Tech

Scientists at the U.S. Department of Energy's Ames Laboratory and their partners from Clemson University have discovered a green, low-energy process to break down polystyrene, a type of plastic that is widely used in foam packaging materials, disposable food containers, cutlery, and many other applications.

Polystyrene is part of a much larger global plastic waste problem. Hundreds of millions metric tons of polymers are produced each year, a large majority of which is discarded after use. Due to the chemical stability and durability of industrial polymers, plastic waste does not easily degrade in landfills and is often burned, which produces carbon dioxide and other hazardous gases. In order to stop the growing flood of polymer waste and reduce carbon dioxide emissions, plastics have to be recycled or converted into new value-added products.

Currently, recycling of the vast majority of plastics is not economically feasible; their sorting and separation are time and labor intensive, while chemical processing and remanufacturing requires a significant energy input and toxic solvents. Re-processed polymers often show inferior performance to that of the freshly manufactured "made from scratch" materials.

A team of scientists at Ames Laboratory used processing by ball-milling to deconstruct commercial polystyrene in a single step, at room temperature, in ambient atmosphere in the absence of harmful solvents. Ball-milling is a technique that places materials in a milling vial with metal ball bearings which is then agitated until a desired chemical reaction occurs. Called mechanochemistry, this experimental approach has numerous applications in new materials synthesis, and attractive features where plastics recycling is concerned.

The deconstruction of polystyrene proceeds through a series of chemical events involving mechanical cutting apart of the macromolecules, which generates free radicals detectable in the milled material even after its prolonged exposure to air. The metal bearings used for milling and the ambient oxygen act as co-catalysts that enable extraction of the monomeric styrene from the oligomeric radical-bearing species formed. The experiments showed that the temperature rise in the material during milling is not responsible for the observed phenomenon since the temperature inside the milled powder does not exceed 50oC while the thermal decomposition of polystyrene in air starts at about 325oC. The Clemson's group confirmed the comprehensive deconstruction of the original polymer into smaller fragments, oligomeric materials, suitable for further processing into new value-added products.

"This method represents an important breakthrough that enables dismantling of a polymer simultaneously with its break-down under ambient conditions, that is, ~300oC below the thermal decomposition temperature of the pristine material" said Ames Laboratory Senior Scientist Viktor Balema. "We think this proof of concept is an exciting possibility for developing new recycling technologies for all kinds of plastics, and that will contribute to establishment of the circular economy."

His partner from Clemson University, Kentwool Distinguished Professor Igor Luzinov, further commented that "this discovery opens new avenues for low temperature recovery of monomers from multicomponent polymer based systems such as composites and laminates. Also, our technology will allow extracting the monomer from crosslinked materials containing styrene units in their structures."

Alfred P. Sloan Foundation Research Fellow, Professor Aaron Rossini of Iowa State University, further noted that "electron paramagnetic resonance spectroscopy shows large concentrations of free radical carbon-centered species in polystyrene that was milled in air. This is a startling result because free radicals are normally very reactive. Also, the presence of the radicals gives direct evidence that the milling directly causes scission of the polymer chains. We expect that the reactive sites associated with the free radicals can be used to functionalize the processed polymers to obtain new value-added products."

BIRMINGHAM, Ala. - The triggers and causes of a severe scarring disease of the lungs -- idiopathic pulmonary fibrosis, or IPF -- remain unclear.

Now research published in Science Translational Medicine shows how cadmium and carbon black can trigger lung macrophages to produce a modified protein, citrullinated vimentin, or cit vim, which leads to lung fibrosis. Researchers from the University of Alabama at Birmingham and three other American universities also describe a sequence of mechanistic steps in lung macrophages and lung fibroblasts that leads to the lung scarring.

One of the enzymes involved in these steps -- peptidylarginine deiminase 2, or PAD2 -- may be a promising target to attenuate cadmium/carbon black-induced fibrosis, they say. The researchers also report a potential disease model for lung fibrosis and IPF -- the use of cadmium chloride to induce interstitial fibrosis in mice.

The study, led by Veena Antony, M.D., included patients with IPF, tissue experiments and mouse models. Antony is the Endowed Professor of Environmental Medicine in the UAB Department of Medicine, and she directs the UAB Superfund Research Program.

"Altogether, these studies support a role for cit-vim as a damage-associated molecular pattern molecule, or DAMP, that is generated by lung macrophages in response to environmental cadmium/carbon black exposure," Antony said. Cadmium is a toxic heavy metal recognized as a cause of lung fibrosis. Cadmium can adsorb onto carbon black particles. In the lung, such particles are ingested by macrophages, the sentinel host defense cells of the mammalian lung. Up to two-thirds of IPF patients have a history of smoking, and cigarette smoke contains both cadmium and carbon black. Air pollution from biomass fuels and coal furnaces is also a source of the two pollutants.

Data from human subjects

The researchers evaluated cadmium and cit-vim accumulation in tissue, using lung biopsies
from 25 subjects with IPF -- eight never-smokers and 17 smokers -- and 14 controls -- eight never-smokers and six smokers.

Researchers found that both cadmium and carbon black were significantly accumulated in the lung tissue from IPF subjects. Furthermore, the cadmium concentrations in the IPF lung tissues directly correlated with cit-vim amounts, and the cit-vim amounts were higher in smoker IPF tissue compared to non-smoker IPF tissue. Also, subjects with IPF had higher levels of cit-vim in plasma, and those amounts inversely correlated with lung function. Lung macrophages from subjects with IPF had significantly increased vimentin and cit-vim expression compared to macrophages from controls. Vimentin is a structural protein in animal cells.

