Science & Technology


Planet-forming lifeline discovered in binary star system

double star system GG Tauri-A
© Credit: ESO/L. Calçada
This artist's impression shows the dust and gas around the double star system GG Tauri-A. Researchers using ALMA have detected gas in the region between two discs in this binary system. This may allow planets to form in the gravitationally perturbed environment of the binary. Half of Sun-like stars are born in binary systems, meaning that these findings will have major consequences for the hunt for exoplanets.
Scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) have detected a streamer of dust and gas flowing from a massive outer disk toward the inner reaches of a binary star system. This never-before-seen feature may be responsible for sustaining a second, smaller disk of planet-forming material that otherwise would have disappeared long ago.

A research group led by Anne Dutrey from the Laboratory of Astrophysics of Bordeaux, France, and the National Centre for Scientific Research (CNRS) observed the distribution of dust and gas in a binary star system called GG Tau-A. It was recently discovered that one of GG Tau-A's components is itself a double star. This object is only a few million years old and lies approximately 460 light-years from Earth in the constellation Taurus.

Like a wheel in a wheel, GG Tau-A contains a large, outer disk encircling the entire system as well as an inner disk around the main central star. This second inner disk has a mass roughly equivalent to that of Jupiter. Its presence has been an intriguing mystery for astronomers since it is losing material to its central star at a rate that should have depleted it long ago.

While observing these structures with ALMA, the team made the exciting discovery of gas clumps in the region between the two disks. The new observations suggest that material is being transferred from the outer to the inner disk, creating a sustaining lifeline between the two.

Comment: see also:

New study supports binary star system hypothesis

evidence that Earth like-worlds can form in two star solar systems

astrophysicists find wide binary stars wreak havoc in planetary systems


What happens to a dead body in the ocean?

© VENUS/Gail Anderson and Lynne Bell
Deep-sea scavengers made quick work of this pig's carcass.
When a dead body decomposes in the ocean, scientists know little about what happens to it. To find out, some researchers performed an unusual experiment that involved dropping pig carcasses into the sea and watching them on video.

Lots of human bodies end up in the sea, whether due to accidents, suicides or from being intentionally dumped there, but nobody really knows what happens to them, said Gail Anderson, a forensic entomologist at Simon Fraser University in Canada who led the unusual study.

Anderson and her team got a chance to find out, using the Victoria Experimental Network Under the Sea (VENUS), an underwater laboratory that allows scientists to take video and other measurements via the Internet. With that equipment, all they needed was a body.

"Pigs are the best models for humans," Anderson told Live Science. They're roughly the right size for a human body; they have the same kind of gut bacteria, and they're relatively hairless, she said.

In the study, published Oct. 20 in the journal PLOS ONE, Anderson and her team used a remotely operated submarine to drop three pig carcasses into the Saanich Inlet, a body of salt water near Vancouver Island, British Columbia, at a depth of 330 feet (100 meters).

Nano ruffles in brain matter

Researchers have deciphered the role of nanostructures around brain cells in the central nervous system.

© Nils Blumenthal and Prasad Shastri
Scanning electron micrograph showing a neuron on a nanorough surface making intimate contact with the surface. Surfaces has been given a false color for visualization.
An accumulation of a protein called amyloid-beta into large insoluble deposits called plaques is known to cause Alzheimer's disease. One aspect of this illness that has not received much attention is which role the structure of the brain environment plays. How do macromolecules and macromolecular assemblies, such as polysaccharides, influence cell interaction in the brain?

In a paper published in the journal Proceedings of the National Academy of Sciences, Prof. Prasad Shastri and graduate student Nils Blumenthal, in collaboration with Prof. Bernd Heimrich and Prof. Ola Hermanson, have discovered that macromolecules or support cells like astrocytes provide well-defined physical cues in the form of random roughness or ruffles that have a crucial role in promoting and maintaining healthy interactions between cells in the hippocampus.

This brain area is regarded as the brain's GPS system: It processes and stores spatial information. In Alzheimer's disease, this area degenerates. Shastri says, "It has been long thought that only biological signals have a role in health and function of brain cells, but here we show that the structure of the molecules that surround these cells may be equally important."

