1,482 research outputs found

    Glow Discharge Optical Emission Spectrometry (GDOES), an Effectiveness Method for Characterizing Composition of Surfaces and Coatings

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    Within the frame of this work, the technical procedures and real advantages of using Glow Discharge Optical Emission Spectroscopy (GDOES) for establishing depth concentration profiles of surfaces are presented. GDOES can detect low concentrations with high accuracy. It can be used for either quantitative bulk analysis (QBA) or quantitative depth profiling (QDP) in the nanometer to micron range. Non-conductive and conductive samples can be analysed. The main applications of this spectral method are related to different technology fields such as: heat treatment processes, casting, heat and cold forming processes, thermochemical treatments, electro-chemical processes (galvanic coatings), chemical and physical vapour depositions (CVD, PVD), thermal oxidation processes and anodizing, thin-films and others

    Online self-assessments to measure study-related competencies

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    An der UniversitĂ€t Frankfurt entwickelte Online-Self-Assessment-Verfahren fĂŒr die StudiengĂ€nge Psychologie und Informatik sollen Studieninteressierten noch vor Studienbeginn auf der Basis von Selbsterkundungsmaßnahmen und Tests eine RĂŒckmeldung ĂŒber ihre eigenen FĂ€higkeiten, Motive, personalen Kompetenzen und Interessen mit Blick auf den jeweiligen Studiengang geben. Sowohl die Befunde zur psychometrischen GĂŒte der Verfahren als auch jene zur prognostischen ValiditĂ€t lassen ihren Einsatz zur Feststellung studienrelevanter Kompetenzen als geeignet erscheinen. Da die erfassten Kompetenzen und Merkmale substanzielle Beziehun-gen zu Studienleistungen aufweisen, könnten die Informationen ĂŒber individuelle StĂ€rken zur Wahl eines geeigneten Studienganges genutzt werden; SchwĂ€chen hingegen könnten frĂŒhzeitig Hinweise fĂŒr geeignete Fördermaßnahmen liefern.Online self-assessments are offered as a means to inform prospective students about their personal appropriateness in the degree programs of psychology and computer science at the University of Frankfurt. Based on online tests a feedback regarding their skills, motives, personal competencies and orientations with respect to the particular study course is provided. Psychometric properties and predictive validity suggest the suitability as an instrument to assess study-related competencies. Since the measures applied as part of the study show substantial relationships to course achievement, one could utilize the Self-Assessments information for decisions concerning the selection of an appropriate course of studies. Furthermore, noted weaknesses could serve as early hints for appropriate affirmative actions

    Limb sounders tracking topographic gravity wave activity from the stratosphere to the ionosphere around midlatitude Andes

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    Several studies have shown that the surroundings of the highest Andes mountains at midlatitudes in the Southern Hemisphere exhibit gravity waves (GWs) generated by diverse sources which may traverse the troposphere and then penetrate the upper layers if conditions are favorable. There is a specific latitude band where that mountain range is nearly perfectly aligned with the north‐south direction, which favors the generation of wavefronts parallel to this orientation. This fact may allow an optimization of procedures to identify topographic GW in some of the observations. We analyze data per season to the east and west of these Andes latitudes to find possible significant differences in GW activity between both sectors. GW effects generated by topography and convection are expected essentially on the eastern side. We use satellite data from two different limb sounding methods: the Global Positioning System radio occultation (RO) technique and the Sounding of the Atmosphere using Broadband Emission Radiometry instrument, which are complementary with respect to the height intervals, in order to study the effects of GW from the stratosphere to the ionosphere. Activity becomes quantified by the GW average potential energy in the stratosphere and mesosphere and by the electron density variance content in the ionosphere. Consistent larger GW activity on the eastern sector is observed from the stratosphere to the ionosphere (night values). However, this fact remains statistically significant at the 90% significance level only during winter, when GWs generated by topography dominate the eastern sector. On the contrary, it is usually assumed that orographic GWs have nearly zero horizontal phase speed and will therefore probably be filtered at some height in the neutral atmosphere. However, this scheme relies on the assumption that the wind is uniform and constant. Our results also suggest that it is advisable to separate night and day cases to study GWs in the ionosphere, as it is more difficult to find significant statistical differences during daytime. This may happen because perturbations induced by GWs during daytime are more likely to occur in a disturbed environment that may hinder the identification of the waves.Fil: Alexander, Pedro Manfredo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de FĂ­sica de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de FĂ­sica de Buenos Aires; ArgentinaFil: de la Torre, Alejandro. Universidad Austral. Facultad de IngenierĂ­a; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Schmidt, T.. German Research Centre for Geosciences; AlemaniaFil: Llamedo Soria, Pablo Martin. Universidad Austral. Facultad de IngenierĂ­a; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Hierro, Rodrigo Federico. Universidad Austral. Facultad de IngenierĂ­a; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentin

