Some stars capture rogue planets.


New research suggests that billions of stars in our galaxy have captured rogue planets that once roamed interstellar space. The nomad worlds, which were kicked out of the star systems in which they formed, occasionally find a new home with a different sun. This finding could explain the existence of some planets that orbit surprisingly far from their stars, and even the existence of a double-planet system.

 

“Stars trade planets just like baseball teams trade players,” said Hagai Perets of the Harvard-Smithsonian Center for Astrophysics.

The study, co-authored by Perets and Thijs Kouwenhoven of Peking University, China, will appear in the April 20th issue of The Astrophysical Journal.

To reach their conclusion, Perets and Kouwenhoven simulated young star clusterscontaining free-floating planets. They found that if the number of rogue planets equaled the number of stars, then 3 to 6 percent of the stars would grab a planet over time. The more massive a star, the more likely it is to snag a planet drifting by.

They studied young star clusters because capture is more likely when stars and free-floating planets are crowded together in a small space. Over time, the clusters disperse due to close interactions between their stars, so any planet-star encounters have to happen early in the cluster’s history.

Rogue planets are a natural consequence of star formationNewborn star systems often contain multiple planets. If two planets interact, one can be ejected and become an interstellar traveler. If it later encounters a different star moving in the same direction at the same speed, it can hitch a ride.

A captured planet tends to end up hundreds or thousands of times farther from its star than Earth is from the Sun. It’s also likely to have a orbit that’s tilted relative to any native planets, and may even revolve around its star backward.

Astronomers haven’t detected any clear-cut cases of captured planets yet. Imposters can be difficult to rule out. Gravitational interactions within a planetary system can throw a planet into a wide, tilted orbit that mimics the signature of a captured world.

Finding a planet in a distant orbit around a low-mass star would be a good sign of capture, because the star’s disk wouldn’t have had enough material to form the planet so far out.

The best evidence to date in support of planetary capture comes from the European Southern Observatory, which announced in 2006 the discovery of two planets (weighing 14 and 7 times Jupiter) orbiting each other without a star.

“The rogue double-planet system is the closest thing we have to a ‘smoking gun’ right now,” said Perets. “To get more proof, we’ll have to build up statistics by studying a lot of planetary systems.”

Could our solar system harbor an alien world far beyond Pluto? Astronomers have looked, and haven’t found anything yet.

“There’s no evidence that the Sun captured a planet,” said Perets. “We can rule out large planets. But there’s a non-zero chance that a small world might lurk on the fringes of our solar system.”

Source:  Harvard-Smithsonian Centre for Astrophysics

 

‘Sabpab’ Trojan seeks out Mac OS X.


Three compelling reasons that Mac loyalists say justify their love for Macs have been that Macs are 1) the prettiest computers around (2) ideal for any new-age brain that prefers visually rich knowledge work and (3) their systems are far safer than Windows-based PCs, which have been sneered at as malware magnets. This year, life has got Mac-Liter as now they only have to brandish two good reasons. Researchers at major security companies such as Kaspersky Lab and Sophos say that the Mac has yet another Trojan attacker,following Flashback, that can steal information from a system once infected.

 

The Sabpab Trojan represents a second round of malware targeted at users of Macmachines. The earlier Flashback, according to some reports, may have succeeded in infecting as many as 600,000 Mac systems. Flashback was designed to get installed on as many machines as possible so that its operators could profit from scams such as click fraud. Apple resolved the mess by issuing a patch while other companies offered up their own clean-up tools for detection and removal. Observers expressed concerns over how Apple was late in presenting its own tool to remove the Flashback malware, while, outside Apple, other firms had issued their free offerings.

With this latest Trojan, the exploiters are able to grab screenshots from infected Macs, upload and download files, and execute commands remotely. According to reports, the malware takes advantage of the same security flaw in Java that Flashback exploited.

Two unsettling features of the new malware are that this is a back-door Trojan that does not require any user interaction to infect and, according to Costin Rau, a security expert with Kaspersky, the Trojan is an advance persistent threat (APT) attack in an active stage.

