Archive for the ‘SCIENCE / TECH’ Category
In India, children of the snake charmers in the village of Padmakesharpur are no strangers to cobras. Early-age encounters with devenomized cobra snakes, acclimatize babies to fearlessness of snakes.
A team of University of California, Los Angeles-led scientists has identified a protein with broad virus-fighting properties that potentially could be used as a weapon against deadly human pathogenic viruses such as HIV, Ebola, Rift Valley Fever, Nipah and others designated "priority pathogens" for national biosecurity purposes by the National Institute of Allergy and Infectious Disease.
In a study published in the January issue of the journal Immunity, scientists describe the novel antiviral property of the protein, cholesterol-25-hydroxylase; an enzyme that converts cholesterol to an oxysterol called 25-hydroxycholesterol, which can permeate a cell’s wall and block a virus from getting in. Interestingly, the cholesterol-25-hydroxylase enzyme is activated by interferon, an essential antiviral cell-signaling protein produced in the body, said lead author Su-Yang Liu, a student in the department of microbiology, immunology and molecular genetics at the David Geffen School of Medicine at University of California, Los Angeles.
Antiviral genes are hard to apply for therapeutic purposes because it is difficult to express genes in cells. Cholesterol-25-hydroxylase produces a natural, soluble oxysterol that can be synthesized and administered. Initial studies showed that 25-hydroxycholesterol can inhibit HIV growth in vivo prompts further study into membrane-modifying cholesterols that inhibit viruses. This discovery is particularly relevant to efforts to develop broad-spectrum antivirals against an increasing number of merging viral pathogens.
Working with Jerome Zack, a professor of microbiology, immunology and molecular genetics and an associate director of the University of California, Los Angeles AIDS Institute, the scientists initially found that 25-hydroxycholesterol inhibited HIV in cell cultures. Next, scientists administered 25-hydroxycholesterol in mice implanted with human tissues and found that it significantly reduced their HIV load within seven days. The 25-hydroxycholesterol also reversed the T-cell depletion caused by HIV and by contrast, mice that had cholesterol-25-hydroxylase gene knocked out were more susceptible to a mouse gammaherpes virus.
In collaboration with Dr. Benhur Lee, a professor of pathology and laboratory medicine and a member of the University of California, Los Angeles AIDS Institute, they discovered that 25-hydroxycholesterol inhibited HIV entry into the cell. In cell cultures, it was found to inhibit the growth of other deadly viruses, such as Ebola, Nipah and the Rift Valley Fever virus.
The cholesterol-25-hydroxylase expression in cells requires interferon. While interferon has been known for more than 60 years to be a critical part of the body’s natural defense mechanism against viruses, the protein itself does not have any antiviral properties. Rather, it triggers the expression of many antiviral genes. While other studies have identified some antiviral genes that are activated by interferon, this research gives the first description of an interferon-induced antiviral oxysterol through the activation of the enzyme cholesterol-25-hydroxylase. It provides a link to how interferon can cause inhibition of viral membrane fusion.
The weaknesses in the research is, for instance, 25-hydroxycholesterol is difficult to deliver in large doses, and its antiviral effect against Ebola, Nipah and other highly pathogenic viruses have yet to be tested in vivo. Scientists still need to compare 25-hydroxycholesterol’s antiviral effect against other HIV antivirals.
The University of California, Los Angeles AIDS Institute, established in 1992, is a multidisciplinary think tank drawing on the skills of top-flight scientists in the worldwide fight against HIV and AIDS, the first cases of which were reported in 1981 by University of California, Los Angeles physicians. Institute members include researchers in virology and immunology, genetics, cancer, neurology, ophthalmology, epidemiology, social sciences, public health, nursing and disease prevention. Their findings have led to advances in treating HIV, as well as other diseases, such as hepatitis B and C, influenza and cancer.
For more news, visit the University of California, Los Angeles Newsroom.
While the test object is moved through the X-ray beam with nanometer precision, the scattered X-rays are captured by a detector. The scattering images are then reconstructed to an image of the sample. Credit: Technische Universitaet Muenchen / Paul Scherrer Institute, Villigen (Switzerland)
X-ray microscopy requires radiation of extremely high quality. In order to obtain sharp images instrument and sample must stay absolutely immobile even at the nanometer scale during the recording. Researchers at the Technische Universitaet Muenchen and the Paul Scherrer Institute in Villigen, Switzerland, have now developed a method that relaxes these hard restrictions. Even fluctuations in the material can be visualized. The renowned journal Nature now reports on their results.
