Mechanism Of Stress Generation Research Articles

Total Oxidative Index Is Associated with Glycated Hemoglobin, Low-Grade Inflammation, and Non-HDL Cholesterol in Type 2 Diabetes

Objectives: To study associations of established cardiovascular risk factors, inflammation and carotid artery intima-media thickness (CIMT) with oxidative stress in type 2 diabetes mellitus (T2DM). Methods: We recruited 343 T2DM subjects from the three main ethnic groups in Singapore (Chinese: 196, Indians: 106, Malays: 41; Age: 54.7±10.4 years; Males: 46%). Measurements: Demographics, BMI, blood pressure, HbA1c, glucose and lipids; CIMT and C-reactive protein (hsCRP). Derivatives of reactive oxygen metabolites (dROMS) and total anti-oxidant status (TAC) was estimated by the automated clinical chemistry analyser (Diacron, Italy). The total oxidative index (OXY) was calculated as the difference between standardised dROMS and TAC values. The relationship between OXY, dROMS and TAC as dependent variable and age, gender, ethnicity, BMI, blood pressure, HbA1c, fasting lipids, log CRP and CIMT as co-variates was assessed using multiple regression analysis. Associations with gender and ethnicity were assessed by student’s t test and Kruskal Wallis test respectively. Results: The mean OXY was higher in the females (0.2±1.3) compared to the males (0.2±1.0); p<0.001 and highest in the Indians (0.3±1.2) when compared to Chinese (-0.1±1.2) and Malays (-0.1±1.0); p=0.01. OXY exhibited a linear relationship with HbA1c (β=0.09, p=0.01), Non-HDL cholesterol ((β=0.28, p<0.001) and CRP (β=0.21, p<0.001). dROMS associated with HbA1c (β=5.3, p=0.04) and CRP (β=14.80, p<0.001) and TAC associated inversely with non-HDL-cholesterol (β= -121.4, p<0.001). No association with CIMT was seen. Conclusions: In T2DM, total oxidative stress is a function of HbA1c, non-HDL-Cholesterol and low-grade inflammation. HbA1c and inflammation increase reactive oxygen metabolites, whereas non-HDL cholesterol decreases the anti-oxidant potential. The mechanisms of oxidative stress generation, in particular in various ethnic groups, needs to be studied further. Disclosure R. Dalan: None. L. Goh: None. X. Tang: None. D.E.K. Chew: None. B. Boehm: None.

The Effect of Different Additives in the in-Situ Stress of Thin Co Films

Fe, Co and Ni (and their alloys) are widely used due to their interesting ferromagnetic, chemical, and physical properties. Electrodeposited thin films tend to develop sizable mechanical stresses as a result of the nucleation and growth process. Often, these stresses can approach or exceed the yield stress of the bulk material and can lead to loss of adhesion and the generation of bulk and surface defects. Models have been developed that treat steady-state stress as a dynamic competition between tensile and compressive stress generation mechanisms that are largely governed by atomic mobility, microstructure, and deposition rate. Although additives are often used to mitigate residual stress during thin film growth, the exact mechanisms by which these additives influence residual stress is an active area of research. In this talk, we examine the growth stress associated with electrodeposition of Co thin films onto (111)-textured Au cantilever electrodes from 0.5 M Na2SO4 containing 0.1 M CoSO4 and 0.5 M H3BO3. The stress was measured with an optical cantilever curvature technique that can be used during deposition to determine the real-time stress evolution. Deposition was also examined using an electrochemical quartz crystal microbalance (EQCM) in order to determine the current efficiency as a function of both overpotential and deposition time. We have measured the average biaxial film stress as a function of overpotential and observe a significant increase in tensile stress as the deposition potential is made more negative. These results are discussed in the context of stress generating models that appear in the literature. The growth stress was also examined from 0.5 M Na2SO4 + 0.1 M CoSO4 electrolyte with controlled additions of glycine and boric acid. Each additive was studied under a specific potential window, as determined by the observed influence the additives have on Co deposition. Glycine acts as a buffer, maintaining a stable H+ concentration. The buffering product glycinate (Gly-) complexes with Co2+, thereby shifting the deposition window. Baths with boric acid have an average current efficiency between 40 and 90%, produce deposits with high tensile stress which undergo little postdeposition relaxation. Current efficiency from glycine baths range between 20 and 70%. Deposits generally have lower tensile stress and exhibit additional post-deposition stress relaxation.

