940 research outputs found

    Dissociative electron attachment to formamide

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    Formamide (HCONH2) is the smallest molecule with a peptide bond and has recently been observed in the interstellar medium (ISM), suggesting that it may be ubiquitous in star-forming regions. There is therefore considerable interest in the mechanisms by which this molecule may form. One method is electron induced chemistry within the icy mantles on the surface of dust grains. In particular it has been recently shown that functional group dependence exists in electron attachment processes giving rise to site selective fragmentation of molecules at the C-H, O-H and N-H bonds at energies well beyond the threshold for the breaking of any of these bonds allowing novel forms of chemistry that have little or no activation barriers, such as are necessary in the ISM. In this poster we present the results of resent studies on dissociative electron attachment (DEA) to formamide DEA using an improved version of a Velocity Map Imaging (VMI) spectrometer comprised of a magnetically collimated and low energy pulsed electron gun, a Faraday cup (to measure the incident current), an effusive molecular beam, a pulsed field ion extraction, a time of flight analyzer and a two-dimensional position sensitive detector consisting of microchannel plate and a phosphor screen. The VMI spectrometer measures the kinetic energy and angular distribution of the fragment anions produced in the dissociative electron attachment process. The kinetic energy measurements provide information on the internal energies of the fragment anions and determine the dissociation limits of the parent negative ion resonant states responsible for the dissociative electron attachment process. The angular distribution measurements provide the information about the symmetry of these negative ion resonant states. We shall present the details, results and conclusions of these measurements during the conference

    PONDER - A Real time software backend for pulsar and IPS observations at the Ooty Radio Telescope

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    This paper describes a new real-time versatile backend, the Pulsar Ooty Radio Telescope New Digital Efficient Receiver (PONDER), which has been designed to operate along with the legacy analog system of the Ooty Radio Telescope (ORT). PONDER makes use of the current state of the art computing hardware, a Graphical Processing Unit (GPU) and sufficiently large disk storage to support high time resolution real-time data of pulsar observations, obtained by coherent dedispersion over a bandpass of 16 MHz. Four different modes for pulsar observations are implemented in PONDER to provide standard reduced data products, such as time-stamped integrated profiles and dedispersed time series, allowing faster avenues to scientific results for a variety of pulsar studies. Additionally, PONDER also supports general modes of interplanetary scintillation (IPS) measurements and very long baseline interferometry data recording. The IPS mode yields a single polarisation correlated time series of solar wind scintillation over a bandwidth of about four times larger (16 MHz) than that of the legacy system as well as its fluctuation spectrum with high temporal and frequency resolutions. The key point is that all the above modes operate in real time. This paper presents the design aspects of PONDER and outlines the design methodology for future similar backends. It also explains the principal operations of PONDER, illustrates its capabilities for a variety of pulsar and IPS observations and demonstrates its usefulness for a variety of astrophysical studies using the high sensitivity of the ORT.Comment: 25 pages, 14 figures, Accepted by Experimental Astronom

    Hepatoprotective potency of Lagenandra toxicaria and Ariopsis peltata against CCl4 induced liver fibrosis in Wistar rats

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    Lagenandra toxicaria (LT) and Ariopsis peltata (AP) belongs to the family Araceae. LT is being traditionally used to cure bilious symptoms and wound healing. AP leaves are edible and the rhizome has medicinal value. With such a wide range of medicinal applications, it's essential to scientifically authenticate traditional usage and find the plant's bioactive components. Here, we have examined the anti-inflammatory and hepatoprotective potency of these plant extracts. The in-vivo liver fibrosis was induced in Wistar male rats using CCl4 and was treated with various concentrations of the methanol and water extracts of the plant rhizomes. In the in-vitro anti-inflammatory assay, LT methanol extract showed 42 % protection at 600 mg/ml which is higher than the other extracts. Among the AP and LT extracts, the 600 mg/kg methanol extract of LT treated rats showed a decreased (p<0.05) serum alanine/aspartate aminotransferase and total bilirubin levels. The plant extract brought about an amelioration of CCl4 induced pathological effects and a significant reduction in the severity of inflammation, fatty metamorphosis, necrosis and liver fibrosis. Overall, the results suggest that LT rhizome could be effective in the treatment of liver fibrosis. It is possible that this is related to the presence of anti-inflammatory and antioxidant chemicals such as 9-octadecenamide, flavonoids and phenols in the extract

