Enhanced superhyperfine structure of the EPR spectra of a U3+ ion introduced into the Van Vleck paramagnet LiTmF4

The observation of the superhyperfine structure (SHFS) in EPR spectra due to enhanced nuclear magnetism is reported. The X-band spectrum of a U 3+ ion introduced into the Van Vleck paramagnet LiTmF4 is measured in the temperature range of 5-20 K and compared with the spectra of LiLuF4:U3+ and LiYF4:U3+ single crystals. The spectra reveal well-resolved and strikingly different SHFS. The SHFS of Li(Lu, Y)F4:U3+ is due to the fluorine ions forming the nearest surroundings of the U3+ ion. The main contribution to the SHFS of the U3+ spectrum in LiTmF4 comes from the Tm3+ ions with a highly enhanced nuclear gyromagnetic tensor. © 2008 Pleiades Publishing, Ltd

Superhyperfine structure of the EPR spectra of Nd3+ and U3+ ions in LiRF4 (R = Y, Lu, Tm) double fluorides

The superhyperfine structure of the EPR spectra of impurity Nd3+ and U3+ ions in LiYF4, LiLuF4, and LiTmF4 double-fluoride single crystals has been observed and discussed. In LiYF4: Nd (g{pipe} = 1. 987, g⊥ = 2. 554) and LiTmF4: Nd, the superhyperfine structure is observed at the orientation of the external magnetic field B in parallel to the c axis of the crystals and consists of nine components with a splitting of ~15. 4 MHz. In LiYF4: U (g{pipe} = 1. 149, g⊥ = 2. 508) and LiLuF4: U, the superhyperfine structure is observed at both B {pipe} c and B ⊥ c and consists of nine and eleven components, respectively, with a splitting of ~21. 5MHz. It should be noted that the resolution of the superhyperfine structure of the EPR spectrum of LiLuF4: U3+ becomes significantly higher with a deviation from the orientation B ⊥ c. © 2011 Pleiades Publishing, Ltd

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The superhyperfine structure of the EPR spectra of impurity Nd3+ and U3+ ions in LiYF4, LiLuF4, and LiTmF4 double-fluoride single crystals has been observed and discussed. In LiYF4: Nd (g{pipe} = 1. 987, g⊥ = 2. 554) and LiTmF4: Nd, the superhyperfine structure is observed at the orientation of the external magnetic field B in parallel to the c axis of the crystals and consists of nine components with a splitting of ~15. 4 MHz. In LiYF4: U (g{pipe} = 1. 149, g⊥ = 2. 508) and LiLuF4: U, the superhyperfine structure is observed at both B {pipe} c and B ⊥ c and consists of nine and eleven components, respectively, with a splitting of ~21. 5MHz. It should be noted that the resolution of the superhyperfine structure of the EPR spectrum of LiLuF4: U3+ becomes significantly higher with a deviation from the orientation B ⊥ c. © 2011 Pleiades Publishing, Ltd

Superhyperfine structure of EPR spectra in LiLuF 4:U 3+ and LiYF 4:Yb 3+ single crystals

Electron paramagnetic resonance (EPR) spectra of doped paramagnetic crystals LiLuF 4:U 3+ and LiYF 4:Yb 3+ have been investigated at a frequency of about 9.42 GHz in the temperature range of 10-20 K. The U 3+ ion spectrum is characterized by g-factors g ∥ = 1.228 and g ⊥ = 2.516, and contains the hyperfine structure due to the 235U isotope with nuclear spin I = 7/2 and natural abundance of 0.71%. The observed hyperfine interaction constants are A ∥ = 81 G and A ⊥ = 83.8 G. Moreover, the spectrum reveals the well-resolved superhyperfine structure (SHFS) due to two groups of four fluorine ions forming the nearest surrounding of the U 3+ ion. This SHFS contains up to nine components with the spacing between components being about 12.7 G. The SHFS is observed also in the EPR spectrum of the LiYF 4:Yb 3+ crystal; up to 17 components with spacing of about 3.7 G may be traced. Some parameters of the effective Hamiltonian of the SHF interaction are estimated, the contribution of covalent bonding of f-electrons with ligands into these parameters is discussed. © 2008 Springer-Verlag

Superhyperfine structure of the EPR spectra of Ce3+ ions in LiRF4 (R = Y, Lu, Tm) double fluorides

The EPR spectra of Ce3+ impurity ions in LiYF4, LiLuF4, and LiTmF4 double-fluoride single crystals have been investigated at a frequency of ~9.3 GHz in the temperature range 5-25 K. The effective g factors of the ground Kramers doublet of the cerium ions in three crystals are close to each other (g{norm of matrix} = 2.737, g⊥ = 1.475 for LiYF4:Ce3+). A superhyperfine structure of the EPR spectrum of Ce3+ ions in the LiTmF4 Van Vleck paramagnet has been observed in the external magnetic field B oriented along the crystallographic axis c (B {norm of matrix} c). The superhyperfine structure of the EPR soectra of the Ce3+ ions in the LiYF4 and LiLuF4 diamagnetic matrices is resolved for B ⊥ c. Possible factors responsible for this pronounced difference in the properties of the systems studied have been discussed. © 2010 Pleiades Publishing, Ltd

Coulomb breakup of neutron-rich 29,30^{29,30}Na isotopes near the island of inversion

