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111 results on '"Guo, Si"'

24. Enzymatic preparation of pyruvate by a whole-cell biocatalyst coexpressing l-lactate oxidase and catalase

Author

Hai-Long Xue, Guo-Si Li, Mianbin Wu, Jianping Lin, Lirong Yang, Yiqi Jiang, and Jiazhang Lian

Subjects
0106 biological sciences, chemistry.chemical_classification, 0303 health sciences, Oxidase test, biology, Substrate (chemistry), Bioengineering, Oxidative phosphorylation, medicine.disease_cause, 01 natural sciences, Applied Microbiology and Biotechnology, Biochemistry, 03 medical and health sciences, Transformation (genetics), Enzyme, chemistry, Catalase, 010608 biotechnology, Yield (chemistry), biology.protein, medicine, Escherichia coli, 030304 developmental biology
Abstract

Enzymatic oxidative dehydrogenation of biomass-derived l -lactate in the presence of O2 is regarded as a green alternative for pyruvate production, but the process also results in H2O2 accumulation. To remove the effect of H2O2 on pyruvate production, various potential catalases from different species were screened for their efficiency in H2O2 degradation. Then, an in vitro cascade biocatalysis was designed using lactate oxidase from Aerococcus viridans (AvLOX) and catalase from Ureibacillus thermosphaericus (UtCAT). The in situ removal of H2O2 by UtCAT significantly improved the yield and productivity of pyruvate. To simplify the technological processes and reduce production costs, a whole cell biocatalyst without the addition of catalase for the production of pyruvate was established by coexpressing AvLOX and UtCAT in Escherichia coli. By applying suitable coexpression strategies and changing the ribosome binding site (RBS) strengths, the optimal ratio of AvLOX:UtCAT(12.6:4127.3) in E. coli-AvLOX-(rbs3)UtCAT was finally achieved. Under the optimized transformation conditions, pyruvate was produced at a titer of 59.9 g/L and a yield of 90.8% in a substrate fed-batch process, promising an alternative route for the green production of pyruvate.

Published
2020

31. A molecular computing approach to solving optimization problems via programmable microdroplet arrays

Author

Guo, Si Yue, primary, Friederich, Pascal, additional, Cao, Yudong, additional, Wu, Tony C., additional, Forman, Christopher J., additional, Mendoza, Douglas, additional, Degroote, Matthias, additional, Cavell, Andrew, additional, Krasecki, Veronica, additional, Hickman, Riley J., additional, Sharma, Abhishek, additional, Cronin, Leroy, additional, Gianneschi, Nathan, additional, Goldsmith, Randall H., additional, and Aspuru-Guzik, Alán, additional

Published
2021
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37. Comparison of different samples for 2019 novel coronavirus detection by nucleic acid amplification tests

Author

Guo Huang, Li Jiang, Bo Gong, Bo Long, Lingxi Jiang, Chunbao Xie, He Lin, Zhenglin Yang, Xingxiang Yang, Xuemei Chen, Yi Shi, H.J. Yu, Guo Si, Shi Ma, and Hong Pu

Subjects
0301 basic medicine, Microbiology (medical), Oropharyngeal swab, China, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), 030106 microbiology, Pneumonia, Viral, Urine, Virus, lcsh:Infectious and parasitic diseases, 03 medical and health sciences, Betacoronavirus, Feces, Young Adult, 0302 clinical medicine, Medicine, Nucleic Acid Amplification Tests, Humans, lcsh:RC109-216, 030212 general & internal medicine, Pandemics, business.industry, SARS-CoV-2, COVID-19, Nucleic acid amplification technique, General Medicine, medicine.disease, Virology, Pneumonia, Blood, Infectious Diseases, Nucleic acid, Pharynx, Female, business, Coronavirus Infections, Nucleic Acid Amplification Techniques
Abstract

