Decrease In Stress Research Articles

Optimisation of mechanical properties and pore structure of lightweight geopolymer concrete

Lightweight geopolymer has good physical and mechanical properties, thermal and chemical stability and low carbon dioxide emissions. The development of high-strength lightweight geopolymer concrete (LGC) for load-bearing structures can expand geopolymer applications. The use of ground granulated blast-furnace slag (GGBFS) to improve the mechanical properties and pore structure of LGC was investigated. The ultimate compressive stress of LGC containing GGBFS were analysed, as well as the variation in microscopic pore structure. Specimens of LGCs with different strengths (LC20, LC30 and LC40) were investigated. As the GGBFS content increases, the ultimate compressive stress and specific strength of LGC increases, while the strain corresponding to the peak stress decreases, indicating that the mechanical properties and deformation resistance of LGC are improved. The carbon dioxide emissions of LGC are less than those of cement-based lightweight concrete, indicating that LGC has good sustainability. Moreover, the addition of GGBFS can produce more gel and reduce the volume proportion of capillary pores and air pores, resulting in LGC densification. Recommended GGBFS contents for strength grades LC20, LC30 and LC40 are 0–12.7%, 12.7–24.6% and 24.6–30%, respectively. The LGC is lightweight and has high strength, and has potential for application in civil engineering.

Trajectories of mindfulness, flow experience, and stress during an online-based MBSR program: the moderating role of emotional exhaustion.

Despite numerous papers focusing on mindfulness at work, our knowledge about how flow experience and stress as indicators of optimal functioning and wellbeing at work evolve over time during the common mindfulness-based stress reduction (MBSR) program remains limited. Drawing from the transactional model of flow and stress, we argue that a build-up of mindfulness over the training duration not only leads to a decrease in stress but also an increase in flow experience. Thereby, we examine the moderating role of emotional exhaustion amplifying the beneficial effects of mindfulness. In a quasi-experimental study, 91 participants completed weekly questionnaires over the course of 8 weeks. Forty six participants in the experimental group took part in the MBSR program, while 45 participants were part of an inactive control group. Mindfulness and flow showed a significant linear increase over time, whereas stress exhibited a linear decrease. Those who participated in the MBSR training reported an increase in mindfulness that positively and negatively predicted the trajectories of flow and stress, respectively. Emotional exhaustion amplified the effects of the trajectory of mindfulness on the trajectories of flow and stress. These findings suggest that mindfulness can not only reduce stress but can also foster the autotelic experience of flow, especially for chronically depleted individuals. However, more research is necessary to replicate these results and address the limitations of the current study, including the quasi-experimental design, the use of self-report measures, as well as the dropout during the study period.

Utilizing combusted PET plastic waste and biogenic oils as efficient pour point depressants for crude oil

The deposition of paraffin on pipelines during crude oil transit and low-temperature restart processes poses a significant challenge for the oil industry. Addressing this issue necessitates the exploration of innovative materials and methods. Pour point depressants (PPDs) emerge as crucial processing aids to modify paraffin crystallization and enhance crude oil flow. This study focuses on the combustion of polyethylene terephthalate (PET) waste, a prevalent plastic, in two distinct oils (castor and jatropha). The resulting black waxy substances (PET/Castor and PET/Jatropha) were introduced in varying weights (1000, 2000, and 3000 ppm) to crude oil. The PET/castor oil combination demonstrated a remarkable reduction in pour point from 18 to −21 °C at 3000 ppm concentration, significantly more effective than PET/jatropha blends. Substantial decreases in viscosity (up to 75%) and shear stress (up to 72%) were also observed for both blends, most prominently at lower temperatures near the pour point. The synergistic effect of PET and oils as nucleating agents that alter crystallization patterns and restrict crystal growth contributes to this enhanced low-temperature flow. This highlights the potential of PET plastic waste as an economical, abundant, and eco-friendly additive to develop high-performance PPDs for crude oil.

