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  1. Book ; Online: TreeDQN

    Sorokin, Dmitry / Kostin, Alexander

    Learning to minimize Branch-and-Bound tree

    2023  

    Abstract: Combinatorial optimization problems require an exhaustive search to find the optimal solution. A convenient approach to solving combinatorial optimization tasks in the form of Mixed Integer Linear Programs is Branch-and-Bound. Branch-and-Bound solver ... ...

    Abstract Combinatorial optimization problems require an exhaustive search to find the optimal solution. A convenient approach to solving combinatorial optimization tasks in the form of Mixed Integer Linear Programs is Branch-and-Bound. Branch-and-Bound solver splits a task into two parts dividing the domain of an integer variable, then it solves them recursively, producing a tree of nested sub-tasks. The efficiency of the solver depends on the branchning heuristic used to select a variable for splitting. In the present work, we propose a reinforcement learning method that can efficiently learn the branching heuristic. We view the variable selection task as a tree Markov Decision Process, prove that the Bellman operator adapted for the tree Markov Decision Process is contracting in mean, and propose a modified learning objective for the reinforcement learning agent. Our agent requires less training data and produces smaller trees compared to previous reinforcement learning methods.

    Comment: Submitted to NeurIPS 2023
    Keywords Computer Science - Machine Learning ; Mathematics - Optimization and Control
    Subject code 006
    Publishing date 2023-06-09
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Transformational features of the vein wall during a long-term period of endovenous laser ablation using 1910 nm laser radiation. Results of in-vivo experiments.

    Artemov, Sergey A / Belyaev, Alexander N / Bushukina, Olga S / Davydkin, Vasiliy I / Khrushchalina, Svetlana A / Kostin, Sergey V / Ryabochkina, Polina A / Taratynova, Alina D

    International angiology : a journal of the International Union of Angiology

    2023  Volume 42, Issue 4, Page(s) 362–370

    Abstract: Background: In this paper, results of in-vivo experiments on the animals of endovenous laser ablation (EVLA) using laser radiation with the wavelength 1910 nm are reported. The results of histological studies of the vein segments removed immediately ... ...

    Abstract Background: In this paper, results of in-vivo experiments on the animals of endovenous laser ablation (EVLA) using laser radiation with the wavelength 1910 nm are reported. The results of histological studies of the vein segments removed immediately after the procedure and in a long-term period (30 days and 3 months) are presented. Their structural transformation and the obliteration degree of the vein lumen using different values of the linear energy density of laser radiation (LEED=7.5; 15; 20 J/cm) are estimated.
    Methods: Edilbay breed of sheep (males) were used as experimental animals. Laser radiation with a wavelength of λ=1910 nm and power of Р<inf>rad</inf> = 1.5, 3, 4 W was used for EVLA experiments, and speed of fiber traction (v) was 2 mm/s. 8 days after EVLA stitches and an elastic bandage were removed. Animals were observed for 3 months in the vivarium. Animals have duplex ultrasound scanning of coagulation veins under anesthesia, after analysis vein segments were excised for histological examination. As a result, the damage degree to the vein wall tissues (intima, media, adventitia) and peri-venous tissues was revealed.
    Results: It is shown that in the long-time period, the intima and partial muscle layer transformed to connective tissue. EVLA using laser radiation with a higher value of LEED led to the growth of connective tissue, oedema of all vein layers and peri-venous tissue. The lumen closure occurred due to clot and the vein wall transformation, a maximum value was 25% using LEED=20 J/cm.
    Conclusions: The connective-tissue transformation of the coagulated vein occurs in a long-term period and more pronounced for higher LEED. However, features of vein hemodynamics of animals and differences between the clot formation process of human varicose veins and healthy animal veins lead to incomplete occlusion. These features should be taken into account during extrapolation results of experiments on animals in clinical practice.
    Language English
    Publishing date 2023-07-20
    Publishing country Italy
    Document type Journal Article
    ZDB-ID 604910-2
    ISSN 1827-1839 ; 0392-9590
    ISSN (online) 1827-1839
    ISSN 0392-9590
    DOI 10.23736/S0392-9590.23.05013-7
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Book ; Online: Time Optimization of Constrained Control for a Thermoelectric Solid System with a Peltier Element

    Gavrikov, Alexander / Kostin, Georgy

    2022  

    Abstract: A solid system consisting of two heat conducting cylinders with a thermoelectric converter (Peltier element) between them is considered. A nonlinear model, which was previously verified by authors, is used to design a constrained control law that allows ... ...

