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Bio-based hydrogels formed by the chemically or physically cross-links are promising materials in the biological system. In this paper, we propose a constitutive model within the framework of finite-strain viscoelasticity to investigate the mechanical behaviors of bio-based polyelectrolyte complex (PEC) hydrogels from the ionic complexation of sodium hyaluronate (HA)/chitosan with and without chemical crosslinkers. The structure of the viscoelastic constitutive model consists of a spring and a Kelvin element, in which two softening factors are adopted to represent the states of ionic bonds and bridges in the hydrogels. Based on some constitutive assumptions and through the conventional approach of thermodynamics, the constitutive equation system of the model is derived. Corresponding to the hydrogels with different crosslinker concentrations, the values of material parameters in the model are identified. To show the validity of the model, it is applied to simulate the mechanical behaviors of the hydrogel samples in the uniaxial tensile tests and cyclic loading–unloading tests. It is found that the model predictions can fit the experimental data quite well. Based on the modeling results, some further analyses regarding the effects of softening factors on the response of HA/chitosan hydrogels have also been conducted. • A viscoelastic model is proposed to study the mechanical behaviors of PEC hydrogels. • Two softening factors are adopted to represent the states of ionic bonds and bridges. • Parameters are identified for hydrogels with different crosslinker concentrations. • The mechanical response of PEC hydrogels can be predicted accurately by the model. • The effects of softening factors on the response of PEC hydrogels are analyzed. [ABSTRACT FROM AUTHOR]

Human sapovirus is regarded as an important viral agent for acute diarrhea worldwide. GII.8, a recently reported genotype, has been detected in a few countries and regions. In this study, we obtained the first genome sequence of a sapovirus GII.8 strain isolated in mainland China, and comprehensively analyzed the genetic diversity and evolutionary process of this genotype. The viral genome of the new GII.8 Guangzhou strain GZ2014-L231 comprised 7433 nucleotides, including two ORFs. Pairwise alignments of the new genome with representative sequences of different genotypes showed inconsistent homology between different protein-encoding regions, of which NS1 and VP2 were found as the variable proteins, and NS3, NS5, and NS6/7 were found as the conserved ones. Compared with other reported GII.8 genomes, the Guangzhou strain introduced 34 new nucleotide changes and one new amino acid change. Phylogenetic analysis based on full-length VP1 sequences demonstrated that 11 GII.8 strains could be divided into 4 clusters A-D, with 88 SNP and 10 SAP spots occurred during their evolutionary process. The Guangzhou strain has higher homology with seven GII.8 strain detected after 2014, especially the US and Peruvian strains of 2015/2016, which have the identical VP1 amino acid sequences. Using a Bayesian coalescent method based on VP1 sequences, GII.8 was predicted to emerge in 2001 with the evolution rate of 1.45 × 10−3 nucleotide substitutions/site/year (strict clock). In summary, the data in this study not only provided reference data from mainland China for sapovirus researches in future, but also firstly described the evolutionary process of the GII.8 genotype. • The first genome sequence of GII.8 SaV from mainland China was obtained and analyzed. • The new Guangzhou genome employed 34 new SNP and one new SAP. • NS1 and VP2 were found as the variable proteins in the SaV genome. • GII.8 SaV could be further divided into four clusters based on the capsid VP1. • TMRCA and evolution rate for the capsid VP1 gene of GII.8 SaV was estimated. [ABSTRACT FROM AUTHOR]

Abstract Noroviruses are the primary cause of non-bacterial acute gastroenteritis worldwide, and GII.8 belongs to a non-epidemic genotype with a limited understanding currently. In this study, we assembled the first GII.8 norovirus genome from China and clarified the temporal evolutionary process of this non-epidemic variant. Using the "4+1+1" application strategy with newly designed primer sets, the genome of one GII.8 strain GZ2017-L601 from China was firstly sequenced that comprised 7476 nucleotides. The homology of the new genome and the previous only GII.8 genome reached 93.8% identity at the nucleotide level, but only 10, 6, 7 amino acid mutations occurred in three ORFs. When compared the new strain with other GII reference strains, p22 and P2 were calculated as the variable encoding regions, and NTPase, VPg, 3CL, RdRp and S were shown as the conserved ones. We then reconstructed the evolutionary process of the GII.8 genotype using other available sequences in GenBank. Based on the partial N/C region, all GII.8 strains could be subdivided chronologically into four clusters, which spans 1967–1994, 1997–2005, 2003–2009, and 2007–2017, respectively. Moreover, differences of capsid P proteins between GII.8 strains and the epidemic GII.4 strain VA387 were also compared. There existed 147/310 distinct amino acid sites in the alignment, including two insertion and three deletion mutations. Distribution of antigen epitopes of two GII.8 variants was comparable, but the numbers of antigenic sites of GII.8 strains were less than that of VA387. In summary, the first GII.8 genome from China was assembled and extensively characterized, and a time-order evolutionary process of this genotype was identified with a static pattern of antigenic variations. Highlights • The first GII.8 norovirus genome sequence from China was obtained and analyzed. • GII.8 could be chronologically divided into four clusters based on the N/C region. • The numbers of antigenic sites of GII.8 strains were less than that of GII.4 VA387. • No obvious changes in epitope distribution were found between different GII.8 strains. [ABSTRACT FROM AUTHOR]

