bluuebunny/crossref_metadata_2025 huggingface dataset:
The first experience of application of vessel endothelium growth factor inhibitor ranibizumab in complex therapy of retinopathy of premature in URFO in SAHI of the Sverdlovsk region MСMC «Bonum»
Authors:   State Autonomic health institution of the Sverdlovsk Region Multiprofile clinical medical center ", Kariakin M.A. ,   BONUM",   , Ural State children`s ophthalmological center, Ekaterinburg, Stepanova E.A. ,   State Autonomic health institution of the Sverdlovsk Region Multiprofile clinical medical center "BONUM", Ural State children`s ophthalmological center, Ekaterinburg,   FSBI HPE "Urals State Medical University " MOH Russia, Ekaterinburg, Korotkikh S.A. ,   State Autonomic health institution of the Sverdlovsk Region Multiprofile clinical medical center "BONUM", Ural State children`s ophthalmological center, Ekaterinburg,   FSBI HPE "Urals State Medical University " MOH Russia, Ekaterinburg, Timofeeva N.S. ,   State Autonomic health institution of the Sverdlovsk Region Multiprofile clinical medical center "BONUM", Ural State children`s ophthalmological center, Ekaterinburg, Surtaev S.I. ,   State Autonomic health institution of the Sverdlovsk Region Multiprofile clinical medical center "BONUM", Ural State children`s ophthalmological center, Ekaterinburg
Published: August 2021

Material and methods. The study included 16 patients (31 eyes). Types and terms of treatment. Stage I in the treatment of ROP, laser coagulation of the avascular areas of the retina was performed in three patients with aggressive posterior ROP (4 eyes, 12.9%). In all patients, the progression of the disease was noted. Intravitreal injection of ranibizumab was performed in the period from 8 to 16 weeks (10.5±2.0 weeks), PCV from 32.3 to 39.6 weeks (37.0±1.8 weeks). Result. After laser treatment and IVI of ranibizumab, 11 patients (31 eyes, 81.6%) showed regression of the disease. In 5 patients (6 eyes, 19.4%) - progression. If the ROP progressed, a 25G or 27G lenssparing vitrectomy was performed. Complete regression of ROP was achieved in one patient (1 eye, 16.7%). Partial regression was observed in two patients (2 eyes, 33.3%). In two patients (3 eyes, 50%), the disease progressed to stage 5 with the development of total retinal detachment. Conclusion. As a result of the complex treatment of severe forms of the active stage of retinopathy of prematurity in the regional children's ophthalmological center MKMC "Bonum" in Yekaterinburg, the following data were obtained: complete regression with retinal adhesion is observed in 12 patients (26 eyes, 83.4%), of which in one patient (1 eye, 3.2%) regression was achieved after vitrectomy. Partial regression with the formation of a peripheral retinal detachment after vitrectomy was achieved in two patients (two eyes - 6.5%). Progression of retinopathy of prematurity to stage V with the development of total retinal detachment in two patients (3 eyes, 9.6%). Complex treatment of severe stages of active ROP using laser treatment, IVI and vitrectomy allows to preserve vision in 90.4% of patients. Key words: retinopathy of prematurity; intravitreal injection; laser coagulation of the retina; vitrectomy.
Tactics and treatment results for uveal complications of laser coagulation with retinopathy of prematurity
Authors:   RAMS ", Kuznetsova Y.D. ,   Russian children's Clinical Hospital",   of Ministry of health of Russian Federation, Moscow, Russia, Astasheva I.B. ,   RAMS "Russian children's Clinical Hospital" of Ministry of health of Russian Federation, Moscow, Russia, Hatsenko I.E. ,   Russian national HBO GBOU research N.I. Pyrogov Medical University, Moscow, Russia, Zvereva A.N. ,   GBUZ Morozovskaya DGKB DZ Moscow, Gamayunova E.V. ,   RAMS "Russian children's Clinical Hospital" of Ministry of health of Russian Federation, Moscow, Russia
Published: August 2021

A pronounced inflammatory process from the anterior and posterior parts of the eye may occur, as a complications after laser coagulation in retinopathy of prematurity (ROP), in which there is a need for surgical treatment. Purpose. To determine the optimal tactics for the treatment of uveal complications of laser coagulation in ROP. Material and methods. For 2014-2020 we examined and performed surgical intervention in 21 children with uveal complications after laser coagulation (27 eyes), Most of the children were deeply premature (born at 24-26 weeks of gestation) with a birth weight of 500 g to 900 g with concomitant pathology from the central nervous system. Сomplicated cataracts developed for all children. All children underwent surgical treatment: reconstruction of the anterior chamber, microinvasive cataract extraction, vitrectomy (if necessary, schvartectomy). A single surgical intervention was performed on 24 eyes. In 3 eyes with a post-aggressive form of ROP and a history of sepsis, reoperative treatment was required. All children had no primary IOL implantation. IOL implantation was performed in one childe at an older age. Results. As a result of the treatment, in 89% of cases (24 eyes), there was a complete relief of the inflammatory process and restoration of the transparency of the media after a single surgical intervention. In childe who underwent secondary IOL implantation in the long term, there was a complicated course of early postoperative period and repeated reconstructive surgery required. Conclusions. Uveal complications after laser coagulation of the retina for ROP are observed mainly in children born in early gestation (24-26 weeks) with low birth weight (less than 1000 g). When carrying out the surgical treatment of uveal complications - cataract extraction, which has developed as a result of laser coagulation for ROP, vitrectomy is mandatory, and, if necessary, schwartectomy. When deciding on the secondary implantation of IOLs, it is necessary to take into account the high probability of an unfavorable course of the postoperative period in children with previous uveitis after laser treatment for retinopathy and prematurity. Key words: retinopathy of prematurity, uveal complications, cataract.
The role of intraocular f luid polymerase chain reaction in the diagnosis, treatment and monitoring of cytomegalovirus retinitis
Authors:   Dmitry Rogachev National Research Center of Hematology, Oncology and Immunology, Moscow, Pershin B.S. , Maschan A.A. ,   Dmitry Rogachev National Research Center of Hematology, Oncology and Immunology, Moscow, Makhmutov V.Y. ,   Endosurgery and litotrpsy Center, Moscow, Ilushina M.A. ,   Dmitry Rogachev National Research Center of Hematology, Oncology and Immunology, Moscow, Khismatullina R.D. ,   Dmitry Rogachev National Research Center of Hematology, Oncology and Immunology, Moscow
Published: August 2021