    Abstract A solid system consisting of two heat conducting cylinders with a thermoelectric converter (Peltier element) between them is considered. A nonlinear model, which was previously verified by authors, is used to design a constrained control law that allows us to achieve a steady-state distribution of the temperature in one of the cylinders in much less time than the characteristic time of transient processes. The initial-boundary value problem is exactly linearized over temperature by means of feedback linearization. Although the resulting system is nonlinear in a control function, it is possible to construct a finite-dimensional approximation based on analytical solution of the corresponding eigenproblem for a constant control signal. The time-optimal control problem is studied numerically by using this eigenfunction decomposition. To construct admissible control laws, an auxiliary unconstrained optimization problem is introduced. Its cost functional represents a weighted sum of temperature deviation from the desired zero distribution and a penalty for violating an electric power constraint. The control time interval is split into several parts, and on each subinterval the control signal is taken constant. The optimal piecewise constant feedforward control is found numerically by applying the gradient descent method. We analyze the proposed control law with respect to the shortest admissible time of the process.
    Keywords Electrical Engineering and Systems Science - Systems and Control ; Condensed Matter - Materials Science ; 80M50 (Primary) 80M22 ; 49M41 (Secondary)
    Subject code 531
    Publishing date 2022-06-14
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article: Rhodium-Based Catalysts: An Impact of the Support Nature on the Catalytic Cyclohexane Ring Opening.

    Kartavova, Kristina E / Mashkin, Mikhail Yu / Kostin, Mikhail Yu / Finashina, Elena D / Kalmykov, Konstantin B / Kapustin, Gennady I / Pribytkov, Petr V / Tkachenko, Olga P / Mishin, Igor V / Kustov, Leonid M / Kustov, Alexander L

    Nanomaterials (Basel, Switzerland)

    2023  Volume 13, Issue 5

    Abstract: Because of the growing demand for high-quality fuels, the light cycle oil fraction improvement including cetane number improvement is important. The main way to reach this improvement is the ring opening of cyclic hydrocarbons, and a highly effective ... ...

    Abstract Because of the growing demand for high-quality fuels, the light cycle oil fraction improvement including cetane number improvement is important. The main way to reach this improvement is the ring opening of cyclic hydrocarbons, and a highly effective catalyst should be found. Cyclohexane ring openings are a possible option to investigate the catalyst activity. In this work, we investigated rhodium-loaded catalysts prepared using the commercially available industrial supports: single-component ones, SiO
    Language English
    Publishing date 2023-03-04
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662255-5
    ISSN 2079-4991
    ISSN 2079-4991
    DOI 10.3390/nano13050936
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Does Background Matter? A Comparative Characterization of Mouse Models of Autosomal Retinitis Pigmentosa rd1 and Pde6b-KO.

    Chirinskaite, Angelina V / Rotov, Alexander Yu / Ermolaeva, Mariia E / Tkachenko, Lyubov A / Vaganova, Anastasia N / Danilov, Lavrentii G / Fedoseeva, Ksenia N / Kostin, Nicolay A / Sopova, Julia V / Firsov, Michael L / Leonova, Elena I

    International journal of molecular sciences

    2023  Volume 24, Issue 24

    Abstract: Many retinal degenerative diseases result in vision impairment or permanent blindness due to photoreceptor loss or dysfunction. It has been observed that ... ...

    Abstract Many retinal degenerative diseases result in vision impairment or permanent blindness due to photoreceptor loss or dysfunction. It has been observed that Pde6b
    MeSH term(s) Humans ; Mice ; Animals ; Retinal Degeneration/pathology ; Electroretinography ; Mice, Inbred C3H ; Retinitis Pigmentosa/pathology ; Retina/pathology ; Disease Models, Animal
    Language English
    Publishing date 2023-12-06
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2019364-6
    ISSN 1422-0067 ; 1422-0067 ; 1661-6596
    ISSN (online) 1422-0067
    ISSN 1422-0067 ; 1661-6596
    DOI 10.3390/ijms242417180
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Theoretical prerequisites for substantiating the parameters of a rotary ripper for interrow potato cultivation

    Pervushin Vladimir / Salimzyanov Marat / Ivanov Alexey / Kostin Alexander / Shklyaev Konstantin

    E3S Web of Conferences, Vol 380, p

    2023  Volume 01003

    Abstract: The article is devoted to the study of the process of interaction of the rotary ripper’s working bodies with the soil. The classification of rotary machines and implements according to the energy transmitted to the working body and the location of the ... ...