Stress generation and evolution in oxide heteroepitaxy

Many physical properties of oxides can be changed by inducing lattice distortions in the crystal through heteroepitaxial growth of thin films. The average lattice strain can often be tuned by changing the film thickness or using suitable buffer layers between film and substrate. The exploitation of the full potential of strain engineering for sample or device fabrication rests on the understanding of the fundamental mechanisms of stress generation and evolution. For this study an optical measurement of the substrate curvature is used to monitor in situ how the stress builds up and relaxes during the growth of oxide thin films by pulsed laser deposition. The relaxation behavior is correlated with the growth mode, which is monitored simultaneously with reflection high-energy electron diffraction. The stress relaxation data is fitted and compared with theoretical models for stress evolution which were established for semiconductor epitaxy. The initial stage of the growth appears to be governed by surface stress and surface energy effects, while the subsequent stress relaxation is found to be fundamentally different between films grown on single-crystal substrates and on buffer layers. The first case can be rationalized with established theoretical models, but these models fail in the attempt to describe the growth on buffer layers. This is most probably due to the larger average density of crystalline defects in the buffer layers, which leads to a two-step stress relaxation mechanism, driven first by the nucleation and later by the migration of dislocation lines.

Emotional and Social Reactivity as Mechanisms of Stress Generation: A Momentary Assessment Study

Depressed individuals report higher rates of stressful daily interpersonal events. The stress generation hypothesis suggests that traits and behaviors associated with depression may actually cause these stressors to occur. The exact day-to-day emotional and behavioral processes that drive stress generation, however, are less well understood. The present study uses experience sampling methods in a sample of 110 female undergraduate students to examine hour-by-hour emotional and social reactivity and avoidance coping as possible contributors to stress generation. Participants reported on overall symptoms of depression and then completed four daily diaries per day over a five-day period on emotional state, stressful interpersonal experiences, and avoidance behaviors. Multilevel models revealed that emotional distress both generated and was generated by interpersonal stressors such as conflict, rejection, or criticism. Avoidant behavioral responses to stressors—such as social withdrawal, substance use, or ignoring a problem—also significantly contributed to negative mood: Emotional reactivity was thus amplified by problem avoidance. Individuals who reported more depressive symptoms were especially likely to respond to negative moods with avoidance behavior. Ramifications for clinical interventions that focus on reducing emotional reactivity and avoidance coping are discussed.

The closed form solutions for axisymmetric modeling of thermal stress due to repetitive pulse laser heating

• Novel closed form solutions for axisymmetric modeling of thermal stress induced by repetitive pulse laser heating are obtained. • Thermal stress distributions for different radial and axial locations of material are modeled and analyzed. • Mechanisms of energy gain and stress generation for different laser irradiation regions are analyzed. • Effects of duty cycles on thermal stress distributions are investigated. Repetitive pulse laser heating is increasingly being used in the laser processing industry such as laser welding, laser cutting and laser drilling due to its energy accumulation effect. Modeling of thermo-mechanical coupling effect of repetitive pulse laser heating can enhance the understanding of its thermo physical process. In this paper, an axisymmetric modeling of thermal stress for repetitive pulse laser heating solid materials is introduced, and its closed form solutions are obtained based on a semi-analytical method. The accuracy and efficiency of the closed form solutions are verified by comparison with the existing numerical modeling software based on the finite element method. Distributions of thermal stress for different radial locations, axial locations and duty cycles are calculated, and effects of these parameters on temporal profile of the thermal stress distributions are analyzed. In the region of laser irradiation, three components of thermal stress are all shown as compressive stress. And outside the region of laser irradiation, the hoop component is shown as tensile stress. On the material surface, the change of thermal stresses is very sharp as a result of direct absorption of incident laser energy. With the increasing of the depth, the rises and decreases of thermal stresses become smooth gradually. The duty cycle has a significant effect on the profiles of thermal stresses. In the same conditions, the maximum value of thermal stresses gets higher as the duty cycle decreases. Results of this study can provide some theoretical basis for parameter inversion and optimization of repetitive pulse laser heating, as well as some corresponding experimental research.