An ongoing outbreak of severe respiratory pneumonia associated with the 2019 novel coronavirus has recently emerged in China. Here we report the epidemiological, clinical, laboratory and radiological characteristics of 19 suspect cases. We compared the positive ratio of 2019-nCoV nucleic acid amplification test results from different samples including oropharyngeal swab, blood, urine and stool with 3 different fluorescent RT-PCR kits. Nine out of the 19 patients had 2019-nCoV infection detected using oropharyngeal swab samples, and the virus nucleic acid was also detected in eight of these nine patients using stool samples. None of positive results was identified in the blood and urine samples. These three different kits got the same result for each sample and the positive ratio of nucleic acid detection for 2019-nCoV was only 47.4% in the suspect patients. Therefore, it is possible that infected patients have been missed by using nucleic acid detection only. It might be better to make a diagnosis combining the computed tomography scans and nucleic acid detection. Keywords: 2019 Novel coronavirus pneumonia, Clinical diagnosis, Nucleic acid amplification test

Published
2020
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38. Central-edge asymmetry as a probe of Higgs-top coupling in tt¯h production at the LHC

Author

Jinmian Li, Lei Wu, Zong-Guo Si, and Jason Tsz Shing Yue

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, media_common.quotation_subject, Elementary particle, Coupling (probability), 01 natural sciences, Asymmetry, Standard Model, Nuclear physics, 0103 physical sciences, Higgs boson, Grand Unified Theory, CP violation, 010306 general physics, Boson, media_common
Abstract

The Higgs-top coupling plays a central role in the hierarchy problem and the vacuum stability of the Standard Model (SM). We propose a central-edge asymmetry ( A C E ) to probe the CP violating Higgs-top coupling in dileptonic channel of t t ¯ h ( → b b ¯ ) production at the LHC. We demonstrate that the CP-violating Higgs-top coupling can affect the central-edge asymmetry through distorting Δ y l + l − distribution because of the contribution of new top charge asymmetric term. Since Δ y l + l − distribution is frame-independent and has a good discrimination even in boosted regime, we use the jet substructure technique to enhance the observability of the dileptonic channel of t t ¯ h production. We find that (1) the significance of dileptonic channel of t t ¯ h production can reach 5 σ for CP phase ξ = 0 , π / 4 , π / 2 when the luminosity L = 795 , 993 , 1276 fb − 1 at 14 TeV LHC. (2) the central-edge asymmetry A C E show a good discrimination power of CP phase of t t ¯ h interaction, which are − 40.26 % , − 26.60 % , − 9.47 % for ξ = 0 , π / 4 , π / 2 respectively and are hardly affected by the event selections. Besides, by performing the binned- χ 2 analysis of Δ y l + l − distribution, we find that the scalar and pseudo-scalar interactions can be distinguished at 95% C.L. level at 14 TeV HL-LHC.

Published
2018

49. B→πℓ+ℓ− form factors reexamined in the whole kinematically accessible region

Author

Zuo-Hong Li, Zong-Guo Si, Nan Zhu, and Y. G. Wang

Subjects
Physics, Nuclear and High Energy Physics, Quantum mechanics, Light cone, Momentum transfer, Lattice QCD, Symmetry breaking, Sum rule in quantum mechanics, Ansatz, Mathematical physics
Abstract

We reexamine the B → π l + l − ( l = e , μ , τ ) form factors, f + B → π ( q 2 ) , f 0 B → π ( q 2 ) and f T B → π ( q 2 ) , in the entire region of the momentum transfer squared q 2 , by taking advantage of the complementarity between lattice QCD (LQCD) simulation and light cone sum rule approach (LCSR), and analyticity of the form factors. A LCSR calculation with a chiral current correlator, which could avoid pollution by twist-3 components, is performed at twist-2 next-to-leading order (NLO) accuracy, to determinate the form factor shapes in the small and intermediate q 2 region. Further, fitting simultaneously the LCSR results for these form factors and the related LQCD ones (available or based on a SU F ( 3 ) symmetry breaking ansatz) to a Bourrely–Caprini–Lellouch (BCL) parametrization, we get a global understanding of their q 2 behaviors. Our findings turn out to be consistent with the recent study by Ali, Parkhomenko and Rusov, and the resulting observation for the vector form factor provides support for the existing LQCD as well as LCSR predictions extrapolated to the entire kinematically accessible region.

Published
2015

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