We report acute antibody responses to SARS-CoV-2 in 285 patients with COVID-19. Within 19 days after symptom onset, 100% of patients tested positive for antiviral immunoglobulin-G (IgG). ...Seroconversion for IgG and IgM occurred simultaneously or sequentially. Both IgG and IgM titers plateaued within 6 days after seroconversion. Serological testing may be helpful for the diagnosis of suspected patients with negative RT-PCR results and for the identification of asymptomatic infections.
To investigate the change in the prevalence of reduced visual acuity (VA) in Taiwanese school children after a policy intervention promoting increased time outdoors.
Prospective cohort study based on ...the Taiwan School Student Visual Acuity Screen (TSVAS) by the Ministry of Education in Taiwan.
All school children from grades 1 through 6 were enrolled in the TSVAS from 2001 through 2015.
The TSVAS requires each school in Taiwan to perform measurements of uncorrected VA (UCVA) on all students in grades 1 through 6 every half year using a Tumbling E chart. Reduced VA was defined as UCVA of 20/25 or less. Data from 1.2 to 1.9 million primary school children each year were collected from 2001 through 2015. A policy program named Tian-Tian 120 encouraged schools to take students outdoors for 120 minutes every day for myopia prevention. It was instituted in September 2010. To investigate the impact of the intervention, a segmented regression analysis of interrupted time series was performed.
Prevalence of reduced VA.
From 2001 to 2011, the prevalence of reduced VA of school children from grades 1 through 6 increased from 34.8% (95% confidence interval CI, 34.7%–34.9%) to 50.0% (95% CI, 49.9%–50.1%). After the implementation of the Tian-Tian 120 outdoor program, the prevalence decreased continuously from 49.4% (95% CI, 49.3%–49.5%) in 2012 to 46.1% (95% CI, 46.0%–46.2%) in 2015, reversing the previous long-term trend. For the segmented regression analysis controlling for gender and grade, a significant constant upward trend before the intervention in the mean annual change of prevalence was found (+1.58%; standard error SE, 0.08; P < 0.001). After the intervention, the trend changed significantly, with a constant decrease by –2.34% annually (SE, 0.23; P < 0.001).
Policy intervention to promote increased time outdoors in schools was followed by a reversal of the long-term trend toward increased low VA in school children in Taiwan. Because randomized trials have demonstrated outdoor exposure slowing myopia onset, interventions to promote increased time outdoors may be useful in other areas affected by an epidemic of myopia.
Despite significant advances in the fabrication and applications of graphene-like materials, it remains a challenge to prepare single-layered metallic materials, which have great potential ...applications in physics, chemistry and material science. Here we report the fabrication of poly(vinylpyrrolidone)-supported single-layered rhodium nanosheets using a facile solvothermal method. Atomic force microscope shows that the thickness of a rhodium nanosheet is <4 Å. Electron diffraction and X-ray absorption spectroscopy measurements suggest that the rhodium nanosheets are composed of planar single-atom-layered sheets of rhodium. Density functional theory studies reveal that the single-layered Rh nanosheet involves a δ-bonding framework, which stabilizes the single-layered structure together with the poly(vinylpyrrolidone) ligands. The poly(vinylpyrrolidone)-supported single-layered rhodium nanosheet represents a class of metallic two-dimensional structures that might inspire further fundamental advances in physics, chemistry and material science.
This research conducts an empirical study on arbitrage opportunities in the crude oil futures market of Shanghai International Energy Exchange in the period of China’s economic change, 2020–2022. We ...use the daily closing price data of crude oil futures sc2303 and sc2212 to test whether there is a statistical arbitrage opportunity in China’s crude oil futures market. Taking the most commonly used 12 + 6 rolling window mode in statistical arbitrage, we select several one-year periods that pass the cointegration test during the formation period and apply the optimal opening, closing, and stop loss thresholds based on the highest yield during the formation period to the trading period. Finally, we draw the following conclusions: (i) the pair trading strategy based on the cointegration model is profitable in China’s crude oil futures market; (ii) the 12 + 6 window model can be applied to the pair trading strategy based on China’s crude oil futures. Our research proves the effectiveness of pair trading strategy in China’s crude oil futures market for institutional and individual investors.
Tylophorine-based compounds and natural cardiotonic steroids (cardenolides and bufadienolides) are two classes of transmissible gastroenteritis coronavirus inhibitors, targeting viral RNA and host ...cell factors, respectively. We tested both types of compounds against two types of coronaviruses, to compare and contrast their antiviral properties, and with view to their further therapeutic development. Examples of both types of compounds potently inhibited the replication of both feline infectious peritonitis virus and human coronavirus OC43 with EC
values of up to 8 and 16 nM, respectively. Strikingly, the tylophorine-based compounds tested inhibited viral yields of HCoV-OC43 to a much greater extent (7-8 log magnitudes of p.f.u./ml) than the cardiotonic steroids (about 2-3 log magnitudes of p.f.u./ml), as determined by end point assays. Based on these results, three tylophorine-based compounds were further examined for their anti-viral activities on two other human coronaviruses, HCoV-229E and SARS-CoV-2. These three tylophorine-based compounds inhibited HCoV-229E with EC
values of up to 6.5 nM, inhibited viral yields of HCoV-229E by 6-7 log magnitudes of p.f.u./ml, and were also found to inhibit SARS-CoV-2 with EC
values of up to 2.5-14 nM. In conclusion, tylophorine-based compounds are potent, broad-spectrum inhibitors of coronaviruses including SARS-CoV-2, and could be used for the treatment of COVID-19.
