The afternoon of May 6, 2010 was among the strangest in economic history. Starting at 2:42 p.m. EDT, the Dow Jones stock index fell 600 points in just 6 minutes. Its nadir represented the deepest single-day decline in that ...
Via Jacek Rajewski
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Recent research which has counted with the participation of the University of Granada Andalusian Institute of Earth Sciences has yielded new data on chemical gardens, mysterious formations produced when certain solid salts (copper sulfate, cobalt chloride) are added to an aqueous solution of sodium silicate.
Self-contained chemical gardens are formed through the self-assembly of mineral precipitates generated during certain chemical reactions, and they produce coloured forms that resemble vegetable structures. The first researcher who watched them was Johann Rudolf Glauber in 1646, and since then their formation has been a veritable mystery for the scientific community.
Besides their popularity in chemistry experiments for massive audiences, self-contained chemical gardens present analogies with a variety of natural systems, such as the ice channels formed underneath sea ice or the hydrothermal chimneys at the bottom of the oceans where it is believed that life on earth could have originated.
Their growth patterns are being studied today fundamentally to produce new self-structuring materials, or to understand their role in the origin of life, thanks to the energy they can store.
To produce a chemical garden in the lab, one typically introduces a metallic salt in an alkaline solution within a container. This leads to the growth of a series of irregular, tubular, multi-coloured structures thanks to the combined action of different physical processes (osmotic pressure, gravity effects, reactions and diffusion). The fact that these different processes interact in a complex way without any sort of control whatsoever provokes the irregularity, and above all the impossibility of reproducing the obtained three-dimensional forms obtained in this process. This precludes detailed understanding of the growth mechanisms of these structures.
In this context, researchers from the Non-linear Physical Chemistry Unity at the Free University of Brussels, and from the University of Granada Andalusian Institute of Earth Sciences have demonstrated that it is possible to obtain an important collection of reproducible structures by having the chemical gardens grow in a confined, almost bi-dimensional environment, by injecting a reagent inside another one between two horizontal plaques. The horizontal confinement of the reactor reduces the effects of gravity, while the injection of one reagent within another reduces the effects of osmotic pressure. Besides, the control of the initial concentrations of the reagents, and of the flow of injection allows for the study of the relative importance of chemical processes and transport within the selection of the shape in the precipitate.
The gamer punches in play after endless play of the Atari classic Space Invaders. Though an interminable chain of failures, the gamer adapts the gameplay strategy to reach for the highest score. But this is no human with a joystick in a 1970s basement. Artificial intelligence is learning to play Atari games. The Atari addict is a deep-learning algorithm called DQN.
This algorithm began with no previous information about Space Invaders—or, for that matter, the other 48 Atari 2600 games it is learning to play and sometimes master after two straight weeks of gameplay. In fact, it wasn't even designed to take on old video games; it is general-purpose, self-teaching computer program. Yet after watching the Atari screen and fiddling with the controls over two weeks, DQN is playing at a level that would humiliate even a professional flesh-and-blood gamer.
Volodymyr Mnih and his team of computer scientists at Google, who have just unveiled DQN in the journal Nature, says their creation is more than just an impressive gamer. Mnih says the general-purpose DQN learning algorithm could be the first rung on a ladder to artificial intelligence.
"This is the first time that anyone has built a single general learning system that can learn directly from experience to master a wide range of challenging tasks," says Demis Hassabis, a member of Google's team. The algorithm runs on little more than a powerful desktop PC with a souped up graphics card. At its core, DQN combines two separate advances in machine learning in a fascinating way. The first advance is a type of positive-reinforcement learning method called Q-learning. This is where DQN, or Deep Q-Network, gets its middle initial. Q-learning means that DQN is constantly trying to make joystick and button-pressing decisions that will get it closer to a property that computer scientists call "Q." In simple terms, Q is what the algorithm approximates to be biggest possible future reward for each decision. For Atari games, that reward is the game score.
Knowing what decisions will lead it to the high scorer's list, though, is no simple task. Keep in mind that DQN starts with zero information about each game it plays. To understand how to maximize your score in a game like Space Invaders, you have to recognize a thousand different facts: how the pixilated aliens move, the fact that shooting them gets you points, when to shoot, what shooting does, the fact that you control the tank, and many more assumptions, most of which a human player understands intuitively. And then, if the algorithm changes to a racing game, a side-scroller, or Pac-Man, it must learn an entirely new set of facts. That's where the second machine learning advance comes in. DQN is also built upon a vast and partially human brain-inspired artificial neural network. Simply put, the neural network is a complex program built to process and sort information from noise. It tells DQN what is and isn't important on the screen.
A team of space researchers working with data from the VLT in Chile has found via measuring the spectrum of a distant quasar by analyzing absorption lines in a galaxy in front of it, that there was no measurable change in the mass ratio of protons and electrons over a span of 12 billion years. In their paper published in the journal Physical Review Letters, the team, made up of two members from VU University in the Netherlands, and two members from Swinburne University of Technology in Australia, describe their findings and what it might mean for helping to explain dark energy.
