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Multi-layered tissue head phantoms for noninvasive optical diagnostics

Journal of Innovative Optical Health Sciences 2015年第3期8卷 36-45页

作者： M.S.Wróbel a.p.popov A.V.Bykov M.Kinnunen M.Jędrzejewska-Szczerska V.V.Tuchin Department of Metrology and Optoelectronics Gdansk University of Technology Gabriela Narutowicza Street 11/1280-233 Gdansk Poland Optoelectronics and Measurement Techniques Laboratory Faculty of Information Technology and Electrical Engineering University of Oulu P.O.Box 4500 FI-90014 OuluFinland Research-Educational Institute of Optics and Biophotonics Saratov State University Saratov 410012Russia Institute of precise Mechanics and Control Russian Academy of Sciences Saratov 410028Russia

Extensive research in the area of optical sensing for medical diagnostics requires development of tissue phantoms with opt ical properties similar to those of living human tissues.Development and improvement of in vivo optical measurement systems requires the 1use of stable tissue phantoms with known characteristics,which are mainly used for calibration of such systems and testing their performance over time.Optical and mechanical properties of phantoms depend on their purpose.Nevertheless,they must accurately simulate specific tssues they are supposed to mimic.Many tsues and organs including head possess a multi-layered structure,with specifie optical properties of each layer.However,such a structure is not always addressed in the present-day phantoms.In this paper,we focus on the development of a plain-parallel multi-layered phantom with optical properties(reduced scattering oofficientμ'and absorption cofficientμa)corresponding to the human head layers,such as skin,skul,and gray and white matter of the brain tissue.The phantom is intended for use in noninvasive diffuse near-infrared spectroscopy(NIRS)of humnan brain.Optical parameters of the fabricated phantoms are reconstructed using spectrophotometry and inverse adding-doubling calculation method.The results show that polyinyl chloride plastisol(pVCp)and zinc oxide(ZnO)nanoparticles are suitable materials for fabrication of tissue mimicking phantoms with controlled scattering properties.Good matching was found between optical properties of phantoms and the corresponding values found in the literature.

关键词： Tissue-mimicking phantoms optical properties near-infrared spectroscopy head model

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Approximate contact solutions for non-axisymmetric homogeneous and power-law graded elastic bodies:A practical tool for design engineers and tribologists

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Friction 2024年第2期12卷 340-355页

作者： Valentin L.popov Qiang LI Emanuel WILLERT Institute of Mechanics Technische Universität BerlinBerlin 10623Germany

In two recent papers,approximate solutions for compact non-axisymmetric contact problems of homogeneous and power-law graded elastic bodies have been suggested,which provide explicit analytical relations for the force–approach relation,the size and the shape of the contact area,as well as for the pressure distribution therein.These solutions were derived for profiles,which only slightly deviate from the axisymmetric shape.In the present paper,they undergo an extensive testing and validation by comparison of solutions with a great variety of profile shapes with numerical solutions obtained by the fast Fourier transform(FFT)-assisted boundary element method(BEM).Examples are given with quite significant deviations from axial symmetry and show surprisingly good agreement with numerical solutions.

关键词： normal contact non-axisymmetric indenter extremal principle generalized method of dimensionality reduction(MDR) functional elastic grading

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physiological strategies in wild rodents:immune defenses of commensal rats

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Integrative Zoology 2024年第3期19卷 350-370页

作者： Ivana MIRKOV Dina TUCOVIC Jelena KULAS Anastasija MALESEVIC Dragan KATARANOVSKI Milena KATARANOVSKI Aleksandra popov ALEKSANDROV Immunotoxicology Group Department of EcologyInstitute for Biological Research“Sinisa Stankovic”—National Institute of Republic of SerbiaUniversity of BelgradeBelgradeSerbia

