Overcoming barriers to successful use of autonomous unmanned aircraft

 

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While civil aviation is on the threshold of potentially revolutionary changes with the emergence of increasingly autonomous unmanned aircraft, these new systems pose serious questions about how they will be safely and efficiently integrated into the existing civil aviation structure, says a new report from the National Research Council. The report identifies key barriers and provides a research agenda to aid the orderly incorporation of unmanned and autonomous aircraft into public airspace.

"There is little doubt that over the long run the potential benefits of advanced unmanned aircraft and other increasingly autonomous systems to civil aviation will indeed be great, but there should be equally little doubt that getting there while maintaining the safety and efficiency of the nation's civil aviation system will be no easy matter," said John-Paul Clarke, co-chair of the committee that wrote the report and associate professor of aerospace engineering at the Georgia Institute of Technology.

The report uses the term "increasingly autonomous" systems to describe a spectrum of technologies, from unmanned aircraft that are piloted remotely -- which describes most such aircraft currently in use -- to advanced autonomous systems for unmanned aircraft that would adapt to changing conditions and require little or no human intervention. Increasingly autonomous systems could also be used in crewed aircraft and air traffic management systems to lessen the need for human monitoring and control.

Development of such systems is accelerating, prompted by the promise of a range of applications, such as unmanned aircraft that could be used to dust crops, monitor traffic, or execute dangerous missions currently undertaken by crewed planes, such as fighting forest fires. The FAA currently prohibits commercial use of unmanned aircraft without a waiver or special authorization.

NASA's Aeronautics Research Mission Directorate requested that the Research Council convene a committee to develop a national research agenda for autonomy in civil aviation.

One critical, crosscutting goal that must be achieved before increasingly autonomous aircraft and other systems can reach their full potential is ensuring that they will perform with the high level of safety and reliability expected of civil aviation systems, says the report. It identifies specific technological, regulatory, and other barriers that must be overcome in order to reach that goal.

• Technological barriers include the inherent difficulty associated with characterizing and predicting the behavior of systems that can adapt to changing conditions. This poses a particular challenge in engineering increasingly autonomous unmanned aircraft to be compatible with already-existing air traffic management systems and other elements of the national airspace system. Also, the ability of systems to operate independently of human operators is currently limited by the capabilities of machine sensory, perceptual, and cognitive systems.
• Regulation and certification barriers include the fact that existing processes, criteria, and approaches for certifying aircraft do not adequately address the special characteristics of advanced autonomous systems. In addition, many existing safety standards and requirements, which are focused on ensuring the safety of aircraft passengers and crew, are not well-suited to ensure the safety of unmanned aircraft operations, where the main concern is the safety of people in other aircraft and on the ground.
• Other barriers include social issues, such as public concerns about privacy and safety, and legal hurdles, such as public policy, reflected in law and regulation.
• To help surmount these and other barriers, the report recommends a national research agenda that would involve government agencies, industry, and academia. The committee described eight research projects, considering the following four to be the most urgent and difficult:
• Behavior of adaptive/nondeterministic systems. Technologies that enable aircraft to adapt to uncertain environments and to learn based on experience will be integral to many advanced autonomous aircraft. As autonomous systems take over more functions traditionally performed by humans, there will be a growing need to incorporate autonomous monitoring and other safeguards to ensure that appropriate operational behavior continues. Research is needed to develop new methods and tools to address the inherent uncertainties in airspace system operations due to factors such as weather and conflicting air traffic and thereby enable advanced autonomous systems to improve their performance and provide greater assurance of safety.
• Operation without continuous human oversight. Enabling unmanned aircraft to operate for extended periods of time without real-time human oversight will require that the autonomous systems be able to perform certain critical functions currently provided by humans, such as "detect and avoid" and contingency decision-making. Successful development of these systems and technologies depends on understanding how humans perform their roles currently and how to translate these roles to the autonomous system, particularly for high-risk situations.
• Modeling and simulation. Modeling and simulation capabilities will play an important role in the development of increasingly autonomous systems because they enable researchers, designers, regulators, and operators to get information about how an aircraft -- or one of its systems or components -- performs without actually testing it in real life. For example, computer simulations may be able to test the performance of an autonomous aircraft in millions of scenarios in a short timeframe to produce a statistical basis for determining safety risks. The committee recommended the creation of a distributed suite of modeling and simulation modules developed by disparate organizations with the ability to be interconnected or networked; monolithic modeling efforts that are intended to "do it all" and answer all questions posed tend not to be effective.
• Verification, validation, and certification. The national airspace system's high levels of safety largely reflect the formal requirements imposed by the FAA for verification, validation, and certification of hardware and software and the certification of people as a condition for entry into the system. Extension of these concepts and principles to highly autonomous aircraft and systems is not a simple matter and will require the development of new approaches and tools.

"The barriers we identify and the research agenda we propose to overcome them is a vital next step as we venture into this new era of flight," said committee co-chair John Lauber, a consultant and former senior vice president and chief product safety officer at Airbus.

Research on marijuana's negative health effects summarized in report

 

June 5, 2014

NIH/National Institute on Drug Abuse

The current state of science on the adverse health effects of marijuana use links the drug to several significant adverse effects including addiction, a review reports. The review describes the science establishing that marijuana can be addictive and that this risk for addiction increases for daily or young users. It also offers insights into research on the gateway theory indicating that marijuana use, similar to nicotine and alcohol use, may be associated with an increased vulnerability to other drugs.

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The article, published today in the New England Journal of Medicine, is authored by scientists from the National Institute on Drug Abuse (NIDA), part of the National Institutes of Health.

The review describes the science establishing that marijuana can be addictive and that this risk for addiction increases for daily or young users. It also offers insights into research on the gateway theory indicating that marijuana use, similar to nicotine and alcohol use, may be associated with an increased vulnerability to other drugs.

The authors review literature showing that marijuana impairs driving, increasing the risk of being involved in a car accident and that these risks are further enhanced when combining marijuana with alcohol. The authors also discuss the implications of rising marijuana potencies and note that, because older studies are based on the effects of marijuana containing lower THC -- the main psychoactive chemical found in marijuana -- stronger adverse health effects may occur with today's more potent marijuana.

