828 research outputs found

    Modeling charge transport in Swept Charge Devices for X-ray spectroscopy

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    We present the formulation of an analytical model which simulates charge transport in Swept Charge Devices (SCDs) to understand the nature of the spectral redistribution function (SRF). We attempt to construct the energy-dependent and position dependent SRF by modeling the photon interaction, charge cloud generation and various loss mechanisms viz., recombination, partial charge collection and split events. The model will help in optimizing event selection, maximize event recovery and improve spectral modeling for Chandrayaan-2 (slated for launch in 2014). A proto-type physical model is developed and the algorithm along with its results are discussed in this paper.Comment: 9 pages, 7 figures, Proc. SPIE 8453, High Energy, Optical, and Infrared Detectors for Astronomy

    An improved method for the synthesis of cyclopropyl ketoesters

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    A simple and versatile method for the synthesis of cyclopropyl ketoesters starting from chalcones and ethyl cyanoacetate in benzene using sodium powder as base is described

    Fibre optic sensor to detect heavy metal pollutants in water environments.

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    Heavy metal ion pollution emerges as a potential threat to humankind and the ecosystem due to their increased spreading into the environment. Detection of highly toxic heavy metal ions requires rapid, simple, sensitive and selective detection methods in water environments. Optical fibre sensors facilitate the remote, continuous and in-situ detection due to their inherent properties. Herein, we report a fibre optic sensor based on evanescent wave absorption to detect heavy metal ions in water environments. Fibre optic sensor has been developed by coating dithizone on the surface of an optical fibre. Selectivity of the mercury, copper and chromium ions using dithizone has been illustrated using spectroscopy based detection approach. Effect of pH on the sensor has been investigated. The possibility of simultaneous multi-ion detection has been investigated. Copper ions concentrations in water has been detected using the developed fibre optic sensor

    Value of dual testing for identifying tuberculous infection

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    Setting: A rural community in Chingleput district in Tamil Nadu state in south India. Objective: To determine the value of dual testing with PPD-S and PPD-B for identifying subjects with a tuberculous infection. Design: About 240,000 subjects in rural south India, all of whom were tested initially with PPD-S and PPD-B, were followed up for 15 years, mainly by total population survey once in every 212 years. The incidence of culture-positive tuberculosis was estimated using life-table technique. Results: Among 17,530 subjects with an intermediate reaction (8–11 mm) to PPD-S at intake, 285 with an induration to PPD-S exceeding the induration to PPD-B by at least 2 mm, had a significantly higher incidence of culture-positive tuberculosis than the remaining (154 and 93 per 100,000), and similarly 481 who had an induration of o10mm to PPD-B compared to those with X10mm (131 and 93 per 100,000). These subjects may be regarded as having a tuberculous infection. Infection with non-tuberculous mycobacteria conferred protection of about 30% against the development of tuberculosis over a 15-year period. Conclusion: In subjects with an intermediate reaction (8–11 mm) to PPD-S, dual testing with PPD-B enabled identification of those with a tuberculous infection. Most of the reactions were due to non-tuberculous mycobacteria

    Establishment of High-Efficiency Agrobacterium-Mediated Transformation of Callus Derived from \u3cem\u3eSehima nervosum\u3c/em\u3e, an Important Range Grass Species

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    Sehima nervosum is one of the important rangeland grass in India, It is commonly known as Saen grass in India, white grass in Australia, and has also been reported from the Central East Africa and Sudan. It is a good forage grass and maybe utilized for grazing as well as for hay preparation. It is a perennial grass, prefers hot and dry climate and survive even in limited rainfalls. As this natural grass is found inherently rich in precursors for several industrially important biomolecules, fractionation of these precursors seems to be a promising endeavour. Production of nutraceuticals (prebiotic xylo-oligosaccharides) from the lignocellulosic biomass of this grass is promising, as this grass does not compete with food crops, and is comparatively less expensive than conventional agricultural food-stocks. However, germplasm of this grass has narrow genetic variability. Being largely apomictic in reproduction, generation of variability through hybridization approaches have been limited. Utilization of biotechnological tools is one of the potential ways for introducing variability and transfer of desirable traits. The development of an efficient genetic transformation procedure for Sehima could facilitate physiological and molecular biology studies as well as the production of transgenic cultivars for higher productivity and quality. To the best of our knowledge there are no reports on in vitro callus induction, regeneration and transformation in Sehima. Herein, for the first time, efficient in vitro callus induction from mature seed explant and transformation efficiency in Sehima is reported. Here we standardized a reproducible, rapid and efficient Agrobacterium mediated transformation using Agrobacterium strain EHA105 harbouring binary vector pCAMBIA 1305

    The Role of Diet in the Treatment of Pulmonary Tuberculosis: An Evaluation in a Controlled Chemotherapy Study in Home and Sanatorium Patients in South India

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    Before the advent of antituberculosis chemotherapy, a diet rich in calories, proteins, fats, minerals and vitamins was generally considered to be an important, if not essential, factor in the treatment of tuberculosis. The introduction of specific antituberculosis drugs, however, has so radically altered the management of the disease that the role of diet has to be reconsidered in the light of the recent advances in treatment. An evaluation of the influence of diet in the treatment of pulmonary tuberculosis with isoniazid plus p-aminosalicylic acid was recently undertaken by the Tuberculosis Chemotherapy Centre, Madras, in the course of a controlled comparison of home and sanatorium chemotherapy for tuberculous patients from a poverty-stricken community in Madras City. Despite the fact that during the year of treatment the home patients subsisted on a markedly poorer diet, were physically more active and, on the average, gained less weight than the sanatorium patients, the overall response to treatment in the home series closely approached that in the sanatorium series, although there was a tendency for tubercle bacilli to disappear earlier in the latter. Direct evidence has been presented that none of the dietary factors studied (calories, carbohydrates, total and animal proteins, fats, minerals and vitamins) appears to influence the attainment of quiescent disease among tuberculous patients treated for one year with an effective combination of antimicrobial drugs, and that initial chemotherapy of patients at home can be successful even if the dietary intake is low throughout the period of treatment

    Trends and the pole tide in Indian tidegauge records

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    This paper studies tidegauge records of stations on the Indian coastline. An analysis of trends did not reveal a monotonie trend. Trends were seen for limited periods at only five of the eight stations on the Indian coast. A spectral analysis of annual records produced evidence of long period cycles with shorter cycles riding on them. The shorter cycles had a period of 5.0 years. The spectra of monthly records revealed evidence of a pole tide and an annual cycle. The amplitude of the pole tide was estimated to be around 7.5 mm. This was larger than the equilibrium tide. A spectral analysis of monthly rainfall at Bombay, a station on the Indian west coast, also showed a 13.9 month cycle and a (3,1,0) autoregressive model. But the coherence between monthly rainfall and relative sealevel fluctuations was low

    A novel system to obtain addresses of out-patients-assessent in routine clinic practice in Madras

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    A novel method of obtaining accurate home addresses from out-patients was introduced as a routine procedure in 6 chest clinics of Madras City, following highly satisfactory results under study conditions. In this method, the patient is given a card (the address card), and asked to get his exact address entered on it by any knowledgeable person of his choice such as a landlord or neighbour. An assessment of the system was undertaken after it had been in operation for about 8 months. A complete and legible address was available for 82 % of 3956 patients, the range in the 6 clinics being 74 % to 91 %. The main causes for failure were : not giving address card to patient (7 %), patient not reattending the clinic (6 %), and patient reattending but not returning the address card (3%). Corrective measures have now been introduced, and a re-assessment will be undertaken in due course
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