216 research outputs found
Coherent Destruction of Tunneling and Dark Floquet State
We study a system of three coherently coupled states, where one state is
shifted periodically against the other two. We discover such a system possesses
a dark Floquet state at zero quasienergy and always with negligible population
at the intermediate state. This dark Floquet state manifests itself dynamically
in terms of the suppression of inter-state tunneling, a phenomenon known as
coherent destruction of tunneling. We suggest to call it dark coherent
destruction of tunneling (DCDT). At high frequency limit for the periodic
driving, this Floquet state reduces to the well-known dark state widely used
for STIRAP. Our results can be generalized to systems with more states and can
be verified with easily implemented experiments within current technologies.Comment: 5 pages, 3 figure
Biogeographical Variation and Population Genetic Structure of Sporisorium scitamineum
A total of 100 Sporisorium scitamineum isolates were investigated by inter simple sequence repeat (ISSR) and single primer-sequence related amplified polymorphism (SP-SRAP) markers. These isolates were clearly assorted into three distinct clusters regardless of method used: either cluster analysis or by principal component analysis (PCA) of the ISSR, SP-SRAP, or ISSR + SP-SRAP data set. The total gene diversity (Ht) and gene diversity between subpopulations (Hs) were estimated to be 0.34 to 0.38 and 0.22 to 0.29, respectively, by analyzing separately the ISSR and SP-SRAP data sets, and to be 0.26–0.36 by analyzing ISSR + SP-SRAP data set. The gene diversity attributable to differentiation among populations (Gst) was estimated to be 0.35 and 0.22, and the gene flow (Nm) was 0.94 and 1.78, respectively, when analyzing separately ISSR and SP-SRAP data set, and was 0.27 and 1.33, respectively, when analyzing ISSR + SP-SRAP data set. Our study showed that there is considerable genetic variation in the analyzed 100 isolates, and the environmental heterogeneity has played an important role for this observed high degree of variation. The genetic differentiation of sugarcane smut fungus depends to a large extent on the heterogeneity of their habitats and is the result of long-term adaptations of pathogens to their ecological environments
Genetic Diversity Analysis of Sugarcane Parents in Chinese Breeding Programmes Using gSSR Markers
Sugarcane is the most important sugar and bioenergy crop in the world. The selection and combination of parents for crossing rely on an understanding of their genetic structures and molecular diversity. In the present study, 115 sugarcane genotypes used for parental crossing were genotyped based on five genomic simple sequence repeat marker (gSSR) loci and 88 polymorphic alleles of loci (100%) as detected by capillary electrophoresis. The values of genetic diversity parameters across the populations indicate that the genetic variation intrapopulation (90.5%) was much larger than that of interpopulation (9.5%). Cluster analysis revealed that there were three groups termed as groups I, II, and III within the 115 genotypes. The genotypes released by each breeding programme showed closer genetic relationships, except the YC series released by Hainan sugarcane breeding station. Using principle component analysis (PCA), the first and second principal components accounted for a cumulative 76% of the total variances, in which 43% were for common parents and 33% were for new parents, respectively. The knowledge obtained in this study should be useful to future breeding programs for increasing genetic diversity of sugarcane varieties and cultivars to meet the demand of sugarcane cultivation for sugar and bioenergy use
Analysis of risk factors of postpartum anxiety in women undergoing cesarean section
Objective To explore the incidence and risk factors of postpartum anxiety in women undergoing cesarean section after comprehensive implementation of the second child policy. Methods A total of 154 women undergoing elective cesarean section were selected. Maternal clinical data were collected at preoperative 1 d, postoperative 2 d and 6 weeks. Self-Rating Anxiety Scale (SAS) and Edinburgh Postpartum Depression Scale (EPDS) were investigated at preoperative 1 d and postoperative 6 weeks. All parturients were divided into the anxiety group and normal group according to the SAS score at postoperative 6 weeks. Univariate and multivariate Logistic regression analyses were used to explore the risk factors of postpartum anxiety. Results The activity pain at postoperative 24 h,the time of first offbed activity after operation, the time of catheter removal, the length of hospital stay, maternal total dissatisfaction with postpartum recuperation period (doing the month) were significantly associated with postpartum anxiety (all P < 0.05). Multivariable logistic regression analysis showed that the total dissatisfaction with postpartum recuperation period (doing the month) (OR=7.741, 95%CI: 3.612-16.591, P < 0.001) was an independent risk factor for postpartum anxiety at 6 weeks after cesarean section. Conclusions The incidence of postpartum anxiety at postoperative 6 weeks is high in women undergoing cesarean section. Increasing maternal satisfaction with postpartum recuperation period can reduce the incidence of postpartum anxiety
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RpoN (σ54) Is Required for Floc Formation but Not for Extracellular Polysaccharide Biosynthesis in a Floc-Forming Aquincola tertiaricarbonis Strain.
