5,669 research outputs found

    Is the Coulomb sum rule violated in nuclei?

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    Guided by the experimental confirmation of the validity of the Effective Momentum Approximation (EMA) in quasi-elastic scattering off nuclei, we have re-examined the extraction of the longitudinal and transverse response functions in medium-weight and heavy nuclei. In the EMA we have performed a Rosenbluth separation of the available world data on 40^{40}Ca, 48^{48}Ca, 56^{56}Fe, 197^{197}Au, 208^{208}Pb and 238^{238}U. We find that the longitudinal response function for these nuclei is "quenched" and that the Coulomb sum is not saturated, at odds with claims in the literature.Comment: 10 pages, 6 figure

    Purification of Curcumin from Ternary Extract-Similar Mixtures of Curcuminoids in a Single Crystallization Step

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    Crystallization-based separation of curcumin from ternary mixtures of curcuminoids having compositions comparable to commercial extracts was studied experimentally. Based on solubility and supersolubility data of both, pure curcumin and curcumin in presence of the two major impurities demethoxycurcumin (DMC) and bis(demethoxy)curcumin (BDMC), seeded cooling crystallization procedures were derived using acetone, acetonitrile and 50/50 (wt/wt) mixtures of acetone/2-propanol and acetone/acetonitrile as solvents. Starting from initial curcumin contents of 67–75% in the curcuminoid mixtures single step crystallization processes provided crystalline curcumin free of BDMC at residual DMC contents of 0.6–9.9%. Curcumin at highest purity of 99.4% was obtained from a 50/50 (wt/wt) acetone/2-propanol solution in a single crystallization step. It is demonstrated that the total product yield can be significantly enhanced via addition of water, 2-propanol and acetonitrile as anti-solvents at the end of a cooling crystallization process

    Aldehyde Fixation Causes Membrane Vesiculation During Platelet Exocytosis: A Freeze-Substitution Study

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    Despite a plethora of reports on the ultrastructure of secretory granule release by exocytosis, the release of coagulant activity from stimulated platelets is still being attributed to membrane vesiculation. Membrane vesiculation and the formation of myelin figures have been shown to be artifacts of glutaraldehyde GA fixation. Cells fixed by direct osmium or rapid freezing are free of such structures. Yet there is still doubt that rapid freezing interferes with vesiculation process. This study has addressed this issue by examining: (1) whether freezing and freeze-substitution affects membrane vesiculation, (2) whether paraformaldehyde-fixation also induces the phenomenon, and (3) whether the aldehyde concentration is of influence. Aldehyde fixation was carried out prior to impact freezing and freeze-substitution. In thrombin-stimulated platelets, membrane vesiculation and myelin figures were found. Glutaraldehyde induced multivesicular structures, paraformaldehyde or low aldehyde concentrations only blebs on the platelet surface. The membrane vesicles were in continuity with the cytoplasmic matrix. Unstimulated platelets did not show vesiculation or myelin figures. Control samples, without aldehyde fixation, showed instead of membrane vesiculation, granule fusion with the plasmalemma, or, instead of myelin figures, compound granules. This confirms that membrane vesiculation and the formation of myelin figures are artifacts induced by the failure of aldehydes to arrest lipid mobility within membranes undergoing rapid changes in structure. Although the presence of membrane vesiculation and myelin figures in platelets indicates that exocytotic processes were occurring at the moment of aldehyde fixation, the finding of membrane vesiculation in aldehyde-fixed platelets does not indicate a separate type of exocytosis

    Dispositional empathy, dyadic perspective-taking, and interpersonal perceptions among married persons in relation to marital adjustment