Model of Stress Generation in Anodic Aluminum Oxide Films: Part I. Origin of Stress at the Film Interfaces

Stress builds up near the interfaces of anodic aluminum oxide layers prior to formation of self-organized arrays of pores. Pore initiation may result from a viscous flow instability driven by interfacial stress gradients. We examined the mechanism of interfacial stress generation through a model of coupled viscous flow and ionic migration during growth of planar anodic aluminum oxide layers. In the model, diffusion-induced stress is produced at the oxide-solution interface because deposition of new oxide is constrained by strong adsorption of electrolyte oxyanions. Stress distributions were calculated for barrier oxide growth in phosphoric acid, using values of ion migration parameters and oxide viscosity from independent experimental results. Both the stress layer thickness of a few nanometers and the magnitude of the interfacial stress agreed with those found experimentally. The model also correctly predicted transitions between compressive and tensile stress at the oxide-solution and metal-oxide interfaces at critical current densities. The thin stress layer at the solution interface can be viewed as effective surface tension dependent on the local current density. The current distribution on a nonplanar interface would induce surface tension gradients resulting in shear and normal stress in the oxide, and these in turn could drive oxide flow leading to self-organized porous films.

О ГЕНЕЗИСЕ НАПРЯЖЕНИЙ В КОРЕ ОСТРОВНОЙ ДУГИ ПО РЕЗУЛЬТАТАМ ЧИСЛЕННОГО МОДЕЛИРОВАНИЯ

The article describes the mechanism of stress generation in the Japanese island arc on the Pacific active continental margin. The research is based on the results of tectonophysical reconstruction of natural stresses and numerical geomechanical simulation. Mathematical modeling was made in a two-dimensional elastic-plastic formulation using the finite difference method (Wilkins); the main parameter under study was the structure of the obtained stress state (orientation of the principal axes of the stress tensor and other parameters of the physical state). The study showed that the pressure, caused by the Pacific spreading zone, forms a regime of horizontal compression both in the crusts of the ocean and continental slopes. Although the loading regime, corresponding to the convection in the asthenosphere, did not fully comply with the data on natural stresses, but yet showed stress distributions more close to the natural ones. The numerical calculations showed that the erosion processes significantly improve the results in the model with small-scale convection in the asthenosphere, forming the stress state closest to the natural one.

Stress Generation Mechanism of Elbow Pipes due to Thermal Stratification

Stress Generation Mechanism of Elbow Pipes due to Thermal Stratification

A Mathematical Model of Spatial Self-Organization in a Mechanically Active Cellular Medium

A general continual model of a medium composed of mechanically active cells is proposed. The medium is considered to be formed by three phases: cells, extracellular fluid, and an additional phase that is responsible for active interaction forces between cells and, for instance, may correspond to a system of protrusions that provide the development of active contractile forces. The deformation of the medium, which is identified with the deformation of the cell phase, consists of two components: elastic deformation of individual cells and cell rearrangements. The elastic deformation is associated with stresses in the cell phase. The spherical component of the stress tensor describes the nonlinear resistance of the cellular medium, which leads to the impossibility of its excessive compression. The constitutive equation for pressure in the cell phase is taken in the form of a nonlinear dependence on the volume cell density. The rearrangement of cells is considered as a flow controlled by stresses in the cell phase, active stresses, and fluid pressure. The tensor of active stresses is assumed to be spherical and nonlocally dependent on the cell density. Assuming that the process of biological tissue deformation is slow, we obtained a reduced model that neglects the elastic deformation of cells, compared to the inelastic deformation. A linear stability analysis of a spatially uniform steady-state solution was performed. The hydrostatic pressure of fluid is present among the parameters that are responsible for the loss of stability of the steady-state solution: an increase in it has a destabilizing effect owing to the action of the component of the interphase interaction force that is determined by the fluid pressure. The model we obtained can be used to describe the process of cavity formation in an initially homogeneous cell spheroid. The role of local and nonlocal mechanisms of active stress generation in the formation of cavity is investigated.

