University of Iowa researchers and their colleagues have found a way to improve existing estimates of the amount of carbon absorbed by plants from the air, thereby improving the accuracy of global warming and land cover change estimates, according to a paper published in the Nov. 13 issue of the journal Science.

By knowing the effects of plants on the atmosphere, scientists will be better able to determine the amount of human-generated carbon dioxide (CO2) injected into the atmosphere, according to Greg Carmichael, professor of chemical and biochemical engineering in the UI College of Engineering and co-director of the Center for Global and Regional Environmental Research (CGRER).

“This work demonstrates a technique to get a direct estimate of the photosynthetic uptake by plants over large regions,” he said. “This is critical because in the carbon budget analysis we need to be able to quantify the various sources of carbon dioxide, especially the carbon dioxide from anthropogenic activities and the uptake of carbon dioxide by plants.

“Both are needed if we are to come up with better management strategies in reducing manmade emissions and in the case of plants increasing their carbon uptake,” said Carmichael, who was named in September to a National Academy of Sciences (NAS) study on the significance of the international transport of air pollutants.

In addition to Carmichael, the paper’s UI co-authors include lead author Elliott Campbell, who participated in the study while earning his doctoral degree at Iowa and who currently is assistant professor of engineering at the University of California, Merced; Tianfeng Chai, former postdoctoral student at CGRER and currently at the U.S. EPA Air Resources Lab, Research Triangle Park, N.C.; Marcelo Mena-Carrasco, former UI doctoral candidate and currently at the Department of Environmental Engineering, Universidad Andres Bello, Santiago, Chile, and the Molina Center for Energy and the Environment, MIT; Youhua Tang, formerly of CGRER and now at the National Oceanic and Atmospheric Administration/Scientific Applications International Corporation (NOAA/SAIC); Jerald Schnoor, professor of civil and environmental engineering and CGRER co-director; and Charles Stanier, assistant professor of chemical and biochemical engineering, and assistant research engineer at IIHR-Hydroscience and Engineering.

In the paper, Campbell and his colleagues show that measurements of carbonyl sulfide (COS), a naturally occurring atmospheric gas consumed by plants, can be related to plant uptake of carbon dioxide. The hope is that future work can exploit this relationship to reduce uncertainty in carbon dioxide fluxes. The paper tells how COS analysis may be used as a measurement-based photosynthesis tracer.

“We’ve always looked at the total change in CO2, but now we can look for the influence of photosynthesis on this total change,” remarked Campbell. “Our approach, based on the relation of carbonyl sulfide to photosynthesis, gives us this unique ability.”

The researchers used a NASA aircraft and NASA/NOAA funding to gather and analyze airborne observations of COS and carbon dioxide concentrations during the growing season over North America with a 3-D atmospheric transport model. They note that the study likely will result in additional measurements of COS being added to current carbon networks.

They plan to continue their work and use data from the NOAA-supported Iowa Tall Tower atmospheric measurement site in West Branch, Iowa, some 10 miles from the UI campus.

Source : Eurekalert ! via University of Iowa

In a study using rats as as animal model, five weeks exposure to cigarette smoke was associated with the activation of enzymes called mitogen-activated protein kinases that govern cell growth and survival in heart muscle. Activation of these enzymes may be a key event in cigarette smoke-induced heart injury, says Mariann Piano, professor of biobehavioral health science in the UIC College of Nursing and lead researcher of the study.

Heart disease probably develops as a result of complex interactions among many elements in cigarette smoke, she said.

“Cigarette smoke contains more than 4,000 different chemicals, one of which is nicotine,” Piano said. “However, the effect of nicotine on the initiation and progression of cigarette smoke-mediated cardiovascular events remains controversial.”

To date, small clinical trials of nicotine replacement therapies have not shown increased cardiovascular risk, even in patients with cardiovascular disease, Piano said. This suggested the need to study cigarette smoke as a whole.

In the new study, published in the November issue of the European Journal of Heart Failure, rats were exposed either to cigarette smoke or to normal room air. After five weeks, the animals were examined by echocardiography. Heart tissue was examined under the microscope and by Western blot analysis, used to detect specific proteins in tissue samples.

The results showed exposure to cigarette smoke was associated with significant changes in the shape of the left ventricle, the heart’s main pumping chamber, and an increase in the levels of the activated forms of the enzymes in the heart muscle. Researchers also found increased levels of norepinephrine, a hormone released when a stressful event causes any of a host of physiological changes, in urine samples taken from the animals.

Piano said this is the first study to demonstrate that cigarette smoke-induced ventricular remodeling is linked to the activation of mitogen-activated protein kinases. She received the American Heart Association’s 2008 Katharine A. Lembright Award for excellence in cardiovascular research at the association’s annual meeting in New Orleans on Nov. 9.

Source : Eurelalert ! via University of Illinois at Chicago