Decrease In Stress Research Articles

The Impact of a Non-Uniform and Transient Magnetic Field on Natural Convective Jeffrey Fluid Flowing over a Heated Porous Plate: A Comparitive Study

Examining the effects of varying transient magnetic fields and their orientations on boundary layers aids in understanding the flow in complex surface geometries, turbulence control, drag reduction, aircraft and ship design, groundwater management, and the study of construction and coastal engineering. The study introduces a novel dynamics of the boundary layer of a natural convective Jeffrey fluid flowing over an erect porous moving plate under the influence a non-uniform and transient magnetic field M ˜ that grows exponentially over time with α as an accelerating parameter. The governing partial differential equations (PDEs) were non-dimensionalized using similarity variables and then solved analytically using the perturbation technique. The impact of various thermosphysical properties including chemical reactions, thermal source, Jeffrey fluid parameter and plate permeability on the fluid flow were presented graphically utilizing finite difference approximation(FDA) technique in MATLAB ODE15s solver. The study highlighted a notable decrease in shear stress (skin friction) by introducing M ˜ to the vertical plate results in the reduction of momentum boundary layer, accompanied by an increment in thermal boundary layer. Also, the results shows that increasing the magnitude of α leads to decrease the velocity and increase the temperature distribution curve. Additionally, the concentration profile was also found to decrease with stronger chemical reactions. Furthermore, key parameters like heat and mass flux were estimated and discussed through comparison tables. Understanding the effects of unsteady and externally applied increasing magnetic field M ˜ on viscous fluid flow have potential applications in biomedical engineering, such as the design of magnetic drug delivery systems and the analysis of blood flow in human body.

Effects of glucagon-like peptide-1 receptor agonists, sodium-glucose cotransporter-2 inhibitors and their combination on mitochondrial-derived peptide-c and on markers of neurohumoral activation

Abstract Background/Introduction Type-2 diabetes mellitus (T2DM) is associated with increased prevalence of cardiovascular disease. Purpose We investigated the effects of insulin, glucagon like peptide-1 receptor agonists (GLP-1RA), sodium-glucose cotransporter-2 inhibitors (SGLT-2i) and their combination on mitochondrial-derived peptide-c (MOTS-c), N-terminal pro B-type natriuretic peptide (NT-proBNP), growth differentiation factor (GDF)-15, oxidant and antioxidant biomarkers and cardiovascular function of T2DM patients. Methods A total of 160 T2DM patients were randomized to insulin (n = 40), liraglutide (n = 40), empagliflozin (n = 40) or their combination (GLP-1RA+SGLT-2i) (n = 40) as add-on to metformin. We measured at baseline, at 4 and at 12 months of treatment: a) plasma levels of MOTS-c, NT-proBNP and GDF-15, b) thiobarbituric acid reactive substances (TBARS), as an oxidant biomarkers, and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), as an antioxidant biomarker, and c) global left ventricular longitudinal strain (GLS) and global work index (GWI) using speckle-tracking imaging. Results Twelve months after treatment, treatment with SGLT-2i and GLP-1RA+SGLT-2i improved MOTS-c (14.89 ± 11.27 vs. 7.26 ± 4.21 ng/mL, p=0.009, 6.49 ± 3.91 vs. 5.6 ± 3.38 ng/mL, p=0.029, respectively), while treatment with insulin and GLP-1RA had a neutral effect on this biomarker (p > 0.05; Table). GLP-1RA, SGLT-2i and their combination showed a greater reduction of NT-proBNP (-43.1% vs. -54.2% vs. -56.9% vs. -14.7%; Figure) and GDF-15 (-14.8% vs. -15.2% vs. -16.1% vs. -0.9%) than insulin (p < 0.05 for all comparisons), despite the fact that all patient achieved adequate glycemic control. GLP-1RA or GLP-1RA+SGLT-2i provided a remarkable reduction of TBARS and increase of GLS and GWI compared to insulin or SGLT-2i (p < 0.05). In all patients, at 4 and at 12 months, the percentage reduction of NT-proBNP was associated with the improvement of TBARS, GLS and GWI (p < 0.05). The percentage reduction of GDF-15 was correlated with the increase of ABTS and with the improvement of GLS at 4 and 12 months (p < 0.05). In SGLT-2i group, the percentage increase of MOTS-c was related with the percentage reduction of GDF-15 (r = 0.81, p = 0.005) at 12 months. Conclusions Twelve-month treatment with GLP-1RA, SGLT-2i and their combination resulted in reduction of cardiac biomarkers in parallel with a greater decrease of oxidative stress than insulin in T2DM. SGLT-2i appears more effective in the improvement of MOTS-c and markers of neurohumoral activation.TableFigure

