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Introduction: Pulmonary sequestration is a rarely reported phenomenon where aberrant lung tissue exists independently from the rest of the tracheobronchial network. Complications may include hemothorax; however, there is a paucity of descriptions of this condition in the literature.Case Report: We describe a case of a pulmonary intralobar sequestration resulting in atraumatic tension hemothorax. A 73-year-old woman presented to our facility in extremis and with complaints of acute-onset flank pain. Her evaluation was notable for a large pulmonary sequestration with a presumed, moderate-sized effusion; however, initial review did not reveal an obvious underlying cause for her symptoms. Shortly after her arrival to the emergency department (ED) she experienced a cardiac arrest. On secondary review of her computed tomographic angiography, it was determined that what was previously thought to be a pleural effusion was a large hemothorax. Following this finding, a finger thoracostomy was performed, which resulted in the immediate evacuation of hemothorax. The thoracostomy was then converted into an ED thoracotomy to assess for active hemorrhage with brief return of spontaneous circulation. Prior to proceeding with emergent operative intervention, the patient’s spouse requested that all further resuscitative efforts cease, and the patient was allowed to expire. In a review of the case, it was determined that the patient suffered from cardiac arrest due to a spontaneous hemothorax secondary to a large intralobar pulmonary sequestration.Conclusion: Pulmonary intralobar sequestration can result in spontaneous hemorrhage with fatal results. Early and correct interpretation of imaging and surgical intervention are crucial in ED management.

The primary objective of this study is to precisely characterize the behavior of double bracket-to-circular Hollow Section (CHS) column joints due to combined internal forces resulting from double tensile loading in opposite directions. In order to accomplish this goal, an experimental program consisting of eight test specimens has been carried out and numerical finite element modeling has been employed for the same specimens to analyze the stresses and deformations that occur within the vicinity of bracket-to-CHS joints. A total of 15 finite element models were constructed to simulate the initial study, addressing boundary conditions and facilitating verification and results comparison. The study included an investigation of various parameters, including the spacing between brackets in the longitudinal direction, as well as the depth-to-thickness ratio of the CHS columns and adding a T-stiffener to the bracket configuration. The study determined that an increase in the diameter-to-thickness ratio of the CHS columns significantly reduced the overall strength of the joint. Furthermore, findings suggested that increasing the longitudinal spacing between brackets resulted in an increase in single-bracket joint strength and a minor reduction regarding joint strength considering the effect of line loading. Moreover, adding a T-stiffener shape for the brackets enhanced the joint strength and prevented bracket tip fracture. In addition, a distinct behavior arises when considering joints with positive eccentricity, where the forces' line of action extends beyond the circular cross-section of the CHS. In such cases, a reduction in joint strength is observed. Finally, a modification factor "A" is applied to the X-type branch plate-to-CHS strength equation presented by the AISC360-22 to account for the longitudinal spacing between brackets. [ABSTRACT FROM AUTHOR]

Using adhesively bonded joints is an effective strategy for achieving lightweight designs. However, understanding the long‐term performance of these bonded joints remains a critical concern. Creep is a time‐dependent phenomenon induced by sustained mechanical loads, which can lead to viscous strain in adhesive materials. This strain has the potential to cause cracking in bonded structures over time. This study aims to investigate the creep and post‐creep behaviors of adhesively bonded aluminum joints, focusing on two crucial parameters: creep load level and creep duration. Butt adhesive joint (BAJ) specimens were fabricated and exposed to varying creep loads and times. Subsequently, quasi‐static tensile tests were conducted to assess the residual mechanical properties. The results indicated that higher creep loads resulted in increased creep deformations at constant creep durations. Furthermore, a downward trend was observed in the residual tensile mechanical properties of BAJ specimens following creep. Specifically, higher creep load levels and longer times led to more pronounced reductions in joint strength, strain, and stiffness. These reductions in joint mechanical properties were corroborated through joint fracture surface analysis. Additionally, mathematical models were developed using response surface methodology (RSM) to predict the experimental joint residual mechanical properties under different creep loads and times. Highlights: Investigation of creep and post‐creep behaviors in adhesive joints.Higher creep load levels result in greater joint permanent deformations.Impact of higher creep load levels and durations on joint failure strength.Decreasing in the joint deformability and stiffness after creep. [ABSTRACT FROM AUTHOR]

Introduction: Cells generate mechanical forces mainly through myosin motor activity on the actin cytoskeleton. In C. elegans, actomyosin stress fibers drive contractility of the smooth muscle-like cells of the spermatheca, a distensible, tube-shaped tissue in the hermaphrodite reproductive system and the site of oocyte fertilization. Stretching of the spermathecal cells by oocyte entry triggers activation of the small GTPase Rho. In this study, we asked how forces are distributed in vivo, and explored how spermathecal tissue responds to alterations in myosin activity. Methods: In animals expressing GFP labeled actin or apical membrane complexes, we severed these structures using femtosecond laser ablation and quantified retractions. RNA interference was used to deplete key contractility regulators. Results: We show that the basal actomyosin fibers are under tension in the occupied spermatheca. Reducing actomyosin contractility by depletion of the phospholipase C-e/PLC-1 or non-muscle myosin II/NMY-1, leads to distended spermathecae occupied by one or more embryos, but does not alter tension on the basal actomyosin fibers. However, activating myosin through depletion of the Rho GAP SPV-1 increases tension on the actomyosin fibers, consistent with earlier studies showing Rho drives spermathecal contractility. On the inner surface of the spermathecal tube, tension on the apical junctions is decreased by depletion of PLC-1 and NMY-1. Surprisingly, when basal contractility is increased through SPV-1 depletion, the tension on apical junctions also decreases, with the most significant effect on the junctions aligned in perpendicular to the axis of the spermatheca. Discussion: Our results suggest that much of the tension on the basal actin fibers in the occupied spermatheca is due to the presence of the embryo. Additionally, increased tension on the outer basal surface may compress the apical side, leading to lower tensions apically. The three dimensional shape of the spermatheca plays a role in force distribution and contractility during ovulation. [ABSTRACT FROM AUTHOR]