Data from human tissues

Using lung macrophages from subjects with IPF, researchers found that cadmium/carbon black induced citrullination of vimentin, and secretion of cit-vim from lung macrophages was dependent on activation of two enzymes, Akt1 and PAD2. Citrullination is the attachment of the amino acid citrulline onto a protein.

Cit-vim that was isolated and purified from lung macrophages was able to induce invasion of pulmospheres by primary lung fibroblasts from normal subjects. Cit-vim enhanced the expression of collagen by the fibroblasts, and the expression of collagen by lung fibroblasts from IPF subjects was even greater. The pulmospheres -- 3-dimensional spheroids -- were derived from normal lung tissue. Fibroblast proliferation and excessive collagen deposition are part of lung scarring in IPF.

DAMPs are molecules from damaged or dying cells that provoke an innate immune response to clean up the damage. Researchers showed that cit-vim acted as a DAMP to activate fibroblasts through toll-like receptor 4 signaling. The activated fibroblasts produced profibrotic cytokines, contributing to the pathogenesis of IPF.

Thus, the data emphasize a critical role for lung macrophages in the development of lung fibrosis.

Data from mice

In animals, researchers found that mice treated with cit-vim, but not normal vimentin, independently developed lung fibrosis, with architectural destruction and increased collagen deposition, in a toll-like receptor 4-dependent fashion. Wild-type mice exposed to cadmium/carbon black -- but not mouse mutants lacking PAD2 or toll-like receptor 4 -- generated high amounts of cit-vim in plasma and in bronchoalveolar lavage fluid, and the mice developed lung fibrosis.

"This finding is important," Antony said, "because cit-vim is sufficient to provoke fibroblast activation in vitro and elicit profibrotic cytokine/chemokine production and TLR4-dependent lung fibrosis in vivo.

"Our data demonstrate that cadmium/carbon black is a risk factor, not only in subjects with IPF who smoked, but also in nonsmokers. Higher concentrations of cadmium in patients who do not smoke may be caused by exposure to cadmium through food and/or occupation or environment."

A radio telescope located in outback Western Australia has observed a cosmic phenomenon with a striking resemblance to a jellyfish.

Published today in The Astrophysical Journal, an Australian-Italian team used the Murchison Widefield Array (MWA) telescope to observe a cluster of galaxies known as Abell 2877.

Lead author and PhD candidate Torrance Hodgson, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR) in Perth, said the team observed the cluster for 12 hours at five radio frequencies between 87.5 and 215.5 megahertz.

"We looked at the data, and as we turned down the frequency, we saw a ghostly jellyfish-like structure begin to emerge," he said.

"This radio jellyfish holds a world record of sorts. Whilst it's bright at regular FM radio frequencies, at 200 MHz the emission all but disappears.

"No other extragalactic emission like this has been observed to disappear anywhere near so rapidly."

This uniquely steep spectrum has been challenging to explain. "We've had to undertake some cosmic archaeology to understand the ancient background story of the jellyfish," said Hodgson.

"Our working theory is that around 2 billion years ago, a handful of supermassive black holes from multiple galaxies spewed out powerful jets of plasma. This plasma faded, went quiet, and lay dormant.

"Then quite recently, two things happened--the plasma started mixing at the same time as very gentle shock waves passed through the system.

"This has briefly reignited the plasma, lighting up the jellyfish and its tentacles for us to see."

The jellyfish is over a third of the Moon's diameter when observed from Earth, but can only be seen with low-frequency radio telescopes.

"Most radio telescopes can't achieve observations this low due to their design or location," said Hodgson.

The MWA--a precursor to the Square Kilometre Array (SKA)--is located at CSIRO's Murchison Radio-astronomy Observatory in remote Western Australia.

The site has been chosen to host the low-frequency antennas for the SKA, with construction scheduled to begin in less than a year.

Professor Johnston-Hollitt, Mr Hodgson's supervisor and co-author, said the SKA will give us an unparalleled view of the low-frequency Universe.

"The SKA will be thousands of times more sensitive and have much better resolution than the MWA, so there may be many other mysterious radio jellyfish waiting to be discovered once it's operational.

"We're about to build an instrument to make a high resolution, fast frame-rate movie of the evolving radio Universe. It will show us from the first stars and galaxies through to the present day," she said.

"Discoveries like the jellyfish only hint at what's to come, it's an exciting time for anyone seeking answers to fundamental questions about the cosmos."

A recent study shows that lettuce can be grown in greenhouses that filter out wavelengths of light used to generate solar power, demonstrating the feasibility of using see-through solar panels in greenhouses to generate electricity.

"We were a little surprised - there was no real reduction in plant growth or health," says Heike Sederoff, co-corresponding author of the study and a professor of plant biology at North Carolina State University. "It means the idea of integrating transparent solar cells into greenhouses can be done."

Because plants do not use all of the wavelengths of light for photosynthesis, researchers have explored the idea of creating semi-transparent organic solar cells that primarily absorb wavelengths of light that plants don't rely on, and incorporating those solar cells into greenhouses. Earlier work from NC State focused on how much energy solar-powered greenhouses could produce. Depending on the design of the greenhouse, and where it is located, solar cells could make many greenhouses energy neutral - or even allow them to generate more power than they use.

But, until now, it wasn't clear how these semi-transparent solar panels might affect greenhouse crops.

To address the issue, researchers grew crops of red leaf lettuce (Lactuca sativa) in greenhouse chambers for 30 days - from seed to full maturity. The growing conditions, from temperature and water to fertilizer and CO2 concentration, were all constant - except for light.

