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Many researchers believe that physics will not be complete until it can explain not just the behaviour of space and time, but where these entities come from.
“Imagine waking up one day and realizing that you actually live inside a computer game,” says Mark Van Raamsdonk, describing what sounds like a pitch for a science-fiction film. But for Van Raamsdonk, a physicist at the University of British Columbia in Vancouver, Canada, this scenario is a way to think about reality. If it is true, he says, “everything around us — the whole three-dimensional physical world — is an illusion born from information encoded elsewhere, on a two-dimensional chip”. That would make our Universe, with its three spatial dimensions, a kind of hologram, projected from a substrate that exists only in lower dimensions.
This 'holographic principle' is strange even by the usual standards of theoretical physics. But Van Raamsdonk is one of a small band of researchers who think that the usual ideas are not yet strange enough. If nothing else, they say, neither of the two great pillars of modern physics — general relativity, which describes gravity as a curvature of space and time, and quantum mechanics, which governs the atomic realm — gives any account for the existence of space and time. Neither does string theory, which describes elementary threads of energy. Van Raamsdonk and his colleagues are convinced that physics will not be complete until it can explain how space and time emerge from something more fundamental — a project that will require concepts at least as audacious as holography.
But, where is the evidence that there actually is anything more fundamental than space and time? A provocative hint comes from a series of startling discoveries made in the early 1970s, when it became clear that quantum mechanics and gravity were intimately intertwined with thermodynamics, the science of heat. In 1974, most famously, Stephen Hawking of the University of Cambridge, UK, showed that quantum effects in the space around a black hole will cause it to spew out radiation as if it was hot. Other physicists quickly determined that this phenomenon was quite general. Even in completely empty space, they found, an astronaut undergoing acceleration would perceive that he or she was surrounded by a heat bath. The effect would be too small to be perceptible for any acceleration achievable by rockets, but it seemed to be fundamental. If quantum theory and general relativity are correct — and both have been abundantly corroborated by experiment — then the existence of Hawking radiation seemed inescapable.
A second key discovery was closely related. In standard thermodynamics, an object can radiate heat only by decreasing its entropy, a measure of the number of quantum states inside it. And so it is with black holes: even before Hawking's 1974 paper, Jacob Bekenstein, now at the Hebrew University of Jerusalem, had shown that black holes possess entropy. But there was a difference. In most objects, the entropy is proportional to the number of atoms the object contains, and thus to its volume. But a black hole's entropy turned out to be proportional to the surface area of its event horizon — the boundary out of which not even light can escape. It was as if that surface somehow encoded information about what was inside, just as a two-dimensional hologram encodes a three-dimensional image.
In 1995 then, Ted Jacobson, a physicist at the University of Maryland in College Park, combined these two findings, and postulated that every point in space lies on a tiny 'black-hole horizon' that also obeys the entropy–area relationship. From that, he found, the mathematics yielded Einstein's equations of general relativity — but using only thermodynamic concepts, not the idea of bending space-time. Ted's result suggested that gravity is statistical, a macroscopic approximation to the unseen constituents of space and time.
In 2010, this idea was taken a step further by Erik Verlinde, a string theorist at the University of Amsterdam, who showed that the statistical thermodynamics of the space-time constituents — whatever they turned out to be — could automatically generate Newton's law of gravitational attraction. In separate work, Thanu Padmanabhan, a cosmologist at the Inter-University Centre for Astronomy and Astrophysics in Pune, India, showed that Einstein's equations can be rewritten in a form that makes them identical to the laws of thermodynamics — as can many alternative theories of gravity. Padmanabhan is currently extending the thermodynamic approach in an effort to explain the origin and magnitude of dark energy: a mysterious cosmic force that is accelerating the Universe's expansion.
Via Dr. Stefan Gruenwald
In the wee hours of an April morning some 27 years ago, the nearly 50,000 residents of the Soviet city of Pripyat slept soundly as the worst nuclear disaster in history unfurled just down the street. Less than two miles away, a reactor at the Chernobyl Nuclear Power Plant erupted, sending a plume of radioactive material spiraling into the atmosphere. The resulting reactor fire burned for 10 days, spewing 20 Hiroshima bombs-worth of radioactive material across the environment and into animals, crops, and water sources, contaminating them, according to the International Atomic Energy Agency (IAEA).
In the subsequent years the IAEA estimates that 336,000 people would be evacuated or relocated from the most irradiated areas surrounding the plant, 116,000 of which were evacuated by the end of the summer of 1986. But the residents of Pripyat had just 36 hours -- 36 hours to abandon everything they knew, leaving the city's streets to rot and decay under the weight of the elements.
Now, long after the radioactive dust had settled, fine art photographer Philip Grossman returned to the area to document a different side of the incident, the cleanup. His work, "500,000 Voices," highlights the more than half a million workers, known as liquidators, who flooded the disaster site after the explosion, risking their lives to minimize the environmental hazards of mass nuclear contamination.
"Everything in the city is contaminated," said Grossman. "They moved as fast as they could to clean up, packing all the material that was radioactive into garbage bags and trucks and burying it."
Grossman, who also works as a senior director of content acquisition for The Weather Channel, has visited the area three times, drawing inspiration for his work from the unique setting of his childhood. "I grew up near Three Mile Island, so I've always had a fascination with what happened there, as well as what happened in Chernobyl," said Grossman. "I wanted to go to Chernobyl and do something that few people can, or want to do."
