40 research outputs found

    Evaluating the importation of yellow fever cases into China in 2016 and strategies used to prevent and control the spread of the disease

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    During the yellow fever epidemic in Angola in 2016, cases of yellow fever were reported in China for the first time. The 11 cases, all Chinese nationals returning from Angola, were identified in March and April 2016, one to two weeks after the peak of the Angolan epidemic. One patient died; the other 10 cases recovered after treatment. This paper reviews the epidemiological characteristics of the 11 yellow fever cases imported into China. It examines case detection and disease control and surveillance, and presents recommendations for further action to prevent additional importation of yellow fever into China

    Secretion of Genome-Free Hepatitis B Virus – Single Strand Blocking Model for Virion Morphogenesis of Para-retrovirus

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    As a para-retrovirus, hepatitis B virus (HBV) is an enveloped virus with a double-stranded (DS) DNA genome that is replicated by reverse transcription of an RNA intermediate, the pregenomic RNA or pgRNA. HBV assembly begins with the formation of an “immature” nucleocapsid (NC) incorporating pgRNA, which is converted via reverse transcription within the maturing NC to the DS DNA genome. Only the mature, DS DNA-containing NCs are enveloped and secreted as virions whereas immature NCs containing RNA or single-stranded (SS) DNA are not enveloped. The current model for selective virion morphogenesis postulates that accumulation of DS DNA within the NC induces a “maturation signal” that, in turn, triggers its envelopment and secretion. However, we have found, by careful quantification of viral DNA and NCs in HBV virions secreted in vitro and in vivo, that the vast majority of HBV virions (over 90%) contained no DNA at all, indicating that NCs with no genome were enveloped and secreted as empty virions (i.e., enveloped NCs with no DNA). Furthermore, viral mutants bearing mutations precluding any DNA synthesis secreted exclusively empty virions. Thus, viral DNA synthesis is not required for HBV virion morphogenesis. On the other hand, NCs containing RNA or SS DNA were excluded from virion formation. The secretion of DS DNA-containing as well as empty virions on one hand, and the lack of secretion of virions containing single-stranded (SS) DNA or RNA on the other, prompted us to propose an alternative, “Single Strand Blocking” model to explain selective HBV morphogenesis whereby SS nucleic acid within the NC negatively regulates NC envelopment, which is relieved upon second strand DNA synthesis

    Hippo signalling governs cytosolic nucleic acid sensing through YAP/TAZ-mediated TBK1 blockade

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    The Hippo pathway senses cellular conditions and regulates YAP/TAZ to control cellular and tissue homeostasis, while TBK1 is central for cytosolic nucleic acid sensing and antiviral defence. The correlation between cellular nutrient/physical status and host antiviral defence is interesting but not well understood. Here we find that YAP/TAZ act as natural inhibitors of TBK1 and are vital for antiviral physiology. Independent of transcriptional regulation and through the transactivation domain, YAP/TAZ associate directly with TBK1 and abolish virus-induced TBK1 activation, by preventing TBK1 Lys63-linked ubiquitylation and the binding of adaptors/substrates. Accordingly, YAP/TAZ deletion/depletion or cellular conditions inactivating YAP/TAZ through Lats1/2 kinases relieve TBK1 suppression and boost antiviral responses, whereas expression of the transcriptionally inactive YAP dampens cytosolic RNA/DNA sensing and weakens the antiviral defence in cells and zebrafish. Thus, we describe a function of YAP/TAZ and the Hippo pathway in innate immunity, by linking cellular nutrient/physical status to antiviral host defence

