Scientists to map Chile earthquake site to capture fresh data

March 20, 2010 By Leave a Comment

Washington, March 20 (ANI): A team of scientists are all set to undertake an expedition to explore the rupture site of the 8.8-magnitude Chilean earthquake, which is one of largest quakes in recorded history.

The scientists are funded by the National Science Foundation (NSF) and affiliated with the Scripps Institution of Oceanography (SIO) at the University of California at San Diego.

The scientists hope to capitalize on a unique scientific opportunity to capture fresh data from the event.

They will study changes in the seafloor that resulted from movements along faults and submarine landslides.

The “rapid response” expedition, called the Survey of Earthquake And Rupture Offshore Chile, will take place aboard the research vessel Melville.

The Melville was conducting research off Chile when the earthquake struck.

“This rapid response cruise is a rare opportunity to better understand the processes that affect the generation and size of tsunamis,” said Julie Morris, NSF division director for Ocean Sciences.

“Seafloor evidence of the quake will contribute to understanding similar earthquake regions worldwide,” she added.

An important aspect of the rapid response mission involves swath multibeam sonar mapping of the seafloor to produce detailed topographic maps.

“Data from mapping the earthquake rupture zone will be made public soon after the research cruise ends,” Morris said.

The new data will be compared with pre-quake data taken by scientists at Germany”s Leibniz Institute of Marine Sciences (IFM-GEOMAR).

Several years ago, IFM-GEOMAR researchers conducted a detailed multibeam mapping survey off Chile.

Their data will be valuable for comparisons with the new survey to expose changes from the earthquake rupture, according to researchers.

“We’d like to know if the genesis of the resulting tsunami was caused by direct uplift of the seabed along a fault, or by slumping from shaking of sediment-covered slopes,” said Dave Chadwell, an SIO geophysicist and chief scientist of the expedition.

“We will look for disturbances in the seafloor, including changes in reflectivity and possibly shape, by comparing previous data with the new (rapid response) data,” he added.

Accoridng to Bruce Appelgate, associate director for Ship Operations and Marine Technical Support at SIO, “The earthquake was a tragedy for the people of Chile, but we hope this opportunity enables important new discoveries that can help us plan for future events.” (ANI)

Filed Under: International News Tagged With: , , , , , , , , , , , , , , , , , , ,

Cell division in bacteria just like clockwork

March 19, 2010 By Leave a Comment

Washington, March 19 (ANI): A new American study has found that cell division in cyanobacteria is controlled by same kind of circadian rhythms that govern human sleep.

The research conducted by scientists at MIT and the University of California at San Diego has appeared in the March 18 online edition of Science.

Previous research has demonstrated that although cyanobacteria do not “sleep” in the same way as humans, they cycle through active and resting periods on a 24-hour schedule. Cyanobacteria depend on sunlight for photosynthesis, so they are most active during the day.

The researchers showed, for the first time, how the circadian clock regulates the bacteria”s rate of cell division – their method of reproduction – in single cells.

Lead author Bernardo Pando, an MIT graduate student in physics, said: “These cells have to keep dividing, and the circadian oscillator regulates when they divide.”

In multicellular animals, including humans, cell division is crucial for renewal and repair, while out-of-control cell division causes cancer, so “understanding how cells are dividing is really of fundamental importance,” says Susan Golden, professor of molecular biology at the University of California at San Diego and an author of the paper.

Cyanobacteria maintain their circadian rhythms even when isolated from the naturally occurring daily light-dark cycles of the sun, just like humans. The scientists discovered that under conditions of moderate constant light, the cyanobacteria undergo cell division about once per day, and the divisions take place mostly at the midpoint of the 24-hour cycle.

To find how the cell division cycle is coupled to the circadian clock, the researchers sped up the cell cycle by boosting the intensity of light, enabling the cells to photosynthesize more, which increases the amount of energy available to them. The cells did start to divide more frequently, but in a pattern still linked to the circadian clock — they divided once a quarter of the way into the cycle, and again three-quarters into the cycle.

The research group also showed that the cyanobacteria enter a resting phase about 19 hours into the circadian cycle, after which they will not divide until the next cycle begins.

For the study, the researchers tracked single cells over a weeklong period. Proteins that govern the circadian clock were tagged with yellow fluorescent protein, so each cell”s position in the 24-hour cycle could be pinpointed. Photographs of the cells were taken every 40 minutes, so researchers could see when they divided.

This is the first time researchers have studied how cell cycle and circadian rhythms are coupled in individual bacterial cells.

Alexander van Oudenaarden, MIT professor of biophysics and senior author of the paper, said: “You can only do this by looking at single cells.”
(ANI)

Filed Under: International News Tagged With: , , , , , , , , , , , , , , , , , , ,

Now, software to analyse MR images and identify early Alzheimer’s disease

May 22, 2009 By Leave a Comment

Washington, May 22 (ANI): Scientists at Massachusetts General Hospital (MGH) claim that they have developed a piece of software that can prove helpful in analysing MRI studies of the brain and allow diagnosis of Alzheimer’s disease and of mild cognitive impairment, a lesser form of dementia that precedes the development of Alzheimer’s by several years.

Writing about their work in the journal Brain, the researchers have revealed that their software program can accurately differentiate patients with mild cognitive impairment or Alzheimer’s disease from normal elderly individuals based on anatomic differences in brain structures known to be affected by the disease.

