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Living kidney donation is widely practiced throughout the world. During the past 2 decades, various groups have provided guidance about the evaluation and care of living donors. However, during this time, our knowledge in the field has advanced substantially and many agreed on the need for a comprehensive, unifying document. KDIGO (Kidney Disease: Improving Global Outcomes) addressed this issue at an international level with the publication of its clinical practice guideline on the evaluation and care of living kidney donors. The KDIGO work group extensively reviewed the available literature and wrote a series of guideline recommendations using various degrees of evidence when available. As has become recent practice, NKF-KDOQI (National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) convened a work group to provide a commentary on the KDIGO guideline, with a focus on how these recommendations apply in the context of the United States. In the United States, the United Network for Organ Sharing (UNOS) guides and regulates the practice of living kidney donation. While the KDIGO guideline for the care of living kidney donors and UNOS policy are similar in most aspects of the care of living kidney donors, several important areas are not consistent or do not align with common practice by US transplantation programs in areas in which UNOS has not set specific policy. For the time being, and recognizing the value of the KDIGO guidelines, US transplantation programs should continue to follow UNOS policy.

We observed the TeV blazar Mrk421 in the very high energy (VHE) region with TACTIC from 21 December, 2014 to 21 February, 2015. The VHE γ-ray signal is detected from the source at a statistical significance of ∼ 9σ with 648 ± 74 γ-ray like events using a total observation time of 65.6 h of clean data. To denote the active period of the source, the entire observation has been divided into two spells: Spell I (21–30 December, 2014; MJD: 57012–57021) and Spell II (15 January-21 February, 2015; MJD: 57037–57074). The Spell I corresponds to relatively higher activity state wherein 337 ± 47 γ-rays are detected at a statistical significance of 7.39σ in 21.7 h. During Spell II, 311 ± 57 γ-ray events have been detected in ∼ 44c at a statistical significance of 5.6σ. The analysis of high energy (HE) γ-ray data from Fermi-LAT has been carried out for the period of TACTIC observations. In addition, near simultaneous multi-wavelength data from Swift-BAT and MAXI in the X-ray region, SPOL in optical V-band and OVRO at 15 GHz radio band have also been considered. The HE γ-ray and optical observations indicate variability during both the spells whereas hard X-ray observations are consistent with the average emission through out the TACTIC observations. The broad-band spectral energy distributions of the source are reproduced by single zone homogeneous synchrotron self Compton process for the two spells. The model parameters estimated for the two spells are similar except for the particle energy density which is obtained to be slightly higher during Spell I.

Non-blazar active galactic nuclei like radio galaxies have emerged as a new class of γ-ray sources in the sky. Observations of very high energy (VHE) γ-rays from radio galaxies with misaligned jets offer a unique tool to understand the physical processes involved in these type of objects. In this work, we present the results of our observations of the nearby peculiar radio galaxy IC 310 (z = 0.0189) with TACTIC telescope for nearly 95.5 hours from 03 December, 2012 to 19 January, 2015 (MJD 56265 - 57041). Detailed analysis of the data reveals absence of a statistically significant γ-ray signal from the source direction (both on the overall period and on yearly basis). Our results suggest that the source was possibly in a low-TeV emission state (below the TACTIC sensitivity level) during the above mentioned observation period and the resulting 3σ upper limit on the integral flux above 850 GeV has been estimated to be 4.99 × 10 − 12 ph cm − 2 s − 1 (23% of the Crab Nebula flux). Analysis of the contemporaneous data collected by Fermi-LAT in the 30 – 300 GeV energy range, also indicate the absence of a statistically significant γ-ray signal, therefore 2σ upper limit on the integral flux above 30 GeV has been estimated on yearly basis. We also report the results from dedicated optical observations in B, V and R bands from ARIES observatory carried out from December, 2014 to March, 2015.

