Probing the topological surface states in superconducting Sn4Au single crystal: a magneto transport study.

Materials exhibiting bulk superconductivity along with magnetoresistance (MR) in their normal state have emerged as suitable candidates for topological superconductivity. In this article, we report a flux free method to synthesize single crystal of topological superconductor candidate Sn4Au. The phase purity and single crystalline nature are confirmed through various characterizations viz. x-ray diffraction, field emission scanning electron microscopy, selected area electron diffraction, and transmission electron microscopy. Chemical states of the constituent element viz. Sn and Au are analysed through x-ray photoelectron spectroscopy. Superconductivity in synthesized Sn4Au single crystal is evident formρ-Tplot, for which the critical field (Hc) is determined throughρ-Hplot at 2 K i.e. just below critical temperatureTc. A positive MR is observed inρ-Hmeasurements at different temperatures aboveTc, viz. at 3 K, 5 K, 10 K and 20 K. Further, the magnetoconductivity (MC) is analysed by using Hikami-Larkin-Nagaoka formalism, which signifies the presence of weak antilocalization (WAL) effect in Sn4Au. Angle dependent magneto-transport measurement has been performed to detect the origin of observed WAL effect in Sn4Au single crystal. Normalized MC vsHcosθplot shows presence of topological surface states in the studied system. It is evident that Sn4Au is a 2.6 K topological superconductor.

Traditional Knowledge to Contemporary Medication in the Treatment of Infectious Disease Dengue: A Review.

Dengue has become a worldwide affliction despite incessant efforts to search for a cure for this long-lived disease. Optimistic consequences for dengue vaccine are implausible as the efficiency is tied to previous dengue virus (DENV) exposure and a very high cost is required for large-scale production of vaccine. Medicinal plants are idyllic substitutes to fight DENV infection since they constitute important components of traditional medicine and show antiviral properties, although the mechanism behind the action of bioactive compounds to obstruct viral replication is less explored and yet to be discovered. This review includes the existing traditional knowledge on how DENV infects and multiplies in the host cells, conscripting different medicinal plants that obtained bioactive compounds with anti-dengue properties, and the probable mechanism on how bioactive compounds modulate the host immune system during DENV infection. Moreover, different plant species having such bioactive compounds reported for anti-DENV efficiency should be validated scientifically via different in vitro and in vivo studies.

Detailed magneto heat capacity analysis of SnAs topological superconductor.

In this article, we report magneto heat capacity analysis of superconducting SnAs. Magneto heat capacity analysis of superconductors is an important tool to determine bulk superconductivity as well as the pairing mechanism of Cooper pairs. SnAs crystal is characterized through x-ray diffraction and x-ray photoelectron spectroscopy. Magneto transport measurements of studied SnAs superconductor evidenced presence of superconductivity at around 4 K, which persists up to an applied field of 250 Oe. The bulk nature of superconductivity is determined through AC susceptibility (χ) along with the heat capacity measurements. Magneto heat capacity measurements show SnAs to be a fully gapped s wave superconductor. This finding is well supported by calculated physical parameters likeα(3.36),λe-ph(0.70) and ΔCel/γTc(1.41). Calculation of residual Sommerfeld coefficient (γres) at different fields, confirms node-less superconductivity in SnAs.

Green Approach: ''A Forwarding Step for Curing Leishmaniasis-A Neglected Tropical Disease''.

The present review focuses on a dreaded vector-mediated leishmaniasis, with the existing therapeutic approaches including a variety of drugs along with their limitations, the treatment with natural compounds, and different types of metal/metal oxide nanoparticles (NPs). As evidenced, various metallic NPs, comprising silver, silver oxide, gold, zinc oxide, titanium, lead oxide, etc., played a curative role to treat leishmaniasis, are also presented. Keeping in view the advance success of vaccines against the prevalent dreaded diseases in the past and the present scenario, efforts are also being made to develop vaccines based on these NP formulations.

A critical study of the manuscripts of Paryaya Muktavali available at Orissa.

Though the Nidana book of Madhavakara has been very popular among Ayurvedic fraternity his other deeds on Dravyaguna, Cikitsa etc. could not come to lime light due to lack of sufficient number of manuscripts for comparison and editing. One such text is Paryaya Muktavali, manuscripts of which are plentily available in the State of Orissa. This modified text redacted by Hari Charana Sena, is a bright example of scribal error and missing of verses which occur during repeated scribe in palm leaf manuscript. This is a lexicon of drugs, which is prime necessity of Dravyaguna and Rasasastra. Publication of such text will be an addition to the treasure of Ayurvedic texts.

Selective imaging of biofilms in porous media by NMR relaxation.

