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Researchers at University of Texas at Dallas (UT Dallas) have created a material made from nanofibers that can stretch to up to seven times its length while remaining tougher than Kevlar. These structures absorb up to 98 joules per gram. Kevlar, often used to make bulletproof vests, can absorb up to 80 joules per gram. The researchers hope the structures will one day form material that can reinforce itself at points of high stress and could potentially be used in military airplanes or other defense applications.
In a study published by ACS Applied Materials and Interfaces, a journal of the American Chemical Society, researchers twisted nanofiber into yarns and coils. The electricity generated by stretching the twisted nanofiber formed an attraction ten times stronger than a hydrogen bond, which is considered one of the strongest forces formed between molecules.
Researchers sought to mimic their earlier work on the piezoelectric action (how pressure forms electric charges) of collagen fibers found inside bone in hopes of creating high-performance materials that can reinforce itself, said Dr. Majid Minary, an assistant professor of mechanical engineering in the University’s Erik Jonsson School of Engineering and Computer Science and senior author of the study.
“We reproduced this process in nanofibers by manipulating the creation of electric charges to result in a lightweight, flexible, yet strong material,” said Minary, who is also a member of the Alan G. MacDiarmid NanoTech Institute. “Our country needs such materials on a large scale for industrial and defense applications.”
Luke Skywalker’s home in “Star Wars” is the desert planet Tatooine, with twin sunsets because it orbits two stars. So far, only uninhabitable gas-giant planets have been identified circling such binary stars, and many researchers believe rocky planets cannot form there. Now, mathematical simulations show that Earthlike, solid planets such as Tatooine likely exist and may be widespread.
“Tatooine sunsets may be common after all,” concludes the study by astrophysicists Ben Bromley of the University of Utah and Scott Kenyon of the Smithsonian Astrophysical Observatory.
“Our main result is that outside a small region near a binary star, [either rocky or gas-giant] planet formation can proceed in much the same way as around a single star,” they write. “In our scenario, planets are as prevalent around binaries as around single stars.”
The study has been submitted to Astrophysical Journal for review, but as is the custom in the field, the authors have posted the unreviewed paper on the scientific preprint website ArXiv.
The title of the new study is “Planet formation around binary stars: Tatooine made easy,” but the paper looks anything but easy: it is filled with mathematical formulas describing how binary stars can be orbited by planetesimals – asteroid-sized rocks that clump together to form planets.
“We took our sweet numerical time to show that the ride around a pair of stars can be just as smooth as around one,” when it comes to the early steps of planet formation, Bromley says. “The ‘made easy’ part is really saying the same recipe that works around the sun will work around Tatooine’s host stars.”
“For over a decade, astrophysicists believed that planets like Earth could not form around most binary stars, at least not close enough to support life,” he says. “The problem is that planetesimals need to merge gently together to grow. Around a single star, planetesimals tend to follow circular paths – concentric rings that do not cross. If planetesimals do approach each other, they can merge together gently.”
But if planetesimals orbit a pair of stars, “their paths get mixed up by the to-and-fro pull of the binary stars,” Bromley says. “Their orbits can get so tangled that they cross each other’s paths at high speeds, dooming them to destructive collisions, not growth.”
Previous research started with circular orbits when pondering planet formation around binary stars, Bromley says, while the new study shows that “planets, when they are small, will naturally seek these oval orbits and never start off on circular ones. … If the planetesimals are in an oval-shaped orbit instead of a circle, their orbits can be nested and they won’t bash into each other. They can find orbits where planets can form.”
A frog in Ecuador's western Andean cloud forest changes skin texture in minutes, appearing to mimic the texture it sits on. Originally discovered by a Case Western Reserve University PhD student and her husband, a projects manager at Cleveland Metroparks' Natural Resources Division, the amphibian is believed to be the first known to have this shape-shifting capability.
The new frog is now officially called Pristimantis mutabilis, or mutable rainfrog. Colleagues working with the couple recently found that a known relative of the frog shares the same texture-changing quality--but it was never reported before.
The frogs are found at Reserva Las Gralarias, a nature reserve originally created to protect endangered birds in the Parish of Mindo, in north-central Ecuador.
The researchers, Katherine and Tim Krynak, and colleagues from Universidad Indoamérica and Tropical Herping (Ecuador) co-authored a manuscript describing the new animal and skin texture plasticity in the Zoological Journal of the Linnean Society. They believe their findings have broad implications for how species are and have been identified. The process may now require photographs and longer observations in the field to ensure the one species is not mistakenly perceived as two because at least two species of rain frogs can change their appearance.
Katherine Krynak believes the ability to change skin texture to reflect its surroundings may enable P. mutabilis to help camouflage itself from birds and other predators. The Krynaks originally spotted the small, spiny frog, nearly the width of a marble, sitting on a moss-covered leaf about a yard off the ground on a misty July night in 2009. The Krynaks had never seen this animal before, though Tim had surveyed animals on annual trips to Las Gralarias since 2001, and Katherine since 2005.
They captured the little frog and tucked it into a cup with a lid before resuming their nightly search for wildlife. They nicknamed it "punk rocker" because of the thorn-like spines covering its body. The next day, Katherine Krynak pulled the frog from the cup and set it on a smooth white sheet of plastic for Tim to photograph. It wasn't "punk "--it was smooth-skinned. They assumed that, much to her dismay, she must have picked up the wrong frog. "I then put the frog back in the cup and added some moss," she said. "The spines came back... we simply couldn't believe our eyes, our frog changed skin texture!
Researchers studying cancer and other invasive diseases rely on high-resolution imaging to see tumors and other activity deep within the body's tissues. Using a new high-speed, high-resolution imaging method, Lihong Wang, PhD, and his team at Washington University in St. Louis were able to see blood flow, blood oxygenation, oxygen metabolism and other functions inside a living mouse brain at faster rates than ever before.
