Towards the end of the 1940s the air’s contamination began in Mexico. It just happened when Mexico starts its industrial growing. During these years the population increased notably. Industrial growing in the 1950s was carried through an urbanization process (Restrepo, 1992). Mexico City was the first because it had industries, services, government offices, culture attractions and higher educat...

Since the Euro-III standard was adopted, the main methods to inhibit NOx production in diesel engines are exhaust gas recirculation (EGR) and select catalyst reduction (SCR). On these methods SCR offers great fuel economy, so it has received wide attention. However, there also exists a trade-off law between NOx conversion efficiency and NH3 slip under dynamic conditions. To inhibit NH3 slip wit...

Nitrogen oxides (NOx) are besides particulate matter (PM), especially for diesel engines, the most relevant emission components. Against this background and the fact that passenger car emission legislation is permanently becoming stricter, there is still a growing interest in minimizing these pollutants. Beside the highly nonlinear behavior of engines also the tradeoff between PM and NOx is a c...

Nitrogen oxides (NOx) and black carbon (BC) emission factors (EF) of 440 on-road diesel trucks were determined by conducting on-road chasing studies in Beijing and Chongqing, China, in the winter 2010. NOx and BC EF distributions are reported. The median NOx EFs for trucks sampled on level roads in Chongqing and Beijing are 40.0 and 47.4 g kg-fuel 1, respectively. The median BC EFs are 1.1 and ...

We tested the effects of insulin on production of nitrous oxide (NO)-related substances (nitrites and nitrates [NOx]) after (15)N-arginine intravenous infusion and on asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) concentrations in conditions reportedly associated with altered NO availability, i.e., aging, hypertension, hypercholesterolemia, and type 2 diabetes mellitu...

If adopted by EPA, proposed new regulations on stack emissions will force many utilities with coalfired boilers to reduce their NOx emissions to levels which are substantially lower then can be achieved with current low NOx burner technology. To meet these requirements, some utilities are anticipating the need to use selective catalytic reduction (SCR) for NOx control. New SCR catalysts under d...

Vehicle NOx emission regulations are becoming more and more stringent worldwide. A selective catalytic reduction (SCR) system which uses ammonia as the reductant to reduce tailpipe NOx emissions is widely adopted by Diesel engine applications. For SCR control, a NOx sensor is commonly used to monitor the emissions, however it has been discovered that NOx sensors typically are cross-sensitive to...

High blood pressure has been shown to elicit impaired dilation in the vasculature. The purpose of this investigation was to elucidate the mechanisms through which high pressure may elicit vascular dysfunction and determine the mechanisms through which regular aerobic exercise protects arteries against high pressure. Male C57BL/6J mice were subjected to 2 wk of voluntary running (~6 km/day) for ...

NADPH oxidases (Nox) represent a family of hetero-oligomeric enzymes whose exclusive biological function is the generation of reactive oxygen species (ROS). Nox-derived ROS are essential modulators of signal transduction pathways that control key physiological activities such as cell growth, proliferation, migration, differentiation, and apoptosis, immune responses, and biochemical pathways. En...

Nitric oxide (NO) may play important roles in rheumatoid arthritis (RA). RA is an inflammatory disease involving joints and other systems including salivary glands. To assess NO production in RA patients, we compared levels of serum, urine, and salivary nitrite and nitrate (NOx) in patients with RA and normal subjects, and we examined the relationships of these measures to disease activity. Ser...