The reviewers consider areas in which little research has been conducted. This includes possible health consequences of secondhand marijuana smoke; the long-term impact of prenatal marijuana exposure; the therapeutic potential of the individual chemicals found in the marijuana plant; and effects of marijuana legalization policies on public health.

The scientists focus on marijuana's harmful effects on teens, an age group in which the brain rapidly develops, which is one factor that could help explain increased risks from marijuana use in this population. Research suggests that marijuana impairs critical thinking and memory functions during use and that these deficits persist for days after using.

 In addition, a long-term study showed that regular marijuana use in the early teen years lowers IQ into adulthood, even if users stopped smoking marijuana as adults.

The NIDA-supported 2013 Monitoring the Future Survey says that 6.5 percent of 12th graders report daily or near-daily marijuana use, with 60 percent not perceiving that regular marijuana use can be harmful. "It is important to alert the public that using marijuana in the teen years brings health, social, and academic risk," said lead author and NIDA Director Dr. Nora D. Volkow.

 "Physicians in particular can play a role in conveying to families that early marijuana use can interfere with crucial social and developmental milestones and can impair cognitive development."

This review emphasizes that marijuana use is likely to increase as state and local policies move toward legalizing marijuana for medical or recreational purposes. As use increases, so might the number of people likely to suffer negative health consequences, the review says.

For more information on marijuana and its health consequences, go to: www.drugabuse.gov/publications/drugfacts/marijuana.

Molecular secret of short, intense workouts clarified

 

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In the last few years, the benefits of short, intense workouts have been extolled by both researchers and exercise fans as something of a metabolic panacea capable of providing greater overall fitness, better blood sugar control and weight reduction -- all of it in periods as short as seven minutes a few times a week.

Now, in a new study, scientists from the Florida campus of The Scripps Research Institute (TSRI) confirm that there is something molecularly unique about intense exercise: the activation of a single protein.

The study, published recently by The EMBO Journal, revealed the effects of a protein known as CRTC2.

The scientists were able to show that following high-intensity exercise, which enlists the sympathetic nervous system's "fight or flight" response, CRTC2 integrates signals from two different pathways -- the adrenaline pathway and the calcium pathway, to direct muscle adaptation and growth only in the contracting muscle.

Using mice genetically modified to conditionally express CRTC2, the scientists showed that molecular changes occurred that emulated exercised muscles in the absence of exercise.

"The sympathetic nervous system gets turned on during intense exercise, but many had believed it wasn't specific enough to drive specific adaptations in exercised muscle," said Michael Conkright, PhD, a TSRI assistant professor who led the study. "Our findings show that not only does it target those specific muscles, but it improves them -- the long-term benefits correlate with the intensity of the workout."

Mobilizing Resources

In the genetically altered animal models, this resulted in a muscle size increase of approximately 15 percent. Metabolic parameters, indicating the amount of fuel available to the muscles, also increased substantially -- triglycerides went up 48 percent, while glycogen supplies rose by a startling 121 percent.

In an exercise stress test, the genetically altered animals improved 103 percent after the gene was activated, compared to an 8.5-percent improvement in normal animals.

"If you think of the adrenaline system as something that mobilizes resources when you encounter, say, a bear on your way to work, what we found is that the system also gets you ready for your next bear encounter," Conkright said.

The new findings open the door to a range of potential exercise enhancements.

"Nothing can supplant exercise; however, just by activating one protein, we clearly improved performance in animal models," said Staff Scientist Nelson E. Bruno, MD, PhD, the first author of the study and a member of the Conkright laboratory. "We are now searching for molecular therapeutics that will activate the CRTC2 protein so that even an average exercise routine could potentially be enhanced and made more beneficial.

Interactive teaching methods help students master tricky calculus

 

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Pre-class assignments, small group discussions and clicker quizzes improve students' ability to grasp tricky first-year calculus concepts, according to a new study by UBC researchers.

Students taught in such active-engagement classes were 10 per cent more likely to understand key concepts on subsequent quizzes, according to the study published in The International Journal on Mathematics Education. This was true even when compared to students in classes already incorporating modest levels of clicker use and interactive discussion. They were also better able to apply their knowledge to new ideas.

"With the right support, you don't need a great deal of instructional experience to introduce the techniques," said UBC mathematician and educational strategist Warren Code, lead author of the paper.

As part of UBC's ongoing efforts to improve undergraduate teaching and learning, Code and colleagues selected two especially difficult topics covered in large first-year calculus classes, and designed week-long 'teaching interventions' to more actively engage students. They then measured the impact on student comprehension of the tricky topics using quizzes and mid-term exams.

The study compared the performance of two sections, a total of 350 students. The demographics, attitudes and math background of both sections were similar. Each student was only exposed to enhanced active teaching methods for one of the two topics.

"You can't replicate perfect lab conditions in the classroom," says Code. "But we designed the observations so students acted as their own control, and each section outperformed the other on the topic for which it received the intervention. So to the degree possible, we're comparing apples to apples."

Short nanotubes target pancreatic cancer

 

June 5, 2014

Rice University

Short, customized carbon nanotubes have the potential to deliver drugs to pancreatic cancer cells and destroy them from within, according to researchers. Pristine nanotubes produced through a new process can be modified to carry drugs to tumors through gaps in blood-vessel walls that larger particles cannot fit through. The nanotubes may then target and infiltrate the cancerous cells' nuclei, where the drugs can be released through sonication -- that is, by shaking them.

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Short, customized carbon nanotubes have the potential to deliver drugs to pancreatic cancer cells and destroy them from within, according to researchers at Rice University and the University of Texas MD Anderson Cancer Center.

Pristine nanotubes produced through a new process developed at Rice can be modified to carry drugs to tumors through gaps in blood-vessel walls that larger particles cannot fit through.

The nanotubes may then target and infiltrate the cancerous cells' nuclei, where the drugs can be released through sonication -- that is, by shaking them.

The research led by Rice chemist Andrew Barron was reported in the Royal Society of Chemistry's Journal of Materials Chemistry B.

Most pancreatic cancer patients die within a year of diagnosis and have a five-year survival rate of 6 percent, partially because there is no method for early detection, according to the American Cancer Society. Tumors are often inoperable and pancreatic cancer cells are also difficult to reach with chemotherapy, said co-author Jason Fleming, a professor of surgical oncology at MD Anderson.

