Mystery of Solar System’s earliest rocks explained
Cosmochemists at UC San Diego have solved a mystery about the formation of the solar system: Why stony meteorites – among the oldest objects in the solar system – contain vastly different oxygen isotopes from those of terrestrial rocks from Earth, the Moon, and Mars.
Oxygen isotopes usually sort out according to mass. For example, oxygen-17, with just one extra neutron, is incorporated into molecules half as often as oxygen-18, with two extra neutrons. In stony meteorites recovered on Earth, the two heavier oxygen isotopes show up in equal proportions. Among ideas put forth to explain the anomaly is a physical chemical principle called “symmetry.”
To test this idea, researchers recreated conditions of the early solar system by filling a hockey puck-sized chamber with pure oxygen, varying amounts of pure hydrogen, and a tiny nugget of solid silicon monoxide. These are ingredients found in interstellar clouds, the starting point for our solar system.
Using a laser to vaporize the silicon monoxide, the gas reacted with the oxygen and hydrogen to form silicon dioxide, a solid that settled out as dust. When analyzed, the dust revealed a mix of oxygen isotopes that matched the anomalous pattern found in stony meteorites.
—Findings appear in the journal Science. News release at http://bit.ly/16zAwKR
High quality transcriptome from as few as 50 cells
UC San Diego bioengineers have created a new method for analyzing RNA transcripts from samples as small as 50 to 100 cells. Heretofore, standard methods required samples of thousands of cells. RNA transcripts serve as a proxy for which genes are being expressed and at what levels.
The new approach – called Designed Primer-based RNA sequencing (DP-seq) – could be used to develop inexpensive and rapid methods for diagnosing cancers at early stages, as well as better tools for forensics, drug discovery, and developmental biology.
The announcement of the DP-seq protocols has sparked tremendous interest from the scientific community, with the technique already being applied to a wide range of biological and medical research questions from brain cancer, to liver function, and stem-cell biology.
—Findings appear in the journal Nature Scientific Reports. News release at http://bit.ly/1bhkpTJ
Generic drug treats alcohol dependence
The generic drug gabapentin – prescribed for epilepsy and pain relief – appears to be safe and effective in the treatment of alcohol dependence.
In a clinical trial conducted by scientists at The Scripps Research Institute (TSRI), 150 recently abstinent people with alcohol dependence were randomly assigned varying doses of gabapentin or else received a placebo. Over 12 weeks of treatment, the high-dose group refrained from heavy drinking twice as often as the placebo group (45 percent vs. 23 percent) and entirely abstained four times as often (17 percent vs. 4 percent). The drug also reduced the number of drinks consumed, as well as patient reports of cravings, depression, and sleeplessness associated with alcohol dependence.
Gabapentin appears to work by normalizing levels of a neurotransmitter in an emotion-mediating part of the brain, thereby reducing anxiety and other stress-related withdrawal symptoms.
About 8.5 million Americans are thought to be alcohol dependent, yet less than 10 percent are prescribed FDA-approved medications for the condition, due in part to limitations of existing drugs. TSRI scientists believe gabapentin has the potential to fill this treatment gap.
—Findings appear in the journal JAMA Internal Medicine. News release at http://bit.ly/HrU5yC
Lynne Friedmann is a science writer based in Solana Beach.
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