#Single atom alloy platinum-copper catalysts cut costs, boost green technology A new generation of platinum-copper catalysts that require very low concentrations of platinum in the form of individual atoms to cleanly
and cheaply perform important chemical reactions is reported today by Tufts University researchers in the journal Nature Communications.
Platinum is used as a catalyst in fuel cells, in automobile converters and in the chemical industry because of its remarkable ability to facilitate a wide range of chemical reactions.
However, its future potential uses are limited significantly by scarcity and cost, as well as the fact that platinum readily binds with carbon monoxide,
which"poisons"the desired reactions, for example in polymer electrolyte membrane (PEM) fuel cells, which are the leading contenders for small-scale and mobile power generation not based on batteries or combustion engines.
The Tufts researchers discovered that dispersing individual, isolated platinum atoms in much less costly copper surfaces can create a highly effective
in order to facilitate downstream polymer production. The current industrial catalyst for butadiene hydrogenation uses palladium and silver.
while a relatively cheap metal, is not nearly as catalytically powerful as platinum, noted Professor of Chemistry Charles Sykes, Ph d.,one of the senior authors on the paper."
"The researchers first conducted surface science experiments to study precisely how platinum and copper metals mix."
"We were excited to find that the platinum metal dissolved in copper, just like sugar in hot coffee, all the way down to single atoms.
We call such materials single atom alloys, "said Sykes. The Tufts chemists used a specialized low temperature scanning tunneling microscope to visualize the single platinum atoms and their interaction with hydrogen."
With that knowledge, Sykes and his fellow chemists turned to long-time Tufts collaborator Maria Flytzani-Stephanopoulos, Ph d.,the Robert and Marcy Haber Endowed Professor in Energy Sustainability at the School of engineering,
They synthesized small quantities of realistic catalysts, such as platinum-copper single atom alloy nanoparticles supported on an alumina substrate,
and then tested them under industrial pressure and temperatures.""To our delight, these catalysts worked very well
and their performance was steady for many days, "said Flytzani-Stephanopoulos.""While we had shown previously that palladium would do related reactions in a closed reactor system,
this work with platinum is our first demonstration of operation in a flow reactor at industrially relevant conditions.
We believe this approach is also applicable to other precious metals if added as minority components in copper."
"Further, the researchers found that the reaction actually became less efficient when they used more platinum,
"Environmental Benefits Because platinum is at the center of many clean energy and green chemicals production technologies, such as fuel cells, catalytic converters,
and value-added chemicals from bio-renewable feedstocks, the new, less expensive platinum-copper catalysts could facilitate broader adoption of such environmentally friendly devices and processes,
The work is the latest fruit from a long cross-disciplinary partnership between Sykes and Flytzani-Stephanopoulos."
In the early 2000s, Maria's group had pioneered the single-atom approach for metals anchored on oxide supports as the exclusive active sites for the water-gas shift reaction to upgrade hydrogen streams for fuel cell use.
Together we embarked on a new direction involving single atom alloys as catalysts for selective hydrogenation reactions.
"Sykes and Flytzani-Stephanopoulos have used this approach to design a variety of single atom alloy catalysts that have,
and properties of single atom alloy surfaces and then applied this knowledge to develop a working catalyst.
Armed with this knowledge, we are now ready to compare the stability of these single atom alloy catalysts to single atom catalysts supported on various oxide or carbon surfaces.
or high risk atherosclerotic plaques--inflamed fatty deposits in the artery wall and a main contributor to cardiovascular disease (CVD).
and causing a heart attack or stroke. CVD remains the leading cause of morbidity and mortality in developed nations,
despite advances in diagnosis and treatment. Atherosclerosis is an important contributor to CVD and varies in severity depending on multiple features that contribute to plaque progression and"stability."
"Using an experimental model, researchers from Boston University School of medicine (BUSM) and the University of California,
Atherosclerosis is a complex disease with many stages, ranging from plaques that can remain clinically silent for decades("stable")to dangerous("vulnerable")plaques.
although few focus on the important clinical endpoint of thrombosis.""Our results showed that the fluorescence ACPP probes were able to distinguish high risk plaques with high sensitivity
"explained corresponding author James Hamilton, Phd, professor of physiology and biophysics and research professor of medicine at BUSM."
This work represents a collaboration by the Hamilton group at BUSM which has pioneered the use of the MRI to identify plaques characterized by multiple vulnerable features,
and a group led by Nobel laureate, Roger Tsein, Phd, from the University of California, San diego that is developing probes to visualize plaques.
