33 research outputs found

    Molecular Identification of Multidrug-Resistant Campylobacter Species From Diarrheal Patients and Poultry Meat in Shanghai, China

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    Emerging resistance to the antimicrobial agents of choice for treatment of thermophilic Campylobacter infections is becoming a serious threat to public health. In this study, 548 Campylobacter (372 C. jejuni and 176 C. coli) isolates from diarrheal patients and poultry meat were subjected for antibiotic susceptibility analysis to ciprofloxacin, tetracycline, gentamicin, erythromycin and clindamycin. Among them, 151 Campylobacter (32 C. jejuni and 119 C. coli) were identified as multidrug resistant isolates. PFGE analysis was performed on the 151 multidrug resistant isolates to determine their genetic relatedness, and 103 PFGE genotypes were determined. Some isolates from both human and chicken belonged to identical genotypes, indicating these clones might be able to spread between human and chicken. Antibiotic resistant genes of the 151 isolates were identified. The numbers of isolates carried tet (O), aadE, ermB, and aadE-sat4-aphA were 148 (98%), 89 (58.9%), 31 (20.5%), and 10 (6.6%), respectively. Almost all (n = 150, 99.3%) had gyrA mutation at codon 86. And the 23s rRNA A2075G point mutation was found in 56 (37.1%) isolates. Gene mutations at the cmeR-cmeABC intergenic region may lead to the activation of CmeABC multidrug efflux pump, and in this study novel sequence types of the intergenic region were identified in both C. jejuni and C. coli. This study determined the genetic prerequisites for antibiotic resistance of multidrug resistant Campylobacter isolates from diarrheal patients and poultry meat in Shanghai, China

    Phosphomolybdic acid-responsive Pickering emulsions stabilized by ionic liquid functionalized Janus nanosheets

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    <p><b>A</b> Representative photomicrographs of Caspase-3 immunofluorescence staining (400×). <b>B</b> Quantification of Caspase-3 fluorescence intensity in different groups. <b>C</b> Representative Western blot band of Caspase-3 activation in the ischemic cortex at 24 h after reperfusion. <b>D</b> Effect of LBP (40 mg/kg) on the Caspase-3 activation in MCAO mice cortex at 24 h after reperfusion. Data are expressed as mean±SEM (n = 6). <sup>##</sup>P<0.01 vs. sham-operated group; **P<0.01 vs. vehicle group.</p

    High-Level PM2.5/PM10 Exposure Is Associated With Alterations in the Human Pharyngeal Microbiota Composition

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    Previous studies showed that high concentration of particulate matter (PM) 2.5 and PM10 carried a large number of bacterial and archaeal species, including pathogens and opportunistic pathogens. In this study, pharyngeal swabs from 83 subjects working in an open air farmer’s market were sampled before and after exposure to smog with PM2.5 and PM10 levels up to 200 and 300 μg/m3, respectively. Their microbiota were investigated using high-throughput sequencing targeting the V3–V4 regions of the 16S rRNA gene. The genus level phylotypes was increased from 649 to 767 in the post-smog pharyngeal microbiota, of which 142 were new and detected only in the post-smog microbiota. The 142 new genera were traced to sources such as soil, marine, feces, sewage sludge, freshwater, hot springs, and saline lakes. The abundance of the genera Streptococcus, Haemophilus, Moraxella, and Staphylococcus increased in the post-smog pharyngeal microbiota. All six alpha diversity indices and principal component analysis showed that the taxonomic composition of the post-smog pharyngeal microbiota was significantly different to that of the pre-smog pharyngeal microbiota. Redundancy analysis showed that the influences of PM2.5/PM10 exposure and smoking on the taxonomic composition of the pharyngeal microbiota were statistically significant (p &lt; 0.001). Two days of exposure to high concentrations of PM2.5/PM10 changed the pharyngeal microbiota profiles, which may lead to an increase in respiratory diseases. Wearing masks could reduce the effect of high-level PM2.5/PM10 exposure on the pharyngeal microbiota

    MicroRNA Transcriptomic Analysis of Heterosis during Maize Seed Germination

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    Heterosis has been utilized widely in the breeding of maize and other crops, and plays an important role in increasing yield, improving quality and enhancing stresses resistance, but the molecular mechanism responsible for heterosis is far from clear. To illustrate whether miRNA-dependent gene regulation is responsible for heterosis during maize germination, a deep-sequencing technique was applied to germinating embryos of a maize hybrid, Yuyu22, which is cultivated widely in China and its parental inbred lines, Yu87-1 and Zong3. The target genes of several miRNAs showing significant expression in the hybrid and parental lines were predicted and tested using real-time PCR. A total of 107 conserved maize miRNAs were co-detected in the hybrid and parental lines. Most of these miRNAs were expressed non-additively in the hybrid compared to its parental lines. These results indicated that miRNAs might participate in heterosis during maize germination and exert an influence via the decay of their target genes. Novel miRNAs were predicted follow a rigorous criterion and only the miRNAs detected in all three samples were treated as a novel maize miRNA. In total, 34 miRNAs belonged to 20 miRNA families were predicted in germinating maize seeds. Global repression of miRNAs in the hybrid, which might result in enhanced gene expression, might be one reason why the hybrid showed higher embryo germination vigor compared to its parental lines

