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Aim. To cоmpare the results оf infra-spinal reconstructions of the lower extremities with the formatiоn of a distal anastomоsis below the knee joint fissure with the use of a bioprosthesis and autovein in critical limb ischemia (CLI).Methods. The hospital results of revascularization were retrospectively analyzed in 53 patients with CLI who underwent primary prosthetics of the femoral-popliteal segment with the fоrmation of a distal anastomоsis belоw the knee joint gap. All patients, depending on the prоsthetic material used, were divided into two groups: 1) autovein was used as a prosthesis (39.6%, n = 21)) and 2) a bioprosthesis was used (“KemAngioprosthesis” closed joint-stock company “NeoCor” Kemerovo, Russia) (60.4%, n = 32).Results. In the early postoperative period, thrombosis developed in group 1 in 7 cases (33.3%): in 5 patients – on the first day after the surgery; 2 out of 5 patients were with chronic arterial insufficiency (CAI) of the fourth degree, 1 was with acute arterial insufficiency of the first degree, and 2 patients with the third degree of CAI. In group 2, there were 6 prosthetic thrombosis (18.7%), 4 cases of which developed thrombosis on the first day, 3 patients with CAI of the fourth degree and 1 case with acute arterial insufficiency of the second degree.Conclusion. The application of infra-lingual reconstructions using bioprostheses is quite effective and safe in patients with CLI, in particular with purulent-necrotic trophic processes when a suitable autovein to be used as a prosthetic material is absent.

This article analyzes the methods of searching for similar images in a large database, examines in detail the search for images using perceptual hashes with Hamming distance calculation, using a convolutional neural network and using these methods together. The analysis of the speed and accuracy of the method of searching for similar images by comparing perceptual hashes, the analysis of the accuracy of image classification using a convolutional neural network, the analysis of speed and accuracy when they are used together, including with small changes in images (cropping, rotation, contrast change, sharpness change). According to the results of the study, it was revealed that the joint use of the perceptual hash comparison method and the classification method using a neural network is the most effective.

The transparency coefficients of a semiconductor structure consisting of alternating asymmetric potential barriers and wells, where the Bastard condition is taken into account, are calculated. It is shown that in the structure, an oscillation of the transmission coefficient of electrons depending on their energy is observed, which is caused by the interference of the de Broglie waves coming to the barrier and reflected from the potential barrier. The electronic states of a multilayer semiconductor structure consisting of alternating potential wells and barriers are analyzed.

The spectral and temperature dependences of the one-photon absorption coefficient of polarized radiation are calculated and the linear-circular dichroism in p-type tellurium is investigated. The coherent saturation of the hole final state is taken into account.

In the Russian Federation in recent years, there has been an increase in the incidence of colorectal cancer. The probability of the disease with colorectal cancer increases after 40 years and sharply increases after 50 years. Aim. To study the age-specific features of the prevalence of colorectal cancer in the Republic of Bashkortostan. Materials and methods. As the research materials, the form of Federal statistical observation No. 7 “Information on the incidence of malignant neoplasms” was used in the Republic of Bashkortostan for 2008-2016. The indicators of the incidence of colorectal and rectum cancer per 100 thousand of the population, depending on age and sex, are calculated. Results and discussion. The lowest incidence of colorectal cancer was observed in the age group up to 30 years, the largest - at the age of 70 years and older. For the years 2008-2016 the proportion of patients younger than 50 years with newly diagnosed colon cancer increased from 8.1% to 9.0% and rectum from 7.2% to 8.1%. In this age group there was an increase in primary incidence of colorectal cancer among men by 84.0%, among women by 50.0%, rectal cancer by 54.2% and 68.0%, respectively. The decrease in the incidence of colorectal cancer in the age group of 70 years and older. The average annual incidence rate of colorectal cancer was higher among men than among women in the age groups 50-59, 60-69 years and 70 years and older, rectal cancer in all age groups, with differences increasing with age. During the observation period, the mean age of patients with newly diagnosed colon cancer was reduced by 1.5 years, rectal by 1.3 years. Among patients with colorectal cancer living in urban areas, the average age was higher than in rural areas. The conclusion. The revealed sex-age features of the prevalence of colorectal cancer were used in the development of measures to improve medical care for patients.