Funding for this study was provided by a Boston University Nanomedicine grant and NIH P50hl083801 to James Hamilton and by the Howard hughes medical institute and NIH CA158448 to the Roger Tsien group p
#New drug candidate is promising therapeutic option for angiogenic retinal diseases A research team led by scientists at Beth Israel Deaconess Medical center (BIDMC)
and the University of New mexico School of medicine has identified a small molecule that treats animal models of aged macular degeneration (AMD)
and retinopathy of prematurity (ROP) by preventing the overgrowth of blood vessels that are characteristic of these two retinal diseases.
The new findings, described in today's issue of the journal Science Translational Medicine, show that this molecule,
a discovery that offers a promising alternative to current therapies for these retinal diseases, which require monthly injections of large molecules directly into the eyeball."
"Angiogenesis, the abnormal overgrowth of blood vessels, underlies many severe diseases, and when angiogenesis develops in the eye's retina it causes decreased vision
and can even lead to blindness, "said the study's corresponding author Richard L. Sidman, MD, an investigator in the Department of Neurology at BIDMC and Bullard Professor of Neuropathology (Neuroscience), Emeritus, at Harvard Medical school.
Sidman is a leader in the field of mammalian brain development whose studies have focused on disease mechanisms in mouse neuro-genetic disorders,
including disorders of the retina, the light-sensitive layer of brain tissue at the inner surface of the back of the eye that transmits image information to other parts of the brain via the optic nerve.
AMD develops in approximately 14 million older individuals throughout the U s. This overgrowth of blood vessels damages the photoreceptor cells near the center of the eye's retina,
who develop a similar retinal disease as a side effect of high-level oxygen treatments used until their lungs develop sufficiently to handle the much lower oxygen levels in room air.
MD, Phd, of the University of New mexico, had developed a laboratory screening technique called in vivo phage display
Their results showed that Vasotide led to decreased blood vessel growth in all three models when the agent was administered by either systemic injection,
or through eye drops.""Under normal circumstances, a protein called vascular endothelial growth factor VEGF binds to pertinent endothelial cell receptors lining the blood vessels,
"Although a few other anti-VEGF drugs have been approved for therapy of AMD, they must be delivered directly into the eye through monthly intravitreal injections."
"These treatments are costly, require highly skilled professional execution, and, in rare cases, can cause bleeding
or infection in the eye,"said Sidman. Furthermore, he added, not all patients respond to these agents and, for many patients,
responsiveness decreases after about six months.""In addition to future clinical trials on AMD and ROP, we think that diabetic retinopathy
and certain forms of cancer may also prove to be responsive to Vasotide, "said Sidman."
"This is a very exciting development in that it has the potential to allow the self-administration of a sight-saving drug to patients with AMD,
"said Harold F. Dvorak, MD, Mallinckrodt Distinguished Professor of Pathology at HMS and BIDMC, whose laboratory first identified the VEGF signaling protein nearly 30 years ago o
safe for treatment-resistant autoimmune blood conditions The immunosuppressant sirolimus is an effective and safe steroid-sparing therapy for children and young adults with highly treatment-resistant autoimmune blood conditions,
according to a study published online today in Blood, the Journal of the American Society of Hematology (ASH).
This treatment is particularly effective in children with autoimmune lymphoproliferative syndrome (ALPS), a chronic genetic disorder characterized by the buildup of white blood cells in the organs.
Patients with ALPS and other autoimmune disorders often have immune systems that destroy their body's own healthy blood cells.
The resulting decrease in blood cells causes symptoms such as anemia, uncontrolled bleeding, and infection. Few effective and well-tolerated therapies exist to manage these chronic autoimmune issues.
While standard immunosuppressive therapy with corticosteroids may help some patients, others are resistant, intolerant, or cannot successfully maintain healthy blood cell counts
when they discontinue medication. Recently investigators reported that sirolimus successfully resolved these autoimmune conditions in a small group of children with ALPS without causing adverse side effects."
or white blood cells,"said senior study author David Teachey, MD, of the Children's Hospital of Philadelphia."
as they are associated often with long-term health effects, such as osteoporosis and higher risk of infection."
"To improve disease management for patients with ALPS and similar autoimmune disorders, a research team led by Teachey and his colleague Karen Bride, MD,
Patients received 2 mg/m2 to 2. 5 mg/m2 per day of sirolimus in either liquid or tablet form for six months.
After six months, those who benefited from the drug were allowed to continue treatment with continued follow-up appointments to monitor toxicities.