Does mindfulness program reduce stress and enhance self-kindness in schools? Healthy Learning Mind

Abstract Introduction There is a scarcity of research with high quality methods on the effectiveness of mindfulness-based interventions (MBIs) on adolescents’ mental well-being. This study investigates the MBI effects on adolescents’ stress and self-kindness with an extensive cluster RCT design, and a role of self-kindness as a mediator for the association between the MBI and stress. Additionally, the study explores how age, gender, and an independent mindfulness practice moderate the effects on the outcomes. Methods Participants (Finnish students, aged 12-15 years) were randomized to a MBI group (N = 1646), an active relaxation control group (N = 1488), and an inactive control group (N = 385). The outcomes were measured at the baseline (T0), at 9-week post-intervention (T9), and at 26-weeks follow-up (T26). Results Overall, the MBI was more effective in stress reduction when compared to the active control at T9 (β = -0.04, p < 0.01, d = -0.11) and T26 (β = -0.04, p = 0.02, d = -0.11). Furthermore, students in the MBI group who carried out their regular mindfulness home practice showed greater decrease of stress. There were no MBI effects on self-kindness, nor did a change of self-kindness mediate the effects of MBI on stress. Discussion These findings demonstrate that the 9-week MBI is slightly more effective to reduce stress relative to relaxation training. Key messages • The result highlight the potential of MBI in increasing the stress management among students in school context. • To ensure the effectiveness of MBIs in school context we need to teach these skills to teacher students already during their basic education in educational institutions and universities.

Mindfulness Exercises Reduce Acute Physiologic Stress Among Female Clinicians.

Approximately 50% of clinicians experience excessive emotional, physical, and mental stress, with repercussions across the entire medical system. Mindfulness exercises may mitigate this excessive stress. Heart rate variability (HRV) is an objective stress measure that can quantify which mindfulness exercises provide the greatest stress reduction. To define the impact of specific mindfulness exercises on HRV, a surrogate for physiologic stress, and the relationship between physiologic (HRV) and subjective stress measured by the State-Trait Anxiety Inventory during a one-day mindfulness workshop. This was a prospective observational pilot study performed at a quaternary children's hospital with diverse subspecialists of pediatric nurses, nurse practitioners, and physicians. Our primary outcome measure was change in HRV from baseline during three mindfulness exercises. The grounding, deep breathing, and body scan exercises all produced statistically significant changes in HRV among our 13 female participants. The body scan exercise produced statistically significant changes in all studied HRV parameters compared with baseline. We observed significant increases in Root Mean Square of Successive Differences between normal heartbeats (p = 0.026), high frequency (p ≤ 0.001), and the parasympathetic nervous system index (p ≤ 0.001) reflecting increased parasympathetic tone (e.g., relaxation), whereas sd 2/sd 1 ratio (p ≤ 0.001) and the stress index (p = 0.004) were decreased reflecting sympathetic withdrawal (e.g., decreased stress). Subjective stress decreased after 1-day mindfulness training (44.6 to 27.2) (p < 0.001). Individuals with the largest decrease in subjective stress also had the most improvement in HRV during the body scan exercise. Clinician stress levels (HRV) improved after participating in grounding, deep breathing, and body scan meditations, which may highlight their importance as stress reduction tools for clinicians. Monitoring of HRV during mindfulness exercises may provide deeper understanding of which specific exercises produce the greatest physiologic stress reduction for individual participants and the trend of these changes over time.