"These findings are encouraging because they offer a potential delivery solution for pancreatic cancer patients whose tumors resist standard chemotherapy," Fleming said. "There are molecular and biological barriers to efficient delivery of chemotherapy to pancreatic cancer tumors, and these nanotubes might be able to make some of those irrelevant."

Rice scientists made nanotubes pure enough to modify for the purpose and small enough to squeeze through the body's defenses, Barron said. The researchers knew from previous work that nanotubes could be modified -- a process called functionalization -- to carry chemotherapy agents and release them at a controlled rate through sonication.

"This time, we were trying to work out how long the tubes should be and the extent of functionalization to maximize uptake by the cells," Barron said.

Several discoveries were key, he said. First, Rice graduate student, alumnus and co-author Alvin Orbaek purified the carbon nanotubes of iron catalysts necessary to their growth by flushing them with chlorine. "Leftover iron particles damage the tubes through oxidation," Barron said. "That makes subsequent use difficult."

The next step was to cut the nanotubes down to size. Very long nanotubes are floppy and hard to deal with, Barron said. Enrico Andreoli, a postdoctoral research associate in Barron's group and lead author of the paper, used a thermal process to chop them to an average length of 50 nanometers. (A human hair is about 100,000 nanometers wide.)

"Instead of ending up with a fluffy nanotube powder, we get something that looks like a hockey puck," Barron said. "It's not dense -- it looks like a spongy puck -- but you can cut it with a razor blade. You can weigh it and do accurate chemistry with it."

Barron's lab added polyethyleneimine (PEI) to the nanotube surfaces. In lab tests, the modified tubes were easily dispersed in liquid and able to pass through barriers into live cancer cells to infiltrate the nuclei. A small-molecule variant of PEI proved to be less toxic to cells than larger versions, Barron said.

"This research shows that the particles are small enough to get inside cells where you like them to be and that they may have an increased killing advantage -- but that's still unknown," Fleming said.

Fleming, whose work focuses on improving drug delivery for pancreatic cancer, cautioned that more research is required. "The next step will be to test this approach in mice that have allografts taken from human tumors," he said. "The architecture of these tumors will more closely resemble that of human pancreatic cancer."

Demographics drive fitness partner decisions online, study finds

 

June 5, 2014

University of Pennsylvania

Participants in an online fitness program ignored the fitness aptitude of their potential partners, instead choosing partners based on age, gender and BMI. The findings suggest that although people in online health programs are beckoned with the possibilities of meeting healthier people who can provide them with information about new kinds of exercises and better strategies for getting healthy, they self-select into networks that look very similar to the kinds of networks that people typically have offline.

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Who would you rather have as a fitness partner: a paragon of athleticism and dedication who could motivate you to exceed your current level of fitness or an equal, with whom you could exchange tips and encouragement on the road to better health?

Or neither? According to a new study led by University of Pennsylvania's Damon Centola, participants in an online fitness program ignored the fitness aptitude of their potential partners.

"Instead they chose contacts based on characteristics that would largely be observable in regular, offline face-to-face networks: age, gender and body mass index," Centola said.

As more people turn to the Internet to help them improve their health and fitness, Centola, an associate professor in the Annenberg School for Communication, wanted to examine how people sought out health partners in an online forum. He coauthored the study with Arnout van de Rijt, an associate professor in Stony Brook University's Department of Sociology. The paper was published online in the journal Social Science and Medicine.

Centola and van de Rijt partnered with an existing online fitness website to recruit 432 participants to be part of their new "Health Improvement Network." All of the participants shared ten pieces of information: their age, gender, ethnicity, body mass index (BMI), fitness level, diet preferences, goals for the program and favorite exercise, as well as their average exercise minutes and intensity level.

The researchers divided the participants into six groups. Each participant was then randomly partnered with six "health contacts" in their group with whom they could exchange information. Over a five-week period, the participants were given the opportunity to select new health contacts and drop existing ones. The only information on which they had to base their choice was the set of ten characteristics that the other members of the group had shared. Participants had no knowledge of who each other's health contacts were, or whether there were any "highly connected" individuals. This allowed the study to reveal which characteristics participants would use to make their connections.

The researchers anticipated that group members would select health contacts who shared similar exercise routines or interests, or even fitness "leaders" who were very fit and could serve as motivational role models. Yet in five of the six communities, participants did neither. Rather, the community members showed a strong inclination to choose contacts whose age, BMI and gender were like their own.

The participants' tendency to "make ties to 'the devil they know,'" the authors wrote, "may unintentionally limit their opportunities for finding health information from sources that they are not normally exposed to."

The findings suggest that although people in online health programs are beckoned with the possibilities of meeting healthier people who can provide them with information about new kinds of exercises and better strategies for getting healthy, they self-select into networks that look very similar to the kinds of networks that people typically have offline: people with similar age, gender and BMI profiles as themselves.

Health programs can work around this human tendency, Centola noted, by actively recommending "health buddies" based on characteristics that are hard to connect to offline, but easy to find online, such as people who are good motivational partners, or partners who prefer similar exercises, or are working to increase their endurance to similar levels.

"Our findings suggest that the trick to an information-rich online community," Centola said, "is to encourage new kinds of ties by reminding participants just how valuable these online relationships can be."

New targets that could increase effectiveness, reduce side effects in breast cancer treatments

 

June 5, 2014

Scripps Research Institute

New targets for potential intervention in breast cancer have been identified by researchers. These new targets could eventually increase effectiveness and reduce the undesirable side effects associated with current treatments. In addition to exploring potential new drugs for breast cancer, the researchers also hope to investigate the implications for prostate cancer, another hormone-driven disease.

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Scientists from the Florida campus of The Scripps Research Institute (TSRI) have found new targets for potential intervention in breast cancer. These new targets could eventually increase effectiveness and reduce the undesirable side effects associated with current treatments.

The study was published online ahead of print on June 5, 2014 by the journal Structure.

Approximately two out of three breast cancers are driven by receptors that bind the hormones estrogen and estrogen —when the hormones bind to these receptors in cancer cells, they signal the cancer cells to grow. What makes the progesterone receptor therapeutically interesting is that it has two activation domains—AF1 and AF2. Normally, both are needed for full activation of the receptor.

“Using hydrogen-deuterium exchange technology, our study pinpoints just how AF2 communicates with AF1—the first evidence of the long-range interaction between these two functional domains,” said Patrick R. Griffin, a TSRI professor who led the study. “These findings support further research to look for promising small molecules that block that interaction.”

