Hemilability of phosphine-thioether ligands coordinated to trinuclear Mo3S4 cluster and its effect on hydrogenation catalysis

Ligand-exchange reactions of [Mo3S4(tu)8(H2O)]Cl44H2O (tu = thiourea) with (PhCH2CH2)2PCH2CH2SR ligands, where R = Ph (PS1), pentyl (PS2) or Pr (PS3) afford new complexes isolated as [Mo3S4Cl3(PS1)3]PF6 ([1]PF6), [Mo3S4Cl3(PS2)3]PF6 ([2]PF6) and [Mo3S4Cl3(PS3)3]PF6 ([3]PF6) salts in 30-50% yields as the major reaction products. The crystal structures of [1]PF6 and [2]PF6 were determined by X-ray diffraction (XRD) analysis. Each of the three phosphine-thioether ligands is coordinated in a bidentate chelating mode to a different molybdenum atom of the Mo3S4 trinuclear cluster, herewith all the phosphorus atoms of the phosphino-thioether ligand are located trans to the capping sulfur (3-S). A second product that forms in the reaction of [Mo3S4(tu)8(H2O)]Cl44H2O with PS1 corresponds to the neutral [Mo3S4Cl4(PS1)2(PS1*)] complex. Its XRD analysis reveals both bidentate (PS1) and monodentate (PS1*) coordinating modes of the same ligand. In the latter mode the phosphinethioether is coordinated to a Mo atom only via the P atom. All compounds were characterized by 1H, 31P{1H} NMR, electrospray-ionization (ESI) mass spectrometry and cyclic voltammetry (CV). Reactions of [1]PF6, [2]PF6 and [3]PF6 with an excess of Bu4NCl in CD2Cl2 were followed by 31P{1H} NMR. The spectra indicate equilibrium between cationic [Mo3S4Cl3(PSn)3] + and neutral [Mo3S4Cl4(PSn)2(PSn*)] (n = 1, 2) species. The equilibrium constants were determined as 2.5 ± 0.2103 , 43 ± 2 М -1 and 30 ± 2 М -1 (at 25°C) for [1]PF6, [2]PF6 and [3]PF6, indicating quantitative differences in hemilabile behavior of the phosphino-thioether ligands, depending on the substituent at sulfur. Clusters [1]PF6, [2]PF6 and [3]PF6 were tested as catalysts in reduction of nitrobenzene to aniline with Ph2SiH2 under mild conditions. Significant differencies in the catalytic activity were observed, which can be attributed to different hemilabile behavior of the PS1 and PS2/PS3 ligands

Assessment of the possibility for large-scale 238Pu production in a VVER-1000 power reactor

The paper presents the estimates for the possibility for large-scale production of 238Pu in the core of a VVER-1000 power reactor. The Np-fraction of minor actinides extracted from transuranic radioactive waste is proposed to be used as the starting material. The irradiation device with NpO2 fuel elements is installed at the reactor core center. The NpO2 fuel lattice pitch is varied and the irradiation device is surrounded by a heavy moderator layer to create the best possible spectral conditions for large-scale production (~ 3 kg/year) of conditioned plutonium with the required isotopic composition (not less than 85% of 238Pu and not more than 2 ppm of 236Pu). Plutonium with such isotopic composition can be used as the thermal source in thermoelectric radioisotope generators and in cardiac pacemakers. It has been demonstrated that the estimated scale of the 238Pu production in a VVER-type power reactor exceeds considerably the existing scale of its production in research reactors

