COVID-19 is a widespread and highly contagious disease in the human population. COVID-19 is caused by SARS-CoV-2 infection. There is still a great demand for point-of-care tests for detection, ...epidemic prevention and epidemiological investigation, both now and after the epidemic. We present a lateral flow immunoassay kit based on a selenium nanoparticle-modified SARS-CoV-2 nucleoprotein, which detects anti-SARS-CoV-2 IgM and anti-SARS-CoV-2 IgG in human serum, and the results can be read by the naked eye in 10 minutes. We expressed and purified the SARS-CoV-2 nucleoprotein in HEK293 cells, with a purity of 98.14% and a concentration of 5 mg mL-1. Selenium nanoparticles were synthesized by l-ascorbic acid reduction of seleninic acid at room temperature. After conjugation with the nucleoprotein, a lateral flow kit was successfully prepared. The IgM and IgG detection limits of the lateral flow kit reached 20 ng mL-1 and 5 ng mL-1, respectively, in human serum. A clinical study sample comprising 90 COVID-19-diagnosed patients and 263 non-infected controls was used to demonstrate a sensitivity and specificity of 93.33% and 97.34%, respectively, based on RT-PCR and clinical results. No cross-reactions with rheumatoid factor and positive serum for anti-nuclear antibodies, influenza A, and influenza B were observed. Moreover, the lateral flow kit remained stable after storage for 30 days at 37 °C. Our results demonstrate that the selenium nanoparticle lateral flow kit can conveniently, rapidly, and sensitively detect anti-SARS-CoV-2 IgM and IgG in human serum and blood; it can also be suitable for the epidemiological investigation of COVID-19.
Heavy metal contamination in soil has attracted great attention worldwide. In situ stabilization has been considered an effective way to remediate soils contaminated by heavy metals. In the present ...research, a multiple-modified biochar (BCM) was prepared to stabilize Cd and Cu contamination in two different soils: a farmland soil (JYS) and a vegetable soil (ZZS). The results showed that BCM was a porous-like flake material and that modification increased its specific surface area and surface functional groups. The incubation experiment indicated that BCM decreased diethylenetriaminepentaacetic (DTPA)-extractable Cd and Cu by 92.02% and 100.00% for JYS and 90.27% and 100.00% for ZZS, respectively. The toxicity characteristic leaching procedure (TCLP)-extractable Cd and Cu decreased 66.46% and 100.00% for JYS and 46.33% and 100.00% for ZZS, respectively. BCM also reduced the mobility of Cd and Cu in soil and transformed them to more stable fractions. In addition, the application of BCM significantly increased the soil dehydrogenase, organic matter content and available K (p < 0.05). These results indicate that BCM has great potential in the remediation of Cd- and Cu-contaminated soil.
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•Multiple modifications improved the specific surface area and surface active groups of biochar.•BCM efficiently reduced the bioavailability Cd and Cu.•BCM reduced the leachability of Cd and Cu.•BCM transformed Cd and Cu to a more stable fraction.•BCM improved the properties of Cd- and Cu-contaminated soils.
Lateral flow assay is widely used in the point-of-care testing on-site and in-home testing with the advantage of being simple, rapid, sensitive and cost-effective. Proper labels are the key factors ...in lateral flow assay. Traditional labels include colloidal gold, selenium nanoparticle, and carbon nanoparticle, among which the colloidal gold is most commonly used. Lateral flow assay has been improved as a result of the discovery of new labels, such as quantum dots and nanozyme recently. Meanwhile, transformation of qualitative detection to quantitative detection is gradually realized. This article aims at introducing the most often used and the latest lateral flow assay labels, providing a basis theoretical investigation on screening proper labels for lateral flow assay researchers.