Purpose. To study the possibilities of a new method of CMRR treatment in the prevention of irreversible blindness. Material and methods. 74 patients with cytomegalovirus retinitis, frolicking after hematopoietic stem cell transplantation. The first group (9 people, 15 eyes) consisted of children, whose treatment was carried out under ophthalmoscopic control. The second group (65 people, 114 eyes) consisted of children in whom the control of the effectiveness of treatment was carried out using PCR of aqueous humor in real time. Results. In the first group, retinal detachment was diagnosed in three out of fifteen eyes, accounting for 20%. In the second group, the incidence of retinal detachment was 3.5% of 114 eyes. Among patients receiving treatment under ophthalmoscopic control, CMRR relapses were detected in 5 cases, which amounted to 33.3%. In children, whose treatment was controlled by intraocular fluid PCR, relapses were diagnosed in 22 cases, which amounted to 19.29%. Conclusions. Intravitreal administration of antiviral drugs under the control of polymerase chain reaction is a more effective method of treating cytomegalovirus retinitis than intravitreal administration under ophthalmoscopic control. Key words: cytomegalovirus retinitis, intraocular fluid polymerase chain reaction.
The use of protective red light filter glasses as a m ethod of preventing the development and progression of retinopathy of prematurity, based on the phenomenon of preconditioning photostimulation
Authors:   Regional Children's Clinical Hospital, Ushnikova O.A. , Epikhin A.N. ,   Rostov State Medical University, Ministry of Health of Russia, Epikhina Y.N. ,   Rostov State Medical University, Ministry of Health of Russia, Ushnikov A.N. ,   Regional Children's Clinical Hospital
Published: August 2021

Purpose. To study the possible effect of protective red light filter glasses as a method of preventing retinopathy of prematurity, based on the phenomenon of preconditioning photostimulation. Material and methods. For this study, we selected 20 children (40 eyes) from 26.5 to 36 weeks of gestational age and a birth weight of 650 to 2650 grams. All children were divided into 2 groups – the main and control groups of 10 children (20 eyes) each. Results. In the main group of the study, with the use of protective red light filter glasses, the best indicators of the electroretinogram were noted. Conclusions. The use of glasses with red protective light filters-as a method based on the phenomenon of preconditioning photostimulation, is a simple and affordable method of preventing retinopathy of prematurity, which reduces the need for surgical laser treatment and the number of adverse outcomes of this disease. Key words: retinopathy of prematurity, methods of prevention of retinopathy of prematurity.
System for diagnostics, monitoring and treatment of premature babies
Authors:   The S. Fyodorov Eye Microsurgery Federal State Institution, Novosibirsk Branch, Novosibirsk, Sharokhin M.A. , Mamulat D.R. ,   The S. Fyodorov Eye Microsurgery Federal State Institution, Novosibirsk Branch, Novosibirsk, Belousova K.A. ,   The S. Fyodorov Eye Microsurgery Federal State Institution, Novosibirsk Branch, Novosibirsk, Plisov I.L. ,   The S. Fyodorov Eye Microsurgery Federal State Institution, Novosibirsk Branch, Novosibirsk, Soloveva V.V. ,   The S. Fyodorov Eye Microsurgery Federal State Institution, Novosibirsk Branch, Novosibirsk
Published: August 2021