The findings are especially important because in some mutations AF2 is deleted, yet the receptor still drives the cancer using its AF1 domain. Current drugs used for treating these cancers only target the AF2 domain, so with nothing to bind to, they do not work at all. While several studies have shown the importance of AF1, its binding domain is remarkably dynamic, frequently shifting shape and making it difficult to target with drugs.

In the new study, the scientists used an advanced technology known as hydrogen-deuterium exchange mass spectrometry (HDX) to measure the intricate interactions between the AF1 and AF2 domains of the progesterone receptor.

HDX mass spectrometry is a high-precision, high-sensitivity mapping technique that enabled the scientists to determine the specific regions of the receptor that are altered upon interaction. This information was used to infer structural changes that result from the interaction and to probe the conformational flexibility of intact multidomain proteins.

In addition to exploring potential new drugs for breast cancer, the researchers also hope to investigate the implications for prostate cancer, another hormone-driven disease.

“Many features of the androgen receptor are similar to progesterone receptor, as they belong to the same subfamily of steroid receptors,” said Devrishi Goswami, the first author of the study and a member of the Griffin laboratory. “It could work the very same way. So these new insights may also help in finding new approaches to treating hormone-therapy-resistant prostate cancer.”

Detida advogada que tinha relações com detentos para roubá-los

 

 

 

.Eu nem irei postar a íntegra desta notícia por ser até nauseante. Além do que menciona o título da postagem, a mulher mandou executar um casal.

Eu não entendo como uma ordinária dessas consegue obter um diploma de advogada.

Bem, não só ela, mas uma multidão de falsos bacharéis proliferam no mundo inteiro.

Até onde as Faculdades são responsáveis por tudo isso?

Até onde os governos, as Câmaras dos Deputados, os Senados Federais são responsáveis por essa cambada de doentes mentais que não se sabe como, conseguem obter um diploma de nível superior ?

Mas já aconteceu que alguém com muita fome rouba qualquer coisa de um supermercado e é preso e condenado. Nesta altura da minha revolta eu diria que neste mundo, em muitos aspectos, Nem com Deus.

How do phytoplankton survive scarcity of critical nutrient?

 

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To conduct their work, the scientists collected water samples at different depths of the ocean during two cruises from the relatively nutrient-rich waters off Woods Hole to the phosphorus-starved subtropical Sargasso Sea near Bermuda in 2008 and 2012. Pictured here are corresponding author WHOI Associate Scientist Benjamin Van Mooy (orange helmet) and research assistant Justin Ossolinski (blue helmet) working with crew members of the R/V Knorr to deploy a sediment net-trap used in the study.

Phytoplankton -- tiny, photosynthetic organisms -- are essential to life on Earth, supplying us with roughly half the oxygen we breathe. Like all other life forms, phytoplankton require the element phosphorus to carry out critical cellular activity, but in some parts of the world's ocean, P is in limited supply. How do phytoplankton survive when phosphorus is difficult to find?

Phytoplankton can alter their biochemical make-up according to the availability of nutrients in the water. When phosphorus (P) is particularly abundant in the water, phytoplankton produce and store a form of P called polyphosphate, or poly-P, to use later during times when P is less abundant. The accepted wisdom has been that poly-P was would be found stored by micro-organisms in waters where P was abundant and would be scarce in waters depleted of P. But when a group of researchers from the Woods Hole Oceanographic Institution (WHOI) and the Bigelow Laboratory for Ocean Sciences tested that notion, conducting the most comprehensive survey of poly-P content and distribution in the western North Atlantic, what they found was surprising.

Rather than finding low levels of poly-P in the phytoplankton in the Sargasso Sea where P is scarce, they found the phytoplankton were enriched with poly-P when compared to those in the nutrient rich waters in the western North Atlantic -- the opposite of what they had expected. They also found that in low-P environments, poly-P was more readily recycled from sinking particles, retaining it in shallower waters where phytoplankton live and making it available for their use.

"We've know that Poly-P existed in phytoplankton for a very long time. The conventional wisdom that phytoplankton made more Poly-P when they had more phosphorus just made so much intuitive sense that few people have worked on this molecule," said WHOI marine chemist Ben Van Moy, the corresponding author on the study. "However, there were a few hints in the literature that the whole story on poly-P was not completely wrapped up. We certainly didn't set out thinking that we might upend current thinking, and it took us a long time before we would believe our own results. I think the larger message from fundamental discoveries like this is that we have so much more to learn about phosphorus and how phytoplankton deal with its scarcity in certain regions of the sea. Hopefully this paper will be a launching point for a lot of exciting science."

Mobile DNA test for HIV under development

 

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Rice graduate students Zachary Crannell, left, and Brittany Rohrman are leading Rice University bioengineers in an effort to develop an efficient test to detect signs of HIV and its progress in patients in low-resource settings.

Rice University bioengineers are developing a simple, highly accurate test to detect signs of HIV and its progress in patients in resource-poor settings.

The current gold standard to diagnose HIV in infants and to monitor viral load depends on lab equipment and technical expertise generally available only in clinics, said Rice bioengineer Rebecca Richards-Kortum. The new research features a nucleic acid-based test that can be performed at the site of care.

Richards-Kortum, director of the Rice 360˚: Institute for Global Health Technologies, and her colleagues reported their results in the American Chemical Society journal Analytical Chemistry.

The proof-of-concept work by co-lead authors Zachary Crannell and Brittany Rohrman, both graduate students in the Richards-Kortum lab, follows their similar technique to detect the parasite that causes the diarrheal disease cryptosporidiosis, reported earlier this year.

The new technique would replace a complex lab procedure based on polymerase chain reaction with one that relies on recombinase polymerase amplification (RPA), a method to quickly amplify -- that is, multiply -- genetic markers found in blood to levels where they can be easily counted. In a test the team calls qRPA, a specific sequence in HIV DNA is targeted and tagged with fluorescent probes that can be seen and quantified by a portable machine. Software analysis of the fluorescing DNA allows clinicians to determine with great accuracy whether the virus is present in a patient's blood and/or how much is there.

The researchers calibrated the test by also amplifying an internal positive control not found in human blood. "It's amplified by the same primers as the HIV sequence, so it tells us that the assay is working properly," Rohrman said.