The reaction of 2-(1-cyclohexen-1-yl)aniline and -6-methylaniline with phthalic anhydride has afforded 2-(2-cyclohex-1-en-1-ylphenyl)- and 2-(2-cyclohex-1-en-1-ylphenyl)-6-methylphenyl)-1H-isoindole-1,3(2H)-diones. The reaction of the obtained isoindole-1,3-diones with bromine in dichloromethane in the presence of sodium bicarbonate has led to the formation of the product of pseudo-allylic halogenation. Replacement of the halogen atom by methoxy group has been performed by keeping 2-[2-(6-bromocyclohex-1-en-1-ylphenyl)-6-methylphenyl)]-1H-isoindole-1,3(2H)-dione in a methanolic solution in the presence of NaHCO3. The reaction of 2-(2-cyclohex-1-en-1-yl-6-methylphenyl)-1H-isoindole-1,3(2H)-dione with molecular bromine in the presence of methanol has given a co-halogenation product, whereas the dibromination product has been obtained in the presence of octyl alcohol.

The reaction of 1-alkenes with C2D5MgBr in the presence of TaCl5 has been studied. Basing on the distribution of the deuterium label in the alkyl chain of the regioisomeric organomagnesium compounds, a tentative mechanism of their formation as key intermediates of 3-substituted tantalocyclopentanes has been proposed. The energy profiles of the reactions of carbomagnesation and β-reductive magnesaethylation of 1-alkenes have been obtained using the DFT method.

Analysis of the results of emergency carotid endarterectomy (CEE) against the background of internal carotid artery (ICA) thrombosis in the acute period of acute cerebrovascular accident (ACVA) in patients with COVID-19. During the COVID-19 pandemic (April 1, 2020-May 1, 2021), 43 patients with ICA thrombosis and a positive polymerase chain reaction (PCR) result for SARS-CoV-2 were included in this prospective study. In all cases, CEE was performed in the acutest period of ACVA. These patients were included in group 1. The comparison group was represented by 89 patients who underwent CEE in the acute period of stroke, in the period before the COVID-19 pandemic (April 1, 2019-March 1, 2020). According to laboratory parameters, patients with COVID-19 had severe coagulopathy (with an increase in D-dimer: 3832 ± 627.2 ng/mL, fibrinogen: 12.6 ± 3.1 g/L, prothrombin: 155.7 ± 10, 2%), inflammatory syndrome (increased ferritin: 646.2 ± 56.1 ng/mL, C-reactive protein: 161.3 ± 17.2 mg/L, interleukin-6: 183.3 ± 51.7 pg/mL, leukocytosis: 27.3 ± 1.7 10E9/L). In the hospital postoperative period, the groups were comparable in terms of the incidence of deaths (group 1: 2.3%, n = 1; group 2: 1.1%, n = 1; P= 0.81; OR=2.09; 95 % CI = 0.12-34.3) myocardial infarction (group 1: 2.3%, n = 1; group 2: 0%; P= 0.7; OR = 6.3; 95% CI = 0.25-158.5), CVA (group 1: 2.3%, n = 1; group 2: 2.2%, n = 2; P= 0.55; OR = 1.03; 95% CI = 0,.09-11.7). ICA thrombosis and hemorrhagic transformations were not recorded. However, due to severe coagulopathy with ongoing anticoagulant/antiplatelet therapy, patients with COVID-19 more often developed bleeding in the operation area (group 1: 11.6%, n = 5; group 2: 1.1%, n = 1; P= 0.02; OR = 11.5; 95% CI = 1.3-102.5). In all cases, the flow of hemorrhagic discharge came from the drainage localized in the subcutaneous fat. This made it possible to remove skin sutures in a dressing room, suturing the source of bleeding and applying secondary sutures under local anesthesia. Emergency CEE in the acute period of stroke is an effective and safe method of cerebral revascularization in case of ICA thrombosis in conditions of COVID-19.

