An efficient numerical approach for solving a general class of nonlinear singular boundary value problems

Journal of Mathematical Chemistry - This paper is concerned with the development of a collocation method based on the Bessel polynomials for numerical solution of a general class of nonlinear...     

Activities of Hydrolases and Oxidases as Influenced by the Application of Monocrotophos in Sandy Loam Soil of Rajasthan

Continuous and repeated use of pesticides affects soil microbial flora and fauna and hence indirectly affects the activity of diverse microbial enzymes present within it. The present study investigates the interaction effect of different concentrations of monocrotophos on diverse hydrolases and oxidases, viz., protease, alkaline phosphatase, acid phosphatase, cellulase, amylase, invertase, arginine deaminase, and dehydrogenase, present in sandy loam soil of Rajasthan under in vitro conditions for 30 days. Soil sample was inoculated with three different concentrations of monocrotophos, viz., 50, 100, and 150 μg kg^-1, and incubated in dark at room temperature. At regular interval of 5 days, sample was withdrawn and enzyme activity was calculated and compared with that of control. Application of various concentrations of monocrotophos enhanced the activity of diverse enzymes present in soil. Therefore, the study revealed synergistic or additive effect of monocrotophos on all the tested microbial enzyme entities. Increasing concentration of the pesticide, however, poses an antagonistic interaction on the increment of different enzymes activities. Therefore, it can be concluded from the study that monocrotophos impose a positive effect at low concentration of pesticide, whereas high concentration poses negative effect on the activity of different enzymes present in soil.     

Recent Advances in the Applications of Ionic Liquids in Protein Stability and Activity: A Review

Room temperatures ionic liquids are considered as miraculous solvents for biological system. Due to their inimitable properties and large variety of applications, they have been widely used in enzyme catalysis and protein stability and separation. The related information present in the current review is helpful to the researchers working in the field of biotechnology and biochemistry to design or choose an ionic liquid that can serve as a noble and selective solvent for any particular enzymatic reaction, protein preservation and other protein based applications. We have extensively analyzed the methods used for studying the protein–IL interaction which is useful in providing information about structural and conformational dynamics of protein. This can be helpful to develop and understanding about the effect of ionic liquids on stability and activity of proteins. In addition, the affect of physico-chemical properties of ionic liquids, viz. hydrogen bond capacity and hydrophobicity on protein stability are discussed.     

Morphological,mechanical, and in vitro cytocompatibility analysis of poly(vinyl alcohol)–silica glass hybrid scaffolds reinforced with cellulose nanocrystals

Cellulose nanocrystal-reinforced poly(vinyl alcohol)/silica glass hybrid scaffolds were fabricated using the freeze-drying method. In this study, we develop molecular-level-based hybrid scaffolds with possible bioactivity behavior by adding silica sol–gel. The results showed a highly porous structure and a significant improvement in mechanical performance (stiffness) of hybrid scaffolds with an increased content of cellulose nanocrystals followed by the addition of silica-based bioactive glass. In vitro cell study with MC3T3-E1 cells on hybrid scaffolds for 1 and 3 days revealed good cell adhesion and growth. Thus, the obtained hybrid scaffold may be a competitive candidate for bone tissue engineering applications.     

Palladium-catalyzed regioselective synthesis of benzosultams from functionalized ynamides and benzotriazoles/tetrazoles

Palladium-catalyzed highly regioselective synthesis of benzotriazole appended benzosultams by the tandem-cyclization of functionalized ynamides with benzotriazoles has been accomplished. This transformation involves the formation of both CN and CC bonds in a single step. Donor solvents appear to enhance the yields of the products. The methodology is also applicable for the generation of triazole/tetrazole appended benzosultams.     