Apical cell-cell junctions, including adherens junctions and tight junctions, adhere epithelial cells to one another and regulate selective permeability at both bicellular junctions and tricellular junctions (TCJs). Although several specialized proteins are known to localize at TCJs, it remains unclear how actomyosin-mediated tension transmission at TCJs contributes to the maintenance of junction integrity and barrier function at these sites. Here, utilizing the embryonic epithelium of gastrula-stage Xenopus laevis embryos, we define a mechanism by which the mechanosensitive protein Vinculin helps anchor the actomyosin network at TCJs, thus maintaining TCJ integrity and barrier function. Using an optogenetic approach to acutely increase junctional tension, we find that Vinculin is mechanosensitively recruited to apical junctions immediately surrounding TCJs. In Vinculin knockdown (KD) embryos, junctional actomyosin intensity is decreased and becomes disorganized at TCJs. Using fluorescence recovery after photobleaching (FRAP), we show that Vinculin KD reduces actin stability at TCJs and destabilizes Angulin-1, a key tricellular tight junction protein involved in regulating barrier function at TCJs. When Vinculin KD embryos are subjected to increased tension, TCJ integrity is not maintained, filamentous actin (F-actin) morphology at TCJs is disrupted, and breaks in the signal of the tight junction protein ZO-1 signal are detected. Finally, using a live imaging barrier assay, we detect increased barrier leaks at TCJs in Vinculin KD embryos. Together, our findings show that Vinculin-mediated actomyosin organization is required to maintain junction integrity and barrier function at TCJs and reveal new information about the interplay between adhesion and barrier function at TCJs. [Display omitted] • Vinculin is mechanosensitively recruited to tricellular junctions • Vinculin's actin-binding function is needed for tricellular actomyosin organization • Vinculin reinforces tricellular junction integrity in response to increased tension • Vinculin is required to maintain barrier function at tricellular junctions Epithelial tricellular junctions are vulnerable to disruption. Here, van den Goor et al. reveal that Vinculin is mechanosensitively recruited to vertebrate tricellular junctions, where it regulates actomyosin organization and barrier function. Vinculin reinforces tricellular junction integrity when epithelia experience increased mechanical force. [ABSTRACT FROM AUTHOR]

Objective: Midpalatal expansion (MPE) is routinely employed to treat transverse maxillary arch deficiency. Neutrophils are indispensable for recruiting bone marrow stromal cells (BMSCs) at the initial stage of bone regeneration. This study aimed to explore whether neutrophils participate in MPE and how they function during bone formation under mechanical stretching. Materials and Methods: The presence and phenotype of neutrophils in the midpalatal suture during expansion were detected by flow cytometry and immunofluorescence staining. The possible mechanism of neutrophil recruitment and polarization was explored in vitro by exposing vascular endothelial cells (VECs) to cyclic tensile strain. Results: The number of neutrophils in the distracted suture peaked on Day 3, and N2‐type neutrophils significantly increased on Day 5 after force application. The depletion of circulatory neutrophils reduced bone volume by 43.6% after 7‐day expansion. The stretched VECs recruited neutrophils via a CXCR2 mechanism in vitro, which then promoted BMSC osteogenic differentiation through the VEGFA/VEGFR2 axis. Consistently, these neutrophils showed higher expression of canonical N2 phenotype genes, including CD206 and Arg1. Conclusions: These results suggested that neutrophils participated in early bone formation during MPE. Based on these findings, we propose that stretched VECs recruited and polarized neutrophils, which, in turn, induced BMSC osteogenic differentiation. [ABSTRACT FROM AUTHOR]

External root resorption is a main side effect of orthodontic treatment and is more likely to occur on the pression side than the tension side. To explore the potential protective mechanisms on the tension side, this study investigated the influence of mechanical tension on cementoblast mineralization and elucidated the role of autophagy in mediating this process. Mechanical tension was applied to cementoblasts using iStrain. The expression of mineralization-related and autophagy-related markers was detected by qRT-PCR, Western blot analysis, and immunofluorescence staining. RNA sequencing identified key regulators. Immunohistochemical staining assessed related markers expression in in vivo experiments. Applying tension to cementoblasts increased mineralization-related gene expression in a force-dependent and time-dependent manner. The immunohistochemical staining result of in vivo experiments supported these findings, demonstrating elevated expression of mineralization markers under tension. Mechanical tension also enhanced autophagic activity in cementoblasts, which was demonstrated by the results of qRT-PCR, Western blot analysis, immunofluorescence staining, and in vivo experiments. Suppression of autophagy with chloroquine attenuated the mineralization of cementoblasts induced by tension stimulus. RNA-seq identified Postn as a key regulator, and the knockdown of Postn impaired the mechanical tension-promoted mineralization of cementoblasts. This study proposed the tension-induced promotion in mineralization of cementoblasts and emphasized the mediating role of autophagy in this process. Postn, a mediator connecting autophagy and mineralization, was identified as a key regulator. These discoveries helped elucidate orthodontic-related microprocesses on tooth roots and offer potential targets for therapeutic interventions to prevent and restore external root resorption clinically. [ABSTRACT FROM AUTHOR]