Grossman's work exhibits an exclusive flair; bribes and insider connections have helped Grossman make the most of his 24 days in the zone. On his first trip, Grossman gained access to the control room of reactor number four. On subsequent trips Grossman reached the top of nearly every structure in Pripyat, including the iconic Ferris wheel in the heart of the city, and the Fujiyama building, the tallest structure in the abandoned city. In all, Grossman's work covers nearly every square inch of the exclusion zone, painting an eerie picture of the environmental fallout of a nuclear catastrophe
Maybe no site encapsulates the environmental impact of the Chernobyl meltdown more than the Red Forest. In the immediate aftermath of the explosion, the four-square-kilometer-stretch of pine trees just outside the walls of the power plant absorbed 80 to 100 Grays of gamma radiation, according to the IAEA, enough to kill all of the trees and leave the rotting stumps a reddish-brown hue. In response, the hoards of liquidators leveled most of the forest, burying irradiated trees under layers of sediment in massive trenches. The confines of the Red Forest were then re-imagined as a massive graveyard for contaminated materials -- helicopters, trucks, bodies, soil, anything exposed to radiation -- were all dumped en masse. Even though the Red Forest has since regrown, the area remains one of the most radioactive environments in the world; levels of radiation in the forest can reach 1 roentgen, 50,000 times greater than average background radiation levels, according to the IAEA.
Via Dr. Stefan Gruenwald
A disease which robs children of the ability to walk and talk has been cured by pioneering gene therapy to correct errors in their DNA, say doctors. The study, in the journal Science, showed the three patients were now going to school. A second study published at the same time has shown a similar therapy reversing a severe genetic disease affecting the immune system.
Gene therapy researchers said it was a "really exciting" development.
Both diseases are caused by errors in the patient's genetic code - the manual for building and running their bodies.
Babies born with metachromatic leukodystrophy appear healthy, but their development starts to reverse between the ages of one and two as part of their brain is destroyed. Wiskott-Aldrich syndrome leads to a defective immune system. It makes patients more susceptible to infections, cancers and the immune system can also attack other parts of the body.
The technique, developed by a team of researchers at the San Raffaele Scientific Institute in Milan, Italy, used a genetically modified virus to correct the damaging mutations in a patient's genes.
Bone marrow stem cells are taken from the patient then the virus is used to 'infect' the cells with tiny snippets of DNA which contain the correct instructions. These are then put back into the patient.
Three children were picked for treatment from families with a history of metachromatic leukodystrophy, but before their brain function started to decline.
Prof Luigi Naldini, who leads the San Raffaele Telethon Institute for Gene Therapy, said: "Three years after the start of the clinical trial the results obtained from the first six patients are very encouraging.
"The therapy is not only safe, but also effective and able to change the clinical history of these severe diseases.
"After 15 years of effort and our successes in the laboratory, but frustration as well, it's really exciting to be able to give a concrete solution to the first patients."
Via Dr. Stefan Gruenwald
Marine biologists from Taiwan and New Zealand have identified four new species of deep-sea fish in the anglerfish genus Chaunax.
The Chaunacidae is a group of medium-sized fishes inhabiting the continental slope at depths of up to 1.6 miles (2.5 km).
The newly discovered species, named Chaunax flavomaculatus, C. mulleus, C. reticulatus and C. russatus, have been described in a paper published in the journal Zootaxa.
Chaunax flavomaculatus is about 4 – 5 inches (10 – 12 cm) in length and lives at depths of 1,150-1,312 feet (350 – 400 m).
The specific name of Chaunax flavomaculatus derives from the Latin wordsflavo (yellow) and maculates (spot), in reference to the fresh coloration of the dorsal body. The proposed common name of the species is Yellowspot frogmouth.
“Chaunax flavomaculatus is most similar to C. abei and C. endeavouri, with which it shares a mix of numerous bifurcated and simple dermal spinules.Chaunax flavomaculatus is unique in having many large yellow spots on the pinkish background of the dorsal surface when fresh, and a creamy white body when preserved,” the biologists wrote in the Zootaxa paper.
Via Dr. Stefan Gruenwald
A genetically modified purple tomato that is tastier than normal varieties and can last for more than a month before going off has been invented by scientists. The GM tomato, which gains its unusual color from a natural pigment known as anthocyanin, could be picked and shipped later due to its longer shelf life, allowing more time for flavour to develop on the vine.
Tests showed the shelf life of the tomatoes more than doubled from an average of 21 to 48 days after genetic modification, and they were less likely to go mouldy after harvest.
The strain has also been found in earlier studies to fight cancer in mice due to its high levels of antioxidants, and scientists say its qualities could be replicated in other soft fruits like strawberries and raspberries.
The tomatoes were modified by scientists at the John Innes Centre in Norfolk to contain two genes from the snapdragon which “switch on” a set of dormant genes in the tomato, causing them to produce more anthocyanin.
The pigment occurs naturally in various plants and flowers, and is responsible for many of the blues, reds and purples seen in nature, but also ramps up levels of antioxidants.
The goal of the project was to produce fruit with higher antioxidant levels which could benefit health, and earlier studies have shown that they helped extend the lives of cancer-prone mice by 30 per cent.
Via Dr. Stefan Gruenwald
Medical researchers think specially tailored RNA sequences could turn off genes in patients’ cells to encourage wound healing or to kill tumor cells. Now researchers have developed a nanocoating for bandages that could deliver these fragile gene-silencing RNAs right where they’re needed (ACS Nano 2013, DOI:10.1021/nn401011n). The team hopes to produce a bandage that shuts down genes standing in the way of healing in chronic wounds.
Small interfering RNAs, or siRNAs, derail expression of specific genes in cells by binding to other RNA molecules that contain the code for those genes. Biologists have developed siRNAs that target disease-related genes. But for these siRNAs to reach the clinic, researchers must find a way to deliver the molecules safely to the right cells. Unfortunately, free oligonucleotides like siRNAs don’t fare well inside the body or cells as enzymes and acids quickly chop them up, says Paula T. Hammond, a chemical engineer at Massachusetts Institute of Technology.