IER3IP1 mutations cause neonatal diabetes due to impaired proinsulin trafficking.

Immediate early response 3 interacting-protein 1 (IER3IP1) is an endoplasmic reticulum resident protein, highly expressed in pancreatic cells and the developing brain cortex. Homozygous mutations in IER3IP1 have been found in individuals with microcephaly and neonatal diabetes, yet the underlying mechanism causing beta cell failure remains unclear. Here, we utilized differentiation of genome edited-stem cells into pancreatic islet cells to elucidate the molecular basis of IER3IP1 neonatal diabetes. Using CRISPR-Cas9, we generated two distinct IER3IP1-mutant human embryonic stem cell lines: a homozygous knock-in model of a patient mutation (IER3IP1V21G), and a knockout model (IER3IP1-/-). While these mutant stem cell lines differentiated normally into definitive endoderm and pancreatic progenitors, we observed that IER3IP1-KO stem cell derived-islets (SC-islets) presented a significant decrease in beta cell numbers and elevated ER stress. Retention Using Selective Hooks (RUSH) assay revealed three-fold reduction in ER-to-Golgi trafficking of proinsulin in IER3IP1 mutant beta cells. Additionally, IER3IP1 mutant SC-islets implanted into immunocompromised mice displayed defective human insulin secretion, indicating the deleterious impact of IER3IP1 mutations on beta cell function. Our study provides valuable insights into the role of IER3IP1 in human beta cell biology and establishes a useful model to investigate ER-to-Golgi trafficking defects within beta cells.

The Impact of COVID-19 Vaccination on Oxidative Stress and Cardiac Fibrosis Biomarkers in Patients with Acute Myocardial Infarction (STEMI), a Single-Center Experience Analysis

The relationship between the classical cardiac biomarker and acute myocardial infarction (STEMI) in patients with COVID-19 is far from being elucidated. Furthermore, superoxide dismutase (SOD), a marker for oxidative stress, was associated with cardiac ischemia. Also, Galectin-3 is significant for defining the relationship between cardiac fibrosis and COVID-19. There are no studies on the effect of SARS-CoV-2 virus infection and vaccination on patients with STEMI and biomarkers above-mentioned. Aim: our single-center prospective study assesses the relationship between COVID-19 infection with/without vaccination and the value of SOD and Galectin-3 in STEMI patients. Material and methods: In total, 93 patients with STEMI and SARS-CoV-2 virus infection were included in the analysis, patients were divided in two groups based on COVID-19 vaccination status. Echocardiographic and laboratory investigations for cardiac ischemia, oxidative stress, and cardiac fibrosis biomarkers were investigated. Results: In total, 93 patients were included, the majority of which were male (72.0%), 45.2% (n = 42) were vaccinated against SARS-CoV-2; the mean age of vaccinated patients is 62 years, and 57% (n = 53) are smokers; blood pressure is found with a higher frequency in unvaccinated people (62.7%) compared to 28.6% in vaccinated people (p = 0.015), and 90.5% of the vaccinated people presented STEMI, compared with 96.1% of the unvaccinated ones. Revascularization with one stent was achieved in 47.6% of the vaccinated people and 72.5% for the unvaccinated people (p = 0.015). Galectin-3 was slightly more reduced in the vaccinated patients compared to the unvaccinated patients (0.73 vs. 0.99; p = 0.202), and the average level of Cu/ZnSOD was slightly more reduced in vaccinated patients compared to the unvaccinated patients (0.84 vs. 0.91; p = 0.740). Conclusions: Regarding patient’s SARS-CoV-2 infection functional status, the results from our single-center analysis did not find a statistically significant decrease in oxidative stress and cardiac fibrosis biomarkers along with cardiovascular complication following STEMI treated with percutaneous coronary angioplasty (PCI) in the case of patients with COVID-19 vaccination compared with patients who did not receive COVID-19 vaccine. Anyway, our data suggest that contemporary PCI techniques may offer an alternative revascularization strategy that enables complex CAD COVID-19 patients to be safely discharged from hospital.