For more than 100 years radiography meant: don’t move! In order to visualize nanostructures such as biological cells, the porous structure of cement or storage fields of magnetic disks, the experimentators had to avoid any kind of vibration of X-ray microscope and sample. In addition, only a small percentage fraction of the incoming X-ray radiation could be used. Using special filters, they had to select exactly the fraction with the right properties, for example, the right wavelength.
Contributions of different wavelengths separated Pierre Thibault of the Technische Universitaet Muenchen and Andreas Menzel, scientist at the Paul Scherrer Institute Villigen, Switzerland have now developed an interpretation method that produces reliable images in spite of vibrations or fluctuations. The method is based on a technique called ptychography, developed in the 1960s for electron microscopy. Thibault and Menzel’s advancements now make it possible to distinguish effects originating from the contribution of different types of X-ray waves.
croscopic image (right). Credit: Technische Universitaet Muenchen / Paul Scherrer Institute, Villigen (Switzerland)
The most significant result of the study is that it gives access to a whole class of objects that previously could hardly be investigated. Scientists now not only can compensate for the vibrations in the microscope. Scientists can even characterize fluctuations of the sample itself, even if they are much too fast to be seen with individual snapshots. Scientists needed to convince themselves that the images they produced did indeed reflect accurately the samples and their dynamics. So scientists carried out computer simulations. They confirmed that effects of the instrument as well as of the sample itself, such as flows, switching events or mixed quantum states, can be characterized.
The new method combines the characterization of dynamical states with high-resolution X-ray microscopy. One possible application is to analyze the changing magnetization of individual bits in magnetic storage media with high storage density. The interactions of such single magnetic bits or their thermal fluctuations, which ultimately determine the lifetime of magnetic data storage, could be visualized. In addition to its use in imaging, the analysis method also reveals a fundamental relationship to other disciplines of Microscopy and scientific disciplines such as quantum computing, previously regarded as independent, can benefit from each other here.
More Information: Reconstructing state mixtures from diffraction measurements, Pierre Thibault & Andreas Menzel, Nature, 7 February 2013, DOI: 10.1038/nature11806 Journal reference: Nature
Astronomers have discovered the largest structure yet seen in the universe, a clump of quasars so large that it would take light 4 billion years to traverse its widest dimension. Light from these quasars started its journey when the universe was only 5 billion years old, the researchers say. Far larger than previously discovered groups of quasars, the structure (artist’s depiction of a single quasar) is so large that it challenges Albert Einstein’s cosmological principle; the notion that the universe, at large scales, looks the same no matter the direction and locale from which you look. According to that theory, the researchers says, the universe’s large-scale structures—in this case, clumps of objects such as quasars—shouldn’t be larger than 1.2 billion light-years across. The elongated, newly discovered large quasar group is, on average, about 1.63 billion light-years across but in its largest dimension is more than 4 billion light-years across, the researchers report today in Monthly Notices of the Royal Astronomical Society. By comparison, typical clusters of galaxies can be nearly 10 million light-years across. Bringing the comparison to our cosmic neighborhood, the new record-holding group of quasars spans about 1600 times the distance between our Milky Way galaxy and our neighbor Andromeda.
Eyjafjallajökull Volcano Eruption
One of my favorite books is about a pair of identical twins who decided to switch clothes. They looked so much alike that their parents had had to dress one in blue and the other in green. The twin boys fooled their parents for a long time. I am thrilled by their ingenuity and boldness. Though parents can usually tell the difference between their identical twins, grandparents, teachers, neighbors and peers sometimes cannot and for good reasons. Identical twins very often look almost exactly alike. No surprise there, if identical twin share their entire DNA.
