NASA Chandra Finds Fastest Wind From Stellar-Mass Black Hole

This artist's impression shows a binary system containing a stellar-mass black hole called IGR J17091-3624, or IGR J17091 for short.

The strong gravity of the black hole, on the left, is pulling gas away from a companion star on the right.

This gas forms a disk of hot gas around the black hole, and the wind is driven off this disk.

New observations with NASA's Chandra X-ray Observatory clocked the fastest wind ever seen blowing off a disk around this stellar-mass black hole.

Stellar-mass black holes are born when extremely massive stars collapse and typically weigh between five and 10 times the mass of the Sun.

The record-breaking wind is moving about twenty million miles per hour, or about three percent the speed of light.

This is nearly ten times faster than had ever been seen from a stellar-mass black hole, and matches some of the fastest winds generated by supermassive black holes, objects millions or billions of times more massive.

Another unanticipated finding is that the wind, which comes from a disk of gas surrounding the black hole, may be carrying away much more material than the black hole is capturing.

The high speed for the wind was estimated from a spectrum made by Chandra in 2011. A spectrum shows how intense the X-rays are at different energies.

Ions emit and absorb distinct features in spectra, which allow scientists to monitor them and their behavior.

A Chandra spectrum of iron ions made two months earlier showed no evidence of the high-speed wind, meaning the wind likely turns on and off over time.

Image Credit: NASA/CXC/M.Weiss

OxFord University: Flesh-eating bacteria inspire superglue

A bio-inspired superglue has been developed by Oxford University researchers that can’t be matched for sticking molecules together and not letting go.

It could prove to be a very useful addition to any toolbox for biotechnology or nanotechnology. You could use the glue to grab hold of proteins or stick them immovably to surfaces. You could even use it to assemble proteins and enzymes to build new structures on the nanometre scale.

‘We’re very interested in creating protein assemblies. We want to be able to treat proteins like Lego,’ explains Dr Mark Howarth, who with his graduate student Bijan Zakeri at the Department of Biochemistry developed the superglue. ‘But previously we’ve been limited to ill-controlled processes or have had to build using weak biological interactions.’

The Oxford biochemists came up with their new super-strength molecular glue by engineering an unusual protein from a type of bacteria that can cause life-threatening disease.

While many people carry Streptococcus pyogenes in their throat without any problems, the bacteria can cause infections. Some are mild, like impetigo in infants or a sore throat, but some can kill, like toxic shock syndrome or flesh-eating disease.

What attracted the biochemists’ interest was a specific protein which the bacteria use to bind and invade human cells.

‘The protein is special because it naturally reacts with itself and forms a lock,’ says Mark.

All proteins consist of amino acids linked together into long chains by strong covalent bonds. The long chains are folded and looped up into three-dimensional structures held together by weaker links and associations.

The protein FbaB from S. pyogenes has a 3D structure that is stabilised by another covalent bond. This strong chemical bond forms in an instant and binds the loops of the amino acid chain together with exceptional strength.

Mark and his colleagues reckoned with a bit of engineering they could split the protein around this extra covalent bond. Then, when the two parts were brought together again, they might dock and form this strong bond once more.

The two parts would be locked together immovably – stapling together anything else attached to their tails.That is what the researchers have now demonstrated in this week’s PNAS.

They’ve nicknamed the larger fragment which formed the bulk of the original protein ‘SpyCatcher’. Once SpyCatcher gets hold of the shorter protein segment, ‘SpyTag’, it never lets go.

At least, the researchers with their collaborators at the University of Miami tried to measure the force needed to pull apart SpyTag from SpyCatcher using an atomic force microscope.

But when they pulled on each end, the chemical links holding the proteins to the apparatus broke first. Boiling in detergent won’t separate the protein fragments either.

‘Our system forms rapid covalent bonds with high efficiency and high stability,’ says Mark.

When SpyCatcher and SpyTag are brought together, they bond in minutes with high yield. It doesn’t matter whether it is in acidic or neutral conditions, or whether it is 4°C or 37°C.

