Geo-Neutrinos: Discovery of Subatomic Particles Could Answer Deep Questions in Geology

The finding, made by the Borexino Collaboration at the Gran Sasso National Laboratory of the Italian Institute of Nuclear Physics, was reported in a paper published in the April issue of Physics Letters B. The work builds on earlier evidence of so-called "geo-neutrinos" obtained during a Japanese experiment in 2005.

"This is an important result," said Frank Calaprice, a professor of physics at Princeton and one of the study's authors. "It shows that geo-neutrinos have been detected and firmly establishes a new tool to study the interior of Earth."

Neutrinos, which are chargeless, inert, fundamental particles, are emitted by the sun and cosmic rays entering Earth's atmosphere. Geo-neutrinos are antineutrinos -- neutrinos' antimatter counterparts. Geo-neutrinos originate from the radioactive decay of uranium, thorium and potassium in Earth's crust and mantle -- the thick layer extending to 1,800 miles below the surface.

At laboratories like Gran Sasso, researchers are using instruments that act as geo-neutrino "telescopes," looking into Earth's interior by detecting these curious particles.

Scientists expect that geo-neutrinos will aid them in better identifying what constitutes matter deep within Earth. "It's a very significant discovery and holds much promise for better understanding the composition of Earth and how Earth operates," said Thomas Duffy, a professor of geosciences at Princeton, who was not involved in the research.

Earth scientists would like to know more about the crucial role that decaying elements such as uranium and thorium play in heating up Earth and causing convection in its mantle -- the slow, steady flow of hot rock in the interior carrying heat from great depths to Earth's surface. Convection, in turn, drives plate tectonics and all the accompanying dynamics of geology seen from the surface -- continents moving, seafloor spreading, volcanoes erupting and earthquakes occurring. No one knows whether radioactive decay dominates the heating action or is just a player among many factors.

The origin of the power produced within Earth is one of the fundamental questions of geology, according to Calaprice. The definite detection of geo-neutrinos by the Borexino experiment confirms that radioactivity contributes a significant fraction -- possibly most -- of the power, he said.

The Borexino experiment actually was designed to detect low-energy solar neutrinos, not geo-neutrinos. "As we were building the experiment, we realized we had the capability of detecting particles that were coming at us from the radioactivity deep inside Earth," said Cristiano Galbiati, an assistant professor of physics and another of the 13 Princeton collaborators among the 88 scientists involved in the research.

The Borexino project is located nearly a mile below the surface of the Gran Sasso mountain about 60 miles outside of Rome -- an ideal spot for studying neutrinos because the rock shields the detector from other types of radiation and particles that would overwhelm the sensing device. Much of the Borexino experiment is a process of eliminating the "noise" of background radiation.

Neutrinos are notoriously difficult to detect because they usually pass straight through matter, rarely interacting with it. The detector is composed of a nylon sphere containing 1,000 tons of a hydrocarbon liquid. An array of ultrasensitive photodetectors is aimed at the sphere that is encased within a stainless steel sphere. All of this is surrounded by 2,400 tons of highly purified water held within another steel sphere measuring 59 feet.

Solar neutrinos produce one type of signal when they come into contact with the detector, and geo-neutrinos produce another type. Because there are a thousand times fewer geo-neutrinos striking the detector, there are only a few events that occur per year. The paper describes two years of results, running up to December 2009. The experiment is continuing.

The importance of geo-neutrinos was pointed out by scientists in the 1960s, and a seminal study by Lawrence Krauss, Sheldon Glashow and David Schramm in 1994 laid the foundation for the field. In 2005, a Japan-U.S. collaboration called KamLAND operating an experiment at a mine in Japan reported an excess of low-energy "antineutrinos."

Scientists can envision a day when a series of geo-neutrino-detecting facilities, located at strategic spots around the globe, can sense particles to get a detailed understanding of Earth's interior and the source of its internal heat. This data could provide enough information to predict the occurrence of events such as volcano eruptions and earthquakes.

Brain Size Associated With Longevity in Mammals

The brain size of some mammals is larger than expected for their body size. This is the case of large primates, such as chimpanzees and gorilla, and of whales, dolphins and elephants. Scientists have spent years investigating why sometimes nature favours the development of large brains given that they require much more time to reach functional maturity and use up so much energy. One of the classical explanations is the Cognitive Buffer Hypothesis (CBH). This hypothesis suggests that a larger brain provides more flexibility in behaviour when facing changes in the environment and makes learning easier, aspects which allow species to overcome ecological challenges successfully.