The definition of APT varies from one security group to another, but it is not trivial. The U.S. National Institute of Standards and Technology (NIST) defines APT as “an adversary that possesses sophisticated levels of expertise and significant resources which allow it to create opportunities to achieve its objectives” using multiple attack vectors. Mandiant, an information security company, calls the APT a sophisticated and organized cyber attack to access and steal information from compromised computers. ”The attacks used by the APT intruders are not very different from any other intruder,” says the company; the difference is in the intruder’s perseverance and resources. “They have malicious code (malware) that circumvents common safeguards such as anti-virus and they tend to generate more activity than wanton ‘drive by hacks’ on the Internet.”

The APT threat is using IP addresses that have been known to wage similar attacks on Windows users, according to Kaspersky.

Sophos sources, meanwhile, say that the “Sabpab” is not believed to be as widespread as Flashback, but it is yet another wakeup call for Mac users that security is no longer a non-issue. Security on the Mac has become a key issue.

Soure: physics.org

 

Retroreflector transmits light with negligible power consumption.


In free-space optical communications (FSO), data is wirelessly transmitted by light propagating through open space. Among their applications, FSO systems are used for communications between spacecraft and have the potential to serve as the “last mile” for fiber optics broadband services. However, one challenge they face is that the light sources used to encode the data require power, and a power supply is often limited. Devices that reflect light, called corner cube retroreflectors (CCRs), can overcome this problem because they can transmit data without their own light source, simply by reflecting incident light from a base station.

 

Although CCRs were introduced more than 10 years ago as a solution for FSO systems, they face their own challenges, most notably the need for a high voltage. In a new study, a team of researchers from Seoul, South Korea, has improved the CCR design so that it operates with an ultra-low voltage and negligible power consumption. The new design, which is based on MEMS technology, could make the devices more attractive for FSO systems.

As the researchers explain in their study, CCRs work by digitally modulating incident laser light. The device reflects laser light coming from the base station back toward the source in the “on” state, and scatters the light away from the source in the “off” state. By quickly switching between states, the CCR can transmit data at high speeds.

The CCR device itself consists of three mirrors: two vertical mirrors form a cross on top of a horizontal mirror, resulting in four concave corners. The alignment of the mirrors is essential, since perfect alignment constitutes the “on” state to reflect light. Misalignment occurs when a piezoelectric cantilever causes the horizontal mirror to lift a few micrometers above the substrate like a seesaw, which causes incident light to scatter.

 

In previous designs, the piezoelectric cantilever required high voltages to move the mirror, but the new design can work with ultra-low voltages due to improved mirror alignment. To do this, the researchers added two supporting cantilevers in addition to the actuating cantilever, which helps improve the initial alignment of the horizontal mirror. A simplified fabrication process also improves the alignment and flatness of the mirrors.

“The developed CCR is the first device fabricated by combining a cross-shaped vertical silicon mirror and a piezoelectrically actuated horizontal mirror,” Jae Park, Professor of Electrical Engineering at Kwangwoon University, told Phys.org. “There are two significant advantages in its fabrication. Firstly, the cross-shaped vertical mirror was simply fabricated by using a double-SOI wafer and anisotropic KOH etching technique. This method provides good surface roughness and accurate angular alignment of reflective surfaces in the vertical mirror with mass productivity. Secondly, microfabricated piezoelectric cantilever actuator was applied to actuate the horizontal mirror. The piezoelectric cantilever provides larger angular displacement at a lower induced voltage than a conventional electrostatic actuator without power consumption.”

In addition to their ability to operate with a negligible power consumption, the new CCRs can also be produced with low-cost methods and can be integrated with sensors and CMOS circuits. The researchers noted that the communication distance is still limited, since the horizontal mirror has some curvature that leads to some misalignment. They hope to improve the flatness of the horizontal mirror in the future.