They will stick together in test tube reactions or inside cells. And importantly, they don’t stick to other things – there’s no equivalent of getting your fingers stuck to the Airfix model you’re building.

Mark explains that there isn’t really any equivalent way to bind biomolecules together. There are chemical reactions that can join two proteins together covalently but often only small proportions react, they take a long time, or they require UV light, toxic catalysts or reaction conditions that could damage living cells.

The ability to attach SpyCatcher and SpyTag onto other molecules you want to glue together could have many applications. For example, sticking all the enzymes involved in a chemical process into a small factory could speed reactions and increase yields.

Or you might want to bring all the elements together that plants use to turn sunlight into energy with only water as a waste product. Scientists have long wanted to come up with ways of achieving photosynthesis artificially for useable green energy.

But the first uses of the molecular superglue may well be in the research lab, grabbing hold of structures within biological cells. That way you could resist the forces generated by important motors, machines and transporters inside the cell.

Mark and his team are now working on developing the molecular superglue technology through Isis Innovation, the University of Oxford’s technology transfer company.

Major Breathrough in TB Research: Questions answered!

After three decades of searching, the random screening of a group of compounds against the bacterium that causes pulmonary tuberculosis has led scientists to a eureka discovery that breaks through the fortress that protects the bacterium and allows it to survive and persist against treatments.

The two findings, which occurred at Colorado State University, are published today in Nature Chemical Biology.

The article describes the discovery of an important cell function in the mycobacterium that causes tuberculosis which allows the mycobacterium to survive. The researchers also discovered a compound that prevents this cell function.

The bacterium that causes tuberculosis is extremely difficult to kill and current tuberculosis drugs on the market don’t do well to treat it. Six months of multiple antibiotics are generally required to treat tuberculosis in most people, and many current drugs no longer work because of resistant strains of the bacterium that causes tuberculosis. Scientists hope that finding new drugs to kill the bacteria in ways different than current drugs will help tackle those strains.

Cell envelopes form a virtually impenetrable bubble around the bacterium cell and protect it. Mycolic acids are key portions of this bacterium’s cell envelope. They are made inside the cell, but have to cross the cell membrane, with the help of a transporter, to reach their final location in the cell envelope.

“Without mycolic acids in the cell envelope, the bacteria die,” said Mary Jackson, one of the leading researchers on the project. Jackson is a professor in the Department of Microbiology, Immunology and Pathology.

“While randomly testing a group of compounds against the bacterium in the lab, we found one class of compounds that powerfully stops the growth of the bacterium, a significant finding on its own.

When we looked closer, we found that the compounds stopped a transporter from moving mycolic acids from inside to outside the cell, which also means this discovery identified a new method of killing the bacterium.

Scientists have been trying to find the transporter of mycolic acids for decades, knowing that understanding how to stop mycolic acids from reaching the surface of the cell could lead to new tuberculosis treatments.

“If mycolic acids cannot be transported, the tuberculosis bacterium cannot grow,” said Mike McNeil, co-researcher on the project with Jackson and also a professor in the Department of Microbiology, Immunology and Pathology at CSU.

“It is like a factory making bricks and no way to get them to the construction site. It is a long, hard road to develop new, badly-needed tuberculosis drugs. Still, we are optimistic that this research will strongly contribute to the worldwide crusade to diminish suffering and death caused by tuberculosis.”

Jackson, McNeil and partner researchers from CSU and St. Jude Children’s Hospital in Memphis also note that there are other potential transporters in the bacterium that resemble the one just found.

“We hope that our work also will pave the way to understanding what those transporters do in the cell and finding how to target them to kill the mycobacteria,” Jackson said.

Tuberculosis causes the death of more than 1.5 million people around the globe each year.

ESA Swarm constellation heads north

The Swarm mission will study the complexities of Earth's protective magnetic field. The magnetic field acts as a shield, protecting the planet from charged particles that stream towards Earth in solar winds. Without this shield, life on Earth would be impossible. 