Design of low‐stress ultrahigh‐gain dc–dc converter with coupled inductor

AbstractThe dc–dc converter plays a vital role in renewable energy power generation systems. To enhance the boost range and supply stable output voltage for the power grid, This paper propose an improved low‐stress ultrahigh‐gain dc–dc converter. First, a voltage multiplier cell is designed stemming from a three‐winding coupled inductor and a switched capacitor (SC), which can obtain ultrahigh voltage gain. In the improved voltage multiplier cell, the number of semiconductor devices is reduced, resulting in a decrease in capacitor voltage stress. Moreover, a passive clamp circuit uses the new SC, which can suppress oscillation peak voltage and absorb the leakage energy of the coupled winding. Furthermore, we deduce the operating mode of the proposed converter . Compared with other advanced topologies, the proposed topology outperforms boosting capacity, component stress, and efficiency. To stabilize the output voltage, the converter is closed‐loop controlled. Finally, experiments on the 180 W prototype have demonstrated the reliability and effectiveness of the proposed topology.

New Insights on Using Oral Semaglutide versus Dapagliflozin in Patients with Type 2 Diabetes and Metabolic Dysfunction-Associated Steatotic Liver Disease.

Increases in both the prevalence and severity of metabolic dysfunction-associated steatotic liver disease (MASLD) and obesity are closely related. Type 2 diabetes (T2DM) has been associated with metabolic dysfunction-associated steatohepatitis (MASH)-related cirrhosis and hepatocellular carcinoma. Semaglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist approved for the treatment of T2DM and has an important role in weight loss. Also, it may represent a new therapeutic option for the treatment of MASH in obese diabetic patients. The main outcomes were changes from baseline in liver steatosis and fibrosis at week 24. A total of one hundred eighty-seven patients with T2DM were eligible for this prospective study; ninety-five subjects were treated with oral semaglutide, and ninety-two patients were treated with dapagliflozin as an add-on to metformin. All the subjects were evaluated using Vibration Controlled Transient Elastography (VCTE) from June to December 2022. From our cohort, 54% of the patients were females, with a mean age of 59.92 ± 11.89 years and a mean body mass index (BMI) of 29.53 ± 5.33 kg/m2. Following a six-month medication period, we observed a substantial reduction in anthropometric measurements, including the BMI, waist circumference (WC), and waist-to-hip ratio (WtHr), in both groups. Regarding HbA1c, a notable decrease was observed in the semaglutide group (p < 0.001) when compared to the dapagliflozin group (p = 0.011). In addition, the liver stiffness measurement (LSM) according to VCTE improved significantly in the semaglutide group participants from 8.07 ± 2.90 kPa at baseline to 6.51 ± 3.09 kPa after medication (p < 0.001). The superior metabolic effects of semaglutide, correlated to dapagliflozin, may contribute to a more efficient decrease in hepatic stress and injury, leading to a substantial enhancement of liver function in T2DM patients. Further investigations conducted over an ideal timeframe are necessary to confirm the evidence presented in this study.

Effectiveness of Online Programmes for Family Carers of People with Intellectual Disabilities: Systematic Review of the International Evidence Base.

This systematic literature review examines the evidence base on the effectiveness of online programmes on the mental health and well-being of family carers of people with intellectual disabilities. Databases (ERIC, Medline, PsycINFO and CINAHL) were searched for intervention studies that considered online interventions for family carers of people with intellectual disabilities. Data were extracted using standardised data extraction tools. Bias was assessed using the Cochrane risk of bias tool for randomised trials (RoB 2). Screening, extraction and assessment of bias were completed independently by two members of the research team. Given the low number of included studies and different outcomes assessed within them, it was not possible to conduct a meta-analysis; therefore, data are presented narratively. Two studies met the criteria to be included in the review. Both studies utilised a feasibility randomised controlled trial methodology. One study found a significant decrease in parental stress, while the other found a significant increase in psychological well-being. Caution must be taken in drawing firm conclusions, given the small sample sizes and low retention rates in both studies. Online programmes seem to offer potential benefits to family carers of people with intellectual disabilities. However, further investigation is needed to examine these programmes, adopting a collaborative approach with family carers.