This study examines whether people smoked more under the Coronavirus Disease 2019 (COVID-19) closure policies which trapped them at home with their families. In such circumstances, the pleasure from smoking could be more tempting than usual, but at the same time smokers' families are more likely to be victims of passive smoking. This study uses temporal and regional variations in policy strengths with data from the Oxford COVID-19 Government Response Tracker project (OxCGRT) to examine the impact of COVID-19 closure policies on smoking behaviors. With longitudinal data from the China Family Panel Studies (CFPS) in 2018 and 2020, we find diminished smoking behaviors among Chinese male adults when the government implemented strict public health policies for the COVID-19 pandemic. People with more conscientiousness personality traits or stronger pro-family attitudes tend to smoke less as policy stringency increases. • This paper examines whether people smoke more under COVID-19 closure policies. • Policy stringency is the average OxCGRT score in the past 30 days before survey. • We find people smoke less when the index of policy stringency becomes higher. • Conscientious personality traits and pro-family attitudes are proxies of altruism. • The discouraging effects are stronger among people with higher family altruism. [ABSTRACT FROM AUTHOR]

We propose a novel photonic quasi-crystal fiber (PQF) with a near-zero flattened dispersion in the 1450–1650 nm optical telecommunication window. A 10-fold quasi-crystal lattice of holes is used to constitute the double clads. Using a full-vectorial finite element method, we analyze the relationship between the dispersion properties of the optical fiber and the structure parameters of cross section. According to the numerical simulation results, in 1450–1650 nm optical telecommunication window, the dispersion of the PQF can be kept within (−0.25 ± 0.31) ps/(nm km) and there are dual zero dispersion wavelengths, while the confinement loss is limited to less than 0.04 dB/km. Meanwhile, in this work it is demonstrated numerically that little variation in the fabricated affects moderately the figure of merits such as dispersion or confinement loss. Our structure and optical properties predictions are expected to provide valuable reference and basic data to aid in relative experiments and fabrication. [ABSTRACT FROM AUTHOR]

A novel Janus sponge with the ability to remove complex contaminants from water is reported. Firstly, a superhydrophilic sponge (PA@PEI-sponge) is prepared via synthesizing negatively charged phytic acid@polyethyleneimine (PA@PEI) nanoparticles and assembling them on the surface of polydopamine (PDA) and PEI-modified polyurethane (PU) sponge through electrostatic adsorption. The Janus sponge is generated by modifying one side of the PA@PEI-sponge with PDMS, which exhibits superior separation efficiency and high filtration flux toward both water-in-oil and oil-in-water emulsions due to its multiplex selective wettability and the interconnected and tortuous 3D porous channels. The numerous negatively charged active sites of PA@PEI nanoparticles and PDA layer impart the superhydrophilic PA@PEI-sponge with the removal efficiency of 39.95 ± 0.27% for malachite green (MG) via simple flow-through filtration, which can be improved to 99.92 ± 0.07% by Janus modification. More importantly, the Janus sponge exhibits an excellent treatment capacity for complex mixtures containing emulsified oil and dye, with the separation efficiency above 99.59%. The Janus sponge also demonstrates the effective separation of real industrial wastewater collected from an acrylic dyeing plant. Together with a facile and green preparation strategy, this Janus sponge shows excellent application potential for simultaneous dye removal and oil/water emulsion separation. [Display omitted] • An eco-friendly Janus sponge is prepared using a facile and green strategy. • The Janus sponge can separate both water-in-oil and oil-in-water emulsions. • The Janus modification promotes the dye removal efficiency from 39.95% to 99.92%. • The Janus sponge exhibits an excellent treatment capacity for complex wastewater. [ABSTRACT FROM AUTHOR]

