3,436 research outputs found

    Measurement of the inclusive jet cross section with the ATLAS detector

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    The data collected in ATLAS at ‚ąös = 7TeV in 2010, are being used to perform the measurement of the inclusive jet cross section. The inclusive jet cross section is measured in different rapidity intervals up to very forward regions (|y| < 4.4), with transverse momentum in the interval 0.02‚Äď1.5TeV for central rapidities. The systematics of the measurement has been widely investigated, and the impact of the uncertainty on the energy calibration of jets, which is the cause of the dominant uncertainty in the measurement, is discussed

    Transverse voltage in high-Tc superconductors in zero magnetic fields

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    Longitudinal and transverse voltages have been measured in zero external magnetic fields. In close vicinity of the superconducting transition nonzero transverse voltage has been observed while far away from Tc, both above and below no such voltage has been detected. The value of the transverse resistivity depends on the value of the transport current. Several models have been discussed taking into account also the penetration of self field due to the applied transport current. It seems that observed results can be explained using the Kosterlitz-Thouless model as a result of an unpairing of vortex-antivortex pairs created below Tkt due to fluctuations. At Tkt free vortices and antivortices are created and can contribute to a dissipation of energy. Their movement should also be responsible for the observed nonzero transverse voltage.Comment: 3 pages in Latex, 3 figs.ep

    Scaling of resistivities and guided vortex motion in MgB2 thin films

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    Longitudinal and transverse voltages have been measured on thin films of MgB2 with different superconducting transition widths. The study has been performed in zero and non-zero external magnetic fields. The non-zero transverse voltage has been observed in close vicinity of the critical temperature in zero external magnetic field, while further away from Tc this voltage becomes zero. In magnetic field it becomes a transverse voltage which is an even function with respect to the direction of the field. The usual Hall voltage starts to appear with increasing magnetic field and in large fields the even voltage disappears and only the Hall voltage is measurable (i.e. the transverse even voltage is suppressed with increasing magnetic field and increasing transport current). New scaling between transverse and longitudinal resistivities has been observed. This correlation is valid not only in the zero magnetic field but also in nonzero magnetic field where transverse even voltage is detected. Several models trying to explain observed results are discussed. The most promising one seems to be guided motion of the vortices, though further theoretical work will be required to confirm this

    Regenerating Rat Liver: Correlations Between Estrogen Receptor Localization and Deoxyribonucleic Acid Synthesis

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    Estrogen receptor activity was quantitated in the cytosol and nucleus of normal rat liver and in regenerating rat liver at several time intervals after 75% hepatectomy. Cytosolic estradiol binding in regenerating liver decreases at 12, 24, and 48 h after hepatectomy and at 48 h is 30% of that in normal rat liver. Nuclear estrogen binding 48 h after surgery is elevated fivefold over normal values. No alterations in affinity of the receptor for estrogen have been observed. Specificity studies indicate that the estrogen receptors from both normal and regenerating liver were similar and are highly specific for estrogens. These changes in cellular distribution of receptors parallel increases in nuclear deoxyribonucleic acid synthesis and mitotic indices in the liver. © 1984, American Gastroenterological Association. All rights reserved

    Estrogen Binding Protein Activity in Morris Hepatoma 7777 Compared With Normal Rat Liver

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    Estrogen binding protein activities were determined in the cytosol from adult male Buffalo rat liver and Morris hepatoma 7777. Estrogen receptors were prepared using the protamine sulfate precipitation technique of Chamness. The ability of various unlabeled steroids competing with [3H]estradiol was examined to establish the binding specificity. Estradiol binding in Morris hepatoma 7777 cytosol was greatly decreased compared with that present in hepatic cytosol prepared from normal rat liver. The receptor concentration expressed as femtomoles per milligram of cytoplasmic protein was 31.1 ¬Ī 2.9 SD for normal rat liver and 0.41 ¬Ī 0.88 SD for the hepatoma. Gel filtration chromatography revealed the presence of an estrogen binder in hepatoma cytosol which was not present in either normal liver or in the protamine sulfate precipitates of hepatoma cytosol. The molecular weight, binding specificity, and precipitation of this protein by specific antiserum suggests that it is őĪ-fetoprotein. ¬© 1984, American Gastroenterological Association. All rights reserved

    The effect of estrogen and tamoxifen on hepatocyte proliferation in Vivo and in Vitro

