To estimate the basic reproduction number of the Wuhan novel coronavirus (2019-nCoV).
Based on the susceptible-exposed-infected-removed (SEIR) compartment model and the assumption that the infectious ...cases with symptoms occurred before 26 January, 2020 are resulted from free propagation without intervention, we estimate the basic reproduction number of 2019-nCoV according to the reported confirmed cases and suspected cases, as well as the theoretical estimated number of infected cases by other research teams, together with some epidemiological determinants learned from the severe acute respiratory syndrome (SARS).
The basic reproduction number fall between 2.8 and 3.3 by using the real-time reports on the number of 2019-nCoV-infected cases from People's Daily in China and fall between 3.2 and 3.9 on the basis of the predicted number of infected cases from international colleagues.
The early transmission ability of 2019-nCoV is close to or slightly higher than SARS. It is a controllable disease with moderate to high transmissibility. Timely and effective control measures are needed to prevent the further transmissions.
Hong Qu glutinous rice wine (HQGRW), as one of the most typical representatives of Chinese rice wine, is generally brewed from glutinous rice by adding two traditional wine fermentation starters—Hong ...Qu (HQ) and Bai Qu (BQ). The objective of this study was to determine the microbial communities and volatile metabolites of different traditional fermentation starters for HQGRW, and elucidate the potential correlation between microbiota and volatile metabolites. Both heatmap and principal component analysis (PCA) revealed the significant variances in volatile profiles among different wine starters. Microbiological analysis based on high-throughput sequencing (HTS) technology demonstrated that both of bacterial and fungal communities varied significantly in different starters. HQ was dominated mainly by bacteria of Bacillus ginsengihumi (20.17%), Pantoea sp. (10.39%), Elizabethkingia sp. (5.52%), Streptococcus sp. (5.03%) Brevundimonas sp. (3.03%), Rickettsia prowazekii (2.94%), Thermus thermophilus (2.54%), Bacillus amyloliquefaciens (1.48%), Bacillus aryabhattai (1.42%); fungi of Monascus purpureus (39.7%), Aspergillus niger (27.35%), Xeromyces bisporus (8.39%), Aspergillus penicillioides (6.89%), Aspergillus flavus (2.33%) and Pichia farinose (0.79%). By contrast, BQ contained much higher proportions of bacteria of Lactococcus lactis (10.45%), Lactobacillus brevis (9.99%), Pediococcus pentosaceus (8.29%), Weissella paramesenteroides (6.69%), Lactobacillus fermentum (4.83%), Gluconobacter thailandicus (3.93%), Lactobacillus alimentarius (3.59%), fungi of Rhizopus arrhizus (31.47%), Saccharomycopsis fibuligera (27.86%), Aspergillus niger (20.81%), Issatchenkia orientalis (3.79%), Saccharomycopsis malanga (3.15%), Clavispora lusitaniae (2.29%), Candida tropicalis (1.47%), Saccharomyces cerevisiae (1.11%) and Rhizopus microsporus (0.57%). Furthermore, core functional microbiota that might contribute to volatile flavour development was explored through Spearman's correlation-based network analysis. Lactobacillus brevis, Lactobacillus alimentarius, Lactobacillus plantarum and Aspergillus niger were found to be strongly associated with acid compounds (FDR adjusted P < 0.01), while Pichia sp., Candida sp., Monascus purpureus, Lactobacillus brevis and Lactobacillus alimentarius were positively correlated with concentrations of aromatic esters associated with fruity and floral notes (FDR adjusted P < 0.01), implying that these microorganisms might make significant contributions to the flavour of rice wine. These findings demonstrated that the aromatic quality of HQGRW may be critically influenced by the microbiota in traditional fermentation starters. To conclude, this study would contribute to the development of novel defined starter cultures for improving the aromatic quality of HQGRW.