First results are reported on the ground state configurations of the neutron-rich $^{29,30}$Na isotopes, obtained via Coulomb dissociation (CD) measurements as a method of the direct probe. The invariant mass spectra of those nuclei have been obtained through measurement of the four-momentum of all decay products after Coulomb excitation on a $^{208}Pb$ target at energies of 400-430 MeV/nucleon using FRS-ALADIN-LAND setup at GSI, Darmstadt. Integrated Coulomb-dissociation cross-sections (CD) of 89 $(7)$ mb and 167 $(13)$ mb up to excitation energy of 10 MeV for one neutron removal from $^{29}$Na and $^{30}$Na respectively, have been extracted. The major part of one neutron removal, CD cross-sections of those nuclei populate core, in its' ground state. A comparison with the direct breakup model, suggests the predominant occupation of the valence neutron in the ground state of $^{29}$Na${(3/2^+)}$ and $^{30}$Na${(2^+)}$ is the $d$ orbital with small contribution in the $s$-orbital which are coupled with ground state of the core. The ground state configurations of these nuclei are as $^{28}$Na_{gs (1^+)\otimes\nu_{s,d} and $^{29}$Na$_{gs}(3/2^+)\otimes\nu_{ s,d}$, respectively. The ground state spin and parity of these nuclei, obtained from this experiment are in agreement with earlier reported values. The spectroscopic factors for the valence neutron occupying the $s$ and $d$ orbitals for these nuclei in the ground state have been extracted and reported for the first time. A comparison of the experimental findings with the shell model calculation using MCSM suggests a lower limit of around 4.3 MeV of the sd-pf shell gap in $^{30}$Na.Comment: Modified version of the manuscript is accepted for publication in Journal of Physics G, Jan., 201

Phage therapy in antibiotic resistant pneumonia: immunomodulation or redistribution?

Our report concerns the observations made during the treatment of pneumonia with individually selected bacteriophages in HCAI patients on mechanical ventilation. 19 patients on mechanical ventilation whose condition was complicated by antibiotic-resistant pneumonia were examined. The treatment of patients was supplemented with phage therapy, bacteriophages were selected individually for each patient, taking into account the microbial etiology of the disease (Pseudomonas aeruginosa, Кlebsiella pneumoniae, Acinetobacter baumanii). Immunophenotyping of blood lymphocytes was carried out using 2-3-parameter flow cytometry. The functional activity of blood leukocytes was assessed by their ability to produce IFNα and IFNγ during cultivation. The level of interferons production in supernatants collected after cultivation was quantitatively evaluated both by their concentration (ELISA, reagents from “Vector-Best-Europe”, Russia) and by their biological activity. Statistical processing of the results was carried out using the Statistica 6 program according to the nonparametric Mann-Whitney U-test. In the course of successful phage therapy with individually selected bacteriophages overcoming of lymphopenia (if there was one) and an increase in both the number and functional activity of peripheral blood lymphocytes in all patients with pneumonia observed are noted. The relationship between the microbial load (mono- or mixed infection, the number of CFU pathogens of pneumonia, the need for repeated courses of phage therapy) and the degree of deficiency in one or another subpopulation of lymphocytes was not detected. Activation of the immune system achieved after one course of phage therapy was maintained for at least 3 weeks after phage administration was discontinued

The influence of sea ice cover and Atlantic water advection on annual particle export north of Svalbard

The Arctic Ocean north of Svalbard has recently experienced large sea ice losses and the increasing prominence of Atlantic water (AW) advection. To investigate the impact of these ongoing changes on annual particle export, two moorings with sequential sediment traps were deployed in ice‐free and seasonally ice‐covered waters on the shelf north (NSv) and east (ESv) of Svalbard, collecting sinking particles nearly continuously from October 2017 to October 2018. Vertical export of particulate organic carbon (POC), total particulate matter (TPM), planktonic protists, chlorophyll a, and zooplankton fecal pellets were measured, and swimmers were quantified and identified. Combined with sensor data from the moorings, these time‐series measurements provided a first assessment of the factors influencing particle export in this region of the Arctic Ocean. Higher annual TPM and POC fluxes at the ice‐free NSv site were primarily driven by the advection of AW, higher grazing by large copepods, and a wind‐induced mixing event during winter. Higher diatom fluxes were observed during spring in the presence of sea ice at the ESv site. Along with sea ice cover, regional differences in AW advection and the seasonal presence of grazers played a prominent role in the biological carbon pump along the continental shelf off Svalbard

Epidemiology of drug-resistant tuberculosis among children and adolescents in South Africa, 2005-2010

OBJECTIVE : To describe the demographic and clinical characteristics of children and adolescents diagnosed with resistance to any anti-tuberculosis drug (drug-resistant tuberculosis; DR-TB) in South Africa. DESIGN : We retrospectively reviewed medical records of all children (<13 years) and adolescents (13 to <18 years) with DR-TB at specialty hospitals in four South African provinces from 2005 to 2010. RESULTS : During the review period, 774 children and adolescents (median age 11.3 years) were diagnosed with DR-TB at selected facilities. A high proportion of patients had a history of previous TB treatment (285/631; 45.2%), human immunodeficiency virus (HIV) infection (375/685; 54.7%), contact with a TB case (347/454; 76.4%), and smear-positive (443/729; 60.8%), cavitary (253/680, 38.7%) disease. Eighty-two per cent of patients with HIV infection received antiretroviral therapy. Of 626 patients diagnosed with multidrug-resistant TB (MDR-TB), 561 (89.6%) received a regimen consistent with national guidelines; the median length of treatment was 22 months (IQR 16-25). Among 400 patients with any DR-TB and a known outcome, 20.3% died during treatment. CONCLUSION : Pediatric DR-TB in these provinces is characterized by complex clinical features at diagnosis, with one in five children dying during treatment. History of previous treatment and contact with a TB patient indicate opportunities for earlier diagnosis and treatment to improve outcomes.U.S. Agency for International Development and U.S. Centers for Disease Control and Prevention, with additional support from the South Africa National Institute for Communicable Diseases and the South African Medical Research Council.http://www.ingentaconnect.comcontent/iuatld/ijtld2015-12-01hb201