15,997 research outputs found

    A newly discovered population of the critically endangered false limpet Siphonaria compressa Allanson, 1958 (Pulmonata: Siphonariidae), with observations on its reproductive biology

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    The endangered false limpet, Siphonaria compressa, originally described by Allanson in 1958 from Langebaan Lagoon, Saldanha, has been found living in intertidal eelgrass meadows in the embayment of the Knysna River estuary at Bollard Bay, Leisure Isle, Knysna, South Africa. This represents only the second known site of occurrence of the species. Although classified by the IUCN as critically endangered, the Knysna population is viable.Acrobat Distiller 6.0 (Windows

    BCG: Do we have an alternative?

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    Vaccination is generally used as a form of immunoprophylaxis, so that administration of the vaccine even a long. time before exposure to the wild-type infectious organism should afford protection. Since effector T and B cells are short-lived, a prime requisite for a vaccine is to generate immunological memory.1 In the case organisms such as mycobacteria which are obligate intracellular pathogens and which elicit granulomatous tissue reactions, artificial immunisation with live bacteria is required to induce protection.2,3 The only existing vaccine against tuberculosis is the BCG (Bacille Calmette - Guerin), an attenuated strain of M.bovis and it is mandatory or officially recommended in 182 countries or territories. Under the Expanded Programme on Immuisation (EPT) started by the Government of India in 1978, BCG is recommended to be given to all infants 3-9 months after birth.

    Bactericidal action of pulsed exposure to rifampicin, ethambutol, isoniazid & pyrazinamide on Mycobacterium tuberculosis in vitro

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    The bactericidal action of pulsed exposure to rifampicin (R), ethambutol (Emb), isoniazid (I) and pyrazinamide (Z) togcthcr on alternate days (REmbIZ) and as REmb and IZ separately on alternate days (REmb/IZ) on M.tuberculosis H37Rv, two isolates of M.tuberculosis sensitive to these drugs, as well as four isolates resistant to one or more drugs, was studied using an in vitro method. The experimental duration was 6 days. REmbIZ and REmb/IZ appeared to have equally good bactericidal action on M.tuberculosis strains in the in vitro system. The results suggest that splitting REmbIZ into REmb and IZ on alternate days in short course chemotherapy regimens for tuberculosis may not affect the bactericidal action of the regimens

    Protective response in guineapigs exposed to Mycobacterium avium intracellulare/ M. scrofulaceum, BCG & south Indian isolates of M. tuberculosis

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    The protective immunity resulting from exposure to nontuberculous mycobacteria (NTM), BCG and virulent mycobacteria in different sequences was studied in the guineapig model employing strains prevalent in the south Indian BCG trial area and time kinetics to observe the immuno-modulation. The findings suggest that during the early course of challenge infection in guineapigs there was no interference with the immunity due to BCG, by prior exposure to NTM. In the animals sensitised with M. avium intracellulare before immunisation, the challenge infection was localised and confined to the site of inoculation, and only a few organisms reached the spleen.. However, at the later stages of the infection, as seen by the spleen viable counts at 12 wk, it appeared that the barrier at the localised site of infection may not be intact in the animals with prior exposure to NTM, and a few organisms disseminate to the spleen

    Gallium Arsenide preparation and QE Lifetime Studies using the ALICE Photocathode Preparation Facility

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    In recent years, Gallium Arsenide (GaAs) type photocathodes have become widely used as electron sources in modern Energy Recovery Linac based light sources such as the Accelerators and Lasers in Combined Experiments (ALICE) at Daresbury Laboratory and as polarised electron source for the proposed International Linear Collider (ILC). Once activated to a Low Electron Affinity (LEA) state and illuminated by a laser, these materials can be used as a high-brightness source of both polarised and un-polarised electrons. This paper presents an effective multi-stage preparation procedure including heat cleaning, atomic hydrogen cleaning and the activation process for a GaAs photocathode. The stability of quantum efficiency (QE) and lifetime of activated to LEA state GaAs photocathode have been studied in the ALICE load-lock photocathode preparation facility which has a base pressure in the order of 10^-11 mbar. These studies are supported by further experimental evidence from surface science techniques such as X-ray Photoelectron Spectroscopy (XPS) to demonstrate the processes at the atomic level.Comment: Presented at First International Particle Accelerator Conference, IPAC'10, Kyoto, Japan, from 23 to 28 May 201

    Observations on the cultivation of M.leprae and M. tuberculosis in medium V and V1

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    Skin scrapings from five different active sites were collected from 14 leprosy patients and inoculated into medium V. Shin scrapings from three leprosy patients were inoculated into medium V 1. All the cultures were incubated at 8-10°C. M. tuberculosis H37Rv, pretreatment isoloates and streptomycin resistant strains were inoculated into medium V, with and without antibiotics, and incubated at 8-10°C as well as 37°C. Smears were made from the M. leprae and M. tuberculosis cultures at 0 hours and at different time points. The number of bacilli in the smears were counted. There was no increase in the number of M. leprae or M. tuberculosis in any of the cultures

    Gallium Arsenide solar cell radiation damage experiment

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    Gallium arsenide (GaAs) solar cells for space applications from three different manufactures were irradiated with 10 MeV protons or 1 MeV electrons. The electrical performance of the cells was measured at several fluence levels and compared. Silicon cells were included for reference and comparison. All the GaAs cell types performed similarly throughout the testing and showed a 36 to 56 percent power areal density advantage over the silicon cells. Thinner (8-mil versus 12-mil) GaAs cells provide a significant weight reduction. The use of germanium (Ge) substrates to improve mechanical integrity can be implemented with little impact on end of life performance in a radiation environment

    The overlap lattice Dirac operator and dynamical fermions

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    I show how to avoid a two level nested conjugate gradient procedure in the context of Hybrid Monte Carlo with the overlap fermionic action. The resulting procedure is quite similar to Hybrid Monte Carlo with domain wall fermions, but is more flexible and therefore has some potential worth exploring.Comment: Further expanded version. 12 pages, plain Te

    In vitro experiments with centella asiatics - investigation to elucidate the effect of an indigenously prepared powder of this plant on acid fastness and viability of M. tuberculosis

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    Tk herb Centella asiatica (Linn.).jound throughout India. is acclaimed 'to have medicinal properties and has been used in leprosy patients from very early times. It is considered that the active compound of this herb, called JlSiaticoside. probably acts on the waxy covering of M.leprae. The in vitro effect of an indigenously produced dry powder of Centella asiatica (CA) on the acidIJSt1Iess and viability of M.tuberculosis was investigated in the present study. Titt results indicate that CA may not have any direct action on the acidjastness or viabilty of M.tuberculosis H37Rv in vitro. Further studies using purified asiaticoside ofthe plant or in vivo studies are required
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