The aspects of chemical desactivation of the pyrophoric sediments using sulfoxides on the oil production facilities during the exploitation of the vertical cylindrical vessels (VCV), which are intended for containing sulphurous oils, are studied in this article. It is found out that sulfoxides, either individual substances or their mixtures, can effectively passivate pyrophoric iron sulphides. The laboratory express-method for separation the pyrophoric sediments, containing pyrophoric iron is also developed.

The intensive development of the gas industry and the tension in the operation of gas transportation equipment make it necessary to solve the problems of developing and introducing new energy-saving gas transportation technologies. The authors carried out simulation of the gas pipeline and laboratory studies, as well as recalculation of the parameters of the experimental plant in relation to the main gas pipelines. It is concluded that the developed twisting device is effective.

The results of studying the fire foams’ modification using organosilicone compounds are presented in this article. The results of comparative fighting flammable liquid fires (diesel fuel) using non-modified foam and modified foam are also studied. It is shown that fire fighting using foam, modified with organosilicone compounds is much more effective, because of the increasing isolating capacity of such foam due to high-solidifying formation of foam which prevent the liquid vapors from getting in the area of chemical reactions and also isolate the flammable liquid from the oxygen of the air. Such a result is possible due to the presence of the mixture of solutions of foaming agent and the organosilicone modifying compound in the structure of the foam – tethraethyl silicate (TES). The results of the study confirm the perspective of using the organic compounds of the silica for improvement the fire extinguishing properties of the foam and its further applying for the fighting with flammable liquid fire.

In the article, the application algorithms of neural network methods for determining the lithological composition of a well bore according to logging data are studied by training based on the analysis of the correspondence of logs to the available expert opinion. Specialized algorithms for processing the results of network operation have been developed to increase the information content of a signal produced by a neural network and to increase the reliability of recognition.

Studies have been carried out on the effect of an electric breakdown of a dielectric on flame suppression by an electric field of high voltage. In the course of research in the event of electric breakdown of air, the quenching efficiency was reduced to zero. This effect occurs due to the drop in electrical tension between the electrodes. The electrical breakdown in dielectrics when extinguishing a flame is due to the presence of a certain number of ions and electrons, which under the action of the electric field move to the anode. It is established that the electrical strength of the material exerts the greatest influence on the outcome of experimental studies on extinguishing a fire by an electromagnetic field. Therefore, increasing the values of the electrical strength of the material (dielectric), it is possible to exclude the possibility of electrical breakdown. If glass and electrotechnical porcelain are used as dielectrics on electrodes, the boundaries of the investigation flame process by an electric field of high tension will expand. Studies have shown that an electric breakdown has a negative effect on flame suppression by an electric field of high tension. The probability of electrical breakdown is influenced by such parameters as: the distance between the electrodes (the probability of breakdown increases with decreasing distance), atmospheric pressure, air humidity (the probability of electric breakdown decreases with decreasing air humidity), the strength of the material (with an increase in the strength of the material, the probability of breakdown decreases ) and voltage at the electrodes (with increasing voltage, the probability of breakdown increases). In the course of the research it was established that an increase in the electrical strength of the electrodes will allow to conduct studies with a voltage of up to 20,000 kV without the occurrence of electrical breakdown.