“One of the most promising applications is optical sensor networks (OSN) using direct optical links,” Park said. “Use of direct optical links improves network security of OSNs significantly over RFSNs (radio frequency sensor networks). The improved network security is one of the critical elements that make OSNs ideal, for example, to military applications. We can also consider the applications of broadcast and scanning networks. A light ray from the base station is directly scanned using a galvanometer scanner, and a CMOS imager is utilized for space-division multiple access (SDMA) with CCR sensor nodes distributed in the broadcast area. The SDMA-based broadcast and scanning network can also be considerable.”

Source:  Physics.Org 

 

Physicists Create First Long-Distance Quantum Link.


For more than a decade, physicists have been developing quantum-mechanical methods to pass secret messages without fear that they could be intercepted. But they still haven’t created a true quantum network—the fully quantum-mechanical analog to an ordinary telecommunications network in which an uncrackable connection can be forged between any two stations or “nodes” in a network. Now, a team of researchers in Germany has built the first true quantum link using two widely separated atoms. A complete network could be constructed by combining many such links, the researchers say.

“These results are a remarkable achievement,” says Andrew Shields, an applied physicist and assistant managing director at Toshiba Research Europe Ltd. in Cambridge, U.K., who was not involved in the work. “In the past, we have built networks that can communicate quantum information, but convert it into classical form at the network switching points. [The researchers] report preliminary experiments towards forming a network in which the information remains in quantum form.”

Quantum communication schemes generally take advantage of the fact that, according to quantum theory, it’s impossible to measure the condition or “state” of a quantum particle without disturbing the particle. For example, suppose Alice wants to send Bob a secret message. She can do the encrypting in a traditional way, by writing out the message in the form of a long binary number and zippering it together in a certain mathematical way with a “key,” another long stream of random 0s and 1s. Bob can then use the same key to unscramble the message.

But first, Alice must send Bob the key without letting anybody else see it. She can do that if she encodes the key in single particles of light, or photons. Details vary, but schemes generally exploit the fact that an eavesdropper, Eve, cannot measure the individual photons without altering their state in some way that Alice and Bob can detect by comparing notes before Alice encodes and sends her message. Such “quantum key distribution” has already been demonstrated in networks, such as a large six-node network in Vienna in 2008, and various companies offer quantum key distribution devices.

Such schemes suffer a significant limitation, however. Although the key is passed from node to node in a quantum fashion, it must be read out and regenerated at each node in the network, leaving the nodes vulnerable to hacking. So physicists would like to make the nodes of the network themselves fully quantum mechanical—say, by forming them out of individual atoms.

According to quantum mechanics, an atom can have only certain discrete amounts of energy depending on how its innards are gyrating. Bizarrely, an atom can also be in two different energy states—call them 0 and 1—at once, although that uncertain two-states-at-once condition “collapses” into one state or the other as soon as the atom is measured. “Entanglement” takes weirdness to its absurd extreme. Two atoms can be entangled so that both are in an uncertain two-ways-at-once state, but their states are perfectly correlated. For example, if Alice and Bob share a pair of entangled atoms and she measures hers and finds it in the 1 state, then she’ll know that Bob is sure to find his in the 1 state, too, even before he measures it.

Obviously, Alice and Bob can generate a shared random key by simply entangling and measuring their atoms again and again. Crucially, if entanglement can be extended to a third atom held by Charlotte, then Alice and Charlotte can share a key. In that case, if Eve then tries to detect the key by surreptitiously measuring Bob’s atom, she’ll mess up the correlations between Alice’s and Charlotte’s atoms in a way that will reveal her presence, making the truly quantum network unhackable, at least in principle.

But first, physicists must entangle widely separated atoms. Now, Stephan Ritter of the Max Planck Institute of Quantum Optics in Garching, Germany, and colleagues have done just that, entangling two atoms in separate labs on opposite sides of the street, as they report online today in Nature.