In its application to the modeling of a mineral separation process, we propose the numerical analysis of the Cahn-Hilliard equation by employing space-time discretizations of the automatic variationally stable finite element (AVS-FE) method. The AVS-FE method is a Petrov-Galerkin method which employs the concept of optimal discontinuous test functions of the discontinuous Petrov-Galerkin (DPG) method by Demkowicz and Gopalakrishnan. The trial space, however, consists of globally continuous Hilbert spaces such as H 1 ( Ω ) and H ( div , Ω ) . Hence, the AVS-FE approximations employ classical C 0 or Raviart-Thomas FE basis functions. The optimal test functions guarantee the numerical stability of the AVS-FE method and lead to discrete systems that are symmetric and positive definite. Hence, the AVS-FE method can solve the Cahn-Hilliard equation in both space and time without a restrictive CFL condition to dictate the space-time element size. We present multiple numerical verifications of both stationary and transient problems. The verifications show optimal rates of convergence in L 2 ( Ω ) and H 1 ( Ω ) norms. Results for mesh adaptive refinements in both space and time using a built-in error estimator of the AVS-FE method are also presented.

Magnetocaloric properties of La1−xKxMnO3 (x = 0.11, 0.13, 0.15) manganites and their two and three layer composite structures are measured under low and high magnetic fields by the direct method. The relative cooling power (RCP) in composites is revealed to increase by 20–40% in moderate magnetic fields of 20 kOe compared with parent materials. The value of the magnetic field, at which the greatest increase in RCP of the composite takes place, depends on the proximity of Curie temperatures of the materials composing the structure; for the studied materials a maximum increase in the RCP is observed in the magnetic field range from 40 to 50 kOe.

We have observed Markarian 501 in Very High Energy (VHE) gamma-ray wavelength band for 70.6 hours from 15 April to 30 May, 2012 using TACTIC telescope. Detailed analysis of $\sim$66.3 hours of clean data revealed the presence of a TeV $\gamma$-ray signal (686$\pm$77 $\gamma$-ray events) from the source direction with a statistical significance of 8.89$\sigma$ above 850 GeV. Further, a total of 375 $\pm$ 47 $\gamma$-ray like events were detected in 25.2 hours of observation from 22 - 27 May, 2012 with a statistical significance of 8.05$\sigma$ indicating that the source has possibly switched over to a relatively high gamma-ray emission state. We have derived time-averaged differential energy spectrum of the state in the energy range 850 GeV - 17.24 TeV which fits well with a power law function of the form $dF/dE=f_{0}E^{-\Gamma}$ with $f_{0}= (2.27 \pm 0.38) \times 10 ^{-11} $ photons cm$^{-2}$ s$^{-1}$ TeV$^{-1}$ and $\Gamma=2.57 \pm 0.15$. In order to investigate the source state, we have also used almost simultaneous multiwavelength observations viz: high energy data collected by $\it{Fermi}$-LAT, X-ray data collected by $\it{Swift}$-XRT and MAXI, optical and UV data collected by $\it{Swift}$-UVOT, and radio data collected by OVRO, and reconstructed broad-band Spectral Energy Distribution (SED). The obtained SED supports leptonic model (homogeneous single zone) for VHE gamma-ray emission involving synchrotron and synchrotron self Compton (SSC) processes., Comment: 10

The nearby ( z = 0.031 ) TeV γ-ray emitter BL Lac object Mrk 421 has been observed with the TACTIC telescope for nearly 118 hours during 01 February to 26 April, 2012 (MJD 55958–56044). Detailed analysis reveals the detection of 529 ± 76 γ-rays with 6.9σ significance above 850 GeV energy threshold during the period of 15–26 March, 2012 (MJD 56001–56013). Nearly simultaneous multiwavelength observations of the source also indicate a comparatively higher flux state during this period (MJD 56001–56013). In this paper, we present the study of Mrk 421 during this period in very high energy (VHE) domain along with the results from high energy (HE), X-ray, optical and radio observations. We reproduce the spectral energy distribution (SED) of the source during this period using the synchrotron and synchrotron self-Compton (SSC) process. The model parameters of the emission region of the source are found to be consistent with the values reported in the literature.

Donor-derived coccidioidomycosis has caused unexpected morbidity and mortality in transplant recipients. All proven or probable reports of donor-derived coccidioidomycosis to the Disease Transmission Advisory Committee between 2005 and August 2012 were reviewed. Six reports of proven or probable coccidioidomycosis were discovered. In four of six, the infection was first detected at autopsy in the recipient. In two cases it was first identified in the donor. Twenty-one recipients received organs from these six donors. Transmission occurred in 43% at a median of 30 days posttransplant with a mortality rate of 28.5%. Eleven recipients received preemptive antifungals, seven did not receive treatment, and treatment information was not reported for three recipients. Five of seven who did not receive prophylaxis/treatment died and all 11 who received early therapy survived. Six deaths occurred 14 to 55 days after transplant, with a median of 21 days. For exposed recipients, donor-derived coccidioidomycosis is a significant cause of morbidity and mortality. Evidence of infection in one recipient should prompt immediate evaluation for treatment of all other recipients from the same donor as preemptive treatment was effective. Further studies are needed to decide whether all donors from endemic areas should have routine serologic screening.

