1,198 research outputs found

    Synthesis and superconductivity of new BiS2 based superconductor PrO0.5F0.5BiS2

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    We report synthesis and superconductivity at 3.7K in PrO0.5F0.5BiS2. The newly discovered material belongs to the layered sulfide based REO0.5F0.5BiS2 compounds having ZrCuSiAs type structure. The bulk polycrystalline compound is synthesized by vacuum encapsulation technique at 7800C in single step. Detailed structural analysis has shown that the as synthesized PrO0.5F0.5BiS2 is crystallized in tetragonal P4/nmm space group with lattice parameters a = 4.015(5) {\AA}, c = 13.362(4) {\AA}. Bulk superconductivity is observed in PrO0.5F0.5BiS2 below 4K from magnetic and transport measurements. Electrical transport measurements showed superconducting transition temperature (Tc) onset at 3.7K and Tc ({\rho}=0) at 3.1K. Hump at Tc related to superconducting transition is not observed in heat capacity measurement and rather a Schottky-type anomaly is observed at below ~6K. The compound is slightly semiconducting in normal state. Isothermal magnetization (MH) exhibited typical type II behavior with lower critical field (Hc1) of around 8Oe.Comment: Short note 10 pages text+figs. First report on PrO.5F.5BiS2 Su

    Superconducting Mechanism through direct and redox layer doping in Pnictides

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    The mechanism of superconductivity in pnictides is discussed through direct doping in superconducting FeAs and also in charge reservoir REO layers. The un-doped SmFeAsO is charge neutral SDW (Spin Density Wave) compound with magnetic ordering below 150 K. The Superconducting FeAs layers are doped with Co and Ni at Fe site, whereas REO layers are doped with F at O site. The electron doping in SmFeAsO through Co results in superconductivity with transition temperature (Tc) maximum up to 15 K, whereas F doping results in Tc upto 47 K in SmFeAsO. All these REFe/Co/NiAsO/F compounds are iso-structural to ZrCuSiAs structure. The samples are crystallized in a tetragonal structure with space group P4/nmm. Variation of Tc with different doping routes shows the versatility of the structure and mechanism of occurrence of superconductivity. It seems doping in redox layer is more effective than direct doping in superconducting FeAs layer.Comment: 4 Pages text + Figs: ([email protected]

    Anti-inflammatory and ulcerogenic activities of thiazolidine-4-ones in rats

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    Background: NSAIDS are associated with side effects and research should continue for developing safer drugs. This study aims to evaluate newer thiazolidine-4-ones for their anti-inflammatory and ulcerogenic activities in wister rats.Methods: Five groups of wister rats, 6 in each were used.  Anti-inflammatory and ulcerogenic activities of diclofenac (30mg/kg), nimesulide (50mg/kg), thia-1 (50mg/kg) and thia-2 (50mg/kg) are compared with control group (4% Gum Acacia). Carrageenin-induced paw edema, formaline induced acute peritonitis and cotton pellet-induced granulomatous tissue formation models were used for evaluating anti-inflammatory activity. After removing cotton pellets with granuloma on 8th day gastric ulcerogenicity was assessed by using macroscopic and microscopic scoring of ulcers.Results: Diclofenac, nimesulide and thia 2 reduced both paw edema and peritoneal exudate volume significantly (p 0.05). Nimesulide, thia-1 and thia-2 did not increase gastric ulcer score significantly (p >0.05). Diclofenac increased ulcer score significantly (p <0.01).Conclusions: Thia-2 demonstrated significant anti-inflammatory activity in acute and chronic models. In addition to inhibition of cyclooxygenase pathway, PPAR agonistic activity may be involved in its anti-inflammatory activity.  No significant ulcerogenicity was observed on comparing with nimesulide and control. Further in-vitro and in-vivo studies are recommended to confirm the results of this study

    Magnetization and Magneto-resistance in Y(Ba1-xSrx)2Cu3O7-{\delta} (x = 0.00 - 0.50) superconductor

