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Impact of effective stress on permeability for carbonate fractured-vuggy rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 942-960页

作者： Ke Sun Huiqing Liu Juliana y.leung Jing Wang yabin Feng Renjie Liu Zhijiang Kang yun Zhang State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China School of Mining&Petroleum Engineering University of AlbertaEdmontonT6G 1H9Canada SINOPEC Petroleum Exploration and Production Research Institute Beijing100083China

to gain insight into the flow mechanisms and stress sensitivity for fractured-vuggy reservoirs,several core models with different structural characteristics were designed and fabricated to investigate the impact of effective stress on permeability for carbonate fractured-vuggy rocks(CFVR).It shows that the permeability performance curves under different pore and confining pressures(*** stress conditions)for the fractured core models and the vuggy core models have similar change *** ranges of permeability variation are significantly wider at high pore pressures,indicating that permeability reduction is the most significant during the early stage of development for fractured-vuggy *** each obtained effective stress coefficient for permeability(ESCP)varies with the changes in confining pressure and pore pressure,the effective stresses for permeability of four representative CFVR show obvious nonlinear characteristics,and the variation ranges of ESCP are all between 0 and ***,a comprehensive ESCP mathematical model considering triple media,including matrix pores,fractures,and dissolved vugs,was *** is proved theoretically that the ESCP of CFVR generally varies between 0 and ***,the regression results showed that the power model ranked highest among the four empirical models mainly applied in stress sensitivity characterization,followed by the logarithmic model,exponential model,and binomial *** concept of“permeability decline rate”was introduced to better evaluate the stress sensitivity performance for CFVR,in which the one-fracture rock is the strongest,followed by the fracture-vug rock and two-horizontalfracture rock;the through-hole rock is the *** general,this study provides a theoretical basis to guide the design of development and adjustment programs for carbonate fractured-vuggy reservoirs.

关键词： Effective stress Permeability Carbonate fractured-vuggy rocks Structure characteristics Stress sensitivity

Quantitative and qualitative subgenomic RNA profiles of SARS-CoV-2 in respiratory samples: A comparison between Omicron BA.2 and non-VOC-D614G

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Virologica Sinica 2024年第2期39卷 218-227页

作者： Zigui Chen Rita Way yin Ng Grace Lui Lowell Ling Agnes S.y.leung Chit Chow Siaw Shi Boon Wendy C.S.Ho Maggie Haitian Wang Renee Wan yi Chan Albert Martin Li David Shu Cheong Hui Paul Kay Sheung Chan Department of Microbiology Faculty of MedicineThe Chinese University of Hong KongHong KongChina Department of Medicine and therapeutics Faculty of MedicineThe Chinese University of Hong KongHong KongChina Department of Anaesthesia and Intensive Care Faculty of MedicineThe Chinese University of Hong KongHong KongChina Department of Paediatrics Faculty of MedicineThe Chinese University of Hong KongHong KongChina Department of Anatomical and Cellular Pathology Faculty of MedicineThe Chinese University of Hong KongHong KongChina Jockey Club School of Public Health and Primary Care Faculty of MedicineThe Chinese University of Hong KongHong KongChina Stanley Ho Centre for Emerging Infectious Diseases Faculty of MedicineThe Chinese University of Hong KongHong KongChina

the SARS-CoV-2 Omicron variants are notorious for their transmissibility,but little is known about their subgenomic RNA(sgRNA)*** study applied RNA-seq to delineate the quantitative and qualitative profiles of canonical sgRNA of 118 respiratory samples collected from patients infected with Omicron BA.2 and compared with 338 patients infected with non-variant of concern(non-VOC)-D614G.A unique characteristic profile depicted by the relative abundance of 9 canonical sgRNAs was reproduced by both BA.2 and non-VOCD614G regardless of host gender,age and presence of ***,such profile was lost in samples with low viral load,suggesting a potential application of sgRNA pattern to indicate viral activity of individual patient at a specific time point.A characteristic qualitative profile of canonical sgRNAs was also reproduced by both BA.2 and *** presence of a full set of canonical sgRNAs carried a coherent correlation with crude viral load(AUC¼0.91,95%CI 0.88–0.94),and sgRNA ORF7b was identified to be the best surrogate marker allowing feasible routine application in characterizing the infection status of individual *** potentials in using sgRNA as a target for vaccine and antiviral development are worth pursuing.