Other groups have tackled this delivery challenge by attaching siRNAs to chemical carriers that protect the oligonucleotides as they travel through the bloodstream. The pharmaceutical company Sanofi-Aventis asked Hammond to design a vehicle that would work at the site of a wound or tumor, releasing the siRNAs over a long period of time. The company hoped that putting the biomolecules right where they’re needed, without them having to survive a trip through the bloodstream, would increase the efficacy of the treatment.
Hammond and her colleagues produced an siRNA-containing nanocoating that could be applied to a wide range of medical materials, such as bandages or biodegradable polymers doctors could implant during surgery to prevent an excised tumor from coming back. As the coating slowly dissolves, it releases siRNA molecules tethered to protective nanoparticles.
The thin films consist of two different materials: a peptide called protamine sulfate and calcium phosphate nanoparticles decorated with the therapeutic siRNAs. Other researchers have shown that similar nanoparticles help the nucleotides evade destruction once they’re taken up by cells (J. Controlled Release 2010, DOI: 10.1016/j.jconrel.2009.11.008).
The team alternately dips whatever they want to coat in water solutions of the two materials. The RNA and nanoparticles are negatively charged, and the peptides are positively charged. The two substances cling together due to electrostatic force, producing a film when the water dries.
To test their delivery method, the researchers coated woven nylon bandages with 80-nm-thick films and applied the bandages to layers of human and animal cells in culture. In one experiment, a bandage loaded with 19 µg of siRNA per square centimeter released two-thirds of its load over 10 days. Other bandages made using siRNAs targeting the gene for fluorescent green protein almost completely shut down the protein’s production in cells expressing the gene. Hammond says the group is now testing bandages that knock down MMP9, a collagen-destroying protein associated with slow healing in chronic wounds.
Via Dr. Stefan Gruenwald
Scientists discovered unique cellular and molecular mechanisms behind tooth renewal in American alligators (Alligator mississippiensis).
Humans naturally only have two sets of teeth – baby teeth and adult teeth. Ultimately, we want to identify stem cells that can be used as a resource to stimulate tooth renewal in adult humans who have lost teeth. But, to do that, we must first understand how they renew in other animals and why they stop in people,” Prof Chuong said.
Whereas most vertebrates can replace teeth throughout their lives, human teeth are naturally replaced only once, despite the lingering presence of a band of epithelial tissue called the dental lamina, which is crucial to tooth development.
Because alligators have well-organized teeth with similar form and structure as mammalian teeth and are capable of lifelong tooth renewal, the team reasoned that they might serve as models for mammalian tooth replacement.
“Alligator teeth are implanted in sockets of the dental bone, like human teeth. They have 80 teeth, each of which can be replaced up to 50 times over their lifetime, making them the ideal model for comparison to human teeth,” explained study lead author Prof Ping Wu, also from the University of Southern California.
The team found that each alligator tooth is a complex unit of three components – a functional tooth, a replacement tooth, and the dental lamina – in different developmental stages. The tooth units are structured to enable a smooth transition from dislodgement of the functional, mature tooth to replacement with the new tooth. Identifying three developmental phases for each tooth unit, the researchers conclude that the alligator dental laminae contain what appear to be stem cells from which new replacement teeth develop.
“Stem cells divide more slowly than other cells,” said co-author Prof Randall Widelitz of the University of Southern California.
“The cells in the alligator’s dental lamina behaved like we would expect stem cells to behave. In the future, we hope to isolate those cells from the dental lamina to see whether we can use them to regenerate teeth in the lab.”
The team also intends to learn what molecular networks are involved in repetitive renewal and hope to apply the principles to regenerative medicine in the future.
Via Dr. Stefan Gruenwald
Just after the Big Bang, the Universe's dimensions may have been completely different to the four-dimensional space-time we know and love today.
Shortly after the Big Bang, the Universe possessed only one dimension of space and one dimension of time. It was basically a straight line. As the Universe began to cool, and expanded, this one dimension of space became “wrapped up” in such a way to create two dimensions of space and one of time — a plane, like a sheet of flat paper.
The transition from one to two dimensions of space was calculated by the researchers to occur when the Universe “cooled” to an energy level of 100 TeV (tera-electron volts, a measurement of energy commonly used in particle physics). A period of time after that, the Universe continued to expand and cool until it reached an energy of 1 TeV. At this point, the Universe got promoted to a higher dimension; three dimensions of space and one dimension of time, i.e., the Universe we live in today.
Mureika and Stojkovic think the Universe will eventually be promoted again, to a five-dimensional state, at some point in the future.
Via Dr. Stefan Gruenwald
It's only a small thing, but it could be big news: researchers at CERN have turned up the first evidence of exotic (and short-lived) atoms with pear-shaped nuclei.
The reasons the boffins are excited is they believe the eccentric nuclei can help them probe one of physics' official Big Questions: how come there's something instead of nothing?
Instead of the more typical profile for a nucleus – spherical or elliptical – the “pear shaped” nuclei were created by whacking beams of radium and radon atoms into targets of nickel, cadmium and tin, using CERN's ISOLDE ion separator facility. The collisions excited the nuclei to energy levels at which they revealed their internal structures via the patterns of gamma rays they gave off.
According to University of Michigan professor and co-atom-squeezer Tim Chupp, the pear shape “means the neutrons and protons, which compose the nucleus, are in slightly different places along an internal axis.”
That's special because the placement of the neutrons and protons provides hints at the subatomic interactions taking place.
Drilling into this is tortuous, but let's make the attempt. The reason this universe exists and we're here to wonder about it is that for some reason, back at Big Bang time, we ended up with a small asymmetry: there was more matter than antimatter. If matter and antimatter had been perfectly in balance, they would have annihilated each other.
To make the quest for a reason even more tasty: there's nothing in the Standard Model that predicts the matter-antimatter asymmetry.