Purpose. Тo analyze of the effectiveness of the monitoring and treatment of premature babies. Material and methods. From 2012 to 2020 we observed 2113 preterm infants. Retinopathy of prematurity (ROP) was revealed in 731 cases (34.59%), 29 of them with aggressive posterior ROP (AP-ROP) (3.97%). 199 patients (27.22%) had indications for laser coagulation of the retina (LCR); repeated interventions were performed in 23 cases (11.56%). In 173 case (86.94%), an induced regression of the disease occurred. An unfavorable outcome of ROP was diagnosed in 26 cases (13.06%). 258 children with a cicatricial phase of ROP were dynamic observed. Results and conclusions. The effectiveness of LCR at the threshold stage has reached at 94.78%. Regression in type-I occurred in 89.09%. In cases of AP-ROP, the efficiency of LCR was 51.72%. The total number of children with terminal stages was 106 people (14.5%). In the cicatricial period of 258 people, 134 revealed ametropia, secondary glaucoma in 7 patients, complicated cataract in 6 and strabismus in 35. Timely diagnostics and monitoring reveals early signs of ROP and laser treatment. These activities minimize risk of disability from blindness and low vision. An insignificant number of LCR performed, a small number of patients with terminal stages of ROP indicates the high efficiency of modern conditions for nursing premature babies. Functional results depend on the degree of residual changes, refractive pathology and strabismus. Correction of ametropia, functional treatment, strabismus surgery in the preschool period, allow to develop and maintain visual function in the most of patients in the cicatricial phase of ROP. Key words: retinopathy of prematurity, laser coagulation of the retina, aggressive posterior retinopathy of prematurity.
Correlations between OCT and histological findings in choroidal melanomas
Authors:   Research Institute of Eye Diseases, Stoyukhina A.S. , Nechesnyuk S.U. ,   Moscow City Ophthalmological Center of S.P. Botkin City Clinical Hospital
Published: August 2021

It is known that OCT-detected retinal changes are comparable with histology resalts. Choroidal structure on EDI-OCT also comparable with histology. Purpose. To compare OCT-changes with pathomorphology in same microscopic sections. Material and methods. The analysis of OCT tomograms of 5 patients with choroidal melanomas (CM), who subsequently underwent primary enucleation. The patients age was 55,2±10,57 years. The maximum CM elevation is 4,85±1,76 mm, the maximum diameter is 13,09±4,14 mm. Results and discussion. The correlation of tomographic and histological picture was obtained in the following signs: signs of destruction of Bruch's membrane, the presence of hyperreflective changes at the RPE level, photoreceptors changes, the presence of neuroepithelial detachment, the presence of intraretinal cavities. Partial correlation - for signs of the presence of subretinal transudate and infiltration of the outer layers of the retina. No correlation was obtained for the signs of infiltration of the inner retina layers and the inner limitans membrane breakthrough with CM dissemination on a retinal surface. Conclusions. Comparison of OCT signs of MC with pathomorphological studies in 5 enucleated eyes made it possible to expand the interpretation of signs of CM spreading on OCT beyond the Bruch's membrane with the tumor growth zones formation in the retina. Key words: choroidal melanoma, optical coherence tomography of the retina, histological examination.
Clinical cases of rarely diagnosed forms of choroidal osteoma
Authors:   Republican specialized scientific and practical Medical center of the eye microsurgery, Yusupov A.F. , Akhmedova S.A. ,   Republican specialized scientific and practical Medical center of the eye microsurgery, Savranova T.N. ,   Republican specialized scientific and practical Medical center of the eye microsurgery, Rozukulov V.U. ,   Republican specialized scientific and practical Medical center of the eye microsurgery
Published: August 2021

Purpose. To analyze the 3 cases of choroidal osteomas, revealed in histological study after evisceration of eye. Material and methods. 3 patients (3 eyes) with chronic uveitis of different origin. Results. On histological examination, the bone tissue consisted of a network of bone beams of not fully mature type, with irregularly pronounced fibroreticular tissue between them. There was insignificant proliferation of endosteal cells in the fibroreticular component. There was marked interstitial edema, increased vascularization with hyperemia in the choroidal vascular plate. Conclusion. Preoperative diagnosis of choroidal osteomas is difficult because of the opacity of the eye media. Long term chronic uveitis of different origin was common to all given cases. Choroidal osteomas was an intraoperative finding and ossification process of choroid was indused by inflammatory process of the eye. Key words: choroidal osteomas, chronic uveitis.
Morphofunctional analysis of the retina in the surgical treatment of idiopathic macular holes
Authors:   S.N. Fedorov NMRC ", Zotov A.S. ,   MNTK ",   Eye Microsurgery",   , Volgograd Branch, Balalin A.S. ,   S.N. Fedorov NMRC "MNTK "Eye Microsurgery", Volgograd Branch, Balalin S.V. ,   S.N. Fedorov NMRC "MNTK "Eye Microsurgery", Volgograd Branch, Purshak S.M. ,   S.N. Fedorov NMRC "MNTK "Eye Microsurgery", Volgograd Branch, Melikhova I.A. ,   S.N. Fedorov NMRC "MNTK "Eye Microsurgery", Volgograd Branch, Marukhnenko A.M. ,   S.N. Fedorov NMRC "MNTK "Eye Microsurgery", Volgograd Branch, Efremova T.G. ,   S.N. Fedorov NMRC "MNTK "Eye Microsurgery", Volgograd Branch, Akhmedov A.E. ,   S.N. Fedorov NMRC "MNTK "Eye Microsurgery", Volgograd Branch
Published: August 2021

