Daily Magazine

Most of us need seven to eight hours of sleep a night to function well, but some people seem to need a lot less sleep. The difference is largely due to genetic variability. In research published online June 18th in Current Biology, researchers report that two genes, originally known for their regulation of cell division, are required for normal slumber in fly models of sleep: taranis and Cyclin-dependent kinase 1 (Cdk1).

'There's a lot we don't understand about sleep, especially when it comes to the protein machinery that initiates the process on the cellular level,' says Kyunghee Koh, Ph.D., assistant professor of Neuroscience at the Farber Institute for Neurosciences at Thomas Jefferson University and senior author on the study. 'Our research elucidates a new molecular pathway and a novel brain area that play a role in controlling how long we sleep.'

The researchers examined thousands of mutant fly lines and found a mutant, called taranis, that slept a lot less than normal flies. Using a series of genetic and biochemical experiments, the researchers tracked how Taranis interacted with other proteins and saw that Taranis bound to a known sleep regulator protein called Cyclin A. Their data suggest that Taranis and Cyclin A create a molecular machine that inactivates Cdk1, whose normal function is to suppress sleep and promote wakefulness.

Previous research has shown that Cyclin A is expressed in a small number of neurons including a cluster of seven neurons on each side of the brain. Koh and colleagues showed that these neurons are located in an area of the fly brain that corresponds with the human hypothalamus -- one of the sleep centers of the human brain. They saw a reduction of overall sleep when Taranis was knocked down only in these 14 neurons and when these same neurons are activated. 'We think this may be an arousal center in the fly brain that Taranis helps inhibit during sleep,' says Koh.

Although the Taranis protein has a human cousin, called the Trip-Br family of transcriptional regulators, it is yet unclear whether a similar system is at play in humans. However, Dr. Koh and her team first plan to investigate the cues that turn Taranis on and which proteins the Cdk1 kinase acts on to prevent sleep.

Via Dr. Stefan Gruenwald, Sigalon

For years, the most important food technologies were all about scale. How could we feed a fast-growing population at less expense? By doing everything bigger: food grown on bigger farms was sold by ever-merging global food giants to grocery chains of superstore proportions.

Many of today’s food technologies seem to be moving in the opposite direction, toward methods and products that are economical for small farms as well as large corporate ones. This does not mean an end to big food: with the planet’s population projected to reach 9.6 billion by 2050, agriculture and food production will still have to achieve a massive scale, with help from technology and innovative research. Still, evolving technologies, including inexpensive sensors, mobile devices, and data analysis, have helped an increasing variety of food companies, retailers, and producers lower their costs and compete in many specialty markets.

This could be the start of a new food economy—one that reflects more competition and more innovation, provides opportunity for a broader group of investors, and is more dynamic and responsive than the industrial model that has dominated for decades.

Via Sigalon

A new technology developed by chemists at UCLA is capable of storing solar energy for up to several weeks. 

The materials in most of today’s residential rooftop solar panels can store energy from the sun for only a few microseconds at a time. A new technology developed by chemists at UCLA is capable of storing solar energy for up to several weeks — an advance that could change the way scientists think about designing solar cells.

The findings are published June 19 in the journal Science. The new design is inspired by the way that plants generate energy through photosynthesis.

“Biology does a very good job of creating energy from sunlight,” said Sarah Tolbert, a UCLA professor of chemistry and one of the senior authors of the research. “Plants do this through photosynthesis with extremely high efficiency.”

“In photosynthesis, plants that are exposed to sunlight use carefully organized nanoscale structures within their cells to rapidly separate charges — pulling electrons away from the positively charged molecule that is left behind, and keeping positive and negative charges separated,” Tolbert said. “That separation is the key to making the process so efficient.”

To capture energy from sunlight, conventional rooftop solar cells use silicon, a fairly expensive material.  There is currently a big push to make lower-cost solar cells using plastics, rather than silicon, but today’s plastic solar cells are relatively inefficient, in large part because the separated positive and negative electric charges often recombine before they can become electrical energy.

“Modern plastic solar cells don’t have well-defined structures like plants do because we never knew how to make them before,” Tolbert said. “But this new system pulls charges apart and keeps them separated for days, or even weeks. Once you make the right structure, you can vastly improve the retention of energy.”

The two components that make the UCLA-developed system work are a polymer donor and a nano-scale fullerene acceptor. The polymer donor absorbs sunlight and passes electrons to the fullerene acceptor; the process generates electrical energy.

The plastic materials, called organic photovoltaics, are typically organized like a plate of cooked pasta — a disorganized mass of long, skinny polymer “spaghetti” with random fullerene “meatballs.” But this arrangement makes it difficult to get current out of the cell because the electrons sometimes hop back to the polymer spaghetti and are lost.

The UCLA technology arranges the elements more neatly — like small bundles of uncooked spaghetti with precisely placed meatballs. Some fullerene meatballs are designed to sit inside the spaghetti bundles, but others are forced to stay on the outside.  The fullerenes inside the structure take electrons from the polymers and toss them to the outside fullerene, which can effectively keep the electrons away from the polymer for weeks.

Via Dr. Stefan Gruenwald, Sigalon