Three-dimensional characteristic and evolution of creep cavity and microcrack of HR3C austenitic heat resistant steel after long-term creep at 650 °C

Three-dimensional characteristics of creep cavities and microcracks in HR3C austenitic steel after creep at 650 °C were investigated using high resolution X-ray computed tomography (CT) and three-dimensional atomic probe (3DAP). The variation of cavity volume fraction is related to the increasing fraction of cavities undergoing growth and coalescence. Irregular lamellar or “W” shaped microcrack along the grain boundary were observed by the CT and the number large sized microcracks decreased significantly with decreasing stress levels. 3DAP results show that the concentration of P elements was high at the M23C6/γ interface at the early stage of creep. With the increase of creep time, M23C6/γ interface have been found to not only contain high concentration of P element, but also be enriched with Si. The coarsening of the carbides at the grain boundary and the enrichment of P and Si elements at the interface creates the conditions for the nucleation of creep cavities and microcracks under stress. Thus, stress has an tremendous influence on the distribution of creep cavities and the propagation path of microcracks. Additionally, with the decrease of stress, the creep damage mode changes from intergranular/transgranular mixed cracks to creep cavity.

Impaired mitochondrial quality control in fibromyalgia: Mechanisms involved in skeletal muscle alteration

Fibromyalgia (FMS) is a persistent syndrome marked by widespread musculoskeletal pain and behavioural symptoms. Given the hypothesis linking FMS aetiology to mitochondrial dysfunction and oxidative stress, we examined the biochemical correlation among these factors by studying specific proteins associated with mitochondrial homeostasis in muscle. Additionally, this study investigated the role of Boswellia serrata gum resin extract (BS), known for its various functions, including the potent induction of antioxidant enzymes, in determining protective or reparative mechanisms in the muscle cells. Sprague–Dawley rats were injected with reserpine to induce FMS.These animals exhibited moderate changes in hind limb skeletal muscles, experiencing mobility difficulties. Additionally, there were noteworthy morphological and ultrastructural alterations, along with the expression of myogenin, mitochondrial enzymes and oxidative stress markers in the gastrocnemius muscle. Interestingly, BS demonstrated a reduction in spontaneous motor activity difficulties. Moreover, BS showed a positive impact on musculoskeletal morphostructural aspects, as well as a decrease in oxidative stress and mitochondrial alterations. In particular, BS restored the mRNA expression of citrate synthase and cytochrome-c oxidase subunit II and the activity of electron transfer chain complexes. BS also influenced mitochondrial biogenesis, upregulating PGC-1α expression and the related transcription factors (Nrf1, Tfam, Nrf2, FOXO3a, SIRT3, GCLC, NQO1, SOD2 and GPx4), oxidative stress (lipid peroxidation, GSH levels and GSH-Px activity) and mitochondrial dynamics and function (Mnf2 expression and CoQ10 levels). Overall, this study underlined the key role of the mitochondrial alteration in FMS and that BS had a very high antioxidant effect in these organelles and also in the cells.

Effect of corrosion on fretting wear morphology and mechanical behaviors of wires

Corrosion and fretting wear inevitably occur in wires, which are important parts of cables. To study the wear morphology and surface mechanical behavior of wires for different fretting and corrosion times, a numerical model of fretting wear of wire with different corrosion conditions is established using MATLAB and ABAQUS software’s. Firstly, according to the surface roughness of wires under different corrosion times, the node coordinates in the numerical model are modified to simulate different rough surfaces. Secondly, the wear characteristics of wires under different fretting cycles are obtained by using a cycle jump concept and an ABAQUS user subroutine. Finally, the numerical model is validated using experimental data. The results show that when the corrosion time is 0 h, the wear area has a regular oval shape. The wear volumes of wires with corrosion times of 120 h and 480 h are the largest and the smallest, respectively. As wear volume increases, both residual surface contact pressure and stress decrease. When the corrosion time is 0 h and 120 h, the residual surface contact pressure is maximum and minimum, respectively.

Investigating Shear Stress of Ice Accumulated on Surfaces with Various Roughnesses: Effects of a Quasi-Water Layer.

