segunda-feira, 17 de agosto de 2009
by: Catharine Paddock, PhD
Copyright: Medical News Today
A new US study has added to existing knowledge about the million or so brain cells in our gut by using lab mice to show that it can also grow new ones under the control of the neurotransmitter serotonin. The findings could be used to develop new drugs for gastrointestinal disorders, which affect around 25 per cent of adults in the US every day, and come second only to the common cold as the reason most Americans miss work, said the researchers.
The study, which is the first to show that the adult intestine can make new neurons in the enteric nervous system (ENS), was led by Drs Mintsai Liu, and Michael D Gershon, at Columbia University in the City of New York and is published in the 5 August issue of The Journal of Neuroscience.
Liu and Gershon and colleagues used a serotonin-related drug to add neurons to the adult enteric nervous system, which they said was the first time this had been done.
"Conceivably, treatment with compounds of this type can be used in the future to help repair a damaged or congenitally defective enteric nervous system without resorting to an invasive procedure," they told the media.
So what is the ENS?
Scientists have found evidence of what many of us already suspected: our brains and our guts "talk" to each other. In fact they are so intimately connected that some believe the gut and the brain should be viewed as part of one system.
We all know our gut is sensitive to emotions: we have "butterflies" in our stomach, we feel nauseous in certain situations, and some experiences can be "gut wrenching". These are all visceral manifestations of anxiety, anger, sadness, elation. Doctors know it is important to bear this in mind when treating gastrointestinal disorders that appear to have no obvious physical or infectious cause.
Our 30-foot long gut is embedded with cells of the enteric nervous system, the ENS, a complex system of around 100 million nerves which is often referred to as our "second brain". The ENS supervises the processes of digestion and stays in close contact with, and is heavily influenced by, the central nervous system (the CNS) which comprises the brain and spinal cord.
When the fetus grows in the womb, the ENS develops from the same tissue as the CNS, and in many respects its structure mirrors that of the brain in that it has sensory and motor neurons supported by a protective structure of glial cells which acts a bit like "scaffolding". The ENS and CNS also use many of the same chemical messengers or neurotransmitters inclusing acetylcholine and serotonin. Such communication explains obvious things like why we stop eating when we are full, or why we feel sick or lose our appetite on the morning of an important exam.
Until recently, neuroscientists believed that new neurons only grew in fetal brains and the neurons we had at birth were the ones we kept for life and that was it. But now we know that the CNS does make new neurons throughout adulthood.
And with this study, Liu and Gershon and colleagues show that under certain conditions, such as those controlled by serotonin, the ENS can also make new neurons.
It was about 4 decades ago that researchers discovered that our bowels contain high levels of serotonin 5-HT. In fact a recently developed drug, tegaserod, designed to treat constipation and irritable bowel syndrome targets the serotonin receptor 5-HT4. However, the drug, which received approval from the US Food and Drug Administration in 2002, was later withdrawn because it was thought it might cause heart attacks.
Liu and Gershon and colleagues found that the 5-HT4 receptor and, by inference, serotonin, are intimately involved in controlling the production of new ENS neurons after birth.
They compared mice that had the 5-HT4 receptor ("normal" mice) with mice that did not. Compared with the normal mice, the mice that lacked the receptor had the same number of neurons at birth, but they waned as the mice got older.
Also, when the researchers gave the normal mice a drug that stimulated the 5-HT4 receptor, they found not only that it enhanced the post-birth production of ENS neurons but it protected the ones that were already there.
Dr Arturo Alvarez-Buylla of the University of California, San Francisco, an expert in stem-cell neurobiology and developmental neuroscience who was not involved with the study, said that Liu and Gershon and colleagues had helped to clarify some unanswered questions about the gastrointestinal system. He said their finding:
"Not only suggests that new enteric neurons can be generated in the adult, but that activation of the serotonin receptor is required for this process."
"The enteric nervous system has a very large number of neurons, yet we know very little about their progressive loss during life and whether they can be regenerated," he added.
The research was funded by the National Institutes of Health and Novartis, the drug company that makes tegaserod.
by Carol Posted
in Mental Health
It’s not surprising that our emotions affect our health. The “Type A” personality and its relationship to heart disease was identified fifty years ago, While the research in this area has been refined, what it has found is that the hostility aspect of Type A personalities is what is associated with heart disease. In other words, a strong negative emotion has been shown to be connected with a physical disease.
In contrast, laughter actually helps your cardiovascular system in part by reducing stress hormones and also by causing your body to relax.
Now that we know this, what do we do? One thing is that when we feel stress, we need to make a conscious decision to do something different. Of course, it would not be appropriate to break out a romantic comedy during a stressful business meeting. But it would be a great idea to distract your mind with it after work that evening. The only thing worse than a stressful period of time at work is rehashing those events over and over in your mind after work is supposed to be done.
Yet when we are stressed out, making a choice to watch a funny movie is going to feel strange. What feels natural when we are stressed is to deal directly with the stress. Yet sometimes that is not possible. You cannot change past events and brooding over them is actually not helpful. If you can get your mind into a different frame of reference, you actually might become more effective at solving problems. So, even though it feels weird and you are not in the mood for a movie, start it up anyway. Or do something else that makes you laugh. Wad up a piece of aluminum foil and watch your cat play with it. Watch dumb videos on line. Find a website or a book with a lot of jokes and read.