Clean smell doesn't always mean clean air

Scientists are taking a closer look at aerosol formation involving an organic compound -- called limonene -- that provides the pleasant smell of cleaning products and air fresheners.

Some of the same chemical reactions that occur in the atmosphere as a result of smog and ozone are actually taking place in your house while you are cleaning. A researcher in Drexel's College of Engineering is taking a closer look at these reactions, which involve an organic compound -called limonene- that provides the pleasant smell of cleaning products and air fresheners. His research will help to determine what byproducts these sweet-smelling compounds are adding to the air while we are using them to remove germs and odors.

Secondary organic aerosols (SOAs) are microscopic particles created when ozone reacts with volatile organic gases such as limonene -the chemical name for the smell of oranges- or its cousin α-pinene, which is part of the smell of pine trees. Outdoors, this reaction happens all the time. It drives the formation of much of the atmospheric organic aerosol present in our environment. And in, population-dense urban areas -where enough suspended particles can be amassed- it contributes to the formation of the visible haze called smog.

Grandma was right! Arthritic joints can detect changes in weather

© Getty Images
Wrists are a common place people claim to feel pain related to weather changes.
When I was younger, my grandma would occasionally issue solemn prophesies for rain. These declarations would come after she'd spent a few minutes rubbing her arthritic wrists. With a pensive gaze, she'd credit the prediction to her aching joints.

I was reminded of this yesterday. I'd been working on my laptop when my ankle, titanium-braced from an old break, started throbbing. I thought nothing of it until I stepped outside, and into a surprise rainstorm. I'd always been skeptical of grandma's arthritic omens, but limping down the sidewalk in the wake of my own revelation gave me reason to reconsider. Could science have an answer for why some people seem to feel the weather in their bones?
Light Saber

Scientists engineer toxin-secreting stem cells to treat brain tumors

© Credit: Khalid Shah, MS, PhD, Harvard Stem Cell Institute
Encapsulated toxin-producing stem cells (blue) help kill brain tumor cells in the tumor resection cavity (green).
Harvard Stem Cell Institute scientists at Massachusetts General Hospital have devised a new way to use stem cells in the fight against brain cancer. A team led by neuroscientist Khalid Shah, MS, PhD, who recently demonstrated the value of stem cells loaded with cancer-killing herpes viruses, now has a way to genetically engineer stem cells so that they can produce and secrete tumor-killing toxins.

In the AlphaMed Press journal Stem Cells, Shah's team shows how the toxin-secreting stem cells can be used to eradicate cancer cells remaining in mouse brains after their main tumor has been removed. The stem cells are placed at the site encapsulated in a biodegradable gel. This method solves the delivery issue that probably led to the failure of recent clinical trials aimed at delivering purified cancer-killing toxins into patients' brains. Shah and his team are currently pursuing FDA approval to bring this and other stem cell approaches developed by them to clinical trials.

"Cancer-killing toxins have been used with great success in a variety of blood cancers, but they don't work as well in solid tumors because the cancers aren't as accessible and the toxins have a short half-life," said Shah, who directs the Molecular Neurotherapy and Imaging Lab at Massachusetts General Hospital and Harvard Medical School.
Arrow Down

Google wants to flood your body with tiny magnets to search for disease

Nano Particles
© The Verge
Google's ambition to cure death is beginning to take shape in a new product from its Google X division. Andrew Conrad, the head of the company's life sciences division, today announced the details of an effort that would use nanotechnology to identify signs of disease.

The project would employ tiny magnetic nanoparticles, said to be one-thousandth the width of a red blood cell, to bind themselves to various molecules and identify them as trouble spots.

Google's nanotechnology project, which would also involve a wearable magnetic device that tracks the particles, is said to be at least five years off, according to an accompanying report in the Wall Street Journal.

The company is still figuring out how many nanoparticles are necessary to identify markers of disease, and scientists will have to develop coatings for the particles that will let them bind to targeted cells. One idea is to deliver the nanoparticles via a pill that you would swallow.

DNA can carry current, a promising step toward molecular electronics

© Thinkstock
DNA could work as molecular circuit boards for extremely small, nano-sized electronics.
The promise of molecular electronics gets hoisted up the flagpole periodically, but now an international team of researchers based out of the Hebrew University of Jerusalem claim to have made a breakthrough with DNA molecules that they believe may be the most significant development in the last decade of molecular electronics research.

