Contamination of surface and potable water in South Asia by Salmonellae: Culture-independent quantification with molecular beacon real-time PCR

Low numbers (15-100 CFU) of Salmonella in food or water may pose a public health risk. The management of infections caused by Salmonella spp. during outbreaks or forecasting of contamination of aquatic resources largely depends on rapid, sensitive and accurate diagnostic in few hours. In this study, a real-time PCR assay in Molecular-Beacon format was developed and culture-independent quantitative enumeration of Salmonella spp. in surface and potable water is being reported for the first time from northern part of India. Molecular Beacon was designed in highly conserved region of invA gene (present in wide range of Salmonella serotypes including all subspecies) encoding an essential component of the invasion associated specialized type Ø protein secretion apparatus for detection of Salmonella spp. in water. The assay could detect directly 10 and 1 genomic equivalent of Salmonella typhimurium ATCC 14028 per PCR with detection probability of 100 and 20%, respectively. Further, the assay could detect 10 CFU/PCR or more of reference strain (S. typhimurium ATCC 14028) without any enrichment in the presence of 10⁸ CFU ml^− 1 of non-pathogenic E. coli (E. coli DH5α) with 100% detection probability. The assay could enumerate Salmonella spp. in surface (n = 40) and potable waters (n = 10) directly (without enrichment). Results indicate that northern India is at high risk of developing Salmonella borne infections. Further, real-time PCR assay in Molecular Beacon format can be used for identification of critical contamination points in natural water resources and potable water distribution systems, necessary to implement vaccination plan timely for prevention of waterborne outbreaks caused by Salmonella spp.     

Fuzzy set based cost model of additive manufacturing with specific example of selective laser sintering

A fuzzy set based cost model for additive manufacturing is proposed. The model is illustrated through an example of selective laser sintering (SLS), a commonly used additive manufacturing (AM) process. Initially, a deterministic cost model is developed. It is then converted to a fuzzy set based model by considering uncertainty in build time estimation and cost components. For the specific case of SLS, a build time estimation procedure is developed as a part of the cost model. A method to evaluate the reliability of the cost estimate in AM and its significance is also introduced. The cost model is illustrated through two examples of products manufactured by SLS.

     

Optimization of A-TIG process parameters using response surface methodology

In the present work, the influence of process parameters such as welding current (I), welding speed (S), and flux coating density (F) on different aspects of weld bead geometry for example depth of penetration (DOP), bead width (BW), depth to width ratio (D/W), and weld fusion zone area (WA) were investigated by using the central composite design (CCD). 9–12% Cr ferritic stainless steel (FSS) plates were welded using A-TIG welding. It was observed that all input variables have a direct influence on the DOP, BW, and D/W. However, flux coating density has no significant effect on WA. Mathematical models were generated from the obtained responses to predict the weld bead geometry. An optimized DOP, BW, D/W, and WA of 6.95?mm, 8.76?mm, 0.80, and 41.99?mm², respectively, were predicted at the welding current of 213.78 A, the welding speed of 96.22?mm/min, and the flux coating density of 1.99?mg/cm². Conformity test was done to check the practicability of the developed models. The conformity test results were in good agreement with the predicted values. Arc constriction and reversal in Marangoni convection were considered as major mechanisms for the deep and narrow weld bead during A-TIG welding.     

Nanoparticle‐Enhanced Silver‐Nanowire Plasmonic Electrodes for High‐Performance Organic Optoelectronic Devices

Improved performance in plasmonic organic solar cells (OSCs) and organic light‐emitting diodes (OLEDs) via strong plasmon‐coupling effects generated by aligned silver nanowire (AgNW) transparent electrodes decorated with core–shell silver–silica nanoparticles (Ag@SiO₂NPs) is demonstrated. NP‐enhanced plasmonic AgNW (Ag@SiO₂NP–AgNW) electrodes enable substantially enhanced radiative emission and light absorption efficiency due to strong hybridized plasmon coupling between localized surface plasmons (LSPs) and propagating surface plasmon polaritons (SPPs) modes, which leads to improved device performance in organic optoelectronic devices (OODs). The discrete dipole approximation (DDA) calculation of the electric field verifies a strongly enhanced plasmon‐coupling effect caused by decorating core–shell Ag@SiO₂NPs onto the AgNWs. Notably, an electroluminescence efficiency of 25.33 cd A^?1 (at 3.2 V) and a power efficiency of 25.14 lm W^?1 (3.0 V) in OLEDs, as well as a power conversion efficiency (PCE) value of 9.19% in OSCs are achieved using hybrid Ag@SiO₂NP–AgNW films. These are the highest values reported to date for optoelectronic devices based on AgNW electrodes. This work provides a new design platform to fabricate high‐performance OODs, which can be further explored in various plasmonic and optoelectronic devices.     

Hybrid Boundary Integral-Generalized (Partition of Unity) Finite-Element Solvers for the Scalar Helmholtz Equation

Finite-element-based techniques are one of the most popular methods used to model electromagnetic field behavior, but rely on the underlying tesselation to construct the ansatz space. Recently, Babuska and his colleagues developed the generalized finite-element method (GFEM), which overcomes this constraint and admits a larger class of basis functions. Application of this technique has been largely restricted to Poisson systems. In this paper, we explore the applicability of this technique to two-dimensional Helmholtz systems. We investigate methods necessary to impose various boundary conditions. We use this analysis to build the framework for hybridizing boundary integral techniques with GFEM, thus imposing an exact boundary condition to truncate the computational domain. We validate the results against analytical data for canonical geometries, and we demonstrate h and p convergence of this technique. Finally, to further validate the proposed approach for complex scatterers, we augment GFEM with perfectly matched layers, and compare it against the results obtained by using boundary integral GFEM     

Geospatial analysis of terrain through optimized feature extraction and regression model with preserved convex region

In this paper, cat optimization algorithm for feature extraction in satellite image has been proposed. In cat optimization, cost function computes the pixel in the satellite image to preserve the boundary shape and avoid non-convex part of the contour of the image. However, the existing feature extraction optimization algorithm measures the distinct data framework and thematic information to insight land cover such as waterbody, urban and vegetation. The land cover is obtained from different optimized feature extraction algorithms never provide proper boundary shape and land feature. Furthermore, the proposed cat optimized algorithm distinguishes the inner, outer and extended boundary along with the land cover. The cat-optimised algorithm for low and high-resolution satellite image shows the better result of 85%, with the preserved convex region when compared with the existing feature extraction algorithm such as fuzzy and Particle Swarm Optimization (PSO).     

Characterisation of acidic groups in oxycelluloses. II. Estimation of carboxyl groups and lactones by iodometric method

A differentiation between free carboxyl and various lactone groups in oxycelluloses was carried out based on the variation in their reaction rates with KI–KIO₃ solution. An attempt has been made to identify the various lactone groups present by comparison of the results of different oxycelluloses as well as study on some model compounds. A characteristic and group spectrum was determined for each oxycellulose. On blocking the free carboxyl groups by zinc acetate treatment, the results for the nature and amounts of various lactones present are in good agreement with the results for oxycelluloses themselves. Sodium borohydride treatment for 120 hr has been found to be incapable of reducing all the lactones present. An appreciable decrease in the value for glucono-δ-lactone was observed, whiles glucuronic acid lactone was only partially attacked. Treatment with chlorous acid resulted in an increase in the values for free carboxyl as well as lactones for all oxycelluloses.