Why does this work? Why is it not avoiding a problem?
Stress is ultimately caused by things we cannot control. You are on your way to work and there is a wreck up ahead. The highway is a parking lot. You are going to be late. You can’t get off; you can only sit there. For many people, this lack of control would be close to intolerable, which explains the level of road rage around us. Sitting in traffic, these folks get madder and madder, when anger actually gets in the way of problem solving.
The alternative in this situation would be to anticipate this kind of problem. When traffic gets stopped, pull out the cell phone and tell folks what is going on so they know that you are on your way and are unavoidably delayed. Then put in a CD of a comedy show or whatever else you like to listen to. Enjoy yourself because there’s nothing else you can do. When traffic clears up, get yourself to work.
Ultimately, when we are aware of the limitations of our ability to control a situation and when we choose not to take responsibility for more than the what we really can control, we can actually reduce stress. When you have done what you can to address a situation, it becomes time to help your brain shift gears from frustration to relaxation. If you do this, your heart will appreciate it.
Contact: Barb Abney
University of Central Florida
Cleaner wound healing, preventing spread of tumors among potential long-term implications
University of Central Florida researchers have shown for the first time that light energy can gently guide and change the orientation of living cells within lab cultures. That ability to optically steer cells could be a major step in harnessing the healing power of stem cells and guiding them to areas of the body that need help.
The results, presented at the 2009 Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, were discovered by a research team led by Aristide Dogariu, an optical scientist at the College of Optics and Photonics, and Kiminobu Sugaya, a stem cell researcher at the College of Medicine's Burnett School of Biomedical Sciences.
Long-term implications of the work include stimulating and controlling tissue regeneration for cleaner wound healing and the possibility of altering the shapes of cells and preventing malignant tumors from spreading throughout the body.
While optical techniques such as drilling microscopic holes with light or using the light as tweezers have shown promise in manipulating small pieces of matter, the UCF team explored the use of a gentler light energy. Their work showed for the first time that optically induced torques can affect components within cells that drive their motility -- their ability to move spontaneously -- and change the orientation of cells within cultures.
While earlier studies of cell manipulation have emphasized shielding the cell from the power of the light, Dogariu and Sugaya focused on using that energy to stimulate the cells' natural tendencies.
Living cells use energy to move actively and spontaneously. To influence them without jeopardizing their chemical makeup was a tremendous challenge. Dogariu and Sugaya began exploring the idea of moving an entire cell by focusing on its inner mechanisms. Inside the cells there are slender rods made up of a protein called actin.
"Actin rods are constantly vibrating, causing the cells to move sporadically" Sugaya said. The researchers demonstrated that low-intensity polarized light can guide the rods' Brownian motion to ever-so-slowly line up and move in the desired direction.
"Stronger light would simply kill them," Dogariu said. "We wanted to gently help the cells do their job the way they know how to do it."
A time-lapse video shows that after more than two hours of exposure to light with specific characteristics, a group of stem cells migrates from a seemingly random mix of shapes, movement and sizes to a uniform lineup.
UCF Stands For Opportunity: The University of Central Florida is a metropolitan research university that ranks as the 5th largest in the nation with more than 50,000 students. UCF's first classes were offered in 1968. The university offers impressive academic and research environments that power the region's economic development. UCF's culture of opportunity is driven by our diversity, Orlando environment, history of entrepreneurship and our youth, relevance and energy. For more information, visit http://news.ucf.edu.
By Leonardo Vintiñi
Epoch Times Staff
“In the six hundredth year of Noah's life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened. And the rain was upon the earth forty days and forty nights.” —Genesis 7:11-12
Approximately 9,000 to 5,000 years ago in the northern Turkish province of Sinop, an event of spectacular historic magnitude took place. So spectacular, in fact, that some believe it represents proof that the “Great Flood” recounted in the Bible may have been an actual (though somewhat exaggerated) representation of real events.
In September of 2004, an expedition in the Black Sea by a team of scientists from various institutions (including the National Geographic Society) determined that the sea in question was not always as we know it today.
They concluded that it had originated from an immense lake of black water that at one point in history began to widen in an unusually rapid way. The change was so great, in fact, that inhabitants of the surrounding area were immediately obliged to search for more secure land, hastily leaving behind housing, tools, and other traces of their former lives.
This led the underwater expedition headed by oceanographer Robert Ballad to declare that there once existed human settlements that now reside more than 300 feet underwater. This startling Black Sea discovery not only contributed to a thoroughly enriched historical understanding of the serious alterations in water level suffered in the ancient Middle East, but also raised questions about what caused the alteration in the first place.
Since then, scientists and reporters continue to probe the unresolved issue; it is a key to understanding the historical development of human civilization and the different climatic stages that Earth has experienced. Furthermore, it is an important theme intertwined not only with the Judeo-Christian tradition but with many legends from different cultures around the world—the Great Flood.
