34 research outputs found

    Effect of additives on microstructure of coal-based graphite

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    The Taixi anthracite was used as the raw materials, and mixed with different masses of additives, namely silicon oxide, titanium oxide, and iron oxide, to prepare the coal-based graphite by high temperature graphitization. The microstructure of coal-based graphite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), laser confocal Raman spectroscopy (Raman) and Specific surface area and porosity analyzer.The results show that the graphitization degree of the coal-based graphite can reach over 89% after high temperature heat treatment at 2800 °C , which significantly improves the microcrystalline structure of anthracite and achieves orderly rearrangement of sp2 hybrid carbon atoms in the coal. Under the same additive mixing level, the graphitization degree and stacking height of coal-based graphite with titanium dioxide as additive are relatively high, the difference between the layer spacing and the ideal graphite layer spacing is the smallest, and the degree of ordering of carbon materials is the highest. The Raman spectroscopy results showed that the order degree of coal -based graphite prepared under different additives was significantly different, and the order degree of TXSC3, TXTC2 and TXIC3 coal-based graphite was the highest among the additives. Under the electron microscope, it is found that under the conditions of three additives, the scales, spherical and two shapes of coal-based graphite can be prepared separately. It can be seen from the specific surface area and pore size distribution data of coal-based graphite that they have similar low-temperature nitrogen adsorption-desorption isotherms

    Epidemiological and genomic analyses of human isolates of Streptococcus suis between 2005 and 2021 in Shenzhen, China

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    Streptococcus suis (S. suis) is an important food-borne zoonotic pathogen that causes swine streptococcosis, which threatens human health and brings economic loss to the swine industry. Three-quarters of human S. suis infections are caused by serotype 2. A retrospective analysis of human S. suis cases in Shenzhen, a megacity in China, with high pork consumption, between 2005 and 2021 was conducted to understand its genomic epidemiology, pathogen virulence, and drug resistance characteristics. The epidemiological investigation showed that human cases of S. suis in Shenzhen were mainly associated with people who had been in close contact with raw pork or other swine products. Whole-genome sequence analysis showed that 33 human isolates in Shenzhen were dominated by serotype 2 (75.76%), followed by serotype 14 (24.24%), and the most prevalent sequence types (STs) were ST7 (48.48%) and ST1 (39.40%). ST242 (9.09%) and ST25 (3.03%), which were rarely reported, were also found. Phylogenetic analysis showed that the Shenzhen human isolates had close genetic relatedness to isolates from Guangxi (China), Sichuan (China), and Vietnam. We found a new 82 KB pathogenicity island (PAI) in the serotype 2 isolate that may play a role in sepsis. Similarly, a serotype 14 isolate, containing 78 KB PAI, was isolated from a patient presenting with streptococcal toxic shock syndrome (STSLS) who subsequently died. Multi-drug resistance (MDR) was high in human isolates of S. suis from Shenzhen. Most human isolates were resistant to tetracycline, streptomycin, erythromycin, and clindamycin, and 13 isolates had intermediate resistance to penicillin. In conclusion, swine importation from Guangxi, Sichuan, and Vietnam should be more closely monitored, and the use of antibiotics limited to reduce the potential for antimicrobial resistance (AMR)

    CAR-based cell therapy: evaluation with bibliometrics and patent analysis

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    Chimeric antigen receptors-based cell therapies have shown impressive preclinical and clinical success and revolutionized biomedicine. However, the link between science and invention, the impact of international cooperation, and the influence and prestige of CARs research have not been explored. This study analyzed the landscape of peer-reviewed articles and patents related to CARs. A total of 5,681 publications were analyzed using bibliometrics and machine learning-based text mining to assess publication metrics, subject areas, and research hotspots. 5,010 Inpadoc families were also analyzed for patent filing trends, priority countries, and applicant and inventor rankings. The results show that CARs research has the following distinctive features: high research prestige among research community; strong global geographical bias in both academic output and patenting patterns; strong links between science and invention, but significant differences among countries; and an inverse relationship between country size and international collaboration rates

    Microbial community with the ability to biodegradation perchlorate in a bio-electrochemical reactor

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    In this study, the sediments from the Liuyang River (Hunan Province, China) were used as an inoculum to bio-reduction perchlorate in a bio-electrochemical reactor (BER). The efficient degradation of perchlorate was found in the BER by utilizing the hydrogen as electron donor. When the current intensity was 10 mA and HRT was 72 h, the removal rate of perchlorate (initial concentration was 5 mg/L) reached 84.13% and a removal flux of 178.68 mg/m2·d was achieved. High-throughput sequencing analysis confirmed that the biofilm in the reactor had been successfully acclimated, and the system could achieve perchlorate reduction effectively. Firmicutes and Bacteroidetes were the dominant phyla during inoculation phase, and Actinobacteriria, Proteobacteria, and Tenericutes also constituted a low proportion in the biofilm. Bacilli and Clostridia were dominant at class-level both in inoculum and biofilm, with the relative abundance about 56%-72% and 17%-23%, respectively. These results confirmed that the biofilm in the BER system had been successfully formed, and the BER system could biodegradation perchlorate effectively