Identical twins may not be so identical after all. Even though identical twins supposedly share their entire DNA, they acquire hundreds of genetic changes early in development that could set them on different paths, according to new research. The findings, presented at the American Society of Human Genetics meeting, may partly explain why one twin gets cancer while another stays healthy. The study also suggests that these genetic changes are surprisingly common. It’s not as rare as people previously expected. While past studies have looked at genetic changes or mutations, in sperm and eggs, which can be passed on to offspring, very few studies have looked at somatic mutations. These mutations, also called copy errors, can occur early in fetal development, but because they aren’t in the sex cells (the X or Y chromosomes) of the fetus, they can’t be passed on. Other studies have shown that chemical modifications or epigenetic effects can change which genes are expressed over the years, one factor that renders twins not completely identical. Still, other work has shown that identical twins can have different gene mutations, but this study didn’t determine how often they occur.
To find out how often these mutations occur in early development, Li and her colleagues studied the genomes of 92 pairs of identical twins and searched hundreds of thousands of sites in their genomes for differences between twins in base pairs, which are represented by letters that make up DNA. For instance, one twin may carry an A at one point while another carries a C. The researchers could only detect differences that would occur very early in fetal development and would show up in most cells in the body.
They then calculated the frequency with which these mutations occurred. Only two sets of twins had such mutations, which translates to a DNA change occurring once for every 10 million to 10 billion bases that are copied every time a cell divides. While that may seem like a high accuracy rate, cells in the body divide trillions of times. So that would mean an average twin pair carries 359 genetic differences that occurred early in development. One limitation of the study is that they could only estimate the mutation rate based on blood cells, but some cells in the body divide much more frequently and so may rack up many more mutations. Other cells, like brain cells, don’t regenerate much and would probably remain stable. We need to define different rates in different tissues.
This research presented at the 2012 American Society of Human Genetics meeting, however, suggests that identical twins may not be as genetically similar as hitherto suggested. Identical, or monozygotic, twins come from the same fertilized egg. So, at some point during cell division (before 14 days post-conception), identical twin embryos share virtually their entire DNA. During early fetal development, however, identical twins undergo more than 300 genetic mutations or copy errors, on average. As human cells divide trillions of times during their lifespan, a few hundred genetic mutations could lead to millions or trillions of genetic differences in the DNA of identical twins over the years. Chemical factors can furthermore activate or suppress gene expression, which means that the same subset of genetic material can lead to the formation of different proteins.
The results, which were presented by McGill University epidemiologist Rui Li, could have drastic consequences for what we know about the heritability of diseases, addictions, personality and intelligence—or what is more popularly known as the nature versus nurture debate.
A good chunk of the information we have about whether traits are passed down from parent to child through genes or whether they are a result of the environment comes from the Minnesota Study of Twins Reared Apart. The Minnesota Twin Study is a project originally led by Minnesota Professor of Psychology Thomas Joseph Bouchard, Jr. The initial project took place from 1979 to 1999 and consisted in periodical educational, psychological, medical and dental testing of individuals in an extensive population of identical (monozygotic) and fraternal (dizygotic) twins and their families.
Starting around 1990 Professor Bouchard and his team published numerous results from the twin study project. The majority of the conclusions of the twin studies are based on answers to the question of whether identical twins (who were thought to share all their genes) are more similar than those of fraternal twins (who share an average of 50 percent of their genes). It was concluded, among many other things, that identical twins are about 85 percent similar for IQ, whereas fraternal twins are about 60 percent similar. This would seem to indicate that half of the variation in intelligence is due to genes.
What, then, are the consequences of the recent discovery that identical twins are not completely genetically identical for the results of the Minnesota Twin Study? The answer to that question depends on how different identical twins are. Assuming that early fetal genetic mutations multiply significantly as time passes, there may be reason to question some of the previous twin study results. The main conclusions at risk are those that concern traits, diseases and conditions that we thought were a result of environmental influences.
Suppose a large number of pairs of identical twins separated at birth turn out to have very similar IQs. Setting aside skepticism about IQ tests as a measure of intelligence, we should be able to conclude that the environment does not significantly affect intelligence. The studies done by Li and her colleagues do not affect this conclusion in any interesting way. However, suppose that we find that a large population of pairs of twins separated at birth have very different IQs. Can we conclude that intelligence isn’t inherited? The answer to this question is "no." The reason for this is that variation in intelligence may be grounded in genetic material that identical twins do not share. So the environment could affect intelligence a lot less than we once thought.
