752 research outputs found

    The motion of bubbles inside drops in containerless processing

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    A theoretical model of thermocapillary bubble motion inside a drop, located in a space laboratory, due to an arbitrary axisymmetric temperature distribution on the drop surface was constructed. Typical results for the stream function and temperature fields as well as the migration velocity of the bubble were obtained in the quasistatic limit. The motion of bubbles in a rotating body of liquid was studied experimentally, and an approximate theoretical model was developed. Comparison of the experimental observations of the bubble trajectories and centering times with theoretical predictions lends qualified support to the theory

    BIOGENIC SYNTHESIS SILVER NANOPARTICLES USING PELTOPHORUM PTEROCARPUM LEAF EXTRACTS AND ITS ANTIMICROBIAL EFFICACY AGAINST SELECTIVE PATHOGENS

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    Objective: The present study was aimed to screen silver nanoparticles (AgNPs) using different plant extracts and also to study their antimicrobial property against different human pathogens.Methods: Nine different plants, namely Parthenium hispidum, Vinga rose, Catheranthus roseus, Phyllanthus amarus, Azadirachta indica, Jatropa curcas, Tectona grandis, Ocimum sanctum, and Peltophorum pterocarpum were screened for the synthesis of AgNPs. The AgNPs were synthesized using leaf extracts and was well characterized using a UV-Visible spectrophotometer, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and zeta potential measurement. The AgNPs was tested for their antibacterial and antifungal efficacy using agar well diffusion method.Results: Among the nine different plant extracts screened, AgNPs synthesized using Peltophorum pterocarpum leaf extract showed good stability even after one month with maximum absorption spectra of 425 nm. The synthesized AgNPs was found to be spherical in shape with an average size ranging from 20 to 60 nm. The EDX spectrum reveals the presence of silver peaks and the XRD spectrum confirms the crystalline nature of AgNPs. A Maximum zone of inhibition of 18.04±0.74 was found when the synthesized AgNPs was tested against B. subtilis, and 12.34±0.31 against A. niger when the concentration was AgNPs was maintained at 100 µg/ml.Conclusion: The results of the present study conclude that the AgNPs synthesized using Peltophorum pterocarpum leaf extracts is found to be stable and possesses broad-spectrum antibacterial activity against different tested pathogens

    Awareness of farmers about social forestry programme - an analysis

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    A study was conducted to assess the awareness level of farmers on various components of Social forestry Programme, implemented by the Social Forestry Department in Ke rala State, India. It could be inferred/rom the study that the awareness level on /arm/oreslry lVas very high. On the other hand the awareness level on coastal area plantations and fodder plantations was relatively lesser. Variables such as education, material possession, media participation, contact with extension agency and economic motivation had a positive relationship with the awarelIess level of marginal farmers whereas variables like age, occupation, social participation and risk orientation had a negative influence on awareness. It was also observed that exceptfor education and risk orientation, all the other variables had a positive relationship with the awareness level of small farmers

    A percutaneous needle biopsy technique for sampling the supraclavicular brown adipose tissue depot of humans.

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    Brown adipose tissue (BAT) has been proposed as a potential target tissue against obesity and its related metabolic complications. Although the molecular and functional characteristics of BAT have been intensively studied in rodents, only a few studies have used human BAT specimens due to the difficulty of sampling human BAT deposits. We established a novel positron emission tomography and computed tomography-guided Bergström needle biopsy technique to acquire human BAT specimens from the supraclavicular area in human subjects. Forty-three biopsies were performed on 23 participants. The procedure was tolerated well by the majority of participants. No major complications were noted. Numbness (9.6%) and hematoma (2.3%) were the two minor complications noted, which fully resolved. Thus, the proposed biopsy technique can be considered safe with only minimal risk of adverse events. Adoption of the proposed method is expected to increase the sampling of the supraclavicular BAT depot for research purposes so as to augment the scientific knowledge of the biology of human BAT

    Studies on the proteinaceous gel secretion from the skin of the catfish, Arius maculatus (Thunberg, 1792)

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    The Catfish Arius maculatus (Thunberg, 1792) causes injury to the fisherman while handling the fish and it was proven that the skin mucus of the fish have several properties including the toxicity. In the present study, the biochemical property of the catfish skin mucus was characterized and it was found that the protein content of the soluble and insoluble fractions were 9.34 and 12.64 ìg/g, respectively. The total lipid was 0.005 ìg/g and the total carbohydrate was 0.08 ìg/g. Of the total 17 amino acids recorded, cysteine availability was very low; 0.01 and 0.02 mole % in the soluble and insoluble fractions, respectively. Leucine was available in high quantity (9.8 mole %) in the soluble fraction and aspartic acid (9.0 mole %) was high in the insoluble fraction. On SDS-PAGE analysis, seven and six bands with a distinct band at 35 KDa in the soluble and insoluble fractions, respectively, were observed. On haemolytic activity, lysis was observed by 50 ìg/ml of insoluble fraction and 25 ìg/ml of soluble fraction. Both soluble and insoluble fractions showed maximum and minimum activities against Escherichia coli and Pseudomonas aueruginosa, respectively

