Science & TechnologyS


Laptop

DNA can carry current, a promising step toward molecular electronics

Dexter Johnson
IEEE Spectrum
Mon, 27 Oct 2014 20:00 UTC
DNA
© ThinkstockDNA 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.
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Map

Citizen science network produces accurate maps of atmospheric dust particles


Phys.org
Tue, 28 Oct 2014 17:35 UTC
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.
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Black Cat 2

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

Lisa Zyga
Phys.org
Tue, 28 Oct 2014 17:00 UTC
Schrödinger's cat
© Credit: Wikipedia / CC BY-SA 3.0Schrödinger'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 Phys.org. "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.
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Bug

Watch your email attachments: Microsoft office bug lets hackers take over computers


RT
Mon, 27 Oct 2014 00:00 UTC
Microsoft
© AFP Photo/Sam Yeh
A dangerous new security vulnerability has been discovered in Microsoft's Office software, threatening to hijack users of virtually every existing version of Windows.

The bug in question affects programs like Word, PowerPoint, and Excel - and could allow an intruder to gain access to and control over a user's entire computer.

Already, Microsoft has discovered that hackers are using the bug to hack computers through PowerPoint. Windows users should be wary of opening PowerPoint files sent via email unless they completely trust the original source, the company wrote in an online security advisory. Even in cases involving trusted sources, it has advised to not open the files received unexpectedly.
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Robot

Real life Transformer introduced at Tokyo expo

Greta McClain
Digital Journal
Mon, 27 Oct 2014 04:59 UTC
The J-deite Quarter
© Screen Capture
If you are a Transformer fan who dreams of someday owning your own transforming robot, Project J-deite will soon make your dream a reality.

The project, which is a collaborative effort between Japan's Brave Robotics, Asratec and Takara Tommy, is the brain child of Kenji Ishida, founder of Brave Robotics.

Ishida's passion for robotics began at the age of 14 and by the time he was 21, he had built his first bi-pedal walking robot. Now, he and his team have developed the J-deite Quarter, a humanoid bi-pedal robot made out of 3D-printed parts.

Introduced last week at the Digital Content Expo in Tokyo, attendees and the media got a glimpse of what J-deite Quarter can do.

The transforming robot stands 1.3 meters (4.3 feet) tall and can walk at a rate of 1 kilometer per hour (0.62 mph). Geek.com reports it takes J-deite Quarter approximately 30 seconds to transform from a walking robot to car mode. Once in car mode, it can travel up to ten kilometers per hour (6.2 mph).
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Satellite

Space station dodging 'space junk' - yet again!

Marcia Dunn
phys.org
Mon, 27 Oct 2014 19:16 UTC
The International Space Station has to sidestep a piece of junk on the same day that a Virginia company is sending fresh supplies.

NASA says debris from an old, wrecked Russian satellite was due to come dangerously close to the orbiting lab Monday afternoon - a gap of just two-tenths of a mile. To keep the station and its six inhabitants safe, the station was going to maneuver well out of harm's way.

Mission Control says the move won't affect Monday evening's planned launch of a commercial supply ship.

Orbital Sciences Corp.'s unmanned Cygnus capsule holds 5,000 pounds of cargo, including mini research satellites. Liftoff is scheduled for 6:45 p.m. (2245 GMT) from Wallops Island, Virginia.

The launch, coming a half-hour after sunset, should be visible along much of the Eastern Seaboard.

Comment: If this really is "debris from an old, wrecked Russian satellite", perhaps we ought to ask the following question. Why have more satellites been crashing to Earth since 2011?

Could it be because they're being knocked out of orbit by incoming meteors and comet fragments?

See: Satellite debris or UFO Unidentified metal sphere falls from the sky in Brazil

and Space station dodges space junk again

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Magnify

How the air we breathe was created by Earth's tectonic plates

Simon Redfern
Phys.org
Mon, 27 Oct 2014 12:17 UTC
Volcanism
© Simon RedfernVolcanism, driven by plate tectonics, built Earth’s atmosphere to make a habitable planet.
How is it that Earth developed an atmosphere that made the development of life possible? A study published in the journal Nature Geoscience links the origins of Earth's nitrogen-rich atmosphere to the same tectonic forces that drive mountain-building and volcanism on our planet. It goes some way to explaining why, compared to our nearest neighbours, Venus and Mars, Earth's air is richer in nitrogen.

The chemistry of the air we breathe is, at least partly, the result of billions of years of photosynthesis. Plant life has transformed our world from one cloaked in a carbon dioxide-rich atmosphere - as seen on Mars or Venus - to one with significant oxygen. About a fifth of the air is made up of oxygen, and almost all the rest is nitrogen. But the origins of the relatively high nitrogen content of Earth's air have been something of a mystery.