Using photoacoustic microscopy (PAM), a single-wavelength, pulse-width-based technique developed in his lab, Wang, the Gene K. Beare Professor of Biomedical Engineering in the School of Engineering & Applied Science, was able to take images of blood oxygenation 50 times faster than their previous results using fast-scanning PAM; 100 times faster than their acoustic-resolution system; and more than 500 times faster than phosphorescence-lifetime-based two-photon microscopy (TPM).
Other existing methods, including functional MRI (fMRI), TPM and wide-field optical microscopy, have provided information about the structure, blood oxygenation and flow dynamics of the mouse brain. However, those methods have speed and resolution limits, Wang says.
To make up for these limitations, Wang and his lab implemented fast-functional PAM, which allowed them to get high-resolution, high-speed images of a living mouse brain through an intact skull. This method achieved a lateral spatial resolution of five times finer than the lab's previous fast-scanning system; 25 times finer than its previous acoustic-resolution system; and more than 35 times finer than ultrasound-array-based photoacoustic computed tomography.
Most importantly, PAM allowed 3-D blood oxygenation imaging with capillary-level resolution at a one-dimensional imaging rate of 100 kHz, or 10 microseconds.
Astronomers have discovered thousands of exoplanets in our galaxy, the Milky Way, using the Kepler satellite and many of them have multiple planets orbiting the host star. By analyzing these planetary systems, researchers from the Australian National University and the Niels Bohr Institute in Copenhagen have calculated the probability for the number of stars in the Milky Way that might have planets in the habitable zone. The calculations show that billions of the stars in the Milky Way will have one to three planets in the habitable zone, where there is the potential for liquid water and where life could exist. The results are published in the scientific journal, Monthly Notices of the Royal Astronomical Society.
Using NASA’s Kepler satellite, astronomers have found about 1,000 planets around stars in the Milky Way and they have also found about 3,000 other potential planets. Many of the stars have planetary systems with 2-6 planets, but the stars could very well have more planets than those observable with the Kepler satellite, which is best suited for finding large planets that orbit relatively close to their stars.
Planets that orbit close to their stars would be too scorching hot to have life, so to find out if such planetary systems might also have planets in the habitable zone with the potential for liquid water and life, a group of researchers from the Australian National University and the Niels Bohr Institute at the University of Copenhagen made calculations based on a new version of a 250-year-old method called the Titius-Bode law.
The law states that there is a certain ratio between the orbital periods of planets in a solar system. So the ratio between the orbital period of the first and second planet is the same as the ratio between the second and the third planet and so on. Therefore, if you knew how long it takes for some of the planets to orbit around the Sun/star, you can calculate how long it takes for the other planets to orbit and can thus calculate their position in the planetary system. You can also calculate if a planet is ‘missing’ in the sequence.
“We decided to use this method to calculate the potential planetary positions in 151 planetary systems, where the Kepler satellite had found between 3 and 6 planets. In 124 of the planetary systems, the Titius-Bode law fit with the position of the planets as good as or better than our own solar system. Using T-B’s law we tried to predict where there could be more planets further out in the planetary systems. But we only made calculations for planets where there is a good chance that you can see them with the Kepler satellite,” explains Steffen Kjær Jacobsen, PhD student in the research group Astrophysics and Planetary Science at the Niels Bohr Institute at the University of Copenhagen.
The researchers evaluated the number of planets in the habitable zone based on the extra planets that were added to the 151 planetary systems according to the Titius-Bode law. The result was 1-3 planets in the habitable zone for each planetary system. If you then take the calculations further out into space, it would mean that just in our galaxy, the Milky Way, there could be billions of stars with planets in the habitable zone, where there could be liquid water and where life could exist.
Distasteful as it sounds, the transplantation of fecal matter is more successful for treating Clostridium difficile infections than previously thought. The research, published in the open access journal Microbiome, reveals that healthy changes to a patient's microbiome are sustained for up to 21 weeks after transplant, and has implications for the regulation of the treatment.
Clostridium difficile infections are a growing problem, leading to recurrent cases of diarrhea and severe abdominal pain, with thousands of fatalities worldwide every year. The infection is thought to work by overrunning the intestinal microbiome - the ecosystem of microorganisms that maintain a healthy intestine.
Fecal microbiota transplantation was developed as a method of treating C. difficile infection, and is particularly successful in patients who suffer repeat infections. Fecal matter is collected from a donor, purified, mixed with a saline solution and placed in a patient, usually by colonoscopy.
Previous research has shown that the fecal microbiota of patients resembles that of the donor, but not much is known about the short and long term stability of fecal microbiota transplanted into recipients.
In this research, Michael Sadowsky and colleagues at the University of Minnesota collected fecal samples from four patients before and after their fecal transplants. Three patients received freshly prepared microbiota from fecal matter and one patient received fecal microbiota that had previously been frozen. All received fecal microbiota from the same pre-qualified donor.
The team compared the pre- and post-transplant fecal microbial communities from the four patients, as well as from 10 additional patients with recurring C. difficile infections, to the sequences of normal subjects described in the Human Microbiome Project. In addition, they looked at the changes in fecal bacterial composition in recipients over time, and compared this to the changes observed within samples from the donor.
Surprisingly, after transplantation, patient samples appeared to sustain changes in their microbiome for up to 21 weeks and remained within the spectrum of fecal microbiota characterized as healthy.
SNARE proteins are known as the minimal machinery for membrane fusion. To induce membrane fusion, the proteins combine to form a SNARE complex in a four helical bundle, and NSF and α-SNAP disassemble the SNARE complex for reuse. In particular, NSF can bind an energy source molecule, adenosine triphosphate (ATP), and the ATP-bound NSF develops internal tension via cleavage of ATP. This process is used to exert great force on SNARE complexes, eventually pulling them apart. However, although about 30 years have passed since the Nobel Prize winners' discovery, how NSF/α-SNAP disassembled the SNARE complex remained a mystery to scientists due to a lack in methodology.
