4,287 research outputs found

    Quantifying mechanistic traits of influenza viral dynamics using in vitro data.

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    When analysing in vitro data, growth kinetics of influenza virus strains are often compared by computing their growth rates, which are sometimes used as proxies for fitness. However, analogous to mathematical models for epidemics, the growth rate can be defined as a function of mechanistic traits: the basic reproduction number (the average number of cells each infected cell infects) and the mean generation time (the average length of a replication cycle). Fitting a model to previously published and newly generated data from experiments in human lung cells, we compared estimates of growth rate, reproduction number and generation time for six influenza A strains. Of four strains in previously published data, A/Canada/RV733/2003 (seasonal H1N1) had the lowest basic reproduction number, followed by A/Mexico/INDRE4487/2009 (pandemic H1N1), then A/Indonesia/05/2005 (spill-over H5N1) and A/Anhui/1/2013 (spill-over H7N9). This ordering of strains was preserved for both generation time and growth rate, suggesting a positive biological correlation between these quantities which have not been previously observed. We further investigated these potential correlations using data from reassortant viruses with different internal proteins (from A/England/195/2009 (pandemic H1N1) and A/Turkey/05/2005 (H5N1)), and the same surface proteins (from A/Puerto Rico/8/34 (lab-adapted H1N1)). Similar correlations between traits were observed for these viruses, confirming our initial findings and suggesting that these patterns were related to the degree of human adaptation of internal genes. Also, the model predicted that strains with a smaller basic reproduction number, shorter generation time and slower growth rate underwent more replication cycles by the time of peak viral load, potentially accumulating mutations more quickly. These results illustrate the utility of mathematical models in inferring traits driving observed differences in in vitro growth of influenza strains

    Pan-African metamorphic and magmatic rocks of the Khanka Massif, NE China: Further evidence regarding their affinity

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    The Khanka Massif is a crustal block located along the eastern margin of the Central Asian Orogenic Belt (CAOB) and bordered to the east by Late Jurassic-Early Cretaceous circum-Pacific accretionary complexes of the Eastern Asian continental margin. It consists of graphite-, sillimanite- and cordierite-bearing gneisses, carbonates and felsic paragneisses, in association with various orthogneisses. Metamorphic zircons from a sillimanite gneiss from the Hutou complex yield a weighted mean 206Pb/ 238U age of 490 ± 4 Ma, whereas detrital zircons from the same sample give ages from 934-610 Ma. Magmatic zircon cores in two garnet-bearing granite gneiss samples, also collected from the Hutou complex, yield weighted mean 206Pb/ 238U ages of 522 ± 5 Ma and 515 ± 8 Ma, whereas their metamorphic rims record 206Pb/ 238U ages of 510-500 Ma. These data indicate that the Hutou complex in the Khanka Massif records early Palaeozoic magmatic and metamorphic events, identical in age to those in the Mashan Complex of the Jiamusi Massif to the west. The older zircon populations in the sillimanite gneiss indicate derivation from Neoproterozoic sources, as do similar rocks in the Jiamusi Massif. These data confirm that the Khanka Massif has a close affinity with other major components of the CAOB to the west of the Dun-Mi Fault. Based on these results and previously published data, the Khanka Massif is therefore confirmed as having formed a single crustal entity with the Jiamusi (and possibly the Bureya) massif since Neoproterozoic time. Copyright © Cambridge University Press 2010.published_or_final_versio

    Phosphorus elimination from aqueous solution using 'zirconium loaded okara' as a biosorbent

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    This work deals with the capture of phosphorus from aqueous solutions by biosorption onto zirconium loaded okara (ZLO). The batch-mode experiments were conducted to examine the effect of pH, biosorbent dose, initial phosphorus concentration, contact time, and temperature on the process. It was found that, the adsorption was most favored in the pH range of 2-6. The optimal doses for the adsorption, at initial phosphorus concentrations of 5, 10, 25, 50mg/L were 2, 3, 7, 10g/L, respectively. The maximum adsorption capacity of ZLO was approximately 44.13mg PO4/g at 298K. The phosphate removal was rapid, reaching 95% in 30min. Freundlich model best fitted the equilibrium data, while Pseudo-second order model satisfactorily described the kinetic results. Thermodynamic analysis revealed feasible, spontaneous, and endothermic nature of the process. The research would be beneficial for developing a promising, eco-friendly phosphorus biosorbent from a plentiful AWB - okara. © 2014 Elsevier Ltd

