’s consortium has previously reported the use of porous hybrid solids, such as metal-organic-frameworks, for the controlled delivery of nitric oxide gas. Their current paper on derivatives of iron polycarboxylates as framework candidate appears in the journal APL Materials, from AIP Publishing.
Serre and his group worked in collaboration with Russell Morris’s team at the University of St Andrews in Scotland and researchers from Universite de Basse-Normandie in France. The groups analyzed the NO adsorption and release properties of several porous biodegradable and biocompatible iron carboxylate metal-organic frameworks by use of infrared spectroscopy analysis, adsorption & desorption isotherms and water-triggered release tests.
In doing so, they confirmed the large nitric oxide absorption capacity of the iron frameworks, and that the NO was strongly bonding to the acidic metal sites on the molecules. Serre’s group and coauthors also found that partially reducing the iron (III) into iron (II) enhances the affinity of the NO molecules for the framework. This strong interaction allows for a controlled release for a prolonged state of time - days, at the biological level. This time scale depends on both the metal-organic framework structure and the oxidation state of iron, which can be carefully calibrated as needed for drug treatment.
These performances, associated with the biodegradable and low toxicity character of these metal-organic frameworks, might pave the way for their use in medical therapies or cosmetics formulation, which is one of the objectives of Serre’s consortium in the near future. Current and forthcoming work includes using further spectroscopic experiments to understand the complex behavior of the iron frameworks once loaded with nitric oxide.

Hydrogen-rich compounds are better superconductors under extreme pressure


Hydrogen-rich compounds under extreme pressure may be better superconductors than the best conventional ones around, according to scientists in Germany. The results suggest metallic hydrogen-based compounds may offer up to 50 times less electrical resistivity than copper and conduct at -83°C, the highest recorded temperature for a hydrogen-rich superconductor. The best superconductors in existence today stop working at -109°C.
The work conducted by Mikhail Eremets and his colleagues at the Max Planck Institute for Chemistry, Germany, is rooted in a theory proposed by Eugene Wigner and Hillard Bell Huntington back in 1935. The physicists predicted pure hydrogen becomes metallic at very high pressures – approximately 25GPa.
Theory predicts such a phase would conduct at ‘room temperature or even higher,’ according to Isaac Silvera, from the University of Harvard, US, who was not involved in the work. One of the reasons for this is the hydrogen lattices’ ability to vibrate and force electrons into pairs. These Cooper pairs flow freely through the metallic hydrogen without any resistance.
But obtaining the sought-after metal has proven ‘very difficult’ in the past few decades, Silvera goes on to explain. To be any use for real world applications the metallic hydrogen needs to be metastable and remain in this metallic state at everyday pressure, something which has never been achieved.
“If we can’t get pure metallic hydrogen or if that’s more challenging, what about looking at [hydrogen-rich] compounds,” said Silvera. That is exactly what Eremets and his colleagues set out to do.
The team in Germany placed hydrogen sulfide (H2S), a toxic gas that smells like rotten eggs, into a diamond anvil cell (DAC). Placed between the flattened tips of two diamonds in a metal tube, the gas is condensed under low temperatures to produce liquid H2S. When the H2S is subjected to tremendous pressures in the DAC it develops a metallic character. Using this DAC the team were able to produce pressures comparable to those at the centre of planets – up to 150GPa.
Eremets and his colleagues found that the resulting metallic compound superconducted at 190K (-83°C) at pressures of 150GPa. Although the team know H2S superconducts, it still remains unclear why. The team said, H2S may dissociate and form a hydride, which may be a likely cause of the high superconductivity.
Silvera welcomed the work from the Max Planck Institute but added that more will have to be done to understand the nature of this superconductor. 