A control group of lettuces was exposed to the full spectrum of white light. The rest of the lettuces were dived into three experimental groups. Each of those groups was exposed to light through different types of filters that absorbed wavelengths of light equivalent to what different types of semi-transparent solar cells would absorb.

"The total amount of light incident on the filters was the same, but the color composition of that light was different for each of the experimental groups," says Harald Ade, co-corresponding author of the study and the Goodnight Innovation Distinguished Professor of Physics at NC State.

"Specifically, we manipulated the ratio of blue light to red light in all three filters to see how it affected plant growth," Sederoff says.

To determine the effect of removing various wavelengths of light, the researchers assessed a host of plant characteristics. For example, the researchers paid close attention to visible characteristics that are important to growers, grocers and consumers, such as leaf number, leaf size, and how much the lettuces weighed. But they also assessed markers of plant health and nutritional quality, such as how much CO2 the plants absorbed and the levels of various antioxidants.

"Not only did we find no meaningful difference between the control group and the experimental groups, we also didn't find any significant difference between the different filters," says Brendan O'Connor, co-corresponding author of the study and an associate professor of mechanical and aerospace engineering at NC State.

"There is also forthcoming work that delves into greater detail about the ways in which harvesting various wavelengths of light affects biological processes for lettuces, tomatoes and other crops," Sederoff says.

"This is promising for the future of solar-powered greenhouses," Ade says. "Getting growers to use this technology would be a tough argument if there was a loss of productivity. But now it is a simple economic argument about whether the investment in new greenhouse technology would be offset by energy production and savings."

"Based on the number of people who have contacted me about solar-powered greenhouses when we've published previous work in this space, there is a lot of interest from many growers," O'Connor says. "I think that interest is only going to grow. We've seen enough proof-of-concept prototypes to know this technology is feasible in principle, we just need to see a company take the leap and begin producing to scale."

Many athletes, from football players to equestrians, rely on helmets to protect their heads from impacts or falls. However, a loose or improperly fitted helmet could leave them vulnerable to traumatic brain injuries (TBIs), a leading cause of death or disability in the U.S. Now, researchers reporting in ACS Sensors have developed a highly sensitive pressure sensor cap that, when worn under a helmet, could help reveal whether the headgear is a perfect fit.

According to the U.S. Centers for Disease Control and Prevention, 1.6 to 3.8 million sports- and recreation-related TBIs occur each year in the U.S. Field data suggest that loose or improperly fitted helmets can contribute to TBIs, but no devices currently exist that can provide information about how well a helmet conforms to an individual player's head. To help observe and better understand helmet fit, Simin Masihi, Massood Atashbar and colleagues wanted to develop highly sensitive, fabric-based sensors that could map pressure in real-time.

The researchers made their sensors by placing a porous polydimethylsiloxane (PDMS) layer between two fabric-based, conductive electrodes. They created uniform pores in the PDMS layer by mixing and heating PDMS, sodium bicarbonate (also known as baking soda) and nitric acid, which released bubbles of carbon dioxide gas. When the team applied pressure to the sensor, the porous material compressed, causing a capacitance change as the space between the two electrodes decreased. To demonstrate a wearable helmet fit system, the researchers added 16 pressure sensors to different locations on a cap. Three volunteers wore the cap under a football helmet, and the sensors correctly revealed that the person with the largest head measurements felt the most pressure around his head, particularly in the front. The fit cap could help athletes select the proper off-the-shelf helmet for their head and allow manufacturers to develop custom helmets to reduce the severity of sports-related head injuries, the researchers say.

AUSTRALIAN - LED INTERNATIONAL RESEARCH TEAM GENERATES THE FIRST MODEL OF EARLY HUMAN EMBRYOS FROM SKIN CELLS

In a discovery that will revolutionize research into the causes of early miscarriage, infertility and the study of early human development - an international team of scientists led by Monash University in Melbourne, Australia has generated a model of a human embryo from skin cells.

The team, led by Professor Jose Polo, has successfully reprogrammed these fibroblasts or skin cells into a 3-dimensional cellular structure that is morphologically and molecularly similar to human blastocysts. Called iBlastoids, these can be used to model the biology of early human embryos in the laboratory.

The research, published today (TBC) in Nature, was led by Professor Polo, from Monash University's Biomedicine Discovery Institute and the Australian Regenerative Medicine Institute, and includes first authors Dr. Xiaodong (Ethan) Liu and PhD student Jia Ping Tan, as well as the groups of Australian collaborators Dr. Jennifer Zenker, from Monash University and Professor Ryan Lister from the University of Western Australia and international collaborators, Associate Professor Owen Rackham from Duke-National University of Singapore and Professor Amander Clark from UCLA in the United States.

The achievement is a significant breakthrough for the future study of early human development and infertility. To date, the only way to study these first days has been through the use of difficult to obtain, and scarce, blastocysts obtained from IVF procedures.

"iBlastoids will allow scientists to study the very early steps in human development and some of the causes of infertility, congenital diseases and the impact of toxins and viruses on early embryos - without the use of human blastocysts and, importantly, at an unprecedented scale, accelerating our understanding and the development of new therapies," Professor Polo said.

The Polo Lab succeeded in generating the iBlastoids using a technique called "nuclear reprogramming" which allowed them to change the cellular identity of human skin cells that - when placed in a 3D 'jelly' scaffold known as an extracellular matrix - organised into blastocyst-like structures which they named iBlastoids.

iBlastoids model the overall genetics and architecture of human blastocysts, including an inner cell mass-like structure made up of epiblast-like cells, surrounded by an outer layer of trophectoderm-like cells and a cavity resembling the blastocoel.

