338 research outputs found

    Time-gated optical imaging through turbid media using stimulated Raman scattering: studies on image contrast

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    In this paper, we report the development of experimental set-up for time-gated optical imaging through turbid media using stimulated Raman scattering. Our studies on the contrast of time-gated images show that for a given optical thickness, the image contrast is better for sample with lower scattering coefficient and higher physical thickness, and that the contrast improves with decreasing value of anisotropy parameters of the scatterers. These results are consistent with time-resolved Monte Carlo simulations

    Non-invasive ophthalmic imaging of adult zebrafish eye using optical coherence tomography

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    We describe the development of a single-mode fibre based optical coherence tomography set-up and its use for non-invasive optical imaging of adult zebrafish (Danio rerio) eyes. The free-space axial and lateral resolutions of the set-up were estimated to be ~ 11 and 17 μm respectively. Images of whole eye, cornea and retina acquired with the set-up have been used to estimate several ocular parameters, viz. corneal thickness, mean retinal thickness and effective refractive index of the crystalline lens

    Origin and Diversification of Major Clades in Parmelioid Lichens (Parmeliaceae, Ascomycota) during the Paleogene Inferred by Bayesian Analysis

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    There is a long-standing debate on the extent of vicariance and long-distance dispersal events to explain the current distribution of organisms, especially in those with small diaspores potentially prone to long-distance dispersal. Age estimates of clades play a crucial role in evaluating the impact of these processes. The aim of this study is to understand the evolutionary history of the largest clade of macrolichens, the parmelioid lichens (Parmeliaceae, Lecanoromycetes, Ascomycota) by dating the origin of the group and its major lineages. They have a worldwide distribution with centers of distribution in the Neo- and Paleotropics, and semi-arid subtropical regions of the Southern Hemisphere. Phylogenetic analyses were performed using DNA sequences of nuLSU and mtSSU rDNA, and the protein-coding RPB1 gene. The three DNA regions had different evolutionary rates: RPB1 gave a rate two to four times higher than nuLSU and mtSSU. Divergence times of the major clades were estimated with partitioned BEAST analyses allowing different rates for each DNA region and using a relaxed clock model. Three calibrations points were used to date the tree: an inferred age at the stem of Lecanoromycetes, and two dated fossils: Parmelia in the parmelioid group, and Alectoria. Palaeoclimatic conditions and the palaeogeological area cladogram were compared to the dated phylogeny of parmelioid. The parmelioid group diversified around the K/T boundary, and the major clades diverged during the Eocene and Oligocene. The radiation of the genera occurred through globally changing climatic condition of the early Oligocene, Miocene and early Pliocene. The estimated divergence times are consistent with long-distance dispersal events being the major factor to explain the biogeographical distribution patterns of Southern Hemisphere parmelioids, especially for Africa-Australia disjunctions, because the sequential break-up of Gondwana started much earlier than the origin of these clades. However, our data cannot reject vicariance to explain South America-Australia disjunctions

    Remedial Prospective of Hippophae rhamnoides Linn. (Sea Buckthorn)

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    Sea buckthorn (Hippophae rhamnoides L.) constitutes thorny nitrogen fixing deciduous shrub. Sea buckthorn(SBT) is primarily valued for its very rich vitamins A, B1, B12, C, E, K, and P; flavonoids, lycopene, carotenoids, and phytosterols. and therapeutically important since it is rich with potent antioxidants. Scientifically evaluated pharmacological actions of SBT are like inflammation inhibited by reduced permeability, loss of follicular aggregation of lymphocytes from the inflamed synovium and suppress lymphocyte proliferation. SBT-reduced recurrence of angina, ischemic electrocardiogram which might be due to decreased myocardial oxygen consumption and inhibition of platelet aggregation induced by collagen. SBT can kill both cancer cells of S180, P388, SGC7901 and lymphatic leukemia (L1200). The antiulcer activity may be related to reduce gastric empty time, inhibiting proteolytic activity and promoting wound reparation processes of mucosa. SBT exerts antihypertensive effect in part by blocking angiotensin-2 receptor on cell surface. SBT decreased the level of stress hormones and enhanced hypoxic tolerance in animals indicating its anti-stress, adaptogenic activity. A lot of research work is still needed to find cellular and molecular mechanisms of these activities and also yet to be explored for its activity in osteoporosis, hemorrhage, cataract, urinary stone, acne, psoriasis, polyneuritis, cheilosis, glossities, baldness, anti-obesity, gout, and chronic prostitis

