83 research outputs found
Fluctuation-induced local oscillations and fractal patterns in the Lattice Limit Cycle model
No full textThe fractal properties of the Lattice Limit Cycle model are explored when the process is realized on a 2-dimensional square lattice support via Monte Carlo Simulations. It is shown that the structure of the steady state presents inhomogeneous fluctuations in the form of domains of identical particles. The various domains compete with one another via their borders which have self-similar, fractal structure. The fractality is more prominent, (fractal dimensions d(f) < 2), when the parameter values are near the critical point where the Hopf bifurcation occurs. As the distance from the Hopf bifurcation increases in the parameter space the system becomes more homogeneous and the fractal dimension tends to the value d(f) = 2
Sorption of calcium ions by modified montmorillonite
No full textModified sorbents based on montmorillonite hydrosols were obtained. Sorption of calcium from various solutions was studied. The effect of pH and concentration of an alkaline agent on calcium sorption was determined. As opposed to using NaOH as the alkaline agent, the use of Na2CO3 resulted in formation of less stable colloidal particles in the solution and, therefore, the process of calcium separation occurred more intensively. Sorption of calcium ions increased with the increasing pH value and dosage of the montmorillonite hydrosol. Thus, the modified montmorillonite can be used for separation of calcium ions from aqueous solutions with simultaneous elimination of a suspended matter. © 2019 Author(s)
Adsorption-coagulation separation of cesium and strontium ions by intercalated aluminosilicates
No full textAdsorption and coagulation properties of intercalated montmorillonites were studied in aqueous systems containing cesium and strontium ions. It was shown that cesium sorption results in formation of two monomolecular layers of this component on the surface of the montmorillonite. Adsorption of strontium occurs due to formation of monolayer in pores of the mineral. Besides adsorption, coagulation of the sorbent's particles was intensified. Slow mixing of the solution resulted in particles aggregation, formation of large aggregates and their sedimentation. It was shown that particles aggregation occurred due to decrease of the charge as a result of ions adsorption. Rate constants of the solid phase coagulation were calculated. It was determined for ions with equal electric charges that coagulating ability of the ion increased with the decrease of the radius of hydrated ion. © 2019 Author(s)
Treatment of splenic artery aneurysms of patients with cirrhosis in the Waiting list
Get PDFObjective. The aim of our work was to evaluate the immediate and remote results of ligation of splenic artery aneurysm in orthotopic liver transplantation in patients with decompensated liver cirrhosis.Material and methods. From June 2018 to May 2024, 232 liver transplants from a posthumous donor were performed at the Surgical Clinic of the Moscow Multidisciplinary Scientific and Clinical Center n.a. S.P. Botkin. In 4 patients (1.7%), the presence of aneurysmal dilatation of the splenic artery was revealed at the preoperative stage. During orthotopic liver transplantation, patients underwent ligation of the splenic artery proximal and distal to the aneurysms.Results. Mean time for the isolation and ligation of the splenic artery aneurysm was 18.4±3.3 minutes. In no case was there any damage or bleeding from either the branches or the aneurysm of the splenic artery; and there was no damage to the spleen. No adverse events related to the splenic artery aneurysm ligation were recorded in either early or late postoperative periods. In all cases, the control examination did not reveal any ischemic changes in the splenic parenchyma.Conclusion. Ligation of the splenic artery aneurysm during orthotopic liver transplantation is a safe, effective and necessary surgical intervention that can improve long-term results by reducing the risk of death from aneurysm rupture in the postoperative period
An absolute calibration site for radar altimeters in the continental domain : lake Issykkul in Central Asia