CREAF researchers César González-Lagos and Daniel Sol, together with Simon Reader (University McGill, Canada), offer new data supporting this hypothesis in an article published recently in Journal of Evolutionary Biology. Using statistical methods, the authors analysed data from 493 mammal species -- from rodents and bats to cetaceans, felines, ungulates and marsupials -- and have reached the conclusion that having a larger brain entails having a longer life, and this represents a new advantage.

In addition to generating more opportunities to adapt to changes and therefore improving survival, a larger brain size also permits animals to live longer and thus have more chances to reproduce, which is beneficial to each individual member. This is the compensation for a longer embryonic development needed to generate a larger brain. Species with larger brains have also shown to take longer in reaching sexual maturity, which is in part compensated by a longer reproductive life.

The study includes an extended taxonomic range in comparison to previous studies and takes into account phylogenetic relations between species analysed. Researchers analysed a series of other variables which could be related to higher longevity, such as metabolic rates -- the amount of energy expended while at rest -- diet or habitat, and concluded that none of these can be significantly associated with longevity. Connections are made however not only with a larger brain size, but also with a larger body size, given that large animals are known to live longer. Nevertheless, CREAF researchers confirm that the size of the brain affects lifespan regardless of the size of the body. Hyenas, for example, have a larger brain than giraffes in proportion to body size and on average live longer, although they are smaller than these herbivores.

The statistical model used by researchers also took into account whether age registers of the almost 500 species analysed were carried out with animals living in the wild or in captivity. The latter were shown to have more chances of living longer.

The authors of the study emphasise that the relation between a large brain and a longer life is not always one of cause and effect. "CBH points to this fact, that a larger encephalon favours a longer lifespan, but it is equally possible that a longer life favours the development of larger brains," researchers assure. Thus, it is possible that a longer life works in favour of a delay in reproductive cycles and this would in turn allow progenitors to invest more resources and time in caring for their offspring. This also leads to the formation of stable social groups whose members, according to the Social Intelligence Hypothesis (SIH), must deal with more cognitive demands than animals living alone, and this would be the reason for larger brains. "Our results," researchers add, "do not demonstrate which of the two options is correct, although we think that the two complement each other and go hand in hand."

Artificial lung "breathes" in rats: study

U.S. researchers have created a primitive artificial lung that rats used to breathe for several hours and said on Tuesday it may be a step in the development of new organs grown from a patient's own cells.

The finding, reported in the journal Nature Medicine, second in a month from researchers seeking ways to regenerate lungs from ordinary cells.

In the latest study, Harald Ott and colleagues at Massachusetts General Hospital and Harvard Medical School in Boston removed the cells from rat lungs to leave a scaffolding or matrix.

They soaked these in a bioreactor along with several types of human lung cells, creating pressures to simulate the pressure inside a body to make the lung workable and flexible.

The cells took up residence and grew into different tissue types seen in a lung, Ott's team reported.

When transplanted into rats, they worked for about six hours, although imperfectly.

The researchers said it may be possible to try the experiment with more immature stem cells, the body's master cells. These could include embryonic stem cells, which can mature into any cell type in the body, or induced pluripotent stem cells -- ordinary cells with genes added to make them behave like flexible stem cells.

The potential market is large and dozens of companies are launching into regenerative medicine, as are academic labs like those at Harvard.

"Nearly 25 million people live with chronic obstructive pulmonary disease and approximately 120,000 patients die from end-stage lung disease annually in the United States alone," Ott's team wrote.

"Lung transplantation remains the only definitive treatment for end-stage lung disease. As with other organs, however, the supply of donor lungs is limited. In 2005, only one out of four patients waiting for a lung underwent transplantation," they added, citing the United Network of Organ Sharing.

Last month, a team at Yale University in Connecticut implanted engineered lung tissue into rats that helped the animals breathe for two hours.

Better Animal-Free Test for Chemicals That Can Cause Contact Dermatitis

Their study appears in ACS'Chemical Research in Toxicology, a monthly journal.

Itai Chipinda and his colleagues note the existence of public sentiment against the use of animals to determine whether ingredients in consumer soaps, shampoos and other consumer products, and workplace chemicals, may cause skin sensitization and contact dermatitis. Chemicals cause dermatitis by bonding to proteins in the skin, and then aggravating the immune system so that redness, irritation, itching, and other symptoms occur.

Existing chemical tests use substances like glutathione that mimic skin proteins and bond to allergy-causing ingredients. None, however, are suitable for use in detecting the critical early stages of skin sensitization, the scientists say.

Instead of glutathione, Chipinda and his team developed a test with nitrobenzenethiol as the skin protein surrogate. When used on 20 different chemicals known to cause skin irritation, the test produced positive results. It produced negative results when used to test substances that usually do not produce skin sensitization.

"This simple, rapid and inexpensive absorbance-based method has great potential for use as a preliminary screening tool for skin allergens," the report states.