Some theories suggest that dark energy, the mysterious force that has the universe continuing to expand, might be a field that evolves over time—if so, that might mean that some of the constants we take for granted, such as gravity, the speed of light, etc., might actually evolve as well. In this new effort, the researchers sought to test that idea by looking to see if the mass of protons or electrons (both of which are considered to be fundamental constants) and the ratio that describes their mass difference, changed over the course of billions of years.
To find out if that might be the case, the researchers looked to a distant quasar, one positioned behind a galaxy, relative to us. Quasars are still somewhat mysterious, described as celestial objects that emit a huge amount of energy and light—they look like stars, but some believe they actually hold black holes.
The researchers found that molecular hydrogen in the galaxy absorbed some of the light from the quasar allowing them to measure the energy transitions that occurred and thus the mass ratio of protons and electrons. Since the galaxy had been previously dated to 12.4 billion years ago, the light reaching it from the quasar must be even older. Their measurements showed no deviation (with a precision of 10–6) from the current constant, suggesting that the ratio has remained constant for at least 12 billon years. And this, the researchers claim, suggests that if dark energy is evolving, it has not done so over that time span.
Scientists are very excited over the recent discovery of a baby woolly rhino. The pristine specimen of the tiny extinct rhino--the only one of its type ever found--was discovered in permafrost along the bank of a stream in Siberia's Sakha Republic, The Siberian Times reported.
"At first we thought it was a reindeer's carcass, but after it thawed and fell down we saw a horn on its upper jaw and realized it must be a rhino," Alexander 'Sasha' Banderov, the hunter who made the discovery, told the Times. "The part of the carcass that stuck out of the ice was eaten by wild animals, but the rest of it was inside the permafrost and preserved well."
Scientists estimate that the rhino--which has been dubbed Sasha--was 18 months old when it died some 10,000 years ago, according to the Times. The specimen includes the animal's wool, an ear, an eye, nostrils, and skull and mouth.
"We are hoping Sasha the rhino will give us a lot of answers to questions of how they grew and developed, what conditions they lived in, and which of the modern day animals is the closest to them," Albert Protopopov, head of the Mammoth Fauna Department at the Academy of Sciences in Sakha Republic, told the Times. "We will concentrate on the DNA, because the carcass was kept frozen and chances are high we will get a better preserved DNA. We are hoping to report first results in a week or two." The genomic information might be used to recreate the species, similar to ongoing experiments with mammoth remains.
Residents of the eastern United States are enduring one of the most painfully cold periods in modern times. Since January, Syracuse, N.Y., has never had more days below zero. Bangor, Maine is witnessing its coldest month ever recorded. On Tuesday, Washington Dulles Airport experienced its most bitter morning measured so late in the season, plummeting to minus-4.
Yet, in what may seem like a paradox, the amount of wintertime cold air circulating around the Northern Hemisphere is shrinking to record low levels. This winter (2014-2015) is on track to see the most depleted cold air supply ever measured.
“We are still on pace to break the all-time record — no question about it,” says Jonathan Martin, a professor of meteorology at the University of Wisconsin-Madison. “Despite the brutal cold in the eastern U.S., the whole hemisphere is warmer this winter than it has ever been in history.”
Using an analysis of atmospheric temperature data from the National Center for Atmospheric Research, Martin has been tracking the size of the Northern Hemisphere cold pool during winter (December-February) over time. Specifically, he has examined the total area of the hemisphere covered by temperatures 23 degrees (-5 degrees Celsius) or lower at an altitude of about 5,000 feet, for the period 1948-1949 to present.
In a study accepted for publication in the Journal of Climate, Martin found that four of the five smallest Northern Hemisphere cold pools on record — averaged over the winter — have occurred since 2004. “Only 12 of the 43 winter seasons before 1990-1991 had below average seasonally averaged areas whereas 20 of 24 winter seasons have had below average seasonally averaged areas since,” the study says.
While some warming naysayers have attempted to discredit surface temperatures datasets because of adjustments made for quality control (the methods for which have been published in the peer reviewed journals and gained widespread acceptance), Martin says his results from upper air data are difficult to refute.
“Skeptics have jumped all over the surface data, but you can’t really do that with temperatures about a mile above sea level [analyzed from atmospheric data],” Martin says. “They make a pristine signal.”
Tiny DNA rings, carrying instructions for making a blood-detectable biomarker, can enter both healthy cells and cancer cells. But only cancer cells follow the recipe to make the biomarker.
The hunt for cancer biomarkers — substances whose presence in an individual’s blood or urine flags a probable tumor — is nothing new, said the study’s senior author, Sanjiv “Sam” Gambhir, professor and chair of radiology and director of the Canary Center at Stanford for Cancer Early Detection. High blood levels of prostate-specific antigen, for example, can signify prostate cancer, and there are also biomarkers that sometimes signal ovarian and colorectal cancer, he said.
