398 research outputs found

    High pressure effects in fluorinated HgBa2Ca2Cu3O(8+d)

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    We have measured the pressure sensitivity of Tc in fluorinated HgBa2Ca2Cu3O(8+d) (Hg-1223) ceramic samples with different F contents, applying pressures up to 30 GPa. We obtained that Tc increases with increasing pressure, reaching different maximum values, depending on the F doping level, and decreases for a further increase of pressure. A new high Tc record (166 K +/- 1 K) was achieved by applying pressure (23 GPa) in a fluorinated Hg-1223 sample near the optimum doping level. Our results show that all our samples are at the optimal doping, and that fluorine incorporation decreases the crystallographic aa-parameter concomitantly increasing the maximum attainable Tc. This effect reveals that the compression of the aa axes is one of the keys that controls the Tc of high temperature superconductors.Comment: 4 pages, 4 figures, submitted to Phys. Rev.

    О нахождении закона движения межфазной границы в задачах, моделирующих кинетику фазовых превращений

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    An analytical method for solution of multidimensional problems of heat conductivity with phase transformations which is based on integral equation method has been developed. The method makes it possible to determine interfacial boundary motion law excluding determination of temperature field and it also permits to investigate stability of its shape. The paper reveals that the proposed method is rather efficient in the case when heat transfer takes place in one phase.Разработан аналитический метод решения многомерных задач теплопроводности с фазовыми превращениями, базирующийся на методе интегральных уравнений, позволяющий, не определяя температурное поле, определять закон движения межфазной границы, а также исследовать устойчивость ее формы. Показано, что предложенный метод является достаточно эффективным в случае, когда теплоперенос происходит в одной фазе

    Synthesis of Single Phase Hg-1223 High Tc Superconducting Films With Multistep Electrolytic Process

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    We report the multistep electrolytic process for the synthesis of high Tc single phase HgBa2Ca2Cu3O8+ (Hg-1223) superconducting films. The process includes : i) deposition of BaCaCu precursor alloy, ii) oxidation of BaCaCu films, iii) electrolytic intercalation of Hg in precursor BaCaCuO films and iv) electrochemical oxidation and annealing of Hg-intercalated BaCaCuO films to convert into Hg1Ba2Ca2Cu3O8+ (Hg-1223). Films were characterized by thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrolytic intercalation of Hg in BaCaCuO precursor is proved to be a novel alternative to high temperature-high pressure mercuration process. The films are single phase Hg-1223 with Tc = 121.5 K and Jc = 4.3 x 104 A/cm2.Comment: 17 Pages, 10 Figures. Submitted to Superconductor Science and Technolog

    Outcomes in poor responders treated with in vitro fertilization/intracytoplasmic sperm injection according to bologna criteria

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    Purpose of the study was to evaluate the effectiveness of various approaches of artificial reproductive technologies (ART) in advanced maternal age patients with poor ovarian response (POR). Materials and methods. This is retrospective cohort study of 455 patients with POR who have undergone an IVF and embryo transfer program at from June 2016 to June 2018. Researchers evaluated pregnancy rate (PR) per embryo transferand live birth rate (LBR) per embryo transferas in vitro fertilization (IVF) outcomes. The patients fulfilled Bologna criteria were divided into 5 groups: long protocol, ant-gonadotropin-releasing hormone protocol, freeze embryos transfer without preimplantation genetic diagnostic (PGS), freeze embryos transfer with PGS, natural cycle. Results. There was no statistically significant difference in the age, Anti-Müllerian hormone level and duration of infertility between the groups. Despite different protocols of ovarian stimulation, there was no statistically significant difference in pregnancy rate in fresh cycles. At the same time, cancellation of transfer was significantly higher observed in natural cycles (p <0.001). PR and LBR were statistically significant higher in freeze embryo transfer group 29% and 12.1% vs 13.3% and 5,5% respectively (p<0.001 and p = 0.040). During the transfer of the embryo unexamined by PGS and after PGS the pregnancy rate did not differ (29.4% vs 28.2%, p <0.05), but LBR was statistically significant higher after euploid embryo transfer (8.2% without PGS vs 20.5% after PGS, p = 0.028). Conclusion. The most effective approach in patients with a poor ovarian response was cycle segmentation, cryopreservation of embryos, PGS and transfer of an euploid embryo. This category of patients requires a personalized approach to the treatment of infertility. The choice of protocol in ART program must be carried out with the full voluntary and informed consent of the patient, depending on their desires and capabilities, including financial

