High Strain Levels Research Articles

Relationship between Depressive Symptoms, Caregiver Strain, and Social Support with Dementia Grief in Family Caregivers.

Background and Objectives: Dementia grief in family caregivers of people with dementia refers to grieving prior to the death of the care recipient. It is related to psychosocial risk factors that may have a negative impact on the health of these family caregivers. This study aimed to describe the relationship between depressive symptoms, caregiver strain, and social support with dementia grief in family caregivers of people with dementia. Materials and Methods: A descriptive correlational cross-sectional study was conducted. A total of 250 family caregivers of people with dementia participated. Dementia grief was the main variable, and depressive symptoms, caregiver strain, and social support were assessed. Additionally, socio-demographic data were collected. Descriptive statistics were calculated, and a bivariate correlation analysis and a multiple linear regression analysis were performed for dementia grief. Results: Higher scores for dementia grief were found in women, in family caregivers of patients at advanced stages of dementia, and in family caregivers with a low level of education. High levels of depressive symptoms and caregiver strain and low levels of social support indicated greater intensity of dementia grief. Depressive symptomatology was the variable with the greatest influence on dementia grief. Caregiver strain and social support also related to dementia grief, but to a lesser extent. Conclusions: In family caregivers, depressive symptoms, caregiver strain, and social support are related to the intensity of dementia grief, with a greater influence of depressive symptoms. Moreover, being female, having a low level of education, and caring for a care recipient at an advanced stage of dementia are factors associated with increased dementia grief. Concerning study limitations, the sample was restricted, belonging to a specific region of Spain and to a Provincial Federation of associations. It is necessary to exercise caution in generalizing results due to the sociodemographic and geographical characteristics of the sample.

Micro-mechanical investigation of maraging steel during in-situ tensile test

ABSTRACT The research aimed to examine the development of slip bands in 12Cr-9Ni maraging stainless steel through in-situ tensile testing in scanning electron microscopy (SEM) and atomic force microscopy (AFM). A comprehensive approach was employed, which included assessing strain distribution and the grain boundary character distribution (GBCD) at the intermediate plastic strain steps. During plastic deformation, dislocation pile-up leads to the formation of slip bands in the material. It was discovered that slip band formation, as well as slip line spacing, exhibit crystallographic orientation dependence. Finally, fractography was employed to unveil the likely fracture mechanism and further link it to the formation of slip bands at higher strain levels.

Antimicrobial susceptibility of bacterial clinical specimens isolated from Al-Sader Teaching Hospital in Basra-Iraq

Antibiotic resistance is a global health concern that requires multiple efforts to establish proper preventive and curative programs. This study aimed to assess the antibiotic susceptibility profiles of commonly isolated bacteria at Al-Sader Teaching Hospital, Basra-Iraq. A total of 234 clinical specimens were collected from urine, skin infections, and blood. The bacterial isolates were initially identified using standard microbiological methods, and the identification of the four most common isolates was confirmed by PCR technique using species-specific primers (malB for Escherichia coli, rpoB for Klebsiella pneumonia, OprL for Pseudomonas aeruginosa, and mecA for methicillin resistant Staphylococcus aureus). The identified bacteria were subjected to disc diffusion and VITEK2 system to test the antibiotic susceptibility. E. coli was the most prevalent in urine (51.25%), followed by S. aureus (15%), while S. aureus (31.25%) and P. aeruginosa (30.20%) were more prevalent in skin infections. S. aureus (31.57%) and E. coli (26.31%) were predominant in the blood samples. The Antibiotic susceptibility pattern of Gram-negative isolates revealed high resistance to Cefoxitin (90%), Aztreonam (87%), Ceftriaxone (87%), Piperacillin/tazobactam (85%), and Amoxicillin/clavulanic acid (85%). S. aureus showed high resistance to Cefoxitin (93%), Oxacillin (89.58), and Methicillin (91%), whereas, the highest sensitivity was recorded for Colistin (100%), Rifampin (93%), Amikacin (87%), and Meropenem (76%). A high level of multidrug-resistance strains was detected among Gram negative bacteria (76%) and S. aureus (56%). The current study provides valuable insights into the distribution of pathogenic bacteria and their antibiotic resistance patterns in different clinical samples, contributing to improved treatment strategies and infection control measures.

