Diamonds are a laser’s best friend

Tomorrow’s lasers may come with a bit of bling, thanks to a new technology that uses man-made diamonds to enhance the power and capabilities of lasers. Researchers in Australia have now demonstrated the first laser built with diamonds that has comparable efficiency to lasers built with other materials.

This “Raman” laser has applications that range from defense technologies and trace gas detectors to medical devices and satellite mapping of greenhouse gases. The special properties of diamonds offer a stepping stone to more powerful lasers that can be optimized to produce laser light colors currently unavailable to existing technologies.

Richard Mildren of Macqaurie University in Sydney, New South Wales, Australia and Alexander Sabella of the Defence Science and Technology Organisation in Edinburgh, South Australia developed the device, described in the current issue of the Optical Society (OSA) journal Optics Letters.

“Diamond is quite a bizarre material with unique and extreme properties,” says Mildren. “Single crystal diamond is very new on the scene as an optical and laser material.”

Existing Raman lasers typically use crystals of silicon, barium nitrate or metal tungstate to amplify light created by a pump laser. Compared to these materials, diamond has a higher optical gain (ability to amplify) as well as a greater thermal conductivity (ability to conduct heat), making it ideal for high-power applications. Diamond crystals also can be made to generate a wider variety of wavelengths of light, each of which have its own applications—from ultraviolet light at 225 nanometers to far-infrared light at 100 microns.

In 2008, Mildren built the first diamond Raman laser, reported in Optics Express, OSA’s open-access journal. This proof-of-principle device was only 20 percent as efficient as the best barium nitrate lasers.

In the past year, the industrial process used to grow these artificial diamonds—chemical vapor deposition—has greatly improved, allowing the synthesis of crystals with a lower birefringence (less likely to split apart an incoming beam of light).

“The material is now good enough to start moving into applications that are of real practical interest,” says Mildren.

Now Mildren’s current laser, which uses a 6.7 mm long diamond, achieves an efficiency of 63.5 percent, which is competitive with the 65 percent efficiency achieved by existing Raman lasers. The device is currently optimized to produce yellow laser light useful for medical applications such as eye surgery, and other applications should be possible with different optimization schemes.

via Diamonds are a laser’s best friend.

The Potential Adverse Health and Environmental Effects of Nanoparticles

A new study raises the possibility that flies and other insects that encounter nanomaterial “hot spots,” or spills, near manufacturing facilities in the future could pick up and transport nanoparticles on their bodies, transferring the particles to other flies or habitats in the environment. The study on carbon nanoparticles – barely 1/5,000th the width of a human hair -is scheduled for the Aug. 15 issue of ACS’ Environmental Science + Technology.

Researchers are reporting that carbon nanoparticles can be transmitted by fruit flies and that certain nanoparticles can be toxic to adult flies.

Scientists use fruit flies as stand-ins for humans and other animals in certain kinds of research. There were no apparent ill effects on fruit fly larvae that ate food containing high concentrations of nanoparticles. However, adult flies died or were incapacitated when their bodies were exposed to large amounts of certain nanoparticles.

During the experiments, the researchers noted that contaminated flies transferred nanoparticles to other flies, and realized that such transfer could also occur between flies and humans in the future.

via The Potential Adverse Health and Environmental Effects of Nanoparticles.

I saw this and wondered if nanoparticles might be responsible for killing the honey bees. Has anyone looked into this possibility?

Using magnetism to turn drugs on and off

Many medical conditions, such as chronic pain, cancer and diabetes, require medications that cannot be taken orally, but must be dosed intermittently, on an as-needed basis, over a long period of time. A few delivery techniques have been developed, using an implanted heat source, an implanted electronic chip or other stimuli as an “on-off” switch to release the drugs into the body. But thus far, none of these methods can reliably do all that’s needed: repeatedly turn dosing on and off, deliver consistent doses and adjust doses according to the patient’s need.

Researchers led by Daniel Kohane, MD, PhD of Children’s Hospital Boston, funded by the National Institutes of Health, have devised a solution that combines magnetism with nanotechnology.

The team created a small implantable device, less than ½” in diameter, that encapsulates the drug in a specially engineered membrane, embedded with nanoparticles (approximately 1/100,000 the width of a human hair) composed of magnetite, a mineral with natural magnetic properties. When a magnetic field is switched on outside the body, near the device, the nanoparticles heat up, causing the gels in the membrane to warm and temporarily collapse. This opens up pores that allow the drug to pass through and into the body. When the magnetic force is turned off, the membranes cool and the gels re-expand, closing the pores back up and halting drug delivery. No implanted electronics are required.