A new strategy was proposed for amplifying and sequencing GII.4 norovirus genomes directly. A set of primer pairs was rationally designed, which amplified 6 overlapping fragments encompassing the whole genome. The sensitivity of new primers was comparable to that of detection primers, and 10 viral genome sequences were successfully obtained. [ABSTRACT FROM AUTHOR]

• A compact and low-cost LIF based on pinhole metal-capillary (PMC) was proposed • The background signal (noise) can be effectively suppressed in PMC • The stringent requirement on laser beam-quality can be alleviated in PMC-LIF • An overall ~480 fold improvement on SNR was realized by using PMC and laser diode • A detection limit of 0.4 pM was realized for rhodamine B detection For laser-induced fluorescence (LIF), the SNR and related concentration detectability was severely limited by background signal (noise). Herein, an axial-excitation LIF based on pinhole metal-capillary (PMC) and direct laser-diode excitation was proposed. An overall ~480 fold improvement on SNR was realized, because the laser-sidewall interaction (LSI) and related background signal (noise) can be effectively suppressed in PMC by avoidance of laser leakage and laser contact with capillary sidewall. For rhodamine B detection without sample enrichment, a detection limit of concentration (DLC) of 0.4 pM was obtained, which is 2.5 fold lower than the DLC (1 pM) of commercial LIFs equipped with bulky and expensive Ar+ laser. For selective detection of Cu2+, a DLC of 5 pM was realized, which is more than 40 fold lower than that of previous fluorimetry detection with similar quantum-dot probe. The PMC-LIF features compact (16 × 4 × 4 cm3), low-cost and high concentration detectability. [ABSTRACT FROM AUTHOR]

Background: Human norovirus is regarded as the leading cause of nonbacterial acute diarrhea in developing and developed countries. Among all genotypes, GII.4 has been the predominant genotype, but in East Asia, it was replaced by the GII.17 in 2014/2015. However, after the prevalence of new GII.17 variant in South China, a sharply increase in the number of norovirus infections associated with sporadic acute diarrhea was detected. In this study, we would investigate the prevalence and genetic diversity of noroviruses in the sporadic acute gastroenteritis cases in the post-GII.17 period in South China.Methods: Norovirus was screened from 217 patients with sporadic acute gastroenteritis from August 2015 to October 2017 by reverse transcription-polymerase chain reaction. Then, two regions including the partial RNA polymerase and the capsid gene of positive samples were amplified and sequenced. Phylogenetic analyses were performed to determine norovirus genotypes. Complete VP1 sequences of GII.4 strains detected in this study were also amplified and subjected into evolutionary tracing analyses.Results: A total of 43 (19.82%) norovirus samples were confirmed from 217 stool specimens, and it was found that GII.4 resurged as the new predominant variant, accounting for 76.74% (33/43) of positive samples. Only one local strain GZ2015-L550 was clustered with the contemporary GII.P16/GII.4-2012 recombinant variant, and other 32 local strains belonged to the clade with the GII.Pe/GII.4-2012 variant. Other genotypes including GII.17 (n = 4), GII.3 (n = 4), GII.8 (n = 1) and GI. 6 (n = 1) were also detected. Furthermore, all GII.4 strains were phylogenetic analyzed based on their capsid P2 subdomains. Combined with other reported 754 strains, the GII.4-2012 variant could be divided into two clades. Most GII.4 strains collected in 2016 and 2017 in this study (7/8) formed a new cluster A in Clade II with additional 103 contemporaneous strains. In addition, evolutionary tracing of the capsid P2 subdomain of this variant was also analyzed, and one specific amino acid substitutions (N373) was identified for Cluster A.Conclusion: In summary, this study confirmed a norovirus infection peak in the post-GII.17 period in South China, which was caused by the resurgence of the GII.4 variant. [ABSTRACT FROM AUTHOR]