The Black Sea: Proof of the Flood?
Contemporary hypotheses suggesting that the rapid growth of the Black Sea was a consequence of an incredible rainfall of planetary proportions has never received great sale. Based on a large framework of scientific laws, predominantly geological, which have been established on the basis of empirical observation over the years, makes this a rather improbable scenario.
In the first place, skeptical geologists propose that for such a flood to have occurred, we would find a similar stratum throughout the world covered with pebbles, sludge, boulders, and other elements. It is curious that this layer cannot be found, even more so when the flood narrated by the Bible had taken place in a time as recent as 3000 B.C.
Neither can be found the strata of fossils, with different animal and vegetable species occupying specific soil layers. According to flood logic, the animal remains of all species before the big flood (including the extinct dinosaurs) should be found today in only one stratum, without any distinction. But paleontology completely contradicts these suppositions.
Yet these examples appear to be only the tip of the iceberg comprising the arguments that refute a global flood. Even so, much of such reasoning is refuted with equal grace by the “pro-flood” scientists. In fact, descriptions like “all the sources of the great abyss were broken” or “the waterfalls of the heavens were opened” recounted in Genesis are backed up by hypotheses that, although incredible, are impossible to rule out as being incompatible with reality.
One of the more dramatic hypotheses proposed that the planet could have been covered with water up to its highest points, contrary to the calculations indicating that all the water suspended in the atmosphere would only be enough to reach a modest 1.2 inches over the total surface of Earth.
These “flood supporters” calculate that if the geography of Earth went through a leveling out in its surface—the mountains being lowered, the sea troughs being elevated—then the entire Earth would be covered by thousands of feet of water.
According to the water-covers-the-earth theory, in the times of Noah the upper layers of the atmosphere contained a substantial amount of water that today makes up the oceans. This atmospheric water was what covered the whole planet, and which later returned to the ocean troughs by violent vertical tectonic movements. Researchers in support of this idea believe it makes suitable reference to the “waterfalls of the heavens” that could condense themselves thanks to dust generated by several simultaneous volcanic eruptions.
With respect to non-Biblical myths about a purifying flood, these can be found in the Hindu, Sumerian, Greek, Acadia, Chinese, Mapuche, Mayan, Aztec, and Pascuanese (Easter Island) cultures, among others. Several of these stories appear to possess surprisingly similar common factors. Among the most repeated themes are those of celestial announcements ignored by the people, the great flood itself, the construction of an ark to preserve life from the flood, and the later restoration of life on the planet.
A clear example of this similarity is provided by pre-Biblical Mesopotamian history of the flood in which the god “Ea” warned Uta-na-pistim, king of Shuruppak, about the punishment that awaits humanity for its serious moral degeneration. Uta-na-pistim received instructions from the god to construct a craft in the form of a cube with eight floors, and said that it should include in it a pair of each species of animal, plant seeds, as well as his own family. Thus, Uta-na-pistim survived the several-day-long deluge, released a bird to verify the proximity of dry land, and made an animal sacrifice to the gods.
In Search of the Lost Ark
One separate point that adds weight to the Bible controversy is the body of photographic and physical evidence of a large object encrusted in Mount Ararat, where, according to the Christian text narrations, finally rested the ark of Noah.
In the beginning of 2006, University of Richmond professor Porcher Taylor declared that according to an extensive study made over years of satellite photography there is a foreign object encrusted in the area northeast of the mountain, the length of which coincides perfectly with that of the ark recounted in the Bible.
Such satellite images from above Ararat have inspired the curiosity of a great number of scientists since this declaration was made in 1974. Several expeditions of investigators also managed to rescue remains of petrified wood, as well as 13 strong anchors of rock in the area surrounding the supposed location of the possible archeological treasure. Ultrasonic tests have also been made, revealing a very odd structure embedded in the rock.
In spite of the multiplicity of texts from diverse cultures which tell the story of a great ancient flood, the magnitude and duration of such an event seems to be a point of argument, even among those who believe that such an event actually occurred. Thus, while a small number of researchers suggests that this flood covered the entire Earth in vast amounts of water, most geologists agree that such a scenario is an impossibility.
While not everyone believes ancient accounts that describe the re-creation of humanity from the salvation of a handful of people, it would seem that a climatic catastrophe actually did take place across the entire planet several millennia ago. We can also safely assume that an indefinite number of human beings in elevated locations had the capacity to continue civilization, and to transmit the story of the occurrence to later generations.
Up until the time when evidence is revealed to definitively tip the scales toward one of these particular theories, the story of a time when a great flood purged the sins of man will be taken as a myth for some and a statement of historical fact for others. Either way, this great ancient flood remains forever a part of the story of humankind.
sábado, 15 de agosto de 2009
The hemp plant is one of six identified by Department of Primary Industries (DPI) scientists in Queensland as a source of natural resin to reduce the building industry's reliance on resins produced from fossil fuels.
DPI project officer Dr Andries Potgieter said generating resins from renewable sources such as plant oils could reduce greenhouse gas emissions and result in a smaller carbon footprint.
Currently most resins and adhesives used in aerospace structures and in structural building materials are ultimately derived from crude oil.
