Stress Profiles Research Articles

Influence of particle density on turbulence characteristics over a rough surface

The objective of the study is to use a 3D Acoustic Doppler Velocimeter (ADV) to gauge the typical flow and turbulence characteristics within a non-uniform open channel. The findings of experimental examinations of the subcritical flow along the channel are presented in this work. The behavior of sand grains in turbulent open channel flow across porous and rough bed surfaces was examined in laboratory research, and the results were obtained. The properties of turbulent flow, i.e., turbulence intensity, turbulent kinetic energy, and Reynolds shear stresses, are determined from ADV data. The continuity equation and the Reynolds equation of open-channel flow have been used to build theoretical formulations for the velocity distribution and Reynolds stress distribution in the vertical direction. Measured profiles of vertical velocity and Reynolds stress are compared to the derived expressions. The impact of the size of particles on the distribution of mean flow characteristics is discussed. This work provides a novel origin for the profile and analyzes the behavior of the vertical velocity distribution in the region where fully formed turbulence is dominating in open channels using the Navier–Stokes equations. In comparison to other sand roughness, Chopan sand bed (with greater density) exhibits the strongest turbulence intensities in both vertical and streamwise direction just next to the bed when away from the channel boundary. In contrast to flow across a rough surface, the variance ranges between 150 and 250% concerning the channel bed’s roughness type, impacting the velocity triple products that signifies transfer of turbulent kinetic energy.

Upregulation of ACSL, ND75, Vha26 and sesB genes by antiepileptic drugs resulted in genotoxicity in drosophila.

Clobazam (CLB) and Vigabatrin (VGB) are commonly used antiepileptic drugs (AEDs) in the treatment of epilepsy. Here, we have examined the genotoxic effect of these AEDs in Drosophila melanogaster. The Drosophila larvae were exposed to different concentrations of CLB and VGB containing food media. The assessment encompassed oxidative stress, DNA damage, protein levels, and gene expression profiles. In the CLB-treated group, a reduction in reactive oxygen species (ROS) and lipid peroxidation (LPO) levels was observed, alongside increased levels of superoxide dismutase (SOD), catalase (CAT), and nitric oxide (NO). Conversely, the VGB-treated group displayed contrasting results, with increased ROS and LPO and decreased SOD, CAT, and NO levels. However, both CLB and VGB induced DNA damage in Drosophila. Proteomic analysis (SDS-PAGE and OHRLCMS) in the CLB and VGB groups identified numerous proteins, including Acyl-CoA synthetase long-chain, NADH-ubiquinone oxidoreductase 75kDa subunit, V-type proton ATPase subunit E, ADP/ATP carrier protein, malic enzyme, and DNA-binding protein modulo. These proteins were found to be associated with pathways like growth promotion, notch signaling, Wnt signaling, neuromuscular junction (NMJ) signaling, bone morphogenetic protein (BMP) signaling, and other GABAergic mechanisms. Furthermore, mRNA levels of ACSL, ND75, Vha26, sesB, and Men genes were upregulated in both CLB and VGB-treated groups. These findings suggest that CLB and VGB could have the potential to induce genotoxicity and post-transcriptional modifications in humans, highlighting the importance of monitoring their effects when used as AEDs.

The Influence of Atorvastatin Treatment on Homocysteine Metabolism and Oxidative Stress in an Experimental Model of Diabetic Rats

Objective: In our experimental study, we evaluated the influence of treatment with atorvastatin on the antioxidant activity of intracellular and extracellular systems factors, homocysteine levels (Hcy), and lipid profiles in obese and diabetic rats. Method: Twenty-one male Wistar rats, aged 6 months, 450–550 g, were allocated into three groups. From the beginning of the study, the first group (G-I, control) received only standard food, while the second and third groups (G II—obese, G III—diabetic) were administered a high-fat diet (HFD) with 2% cholesterol. After 2 weeks of accommodation, the specimens in G-III were injected intraperitoneal (i.p.) streptozotocin (35 mg of body weight, pH 4.5), intervention followed by the onset of type 2 diabetes mellitus. Following confirmation of diabetes onset, the specimens in G III were administered concomitantly with the HFD a daily gavage of atorvastatin 20 mg of body weight/day for 20 days. We measured, at the beginning and the end of the study, the Hcy levels, lipid profile, vitamin B12, B6, folic acid, and various parameters of oxidative stress (OS)—total antioxidant status (TAS), glutathione peroxidase (GPX) and superoxide dismutase (SOD). Results: After treatment with atorvastatin, the lipid profile in G III significantly improved compared to the other two groups, but enzymatic markers of oxidative stress did not closely parallel this trend. However, after the treatment of statin, we observed an important reduction in Hcy values. Conclusion: Our results demonstrate that treatment with atorvastatin can be used not only for its lipid-lowering properties and antioxidant effects but also to reduce Hcy concentration in this experimental model of diabetic rats. Moreover, atorvastatin therapy improves lipid profiles, reduces inflammation, suppresses oxidation, and decreases Hcy levels, potentially preventing major adverse cardiovascular events.

