The "female sex hormone" estradiol is present in both men and women, and is generated from testosterone in men by the protein aromatase.
Estradiol plays various roles in addition to its gender-specific ones, including having effects on the hearing (auditory) system. In a new study, Barbara Canlon and colleagues at the Karolinska Institute in Stockholm, Sweden, investigated the role of estradiol-binding proteins, known as estrogen receptors, in response to auditory damage by examining hearing loss recovery in mice with deficiencies in various estrogen receptors.
Ski tourism raises stress levels among capercaillie and could harm the birds’ fitness and ability to breed successfully, write ecologists in the Journal of Applied Ecology. They warn that forests should be kept free from tourism if they are inhabited by capercaillie - a species whose numbers are declining markedly across central Europe.
The study by ecologists from Switzerland, Germany and Austria used a new technique to assess the impact of ski tourism on capercaillie. Working in the Southern Black Forest in Germany, they collected the birds’ droppings before and after the start of the ski season, and analysed them for levels of the breakdown products of the stress hormone corticosterone.
Adult stem cells may provide an explanation for the cause of a Hutchinson-Gilford Progeria Syndrome (HGPS), a rare disease that causes premature aging in children, according to researchers at the National Cancer Institute. These findings, the first to indicate a biological basis for the clinical features of HGPS, also known as progeria, may also provide new insights into the biological mechanisms of normal aging.
“Studies like this of the biology of HGPS hold the potential to benefit children suffering this terrible illness and enlighten us as to the medical changes we all experience as we grow older.” said NCI Director John E. Niederhuber, M.D. “As our population ages, we have an increasing need for greater understanding of the biology of aging and age-related illness, such as cancer.”
An international team has achieved, by means of a controlled chemical process, that atoms of gold, silver and copper - intrinsically non-magnetic (not attracted to a magnet) - become magnetic.
According to the research, the magnetism appears reduce the dimensions of the material to nanometric dimensions and surround it with previously selected organic molecules. The magnetism of these nanoparticles is a permanent one (like iron) which, even at ambient temperature, is quite significant.
This amazing behavior has been obtained not just with gold (a phenomenon which had already been put forward as experimentally possible) but, in this research, nanoparticles of silver and copper (the atoms of which are intrinsically non-magnetic) with a size of 2 nm (0.000002 mm) have also been shown to be magnetic at ambient temperature.
Sometimes scientists won't understand it even after they see it, but at least they'll believe it despite its improbability. Such is the case with bats, the bumblebee and the hummingbird, which according to classic wing theory should not be able to fly. Yet they seem to have forgotten to read that textbook.
In 1995, bumblebee flight got its answer. This week, the aerodynamics of a hovering bat species has been revealed. Its flight was studied in the wind tunnel laboratory of Lund University.
The wind tunnel at Lund University is specially crafted for research on bird flight. Birds fly “at the spot” against a headwind, allowing detailed investigation of wing movements using high speed video cameras.
Narcolepsy is a sleep disorder that causes people to fall asleep uncontrollably during the day. It also includes features of dreaming that occur while awake. Other common symptoms include sleep paralysis, hallucinations and cataplexy. About one out of every 2,000 people is known to have narcolepsy. It affects the same number of men and women.
The majority of patients with narcolepsy/cataplexy experience a number of symptoms of eating disorders, with an irresistible craving for food and binge eating as the most prominent features, according to a study published in the March 1 issue of the journal SLEEP.