Cannabis sativa, also known as marihuana or hemp, was very widely used in the past.
James Cook's Endeavour and ships of its era had all their sails and ropes made of hemp.
Industrial varieties, which have a negligible content of the active ingredient tetra hydra cannabinol (THC), are grown under licence in Queensland.
"The first step in the project was identifying which of the plant oil species are best suited to the Australian environment,'' Dr Potgieter said.
"Initially, we tested 13 plants for their suitability to Australian agronomic conditions and unsaturated oil content.
"We were able to narrow the selection down to eight species straight away due to the classification of some as weeds and their limited exposure to the Australian broad-acre cropping environment.
"We now have a final list of six plant species that show high potential for the extraction of oil for resin, and are currently not part of an existing oil production and refinery system.''
Research will continue into the suitability of hemp; Calendula officinalis (pot marigold), Camelina sativa (false flax); Pongamia pinnata (pongam tree); Lesquerella fendleri (desert mustard); and Crambe abyssinica (abyssinan mustard).
The joint project between DPI, the University of Southern Queensland and Loc Composites could to lead to the production of fibre composites which can be used in sustainable high technology building products used in, for example, the production of railway sleepers and small bridges, Dr Potgieter said.
The main challenge is to make it financially viable for farmers to grow crops for this purpose.
by Jo Marchant
Uniform lighting conditions appear rough and almost unnatural
(Image: Alexandrino Goncalves)
From cave paintings to Roman mosaics, our perception of archaeological artefacts is affected by how they are lit - which is usually by bright modern lights. As a result, the way we see them may bear little resemblance to how they would have looked to the people who created them.
Alan Chalmers of the Digital Laboratory at the University of Warwick, UK, wants to fix that. He is working with computer scientists and archaeologists at the Roman site of Conimbriga in Portugal to come up with computer reconstructions that take account of the lighting conditions of the time. "We want a research tool, not just a pretty picture," he says.
Conimbriga was known for its splendid House of Fountains, and many of the mosaics and frescoes at this richly decorated villa are still intact. These include a hunting scene on the floor of the sala da caçada or hunting room.
Most computer reconstructions of the way archaeological sites would have looked assume uniform lighting conditions, and even when given this treatment, the sala da caçada looks impressive enough. But as Chalmers points out, the room would have normally have been lit by a series of lamps or lucernas that burned olive oil, which would give it a quite different look.
Computer science students at the Polytechnic Institute of Leiria and the University of Trás-os-Montes and Alto Douro in Portugal, supervised by Chalmers, recreated a Roman-style lucerna and measured the properties of its light. They then used rendering software to model how the room would look when lit by such lamps (ACM Journal on Computing and Cultural Heritage, DOI: 10.1145/1551676.1551679).
The result is a warm, sumptuous glow, which the researchers describe as subtle and pleasant compared with the "rough, almost unnatural" effect of modern lighting (see images). As well as giving us more authentic images, the technique could help answer questions such as how many lamps it would have taken to light a room.
This could answer questions such as how many lamps it would have taken to light a room
Chalmers has tested the approach at other archaeological sites, with intriguing results. Simulations from Cap Blanc, a 15,000-year-old cave site in France, hint that the prehistoric inhabitants who carved wild beasts into the cave wall may have deliberately left the legs blurred to enhance the effect of movement in the light of a flickering flame.
Archaeologist Duncan Brown of the Art and Heritage department of Southampton City Council in the UK, who has worked with Chalmers, says the approach adds a new dimension to his work. "It gives you a better understanding," he says. "You can model any space you want, but unless you model the light authentically, you won't see it the same way as the people who lived there."
terça-feira, 11 de agosto de 2009
They use this intelligence to intentionally deceive their fellow dogs and people to earn their treats, canine researcher Stanley Coren said.
"Their stunning flashes of brilliance and creativity are reminders that they may not be Einsteins but are sure closer to humans than we thought," the researcher from the University of British Columbia in Canada said at the 117th annual convention of American Psychological Association in Toronto yesterday.
According to several behavioural measures, dogs' mental abilities are close to human child aged between 2-2.5 years, can count up to five and spot errors in computations.
The intelligence of canines is dependent on various factors including their breed, environment around them and training imparted by their handlers, he said.
"Border Collies are number one; poodles are second followed by German Shephards. Fourth on the list is Golden Retrievers; fifth Doberman; sixth Shetland Sheepdogs and finally Labrador retrievers," the canine scientist said.
More Stories from this section
by Katie Silver
Quantum computers harness the power of quantum physics where, "strange things can happen," said lead author of the study, Tom Stace at the University of Queensland (UQ) in Brisbane, Australia.
Working on the principle that electrons can be in multiple places at the same time, quantum computers can operate beyond the binary capabilities of ordinary computers. That is they can encode both a '0' and a '1' at the same time, making a third 'superposition' – a concept that is not at all intuitive.
Risk of information loss
These parts or qubits, are tiny particles kept at very cold temperatures and can be a single atom or a photon. Quantum computers can operate in parallel when completing calculations, giving them far greater power than their sequentially processing counterparts.