Deployment stressors, mental health outcomes, and protective factors among wives of reserve soldiers during the Israel-Hamas War: A latent profile analysis approach.

Deployment to active conflict zones significantly affects military families, with spouses often experiencing heightened stress and mental health challenges. However, research on non-US military spouses, particularly those of reserve soldiers, who may face unique stressors compared to active-duty personnel, remains scarce. This study examined perceived stress profiles among Israeli spouses of reserve soldiers during the ongoing Israel-Hamas War, and their associations with deployment stressors, mental health outcomes, and psychological protective factors. A volunteer sample of Israeli spouses of reserve soldiers (n=293) responded to self-report questionnaires in a cross-sectional study. Using latent profile analysis of the ratings of perceived stress, three distinct profiles were identified: low (35.1%), moderate (43.5%), and high (21.3%). Higher levels of deployment stressors (e.g., fear of spouse getting physically injured) predicted membership in the moderate and high-stress profiles, while better household management was associated with lower stress profiles. The high-stress profile reported significantly greater symptoms of depression and anxiety compared to the low and moderate stress profiles. In contrast, the low-stress profile exhibited higher levels of resilience, self-compassion, and perceived social support. These findings highlight the variability in spouses' stress responses during wartime deployment and identify key factors associated with psychological adjustment. Results suggest that deployment-related fears, household management abilities, and psychological resources are crucial in shaping stress profiles and mental health outcomes among military spouses.

Evaluation of thiol/disulphide and oxidant-antioxidant status of dairy cows in periparturient and post-partum period.

Thiol/disulphide homeostasis (TDH) has a critical role in many cellular activities such as antioxidant protection. Alterations of oxidative stress in the transition period play an important role in development of some diseases and disorders in dairy cows. The purpose of this study is to assess the total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), total thiol, native thiol, disulphide and lipid profile in Simmental and Montofon dairy cows (aged 2-3) before and after calving. Blood samples were collected 233-280 days of pregnancy and the 30 days of post-partum. Serum total thiol, native thiol and disulphide levels were determined as well as TAS, TOS and paraoxonase-1 (PON-1) levels were measured using colorimetric assays. Triglycerides (TG), total cholesterol, HDL cholesterol and LDL cholesterol levels were measured with an automatic analyser. Total thiol (p=0.038) and disulphide (p=0.015) levels were higher after calving compare to pregnancy in Montofon. TAS was found lower (p<0.001), and OSI was higher in both breeds (Montofon p=0.012, Simmental p=0.028) after calving than in pregnancy. When compared between pregnancy and after calving levels in the same breed, HDL was found to be higher after calving (p<0.001) and TG was lower after calving (p=0.020) in Montofon. PON (p=0.090), HDL (p<0.001) and cholesterol levels were found higher (p<0.001) and TG level was lower (p<0.001) after calving in Simmental. According to our results, we observed different responses between two breeds before and after calving. There are few studies about TDH in animal research, and this is the first study in the literature that evaluates the TDH along with oxidative stress and lipid profiles in dairy cows in the periparturient and post-partum period.

