Creating carbon nanotubes microenvironment in surfactant water solutions

© 2017 Trans Tech Publications, Switzerland. The infrared absorption spectra of aqueous dispersions of carbon nanotubes in the presence of surfactants and alkali metal salts in the frequency range from 1000 cm-1 to 3000 cm-1 have been studied. The possibility of controlling the characteristics of local environment of carbon nanotubes by varying external electrolyte and modulation the surfactant micelle structure has been shown

The use of endovascular thrombectomy among the patients with acute ischemic stroke caused by the occlusion of large cerebral vessels

The effectiveness and complications of endovascular thrombectomy were analyzed. The obtained results show the reduction in mortality and disability among the patients after endovascular treatmen

Mathematical Anxiety and mathematical learning: Multidimensional approach.

Research suggests that mathematical anxiety is a complex phenomenon related to mathematical achievement, developmental dyscalculia, strategies of numerical information processing, and negative emotional states. The goal of this currently on-going large-scale study is to implement a mixed method approach towards assessment of mathematical anxiety across the school grades. The methods include: a picture-based assessment; a questionnaire measuring attitudes towards mathematics; and a computerized test-battery measuring mathematics related cognitive processes. This mixed method approach addresses mathematical anxiety as a multidimensional, multi-faceted and dynamic manifestation of individual differences in a specific educational context. The research also allows exploring interrelations between non-cognitive and cognitive processes involved in mathematical anxiety. Here we present the results of the first wave of the investigation, involving data from 3 different age groups, assessed in several schools in Russia and the UK. The results suggest the importance of accounting for educational contexts in measuring and treating mathematical anxiety

Ytterbium and Europium Complexes of Redox-Active Ligands: Searching for Redox Isomerism

© 2017 American Chemical Society. The reaction of (dpp-Bian)Eu II (dme) 2 (3) (dpp-Bian is dianion of 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene; dme is 1,2-dimethoxyethane) with 2,2′-bipyridine (bipy) in toluene proceeds with replacement of the coordinated solvent molecules with neutral bipy ligands and affords europium(II) complex (dpp-Bian)Eu II (bipy) 2 (9). In contrast the reaction of related ytterbium complex (dpp-Bian)Yb II (dme) 2 (4) with bipy in dme proceeds with the electron transfer from the metal to bipy and results in (dpp-Bian)Yb III (bipy)(bipy - ). (10) - ytterbium(III) derivative containing both neutral and radical-anionic bipy ligands. Noteworthy, in both cases dianionic dpp-Bian ligands retain its reduction state. The ligand-centered redox-process occurs when complex 3 reacts with N,N′-bis[2,4,6-trimethylphenyl]-1,4-diaza-1,3-butadiene (mes-dad). The reaction product (dpp-Bian)Eu II (mes-dad)(dme) (11) consists of two different redox-active ligands both in the radical-anionic state. The reduction of 3,6-di-tert-butyl-4-(3,6-di-tert-butyl-2-ethoxyphenoxy)-2-ethoxycyclohexa-2,5-dienone (the dimer of 2-ethoxy-3,6-di-tert-butylphenoxy radical) with (dpp-Bian)Eu II (dme) 2 (3) caused oxidation of the dpp-Bian ligand to radical-anion to afford (dpp-Bian)(ArO)Eu II (dme) (ArO = OC 6 H 2 -3,6-tBu 2 -2-OEt) (12). The molecular structures of complexes 9-12 have been established by the single crystal X-ray analysis. The magnetic behavior of newly prepared compounds has been investigated by the SQUID technique in the range 2-310 K. The isotropic exchange model has been adopted to describe quantitatively the magnetic properties of the exchange-coupled europium(II) complexes (11 and 12). The best-fit isotropic exchange parameters are in good agreement with their density functional theory-computed counterparts

Study of hepatoprotective effects of xymedon

Xymedon (1-(β-oxyethyl)-4,6-dimethyl-1,2-dihydro-2-oxopyrimidine), a regeneratory and wound-healing drug, exhibited hepatoprotective activity in laboratory animals with experimental toxic hepatitis. Oral drug reduced the severity of toxic involvement of the liver induced by CCl4 and reduced animal mortality. Xymedon promoted recovery of the blood biochemical parameters characterizing the liver status. © 2013 Springer Science+Business Media New York

