Extra Stress Research Articles

Non-affine motion and selection of slip coefficient in constitutive modeling of polymeric solutions using a mixed derivative

Constitutive models for the dynamics of polymer solutions traditionally rely on closure relations for the extra stress or related microstructural variables (e.g., conformation tensor) linking them to flow history. In this work, we study the eigendynamics of the conformation tensor within the GENERIC framework in mesoscopic computer simulations of polymer solutions to separate the effects of nonaffine motion from other sources of non-Newtonian behavior. We observe that nonaffine motion or slip increases with both the polymer concentration and the polymer chain length. Our analysis allows to uniquely calibrate a mixed derivative of the Gordon–Schowalter type in macroscopic models based on a micro-macromapping of the dynamics of the polymeric system. The presented approach paves the way for better polymer constitutive modeling in multiscale simulations of polymer solutions, where different sources of non-Newtonian behavior are modelled independently.

Thermal super-jogs control the high-temperature strength plateau in Nb-Mo-Ta-W alloys

Refractory multi-element alloys (RMEA) with body-centered cubic (bcc) structure have been the subject of much research over the last decade due to their high potential as candidate materials for high-temperature applications. Most of these alloys display a remarkable strength at temperatures above 1000 ∘C, which cannot be explained by the standard model of bcc plasticity dominated by thermally-activated screw dislocation motion. Recent research on Nb-Mo-Ta-W alloys points to a heightened role of edge dislocations during mechanical deformation, which is generally attributed to atomic-level chemical fluctuations in the material and their interactions with dislocation cores during slip. However, while this effect accounts for levels of strength that are larger than what might be found in a pure metal, it is not sufficient to explain the high yield stress found at elevated temperatures, particularly in the so-called strength ‘plateau’ region. In this work, we propose a strengthening mechanism based on the existence of thermal super-jogs in edge dislocations that act as strong obstacles to dislocation motion. The basis for the formation of these super-jogs is found in the unique properties of RMEA, which display vacancy formation energy distributions with tails that extend to almost zero energy. This facilitates vacancy formation at dislocation cores, which subsequently relax into atomic-sized super-jogs. While these super-jogs result in alloy strengthening in a wide temperature range, they can also displace diffusively along the glide direction, relieving with their motion some of this extra stress and eventually leading to strength softening above 2000 K. We implement these mechanisms into a specially-designed hybrid kinetic Monte Carlo/Discrete Dislocation Dynamics approach (kMC/DD) parameterized with vacancy formation and migration energy distributions obtained with machine-learning potentials designed specifically for the Nb-Mo-Ta-W system. The kMC module sets the timescale dictated by thermally-activated events, while the DD module relaxes the dislocation line configuration in between events in accordance with elastic forces and the applied stress. We find that the balance between super-jog pinning and super-jog diffusion confers an extra strength to edge dislocations at intermediate-to-high temperatures which is consistent with the experimental observation of a strength plateau in equiatomic Nb-Mo-Ta-W. We derive an analytical model based on the computational results that captures this improved understanding of plastic processes in these alloys and could help to partially explain the strength measurements at high temperatures.

Daily stress, family functioning and mental health among Palestinian couples in Israel during COVID-19: A moderated mediation model.

The COVID-19 pandemic created a range of stressors, among them difficulties related to work conditions, financial changes, lack of childcare, and confinement or isolation due to social distancing. Among families and married individuals, these stressors were often expressed in additional daily hassles, with an influence on mental health. This study examined two moderated mediation models based on Bodenmann's systemic-transactional stress model. Specifically, the models tested the hypothesis that intra-dyadic stress mediates the association between extra-dyadic stress and mental health, while two measures of family functioning, cohesion and flexibility, moderate the relationship between extra and intra-dyadic stress. Participants were 480 Palestinian adults in Israel who completed self-report questionnaires. All were in opposite-sex marriages and identified as either cisgender women or cisgender men. The results showed partial mediation patterns supporting both models, indicating that family cohesion and flexibility weakened the mediating effect of intra-dyadic stress on the relationship between extra-dyadic stress and mental health. These findings increase our understanding of the variables that affected mental health during the pandemic, and suggest that when faced with extra-dyadic stress, married individuals with good family environments are less likely to experience high levels of intra-dyadic stress, which is in turn associated with preserved mental health. Limitations and implications for planning interventions for couples and families during the pandemic are discussed.

