#Researchers use oxides to flip graphene conductivity A team of researchers from the University of Pennsylvania;
University of California Berkeley; and University of Illinois at Urbana-Champaign has made inroads in solving one such hurdle.
By demonstrating a new way to change the amount of electrons that reside in a given region within a piece of graphene they have a proof-of-principle in making the fundamental building blocks of semiconductor devices using the 2-D material.
Moreover their method enables this value to be tuned through the application of an electric field meaning graphene circuit elements made in this way could one day be rewired dynamically without physically altering the device.
The study was a collaboration between the groups of Andrew Rappe at Penn Lane Martin at UC Berkeley
and Moonsub Shim at Illinois. It was published in the journal Nature Communications. Silicon is used for making circuit elements
because its charge-carrier density the number of free electrons it contains can be increased easily
or decreased by adding chemical impurities. This doping process results in p-type and n-type semiconductors silicon that has either more positive or more negative charge carriers.
The junctions between p-and n-type semiconductors are the building blocks of electronic devices. Put together in sequence these p-n junctions form transistors which can in turn be combined into integrated circuits microchips and processors.
Chemically doping graphene to achieve p -and n-type version of the material is possible but it means sacrificing some of its unique electrical properties.
A similar effect is possible by applying local voltage changes to the material but manufacturing and placing the necessary electrodes negates the advantages graphene's form factor provides.
We've come up with a non-destructive reversible way of doping Rappe said that doesn't involve any physical changes to the graphene.
The team's technique involves depositing a layer of graphene so it rests on but doesn't bond to a second material:
Applying an electric field pulse can change the sign of the surface charges. That's an unstable situation Rappe said in that the positively charged surface will want to accumulate negative charges and vice versa.
Now if the oxide surface says'I wish I had more negative charge'instead of the oxide gathering ions from the environment
what p-n junctions and complementary circuitry has done for the current state-of-the-art semiconductor electronics. What's even more exciting are the enabling of optoelectronics using graphene
and the possibility of waveguiding lensing and periodically manipulating electrons confined in an atomically thin material.
Their experiments also involved adding a single gate to the device which allowed for its overall carrier density to be tuned further by the application of different voltages.
You could come along with a tip that produces a certain electric field and just by putting it near the oxide you could change its polarity Martin said.
This ability would represent an advantage over chemically doped semiconductors. Once the atomic impurities are mixed into the material to change its carrier density they can't be removed.
#New breast cancer risk prediction model more accurate than current model A new breast cancer risk prediction model combining histologic features of biopsied breast tissue from women with benign breast disease
Results of a Mayo Clinic study comparing the new model to the current standard, the Breast cancer Risk Assessment Tool (BCRAT), are published in the Journal of Clinical Oncology."
"Physicians routinely perform biopsies to evaluate concerning findings in the breast, either felt on exam
or seen on mammogram, for the presence of a breast cancer,"says Amy Degnim, M d.,a surgeon at Mayo Clinic and a senior author of the study."
"However, about three-quarters of these biopsies prove to be benign and are referred to as benign breast disease (BBD)."
"Annually, more than a million American women have a biopsy with a benign finding and are left wondering
if they will later develop breast cancer. Dr. Degnim and her colleagues hypothesized that certain breast tissue findings,
while benign, could help predict which women were increased at risk of developing breast cancer later.""Our new model more accurately classifies a woman's breast cancer risk after a benign biopsy than the BCRAT,
"Dr. Degnim says. Developed by the National Cancer Institute and the National Surgical Adjuvant Breast and Bowel Project, BCRAT is currently the most commonly used model for predicting breast cancer risk in women with BBD.