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•HQGRW is brewed with two traditional fermentation starters—Hong Qu (HQ) and Bai Qu (BQ).•BQ was mainly dominated by L. lactis, L. brevis, R. arrhizus, and S. fibuligera.•HQ was mainly dominated by B. ginsengihumi, Pantoea sp., M. purpureus, and A. niger.•Microbial communities varied significantly in different traditional fermentation starters.•L. brevis, L. alimentarius, R. microspores, and M. purpureus were related to volatile alcohols and esters.
Polyploidy is ubiquitous and its consequences are complex and variable. A change of ploidy level generally influences genetic diversity and results in morphological, physiological and ecological ...differences between cells or organisms with different ploidy levels. To avoid cumbersome experiments and take advantage of the less biased information provided by the vast amounts of genome sequencing data, computational tools for ploidy estimation are urgently needed. Until now, although a few such tools have been developed, many aspects of this estimation, such as the requirement of a reference genome, the lack of informative results and objective inferences, and the influence of false positives from errors and repeats, need further improvement. We have developed ploidyfrost, a de Bruijn graph‐based method, to estimate ploidy levels from whole genome sequencing data sets without a reference genome. ploidyfrost provides a visual representation of allele frequency distribution generated using the ggplot2 package as well as quantitative results using the Gaussian mixture model. In addition, it takes advantage of colouring information encoded in coloured de Bruijn graphs to analyse multiple samples simultaneously and to flexibly filter putative false positives. We evaluated the performance of ploidyfrost by analysing highly heterozygous or repetitive samples of Cyclocarya paliurus and a complex allooctoploid sample of Fragaria × ananassa. Moreover, we demonstrated that the accuracy of analysis results can be improved by constraining a threshold such as Cramér's V coefficient on variant features, which may significantly reduce the side effects of sequencing errors and annoying repeats on the graphical structure constructed.
Microalgae have been emerging as an important source for the production of bioactive compounds. Marine diatoms can store high amounts of lipid and grow quite quickly. However, the genetic and ...biochemical characteristics of fatty acid biosynthesis in diatoms remain unclear. Glycerophospholipids are integral as structural and functional components of cellular membranes, as well as precursors of various lipid mediators. In addition, diacylglycerol acyltransferase (DGAT) is a key enzyme that catalyzes the last step of triacylglyceride (TAG) biosynthesis. However, a comprehensive sequence-structure and functional analysis of DGAT in diatoms is lacking. In this study, an isoform of diacylglycerol acyltransferase type 2 of the marine diatom Phaeodactylum tricornutum was characterized. Surprisingly, DGAT2 overexpression in P. tricornutum stimulated more oil bodies, and the neutral lipid content increased by 35%. The fatty acid composition showed a significant increase in the proportion of polyunsaturated fatty acids; in particular, EPA was increased by 76.2%. Moreover, the growth rate of transgenic microalgae remained similar, thereby maintaining a high biomass. Our results suggest that increased DGAT2 expression could alter fatty acid profile in the diatom, and the results thus represent a valuable strategy for polyunsaturated fatty acid production by genetic manipulation.
Antibiotic contaminants can migrate over long distances in the water, thus possibly causing severe detriment to the environment and even potential harm to human health. Heterogeneous activation of ...peroxymonosulfate (PMS) assisted by visible light is an emerging and promising technology for the purification of such wastewater. This study designed an ultra-efficient and stable PMS activator (FeCN) to restore the typical antibiotic-polluted water under harsh conditions. About 90.94% of sulfamethoxazole (SMX) was degraded in 35 min in the constructed FeCN+PMS/vis system, and the reaction rate constant was nearly 50-fold higher than direct photocatalysis. Electron spin resonance, quenching experiments, LC/MS technique, eco-toxicity assessment, and density functional theory validated that the SMX removal was dominated by the attack of h+, •O2- and 1O2 on the active atoms of SMX molecules with high Fukui index, presenting as a simultaneous degradation and detoxification process. Such a visible-light-assisted PMS activation system also had good resistance to the environmental water bodies and a broad spectrum in the degradation of various pollutants. In particular, Cl- (50 mM) could significantly accelerate the removal of SMX with a 32.6-fold increase in catalytic activity, and the mineralization efficiency could reach 56.6% under identical conditions. Moreover, this Cl- containing system excluded the degradation products of disinfection by-products, and such a system was also versatile for different contaminants. This work demonstrates the feasibility of the FeCN+PMS/vis system for the remediation of antibiotic-contaminated wastewater in the presence and absence of Cl-, and also highlights their great potential in WWTPs.
