382 research outputs found

    Spatial ordering due to hydrodynamic interactions between a pair of colliding drops in a confined shear

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    Pair-collision between viscous drops in a confined shear is numerically simulated to show that the confinement drastically alters the trajectories of the drops. In contrast to free shear, drops here move towards the centerline giving rise to a zero cross-stream separation and a net stream-wise separation. The latter varies as inverse of capillary number and the cube of the confinement (distance between the walls). The stream-wise separation does not depend on the initial positions of the drops. An analytical theory for the phenomenon is offered

    Effect of Dry Density and Salt Solution on Swelling Pressure of Compacted Bentonite

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    In many underground nuclear waste disposal facilities, bentonite has been referred as buffer and backfilling materials due to its high swelling capability, high water holding ability and low permeability. Since bentonite gets limited space for occupying itself around the underground nuclear waste containers and in case of water intrusion to the nuclear waste disposal repository, it exerts swelling pressure, therefore, the determination of swelling pressures of compacted bentonites is a significant aspect for such kind of bentonite-built barrier systems. Many of the waste repositories are commissioned in locations where the ground water either contains significant amount of salts or the repositories are anticipated to receive saline water from sea. Hence in this current research, an effort has been made to find out the swelling pressure of compacted bentonites under the influence of dry density and salt solution. Constant volume swelling pressure tests were carried out with compacted bentonite specimens of targeted dry densities varying between 1.2 to 1.8 Mg/m3 using distilled water and solutions of NaCl (0.5 and 1.0 M) as the hydrating ?uids. It was found that the swelling pressure of compacted bentonite specimens increased with increase in dry density.In all the cases,the equilibrium swelling pressures were found to reach within about 7 days for all cases irrespective of the dry density and the bulk solution. However, the influence of saline solutions was found to decrease the swelling pressure of the bentonite

    The innate immune response to Mycobacterium tuberculosis is dependent on strain lineage and on host population

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    Includes abstract.Includes bibliographical references.The genome structure of Mycobacterium tuberculosis is strongly clonal, in the absence of horizontal gene transfer. Thus it is feasible that clonal lineages may exhibit particular phenotypic characteristics, which may, in turn, result in differences in virulence or influence their association with particular host populations. Indeed, the global distribution of M. tuberculosis strains is not uniform and certain strain lineages predominate in particular geographical areas. Further, there is evidence that some strain lineages are emerging, suggesting differences in virulence. Firstly, we investigated the association between strain genotype of M. tuberculosis and in vitro correlates of virulence such as growth phenotype and cytokine induction in the monocyte-derived macrophage (MDM) model

    Rain Attenuation at 13 GHz over a LOS Terrestrial Link Situated in Indian Eastern Sector

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    Demographics and follow up of post partum intra-uterine copper device in tertiary hospital in Delhi, India

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    Background: Increasing unintended pregnancies in post partum females in our country warrants urgent attention towards prevalence and efficacy of contraceptives used. This study was done to determine the prevalence of PPIUCD and its follow up in patients attending tertiary hospital in New Delhi, India.Methods: Prospective study was carried in Department of Obstetrics and Gynecology, Dr. RML Hospital, New Delhi, India over a period of 1 year from July 2017 to July 2018. The awareness and prevalence of PPIUCD was assessed. At 6 week follow-up visit, women with PPIUCD were asked for symptoms of unusual vaginal discharge, irregular or heavy bleeding per vagina, and any expulsions if noticed. All the data was recorded and assessed.Results: Out of 1478 deliveries, 1372 were eligible for PPIUCD. 335 patients got PPIUCD inserted. 295 patients were followed as 40 patients were lost to follow up. 79.3% women did not have any complaints. 11.8%, 1% and 7.4% women had only heavy menstrual bleeding, only lower abdominal pain and both symptoms respectively. Spontaneous expulsion rate was noted in one patient (0.3%) at 6 weeks. IUCD removal was done in 4 patients who had complaints of pain and heavy menstrual bleeding not conservatively managed.Conclusions: PPIUCD insertion is a safe, convenient and effective method of contraception. The benefits of contraception immediately after delivery outweigh disadvantage of complications. Antenatal counseling and follow up in hospitals need to be strengthened to increase awareness and acceptability of PPIUCD

    Impact of Deadly Dust Storms (May 2018) on Air Quality, Meteorological, and Atmospheric Parameters Over the Northern Parts of India

