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Your search keyword '"Peng, Zhihang"' showing total 290 results
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290 results on '"Peng, Zhihang"'

22. Studying the impacts of variant evolution for a generalized age-group transmission model.

Author

Wei, Fengying, Zhou, Ruiyang, Jin, Zhen, Sun, Yamin, Peng, Zhihang, Cai, Shaojian, Chen, Guangmin, and Zheng, Kuicheng

Subjects
SARS-CoV-2 Delta variant, SARS-CoV-2 Omicron variant, BASIC reproduction number, SARS-CoV-2, COVID-19 pandemic
Abstract

The differences of SARS-CoV-2 variants brought the changes of transmission characteristics and clinical manifestations during the prevalence of COVID-19. In order to explore the evolution mechanisms of SARS-CoV-2 variants and the impacts of variant evolution, the classic SIR (Susceptible-Infected-Recovered) compartment model was modified to a generalized SVEIR (Susceptible-Vaccinated-Exposed-Infected-Recovered) compartment model with age-group and varying variants in this study. By using of the SVEIR model and least squares method, the optimal fittings against the surveillance data from Fujian Provincial Center for Disease Control and Prevention were performed for the five epidemics of Fujian Province. The main epidemiological characteristics such as basic reproduction number, effective reproduction number, sensitivity analysis, and cross-variant scenario investigations were extensively investigated during dynamic zero-COVID policy. The study results showed that the infectivities of the variants became fast from wild strain to the Delta variant, further to the Omicron variant. Meanwhile, the cross-variant investigations showed that the average incubation periods were shortened, and that the infection scales quickly enhanced. Further, the risk estimations with the new variants were performed without implements of the non-pharmaceutical interventions, based on the dominant variants XBB.1.9.1 and EG.5. The results of the risk estimations suggested that non-pharmaceutical interventions were necessary on the Chinese mainland for controlling severe infections and deaths, and also that the regular variant monitors were still workable against the aggressive variant evolution and the emergency of new transmission risks in the future. [ABSTRACT FROM AUTHOR]

Published
2024
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23. Modeling the Nonmonotonic Immune Response in a Tumor–Immune System Interaction.

Author

Liu, Yu, Ma, Yuhang, Yang, Cuihong, Peng, Zhihang, Takeuchi, Yasuhiro, Banerjee, Malay, and Dong, Yueping

Subjects
IMMUNE response, HOPF bifurcations, ORBITS (Astronomy), IMMUNE system, CELL physiology
Abstract

Tumor–immune system interactions are very complicated, being highly nonlinear and not well understood. A large number of tumors can potentially weaken the immune system through various mechanisms such as secreting cytokines that suppress the immune response. In this paper, we propose a tumor–immune system interaction model with a nonmonotonic immune response function and adoptive cellular immunotherapy (ACI). The model has a tumor-free equilibrium and at most three tumor-presence equilibria (low, moderate and high ones). The stability of all equilibria is studied by analyzing their characteristic equations. The consideration of nonmonotonic immune response results in a series of bifurcations such as the saddle-node bifurcation, transcritical bifurcation, Hopf bifurcation and Bogdanov–Takens bifurcation. In addition, numerical simulation results show the coexistence of periodic orbits and homoclinic orbits. Interestingly, along with various bifurcations, we also found two bistable scenarios: the coexistence of a stable tumor-free as well as a high-tumor-presence equilibrium and the coexistence of a stable-low as well as a high-tumor-presence equilibrium, which can show symmetric and antisymmetric properties in a range of model parameters and initial cell concentrations. The new findings indicate that under ACI, patients can possibly reach either a stable tumor-free state or a low-tumor-presence state in the presence of nonmonotonic immune response once the immune system is activated. [ABSTRACT FROM AUTHOR]

Published
2024
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26. Estimating the time interval between transmission generations and the presymptomatic period by contact tracing surveillance data from 31 provinces in the mainland of China

Author

Ding, Zhongxing, Wang, Kai, Shen, Mingwang, Zhao, Shi, Song, Wenyu, Li, Rui, Li, Zhongjie, Wang, Liping, Feng, Ganzhu, Hu, Zhiliang, Wei, Hongxia, Xiao, Yanni, Bao, Changjun, Hu, Jianli, Zhu, Liguo, Li, Yong, Chen, Xufeng, Yin, Yi, Wang, Weiming, Cai, Yongli, Peng, Zhihang, and Shen, Hongbing

Published
2021
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28. Impact of interventions on the incidence of natural focal diseases during the outbreak of COVID-19 in Jiangsu Province, China

Author

Cheng, Xiaoqing, Hu, Jianli, Luo, Li, Zhao, Zeyu, Zhang, Nan, Hannah, Mikah Ngwanguong, Rui, Jia, Lin, Shengnan, Zhu, Yuanzhao, Wang, Yao, Yang, Meng, Xu, Jingwen, Liu, Xingchun, Yang, Tianlong, Liu, Weikang, Li, Peihua, Deng, Bin, Li, Zhuoyang, Liu, Chan, Huang, Jiefeng, Peng, Zhihang, Bao, Changjun, and Chen, Tianmu

Published
2021
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44. Environmental Contamination of SARS-CoV-2 Delta VOC by COVID-19 Patients Staying in the Hospital for More Than Two Weeks.

Author

Ge, Jingwu, Zhang, Chuanmeng, Peng, Zhihang, Chu, Minjuan, Chen, Wensen, Li, Zhanjie, Liu, Shuangyuan, Yang, Yongfeng, and Chu, Ming

Subjects
COVID-19, SARS-CoV-2, SARS-CoV-2 Delta variant, COVID-19 pandemic, HOSPITAL patients
Abstract

Background: Patients infected with SARS-CoV-2 Delta VOC have a longer course of disease. We detected the air, surfaces, and patient's personal items in the wards of the second hospital of Nanjing during the outbreak of the COVID-19 Delta Variant to identify the environmental contamination, which provides a theoretical basis for the prevention and control of COVID-19 variation beads in the future.Methods: In the cross-sectional study, we collected and analyzed clinical features, demographic and epidemiological data, laboratory and swab test results, and surface and air samples of 144 COVID-19 cases.Results: The time from symptom onset to surface sampling was 25 days (IQR, 21 to 33 days). Positive throat swabs were detected in 52(36.1%) patients, of which only 8(5.6%) patients had N or ORF1a/b genes Ct value < 35 on the surface sampling day. Among the 692 environmental surface and air specimens collected from 144 COVID-19 cases, 3 specimens (3/692, 0.4%) related to 5 cases (3.5%, 5/144) were detected positive on RT-PCR. Overall, bedside tables (2/144, 1.4%) were most likely to be contaminated, followed by toilet seats (1/81, 1.2%).Conclusion: The environmental contamination by SARS-CoV-2 Delta VOC-infected cases with disease duration of more than two weeks is limited. [ABSTRACT FROM AUTHOR]

Published
2023
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