487 research outputs found

    Effect of hydrogen on deformation structure and properties of CMSX-2 nickel-base single-crystal superalloy

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    Material used in this study was a heat of the alloy CMSX-2. This nickel-based superalloy was provided in the form of oriented single crystals, solutionized for 3 hrs at 1315 C. It was then usually heat treated as follows: 1050 C/16h/air cool + 850 C/48h/air cool. The resulting microstructure is dominated by cuboidal, ordered gamma precipitates with a volume fraction of about 75% and an average size of 0.5 microns. In brief, the most compelling hydrogen induced-changes in deformation structure are: (1) enhanced dislocation accumulation in the gamma matrix; and (2) more extensive cross-slip of superdislocations in the gamma precipitates. The enhanced dislocation density in gamma acts to decrease the mean free path of a superdislocation, while easier cross slip hinders superdislocation movement by providing pinning points in the form of sessile jobs. Both processes contribute to the increase of flow stress and the notable work hardening that occurs prior to fracture

    A role for core planar polarity proteins in cell contact-mediated orientation of planar cell division across the mammalian embryonic skin

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    Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2017. Supplementary information accompanies this paper at doi:10.1038/s41598-017-01971-2.The question of how cell division orientation is determined is fundamentally important for understanding tissue and organ shape in both healthy or disease conditions. Here we provide evidence for cell contact-dependent orientation of planar cell division in the mammalian embryonic skin. We propose a model where the core planar polarity proteins Celsr1 and Frizzled-6 (Fz6) communicate the long axis orientation of interphase basal cells to neighbouring basal mitoses so that they align their horizontal division plane along the same axis. The underlying mechanism requires a direct, cell surface, planar polarised cue, which we posit depends upon variant post-translational forms of Celsr1 protein coupled to Fz6. Our hypothesis has parallels with contact-mediated division orientation in early C. elegans embryos suggesting functional conservation between the adhesion-GPCRs Celsr1 and Latrophilin-1. We propose that linking planar cell division plane with interphase neighbour long axis geometry reinforces axial bias in skin spreading around the mouse embryo body.Peer reviewe

    Cavity BPM System Tests for the ILC Spectrometer

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    The main physics programme of the International Linear Collider (ILC) requires a measurement of the beam energy at the interaction point with an accuracy of 10−410^{-4} or better. To achieve this goal a magnetic spectrometer using high resolution beam position monitors (BPMs) has been proposed. This paper reports on the cavity BPM system that was deployed to test this proposal. We demonstrate sub-micron resolution and micron level stability over 20 hours for a 1\m long BPM triplet. We find micron-level stability over 1 hour for 3 BPM stations distributed over a 30\m long baseline. The understanding of the behaviour and response of the BPMs gained from this work has allowed full spectrometer tests to be carried out.Comment: Paper submitted to Nuclear Instruments and Methods. 35 pages, 23 figure

    Fostering implementation of health services research findings into practice: a consolidated framework for advancing implementation science

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    Abstract Background Many interventions found to be effective in health services research studies fail to translate into meaningful patient care outcomes across multiple contexts. Health services researchers recognize the need to evaluate not only summative outcomes but also formative outcomes to assess the extent to which implementation is effective in a specific setting, prolongs sustainability, and promotes dissemination into other settings. Many implementation theories have been published to help promote effective implementation. However, they overlap considerably in the constructs included in individual theories, and a comparison of theories reveals that each is missing important constructs included in other theories. In addition, terminology and definitions are not consistent across theories. We describe the Consolidated Framework For Implementation Research (CFIR) that offers an overarching typology to promote implementation theory development and verification about what works where and why across multiple contexts. Methods We used a snowball sampling approach to identify published theories that were evaluated to identify constructs based on strength of conceptual or empirical support for influence on implementation, consistency in definitions, alignment with our own findings, and potential for measurement. We combined constructs across published theories that had different labels but were redundant or overlapping in definition, and we parsed apart constructs that conflated underlying concepts. Results The CFIR is composed of five major domains: intervention characteristics, outer setting, inner setting, characteristics of the individuals involved, and the process of implementation. Eight constructs were identified related to the intervention (e.g., evidence strength and quality), four constructs were identified related to outer setting (e.g., patient needs and resources), 12 constructs were identified related to inner setting (e.g., culture, leadership engagement), five constructs were identified related to individual characteristics, and eight constructs were identified related to process (e.g., plan, evaluate, and reflect). We present explicit definitions for each construct. Conclusion The CFIR provides a pragmatic structure for approaching complex, interacting, multi-level, and transient states of constructs in the real world by embracing, consolidating, and unifying key constructs from published implementation theories. It can be used to guide formative evaluations and build the implementation knowledge base across multiple studies and settings.http://deepblue.lib.umich.edu/bitstream/2027.42/78272/1/1748-5908-4-50.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/2/1748-5908-4-50-S1.PDFhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/3/1748-5908-4-50-S3.PDFhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/4/1748-5908-4-50-S4.PDFhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/5/1748-5908-4-50.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/78272/6/1748-5908-4-50-S2.PDFPeer Reviewe

