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Distributed Dynamic Load in Structural Dynamics by the Impulse-Based Force Estimation Algorithm

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2865-2891页

作者： Yuantian Qin Yucheng Zhang vadim v.Silberschmidt College of Astronautics Nanjing University of Aeronautics and AstronauticsNanjing210016China Wolfson School of Mechanical Electrical and Manufacturing EngineeringLoughborough UniversityLoughboroughLE113TUUK

This paper proposes a novel approach for identifying distributed dynamic loads in the time *** polynomial andmodal analysis,the load is transformed intomodal space for coefficient *** allows the distributed dynamic load with a two-dimensional form in terms of time and space to be simultaneously identified in the form of modal force,thereby achieving dimensionality *** Impulse-based Force Estimation Algorithm is proposed to identify dynamic loads in the time ***,the algorithm establishes a recursion scheme based on convolution integral,enabling it to identify loads with a long history and rapidly changing forms over ***,the algorithm introduces moving mean and polynomial fitting to detrend,enhancing its applicability in load *** aforementioned methodology successfully accomplishes the reconstruction of distributed,instead of centralized,dynamic loads on the continuum in the time domain by utilizing acceleration *** validate the effectiveness of the method,computational and experimental verification were conducted.

关键词： Distributed force estimation time domain deconvolution recursion

Seasonal Dynamics of Male and Female Reproductive Systems in the Siberian Salamander, Salamandrella keyserlingii (Caudata, Hynobiidae)

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Asian Herpetological Research 2015年第3期6卷 169-183页

作者： vadim v.YARTSEv valentina N.KURANOvA Department of vertebrate Zoology and Ecology Institute of BiologyTomsk State University

It is not well known how low temperatures, like a subarctic steppe–tundra climate, influence reproductive traits of ectothermic vertebrates. To begin answering this question, we studied male and female reproductive systems of Salamandrella keyserlingii inhabiting a Tomsk population（southeast of Western Siberia）, Russia, in ecological and physiological terms. In males, before spermiation, the testicular size and weight in late April–early May were greatest of all. Spermiation occurred during breeding immigration in spring when mean air temperature was above 10°С, and at the same time rain fell. After spermiation, the testicular size and weight decreased sharply, and the diameter of the vasa deferentia increased. ＂Spawning＂（i.e., simultaneous extrusion of sperm and oviposition） occurred from late April to late May, and this duration fluctuated in temperature and humidity. The testicular size and weight increased in summer. Sperm mass was detected in the testes by the smear method in April–September, except in June when single fragmented unrealized sperm was detected and in July when spermatids were detected. In females, ovarian weight was greatest in spring before ovulation. From late June, vitellogenesis began in ovarian follicles, in which mint green yolks accumulated. Melanin deposited in the surface of the ovary from July when oviducts were hypertrophying. In contrast, some large-sized females did not show any sexual maturity shortly before hibernation（although these females may be subadults）. These results suggest that low temperatures in Siberia induce early timing of gamete maturation in females, but the females＇ reproductive cycle might also be biennial. A reproductive cycle in males was annual with the completion of the gamete maturation process in August.

关键词： annual reproductive cycle biennial reproductive cycle breeding immigration gamete maturation subarctic climate

SPH-BEM simulation of underwater explosion and bubble dynamics near rigid wall

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Science China(Technological Sciences) 2019年第7期62卷 1082-1093页

作者： ZHANG ZhiFan WANG Cheng ZHANG A-Man Silberschmidt vadim v WANG LongKan State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China College of Shipbuilding Engineering Harbin Engineering University Harbin 150001 China Wolfson School of Mechanical Electrical and Manufacturing Engineering Loughborough University Leicestershire LE11 3TU UK China Ship Research and Development Academy Beijing 100101 China