    Clinical Profile of Leptospirosis in North Chennai: A Study of 106 Cases

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    INTRODUCTION: Infectious disease is an important cause of morbidity and mortality in our country. Leptospirosis has been considered a rare zoonotic disease in India, with only sporadic cases recorded. Recently, however the disease was reported in Chennai during monsoon months in mini-epidemic proportions. In Chennai leptospirosis occurs in severe form causing jaundice and renal failure. It is usually reported during monsoon months. Recently diagnosis of leptospirosis has been simplified using modified Faine’s criteria. This criteria utilizes clinical, epidemiological and laboratory parameters for diagnosis. This criterion has been useful for diagnosis of milder forms of leptospirosis. This study has been undertaken to study the clinical features, epidemiological profile of leptospirosis in our hospital which caters to population in north Chennai. Leptospirosis has been frequently under diagnosed and under reported due to lack of awareness of disease and lack of appropriate diagnostic facilities. Combining clinical expertise & awareness with laboratory backup, increases the recognition of the disease. AIM OF THE STUDY: 1. To study the clinical features of mild & severe leptospirosis utilizing modified Faine’s criteria in North Chennai. 2. To evaluate the epidemiological risk factors in these patients. MATERIALS AND METHODS: Patients admitted to the medical wards of Govt.Stanley hospital with fever due to infectious disease of duration of more than 5 days who were positive by slide agglutination test were taken up for the study. Patients aged 15 -60 years were taken up for the study. The period of study was from May 2004 to December 2005. Diagnostic criteria: Leptospirosis was diagnosed utilizing Modified Faine’s criteria - Clinical, Epidemiological, Lab data (score >25). Exclusion criteria: Malaria, viral hepatitis, UTI, enteric fever, TB and pediatric cases were excluded from the study. RESULTS: A total of 106 patients diagnosed of leptospirosis were analyzed. There were 69 males & 37 females. The mean age was 31.2 years. The age/sex group data shows that maximum number of cases were seen in age group 21 to 30 years. The occupation of the patients in which maximum percentage of cases seen outdoor manual work of about 39.4% and in North Chennai areas surrounding the hospital has the maximum number of cases. contaminated environment & animal contact was about 95% & 94% respectively. Rainfall was seen in 50% of cases. Table -24 shows the seasonal distribution of cases. Cases occurred throughout the year with maximum number of cases during September to December. clinical features in which fever 100%, headache-95%, and myalgia- 90% with conjunctival suffusion about 18%. Hypotension and hypovolemia constituted about 26%. Anicteric presentation was about 82%. Table-26 shows the faine scoring 48 % of the cases had a score between 25-30 and another 45 % had score between 31- 35. renal function data, about 10.3% had renal failure (mean creatinine 3.5 mg%) and table 29 shows liver function data, about 17.8% had jaundice (mean Bilirubin 2.8 mg%). Table-30 shows the Hemogram details with total count, platelet and hemoglobin almost within normal range. All mild cases were treated with oral Doxycyline. Severely ill patients (organ dysfunction) treated with IV penicillin. 2 patients dialyzed. All patients recovered (mortality nil). SUMMARY: 1) A total of 106 patients with leptospirosis was analyzed, males-69, females - 37 & mean age was 31.2. 2) Out door manual workers were the group at highest risk to develop Leptospirosis. 3) Contaminated environment (95%), animal contact (94%) were important epidemiological factors. Rainfall was important risk factor in 50% of patients. 4) Most of the cases occurred between August to December. 5) Anicteric leptospirosis (82%) along with fever, headache, and myalgia were common clinical presentation. Conjunctival suffusion & Meningism was rare. 6) Jaundice occurred in 17.8% (Mean Bilirubin 2.8 mg %). 7) Renal failure occurred in 10.3% (mild 5.6%, moderate 1.8%, severe 2.8%), 2 patients were dialyzed. 8) All patients recovered , mortality- nil. 9) Modified Faine’s criteria was valuable for diagnosis of leptospirosis (especially anicteric). CONCLUSION: 1. Anicteric leptospirosis is the common presentation (82%) in north Chennai. 2. Lower incidence of jaundice and renal failure. 3. It also occurs in non-monsoon months. 4. Contaminated environment is an important risk factor/ outdoor manual workers are the vulnerable risk group. 5. Role of modified Faine’s criteria with single diagnostic test MSAT makes diagnosis easy. 6. Recommended that all fever patients be evaluated for leptospirosis

    Tuftsin-bearing liposomes as drug vehicles in the treatment of experimental aspergillosis

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    AbstractEncapsulation of amphotericin B in tuftsin-bearing liposomes greatly increased its efficacy in treatment of human aspergillosis in mice. Also, the drug efficacy was significantly increased by pretreating the animals with drug-free tuftsin-bearing liposomes. These results demonstrate that macrophage activation can considerably enhance the therapeutic efficacy of antifungal drugs, like amphotericin B