关键词： Coronavirus SARS-CoV-2 Omicron BA.2 Non-VOC-D614G RNA-seq Subgenomic RNA(sgRNA)

Chemical biology investigation of a triple-action,smart-decomposition antimicrobial booster based-combination therapy against“ESKAPE”pathogens

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Science China Chemistry 2024年第9期67卷 3071-3082页

作者： Min Wang Huangsheng Pu yangfan Xu Chenxuan Wu yuanxin Gu Qingyun Cai Guoxing yin Peng yin Chunhui Zhang Wing-leung Wong Muyang Wan yugang Bai Xinxin Feng State Key Laboratory of Chem-/Bio-Sensing and Chemometrics Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biologyand School of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China College of Biology Hunan UniversityChangsha 410082China College of Advanced Interdisciplinary Studies&Hunan Provincial Key Laboratory of Novel Nano Optoelectronic Information Materials and Devices National University of Defense TechnologyChangsha 410073China Nanhu Laser Laboratory National University of Defense TechnologyChangsha 410073China Key Laboratory of Chemical Biology and traditional Chinese Medicine Research(Ministry of Education) College of Chemistry and Chemical EngineeringHunan Normal UniversityChangsha 410081China State Key Laboratory of Chemical Biology and Drug Discovery Department of Applied Biology and Chemical TechnologyThe Hong Kong Polytechnic UniversityHong Kong SAR 999077China Hunan Provincial Key Laboratory of Anti-Resistance Microbial Drugs The Third Hospital of Changsha(The Affiliated Changsha Hospital of Hunan University)Changsha 410015China

the global antibiotic resistance crisis necessitates urgent *** innovative approach involves potentiating antibiotics and non-antibiotic drugs with adjuvants or boosters.A major drawback of these membrane-active boosters is their limited biocompatibility,as they struggle to differentiate between proka.y.tic and euka.y.tic *** study reports the chemical biology investigation of a dual-action oligoamidine(OA1)booster with a glutathione-triggered decomposition ***1,when combined with other antimicrobial molecules,exhibits a triple-targeting mechanism including cell membrane disruption,DNA targeting,and intracellular enzyme *** multi-targeting mechanism not only enhances the in vitro and in vivo eradication of antibiotic-resistant“ESKAPE”pathogens,but also suppresses the development of bacterial ***,OA1 maintains its activity in bacterial cells by creating an oxidative environment,while it quickly decomposes in mammalian cells due to high glutathione *** mechanistic insights and design principles may provide a feasible approach to develop novel antimicrobial agents and effective anti-resistance combination therapies.

关键词： antimicrobial booster oligoamidine membrane disruption DNA targeting triggered degradation anti-resistance

Superior antibody and membrane protein‑specific t‑cell responses to CoronaVac by intradermal versus intramuscular routes in adolescents

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World Journal of Pediatrics 2024年第4期20卷 353-370页

作者： Jaime S.Rosa Duque Samuel M.S.Cheng Carolyn A.Cohen Daniel leung Xiwei Wang Xiaofeng Mu yuet Chung tsun Ming Lau Manni Wang Wenyue Zhang yanmei Zhang Howard H.W.Wong Leo C.H.tsang Sara Chaothai tsz Chun Kwan John K.C.Li Karl C.K.Chan Leo L.H.Luk Jenson C.H.Ho Wing yan Li Amos M.t.Lee Jennifer H.y.Lam Sau Man Chan Wilfred H.S.Wong Issan y.S.tam Masashi Mori Sophie A.Valkenburg Malik Peiris Wenwei tu yu Lung Lau Department of Paediatrics and Adolescent Medicine The University of Hong KongHong KongChina School of Public Health The University of Hong KongHong KongChina HKU‑Pasteur Research Pole School of Public HealthThe University of Hong KongHong KongChina Research Institute for Bioresources and Biotechnology Ishikawa Prefectural UniversityNonoichiJapan Department of Microbiology and Immunology Peter Doherty Institute for Infectionand ImmunityUniversity of MelbourneMelbourneVICAustralia Center for Immunology and Infection C2i Hong KongChina

