Effect of a nitric oxide synthase inhibitor and a glucocorticosteroid on exhaled nitric oxide

Nitric oxide (NO) is produced by a variety of cells within the respiratory tract, including inflammatory epithelial cells. NO has been detected in the exhaled air of normal human subjects, and its concentration is raised in asthmatic patients. To study whether exhaled NO arises from the respiratory tract, we administered a NO synthase (NOS) inhibitor, NG-monomethyl-L-arginine (L-NMMA), by inhalation (490 mg) in a double-blind randomized manner in nine normal and six asthmatic subjects. Because exhaled NO may arise from an inducible isoform of NO synthase that may be inhibited by glucocorticosteroids, we also studied the effects of oral prednisolone (30 mg orally for 3 d) in seven normal and six asthmatic subjects in a separate double-blind crossover study with matched placebo. After nebulized L-NMMA, there was a significant fall in peak exhaled NO compared with saline control values, with a mean fall of 43.6 +/- 5.6% in normal subjects (p < 0.01) and of 39.7 +/- 6.5% (p < 0.01) in asthmatic subjects, which persisted for 4 h. There were no effects of L-NMMA inhalation on heart rate, blood pressure, or FEV1 in either normal or asthmatic patients. Administration of oral prednisolone (30 mg) resulted in a fall in exhaled NO concentrations in asthmatic subjects by 21.6 +/- 5.0% at 48 h (p < 0.01) but no significant change in normal subjects. These data suggest that NOS inhibitors may be safely given in normal and asthmatic patients and that the increased exhaled NO seen in asthmatic patients is likely to be caused by induction of inducible NOS.     

Size effects in the assessment of discipline-contribution scores: An example from the social sciences

Pichappan's formulation of the Discipline-Contribution Score (DCS) in the identification of core disciplinary journals is applied to social science literature. Modifications are made to Pichappan's method to cater for problems associated with low citation counts. Further analysis is undertaken to verify Pichappan's claims concerning the size-independent nature of the DCS score. The proposed modified formulation of the DCS calculation facilitates research into small research fields, and those characterised by low citation rates. The modified equation is tested on business and management literature.     

Localized contact formation by erythrocyte membranes: electrostatic effects

The topology of the contact seam of human erythrocytes adhered by dextran, an uncharged polymer, has been examined. Particular attention has been paid to the influence of electrostatic intermembrane interactions since their magnitude and range can be accurately estimated. Normal cells formed a continuous seam, whereas erythrocytes with pronase-modified glycocalices formed localized contact points on adhesion in 72 kDa dextran in buffered 145 mM NaCl. The dependence of the inter-contact distance lambda on dextran concentration [D] over the range 2-6% w/v, was given by lambda = C[D]-0.62, where C was a constant. The index of [D] was independent of dextran molecular mass over the range 20 to 450 kDa. The inter-contact distance for pronase-pretreated cells in 6% w/v 72 kDa dextran increased from 0.78 to 1.4 microns as [NaCl] was reduced through the range 145 to 90 mM and the suspending phase was maintained at isotonicity by using sorbitol to replace NaCl. The formation and lateral separation of the contact points are discussed from the perspective of linear interfacial instability theory. The theory allows a quantitative explanation for the experimentally observed dependence of inter-contact distance and of disturbance growth rate on change in electrostatic interaction. The results suggest that the dominant wavelength, determining the inter-contact distance, is established on approaching membranes when the layers of cell surface charge are separated by a perpendicular distance of < 14 nm (bilayer separation of 24 nm).     

Cognitive networks: adaptation and learning to achieve end-to-end performance objectives

In this article we advance the idea of a cognitive network, capable of perceiving current network conditions and then planning, learning, and acting according to end-to-end goals. Cognitive networks are motivated by the complexity, heterogeneity, and reliability requirements of tomorrow's networks, which are increasingly expected to self-organize to meet user and application objectives. We compare and contrast cognitive networks with related research on cognitive radios and cross-layer design. By defining cognitive networks, examining their relationship to other technologies, discussing critical design issues, and providing a framework for implementation, we aim to establish a foundation for further research and discussion     

光存储媒体注塑工艺最优化:品质改善和成本节约

媒体产业发展到今天，各大厂商所面临的问题都是如何保证企业高产能、低成本的进行生产，维持一个高的和长期的品质标准。目前DVD生产循环时间已经达到3秒钟之内，如何保证最优化的生产工艺成为保障产品符合标准的首要条件。     

Effects of the SMART Classroom Curriculum to Reduce Child and Family Screen Time

Evidence for adverse effects of screen media exposure has led to recommendations to limit children's screen time. This paper describes a randomized controlled trial of SMART (Student Media Awareness to Reduce Television), an 18-lesson, theory-based classroom curriculum to reduce screen time among third and fourth grade children in two matched public elementary schools ( n = 181). Intervention school children significantly reduced their weekday television viewing and weekday and Saturday video game playing compared to controls. Greater effects were found among boys and more adult-supervised children. Mothers, fathers, and siblings and other children in intervention school households also reduced their television viewing. The findings demonstrate the efficacy of a classroom intervention to reduce screen time among elementary school children and their family/household members.