Network exploration of gene signatures underlying low birth weight induced metabolic alterations.

This study explored underlying gene signatures of low birth weight (LBW) by analyzing differentially expressed genes (DEGs) between LBW and normal birth weight (NBW) subjects. Subjects with different birth weight was collected from GEO database. P < .05 and | logFC | ≥ 1.0 were used for screening DEGs. David (2021 Update) was used to perform GO annotation and KEGG signaling pathway enrichment analysis. The protein-protein interaction network of DEGs was constructed using the STRING database, in which hub genes were mined through Cytoscape software. A total of 326 DEGs were identified, including 287 up-regulated genes and 39 down-regulated genes. The GO biological processes enriched by DEGs mainly involved epidermal growth, keratinization and intermediate fibrous tissue. The DEGs were significantly enriched in intracellular insoluble membranes, desmosomes and extracellular space. Their molecular functions mainly focused on structural molecular activity, structural components of epidermis and structural components of cytoskeleton. PI3K/AKT signaling pathway and tight junction were highlighted as critical pathways enriched by DEGs. Ten hub genes which included KRT14, EGF, DSP, DSG1, KRT16, KRT6A, EPCAM, SPRR1B, PKP1, and PPL were identified from the constructed protein-protein interaction network. A total of 326 DEGs and 10 hub genes were identified as candidates for metabolic disorders in LBW individuals. Our results indicated PI3K/AKT signaling pathway as an intrauterine adaptive mechanism for LBW individuals. We observed activated PI3K/AKT pathway in LBW individuals, which would promote growth and development at the early stage of life, but adversely introduce extra metabolic stress and thereby potentially induce metabolic disorders in adulthood.

Arteriovenous Fistulae in Chronic Kidney Disease and the Heart: Physiological, Histological, and Transcriptomic Characterization of a Novel Rat Model.

Background Arteriovenous fistulae (AVFs) are the gold standard for vascular access in those requiring hemodialysis but may put an extra hemodynamic stress on the cardiovascular system. The complex interactions between the heart, kidney, and AVFs remain incompletely understood. Methods and Results We characterized a novel rat model of five-sixths partial nephrectomy (NX) and AVFs. NX induced increases in urea, creatinine, and hippuric acid. The addition of an AVF (AVF+NX) further increased urea and a number of uremic toxins such as trimethylamine N-oxide and led to increases in cardiac index, left and right ventricular volumes, and right ventricular mass. Plasma levels of uremic toxins correlated well with ventricular morphology and function. Heart transcriptomes identified altered expression of 8 genes following NX and 894 genes following AVF+NX, whereas 290 and 1431 genes were altered in the kidney transcriptomes, respectively. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis revealed gene expression changes related to cell division and immune activation in both organs, suppression of ribosomes and transcriptional activity in the heart, and altered renin-angiotensin signaling as well as chronodisruption in the kidney. All except the latter were worsened in AVF+NX compared with NX. Conclusions Inflammation and organ dysfunction in chronic kidney disease are exacerbated following AVF creation. Furthermore, our study provides important information for the discovery of novel biomarkers and therapeutic targets in the management of cardiorenal syndrome.

Electrokinetic peristaltic bioconvective Jeffrey nanofluid flow with activation energy for binary chemical reaction, radiation and variable fluid properties

AbstractThis paper aims to present a comprehensive study of the non‐linear peristaltic transport within a vertical uniform/non‐uniform channel filled with a Jeffery non‐Newtonian nanofluids in the presence of oxytactic microorganisms. The thermal conductivity of the used physiological fluids is varied linearly with the temperature while Arrhenius function is applied for the activation energy. The significance of electrical and magnetic fields together with a linear radiation and viscous dissipation are analyzed. The flow and heat transfer analysis has been performed under wall slip and compliant conditions. Additionally, optimization of the system entropy under the impacts of these aspects is examined. Numerical solutions for the governing system are introduced and profiles of the velocity u, temperature θ, nanoparticle distributions φ, heat transfer coefficient z and extra stress tensor distribution for the variations of the considered parameters are discussed. The main outcomes revealed that the maximizing of the Brinkman number is better to get higher features of the extra stress tensor . Also, the velocity u, density of the microorganisms ξ and the NP distributions in the interval get lower features as is altered. However, the temperature distributions are maximized as is growing.