Aim. To analyze the immediate and long-term outcomes of eversion and conventional carotid endarterectomy (CE) with patch angioplasty.Material and methods. For the period from February 1, 2006 to September 1, 2021, the present retrospective multicenter open comparative study included 25106 patients who underwent CE. Depending on the technique of operation, the following groups were formed: group 1 (n=18362) — eversion CE; group 2 (n=6744) — conventional CE with patch angioplasty. The long-term follow-up period was 124,7±53,8 months.Results. In the hospital postoperative period, the groups were comparable in incidence of all complications: lethal outcome (group 1: 0,19%, n=36; group 2: 0,17%, n=12; p=0,89; odds ratio (OR) =1,1; 95% confidence interval (CI) =0,57- 2,11); myocardial infarction (MI) (group 1: 0,15%, n=28; group 2: 0,13%, n=9; p=0,87; OR=1,14; 95% CI=0,53-2,42); stroke (group 1: 0,33%, n=62; group 2: 0,4%, n=27; p=0,53; OR=0,84; 95% CI=0,53-1,32); bleeding with hematoma formation (group 1: 0,39%, n=73; group 2: 0,41%, n=28; p=0,93; OR=0,95; 95% CI=0,61-1,48); internal carotid artery (ICA) thrombosis (group 1: 0,05%, n=11; group 2: 0,07%, n=5, p=0,9; OR=0,8; 95% CI=0,28-2,32). In the long-term follow-up, the groups were comparable only in MI incidence: group 1: 0,56%, n=103; group 2: 0,66%, n=45; p=0,37; OR=0,84; 95% CI=0,59-1,19. All other complications were more frequent after conventional CE with patch angioplasty: all-cause death (group 1: 2,7%, n=492; group 2: 9,1%, n=616; p60%, requiring re-revascularization (group 1: 1,6%, n=296; group 2: 12,6%, n=851; pConclusion. Conventional CE with patch angioplasty is not prefer for cerebral revascularization in the presence of hemodynamically significant ICA stenosis due to the high prevalence of deaths, stroke, and ICA restenosis in the long-term follow-up.

The information on arguments of an oil reservoir to a well test from the point of view of the Bayesian inference are express through even allocation of odds in room of arguments. In article application of confidential spacing for a quantitative appraisal of the information receive from the analysis of results of well test which one are us for upgrading of allocations of odds are offered. Use of confidential spacing for an appraisal of a correctness of a choice of a laboratory formation are show.

The information on unknown parameters of an oil formation can be express through a multivariate distribution of probabilities in space of parameters. A new quantitative method for carrying out of the discriminant analysis of models of an oil formation on the basis of hydrodynamic slits by sequential prediction of the probabilities of pressure modification is offered in this paper. Investigation of look-ahead probability for several models of the slit formation was conducted. The developed method can be used as a universal tool for carrying out of the discriminant analysis of models irrespective of the number of parameters.

