Response of OceanSat II scatterometer winds in the Bay of Bengal circulation

Surface wind is one of the major forcing factors in any ocean circulation model. The response of satellite-derived OceanSat II scatterometer (OSCAT) winds during spring (February and March) 2010 in the Bay of Bengal (BOB) surface circulation is described in this study. Wind stress is calculated from wind speed derived from OSCAT by the bulk-aerodynamic formula. The Regional Ocean Modeling System is used in this study because it is a free-surface, terrain-following, primitive-equations ocean model widely used by the scientific community for a diverse range of applications. The model is used after a climatological simulation with Comprehensive Ocean–Atmosphere Data Set (COADS) forcing when the model simulation reached the annual cycle. The paper also carried out a comparative study of National Centers for Environmental Prediction (NCEP) forcing over the same time period. The comparison of model-simulated surface temperature to National Oceanic and Atmospheric Administration (NOAA) sea surface temperature (SST) indicates that meso-scale features in the BOB are resolved due to the finer resolution of this model. Comparisons of water mass characteristics to the available ARGO floats show good agreement in different locations within the BOB. This study confirms the usefulness of OSCAT winds in simulating the meso-scale feature in the BOB.     

In Vitro Structural and Functional Evaluation of Gold Nanoparticles Conjugated Antibiotics

Bactericidal efficacy of gold nanoparticles conjugated with ampicillin, streptomycin and kanamycin were evaluated. Gold nanoparticles (Gnps) were conjugated with the antibiotics during the synthesis of nanoparticles utilizing the combined reducing property of antibiotics and sodium borohydride. The conjugation of nanoparticles was confirmed by dynamic light scattering (DLS) and electron microscopic (EM) studies. Such Gnps conjugated antibiotics showed greater bactericidal activity in standard agar well diffusion assay. The minimal inhibitory concentration (MIC) values of all the three antibiotics along with their Gnps conjugated forms were determined in three bacterial strains, Escherichia coli DH5α, Micrococcus luteus and Staphylococcus aureus. Among them, streptomycin and kanamycin showed significant reduction in MIC values in their Gnps conjugated form whereas; Gnps conjugated ampicillin showed slight decrement in the MIC value compared to its free form. On the other hand, all of them showed more heat stability in their Gnps conjugated forms. Thus, our findings indicated that Gnps conjugated antibiotics are more efficient and might have significant therapeutic implications. Biswarup Saha and Jaydeep Bhattacharya authors contributed equally.     

Soliton solutions for nonlinear Calaogero-Degasperis and potential Kadomtsev-Petviashvili equations

This paper obtains the soliton solution for the Calogero-Degasperis and the potential Kadomtsev-Petviashvili equations. The tanh-coth and the tan-cot methods are used to retrieve the solutions. Finally, the ansatz method is also used to integrate these equations with any arbitrary constant coefficients. Finally, a few numerical simulations are also given.     

A novel mutual nearest neighbor based symmetry for text frame classification in video

In the field of multimedia retrieval in video, text frame classification is essential for text detection, event detection, event boundary detection, etc. We propose a new text frame classification method that introduces a combination of wavelet and median moment with k-means clustering to select probable text blocks among 16 equally sized blocks of a video frame. The same feature combination is used with a new Max-Min clustering at the pixel level to choose probable dominant text pixels in the selected probable text blocks. For the probable text pixels, a so-called mutual nearest neighbor based symmetry is explored with a four-quadrant formation centered at the centroid of the probable dominant text pixels to know whether a block is a true text block or not. If a frame produces at least one true text block then it is considered as a text frame otherwise it is a non-text frame. Experimental results on different text and non-text datasets including two public datasets and our own created data show that the proposed method gives promising results in terms of recall and precision at the block and frame levels. Further, we also show how existing text detection methods tend to misclassify non-text frames as text frames in term of recall and precision at both the block and frame levels.     

Quantitative analysis of morphological changes in yeast colonies growing on solid medium: the eccentricity and Fourier indices

The colony shape of four yeast species growing on agar medium was measured for 116 days by image analysis. Initially, all the colonies are circular, with regular edges. The loss of circularity can be quantitatively estimated by the eccentricity index, E_i, calculated as the ratio between their orthogonal vertical and horizontal diameters. E_i can increase from 1 (complete circularity) to a maximum of 1.17–1.30, depending on the species. One colony inhibits its neighbour only when it has reached a threshold area. Then, E_i of the inhibited colony increases proportionally to the area of the inhibitory colony. The initial distance between colonies affects those threshold values but not the proportionality, E_i/area; this inhibition affects the shape but not the total surface of the colony. The appearance of irregularities in the edges is associated, in all the species, not with age but with nutrient exhaustion. The edge irregularity can be quantified by the Fourier index, F_i, calculated by the minimum number of Fourier coefficients that are needed to describe the colony contour with 99% fitness. An ad hoc function has been developed in Matlab v. 7.0 to automate the computation of the Fourier coefficients. In young colonies, F_i has a value between 2 (circumference) and 3 (ellipse). These values are maintained in mature colonies of Debaryomyces, but can reach values up to 14 in Saccharomyces. All the species studied showed the inhibition of growth in facing colony edges, but only three species showed edge irregularities associated with substrate exhaustion. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of the shock-wave treatment on the dynamic strength of 38KhN3MFA steel