Maternal Stress and Neonatal Nutrition during the COVID-19 Era.

COVID-19 pandemic has put a tremendous amount of stress on people, which can negatively affect nursing. Previous studies showed that perceived stress and cortisol levels in the postpartum period correlate with the LATCH scores, which is a simple tool to assess the pattern of nursing. Likewise, greater prenatal anxiety was associated with a shorter breastfeeding duration. We aimed to evaluate whether pregnant women were under extra stress due to the COVID-19 pandemic and if this stress affected their breastfeeding patterns and anthropometric measures of the neonates. Pregnant women giving birth to healthy neonates were included. Coronavirus Anxiety Scale (CAS) and Beck Anxiety Inventory (BAI) were used to assess the anxiety levels of the mothers, and LATCH breastfeeding assessment tool was used to assess the nursing. The results of these scales and anthropometric measures of the neonates were recorded. Only one mother showed coronavirus-specific anxiety. Therefore, further analysis was done based on the Beck Anxiety (BA) levels of the mothers. CAS and BA scores were positively correlated (p<0.001, r=0.444), indicating that coronavirus-specific anxiety increased with increasing general anxiety. None of the variables changed depending on the anxiety levels of the mothers, except for the % weight gain at day five (p=0.020, r=-0.248). Even though anxiety seemed to show a small effect on weight loss during the first neonatal days, percent weight gain results did not seem to correlate with the anxiety levels in later stages (first month of life). Furthermore, LATCH scores of the infants on day one were positively correlated with BA scores of the mothers (p=0.045, r=0.175). COVID-19 seemed to have no additional effect on the stress levels of the mothers. The more the mothers have anxiety, the more they may stress about the well-being of their infants, which can improve their nursing pattern.

DC-Link voltage control of a multifunctional PV-GCVSI to reduce VSI switching losses

ABSTRACT The reference input dc voltage of grid connected voltage source inverter (GCVSI) is altered in this article based on power (both active and reactive) injection from GCVSI for minimising inverter switching losses, and total harmonic distortion (THD) of grid current. If the GCVSI is exclusively used for actual power injection from the photo-voltaic (PV) system to the utility grid, the needed input dc voltage of GCVSI is twice the utility grid phase peak voltage. According to the literature, GCVSI is also used to compensate for power quality issues, and in these circumstances, the dc-link voltage value is determined by the maximum power injection of GCVSI. Under reduced load, and reduced power generation from the PV system, keeping maximum GCVSI input dc voltage reference causes extra voltage stress at GCVSI switches, and the grid current THD is worse due to high ripple current in filter inductance. Therefore, to reduce the inverter switching losses and to improve the grid current THD, the relationship between the GCVSI input dc voltage reference and the power flow from GCVSI has been formulated. The proposed work is verified using simulation studies, as well as hardware studies, and the results are compared with existing methods for validation.

The Impact of Stress on Innovative Work Behavior among Medical Healthcare Professionals.

Background: For health systems, a fundamental challenge is adapting to changes in the patterns of health services that require technological and scientific innovations. The pace of multiple and interconnected challenges mounts extra stress on medical healthcare professionals and reduces their innovative capabilities, especially in low- and middle-income countries. To enhance the innovative capability of medical healthcare professionals under stress, the study seeks any possible correlation between stress and innovation. For that purpose, we sought to investigate the effects of stress on the innovative work behavior of employees and examine the mediating effect of health and moderating effect of supervisor support. Materials and Methods: 350 medical healthcare professionals were surveyed in different hospitals in Lahore through a survey regarding stress, health, innovative work behavior, and supervisor support with a final response rate of 89%. SPSS and AMOS were used for the analysis of the data and the investigation of the combined effects of the model. Exploratory (EFA) and Confirmatory Factor Analysis (CFA) were conducted to ensure the convergent and discriminant validity of the factors, while mediation analysis was done to check the mediating role of health. Results: It has been observed that there is partial mediation of health between eustress and innovative work behavior whereas supervisor support does not moderate between eustress and health. Furthermore, the results indicate that distress is negatively associated with innovative behavior. In addition, health fully mediates between distress and innovative work behavior. If distress increases negative effects on health, then supervisor support reduces the negative impact of distress on health. Furthermore, supervisor support also reduces the negative impact of health on innovative work behavior. Conclusion: Our study outlines a hypothetical alternative situation that explains how the two emotions of eustress and distress are brought into play in the innovative work behavior of the employees. In addition, supervisors play an important role in influencing the sustainable innovation work behavior of their staff members.

