Change of Carbon Metabolic Activity of Rhizobium Under Carbon Starvation

One fast growing strain of Rhizobium sp (Vigna mungo) VBS 1 was tested for its metabolic activities under carbon starvation. Specific activities of the catabolic enzymes like phosphofructokinase, fructose-1,6-bisphosphate aldolase, iso-citrate dehydrogenase and malate dehydrogenase decreased remarkably whereas, induction of two anapleurotic enzymes like fructose-1,6-bisphosphatase and iso-citrate lyase took place in the cell-free extract of the strain. Almost unchanged specific activity of the enzyme glyceraldehyde-3-phosphate dehydrogenase indicated its key role in maintaining a balance between catabolic and anabolic activities under carbon starvation.     

Carbon monoxide poisoning

Carbon monoxide poisoning is a significant cause of illness and death. Its protean symptoms probably lead to a gross underestimation of its true incidence. Low levels of carbon monoxide aggravate chronic cardiopulmonary problems, and high levels are associated with cardiac arrhythmias and cerebral edema. Patients who survive acute poisoning are at risk of delayed neurologic sequelae. The measurement of carboxyhemoglobin levels does not reveal the tissue levels of carbon monoxide but is useful in determining therapy. Treatment includes the monitoring and management of cardiac arrhythmias and oxygenation. Hyperbaric oxygenation is beneficial, but there are currently no definite criteria for its use.     

Carbon Nanofiber Production

Holistic understanding of nanotechnology using systems analysis tools is essential for evaluating claims about the potential benefits of this emerging technology. This article presents one of the first assessments of the life cycle energy requirements and environmental impact of carbon nanofibers (CNFs) synthesis. Life cycle inventory data are compiled with data reported in the open literature. The results of the study indicate relatively higher life cycle energy requirements and higher environmental impact of CNFs as compared to traditional materials, like primary aluminum, steel, and polypropylene, on an equal mass basis. Life cycle energy requirements for CNFs from a range of feedstock materials are found to be 13 to 50 times that of primary aluminum on an equal mass basis. Similar trends are observed from the results of process life cycle assessment (LCA), as conveyed by different midpoint and endpoint damage indicators. Savings in life cycle energy consumption and, hence, reductions in environmental burden are envisaged if higher process yields of these fibers can be achieved in continuous operations. Since the comparison of CNFs is performed on an equal mass basis with traditional materials, these results cannot be generalized for CNF‐based nanoproducts. Quantity of use of these engineered nanomaterials and resulting benefits will decide their energy and environmental impact. Nevertheless, the life cycle inventory and the results of the study can be used for evaluating the environmental performance of specific CNF‐based nanoproducts.