Internal Tension Research Articles

Quantitative Analysis of Contractile Ability of Vascular Smooth Muscle Cells Using a Micropillar Substrate and a Laser Nanoscissor System

Vascular cell senescence and vascular aging are known to be associated with serious vascular diseases, such as arteriosclerosis and aneurysm generation. However, it is unclear how cellular dedifferentiation and senescence affects cellular contractile force which is especially important for vascular smooth muscle cells. Here we investigated the changes in the cellular contractile ability during repeatedly passage-cultivation that promotes cell dedifferentiation and senescence. Porcine aortic vascular smooth muscle cells exposed to several passage-cultivation were seeded on the polydimethylsiloxane-based elastic micropillar array substrates, and their whole cell contractile forces were preciously estimated by the deflection of the pillars. Furthermore, we dissected intracellular actin stress fibers in living cells by laser irradiation to release their pretension, observed the dynamic behavior of the dissected stress fibers, and estimated the internal tension of individual stress fibers. We found that the both of the whole cell contractile forces and the internal tension of individual stress fibers were significantly decreased in cell dedifferentiation and senescence induced by repeatedly passage-cultivation, and the decrease was more sensitive in the individual stress fibers than in the whole cell. These results indicate that cellular contractile forces are deeply involved in cellular dedifferentiation and senescence.

Addressing the Faculty Shortage Through Connections: Stories of Becoming a Nurse Educator

The current nursing faculty shortage is projected to continue. This article addresses recruitment and retention by contributing to the public stories of successful nursing faculty. Narrative inquiry was used to examine how the ways of knowing of three associate degree nurse educators evolved over time in the community college setting. The educators' early stories portrayed an internal tension that was in sharp contrast to the capability and self-confidence of an expert nurse. Stories revealed their struggle to balance empathy and care (connected knowing) with logic and objectivity (separate knowing) when handling challenging student situations. Over time, the educators developed ways of integrating connected and separate knowing, becoming constructivist knowers. The findings validate the importance of providing meaningful support for novice educators. Private spaces to promote reflection and active dialoging with a trusted mentor will assist new faculty as they work through their integration of caring verses objective knowing. [J Nurs Educ. 2020;59(10):545-550.].

Numerical investigation of fluid property effects on formation dynamics of millimeter-scale compound droplets in a co-flowing device

Effects of fluid property on the formation of millimeter-scale compound droplets in a co-flowing device were systematically investigated via a simulation method using the VOF-CSF model. The simulation shows that compound droplets are formed in three regimes, namely, dripping regime, transition regime, and jetting regime. Increasing the flow rate or viscosity of outer fluid cause flow regime to convert from dripping to jetting, and the diameter of droplet significantly decreases. However the effects of inner fluid viscosity on formation dynamics always appear various, where the breakup mode of core droplet can be significantly changed, but the influences on its geometric dimensions can be ignored. In addition, the effects of internal and external interface tension are also further discussed. Finally, a dimensionless number ξ is proposed to predict the flow regimes of compound droplets formation. The results could provide theoretical guidance for controllably preparing monodisperse millimeter-scale compound droplets with specific size.

The rationale for the combined use of osteopathic methods of correction and reflexology in the complex treatment of patients with dorsopathy at the cervico-thoracic level