Some bacteria are capable of forming flocs, in which bacterial cells become self-flocculated by secreted extracellular polysaccharides and other biopolymers. The floc-forming bacteria play a central role in activated sludge, which has been widely utilized for the treatment of municipal sewage and industrial wastewater. Here, we use a floc-forming bacterium, Aquincolatertiaricarbonis RN12, as a model to explore the biosynthesis of extracellular polysaccharides and the regulation of floc formation. A large gene cluster for exopolysaccharide biosynthesis and a gene encoding the alternative sigma factor RpoN1, one of the four paralogues, have been identified in floc formation-deficient mutants generated by transposon mutagenesis, and the gene functions have been further confirmed by genetic complementation analyses. Interestingly, the biosynthesis of exopolysaccharides remained in the rpoN1-disrupted flocculation-defective mutants, but most of the exopolysaccharides were secreted and released rather than bound to the cells. Furthermore, the expression of exopolysaccharide biosynthesis genes seemed not to be regulated by RpoN1. Taken together, our results indicate that RpoN1 may play a role in regulating the expression of a certain gene(s) involved in the self-flocculation of bacterial cells but not in the biosynthesis and secretion of exopolysaccharides required for floc formation.IMPORTANCE Floc formation confers bacterial resistance to predation of protozoa and plays a central role in the widely used activated sludge process. In this study, we not only identified a large gene cluster for biosynthesis of extracellular polysaccharides but also identified four rpoN paralogues, one of which (rpoN1) is required for floc formation in A. tertiaricarbonis RN12. In addition, this RpoN sigma factor regulates the transcription of genes involved in biofilm formation and swarming motility, as previously shown in other bacteria. However, this RpoN paralogue is not required for the biosynthesis of exopolysaccharides, which are released and dissolved into culture broth by the rpoN1 mutant rather than remaining tightly bound to cells, as observed during the flocculation of the wild-type strain. These results indicate that floc formation is a regulated complex process, and other yet-to-be identified RpoN1-dependent factors are involved in self-flocculation of bacterial cells via exopolysaccharides and/or other biopolymers
Governance of the business environment based on food safety disputes: empirical analysis based on the case of “Cordyceps sinensis”
IntroductionThe use of the fungus Cordyceps sinensis (CS), which has a long history of use in China for its tonic properties, has sparked controversy based on the risk from high arsenic levels in CS.MethodsThis study collected all 24 online dispute cases related to CS from the China Legal Documents Network. Excel software was applied to fit the distribution of the sample data and analyze the trend of trial results of CS disputes and the tendency of professional claims trials. The analysis covers the trend of trial results of contract dispute cases involving CS products (CDCCS), and the tendency of the results of CDCCS, using correlation to analyze the factors influencing the results. We analyzed trial tendencies in CDCCS by the methods of complex network analysis (Gephi software) to explore each factor’s effect on the trial outcome of in these claims cases and to predict the trial outcomes of new cases. Simultaneously use KNN to train and predict CS cases.ResultsThe peak number of trial cases was in 2018, and there has been a gradual increase in the rate of losing claims on the claimant. Correlation analysis was used to obtain that the likelihood of the defendant winning a claim is positively correlated with DR, FSS, IDP, and KSP, and negatively correlated with the adoption of JIFDD (3), JIFDD (15), and APL. Gephi software was used to conduct a complex network analysis of the factors influencing the tendency of trial results in CS disputes, showing that noncompliance with FSS, existence of KSP, and submission of IDP evidence by the buyer are the direct factors influencing the seller’s defeat. The seller’s “failure to perform DR” is the key factor in the seller’s defeat in cases. On this basis a probability function is developed to predict a trial win rate of 0.7803 for freshman cases, classifier to predict the remaining four samples and new cases, and get the prediction accuracy is 0.8, 95% CI: (0.2836, 0.9949), and the latter was higher than the former.DiscussionIt is concluded that the attribute of CS products is a scientific issue, the jurisdiction of CS disputes is confusing and needs to be clarified, and the application of the provisions in judicial trials is cannot adapt to the current environment and needs to be resolved. This study advocates that the government design policy from the top and establish a study on the boundary between administrative and judicial functions to provide a theoretical guarantee to circumvent lazy administration and unscientific law enforcement. The government can provide a legal and regulatory system to improve food quality and regulate management
The role of phosphodiesterase 12 (PDE12) as a negative regulator of the innate immune response and the discovery of antiviral inhibitors
2',5'-Oligoadenylate synthetase (OAS) enzymes and RNase-L constitute a major effector arm of interferon (IFN)-mediated antiviral defense. OAS produces a unique oligonucleotide second messenger, 2',5'-oligoadenylate (2-5A), that binds and activates RNase-L. This pathway is down-regulated by virus- and host-encoded enzymes that degrade 2-5A. Phosphodiesterase 12 (PDE12) was the first cellular 2-5A- degrading enzyme to be purified and described at a molecular level. Inhibition of PDE12 may up-regulate the OAS/RNase-L pathway in response to viral infection resulting in increased resistance to a variety of viral pathogens. We generated a PDE12-null cell line, HeLaΔPDE12, using transcription activator-like effector nuclease-mediated gene inactivation. This cell line has increased 2-5A levels in response to IFN and poly(I-C), a double-stranded RNA mimic compared with the parental cell line. Moreover, HeLaΔPDE12 cells were resistant to viral pathogens, including encephalomyocarditis virus, human rhinovirus, and respiratory syncytial virus. Based on these results, we used DNA-encoded chemical library screening to identify starting points for inhibitor lead optimization. Compounds derived from this effort raise 2-5A levels and exhibit antiviral activity comparable with the effects observed with PDE12 gene inactivation. The crystal structure of PDE12 complexed with an inhibitor was solved providing insights into the structure-activity relationships of inhibitor potency and selectivity
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