The investigation of the anti-icing/deicing is essential because the icing phenomenon deteriorates the natural environment and various projects. By conducting molecular dynamics simulation, this work analyzes the effect of the quasi-water layer on the ice shear stress over smooth and rough surfaces, along with the underlying physics of the quasi-water layer. The results indicate that the thickness of the quasi-water layer monotonically increases with temperature, resulting in a monotonic decrease in the ice shear stress on the smooth surface. Due to the joint effects of the smooth surface wettability and the quasi-water layer, the ice shear stress increases and then decreases to almost a constant value when the surface changes from a hydrophobic to a hydrophilic one. For rough surfaces with stripe nanostructures, when the width of the bump for one case equals the depression for the other case, the variations of shear stress with height for these two cases are almost the same. The rough surface is effective in reducing the ice shear stress compared to the smooth surface due to the thickening of the quasi-water layer. Each molecule in the quasi-water layer and its four nearest neighboring molecules gradually form a tetrahedral ice-like structure along the direction away from the surface. The radial distribution function also shows that the quasi-water layer resembles the liquid water rather than the ice structure. These findings shed light on developing anti-icing and deicing techniques.

Calculation of Shear Stress in New-Type Composite Box Girder with Corrugated Steel Webs under Restrained Torsion

The objective of this paper is to outline a method for the systematic analysis and calculation of the constrained torsional shear stress in corrugated steel web composite box girders. Initially, leveraging Umansky’s secondary theory, the calculation formula for the constrained torsional shear stress within the composite girder is derived from the conditions of cross-sectional torque equilibrium and continuity in warping displacement. Subsequently, a torsion test is conducted using a scaled model of an actual girder. Finally, the constrained torsional shear stress of the corrugated steel web composite girder is examined based on theoretical analyses and the results of torsion testing. The influence of wing plate length and web thickness on the torsional shear stress of the composite girder is also investigated. The findings reveal a strong agreement between the experimental results obtained from model testing and the theoretical calculations. Notably, under torsional constraint, it is observed that the shear stress in the web is maximal and evenly distributed, followed by the bottom plate and then the top plate, with no discernible shear stress observed at the free end of the cantilever plate. Numerical analysis indicates that an increase in the relative width of the cantilever plate initially leads to an increase in shear stress for both the cantilever plate and roof plate, followed by a decrease until reaching a relative width value around 0.6, where the changes tend to stabilize. Moreover, an increase in web thickness results in a monotonic decrease in web shear stress. Additionally, the shear stress of the roof and bottom plate decreases initially before subsequently increasing.

Angelicin improves osteoporosis in ovariectomized rats by reducing ROS production in osteoclasts through regulation of the KAT6A/Nrf2 signalling pathway

BackgroundAngelicin, which is found in Psoralea, can help prevent osteoporosis by stopping osteoclast formation, although the precise mechanism remains unclear. MethodsWe evaluated the effect of angelicin on the oxidative stress level of osteoclasts using ovariectomized osteoporosis model rats and RAW264.7 cells. Changes in the bone mass of the femur were investigated using H&E staining and micro-CT. ROS content was investigated by DHE fluorescence labelling. Osteoclast-related genes and proteins were examined for expression using Western blotting, immunohistochemistry, tartrate-resistant acid phosphatase staining, and real-time quantitative PCR. The influence of angelicin on osteoclast development was also evaluated using the MTT assay, double luciferin assay, chromatin immunoprecipitation, immunoprecipitation and KAT6A siRNA transfection. ResultsRats treated with angelicin had considerably higher bone mineral density and fewer osteoclasts. Angelicin prevented RAW264.7 cells from differentiating into osteoclasts in vitro when stimulated by RANKL. Experiments revealed reduced ROS levels and significantly upregulated intracellular KAT6A, HO-1, and Nrf2 following angelicin treatment. The expression of genes unique to osteoclasts, such as MMP9 and NFATc1, was also downregulated. Finally, KAT6A siRNA transfection increased intracellular ROS levels while decreasing KAT6A, Nrf2, and HO-1 protein expression in osteoclasts. However, in the absence of KAT6A siRNA transfection, angelicin greatly counteracted this effect in osteoclasts. ConclusionsAngelicin increased the expression of KAT6A. This enhanced KAT6A expression helps to activate the Nrf2/HO-1 antioxidant stress system and decrease ROS levels in osteoclasts, thus inhibiting oxidative stress levels and osteoclast formation.