The students originally intended their work to look for HIV in infants, but the technique can also help to track viral loads in older patients. "It's important for clinicians to be able to quantitatively monitor patients' viral loads in order to ensure the disease is responding to therapy," Crannell said.

To be clinically viable, a DNA-based test for HIV has to be able to quantify virus loads over four orders of magnitude, from very low to very high, the researchers said. They reported the Rice test easily meets that goal.

They are developing tools for low-resource settings where high-tech lab equipment is not available. Although they used a thermal cycler, the researchers are working on a technique that will keep the entire procedure between room and body temperatures so that it can be performed at the point of care in the developing world.

Mechanism that forms cell-to-cell catch bonds found by researchers

 

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This ribbon diagram shows a pulling force applied to two common adhesion proteins called cadherins (red and blue) bound together in an X-shape. The green spheres represent calcium ions while the cyan and orange stick figures correspond to amino acids brought together as the force is applied. The hydrogen bonds that form between the amino acids create catch bonds that get stronger when pulled.

Certain bonds connecting biological cells get stronger when they're tugged. Those bonds could help keep hearts together and pumping; breakdowns of those bonds could help cancer cells break away and spread.

Those bonds are known as catch bonds and they're formed by common adhesion proteins called cadherins. Sanjeevi Sivasankar, an Iowa State University assistant professor of physics and astronomy and an associate of the U.S. Department of Energy's Ames Laboratory, has described catch bonds as "nanoscale seatbelts. They become stronger when pulled."

But how does that happen? How can bonds get stronger under force?

Sivasankar and his research team have found long-lived, force-induced hydrogen bonds are the answer. A paper describing their findings, "Resolving the molecular mechanism of cadherin catch bond formation," has just been published online by Nature Communications.

Sivasankar is the corresponding author. Co-authors are Kristine Manibog, an Iowa State graduate student in physics and astronomy and a student associate of the Ames Laboratory; Hui Li, of the Suzhou Institute of Biomedical Engineering and Technology of the Chinese Academy of Sciences in Suzhou New District, China; and Sabyasachi Rakshit, of the Indian Institute of Science Education and Research in Mohali, India. Li and Rakshit are former postdoctoral researchers in Sivasankar's laboratory.

The team's research was supported by grants from the American Cancer Society and the American Heart Association.

Sivasankar said strong cell-to-cell bonds are important to heart health and fighting cancer. He said the bonds connecting heart cells have to withstand constant mechanical forces. And, in some cancers, he said bonds no longer resist forces, allowing cancer cells to detach and spread.

To find the mechanism behind the strong ties created by catch bonds, Sivasankar's research team began with molecular dynamics and steered molecular dynamics computer simulations based on data from previous experiments. They found that two rod-shaped cadherins bound together in an X-shape (called an X-dimer) form catch bonds when pulled and in the presence of calcium ions.

The calcium ions keep the cadherins rigid and ordered while the pulling brings parts of the proteins closer together. All of that allows a series of hydrogen bonds to form. These long-lived, force-induced hydrogen bonds lock the X-dimers into tighter contact.

Sivasankar said the researchers followed up the simulations with single-molecule experiments using atomic force microscopy. The experiments confirmed that cadherin X-dimers, when pulled and exposed to high calcium ion concentrations, formed catch bonds. Take away the force or the calcium ions, and catch bond formation was eliminated.

All of this, Sivasankar said, helps explain the biophysics of cell-to-cell adhesion. And that's important to all of us.

"Robust cadherin adhesion," the researchers wrote in their paper, "is essential for maintaining the integrity of tissue such as the skin, blood vessels, cartilage and muscle that are exposed to continuous mechanical assault."

O mau gerenciamento das grandes empresas e a inflação decorrente.

 

Acontece um “fenômeno” muito simples de entender quando a situação econômica de um país,  (e quero me referir ao meu país, Brasil, mas aplica-se também a outros países) começa a aumentar devido à famigerada inflação que quando descontrolada, irá gerar recessão, desemprego e mais inflação ainda.

Isso acontece porque isso é baseado em que nós todos somos diferentes em nossos raciocínios, modos de encarar um problema, e vários outros fatores, ou seja “cada cabeça,uma sentença”.

Mas esse “nós todos, acima” em questões econômicas em um país, está restrita aos grandes empresários, os fabricantes de produtos essenciais de grande ou pequeno porte, em suma, qualquer grande empresa. Os demais do “nós todos” são os consumidores, que nada tem a ver com o aumento da inflação de maneira direta, eles são os que sofrem com ela. E irá também  refletir nas grandes empresas, porém estas tem reservas para suportar por algum tempo um período recessivo. Quem sofre mesmo é o consumidor.

E por que isso acontece? Supondo-se que um fornecedor ou fornecedores de matéria-prima para uma grande empresa tenha um gerenciamento falho ou confuso e até mesmo incompetente, seguramente irá repassar um preço maior da matéria-prima às indústrias que fazem parte de sua rede. E as grandes empresas, que via de regra também contam com administradores com algum tipo de problema de gerenciamento, imediatamente, sem pensar em alguma solução, irão repassar o aumento da matéria-prima no produto final.

E pensar que a solução, tanto para os fornecedores de matéria-prima quanto para os fabricantes é básicamente simples para manter os preços sem gerar inflação.

Muita coisa pode ser alterada numa grande empresa num momento de crise econômica visando manter os preços controlados, e isso irá beneficiar A TODOS.

Exemplos : gerenciamento da energia consumida em iluminação e força motriz, cortes de gastos supérfluos, (e tem muitos), uso de veículos simples para o transporte pessoal da diretoria, redução nos salários da “alta cúpula” da empresa. Ninguém pensa nisso nessa hora, sem raciocinar que com tudo voltando ao normal, os salários também voltarão, os “carrões voltarão”. Dá para elaborar uma lista extensa do que pode ser “economizada” nas grandes empresas.

E quanto ao governo? O governo federal também com todos os seus departamentos, e os governos estaduais e municipais funciona exatamente como uma grande empresa no que se refere ao corte de gastos supérfluos e tudo o mais.

Resumindo, inflação só existe quando não há um bom gerenciamento do governo e das empresas.