To analyze the dynamics of systolic blood pressure (SBP) and the results of various types of carotid endarterectomy (CEE) in patients with resistant arterial hypertension (RAH).The study included 1577 patients with hemodynamically significant stenosis of the internal carotid artery (ICA) and RAH for more than 3 years. Patients were enrolled from January 2014 to December 2020. Depending on the implemented revascularization strategy, 5 groups were formed: group 1 (In the postoperative period, no significant differences were obtained in the frequency of deaths (0.34% for group 1; 0.63% for group 2; 0% for groups 3, 4 and 5), myocardial infarction (0.34%, 0.84%, 1.83, 0.85%, 0.33%, respectively); ischemic stroke (0.34%, 1.27%, 0.91%, 0.85%, 0.17%, respectively), hemorrhagic transformation (0%, 0.84%, 0.91%, 0.85%, 0%, respectively). However, according to the frequency of the combined endpoint (death + myocardial infarction + ischemic stroke + hemorrhagic transformation), the lowest rates were observed in the group of classical carotid endarterectomy with plasty of the reconstruction zone with a patch and glomus-sparing CEE (1.03%, 3.6%, 3.67%, 2.56%, 0.5%, respectively). This is due to the absence of cases of labile AH and hypertensive crises among patients of groups 1 and 5, which was ensured by the preservation of carotid glomus (CG). As a result, the number of patients with 2 and 3 degrees of hypertension in these groups decreased statistically significantly. The vast majority of patients after these operations achieved a stable target SBP. In groups 2, 3, and 4, there was a statistically significant increase in the number of patients with 2 and 3 degrees of AH, which is associated with excision of the CG.Classical CEE and glomus-sparing CEE techniques make it possible to achieve a stable target SBP level in patients with RAH as a result of CG preservation. Removal or traumatization of the latter during eversional CEE, the formation of a new bifurcation, autoarterial reconstruction is accompanied by the development of labile hypertension, an increase in the degree of hypertension and a high risk of hemorrhagic transformation in the brain. Thus, the most effective and safe types of CEE in the presence of RAH are classical CEE with plasty of the reconstruction zone with a patch and glomus-sparing CEE.Анализ динамики систолического артериального давления (САД) и результатов различных видов каротидной эндартерэктомии (КЭЭ) у пациентов с резистентной артериальной гипертензией (АГ).В данное исследование за период с января 2014 по декабрь 2020 гг. вошли 1577 пациентов с гемодинамически значимым стенозом внутренней сонной артерии (ВСА) и резистентной АГ длительностью более 3 лет. В зависимости от реализованной стратегии реваскуляризации было сформировано пять групп: 1-я группа: 18,3% (В послеоперационном периоде значимых различий не было получено по частоте летальных исходов (1-я группа — 0,34%; 2-я группа — 0,63%; 3-я группа — 0%; 4-я группа — 0%; 5-я группа — 0%), инфаркта миокарда (0,34%; 0,84%; 1,83%; 0,85%; 0,33% соответственно), ишемического инсульта (0,34%; 1,27%; 0,91%; 0,85%; 0,17% соответственно), геморрагической трансформации (0%; 0,84%; 0,91%; 0,85%; 0% соответственно). Однако по частоте комбинированной конечной точки (смерть + инфаркт миокарда + ишемический инсульт + геморрагическая трансформация) в группе классической КЭЭ с пластикой зоны реконструкции заплатой и гломус-сберегающих КЭЭ наблюдались наименьшие показатели (1,03%; 3,6%; 3,67%; 2,56%; 0,5% соответственно). Это обусловлено отсутствием случаев лабильной АГ и гипертонических кризов среди пациентов 1-й и 5-й групп, что было обеспечено сохранением каротидного гломуса. В результате этого количество пациентов со 2-й и 3-й степенями АГ в этих группах статистически значимо уменьшилось. Подавляющее большинство больных после данных операций достигло стабильного целевого уровня САД. Во 2-й, 3-й и 4-й группах отмечено статистически значимое увеличение числа пациентов со 2-й и 3-й степенями АГ, что связано с иссечением каротидного гломуса.Классическая КЭЭ и гломус-сберегающие техники КЭЭ позволяют достичь стабильного целевого уровня САД у пациентов с резистентной АГ в результате сохранения каротидного гломуса. Удаление или травматизация последнего при эверсионной КЭЭ, формировании новой бифуркации, аутоартериальной реконструкции сопровождается развитием лабильной АГ, повышением степени АГ и высоким риском формирования геморрагической трансформации. Таким образом, наиболее эффективными и безопасными видами КЭЭ при наличии резистентной АГ являются классическая КЭЭ с пластикой зоны реконструкции заплатой и гломус-сберегающие КЭЭ.

This work studies the temperature regime of the wall while up and down moving of the unsaturated liquid in the vertical tube at pressure below critical and influence of free convection on the heat transfer. The boundary of influence free convection on heat transfer is determined and summarized as a criterion equation.