To test the new model, Dr. Degnim and her colleagues studied a cohort of approximately 10,000 women who had benign breast biopsies at Mayo Clinic
and who received long-term follow-up for a later breast cancer occurrence. Using this cohort researchers determined the age-specific incidence of breast cancer and death,
and 734 matched controls sampled from the Mayo Clinic BBD cohort. They validated the model using an independent set of women from the Mayo BBD cohort (378 patients with a later breast cancer
The BCRAT significantly underpredicted breast cancer risk after benign biopsy (P. 004), whereas predictions derived from the new model were calibrated appropriately to observed cancers (P. 247)."
"Since women with benign breast disease are at higher risk for breast cancer, optimal early detection is extremely important,
"Dr. Degnim says.""Ideally, women at increased risk for breast cancer should be identified so that we can offer appropriate surveillance and prevention strategies.
#Cell imaging gets colorful Campbell has created a new method that converts biochemical processes into color changes that are visualized easily.
This method is a new tool for cell biologists and neuroscientists to use to address questions ranging from fundamental mechanisms in cell biology to the underlying causes of mental illness to the discovery of novel therapeutics.
The results are published in the January 26th issue of Nature Methods. Proteins control essentially all biological processes in a cell
and while they may sometimes act alone proteins most often interact with other proteins to carry out their normal biological functions.
which he has dubbed FPX that employs genetically encoded fluorescent proteins to image dynamic biochemical events in live cells and tissues.
Strategies for converting fluorescent proteins into active biosensors of intracellular biochemistry are few in number and technically challenging comments Campbell.
Dr. Yidan Ding the primary contributor to this work discovered that she could combine the use of both the green
and taking advantage of the fact that green and red fluorescence are mutually exclusive Ding was able to construct a wide variety of biosensors that underwent dramatic changes in fluorescence in response to biochemical processes of interest.
and engineering them to be biosensors that change their color in response to specific biological events Campbell has provided a tool for researchers to immediately pinpoint a major change at the cellular level minimizing the need for extensive biosensor optimization and providing
a versatile new approach to building the next generation of biosensors. This allows for a wide scope of applications notes Campbell.
It will be immediately relevant to many areas of fundamental cell biology research and practical applications such as drug discovery.
Ultimately it will help researchers achieve breakthroughs in a wide variety of areas in the life sciences such as neuroscience diabetes and cancer.
#Treating Cerebral Malaria: New Molecular Target Identified A drug already approved for treating other diseases may be useful as a treatment for cerebral malaria, according to researchers at Harvard T. H. Chan School of Public health.
They discovered a novel link between food intake during the early stages of infection and the outcome of the disease, identifying two molecular pathways that could serve as new targets for treatment."
"We have known for a long time that nutrition can affect the course of infectious disease, but we were surprised at how rapidly a mild reduction in food intake could improve outcome in a mouse malaria model,
"said senior author James Mitchell, associate professor of genetics and complex diseases.""However, the real importance of this work is the identification of unexpected molecular pathways underlying cerebral malaria that we can now target with existing drugs."
"The study appears online January 30, 2015 in Nature Communications. Cerebral malaria--a severe form of the disease--is the most serious consequence of infection by the parasite Plasmodium falciparum,
resulting in seizures, coma, and death. Currently there is a lack of safe treatment options for cerebral malaria, particularly for use in children,
who represent the majority of cases. Even patients who receive early treatment with standard antimalarial chemotherapeutic agents run a high risk of dying,
despite clearance of the parasite. Moreover, around 25%of survivors develop neurological complications and cognitive impairment.
Lead authors Pedro Mejia and J. Humberto Treviño-Villarreal both researchers at Harvard T. H. Chan School of Public health, found that leptin--a hormone secreted from fat tissue with roles in suppressing appetite,
but also in activating adaptive immune and inflammatory responses--is increased upon infection in a mouse model of cerebral malaria,
and turns out to be a major bad actor in promoting neurological symptoms and death. Remarkably, Mejia, Treviño-Villarreal and colleagues showed that reducing leptin using a variety of means,
either genetically, pharmacologically, or nutritionally by reducing food intake during the first two days of infection, protected against cerebral malaria.