In human embryos the epiblast goes on to develop into the embryo proper, while the trophectoderm becomes the placenta. However, "iBlastoids are not completely identical to a blastocyst. For example, early blastocysts are enclosed within the zone pellucida, a membrane derived from the egg that interacts with sperm during the fertilisation process and later disappears. As iBlastoids are derived from adult fibroblasts, they do not possess a zona pellucida" he said.

The lead author on the Nature paper, Dr Xiaodong (Ethan) Liu, a post-doctoral researcher in the Polo Lab, said "only when all the data came together and pointed to the same place, we could believe that we had made such a discovery."

Co-first author and PhD student in the Polo Lab, Jia Ping Tan, added: "we are really amazed that skin cells can be reprogrammed into these 3D cellular structures resembling the blastocyst."

The research is published as the International Society for Stem Cell Research is about to release guidelines for research on modelling human embryos in vitro following 2017 and 2018 reports on the generation of mouse "blastoids" in vitro by the UK and Netherland scientists as well as advances in the generation of human stem cells that replicate aspects of early embryonic development. These guidelines are expected at the beginning of this year.

It is not known whether the new guidelines will reference the study published today in Nature, which is the first to produce an integrated stem cell model that closely mimics key fate and spatio-temporal decisions made by the early human embryo. However, in a paper published in Stem Cell Reports last February (2020), the Society states that: "if such models could be developed for the early human embryo, they would have great potential benefits for understanding early human development, for biomedical science, and for reducing the use of animals and human embryos in research. However, guidelines for the ethical conduct of this line of work are at present not well defined."

Although there is no legislative precedent with respect to working with human integrated stem cell models of blastocysts, such as iBlastoids, all experiments had Monash University Human Ethics approval in compliance with Australian law and international guidelines referencing the "primitive streak rule" that states that human blastocysts cannot be cultured beyond the development of the primitive streak, a transient structure that appears at Day 14 in embryonic development.

Under these legislative recommendations, although iBlastoids are different from blastocysts, the Polo Lab did not culture their iBlastoids beyond Day 11 in vitro and they were monitored closely for the appearance of primitive streak-associated genes.

Infertility and miscarriage can be caused by early-stage human embryos failing to implant or failing to progress at the time of implantation. This takes place in the first 2 weeks after conception when women do not even know they are pregnant. These 'silent' miscarriages are likely to represent a significant proportion of the total number of miscarriages that occur and, according to Professor Polo, the generation of iBlastoids provides a model system that will enable insights into this early stage of pregnancy.

Professor Ross Coppel, the Deputy Dean Research of the Faculty of Medicine at Monash University, noted that this discovery will allow the development of improved methods for IVF, the development of protocols for gene therapy of embryos and better and more informative screening methods for new drugs.

"With further research and the right resources, this discovery could open up entirely new industries for Australia and internationally," he said.

Scientists in Japan have observed, and interfered with, the ultrafast motion of electron movement inside of a Xenon atom using the coherent pairs of short light waves in synchrotron radiation. Xenon, consisting of a nucleus surrounded by five nested shells containing a total of 54 electrons, is used in flash lamps, and it burns bright and fast. The luminescent electrons move there on a time scale of one billionth of a second. The fast electron movement is however six orders of magnitude slower than that the scientists observed. Using the synchrotron facility at Institute for Molecular Science, they tracked the electron movement in relaxation to shed energy by dropping from an outer shell to an inner shell. The process happens at a timescale of femtoseconds, or one millionth of a billionth of a second. A femtosecond is to a second as a second is to almost 32 million years. The ability to observe and control such ultrafast processes could open the door to next-generation experiments and applications, according to the researchers.

The results were published on March 17 in Physical Review Letters.

"Controlling and probing the electronic motion in atoms and molecules on their natural time scale of attoseconds -- which are one-thousandth of a femtosecond -- is one of the frontiers in atomic physics and attosecond physics," said paper author Tatsuo Kaneyasu, researcher at the SAGA Light Source, Kyushu Synchrotron Light Research Center in Japan. "In this study, we demonstrated that ultrashort processes in atoms and molecules can be tracked using the ultrashort property of the radiation wave packet."

Recent advances in laser technology enable us to produce ultraquick, or ultrashort, double light pulses that can interact with subatomic processes. This interference can be controlled by precisely tuning the time between each pulse. The pulse excites electrons, the motion of which is referred to as an electron wave packet. Kaneyasu and his team have achieved this technology using synchrotron radiation which has a great advantage in generating higher energy photons than those by lasers.

"This method, termed 'wave packet interferometry,' is now a fundamental tool for studying and manipulating the quantum dynamics of matter," Kaneyasu said. "In this study, the electron wave packet was produced by superimposing some electronic states in a xenon atom."

Much like how two overlapping beams can produce a more intense light than either individually gives off, two overlapping electron wave packets produce quantum effects.

"The ultimate goal is controlling and probing the ultrafast electronic motion of a wide range of elements, not only in the gas-phase atoms and molecules but also in the condensed matters," Kaneyasu said. "This new capability of synchrotron radiation not only helps scientists study ultrafast phenomena in atomic and molecular processes, but may also open up new applications in the development of functional materials and electronic devices in the future."

Cancer develops when changes occur with one or more genes in our cells. A change in a gene is called a fault or a mutation.

The inherited gene mutations found in this study, are passed from parent to child and are common in the population. However, each one individually does not significantly raise cancer risk.

Instead, these mutations collectively act to raise the risk of cancer developing. They do not directly cause cancer, instead they most likely interact with many other risk factors or random mutations that accumulate over a person's lifetime.

