2,045 research outputs found

    CLINICAL FEATURES AND PATTERN OF PRESENTATION OF BREAST DISEASES IN SURGICAL OUTPATIENT CLINIC OF A TERTIARY HOSPITAL

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    Objective: The objective of thedu was to characterize the clinical features and pattern of presentation of breast diseases as observed in our practice. Materials and Methods: A prospective study of 121 consecutive patients with breast complaints presenting in our Surgical Outpatient Clinics. The relevant data were collected using the prescribed forms and was analyzed using Epi Info 2003, Mann–Whitney (test of two groups) Chi-squared and Fishers exact test was used to compare parameters of benign and malignant groups. P value <0.05 was considered as significant. Results: One hundred and nineteen patients were females, two were males. The age range was 14–70 years. Forty two (34.7%) patients were in the 21–30 year age group. The commonest symptoms were breast lump in 111 (91.7%) patients, and breast pain in 28 (23.1%) patients. Breast pain was a significant presenting complaint in patients with breast malignancy (P=0.026). On clinical examination 103 (85.1%) patients had palpable lumps, and seven patients were normal. Forty four patients (36.3%) had malignant disease, seventy patients (57.8%) had benign breast diseases and seven were normal. Fifty nine of the 70 benign diseases were fibroadenoma. One hundred and three patients (85%) had appropriate therapy, while 18 patients (14.8%), including eight with malignant disease absconded. Conclusion: In the study, a breast lump was the commonest clinical feature of breast disease. Over 60% of these were benign. Breast pain was a statistically significant presentation in patients with malignant breast disease. One in seven of the patients absconded

    Electromagnetic Interference in an Implantable Loop Recorder Caused by a Portable Digital Media Player

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75458/1/j.1540-8159.2008.01188.x.pd

    A templating approach to controlling the growth of coevaporated halide perovskites

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    Metal halide perovskite semiconductors have shown significant potential for use in photovoltaic (PV) devices. While fabrication of perovskite thin films can be achieved through a variety of techniques, thermal vapor deposition is particularly promising, allowing for high-throughput fabrication. However, the ability to control the nucleation and growth of these materials, particularly at the charge-transport layer/perovskite interface, is critical to unlocking the full potential of vapor-deposited perovskite PV. In this study, we explore the use of a templating layer to control the growth of coevaporated perovskite films and find that such templating leads to highly oriented films with identical morphology, crystal structure, and optoelectronic properties independent of the underlying layers. Solar cells incorporating templated FA0.9Cs0.1PbI3–xClx show marked improvements with steady-state power conversion efficiency over 19.8%. Our findings provide a straightforward and reproducible method of controlling the charge-transport layer/coevaporated perovskite interface, further clearing the path toward large-scale fabrication of efficient PV devices

    Elucidating the long-range charge carrier mobility in metal halide perovskite thin films

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    Many optoelectronic properties have been reported for lead halide perovskite polycrystalline films. However, ambiguities in the evaluation of these properties remain, especially for long-range lateral charge transport, where ionic conduction can complicate interpretation of data. Here we demonstrate a new technique to measure the long-range charge carrier mobility in such materials. We combine quasi-steady-state photo-conductivity measurements (electrical probe) with photo-induced transmission and reflection measurements (optical probe) to simultaneously evaluate the conductivity and charge carrier density. With this knowledge we determine the lateral mobility to be ~ 2 cm2/Vs for CH3NH3PbI3 (MAPbI3) polycrystalline perovskite films prepared from the acetonitrile/methylamine solvent system. Furthermore, we present significant differences in long-range charge carrier mobilities, from 2.2 to 0.2 cm2/Vs, between films of contemporary perovskite compositions prepared via different fabrication processes, including solution and vapour phase deposition techniques. Arguably, our work provides the first accurate evaluation of the long-range lateral charge carrier mobility in lead halide perovskite films, with charge carrier density in the range typically achieved under photovoltaic operation

    Growth modes and quantum confinement in ultrathin vapour-deposited MAPbI₃ films

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    Vapour deposition of metal halide perovskite by co-evaporation of precursors has the potential to achieve large-area high-efficiency solar cells on an industrial scale, yet little is known about the growth of metal halide perovskites by this method at the current time. Here, we report the fabrication of MAPbI3 films with average thicknesses from 2–320 nm by co-evaporation. We analyze the film properties using X-ray diffraction, optical absorption and photoluminescence (PL) to provide insights into the nucleation and growth of MAPbI3 films on quartz substrates. We find that the perovskite initially forms crystallite islands of around 8 nm in height, which may be the cause of the persistent small grain sizes reported for evaporated metal halide perovskites that hinder device efficiency and stability. As more material is added, islands coalesce until full coverage of the substrate is reached at around 10 nm average thickness. We also find that quantum confinement induces substantial shifts to the PL wavelength when the average thickness is below 40 nm, offering dual-source vapour deposition as an alternative method of fabricating nanoscale structures for LEDs and other devices

    Perovskite-perovskite tandem photovoltaics with optimized bandgaps

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    We demonstrate four and two-terminal perovskite-perovskite tandem solar cells with ideally matched bandgaps. We develop an infrared absorbing 1.2eV bandgap perovskite, FA0.75Cs0.25Sn0.5Pb0.5I3FA_{0.75}Cs_{0.25}Sn_{0.5}Pb_{0.5}I_3, that can deliver 14.8 % efficiency. By combining this material with a wider bandgap FA0.83Cs0.17Pb(I0.5Br0.5)3FA_{0.83}Cs_{0.17}Pb(I_{0.5}Br_{0.5})_3 material, we reach monolithic two terminal tandem efficiencies of 17.0 % with over 1.65 volts open-circuit voltage. We also make mechanically stacked four terminal tandem cells and obtain 20.3 % efficiency. Crucially, we find that our infrared absorbing perovskite cells exhibit excellent thermal and atmospheric stability, unprecedented for Sn based perovskites. This device architecture and materials set will enable 'all perovskite' thin film solar cells to reach the highest efficiencies in the long term at the lowest costs

    Erythropoiesis-Stimulating agents in the management of anemia in chronic kidney disease or cancer: a historical perspestive.

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    Anemia is common in patients with cancer or with chronic kidney disease (CKD). Although the introduction of erythropoiesis-stimulating agents (ESAs) has transformed the management of anemia, their use has been complicated by a number of factors including frequent guideline updates, safety concerns and, in the United States, a Risk Evaluation and Mitigation Strategy (REMS) program, which aimed to ensure that the benefits of ESAs outweigh the risks. Many previous concerns around ESA use in cancer and CKD have been addressed by the reassuring results of post-approval studies, and biosimilar ESAs have been used in Europe for many years, with safety and efficacy profiles similar to originator products. This review describes the evolution of the use of ESAs from approval to the present day, discussing results from clinical studies of ESAs in cancer and CKD, and the influence of these findings on product labeling and guideline updates. We also discuss the impact of the introduction of ESA biosimilars in Europe, bringing cost savings and increased access to patients
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