6,365 research outputs found

    Surface-Plasmon-Assisted Photoelectrochemical Reduction of CO2 and NO3− on Nanostructured Silver Electrodes

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    Electrochemical reduction of carbon dioxide (CO2) typically suffers from low selectivity and poor reaction rates that necessitate high overpotentials, which impede its possible application for CO2 capture, sequestration, or carbon-based fuel production. New strategies to address these issues include the utilization of photoexcited charge carriers to overcome activation barriers for reactions that produce desirable products. This study demonstrates surface-plasmon-enhanced photoelectrochemical reduction of CO2 and nitrate (NO3−) on silver nanostructured electrodes. The observed photocurrent likely originates from a resonant charge transfer between the photogenerated plasmonic hot electrons and the lowest unoccupied molecular orbital (MO) acceptor energy levels of adsorbed CO2, NO3−, or their reductive intermediates. The observed differences in the resonant effects at the Ag electrode with respect to electrode potential and photon energy for CO2 versus NO3− reduction suggest that plasmonic hot-carriers interact selectively with specific MO acceptor energy levels of adsorbed surface species such as CO2, NO3−, or their reductive intermediates. This unique plasmon-assisted charge generation and transfer mechanism can be used to increase yield, efficiency, and selectivity of various photoelectrochemical processes

    Stroke risk among patients with chronic obstructive pulmonary disease: A systematic review and meta-analysis

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    Increased stroke risk among chronic obstructive pulmonary disease patients has not yet been established. In this study, we conducted a systematic review and meta-analysis to assess stroke risk among chronic obstructive pulmonary disease patients. PubMed, EMBASE, and the Cochrane Library were systematically searched from database inception until December 31, 2016 to identify longitudinal observational studies that investigated the association between chronic obstructive pulmonary disease and stroke. Stroke risk was quantified by overall and subgroup analyses, and a pooled hazard ratio was calculated. Study quality was evaluated using the Newcastle-Ottawa Scale. Publication bias was assessed using Begg’s rank correlation test. Eight studies met the inclusion criteria. In a random-effects model, significantly increased stroke risk was observed among chronic obstructive pulmonary disease patients (hazard ratio, 1.30; 95% confidence interval, 1.18-1.43). In subgroup analyses stratified by stroke subtype, study quality, and adjustment by socioeconomic status, the association between increased stroke risk and chronic obstructive pulmonary disease patients was robust. Statistically significant publication bias was not detected. In summary, chronic obstructive pulmonary disease was found to be associated with increased stroke risk. Additional prospective studies are required to elucidate the mechanisms underlying the increase in stroke risk and identify effective preventive interventions

    Use of archival versus newly collected tumor samples for assessing PD-L1 expression and overall survival : an updated analysis of KEYNOTE-010 trial