A complex permittivity at a low level of excitation signal was measured in ceramic LuFe 2 O 4 . A Debye-type relaxation response with a strong temperature dependence of a characteristic frequency was observed in accordance with earlier works. A small DC bias of about 10 V/cm led to unusual changes in the dielectric response. At frequencies, which were lower than the characteristic one, the conductivity drastically increased with slight decrease of the real part of the permittivity under the bias. In the opposite case of low frequencies, there are no traces of the DC bias effect. We show that an inhomogeneous charge distribution over surface layer (domain structure) is essential for describing the biased dielectric response in LuFe 2 O 4 .

Chemical solution deposition of smooth amorphous Al 2 O 3 thin films has been successfully used for planarization of long-length metallic substrates for 2G HTS superconducting wires production. A series of metal-organic precursors based on Al( i PrO) 3 , Al(acac) 3 , acetic acid, monoethanolamine (MEA) and diethylenetriamine (DETA) was developed. Correlations between the precursor composition and the features of its two-step thermal-induced transformation to amorphous Al 2 O 3 were studied by 1 H NMR, IR spectroscopy and thermal analysis. Utilizing the solutions of {Al( i PrO) 3 + 2.5MEA + 6HAcet} in i PrOH and {Al(acac) 3 + nDETA} in HAcet (n = 1 − 3) as precursors for dip-coating, we obtained the long-length Hastelloy C276 substrate covered by uniform amorphous 50–550 nm thick alumina films with surface roughness of about 0.5–1.5 nm. A 20 m long sample of 2G HTS wire with a commercial level of superconducting critical current of up to 300 A was prepared based on Hastelloy substrate tape planarized with Al 2 O 3 .

Epitaxial VO2 films on r-sapphire substrates with ideal composition, dense structure and superior functional properties were obtained by water-assisted MOCVD from vanadyl hexafluoroacetylacetonate followed by the annealing under optimized conditions. The obtained films exhibit both intense optical switch properties in IR region and unique MIT characteristics: change in resistance by 4.6 orders in the temperature range 40–80 °C, hysteresis width less 0.7 °C and transition width 1.5 °C. The proposed synthetic approach opens new opportunities to fabricate highly sensitive and ultrafast switches for optical, electronic and biomedical devices.

Epitaxial thin films of granular and layered nanocomposites consisting of ferromagnetic perovskite Pr1–xSrxMnO3 and ferroelectric hexagonal LuMnO3 were grown on ZrO2(Y2O3) substrates using metal-organic chemical vapor deposition (MOCVD). A self-organized growth of the granular composite took place in situ as a result of phase separation of the Pr–Sr–Lu–Mn–O system into the perovskite and hexagonal phases. Optical transmission measurements revealed a large negative magnetotransmission effect in the layered nanocomposite over a wide spectral and temperature range. The granular nanocomposite unexpectedly showed an even larger, but positive, magnetotransmission effect at room temperature.

In this paper, we present results of TeV $\gamma$--ray observations of the high synchrotron peaked BL Lac object 1ES 1218+304 (z=0.182) with the $TACTIC$ (TeV Atmospheric Cherenkov Telescope with Imaging Camera). The observations are primarily motivated by the unusually hard GeV-TeV spectrum of the source despite its relatively large redshift. The source is observed in the TeV energy range with the $TACTIC$ from March 1, 2013 to April 15, 2013 (MJD 56352--56397) for a total observation time of 39.62 h and no evidence of TeV $\gamma$--ray activity is found from the source. The corresponding 99$\%$ confidence level upper limit on the integral flux above a threshold energy of 1.1 TeV is estimated to be 3.41 $\times10^{-12}$ photons cm$^{-2}$ s$^{-1}$ (i.e $, Comment: Accepted for Publication in New Astronomy

We describe two cases of donor-derived methicillin-resistant Staphylococcus aureus (MRSA) bacteremia that developed after transplantation of organs from a common donor who died from acute MRSA endocarditis. Both recipients developed recurrent MRSA infection despite appropriate antibiotic therapy, and required prolonged hospitalization and hospital readmission. Comparison of S. aureus whole genome sequence of DNA extracted from fixed donor tissue and recipients’ isolates confirmed donor-derived transmission. Current guidelines emphasize the risk posed by donors with bacteremia from multidrug-resistant organisms. This investigation suggests that, particularly in the setting of donor endocarditis, even a standard course of prophylactic antibiotics may not be sufficient to prevent donor-derived infection.

