Relationship between Stress Perceived and Gastrointestinal Symptoms in Intensive Care Nurses During COVID-19 Pandemic: A Cross-Sectional Study

The purpose of this study is to determine the relationship between perceived stress and gastrointestinal (GI) symptoms during the COVID-19 outbreak in the intensive care unit (ICU) nurses. This cross-sectional study was conducted with 170 nurses working in the ICUs of a hospital in eastern Turkey. Descriptive, chi-square and multiple linear regression analyses were used to analyze data. In the last three months, 48.2% of the nurses had complaints such as heartburn, 44.1% abdominal distension, 41.7% diarrhea/ constipation. The mean perceived stress level experienced by the nurses was found to be 29.30±5.73. Results from regression analysis included perceived stress score, gender, perceived health status, diet, having been infected with COVID-19 before and risk degree of the ICU in question in terms of COVID-19 revealed a statistically significant associated with scores obtained from GI symptoms. Perceived stress level, health perception status, having been infected with COVID-19 before and the high-risk status of the intensive care unit in question for COVID-19 were predictive factors for the occurrence of gastrointestinal symptoms. These findings may provide a basis for creating a healthy work environment where factors contributing to work-related stress are reduced and coping strategies are developed. Keywords: gastrointestinal symptoms, intensive care, nurses, stress

Caffeic Acid Prevents Vascular Oxidative Stress and Atherosclerosis against Atherosclerogenic Diet in Rats

Diet and lifestyle play a crucial role in the progress of some cardiovascular disorders (CVDs). Rising interest in natural products and their pharmacological investigations witnessed therapeutic potential against CVDs. Caffeic acid (CA) is an organic composite hydroxycinnamic acid derivative classified among phenolics. It is a secondary metabolite biosynthesized in all plant species in the form of ester conjugates. The reported pharmacological activities of CA are neuroprotective, cardioprotective, hypoglycemic, antioxidant, and immunomodulatory properties. This work is aimed to examine the outcome of CA in atherogenic diet- (Ath-) induced rat model on lipid profile changes and endothelium function. The method involves a study duration of 35 days utilizing (n = 6) male Wistar rats (180–200 g) that were fed either normal chow or Ath. Study groups are given (i) normal chow diet, (ii) Ath, (iii) Ath + CA (25 or 50 mg/kg, p.o.), (iv) normal chow diet + CA (50 mg/kg, p.o.), and (v) Ath + Atorvastatin (ATORVA) (5 mg/kg, p.o.). Blood samples were collected at the end of the study to measure serum lipid profile, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and tissue oxidative stress level. Hemodynamic parameters and aorta staining were performed. CA treatment ameliorated lipid profile and significantly reduced the oxidative stress level. Aorta staining examination revealed a marked reduction of the atherosclerotic lesions. These findings suggested that CA is an effective treatment approach for preventing atherosclerotic lesion progression attributed to protection against oxidative stress and various enzymatic activities in the Ath model.

Simultaneous Classification of Both Mental Workload and Stress Level Suitable for an Online Passive Brain–Computer Interface

Research studies on EEG-based mental workload detection for a passive BCI generally focus on classifying cognitive states associated with the performance of tasks at different levels of difficulty, with no other aspects of the user’s mental state considered. However, in real-life situations, different aspects of the user’s state such as their cognitive (e.g., level of mental workload) and affective (e.g., level of stress/anxiety) states will often change simultaneously, and performance of a BCI system designed considering just one state may be unreliable. Moreover, multiple mental states may be relevant to the purposes of the BCI—for example both mental workload and stress level might be related to an aircraft pilot’s risk of error—and the simultaneous prediction of states may be critical in maximizing the practical effectiveness of real-life online BCI systems. In this study we investigated the feasibility of performing simultaneous classification of mental workload and stress level in an online passive BCI. We investigated both subject-specific and cross-subject classification approaches, the latter with and without the application of a transfer learning technique to align the distributions of data from the training and test subjects. Using cross-subject classification with transfer learning in a simulated online analysis, we obtained accuracies of 77.5 ± 6.9% and 84.1 ± 5.9%, across 18 participants for mental workload and stress level detection, respectively.

Extracorporeal Cardiac Shock Wave-Induced Exosome Derived From Endothelial Colony-Forming Cells Carrying miR-140-3p Alleviate Cardiomyocyte Hypoxia/Reoxygenation Injury via the PTEN/PI3K/AKT Pathway

Background: Stem cell-derived exosomes have great potential in the treatment of myocardial ischemia–reperfusion injury (IRI). Extracorporeal cardiac shock waves (ECSW) as effective therapy, in part, could activate the function of exosomes. In this study, we explored the effect of ECSW-induced exosome derived from endothelial colony-forming cells on cardiomyocyte hypoxia/reoxygenation (H/R) injury and its underlying mechanisms.Methods: The exosomes were extracted and purified from the supernatant of endothelial colony-forming cells (ECFCs-exo). ECFCs-exo treated with shock wave (SW-exo) or without shock wave (CON-exo) were performed with high-throughput sequencing of the miRNA. H9c2 cells were incubated with SW-exo or CON-exo after H/R injury. The cell viability, cell apoptosis, oxidative stress level, and inflammatory factor were assessed. qRT-PCR was used to detect the expression levels of miRNA and mRNA in cells and exosomes. The PTEN/PI3K/AKT pathway-related proteins were detected by Western blotting, respectively.Results: Exosomes secreted by ECFCs could be taken up by H9c2 cells. Administration of SW-exo to H9c2 cells after H/R injury could significantly improve cell viability, inhibit cell apoptosis, and downregulate oxidative stress level (p < 0.01), with an increase in Bcl-2 protein and a decrease in Bax, cleaved caspase-3, and NF-κB protein (p < 0.05). Notably, miR-140-3p was found to be highly enriched both in ECFCs and ECFCs-exo treated with ECSW (p < 0.05) and served as a critical mediator. SW-exo increased miR-140-3p expression but decreased PTEN expression in H9c2 cells with enhanced phosphorylation of the PI3K/AKT signaling pathway. These cardioprotective effects of SW-exo on H/R injury were blunted by the miR-140-3p inhibitor. Dual-luciferase assay verified that miR-140-3p could directly target the 3′UTR of PTEN mRNA and exert a negative regulatory effect.Conclusion: This study has shown the potential of ECSW as an effective stimulation for the exosomes derived from ECFCs in vitro. SW-exo exerted a stronger therapeutic effect on H/R injury in H9c2 cells possibly via delivering exosomal miR-140-3p, which might be a novel promising strategy for the myocardial IRI.

