Epidemiological and genetic characteristics of norovirus in Hangzhou, China, in the postepidemic era.

OBJECTIVE: Norovirus (NoV) is an important human pathogen that can cause severe gastroenteritis in vulnerable populations. This study aimed to analyze the epidemiological and genetic characteristics of 2021-2023 NoV in Hangzhou, China. METHODS: This study enrolled patients aged 0-18 years who underwent NoV RNA detection in the hospital between January 2021 and October 2023 and analyzed the epidemiological characteristics of NoV. Polymerase chain reaction (PCR) was used to detect NoV RNA. Subtype classification and whole-genome sequencing were performed. RESULTS: There was a high prevalence of NoV infection in 2023, with NoV-positive samples accounting for 63.10 % of the total number of positive samples collected during the three-year period. The prevalence was abnormally high in summer, and the number of positive samples accounted for 48.20 % of the total positive samples for the whole year, which was much greater than the level in the same period in previous years (2023, 48.20% vs 2021, 13.66% vs 2022, 15.21 %). The GⅡ.4 subtype played a leading role, followed by increased mixed infection with GⅠ.5 and GⅡ.4. Whole-genome sequencing results suggested that GII.P16-GⅡ.4 had R297H and D372N key locus mutations. The evolutionary rate was 4.29 × 10-3 for the RdRp gene and 4.84 × 10-3 for the VP1 gene. The RdRp gene and VP1 gene of NoV GII.P16-GⅡ.4 have undergone rapid population evolution during the COVID-19 epidemic. CONCLUSION: In the summer of 2023, an abnormally high incidence of NoV appeared in Hangzhou, China. The major epidemic strain GII.P16-GⅡ.4 showed a certain range of gene mutations and a fast evolutionary rate.

The effect of nonpharmaceutical interventions on influenza virus transmission.

Background: The use of nonpharmaceutical interventions (NPIs) during severe acute respiratory syndrome 2019 (COVID-19) outbreaks may influence the spread of influenza viruses. This study aimed to evaluate the impact of NPIs against SARS-CoV-2 on the epidemiological features of the influenza season in China. Methods: We conducted a retrospective observational study analyzing influenza monitoring data obtained from the China National Influenza Center between 2011 and 2023. We compared the changes in influenza-positive patients in the pre-COVID-19 epidemic, during the COVID-19 epidemic, and post-COVID-19 epidemic phases to evaluate the effect of NPIs on influenza virus transmission. Results: NPIs targeting COVID-19 significantly suppressed influenza activity in China from 2019 to 2022. In the seventh week after the implementation of the NPIs, the number of influenza-positive patients decreased by 97.46% in southern regions of China and 90.31% in northern regions of China. However, the lifting of these policies in December 2022 led to an unprecedented surge in influenza-positive cases in autumn and winter from 2022 to 2023. The percentage of positive influenza cases increased by 206.41% (p < 0.001), with high positivity rates reported in both the northern and southern regions of China. Conclusion: Our findings suggest that NPIs against SARS-CoV-2 are effective at controlling influenza epidemics but may compromise individuals' immunity to the virus.

Single walled carbon nanotubes band gap width measurement and the influence of nitrogen doping research.

The adjustment and measurement of the band gap width of single-walled carbon nanotubes are crucial for optimizing the design and enhancing the performance of carbon-based devices. This study utilizes the relationship between the band gap and temperature of semiconductor-based carbon nanotubes. The electrical conductivity of carbon nanotubes was obtained at various temperatures, and the corresponding band gap width (0.57 eV) was determined. The introduction of nitrogen results in a reduction of the band gap width and an increase in current flow between the device source and drain electrodes. Theoretical calculation demonstrated that nitrogen doping not only increases the conductivity of carbon nanotubes but also effectively inhibits the Schottky barrier between carbon nanotubes and metal electrodes. The Schottky barrier and the internal electric field can be effectively modulated via nitrogen doping in carbon nanotubes, which enhances the performance of carbon-based devices.

Functional analysis of a down-regulated transcription factor-SoxNeuroA gene involved in the acaricidal mechanism of scopoletin against spider mites.