Geoscientists Sami Mikhail and Dimitri Sverjensky of the Carnegie Institution of Washington have calculated what nitrogen is expected to do when it is cycled through the rocks of the deep Earth by the churning cycle of plate tectonics. Active volcanoes not only shower volcanic rock and superheated ash as they erupt molten rock into the air, they also vent huge amounts of gas from Earth's depths. The latest eruptions in Iceland, for example, have been noted for the amounts of sulphurous fumes that they have emitted.

Alongside sulphur, steam and carbon dioxide, volcanoes next to active tectonic plate boundaries pump massive quantities of nitrogen into the air. Mikhail and Sverjensky explain this through the chemistry of what goes on beneath those volcanic roots.
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Telescope

Astronomers capture first ever data of an exploding fireball from a nova star

Melissa Davey
The Guardian, UK
Mon, 27 Oct 2014 06:16 UTC
Researchers reveal the nova was about 14,800 light years from the sun, meaning the explosion witnessed in August last year happened 15,000 years ago

nova
© David A HardyAn artist’s impression of a star system responsible for a nova.
A team of astronomers have captured the first images of a thermonuclear fireball from a nova star, allowing them to track the explosion as it expanded.

The nova was detected last year in the constellation Delphinus by the Chara Array infrared telescope in the US.

Researchers from 17 institutions around the world, including the University of Sydney and the Australian National University, analysed the resulting data.

It revealed with "unprecedented clarity" how the fireball evolves as the gas fuelling it expands and cools, Professor Peter Tuthill, a co-author on the study, said.

"We haven't had the ability to witness such exquisite magnification or high resolution of images until very recently, when we started building these powerful Array telescopes," Tuthill, from the University of Sydney's Institute for Astronomy, said.
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Magnify

How cells know which way to go

Shawna Williams
EurekAlert!
Mon, 27 Oct 2014 11:00 UTC
Two new studies shed light on how cells sense and respond to chemical trails

Image
© Yulia Artemenko/Johns Hopkins MedicineA lab-grown human leukemia cells move toward a pipette tip holding an attractive chemical.
Amoebas aren't the only cells that crawl: Movement is crucial to development, wound healing and immune response in animals, not to mention cancer metastasis. In two new studies from Johns Hopkins, researchers answer long-standing questions about how complex cells sense the chemical trails that show them where to go - and the role of cells' internal "skeleton" in responding to those cues.

In following these chemical trails, cells steer based on minute differences in concentrations of chemicals between one end of the cell and the other. "Cells can detect differences in concentration as low as 2 percent," says Peter Devreotes, Ph.D., director of the Department of Cell Biology at the Johns Hopkins University School of Medicine. "They're also versatile, detecting small differences whether the background concentration is very high, very low or somewhere in between."

Working with Pablo Iglesias, Ph.D., a professor of electrical and computer engineering at Johns Hopkins, Devreotes' research group members Chuan-Hsiang Huang, Ph.D., a research associate, and postdoctoral fellow Ming Tang, Ph.D., devised a system for watching the response of a cellular control center that directs movement. They then subjected amoebas and human white blood cells to various gradients and analyzed what happened. "Detecting gradients turns out to be a two-step process," says Huang. "First, the cell tunes out the background noise, and the side of the cell that is getting less of the chemical signal just stops responding to it. Then, the control center inside the cell ramps up its response to the message it's getting from the other side of the cell and starts the cell moving toward that signal." The results appear on the Nature Communications website on Oct. 27.
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Magnify

New pathway found: Mutant cells fail to deliver new proteins to correct location


phys.org
Sun, 26 Oct 2014 09:56 UTC
DNA
Proteins are the machinery that accomplishes almost every task in every cell in every living organism. The instructions for how to build each protein are written into a cell's DNA. But once the proteins are constructed, they must be shipped off to the proper place to perform their jobs. New work from a team of scientists led by Carnegie's Munevver Aksoy and Arthur Grossman, describes a potentially new pathway for targeting newly manufactured proteins to the correct location. Their work is published in The Plant Cell journal.

The team's discovery concerns a cellular organelle that has been called an acidocalcisome. It is a compartment that isolates potential harmful or disruptive compounds from the rest of the cell and is also involved in the turnover of cellular components (similar to the so-called lysosome in animals). They are rich in phosphate-containing molecules and the team noted that they build up to high levels when cells of the single-celled, green alga Chlamydomonas are deprived of sulfur. They discovered that acidocalcisomes are also, surprisingly, involved in targeting proteins out into the cell space between the cell's membrane and the cell wall.

Working with Chlamydomonas, the team, which also included Carnegie's Wirulda Pootakham, was examining the organism's responses to nutrient deficiency. They found that mutant cells lacking the ability to form these acidocalcisomes also lacked the ability to cope with sulfur and nitrogen deprivation adequately.

What appears to happen with these mutants is that the proteins that specialize in helping the cell survive a deficiency of sulfur or nitrogen don't get shipped out to the space between the membrane and cell wall where they are needed. Because of this, feedback is sent to stop construction of the proteins (and the messenger RNA that encodes those proteins) and the entire response to nutrient deficiency is derailed.
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