background: nitrogen oxides occur in the atmosphere in six forms of namely: n2o , no , no2 , n2o3, n2o4 and n2o5 .among these oxides no2 is the most important air pollutant because of its relatively high toxicity and its ubiquity in ambient air. in this research griess-saltzman method was utilized for determination of nitric oxide and nitrogen dioxide in the atmosphere of different laboratories...

The process of nitrogen fIXation by the legumes imposes carbon (C) energy burden on the plant. The photosynthate translocated from the leaves provides carbon skeleton, reducing power and energy required for the symbiotic nitrogen fIXation. Sucrose from the shoot is converted to organic acids, principally dicarboxylates that are supplied to bacteroids to provide reductant for the support of key ...

Conical intersections play a crucial role in the chemistry of most polyatomic molecules, ranging from the simplest bimolecular reactions to the photostability of DNA. The real-time study of the associated electronic dynamics poses a major challenge to the latest techniques of ultrafast measurement. We show that high-harmonic spectroscopy reveals oscillations in the electronic character that occ...

OBJECTIVES To investigate the relation between fluctuations in personal exposure to nitrogen dioxide (NO(2)) in school children and changes in outdoor NO(2) concentrations. METHODS 114 Asthmatic school children aged 7-12 years were recruited from the Southampton area. Weekly average personal exposures to NO(2) were measured over a 13 month period with passive diffusion tubes. At the same time...

Exposure to urban air pollution, ultrafine particles or gases, is associated with acute cardiovascular mortality and morbidity. We investigated the effect of ambient air pollution on endothelial function in 40 healthy white male nonsmokers spontaneously breathing ambient air in Paris, France. Air pollutant levels (nitrogen, sulfur and carbon oxides, and particulate matter) were averaged during ...

Few studies have investigated associations between nonoccupational exposure to ambient volatile organic compounds and lung cancer. We conducted a case-control study of 445 incident lung cancers and 948 controls (523 hospital, 425 general population) in Toronto, Ontario, Canada, between 1997 and 2002. Participants provided information on several risk factors, including tobacco use, secondhand ex...

With neurodevelopmental outcome of very low birthweight (VLBW) infants being adversely affected by inadequate nutrition during the first few weeks of life, there is an urgent need for more specific nutritional data on the sick VLBW ventilator dependent infant. The development of a new mass spectrometry gas analysis indirect calorimetry system which is non-invasive and can operate over several h...

Investigators examined 5,654 children enrolled in the El Paso, Texas, public school district by questionnaire in 2001. Exposure measurements were first collected in the late fall of 1999. School-level and residence-level exposures to traffic-related air pollutants were estimated using a land use regression model. For 1,529 children with spirometry, overall geographic information system (GIS)-mo...