Shock-induced twinning/detwinning and spall failure in Cu–Ta nanolaminates at atomic scales

Abstract This study provides new insights into the role of interfaces on the deformation and failure mechanisms in shock-loaded Cu–Ta–Cu trilayer system. The thickness of the Ta layer, piston velocities, and shock pulse durations were varied to explore the impact of impedance mismatch and loading conditions on spallation behavior and twin formation. It was found that the interfaces play a crucial role in the dynamic response of these multilayered systems since secondary reflection waves generated at the interfaces significantly affected the peak stress and pressure profiles, influencing void nucleation and failure modes. In the trilayer systems, failure predominantly occurred at interfaces and within the Ta layer, with void nucleation sites and twinning behavior being markedly different compared to single-crystal Cu and Ta. Increasing the Ta layer thickness modified the wave interactions, leading to different failure locations. Higher piston velocities were associated with increased spall strength by enhancing wave interactions and void formation, particularly at the interfaces and within the Ta layer, under specific configurations. Additionally, shorter shock pulse durations facilitated earlier initiation of the release fan, reducing twin formation and altering the failure dynamics by accelerating twin annihilation and pressure release.

Effect of parenteral trace element supplementation on oxidative stress and transcriptomic profile of peripheral blood in peripartum dairy cows

Effect of parenteral trace element supplementation on oxidative stress and transcriptomic profile of peripheral blood in peripartum dairy cows

Stress profile of veterinarians in Switzerland: Young + female + employed = stressed?

The impairment of mental health among veterinary professionals has raised public awareness in recent years. The driving forces include a serious gap in veterinary services - with less available veterinary colleagues, especially in rural areas - and a general lack of veterinary graduates. This article presents the results of our first Swiss survey on psychological well-being in the veterinary profession. Our results are viewed both in the current context and in the context of developments that have already taken place in other medical disciplines. Results indicate higher levels of stress in veterinarians working as clinicians, in female colleagues, in veterinarians of younger age and veterinarians under employment. In the meantime, larger surveys such as the Vétos Entraide (https://vetos-entraide.com) were established in France and projects such as the Happy Vet project (https://happyvetproject.org) were launched in Switzerland for eg. the burnout prevention in the profession. However, the topic of «mental health» remains highly relevant in veterinary medicine and requires further research and measures, which should consider the identified predisposing factors, such as age and gender.

Sibling presence during fostering ameliorates endocrine stress profile changes in a social rodent species (Octodon degus) in a sex-specific manner

During early life, disruption of the parent-offspring bond can substantially impact development of offspring physiology and behavior. In rodents, it has been well-documented that parental separation, reduction in parental care, and cross-fostering can affect development of the endocrine stress response. For social species, however, several social factors may mitigate the stress of cross-fostering, such as remaining with other known adult caregivers or siblings. In this study, we cross-fostered a social rodent species (Octodon degus) with or without their siblings at postnatal day (PND) 8 and measured their endocrine stress response immediately after fostering (PND9) and at weaning (PND28). We found that female singly-fostered offspring displayed elevated baseline cortisol levels and reduced weight gain immediately after fostering. At weaning, female singly-fostered offspring continued to display elevated baseline cortisol levels compared to non-fostered female offspring, while singly-fostered males demonstrated weaker cortisol negative feedback strength compared to male offspring that were not fostered or were fostered with their siblings. These results suggest that sibling presence may help mitigate the stress of fostering, and that future studies should further examine other social conditions that may help reduce developmental consequences of long-term parental bond disruption.

Smartphone addiction, depression, distress, eustress, loneliness, and sleep deprivation in adolescents: a latent profile and network analysis approach

BackgroundPrevious research on adolescent smartphone addiction has tended to focus on general populations that are assumed to be homogeneous, overlooking latent profiles. Furthermore, previous research has not focused on potentially important differences in the latent profiles of adolescent smartphone addiction in networks. The present study aimed to reveal the latent profiles of smartphone addiction, depression, stress, eustress, loneliness, and sleep deprivation in adolescents, and general and latent profiles were examined in the network.MethodsThe study group consisted of 436 (222 boys and 214 girls) adolescents, aged between 13 and 18 years. The findings of the present study were provided using Pearson correlation, ANOVA, latent profile analysis and network analysis. The data were analyzed using SPSS, JASP, and Mplus.ResultsThe results of the study showed solutions with three latent profiles. The non-addicted group constituted 20.87%, the addicted group covered 29.82% and the risky group included 49.31% of the study group. Although the general profile and the addicted latent group had similar characteristics, the differences in the risky and non-addicted groups contributed to the current literature by providing a further and remarkable perspective on smartphone addiction, depression, distress, eustress, loneliness, and sleep deprivation in adolescents.ConclusionsThe theoretical and practical implications of the present results will provide contributions to researchers and practitioners in understanding smartphone addiction.

