Chemical bath deposition of different phases of copper selenide thin films by controlling bath parameters

In the preparation of copper selenide thin films using chemical bath deposition (CBD) technique, it is observed that the pH of the final reacting mixture is the major factor controlling the composition of the film. Thin films of cubic Cu_2−xSe and tetragonal Cu₃Se₂, of band gaps 2.20 and 2.83 eV, respectively, have been prepared using the CBD technique by adjusting the bath parameters like pH, temperature and the ratio between copper and selenium atoms in the reaction bath. X-ray diffraction analysis is used as the major tool for identification of these phases. The results have been confirmed using XPS, ICP and absorption studies.     

Study of the feasibility of involving male student volunteers in case holding in an urban tuberculosis programme

AIMS: To investigate the effect of the angiotensin converting enzyme inhibitor, benazepril, on pulmonary function. METHODS: We investigated the influence of benazepril, on lung function and the interaction with inhaled salbutamol (0.1 to 6.6 mg) and histamine (0.03 to 30.69 g l-1) in normal subjects. Benazepril 20 mg, salbutamol 8 mg, propranolol 160 mg, and placebo were given orally once daily over 10 days. RESULTS: On day 8, there was no difference in the area under the salbutamol dose-response curves between benazepril, placebo and oral salbutamol (P > 0.05), propranolol shifted the curves to the right (P < 0.05). On day 10, histamine challenge resulted in following PD35sGaw values (geometric mean and 95% CI): with placebo 1.02 (0.95-1.09) g l-1, benazepril 1.04 (0.99-1.08), salbutamol 1.19 (1.13-1.25), propranolol 0.57 (0.50-0.65). CONCLUSIONS: Benazepril had no influence on baseline lung function, caused no interaction with inhaled salbutamol and the bronchial response to histamine was similar to placebo. However, our findings in normal subjects cannot be extrapolated automatically to asthmatics.     

A Unified Approach to the Sizing and Control of Energy Storage Systems

Grid operation and planning challenges arising out of large-scale integration of renewable power can to a large extent be solved by the use of energy storage systems (ESSs). The type and size of storage to be used may be decided by the amount of fluctuating power the storage charges or discharges to attain its objective. Storage systems can be used as single devices or as hybrid systems where two or more devices complement the working of each other. The objective of this paper is to find an accurate power and energy sizing methodology for storage devices working in a single or hybrid arrangement such that the power fed to the grid from a wind turbine generator is regulated to a constant value. A strategy for sizing of a hybrid ESS is proposed by choosing the long-term storage to be a battery energy system and the short-term device to be a flywheel and using frequency analysis techniques. In the case of flywheel energy storage system, the inertia and the gain of an integral controller applied to an induction-machine-based flywheel are obtained. The simulations are done in MATLAB.     

Modeling of the zero-bias resistance-area product of long wavelength infrared HgCdTe-on-Si diodes fabricated from molecular beam epitaxy-grown epitaxial layers

The electrical effects of dislocations has been studied by modeling zero-bias resistance-area product (R₀A) of long wavelength infrared diodes fabricated in molecular beam epitaxy (MBE)-grown HgCdTe-Si epitaxial films. Results show that dislocations influence both 40 K and 78 K R₀A products in high dislocation density (HgCdTe/Si) material. In low dislocation density samples (HgCdTe/CdZnTe), the variations in 78 K R₀A are limited by the composition (x) variations in Hg_1-xCd_xTe material, whereas dislocation contribution dominates the variations at 40 K. The origin of relatively large spread in 40 K R₀A in both types of samples is traced to the statistical variations in the core charges of dislocations. It is concluded that additional alternatives besides the reduction of dislocation density (such as control of core charges), may also need attention in order to make Si a viable substrate material for the growth of HgCdTe epitaxial layers suitable for devices operating at 40 K.     