But while various tumor types naturally secrete characteristic substances into the blood, the secreted substance is typically specific to the tumor type, with each requiring its own separate test. Complicating matters, these substances are also quite often made in healthy tissues, so a positive test result doesn’t absolutely mean a person actually has cancer. Or a tumor — especially a small one — simply may not secrete enough of the trademark substance to be detectable.
Gambhir’s team appears to have found a way to force any of numerous tumor types to produce a biomarker whose presence in the blood of mice unambiguously signifies cancer, because none of the rodents’ tissues — cancerous or otherwise — would normally be making it. This biomarker is a protein called secreted embryonic alkaline phosphatase. SEAP is naturally produced in human embryos as they form and develop, but it’s not present in adults.
To trick mice’s cancer cells into making SEAP and squirting it into the bloodstream, Gambhir and his colleagues used a DNA minicircle: a tiny, artificial, single-stranded DNA ring about 4,000 nucleotides in circumference — or roughly one-millionth as long as the DNA strand that would result from stretching all 23 chromosomes of the human genome end to end. The minicircles, which contained a single gene coding for SEAP, were mixed with a chemical agent to facilitate their uptake by both healthy and cancerous cells alike.
In front of the gene, the researchers inserted a short DNA sequence called a promoter. Promoters don’t code for protein production but, rather, are more like switches or rheostats telling the cell’s protein-manufacturing machinery whether and when to actually make the protein the gene codes for, and how much. Genes in every cell of all multicelled creatures are preceded by promoters. Although all of an individual’s cells contain precisely the same genes, how “on” the promoter is for a given gene in a given cell depends on varying local conditions within that particular cell at that particular time.
The particular promoter Gambhir and his colleagues snapped into the minicircle ahead of the SEAP gene normally regulates a gene called survivin that, in adults, is only “on” in cancer cells. So, in theory, the SEAP gene on the DNA minicircles Gambhir’s lab created would be produced only in cancer cells.
The survivin promoter has been used in gene-therapy experiments and is well-studied, Gambhir said. He noted that the survivin promoter is activated in a broad range of cancers, including breast, lung, ovarian and other major tumor types. For the study, the researchers injected cells from human melanoma cell lines into laboratory mice. Ordinarily, a mouse’s immune system would attack any injected human cell, cancerous or not. But these mice were immune-compromised, and soon numerous tiny tumors started to develop throughout their bodies, especially in their lungs. Other mice of the same strain were given otherwise-identical injections that didn’t contain the cancer cells; they didn’t develop tumors.
About two weeks later, the animals’ blood was checked to make sure their baseline levels of SEAP were zero. Then the investigators injected the minicircles intravenously into the animals’ tail veins and measured SEAP levels in the mice’s blood one, three, seven, 11 and 14 days later. Within 48 hours, SEAP was present in the blood of mice with tumors, but not in that of the tumor-free animals. That signal began declining in strength as early as 72 hours post-injection, fading to insignificance within the next two weeks or so. Its maximum strength varied with the total tumor volume in a mouse’s lungs, suggesting that the test may be sensitive not only to the presence of cancer but also to its extent.
The IBM computer Deep Blue’s 1997 defeat of world champion Garry Kasparov is one of the most famous events in chess history. But Kasparov himself and some computer scientists believe a more significant result occurred in 2005—and that it should guide how we use technology to make decisions and get work done.
In an unusual online tournament, two U.S. amateurs armed with three PCs snatched a $20,000 prize from a field of supercomputers and grandmasters. The victors’ technology and chess skills were plainly inferior. But they had devised a way of working that created a greater combined intelligence—one in which humans provided insight and intuition, and computers brute-force predictions.
Some companies are now designing software to foster just such man-machine combinations. One that owes its success to this approach is Palantir, a rapidly growing software company in Palo Alto, California, known for its close connections to intelligence agencies. Shyam Sankar, director of forward deployed engineering at the company, says Palantir’s founders became devotees while at PayPal, where they designed an automated system to flag fraudulent transactions. “It catches 80 percent of the fraud, the dumb fraud, but it’s not clever enough for the most sophisticated criminals,” says Sankar.
PayPal ended up creating software to enable humans to hunt for that toughest 20 percent themselves, in the form of a suite of analysis tools that allowed them to act on their own insights about suspicious activity in vast piles of data rather than wait for automated systems to discover it. Palantir, which received funding from the CIA, now sells similar data-analysis software to law enforcement, banks, and other industries.
Sankar describes Palantir’s goal as fostering “human-computer symbiosis,” a term adapted from J.C.R. Licklider, a psychologist and computer scientist who published a prescient essay on the topic in 1960. Sankar contrasts that with what he calls the “AI bias” now dominant in the tech industry. “We focus on helping humans investigate hypotheses,” says Sankar. That’s only possible if analysts have tools that let them creatively examine data from every angle in search of those “aha” moments.
In practice, Palantir’s software gives the user tools to explore interconnected data and tries to present the information visually, often as maps that track to how people think. One bank bought the software in order to detect rogue employees stealing or leaking sensitive information. The detective work was guided by when and where employees badged into buildings, and by records of their digital activities on the company’s network. “This is contrary to automated decision making, when an algorithm figures everything out based on past data,” says Ari Gesher, a Palantir engineer. “That works great. Except when the adversary is changing. And many classes of modern problems do have this adaptive adversary in the mix.”
