Superconductivity in Nanostructured Ga-Ag Eutectic Alloy

The dc and ac magnetizations were studied for the eutectic Ga-Ag alloy embedded into a porous glass with 7 nm mean pore size. The measurements were performed within a temperature range of 1.9 to 10 K which covers the superconducting transition for the nanocomposite. The onset of superconductivity at the magnetic field 10 Oe was found at about 7.1 K which is much higher than in bulk gallium. The phase diagram showed a positive curvature at low magnetic fields. The activation energy of vortex mobility was calculated at different magnetic fields using the ac data.     Keywords: Ga-Ag eutectic alloy, superconductivity, nanoconfinemen

THE EFFECT OF HYPOXIC BRAIN DAMAGE ON THE SURVIVAL OF PREMATURE INFANTS

The central nervous system injuries are a common neonatal pathology, hypoxia being one of the main causes of cerebral dysfunction. The purpose of this study was studying the incidence of hypoxic cerebral disorders in premature infants with an extremely low body weight and a very low birth weight and revealing the risk factors that adversely affected the disease outcome. The subject of the study was preterm infants whose gestational age did not exceed 31 weeks. The main criterion for inclusion into the study was the presence of hypoxic-ischemic and hypoxic-hemorrhagic brain damage. To reveal the perinatal risk factors, the somatic health of mothers, and pregnancy and childbirth peculiarities were studied. The structure of children’s pathology and intensive care techniques were analyzed. Cerebral disorders were verified in 42 out of 176 patients (23.5 %). 2–3rd-degree intraventricular hemorrhage was diagnosed in 34 newborns (80.9 %), severe ischemia in 8 children (19.1 %). To determine the structure of the disease outcome, all children were divided into deceased and survivors. A fatal outcome was observed in 14 cases (33.3 %). The mothers of deceased children were more likely to have obstetric and concomitant extragenital pathologies. Analysis of pediatric pathology showed that the hemodynamically significant functioning arterial duct and severe asphyxia in childbirth were much more frequent in deceased children. Intensive therapy of deceased children included «hard» parameters of artificial ventilation and high doses of cardiotonic drugs. Thus the presented risk factors can be considered as predictors of an unfavorable outcome in children with this pathology

ВНУТРИГОСПИТАЛЬНАЯ ТРАНСПОРТИРОВКА ПАЦИЕНТОВ С РАЗРЫВОМ АРТЕРИАЛЬНЫХ АНЕВРИЗМ ГОЛОВНОГО МОЗГА

Goal: to evaluate cerebral hemodynamics in the patients with aneurysm rupture during their transportation within the hospital. Materials and methods. 60 patients divided into 2 groups were included into the study. Patients from group 1 were transported as it was traditionally adopted in the clinic; additional sedation and continuous administration of nimodipine were used in group 2. Results. The increase of medium blood velocity in cerebral vessels by 23.5% on the operated side was observed in group 1. Continuous administration nimodipine solution during all transport stages allows reducing the velocity increase in cerebral vessels on the operated side down to 4.5%. Conclusion. The increase of cerebral angiospasm was observed during intrahospital transportation. The need for additional sedation has been justified for the patients transported while being on the artificial pulmonary ventilation. Цель: оценить церебральную гемодинамику у пациентов с разрывом аневризм при внутрибольничной транспортировке. Материалы и методы. Проведено исследование у 60 пациентов, разделенных на две группы. Больные 1-й группы транспортированы по принятой в клинике методике, а 2-й − с применением дополнительной седации и непрерывным введением нимодипина. Результаты. Отмечено нарастание средних скоростей по церебральным сосудам на 23,5% на стороне оперативного вмешательства в 1-й группе. Применение непрерывного введения раствора нимодипина на всех этапах транспортировки позволяет снизить повышение скорости по церебральным сосудам на стороне хирургического вмешательства до 4,5%. Заключение. Выявлено повышение показателей церебрального ангиоспазма при внутригоспитальной транспортировке. Обоснована необходимость применения дополнительной седации у пациентов, транспортируемых с применением искусственной вентиляции легких.