BACKGROUND: Insight into the mode of action of plant-derived acaricides will help in the development of sustainable control strategies for mite pests. Scopoletin, a promising plant-derived bioactive compound, displays prominent acaricidal activity against Tetranychus cinnabarinus. The transcription factor SoxNeuroA plays a vital role in maintaining calcium ion (Ca2+ ) homeostasis. Down-regulation of SoxNeuroA gene expression occurs in scopoletin-exposed mites, but the functional role of this gene remains unknown. RESULTS: A SoxNeuroA gene from T. cinnabarinus (TcSoxNeuroA) was first cloned and identified. Reverse transcription polymerase chain reaction (RT-PCR), quantitative real-time polymerase chain reaction (qPCR), and Western blotting assays all confirmed that the gene expression and protein levels of TcSoxNeuroA were significantly reduced under scopoletin exposure. Furthermore, RNA interference silencing of the weakly expressed SoxNeuroA gene significantly enhanced the susceptibility of mites to scopoletin, suggesting that the acaricidal mechanism of scopoletin was mediated by the weakly expressed SoxNeuroA gene. Additionally, yeast one-hybrid (Y1H) and dual-luciferase reporter assays revealed that TcSoxNeuroA was a repressor of Orai1 Ca2+ channel gene transcription, and the key binding sequence was ATCAAAG (positions -361 to -368 of the Orai1 promoter). Importantly, site-directed mutagenesis and microscale thermophoresis assays further indicated that ASP185, ARG189, and LYS217, which were key predicted hydrogen-bonding sites in the molecular docking model, may be the vital binding sites for scopoletin in TcSoxNeuroA. CONCLUSION: These results demonstrate that the acaricidal mechanism of scopoletin involves inhibition of the transcription factor SoxNeuroA, thus inducing the activation of the Orai1 Ca2+ channel, eventually leading to Ca2+ overload and lethality. Elucidation of the transcription factor-targeted mechanism for this potent plant-derived acaricide has vital implications for the design of next-generation green acaricides with novel targets. © 2023 Society of Chemical Industry.

Escherichia coli Infection Sepsis: An Analysis of Specifically Expressed Genes and Clinical Indicators.

Since E. coli is the most prevalent sepsis bacterium, studying its pathogenic molecular pathways may help with its early diagnosis and individualized treatment. However, few studies have investigated the molecular characterization of E. coli infection only. We extracted E. coli infection-specific genes and indicators from published data and clinical laboratory results in this study. GSE65088 showed 277, 377, and 408 DEGs for E. coli and other bacteria, E. coli and healthy groups, and other bacteria and healthy groups, respectively. DEGs, the MEgreen module with the highest relevance in WGCNA, and the first three MCODE subnetworks were used to find E. coli infection-specific hub genes. HSPA1B and TNF were verified in GSE6269 with ROC-AUCs of 0.7038 and 0.7116, respectively. CIBERSORT showed increased B-cell naive and T-cell CD4 naive infiltration in E. coli infectious sepsis. Patients infected with E. coli were younger than those infected with other pathogens. Compared to the other bacterially infectious sepsis patients, the E. coli patients had low globulin, prealbumin, creatine kinase, and high bilirubin levels. The clinically significant difference indicator IL-2, in combination with hub genes, better differentiated the healthy and E. coli groups, with an ROC-AUC of 0.8793. The study suggested that HSPA1B and TNF may be E.-coli-infection-specific genes, which may help explain the molecular mechanism of infectious sepsis.

Theoretical and experimental investigations of enhanced carbon nanotube-gold interface conductivity through nitrogen doping.

It is necessary to establish high-quality contact between carbon nanotubes and metals in carbon-based devices. However, how to control and reduce contact resistance still remains unsolved. In this study, the effect of N doping in single-walled carbon nanotubes on the contact resistance with gold was studied by combining theoretical calculation with experimental methods. The theoretical results indicate that nitrogen doping in carbon nanotubes can control the bottom of the carbon nanotube conduction band downward, the Fermi level enters the conduction band, the height of the Schottky barrier between the bottom of the carbon nanotube conduction band and the gold Fermi level decreases, and the increase in doping concentration leads to the decrease of Schottky barrier width. As a result, the conductivity between the gold and carbon nanotube interface is enhanced. During experiments, the carrier density and the current of the gold and carbon nanotube device increase gradually with the increase in N doping concentration and a good electron transport channel is established between the gold and carbon nanotubes. The high-quality contact is crucial to reducing the size, improving the performance, and reducing the power consumption of carbon-based devices.

Development of Sustainable Insecticide Candidates for Protecting Pollinators: Insight into the Bioactivities, Selective Mechanism of Action and QSAR of Natural Coumarin Derivatives against Aphids.

