646 research outputs found

    Damping of Fe-Al Alloy Electrodeposited in an Ionic Liquid

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    Iron-Aluminium alloys were produced by the electro-deposition of iron-aluminium on a copper substrate. The electro-deposition process was done in the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate, [Py1,4]TfO. A solution of (0.2 M FeCl2 + 2.75 M AlCl3)/ [Py1,4] TfO was used at a temperature of T=363 K because this mixture is solid at room temperature. Electrodeposited samples were studied by means of mechanical spectroscopy, differential thermal analysis and laser light microscopy. Mechanical spectroscopy studies were performed as a function of temperature, frequency and strain. The usual damping peaks for copper, low temperature grain boundary peak, recovery peak and intermediate temperature grain boundary peak were observed. In addition, a new damping peak at around 800 K which is not thermally activated was discovered. The physical mechanism controlling the appearance of this new peak is the dissolution of small precipitates or agglomerates of defects which take place at around 800 K during the warming and the subsequent re-precipitation/re-agglomeration during the cooling. This process could occur either in the copper substrate or at the Fe-Al electrodeposit.Fil: Lambri, Osvaldo Agustin F.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas Ingeniería y Agrimensura. Escuela de Ingeniería Eléctrica. Laboratorio de Extensión e Investigación en Materiales; ArgentinaFil: Weidenfeller, Bernd. Technische Universitat Clausthal; AlemaniaFil: Bonifacich, Federico Guillermo. Universidad Nacional de Rosario. Facultad de Ciencias Exactas Ingeniería y Agrimensura. Escuela de Ingeniería Eléctrica. Laboratorio de Extensión e Investigación en Materiales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Pulletikurthi, Giridar. Technische Universitat Clausthal; AlemaniaFil: Xu, Jiayi. Technische Universitat Clausthal; AlemaniaFil: Weidenfeller, Laura. Technische Universitat Clausthal; Alemani

    Assessing Wetland Hydroperiod and Soil Moisture With Remote Sensing: A Demonstration for the NASA Plum Brook Station Year 2

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    Primary Goal: Assist with the evaluation and measuring of wetlands hydroperiod at the PlumBrook Station using multi-source remote sensing data as part of a larger effort on projecting climate change-related impacts on the station's wetland ecosystems. MTRI expanded on the multi-source remote sensing capabilities to help estimate and measure hydroperiod and the relative soil moisture of wetlands at NASA's Plum Brook Station. Multi-source remote sensing capabilities are useful in estimating and measuring hydroperiod and relative soil moisture of wetlands. This is important as a changing regional climate has several potential risks for wetland ecosystem function. The year two analysis built on the first year of the project by acquiring and analyzing remote sensing data for additional dates and types of imagery, combined with focused field work. Five deliverables were planned and completed: 1) Show the relative length of hydroperiod using available remote sensing datasets 2) Date linked table of wetlands extent over time for all feasible non-forested wetlands 3) Utilize LIDAR data to measure topographic height above sea level of all wetlands, wetland to catchment area radio, slope of wetlands, and other useful variables 4) A demonstration of how analyzed results from multiple remote sensing data sources can help with wetlands vulnerability assessment 5) A MTRI style report summarizing year 2 results. This report serves as a descriptive summary of our completion of these our deliverables. Additionally, two formal meetings were held with Larry Liou and Amanda Sprinzl to provide project updates and receive direction on outputs. These were held on 2/26/15 and 9/17/15 at the Plum Brook Station. Principal Component Analysis (PCA) is a multivariate statistical technique used to identify dominant spatial and temporal backscatter signatures. PCA reduces the information contained in the temporal dataset to the first few new Principal Component (PC) images. Some advantages of PCA include the ability to filter out temporal autocorrelation and reduce speckle to the higher order PC images. A PCA was performed using ERDAS Imagine on a time series of PALSAR dates. Hydroperiod maps were created by separating the PALSAR dates into two date ranges, 2006-2008 and 2010, and performing an unsupervised classification on the PCAs

    Interleukin-17 as a molecular target in immune-mediated arthritis: Immunoregulatory properties of genetically modified murine dendritic cells that secrete interleukin-4