Postgraduate psychological stress detection from social media using BERT-Fused model.

Postgraduate students face various academic, personal, and social stressors that increase their risk of anxiety, depression, and suicide. Identifying cost-effective methods of detecting and intervening before stress turns into severe problems is crucial. However, existing stress detection methods typically rely on psychological scales or devices, which can be complex and expensive. Therefore, we propose a BERT-fused model for rapidly and automatically detecting postgraduate students' psychological stress via social media. First, we construct an improved BERT-LDA feature extraction algorithm to extract group stress features from large-scale and complex social media data. Then, we integrate the BiLSTM-CRF named entity recognition model to construct a multi-dimensional psychological stress profile and analyze the fine-grained feature representation under the fusion of multi-dimensional features. Experimental results demonstrate that the proposed model outperforms traditional models such as BiLSTM, achieving an accuracy of 92.55%, a recall of 93.47%, and an F1-score of 92.18%, with F1-scores exceeding 89% for all three types of entities. This research provides both theoretical and practical foundations for universities or institutions to conduct fine-grained perception and intervention for postgraduate students' psychological stress.

A new concept of structural smart fabric activated by shape memory alloys

Abstract This work presents the development, prototyping and validation of a new concept of structure called Structural Smart Fabric (SSF). An SSF is a chainmail fabric composed by interconnected elements, called cells, which can be stiffened by reactive elements, such as those made by Shape Memory Alloy (SMA). Exploiting the shape memory functionality, SSFs are capable of sensing and reacting to external stimuli. Based on this concept, in this study we propose an SSF that integrates SMA wires into a 3D-printed chainmail structure. The shape memory effect of these wires is used as an actuating mechanism that, at high temperature, tightens the adjacent cells together and provides increased structural stiffness. In this study, finite element simulations were initially conducted to enhance the comprehension of the SSF’s mechanical behaviour. The influence of the initial cell spacing on the SSF stiffness and the wire stress profiles was evaluated during bending loading, as well as the evolution of contact pressure profiles between adjacent cells. This numerical approach enabled to tune the design of the SSF prototypes which were successively manufactured using Selective Laser Sintering (SLS) additive manufacturing technology with PA12. After the integration with the SMA wires, the SSF prototypes were tested under a 3-point bending configuration at different temperatures. The results revealed a remarkable increase in structural stiffness at elevated temperatures compared to ambient conditions. This study set the basis for a deeper understanding of SSF's unique capabilities and potential applications in fields where adaptive and responsive structures are required.&amp;#xD;

Alleviation of oxidized lipid-induced oxidative stress and hypertension by estrogen and selected antihyperlipidemic drugs in post-menopausal Wistar rats

Lipid peroxidation is implicated in the development of hypertension and coronary artery disease, and its deleterious impact is exacerbated by estrogen (ETD) depletion in post-menopausal women. We hypothesize that treatment with ETD and antihyperlipidemic drugs, either alone or in combination, can alleviate the development of cardiovascular disease. In this study, female Wistar rats were divided into 10 groups (n = 6): Group 1 (control) underwent a Sham operation and was fed standard rat chow, whereas the other nine groups were ovariectomized (OVX) and received a diet containing either thermoxidized palm oil (TPO) or thermoxidized soya oil (TSO) for 12 weeks. ETD at 0.2 mg/kg/day, atorvastatin (ATV) at 10 mg/kg/day, and a combination of ezetimibe (EZE) and ATV (EZE at 3 mg/kg/day + ATV at 10 mg/kg/day) were administered for 12 weeks in both TSO and TPO diet groups. Blood pressure and electrocardiogram (ECG) parameters were assessed, along with serum lipid profile, atherogenic indices, and markers of oxidative stress. Both TPO and TSO diets significantly altered blood pressure and ECG parameters in OVX rats. Treatment with ATV, EZE+ATV, and ETD significantly reduced blood pressure parameters compared to the OVX+TPO group. Antihyperlipidemic drugs significantly decreased heart rate, QT interval, QRS duration, and QT corrected (QTc), whereas ETD similarly shortened the QRS and QTc duration. ATV and ETD also reduced total cholesterol, triglycerides, and very low-density lipoprotein levels, while boosting high-density lipoprotein concentrations compared to untreated OVX+TSO rats. This study demonstrates that thermoxidized oil has a deleterious effect on OVX rats by altering blood pressure, ECG parameters, and atherogenic indices. Treatment with antihyperlipidemic drugs and ETD normalized blood pressure and ECG parameters, reversed hyperlipidemia, and restored antioxidant system balance.

