Measurement of isomeric yield ratios for the Ho-nat(gamma,xn)Ho-164m,Ho-g;162m,Ho-g reactions in the bremsstrahlung energy region from 45 to 65 MeV

We have measured the isomeric yield ratios for the Ho-164m,Ho-g and the Ho-162m,Ho-g isomeric pairs formed via photonuclear reactions Ho-165(gamma,n)Ho-164m,Ho-g and Ho-165(gamma,3n)Ho-162m,Ho-g in the bremsstrahlung energy region from 45 to 65 MeV in steps of a dagger E = 5 MeV by the activation method. The induced gamma-activities of the irradiated holmium foils were measured by a coaxial high-purity germanium detector coupled to a PC-based multichannel analyzer. In order to improve the accuracy of the experimental results the necessary corrections were made. The experimental results at bremsstrahlung energies of 45, 50, 55, 60, and 65 MeV are 0.408 +/- A 0.027, 0.413 +/- A 0.027, 0.427 +/- A 0.029, 0.452 +/- A 0.032, and 0.448 +/- A 0.031 for the Ho-164m,Ho-g isomeric pair, and 0.587 +/- A 0.041, 0.624 +/- A 0.044, 0.652 +/- A 0.045, 0.637 +/- A 0.045, and 0.668 +/- A 0.046 for the Ho-162m,Ho-g isomeric pair, respectively. The present results are the first measurements at bremsstrahlung energies just above the giant dipole resonance region. The obtained results confirm the dependence of isomeric ratios on the incident photon energy as observed in some earlier experiments.X110sciescopu

Thermal neutron capture and resonance integral cross sections of Sc-45

The thermal neutron cross section (sigma(0)) and resonance integral (I-0) of the Sc-45(n,gamma)Sc-46 reaction have been measured relative to that of the Au-197(n,gamma)Au-198 reaction by means of the activation method. High-purity natural scandium and gold foils without and with a cadmium cover of 0.5 mm thickness were irradiated with moderated pulsed neutrons produced from the Pohang Neutron Facility (PNF). The induced activities in the activated foils were measured with a high purity germanium (HPGe) detector. In order to improve the accuracy of the experimental results the counting losses caused by the thermal (G(th)) and resonance (G(epi)) neutron self-shielding, the gamma-ray attenuation (F-g) and the true gamma-ray coincidence summing effects were made. In addition, the effect of non-ideal epithermal spectrum was also taken into account by determining the neutron spectrum shape factor (alpha). The thermal neutron cross-section and resonance integral of the Sc-45(n,gamma)Sc-46 reaction have been determined relative to the reference values of the Au-197(n,gamma)Au-198 reaction, with sigma(o,Au) = 98.65 +/- 0.09 barn and = 1550 +/- 28 barn. The present thermal neutron cross section has been determined to be sigma(o,Sc) = 27.5 +/- 0.8 barn. According to the definition of cadmium cut-off energy at 0.55 eV, the present resonance integral cross section has been determined to be I-o,I-Sc = 12.4 +/- 0.7 barn. The present results are compared with literature values and discussed. (C) 2015 Elsevier B.V. All rights reserved.1122sciescopu

Measurement of thermal neutron cross section and resonance integral for the Er-170(n,gamma)Er-171 reaction by using a gold monitor

The thermal neutron cross section (sigma(0)) and the resonance integral (I-0) of the reaction Er-170(n,gamma)Er-171 were measured by an activation method using a reaction Au-197(n,gamma)Au-198 as a single comparator. The high-purity natural erbium (Er-nat), and gold (Au-197) foils with and without Cd cover with the thickness of 0.5 mm were irradiated in a neutron field of the Pohang neutron facility. The induced activities in the activated foils were measured with a well calibrated coaxial HPGe detector. The thermal neutron cross section for the Er-170(n,gamma)Er-171 reaction has been determined to be sigma(0) = 7.80 +/- 0.35 barn, relative to the reference value of 98.65 +/- 0.09 barn for the Au-197(n,gamma)Au-198 reaction. By assuming the cadmium cutoff energy of 0.55 eV, the resonance integral for the Er-170(n,gamma)Er-171 reaction is I-0 = 40.4 +/- 2.8 barn, which is determined relative to the reference value of 1550 +/- 28 barn for the Au-197(n,gamma)Au-198 reaction. In order to improve the accuracy of the experimental results the epithermal neutron spectrum shape factor (alpha) was determined, and the necessary corrections for the counting loss caused by gamma-ray attenuation (F-g), the thermal neutron shelf-shielding (G(th)), the resonance neutron self-shielding (G(epi)) effects, the gamma-ray coincidence summing effect, as well as neutron flux fluctuation. The present results are compared with the reference data and discussed. (C) 2013 Elsevier B.V. All rights reserved.X110sciescopu

