Isolation and identification of phosphate‐solubilizing microorganisms and distribution of orthophosphate in different seasons from sewage‐fed East Kolkata Wetland

This study focused on isolation and identification of possible phosphate‐solubilizing bacteria (PSB ) from the sewage‐fed East Kolkata Wetland (EKWL ), a prospective water resource for pisciculture. In addition, different limnological parameters have been correlated with orthophosphate and seasonal variations. PSB have been isolated in Pikovskaya medium and identified morphologically and biochemically and finally analysed by 16S rDNA gene sequence. Limnological studies involving temperature (potentiometric), pH (potentiometric), dissolved oxygen (iodometric), ammonia‐nitrogen (spectrophotometric) and orthophosphate (spectrophotometric) concentrations were conducted. The results of this study established the presence of Bacillus megaterium , a potential PSB in EKWL . The activity of B. megaterium is also supported by the seasonal orthophosphate variations. The changes in concentration of other limnological parameters were also prominent. The water quality parameters of temperature (r  = 0.886), dissolved oxygen (r  = 0.729) and ammonia‐nitrogen (r  = 0.396) concentrations exhibited a positive correlation with orthophosphate and a negative correlation with pH (r  = ?0.699). The B. megaterium obtained in this study, exhibited a significant alteration in regard to orthophosphate content and relationships with other factors. Further experiment on the soluble phosphorus solubilization potential of B. megaterium revealed the biological availability of phosphorus was increased by threefold after 120 hr of incubation, with the decreasing pH value, although the phytase activity was 0.419 U/ml. PSB have a vital function in plant nutrition in supplying phosphate, essential nutrients and its uptake results in appropriate functioning and metabolism of different aquatic plants and organisms. PSB are competent biofertilizer to amplify aquaculture production for sustainable development.     

Small-sample properties of some parametric and nonparametricmethods for detection of signals by Monte Carlo simulation

The paper considers the estimation of the number of signals in a multichannel time-series model. The author uses different information theoretic criteria and some nonparametric methods to detect the number of signals and compare their small-sample properties by Monte Carlo simulation study     

Radiation induced graft copolymerization V. Graft copolymerization of methyl acrylate onto nylon-6 fiber

The radiation induced graft copolymerization of methylacrylate onto nylon-6 fiber at room temperature and in nitrogen medium was investigated. The effects of monomer, dose rate, inhibitor etc. on the graft yield have been investigated. The effect of solvents on the rate of grafting was studied from which the chain-transfer constant (C_s) of the solvent has been evaluated. Addition of certain inorganic salts was found to act as scavengers. The value of G_b, the number of branches per 100 eV of energy absorbed in the substrate polymer, was calculated. The density, moisture regain, alkali solubility, dyeability and thermal properties of the grafted nylon-6 fiber have been evaluated.     

Effect of addition of surfactants on the rheology of gels from methylcellulose in N,N‐dimethylformamide

The effect of highly substituted cationic cetyl trimethyl ammonium bromide (CTAB), less substituted cationic hexadodecyl ammonium bromide (HDAB), CTAB‐ and HDAB‐modified montmorillonite (CTABMONT and HDABMONT), and nonionic surfactants on the rheological properties of methylcellulose (MC) N,N‐dimethylformamide (DMF) gels have been studied. The storage modulus of the MC‐MDF gels increases with an increase in frequency. During the frequency scan, the storage and loss modulus of MC‐DMF gel crosses over each other at two different frequencies. At the crossover points, the loss tangent is found to be unity. The addition of CTAB‐ and HDAB‐modified nanofiller increases in the gel strength of MC‐DMF gel. The storage modulus of MC‐DMF gel in the presence of CTABMONT is found to be higher than that of CTAB‐modified MC‐DMF gel. Whereas, the storage modulus of MC‐DMF gel in the presence of HDABMONT is lower than that of HDAB‐modified MC‐DMF gel. On the other hand, the addition of nonionic surfactant (Brij78) decreases the gel strength. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Transient surface response of layered isotropic and anisotropic half-spaces with interface cracks: SH case

The transient response of the surface of a layered isotropic or anisotropic half-space, with two interface cracks, excited by a plane SH-wave is investigated. The incident field is taken as a bulk wave. The governing equations along with boundary, regularity and continuity conditions across the interface are reduced to a coupled set of singular integral equations. Solutions of these equations are obtained by expanding unknown crack opening displacement (COD) in terms of a complete set of Chebyshev polynomials. As sample problems, the surface response of isotropic as well as anisotropic layered half-spaces with and without crack interactions is computed

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Résumé On étudie la réponse transitoire de la surface d'un demi-espace à couches successives isotropes ou anisotrope dans le cas de deux fissures d'interfaces abordées par une onde SH plane. Le champ incident est assimilé à une onde de base. On ramène les équations directrices ainsi que les conditions aux limites, et les conditions de régularité et de continuité, à un jeu d'équations intégrales singulières couplées. Les solutions de ces équations sont obtenues en procédant à une extension d'un COD inconnu sous forme d'un ensemble de polynomes de Chebyshev. A titre d'exemple type, on calcule la réponse de surface de demi-espaces en couches, de caractère isotrope et de caractère non isotrope, avec ou sans interactions de fissures

     

Quantitative evaluation of shape of image on photoresist of squareapertures

Simulation of images of two-dimensional structures in optical lithography is considered to have become quite important with the patterning of near-micrometer geometries in complex structures encountered in VLSI. Here, the results are presented of theoretical computations performed to calculate the aerial image of square apertures in a projection system using a partially coherent light source. The resist has been modeled by its sensitivity curve in order to compute the image profile on the resist after development. A figure of merit (FOM) has been proposed that quantifies the shape of the aerial as well as the resist image. Such an FOM has been proposed that can be used very effectively to optimize a lithographic process     

Development and Validation of Method for Determination of In Vitro Release of Retinoic Acid from Creams

The objective of this study was to develop and validate an in vitro test method that can be used as a tool for accessing batch-to-batch uniformity of finished topical products. The studies were performed by utilizing topical creams containing the 13-cis isomer of retinoic acid. Various physicochemical factors which may affect drug release from topical cream formulations were evaluated including drug concentration, internal phase droplet size distribution, viscosity and the composition of the emulsion internal and external phases. Utilizing a modified Franz diffusion cell with a cellulose membrane, the in vitro drug release profile from various cream formulations was established

The effect of varying the concentrations of various key ingredients by 30% does affect the viscosities and release rates compared to a standard formulation. However, there is no correlation between the viscosities and the release rates. No significant differences in pH and droplet size distribution were observed in these cream formulations compared to a standard formulation. The oil phase volume ratio appears to have the largest influence on the in vitro release of the drug. Intra- and inter-batch comparisons of the finished cream products show reproducible release profiles. Based on the results obtained in this study, when used together, both in vitro release and viscosity measurements may be useful as tools to assess batch-to-batch uniformity and consistent manufacturing of the finished cream product     

Treating congenital hypothyroidism: maximum age limit up to which a socially compatible child is expected

Salmonella osteomyelitis is an uncommon disease, usually associated with sickle cell anemia and other hemoglobinopathies, as well as with other disease states. In this case, osteomyelites was apparently caused by hematogenous spread of an enteric infection by Salmonella enteritidis. Bone involvement, in vertebral bodies, was resolved after prolonged clinical treatment with antibiotics. We discuss the pathogeny and compare the findings of four case with others related in literature.