The researchers also found that leptin acted primarily on cytotoxic T cells by turning on the well-studied mtor protein
for which pharmacologic inhibitors are readily available. In their animal model, treating mice with the mtor inhibitor rapamycin protected them against the neurological complications of cerebral malaria.
Protection was due in part to a preservation of the blood brain barrier, which prevented the entry of blood cells carrying the parasites into the brain.
As rapamycin is approved already FDA for use in humans, trials in humans for cerebral malaria treatment with this drug may be possible, according to the researchers e
#Hydrogen production in extreme bacterium Researcher at Missouri University of Science and Technology has discovered a bacterium that can produce hydrogen,
an element that one day could lessen the world's dependence on oil. Dr. Melanie Mormile professor of biological sciences at Missouri S&t and her team discovered the bacterium Halanaerobium hydrogeninformans in Soap Lake Washington.
It can produce hydrogen under saline and alkaline conditions in amounts that rival genetically modified organisms Mormile says.
Usually I tend to study the overall microbial ecology of extreme environments but this particular bacterium has caught my attention Mormile says.
I intend to study this isolate in greater detail. Mormile an expert in the microbial ecology of extreme environments wasn't searching for a bacterium that could produce hydrogen
Instead she first became interested in bacteria that could help clean up the environment especially looking at the extremophiles found in Soap Lake.
An extremophile is a microorganism that lives in conditions of extreme temperature acidity alkalinity or chemical concentration.
Living in such a hostile environment Halanaerobium hydrogeninformans has metabolic capabilities under conditions that occur at some contaminated waste sites.
An organic compound 1 3-propenediol can be formulated into industrial products including composites adhesives laminates and coatings It's also a solvent
The infrastructure isn't in place now for hydrogen to replace gasoline as a fuel for planes trains and automobiles.
In her first single-author article Mormile's findings were featured in the Nov 19 edition of Frontiers in Microbiology.
Also named on the patents are Dr. Judy Wall Curators'Professor of Biochemistry and Joint Curators'Professor of Molecular Microbiology & Immunology at the University of Missouri-Columbia and her former lab members Matthew Begemann and Dwayne Elias. A pending patent application submitted along with Elias;
Dr. Oliver Sitton professor of chemical and biochemical engineering at Missouri S&t; and Daniel Roush then a master's student for Mormile is for the conversion of glycerol to 1 3-propanediol also under hostile alkaline and saline conditions.
This patented and patent-pending technology is available for licensing through the Missouri S&t Center for Technology Transfer and Economic Development t
#Researchers identify materials to improve biofuel petroleum processing The University of Minnesota has two patents pending on the research
and hopes to license these technologies. The study was published in the research journal Nature Communications.
Petrochemical and biofuel refineries use materials called zeolites that act as molecular sieves to sort filter and trap chemical compounds as well as catalyze chemical reactions necessary to produce
There are more than 200 known zeolites and hundreds of thousands predicted zeolite variations. The key to improving biofuel and petrochemical processes is to find which zeolites work best.
Unfortunately synthesizing novel zeolites in the lab is complicated a long process that can take many months each.
To analyze all the known and predicted structures would take decades. Instead researchers from the University of Minnesota and Rice university developed a complex computational screening process that can look at thousands of zeolites in the virtual world
and identify their performance for specific applications. This reduces the need for trial and error experimentation in the lab. Using a supercomputer at Argonne National Laboratory we are able to use our computer simulations to compress decades of research in the lab into a total of about a day's worth of computing said lead researcher Ilja
Siepmann a University of Minnesota chemistry professor and director of the U s. Department of energy-funded Nanoporous materials Genome Center based in Minnesota.
Predicting the zeolites'performance required serious computing power efficient computer algorithms and accurate descriptions of the molecular interactions.
The team's software can utilize Mira a supercomputer with nearly 800000 processors to run in a day the equivalent computations requiring about 10 million hours on a single-processor computer.