Hence experiments such as this one: the researchers hope exotic atoms will hint at interactions that aren't seen in normal matter, and that by analysing those interactions, they can shed light on why we're all here.
One suggestion is that a type of interaction not yet written into the Standard Model exists – and if it does, its nature might be revealed in the relationship between the axis of atomic nuclei and their spin. In the pear-shaped nuclei, nuclear forces are presumed to be pushing the protons away from the centre of the nucleus – and that's what has Chupp's interest.
Via Dr. Stefan Gruenwald
Most species of gigantic animals that once roamed Australia had disappeared by the time people arrived, a major review of the available evidence has concluded.
The research challenges the claim that humans were primarily responsible for the demise of the megafauna in a proposed "extinction window" between 40,000 and 50,000 years ago, and points the finger instead at climate change.
An international team led by the University of New South Wales, and including researchers at the University of Queensland, the University of New England, and the University of Washington, carried out the study. It is published in the Proceedings of the National Academy of Sciences.
"The interpretation that humans drove the extinction rests on assumptions that increasingly have been shown to be incorrect. Humans may have played some role in the loss of those species that were still surviving when people arrived about 45,000 to 50,000 years ago -- but this also needs to be demonstrated," said Associate Professor Stephen Wroe, from UNSW, the lead author of the study.
"There has never been any direct evidence of humans preying on extinct megafauna in Sahul, or even of a tool-kit that was appropriate for big-game hunting," he said.
About 90 giant animal species once inhabited the continent of Sahul, which included mainland Australia, New Guinea and Tasmania.
"These leviathans included the largest marsupial that ever lived -- the rhinoceros-sized Diprotodon - and short-faced kangaroos so big we can't even be sure they could hop. Preying on them were goannas the size of large saltwater crocodiles with toxic saliva and bizarre but deadly marsupial lions with flick-blades on their thumbs and bolt cutters for teeth," said Associate Professor Wroe.
The review concludes there is only firm evidence for about 8 to 14 megafauna species still existing when Aboriginal people arrived. About 50 species, for example, are absent from the fossil record of the past 130,000 years.
Via Dr. Stefan Gruenwald
Scientists at Princeton University used off-the-shelf printing tools to create a functional ear that can 'hear' radio frequencies far beyond the range of normal human capability.
Creating organs using 3D printers is a recent advance; several groups have reported using the technology for this purpose in the past few months. But this is the first time that researchers have demonstrated that 3D printing is a convenient strategy to interweave tissue with electronics.
The technique allowed the researchers to combine the antenna electronics with tissue within the highly complex topology of a human ear. The researchers used an ordinary 3D printer to combine a matrix of hydrogel and calf cells with silver nanoparticles that form an antenna. The calf cells later develop into cartilage.
Manu Mannoor, a graduate student in McAlpine's lab and the paper's lead author, said that additive manufacturing opens new ways to think about the integration of electronics with biological tissue and makes possible the creation of true bionic organs in form and function. He said that it may be possible to integrate sensors into a variety of biological tissues, for example, to monitor stress on a patient's knee meniscus.
David Gracias, an associate professor at Johns Hopkins and co-author on the publication, said that bridging the divide between biology and electronics represents a formidable challenge that needs to be overcome to enable the creation of smart prostheses and implants.
"Biological structures are soft and squishy, composed mostly of water and organic molecules, while conventional electronic devices are hard and dry, composed mainly of metals, semiconductors and inorganic dielectrics," he said. "The differences in physical and chemical properties between these two material classes could not be any more pronounced."
The finished ear consists of a coiled antenna inside a cartilage structure. Two wires lead from the base of the ear and wind around a helical "cochlea" – the part of the ear that senses sound – which can connect to electrodes. Although McAlpine cautions that further work and extensive testing would need to be done before the technology could be used on a patient, he said the ear in principle could be used to restore or enhance human hearing. He said electrical signals produced by the ear could be connected to a patient's nerve endings, similar to a hearing aid. The current system receives radio waves, but he said the research team plans to incorporate other materials, such as pressure-sensitive electronic sensors, to enable the ear to register acoustic sounds.
In addition to McAlpine, Verma, Mannoor and Gracias the research team includes: Winston Soboyejo, a professor of mechanical and aerospace engineering at Princeton; Karen Malatesta, a faculty fellow in molecular biology at Princeton; Yong Lin Kong, a graduate student in mechanical and aerospace engineering at Princeton; and Teena James, a graduate student in chemical and biomolecular engineering at Johns Hopkins.
Via Dr. Stefan Gruenwald
In 2012, more than 3 million people had stents inserted in their coronary arteries. These tiny mesh tubes prop open blood vessels healing from procedures like a balloon angioplasty, which widens arteries blocked by clots or plaque deposits.
After about six months, most damaged arteries are healed and stay open on their own. The stent, however, is there for a lifetime. Most of the time, that's not a problem, says Patrick Bowen, a doctoral student studying materials science and engineering at Michigan Technological University.
The arterial wall heals in around the old stent with no ill effect. But the longer a stent is in the body, the greater the risk of late-stage side effects. For example, a permanent stent can cause intermittent inflammation and clotting at the implant site. In a small percentage of cases, the tiny metal segments that make up the stent can break and end up poking the arterial wall.
"When the stent stays in place 15, 20 or 25 years, you can see these side effects," says Bowen. "It's not uncommon to have a stent put in at age 60, and if you live to be 80, that's a long time for something to remain inert in your body."
That's why researchers are trying to develop a bioabsorbable stent, one that would gradually -- and harmlessly -- dissolve after the blood vessel is healed.
Many studies have investigated iron- and magnesium-based stents. However, iron is not promising: it rusts in the artery. Magnesium, on the other hand, dissolves too quickly. "We wondered, 'Isn't there something else?'" Bowen said. "And we thought, 'Why not zinc?'"
