Mexico reports deadly pig virus in 17 states out of 19 tested

 

(Reuters) - Mexico reported outbreaks of a deadly pig virus in 17 states out of 19 tested, the World Animal Health Organization (OIE) said on Thursday.

Following reports of unusually high mortality, mainly in piglets, in the central-western part of the country, Mexican veterinary officials tested 2,309 samples between August 2013 and May 2014 in farms and slaughterhouses, the Mexican agriculture ministry told the OIE.

These showed that 30 percent were positive for the deadly Porcine Epidemic Diarrhea virus (PEDv), suggesting that there may be some other causative agent involved in this event, the ministry said.

Mexico has 31 states plus the federal district of Mexico.

The country, which has around 16 million pigs, has banned imports of live pigs from the United States since last June, the Mexican ministry said. It added that Mexican authorities had found the virus in 770 dead pigs since it was detected.

The ministry earlier said the infected pigs had been killed.

The virus has killed around 7 million young pigs since it was first identified in the United States almost a year ago, sending pork prices rocketing.

The Mexican states where positive PEDv cases were identified were: Aguascalientes, Baja California, Colima, Federal District, Guanajuato, Guerrero, Jalisco, State of Mexico, Michoacan, Morelos, Nuevo Leon, Puebla, Queretaro, Sinaloa, Sonora, Tlaxcala and Veracruz, the ministry said.

Samples from the States of Yucatan and of Oaxaca were negative for the disease.

The ministry said that, to date, it had not been possible to isolate the virus.

Countries are obliged to report outbreaks of PEDv to the World Animal Health Organization.

(Reporting by Sybille de La Hamaide; Editing by Keiron Henderson and Pravin Char)

New 'T-ray' tech converts light to sound for weapons detection, medical imaging

 

May 22 / 2014

University of Michigan

A device that essentially listens for light waves could help open up the last frontier of the electromagnetic spectrum -- the terahertz range. So-called T-rays, which are light waves too long for human eyes to see, could help airport security guards find chemical and other weapons. They might let doctors image body tissues with less damage to healthy areas. And they could give astronomers new tools to study planets in other solar systems. Those are just a few possible applications.

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Light illustration (conceptual stock image). A device that essentially listens for light waves could help open up the last frontier of the electroma gnetic spectrum -- the terahertz range.

A device that essentially listens for light waves could help open up the last frontier of the electromagnetic spectrum -- the terahertz range.

So-called T-rays, which are light waves too long for human eyes to see, could help airport security guards find chemical and other weapons. They might let doctors image body tissues with less damage to healthy areas. And they could give astronomers new tools to study planets in other solar systems. Those are just a few possible applications.

But because terahertz frequencies fall between the capabilities of the specialized tools presently used to detect light, engineers have yet to efficiently harness them. The U-M researchers demonstrated a unique terahertz detector and imaging system that could bridge this terahertz gap.

"We convert the T-ray light into sound," said Jay Guo, U-M professor of electrical engineering and computer science, mechanical engineering, and macromolecular science and engineering. "Our detector is sensitive, compact and works at room temperature, and we've made it using an unconventional approach."

The sound the detector makes is too high for human ears to hear.

The terahertz gap is a sliver between the microwave and infrared bands of the electromagnetic spectrum -- the range of light's wavelengths and frequencies. That spectrum spans from the longest, low-energy radio waves that can carry songs to our receivers to the shortest, high-energy gamma rays that are released when nuclear bombs explode and radioactive atoms decay.

In between are the microwave frequencies that can cook food or transport cell phone signals, the infrared that enables heat vision technologies, the visible wavelengths that light and color our world, and X-rays that give doctors a window under our skin.

The terahertz band is "scientifically rich," according to Guo and colleagues. But today's detectors either are bulky, need to be kept cold to work or can't operate in real time. That limits their usefulness for applications like weapons and chemical detection and medical imaging and diagnosis, Guo says.

Guo and colleagues invented a special transducer that makes the light-to-sound conversion possible. A transducer turns one form of energy into another. In this case it turns terahertz light into ultrasound waves and then transmits them.

The transducer is made of a mixture of a spongy plastic called polydimethylsiloxane, or PDMS, and carbon nanotubes. Here's how it works:

When the terahertz light hits the transducer, the nanotubes absorb it, turning it into heat. They pass that heat on to the PDMS. The heated PDMS expands, creating an outgoing pressure wave. That's the ultrasound wave. It's more than 1,000 times too high for human ears to pick up.

"There are many ways to detect ultrasound," Guo said. "We transformed a difficult problem into a problem that's already been solved."