Background: Leash pulling is a commonly reported problem behavior for dog owners, as a result, a variety of leash equipment types are offered to mitigate pulling force. We were particularly interested in prong collars as their inherently aversive design has made their use a subject of debate. Though banned in certain countries and widely available in others, to date, there is no research comparing them to other leash walking equipment. Methods: We compared four types of leash walking equipment: a martingale (flat collar as baseline measure), a front-connection harness, a polymer prong-style collar (Starmark), and a standard metal prong collar. Twenty-three dogs were walked on all four types of equipment for 5-min each. Equipment was attached to a leash which was connected to a battery-powered strain gauge to measure the dog's pulling force. All walks were video recorded for behavior analysis. Results: There were statistically significant differences among the leash equipment types in pulling impulse (Newtons × seconds), (χ2(2) = 30.6, p < 0.001). Post-hoc analysis revealed significant differences in impulse between the martingale and the other equipment: harness (Z = −3.69, p < 0.001), Starmark collar (Z = −3.62, p < 0.001) and prong collar (Z = −3.92, p < 0.001). No other differences among equipment types were significant. Fifteen behaviors were examined as welfare indicators but only three: looking at the handler, lip licking, and sniffing occurred across all dogs and all walks. There was a statistically significant difference in frequency of lip licking behavior across the four types of leash-equipment (χ2(2) = 8.17, p = 0.04) and post-hoc analysis showed a difference between the martingale and the harness (Z = −2.65, p = 0.008). While our research did not provide any clear evidence of poorer welfare due to equipment type, we caution the generalizability of these findings and recommend further assessment of these items of leash-walking equipment in real-life scenarios. [ABSTRACT FROM AUTHOR]

A novel material testing concept is developed in order to provide tensile and compressive properties within a single mechanical test. A new specimen geometry is designed for testing in a universal testing machine. Under tensile load, both a homogeneous tensile stress condition as well as a homogeneous compressive stress condition occur in the specimen. Measurements accompanying the experimental test with digital image correlation provide tensile and compressive Poisson's ratio as well as tensile modulus. These properties are input parameters for subsequent finite element simulations. The compressive modulus is determined by iteratively adjusting finite element simulations in order to couple experimental and simulated results. For validating the concept, experimental tests are carried out on polyoxymethylene. While the tensile Poisson's ratio of the new concept shows the best agreement with the reference value, the compressive modulus is approximately 15% higher. Further work should focus on an appropriate material model in order to reduce the deviation. [ABSTRACT FROM AUTHOR]

When oil palm lumber is considered for load-bearing products such as glued laminated timber (GLT), defined strength and stiffness values are required. In this investigation, combined GLT from oil palm wood is tested in compression parallel and perpendicular and glulam lamellas in tension parallel to the vascular bundles. Strength and Young´s modulus in compression and tension parallel increase with the density by power law relationship. In contrast to dicotyle-dons, the strength in construction size exceeds that of small, defect-free test specimens (compression strength perpendicular), are in the same range (tensile and bending strength parallel) or only a little below (compression strength parallel). The specimen size does not influence the strength. The ratio of fc,0 : fm : ft,0 is 1.2 : 0.8 ... 1.7 ... 2.6 : 1 and fc,0 : fc,90 = 2.7 ... 13.0 ... 32.6 : 1 for ρ = 200 ... 400 ... 600 kg/m³; the ratio of Ec,0 : Em : Et,0 is 1.2 : 1.3 : 1 for ρ = 400 kg/m³. Ashby´s performance indices for minimum weight design rise with the density; the strength-density performance indices are comparable or only slightly lower than that for structural size softwood, whereas the modulus-density performance indices are much lower. The challenge in use of oil palm wood for load-bearing construction products is the low stiffness. [ABSTRACT FROM AUTHOR]

Copyright of GeSec: Revista de Gestao e Secretariado is the property of Sindicato das Secretarias e Secretarios do Estado de Sao Paulo (SINSESP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nonwoven filter media are used in many industrial applications due to their high filtration efficiency and great variety of compositions and structures which can be produced by different processes. During filter operation in the separation process, the fluid flow exerts forces on the filter medium which leads to its deformation, and in extreme cases damage. In order to design or select a reliable filter medium for a given application, it is essential to have a comprehensive understanding of the mechanical properties of the nonwoven material. In general, the properties of the filter material are influenced by temperature and can be changed during loading due to irreversible deformation, fatigue, and aging processes. In order to gain a deeper comprehension, the presented study examines the influence of temperature and repeated tensile stress on the filter medium properties. The focus is on fuel and oil filters employed in automotive applications. The characteristic properties of the samples, including thickness, porosity, and permeability as well as Young's modulus and Poisson's number, are measured. Young's modulus is determined for both new and aged samples. In addition, the viscoelastic behavior is investigated via a dynamic mechanical thermal analysis. The results demonstrate a significant dependence of mechanical properties on the material composition and the aging effects. [ABSTRACT FROM AUTHOR]

Background: This study aims to investigate the causal relationship between erectile dysfunction (ED) and psychological states including worry, tension, insomnia, sensitivity to environmental stress and adversity (SESA). Method: This study the used two‐sample bi‐directional Mendelian randomization (MR) method. The study data was obtained from a pooled dataset of genome‐wide association studies (GWAS). The bi‐directional MR analysis was performed using inverse variance weighting, weighted median method, and MR‐Egger regression analysis to assess the causality between ED and psychological states including worry, tension, insomnia, SESA in terms of odd ratios (OR). The study tested for heterogeneity using the Cochran Q method and for multiple validity using the MR‐Egger and MR‐PRESSO methods. Results: In forward MR analysis correlating worry, tension, insomnia, and SESA as exposures, no causal relationship was found between worry or tension and ED (p < 0.05). However, insomnia (p = 0.001, OR = 3.441, 95%CI = 1.593–7.435) and SESA (p = 0.004, OR = 1.804, 95%CI = 1.203–2.701) were found to have a significant causal effect on ED risk. The reverse MR analysis with ED as the exposure did not show any significant correlation (all p > 0.05). Conclusion: Individuals with insomnia and SESA are at higher risk for developing ED. Clinical evaluation should be more thorough for these individuals. Insomnia can be treated simultaneously with psychological counseling to reduce the risk of ED. In addition, there is no evidence to suggest that worry and tension increase the risk of ED. [ABSTRACT FROM AUTHOR]

