388 research outputs found

    Topological superfluid in a fermionic bilayer optical lattice

    Full text link
    In this paper, a topological superfluid phase with Chern number C=1 possessing gapless edge states and non-Abelian anyons is designed in a C=1 topological insulator proximity to an s-wave superfluid on an optical lattice with the effective gauge field and layer-dependent Zeeman field coupled to ultracold fermionic atoms pseudo spin. We also study its topological properties and calculate the phase stiffness by using the random-phase-approximation approach. Finally we derive the temperature of the Kosterlitz-Thouless transition by means of renormalized group theory. Owning to the existence of non-Abelian anyons, this C=1 topological superfluid may be a possible candidate for topological quantum computation.Comment: 15 pages, 8 figure

    Incidence and recurrence of acute otitis media in Taiwan's pediatric population

    Get PDF
    OBJECTIVE: To report the incidence and recurrence of acute otitis media (AOM) in Taiwan's pediatric population. METHODS: Information from children (aged <= 12 years) with a diagnosis of AOM was retrieved from the 2006 National Healthcare Insurance claims database. We calculated the cumulative incidence rate and the incidence density rate of recurrent AOM within one year after the initial diagnosis in 2006. We used a multivariate logistic regression model to assess the predictors for recurrence of AOM. RESULTS: The annual incidence rate of AOM was estimated to be 64.5 cases per 1,000 children. The overall one-year cumulative incidence rate of recurrence was 33.1%, and the incidence density rate was 33.5 cases per 100 personyears, with the highest figure (41.2 cases per 100 person-years) noted for children aged 0-2 years. Recurrence was significantly associated with age, gender, place of treatment, and physician specialty. CONCLUSION: AOM remains a major threat to children's health in Taiwan. Male children and very young children require more aggressive preventive strategies to reduce the risk of recurrence

    Interfacial Properties of Polyethylene Glycol/Vinyltriethoxysilane (PEG/VTES) Copolymers and their Application to Stain Resistance

    Get PDF
    In this study, polyethylene glycol (PEG) and vinyltriethoxysilane (VTES) were used in different proportions to produce a series of PEG–VTES copolymers. The copolymer molecular structures were confirmed by FTIR spectroscopy. In addition, their surface activities were evaluated by evaluating the surface tension, contact angle, and foaming properties. The results showed that these surfactants exhibited excellent surface activities and wetting power, as well as low foaming. Consequently, the application of a series of PEG/VTES copolymers can make cotton fabrics stain resistant

    High-throughput Automated Muropeptide Analysis (HAMA) Reveals Peptidoglycan Composition of Gut Microbial Cell Walls

    Get PDF
    Peptidoglycan (PGN), a net-like polymer constituted by muropeptides, provides protection for microorganisms and has been a major target for antibiotics for decades. Researchers have explored host-microbiome interactions through PGN recognition systems and discovered key muropeptides modulating host responses. However, most common characterization techniques for muropeptides are labor-intensive and require manual analysis of mass spectra due to the complex cross-linked PGN structures. Each species has unique moiety modifications and inter-/intra-bridges, which further complicates the structural analysis of PGN. Here, we developed a high-throughput automated muropeptide analysis (HAMA) platform leveraging tandem mass spectrometry and in silico muropeptide MS/MS fragmentation matching to comprehensively identify muropeptide structures, quantify their abundance, and infer PGN cross-linking types. We demonstrated the effectiveness of HAMA platform using well-characterized PGNs from E. coli and S. aureus and further applied it to common gut bacteria including Bifidobacterium, Bacteroides, Lactobacillus, Enterococcus, and Akkermansia muciiniphila. Specifically, we found that the stiffness and strength of the cell envelopes may correspond to the lengths and compositions of interpeptide bridges within Bifidobacterium species. In summary, the HAMA framework exhibits an automated, intuitive, and accurate analysis of PGN compositions, which may serve as a potential tool to investigate the post-synthetic modifications of saccharides, the variation in interpeptide bridges, and the types of cross-linking within bacterial PGNs.</p