A process of underwater explosion of a charge near a rigid wall includes three main stages: charge detonation, bubble pulsation and jet formation. A smoothed particle hydrodynamics(SPH) method has natural advantages in solving problems with large deformations and is suitable for simulation of processes of charge detonation and jet formation. On the other hand, a boundary element method(BEM) is highly efficient for modelling of the bubble pulsation process. In this paper, a hybrid algorithm, fully utilizing advantages of both SPH and BEM, was applied to simulate the entire process of free and near-field underwater explosions. First, a numerical model of the free-field underwater explosion was developed, and the entire explosion process–from the charge detonation to the jet formation–was analysed. Second, the obtained numerical results were compared with the original experimental data in order to verify the validity of the presented method. Third, a SPH model of underwater explosion for a column charge near a rigid wall was developed to simulate the detonation process. The results for propagation of a shock wave are in good accordance with the physical observations. After that, the SPH results were employed as initial conditions for the BEM to simulate the bubble pulsation. The obtained numerical results show that the bubble expanded at first and then shrunk due to a differences of pressure levels inside and outside it. Here, a good agreement between the numerical and experimental results for the shapes, the maximum radius and the movement of the bubble proved the effectiveness of the developed numerical model. Finally, the BEM results for a stage when an initial jet was formed were used as initial conditions for the SPH method to simulate the process of jet formation and its impact on the rigid wall. The numerical results agreed well with the experimental data, verifying the feasibility and suitability of the hybrid algorithm. Besides, the results show that, due to t

关键词： underwater explosion SPH-BEM algorithm load characteristics

Modeling the vertical Distribution of the Milky Way’s Flat Subsystem Objects

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Research in Astronomy and Astrophysics 2023年第1期23卷 254-267页

作者： Igor’I.Nikiforov vadim A.Usik Angelina v.veselova Saint Petersburg State University Universitetskij Prospekt 28Staryj PeterhofSaint Petersburg 198504Russia

This paper is an initial stage of consideration of the general problem of joint modeling of the vertical structure of a Galactic flat subsystem and the average surface of the disk of the Galaxy,taking into account the natural and measurement *** approximate the average surface of the Galactic disk in the region covered by the data with a general(polynomial)model and determine its parameters by minimizing the squared deviations of objects along the normal to the model *** smoothness of the model,i.e.,its order n,is *** outlier elimination algorithm is *** developed method allows us to simultaneously identify significant details of the Galactic warping and estimate the offset z_(⊙) of the Sun relative to the average(in general,non-flat)surface of the Galactic disk and the vertical scale of the object system under consideration for an arbitrary area of the disk covered by *** method is applied to data on classical *** local extremes of the average disk surface model were found based on Cepheid data:the minimum in the first Galactic quadrant and the maximum in the second.A well-known warp(lowering of the disk surface)in the third quadrant has been *** optimal order of the model describing all these warping details was found to be n_(o)=*** local(for a small neighborhood of the Sun,n_(o)=0)estimate of z_(⊙)=28.1±6.1|_(stat).±1.3|_(cal).pc is close to the non-local(taking into account warping,n_(o)=4)z_(⊙)=27.1±8.8|_(stat.-1.2)^(+1.3)|_(cal).pc(statistical and calibration uncertainties are indicated),which suggests that the proposed modeling method eliminates the influence of warping on the z_(⊙) ***,the non-local estimate of the vertical standard deviation of Cepheids σ_(p)=132.0±3.7|_(stat.-5.9)^(+6.3)|_(cal).pc differs significantly from the local σ_(ρ)=76.5±4.4|_(stat.-3.4)^(+3.6)|_(cal).pc,which implies the need to introduce more complex models for the vertical distribution outside the

关键词： Galaxy disk-Galaxy structure-Galaxy fundamental parameters-methods data analysis

Risk factors and urinary biomarkers of non-albuminuric and albuminuric chronic kidney disease in patients with type 2 diabetes

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World Journal of Diabetes 2019年第11期10卷 517-533页

作者： Anton I Korbut vadim v Klimontov Ilya v vinogradov vyacheslav v Romanov Laboratory of Endocrinology Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and GeneticsSiberian Branch of Russian Academy of Sciences(RICEL-Branch of IC&G SB RAS)Novosibirsk 630060Russia Clinical Laboratory “MBU-Technology”ltd.Novosibirsk 630090Russia