Improving rare-earth separation process


Department of Energy’s Ames Laboratory and Critical Materials Institute materials chemist Anja Mudring is harnessing the promising qualities of ionic liquids, salts in a liquid state, to optimize processes for critical materials.
“Ionic liquids have a lot of useful qualities, but most useful for materials processing is that ionic liquids are made up of two parts: the cation and the anion. We can play around with the chemical identities of each of those components and that opens the doors to huge amount of options. That means we can really engineer ionic liquids with specific functions in mind,” said Mudring.
One such function is improving the rare-earth separation process, either for extracting rare earths from ore or recycling rare earths from discarded magnets.
“We are tuning the ionic liquids in such a way that they dissolve rare-earth oxides and then we’re using electrodeposition, where electricity is run through a liquid to create a chemical change to get the rare earth in metal form,” said Mudring, who is also a professor of materials science and engineering at Iowa State University.
Traditionally, electrodeposition processes are extremely high temperature and often require corrosive chemicals. But Mudring’s process requires much lower temperatures and ionic liquids are less hazardous, so less energy is needed and the process is safer and greener. Mudring’s group is also using ionic liquids to create phosphors for compact fluorescent light bulbs.
“We’re using ionic liquids, putting them in a microwave, energizing them, and creating a phosphors material. The phosphors particles are less than 10 nanometers, which means they do not scatter light, key for optical applications like for compact fluorescent light bulbs,” said Mudring.
Better yet, Mudring’s process also reduces the amount of rare-earth materials required in the process, and may someday make it possible to replace mercury vapor with less-hazardous noble gases in Compact fluorescent lamp (CFLs). And looking farther down the road, the new phosphors could also be used in Light-emitting diode (LEDs) as they continue to replace CFLs.
“Ionic liquids are the key to the improvements in this material synthesis. They function as the solvent, a safer one than an alcohol or other combustible solvent. And they are also the reaction partner: Here, the ionic liquid is the fluoride source, so we can omit hazardous hydrofluoric acid from the process. Again, that makes the process safer and cleaner. And they even function to stabilize the nanoparticles created in the process, eliminating the need for an additional stabilizer. Three functions in one! Add to that how efficiently ionic liquids take up microwave energy and there’s just huge potential there for improving materials synthesis,” said Mudring.

Mistletoe may fight obesity-related liver disease


Mistletoe may have better effect on liver health. Researchers have found that a compound produced by a particular variety of the plant can help fight obesity-related liver disease in mice. Their study appears in ACS’ Journal of Agricultural and Food Chemistry.
Researcher Jungkee Kwon and colleagues noted that, according to recent research, Korean mistletoe produces a number of biologically active compounds. These include familiar ones such as steroids and flavonoids. Also, extracts from the plant have shown anti-obesity effects, but no one had confirmed which specific molecules were involved. Kwon’s team wanted to investigate the matter and see if the key ingredient could also help fight fatty liver disease, which is associated with obesity and can progress to liver failure in some cases.
The researchers identified viscothionin as the compound in Korean mistletoe that affects fat metabolism in the liver. When they treated obese mice with it, their body and liver weights dropped. The scientists concluded that viscothionin could be explored as a potential therapeutic agent for the treatment of nonalcoholic fatty liver disease.

Newly discovered cyclic copper complex converts carbon dioxide to oxalate



LSU researchers are contributing to ongoing work aimed at reducing the amount of carbon dioxide released in the environment. The research team, led by Andrew Maverick, Philip & Foymae West Distinguished Professor of Chemistry and acting associate dean in the LSU College of Science, has discovered a cyclic copper complex that converts carbon dioxide to oxalate, changing the environmental pollutant into a more useful organic compound.
Carbon dioxide is naturally present in the air as part of the normal circulation of carbon among the Earth’s atmosphere, ocean, and land surface; however, human activities are shifting the natural carbon cycle by adding more carbon dioxide and influencing nature’s ability to remove the greenhouse gas from the atmosphere.
“The particular chemistry we have discovered is more interesting than most of the things we have done, because everyone wants to solve this carbon dioxide problem. This is just one step to solving the puzzle,” said Maverick.
Maverick and his research team have developed a three-step reaction sequence in which a copper complex converts carbon dioxide to oxalate under mild conditions. The copper complex is first reduced by reaction with sodium ascorbate or vitamin C. The reduced complex selectively reacts with carbon dioxide from air and fixes it into oxalate, with the oxalate ion bridging between two copper atoms.
The team, which includes Maverick, LSU Research Associate Frank Fronczek and post-doctoral researcher Uttam Pokharel, have co-authored a paper about their discovery to be published in the December edition ofNature Communications.
A key component to this discovery was the development of a compound that would react with carbon dioxide. The research team created more than 50 different compounds before finding the one that would react with carbon dioxide.
“Carbon dioxide does not want to react with just any compound. Even highly energetic molecules often do not react with CO2. So, it is important to search for compounds like our copper complex, which will convert CO2 into something with a little more stored energy,” said Maverick.
LSU has applied for an international patent for the team’s work, but Maverick warns that that this discovery does not signal the end of the world’s climate change issues. “Our compound takes four to five days to react. This is much too slow for anything that is of practical use,” said Maverick.
Maverick and his colleagues are currently working on ways to speed up this process. Conversion of carbon dioxide to useful organic compounds will continue to be an active area of research given its connection to global climate change and the depletion of fossil fuels. They are also investigating whether other compounds besides vitamin C can be used to drive the conversion.

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