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The Tb3+ (4f 8) crystal-field (CF) excitations and the infrared phonons in TbMnO3 are studied as a function of temperature and under an applied magnetic field. The phonon energy shifts reflect local displacement of the oxygen ions that contribute to the CF energy level shifts below 120 K and under magnetic field. The CF polarized transmission spectra provide interesting information about the debated nature of the excitations at 41, 65, 130 cm-1. We also evaluate the contribution of the charge transfer mechanism to the magnetoelectric process in TbMnO3 under magnetic field.

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Electric manipulation of magnetic properties is a key problem of materials research. To fulfill the requirements of modern electronics, these processes must be shifted to high frequencies. In multiferroic materials, this may be achieved by electric and magnetic control of their fundamental excitations. Here we identify magnetic vibrations in multiferroic iron borates that are simultaneously sensitive to external electric and magnetic fields. Nearly 100% modulation of the terahertz radiation in an external field is demonstrated for SmFe_{3}(BO_{3})_{4}. High sensitivity can be explained by a modification of the spin orientation that controls the excitation conditions in multiferroic borates. These experiments demonstrate the possibility to alter terahertz magnetic properties of materials independently by external electric and magnetic fields.

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To date, percutaneous nephrolithotomy (PNL) is the standard treatment modality for large-volume renal stones and staghorn stones in patients with urolithiasis. Despite low invasiveness, this method is not without complications. This review discusses the most common complications and suggests methods for their prevention and appropriate management. To unify the study of complications they were categorized based on the modified Clavien classification. According to the available data, about 80% of the PNL complications belong to grade I-II complications and does not require any additional treatment. The most serious complications include sepsis, bleeding, and injury to nearby organs.

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INTRODUCTION: In recent years, there has been an increasing role of ureteroscopy in managing urinary tract calculi of various locations. Several studies have reported the relationship between the efficacy and safety of ureteroscopic interventions and surgeons skills and hospital caseload volume. The aim of our study was to assess the effectiveness of urethroscopic stone removal, the changes in treatment effectiveness, frequency and types of complications along with gaining experience in these interventions. MATERIALS AND METHODS: We analyzed 4031 urolithiasis patients who were admitted to our urological department and underwent ureteroscopy from 2001 to 2013. To determine the effectiveness and safety of the method, as the experience gained, the time of observation was divided into three periods: from 2000 to 2004, from 2004 to 2009, from 2009 to 2013. The parameters were evaluated for the entire observation time and for each period. RESULTS: Complete fragmentation of the stones was observed in 3628 (90%) patients, partial - in 219 (5.4%). No treatment effect was observed in 138 (3.4%) patients. The greatest effectiveness (96.94%) was seen in stones in the lower third of the ureter. The proportion of unsuccessful ureteroscopies was 5.7%, 4.5% and 3.5% for the periods 2000 -2004, 2005-2009 and 2009-2013, respectively (p=0.027). The incidence of acute postoperative pyelonephritis in the corresponding periods was 15.4%, 3.3% and 2.9% (p<0.001). CONCLUSION: Ureteroscopy is an effective and safe treatment modality for managing upper urinary tract calculi. It is most effective in treating distal ureteral stones. The increase in the treatment effectiveness and the reduction in the incidence of complications along with gaining experience, suggests that these interventions should be practiced mainly in urology centers specializing in the care of patients with urolithiasis.

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The purpose of the research is to study the gender aspects of the employment of adolescents, working in the time free from their study, and its impact on the livestyle and health, to assess the risks to health of students. There was studied the employment of senior pupils and students of vocational schools (1.2 thousand persons at the age from 14 till 18 years) in 5 regions of the Russian Federation. The results indicate to a prevalence of illegal employment of the minors. Among young men 62% work part time, among young women - 37%. Violations of hygienic requirements for working conditions and labor law violations are more common in young men employment. The first experience of work can render negative impact on the lifestyle and the state of health. In the working adolescents there is observed the higher prevalence of the behavioral risk factors (smoking, alcohol, drugs, sleep deprivation and others). Adolescents with work experience have lower health status. The analysis of odds ratio (OR), relative risk (RR), etiological fraction (EF) showed that to the higher health risk there are exposed teenagers working constantly throughout the year. In this group among girls there is a high prevalence of chronic diseases (RR = 2; OR = 3.9), of complaints of indigestion (RR = 2; OR = 2.5). In the group of young men, working continuously, the percentage of frequently ill with acute respiratory infections is higher (RR = 3.3; OR = 3.7), there is a higher number of complaints of heartburn (RR = 2.1; OR = 2.6), back pain (RR = 1.8; OR = 2.2). Working young men have higher health risk by comparison with working young women.

