A Study on the Critical Saturation Response Characteristics of Simple and Sandwich Cylindrical Shells under Long-Duration Blast Loading.

Experimental research and numerical simulations of the structural response to shock waves with pulse durations of hundreds of milliseconds, or even seconds, are extremely challenging. This paper takes typical single-layer and sandwich cylindrical shells as the research objects. The response rules of cylindrical shells under long-duration blast loadings were studied. The results show that when the pulse duration is greater than or equal to 4~5 times the first-order period of the structure, the maximum response of the structure tends to be consistent, that is, the maximum response of the cylindrical shells with different vibration shapes shows a saturation effect as the pulse duration increases. This study established the relationship between the saturation loading time and the inherent characteristics of the structure. It was found that the saturation effect was applicable under the following conditions, including different load waveforms, elastic-plastic deformation of the structure, and the loading object being a sandwich shell. This will help transform the long-duration explosion wave problem into a finite pulse-duration shock wave problem that can be realized by both experiments and numerical simulations.

Perceived organizational support, self-efficacy and cognitive reappraisal on resilience in emergency nurses who sustained workplace violence: A mediation analysis.

AIMS: The aims of this study were as follows: (a) to examine the relationship between perceived organizational support and resilience; (b) to investigate the potential mediating role of general self-efficacy and cognitive reappraisal among emergency nurses who have experienced workplace violence; and (c) to explore the application of Kumpfer's resilience framework to emergency department nurses. DESIGN: A cross-sectional study. METHODS: From February 17, 2021, to March 8, 2021, 825 emergency nurses working in the emergency departments of tertiary hospitals in Shanghai, China, completed an online survey. Data on resilience, organizational support, cognitive reappraisal and general self-efficacy were collected through questionnaires. The Spearman analysis was employed to investigate the relationship between variables, while the mediation analysis was conducted using AMOS 23.0 statistical software. RESULTS: The findings of a study involving 825 emergency nurses who reported experiencing workplace violence reveal a positive correlation between perceived organizational support and resilience. Additionally, it has been observed that the relationship between these two factors is mediated by both cognitive reappraisal and general self-efficacy. Furthermore, the mediating effect of cognitive reappraisal is more significant in this relationship. CONCLUSION: Kumpfer's resilience framework is found to apply to emergency nurses. Perceived organizational support, an environmental factor, affects resilience directly and positively. In addition, cognitive reappraisal and general self-efficacy, which are individual factors, mediate this influence path. These findings suggest an interaction between environmental and individual factors in determining the resilience of emergency nurses. IMPACT: These findings have implications for developing resilience intervention strategies for emergency nurses exposed to occupational violence. Enhancing personal attributes such as general self-efficacy and cognitive reappraisal is as significant as strengthening external organizational support environments for enhancing nurses' resilience. PATIENT OR PUBLIC CONTRIBUTION: Emergency nurses participated in the pilot test of our questionnaire survey and gave their opinions on the questionnaire design. SUMMARY STATEMENT: What is already known about the topic? In emergency rooms, workplace violence is prevalent, and it seriously endangers nurses' physical and mental health. Enhancing resilience can improve nurses' ability to self-regulate after experiencing violence. However, the drivers and mechanisms of resilience among emergency nurses who have experienced workplace violence remain unidentified. What this paper adds? This study confirms the applicability of Kumpfer's resilience framework to emergency nurses who have experienced workplace violence. Nurses' self-efficacy and cognitive reappraisal mediate the relationship between perceived organizational support and resilience after exposure to workplace violence. The resilience process for emergency nurses involves the interaction of individual and environmental factors. Implications for practice/policy. Managers and researchers should consider the interaction between individual and environmental factors when developing resilience intervention strategies for emergency nurses who have suffered workplace violence. It is essential to support emergency nurses from the dyadic dimensions of the environment and the individual. A supportive organizational environment and individual positive adjustment strategies are equally important in promoting resilience among nurses.

Tetraphenylethylene sulfonate derivative as turn-on fluorescent sensor for berberine chloride detection in aqueous solution.