Parameter optimization design of the helmet liner structure for mitigating traumatic brain injury under impact loading

Abstract Helmets play a crucial role in protecting motorcycle riders during two-wheeler accidents by reducing the risk of head injuries. This study investigated the complex interplay between the density, Poisson’s ratio, and Young’s modulus of a helmet liner and their impact on biomechanical factors contributing to traumatic brain injury during collisions. A validated finite element model of a 50th percentile detailed human head was initially used, followed by the development of a coupled helmet head model for collision simulations. The accuracy of the model was assessed by comparing the center-of-mass acceleration data of the head with the experimental results. This study analyzed the von Mises stress, skull stress, and intracranial pressure, and the results revealed patterns in stress distribution and the potential for cranial and brain injuries. Stress concentrations were observed in the cervical region before the impact, characterized by compressive stress on the impacted side and tensile stress on the opposite side, with peak stress levels found in the temporal bone base and frontal bone. After the impact, brain inertia–driven movements can further increase the risk of traumatic brain injury. The study found a positive correlation between liner density and center-of-mass acceleration of the head in the absence of bottoming out of the liner. By optimizing the liner properties, the study achieved a 4.5% reduction in head acceleration, a 10.1% decrease in skull stress, and a 19.8% reduction in intracranial pressure. These findings offer valuable insights for biomechanical research on head injuries caused by traffic accidents and for improving helmet designs to enhance protective measures.

Characterize the influences of hydraulic fracturing on preventing rock burst from the stress and vibration fields

The thick and hard roof (THR) is a significant factor that induces rock burst incidents. Traditional deep-hole blasting methods struggle to effectively relieve pressure for the high-level THR on a large scale. Although the horizontal staged hydraulic fracturing technology can crack high-level rock stratas, its impact on roof fracture still needs to be clarified, and there need to be more effective methods to evaluate its pressure relief effect. This paper conducted a comparative engineering test of local hydraulic fracturing pressure relief and load reduction on the working face to address this gap. The key layer theory and mine earthquake distribution were used to identify potential hazards of rock strata and the fracturing strata. Revealed the spatial and temporal evolution rules of microseisms induced by mining work, the failure mechanism of high-energy mine earthquakes, the evolution characteristics of source mechanical parameters, and the evolution characteristics of the stope stress field. The results indicate that after fracturing microseisms during mining presented exhibit a uniform distribution of high frequency and low energy. The fracture fragmentation of the roof rock was reduced, and the range of mining disturbance was minimized. High-energy mine earthquakes induced by mining are transferred to the goaf. Simultaneously, the corner frequency and stress decrease while the rupture radius and the shear component of the failure mechanism increase. The integrity of the THR is compromised, and fracture propagates and slips along the pre-crack. The roof of the working face experiences localized pressure, with decreased periodicity and intensity, reducing the overall static load level of the coal seam under the fracturing area. The research findings serve as a valuable reference for further investigations into the mechanism and risk assessment of hydraulic fracturing in preventing and controlling rock burst.

Probiotics modulation of the endotoxemic effect on the gut and liver of the lipopolysaccharide challenged mice