Background Optimising the immunogenicity of COVID-19 vaccines to improve their protection against disease is *** dosing by intradermal(ID)administration has been shown to be equally immunogenic as intramuscular(IM)administration for several vaccines,but the immunogenicity of ID inactivated whole severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)at the full dose is *** study(NCt04800133)investigated the superiority of antibody and t-cell responses of full-dose CoronaVac by ID over IM administration in *** Participants aged 11–17 years received two doses of IM or ID vaccine,followed by the 3rd dose 13–42 days *** and cellular immunogenicity outcomes were measured post-dose 2(IM-CC versus ID-CC)and post-dose 3(IMCCC versus ID-CCC).Doses 2 and 3 were administered to 173 and 104 adolescents,*** Spike protein(S)immunoglobulin G(IgG),S-receptor-binding domain(RBD)IgG,S IgG Fcγreceptor IIIa(FcγRIIIa)-binding,SNM[sum of individual(S),nucleocapsid protein(N),and membrane protein(M)peptide pool]-specific interleukin-2(IL-2)+CD4^(+),SNM-specific IL-2^(+)CD8^(+),S-specific IL-2^(+)CD8^(+),N-specific IL-2^(+)CD4^(+),N-specific IL-2^(+)CD8^(+)and M-specific IL-2^(+)CD4^(+)responses fulfilled the superior and non-inferior criteria for ID-CC compared to IM-CC,whereas IgG avidity was *** ID-CCC,S-RBD IgG,surrogate virus neutralisation test,90%plaque reduction neutralisation titre(PRNt90),PRNt50,S IgG avidity,S IgG FcγRIIIa-binding,M-specific IL-2^(+)CD4^(+),interferon-γ+CD8^(+)and IL-2^(+)CD8^(+)responses were superior and non-inferior to *** estimated vaccine efficacies were 49%,52%,66%and 79%for IM-CC,ID-CC,IM-CCC and ID-CCC,*** ID groups reported more local,mild adverse *** this is the first study to demonstrate superior antibody and M-specific t-cell responses by ID inactivated SARSCoV-2 vaccination and serves as the basis for future research to improve the

关键词： CoronaVac Coronavirus disease 2019 Immunity Intradermal Vaccine

Dynamic stiffness for thin-walled structures by power series

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第8期7卷 1351-1357页

作者： ZHU Bin leung a.y.t. Department of Civil Engineering Zhejiang University Hangzhou 310027 China Department of Building and Construction City University of Hong Kong Hong Kong China

the dynamic stiffness method is introduced to analyze thin-walled structures including thin-walled straight beams and spatial twisted helix beam. A dynamic stiffness matrix is formed by using frequency dependent shape functions which are exact solutions of the governing differential equations. With the obtained thin-walled beam dynamic stiffness matrices, the thin-walled frame dynamic stiffness matrix can also be formulated by satisfying the required displacements compatibility and forces equilib-rium, a method which is similar to the finite element method (FEM). then the thin-walled structure natural frequencies can be found by equating the determinant of the system dynamic stiffness matrix to zero. By this way, just one element and several elements can exactly predict many modes of a thin-walled beam and a spatial thin-walled frame, respectively. Several cases are studied and the results are compared with the existing solutions of other methods. the natural frequencies and buckling loads of these thin-walled structures are computed.

关键词： Dynamic stiffness method thin-wall structures Power series Buckling

Solution procedure of residue harmonic balance method and its applications

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Science China(Physics,Mechanics & Astronomy) 2014年第8期57卷 1581-1591页

作者： GUO ZhongJin leung a.y.t MA Xiaoyan School of Mathematics and Statistics Taishan University Department of Civil and Architectural Engineering City University of Hong Kong

this paper presents a simple and rigorous solution procedure of residue harmonic balance for predicting the accurate approximation of certain autonomous ordinary differential *** this solution procedure,no small parameter is *** harmonic residue of balance equation is separated in two parts at each *** first part has the same number of Fourier terms as the present order of approximation and the remaining part is used in the subsequent *** corrections are governed by linear ordinary differential equation so that they can be solved easily by means of harmonic balance method *** kinds of different differential equations involving general,fractional and delay ordinary differential systems are given as numerical examples *** accurate limited cycle frequency and amplitude are *** results match well with the exact solutions or numerical solutions for a wide range of control *** with those available shows that the residue harmonic balance solution procedure is very effective for these autonomous differential ***,the present method works not only in predicting the amplitude but also the frequency of bifurcated period solution for delay ordinary differential equation.