Though ultrasound detectors exist -- including those used in medical imaging -- the researchers made their own sensitive one in the form of a microscopic plastic ring known as a microring resonator. The structure measures only a few millimeters in size.

They connected their system to a computer and demonstrated that they could use it to scan and produce an image of an aluminum cross.

The response speed of the new detector is a fraction of a millionth of a second, which Guo says can enable real-time terahertz imaging in many areas.

The system is different from other heat-based terahertz detection systems because it responds to the energy of individual terahertz light pulses, rather than a continuous stream of T-rays. Because of this, it isn't sensitive to variations in the outside temperature, Guo says.

The research is funded by the National Science Foundation and the Air Force Office of Scientific Research.

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Story Source:

The above story is based on materials provided by University of Michigan. Note: Materials may be edited for content and length.

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Journal Reference:

1. Sung-Liang Chen, You-Chia Chang, Cheng Zhang, Jong G. Ok, Tao Ling, Momchil T. Mihnev, Theodore B. Norris, L. Jay Guo. Efficient real-time detection of terahertz pulse radiation based on photoacoustic conversion by carbon nanotube nanocomposite. Nature Photonics, 2014; DOI: 10.1038/nphoton.2014.96

New details on microtubules and how the anti-cancer drug Taxol works

 

May 22 / 2014

DOE/Lawrence Berkeley National Laboratory

Images of microtubule assembly and disassembly have been produced by researchers at the unprecedented resolution of 5 angstroms, providing new insight into the success of the anti-cancer drug Taxol and pointing the way to possible improvements. "This is the first experimental demonstration of the link between nucleotide state and tubulin conformation within the microtubules and, by extension, the relationship between tubulin conformation and the transition from assembled to disassembled microtubule structure," says a biophysicist on the study.

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The most detailed look ever at the assembly and disassembly of microtubules, tiny fibers of tubulin protein that play a crucial role in cell division, provides new insight into the success of the anti-cancer drug Taxol.

A pathway to the design of even more effective versions of the powerful anti-cancer drug Taxol has been opened with the most detailed look ever at the assembly and disassembly of microtubules, tiny fibers of tubulin protein that form the cytoskeletons of living cells and play a crucial role in mitosis. Through a combination of high-resolution cryo-electron microscopy (cryo-EM) and new methodology for image analysis and structure interpretation, researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have produced images of microtubule assembly and disassembly at the unprecedented resolution of 5 angstroms (Å). Among other insights, these observations provide the first explanation of Taxol's success as a cancer chemotherapy agent.

"This is the first experimental demonstration of the link between nucleotide state and tubulin conformation within the microtubules and, by extension, the relationship between tubulin conformation and the transition from assembled to disassembled microtubule structure," says Eva Nogales, a biophysicist with Berkeley Lab's Life Sciences Division who led this research. "We now have a clear understanding of how hydrolysis of guanosine triphosphate (GTP) leads to microtubule destabilization and how Taxol works to inhibit this activity."

Nogales, who is also a professor of biophysics and structural biology at UC Berkeley, as well as an investigator with the Howard Hughes Medical Institute, is the corresponding author of a paper describing this research in the journal Cell. The paper is entitled "High resolution αβ microtubule structures reveal the structural transitions in tubulin upon GTP hydrolysis." Co-authors are Gregory Alushin, Gabriel Lander, Elizabeth Kellogg, Rui Zhang and David Baker.

During mitosis, the process by which a dividing cell duplicates its chromosomes and distributes them between two daughter cells, microtubules disassemble and reform into spindles across which the duplicate sets of chromosomes migrate. For chromosome migration to occur, the microtubules attached to them must disassemble, carrying the chromosomes in the process. The crucial ability of microtubules to transition from a rigid polymerized or "assembled" state to a flexible depolymerized or "disassembled" state -- called "dynamic instability" -- is driven by GTP hydrolysis in the microtubule lattice. Taxol prevents or dramatically slows down the unchecked cell division that is cancer by binding to a microtubule in such a manner as to block the effects of hydrolysis. However, until now the atomic details as to how microtubules transition from polymerized to depolymerized structures and the role that Taxol can play have been sketchy.

"Uncovering the atomic details of the conformational cycle accompanying polymerization, nucleotide hydrolysis, and depolymerization is essential for a complete description of microtubule dynamics," Nogales says. "Such details should significantly aid in improving the potency and selectivity of existing anti-cancer drugs, as well as facilitate the development of novel agents."

