The JACS report describes development and successful testing of a photoswitch composed of the light-sensitive material, dithienylethene. The scientists grew transparent, pinhead-sized worms (C. elegans) and fed them a dithienylethene. When exposed to ultraviolet light, the worms turned blue and became paralyzed. When exposed to visible light, the dithienylethene became colorless again and the worms' paralysis ended. Many of the worms lived through the paralyze-unparalyze cycle. Scientists were not sure how the switch causes paralysis. The study demonstrates that photoswitches may have great potential in turning photodynamic therapy on and off, and for other applications in medicine and research, they indicate.

Abstract in Journal of American Chemical Society: A Photocontrolled Molecular Switch Regulates Paralysis in a Living Organism

Full story: New on-off 'switch' triggers and reverses paralysis in animals with a beam of light ...

A tidbit from the article:

However, trying to address the question of a shortage of cadavers often means facing the taboo on trading human anatomical goods (Delmonico et al. 2002; Scheper-Hughes 2000; Steiner 2006; Titmuss 1971). Blood, organs, and cadavers are generally thought to be better left untouched by market dynamics. Their sacredness sets them apart from other traded goods. As Philippe Steiner recently reminded us in this newsletter, he began researching organ donation because of the stringency of the ban on market transactions for organs (Steiner 2009). In essence, many would argue that blood, organs, and cadavers should not be considered goods.

That said, the demand for cadavers remains strong, and numerous ideas have been voiced to augment the supply. As an illustration, there is an ongoing debate about the impact of using financial incentives for donors or their families to encourage anatomical donations (Clay and Block 2002; Delmonico et al. 2002; Harrington and Sayre 2006; Obermann 1998). Similarly, surveys of potential whole-body donors seek to gain insight into the reluctance to donate and how better to educate potential donors (Boulware et al. 2004; Richardson and Hurwitz 1995; Sanner 1994). By understanding the reluctance to donate, the hope is that the root causes of such reluctance might be addressed.

We recall that Howard Stern once ran a "cadaverothon" on his radio show when news came out that Yale and Harvard med schools were running low on bodies.

Link: A Market for Human Cadavers in All but Name?

(hat tip: WSJ Health Blog)

From the statement by the American Heart Association:

Researchers used a metabolic chamber to measure the energy expenditure of 12 men and women, 25 to 44 years old, as they pantomimed basic moves and motions of these sports and physical activities with motion-sensing controls. The open-circuit indirect metabolic chamber consisted of an airtight room (20,000 liters or 15,000 liters). The metabolic chamber method could replicate the conditions under which the participants enjoy the games in their home, because they were free from apparatus used to measure energy expenditure (EE) when playing the game.

Researchers found:

Nine activities had less than 2 METs.

Twenty-three activities had 2-3 METs.

Nine activities had 3-4 METs.

Five activities had more than 4 METs.

The intensities of yoga and balance exercise were significantly lower than those of resistance and aerobic exercise, but these exercises are effective in improving flexibility and in fall prevention, researchers said.

More from AHA: Playing active video games can equal moderate-intensity exercise ...

The team used sponge-like microparticles, designed by the laboratory of Tarek Fahmy, associate professor of biomedical engineering at Yale, that mimicked bacteria by slowly releasing a characteristic bacterial “scent.” They then moved these microparticles using focused beams of light to control the pattern of released chemicals over space and time, stimulating the immune cells to respond. The neutrophils can be seen following the microparticles on videos produced by the researchers.

“By fusing recent advances in optical and materials science, we’ve developed a new approach to control chemical microenvironments with light,” said Dufresne, who developed holographic optical tweezers – the underlying technology used to manipulate the microparticles – in the late 1990s. “Until now, people have used optical tweezers to move physical objects. We’ve demonstrated that they can also be used to manipulate chemical gradients.”

The team used two different chemicals, one of which attracted the cells and another that repelled them, to demonstrate how they could direct the neutrophils into moving along a path, either toward or away from the microparticles. They could also examine how the cells responded when there were conflicting signals sent by several of the artificial bacteria.

Yale statement: Scientists Guide Immune Cells with Light and Microparticles ...

Abstract in Nature Methods: Cell stimulation with optically manipulated microsources

Link @ Gizmodo: Your Next Body Is Growing In a Lab Right Now

Image: 3D matrix being populated with human bladder cells.

The transfer of a positively-charged hydrogen atom – a bare proton – along a reaction chain in GFP generates a green flash of light. The laser snapshots show that when the light absorber, or chromophore, nestled in the middle of the protein barrel absorbs an incoming photon of blue light, it starts vibrating, and the electrons start sloshing around the chromophore until it is aligned just right for the proton to hop via a water molecule to a nearby amino acid in the protein. From there, it continues down the reaction chain, creating a state with a negatively charged chromophore that emits green light.