Background: Human noroviruses are one of the main causes of foodborne illnesses and represent a serious public health concern. Rapid and sensitive assays for human norovirus detection are undoubtedly necessary for clinical diagnosis, especially in regions without more sophisticated equipment.Method: The rapid reverse transcription recombinase-aided amplification (RT-RAA) is a fast, robust and isothermal nucleic acid detection method based on enzyme reaction. This method can complete the sample detection at 39 °C in 30 min. In this study, we successfully established a rapid reverse transcription recombinase-aided amplification (RT-RAA) assay for the detection of human norovirus GII.4 and applied this assay to clinical samples, as well as comparison with commercial reverse transcription real-time fluorescence quantitative PCR (RT-qPCR).Results: At 95% probability, the detection sensitivity of RT-RAA was 3.425 log10 genomic copies (LGC)/reaction. Moreover, no cross-reaction was observed with other norovirus genogroups and other common foodborne viruses. Stool samples were examined by RT-RAA and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). Compared of RT-qPCR, kappa values for human norovirus detection with RT-RAA were 0.894 (p < 0.001), indicating that both assays were in agreement.Conclusion: This RT-RAA assay provides a rapid, specific, and sensitive assay for human norovirus detection and is suitable for clinical testing. [ABSTRACT FROM AUTHOR]

Noroviruses are still the primary cause of non-bacterial acute gastroenteritis worldwide. Recently, a novel GII.17 norovirus variant emerged and caused an infection peak in the cold season of 2014/2015 in some Asian countries, including China. In this study, in order to understand the evolutionary advantage of the novel variant, complete genomic sequences of GII.17 NoV strains from South China were comprehensively analyzed. Pairwise alignments of new GII.17 genomes with representative sequences of each GII genotype were performed. Inconsistent homology was observed between different protein-encoding regions, of which VPg (NS5) and P2 were found to be the most conserved and variable ones, respectively. The differences between new sequences and other reported GII.17 genomes were also compared, and 84 mismatched nucleotides were found, resulting in 15 amino acid changes. Then, all capsid sequences of different GII.17 NoV variants were collected for multiple alignments, and a total of 87 spots were identified during their evolution process. Homology modeling of capsid proteins of four GII.17 variants was carried out based on comparison with GII.4 VA387 strain, and structural differences were mainly embodied in five extended loops. Furthermore, positions of potential conformational epitope regions of new GII.17 variants were found more similar or adjacent to those of GII.4 rather than those of the former GII.17 variants. In summary, nine GII.17 strains from South China were extensively characterized based on their complete genomes, and a different distribution pattern of epitope residues was predicted on the new GII.17 variant capsid from that of the former ones. [ABSTRACT FROM AUTHOR]

The emergence of the novel GII.17 Kawasaki 2014 norovirus variant raising the interest of the public, has replaced GII.4 as the predominant cause of noroviruses outbreaks in East Asia during 2014–2015. Antigenic variation of the capsid protein is considered as one of the key mechanisms of norovirus evolution. In this study, we screened a panel of GII.17 mutants. First, we produced norovirus P proteins using cell-free protein synthesis (CFPS) system, comparing the results to pure proteins expressed in a cell-based system. Next, we determined the binding capability of specific monoclonal antibody (mAb) 2D11 using a unique set of wild-type GII.17 strains. Results of the EIA involving a panel of mutant cell-free proteins indicated that Q298 was the key residue within loop 1. These data highlighted the essential residues in the linear antibody binding characteristics of novel GII.17. Furthermore, it supported the CFPS as a promising tool for rapidly screening mutants via the scalable expression of norovirus P proteins. [ABSTRACT FROM AUTHOR]

• Axial back-and-forth-reflection (BFR) inside capillary was investigated. • A photometer based on axial -BFR inside capillary was proposed. • Optical-path enhancement of axial -BFR is more efficient than that of radial -BFR. • In comparison with radial -BFR, axial -BFR features low transmission loss. • The photometer features high sensitivity, compact, low cost and easy fabrication. As for photometry analysis, increasing the optical-path (OP) via multi-reflection is an effective method for improving the detection sensitivity. In this paper, a photometer based on axial multi-reflection between two end-faces of capillary was proposed and investigated. The probe light can be back and forth reflected inside the capillary, by employing apertured silver-mirrors at both ends of a metal-capillary. With designed aperture profile (i.e., a central disc-aperture and a peripheral ring-aperture) of the mirror, a 4.2-fold enhancement on OP was realized (i.e., OP is 4.2 times the capillary length). Moreover, the photometer was applied to detecting nitrite with a detection limit of 1 nM, which exhibits 8.6~15 fold improvement compared with that of previous photometers with similar capillary length and the same chromogenic reagent without sample enrichment. The photometer features compact, low cost and easy fabrication. [ABSTRACT FROM AUTHOR]