Centrality measures are scalar values given to each vertex in the graph to quantify its importance based on an assumption. Stress and tension are the two centrality measures which depends on shortest paths. Stress of a vertex v is the number of shortest paths passing through vertex v whereas, tension on an edge e is the number of shortest paths passing through the edge e. In this paper, authors obtain formulae for the evaluation of stress and tension of certain graphs and graph operations with diameter less than or equal to two. Also obtain tension of some wheel related graphs such as gear graph, helm graph, flower graph and sunflower graph. [ABSTRACT FROM AUTHOR]

We examined the integrity of flash-frozen and cryo-sectioned cardiac muscle preparations (introduced by Feng and Jin, 2020) by assessing tension transients in response to sinusoidal length changes at varying frequencies (1–100 Hz) at 25 °C. Using 70-μm-thick sections, we isolated fiber preparations to study cross-bridge (CB) kinetics: preparations were activated by saturating Ca2+ as well as varying concentrations of ATP and phosphate (Pi). Our results showed that, compared to ordinary skinned fibers, in-series stiffness decreased to 1/2, which resulted in a decrease of isometric tension to 62%, but CB kinetics and Ca2+ sensitivity were little affected. The pCa study demonstrated that the rate constant of the force generation step (2πb) is proportionate to [Ca2+] at < 5 μM, suggesting that the activation mechanism can be described by a simple second order reaction. We also found that tension, stiffness, and magnitude parameters are related to [Ca2+] by the Hill equation, with a cooperativity coefficient of 4–5, which is consistent with the fact that Ca2+ activation mechanisms involve cooperative multimolecular interactions. Our results support the long-held hypothesis that Process C (Phase 2) represents the CB detachment step, and Process B (Phase 3) represents the force generation step. Moreover, we discovered that constant H may represent the work-performing step in cardiac preparations. Our experiments demonstrate excellent CB kinetics with two well-defined exponentials that can be more distinguished than those found using ordinary skinned fibers. Flash-frozen and cryo-sectioned preparations are especially suitable for multi-institutional collaborations nationally and internationally because of their ease of transportation. [ABSTRACT FROM AUTHOR]

Abstract The primary objective of this study is to precisely characterize the behavior of double bracket-to-circular Hollow Section (CHS) column joints due to combined internal forces resulting from double tensile loading in opposite directions. In order to accomplish this goal, an experimental program consisting of eight test specimens has been carried out and numerical finite element modeling has been employed for the same specimens to analyze the stresses and deformations that occur within the vicinity of bracket-to-CHS joints. A total of 15 finite element models were constructed to simulate the initial study, addressing boundary conditions and facilitating verification and results comparison. The study included an investigation of various parameters, including the spacing between brackets in the longitudinal direction, as well as the depth-to-thickness ratio of the CHS columns and adding a T-stiffener to the bracket configuration. The study determined that an increase in the diameter-to-thickness ratio of the CHS columns significantly reduced the overall strength of the joint. Furthermore, findings suggested that increasing the longitudinal spacing between brackets resulted in an increase in single-bracket joint strength and a minor reduction regarding joint strength considering the effect of line loading. Moreover, adding a T-stiffener shape for the brackets enhanced the joint strength and prevented bracket tip fracture. In addition, a distinct behavior arises when considering joints with positive eccentricity, where the forces’ line of action extends beyond the circular cross-section of the CHS. In such cases, a reduction in joint strength is observed. Finally, a modification factor “A” is applied to the X-type branch plate-to-CHS strength equation presented by the AISC360-22 to account for the longitudinal spacing between brackets.

Background/purpose: External root resorption is a main side effect of orthodontic treatment and is more likely to occur on the pression side than the tension side. To explore the potential protective mechanisms on the tension side, this study investigated the influence of mechanical tension on cementoblast mineralization and elucidated the role of autophagy in mediating this process. Materials and methods: Mechanical tension was applied to cementoblasts using iStrain. The expression of mineralization-related and autophagy-related markers was detected by qRT-PCR, Western blot analysis, and immunofluorescence staining. RNA sequencing identified key regulators. Immunohistochemical staining assessed related markers expression in in vivo experiments. Results: Applying tension to cementoblasts increased mineralization-related gene expression in a force-dependent and time-dependent manner. The immunohistochemical staining result of in vivo experiments supported these findings, demonstrating elevated expression of mineralization markers under tension. Mechanical tension also enhanced autophagic activity in cementoblasts, which was demonstrated by the results of qRT-PCR, Western blot analysis, immunofluorescence staining, and in vivo experiments. Suppression of autophagy with chloroquine attenuated the mineralization of cementoblasts induced by tension stimulus. RNA-seq identified Postn as a key regulator, and the knockdown of Postn impaired the mechanical tension-promoted mineralization of cementoblasts. Conclusion: This study proposed the tension-induced promotion in mineralization of cementoblasts and emphasized the mediating role of autophagy in this process. Postn, a mediator connecting autophagy and mineralization, was identified as a key regulator. These discoveries helped elucidate orthodontic-related microprocesses on tooth roots and offer potential targets for therapeutic interventions to prevent and restore external root resorption clinically.