Thin epitaxial La 1− х K х MnO 3 films were grown using two-stage procedure. Influence of substitution of La 3+ ions with K + ions on the optical and electrical properties of La 1− x K x MnO 3 films ( х =0.05, 0.10, 0.15 и 0.18) has been studied in detail. A noticeable magnetorefractive effect in the films under study was detected in the infrared range. Magnetorefractive effect as well as transverse magneto-optical Kerr effect and magnetoresistance have the maximum in optimally doped sample with x =0.18 corresponding to the highest Curie temperature. The experimental data for compositions close to optimally doped films are in good agreement with the data calculated in the framework of a theory developed for manganites. The resonance-like contribution to magnetoreflection spectra of manganite films has been observed in the vicinity of the phonon bands. It is shown that magnetic and charge inhomogeneities strongly influence on the magneto-optical effects in films. Thin films of La 1− x K x MnO 3 with the large values of Kerr and magnetorefractive effect are promising magneto-optical material in the infrared range.

In February 2013, the Organ Procurement and Transplantation Network mandated that transplant centers perform screening of living kidney donors prior to transplantation for Strongyloides, Trypanosoma cruzi and West Nile virus (WNV) infection if the donor is from an endemic area. However, specific guidelines for screening were not provided, such as the optimal testing modalities, timing of screening prior to donation and the appropriate selection of donors. In this regard, the American Society of Transplantation Infectious Diseases Community of Practice, together with disease-specific experts, has developed this viewpoint document to provide guidance for the testing of live donors for Strongyloides, T. cruzi and WNV infection, specifically identifying at-risk populations and testing algorithms, including advantages, limitations and interpretation of results.

Transplant candidates who accept a kidney labeled increased risk for disease transmission (IRD) accept a low risk of window period infection, yet those who decline must wait for another offer that might harbor other risks or never even come. To characterize survival benefit of accepting IRD kidneys, we used 2010–2014 SRTR data to identify 104,998 adult transplant candidates who were offered IRD kidneys that were eventually accepted by someone; the median (IQR) KDPI of these kidneys was 30 (16–49). We followed patients from the offer decision until death or end-of-study. After 5 years, only 31.0% of candidates who declined IRDs later received non-IRD DDKTs; the median KDPI of these non-IRD kidneys was 52, compared to 21 of the IRDs they had declined. After a brief risk period in the first 30 days following IRD acceptance [aHR accept vs decline: (1.22)2.06(3.49), p=0.008] (absolute mortality 0.8% vs. 0.4%), those who accepted IRDs were at 33% lower risk of death 1–6 months post-decision [aHR (0.50)0.67(0.90), p=0.006], and at 48% lower risk of death beyond 6 months post-decision [aHR (0.46)0.52(0.58), p

The design, development and operational characteristics of a compact corona pre-ionized helium-free TEA CO2 laser is discussed. Remarkably high efficiency of about 19% was obtained in this laser, which is attributed to the optimum concentration of CO2 and N2 gas, reduction in energy dissipation in the pre-ionization loop and the switch, minimizing the diffraction losses and finally optimization of the output coupler reflectivity. The helium-free TEA CO2 laser has also been analysed using a comprehensive theoretical model, developed based on the Boltzmann transport equations and the discharge excitation circuit equations. The voltage and current waveforms of the pulsed discharge were simulated and used as input to the laser rate equations to estimate the laser pulse energies and the pulse shapes. The theoretical estimations of the laser pulse energy agree fairly well with the experimental results. The accuracy of our theoretical model becomes evident from the numerically evaluated laser pulse shapes, which show remarkable resemblance with the experimentally measured pulse shapes. A detailed comparison with the helium-rich case is included to highlight the key aspects of a suitably designed helium-free TEA laser.