So they placed tiny zinc wires in the arteries of rats. The results were amazing. "The corrosion rate was exactly where it needed to be," Bowen said. The wires degraded at a rate just below 0.2 millimeters per year -- the "magic" value for bioabsorbable stents -- for the first three months.
After that, the corrosion accelerated, so the implant would not remain in the artery for too long. On top of that, the rats' arteries appeared healthy when the wires were removed, with tissue firmly grasping the implant.
"Plus, zinc reduces atherosclerosis," he added, referring to zinc's well-known ability to fight the development of plaque in the arteries. "How cool is that? A zinc stent might actually have health benefits."
There is one drawback. "A stent made of conventional zinc would not be strong enough to hold open a human artery," he said. "We need to beef it up, double the strength."
"The good news is that there are commercial zinc alloys that are up to three times stronger," Bowen said. "We know we can get there. We just don't want to ruin our corrosion behavior."
Via Dr. Stefan Gruenwald
Two children with an aggressive form of childhood leukemia had a complete remission of their disease—showing no evidence of cancer cells in their bodies—after treatment with a novel cell therapy that reprogrammed their immune cells to rapidly multiply and destroy leukemia cells. A research team from The Children’s Hospital of Philadelphia and the University of Pennsylvania published the case report of two pediatric patients Online First today in The New England Journal of Medicine. It will appear in the April 18 print issue.
The current study builds on Grupp’s ongoing collaboration with Penn Medicine scientists who originally developed the modified T cells as a treatment for B-cell leukemias. The Penn team reported on early successful results of a trial using this cell therapy in three adult chronic lymphocytic leukemia (CLL) patients in August of 2011. Two of those patients remain in remission more than 2½ years following their treatment, and as the Penn researchers reported in December 2012 at the annual meeting of the American Society of Hematology, seven out of ten adult patients treated at that point responded to the therapy. The team is led by the current study’s senior author, Carl H. June, M.D., the Richard W. Vague Professor in Immunotherapy in the department of Pathology and Laboratory Medicine and the Perelman School of Medicine at the University of Pennsylvania and director of Translational Research in Penn’s Abramson Cancer Center.
“We’re hopeful that our efforts to treat patients with these personalized cellular therapies will reduce or even replace the need for bone marrow transplants, which carry a high mortality risk and require long hospitalizations,” June said. “In the long run, if the treatment is effective in these late-stage patients, we would like to explore using it up front, and perhaps arrive at a point where leukemia can be treated without chemotherapy.”
The research team colleagues adapted the original CLL treatment to combat another B-cell leukemia: ALL, which is the most common childhood cancer. After decades of research, oncologists can currently cure 85 percent of children with ALL. Both children in the current study had a high-risk type of ALL that stubbornly resists conventional treatments.
The new study used a relatively new approach in cancer treatment: immunotherapy, which manipulates the immune system to increase its cancer-fighting capabilities. Here the researchers engineered T cells to selectively kill another type of immune cell called B cells, which had become cancerous.
The researchers removed some of each patient’s own T cells and modified them in the laboratory to create a type of CAR (chimeric antigen receptor) cell called a CTL019 cell. These cells are designed to attack a protein called CD19 that occurs only on the surface of certain B cells.
By creating an antibody that recognizes CD19 and then connecting that antibody to T cells, the researchers created in CTL019 cells a sort of guided missile that locks in on and kills B cells, thereby attacking B-cell leukemia. After being returned to the patient’s body, the CTL019 cells multiply a thousand times over and circulate throughout the body. Importantly, they persist for months afterward, guarding against a recurrence of this specific type of leukemia.
While the CTL019 cells eliminate leukemia, they also can generate an overactive immune response, called a cytokine release syndrome, involving dangerously high fever, low blood pressure, and other side effects. This complication was especially severe in Emily, and her hospital team needed to provide her with treatments that rapidly relieved the treatment-related symptoms by blunting the immune overresponse, while still preserving the modified T cells’ anti-leukemia activity.
“The comprehensive testing plan that we have put in place to study patients’ blood and bone marrow while they’re undergoing this therapy is allowing us to be able to follow how the T cells are behaving in patients in real time, and guides us to be able to design more detailed and specific experiments to answer critical questions that come up from our studies,” Kalos said.
The CTL019 therapy eliminates all B cells that carry the CD19 cell receptor: healthy cells as well as those with leukemia. Patients can live without B cells, although they require regular replacement infusions of immunoglobulin, which can be given at home, to perform the immune function normally provided by B cells.
The research team continues to refine their approach using this new technology and explore reasons why some patients may not respond to the therapy or may experience a recurrence of their disease. Grupp said the appearance of the CD19-negative leukemia cells in the second child may have resulted from her prior treatments. Unlike Emily, the second patient had received an umbilical cord cell transplant from a matched donor, so her engineered T cells were derived from her donor (transplanted) cells, with no additional side effects. Oncologists had previously treated her with blinatumomab, a monoclonal antibody, in hopes of fighting the cancer. The prior treatments may have selectively favored a population of CD19-negative T cells.
“The emergence of tumor cells that no longer contain the target protein suggests that in particular patients with high-risk ALL, we may need to broaden the treatment to include additional T cells that may go after additional targets,” added Grupp. “However, the initial results with this immune-based approach are encouraging, and may later even be developed into treatments for other types of cancer.”
Via Dr. Stefan Gruenwald
More than 1,700 American cities and towns – including Boston, New York, and Miami – are at greater risk from rising sea levels than previously feared, a new study has found.
By 2100, the future of at least part of these 1,700 locations will be "locked in" by greenhouse gas emissions built up in the atmosphere, theanalysis published in the Proceedings of the National Academy of Sciences on Monday found. For nearly 80 US cities, the watery future will come much sooner, within the next decade even.
