Mars lander takes an image of Martian dust
PASADENA, Calif., Aug. 14 (UPI) -- The U.S. space agency says its Phoenix Mars Lander has used an atomic force microscope to take the first-ever image of a single particle of Mars' dust.
National Aeronautics and Space Administration scientists said the rounded particle has a diameter of about one micrometer, or one millionth of a meter, and is a speck of the dust that colors the Martian sky pink and its soil a distinctive red.
"This is the first picture of a clay-sized particle on Mars, and the size agrees with predictions from the colors seen in sunsets on the Red Planet," said Phoenix Lander co-investigator Urs Staufer of the University of Neuchatel, Switzerland, who leads a Swiss consortium that made the microscope.
NASA said the atomic force microscope can detail shapes of particles as small as about 100 nanometers, which is about 100 times greater magnification than seen with Phoenix's optical microscope.
Mars' ultra-fine dust is the medium that actively links gases in the Martian atmosphere to processes in Martian soil, so it is critically important to understanding that planet's environment, the researchers said.
Study: Earth's edible fish face extinction
WASHINGTON, Aug. 14 (UPI) -- A U.S. scientist predicts continued overfishing will lead to the extinction of the Earth's edible species of fish and affect other levels of the food chain.
But Jeremy Jackson, a senior scientist at the Smithsonian Tropical Research Institute and the Scripps Institution of Oceanography, says just the enforcement of fishery regulations would help prevent such extinctions.
Jackson says certain steps, if taken immediately, might reverse the demise of the Earth's ocean species. Those measures include establishing marine reserves, eliminating subsidies for fertilizer use and limiting fossil fuel consumption.
In addition to the extinction of edible fish species, he said without the immediate implementation of ocean-protection measures, larger dead zones and toxic algal blooms may form along the coastal zones of all of the world's continents, increasing disease outbreaks and inhibiting vertical mixing of ocean waters.
"Some may say that it is irresponsible to make such predictions pending further detailed study to be sure of every point," said Jackson. "However, we will never be certain about every detail, and it would be irresponsible to remain silent in the face of what we already know."
The study appears in the early online edition of the Proceedings of the National Academy of Sciences.
Genetic cause of colorectal cancer found
CHICAGO, Aug. 14 (UPI) -- U.S. medical scientists say they've discovered a genetic trait that is likely the most common cause of colorectal cancer that's been found.
Researchers at Northwestern University's Feinberg School of Medicine and colleagues say the genetic trait they discovered is present in 10 percent to 20 percent of patients with colorectal cancer. That, the scientists said, strongly suggests the trait is a major contributor to, and likely the most common cause of, colorectal cancer.
If a person inherits the trait -- which is dominant and clusters in families -- the scientists found the lifetime risk of developing colorectal cancer is 50 percent, compared with 6 percent for the general population.
"The reasonable expectation is this finding will save some lives," said Dr. Boris Pasche, lead author of the study. "We will be able to identify a larger number of individuals that are at risk of colorectal cancer and, in the long term, maybe decrease the cases of colorectal cancer and of people dying from it … "
The study that included Dr. Albert de la Chapelle, an Ohio State University professor of human cancer genetics, appears in the advanced on-line edition of the journal Science.
Protein found to control blood cell growth
PHILADELPHIA, Aug. 14 (UPI) -- U.S. medical scientists say they have discovered a specific protein signals stem cells in the bone marrow of mice to reproduce and remain at rest.
Assistant Professor of Pediatrics Wei Tong and her team of researchers at The Children's Hospital of Philadelphia studied hematopoeietic stem cells, or HSCs, in mice. HSCs can either reproduce or transform themselves into red blood cells, platelet cells or immune cells. Tong and her colleagues discovered a protein called Lnk signals HSCs to reproduce, rather than develop into other types of blood cells.
The research team said it also found most of the new stem cells were in a resting stage in the cell cycle. Resting cells are less likely to be rejected when they are used in bone marrow transplants.
Tong said her findings might help improve the success of bone marrow transplants and lead to better treatments for life-threatening blood diseases.
The study appears online in the Journal of Clinical Investigation.
