Graphene functionalization is achieved
EVANSTON, Ill., May 19 (UPI) -- U.S. scientists say they have developed a chemical functionalization technology that will allow graphene to be used in a wide range of technologies.
Graphene is an atomically thin sheet of carbon that has potential use in high-performance electronics. And while the physics of graphene is well understood, chemical functionalization of graphene has proved elusive.
Functionalization is a process that binds molecules to the carbon atoms of a nanotube to allow the blending of nanotubes into materials such as composites.
Now Northwestern University researchers say they've identified conditions for chemically functionalizing graphene with the organic semiconductor perylene-3,4,9,10-tetracarboxylic-dianhydride, also know as PTCDA.
The scientists said PTCDA self-assembles into a molecularly pristine monolayer that's nearly defect-free. In addition, the PTCDA monolayers are stable at room temperature and atmospheric pressure, suggesting their use as a seeding layer for subsequent materials deposition.
"Graphene has captured the imagination of researchers worldwide due to its superlative and exotic electronic properties," Professor Mark Hersam said. "However, harnessing these properties requires the development of chemical functionalization strategies that will allow graphene to be seamlessly integrated with other materials that are commonly found in real-world technology. The stability and uniformity of the chemistry demonstrated here suggest it can be used as a platform for many device applications."
The research team that included graduate student Qing Hua Wang reports the study in the journal Nature Chemistry.
Many diabetes drugs in development
RALEIGH, N.C., May 19 (UPI) -- A new report says there are a record number of diabetes medications being developed in the United States, either in clinical trials or awaiting approval.
The report, prepared by the Pharmaceutical Research and Manufacturers of America, reports U.S. pharmaceutical research and biotechnology companies are testing a record 183 new diabetes medicines.
The report was released Tuesday during a Raleigh, N.C., news conference
"We released this report in North Carolina because of the alarming rise in the number of new cases of diabetes in the state," PhRMA Senior Vice President Ken Johnson said. "Diabetes is a major health problem in North Carolina, where an estimated 600,000 people suffer from the disease."
He said, nationwide, diabetes affects more than 30 million people -- about 8 percent of the U.S. population -- with new cases increasing more than 90 percent among adults during the last 10 years.
Diabetes is a chronic disease in which the body does not produce or properly use insulin, a hormone needed to convert sugar, starches and other food into energy. The cause of diabetes has not been determined.
Study: Climate change affects polar bears
WASHINGTON, May 19 (UPI) -- A U.S. study refutes a publicized criticism of the negative effects of climate change on polar bears, supporting the listing of them as a threatened species.
The study -- conducted by scientists from the U.S. Geological Survey, the Woods Hole Oceanographic Institution, the Universities of Alaska and Maryland, the Canadian Wildlife Service and the U.S. Forest Service -- refutes point-by-point the criticism of negative polar bear population predictions. The new study is said to reinforce the U.S. Department of Interior's May 2008 decision to list polar bears as a threatened species.
"The decision to list the polar bear as threatened was politically charged, and the scientific research on which it was based attracted some criticisms," Woods Hole biologist Hal Caswell said. "Our new study shows that … (those criticisms were) based on misconceptions about climate models, the arctic environment, polar bear biology and statistical and mathematical methods."
The new research appeared in the April 22 online edition of the journal Interfaces and is to appear in that journal's July-August print edition.
Meningococcal bacteria mechanism is found
NOTTINGHAM, England, May 19 (UPI) -- British medical scientists say they have discovered how meningococcal bacteria break through the body's natural defense system to attack the brain.
University of Nottingham researchers said their discovery could lead to better treatment and vaccines.
The scientists said it can take just hours after symptoms appear for someone to die from bacterial meningitis, which in childhood is nearly exclusively caused by the respiratory tract pathogens Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenzae.
The mechanism used by those lethal bacteria to break through the blood brain barrier has been unknown.
But a team led by Professor Dlawer Ala'Aldeen discovered all three pathogens target the same receptor on human cerebrovascular endothelial cells -- the specialized filtering system that protects the brain from disease -- enabling the organisms to cross the blood-brain barrier.
That finding suggests disruption or modulation of the interaction of bacterial adhesins with the receptor might offer broad protection against bacterial meningitis and provide a therapeutic target for the prevention and treatment of the disease.
The research, conducted in collaboration with St. Jude Children's Research Hospital in the United States, appears in The Journal of Clinical Investigation.