To find these details, Nogales, an expert in electron microscopy and image analysis and a leading authority on the structure and dynamics of microtubules, employed cryo-EM, in which protein samples are flash-frozen at liquid nitrogen temperatures to preserve their natural structure. Using an FEI 300 kV Titan cryo-EM from the laboratory of Robert Glaeser, she and her colleagues generated cryo-EM reconstructions of tubulin proteins whose structures were either stabilized by GMPCPP, a GTP analogue, or were unstable and bound to guanosine diphosphate (GDP), or were bound to GDP but stabilized by the presence of Taxol.

The tubulin protein is a heterodimer consisting of alpha (α) and beta (β) monomer subunits. It features two guanine nucleotide binding sites, an "N-site" on the α-tubulin that is buried, and an "E-site" on the β-tubulin that is exposed when the tubulin is depolymerized. Previous microtubule reconstruction studies were unable to distinguish the highly similar α-tubulin and β-tubulin from each other.

"To be able to distinguish the α-tubulin from the β-tubulin, we had to resolve our images at better than 8 Å, which most prior cryo-EM studies were unable to do," Nogales says. "For that, we marked the subunits with kinesin, a protein motor that distinguishes between α- and β-tubulin."

Nogales and her colleagues found that GTP hydrolysis and the release of the phosphate (GTP becomes GDP) leads to a compaction of the E-site and a rearrangement of the α-tubulin monomer that generates a strain on the microtubule that destabilizes its structure. Taxol binding leads to a reversal of this E-site compaction and α-tubulin rearrangement that restores structural stabilization.

"Remarkably, Taxol binding globally reverses the majority of the conformational changes we observe when comparing the GMPCPP and GDP states," Nogales says. "We propose that GTP hydrolysis leads to conformational strain in the microtubule that would be released by bending during depolymerization. This model is consistent with the changes we observe upon taxol binding, which dramatically stabilizes the microtubule lattice. Our analysis supports a model in which microtubule-stabilizing agents like Taxol modulate conformational strain and longitudinal contacts in the microtubule lattice."

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Story Source:

The above story is based on materials provided by DOE/Lawrence Berkeley National Laboratory. The original article was written by Lynn Yarris. Note: Materials may be edited for content and length.

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Journal Reference:

1. Gregory Alushin, Gabriel Lander, Elizabeth Kellogg, Rui Zhang and David Baker. High resolution αβ microtubule structures reveal the structural transitions in tubulin upon GTP hydrolysis. Cell, May 2014

Safe alternatives to BPA: New technology may help identify

 

May 22 / 2014

Cell Press

Numerous studies have linked exposure to bisphenol A (BPA) in plastic, receipt paper, toys, and other products with various health problems from poor growth to cancer, and the FDA has been supporting efforts to find and use alternatives. But are these alternatives safer? Researchers have developed new tests that can classify such compounds' activity with great detail and speed. The advance could offer a fast and cost-effective way to identify safe replacements for BPA.

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Numerous studies have linked exposure to bisphenol A (BPA) in plastic, receipt paper, toys, and other products with various health problems from poor growth to cancer, and the FDA has been supporting efforts to find and use alternatives. But are these alternatives safer? Researchers reporting in the Cell Press journal Chemistry & Biology have developed new tests that can classify such compounds' activity with great detail and speed. The advance could offer a fast and cost-effective way to identify safe replacements for BPA.

Millions of tons of BPA and related compounds are produced each year. "I think it is fair to say that many of these BPA analogs have not been thoroughly tested, yet they are used in everyday plastics such as water bottles, baby bottles, and the lining of canned goods." says lead author Dr. Fabio Stossi of Baylor College of Medicine.

BPA and BPA analogs belong to a class of compounds called endocrine disruptors, so named because they can interfere with the body's endocrine, or hormonal, system. Using their newly developed assays on living cells, Dr. Stossi and his colleagues characterized how 18 different BPA analogs affect alpha and beta estrogen receptors, which are the primary targets of this class of chemicals. Their studies were conducted using high throughput microscopy and automated image analysis in different cell line models, with varying exposures to BPA analogs.

The investigators were able to record and analyze massive data sets related to BPA analogs. "The high throughput approach that we've refined during the past several years can simultaneously quantify what these compounds are doing to a wide range of processes such as protein levels, nuclear trafficking, DNA binding, protein interactions, transcription, cell cycle, and proliferation," says senior author Dr. Michael A. Mancini, of Baylor and the Texas A&M Health Science Center Institute of Biosciences and Technology (IBT). "The results showed us that various BPA analogs increased or decreased certain receptor activities, while others were receptor specific; clearly, the various BPA analogs can have unique properties."