The article presents the results of studies of profile joints of mechanisms and machines for rigidity and strength. The device is based on the use of fixed and movable profile connections designed to transmit torque. Profile joints with a guaranteed gap are considered, made on the basis of an equiaxial contour of the P3, P5 type and a curved contour of the PC4 type, which have received the most widespread introduction in the nodes of metal-cutting machines and other machines manufactured in Russia, as well as Hungary, Germany and the DPRK. Using a well-known technique designed to assess the stress-strain state (VAT) of the parts of profile joints, calculations are performed according to the criteria of operability for strength and stiffness of hubs (bushings) with different wall thicknesses. The analysis of the results of the calculation of strength and stiffness is carried out using the example of the P3 profile. When stretching the hub from the action of spacer forces, the geometric shape, the nominal size of the covered part, the wall thickness of the covering part, as well as the magnitude of the external load transmitted by the connection in static are taken into account. The permissible values of the thickness of the walls of the hub (bushings) of the joint are determined to ensure the rigidity of the hub under tension from the action of external loads. As a result of the research, the influence of the thickness of the hub walls for the studied shapes of the joint parts on the values of the transmitted torque is established. For example, a change in the thickness of the hub wall from 15 to 3 mm for a normal range of shaft mounting diameters causes the sleeve to stretch radially up to 50 microns in the range of transmitted torques from 5 to 600 Nm.

Introduction. Plastic deformation and electric current, acting separately, usually have opposite effects on the deformation behavior and flow stresses in electrically conductive materials. In the case of the combined action of plastic deformation and applied electric current, the result is not pre predictable. The study of the synergistic effect of deformation and electric current can be used for metal forming. Aim of the Study. The study is aimed at demonstrating the existence of impulse current threshold parameters at which the athermal electroplastic effect manifests itself in various materials. Materials and Methods. Tensile tests were performed at various current modes, which exclude the increased contribution of the thermal effect to the reduction of flow stresses – current density and duty cycle. The fractographic features of the fracture surface were studied using raster scanning microscopy. There were found the threshold values of current parameters at which stress jumps associated with the electroplastic effect occur. Results. The influence of the density and duty cycle of the impulse current on the manifestation of the electroplastic effect is shown. Both parameters have threshold values, above which the electroplastic effect becomes observable (at density j jкр ) or athermal (at duty cycle Q Qкр). All types of tension are accompanied by a viscous fracture and void formation, which is most intensively formed, when current is injected. Discussion and Conclusion. In alloys with low electrical resistance, the threshold impulse current density corresponding to the occurrence of the electroplastic effect is higher than in alloys with high electrical resistance. Increasing the duty cycle of the impulse current reduces the temperature of the deformed sample that allows considering the electroplastic effect as athermal.

The presented work presents the results of a study on the effect of small amounts of phthalic acid additives on dendrite formation in low-density polyethene (LDPE). Based on the results obtained, it is shown that the dendrite resistance of LDPE, as expected, increases with the introduction of 0.05 wt% phthalic acid. The established increase in dendrite resistance of LDPE with the introduction of phthalic acid can primarily be explained based on a decrease in inhomogeneities in the form of air pores as a result of accelerated structure formation and the emergence of a more homogeneous supramolecular structure. It was revealed that an increase in dendrite resistance correlates with an improvement in the dielectric characteristics of the composition. The influence of mechanical load on the development of dendrites in polymer dielectrics has been studied. As a result of studying the growth of dendrites in LDPE samples and its optimal composition subjected to unilateral stretching, it was found that under the influence of mechanical tensile stresses, the shape of the surface delimiting tree-like shoots changes, this surface is flattened in the direction of stretching. It has been shown that the rate of dendrite growth increases as mechanical tensile forces increase.

Peripheral nerve injuries that are not acutely repaired may lead to a nerve gap because of the surrounding zone of injury and elastic recoil of nerve tissue after laceration. This can result in tension across the repair site during primary neurorrhaphy. Decades of basic science literature using in vivo models consistently demonstrate a relationship between increasing strain at a neurorrhaphy site and compromised microvascular blood flow. Clinical and laboratory data suggest tension-free repairs are associated with optimal outcomes; in the setting of a short segmental nerve gap, data suggest primary repair may continue to yield good functional results. In the case of high strain, nerve grafting or other methods should be considered given poor results of primary repairs performed under high tension because of local ischemia and fibrosis on a cellular level.

The problem of stability of a cylindrical shell with various modules on a viscoelastic base is investigated. It is assumed that the shell of a circular cross section is subjected to force and loses stability in an axisymmetric form. It is believed that one end of the shell remains motionless, while the other changes its location (moves) at a certain speed. It is assumed that the transverse displacement is greater than the longitudinal one. When solving the problem, the resistance of the external environment was taken into account, and it was also read that the cylindrical shell was made of a material of different modularity. Relationship equations are obtained between the critical force and the characteristic parameters for a cylindrical shell located on a base, characterized, in turn, as a viscoelastic base and the Pasternak model. From the equations obtained and the results presented, it can be seen that serious errors are allowed if, when solving stability issues, the resistance of the external environment and different modularity are not taken into account. The calculation results show that the value of the critical force in the case under consideration differs significantly from the values corresponding to classical problems, and depends on the parameters characterizing the base resistance. The results obtained can be used in calculations of multi-modulus cylindrical shells for strength, stability, and frequency-amplitude characteristics, taking into account the resistance of the external environment.

