One-Stop Extraction and In Situ RT-qPCR for Ultrasensitive Detection of Highly Diluted SARS-CoV-2 in Large-Volume Samples from Aquatic Environments.

Surveillance of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in aquatic environments attracted attention due to its considerable impacts on human health and ecology, especially in countries with poor sanitation standards. Based on a strategy of one-stop extraction and in situ amplification, we developed an ultrasensitive method that uses a polyacrylamide derivative-modified filter disc (PAD-FD), in which highly diluted RNA can be efficiently concentrated onto the filter disc and directly used for amplification. A newly designed spin column with a cup-like filter base facilitated the non-contact transfer of the affinity filter disc from the column to a PCR tube. The limit of detection of the PAD-FD coupled with RT-qPCR is 10 copies/mL. Using 32 suspected SARS-CoV-2 samples, we demonstrated that the detection rate of our method (62.5%, 20/32) was triple the rate of the commercial kit (18.8%, 6/32). Using a PAD-FD, 56.3% (18/32) and 40.6% (13/32) of the 10-fold-dilution samples with river and tap water, respectively, were detected. Even when diluted 100-fold, 28.1% (9/32) and 37.5% (12/32) were still detected in river and tap water, respectively. We believe that the PAD-FD method offers an accurate testing tool for monitoring viral RNA in aquatic environments, contributing to the forewarning of the SARS-CoV-2 outbreak and the breaking of the transmission chain.

An ultrasensitive and rapid "sample-to-answer" microsystem for on-site monitoring of SARS-CoV-2 in aerosols using "in situ" tetra-primer recombinase polymerase amplification.

Airborne transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted the urgent need for aerosol monitoring of SARS-CoV-2 to prevent sporadic outbreaks of COVID-19. The inadequate sensitivity of conventional methods and the lack of an on-site detection system limited the practical SARS-CoV-2 monitoring of aerosols in public spaces. We have developed a novel SARS-CoV-2-in-aerosol monitoring system (SIAMs) which consists of multiple portable cyclone samplers for collecting aerosols from several venues and a sensitive "sample-to-answer" microsystem employing an integrated cartridge for the analysis of SARS-CoV-2 in aerosols (iCASA) near the sampling site. By seamlessly combining viral RNA extraction based on a chitosan-modified quartz filter and "in situ" tetra-primer recombinase polymerase amplification (tpRPA) into an integrated microfluidic cartridge, iCASA can provide an ultra-high sensitivity of 20 copies/mL, which is nearly one order of magnitude greater than that of the commercial kit, and a short turnaround time of 25 min. By testing various clinical samples of nasopharyngeal swabs, saliva, and exhaled breath condensates obtained from 23 COVID-19 patients, we demonstrate that the positive rate of our system was 3.3 times higher than those of the conventional method. Combining with multiple portable cyclone samplers, we detected 52.2% (12/23) of the aerosol samples, six times higher than that of the commercial kit, collected from the isolation wards of COVID-19 patients, demonstrating the excellent performance of our system for SARS-CoV-2-in-aerosol monitoring. We envision the broad application of our microsystem in aerosol monitoring for fighting the COVID-19 pandemic.

A scalable microfluidic chamber array for sample-loss-free and bubble-proof sample compartmentalization by simple pipetting.

Sample compartmentalization is a pivotal technique in many bioanalytical applications, such as multiplex polymerase chain reaction (PCR) and digital PCR (dPCR). In this study, we successfully developed a novel self-compartmentalization device containing an array of microchambers, each of which is connected to a main microchannel with three capillary burst valves (CBVs) for fluid switching and partitioning. As these CBVs can be automatically opened in a predefined sequence, an incoming solution can be spontaneously directed into the chamber and held in place without further mixing. After that, either air or oil can be loaded into the main channel to isolate each chamber completely. By optimizing the relative burst pressures of the CBVs, a 100% sample utilization rate can be achieved even using a manual pipette and air bubbles in the sample cannot interfere with the loading. In addition, the number of the microchambers in an array can be easily scaled from a few to tens of thousands. To verify the feasibility of this self-compartmentalization method, we successfully conducted mock multiplex loop-mediated isothermal amplifications (LAMP) in an array that contains 144 microchambers, proving that our design method will provide a robust and versatile platform for various sample discretization purposes in the future.

Toxicological safety evaluation in acute and 28-day studies of aqueous extract from Bei-Qi-Wu-Jia formula.

ETHNOPHARMACOLOGICAL RELEVANCE: Bei Qi Wu Jia (BQWJ), a modern preparation of a traditional Chinese medicinal formula, is a combination of Radix Astragali and Acanthopanacis Senticosi. Although BQWJ has been used to treat insomnia, fatigue, and loss of appetite, toxicological safety studies are rare in the literature. AIM OF THE STUDY: To evaluate the acute and subacute toxicity of BQWJ extract after oral administration in mice and rats, respectively. MATERIALS AND METHODS: In the acute toxicity study, mice underwent oral administration of 67.5 g extract/kg/day. In the subacute toxicity study, rats underwent a single oral administration of 1.25, 2.5, 5.0, or 10.0 g/kg/day of BQWJ extract for 28 days. The animals' general behavior, body weight, food intake, biochemical and hematologic parameters, organ coefficients, and pathological morphology were analyzed. RESULTS: No evidence of toxicity was observed in the mice after acute exposure to BQWJ extract. The subacute results included no deaths and no changes in general behavior. Although BQWJ extract resulted in some significant changes in other parameters, these alterations cannot be considered treatment-related because they remained within normal ranges throughout the 28 days. CONCLUSIONS: In conclusion, the oral administration of BQWJ extract at doses of less than 67.5 g/kg/day for 1 day or 10.0 g/kg/day for 28 consecutive days can be considered safe and showed no distinct toxicity or side effects in this study.

