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ABSTRACT: Background: As several vaccines for SARS-CoV-2 have been developed, a large proportion of individuals have been vaccinated worldwide so far. The rapid and accurate immunoassays are urgently needed for detecting the specific virus-neutralizing antibody (NAb), which reflect the protective effect of the vaccines among different populations. Methods: In this study, we designed a quantum dot lateral flow immunoassay strip (QD-LFIA) for smartphones for the detection of specific IgG or neutralizing antibodies in SARS-CoV-2 in human serum or whole blood samples. The recombinant receptor binding domain of the SARS-CoV-2 spike protein was used as the antigen to combine with NAb or angiotensin-converting enzyme 2. Results: Among 81 patients who recovered from COVID-19 who were diagnosed using the nucleic acid test initially, 98.8% (80/81) were positive for IgG and 88.9% (72/81) were positive for NAb by QD-LFIA. Among 64 individuals inoculated with inactivated vaccines and six subunit vaccines, 90% (63/70) were positive for IgG and 82.9% (58/70) were positive for NAb by QD-LFIA, whereas no cross-reaction was found in 150 healthy blood donors, two patients with influenza B, and three patients with common cold. Conclusion: The established platform could achieve a rapid and accurate detection of NAb specific to SARS-CoV-2, which could be used for detecting the protective effect of the vaccines in areas of world that currently affected by the pandemic.

The Yangzhuang iron deposit is a Kiruna-type iron oxide-apatite (IOA) deposit within the Ningwu mining district of the Middle and Lower Yangtze River Metallogenic Belt (MLYRMB), China. This study applies a numerical modeling approach to identify the key processes associated with the formation of the deposit that cannot be easily identified using traditional analytical approaches, including the duration of the mineralizing process and the genesis of iron orebodies within intrusions associated with the deposit. This approach highlights the practical value of numerical modeling in quantitatively analyzing mineralizing processes during the formation of mineral deposits and assesses how these methods can be used in future geological research. Our numerical model links heat transfer, pressure, fluid flow, chemical reactions, and the movement of ore-forming material. Results show that temperature anomaly and structure (occurrence of the contact of intrusion and the Triassic Xujiashan group) are two key factors controlling the formation of the Yangzhuang deposit. This modeling also indicates that the formation of the Yangzhuang deposit only took some 8000 years, a reaction that is likely to be controlled by temperature and diffusion rates within the system. The dynamic changes of temperature and the distribution of mineralization also indicate that the orebodies located inside the intrusions most likely formed after magma ascent rather than representing blocks of existing mineralization that descended into the magma as a result of stoping or other similar processes. All these data form the basis for future research into the forming processes of Kiruna-type IOA systems as well as magmatic–hydrothermal systems more broadly, including providing useful insights for future exploration for these systems. The simulation approach used in this study has several limitations, such as oversimplified chemical reactions, uncertainty of pre-metallogenic conditions and limitation of 2D model. Future development into both theories and methods will definitely improve the practical significance of numerical simulation of ore-forming processes and provide quantitative results for more geological issues.

Adult hearts are hard to recover after cardiac injury due to the limited proliferative ability of cardiomyocytes. Emerging evidence indicates the induction of cell cycle reentry of cardiomyocytes by special treatment or stimulation, which offers adult heart regenerative potential. Herein, a microRNA (miRNA) screening in cardiomyocytes identified miR-301a enriched specially in the neonatal cardiomyocytes from rats and mice. Overexpression of miR-301a in primary neonatal cardiomyocytes and H9C2 cells induced G1/S transition of the cell cycle, promoted cellular proliferation, and protected cardiomyocytes against hypoxia-induced apoptosis. Adeno-associated virus (AAV)9-mediated cardiac delivery of miR-301a to the mice model with myocardial infarction (MI) dramatically promoted cardiac repair post-MI in vivo. Phosphatase and tensin homolog (PTEN)/phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway was confirmed to mediate miR-301a-induced cell proliferation in cardiomyocytes. Loss of function of PTEN mimicked the miR-301a-induced phenotype, while gain of function of PTEN attenuated the miR-301a-induced cell proliferation in cardiomyocytes. Application of RG7440, a small molecule inhibitor of AKT, blocked the function of miR-301a in cardiomyocytes. The current study revealed a miRNA signaling in inducing the cell cycle reentry of cardiomyocytes in the injured heart, and it demonstrated the miR-301a/PTEN/AKT signaling as a potential therapeutic target to reconstitute lost cardiomyocytes in mammals.

Fine particulate matter (PM2.5) threatens public health severely, which, luckily, can be governed by referring to its spatiotemporal distribution and key driving factors. However, very few explored it in the long-term, broadly, and systematically. In this study, nine Chinese key urban agglomerations were targeted to explore the spatial distribution of PM2.5 and the evolution of its major driving factors from 2000 to 2017. Spatiotemporal distribution and change tendency were evaluated by spatial autocorrelation analysis and dynamic time warping (DTW), and the entire research period was divided into four stages according to the evaluation. Subsequently, the geographical detector method (GDM) was adopted to quantify the relationship between anthropogenic and meteorological factors with PM2.5 concentration in the entire period and sub-stages. As the findings indicate: 1) In 2000–2017, PM2.5 concentration increased firstly in all agglomerations and then declined by fluctuation; it was mainly gathered in the plain areas where the core cities of urban agglomerations were located, with the highest concentration in North China. 2) Variation of PM2.5 concentration appeared similar tendency and regional aggregation, e.g., five urban agglomerations around the central plains urban agglomeration (CPUA) had similar patterns. 3) The Driving factors of PM2.5 showed noticeable spatiotemporal differences. It is indicated that the critical meteorological factors refer to temperature and air pressure, while the key anthropogenic factors are population density (PD) and road density (RD). Except for the population density showing a relatively persistent high influence on urban agglomeration, especially significant in northern China, the rest of the anthropogenic factors represented different characteristics. Specifically, the proportion of secondary industry (PSP) and gross domestic product per capita (GDPP) showed relatively strong effects in the early stage but weakening dramatically in the later stage. Foreign direct investment (FI) increased in developed urban agglomerations in the entire stage while showed a downward trend in underdeveloped cities. Road density was enhanced dramatically in the early stage but weakened slowly in the later stage. The findings reveal the change tendency of PM2.5 concentration in urban agglomerations and the evolution of its driving factors, which help the Chinese government adopt effective strategies to cope with pollution.