Introduction. Degenerative-dystrophic changes in the spine are the most common chronic human diseases. Pronounced clinical manifestations of vertebrogenic diseases are observed during active labor activity and represent one of the most frequent causes of temporary disability. It is also known that any pain syndromes are accompanied by the development of psychovegetative disorders, which reduces the effectiveness of treatment. In recent years, there has been a reasonable increase in the interest of the medical community to the non-drug treatment methods. It is caused by the polypharmacotherapy side effects, an increased numbers of allergic reactions, problems with polypragmasia, and a low level of compliance. At the same time, the question of the possibility of various non-drug treatment methods combining is quite acute.The goal of researchis to substantiate the clinical effectiveness of the combined application of osteopathic correction and reflexotherapy in the complex treatment of patients with dorsopathy at the cervical-thoracic level.Materials and methods.A prospective controlled randomized study was conducted on the basis of the medical clinics of LLC «Family Health» (Kazan) and ANO «Center for SEB assistance» (Kazan) from April 2018 to May 2019. The study involved 52 people with dorsopathy at the cervical-thoracic level, aged from 25 to 45 years. In accordance with the exclusion criteria, 7 people dropped out of the study. The remaining patients (45 people), depending on the used treatment method, were divided by a simple randomization method using a random number generator into three groups of 15 people. The first group (main group) received osteopathic correction and reflexotherapyon the background of standard drug therapy; the second and the third groups (control groups) received only osteopathic correction orreflexotherapy, respectively, on the background of standard drug therapy. The osteopathic examination was performed for all patients regardless of the group, before and after the course of therapy, with the formation of an osteopathic conclusion.Also there was the estimation of the degree of pain syndrome severity,the asthenia, and the degree of accumulated emotional and energy charge that does not get out in a person.Results.It was found in the course of the study that the inclusion of osteopathic correction and reflexotherapy in the complex therapy of patients with dorsopathy at the cervical-thoracic level is clinically more effective than the isolated use of these methods. Such complex therapy allows to achieve a more significant reduction in the severity of the pain syndrome by VAS (p<0,05), relief of internal emotional tension (p<0,05), and increase the effectiveness of correction of dominant somatic dysfunction. Based on the obtained data, it could be assumed that reflexotherapy potentiates the effects of osteopathic correction.Conclusion.Based on the study, it can be concluded that the combination of osteopathic correction and reflexotherapy in the treatment of patients with dorsopathy at the cervical-thoracic level increases the clinical effectiveness of the standard drug therapy. At the same time, it is worth noting the potentiating effect of the combined use of two non-medicinal methods. The question of combining of various non-drug treatment methods is quite acute today, so this study will be continued.

Non-supernaturalism: Linguistic Convention, Metaphysical Claim, or Empirical Matter of Fact?

This paper examines our pre-theoretic conception of non-supernaturalism; the thesis that all that exists is natural. It is argued that we intuitively take this thesis to be a substantive, non-dogmatic, empirically justified, not merely contingent truth. However, devicing an interpretation of non-supernaturalism that captures all aspects of this intuition is difficult. Indeed, it is found that this intuition conflates the strong inferential scope of a metaphysical claim with the modest justificatory requirements of an empirical matter of fact. As such, non-supernaturalism, in its pre-theoretic form, contains an internal tension that must be navigated whenever the thesis features in systematic thinking.

Single-Molecule Stretching Shows Glycosylation Sets Tension in the Hyaluronan-Aggrecan Bottlebrush

Large bottlebrush complexes formed from the polysaccharide hyaluronan (HA) and the proteoglycan aggrecan contribute to cartilage compression resistance and are necessary for healthy joint function. A variety of mechanical forces act on these complexes in the cartilage extracellular matrix, motivating the need for a quantitative description that links their structure and mechanical response. Studies using electron microscopy have imaged the HA-aggrecan brush but require adsorption to a surface, dramatically altering the complex from its native conformation. We use magnetic tweezers force spectroscopy to measure changes in extension and mechanical response of an HA chain as aggrecan monomers bind and form a bottlebrush. This technique directly measures changes undergone by a single complex with time and under varying solution conditions. Upon addition of aggrecan, we find a large swelling effect manifests when the HA chain is under very low external tension (i.e., stretching forces less than ∼1 pN). We use models of force-extension behavior to show that repulsion between the aggrecans induces an internal tension in the HA chain. Through reference to theories of bottlebrush polymer behavior, we demonstrate that the experimental values of internal tension are consistent with a polydisperse aggrecan population, likely caused by varying degrees of glycosylation. By enzymatically deglycosylating the aggrecan, we show that aggrecan glycosylation is the structural feature that causes HA stiffening. We then construct a simple stochastic binding model to show that variable glycosylation leads to a wide distribution of internal tensions in HA, causing variations in the mechanics at much longer length scales. Our results provide a mechanistic picture of how flexibility and size of HA and aggrecan lead to the brush architecture and mechanical properties of this important component of cartilage.