Palantir’s devotion to human–computer symbiosis seems to be working. The nine-year-old company now has 1,200 employees and is expanding into new industries such as health care. Forbes estimated that it was on course for revenues of $450 million in 2013.
When making simple decisions, neurons in the brain apply the same statistical trick used by Alan Turing to help break Germany’s Enigma code during World War II, according to a new study in animals by researchers at Columbia University’s Mortimer B. Zuckerman Mind Brain Behavior Institute and Department of Neuroscience. Results of the study were published Feb. 5 in Neuron.
As depicted in the film “The Imitation Game,” Alan Turing and his team of codebreakers devised the statistical technique to help them decipher German military messages encrypted with the Enigma machine. The technique today is called Wald’s sequential probability ratio test, after Columbia professor Abraham Wald, who independently developed the test to determine if batches of munitions should be shipped to the front or if they contained too many duds.
Finding pairs of messages encrypted with the same Enigma settings was critical to unlocking the code. Turing’s statistical test, in essence, decided as efficiently as possible if any two messages were a pair.
The test evaluated corresponding pairs of letters from the two messages, aligned one above the other (in the film, codebreakers are often pictured doing this in the background, sliding messages around on grids). Although the letters themselves were gibberish, Turing realized that Enigma would preserve the matching probabilities of the original messages, as some letters are more common than others.
The codebreakers assigned values to aligned pairs of letters in the two messages. Unmatched pairs were given a negative value, matched pairs a positive value.
Most of us think ants are unsanitary; it certainly seems that way when they’ve invaded our homes. But scientists have spotted ant behaviors that show that the insects are cleaner than you might think. Some ant species are known to form “kitchen middens” outside their nests, full of waste and fecal material. And in some species of leaf-cutting ants, only specialist waste management workers go into refuse chambers.
Black garden ants (Lasius niger), a common species in Europe, make those refuse piles outside their nests, filling them with food remains, corpses of dead nest-mates and other refuse. But Tomer Czaczkes and colleagues at the University of Regensburg in Germany spotted distinct, dark patches within the nests of ants in the lab. The team thought the patches might be where ants were depositing fecal matter but had to set up an experiment to test the idea. Their study was published February 18 inPLOS ONE.
The researchers constructed 21 plaster nests in the lab, each with a group of 150 to 300 ants living inslde. They then fed the ants a sugar solution laced with one color (red or blue) and a protein food laced with the other color. Once a week for two months, the nests were photographed, and a person who was unfamiliar with the experiment recorded the locations of dark patches in the nests and what color those patches were.
Researchers set up 21 plaster nests that were inhabited by 150 to 300 worker ants for two months. They identified toilet areas by lacing the ants’ food with a colored solution.
Every nest had at least one dark patch, and some had as many as four. The patches were always the same color as the sugar solution and were mostly in the nest corners. The patches never contained nest debris, dead ants or colored bits of the protein food source — those were all relegated to the garbage dump outside the nest. And the ants formed those patches whether there were lots of ants in the nest or not.
Where did our species come from, and how did we get from there to everywhere? A 55,000-year-old partial skull found in Manot Cave in western Galilee in January 2015 suggests that modern humans were in the Levant around the same time as Neanderthals.
Now, a pair of American archaeologists claim to have uncovered the route those early Homo sapiens took on their way to populating the planet. By following the broken trail of stone tools that modern humans left behind like bread crumbs marking their path, researchers propose that our ancestors took a circuitous path through Arabia, pausing there for some 50,000 years when it was a green oasis. Then they journeyed on to the Middle East, where they first encountered Neanderthals.
Stylistic and manufacturing similarities, the archaeologists say, connect the dots between tools made first in the Nile Valley of Egypt, then in the Arabian Peninsula, and, finally, in Israel. Those tools became progressively smaller and more sophisticated, similar to the evolution of mobile phones today.
"Archaeologists have always focused so much on 'out of Africa and into the Middle East' that we've missed an entire chapter of the human expansion in Arabia," says archaeologist Jeffrey Rose of the Ronin Institute, based in New Jersey, co-author of a new report published this month in Quartär.
University of Tokyo researchers have developed a "fever alarm armband," a flexible, self-powered wearable device that sounds an alarm in case of high body temperature. This armband will be presented at the 2015 IEEE International Solid State Circuits Conference, San Francisco, on 22-26 February, 2015. The flexible organic components developed for this device are well-suited to wearable devices that continuously monitor vital signs including temperature and heart rate for applications in healthcare settings.
In a study published in the January 2015 issue of The American Naturalist (http://www.jstor.org/stable/10.1086/679106), Gustavo A. Londoño, Duván Garcia, and Manuel Sánchez Martínez report a novel nesting strategy observed in a tropical lowland bird that inhabits an area with very high losses to nest predators.
