Tangible nanocomposites with diverse properties for heart valve application

Cardiovascular disease claims millions of lives every year throughout the world. Biomaterials are used widely for the treatment of this fatal disease. With the advent of nanotechnology, the use of nanocomposites has become almost inevitable in the field of biomaterials. The versatile properties of nanocomposites, such as improved durability and biocompatibility, make them an ideal choice for various biomedical applications. Among the various nanocomposites, polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane, bacterial cellulose with polyvinyl alcohol, carbon nanotubes, graphene oxide and nano-hydroxyapatite nanocomposites have gained popularity as putative choices for biomaterials in cardiovascular applications owing to their superior properties. In this review, various studies performed utilizing these nanocomposites for improving the mechanical strength, anti-calcification potential and hemocompatibility of heart valves are reviewed and summarized. The primary motive of this work is to shed light on the emerging nanocomposites for heart valve applications. Furthermore, we aim to promote the prospects of these nanocomposites in the campaign against cardiovascular diseases.     

Identifying research facilitators in an emerging Asian Research Area

We introduce a novel set of metrics for triadic closure among individuals or groups to model how co-authorship networks become more integrated over time. We call this process of triadic, third-party mediated integration, research facilitation. We apply our research facilitation or RF-metrics to the development of the Pan-Asian SNP (PASNP) Consortium, the first inter-Asian genomics network. Our aim was to examine if the consortium catalyzed research facilitation or integration among the members and the wider region. The PASNP Consortium is an ideal case study of an emerging Asian Research Area because its members themselves asserted a regional Asian identity. To validate our model, we developed data mining software to extract and match full author and institutional information from the PDFs of scientific papers.     

Statistical analysis of mammographic features and its classification using support vector machine

This study aims at designing a support vector machine (SVM)-based classifier for breast cancer detection with higher degree of accuracy. It introduces a best possible training scheme of the features extracted from the mammogram, by first selecting the kernel function and then choosing a suitable training-test partition. Prior to classification, detailed statistical analysis viz., test of significance, density estimation have been performed for identifying discriminating power of the features in between malignant and benign classes. A comparative study has been performed in respect to diagnostic measures viz., confusion matrix, sensitivity and specificity. Here we have considered two data sets from UCI machine learning database having nine and ten dimensional feature spaces for classification. Furthermore, the overall classification accuracy obtained by using the proposed classification strategy is 99.385% for dataset-I and 93.726% for dataset-II, respectively.     

Minimizing total weighted tardiness on a batch-processing machine with non-agreeable release times and due dates

This study considers the scheduling problem observed in the burn-in operation of semiconductor final testing, where jobs are associated with release times, due dates, processing times, sizes, and non-agreeable release times and due dates. The burn-in oven is modeled as a batch-processing machine which can process a batch of several jobs as long as the total sizes of the jobs do not exceed the machine capacity and the processing time of a batch is equal to the longest time among all the jobs in the batch. Due to the importance of on-time delivery in semiconductor manufacturing, the objective measure of this problem is to minimize total weighted tardiness. We have formulated the scheduling problem into an integer linear programming model and empirically show its computational intractability. Due to the computational intractability, we propose a few simple greedy heuristic algorithms and meta-heuristic algorithm, simulated annealing (SA). A series of computational experiments are conducted to evaluate the performance of the proposed heuristic algorithms in comparison with exact solution on various small-size problem instances and in comparison with estimated optimal solution on various real-life large size problem instances. The computational results show that the SA algorithm, with initial solution obtained using our own proposed greedy heuristic algorithm, consistently finds a robust solution in a reasonable amount of computation time.     

Fischer–Tropsch Synthesis: Studies on the Effect of Support Doping with Si,Mn and Cr on the Selectivity to Alcohols in Ceria Supported Cobalt Catalysts

Mn and Cr doped CeSi mixed oxides were used as supports for Co and tested for CO hydrogenation. Co/CeSi was found to be more active and significantly more selective to n-alcohols/olefins. An increasing selectivity to n-alcohols and decreasing selectivity to olefins as a function of time on stream was also observed, suggesting a trade-off between those two products. Addition of Mn led to similar behavior, although at slightly lower conversions. Addition of Cr, however, considerably suppressed n-alcohol formation, while it kept selectivities to olefins within a 20–30 % range over more than 250 h of testing, indicating either higher alcohol dehydration activity, or that the presence of Cr ions lowered the hydrogenating activity of Co. The present work indicates that enhanced contact area between Co and the reducible support is likely a key factor for enhancing selectivity to alcohols.     

Investigation of structural,optical, and thermal properties of 2-amino-4,6-dimethylpyrimidine benzoic acid (2APB) single crystal for non-linear optical (NLO) applications

The 2-amino-4,6-dimethylpyrimidine benzoic acid (2APB) single crystal has been successfully grown by the slow evaporation method by using water as a solvent. The single-crystal X-Ray diffraction (SXRD) analysis gives knowledge about the structure and morphology of the 2APB crystal. The Powder X-ray Diffraction (PXRD) pattern of grinded 2APB crystal was compared with standard CIF file and the peaks were indexed with their corresponding miller indices (hkl). The crystalline perfection of the grown 2APB single crystal was analysed using high-resolution X-ray diffraction (HR-XRD) measurement. The various functional groups and their vibrational assignments were studied using the Fourier-transform infrared (FTIR) spectrum analysis. The 2APB crystal has a lower cut-off wavelength of 325 nm, which is evident from the UV–visible–NIR analysis. The defects and etch pit density of 2APB crystal were examined using chemical etching studies. The 2APB crystal was thermally stable up to 140 °C, which was evident from the thermogravimetric (TG) and differential thermal analysis (DTA). The photoconductivity analysis was carried out to calculate the photo and dark current values. The laser damage threshold (LDT) value was determined using a 532 nm Nd:YAG laser in single shot mode. The third-order non-linear optical (NLO) susceptibility (χ⁽³⁾) value was calculated from Z-scan technique, which involves open and closed aperture measurements.

     

Relation of the concentration-time product to uptake and mortality in Sitophilus granarius treated with methyl bromide

Uptake of methyl bromide was greater at high concentrations with an exposure period of 2 hr than at lower concentrations with an exposure period of 5 hr, but mortality did not increase accordingly. Some fumigant was desorbed from insects after treatment and desorption was greater in those exposed for the shorter period. Statistical analysis on the three major variables which contribute to toxicity, namely concentration, time and fumigant uptake, showed that, for purposes of calculation, only the two factors, concentration and time, need to be considered; inclusion of data on uptake into the model did not provide appreciable contribution to explain the observed mortalities beyond that already given by concentration and time. A model which includes concentration, time and interaction between the two was found to describe the dosage-response relationship better than concentration and time alone.