Purpose. To evaluate the role of microperimetry and optical coherence tomography (OCT) in the morphofunctional analysis of the retina after surgical treatment of idiopathic macular holes (IMH). Materials and methods. A retrospective study of 33 patient's treatment results (33 eyes) with IMH was carried out. All patients underwent minimally invasive with 25G or 27G vitrectomy. Best corrected visual acuity (BCVA), macular photosensitivity, fixation stability, macular neuroepithelial (NE) volume and minimal macular hole diameter were analyzed. Follow-up period: 6 months. Results. A complete closure of the macular hole was achieved in all cases post-op. The patients had reliable improvement of BCVA, retinal photosensitivity and decrease of macular NE volume. Based on a multifactor correlation analysis with the purpose to predict the results of surgical treatment, the dependence of post-op BCVA on the pre-op photosensitivity of the retina and the minimal diameter of the macular hole was revealed. Conclusions. Microperimetry and OCT are modern non-invasive research methods allowing to estimate anatomical and functional results of surgical IMH treatment. The study of retinal photosensitivity in the macula and minimal macular hole diameter pre-op allows to predict post-op BCVA, which has a practical importance. Keywords: idiopathic macular hole, vitrectomy, microperimetry, optical coherence tomography.
Treatment approach to patients with combined retinal diseases: wet form of age-related macular degeneration and epiretinal membrane. Preliminary results
Authors:   The S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Kolesnik S.V. , Zhuravlev A.S. ,   The S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Kolesnik A.I. ,   The S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Kakunina S.A. ,   The S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Norman K.S. ,   The S. Fyodorov Eye Microsurgery Federal State Institution, Moscow, Avakyan F.A. ,   The S. Fyodorov Eye Microsurgery Federal State Institution, Moscow
Published: August 2021

Introduction. Age-related macular degeneration (AMD) is one of the leading causes of irreversible vision loss among older patients. Since the introduction of anti-VEGF therapy, retinal specialists have been able to maintain or improve vision in patients with AMD. However, anti-VEGF therapy is ineffective in a certain percentage of patients. In 25-35% of cases of wet AMD, secondary epiretinal membranes (ERM) in the macular region are found. Anti-VEGF therapy has been found to be less effective in the treatment of wet AMD with ERM. Optimal treatment tactics for this combined pathology remains a matter of debate. Purpose. To evaluate the efficacy of different combined treatment approaches to patients with wet AMD and ERM. Methods. Study was performed on 2 eyes of 2 patients with ERM and AMD, wet form. Patients were divided in two groups. First patient received one loading dose of anti-VEGF drug (ranibizumab) and after that underwent standart pars plana vitrectomy (PPV) with removal of epiretinal and inner limiting membrane (ILM). Anti-VEGF therapy than was continued according to pro re nata regimen. Second patient underwent standart PPV with removal of ERM and ILM first. After the surgery, loading dose of anti-VEGF drug was injected. Anti-VEGF therapy than was continued according to pro re nata regimen. Results. After treatment, there was a decrease in central retinal thickness in both patients, but an increase in maximum corrected visual acuity was observed only in first patient. Conclusions. Based on the results of the performed study, the most optimal treatment approach to patients with wet AMD and ERM consisted of a single loading dose of anti-VEGF drug injection followed by PPV with removal of ERM and ILM and further continuation of anti-VEGF therapy for wet AMD. However, further research is needed to form a final conclusion about the effectiveness of the chosen treatment tactic. Key words: epiretinal fibrosis, AMD, CNVM, anti-VEGF
Changes of the level of pro- and anti-inflammatory cytokines in tear of patients with advanced proliferative diabetic retinopathy and complicated primary cataract depending on the volume vitreoretinal surgery
Authors:   N. Pirogov's National Medical Surgical Center, Moscow, Konovalova K.I. , Shishkin M.M. ,   N. Pirogov's National Medical Surgical Center, Moscow
Published: August 2021

Purpose. The aim is to estimate the content of pro- and anti-inflammatory cytokines (IL-1β, IL-8, IL-10, MCP-1, ICAM-1, VEGF) in tear of patients with advanced proliferative diabetic retinopathy and complicated primary cataract after phacoemulsification surgery and IOL implantation with vitreoretinal surgery accomplished at once in comparison with vitreoretinal surgery only. Material and methods. 34 cases of surgery treatment of patients with PDR and complicated primary cataract were enrolled. This patients were divided into two groups depending on the treatment tactics. In the 1st group patients were subjected to a two–step surgical procedure: vitreoretinal surgery (VRS) with silicone oil tamponade performed as the 1st step in their treatment; followed by the 2nd step, phacoemulsification surgery and silicone oil removal, and the IOL implantation, respectively. In the 2nd group phacoemulsification performed simultaneously with vitreoretinal surgery: phacoemulsification, IOL implantation, vitreoretinal surgery with silicone oil tamponade. The second step differed in the removal of silicone oil from the vitreous cavity. On the 2nd day after the 1st step surgery and before surgical treatment the tear samples of the patients of both groups have been examined. Results. A concentration of the following cytokines: IL-8, MCP-1, ICAM-1 in the 2nd group was 2,5-5 times higher than in the 1st group. Conclusion. The research revealed that the patients with advanced PDR are accurately determined by the increased concentration of IL-8, MCP-1, ICAM-1 in tear after phacoemulsification surgery and IOL implantation with vitreoretinal surgery accomplished at once in comparison with vitreoretinal surgery only. Keywords: cytokines, diabetic retinopathy, cataract, vitreoretinal surgery.
Analysis of the efficacy of endovitreal surgery with the internal limiting membrane removal in patients with X-linked congenital retinoschisis
Authors:   The S. Fyodorov Eye Microsurgery Federal State Institution, Tambov branch, Konyaev D.A.
Published: August 2021