How shape and flapping rate affect the distribution of fluid forces on flexible hydrofoils

Abstract

WAYS OF THE DEVELOPMENT OF SOCIAL ACTIVITY IN PRIMARY SCHOOL STUDENTS WITH HEARING IMPAIRMENT

This article discusses the importance of the development of social activity of primary school students with hearing impairments. The formation of the personality of a child with hearing impairment is slow, which is associated with certain difficulties in the development of social experience, experience in the implementation of methods of activity, experience of creative activity, in terms of emotional value to reality. Primary classes experience emotional discomfort during the period of adaptation of children with hearing impairments, are in any internal tension and stress. All children tend to have high levels of nervous, mental and physical strength. All changes in the child's behavior at this stage are associated with the process of adaptation to school. Taking into account the psychophysical characteristics of children with hearing impairment, the peculiarities of their assimilation of the material, excursions with them require more careful preparation. It includes: the definition of its purpose, objectives, content, methods; training of students: a story about the purpose, content, organization of excursions, types of work during the tour, the questions that should be found by students during the tour; thinking through forms of control of students ' understanding of the studied material; determining the content of the story, the final tour to consolidate the studied material. Much attention is paid to the interaction of children with their parents. The family plays an important role in the socialization of the child with hearing impairment; parents form self-service skills in children, a positive attitude to learning, preparing children to participate in household and socially useful work.

Pathways to gender affirmation in trans youth: A qualitative and participative study with youth and their parents.

How trans youth realize about their gender identity and come out to their significant others is under-researched and very few studies include both youth and parental perspectives. This study was developed in Switzerland, a country where families with trans youth are just beginning to break invisibility. The research protocol draws on grounded theory methodology, is participative and developed in collaboration with a local trans NGO and a pan Canadian project. We conducted 20 semi-structured interviews with 10 trans youth and their caregivers/parents (10 interview). At least three developmental pathways seem to emerge: a) the affirmed children who affirm themselves very early, (b) the silent children who spend their childhood in a state of internal tension without being able to position themselves and (c) the neutral children who become aware of their gender difference at puberty following a childhood in which gender was not problematic. In all cases puberty is a crossroads, lived painfully with significant manifestations of both social and body dysphoria. A better understanding of the process of gender development in trans children and youth will help improve our interventions to better serve young people and their families, and help them overcome the different levels of oppressions they face.

Macroscopic and microscopic analysis of the mechanical properties and adhesion force of cells using a single cell tensile test and atomic force microscopy: Remarkable differences in cell types

Many experimental techniques have been reported to provide knowledge of the mechanical behavior of cells from biomechanical viewpoints, however, it is unclear how the intercellular structural differences influence macroscopic and microscopic mechanical properties of cells. The aim of our study is to clarify the comprehensive mechanical properties and cell-substrate adhesion strength of cells, and the correlation with intracellular structure in different cell types. We developed an originally designed micro tensile tester, and performed a single cell tensile test to estimate whole cell tensile stiffness and adhesion strength of normal vascular smooth muscle cells (VSMCs) and cervical cancer HeLa cells: one half side of the specimen cell was lifted up by a glass microneedle, then stretched until the cell detached from the substrate, while force was simultaneously measured. The tensile stiffness and adhesion strength were 49 ± 10 nN/% and 870 ± 430 nN, respectively, in VSMCs (mean ± SD, n = 8), and 19 ± 17 nN/% and 320 ± 160 nN, respectively, in HeLa cells (n = 9). The difference was more definite in the surface elastic modulus map obtained by atomic force microscopy, indicating that the internal tension of the actin cytoskeleton was significantly higher in VSMCs than in HeLa cells. Structural analysis with confocal microscopy revealed that VSMCs had a significant alignment of F-actin cytoskeleton with mature focal adhesion, contrary to the randomly oriented F-actin with smaller focal adhesion of HeLa cells, indicating that structural arrangement of the actin cytoskeleton and their mechanical tension generated the differences in cell mechanical properties and adhesion forces. The finding strongly suggests that the mechanical and structural differences in each cell type are deeply involved with their physiological functions.

Barclay, Linda. Disability with Dignity: Justice, Human Rights, and Equal Status. New York: Routledge, 2018. Pp. 142. $124.00 (cloth).