The Solution Deposition Planarization method was successfully used for smoothing Ni-alloy tapes with initial surface roughness of 26.7 nm (on 40×40 μm 2 area) and 12.6 nm (on 5×5 μm 2 area). New precursor solutions were prepared from yttrium acetate and diethylenetriamine or ethylenediamine in MeOH and i-PrOH—alcohols with different viscosities. Using those solutions yttria films with the residual roughness Sa=0.4 nm (on 5×5 μm 2 area) and Sa=7.6 nm (on 40×40 μm 2 area) were deposited on the Ni-alloy tapes.

Thin (80–800 nm) epitaxial silicon films on sapphire substrates were deposited via CVD technique and studied with XRD, SEM, EDS, EBSD, HRTEM and AFM methods. Increase of grain size, reduction of microtwin concentration and strong sharpening of crystallographic texture with increasing film thickness was observed. To our knowledge, XRD texture analysis in relation to film thickness of silicon on sapphire samples was performed for the first time. Thickness-dependent behavior of texture quality and film microstructure can be explained by the model of evolutionary selection and disclination formation.

In this article we summarize our results on the fabrication process of the Ni-Cr-W biaxially textured tape, which is non-magnetic at 77 K. The deposition processes of the buffer and HTS layers by reel-to-reel MOCVD technology are described as well. The HTS wire is finished with reel-to-reel depositions of the silver protective layer by magnetron sputtering and copper stabilizing layer by electroplating. Sharp cubic texture with in-plane and out-of-plane misorientation below 7 degrees and low surface roughness (Ra < 5 nm on 5*5 μm2 area) have been achieved on reel-to-reel processed metallic tapes. The texture characteristics of the MgO buffer layer (ΔωRD = 6.0̊, ΔωTD = 9.0̊, ΔφTRUE = 5.2̊) have been found to be very close to those of the textured substrate tape. Using this structure with additional buffer layers we have succeeded in growing superconducting YBCO coatings with Ic (77 K, s.f.) values higher than 120 A per cm of the tape width at the HTS layer thickness of about 1 μm.

Temperature and frequency dependencies of the real (χ′) and imaginary (χ″) parts of the dynamic magnetic susceptibility were studied experimentally in fine particles of La–Ag manganites prepared by various methods. The samples under study have the Curie points in the range TC=42–48 °C, which is a medical hyperthermia range of interest. When approaching TC from below, a critical peak of χ″ was revealed, followed by a steep drop while passing to the paramagnetic phase. The experiments on the magnetic radio-frequency (RF) heating of the manganite aqueous suspensions demonstrated good autostabilization of the temperature near TC. Peculiar instability is found in the heating kinetics, caused by the observed critical behavior of the RF losses. The prospects of the La–Ag manganites as candidates for application in the temperature-controlled hyperthermia are discussed.

We report here the preparation and properties of La 1 − x Ag y MnO 3 + δ thin epitaxial films. The original two-step preparation procedure was developed. At first, La 1 − x MnO 3 + δ were grown epitaxially by metal–organic chemical vapor deposition on the single-crystal substrates (001) and (110) SrTiO 3 , (001) LaAlO 3 , (111) and (001) ZrO 2 (Y 2 O 3 ). Treatment by the vapor of the metallic silver in the oxygen atmosphere (at 1 bar and 20 bar) was the second step resulting in the selective absorption of silver by La 1 − x MnO 3 + δ phase. The value of y depended on the process conditions and revealed different kinetics of the silver absorption for (001) and (110) orientation of La 1 − x MnO 3 + δ films. The films prepared were characterized by X-ray diffraction, scanning electron microscopy with energy-dispersion X-ray analysis, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, electrical resistivity and magnetoresistance measurements in a four-probe configuration. We have found that metal-insulator transition temperature ( T p ) in the series La 1 − x Ag x MnO 3 + δ possessed a maximum of 380 K at x = 0.15. Thus, T p of La 1 − x Ag x MnO 3 + δ films was significantly higher than ever reported in the literature for the La 1 − x Ag x MnO 3 + δ ceramics. La 1 − x Ag x MnO 3 + δ films demonstrated the important role of the ferromagnetic fluctuations above Curie temperature T c resulting in the sign change of the resistivity curve temperature slope d R / d T and a significant shift of T p well above T c . The maximum of the magnetoresistance on the temperature scale was close to d R / d T maximum. The intrinsic magnetoresistance values as high as 22% at 310 K and 50% at 280 K were measured in the magnetic field of 1 T in the series of La 1 − x Ag y MnO 3 + δ epitaxial films.