Biaxial Extension of Cruciform Specimens: Embedding Equilibrium Into Design and Constitutive Characterization

BackgroundMain desired features of biaxial tests are: uniformity of stresses and strains; high strain levels in gauge areas; reliable constitutive parameters identification. Despite cruciform specimen suitability to modern tensile devices, standard testing techniques are still debated because of difficulties in matching these demands.ObjectiveThis work aims at providing rational performance objectives and efficient cruciform specimens shapes in view of constitutive characterization.MethodsObjective performance is evaluated along particular lines lying on principal directions in equibiaxial tensile tests. A rich specimen profile geometry is purposely optimized via finite elements analysis by varying cost function and material compressibility. Experimental tests, monitored via digital image correlation, are carried out for validation.ResultsNew shapes are designed and tested in a biaxial tensile apparatus and show to perform better than existing ones. Elastic parameter identification is efficiently performed by only exploiting full field strain measurements along statically significant lines.ConclusionsSmall gauge areas and small fillet radii cruciform specimens approach the ideal deformation behaviour. For the constitutive parameters identification in planar tensile experiments, it suffices to monitor strains along the gauge lines.

Supporting adoptive and foster parents of adolescents through the trauma-informed e-Connect parent group: a preliminary descriptive study.

Adolescents in adoption and foster care are likely to show internalizing and externalizing problems and affective dysregulation, leading to a lower quality of parent-adolescent attachment relationships and high levels of strain for parents. This study describes the results of the first application of the trauma-informed attachment-based Connect Parent Group in an online form (e-Connect) with Italian adoptive and foster parents. In this study, we describe (1) trends in the aforementioned variables between pre- (T1) and post- (T2) intervention and (2) parents' feedback and suggestions about the intervention. Participants were 10 adoptive and 10 foster parents (53% females, Mage = 53.48; SDage = 4.93) who attended e-Connect, an attachment-focused and trauma-informed 10-session online group intervention. This intervention aims at increasing caregiver awareness of attachment and trauma concerning adolescents' problem behaviors and sensitive responsiveness, thereby leading to improvements in parent-adolescent relationship quality, decreases in adolescents' problems, and reductions in caregiver strain. One e-Connect group was offered for adoptive parents and one for foster parents. Parents completed questionnaires 1 week before (T1) and after (T2) the intervention and responded to a feedback interview following program completion. Only at the descriptive level, scores of adolescents' internalizing and externalizing problems, affective dysregulation, and caregivers' strain show decreasing trends. Parents reported high satisfaction with the program, declaring changes in parent-adolescent relationships both currently (94.7%) and anticipated in the future (100%). All parents indicated that they would recommend e-Connect to other parents. Given promising parents' feedback, the feasibility of e-Connect supporting adoptive and foster parents of adolescents can be further empirically investigated.

Tensile damage self-monitoring of carbon fiber/epoxy 3D braided composites with electrical resistance method

Electrical resistance method (ERM) has great potential in self-monitoring structural health for carbon fiber composites due to carbon fiber conductivity. Here we report the correlation between tensile damages and electrical resistance changes of 3D braided composites subjected to monotonic and cyclic tensile loading. Experimental and finite element methods were utilized to reveal the electrical resistance variation and damage evolution under monotonic tensile loading. We found that the electrical resistance changes under monotonic tensile loading could be segmented into three regions, namely, linear growth region, transition region and exponential growth region, corresponding to different damage modes. Synchronous and reversible electrical resistance changes at a low strain level (12% of fracture strain) cyclic loading proved the stability and repeatability of self-monitoring capability. While, the abrupt electrical resistance changes at a high strain level (75% of fracture strain), indicated catastrophic failure of the composites. Such kind of correspondence between tensile damages and electrical resistance change under tensile loading enables ERM to achieve the in-situ structural health monitoring of 3D braided composites without relying on external sensors.

