2,212 research outputs found

    The Current Density Distribution in a Segmented-in-Series SOFC,”

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    A common tubular solid oxide fuel cell (SOFC) design consists of segmented-in-serie

    A lung-inspired approach to scalable and robust fuel cell design

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    A lung-inspired approach is employed to overcome reactant homogeneity issues in polymer electrolyte fuel cells. The fractal geometry of the lung is used as the model to design flow-fields of different branching generations, resulting in uniform reactant distribution across the electrodes and minimum entropy production of the whole system. 3D printed, lung-inspired flow field based PEFCs with N = 4 generations outperform the conventional serpentine flow field designs at 50% and 75% RH, exhibiting a 20% and 30% increase in performance (at current densities higher than 0.8 A cm2) and maximum power density, respectively. In terms of pressure drop, fractal flow-fields with N = 3 and 4 generations demonstrate 75% and 50% lower values than conventional serpentine flow-field design for all RH tested, reducing the power requirements for pressurization and recirculation of the reactants. The positive effect of uniform reactant distribution is pronounced under extended current-hold measurements, where lung-inspired flow field based PEFCs with N = 4 generations exhibit the lowest voltage decay (B5 mV h1). The enhanced fuel cell performance and low pressure drop values of fractal flow field design are preserved at large scale (25 cm2), in which the excessive pressure drop of a large-scale serpentine flow field renders its use prohibitive

    Water and sewage disposal for farm homes

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    March, 1939

    Dipeptidyl-peptidase-4 inhibitors and pancreatic cancer: a cohort study

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    Aims—Dipeptidyl-peptidase-4 inhibitors (DPP-4i) have been implicated with an increased pancreatic cancer risk. We therefore compared pancreatic cancer incidence and diagnostic work-up among initiators of DPP-4i versus sulfonylureas (SU) and thiazolidinediones (TZD). Methods—Medicare claims data were examined in a new-user active-comparator cohort study. Patients >65 years with no prescriptions for DPP-4i, SU or TZD at baseline were included if they had at least two claims for the same drug within 180 days. Using an as-treated approach and propensity score-adjusted Cox models, we estimated hazard ratios (HR) and 95% confidence intervals (CI) for pancreatic cancer. Diagnostic work-up was compared using risk ratios (RR). RESULTS—In the DPP-4i vs SU comparison, there were 18,179 DPP4i initiators of which 26 developed pancreatic cancer (follow-up time interquartile range 5–18 months). In the DPP-4i vs TZD comparison there were 29,366 DPP-4i initiators and 52 developed pancreatic cancer. The hazard of pancreatic cancer with DPP-4i was lower relative to SU (HR=0.6, CI 0.4–0.9) and similar to TZD (HR=1.0, CI 0.7–1.4). Excluding first 6 months of follow-up to reduce the potential for reverse causality did not alter results. Probability of diagnostic work-up post-initiation among DPP-4i initiators (79.3%) was similar to TZD (74.1%) (RR=1.06, CI 1.05–1.07) and SU (74.6%) (RR=1.06, CI1.05–1.07). The probability of diagnostic workup pre-index was ~80% for all cohorts. Conclusion—Though limited by sample size and the observed duration of treatment in the US, our well-controlled population based study suggests no increased short-term pancreatic cancer risk with DPP-4i relative to SU or TZD

    A Study of Metallic Corrosion Using a Surface Acoustic Wave Sensor

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    The SAW corrosion sensor has many potential applications in both mechanical and electrical systems. For example, it could be used to monitor the corrosion of electrical contacts found in power systems. An early detection device would allow for preventive actions in order to avoid the high cost of down time or equipment damage that can result from electrical failures. The SAW sensor could also be used in mechanical systems, such as aircrafts, automobiles and spacecraft to continuously monitor the corrosive activity and determine when structural elements may need to be replaced.</p

    A qualitative study of Parent to Parent support for parents of children with special needs. Consortium to evaluate Parent to Parent.

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    OBJECTIVE: To examine qualitatively the experiences of parents participating in Parent to Parent programs. METHOD: Twenty-four parents of children with special needs, a subset of subjects in a larger quantitative study, participated in a semi-structured telephone interview to explore the impact and meaning of being matched with a trained supporting parent. RESULTS: Qualitative analysis reveals a successful match is contingent upon creation of a reliable ally in the supporting parent, comprised of four main components: (1) perceived sameness, (2) situational comparisons that enable learning and growth, (3) round-the-clock availability of support, and (4) mutuality of support. CONCLUSIONS: Parent to Parent support creates a community of similar others trained to listen and be supportive and provides an opportunity for matched parents to experience equality and mutuality in their relationship. Findings also identify the need for quality control in Parent to Parent programs and the importance of such programs as an adjunct to traditional professional services

    A KRAB/KAP1-miRNA Cascade Regulates Erythropoiesis Through Stage-Specific Control of Mitophagy

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    During hematopoiesis, lineage- and stage-specific transcription factors work in concert with chromatin modifiers to direct the differentiation of all blood cells. We explored the role of KRAB-containing zinc finger proteins (KRAB-ZFPs) and their cofactor KAP1 in this process. In mice, hematopoietic-restricted deletion of Kap1 resulted in severe hypoproliferative anemia. Kap1-deleted erythroblasts failed to induce mitophagy-associated genes and retained mitochondria. This was due to persistent expression of microRNAs (miRNAs) targeting mitophagy transcripts, itself secondary to a lack of repression by stage-specific KRAB-ZFPs. The KRAB/KAP1-miRNA regulatory cascade is evolutionarily conserved, as it also controls mitophagy during human erythropoiesis. Thus, a multilayered transcription regulatory system is present, in which protein- and RNA-based repressors are superimposed in combinatorial fashion to govern the timely triggering of an important differentiation event

    Can majority support save an endangered language? A case study of language attitudes in Guernsey

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    Many studies of minority language revitalisation focus on the attitudes and perceptions of minorities, but not on those of majority group members. This paper discusses the implications of these issues, and presents research into majority andf minority attitudes towards the endangered indigenous vernacular of Guernsey, Channel Islands. The research used a multi-method approach (questionnaire and interview) to obtain attitudinal data from a representative sample of the population that included politicians and civil servants (209 participants). The findings suggested a shift in language ideology away from the post-second world war ‘culture of modernisation’ and monolingual ideal, towards recognition of the value of a bi/trilingual linguistic heritage. Public opinion in Guernsey now seems to support the maintenance of the indigenous language variety, which has led to a degree of official support. The paper then discusses to what extent this ‘attitude shift’ is reflected in linguistic behaviour and in concrete language planning measures

    Review on the EFDA work programme on nano-structured ODS RAF steels

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    This proceeding is: The 14th International Conference on Fusion Reactor Materials (ICFRM-14) was held at the Sapporo Convention Center in Sapporo, Japan from 7 to 12 September 2009.The 2008─2009 work programme of the European research project on nano-structured oxide dispersion strengthened (ODS) reduced activation ferritic (RAF) steels is being organized along the four following programmatic lines: (1) improve the present generation of nano-structured ODS RAF steels; (2) start the industrial fabrication of the present generation of nano-structured ODS RAF steels; (3) develop an optimised generation of nano-structured and nano-grained ODS RAF steels; (4) investigate the stability of present and optimised generation of nano-structured ODS RAF steels under creep and irradiation. This paper presents the main objectives of current R&D activities being performed within the European research project on nano-structured ODS RAF steels, the main obtained results and the main future activities in the case of the four programmatic lines mentioned just above.This work, supported by the European Communities, was carried out within the framework of the European Fusion Development Agreement.Publicad
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