BiFeO 3 thin films were grown by metal organic chemical vapour deposition (MOCVD) at the temperature T=700 °C using Fe(thd) 3 , Bi (C 6 H 5 ) 3 as volatile precursors. High thermal stability of Bi(C 6 H 5 ) 3 makes the film stoichiometry very sensible to the deposition conditions, in particular to the precursor residence time in the reactor. We tested novel precursors Bi(thd) 3 and Bi(CH 3 COO) 3 possessing lower thermal stability. They drive the process into the diffusion control regime when cation stoichiometry in the layer is easier to control. The possibility to use them for epitaxial growth of BiFeO 3 thin films was demonstrated. BiFeO 3 film forms the self-organized nanodomain variant structure with (110) out-of-plane orientation on (001) ZrO 2 (Y 2 O 3 ) substrate. The high resolution TEM images confirm variant domain structure formation. The ferroelectric nature of BiFeO 3 films was assessed at the room temperature by piezoelectric force microscopy (PFM).

Giant volume magnetostriction, reached ∼6×10 −4 in magnetic field 8.2 kOe, is found in La 1− x M x MnO 3 (M=Ba, Sr, Ca, Ag) manganites near Curie-point T C . Volume magnetostriction ω and magnetoresistance exhibit similar dependence on temperature and magnetic field in T C region that is explained by the presence in these compounds of magnetic two-phase ferromagnetic–antiferromagnetic state due to strong s−d and/or d−d exchange. Maximum | ω |-value depends from radius of M-cation: it is larger the larger the difference | R A − R La3+ | and A-cation size variance σ 2 , where A=La 1− x M x .

We demonstrate that the colossal magnetoresistance (CMR) manganites doped with the monovalent cations of the large ionic radius A (A = Na+, K+, Ag+) reveal enhanced sensitivity of the electrical resistance to the magnetic field near the room temperature. The main obstacle to their practical application is severe difficulty of the synthesis, in particular, that of the thin films because of the high volatility or low thermal stability of the oxides of these doping elements. But the preparation of the films in two steps allows for the materials with the superior CMR characteristics. At the first step, epitaxial single phase precursor La1−xAyMnO3 (0.3 ≥ x > y) is formed on the single crystal substrate due to the epitaxial stabilization by the single source MOCVD (metalorganic chemical vapor deposition) using thd-complexes. The second step is the isopiestic annealing with the powder mixture determining the high concentration of the volatile oxide in the gas phase resulting in the saturation of La1−xAxMnO3 (x = y) films by the gas phase transport. The film transformations are studied with XRD and HREM. The high magnetoresistance MR and magnetotransmission MT with the linear magnetic field (H) dependence near the room temperature (dMR/dH up to 45%/T, dMT/dH up to 15%/T) are reported.

Rapid thermal MOCVD technique was adopted and applied for growing epitaxial films of BaTiO 3 on MgO substrates. A detailed description of modified experimental set-up design is given. Major modifications are towards optimizing the sources and gas lines. A new barium metal-organic precursor was developed on the basis of mixed ligand complexes of barium β-diketonates. Testing procedures showed that the developed precursor offers the advantages of low melting temperature, good volatility and ease of synthesis and handling. Grown layers were characterized by low and high resolution X-ray diffraction, scanning electron microscopy (SEM), and energy dispersive spectrometry in SEM in order to obtain information on structural quality, surface morphology and composition.

BiFeO 3 thin films were grown on (001) SrTiO 3 and (001) ZrO 2 (Y 2 O 3 ) substrates by single source metalorganic chemical vapor deposition in the temperature range T=500÷800 °C using Fe(thd) 3 and Bi(C 6 H 5 ) 3 as volatile precursors. X-ray diffraction analysis shows cube-on-cube epitaxial growth of BiFeO 3 on (001) SrTiO 3 . The strongly reduced bismuth transfer into the film due to the high thermal stability of Bi(C 6 H 5 ) 3 was counterbalanced by the increase of the total pressure as well as of the residence time of the precursor flow in the reactor; the Bi/Fe ratio in the film thus becomes close to that in the precursor mixture. Optical second harmonic generation measurements have evidenced the ferroelectric ordering in BiFeO 3 films and the apparent decrease of the Curie temperature of the strained films as compared to BiFeO 3 single crystal.