Structure and properties of aqueous dispersions of sodium dodecyl sulfate with carbon nanotubes

© 2016, Springer Science+Business Media New York.The dispersing action of the surfactant (sodium dodecyl sulfate, SDS) on the carbon nanotubes (CNT) in aqueous medium has been studied. Electron microscopy, molecular docking, NMR and IR spectroscopies were applied to determine the physical-chemical properties of CNT dispersions in SDS—water solutions. It was established that micellar adsorption of the surfactant on the surface of carbon material and solubilization of SDS in aqueous medium contribute to improving CNT dispersing in water solutions. It was shown that the non-polar hydrocarbon radicals of a single surfactant molecule form the highest possible number of contacts with the graphene surface. Upon increase of the SDS in solution these radicals form micelles connected with the surface of the nanotubes. At the sufficiently high SDS concentration the nanotube surface becomes covered with an adsorbed layer of surfactant micelles. Water molecules and sodium cations are concentrated in spaces between micelles. The observed pattern of micellar adsorption is somewhat similar to a loose bilayer of surfactant molecules

Combination delivery of two oxime-loaded lipid nanoparticles: Time-dependent additive action for prolonged rat brain protection

© 2018 Elsevier B.V. A novel approach for brain protection against poisoning by organophosphorus agents is developed based on the combination treatment of dual delivery of two oximes. Pralidoxime chloride (2-PAM) and a novel reactivator, 6-(5-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)pentyl)-3-hydroxy picolinaldehyde oxime (3-HPA), have been loaded in solid-lipid nanoparticles (SLNs) to offer distinct release profile and systemic half-life for both oximes. To increase the therapeutic time window of both oximes, SLNs with two different compartments were designed to load each respective drug. Oxime-loaded SLNs of hydrodynamic diameter between 100 and 160 nm and negative zeta potential (−30 to −25 mV) were stable for a period of 10 months at 4 °C. SLNs displayed longer circulation time in the bloodstream compared to free 3-HPA and free 2-PAM. Oxime-loaded SLNs were suitable for intravenous (iv) administration. Paraoxon-poisoned rats (0.8 × LD50) were treated with 3-HPA-loaded SLNs and 2-PAM+3-HPA-loaded SLNs at the dose of 3-HPA and 2-PAM of 5 mg/kg. Brain AChE reactivation up to 30% was slowly achieved in 5 h after administration of 3-HPA-SLNs. For combination therapy with two oximes, a time-dependent additivity and increased reactivation up to 35% were observed

PNL in the treatment of staghorn nephrolithiasis

Staghorn nephrolithiasis most severe course of urolithiasis. A retrospective analysis of a group of patients with staghorn nephrolithiasis (n = 50), operated by various methods, followed by determination of the optimal method of surgery. Efficacy was evaluated by the presence of residual stones, the presence of postoperative complications. All patients were divided into 4 groups according to the stage of staghorn nephrolithiasis. In 20% of identified staghorn nephrolithiasis stage 1,40% - the second, at 8% - third, 20% - fourth. 60% was performed percutaneous nephrolitholapaxy (nephrolithotripsy), 14% - pyelolithotomy, 6% - nephrolithotomy, 4% extracorporeal shock wave lithotripsy was performed. Nephrectomies were performed in 12% of cases. The effectiveness of percutaneous nephrolithotripsy comparable to open surgery, and the number of postoperative complications is minimal, less than the time of hospital treatment and postoperative rehabilitation.Коралловидный нефролитиаз наиболее тяжелое течение мочекаменной болезни. Проведен анализ группы больных с корраловидным нефропитиазом (КН) (п=50), оперированных различными методиками с последующим определением оптимального метода хирургического вмешательства. Эффективность оценивалась по наличию резидуальных камней, наличию послеоперационных осложнений. Все пациенты были разделены на 4 группы по стадии КН. В 20% выявлен КН 1 стадии, у 40 % - второй, в 8% - третей и 20% - четвертой. 60% была выполнена чрескожная нефролитолапаксия (нефролитотрипсия), 14 % - пиелолитотомия, 6 % - нефролитотомия и 4% была проведена дистанционная литотрипсия. Органуносящие операции выполнялись в 12 % случаев. Эффективность чрескожной нефролитотрипсии сопоставима с открытым оперативным вмешательством, а количество послеоперационных осложнений минимально, меньше сроки стационарного лечения и послеоперационной реабилитации