In a recent issue of Science, published on March 27, 2015, a research team, led by Tae-Young Yoon of the Department of Physics at the Korea Advanced Institute of Science and Technology (KAIST) and Reinhard Jahn of the Department of Neurobiology of the Max-Planck-Institute for Biophysical Chemistry, reports that NSF/α-SNAP disassemble a single SNARE complex using various single-molecule biophysical methods that allow them to monitor and manipulate individual protein complexes. "We have learned that NSF releases energy in a burst within 20 milliseconds to "tear" the SNARE complex apart in a one-step global unfolding reaction, which is immediately followed by the release of SNARE proteins," said Yoon.
Previously, it was believed that NSF disassembled a SNARE complex by unwinding it in a processive manner. Also, largely unexplained was how many cycles of ATP hydrolysis were required and how these cycles were connected to the disassembly of the SNARE complex.
Yoon added, "From our research, we found that NSF requires hydrolysis of ATPs that were already bound before it attached to the SNAREs--which means that only one round of an ATP turnover is sufficient for SNARE complex disassembly. Moreover, this is possible because NSF pulls a SNARE complex apart by building up the energy from individual ATPs and releasing it at once, yielding a "spring-loaded" mechanism."
NSF is a member of the ATPases associated with various cellular activities family (AAA+ ATPase), which is essential for many cellular functions such as DNA replication and protein degradation, membrane fusion, microtubule severing, peroxisome biogenesis, signal transduction, and the regulation of gene expression. This research has added valuable new insights and hints for studying AAA+ ATPase proteins, which are crucial for various living beings.
Reference: "Spring-loaded unraveling of a single SNARE complex by NSF in one round of ATP turnover." (DOI: 10.1126/science.aaa5267)
No level of security screening short of mind-reading could have prevented the crash of Germanwings flight 9525. But what can be done? The New York Times editorial calls for the American standard that requires two crew members be in the cockpit at all times to be adopted by “all airlines.” This suggestion is reasonable, but would not prevent a team of two pilots from accomplishing a similarly evil deed. The Times correctly asserts ”Air travel over all remains incredibly safe.”
The plane in question, the Airbus A320, has among the world’s best safety records and was the first commercial airliner to have an all-digital fly-by-wire control system. Much of the criticism over the years of these fly-by-wire systems has focused on the problem of pilots becoming too dependent on technology, but these systems could also be a means of preventing future tragedies. In fly-by-wire planes, a story on a previous Airbus crash in Popular Mechanics reports, “The vast majority of the time, the computer operates within what’s known as normal law, which means that the computer will not enact any control movements that would cause the plane to leave its flight envelope. The flight control computer under normal law will not allow an aircraft to stall, aviation experts say.” If autopilot is disconnected or reset, as the New York Times reports it was on the Germanwings plane, it can be switched to alternate law, “a regime with far fewer restrictions on what a pilot can do.”
AI pioneer Jeff Hawkins has addressed the recent upswell of fear about AI and “superintelligence” in a post on Re/code. “The Terminator Is Not Coming,” his title announces. “The Future Will Thank Us.” We are so concerned, it seems, about giving machines too much power that we appear to miss the fact that the largest existential threat to humans is other humans. Such seems to be the case with Germanwings 4U9525.
Hawkins is the inventor of the Palm Pilot (the first personal digital assistant or PDA) and the Palm Treo (one of the first smartphones). He is also the co-founder, with Donna Dubinsky, of the machine intelligence company Numenta. Grok, the company’s first commercial product, sifts through massive amounts of server activity data on Amazon Web Services (AWS) to identify anomalous patterns of events. This same approach could easily be used to monitor flight data from airplanes and alert ground control in real time of the precise nature of unexpected activity. Numenta open sources its software (Numenta.org) and is known to DARPA and other government research agencies, so multiple parties could already be at work on such a system.
Hawkins’ approach to machine intelligence, Hierarchical Temporal Memory (HTM), has some distinct advantages over the highly-publicized technique of deep learning (DL). Both use hierarchies of matrices to learn patterns from large data sets. HTM takes its inspiration from biology and uses the layering of neurons in the brain as a model for its architecture. DL is primarily mathematical and projects the abstraction of the brain’s hierarchy to deeper and deeper levels. HTM uses larger matrices and flatter hierarchies to store patterns than DL and the data in these matrices is characterized by sparse distributions. Most important, HTM processes time-based data whereas DL trains mostly on static data sets.
For the emerging Internet of Things (IoT), time-based and real-time data is incredibly important. Systems that can learn continuously from these data streams, like Numenta’s, will be particularly valuable for keeping track of all of those things—including errant airplanes. Could machine intelligence have prevented this tragedy? Hawkins thinks so but notes, “All the intelligence in the world in the cockpit won’t solve any problem if the pilot decides to turn it off.” There will need to be aviation systems “designed for potential override from ground.” What are we the most scared of, individual agency or systematic control? Based on the Germanwings evidence so far,lack of override control from the ground is the greater threat.
Imagine being able to download a full-length 8GB HD movie to your phone in six seconds (versus seven minutes over 4G or more than an hour on 3G) and video chats so immersive that it will feel like you can reach out and touch the other person right through the screen.
That’s the vision for the 5G concept — the next generation of wireless networks — presented at the Mobile World Congress show last week, according to re/code.
Here’s what it will offer:
“Ulrich Dropmann, head of industry environment networks at Nokia, gave a scenario where you might be cruising in your driverless car when, unbeknownst to you, a crash has just occurred up the road,” says re/code. “With 5G, sensors placed along the road would be able to instantly relay that information back to your car (this is where having low latency is important), so it could brake earlier and avoid another accident.”
