189 research outputs found

    Asymptomatic secondary abdominal pregnancy diagnosed 12 years after tubectomy

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    Abdominal pregnancy is a rare obstetric complication with high maternal mortality. Advanced abdominal pregnancy is rare and accounts for 1 in 25,000 pregnancies. 32 years’ lady, P2L2, last child birth and interval tubectomy by modified Pomeroy’s method 12 years ago, reported with Amenorrhoea of two months with vague lower abdominal pain since 2 days. Ultrasonography (USG) abdomen and pelvis showed an extrauterine viable pregnancy of 20+ weeks POG with no hemoperitoneum. she travelled 4 hours by road to her hometown, for second opinion and was referred back to our institution. A laparotomy was done; hemoperitoneum of 1.5 litres was noted. The sac with the live foetus inside with placental implantation seen on entire left fallopian tube except the fimbrial end and a small portion of omentum was noted. Left salpingectomy with excision of the sac with the foetus along with partial omentectomy was performed. Patient received two units of PRBC postoperatively

    Pulsed electrodeposition of Cuinse2 thin films with morphology for solar cell applications

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    Copper indium diselenide (CuInSe2) films have been prepared by pulse electrodeposition technique on Molybdenum substrate followed by post-deposition annealing at 550°C. Optimization of pulse parameters by varying the pulse duration (duty cycle) in order to achieve high quality films has been reported. Appropriate manipulation of pulse parameters has resulted in a novel flake-like crystallite morphology and better control over the composition of individual elements. The CIS thin films were comprehensively characterized using SEM-EDS, FIB, XRD and UV-DRS to study their morphology, phase constitution, etc. and PEC (photoelectrochemistry) measurements were also carried out to ascertain the photoelectrochemical performance of the CIS absorber layer. The bandgap of the CIS films was determined to be 1.02 eV. The flake like crystallite morphology observed in CIS thin films under the optimized processing conditions was found to yield enhanced cathodic photoresponse under solar simulated light with a photocurrent density of 20 μA/cm2 (observed at a potential of -0.6 V vs. SCE). The films exhibited a photoresponse typical of a p-type semiconducto

    Improved Photoelectrochemical Performance Of Cu(In,Ga)Se2 Thin Films Prepared By Pulsed Electrodeposition

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    Solar cells based on polycrystalline Cu(In,Ga)Se2 absorber layers have yielded the highest conversion efficiency among all the thin-film technologies. CIGS thin-films possess large optical absorption coefficient (≈105 cm-1) and a suitable bandgap of ≈ 1.20 eV for an ideal stoichiometry of CuIn0.7Ga0.3Se2. In the present study, Direct Current (DC) and Pulsed Current (PC) electrodeposition techniques are employed to obtain the near ideal stoichiometric CIGS thin-films on a Mo foil using a two electrode system at a constant potential. Deposited films are annealed at 550 °C under Ar atmosphere. Characterization of the annealed CIGS films is performed using SEM-energy dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, and photoelectrochemistry to study the morphology, stoichiometry, phase constitution, and the photoelectrochemical response. PC deposition offered suitable manipulation of various parameters, which has helped in obtaining a better quality stoichiometric single phase chalcopyrite structured CIGS thin films with the elimination of unwanted secondary phases like Cu2-xSe. An improved photoelectrochemical performance, characteristic of a p-type semiconductor, is observed for the PC deposited CIGS film

    Pulsed Electrochemical Deposition of CuInSe2 and Cu(In,Ga)Se2 Semiconductor Thin Films

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    CuInSe2 (CIS) and Cu(In,Ga)Se2 (CIGS) semiconductors are the most studied absorber materials for thin films solar cells due to their direct bandgap and large absorption coefficient. The highly efficient CIGS devices are often fabricated using expensive vacuum based technologies; however, recently electrodeposition has been demonstrated to produce CIGS devices with high efficiencies and it is easily amenable for large area films of high quality with effective material use and high deposition rate. In this context, this chapter discusses the recent developments in CIS and CIGS technologies using electrodeposition. In addition, the fundamental features of electrodeposition such as direct current, pulse and pulse-reverse plating and their application in the fabrication of CIS and CIGS films are discussed. In conclusion, the chapter summarizes the utilization of pulse electrodeposition for fabrication of CIS and CIGS films while making a recommendation for exploring the group’s unique pulse electroplating method

