215 research outputs found

    Uji Efek Ekstrak Daun Papaya (Carica Papaya L.) Terhadap Kadar Gula Darah Tikus Wistar (Rattus Norvegicus) Yang Diinduksi Aloksan

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    : Indonesia is a tropical country with more than 9,600 kinds of medicinal plants; one of them is papaya. Extract of papaya leaf (Carica papaya) is presumed to have hypoglycemia effect because it contains flavonoid, alkaloid, saponin, and tannin. This study aimed to evaluate the effect of papaya leaf extract on elevated blood glucose levels on Wistar rats induced with alloxan. This was an experimental study with 18 male Wistar rats as subjects, divided into 6 groups (3 rats in each group). Group 1, the negative control group, was given aquadest only. Group 2, the positive control group, was treated with alloxan 120 mg/kg body weight (BW) followed by novomix 0.2 iu/200 g BW. Group 3 and 4 were treated with alloxan 120 mg/kg BW followed by papaya leaf extract dosing 250 mg and 500 mg/kg BW respectively. Group 5 and 6 were treated with papaya leaf extract dosing 250 mg and 500 mg/kg BW without alloxan induction. Blood glucose levels were measured on day 1, day 2, and day 3 every six hours at 0, 6, 12, 18, and 24 hours. The results showed that 250 mg/kg BW and 500 mg/kg BW of papaya leaf extract could reduce the elevated blood glucose on Wistar rats for 12 hours after treatment. Conclusion: The extract of papaya leaves could reduce blood sugar levels in hyperglicemic Wistar rats induced by alloxan

    A gas analyzer for the internal polarized target of the HERMES experiment

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    A gas analyzer has been developed for the internal polarized target of the HERMES experiment at DESY in order to determine the relative amount of atomic and molecular hydrogen or deuterium in a gas sample. The precise quantitative knowledge of this ratio is crucial because the nucleons in atoms and molecules contribute differently to the average nuclear polarization of the target gas. A new calibration technique used to derive the relative sensitivity to atoms and molecules is presented. As an example, it is shown how the gas analyzer is used within the HERMES environment to divide the molecules in the gas sample into an unpolarized and a potentially polarized fraction

    The Q2Q^2-dependence of the generalised Gerasimov-Drell-Hearn integral for the deuteron, proton and neutron

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    The Gerasimov-Drell-Hearn (GDH) sum rule connects the anomalous contribution to the magnetic moment of the target nucleus with an energy-weighted integral of the difference of the helicity-dependent photoabsorption cross sections. The data collected by HERMES with a deuterium target are presented together with a re-analysis of previous measurements on the proton. This provides a measurement of the generalised GDH integral covering simultaneously the nucleon-resonance and the deep inelastic scattering regions. The contribution of the nucleon-resonance region is seen to decrease rapidly with increasing Q2Q^2. The DIS contribution is sizeable over the full measured range, even down to the lowest measured Q2Q^2. As expected, at higher Q2Q^2 the data are found to be in agreement with previous measurements of the first moment of g1g_1. From data on the deuteron and proton, the GDH integral for the neutron has been derived and the proton--neutron difference evaluated. This difference is found to satisfy the fundamental Bjorken sum rule at Q2=5Q^2 = 5 GeV2^2.Comment: 12 pages, 10 figure

    Evidence for Quark-Hadron Duality in the Proton Spin Asymmetry A1A_1

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    Spin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A1A_1. Longitudinally polarised positrons were scattered off a longitudinally polarised hydrogen target for values of Q2Q^2 between 1.2 and 12 GeV2^2 and values of W2W^2 between 1 and 4 GeV2^2. The average double-spin asymmetry in the nucleon resonance region is found to agree with that measured in deep-inelastic scattering at the same values of the Bjorken scaling variable xx. This finding implies that the description of A1A_1 in terms of quark degrees of freedom is valid also in the nucleon resonance region for values of Q2Q^2 above 1.6 GeV2^2.Comment: 5 pages, 1 eps figure, table added, new references added, in print in Phys. Rev. Let

    Beam-Induced Nuclear Depolarisation in a Gaseous Polarised Hydrogen Target

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    Spin-polarised atomic hydrogen is used as a gaseous polarised proton target in high energy and nuclear physics experiments operating with internal beams in storage rings. When such beams are intense and bunched, this type of target can be depolarised by a resonant interaction with the transient magnetic field generated by the beam bunches. This effect has been studied with the HERA positron beam in the HERMES experiment at DESY. Resonances have been observed and a simple analytic model has been used to explain their shape and position. Operating conditions for the experiment have been found where there is no significant target depolarisation due to this effect.Comment: REVTEX, 6 pages, 5 figure

    Flavor decomposition of the sea quark helicity distributions in the nucleon from semi-inclusive deep-inelastic scattering

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    Double-spin asymmetries of semi-inclusive cross sections for the production of identified pions and kaons have been measured in deep-inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with re-analyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.Comment: 5 pages, 3 figure
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