Rough bed hydrodynamics under wave-current interactional flow field: double averaging approach

ABSTRACT The effect of surface wave on the double-averaged (DA) current-only flow properties is examined over two different types of rough beds comprising hemispherical elements with regular and staggered arrangements. For each case, the relative roughness spacing of p/r = 4 is maintained, where p = pitch distance and r = hemisphere height. The changes in turbulence characteristics against the water depth are analysed for superimposed surface waves propagating along the current with 1 and 2 Hz frequencies. The effect of regular and staggered roughness arrangements on different turbulence characteristics is explored. Results demonstrate that the DA stream-wise velocity decreases and increases at the outer region and within the roughness region, respectively, due to wave propagation. Owing to the surface wave, the DA intensity and form-induced intensity increase above the roughness layer and decrease within the bottom boundary layer. The values of form-induced intensities are smaller (greater) than the DA turbulence intensities at each considered flow depth within the roughness (outer) layer. For the entire flow depth, the values of DA Reynolds stress decrease due to wave interactions along a steady current. Again, the turbulence is observed to be close to isotropic for the current-only flow at the outer zone, while the flow transits to an anisotropic state with wave imposition on current. Further, the computed values of the turbulence indicator and dispersion functions are used for the identification of the level of turbulence and dispersion at each flow depth for the locations upstream and downstream of a hemisphere in the hemispherical bed.

Finite element analysis of mechanical stress in a cementless tapered-wedge short stem in the varus position

BackgroundIn recent years, the use of tapered-wedge short stems has increased due to their ability to preserve bones and tendons. Surgical techniques occasionally result in a varus position of the stem, which is particularly pronounced in short stems. Although the varus position is not clinically problematic, there are reports of an increased incidence of stress shielding and cortical hypertrophy. Thus, we evaluated and examined the acceptable range of varus angles using finite element analysis.MethodsPatients diagnosed with osteoarthritis of the hip joint who had undergone arthroplasty were selected and classified into three types [champagne-flute (type A), intermediate (type B), and stovepipe (type C)]. Finite element analysis was performed using Mechanical Finder. The model was created using a Taperloc microplasty stem with the varus angle increased by 1° from 0° to 5° from the bone axis and classified into seven zones based on Gruen’s zone classification under loading conditions in a one-leg standing position. The volume of interest was set, the mean equivalent stress for each zone was calculated.ResultsA significant decrease in stress was observed in zone 2, and increased stress was observed in zones 3 and 4, suggesting the emergence of a distal periosteal reaction, similar to the results of previous studies. In zone 2, there was a significant decrease in stress in all groups at a varus angle ≥ 3°. In zone 3, stress increased from ≥ 3° in type B and ≥ 4° in type C. In zone 4, there was a significant increase in stress at varus angles of ≥ 2° in types A and B and at ≥ 3° in type C.ConclusionIn zone 2, the varus angle at which stress shielding above Engh classification grade 3 may appear is expected to be ≥ 3°. Distal cortical hypertrophy may appear in zones 3 and 4; the narrower the medullary cavity shape, the smaller the allowable angle of internal recession, and the wider the medullary cavity shape, the wider the allowable range. Long-term follow-up is required in patients with varus angles > 3°.