In research published in the journal Nature Nanotechnology, a international group of researchers hailing from Cyprus, Denmark, Italy, Spain and the United States has demonstrated that electric current can be transmitted through long DNA molecules. They believe that this demonstration could lead to the development of DNA-based electronic circuits.

Much research has focused on making DNA circuits. For instance, scientists have explored schemes in which DNA would serve as a kind of circuit board or scaffold for precisely assembling electronic components at resolutions as small as 6 nanometers. But so far it's all been without much success.

DNA was thought to be a promising basis for molecular circuits, because of its ability to self-assemble into various structures. But a big stumbling block has been that no one has been able to measure reliably or quantitatively the flow of current through the molecule.

Citizen science network produces accurate maps of atmospheric dust particles

iSPEX map

iSPEX map compiled from all iSPEX measurements performed in the Netherlands on July 8, 2013, between 14:00 and 21:00. Each blue dot represents one of the 6007 measurements that were submitted on that day. At each location on the map, the 50 nearest iSPEX measurements were averaged and converted to Aerosol Optical Thickness, a measure for the total amount of atmospheric particles. This map can be compared to the AOT data from the MODIS Aqua satellite, which flew over the Netherlands at 16:12 local time. The relatively high AOT values were caused by smoke clouds from forest fires in North America, which were blown over the Netherlands at an altitude of 2-4 km. In the course of the day, winds from the North brought clearer air to the northern provinces.
Measurements by thousands of citizen scientists in the Netherlands using their smartphones and the iSPEX add-on are delivering accurate data on dust particles in the atmosphere that add valuable information to professional measurements. The iSPEX team, led by Frans Snik of Leiden University, analyzed all measurements from three days in 2013 and combined them into unique maps of dust particles above the Netherlands. The results match and sometimes even exceed those of ground-based measurement networks and satellite instruments.

The iSPEX maps achieve a spatial resolution as small as 2 kilometers whereas satellite data are much courser. They also fill in blind spots of established ground-based atmospheric measurement networks. The scientific article that presents these first results of the iSPEX project is being published today in Geophysical Research Letters.

The iSPEX team developed a new atmospheric measurement method in the form of a low-cost add-on for smartphone cameras. The iSPEX app instructs participants to scan the blue sky while the phone's built-in camera takes pictures through the add-on. The photos record both the spectrum and the linear polarization of the sunlight that is scattered by suspended dust particles, and thus contain information about the properties of these particles. While such properties are difficult to measure, much better knowledge on atmospheric particles is needed to understand their effects on health, climate and air traffic.
Black Cat 2

Spontaneous gravity-related wave function collapse can suppress acoustic Schrodinger 'cat states'

Schrödinger's cat
© Credit: Wikipedia / CC BY-SA 3.0
Schrödinger's cat: a cat, a flask of poison, and a radioactive source are placed in a sealed box. If an internal monitor detects radioactivity (i.e. a single atom decaying), the flask is shattered, releasing the poison that kills the cat. The Copenhagen interpretation of quantum mechanics implies that after a while, the cat is simultaneously alive and dead. Yet, when one looks in the box, one sees the cat either alive or dead, not both alive and dead. This poses the question of when exactly quantum superposition ends and reality collapses into one possibility or the other.
Schrödinger's famous thought experiment in which a cat hidden in a box can be both dead and alive at the same time demonstrates the concept of superposition on the macroscopic scale. However, the existence of such "cat states" (or simply "Cats") would be problematic in reality, as cat states not only go against common sense, but also pose problems for understanding gravity and space-time.

"Different people emphasize different concerns about Cats," Lajos Diósi, a physicist the Wigner Research Center for Physics in Budapest, Hungary, told "Some people emphasize different ones at different times. So, allow me to pick up two arguments. Penrose (in my words): A Cat implies superposition of macroscopically different space-times, making physical time elusive. Myself: If we measure a Cat state a la von Neumann (why not?), then the collapse will macroscopically violate many conservation laws."

To address such problems, Diósi has expanded upon a model in which gravity-related spontaneous wave function collapses can suppress Schrödinger cat states, forcing them to take on only one value. Diósi's paper on suppressing cat states is published in a recent issue of the New Journal of Physics.