385 research outputs found

    Design of Eco-Efficient Body Parts for Electric Vehicles Considering Life Cycle Environmental Information

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    The reduction of greenhouse gas (GHG) emissions over the entire life cycle of vehicles has become part of the strategic objectives in automotive industry. In this regard, the design of future body parts should be carried out based on information of life cycle GHG emissions. The substitution of steel towards lightweight materials is a major trend, with the industry undergoing a fundamental shift towards the introduction of electric vehicles (EV). The present research aims to support the conceptual design of body parts with a combined perspective on mechanical performance and life cycle GHG emissions. Particular attention is paid to the fact that the GHG impact of EV in the use phase depends on vehicle-specific factors that may not be specified at the conceptual design stage of components, such as the market-specific electricity mix used for vehicle charging. A methodology is proposed that combines a simplified numerical design of concept alternatives and an analytic approach estimating life cycle GHG emissions. It is applied to a case study in body part design based on a set of principal geometries and load cases, a range of materials (aluminum, glass and carbon fiber reinforced plastics (GFRP, CFRP) as substitution to a steel reference) and different use stage scenarios of EV. A new engineering chart was developed, which helps design engineers to compare life cycle GHG emissions of lightweight material concepts to the reference. For body shells, the replacement of the steel reference with aluminum or GFRP shows reduced lifecycle GHG emissions for most use phase scenarios. This holds as well for structural parts being designed on torsional stiffness. For structural parts designed on tension/compression or bending stiffness CFRP designs show lowest lifecycle GHG emissions. In all cases, a high share of renewable electricity mix and a short lifetime pose the steel reference in favor. It is argued that a further elaboration of the approach could substantially increase transparency between design choices and life cycle GHG emissions

    External beam radiation after stent implantation increases neointimal hyperplasia by augmenting smooth muscle cell proliferation and extracellular matrix accumulation

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    AbstractOBJECTIVESWe sought to examine the effects of high volume external beam radiation (EBR) after stent implantation on neointimal hyperplasia, smooth muscle cell (SMC) proliferation, presence of inflammatory cells and expression of extracellular matrix (ECM).BACKGROUNDEndovascular irradiation has been shown to reduce restenosis rates after angioplasty in preliminary trials, but conflicting results have been reported for the effects of external beam irradiation.METHODSForty-three Palmaz-Schatz stents were implanted into iliac arteries of New Zealand White rabbits. The arteries were externally irradiated after stent implantation with a single dose of 8 Gy (at day 3) or 16 Gy in two fractions (8 Gy at days 3 and 4) by means of a linear accelerator. In the control rabbits, no radiation was applied after stent implantation. Smooth muscle cells, macrophages and ECM were studied by immunohistochemistry at one and 12 weeks after stent implantation. Collagen type I and biglycan messenger ribonucleic acid (mRNA) levels were assessed by Northern blot analysis at one week. Neointimal cell densities and arterial lumen stenosis were measured by histomorphometry at 12 weeks.RESULTSAt 1 week, SMC proliferation at the site of stent implantation was increased after EBR with 8 and 16 Gy (26 ± 5%, 32 ± 3% vs. 17 ± 8%; p < 0.01, 16 Gy vs. control). External beam radiation with 8 and 16 Gy augmented SMC proliferation proximal and distal to the angioplasty site (11 ± 3%, 14 ± 3 vs. 6 ± 1%; p < 0.01, 16 Gy vs. control). Collagen type I and biglycan mRNA levels were elevated in stented arteries after EBR with 16 Gy. At 12 weeks, a marked decrease in neointimal cell density (248 ± 97 vs. 498 ± 117 SMCs/0.1 mm2neointima; p < 0.005 vs. control) was noted after EBR with 16 Gy. Irradiation with 8 and 16 Gy increased arterial lumen stenosis compared with nonirradiated control rabbits (45 ± 7%, 55 ± 9% vs. 33 ± 7%; p < 0.05, 8 Gy and p < 0.001, 16 Gy vs. control).CONCLUSIONSHigh volume external beam radiation at doses of 8 or 16 Gy causes restenosis by augmenting proliferative activity at and adjacent to the site of stent implantation, and by dose-dependent up-regulation of extracellular matrix expression. The study suggests that excessive matrix accumulation is an important determinant of failure of radiation therapy to prevent restenosis

    Effects of Psychiatric Comorbidity on Treatment Outcome in Patients Undergoing Diamorphine or Methadone Maintenance Treatment

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    Background: Comorbid psychiatric disorders among opioid-dependent patients are associated with several negative outcome factors. However, outcomes of maintenance treatment have not been sufficiently established, and no evidence is available with respect to heroin-assisted treatment (HAT). Methods: For patients in the German heroin trial outcome measures were analyzed for HAT versus methadone maintenance treatment (MMT) both for patients with and without a comorbid diagnosis according to CIDI. Results: 47.2% of the sample had at least one comorbid psychiatric diagnosis, mainly neurotic, stress-related or somatoform (F4) or affective (F3) disorders. HAT had a better outcome than MMT concerning improvement of health and reduction of illicit drug use in both comorbid and non-comorbid patients, but weaker effects were found in the comorbid group. Conclusions:The better outcome of HAT also in comorbid patients suggests that psychiatric comorbidity should be an inclusion criterion for HAT. The weaker advantage of HAT may be due to pharmacological or methodological reasons

    Effects of heroin-assisted treatment on alcohol consumption: findings of the German randomized controlled trial