ВЛИЯНИЕ МЕТОДА АНЕСТЕЗИИ НА АКТИВНОСТЬ ПЕРЕКИСНОГО ОКИСЛЕНИЯ ЛИПИДОВ ПРИ КАРОТИДНОЙ ЭНДАРТЕРЭКТОМИИ

The objective of the study: to assess the effect of two types of general anesthesia on lipid peroxidation and to establish a correlation between the degree of its activation and the number of post-operative neurological disorders.Subjects and methods. 130 patients (84 men and 46 women) at the age from 48 to 68 years were examined, they all were admitted to hospital for carotid endarterectomy due to atherosclerosis of internal carotid artery. The blind envelopes method was used for randomization. The patients were divided into 2 groups. The control group included 20 practically healthy persons (the median age made 50 ± 2 years).Propofol was used for anesthesia in 60 patients (Group 1), while sevoflurane was used in 70 patients (Group 2). Student test was used for statistical processing of data. The critical significance level corresponded to p < 0.05. The groups were considered representative based on 12 attributes.During the surgery, the following parameters were monitored: oxidant and anti-oxidant statuses, markers of neuronal damage; post-operative neurological complications were assessed.Results. When comparing and assessing the rates of the general pro-oxidant activity and general anti-oxidant activity in the patients from both groups, the initial rates of oxidant and anti-oxidant statuses did not confidently differ, which can be explained by the homogeneity of the patients' examinations.The activation of general pro-oxidant activity and general anti-oxidant activity was higher in Group 1 at the moment of carotid clamping. The same tendency was observed during the restoration of cerebral blood flow.The intensity of lipid peroxidation activation correlated with the frequency of post-operative neurological disorders and it was lower in Group 2.Цель работы: определение влияния двух видов общей анестезии на перекисное окисление липидов и установление корреляционной зависимости между степенью его активации и числом послеоперационных неврологических расстройств.Материалы и методы. Обследовано 130 больных (84 мужчины и 46 женщин) в возрасте от 48 до 68 лет, поступивших в клинику для каротидной эндартерэктомии по поводу атеросклероза внутренней сонной артерии. Рандомизация проведена методом слепых конвертов. Больные разделены на две группы. Контрольную группу составили 20 практически здоровых человек (средний возраст – 50 ± 2 года).Для анестезии использовали пропофол у 60 больных (1-я группа), севофлуран – у 70 (2-я группа). Статистическую обработку данных выполняли с использованием критерия Стьюдента. Критический уровень достоверности соответствовал p < 0,05. По 12 признакам группы были репрезентативны.В процессе хирургического лечения в динамике контролировали показатели оксидантного и антиоксидантного статусов, маркеры нейронального повреждения, оценивали послеоперационные неврологические осложнения.Результаты. При сравнительной оценке показателей общей прооксидантной активности (ОПА) и общей антиоксидантной активности (ОАА) у больных обеих групп исходные показатели оксидантного и антиоксидантного статуса статистически достоверно не различались, что объясняется однородностью обследованных пациентов.Активация ОПА и ОАА на этапе наложения зажима на сонную артерию была выше в 1-й группе. Такая же тендиция сохранялась на этапе восстановления мозгового кровотока.Выраженность активации перекисного окисления липидов коррелировала с частотой послеоперационных неврологических расстройств и была меньшей во 2-й группе

ВЛИЯНИЕ МЕТОДА АНЕСТЕЗИИ НА ПОКАЗАТЕЛИ ЦЕНТРАЛЬНОЙ ГЕМОДИНАМИКИ И МОЗГОВОЙ КРОВОТОК ПРИ КАРОТИДНОЙ ЭНДАРТЕРЭКТОМИИ

The objective: to compare the impact of two methods of general anesthesia during carotid endarterectomy on central hemodynamics and cerebral blood flow in order to choose the best anaesthesiologic tactics. Materials and subjects. The total intravenous anesthesia (sedation with propofol, n = 60) and general combined anesthesia (sedation with sevoflurane, n = 60) were compared in 130 patients undergoing carotid endarterectomy. Parameters of central hemodynamics and cerebral blood circulation were investigated. Results. It was found out that anesthesia with sevoflurane supported an effective level of central hemodynamics and provided a higher level of cerebral blood flow and was associated with statistically significant (11.9%) reduction in the number of neurological complications versus anesthesia with propofol. Conclusion: Inhalation anesthesia with sevoflurane can be considered the choice of anesthesia in carotid endarterectomy. Цель: сравнительная оценка влияния двух методов общей анестезии каротидной эндартерэктомии на центральную гемодинамику и мозговой кровоток для выбора наиболее оптимальной тактики анестезиологического обеспечения. Материал и методы. У 130 пациентов с каротидной эндартерэктомией проведена сравнительная оценка тотальной внутривенной (седа- ция пропофолом, n = 60) и общей комбинированной (выключение сознания севофлураном, n = 70) анестезии. Исследовали параметры центральной гемодинамики, мозгового кровообращения. Результаты. Показано, что анестезия с использованием севофлурана поддерживала оптимальный уровень параметров центральной гемодинамики, обеспечивала более высокий уровень мозгового кровотока и сопровождалась статистически значимым (на 11,9%) снижением числа неврологических осложнений по сравнению с анестезией на основе пропофола. Вывод. Ингаляционная анестезия севофлураном может считаться методом выбора при анестезиологическом обеспечении каротидной эндартерэктомии.

Life cycle of the centrally planned economy: Why Soviet growth rates peaked in the 1950s

The highest rates of growth of labor productivity in the Soviet Union were observed not in the 1930s (3% annually), but in the 1950s (6%). The TFP growth rates by decades increased from 0.6% annually in the 1930s to 2.8% in the 1950s and then fell monotonously becoming negative in the 1980s. The decade of 1950s was thus the “golden period” of Soviet economic growth. The patterns of Soviet growth of the 1950s in terms of growth accounting were very similar to the Japanese growth of the 1950s-70s and to Korean and Taiwanese growth in the 1960-80s – fast increases in labor productivity counterweighted the decline in capital productivity, so that the TFP increased markedly. However, high Soviet economic growth lasted only for a decade, whereas in East Asia it continued for three to four decades, propelling Japan, South Korea and Taiwan into the ranks of developed countries. This paper offers an explanation for the inverted U-shaped trajectory of labor productivity and TFP in centrally planned economies (CPEs). It is argued that CPEs under-invested into the replacement of the retiring elements of the fixed capital stock and over-invested into the expansion of production capacities. The task of renovating physical capital contradicted the short-run goal of fulfilling plan targets, and therefore Soviet planners preferred to invest in new capacities instead of upgrading the old ones. Hence, after the massive investment of the 1930s in the USSR, the highest productivity was achieved after the period equal to the average service life of fixed capital stock (about 20 years) – before there emerged a need for the massive investment into replacing retirement. Afterwards, the capital stock started to age rapidly reducing sharply capital productivity and lowering labor productivity and TFP growth rates