A negatively-charged tetraphenylethylene derivative (TPE-SE) was designed and synthesized as turn-on fluorescent sensor for berberine chloride (BBC) detection in aqueous solution. The fluorescent property and detection mechanism were elucidated by UV-vis absorption spectra, photoluminescence spectra, dynamic light scattering experiments. The results reveal that the BBC can lead to aggregation-induced emission of TPE-SE due to the electrostatic interactions, endowing TPE-SE with excellent turn-on detecting ability, high selectivity and sensitivity to BBC. The detection limit is as low as 6.58 × 10-6M. These results should be applicable to fabricate special turn-on fluorescent sensors towards various antibiotics, and it is crucially important for achieving reasonable control and intake of small biomolecules.

Decreased resting-state neural signal in the left angular gyrus as a potential neuroimaging biomarker of schizophrenia: An amplitude of low-frequency fluctuation and support vector machine analysis.

Objective: Schizophrenia (SCH) is primarily diagnosed based on specific clinical symptoms, with the lack of any objective SCH-related biomarkers often resulting in patient misdiagnosis and the underdiagnosis of this condition. This study was developed to assess the utility of amplitude of low-frequency fluctuation (ALFF) values analyzed via support vector machine (SVM) methods as a means of diagnosing SCH. Methods: In total, 131 SCH patients and 128 age- and gender-matched healthy control (HC) individuals underwent resting-state functional magnetic resonance imaging (rs-fMRI), with the resultant data then being analyzed using ALFF values and SVM methods. Results: Relative to HC individuals, patients with SCH exhibited ALFF reductions in the left angular gyrus (AG), fusiform gyrus, anterior cingulate cortex (ACC), right cerebellum, bilateral middle temporal gyrus (MTG), and precuneus (PCu) regions. No SCH patient brain regions exhibited significant increases in ALFF relative to HC individuals. SVM results indicated that reductions in ALFF values in the bilateral PCu can be used to effectively differentiate between SCH patients and HCs with respective accuracy, sensitivity, and specificity values of 73.36, 91.60, and 54.69%. Conclusion: These data indicate that SCH patients may exhibit characteristic reductions in regional brain activity, with decreased ALFF values of the bilateral PCu potentially offering value as a candidate biomarker capable of distinguishing between SCH patients and HCs.

The effects of early exercise on cardiac rehabilitation-related outcome in acute heart failure patients: A systematic review and meta-analysis.

BACKGROUND: Heart failure can be classified into chronic heart failure and acute heart failure. Rapid onsets or worsening symptoms characterize acute heart failure, while progressive symptoms characterize chronic heart failure. Exercise-based cardiac rehabilitation is recommended for chronic heart failure patients, yet controversies on whether early exercise is safe and advantageous for acute heart failure patients remain unclear. OBJECTIVES: We performed a systematic review and meta-analysis to explore the effects of early exercise on cardiac rehabilitation-related outcome in acute heart failure patients. METHODS: We searched PubMed, Web Of Science, Embase, the Cochrane Library, CINAHL, PsycINFO, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP), Wanfang Dataset and SinoMed Dataset (from the earliest date available to August 2021) for randomized controlled trials that evaluated the effects of early exercise in acute heart failure patients. Studies were selected according to inclusion and exclusion criteria. Data synthesis was performed with Review Manager 5.2. RESULTS: 13 studies met the study criteria, including 1466 patients. Compared to the control group [routine care], early exercise improved 6 min walk distance[mean difference = 33.10, 95% CI (31.43, 34.77), P < 0.001], short physical performance battery scores[mean difference = 1.40, 95% CI (1.36, 1.44), P < 0.001], N-terminal pro-B-type natriuretic peptide[mean difference = -58.84, 95% CI (-89.25, -28.43), P < 0.001], quality of life assessed by Minnesota heart failure quality of life questionnaire [mean difference = -6.55, 95% CI (-9.99, -3.11), P = 0.0002], quality of life assessed by Kansas city cardiomyopathy questionnaire [mean difference = 7.00, 95% CI (6.58, 7.42), P < 0.001], activities of daily living [mean difference = 4.43, 95% CI (2.20, 6.65), P < 0.001], and all-cause related readmission rate [mean difference = 0.69, 95% CI (0.51, 0.94), P = 0.02]. No significant difference in left ventricular ejection fraction [mean difference = 1.93, 95% CI (-2.19, 6.05), P = 0.36], heart failure-related readmission rate [mean difference = 0.76, 95% CI (0.50, 1.17), P = 0.21] and all-cause mortality [mean difference = 0.63, 95% CI (0.18, 2.24), P = 0.47] was found between early exercise group and control group. No adverse events occurred during the intervention. CONCLUSION: Compared to routine care, early exercise could significantly improve the effect of physical capacity, physiological outcomes and clinical outcomes in acute heart failure patients, and appeared to be safe.