Pultruded fiber reinforced polymer composites used in civil, power, and offshore/marine applications use fillers as resin extenders and for process efficiency. Although the primary use of fillers is in the form of an extender and processing aid, the appropriate selection of filler can result in enhancing mechanical performance characteristics, durability, and multifunctionality. This is of special interest in structural and high voltage applications where the previous use of specific fillers has been at levels that are too low to provide these enhancements. This study investigates the use of montmorillonite organoclay fillers of three different particle sizes as substitutes for conventional CaCO3 fillers with the intent of enhancing mechanical performance and hygrothermal durability. The study investigates moisture uptake and kinetics and reveals that uptake is well described by a two-stage process that incorporates both a diffusion dominated initial phase and a second slower phase representing relaxation and deterioration. The incorporation of the organoclay particles substantially decreases uptake levels in comparison to the use of CaCO3 fillers while also enhancing stage I, diffusion, dominated stability, with the use of the 1.5 mm organoclay fillers showing as much as a 41.5% reduction in peak uptake as compared to the CaCO3 fillers at the same 20% loading level (by weight of resin). The mechanical performance was characterized using tension, flexure, and short beam shear tests. The organoclay fillers showed a significant improvement in each, albeit with differences due to particle size. Overall, the best performance after exposure to four different temperatures of immersion in deionized water was shown by the 4.8 mm organoclay filler-based E-glass/vinylester composite system, which was the only one to have less than a 50% deterioration over all characteristics after immersion for a year in deionized water at the highest temperature investigated (70 °C). The fillers not only enhance resistance to uptake but also increase tortuosity in the path, thereby decreasing the overall effect of uptake. The observations demonstrate that the use of the exfoliated organoclay particles with intercalation, which have been previously used in very low amounts, and which are known to be beneficial in relation to enhanced thermal stability, flame retardancy, and decreased flammability, provide enhanced mechanical characteristics, decreased moisture uptake, and increased hygrothermal durability when used at particle loading levels comparable to those of conventional fillers, suggesting that these novel systems could be considered for critical structural applications. [ABSTRACT FROM AUTHOR]

Copyright of Revista Latinoamericana de Estudios sobre Cuerpos, Emociones y Sociedad is the property of Revista Latinoamericana de Estudios sobre Cuerpos, Emociones y Sociedad and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This research explores the results of the most common laboratory based indirect tension strength methods over the range of UCS strengths 0.1 MPa (cemented paste backfill) to 100 MPa (concrete). The accuracy of each of the methods is considered through a comparison with direct strength measurements completed on the same material. The results of 241 individual tests suggest that the use of indirect tension methods to determine tension strength for all geo-material strength ranges may provide misleading results unless a correction-factor is applied. Correction factors that relate splitting and flexure results to direct tension results are provided. The correction factors are based on the characteristic UCS of the material. A comparison of the traditional empirical relationship to derive tension from UCS is presented and an updated relationship is proposed that is relevant over the UCS strength range 0.1–100 MPa. [ABSTRACT FROM AUTHOR]

With the addition of electrically conductive steel or carbon fibers, Ultra-High-Performance Concrete (UHPC) possesses an intrinsic self-sensing capability. This opens up the possibility of combining the resilience and sustainability of UHPC with the development of self-sensing solutions for structural applications. In this study, the self-sensing behaviour of a proprietary nano-engineered UHPC material subjected to tension was investigated. To assess the self-sensing performance of the material, bulk resistivity measurements were used on direct tension and pure flexure tests, while a novel wireless approach that operates on was used on out-of-plane bending tests. The wireless approach used alternate current (AC) measurements while the bulk resistivity methods were performed through direct current (DC) and the four-probe method. In both methods, the fractional change in resistance was correlated to the state of deformation. The disposition of the actual strain field was evaluated using Digital Image Correlation (DIC). It was found that in the case of direct tension and pure flexure, the fractional change of resistance was initially decreased up to the onset of strain localization, while it gradually increased in the post-peak range, where the separation of the localized crack gradually increased. In the case of the wireless approach using AC, the onset of cracking was successfully predicted with an abrupt increase in resistivity. The wireless strain-sensing approach also captured the Poisson's effect due to the loading. [ABSTRACT FROM AUTHOR]

FFF (fused filament fabrication) is a type of 3D printing that utilizes filament for part creation. This study proposes using by-products or waste to replace part of the plastic in FFF filament, reducing environmental impact. The aim is to maintain a simple manufacturing process involving extrusion on a single-screw desktop machine followed by printing. The plastic matrix comprises polylactic acid (PLA) and polyethylene glycol (PETG), with added powdered by-products: seashells, car glass and mill scale (metal). Additives will be incorporated at 10% and 20% by weight, with two grain sizes: up to 0.09 mm and up to 0.018 mm. Mechanical tests (tensile, flexural and hardness) and thermal characterization tests will be conducted. Findings suggest adding 10%w powder of any variety to PETG increases tensile strength up to 48%, with metal powder (mill scale) showing the highest enhancement, even at 20%w, resulting in a 41% increase. Conversely, adding powder to PLA worsens mechanical properties without stiffening the material; instead, the elastic modulus decreases. Metal grain size has minimal impact, with grain sizes lower than 0.09 mm optimal for PLA. Thermal conductivity in polymers blended with powder additives is lower than in virgin polymers, likely due to air void formation, supported by density and microscopic evaluations. This research underscores the potential of utilizing waste materials with a simple FFF filament production to enhance sustainability in 3D printing practices. [ABSTRACT FROM AUTHOR]

Grounded in a paradox perspective, this article investigates the tensions of fluid informal organizing and, using a practice theory lens, explains how micro-level communicative practices deal with those tensions. Through interview and observational data, the study illustrates how tensions of integration/separation, inclusion/exclusion, and autonomy/control intersect with organizational efforts to maintain a public recreation space and are dealt with via social, material, and performative practices of worth signaling, consensus by validation, and social/material nudging. Findings add to theory on organizing tensions by moving beyond discursive and strategic responses to tension, which often focus on altering the meaning of tensions or rely upon conventional organizing elements, to emphasize how materiality and mundane practices are consequential for theory building on tension response. [ABSTRACT FROM AUTHOR]

