173 research outputs found
A Spread Willingness Computing-Based Information Dissemination Model
This paper constructs a kind of spread willingness computing based on information dissemination model for social network. The model takes into account the impact of node degree and dissemination mechanism, combined with the complex network theory and dynamics of infectious diseases, and further establishes the dynamical evolution equations. Equations characterize the evolutionary relationship between different types of nodes with time. The spread willingness computing contains three factors which have impact on user’s spread behavior: strength of the relationship between the nodes, views identity, and frequency of contact. Simulation results show that different degrees of nodes show the same trend in the network, and even if the degree of node is very small, there is likelihood of a large area of information dissemination. The weaker the relationship between nodes, the higher probability of views selection and the higher the frequency of contact with information so that information spreads rapidly and leads to a wide range of dissemination. As the dissemination probability and immune probability change, the speed of information dissemination is also changing accordingly. The studies meet social networking features and can help to master the behavior of users and understand and analyze characteristics of information dissemination in social network
Quantum Efficiency and Lifetime Study for Negative Electron Affinity GaAs Nanopillar Array Photocathode
Recent studies showed significant improvement in quantum efficiency (QE) by negative electron affinity (NEA) GaAs nanopillar array (NPA) photocathodes over their flat surface peers, particularly at 500 ─ 800 nm waveband. However, the underlying physics is yet to be well understood for further improvement in its performance. In this report, NEA GaAs NPA photocathodes with different dimensions were studied. The diameter of the nanopillars varied from 200 ─ 360 nm, the height varied from 230 ─ 1000 nm and the periodicity varied from 470 ─ 630 nm. The QE and photocathode lifetime were measured. Mie-resonance enhancement was observed at tunable resonance wavelengths. Simulations was also performed to understand the mechanism of photo-absorption and possible ways to further improve the photocathode performance to meet the stringent requirement of the electron sources in large scale electron accelerators
Antibiotic resistance of Helicobacter pylori in Nanjing, China: a cross-section study from 2018 to 2023
BackgroundThe increasing prevalence of antibiotic resistance in cases of Helicobacter pylori (H. pylori) infection has emerged as a significant global issue. This study offers a comprehensive examination of the alterations in drug resistance exhibited by H. pylori in the Nanjing region of China during the preceding five years. Another important objective is to investigate the influence of levofloxacin medication history on genotypic and phenotypic resistance.MethodsThis research screened 4277 individuals diagnosed with H. pylori infection between April 2018 and May 2023. The phenotype and genotypic resistance were evaluated using the Kirby-Bauer disk diffusion and PCR method.ResultsThe most recent primary resistance rates for metronidazole, clarithromycin, levofloxacin, amoxicillin, furazolidone, and tetracycline were recorded at 77.23% (2385/3088), 37.24% (1150/3088), 27.72% (856/3088), 0.52% (16/3088), 0.19% (6/3088), and 0.06% (2/3088), respectively. For the recent five years, we observed a notable upsurge in the rate of metronidazole resistance and a slight elevation of clarithromycin and levofloxacin resistance. The documented resistance rates to single-drug, dual-drug, triple-drug, and quadruple-drug regimens were 35.39%, 28.32%, 25.72%, and 0.21%, respectively. The prevalence of multidrug-resistant strains escalated, rising from 37.96% in 2018 to 66.22% in 2023. The rate of phenotypic and genotypic resistance rate (57.10% and 65.57%) observed in strains obtained from patients without a levofloxacin treatment history was significantly lower than the rate in strains obtained from those with a history of levofloxacin treatment (88.73% and 94.74%). The prevailing gyrA mutations were primarily N87K (52.35%, 345/659), accompanied by D91N (13.96%, 92/659), and closely followed by D87G (10.77%, 71/659). For gyrA mutations, the 91-amino acid mutants exhibit a higher likelihood of discrepancies between phenotypic and genotypic resistance than the 87-amino acid mutants.ConclusionThe extent of antibiotic resistance within H. pylori remains substantial within the Nanjing region. If levofloxacin proves ineffective in eradicating H. pylori during the initial treatment, its use in subsequent treatments is discouraged. The employment of levofloxacin resistance genotype testing can partially substitute conventional antibiotic sensitivity testing. Notably, predicting phenotypic resistance of levofloxacin through PCR requires more attention to the mutation type of gyrA to improve prediction accuracy
Temperature and strain rate dependence of microstructural evolution and dynamic mechanical behavior in nanocrystalline Ti
The mechanical behavior of commercial purity titanium with a nanocrystalline (NC) grain size was investigated using split Hopkinson pressure bar tests at high strain rates and over a range of temperatures. The study was accompanied by detailed microstructural investigations before and after compression testing. The results show that rotary dynamic recrystallization operates during compressive deformation at strain rates of ~3000 and ~4500 s?1 at temperatures from 298 to 573 K but cells form at 673 K. The dynamic mechanical behavior of NC Ti shows a strong dependence on temperature and strain rate such that the flow stress and the strain hardening rate both increase with increasing strain and decreasing temperature. A constitutive equation is derived to relate the flow stress to the temperature, strain rate and true strain and to predict the yield strength and the peak stress of NC Ti subjected to dynamic deformation at elevated temperatures
Analysis of risk factors of recurrence in non-muscle invasive bladder cancer patients after initial transurethral resection of bladder tumor
Background and purpose: The recurrence rate of non-muscle invasive bladder cancer (NMIBC) after transurethral resection of bladder tumor (TURBT) is high. There are few studies on the risk factors of recurrence in NMIBC patients after initial TURBT. Our study aimed to screen the high-risk population and take corresponding preventive intervention measures by analyzing the risk factors of recurrence in NMIBC patients after initial TURBT. Methods: A total of 197 NMIBC patients who received initial TURBT in The Cancer Hospital of the University of Electronic Science and Technology of China from December 2015 to May 2020 were selected and followed up for 24 to 77 months. Patients were divided into recurrence group (48 cases) and non-recurrence group (149 cases) according to the results. Univariate analysis was performed on the clinical data of the two groups, and the indicators with statistical significance were included in the multivariate logistic regression analysis to screen the possible risk factors of recurrence. Results: Univariate analysis showed that the difference was statistically significant between two groups in gross hematuria, secondary resection, T1 stage, high grade tumor, multiple tumor and lack of immediate intravesical therapy (P <0.05).There was no significant difference in gender, age, family history of tumor, smoking history, tumor size and subsequent intravesical therapy between two groups (P>0.05). The receiver operating characteristic (ROC) curves of the ratio of neutrophils to lymphocytes and the ratio of neutrophils and hemoglobin to lymphocytes showed no statistically significant difference between two groups (P>0.05). Multivariate logistic regression analysis showed that T1 stage, high grade tumor, multiple tumor and lack of immediate intravesical therapy were independent risk factors of recurrence in NMIBC patients after initial TURBT (P<0.05, OR > 1). Conclusion: The recurrence of NMIBC patients after initial TURBT is closely related to tumor stage, tumor grade, tumor number and immediate intravesical therapy. Corresponding intervention measures can be taken to reduce the postoperative recurrence rate in initial NMIBC patients
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