"If we can take advantage of this phenomena, we can do certain computational tasks that on a regular computer would either be impossible or take so long so as not to be practical," said Stace.
Whilst providing more scope than an ordinary computer, a quantum computer is also at far greater risk of errors and information loss. This is because the world at the atomic level is so sensitive, that qubits can easily be lost or suffer a 'bitslip', whereby they are accidentally zapped to the opposite state.
To get a handle on how serious this problem could be for the future development of quantum computers, Stace along with Andrew Doherty, also at UQ, and Sean Barret at Macquarie University in Sydney, created a complex mathematical model to test what happens when losses or errors happen within the quantum information.
Powerful encryption systems
The study, published in the Physical Review Letters suggests that quantum computers are still able to function normally even when 10% of the information has errors, or up to 50% of the qubits are missing.
One of the major implications of the finding, said the authors, is that both errors and losses can coexist at the same time. Previously, theory suggested that either errors or losses would need to be exclusive, so as not to disrupt the system.
This is the first study to "rigorously prove" that "quantum error correction for loss is possible, just like in classical machines," said David Reilly, a physicist from the University of Sydney, who was not involved in the research. "Now we only have to get to a certain level of [accuracy]… because we know quantum correction will take care of the errors," he said.
Researchers hope that quantum computers could one day make very powerful encryption systems, but they will also have applications ranging from long distance communications networks to machines capable of modelling very complex systems.
by Ed Edelson
The finding comes from the Women's Health Initiative, which has tracked more than 97,000 postmenopausal American women for more than eight years.
"In addition to looking at hormones and their effect on heart disease and cancer, the study also examined psychosocial and social factors and how they affected the health of postmenopausal women," said Dr. Hilary A. Tindle, an assistant professor of medicine at the University of Pittsburgh, and lead author of a report in the Aug. 10 issue of Circulation. "Fortunately, we have this wealth of information on the psychological profile at the time they joined the study."
Read the full story at: http://www.healthday.com
by Ewen Callaway
Meat-eating – and diseases that come with it – have a long history among our ancestors, suggests a new study of an ancient hominin skeleton.
The analysis of 1.5 to 2.8 million-year-old vertebrae of Australopithecus africanus recovered in South Africa reveals signs of a bacterial infection that is normally contracted from eating meat or dairy foods.
"This is the most ancient case of an infectious disease in a hominin," says Ruggero D'Anastasio, a palaeoanthropologist at State University "Gabriele d'Annunzio" in Chieti, Italy, who diagnosed the skeleton with a disease called brucellosis.
Read ful story at: http://www.newscientist.com
By Jason Palmer
Science and technology reporter
A computer with DNA as its information carrier can solve classic logic conundrums, researchers say.
DNA has been used to do simple number crunching before, but a system developed by Israeli scientists can effectively answer yes or no questions.
Strands of DNA are designed to give off a green light corresponding to "yes".
In Nature Nanotechnology, the team also describes a program which bridges the gap between a computer programming language and DNA computing code.
The team, led by Tom Ran and Ehud Shapiro of the Weizmann Institute in Israel, has been developing DNA-based computation systems for a number of years, including "computers" that can diagnose and treat cancers autonomously.
But the current approach is fundamentally different, Professor Shapiro told BBC News.
"Using more sophisticated biochemistry, we were able to implement simple logic programs, which are more akin to the way people program electronic computers," he said.
The system devised by the researchers uses molecules to represent facts and rules. In this way, the team was able to use it to answer simple molecular "questions".
First, they tried the system with simple "if… then…" propositions. One of these went as follows: "All men are mortal. Socrates is a man. Therefore, Socrates is mortal."
When fed a molecular rule (all men are mortal) and a molecular fact (Socrates is a man), the DNA computing system was able to answer the question "Is Socrates mortal?" correctly.
The team went on to set up more complicated queries involving multiple rules and facts. The DNA devices were able to deduce the correct answers every time.
The answer was encoded in a flash of green light. Some of the DNA strands were equipped with a naturally glowing fluorescent molecule bound to a second molecule which keeps the light covered.
A specialised enzyme, attracted to the part of the molecule representing the correct answer, would then remove this cover to let the light shine.
Professor Shapiro said the fact this system was based on clever biochemistry meant it was no less a computer than the conventional kind.
"Of course when the examples are simple, as in today's logic program, one can pre-compute the answer with pencil and paper. But in principle there is no difference between simple and complex computer programs; they can compute only what they programmed to compute.
"It is important to note that, while bio-molecular computing trails behind electronic computing - in terms of actual computing power, maturity of the technology, and sheer historical progression - at the conceptual level they stand side-by-side, without one being a more 'preferred' embodiment of the ideas of computation," he said.
To save time and effort, the researchers developed a robotic system to set up the DNA-based propositions and queries.
The system can take in facts and rules as a computer file of simple text. The robotic "compiler" can then turn those facts and rules into the DNA starting products of a logical query.
"We had to do many, many experiments to develop, debug, and calibrate the molecular computing system, and without computer robotic support to this process, we would not have finished this in our lifetime," Professor Shapiro said.