A phenomenological constitutive model of Novel Rheo Gravity Die Cast Al-15Mg2Si-4.5Si-0.01Sr-0.015B composite

The present study discusses the high temperature deformation behaviour as well as phenomenological constitutive model development of the novel Rheo gravity die cast (RGDC) Al-15Mg2Si-4.5Si-0.01 Sr-0.015B composite. Within the scope of the study, uniaxial isothermal compression tests are performed on the RGDC Al-15Mg2Si-4.5Si-0.01 Sr-0.015B composite, covering a range of strain rates from 10−3 to 10 s−1 and deformation temperatures spanning from 250 °C to 450 °C. Analysis using X-ray Diffraction (XRD), Energy dispersive spectroscopy (EDS) and Electron Probe Micro Analyzer (EPMA) revealed the presence of distinct phases within the material, including primary Al, Mg2Si, and elemental Si. The study employed three different constitutive models i.e., the Johnson-Cook (JC), modified Johnson-Cook (mJC), and sine hyperbolic Arrhenius (shA) types, to predict the flow stress of the material as a function of strain, strain rate, and deformation temperature. The results indicated that the sine hyperbolic Arrhenius type model and the modified Johnson Cook model effectively accounted the coupling effect of strain, strain rate, and deformation temperature, which affect the flow stress. Statistical analysis, specifically Pearson coefficient correlation (R), average absolute relative error (AARE) and standard deviations, established a reasonable agreement between the predicted flow stress values and the experimental flow stress data. Furthermore, it is observed that the sine hyperbolic Arrhenius type model exhibited superior accuracy compared to the modified Johnson Cook model, particularly at higher strain levels.

Effects of semi-cyclic loading on the recovery stresses of iron-based shape-memory alloy bars

Shape-memory alloys (SMAs) have attracted considerable interest in structural engineering because of their ability to ‘memorise’ their original form when subjected to thermomechanical variations, a phenomenon termed the shape memory effect. By controlling the heating and cooling (activation) of SMAs under constrained deformation, recovery stresses can be generated, making SMAs suitable for use as prestressing reinforcement in concrete structures. However, recent studies suggest that the benefits of reinforcing with iron-based SMA (Fe-SMA) could be considerably reduced under semi-cyclic loading.This paper focuses on analysing the behaviour of 16 mm diameter Fe-SMA reinforcing bars when subjected to consecutive activations and semi-cyclic tensile tests. Activations at different temperatures (160, 200 and 250ºC) were performed, followed by semi-cyclic load tests until high strain levels were carried out. The results show a correlation between the temperature reached during the activation and the recovery stress achieved. Furthermore, the data confirms that high strain levels induced by semi-cyclic loads can lead to a complete loss of the initially generated recovery stresses. However, by re-activating the Fe-SMA samples, it is possible to restore a similar level of the initial recovery stresses. Moreover, for practical structural engineering applications in RC beams, where strain increments might be modest, only partial stress losses would be produced. These partial losses could be treated, for designing, as a prestressing loss.

Titin takes centerstage among cytoskeletal contributions to myocardial passive stiffness.

Both diastolic filling and systolic pumping of the heart are dependent on the passive stiffness characteristics of various mechanical elements of myocardium. However, the specific contribution from each element, including the extracellular matrix, actin filaments, microtubules, desmin intermediate filaments, and sarcomeric titin springs, remains challenging to assess. Recently, a mouse model allowing for precise and acute cleavage of the titin springs was used to remove one mechanical element after the other from cardiac fibers and record the effect on passive stiffness. It became clear that the stiffness contribution from each element is context-dependent and varies depending on strain level and the force component considered (elastic or viscous); elements do not act in isolation but in a tensegral relationship. Titin is a substantial contributor under all conditions and dominates the elastic forces at both low and high strains. The contribution to viscous forces is more equally shared between microtubules, titin, and actin. However, the extracellular matrix substantially contributes to both force components at higher strain levels. Desmin filaments may bear low stiffness. These insights enhance our understanding of how different filament networks contribute to passive stiffness in the heart and offer new perspectives for targeting this stiffness in heart failure treatment.

