Thursday, November 20, 2014

Shedding UV light on skin color

For a long time it was believed that dark complexion evolved to protect humans from skin cancer. However, this theory has a flaw: melanoma typically is contracted after the reproductive age. Hence, the traditional theory for complexion cannot be correct because melanoma does not impact evolution.

Recently Nina Jablonski has hypothesized that like chimpanzees, our ancient ancestors in Africa originally had fair skin covered with hair. When they lost body hair in order to keep cool through sweating, perhaps about 1.5 million years ago, their naked skin became darker to protect it from folate-destroying UV light.

Variation in complexion may have evolved to protect folate from UV irradiation

Neural tube birth defects such as spina bifida are linked to deficiencies in folate, a naturally occurring form of vitamin B; Nina Jablonski learned that sunlight can destroy folate circulating in the tiny blood vessels of the skin. Furthermore, lower vitamin D weakens the immune response to the mycobacterium that causes tuberculosis. With this there is a strong evolutionary explanation for complexion variation.

If you live in a Silicon Valley hacker dojo or wear a burka, do not forget your vitamin B pills!

Read the article in Science 21 November 2014: Vol. 346 no. 6212 pp. 934-936 DOI: 10.1126/science.346.6212.934

Friday, November 7, 2014

Sharp has developed a reflective liquid crystal display panel for wearable computer devices, such as smart-watches, that consumes 0.1% the energy of current backlit panels. The Japanese electronics maker will mass-produce the panel in Japan by next spring and ship it to device makers domestically and abroad.

The panels incorporate memory chips and can save power on retrieving data by storing images for a certain amount of time. Panels account for more than 30% of the power usage of current wearable devices. With the new model, devices will be able to function for 30% longer before recharging.

Nikkei Asian Review, 31 October 2014