As simple as this may sound, the researchers still needed a complete lab room full of lasers, optical elements, and other equipment for each node. Each atom sat between two highly reflective mirrors 0.5 mm apart, which form an “optical cavity.” By applying an external laser to atom A, Ritter’s team caused a photon emitted by that atom to escape from its cavity and travel through a 60-meter-long optical fiber to the cavity across the street. When the photon was absorbed by atom B, the original quantum information from the first atom was transferred to the second. By starting with just the right state of the first atom, the researchers could entangle the two atoms. According to the researchers, the entanglement could in principle be extended to a third atom, which makes the system scalable to more than two nodes.

“Every experimental step had to be just right to make this work,” says Ritter, who works in the group of Gerhard Rempe. “Take, for example, the optical cavity. All physicists agree that atoms and photons are great stuff for building a quantum network, but in free space they hardly interact. We needed to develop the cavity for that.”

“This is a very important advance,” says Toshiba’s Shields, because it would enable technologists to share quantum keys on networks where the intermediate nodes can’t be trusted, and it could also lead to more complex multiparty communication protocols based on distributed entanglement. “However,” Shields cautions, “there is still a great deal of work to be done before the technology is practical.” Miniaturization of the components that constitute one node will no doubt be on the researchers’ wish list.

Source: ScienceNOW

 

 

 

Physicists Discover New Type of Particle–Sort Of.


In 1937, after the rise of quantum mechanics, Ettore Majorana, an Italian theoretical physicist, realized that the new physics implied the existence of a novel type of particles, now called Majorana fermions. After a 75-year hunt, researchers have now spotted the first solid evidence of their existence. And their discovery could hold the key to finally creating workable quantum computers .

Prior to Majorana’s work, Austrian physicist Erwin Schrödinger came up with an equation that describes how quantum particles behave and interact. Paul Dirac, an English physicist, tweaked that equation to apply it to fermions, such as electrons, moving at near-light speed. That work tied together quantum mechanics and Einstein’s special theory of relativity. It also implied the existence of antimatter, where every particle has an antimatter counterpart—such as electrons and positrons—and that the two would annihilate each other if they ever met. Dirac’s work suggested that some particles, such as photons, could serve as their own antiparticles. But fermions weren’t thought to be among them. It was Majorana’s manipulations of Dirac’s equations that suggested the possible existence of a new type of fermion that could serve as its own antiparticle.

At the time, Majorana thought a type of neutrino, an electrically neutral particle with a tiny mass, might fit the bill for his proposed particle. And scientists continue to search for evidence that neutrinos are or are not their own antiparticles. But decades after Majorana’s proposal, theoretical physicists realized that the coordinated motion of large numbers of electrons in electronic devices might mimic the behavior of Majorana fermions. These collective motions aren’t elementary bits of matter the way electrons and neutrinos are. Rather, they are “quasiparticles.” But they should behave much as would elementary particles of the same type. It is the signs of these quasiparticles that researchers led by physicist Leo Kouwenhoven and colleagues at Delft University of Technology report online today in Science.

To spot their quarry, Kouwenhoven’s group created specially designed transistors. In standard transistors, applying a voltage to a metal electrode called a gate turns on the flow of current through a semiconductor between two other metal electrodes. Previous theoretical predictions suggested that if one of the secondary electrodes was a superconductor, and the current was allowed to flow through a special semiconductor nanowire under a magnetic field, the combination would force electrons in the nanowire to behave collectively as if Majorana fermions were present at opposite ends of the wire. Theory further offered that if researchers tried to send an electric current from the normal electrode to the superconducting electrode without the magnetic field turned on, the electrons trying to make the journey would essentially bounce off the superconductor, so no current would be detected at the superconducting electrode. But if the magnetic field is turned on, this would trigger the presence of Majorana fermions, which would enable electrons to enter the superconductor, and that would produce a jump in the current.

This current spike is what Kouwenhoven’s team found. When the researchers then removed any one of the conditions needed to induce Majorana fermions—such as the magnetic field, or replacing the superconducting electrode with another metal electrode—the current spike at the second electrode vanished.