So when might it be here? “The most optimistic targets would see the first commercial network up and running by 2020, but even that may be too optimistic. As with LTE, it will take years for the network to become widespread.”
Seth Robertson and Viet Tran, engineering students of George Mason University, have a new explanation of how to put out a fire and they build their very own practical peace of fire-fighting technology.
Their new fire-fighting solution works with sound waves by pushing low frequency sound waves “30 to 60 hertz range” to the flames you can separate the oxygen from the fuel. The fire has a triangle of needs: Heat, Fuel and Oxygen. And simply by taking any of these needs away, you can put out the fire. What wave sound does to this triangle is to bring air (Oxygen) back and forth which keeps the air away from fire but in molecule levels. The fire will act like a cat going after a laser pointer light and that is all it takes to cut off the oxygen from the fire.
But the inventors have even more dreams for their new flagship, Washington post reports: “Robertson and Tran envision their technology being used to put out fires in homes — and in the wild. If properly scaled, sound-wave extinguishers would eliminate the need to douse forests in chemicals or waste untold gallons of water”. But that’s still a long way away.
Employing an ingenious microfluidic design that combines chemical and mechanical properties, a team of Harvard scientists has demonstrated a new way of detecting and extracting biomolecules from fluid mixtures. The approach requires fewer steps, uses less energy, and achieves better performance than several techniques currently in use and could lead to better technologies for medical diagnostics and chemical purification.
The biomolecule sorting technique was developed in the laboratory of Joanna Aizenberg, Amy Smith Berylson Professor of Materials Science at Harvard School of Engineering and Applied Sciences (SEAS) and Professor in the Department of Chemistry and Chemical Biology. Aizenberg is also co-director of the Kavli Institute for Bionano Science and Technology and a core faculty member at Harvard’s Wyss Institute for Biologically Inspired Engineering, leading the Adaptive Materials Technologies platform there.
The new microfluidic device, described in a paper appearing today in the journal Nature Chemistry, is composed of microscopic “fins” embedded in a hydrogel that is able to respond to different stimuli, such as temperature, pH, and light. Special DNA strands called aptamers, that under the right conditions bind to a specific target molecule, are attached to the fins, which move the cargo between two chemically distinct environments. Modulating the pH levels of the solutions in those environments triggers the aptamers to “catch” or “release” the target biomolecule.
After using computer simulations to test their novel approach, in collaboration with Prof. Anna C. Balazs from the University of Pittsburgh, Aizenberg’s team conducted proof-of-concept experiments in which they successfully separated thrombin, an enzyme in blood plasma that causes the clotting of blood, from several mixtures of proteins. Their research suggests that the technique could be applicable to other biomolecules, or used to determine chemical purity and other characteristics in inorganic and synthetic chemistry.
“Our adaptive hybrid sorting system presents an efficient chemo-mechanical transductor, capable of highly selective separation of a target species from a complex mixture—all without destructive chemical modifications and high-energy inputs,” Aizenberg said. “This new approach holds promise for the next-generation, energy-efficient separation and purification technologies and medical diagnostics.”
With 3D printers everywhere, making everything from Yoda statues to bionic body parts, this company is using 3D printing to make new body tissue. BioBots, a team from the University of Pennsylvania, does just that. They’ve developed a $5,000 3D printer that actually prints functional living tissue. The company just snagged the Most Innovative Company at SXSW’s Accelerator Awards.
And while most of the living tissue BioBots is creating these days is for drug research — to make it less expensive and take animals out of the mix — one day, it could print new organs for transplants. “If we could somehow reveal the failures before testing drugs on people, we would be able to identify false positives much earlier in the drug development process,” CEO and co-founder Danny Cabrera told Forbes. “The problem is in animal testing – mice are not humans, and tests on animals often fail to mimic human diseases or predict how the human body responds to new drugs.
“The Holy Grail is to develop fully functioning replacement organs out of a patient’s own cells, eliminating the organ waiting list, but in the meantime we’ll settle for getting more drugs approved by the FDA at a significantly lower cost on an accelerated time scale, improving the quality of life for millions of people around the world.”
One of the dreams of both science fiction writers and practical robot builders has been realized, at least on a simple level: Cornell University researchers have created a machine that can build copies of itself.
Scientists have developed “nanoneedles” that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice.
The hope is that one day scientists will be able to help promote the generation of new blood vessels in people, using nanoneedles, to provide transplanted organs or future artificial organ implants with the necessary connections to the rest of the body, so that they can function properly with a minimal chance of being rejected.
“This is a quantum leap compared to existing technologies for the delivery of genetic material to cells and tissues,” said Ennio Tasciotti, Co-Chair, Department of Nanomedicine at Houston Methodist Research Institute and co-corresponding author of the paper.
In the complex, somewhat rarified world of interactions between various flavors of RNA, one elusive goal is to understand the precise regulatory relationships between competing endogenous RNA (ceRNA), microRNA (miRNA), small interfering RNA (siRNA) and messenger RNA (mRNA).
To enter this world prepared, here's a quick overview:
Recently, scientists at Tsinghua University, Beijing investigated competing endogenous RNAs cross-regulation by creating a computational model, using it to quantitatively describe a minimum ceRNA network, and experimentally validating their model's predictions by utilizing multifluorescent synthetic gene circuits in cultured human cells. They found that the ceRNA effect is affected by the abundance of miRNA and ceRNAs, the number and affinity of binding sites, and the mRNA degradation pathway determined by the degree of miRNA/mRNA complementarity (a mirror image-like property shared between two DNA or RNA sequences that allows DNA replication and transcription). The researchers state that their findings have the potential to increase understanding quantitative properties of gene regulatory systems, contribute to the development of better tools for cell-type specific microRNA occupancy rate prediction, and benefit synthetic biology or genetic engineering research using miRNA or ceRNA in building more predictive parts with better quantitative behaviors.
