53 research outputs found

    Antimikrobna rezistencija i svojstva virulencije bakterije Enterococcus faecium izolirane u goveda s kliničkim mastitisom iz pokrajine Ningxia, Kina

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    This study was conducted to determine the antimicrobial resistance and virulence traits of 32 Enterococcus faecium isolates from clinical bovine mastitis cases in Ningxia Province, China. In total, 32 E. faecium isolates were taken from subclinical bovine mastitis on the basis of morphological characterization and biochemical testing, and screened for antimicrobial susceptibility. The virulence genes of the isolates were studied using polymerase chain reaction (PCR). The disc diffusion assay revealed a high occurrence of resistance against tetracycline (78.1%) and erythromycin (68.8%) in the E. faecium isolates. However, all tested E. faecium were susceptible to linezolid and vancomycin. Moreover, all E. faecium isolates harbored the erythromycin-resistant genes ermA, ermB and ermC, as well as the tetracycline-resistant genes tetK, tetL and tetM. Furthermore, all E. faecium isolates carried more than 3 of the tested virulence genes. The presence of agg (100%), cpd (100%), efaA (100%), gelE (93.4%), and esp (75.0%) was found most frequently in all the tested isolates. These findings are useful for making appropriate antimicrobial choices and developing antivirulence therapies for subclinical bovine mastitis caused by E. faecium in Ningxia Province, China.Istraživanje je provedeno kako bi se odredila antimikrobina rezistencija i svojstva virulencije izolata bakterije Enterococcus faecium uzetih u goveda s kliničkim mastitisom. U ukupno 32 izolata goveda iz pokrajine Ningxia u Kini, procijenjena je antimikrobna osjetljivost na temelju morfološke karakterizacije i biokemijskih pretraga. Geni virulencije izolata istraženi su polimeraznom lančanom reakcijom (PCR). Disk-difuzijski test je u izolatu bakterije E. faecium pokazao visoku pojavnost rezistencije na tetraciklin (78,1 %) i eritromicin (68,8 %). Svi su pretraženi izolati bili osjetljivi na linezolid i vankomicin i imali gene rezisentne na eritromicin ermA, ermB i ermC, kao i na tetraciklin, tetK, tetL i tetM. Osim toga svi izolati E. faecium nosili su više od tri istraživana gena virulencije. Najčešći geni bili agg (100 %), cpd (100 %), efaA (100 %), gelE (93,4 %) i esp (75,0 %). Ovi rezultati mogu u pokrajini Ningxia u Kini pridonijeti pravilnom izboru antimikrobnog lijeka i razvoju uspješne terapije za supklinički goveđi mastitis uzrokovan bakterijom E. faecium

    In vitro propagation of katsura tree (Cercidiphyllum japonicum Sieb. Et Zucc), an endangered plant in China

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    Katsura tree (Cercidiphyllum japonicum Sieb. Et Zucc) is a long-lived, deciduous, wind-pollinated tree with dimorphic leaves. It is valued as an ornamental or a shade tree for landscape and a commercially valuable tree. Conventional propagation through seeds and cutting is not sufficient to satisfy the progressive demand. There is an exigent need to develop protocols for rapid propagation of katsura trees. This study reports an in vitro propogation of the tree. The work focused on assessing the effects of basal medium, plant growth regulators (PGRs) combination on shoot and root proliferation. Nodal sections of young shoots were used as explants. Shoot initiation, and shoot and root proliferation were carried out on basal medium and PGRs combination. The optimal response of shoot initiation was observed in woody plant medium (WPM) supplemented with 1.0 mg L−1BA and 0.01 mg L−1IBA (indole-3-butyric acid) and the percentage of shoot initiation was up to 91.66%. For proliferation of micropropagated shoots, three orthogonal designs were carried out. The result shows that the highest proliferation coefficient (4.83) was obtained in the medium containing 1.0 mg L−1 BA and 0.05 mg L−1 NAA. With the application of benzyladenine (BA) and naphthalene acetic acid (NAA), emerald green and vigorous shoots were observed. Shoots about 2.0 cm long with 4 to 6 leaves were excised and transferred to root propagation media. When the concentration of NAA was 0.5 mg L−1, the rooting percentage, mean number and mean length of roots were the highest, reaching 75% and 3.1 and 2.1 cm respectively. This efficient plant regeneration system would be helpful for genetic improvement through future conservation and biotechnology research.Keywords: Katsura tree (Cercidiphyllum japonicum Sieb. Et Zucc), shoot initiation, shoot propagation, root propagatio