    Automated Classification Model With OTSU and CNN Method for Premature Ventricular Contraction Detection

    Get PDF
    Premature ventricular contraction (PVC) is one of the most common arrhythmias which can cause palpitation, cardiac arrest, and other symptoms affecting the work and rest activities of a patient. However, patients hardly decipher their own feelings to determine the severity of the disease thus, requiring a professional medical diagnosis. This study proposes a novel method based on image processing and convolutional neural network (CNN) to extract electrocardiography (ECG) curves from scanned ECG images derived from clinical ECG reports, and segment and classify heartbeats in the absence of a digital ECG data. The ECG curve is extracted using a comprehensive algorithm that combines the OTSU algorithm with erosion and dilation. This algorithm can efficiently and accurately separate the ECG curve from the ECG background grid. The performance of the classification model was evaluated and optimized using hundreds of clinical ECG data collected from Fujian Provincial Hospital. Additionally, thousands of clinical ECG reports were scanned to digital images as the test set to confirm the accuracy of the algorithm for practical application. Results showed that the average sensitivity, specificity, positive predictive value, and accuracy of the proposed model on the MIT-BIH dataset were 95.47%, 97.72%, 98.75%, and 98.25%, respectively. The classification average sensitivity, specificity, positive predictive value, and accuracy based on clinical scanned ECG images can reach to 97.24%, 81.6%, 83.8%, and 89.33%, respectively, and the clinical feasibility is high. Overall, the proposed method can extract ECG curves from scanned ECG images efficiently and accurately. Furthermore, it performs well on heartbeat classification of normal (N) and ventricular premature heartbeat

    Genome Mining of the Marine Actinomycete Streptomyces sp. DUT11 and Discovery of Tunicamycins as Anti-complement Agents

    Get PDF
    Marine actinobacteria are potential producers of various secondary metabolites with diverse bioactivities. Among various bioactive compounds, anti-complement agents have received great interest for drug discovery to treat numerous diseases caused by inappropriate activation of the human complement system. However, marine streptomycetes producing anti-complement agents are still poorly explored. In this study, a marine-derived strain Streptomyces sp. DUT11 showing superior anti-complement activity was focused, and its genome sequence was analyzed. Gene clusters showing high similarities to that of tunicamycin and nonactin were identified, and their corresponding metabolites were also detected. Subsequently, tunicamycin I, V, and VII were isolated from Streptomyces sp. DUT11. Anti-complement assay showed that tunicamycin I, V, VII inhibited complement activation through the classic pathway, whereas no anti-complement activity of nonactin was detected. This is the first time that tunicamycins are reported to have such activity. In addition, genome analysis indicates that Streptomyces sp. DUT11 has the potential to produce novel lassopeptides and lantibiotics. These results suggest that marine Streptomyces are rich sources of anti-complement agents for drug discovery

    SIRT1 Activation by a c-MYC Oncogenic Network Promotes the Maintenance and Drug Resistance of Human FLT3-ITD Acute Myeloid Leukemia Stem Cells

    Get PDF
    SummaryThe FLT3-ITD mutation is frequently observed in acute myeloid leukemia (AML) and is associated with poor prognosis. In such patients, FLT3 tyrosine kinase inhibitors (TKIs) are only partially effective and do not eliminate the leukemia stem cells (LSCs) that are assumed to be the source of treatment failure. Here, we show that the NAD-dependent SIRT1 deacetylase is selectively overexpressed in primary human FLT3-ITD AML LSCs. This SIRT1 overexpression is related to enhanced expression of the USP22 deubiquitinase induced by c-MYC, leading to reduced SIRT1 ubiquitination and enhanced stability. Inhibition of SIRT1 expression or activity reduced the growth of FLT3-ITD AML LSCs and significantly enhanced TKI-mediated killing of the cells. Therefore, these results identify a c-MYC-related network that enhances SIRT1 protein expression in human FLT3-ITD AML LSCs and contributes to their maintenance. Inhibition of this oncogenic network could be an attractive approach for targeting FLT3-ITD AML LSCs to improve treatment outcomes