Remember the Titan (Landing): Ten years ago today, Jan. 14, 2005, the Huygens probe touched down on Saturn's largest moon, Titan.
A new research has found that antibodies that protect against H7N9 avian flu have been isolated in individuals who received seasonal flu vaccinations. The research conducted by University Of Chicago Medical Centre explained that antibodies protection, which emerged in China account for a small percentage of the total immune response, but appear to neutralise H7 viruses and represent promising new targets for therapeutic development against a wide range of influenza strains.
Patrick Wilson, co-senior author said that the normal immune response to flu vaccination offers protection against dangerous and highly unique strains of influenza such as H7N9, so they will now develop ways of amplifying this response. Carole Henry, author of the study said that they observed that antibodies induced by flu vaccination offer cross-protection against H7N9, although they are not always protective, H7-reactive antibodies can be found in almost everyone that's been vaccinated. Wilson concluded that they will exploit this response on a larger scale to make vaccines or therapeutics that offer broad protection against influenza strains.
The study is published in the journal of Clinical Investigation.
Feeling a bit nippy? For now you'll have to stick to your hat and scarf to warm up, but one day some antifreeze proteins from a fish or a tick might do the trick. In a preliminary study published Wednesday in PLOS ONE, researchers report using specially bred mice -- ones spliced with the genes that give ticks antifreeze cells -- to show that mammals can benefit from the proteins that other species use to keep from icing over.
Ticks aren't the only species with so-called antifreeze proteins, which help keep creatures that don't moderate their own body temperatures from ending up with frozen cells (or, in some cases, just keep that freezing from having harmful effects) by preventing the formation of ice crystals inside tissue. But lead study author Erol Fikrig, a professor of medicine at Yale and an investigator for the Howard Hughes Medical Institute, focuses on the ticks and their antifreeze properties in particular in his lab.
Ticks have a protein called IAFGP that kicks in during winter. Fikrig and his colleagues wondered if it could be harnessed by mammals.
"The most typical thing that happens to us in the cold is frostbite," he said. So after breeding genetically modified mice to produce IAFGP, the lab tested their tolerance to cold.
In both skin sample tests (where they stored skin cell samples in just above freezing temperatures for several days) and tests on living mice (where tails were placed in a cooling solution for seven days), the mice that produced IAFGP showed less frostbite. Sixty percent of the treated mice had no frostbite at all on their tails at the end of the trial, as compared to 11 percent of the normal mice.
The rate at which tropical forests were cut, burned or otherwise lost from the 1990s through the 2000s accelerated by 62 percent, according to a new study which dramatically reverses a previous estimate of a 25 percent slowdown over the same period. That previous estimate, from the U.N.'s Food and Agriculture Organization's (FAO) Forest Resource Assessment, was based on a collection of reports from dozens of countries. The new estimate, in contrast, is based on vast amounts of Landsat image data which directly record the changes to forests over 20 years.
"Several satellite-based local and regional studies have been made for changing rates of deforestation [during] the 1990s and 2000s, but our study is the first pan-tropical scale analysis," explains University of Maryland, College Park, geographer Do-Hyung Kim, lead author of the new study accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.
Kim and his University of Maryland colleagues Joseph Sexton and John Townshend looked at 34 forested countries which comprise 80 percent of forested tropical lands. They analyzed 5,444 Landsat scenes from 1990, 2000, 2005 and 2010 with a hectare-scale (100 by 100 meter) resolution to determine how much forest was lost and gained. Their procedure was fully automated and computerized both to make the huge datasets manageable and to minimize human error.
They found that during the 1990-2000 period the annual net forest loss across all the countries was 4 million hectares (15,000 square miles) per year. During the 2000-2010 period, the net forest loss rose to 6.5 million hectares (25,000 square miles) per year - a 62 percent increase is the rate of deforestation. That last rate is the equivalent to clear cutting an area the size of West Virginia or Sri Lanka each year, or deforesting an area the size of Norway every five years.
In terms of where the deforestation was happening, they found that tropical Latin America showed the largest increase of annual net loss of 1.4 million hectares (5,400 square miles) per year from the 1990s to the 2000s, with Brazil topping the list at 0.6 million hectares (2,300 square miles) per year. Tropical Asia showed the second largest increase at 0.8 million hectares (3,100 square miles) per year, with similar trends across the countries of Indonesia, Malaysia, Cambodia, Thailand and the Philippines. Tropical Africa showed the least amount of annual net forest area loss. Still, there was a steady increase of net forest loss in tropical Africa due to cutting primarily in Democratic Republic of Congo and Madagascar.
Scientists have generated mature, functional skeletal muscles in mice using a new approach for tissue engineering. The scientists grew a leg muscle starting from engineered cells cultured in a dish to produce a graft. The subsequent graft was implanted close to a normal, contracting skeletal muscle where the new muscle was nurtured and grown. In time, the method could allow for patient-specific treatments for a large number of muscle disorders.