A novel N-doped activated carbon (NAC) derived from shaddock peel was investigated to remove norfloxacin (NFX) from aqueous solution. The Box-Behnken central composite design (BBD) was used to ...optimize the preparation conditions of NAC. The specific surface area of NAC was 2,481.81 m
g
, which was obtained at 1,106 K activation temperature, 2.4 h residence time, and 2.3:1 mass ratio of KOH to hydrochar. Moreover, the equilibrium data were perfectly represented by Langmuir and Koble-Corrigan isotherms, and the adsorption process was precisely described by the pseudo-second-order kinetic model. Besides, the adsorption of NFX on NAC was mainly controlled by π-π electron-donor-acceptor (EDA) interaction, hydrophobic effect, hydrogen-bonding, electrostatic interaction and Lewis acid-base effect. The maximum monolayer adsorption capacity of NFX was 746.29 mg g
at 298 K, implying that NAC was a promising adsorbent for the removal of NFX from aqueous solution.
In this work, we constructed a novel electrochemiluminescent (ECL) strategy based on sandwich immunoassay-induced target transformation assisted with catalyzed hairpin assembly (CHA) amplification ...for ultrasensitive bioassay with cysteine-rich protein 61 (CCN1) as a model. First, the target CCN1 could be equally transformed into the specific oligonucleotide (initiator I) labeled on the detection antibody based on the specific sandwich immunoassay. In addition, the initiator I triggered an efficient nonenzymatic CHA amplification in the presence of ferrocene-labeled hairpin 1 (Fc-H1) and hairpin 2 (H2) to produce massive hybrids (Fc-H1–H2) containing a sticky end labeled with ferrocene. Finally, Fc-H1–H2 could be immobilized on the capture probe single-stranded DNA (ssDNA)-modified electrode through the hybridization between the sticky end of Fc-H1–H2 and ssDNA, and a significantly quenched ECL signal could be obtained due to the efficient quench effect between ferrocene and the ECL indicator, ruthenium(II) tris(4,4′-dicarboxylicacid-2,2′-bipyridyl) Ru(dcbpy)3 2+, immobilized on the surface of the electrode, which was related to the concentration of target CCN1. As expected, the proposed ECL biosensor exhibited a relatively low detection limit of 3.9 fg/mL in a linear range from 10 fg/mL to 100 ng/mL. This ECL strategy inspired the clinical examination of the biomarker CCN1, providing potential application in early diagnosis and malignant monitoring of cancer.
Green synthesis of metal nanoparticles using plant extracts as an effective bio-reducing reagent has attracted considerable attention. Fe/Cu nanocomposites synthesized by extracts of sweet potato ...leaves served to remove basic magenta (BM) from aqueous solution. The adsorption operation conditions of BM on Fe/Cu nanocomposites were optimum by Box-Behnken design (BBD) model of response surface methodology (RSM). The adsorption equilibrium data were well described by the Sips and Redlich-Peterson models. The thermodynamic studies showed that the adsorption process was endothermic and spontaneous. The maximum adsorption capacity from the Sips model was 235.92 mg/g at 298 K, which indicated that Fe/Cu nanocomposites had potential application in wastewater treatment. As indicated by pseudo-second order kinetics model, the adsorption of BM onto Fe/Cu nanocomposites could be achieved through the complexation, H-bonding,
π
-
π
adsorbate-adsorbent interaction, and electrostatic interaction at different pH values.
It was demonstrated in previous studies that cysteine-rich angiogenic inducer 61 (Cyr61) plays vital roles in hematological disorders, and we have already reported that the Cyr61 protein is a tumor ...promoter in acute myeloid leukemia (AML). Here, we investigated the association between CYR61 gene polymorphisms and susceptibility to AML.We genotyped 2 single-nucleotide polymorphisms (rs2297141 and rs6576776) in the region of the CYR61 gene by improved multiplex ligase detection reaction genotyping assays in a total of 275 samples, including samples from 137 AML patients and 138 healthy controls. Chi-squared tests and logistic regression analysis were performed to compare the different distributions of the genotypes and alleles between patients and healthy controls.The rs2297141 A allele was associated with lower risk of AML compared with the G allele (odds ratio OR = 0.704, 95% confidence interval CI = 0.503-0.985, P = .04) in both the dominant (OR = 0.447, 95% CI = 0.22-0.909, P = .025, AA vs GG) and recessive inheritance models (OR = 0.419, 95% CI = 0.23-0.763, P = .004, AA vs GA + GG). Although the distribution of the rs6576776 alleles was not different between patients with AML and normal controls, the CC genotype significantly increased the risk of AML in the dominant inheritance model (OR = 6.064, 95% CI = 1.303-28.216, P = .01, CC vs GG) and the recessive inheritance model (OR = 5.937, 95% CI = 1.291-27.306, P = .01, CC vs GC + GG). Additionally, it was shown that the rs2297141 and rs6576776 genotypes were associated with AML-M5 and AML-M2, respectively.Our findings indicated that genetic polymorphisms in the CYR61 gene may be considered potential AML risk factors in the Han Chinese population.
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