    Chronic endometritis and infertility — in vitro fertilization outcomes: systematic review and meta-analysis

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    Background. The relevance of the problem is related to the high prevalence of chronic endometritis (CE); its role in female infertility, implantation failures during assisted reproductive technology procedures, and recurrent miscarriage; as well as the lack of a unified strategy in the diagnosis and treatment of this pathology. The present systematic review with a meta-analysis focuses on evaluating the impact of CE and its therapy on the outcome of in vitro fertilization. In addition, the effect of CE of various severity on the outcomes of assisted reproductive technologies is analyzed. Objective. To analyze the effect of CE of varying severity and its treatment on the outcomes of in vitro fertilization. Methods. Using PubMed, Medline, Scopus, Embase, ELibrary, Cochrane Central Register of Controlled Trials (CENTRAL), WHO International Clinical Trials Registry, and Russian Science Citation Index, a systematic search was conducted for articles published over the past 12 years that met the following criteria: randomized controlled trial examining the effect of CE of varying severity on fertility and ways to treat it. The following indicators were calculated: ongoing pregnancy/live birth, clinical pregnancy, and miscarriage rates. A total of 4145 patients (from ten studies) were included. A meta-analysis was performed using Stata 11.0 software (The Cochrane Collaboration, Oxford, UK). The heterogeneity was considered low at I2 &lt;30%, moderate at 30–50%, and high at &gt;50%. Results. Women with CE exhibited lower ongoing pregnancy/live birth (OR 1.97; p = 0.02) and clinical pregnancy rates (OR 2.28; p = 0.002) as compared to women without it. CE treatment increased the ongoing pregnancy/live birth (OR 5.33; p &lt; 0.0001) and clinical pregnancy rates (OR 3.64; p = 0.0001). In vitro fertilization outcomes were comparable in women treated for CE and women without CE (ongoing pregnancy/live birth rate, clinical pregnancy rate, and miscarriage rate: p = ns). Women with severe CE exhibited lower ongoing pregnancy/live birth (OR 0.43; p = 0.003) and clinical pregnancy rates (OR 0.40; p = 0.0007). Mild CE showed no significant effect on in vitro fertilization outcomes (ongoing pregnancy/ live birth rate, clinical pregnancy rate, and miscarriage rate: p = ns). Conclusion. The conducted meta-analysis showed that CE significantly reduces the ongoing pregnancy/live birth and clinical pregnancy rates in infertile women undergoing in vitro fertilization. Noteworthy is that antimicrobial therapy in such patients improves the results of assisted reproductive technologies, which are comparable to those of patients without CE. The negative impact of this pathology on the implantation capacity of the endometrium is most often observed in the severe form, while its mild form has virtually no effect on the in vitro fertilization outcome

    ПРИМЕНЕНИЕ ИНГАЛЯЦИОННЫХ АНЕСТЕТИКОВ ВО ВРЕМЯ ИСКУССТВЕННОГО КРОВООБРАЩЕНИЯ

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    Protection of myocardium from ischemic and reperfusion lesions continues to be an important issue in the modern cardiac surgery. Russian and foreign publications contain a significant number of data about the protective impact of pre- and post-conditioning with inhalation anesthetics (sevoflurane, isoflurane, and desflurane) on the myocardium. The article highlights that this protective action is maximum when these drugs are used during the whole operation and it means during cardiopulmonary bypass as well. Therefore, currently, the listed above inhalation anesthetics are used fairly frequent during cardiopulmonary bypass. However, the technology of inhalation anesthesia during perfusion has a number of specific features: changes in the pharmacokinetics of drugs (which provides impact on the dosing of anesthetics), design of oxygenator, which plays a certain role when the anesthetics are supplied to the blood, monitoring during inhalation anesthesia, technical assistance for this technology and important safety issues. This review describes the above-mentioned aspects.В современной кардиохирургии не теряет актуальности проблема защиты миокарда от ишемического и реперфузионного повреждений. В отечественной и зарубежной литературе существует большое количество данных о протективном влиянии на миокард анестетического пре- и посткондиционирования ингаляционными анестетиками (севофлураном, изофлураном и десфлураном). В работе группы авторов подчеркивается, что в наибольшей степени данное влияние реализуется при использовании этих препаратов в течение всей операции, а значит, и во время искусственного кровообращения (ИК). Поэтому в настоящее время перечисленные ингаляционные анестетики в ходе ИК применяют достаточно часто. Одновременно с этим сама технология проведения ингаляционной анестезии в течение перфузии имеет ряд особенностей: изменения в фармакокинетике препаратов (что влияет на процесс дозирования анестетиков), строение оксигенатора, играющее роль в поступлении анестетика в кровь, вопросы мониторинга во время ингаляционной анестезии, техническое обеспечение самой методики и важные вопросы безопасности ее проведения. Настоящий обзор литературы освещает именно эти моменты