Mental Symptoms and Stress of Hospitalized Schizophrenia Patients With 2019 Novel Coronavirus Disease: An Observation Study.

Background: The 2019 novel coronavirus disease (COVID-19) is an extremely rapidly spreading respiratory infection caused by SARS-CoV-2. Many schizophrenic patients were infected with COVID-19 in Wuhan City, Hubei Province. This study took hospitalized schizophrenia patients with COVID-19 as the research subjects and observed the changes in psychopathology and stress of patients with COVID-19 and the accompanying social isolation. Methods: To sort and isolate potential COVID-19-infected patients, an isolated ward was set up from January 30, 2020, to March 30, 2020. Schizophrenia patients with COVID-19 were referred to this ward, and long-term hospitalized cases were included in this study. The Positive and Negative Syndrome Scale and Perceived Stress Scale were used to evaluate the severity of mental symptoms and psychological stress in the early stage of the outbreak of COVID-19, after the diagnosis of COVID-19 and after recovery. At the time of diagnosis, we also extracted the patient's routine blood, biochemical and other indicators and asked the patient's perception of COVID-19. Results: 21 hospitalized schizophrenia patients with COVID-19 were recruited in this study. The changes in PANSS scores were not significant (p = 0.225 baseline vs. diagnosed, p = 0.399 cured vs. diagnosed). The CPSS scores increased significantly after diagnosis and transfer to the isolation ward (p < 0.001 baseline vs. diagnosed, p < 0.001 cured vs. diagnosed). The course of schizophrenia was a protective factor of stress levels to cases (t = -3.25, p = 0.006), and patients' perception of COVID-19 was a risk factor (t = 2.48, p = 0.038). The final multiple linear regression model was statistically significant (F = 8.16, p < 0.001). Conclusion: Hospitalized schizophrenia patients with COVID-19 had increased stress levels and negative symptoms but alleviated positive symptoms after medical isolated treatment. This reminds us that in the face of major epidemics, we must specifically alleviate the psychological burden at the peak of the epidemic and improve the prognosis of patients after the epidemic.

Strain Rate Sensitivity of Tensile Properties in Ti-6.6Al-3.3Mo-1.8Zr-0.29Si Alloy: Experiments and Constitutive Modeling.

The complex deformation usually involves wide strain-rate change. However, few efforts have been devoted to investigate the effect of strain rate history on the tensile behavior of α + ß titanium alloy. In present paper, tensile tests of Ti-6.6Al-3.3Mo-1.8Zr-0.29Si alloy were carried out under both constant and variable strain-rate conditions within the region from 10-3~500 s-1. A single stress pulse experimental technique was utilized to conduct the recovery tests. The strain-rate history effect was examined. It is found that the flow stress is independent on the strain rate history, though the alloy exhibits obvious positive strain rate sensitivity. The Taylor-Quinney coefficient of the plastic work converted to heat is proved as 0.9 at high strain rates. The cavitation fracture mechanism is revealed by microstructural observation over the full range explored. In basis of the experimental results and other pulished literatures, empirical Khan-Huang-Liang constitutive model was suitably modified to account for the strain-rate dependent behavior. Good agreement is achieved between the modeling prediction results and experimental data.