Resputtering-induced chemical inhomogeneity during the growth of highT c superconductor thin film

HighT _c films belonging to Y-Ba-Cu-O, Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O systems have been fabricated by reactive sputtering of single targets in a planar magnetron and Ar + O₂ sputtering atmosphere. Although it was possible to deposit films of correct composition, resputtering related composition variation was a problem. The key to obtaining correct chemistry was a proper control of the deposition parameters. The pressure and oxygen content of the sputtering gas were found to be the most critical parameters. Results of the variation of these parameters on the cation chemistry are presented in this paper. Results from Monte-Carlo simulation of the sputtering process are also presented showing that low pressure and oxygen content of the sputtering gas result in a higher yield of energetic reflected neutrals which can cause compositional variation in the film mainly due to preferential sputtering of the growing film. The effect was particularly noticeable directly underneath the target. The energetic particle bombardment can be controlled by using moderately high pressures and low oxygen concentration in the gas.     

Pediatric flexible bronchoscopy

Between 1993-1996, 200 pediatric flexible bronchoscopies were performed. Indications were: chronic cough (158 children), persistent pulmonary infiltrates (89), recurrent stridor (28), suspected tracheobronchial foreign body (20), suspected tuberculosis (17) and hemoptysis (3). Some children had more than 1 indication. 124 patients were boys (mean 4.18 +/- 2.86 years; range 1 month-15 years) and 76 were girls (mean 4.39 +/- 2.7 years; range 4 months-15 years). The procedure included direct vision recorded by video-camera and bronchoalveolar lavage; the lavage fluid was sent for culture, Gram and Ziehl-Nielsen strains and for cytology. There were a few minor side effects: mild stridor which resolved within a few hours (10 children) and transient fever (3). This simple, flexible instrument was effective and helpful in the diagnosis and treatment of children with respiratory symptoms in a secondary hospital facility.     

新型本质阻燃高分子材料研究进展

综述了近年来国内外新型本质阻燃高分子材料的研究现状。简述了几种本质阻燃高分子材料如环氧树脂(EP)、聚酯(PET)、聚酰胺(PA)等阻燃材料的制备方法及通过实验对其性能的研究,阐述了几种自身具有阻燃性能的新型环保高分子材料,总结了现阶段阻燃高分子材料的制备方法和存在的不足,并提出了阻燃高分子材料的发展趋势。     

FtsY, the prokaryotic signal recognition particle receptor homologue, is essential for biogenesis of membrane proteins

In mammalian cells, many secretory proteins are targeted to the endoplasmic reticulum co-translationally, by the signal recognition particle (SRP) and its receptor. In Escherichia coli, the targeting of secretory proteins to the inner membrane can be accomplished post-translationally. Unexpectedly, despite this variance, E. coli contains essential genes encoding Ffh and FtsY with a significant similarity to proteins of the eukaryotic SRP machinery. In this study, we investigated the possibility that the prokaryotic SRP-like machinery is involved in biogenesis of membrane proteins in E. coli. The data presented here demonstrate that the SRP-receptor homologue, FtsY, is indeed essential for expression of integral membrane proteins in E. coli, indicating that, in the case of this group of proteins, FtsY and the mammalian SRP receptor have similar functions.     

Phenolic constituents in major fractions of tropical rapeseed

Phenolic constituents in major fractions such as seed, cotylendons and hulls of commercial rapeseed varieties Ganyou-5, Westar, Raya-brown and Raya yellow grown under tropical conditions in Pakistan, were determined. Quantitative determination in percentage of sinapine, catechin, tannic acid and total phenolics as well as in absorption units at 550 nm of procyanidine, proanthocyanidine and flavan-4-ols in relation to different extractants such as methanol, methanol-HCl and their totals, were made. These varieties and their fractions widely varied in different phenolic constituents in respect of extractants used. Hulls of all cultivars contained higher levels of catechin, procyanidine, pronanthocyanidine and flavan-4-ols while lower amounts of sinapine, tannic acid and total phenols than the cotylendons. Cotylendons and hulls in seeds of raya-brown were exceptionally high in procyanidine.     

Soluble soybean polysaccharide/TiO2 nanocomposites: Biological activity,release behavior,biodegradability, and biosafety

This study aimed to produce and characterize eco-friendly SSPS nanocomposites incorporated with various concentrations of TiO₂ nanoparticles (NPs) (1%, 3%, and 7%). The antimicrobial activity of the nanocomposite films against five strains of pathogenic bacteria was examined. Salmonella typhi PTCC 1609 was the most sensitive species to TiO₂ NPs at concentrations equal to the synthetic antibiotic. The migration of TiO₂ to ethanol and acetic acid, as two food simulants increased when the initial nano-TiO₂ content increased. The release profiles for TiO₂ in two simulants of ethanol and acetic acid indicated a non-Fickian release, and the release kinetics were concentration-dependent. SSPS/TiO₂ nanocomposites degraded easily and thus have the potential to be applied as an eco-friendly packaging system. Oral administration of doses of 1, 12.5, 25, 50, and 75 mg/kg TiO₂ revealed that the dose of 50 and 75 mg/kg increased malondialdehyde (p < .001) concentration in the liver tissue. In addition, it decreased glutathione (p < .001) concentration in the liver tissue.     

A Reliable Stochastic Numerical Analysis for Typhoid Fever Incorporating With Protection Against Infection

In this paper, a reliable stochastic numerical analysis for typhoid fever incorporating with protection against infection has been considered. We have compared the solutions of stochastic and deterministic typhoid fever model. It has been shown that the stochastic typhoid fever model is more realistic as compared to the deterministic typhoid fever model. The effect of threshold number T* hold in stochastic typhoid fever model. The proposed framework of the stochastic non-standard finite difference scheme (SNSFD) preserves all dynamical properties like positivity, bounded-ness and dynamical consistency defined by Mickens, R. E. The stochastic numerical simulation of the model showed that increase in protection leads to low disease prevalence in a population.     

Ferroelectric,dielectric, magnetic,structural and photocatalytic properties of Co and Fe doped LaCrO3 perovskite synthesized via micro-emulsion route

In the present investigation, La_1-xCo_xCr_1-yFe_yO₃ (x,y = 0.0, 0.12, 0.36, 0.60) perovskite was fabricated via a facile micro-emulsion route. The synthesized perovskites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques to examine the effect of Co and Fe ions on the physico-chemical properties. The ferroelectric, dielectric, and magnetic properties of La_1-xCo_xCr_1-yFe_yO₃ were changed significantly as a function of dopants contents (Co and Fe ions). Outcomes revealed that the dielectric, ferroelectric and magnetic properties of LaCrO₃ perovskite can be tuned significantly via Co and Fe doping and La_0.40Co_0.60Cr_0.40Fe_0.60O₃ have potential for photocatalytic dye removal under (visible) light expoure. The photocatalytic activity (PCA) of the pristine LaCrO₃ and La_0.40Co_0.60Cr_0.40Fe_0.60O₃ photocatalyst was evaluated under (visible) light irradiation for crystal violet (CV) dye. Experimental results revealed that La_0.40Co_0.60Cr_0.40Fe_0.60O₃ photocatalyst degrdae almost 77.21% CV dye with the rate constant value of 0.01475 min^?1. In the presence of isopropyl alcohol (IPA) scavenger, the PCA of the La_0.40Co_0.60Cr_0.40Fe_0.60O₃ photocatalyst and rate constant value of the photocatalytic reaction decreased to 32.5% and 0.00491 min^?1, suggesting the superoxide as main active specie. Results revealed that Co and Fe doping doped material is efficient for photocatalytic presentations under solar light expoure.