The scientists used muscle precursor cells -- mesoangioblasts -- grown in the presence of a hydrogel (support matrix) in a tissue culture dish. The cells were also genetically modified to produce a growth factor that stimulates blood vessel and nerve growth from the host. Cells engineered in this way express a protein growth factor that attracts other essential cells that give rise to the blood vessels and nerves of the host, contributing to the survival and maturation of newly formed muscle fibres. After the graft was implanted onto the surface of the skeletal muscle underneath the skin of the mouse, mature muscle fibres formed a complete and functional muscle within several weeks. Replacing a damaged muscle with the graft also resulted in a functional artificial muscle very similar to a normal Tibialis anterior.
Tissue engineering of skeletal muscle is a significant challenge but has considerable potential for the treatment of the various types of irreversible damage to muscle that occur in diseases like Duchenne muscular dystrophy. So far, attempts to re-create a functional muscle either outside or directly inside the body have been unsuccessful. In vitro-generated artificial muscles normally do not survive the transfer in vivo because the host does not create the necessary nerves and blood vessels that would support the muscle's considerable requirements for oxygen.
"The morphology and the structural organisation of the artificial organ are extremely similar to if not indistinguishable from a natural skeletal muscle," says Cesare Gargioli of the University of Rome, one of the lead authors of the study.
In future, irreversibly damaged muscles could be restored by implanting the patient's own cells within the hydrogel matrix on top of a residual muscle, adjacent to the damaged area. "While we are encouraged by the success of our work in growing a complete intact and functional mouse leg muscle we emphasize that a mouse muscle is very small and scaling up the process for patients may require significant additional work," comments EMBO Member Giulio Cossu, one of the authors of the study. The next step in the work will be to use larger animal models to test the efficacy of this approach before starting clinical studies.
The world's first attempt to transplant a human head will be launched this year at a surgical conference in the US. The move is a call to arms to get interested parties together to work towards the surgery.
The idea was first proposed in 2013 by Sergio Canavero of the Turin Advanced Neuromodulation Group in Italy. He wants to use the surgery to extend the lives of people whose muscles and nerves have degenerated or whose organs are riddled with cancer. Now he claims the major hurdles, such as fusing the spinal cord and preventing the body's immune system from rejecting the head, are surmountable, and the surgery could be ready as early as 2017.
Canavero plans to announce the project at the annual conference of the American Academy of Neurological and Orthopaedic Surgeons (AANOS) in Annapolis, Maryland, in June. Is society ready for such momentous surgery? And does the science even stand up?
The first successful head transplant, in which one head was replaced by another, was carried out in 1970. A team led by Robert White at Case Western Reserve University School of Medicine in Cleveland, Ohio, transplanted the head of one monkey onto the body of another. They didn't attempt to join the spinal cords, though, so the monkey couldn't move its body, but it was able to breathe with artificial assistance. The monkey lived for nine days until its immune system rejected the head. Although few head transplants have been carried out since, many of the surgical procedures involved have progressed. "I think we are now at a point when the technical aspects are all feasible," says Canavero.
This month, he published a summary of the technique he believes will allow doctors to transplant a head onto a new body (Surgical Neurology International,doi.org/2c7). It involves cooling the recipient's head and the donor body to extend the time their cells can survive without oxygen. The tissue around the neck is dissected and the major blood vessels are linked using tiny tubes, before the spinal cords of each person are cut. Cleanly severing the cords is key, says Canavero.
The recipient's head is then moved onto the donor body and the two ends of the spinal cord – which resemble two densely packed bundles of spaghetti – are fused together. To achieve this, Canavero intends to flush the area with a chemical called polyethylene glycol, and follow up with several hours of injections of the same stuff. Just like hot water makes dry spaghetti stick together, polyethylene glycol encourages the fat in cell membranes to mesh.
Next, the muscles and blood supply would be sutured and the recipient kept in a coma for three or four weeks to prevent movement. Implanted electrodes would provide regular electrical stimulation to the spinal cord, because research suggests this can strengthen new nerve connections.
When the recipient wakes up, Canavero predicts they would be able to move and feel their face and would speak with the same voice. He says that physiotherapy would enable the person to walk within a year. Several people have already volunteered to get a new body, he says.
At the annual meeting of the American Association for the Advancement of the Sciences in San Jose, scientists debated whether sending radio messages to possible alien civilizations on distant planets would be a good idea. Such signals or messages could be sent with the help of signals aimed at areas in our galaxy where earth-like planets and life are more likely to also exist. Steven Hawking seems to be totally against this initiative, calling it catastrophic. He explained back in 2010 that alien civilizations, some of which may be more technologically advanced than us may thus come to our planet and exploit its resources. “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans,” Hawking explained.
As far as the communication method is concerned, scientists from the Search for Extraterrestrial Intelligence (SETI) are of the opinion that sending an active signal in order to search for alien life, an action called Messages to Extraterrestrial Intelligence (METI), is far more efficient than using radio telescopes for detecting unusual signals.
METI signals are meant to be sent to parts of other galaxies where planets that resemble Earth’s structure could contain life. The impressive discoveries made by the Kepler space telescope, which found more than 1,000 Earth-like planets in nearby galaxies encouraged the messaging initiative, despite older warnings made by scientists.