    CuIn1-xGaxSe2 thin-film absorber layers for solar photovoltaics fabricated by two-stage pulsed current electrodeposition

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    Single phase polycrystalline Copper Indium Gallium Diselenide (CIGS) thin-films for solar photovoltaic applications were fabricated by an economical two-stage method of Pulsed Current (PC) electrodeposition. Cu, Ga and Se were first co-deposited onto a Mo foil followed by deposition of In. The as-deposited films were annealed in Argon atmosphere at 550 C for 30 min and were further characterized to study their morphology, phase constitution, and optical absorption. The results revealed that the films have a compact morphology and are comprised of a crystalline chalcopyrite single phase CIGS. The bandgap of the CIGS films was found to be 1.27 eV from absorption studies. The photoelectrochemical studies revealed the p-type nature of CIGS films with improved photocurrent over that obtained for one-stage PC electrodeposited CIGS thin-film

    Photoelectrochemistry of Cu(In,Ga)Se2 thin-films fabricated by sequential pulsed electrodeposition

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    A novel approach for the fabrication of compact stoichiometric copper indium gallium selenium (CIGS) thin-films is reported. It uses a solution of CuCl2, GaCl3 and H2SeO3, pH adjusted with HCl with LiCl as additive employing a high purity graphite plate anode and Mo sputtered glass cathode during a simplified sequential pulsed current electrodeposition which avoids impurities from the use of a reference electrode during deposition and a separate selenization step. A Cu-Ga-Se film is optimally deposited by optimizing the deposition voltage, followed by deposition of In from InCl3 solution, and then annealing of the Cu-Ga-Se/In thin-film in an Argon atmosphere at 550 °C. A single phase chalcopyrite CIGS forms with a compact morphology and well-controlled composition of individual elements. The flat-band potential and carrier density of CIGS thin-films are −0.15 V and 2.6 × 1016 cm−3, respectively, as determined by Mott–Schottky studies. The photoelectrochemical performance of CIGS films shows a photocurrent density of −0.8 mA cm−2 at −0.4 V vs. SCE, an eight fold increment compared to our previous reported value. This simplified preparation using pulse plating gives superior quality CIGS films which are promising for application in thin-film solar cells and photoelectrochemical cells

    One-Dimensional Model of an Optimal Ejector and Parametric Study of Ejector Efficiency

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    Significant numerical and experimental analyses have been devoted to understanding the variety of flow regimes present in steady flow ejectors. Certain regimes are more conducive to achieving high performance (i.e. high entrainment ratios). In particular, the entrainment ratio is seen to be highest when the entrained fluid reaches a choked condition in the mixing region. In addition, the expansion regime of the motive nozzle (under-, perfectly- or over-expanded) appears to influence performance. In this paper, we propose a method to model an ejector of optimal geometry, designed for a favorable flow regime. Then, rather than focusing upon the maximization of efficiency, we seek operational conditions that maximise ejector efficiency, specifically the reversible entrainment ratio efficiency. Ejector efficiency is found to be highest at low compression ratios and at low driving pressure ratios. However, at lower compression ratios, the optimal area of the mixing chamber becomes large relative to the motive nozzle throat area.United States. J. William Fulbright Foreign Scholarship Board (Science and Technology PhD Program)Center for Clean Water and Clean Energy at MIT and KFUP

    A new cache of Eoarchaean detrital zircons from the Singhbhum craton, eastern India and constraints on early Earth geodynamics