THE PROTECTIVE LIFESPAN BENEFITS OF SOCIAL SUPPORT BUFFERS CHILDHOOD ADVERSITY

Abstract Childhood adversity has negative effects across the lifespan including increased mortality risk. The support we receive from others, social support, has shown to be a protective factor against ACEs. However, little research has investigated the amplifying effects of poor social support, also known as social strain. Individuals with high levels of social strain and low levels of adversity would have the lowest mortality risk, it was hypothesized. Early life adversity was computed using 16 retrospective items assessing emotional and physical abuse, socioeconomic disadvantage, familial instability, and early-life poor health. Social support was computed using four-family, four-friend, and six-spouse items assessing reliability and emotion availability. Social strain was computed using four-family, four-friend, and six-spouse items assessing annoyance and disappointment. Cox proportional hazards models tested whether adversity, social support, and social strain were associated with the 20+year hazard of dying. Adjusting for age, gender, race, education, and marital status, higher ACEs (HR = 1.06) lower social support (HR = 1.07) and greater social strain (HR = 1.06) were all significantly associated with an increased hazard of dying (all ps < .05). A significant ACE x Social Support interaction emerged (HR = 0.95) suggesting the association between ACEs and hazard of dying was strongly positive at low levels of social support, but that the relationship was negative at high levels of support. Thus, high levels of social support buffer the negative effects ACEs have on mortality risk. This provides robust evidence that interventions increasing social support could reduce the harmful effects ACEs.

The evolution of subsurface deformation and tribological degradation of a multiphase Fe-based hardfacing induced by sliding contact

Multiphase Fe-based hardfacing alloys, for example Tristelle 5183 Fe-21%Cr-10%Ni-7.5%Nb-5%Si-2%C in wt.%, are extensively used for tribological applications, including valves, bearings and drive mechanisms, where two surfaces are unavoidably subjected to loaded sliding contact within engineering systems. In this study, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to characterise, for the first time, the tribologically affected material induced by the self-mated sliding contact of HIPed Tristelle 5183. This provided novel insight into the deformation modes which permit the accumulation of the high levels of subsurface strain required for plasticity dominated (adhesive) wear in a commercial hardfacing. In the subsurface regions furthest from the sliding contact, plastic deformation is accommodated by deformation induced martensitic transformation to ϵ-martensite and α′-martensite, twinning, the generation of planar dislocation arrangements (generated by planar slip) and the generation of dislocation tangles. Closer to the sliding contact, the subsurface becomes unstable, and nanocrystallisation driven by grain boundary mediated deformation mechanisms and crystallographic slip completely engulf the near surface microstructure. It is postulated that nanocrystalisation within the subsurface is a needed in order to accommodate the extremely high strains required in order to permit tribological degradation via plasticity dominated wear. The extrusion of metallic slivers via plastic ratcheting generates ductile shear cracks governed by plastic strain, and the failure of these slivers generates plate/flake-like wear debris.

Auxetic cementitious composites (ACCs) with excellent compressive ductility: Experiments and modeling

Auxetic cementitious composites (ACCs) with improved mechanical properties are created, by casting 3D printed polymeric auxetic reinforcement structures inside cementitious mortar. Four types of ACCs incorporating reinforcement with different auxetic mechanisms were prepared: “re-entrant” (RE), “rotating-square” (RS), “chiral” (CR) and “missing-rib” (MR). Experiments and finite element models were used to study the compressive behavior of the ACCs. The results indicate that all ACCs have high compressive ductility. Specifically, the RE shows the highest ductility, manifested by 853% and 708% higher energy absorption than the reference mortar and the auxetic structure itself, respectively. In addition, the RE and RS are found to exhibit stronger crack-arresting effect under compression. Therefore, they achieved comparable compressive strength to the reference mortar, which is considerably higher than CR and MR. Furthermore, decreasing the volumetric ratio of the auxetic structure by half, the ductility of the RS reduces by 32.2%, while decreasing the water-to-binder ratio of the cementitious matrix from 0.4 to 0.3 only increases the compressive strength by 18.5%. Moreover, the two-dimensional finite element analyses used herein show a good match with experiments but become less accurate at high strain levels, due to their inability to capture the out-of-plane failure of the ACCs.