The temperature dependencies of the specific heat, thermal diffusivity and thermal conductivity in polycrystalline Nd 0.55 Sr 0.45 MnO 3 and Nd 0.5 Sr 0.5 MnO 3 manganites are measured in wide temperature range of 77–300 K. These characteristics reveal peculiarities at magnetic phase transition and transition into charge-ordered (CO) state. It is shown that a change of the phonon spectrum due to lattice contraction is the main reason of a sharp decrease of the thermal conductivity in Nd 0.5 Sr 0.5 MnO 3 at the transition to the antiferromagnetic CO state. Using the experimental thermal diffusivity data and sound velocity data a temperature dependency of the phonon mean free path is calculated.

The 139 La NMR spectra and spin–spin relaxation times have been measured for the 16 O and 18 O isotope-substituted manganite (La 0.25 Pr 0.75 ) 0.7 Ca 0.3 MnO 3 in the external magnetic field of 5 T. The NMR signal wipe-out has been observed in the 18 O-enriched sample in the charge-ordered state. This phenomenon is connected with a sharp increase in the spin–spin relaxation rate. The great isotope-effect observed provides a clear evidence of an essential role of oxygen motion in controlling the long-range magnetic order in manganites.

The measurements of temperature dependence of electrical resistivity ρ ( T ) and magnetic susceptibility χ ( T ) as well as neutron diffraction studies were performed for three groups of R 1 - x Sr x MnO 3 manganites. Each group was characterized by the same average ionic radius 〈 r A 〉 of rare earth R, but by different degree of cation disorder σ 2 = x i r i 2 - 〈 r A 〉 2 . For each composition, the isotope-substituted samples ( O 16 → O 18 ) were also prepared. It was shown that the increase in σ 2 at fixed 〈 r A 〉 leads to appreciable changes in electrical and magnetic properties, as well as to a more pronounced isotope effect. Large values of σ 2 give rise to a significant scatter in the values of the electron hopping integral for neighboring Mn sites. This favors the electron localization and the tendency to antiferromagnetism in the phase-separated state, thus enhancing the effect of oxygen isotope substitution.

We have investigated the effect of oxygen isotope substitution on the metal-insulator transition temperature and the resistivity of the narrow band manganite (La0.25Pr0.75)0.7Ca0.3MnO3 in a constant magnetic field. A set of 16 samples having different mixtures of 16O, 17O and 18O isotopes with average mass varying from 16.0 to 17.8 a.m.u. was studied. We have found that the magnetoresistance and the isotope effect can be linked together with a single parameter - effective magnetic field, which decreases linearly with an increase of average oxygen mass with a slope of -2 T/a.m.u. The applicability of the small polaron model is discussed., Comment: Submitted to Moscow International Symposium on Magnetism MISM'05

Here we report the expansion of the Ga 2 O 3 solubility range in ZnO films grown by MOCVD on single-crystal substrates due to the epitaxial stabilization contribution. The epitaxial relations were characterized for ZnO and a broad spectrum of the substrates including c- and r-Al 2 O 3 , (111) ZrO 2 (Y 2 O 3 ), (111) SrTiO 3 , (111) Gd 3 Ga 5 O 12 , (111) MgO, (111) MgAl 2 O 4 . First, the deposition kinetics was measured in the range 300–800 ∘ C using Zn(acac) 2 and Ga(acac) 3 , where acac = the acetylacetonate-anion. The maximum deposition rate corresponds to the range 500–550 ∘ C. The particular feature of the deposition process is switching to the growth of whiskers with the increase of the deposition rate. The films on (111) ZrO 2 (Y 2 O 3 ), (111) SrTiO 3 , are characterized by a higher epitaxial quality than films on sapphire traditionally used for ZnO epitaxy. This results in the higher solubility of Ga 2 O 3 in ZnO films on (111) ZrO 2 (Y 2 O 3 ) (at least up to 7.5 at.% Ga in the sum of Ga and Zn) as compared to the films on r-Al 2 O 3 (below 3 at.% Ga) due to the epitaxial stabilization. The intensity of the UV photoluminescence (PL) correlates with the epitaxial quality of ZnO films. Ga-doping resulted in the quenching of green PL band because of Ga 3+ occupancy of the octahedral interstitials in the ZnO structure (in agreement with the variation of the ZnO(Ga 2 O 3 ) lattice parameters).