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    Objective Our previous studies have shown that murine dendritic cells (DCs) genetically modified to express interleukin-4 (IL-4) reduce the incidence and severity of murine collagen-induced arthritis. The present studies were performed to assess the immunoregulatory mechanisms underlying this response, by assessing the effects of IL-4 DCs on cytokine production by subsets of T helper cells. Methods Male DBA mice ages 6–8 weeks old were immunized with type II collagen. Splenic T cells obtained during the initiation phase and the end stage of arthritis were cultured with IL-4 DCs or untransduced DCs in the presence of collagen rechallenge. Interferon-Γ (IFNΓ) and IL-17 responses were measured. Antibodies to IL-4, IL-12, and IL-23, and recombinant IL-4, IL-12, and IL-23 were used to further study the regulation of T cell cytokine production by IL-4 DCs. Results Splenic T cells obtained during the initiation phase of arthritis produced less IL-17 when cultured in the presence of IL-4 DCs, despite their production of increased quantities of other proinflammatory cytokines (IFNΓ and tumor necrosis factor). T cell IL-17 production after collagen rechallenge was not inhibited by a lack of IL-23, since IL-4–mediated suppression of IL-17 was not reconstituted by IL-23, an otherwise potent inducer of IL-17 production by T cells. Although IL-4 DCs can produce increased quantities of IL-12 and IFNΓ, suppression of IL-17 production by IL-4 DCs was independent of both. While IL-17 production by T cells obtained during the initiation phase of arthritis was regulated by IL-4 DCs, IL-17 production by T cells obtained during end-stage arthritis was not altered. Conclusion Our data suggest that IL-4 DCs exert a therapeutic effect on collagen-induced arthritis by targeting IL-17. IL-17 suppression by IL-4 DCs is robust and is not reversed by IL-23. Timing might be important in IL-17–targeted therapy, since IL-17 production by T cells obtained during end-stage arthritis did not respond to suppression by IL-4 DCs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55925/1/22311_ftp.pd

    Plastic Packaging Waste Management in Iceland: Challenges and Opportunities from a Life Cycle Assessment Perspective

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    The management of plastic packaging waste is advancing quickly, and new strategies are being implemented worldwide for better resource recovery. To assess the environmental benefits of new ways of handling plastic packaging waste, we need to first evaluate current waste management options in order to create a basis for comparison. In this study, the environmental impacts of plastic packaging waste handling are assessed for the first time in Iceland using the life cycle assessment (LCA) methodology. The results show that mechanical recycling, despite including the impacts of exporting the waste to different European countries, has more environmental benefits than landfilling the waste in Iceland. Increasing the recycling rates of plastic waste in Iceland is also identified as a promising option from a resource efficiency perspective. With better waste sorting, Iceland can become more environmentally sustainable, ensuring that plastic materials land in recycling processes, and thereby enhancing the flow of material in the circular economy

    Identification of woodland vernal pools with seasonal change PALSAR data for habitat conservation

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    Woodland vernal pools are important, small, cryptic, ephemeral wetland ecosystems that are vulnerable to a changing climate and anthropogenic influences. To conserve woodland vernal pools for the state of Michigan USA, vernal pool detection and mapping methods were sought that would be efficient, cost-effective, repeatable and accurate. Satellite-based L-band radar data from the high (10 m) resolution Japanese ALOS PALSAR sensor were evaluated for suitability in vernal pool detection beneath forest canopies. In a two phase study, potential vernal pool (PVP) detection was first assessed with unsupervised PALSAR (LHH) two season change detection (spring when flooded—summer when dry) and validated with 268, 1 ha field-sampled test cells. This resulted in low false negatives (14%–22%), overall map accuracy of 48% to 62% and high commission error (66%). These results make this blind two-season PALSAR approach for cryptic PVP detection of use for locating areas of high vernal pool likelihood. In a second phase of the research, PALSAR was integrated with 10 m USGS DEM derivatives in a machine learning classifier, which greatly improved overall PVP map accuracies (91% to 93%). This supervised approach with PALSAR was found to produce better mapping results than using LiDAR intensity or C-band SAR data in a fusion with the USGS DEM-derivatives

    Mise en œuvre et évaluation de « I-Guide », un programme pilote de mentorat par les quasi-pairs en médecine interne

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    Implication Statement An Internal Medicine (IM) specific, near-peer mentorship program was initiated at the University of Ottawa (uOttawa) in 2017. Medical students were paired with IM resident mentors in an effort to improve career decision-making. Additionally, residents had the opportunity to formally teach mentees various high-yield IM topics. Program evaluation was completed using data from three participant cohorts, and showed that the program had a positive impact on students’ career decision making. Given the program’s flexible nature and ease of implementation, it is well suited for adaptation at other institutions.ÉnoncĂ© des implications de la recherche Un programme de mentorat par les quasi-pairs spĂ©cifique Ă  la mĂ©decine interne (MI), a Ă©tĂ© lancĂ© Ă  l’UniversitĂ© d’Ottawa en 2017. Les Ă©tudiants en mĂ©decine ont Ă©tĂ© jumelĂ©s avec des mentors rĂ©sidents en MI afin d’aider les premiers Ă  prendre des dĂ©cisions concernant leur carrière par le biais de discussions sur des sujets d’intĂ©rĂŞt pour eux. L’évaluation du programme, rĂ©alisĂ©e sur la base des donnĂ©es de trois cohortes de participants, a montrĂ© qu’il a eu un impact positif sur la prise de dĂ©cisions des Ă©tudiants Ă  propos de leur carrière. Étant donnĂ© la nature du programme et sa mise en Ĺ“uvre facile, il peut ĂŞtre adaptĂ© sans difficultĂ© au contexte d’autres Ă©tablissements

