LDA+DMFT Spectral Functions and Effective Electron Mass Enhancement in Superconductor LaFePO

In this Letter we report the first LDA+DMFT results (method combining Local Density Approximation with Dynamical Mean-Field Theory) for spectral properties of superconductor LaFePO. Calculated {\bf k}-resolved spectral functions reproduce recent angle-resolved photoemission spectroscopy (ARPES) data [D. H. Lu {\it et al}., Nature {\bf 455}, 81 (2008)]. Obtained effective electron mass enhancement values $m^{*}/m\approx$ 1.9 -- 2.2 are in good agreement with infrared and optical studies [M. M. Qazilbash {\it et al}., Nature Phys. {\bf 5}, 647 (2009)], de Haas--van Alphen, electrical resistivity, and electronic specific heat measurements results, that unambiguously evidence for moderate correlations strength in LaFePO. Similar values of $m^{*}/m$ were found in the other Fe-based superconductors with substantially different superconducting transition temperatures. Thus, the dynamical correlation effects are essential in the Fe-based superconductors, but the strength of electronic correlations does not determine the value of superconducting transition temperature.Comment: 4 pages, 3 figure

NiO: Correlated Bandstructure of a Charge-Transfer Insulator

The bandstructure of the prototypical charge-transfer insulator NiO is computed by using a combination of an {\it ab initio} bandstructure method and the dynamical mean-field theory with a quantum Monte-Carlo impurity solver. Employing a Hamiltonian which includes both Ni-d and O-p orbitals we find excellent agreement with the energy bands determined from angle-resolved photoemission spectroscopy. This solves a long-standing problem in solid state theory. Most notably we obtain the low-energy Zhang-Rice bands with strongly k-dependent orbital character discussed previously in the context of low-energy model theories.Comment: 4 pages, 3 figur

Effects of highly active antiretroviral therapy on the effectiveness of inpatient treatment of tuberculosis in patients with advanced stages of HIV infection

A prospective study of treatment outcomes of tuberculosis in 389 patients with advanced HIV infection with the initiation of HAART during the intensive phase of ТВ chemotherapy. HAART often prescribed ТВ and 4B advanced HIV infection. In the absence of HAART occurred generalization of tuberculosis. Patients receiving HAART were significantly more often dropped out of the hospital with a good result of treatment of tuberculosis and the cessation of bacterial isolation and significantly fewer were dying in hospital or at discharge had an unsatisfactory outcome of tuberculosis treatment. Side effects reported HAART one in ten patients and occurred 6.4 times more frequently than from taking anti-ТВ drugs. Cropped which developed side effects of HAART occurred within 1 to 2 months. Scheme of HAART as a result of established side effects of antiretroviral drugs infectious diseases had to change only in 2.9% of cases. In the treatment of tuberculosis in patients with advanced HIV infection, HAART should be necessary to appoint during the intensive phase of ТВ chemotherapy in association with infectious diseases physician in the first 2 months of monitored possibility of patient adverse reactions.Проведено проспективное исследование результатов лечения туберкулеза у 389 больных с поздними стадиями ВИЧ-инфекции с началом проведения ВАРТ в период интенсивной фазы химиотерапии туберкулеза. ВАРТ чаще назначали туберкулезом и 4В стадией ВИЧ-инфекцией. При отсутствии ВАРТ происходила генерализация туберкулеза. Пациенты, получавшие ВАРТ, достоверно чаще выбывали из стационара с хорошим результатом лечения туберкулеза и прекращением бактериовыделения и достоверно реже умирали в стационаре или имели при выписке неудовлетворительный результат лечения туберкулеза. Побочное действие ВАРТ зарегистрировано у каждого десятого пациента и возникало в 6,4 раза чаще, чем от приема противотуберкулезных препаратов. Купированние развившегося побочного действия ВАРТ происходило в течение 1-2-х месяцев. Схему ВАРТ в результате развившегося побочного действия антиретровирусных препаратов инфекционисту пришлось поменять только в 2,9% случаев. При лечении туберкулеза у больных с поздними стадиями ВИЧ-инфекции ВАРТ необходимо назначать в период проведения интенсивной фазы химиотерапии туберкулеза и совместно с врачом-инфекционистом в первые 2 месяца мониторировать возможность развития у больного побочных реакций

Underthreshold resonances in three-particle molecular systems

To determine the lifetimes of Efimov states of negative two-atomic ions, the problem of resonance scattering of a light particle on a pair of identical particles has been considered. An analytic expression has been obtained for resonance widths in the limit of forces of zero radius and low binding energies in pairs. Calculations are compared with the numerical solution of the Faddeev integral equations in a wide region of masses of the light particle. It is shown that the widths of underthreshold resonances in the scattering amplitude obtained from the integral equations with the Yamaguchi potential are well described by the analytic expression, which allows this expression to be used in the mass region inaccessible for numerical calculations. It has been concluded that the lifetime of highly excited negative molecular ions with a binding energy close to the threshold of disintegration is practically unlimited.Comment: Latex, 15 page