    Abstract The article is devoted to the study of the process of interaction of the rotary ripper’s working bodies with the soil. The classification of rotary machines and implements according to the energy transmitted to the working body and the location of the rotation axis is outlined. The article notes that the main characteristics of the rotor work body motion are the trajectory type, the magnitude and direction of velocity of its most characteristic point, and in some cases, the magnitude and direction of acceleration. The article presents the results of theoretical research in the field of kinematics of interaction of rotary working tools with the soil. The design of the rotary ripper is presented and the description of the trajectory of its working bodies is made, the value of movement of the scraper plate in the contact area with the soil is established. We analyzed the segment of the path from the beginning of contact with the soil (the beginning of dragging the surface layer of soil) and the end of contact (the end of dragging the surface layer of soil), on the line of which weed combing, loosening and destruction of soil crust occurs.
    Keywords Environmental sciences ; GE1-350
    Subject code 630
    Language English
    Publishing date 2023-01-01T00:00:00Z
    Publisher EDP Sciences
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Data on physico-chemical characteristics and elemental composition of gray forest soils (Greyzemic Phaeozems) in natural-technogenic landscapes of Moscow brown coal basin.

    Kostin, Alexander S / Krechetov, Pavel P / Chernitsova, Olga V / Terskaya, Elena V

    Data in brief

    2021  Volume 35, Page(s) 106817

    Abstract: Waste rocks material and acid mine drainage (AMD) in sulfur coal mining areas of Moscow brown coal basin lead to significant transformation of landscape components (soils, surface, and groundwaters). Most of the abandoned sulfide-bearing spoil heaps have ...

    Abstract Waste rocks material and acid mine drainage (AMD) in sulfur coal mining areas of Moscow brown coal basin lead to significant transformation of landscape components (soils, surface, and groundwaters). Most of the abandoned sulfide-bearing spoil heaps have not been reclaimed and toxic products of their weathering cause the risk of long-term soil contamination. In this article, we report original data on some physico-chemical properties and elemental composition of liquid and solid soil phases, waste dumps and AMD from twо abandoned spoil heaps of the Moscow basin and adjacent territories (the Tula region, Central Russia). Soil samples were collected from each genetic horizon of soil depth profile at sites affected by waste dumps and mine subsidence, as well as at natural sites. Waste material was sampled from the different parts of the spoil heaps. Sampling of AMD was performed in technogenic reservoirs near waste dumps. In displaced liquid phases (by ethanol) from soils and waste dump material, natural superficial waters and AMD pH-value, electrical conductivity (EC), the content and composition of readily soluble salts (by high-performance liquid chromatography (HPLC)), as well as titratable acidity (H
    Language English
    Publishing date 2021-01-30
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2786545-9
    ISSN 2352-3409 ; 2352-3409
    ISSN (online) 2352-3409
    ISSN 2352-3409
    DOI 10.1016/j.dib.2021.106817
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Rhodium-Based Catalysts

    Kristina E. Kartavova / Mikhail Yu. Mashkin / Mikhail Yu. Kostin / Elena D. Finashina / Konstantin B. Kalmykov / Gennady I. Kapustin / Petr V. Pribytkov / Olga P. Tkachenko / Igor V. Mishin / Leonid M. Kustov / Alexander L. Kustov

    Nanomaterials, Vol 13, Iss 936, p

    An Impact of the Support Nature on the Catalytic Cyclohexane Ring Opening

    2023  Volume 936

    Abstract: Because of the growing demand for high-quality fuels, the light cycle oil fraction improvement including cetane number improvement is important. The main way to reach this improvement is the ring opening of cyclic hydrocarbons, and a highly effective ... ...

    Abstract Because of the growing demand for high-quality fuels, the light cycle oil fraction improvement including cetane number improvement is important. The main way to reach this improvement is the ring opening of cyclic hydrocarbons, and a highly effective catalyst should be found. Cyclohexane ring openings are a possible option to investigate the catalyst activity. In this work, we investigated rhodium-loaded catalysts prepared using the commercially available industrial supports: single-component ones, SiO 2 and Al 2 O 3

    and mixed oxides CaO + MgO + Al 2 O 3 and Na 2 O + SiO 2 + Al 2 O 3 . The catalysts were prepared by incipient wetness impregnation and investigated by N 2 low-temperature adsorption-desorption, XRD, XPS, DRS UV-Vis and DRIFT spectroscopy, SEM, and TEM with EDX. The catalytic tests were performed in cyclohexane ring opening in the range of 275–325 °C. The best result was demonstrated by the sample 1Rh/CaMgAlO: the selectivity to n -hexane was about 75% while the cyclohexane conversion was about 25% at 275 °C. The space-time yield was up to 12 mmol n -hexane g cat −1 h −1 .
    Keywords rhodium ; support ; cyclohexane ; ring opening ; heterogeneous catalysis ; gas phase reaction ; Chemistry ; QD1-999
    Subject code 290
    Language English
    Publishing date 2023-03-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Does Background Matter? A Comparative Characterization of Mouse Models of Autosomal Retinitis Pigmentosa rd1 and Pde6b-KO

    Angelina V. Chirinskaite / Alexander Yu. Rotov / Mariia E. Ermolaeva / Lyubov A. Tkachenko / Anastasia N. Vaganova / Lavrentii G. Danilov / Ksenia N. Fedoseeva / Nicolay A. Kostin / Julia V. Sopova / Michael L. Firsov / Elena I. Leonova

    International Journal of Molecular Sciences, Vol 24, Iss 24, p

    2023  Volume 17180

    Abstract: Many retinal degenerative diseases result in vision impairment or permanent blindness due to photoreceptor loss or dysfunction. It has been observed that Pde6b rd1 mice (rd1), which carry a spontaneous nonsense mutation in the pde6b gene, have a strong ... ...