No full textAltimetry missions such as Topex/Poseidon, Jason-1, GFO and ENVISAT have been widely used in the continental domain over lakes, rivers and wetland although they were mostly dedicated to oceanic studies. Knowledge of the instrumental biases is a key issue. Numerous sites have been dedicated to calibration purposes, either in the oceanic domain (Harvest offshore platform in California, Corsica, Bass Strait in Australia) or over lakes (Lake Erie in United States). A new site (Lake Issykkul in Kirghizstan) is proposed for calibration in the continental domain. This lake is covered by past (T/P) and current radar altimetry satellites (Jason-1, T/P, GFO, and ENVISAT). Several in situ water levels and local meteorological variables are available at the site. Located in a mountainous area, it offers an opportunity for calibration far away from all other existing sites and very different environment contexts. Two GPS campaigns have been conducted on the lake in 2004 and in 2005. They consisted of cruises with stations installed onboard a boat following the satellite ground tracks, and onshore settings. This enabled estimating a bias for each altimeter and each tracking algorithm available. Biases obtained for Envisat, GFO, T/P and Jason-1 using the default ocean tracker (respectively, 48.1 +/- 6.6, 7.5 +/- 4.0, 0 +/- 4.3 and 7.0 +/- 5.5 cm) agree with biases published at the other calibration sites. For Jason-1, there is a significant disagreement with results obtained in the ocean field (7 cm instead of 13 cm) but is coherent with bias obtained on the Lake Erie site. Erroneous estimates of the sea state bias correction from non-oceanic-like waveforms is discussed as a possible explanation. Errors in the ionospheric, wet and dry tropospheric corrections for the continental domain are also highlighted and quantified
Impulsive practical synchronization of n-dimensional nonautonomous systems with parameter mismatch
Get PDFsummary:This paper is concerned with impulsive practical synchronization in a class of n-dimensional nonautonomous dynamical systems with parameter mismatch. Some simple yet general algebraic synchronization criteria are derived based on the developed practical stability theory on impulsive dynamical systems. A distinctive feature of this work is that the impulsive control strategy is used to make n-dimensional nonautonomous dynamical systems with parameter mismatch achieve practical synchronization, where the parameter mismatch likewise exist in both system parameters and external excitation ones, and the synchronization error bound can be estimated by an analytical expression. Subsequently, the obtained results are applied to a typical gyrostat system, and numerical simulations demonstrate the effectiveness of the criteria and the robustness of the control technique
Анализ антенны вытекающей волны на основе частично заполненного прямоугольного волновода
Get PDFA leaky-wave antenna based on the partially-filled rectangular waveguide with transverse slots is investigated. Using tensor Green’s functions for antenna radiation analysis is suggested. A transcendental equation for a complex wavenumber obtained by matching magnetic fields inside and outside the waveguide is presented. Plots of velocity factor dependencies on waveguide filling parameters are shown. An influence of dielectric layer position on the antenna performances is investigated. Radiation pattern is estimated.Исследована антенна вытекающей волны на основе частично заполненного диэлектриком прямоугольного волновода с поперечными щелями. Предложено применение тензорных функций Грина для анализа излучения антенны. Приведено трансцендентное уравнение для определения комплексной постоянной распространения волны, полученное сопоставлением магнитного поля внутри и снаружи щели. Представлены зависимости коэффициента замедления от параметров заполнения волновода диэлектриком. Исследовано влияние положения диэлектрика внутри волновода на характеристики антенны. Проанализирована диаграмма направленности антенны
The Immune Landscape of Cancer (Immunity (2018) 48 (812–832), (S1074-7613(18)30121-3), (10.1016/j.immuni.2018.03.023))
No full text(Immunity 48, 812–830.e1–e14; April 17, 2018) In the originally published version of this article, the authors neglected to include Younes Mokrab and Aaron M. Newman as co-authors and misspelled the names of authors Charles S. Rabkin and Ilya Shmulevich. The author names have been corrected here and online. In addition, the concluding sentence of the subsection “Immune Signature Compilation” in the Method Details in the original published article was deemed unclear because it did not specify differences among the gene set scoring methods. The concluding sentences now reads “Gene sets from Bindea et al., Senbabaoglu et al., and the MSigDB C7 collection were scored using single-sample gene set enrichment (ssGSEA) analysis (Barbie et al., 2009), as implemented in the GSVA R package (Hänzelmann et al., 2013). All other signatures were scored using methods found in the associated citations.