The investigators found that many BPA analogs have inhibitory effects on the beta form of the estrogen receptor, a less well-studied steroid receptor that has tumor fighting properties. Many analogs also acted to stimulate the alpha form of the estrogen receptor or they had mixed inhibitory and stimulatory effects. Determining precisely how these effects influence human health will require additional research. "These studies represent a breakthrough in our ability to focus precious resources on those BPA analogs and other endocrine disrupting chemicals of greatest concern," says coauthor Dr. Cheryl Walker of the IBT.

The scientists note that there are likely many more BPA-like compounds that can be found in products and in the environment. The widely applicable technologies used in the study will enable investigators to rapidly test such compounds for any unexpected or undesirable properties.

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Story Source:

The above story is based on materials provided by Cell Press. Note: Materials may be edited for content and length.

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Journal Reference:

1. Fabio Stossi, Michael J. Bolt, Felicity J. Ashcroft, Jane E. Lamerdin, Jonathan S. Melnick, Reid T. Powell, Radhika D. Dandekar, Maureen G. Mancini, Cheryl L. Walker, John K. Westwick, Michael A. Mancini. Defining Estrogenic Mechanisms of Bisphenol A Analogs through High Throughput Microscopy-Based Contextual Assays. Chemistry & Biology, 2014; DOI: 10.1016/j.chembiol.2014.03.013

Putting a number on opinion dynamics in a population

 

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Opinion formation in a large population is influenced by both endogenous factors, such as interaction with one's peers -- in-person and via social media -- as well as exogenous factors, such as the media, of which mainstream media is one of the most influential factors. For example, according to a study conducted by the National Bureau of Economic Research in 2006, after the introduction and expansion of Fox News in the United States between 1996 and 2000, an estimated 3-28% of the audience was persuaded to vote Republican.

In a recent paper published in the SIAM Journal of Applied Dynamical Systems, authors Anahita Mirtabatabaei, Peng Jia, and Francesco Bullo use a mathematical model to study the process of information assimilation in a population resulting from such exogenous inputs.

"In any modern society, individuals interact to form opinions on various topics, including economic, political, and social aspects," says author Francesco Bullo. "Opinions evolve as a result of the continuous exchange of information among distributed individuals and of the assimilation of information distributed by media."

Developing quantifiable descriptions of societal opinion dynamics allows us to determine the effects of such information distribution. "It is a central question whether the interaction and assimilation process in a population leads to a socially beneficial aggregation of information," Bullo adds. "Models of opinion dynamics in social networks are strongly inspired by distributed dynamical systems observed in statistical mechanics, economics, and biotechnologies."

So how is math used to quantify opinions? "In our investigation, we quantify opinions by real numbers that describe the attitude of an individual in relation to an issue, which is updated by averaging peers' opinions," explains author Anahita Mirtabatabaei. "This method provides a good approximation of the behavior of a large population without relying on detailed social psychological findings."

The model takes into account "bounded confidence," which is the observation that individuals interact only with those whose opinions are close to their own. "An individual only receives information from individuals and media in his or her confidence bound, i.e., with those opinions close enough to his or her own," Mirtabatabaei says. "This idea reflects filter bubbles, a phenomenon in which websites use algorithms to show users only information that agrees with their past viewpoints, as well as selective exposure, a psychological concept broadly defined as individuals' tendency to rely on familiar viewpoints."

The model factors in "partisan resistance," the observation that a voter or decision maker ignores the message from an opposing political predisposition. The authors also take into account the increasing popularity of social media technologies such as blogging and tweeting, which publicly rebroadcast messages with added bias. The variance or discrepancy can represent how much bias is inserted in the rebroadcast, among other things.

"In recent times, the direct influence of the media on the public has been augmented by indirect effects of blogging and social networks," says Mirtabatabaei. "Accordingly we model media influence as a background Gaussian signal input centered on the opinion of an expert." Gaussian functions are widely used in statistics to describe normal distributions; they are used to determine the probability that any observation will fall between two given limits or real numbers. "The variance of this Gaussian input depends on many factors such as message repetition, the expert's importance, public's different interpretation, and blog's rebroadcasting," Mirtabatabaei explains.

The authors also determine the portion of the population that will be attracted to the input's center opinion, referred to as the 'attracted population.'"We establish that the attracted population is an increasing function of a population's confidence bound [how close it is to their opinion] and media input's standard deviation [how much biased rebroadcast of the message occurs] and a decreasing function of the input's measure (how strongly the message is being broadcast by the media). This result suggests that a higher biased rebroadcast of the media's message by various blogs, and/or larger public's confidence bound results in the attraction of a larger population to the advertised message," says Mirtabatabaei.