    Synergistic Association of PTGS2 and CYP2E1 Genetic Polymorphisms with Lung Cancer Risk in Northeastern Chinese

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    BACKGROUND: Lung cancer is the most common cause of cancer-related deaths worldwide. The aim of this study was to investigate the association of five extensively-studied polymorphisms in PTGS2 (rs689466, rs5275, rs20417) and CYP2E1 (rs2031920, rs6413432) genes with lung cancer risk in a large northeastern Chinese population. METHODOLOGY/PRINCIPAL FINDINGS: This is a hospital-based case-control study involving 684 patients with lung cancer and 604 cancer-free controls. Genotyping was performed using the PCR-LDR method. Data were analyzed using Haplo.stats and MDR programs. There were significant differences between patients and controls in allele/genotype distributions of rs5275 (P = 0.002/0.003) and rs6413432 (P = 0.037/0.044), as well as in genotype distributions of rs689466 (P = 0.02). The risk for lung cancer associated with the rs5275-C mutant allele was decreased by 60% (95% CI [confidence interval]: 0.21-0.74; P = 0.004) under the recessive model. Carriers of rs689466-G mutant allele had a 28% (95% CI: 0.57-0.92; P = 0.008) reduced risk of developing lung cancer relative to the AA genotype carriers. In haplotype analysis, haplotype G-C-C-T (in order of rs689466, rs5275, rs2031920 and rs6413432) decreased the odds of lung cancer by 28% (95% CI: 0.51-0.93; P = 0.019) after adjusting for confounding factors, whereas haplotype A-T-T-T had 1.49-fold (95% CI: 1.21-1.79; P = 0.012) increased risk for lung cancer. Using MDR method, the overall best model including rs5275, rs689466 and rs6413432 polymorphisms was identified with a maximal testing accuracy of 66.1% and a maximal cross-validation consistency of 10 out of 10 (P = 0.003). CONCLUSIONS/SIGNIFICANCE: Our findings demonstrated a potentially synergistic association of PTGS2 and CYP2E1 polymorphisms with the underlying cause of lung cancer in northeastern Chinese

    Electro-Assisted Fe<sup>3+</sup>/Persulfate System for the Degradation of Bezafibrate in Water: Kinetics, Degradation Mechanism, and Toxicity

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    In this study, an electrochemical-assisted ferric ion/persulfate (EC/Fe3+/PS) process was proposed to degrade bezafibrate (BZF), a widespread hypolipidemic drug, in water. By promoting the reduction of Fe3+ to Fe2+ at the cathode, the introduction of an electric field successfully overcomes the limitation of non-regenerable Fe2+ inherent in Fe2+/PS systems, significantly improving the degradation efficiency of BZF. The predominant reactive species identified were •OH and SO4●−, with 1O2 also playing a role. Various key operational parameters were investigated and optimized, including the current intensity, Fe3+ dosage, PS concentration, and initial pH. With a current intensity of 50 mA, an Fe3+ concentration of 50 μΜ, a PS dosage of 50 μM, and an initial pH of 3, the degradation efficiency of BZF demonstrated an exceptional achievement, reaching up to 98.8% within 30 min. The influence of anions and humic acid was also assessed. An LC/TOF/MS analysis revealed four major degradation pathways of BZF: hydroxylation, amino bond cleavage, dechlorination, and fibrate chain removal. The acute and chronic toxicities of BZF and its degradation intermediates were then assessed using the ECOSAR program. These findings highlight the wide-ranging applications of the EC/Fe3+/PS system and its potential for remediating water contaminated with micropollutants