The device, which Kohane’s team is continuing to develop for clinical use, is described in the journal Nano Letters (published online September 8, DOI: 10.1021/nl9018935).

“A device of this kind would allow patients or their physicians to determine exactly when drugs are delivered, and in what quantities,” says Kohane, who directs the Laboratory for Biomaterials and Drug Delivery in the Department of Anesthesiology at Children’s.

In animal experiments, the membranes remained functional over multiple cycles. The size of the dose was controllable by the duration of the “on” pulse, and the rate of release remained steady, even 45 days after implantation.

via Using magnetism to turn drugs on and off.

Invading black holes explain cosmic flashes

Black holes are invading stars, providing a radical explanation to bright flashes in the universe that are one of the biggest mysteries in astronomy today.

The flashes, known as gamma ray bursts, are beams of high energy radiation – similar to the radiation emitted by explosions of nuclear weapons – produced by jets of plasma from massive dying stars.

The orthodox model for this cosmic jet engine involves plasma being heated by neutrinos in a disk of matter that forms around a black hole, which is created when a star collapses.

But mathematicians at the University of Leeds have come up with a different explanation: the jets come directly from black holes, which can dive into nearby massive stars and devour them.

Their theory is based on recent observations by the Swift satellite which indicates that the central jet engine operates for up to 10,000 seconds – much longer than the neutrino model can explain.

Mathematicians believe that this is evidence for an electromagnetic origin of the jets, i.e. that the jets come directly from a rotating black hole, and that it is the magnetic stresses caused by the rotation that focus and accelerate the jet’s flow.

For the mechanism to operate the collapsing star has to be rotating extremely rapidly. This increases the duration of the star’s collapse as the gravity is opposed by strong centrifugal forces.

One particularly peculiar way of creating the right conditions involves not a collapsing star but a star invaded by its black hole companion in a binary system. The black hole acts like a parasite, diving into the normal star, spinning it with gravitational forces on its way to the star’s centre, and finally eating it from the inside.

“The neutrino model cannot explain very long gamma ray bursts and the Swift observations, as the rate at which the black hole swallows the star becomes rather low quite quickly, rendering the neutrino mechanism inefficient, but the magnetic mechanism can,” says Professor Komissarov from the School of Mathematics at the University of Leeds.

“Our knowledge of the amount of the matter that collects around the black hole and the rotation speed of the star allow us to calculate how long these long flashes will be – and the results correlate very well with observations from satellites,” he adds.

via Invading black holes explain cosmic flashes.

Portable and precise gas sensor could monitor pollution and detect disease

In the air, it is a serious pollutant. In the body, it plays a role in heart rate, blood flow, nerve signals and immune function.

Nitric oxide, a gas well known to scientists for its myriad functions, has proven challenging to measure accurately outside the laboratory. A team of Princeton and Rice University researchers has demonstrated a new method of identifying the gas using lasers and sensors that are inexpensive, compact and highly sensitive. Such a portable device, suitable for large-scale deployment, could be of great value to atmospheric science, pollution control, biology and medicine.

Nitric oxide is so potent that a few molecules of it per billion, or even trillion, molecules of air promote smog, acid rain and depletion of the ozone layer. Similarly tiny amounts in a patient’s breath could help diagnose asthma and other disorders.

The researchers believe their device could find uses ranging from the study and control of car and truck emissions to monitoring human exposure to pollutants in urban and industrial environments. For medical uses the device is particularly attractive because the results are not corrupted by water vapor, which is present in breath samples. Testing for nitric oxide in a patient’s breath, for example, could reveal chronic obstructive pulmonary disease and inflammation.

“The sensor we’ve developed is much more accurate and sensitive than existing systems, yet is far more compact and portable,” said Gerard Wysocki, assistant professor of electrical engineering at Princeton.

Wysocki is a co-leader of a team that developed the system and conducted preliminary tests during the 2008 Olympic Games in Beijing. The team included Rice researchers Frank Tittel and 1996 Nobel laureate Robert Curl, both pioneers in the field of molecular detection using lasers, as well as Rafał Lewicki and James Doty III, also of Rice. The team published its results in the Aug. 4 issue of the Proceedings of the National Academy of Sciences.

With improvements made after the Beijing test, the system could be made into a portable, shoe-box-sized device ideally suited for mass deployment in large-scale unattended sensor networks for global, real-time, continuous monitoring of nitric oxide and other gases present in trace amounts.