The multistrain probiotics’ efficacy in ameliorating the endotoxemic effect in Lipopolysaccharide (LPS) challenged mice was evaluated with the agonist of anti-inflammatory peptide, neurotensin (NTS), especially targeting the inflammation of the gut and liver. Swiss Albino Mice (Female, 8 weeks old) were maintained in eight groups: Group I as Control, Group II-Group V were exposed to intraperitoneal (i.p.) LPS (1 mg/kg bw) for 5 days. After that, Group III and Group VI were administered probiotics orally (0.6 gm/kg bw/day), Group IV and Group VII with NTS receptor 1 (NTSR1) agonist PD149163 (50 µg/kg bw/day i.p.), and Group V and Group VIII co-administered with probiotics and PD149163 for 28 days. Group II (LPS-exposed) was maintained without any further treatment; mice of all the groups were sacrificed at day 34. In the LPS-exposed mice, endotoxemia was distinct from a significant (P < 0.001) increase of plasma pro-inflammatory cytokines (TNF-α; IL-6), a decrease of anti-inflammatory cytokine (IL-10), oxidative stress, and inflammation of the gut and liver. Increased serum transaminases indicated hepatic inflammation. A decreased population of the bifidobacteria and increased clostridia indicated microbiota dysbiosis. Probiotics when used as an adjunct along with PD149163 have shown better efficacy in inflammation modulation as reflected in the significantly decreased (P < 0.001) inflammatory mediators, oxidative stress, restoration of the beneficial bacterial population, along with a significant reduction in histopathological scores of the gut and the liver than when used alone. This study suggests probiotics could be used as an adjunct in clinical practice along with anti-inflammatory drugs for better therapeutic efficacy.

Analysis of the tooth-root stress of external spur gears with high effective contact ratio

For spur gears with contact ratio close to 2, the extension of the contact interval resulting from loaded tooth deflections and local contact deformations may result in an effective contact ratio above 2. In these cases, the load is transmitted by at least two tooth-pairs, the maximum load and tooth-root stress decrease, and therefore the calculation methods of the gear rating Standards ISO and AGMA provide very conservative results. In this work, two models are applied to the calculation of the tooth-root stress of load-induced high contact ratio external gears: (i) an analytic model of load sharing, based on the minimum energy method, and (ii) a finite element model, which validates the results obtained from the previous model. Obtained values of the stress are compared with those provided by ISO and AGMA rating methods, which do not account for the stress reduction due to the higher contact ratio. A new modification coefficient is proposed to correct these conservative values, which allows the AGMA and ISO geometry factors to remain as no load-dependent factors and keep their actual calculation methods and significance.

Effect of cryogenic treatment time on mechanical properties of Sm2Co17 permanent magnets

Sm2Co17 permanent magnets are widely used in aerospace, radar communication, rail transit, and various other fields. However, their brittleness restricts their application. Improving their mechanical properties is of practical interest. Cryogenic treatment can be used as a means to enhance the mechanical properties of Sm2Co17 permanent magnets. However, the specific relationship between cryogenic treatment time and the properties of samarium-cobalt magnets has not yet been fully understood. In light of this, this paper focuses on exploring the influence of cryogenic treatment time on the mechanical properties of Sm2Co17 permanent magnets, aiming to provide a foundation for further elucidating this relationship. The results show that the mechanical properties can be significantly affected by cryogenic treatment time, with the flexural strength and elastic modulus increasing by 27.6 % and 9.6 % respectively when 3 h of treatment. However, the effect of further extending the treatment time to 6 h is not significant. In addition, the cryogenic treatment time has no adverse effect on magnetic properties. Additional analysis reveals that the enhancement in mechanical properties is primarily attributed to the decrease in residual stress and lattice constants. This study provides valuable insights into optimizing cryogenic treatment parameters to enhance the mechanical performance of Sm2Co17 permanent magnets while preserving their magnetic properties.

Generalisation of the yield stress measurement in three point bending collapse tests: application to 3D printed flax fibre reinforced hydrogels

This paper describes the extrusion pressure's effect on composite hydrogel inks' filaments subjected to three point bending collapse tests. The composite considered in this work consists of an alginate-poloxamer hydrogel reinforced with flax fibres. Increased extrusion pressure resulted in more asymmetrical filaments between the support pillars. Furthermore, the material and printing conditions used in the present study led to the production of curved specimens. These two characteristics implicitly limit the validity of the yield stress equations commonly used in open literature. Therefore, a new system of equations was derived for the case of asymmetrical and curved filaments. A post-processing method was also created to obtain the properties required to evaluate this yield stress. This new equation was then implemented to identify the strength of failed hydrogels without flax fibre reinforcement. A statistical analysis showed this new equation's significance, which yielded statistically higher (i.e. 1.15 times larger) strength values compared to the numbers obtained with the open literature equations. At larger extrusion pressures, longer periods were needed for the material to converge towards its final shape. Larger extrusion pressure values led to lower yield stresses within the composite hydrogel filament: a 5 kPa increase in extrusion pressure lowered the yield stress by 19%. In comparison, a 15 kPa increase led to a 29% decrease in the yield stress. Overall this study provides guidelines to standardize three point bending collapse tests and analysis comparison between different materials.