Cancers caused by inherited faulty genes were previously thought to be very rare, compared with mutations that happen by chance as we age or other risk factors such a smoking or sunlight.

Further analysis of these genes may help to design more effective early detection and monitoring strategies for the wider population, scientists say.

The findings, published in Cancer Research, a journal of the American Association for Cancer Research, could also aid the development of more effective personalised cancer treatments, as some patients have a different response to treatments depending on their genetics.

Previous research found that, individually, these type of inherited mutations were not responsible for significantly raising cancer risk and they were often excluded from further study.

Yet it's possible that the presence of large numbers of these mutations could heighten cancer risk, as most cases of cancer are caused by mutations in multiple genes.

Researchers at the University of Edinburgh developed a new method, called Bayesian Gene HERitability Analysis (BAGHERA) to estimate if these mutations could collectively increase cancer risk.

The team analysed 38 cancers reported in the UK Biobank - a large-scale biomedical database that contains detailed genetic and health information for half a million people in the UK.

The BAGHERA approach, which groups mutations by the genes they affect, makes it easier to analyse multiple mutations that alone have very subtle effects, but together raise cancer risk.

The results revealed that these collective mutations contribute to the likelihood of developing cancer, including late-onset types such as prostate and bladder cancer.

Many late-onset cancers were not previously thought to be caused by inherited mutations, except in rare cases. They were usually thought to be caused by mutations picked up over many years.

Inherited faulty genes were thought to be very rare and often comprise of a single gene that greatly increases the risk of cancer - such as the BRCA gene which is linked to breast cancer.

They are typically only found in a small number of families and account for a small percentage of all known cancers.

However, the study suggests that in some cases a person's genetic background, the presence of large numbers of these other types of inherited mutations, may also increase cancer risk.

Overall the team identified 1146 genes, called cancer heritability genes (CHGs), that have a contribution to the likelihood of developing cancer during life.

Many of these genes are known to have important roles in the body's defence against cancer - preventing tumours from forming or controlling the transformation from normal to cancer cells.

The team's next step is to undertake further analysis to find out if these genes are connected and how they affect biological pathways that increase cancer risk.

They will also investigate if the genes interact with other risk factors known to increase cancer risk, such as obesity.

Dr Giovanni Stracquadanio, Senior Lecturer in Synthetic Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, said:

"It is reasonable to think that inherited mutations in certain genes can give an advantage to malignant cells to escape the tumour defences in our cells. Integrating genetic information with tumour mutational status can help with tailoring patients' treatment."

BOSTON - Most surgical patients with a history of penicillin allergy can safely be given the guideline-recommended antibiotic cefazolin to prevent infection instead of several penicillin alternatives that are less effective and more expensive, according to a study conducted by Massachusetts General Hospital (MGH), the University of Colorado Anschutz Medical Campus and the University of Porto in Portugal. The researchers reported in JAMA Surgery that the frequency of allergies to both penicillins and cefazolin was so small that most patients should receive cefazolin regardless of their allergy history.

"Under current practice, the roughly 10% of U.S. patients reporting a penicillin allergy are less likely to receive cefazolin at the time of surgery and more likely to receive clindamycin or vancomycin, which increases their risk of developing a surgical infection," says co-first author Kimberly Blumenthal, MD, MSc, an investigator in the Division of Rheumatology, Allergy and Immunology at MGH. "Our study found that the frequency of dual allergies to penicillin and cefazolin was so small - 0.7% - that surgeons and anesthesiologists should feel confident giving cefazolin to nearly all patients with a penicillin allergy history."

More than 17 million surgical procedures are performed each year in the U.S. and, according to the Centers for Disease Control and Prevention, nearly 111,000 result in surgical site infections. Cefazolin, a first-generation cephalosporin, is the guideline-recommended antibiotic for most surgical procedures. Avoidance of cefazolin in patients with penicillin allergy is grounded in research from the 1960s and 1970s that reported a cross-reactivity rate of 8% between penicillins and cephalosporins like cefazolin. In their meta-analysis of 77 studies involving 6,147 patients, investigators conducted the most extensive review to date of the frequency of cross-reactivity, with an eye toward improving the perioperative administration of infection-fighting antibiotics.

"We found that that avoidance of cefazolin based on 50-year-old data is unnecessary and, in many cases, ill-advised," says senior author Meghan Jeffres, PharmD, with the University of Colorado Skaggs School of Pharmacy. "Not only is cefazolin safe for nearly all patients with penicillin allergy, but also, studies have shown that it's well tolerated and has the appropriate spectrum of activity against organisms commonly encountered in surgical site infections."

The study showed that the occurrence of dual allergy between penicillin and cefazolin was higher among patients whose penicillin allergy had been confirmed through testing (3%) compared to those with self-reported penicillin allergy (0.7%). "Many patients have been told by parents that they are allergic to penicillin or have rashes they think are antibiotic-induced, when in fact they're not," explains co-first author Bernardo Sousa-Pinto, MD, PhD, with the University of Porto. "That underscores the need for patients to know their allergy history, to be tested, and to ensure that test results are accurately reflected in their medical records so that physicians can make the best decisions for them when they need surgery."

Jeffres points out that among the chief goals of clinicians and hospital administrators is to keep their surgical site infection rate as low as possible. "Surgeons and anesthesiologists know that the more patients who receive cefazolin, the lower that rate will be," she says. "We believe our study takes a huge step toward providing them with the data and the evidence they need to make well-informed antibiotic decisions for their patients."

A groundbreaking study has given new insights into how copper deposit-forming fluids are transported naturally from their source deep underground towards the Earth's surface.

