346 research outputs found

    Search for solar axions produced by Compton process and bremsstrahlung using the resonant absorption and axioelectric effect

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    The search for resonant absorption of Compton and bremsstrahlung solar axions by 169^{169}Tm nuclei have been performed. Such an absorption should lead to the excitation of low-lying nuclear energy level: A+169A+^{169}Tm β†’169\rightarrow ^{169}Tmβˆ—^* β†’169\rightarrow ^{169}Tm +Ξ³+ \gamma (8.41 keV). Additionally the axio-electric effect in silicon atoms is sought. The axions are detected using a Si(Li) detectors placed in a low-background setup. As a result, a new model independent restrictions on the axion-electron and the axion-nucleon coupling: gAeΓ—βˆ£gAN0+gAN3βˆ£β‰€2.1Γ—10βˆ’14g_{Ae}\times|g^0_{AN}+ g^3_{AN}|\leq 2.1\times10^{-14} and the axion-electron coupling constant: ∣gAeβˆ£β‰€2.2Γ—10βˆ’10|g_{Ae}| \leq 2.2\times 10^{-10} has been obtained. The limits leads to the bounds mA≀m_{A}\leq 7.9 eV and mA≀m_{A}\leq 1.3 keV for the mass of the axion in the DFSZ and KSVZ models, respectively (90%90\% C.L.).Comment: 6 pages, 3 figures, contributed to the 9th Patras Workshop on Axions, WIMPs and WISPs, Mainz, June 24-28, 201

    Malignant hyperthermia: current approaches to prevention and treatment

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    One of the most serious complications of modern anesthesia is malignant hyperthermia, which is a pharmacogenetic disease phenotype manifested by skeletal muscle hypermetabolism and rhabdomyolysis during or after general anesthesia with the use of inhaled anesthetics and succinylcholine. In Russia, the problem of malignant hyperthermia remains unresolved. This is mainly due to the fact that the only specific drug dantrolene created for the effective treatment of malignant hyperthermia is still not legalized and thus formally prohibited to import, disseminate and apply on the domestic pharmaceutical market. This article deals with the regulatory framework of specific treatment of malignant hyperthermia in Russia, allowing the possibility to legally import to the territory of the Russian Federation dantrolene as an unregistered drug, if it is a question of rendering medical assistance on vital indications to a particular patient, or its unauthorized use for vital indications in a situation of extreme necessity. The article presents the recommendations of domestic experts on the treatment of malignant hyperthermia. In this case, as a possible alternative to dantrolene, magnesium preparations are considered, whose role in the treatment of the crisis of malignant hyperthermia continues to be specified. Thus, given the increasing use of inhalation anesthesia by Russian anesthetists, to ensure the safety of patients with regard to the development of malignant hyperthermia, it is possible only in the case of official registration in the domestic dantrolene market. Also, in the territory of Russia, a network of relevant consultative and diagnostic centers should be established. These measures will undoubtedly increase the effectiveness of treatment and prevention of severe consequences of this disease in our country

    New limit on the mass of 9.4-keV solar axions emitted in an M1 transition in 83^{83}Kr nuclei

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    A search for resonant absorption of the solar axion by 83Kr^{83}\rm{Kr} nuclei was performed using the proportional counter installed inside the low-background setup at the Baksan Neutrino Observatory. The obtained model independent upper limit on the combination of isoscalar and isovector axion-nucleon couplings ∣g3βˆ’g0βˆ£β‰€1.69Γ—10βˆ’6|g_3-g_0|\leq 1.69\times 10^{-6} allowed us to set the new upper limit on the hadronic axion mass of mA≀130m_{A}\leq 130 eV (95\% C.L.) with the generally accepted values SS=0.5 and zz=0.56.Comment: 5 pages, 2 figures, Proceedings of the 10th Patras Workshop on Axions, WIMPs and WISP 29 June - 4 July 2014, CERN, Geneva, Switzerlan

    Constraints on the axion-electron coupling for solar axions produced by Compton process and bremsstrahlung

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    The search for solar axions produced by Compton (Ξ³+eβˆ’β†’eβˆ’+A\gamma+e^-\rightarrow e^-+A) and bremsstrahlung-like (eβˆ’+Zβ†’Z+eβˆ’+Ae^-+Z \rightarrow Z+e^-+A) processes has been performed. The axion flux in the both cases depends on the axion-electron coupling constant. The resonant excitation of low-lying nuclear level of 169Tm^{169}\rm{Tm} was looked for: A+169A+^{169}Tm β†’169\rightarrow ^{169}Tmβˆ—^* β†’169\rightarrow ^{169}Tm +Ξ³+ \gamma (8.41 keV). The Si(Li) detector and 169^{169}Tm target installed inside the low-background setup were used to detect 8.41 keV Ξ³\gamma-rays. As a result, a new model independent restriction on the axion-electron and the axion-nucleon couplings was obtained: gAeΓ—βˆ£gAN0+gAN3βˆ£β‰€2.1Γ—10βˆ’14g_{Ae}\times|g^0_{AN}+ g^3_{AN}|\leq 2.1\times10^{-14}. In model of hadronic axion this restriction corresponds to the upper limit on the axion-electron coupling and on the axion mass gAeΓ—mA≀3.1Γ—10βˆ’7g_{Ae}\times m_A\leq3.1\times10^{-7} eV (90% c.l.). The limits on axion mass are mA≀m_A\leq 105 eV and mA≀m_A\leq 1.3 keV for DFSZ- and KSVZ-axion models, correspondingly (90% c.l.).Comment: 7 pages, 4 figure

    Searches for axioelectric effect of solar axions with BGO-scintillator and BGO-bolometer detectors

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    A search for axioelectric absorption of 5.5 MeV solar axions produced in the p+dβ†’3He+Ξ³Β (5.5Β MeV)p + d \rightarrow {^3\rm{He}}+\gamma~(5.5~ \rm{MeV}) reaction has been performed with a BGO detectors. A model-independent limit on the product of axion-nucleon gAN3g_{AN}^3 and axion-electron gAeg_{Ae} coupling constants has been obtained: ∣gAeΓ—gAN3∣<1.9Γ—10βˆ’10| g_{Ae}\times g_{AN}^3|< 1.9\times 10^{-10} for 90\% C.L..Comment: 5 pages, 3 figures, Proceedings of the 10th Patras Workshop on Axions, WIMPs and WISP 29 June - 4 July 2014, CERN, Geneva, Switzerlan
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