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    Here we present the magnetic properties and upper critical field (BC2) of polycrystalline Y(Ba1-xSrx)2Cu3O7-{\delta} superconductors, which are being determined through detailed ac/dc susceptibility and resistivity under magnetic field (RTH) study. All the samples are synthesized through solid state reaction route. Reduction in Meissner fraction (the ratio of field cooled to zero field cooled magnetization) is observed with increasing Sr content, suggesting occurrence of flux pining in the doped samples. The ac susceptibility and resistivity measurements reveal improved grain couplings in Sr substituted samples. Consequently the inter-grain critical current density (Jc), upturn curvature near the Tc in temperature dependence of upper critical field [BC2(T)], and BC2 are enhanced. Both Jc and BC2 increase in lower Sr substitution (up to x = 0.10) samples followed by decrease in higher doping due to degradation in effective pining and grain coupling.Comment: 17 pages text + Figs, [email protected]

    Surgical management of vaginal agenesis using a modified Mc Indoe’s technique: VIMS experience

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    Background: Mullerian agenesis is a challenge to reconstructive surgeons. In order to create a new vagina that mimic the normal one in size, lining and appearance, multiple techniques have been designed; among these techniques Mc Indoe’s vaginoplasty represents the simplest one with good results. Mc Indoe’s operation which involves the creation of a space between bladder and rectum, insertion of a mould covered with split-thickness skin graft into that neo-vaginal space, and use of postoperative vaginal mould for dilation and to avoid stenosis. However, many modifications have been introduced in time in an attempt to increase the success rates. The purpose of vaginal agencies treatment is to create an adequate passage for penetration during sexual intercourse.Methods: Between Jan 2010 to June 2017, ten patients with vaginal agenesis were admitted to Dept of Obstetrics and Gynaecology, VIMS Ballari for vaginal reconstruction. All cases underwent a modified Mc Indoe’s technique, and follow up was done for one year.Results: All ten cases of vaginal agenesis underwent vaginal reconstruction by modified Mc Indoe's technique. Post-operative vaginal length varied from 5 to 7 cm in patients who used mould regularly. Successful skin graft take was achieved in 6 cases. one case of perforation of rectum and one case of vaginal stricture was noted.Conclusions: To optimize sexual comfort, the clinical management of women with vaginal agenesis must be multidisciplinary and individually tailored. Our findings suggest that the modified Mc Indoe’s technique is a simple, effective procedure for the treatment of vaginal agenesis, but proper mould usage after surgery remains the cornerstone of the treatment

    Assessment of PlanIQ Feasibility DVH for head and neck treatment planning

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    INTRODUCTION: Designing a radiation plan that optimally delivers both target coverage and normal tissue sparing is challenging. There are limited tools to determine what is dosimetrically achievable and frequently the experience of the planner/physician is relied upon to make these determinations. PlanIQ software provides a tool that uses target and organ at risk (OAR) geometry to indicate the difficulty of achieving different points for organ dose-volume histograms (DVH). We hypothesized that PlanIQ Feasibility DVH may aid planners in reducing dose to OARs. METHODS AND MATERIALS: Clinically delivered head and neck treatments (clinical plan) were re-planned (re-plan) putting high emphasis on maximally sparing the contralateral parotid gland, contralateral submandibular gland, and larynx while maintaining routine clinical dosimetric objectives. The planner was blinded to the results of the clinically delivered plan as well as the Feasibility DVHs from PlanIQ. The re-plan treatments were designed using 3-arc VMAT in Raystation (RaySearch Laboratories, Sweden). The planner was then given the results from the PlanIQ Feasibility DVH analysis and developed an additional plan incorporating this information using 4-arc VMAT (IQ plan). The DVHs across the three treatment plans were compared with what was deemed "impossible" by PlanIQ's Feasibility DVH (Impossible DVH). The impossible DVH (red) is defined as the DVH generated using the minimal dose that any voxel outside the targets must receive given 100% target coverage. RESULTS: The re-plans performed blinded to PlanIQ Feasibilty DVH achieved superior sparing of aforementioned OARs compared to the clinically delivered plans and resulted in discrepancies from the impossible DVHs by an average of 200-700 cGy. Using the PlanIQ Feasibility DVH led to additionalOAR sparing compared to both the re-plans and clinical plans and reduced the discrepancies from the impossible DVHs to an average of approximately 100 cGy. The dose reduction from clinical to re-plan and re-plan to IQ plan were significantly different even when taking into account multiple hypothesis testing for both the contralateral parotid and the larynx (P < 0.004 for all comparisons). No significant differences were observed between the three plans for the contralateral parotid when considering multiple hypothesis testing. CONCLUSIONS: Clinical treatment plans and blinded re-plans were found to suboptimally spare OARs. PlanIQ could aid planners in generating treatment plans that push the limits of OAR sparing while maintaining routine clinical target coverage goals
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