Nuclear magnetic resonance imaging (NMRI) techniques were employed to identify and selectively image biological films (biofilm) growing in aqueous systems. Biofilms are shown to affect both the longitudinal (T1) and transverse (T2) NMR relaxation time values of proximal water hydrogens. Results are shown for biofilm growth experiments performed in a transparent parallel-plate reactor. A comparison of biofilm distributions by both NMR and optical imaging yielded general agreement for both an open-flow system and an idealized porous system (the reactor without and with packed glass beads, respectively). The selective imaging of biofilm by relaxation NMRI is dependent upon the resolution of relaxation times for the fluid phases, dynamic range, and signal-to-noise ratio. For open-flow systems, the use of a rapid and quantitative T2-sorted NMRI technique was preferred. For porous systems where T2 values are generally more similar, a T1-weighted technique was preferred.

Evaluating the interaction of bacteria with biomaterials using atomic force microscopy.

Bacterial infection of biomaterials represents one of the most important reasons for the failure of transdermal or implanted medical devices. The first and least understood step in biomaterial-associated infections is the initial interaction between bacteria and a surface. This initial interaction can be either attractive or repulsive depending on the physiochemical nature of the biological and synthetic surfaces, as well as the properties of the interstitial fluid. We have shown that atomic force microscopy (AFM) can be employed as an exquisitely sensitive and versatile tool for quantifying the interaction between bacteria and surfaces in physiological solutions. The forces of interaction between an AFM cantilever tip and a uniform lawn of bacteria immobilized on glass were determined. By comparing the interactions of cantilever tips with lawns of isogenic E. coli strains carrying genetic lesions that alter their cell surface composition, it was possible to evaluate the effect of macromolecules such as lipopolysaccharide and capsular polysaccharide on the adhesion process. Mutations that result in the synthesis of truncated lipopolysaccharide or in the overproduction of the negatively charged capsular polysaccharide colanic acid render the interaction of the bacteria with the AFM tip unfavorable due to increased electrostatic repulsion. Furthermore, AFM could be used to evaluate the adhesion of bacteria onto commercially relevant biomaterials. In one approach, micron-size polystyrene beads were attached to AFM tips which were then used to measure forces. Unfortunately, this approach is limited by the meager number of materials manufactured as beads of a size suitable for AFM measurements. As an alternative approach, AFM cantilever tips were coated with a confluent layer of bacteria and used to probe planar surfaces. In this configuration, AFM could be employed to measure the force of interaction between virtually any bacterium and surface of interest.

Molecular determinants of bacterial adhesion monitored by atomic force microscopy.

Bacterial adhesion and the subsequent formation of biofilm are major concerns in biotechnology and medicine. The initial step in bacterial adhesion is the interaction of cells with a surface, a process governed by long-range forces, primarily van der Waals and electrostatic interactions. The precise manner in which the force of interaction is affected by cell surface components and by the physiochemical properties of materials is not well understood. Here, we show that atomic force microscopy can be used to analyze the initial events in bacterial adhesion with unprecedented resolution. Interactions between the cantilever tip and confluent monolayers of isogenic strains of Escherichia coli mutants exhibiting subtle differences in cell surface composition were measured. It was shown that the adhesion force is affected by the length of core lipopolysaccharide molecules on the E. coli cell surface and by the production of the capsular polysaccharide, colanic acid. Furthermore, by modifying the atomic force microscope tip we developed a method for determining whether bacteria are attracted or repelled by virtually any biomaterial of interest. This information will be critical for the design of materials that are resistant to bacterial adhesion.

Transport of bacteria in porous media: I. An experimental investigation.

The convective transport of concentrated suspension of bacteria in porous media is of interest for several processes such as microbial enhanced oil recovery and in situ bioremediation. The parameters which affect the transport of the bacterium Bacillus licheniformis JF-2, a candidate microorganism for microbial enhanced oil recovery, were investigated experimentally in sandpacks. Bacteria retention and permeability reduction occurred primarily in the first few centimeters upon entering the porous medium. In downstream sections of the sandpack, the permeability reduction was low, even in cases in which high cell concentrations (10(8) cfu/mL) were detected in the effluent. The effect of (i) addition of a dispersant, (ii) linear velocity of injection, (iii) cell concentration, (iv) salinity (v) temperature, and (vi) the presence of a residual oleic phase were determined experimentally. A lower reduction in permeability and a higher effluent bacterial concentration were obtained in the presence of dispersant, high injection velocities, low salinities, and at a higher temperature. Macroscopic measurements at different linear velocities and in the presence or absence of dispersants suggest that the formation of reversible microaggregates and multiparticle hydrodynamic exclusion may be the primary mechanisms for bacterial retention and permeability reduction. (c) 1994 John Wiley & Sons, Inc.

Transport of bacteria in porous media: II. A model for convective Transport and growth.

A model is presented for the coupled processes of bacterial growth and convective transport of bacteria has been modeled using a fractional flow approach. The various mechanisms of bacteria retention can be incorporated into the model through selection of an appropriate shape of the fractional flow curve. Permeability reduction due to pore plugging by bacteria was simulated using the effective medium theory. In porous media, the rates of transport and growth of bacteria, the generation of metabolic products, and the consumption of nutrients are strongly coupled processes. Consequently, the set of governing conservation equations form a set of coupled, nonlinear partial differential equations that were solved numerically. Reasonably good agreement between the model and experimental data has been obtained indicating that the physical processes incorporated in the model are adequate. The model has been used to predict the in situ transport and growth of bacteria, nutrient consumption, and metabolite production. It can be particularly useful in simulating laboratory experiments and in scaling microbial-enhanced oil recovery or bioremediation processes to the field. (c) 1994 John Wiley & Sons, Inc.