Stress generation in adolescence: Contributions from five-factor model (FFM) personality traits and childhood maltreatment.

Youth with depression are theorized to generate stress in their lives because of a complex interaction between their personal characteristics and their chronic environmental context. Using a moderated regression approach, we provided a novel test of this hypothesis by examining whether adolescent 5-factor model personality traits moderate the associations between early emotional, physical, and sexual maltreatment and life events experienced in the past 6 months. Participants in this cross-sectional study were 110 adolescents (M = 16.24, SD = 1.53, age range = 13-17, 74.5% female) with major depressive disorder. The relation of physical maltreatment to dependent interpersonal life events was moderated by extraversion. Among physically maltreated youth, dependent interpersonal events were positively associated with extraversion. Further, the relation of sexual maltreatment to independent events were moderated by extraversion and agreeableness. Among sexually maltreated youth, independent events were negatively associated with extraversion and positively associated with agreeableness. The observed vulnerability-risk interactions are discussed in terms of their implications for understanding the role of stress generation mechanisms in an integrated model of depression. (PsycINFO Database Record

1st International Seminar on Non-Ideal Compressible-Fluid Dynamics for Propulsion & Power

1st International Seminar on Non-Ideal Compressible-Fluid Dynamics for Propulsion & Power

The influence of near-wall density and viscosity gradients on turbulence in channel flows

The influence of near-wall density and viscosity gradients on near-wall turbulence in a channel is studied by means of direct numerical simulation of the low-Mach-number approximation of the Navier–Stokes equations. Different constitutive relations for density $\unicode[STIX]{x1D70C}$ and viscosity $\unicode[STIX]{x1D707}$ as a function of temperature are used in order to mimic a wide range of fluid behaviours and to develop a generalised framework for studying turbulence modulations in variable-property flows. Instead of scaling the velocity solely based on local density, as done for the van Driest transformation, we derive an extension of the scaling that is based on gradients of the semilocal Reynolds number, defined as $Re_{\unicode[STIX]{x1D70F}}^{\star }\equiv Re_{\unicode[STIX]{x1D70F}}\sqrt{(\overline{\unicode[STIX]{x1D70C}}/\overline{\unicode[STIX]{x1D70C}}_{w})}/(\overline{\unicode[STIX]{x1D707}}/\overline{\unicode[STIX]{x1D707}}_{w})$ (the bar and subscript $w$ denote Reynolds averaging and wall value respectively, while $Re_{\unicode[STIX]{x1D70F}}$ is the friction Reynolds number based on wall values). This extension of the van Driest transformation is able to collapse velocity profiles for flows with near-wall property gradients as a function of the semilocal wall coordinate. However, flow quantities like mixing length, turbulence anisotropy and turbulent vorticity fluctuations do not show a universal scaling very close to the wall. This is attributed to turbulence modulations, which play a crucial role in the evolution of turbulent structures and turbulence energy transfer. We therefore investigate the characteristics of streamwise velocity streaks and quasistreamwise vortices and find that, similarly to turbulence statistics, the turbulent structures are also strongly governed by $Re_{\unicode[STIX]{x1D70F}}^{\star }$ profiles and that their dependence on individual density and viscosity profiles is minor. Flows with near-wall gradients in $Re_{\unicode[STIX]{x1D70F}}^{\star }$ ($\text{d}Re_{\unicode[STIX]{x1D70F}}^{\star }/\text{d}y\neq 0$) show significant changes in inclination and tilting angles of quasistreamwise vortices. These structural changes are responsible for the observed modulation of the Reynolds stress generation mechanism and the inter-component energy transfer in flows with strong near-wall $Re_{\unicode[STIX]{x1D70F}}^{\star }$ gradients.