Based on these findings, the authors propose use of sirolimus as early therapy for patients with these chronic treatment-resistant autoimmune blood conditions
sirolimus should be considered an early therapy option for patients with autoimmune blood disorders requiring ongoing therapy
#New genetic discovery advances understanding of prostate cancer A new and important genetic discovery, which sheds light on how prostate cancers develop
and spread, has been made by an international research team led by scientists at The University of Nottingham.
Prostate cancer is one of the most common cancers affecting men. In the UK about one in eight men will develop it at some point in their lives, with older men and those with a family history of prostate cancer most at risk.
It is not yet possible to accurately distinguish between'indolent'prostate cancers, which need little, if any treatment,
and'aggressive'cancers, which require intensive interventions. Now in new research published in Oncotarget, a multi-disciplinary team at Nottingham, Weill Cornell Medical school,
Lund University in Sweden and Copenhagen University in Denmark, have identified a significant gene called mir137 that is switched off in prostate cancer cells.
Lead researcher at Nottingham, Dr Nigel Mongan said:""With many men continuing to die from metastatic prostate cancer,
there is an urgent need to develop new ways to enable the early identification of aggressive cancers
when such tumours remain localised within the prostate gland when surgery is most effective. We also need to make sure that men with indolent disease do not receive unnecessary treatment
which can lead to urinary continence and sexual dysfunction.""The researchers studied the role of androgens in prostate cancer.
Androgens are important signaling molecules, which play an essential role in men's health by driving the development, repair and regeneration of the prostate and other tissues.
However defective and amplified androgen signaling can trigger prostate cancer and its spread. For this reason, many available prostate cancer treatments are aimed at blocking androgen signaling.
However, resistance to such therapies is a major clinical challenge. The gene identified by the team,
called mir137, is switched off in prostate cancer cells. It functions like a'dimmer switch'in normal cells to reduce androgen signaling.
In prostate cancer where mir137 is switched off, the effect of androgen signaling is increased. Therefore the loss of mir137 leads to enhanced androgen signaling which contributes to prostate cancer initiation and progression.
The study has identified also many new potential targets for the next generation of drugs to treat prostate cancer.
New research is now underway in the Mongan's laboratory at Nottingham to test the effect of various pharmacological treatments in preclinical prostate cancer studies
#Study finds how Alzheimer's-associated protein tangles spread through the brain Massachusetts General Hospital (MGH) investigators have discovered a mechanism behind the spread of neurofibrillary tangles-one of the two hallmarks of Alzheimer's disease-through the brains
of affected individuals. In a report that has been released online in the journal Nature Communications, the research team describes finding that a particular version of the tau protein,
while extremely rare even in the brains of patients with Alzheimer's disease, is able to spread from one neuron to another
and how that process occurs.""It has been postulated that tangles-the abnormal accumulation of tau protein that fills neurons in Alzheimer's disease-can travel from neuron to neuron as the disease progresses,
spreading dysfunction through the brain as the disease progresses. But how that happens has been uncertain,
"says Bradley Hyman, MD, Phd, director of the MGH Alzheimer's disease Research center and senior author of the report."
"Our current study suggests one mechanism at play is that a unique and rare type of tau has the properties we were looking for-it is released from neurons,
taken up by other neurons, transported up and down axons, and then released again.""Previous research has shown that tau tangles first appear in a structure located deep within the brain called the entorhinal cortex,
which is a hub for signals passing between the hippocampus and the cerebral cortex. Tangles appear later in other nearby structures involved with memory and cognition,
Several 2013 studies from Hyman's group and others showed the movement of a mutant form of tau between brain structures and resultant neurodegeneration in a mouse model.
when brain sample from that mouse model were applied to cultured neurons, only 1 percent of the tau in those samples was taken up by the neurons.
the first two containing mouse neurons, connected by microgrooves through which axons-the fibers that carry signals from one neuron to another-can extend.
The team found that applying this rare form of tau from the brains of the mouse model to neurons in the first chamber resulted in the protein's being taken up by those neurons and
within five days, being present at the ends of first-chamber-neuron axons and in neurons in the second chamber.
indicating that once a certain amount of the pathologic version of the protein has been taken up,
and uptake of this form of tau is an important step in the spread of disease from one brain region to another,
"says Hyman, the John Penny Professor of Neurology at Harvard Medical school.""Since that spread likely underlies clinical progression of symptoms,
targeting the mechanisms of the spreading might hold promise to stabilize disease
#Manipulating cell signaling for better muscle function in muscular dystrophy Every heart beat and step in our daily lives is dependent on the integrity of muscles
and the proteins that keep them strong and free of injury as they contract and relax.
