(Na, Zr) and (Ca, Zr) Phosphate-Molybdates and Phosphate-Tungstates: II-Radiation Test and Hydrolytic Stability.

This paper introduces the results of hydrolytic stability tests and radiation resistance tests of phosphate molybdates and phosphate tungstates Na1-xZr2(PO4)3-x(XO4)x, X = Mo, W (0 ≤ x ≤ 0.5). The ceramics characterized by relatively high density (more than 97.5%) were produced by spark plasma sintering (SPS) of submicron powders obtained by sol-gel synthesis. The study focused on hydrolytic resistance of the ceramics in static mode at room temperature. After 28 days of testing in distilled water, the normalized leaching rate was determined. It was found that the ceramics demonstrated high hydrolytic resistance in static mode: the normalized leaching rates for Mo- and W-containing ceramics were 31·10-6 and 3.36·10-6 g·cm-2·day-1, respectively. The ceramics demonstrated high resistance to irradiation with 167 MeV Xe+26 multiple-charged ions at fluences ranging from 1·1012 to 6·1013 cm-2. The Mo-containing Na0.5Zr2(PO4)2.5(XO4)0.5 ceramics were shown to have higher radiation resistance than phosphate tungstates. Radiation was shown to trigger an increase in leaching rates for W and Mo in the crystal structure of NZP ceramics.

(Na, Zr) and (Ca, Zr) Phosphate-Molybdates and Phosphate-Tungstates: I-Synthesis, Sintering and Characterization.

Submicron-grade powders of Na1-xZr2(PO4)3-x(XO4)x compounds (hereafter referred to as NZP) and Ca1-xZr2(PO4)3-x(XO4)x compounds (hereafter, CZP), X = Mo, W (0 ≤ x ≤ 0.5) were obtained by sol-gel synthesis. The compounds obtained were studied by X-ray diffraction phase analysis and electron microscopy. An increase in the W or Mo contents was shown to result in an increase in the unit cell volume of the NZP and CZP crystal lattices and in a decrease in the coherent scattering region sizes. Thermal expansion behavior at high temperatures of synthesized NZP and CZP compounds has been investigated. The dependencies of the parameters a and c on the heating temperature, as well as the temperature dependence of the crystal lattice unit cell volume V in the range from the room temperature up to 800 °C, were obtained. The dependencies of the average thermal expansion coefficient (αav) and of the volume coefficient (ß) on the W and Mo contents in the compositions of NZP and CZP compounds were studied. Ceramics Na1-xZr2(PO4)3-x(XO4)x with relatively high density (more than 97.5%) were produced by spark plasma sintering (SPS). The increase in the W or Mo contents in the ceramics leads to an increase in the relative density of NZP and to a decrease of the optimum sintering temperature. The mean grain size in the NZP ceramics decreases with increasing W or Mo contents. The study of strength characteristics has revealed that the hardness of the NZP ceramics is greater than 5 GPa, and that the minimum fracture toughness factor was 1 MPa·m1/2.

Discrete dislocation simulation of the ultrasonic relaxation of non-equilibrium grain boundaries in a deformed polycrystal.

For the first time, the relaxation of disordered dislocation arrays in a model 3 × 3 columnar polycrystal under ultrasonic action is studied using the discrete dislocation approach. All grains contain three non-parallel slip systems located at an angle of 60° to each other. The non-equilibrium state of the grain boundaries is modeled using two finite edge dislocation walls with Burgers vector of opposite signs, which are equivalent to a wedge junction disclination quadrupole. It is shown that ultrasonic treatment causes a significant rearrangement of the lattice dislocations and their gliding towards the grain boundaries. It results in a decrease in the internal stress fields associated with the presence of non-equilibrium grain boundaries and relaxation of dislocation structure. The model predicts an existence of optimal amplitude, at which the maximum relaxing effect can be achieved. Dependence of the relaxation of dislocation structure on the grain size is also investigated.

The antioxidant 2,6-di-tert-butylphenol moiety attenuates the pro-oxidant properties of the auranofin analogue.