To compare long-term outcomes in patients after carotid endarterectomy and those who refused surgical correction and received only conservative treatment.There were 1035 carotid endarterectomies performed at the Kemerovo Regional Clinical Hospital and Kemerovo Regional Clinical Cardiology Dispensary for the period 2014-2017. Surgery was refused by 136 patients for the same time. Thus, two groups of patients were formed: 1 - carotid endarterectomy group; 2 - conservative treatment group.significant carotid stenosis, absence of severe neurological deficit (over 25 scores by the National Institutes of Health Stroke Scale), absence of concomitant diseases limiting long-term follow-up.Lethal outcome (p=0.0038) and fatal acute cerebrovascular accident (p=0.0005) were significantly more common in the 2Preventive role of carotid endarterectomy was convincingly proved in comparison with drug therapy regarding mortality and fatal ischemic stroke in patients with significant carotid stenoses within 2.5 years of follow-up period.Цель исследования - сравнение отдаленных результатов у пациентов после каротидной эндартерэктомии и больных, отказавшихся от хирургической коррекции и получающих только консервативное лечение. Материал и методы. За период 2014-2017 гг. в Кемеровской областной клинической больнице и Кемеровском областном клиническом кардиологическом диспансере выполнено 1035 каротидных эндартерэктомий. Также за тот же период времени выявлено 136 отказов пациентов от операции. Таким образом, было сформировано две группы пациентов: 1-я - группа каротидной эндартерэктомии; 2-я - группа отказов от операции с консервативной тактикой лечения. Критериями включения в исследование стали: наличие гемодинамически значимых стенозов сонных артерий (более 60%), отсутствие тяжелого неврологического дефицита (более 25 баллов по шкале National Institutes of Health Stroke Scale), отсутствие коморбидных заболеваний, лимитирующих наблюдение в отдаленном периоде. Результаты. В отдаленном периоде наблюдения в группе консервативной терапии статистически чаще выявлялись летальный исход (р=0,0038) и летальное острое нарушение мозгового кровообращения (р=0,0005). Таким образом, комбинированная конечная точка принимала наибольшие значения у пациентов, отказавшихся от операции, по сравнению с пациентами, получившими хирургическое лечение (р=0,000). Необходимо заметить, что среди 9 (6,6%) больных с консервативной стратегией лечения через 10,8±2,5 мес после отказа от хирургии возник впервые выявленный ишемический инсульт, по поводу чего они впоследствии были госпитализированы для проведения каротидной эндартерэктомии. Заключение. В результате проведенного исследования убедительно доказана превентивная роль каротидной эндартерэктомии в сравнении с медикаментозной терапией в отношении смерти и фатального ишемического инсульта у пациентов с гемодинамически значимыми стенозами внутренних сонных артерий на протяжении 2,5 лет наблюдения.

The TaCl 5 -mediated reaction between monosubstituted alkenes and Et 2 Zn affords 3-(R-substituted)-n-butylzincs in high yield (up to 92%) and regioselectivity. Organozinc reagents bearing a longer alkyl chain (R = Pr n , Bu n , Am n , Hex n, ) react with 1-alkenes in the presence of TaCl 5 as the catalyst to give two types of organozinc compound having iso -alkyl structure. The probable mechanism of the carbozincation reaction implies the formation of β-substituted and β,β'-disubstituted tantalacyclopentanes as the key intermediates. The thermodynamic probability of the mechanistic elementary stages for the ethylzincation of terminal alkenes has been estimated using DFT PBE/SBK method Keywords : Catalysis; Organozin с compounds; 1-Alkenes; Carbozincation; Tantalacyclopentanes; DFT calculations 1. Introduction ∗ Corresponding author. Tel./fax: +7 347 2842750. E-mail address: Sultanov55@mail.ru (R.M. Sultanov). Leave this area blank for abstract info. The tantalum-catalyzed carbozincation of 1-alkenes with zinc dialkyls

Electric and magnetic tuning of phase, frequency, and delay time of electromagnetic-spin waves in thin-film layered multiferroic structure (metal-dielectric gap-ferroelectric material-hexaferrite-dielectric substrate) is numerically simulated. The results are used to demonstrate prospects for application of layered multiferroic hexaferrite-ferroelectric structures in the construction of basically new devices for generation and processing of microwave signals under dual (electric and magnetic) tuning of the working characteristics in the subterahertz frequency range.