Morphological justification of organ-preserving methods of surgical treatment of patients with liver echinococcosis
Get PDFThe purpose of the research is the study of the morphological structure of echinococcal cysts to assess the possibility of using organ-preserving methods of surgical treatment.Materials and methods. A clinical, instrumental, and morphological fundamental study was performed in the Surgical Clinic of the Botkin Hospital when radiation and morphological data in addition to clinical data were studied for 28 patients who underwent surgical treatment for liver echinococcosis. Excised gross specimens were examined to study the capsule structure, and the penetration of germinal elements of the cysts through membranes of the parasite (64 successively excised primary operated echinococcal cysts).Results and discussion. The fibrous capsule of the echinococcal cyst is a good barrier against Protoscolexes penetrating into the liver tissue. None of the 64 specimens studied in detail was found to have germinal elements of any echinococcal cyst penetrating through its fibrous capsule. The morphological justification of organ-preserving methods in the treatment of patients with liver echinococcosis allows a conclusion that these interventions are safe and radical
КОМБИНИРОВАННОЕ ЛЕЧЕНИЕ БОЛЬНЫХ НЕОПЕРАБЕЛЬНЫМИ МЕТАСТАЗАМИ КОЛОРЕКТАЛЬНОГО РАКА ПЕЧЕНИ
Get PDFThe purpose of the study was to improve treatment outcomes for patients with inoperable colorectal liver metastases using the combination of chemoembilization of the hepatic artery and radiofrequency ablation.Material and methods. Treatment outcomes of 60 patients with methachronic unresectable liver metastases from colorectal cancer were analyzed. Eligibility criteria were as follows: absence of extrahepatic metastases, size of metastases from 3 to 5 cm, and inability to perform resection. All patients were divided into two groups. Group I included 30 patients who received combination of regional chemotherapy and radiofrequency ablation. Group II (the control group) consisted of 30 patients who received radiofrequency ablation only.Results. Post-embolization and post-ablation syndromes were observed in both groups of patients. Rightsided hydrothorax (Clavien-Dindo grade II) was found in 4 out of 60 patients (2 patients in Group I and 2 patients in Group II). One-, two- and three-year disease-free survival rates in Group I patients were 96.6 %, 76.6 % and 53.3 %, respectively. The corresponding rates in the control group patients were 90.0 %, 53.6 % and 30.0 %, respectively (p=0.049). The overall one-, two-and three-year survival rates in Group I patients were 100 %, 90 % and 63.3 %, respectively. The corresponding rates in the control group patients were 100 %, 70 % and 50.0 %, respectively (p=0.202).Conclusion. The combination of regional chemotherapy and radiofrequency ablation led to the improvement in overall and disease-free survival rates.Цель исследования – улучшить результаты лечения больных с нерезектабельными метастазами колоректального рака печени путем комбинации химиоэмболизации печеночной артерии и радиочастотной аблации.Материал и методы. Проанализированы результаты лечения 60 больных с метахронныминерезектабельными метастазами колоректального рака в печень. Критерии включения: отсутствие экстрапеченочных метастазов; размер метастазов от 3 до 5 см; невозможность проведения резекционного вмешательства. Больные были разделены на основную группу (30 пациентов), куда вошли те, кому проведена комбинация регионарной химиотерапии и радиочастотной аблации, и контрольную группу (30 пациентов), в нее вошли больные, которым проведена радиочастотная аблация.Результаты. Постэмболизационный и постаблационный синдром был у всех больных основной и контрольной групп. Осложнения были у 4 из 60 больных (2 больных в основной группе и 2 больных в контрольной группе (p=1)) – правосторонний гидроторакс (II класс по Clavien-Dindo). Безрецидивная выживаемость в основной группе за первый год составила 96,6 %, за второй – 76,6 %, за третий – 53,3 %. В контрольной группе – 90,0, 53,6 и 30,0 % соответственно (p=0,049). Общая одно-, двух- и трехлетняя выживаемость у больных основной группы составила 100, 90 и 63,3 %. В контрольной группе – 100, 70 и 50,0 % соответственно (p=0,202).Заключение. Применение на практике комбинированного метода позволило улучшить результаты лечения больных с нерезектабельными метастазами колоректального рака печени за счет увеличения общей и безрецидивной выживаемости
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