 

JSMelo

 

 

Chemical element bromine is essential to life in humans and other animals, researchers discover

 

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Twenty-seven chemical elements are considered to be essential for human life. Now there is a 28th — bromine.

Twenty-seven chemical elements are considered to be essential for human life. Now there is a 28th: bromine.

In a paper published by the journal Cell, Vanderbilt University researchers establish for the first time that bromine, among the 92 naturally-occurring chemical elements in the universe, is the 28th element essential for tissue development in all animals, from primitive sea creatures to humans.

"Without bromine, there are no animals. That's the discovery," said Billy Hudson, Ph.D., the paper's senior author and Elliott V. Newman Professor of Medicine.

The researchers, led by co-first authors Scott McCall, Christopher Cummings, Ph.D., and Gautam (Jay) Bhave, M.D., Ph.D., showed that fruit flies died when bromine was removed from their diet but survived when bromine was restored.

This finding has important implications for human disease. "Multiple patient groups … have been shown to be bromine deficient," said McCall, an M.D./Ph.D. student. Bromine supplementation may improve the health of patients on dialysis or total parenteral nutrition (TPN), for example.

The report is the latest in a series of landmark papers by the Vanderbilt group that have helped define how collagen IV scaffolds undergird the basement membrane of all tissues, including the kidney's filtering units.

Hudson said the foundation for the discovery about bromine goes back 30 years when he was at the University of Kansas Medical School.

Curiosity about two rare kidney diseases led, in the mid-1980s, to the discovery of two previously unknown proteins that twist around each other to form the triple-helical collagen IV molecule, like cables supporting a bridge. Disease results when these cables are defective or damaged.

Hudson moved to Vanderbilt in 2002.

In 2009, colleagues led by Roberto Vanacore, Ph.D., assistant professor of Medicine, reported in Science magazine the discovery of a novel sulfilimine bond between a sulfur atom and a nitrogen atom that acts like a "fastener" to connect the collagen IV molecules forming scaffolds for cells.

A defective bond may trigger the rare auto-immune disease Goodpasture's syndrome. The disorder is named for the late Vanderbilt pathologist and former medical school dean Ernest Goodpasture, M.D., who was best known for his contribution to the development of vaccines. That discovery led to simple question: how is the bond formed?

In 2012, Bhave, assistant professor of Medicine, Cummings, now a postdoctoral fellow, and Vanacore led the effort that found the answer -- the enzyme peroxidasin.

Conserved across the animal kingdom, peroxidasin also may play a role in disease. An overactive enzyme may lead to excessive deposition of collagen IV and thickening of the basement membrane, which can impair kidney function, they reported in the journal Nature Chemical Biology.

In the current study, to which Vanacore and Andrea Page-McCaw, Ph.D., associate professor of Cell and Developmental Biology, also contributed, the scientists demonstrated the unique and essential role for ionic bromide as a "co-factor," enabling peroxidasin to form the sulfilimine bond.

The chemical element bromine is thus "essential for animal development and tissue architecture," they report.

Making artificial vision look more natural

 

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Chichilnisky and colleagues used an electrode array to record activity from retinal ganglion cells (yellow and blue) and feed it back to them, reproducing the cells' responses to visual stimulation.

In laboratory tests, researchers have used electrical stimulation of retinal cells to produce the same patterns of activity that occur when the retina sees a moving object. Although more work remains, this is a step toward restoring natural, high-fidelity vision to blind people, the researchers say. The work was funded in part by the National Institutes of Health.

Just 20 years ago, bionic vision was more a science fiction cliché than a realistic medical goal. But in the past few years, the first artificial vision technology has come on the market in the United States and Western Europe, allowing people who've been blinded by retinitis pigmentosa to regain some of their sight. While remarkable, the technology has its limits. It has enabled people to navigate through a door and even read headline-sized letters, but not to drive, jog down the street, or see a loved one's face.

A team based at Stanford University in California is working to improve the technology by targeting specific cells in the retina -- the neural tissue at the back of the eye that converts light into electrical activity.

"We've found that we can reproduce natural patterns of activity in the retina with exquisite precision," said E.J. Chichilnisky, Ph.D., a professor of neurosurgery at Stanford's School of Medicine and Hansen Experimental Physics Laboratory. The study was published in Neuron, and was funded in part by NIH's National Eye Institute (NEI) and National Institute of Biomedical Imaging and Bioengineering (NIBIB).

The retina contains several cell layers. The first layer contains photoreceptor cells, which detect light and convert it into electrical signals. Retinitis pigmentosa and several other blinding diseases are caused by a loss of these cells. The strategy behind many bionic retinas, or retinal prosthetics, is to bypass the need for photoreceptors and stimulate the retinal ganglion cell layer, the last stop in the retina before visual signals are sent to the brain.

Several types of retinal prostheses are under development. The Argus II, which was developed by Second Sight Therapeutics with more than $25 million in support from NEI, is the best known of these devices. In the United States, it was approved for treating retinitis pigmentosa in 2013, and it's now available at a limited number of medical centers throughout the country. It consists of a camera, mounted on a pair of goggles, which transmits wireless signals to a grid of electrodes implanted on the retina. The electrodes stimulate retinal ganglion cells and give the person a rough sense of what the camera sees, including changes in light and contrast, edges, and rough shapes.

"It's very exciting for someone who may not have seen anything for 20-30 years. It's a big deal. On the other hand, it's a long way from natural vision," said Dr. Chichilnisky, who was not involved in development of the Argus II.

Current technology does not have enough specificity or precision to reproduce natural vision, he said. Although much of visual processing occurs within the brain, some processing is accomplished by retinal ganglion cells. There are 1 to 1.5 million retinal ganglion cells inside the retina, in at least 20 varieties. Natural vision -including the ability to see details in shape, color, depth and motion -- requires activating the right cells at the right time.

The new study shows that patterned electrical stimulation can do just that in isolated retinal tissue. The lead author was Lauren Jepson, Ph.D., who was a postdoctoral fellow in Dr. Chichilnisky's former lab at the Salk Institute in La Jolla, California. The pair collaborated with researchers at the University of California, San Diego, the Santa Cruz Institute for Particle Physics, and the AGH University of Science and Technology in Krakow, Poland.

They focused their efforts on a type of retinal ganglion cell called parasol cells. These cells are known to be important for detecting movement, and its direction and speed, within a visual scene. When a moving object passes through visual space, the cells are activated in waves across the retina.