Discussing the paper that he, Prof. Zhen Xie and their colleagues published in Proceedings of the National Academy of Sciences, Prof. Xiaowo Wang tells Phys.org that one of the main challenges the researchers faced was applying a model-guided synthetic biology approach to quantitatively analyze the behavior of miRNA-mediated ceRNA regulation. "In mammalian cells, each type of miRNA can interact with dozens to hundreds of target RNA species – including protein-coding mRNAs, long non-coding RNAs and recently-discovered circular RNAs." Moreover, he explains, each RNA species can also interact with multiple miRNA species through various miRNA regulatory elements, or MREs, and the complex interaction network of miRNAs and their target RNAs has been shown to allow indirect cross-regulation between different competing endogenous RNAs (ceRNAs) by sequestering shared miRNAs, which is essential for regulating many biological functions. "However," he points out, "natural microRNA-ceRNA networks are complex and hard to perturb, which makes it difficult to quantitatively understand the mechanism of miRNA-mediated ceRNA regulation. Thus, we decided to implement an artificial miRNA-ceRNA system by transfecting synthetic gene circuits into human HEK293 cells to simulate the behavior of ceRNA regulation."
From smart phones and tablets to computer monitors and interactive TV screens, electronic displays are everywhere. As the demand for instant, constant communication grows, so too does the urgency for more convenient portable devices -- especially devices, like computer displays, that can be easily rolled up and put away, rather than requiring a flat surface for storage and transportation.
A new Tel Aviv University study, published recently in Nature Nanotechnology ("Light-emitting self-assembled peptide nucleic acids exhibit both stacking interactions and Watson–Crick base pairing"), suggests that a novel DNA-peptide structure can be used to produce thin, transparent, and flexible screens. The research, conducted by Prof. Ehud Gazit and doctoral student Or Berger of the Department of Molecular Microbiology and Biotechnology at TAU's Faculty of Life Sciences, in collaboration with Dr. Yuval Ebenstein and Prof. Fernando Patolsky of the School of Chemistry at TAU's Faculty of Exact Sciences, harnesses bionanotechnology to emit a full range of colors in one pliable pixel layer -- as opposed to the several rigid layers that constitute today's screens."
Our material is light, organic, and environmentally friendly," said Prof. Gazit. "It is flexible, and a single layer emits the same range of light that requires several layers today. By using only one layer, you can minimize production costs dramatically, which will lead to lower prices for consumers as well."
For the purpose of the study, a part of Berger's Ph.D. thesis, the researchers tested different combinations of peptides: short protein fragments, embedded with DNA elements which facilitate the self-assembly of a unique molecular architecture.
Peptides and DNA are two of the most basic building blocks of life. Each cell of every life form is composed of such building blocks. In the field of bionanotechnology, scientists utilize these building blocks to develop novel technologies with properties not available for inorganic materials such as plastic and metal."
Our lab has been working on peptide nanotechnology for over a decade, but DNA nanotechnology is a distinct and fascinating field as well. When I started my doctoral studies, I wanted to try and converge the two approaches," said Berger. "In this study, we focused on PNA - peptide nucleic acid, a synthetic hybrid molecule of peptides and DNA. We designed and synthesized different PNA sequences, and tried to build nano-metric architectures with them."
Harvard researchers, probing the mystery of how some bacteria move across surfaces, have discovered a kind of rotary motor in the bacterium Flavobacterium johnsoniae. The finding came as Abhishek Shrivastava, a postdoctoral fellow working in the lab of Howard Berg, the Herchel Smith Professor of Physics and a professor of molecular and cellular biology, was investigating how many types of bacteria, including F. johnsoniae, are able to move without the aid of flagella or pili. The discovery is described in a recently published paper in Current Biology.
“If you look at the diversity of the bacterial world, there are many bacteria — including F. johnsoniae — that do not have flagella or pili, yet they move quite easily over surfaces, and travel long distances. This movement is called ‘bacterial gliding,’” Shrivastava said. “To move by this process, bacteria require a constant influx of energy. We wanted to find out how bacterial gliding takes place and what could be a motor for gliding.”
Though researchers had long observed bacterial gliding, the precise mechanics underlying the behavior remained a mystery.
The first clues came a few years ago, Shrivastava said, when researchers discovered that the rod-shaped Flavobacteria are actually bristling with tiny filaments, made up of a protein called SprB. These filaments are required for motility.
Shrivastava and others used an antibody “glue” to pin one of the filaments down to a glass plate and found that when they are held down, the cells pinwheel around the point of attachment. If a small, plastic bead were attached to the filament, they found that it would also rotate. The torque generated by the gliding motor was calculated to be large, and comparable to torque generated by motors that drive flagellar filaments.
Though not the only one found in nature — a similar motor powers the flagella found on bacteria like E. coli — the rotary motor discovered by Shrivastava and colleagues appears to be distinct from others. “If you look at the genome sequence of this bacterium, it does not have the genes that make the proteins used to build the flagellar motor,” Shrivastava said. “It could be that some of the components are similar, but we are probably looking at some novel proteins. So we want to understand what makes up the nuts and bolts of this motor.”
Going forward, Berg said, researchers still have many questions to answer. “The flagellar motor has about 20 different kinds of parts, from a drive shaft to a rotary bearing and a universal joint — that kind of machinery is in this bug, but we have no idea what that is. What we need to do now is somehow pull it out and understand the architecture of this motor.
Scientists are using previously top-secret technology to zoom through the human body down to the level of a single cell. Scientists are also using cutting-edge microtome and MRI technology to examine how movement and weight bearing affects the movement of molecules within joints, exploring the relationship between blood, bone, lymphatics and muscle.