Correlation effects in Ni 3d states of LaNiPO

The electronic structure of the new superconducting material LaNiPO experimentally probed by soft X-ray spectroscopy and theoretically calculated by the combination of local density approximation with Dynamical Mean-Field Theory (LDA+DMFT) are compared herein. We have measured the Ni L2,3 X-ray emission (XES) and absorption (XAS) spectra which probe the occupied and unoccupied the Ni 3d states, respectively. In LaNiPO, the Ni 3d states are strongly renormalized by dynamical correlations and shifted about 1.5 eV lower in the valence band than the corresponding Fe 3d states in LaFeAsO. We further obtain a lower Hubbard band at -9 eV below the Fermi level in LaNiPO which bears striking resemblance to the lower Hubbard band in the correlated oxide NiO, while no such band is observed in LaFeAsO. These results are also supported by the intensity ratio between the transition metal L2 and L3 bands measured experimentally to be higher in LaNiPO than in LaFeAsO, indicating the presence of the stronger electron correlations in the Ni 3d states in LaNiPO in comparison with the Fe 3d states in LaFeAsO. These findings are in accordance with resonantly excited transition metal L3 X-ray emission spectra which probe occupied metal 3d-states and show the appearance of the lower Hubbard band in LaNiPO and NiO and its absence in LaFeAsO.Comment: 6 pages, 5 figure

Microwave-Assisted synthesis and evaluation of antibacterial activity of novel 6-fluoroaryl-[1,2,4]triazolo[1,5-A]pyrimidines

A series of 6-fluoroaryl substituted [1,2,4]triazolo[1,5-A]pyrimidines have been synthesized by using the microwave-Assisted Suzuki cross-coupling reaction from readily available 6-bromo-[1,2,4]triazolo[1,5-A]pyrimidine. The antimicrobial activity of new compounds has been evaluated in vitro against Mycobacterium tuberculosis H37Rv and gram-negative (Neisseria gonorrhoeae ATCC 49226) bacteria. © ARKAT-USA, Inc

Classification of the electronic correlation strength in the Fe-pnictides: The case of the parent compound BaFe2As2

Electronic correlations in the Fe-pnictide BaFe2As2 are explored within LDA+DMFT, the combination of density functional theory with dynamical mean-field theory. While the correlated band structure is substantially renormalized there is only little transfer of spectral weight. The computed k-integrated and k-resolved spectral functions are in good agreement with photoemission spectroscopy (PES) and angular resolved PES experiments. Making use of a general classification scheme for the strength of electronic correlations we conclude that BaFe2As2 is a moderately correlated system.Comment: 4 pages, 3 figure

CALCULATION OF CLINICAL AND ECONOMIC EFFICIENCY OF PROCEDURE OF ETIOLOGICAL DIAGNOSTICS OF TUBERCULOSIS

The article describes clinical (respective time of obtaining data on drug resistance) and economic (respective costs of reagents and consumables) efficiency of various procedures for etiological diagnostics of tuberculosis and prescription of chemotherapy regimens. The procedure developed and accepted by Ural Phthisiopulmonology Research Institute has been offered. According to this procedure costs of reagents and consumables when testing drug susceptibility to first and second line drugs for the patients with positive sputum tests makes about 5,000 RUR, time required for obtaining the results is 48 hours since delivery of the specimen to laboratory, time for confirmation of drug susceptibility pattern by culture is 30-40 days. For the patients with scanty bacillary excretion costs of reagents and consumables when testing drug susceptibility to first and second line drugs makes about 6,000 RUR, time required for obtaining the results is 8-14 days since delivery of the specimen to laboratory, time for confirmation of drug susceptibility profile by culture is 30-40 days. Additionally to development of rational testing procedures, the main ways to enhance efficiency of etiological diagnostics are to stop double testing, exclude excessive and non-diagnostics tests, thoroughly reject low quality specimens delivered to laboratory

LDA+DMFT Spectral Functions and Effective Electron Mass Enhancement in the Superconductor LaFePO

In this paper we report LDA+DMFT results (method combining local-density approximation with dynamical mean-field theory) for spectral properties of superconductor LaFePO. Calculated k -resolved spectral functions reproduce recent angle-resolved photoemission spectroscopy data. Obtained effective electron mass enhancement values m/≈1.9-2.2 are in good agreement with infrared and optical studies, de Haas-van Alphen, electrical resistivity, and electronic specific-heat measurements results that unambiguously evidence for moderate correlations strength in LaFePO. Similar values of m /m were found in the other Fe-based superconductors with substantially different superconducting transition temperatures. Thus, the dynamical correlation effects are essential in the Fe-based superconductors, but the strength of electronic correlations does not determine the value of superconducting transition temperature. © 2010 The American Physical Society