Antimutagenic and anticoagulant therapeutic effects of Ag/Ag2O nanoparticles from Olea europaea leaf extract: mitigating metribuzin-induced hepato-and nephrotoxicity.

Silver nanoparticles (Ag/Ag₂O NPs) have garnered attention for their potent antioxidant, antimicrobial, and anti-inflammatory properties, showing promise for therapeutic applications, particularly in mitigating chemical-induced toxicity. This study aimed to synthesize Ag/Ag₂O NPs using Olea europaea (olive) leaf extract as a green, eco-friendly reducing agent and evaluate their protective effects against metribuzin-induced toxicity in Wistar rats, focusing on oxidative stress, hematological parameters, and lipid profiles, with specific dose optimization. Ag/Ag₂O NPs were synthesized using Olea europaea leaf extract, and their properties were confirmed via XRD, FTIR, SEM, EDS, and UV-visible spectroscopy. Wistar rats exposed to metribuzin (110mg/kg/day) were treated with two doses of Ag/Ag₂O NPs (0.062mg/kg and 0.125mg/kg). Hematological and biochemical markers were assessed to evaluate the NPs' protective effects. Physicochemical characterization confirmed the successful formation of Ag/Ag₂O NPs loaded with phytochemicals, exhibiting crystallite sizes of 23nm and 19nm, a particle size of 25nm, and significant peaks in XRD, FTIR, and UV-Vis spectra indicating the formation of Ag/Ag₂O. Metribuzin exposure led to significant hematological disruptions (elevated WBC, reduced RBC and hemoglobin) and worsened lipid profiles (increased cholesterol, LDL, and triglycerides). The lower NP dose (0.062mg/kg) improved WBC, RBC, hemoglobin, and platelet counts, normalized lipid levels, and positively influenced biochemical markers such as serum creatinine and uric acid. In contrast, the higher NP dose (0.125mg/kg) showed mixed results, with some improvements but an increase in triglycerides and continued elevation of ASAT and ALAT enzyme levels. Ag/Ag₂O NPs synthesized via green methods using olive leaf extract effectively mitigated metribuzin-induced toxicity, especially at lower doses, by improving oxidative stress markers and hematological and biochemical profiles. Dose optimization is crucial to maximize therapeutic benefits and minimize adverse effects, underscoring their potential in treating chemical-induced toxicity.

An Integrated Machine Learning Workflow to Estimate In Situ Stresses Based on Downhole Sonic Logs and Laboratory Triaxial Ultrasonic Velocity Data

AbstractThe optimum performance of various subsurface operations such as stimulation treatments, wellbore drilling, horizontal well placement, underground mining, and tunneling rely on accurate estimation of the in situ stresses. This study presents an integrated machine learning (ML) workflow for the reliable determination of the in situ stress in subsurface rock formations. The study workflow was completed in three phases. In the first phase, six supervised ML regression techniques were employed to develop the stress prediction models using laboratory true triaxial ultrasonic velocity tests (labTUV) data of subsurface rock samples retrieved from well 16A(78)‐32 located at the Utah FORGE geothermal site. In the second phase, subsurface geological formations were classified into rock facies using an unsupervised K‐means clustering algorithm. Finally, in the third phase, the optimized ML models were employed for predicting the in situ stresses in the corresponding rock facies in the well 16A(78)‐32 using field sonic logs. A comparison of evaluation metrics revealed the superior performance of ANN models for horizontal and vertical stress predictions with root mean squared error of 1.5, 0.6, and 1.7 MPa, and determination coefficient (R2) of 0.98, 0.98, and 0.96, for the testing/validation phases, respectively. The generalization capability of ML models was explored by uncovering the underlying physics. The mathematical expressions of constitutive relations were extracted from three ANN models. Further, a total of five rock facies were identified in the subsurface geological formations. The novel workflow would be capable of delivering reliable in situ stress profiles in subsurface geological formations without performing expensive field tests.