Plants employ abundant toxic secondary metabolites to withstand insect attack, while pollinators can tolerate some natural defensive compounds. Coumarins, as promising green alternatives to chemical insecticides, possess wide application prospects in the crop protection field. Herein, the bioactivities of 30 natural coumarin derivatives against Aphis gossypii were assessed and revealed that 6-methylcoumarin exhibited potent aphicidal activity against aphids but displayed no toxicity to honeybees. Additionally, using biochemical, bioinformatic, and molecular assays, we confirmed that the action mode of 6-methylcoumarin against aphids was by inhibiting acetylcholinesterase (AChE). Meanwhile, functional assays revealed that the difference in action site, which located in Lys585 in aphid AChE (equivalent to Val548 in honeybee AChE), was the principal reason for 6-methylcoumarin being toxic to aphids but safe to pollinators. This action site was further validated by mutagenesis data, which uncovered how 6-methylcoumarin was unique selective to the aphid over honeybee or mammalian AChE. Furthermore, a 2D-QSAR model was established, revealing that the central structural feature was H3m, which offers guidance for the future design of more potent coumarin compounds. This work provides a sustainable strategy to take advantage of coumarin analogues for pest management while protecting nontarget pollinators.

The role of microbial interactions in dental caries: Dental plaque microbiota analysis.

OBJECTIVES: Dental caries is a result of the ecological dysfunction of the polymicrobial community on the tooth surface, which evolves through microbial interactions. In this study, we conducted a thorough analysis of the dental plaque microbiome to comprehend its multi-microbial aetiology. MATERIALS AND METHOD: In this study, plaque was collected from healthy tooth surfaces, shallow carious teeth and deep carious teeth, and bacterial composition and abundance were assessed using 16S rRNA high-throughput sequencing. Random forest and LEfSe were used to profile various microorganisms at each stage. Additionally, we developed a molecular ecological network (MEN) based on random matrix theory (RMT) to examine microbial interactions for the first time. RESULTS: Our results reveal that Scardovia wiggsiae, Streptococcus mutans, and Propionibacterium acidifaciens may be associated with initial caries, and Propionibacterium acidifaciens differentiates between shallow and deep caries. As caries progressed, the alpha diversity index declined, indicating a decrease in microbial variety. The network topological indices such as centralization betweenness revealed that the caries network had become more complex, involving more microbial interactions. The shallow network revealed a high negative correlation ratio across nodes, indicating that microbes competed heavily. In contrast, the positive correlation ratio of deep network nodes was high, and microorganisms transitioned from a competitive to a synergistic state. CONCLUSIONS: This study suggests that microbial diversity and interactions are critical to caries progression and that future caries research should give greater consideration to the role of microbial interaction factors in caries progression.

Immunogenicity and Blocking Efficacy of Norovirus GII.4 Recombinant P Protein Vaccine.

Noroviruses (NoVs) are the main cause of acute gastroenteritis in all ages worldwide. The aim of this study was to produce the recombinant P protein of norovirus and to demonstrate its blocking effect. In this study, the engineered strains were induced to express the P protein of NoVs GII.4, which was identified using SDS-PAGE and ELISA as having the capacity to bind to histo-blood group antigens (HBGAs). Rabbits were immunized to obtain neutralizing antibodies. ELISA and ISC-RT-qPCR were used to determine the blocking efficacy of the neutralizing antibody to human norovirus (HuNoV) and murine norovirus (MNV). The recombinant P protein (35 KD) was obtained, and the neutralizing antibody was successfully prepared. The neutralizing antibody could block the binding of the P protein and HuNoV to HBGAs. Neutralizing antibodies can also block MNV invasion into host cells RAW264.7. The recombinant P protein expressed in E. coli can induce antibodies to block HuNoV and MNV. The recombinant P protein of NoVs GII.4 has the value of vaccine development.

Tiny nano-scale junction built on B/N doped single carbon nanotube.

The characteristic sizes of carbon nanotube (CNT)-based devices are constantly being reduced. However, this continuing miniaturization is still facing many problems and requires innovative ideas and structures. By regular doping of boron and nitrogen atoms in a semiconducting single-wall carbon nanotube (SWCNT), we have constructed a nano-scale junction with rectifying characteristics. The I-V curve of our junction resembles the I-V curve of an ideal diode with a p-n junction. This junction channel is about 0.6 nm wide and 3.4 nm long, and the footprint is 5.1 nm long. Under a 0.5 V bias, the junction has a leakage current of -8.8 × 10-3 µA, a rectifying ratio Ion/Ioff of 0.716 × 103, and a current density of 10.52 mA µm-1. Our study also shows how different dopant distributions influence the I-V curve. Such a regular nano-scale doping method is effective and important, compared with the traditional random doping method.