The computations identified zeolites to attack two complex problems. The first problem researchers tackled is the current multi-step ethanol purification process encountered in biofuel production.
One of the last steps involves the separation of ethanol from water. Researchers found a few all-silica zeolites with superior performance that contain pores
and channels with the ability to accommodate ethanol molecules but to shun hydrogen bonding with water molecules.
One of these zeolites which was synthesized and tested in University of Minnesota chemical engineering and materials science professor Michael Tsapatsis'lab was found to be so effective that it could change the ethanol/water separation process from a multi-step distillation process to a single-step adsorptive process.
Similar zeolitic materials could also have possible applications for separations in the biofuels and petrochemical industry.
The second problem researchers examined targets the upgrading of petroleum compounds into higher-value lubricant and diesel products.
They identified zeolite frameworks that could improve the dewaxing process of transforming linear long-chain into slightly branched hydrocarbon molecules called alkanes
which affect the pour point and viscosity of lubricants and other petroleum products. Researchers say defining appropriate sorbents
and catalysts for all of the complex mixtures involved in creating these products is of paramount importance
what we've achieved here said paper co-author Michael Deem chair of Rice university's Department of Bioengineering and a professor of physics and astronomy y
#Device for guided surgery of deviations in long bones patented CEU-UCH Cardenal Herrera University patented a device that can be applied in surgeries to correct deviations in long bones.
and enables a surgeon to set the cutting angle that best suits the bone, and, also, to set the location
and orientation of holes that accept the future addition of a corrective prosthesis. It enables realigning the body extremity that is operated on
and could have applications in orthopedic surgery on humans. Angular deviations in the bones of body extremities cause physical overload that, in the case of dogs and other animals that develop those bones in the course of only a few months,
can only be corrected through a surgical intervention. After mandatory medical criteria have been met, the device our university patented could have applications in adult humans,
such as to treat fractures and other pathologies that cause this kind of deviations in the bones of adult people.
Mathematical model Luis Doménech, professor of Industrial Design Engineering and Product Development at CEU-UCH, conceived the mathematical model he uses to determine the dimensions a wedge form needs
so that a specific deviated bone can be realigned through surgery. To determine the suitable formula, the bone that is to be operated on is reconstructed first in 3d on the basis of an CT SCAN,
and reproduced in plastic with a 3d printer. Then, using the same procedure the personalized device that the surgeon uses to determine the optimal points
and cutting angles is designed and produced. It takes only two days and a low cost to design the device.
It is fit onto the bone with pressure, another one of the innovations for which this investigation stands out.
The device, patented by CEU-UCH, has so far been used in seven orthopaedic surgical interventions on dogs in which Iván Serra,
professor of Veterinary medicine at the Valencia Catholic University Saint vincent Martyr (UCV), cooperated. These surgeries, which in three dimensions corrected deviations in bones,
yielded some very satisfying results. They are fine examples of translational research in which knowledge transfer from applied investigation to the field of clinical practice was very rapid.
International dissemination of the investigation This new device for surgery of angular deviations in long bones was presented to experts in engineering and veterinary medicine at two international congresses.
CEU-UCH professor Luis Doménech presented the mathematical model used to design the device at the 16th Mathematical Modelling in Engineering and Human Behaviour Conference,
which took place at the Polytechnic University of Valencia in September. The results of the first surgical interventions on dogs were presented
in the presence of UCV professor of Veterinary medicine Iván Serra, at the 17th European Society of Veterinary Orthopaedics and Traumatology Congress,
which was organized by the European Society of Veterinary Orthopaedics and Traumatology (ESVOT) in Venice (Italy) from October 2 to 4
#How cancer turns good cells to the dark side A new computational study by researchers at the Rice-based Center for Theoretical Biological Physics shows how cancer cells take advantage of the system by
which cells communicate with their neighbors as they pass messages to be like me or be not like me.