    Distinguishing the vegetation and soil component of δ13C variation in speleothem records from degassing and prior calcite precipitation effects

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    The carbon isotopic signature inherited from soil/epikarst processes may be modified by degassing and prior calcite precipitation (PCP) before its imprint on speleothem calcite. Despite laboratory demonstration of PCP effects on carbon isotopes and increasingly sophisticated models of the governing processes, to date, there has been limited effort to deconvolve the dual PCP and soil/epikarst components in measured speleothem isotopic time series. In this contribution, we explore the feasibility, advantages, and disadvantages of using trace element ratios and &delta;44Ca to remove the overprinting effect of PCP on measured &delta;13C to infer the temporal variations in the initial &delta;13C of dripwater. In 8 examined stalagmites, the most widely utilized PCP indicators Mg/Ca and &delta;44Ca covary as expected. However, Sr/Ca does not show consistent relationships with &delta;44Ca so PCP is not universally the dominant control on Sr/Ca. From &delta;44Ca and Mg/Ca, our calculation of PCP as fCa, fraction of initial Ca remaining at the deposition of the stalagmite layer, yields multiple viable solutions depending on the assumed &delta;44Ca fractionation factor and inferred variation in DMg. Uncertainty in the effective fractionation of &delta;13C during degassing and precipitation contributes to uncertainty in the absolute value of estimated initial &delta;13C. Nonetheless, the trends in initial &delta;13C are less sensitive to these uncertainties. In coeval stalagmites from the same cave spanning 94 to 82 ka interval, trends in calculated initial &delta;13C are more similar than those in measured &delta;13C, and reveal a common positive anomaly initial &delta;13C during a stadial cooling event. During deglaciations, the trend of greater respiration rates and higher soil CO2 is captured in the calculated initial &delta;13C, despite the tendency of higher interglacial dripwater situation to favor more extensive PCP.</p

    Long-Term Resveratrol Supplementation as a Secondary Prophylaxis for Stroke

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    Stroke is a leading cause of mortality worldwide, as well as a source of long-term disabilities and huge socioeconomic costs. This study investigates the effects of resveratrol, an antioxidant supplement, on blood pressure, weight status, glucose, and lipid profile in patients who had a stroke in the last 12 months. Two hundred and twenty-eight patients were divided into three groups: group I received only allopathic treatment (control group), while groups II and III received allopathic treatment with a daily supplementation of oral resveratrol (100 and 200 mg, resp.) for 12 months. In all groups, the changes of the studied parameters were monitored at 6 and 12 months from the initial evaluation. In groups II and III, resveratrol induced significant changes (p<0.05) in the blood pressure, body mass index, as well as all parameters of the lipid profile, and glucose (in nondiabetic patients), compared to the control group. The supplementation of the allopathic treatment with resveratrol had a beneficial effect on all monitored parameters, which serve as major risk factors for stroke

    Regulation of pathogenic IL-17 responses in collagen-induced arthritis: roles of endogenous interferon-gamma and IL-4

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    Abstract Introduction Interleukin (IL)-17 plays an important role in the pathogenesis of rheumatoid arthritis and the mouse model collagen-induced arthritis (CIA). Interferon(IFN)-Îł and IL-4 have been shown to suppress Th17 development in vitro, but their potential immunoregulatory roles in vivo are uncertain. The goals of this study were to determine the relationship between Th17 responses and disease severity in CIA and to assess regulation of IL-17 by endogenous IFN-Îł and IL-4. Methods DBA1/LacJ mice were immunized with type II collagen in complete Freund's adjuvant (CFA) to induce arthritis, and treated with neutralizing antibody to IFN-Îł and/or IL-4. Systemic IL-17, IFN-Îł, and IL-4 were measured in serum. At the peak of disease, cytokine production was measured by ELISA of supernatants from spleen, lymph node and paw cultures. Paws were also scored for histologic severity of arthritis. Results Joint inflammation was associated with a higher ratio of systemic IL-17/IFN-Îł. Neutralization of IFN-Îł accelerated the course of CIA and was associated with increased IL-17 levels in the serum and joints. The IFN-Îł/IL-4/IL-17 responses in the lymphoid organ were distinct from such responses in the joints. Neutralization of IL-4 led to increased arthritis only in the absence of IFN-Îł and was associated with increased bone and cartilage damage without an increase in the levels of IL-17. Conclusions IL-4 and IFN-Îł both play protective roles in CIA, but through different mechanisms. Our data suggests that the absolute level of IL-17 is not the only determinant of joint inflammation. Instead, the balance of Th1, Th2 and Th17 cytokines control the immune events leading to joint inflammation.http://deepblue.lib.umich.edu/bitstream/2027.42/112787/1/13075_2009_Article_2675.pd
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