Existing systems to detect nitric oxide and other trace gases have a variety of drawbacks. Some, such as carbon monoxide sensors for homes, are compact and inexpensive, but not very sensitive. These sensors can at best detect gases at parts-per-million concentrations — they can’t handle the parts-per-billion level, let alone the parts-per-trillion level that some applications require. High-end systems, such as mass spectrometers and gas chromatographs, are much more sensitive, but are slow, bulky, complicated and expensive — and impractical for use outside of a lab.

…

The new system, in contrast, uses a quantum cascade laser, a state-of-the-art device ideally suited for this sensing technique. This makes it possible to reliably detect the gas at a concentration of a few parts-per-billion. The device is so precise it can distinguish between different isotopes of nitrogen and oxygen in the nitric oxide molecules.

“It’s remarkable we have that kind of sensitivity,” said Curl, who laid the groundwork for the detection technique in a paper he co-wrote with Tittel nearly 30 years ago.

“A portable sensor that can continuously measure nitric oxide with such high sensitivity is a real breakthrough,” said Tittel.

Unlike other systems that need several liters of the sample gas, the new sensor needs only a few milliliters of it, inside a container just about 16 inches long and a half inch in diameter. This frugality is particularly important in delicate biological applications such as cell-culture studies, said Wysocki. Also important, the new system can run much longer without intervention — several hours compared to just a few minutes for even the best existing ones — which will allow for long-term unattended operation.

Princeton researchers are working on various enhancements to the technology, further shrinking the size of the device and exploring an even more sensitive method of analysis called coherent detection. “This technique could help us achieve parts-per-trillion sensitivity,” Wysocki said.

via Portable and precise gas sensor could monitor pollution and detect disease.

French ‘pass’ piracy legislation

The French National Assembly has passed a draft law that would allow illegal downloaders to be thrown off the net.

The law was narrowly passed by 285 votes to 225.

The French hard-line policy on piracy has drawn worldwide attention as nations around the globe grapple with the issue of piracy.

The ruling majority UMP voted in favour but the Socialist Party has already announced that they will appeal to the Constitutional Court once again.

An earlier version of the bill was ruled unconstitutional and a compromise version was hammered out.

The Constitutional Court insisted that a judge rather than a high authority had to rule on the issue of whether to disconnect users.

The document will only be adopted definitely if a commission – made up of seven senators and seven deputies – can agree a joint version in the next few days.

The legislation is backed by President Nicolas Sarkozy.

The proposed legislation operates under a “three strikes” system. A new state agency would first send illegal file-sharers a warning e-mail, then a letter and finally cut off their connection if they were caught a third time.

While it is backed by the film and record industries, consumer groups have warned that innocent people may get punished.

The European Parliament is currently considering whether cutting off internet access is a breach of human rights.

via BBC NEWS | Technology | French ‘pass’ piracy legislation.

What do you think, is Internet access a human right? I think it should be simply because it is becoming our primary vehicle of education and self expression.

Birth control could help combat climate change

Giving contraceptives to people in developing countries could help fight climate change by slowing population growth, experts said Friday.

More than 200 million women worldwide want contraceptives, but don’t have access to them, according to an editorial published in the British medical journal, Lancet. That results in 76 million unintended pregnancies every year.

If those women had access to free condoms or other birth control methods, that could slow rates of population growth, possibly easing the pressure on the environment, the editors say.

“There is now an emerging debate and interest about the links between population dynamics, sexual and reproductive health and rights, and climate change,” the commentary says.

In countries with access to condoms and other contraceptives, average family sizes tend to fall significantly within a generation. Until recently, many U.S.-funded health programs did not pay for or encourage condom use in poor countries, even to fight diseases such as AIDS.

The world’s population is projected to jump to 9 billion by 2050, with more than 90 percent of that growth coming from developing countries.

It’s not the first time lifestyle issues have been tied to the battle against global warming. Climate change experts have previously recommended that people cut their meat intake to slow global warming by reducing the numbers of animals using the world’s resources.

The Lancet editorial cited a British report which says family planning is five times cheaper than usual technologies used to fight climate change. According to the report, each $7 spent on basic family planning would slash global carbon dioxide emissions by more than 1 ton.

Experts believe that while normal population growth is unlikely to significantly increase global warming that overpopulation in developing countries could lead to increased demand for food and shelter, which could jeopardize the environment as it struggles with global warming.

via Birth control could help combat climate change – Yahoo! News.

Exercise can extend survival even in ‘oldest old’

Even in the “oldest old,” a little physical activity goes a long way, extending life by at least a few years for people in their mid- to late 80s, Israeli researchers found.