Healthy plasma lipidomic signatures depend on sex, age, body mass index, and contraceptives but not perceived stress.

Perceived stress is thought to contribute to the pathogenesis of metabolic, vascular, mental, and immune diseases, with different susceptibilities in women and men. The present study investigated if and how perceived stress and/or demographic variables including sex, age, body mass index, regular prescription drugs, occasional analgesics, or dietary supplements manifested in plasma lipidomic profiles, obtained by targeted and untargeted mass spectrometry analyses. The study included 217 healthy women and 108 healthy men, aged 18-68 years, who were recruited in a 2:1 female:male ratio to account for women with/without contraceptives. As expected, dehydroepiandrosterone sulfate (DHEAS) and ceramides were higher in men than women, and DHEAS decreased with age, while ceramides increased. Contrary to expectations, neither DHEAS nor ceramides were associated with perceived stress (PSQ30 questionnaire), which was however, associated with BMI in men, but not in women. None of the lipid species or classes showed a similar "age X sex X BMI" interaction, but the endocannabinoid palmitoylethanolamide (PEA) correlated with BMI and hypertension. Independent of perceived stress, lysophosphatidylcholines (LPCs) were lower in women than men, whereas LPC metabolites, lysophosphatidic acids (LPAs), were higher in women. The LPA:LPC ratio was particularly high in women using oral contraceptives suggesting a strong hormone-induced extracellular conversion of LPCs to LPAs, which is catalyzed by the phospholipase D, autotaxin. The results reveal complex sex differences in perceived stress and lipidomic profiles, the latter being exacerbated by contraceptive use, but perceived stress and lipids were not directly correlated.

The impact of finite span and wing-tip vortices on a turbulent NACA0012 wing

High-fidelity simulations are conducted to investigate the turbulent boundary layers around a finite-span NACA0012 wing with a rounded wing-tip geometry at a chord-based Reynolds number of $Re_c=200\,000$ and at various angles of attack up to $10^\circ$ . The study aims to discern the differences between the boundary layers on the finite-span wing and those on infinite-span wings at equivalent angles of attack. The finite-span boundary layers exhibit: (i) an altered streamwise and a non-zero spanwise pressure gradient as a result of the variable downwash induced by the wing-tip vortices (an inviscid effect typical of finite-span wings); (ii) differences in the flow history at different wall-normal distances, caused by the variable flow angle in the wall-normal direction (due to constant pressure gradients and variable momentum normal to the wall); (iii) laminar flow entrainment into the turbulent boundary layers near the wing tip (due to a laminar–turbulent interface); and (iv) variations in boundary layer thickness across the span, attributed to the variable wall-normal velocity in that direction (a primarily inviscid effect). These physical effects are then used to explain the differences in the Reynolds stress profiles and other boundary layer quantities, including the reduced near-wall peak of the streamwise Reynolds stress and the elevated Reynolds stress levels near the boundary layer edge, both observed in the finite-span wings. Other aspects of the flow, such as the downstream development of wing-tip vortices and their interactions with the surrounding flow, are reserved for future investigations.

Nitric Oxide-Dependent Regulation of Oxygen-Related Processes in a Rat Model of Lead Neurotoxicity: Influence of the Hypoxia Resistance Factor