    Physical phenomena in containerless glass processing

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    Experiments were conducted on bubble migration in rotating liquid bodies contained in a sphere. Experiments were initiated on the migration of a drop in a slightly less dense continuous phase contained in a rotating sphere. A refined apparatus for the study of thermocapillar flow in a glass melt was built, and data were acquired on surface velocities in the melt. Similar data also were obtained from an ambient temperature fluid model. The data were analyzed and correlated with the aid of theory. Data were obtained on flow velocities in a pendant drop heated from above. The motion in this system was driven principally by thermocapillarity. An apparatus was designed for the study of volatilization from a glass melt

    Involvement of extension personnel in implementing social forestry programmes

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    In a country like India, where the population is high and resources are limited, social forestry is an instrument for rural development, particularly for the poor people. Thus social forestry is identified as a forestry of the people, by the people and for the people

    Enterocin from Enterococcus faecium isolated from mangrove environment

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    Enterococcus faecium isolated from mangrove environment produced enterocin and it showed broad inhibitory spectrum against gram positive and gram negative bacteria such as Lactobacillus plantarum, Enterococcus facealis, Listeria monocytogens and Salmonella paratyphii. The optimum production ofbacteriocin (2400 AU/ml) from E. faceium was obtained when the culture conditions were maintained at pH 6.0 and 35°C. Maximum yield was 40% in ion exchange chromatography. The molecular weight of the partially purified enterocin was estimated as 5 KDa by SDS PAGE electrophoresis

    Risk factors for admission and the role of respiratory syncytial virus-specific cytotoxic T-lymphocyte responses in children with acute bronchiolitis

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    Background. Risk factors for admission of children with acute bronchiolitis have remained controversial. Technological advances in the measurements of cytotoxic T-lymphocyte (CTL) activity, enable respiratory syncytial virus (RSV)-specific CTL activity to be studied in infants with bronchiolitis for the first time. We evaluated risk factors for admission of children with acute bronchiolitis and determined the role of CTL responses in those infected with RSV.Method. Children between 3 and 24 months of age presenting with bronchiolitis to the paediatric outpatient department at King Edward VIII Hospital, Durban, over a 1-year period were enrolled. Management included clinical evaluation, nasopharyngeal aspiration, standard treatment and hospitalisation if indicated. Secretions were tested with monoclonal antibodies for RSV and pooled respiratory viruses; shell vial cultures were also established. Permission was requested from parents of RSV-infected subjects for blood draws for specific cytotoxic T-cell assays and CD4/CD8 cells on admission and repeat CTL on day 7.Results. Viruses were identified in 55 of the 114 subjects studied (48.2%). RSV was seen in 41 cases (74.5%). Twenty three infants (20.2%) required admission. Risk factors associated with inpatient admissions on univariate analysis included younger mean age (7.6 months v. 10.1 months), overcrowding (p < 0.01) and indoor exposure to products of combustion of cooking fuels (p = 0.05). Only the former two were significant on multivariate analysis. RSV-specific CTL responses were obtained in 21 children (51.2%). Responses were either very weak (N = 7) or negative (N = 14) on day 0 and did not alter significantly on day 7. The mean CD4/CD8 ratios in this group were 2.27:1. The highest frequency of CTL was directed against the proteins 'M4/5/6', with counts ranging from 100 to 400 spot forming cells (sfc)/million.Conclusion. Measures to address risk factors identified in this study may decrease the need for hospitalisation from bronchiolitis. The lack of RSV-specific CTL responses in peripheral blood of immunocompetent RSV-infected children suggest an alternative method of induction of immunity or compartmentalisation of immune cells

    Solving the initial conditions problem for modified gravity theories

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    Modified gravity theories such as Einstein scalar Gauss Bonnet contain higher-derivative terms in the spacetime curvature in their action, which results in modifications to the Hamiltonian and momentum constraints of the theory. In principle, such modifications may affect the principal part of the operator in the resulting elliptic equations, and so further complicate the already highly nonlinear, coupled constraints that apply to the initial data in numerical relativity simulations of curved spacetimes. However, since these are effective field theories, we expect the additional curvature terms to be small, which motivates treating them simply as an additional source in the constraints, and iterating to find a solution to the full problem. In this work we implement and test a modification to the CTT/CTTK methods of solving the constraints for the case of the most general four derivative, parity invariant scalar-tensor theory, and show that solutions can be found in both asymptotically flat/black hole and periodic/cosmological spacetimes, even up to couplings of order unity in the theory. Such methods will allow for numerical investigations of a much broader class of initial data than has previously been possible in these theories, and should be straightforward to extend to similar models in the Horndeski class
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