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•An eco-friendly FeCN-activated PMS under visible light was designed for antibiotic degradation.•Structure-activity relationship between active species and catalytic performance was investigated.•Cl- (from low to high) dramatically enhanced the removal and mineralization of sulfamethoxazole.•Multiple strategies revealed a simultaneous degradation and detoxification process.•The feasibility of the remediation of antibiotic-contaminated wastewater was confirmed.
Summary
Topological cytonuclear discordance is commonly observed in plant phylogenetic and phylogeographic studies, yet few studies have attempted to detect two other forms of cytonuclear discordance ...(branch length and geographical) and to uncover the causes of the discordance.
We used the whole nuclear and chloroplast genome data from 80 individual Asian butternuts to reveal the pattern and processes of cytonuclear discordance.
Our findings indicate that the chloroplast genome had substantially deeper divergence (branch‐length discordance) and a steeper cline in the contact zone (geographic discordance) compared with the nuclear genome. After various hypothesis have been tested, the results suggest that incomplete lineage sorting, positive selection and cytonuclear incompatibility are probably insufficient to explain this pattern. However, isolation‐by‐distance analysis and gene flow estimation point to a much higher level of gene flow by pollen compared with by seeds, which may have slowed down lineage divergence and mediated wider contact for nuclear genome compared with the chloroplast genome.
Altogether, this study highlights a critical role of sex‐biased dispersal in causing discordance between the nuclear and plastid genome of Asian butternuts. Given its ubiquity among plants, asymmetric gene flow should be given a high priority in future studies of cytonuclear discordance.
To achieve a parsimonious model, it is necessary to rank the importance of input variables according to some measures. The problem is nontrivial in the setting of nonlinear and nonparametric system ...identification. Difficulties lie in the lack of structural information of the unknown system, unknown underlying probabilistic distributions, and unknown nonlinear correlations of variables. In this article, we present a way to rank variables according to goodness of fit (GoF). Asymptotic results are established, and numerical algorithms are proposed. The problem is cast in a reproducing kernel Hilbert space (RKHS) that allows us to deal with nonparametric nature of the unknown system, to avoid making strong conditions on the unknown distributions, to link GoFs to computable conditional covariance operators on RKHS, and to develop computationally friendly numerical algorithms. Numerical simulations support the theoretical developments.
We investigated the molecular mechanisms underlying macrolide resistance in 38 strains of Campylobacter isolated from poultry. Twenty-seven strains were resistant to azithromycin and erythromycin, ...five showed intermediate azithromycin resistance and erythromycin susceptibility, and six showed azithromycin resistance and erythromycin susceptibility. Four Campylobacter jejuni and six Campylobacter coli strains had azithromycin MICs which were 8–16 and 2–8-fold greater than those of erythromycin, respectively. The A2075G mutation in the 23S rRNA gene was detected in 11 resistant strains with MICs ranging from 64 to ≥ 512 μg/mL. Mutations including V137A, V137S, and a six-amino acid insertion (114-VAKKAP-115) in ribosomal protein L22 were detected in the C. jejuni strains. Erythromycin ribosome methylase B-erm(B) was not detected in any strain. All strains except three showed increased susceptibility to erythromycin with twofold to 256-fold MIC change in the presence of phenylalanine arginine ß-naphthylamide (PAßN); the effects of PAßN on azithromycin MICs were limited in comparison to those on erythromycin MICs, and 13 strains showed no azithromycin MIC change in the presence of PAßN. Differences between azithromycin and erythromycin resistance and macrolide resistance phenotypes and genotypes were observed even in highly resistant strains. Further studies are required to better understand macrolide resistance in Campylobacter.