While the current work may raise the bar for programmable, molecular computing, Professor Shapiro said: "the ultimate applications are in programmable autonomous computing devices that can operate in a biological environment."
In other words, computers that go to work inside a cell.
segunda-feira, 10 de agosto de 2009
In 1953, Stanley Miller filled two flasks with chemicals assumed to be present on the primitive Earth, connected the flasks with rubber tubes and introduced some electrical sparks as a stand-in for lightning. The now famous experiment showed what amino acids, the building blocks of proteins, could easily be generated from this primordial stew. But despite that seminal experiment, neither he nor others were able to take the next step: that of showing how life’s code could come from such humble beginnings.
By working with the simplest amino acids and elementary RNAs, physicists led by Rockefeller University’s Albert J. Libchaber, head of the Laboratory of Experimental Condensed Matter Physics, have now generated the first theoretical model that shows how a coded genetic system can emerge from an ancestral broth of simple molecules. “All these molecules have different properties and these properties define their interactions,” says first author Jean Lehmann, whose work appears in the June issue of PloS One. “What are the constraints that allow these molecules to self-organize into a code? We can play with that.”
The genetic code is a triplet code such that every triplet sequence of letters on messenger RNA (mRNA) corresponds to one of the 20 amino acids that make up proteins. Molecular adaptors called transfer RNAs (tRNAs) then convert this information into proteins that can achieve some specific tasks in the organism. Let’s say that each triplet sequence on mRNA, known as a codon, represents an outlet that can only accept a tRNA with a complementary anticodon. Translation works because each codon-anticodon match corresponds with an amino acid. As each tRNA is plugged in, a chain of amino acids is formed in the same order as the codons until translation is complete.
However, primitive tRNAs were not as finicky as tRNAs are today and could load any amino acid known to exist during the time of prebiotic Earth. Without the ability of tRNA to discriminate between various amino acids, such a random system might not be able to self-assemble into a highly organized code capable of supporting life.
At these concentrations, the scientists found that a vetting process began to unfold whereby the tRNA and the amino acid began to seek each other out. All in all, an elementary translation process depended on two time scales: the time during which a tRNA remains bound to its codon (hybridization) and the time it takes for the amino acid on that tRNA to form a new chemical bond with the amino acid next to it (polymerization).
“It takes a lifetime for the tRNA to dissociate from its codon,” says Libchaber, who is also Detlev W. Bronk Professor at Rockefeller. “If it takes the amino acid loaded on the RNA longer than a lifetime to polymerize to an amino acid nearby, the selection of tRNA and amino acid doesn’t occur. But when the two lifetimes are comparable, even when there is nonspecific loading of an amino acid, a selection process begins to take hold because some amino acids would be more adaptive during that time span -- and start what would be the beginning of a code.”
Although Libchaber and Lehmann point out that the analysis certainly does not provide a full picture of the problem, the work nonetheless brings us one step closer to understanding how Life first began. “The dream of physicists is to create elementary life,” Libchaber says. “Then we would know that we understand something.”
Provided by Rockefeller University
sábado, 8 de agosto de 2009
By Fiona Govan
Archaeologists have discovered what they believe is man's earliest map, dating from almost 14,000 years ago
A stone tablet found in a cave in Abauntz in the Navarra region of northern Spain is believed to contain the earliest known representation of a landscape.
Engravings on the stone, which measures less than seven inches by five inches, and is less than an inch thick, appear to depict mountains, meandering rivers and areas of good foraging and hunting.
A team from the University of Zaragoza spent 15 years deciphering the etched lines and squiggles after unearthing the artefact during excavation of the cave in 1993.
"We can say with certainty that it is a sketch, a map of the surrounding area," said Pilar Utrilla, who led the research team.
"Whoever made it sought to capture in stone the flow of the watercourses, the mountains outside the cave and the animals found in the area."
"The landscape depicted corresponds exactly to the surrounding geography," she said. "Complete with herds of ibex marked on one of the mountains visible from the cave itself."
The research, which is published in the latest edition of the Journal of Human Evolution, furthers understanding of early modern human capacities of spatial awareness, planning and organised hunting.
"We can't be sure what was intended in the making of the tablet but it was clearly important to those who populated the cave 13,660 years ago," said Ms Utrilla. "Maybe it was to record areas rich in mushrooms, birds' eggs, or flint used for making tools."
The researchers believe it may also have been used as a storytelling device or to plan a hunting expedition.
"Nothing like this has been discovered elsewhere in western Europe," she said.
By Charlie Sorrel
£400 million ($668 million) will be spend on installing and monitoring CCTV cameras in the homes of private citizens. Why? To make sure the kids are doing their homework, going to bed early and eating their vegetables. The scheme has, astonishingly, already been running in 2,000 family homes. The government’s “children’s secretary” Ed Balls is behind the plan, which is aimed at problem, antisocial families. The idea is that, if a child has a more stable home life, he or she will be less likely to stray into crime and drugs.