A team of geologists, led by Lawrence Carter from the University of Exeter's Camborne School of Mines, has published a new theory for how porphyry copper deposits form.

Porphyry deposits provide around 75 per cent of the world's copper which is in increasing demand for electric vehicles, power infrastructure and green technologies such as wind turbines. They originally develop several kilometres below the Earth's surface above large magma chambers. Not only are porphyry deposits rare but most large near-surface examples have already been found. Any new model for how and where they form will be of great interest to mining companies.

In the new study, the researchers have shown that vast quantities of mineralising fluids could be extracted and transported from their source magmas and focussed into the ore-forming environment through 'crystal mush dykes'.

Lawrence Carter, a final year PhD student at Camborne School of Mines, based at the University of Exeter's Penryn Campus said: "Our study addresses the missing link in models for the formation of porphyry-type copper deposits - how vast quantities of mineralising fluids are extracted and transported from their source magmas and focussed into the ore-forming environment.

"In doing so we provide the first field, petrographic and microscale evidence for fluid transport through what we term 'crystal mush dykes'. Their recognition is paramount to the development of more reliable porphyry exploration models and has significance for other ore-forming systems and volcanic processes."

Collaborating with scientists from the British Geological Survey (BGS) and University of Surrey, this research involved field studies and micro-textural and geochemical analyses of samples from the archetypal Yerington porphyry district in Nevada, where an exceptional ~8 km palaeo-vertical cross-section through a number of porphyry copper deposit systems is exposed.

The team were able to identify a wormy interconnected network of quartz within dykes found in rocks that were once beneath the copper deposits. This represents palaeo-porosity in a once permeable magmatic crystal mush of feldspar and quartz. The mush acted as conduits for vast quantities of porphyry-deposit-forming fluids from deep portions of underlying magmas.

It is believed that this breakthrough may provide insights for the discovery of new porphyry copper deposits, and the proposed mechanism key to the formation of other ore deposit types as well as degassing processes in volcanic systems.

High-power laser diode (LD) driven solid-state lighting can generate super-high luminance far exceeding the state-of-art light-emitting diodes (LEDs) source by factors of 2-10, enabling it particularly attractive for automotive headlamp, outdoor lighting, multimedia projectors, laser TVs and so on. Whereas, the thermal shock of laser is extreme, and under intense laser excitation, traditional LEDs phosphor would suffer from luminescence degradation or even failure due to the luminescence saturation. Aiming to overcome this deficiency, highly efficient and stable luminescence bulk phosphors including single crystal, polycrystalline ceramic phosphor and glass ceramic composite phosphor have received enormous attentions. Due to easy fabrication, low cost, mass production and excellent optical properties, luminescent glass ceramics are deemed as the most promising and reliable color converter for high-power laser application.

On the other hand, the routine way for constructing high-power lighting based on"blue laser + yellow-emitting YAG:Ce3+ garnet"is flawed in applications for the lack of red component. However, there is no commercially available red-emitting bulk phosphor, and their explorations remain stagnating, which severely restricts the further developments of high-power lighting.

In a new paper published in Light Science & Application, a team of scientists, led by Professor Zhiguo Xia and Professor Qinyuna Zhang from South China University of Technology, has developed an efficient red-emitting Mg2Al4Si5O18:Eu2+ composite phosphor by using thermal-treatment induced glass structure relaxation and crystallization method, and Professor Lixin Ning from Anhui Normal University performed the theoretical calculation to support the experimental findings. Under 450 nm blue light excitation, intense red emission at 620 nm with high internal/external quantum efficiency of 94.5%/70.6% and high thermal stability was realized. Noteworthy, there are rare reports of fabrication of Eu2+ activated red-emitting glass ceramic phosphor by glass crystallization method. DFT calculations and EXAFS fittings uncover the Eu2+ activators quasi-planar coordinated with 6-oxygens at vacant channel of Mg2Al4Si5O18 crystal. Red-emitting laser-driven device constructed by coupling the phosphor with 445 nm blue laser shows a high laser saturation threshold of 3.25 W mm-2, high luminous flux of 274 lm, and luminous efficiency of 54 lm W-1, which is almost the highest rank among red bulk phosphors. The reported Mg2Al4Si5O18:Eu2+ composite phosphor holds potential for addressing the lack of commercially available all-inorganic red-emitting bulk color converter, and will provide great step towards the advancement of the solid-state lighting technology for new photonic applications.

Solar-induced chlorophyll fluorescence (SIF) is emitted during plant photosynthesis. SIF results from vegetation chlorophyll giving off red and infrared light wavelengths when excited by solar radiation. Measuring SIF is important because it is closely related to the terrestrial gross primary productivity (GPP), which calculates the total amount of carbon dioxide fixed through photosynthesis in a given area. According to many laboratory and field experiments, studies show that SIF can effectively improve estimations of GPP, which is necessary for global carbon sink research and carbon mitigation strategies.

China has committed to carbon neutrality by 2060. Technological upgrades and energy structure adjustments through the next four decades will be vital to reducing carbon emissions. However, the goal is even more attainable considering the large natural carbon sink provided by plants. Expanding the capacity of the terrestrial ecosystem allows natural carbon fixation to provide a more direct and efficient path toward a carbon neutral future. Therefore, scientists must assess the natural carbon sink accurately to evaluate current and forthcoming carbon neutrality implementation plans.

Supported by the Ministry of Science and Technology of China, the Chinese Academy of Sciences, and the China Meteorological Administration, the Chinese Carbon Dioxide Monitoring Satellite Mission (TanSat) was launched in December 2016. TanSat monitors global atmospheric CO2 concentrations and is capable of measuring SIF.