Mechanical behaviour of ductile polymer cellular model structures manufactured by FDM

In this work, Acrylonitrile-Butadiene-Styrene model structures were manufactured by FDM, and their mechanical behaviour investigated under compression, both at small and at large strains. The structure design strategy adopted, based on the use of circular cross-section beam-like elements formed under controlled conditions, led to obtain open-cell structures (with a porosity degree of ≈ 65%) composed of unit cells with different shapes and dimensions assembled to form regularly repeating patterns. The stress-strain behaviour, from cube- and prism-shaped specimens with different sizes and loaded along different directions, was discussed in the light of the outcomes from (i) cyclic compression experiments and (ii) morphological analyses of cryogenic fracture surfaces of specimens compressed at high strain levels. The response along the 3D-stacking direction was traced back to the elastic-plastic case, with non-recoverable strain starting to accumulate between 3% and 5% strain and structure densification starting below 20%. The specimen size effects turned out to be little pronounced. Slightly higher levels of stiffness and strength were measured for the largest cube. This result was discussed on the basis of the peculiar morphology of the structure examined.

Optimization of microstructure and tensile properties for a 13Cr-1W ODS steel prepared by mechanical alloying and spark plasma sintering using pre-alloyed powder

An oxide-dispersion-strengthened (ODS) 13Cr-1W steel has been fabricated through mechanical alloying (MA) and spark plasma sintering (SPS) using pre-alloyed Fe-Cr-W-Y powder and TiO2 powder. Sufficient MA effects, indicated by homogeneous distribution of alloying elements and high level of lattice strain inside the powder, have been obtained within 20 h of high-energy ball-milling. Grain refinement of the bulk materials is successfully achieved by optimizing the sintering temperature and pressure during SPS. A fine-grained ODS steel with average grain size of 626.75 nm is prepared when sintered at 950 °C/80 MPa. Ultrafine oxide dispersoids, identified as Y2O3, Y2TiO5 and Y2Ti2O7, are observed homogeneously distributed in the steel matrix after annealing. They have a number density of 4.5 × 1022 m−3 and an average size of 11.15 nm. Tensile tests from room temperature to 700 °C are conducted to this ODS steel. It exhibits an ultimate tensile strength and a yield strength of 1559.60 MPa and 1352.82 MPa at room temperature, respectively. Due to a good combination of dislocation strengthening, grain boundary strengthening and precipitation strengthening, this alloy wins superior tensile properties over most of the commercial ODS steels and those reported in some previous studies.

Tailoring Strength and Ductility of an Fe–Mn–Al–C Low‐Density Duplex Steel by Controlling the Cooling Path after Hot Rolling

The low‐density duplex steels provide a potential for the industrial application owing to their good strength‐ductility match and reduced density. In the present work, the microstructure of an Fe–8.03Mn–6.10Al–0.4C (wt%) low‐density duplex steel was adjusted by controlling the cooling path after hot rolling, which is a conventional process during the production of steel sheets and strips. A microstructure of ferrite and austenite has been achieved by annealing the air‐cooled samples, and the microstructure of furnace‐cooled annealed samples consists of banded ferrite, austenite, and martensite. This is mainly due to the fact that the austenite is more stable by refining the grain size via embedding the needle‐like α‐ferrite. The existing of martensite and the banded microstructure in furnace‐cooled annealed samples induces the occurrence of cracks during deformation, resulting in an abrupt fracture at a relatively lower strain level. However, for air‐cooled annealed samples, a good ductility of duplex microstructure ensures that the deformation can be sustained up to a much higher strain level, and the transformation induced plasticity effect plays a positive role at the later deformation stage; this contributes to the occurrence of an extra work hardening rate recovery during deformation and thus to a good strength‐ductility match.

Оценка схемы многоканального углового прессования прутков и возможности ее применения на практике