The researchers placed patches of retina on a 61-electrode grid. Then they sent out pulses at each of the electrodes and listened for cells to respond, almost like sonar. This enabled them to identify parasol cells, which have distinct responses from other retinal ganglion cells. It also established the amount of stimulation required to activate each of the cells. Next, the researchers recorded the cells' responses to a simple moving image -- a white bar passing over a gray background. Finally, they electrically stimulated the cells in this same pattern, at the required strengths. They were able to reproduce the same waves of parasol cell activity that they observed with the moving image.

"There is a long way to go between these results and making a device that produces meaningful, patterned activity over a large region of the retina in a human patient," Dr. Chichilnisky said. "But if we can handle the many technical hurdles ahead, we may be able to speak to the nervous system in its own language, and precisely reproduce its normal function."

Such advances could help make artificial vision more natural, and could be applied to other types of prosthetic devices, too, such as those being studied to help paralyzed individuals regain movement. NEI supports many other projects geared toward retinal prosthetics.

"Retinal prosthetics hold great promise, but this research is a marathon, not a sprint," said Thomas Greenwell, Ph.D., a program director in retinal neuroscience at NEI. "This important study helps illustrate the challenges of restoring high-quality vision, one group's progress toward that goal, and the continued need to for the entire field to keep innovating."

The study was funded by NIH grants EY012171 and EB004410, the National Science Foundation, the McKnight Foundation, the San Diego Foundation Blasker Award, and the Polish government.

Flowers' polarization patterns help bees find food

 

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Bees use their ability to 'see' polarized light when foraging for food.

Bees use their ability to 'see' polarized light when foraging for food, researchers based at the University of Bristol have discovered. This is the first time bees have been found to use this ability for something other than navigation.

Like many other insect pollinators, bees find their way around by using a polarization sensitive area in their eyes to 'see' skylight polarization patterns. However, while other insects are known to use such sensitivity to identify appropriate habitats, locate suitable sites to lay their eggs and find food, a non-navigation function for polarization vision has never been identified in bees -- until now.

Professor Julian Partridge, from Bristol's School of Biological Sciences and the School of Animal Biology at the University of Western Australia, with his Bristol-based colleagues investigated whether bumblebees (Bombus terrestris) can learn the polarization patterns of artificial 'flowers' in order to obtain a food reward.

They found that freely foraging bumblebees soon learnt to differentiate between rewarding (sucrose solution providing) and aversive (quinine solution providing) artificial 'flowers' with two different polarization patterns. However, the bees could only discriminate between the two targets when the targets were viewed from below.

Polarization patterns occur on the petals of real flowers but are invisible to us and thus may be a hitherto overlooked component of floral signalling. Around 53 per cent of flower species face downwards and thus their polarization patterns are presented in such a way as to be visually accessible to the region of the bee's eye which includes the polarization sensitive Dorsal Rim Area. Light reflected from downward facing flowers also has the potential to contrast with skylight polarization patterns, potentially helping the bee to detect and identify such flowers.

Professor Partridge said: "Both pollinator and plant fitness is greatly dependent on the ability of pollinators to discriminate flowers accurately, and bees have been shown to be able to use a wide range of floral cues, including colour, shape, texture, certain chemical compounds and temperature, to improve the identification and recognition of flowers.

"Recent findings have added floral humidity and electric fields as additional methods with which pollinators can discriminate flowers, and it is advantageous for a plant to produce a number of different signals that a pollinator can utilise effectively. Our findings suggest polarisation vision may provide sensory access to an additional floral cue for bees."

Sleep after learning strengthens connections between brain cells and enhances memory

 

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A new study provides important physical evidence that sleep helps consolidate and strengthen new memories.

In study published today in Science, researchers at NYU Langone Medical Center show for the first time that sleep after learning encourages the growth of dendritic spines, the tiny protrusions from brain cells that connect to other brain cells and facilitate the passage of information across synapses, the junctions at which brain cells meet. Moreover, the activity of brain cells during deep sleep, or slow-wave sleep, after learning is critical for such growth.

The findings, in mice, provide important physical evidence in support of the hypothesis that sleep helps consolidate and strengthen new memories, and show for the first time how learning and sleep cause physical changes in the motor cortex, a brain region responsible for voluntary movements.

"We've known for a long time that sleep plays an important role in learning and memory. If you don't sleep well you won't learn well," says senior investigator Wen-Biao Gan, PhD, professor of neuroscience and physiology and a member of the Skirball Institute of Biomolecular Medicine at NYU Langone Medical Center. "But what's the underlying physical mechanism responsible for this phenomenon? Here we've shown how sleep helps neurons form very specific connections on dendritic branches that may facilitate long-term memory. We also show how different types of learning form synapses on different branches of the same neurons, suggesting that learning causes very specific structural changes in the brain."

On the cellular level, sleep is anything but restful: Brain cells that spark as we digest new information during waking hours replay during deep sleep, also known as slow-wave sleep, when brain waves slow down and rapid-eye movement, as well as dreaming, stops. Scientists have long believed that this nocturnal replay helps us form and recall new memories, yet the structural changes underpinning this process have remained poorly understood.

To shed light on this process, Dr. Gan and colleagues employed mice genetically engineered to express a fluorescent protein in neurons. Using a special laser-scanning microscope that illuminates the glowing fluorescent proteins in the motor cortex, the scientists were then able to track and image the growth of dendritic spines along individual branches of dendrites before and after mice learned to balance on a spin rod. Over time mice learned how to balance on the rod as it gradually spun faster. "It's like learning to ride a bike," says Dr. Gan. "Once you learn it, you never forget."

After documenting that mice, in fact, sprout new spines along dendritic branches, within six hours after training on the spinning rod, the researchers set out to understand how sleep would impact this physical growth. They trained two sets of mice: one trained on the spinning rod for an hour and then slept for 7 hours; the second trained for the same period of time on the rod but stayed awake for 7 hours. The scientists found that the sleep-deprived mice experienced significantly less dendritic spine growth than the well-rested mice. Furthermore, they found that the type of task learned determined which dendritic branches spines would grow.

Running forward on the spinning rod, for instance, produced spine growth on different dendritic branches than running backward on the rod, suggesting that learning specific tasks causes specific structural changes in the brain.