    A Modified Molecular Beacons-Based Multiplex Real-Time PCR Assay for Simultaneous Detection of Eight Foodborne Pathogens in a Single Reaction and Its Application

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    National Natural Science Foundation of China [81071433]; Guangdong Provincial Natural Science Foundation [8151802003000006]; Basic Research Project of Shenzhen [JC201104220329A]Foodborne disease outbreaks are often caused by one of the major pathogens. Early identification of the causal pathogen is crucial for disease control and prevention. We describe a real-time polymerase chain reaction (rtPCR) assay that can identify, in a single reaction, up to eight common foodborne bacterial pathogens, including Salmonella enterica subsp. enterica, Listeria monocytogenes, Escherichia coli O157, Vibrio parahaemolyticus, V. vulnificus, Campylobacter jejuni, Enterobacter sakazakii, and Shigella spp. This multiplex rtPCR assay takes advantage of modified molecular beacons and the multicolor combinational probe coding strategy to discriminate each pathogen and the homo-tag assisted non-dimer (HAND) system to prevent dimer formation. The detection limits of the assay ranged from 1.3x10(3) colony-forming units (CFU)/g stool (L. monocytogenes) to 1.6x10(4) CFU/g stool (Shigella spp.). The target genes were 100% specific as assessed on 986 reference strains covering 41 species since no cross-reactions were observed. The assay was applied to the detection of foodborne pathogens in 11,167 clinical samples and the results were compared with culture methods for further validation. The sensitivity and specificity of the rtPCR were 100% and 99%, respectively. When performed in a 96-well rtPCR system, more than 90 samples could be analyzed within 3 h. Given the high accuracy, sensitivity, specificity, and short turn-around time, the established assay could be used for the rapid and reliable identification of the causative pathogens responsible for a certain foodborne disease outbreak and rapid screening of these major foodborne pathogens in laboratory-based surveillance of outpatient clinical samples or even food samples

    Pathogenetic detection, retrospective and pathogenicity analysis of a fatal case of Vibrio vulnificus in Shenzhen, China

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    Abstract We report a 36-year-old male patient died of V. vulnificus-induced septicaemia and multiple organ failure syndrome after oyster consumption at a restaurant. We isolated and identified V. vulnificus vv16015 from the patient’s blood sample and antibiotic susceptibility tests indicated sensitivity to all 21 antibiotics. Oyster samples were subsequently collected from the restaurant’s supplier and three strains of V. vulnificus were isolated. Whole genome sequencing and analysis revealed vv16015 to be distantly related to these strains and confirmed that V. vulnificus contamination was present in the seafood of the restaurant and supplier. Using a Galleria mellonella larvae infection model, the virulence of vv16015 was determined to be higher than that of comparison strains isolated from a surviving patient (vv15018) and an oyster (vv220015). The human and environment distribution of V. vulnificus in Shenzhen is sporadic and heterogeneous, and vv16015 is highly virulent compared to other strains

    Clonal Expansion of Biofilm-Forming Salmonella Typhimurium ST34 with Multidrug-Resistance Phenotype in the Southern Coastal Region of China

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    To disclose the antibiotics susceptibility and wide adaptability of commonly occurring genotypes of Salmonella Typhimurium, the antibiotic resistance and biofilm formation of different multi-locus sequence typing (MLST) types of a collection of 240 S. Typhimurium isolates (33 food and 207 clinical ones) during 2010–2014 in Shenzhen were analyzed. Among these strains, 167 was ST34 (69.58%), and 57 was ST19 (23.75%), respectively. A total of 159 (95.21%) ST34 strains displayed the multidrug resistant phenotype (≥ three classes of antibiotic), whereas only 23 (40.35%) ST19 ones did (P < 0.01). Moreover, a relative high proportion (72.46%) of ST34 isolates was classified as moderate to strong biofilm-producers, while only 15.79% of ST19 (P < 0.01) was. Among the food isolates, more than half (51.52%) were from livestock products, among which 41.18% classified as moderate to strong biofilm-producers. In summary, this study highlights the expansion of S. Typhimurium ST34 of strong biofilm-forming ability and multidrug resistance in the southern coastal region of China. Therefore, monitoring the occurrence of ST34 S. Typhimurium in food sources, especially in livestock products, and taking appropriate measures to control Salmonella spp. infections via decreasing biofilm formation should be addressed
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