Led by Rice biophysicists Eshel Ben-Jacob and Jos Onuchic the researchers decode how cancer uses a cell-cell interaction mechanism known as notch signaling to promote metastasis. This mechanism plays a crucial role in embryonic development
and wound healing and is activated when a delta or jagged ligand of one cell interacts with the notch receptor on an adjacent one.
Their open-access study appears this month in the Proceedings of the National Academy of Sciences.
which the researchers mapped the flow of information through genetic circuits involved in cancer metastasis. At the heart of our new understanding is that the primary agents of metastasis are clusters of hybrid epithelial (nonmobile)
These and not the fully mesenchymal cells are the'bad actors'of cancer progression that pose the highest risk.
The multifaceted mechanism by which notch-delta-jagged signaling promotes cancer progression has been a mystery until now Ben-Jacob said
but recent experimental studies have revealed the jagged ligand plays a critical role in tumor progression.
It shows the presence of jagged ligands can give rise to sender/receiver hybrid cells that send a signal--be like
The other (the receiver) expresses low notch and high delta. This situation leads the two cells to adopt opposite fates:
The first clues biologists had to notch-delta signaling came a century ago in studies of the wing formation of fruit flies.
Cancer takes advantage of jagged proteins'influence to form what are essentially migrating units of hybrid cancer stem cells Ben-Jacob said.
Notch-jagged signaling also helps cells develop resistance to chemotherapy and radiotherapy and facilitates metastasis formation by promoting communications between cancer
and stromal (connective tissue) cells at the new locations he said. Recent findings showed stromal cells in the tumor environment secrete jagged ligands.
The Rice researchers found cancer cells hijack nearby stromal cells and prompt them to boost their production of the ligand reinforcing the cancer's chances of survival.
The researchers suggested cells'internal expression of jagged may also increase the production and maintenance of therapy-resistant cancer stem cells.
Because they have a high likelihood to acquire stem-like properties when arriving at distant organs they utilize this cellular plasticity to differentiate
and adapt to new conditions at the metastasis location said lead author Marcelo Boareto a former visiting scholar at Rice and now a doctoral student at the University of Sao paulo Brazil.
Running fuel cells on bacteria Researchers in Norway have succeeded in getting bacteria to power a fuel cell.
and the products of the process are purified water droplets and electricity. This is an environmentally-friendly process for the purification of water derived from industrial processes and suchlike.
It also generates small amounts of electricity--in practice enough to drive a small fan, a sensor or a light-emitting diode.
In the future, the researchers hope to scale up this energy generation to enable the same energy to be used to power the water purification process
which commonly consists of many stages, often involving mechanical and energy-demanding decontamination steps at its outset.
Nature's own generator The biological fuel cell is powered by entirely natural processes--with the help of living microorganisms."
"In simple terms, this type of fuel cell works because the bacteria consume the waste materials found in the water,
The voltage that arises between these particles generates energy that we can exploit. Since the waste in the wastewater (organic material) is consumed and thus removed,
the water itself becomes purified, "he says. Searching for the best bacteria"Our challenge has been to find the mechanisms
but which could also transfer electrons to a metal electrode, "he says. The idea behind this water purification approach was born many years ago
and began discussing how bacteria could be used to generate energy. Since then, they have both been working to put the idea into practice--each from their own respective fields of expertise.
While Netzer is an expert in bacteria, Colmenares is an electrochemist with a knowledge of,
and generate electricity. The wastewater comes from the local Tine dairy and is rich in organic acids,
which are ideal for this process. But this is not essential--other types of wastewater work just as well."
"At the moment, we're not talking about producing large volumes of energy, "says Netzer.""But the process is very interesting
because water purification processes are very energy-demanding using current technology. We're particularly pleased at being able to produce
just as much energy using low-cost materials as others are achieving using much more expensive approaches,
"he says s
#New technique for producing cheaper solar energy suggested by research A team of experts from the University of Exeter has examined new techniques for generating photovoltaic (PV) energy--or ways in
which to convert light into power--more cost efficiently. The global PV market has experienced rapid growth in recent years due to renewable energy targets and CO2 EMISSION controls.