    Coseismic Source Model of the February 2023 Mw 6.8 Tajikistan Earthquake from Sentinel-1A InSAR Observations and Its Associated Earthquake Hazard

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    On 23 February 2023, an Mw 6.8 earthquake struck the border of Tajikistan and Xinjiang China, the source mechanism remains controversial according to different seismic inversions. To better comprehend the source characteristics and the surface deformation pattern, we used the ascending and descending orbital Sentinel-1A SAR data to obtain the coseismic deformation of this earthquake based on the traditional two-pass differential interferometric synthetic aperture radar (InSAR). The source model is inverted from the InSAR coseismic deformation results. The possible Coulomb Failure Stress (CFS) transfer is analyzed based on the preferred source model. The results illustrate that the earthquake ruptured a blind left-lateral strike-slip fault of strike 28.1° with a maximum slip of 1.53 m and the total geodetic moment is 1.99 × 1019 N·m (Mw 6.83). The strike direction and the fault characteristics suggest the Seismogenic fault is a secondary fault of the Sarez–Karakul Fault System. The 2015 Mw 7.2 Sarez Earthquake plays a triggering role in the occurrence of the 2023 Tajikistan earthquake. Earthquake hazard on Sarez–Karakul Fault System and Sarez–Murghab Thrust System is enhanced due to the Coulomb stress loaded by the Tajikistan earthquake

    Experimental measurement on the phase equilibria of the MgAgCu ternary system at 350 and 400C

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    ABSTRACT: The phase equilibria of the Mg–Ag–Cu ternary system at 350 and 400 °C were experimentally investigated using twenty-eight key samples. The phase equilibria and compositions in key samples were investigated using scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS). Powder X-ray diffraction (XRD) technique was used to analyze the crystal structure and solid solubility of compounds. Five three-phase equilibria and several two-phase equilibria have been determined at 350 and 400 °C. The solid solubility range of Cu in the compounds Mg3Ag, MgAg and fcc(Ag) were examined at 350 and 400 °C. The maximum solid solubility of Ag in the compound MgCu2 was found to be 11.46 at.% and 11.25 at.% with a constant value of about 66 at.% Cu at 350 and 400 °C, respectively. Besides, the solid solubility limits of Ag in the compounds Mg2Cu and fcc(Cu) were found to be less than 5 at.% at 350 and 400 °C. No ternary compound was observed in the present work

    Phase evolution and oxidation characteristics of the Nd–Fe–B and Ce–Fe–B magnet scrap powder during the roasting process

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    Many developed techniques for rare-earths’ (REs) recovery from magnet scraps are highly sensitive to the oxidative roasting process of scraps under high temperature. This study focused on phase evolution, microstructural changes and element distribution during the roasting of the widely used Nd–Fe–B and high-potential Ce–Fe–B scrap powders at 800°C. The sustained oxidation of Fe to Fe2O3 and the constant formation of composite RE oxides were the main reaction processes with increasing roasting cycles for the two scrap powders. The complete oxidation phases consisted of NdBO3, NdFeO3 and Fe2O3 for the Nd–Fe–B scrap powder, while the final products were NdBO3, GdFeO3 and Fe2O3 as well as individual CeO2 for the Ce–Fe–B scrap powder. An oxygen diffusion front was observed, forming a dark gray oxidized layer with almost the same thickness on the large particle surface. Additionally, a Fe2O3 layer covered the particle surface when the oxidation of the two scrap powders was complete. In oxidized Nd–Fe–B particles, the observed white regions corresponded to the oxidized intergranular Nd-rich phase as indicated by the almost same size and position before and after roasting. In Ce–Fe–B particles, the oxidized intergranular phase appeared to gather and grow, and a RE-rich layer appeared between the oxide/unoxidized layer. Conclusively, the iron-outward diffusion and the oxygen-inward diffusion were dominated by the oxidation of both Nd–Fe–B and Ce–Fe–B particles

    Spatiotemporal Coupling Coordination Analysis of Social Economy and Resource Environment of Central Cities in the Yellow River Basin

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    With the rapid economic and social development and accelerated urbanization, the negative ecological impact of major river basins worldwide has been deepening, which is gradually threatening the sustainable development of cities. This study establishes the model of the coupling coordination relationship between social economy and resources environment of nine central cities in the Yellow River Basin. Based on the evaluation index system of social economy and resource environment, we quantitatively measure the coupling coordination degree and spatiotemporal pattern of the nine central cities from 2010 to 2017. The obstacle factors of coupling coordination were then diagnosed based on the obstacle degree model. The results showed that (1) the social economy and resources environment development indices of the nine central cities in the Yellow River Basin, as well as the coupling coordination of each central city, showed an overall upward trend from 2010 to 2017. (2) Most of the central cities in the Yellow River Basin were in the coordinated coupling stage, among which Xining and Lanzhou have the highest coupling degree. (3) The obstacle factors affecting the harmonious development coupling coordination of the nine central cities were natural growth rate of population, proportion of tertiary industry in GDP and per capita investment in fixed assets in social economy system, and per capita green area of parks, per capita total amount of water resources, and per capita industrial SO2 emissions in resources environment system. It is necessary to adopt different strategies for different cities to promote the coupling coordination development of urban social economy and resources environment in the Yellow River Basin
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