The three-year survival rate was about three times higher for active 85-year-olds compared with those who were inactive. Getting less than four hours of exercise weekly was considered inactive; more than that was active.

The results “clearly support the continued encouragement of physical activity, even among the oldest old. Indeed, it seems that it is never too late to start,” the researchers wrote in Monday’s Archives of Internal Medicine, which published the study.

They noted that exercise reaped benefits even for previously sedentary 85-year-olds; their three-year survival rate was double that of inactive 85-year-olds.

Oldsters didn’t have to be super-athletes to live longer; walking at least four hours weekly counted, even if it was just in 15-minute strolls a few times daily.

“As little as four hours a week was as beneficial as more vigorous or prolonged activity,” said study author Dr. Jeremy Jacobs, a geriatric specialist at Hadassah Hebrew University Medical Center in Jerusalem.

Active octogenarians also reported less depression and loneliness and a greater ability to perform daily tasks.

Similar benefits have been shown in people in their 60s and 70s, but there has been little research about exercise benefits in people in their 80s.

The study involved 1,861 Jerusalem residents who were 70 years old in 1990. Participants filled out questionnaires about their health and activity levels through 2008.

At age 85, 64 percent were physically active, a relatively high percentage that reflects the Israeli lifestyle, Jacobs said. But he said similar benefits from exercise likely would be seen among the very old in other countries.

There were 512 deaths. Slightly fewer than 7 percent of the active 85-year-olds died by age 88, versus about 24 percent of those who were inactive.

via Exercise can extend survival even in ‘oldest old’ – Yahoo! News.

I’ve got to get back to the gym.

Nuke agency says Iran can make bomb – Yahoo!

Iran experts at the U.N.’s nuclear monitoring agency believe that Tehran has the ability to make a nuclear bomb and worked on developing a missile system that can carry an atomic warhead, according to a confidential report seen by The Associated Press.

The document drafted by senior officials at the International Atomic Energy Agency is the clearest indication yet that those officials share Washington’s views on Iran’s weapon-making capabilities and missile technology — even if they have not made those views public.

The document, titled “Possible Military Dimension of Iran’s Nuclear Program,” appeared to be the so-called IAEA “secret annex” on Iran’s alleged nuclear arms program that the U.S., France, Israel and other IAEA members say is being withheld by agency chief Mohamed ElBaradei — claims the nuclear watchdog denies.

It is a record of IAEA findings since the agency began probing Iran’s nuclear program in 2007 and has been continuously updated.

Calls to the Iranian mission at the United Nations were not immediately returned.

The information in the document that is either new, more detailed or represents a more forthright conclusion than found in published IAEA reports includes:

• The IAEA’s assessment that Iran worked on developing a chamber inside a ballistic missile capable of housing a warhead payload “that is quite likely to be nuclear.”

• That Iran engaged in “probable testing” of explosives commonly used to detonate a nuclear warhead — a method known as a “full-scale hemispherical explosively driven shock system.”

• An assessment that Iran worked on developing a system “for initiating a hemispherical high explosive charge” of the kind used to help spark a nuclear blast.

In another key finding, an excerpt notes: “The agency … assesses that Iran has sufficient information to be able to design and produce a workable implosion nuclear device (an atomic bomb) based on HEU (highly enriched uranium) as the fission fuel.”

ElBaradei said in 2007 there was no “concrete evidence” that Iran was engaged in atomic weapons work — a source of friction with the United States, which has sought a hard-line stance on Tehran’s nuclear ambitions.

Responding to the AP report, the agency did not deny the existence of a confidential record of its knowledge and assessment of Iran’s alleged attempts to make nuclear weapons. But an agency statement said the IAEA “has no concrete proof that there is or has been a nuclear weapon program in Iran.”

via AP NewsBreak: Nuke agency says Iran can make bomb – Yahoo! News.

Smaller T. rex discovered

This undated handout illustration provided by the journal Science shows a Raptorex. Weighing as little as 1/100th of its descendant T.Rex, Raptorex shows off its distinctive body plan of this most dominant line of predatory dinosaurs. About 125 million years ago a tiny version of Tyrannosaurus rex roamed what is now northeastern China. Tiny, that is, by T. rex standards — you still wouldn’t want to meet it face to face. Described by paleontologist Paul Sereno as ‘punk size,’ this early predator stood about 9 feet tall. It just seems small compared to the giant T. rex that evolved millions of years later and was as much as 100 times more massive.
via Smaller T. rex discovered – Yahoo! News Photos.

That little Raptorex skull with all the holes is really freaky. Makes me think it had more than two eyes!!! Yikes.