Coulomb Stress Change of Active Fault in South Sumatra Region Revealed from Kerinci Earthquake October 06, 1995 Mw 6.7 and Sungai Penuh Earthquake October 01, 2009 Mw 6.6

We successfully highlight the correlation of Static Stress Change (ΔCFF) in the Kerimci earthquake October 06, 1995 Mw 6.7 and Sungai Penuh earthquake October 01, 2009 Mw 6.6 earthquakes to the seismicity conditions. The data used in this study are focal mechanism obtained from Global Centroid Moment Tensor (GCMT) and seismicity obtained from USGS with M ≥ 4 after the main earthquake with a time span of 11 years. ΔCFF obtained in the Mentawai Fault System area has increased coulomb stress. ΔCFF obtained in the Suliti Segment, Ketaun Segment, and Back arc Basin of Jambi experienced an increase in stress, which can indicate the potential for future earthquakes, but there was no increase in seismicity. Besides that, ΔCFF in areas that experienced a decrease in stress, experienced an increase in seismicity. This is caused by background seismicity in the area and several factors influence the results of the calculation of ΔCFF against seismicity. Simplicity in calculation causes difficulty in explaining seismicity, especially in the blue lobe. Moreover, the use of receiver fault mechanism produces a very large error in the complex regional stress field. The use of a constant friction coefficient also produces a very large error in the calculation.

Simulation study of turning-ultrasonic rolling compound processing for 42CrMo steel

The ultrasonic rolling processing technology has been shown to significantly reduce surface roughness and enhance the residual stress of parts, thereby improving their surface properties and extending their service life. This technology is particularly effective for the precision machining and surface strengthening of ultra-high-strength steel 42CrMo. This study aims to investigate the impact of turning pre-processing on the distribution of residual stress during ultrasonic rolling, a simulation model incorporating turning pre-processing was developed and used to conduct ultrasonic rolling simulation experiments, enabling the analysis of residual stress distribution patterns. Concurrently, ultrasonic rolling strengthening experiments were performed to validate the accuracy of the simulation model. The results confirm that with increasing rotational speed and feed rate, residual stress decreases, whereas with increasing static pressure and amplitude, residual stress increases. The residual stress variation obtained from the simulation of combined turning and ultrasonic rolling closely matched the results of experimental ultrasonic rolling tests. This consistency validates the accuracy of the simulation model. This study offers a novel approach for simulating and experimentally validating ultrasonic rolling processes, particularly for shaft-like parts that undergo turning as a pre-processing step.

Two-dimensional one-way coupled modelling for fluid-structure-seabed interactions around a semicircular breakwater using OpenFOAM

Semicircular breakwaters, preferred for their lighter weight, wider base and superior resistance to overturning and sliding, have seen focused research on wave forces and hydrodynamic performance. Despite documented failures due to seabed instability, numerical examinations of the seabed response and stability around these structures are lacking in the literature. This study establishes an OpenFOAM model to numerically investigate hydrodynamic interactions, structural dynamics, seabed consolidation and liquefaction potential near a semicircular breakwater in two-dimensional, addressing complex fluid–structure-seabed interactions in a one-way coupling manner. A novel method for determining the compressibility of the pore fluid has been implemented, which integrates geostatic stress, atmospheric pressure and wave-induced excessive pore pressure within the seabed. The numerical results indicate that seabed responses are sensitive to the bulk modulus of pore air in partially saturated cases, where a decrease in pore pressure, an increase in the vertical effective stress and a decrease in the horizontal effective stress are observed. Further numerical analysis reveals that the most vulnerable part of the breakwater appears on the wave-facing side of the caisson, where reinforcement measurements are recommended during construction. A pronounced liquefaction zone is observed ahead of the breakwater, corresponding to the area with upward seepage, which is attributed to the combined effect of hydrodynamic interactions and direct stress action transferred from the semicircular breakwater.

