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.

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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.

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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.

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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. 

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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.

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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.

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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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