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Background: The spread of an novel coronavirus (SARS-CoV-2, previously named 2019-nCoV) has already taken on pandemic proportions, affecting over 100 countries in a matter of weeks. Elucidating the diagnostic value of different methods, especially the auxiliary diagnosis value of antibodies assays for SARS-CoV-2 infection is helpful for improving the sensitivities of pathogenic-diagnosis, providing timely treatment, and differentiating the infected cases from the healthy, thus preventing further epidemics. Methods: Medical records from 38 patients with confirmed SARS-CoV-2 infection in the Second Peoples Hospital of Fuyang from January 22, 2020 to February 28, 2020 were collected and retrospectively analyzed. Specimens including throat swabs, sputum and serum were collected during the hospitalization period, viral RNAs and serum IgM-IgG antibodies to SARS-CoV-2 were measured respectively. The detectability of different methods as well as the auxiliary diagnosis value of antibodies test for SARS-CoV-2 infection were analyzed. Results: Among 38 patients, the total seropositive rate for IgM and IgG was 50.0% and 92.1%, respectively. Two patients remained seronegative throughout the course of illness. In the early phase of illness, the RNA test for sputum specimens possessed the highest detectability(92.3%), followed by the the RNA test for throat swabs (69.2%), and the antibodies assays presented lower positive rates(IgM, 23.0%, IgG, 53.8%). While, the sensitivity of antibodies assays overtook that of RNA test since day 8 after onset (IgM, 50.0%; IgG, 87.5%). Of note, the positive rate of throat swabs was only 13.0% for cases in later phase(≥15 d.a.o), and the sensitivities of IgM and IgG rose to 52.2% and 91.3%, respectively. Combined use of antibodies assay and qRT-PCR at the same time was able to improve the sensitivities of pathogenic-diagnosis, especially for the throat swabs group at the later stage of illness. Moreover, most of these cases with undetectable viral RNA in throat swabs specimens at the early stage of illness were able to be IgM/IgG seropositive after 7 days. Conclusions: The antibodies detection against SARS-CoV-2 offers vital clinical information for physicians, and could be used as an effective supplementary indicator for suspected cases of negative viral nucleic acid detection or in conjunction with nucleic acid detection in the diagnosis of suspected cases.

Zinc oxide (ZnO) phosphors with highly efficient green emission have been prepared by calcining ZnS with NH4Br as additive in air atmosphere. The luminescent properties of as-prepared ZnO phosphors were characterized by X-ray photoelectron spectroscopy and photoluminescence. Our results reveal that the green emission is ascribed to a transition of a photo-generated electron from the localized defect centers (Vo+) to a deeply trapped hole (VZn−) within the band gap. The addition of NH4Br enhances the luminescent emission of ZnO by promoting the formation of vacancies of both oxygen and zinc.

Background and Aims Leaf area index (LAI) is one of the most important crop parameters in photosynthesis driven crop growth simulation models. Temperature and radiation are important climate factors affecting crop leaf growth. The aim of this study is to quantitatively investigate the effects of both temperature and photosynthetically active radiation (PAR) on the leaf growth of greenhouse cucumber (Cucumis sativus). Methods Experiments with different cultivars and sowing dates were conducted in greenhouses of Shanghai Academy of Agricultural Sciences during August,2003 and July,2004. We used the following quantitative relationships based on experimental data to model the relationship between the product of thermal effectiveness and PAR (TEP): accumulated TEP to the number of unfolding leaves per plant and the number of old leaves removed per plant,leaf position relative to the rate of increase in leaf length and the maximum leaf length; and the ratio of leaf area to leaf length. Based on these quantitative relationships,a leaf area simulation model for greenhouse cucumber was developed. Independent experimental data were used to validate the model. The simulated results of the model developed in this study were compared with those of the traditional GDD based model (which predict leaf area based on growing degree days) and SLA based model (which predict leaf area based on the specific leaf area and leaf dry weight). Key Results The coefficient of determination (R2) and the root mean squared error (RMSE) between the simulated and the measured leaf area index (LAI) based on the 1∶1 line are 0.879 2 and 0.398 0,respectively. The prediction accuracy of this model is 37% and 74% higher,respectively,than that of the traditional GDD and SLA based models. Conclusions The model developed in this study can predict LAI satisfactorily using air temperature,radiation,date of the first leaf unfolding and planting density. The simple model input makes the model user friendly and more applicable in greenhouse crop and climate management practices.

Y2O3 nanoparticles doped with different concentrations of Er3+ were prepared by the co-precipitation method. X-ray diffraction and transmission electron microscopy results show that Er3+ dissolves completely in the Y2O3 cubic phase. The Er3+:Y2O3 nanoparticles are homogeneous in size and nearly spherical, and the average diameter of the particles after being calcined at 1,000 °C for 2 h is in the range of 40–60 nm. When Er3+:Y2O3 nanoparticles are excited under a 980 nm diode laser, there are two main emission bands: green emission centered at 562 nm corresponding to the 4S3/2/2H11/2 → 4I15/2 radiative transitions and red emission centered at 660 nm corresponding to the 4F9/2 ∼ 4I15/2 radiative transitions. By changing the doping concentration of Er3+ ions, the up-conversion luminescence can be gradually tuned from green to red.

Greenings had been considered as potential measure in mitigating the urban thermal environment conditions. In this paper, three types of urban land including asphalt road under the sun, grassland under the sun, asphalt road under the shade of adult Indus-tree were selected to measure the air temperature (1.5m height) and land surface temperature, the role of different type of urban greenings in moderating the thermal environment were compared. The results showed that adult Indus-tree had distinct cooling effect during the day and had insulating effect at night, that grassland had cooling effect in the day, but the cooling capacity was lower than that of adult Indus-tree during the day for the thermal environment at 1.5m height. For the surface thermal environment, the role of decreasing temperature of adult Indus-tree was higher than that of grassland during the day, It was inverse at night, and the land surface temperature of asphalt road under the shade of adult Indus-tree was higher than that of asphalt road under the sun in the day except 1∼2 hours in the early morning; the land surface temperature of grassland is obviously lower than asphalt road under the sun at night, and intensity was stronger than that of the shade of adult Indus-tree.

Y2O3 nanoparticles doped with different concentrations of Er3+ were prepared by the co-precipitation method. X-ray diffraction and transmission electron microscopy results show that Er3+ dissolves completely in the Y2O3 cubic phase. The Er3+:Y2O3 nanoparticles are homogeneous in size and nearly spherical, and the average diameter of the particles after being calcined at 1,000 degrees C for 2 h is in the range of 40-60 nm. When Er3+:Y2O3 nanoparticles are excited under a 980 nm diode laser, there are two main emission bands: green emission centered at 562 nm corresponding to the 4S3/2/2H11/2 --4115/2 radiative transitions and red emission centered at 660 nm corresponding to the 4F9/2 --4I15/2 radiative transitions. By changing the doping concentration of Er3+ ions, the up-conversion luminescence can be gradually tuned from green to red.