Профілактика специфічних ускладнень ендовенозної лазерної коагуляції

Мета. Розробити методику профілактики специфічних ускладнень ендовенозної лазерної коагуляції. Матеріали і методи. Запропоновано спосіб профілактики розвитку специфічних ускладнень ендовенозної лазерної коагуляції шляхом активного видалення продуктів коагуляції з просвіту вени. Проведено спостереження за двома групами хворих, яким виконували лазерне втручання класичним методом (1-ша група) та з використанням розробленої методики (2-га група). Результати. Запропоновані спосіб і пристрій для вакуумної евакуації продуктів коагуляції із зони операції унеможливлюють потрапляння їх у венозну систему і запобігають розвитку ранніх специфічних післяопераційних ускладнень («металевого» присмаку в роті, головного болю, запаморочення, загального нездужання, «важкості» дихання), що покращує перебіг післяопераційного періоду. Висновки. Вакуумна евакуація продуктів коагуляції з просвіту вени запобігає їх потраплянню у загальну венозну систему, мінімізує частоту розвитку специфічних ускладнень і покращує перебіг раннього післяопераційного періоду. Використання методики профілактики ускладнень ендовенозної лазерної коагуляції в лікуванні варикозної хвороби і пристрою для його реалізації не ускладнює виконання операції і не збільшує її вартість

Effect of Cr spacer on structural and magnetic properties of Fe/Gd multilayers

In this work we analyse the role of a thin Cr spacer between Fe and Gd layers on structure and magnetic properties of a [Fe(35A)/Cr(tCr)/Gd(50A)/Cr(tCr)]x12 superlattice. Samples without the Cr spacer (tCr=0) and with a thin tCr=4A are investigated using X-ray diffraction, polarized neutron and resonance X-ray magnetic reflectometry, SQUID magnetometery, magneto-optical Kerr effect and ferromagnetic resonance techniques. Magnetic properties are studied experimentally in a wide temperature range 4-300K and analysed theoretically using numerical simulation on the basis of the mean-field model. We show that a reasonable agreement with the experimental data can be obtained considering temperature dependence of the effective field parameter in gadolinium layers. The analysis of the experimental data shows that besides a strong reduction of the antiferromagnetic coupling between Fe and Gd, the introduction of Cr spacers into Fe/Gd superlattice leads to modification of both structural and magnetic characteristics of the ferromagnetic layers

Тенденции развития комплексных транспортных схем городов

The article discusses the process of planning the work of urban transport operations in the form of an integrated transport scheme (ITS), which is the transport part of the master plan for development of a city, and studies organization of urban transport. The objective of the article is to formulate the main directions of developments in the field of transport planning based on modern domestic and foreign experience and knowledge, and on retrospective analysis of changes in the field of urban transport planning.The methodology is presented for the conditions prevailing in the Russian Federation, the peculiarity of which comprise a relatively late (compared to European countries and the USA), but rapidly developing motorization of the country, a change in qualifications of specialists working in the field of urban transport planning, a certain loss of experience and skills in development of ITS in recent years.The suggested conclusions represent a brief description of the concept of a common toolkit, a scheme and the most promising methods for developing approaches to development of integrated transport schemes and require further in-depth research in each specific segment.В статье рассматривается процесс планирования работы городского транспорта в форме комплексной транспортной схемы (КТС), являющейся транспортной частью генерального плана развития города и рассматривающей вопросы организации городского транспорта. Цель статьи – сформулировать основные направления разработок в сфере транспортного планирования на основе современного отечественного и зарубежного опыта и знаний, в том числе с использованием ретроспективного анализа изменений в сфере планирования городского транспорта.Анализ представлен для условий Российской Федерации, особенностями которых являются относительно поздняя (по сравнению со странами Европы и США), но быстро протекающая автомобилизация страны, изменение квалификационного состава специалистов, работающих в сфере планирования городского транспорта, определённая потеря опыта и умения разработки КТС за последние годы.Предложенные выводы представляют собой краткое описание концепта общего инструментария, схем и наиболее перспективных методов разработки подходов к развитию комплексных транспортных схем и требуют дальнейших углублённых исследований по каждому направлению

Highly-controlled grafting of mono and dicationic 4,4′-bipyridine derivatives on SBA-15 for potential application as adsorbent of CuCl2 from ethanol solution

AbstractThis work describes a highly controlled post-grafting of mono and dicationic 4,4′-bipyridine alkoxysilane derivatives (Bipy+ and Bipy2+) onto the surface of an ordered mesoporous silica, SBA-15. The materials obtained are designated as SBA-15/Bipy+Cl− and SBA-15/Bipy2+Cl2-, both possessing chloride as counter ion. The regular arrangement of uniform pores of this inorganic matrix is likely to ensure good accessibility to the active centers (electron acceptors) attached to the surface. The materials are excellent adsorbents due to the ability of the functional groups to retain copper chlorides on their surfaces as anionic complexes (CuCl2+nn-) in ethanol. From the adsorption, results it was possible to probe the functional surface monolayer of the materials, which present a highly homogenous distribution of functional groups inside the ordered SBA-15 channels, with an exchange efficiency of 93% for SBA-15/Bipy+Cl− and 94% for SBA-15/Bipy2+Cl2-. Both adsorbent materials are potentially useful in the pre-concentration and further analysis of Cu(II) present in trace amounts in ethanol, extensively used as an automotive fuel in Brazil

The ion exchange properties and equilibrium constants of Li+, Na+ and K+ on zirconium phosphate highly dispersed on a cellulose acetate fibers surface