Li and her colleagues used blood cells to calculate mutation rates. As blood cells divide slower than most other cells in the body, the consequences for diseases, for example cancer, could be more austere than we think. That is, some diseases that we believe are not genetic could be genetic after all. Blood cells, however, divide faster than brain cells. So, genetic differences in brain-based traits, such as personality and intelligence, may not be as austere as differences elsewhere.
Tags: american society of human genetics, chemical factors, drastic consequences, epidemiologist, fetal development, gene expression, genetic differences, genetic mutations, heritability, human cells, identical and fraternal twins, intelligence and iq, long long time, mcgill university, minnesota study, minnesota twin, minnesota twin studies, monozygotic twins, nature versus nurture, nature versus nurture debate, personality and intelligence, society of human genetics, twin share.
Lou, who once set several major league baseball records, suddenly could barely keep his body upright during practice. He would fall while running bases, stumble over curbs and mishandle fielding plays. His wife, Eleanor, was concerned. Her husband held records for most consecutive games played, 2131 to be exact, and most career grand slams. Though Lou said it was just a phase, Eleanor got on the phone with the Mayo Clinic in Rochester, Minnesota. Charles William Mayo wanted them to come right away. They arrived on June 13, 1939 and six days later on Lou’s thirty-sixth birthday the doctors told Eleanor that her husband suffered from amyotrophic lateral sclerosis. Lou Gehrig died less than two years later.
Amyotrophic lateral sclerosis, which has later come to be known as Lou Gehrig’s disease, is a disease of the neurons in the brain and spinal cord that control voluntary muscle movement. Symptoms start off relatively mild with some muscle weakness. But as the disease progresses the muscle weakness worsens. Patients become incapable of moving their arms and legs, as the muscles controlling movement waste away. In the final stages of the disease, weakening of the diaphragm and rib cage muscles typically causes respiratory failure. What’s perhaps the most devastating part of the disease is that the mind stays as healthy as ever during the progressive deterioration of the muscles. Some people with amyotrophic lateral sclerosis are bed stricken and paralyzed for months without the ability to communicate or swallow and with difficulties breathing. At that point we might say that death is a breeze.
Amyotrophic lateral sclerosis is a special case of locked-in syndrome, a condition that became ingrained into the minds of the public in 2007 with the release of the French bio-drama The Diving Bell and the Butterfly, based on Jean-Dominique Bauby’s biography of the same name. On December 8, 1995 Bauby suffered a massive stroke that left him paralyzed from the neck down. He was left with only one eye after doctors decided to sew up his right eye to prevent infection. In the months to follow he struggled to convince his lover (in the movie: his wife) and the nurses that cared for him that there was a conscious mind behind the dead body and that the flickering of the left eyelid was not erratic tics. He succeeded and authored his biography using only the left eyelid and a human translator; initially one of the nurses.
For sufferers of locked-in syndrome the success of synthetic, or artificial, telepathy would be more than a scientific breakthrough. It would add meaning to the final years of mentally healthy people who cannot move, talk or eat. Synthetic telepathy is direct communication between the brain and an external device, communication that does not require any hand movements or voice activation.
Research on synthetic telepathy started in the 1970s at UCLA. From its conception, the research was aimed at developing neuroprosthetics that can control external electronic devices. The initial research was done on animals, starting with rodents and slowly moving up to primates. In 2008, researchers at the University Pittsburgh Medical Center succeeded in training a monkey with a neuroprosthetic to operate a robotic arm via thought alone.
The first neuroprosthetic devices were implanted in human brains in the mid- to late-1990s. In 1997 Emory University researchers Philip Kennedy and Roy Bakay; who is now at Rush University Medical Center, started working with Johnny Ray, who suffered from locked-in syndrome following a brainstem stroke that same year. Ray had a neuroprosthetic successfully implanted in 1998. Over the next four years, he learned to control a computer cursor via thought alone. In 2005 tetraplegic Matt Nagle received a neural implant and became the first human to control an artificial hand by thinking about moving his hand. Subsequently, he also learned to control a computer cursor, a light switch and a television set.