    Scalable Graph Embedding for Asymmetric Proximity

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    Graph Embedding methods are aimed at mapping each vertex into a low dimensional vector space, which preserves certain structural relationships among the vertices in the original graph. Recently, several works have been proposed to learn embeddings based on sampled paths from the graph, e.g., DeepWalk, Line, Node2Vec. However, their methods only preserve symmetric proximities, which could be insufficient in many applications, even the underlying graph is undirected. Besides, they lack of theoretical analysis of what exactly the relationships they preserve in their embedding space. In this paper, we propose an asymmetric proximity preserving (APP) graph embedding method via random walk with restart, which captures both asymmetric and high-order similarities between node pairs. We give theoretical analysis that our method implicitly preserves the Rooted PageRank score for any two vertices. We conduct extensive experiments on tasks of link prediction and node recommendation on open source datasets, as well as online recommendation services in Alibaba Group, in which the training graph has over 290 million vertices and 18 billion edges, showing our method to be highly scalable and effective

    Laser Interferometer for Space Gravitational Waves Detection and Earth Gravity Mapping

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    The idea of using space laser interferometer to measure the relative displacement change between two satellites has been considered for space gravitational waves detection and Earth gravity filed mapping in recent years. Some investigations on the key issues of laser interferometer in our working team have been presented in this paper. An on-ground laser interferometer prototype used for the demonstration of satellite-to-satellite ranging has been constructed, which is equipped with phasemeter, laser pointing modulation and laser phase-locking control. The experimental results show that path-length measurement sensitivity of the laser interferometer reaches 200 pm/ Hz, and phase measurement precision achieves 2 x 10(-5) rad/ Hz, and laser pointing modulation precision is better than 80 nrad/ Hz, and laser phase-locking control precision attains 2 x 10(-4) rad/ Hz within the frequency regime of 1 mHz-1 Hz. All of these demonstrate that the proposed laser interferometer has very promising feasibility to meet the requirement of the Taiji, TianQin and Space Advanced Gravity Measurement (SAGM) missions which are put forward by Chinese scientists

    The Degradation of Sulfamethoxazole via the Fe<sup>2+</sup>/Ultraviolet/Sodium Percarbonate Advanced Oxidation Process: Performance, Mechanism, and Back-Propagate–Artificial Neural Network Prediction Model

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    The degradation of sulfamethoxazole (SMX) via the Fe2+/Ultraviolet (UV)/sodium percarbonate (SPC) system was comprehensively investigated in this study, including the performance optimization, degradation mechanism, and predicting models. The degradation condition of SMX was optimized, and it was found that appropriate amounts of CFe2+ (10~30 μM) and CSPC (10 μM) under an acidic condition (pH = 4~6) were in favor of a higher degradation rate. According to probe compound experiments, it was considerable that ∙OH and ∙CO3− was the primary and subordinate free radical in SMX degradation, and k∙OH,SMX maintained two times more than that of k∙CO3−,SMX, especially under acidic conditions. The UV direct photolysis and other active intermediates were also responsible for the SMX degradation. These active intermediates were produced via the Fe2+/UV/SPC system, involving ∙HO2, HCO4−, ∙O2 −, or 1O2. Furthermore, when typical anions co-existed, the degradation of SMX was negatively influenced, owing to HCO3− and CO32− possibly consuming ∙OH or H2O2 to compete with SMX. In addition, the prediction model was successfully established via the back-propagate artificial neural network (BP-ANN) method. The degradation rate of SMX was well forecasted via the Back-Propagate–Artificial Neural Network (BP-ANN) model, which was expressed as Ypre=tanh(tanh(xiWih)Who). The BP-ANN model reflected the relative importance of influence factors well, which was pH > t > CFe2+≈CSPC. Compared to the response surface method Box–Behnken design (RSM-BBD) model (R2 = 0.9765, relative error = 3.08%), the BP-ANN model showed higher prediction accuracy (R2 = 0.9971) and lower error (1.17%) in SMX degradation via the Fe2+/UV/SPC system. These findings help us to understand, in-depth, the degradation mechanism of SMX; meanwhile, they are conducive to promoting the development of the Fe2+/UV/SPC system in SMX degradation, especially in some practical engineering cases

