Tunable colors and conductivity by electroless growth of Cu/Cu2O particles on sol-gel modified cellulose

Nano Research - Development of colored surfaces by formation of nano-structured aggregates is a widely used strategy in nature to color lightweight structures (e.g. butterflies) without the use of...     

Metabolism of Zidovudine

1. The anti-HIV drug zidovudine (3'-azido-2',3'-dideoxythymidine; ZDV) has three important pathways of metabolism. ZDV is a prodrug and must be phosphorylated in lymphocytes in order to exert its antiviral action. However, in quantitative terms this is a minor pathway probably accounting for less than 1% of the overall metabolic profile. The predominant pathway of metabolism is glucuronidation to GZDV and the metabolite is renally excreted. A further metabolite, derived by reduction of the azido moiety is 3'-amino-3'-deoxythymidine (AMT). 2. Zidovudine glucuronidation has been characterised in human liver microsomes. A number of drugs (e.g., naproxen, indomethacin and probenecid) have been shown to inhibit the in vitro conjugation of ZDV. Some of these drugs have also been co-administered with ZDV in HIV-positive patients. Significant pharmacokinetic interactions have been demonstrated with probenecid, naproxen and fluconazole. 3. 3'-amino-3'-deoxythymidine formation is probably mediated by both cytochrome P450 isozymes and NADPH-cytochrome P450 reductase. Peak plasma concentrations of AMT are approximately 10-15% of ZDV in patients. This is a potentially important metabolite because of its alleged cytotoxicity. 4. Measurement of intracellular ZDV phosphates in patients provides the key to our understanding of both the efficacy and toxicity of ZDV. Important recent work has demonstrated that as patients deteriorate (i.e., CD4 counts decrease below 100 x 10(6)/L), there is a corresponding increase in intracellular ZDV-monophosphate. This could have toxicological implications.     

Correlation of the reactivity,the active surface area and the total surface area of thin films of pyrolytic carbon

Using thin films of pyrolytic carbon the rate of the reaction with oxygen has been measured over the temperature range 625–740°C and at pressures of oxygen from 6–100 torr. The active surface area (ASA) of the films was measured from the total concentration of strongly-bound complexes with oxygen on the surface and the relative total surface area (TSA) was measured by low-temperature adsorption of nitrogen. A maximum in reactivity and in ASA was observed for films of average thickness of about 20 nm with a TSA of about 30 m² g^?1. At the maximum the ASA and TSA were essentially equal. The results are interpreted in terms of the mechanism of formation of pyrolytic carbon in the initial stages.     

Adsorption behavior of heavy metal ions on cellulose graft copolymers

The adsorption behavior of cadmium, copper and lead ions on holocellulosic materials containing various levels of polyacrylonitrile and poly(acrylic acid) grafts was examined. The amount of metal ions adsorbed per gram of the modified cellulosic substrate depended on the metal ion type, the nature and level of the incorporated graft polymer. In all cases grafting increased the metal ion-binding capacity of the cellulosic materials (by up to 50% for Cu (II) ions). The influence of temperature and initial metal ions concentration on the sorption behavior of the metal ions on the composite materials was investigated.     

Finite element analysis of tailored sheet forming processes considering laser welding zone

The finite element formulation for predicting strain distributions and weld line movements in the forming processes of tailored sheet metals is developed. The material properties of the welding zone such as strength coefficient, work-hardening exponent, and plastic anisotropic parameter are analytically obtained from those of base metals based on the tensile tests. The welding zone is modelled with the several, narrow finite elements called by weld elements. To verify the finite element formulation for tailored blanks, the forming processes of autobody door inner panel section and hemispherical dome are simulated. FEM predictions are compared and showed good agreements with experimental measurements.     

Water quality prediction capabilities of WASP model for a tropical lake system

Water quality modelling facilitates our better understanding of the processes taking place in a lake system, and conservation plans to address them. The water quality analysis simulation programme (WASP) was used in this study to predict daily variations in water quality parameters, namely dissolved oxygen, nitrate, phosphate and chlorophyll‐a and biochemical oxygen demand concentrations in a tropical lake system. The lake was divided into eight segments with the respective morphological, environmental and flow details being model inputs. The monthly concentration of each water quality parameter also comprised model input. The model output was daily spatiotemporal variation in these parameters over a period of 476 days. This study also indicated that the occurrence of precipitation plays a major role in defining the water quality of a tropical lake. The heavy precipitation after a long gap, especially during the summer season, results in a large quantity of organic matter entering the lake through drains, thereby increasing the organic matter and phosphate in the water body, and subsequently resulting in high chlorophyll‐a concentrations in the lake. A reduced chlorophyll‐a concentration was observed during the heavy rains. The water quality fluctuations are more pronounced with precipitation, especially where polluted drains enter the lake. An improved water quality can be observed downstream, including increased dissolved oxygen and nitrate concentrations. Improved water quality was observed during the postmonsoon period, with increased salinity and dissolved oxygen concentrations, a finding that confirms generalized and specific conclusions can be achieved with the use of the WASP model.     

A disturbance observer based practical coordinated tracking controller for uncertain heterogeneous multi‐agent systems

This paper presents a coordinated tracking controller for multi‐agent systems. We assume that agents are uncertain, nonidentical, and affected by external disturbances. The information available to the tracking controller is a weighted sum of relative measurements. A coordinated tracking controller based on the disturbance observer, which is known as a robust output feedback controller, is designed so that the disturbances acting on agents are attenuated and at the same time the weighted sum of relative measurements approximately satisfies a differential equation defined by the leader's dynamics, which results in practical coordinated tracking. Systematic design procedures of the controller as well as numerical simulations are provided. Copyright © 2014 John Wiley & Sons, Ltd.     

The necessity of conducting to the end the activities of vector control in the onchocerciasis control program in west Africa: recall of the stakes and proposal of a minimum budget for the period 1998-2002

After a brief presentation of the Onchocerciasis Control Programme in West Africa (OCP), the authors realize the health and socioeconomic consequences that could follow a cessation of larvicide treatment before 2002 in the south-eastern and western extensions of the Programme. Taking into account that OCP activities are theoretically supported until 1997, but aware of financial constraints that will probably increase from now to 2002, this paper proposes an a minima estimation of the residual vector control activities for a "phasing out" spread out for five years (1998-2002). These estimations essentially concern the larvicide coverage, the insecticides used, the entomological surveillance, the logistical support and their financial aspects. As far as 48 U.S. $ million amount for 5 years are concerned, the budget allocated for vector control activities should not exceed the third of the global amount allocated to OCP for the actual fourth financial phase of the Programme (1992-1997).