1,25‐dihydroxyvitamin D3 (1,25(OH)2D3, VitD3) is the major active ingredient of vitamin D and has anti‐inflammatory activity; however, the mechanism for this remains poorly understood. In this study, ...we found that VitD3 was able to abolish NOD‐like receptor protein 3 (NLRP3) inflammasome activation and subsequently inhibit caspase‐1 activation and IL‐1β secretion via the vitamin D receptor (VDR). Furthermore, VitD3 specifically prevented NLRP3‐mediated apoptosis‐associated speck‐like protein with a caspase‐recruitment domain (ASC) oligomerization. In additional to this, NLRP3 binding to NIMA‐related kinase 7 (NEK7) was also inhibited. Notably, VitD3 inhibited autophagy, leading to the inhibition of the NLRP3 inflammasome. Uncoupling protein 2‐reactive oxygen species signaling may be involved in inflammasome suppression by VitD3. Importantly, VitD3 had both preventive and therapeutic effects on mouse model of ulcerative colitis, via inhibition of NLRP3 inflammasome activation. Our results reveal a mechanism through which VitD3 represses inflammation and prevents the relevant diseases, and suggest a potential clinical use of VitD3 in autoimmune syndromes or other NLRP3 inflammasome‐driven inflammatory diseases.
VitD3 represses inflammation and prevents its related outcomes, suggesting a potential clinical use for VitD3 in autoimmune syndromes or other NLRP3 inflammasome‐driven inflammatory diseases.
Since a tactical electromagnetic railgun system is required to fire several times a minute, the thermal load on the rails leads to a higher temperature, which will even result in launch failures and ...reduce the life span of the launcher. In this paper, the rail temperature was measured during the launch experiment. Furthermore, based on a 3-D transient model with moving armature, mechanically, thermally coupled electromagnetic field analysis using finite-element method is presented. The Joule heating is one of the main heat sources in the rails. Contact resistance and friction force that cause heat between the armature and the rail are also included in the model. The simulation results show that the peak temperature in the rail occurs at the inner surface. Overall, along the direction of armature motion, the temperature of the rail near the breech end is higher than at the muzzle end, and the maximum temperature on the rail appears near the initial position of the armature. The contact resistance contributes much more than friction to the temperature rise in rails.
The success of arsenic trioxide (ATO) in treatment of acute promyelocytic leukemia (APL) attracts a great deal of attention to researchers to explore its activity of anti-leukemia. However, ATO has ...unavailable effect on chronic myeloid leukemia (CML), especially multidrug resistant (MDR)-CML, unless using high concentration. Realgar (As4S4) has been employed in Chinese traditional medicine for 1500 years. Research evidences confirmed realgar has similar effect on treating with APL as ATO, but the problem of large dose and long period in the CML/MDR-CML treatment still exist. By using a microbial leaching process with Acidithiobacillus ferrooxidans, we obtained realgar transforming solution (RTS) which showed significantly higher extent in inhibiting CML cell line K562 and MDR-CML cell line K562/ADM, and then trigger apoptosis. Both K562 and K562/ADM showed arsenic-dose-dependent effect on RTS. Interestingly, the overexpression of MDR1 mRNA and P-glucoprotein (P-gp) in K562/ADM cells were down-regulated by RTS, where there are no obvious effects on ATO and realgar and arsenic can be subsequently accumulated in K562/ADM cells efficiently. The intracellular accumulation of arsenic in K562/ADM cells treated with RTS for 4 h was 2-fold and 16-folds higher than those treated with realgar or ATO. Meanwhile, Western blot analysis of AQP9, the main transporter of arsenic, was increased by RTS treatment particularly in K562/ADM. Thus, these results suggested that the effect from a certain arsenical or a variety of arsenicals in RTS might be a promising candidate both for treating CML/MDR-CML alone and as combinations with currently used anti-CML/MDR-CML drug, although arsenical forms in RTS are undefined.
The emergence of SARS-CoV-2 has seriously affected the lives of people worldwide. Clarifying the attenuation rule of SARS-CoV-2 neutralizing antibody (NAb) in vivo is the key to prevent reinfection ...and recurrence of virus. Currently, the commonly used methods for detecting NAb include virus neutralization tests, pseudovirus neutralization assays, lateral flow immunochromatography and enzyme-linked immunosorbent assays. The detection of NAb not only can be used to evaluate the level of immunity after vaccination or infection but also can provide important theoretical support for virus reinfection, recurrence and vaccine iteration. In this research, the related technologies of SARS-CoV-2 NAb detection were reviewed, aiming to provide better research ideas for SARS-CoV-2 epidemic prevention and control.