Constrained cascade generalization of decision trees

While decision tree techniques have been widely used in classification applications, a shortcoming of many decision tree inducers is that they do not learn intermediate concepts, i.e., at each node, only one of the original features is involved in the branching decision. Combining other classification methods, which learn intermediate concepts, with decision tree inducers can produce more flexible decision boundaries that separate different classes, potentially improving classification accuracy. We propose a generic algorithm for cascade generalization of decision tree inducers with the maximum cascading depth as a parameter to constrain the degree of cascading. Cascading methods proposed in the past, i.e., loose coupling and tight coupling, are strictly special cases of this new algorithm. We have empirically evaluated the proposed algorithm using logistic regression and C4.5 as base inducers on 32 UCI data sets and found that neither loose coupling nor tight coupling is always the best cascading strategy and that the maximum cascading depth in the proposed algorithm can be tuned for better classification accuracy. We have also empirically compared the proposed algorithm and ensemble methods such as bagging and boosting and found that the proposed algorithm performs marginally better than bagging and boosting on the average.     

Chronic phenytoin induced impairment of learning and memory with associated changes in brain acetylcholine esterase activity and monoamine levels

Groups of adult, male, Wistar rats were administered phenytoin (DPH) at 5, 12.5, 25, 50, or 75 mg/kg i.p. for 21 days. The learning and memory of these rats were assessed using the T-maze and passive avoidance tests. The plasma DPH levels, acetylcholine esterase (AChE) activity in different brain regions, and the levels of monoamines in the hippocampus were measured. The results indicate that DPH below the therapeutic plasma level did not significantly impair learning and memory. Correspondingly, no changes were noted in the brain 5-HT or AChE activity. However, DPH, at therapeutic plasma concentrations (i.e., 10.5 micrograms/ml in the dosage range of 50 and 75 mg/kg, respectively), significantly impaired learning and memory in rats. The impaired learning and memory functions were associated with increased 5-HT levels and decreased AChE activity in the hippocampus. With a dose of 75 mg/kg DPH, there was a reduction in the AChE activity in the striatum, in addition to hippocampus. It is conjectured that the neurochemical changes brought about by DPH at therapeutic plasma levels may account for the impairment of learning, memory, and cognitive functions in epilepsy.     

Generation of sign Walsh spectra from disjoint cubes of Boolean functions

A new algorithm is given that converts a reduced representation of Boolean functions in the form of disjoint cubes to sign Walsh spectra. Since the known algorithms that generate sign Walsh spectra always start from the truth table of Boolean functions, the method presented computes faster with a smaller computer memory. The method is especially efficient for such Boolean functions that are described by only few disjoint cubes.     

Estimating changes in traffic intensity for M/M/1 queueing systems

In this paper, the principle of maximum likelihood is used to estimate change point of traffic intensity for the M/M/1 queueing model. The procedure is illustrated with a simulated example for each possible change in traffic intensity.     

Procedural outcome and follow-up results of balloon angioplasty versus new device interventions for treatment of true bifurcation stenoses

Strategies for dilatation of bifurcation stenoses have continued to evolve over the past several years. However, there is limited experience on the efficacy of various nonballoon interventional devices and their results in comparison with balloon angioplasty. We, therefore, analysed our data in 72 patients of coronary artery disease with true bifurcation stenoses with balloon angioplasty or new device interventions (NDI). All patients underwent dilatation of both the primary vessel and side branch ostial stenosis. Balloon angioplasty using double guidewire with sequential or simultaneous (kissing balloon) balloon inflation in the two vessels was performed in 42 patients. Thirty patients underwent NDI, using directional coronary atherectomy (DCA) in 12, rotablation in 6 and elective coronary stents in 12 patients. There were no significant differences in the baseline clinical and angiographic variables between patients in the two groups. While the preprocedural luminal diameter stenosis was similar, the residual stenosis was significantly less, both in the primary vessel and side branch, after NDI compared to balloon angioplasty. The procedure was successful in 96.6 percent patients treated with NDI and 83.3 percent with balloon angioplasty (p < 0.01) with relief of obstruction in both branches without any major complications. Freedom from subsequent coronary events in the form of angina, myocardial infarction, PTCA, bypass graft surgery of death was significantly more, both at 6 months (92% versus 65.6%, p < 0.001) and 12 months (81.8% versus 53.1%, p < 0.001) in the group of patients treated with NDI compared to balloon angioplasty. It is, therefore, concluded that NDI including DCA, rotablation and elective stenting are associated with higher rate of success, lesser complications and better event-free survival in comparison to balloon angioplasty for treatment of true bifurcation stenoses.