"Now we know that when we learn something new, a neuron will grow new connections on a specific branch," says Dr. Gan. "Imagine a tree that grows leaves (spines) on one branch but not another branch. When we learn something new, it's like we're sprouting leaves on a specific branch."

Finally, the scientists showed that brain cells in the motor cortex that activate when mice learn a task reactivate during slow-wave deep sleep. Disrupting this process, they found, prevents dendritic spine growth. Their findings offer an important insight into the functional role of neuronal replay -- the process by which the sleeping brain rehearses tasks learned during the day -- observed in the motor cortex.

"Our data suggest that neuronal reactivation during sleep is quite important for growing specific connections within the motor cortex," Dr. Gan adds.

Gene study shows how sheep first separated from goats

 

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Scientists at the University of Edinburgh's Roslin Institute have helped to crack the genetic code of sheep. The team were part of the International Sheep Genomics Consortium which sequenced the entire genetic make-up of a texel sheep, the same breed shown in this image. Their findings reveal that sheep became a distinct species from goats around 4 million years ago.

Scientists have cracked the genetic code of sheep to reveal how they became a distinct species from goats around four million years ago.

The study is the first to pinpoint the genetic differences that make sheep different from other animals.

The findings could aid the development of DNA testing to speed-up selective breeding programmes, helping farmers to improve their stocks.

The research identifies the genes that give sheep their fleece and uncovers features of their digestive system, which makes them so well-suited to a diet of low quality grass and other plants.

It also builds the most complete picture yet of sheep's complex biology. Further studies using this resource could reveal new insights to diseases that affect sheep.

Researchers from the University of Edinburgh's Roslin Institute, which receives strategic funding from the Biotechnology and Biological Sciences Research Council, were part of a global team that has decoded the genome sequence -- the entire genetic make-up -- of domestic sheep for the first time.

This team -- the International Sheep Genomics Consortium -- compared the sheep's genes with those of other animals -- including humans, cattle, goats and pigs.

The analysis identifies several genes that are associated with wool production. It also reveals genes that underpin the evolution of the rumen -- a specialised chamber of the stomach that breaks down plant material to make it ready for digestion.

This collaborative study, involving 26 research institutions in eight different countries, was led by researchers from the Commonwealth Scientific and Industrial Research Organisation, Australia; BGI and the Kunming Institute of Zoology, China; Utah State University and Baylor College of Medicine in the US; and The Roslin Institute.

The BBSRC-funded ARK-Genomics facility -- which is part of Edinburgh Genomics at the University of Edinburgh -- provided a substantial body of sequence data, including information on which genes are expressed in a spectrum of 40 different tissues.

The study is published today in the journal Science.

Professor Alan Archibald, Head of Genetics and Genomics at The Roslin Institute, said: "Sheep were one of the first animals to be domesticated for farming and are still an important part of the global agricultural economy. Understanding more about their genetic make-up will help us to breed healthier and more productive flocks."

Stem cells hold keys to body's plan

 

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Four-cell embryo (stock illustration). Researchers have discovered landmarks within pluripotent stem cells that guide how they develop to serve different purposes within the body. This breakthrough offers promise that scientists eventually will be able to direct stem cells in ways that prevent disease or repair damage from injury or illness. Pluripotent stem cells are so named because they can evolve into any of the cell types that exist within the body.

Case Western Reserve researchers have discovered landmarks within pluripotent stem cells that guide how they develop to serve different purposes within the body. This breakthrough offers promise that scientists eventually will be able to direct stem cells in ways that prevent disease or repair damage from injury or illness. The study and its results appear in the June 5 edition of the journal Cell Stem Cell.

Pluripotent stem cells are so named because they can evolve into any of the cell types that exist within the body. Their immense potential captured the attention of two accomplished faculty with complementary areas of expertise.

"We had a unique opportunity to bring together two interdisciplinary groups," said co-senior author Paul Tesar, PhD, Assistant Professor of Genetics and Genome Sciences at CWRU School of Medicine and the Dr. Donald and Ruth Weber Goodman Professor.

"We have exploited the Tesar lab's expertise in stem cell biology and my lab's expertise in genomics to uncover a new class of genetic switches, which we call seed enhancers," said co-senior author Peter Scacheri, PhD, Associate Professor of Genetics and Genome Sciences at CWRU School of Medicine. "Seed enhancers give us new clues to how cells morph from one cell type to another during development."

The breakthrough came from studying two closely related stem cell types that represent the earliest phases of development -- embryonic stem cells and epiblast stem cells, first described in research by Tesar in 2007. "These two stem cell types give us unprecedented access to the earliest stages of mammalian development," said Daniel Factor, graduate student in the Tesar lab and co-first author of the study.

Olivia Corradin, graduate student in the Scacheri lab and co-first author, agrees. "Stem cells are touted for their promise to make replacement tissues for regenerative medicine," she said. "But first, we have to understand precisely how these cells function to create diverse tissues."

Enhancers are sections of DNA that control the expression of nearby genes. By comparing these two closely related types of pluripotent stem cells (embryonic and epiblast), Corradin and Factor identified a new class of enhancers, which they refer to as seed enhancers. Unlike most enhancers, which are only active in specific times or places in the body, seed enhancers play roles from before birth to adulthood.

They are present, but dormant, in the early mouse embryonic stem cell population. In the more developed mouse epiblast stem cell population, they become the primary enhancers of their associated genes. As the cells mature into functional adult tissues, the seed enhancers grow into super enhancers. Super enhancers are large regions that contain many enhancers and control the most important genes in each cell type.

"These seed enhancers have wide-ranging potential to impact the understanding of development and disease," said Stanton Gerson, MD, Asa & Patricia Shiverick and Jane Shiverick (Tripp) Professor of Hematological Oncology and Director of the National Center for Regenerative Medicine at Case Western Reserve University. "In the stem cell field, this understanding should rapidly enhance the ability to generate clinically useful cell types for stem cell-based regenerative medicine."

"Our next step is to understand if mis-regulation of these seed enhancers might play a role in human diseases," Tesar said. "The genes controlled by seed enhancers are powerful ones, and it's possible that aberrations could contribute to things like heart disease or neurodegenerative disorders."

Scacheri added, "It is also clear that cancer can be driven by changes in enhancers, and we are interested in understanding the role of seed enhancers in cancer onset and progression."