The first TanSat global SIF map was constructed using a data-driven method based on the SVD (singular value decomposition) technique. TanSat now retrieves its SIF product from a new physical-based algorithm named IAPCAS/SIF. This algorithm is based on the Institute of Atmospheric Physics Carbon Dioxide Retrieval Algorithm for Satellite Remote Sensing Platform, which maps global atmospheric CO2 distribution. The IAPCAS/SIF algorithm provides SIF emission data from two micro-windows, 757nm and 771nm, within the O2 A-band.

Due to spatial scale differences, it is difficult to directly verify the accuracy and precision of satellite-measured SIF with SIF measured at the leaf or canopy scale. Much like satellite-based XCO2 products, SIF retrievals still need more comprehensive verification trials that assess precision for further carbon flux estimations.

"The intercomparison between SIF products by different algorithms can verify the reliability of the algorithms, and also provide ideas for subsequent algorithm optimization," said Dongxu Yang, the principal investigator of TanSat mission.

His team compared the TanSat SIF products provided by the new IAPCAS/SIF algorithm and the data-driven (SVD) method. Considering both scale and time, results indicate that the two SIF products agree well on a global extent thought the year. While the team noticed a slight regional bias in the SIF maps, the linear correlations between the two SIF products are strong, higher than 0.73, for all seasons. Their TanSat SIF algorithm comparison is published in Advances in Atmospheric Sciences.

Researchers will analyze and use the new SIF product to better understand the terrestrial ecosystem. This includes assimilating SIF data into GPP modeling and global carbon flux estimations. Optimization of the IAPCAS/SIF algorithm will help to develop SIF products from other satellite missions, and scientists hope that exploring the comprehensive usage of SIF products will promote the quantitive research of the global carbon sink and climate change.

The diesel engine is the backbone of transportation due to its irreplaceability as the primary power source for the freight, navigation and marine engine industries and non-road engineering machinery for the foreseeable future. However, the control of contaminants from fuel combustion has become an urgent global concern. Nitrogen oxides are the primary pollutants from transportation and can contribute to the formation of haze, photochemical smog and acid rain. Selective catalytic reduction of NOx with ammonia (NH3-SCR) technology has been successfully and commercially applied for controlling pollution from diesel vehicle exhaust. The development of efficient and stable NH3-SCR catalysts has been pursued by scientists in the past decades to meet the complicated operating conditions in these vehicles.

Cu-based small-pore zeolites have been demonstrated to be very promising candidates for efficient and stable NH3-SCR catalysts due to their unique structural features and physicochemical properties, e.g., small-pore structure, large cavity, large ion-exchange sites and ligand effect between Cu ions and reactant NH3. As a representative example, Cu-SSZ-13 small-pore zeolite has been commercially utilized to eliminate NOx from diesel vehicles.

In a new overview published in the Beijing-based National Science Review, scientists at Chinese Academy of Sciences, Beijing University of Chemical Technology and Zhejiang University present the latest advances in Cu-based small-pore zeolites applied to the NH3-SCR reaction. They summarize the major advances in Cu-SSZ-13 applied to the NH3-SCR reaction, including the state of copper species, the standard and fast SCR reaction mechanisms, the hydrothermal deactivation mechanism, poisoning resistance and synthetic methodology. They give a valuable summary of new insights on the matching between SCR catalyst design principles and the characteristics of Cu2+-exchanged zeolitic catalysts, highlighting the significant opportunity presented by zeolite-based catalysts. Moreover, more hydrothermally stable Cu-AEI and Cu-LTA zeolites are elaborated as well as other alternative zeolites applied to NH3-SCR. Principles for designing zeolites with excellent NH3-SCR performance and hydrothermal stability are proposed. These scientists likewise outlined the potential development directions of future Cu-based small-pore zeolites.

"In fact, zeolites with small-pore structures and adequate ion-exchange sites have great potential for utilization as NH3-SCR catalysts with high deNOx efficiency and hydrothermal stability," they state from a broader perspective. Development of new types of small-pore zeolites with high SCR activity and hydrothermal stability is still worthwhile based on the design principles proposed in the review, since there is still considerable room in the small-pore zeolite family for researchers to explore.

Electronic organic materials offer promise to support alternative and green energy sources to meet escalating global energy demands and strict environmental regulations. A KAUST-led team has now developed electron-transporting, so-called n-type, organic semiconductors that could help generate electricity from waste heat released by industrial processes and homes.

Thermoelectric generators that can convert temperature changes or gradients into electricity are highly suited for harnessing waste heat. These readily scalable devices are environmentally friendly and do not have any moving parts, which makes them resistant to wear. Their efficiency in energy conversion hinges on minimizing the thermal conductivity of their components while maximizing their electrical conductivity and Seebeck coefficient, a direct measure of their ability to produce a thermoelectric current.

At the heart of thermoelectric generators are two electronically different materials, an n-type semiconductor and a hole-transporting (or p-type) semiconductor, which are joined at their ends to form a circuit. Therefore, the conversion efficiency of the generators depends on both types of semiconductor delivering optimal performance.

Organic thermoelectric materials have recently emerged as easier to process and less toxic than their cheaper and more abundant conventional inorganic counterparts. These new materials also present lower thermal conductivity, but their thermoelectric performance remains inadequate. Typically, doped n-type organic semiconductors are not stable in ambient conditions and display lower electrical conductivities than their p-type equivalents, which have been widely investigated.

"One important challenge is to find n-type organic materials with comparable performance to the best p-type semiconductors," says research scientist, Hu Chen, who led the study within the research group of Iain McCulloch.

