Synthesis of polyamides from diamines of the fluorene series

Aromatic polyamides were prepared by polycondensation of isophthaloyl chloride and 2,7-diaminofluorene, 2,7-dimainofluorenone, or 2,5-diaminofluorenone in AcNMe2 or N-methyl-2-pyrrolidinone at 20 deg - 30 deg for 1.5-2 hr. Isophthaloyl chloride-2,5-diaminofluorenone copolymer 39609-29-51 was sol. in AcNMe2, N-methyl-2-pyrrolidinone, DMF, and hexamethylphosphoramide, whereas isophthaloyl chloride-2,7-diamino-fluorene copolymer 39609-30-3 and isophthaloyl chloride-2,7-diamino-fluorenone copolymer 39609-31-0 were not sol. in the solvents cited. The aromatic polyamides revealed thixotropic properties in 0.5% solutions in H2SO4

STUDY OF STRESSED-DEFORMED STATE OF THE POLYGONAL ARCH COVERINGS OF WOOD

In this work the use of wooden I-beams with OSB wall as the load bearing elements for polygonal arch coverings of buildings of various spans are considered. Special steel connecting pieces can shape the polygonal arch coverings. Calculations of the constructions with a span of 12 and 18 meters and an analysis of their stress-strain state are given.In this work the use of wooden I-beams with OSB wall as the load bearing elements for polygonal arch coverings of buildings of various spans are considered. Special steel connecting pieces can shape the polygonal arch coverings. Calculations of the constructions with a span of 12 and 18 meters and an analysis of their stress-strain state are given

Late results of embolization of a portal hepatic vein branches in patients, suffering extended hepatic tumors

Objective. To analyze late results of preoperative  embolization of the portal hepatic vein branches (EPHVB) in patients, suffering extended hepatic tumors and extremely border-like small calculated residual hepatic volume(CRHV). Маterials and methods. From 2004 to 2014 yr the extended hepatic resection (HER) was performed in 285 patients, to whom EPHVB was applied (the main group), аnd in 353 patients as well, but without endovascular preparation (control group). In both groups dynamics of laboratory indices, structure of complications and lethality, late survival were studied. Results. In the main group a trustworthily lower rate of an acute hepatic insufficiency and connected with a lower postoperative lethality - accordingly 2.3 and 4.6%, comparing with a control group - 9.3 and 8.8%, were suggested. The laboratory data dynamics have witnessed a lesser intensiveness of postoperative hepatocytolysis and lesser degree of the hepatic synthetic function lowering in the main group, what have confirmed a better functional adaptation of hepatic residual in patients, to whom preoperative EPHVB was applied. Conclusion. Preoperative EPHVB permits to lower the postoperative complications and lethality rate in patients, suffering hepatic tumors, due to better functional adaptation of hepatic residual

Размер и форма частиц полипиррола в водных растворах поли-( N-винилпирролидона)

Based on the IR spectroscopy data and on the analysis of rheological characteristics of polypyrrole aqueous suspension stabilized with poly-(N-vinylpyrrolidone) we conjecture that a physical lattice composed with poly-(N-vinylpyrrolidone) is formed, where the lattice points are the polypyrrole chain aggregates interlaced with poly-(N-vinylpyrrolidone) chains. It was shown that there is a hydrogen bond between the constitutional repeating units of poly-(N-vinylpyrrolidone) and polypyrrole. It was determined that the size of the particles of the disperse phase decreases with the increase of poly-(N-vinylpyrrolidone) molecular weight. It was also determined that the size of particles increases with the increase of the mass fraction of polypyrrole aqueous suspension. It was shown that the disperse phase particles are rod-like, and the increase of molecular weight of poly-(N-vinylpyrrolidone) in an aqueous solution results in additional lengthwise stretching of particles. It was also shown that the viscosity of the stabilized poly-(N-vinylpyrrolidone) aqueous suspension follows the Einstein law.На основании данных ИК-спектроскопии и анализа реологических характеристик водной суспензии полипиррола, стабилизированной поли-( N -винилпирролидоном), выдвинуто предположение об образовании физической сетки, формируемой цепями поли-( N -винилпирролидона), узлами которой являются агрегаты цепей полипиррола, переплетенные с цепями поли-( N -винилпирролидона). Установлено уменьшение размера частиц дисперсной фазы при увеличении молекулярной массы поли-( N -винилпирролидона)

Хирургические аспекты формирования кишечных стом в онкологии. Обзор литературы

The formation of intestinal stoma is performed during routine and emergency operations. This review provides a brief historical overview of the main stages of development of methods colo- and ileostomy. The article presents indications, as well as possible complications that may happen during operative treatment. It is occurred that there is little evidentiary material of colo- or ileostomy in evaluating complications that are associated with the various surgical methods of intestinal stoma formation. The purpose of this review is to summarize the current data on stoma formation and determine the method to use.Формирование кишечной стомы выполняется при плановых и экстренных операциях. В работе представлен краткий исторический обзор основных этапов развития методов формирования коло- и илеостом. Приведены показания, а также возможные осложнения при выполнении данного оперативного лечения. При оценке осложнений, связанных с формированием кишечной стомы, и определении преимуществ различных хирургических методов выявлено, что доказательных данных о преимуществе коло- или илеостом накоплено мало. Целями данного обзора является обобщение современных данных о кишечных стомах и определение метода выбора для применения в практике

Кинетика и механизм окисления 2,4,6-триметиланилина

The kinetics of oxidation of 2,4,6-trimethylaniline hydrochloride with ammonia peroxydisulfate in an aqueous solution was studied by the potentiometric method. It was shown that the reaction proceeds as the second order process. The rate constants of one-electron transfer from 2,4,6-trimethylaniline molecule to peroxydisulfate ion were determined and are 1.46, 2.3, and 3.17 l/(mol.sec) at 30, 35 and 40° С , respectively. The activation energy of one-electron transfer from 2,4,6-trimethylaniline molecule to peroxydisulfate ion is 61 kJ/mol, the entropy of activation is –63 J/(mol К ), and the enthalpy of activation is 58.5kJ/mol. It was determined that 2,4,6-trimethylaniline is not prone to oxidative polymerization. This indicates that cation-radicals of aromatic amines which act as active centers of aniline oxidative polymerization are formed. The fact that there is no autoacceleration during oxidation of 2,4,6-trimethylaniline hydrochloride indicates that the oxidative polymerization of aniline is an autocatalytical process.Потенциометрическим методом исследована кинетика окисления 2,4,6-триметиланилина под действием пероксидисульфата аммония в водном растворе. Показано, что скорость реакции подчиняется уравнению второго порядка. Определены константы скорости и энергия активации окисления 2,4,6-триметиланилина, а также предложен механизм реакции

КИНЕТИКА И МЕХАНИЗМ ОКИСЛИТЕЛЬНОЙ ПОЛИМЕРИЗАЦИИ 2-МЕТИЛАНИЛИНА

The kinetics of oxidative polymerization of 2-methylaniline in hydrochloric acid aqueous solution in the presence of ammonium peroxydisulfate as the oxidant was studied. The presence of autocatalysis was demonstrated, and the reaction mechanism was suggested. On the basis of the mechanism a kinetic model of oxidative polymerization of 2-methylaniline was built. The model is in satisfactory agreement with the experimental results.И сследована кинетика окислительной полимеризации 2-метиланилина в солянокислом водном растворе в присутствии пероксидисульфата аммония в качестве окислителя. Показано наличие автокатализа, предложен механизм реакции. На основании механизма построена кинетическая модель окислительной полимеризации 2-метиланилина, находящаяся в удовлетворительном соот-ветствии с результатами эксперимента