Neuron Traffic moving through a cell - YouTube

Video depicting the flow of transport vesicles containing NgCAM, using a 16-color filter. Here, the intensity of the pixels (and thus protein concentration) varies from white (very high) to purple (very low). (Courtesy of Don Arnold and Sarmad Al-Bassam)

Using bioluminescent proteins from a jellyfish, scientists have lit up the inside of a neuron and captured footage of proteins moving throughout the cell.

The video offers a rare peek at how proteins, the brain’s building blocks, are directed through neurons to renew its structure.

“Your brain is being disassembled and reassembled every day,” says Don Arnold, associate professor of molecular and computational biology at University of Southern California (USC), and corresponding author of an article about the research published in Cell Reports.

“One week from today, your brain will be made up of completely different proteins than it is today,” Arnold says. “This video shows the process. We’ve known that it was happening, but now we can watch it happen.”

All-seeing Ball Camera snaps panoramas in mid-air

Throw a typical camera in the air and you're unlikely to capture anything stunning. But now a new ball-shaped camera, created by Jonas Pfeil from the Technical University of Berlin and colleagues, is designed to be tossed upwards to snap panoramas in mid-air.

The rubber ball, which contains 36 cellphone cameras, barely moves at the highest point of its trajectory so the photos it captures aren't blurred by movement.

A built-in accelerometer measures in-flight speed to detect this stationary point and trigger the cameras. Software then stitches the pictures together into a spherical panoramic image.

The team developed the system to simplify panoramic photography, which normally involves painstakingly connecting several different images.

The ball will be demonstrated at Siggraph Asia, a conference on computer graphics and interactive techniques, from December 13-15 in Hong Kong.

Illuminating the 'Dark Matter' of the Genome: Vast hidden network regulates gene expression in cancer

Researchers have uncovered a vast new gene regulatory network in mammalian cells that could explain genetic variability in cancer and other diseases.

(Credit: Image courtesy of Columbia University Medical Center)

Researchers at Columbia University Medical Center (CUMC) and two other institutions have uncovered a vast new gene regulatory network in mammalian cells that could explain genetic variability in cancer and other diseases.

The studies appear in the online edition of Cell.

"The discovery of this regulatory network fills in a missing piece in the puzzle of cell regulation and allows us to identify genes never before associated with a particular type of tumour or disease," said Andrea Califano, PhD, professor of systems biology, director of the Columbia Initiative in Systems Biology, and senior author of the CUMC research team.

For decades, scientists have thought that the primary role of messenger RNA (mRNA) is to shuttle information from the DNA to the ribosomes, the sites of protein synthesis.

However, these new studies suggest that the mRNA of one gene can control, and be controlled by, the mRNA of other genes via a large pool of microRNA molecules, with dozens to hundreds of genes working together in complex self-regulating sub-networks.

The findings have the potential to broaden investigations into how tumors develop and grow, who is at risk for cancer, and how to identify and inactivate key molecules that encourage the growth and spread of cancer.

For example, in the case of the phosphatase and tensin homolog gene (PTEN), a major tumour suppressor, deletions of its mRNA network regulators in patients appear to be as damaging as mutations of the gene itself in several types of cancer, the studies show.

The newly identified regulatory network (called the mPR network by the CUMC investigators) allows mRNAs to communicate through small bits of RNA called microRNAs.

Researchers first realized about a decade ago that microRNAs, by binding to complementary genetic sequences on mRNAs, can prevent those mRNAs from making proteins.

Turning this concept on end, the new studies reveal that mRNAs actually use microRNAs to influence the expression of other genes.

When two genes share a set of microRNA regulators, changes in expression of one gene affects the other. If, for instance, one of those genes is highly expressed, the increase in its mRNA molecules will "sponge up" more of the available microRNAs.

As a result, fewer microRNA molecules will be available to bind and repress the other gene's mRNAs, leading to a corresponding increase in expression. Although such an effect had been previously elucidated, the range and relevance of this kind of interaction had not been characterised.