Further, the study was validated by verifying that it follows known properties of opinion evolution. "We provided a validation of our opinion dynamics model by verifying that their evolutions have basic known properties, such as clustering of opinions [opinion dynamics models have established that people tend to aggregate into groups of equal-minded individuals], social learning that occurs in a social context when sufficient information is available, and manipulation effects caused by misleading input," says Jia.

While the research in the paper corroborates some generally intuitive facts about information assimilation in a society, the authors establish various mathematical properties of the system's dynamics with constant inputs, which can be used to fully understand the input's influence on overall population and on the eventual emergence of opinion clusters. Strategic opinion manipulation through planned information dissemination could be one desired effect. Future directions would involve studying time-dependent inputs and their effects on opinion manipulation vs. constant inputs.

Another direction for future work is the study of multiple inputs of information. "One main future challenge is the study of information assimilation and evolution of public opinions when multiple inputs are considered, for example, when two competing parties debate over their different viewpoints in the mainstream media," says Jia.

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Story Source:

The above story is based on materials provided by Society for Industrial and Applied Mathematics. Note: Materials may be edited for content and length.

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Journal Reference:

1. Anahita Mirtabatabaei, Peng Jia, Francesco Bullo. Eulerian Opinion Dynamics with Bounded Confidence and Exogenous Inputs. SIAM Journal on Applied Dynamical Systems, 2014; 13 (1): 425 DOI: 10.1137/130934040

Drug-target database lets researchers match old drugs to new uses

 

Drug-target database lets researchers match old drugs to new uses

May 22/2014

University of Colorado Denver

There are thousands of drugs that silence many thousands of cancer-causing genetic abnormalities. Some of these drugs are in use now, but many of these drugs are sitting on shelves or could be used beyond the disease for which they were originally approved. Repurposing these drugs depends on matching drugs to targets. A study recently published describes a new database and pattern-matching algorithm that allows researchers to evaluate rational drugs and drug combinations, and also recommends a new drug combination to treat drug-resistant non-small cell lung cancer.

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A study recently published in the journal Bioinformatics describes a new database and pattern-matching algorithm that allows researchers to evaluate rational drugs and drug combinations, and also recommends a new drug combination to treat drug-resistant non-small cell lung cancer.

"Most cancers have more than one genetic alternation. And even genetically targeted drugs tend to affect more than only their stated target. And so the challenge is matching drugs with many effects to cancers with many causes in a way that best maps the drugs' effects onto the intended targets," says Aik Choon Tan, PhD, investigator at the University of Colorado Cancer Center and associate professor of Bioinformatics at the CU School of Medicine.

There are about 500 kinases in the human genome, each of which represents a potentially important drug target. Tan describes the database as a spreadsheet with 500 columns, each column representing a kinase. Heading each row is a drug and then in each column cell is that drug's activity against the kinase.

"Imagine you know a cancer is caused by five kinases acting in unison," Tan says. "Our approach would allow you to query the database for this pattern and discover the drug or combination of drugs that best match the genetic needs."

Because many of these drugs have already earned FDA approval for use in other diseases, the processes of repositioning these drugs for new diseases is much less involved and expensive than if drug developers had started fresh.

Tan and colleagues put the technique to use to recommend drugs that could turn off the kinases that non-small cell lung cancer uses to create resistance existing treatments. It's been an important question -- many lung cancers depend on over-activation of the gene EGFR, but then when EGFR inhibitors like gefitinib or erlotinib are used, the cancers tend to activate other "kinases" that allow the cancer to by-pass around this dependence. Tan and colleagues asked what are these kinases that allow lung cancer to evade gefitinib, and what other drug might turn them off.

The answer may be in the drug bosutinib, developed by Pfizer, which earned FDA approval in 2013 for the treatment of chronic myeloid leukemia. The drug out-competes the body's energy source, ATP, for space in kinases and so keeps them from being activated. And it turns out that bosutinib may inhibit the activity of exactly the kinases that EGFR-dependent lung cancers need to mutate around the challenge of EGFR inhibitors.

In tests on EGFR-dependent lung cancer cell lines, Tan and colleagues show that the drugs gefitinib and bosutinib "showed additive and synergistic effects."

In a mechanism that Tan hopes will become common, his group will now hand off this rational combination to other researchers at the CU Cancer Center and elsewhere who will move the drugs toward a human clinical trial.

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Story Source:

The above story is based on materials provided by University of Colorado Denver. The original article was written by Garth Sundem. Note: Materials may be edited for content and length.