INTRAHOSPITAL TRANSPORT OF PATIENTS WITH RUPTURE OF CEREBRAL ARTERY ANEURYSM

Goal: to evaluate cerebral hemodynamics in the patients with aneurysm rupture during their transportation within the hospital. Materials and methods. 60 patients divided into 2 groups were included into the study. Patients from group 1 were transported as it was traditionally adopted in the clinic; additional sedation and continuous administration of nimodipine were used in group 2. Results. The increase of medium blood velocity in cerebral vessels by 23.5% on the operated side was observed in group 1. Continuous administration nimodipine solution during all transport stages allows reducing the velocity increase in cerebral vessels on the operated side down to 4.5%. Conclusion. The increase of cerebral angiospasm was observed during intrahospital transportation. The need for additional sedation has been justified for the patients transported while being on the artificial pulmonary ventilation

Coexistence of magnetic states and metamagnetism in the Bi

The dichalcogenide Bi2Te3 and Bi2Se3 crystals belong to the 3D topological insulator family. Doping the crystals with magnetic ions can break the time-reversal symmetry and open an energy gap at surface Dirac points. This provides the opportunity of manipulating the surface transport and observing the anomalous quantum Hall effect. We studied magnetic properties of three single-crystalline Bi$_{2-x}$ CrxSe3 samples with $x = 0.01$ , 0.03, and 0.06 within a temperature range from 2 to 300 K. The dc magnetization revealed the coexistence of antiferromagnetic and ferromagnetic ordering and paramagnetism. Their significance depends on the chromium content. The ferromagnetic phase transition was suppressed by high enough magnetic field. The antiferromagnetic transition near 80 K did not shift visibly up to 50 kOe. The Curie-Weiss law approximation gave the effective magnetic moment $\mu_{\textit{eff}}$ close to $4.9\;{\mu_{B}}$ , which corresponds to divalent chromium ions. Metamagnetic phenomena were found for crystals with $x=0.03$ and 0.06

Multifunctional Gd2O3:Tm3+, Er3+, Nd3+ particles with luminescent and magnetic properties

Development of novel materials with advanced properties is one of the main research directions of chemistry. New substances are not only crucial for many current technological applications but also should satisfy the needs of tomorrow. Industry often requires reliable, economically effective methods that can provide high quality reproducible results. Here we propose an inexpensive synthesis method that is suitable for synthesis of many types of particles. In this work we focused on Gd2O3:Tm3+, Er3+, Nd3+ particles with luminescence and magnetic properties. Based on the analysis of morphology, structural and optical properties of particles prepared by the standard Pechini methods and its variations, we found that the method with K2CO3 as additive yields particles with smaller sizes (down to tens of nm), higher crystallinity, and up to 1.7 times increased luminescence intensity. We also demonstrate that the unique combination of the particles' characteristics, for example, the intensity ratio of the luminescent bands corresponding to different REI and the mass susceptibility, strongly depends on the composition, synthesis method, and structure. The variety of the combination of the properties makes these particles a promising candidate for safety markers applications.& nbsp

Superconductivity in Nanostructured Ga-Ag Eutectic Alloy

The dc and ac magnetizations were studied for the eutectic Ga-Ag alloy embedded into a porous glass with 7 nm mean pore size. The measurements were performed within a temperature range of 1.9 to 10 K which covers the superconducting transition for the nanocomposite. The onset of superconductivity at the magnetic field 10 Oe was found at about 7.1 K which is much higher than in bulk gallium. The phase diagram showed a positive curvature at low magnetic fields. The activation energy of vortex mobility was calculated at different magnetic fields using the ac data.     Keywords: Ga-Ag eutectic alloy, superconductivity, nanoconfinemen