A solar fuel device has been developed that can store nearly 5 per cent of solar energy in the form of hydrogen. Photosynthesis, a process that uses sunlight to split water into hydrogen and oxygen, allows storage of solar energy as hydrogen.
This hydrogen can then be used as a fuel or be used in a fuel cell to generate power. The new device can perform artificial photosynthesis using a simple solar cell and a photo anode made of bismuth vanadate. It is cost-effective, highly stable and highly efficient. Nature, July 29
Ring of trouble
Cell phones can cause cancer and using one for just 17 minutes a day dramatically increases the risk. This is the finding of a study that analysed saliva of cell phone users to explore the link between cancer and cell phones. Saliva was considered a good indicator since the gadget is placed close to the salivary gland when in use.
It was found that cells of the saliva of heavy mobile users show products related to high oxidative stress, a process that damages cells and leads to cellular and genetic mutations that cause cancerous tumours. Antioxidants & Redox Signaling, July 16
How plants set the angle of their branches has long been a mystery. It has now been found that an anti-gravity mechanism in branches, known as the ‘anti-gravitropic offset’ (AGO), is responsible for this. AGO counteracts the normal gravity responsive growth in the lateral branches and prevents them from being moved beyond a set angle to the vertical. This growth is also driven by auxin, the same hormone that causes gravity responsive growth in plants. Plants that grow upright have a weak AGO, while those with branches spreading outwards have stronger AGO. These insights can help optimise yields by providing ways to improve crops by altering plant architecture. Current Biology, July 25
Nearly 50 per cent of Europe’s grassland butterflies have disappeared between 1990 and 2011 due to habitat loss, intensifying agriculture and a mismanagement of grassland ecosystems. Eight of the 17 butterfly species that were the focus of the study have showed declines. The finding has worried environmentalist because butterflies play a key role in pollination and are considered to be representative indicators of biodiversity and the general health of ecosystems. PNAS, July 25
Climate change is not the only threat to polar bears. It has been found that environmental toxins are crossing the blood-brain barrier and seeping into the brain tissue of these mammals. PerFluoroAlkyl Substances (PFASs), the toxins that have been found in polar bears in the Arctic, are present in everyday items like Teflon pans and textile coatings. They are non-degradable. When a small fish eats the chemical, and is then eaten itself, the toxin travels up the food chain, eventually arriving in polar bear habitats. The chemicals can damage the brain, liver and reproductive system. Environmental Toxicology and Chemistry, July 20
Blame it on moon
Urban legend that full moon interferes with everything from moods to sleep might not be entirely baseless. It has been found that people do get less and lower quality sleep around the time of full moons.
Sleep analysis of over 30 volunteers during a full moon showed that subjects took five minutes longer to fall asleep, slept for 20 minutes lesser than normal and their deep sleep period decreased by about 30 per cent compared to sleep during a new moon. They also felt less rested during the full moon and had lower levels of melatonin, the hormone that helps regulate the sleep cycle. This is the first reliable evidence that lunar rhythm can modulate sleep in humans. Current Biology, July 25
As gadgets become smaller, heat management becomes a bigger problem. Heat transfer materials are, therefore, used to keep sensitive electronics cool. So far diamond is considered the best heat transfer material. It, however, is rare and expensive. It has now been found that cubic boron arsenide is capable as high heat transfer as diamond. The finding gives important insight into the physics of thermal transport in materials and could help develop cheap and efficient heat sinks for electronic devices. Physical Review Letters, July 8
Not so old
Martian meteorites found on Earth could be much younger than thought, meaning that Mars could still be geologically active. A new technique using isotopic and micro-structural analysis to determine the age of rocks has shown that a meteorite that fell on Earth was created about 200 million years ago from an ancient Martian lava flow. Traces of crystals created during the ejection of the rock from Mars show the event must have occurred 20 million years ago. Previously it was thought Martian rocks could be up to 4,000 million years old. The finding paints a much clearer picture of the Red Planet’s evolution. Nature, July 24 (online)
Oil palm plantations have devastated forest land and rain forests across many parts of the world. But this might change as the genome of this key commercial crops has been sequenced. The genetic make-up of the plant has revealed that a single gene, known as Shell, is responsible for improving the plant’s yield of oil by 30 per cent. Manipulating this gene could not only help increase oil yield from palm plantations but also reduce palm oil industry’s pressure on rainforests across the globe as less acreage would be needed to produce the same amount of palm oil as before. The plant’s oil is used in many food and household products. Nature, July 24 (online)
Rising carbon dioxide levels in the atmosphere over the past three decades are making deserts greener through a process called CO2 fertilisation. It occurs when elevated levels of CO2 enable a leaf to extract more carbon from the air, lose less water to the air, or both. This, in turn, causes the plant to be healthier and to be able to overcome harsher conditions. Satellite observations of the world’s arid regions from 1982 to 2010 show that 11 per cent increase in green cover across parts of Australia, North America, the Middle East and Africa is linked to CO2 fertilisation. Geophysical Research Letters, June 19
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