The KAUST team devised a systematic approach to synthesize air-stable doped n-type organic semiconductors with high thermoelectric performance. The monomers comprised cyclic amides, or lactams, fused with naphthalene and anthracene cores, generating rigid conjugated polymers by a nontoxic metal-free acid-catalyzed polymerization. "There is no rotational freedom along the backbone, which reduces energetic disorder and subsequently enhances electrical conductivity," McCulloch says.

In this design, the electron withdrawing lactam groups produced a highly electron-deficient backbone, stabilizing the polymer under ambient conditions. Additionally, smaller cores led to larger electron affinity and, consequently, better thermoelectric performance in the polymers, "which had not been so strikingly demonstrated before this work," McCulloch says. Chen explains that larger cores have a lower density of electron withdrawing groups, which cumulatively decrease the electron affinity.

These air-stable polymers have good commercial potential. The team is now planning to develop scalable processes to allow these materials to be integrated into thermoelectric generators.

The use of fossil fuels as energy carriers and raw materials promotes the rapid development of the society. However, the excessive exploitation of fossil fuels gives rise to the energy crisis and undesirable environmental changes. In particular, a continuous increase of CO2 concentration in the atmosphere, which is > 400 ppm today and is estimated to triple by 2040, might result in a series of environmental issues, such as global warming, rising sea levels, and more extreme weather. Therefore, cutting CO2 emissions and developing abundant renewable energy are urgent needs and challenges for our society.

CO2 is not only one of the main greenhouse gases but also an abundant, nontoxic, nonflammable, and renewable C1 resource. Electrochemical conversion of CO2 is an attractive way to recycle CO2 into value-added products and make it possible to store electrical energy in chemical form. As an important component in the electrocatalysis process, the electrolyte interacts with the electrode surfaces, reactants, and intermediates, which plays a key role in charge transport. Different electrolytes have been explored to promote the development of CO2 electrochemical conversion technology.

Ionic liquids (ILs) are organic salts composed of cations and anions with the melting point below 100 ?. Many of them are liquids even at room temperature. ILs have been demonstrated to be the very promising candidate electrolytes for the electrochemical conversion of CO2 due to their unique structural features and physical properties, e.g., high absorption capacity of CO2, high intrinsic ionic conductivity, and wide electrochemical potential widows.

In a new overview published in the Beijing-based National Science Review, scientists at the Institute of Chemistry, Chinese Academy of Sciences in Beijing, China present the latest advances in electrochemical transformation of CO2 into value-added chemicals in IL-based electrolytes. Co-authors Xingxing Tan, Xiaofu Sun, and Buxing Han trace the history of the development of CO2 electrochemical transformation in IL-based electrolytes; they also review representative ILs system, electrocatalysts, and reactor configurations used in CO2 electrochemical transformation.

These scientists likewise outline the potential development directions of IL-based electrolytes for CO2 electrochemical transformation.

"Typically, CO2 electroreduction (CO2ER) and CO2 electroorganic transformation (CO2EOT) are two important routes to convert CO2 into value-added carbonic fuels and chemicals. CO2 electroreduction represents an essential approach for CO2 utilization, in which CO2 could be transformed into many platform chemicals through the construction of C-H bond, such as hydrocarbons, acids, and alcohols. In addition, CO2 can be used as one of the reactants to react with different substrates (e.g., alkenes, alkynes, ketones, epoxides, aziridines, or propargylic amines) to synthesize carboxylic acids, cyclic carbonates, and oxazolidinone derivatives through the construction of C-C, C-O, or C-N bonds," they state in an article titled "Ionic Liquid-Based Electrolytes for CO2 Electroreduction and CO2 Electroorganic Transformation."

"The typical system for CO2ER consists of anode and cathode compartments separated by a proton exchange membrane. Both CO2 reduction reaction and HER take place at the cathode driven by electric energy over the catalyst. CO2EOT is usually performed in undivided cells," they add. "The electrolyte undertakes the role of transporting charge species. Studies have demonstrated that ILs could reduce the initial barrier of CO2 conversion through lowering the formation energy of CO2* - intermediate. Moreover, the competing hydrogen evolution reaction (HER) could be suppressed in the presence of ILs, which might be favorable to improving the selectivity of CO2 conversion."

Syngas was obtained by electrolyzing supercritical CO2 and water in 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6) electrolyte in 2004. The reduction of CO2 to CO with a Faradaic efficiency (FE) of 96% was achieved in an electrocatalytic system with Ag cathode and 18 mol % 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim]BF4) solution electrolyte in 2011, which was marked as an important breakthrough in the development of IL electrolytes for CO2ER.

DMC is almost the most studied product of CO2EOT that involve the use of ILs. "Electrocatalytic fixation of CO2 to epoxides or alcohols to yield organic carbonates via C-O bond formation can avoid the use of toxic phosgene or CO, providing a green and atom economy pathway for the synthesis of organic carbonates," they state.

"Further improvement in the performance of electrochemical conversion of CO2 can be achieved by designing novel functional IL-based electrolytes and exploring innovative electrocatalysts and optimized electrode/reactor configurations. It will also be of great significance to use CO2 as C1 synthon to prepare more diverse chemicals by the construction of different kinds of C-X bonds, like C-Si, C-P, C-S bonds," the scientists forecast.

"The current advancement of electrochemical transformation of CO2 should address the large overpotential, low current density, unsatisfactory product selectivity and yield urgent, especially for value-added C2+ products," they add. "ILs are considered to offer great potential for CO2 conversion technology. Electrochemical transformation of CO2 in IL-based electrolyte is expected to integrate CO2 fixation with renewable electricity storage, providing an avenue to close the anthropogenic carbon cycle."