    Relative oral bioavailability of three formulations of vitamin D3: An open-label, three-treatment study

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    Background: Supplementation of vitamin D2 or vitamin D3 is recommended for vitamin D deficiency. Weekly supplementation of 60,000 IU of vitamin D3 increases serum 25(OH) D to optimal values. Various marketed forms of vitamin D3 include tablets, capsule, granules and oral solution. The main objective of this study is to compare the relative bioavailability of vitamin D3 oral solution with vitamin D3 tablet and capsule.Methods: This is an open-label, randomized, single-dose, three-treatment study to compare the relative bioavailability of vitamin D3 oral solution with capsule and tablet. Subjects (n=70) were supplemented with single dose of one of these formulations and their blood sample were assessed for Cmax, AUC0-28d and Tmax.Results: The logarithmic transformed data of pharmacokinetic parameters were analyzed for 90% Confidence Intervals (CI) using ANOVA. The mean (90% CI) values of vitamin D3 oral solution against tablet for the ratio of Cmax and AUC0-28d were 113.00 (105.32-121.23) and 105.54 (97.95-113.72) respectively. The mean (90% CI) values of vitamin D3 oral solution against capsule for the ratio of Cmax and AUC0-28d were 115.02 (106.38 - 124.37) and 112.33 (104.44 - 120.81) respectively. These values were within the bioequivalence range of 80-125%.Conclusions: It is concluded that vitamin D3 Oral Solution formulated with nanotechnology is bioequivalent to vitamin D3 tablet and capsule. However, oral solution of vitamin D3 shows higher Cmax and AUC when compared to tablet and capsule formulations

    A persistent scatterer interferometry procedure to monitor urban subsidence

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    This paper describes a Persistent Scatterer Interferometry procedure for deformation monitoring. Its more original part concerns an approach to estimate the atmospheric phase component. The procedure can be used to monitor deformation areas that are relatively small and are surrounded by stable areas. The proposed procedure is described step by step. The procedure can be applied using SAR data coming from different sensors. However, in this work we discuss results obtained using Sentinel-1 data. A case study is described, where the deformation is caused by water pumping associated with construction works. In this case study, a stack of 78 Sentinel-1 images were analysed. The main part of the paper concerns the analysis of the atmospheric component. A comprehensive characterization of this component is first described, considering the original non-filtered phases. This is followed by the characterization of the residual filtered phases. This analysis highlights the goodness of the proposed procedure. This is further confirmed by the analysis of two deformation time series. The procedure can work with any type of deformation phenomena, provided that its spatial extension is sufficiently small

    Molecular Identification of Delphinids and Finless Porpoise (Cetacea) from the Arabian Sea and Bay of Bengal

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    The exact number of extant delphinid species from seas around India is still debated and the lack of adequate field keys and reliable inventory has resulted in misidentification of several species. As a part of a project to develop a molecular taxonomy of cetaceans from this region, partial sequences of mtDNA cytochrome b were generated from accidentally caught/stranded delphinids and finless porpoise. Species were identified by phylogenetic reconstruction of sample sequences with the reference sequences available in portals GenBank (NCBI) and the web-based program DNA Surveillance. A comparison was made with the homologous sequences of corresponding species from other seas of the world. Our molecular investigations allowed us to identify five species of cetaceans from Indian coasts, including Delphinus capensis, previously reported as D. delphis. We detected unique haplotypes in Indo pacific humpbacked dolphin (Sousa chinensis; n = 2) and finless porpoise (Neophocaena phocaenoides; n = 12) from Indian coast. On the other hand, some haplotypes were shared with other regional populations in spinner dolphin (Stenella longirostris; n = 16) and bottlenose dolphin (Tursiops aduncus; n = 3). Common dolphins (Delphinus capensis; n = 2) had both unique and shared haplotypes including one highly divergent sequence

    Vacuum ultraviolet and infrared spectra of condensed methyl acetate on cold astrochemical dust analogs

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    Following the recent report of the first identification of methyl acetate (CH3COOCH3) in the interstellar medium (ISM) we have carried out Vacuum UltraViolet (VUV) and InfraRed (IR) spectroscopy studies on methyl acetate from 10 K until sublimation in an ultrahigh vacuum (UHV) chamber simulating astrochemical conditions. We present the first VUV and IR spectra of methyl acetate relevant to ISM conditions. Spectral signatures clearly showed molecular reorientation to have started in the ice by annealing the amorphous ice formed at 10 K. An irreversible phase change from amorphous to crystalline methyl acetate ice was found to be between 110 K and 120 K
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