Dynamic compressive response of porcine muscle measured using a split Hopkinson bar system with a pair of PVDF force transducers

The classic metallic Split Hopkinson Pressure Bar (SHPB) cannot capture the transmitted signal accurately when measuring soft biological tissue, because of the very low wave impedance and strength of this material. So the dynamic compressive response of porcine muscle has been investigated by using a modified SHPB. The forces on both ends of the sample measured using Polyvinylidene fluor (PVDF) transducers were applied to calculate the stress in the specimen instead of the strain gauge signal on the transmitted bar. Moreover, a circular cardboard disk pulse shaper was applied for generating a suitable incident pulse to achieve stress equilibrium and constant strain rates in the specimens. Then, the dynamic mechanical properties of porcine muscle parallel and perpendicular to the fiber directions were measured, and the stress equilibrium process during loading was analyzed, as well as the inertia-induced extra stress being corrected. Furthermore, quasi-static tests were conducted at two different strain rates to investigate the strain rate dependence using a universal material testing machine. The results show that the stress-strain curves are sensitive to strain rate in the two different loading directions. The compressive stress perpendicular to the fiber direction is stiffer than that parallel to the fiber direction. In addition, a strain rate-dependent constitutive model was developed based on the mechanical response of the muscle at different strain rates and fitted to the experimental data. The results show that the overall fit is good, and the constitutive model could describe the muscle's dynamic mechanical properties.

Physiological and morphological responses of Chlorella pyrenoidosa to different exposure methods of graphene oxide quantum dots

Graphene oxide quantum dots (GOQDs) can convert the ultraviolet (200– 380 nm) into available wavelength (400– 700 nm) for microalgae cultivation. However, it has not been applied in large-scale microalgae culture due to its high cost and difficulties in recovery. This study proposed a new strategy for the sustainable use of GOQDs, namely, GOQDs solution was added to the outer sandwich of the reactor. Herein, the effects of direct and indirect exposure of different GOQDs concentrations (0, 100, and 1000 mg/L) on the microalgae culture were compared. When microalgae were directly exposed to the GOQDs, 100 mg/L of GOQDs increased the biomass production of microalgae by 24.0 %, while 1000 mg/L of GOQDs decreased biomass production by 31 %. High concentration of GOQDs (direct exposure) could cause extra oxidative stress in the microalgae cells and result in a significant reduction of pigment content. When microalgae were indirectly exposed to the GOQDs, the increased concentration of GOQDs enhanced the growth of microalgae. Compared to the blank group, 1000 mg/L of GOQDs increased the microalgae biomass production and bioenergy by 14.1 % and 40.17 %, respectively. The indirect exposure of GOQDs can effectively avoid photo-oxidation and organelle damage to the microalgae cells. Overall, the indirect exposure of GOQDs is a sustainable way for effectively promoting microalgae growth and reducing the application cost.

An exploration of polymer presence in magneto‐hydrodynamic flow and heat transfer past a magnetized stretching surface with effects of Joule heating

AbstractThe consequences of polymer presences on magneto‐hydrodynamic flow and heat transfer of a viscous fluid induced by a magnetized permeable heated stretching surface are studied in this article. The Lorentz force and Joule heating are also taken into consideration. The Oldroyd‐B model of polymers is used to study polymer presence which adds an extra stress in the mathematical model due to the polymer stretching. An iterative numerical scheme is opted to solve the set of ruling equations of the problem. Polymers stretch in the boundary layer region due to high velocity gradients. Polymer stretching reduces the zero‐shear viscosity near the surface but the polymeric viscosity (the total contribution of viscosity due to polymer addition) still remains positive, which cause velocity to reduce in the boundary layer region. Polymers are found to have no impact on the bulk. Skin friction along with heat and magnetic fluxes at the surface are evaluated with increasing polymer concentration. Zero polymer concentration represents the absence of polymers. Reduction in heat and magnetic fluxes and drag at the surface is observed in consequence of polymer addition. Polymer effects on skin friction, heat flux, and magnetic flux with respect to different values of magnetic force parameter, magnetic Prandtl number, magnetic interaction parameter, and the Eckert number are also thoroughly analyzed and graphically presented.

