Elucidation of the molecular aspects of small molecule-RNA complexation is of prime importance for rational RNA targeted drug design strategies. Towards this, the interaction of the cytotoxic plant alkaloid sanguinarine to three double stranded ribonucleic acids, poly (A).poly(U), poly(I).poly(C) and poly(C).poly(G) was studied using various biophysical and thermodynamic techniques. Absorbance and fluorescence studies showed that the alkaloid bound cooperatively to these RNAs with binding affinities of the order 10(4) M(-1). Fluorescence quenching and hydrodynamic studies gave evidence for intercalation of sanguinarine to these RNA duplexes. Isothermal titration calorimetric studies revealed that the binding was characterized by negative enthalpy and positive entropy changes and the affinity constants derived were in agreement with the overall binding affinity values obtained from spectroscopic data. The binding of sanguinarine stabilized the melting of poly(A). poly(U) and poly(I).poly(C) and the binding data evaluated from the melting data were in agreement with that obtained from other techniques. The overall binding affinity of sanguinarine to these double stranded RNAs varied in the order, poly(A).poly(U) > poly(I).poly(C) >> poly(C).poly(G). The temperature dependence of the enthalpy changes afforded negative values of heat capacity changes for the binding of sanguinarine to poly(A).poly(U) and poly(I).poly(C), suggesting substantial hydrophobic contribution in the binding process. Further, enthalpy-entropy compensation phenomena was also seen in poly(A).poly(U) and poly(I).poly(C) systems that correlated to the strong binding involving a multiplicity of weak noncovalent interactions compared to the weak binding with poly(C).poly(G). These results further advance our understanding on the binding of small molecules that are specific binders to double stranded RNA sequences.

The focus of this study is to discover the use, purpose, importance and problems faced by the library and information professionals in Bangladesh in marketing through social media. For this study public universities (17), private universities (24) and special (5) libraries in Bangladesh were selected as a research sample. The findings of this paper showed that most of the libraries use Facebook and LinkedIn for marketing of library and information services. Most of the libraries use social media for marketing library product and services, for sharing library news and events, video conferencing, advertisement, and research purpose. An online version of the questionnaire was distributed in the respective libraries in Bangladesh. Library professionals also provided necessary suggestions and opinions about ways of enhancing library services through using social media.

Most clinical isolates of Acinetobacter baumannii, a nosocomial pathogen, are multidrug-resistant (MDR), fueling the search for alternative therapies. Bacteriophage-derived endolysins have potent antibacterial activities and are considered as alternatives to antibiotics against A. baumannii infection. Gram-negative bacteria possess outer lipid membrane that prevents direct contact between the endolysins and the cell wall. We hypothesized that the fusion of antimicrobial peptide (AMP) with endolysin could help to reduce bacterial endolysin resistance and increase antimicrobial activity by membrane permeability action. Accordingly, we fused cecropin A, a commonly used AMP, with the N-terminus of AbEndolysin, which enhances the bactericidal activity of the chimeric endolysin. The bactericidal activity of cecropin A-fused AbEndolysin increased by at least 2–8 fold for various MDR A. baumannii clinical isolates. The in vitro bactericidal activity results also showed higher bacterial lysis by the chimeric endolysin than that by the parental lysin. The engineered AbEndolysin (eAbEndolysin) showed synergistic effects with the beta-lactam antibiotics cefotaxime, ceftazidime, and aztreonam, and an additive effect with meropenem and imipenem. eAbEndolysin had no cytotoxic effect on A549 cell line and rescued mice (40% survival rate) from systemic A. baumannii infection. Together, these findings suggest the potential of lysin therapy and may prompt its use as an alternative to antibiotics.

PurposeThe main aim of this paper is to assess Dhaka University students' perceptions of ease‐of‐use and their satisfaction with University Library's online public access catalogue (DUL OPAC).Design/methodology/approachA survey questionnaire was developed and used to collect data on students' demographics, online catalogue use and their perceptions of ease‐of‐use and satisfaction with OPAC. In order to analyze the influence of students' demographic and individual characteristics on their perceptions and satisfaction, Mann‐Whitney and Kruskal‐Wallis tests were carried out.FindingsThe results showed that students are overwhelmingly satisfied with the DUL OPAC. Although there are some differences in students' perceptions of and satisfaction with the university OPAC, a formal task‐based usability testing and adopting a user‐centered design can ensure the usability of the OPAC in the future. The paper suggested some heuristic guidelines for designing interfaces for online catalogues.Originality/valueThis is the first time an effort has been made to assess students' perceptions of and satisfaction with a library OPAC in Bangladesh. The authors feel this study may encourage more such research on usability evaluation of OPACs in Bangladesh and beyond.

This paper investigates the impact of Krypton (Kr) seeding on plasma parameters in the D-module of GAMMA 10/PDX experimentally based on the calorimeter, Langmuir probe and high-speed camera measurements. The heat flux distribution along the V-shaped target plate reduces with the increasing Kr injection. The time behavior of ion flux shows that it decreases with the increase of Kr seeding. The electron temperature (T e ) reduces significantly due to Kr seeding into the D-module. The electron density shows a so-called roll-over phenomenon during Kr seeding. The heat and ion fluxes reduce with the increasing Kr seeding into the D-module. Two-dimensional images captured by the high-speed camera also show that the emission intensity significantly reduces inside the V-shaped target at the higher Kr injection. These outcomes represent the impact of Kr seeding for generating the detached plasma.

Gas fueling by supersonic molecular beam injection (SMBI) has been performed at the central-cell in GAMMA 10. The results of SMBI experiment with plenum pressure from 0.3 MPa to 2.0 MPa were obtained using a laval nozzle. The distribution of the emission intensity during SMBI was investigated by the 2-dimensional image captured by the fast camera as an index of the neutral transport. The experimental results indicates that the effect of the laval nozzle reduces the dispersion of injected hydrogen molecules in the peripheral region. In this paper, we also studied the line density at the central-cell (NLcc) and Hα emission intensity during SMBI. Comparison between SMBI and conventional gas puffing is also discussed from the view point of the fueling efficiency.

A catalyst-free green methodology for the synthesis of pharmacologically important spirooxindole derivatives has been developed by a three-component domino reaction between isatin, various amino compounds, and 1,3-dicarbonyl or 3-phenylisoxazolone compounds in ethyl L-lactate medium at room temperature. This new efficient synthetic method facilitated the formation of a wide range of biologically significant spirooxindole derivatives (including 17 new spirooxindoles) under very mild conditions. The cytotoxic activity of one of the isoxazole-fused spirooxindoles was evaluated in MDA-MB 468 breast cancer cell line. It was found that cell survivability decreases with increasing concentration of the selected compound in MDA-MB 468 breast cancer cells.

No abstract