The results don’t provide a direct detection of Majorana fermions. But the Dutch team did a “very compelling” job of eliminating all other possible explanations, says Jason Alicea, a theoretical physicist at the University of California, Irvine. However, the study doesn’t completely nail the case for the presence of Majorana fermions, he cautions. The current spike is only 5% of what theory predicts. But that may be because the equipment used to chill the experimental setup must be improved to get closer to absolute zero, where the signal for Majoranas should be the strongest.

If Majoranas are confirmed, they are expected to have properties that make them ideal for constructing a quantum computer. When you move two Majorana fermions with respect to one another, they essentially “remember” their former position, a property that could be used to encode data at the quantum level. Kouwenhoven’s group hasn’t spotted that signature yet, but they’re on the hunt now.

Source: ScienceNOW

 

Hot new manufacturing tool: A temperature-controlled microbe.


Many manufacturing processes rely on microorganisms to perform tricky chemical transformations or make substances from simple starting materials. The authors of a study appearing in mBio, the online open-access journal of the American Society for Microbiology, on April 17 have found a way to control a heat-loving microbe with a temperature switch: it makes a product at low temperatures but not at high temperatures. The innovation could make it easier to use microorganisms as miniature factories for the production of needed materials like biofuels.

 

This is the first time a targeted modification of a hyperthermophile (heat-loving microorganism) has been accomplished, say the authors, providing a new perspective on engineering microorganisms for bioproduct and biofuel formation.

Originally isolated from hot marine sediments, the hyperthermophile Pyrococcus furiosus grows best at temperatures around 100ºC (212ºF). P. furiosus is an archaeon, single-celled organisms that bear a resemblance to bacteria, but they excel at carrying out many processes that bacteria cannot accomplish. Like other hyperthermophiles, P. furiosus‘ enzymes are stable at the high temperatures that facilitate many industrial processes, making it a well-used tool in biotechnology and manufacturing. But not all products can be made at high heat. Some enzymes will only work at lower temperatures.

In the study in mBio®, the authors inserted a gene from another organism into P. furiosus and coaxed it to use that gene to make a new product by simply lowering the temperature. The donor organism, Caldicellulosiruptor bescii, prefers to grow at a relatively cool 78ºC, so the protein product of its gene, lactate dehydrogenase, is most stable at that comparatively low temperature.

The authors of the study inserted the lactate dehyrogenase gene into a strategic spot, right next to a cold shock promoter that “turns on” the genes around it when P. furiosusis out in the cold at 72ºC. This essentially gives scientists a switch for controlling lactate production: put the organism at 72ºC to turn on lactate production, restore it to 100ºC to turn it off, thus preventing the need for chemical inducers. What’s more, since P. furiosus is mostly shut down at these lower temperatures, making the new product doesn’t interfere with its metabolism, or vice-versa.

The lead author on the study, Michael Adams of the Department of Biochemistry & Molecular Biology at the University of Georgia, explains that this is the key benefit of this system: although P. furiosus now makes the enzyme that carries out the process, at these lower temperatures the organism’s other metabolic processes don’t get in the way.

“The hyperthermophile is essentially the bioreactor that contains the foreign enzymes,” says Adams. P. furiosus just supplies cofactors and a cytoplasmic environment for the highly active foreign enzymes, according to Adams. This makes for a cleaner, more controllable reaction.

Source:American Society for Microbiology

 

 

 

Nano-Syringe Delivers Combination, Targeted Brain Cancer Therapy.


Nanomedicine researchers at the Methodist Neurological Institute and Rice University have developed a way to selectively kill brain cancer cells by using a tiny syringe to deliver a combination of chemotherapy drugs directly into the cells. These findings will be published in the April 24 issue of the American Chemical Society journal ACS Nano.


Patients with glioblastoma multiforme (GBM), the most common and aggressive malignant primary brain tumor, typically have a prognosis of 14-month median survival time despite medical interventions, which currently include surgery, chemotherapy and radiation.

The Rice-Methodist group developed the hydrophilic carbon cluster (HCC) antibody drug enhancement system (HADES), named after the Greek god of the underworld. Through a 20-nanometer syringe, which is 2 million times smaller than a coffee mug, this nanovector successfully delivered a combination of three chemotherapy drugs into GBM cells in vivo, resulting in a high kill rate.

