The aim of this study was to investigate the correlations between serum calcium and clinical outcomes in patients with coronavirus disease 2019 (COVID-19). In this retrospective study, serum calcium levels, hormone levels and clinical laboratory parameters on admission were recorded. The clinical outcome variables were also recorded. From February 10 to February 28, 2020, 241 patients were enrolled. Of these patients, 180 (74.7%) had hypocalcemia on admission. The median serum calcium levels were 2.12 (IQR, 2.04-2.20) mmol/L, median parathyroid hormone (PTH) levels were 55.27 (IQR, 42.73-73.15) pg/mL, and median 25-hydroxyvitamin D (VD) levels were 10.20 (IQR, 8.20-12.65) ng/mL. The serum calcium levels were significantly positively correlated with VD levels (P =0.004) but negatively correlated with PTH levels (P =0.048). Patients with lower serum calcium levels (especially ≤2.0 mmol/L) had worse clinical parameters, higher incidences of organ injury and septic shock, and higher 28-day mortality. The areas under the receiver operating characteristic curves of multiple organ dysfunction syndrome, septic shock, and 28-day mortality were 0.923 (P <0.001), 0.905 (P =0.001), and 0.929 (P <0.001), respectively. In conclusion, serum calcium was associated with the clinical severity and prognosis of patients with COVID-19. Hypocalcemia may be associated with imbalanced VD and PTH levels.

The aim of this study was to investigate the risk factors of hypoalbuminemia and effects of different albumin levels on the prognosis of surgical septic patients. We preformed a retrospective clinical study including 135 adult patients from September 2011 to June 2014. The albumin levels and severity markers were recorded during the first 48 h after enrollment, and logistic regression analyses were used to determine the risk factors. The outcomes of patients with different albumin levels were also compared. The acute physiology and chronic health evaluation II (APACHE II) score (OR 1.786, 95% CI [1.379–2.314], P < 0.001), C-reactive protein (CRP) (OR 1.016, 95% CI [1.005–1.027], P = 0.005), and blood lactate (OR 1.764, 95% CI [1.141–2.726], P = 0.011) were established as the independent risk factors of hypoalbuminemia in patients with surgical sepsis. The severity markers and outcomes of patients with albumin levels ≤20 g/L were significantly worse than that of 21–25 g/L and ≥26 g/L, whereas the latter two groups had similar prognosis. Every 1 g/L decrease of albumin level below the optimal cut-off (23 g/L) was associated with a 19.4% increase in hospital mortality and a 28.7% increase in the incidence of multiple organ dysfunction syndrome. In conclusion, APACHE II score (≥14.5), CRP (≥34.25 mg/L), and blood lactate (≥.35 mmol/L) were established as the independent risk factors of hypoalbuminemia in the early stage of surgical sepsis. Patients with baseline albumin level ≤20 g/L had worse prognosis than that of albumin level ≥21 g/L. Albumin levels were negatively correlated the prognosis of surgical sepsis when below about 23 g/L.

A series of Co3O4–MnCo2O4/N‐doped reduced graphene oxide (CMO/N‐rGO) electrocatalysts with different N‐rGO content were developed by using a two‐step synthetic method. The electrocatalysts were characterized by X‐ray diffraction, scanning electron microscopy/transmission electron microscopy, and X‐ray photoelectron spectroscopy. Their catalytic activities toward the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) were evaluated by linear‐sweep voltammetry (LSV) in an alkaline electrolyte. It is found that GO is vital for the formation of CMO/N‐rGO nanocomposite during the preparation. The CMO hybrid nanoparticles can be obtained through feeding GO during the preparation, but only the single spinel oxide, i.e. MnCo2O4, is formed without adding GO, even if the feeding molar ratio of Co and Mn (Co/Mn) is higher than 2. The CMO/N‐rGO nanocomposite electrocatalysts can efficiently take advantages of ORR and OER active sites from the CMO hybrid oxides and N‐rGO, as well as the enhanced charge transfer from N‐rGO, thus bringing about higher bifunctional activities towards ORR/OER in alkaline electrolyte, as compared with Co3O4, MnCo2O4, and N‐rGO. The CMO/N‐rGO nanocomposites are considered to be promising bifunctional electrocatalysts for ORR/OER.