Metal-based drugs are gaining momentum as a rapidly developing area of medicinal inorganic chemistry. Among gold pharmaceuticals, auranofin is a well known antirheumatic drug. The efficacy of gold-organic complexes largely depends on their pro-oxidant properties since auranofin targets the redox enzyme thioredoxin reductase (TrxR). However, an uncontrollable oxygen burst may be harmful for healthy cells; therefore, the search for chemical modifications to attenuate oxidation-related general toxicity of gold containing anti-inflammatory drugs is justified. In this study, we demonstrate that the incorporation of a specific antioxidant phenol fragment can counterbalance the pro-oxidative potential of the Au containing complex molecule. The electrochemical studies of AuPPh3SR (1, R= 3,5-di-tert-butyl-4-hydroxyphenyl) and its precursors AuPPh3Cl (2) and RSH (3) showed that complex 1 and phenol 3 efficiently scavenged the radicals (as detected by cyclic voltammetry) whereas 2 had no effect. Compound 1 inhibited TrxR in vitro with IC50 0.57 ± 0.15 µM, a value one order of magnitude bigger than the potency reported for auranofin. Compound 1 (5 mg kg-1 daily gavage for 14 days) caused a decrease in ex vivo spontaneous and ascorbate-induced lipid peroxidation in the homogenates of rat lung, heart muscle, spleen, liver, kidneys, testicles and brain as assessed by the thiobarbituric acid reactive substances. Importantly, in animals fed with 1, no discernible general toxicity was registered suggesting that this compound is well tolerated. Our results provide evidence for an efficient synthetic route to obtain gold containing anti-inflammatory drug candidates with balanced pro/anti-oxidative properties.

Microstructure changes in ultrafine-grained nickel processed by high pressure torsion under ultrasonic treatment.

Commercially pure nickel was processed by high pressure torsion (HPT) and subjected to ultrasonic treatment (UST) with different amplitudes of compression-tension stresses in the zone of stress antinode of a standing wave. It was found that microstructure parameters such as the dislocation density, low- and high-angle grain boundary fractions, microhardness, and the stored excess energy as well, non-monotonically depend on the ultrasound amplitude. A structure relaxation leading to a reduction of internal stresses and stored energy and increase of the fraction of high-angle boundaries was observed at some intermediate amplitudes of the oscillating stress. The maximum relaxation effect was observed in the samples after UST with the amplitude of 60MPa. Possible mechanisms of the influence of ultrasound on the microstructure of deformed materials are discussed.

Determination of the conformal-field-theory central charge by the Wang-Landau algorithm.

We present a simple method to estimate the central charge of the conformal field theory corresponding to a critical point of a two-dimensional lattice model from Monte Carlo simulations. The main idea is to use the Wang-Landau flat-histogram algorithm, which allows us to obtain the free energy of a lattice model on a torus as a function of torus radii. The central charge is calculated with good precision from a free-energy scaling at the critical point. We apply the method to the Ising, tricritical Ising (Blume-Capel), Potts, and site-diluted Ising models, and we also discuss an estimation of the conformal weights.

Drift of dislocation tripoles under ultrasound influence.

Numerical simulations of dynamics of different stable dislocation tripoles under influence of monochromatic standing sound wave were performed. The basic conditions necessary for the drift and mutual rearrangements between dislocation structures were investigated. The dependence of the drift velocity of the dislocation tripoles as a function of the frequency and amplitude of the external influence was obtained. The results of the work can be useful in analysis of motion and self-organization of dislocation structure under ultrasound influence.

[Possibilities of systemic radiotherapy with high-purity 89Sr chloride in the treatment of bone metastases].

OBJECTIVE: To study the efficiency of treatment via single administration of high-purity 89Sr chloride in the standard activity of 150 MBq for pain syndrome in patients with multiple bone metastases. SUBJECTS AND METHODS: The authors carried out clinical trials of high-purity 89Sr chloride used to treat 30 patients with multiple bone metastases from cancers at various sites. The results of treatment were analyzed in 30 patients with multiple bone metastases, who had received systemic radiation therapy with high-purity 89Sr chloride in the standard activity of 150 MBq. These were assessed using some indicators: the intensity of pain syndrome and the blood concentrations of hemoglobin, leukocytes, and platelets. RESULTS: There was evidence for the use of high-purity 89Sr chloride in the therapy of patients with cancer at various sites with multiple bone metastases. The major indicators (pain syndrome, the blood concentrations of hemoglobin, leukocytes, and platelets) were compared before and after the treatment. These were also compared with those obtained with the use of usual 89Sr chloride. CONCLUSION: The therapeutic action of high-purity 89Sr chloride is comparable with that of 89Sr chloride in the standard activity; moreover, the analgesic effect of high-purity 89Sr chloride is being significantly higher. It has less significant myelotoxic activity than usual 89Sr chloride. High-purity 89Sr chloride is an effective radiopharmaceutical agent and may be used for systemic radiotherapy in patients with multiple bone metastatic lesion.

[Strontium chloride (89Sr-chloride) fractional injection method for bone metastases treatment].