"It turns out that this type of microRNA-mediated regulation is commonplace in the cell, and thousands of genes are regulating one another through hundreds of thousands of microRNA-mediated interactions," says Pavel Sumazin, PhD, research scientist in systems biology and a first author of the CUMC paper.

"This is similar in size and effect to other regulatory networks, such as transcriptional regulatory networks, where target genes are regulated by transcription factors."

In the CUMC study, Dr. Sumazin and his colleagues analyzed glioblastoma mRNA and microRNA expression data from the Cancer Genome Atlas, a public database, uncovering a regulatory layer comprising more than 248,000 microRNA-mediated interactions.

Looking specifically at the tumour suppressor gene PTEN, the researchers found that it is part of a sub-network of more than 500 genes.

Of these genes, 13 are frequently deleted in glioblastoma and seem to work together through microRNAs to stop PTEN activity -- achieving the same result as if the tumors had inactivating mutations or deletions of PTEN itself.

Read More on this article at Science Daily

MIT generates photovoltaic power without sunlight

With heat, tungsten, and a silicon cell, MIT researchers have been developing a different way to get power from photovoltaics without sunlight.

Photovoltaic cells work best with light hitting them at certain wavelengths.

Ultra-violet and infrared waves, for instance, can be tough for semiconductors to absorb in order to generate electricity. But engineers at MIT have designed a system that converts heat into specific light wavelengths, custom fit for a solar cell. And possibly, custom fit for miniature electronics as well.

Such thermo-photovoltaic systems have been around for a while, but they haven’t performed as efficiently as the silicon chip “micro-reactors” described recently in the journal Physical Review A. Etching a pattern of nanoscopic pits and ridges into a bit of tungsten, the researchers created a thermal material that can partner up with a photovoltaic cell to absorb more light radiation.

The tungsten heats up and glows, with the design on its surface controlling the way light behaves. According to the study, the sculpted pits act resonators, emitting light with wavelengths best suited for uptake by the PV cell.

Need a recharge? Just add heat. This could come from the sun but doesn’t have to. For the study, the engineering team used the hydrocarbon butane. So in the future, butane might power more things in your pocket than your cigarette lighter.

They also developed a device that could draw heat from a decaying radioisotope. With such a heat source, years could pass between recharges. The researchers have long, dark space missions in mind.
Co-author Ivan Celanovic says in MITnews:

Being able to convert heat from various sources into electricity without moving parts would bring huge benefits, especially if we could do it efficiently, relatively inexpensively and on a small scale.

The silicon chip micro-reactors are shown above without PV cells attached to their sides. According to Celanovic, the devices are three times as efficient as lithium-ion batteries of similar size and weight. Yet the research team isn’t stopping there. They hope to one day triple even that

Fluxcapacitor is back in the future

A supercapacitor – a device that can unleash large amounts of charge very quickly – has been created using printing technology for the first time. The advance will pave the way for "printed" power supplies that could be useful as gadgets become thinner, lighter and even flexible.

Advances in electronics mean portable gadgets are shrinking in size but growing in their energy demands, and conventional batteries are struggling to cope.

Batteries are slow to recharge because they store energy chemically. By contrast, capacitors, which are common in electronics, are short-term stores of electrical energy that charge almost instantaneously but hold little energy.

In recent years capacitors able to store thousands of times as much energy as standard ones, called supercapacitors, have been developed. They are charged by applying a voltage to two electrodes suspended in a solution so that positive ions head to one electrode and negative ions to the other.

Now, a team led by George Grüner at the University of California, Los Angeles, has printed a supercapacitor for the first time, building on earlier theoretical work to provide quick bursts of power that today's electronics devices demand.

Team members sprayed carbon nanotubes onto a plastic film – two such films act as both the device's electrodes and charge collectors. Between the two films, the team sandwiched a gel electrolyte made by mixing a water-soluble synthetic polymer with phosphoric acid and water.

It's a Capacitor Jim, but not as we know it!