    The nucleon-nucleon interaction

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    We review the major progress of the past decade concerning our understanding of the nucleon-nucleon interaction. The focus is on the low-energy region (below pion production threshold), but a brief outlook towards higher energies is also given. The items discussed include charge-dependence, the precise value of the πNN\pi NN coupling constant, phase shift analysis and high-precision NN data and potentials. We also address the issue of a proper theory of nuclear forces. Finally, we summarize the essential open questions that future research should be devoted to.Comment: 42 pages, 12 figures, iopart.cls style; Topical Review prepared for J. Phys. G: Nucl. Part. Phy

    Measurement of the branching ratios of the Z0 into heavy quarks

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    We measure the hadronic branching ratios of the Z0 boson into heavy quarks: Rb=Gamma(Z0->bb)/Gamma(Z0->hadrons) and Rc=Gamma(Z0->cc/Gamma(Z0->hadrons) using a multi-tag technique. The measurement was performed using about 400,000 hadronic Z0 events recorded in the SLD experiment at SLAC between 1996 and 1998. The small and stable SLC beam spot and the CCD-based vertex detector were used to reconstruct bottom and charm hadron decay vertices with high efficiency and purity, which enables us to measure most efficiencies from data. We obtain, Rb=0.21604 +- 0.00098(stat.) +- 0.00073(syst.) -+ 0.00012(Rc) and, Rc= 0.1744 +- 0.0031(stat.) +- 0.0020(syst.) -+ 0.0006(Rb)Comment: 37 pages, 8 figures, to be submitted to Phys. Rev. D version 2: changed title to ratios, used common D production fractions for Rb and Rc and corrected Zgamma interference. Identical to PRD submissio

    Oxidative Stress And Frailty: A Systematic Review And Best Evidence Synthesis

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    Objective: Oxidative stress (OS) is associated with accelerated aging. Previous studies have suggested a possible relationship between OS and frailty but this association remains unclear. We conducted a systematic review to investigate potential interactions between OS and frailty. Methods: A systematic literature search of original reports providing data on ‘OS and antioxidant’ parameters and frailty was carried out across major electronic databases from inception until May 2016. Cross-sectional/case control and longitudinal studies reporting data on the association between frailty and anti-oxidants-OS biomarkers were considered for inclusion. Results were summarized with a best-evidence based synthesis. Results: From 1,856 hits, 8 studies (cross-sectional/case control) were included (N = 6,349; mean age of 75 ± 12 years; 56.4% females). Overall, there were 588 (=9.3%) frail, 3,036 pre-frail (=47.8%), 40 (=0.6%) pre-frail/robust, and 2,685 (=42.3%) robust subjects. Six cross-sectional/case control studies demonstrated that frailty was associated with an increase in peripheral OS biomarkers including lipoprotein phospholipase A2 (studies = 1), isoprostanes (studies = 2), Malonaldehyde (studies = 2), 8-hydroxy-20-deoxyguanosine (studies = 2), derivate of reactive oxygen metabolites (studies = 2), oxidized Glutathione/Glutathione (studies = 1), 4-hydroxy-2,3-nonenal (studies = 1), and protein carbonylation levels (study = 1). In addition, preliminary evidence points to lower anti-oxidant parameters (vitamin C, E, α-tocopherol, biological anti-oxidant potential, total thiol levels) in frailty. Conclusion: Frailty and pre-frailty appear to be associated with higher OS and possibly lower anti-oxidant parameters. However, due to the cross sectional design, it is not possible to disentangle the directionality of the relationships observed. Thus, future high quality and in particular longitudinal research is required to confirm/refute these relationships and to further elucidate pathophysiological mechanisms

    Direct Measurements of A_b and A_c using Vertex/Kaon Charge Tags at SLD

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    Exploiting the manipulation of the SLC electron-beam polarization, we present precise direct measurements of the parity violation parameters A_c and A_b in the Z boson - c quark and Z boson - b quark coupling. Quark/antiquark discrimination is accomplished via a unique algorithm that takes advantage of the precise SLD CCD vertex detector, employing the net charge of displaced vertices as well as the charge of kaons that emanate from those vertices. From the 1996-98 sample of 400,000 Z decays, produced with an average beam polarization of 73.4%, we find A_c = 0.673 +/- 0.029 (stat.) +/- 0.023 (syst.) and A_b = 0.919 +/- 0.018 (stat.) +/- 0.017 (syst.).Comment: 11 pages, 2 figures, 2 tables, to be submitted to Physical Review Letters; version 2 reflects changes suggested by the refere

    Search for time-dependent B0s - B0s-bar oscillations using a vertex charge dipole technique

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    We report a search for B0s - B0s-bar oscillations using a sample of 400,000 hadronic Z0 decays collected by the SLD experiment. The analysis takes advantage of the electron beam polarization as well as information from the hemisphere opposite that of the reconstructed B decay to tag the B production flavor. The excellent resolution provided by the pixel CCD vertex detector is exploited to cleanly reconstruct both B and cascade D decay vertices, and tag the B decay flavor from the charge difference between them. We exclude the following values of the B0s - B0s-bar oscillation frequency: Delta m_s < 4.9 ps-1 and 7.9 < Delta m_s < 10.3 ps-1 at the 95% confidence level.Comment: 18 pages, 3 figures, replaced by version accepted for publication in Phys.Rev.D; results differ slightly from first versio
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