Previous studies had shown that after the chromophore absorbs blue light, it undergoes proton transfer, and green light is emitted. In the current study, Mathies, Fang and their colleagues could actually resolve the early stage of this proton transfer reaction, taking snapshots of the vibrational wagging of the chromophore skeleton in sync with the electron cloud in the chromophore sloshing back and forth. However, the wagging oscillation might have stopped after a few picoseconds, when the chromophore and its vicinity are aligned just right for the proton to hop off down the reaction chain, and the whole protein shines bright green – which it does in its own good time, in about 3 nanoseconds.

Femtosecond stimulated Raman spectroscopy on GFP involves hitting the protein molecule with an approximately 80 femtosecond pulse of ultraviolet light, which excites many vibrational modes in the molecule, and then a one-two punch of picosecond red and femtosecond white light to stimulate Raman emission. The spectrum of emitted signals tells researchers the vibrational modes of various parts of the molecule. If the molecule is in the middle of a reaction, the emitted light at different time delays tells the researcher the various steps the molecule goes through during the reaction.

Berkeley Lab press release: Vibrations key to efficiency of green fluorescent protein ...

Abstract in Nature: Mapping GFP structure evolution during proton transfer with femtosecond Raman spectroscopy

MIT Technology Review explains:

Under their plan, a device will always be accessible from up to 10 meters away, and will normally enforce a series of authentication steps before allowing access. In an emergency, however, when the device detects that the patient using it is in trouble, it will grant access to anyone who is physically close to the patient (within about three centimeters).

Other researchers have suggested requiring wireless reading devices to be physically close to an implant in order to access it. But Castelluccia says that attackers can get around this by using a strong radio transmitter to mimic close proximity. To solve this issue, his plan calls for ultrasound waves to be used in addition to radio signals--the speed of sound allows the device to calculate with confidence how far away the reader is.

Castelluccia says the device only needs a microphone in order to detect the ultrasound and that he doesn't expect the protocol to consume much power--a key concern with an implantable medical device because it's hard to replace the battery. Because the device won't respond to requests that come from outside the predetermined distance, it would also be harder for an attacker to wear down the battery by forcing it to process one request after another.

More from Technology Review...

Looking at the structure of GCaMP2, Looger could see exactly how the molecule grabbed on to calcium and turned this into brighter fluorescence. It did not take long before he and his team roughed out ideas for making modifications to the molecule that would make it grab calcium more tightly. They also identified a second set of modifications would make the molecule glow more brightly. Looger’s team made those adjustments and wound up with GCaMP3, which he says is three times brighter, three times more sensitive to calcium, and binds the calcium 1.3 times more tightly than GCaMP2.

With the new indicator in hand, Looger collaborated with Janelia Farm fellow Vivek Jayaraman to test GCaMP3’s power to track the activity of a single neuron in the fruit fly brain. “The tiny size of the fruit fly brain makes recording from its neurons with electrodes exceedingly hard,” explains Jayaraman. “GCaMP3 provides a non-invasive way to measure the activity of specific neurons with a bright signal that is unprecedented for such sensors.” Jayaraman says his research group uses the tool for their studies of the neural circuitry that guides visual processing.

GCaMP3 also proved useful in revealing neural activity in another popular animal model, the flatworm C. elegans. Cornelia Bargmann’s lab at Rockefeller genetically engineered worms that expressed the new calcium indicator in a neuron known to detect odors, and watched that neuron light up as certain smells were presented and taken away. The increase in fluorescence when the neuron fired was far more dramatic than the team saw with earlier generation GCaMPs.

Looger also collaborated with Janelia group leader Karel Svoboda to use GCaMP3 for imaging brain activity in the mouse. They engineered mice that produced GCaMP3 in a group of neurons that processes information from just one of the animal’s whiskers. They were able to watch 13 neurons within that group light up in a particular sequence as the mouse walked and the whisker moved.

Video and links are after the jump:

(hat tip: Richard Dawkins)

The final 100 to 150 milliseconds of the cough contains the distinctive sounds that could help doctors and nurses remotely diagnose a cough as the common cold or more serious pneumonia.

Even with a limited amount of data, scientists can distinguish between a healthy, voluntary cough and the involuntary cough of a sick person. Healthy people have slightly louder coughs, about 2 percent louder than a sick person.

After the initial burst of sound, a cough becomes increasingly complex. The vocal cords vibrate. Mucus in the lungs, throat and nose absorb certain wavelengths while emitting their own noises. Most of this mucousal music emerges from the mouth, but some of it also comes from head, neck and chest.

If a doctor already has a disease diagnosis, the sound of a cough could contain clues about how much fluid has built up in a patient's lungs.

Before a definitive diagnose of cold or flu over the phone can be achieved, the scientists need more data. So far the scientists have gathered cough records from several dozen sick patients from a local hospital's emergency department.

Full story @ DiscoveryNews: Cough Into Your Cell Phone, Get Diagnosis...

STAR Analytical Services press release: STAR Analytical Services Receives $100,000 Grand Challenges Explorations Grant for Innovative Global Health Research...

Company homepage: STAR Analytical Services ...

(Image: courosa)