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Journal Reference:

1. J. Kim, V. T. Vasu, R. Mishra, K. R. Singleton, M. Yoo, S. M. Leach, E. Farias-Hesson, R. J. Mason, J. Kang, P. Ramamoorthy, J. A. Kern, L. E. Heasley, J. H. Finigan, A. C. Tan. Bioinformatics-driven discovery of rational combination for overcoming EGFR-mutant lung cancer resistance to EGFR therapy. Bioinformatics, 2014; DOI: 10.1093/bioinformatics/btu323

Medical students may benefit from social media guidance

 

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Medical students use social media extensively, but medical schools may need to offer more guidance in potential pitfalls, according to Penn State College of Medicine researchers.

"We assessed how medical students engage with social media platforms like Facebook and found that they have a pretty sophisticated understanding of its risks and benefits," said Daniel R. George, assistant professor of humanities. He and Dr. Michael J. Green, professor of humanities, conducted two studies that report findings from a survey of 2,109 medical students nationwide.

In the first study, researchers asked students how they and their peers would and should respond to eight hypothetical scenarios involving Facebook. The scenarios focused on ethical issues including privacy, the patient-doctor relationship and relationships with peers.

In one scenario, a student revealed on Facebook that she was caring for a local weatherman. The majority of students, 55 percent, said they should address a peer who violates patient privacy on Facebook. Almost half of the students also indicated that this is what they would actually do. However, 31 percent thought their peers would not do anything to address the situation.

Another hypothetical scenario involved a patient asking a student for medical advice over Facebook. Most students, 61 percent, said that they should explain to the patient that this form of communication is not acceptable. However, 30 percent believed their peers would send a short message with the advice asked.

The researchers reported their findings in AJOB Empirical Bioethics.

Overall, the students seemed to be mindful of the potential dangers of social media use and had a good understanding of how it could be used or misused in a professional context. However, when faced with an ethical dilemma, there was a disconnect between what the students said they would do versus what they thought they should do. Though 39 percent of students said that they should tell a hypothetical peer to remove drunken pictures and foul language from Facebook, 41 percent said they would actually do nothing. Most felt their peers would probably do nothing as well.

Some students promoted strategies for integrating Facebook into future practice, such as sending appointment reminders and relaying public health information to their patient base.

In the words of one student, "If I had a professional Facebook account, (patients) could stay updated on things like schedule changes, get (appointment) reminders, join fundraisers…or stay up to date on public health type information."

"I think some patients would see it as above and beyond if a doctor messaged them to see how they were doing," wrote another. "In this day and age I think a lot of patients might actually appreciate that kind of personal contact from their doctor."

"Students seem to understand the risks of using social media like Facebook, but there is clearly a need for medical schools to help students take the proper course of action," said George.

In the second study, published in BMJ Postgraduate Medical Journal, the researchers examined what students believe about the ways residency programs use Facebook in their admission processes.

Researchers presented students with a hypothetical situation in which a residency admissions committee finds inappropriate pictures on an applicant's Facebook page. The pictures showed the applicant drinking beer and wearing a provocative Halloween costume. Researchers asked students how the admissions committee should respond.

More than 60 percent of students believed that the inappropriate pictures alone should not result in rejection from the residency program, but that the pictures should be considered along with other factors. About a third of the students thought the pictures should have no influence on the application process whatsoever. Less than three percent indicated that the pictures should be grounds for rejection.

However, previous research has found that more than half of the residency programs in the country would reject applicants based on unprofessional Facebook content, such as the inappropriate pictures in the scenario.

"Although most students feel that social media profiles shouldn't affect admission, the reality is that many admissions committees are screening them," said George. "This is another example of how medical schools have an obligation to help educate students to minimize risk."

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Story Source:

The above story is based on materials provided by Penn State. The original article was written by Cara Karper. Note: Materials may be edited for content and length.

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Journal References:

1. Daniel R. George, Anita M. Navarro, Kelly K. Stazyk, Melissa A. Clark, Michael J. Green. Ethical Quandaries and Facebook Use: How Do Medical Students Think They (and Their Peers) Should (and Would) Act? AJOB Empirical Bioethics, 2014; 5 (2): 68 DOI: 10.1080/23294515.2013.864344
2. D. R. George, M. J. Green, A. M. Navarro, K. K. Stazyk, M. A. Clark. Medical student views on the use of Facebook profile screening by residency admissions committees. Postgraduate Medical Journal, 2014; 90 (1063): 251 DOI: 10.1136/postgradmedj-2013-132336

Atomic-level protection for drivers

 

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What takes place at atomic level in a vehicle’s crash-box when we collide? Inga Gudem Ringdalen and her colleagues are providing new knowledge of this topic in order to make cars safer.