The survey does not specify a date by which these cities, or parts of them, would actually fall under water. Instead, it specifies a "locked-in" date, by which time a future under water would be certain – a point of no return.
Because of the inertia built into the climate system, even if all carbon emissions stopped immediately, it would take some time for the related global temperature rises to ease off. That means the fate of some cities is already sealed, the study says.
"Even if we could just stop global emissions tomorrow on a dime, Fort Lauderdale, Miami Gardens, Hoboken, New Jersey will be under sea level," said Benjamin Strauss, a researcher at Climate Central, and author of the paper. Dramatic cuts in emissions – much greater than Barack Obama and other world leaders have so far agreed – could save nearly 1,000 of those towns, by averting the sea-level rise, the study found.
"Hundreds of American cities are already locked into watery futures and we are growing that group very rapidly," Strauss said. "We are locking in hundreds more as we continue to emit carbon into the atmosphere."
A recent study, also published in PNAS by the climate scientist Anders Levermann found each 1C rise in atmospheric warming would lead eventually to 2.3m of sea-level rise. The latest study takes those figures, and factors in the current rate of carbon emissions, as well as the best estimate of global temperature sensitivity to pollution.
For the study, a location was deemed "under threat" if 25% of its current population lives below the locked-in future high-tide level. Some 1,700 places are at risk in this definition. Even if bar is set higher, at 50% of the current population, 1,400 places would be under threat by 2100.
Via Dr. Stefan Gruenwald
It stands to reason that particle physics is about particles, and most people have a mental image of little billiard balls caroming around space. Yet the concept of “particle” falls apart on closer inspection. Many physicists think that particles are not things at all but excitations in a quantum field, the modern successor of classical fields such as the magnetic field. But fields, too, are paradoxical. If neither particles nor fields are fundamental, then what is? Some researchers think that the world, at root, does not consist of material things but of relations or of properties, such as mass, charge and spin.
Physicists routinely describe the universe as being made of tiny subatomic particles that push and pull on one another by means of force fields. They call their subject “particle physics” and their instruments “particle accelerators.” They hew to a Lego-like model of the world. But this view sweeps a little-known fact under the rug: the particle interpretation of quantum physics, as well as the field interpretation, stretches our conventional notions of “particle” and “field” to such an extent that ever more people think the world might be made of something else entirely.
The problem is not that physicists lack a valid theory of the subatomic realm. They do have one: it is called quantum field theory. Theorists developed it between the late 1920s and early 1950s by merging the earlier theory of quantum mechanics with Einstein's special theory of relativity. Quantum field theory provides the conceptual underpinnings of the Standard Model of particle physics, which describes the fundamental building blocks of matter and their interactions in one common framework. In terms of empirical precision, it is the most successful theory in the history of science. Physicists use it every day to calculate the aftermath of particle collisions, the synthesis of matter in the big bang, the extreme conditions inside atomic nuclei, and much besides.
So it may come as a surprise that physicists are not even sure what the theory says—what its “ontology,” or basic physical picture, is. This confusion is separate from the much discussed mysteries of quantum mechanics, such as whether a cat in a sealed box can be both alive and dead at the same time.
Via Dr. Stefan Gruenwald
In recent years, astronomers have detected some simple organic chemicals in the disks of material surrounding some stars. In our own Solar System, these seem to have undergone reactions that converted them into more complex molecules—some of them crucial for life—that have been found on meteorites. So, understanding the reactions that can take place in space can help provide an indication of the sorts of chemistry available to start life both here and around other stars.
Based on a publication in Nature Chemistry, it seems that the chemistry that can take place in the cold clouds of gas of space is much more complex than we had predicted. Reactions that would be impossible under normal circumstances—simply because there's not enough energy to push them forward—can take place in cold gasses due to quantum mechanical effects. That's because one of the reactants (a hydrogen nucleus) can undergo quantum tunneling between two reactants.
The key to understanding the work is the idea of activation energy. Many reactions that are energetically favorable (think burning wood) simply don't happen spontaneously. That's because the intermediate steps of the reaction are higher energy states. You need some additional energy (like a lit match) to push things over the activation energy barrier and get things to run downhill to the product state.
This, as you might imagine, is a problem in a cold gas cloud. With very little energy around, there's nothing available to hop a reaction over an activation energy barrier. On energetic considerations alone, there are some reactions that are simply impossible in that environment. And yet the authors of the new paper actually found that the reaction rate went up as the temperature went down.
The reaction the authors were looking at involved methanol, which has been found in gas clouds, and a hydroxyl radical. The latter is a water molecule with one of the hydrogens stripped away, leaving an unpaired electron. When these two molecules react, the favored outcome is to strip a hydrogen off the methanol, forming water and leaving a methoxy radical behind. Both hydroxyl and methoxy radicals have been detected in space.
Under normal circumstances, the intermediates of the reaction are energetic molecules with two oxygens bound to methanol's lone carbon. They require a fair bit of energy to create, which means there's a large activation energy to the reaction.
Once the temperature drops sufficiently, however, things start to change. At temperatures below 70K, rather than forming a covalently bonded intermediate, the two molecules can form a hydrogen bond. And at these temperatures, that bond will be relatively stable, keeping the two molecules in close proximity for extended periods of time. The proximity allows for quantum tunneling, in which small objects pass through a large energy barrier without occupying the intermediate, high energy states. In this case, one of the protons from the methanol simply tunnels over to the hydroxyl radical to form water, leaving a methoxy radical behind.
Methanol has four hydrogens, but the regular chemical reaction favors the transfer of specific ones when forming the water molecule. The authors found that the preference went away at low temperatures, confirming that something other than standard chemistry was going on here.