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Epoxy resins (EP) possessing superior flame retardancy, mechanical properties and glass transition temperature are urgently needed to meet the ever-increasing requirement of high ...performance for the practical application of EP. Herein, lamellar-like phosphorus-based triazole-zinc complex (Zn-PT) was firstly constructed through coordination reaction in a facile condition to address the above issue. The results revealed that Zn-PT was well dispersed in epoxy matrix, and with 3 wt% Zn-PT, the tensile strength, flexural strength and modulus of epoxy composites were remarkably increased from 71, 112 and 2982 MPa of neat epoxy resin (EP) to 80, 162 and 3482 MPa respectively. The glass transition temperature was higher than EP. Besides, the limiting oxygen index (LOI) increased to 28.3%, and UL-94V-1 level was available. Meanwhile, the cone calorimeter test (CCT) results showed that epoxy composites displayed less heat release and smoke production. Generally, this work provides a feasible strategy to prepare high-performance epoxy composites, which has the potential to satisfy the requirement of epoxy in the practical application.
Closed-loop artificial pancreas systems have been in development for several years, including assessment in numerous varied outpatient clinical trials. We aimed to summarise the efficacy and safety ...of artificial pancreas systems in outpatient settings and explore the clinical and technical factors that can affect their performance.
We did a systematic review and meta-analysis of randomised controlled trials comparing artificial pancreas systems (insulin only or insulin plus glucagon) with conventional pump therapy (continuous subcutaneous insulin infusion CSII with blinded continuous glucose monitoring CGM or unblinded sensor-augmented pump SAP therapy) in adults and children with type 1 diabetes. We searched Medline, Embase, and the Cochrane Central Register of Controlled Trials for studies published from 1946, to Jan 1, 2017. We excluded studies not published in English, those involving pregnant women or participants who were in hospital, and those testing adjunct medications other than glucagon. The primary outcome was the mean difference in percentage of time blood glucose concentration remained in target range (3·9-10 mmol/L or 3·9-8 mmol/L, depending on the study), assessed by random-effects meta-analysis. This study is registered with PROSPERO, number 2015:CRD42015026854.
We identified 984 reports; after exclusions, 27 comparisons from 24 studies (23 crossover and one parallel design) including a total of 585 participants (219 in adult studies, 265 in paediatric studies, and 101 in combined studies) were eligible for analysis. Five comparisons assessed dual-hormone (insulin and glucagon), two comparisons assessed both dual-hormone and single-hormone (insulin only), and 20 comparisons assessed single-hormone artificial pancreas systems. Time in target was 12·59% higher with artificial pancreas systems (95% CI 9·02-16·16; p<0·0001), from a weighted mean of 58·21% for conventional pump therapy (I
=84%). Dual-hormone artificial pancreas systems were associated with a greater improvement in time in target range compared with single-hormone systems (19·52% 95% CI 15·12-23·91 vs 11·06% 6·94 to 15·18; p=0·006), although six of seven comparisons compared dual-hormone systems to CSII with blinded CGM, whereas 21 of 22 single-hormone comparisons had SAP as the comparator. Single-hormone studies had higher heterogeneity than dual-hormone studies (I
79% vs 66%). Bias assessment characteristics were incompletely reported in 12 of 24 studies, no studies masked participants to the intervention assignment, and masking of outcome assessment was not done in 12 studies and was unclear in 12 studies.
Artificial pancreas systems uniformly improved glucose control in outpatient settings, despite heterogeneous clinical and technical factors.
None.
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