1,961 research outputs found

    Use of borohydride to determine the difference in the developable density for a chemically sensitized and non-sensitized emulsion.

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    An emulsion prepared so as to minimize the effect of any chemical action on the grains was in its primitive state, i.e., that no chemical sensitizing had occurred during the formation of the emulsion grains in inert gelatin. Another emulsion was made so as to maximize the effect of any chemical action on the grains by chemical sensitizing methods. This emulsion was also prepared in inert gelatin. Sodium Borohydride was added at various levels of concentration to chemically fog both emulsions. The developable density was measured. Also, an attempt was made to measure the amount of reduction sensitization occurring if any. The loss of sodium borohydride in a 1.0 N sodium hydroxide solution was minimum for the time used. An appreciable difference in the photographic effect produced by the use of sodium borohydride was measured and observed. Density is proportional to concentration of sodium borohydride added for the primitive emulsion. Some reduction sensitization was measurable on the primitive emulsion

    Open and reproducible science practices in psychoneuroendocrinology: Opportunities to foster scientific progress

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    This perspective article was written by invitation of the editors in chief as a summary and extension of the symposium entitled Psychoneuroendocrine Research in the Era of the Replication Crisis which was held at the virtual meeting of the International Society of Psychoneuroendocrinology 2021. It highlights the opportunities presented by the application of open and reproducible scientific practices in psychoneuroendocrinology (PNE), an interdisciplinary field at the intersection of psychology, endocrinology, immunology, neurology, and psychiatry. It conveys an introduction to the topics preregistration, registered reports, quantifying the impact of equally-well justifiable analysis decisions, and open data and scripts, while emphasizing ‘selfish’ reasons to adopt such practices as individual researcher. Complementary to the call for adoption of open science practices, we highlight the need for methodological best practice guidelines in the field of PNE, which could further contribute to enhancing replicability of results. We propose concrete steps for future actions and provide links to additional resources for those interested in adopting open and reproducible science practices in future studies

    The exponential map for the unitary group SU(2,2)

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    In this article we extend our previous results for the orthogonal group, SO(2,4)SO(2,4), to its homomorphic group SU(2,2)SU(2,2). Here we present a closed, finite formula for the exponential of a 4×44\times 4 traceless matrix, which can be viewed as the generator (Lie algebra elements) of the SL(4,C)SL(4,C) group. We apply this result to the SU(2,2)SU(2,2) group, which Lie algebra can be represented by the Dirac matrices, and discuss how the exponential map for SU(2,2)SU(2,2) can be written by means of the Dirac matrices.Comment: 10 page

    The Geometry and Moduli of K3 Surfaces

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    These notes will give an introduction to the theory of K3 surfaces. We begin with some general results on K3 surfaces, including the construction of their moduli space and some of its properties. We then move on to focus on the theory of polarized K3 surfaces, studying their moduli, degenerations and the compactification problem. This theory is then further enhanced to a discussion of lattice polarized K3 surfaces, which provide a rich source of explicit examples, including a large class of lattice polarizations coming from elliptic fibrations. Finally, we conclude by discussing the ample and Kahler cones of K3 surfaces, and give some of their applications.Comment: 34 pages, 2 figures. (R. Laza, M. Schutt and N. Yui, eds.

    A validation of the Oswestry Spinal Risk Index

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    Purpose The purpose of this study was to validate the Oswestry Spinal Risk Index (OSRI) in an external population. The OSRI predicts survival in patients with metastatic spinal cord compression (MSCC). Methods We analysed the data of 100 patients undergoing surgical intervention for MSCC at a tertiary spinal unit and recorded the primary tumour pathology and Karnofsky performance status to calculate the OSRI. Logistic regression models and survival plots were applied to the data in accordance with the original paper. Results Lower OSRI scores predicted longer survival. The OSRI score predicted survival accurately in 74% of cases (p = 0.004). Conclusions Our study has found that the OSRI is a significant predictor of survival at levels similar to those of the original authors and is a useful and simple tool in aiding complex decision making in patients presenting with MSC

    Methyl 4-phenyl-1,2,3,3a,4,4a,5,12c-octa­hydronaphtho[1′,2′:3,2]furo[5,4-b]pyrrolizine-4a-carboxyl­ate

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    In the title compound, C26H25NO3, both pyrrolidine rings adopt envelope conformations, whereas the dihydro­pyran ring adopts a half-chair conformation. The phenyl ring is oriented at an angle of 27.9 (1)° with respect to the naphthalene ring system. An intra­molecular C—H⋯O hydrogen bond is observed. The crystal packing is stabilized by weak inter­molecular C—H⋯π inter­actions