Researchers at the University of Michigan Health System have identified a new way of triggering the instructions normally given by the muscle protein dystrophin,
which is found in the muscles used for movement and in cardiac muscle cells. Their study published online ahead of print in PNAS Early Edition suggests a new therapeutic strategy for patients with Duchene muscular dystrophy
a progressive neuromuscular condition, caused by a lack of dystrophin, that usually leaves patients unable to walk on their own by age 10-15.
When dystrophin is missing from the muscle cell, the function of another protein, known as nnos, is impaired,
. and Joanne Garbincius, of the University of Michigan Department of Molecular & Integrative Physiology, found an explanation for this debilitating protein malfunction
"Our work suggests that AMPK signaling may be one of the links between the loss of dystrophin
and the impaired nnos function that is seen in muscular dystrophy, "says Michele, senior study author and professor of molecular & integrative physiology and internal medicine at the University of Michigan."
"AMPK normally helps to turn on nnos function in muscle cells, for instance when we exercise, and when dystrophin is lost,
"AMPK, or AMP-activated protein kinase, coordinates cellular energy use. For the study, the team activated AMPK signaling with drugs that have been used medically to protect heart tissue during surgery
and in sports to enhance performance because of its blood flow boosting abilities. Once AMPK was activated,
the nnos activity that is reduced in muscular dystrophy was restored. The drug worked by bypassing the defective steps in the protein complex pathway,
Still the study is"an important first step to show that manipulating AMPK-nnos signaling at least has the potential to help muscle function in muscular dystrophy"
says Michele whose lab at the University of Michigan Cardiovascular Research center focuses on inherited forms of skeletal and cardiac diseases.
Their work was supported by funding from the Muscular dystrophy Association and the National institutes of health, along with funding from the U-M Cardiovascular Translational Research and Entrepreneurship training program.
Training grants from the NIH and the Cardiovascular Center supported the work of Ph d. candidate Garbincius who helped design the study
and performed the research. Manipulating proteins in the body to compensate for the lack of dystrophin is one of many strategies being investigated to halt
Dilated cardiomyopathy is a leading cause of death for those with DMD. Other researchers have started investigating the possibility that phosphodiesterase inhibitors,
Drugs tested by the U-M appear to correct the signaling pathway that is disrupted in muscular dystrophy at an earlier step than the phosphodiesterase inhibitors s
genetics and disease diagnosis. But carrying out such analyses requires expensive lab equipment, making its application out of reach for many people who live in resource-limited places.
Advances in nanomaterials however, could make analysis of genetic material possible at a much lower cost.
David Sinton and colleagues wanted to see if they could come up with a new paper device with such nanomaterials to test DNA without the use of high-tech facilities.
The researchers made a paper-based diagnostic test out of materials that cost less than $1 per device.
After only a 10-minute run, the device could detect the Hepatitis b virus in blood serum at a level low enough to flag an early-stage acute infection,
and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences.
#Controllable protein gates deliver on-demand permeability in artificial nanovesicles Researchers at the University of Basel have succeeded in building protein gates for artificial nano-vesicles that become transparent only under specific conditions.
The gate responds to certain ph values, triggering a reaction and releasing active agents at the desired location.
Tiny nanovesicles can protect active agents until they arrive in specific environments, such as at the target site in the body.
Cornelia Palivan, researchers from The swiss Nanoscience Institute have developed now a membrane gate that opens on demand.
This means that the enzymes inside a nanocapsule become active under exactly the right conditions
Reacting to changes in ph The gate is made up of the chemically modified membrane protein Ompf,
and substances from the surrounding area can enter the nanocapsule. In the resulting enzymatic reaction, the capsule's contents act on the incoming substrate
Until now, permeability in nanovesicles has been achieved using natural proteins that operate as pores in the protective membrane,
However, fields such as medicine or controlled catalysis call for more precise distribution in order to achieve the greatest possible efficiency of the active agent.
Palivan were able for the first time to integrate a modified membrane protein into an artificially produced nanocapsule, which opened only if it encountered corresponding ph values.
The experiments performed at the university are part of the National Center of Competence in Research Molecular Systems Engineering (NCCR MSE),
and The swiss Nanoscience Institute (SNI
#Chance effect of lab's fluorescent lights leads to discovery An accidental discovery of a"quantum Etch-a-Sketch"that may lead to the next generation of advanced computers
and quantum microchips has been made by team of scientists from Penn State university and the University of Chicago.