A new window on the world of atoms will make future vehicles safer in collisions.

Scientists at SINTEF in Trondheim, Norway, the largest independent research organisation in Scandinavia, have set out on an unusual journey -- into the interior of certain materials. They are about to build a mathematical model of tiny but vital zones in aluminium vehicle bumper systems.

The research group will use this virtual "mini-laboratory" to study the chaos we create when we crash a car. The model will be the first in the world that enables us to perform calculations on these phenomena in aluminium components.

Senior consultant Trond Furu in Hydro, a global aluminium company based in Norway, was involved in commissioning the project, and he has great expectations regarding the model on our behalf too:

"The model will give us new knowledge of how the composition of their component materials affects the properties of aluminium alloys. By linking this knowledge to the expertise of the designers of vehicle components, we can create alloys that will make vehicles safer," says Furu.

Soft "zip fasteners"

The project's focus on aluminium has not come about by accident. Car manufacturers are using aluminium more and more for bumpers in order to reduce the weight of their vehicles, and thus their emissions.

The bumper system lies behind the plastic fascia that most of us call the "bumper." Behind this lie the bumper beams, and behind these a "crash box" that absorbs energy from the impact.

In these aluminium boxes the metal has a granular structure. Each grain is made up of atoms stacked in a highly ordered 3D lattice, all of them with the same spatial orientation.

The grains themselves are extremely strong, but between them are thinner zones that can act something like a zip fastener. It is these that SINTEF is going to examine in detail, because no-one knows how these "zips" behave when we crash.

"Good" disorder

Research scientist and project manager Inga Gudem Ringdalen explains that aluminium atoms are stacked like oranges in a greengrocer's window.

"When you crash, the layers in the stack are displaced, and the disordered state that results differs from one alloy to another. And the faster and further that these irregularities are able to propagate in a collision, the greater are your chances of emerging unscathed from the car. However, until now it has never been possible to calculate phenomena of this sort.

"But how can disorder be a good thing when we collide?"

"In a crash, atoms in vehicle components can be pushed out of their "preferred" positions. The scientific term for such changes of position is "dislocations." If a large number of dislocations occur virtually simultaneously, they can slow each other down, which helps to hold the material together."

"And the stacks of atoms that stay in position; are they not just as useful for ensuring road safety?"

"If atoms are dislocated without meeting a lot of resistance, the result can be that the material will fracture, and the chances of injury increase if parts of a vehicle's structure disintegrate in a crash.

"And why is it so important to know just how much the zip-zones can withstand?"

"Because it is when the "zips" in the metal open that materials come apart."

"The missing link"

Wrecking entire cars and components is an expensive process when a scientist wants to see what happens in a collision, which is why the project team is creating a "virtual laboratory" -- because that is what the mathematical model really is.

NTNU and SINTEF have already come a long way with the same thing in full scale in the SFI SIMLab research centre next door. The centre has developed numerical tools that can simulate how an entire car is affected by a collision.

The automotive industry is already using the results from this large virtual laboratory. According to Ringdalen, the models that will be developed here will provide even better estimates when her project has finalised its modelling software.

"This is because the mechanisms that act at atomic level in the zip-zones have been the "missing link" in every crash model that has been developed for aluminium and other metals," says Inga Gudem Ringdalen.

How the mathematical model will be developed:

• A mathematical model describes reality with the help of equations.
• Important inputs to the model being developed by SINTEF are taken from other models that show how atoms affect their neighbours when aluminium alloys are exposed to extreme loads.
• In order to identify the rules by which layers of atoms react, SINTEF will use a computer program developed by materials scientists at the Lawrence Livermore National Laboratory in the USA.
• The aim of the American program was to describe similar phenomena in other materials. SINTEF will adapt it for use on aluminium alloys.

More than aluminium:

• The mathematical model currently under development at SINTEF will be used in the first place to calculate how aluminium deforms.
• It can later be adapted to perform calculations of deformation in other metals.
• Potential areas of application include the development of "Arctic steel" that will be capable of withstanding extreme cold without becoming brittle, and materials for use in gas and CO₂ pipelines.

Bending helps to control nanomaterials

 

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A new remedy has been found to tackle the difficulty of controlling layered nanomaterials. Control can be improved by simply bending the material.

The mechanism was observed by Academy Research Fellow Pekka Koskinen from the Nanoscience Center of the University of Jyväskylä together with his colleagues from the University of Massachusetts Amherst in the US. Bending decreases interaction between layers, making the material merely a stack of independent atomic layers.

The group investigated the van der Waals nanomaterials which consist of stacked and loosely bound two-dimensional atomic layers. It is experimentally difficult to control the number of layers in the stacks -- and each layer may affect the electric and optical properties of the material dramatically.