    Lifestyle factors associated with inflammatory bowel disease: data from the Swiss IBD cohort study.

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    BACKGROUND Various environmental risk factors have been associated with the pathogenesis of inflammatory bowel disease. In this study we aimed to identify lifestyle factors that affect the onset of Crohn's disease and ulcerative colitis. METHODS 2294 patients from the Swiss IBD Cohort Study received a questionnaire regarding physical activity, nutritional habits and status of weight. In addition, a control group was formed comprising patients' childhood friends, who grew up in a similar environment. RESULTS Overall, 1111 questionnaires were returned (response rate: 48.4%). Significantly more patients with inflammatory bowel disease reported no regular practice of sport during childhood and beginning of adulthood compared to the control group (p = 0.0001). No association between intake of refined sugar and onset of inflammatory bowel disease was observed. More patients with Crohn's disease compared to ulcerative colitis and controls suffered from overweight during childhood (12.8% vs. 7.7% and 9.7%, respectively; p = 0.027). CONCLUSIONS Our study underlines the relevance of environmental factors in the development of inflammatory bowel disease. Our results imply a protective effect of physical activity regarding the onset of inflammatory bowel disease

    Lifestyle factors associated with inflammatory bowel disease: data from the Swiss IBD cohort study

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    BACKGROUND: Various environmental risk factors have been associated with the pathogenesis of inflammatory bowel disease. In this study we aimed to identify lifestyle factors that affect the onset of Crohn's disease and ulcerative colitis. METHODS: 2294 patients from the Swiss IBD Cohort Study received a questionnaire regarding physical activity, nutritional habits and status of weight. In addition, a control group was formed comprising patients' childhood friends, who grew up in a similar environment. RESULTS: Overall, 1111 questionnaires were returned (response rate: 48.4%). Significantly more patients with inflammatory bowel disease reported no regular practice of sport during childhood and beginning of adulthood compared to the control group (p = 0.0001). No association between intake of refined sugar and onset of inflammatory bowel disease was observed. More patients with Crohn's disease compared to ulcerative colitis and controls suffered from overweight during childhood (12.8% vs. 7.7% and 9.7%, respectively; p = 0.027). CONCLUSIONS: Our study underlines the relevance of environmental factors in the development of inflammatory bowel disease. Our results imply a protective effect of physical activity regarding the onset of inflammatory bowel disease

    Online-Self-Assessments zur Erfassung studienrelevanter Kompetenzen

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    An der UniversitĂ€t Frankfurt entwickelte Online-Self-Assessment-Verfahren fĂŒr die StudiengĂ€nge Psychologie und Informatik sollen Studieninteressierten noch vor Studienbeginn auf der Basis von Selbsterkundungsmaßnahmen und Tests eine RĂŒckmeldung ĂŒber ihre eigenen FĂ€higkeiten, Motive, personalen Kompetenzen und Interessen mit Blick auf den jeweiligen Studiengang geben. Sowohl die Befunde zur psychometrischen GĂŒte der Verfahren als auch jene zur prognostischen ValiditĂ€t lassen ihren Einsatz zur Feststellung studienrelevanter Kompetenzen als geeignet erscheinen. Da die erfassten Kompetenzen und Merkmale substanzielle Beziehungen zu Studienleistungen aufweisen, könnten die Informationen ĂŒber individuelle StĂ€rken zur Wahl eines geeigneten Studienganges genutzt werden; SchwĂ€chen hingegen könnten frĂŒhzeitig Hinweise fĂŒr geeignete Fördermaßnahmen liefern. 04.08.2009 | Siegbert Reiss, Alexander Tillmann, Michael Schreiner, Karl Schweizer, Detlef Krömker & Helfried Moosbrugger (Frankfurt am Main

    Fumarate Hydratase Loss Causes Combined Respiratory Chain Defects.

