Application of Simplified Models to Qualitative Geotechnical Analysis

The paper describes an approach for qualifying soil-structure systems behavior, using simple numeric models – “geotoys”, reflecting the main features of the systems behavior and enabling numeric simulation of various case histories. Three case histories of major karstic sinkholes are analyzed to show that man-made structures above a karstic cavity prevent formation sinkhole. When plastic zones reach the structure periphery, the soil-structure system becomes unstable. Prior settlements could be negligible to serve as precursors. Another soil-footing-superstructure (SFSS) model is a 2D geotoy - an exact mathematical solution, used for multiple simulations (about 10,000) of SFSS sensitivity i.e., response to input parameters variations. The sensitivity was rated for each input-output pair [1]. The most interesting findings are the following: 1) SFSS stress state is very sensitive to soil strength parameters c and φ, which are responsible for formation of soil disruption zones (‘plastic zone’) under footing edges. 2) If a structure rests on a homogeneous soil base then it is practically insensitive to soil base compressibility i.e., soil modulus E variations. 3) 3D FEM analysis confirmed that 2D simulations can be used for qualitative SFSS analysis. 4) Geotoys can be used for case histories analysis, risk assessment, training practical intuition, education purposes and international exchange and cooperation

Shot noise in superconducting junctions with weak link formed by Anderson impurity

A theory is developed to study shot noise in superconducting (SAS) and hybrid (SAN) junctions with singly occupied Anderson impurity (A) as a weak link. The zero-frequency DC component of the shot noise spectral density is calculated at zero temperature as a function of the bias at different Coulomb repulsion strengths U, and show a remarkable structure resulting from combination of electron-electron interaction and Andreev reflections.Comment: 4 two column pages including 4 .eps figure

Adsorption of a random heteropolymer at a potential well revisited: location of transition point and design of sequences

The adsorption of an ideal heteropolymer loop at a potential point well is investigated within the frameworks of a standard random matrix theory. On the basis of semi-analytical/semi-numerical approach the histogram of transition points for the ensemble of quenched heteropolymer structures with bimodal symmetric distribution of types of chain's links is constructed. It is shown that the sequences having the transition points in the tail of the histogram display the correlations between nearest-neighbor monomers.Comment: 11 pages (revtex), 3 figure

Generalized Smoluchowski equation with correlation between clusters

In this paper we compute new reaction rates of the Smoluchowski equation which takes into account correlations. The new rate K = KMF + KC is the sum of two terms. The first term is the known Smoluchowski rate with the mean-field approximation. The second takes into account a correlation between clusters. For this purpose we introduce the average path of a cluster. We relate the length of this path to the reaction rate of the Smoluchowski equation. We solve the implicit dependence between the average path and the density of clusters. We show that this correlation length is the same for all clusters. Our result depends strongly on the spatial dimension d. The mean-field term KMFi,j = (Di + Dj)(rj + ri)d-2, which vanishes for d = 1 and is valid up to logarithmic correction for d = 2, is the usual rate found with the Smoluchowski model without correlation (where ri is the radius and Di is the diffusion constant of the cluster). We compute a new rate: the correlation rate K_{i,j}^{C} (D_i+D_j)(r_j+r_i)^{d-1}M{\big(\frac{d-1}{d_f}}\big) is valid for d \leq 1(where M(\alpha) = \sum+\infty i=1i\alphaNi is the moment of the density of clusters and df is the fractal dimension of the cluster). The result is valid for a large class of diffusion processes and mass radius relations. This approach confirms some analytical solutions in d 1 found with other methods. We also show Monte Carlo simulations which illustrate some exact new solvable models

Energy dependent counting statistics in diffusive superconducting tunnel junctions

We present an investigation of the energy dependence of the full charge counting statistics in diffusive normal-insulating-normal-insulating-superconducting junctions. It is found that the current in general is transported via a correlated transfer of pairs of electrons. Only in the case of strongly asymmetric tunnel barriers or energies much larger than the Thouless energy is the pair transfer uncorrelated. The second cumulant, the noise, is found to depend strongly on the applied voltage and temperature. For a junction resistance dominated by the tunnel barrier to the normal reservoir, the differential shot noise shows a double peak feature at voltages of the order of the Thouless energy, a signature of an ensemble averaged electron-hole resonance.Comment: 8 pages, 5 figure

ТРАНСРАДИАЛЬНЫЙ И ТРАНСФЕМОРАЛЬНЫЙ ДОСТУП ПРИ КАРОТИДНОМ СТЕНТИРОВАНИИ С АКЦЕНТОМ НА ДИАГНОСТИКУ МИКРОЭМБОЛИЧЕСКИХ ОЧАГОВ НА ДВ МРТ (TACTILE TRIAL)