The presented work presents the results of a study on the effect of small amounts of phthalic acid additives on dendrite formation in low-density polyethene (LDPE). Based on the results obtained, it is shown that the dendrite resistance of LDPE, as expected, increases with the introduction of 0.05 wt% phthalic acid. The established increase in dendrite resistance of LDPE with the introduction of phthalic acid can primarily be explained based on a decrease in inhomogeneities in the form of air pores as a result of accelerated structure formation and the emergence of a more homogeneous supramolecular structure. It was revealed that an increase in dendrite resistance correlates with an improvement in the dielectric characteristics of the composition. The influence of mechanical load on the development of dendrites in polymer dielectrics has been studied. As a result of studying the growth of dendrites in LDPE samples and its optimal composition subjected to unilateral stretching, it was found that under the influence of mechanical tensile stresses, the shape of the surface delimiting tree-like shoots changes, this surface is flattened in the direction of stretching. It has been shown that the rate of dendrite growth increases as mechanical tensile forces increase. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the L.N. Gumilyov Eurasian National University. Technical science & Technology series is the property of L.N. Gumilyov Eurasian National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Dirasat: Educational Sciences is the property of University of Jordan and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Social enterprises are organisations comprised of two conflicting logics: social and commercial. However, simultaneous commitment to both logics often leads to tensions, making social enterprises fragile organisations at the risk of mission drift. The extant literature on hybridity highlights two important overall strategies – integration and differentiation - for managing tensions. However, integration or differentiation alone can create additional problems, which is especially true in the case of differentiation, creating a situation comparable to black and white, with a salient faultline and heated conflicts. In this inductive qualitative case study, responding to the recent call in the literature on how to mitigate such challenges, we will show that social enterprises could employ two strategies called people circulation and weaving warp and weft to achieve a reintegrated, embedded situation referred as yin and yang with a mitigated faultline and lessened tensions. [ABSTRACT FROM AUTHOR]

Objectives: Current research suggests static stretch-induced maximal strength increases and muscle hypertrophy with potential to substitute resistance-training routines. However, most studies investigated the plantar flexors. This study explored the effects of a static stretching program on maximal strength, hypertrophy and flexibility of the pectoralis major and compared the effects with those of traditional resistance training. Methods: Eighty-one (81) active participants were allocated to either a static stretching, strength-training or control group. Pectoralis stretching was applied 15 min/day, 4 days per week for 8 weeks, while resistance training trained 3 days per week, 5 × 12 repetitions. Results: There was an increase in all parameters (strength: p < 0.001, ƞ2 = 0.313, muscle thickness: p < 0.001, ƞ2 = 0.157–0.264, flexibility: p < 0.001, ƞ2 = 0.316) and a time*group interaction (strength: p = 0.001, ƞ2 = 0.154, muscle thickness: p = 0.008–0.001, ƞ2 = 0.117–0.173, flexibility: p < 0.001, ƞ2 = 0.267). Post-hoc testing showed no difference between both intervention groups regarding maximal strength and muscle thickness (p = 0.905–0.983, d = 0.036–0.087), while flexibility increased in the stretching group (p = 0.001, d = 0.789). Conclusion: Stretching showed increases in maximal strength and hypertrophy, which were comparable with commonly used resistance training. Based on current literature, the influence of mechanical tension as the underlying mechanism is discussed. Furthermore, as equipment and comparatively long stretching durations are requested to induce meaningful strength increases in recreationally active participants, practical application seems limited to special circumstances. [ABSTRACT FROM AUTHOR]

In the engineering approach, the calculation of stress-strain values is crucial for determining the mechanical properties of materials. It is known that stress values could be calculated using the cross-section area, the moment of inertia of the material, and even strain values. However, the experimental determination of strain values is somewhat more complicated. In strain calculation, a video- extensometer and strain gauge are generally utilized. The goal of this study is to determine the strain values of the steel material in the linear region with experimental, theoretical and numerical approaches and to examine the suitability of the use of strain gauges for bending, torsion and tensile tests. Three sets (Tension, Torsion and Bending) were prepared in the experimental approach, and strain values were obtained for each experimental set-up. Furthermore, geometric models similar to experimental design were applied to ANSYS finite element program in numerical analyses. Additionally, the strain values were determined theoretically using the full bridge approach in Wheatstone Bridge Theorem. It is thought that assessing the use of the Wheatstone bridge, examining, and comparing the theoretical approaches of different loadings, modelling the appropriate experimental methods in the finite element program, and getting results, and finally interpreting these results, make a valuable contribution to the literature. The strain values were compared. Accordingly, the mean error values between theoretical and numerical for tensile, bending and torsion tests are 5.17%, 4.23% and 6.26%, respectively. The mean error values between the theoretical-experimental results of the same tests were 7.08%, 3.48% and 4.89%, respectively. Consequently, it was seen that experimental, numerical, and theoretical approaches gave more convergence points for each test. [ABSTRACT FROM AUTHOR]

Wire rope is a complex structure made by twisting wires of various sizes in the longitudinal direction. It is used to support or move engineering structures and is subject to various tensions. Dynamic properties are important parameters to evaluate the resistance to bending deformation and vibration reduction of various structures. They are affected by the magnitude of tension. In this study, an experimental method for measuring the frequency-dependent characteristics of wire rope under tension is proposed. The study analyzed flexural wave propagation employing a vibration transfer function. Experimental results showed that the transfer function of wire rope under tension is affected by tension and bending stiffness. The Newton–Raphson method was employed to numerically measure wavenumbers of the wire rope. The bending stiffness and loss factor were determined from the wavenumbers. Changes in the bending stiffness and loss factor as the tension increased were explained by the dynamic behavior of the structure under tension. As the tension increased, the bending stiffness increased, and the loss factor decreased. Hysteresis analysis indicated that the energy dissipation of wire rope is greater than that of a steel beam due to the friction between the wires. Statistical analysis confirmed a significant correlation between dynamic characteristics and tension in wire rope. [ABSTRACT FROM AUTHOR]