Among less threatening concerns is the one belonging to radio astronomer Frank Drake, who said the METI signals are a waste of time right now. He explained that what humans are attempting through these signals is comparable to trying to send emails to unknown email addresses belonging to someone you don’t even know.
Hawking’s warnings received even more attacks coming from colleagues who are more than intrigued by the SETI activity. Dr. Douglas A. Vakoch, Director of the Interstellar Message Composition program replied: “If we can come to understand the messages of an independently evolved civilization, if we can get a glimpse into how they experience their worlds, we will have a mirror to hold up to ourselves, giving us a deeper appreciation of what makes us distinctively human.”
When diagnosing a case of Ebola, time is of the essence. However, existing diagnostic tests take at least a day or two to yield results, preventing health care workers from quickly determining whether a patient needs immediate treatment and isolation.
A new test from MIT researchers could change that: The device, a simple paper strip similar to a pregnancy test, can rapidly diagnose Ebola, as well as other viral hemorrhagic fevers such as yellow fever and dengue fever.
“As we saw with the recent Ebola outbreak, sometimes people present with symptoms and it’s not clear what they have,” says Kimberly Hamad-Schifferli, a visiting scientist in MIT’s Department of Mechanical Engineering and a member of the technical staff at MIT’s Lincoln Laboratory. “We wanted to come up with a rapid diagnostic that could differentiate between different diseases.”
Hamad-Schifferli and Lee Gehrke, the Hermann L.F. von Helmholtz Professor in MIT’s Institute for Medical Engineering and Science (IMES), are the senior authors of a paper describing the new device in the journal Lab on a Chip. The paper’s lead author is IMES postdoc Chun-Wan Yen, and other authors are graduate student Helena de Puig, IMES postdoc Justina Tam, IMES instructor Jose Gomez-Marquez, and visiting scientist Irene Bosch.
Currently, the only way to diagnose Ebola is to send patient blood samples to a lab that can perform advanced techniques such as polymerase chain reaction (PCR), which can detect genetic material from the Ebola virus. This is very accurate but time-consuming, and some areas of Africa where Ebola and other fevers are endemic have limited access to this kind of technology.
The new device relies on lateral flow technology, which is used in pregnancy tests and has recently been exploited for diagnosing strep throat and other bacterial infections. Until now, however, no one has applied a multiplexing approach, using multicolored nanoparticles, to simultaneously screen for multiple pathogens.
When the universe was young, some black holes were terribly greedy. One of these black holes gobbled the mass of 12 billion suns by the time the universe was only about 860 million years old. This monster is the most massive known black hole in the early universe, clocking in at roughly six times as massive as other black holes from its time, researchers report in the Feb. 26, 2015 issue of Nature.
To estimate the mass, Xue-Bing Wu, an astrophysicist at Peking University in Beijing, and colleagues measured the speed at which gas swirls around the black hole. Today, each black hole this massive lives in the center of a galaxy containing several trillion stars. Since such galactic giants formed only relatively recently, the discovery suggests that some supermassive black holes grew much faster than the galaxies they inhabit.
The more a rat helps another, the more it'll receive in return, a new study says—the first such discovery in non-humans. Rats can remember acts of kindness by other rats—and treat them accordingly, a new study says.
In experiments, Norwegian rats were most helpful to individuals that had previously helped them—perhaps to try and secure their assistance again, scientists suggest. While rats are known to cooperate and assist one another, rewarding another rat for no immediate gain wasn't thought to be common behavior. In fact, a rat rewarding a fellow rat for help—an act called direct reciprocation—is a first among nonhumans, said study co-author Michael Taborsky, a behavioral ecologist at the University of Bern in Switzerland.
The study was based on female captive Norwegian rats' preferences for two types of food: bananas and carrots. For these wild-type rats, bananas are a favorite—carrots, not so much.
In the experiment, each of a pair of rat helpers could deliver one of these tidbits to a rat in another enclosure by pulling on a stick (Video). Eventually, the receiving rat would recognize each helper as either a high-quality helper (if it delivered bananas) or a low-quality helper (if it delivered carrots).
Then, scientists switched the rats' places, so the rats on the receiving end were now able to pull on a stick that would deliver cereal flakes to a certain helper. The rats that had given bananas generally received cereal more quickly and more often than carrot-givers. In the same vein, the rats that had given carrots got cereal less often than the banana-givers did.
Bionic hands are go. Three men with serious nerve damage had their hands amputated and replaced by prosthetic ones that they can control with their minds.
This approach works because the prosthetic hands come with their own power source. Aszmann's patients plug their hands in to charge every night. Relying on electricity from the grid to power the hand means all the muscles and nerves need do is send the right signals to a prosthetic.
First they practized activating the muscle using an armband of sensors that picked up on the electrical activity. Then they moved on to controlling a virtual arm. Finally, Aszmann amputated their hands, and replaced them with a standard prosthesis under the control of the muscle and sensors.