- It's as if the apparent color of a stack of papers would change wildly while adding or removing individual sheets, Pekka Koskinen illustrates the situation using a fictitious example.

Bending effectively detaches the layers from each other. The mechanism was observed while investigating layered molybdenum disulphide but it is expected to be valid for the van der Waals materials in general. The results were published in the journal Physical Review Letters.

According to Koskinen, the observation advances research in nanoelectronics and optoelectronics because it markedly simplifies the interpretation and understanding of the electronic and optical properties of layered materials. The research was computational and the found mechanism is still a prediction.

"In nanoscience, experimental and theoretical research advance side by side. This time the prediction came first, and now we eagerly await for an experimental confirmation," Koskinen says.

The research was funded by the Academy of Finland and used the computational resources of the Finnish IT Center for Science (CSC).

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The above story is based on materials provided by Academy of Finland. Note: Materials may be edited for content and length.

Liquid crystal as lubricant

 

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The Stifteverband Science Prize for scientific excellence in Germany was awarded to: Dr. Holger Kretzschmann (Nematel), Werner Stehr and Susanne Beyer-Faiß (Dr. Tillwich GmbH), Dr. Andreas Kailer and Dr. Tobias Amann (Fraunhofer IWM).

Thanks to a new lubricant, small gears can run with virtually no friction. Made from liquid crystalline fluid, these lubricants drastically reduce friction and wear.

Lubricants are used in motors, axels, ventilators and manufacturing machines. Although lubricants are widely used, there have been almost no fundamental innovations for this product in the last twenty years. Together with a consortium, the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg has developed an entirely new class of substance that could change everything: liquid crystalline lubricant. Its chemical makeup sets it apart; although it is a liquid, the molecules display directional properties like crystals do. When two surfaces move in opposite directions, the liquid crystal molecules between the two surfaces align themselves so that the frictional resistance is extremely low. This enables nearly frictionless sliding.

Liquid crystals are known for its use in liquid crystal displays (LCDs) in TV screens, mobile phones or touchscreens. The unusual idea to use them as a lubricant was proposed by Nematel GmbH, which then turned to Fraunhofer IWM to see if it would work. There, Dr. Tobias Amann applied the lubricant made from liquid crystal between two metal workpieces. "Even in the first test, we measured extremely low friction coefficients," remembers Amann.

Match-shaped molecules form a liquid crystalline structure

The researchers at Fraunhofer IWM discovered that liquid crystal is well suited for lubricants because its molecules are long and thin. "When used as a lubricant between two surfaces that slide past each other, the molecules become aligned in parallel to each other in ordered boundary layers," explains Dr. Andreas Kailer, acting director for the Tribology business unit at Fraunhofer IWM. These layers are very stable but slide easily over each other, keeping friction and wear to a minimum.

Still, much was missing before a liquid crystal lubricant suitable for practical applications could be developed. Fraunhofer IWM launched a project along with Nematel GmbH and the lubricant experts at Dr. Tillwich GmbH in 2010, sponsored by the German Federal Ministry of Education and Research (BMBF). Susanne Beyer-Faiß, a chemist at Tillwich, improved the liquid crystal's stability with help from additives. At the same time, her colleague, Werner Stehr, built a special test unit that uses laser technology to enable contact-free measurement of the extremely low friction coefficients. At Fraunhofer IWM, Tobias Amann tested different liquid crystals manufactured by Dr. Holger Kretzschmann at Nematel; among other things, Amann conducted friction experiments with various materials, including iron, copper and ceramic.

He also examined the chemical mechanisms displayed during friction and the effects of mixing different liquid crystal molecules. Tobias Amann deciphered the mechanisms that are responsible for these ultra-low frictional coefficients and discovered how to further optimize the new lubricants in specific ways. He also examined the chemical mechanisms displayed during friction and the effects of mixing different liquid crystal molecules. When the project came to an end, the partners had produced a liquid crystalline lubricant prototype that performed best in sliding bearings made of iron. For this pioneering work, Dr. Tobias Amann, Dr. Andreas Kailer, Susanne Beyer-Faiß, Werner Stehr and Dr. Holger Kretzschmann received the Stifterverband Science Prize, which is awarded every two years for scientific excellence in applied research projects.

Currently, researchers are developing innovative sliding bearings lubricated with liquid crystal for small electric motors for use in the automobile industry, for instance in alternators or windshield wiper motors.

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The above story is based on materials provided by Fraunhofer-Gesellschaft. Note: Materials may be edited for content and length.