The field is mainly generated deep inside Earth by an ocean of swirling iron that makes up the liquid outer core. How the magnetic field is generated and how it changes over time is complex and not fully understood. But with a new generation of magnetometers, Swarm will provide greater insight into these natural processes and the 'weather' in space. Credits: ESA/AOES Medialab.

The three satellites that make up ESA's Swarm magnetic field mission were unvieled last week to the media. Following a demanding testing programme, the satellites were displayed in the cleanroom before they are shipped to Russia for their July launch.

Swarm is ESA's first constellation of Earth observation satellites designed to measure the magnetic signals from Earth's core, mantle, crust, oceans, ionosphere and magnetosphere, providing data that will allow scientists to study the complexities of our protective magnetic field.

The magnetic shield protects the planet from charged particles that stream in as the solar wind. Without this shield, life on Earth would be impossible.

This shield is generated mainly deep inside Earth by an ocean of swirling iron in the liquid outer core. How the magnetic field is created and how it changes over time is complex and not fully understood.

This force is constantly changing - at the moment, it shows signs of significant weakening.

But with a new generation of sensors, the Swarm constellation will provide greater insight into these natural processes and the 'weather' in space.

Swarm will be ESA's fourth Earth Explorer mission in orbit, following GOCE, SMOS and CryoSat.

In five months, the trio of satellites will be launched together on a Rockot launcher from the Plesetsk Cosmodrome in northern Russia.

Two will orbit very close together at the same altitude - initially at about 460 km - while the third satellite will be in a higher orbit of 530 km.

The different near-polar orbits, along with the various Swarm instruments, improve the sampling in space and time. This helps to distinguish between the effects of different sources of magnetism.

X-rays illuminate the interior of the Moon

This is an image of an artificial moon rock sample, measuring about half a millimeter across, made with an electron microprobe at ambient temperature after the experiment with X-rays. 

The fragmentation of the sample occurred when it was extracted from the small diamond cylinder in which it had been melted under high pressure and temperature. Credit: Nature.

Contrary to Earth, our Moon has no active volcanoes, and the traces of its past volcanic activity date from billions of years ago.

This is surprising, because recent Moonquake data suggest that there is plenty of liquid magma deep within the Moon because part of the rocks residing there are thought to be molten.

Scientists have now identified a likely reason for this peaceful surface life: the hot, molten rock in the Moon's deep interior could be so dense that it is simply too heavy to rise to the surface like a bubble in water.

For their experiments, the scientists produced microscopic copies of moon rock collected by the Apollo missions and melted them at the extremely high pressures and temperatures found inside the Moon.

They then measured their densities with powerful X-rays. The results are published in the Journal Nature Geosciences on 19 February 2012.

The team was led by Mirjam van Kan Parker and Wim van Westrenen from VU University Amsterdam and comprised scientists from the Universities of Paris 6/CNRS, Lyon 1/CNRS, Edinburgh, and the European Synchrotron Radiation Facility (ESRF) in Grenoble.

Five decades after the Apollo missions, the formation and geological history of the Moon still hold many secrets. The astronauts not only returned 380 kg of Moon rocks to Earth but also placed many scientific instruments on the lunar surface.

Last year, NASA scientists published a new model for the make-up of the interior of the Moon, using Moonquake data from these Apollo-era seismometers. Renee Weber and her colleagues claim that the deepest parts of the lunar mantle, bordering on the small metallic core, are partially molten, by up to 30 per cent.

In the Earth, such bodies of magma tend to move towards the surface leading to volcanic eruptions. If the deep interior of the Moon contains so much magma, why don't we see spectacular volcanic eruptions at its surface?

Read more of this article here

HiRise Images: Mars rocks indicate relatively recent quakes, volcanism

Images of a martian landscape offer evidence that the Red Planet’s surface not only can shake like the surface of Earth, but has done so relatively recently.

If Marsquakes do indeed take place, said the scientists who analyzed the high-resolution images, our nearest planetary neighbor may still have active volcanism, which could help create conditions for liquid water.