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    Fumarate hydratase (FH) is an enzyme of the tricarboxylic acid (TCA) cycle mutated in hereditary and sporadic cancers. Despite recent advances in understanding its role in tumorigenesis, the effects of FH loss on mitochondrial metabolism are still unclear. Here, we used mouse and human cell lines to assess mitochondrial function of FH-deficient cells. We found that human and mouse FH-deficient cells exhibit decreased respiration, accompanied by a varying degree of dysfunction of respiratory chain (RC) complex I and II. Moreover, we show that fumarate induces succination of key components of the iron-sulfur cluster biogenesis family of proteins, leading to defects in the biogenesis of iron-sulfur clusters that affect complex I function. We also demonstrate that suppression of complex II activity is caused by product inhibition due to fumarate accumulation. Overall, our work provides evidence that the loss of a single TCA cycle enzyme is sufficient to cause combined RC activity dysfunction

    Similar recovery time of microbial functions from fungicide stress across biogeographical regions

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    Abstract Determining whether the structural and functional stress responses of communities are similar across space and time is paramount for forecasting and extrapolating the consequences of anthropogenic pressures on ecosystems and their services. Stream ecosystems are under high anthropogenic pressure; however, studies have only examined the response of stream communities across large scales over multiple generations. We studied the responses of leaf-associated microbial communities in streams within three European biogeographical regions to chemical stress in a microcosm experiment with multiple cycles of fungicide pollution and resource colonisation. Fungal community composition and the ecosystem function leaf decomposition were measured as response variables. Microbial leaf decomposition showed similar recovery times under environmental levels of fungicide exposure across regions. Initially, the decomposition declined (between 19 and 53%) under fungicide stress and recovered to control levels during the third cycle of pollution and colonisation. Although community composition and its stress response varied between regions, this suggests similar functional community adaptation towards fungicide stress over time. Genetic, epigenetic and physiological adaptations, as well as species turnover, may have contributed to community adaptation but further studies are required to determine if and to which extent these mechanisms are operating. Overall, our findings provide the first evidence of a similar functional response of microbial leaf decomposition to chemical stress across space and time

    Vaccination with Mage-3a1 Peptide–Pulsed Mature, Monocyte-Derived Dendritic Cells Expands Specific Cytotoxic T Cells and Induces Regression of Some Metastases in Advanced Stage IV Melanoma

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    Dendritic cells (DCs) are considered to be promising adjuvants for inducing immunity to cancer. We used mature, monocyte-derived DCs to elicit resistance to malignant melanoma. The DCs were pulsed with Mage-3A1 tumor peptide and a recall antigen, tetanus toxoid or tuberculin. 11 far advanced stage IV melanoma patients, who were progressive despite standard chemotherapy, received five DC vaccinations at 14-d intervals. The first three vaccinations were administered into the skin, 3 × 106 DCs each subcutaneously and intradermally, followed by two intravenous injections of 6 × 106 and 12 × 106 DCs, respectively. Only minor (less than or equal to grade II) side effects were observed. Immunity to the recall antigen was boosted. Significant expansions of Mage-3A1–specific CD8+ cytotoxic T lymphocyte (CTL) precursors were induced in 8/11 patients. Curiously, these immune responses often declined after the intravenous vaccinations. Regressions of individual metastases (skin, lymph node, lung, and liver) were evident in 6/11 patients. Resolution of skin metastases in two of the patients was accompanied by erythema and CD8+ T cell infiltration, whereas nonregressing lesions lacked CD8+ T cells as well as Mage-3 mRNA expression. This study proves the principle that DC “vaccines” can frequently expand tumor-specific CTLs and elicit regressions even in advanced cancer and, in addition, provides evidence for an active CD8+ CTL–tumor cell interaction in situ as well as escape by lack of tumor antigen expression
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