COVID-19-related school disruptions and well-being of children and adolescents in Geneva

Background Various studies showed the negative impact of COVID-19-related lockdowns and school closures on the well-being of children and adolescents. However, the prevalence and consequences of occasional short-term school disruptions due to COVID-19-related quarantine or isolation remain unknown. This study evaluated their impact on the well-being and stress level of children and adolescents. Methods In June/July 2021, we conducted a survey selecting a representative sample of children and adolescents of a Swiss canton population. Parents of school-aged children reported information about them missing school because of COVID-19, from August 2020 to June 2021, as well as about their health-related quality of life (HRQoL) measured with the KINDL® scale and their stress level. Results Among the 538 participants, 216/538 (40.1%) pupils missed school at least once for COVID-19-related causes, with a total of 272 absences. We observed no relationship between the frequency of COVID-19-related absences and the HRQoL or stress level, even when stratifying by the type of absence or socio-demographic factors. Discussion Overall, these findings are reassuring in that quarantines and related school disruptions, which we know are a common and effective way of controlling SARS-CoV-2 transmission, did not seem to meaningfully impact children and adolescent's wellbeing and stress. Finding the right balance between SARS-CoV-2 control and young populations' well-being is challenging, and the current results provide additional information for decision makers.

Effect of operating parameters on functional fatigue characteristics of an Ni-Ti shape memory alloy on partial thermomechanical cycling

In this study, the influence of upper cycle temperature (maximum temperature in a cycle) and the magnitude of applied stress on the functional properties of an SMA during partial thermomechanical cycling has been studied. A near-equiatomic NiTi SMA was chosen and tested under different upper cycle temperatures (between martensite finish (Mf) and austenite finish (Af) temperatures) and stress level (below and above the yield strength of the martensite). The upper cycle temperature was varied by controlling the magnitude of the current supply. The results show that a raise in the upper cycle temperature causes the permanent strain to increase and also lowers the stability. However, decreasing the stress imposed to a value lower than the yield strength of the martensite improves cyclic stability. The upper cycle temperature was found to influence the crack nucleation, whereas the applied stress level the crack propagation during partial thermomechanical cycling of SMAs. Therefore, decreasing the upper cycle temperature as well as the magnitude of stress applied to lower than the yield stress of martensite have been found to be suitable strategies for increasing the lifespan of SMA-based actuators during partial thermomechanical cycling.

Fatigue Performance of Natural and Synthetic Rattan Strips Subjected to Cyclic Tensile Loading

Tensile fatigue performances of selected natural rattan strips (NRSs) and synthetic rattan strips (SRSs) were evaluated by subjecting them to zero-to-maximum constant amplitude cyclic tensile loading. Experimental results indicated that a fatigue life of 25,000 cycles began at the stress level of 50% of rattan material ultimate tensile strength (UTS) value for NRSs evaluated. Rattan core strips’ fatigue life of 100,000 cycles started at the stress level of 30% of its UTS value. Rattan bast strips could start a fatigue life of 100,000 cycles at a stress level below 30% of material UTS value. SRSs didn’t reach the fatigue life of 25,000 cycles until the applied stress level reduced to 40% of material UTS value and reached the fatigue life of 100,000 cycles at the stress level of 40% of material UTS value. It was found that NRSs’ S-N curves (applied nominal stress versus log number of cycles to failure) could be approximated by S=σou(1−H×log10⋅Nf). The constant H values in the equation were 0.10 and 0.08 for bast and core materials, respectively.

Experimental Study on Freeze-Thaw Effects on Creep Characteristics of Rubber Concrete

Crumb Rubber Concrete (CRC) can exhibit high freeze-thaw resistance, but its long-term creep behavior under various freeze-thaw conditions remains unclear, which is essential for the safety of pavement engineering in the severe cold zone. In this study, the freeze-thaw effects on the creep behavior of CRC under different stress levels were systematically analyzed by testing the compressive strength, the uniaxial creep under different stress levels, and the dynamic elastic modulus. To simulate real conditions of the road environment in the cold area, the lowest temperature of −20°C, six freeze-thaw cycles of 0, 30, 60, 90, 120, and 150, and seven different stress levels of 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9 of the compressive strength were employed in this study. The test results showed that the mass loss rate was 6%–11.2% and the compressive strength decreased by 6.51%–47% after 30–150 freeze-thaw cycles. When the stress level reached its critical value, the relative dynamic elastic modulus decreased with the number of freeze-thaw cycles. After 150 freeze-thaw cycles, failure did not appear when the stress level was lower than 50%, above which the creep failure was determined by the stress level and the number of the freeze-thaw cycles. Meanwhile, it was found that the cracking and interfacial debonding between the matrix and the crumb rubber particle were the main reasons for the degradation of CRC creep performance. Finally, a Weibull distribution-based empirical creep damage model was established to predict the failure of CRC, which can enhance its application to related engineering.