Intracellular Oxidative Stress Induced by Physical Exercise in Adults: Systematic Review and Meta-Analysis.

A physical exercise program is one of the commonly used methods for improving an individual’s antioxidative capacity. However, an inappropriate physical exercise program would induce extra oxidative stress (OS), and the relationship between the details of a physical exercise protocol and the severity of intracellular OS is still unclear. A systematic review and meta-analysis of randomized controlled trials were conducted by searching PubMed, Medline, and Web of Science with the eligibility criteria: (1) participants over 18 years old; (2) physical exercise interventions; (3) 8-hydroxydeoxyguanosine, F2-isoprostanes, and protein carbonyls (PCs) as outcome measures; (4) published in English and peer-reviewed. 12 studies were included, and the data of 8 in them were pooled together. The agreement between authors reached a kappa value of 0.73. The results of the meta-analysis showed that: (1) the level of OS did not depend on the absolute intensity of physical exercise but on both the intensity and the volume of exercise; (2) high-intensity aerobic exercise (HIAE) and a combined protocol of HIAE and resistance training had the highest potential to induce large OS in unhealthy people; (3) the OS induced by moderate-to-high intensity aerobic exercise was significantly larger than that induced by ordinary life activities in healthy adults; (4) high-intensity interval training and moderate-intensity aerobic exercise had the lowest and sub-lowest probabilities to induce high intracellular OS for unhealthy adults. activities induce OS in various tissues in the human body, and the severity of OS depends on many factors of physical exercises as well as the health condition of an individual. A high-intensity and high-volume physical exercise program has the largest possibility of inducing severe OS, while a moderate-intensity aerobic exercise program and a high-intensity interval training program with a relatively low volume might be beneficial to the redox balance for unhealthy individuals. In conclusion, continuous aerobic exercise under moderate-intensity or high-intensity interval training could be recommended to enhance the body’s capacity for maintaining redox balance, especially for unhealthy individuals. The PROSPERO Registration Number is CRD42022349687.

Towards strength-ductility enhancement of titanium matrix composites through heterogeneous grain structured Ti matrix design

To achieve a good combination of strength and ductility of titanium matrix composites, a kind of TiB/Ti-TiB/TA15 laminated composite was designed, and a heterogeneous grain structure was introduced in the matrix. The TiB/Ti-TiB/TA15 composite was fabricated by reaction hot pressing and hot rolling. Through subsequent short-term (10 min) annealing at 800 °C, a heterogeneous grain structure consisting of equiaxed α in the Ti matrix, elongated α and nano-recrystallized α in the TA15 matrix was formed. The composite herein showed significant improvement in ductility. The tensile elongation reached nearly 20%, which was almost three times that of the as-sintered one. The tensile strength was also enhanced by over 160 MPa compared with the as-sintered composite. The strength-ductility synergy was improved. The result of slip trace analysis exhibited that nearly 30% α grains stimulated the pyramidal slip system, which can coordinate deformation at the layer interface and relieve stress concentration caused by TiB whiskers. The heterogeneous grain structure contributed to the extra back stress strengthening effect, which enhanced the strain hardening ability of the composite. It was estimated that the heterogeneous structured titanium matrix provided extra back stress of approximately 250 MPa.

Use of a Geometric Parameter for Characterizing Rigid Films at Oil-Water Interfaces.