With High Resolution Imaging Science Experiment (HiRISE) imagery, the research team  examined boulders along a fault system known as Cerberus Fossae, which cuts across a very young (few million years old) lava surface on Mars.

By analyzing boulders that toppled from a martian cliff, some of which left trails in the coarse-grained soils, and comparing the patterns of dislodged rocks to such patterns caused by quakes on Earth, the scientists determined the rocks fell because of seismic activity.

The martian patterns were not consistent with how boulders would scatter if they were deposited as ice melted, another means by which rocks are dispersed on Mars.

Gerald Roberts, an earthquake geologist with Birkbeck, an institution of the University of London, who led the study, said that the images of Mars included boulders that ranged from two to 20 meters (6.5 to 65 feet) in diameter, which had fallen in avalanches from cliffs.

The size and number of boulders decreased over a radius of 100 kilometers (62 miles) centered at a point along the Cerberus Fossae faults.


“This is consistent with the hypothesis that boulders had been mobilized by ground-shaking, and that the severity of the ground-shaking decreased away from the epicenters of marsquakes,” Roberts said.

The study, by Roberts and his colleagues, will be published Thursday in the Journal of Geophysical Research-Planets, a publication of the American Geophysical Union (AGU).

Seeing Things That Aren’t There? Charles Bonnet Syndrome

One woman saw a fully dressed Royal Canadian mountie in her living room. Another saw the same red brick building in every part of town, as well as in the country. One man saw monkeys with red hats and blue coats playing in his yard.

They were all experiencing Charles Bonnet (“bo-nay”) Syndrome.

“Do you ever see something you know is not there, but it looks real?” It’s a question that Lylas G. Mogk, M.D., and Raman Deol, O.D., of the Henry Ford Center for Vision Rehabilitation and Research in metropolitan Detroit, always ask their low-vision patients.

Low vision that cannot be improved through corrective lenses or surgery can be the result of macular degeneration, glaucoma, diabetes, stroke, or other causes.

Some of their patients respond that they see purple flowers everywhere, even in winter. Others see animals, people, buildings, or geometric, quilt-like patterns. They rarely share their experience with their families, for fear of being misunderstood. Some wonder whether the visions suggest early dementia.

In 1789, Swiss naturalist Charles Bonnet described the visions of his father-in-law, who had low vision and saw people, animals and other objects that he knew were not real.

Bonnet himself experienced phantom visions later in his life, similar to those of his father-in-law. Bonnet’s discovery went largely unnoticed for 150 years until the 1930s, when doctors rediscovered his files and named the syndrome after him.

The frequently undiagnosed Charles Bonnet Syndrome is very common, affecting 20 – 30 percent of those with low vision. Some may experience it for a few months, others for several years.

The images can occur daily or only occasionally, with the same image appearing to the same person. There is no cure, but most people are not bothered by the images, and many find them interesting or amusing, especially once they understand it’s just their eyes playing tricks on them.

Although the cause is not known, the images can be compared to the “phantom pain” that can be felt by people who have had a limb amputated.

The nerves that were connected to the missing limb still send signals to the brain. In our visual system, the nerves no longer receiving visual messages can cause the brain to “see” realistic images, while recognizing they are not real.

Many physicians are not yet aware of Charles Bonnet Syndrome, and may mistake it for psychotic hallucinations. Patients with the syndrome have been misdiagnosed and prescribed anti-psychotic medications.

To identify Charles Bonnet Syndrome, ophthalmologists use these criteria:
• The person has low vision.
• The images occur when the person is conscious, with open eyes.
• The person recognizes the images are not real.
• The same image appears repeatedly, superimposed on the real world. For example, the person sees a room normally, but the wall appears to have flowers on it and only that same image of flowers recurs to that same person.
• Images are only visual; they may move, but there are no sounds or smells. It’s like seeing a picture, or watching a silent movie.
• Images are common, familiar objects. They may be amusing or mildly annoying, but not frightening.
People with low vision who believe they may be experiencing Charles Bonnet Syndrome should discuss it with their ophthalmologist.