Stories tagged Proceedings of the National Academy of Sciences

Jul
22
2008

Eutrophication: Agricultural run-off rich in fertilizers stimulates rampant growth of algae.
Eutrophication: Agricultural run-off rich in fertilizers stimulates rampant growth of algae.Courtesy NASA

Human populations effect lakes

Human sewage and fertilizer runoff effects the health of lakes. It often causes huge algal blooms, kills fish, and creates other problems.

Long term study of "cultural eutrophication" released

For 37 years researchers have examined the best ways to control this "cultural eutrophication" process of lakes by varying the levels of phosphorous and nitrogen added to the lake.

After completing one of the longest running experiments ever done on a lake, researchers from the University of Alberta, University of Minnesota and the Freshwater Institute, contend that nitrogen control, in which the European Union and many other jurisdictions around the world are investing millions of dollars, is not effective and in fact, may actually increase the problem of cultural eutrophication.

Time to rethink current practices for healthy lakes

"David Schindler, professor of ecology at the University of Alberta, and one of the leading water researchers in the world, wants to change current practice in controlling nitrogen runoff by stating that

"Controlling nitrogen does not correct the polluted lakes, and in fact, may actually aggravate the problem and make it worse."

This study done by the University of Alberta, University of Minnesota and the Freshwater Institute appears in the journal, Proceedings of the National Academy of Sciences.

Source: PhysOrg.com

Jun
08
2008

Are nanomaterials safe?

Nanomaterials & health
Nanomaterials & healthCourtesy GiselaGiardino²³
Nanomaterials show promise for curing diseases. But, how can we assess the risk of these nanomaterials causing problems within the human organism. Studies in animals are expensive and time consuming. Also, different cell types can respond differently to the same nanomaterial.

A fast screening method could help separate the good from the bad

Stanley Shaw and researchers from the Broad Institute of Harvard and MIT recently tested 50 different nanoparticles--mainly particles used for medical imaging, including mostly iron-based particles, as well as several types of quantum dots. The particles also had various chemical coatings.

The researchers tested each of the nanoparticles in four different types of cells--immune cells from mice, two types of human blood-vessel cells, and human liver cells--and at four different dosages. To create the different combinations, a robotic system similar to that used for drug screening placed the nanoparticles inside tiny wells on a plate containing hundreds of separate wells. Each well contained one cell type. The screening system then detected changes in the cells' metabolism in response to the nanomaterial. Computer software analyzed the data, looking for relationships between the different particles. Technology Review

The new screening tool, described in the Proceedings of the National Academy of Sciences, could help narrow the list of nanomaterials that need to undergo animal testing.