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1. chinaXiv:202109.00058 [pdf]

Dating the First Case of COVID-19 Epidemic from a Probabilistic Perspective

Zhouwang Yang; Yunhe Hu; Zhiwei Ding; Tiande Guo
Subjects: Mathematics >> Applied Mathematics

In the early days of the epidemic of coronavirus disease 2019 (COVID-19), due to insufficient knowledge of the pandemic, inadequate nucleic acid tests, lack of timely data reporting, etc., the origin time of the onset of COVID-19 is difficult to determine. Therefore, source tracing is crucial for infectious disease prevention and control. The purpose of this paper is to infer the origin time of pandemic of COVID-19 based on a data and model hybrid driven method. We model the testing positive rate to fit its actual trend, and use the least squares estimation to obtain the optimal model parameters. Further, the kernel density estimation is applied to infer the origin time of pandemic given the specific confidence probability. By selecting 12 representative regions in the United States for analysis, the dates of the first infected case with 50% confidence probability are mostly between August and October 2019, which are earlier than the officially announced date of the first confirmed case in the United States on January 20, 2020. The experimental results indicate that the COVID-19 pandemic in the United States starts to spread around September 2019 with a high confidence probability. In addition, the existing confirmed cases are also used in Wuhan City and Zhejiang Province in China to infer the origin time of COVID-19 and provide the confidence probability. The results show that the spread of COVID-19 pandemic in China is likely to begin in late December 2019.

submitted time 2021-09-22 Hits26006Downloads4582 Comment 0

2. chinaXiv:201705.00715 [pdf]

Dynamic Balance of pSTAT1 and pSTAT3 in C57BL/6 Mice Infected with Lethal or Nonlethal Plasmodium yoelii

Xibao Shi; Li Qin; Guangjie Liu; Siting Zhao; Nanzheng Peng; and Xiaoping Chen
Subjects: Biology >> Biomedical Laboratory Science

Signal transducer and activator of transcription (STAT) proteins play an important role in cytokine signaling pathways and regulation of immune responses. The balance of the phosphorylated (activated) STAT1 (pSTAT1) and STAT3 (pSTAT3) has been documented in cancer immunology. In this study, we investigated the dynamic balance of pSTAT1 and pSTAT3 in C57BL/6 mice infected with either a nonlethal (Py17XNL) or lethal (Py17XL) strain of Plasmodium yoelii. Both Py17XNL and Py17XL infections induced a maximum activation of STAT1 and STAT3 on the first day after parasite inoculation. Additionally, the Py17XNL infection induced a pSTAT1-dominant response in mice during the early stage of infection, with the resolution of parasitemia. In contrast, Py17XL infection induced a pSTAT3-dominant response during the early phase of infection, with the death of the animals. Our results indicated that maximum activation of STAT1 and STAT3 occurred much earlier than the peak levels of cytokines induced by Plasmodium yoelii infection based on previous reports and that infection with Py17XNL and Py17XL induced different dynamic patterns of pSTAT1 and pSTAT3 balance. Cellular & Molecular Immunology

submitted time 2017-05-10 Hits2346Downloads845 Comment 0

3. chinaXiv:201705.00711 [pdf]

Esrrb Activates Oct4 Transcription and Sustains Self-renewal and Pluripotency in Embryonic Stem Cells

Xiaofei Zhang(1); Juan Zhang(2); Tao Wang(3); Miguel A. Esteban(3); Duanqing Pei(4)
Subjects: Biology >> Biomedical Laboratory Science

The genetic program of embryonic stem (ES) cells is orchestrated by a core of transcription factors that has OCT4, SOX2, and NANOG as master regulators. Protein levels of these core factors are tightly controlled by autoregulatory and feed-forward transcriptional mechanisms in order to prevent early differentiation. Recent studies have shown that knockdown of Esrrb (estrogen-related-receptor beta), a member of the nuclear orphan receptor family, induces differentiation of mouse ES cells cultured in the presence of leukemia inhibitory factor. It was however not known how knocking down Esrrb exerts this effect. Herein we have identified two ESRRB binding sites in the proximal 5'-untranslated region of the mouse Oct4 gene, one of which is in close proximity to a NANOG binding site. Both ESRRB and NANOG are necessary for maintaining the activity of this promoter in ES cell lines. We have also demonstrated that the two transcription factors interact through their DNA binding domains. This interaction reciprocally modulates their transcriptional activities and may be important to fine-tune ES cell pluripotency. Supporting all of these data, stable transfection of Esrrb in ES cell lines proved sufficient to sustain their characteristics in the absence of leukemia-inhibitory factor. In summary, our experiments help to understand how Esrrb coordinates with Nanog and Oct4 to activate the internal machinery of ES cells.

submitted time 2017-05-10 Hits1942Downloads1007 Comment 0

4. chinaXiv:201609.00971 [pdf]

Concept for a Future Super Proton-Proton Collider

Jingyu Tang; J. Scott Berg; Weiping Chai; Fusan Chen; Nian Chen; Weiren Chou; HaiyiDong; Jie Gao; Tao Han; Yongbin Leng; Guangrui Li; Ramesh Gupta; Peng Li; Zhihui Li; Baiqi Liu; Yudong Liu; Xinchou Lou; Qing Luo; Ernie Malamud; Lijun Mao
Subjects: Physics >> Nuclear Physics

Following the discovery of the Higgs boson at LHC, new large colliders are being studied by the international high-energy community to explore Higgs physics in detail and new physics beyond the Standard Model. In China, a two-stage circular collider project CEPC-SPPC is proposed, with the first stage CEPC (Circular Electron Positron Collier, a so-called Higgs factory) focused on Higgs physics, and the second stage SPPC (Super Proton-Proton Collider) focused on new physics beyond the Standard Model. This paper discusses this second stage.

submitted time 2016-09-14 Hits1050Downloads619 Comment 0

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