UNSW biomedical engineer Melissa Knothe Tate is using previously top-secret semiconductor technology to zoom through organs of the human body, down to the level of a single cell.
A world-first UNSW collaboration that uses previously top-secret technology to zoom through the human body down to the level of a single cell could be a game-changer for medicine, an international research conference in the United States has been told.
The imaging technology, developed by high-tech German optical and industrial measurement manufacturer Zeiss, was originally developed to scan silicon wafers for defects.
UNSW Professor Melissa Knothe Tate, the Paul Trainor Chair of Biomedical Engineering, is leading the project, which is using semiconductor technology to explore osteoporosis and osteoarthritis.
Using Google algorithms, Professor Knothe Tate -- an engineer and expert in cell biology and regenerative medicine -- is able to zoom in and out from the scale of the whole joint down to the cellular level "just as you would with Google Maps," reducing to "a matter of weeks analyses that once took 25 years to complete."
Her team is also using cutting-edge microtome and MRI technology to examine how movement and weight bearing affects the movement of molecules within joints, exploring the relationship between blood, bone, lymphatics and muscle. "For the first time we have the ability to go from the whole body down to how the cells are getting their nutrition and how this is all connected," said Professor Knothe Tate. "This could open the door to as yet unknown new therapies and preventions."
Professor Knothe Tate is the first to use the system in humans. She has forged a pioneering partnership with the US-based Cleveland Clinic, Brown and Stanford Universities, as well as Zeiss and Google to help crunch terabytes of data gathered from human hip studies. Similar research is underway at Harvard University and Heidelberg in Germany to map neural pathways and connections in the brains of mice.
Differences in male and female rodent sexual behaviors are programmed during brain development, but how exactly this occurs is not clear. In the preoptic area (POA) of the brain—a region necessary for male sex behavior—the female phenotype results from repression of male-linked genes by DNA methylation, according to a study published today (March 30, 2015) in Nature Neuroscience.
There is very little known about how the brain is masculinized—and even less about how it is feminized—even though the question has been studied for more than 50 years, said Bridget Nugent, study author and now a postdoctoral fellow at the University of Pennsylvania. These sex differences in the brain are programmed toward the end of fetal development, through to one week after birth in rodents. In males, testicular hormones drive masculinization of the brain; this was thought to occur by direct induction of gene expression by hormone-associated transcription factors. Because a feminized brain occurred in the absence of ovarian hormone signals, most researchers assumed that the female brain and behavior was a sort of default state, programmed during development when no male hormones are present. But the downstream mechanisms of how hormones can modify gene expression were not previously known.
“This study reveals that DNA methylation plays an important role in regulating sexual differentiation,” said Nirao Shah, who also studies the neural basis for sex-specific behaviors at the University of California, San Francisco, but was not involved with the work.
“Our understanding that the female state of the brain is the default still stands. What changes now, because of this study, is our thinking as to how the default state is preserved,” said Geert de Vries, director of the Neuroscience Institute at Georgia State University who studies how sex influences the developing brain but was not involved in the work. “The authors show that there is active repression of the masculine brain program, and that is really a novel idea.”
In other words, male hormones unleash the male program. “It’s an emancipation, you might say, of these genes that are suppressed by the female. So, evolutionarily, this evolved a lot differently than we thought,” said study author Margaret McCarthy, a professor of pharmacology at the University of Maryland School of Medicine.
Nugent, McCarthy, and their colleagues demonstrated that activity of DNA methyltransferase (Dnmt) enzymes—which control the methylation of DNA, and therefore gene repression—was lower in the POA of the brain in male versus female rats during the sensitive period. Treating newborn female rats with male hormones resulted in male-level Dnmt activity, but had no effect on older rats. Typical female rats also had twice the levels of fully methylated CpG sites throughout their genomes compared to either male or masculinized female rats.
The team was then able to drive both male morphology within the POA and male copulation behavior in female rats by administering small molecule inhibitors of Dnmts directly into the brain at birth.
While giving male hormones to females only modified female rodent sexual behavior during the critical period, inhibiting Dnmts led to a male phenotype even after the sensitive window had closed, 10 days after birth. The researchers also found that knocking out one of the Dnmt enzymes in a mouse model several days after birth—outside of the sensitive development window—resulted in female mice exhibiting male copulation behaviors.
Scientists have found a way to boil water faster. The technology works by coating a heating element with a virus found on tobacco plants. The coating dramatically reduces the size and number of bubbles that form around the element as it gets warmer. Air pockets caused by bubbles temporarily insulate heating elements from the surrounding water, slowing down the transfer of heat. A coating made from the tobacco virus tripled the efficiency of boiling water, scientists said, which could save vast quantities of energy in industrial power plants or large-scale electronic cooling systems.
“Even slight improvements to technologies that are used so widely can be quite impactful,” said Matthew McCarthy, an engineer at Drexel University in Pennsylvania. Controlling the formation of bubbles would also help guard against a scenario called “critical heat flux” that is undesirable – sometimes disastrous – in industrial boilers. This happens when so many bubbles are forming that they merge into a blanket surrounding the element, meaning that it can no longer transfer heat to the water.
“What happens then is the dry surface gets hotter and hotter, like a pan on the stove without water in it,” said McCarthy. “This failure can lead to the simple destruction of electronic components, or in power plant cooling applications, the catastrophic meltdown of a nuclear reactor.” To counteract this effect, scientists have been attempting to develop surfaces that repel bubbles and keep the boiling surface wet. McCarthy’s team has identified tobacco mosaic virus, which is roughly pencil-shaped, as the perfect structure for wicking moisture downwards towards a surface.
The team has developed a genetically modified strain of the virus, with “molecular hooks” allowing it to adhere to nearly any surface. The researchers grow tobacco plants in the lab and infect them with the modified tobacco mosaic virus. “When the plants are really sick, we put them in the blender and you get a sort of green soup,” said McCarthy.