    FTIR Study of White and Green Broad Beans Based on Curve-fitting

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    Fourier transform infrared (FTIR) spectroscopy was used to study two kinds of broad beans with white and green cotyledons respectively. The results show that the infrared spectra of the two kinds of broad beans are similar and mainly made up of the absorption bands of protein, and polysaccharides. The second derivative infrared spectra amplified the differences and revealed that there were some obvious differences in the range of 1 800-700cm-1 and 1 200-700cm-1. Hierarchical cluster analysis (HCA) were used for the discrimination of the two kinds broad beans based on the second derivative spectral data in the region of 1 611-1 100cm-1, and yielded 88.9 % accuracy. The spectra in the range from 1700 to 1600cm-1 were used to perform Fourier self-deconvolution and curve fitting, which obtained nine peaks. The ratios of relative areas of the bands at α-helix, β-sheet, β-turn and the unordered structure of protein in white beans were 67.71%, 35.6%, 35.6% and 21.09% respectively, while the ratios in green beans were 8.02%, 31.59%, 37.12% and 23.27% respectively. The results indicate that the secondary structure of protein was different in the two kinds of broad beans

    Ganoderma lucidum polysaccharide improves rat DSS-induced colitis by altering cecal microbiota and gene expression of colonic epithelial cells

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    Background: The effects of β-glucan on colitis mice are contradictory in previous reports. As a result, it is still unclear whether there is an anti-colitis effect in Ganoderma lucidum polysaccharide (GLP), which is mainly composed of β-glucan. Moreover, the association between GLP function and gut microbiota remains to be elucidated. Objective: This study aimed to investigate whether GLP consumption improved rat dextran sodium sulfate (DSS)-induced colitis by regulating gut microbiota and altering colonic epithelial expression. Design: The disease activity index (DAI) scores and the cecal short chain fatty acid (SCFA) levels of DSS-induced colitis rats fed with a GLP diet (Group GLP, n = 6) and a control diet (Group Con, n = 6) were investigated and analyzed. Moreover, the profiles of gut microbiota and colonic epithelial expression were analyzed using metagenomics and transcriptomics. Results: GLP consumption significantly lowered animal DAI scores by producing more SCFAs by increasing SCFA-producing bacteria such as Ruminococcus_1 and reducing pathogens such as Escherichia-Shigella in both the small intestine and cecum of rat. Moreover, GLP consumption regulated 11 genes, including six upregulated (Ccl5, Cd3e, Cd8a, Il21r, Lck, and Trbv) and five downregulated (Ccl3, Gro, Il11, Mhc2, and Ptgs) genes enriched in six inflammation-related Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, resulting in enhancement of immunity and reduction of inflammatory response and colonic cancer risk. Conclusions: GLP consumption alleviated DSS-induced colitis and may have potential for ulcerative colitis relief

    Biosorption of Silver Ions by Biomass: Equilibrium, Kinetics and Thermodynamics

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    The freeze-dried biomass of Paecilomyces lilacinus was employed as a biosorbent for the removal of silver ions from aqueous solution. The effects of factors such as the solution pH, the initial Ag(I) ion concentration, contact time and temperature were examined. Maximum Ag(I) adsorption was obtained at pH 3.0. The pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetic models were fitted to the experimental data when it was found that such data were best fitted by the pseudo-second-order kinetic model. The equilibrium experimental data were well fitted by the Langmuir model (R 2 > 0.995) and the maximum biosorption capacity at 298 K was 101.0 mmol/g. Thermodynamic parameters such as the Gibbs' free energy, ΔG 0 , the standard enthalpy, ΔH 0 , and the standard entropy, ΔS 0 , were evaluated. The results indicated that the biosorption of Ag(I) ions onto P. lilacinus biomass was spontaneous and endothermic in nature. The FT-IR analysis results indicated that amine, carboxylic and hydroxyl groups were involved in the biosorption process

    Adaptive runge-kutta discontinuous galerkin method for complex geometry problems on cartesian grid