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    Alcohol has been suggested to be a risk factor for opioid-dependent patients in methadone maintenance treatment (MMT). Literature shows that MMT has limited effects on alcohol use. Nevertheless, a decrease in alcohol use was detected in the Swiss heroin-assisted treatment (HAT) study. In this article, we carry out an in-depth analysis of the German HAT trial with the aim of determining whether alcohol use was affected among patients undergoing HAT and MMT. Analysis was carried out using self-reported data on consumption units of alcohol used (CU), Addiction Severity Index composite scores (ASI CSs), and carbohydrate-deficient transferrin (CDT) measures. Results suggest significant reduction of CU and CDT in both groups, yet larger effects in the HAT group. ASI CS significantly decreased in the HAT but not in the MMT group. The greater benefit of HAT in reducing alcohol use may be due to the greater daily frequency of dispensing heroin coupled with a requirement of sobriety at each dosing occasion

    Focused didactic training for skills lab student tutors – which techniques are considered helpful?

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    Objective: Peer-assisted learning is widely used in medical education. However, little is known about an appropriate didactic preparation for peer tutors. We herein describe the development of a focused didactic training for skills lab tutors in Internal Medicine and report on a retrospective survey about the student tutors’ acceptance and the perceived transferability of attended didactic training modules

    TOWARDS CROSS-ORGANISATIONAL E-GOVERNMENT: AN INTEGRATED APPROACH

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    One of the most challenging issues in current e-Government initiatives is the seamless exchange of information and the efficient collaboration between public administrations, companies and the private sector. Either from an intra- or cross-organisational point of view spanning processes across multiple authorities leads to a collaboration of autonomous units under consideration of law and regulations. Despite the organisational dimension current approaches are mainly technical solutions – e.g. interoperability frameworks. Within this paper we present an integrated approach which incorporates organisational aspects of the public sector and which supports the correspondent implementation of solutions for cross-organisational e-Government by adopting Model-Driven-Development practices

    Prepackaged central line kits reduce procedural mistakes during central line insertion: a randomized controlled prospective trial

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    BACKGROUND: Central line catheter insertion is a complex procedure with a high cognitive load for novices. Providing a prepackaged all-inclusive kit is a simple measure that may reduce the cognitive load. We assessed whether the use of prepackaged all-inclusive central line insertion kits reduces procedural mistakes during central line catheter insertion by novices. METHODS: Thirty final year medical students and recently qualified physicians were randomized into two equal groups. One group used a prepackaged all-inclusive kit and the other used a standard kit containing only the central vein catheter and all other separately packaged components provided in a materials cart. The procedure was videotaped and analyzed by two blinded raters using a checklist. Both groups performed central line catheter insertion on a manikin, assisted by nursing students. RESULTS: The prepackaged kit group outperformed the standard kit group in four of the five quality indicators: procedure duration (26:26 ± 3:50 min vs. 31:27 ± 5:57 min, p = .01); major technical mistakes (3.1 ± 1.4 vs. 4.8 ± 2.6, p = .03); minor technical mistakes (5.2 ± 1.7 vs. 8.0 ± 3.2, p = .01); and correct steps (83 ± 5% vs. 75 ± 11%, p = .02). The difference for breaches of aseptic technique (1.2 ± 0.8 vs. 3.0 ± 3.6, p = .06) was not statistically significant. CONCLUSIONS: Prepackaged all-inclusive kits for novices improved the procedure quality and saved staff time resources in a controlled simulation environment. Future studies are needed to address whether central line kits also improve patient safety in hospital settings

    Investigations on the Usefulness of CEACAMs as Potential Imaging Targets for Molecular Imaging Purposes

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    Members of the carcinoembryonic antigen cell adhesion molecules (CEACAMs) family are the prototype of tumour markers. Classically they are used as serum markers, however, CEACAMs could serve as targets for molecular imaging as well. In order to test the anti CEACAM monoclonal antibody T84.1 for imaging purposes, CEACAM expression was analysed using this antibody. Twelve human cancer cell lines from different entities were screened for their CEACAM expression using qPCR, Western Blot and FACS analysis. In addition, CEACAM expression was analyzed in primary tumour xenografts of these cells. Nine of 12 tumour cell lines expressed CEACAM mRNA and protein when grown in vitro. Pancreatic and colon cancer cell lines showed the highest expression levels with good correlation of mRNA and protein level. However, when grown in vivo, the CEACAM expression was generally downregulated except for the melanoma cell lines. As the CEACAM expression showed pronounced expression in FemX-1 primary tumours, this model system was used for further experiments. As the accessibility of the antibody after i.v. application is critical for its use in molecular imaging, the binding of the T84.1 monoclonal antibody was assessed after i.v. injection into SCID mice harbouring a FemX-1 primary tumour. When applied i.v., the CEACAM specific T84.1 antibody bound to tumour cells in the vicinity of blood vessels. This binding pattern was particularly pronounced in the periphery of the tumour xenograft, however, some antibody binding was also observed in the central areas of the tumour around blood vessels. Still, a general penetration of the tumour by i.v. application of the anti CEACAM antibody could not be achieved despite homogenous CEACAM expression of all melanoma cells when analysed in tissue sections. This lack of penetration is probably due to the increased interstitial fluid pressure in tumours caused by the absence of functional lymphatic vessels.Germany. Bundesministerium für Bildung und Forschung (TOMCAT, grant number 01EZ0824
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