    Bioprocessing for elimination antibiotics and hormones from swine wastewater

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    © 2017 Elsevier B.V. Antibiotics and hormones in swine wastewater have become a critical concern worldwide due to the severe threats to human health and the eco-environment. Removal of most detectable antibiotics and hormones, such as sulfonamides (SAs), SMs, tetracyclines (TCs), macrolides, and estrogenic hormones from swine wastewater utilizing various biological processes were summarized and compared. In biological processes, biosorption and biodegradation are the two major removal mechanisms for antibiotics and hormones. The residuals in treated effluents and sludge of conventional activated sludge and anaerobic digestion processes can still pose risks to the surrounding environment, and the anaerobic processes’ removal efficiencies were inferior to those of aerobic processes. In contrast, membrane bioreactors (MBRs), constructed wetlands (CWs) and modified processes performed better because of their higher biodegradation of toxicants. Process modification on activated sludge, anaerobic digestion and conventional MBRs could also enhance the performance (e.g. removing up to 98% SMs, 88.9% TCs, and 99.6% hormones from wastewater). The hybrid process combining MBRs with biological or physical technology also led to better removal efficiency. As such, modified conventional biological processes, advanced biological technologies and MBR hybrid systems are considered as a promising technology for removing toxicants from swine wastewater

    Comparing the value of bioproducts from different stages of anaerobic membrane bioreactors

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    © 2016 Elsevier Ltd The anaerobic digestion process in anaerobic membrane bioreactors is an effective way for waste management, energy sustainability and pollution control in the environment. This digestion process basically involves the production of volatile fatty acids and biohydrogen as intermediate products and methane as a final product. This paper compares the value of bioproducts from different stages of anaerobic membrane bioreactors through a thorough assessment. The value was assessed in terms of technical feasibility, economic assessment, environmental impact and impact on society. Even though the current research objective is more inclined to optimize the production of methane, the intermediate products could also be considered as economically attractive and environment friendly options. Hence, this is the first review study to correlate the idea into an anaerobic membrane bioreactor which is expected to guide future research pathways regarding anaerobic process and its bioproducts

    High-Fidelity Tissue Engineering of Patient-Specific Auricles for Reconstruction of Pediatric Microtia and Other Auricular Deformities

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    Introduction: Autologous techniques for the reconstruction of pediatric microtia often result in suboptimal aesthetic outcomes and morbidity at the costal cartilage donor site. We therefore sought to combine digital photogrammetry with CAD/CAM techniques to develop collagen type I hydrogel scaffolds and their respective molds that would precisely mimic the normal anatomy of the patient-specific external ear as well as recapitulate the complex biomechanical properties of native auricular elastic cartilage while avoiding the morbidity of traditional autologous reconstructions. Methods: Three-dimensional structures of normal pediatric ears were digitized and converted to virtual solids for mold design. Image-based synthetic reconstructions of these ears were fabricated from collagen type I hydrogels. Half were seeded with bovine auricular chondrocytes. Cellular and acellular constructs were implanted subcutaneously in the dorsa of nude rats and harvested after 1 and 3 months. Results: Gross inspection revealed that acellular implants had significantly decreased in size by 1 month. Cellular constructs retained their contour/projection from the animals' dorsa, even after 3 months. Post-harvest weight of cellular constructs was significantly greater than that of acellular constructs after 1 and 3 months. Safranin O-staining revealed that cellular constructs demonstrated evidence of a self-assembled perichondrial layer and copious neocartilage deposition. Verhoeff staining of 1 month cellular constructs revealed de novo elastic cartilage deposition, which was even more extensive and robust after 3 months. The equilibrium modulus and hydraulic permeability of cellular constructs were not significantly different from native bovine auricular cartilage after 3 months. Conclusions: We have developed high-fidelity, biocompatible, patient-specific tissue-engineered constructs for auricular reconstruction which largely mimic the native auricle both biomechanically and histologically, even after an extended period of implantation. This strategy holds immense potential for durable patient-specific tissue-engineered anatomically proper auricular reconstructions in the future. © 2013 Reiffel et al