Thermal neutron capture cross section and resonance integral of the La-139(n,gamma)La-140 reaction

The thermal neutron capture cross section (sigma(o)) and resonance integral cross section (I-0) of the La-139(n,gamma)La-140 reaction have been measured relative to that of the Au-197(n,gamma)Au-198 reaction by means of the activation method. High-purity natural lanthanum and gold foils were exposed to pulsed neutrons at the Pohang neutron facility. One set of foils was irradiated directly and a second set of foils was shielded with a cadmium cover of 0.5 mm thickness. The induced activities in the activated foils were measured by a gamma-ray spectrometer based on a calibrated high purity germanium (HPGe) detector. In order to improve the accuracy of the experimental results the epithermal neutron spectrum shape factor (alpha) was determined, and the corrections for the thermal neutron self-shielding (G(th)), the resonance neutron self-shielding (G(epi)), the gamma-ray attenuation (F-g) and the gamma-ray coincidence summing effects were made. The thermal neutron cross-section for the La-139(n,gamma)La-140 reaction has been determined to be 9.16 +/- 0.36 barn, relative to the reference value of 98.65 +/- 0.09 barn for the Au-197(n,gamma)Au-198 reaction. By assuming the cadmium cut-off energy of 0.55 eV, the resonance integral cross section for the La-139(n,gamma)La-140 reaction is 11.64 +/- 0.69 barn, which is determined relative to the reference value of 1550 +/- 28 barn for the Au-197(n,gamma)Au-198 reaction. The measured results are compared with literature values and discussed. (C) 2014 Elsevier B.V. All rights reserved.X1113sciescopu

Isomeric yield ratios for the Ag-nat(gamma,xn)Ag-106m,Ag-g;104m,Ag-g photonuclear reactions induced by 40-, 45-, 50-, 55-, and 60-MeV bremsstrahlung

We have determined the isomeric yield ratios for the isomeric pairs Ag-106m,Ag-g and Ag-104m,Ag-g produced on natural silver target nuclei in the bremstrahlung energy region from 40- to 60-MeV. The measurements were carried out by the activation method in combination with direct gamma-spectrometry. The necessary corrections were made to improve the accuracy of the experimental results. The present yield ratios measured at 40, 45, 50, 55, and 60 MeV for the Ag-106m,Ag-g isomeric pair are 0.019 +/- 0.002, 0.022 +/- 0.002, 0.023 +/- 0.002, 0.025 +/- 0.002, and 0.025 +/- 0.002, and those for the Ag-104m,Ag-g isomeric pair are 1.26 +/- 0.12, 1.34 +/- 0.12, 1.36 +/- 0.12, 1.43 +/- 0.12, and 1.49 +/- 0.12, respectively. The obtained results are compared with those existing in literature and discussed. (C) 2014 Elsevier B.V. All rights reserved.X1123sciescopu

Role of nicotinic acid in raising high-density lipoprotein cholesterol (HDL-C) to reduce cardiovascular risk: An Asian/Pacific consensus

Cardiovascular disease is a leading cause of morbidity and mortality in Asia, and the burden of disease is expected to rise further in the 21st century. As in Western populations, dyslipidaemia is an important cardiovascular risk factor in Asian people. International guidelines focus on reduction of low-density lipoprotein cholesterol (LDL-C) for prevention and treatment of coronary heart disease (CHD). However, increasing body mass index and prevalence of type 2 diabetes and metabolic syndrome in Asia have highlighted the importance of low levels of high-density lipoprotein cholesterol (HDL-C) as a coronary risk factor. Therapeutic lifestyle changes and pharmacological intervention aimed at raising HDL-C, should benefit such patients. Weight loss and physical exercise are important interventions for raising HDL-C. However, to achieve target HDL-C levels pharmacological intervention is usually necessary. Current treatment options include statins, fibrates and nicotinic acid, either as monotherapy or in combination. Statins are generally regarded as the foundation of lipid-modifying therapy. Mainly via reduction of LDL-C. Both fibrates and nicotinic acid are effective in raising HDL-C levels, and reducing triglyceride-rich lipoproteins. The efficacy and safety profile of nicotinic acid demonstrated in Western populations indicates the clinical benefits of this therapy either alone or in combination with a statin. Based on the available evidence, the Pan-Asian Consensus Panel recommends that HDL-C levels should be raised to at least 1.0 mmol/L (40 mg/dL) in Asian patients with CHD or with a high level of risk for premature vascular disease, including patients at high risk with type 2 diabetes or the metabolic syndrome.link_to_subscribed_fulltex