Could Our Minds Be Tricked Into Satisfying Our Stomachs?

Test subjects were more satisfied for longer periods of time after consuming varying quantities of food for which they were led to believe that portion sizes were larger than they actually were.

Memories about how satisfying previous meals were also played a causal role in determining how long those meals staved off hunger. Together, these results suggest that expectations before eating and memory after eating play an important role in governing appetite and satiety.

In the first experiment, participants were shown the ingredients of a fruit smoothie. Half were shown a small portion of fruit and half were shown a large portion. They were then asked to assess the 'expected satiety' of the smoothie and to provide ratings before and three hours after consumption. Participants who were shown the large portion of fruit reported significantly greater fullness, even though all participants consumed the same smaller quantity of fruit.

In a second experiment, researchers manipulated the 'actual' and 'perceived' amount of soup that people thought that they had consumed. Using a soup bowl connected to a hidden pump beneath the bowl, the amount of soup in the bowl was increased or decreased as participants ate, without their knowledge. Three hours after the meal, it was the perceived (remembered) amount of soup in the bowl and not the actual amount of soup consumed that predicted post-meal hunger and fullness ratings.

The findings could have implications for more effective food labeling.

"The extent to which a food that can alleviate hunger is not determined solely by its physical size, energy content, and so on. Instead, it is influenced by prior experience with a food, which affects our beliefs and expectations about satiation. This has an immediate effect on the portion sizes that we select and an effect on the hunger that we experience after eating," said Dr. Brunstrom.

"Labels on 'light' and 'diet' foods might lead us to think we will not be satisfied by such foods, possibly leading us to eat more afterwards," added Dr. Brunstrom. "One way to militate against this, and indeed accentuate potential satiety effects, might be to emphasize the satiating properties of a food using labels such as 'satisfying' or 'hunger relieving'."

The research was funded by the Biotechnology & Biological Sciences Research Council (BBSRC) and a consortium of food companies under a joint initiative with the Diet and Health Research Industry Club (DRINC).

The lead author was Jeff Brunstrom of the University of Bristol UK.

Co-authors were P Rogers, J Burn, Jm Collingwood, O Maynard, S Brown, N Sel also of the University of Bristol UK.

Scientists Create Replacement Fingers

Touchs Bionics,a Scottish company,has created a prothesis that can replace any or all fingers on a hand.The prothesis was recently fitted to a man whose fingers & thumb were amputed three years ago.The prothesis,named ProDigits is basically a set of motorised digits.Each replacement digit has a tiny motor & a gear box mounted at the base.Movement is controlled by a computer chip in the prothesis.Prodigits may be opened or closed not only by sensors that pick up muscle contractions,but also the fingres to detect pressures exacted by the remnant bone.The user starts the action by flexing or relaxing a muscle in the palm.Sensors in the prothesis pick up the signals sent by the muscles & send the message to the computer chip that controls the motor.

Silk Implant That Can Melt Into The Brain

As per a report published in the journal Nature Material on April19,2010,scientists at the university of Pennsylvania & Tufts University have created a revolutionary brain implant made partly of silk that can melt onto the surface of the brain.Tests of the device showed that the thin,flexible electrodes recorded signals from a cat's brain more accurately than thicker,stiff devices.The scientists made the electrode arrays using protein from silk & thin metal electrodes.

The silk is bio-compatible & water soluble,dissolving into brain & leaving the electrodes draped over its contours.the scientists tested the devices on cats who were anaesthestised but whose eyes were functioning.The electrodes recorded the signals from the eyes of the cats as they were shown images.

Synthetic Muscles To Let Paralysed People Blink

In a crucial breakthrough that may benefit thousands of people who cannot close their eyelids,scientists have showed that the artificial muscles(EPAM in fig;) can restore the ability of facial paralysis patients to blink.Illustration of left eyelid sling that is attached to the electroactive polymer artificial muscle device (EPAM) after passing through an interpolation unit that is implanted in the lateral orbital wall (note screw fixation). The power supply and artificial muscle are implanted in the temporal fossa. Conceptually, when the normal right eyelid blinks, the electrical sensor (green) sends a signal to the battery to activate the EPAM.

EPAM is an emerging technology that has the potential for use in rehabilitating facial movement in patients with paralysis. Electroactive polymers act like human muscles by expanding and contracting, based on variable voltage input levels.For patients who have one functioning eyelid, a sensor wire threaded over the normal eyelid could detect the natural blink impulse and fire the artificial muscle at the same time. Among patients lacking control of either eyelid, an electronic pacemaker similar to those used to regulate heartbeats could blink the eye at a steady rate, and be deactivated by a magnetic switch.

Scientists,however,are of the opinion that there are many ideas & concepts where this technology can play role.