“Without our nano-delivery system, we know that current drug delivery would be highly toxic to patients if we tried to deliver all three of these drugs at once,” said David Baskin, M.D., neurosurgeon at the Methodist Neurological Institute, who began his nanomedicine research in 2004 with the late Nobel laureate and Rice chemist Richard Smalley. “But delivered in combination using these nano-syringes, our research demonstrated extreme lethality, with at least a three-fold increase in the number of dead cancer cells following treatment. The nano-syringes selectively deliver these drugs only to cancer cells, and appear not to be toxic to normal neurons and other non-cancerous brain cells.”

HCCs are nanovectors with protective antioxidant properties, capable of transporting and delivering drugs and bioactive molecules. In order to bring the drug carriers close enough to the cancer cells and successfully deliver the chemotherapy combination, three different antibodies were combined with the HCC to allow the nanoparticle to stick to the cell membrane. The drugs stayed inside the HCC until it attached to the cell membrane. Once binding occurred, the drugs were released into the fatty (lipid) environment in the membrane. The chemical properties of the chemotherapy drugs inside the HCC are such that they prefer to accumulate in areas with high concentrations of lipids and avoid areas with high water content, such as the extracellular space.

“A new and exciting advance is that now we have a carrier with protective properties, unlike previous nanotubes which were shown to be toxic,” said Martyn Sharpe, the paper’s lead author and a scientist with the Methodist NI’s department of neurosurgery. “Some of the chemotherapy agents used in this research traditionally perform poorly with GBMs. Now that we’ve shown a successful kill rate of these cells in vivo, we’re looking at treating human tumors that will be grown in immune-compromised mice models.”

As personalized medicine continues to evolve, Baskin says this research could also be significant for other forms of cancer, including breast and head and neck cancers.

The paper represents an important collaboration between the laboratories of Baskin at Methodist, and James Tour, Ph.D. with Rice University’s Smalley Institute for Nanoscale Science. Further work developing this system and expanding its utility is under way with continued collaboration between these two research groups.

 

Source: ScienceDaily

 

World Hemophilia Day.April 17.


PRESS RELEASE

World Hemophilia Day –

Access to Diagnosis and Treatment Limited for Most People with Bleeding

Disorders: Help Close the Gap

(Montreal, April 16, 2012): An estimated one in 1000 women and men has a bleeding

disorder. However, 75 per cent still receive very inadequate treatment or no treatment at

all. What will it take to Close the Gap?

On World Hemophilia Day 2012, the global bleeding disorders community will spread

the message to “Close the Gap” in care around the world. Together, we can work

toward a day when treatment will be available for all globally.

Many are unaware that if untreated, people with severe hemophilia will face pain,

stigma, disability, and might not survive to adulthood. It is also fairly unknown that

postpartum hemorrhage is the main cause of maternal death and long-term disability for

women around the world.

“The reality is that most people with hemophilia or other bleeding disorders do not

receive adequate diagnosis, treatment and management for their conditions,” said

Mark Skinner, World Federation of Hemophilia (WFH) president. “This is important

whether good treatment is already established but needs to be protected, or where

treatment needs to be improved.”

The WFH launched an awareness campaign this year, through social media, that aims to

inform the global community about bleeding disorders and the need for better access to

treatment. On World Hemophilia Day, April 17, hemophilia organizations and

hemophilia treatment centres around the world are participating by organizing local

events, wearing red, and going online to increase awareness of hemophilia and other

bleeding disorders.

To learn more about what the global community is doing to “Close the Gap,” visit

http://www.wfh.org/facebook or follow WFH on Twitter or YouTube.

World Hemophilia Day is supported with funding by Baxter, Bayer, Biogen Idec

Hemophilia, CSL Behring, Inspiration Biopharmaceuticals and Novo Nordisk.