Effects of recirculation dredging on density, strength, settling and oxygen concentration of fluid mud in the port of Emden

Abstract Purpose Recirculation dredging is a port maintenance concept developed in the Port of Emden, Germany to create a navigable fluid mud layer. This study investigates the effects of recirculation on key sediment properties, including density, yield stress, and oxygen concentration. Methods Six field monitoring surveys were carried out at two locations at different times of the year to assess changes before and after recirculation. Bathymetry, bulk density, yield stress, and oxygen concentration profiles were measured in situ. The settling properties and oxygen concentration levels on collected fluid mud samples were analyzed in the laboratory. Results The investigation reveals minimal changes in the density of recirculated fluid mud. However, the post-recirculation measurements showed a decrease in yield stress, ranging from 18 to 51% at Große Seeschleuse (GS) and 36% to 52% at Industriehafen (IH). The yield stress and density vary depending on the frequency of dredging. After structural density (1166 kg m−3 in GS and 1173 kg m−3 in IH), the yield stress of fluid mud increased exponentially. Therefore, monitoring of the yield stress is important for recirculation. A slight increase in oxygen concentration was observed post-recirculation, especially during winter. Yet, the rapid decline in oxygen levels post-mixing in the laboratory showed that sustaining long-term elevated oxygenation levels is not feasible by recirculation dredging alone. Conclusions The findings highlight the effectiveness of the recirculation on the yield stress, density, and oxygen concentration of fluid mud and illustrate the importance of considering both density and yield stress in sediment management practices. Future research should address the temporal evolution of density, yield stress, and oxygen levels following a dredging intervention and the influence of extracellular polymeric substances (EPS) and organic matter decay on sediment behavior.

Comparison of cortisol, depression and stress hormone levels in primary dysmenorhore adolescents with the application of a combination of facial acupressure with classic music therapy

&lt;p&gt;&lt;strong&gt;Background :&lt;/strong&gt;&lt;em&gt; Constant chronic dysmenorrhea pain, should be screened with a single morning serum cortisol concentration. Uncontrolled pain (acute and chronic) initially indicates high serum cortisol concentrations. Then, one of the factors that can influence pain during menstruation is stress. &lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Objectives :&lt;/strong&gt;&lt;em&gt; This study aims to assess non-pharmacological interventions for facial acupressure (BL-2, Yin Tang, GV 23, GB 15, Tai Yang, GB 14, Ex Hn4, TE 23, Sang Ming , LI-20, Ex Hn 8, ST-3, Si 18, Du 26, REN 24, JiaCenjiang, SJ21, SJ17, GB-2) combined with Mozart classical music in reducing cortisol levels, depression and stress in dysmenorrhea primary. &lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt;&lt;em&gt; This is quantitative research with a quasi-experimental design. The research approach used is pre-post test design. In November 2021-January 2022 at Megarezky University Makassar. There were 42 Adolescents with Primary Dysmenorrhea for respondents to this research. The sample in this study was divided into three groups, namely an intervention group (combination of facial acupressure with classical music) and 2 control groups which were only given classical music and facial acupressure treatment. Data collected included depression and stress. In addition, cortisol levels were checked using an ELISA Kit. Then the data was analyzed using the Paired T-test, while to see the differences if it was normally distributed using the One Way Anova test and if it was not normally distributed using Kruskal-Wallis. &lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt;&lt;em&gt; The results of the study found that there was a decrease in cortisol levels, depression and stress when given facial acupressure and classical music, but the reduction was more effective if a combination of facial acupressure and classical music.&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;&lt;/em&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt;&lt;em&gt; Among the variables of cortisol levels, depression and stress, the combination of facial acupressure and classical music was significantly more effective in improving stress than just giving facial acupressure and classical music. &lt;/em&gt;&lt;/p&gt;