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    We have previously shown that changes in estrogen‚Äźhepatocyte interaction occur during liver regeneration. Following 70% hepatectomy, estrogen levels in the blood were elevated, the number of estrogen receptors in the liver was increased and there was an active translocation of estrogen receptors from the cytosol to the nucleus. The injection of tamoxifen, an estrogen antagonist, inhibits hepatocyte proliferation following partial hepatectomy. The administration of 1 őľg tamoxifen per gm body weight at zero time or 6 hr after the operation resulted in a significant inhibition both of DNA synthesis and of the number of cells in mitosis. Injections of tamoxifen 12 hr or later after the operation had no effect. Concomitant injections of equimolar amounts of estrogen abolished the inhibition by tamoxifen. The effects of estrogen and tamoxifen were also tested on hepatocytes in primary culture. Estrogens in the presence of 5% normal rat serum stimulated hepatocyte DNA synthesis as determined by [3H]thymidine incorporation and the labeling index, whereas epidermal growth factor‚Äźinduced DNA synthesis in the absence of normal rat serum was strongly inhibited. Tamoxifen, in contrast, inhibited DNA synthesis of hepatocytes in the presence of 5% normal rat serum and reversed the stimulatory effect of estrogen in the same system. Attempts to elucidate the mechanism of tamoxifen inhibition in vitro indicated that one effect of tamoxifen is to prevent the amiloride‚Äźsensitive Na+ influx necessary to initiate hepatocyte proliferation. Copyright ¬© 1989 American Association for the Study of Liver Disease

    Estradiol and testosterone levels in patients undergoing partial hepatectomy - A possible signal for hepatic regeneration?

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    In five adult male patients undergoing a 40-60% partial hepatectomy, serum sex hormone levels before and after hepatic resection were determined. Blood was drawn immediately prior to each surgical procedure and at specified time points postoperatively. Compared to hormone levels found prior to surgery, following major hepatic resection, estradiol levels increase at 24 and 48 hr, while testosterone levels decline, being significantly reduced at 96 and 144 hr. These data demonstrate that adult males who undergo a 40-60% partial hepatectomy experience alterations in their sex hormone levels similar to those observed in male rats following a 70% hepatectomy. These changes in sex hormone levels have been associated in animals with an alteration of the sex hormone receptor status of the liver that is thought to participate in the initiation of the regenerative response. These studies suggest, but do not prove, that in man, as in the case of the rat, sex hormones may participate in the initiation of or at least modulate in part the regenerative response that occurs following a major hepatic resection. © 1989 Plenum Publishing Corporation

    Different response to epidermal growth factor of hepatocytes in cultures isolated from male or female rat liver. Inhibitor effect of estrogen on binding and mitogenic effect of epidermal growth factor

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    Deoxyribonucleic acid (DNA) synthesis in hepatocytes isolated from the livers of male and female rats has been compared in monolayer culture. Plating efficiency, DNA and protein content, viability, and morphologic appearance were the same in cultures prepared with hepatocytes isolated from male or female rats. Epidermal growth factor (EGF)-induced DNA synthesis was significantly higher in hepatocytes from male rats than in hepatocytes from female rats. This was the case whether hepatocytes were isolated from normal or partially hepatectomized male or female rats. Hepatocytes isolated from regenerating liver synthesize more DNA than those isolated from normal liver in response to EGF. This increased response to EGF in hepatocytes derived from regenerating liver was relatively the same for male- and female-derived hepatocytes, but the magnitude of the response was considerably higher in male-derived hepatocytes. In contrast, in vivo DNA synthesis in the liver remnant after partial hepatectomy was similar in male and female rats if measured 24 h after the operation. A comparison of EGF binding to male- and female-derived hepatocytes maintained in primary culture indicated a lower number of high-affinity receptors for EGF in the female hepatocytes. The addition of estrogen to primary cultures of hepatocytes isolated from male rats inhibited EGF binding as well as EGF-induced DNA synthesis. Our studies show significant differences in DNA synthesis in response to EGF when male and female hepatocytes are compared in primary culture. The regenerative response after partial hepatectomy, on the other hand, was the same in male and female rats. Thus, our studies indicate that the sex of the donor rat is important when hepatocytes in culture are used for a variety of studies, such as hepatocyte metabolism, induction and control of DNA synthesis, and hepatocarcinogenesis. In addition, our results indicate that caution is advised when inferences are made from in vitro findings for in vivo conditions. © 1987
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