The fact that quantum tunneling allows reactions that would never take place in their own right is pretty impressive. But the results are also important because they give us a clearer picture of what's likely to be going on in the neighborhood of distant stars. Because of their distance, it's hard to detect anything other than raw materials around them. To infer the actual chemistry of the gas clouds, we have to look at the raw materials and the conditions, then figure out what reactions are likely to take place. By confirming that otherwise-impossible reactions can take place in these gas clouds, the authors have greatly expanded the range of chemistry we can expect to be taking place. And that can tell us something about the chemicals that are likely to be present in any planets formed under similar conditions.
Via Dr. Stefan Gruenwald
"Many of us tend to think of Antarctica as a sheet of solid snow and ice. But, in contrast with its peer to the north, the southern pole's ice sheet lies atop a rocky continent. What are its features, its mountains and valleys, plains and coastlines?
A new dataset from the British Antarctic Survey provides the most detailed map ever of the bedrock below, information scientists hope will enable them to better model the affects of climate change on the ice, whose melting will have an impact on climate the world over."
Via Seth Dixon
Chinese scientists trace the rare white coloration in Bengal tigers to a single change in a gene that affects a host of animals, including humans.
White tigers are a rare variant of the customary orange Bengal sub-species. Today, they are found exclusively in captive programmes where the limited numbers are interbred to maintain the distinctive fur color.
Shu-Jin Luo of Peking University and colleagues investigated the genetics of a family of tigers living in Chimelong Safari Park in Panyu, Guangzhou Province. This ambush of tigers included both white and orange individuals.
The study zeroed in on the pigment gene called SLC45A2, which has long been associated with the light colouration seen in some human populations, and in a range of other animals including horses, chickens, and fish.
The team identified a small alteration in the white-tiger version of SLC45A2 that appears to inhibit the production of red and yellow pigments. This change has no effect on the generation of black pigment - explaining why the whites still have their characteristic dark stripes.
A number of the white tigers found in zoos have health issues, such as eyesight problems and some deformities.
However, Luo and colleagues say these deficiencies are a consequence of inbreeding by humans and that the white coats are in no way indicative of a more general weakness in the Bengal variant.
Establishing this fact means that re-introducing them to the wild under a carefully managed conservation programme might be worth considering.
"The last known free-ranging white tiger was shot in 1958, before which sporadic sightings were made in India," the researchers write.
"Reasons for the extinction of wild white tigers were likely the same as those accounting for the dramatic decline in wild tigers in general: uncontrolled trophy hunting, habitat loss, and habitat fragmentation.
"However, the fact that many white tigers captured or shot in the wild were mature adults suggests that a white tiger in the wild is able to survive without its ﬁtness being substantially compromised."
Via Dr. Stefan Gruenwald
Scouring the caves of Southwest Oregon, scientists have made the incredible discovery of a fearsome apex predator with massive, sickle claws. No, it's not the Velociraptor fromJurassic Park: it's a large spider that is so unique scientists were forced to create a new taxonomic family for it. This is the first new spider family to be discovered in North America in over 130 years.
Via Dr. Stefan Gruenwald
In 8 May 1980, the World Health Organisation declared that “the world and its peoples are free from smallpox.” Through decades of intense vaccination, this once fatal disease had been wiped out. It was a singular victory and having won it, countries around the world discontinued the vaccination programmes. After all, why protect against a disease that no longer exists, except in a few isolated stocks?
Unfortunately, this is not a rhetorical question. The smallpox vaccine did more than protect against smallpox. It also reduced the risk of contracting a related illness called monkeypox, which produces the same combination of scabby bumps and fever. It’s milder than smallpox but it’s still a serious affliction. In Africa, where monkeypox originates from, it kills anywhere from 1-10% of those who are infected. And more and more people are becoming infected.
Anne Rimoin from the University of California, Los Angeles compared data on the virus in the Democratic Republic of Congo over the last three decades. She found that, during those years, monkeypox has become 20 times more common in humans. In one particular area, 72 people out of every million were infected each year between 1981 and 1986. Between 2005 and 2007, that figure rose to 1442 per million. Rimoin thinks that we eased up the pressure on smallpox vaccination too soon. Between 1981 and 1985, only 404 cases turned up in all of Africa, and simulations predicted that the disease was unlikely to spread too far in a human population before dying out. This was no public health threat. In 1986, even the monitoring programme was stopped. In 2005 however, Rimoin’s group, together with the DRC Ministry of Health and the World Health Organization set up a new round of monkeypox surveillance and they spent two years collecting data. Their research showed that the disease is gaining ground.
Rimoin found that monkeypox was disproportionately affecting children and almost all of those who fell sick were born after 1980, when the smallpox vaccination programme was halted in the DRC. The vaccine wasn’t a perfect defence against monkeypox but it was still around 85% effective. Among people who were born during the vaccination era, those who were immunised were 5 times less likely to develop monkeypox than their protected peers. And this protection is clearly long-lasting; even 25 years on, they could still ward off the related virus.
These figures are probably underestimates too. The region’s inconsistent healthcare isn’t exactly conducive to accurate disease monitoring and Rimoin says that her team had word of many more cases, but couldn’t always check them out because of their remote location.
Monkeypox is spread by animals including squirrels and, fairly obviously, monkeys. As humans encroach upon the DRC’s tropical rainforests, the risk of being exposed to an infected carrier grows. Indeed, Rimoin found that the odds of contracting monkeypox were higher for people living near forested areas, and for men. As civil strife continues to affect the DRC, locals are being forced to rely more on hunting to get enough food and that brings men in close contact with furry viral reservoirs.
It’s an emerging threat, but Rimoin isn’t calling for smallpox vaccination to resume. Doing so would be logistically difficult in an area where even collecting data can be fraught. It might be better to take a more targeted approach, vaccinating only health workers who treat infected patients, and people who come into frequent contact with animal carriers. It may also be worth educating local people about the dangers of handling carrier species and the benefits of isolating people who show the very obvious symptoms, until they can be treated.