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    A Cartesian grid method using immersed boundary technique to simulate the impact of body in fluid has become an important research topic in computational fluid dynamics because of its simplification, automation of grid generation, and accuracy of results. In the frame of Cartesian grid, one often uses finite volume method with second order accuracy or finite difference method. In this paper, an h-adaptive Runge–Kutta discontinuous Galerkin (RKDG) method on Cartesian grid with ghost cell immersed boundary method for arbitrarily complex geometries is developed. A ghost cell immersed boundary treatment with the modification of normal velocity is presented. Themethod is validated versus well documented test problems involving both steady and unsteady compressible flows through complex bodies over a wide range of Mach numbers. The numerical results show that the present boundary treatment to some extent reduces the error of entropy and demonstrate the efficiency, robustness, and versatility of the proposed approach

    Alternating consumption of β‐glucan and quercetin reduces mortality in mice with colorectal cancer

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    The current dietary recommendations for disease prevention and management are scarce and are not well supported. Beta‐glucan or quercetin in a diet can alleviate colorectal cancer (CRC) by regulating the gut microbiota and related genes, but the effects of alternating their consumption for routine ingestion during CRC occurrence remain unknown. This study investigated the effects of alternating the consumption of β‐glucan and quercetin for routine ingestion on CRC development in mice. The mortality rate, colonic length, inflammatory cytokines, gut microbiota, and colonic epithelial gene expression in healthy and CRC mice that consumed normal and alternate diets were compared and studied. The results showed that alternating the consumption of β‐glucan and quercetin (alternating among a β‐glucan diet, a normal diet and a normal diet that was supplemented with quercetin) alleviated colon damage and reduced the mortality rate in CRC mice, with a reduction in mortality of 12.5%. Alternating the consumption of β‐glucan and quercetin significantly decreased the TNF‐α level, increased the relative abundance of Parabacteroides, and downregulated three genes (Hmgcs2, Fabp2, and Gpt) that are associated with inflammation and cancer. Alternating the consumption of some bioactive compounds, such as β‐glucan and quercetin, in food can contribute to human health. This experiment provided some experimental evidence for the dietary recommendations for disease prevention and management

    Alternating consumption of β‐glucan and quercetin reduces mortality in mice with colorectal cancer

    No full text
    The current dietary recommendations for disease prevention and management are scarce and are not well supported. Beta‐glucan or quercetin in a diet can alleviate colorectal cancer (CRC) by regulating the gut microbiota and related genes, but the effects of alternating their consumption for routine ingestion during CRC occurrence remain unknown. This study investigated the effects of alternating the consumption of β‐glucan and quercetin for routine ingestion on CRC development in mice. The mortality rate, colonic length, inflammatory cytokines, gut microbiota, and colonic epithelial gene expression in healthy and CRC mice that consumed normal and alternate diets were compared and studied. The results showed that alternating the consumption of β‐glucan and quercetin (alternating among a β‐glucan diet, a normal diet and a normal diet that was supplemented with quercetin) alleviated colon damage and reduced the mortality rate in CRC mice, with a reduction in mortality of 12.5%. Alternating the consumption of β‐glucan and quercetin significantly decreased the TNF‐α level, increased the relative abundance of Parabacteroides, and downregulated three genes (Hmgcs2, Fabp2, and Gpt) that are associated with inflammation and cancer. Alternating the consumption of some bioactive compounds, such as β‐glucan and quercetin, in food can contribute to human health. This experiment provided some experimental evidence for the dietary recommendations for disease prevention and management

    A new immersed boundary method for compressible Navier-Stokes equations

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    De Montfort University, UK; National Science Foundation of China [11102179]; Science Foundation of Institutions of Higher Education of Jiangsu Province, China [11KJB110016]This paper presents an immersed boundary method for compressible Navier-Stokes equations in irregular domains, based on a local radial basis function approximation. This approach allows one to define a reconstruction of the radial basis functions on each irregular interface cell to treat both the Dirichlet and Neumann boundary conditions accurately on the immersed interfaces. Several numerical examples, including problems with available analytical solutions and the well-documented flow past an airfoil, are presented to test the proposed method. The numerical results demonstrate that the proposed method provides accurate solutions for viscous compressible flows
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