BACKGROUND A number of recent studies indicate a transformation in the natural course of chronic kidney disease(CKD)in type 2 diabetes(T2D)patients:an increasing prevalence of declined renal function without proceeding to the accompanying elevation of *** has been suggested that albuminuric and nonalbuminuric CKD patterns could be different in their phenotypes and pathogenic *** To identify the risk factors and biomarkers of albuminuric and non-albuminuric patterns of CKD in patients with *** Three hundred sixty patients with T2D duration≥10 years were included in this observational cross-sectional *** associations of a panel of demographic and clinical characteristics,complications,comorbidities,and metabolic and hematology parameters with albuminuric and non-albuminuric CKD patterns were *** urinary excretion of nephrin and podocin,two podocytespecific markers,and WAP-four-disulfide core domain protein 2(WFDC-2),a marker of tubulointerstitial fibrosis,was determined by ELISA in comparison with healthy *** Non-albuminuric CKD was associated with age≥65 years(P=0.0001),female sex(P=0.04),diabetes duration≥15 years(P=0.0009),and the use of diuretics(P=0.0005).Male sex(P=0.01),smoking(P=0.01),waist-to-hip ratio>1.0(P=0.01)and hemoglobin A1c(HbA1c)>8.0%(P=0.005)were risk factors for elevated albuminuria not accompanied by a decrease in estimated glomerular filtration rate(eGFR).Duration of diabetes≥15 years and the use of calcium channel blockers were risk factors for albuminuria with decreased eGFR(both P=0.01).In multivariate logistic regression analysis,age,HbA1c,female sex and diuretics were significant predictors for reduced eGFR,while waist-to-hip ratio,HbA1c and male sex were associated with elevated urinary albumin-to-creatinine ratio(UACR).Excretion of nephrin and podocin was increased in patients with albuminuria,regardless of decline in renal function(Pvely with *** urin

关键词： Diabetes mellitus Chronic kidney disease Albuminuria Glomerular filtration rate Podocytes Risk factors Biomarkers

Exhaust Cleaning with Dielectric Barrier Discharge

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Plasma Science and Technology 2010年第6期12卷 688-691页

作者： vadim Yu.PLAKSIN Oleksiy v.PENKOv Min Kook KO Heon Ju LEE Department of Nuclear & Energy Engineering Jeju National University

To clean the exhaust emissions as one of the most important tasks in pollution control, a study on the treatment of engine emissions with discharge assistance was reported. A DBD plasma source shaped in grid and cylinder was examined in different engine operational modes to reduce the NOx content of diesel engine exhaust. The composition of the exhaust gases and chemical reactions initiated by the discharge were analyzed. The discharge frequency had a crucial impact on the device＇s performance and gas treatment. The voltages applied to the discharge gap could alter the chemical reactions occurring in the treated gases, which were indicated by the NO to NO2 ratio. The operation of the system was studied at frequencies ranging from 400 Hz to 16 kHz.

关键词： dielectric barrier discharge diesel engine emissions NOx atmospheric pressure

Thermo-and pH-sensitive Polymer with Pendant Spacer-linked Imidazole Cycles

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Chinese Journal of Polymer Science 2024年第4期42卷 437-445页

作者： Natalya v.Zakharova Stanislav N.Zelinskiy Mariya S.Strelova Elena N.Danilovtseva vadim v.Annenkov Institute of Macromolecular Compounds of the Russian Academy of Sciences Saint Petersburg199004Russia Limnological Institute of Siberian Branch of the Russian Academy of Sciences Irkutsk664033Russia

By the reaction of poly(acryloyl chloride) with N-(3-aminopropyl)imidazole, poly(N-(3-(1H-imidazol-1-yl)propyl)acrylamide) was synthesized. The new polymer contains an imidazole ring removed from the main chain by a spacer of five bonds. The structure and purity, molecular weight, hydrodynamic and thermosensitive properties of the obtained sample were studied by1H-and13C-NMR, FTIR spectroscopy, acid-base titration, light scattering, turbidimetry and viscometry. The observed ability of the imidazole-containing polymer to form and destroy associates in water-salt solutions at pH 6.6-7.4 and temperatures of 29-48℃ indicates that these are promising candidates for designing complex biomedical systems. The new polymer is able to form complexes with oligo-DNA more actively than poly(1-vinylimidazole), which is of interest for gene delivery applications. The polymer cross-linked with epichlorohydrin gives micro-relief coatings on the plastic surface, and the modified surface is able to attach negatively charged objects. This thermo-and pH-sensitive polymer modification can be applied to create finely controlled surfaces for cell culturing.