After several rounds of centrifuging and chemical separation, which takes two days, the scientists are left with a perfectly clear solution of concentrated virus. When poured over a surface, the virus self-assembles into a layer of nano-tendrils, each pointing upward like a blade of grass.
The latest DNA nanodevices created at the Technische Universitaet Muenchen (TUM) - including a robot with movable arms, a book that opens and closes, a switchable gear, and an actuator - may be intriguing in their own right, but that's not the point. They demonstrate a breakthrough in the science of using DNA as a programmable building material for nanometer-scale structures and machines. Results published in the journalScience reveal a new approach to joining - and reconfiguring - modular 3D building units, by snapping together complementary shapes instead of zipping together strings of base pairs. This not only opens the way for practical nanomachines with moving parts, but also offers a toolkit that makes it easier to program their self-assembly.
The field popularly known as "DNA origami," in reference to the traditional Japanese art of paper folding, is advancing quickly toward practical applications, according to TUM Prof. Hendrik Dietz. Earlier this month, Dietz was awarded Germany's most important research award, the Gottfried Wilhelm Leibniz Prize, for his role in this progress.
In recent years, Dietz and his team have been responsible for major steps in the direction of applications: experimental devices including a synthetic membrane channel made from DNA; discoveries that cut the time needed for self-assembly processes from a week to a few hours and enable yields approaching 100%; proof that extremely complex structures can be assembled, as designed, with subnanometer precision. Yet all those advances employed "base-pairing" to determine how individual strands and assemblies of DNA would join up with others in solution. What's new is the "glue."
"Once you build a unit with base pairs," Dietz explains, "it's hard to break apart. So dynamic structures made using that approach tended to be structurally simple." To enable a wider range of DNA nanomachines with moving parts and potentially useful capabilities, the team adapted two more techniques from nature's biomolecular toolkit: the way proteins use shape complementarity to simplify docking with other molecules, and their tendency to form relatively weak bonds that can be readily broken when no longer needed.
For the experiments reported in Science, Dietz and his co-authors took inspiration from a mechanism that allows nucleic acid molecules to bond through interactions weaker than base-pairing. In nature, weak bonds can be formed when the RNA-based enzyme RNase P "recognizes" so-called transfer RNA; the molecules are guided into close enough range, like docking spacecraft, by their complementary shapes.
The new technology from Dietz's lab imitates this approach. To create a dynamic DNA nanomachine, the researchers begin by programming the self-assembly of 3D building blocks that are shaped to fit together. A weak, short-ranged binding mechanism called nucleobase stacking can then be activated to snap these units in place. Three different methods are available to control the shape and action of devices made in this way.
What this has given us is a tiered hierarchy of interaction strengths," Dietz says, "and the ability to position - precisely where we need them - stable domains that can recognize and interact with binding partners." The team produced a series of DNA devices - ranging from micrometer-scale filaments that might prefigure technological "flagella" to nanoscale machines with moving parts - to demonstrate the possibilities and begin testing the limits.
For example, transmission electron micrographs of a three-dimensional, nanoscale humanoid robot confirm that the pieces fit together exactly as designed. In addition, they show how a simple control method - changing the concentration of positive ions in solution - can actively switch between different configurations: assembled or disassembled, with "arms" open wide or resting at the robot's side.
Handheld instrument does real-time nucleic acid testing to check if you're getting the fish you paid for.
Appreciate a well-cooked tuna steak or salmon wrapped in a sushi roll? There’s a good chance the fish sitting on your plate or in your grocery store’s seafood case is not what its label says it is, according to the ocean conservancy group Oceana. So you could be paying a premium for red snapper that’s really just plain old tilapia.
University of South Florida scientists have now made a handheld device that could help fight such seafood fraud. The instrument genetically verifies whether fish being called grouper is really grouper or less expensive, potentially harmful substitutes like catfish or mackerel. A quarter of grouper in the United States is mislabeled, according to Oceana, making it the fourth most commonly mislabeled fish in the country. Snapper was the most commonly mislabeled.
The Oceana study found that 33 percent of the 1200-plus seafood samples taken nationwide were mislabeled. This seafood fraud costs fishermen, the U.S. seafood industry, and consumers $20–25 billion annually, it calculates. In addition, fraud allows illegally caught fish to slip into the legal seafood trade and prevents consumers from making ecologically-friendly choices.
Today’s DNA barcoding methods for seafood identification analyze a sample’s DNA. While the price of gene sequencing has dropped in recent years, it still takes days and expensive lab equipment for accurate genetic identitification. The new device, on the other hand, purifies and amplifies a seafood sample’s RNA, or ribonucleic acid. The assay is simpler and works within 90 minutes. USF marine science professor John Paul and his colleagues have developed such assays to identify several microorganisms, and have now applied the technology to seafood identification.
The researchers described the technology and its application in the journal Food Control. They are now developing assays for other commercially relevant species, and they’re also commercializing it through Tampa-based spinoff PureMolecular LLC. That company plans to start selling the machines for US $2000 by this summer, Reuters reports.
Astronomers have discovered an outburst from a star thought to be in the earliest phase of its development.
Using data from orbiting observatories, including NASA's Spitzer Space Telescope, and ground-based facilities, an international team of astronomers has discovered an outburst from a star thought to be in the earliest phase of its development. The eruption, scientists say, reveals a sudden accumulation of gas and dust by an exceptionally young protostar known as HOPS 383.
Stars form within collapsing fragments of cold gas clouds. As the cloud contracts under its own gravity, its central region becomes denser and hotter. By the end of this process, the collapsing fragment has transformed into a hot central protostar surrounded by a dusty disk roughly equal in mass, embedded in a dense envelope of gas and dust. Astronomers call this a "Class 0" protostar.
