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Background:Orientia tsutsugamushi is a zoonotic intracellular pathogen that requires parasitism in eukaryotic cells to reproduce. In recent years, tsutsugamushi disease reported in many places nationwide has crossed the Yangtze River, continuously, spreading to the North China. Now this phenomenon has aroused people's attention. Materials and Methods: In this study, meta-analysis was used to analyze the infection of rodents (vectors) in China, to clarify the transmission rule of O. tsutsugamushi. Results: This study included literature from six databases (PubMed, Web of Science, Science Direct, Wanfang, CNKI, and VIP). A total of 55 articles were included in the study from 610 retrieved articles. The total infection rate of O. tsutsugamushi in rodents was 5.5% (1206/20,620, 95% confidence interval [CI]: 0.0553–0.0617). The prevalence of O. tsutsugamushi in rodents before 2013 (7.73%, 95% CI: 4.11–12.37) was higher than after 2013 (2.11%, 95% CI: 0.64–4.41). O. tsutsugamushi spread among a variety of rodents, among which Rattus losea (13.3%, 95% CI: 4.33–26.26), Rattus tanezumi (5.69%, 95% CI: 1.37–12.72), and Apodemus agrarius (5.32%, 95% CI: 2.26–9.58) infection rate was higher. Kawasaki (8.32%, 95% CI: 1.42–20.17), Karp (7.36%, 95% CI: 2.62–14.22), Kato (2.54%, 95% CI: 0.08–8.28), and Gilliam (2.13%, 95% CI: 0.42–5.09) were the main prevalent genotypes in China. The prevalence of O. tsutsugamushi in rodents was seasonal, increasing gradually in summer (2.39%, 95% CI: 0.46–5.77), peaking in autumn (4.59%, 95% CI: 1.15–10.16), and then declining. The positive rate of immunofluorescence assay (25.07%, 95% CI: 8.44–46.88) was the highest among the detection methods, and it was statistically significant (p < 0.05). Based on the subgroup of geographical factors and climatic factors, the probability of O. tsutsugamushi infection in rodents was the highest when the temperature >19℃ (8.20%, 95% CI: 1.22–20.52), the altitude <100 millimeters (7.23%, 95% CI: 3.45–12.26), the precipitation >700 millimeters (12.22%, 95% CI: 6.45–19.50), and the humidity 60–70% (7.80%, 95% CI: 4.17–12.44). Conclusions: Studies have shown that rodents carrying O. tsutsugamushi are common. People should prevent and control rodents in life and monitor rodents carrying O. tsutsugamushi for a long time. [ABSTRACT FROM AUTHOR]

Cascade cyclization reactions of S3Ṗ−in situ generated from S2− with 1,3-enynes for the chemoselective synthesis of 2,3,5-trisubstituted thiophenes and 3-thienyl disulfides controlled by sulfide salts are developed. These two protocols provide new, environment-friendly and simple strategies to construct 2,3,5-trisubstituted thiophenes and 3-thienyl disulfides via the formation of two and six C–S bonds, respectively. [ABSTRACT FROM AUTHOR]

The water content of surface dead fuels is one of the most important indicators for forecasting fire danger and fire behaviors. We employed the timelag equilibrium water content methods (i.e. Nelson and Simard models) and the meteorological variable regression method to continuously measure the water content of surface dead fuels by one-hour time step from September to October in 2010 under Populus davidiana + Betula platyphylla, Picea koraiensis and the cutover lands (Pinus sylvestris var. mongolica + Betula platyphylla) with different canopy densities in Pangu Forestry Bureau, the Great Xing' an Mountains, Heilongjiang Province, China. We established prediction models and obtained prediction errors. The models were also used to extrapolate the water contents of surface dead fuels under other forest stands and the extrapolation accuracy was analyzed. The results showed that the mean absolute error, the mean relative error and the mean square error root of Nelson model (0.0154, 0.104 and 0.0226) were lower than those of Simard model (0.0185, 0.117 and 0.0256). In terms of extrapolation effects, the mean absolute error, the mean relative error and the mean square error root of meteorological variable regression method (0.0410, 0.0300 and 0.0740) were lower than those of Simard model (0.610, 0.492 and 0.846), but they were higher than those of Nelson model (0.034, 0.021 and 0.0660). Such results indicated that the time-lag equilibrium moisture content method by one-hour time step, especially Nelson model, was suitable for the forest stands in the Great Xing' an Mountains. Although extrapolation could not reduce the prediction errors, it could help improve the prediction accuracy and the efficiency of the present models applied to different forest stands or in a larger scale. The modeling and extrapolation errors were closely related to species identity and canopy densities, thus the appropriate timelag equilibrium moisture content methods should be selected according to different forest stands and locations. [ABSTRACT FROM AUTHOR]