Interfacial tension and dilatational rheology are often used to characterize the mechanical response of a liquid interface using axisymmetric drop shape analysis (ADSA). It is important to note that for systems dominated by adsorption/desorption of surfactants, the contributions of extra mechanical stresses are negligible; thus, the Young-Laplace equation remains valid. However, for interfaces dominated by extra stresses, as in the case of particle monolayers or asphaltenes that clearly exhibit a skin (a rigid film), the nature of the elastic response is fundamentally different and the validity of the equation is questionable. Calculation of the interfacial tension and dilatational elasticity using drop shape analysis depends critically on the drop shape following the Young-Laplace equation. If the interface becomes more like a solid, the drop shape will deviate from being purely Laplacian. Indeed, the drop will exhibit a wrinkled surface as collapse continues. The geometric parameter RV/A, defined as the ratio (dV/V)/(dA/A) with V is the volume of the drop and A is the area of the interface), allows one to measure the deviation of the drop shape from purely Laplacian. For a simple interface (pure liquids or surfactant solutions), RV/A is quite close to the theoretical value of 1.5 of a perfect sphere. Nevertheless, if the molecules adsorbed at the interface begin to interact strongly, the ratio can vary. In the limit of long-time-scale experiments, RV/A of some drops approaches 2. We studied the evolution of the parameter RV/A for different systems, from simple to complex, as a function of oscillation frequencies and amplitudes of drop volume. The results obtained were compared to the values of the interfacial moduli and drop shape behavior to better characterize the regime change.

Energy saving and environment protection solution for the submarine pipelines based on deep learning technology

Underwater flowlines (pipelines and cables) have become a popular option worldwide as communication lines. Correspondingly the demand for underwater trenching increased with the most desirable method internationally, jet trenching for its benefits in protecting the flowlines from external hazards. However, the trenching method is suffering from a main problem that can affect the construction and operation phases. This problem is the use of maximum jetting pressure needed for underwater trenching which leads to extra costs in the construction phase. Furthermore, the unstraightening of the trench can cause extra stress on the flowline requiring extra maintenance in the operation phase. The key cause of this problem is the classification of the underwater soil, as if the underwater soils cannot be classified as accurately as possible, the suitable jetting pressure required to trench these soils could not be applied correctly. Therefore, this research aims to develop a machine learning classifier for soil classification as a solution for enhancing the performance of the underwater trenching process. This classifier was constructed, trained, and evaluated by MATLAB R2020a to classify the underwater soil type by analyzing the soil image samples by an artificial neural network (ANN). Then a prototype that mimics exactly the real trenching mechanism was built to test the developed classifier based on three different types of soil (sand, clay & gravel). The results showed that the classifier successfully identify and classify the three different types of soil used. Finally, the results confirmed that the classifier will enhance the trenching processes. As it eliminates the need for soil classification by conventional methods while executing it in an easy fast process that will save energy, and cost, and decrease the need for future maintenance processes.

Fractionalization of MENA Countries in Political Economy Categories

The article dwells on configuring Middle East and North Africa (MENA) countries in three political economy dimensions: population, gross national income per capita in current international dollars converted by purchasing power parities (per capita GNI PPP), and human development measured by the Human Development Index (HDI). Furthermore, the relationship between the mentioned dimensions and self-reported life satisfaction as well as the Index of Happiness is analyzed. The author conducts comparative analysis of diversity within a target region, shows where it fits on the world scale, and focuses on drawbacks in the data. The author concludes that the MENA region is a volitile cluster from the standpoint of safety, political rationality, and living standards. Armed clashes, technogenic accidents, the refugee problem in coping with the trend of demographic growth will put extra stress on the national economies of states and create great challenges for the governments.

Effect of perceived risk, challenges, and coping on anxiety and depression among frontline health workers during the COVID-19 pandemic in Bangladesh

