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Background The worldwide spread of SARS-CoV-2 has infected millions of people leading to over 0.3 million mortalities. The disruption of sodium homeostasis, tends to be a common occurrence in patients with COVID-19. Methods and results A total of 1,254 COVID-19 patients comprising 124 (9.9%) hyponatremic patients (under 135 mmol/L) and 30 (2.4%) hypernatremic patients (over 145 mmol/L) from three hospitals in Hubei, China, were enrolled in the study. The relationships between sodium balance disorders in COVID-19 patients, its clinical features, implications, and the underlying causes were presented. Hyponatremia patients were observed to be elderly, had more comorbidities, with severe pneumonic chest radiographic findings. They were also more likely to have a fever, nausea, higher leukocyte and neutrophils count, and a high sensitivity C-reactive protein (HS-CRP). Compared to normonatremia patients, renal insufficiency was common in both hyponatremia and hypernatremia patients. In addition, hyponatremia patients required extensive treatment with oxygen, antibiotics, and corticosteroids. The only significant differences between the hypernatremia and normonatremia patients were laboratory findings and clinical complications, and patients with hypernatremia were more likely to use traditional Chinese medicine for treatment compared to normonatremia patients. This study indicates that severity of the disease, the length of stay in the hospital of surviving patients, and mortality were higher among COVID-19 patients with sodium balance disorders. Conclusion Sodium balance disorder, particularly hyponatremia, is a common condition among hospitalized patients with COVID-19 in Hubei, China, and it is associated with a higher risk of severe illness and increased in-hospital mortality.

We have investigated the temperature dependence of photoluminescence ͑PL͒ properties of a number of self-organized InAs/GaAs heterostructures with InAs layer thickness ranging from 0.5 to 3 ML. The temperature dependence of InAs exciton emission and linewidth was found to display a significant difference when the InAs layer thickness is smaller or larger than the critical thickness around 1.7 ML. The fast redshift of PL energy and an anomalous decrease of linewidth with increasing temperature were observed and attributed to the efficient relaxation process of carriers in multilayer samples, resulting from the spread and penetration of the carrier wave functions in coupled InAs quantum dots. The measured thermal activation energies of different samples demonstrated that the InAs wetting layer may act as a barrier for the thermionic emission of carriers in high-quality InAs multilayers, while in InAs monolayers and submonolayers the carriers are required to overcome the GaAs barrier to escape thermally from the localized states. ͓S0163-1829͑96͒06440-5͔Spontaneous formation of three-dimensional ͑3D͒ islands during Stranski-Krastanov-like growth of highly strained InAs layers on GaAs substrates by molecular-beam epitaxy ͑MBE͒ has been proposed as a promising way for fabricating high-quality InAs quantum dots ͑QD's͒ in GaAs.1-6 When the thickness of an InAs layer is beyond a critical thickness of around 1.7 ML, the structure is usually composed of an InAs wetting layer and conelike InAs islands deposited on it. The density, size distribution, uniformity, and coverage of such InAs islands were found to be growth condition dependent, and have been investigated by TEM and atomic force microscopy ͑AFM͒ in recent years. [7][8][9] The optical studies 10-13 revealed its excellent radiative recombination, which usually gives a broadband with a reported full width at half maximum ͑FWHM͒ in the range of 50-130 meV. Recent work by Lubyshev et al. 13 presented the unusual temperature dependence of exciton energy in InAs multilayer structures. An anomalous decrease of the FWHM was detected and explained in terms of the tunneling process between InAs dots.In this paper, we studied the exciton relaxation and thermal activation in InAs multilayer structures via the analysis of cw photoluminescence ͑PL͒ data under different temperatures. It is found that the temperature dependence of the exciton energy and linewidth is significantly different from that obtained in InAs monolayers and submonolayers. The unusual temperature behavior in InAs multilayers is associated with the relaxation effect of carriers, resulting from the spread and penetration of the wave functions of carriers in coupled InAs QDs. In the study of the thermal activation process, we found that potential barriers for InAs excitons to escape thermally from the localized states are different for different structures. For high-quality InAs multilayers, the barrier could be the wetting layer, while in the case of monolayers or submonolayers the carriers are required to ove...

Early identification of severe patients with coronavirus disease 2019 (COVID-19) is very important for individual treatment. We included 203 patients with COVID-19 by propensity score matching in this retrospective, case-control study. The effects of serum lactate dehydrogenase (LDH) at admission on patients with COVID-19 were evaluated. We found that serum LDH levels had a 58.7% sensitivity and 82.0% specificity, based on a best cut-off of 277.00 U/L, for predicting severe COVID-19. And a cut-off of 359.50 U/L of the serum LDH levels resulted in a 93.8% sensitivity, 88.2% specificity for predicting death of COVID-19. Additionally, logistic regression analysis and Cox proportional hazards model respectively indicated that elevated LDH level was an independent risk factor for the severity (HR: 2.73, 95% CI: 1.25-5.97; P=0.012) and mortality (HR: 40.50, 95% CI: 3.65-449.28; P=0.003) of COVID-19. Therefore, elevated LDH level at admission is an independent risk factor for the severity and mortality of COVID-19. LDH can assist in the early evaluating of COVID-19. Clinicians should pay attention to the serum LDH level at admission for patients with COVID-19.