This paper addresses the robust H ∞ control problem for continuous-time switched singular systems with uncertainties in the state, input, and derivative matrices. A two-phase method is proposed in this paper to optimize H ∞ performance and to minimize the upper bound of the average dwell time. First, sufficient conditions for finding a state feedback controller guaranteeing the minimum H ∞ disturbance attenuation are proposed. Besides, the average dwell time is obtained by solving linear matrices inequalities introduced in this paper. Second, to minimize the upper bound of the average dwell time, an improve average dwell time approach is put forward by introducing a new technique. And based on the result in the first phase, a new feedback controller, which optimizes H ∞ performance and minimizes the upper bound of the average dwell time is obtained by using the improved average dwell time approach. The point is that when the upper bound of the average dwell time is decreasing, H ∞ disturbance attenuation will increase and vice versa. Therefore, a trade-off should be built between H ∞ disturbance attenuation and average dwell time in practice. Finally, several numerical examples are presented to illustrate the effectiveness of the methods proposed. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is one of protozoan parasites resulting in zoonosis, which can infect nearly all of warm-blooded hosts, including humans and raccoon dogs ( Nyctereutes procyonoides ). However, related reports on prevalence and genetic characterization of T. gondii strains in raccoon dogs were few in China. The aim of this study was to survey the prevalence and genetic characterization of T. gondii strains in domestic raccoon dogs from Jilin, Liaoning, and Hebei provinces, northern China. During April 2016 to November 2017, a total of 337 tissue samples collected from domestic raccoon dogs were detected with B1 gene using a nested PCR. And the positive samples were genotyped at 11 genetic markers (SAG1, 5'-and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, L358, PK1, c22-8, c29-2, and Apico) using multilocus PCR-restriction fragment length polymorphism technology. Sixteen out of 337 sika deer (4.75%) were positive with B1 gene by nest PCR. Furthermore, four positive DNA samples were completely typed through further being genotyped, in which three samples were identified as ToxoDB Genotype #9, and one sample was confirmed as ToxoDB Genotype #10. The results of molecular detection not only revealed the existence of T. gondii in domestic raccoon dogs in Jilin, Liaoning, and Hebei for the first time, but also provided the information of genetic diversity. This study also indicated that ToxoDB Genotype #9 as a kind of potential reservoir for T. gondii transmission, may be main genotype in domestic raccoon dogs in China, posing a risk of infection in human health.

Cascade cyclization reactions of S3˙-in situ generated from S2- with 1,3-enynes for the chemoselective synthesis of 2,3,5-trisubstituted thiophenes and 3-thienyl disulfides controlled by sulfide salts are developed. These two protocols provide new, environment-friendly and simple strategies to construct 2,3,5-trisubstituted thiophenes and 3-thienyl disulfides via the formation of two and six C-S bonds, respectively.

The water content of surface dead fuels is one of the most important indicators for forecasting fire danger and fire behaviors. We employed the timelag equilibrium water content methods (i.e. Nelson and Simard models) and the meteorological variable regression method to continuously measure the water content of surface dead fuels by one-hour time step from September to October in 2010 under Populus davidiana + Betula platyphylla, Picea koraiensis and the cutover lands (Pinus sylvestris var. mongolica + Betula platyphylla) with different canopy densities in Pangu Forestry Bureau, the Great Xing'an Mountains, Heilongjiang Province, China. We established prediction models and obtained prediction errors. The models were also used to extrapolate the water contents of surface dead fuels under other forest stands and the extrapolation accuracy was analyzed. The results showed that the mean absolute error, the mean relative error and the mean square error root of Nelson model (0.0154, 0.104 and 0.0226) were lower than those of Simard model (0.0185, 0.117 and 0.0256). In terms of extrapolation effects, the mean absolute error, the mean relative error and the mean square error root of meteorological variable regression method (0.0410, 0.0300 and 0.0740) were lower than those of Simard model (0.610, 0.492 and 0.846), but they were higher than those of Nelson model (0.034, 0.021 and 0.0660). Such results indicated that the timelag equilibrium moisture content method by one-hour time step, especially Nelson model, was sui-table for the forest stands in the Great Xing'an Mountains. Although extrapolation could not reduce the prediction errors, it could help improve the prediction accuracy and the efficiency of the present models applied to different forest stands or in a larger scale. The modeling and extrapolation errors were closely related to species identity and canopy densities, thus the appropriate timelag equilibrium moisture content methods should be selected according to different forest stands and locations.

S 3 •- -mediated [1 + 2 + 2] and [1 + 3 + 1] cycloaddition reactions of aromatic alkynes to give tetraphenylthiophene and 2-benzylidenetetrahydrothiophene derivatives via two C-S bond formations are developed. These two protocols provide new, simple, and straightforward strategies to construct tetraphenylthiophene and 2-benzylidenetetrahydrothiophene derivatives under transition-metal-free conditions. This study also expands the application of S 3 •- in organic reactions.

Biological dusulfurizaion of petroleum feedstocks and products may offer an attractive alternative to reduce sulfur oxide emissions that cause serious environmental pollution. Dibenzothiophene (DBT), a model of organic sulfur compound in petroleum, can be microbially desulfurized without degradation of the organic structure by 4S pathway. Three desulfurization enzymes (DszA, DszB and DszC) and flavin reductase (DszD) are involved in sulfur-specific DBT desulfurization. DszA and DszC are FMNH2-dependent monoxygenases, FMNH2 is provided from the freely diffusible FMNH2 pool in the cell, and is replenished by DszD. So, co-expression of the desulfurization enzymes and flavin reductase can enhance the rate of sulfur removal. In the present work two incompatible plasmids: pBADD and paN2 were constructed. The paN2 allows Escherichia coli to liberate the sulfur of DBT and DBTs and pBADD produces a flavin reductase. They were co-expressed in Escherichia coli B121 (DE3). The soluble products of DszA, DszB, DszC and DszD accounted for 7.6%, 3.5%, 3.1% and 18% of the total proteins in co-expressed system. The desulfurization rate of lysate of E. coli BL21- pBADD + paN2 is 12.03 micromol/(h x mg) Dsz protein and about 5.4-fold of that of E. coli BL2-paN2. Experiment were also conducted using resting cell with the 0.6 wt% DBT in n-hexadecane as model diesel oil. After 24 hours reaction, 0.42 mmol/L (about 84%) DBT was converted to 2-HBP by E. coli BL21- pBADD + paN2, however, there was only 0.08 mmol/L (about 16%) DBT was desulfurized by E. coli BL2-paN2. The maximum desulfurization rate of E.coli BL21-pBADD + paN2 is about 67 micromol/h. The result shows that DszD enhances the rate of 2-HBP production when co-expressed in vivo with the desulfurization enzymes.