    Direct observation of the flux-line vortex glass phase in a type II superconductor

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    The order of the vortex state in La_{1.9} Sr_{0.1} CuO_{4} is probed using muon spin rotation and small-angle neutron scattering. A transition from a Bragg glass to a vortex glass is observed, where the latter is composed of disordered vortex lines. In the vicinity of the transition the microscopic behavior reflects a delicate interplay of thermally-induced and pinning-induced disorder.Comment: 14 pages, 4 colour figures include

    FIGO postpartum intrauterine device initiative: Complication rates across six countries.

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    OBJECTIVE: To record and analyze complication rates following postpartum intrauterine device (PPIUD) insertion in 48 hospitals in six countries: Sri Lanka, India, Nepal, Bangladesh, Tanzania, and Kenya. METHODS: Healthcare providers were trained in counselling and insertion of PPIUD via a training-the-trainer model. Data were collected on methodology, timing, cadre of staff providing care, and number of insertions. Data on complications were collected at 6-week follow-up. Statistical analysis was performed to elucidate factors associated with increased expulsion and absence of threads. RESULTS: From May 2014 to September 2017, 36 766 PPIUDs were inserted: 53% vaginal and 47% at cesarean delivery; 74% were inserted by doctors. Follow-up was attended by 52%. Expulsion and removal rates were 2.5% and 3.6%, respectively. Threads were not visible in 29%. Expulsion was less likely after cesarean insertion (aOR 0.33; 95% CI, 0.26-0.41), following vaginal insertion at between 10 minutes and 48 hours (aOR 0.59; 95% CI, 0.42-0.83), and when insertion was performed by a nurse (aOR 0.33; 95% CI, 0.22-0.50). CONCLUSION: PPIUD has low complication rates and can be safely inserted by a variety of trained health staff. Given the immediate benefit of the one-stop approach, governments should urgently consider adopting this model

    Using target enrichment sequencing to study the higher-level phylogeny of the largest lichen-forming fungi family: Parmeliaceae (Ascomycota)

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    Parmeliaceae is the largest family of lichen-forming fungi with a worldwide distribution. We used a target enrichment data set and a qualitative selection method for 250 out of 350 genes to infer the phylogeny of the major clades in this family including 81 taxa, with both subfamilies and all seven major clades previously recognized in the subfamily Parmelioideae. The reduced genome-scale data set was analyzed using concatenated-based Bayesian inference and two different Maximum Likelihood analyses, and a coalescent-based species tree method. The resulting topology was strongly supported with the majority of nodes being fully supported in all three concatenated-based analyses. The two subfamilies and each of the seven major clades in Parmelioideae were strongly supported as monophyletic. In addition, most backbone relationships in the topology were recovered with high nodal support. The genus Parmotrema was found to be polyphyletic and consequently, it is suggested to accept the genus Crespoa to accommodate the species previously placed in Parmotrema subgen. Crespoa. This study demonstrates the power of reduced genome-scale data sets to resolve phylogenetic relationships with high support. Due to lower costs, target enrichment methods provide a promising avenue for phylogenetic studies including larger taxonomic/specimen sampling than whole genome data would allow

    Field-induced hexagonal to square transition of the vortex lattice in overdoped La{1.8}Sr{0.2}CuO{4}

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    We report on a small angle neutron scattering study of the vortex lattice in overdoped La{2-x}Sr{x}CuO{4} (x=0.2) up to high magnetic fields (9.5 Tesla) applied perpendicular to the CuO2 planes. At low magnetic fields we observe a crossover from hexagonal to square coordination of the vortex lattice. This field-induced transition confirms the results obtained in slightly overdoped La{2-x}Sr{x}CuO{4} (x=0.17).Comment: 3 pages, 2 figures. to appear in Physica C (proceedings for the M2S-HTSC-VII Conference, May 25-30, Rio de Janeiro
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