Barclay, Linda. <i>Disability with Dignity: Justice, Human Rights, and Equal Status</i>. New York: Routledge, 2018. Pp. 142. $124.00 (cloth).

Level of immune complex reactions in non-psychothotic mental disorders in combatants

The level of immune complex reactions in combatants with non-psychotic mental disorders was studied. A clinical-psychopathological and clinical-biochemical examination of 95 combatants with non- psychotic mental disorders were conducted. In the clinical picture of prolonged depressive reaction, there was a decrease in mood, feelings of sadness, anxiety, anhedonia, asthenic manifestations, detachment, lack of hope, guilt of the survivor. Mixed anxiety-depressive reaction was characterized by low mood, feelings of depression, helplessness, insecurity, feelings of despair, sadness, isolated obsessive fears, doubts about the correctness of decisions and actions that are closely related to anxious thinking in relation to their assessment in the eyes of others. Post-traumatic stress disorder was manifested by low mood, anxiety, internal tension with inability to relax, danger, anxiety, flashback effects, symptoms of intrusion, asthenia, irritability, propensity to affective reactions. It was found that in the examined patients there was an increase in the concentration of circulating immune complexes, mainly due to the most pathogenic fractions of medium and low molecular weight and suppression of phagocytic activity of monocytes. Changes in immune complex reactions were most pronounced in post-traumatic stress disorder.

DEPENDENT PERSONALITY BEHAVIOR AS A PROBLEM OF MODERN PSYCHOLOGY

In the conditions of modern social and social transformations, various manifestations of addictive behavior, such as alcoholism, drug addiction, gambling, eating disorders and others, have significantly increased.The article is devoted to the analysis of the state of development of the problem of dependent behavior of the individual and the selection of the main socio-personal determinants of this phenomenon. It is shown that the specifics of modern social life of the individual, psycho-emotional loads, incomplete and individual problems and other aspects of subjective space provoke states of internal tension and discomfort, significantly increase the constant psychological pressure felt by the subject, which is realized in violations eating behavior. The purpose of the article is to consider the main approaches to dependent personality behavior In today’s world, the problem of addictive behavior is one of the most difficult and difficult for society. It is extremely important for every state to have such a community, which would consist of people who are developed, intelligent, have goals and understand how to achieve them. Summarizing the scientific material on different types of addictive behavior, we can, firstly, divide them into socially acceptable and socially unacceptable types, and secondly, chemical and non-chemical, noting that food addiction occupies an intermediate place. Analyzing the existing scientific material, we can say that addictive behavior is not only a purely medical, but also a social and cultural problem of modern society.

Stability of the viscoelastic Rayleigh–Taylor problem with internal surface tension

We investigate the stability of the Rayleigh–Taylor (RT) problem for stratified viscoelastic fluids with internal surface tension. More precisely, under the stability condition Dis(ϑ,κ)<1, we prove the existence of unique strong solution with exponential decay in time for the (stratified) viscoelastic RT (VRT) problem with proper initial data in Lagrangian coordinates. This shows that a sufficiently large elasticity coefficient or a sufficiently large surface tension coefficient has a stabilizing effect so that it can inhibit the development of (stratified) RT instability.

Identification of factors affecting competitive tension in the domestic air transport market in Turkey1

Abstract Competitive tension refers to pressure that is considered to exist among firms operating in a competitive market and that forces them to take competitive action against each other. An imaginary upper limit of competitive tension symbolizes the difference between whether to take competitive action or not. The antecedents of competitive tension are examined in this study. Within this scope, market commonality and resource similarity are the variables studied as components of competitor analysis; market concentration that provides clues for the competitive structure of competed markets; and finally, competitive asymmetry, presuming that the competition among the companies is not equal and rivals do not consider each other at the same level as competing firms, were taken as primary variables of competitive tension. In order to test whether these variables have an effect on competitive tension among airlines, airlines operating in the domestic air transport market in Turkey were examined in this study. The perceived competitive tension that was detected as a result of regression analyses was studied on three different dimensions, namely, internal tension, external tension, and total tension, and each dimension was analyzed as a different model. The findings of the study revealed that market commonality and market concentration have a significant effect on competitive tension. These effects were found to be positive for market commonality and negative for market concentration. Resource similarity and competitive asymmetry were found to have no significant effect.