Purpose of this article is to analyze the effectiveness of endovitreal surgery with removal of the internal limiting membrane in patients with X-linked congenital retinoschisis. Material and methods. Three male patients underwent a standard 25 G vitrectomy with staining and removal of the internal limiting membrane in the macular zone and pneumoretinopexy. Results. All operations were uneventful. Stabilization of the pathological process was noted during the study period. Conclusion. Endovitreal surgery with the removal of the inner limiting membrane in the macular zone stabilizes the progression of X-linked congenital retinoschisis. Key words: retinoschisis, internal limiting membrane, endovitreal surgery.
Subretinal proliferation. What to do?
Authors:   National Medical and Surgical Center named after N.I.Pirogov of the Ministry of Healthcare of the Russian Federation, Moscow, Krupina E.A. , Pavlovsky O.A. ,   National Medical and Surgical Center named after N.I.Pirogov of the Ministry of Healthcare of the Russian Federation, Moscow, Larina E.A. ,   National Medical and Surgical Center named after N.I.Pirogov of the Ministry of Healthcare of the Russian Federation, Moscow
Published: August 2021

Purpose. Evaluation of treatment results retinal detachment complicated by subretinal PVR. Materials and methods. We examined 13 patients (13 eyes) with operated retinal detachment (RD), subretinal proliferative vitreoretinopathy (PVR). In the main group (7 eyes) with recurrence of retinal detachment RD was complicated by severe subretinal proliferation. Аll the patients underwent surgical treatment of retinal detachment with removal of the subretinal PVR; in the control group (6 eyes) subretinal proliferation was localized in the zone of the adjacent retina and its removal was not performed. Results. The compared groups did not differ in terms of age and gender, the axis length of the eye. Duration of the RD was more than 3 months. During the observation period of 6 months of patients both groups, in all cases, it was possible to achieve a fit of the retina. Conclusion. 1. Subretinal PVR should be removed when it is localized in the macular area, or when it leads to retinal detachment, preventing it from fitting with standard technical manipulations. 2. Potential of microinvasive vitreoretinal surgery allow to effectively eliminate subretinal PVR, complementing standard manipulations, with a good functional and anatomical result. Keywords: retinal detachment, proliferative vitreoretinopathy, anatomical outcome.
Regularization of multilingual topic models
Authors: Дударенко М.А.
Published: August 2021

Предлагается многоязычная вероятностная тематическая модель, одновременно учитывающая двуязычный словарь и связи между документами параллельной или сравнимой коллекции. Для комбинирования этих двух видов информации применяется аддитивная регуляризация тематических моделей (ARTM). Предлагаются два способа использования двуязычного словаря: первый учитывает только сам факт связи между словами--переводами, во втором настраиваются вероятности переводов в каждой теме. Качество многоязычных моделей измеряется на задаче кросс-язычного поиска, когда запросом является документ на одном языке, а поиск производится среди документов другого языка. Показано, что комбинированный учет слов--переводов из двуязычного словаря и связанных документов улучшает качество кросс-язычного поиска по сравнению с моделями, использующими только один тип информации. Сравнение разных методов включения в модель двуязычных словарей показывает, что оценивание вероятностей переводов не только улучшает качество модели, но и позволяет находить тематический контекст для пар слово--перевод.

A multilingual probabilistic topic model based on the additive regularization ARTM allowing to combine both a parallel or comparable corpus and a bilingual translation dictionary is proposed. Two approaches to include information from a bilingual dictionary are discussed: the first one takes into account only the fact of connection between word translations, whereas the second one learns the translation probabilities for each topic. To measure the quality of the proposed multilingual topic model, a cross-language search is performed. For each query document in one language, it is found its translation on another language. It is shown that the combined translation of words from a bilingual dictionary and the corresponding connected documents improves the cross-lingual search compared to the models using only one information source. The use of learning word translation probabilities for bilingual dictionaries improves the quality of the model and allows one to determine a context (a set of topics) for each pair of word translations, where these translations are appropriate.
An algorithm for solving transient problems of gravitational gas dynamics: a combination of the SPH method with a grid method of gravitational potential computation
Authors: Стояновская О.П. , Снытников Н.В. , Снытников В.Н.
Published: August 2021

Для решения нестационарных уравнений гравитационной газовой динамики в приближении тонкого диска предложен новый численный алгоритм. Алгоритм основан на комбинации бессеточного метода сглаженных частиц (SPH, Smoothed Particle Hydrodynamics) и метода свeртки для решения уравнения Пуассона на декартовой сетке. Данный метод обладает высокой производительностью за счет того, что сеточная функция потенциала вычисляется и хранится только в плоскости диска. Работоспособность алгоритма демонстрируется в численных экспериментах по формированию структур в околозвездном диске. Сравнение результатов, полученных с использованием сеточных методов решения уравнения Пуассона в декартовой и цилиндрической геометрии, показало, что в обоих случаях удается воспроизвести решения с осевой симметрией и формирование уединенных областей повышенной плотности.

A new numerical algorithm to solve the unsteady equations of gravitational gas dynamics in the thin disk approximation is proposed. This algorithm is based on a combination of the meshless SPH (Smoothed Particle Hydrodynamics) method for
gas dynamics and the convolution method for solving Poisson's equation on a Cartesian grid. This convolution method is of high performance due to the fact that the grid potential function is computed and stored only in the plane of the disk. The efficiency of the algorithm is demonstrated by numerical experiments on the formation of structures in a circumstellar disk. We compare the results obtained by using the grid method for solving Poisson's equation in Cartesian and cylindrical geometry and show that in both these cases it is possible to reproduce the solutions with axial symmetry and to illustrate the formation of solitary regions of enhanced density.
Application of the boundary integral equation method to numerical solution of Dirichlet's boundary value problem in the elasticity theory on polygons
Authors: Арушанян И.О.
Published: August 2021

Рассматривается первая краевая задача плоской теории упругости в области с конечным числом угловых точек. Задаче ставится в соответствие система граничных интегральных уравнений теории потенциала. Исследуется вопрос об эффективном вычислении приближенного решения исходной краевой задачи на основе численного решения системы граничных интегральных уравнений.