It gets worse. The government is also maintaining a private army, incredibly not called “Thought Police”, which will “be sent round to carry out home checks,” according to the Sunday Express. And in a scheme which firmly cements the nation’s reputation as a “nanny state”, the kids and their families will be forced to sign “behavior contracts” which will “set out parents’ duties to ensure children behave and do their homework.”
And remember, this is the left-wing government. The Shadow Home Secretary Chris Grayling, batting for the conservatives, thinks these plans are “too little, and too late,” implying that even more obtrusive work needs to be done. Rumors that a new detention center, named Room 101, is being constructed inside the Ministry of Love are unconfirmed.
UPDATE: Further research shows that the Express didn’t quite have all its facts straight. This scheme is active, and the numbers are fairly accurate (if estimated), but the mentions of actual cameras in people’s homes are exaggerated. The truth is that the scheme can take the most troublesome families out of their homes and move them, temporarily, to a neutral, government-run compound. Here they will be under 24-hour supervision. CCTV cameras are not specifically mentioned, not are they denied, but 24-hour “supervision” certainly doesn’t rule this out from the camera-loving Brits.
It remains, though, that this is still excessively intrusive into the private lives of citizens, cameras or not. I have added links to the source and also more reliable reports. Thanks to everyone who wrote in.
- Sin Bins for Worst Families [Sunday Express. Thanks, Annaliza]
- Government calls for tough family intervention to prevent youth crime [Home Office]
- Sadly not from the Onion [Metafilter]
- Family Intervention [Home Office/Respect.gov]
quarta-feira, 5 de agosto de 2009
By Charles Q. Choi
The first artificial organelle may help lead to safer heparin production and, someday, entire artificial cells
The Golgi apparatus is an organelle, akin to a miniature organ in a cell, made up of a network of sacs piled together like a stack of pancakes. The role it plays in chemically modifying proteins is crucial for their stability and function, and it also helps manufacture complex sugars. However, the Golgi apparatus remains one of the most poorly understood organelles in the body.
"The sacs are fluid and constantly change shape, so it's difficult to get a handle on," explains researcher Robert Linhardt, a chemist at Rensselaer Polytechnic Institute. "And while we know the general direction of the flow of vesicles between stacks, we don't really know what cargoes they're carrying."
To better dissect how the Golgi apparatus works, Linhardt and his colleagues tried creating a synthetic version of it, designing a square-millimeter-sized lab-on-a-chip to mimic the assembly line of enzymes within the Golgi apparatus that modify a biomolecule. The sample molecules are attached to magnetic particles, suspended in a watery droplet 300-billionths of a liter in size and placed on the chip. When the desired location on the chip for those molecules is electrically charged, it becomes more attractive to water, causing the droplet to flow there. A larger magnet can then be kept under that spot to keep the magnetic particles attached to the biomolecules in place. In this way, the drop can be moved through chambers loaded with an assembly line of enzymes, as well as sugars and other raw materials the enzymes might attach to the sample.
In experiments with an inactive precursor of heparin, a widely used blood thinner, the scientists found their device could quickly and efficiently modify the anticoagulant to make it functional, findings they are scheduled to detail in the August 12 issue of the Journal of the American Chemical Society. The researchers suggest that an artificial Golgi could lead to a faster, safer method of producing heparin than current techniques, which employ animal tissue.
This device is apparently the first instance of an artificial organelle, says biochemist and glycobiologist Jerry Turnbull of the University of Liverpool in England, who did not participate in this study. Although the proof-of-concept system Linhardt demonstrated is simple, employing just one enzyme, it "clearly has potential to be greatly diversified as a tool," he adds.
Scientists have experimented with building cells up piece by piece for decades, including the creation of simple artificial cells in the form of bubbles made of synthetic cell membranes, to better understand how life on Earth might have began. Then, in 1997, scientists devised the first artificial human chromosome. And earlier this year, molecular technologist George Church of Harvard University and his colleagues reported a breakthrough in developing artificial ribosomes, bodies inside each cell that make proteins based on instructions from DNA. Although the first artificial ribosome was created in 1968, this recent work assembled ribosomes in the kind of environment where protein synthesis normally occurs, unlike before. Such ribosomes could be inexpensive cell-independent alternatives to current industrial processes that manufacture proteins using cells, Church says.
Now that Linhardt and his colleagues have devised a primitive artificial Golgi, in the future they plan on creating a synthetic endoplasmic reticulum (ER) as well, the organelle into which ribosomes are studded, where protein synthesis and folding take place.
"We'd even like to integrate an artificial Golgi and ER together," Linhardt says. "We're basically taking pieces of a cell and making them on electronic chips, and hopefully moving on to even more complex systems. Of course, organelles are pretty complicated, with the mitochondria and chloroplasts almost having the complexity of a bacterial cell, so there's a lot of work to go."
In the near term, the artificial Golgi could help scientists understand how the actual organelle modifies biomolecules—for instance, how it glycosylates or adds sugars to proteins. The sugars on a protein can affect its structure and function, how the immune system reacts to it and how long it remains in the bloodstream.