Tensions between compliance, internal controls and ethics in the domain of project governance

PurposeThis study aims to investigate how the dynamics of compliance, internal controls and ethics can generate tensions in the domain of project governance. Moreover, it investigates the tensions between these constructs and the search for project success from a practice-based perspective.Design/methodology/approachA methodological approach is taken, with a case-based research carried out in a large European multinational company. Data were gathered through 21 interviews, between project managers and other key stakeholders, and documentary data from 64 projects for triangulation and critical analysis.FindingsAs a result, four patterns of tensions were identified: Tension A between compliance and project success, Tension B between internal controls and project success, Tension C between compliance and internal controls and Tension D between compliance and ethics.Research limitations/implicationsSome limitations should be acknowledged. The first, ontological, is inherent in the post-positivist perspective, accepting human subjectivity and the complexity of social reality intrinsic to research applied to the social sciences, respectively implying interpretive bias and incompleteness in the comprehension of the facts. The second limitation comes from the use of a single case study, in which singular contextual characteristics make it difficult to generalise the results.Practical implicationsThis study has implications for practice, as it highlights weaknesses that may occur in organisations owing to tensions between the elements of compliance, internal controls and ethics. This, therefore, implies ways of strengthening the consistency of project governance. The project governance domain and its tensions affect the project-success holistic view in both efficiency and effectiveness, since the elements of internal control and compliance can create tensions that favour one project success perspective to detriment of the others. Understanding the nature of tensions, their implications and the long-term holistic perspective can lead to better decisions by managers.Originality/valueThe results suggest that a formal code of ethics, a project management methodology, internal controls and a well-established training programme are not sufficient, because, in the practical context, the interaction between these elements creates tensions that impact their logical consistency lost when interacting with each other.

Prediction of the Boundary States for Thin-Walled Axisymmetric Shells Under Internal Pressure and Tension Loads

Abstract A method for calculating the ultimate true stresses arising in the walls of shells of revolution in the area of uniform plastic deformation is developed in the research. In order to derive the stability loss for the plastic deformation process the criterion of maximum load is taken as the basis, simple differential equations were solved. It has been shown analytically that the level of the boundary true stresses is much lower when the values of the principal stress ratios approach to 2 or 1/2 compared to the adjacent stress states.

Targeting Cell Contractile Forces: A Novel Minimally Invasive Treatment Strategy for Fibrosis.

Fibrosis is a complication of tendon injury where excessive scar tissue accumulates in and around the injured tissue, leading to painful and restricted joint motion. Unfortunately, fibrosis tends to recur after surgery, creating a need for alternative approaches to disrupt scar tissue. We posited a strategy founded on mechanobiological principles that collagen under tension generated by fibroblasts is resistant to degradation by collagenases. In this study, we tested the hypothesis that blebbistatin, a drug that inhibits cellular contractile forces, would increase the susceptibility of scar tissue to collagenase degradation. Decellularized tendon scaffolds (DTS) were treated with bacterial collagenase with or without external or cell-mediated internal tension. External tension producing strains of 2-4% significantly reduced collagen degradation compared with non-tensioned controls. Internal tension exerted by human fibroblasts seeded on DTS significantly reduced the area of the scaffolds compared to acellular controls and inhibited collagen degradation compared to free-floating DTS. Treatment of cell-seeded DTS with 50mM blebbistatin restored susceptibility to collagenase degradation, which was significantly greater than in untreated controls (p < 0.01). These findings suggest that therapies combining collagenases with drugs that reduce cell force generation should be considered in cases of tendon fibrosis that do not respond to physiotherapy.