Introduction. Deformation of low-plastic materials requires a high degree of compressive stress. This requirement is implemented, for example, in the process of equal channel angular pressing (ECAP). However, the products obtained by the ECAP method have a cross-section identical to the initial blank, which is one of the disadvantages of this method. The method of nonequal channel angular pressing (NECAP), in contrast to ECAP, makes it possible to change the shape of the initial blank towards closer to the shape of the finished product. However, the well-known NECAP device allows obtaining products only in the form of a thin strip of rectangular cross-section. Well-known devices for multichannel pressing of non-angular type also have a disadvantage — it is implemented only on horizontal type presses, where it is possible to receive long products on the workshop areas. The aim of the work is the evaluation of the bars’ multichannel angular pressing scheme, combining a change in the shape of the initial workpiece in cross-section, as well as the accumulation of a high level of strain during deformation. Research methods: finite element modeling using the DEFORM software module. Results and discussion. The paper considers the scheme of the angular pressing process with the use of a device that allows, for example, to obtain magnesium bars with a diameter of d = 4.1 mm with the number of matrix channels n = 3 from a blank of round cross-section. The container of this device in its lower part has a rectangular groove where the matrix is inserted. Modeling of the process under study using a matrix with the axes of its channels located in the plane of the orthogonal axis of the container and, in the first variant, along the axis of a rectangular groove, and in the second variant, along the radius of the container, allowed us to estimate the distribution of the average stress. It is established that the metal of the blank in both variants of the deformation process is affected by compression stresses at a high level (1,600 MPa). The assessment of the degree of deformation of the pressed bars allowed us to find out that at the initial stage of both process variants, the maximum strain degree can reach 2.6, and at the steady stage it reaches 5.0. It is established that in the case of the first variant of the matrix, the strain level along the length of the bars is lower than when using the second variant of the matrix. The difference reaches 20 %. By evaluating the distribution of the strain degree in the cross section of the pressed bars near the deformation site, it was found that in the case of the first variant of the matrix, the pressed bars of the first and third channels have an uneven dimensions, and the greater value of the strain degree is on the peripheral part of the rods from the side bordering the central bar. This difference in the strain degree reaches 20 %. When placing the second version of the matrix, this unevenness decreases to 12 %. Thus, in the case of using a matrix with the arrangement of the channel axes along the radius of the container, the strain degree is distributed more evenly compared to the strain degree when using a matrix with the arrangement of the channel axes along the axis of a rectangular groove.

Effect of meshing technique and time discretization size on thickness strain localization during hole-flanging simulation of DP980 sheet at high strain level

In the simulation of the hole-flanging process, many had reported that the effect of mesh sensitivity on strain localizations is insignificant. In this study, mesh layouts including the number of elements along the hole circumference (CD), element sizes in radial directions (R1) and the time discretization (or increment) sizes (T) are varied in the 3D FE simulation of 10-mm hole flanging process of DP980 thin sheets using a conical punch. Its effect on wall thickness distributions and forming load profiles are investigated. Also, the effect of punch surface meshing techniques i.e., analytical and discrete rigid on the distributions is investigated. The simulation results showed that the largest % wall thinning range around the expanded hole edges for punch displacement, S = 15 mm and 20 mm are 25.8–29.2% and 33.3–64.2%, respectively. The load-displacement curves during the continuous hole expansion are not linear for R1 ≥ 0.5 mm. For CD70 & R1 = 0.1 mm, the increase in T values from 0.1 s to 1.0 s has significantly increased the total simulation time by 25% due to the convergence problems. The automatic time increment mode in each step at T = 1.0 s has failed to reduce the total simulation time. The discrete rigid punch surface produces more concentrated wall thickness distributions than the analytical one, leading to higher amount of wall thinning, particularly for high S values. Since the model stiffness reduces with decreasing mesh size. It is recommended to match the simulated peak load with the experimental peak under the instability condition with a smooth hole e.g., a laser cut hole to determine the appropriate meshing method for the mesh sensitivity study. With that, the stiffness of the simulation model is calibrated with the experiment.

The Basas Spanish Squat: Superimposition of Electrical Stimulation to Optimize Patellar Tendon Strain: A Case Series.

The Basas Spanish Squat with electrical stimulation (E-stim) has shown promising results as a potential key exercise in treatment of athletes with patellar tendinopathy. Gold standard exercise therapy for tendon injuries consists of tendon loading exercises, or exercises that appropriately applies high levels of mechanical strain to the tendon. The theoretical pathway in which the Basas Spanish Squat with E-stim improves tendinopathy has been speculated to be the additional strain applied through the patellar tendon during superimposition of E-stim. This theory, however, has yet to be confirmed. The purpose of this case series was to compare patellar tendon strain, during the Basas Spanish Squat with, and without E-stim, and open kinetic chain knee extension. Four healthy participants performed the three exercises while a physical therapist collected simultaneous unilateral ultrasound images from the patellar tendon. Strain was calculated as the change in patellar tendon length during contraction divided by the resting length. Amongst all participants, patellar tendon strain was smallest during the Basas Spanish Squat without E-stim, followed by the open kinetic chain knee extension at 60% maximum voluntary isometric contraction. The Basas Spanish Squat with E-stim yielded approximately double or more strain compared to the without E-stim condition and demonstrated higher level of strain compared to open kinetic chain knee extension in all participants. The findings reflect a clear trend of increased strain through the patellar tendon when E-stim was superimposed. The results support the theory that the Basas Spanish Squat with E-stim increases patellar tendon strain and could explain the reported clinical benefits in individuals with patellar tendinopathy. 4, Case series.