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    The northern part of India, adjoining the Himalaya, is considered as one of the global hot spots of pollution because of various natural and anthropogenic factors. Throughout the year, the region is affected by pollution from various sources like dust, biomass burning, industrial and vehicular pollution, and myriad other anthropogenic emissions. These sources affect the air quality and health of millions of people who live in the Indo‐Gangetic Plains. The dust storms that occur during the premonsoon months of March–June every year are one of the principal sources of pollution and originate from the source region of Arabian Peninsula and the Thar desert located in north‐western India. In the year 2018, month of May, three back‐to‐back major dust storms occurred that caused massive damage, loss of human lives, and loss to property and had an impact on air quality and human health. In this paper, we combine observations from ground stations, satellites, and radiosonde networks to assess the impact of dust events in the month of May 2018, on meteorological parameters, aerosol properties, and air quality. We observed widespread changes associated with aerosol loadings, humidity, and vertical advection patterns with displacements of major trace and greenhouse gasses. We also notice drastic changes in suspended particulate matter concentrations, all of which can have significant ramifications in terms of human health and changes in weather pattern

    Studying the morphology of HI isodensity surfaces during reionization using Shapefinders and percolation analysis

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    Minkowski functionals and Shapefinders shed light on the connectedness of large-scale structure by determining its topology and morphology. We use a sophisticated code, SURFGEN2, to measure the Minkowski functionals and Shapefinders of individual clusters by modelling cluster surfaces using the Marching Cube 33 triangulation algorithm. In this paper, we study the morphology of simulated neutral hydrogen (HI) density fields using Shapefinders at various stages of reionization from the excursion set approach. Accompanying the Shapefinders, we also employ the ‘largest cluster statistic’ to understand the percolation process. Percolation curves demonstrate that the non-Gaussianity in the H I field increases as reionization progresses. The large clusters in both the H I overdense and underdense excursion sets possess similar values of ‘thickness’ (T), as well as ‘breadth’ (B), but their third Shapefinder – ‘length’ (L) – becomes almost proportional to their volume. The large clusters in both H I overdense and underdense segments are overwhelmingly filamentary. The ‘cross-section’ of a filamentary cluster can be estimated using the product of the first two Shapefinders, T × B. Hence the cross-sections of the large clusters at the onset of percolation do not vary much with volume and their sizes only differ in terms of their lengths. This feature appears more vividly in H I overdense regions than in underdense regions and is more pronounced at lower redshifts which correspond to an advanced stage of reionization

    Modern lineages of Mycobacterium tuberculosis exhibit lineage-specific patterns of growth and cytokine induction in human monocyte-derived macrophages

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    BACKGROUND: Strains of Mycobacterium tuberculosis vary in virulence. Strains that have caused outbreaks in the United States and United Kingdom have been shown to subvert the innate immune response as a potential immune evasion mechanism. There is, however, little information available as to whether these patterns of immune subversion are features of individual strains or characteristic of broad clonal lineages of M. tuberculosis . METHODS: Strains from two major modern lineages (lineage 2 [East-Asian] and lineage 4 [Euro-American]) circulating in the Western Cape in South Africa as well as a comparator modern lineage (lineage 3 [CAS/Delhi]) were identified. We assessed two virulence associated characteristics: mycobacterial growth (in liquid broth and monocyte derived macrophages) and early pro-inflammatory cytokine induction. RESULTS: In liquid culture, Lineage 4 strains grew more rapidly and reached higher plateau levels than other strains (lineage 4 vs. lineage 2 p = 0.0024; lineage 4 vs. lineage 3 p = 0.0005). Lineage 3 strains were characterized by low and early plateau levels, while lineage 2 strains showed an intermediate growth phenotype. In monocyte-derived macrophages, lineage 2 strains grew faster than lineage 3 strains (p<0.01) with lineage 4 strains having an intermediate phenotype. Lineage 2 strains induced the lowest levels of pro-inflammatory TNF and IL-12p40 as compared to other lineages (lineage 2: median TNF 362 pg/ml, IL-12p40 91 pg/ml; lineage 3: median TNF 1818 pg/ml, IL-12p40 123 pg/ml; lineage 4: median TNF 1207 pg/ml, IL-12p40 205 pg/ml;). In contrast, lineage 4 strains induced high levels of IL-12p40 and intermediate level of TNF. Lineage 3 strains induced high levels of TNF and intermediate levels of IL-12p40. CONCLUSIONS: Strains of M. tuberculosis from the three major modern strain lineages possess distinct patterns of growth and cytokine induction. Rapid growth and immune subversion may be key characteristics to the success of these strains in different human populations
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