Effect of the shock-wave treatment on the dynamic strength of a 38KhN3MFA grade steel was studied in two different regimes—shock wave propagation and superdeep incorporation of ultrafine powder. In the first case, an increase in the dynamic strength is observed, related primarily to a decrease in the proportion of hard and brittle domains in the material as a result of the shock-wave action. The superdeep ultrafine powder incorporation produced no significant effects on the dynamic properties of steel.     

Electrical resistivity of polycarbonate/multiwalled carbon nanotube composites under varying injection molding conditions

Multiwalled carbon nanotube (MWCNT)‐filled polycarbonate composites were prepared by a corotating intermeshing twin‐screw extruder. The surface resistivities of compression‐ and injection‐molded specimens were quite different, the difference ranging from 10³ to 10⁷ Ω/sq at varying MWCNT concentrations. The surface resistivity of the injection‐molded specimen at 2 wt % loading varied up to 10⁵ Ω/sq in the specimen thickness direction and up 10⁴ Ω/sq in the polymer flow direction with respect to the gate. The difference in surface resistivity with the positions of injection‐molded specimen was confirmed with the morphology, which showed the difference in MWCNT number density (numbers/surface area). There was no significant effect on surface resistivity with injection pressure, holding pressure, and molding temperature. The specimens prepared at the injection speed of 13 mm/s showed surface resistivities 10³–10⁴ Ω/sq depending on the positions, which was comparable with the compression‐molded specimens, which had a surface resistivity of 10³ Ω/sq. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Microstructural and electrical characteristics of SiO2 doped ZnO-Bi2O3 varistors

Varistors in the new system ZnO-Bi₂O₃-SiO₂ were prepared through conventional ceramic processing route. The effect of sintering temperature and time (0·5 h to 2 h between 1000° and 1250°C) on the microstructure and current/voltage characteristics of the varistors of the new system were investigated and the results were compared with those of ZnO-Bi₂O₃ system varistors prepared. An increase in nonlinear coefficient (α) value was observed in the SiO₂ added varistors. The microstructure and the phase of the varistors were examined by means of SEM and XRD. The Zn₂SiO₄ spinel phase was found to be present in the intergranular region. The grain growth exponent was determined to be 2·5±0·2 and the activation energy for the ZnO grain growth was estimated to be 251±11 kJ/mol. These values were compared with those estimated for ZnO-Bi₂O₃ system varistors.     

Optical Solitons with Power Law Nonlinearity and Hamiltonian Perturbations: An Exact Solution

This paper studies the optical solitons with power law nonlinearity in presence of Hamiltonian perturbation terms. The perturbation terms that are taken into account are inter-modal dispersion, third order dispersion, self-steepening term and nonlinear dispersion. An exact 1-soliton solution is obtained by the solitary wave ansatz. Both bright and dark optical soliton solutions are obtained. The domain restrictions have also been identified in the process.     

Structure‐Based Design of Novel Human Toll‐like Receptor 8 Agonists

Toll‐like receptor (TLR)‐8 agonists activate adaptive immune responses by inducing robust production of T helper 1‐polarizing cytokines, suggesting that TLR8‐active compounds might be promising candidate vaccine adjuvants. Recently, a C2‐butyl furo[2,3‐c]quinoline was reported with purely TLR8 agonistic activity. This compound was successfully co‐crystallized with the human TLR8 ectodomain, and the co‐crystal structure revealed ligand‐induced reorganization of the binding pocket of TLR8. The loss of a key hydrogen bond between the oxygen atom of the furanyl ring of the agonist and Thr 574 in TLR8 suggested that the furan ring is dispensable. Employing a disconnection strategy, 3‐ and 4‐substituted aminoquinolines were investigated. Focused structure‐based ligand design studies led to the identification of 3‐pentyl‐quinoline‐2‐amine as a novel, structurally simple, and highly potent human TLR8‐specific agonist (EC₅₀=0.2 μM ). Preliminary evaluation of this compound in ex vivo human blood assay systems revealed that it retains prominent cytokine‐inducing activity. Together, these results indicate the suitability of this compound as a novel vaccine adjuvant, warranting further investigation.