The study was designed to compare the effectivnes of 89Sr-chlorid injections by 50 Mbk fractions with standard 150 Mbk injection in patients with bone metastases. Fifty patients with bone metastases were included in the study, 25 of them received 89Sr-chloride by fractional and 25 (control group) by single injection. The pain intensity, white blood cells and thrombocytes concentration values were evaluated in both groups before and after treatment. The study proved the possibility of using systemic 89Sr-chloride fractional radiotherapy in patients with bone metastases and concurrent stage 2-3 myelosupression. The method of fractial 89Sr-chloride injection is effective in symptomatic treatment of patients with bone metastases.

[Systemic radiotherapy options in the treatment of metastatic skeletal involvement].

OBJECTIVE: To evaluate the efficiency of treatment using various systemic radiotherapies for metastatic skeletal involvement in patients with breast or prostate cancer. MATERIAL AND METHODS: The case histories of 350 patients treated at the Department of Radiation Medicine in 2006 to 2010 for multiple metastatic skeletal involvement in cancers at various sites were analyzed. The efficiency of treatment for pain syndrome and the magnitude of a myelosuppressive effect were estimated in the use of various systemic radiotherapies. For this, the authors compared: 1) two patient groups treated by 89Sr chloride monotherapy in the standard activity of 150 MBq or by that in combination with teleradiotherapy (TRT); 2) two patient groups treated by the monotherapy in the standard activity of 150 MBq or by 89Sr chloride fractional injection. RESULTS: The efficiency of treatment using various systemic radiotherapies was estimated. That was comparatively evaluated in the patient groups having various treatments. Algorithms of indications were elaborated to choose a systemic radiotherapy option depending on the clinical situation. An 89Sr chloride injection procedure was developed for patients with significant myelosuppression. CONCLUSION: 1. Various systemic radiotherapies as second-line therapy may be used to treat metastatic skeletal involvement in patients with cancer at various sites. 2. The most pronounced analgesic effect was found when 89Sr chloride in the standard activity of 150 MBq had been injected in combination with TRT (a 36% reduction in the intensity of pain syndrome); a less pronounced effect was produced by 89Sr chloride monotherapy (27%). The lowest analgesic effect was observed when 89Sr chloride had been fractionally injected (14%). 3. The levels of white blood cells and platelets were decreased in all the groups. 4. 89Sr chloride fractional injection is the method of choice when its single administration is impossible in patients with evident leukocyto- and thrombocytopenia.

[The analysis of 49A/G CTLA4 gene polymorphism association with development of allergic rhinitis].

Polymorphism of 49A/G gene CTLA4 in 44 patients with allergic rhinitis and 70 conditioned healthy donors of Uzbek population has been analyzed. The "unfavourable allele" rate in general studied groups and control groups did not practically differ and was 73,3 and 72,9% correspondingly. The analysis of distribution of polymorphism 49A/G gene CTLA4 among the patients of the groups with allergic rhinitis depended on currency (seasonal form) and gender, while in the control groups statistical significant differences were not revealed. However, in patients with annually forms of allergic rhinitis the rate of functional "unfavourable allele" 49A/G gene CTLA4 increased in 1,3 times in comparison with the group with seasonal form and slightly in the control group.

[Results of testing of MINISKAN mobile gamma-ray camera and specific features of its design].

The main results of engineering, biomedical, and clinical testing of MINISKAN mobile gamma-ray camera are presented. Specific features of the camera hardware and software, as well as the main technical specifications, are described. The gamma-ray camera implements a new technology based on reconstructive tomography, aperture encoding, and digital processing of signals.

Competing relaxation mechanisms in a disclinated nanowire: temperature and size effects.

This Letter reports a molecular dynamics study of the temperature and size dependence of disclination relaxation in a bicrystalline titanium nanowire. The simulations show that an unstable disclination may relax via crack nucleation and/or structural transformation. The critical disclination strength to nucleate a crack decreases with the nanowire diameter at 0 K, but an inverse relation may exist at higher temperatures. Similar relaxation mechanisms are operative in other hcp materials. The results suggest that grain boundaries in nanostructured materials can be disordered through disclinations which relax via amorphization.

[Reconstruction of the anus in marginal necrosis of the lowered intestine after abdominal-anal resection]. / Rekonstruktsiia zadnego prokhoda pri kraevom nekroze nizvedennoi kishki posle briushno-anal'noi rezektsii.

The experience with treatment of a most frequent complication after abdomino-anal resection with bringing down the intestine--marginal necrosis of a xenotransplant--is summarized. The expediency of individual approach to the choice of treatment is noted. Active therapeutical tactics is suggested.