The importance of issues associated with urban/commensal rats and mice(property damage,management costs,and health risks)press upon research on these animals.While the demography of commensal rodents is mostly studied,the need for understanding factors influencing their natural morbidity/mortality is also stressed.In this respect,more attention is expected to be paid to immunity,the physiological mechanism of defense against host survival threats(pathogens,parasites,diseases).Commensal rats and mice carry numerous pathogens that evoke diverse immune responses.The state of immunity in commensal house mice is studied in great detail,owing to the use of laboratory strains in biomedical research.Because commensal rats are,compared to mice,carriers of more zoonotic agents,rats’immunity is studied mainly in that context.Some of these zoonotic agents cause chronic,asymptomatic infections,which justified studies of immunological mechanisms of pathogen tolerance versus clearance regulation in rats.Occurrence of some infections in specific tissues/organs pressed upon analysis of local/regional immune responses and/or immunopathology.A survey of immunological activity/responses in commensal rats is given in this review,with mention of existing data in commensal mice.It should throw some light on the factors relevant to their morbidity and lifespan,supplementing the knowledge of commensal rodent ecology.

关键词： commensal rats and mice immunopathology infection inflammation tolerance

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High-performance portable grating-based surface plasmon resonance sensor using a tunable laser at normal incidence

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photonics Research 2024年第5期12卷 947-958页

作者： Duc LE ANNI RANTA-LASSILA TEEMU SIpOLA MIKKO KARppINEN JARNO pETAJA MINNA KEHUSMAA SANNA AIKIO TIAN-LONG GUO MATTHIEU ROUSSEY JUSSI HILTUNEN ALEXEY popov VTT Technical Research Centre of Finland 90570 OuluFinland Department of physics and Mathematics University of Eastern FinlandFI-80101 JoensuuFinland

Surface plasmon resonance(SpR)sensors are among the most sensitive sensors.In such devices,a grating is a compelling alternative to a prism for the excitation of a surface plasmon,especially in the development of sensors for point-of-care applications due to their compactness and cost-effectiveness.Here,we demonstrate the use of a tunable laser in a grating-based SpR system for further miniaturization and integration.The tunable laser working at normal incidence replaces spectral and moving components,while also simplifying the optical setup.Normal incidence is conventionally avoided due to the complexity of the control of degenerated SpR modes.We investigate,both computationally and experimentally,the splitting of the SpR modes at small nonzero incidences,which is lacking in previously reported studies.By optimizing the grating configuration,we were able to diminish the SpR mode splitting phenomenon when the excitation was feasible with the normal incidence configuration.The fabricated sensor showed a high sensitivity of 1101.6 nm/RIU.Notably,the figure of merit of the sensor,defined as the ratio between the sensitivity and bandwidth of the SpR dip,was 229.5.The experimental results were consistent with the simulation results.We also demonstrate its capability for detecting low concentrations of glucose and creatinine with the limit of detection of 14.2 and 19.1 mmol/L,respectively.

关键词： tunable splitting excitation

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Atherosclerosis originating from childhood:Specific features

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Journal of Biomedical Research 2024年第3期38卷 233-240页

作者： Anastasia V.poznyak Alexey A.Yakovlev MikhailА.popov Elena B.Zhigmitova Vasily N.Sukhorukov Alexander N.Orekhov Institute for Atherosclerosis Research Moscow 121609Russia Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology Moscow 109240Russia Department of Cardiac Surgery Moscow Regional Research and Clinical InstituteMoscow 129110Russia Laboratory of Angiopathology Institute of General Pathology and PathophysiologyMoscow 125315Russia

Atherosclerosis is extremely widespread.Traditionally,it is considered a disease of older people,who most often experience problems with the heart and blood vessels.While much attention from the scientific community has been paid to studying the association between aging and atherosclerosis,as well as its consequences,there is evidence that atherosclerosis occurs at an early age.Atherosclerosis may form both during intrauterine development and in childhood.Nutrition plays an important role in childhood atherosclerosis,along with previous infectious diseases and excess weight of both the child and the mother.In the present review,we examined the development of atherosclerosis and the prerequisites in childhood.