Dirichlet's boundary value problem of the two-dimensional elasticity theory is considered for domains with a finite number of corner points. This problem is put in correspondence with a system of boundary integral equations used in the potential theory. An approach to the efficient approximate solution of the original boundary value problem by numerical solving the system of boundary integral equations is proposed.
Parallel forming of preconditioners based on the approximation of the Sherman-Morrison inversion formula
Authors: Новиков А.К. , Копысов C.П. , Недожогин Н.С.
Published: August 2021

Исследуются возможности ускорения предобусловленных методов бисопряженных градиентов (BiCGStab, Bi-Conjugate Gradient Stabilized) с предобусловливателем на основе аппроксимации обращения матрицы по формуле Шермана-Моррисона. Рассмотрена новая форма параллельного алгоритма, использующая матрично-векторные произведения при формирования матриц предобусловливателя. Показана эффективность распараллеливания наиболее ресурсоемких операций этого предобусловливателя на графических процессорах.

Acceleration of preconditioned bi-conjugate gradient stabilized (BiCGStab) methods with preconditioners based on the matrix approximation by the Sherman-Morrison inversion formula is studied. A new form of the parallel algorithm using matrix-vector products to generate preconditioning matrices is proposed. A parallelization efficiency of the most resource-intensive
operations of such preconditioners on multi-core central and graphics processing units (CPUs and GPUs) is shown.
Numerical simulation of the turbulence development at interaction of an electron beam with plasma
Authors: Берендеев Е.А. , Вшивков В.А. , Ефимова А.А. , Месяц Е.А.
Published: August 2021

Рассматривается задача взаимодействия электронного пучка с плазмой. Физический механизм взаимодействия плазмы с релятивистским электронным пучком включает в себя резонансное возбуждение колебаний плазмы, возникновение модуляции плотности плазмы и последующее рассеяние электронов на флуктуациях плотности. Для
моделирования использовался метод частиц-в-ячейках (PIC-метод). При решении задачи реализован параллельный алгоритм вычислений, расчеты проводились на различных суперЭВМ.

The interaction of an electron beam with plasma is considered. The physical mechanism of interaction between plasma and a relativistic electron beam includes a resonant excitation of plasma oscillations and the occurrence of plasma density modulation, followed by electron scattering. The numerical simulation is based on the particle-in-cell (PIC) method. A parallel algorithm is implemented to solve the problem under consideration. Two supercomputing systems were used to perform a number of numerical experiments.
On acceleration technologies of parallel decomposition methods
Authors: Гурьева Я.Л. , Ильин В.П.
Published: August 2021

Одним из главных препятствий масштабированному распараллеливанию алгебраических методов декомпозиции для решения сверхбольших разреженных систем линейных алгебраических уравнений (СЛАУ) является замедление скорости сходимости аддитивного итерационного алгоритма Шварца в подпространствах Крылова при увеличении количества подобластей. Целью настоящей статьи является сравнительный экспериментальный анализ различных приeмов ускорения итераций: параметризованное пересечение подобластей, использование специальных интерфейсных условий на границах смежных подобластей, а также применение грубосеточной коррекции (агрегации, или редукции) исходной СЛАУ для построения дополнительного предобусловливателя. Распараллеливание алгоритмов осуществляется на двух уровнях программными средствами для распределeнной и общей памяти. Тестовые СЛАУ получаются при помощи конечно-разностных аппроксимаций задачи Дирихле для
диффузионно-конвективного уравнения с различными значениями конвективных коэффициентов на последовательности сгущающихся сеток.

One of the main obstacles to the scalable parallelization of the algebraic decomposition methods for solving large sparse systems of linear algebraic equations consists in slowing the convergence rate of the additive iterative Schwarz algorithm in the Krylov subspaces when the number of subdomains increases. The aim of this paper is a comparative experimental analysis of various ways to accelerate the iterations: a parametrized intersection of subdomains, the usage of interface conditions at the boundaries of adjacent subdomains, and the application of a coarse grid correction (aggregation, or reduction) for the original linear system to build an additional preconditioner. The parallelization of algorithms is performed on two levels by programming tools for the distributed and shared memory. The benchmark linear systems under study are formed using the finite difference approximations of the Dirichlet problem for the diffusion-convection equation with various values of the convection coefficients and on a sequence of condensing grids.
A parallel optimization method for numerical solving the system of polaron equations using the partitioning algorithm
Authors: Волохова А.В. , Земляная Е.В. , Рихвицкий В.С.
Published: August 2021

Разработанный ранее метод численного моделирования процесса формирования поляронных состояний в конденсированных средах модифицирован с применением алгоритма разбиений, что обеспечивает существенное ускорение вычислений при расчетах в параллельном режиме на многопроцессорных системах. Программная реализация выполнена на основе технологии параллельного программирования MPI. Проведенные методические расчеты на Центральном информационно-вычислительном комплексе лаборатории информационных технологий Объединенного института ядерных исследований (Дубна) с различным количеством задействованных процессоров при выборе разных параметров вычислительной схемы подтверждают эффективность разработанного подхода для численного решения системы нелинейных дифференциальных уравнений в частных производных, описывающих динамическую модель полярона.