To ensure competitiveness in the face of the Arab spring and the potential US-China military conflict the US military decided to fund synthetic telepathy research in 2008. The military grant money was aimed at research into the development of emails, text and voice messages using thought alone. This could be beneficial for use by undercover agents, prisoners of war and front line soldiers alike. If you can send emails or text messages via thought alone, there is no risk of being cut off from the electronic pipeline. People can quickly come to your rescue when you need them, and information about foreign military development can reach the US spy-camp back in the homeland without you moving a finger.
How is thought-controlled messaging even possible? The current technique is based on a device that is used to read brain signals, called electroencephalography. Electroencephalography is the recording of electrical signals, or brain waves, along your scalp. The technique is primarily used to measure deviations in standard brain wave fluctuations and can be used to determine whether a patient has a seizure, is in a coma or is brain dead. The normal awake brain has activity that fluctuates between 8 and 100 Hz. An alert and active brain will tend to have neural oscillations, roughly, in the 40 Hz range in at least some parts of the brain. These brain waves are also known as gamma waves. Alpha waves — oscillations in the 8 to 12 Hz frequency range — and beta waves — oscillations in the 12 to 30 Hz range — become more prominent when you are inactive, for example, when passively watching television. Brain-dead people and coma patients can have oscillations that approach zero. In seizure patients, the brain oscillates faster and more regions of the brain vacillate in the same frequency range. In a grand mal seizure, large areas of the brain flicker in synchrony.
Like other brain scanning devices, such as positron emission tomography and functional magnetic resonance imaging, electroencephalography can read which parts of your brain are most or least active by measuring how fast neurons in different regions oscillate. So if we know that a particular part of your brain oscillates in the gamma range when you think “Help. The enemy caught me” but oscillates in the alpha range when you think “Everything is cool here,” we can program a computer to translate these signals into a message.
While we already have commercial electroencephalography games, such as Mindball, that allow gamers to manipulate virtual objects by thought alone, electroencephalography messaging may not be just around the corner for the majority of us. Electroencephalography is simply not very sensitive when used on the outside of the scalp. In Mindball, the electroencephalography device measures which of the players have neural oscillations in the lowest frequency range. This player’s ball then moves across a table; presumably the one who fall asleep or consumed most Valium wins.
One of the military-funded researchers Mike D’Zmura from UC Irvine thinks that while most of the funded research will be utilized by the military, the research will result in the development of commercial products as soon as the technology is there to support it. Fifteen years ago the thought of sitting on opposite sides of the globe communicating face-to-face, as we do with Skype, was at best a sci-fi comedy. Now we use it on a daily basis.
Because of the insensitivity of electroencephalography, electroencephalography helmets are most likely never going to be a way to conduct business meetings or presidential debates. But there is really nothing else out there that would work for commercial purposes. You cannot carry functional magnetic resonance imaging scanner around on your shoulders in order to direct graduate students or play Angry Bird using thought only. Implants are more sensitive than electroencephalography wrapped around your head because they are placed under the scalp. But it’s unlikely that invasive devices will be Food and Drug Administration-approved for the ordinary commercial market any time soon.
One of the main worries people have about thought-controlled text and email messaging is that they will have no privacy left. Dare think a single thought about the woman having dinner at the next table and your spouse will slap your face and leave. But, of course, this is not how these devices will ultimately work. People had the same concerns about Skype-like phone calls.
“Oh no, what will happen if I just came out of the shower and the phone rings,” your granny would ask and look seriously worried.
“Well, the device would have an on-off switch,” you would calmly reply, but the worried look would not go away.
People apparently didn’t trust themselves enough to even think it would be possible not to pick up the phone naked on their way out of the shower.
But that was then. Today, hardly anyone picks up the phone and there probably are very few people who have accidentally accepted a Skype call naked. In 10 or 15 years, when thought-controlled texting and emailing might be commercially available, it is going to be just as unlikely that you are most naughty, rude or immoral thoughts are going to be transferred by sheer accident to the salesperson at the liquor store or your spouse during your anniversary dinner. In fact, you probably will be more concerned about your kids thinking too much to each other at the dinner table instead of eating their vegetables than about you thinking something inappropriate yourself.
Common methods of functional neuroimaging include:
Positron emission tomography (PET),
Functional magnetic resonance imaging (fMRI),
Multichannel electroencephalography (EEG),
Near infrared spectroscopic imaging (NIRSI), and
Single photon emission computed tomography (SPECT)