A reliable and high-performance oxygen (O 2) sensor based on TiO 2 -decorated bridging Gallium Nitride nanowires (TiO 2 /GaN NWs) was fabricated, which operates under ultraviolet (UV) irradiation at room temperature (RT). The TiO 2 /GaN NWs were prepared by direct-bridge growth of GaN NWs across the trench of GaN coated sapphire substrate, followed by titanium (Ti) sputtering and thermal oxidation. The morphology characteristic shows that TiO 2 nanoparticles (NPs) are anchored uniformly on the surface of GaN NWs. The sensors with various TiO 2 film thickness (0, 2, 5, 10 nm) were measured at RT under 365 nm UV illumination with O 2 concentrations varying from 1% to 25%. Experimental results show that when the TiO 2 film thickness is 5 nm, the O 2 response reaches its maximum and the limit of detection (LOD) as low as 0.45% O 2. Moreover, the 5 nm TiO 2 /GaN NWs sensor were also measured under different wavelengths (λ = 280, 365, 450 nm) UV illumination and found that the lower light wavelength, the higher O 2 sensing. In addition, the sensor has excellent repeatability, selectivity and long-term stability, thus has a wide application in the field of O 2 gas sensing. [Display omitted] • A oxygen gas sensor based on TiO 2 /GaN NWs was fabricated and well studied. • The sensor operates in air atmosphere under UV illumination (λ = 365 nm) at room temperature (∼25 ℃). • When the TiO 2 thickness is 5 nm, the O 2 response reaches its maximum and the limit of detection ∼ 0.45% O 2. • The sensor has excellent repeatability, selectivity and long-term stability. • Oxygen response under different UV wavelengths was also studied. [ABSTRACT FROM AUTHOR]

Superhydrophilic membranes with simultaneous underwater superoleophobicity are highly desirable and worth exploring for separation of emulsified oil from water. In this work, combining the strong negative charges of phytic acid (PA) and the high cationic charge density of polyethyleneimine (PEI), an eco-friendly PA@PEI polyelectrolyte complex was synthetized in aqueous solution. And then the polyelectrolyte complex was deposited onto hydrophobic PVDF membranes through a one-step assembly approach with high convenience, endowing the membranes with superhydrophilic and underwater superoleophobic property. The as-prepared PA@PEI/PVDF membrane shows outstanding static and dynamic water stability, and was successfully used to separate multiple oil-in-water emulsions, with an average rejection rate exceeding 98.5% and a water flux up to 12203.6 L m−2∙h−1∙bar−1. Furthermore, the water flux can be recovered to a high level after four separation-washing cycles, showing excellent antifouling performance and recovery capability. Together with its natural raw materials and environmentally friendly preparation strategy, the PA@PEI/PVDF membrane shows great potential in practical treatment of emulsified oily wastewater. Image 1 • An eco-friendly PA@PEI polyelectrolyte complex was synthetized using natural raw materials. • Hydrophobic PVDF membrane was transformed into superhydrophilic state by depositing the polyelectrolyte complex. • The PA@PEI/PVDF membrane could separate various oil-in-water emulsions with high water flux and satisfactory rejections. • The PA@PEI/PVDF membrane showed excellent antifouling performance and recovery capability. [ABSTRACT FROM AUTHOR]

Human noroviruses (HuNoVs) have been found as the leading cause of acute gastroenteritis outbreaks in all age groups and are significantly correlated with the consumption of shellfish. In this study, the contamination of HuNoVs in shellfish was estimated through a systematic review and meta-analysis. Studies on the contamination of HuNoVs in shellfish were searched from PubMed, Web of Science, Embase, and Cochrane Library from January 2000 to August 2021. A total of 75 studies were included, and the pooled HuNoVs prevalence in shellfish was 29% (95% CI: 23–35) worldwide. As revealed by the results of the subgroup meta-analysis, the prevalence of dominant genogroup was variable, and 4% (95% CI: 3–6), 13% (95% CI: 10–17), with 7% (95% CI: 4–11) of the samples, respectively, contaminated by GI alone, GII alone, and GI&GII. The HuNoVs prevalence of shellfish in Europe, America, and Asia was 33% (95% CI: 24–43), 24% (95% CI: 7–47), and 27% (95% CI: 18–35), respectively, while only 10% (95% CI: 5–17) in Africa. Furthermore, the prevalence of HuNoVs in shellfish was the highest in spring (35%, 95% CI: 23–49) and winter (35%, 95% CI: 22–50), and the lowest in summer (11%, 95% CI: 5–18). Oysters, clams, and mussels had comparable HuNoVs prevalence of 28% (95% CI: 20–37), 27% (95% CI: 16–39) and 24% (95% CI: 17–32), respectively. The prevalence of HuNoVs in shellfish from harvest areas and markets was 30% (95% CI: 23–38) and 30% (95% CI: 19–41), respectively. The results of this study suggest a substantial burden of HuNoVs in shellfish worldwide, with GII.4 (92.86%) and GII.2 (46.43%) as the predominant genotypes. This study provides information regarding the contamination of HuNoVs in shellfish worldwide, which will contribute to the development of appropriate control measures to prevent shellfish-related HuNoVs gastroenteritis. • The pooled prevalence of human noroviruses in shellfish was found as 29% (95% CI: 23–35) worldwide. • GII.4 (92.86%, 26/28) was found as the most common genotype in shellfish. • Significant differences were found in the seasonal and geographical prevalence of human noroviruses in shellfish. [ABSTRACT FROM AUTHOR]