However current widely-used commercial methods employed to generate PV energy such as using silicon or thin film based technologies are still expensive as they are processed through vacuum-based techniques.
The development of technologies and the invention of new materials could lead to the reduction of PV energy generation costs.
Now the team of scientists from Exeter has found that one such material a mineral called perovskite could hold the key to cheaper PV energy generation.
Crucially the team conducted studies with perovskite in Alta Floresta (Brazil) Frenchman Flat (USA) Granada (Spain) Beijing (China) Edinburgh (UK) and Solar Village (Saudi arabia) and confirmed its efficiency
in converting light to power in a range of atmospheric conditions rather than just under direct sunlight.
The research by the team from the Environment and Sustainability Institute (ESI) based at the University of Exeter's Penryn Campus in Cornwall is published in the journal Solar energy Materials & Solar cells.
Professor Tapas Mallick who was involved in the research said: This research offers the potential for significant progress to be made in finding cheaper ways to generate PV energy.
The results which show how perovskite devices work under real operating conditions will lead to our understanding them better
which will benefit industrial-scale production processes. Given concern on large-scale solar farms across the country such techniques will be key to understand how the Perovskite technology integrates within our building envelope.
Dr Senthilarasu Sundaram also from the ESI added: The research is questioning the perovskite material's ability to produce stable solar cells under versatile climatic conditions.
The obtained results are very crucial in terms of perovskite solar cell growth and understanding how to make better devices s
#New breast exam nearly quadruples detection of invasive breast cancers in women with dense breast tissue Molecular Breast Imaging (MBI) is a supplemental imaging technology designed to find tumors that would otherwise be obscured by surrounding dense breast
tissue on a mammogram. Tumors and dense breast tissue can both appear white on a mammogram making tumors indistinguishable from background tissue in women with dense breasts.
About half of all screening-aged women have dense breast tissue according to Deborah Rhodes M d. a Mayo Clinic Breast Clinic physician
and the senior author of this study. MBI increased the detection rate of invasive breast cancers by more than 360 percent when used in addition to regular screening mammography according to the study.
MBI uses small semiconductor-based gamma cameras to image the breast following injection of a radiotracer that tumors absorb avidly.
Unlike conventional breast imaging techniques such as mammography and ultrasound MBI exploits the different behavior of tumors relative to background tissue producing a functional image of the breast that can detect tumors
The study conducted at Mayo Clinic included 1585 women with heterogeneously or extremely dense breasts who underwent an MBI exam at the time of their screening mammogram.
The finding that MBI substantially increases detection rates of invasive cancers in dense breasts without an unacceptably high increase in false positive findings has important implications for breast cancer screening decisions particularly as 20 states now require mammography facilities
and encourage discussion of supplemental screening options says Dr. Rhodes. These findings suggest that MBI has a more favorable balance of additional invasive cancers detected
versus additional biopsies incurred relative to other supplemental screening options. Recent studies have reported supplemental cancer detection rates of 1. 9 per 1000 women screened with automated whole breast ultrasound
and 1. 2 to 2. 8 per 1000 women screened with digital breast tomosynthesis so our finding of an additional 8. 8 cancers per 1000 women makes MBI a very compelling option for women who elect supplemental screening says Dr. Rhodes. Michael O'connor Ph d. a Mayo Clinic scientist
and inventor of the MBI technology calls this latest study a major milestone for both safety
because it incorporates many of the advances in MBI pioneered here at Mayo Clinic and shows that studies can be performed safely with low radiation exposure to the patient says Dr. O'connor. This means MBI is safe and effective as a supplemental screening tool.
what MBI can offer women with dense breasts says Amy Conners M d. chair of Mayo Clinic's Breast Imaging Division
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