AFR

Ascorbate (vitamin C) is a vital antioxidant molecule in the brain. However, it also has a number of other important functions, participating as a co-factor in several enzyme reactions including catecholamine synthesis, collagen production and regulation of HIF-1α. Ascorbate is transported into the brain and neurons via the Sodium-dependent Vitamin C Transporter-2 (SVCT2), which causes accumulation of ascorbate within cells against a concentration gradient. Dehydroascorbic acid, the oxidized form of ascorbate, is transported via glucose transporters of the GLUT family. Once in cells, it is rapidly reduced to ascorbate. The highest concentrations of ascorbate in the body are found in the brain and neuroendocrine tissues such as adrenal, although the brain is the most difficult organ to deplete of ascorbate. Combined with regional asymmetry in ascorbate distribution within different brain areas, these facts suggest an important role for ascorbate in the brain. Ascorbate is proposed as a neuromodulator of glutamatergic, dopaminergic, cholinergic and GABAergic transmission and related behaviors. Neurodegenerative diseases typically involve high levels of oxidative stress and thus ascorbate has been posited to have potential therapeutic roles against ischemic stroke, Alzheimer's disease, Parkinson's disease and Huntingdon's disease.

Laser-induced fluorescence has been mainly used to characterise the two-dimensional fuel vapour concentration inside the cylinder of a multi-valve twin-spark ignition engine equipped with high-pressure multi-hole injectors. The effects of injection timing, in-cylinder charge motion and injector tip layout have been quantified. The flexibility in nozzle design of the multi-hole injectors has proven to be a powerful tool in terms of matching overall spray cone angle and number of holes to specific engine configurations. Injection timing was found to control spray
impingement on the piston and cylinder wall, thus contributing to quick and efficient fuel evaporation. It was confirmed that in-cylinder charge motion plays a major role in engine’s stable
operation by assisting in the transportation of the air-fuel mixture towards the ignition locations (i.e. spark-plugs) in the way of a uniformly distributed charge or by preserving stratification of the
charge depending on operating mode of the engine

OBJECTIVE: To identify the prevalence of factors associated with insufficient physical activity levels and sedentary behavior among adolescents. METHODS: In this cross-sectional study 4,210 students (14-19 years old) attending public high-schools were selected using random two-stage cluster sampling. Data were collected by using the Global School-based Student Health Survey. Subjects who reported performing 60 minutes or more of moderate to vigorous physical activity five days a week or more were classified as physically active, while the remainder was classified as insufficiently active. Subjects who reported watching TV three or more hours a day were considered to be exposed to sedentary behavior. Analyses were carried out by using Chi-square tests and binary logistic regression. RESULTS: The prevalence of insufficiently active subjects was 65.1% (CI95% 63.7-66.6). Gender, place of residence (rural/urban), time of day attending school, occupational status, and enrollment in physical education were identified as factors significantly associated with exposure to insufficient levels of physical activity. Prevalence of exposure to sedentary behavior was 40.9% (CI95% 39.4-42.4) on week days and 49.9% (CI95% 48.4-51.4) on weekend days. Place of residence, time of day attending school, occupational status and enrollment in physical education were identified as factors significantly associated with exposure to sedentary behavior on week days, whereas on weekend days exposure to sedentary behavior was related to gender, age and time of day attending school. CONCLUSION: This study showed a high prevalence of insufficient physical activity levels and exposure to sedentary behaviors among adolescents.

Abstract: Laser-induced fluorescence has been mainly used to characterise the two-dimensional fuel vapour concentration inside the cylinder of a multi-valve twin-spark ignition engine equipped with high-pressure multi-hole injectors. The effects of injection timing, in-cylinder charge motion and injector tip layout have been quantified. The flexibility in nozzle design of the multi-hole injectors has proven to be a powerful tool in terms of matching overall spray cone angle and number of holes to specific engine configurations. Injection ...