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Qian Wu,Mengmeng Yu,Yuehua Li,Wenbin Li,Zhigang Lu,Meng Wei,Jing Yan,Jiayin Zhang 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.2
Objective: To investigate the morphological changes of coronary chronic total occlusion (CTO) as determined by coronary computed tomography angiography (CCTA) follow-up using semi-automated quantitative analysis. Materials and Methods: Thirty patients with 31 CTO lesions confirmed by invasive coronary angiography and baseline/follow-up CCTA were retrospectively included. CTOs were quantitatively analyzed by a semi-automated coronary plaque analysis software (Coronary Plaque Analysis, version 2.0, Siemens) after manually determining the lesion border. Recanalized lumen was defined as the linear-like enhanced opacity traversing the non-opacified occluded segment. Other parameters, such as total occlusion length, total occlusion volume, volume with low attenuation component (< 30 Hounsfield unit [HU]), volume with middle to high attenuation component (30−190 HU) as well as the calcification volume, were also recorded. Results: Recanalized lumen was found within 48.4% (15/31) occlusions on the follow-up CCTA, compared to 45.2% (14/31) occlusions on the baseline CCTA. Eleven of 14 lesions (78.6%) with CT-visible recanalized lumen within CTOs had a shorter occlusion length on follow-up compared to only 3 of 17 lesions (17.6%) without CT-visible recanalized lumen (odds ratio, 17.1, p < 0.001). The percentage of low attenuation component of occlusions was smaller on follow-up CCTA compared to baseline value (18.1 ± 20.1% vs. 22.6 ± 19.6%, p = 0.033). Conclusion: Coronary computed tomography angiography enables non-invasive characterization of natural progression of untreated CTO lesions. Recanalized lumen within CTOs observed at baseline CCTA was associated with shortening of occlusion length on follow-up. Compared to their earlier stage, occlusions of later stage were presented with higher density of non-calcified components.
A self-normalization test for a change-point in the shape parameter of a gamma distributed sequence
Changchun Tan,Yuehua Wu,Cuiling Dong,Baiqi Miao 한국통계학회 2013 Journal of the Korean Statistical Society Vol.42 No.3
In this paper, a parametric change-point problem encountered in analyzing a gamma distributed sequence is considered. We propose a self-normalization based CUSUM type test statistic to detect the presence of a change-point, and obtain its limiting null distribution. The CUSUM-based procedure for detecting the location of this change-point is also given. At the same time, simulation results are provided, which show that our procedures are effective.
Tan Changchun,Hu Junying,Wu Yuehua 한국통계학회 2021 Journal of the Korean Statistical Society Vol.50 No.1
In this paper, the multiple change-point problem in the scale parameter of a sequence of independent gamma distributed observations is discussed. A reversible jump Markov chain Monte Carlo (RJMCMC) algorithm is developed to compute the posterior probabilities of the number and positions of the multiple change-points. Four types of jumps are designed, and the acceptance probability of each type is given. The simulation studies show that the RJMCMC-based method is efcient in the detection of multiple change-points in the scale parameter in gamma distributed sequence, and performs better than a self-normalization based method. In addition, a real data example about successive rises and falls of Shanghai stock exchange composite index yield is used to illustrate the proposed methodology
Effects of a chitosan nanoparticles encapsulation on the properties of litchi polyphenols
Xingan Cheng,Qiwen Zou,Hanhui Zhang,Jianwei Zhu,Murtaza Hasan,Fangyun Dong,Xin Liu,Junjie Li,Yuehua Wu,Xiaojing Lv,Keqiang Wang,Xiangling Deng,Zhanmei Liu,Xuhong Jiang 한국식품과학회 2023 Food Science and Biotechnology Vol.32 No.13
Litchi polyphenols have very specific biological activities. Nevertheless, the low and inconsistent oral bioavailability and instability hinder the further application of litchi polyphenols in food systems. This work prepared litchi polyphenols loaded chitosan nanoparticles (LP-CSNPs) by ionic gelation method to enhance the encapsulation on the properties of litchi polyphenols. The optimum conditions of formation via single factors and the Box–Behnken design were chitosan (CS) concentration 1.065 mg/mL, sodium tripolyphosphate (TPP) concentration 0.975 mg/mL, and the mass ratios of polyphenols and CS 1:1 with encapsulation efficiency (EE%) of 45.53%. LP-CSNPs presented the nanosized range of particle size (mean 170 nm), excellent polydispersity index (PDI) (0.156 ± 0.025), and zeta potential values (+ 35.44 ± 0.59). The in vitro release in simulated gastric fluid (pH 1.2) and intestinal fluid (pH 6.8) during 100 h was 58.34% and 81.68%, respectively. LP-CSNPs could effectively improve the storage stability and had great antibacterial activity compared with unencapsulated litchi polyphenols.