    Abstract Many retinal degenerative diseases result in vision impairment or permanent blindness due to photoreceptor loss or dysfunction. It has been observed that Pde6b rd1 mice (rd1), which carry a spontaneous nonsense mutation in the pde6b gene, have a strong phenotypic similarity to patients suffering from autosomal recessive retinitis pigmentosa. In this study, we present a novel mouse model of retinitis pigmentosa generated through pde6b gene knockout using CRISPR/Cas9 technology. We compare this Pde6b-KO mouse model to the rd1 mouse model to gain insights into the progression of retinal degeneration. The functional assessment of the mouse retina and the tracking of degeneration dynamics were performed using electrophysiological methods, while retinal morphology was analyzed through histology techniques. Interestingly, the Pde6b-KO mouse model demonstrated a higher amplitude of photoresponse than the rd1 model of the same age. At postnatal day 12, the thickness of the photoreceptor layer in both mouse models did not significantly differ from that of control animals; however, by day 15, a substantial reduction was observed. Notably, the decline in the number of photoreceptors in the rd1 model occurred at a significantly faster rate. These findings suggest that the C3H background may play a significant role in the early stages of retinal degeneration.
    Keywords retinitis pigmentosa ; pde6b ; β-subunit of phosphodiesterase ; electroretinography ; Pde6b-KO ; Biology (General) ; QH301-705.5 ; Chemistry ; QD1-999
    Subject code 616
    Language English
    Publishing date 2023-12-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Long-term follow-up study of post-COVID-19 patients

    Natalia A. Karchevskaya / Ivan M. Skorobogach / Alexander V. Cherniak / Ekaterina V. Migunova / Olga V. Leshchinskaya / Elena N. Kalmanova / Andrey Iu. Bulanov / Elena A. Ostrovskaya / Alexander I. Kostin / Valentina P. Nikulina / Natalia Iu. Kravchenko / Andrey S. Belevskiy / Sergey S. Petrikov

    Терапевтический архив, Vol 94, Iss 3, Pp 378-

    2022  Volume 388

    Abstract: Aim. To evaluate dynamic changes in the lungs, hemostasis system, immune system in different terms after coronavirus pneumonia. Materials and methods. Ventilation-perfusion single-photon emission computed tomography/computed tomography (CT), functional ... ...

    Abstract Aim. To evaluate dynamic changes in the lungs, hemostasis system, immune system in different terms after coronavirus pneumonia. Materials and methods. Ventilation-perfusion single-photon emission computed tomography/computed tomography (CT), functional methods of lung investigation, evaluation of hemostasis system, immune status and specific humoral immune response were performed and evaluated in different terms after coronavirus pneumonia. A total of 71 patients were examined according to this protocol. We examined patients with the lesion volume not less than 50% according to chest CT. All patients were divided into 2 groups depending on the distance from the acute stage of coronavirus pneumonia. Group 1 included patients who were examined early (3060 days after hospital discharge), group 2 included patients who were examined later (61180 days after hospital discharge). Results. We obtained gradual regression of pathologically-modified tissue from 67.3% during the inpatient phase to 30.9% during the early period and to 19.7% during the late period of examination, according to CT scan of the chest organs. The same tendency was demonstrated by diffusion capacity of the lungs. Perfusion scintigraphy data showed a decrease in perfusion deficit from 26.012.8% during the early period of examination to 19.46.2% during the late period of examination. On the contrary, ventilatory scintigraphy demonstrates the increase of isotope passage time through the alveolar-capillary membrane over time (from 48.231.3 minutes in the early period to 83.637.2 minutes in the late period). An increase in D-dimer was detected in 24% of patients in the early group. The levels of inflammatory markers, indices of immune status, and specific humoral immune response did not differ in the two described groups. Conclusion. The results demonstrate gradual regression of pathological changes caused by coronavirus infection.
    Keywords coronavirus infection ; respiratory function ; computed tomography ; v/q spect ct ; coagulogram ; inflammatory markers ; immunogram ; specific immune response ; post-covid-19 syndrome ; Medicine ; R
    Subject code 610
    Language Russian
    Publishing date 2022-03-01T00:00:00Z
    Publisher "Consilium Medicum" Publishing house
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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