“Traditionally Alzheimer’s has been diagnosed based on a combination of factors – such as a neurologic exam, detailed medical history and written tests of cognitive functioning – with neuroimaging used primarily to rule out other diseases such as stroke or a brain tumor,” says Dr. Rahul Desikan, of the Martinos Center and Boston University School of Medicine, lead author of the Brain paper.

“Our findings show the feasibility and importance of using automated, MRI-based neuroanatomic measures as a diagnostic marker for Alzheimer’s disease,” he added.

The researchers point out that mild cognitive impairment occurs in about 20 percent of elderly individuals, and that 80 percent of them develop Alzheimer’s within five or six years.

Given that medications to slow the progression of Alzheimer’s are in development, they say that the ability to treat patients in the earliest stages of the disease may significantly delay progression to dementia.

With a view to finding out whether MR imaging could produce diagnostic markers for mild cognitive impairment and Alzheimer’s disease, the researchers used FreeSurfer – an openly available imaging software package developed at the Martinos Center and the University of California at San Diego – to examine a number of neuroanatomic regions across a range of normal individuals and patients with mild cognitive impairment and Alzheimer’s disease.

In the first phase of the study, they analysed MR images of 97 elderly individuals, some who had been determined to have mild cognitive impairment and others who were cognitively normal.

The researchers said that the analysis of those images led to the identification of three brain regions where structural differences distinguished the normal controls from participants with mild cognitive impairment with an accuracy of 91 percent.

Earlier pathological and imaging studies have found evidence of early Alzheimer’s disease in these three areas – the hippocampus, entorhinal cortex and the supramarginal gyrus.

The research group then analyzed imaging data from 216 individuals in the Alzheimer’s Disease Neuroimaging Database to validate the accuracy and assess the reliability of the first-phase observations.

They revealed that 94 of the individuals were normal, 58 who had mild cognitive impairment at the time of imaging and went on to develop dementia, and 65 who had probable Alzheimer’s based on their clinical symptoms.

These participants also had a series of neuropsychological tests, and samples of cerebrospinal fluid were available for many of them.

Automated MRI measures of the same three areas identified in the first phase – entorhinal cortex, hippocampus, and supramarginal gyrus – discriminated individuals with mild cognitive impairment from normal elderly controls with 95 percent accuracy, and patients with Alzheimer’s were discriminated from normal controls with 100 percent accuracy.

The MRI measures also were significantly correlated with clinical and cognitive tests of dementia, particularly memory decline, and with biomarkers of cellular pathology such as the Alzheimer’s-associated forms of the tau and amyloid proteins.

“Our results indicate that these automated MRI measures are one effective way of identifying individuals in the earliest stages of Alzheimer’s disease, but before this technology can be used clinically, several follow-up studies need to be done,” says Desikan. (ANI)

Filed Under: Health News Tagged With: , , , , , , , , , , , , , , , , , , , , ,

Scientists move closer to “holy grail” of climate change science

May 18, 2009 By Leave a Comment

Washington, May 18 (ANI): A team of atmospheric chemists has moved closer to the first-ever direct detections of biological particles within ice clouds, which is considered the “holy grail” of climate change science.

The team, led by Kimberly Prather and Kerri Pratt of the University of California at San Diego, Scripps Institution of Oceanography, sampled water droplet and ice crystal residues at high speeds while flying through clouds in the skies over Wyoming, US.

Analysis of the ice crystals revealed that the particles that started their growth were made up almost entirely of either dust or biological material such as bacteria, fungal spores and plant material.

This study is the first to yield direct data on how airborne microorganisms work to influence cloud formation.

“If we understand the sources of the particles that nucleate clouds, and their relative abundance, we can determine their impact on climate,” said Pratt, lead author of the research paper.

The effects of tiny airborne particles called aerosols on cloud formation have been some of the most difficult aspects of weather and climate for scientists to understand.

In climate change science, which derives many of its projections from computer simulations of climate phenomena, the interactions between aerosols and clouds represent what scientists consider the greatest uncertainty in modeling predictions for the future.

“By sampling clouds in real time from an aircraft, these investigators were able to get information about ice particles in clouds at an unprecedented level of detail,” said Anne-Marie Schmoltner of NSF’s (National Science Foundation’s) Division of Atmospheric Sciences, which funded the research.

“By determining the chemical composition of the very cores of individual ice particles, they discovered that both mineral dust and, surprisingly, biological particles play a major role in the formation of clouds,” she added.

The Ice in Clouds Experiment – Layer Clouds (ICE-L) team mounted a mass spectrometer onto a C-130 aircraft operated by the National Center for Atmospheric Research (NCAR) in Boulder, Colorado, and made a series of flights through a type of cloud known as a wave cloud.

The researchers performed in-situ measurements of cloud ice crystal residues and found that half were mineral dust and about a third were made up of inorganic ions mixed with nitrogen, phosphorus and carbon, the signature elements of biological matter.

The team demonstrated that both dust and biological material indeed form the nuclei of these ice particles, something that previously could only be simulated in laboratory experiments.

“This has really been kind of a holy grail measurement for us,” said Prather. (ANI)

Filed Under: Science News Tagged With: , , , , , , , , , , , , , , , , , , , ,