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    Background: In KEYNOTE-010, pembrolizumab versus docetaxel improved overall survival (OS) in patients with programmed death-1 protein (PD)-L1-positive advanced non-small-cell lung cancer (NSCLC). A prespecified exploratory analysis compared outcomes in patients based on PD-L1 expression in archival versus newly collected tumor samples using recently updated survival data. Patients and methods: PD-L1 was assessed centrally by immunohistochemistry (22C3 antibody) in archival or newly collected tumor samples. Patients received pembrolizumab 2 or 10 mg/kg Q3W or docetaxel 75 mg/m2 Q3W for 24 months or until progression/intolerable toxicity/other reason. Response was assessed by RECIST v1.1 every 9 weeks, survival every 2 months. Primary end points were OS and progression-free survival (PFS) in tumor proportion score (TPS) 50% and 1%; pembrolizumab doses were pooled in this analysis. Results: At date cut-off of 24 March 2017, median follow-up was 31 months (range 23-41) representing 18 additional months of follow-up from the primary analysis. Pembrolizumab versus docetaxel continued to improve OS in patients with previously treated, PD-L1-expressing advanced NSCLC; hazard ratio (HR) was 0.66 [95% confidence interval (CI): 0.57, 0.77]. Of 1033 patients analyzed, 455(44%) were enrolled based on archival samples and 578 (56%) on newly collected tumor samples. Approximately 40% of archival samples and 45% of newly collected tumor samples were PD-L1 TPS 50%. For TPS 50%, the OS HRs were 0.64 (95% CI: 0.45, 0.91) and 0.40 (95% CI: 0.28, 0.56) for archival and newly collected samples, respectively. In patients with TPS 1%, OS HRs were 0.74 (95% CI: 0.59, 0.93) and 0.59 (95% CI: 0.48, 0.73) for archival and newly collected samples, respectively. In TPS 50%, PFS HRs were similar across archival [0.63 (95% CI: 0.45, 0.89)] and newly collected samples [0.53 (95% CI: 0.38, 0.72)]. In patients with TPS 1%, PFS HRs were similar across archival [0.82 (95% CI: 0.66, 1.02)] and newly collected samples [0.83 (95% CI: 0.68, 1.02)]. Conclusion: Pembrolizumab continued to improve OS over docetaxel in intention to treat population and in subsets of patients with newly collected and archival samples

    An Inflammatory Fibroid Polyp in the Hepatic Flexure of the Colon Treated with Argon Plasma Coagulation, Endoscopic Clipping and Polypectomy

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    Inflammatory fibroid polyp (IFP) is a rare benign polypoid lesion of the gastrointestinal tract. Most IFPs occur in the stomach and colonic occurrence is very rare. Histologically IFP is characterized by a mixture of numerous small vessels, fibroblasts and edematous connective tissue associated with marked inflammatory infiltration by eosinophils. We present a rare case of a pedunculated IFP in the hepatic flexure of the colon treated successfully with a combination of argon plasma coagulation, endoclipping and polypectomy. A 74-year-old asymptomatic female underwent a screening colonoscopy in our hospital. A 12-mm pedunculated polyp was found at the hepatic flexure of the colon. After saline injection, we attempted to remove the polyp with a hot snare. However the polyp stalk was extremely difficult to resect despite several attempts with the hot snare. We placed an endoclip at the base of the stalk and then applied argon plasma coagulation at 1.0 l/min and 40 W. After these measures we were able to resect the stalk and the polyp was retrieved. Histologically the polyp was located in the submucosa of the gastrointestinal tract. Proliferation of spindle cells and infiltration of inflammatory cells such as plasma cells and eosinophils were observed. The spindle cells were positive for CD34 and S100 but negative for c-kit and muscle markers. These findings are consistent with a histopathological diagnosis of IFP

    Advanced micro and nano manufacturing technologies used in medical domain

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    This paper focuses on the aspects of advanced manufacturing technologies, namely micro and nano manufacturing (MNM) capabilities which are particularly relevant to medical domain. In recent years, the so called disruptive technologies have enabled engineers and clinicians to collaborate in solving complex problems which require advanced MNM capabilities to develop medical applications. As a result what was nearly impossible a few years ago, due to limitations in machining and manufacturability of micro and nano scale artefacts, are now made possible thanks to innovative manufacturing processes and technologies. The potential medical applications of the new MNM methods are immense and in this paper four potential uses, namely as medical devices, lab on chips, and brain implants are presented and discussed. These works were based on different projects undertaken by researchers at Cardiff University, UK. The manufacturing costs, though initially high, are expected to reduce over time as the technologies mature and become more widely available. Introducing these MNM technologies and disseminating these results to healthcare engineering, for a better quality of medical diagnosis and treatments with cost-effective solutions, will greatly benefit the majority of population who live in the developing countries in receiving appropriate and affordable medical care to achieve improvements in their quality of life

    Resonance Raman scattering studies in Br-2-adsorbed double-wall carbon nanotubes

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    ArticlePhysical Review B. 73(23):235413 (2006)journal articl
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