    MiR-637 maintains the balance between adipocytes and osteoblasts by directly targeting Osterix

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    Bone development is dynamically regulated by homeostasis, in which a balance between adipocytes and osteoblasts is maintained. Disruption of this differentiation balance leads to various bone-related metabolic diseases, including osteoporosis. In the present study, a primate-specific microRNA (miR-637) was found to be involved in the differentiation of human mesenchymal stem cells (hMSCs). Our preliminary data indicated that miR-637 suppressed the growth of hMSCs and induced S-phase arrest. Expression of miR-637 was increased during adipocyte differentiation (AD), whereas it was decreased during osteoblast differentiation (OS), which suggests miR-637 could act as a mediator of adipoosteogenic differentiation. Osterix (Osx), a significant transcription factor of osteoblasts, was shown to be a direct target of miR-637, which significantly enhanced AD and suppressed OS in hMSCs through direct suppression of Osx expression. Furthermore, miR-637 also significantly enhanced de novo adipogenesis in nude mice. In conclusion, our data indicated that the expression of miR-637 was indispensable for maintaining the balance of adipocytes and osteoblasts. Disruption of miR-637 expression patterns leads to irreversible damage to the balance of differentiation in bone marrow. © 2011 Zhang et al.published_or_final_versio

    Type I interferon signaling deficiency results in dysregulated innate immune responses to SARS-CoV-2 in mice

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    SARS-CoV-2 is a newly emerged coronavirus, causing the global pandemic of respiratory coronavirus disease (COVID-19). The type I interferon (IFN) pathway is of particular importance for anti-viral defence and recent studies identified that type I IFNs drive early inflammatory responses to SARS-CoV-2. Here, we use a mouse model of SARS-CoV-2 infection, facilitating viral entry by intranasal recombinant Adeno-Associated Virus (rAAV) transduction of hACE2 in wildtype (WT) and type I IFN-signalling-deficient (Ifnar1-/- ) mice, to study type I IFN signalling deficiency and innate immune responses during SARS-CoV-2 infection. Our data show that type I IFN signaling is essential for inducing anti-viral effector responses to SARS-CoV-2, control of virus replication and to prevent enhanced disease. Furthermore, hACE2-Ifnar1-/- mice had increased gene expression of the chemokine Cxcl1 and airway infiltration of neutrophils as well as a reduced and delayed production of monocyte-recruiting chemokine CCL2. hACE2-Ifnar1-/- mice showed altered recruitment of inflammatory myeloid cells to the lung upon SARS-CoV-2 infection, with a shift from Ly6C+ to Ly6C- expressing cells. Together, our findings suggest that type I IFN deficiency results in a dysregulated innate immune response to SARS-CoV-2 infection. This article is protected by copyright. All rights reserved

    Pheromone Binding to General Odorant-binding Proteins from the Navel Orangeworm

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    General odorant-binding proteins (GOBPs) of moths are postulated to be involved in the reception of semiochemicals other than sex pheromones, the so-called “general odorants.” We have expressed two GOBPs, AtraGOBP1 and AtraGOBP2, which were previously isolated from the antennae of the navel orangeworm, Amyelois transitella. Surprisingly, these two proteins did not bind compounds that are known to attract adult moths, particularly females. The proper folding and functionality of the recombinant proteins was inferred from circular dichroism analysis and demonstration that both GOBPs bound nonanal in a pH-dependent manner. EAG experiments demonstrated that female attractants (1-phenylethanol, propionic acid phenyl ester, and isobutyric acid phenyl ester) are detected with high sensitivity by the antennae of day-0 to day-4 adult females, with response declining in older moths. The same age-dependence was shown for male antennae responding to constituents of the sex pheromone. Interestingly, AtraGOBP2 bound the major constituent of the sex pheromone, Z11Z13-16Ald, with affinity comparable to that shown by a pheromone-binding protein, AtraPBP1. The related alcohol bound to AtraPBP1 with higher affinity than to AtraGOBP2. AtraGOBP1 bound both ligands with low but nearly the same affinity

    Silicene spintronics: Fe(111)/silicene system for efficient spin injection

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