Join the international bleeding disorders community on April 17 to mark World

Hemophilia Day. Help us “Close the Gap.” About hemophilia and other bleeding disorders

Hemophilia, von Willebrand disease, inherited platelet disorders, and other factor

deficiencies are lifelong bleeding disorders that prevent blood from clotting properly.

People with bleeding disorders do not have enough of a particular clotting factor, a

protein in blood that controls bleeding, or else it does not work properly. The severity of

a person’s bleeding disorder usually depends on the amount of clotting factor that is

missing or not functioning. People with hemophilia can experience uncontrolled internal

bleeding that can result from a seemingly minor injury. Bleeding into joints and muscles

causes severe pain and disability while bleeding into major organs, such as the brain,

can cause death.

About the World Federation of Hemophilia (WFH)

For 50 years, the World Federation of Hemophilia, an international not-for-profit

organization has worked to improve the lives of people with hemophilia and other

inherited bleeding disorders. Established in 1963, it is a global network of patient

organizations in 118 countries and has official recognition from the World Health

Organization. Visit WFH online at http://www.wfh.org.

For more information please contact:

Sarah Ford

1 514 394 2822

sford@wfh.org

Source: www.wfh.org

 

 

 

 

Egg-laying beginning of the end for dinosaurs.


Daryl Codron explains what this means for biodiversity: “The consensus among researchers is that animals of particular body sizes occupy particular niches. In the case of the dinosaurs, this would mean that a single species occupied the majority of the ecological niches while mammals occupied these through numerous species of different sizes.” Accordingly, the research results reveal that dinosaurs of a small and medium body size were represented with far fewer individual species than was the case in mammals – because their niches were occupied by the young of larger species. “An overview of the body sizes of all dinosaur species – including those of birds, which are also dinosaurs after all – reveals that few species existed with adults weighing between two and sixty kilograms,” specifies Codron. And Marcus Clauss sums up the consequences of this demonstrated by the researchers using computer simulations: “Firstly, this absence of small and medium-sized species was due to the competition among the dinosaurs; in mammals, there was no such gap. Secondly, in the presence of large dinosaurs and the ubiquitous competition from their young, mammals did not develop large species themselves.” The third insight that the computer simulation illustrates concerns small dinosaurs: They were in competition both among their own ranks and with small mammals. And this increased pressure brought the small dinosaurs either to the brink of extinction or forced them to conquer new niches. The latter enabled them to guarantee their survival up to the present day, as Codron concludes, since “back then, they had to take to the air as birds”.

 

The dinosaurs’ supremacy as the largest land animals remained intact for 150 million years. The mass extinction at the Cretaceous-Tertiary boundary, however, spelled trouble as the species gap in the medium size range turned out to be disastrous for them. According to the current level of knowledge, all the larger animals with a body weight from approximately ten to 25 kilos died out. Mammals had many species below this threshold, from which larger species were able to develop after the calamity and occupy the empty niches again. The dinosaurs, however, lacked the species that would have been able to reoccupy the vacant niches. That was their undoing.

Source:University of Zurich

 

Brain Cancer Vaccine Proves Effective, Study Suggests.


A new brain cancer vaccine tailored to individual patients by using material from their own tumors has proven effective in a multicenter phase 2 clinical trial at extending their lives by several months or longer. The patients suffered from recurrent glioblastoma multiforme — which kills thousands of Americans every year.


These results, announced April 17 at the American Association of Neurological Surgeons (AANS) meeting in Miami, compared the effectiveness of the vaccine for more than 40 patients treated at UCSF’s Helen Diller Family Comprehensive Cancer Center, at the Seidman Cancer Center at University Hospitals Case Medical Center in Cleveland and at New York-Presbyterian Hospital/Columbia University Medical Center in New York City.

The trial found the vaccine could extend survival for the patients by several months when compared to 80 other patients who were treated at the same hospitals and received standard therapy — 47 weeks compared to 32 weeks. Several of the patients who received the cancer vaccine have survived for more than a year.

“These results are provocative,” said UCSF neurosurgeon Andrew Parsa, MD, PhD, who led the research. “They suggest that doctors may be able to extend survival even longer by combining the vaccine with other drugs that enhance this immune response.”