关键词： Imidazole-containing polymer Thermolability pH-sensitivity The modified surface DNA immobilization

Factors associated with trabecular bone score in postmenopausal women with type 2 diabetes and normal bone mineral density

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World Journal of Diabetes 2022年第7期13卷 553-565页

作者： Olga N Fazullina Anton I Korbut vadim v Klimontov Laboratory of Endocrinology Research Institute of Clinical and Experimental Lymphology-Branch of the Institute of Cytology and GeneticsSiberian Branch of Russian Academy of SciencesNovosibirsk 630060Russia

BACKGROUND Osteoporosis and type 2 diabetes(T2D)have been recognized as a widespread comorbidity leading to excess mortality and an enormous healthcare *** T2D,bone mineral density(BMD)may underestimate the risk of low-energy fractures as bone quality is *** was hypothesized that a decrease in the trabecular bone score(TBS),a parameter assessing bone microarchitecture,may be an early marker of impaired bone health in women with *** To identify clinical and body composition parameters that affect TBS in postmenopausal women with T2D and normal *** A non-interventional cross-sectional comparative study was *** eligible subjects were screened at tertiary referral *** women with T2D,aged 50-75 years,with no established risk factors for secondary osteoporosis,were ***,TBS and body composition parameters were assessed by dual-energy X-ray *** women with normal BMD,a wide range of anthropometric,general and diabetes-related clinical and laboratory parameters were evaluated as risk factors for TBS decrease using univariate and multivariate regression analysis and analysis of receiver operating characteristic(ROC)*** Three hundred twelve women were initially screened,176 of them met the inclusion criteria and underwent dual X-ray *** with reduced BMD were subsequently excluded;96 women with normal BMD were included in final *** them,43 women(44.8%)showed decreased TBS values(≤1.31).Women with TBS≤1.31 were taller and had a lower body mass index(BMI)when compared to those with normal TBS(Р=0.008 and P=0.007 respectively).No significant differences in HbA1c,renal function,calcium,phosphorus,alkaline phosphatase,PTH and 25(ОН)D levels were *** a model of multivariate linear regression analysis,TBS was positively associated with gynoid fat mass,whereas the height and androgen fat mass were associated negatively(all P<0.001).In a multiple logistic regres

关键词： Diabetes Osteoporosis Bone mineral density Trabecular bone score Obesity Body composition

Physiological significance of oxidative stress and its role in adaptation of the human body to deleterious factors

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Frontiers in Biology 2018年第1期13卷 19-27页

作者： vadim v. Davydov Alexander v. Shestopalov Evgenya R. Grabovetskaya Chair of biochemistry and molecular biology Pirogov Russian National Research Medical University Moscow 117997 Russia Chair of biochemistry v.N. Karazin Kharkov National University Ukraine Kharkov 61077 Ukraine

BACKGROUND： Oxidative stress is an extremely widespread condition manifested in an increased rate of free-radical processes and accumulation of reactive oxygen species （ROS） in the tissues. It appears in different physiologic states and pathological processes accompanied by stimulation of the sympathetic adrenal system or tissue hypoxia or under stress. However, until now, there is still no clarity on the issue of the significance of oxidative stress in the development of adaptation processes in the organism. OBJECTIvE： In the present work we will review the most recent finding about physiologic role of oxidative stress and its participation in adaptation of an organism to effect of different adverse factors. METHODS： A systematic literature search was performed using the Pubmed search engine. Studies published over past 18 years, i.e. between 1998 and 2015 were considered for review. Followed keywords were used：＂oxidative stress,＂＂free radical oxidation,＂＂ROS,＂＂endogenous aldehydes,＂＂adaptation.＂ RESULTS： The article cites arguments supporting the notion that oxidative stress serves as a nonspecific link in the adaptation of the human body to the effects of injurious factors. Oxidative stress exerts regulatory effects by changing the redox state of the cell. Oxidative stress affects on various intracellular proteins containing cysteine residues, e.g., enzymes, chaperones, and transcription factors, etc. For this reason, the use of antioxidants for the treatment and prophylaxis of a wide range of diseases is not recommended. CONCLUSION： Further investigation is needed in this field. The most attention should be paid to careful experimental verification aimed at quantitative assessment of the ROS level in tissues under oxidative stress, as well as at the study of possibility of enhancing the catabolism of free radical oxidation carbonyl products in order to prevent tissue damage under oxidative stress.

关键词： oxidative stress free radical oxidation ROS adaptation endogenous aldehydes