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    Several studies have shown that various aspects of empathy are important in relationship satisfaction. In addition, the similarity, assumed similarity, and accuracy of interpersonal perceptions among married couples have also been shown to be positively related to marital adjustment. The present study examined these variables in a sample of 42 married couples. It was found that Perspective-Taking and Empathic Concern, as well as Dyadic Perspective-Taking were positively associated with marital adjustment. In addition, it was observed that accuracy of interpersonal perceptions was positively related to marital satisfaction and satisfaction regarding conflict resolutions. This significant correlation did not remain, however, when the effects of similarity and assumed similarity were taken into account. Finally, it was proposed that Perspective-Taking ability would be positively related to accuracy of interpersonal perceptions. This hypothesis was largely unsupported

    Investigation of LANDSAT follow-on thematic mapper spatial, radiometric and spectral resolution

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    The author has identified the following significant results. Fine resolution M7 multispectral scanner data collected during the Corn Blight Watch Experiment in 1971 served as the basis for this study. Different locations and times of year were studied. Definite improvement using 30-40 meter spatial resolution over present LANDSAT 1 resolution and over 50-60 meter resolution was observed, using crop area mensuration as the measure. Simulation studies carried out to extrapolate the empirical results to a range of field size distributions confirmed this effect, showing the improvement to be most pronounced for field sizes of 1-4 hectares. Radiometric sensitivity study showed significant degradation of crop classification accuracy immediately upon relaxation from the nominally specified values of 0.5% noise equivalent reflectance. This was especially the case for data which were spectrally similar such as that collected early in the growing season and also when attempting to accomplish crop stress detection

    Competitive Diffusion and Adsorption of Gas Mixtures in Vycor Glass Membranes

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    see attached file "Abstract_ICCMR-7_Schluender_Cetraro.pdf

    A daily diary study of stressful and positive events, alcohol use, and addiction severity among heavy drinking sexual minority men

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    © 2018 Elsevier B.V. Background: The purpose of this study is to examine the conditions under which daily stressful and positive events are associated with alcohol use among heavy drinking sexual minority men (SMM). Specifically, we examined the moderating effects of two indicators of alcohol addiction severity (i.e., alcohol dependence severity and negative drinking consequences) on the associations between daily stressful events and alcohol use and between daily positive events and alcohol use among heavy drinking SMM. Procedures: Secondary data analyses were performed using data from a randomized controlled trial of heavy drinking and treatment seeking SMM who were assigned male at birth (N = 200). Participants responded to a daily survey delivered via interactive voice recording (IVR). The first seven days of the IVR were analyzed for this study. Results: While accounting for treatment condition, weekday/weekend, and baseline drinking, stressful and positive events were both associated with increased daily drinking; however, indicators of alcohol addiction severity moderated these associations. For heavy drinkers with high alcohol addiction severity, daily stressful events were not associated with alcohol use, and daily positive events were associated with increased alcohol use. In contrast, for heavy drinkers with low alcohol addiction severity, daily stressful events were associated with less drinking, and daily positive events were not associated with alcohol use. Conclusions: The findings of this study indicate that alcohol addiction severity plays a key role in explaining when daily stressful or positive events are associated with daily alcohol use among heavy drinking SMM

    The use of complementary and alternative medicine among california adults with and without cancer.

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    This article examines the extent and correlates of complementary and alternative medicine (CAM) use among a population-based sample of California adults that is highly diverse in terms of sociodemographic characteristics and health status. As a follow-up to a state-wide health survey of 55,428 people, 9187 respondents were interviewed by phone regarding their use of 11 different types of CAM providers, special diets, dietary supplements, mind-body interventions, self-prayer and support groups. The sample included all participants in the initial survey who reported a diagnosis of cancer, all the non-white respondents, as well as a random sample of all the white respondents. The relation of CAM use to the respondents' demographic characteristics and health status is assessed. CAM use among Californians is generally high, and the demographic factors associated with high rates of CAM use are the same in California as have been found in other studies. Those reporting a diagnosis of cancer and those who report other chronic health problems indicate a similar level of visits to CAM providers. However, those with cancer are less likely to report using special diets, and more likely to report using support groups and prayer. Health status, gender, ethnicity and education have an independent impact upon CAM use among those who are healthy as well as those who report suffering from chronic health problems, although the precise relation varies by the type of CAM used
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