Organizational unlearning plays a vital role in facilitating new product development (NPD); however, the microprocesses of unlearning (i.e., how to unlearn) remain unclear. We aim to open this black box by investigating how two important dimensions—beliefs and routines—change during the unlearning process, using a longitudinal case study approach. Through a case study of Geely Auto, we identified specific cognitive and behavioral practices in the unlearning process and categorized them into three stages according to their time of occurrence and consequences. By adopting a tension lens, we demonstrate that unlearning involves three sequential steps: tension imposition, integration, and splitting. Our case study demonstrates that unlearning NPD processes involves a complex interweaving of changes in beliefs and routines. We advance the literature on learning by revealing the microprocesses that underlie organizational unlearning, and we open a broad avenue for future research to explore the microfoundations of organizational unlearning. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the impact of repeated exposure to hyperbaric hydrogen (90 MPa; 30 °C) and pressure release on the microstructure and mechanical behavior of PA11. Samples were analyzed after 1, 2, 5 and 10 cycles, by SAXS, WAXS, DMA, DSC, and a series of mechanical tests with variable triaxiality ratio. The most visible change in the residual state after desorption was a stiffening of the amorphous phase. It mainly originated from the first cycle, especially the first pressurization. The crystalline phase was slightly affected and no evidence of nano-voiding was brought in the residual state up to 10 cycles. Similar analyses were conducted during the first cycle's desorption transient. They showed a reversible plasticizing effect and a trend of nano-voiding vanishing after desorption but might promote damage upon further triaxial loading.

Background Leash pulling is a commonly reported problem behavior for dog owners, as a result, a variety of leash equipment types are offered to mitigate pulling force. We were particularly interested in prong collars as their inherently aversive design has made their use a subject of debate. Though banned in certain countries and widely available in others, to date, there is no research comparing them to other leash walking equipment. Methods We compared four types of leash walking equipment: a martingale (flat collar as baseline measure), a front-connection harness, a polymer prong-style collar (Starmark), and a standard metal prong collar. Twenty-three dogs were walked on all four types of equipment for 5-min each. Equipment was attached to a leash which was connected to a battery-powered strain gauge to measure the dog’s pulling force. All walks were video recorded for behavior analysis. Results There were statistically significant differences among the leash equipment types in pulling impulse (Newtons × seconds), (χ2(2) = 30.6, p < 0.001). Post-hoc analysis revealed significant differences in impulse between the martingale and the other equipment: harness (Z = −3.69, p < 0.001), Starmark collar (Z = −3.62, p < 0.001) and prong collar (Z = −3.92, p < 0.001). No other differences among equipment types were significant. Fifteen behaviors were examined as welfare indicators but only three: looking at the handler, lip licking, and sniffing occurred across all dogs and all walks. There was a statistically significant difference in frequency of lip licking behavior across the four types of leash-equipment (χ2(2) = 8.17, p = 0.04) and post-hoc analysis showed a difference between the martingale and the harness (Z = −2.65, p = 0.008). While our research did not provide any clear evidence of poorer welfare due to equipment type, we caution the generalizability of these findings and recommend further assessment of these items of leash-walking equipment in real-life scenarios.

IntroductionCells generate mechanical forces mainly through myosin motor activity on the actin cytoskeleton. In C. elegans, actomyosin stress fibers drive contractility of the smooth muscle-like cells of the spermatheca, a distensible, tube-shaped tissue in the hermaphrodite reproductive system and the site of oocyte fertilization. Stretching of the spermathecal cells by oocyte entry triggers activation of the small GTPase Rho. In this study, we asked how forces are distributed in vivo, and explored how spermathecal tissue responds to alterations in myosin activity.MethodsIn animals expressing GFP labeled actin or apical membrane complexes, we severed these structures using femtosecond laser ablation and quantified retractions. RNA interference was used to deplete key contractility regulators.ResultsWe show that the basal actomyosin fibers are under tension in the occupied spermatheca. Reducing actomyosin contractility by depletion of the phospholipase C-ε/PLC-1 or non-muscle myosin II/NMY-1, leads to distended spermathecae occupied by one or more embryos, but does not alter tension on the basal actomyosin fibers. However, activating myosin through depletion of the Rho GAP SPV-1 increases tension on the actomyosin fibers, consistent with earlier studies showing Rho drives spermathecal contractility. On the inner surface of the spermathecal tube, tension on the apical junctions is decreased by depletion of PLC-1 and NMY-1. Surprisingly, when basal contractility is increased through SPV-1 depletion, the tension on apical junctions also decreases, with the most significant effect on the junctions aligned in perpendicular to the axis of the spermatheca.DiscussionOur results suggest that much of the tension on the basal actin fibers in the occupied spermatheca is due to the presence of the embryo. Additionally, increased tension on the outer basal surface may compress the apical side, leading to lower tensions apically. The three dimensional shape of the spermatheca plays a role in force distribution and contractility during ovulation.

This paper explores the effect of internal technological defects on the fatigue life of carbon fiber reinforced plastic (CFRP) under simple loading waveforms. One conducted experiments on CFRP specimens with embedded artificial defects, including delamination’s (circular dry-spot) and wrinkling. Following quasi-static tests, one developed a fatigue testing program using triangular and sine waveforms. The findings indicate that these simple waveforms do not significantly affect the fatigue resistance of defect-free CFRP or CFRP with internal technological defects. The presence of the wrinkling defect significantly diminishes the fatigue resistance of CFRP. However, constructing fatigue life curves in relative terms reveals that the reduction in fatigue properties is directly related to a decrease in strength properties. In the case of delamination (dry-spot) defects, a reduction in fatigue life by approximately 2.5 times was observed across the tested range.