Aim. To compare transradial (TR) and transfemoral (TF) approach for carotid artery stenting (CAS) with an emphasis on the detection of micro-embolization with diffusion-weighted magnetic resonance imaging (DW-MRI).Methods. 96 patients were included in the study in the period from January 2015 to October 2017 with further randomized 1 : 1 to the TR and TF groups. The inclusion criteria were the following: symptomatic stenosis ICA >70%; or asymptomatic stenosis ICA >80%. The positive history of stroke, myocardial infarction or open heart surgery <1 month were the exclusion criteria for the study. The primary endpoint was the incidence of new cerebral ischemic lesions as assessed by DW-MRI. All CAS procedures were performed by two experienced operators according to the approved protocol.Results. Procedural success with TR approach was 46 (96%) versus 48 (100%) with TF approach (p = 0.495). Crossover rate was 4% in the TR group. The rate of primary endpoint in the TR and TF groups was 50 and 52%, respectively. The absolute risk difference was -2% (95% CI [-0.21, 0.17], p (non-inferiority) = 0.03). An «on-treatment» analysis revealed a tendency towards a reduced microembolic foci when intervening on the right ICA via TR approach compared to TF (44% vs. 68%, p = 0.478), and a reverse trend when intervening on the left ICA via TR compared to TF approach (57% versus 36%, respectively, p = 0.437).Conclusion. Carotid stenting via transradial approach is noninferior for cerebral embolism to transfemoral approach. The rates of MACCE and vascular complications were similar in both groups. There was no significant difference in the procedural success rate in the transfemoral and transradial groups. The fluoroscopy time during transradial carotid stenting was higher in comparison with transfemoral carotid stenting, though the procedure duration was similar in both groups.Цель. Оценить эффективность и безопасность трансрадиального (ТР) и трансфеморального (ТФ) доступов при каротидном стентировании (КС) с акцентом на диагностику микроэмболических очагов на диффузионно-взвешенной магнитно-резонансной томографии (ДВ МРТ).Материалы и методы. С января 2015 г. по октябрь 2017 г. 96 пациентов были включены в исследование и рандомизированы 1:1 в группы КС ТР-доступом и КС ТФдоступом. Критериями включения в исследование были: симптомный стеноз внутренней сонной артерии (ВСА) >70% или асимптомный стеноз ВСА >80%. Наличие в анамнезе инсульта, инфаркта миокарда или открытой операции <1 месяца явились критерием исключения из исследования. Первичной конечной точкой была частота микроэмболических очагов, полученных на ДВ МРТ. Все процедуры КС были выполнены двумя опытными операторами.Результаты. В данном исследовании успех процедуры при ТР-доступе составил 46 (96%) против 48 (100%) при ТФ-доступе (p = 0,495). Частота перехода в другую группу (кроссовер) составила 4% в группе ТР. Частота достижения первичной конечной точки в группах ТР и ТФ составила 50 и 52% соответственно, разница абсолютных рисков составила -2% (доверительный интервал (ДИ) 95% [-0,21; 0,17]; p (non-inferiority) = 0,03). При «on-treatment» анализе наблюдалась тенденция к снижению микроэмболичских очагов при вмешательстве на правой ВСА через ТР-доступ, чем при ТФ (44% против 68%; p = 0,478), и обратная тенденция при вмешательстве на левой ВСА через ТР- и ТФ-доступами (57% против 36% соответственно; p = 0,437).Заключение. Трансрадиальный доступ при каротидном стентировании имеет не бо́льшую частоту возникновения микроэмболических поражений головного мозга, чем трансфеморальный. Не было получено достоверной разницы по частоте МАССЕ и сосудистых осложнений при каротидном стентировании трансрадиальным доступом по сравнению с трансфеморальным доступом. Частота успеха процедуры при трансрадиальном доступе по сравнению с трансфеморальным доступом достоверно не отличалась. Время флюроскопии при КС ТР-доступом выше, чем при ТФ-доступе, однако продолжительность процедуры в группах не отличалась

Синтез N-(4-бром-2-карбоксифенил)-глицина

Preparative methods of synthesis of N-(4-bromo-2-carboxyphenyl)-glycine and monopotassium salt of N-(2- carboxyphenyl)-glycine have been developеd.Осуществлена экспериментальная проверка методик синтеза монокалиевой соли N-(2-карбоксифенил)- глицина, при этом откорректирована методика ее получения на основе о-хлорбензойной кислоты и глицина. Отработаны условия бромирования монокалиевой соли N-(2-карбоксифенил)-глицина с целью получения N-(4-бром-2-карбоксифенил)-глицина. В результате разработаны препаративные методики получения моно- калиевой соли N-(2-карбоксифенил)-глицина и N-(4-бром-2-карбоксифенил)-глицина

Препаративный синтез N-ацетил-3-индолинонов

Compounds that contain an indole cycle in their structure have biological activity and are a source for the development of new medicinal products. N-acetyl-3-indolinones are actively used as incoming substance for their organic synthesis. Preparative methods for the obtaining of N-acetyl-3-indolinones, used as incoming substances for the synthesis of condensed indole derivatives with high therapeutic activity, have been developed. Synthesis of N-acetyl-3-indolinone was performed by deacetylation and cyclization of N-(2-carboxyphenyl) glycine and its 4-bromo-derivative to form N,O-diacetylindoxyls followed by hydrolysis of the obtained compounds to target indolinones. It was established that brominated derivatives have increased stability as compared with the analogues which do not contain bromine on the benzene ring of the indole nucleus, resulting in the increase in the yield of desired products in the reaction.Соединения, содержащие в своей структуре индольный цикл, обладают биологической активностью и являются источником для разработки новых лекарственных средств. Для их органического синтеза активно используются в качестве исходных веществ N-ацетил-3-индолиноны. Разработаны препаративные методики получения N-ацетил-3-индолинонов, применяемых в качестве исходных соединений для синтеза конденсированных производных индола, обладающих высокой терапевтической активностью. Синтез N-ацетил-3-индолинонов осуществляли путем диацетилирования и циклизации N-(2-карбоксифенил)глицина и его 4-бромпроизводного с образованием N,O-диацетилиндоксилов с последующим гидролизом полученных соединений до целевых индолинонов. Установлено, что бромзамещенные производные обладают повышенной стабильностью по сравнению с аналогами, не содержащими брома в бензольном кольце индольного ядра, в результате чего при их использовании в реакции повышается выход целевых продуктов