The paper deals with the process of creating a system of modeling the video sequence of the flight of an unmanned aerial vehicle for the tasks of testing visual navigation algorithms. This system can be used when it is impossible to carry out the flight and to obtain real images of the terrain from the onboard camera of the unmanned aerial vehicle. The basis for the generation of images is the base image that can be a satellite image or an orthophoto. The input data are the control points through which the flight, altitude and characteristics of the aircraft, such as flight speed, should be simulated. The control points are connected by straight lines, forming a flight route that determines the flight area on the base image. Based on the altitude and flight speed of the unmanned aerial vehicle, the scale of the output images is calculated, taking into account the resolution of the base image. Using the obtained scale and flight speed of the aircraft, the displacement of the coordinates is calculated. On the basis of control points and coordinate displacement, intermediate points are formed, which determine the flight path. For each point, the direction of flight of the unmanned aerial vehicle is formed, using the angle of rotation along the circle. If there are several control points, the trajectory is smoothed by gradually changing the angle of rotation at each point. The points of the obtained trajectory are used as the centers of the generated flight images, which are transformed according to the direction of movement of the unmanned aerial vehicle, using affine transformations. EXIF format metadata containing the coordinates of the image and flight characteristics are generated for the images. As a result, a video sequence is formed for each intermediate point with flight characteristics located in the metadata of the image file. In conclusion, the paper provides examples of the use of the obtained images and describes possible improvements of the developed system.

Carboalumination of 1-alkenes (1-hexene, 1-octene, 1-decene) with Et 3 Al in the presence of catalytic amounts of TaCl 5 results in a mixture of 2-( R -substituted)- and 3-( R -substituted)- n -butylaluminums (1:1 ratio) in total yields of 75–85%. The TaCl 5 -catalyzed reaction of bicyclo[2.2.1]hept-2-ene, endo -tricyclo[5.2.1.0 2,6 ]deca-3,8-diene, and ( exo / endo )-5-methylbicyclo[2.1.1]hept-2-ene with Et 3 Al leads to the formation of diethyl[2- exo -(2′-norbornylethyl)]aluminums in high yields. DFT calculations confirm the thermodynamic preference of the final exo product. The multistep reaction mechanisms for the formation of the resultant organoaluminums through tantalacyclopentanes as key intermediates are also discussed.

The stereoselective carbomagnesiation reaction of bicyclo[2.2.1]hept-2-ene, endo -tricyclo[5.2.1.0 2,6 ]deca-3,8-diene, and exo – endo -5-methylbicyclo[2.1.1]hept-2-ene with EtMgX, where X = Cl or Et, occurs in the presence of catalytic amounts of TaCl 5 to give chloro- and ethyl[2- exo -(2′-norbornylethyl)]magnesiums in high yields. The multistep reaction mechanism involving norbornene and ethylene through tantalacyclopentanes as key intermediates is also postulated. DFT calculations confirm the thermodynamic preference for the resulting exo product.

It has been established that the heat transfer of toluene in a turbulent regime of motion and at a supercritical pressure in a horizontally arranged bent pipe changes nonuniformly along the perimeter of the cross section. The basic factors are free convection and inertial forces. Computational equations for the heat-transfer coefficient are proposed.

Tantalum-catalyzed reaction of organomagnesium compounds (OMCs), bearing normal alkyl radicals, with 1-alkenes to afford novel iso -alkylmagnesiums has been systematically studied for the first time. The probable mechanism of the reaction implying the intermediate formation of β,β′-dialkyl substituted tantalacyclopentanes is discussed.