The team accidentally has discovered a new way of using beams of light to draw and erase quantum-mechanical circuits on topological insulators, a unique class of materials with intriguing electronic properties.
The research, led by Nitin Samarth, Professor and Downsbrough Head of Physics at Penn State and David D. Awschalom
Liew Family Professor and deputy director in the Institute of Molecular Engineering at the University of Chicago, will be published on October 9, 2015 in Science Advances, the new online journal of the American Association for the Advancement of Science,
The new technique is more flexible than advanced nanofabrication facilities based on chemical processing because it allows for rewritable"optical fabrication"of the topological insulators."
"The electrons in topological insulators have unique quantum properties that many scientists believe will be useful for developing spin-based electronics and quantum computers.
because traditional semiconductor engineering techniques tend to destroy their fragile quantum properties. Even a brief exposure to air can reduce their quality.
In Science Advances, the researchers report the discovery of an optical effect that allows them to"tune"the energy of electrons in these materials using light,
and erase one of the central components of a transistor--the p-n junction--in a topological insulator for the first time.
"said Andrew Yeats, a graduate student in Awschalom's laboratory and the paper's lead author."
and their room lights happened to emit it at just the right wavelength. The electric field from the polarized strontium titanate was leaking into the topological insulator layer,
changing its electronic properties. Awschalom and his colleagues found that, by intentionally focusing beams of light on their samples,
"At Penn State, Samarth said"One exciting aspect of this work is that it's noninvasive.
the team measured their samples in high magnetic fields. They found promising signatures of an effect called weak anti-localization,
"In a way, the most exciting aspect of this work is that it should be applicable to a wide range of nanoscale materials such as complex oxides, graphene,
and transition metal dichalcogenides,"said Awschalom.""It's not just that it's faster and easier.
Researchers grow nanocircuitry with semiconducting graphene nanoribbons In a development that could revolutionize electronic ciruitry, a research team from the University of Wisconsin at Madison (UW)
and the U s. Department of energy's Argonne National Laboratory has confirmed a new way to control the growth paths of graphene nanoribbons on the surface of a germainum crystal.
Germanium is a semiconductor and this method provides a straightforward way to make semiconducting nanoscale circuits from graphene, a form of carbon only one atom thick.
The method was discovered by UW scientists and confirmed in tests at Argonne.""Some researchers have wanted to make transistors out of carbon nanotubes
but the problem is that they grow in all sorts of directions, "said Brian Kiraly of Argonne."
"The innovation here is that you can grow these along circuit paths that works for your tech."
"UW researchers used chemical vapor deposition to grow graphene nanoribbons on germanium crystals. This technique flows a mixture of methane, hydrogen and argon gases into a tube furnace.
it naturally forms nanoribbons with these very smooth, armchair edges,"said Michael Arnold, an associate professor of materials science and engineering at UW-Madison."
"The widths can be very, very narrow and the lengths of the ribbons can be very long,
This high mobility makes the material an ideal candidate for faster, more energy-efficient electronics. However, the semiconductor industry wants to make circuits start
and stop electrons at will via bandgaps, as they do in computer chips. As a semimetal, graphene naturally has no bandgaps,
making it a challenge for widespread industry adoption. Until now. To confirm these findings, UW researchers went to Argonne staff scientists Brian Kiraly and Nathan Guisinger at the Center for Nanoscale Materials,
a DOE Office of Science User Facility located at Argonne.""We have some very unique capabilities here at the Center for Nanoscale Materials,
"said Guisinger.""Not only are designed our facilities to work with all different sorts of materials from metals to oxides,
we can also characterize, grow and synthesize materials.""Using scanning tunneling microscopy, a technique using electrons (instead of light
or the eyes) to see the characteristics of a sample, researchers confirmed the presence of graphene nanoribbons growing on the germanium.
Data gathered from the electron signatures allowed the researchers to create images of the material's dimensions and orientation.
In addition, they were able to determine its band structure and extent to which electrons scattered throughout the material."
"We're looking at fundamental physical properties to verify that it is, in fact, graphene and it shows some characteristic electronic properties,
"What's even more interesting is that these nanoribbons can be made to grow in certain directions on one side of the germanium crystal,
"For use in electronic devices, the semiconductor industry is interested primarily in three faces of a germanium crystal.
where single atoms connect to each other in a diamond-like grid structure, each face of a crystal (1, 1,
1) will have axes that differ from one (1, 1, 0) to the other (1, 0,
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