But most importantly, Rimoin wants active surveillance in regions where the virus circulates, especially since there are still so many unknowns about the virus. We need to better understand how it moves from human to human (and from animal to human), how often it’s fatal, or what the complications are.
It’s a good opportunity to take action now, at a time when the monkeypox is still confined to specific areas. Things might not stay that way. In 2003, there was a bizarre outbreak in the United States, as rodents from Ghana brought the disease to American prairie dogs, who handed it over to humans. All sorts of rodents the world over might become reservoirs for the disease and Rimoin writes, “If monkeypox were to become established in a wildlife reservoir outside Africa, the public health setback would be difficult to reverse.”
Via Dr. Stefan Gruenwald
Unlike most exoplanet discoveries, which are inferred from analysis of data, the planets of the HR8799 system are directly visible from Earth. The planets were discovered in 2008 using the Keck and Gemini telescopes in Hawaii. The star HR8799, about 1.5 times the size of the sun and about five times brighter, lies 130 light years from Earth. Each of the star's four known planets is larger than any planet in our solar system. The star formed only 30 million years ago and is a variable star, meaning that its luminosity changes over a period of about half a day. By studying light reflected from planet HR8799c, astronomers have found water and carbon monoxide in its atmosphere.
Via Dr. Stefan Gruenwald
This is how Neptune's Great Dark Spot and rings may have looked in 1989 from a position just beneath Neptune's ring plane. The outermost Adams ring is near the top of the frame, and beneath that is the much broader and diffuse Lassell ring. Further in toward Neptune and abutting the Lassell ring is the thin LeVerrier ring, and beyond that is the diffuse Galle ring.
The Great Dark Spot is believed to be a storm similar to, but only half the size of, Jupiter's Great Red Spot. While Jupiter's Great Red Spot has been raging for at least 400 years, subsequent observations of Neptune's Great Dark Spot in 1994 by the Hubble Space Telescope revealed that this storm has since disappeared.
The Great Dark Spot was a very dynamic weather system, generating massive, white clouds similar to high-altitude cirrus clouds on Earth. Unlike cirrus clouds on Earth however, which are composed of crystals of water ice, Neptune's cirrus clouds are made up of crystals of frozen methane. Neptune's clouds are driven by winds of 1,200 mph, the fastest winds of any planet in the Solar System. How such high-velocity winds come to be on a planet so far from the Sun is still a mystery.
Via Dr. Stefan Gruenwald
A radical theory predicting the existence of “time crystals” — perpetual motion objects that break the symmetry of time — is being put to the test.
In February 2012, the Nobel Prize-winning physicist Frank Wilczek decided to go public with a strange and, he worried, somewhat embarrassing idea. Impossible as it seemed, Wilczek had developed an apparent proof of “time crystals” — physical structures that move in a repeating pattern, like minute hands rounding clocks, without expending energy or ever winding down. Unlike clocks or any other known objects, time crystals derive their movement not from stored energy but from a break in the symmetry of time, enabling a special form of perpetual motion.
“Most research in physics is continuations of things that have gone before,” said Wilczek, a professor at the Massachusetts Institute of Technology. This, he said, was “kind of outside the box."
The idea came to Wilczek while he was preparing a class lecture in 2010. “I was thinking about the classification of crystals, and then it just occurred to me that it’s natural to think about space and time together,” he said. “So if you think about crystals in space, it’s very natural also to think about the classification of crystalline behavior in time.”
When matter crystallizes, its atoms spontaneously organize themselves into the rows, columns and stacks of a three-dimensional lattice. An atom occupies each “lattice point,” but the balance of forces between the atoms prevents them from inhabiting the space between. Because the atoms suddenly have a discrete, rather than continuous, set of choices for where to exist, crystals are said to break the spatial symmetry of nature — the usual rule that all places in space are equivalent. But what about the temporal symmetry of nature — the rule that stable objects stay the same throughout time?
Via Dr. Stefan Gruenwald
A team of entomologists from the University of Illinois has found a possible link between the practice of feeding commercial honeybees high-fructose corn syrup and the collapse of honeybee colonies around the world.
Since approximately 2006, groups that manage commercial honeybee colonies have been reporting what has become known as colony collapse disorder—whole colonies of bees simply died, of no apparent cause. As time has passed, the disorder has been reported at sites all across the world, even as scientists have been racing to find the cause, and a possible cure. To date, most evidence has implicated pesticides used to kill other insects such as mites. In this new effort, the researchers have found evidence to suggest the real culprit might be high-fructose corn syrup, which beekeepers have been feeding bees as their natural staple, honey, has been taken away from them.
Commercial honeybee enterprises began feeding bees high-fructose corn syrup back in the 70's after research was conducted that indicated that doing so was safe. Since that time, new pesticides have been developed and put into use and over time it appears the bees' immunity response to such compounds may have become compromised.
The researchers aren't suggesting that high-fructose corn syrup is itself toxic to bees, instead, they say their findings indicate that by eating the replacement food instead of honey, the bees are not being exposed to other chemicals that help the bees fight off toxins, such as those found in pesticides.
Specifically, they found that when bees are exposed to the enzyme p-coumaric, their immune system appears stronger—it turns on detoxification genes. P-coumaric is found in pollen walls, not nectar, and makes its way into honey inadvertently via sticking to the legs of bees as they visit flowers. Similarly, the team discovered other compounds found in poplar sap that appear to do much the same thing. It all together adds up to a diet that helps bees fight off toxins, the researchers report. Taking away the honey to sell it, and feeding the bees high-fructose corn syrup instead, they claim, compromises their immune systems, making them more vulnerable to the toxins that are meant to kill other bugs.
Via Dr. Stefan Gruenwald