"I was impressed and first struck with the surgical innovation," says Dustin Tyler of the Louis Stokes Veterans Affairs Medical Center in Cleveland, Ohio. "There's something very personal about having a hand; most people will go to great lengths to recover one, even if it's not very functional. It's interesting that people are opting for this."
While Aszmann's approach uses a grafted muscle to relay signals from the brain to a prosthesis, others are taking a more direct route, reading brain waves directly and using them to control the hand. A team at the University of Pittsburgh, Pennsylvania, has used a brain implant to allow a paralysed woman to control a robotic arm using her thoughts alone.
Researchers working at the Department of Energy’s SLAC National Accelerator Laboratory have captured the first X-ray portraits of living bacteria. This milestone, reported in the Feb. 11 issue of Nature Communications, is a first step toward possible X-ray explorations of the molecular machinery at work in viral infections, cell division, photosynthesis and other processes that are important to biology, human health and our environment. The experiment took place at SLAC’s Linac Coherent Light Source (LCLS) X-ray laser, a DOE Office of Science User Facility.
“We have developed a unique way to rapidly explore, sort and analyze samples, with the possibility of reaching higher resolutions than other study methods,” said Janos Hajdu, a professor of biophysics at Uppsala University in Sweden, which led the research. “This could eventually be a complete game-changer.”
The experiment focused on cyanobacteria, or blue-green algae, an abundant form of bacteria that transformed Earth’s atmosphere 2.5 billion years ago by releasing breathable oxygen, making possible new forms of life that are dominant today. Cyanobacteria play a key role in the planet’s oxygen, carbon and nitrogen cycles.
Researchers sprayed living cyanobacteria in a thin stream of humid gas through a gun-like device. The cyanobacteria were alive and intact when they flew into the ultrabright, rapid-fire LCLS X-ray pulses, producing diffraction patterns recorded by detectors. The diffraction patterns preserved details of the living cyanobacteria that were compiled to reconstruct 2-D images. Researchers said it should be possible to produce 3-D images of some samples using the same technique.
The technique works with live bacteria and requires no special treatment of the samples before imaging. Other high-resolution imaging methods may require special dyes to increase the contrast in images, or work only on dead or frozen samples. The technique can capture about 100 images per second, amassing many millions of high-resolution X-ray images in a single day. This speed allows sorting and analysis of the inner structure and activity of biological particles on a massive scale, which could be arranged to show the chronological steps of a range of cellular activities.
In this way, the technique merges biology and big data, said Tomas Ekeberg, a biophysicist at Uppsala University. “You can study the full cycle of cellular processes, with each X-ray pulse providing a snapshot of the process you want to study,” he said.
It is well-known that bacteria can support each others’ growth and exchange nutrients. Scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany, and their colleagues at the universities of Jena, Kaiserslautern, and Heidelberg, however, have now discovered a new way of how bacteria can achieve this nutritional exchange. They found that some bacteria can form nanotubular structures between single cells that enable a direct exchange of nutrients.
Bacteria usually live in species-rich communities and frequently exchange nutrients and other metabolites. Until now, it was unclear whether microorganisms exchange metabolites exclusively by releasing them into the surrounding environment or whether they also use direct connections between cells for this purpose. Scientists from the Research Group Experimental Ecology and Evolution at the Max Planck Institute for Chemical Ecology in Jena, Germany addressed this question using the soil bacterium Acinetobacter baylyi and the gut microbe Escherichia coli. By experimentally deleting bacterial genes from the genome of both species, the scientists generated mutants that were no longer able to produce certain amino acids, yet produced increased amounts of others.
In co-culture, both bacterial strains were able to cross-feed each other, thereby compensating the experimentally induced deficiencies. However, separating the two bacterial strains with a filter that allowed free passage of amino acids, yet prevented a direct contact between cells, abolished growth of both strains. “This experiment showed that a direct contact between cells was required for the nutrient exchange to occur,” explains Samay Pande, who recently obtained his PhD at the Max Planck Institute in Jena on this research project and now started a postdoc at the ETH Zürich.
Observing the co-culture under the electron microscope revealed structures that formed between bacterial strains, which functioned as nanotubes and enabled the exchange of nutrients between cells. Especially remarkable, however, was the fact that only the gut microbe Escherichia coli was capable of forming these structures and connecting to Acinetobacter baylyi or other E. coli cells. “The major difference between both species is certainly that E. coli is able to actively move in liquid media, whereas A. baylyi is immotile. It may thus be possible that swimming is required for E. coli to find suitable partners and connect to them via nanotubes,” explains Christian Kost, head of the Research Group Experimental Ecology and Evolution, which is funded by the Volkswagen Foundation.
“A lack of amino acids triggered the formation of nanotubes. Deleting a gene, which is involved in the production of a certain amino acid, caused the resulting bacteria to connect to other bacterial cells and − in this way − compensate their nutritional deficiency. However, nanotubes did not form when the required amino acids were supplemented to the growth medium, indicating that the formation of these structures obviously depends on how ‘hungry’ a cell is,” the scientist summarizes the results.