Modern model of formation for post-stress disorders among military service members and veterans

The clinical phenomenology of post-stress disorders was studied in combatants. We observed 150 servicemen of the Armed Forces of Ukraine, who took a direct part in the fighting in the ATO zone, in accordance with the principles of bioethics and deontology on the basis of the National Military Medical Clinical Center «Main Military Clinical Hospital» and the Military Medical Center of the Northern Region. It is shown, that the clinical structure of post-stress disorders in combatants is represented by posttraumatic stress disorder (PTSD), acute stress response and adjustment disorders. The clinical structure of PTSD in combatants is represented by anxious (35.2 % of men and 44.2 % of women), dysphoric (33.5 % and 9.4 %), asthenic (25.4 % and 32.6 %) and somatoform (5.9 % and 13.8 %) syndrome complexes. Adjustment disorders included prolonged depressive reaction (10.1 % of men and 15.7 % of women), mixed anxiety-depressive reaction (16.5 % and 10.2 %), adjustment disorders with a predominance of disturbances of other emotions (9.8 % and 7.4 %). The major risk factors for the development of stress-related disorders in combatants were identified: prolonged participation in combat, the need to see and touch the bodies of the dead, the threat of death from sniper’s fire, the death of friends in their own eyes, the impact of harmful combat factors, family conflicts, adverse social and economic circumstances. The correlation analysis was carried out. It was found, that the severity of psychopathological symptoms is determined by the severity of combat mental trauma. High scores on the Mississippi scale are associated with prolonged mental trauma (rxy=0.64), threat of death (rxy=0.58), death of comrades (rxy=0.54), participation in close combat (rxy=0.50), the offensive (rxy=0.41), the need to touch the bodies of the dead (rxy=0.46), with the killing of opponents (rxy=0.45). There is a strong correlation of combat mental trauma with anxiety intensity (rxy=0.78), fear (rxy=0.71), sense of internal tension (rxy=0.70), disturbance of the sleep-wake cycle (rxy=0.70), incontinence of affect (rxy=0.69) and depression (rxy=0.66). Keywords: post-traumatic stress disorder, adjustment disorders, acute stress response, combat mental trauma, correlation analysis.

Combining tensile testing and microscopy to address a diverse range of questions.

Both plants and animals sense and respond to mechanical stresses that arise internally or are externally imposed. In many cases, tissues respond by changing their gene expression or their mechanical properties, which has an impact on how they develop. Many tools have been developed to measure mechanical properties and to investigate responses to mechanical stress. Here we review the state of microscope-coupled tensile testing at the single-cell and tissue scale and give a view on future opportunities for extending the technology. Uniaxial tensile testing involves quantifying the deformation of a sample when a force is applied. By varying the amount of force, the speed at which the force is applied or the length of time that it is applied for, many characteristics of the mechanical properties of the sample can be calculated. Tensile testing has been used extensively to measure the mechanical properties of whole tissues or organs. The need for higher resolution data resulted in more researchers using indentation tests to measure mechanical properties instead. Indentation tests provide information at a different scale and are not suitable for answering the same type of questions as tensile testing. Here we discuss that by coupling tensile-testing machinery with microscopes such as is the case for the Automated Confocal Micro-Extensometer (ACME) it is possible to obtain tissue-scale measurements of mechanical properties with cellular resolution. Moreover, to understand and identify the biological processes cells and tissues use to respond to mechanical stress, we need to be able to apply mechanical perturbations to plant samples while recording the induced biological changes with microscopy. LAY DESCRIPTION: Plants, like most living organisms, are sensitive to their environment. This includes mechanical stresses imposed upon them by gravity or wind. Mechanical stress can also arise from internal tissue tension, which can build up if different parts of a tissue grow at different rates. In many cases, the cells respond to mechanical stress by changing their mechanical properties, which can affect their growth and their final shape. There is thus a critical need to develop tools for measuring mechanical properties and the response to mechanical stress. Mechanical properties cannot be visualised directly but must be inferred by looking at how a tissue deforms when a force is applied or vice versa. This is more challenging when one wishes to achieve this at the cellular scale, as the forces and deformations are much smaller. There are a range of methods available that have advantages and disadvantages. Here we review some of these methods. In particular, we focus on methods that cause deformation in the main axis of the tissue. This type of test can be coupled with conventional and state-of-the-art microscopes. Coupling with microscopes increases the resolution of the tests that can be performed and facilitates the simultaneous observation of responses to the mechanical stresses.