Oysters and mussels are important vectors for norovirus (NoV). An efficient pretreatment method for NoV detection in oysters based on ISO 15216-2:2019 was established in our previous work, but its effectiveness for other types of shellfish remains unknown. Therefore, this study systematically compared the differences between the standard and modified ISO methods in detecting NoV for oysters and mussels. Using the standard ISO method, the recovery rates of NoV in oysters (2.10 ± 0.80 %) and mussels (2.39 ± 0.56 %) were comparable (p > 0.05, unpaired t -test). In contrast, the virus recovery rates in oysters (19.83 ± 3.64 %) and mussels (46.96 ± 3.55 %) were both significantly improved by the modified method. Also, a significant difference was found between the virus recovery rates in two shellfish (p < 0.05, unpaired t -test), resulting in a 2.09-fold difference in their virus concentrations. Additionally, the limits of detection at 95 % probability of the modified ISO method for oysters and mussels could both reach 3.33 × 103 copies/g of digestive glands. Finally, the modified ISO method has been successfully applied in commercial oysters (14/27, 51.85 %) and mussels (15/23, 65.22 %), and the results indicated a significant difference in NoV recovery rates between two shellfish (p < 0.05, one-way analysis of variance). In summary, the modified ISO method showed higher virus recovery rates than the standard ISO method, which would be used as an essential tool for NoV detection in oysters and mussels. • We developed a new method that improves viral detection in oysters and mussels. • Our method provided a higher virus recovery rate than the standard ISO method. • There were significant differences in virus recovery between oysters and mussels using the new method. [ABSTRACT FROM AUTHOR]

Norovirus diarrhea is a great threat to public health worldwide. To characterize the prevalence of circulating noroviruses associated with sporadic gastroenteritis cases in Guangzhou, 215 stool specimens were collected during two consecutive cold seasons in 2013-2015. Noroviruses were detected in 25 (11.63 %) samples, and GII.4 (6/9) and GII.17 (10/16) were identified as the most predominant variants of each of those seasons. The remaining strains belonged to the genotypes GII.P12/GII.3, GII.2, and GI.Pb/GI.6. The phylogenetic relationships of the GII.17 strains were analyzed based on their capsid protein sequences. This study suggests a significant shift of predominant variants associated with sporadic gastroenteritis in Guangzhou. [ABSTRACT FROM AUTHOR]

Noroviruses (NoVs) are the primary cause of non-bacterial acute gastroenteritis worldwide. Most NoV infections are caused by GII.4, but GII.6 is also an important genotype with a long-term persistence in human populations. In this study, the complete genome sequence of a NoV strain GZ2010-L96 isolated in China was identified and analyzed phylogenetically. The viral genome comprised 7550 nucleotides, and its phylogenetic analysis revealed that the strain belonged to GII.6 genotype. All reported GII.6 NoV capsid protein sequences were also collected for comparative analysis, and GZ2010-L96 was clustered into GII.6-b with other 8 strains. Meanwhile, it was found that 53 spots on viral capsid showed subcluster specificity according to multiple alignments. Moreover, homologous modeling of GZ2010-L96 based on comparison with GII.4 VA387 strain showed a different antigen distribution pattern. In summary, the genome of the GII.6 strain GZ2010-L96 detected in China was extensively characterized, and phylogenetic analyses of GII.6 NoVs based on the capsid proteins may reveal a different evolution process from the predominant genotype GII.4. [ABSTRACT FROM AUTHOR]