The effect of 16 O→ 18 O isotope substitution on the electrical resistance and magnetic susceptibility of nearly half-doped R 1− x Sr x MnO 3 manganites was studied for ceramic samples with R=Sm ( x = 0.425 – 0.525 ), NdTb and NdEu ( x = 0.45 ). In these compounds, x = 0.5 is a critical doping level for the crossover between ferromagnetic (FM) metal and A-type antiferromagnetic (AFM) insulator. It was demonstrated that the oxygen isotope substitution drastically affects the phase diagram of the studied manganites favoring their enhanced inhomogeneity, stabilizing the insulating AFM state, and even causing the metal–insulator transition (MIT). This suggests that such a MIT is closely related to the FM–AFM crossover independent of the specific nature of magnetic state in manganites.

We have found that single-crystal substrates of ZrO 2 (Y 2 O 3 ) with (0 0 1) and (1 1 1) orientation are suitable for the growth of (1 1 0) perovskite films of La 0.7 Ca 0.3 MnO 3 , La 0.7 Sr 0.3 MnO 3 and La 1− x MnO 3 ( x =0.1–0.25) with the in-plane variant structure. The orientation types and crystallographic domains were determined by X-ray diffraction and high-resolution TEM. Special high-angle boundaries formed between the nanodomains of the epitaxial variants result in the high tunnel magnetoresistance (above 15% at 77 K and 0.1 T). The magnetic reversal transition was also detected in the field below 0.01 T, the sharpness of the transition was found to be very sensitive to the film microstructure. Further enhancement of the magnetoresistance was achieved in the heterostructures including perovskite manganite and ferrimagnetic insulating oxide layers.

A generalized ray-tracing procedure has been developed, which facilitates the design of a multimirror-based light collector used in atmospheric Cherenkov telescopes. This procedure has been employe ...

Our experiments on the preparation of the composites of CMR manganites and metal silver have shown that in the case of La 1− x MnO 3+ δ the vacancies in the A-sublattice of the perovskite structure can be filled by Ag + ions under the soft conditions of the synthesis. Neutron diffraction refinement of La 0.8 Ag 0.2 MnO 3.00 clearly proves the silver doping in the A-sublattice. Depending on P (O 2 )– T synthesis conditions the solid solutions with the broad stoichiometry range La 1− x Ag y MnO 3+ δ (0.3 ≥ x ≥ y ) were prepared. We report here the evolution of the oxygen stoichiometry, the crystal structure as well as electro-physical properties in the series of the solid solutions. Curie temperature comes over a maximum exceeding the room temperature with the increase of silver content. La 1− x Ag y MnO 3+ δ solid solutions can be useful for the construction of the room temperature magnetic field sensors based on the magnetoresistance effect.

An interrupt-based multinode data acquisition and control system has been developed for the imaging element of the TACTIC γ-ray telescope. The system which has been designed around a 3-node network of PCs running the QNX real-time operating system, provides single-point control with elaborate GUI facilities for operating the multi-pixel camera of the telescope. In addition to acquiring data from the 349-pixel photomultiplier tube based imaging camera in real time, the system also provides continuous monitoring and control of several vital parameters of the telescope for ensuring the quality of the data. The paper describes the salient features of the hardware and software of the data acquisition and control system of the telescope.

Nd 1− x Sm x NiO 3− δ ceramics were studied by means of XRD, iodometric titration, DSC and resistivity measurements. The metal-insulator transition for all compositions was studied by two independent procedures: resistivity and DSC measurements. The reason for differences in transition temperatures, defined by these two techniques is discussed. It was shown that these materials are promising for practical applications in bolometric devices due to high values of temperature coefficient of resistivity at room temperature.

The rare-earth nickelates are among few perovskite oxides showing very sharp temperature-induced metal/insulator transition. The synthesis and study of oxygen-deficient NdNiO 3− δ and SmNiO 3− δ are described in this paper. The results obtained indicate that the oxygen nonstoichiometry greatly influences transport properties of these compounds. The sharpness of metal/insulator transition strongly rises with decrease of oxygen deficiency without any noticeable change of transition temperature. The boundaries of oxygen and cation homogeneity ranges of Nd 1− x NiO 3− δ were determined for the first time. The thermogravimetric study was used to explain certain difficulties in oxidation of as-synthesized oxygen-deficient NdNiO 3− δ samples.