Effect of Er on the Hot Deformation Behavior of the Crossover Al3Zn3Mg3Cu0.2Zr Alloy

The effect of an erbium alloying on the hot deformation behavior of the crossover Al3Zn3Mg3Cu0.2Zr alloy was investigated in detail. First of all, Er increases the solidus temperature of the alloy. This allows hot deformation at a higher temperature. The precipitates resulting from the Er alloying of the Al3Zn3Mg3Cu0.2Zr alloy were analyzed using transmission electron microscopy. Erbium addition to the alloy produces the formation of more stable and fine L12-(Al3(Zr, Er)) precipitates with a size of 20–60 nm. True stress tends to increase with a decline in the temperature and an increase in the deformation rate. The addition of Er leads to decreases in true stress at the strain rates of 0.01–1 s−1 due to particle-stimulated nucleation softening mechanisms. The effective activation energy of the alloy with the Er addition has a lower value, enabling an easier hot deformation process in the alloy with an elevated volume fraction of the intermetallic particles. The addition of Er increases the strain rate sensitivity, which makes the failure during deformation less probable. The investigated alloys have a significant difference in the dependence of the activation volume on the temperature. The flow instability criterion allows better deformability of Er-doped alloys and enables the alloys to be formed more easily. The evenly distributed particles prevent the formation of shear bands with elevated storage energy and decrease the probability of crack initiation during the initial stages of hot deformation when only one softening mechanism (dynamic recovery) is working. The microstructure analysis proves that dynamic recovery is the main softening mechanism.

Assessment of the Impact of Bone Quality and Abutment Configuration on the Fatigue Performance of Dental Implant Systems Using Finite Element Analysis (FEA).

The aim of this study was to evaluate the influence of abutment angulation, types, and bone quality on fatigue performance in dental implant systems. Three-dimensional models of maxillary 3-unit fixed implant-supported prostheses were analyzed. Abutments with different angles and types were used. Healthy bone (Hb) and resorbed bone (Rb) were used. Conducted on implants, a force of 150 N was applied obliquely, directed from the palatal to the buccal aspect, at a specific angle of 30 degrees. The stress distribution and fatigue performance were then evaluated considering the types of bone used and the angles of the three different abutments. The simulation aspect of the research was carried out utilizing Abaqus 2020 software. In all models, fatigue strengths in healthy bone were higher than in resorbed bone. Maximum stress levels were seen in models with angled implants. In almost all models with resorbed bone, fatigue performances were slightly lower. Increasing the abutment angle has been shown to increase stress levels and decrease fatigue performance in the adjacent bone and along the implant-abutment interface. In general, implants applied to healthy bone were found to have a higher success rate. It has also been suggested that multiunit abutments have beneficial effects on stress distribution and fatigue performance compared to resin cemented abutments. The type or angle of abutment and the quality of the bone can lead to biomechanical changes that affect the force distribution within the bone structure surrounding the implant. Clinicians can influence the biomechanical environment of the implant site by varying the abutment angle and type to suit the condition of bone health, potentially affecting the long-term success of implant treatment.

Mechanism of three-body abrasive grain grinding on GaN textured surfaces under uniform acceleration and variable depth

In this study, molecular dynamics (MD) was used to simulate the three-body grinding process on the textured surfaces of gallium nitride (GaN) and to investigate the effect of the processing parameters during the grinding process on the quality of the process and the removal mechanism of the material. The results show that the friction coefficient, normal force, tangential force, grinding temperature and potential energy increase with the increase of the accelerated interval segment, while the stress, subsurface damage depth and dislocation length decrease. Overall, higher speed value classes in the GaN grinding process are favorable for improving the surface finish quality. In addition, under the conditions of variable depth machining, with the increase of rising speed, the coefficient of friction, the tangential force, the normal force, the potential energy increase, the grinding temperature increases, the stress decreases, and the subsurface damage of the workpiece and the nucleation of dislocations are also significantly reduced, and the surface finish quality and the surface integrity of the workpiece are improved. The textured surfaces is an innovation in GaN processing.