"Over half of all proteins are glycosylated, so it's clear that it's an important process, but we just don't have good ways of studying it in the cell," Linhardt says. "This platform gives us an artificial system to test it with, see what's important."
for the efficient and cheap storage
of the sun’s energy
A Utah-based company has found a new way to store solar energy – in a small ceramic disk which can store more power for less. Researchers at Ceramatec have created the disk, which can hold up to 20-kilowatt hours, enough to power an entire house for a large portion of the day.
The new battery runs on sodium-sulfur — a composition that typically operates at greater than 600°F. “Sodium-sulfur is more energetic than lead-acid, so if you can somehow get it to a lower temperature, it would be valuable for residential use”, Ralph Brodd, an independent energy conversion consultant, says.
Ceramatec’s new battery runs at less than 200°F. The secret is a thin ceramic membrane that is sandwiched between the sodium and sulfur. Only positive sodium ions can pass through, leaving electrons to create a useful electrical current.
Ceramatec says that batteries will be ready for market testing in 2011, and will sell for about $2000. The disk has not yet been manufactured for residential use, but the creators have spoken optimistically about the possibility.
The convergence of two key technologies — solar power and deep-storage batteries — has profound implications for oil-strapped the US.
“These batteries switch the whole dialogue to renewables,” said Daniel Nocera, professor of energy at the Massachusetts Institute of Technology who sits on Ceramatec’s advisory board. “They will turn us away from dumb technology, circa 1900 — a 110-year-old approach — and turn us forward.”
More Stories from this section
by Patricia Lantz
The Nebra Star disc, bronze, thirty centimeters in length and covered with golden decorations that form a picture of the sun, the moon and stars, is rewriting the epic story of how civilization came to Europe, over 3000 year ago. Archaeologists believe that the Nebra Star disc dates all the way back to 1600 BC, making it the oldest accurate picture of the night sky in all history.
The images on the star disc have sacred meaning. The Sun is a bringer of life, while the Moon symbolizes the passage of time. The small cluster of seven stars between the sun and the moon on the star disc resembled the constellation known the Pleiades. The horizon band marks the Sun’s sacred solstices in Central Europe. All these symbols represent the complexity of European belief systems.
Watch “Secrets of the Star Disc” Sunday, August 2, on National Geographic (Read more)
by Hannah Hickey
The team led by a University of Washington researcher has used computers to extract patterns in ancient Indus symbols. The study, published this week in the Proceedings of the National Academy of Sciences, shows distinct patterns in the symbols' placement in sequences and creates a statistical model for the unknown language.
"The statistical model provides insights into the underlying grammatical structure of the Indus script," said lead author Rajesh Rao, a UW associate professor of computer science. "Such a model can be valuable for decipherment, because any meaning ascribed to a symbol must make sense in the context of other symbols that precede or follow it."
Co-authors are Nisha Yadav and Mayank Vahia of the Tata Institute of Fundamental Research and Centre for Excellence in Basic Sciences in Mumbai; Hrishikesh Joglekar of Mumbai; R. Adhikari of the Institute of Mathematical Sciences in Chennai; and Iravatham Mahadevan of the Indus Research Centre in Chennai.
Despite dozens of attempts, nobody has yet deciphered the Indus script. The symbols are found on tiny seals, tablets and amulets, left by people inhabiting the Indus Valley from about 2600 to 1900 B.C. Each artifact is inscribed with a sequence that is typically five to six symbols long.
Some people have questioned whether the symbols represent a language at all, or are merely pictograms of political or religious icons.
The new study looks for mathematical patterns in the sequence of symbols. Calculations show that the order of symbols is meaningful; taking one symbol from a sequence found on an artifact and changing its position produces a new sequence that has a much lower probability of belonging to the hypothetical language. The authors said the presence of such distinct rules for sequencing symbols provides further support for the group's previous findings, reported earlier this year in the journal Science, that the unknown script might represent a language.
"These results give us confidence that there is a clear underlying logic in Indus writing," Vahia said.
Seals with sequences of Indus symbols have been found as far away as West Asia, in the region historically known as Mesopotamia and site of modern-day Iraq. The statistical results showed that the West-Asian sequences are ordered differently from sequences on artifacts found in the Indus valley. This supports earlier theories that the script may have been used by Indus traders in West Asia to represent different information compared to the Indus region.
"The finding that the Indus script may have been versatile enough to represent different subject matter in West Asia is provocative. This finding is hard to reconcile with the claim that the script merely represents religious or political symbols," Rao said.
The researchers used a Markov model, a statistical method that estimates the likelihood of a future event (such as inscribing a particular symbol) based on patterns seen in the past. The method was first developed by Russian mathematician Andrey Markov a century ago and is increasingly used in economics, genetics, speech-recognition and other fields.
"One of the main purposes of our paper is to introduce Markov models, and statistical models in general, as computational tools for investigating ancient scripts," Adhikari said.
One application described in the paper uses the statistical model to fill in missing symbols on damaged archaeological artifacts. Such filled-in texts can increase the pool of data available for deciphering the writings of ancient civilizations, Rao said.
The research was funded by the Packard Foundation, the Sir Jamsetji Tata Trust, the University of Washington and the Indus Research Centre.
For more information, contact Rao at email@example.com. He is currently traveling in India and is best reached by e-mail.