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Separating between the ordinary Hall effect and anomalous Hall effect in the paramagnetic phase of Mn_{1-x}Fe_{x}Si reveals an ordinary Hall effect sign inversion associated with the hidden quantum critical (QC) point x^{*}∼0.11. The effective hole doping at intermediate Fe content leads to verifiable predictions in the field of fermiology, magnetic interactions, and QC phenomena in Mn_{1-x}Fe_{x}Si. The change of electron and hole concentrations is considered as a "driving force" for tuning the QC regime in Mn_{1-x}Fe_{x}Si via modifying the Ruderman-Kittel-Kasuya-Yosida exchange interaction within the Heisenberg model of magnetism.

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In hexagonal DyMnO3, Dy(3+) crystal-field excitations are studied as a function of temperature and applied magnetic field. They are complemented with the measurements of infrared active phonon frequency shifts under applied magnetic field at T = 4.2 K. Between TN = 68 K and T = 10 K, the absence of Dy(3+) Kramers doublet splittings at either the C3 or the C3v site symmetries indicates that the Mn(3+) magnetic order effective exchange field has no component parallel to the c-axis at either site. Below T = 10 K, the ground state Kramers doublet splits under the Dy(3+) internal effective field as well as the applied magnetic field. Also, relatively strong infrared active phonon energy shifts are observed in magneto-infrared reflectance measurements at T = 4.2 K, allowing the calculation of the induced electric polarization changes as a function of the applied magnetic field. Such changes are associated with a large magnetoelectric effect in DyMnO3, arising from a charge transfer between Dy(3+) and apical oxygen ions.

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Dc-susceptibility measurements and Raman active phonon frequencies of hexagonal DyMnO(3) retrace the Mn(3+) ions antiferromagnetic transition at T(N) ~ 70 K and their spin reorientation at T(SR) ~ 48 K. The temperature evolution of Raman active mode frequencies and their over-hardening are associated with Dy(3+) and Mn(3+) ion displacements below T(N) and with a spin-phonon coupling that involves apical oxygen.

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We report on the optical spectroscopy of monolithic fiber preform prepared from nanoporous bismuth-doped silica glass. The experiments reveal the existence of at least two different types of active centers and clearly demonstrate that the presence in the glass matrix of other dopant is not necessary to obtain the near-IR photoluminescence connected to Bismuth.

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Terahertz electromagnetic excitations in the multiferroic TbMnO3 single crystals are investigated across the magnetic field induced rotation of the magnetic spin cycloid. In addition to the electromagnon along the a axis, the detailed polarization analysis of the experimental spectra suggests the existence of an electroactive excitation for ac electric fields of the electromagnetic wave along the crystallographic c axis. This excitation is possibly the electroactive eigenmode of the spin-cycloid in TbMnO3, which has been predicted within the inverse Dzyaloshinskii-Moriya mechanism of magnetoelectric coupling.

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The A(1), E(1) and E(2) Raman active modes in hexagonal YMnO(3) and LuMnO(3) single crystals are studied as a function of temperature and compared with previous measurements. In addition to anharmonicity, some phonon frequencies show below T(N) anomalous temperature dependences that reflect the atomic displacements while some other phonon frequencies are more sensitive to the spin-phonon coupling.

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We report on the observation of optically detected magnetic resonance (ODMR) in bismuth-doped silica glass. To explain the results of the experiment we adopted the intramolecular charge transfer model for Bi(5+)O(n)(2-) molecules in the frame of a semiempirical molecular orbitals approach. The results of our calculations are in good agreement with observed features of luminescence and ODMR experiments.

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We present a detailed dielectric study of the relaxation effects that occur in several perovskite rare-earth manganites, including the multiferroics TbMnO(3) and DyMnO(3). We demonstrate that the strong magnetocapacitive effects, observed for electrical fields E parallel c, are nearly completely governed by magnetic-state induced changes of the relaxation parameters. The multiferroic materials, which undergo a transition into a spiral magnetic state, show qualitatively different relaxation behavior than those compounds transferring into an A-type antiferromagnetic state. We ascribe the relaxations in both cases to the off-center motion of the manganese ions, which in the multiferroic systems also leads to the ferroelectric ordering.

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Magnetic and magnetoelectric excitations in the multiferroic TbMnO3 have been investigated at terahertz frequencies. Using different experimental geometries we can clearly separate the electroactive excitations (electromagnons) from the magnetoactive modes, i.e., antiferromagnetic resonances. Two antiferromagnetic resonances were found to coincide with electromagnons. This indicates that both excitations belong to the same mode and the electromagnons can be excited by a magnetic ac field as well. In spite of the 90 degrees rotation of the magnetic cycloid in external magnetic fields, the electromagnons are observable for electric ac fields parallel to the a axis only.

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We present a micro-Raman study of a high quality Pr(0.5)Ca(0.5)MnO(3) single crystal and thin films on SrTiO(3) and LaAlO(3) substrates. Ten A(g) and seven B(2g) Raman-active modes (simplified symmetry: Pmma space group) have been observed and correlated to charge ordering around T(co) = 240 K and antiferromagnetic spin-orbital ordering at T(N)∼ 170 K. Our data reveal that coherent Jahn-Teller MnO(6) distortions prevail at T