关键词： atherosclerosis childhood pediatrics cardiovascular disease

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Transient expression of inactive RB in mesenchymal stem cells impairs their adipogenic potential and is associated with hypermethylation of the ppARγ2 promoter

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Genes & Diseases 2022年第1期9卷 165-175页

作者： Mikhail Baryshev Nikolai petrov Vladimir Ryabov Boris popov Institute of Cytology Russian Academy of Sciences St.Petersburg4Tikhoretsky Av.194064St.PetersburgRussia Institute of Microbiology and Virology Riga Stradins UniversityRatsupites 5LV-1067RigaLatvia Developmental Therapeutics Branch National Cancer InstituteNational Institutes of HealthBethesdaMaryland 20892USA

The retinoblastoma gene product(pRb)is a chromatin-associated protein that can either suppress or promote activity of key regulators of tissue-specific differentiation.We found that twelve weeks after transfection of the exogenous active(ΔB/X andΔр34)or inactive(ΔS/N)forms of RB into the 10T1/2 mesenchymal stem cells and clonal selection not a single cell line did contain exogenous RB,despite being G-418 resistant.However,the consequences of the transient production of exogenous RB had different effects on the cell fate.TheΔB/X andΔр34 cells transfected with active form of RB showed elevated levels of inducible adipocyte differentiation(AD).On the contrary,theΔS/N cells transfected with inactive RB mutant were insensitive to induction of AD associated with abolishing of expression of the ppARγ2.Additionally,the ppARγ2 promoter in undifferentiatedΔS/N cells was hypermethylated,but all except−60 position CpG became mostly demethylated after cells exposure to AD.We conclude that while transient expression of inactive exogenous RB induces long term epigenetic alterations that prevent adipogenesis,production of active exogenous RBs results in an AD-promoting epigenetic state.These results indicate that pRb is involved in the establishment of hereditary epigenetic memory at least by creating a methylation pattern of ppARγ2.

关键词： Adipogenic differentiation DNA methyltransferase 1 Mesenchymal stem cells MSCs RB Retinoblastoma susceptibility gene

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Experimental and Numerical Assessment of the Influence of Bottomhole pressure Drawdown on Terrigenous Reservoir permeability and Well productivity

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Fluid Dynamics & Materials processing 2023年第3期19卷 619-634页

作者： Sergey popov Sergey Chernyshov Evgeniy Gladkikh Oil and Gas Research Institute of Russian Academy of Science Moscow119333Russian perm National Research polytechnic University Perm614990Russian

During oil and gas fields development,a decrease in reservoir and bottomhole pressure has often a detrimental effect on reservoir properties,especially permeability.This study presents the results of laboratory tests conducted to determine the response of terrigenous reservoir core-sample permeability to changes in the effective stresses and a decrease in the reservoir pressure.The considered samples were exposed for a long time to a constant high effective stress for a more reliable assessment of the viscoplastic deformations.According to these experiments,the decrease of the core samples permeability may reach 21%with a decrease in pressure by 9.5 Mpa from the initial reservoir conditions.Numerical simulations have been also conducted.These have been based on the finite element modeling of the near-wellbore zone of the terrigenous reservoir using poroelasticity relations.The simulation results show a limited decrease in reservoir permeability in the near-wellbore zone(by 17%,which can lead to a decrease in the well productivity by 13%).

关键词： Terrigenous reservoir permeability core sample reservoir pressure bottomhole pressure drawdown effective stress well productivity

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prompt neutron emission in 250No spontaneous fission associated with ground and isomeric state decays

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Chinese physics C 2024年第6期48卷 112-117页