    Circulating prolactin levels and risk of epithelial ovarian cancer

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    Purpose: Indirect evidence from experimental and epidemiological studies suggests that prolactin may be involved in ovarian cancer development. However, the relationship between circulating prolactin levels and risk of ovarian cancer is unknown. Methods: We conducted a nested case-control study of 230 cases and 432 individually matched controls within three prospective cohorts to evaluate whether pre-diagnostic circulating prolactin is associated with subsequent risk of ovarian cancer. We also assessed whether lifestyle and reproductive factors are associated with circulating prolactin among controls. Results: Prolactin levels were significantly lower among post- versus pre-menopausal women, parous versus nulliparous women, and past versus never users of oral contraceptives in our cross-sectional analysis of controls. In our nested case-control study, we observed a non-significant positive association between circulating prolactin and ovarian cancer risk (ORQ4vsQ1 1.56, 95 % CI 0.94, 2.63, p trend 0.15). Our findings were similar in multivariate-adjusted models and in the subgroup of women who donated blood 655 years prior to diagnosis. We observed a significant positive association between prolactin and risk for the subgroup of women with BMI 6525 kg/m2 (ORQ4vsQ1 3.10, 95 % CI 1.39, 6.90), but not for women with BMI &lt;25 kg/m2 (OR Q4vsQ1 0.81, 95 % CI 0.40, 1.64). Conclusions: Our findings suggest that prolactin may be associated with increased risk of ovarian cancer, particularly in overweight/obese women. Factors associated with reduced risk of ovarian cancer, such as parity and use of oral contraceptives, were associated with lower prolactin levels, which suggests that modulation of prolactin may be a mechanism underlying their association with risk

    Evaluation of midkine and anterior gradient 2 in a multimarker panel for the detection of ovarian cancer

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    The aims of this study were: to characterise and compare plasma concentrations of midkine (MDK) in normal healthy women with concentrations observed in women with ovarian cancer; and to establish and compare the performance of MDK with that of anterior gradient 2 protein (AGR2) and CA125 in the development of multi-analyte classification algorithms for ovarian cancer. Median plasma concentrations of immunoreactive MDK, AGR2 and CA125 were significantly greater in the case cohort (909 pg/ml, 765 pg/ml and 502 U/ml, respectively n = 46) than in the control cohort (383 pg/ml, 188 pg/ml and 13 U/ml, respectively n = 61) (p < 0.001). The area under the receiver operator characteristic curve (AUC) for MDK and AGR2 was not significantly different (0.734 ± 0.046 and 0.784 ± 0.049, respectively, mean ± SE) but were both significantly less than the AUC for CA125 (0.934 ± 0.030, p < 0.003). When subjected to stochastic gradient boosted logistic regression modelling, the AUC of the multi-analyte panel (MDK, AGR2 and CA125, 0.988 ± 0.010) was significantly greater than that of CA125 alone (0.934 ± 0.030, p = 0.035). The sensitivity and specificity of the multi-analyte algorithm were 95.2 and 97.7%, respectively. Within the study cohort, CA125 displayed a sensitivity and specificity of 87.0 and 94.6%, respectively. The data obtained in this study confirm that both MDK and AGR2 individually display utility as biomarkers for ovarian cancer and that in a multi-analyte panel significantly improve the diagnostic utility of CA125 in symptomatic women
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