Dynamic Stress Analysis at Solid Electrodes

Wafer curvature and cantilever bending techniques have been used by the electrochemical community to examine stress development during electrochemical processing. Surface stress changes as low as 10−3 N/m can typically be resolved from cantilever electrodes immersed in solution and under potential control. Such resolution makes this measurement useful for examining virtually all aspects of electrochemistry; i.e., electrocapillarity, adsorption processes, underpotential deposition, electrodeposition, battery reactions, and metal hydride formation. Often these processes occur either simultaneously or in rapid succession and we are often limited to measuring the influence of the dominant process in the time-scale of the experiment. Electrochemical impedance spectroscopy (EIS) is a technique in which one measures the impedance of an electrochemical system over a range of frequencies, revealing information about the reaction mechanisms: different reaction steps will dominate at frequencies dictated by their relaxation times. Whereas traditional EIS determines the transfer function of the current in response to potential modulation, Dynamic Stress Analysis (DSA) examines the transfer function of the stress (as measured from cantilever curvature) to the same potential modulation. This will provide us with the time constants for the stress response that might enable us to directly link the stress to specific electrochemical phenomena. We first use DSA to examine the electrocapillarity (surface stress vs. charge density) behavior of (111)-textured Au and Pt cantilever electrodes in 0.1 M HClO4 electrolyte. Our measurements confirm that a direct relationship between the surface stress and the charge density exists over a wide range of frequencies and potentials. We define a general stress-charge coefficient ς = jωYsZ e that can be obtained from experimental values of the electrochemical impedance ( Ze ) and the stress admittance ( Ys ), where j and ω have their usual meaning. For both Au and Pt in the double layer region, the surface stress was found to be 180° out of phase with respect to the charge density, yielding ς  of -2.0 V and -0.7 V, respectively. These values are in agreement with first-principles calculations that appear in the literature.1, 2 In the hydrogen adsorption region, stress and charge are in phase ( ς is positive; i.e., negative charge induces compressive stress). This compressive stress response for H adsorption is contrary to charge distribution models for adsorbate-induced surface stress but supports first-principles calculations for hydrogen adsorption onto Pt (111).3, 4 We also apply DSA to electrodeposition, making use of separate stress-charge coefficients for electrocapillarity and metal deposition. Since these stress-generating mechanisms have dramatically different frequency dependency, Cu deposition is a nice demonstration that highlights the attributes of DSA; i.e., using frequency to separate the various stress contributions. 1. J.-M. Albina, C. Elsasser, J. Weissmüller, P. Gumbsch and Y. Umeno, Phys. Rev. B 85, 125118 (2012). 2. Y. Umeno, C. Elsässer, B. Meyer, P. Gumbsch, M. Nothacker, J. Weissmüller and F. Evers, EPL 78, 13001 (2007). 3. P. J. Feibelman, Phys. Rev. B 56, 2175 (1997). 4. H. Ibach, J. Vac. Sci. Technol. A12, 2240 (1994).

Critical review on the mechanisms of maturation stress generation in trees.

Trees control their posture by generating asymmetric mechanical stress around the periphery of the trunk or branches. This stress is produced in wood during the maturation of the cell wall. When the need for reaction is high, it is accompanied by strong changes in cell organization and composition called reaction wood, namely compression wood in gymnosperms and tension wood in angiosperms. The process by which stress is generated in the cell wall during its formation is not yet known, and various hypothetical mechanisms have been proposed in the literature. Here we aim at discriminating between these models. First, we summarize current knowledge about reaction wood structure, state and behaviour relevant to the understanding of maturation stress generation. Then, the mechanisms proposed in the literature are listed and discussed in order to identify which can be rejected based on their inconsistency with current knowledge at the frontier between plant science and mechanical engineering.

