A highly crystalline porous copper‐based metal–organic framework MOF‐199 was synthesized from the reaction of 1,3,5‐benzenetricarboxylic acid and copper nitrate trihydrate by a solvothermal method. The MOF‐199 was characterized by several techniques, including X‐ray powder Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA), Fourier Transform‐Infrared (FT‐IR), Atomic Absorption Spectrophotometry (AAS), and nitrogen physisorption measurements. The MOF‐199 proved to be an efficient catalyst for the C‐arylation of aryl iodides with acetylacetone to form α‐aryl ketones as the principal products. The catalyst can be separated from the reaction mixture by simple decantation, and be reused without significant degradation in catalytic activity. No contribution from homogeneous catalysis of active species leaching into the liquid phase was detected, confirming that the MOF‐199 is a truly heterogeneous catalyst.

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ObjectiveWe assessed the psychological impact posed by COVID-19 and its associated factors on the healthcare workforce nationwide during the peak of Vietnam’s fourth outbreak.DesignA cross-sectional study.SettingOur study was conducted in 61 provinces of Vietnam.MethodsA total of 2814 healthcare professionals in 61/63 provinces of Vietnam. An online questionnaire using Patient Health Questionnaire-9 (PHQ-9), Perceived Stress Scale-4 (PSS-4) and Generalised Anxiety Disorder-7 (GAD-7) scales was distributed randomly to a subgroup of 503 respondents.Primary and secondary outcome measuresTo determine the impact of COVID-19 on the psychological of health workers, we conducted analyses to test a primary hypothesis related to participants based on three main scales including PHQ-9, PSS-4 and GAD-7 scales.ResultsNearly half (49.7%) of healthcare workers experienced mild depression symptoms, 34.0% underwent moderate anxiety symptoms and 49.3% reported high-stress levels. Respondents who had a monthly income below 5 million VND (~US$212) and had more than 3 days of duty per week had a higher score on the anxiety scales. Compared with medical doctors, nurses/midwives had lower PHQ-9 (Coef=−2.53; 95% CI=−3.71 to −1.36) and GAD-7 scores (Coef=−2.36; 95% CI=−3.56 L to −1.16). Increased workload and work time was the harmful factor that increase the PHQ-9, GAD-7 or PSS-4 scores. More than half (53.9%) of respondents stated no demand for mental healthcare services.ConclusionsHealth workers who gained less financial rewards are reported to have higher levels of mental distress than others, implying the need for a raise in basic salary as well as compensation and encouragement schemes. To tackle hesitancy in seeking mental help, integrating online mental health therapy with e-health consultations via social media can be strategically implemented to augment service delivery, and simultaneously enhance the standard of mental health services.

This paper presents the control model of three phase grid- connected photovoltaic inverter based on the analysis of operating principle of two-stage conventional gridconnected inverter. The mathematical model of inverter under dq frame is set up and the overall control strategy of two-stage photovoltaic grid-connected inverter is proposed in this paper. To overcome the distortion general caused by switching effect on sensors, a Kalman filter is introduced. The control strategy was simulated on Matlab – Simulink to verify the steady and dynamic of model, improving the quality of electrical power to consumers.