The previously developed method for the numerical simulation of the formation of polaron states in condensed media is modified using the partitioning algorithm, which provides a significant speedup in the parallel computations on multiprocessor
systems. The software implementation is based on the MPI technology. Numerical results obtained on the multiprocessor cluster installed at the Laboratory of Information Technologies (Joint Institute for Nuclear Research, Dubna) with various numbers of processors and with various computational parameters show that the proposed approach is efficient for the numerical solution of the system of nonlinear differential equations describing the polaron dynamical model.
Algorithms of optimal packing construction for planar compact sets
Authors: Казаков А.Л. , Лебедев П.Д.
Published: August 2021

Рассматривается задача об упаковке заданного числа равных кругов в компактное множество на плоскости при наибольшем возможном их радиусе. Разработан аналитический алгоритм отыскания наилучшей упаковки одного круга в многоугольник в евклидовом пространстве, основанный на максимизации функции расстояния от границы. На его основе создан алгоритм итерационного улучшения упаковки в выпуклое множество, использующий разбиение на подмножества (зоны Дирихле) с помощью диаграммы Вороного. Предложен численный алгоритм построения упаковки для случаев невыпуклого множества и неевклидовой метрики, основанный на оптико-геометрической аналогии. Проведено численное решение ряда примеров при большом количестве элементов упаковки в евклидовом пространстве и для одной специальной неевклидовой метрики.

The best packing problem for a prescribed number of equal disks in a compact planar set with their minimally possible radius is considered. An analytical algorithm for constructing the one disk best packing in a polygon in Euclidean space based on the maximization of the distance function from the boundary is proposed. An iteration algorithm based on the previous one is developed using the splitting into subsets (Dirichlet zones) with the aid of the Voronoi diagram. A numerical algorithm for packing in a nonconvex set in non-Euclidian metrics based on the optical geometric analogy is also proposed. A number of examples are numerically solved with a large number of packing elements and for a special non-Euclidian metrics.
Comparison of computational efficiency of explicit and implicit schemes for the sediment transport problem in coastal zones
Authors: Сухинов А.И. , Проценко Е.А. , Чистяков А.Е. , Шретер С.А.
Published: August 2021

Рассмотрена нестационарная пространственно-двумерная модель транспорта наносов в прибрежной зоне водоемов, учитывающая следующие физические параметры и процессы: пористость грунта; критическое значение касательного напряжения, при котором начинается перемещение наносов; турбулентный обмен; динамически
изменяемую геометрию дна и функцию возвышения уровня; ветровые течения; трение о дно. Построены и программно реализованы на кластере распределенных вычислений пространственно-трехмерная модель гидродинамики в прибрежной зоне водоемов и модель транспорта взвешенных частиц. Приведены результаты численных экспериментов.

An unsteady spatial two-dimensional sediment transport model in coastal zones is considered. The model takes into account the following physical parameters and processes: the soil porosity; the critical shear stress at which the sediment displacement begins; the turbulent exchange; the dynamically variable geometry of the bottom and the level elevation function; the wind flows; and the bottom friction. A spatial three-dimensional hydrodynamic model for coastal zones and a transport model for suspended particles are proposed and implemented on a computing cluster. Some numerical results are discussed.
A method of redundant constraint elimination in the problem of body recovery based on support function measurements
Authors: Палачев И.А.
Published: August 2021

Предложен новый алгоритм восстановления тел по измерениям их опорных функций, который представляет собой алгоритм квадратичного или линейного программирования в форме Гарднера-Кидерлена с меньшим числом ограничений. Уменьшение числа ограничений достигается за счет нового метода, который позволяет исключить из
исходной системы ограничений часть ограничений как избыточные. Предложен новый подход, позволяющий применять методы восстановления тел по измерениям опорной функции к задаче восстановления тел по теневым контурам. Представлено описание реализации алгоритма, а также результаты его тестирования на реальных
промышленных теневых контурах. Предложенный метод в рассмотренном примере позволил сократить число ограничений на 80% и ускорить исходный алгоритм Гарднера-Кидерлена на порядок.

A new body recovery algorithm based on support function measurements is proposed. The proposed algorithm represents a linear or quadratic programming problem in Gardner-Kiderlen form with smaller number of constraints. The reduction of constraint number is based on a new method that allows one to eliminate a part of initial constraints as redundant. A new approach of body recovery based on shadow contours is proposed. It allows one to reuse body recovery methods based on support function measurements. The implementation of the algorithm is described and some results of its testing on real industrial contours are discussed. The proposed method ensures the reduction of constraint number by 80% in the discussed example and also enables to speedup the initial Gardner-Kiderlen algorithm by an order of magnitude.
A parallel implementation of a fast method for solving the Smoluchowski-type kinetic equations of aggregation and fragmentation processes
Authors: Матвеев С.А.
Published: August 2021

Предложена параллельная реализация быстрого алгоритма решения систем кинетических уравнений агрегации и фрагментации типа уравнений Смолуховского. Эффективность реализации продемонстрирована на конкретных задачах агрегационно-фрагментационной кинетики. С помощью предложенной параллельной реализации быстрого алгоритма получены решения с осциллирующей полной плотностью агрегатов.