Detection of bacterial quorum sensing <Emphasis Type="Italic">N</Emphasis>-acyl homoserine lactones in clinical samples

Bacteria communicate among themselves using certain chemical signaling molecules. These signaling molecules generally are N-acyl homoserine lactones (AHLs) in Gram-negative bacteria and oligopeptides in Gram-positive bacteria. In addition, both Gram-positive and Gram-negative bacteria produce a family of signaling molecules known as autoinducer-2 that they employ for their communications. Bacteria coordinate their behavior by releasing and responding to the chemical signaling molecules present in proportion to their population density. This phenomenon is known as quorum sensing. The role of bacteria in the pathogenesis of several diseases, including gastrointestinal (GI) disorders, is well established. Moreover, rather recently bacterial quorum sensing has been implicated in the onset of bacterial pathogenicity. Thus, we hypothesized that the signaling molecules involved in bacterial communication may serve as potential biomarkers for the diagnosis and management of several bacteria-related diseases. For that, we previously developed a method based on genetically engineered whole-cell sensing systems for the rapid, sensitive, cost-effective and quantitative detection of AHLs in biological samples, such as saliva and stool, from both healthy and diseased individuals with GI disorders. Although various analytical methods, based on physical-chemical techniques and bacterial whole-cell biosensors, have been developed for the detection of AHLs in the supernatants of bacterial cultures, only a few of them have been applied to AHL monitoring in real samples. In this paper, we report work performed in our laboratory and review that from others that describes the detection of AHLs in biological, clinical samples, and report some of our recent experimental results.     

Indole-based distinctive chemosensors for ‘naked-eye’ detection of CN and HSO4−, associated with hydrogen-bonded complex and their DFT study

Colorimetric detection of anions (HSO₄^? and CN^?) was achieved via analyte triggered colour changing of the dipodal and tripodal sensors in CH₃CN–H₂O (1:1). The sensors exhibited very sharp visual colour changes and fluorescence quenching–enhancing effect upon addition of the HSO₄^? and CN^?. The large downfield shift of the NH proton signals in ¹H-NMR complexation studies and quantum chemical DFT calculations proved the formation of hydrogen-bonded complexes where no proton transfer mechanism was found.     

Antimicrobial Surgical Sutures: Recent Developments and Strategies

Surgical sutures are probably the most widely used medical devices in healthcare applications for wound closure. During their application, sutures may be exposed to microorganisms present in the environment leading to bacterial biofilm formation, and thereon to surgical site infections. The physicochemical characteristics of the polymeric substrate play a major role in directing the behavior of the suture in a biological milieu. In such a context, it is necessary to develop sutures which actively repel and inhibit bacterial adherence and colonization on their surfaces. Drug eluting sutures have been proposed as a solution to this dilemma. Currently, bioactive agents (natural or synthetic) are being incorporated in polymeric materials via various methods including blending and compounding, surface functionalization and conjugation, and coating to render antimicrobial surgical sutures. However, each of these methods has its own pros and cons. Depending upon the nature of the substrate, an appropriate processing technique has to be chosen. In this article, we review the recent state-of-the-art developments and strategies in antimicrobial surgical suture fabrication. The efficacy and mechanism of these sutures in controlling infection is critically analyzed. However, such bioactive agent incorporated sutures have to be tested in clinically randomized trials to accurately gauze their applicability in a surgical setting. Presently, very few antimicrobial surgical sutures are available commercially. Therefore, there is a great scope for market development in this area.     

Photochemical C–N bond forming reactions for the synthesis of five-membered fused N-heterocycles

Abstract

Few conversions cannot take place with ground-state reactions even with the help of a catalyst, therefore they are made to occur under photochemical conditions. The transfer of electrons took place even with the photochemical excitement of one molecule where redox reaction cannot occur at the ground state. The ground-state reactions resulted in the formation of side products. The substrates did not require any sort of chemical activation for C–N bond construction in the course of photochemical reactions. The source of energy; light has always been the interest of researchers in order to induce chemical reactions ever since the starting of scientific chemistry. The present review encloses the chemistry of photochemical transformations with a focus on their synthetic uses. The organic photochemical reactions prevent the polluting or harmful reagents thus, provides a possibility for sustainable procedures as well as green chemistry. This review article displays the formation of numerous of five-membered fused nitrogen-heterocyclic compounds.