Background/Aims: Lead exposure is known to induce oxidative stress and neurotoxicity. Nitric oxide (NO) plays an important role in modulating oxidative stress, with L-arginine as a precursor of NO and Nω-nitro-L-arginine (L-NNA) as an inhibitor of NO synthase, an enzyme that catalyses the production of nitric oxide (NO) from L-arginine. Methods: This study investigated the differential effects of L-arginine and L-NNA on markers of oxidative stress and biochemical changes in brain tissue from rats with different levels of resistance to hypoxia exposed to lead nitrate. Rats with either low or high resistance to hypoxia were exposed to lead nitrate (oral 3.6 mg lead nitrate/kg b.w. per day for 30 days) and treated with L-arginine (600 mg/kg b.w., i.p., 30 min before and after exposure to lead nitrate) or L-NNA (35 mg/kg b.w., i.p., 30 min before and after exposure to lead nitrate). Brain tissue samples were analysed for lipid peroxidation, oxidative modification of proteins, and activity of antioxidant enzymes, including superoxide dismutase, catalase, glutathione reductase, and peroxidase, and total antioxidant status (TAS). We also examined the biomarkers of biochemical pathways involving the activity of alanine and aspartate aminotransferases, succinate dehydrogenase (SDH), and α-ketoglutarate dehydrogenase (KGDH). In addition, the trend observed was supported by assessments of the acetylcholine levels and acetylcholinesterase activity (ACh-AChE system) in brain tissue. Results: In rats with low resistance to hypoxia, the L-arginine treatment significantly reduced lipid peroxidation and oxidative protein modification but increased antioxidant enzyme activity, suggesting a protective effect against lead-induced oxidative stress. Conversely, in rats with high resistance to hypoxia, L-NNA had a protective effect, reducing lead-induced oxidative damage and decreasing lipid peroxidation, whereas L-arginine exacerbated oxidative stress and impaired antioxidant defences. These findings were supported by corresponding changes in the acetylcholine-acetylcholinesterase system, reflecting the observed patterns of lead-induced oxidative stress and neurotoxicity. The study shows that L-arginine exerts a protective effect by reducing lead-induced oxidative damage via an improvement in TAS. Our study shows that lead nitrate exposure significantly increases ala-nine and aspartate aminotransferase activity in brain tissue, with L-arginine exacerbating and L-NNA reversing this effect. The lead nitrate exposure also affected the activities of SDH and KGDH, which are important for cellular energy production and hypoxia resistance, with L-arginine altering SDH activity depending on the level of resistance and L-NNA enhancing both SDH and KGDH activities. These trends were further validated by alterations in the ACh-AChE system, highlighting the differential role of NO-dependent mechanisms in modulating lead-induced neurotoxicity based on hypoxia resistance. Conclusion: These findings suggest potential targeted therapeutic strategies based on the oxidative stress profile and highlight the potential of nitric oxide system modulators in counteracting lead-induced biochemical alterations and the dynamics of the ACh-AChE system depending on the individual physiological reactivity of organisms.

Geomechanical modeling aspects in support of hydraulic fracturing operations

This paper describes the main aspects and nuances of geomechanical modeling that must be considered when supporting hydraulic fracturing operations and providing engineering support of projects. A key feature of geomechanical modeling for hydraulic fractures aims or self-induced fracturing in mature fields is the estimation of reservoir pressure, particularly in the vicinity of production and injection wells. In addition, this has a significant impact on stress anisotropy, which is the primary factor affecting the geometry of the hydraulic fracture and the surrounding induced stress field. It is also crucial to monitor geomechanical core studies, ensure quality control of samples, and accurately process research results since the profiles of elastic-strength properties and stresses depend on these factors. This paper also addresses fracturing, including its measurement, calculations, and the prediction of its spatial orientation and intensity.

Analysis of Wind Power Fluctuation in Wind Turbine Wakes Using Scale-Adaptive Large Eddy Simulation

In large wind farms, the interaction of atmospheric turbulence and wind turbine wakes leads to complex vortex dynamics and energy dissipation, resulting in reduced wind velocity and subsequent loss of wind power. This study investigates the influence of vortex stretching on wind power fluctuations within wind turbine wakes using scale-adaptive large eddy simulation. The proper orthogonal decomposition method was employed to extract the most energetic contributions to the wind power spectra. Vertical profiles of mean wind speed, Reynolds stresses, and dispersive stresses were analyzed to assess energy dissipation rates. Our simulation results showed excellent agreement when compared with wind tunnel data and more advanced numerical models, such as the actuator line model and the actuator line model with hub and tower effects. This highlights the important role of coherent and energetic flow components in the spectral behavior of wind farms. The findings indicate a persistent energy cascading length scale in the wake of wind turbines, emphasizing the vertical transport of energy to turbine blades. These results complement existing literature and provide new insights into the dynamics of wind turbine wakes and their impact on wind farm performance.