Prediction of grain size and dislocation density in the cold spraying process using a dislocation-based model

The cold spray particle deposition process was simulated by modeling the high-velocity impacts of spherical particles onto a flat substrate at different velocities. In addition to simulating the single particle, this study also employed a unique simulation technique to predict the evolution of the material's microstructure under real process conditions. A dislocation-based model was implemented as a VUMAT subroutine to model the microstructure. Additionally, Python scripting was also utilized in the multi-particle impact simulation to create particles and assign velocity and interaction randomly. The relationships between stress-strain values and material microstructure are linked together. By using this model, calculations were done for the equivalent plastic strain, dislocation density, and grain size in the particle, substrate, and interface. At the interface, there were high levels of plastic strain and strain rates reaching up to, which formed a bond between the particles and the substrate. It was found that a minimum plastic strain of approximately 1 is needed to create this bond. At velocities exceeding a critical velocity, a jet was produced. The particle grain size in regions distant from the interface measured between 200 and 500 nm, which is in good agreement with the experimental results. The smallest grain size was observed at the interface, measuring 140 nm. The validation outcomes demonstrated that the suggested model effectively replicates the cold spraying process. As a result, the suggested model has the capability to predict and evaluate the changes in the material's microstructure during the cold spraying process using various factors.

Evaluation of a carepartner-integrated telehealth gait rehabilitation program for persons with stroke: study protocol for a feasibility study

BackgroundDespite family carepartners of individuals post-stroke experiencing high levels of strain and reduced quality of life, stroke rehabilitation interventions rarely address carepartner well-being or offer training to support their engagement in therapeutic activities. Our group has developed creative intervention approaches to support families during stroke recovery, thereby improving physical and psychosocial outcomes for both carepartners and stroke survivors. The purpose of this study is to test the feasibility of an adapted, home-based intervention (Carepartner Collaborative Integrative Therapy for Gait-CARE-CITE-Gait) designed to facilitate positive carepartner involvement during home-based training targeting gait and mobility.MethodsThis two-phased design will determine the feasibility of CARE-CITE-Gait, a novel intervention that leverages principles from our previous carepartner-focused upper extremity intervention. During the 4-week CARE-CITE-Gait intervention, carepartners review online video-based modules designed to illustrate strategies for an autonomy-supportive environment during functional mobility task practice, and the study team completes two 2-h home visits for dyad collaborative goal setting. In phase I, content validity, usability, and acceptability of the CARE-CITE-Gait modules will be evaluated by stroke rehabilitation content experts and carepartners. In phase II, feasibility (based on measures of recruitment, retention, intervention adherence, and safety) will be measured. Preliminary effects of the CARE-CITE-Gait will be gathered using a single-group, quasi-experimental design with repeated measures (two baseline visits 1 week apart, posttest, and 1-month follow-up) with 15 carepartner and stroke survivor dyads. Outcome data collectors will be blinded. Outcomes include psychosocial variables (family conflict surrounding stroke recovery, strain, autonomy support, and quality of life) collected from carepartners and measures of functional mobility, gait speed, stepping activity, and health-related quality of life collected from stroke survivors.DiscussionThe findings of the feasibility testing and preliminary data on the effects of CARE-CITE-Gait will provide justification and information to guide a future definitive randomized clinical trial. The knowledge gained from this study will enhance our understanding of and aid the development of rehabilitation approaches that address both carepartner and stroke survivor needs during the stroke recovery process.Trial registrationClinicalTrials.gov, NCT 05257928. Registered 25 February 2022.Trial statusThis trial was registered on ClinicalTrials.gov (NCT 05257928) on March 25, 2022. Recruitment of participants was initiated on May 18, 2022.