(Invited) Stress-Assisted Formation of Self-Organized Porous Anodic Oxides

Porous anodic oxide (PAO) films are grown by electrochemical polarization of Al, Ti, and other metals in baths that dissolve the oxide. Procedures to grow films with highly ordered and controllable arrangements of nanoscale pores have led to the extensive use of PAO films in nanofunctional devices. Experiments and calculations show that transport in the oxide occurs by electrical migration coupled with plastic flow driven by mechanical stress in the oxide, and suggest that flow may play a role in formation of self-ordered PAO (1-3). Pores initiate by a morphological instability at the oxide-solution interface when the initially formed barrier oxide reaches a critical thickness (4). Herein is reported a combined experimental and modeling investigation of the formation and self-ordering of PAO. Experiments were carried out to identify stress generation mechanisms during galvanostatic formation of Al barrier films in 0.4 M H3PO­4. Stress distributions in these films were measured by monitoring stress-induced sample curvature changes during oxide formation followed by open circuit dissolution of the films (5). Elevated compressive stress reaching several GPa was found to build up within a few nanometers of the oxide-solution interface, coinciding with high phosphorus contamination in the same layer revealed by GDOES (6). The compressive surface stress is likely due to electric field-induced phosphate incorporation. The experimentally characterized surface stress was incorporated in our anodizing model based on transport by coupled viscous flow and electrical migration (2). Morphological stability analysis of the model reveals pattern formation consistent with the well-established characteristic pore spacing to voltage relationship of PAO (7). Pore formation is governed by competition between stabilizing oxide formation at the solution interface and destabilizing flow driven by gradients of anion incorporation-induced surface stress. The model successfully predicts the critical threshold electric field and the narrow ranges of anodizing efficiency characterizing PAO formation on many metals (3,4). A compelling analogy exists between the mechanisms of PAO ordering and formation of hexagonally-ordered Marangoni patterns in thin liquid films.

Self-Organized Porous Anodic Oxide Formation: Role of Oxide Flow Driven By Surface Stress

Porous anodic oxide (PAO) films are grown by electrochemical polarization of Al, Ti, and other metals in baths that dissolve the oxide. Procedures to grow films with highly ordered and controllable arrangements of nanoscale pores have led to the extensive use of PAO films in nanofunctional devices. Experiments and calculations show that transport in the oxide occurs by electrical migration coupled with plastic flow driven by mechanical stress in the oxide, and suggest that flow may play a role in formation of self-ordered PAO (1-3). Pores initiate by a morphological instability at the oxide-solution interface when the initially formed barrier oxide reaches a critical thickness (4). Results of a combined experimental and modeling investigation of the formation and self-ordering of PAO are discussed. Experiments were carried out to identify stress generation mechanisms during galvanostatic formation of Al barrier films in 0.4 M H3PO4. Stress distributions in these films were measured by monitoring stress-induced sample curvature changes during oxide formation followed by open circuit dissolution of the films (5). Elevated compressive stress reaching several GPa was found to build up within a few nanometers of the oxide-solution interface, coinciding with high phosphorus contamination in the same layer revealed by GDOES (6). The compressive surface stress is likely due to electric field-induced phosphate incorporation. The experimentally characterized surface stress was incorporated in an anodizing model based on transport by coupled viscous flow and electrical migration (2). Morphological stability analysis of the model revealed pattern formation consistent with the characteristic pore spacing to voltage relationship of PAO (7). Pore formation is governed by competition between stabilizing oxide formation at the solution interface and destabilizing flow driven by gradients of anion incorporation-induced surface stress. The model successfully predicts the narrow ranges of anodizing efficiency characterizing PAO formation on many metals (3,4). A compelling analogy exists between the mechanisms of PAO ordering and formation of hexagonally-ordered Marangoni patterns in thin liquid films. Electrochemical impedance spectroscopy of steady-state porous anodic alumina formed in sulfuric and oxalic acid solutions are presented. It is shown that the characteristic inductive loop of impedance spectra of anodic oxide can be understood quantitatively in terms of electric field-induced homogeneous formation and annihilation of oxygen vacancies. We argue that this reaction can produce oxide displacement in the presence of sufficiently large stress gradients. The possible explanation of viscous oxide flow by such a vacancy creep mechanism is discussed.