Structural and immunological characterization of a biosurfactant produced by Bacillus licheniformis JF-2.

Bacillus licheniformis JF-2 produces a very active biosurfactant under both aerobic and anaerobic conditions. We purified the surface-active compound to homogeneity by reverse-phase C18 high-performance liquid chromatography and showed that it is a lipopeptide with a molecular weight of 1,035. Amino acid analysis, fast atom mass and infrared spectroscopy, and, finally, 1H, 13C, and two-dimensional nuclear magnetic resonance demonstrated that the biosurfactant consists of a heterogeneous C15 fatty acid tail linked to a peptide moiety very similar to that of surfactin, a lipopeptide produced by Bacillus subtilis. Polyclonal antibodies were raised against surfactin and shown to exhibit identical reactivity towards purified JF-2 lipopeptide in competition enzyme-linked immunosorbent assays, thus providing further evidence for the structural similarity of these two compounds. Under optimal conditions, the B. licheniformis JF-2 biosurfactant exhibits a critical micelle concentration of 10 mg/liter and reduces the interfacial tension against decane to 6 x 10(-3) dyne/cm, which is one of the lowest interfacial tensions ever reported for a microbial surfactant.

Herbert screw: results of a single-centre trial.

We report the results of a single-centre trial of the Herbert screw in the treatment of acute fractures, fracture-dislocations and non-unions of the carpal scaphoid. In the trial, 22 patients were studied with a maximum follow-up of 2.5 years. Of the patients, 84 per cent had minimal or no pain, and 94 per cent were happy with their result or significantly improved. There was an average loss of 34 per cent of radial deviation of the wrist and of 10 per cent in cylinder grip strength. On radiographic examination, 86 per cent achieved satisfactory union. However, only 73 per cent of type D2 fractures united. Overall, the subjective and objective clinical results achieved were more satisfactory than the radiographic results would suggest.

Surface-active compounds from microorganisms.

Microbial surfactants are a structurally diverse group of compounds consisting of hydrophilic and hydrophobic domains and which partition preferentially at interfaces. Biosurfactants are of increasing interest commercially as substitutes for synthetic surfactants particularly for environmental applications. This article discusses recent progress in the genetic and biochemical analysis of biosurfactant synthesis as well as the current status of fermentation technologies.

Immediate effect of tobacco chewing in the form of 'paan' on certain cardio-respiratory parameters.

Immediate effect of tobacco in the form of chewing was evaluated in 40 healthy males (mean age 26.27 yrs.) not habituated to tobacco, who were given paan containing 200 mg of tobacco to chew (group T). Heart rate (HR), blood pressure (BP), forced vital capacity (FVC), FEV1 and peak expiratory flow rate (PEFR) were measured twice for each subject, once before chewing and again immediately after completion of chewing. Another 24 age and sex matched controls (group C) were given paan without tobacco to chew and cardiorespiratory parameters were recorded as for group T subjects. Electrocardiography was recorded in 10 group T and 10 group C subjects. Effect of tobacco chewing was also evaluated in 10 habitual tobacco chewers. Results showed statistically significant increments in HR and BP as well as a decline in T wave amplitude in ECG following tobacco chewing (group T subjects). The changes in HR and BP lasted for 15-30 mins, as observed in 10 of group T subjects. The FVC, FEV1 and PEFR showed marginal, though non-significant, increments after tobacco chewing. No significant difference in the cardiorespiratory responses to tobacco chewing could be seen between habitual and nonhabitual (group T) tobacco chewers. The changes in cardiovascular and respiratory parameters following paan (without tobacco) chewing in the control subjects were negligible and nonsignificant.

FEF200-1200, FEF25-75% and FEF75-85% in non-smokers of either sex and in male smokers residing at an altitude of 2150 M above MSL in Himachal Pradesh.

Forced expiratory flow (FEF) rates were determined for 170 (130 males and 40 females) healthy adults of Himachal Pradesh in the age group of 19-26 years for males and 19-22 years for females. The subjects had been staying at an altitude of 2150 M above mean sea level (MSL) for at least three years prior to the conduct of the study. FEF200-1200, FEF25-75% and FEF75-85% were found to be high as compared to those reported from most other parts of the country. The results were found comparable with those reported from certain populations in U.S.A. Further, the flow rates of the non-smoker males were compared with those of the male smokers. FEF75-85% in smokers was significantly less than that of non-smokers, whereas the differences in FEF200-1200 and FEF25-75% were found to be nonsignificant.

Efficacy of metronidazole in dracunculiasis. A clinical trial.

In a clinical trial of metronidazole for dracunculiasis (75 cases), the drug was effective in giving symptomatic relief but had no preventive or vermicidal action. It was well tolerated. No difference was observed in the results of two dose schedules (200 mg or 400 mg three times daily for 10 days).