作者： R.S.Mukhin A.V.Isaev A.V.Andreev M.L.Chelnokov V.I.Chepigin H.M.Devaraja I.N.Izosimov A.A.Kuznetsova O.N.Malyshev A.G.popeko Yu.A.popov A.Rahmatinejad B.Sailaubekov T.M.Shneidman E.A.Sokol A.I.Svirikhin M.S.Tezekbayeva M.A.Bychkov A.V.Yeremin O.Dorvaux B.Gall K.Kessaci K.Hauschild A.Lopez-Martens Joint Institute for Nuclear Research Dubna141980Russia Dubna State University Dubna141982Russia Institute of Nuclear physics Almaty050032Kazakhstan L.N.Gumilyov Eurasian National University Astana010008Kazakhstan Kazan Federal University Kazan420008Russia Universitéde Strasbourg CNRSStrasbourg67000France IJCLab IN2P3-CNRSUniversitéParis-SaclayOrsay91400France

The complete-fusion reaction^(204)pb(^(48)Ca,2n)^(250)No was used to study two activities of^(250)No with distinct half-lives.A total of 1357 events were observed in the SFiNx neutron detection system.The average number of neutrons emitted per spontaneous fission of^(250)No was determined to be(4.1±0.1).The unusually symmetrical shape of the prompt neutron multiplicity distribution was restored and presented for the first time.Statistical tests were performed to compare the prompt neutron multiplicity distributions associated with the ground state and K-isomer state decays.

关键词： spontaneous fission prompt neutrons actinide

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Second-Order Invariant Domain preserving ALE Approximation of Euler Equations

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Communications on Applied Mathematics and Computation 2023年第2期5卷 923-945页

作者： Jean-Luc Guermond Bojan popov Laura Saavedra Department of Mathematics Texas A&M UniversityCollege StationUSA Departamento de Matemática Aplicada a la Ingeniería Aeroespacial Universidad Politécnica de MadridMadridSpain

An invariant domain preserving arbitrary Lagrangian-Eulerian method for solving non-linear hyperbolic systems is developed.The numerical scheme is explicit in time and the approximation in space is done with continuous finite elements.The method is made invar-iant domain preserving for the Euler equations using convex limiting and is tested on vari-ous benchmarks.

关键词： Conservation equations Hyperbolic systems Arbitrary Lagrangian-Eulerian Moving meshes Invariant domains High-order method Convex limiting Finite element method

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Structural and geochemical features of coal‑bearing sediments and sources of rare element impurities in coals of the Rakovka depression,primorsky Krai,Russia

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International Journal of Coal Science & Technology 2022年第1期9卷 71-83页

作者： Nikita popov Igor Chekryzhov Irina Tarasenko Sergery Kasatkin Aleksei Kholodov Far East Geological Institute FEB RAS VladivostokRussian Federation

There are known brown coal deposits in primorsky Krai(Russian Federation),where coals contain rare elements(Ge,U,REE,etc.)up to industrial concentrations.One of the known metalliferous coals is the Rakovka coal-bearing depression,located on the southern edge of the Khanka(prikhankaiskaya)Lowland,with an area of about 70 km2.Rare-metal granites with a developed weathering crust are spread in its basement and flanks.The structural conditions forming the depression were studied using measurements of orientations of structural elements(layering,contacts,veins,and dikes)with regard to kinematic conditions of faulting.The coal and host rocks were sampled in sections in the cross strike of the coal seam.Granites and dikes cutting them were sampled by separate rock chip samples.The chemical composition and element content were determined for all samples.It was found that the adjacent rocks played a major role in the formation of the Rakovka rare-metal-coal deposit.The rare-elements enrichment is not associated with active tectonics,faults,and hydrothermal sources,as was previously assumed.Rather,it was caused by the hydrogenic and clastogenic removal of these metals from the weathering crust of granites of the depression's flanks and argillated basite dikes cutting the granites.The hydrogenic nature of the anomalous accumulation of U in sorbed form on organic matter of coals is confirmed by the predominant enrichment of low-ash beds.Rare earth elements entered coal seams both in mineral and dissolved forms.A model of REE and uranium input into the coal-bearing sediments of the Rakovka depression was proposed.

关键词： REE Rare metal-coal deposit Accumulation pattern Tectonics

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