    A simply connected surface of general type with p_g=0 and K^2=2

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    In this paper we construct a simply connected, minimal, complex surface of general type with p_g=0 and K^2=2 using a rational blow-down surgery and Q-Gorenstein smoothing theory.Comment: 19 pages, 6 figures. To appear in Inventiones Mathematica

    Gene expression in American lobster (Homarus americanus) with epizootic shell disease

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    Author Posting. © National Shellfisheries Association, 2012. This article is posted here by permission of National Shellfisheries Association for personal use, not for redistribution. The definitive version was published in Journal of Shellfish Research 31 (2012): 505-513, doi:10.2983/035.031.0210.Epizootic shell disease (ESD) has been reported widely in American lobster (Homarus americanus, Milne Edwards) in southern New England. The appearance of irregular, deep lesions—characteristic of ESD—has been associated previously with elevated levels of ecdysteroids and premature molting, but the underlying molecular and physiological changes associated with ESD remain poorly understood. Previously, we identified several genes, including arginine kinase and hemocyanin, that were expressed differentially in lobsters exhibiting signs of ESD (diseased) versus those lobsters exhibiting no signs of ESD (assumed healthy), and quantified their expression. In this study, we extend these findings and measure expression of a suite of 12 genes in tissues from 36 female lobsters of varying disease condition. In addition, molt stage is evaluated as a possible confounding factor in the expression of the selected genes. The expression of several genes changed significantly with disease stage. Arginine kinase expression decreased significantly in thoracic muscle of lobsters with signs of ESD. Ecdysteroid receptor expression was elevated significantly in both muscle and hepatopancreas of lobsters with signs of ESD. CYP45, a cytochrome P450 form that was shown previously to covary with ecdysteroid levels and to be inducible by some xenobiotics, showed significantly increased expression in hepatopancreas of lobsters with signs of ESD. Together, these results demonstrate that the expression of several genes is altered in lobsters showing signs of ESD, even when accounting for variation in molt stage. Given the observed changes in ecdysteroid receptor, arginine kinase, and CYP45 expression, further investigations of the association, if any, between molting, muscular function and xenobiotic metabolism and ESD are warranted.This work was supported by the National Marine Fisheries Service as the New England Lobster Research Initiative: Lobster Shell Disease under NOAA grant NA06NMF4720100 to the University of Rhode Island Fisheries Center

    Inhibition of gastric H,K-ATPase activity and gastric epithelial cell IL-8 secretion by the pyrrolizine derivative ML 3000

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    BACKGROUND: ML 3000 ([2,2-dimethyl-6-(4-chlorophenyl)-7-phenyl-2,3-dihydro-1H-pyrrolizine-5-yl]-acetic acid) is an inhibitor of both cyclooxygenase and 5-lipoxygenase in vitro, and shows promise as a novel non-steroidal anti-inflammatory drug (NSAID). Unlike conventional NSAIDs which are associated with gastric ulcerogenic effects, ML 3000 causes little or no damage to the gastric mucosa, even though it significantly depresses gastric prostaglandin synthesis. METHODS: As part of an effort to clarify mechanisms underlying the gastric sparing properties of ML 3000, we studied the effects of ML 3000 on H,K-ATPase activity in vitro, on acid accumulation in isolated gastric parietal cells, and on IL-8 secretion by gastric epithelial cells in culture. RESULTS: SCH28080-sensitive H,K-ATPase activity in highly-purified pig gastric microsomes was dose-dependently inhibited by ML 3000 (IC(50) = 16.4 μM). Inhibition was reversible, and insensitive to ML 3000 acidification in the pH range 2.0–8.0. In rabbit gastric parietal cells, ML 3000 dose-dependently inhibited histamine-stimulated acid accumulation (IC(50) = 40 μM) and forskolin-stimulated acid accumulation (IC(50) = 45 μM). Lastly, in human gastric adenocarcinoma (AGS) cells, ML 3000 dose-dependently inhibited both baseline and IL-1β-stimulated (20 ng/ml) IL-8 secretion with IC(50)s of 0.46 μM and 1.1 μM respectively. CONCLUSION: The data indicate that ML 3000 affects acid-secretory mechanisms downstream of cAMP mobilization induced by histamine H(2) receptor activation, that it directly inhibits H,K-ATPase specific activity, and that baseline gastric epithelial cell IL-8 secretory inhibition may be mediated by ML 3000 inhibition of 5-lipoxygenase activity. We conclude that these gastric function inhibitory data may underlie the gastric sparing properties of ML 3000
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