In this paper, we propose a finite-strain plate theory to study the growth-induced deformations and instabilities of multi-layered hyperelastic plates. First, under the assumption of plane-strain deformation, we formulate the governing system for a multi-layered hyperelastic (neo-Hookean) plate. The layers in the plate have different geometrical, material and growth parameters. Starting from the governing system, we propose a scheme to establish the plate equation system, where one arbitrary layer is selected as the base layer and a series-expansion approach is adopted. Through a complicated derivation procedure, the iteration relations of the unknowns in the different layers are obtained, and then the plate equation system containing the unknowns in the base layer are derived, which can attain the accuracy of O (h 2). To show the efficiency of the plate equations, we first study the growth-induced bending deformations of a multi-layered hyperelastic plate. By solving the plate equations, some analytical results are obtained, which provide accurate predictions on the deformations of the plate. The influences of the geometrical and material parameters on the response of the plate are also investigated. Besides that, the plate equation system is applied to study the growth-induced instabilities of a 3-layered hyperelastic plate. Through some conventional analyses, the critical values of the growth parameters corresponding to the different bifurcation modes are determined, which can fit the numerical results very well. In our opinion, the plate theory proposed in the current work is helpful for the design of intelligent soft devices with multi-layered plate forms. [Display omitted] • A finite-strain plate theory for growth of multi-layered hyperelastic plate is established. • The scheme for deriving the plate equations from the original governing system is proposed. • Some analytical results are obtained for growth-induced bending deformations of plates. • The instability of a 3-layered plate is studied based on the plate equations. • The obtained analytical results can fit the numerical results very well. [ABSTRACT FROM AUTHOR]

Objective. The automatic anti-cyclic citrullinated peptide (anti-CCP) antibodies assay offered great advantages over traditional methods in terms of improved precision, reliability, technical simplicity, short turnaround time and high-speed throughput. In this study, we evaluated the main technical performance and diagnostic accuracy of the first automatic anti-CCP assay approved in China. Methods. The study comprised 106 rheumatoid arthritis (RA) patients, 203 non-RA rheumatic disease controls and 46 healthy persons. Anti-CCP, rheumatoid factor (RF), α1-acid glycoprotein, C-reactive protein and erythrocyte sedimentation rate were measured and compared. The precision, reference intervals for Chinese population and cut-off value for RA diagnosis, as well as the suitable diluent for anti-CCP were assessed. The positive rate and score of anti-CCP were compared with RF and acute-phase reactants, according to the new RA criteria. Results. Within- and between-run imprecision, expressed as the coefficient of variation, were 0.47-1.36% and 1.15-2.63%, respectively. Upper 95% reference limit of anti-CCP in healthy Chinese was 8.8 U/mL. The area under curve of the receiver operating characteristic(ROC) for anti-CCP and RF were 0.882 (95% CI 0.833-0.930) and 0.844 (95% CI 0.792-0.897), respectively. Based on the cut-off value set by ROC, compared to RF, anti-CCP had higher sensitivity (96.8% vs. 78.3%) and specificity (90.9% vs. 70.7%). With 17 U/mL set as the optimal cut-off for anti-CCP, the total positivity of anti-CCP was comparable to that of RF (76.4% vs. 75.5%), but the high-positivity rate of anti-CCP was significantly higher (74.5% vs. 62.3%, p < 0.005). Conclusions. Our results confirm anti-CCP as a more sensitive and specific marker than RF for the diagnosis of RA. The diagnostic performance of the Elecsys anti-CCP assay makes it a useful adjunct to clinical practice in the Chinese population. [ABSTRACT FROM AUTHOR]

