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Soon, wearable silicon solar-cell fabrics

An international team of chemists, physicists, and engineers has, for the first time, developed a silicon-based optical fibre with solar-cell capabilities that is capable of being scaled up to many metres in length. 

The research opens the door to the possibility of weaving together solar-cell silicon wires to create flexible, curved, or twisted solar fabrics.

The findings by the team led by John Badding, a professor of chemistry at Penn StateUniversity build on earlier work addressing the challenge of merging optical fibers with electronic chips -- silicon-based integrated circuits that serve as the building blocks for most semiconductor electronic devices such as solar cells, computers, and cell phones. Rather than merge a flat chip with a round optical fiber, the team found a way to build a new kind of optical fiber -- which is thinner than the width of a human hair -- with its own integrated electronic component, thereby bypassing the need to integrate fiber-optics with chips.

To do this, they used high-pressure chemistry techniques to deposit semiconducting materials directly, layer by layer, into tiny holes in optical fibers.

Now, in their new research, the team members have used the same high-pressure chemistry techniques to make a fiber out of crystalline silicon semiconductor materials that can function as a solar cell -- a photovoltaic device that can generate electrical power by converting solar radiation into direct-current electricity.

Asthma symptoms fluctuate during menstrual cycle

A new study has suggested that some women may have more or fewer asthma symptoms depending on where they are in their menstrual cycle.

Researchers said spikes and dips in oestrogen and other hormones likely affect the lungs and other physiological responses involved in breathing. However, it’s still unclear whether the findings could improve doctors’ treatment of women with asthma, News 24 reported.

Dr Ferenc Macsali of Haukeland University Hospital in Bergen, Norway, and colleagues surveyed close to 4 000 women in Northern Europe who had normal periods and weren’t taking birth control pills.

Along with other health and lifestyle questions, they asked women to report when their last period started, as well as whether they’d had any breathing-related problems in the past three days.

Just under 8 per cent had been diagnosed with asthma. Between 2 percent and 6 per cent reported recent wheezing, coughing and/or shortness of breath.

New light on Darwin’s abominable mystery

New research has shed new light on what Charles Darwin famously called "an abominable mystery": the apparently sudden appearance and rapid spread of flowering plants in the fossil record.

Indiana University paleobotanist David L. Dilcher and colleagues in Europe have presented a scenario in which flowering plants, or angiosperms, evolved and colonized various types of aquatic environments over about 45 million years in the early to middle Cretaceous Period.

The work is based on extensive fossil data from Europe and provides a comprehensive picture of how angiosperms evolved and connect their evolution with changes in the physical and biological environments.

Dilcher, who has studied the rise and spread of flowering plants for decades, said the scenario is consistent with findings from the fossil record in North America, including his own work showing that angiosperms occupied a variety of aquatic and near-aquatic environments.

"This attention to the total picture of plant groups and the paleo-environment begins to form a pattern. We're able to turn the pages of time with a little more precision," Dilcher said.

Darwin wrote to Joseph Dalton Hooker in 1879, about 20 years after the publication of "On the Origin of Species," that the rapid development of higher plants in recent geological times was "an abominable mystery."

The issue has long preoccupied paleobotanists, with competing theories seeking to explain howangiosperms supplanted ferns and gymnosperms in many regions of the globe.

 Dilcher and his colleagues show that angiosperms successfully invaded certain environments, gradually spreading to others.

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