The chloroplast genome of silk floss tree (Ceiba speciosa).

Ceiba speciosa (Malvaceae), also called silk floss tree, is a beautiful and deciduous tree native to tropical and subtropical forests of South America. Its phylogenetic position remains unclear. In this study, the complete chloroplast genome sequence of C. speciosa was reported. Its chloroplast genome size was 160,360 bp, which contains a small single copy (SSC) region of 19,947 bp and a large single copy region (LSC) of 89,393 bp, and two inverted repeats (IRs) of 25,510 bp each. In total, 129 genes were annotated for the chloroplast genome, including 86 protein-coding genes, 37 tRNA genes and 8 rRNA genes. Phylogenetic analysis showed that C. speciosa was sister to Bombax ceiba.

The contribution of the contingent negative variation (CNV) to goal maintenance.

The dot pattern expectancy (DPX) task has been strongly recommended as a measure of goal maintenance, which is impaired in schizophrenia patients. The current event-related potential (ERP) study was designed mainly to identify the ERP component that could represent the goal maintenance process of the DPX task as indexed by the error rate of the BX vs. AY (EBX-AY). We focused our analysis on the cue-phased contingent negative variation (CNV) and found a significant association between the EBX-AY and the amplitude of the difference wave of cue B vs. cue A (CNVB-A) (for CP3, ß=-0.262, P=0.001; for CPZ, ß=-0.184, P=0.025; for CP4, ß=-0.201, P=0.015). Lower EBX-AY (better goal maintenance) was correlated with larger CNVB-A. Further analysis found a significant association between the error rate of AY condition (EAY) and the amplitude of CNVA (for CP3, ß=-0.180, P=0.029; for CPZ, ß=-0.184, P=0.024; for CP4, ß=-0.208, P=0.011) and a significant association between the error rate of BX condition (EBX) and the amplitude of CNVB-A (for CP3, ß=-0.198, P=0.016; for CPZ, ß=-0.165, P=0.043; for CP4, ß=-0.151, P=0.066), but not the amplitude of the CNVB (all P>0.05). All these results together suggested that the cue-phased CNV could be used to represent the goal maintenance process. Future research needs to verify these results with schizophrenia patients.

Preparation and electrochemical performances of carbon sphere@ZnO core-shell nanocomposites for supercapacitor applications.

Carbon sphere (CS)@ZnO core-shell nanocomposites were successfully prepared through facile low-temperature water-bath method without annealing treatment. The morphology and the microstructure of samples were characterized by transition electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. ZnO nanoparticles with several nanometers in size decorated on the surface of the carbon sphere and formed a core-shell structure. Electrochemical performances of the CS@ZnO core-shell nanocomposites electrodes were investigated by cyclic voltammetry (CV) and galvanostatic charge/discharge (GDC). The CS@ZnO core-shell nanocomposite electrodes exhibit much larger specific capacitance and cycling stability is improved significantly compared with pure ZnO electrode. The CS@ZnO core-shell nanocomposite with mole ratio of 1:1 achieves a specific capacitance of 630 F g-1 at the current density of 2 A g-1. Present work might provide a new route for fabricating carbon sphere and transition metal oxides composite materials as electrodes for the application in supercapacitors.

Effect of rs1063843 in the CAMKK2 gene on the dorsolateral prefrontal cortex.

Recently, a single nucleotide polymorphism (SNP) in the CAMKK2 gene (rs1063843) was found to be associated with lower expression of the gene in the dorsolateral prefrontal cortex (DLPFC) and with schizophrenia (SCZ) and deficits in working memory and executive function. However, the brain mechanism underlying this association is poorly understood. A functional magnetic resonance imaging (fMRI) study (N = 84 healthy volunteers) involving multiple cognitive tasks, including a Stroop task (to measure attentional executive control), an N-back task (to measure working memory), and a delay discounting task (to measure decision making) to identify the brain regions affected by rs1063843 was performed. Across all three tasks, it was found that carriers of the risk allele consistently exhibited increased activation of the left DLPFC. In addition, the risk allele carriers also exhibited increased activation of the right DLPFC and the left cerebellum during the Stroop task and of the left caudate nucleus during the N-back task. These findings helped to elucidate the role of CAMKK2 in cognitive functions and in the etiology of SCZ. Hum Brain Mapp 37:2398-2406, 2016. © 2016 Wiley Periodicals, Inc.

Nanoparticle cluster gas sensor: Pt activated SnO2 nanoparticles for NH3 detection with ultrahigh sensitivity.

Pt activated SnO2 nanoparticle clusters were synthesized by a simple solvothermal method. The structure, morphology, chemical state and specific surface area were analyzed by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and N2-sorption studies, respectively. The SnO2 nanoparticle cluster matrix consists of tens of thousands of SnO2 nanoparticles with an ultra-small grain size estimated to be 3.0 nm. And there are abundant random-packed wormhole-like pores, caused by the inter-connection of the SnO2 nanoparticles, throughout each cluster. The platinum element is present in two forms including metal (Pt) and tetravalent metal oxide (PtO2) in the Pt activated SnO2 nanoparticle clusters. The as-synthesized pure and Pt activated SnO2 nanoparticle clusters were used to fabricate gas sensor devices. It was found that the gas response toward 500 ppm of ammonia was improved from 6.48 to 203.44 through the activation by Pt. And the results indicate that the sensor based on Pt activated SnO2 not only has ultrahigh sensitivity but also possesses good response-recovery properties, linear dependence, repeatability, selectivity and long-term stability, demonstrating the potential to use Pt activated SnO2 nanoparticle clusters as ammonia gas sensors. At the same time, the formation mechanisms of the unique nanoparticle clusters and highly enhanced sensitivity are also discussed.