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    The dominant geodynamic processes that underpin the formation and evolution of Earth's early crust remain enigmatic calling for new information from less studied ancient cratonic nuclei. Here, we present U–Pb ages and Hf isotopic compositions of detrital zircon grains from ∼2.9 Ga old quartzites and magmatic zircon from a 3.505 Ga old dacite from the Iron Ore Group of the Singhbhum craton, eastern India. The detrital zircon grains range in age between 3.95 Ga and 2.91 Ga. Together with the recently reported Hadean, Eoarchean xenocrystic (up to 4.24 Ga) and modern detritus zircon grains from the Singhbhum craton, our results suggest that the Eoarchean detrital zircons represent crust generated by recycling of Hadean felsic crust formed at ∼4.3–4.2 Ga and ∼3.95 Ga. We observe a prominent shift in Hf isotope compositions at ∼3.6–3.5 Ga towards super-chondritic values, which signify an increased role for depleted mantle and the relevance of plate tectonics. The Paleo-, Mesoarchean zircon Hf isotopic record in the craton indicates crust generation involving the role of both depleted and enriched mantle sources. We infer a short-lived suprasubduction setting around ∼3.6–3.5 Ga followed by mantle plume activity during the Paleo-, Mesoarchean crust formation in the Singhbhum craton. The Singhbhum craton provides an additional repository for Earth's oldest materials.Financial support from the Ministry of Earth Sciences, New Delhi for Excimer 193 nm LA system at CSIR-NGRI MoES/P.O.(Seismo)/1(245)/2014 and for the project on Singhbhum craton to S. D., E. V. S. S. K. B., B. S. and T. V. K (No. MoES/ P.O.(Geosci)45/2015; GAP-738-28EVB). This work forms part of the CSIR-NGRI projects INDEX (PSC0204) and GEOMET. Support from Australian Scientific Instruments and Geoscience Australia in providing access to the SHRIMP IIe, and The ANU for SEM imaging, is acknowledged. Y. J. B. thanks the DAE-Raja Ramanna Fellowship

    The Herbal Drug Melampyrum pratense

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    Melampyrum pratense L. (Koch) is used in traditional Austrian medicine for the treatment of different inflammation-related conditions. In this work, we show that the extracts of M. pratense stimulated peroxisome proliferator-activated receptors- (PPARs-)α and -γ that are well recognized for their anti-inflammatory activities. Furthermore, the extract inhibited the activation of the proinflammatory transcription factor NF-κB and induction of its target genes interleukin-8 (IL-8) and E-selectin in vitro. Bioassay-guided fractionation identified several active flavonoids and iridoids including melampyroside and mussaenoside and the phenolic compound lunularin that were identified in this species for the first time. The flavonoids apigenin and luteolin were distinguished as the main components accountable for the anti-inflammatory properties. Apigenin and luteolin effectively inhibited tumor necrosis factor α (TNF-α)-induced NF-κB-mediated transactivation of a luciferase reporter gene. Furthermore, the two compounds dose-dependently reduced IL-8 and E-selectin protein expression after stimulation with lipopolysaccharide (LPS) or TNF-α in endothelial cells (ECs). The iridoids melampyroside and mussaenoside prevented the elevation of E-selectin in LPS-stimulated ECs. Lunularin was found to reduce the protein levels of the proinflammatory mediators E-selectin and IL-8 in ECs in response to LPS. These data validate the ethnomedical use of M. pratense for the treatment of inflammatory conditions and point to the constituents accountable for its anti-inflammatory activity

    Phosphoenolpyruvate carboxylase dentified as a key enzyme in erythrocytic Plasmodium falciparum carbon metabolism

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    Phospoenolpyruvate carboxylase (PEPC) is absent from humans but encoded in thePlasmodium falciparum genome, suggesting that PEPC has a parasite-specific function. To investigate its importance in P. falciparum, we generated a pepc null mutant (D10Δpepc), which was only achievable when malate, a reduction product of oxaloacetate, was added to the growth medium. D10Δpepc had a severe growth defect in vitro, which was partially reversed by addition of malate or fumarate, suggesting that pepc may be essential in vivo. Targeted metabolomics using 13C-U-D-glucose and 13C-bicarbonate showed that the conversion of glycolytically-derived PEP into malate, fumarate, aspartate and citrate was abolished in D10Δpepc and that pentose phosphate pathway metabolites and glycerol 3-phosphate were present at increased levels. In contrast, metabolism of the carbon skeleton of 13C,15N-U-glutamine was similar in both parasite lines, although the flux was lower in D10Δpepc; it also confirmed the operation of a complete forward TCA cycle in the wild type parasite. Overall, these data confirm the CO2 fixing activity of PEPC and suggest that it provides metabolites essential for TCA cycle anaplerosis and the maintenance of cytosolic and mitochondrial redox balance. Moreover, these findings imply that PEPC may be an exploitable target for future drug discovery
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