• Non-epidemic norovirus genotype GII.8 virus-like particles (VLP) were expressed using the baculovirus-insect cell system. • Binding of GII.8 VLP to tissue blood group antigens (HBGAs) was observed. • The cross-reactivity of GII.8 VLP antiserum with other 27 (9 GI genotypes and 18 GII genotypes) capsid protein was evaluated. • Norovirus GII.8 strain antiserum had no cross-blocking effect on the binding of epidemic genotypes (GII.4, GII.17) to HBGA. • The existing vaccine candidate strain GI.1 antiserum and GII.4 antiserum had no cross-blocking effect on the binding of NoV GII.8 to HBGA. Noroviruses are causative agents of acute nonbacterial gastroenteritis epidemics worldwide. There are various genotypes, among which the non-epidemic genotype GII.8 can cause norovirus outbreaks. We previously demonstrated that the immunogenicity of GII.8 differed from that of epidemic variants. This study aimed to comprehensively compare the receptor profile and immunogenicity of the GII.8 variant with those of the epidemic variants. Using the baculovirus-insect cell expression system, we observed that recombinant capsid protein VP1 of the norovirus GII.8 GZ2017-L601 strain formed virus-like particles (VLPs) with a diameter of approximately 30 nm, as evidenced by transmission electron microscopy analysis. The GII.8 VLPs showed weak or moderate binding with all secretor histo-blood group antigens (HBGAs), but not with non-secretors, as evidenced by the HBGA-VLP binding test. The GII.8 VLP antiserum obtained from immunized BALB/c mice was tested for cross-reactivity with other norovirus genotypes (n = 28). The results showed that this antiserum demonstrated moderate cross-reactivity with GI.1, GII.3, and GII.15; however, no cross-reactivity with the epidemic variants of GII.2, GII.4, and GII.17 was observed. Additionally, the blocking-antibody activity of GII.8 antisera against GII.4 VLP-HBGAs and GII.17 VLP-HBGAs interactions and the cross-blocking of GII.8 VLP-HBGAs interactions by GI.1 and GII.4 antisera were evaluated using the HBGAs-VLP blocking test. However, no cross-blocking effect was observed. In summary, the characterization of norovirus GII.8 VLPs and derived antisera revealed that the GII.8 immunogenicity differed from that of epidemic variants. [ABSTRACT FROM AUTHOR]

[Display omitted] • A digital isothermal detection chip was established for norovirus detection. • The first proposal of digital RAA. • Absolute quantification achieved at a linear range of 1.02 × 10–2.04 × 103 copies/μL. • The new method time is only 20 min. • The new method has been successfully applied in clinical testing. As the rapid spread of norovirus is a major public health problem, rapid diagnostic assays are essential in assisting the implementation of appropriate control measures. Here, we presented a facile sample partitioning norovirus digital isothermal detection (NoV-DID) chip that enables the application of a fast and low-cost digital nucleic acid amplification test (dNAAT) to norovirus detection. Our microfluidic chip had 3 layers, a PDMS cover layer, a functional layer, and a supporting layer, and consisted of a total of 5120 microchambers, each of which was able to contain a volume of 1.2 nL. This chamber digital reverse transcription recombinase-aid amplification (cdRT-RAA) assay achieved equal volume partition of samples within 10 min, with the signal amplification being completed in approximately 20 min at 39 °C, without the need for a thermal cycle device. The cdRT-RAA assay showed a good degree of linearity in the range of 1.02 × 100 to 2.04 × 103 copies (R2 = 0.99) with the limit of detection being 1.02 × 100 copies/μL, demonstrating that its sensitivity was comparable to that of RT-ddPCR. The digital nucleic acid detection method based on the microfluidic chip exhibited advantages of high sensitivity and high robustness, and might provide an alternative method for the early detection of norovirus and the prevention and control of epidemics. [ABSTRACT FROM AUTHOR]

Noroviruses are the primary cause of gastroenteritis and foodborne diseases, affecting millions of individuals annually worldwide. Oysters are frequently associated with norovirus outbreaks. Hence, inexpensive and simple norovirus detection methods are important to detect and contain foodborne illness outbreaks. The objective of this study is to develop a high-efficient concentrated pretreatment method for reverse transcriptase quantitative real-time polymerase chain reaction (RT-qPCR) detection. Based on the existing ISO/TS 15216-2:2013 standard (ISO/TS 15216-2., 2013), four methods are compared for recovery of norovirus from spiked digestive tissue of oysters. A method is found to be the most efficient based on protease K method of increasing buffer volume and PEG precipitation method. The recovery rate and amplification efficiency approached 11.07 ± 0.09% and 124.12 ± 5.99%, respectively, being 7-fold that of the original ISO/TS 15216-2:2013 method. This method serves as a rapid (1.5h) sample concentration tool with a limit of detection as low as 7.05 × 103 copies. Thirty-eight oyster samples from an aquatic products market in Guangzhou are tested using this method, and noroviruses are detected in 13 samples. This method is an effective extension of the existing ISO/TS 15216-2:2013 standard and it is potentially applicable for detecting norovirus contamination in oysters. • PEG precipitation with proteinase K treatment was performed to detect NoV in independent oysters. • This method had a higher recovery rate than the standard ISO/TS 15216-2:2013 method. • This method had a better amplification efficiency upon RT-qPCR-based monitoring. [ABSTRACT FROM AUTHOR]