Affirmative Mindfulness, Acceptance, and Compassion-Based Group Intervention for Sexual Minorities (Free2Be): A Non-Randomized Mixed-Method Study for Feasibility with Exploratory Analysis of Effectiveness

ObjectivesDespite sexual minority (SM), i.e. individuals who identify as lesbian women, gay men, bisexual, or pansexual, individuals presenting worse mental health outcomes when compared to heterosexual individuals, they face more difficulties in accessing affirmative and quality health services. This study is a mixed-method non-randomized single-arm trial targeting SM individuals assessing the feasibility and exploratory findings from an affirmative mindfulness, acceptance, and compassion-based group intervention (Free2Be).MethodEighteen participants who self-identified as SM, with a mean age of 30.80 years old, underwent a face-to-face group intervention with 13 weekly sessions (Free2Be). Feasibility was assessed in three domains (acceptability, practicality, and preliminary effectiveness) with self-report questionnaires and hetero-report interviews, during and after the intervention, and using a mixed-methods approach. Using a pre–post and participant-by-participant design, changes were assessed in self-reported internalized stigma, psychopathology indicators, and mindfulness, acceptance, and compassion processes.ResultsThe Free2Be was acceptable and feasible in all three domains. Participants who completed the intervention (≥ 80% of attendance) revealed significant or reliable decreases in stress and social anxiety symptoms, self-criticism, and fear of compassion for the self.ConclusionsThe study provides evidence of the feasibility of the intervention. This affirmative mindfulness, acceptance, and compassion-based group intervention seems to be feasible and acceptable for SM individuals. These promising findings warrant further investigation within a pilot study.

Effectiveness of meditation on wellness management among corporate employees in India: An interventional study.

Urban corporate sector relies heavily on workplace well-being, with meditation being a potent stress reduction method that significantly enhances the quality of life (QoL) and wellness. The study aims to assess the effectiveness of meditation on wellness management among corporate employees in India. The quasi-experimental controlled study design was employed from May to June 2021, which assessed stress, QoL, and wellness indices (satisfaction with life, well-being) with meditation practice as the intervention. The online questionnaire incorporates questions from the Depression, Anxiety, Stress Scale, World Health Organization (WHO) QoL Scale, Five-item Satisfaction with Life scaleand WHO-5 Well-being Index. A nonrandom sampling technique selected 146 and 74 subjects in the intervention and control groups, respectively, among the employees of Star health- and allied insurance company. The data was analyzed using SPSS V27 (©IBM SPSS Statistics). The Wilcoxon signed rank test for the dependent groups, and Mann-Whitney U test for the independent groups (between subjects) was performed. Among a total of 220 subjects who enrolled in the recruitment survey, 146 subjects underwent the intervention thus providing a response rate of 66.4%. For the intervention group, the difference (within group) in mean scores between baseline and endline assessment shows a reduction in stress (0.02) and significant improvement in QoL (0.21) and wellness indices (satisfaction with life: 0.21, well-being: 0.24). The difference (betweenthe experimental and control groups) in mean endline scores shows a decrease in stress (0.07), an increase in wellness indices (satisfaction with life: 0.12, well-being: 0.23), and a significant change in the QoL(0.17). Meditation intervention in corporate wellness programs enhances the QoL, wellness, and stress management, establishing the effectiveness of health profile-raising ingenuities at the workplace.

Mental Health, Spirituality, and Self-Compassion Among K–12 Music Teachers During the COVID-19 Pandemic

Abstract We examined the influence of gender, age, and death of loved ones due to COVID-19, race/ethnicity, mode of instruction (hybrid, in-person, etc.), general religiosity, dispositional spirituality, and self-compassion among kindergarten through 12th-grade (K–12) music educators (N = 637) in order to assess how these factors impacted their mental health approximately 1 year after the onset of the COVID-19 pandemic. Our findings indicate a weak to moderate influence on mental health attributable to religiosity and spirituality, with feelings of connection to a higher power predicting better mental health while feelings of connection to other human beings and nature predicting the opposite. Additionally, there was a strong and statistically significant relationship between self-compassion and positive mental health, accounting for between a .87 to 1.09 decrease in stress, depression, and anxiety among participants based on one-unit increases in self-compassion. We discuss implications for music education research as well as preservice and in-service professional development based on these findings.

Increasing Exploitation Durability of Two-Layer Cast Mill Rolls and Assessment of the Applicability of the XGBoost Machine Learning Method to Manage Their Quality.