The next step, he said, will be a more extensive, randomized clinical trial to look at the effectiveness of the vaccine combined with the drug Avastin, a standard therapy for this type of cancer, compared to the effectiveness of Avastin alone. Those trials, to be run by the National Cancer Institute, will begin enrolling patients later this year.

Clinical Trial Paid for In Part by Patient Groups

The UCSF Department of Neurological Surgery is ranked by U.S. News & World Report as one of the top departments in the world. Its doctors perform more than 1,100 neurosurgeries a year to remove brain tumors, and in the last 30 years, this work has helped to build one of the most extensive brain tumor repositories in the United States, with tissue samples collected from thousands of people with cancer.

Part of the funding for the Phase 2 trial came though a $1.5 million-a-year grant to UCSF from the National Cancer Institute — called Brain Tumor SPORE (Specialized Program of Research Excellence). Now in its 10th year, the grant aims to translate basic laboratory and clinical discoveries into optimal ways of delivering treatment and monitoring a patient’s progress.

The Phase 2 trial also was partially paid for with funds provided by the patient advocacy groups American Brain Tumor Association, Accelerate Brain Cancer Cure and the National Brain Tumor Society — groups that Parsa credits with spearheading the effort.

“It never would have happened without them,” Parsa said. “Patient advocacy groups are an important component of how we inform patients about this disease. These groups are also increasingly critical to funding translational research, which bridges the gap between the laboratory and the clinic.”

Parsa has not received any personal financial support, consulting fees, or travel expense reimbursement for this work from Agenus, Inc., the biotech company that makes the new vaccine. Neither Parsa nor UCSF have any financial interest in the company.

Background on Glioblastoma and Cancer Vaccines

Some 17,000 Americans are diagnosed with glioblastoma every year, and only 2 percent of them survive longer than five years — even with treatment. The cancer always recurs, he added, and it is only a matter of when.

Glioblastoma treatment generally begins with a surgical resection, in which neurosurgeons remove the cancerous tissue from the brain. The surgery usually is followed by radiation therapy and then chemotherapy to kill any remaining cancer cells. Many people undergo treatment only to have the cancer return a few months later, at which point doctors may operate again, followed by more chemotherapy.

Cancer vaccines are a relatively new approach that has appeared in the last decade. In 2010, the U.S. Food and Drug Administration approved the first therapeutic cancer vaccine for prostate cancer, and several more cancer vaccines are in clinical trial. The basic concept is similar to a vaccine for a disease like measles or mumps: an injection in the arm induces an immune response that helps the body fight the particular pathogen — or in this case, the cancer. An effective immune response would then shrink tumors and extend lives.

In the past, vaccines did not seem to work because they did not produce effective immune responses: either they did not kill all of the tumor cells or they worked on some patients but not on others. Work on the new vaccine began after several brain cancer advocacy groups pooled their resources several years ago and approached doctors at leading cancer centers, requesting proposals for new ways to fight recurrent glioblastoma. Parsa and his colleagues proposed a new type of cancer vaccine based on tiny molecular bundles called heat shock proteins.

These molecules are recovered from tumors surgically removed from patients in the trial. Agenus, Inc., prepares a vaccine specific for each patient and ships the vaccine back to the doctors who then inject it into the patient’s arm several times over the course of the year.

The presentation, “A Phase 2 Multicenter Trial of Autologous Heat Shock Proteinpeptide Vaccine (HSPPC-96) for Recurrent Glioblastoma Multiforme (GBM) Patients Shows Improved Survival Compared to a Contemporary Cohort Controlled for Age, KPS and Extent of Resection” by Andrew Thomas Parsa, Courtney Crane, Seunggu Han, Valerie Kivett; Anne Fedoroff, Nicholas Butowski, Susan Chang, Michael Prados, Jennifer Clarke, Mitchel Berger, Michael McDermott, Manish Aghi, Andrew Sloan, Jeffrey Bruce was delivered on April 17.

 

Source: Scinece daily