SARS-CoV-2 neutralizing antibody (NAb) in vivo is the key to prevent reinfection and recurrence of virus. Currently, the commonly used methods for detecting NAb include virus neutralization tests, pseudovirus neutralization assays, lateral flow im-munochromatography and enzyme-linked immunosorbent assays. The detection of NAb not only be used to evaluate the level of immunity after vaccination or infection but also can provide important theoretical support for virus reinfection, recurrence and vaccine iteration. Display omitted
•NAb is the key to prevent reinfection and recurrence of SARS-CoV-2.•Clarifying the decline pattern requires effective NAbs detection methods.•It is important to clarify the objective circumstances of various methods.
NLRP3 inflammasome activation plays an important role in diabetic cardiomyopathy (DCM), which may relate to excessive production of reactive oxygen species (ROS). Gypenosides (Gps), the major ...ingredients of Gynostemma pentaphylla (Thunb.) Makino, have exerted the properties of anti‐hyperglycaemia and anti‐inflammation, but whether Gps improve myocardial damage and the mechanism remains unclear. Here, we found that high glucose (HG) induced myocardial damage by activating the NLRP3 inflammasome and then promoting IL‐1β and IL‐18 secretion in H9C2 cells and NRVMs. Meanwhile, HG elevated the production of ROS, which was vital to NLRP3 inflammasome activation. Moreover, the ROS activated the NLRP3 inflammasome mainly by cytochrome c influx into the cytoplasm and binding to NLRP3. Inhibition of ROS and cytochrome c dramatically down‐regulated NLRP3 inflammasome activation and improved the cardiomyocyte damage induced by HG, which was also detected in cells treated by Gps. Furthermore, Gps also reduced the levels of the C‐reactive proteins (CRPs), IL‐1β and IL‐18, inhibited NLRP3 inflammasome activation and consequently improved myocardial damage in vivo. These findings provide a mechanism that ROS induced by HG activates the NLRP3 inflammasome by cytochrome c binding to NLRP3 and that Gps may be potential and effective drugs for DCM via the inhibition of ROS‐mediated NLRP3 inflammasome activation.
In previous studies, the armature-rail sliding contact interface is usually considered to be an ideal slide in which both rails are parallel and symmetric. However, due to the influence of structural ...deformation of the barrel affected by boundary constraints and the manufacturing errors of rails and armature, it often leads to a variety of nonideal the armature-rail matching such as space curved or twisted rails, offset or deflected armature, and so on. This article focuses on the common vertical curved rail in electromagnetic railgun. By introducing centrifugal force effects and coupling electromagnetic force, the armature-rail contact pressure is analyzed theoretically. According to the 3-D finite-element simulation results, the effect of centrifugal force on sliding contact pressure should not be ignored. The effects of different curved radii, velocities, and densities of armature on the contact pressure are compared and analyzed. The influence law on the contact pressure is obtained, which provides a theoretical basis for the design of the railgun.
•Selenium nanoparticle (SeNp) of 40.78 nm was synthesized successfully with SDS and PEG.•The SeNp was spherical form and uniform dispersion.•SeNp can be used for clenbuterol detection by lateral flow ...immunoassay (LFIA).•The SeNP-based LFIA can be stored at 37 °C for 60 days.
Lateral flow immunoassays (LFIAs) have been applied widely in clinical diagnosis, food safety, drug abuse, environmental monitoring and other fields due to their characteristics of rapidity, sensitivity, stability and low cost. Choosing the proper labels is key to the preparation of LFIAs. An ideal probe requires a simple synthesis, has stable performance and is economical. This study aimed to establish a simple, rapid and convenient method for the preparation of selenium nanoparticles (SeNPs) that can be used as labels in LFIAs. Appropriate SeNPs were successfully prepared by reducing 2 mM H2SeO3 with 16 mM l-ascorbic acid (Vc), 5 mM sodium dodecyl sulfate (SDS) and 100 mM polyethylene glycol (PEG) as stabilizing agents. The spherically formed and uniformly dispersed nanoparticles were applied to the preparation of an LFIA. In this study, the preparation of the SeNPs was economical and was accomplished at room temperature. We used clenbuterol (CLE) as an analyte in an LFIA; the limit of detection (LOD) of CLE in pig urine was found to be 3 ng/mL, which meets the industry standard and has the same sensitivity as commercially available flow assays. In addition, the SeNP-based LFIA can be stored at 37 °C for 60 days.
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