A parallel implementation of a fast algorithm for solving systems of the Smoluchowski-type kinetic equations of aggregation and fragmentation processes is proposed. The efficiency and scalability of the proposed implementation are shown for several particular problems of aggregation and fragmentation kinetics. The oscillatory solutions of the Cauchy problems are found using the developed parallel algorithm in terms of total density.
Modeling of riveted assembly of wing sheathing with forward stiffeners
Authors: Бормотин К.С. , Олейников А.И. , Овчаров И.О.
Published: August 2021

Проводится моделирование процесса высокоресурсного заклепочного соединения элемента панели двойной кривизны с ребрами жесткости. Приводится математическая постановка задачи клепки швов панели и ребер жесткости. Предложен итерационный метод определения упреждающих кривизн ребер, которые обеспечивают заданные геометрические параметры клепаных панелей. Предлагается реализация метода в комплексе программ конечно-элементного анализа MSC.Marc и MSC.Patran.

Modeling of a high-reliability riveted joint of a double-curvature panel with ribbed stiffeners is considered. A mathematical formulation of the problem devoted to riveting the joints of panels and stiffeners is given. An iterative method of determining the forward curvatures of stiffeners that provide the prescribed geometrical parameters of riveted panels is proposed. This method is implemented using the MSC.Marc and MSC.Patran finite-element analysis software packages.
Flow visualization with strong and weak gas dynamic discontinuities in computational fluid dynamics
Authors: Булат П.В. , Волков К.Н. , Яковчук М.С.
Published: August 2021

Рассматриваются методы визуализации течений с газодинамическими разрывами, позволяющие проводить сравнение результатов численного моделирования с данными физического эксперимента. Дается обзор методов оптической визуализации течений сжимаемого газа (теневые картины, шлирен-изображения, интерферограммы).
Приводятся примеры визуального представления решений ряда задач газовой динамики, связанных с расчетами течений, содержащих слабые и сильные газодинамические разрывы. Для повышения наглядности результирующего
образа применяются топологические методы визуализации, позволяющие определить положение критических точек, линий отрыва и присоединения потока.

A number of methods for the visualization of flows with gas dynamic discontinuities are considered. These methods allow one to perform the direct comparison of numerical results with experimental data. Methods for the optical visualization of compressible gas flows (shadowgraphs, schlieren images, and interferograms) are discussed. Some examples illustrating the
visual representation of numerical solutions of gas dynamics problems related to flows containing weak and strong gas dynamic discontinuities are given. Topological methods of visualization are applied to increase the visual representation of resulting images and to define the locations of critical points as well as the separation and attachment lines.
Mathematical modeling of inverse multipoint forming problems in the creep mode using a reconfigurable tool
Authors: Бормотин К.С. , Белых С.В. , Вин А.
Published: August 2021

Математическая формулировка обратных задач формообразования в режиме ползучести на реконфигурируемой штыревой машине основана на построении функционалов прямых и обратных экстремальных квазистатических задач формообразования деталей с учетом контактных условий с оснасткой. Построен итерационный метод расчета перемещений стержней матриц формблока, обеспечивающих заданную остаточную кривизну панели. Численные решения задач достигаются методом конечных элементов в системе MSC.Marc. Показана сходимость метода на примере формообразования панели.

A mathematical formulation of inverse forming problems in the creep mode using a reconfigurable tool is based on the creation of functionals for the direct and inverse extreme quasistatic problems of forming details with consideration of contact conditions with equipment. An iterative method of determining the displacements of pins of the tool's matrices providing
a given residual curvature of the panel is proposed. The problems are numerically solved by a finite element method in the framework of the MSC.Marc system. The convergence of the proposed iterative method is shown by an example of panel shaping.
2D and 3D algorithms of introcontinuation
Authors: Гласко Ю.В.
Published: August 2021

Рассматривается задача интропродолжения поля с целью локализации источников его аномалий. Предложены математическая модель поля (сводящаяся к задаче Дирихле, в которой в качестве границы области выступает дневная поверхность), а так же новые 2D- и 3D-алгоритмы решения указанной задачи. Алгоритмы локализации особых точек продолженного в нижнюю полуплоскость поля базируются на расчете конечно-разностных аппроксимаций полного нормированного градиента В.М. Березкина (КПНГ). Разработаны два конечно-разностных
варианта интропродолжения, сокращающих (в сравнении с рядами Фурье) количество необходимой для работы алгоритма априорной информации. Представлен модельный пример работы методики в площадном (3D) варианте, позволяющий локализовать объекты по наблюденному гравитационному полю.

The introcontinuation of a potential field for the localization of sources in the field's anomalies is discussed. A mathematical model of the field is proposed on the basis of the Dirichlet problem with a condition on the day surface. New 2D and 3D algorithms are developed to determine the critical points for the field continued into the lower half-plane. These algorithms are based on a finite-difference approximation of Berezkin's complete normalized gradient and on the determination of its critical points. Two versions of the finite-difference introcontinuation reduce a priori information requiring for the algorithms. A model experiment for the areal version (3D) procedure is considered to illustrate the determination of objects by the observed gravity field.