Background Currently, the SARS-CoV-2 promptly spread across China and around the world. However, there are controversies about whether preexisting chronic kidney disease (CKD) and acute kidney injury complication (AKI) are involved in the COVID-19 pandemic. Measurements Studies reported the kidney outcomes in different severity of COVID-19 were included in this study. Standardized mean differences or odds ratios were calculated by employing Review Manager meta-analysis software. Results Thirty-six trials were included in this systematic review with a total of 6395 COVID-19 patients. The overall effects indicated that preexisting CKD (OR = 3.28), complication of AKI (OR = 11.02), serum creatinine (SMD = 0.68), abnormal serum creatinine (OR = 4.86), blood urea nitrogen (SMD = 1.95), abnormal blood urea nitrogen (OR = 6.53), received continuous renal replacement therapy (CRRT) (OR = 23.63) were significantly increased in severe group than that in nonsevere group. Additionally, the complication of AKI (OR = 13.92) and blood urea nitrogen (SMD = 1.18) were remarkably elevated in the critical group than that in the severe group. Conclusions CKD and AKI are susceptible to occur in patients with severe COVID-19. CRRT is applied frequently in severe COVID-19 patients than that in nonsevere COVID-19 patients. The risk of AKI is higher in the critical group than that in the severe group.

An experimental investigation was undertaken into the seismic performance of a precast prestressed concrete frame system. A total of three beam-to-column connection models were designed, built, and tested to failure to evaluate their strength and ductility properties under cyclic loading. The comparative study showed that the hysteretic loops were full and the joints had better energy dissipation capacity. It was concluded that satisfactory seismic performance could be expected from this frame system if the slip of the U-shaped reinforcing steel bar was controlled well on the zone of joint. Then the finite element method (FEM) was used to analyze the specimen and the calculation results were in good agreement with those of the test.

A series of Pd/γ-Al2O3 catalysts with different additons of Pd were prepared by impregnation. The effect of calcination condition and Pd loading on catalytic performance of catalysts for one-step dimethyl ether synthesis has been investigated. The physic-chemical performance and structure of Pd/γ-Al2O3 catalysts were characterized by CO-TPD, TGA and nitrogen physisorption. The results show that the dispersion of Pd and the amount of adsorbration on the CO-bridge of Pd could be increased to by the moderate microwave heating on the catalysts, and the catalyst performance can be improved. But a large number of surface acidic sites of Pd/γ-Al2O3 are covered by highly fragmented Pd-grain, it causes DME selectivity reduced. And the excessive Pd can reduce the samples’ surface acid, decrease the dispersion of the metal Pd and block up the pore of γ-Al2O3. The CO conversion rate and DME space-time yield could reach 60.1% and 28.76 mmol·g-1·h-1 respectively at 2% Pd loading, at this time Pd/γ-Al2O3 has a high Pd activity surface and ideal acid sites.

A series of Pd-CeO2/γ-Al2O3 catalysts which have a different CeO2 loading were prepared by impregnation under microwave irradiation. Based on various characterizations, such as XRD, H2-TPR and CO-TPD, the effect of CeO2 loading on catalytic performance and stability of Pd/γ-Al2O3 were examined for one-step dimethyl ether synthesis from syngas. The results show that there are two completely opposite effect on the CO conversation rate of Pd/γ-Al2O3 catalysts after adding CeO2, namely that it can improve Pd dispersion at a suitable loading, hence the CO conversation rate will increase too. However, the surface area and total pore volume of Pd/γ-Al2O3 catalysts decrease by adding excessive CeO2 and CO conversation rate will also reduce. When the CeO2 loading achieve to 2%, catalysts can have relatively high catalytic stability and activity that the CO conversation rate and DME space-time yield can reach 64.7% and 27.82 mmol·ml-1·h-1, respectively.

LiFe 1-x Mn x PO 4/ C composites were prepared as cathode material for lithium ion battery via solid-state reaction and using glucose as reducing agent and carbon source. The crystal structure and morphology were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The resultant samples were pure olivine compounds with an orthorhombic structure. Their electrochemical performance was studied by galvanostatic charge–discharge test and cyclic voltammetry. The results showed that the sample LiFe0.8Mn0.2PO4/C with an average particle size of 400 nm exhibited the largest discharge capacity of 150 mAh g-1, excellent reversibility of charge–discharge and high capacity retention of 97% after a 50-cycle CV scanning. The improved electrical conductivity corresponding to the fine carbon layer around the LiFe0.8Mn0.2PO4 individual particle can be responsible for all these excellent electrochemical performance.