Highly dispersed zirconium phosphate was prepared by reacting celullose acetate/ZrO2 (ZrO2 = 11 wt%, 1.0 mmol g-1 of zirconium atom per gram of the material) with phosphoric acid. High power decoupling magic angle spinning (HPDEC-MAS) 31P NMR and X-ray photoelectron spectroscopy data indicated that HPO4(2-) is the species present on the membrane surface. The specific concentration of acidic centers, determined by ammonia gas adsorption, is 0.60 mmol g-1. The ion exchange capacities for Li+, Na+ and K+ ions were determined from ion exchange isotherms at 298 K and showed the following values (in mmol g-1): Li+= 0.05, Na+= 0.38 and K+= 0.57. Due to the strong cooperative effect, the H+/Na+ and H+/K+ ion exchange is of non ideal nature. These ion exchange equilibria were treated with the use of models of fixed tridentate centers, which consider the surface of the sorbent as polyfunctional sorption centers. Both the observed ion exchange capacities with respect to the alkaline metal ions and the equilibrium constants are discussed by taking into consideration the sequence of the ionic hydration radii for Li+, Na+ and K+. The matrix affinity for the ions decreases with increasing the cations hydration radii from K+ to Li+. The high values of the separation factors S Na+/Li+ and S K+/Li+ (up to several hundreds) support the application of this material for the quantitative separation of Na+ and K+ from Li+ from a mixture containing these three ions.Fosfato de zircônio altamente disperso foi preparado reagindo acetato de celulose/ZrO2 (ZrO2 = 11 wt%, 1,0 mmol g-1 de átomo de zircônio por grama de material) com ácido fosfórico. Os dados de RMN 31P (HPDEC-MAS) com rotação de ângulo mágico desacoplado e Espectroscopia de Fotoelétron de raios-X indicam que a espécie HPO4(2-) está presente na superfície da membrana. A concentração específica de centros ácidos, determinada pela adsorção de gás amônia, foi de 0,60 mmol g-1. As capacidades de troca-iônica dos íons Li+, Na+ e K+ foram determinadas das isotermas de troca-iônica à 298 K e mostraram os seguintes valores ( em mmol g-1): Li+ = 0,05, Na+ = 0,38 e K+ = 0,57. Devido ao forte efeito cooperativo a troca-iônica de H+/Na+ e H+/K+ apresentou natureza não ideal. Esse equilíbrio de troca-iônica foi tratado com o uso de modelos de centros bi ou tridentados que considera a superfície do sorvente como centros de sorção polifuncionais. Tanto as capacidades de troca-iônica observadas com os respectivos íons metálicos alcalinos quanto as constantes de equilíbrio foram discutidas considerando a seqüência dos raios de hidratação iônicos para Li+, Na+ e K+. As afinidades para os íons diminuem com o aumento do raio de hidratação dos cátions, por ex. Li+< Na+ < K+ . Os altos valores dos fatores de separação de S Na+/Li+ e S K+/Li+ permitem aplicar este material para a separação quantitativa de Na+ e K+ de Li+ de uma mistura contendo esses três íons.5057Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Cyclic voltammetry of tris(2,2-bipyridine)zinc(II) diperchlorate detected by electron spin resonance

Electrochemical transformations of the tris(2,2-bipyridine) complex of zinc(II) perchlor- ate were studied by cyclic voltammetry detected by electron spin resonance (DESR CV), which made it possible to indentify the intermediates formed and to monitor the unpaired electron localization in them. © 2013 Springer Science+Business Media, Inc

Adsorption of metal ions on novel 3-n-propyl (methylpyridinium) silsesquioxane chloride polymers surface: study of heterogeneous equilibrium at the solid-solution interface

Polymers Si3Py+Cl- (A) and Si4Py+Cl- (B), 3-n-propyl (3-methylpyridinium) silsesquioxane and 3-n-propyl(4-methylpyridinium) silsesquioxane chlorides, respectively, were prepared by the sol-gel processing method. The ion exchange capacities (mmol g-1) were 0.90 and 0.81 for (A) and (B) respectively. Considering the reaction nSiPy+Cl-(s) + M2+(sln) + 2Cl-(sln) <IMG SRC="../img/a18setas.jpg" WIDTH=54 HEIGHT=15>(SiPy+)nMCl2+n n-(s), the values of the stepwise equilibrium constants obtained were: (A) CuII: logK(2)¹= 4.14(0.03), logK(2)²= 2.91(0.04); ZnII, logK(2)¹= 3.3(0.3), logK(2)²= 4.9(0.3); (B) CuII:logK(2)¹= 3.82(0.03), logK(2)²= 3.00(0.04); ZnII, logK(2)¹= 3.93(0.03), logK(2)²= 3.55(0.08), being K(2)¹ and K(2)² the equilibrium constants for adsorption of the species MCl4(2-) and MCl3-, respectively. For adsorption of ZnII on Si3Py+Cl-, K(2)² > K(2)¹, indicating positive cooperativity, i.e., the adsorption of MCl4(2-)enhances the adsorption of MCl3- species on the adsorbent surface. For the other cations, K(2)¹ > K(2)², indicating that adsorption of MCl4(2-)depresses the adsorption of MCl3-species, indicating negative cooperativity. <IMG SRC="../img/a18setas.jpg" WIDTH=54 HEIGHT=15

Ant-aphid relations in Costa Rica, Central America (Hymenoptera: Formicidae; Hemiptera: Aphididae)

We present the first catalogue of ant-aphid associations (Hymenoptera: Formicidae / Hemiptera: Aphididae) of Costa Rica. 29 species of ants and 18 species of aphids establish 48 relationships. Those interactions seem not to be rare in Costa Rica