Background: During the COVID-19 pandemic the health care workers (HCWs) encountered one of the heaviest blows by saving lives while endangering their own. This study was carried out to investigate risk exposures, risk perceptions, challenges, and coping strategies, leading to anxiety and depression, among HCWs in Bangladesh. Methods: This hospital-based cross-sectional survey was conducted from February to July 2021 among 1,112 frontline HCWs. Data were collected using a pre-tested self-administered questionnaire including Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder (GAD-7) scale. A coping scale for COVID-19 (CS-COV-19) was developed and validated. To determine the predictors for symptoms of depression and anxiety, multivariable logistic regression analysis was performed, and the associations between key variables are presented as odds ratios (ORs) and 95% CIs. Results: A total of 54.9% (n=389) doctors and 51.4% (n= 207) nurses were found to have mild to severe anxiety status and 47% (n=333) doctors and 39.9% (n= 159) nurses were found to have mild to severe depression. HCWs, family members, neighbors had been affected with COVID-19 and those who experienced extra stresses at work were two times more likely to have anxiety. HCWs who had worried family and friends that they might get infected through them, confronted any negative social attitude or perceptions, decreased monthly income, and depression were 1.57 to 1.8 times more likely to experience anxiety than those who did not go through these experiences. Health workers who confronted negative social attitudes or social perceptions were 1.7 times more likely to have depression. Respondents, who had family members infected with COVID-19 and HCWs who worked for long hours at hospitals were almost two times more likely to have depression. Conclusions: The findings will help promoting advocacy and encourage implementing selective interventions to protect the mental health and wellbeing of HCWs working with COVID-19.

Hydrodynamic instabilities of activity-balanced binary suspensions

We have built a mean-field kinetic model to study the underlying hydrodynamic instabilities in dilute, activity-balanced pusher-puller binary suspensions that produce near-zero mean extra stress. We have successfully demonstrated that mixing pushers and pullers in such binary systems may lead to much richer behaviors than a simple neutralization process due to the cancellation of stresslets from both species. Also, we find the instability mechanisms to be different from those derived for pure pushers or pullers, where a net extensile extra stress typically indicates unstable dynamics.

Burnout syndrome among healthcare workers during COVID-19 Pandemic in Accra, Ghana.

The emergence of the corona virus disease 2019 (COVID-19) has increased the workload of health workers particularly those in sub-Saharan Africa predisposing them to extra job-related stress and its associated job-related burnout. Burnout reduces the number, distribution and productivity of health workers. This study sought to determine personal and job-related characteristics of health workers in Accra, Ghana that influenced their experience of burnout during the COVID-19 pandemic. A cross-sectional study was conducted among 1,264 health workers recruited from three public hospitals in Accra, Ghana between March to November, 2020. The participants were recruited using a proportionate stratified sampling technique and completed a pre-tested questionnaire that collected information on socio-demographic and job-related factors. Also, the questionnaire assessed participants' level of resilience and job-related burnout. Pearson's chi-square test was used to determine the association between burnout and the socio-demographic as well as job-related factors. However, for variables with observations less than six, a Fisher's exact test, was used to determine the associations. After the binary analysis, multivariate logistic regressions were used to determine the strength of association between the socio-demographic as well as job-related factors and burnout. Data analyses were conducted at a significant level (alpha 0.05) and power of 95% confidence with the aid of Stata 15.0. The prevalence of burnout among the participants was 20.57% with non-clinicians displaying higher burnout compared to clinicians (26.74&% v 15.64%, p< 0.001). Health workers with 1-5 years working experience were 26.81 more likely to experience burnout (AOR = 26.81, CI = 6.37-112.9). Night shifts defined as shifts between 8:00pm to 8:00am was associated with the 1.86 odds of experiencing burnout (OR = 1.86; 95% CI: 1.33-2.61; p<0.001). Also, participants of the primary level facility were 3.91 times more likely (AOR = 3.91, 95% CI = 2.39-6.41) to experience burnout on the job. Similarly, participants with additional jobs were 1.14 times more likely (AOR = 1.14, 95% CI = 0.75-1.74) to experience burnout. In addition, participants harboring intentions of leaving their current jobs were 4.61 times more likely (AOR = 4.61, 95% CI = 2.73-7.78) to experience burnout. Furthermore, participants with perceived high workload were 2.38 times more likely (AOR = 2.38, 95% CI = 1.40-4.05) to experience burnt-out on the job. There is high prevalence of burnout among health workers in Accra particularly during the onslaught of the COVID-19 pandemic. Working on night shifts and at the primary level of healthcare is significantly associated with increased odds of experiencing burnout.We recommend shift rotation for staff and adequate resource provision for primary level hospitals. The high burnout in this study could be influenced by other factors such as the grief caused by multiple losses and also the limited supportive resources for health workers.