Thermo-mechanical behaviour during encapsulation of glass in a steel vessel

Quantitative numerical simulations and qualitative evaluations are conducted to elucidate thermo-mechanical behaviour during pouring and solidification of molten glass into a stainless-steel cylindrical container. Residual stress and structural integrity in this casting/vitrification process is important because it can be used for long-term storage of high-level nuclear wastes. The predicted temperature and stress distributions in the glass and container agree well with previous measurements of the temperature histories and residual stresses. Three different thermal-stress models are developed using the finite-element method and compared. Two simple slice models were developed based on the generalized plane strain assumption as well as a detailed two-dimensional axi-symmetric model that adds elements according to the stages of pouring glass into the stainless steel container. The results reveal that mechanical interaction between the glass and the wall of the stainless steel container generates residual tensile stresses that approach the yield strength of the steel. Together, these results reveal important insights into the mechanism of stress generation in the process, the structural integrity of the product, and accuracy of the modelling-tool predictions.

Key Aspects of Adaptation Syndrome Development and Anti-Stress Effect of Mesodiencephalic Modulation

Background/Objectives: The study represents theoretical and practical justification of employing mesodiencephalic modulation as a pathogenetic method of correction within the framework of general adaptation syndrome. Methods/ Statistical Analysis: The study applied scientific analysis of literature together with structural and functional analysis within systemic approach. Based on familiarizing with factual materials, a formalizing and analytical review of theoretical data has been compiled. The data have been used for generating working hypothesis and making a comparative and deductive assessment of the assumptions. Theoretical data were generalized by scientific synthesis. The assumptions have been proven applying the results of clinical observations. Findings: Principal pathogenetic mechanisms responsible for the formation of general adaptation syndrome have been studied. The universal nature of stress development stages has been demonstrated at physiological level independently of the character of its conditioning factors. The most significant manifestations of adaptation syndrome observed in the clinical pattern of different nosological forms have been identified. With regard to the urgency of the issue of correcting systemic abnormalities caused by the stress response, general medical practice has outlined principal directions for developing pathogenetic therapy methods. The innovative approach employing mesodiencephalic modulation has been suggested for the complex treatment of systemic stress disorders. Comparative analysis established pathogenetic correlations between the key stress-generating mechanisms and therapeutical modalities of this method of treatment. Improvements/Applications: Practicability of wider introduction of mesodiencephalic modulation into the system of practical healthcare as a basic element of auxiliary pathogenetic therapy has been scientifically substantiated.

Tutorial: Understanding residual stress in polycrystalline thin films through real-time measurements and physical models

Residual stress is a long-standing issue in thin film growth. Better understanding and control of film stress would lead to enhanced performance and reduced failures. In this work, we review how thin film stress is measured and interpreted. The results are used to describe a comprehensive picture that is emerging of what controls stress evolution. Examples from multiple studies are discussed to illustrate how the stress depends on key parameters (e.g., growth rate, material type, temperature, grain size, morphology, etc.). The corresponding stress-generating mechanisms that have been proposed to explain the data are also described. To develop a fuller understanding, we consider the kinetic factors that determine how much each of these processes contributes to the overall stress under different conditions. This leads to a kinetic model that can predict the dependence of the stress on multiple parameters. The model results are compared with the experiments to show how this approach can explain many features of stress evolution.

Stress Analysis of Conical Contact Joints in the NIST 4.45 MN Deadweight Machine.

During the disassembly phase of the refurbishment of the National Institute of Standards and Technology 4.45 MN Deadweight Machine, workers confirmed previously suspected damage in certain conical contact joints within the apparatus. A finite element analysis of the contact joints is performed with the aim of understanding some of the potential origins of failure in order to prevent future damage in the machine. Parametric studies are performed using a finite element model while varying geometry, material constitutive relations, and frictional forces at the interface of the convex and concave cones. The numerical solutions treat nonlinearities originating from elastic-plastic material relations, frictional forces, and contact between the surfaces. These results provide insights into the mechanisms of stress generation in such joints, and how these stresses are influenced by different structural parameters.