Like hobos on a train, HIV, the virus that causes AIDS, uses a pre-existing transport system to leave one infected cell and infect new ones, Hopkins scientists have discovered. Their findings, published in the June issue of Plos Biology, counter the prevailing belief that HIV and other retroviruses can only leave and enter cells by virus-specific mechanisms.

In head-to-head trials of two drugs, the one deemed better appears to depend largely on who is funding the study, according to an analysis of nearly 200 statin-drug comparisons carried out between 1999 and 2005.

UCSF researchers examined 192 published results of trials comparing one cholesterol-lowering statin drug to another, or to a non-statin drug.

Radical steps to engineer Earth’s climate by blocking sunlight could drastically cool the planet, but could just as easily worsen the situation if these projects fail or are suddenly halted, according to a new computer modeling study.

The experiments, described in the June 4 early online edition of The Proceedings of the National Academy of Sciences, look at what might happen if we attempt to slow climate change by “geoengineering” a solar filter instead of reducing carbon dioxide emissions. The researchers used a computer model to simulate a decrease in solar radiation across the entire planet, but assumed that that the current trend of increasing global carbon dioxide emissions would continue for the rest of this century.

Commonly used by around 10 million people in east Africa and countries in the Arabian peninsula, chewing khat for its stimulant properties has also become popular in the UK among immigrants of the Somali, Yemeni and Ethiopian communities. Whilst it is reported to have cultural functions, it is also increasingly reported to be associated with social and medical problems including anti-social behaviour, unemployment, psychoses, depression, and self-neglect.

The Huygens Atmosphere Structure Instrument (HASI) scored a first in 2005 by measuring the electrical conductivity of Titan’s atmosphere. The results hint at a new way to investigate the subsurface layers of Titan and could provide insight into whether or not Titan has a subsurface ocean.

The Permittivity, Waves and Altimetry (PWA) sensor on Huygens detected an extremely low frequency (ELF) radio wave during the descent. It was oscillating very slowly for a radio wave, just 36 times a second, and increased slightly in frequency as the probe reached lower altitudes.

Discarded crab and lobster shells may be the key to prolonging the life of microbial fuel cells that power sensors beneath the sea, according to a team of Penn State researchers.

To produce energy, microbial fuel cells need organic material for the microbes to consume. However, deep sea sediments can be surprisingly devoid of organic material because living things in the photic zone – the area where light penetrates the water – are continuously recycled and little falls to the ocean floor. An absence of organics limits the lifetime of marine microbial fuel cells.