    S1PR1 regulates ovarian cancer cell senescence through the PDK1-LATS1/2-YAP pathway

    Get PDF
    Cell senescence deters the activation of various oncogenes. Induction of senescence is, therefore, a potentially effective strategy to interfere with vital processes in tumor cells. Sphingosine-1-phosphate receptor 1 (S1PR1) has been implicated in various cancer types, including ovarian cancer. The mechanism by which S1PR1 regulates ovarian cancer cell senescence is currently elusive. In this study, we demonstrate that S1PR1 was highly expressed in human ovarian cancer tissues and cell lines. S1PR1 deletion inhibited the proliferation and migration of ovarian cancer cells. S1PR1 deletion promoted ovarian cancer cell senescence and sensitized ovarian cancer cells to cisplatin chemotherapy. Exposure of ovarian cancer cells to sphingosine-1-phosphate (S1P) increased the expression of 3-phosphatidylinositol-dependent protein kinase 1 (PDK1), decreased the expression of large tumor suppressor 1/2 (LATS1/2), and induced phosphorylation of Yes-associated protein (p-YAP). Opposite results were obtained in S1PR1 knockout cells following pharmacological inhibition. After silencing LATS1/2 in S1PR1-deficient ovarian cancer cells, senescence was suppressed and S1PR1 expression was increased concomitantly with YAP expression. Transcriptional regulation of S1PR1 by YAP was confirmed by chromatin immunoprecipitation. Accordingly, the S1PR1-PDK1-LATS1/2-YAP pathway regulates ovarian cancer cell senescence and does so through a YAP-mediated feedback loop. S1PR1 constitutes a druggable target for the induction of senescence in ovarian cancer cells. Pharmacological intervention in the S1PR1-PDK1-LATS1/2-YAP signaling axis may augment the efficacy of standard chemotherapy.</p

    Decision Support System for the Response to Infectious Disease Emergencies Based on WebGIS and Mobile Services in China

    Get PDF
    Background: For years, emerging infectious diseases have appeared worldwide and threatened the health of people. The emergence and spread of an infectious-disease outbreak are usually unforeseen, and have the features of suddenness and uncertainty. Timely understanding of basic information in the field, and the collection and analysis of epidemiological information, is helpful in making rapid decisions and responding to an infectious-disease emergency. Therefore, it is necessary to have an unobstructed channel and convenient tool for the collection and analysis of epidemiologic information in the field. Methodology/Principal Findings: Baseline information for each county in mainland China was collected and a database was established by geo-coding information on a digital map of county boundaries throughout the country. Google Maps was used to display geographic information and to conduct calculations related to maps, and the 3G wireless network was used to transmit information collected in the field to the server. This study established a decision support system for the response to infectious-disease emergencies based on WebGIS and mobile services (DSSRIDE). The DSSRIDE provides functions including data collection, communication and analyses in real time, epidemiological detection, the provision of customized epidemiological questionnaires and guides for handling infectious disease emergencies, and the querying of professional knowledge in the field. These functions of the DSSRIDE could be helpful for epidemiological investigations in the field and the handling of infectious-disease emergencies. Conclusions/Significance: The DSSRIDE provides a geographic information platform based on the Google Maps application programming interface to display information of infectious disease emergencies, and transfers information between workers in the field and decision makers through wireless transmission based on personal computers, mobile phones and personal digital assistants. After a 2-year practice and application in infectious disease emergencies, the DSSRIDE is becoming a useful platform and is a useful tool for investigations in the field carried out by response sections and individuals. The system is suitable for use in developing countries and low-income districts
    • 

    corecore