    Improved VIDAR and machine learning-based road obstacle detection method

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    There are various types of obstacles in an emergency, and the traffic environment is complicated. It is critical to detect obstacles accurately and quickly in order to improve traffic safety. The obstacle detection algorithm based on deep learning cannot detect all types of obstacles because it requires pre-training. The VIDAR (Vision-IMU-based Detection and Range method) can detect any three-dimensional obstacles, but at a slow rate. In this paper, an improved VIDAR and machine learning-based obstacle detection method (hereinafter referred to as the IVM) is proposed. In the proposed method, morphological closing operation and normalized cross-correlation are used to improve VIDAR. Then, the improved VIDAR is used to quickly match and remove the detected unknown types of obstacles in the image, and the machine learning algorithm is used to detect specific types of obstacles to increase the speed of detection with the average detection time of 0.316s. Finally, the VIDAR is used to detect regions belonging to unknown types of obstacles in the remaining regions, improving detection performance with the accuracy of 92.7%. The flow of the proposed method is illustrated by the indoor simulation test. Moreover, the results of outdoor real-world vehicle tests demonstrate that the method proposed in this paper can quickly detect obstacles in real-world environments and improve detection accuracy

    Robust trajectory tracking control for autonomous vehicle subject to velocity-varying and uncertain lateral disturbance

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    Autonomous vehicles are the most advanced intelligent vehicles and will play an important role in reducing traffic accidents, saving energy and reducing emission. Motion control for trajectory tracking is one of the core issues in the field of autonomous vehicle research. According to the characteristics of strong nonlinearity, uncertainty and changing longitudinal velocity for autonomous vehicles at high speed steering condition, the robust trajectory tracking control is studied. Firstly, the vehicle system models are established and the novel target longitudinal velocity planning is carried out. This velocity planning method can not only ensure that the autonomous vehicle operates in a strong nonlinear coupling state in bend, but also easy to be constructed. Then, taking the lateral location deviation minimizing to zero as the lateral control objective, a robust active disturbance rejection control path tracking controller is designed along with an extended state observer which can deal with the varying velocity and uncertain lateral disturbance effectively. Additionally, the feed for ward-feedback control method is adopted to control the total tire torque, which is distributed according to the steering characteristics of the vehicle for additional yaw moment to enhance vehicle handing stability. Finally, the robustness of the proposed controller is evaluated under velocity-varying condition and sudden lateral disturbance. The single-lane change maneuver and double-lane change maneuver under vary longitudinal velocity and different road adhesions are both simulated. The simulation results based on Matlab/Simulink show that the proposed controller can accurately observe the external disturbances and have good performance in trajectory tracking and handing stability. The maximum lateral error reduces by 0.18 meters compared with a vehicle that controlled by a feedback-feedforward path tracking controller in the single-lane change maneuver. The lateral deviation is still very small even in the double lane change case of abrupt curvature. It should be noted that our proposed control algorithm is simple and robust, thus provide great potential for engineering application

    Associations between ecological diversity and rodent plague circulation in Yunnan Province, China, 1983–2020: A data-informed modelling study

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    Background Following its resurgence in 1982, rodent plague has been linked to a wide range of circulation risks in Yunnan Province. The most serious public health concern associated with effective plague control is determining how various ecological variables influence the differential risk of transmission. Methods We investigated the population dynamics of the hosts and vectors using large-scale epidemiological surveillance data. In a seasonal eco-epidemiological model, we evaluated the impact of ecological conditions on the vectored flea index (VFI) to determine the rate of plague transmission. Results The findings revealed a changing species composition in natural foci over time. Additionally, shifting distributional ranges of species by elevation may be vital in modulating the VFI. The model estimates indicate that the dynamic VFI contributes to spatiotemporal variance in transmission. Conclusions The VFI could be a critical ecological indicator, allowing for real-time tracking and prompt intervention in the circulation of rodent plague. Understanding eco-epidemiological diversity can provide essential insights into effective responses to future plague resurgence. Author summary Plague have resurged among rodents in Yunnan Province since 1982, and intermittently occurs among humans. Yet the local risk of rodent plague dynamics has been highly diverse across ecological contexts. In natural foci, suggestions for this ecological diversity include high species richness and cyclic transmission between hosts and vectors. Here, we developed an eco-epidemiological framework to position the epidemiological dynamics of rodent plague in local ecological contexts. Our results suggest that diverse ecological conditions may have shaped the local risk of plague transmission in Yunnan Province. Typically, incremental of elevation has been associated with the tradeoff between the increased diversity and averted fraction of main host and vector species. More importantly, vectored flea index could be a critical ecological indicator for plague management
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