A Cu-atom-chain current channel with a width of approximately 0.246 nm on (5, 0) single-wall carbon nanotube.

Continuous miniaturization with improved performance has enabled the development of electronic devices. However, further shrinking of electronic circuits will push feature sizes (linewidths) firmly into the nanoscale. This can cause electronic devices built using current materials (silicon-based) and fabrication processes to not work as expected. Therefore, new materials or preparation technologies are needed for the further miniaturization of electron devices. Here, through theoretical simulation, we show that regular doping of a Cu-atom chain on a single-wall carbon nanotube (SWCNT) can be used to realize an atomic-scale current channel (Cu-atom-chain current channel) with a linewidth of approximately 0.246 nm. Moreover, the atomic-scale Cu-atom-chain current channel shows enhanced conductivity (lower power consumption) compared to a pristine SWCNT. Such a Cu-atom-chain current channel with an atomic-scale linewidth and its method of fabrication (regular doping) may be suitable for the preparation of nanoelectronic devices.

The structure, stability, and electronic properties of ultra-thin BC2N nanotubes: a first-principles study.

Rapid developments of the silicon electronics industry have close to the physical limits and nanotube materials are the ideal materials to replace silicon for the preparation of next generation electronic devices. Boron-carbon-nitrogen nanotubes (BCNNT) can be formed by joining carbon nanotube (CNT) and boron nitride nanotube (BNNT) segments, and BC2N nanotubes have been widely and deeply studied. Here, we employed first-principles calculations based on density function theory (DFT) to study the structure, stability, and electronic properties of ultra thin (4 Å diameter) BC2N nanotubes. Our results showed that the cross sections of BC2N nanotubes can transform from round to oval when CNT and BNNT segments are parallel to the tube axis. It results when the curvature of BNNT segments become larger than CNT segments. Further, we found the stability of BC2N nanotubes is sensitive to the number of B-N bonds, and the phase segregation of BNNT and CNT segments is energetically favored. We also obtained that all (3,3) BC2N nanotubes are semiconductor, whereas (5,0) BC2N nanotubes are conductor when CNT and BNNT segments are perpendicular to the tube axis; and semiconductor when CNT and BNNT segments are parallel to the tube axis. These electronic properties are abnormal when compared to the relative big ones.

Tunable electronic properties of ultra-thin boron-carbon-nitrogen heteronanotubes for various compositions.

A first-principles calculation was carried out to investigate the stability and electronic properties of ultra-thin Cx(BN)y heteronanotubes which were composed by joining pure CNT and BNNT segments with different composition and configurations. We found that the stability of Cx(BN)y heteronanotubes is increased with the increasing number of B and N atoms. In addition, all armchair (3,3) Cx|(BN)y heteronanotubes were found to be semiconductors with tunable energy gaps between 0.45 to 1.62 eV. Whereas zigzag (5,0) Cx|(BN)y heteronanotubes can be metal (y≤4) or semiconductor (y>4), and it is different from the relatively big zigzag Cx|(BN)y heteronanotubes which are always conductors. It indicates that the energy gap of (5,0) Cx|(BN)y heteronanotubes can be tuned by modifying the value of y. Further, zigzag (5,0) and armchair (3,3) C-BN heteronanotubes were found to be metal and semiconductor, respectively; but zigzag and armchair C-BN heteronanotubes with relatively big diameter are always semiconductor and conductor, respectively. Therefore, the electronic properties of ultra-thin Cx(BN)y heteronanotubes are abnormal when comparing with the relatively big ones. Highlights• The stability of Cx(BN)y heteronanotubes is increased with the increasing value of y.• Zigzag (5,0) Cx|(BN)y heteronanotubes can change from metal (y≤4) to semiconductor (y>4) when the value of y increases from 1 to 7.• The band gaps of armchair (3,3) Cx|(BN)y heteronanotubes increase from 0.45 to 1.62 eV when the value of y increases from 1 to 7.• The electronic properties (energy gap) of Cx(BN)y heteronanotubes are tunable and different in comparison with the relatively big ones.