"HOPS 383 is the first outburst we've ever seen from a Class 0 object, and it appears to be the youngest protostellar eruption ever recorded," said William Fischer, a NASA Postdoctoral Program Fellow at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
The Class 0 phase is short-lived, lasting roughly 150,000 years, and is considered the earliest developmental stage for stars like the sun. A protostar has not yet developed the energy-generating capabilities of a sun-like star, which fuses hydrogen into helium in its core. Instead, a protostar shines from the heat energy released by its contraction and by the accumulation of material from the disk of gas and dust surrounding it. The disk may one day develop asteroids, comets and planets.
Because these infant suns are thickly swaddled in gas and dust, their visible light cannot escape. But the light warms dust around the protostar, which reradiates the energy in the form of heat detectable by infrared-sensitive instruments on ground-based telescopes and orbiting satellites.
HOPS 383 is located near NGC 1977, a nebula in the constellation Orion and a part of its sprawling star-formation complex. Located about 1,400 light-years away, the region constitutes the most active nearby "star factory" and hosts a treasure trove of young stellar objects still embedded in their natal clouds.
A method of using light to activate or suppress neurons without requiring genetic modification (as in optogenetics) has been developed by scientists from the University of Chicago and the University of Illinois at Chicago. The new technique, described in the journal Neuron, uses targeted, heated gold nanoparticles. The researchers says it’s a significant technological advance with potential advantages over current optogenetic methods, including possible use in the development of therapeutics for diseases such as macular degeneration.
“This is effectively optogenetics without genetics,” said study senior author Francisco Bezanilla, PhD, Lillian Eichelberger Cannon Professor of biochemistry and molecular biology at the University of Chicago. “Many optogenetic experimental designs can now be applied to completely normal tissues or animals, greatly extending the scope of these research tools and possibly allowing for new therapies involving neuronal photostimulation.”
Optogenetics, the use of light to control neural activity, is a powerful technique with widespread use in neuroscience research. It involves genetically engineered neurons that express a light-responsive protein originally discovered in algae. This process allows scientists to stimulate individual neurons as well as neural networks with precise flashes of light. However, since optogenetics is reliant on genetic modification, its use is primarily limited to relatively few model organisms.
Bezanilla and his colleagues have previously shown that normal, non-genetically modified neurons can be activated by heat generated from pulses of near-infrared light. But this method lacked specificity and can damage cells. To improve the technique, they used gold nanoparticles — spheres only 20 nanometers in diameter. When stimulated with visible light, spherical gold nanoparticles absorb and convert light energy into heat. This heating effect can activate unmodified neurons. However, nanoparticles must be extremely close to a cell to produce any effect. Since the nanoparticles diffuse quickly, or get washed away in a neuron’s immediate environment, their efficacy is short-lived.
To get nanoparticles to stick, Bezanilla and his team coupled them to a synthetic molecule based on Ts1, a scorpion neurotoxin, which binds to sodium channels without blocking them. Neurons treated with Ts1-coupled nanoparticles in culture were readily activated by light. Untreated neurons were non-responsive.
Importantly, treated neurons could still be stimulated even after being continuously washed for 30 minutes, indicating that the nanoparticles were tightly bound to the cell surface. This also minimized potentially harmful elevated temperatures, as excess nanoparticles were washed away.
Neurons treated with Ts1-coupled nanoparticles could be stimulated repeatedly with no evidence of cell damage. Some individual neurons, targeted with millisecond pulses of light, produced more than 3,000 action potentials (spikes) over the span of 30 minutes, with no reduction in efficacy. In addition to cultured cells, Ts1-coupled nanoparticles were tested on complex brain tissue using thin slices of mouse hippocampus. In these experiments, the researchers were able to activate groups of neurons and then observe the resulting patterns of neural activity.
“The technique is easy to implement and elicits neuronal activity using light pulses. Therefore, stimulating electrodes are not required,” Bezanilla said. “Furthermore, with differently-shaped nanoparticles it can work in near-infrared as well as in visible wavelengths, which has many practical advantages in living animals. Thus far, most optogenetic tools have been limited to visible wavelengths.”
Many scientists believe tiny Martian microbes could flourish beneath the red planet's ice-cemented polar caps, or even in briny puddles of ultra-salty water—which they believe may be locked under Mars' soil in seasonal flows. But here's one important question about the possibility of life on Mars: What the heck does it eat?
According to Gary King, a biologist at Louisiana State University, the surprising answer could be a scentless, atmospheric gas: carbon monoxide. In a new study in the science journal PNAS, King has concluded that enough of the gas seeps into Mars's soil from the planet's atmosphere to feed hearty lifeforms. Such organisms which could look like Alkalilimnicola ehrlichii, a carbon monoxide-munching microbe found in California in 2007.
"This is a very important piece of work for Mars astrobiology," says Chris McKay, an astrobiologist at NASA who was not involved in King's research. "What this research means is that we now know of an energy source for microbial systems that could exist anywhere near the surface of Mars."
As McKay explains it, if you're going to have Earth-like life on Mars today, then you need to account for three things: nutrients, water, and energy. "Nutrients aren't really an issue," he says. "Mars has an abundance of carbon dioxide, nitrates, atmospheric nitrogen, and small amounts of many other nutrients. As for water, the theory that there could be these brines of saltwater under the soil has been around for years… What has always needed serious explanation is a potential source of energy. Now we have one."
For the most part, scientists had discounted the idea that hypothetical Martian microbes could get their energy from the planet's atmosphere. The reason is simple: Mars's atmosphere is incredibly thin and dominated by carbon dioxide, which is not a viable energy source. Only a tiny sliver of Mars's total atmosphere is carbon monoxide. It's created as sunlight breaks an oxygen atom off from atmospheric carbon dioxide.