The increase in exploitation durability of two-layer cast rolls with the working layer made of high chromium cast iron allows one to significantly improve the quality of rolled metal as well as to increase the economic efficiency of the manufacturing process. However, it is severely hindered due to the massiveness of castings, the impossibility of both evaluating mechanical properties along the depth of the working layer, and providing the structural uniformity of the working surface and the decrease in stresses. In our research, aiming to enhance the exploitation durability of sheet rolls, it is recommended to achieve structural uniformity by CuMg alloying, which increases the concentration of copper up to 2.78 wt.% in certain zones and, owing to the accelerated austenite decomposition at a high temperature during the cool-down of the castings, led to the reduction in excessive strength and the level of heat stresses in the castings. We propose the regimes of cyclic heat treatments which, due to the decomposition of retained austenite and the fragmentation of structure, control the level of hardness to reduce and uniformize the level of stresses along the length of a barrel. A further improvement in the predictions of exploitation durability using XGboost method, which was performed based on the chemical composition of the working layer of high-chromium cast iron and heat treatment parameters, requires taking into account the factors characterizing exploitation conditions of specific rolling mills and the transformations of structural-phase state of the surface obtained by a non-destructive control method. As the controlled parameter, the hardness measured on the roll's surface is recommended, while the gradient change in mechanical properties along the working layer depth can be feasibly analyzed by a magnetic method of coercive force measuring.

Barefoot walking improves cognitive ability in adolescents.

Walking can have a positive impact on cognitive function in adolescents. This study aimed to compare the effects of walking with sneakers and barefoot on cognitive ability in adolescents. Fifty-nine adolescent male students were included in the study and assigned to the control (n = 20), sneaker (n = 19), and barefoot (n = 20) groups. The barefoot and sneakers group performed a 40-min walking exercise four times a week for 12 weeks during the morning physical activity time, while the control group performed self-study. Electroencephalogram (EEG) and brain activity variables were measured before and after the exercise program. The results showed that after 12 weeks, the barefoot group had a significant decrease in Gamma and H-beta waves and a significant increase in sensorimotor rhythm (SMR) and Alpha waves. Conversely, the control group showed a significant decrease in SMR waves and increase in Theta waves. The sneaker group showed a significant decrease in SMR waves alone. In an eyes-open resting state, the barefoot group showed a significant increase in H-beta, M-beta, SMR, and Alpha waves. The barefoot group also had a significant increase in cognitive speed and concentration and a significant decrease in brain stress. Taken together, barefoot walking can effectively enhance cognitive ability in adolescents, as demonstrated by the significant variation in EEG activity. This research highlights the potential benefits of barefoot walking as a simple and effective form of exercise for enhancing cognitive function in adolescents.

Influence of friction and back stresses evolution on cyclic softening of laser powder bed fusion Ti-6Al-4V ELI alloy

Laser Powder Bed Fusion (LPBF) of Ti-6Al-4V ELI enables the fabrication of complex and individualized load-bearing patient-specific implants (PSI). These PSI are subjected to cyclic loading, which necessitates their fatigue performance evaluation. In this work, the fatigue properties of LPBF Ti-6Al-4V ELI in heat-treated conditions were characterized by studying the low cycle fatigue (LCF) behavior and underlying deformation mechanism. The fully reversed strain-controlled fatigue tests were performed at various strain amplitudes at room temperature. The ratio of fatigue life of conventional wrought alloy and LPBF Ti-6Al-4V ELI at the lowest (0.8 %) and the highest (1.8 %) strain amplitudes were found to be approximately 2.7 and 4.5, respectively. Further, the softening response during fatigue loading was correlated to the variation in the back and friction stresses. The TEM observations revealed that the dislocation pileup along α/β interfaces caused an increase in dislocation density, which drives the increase in back stress. However, the ease of slip transmission at high strain amplitude (1.8 %) reduced the heterogeneity between α and β phases, causing a decrease in the back stress. The TEM observations further suggested that the dislocation annihilation and subsequent rise in dislocation-free zones in α-phase reduced the friction stress at all strain amplitudes, which resulted in cyclic softening of LPBF Ti-6Al-4V ELI.