关键词： residue harmonic balance accurate approximation fractional ordinary differential system delay ordinary differential system

Genomics-driven derivatization of the bioactive fungal sesterterpenoid variecolin:Creation of an unnatural analogue with improved anticancer properties

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Acta Pharmaceutica Sinica B 2024年第1期14卷 421-432页

作者： Dexiu yan Jemma Arakelyan teng Wan Ritvik Raina tsz Ki Chan Dohyun Ahn Vladimir Kushnarev tsz Kiu Cheung Ho Ching Chan Inseo Choi Pui yi Ho Feijun Hu yujeong Kim Hill Lam Lau ying Lo Law Chi Seng leung Chun yin tong Kai Kap Wong Wing Lam yim Nikolay S.Karnaukhov Richard y.C.Kong Maria V.Babak yudai Matsuda Department of Chemistry City University of Hong KongHong Kong SARChina iGEM team“VarieCure” City University of Hong KongHong Kong SARChina Department of Biomedical Engineering City University of Hong KongHong Kong SARChina Moscow Clinical Research Center Named After A.S.Loginov Moscow 111123Russian Federation

A biosynthetic gene cluster for the bioactive fungal sesterterpenoids variecolin(1)and variecolactone(2)was identified in Aspergillus aculeatus AtCC *** production of 1 and 2 was achieved in Aspergillus oryzae by expressing the sesterterpene synthase VrcA and the cytochrome P450 ***,the replacement of VrcB with homologous P450s from other fungal terpenoid pathways yielded three new variecolin analogues(5-7).Analysis of the compounds’anticancer activity in vitro and in vivo revealed that although 5 and 1 had comparable activities,5 was associated with significantly reduced toxic side effects in cancer-bearing mice,indicating its potentially broader therapeutic *** study describes the first tests of variecolin and its analogues in animals and demonstrates the utility of synthetic biology for creating molecules with improved biological activities.

关键词： Animal studies Anticancer properties Biosynthesis Natural products Sesterterpenoids Synthetic biology terpene synthases Variecolin

tHE EVALUAtION OF StRESS INtENSIty FACtORS OF PLANE CRACK FOR ORtHOtROPIC PLAtE WItH EQUAL PARAMEtER By F2LFEM

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Acta Mechanica Solida Sinica 2006年第2期19卷 128-134页

作者： Fan Jie Zhang Xiaochun a.y.t. leung Zhong Weifang Department of Mechanics Huazhong University of Science and Technology Wuhan 430074 China Department of Building and Construction City University of Hong Kong Hong Kong China

In this paper, the evaluation of stress intensity factor of plane crack problems for orthotropic plate of equal-parameter is investigated using a fractal two-level finite element method （F2LFEM）. the general solution of an orthotropic crack problem is obtained by assimilating the problem with isotropic crack problem, and is employed as the global interpolation function in F2LFEM. In the neighborhood of crack tip of the crack plate, the fractal geometry concept is introduced to achieve the similar meshes having similarity ratio less than one and generate an infinitesimal mesh so that the relationship between the stiffness matrices of two adjacent layers is equal. A large number of degrees of freedom around the crack tip are transformed to a small set of generalized coordinates. Numerical examples show that this method is efficient and accurate in evaluating the stress intensity factor （SIF）.

关键词： plane crack orthotropic plate fractal finite element stress intensity factor

Study on the wind field and pollutant dispersion in street canyons using a stable numerical method

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Journal of Environmental Sciences 2005年第3期17卷 488-490页

作者： Dennis y.C. leung Department of Mechanical Engineering the University of Hong Kong Hong Kong China

A stable finite element method for the time dependent Navier-Stokes equations was used for studying the wind flow and pollutant dispersion within street canyons. A three-step fractional method was used to solve the velocity field and the pressure field separately from the governing equations. the Streamline Upwind Petrov-Galerkin(SUPG) method was used to get stable numerical results. Numerical oscillation was minimized and satisfactory results can be obtained for flows at high Reynolds numbers. Simulating the flow over a square cylinder within a wide range of Reynolds numbers validates the wind field model. the Strouhal numbers obtained from the numerical simulation had a good agreement with those obtained from experiment. the wind field model developed in the present study is applied to simulate more complex flow phenomena in street canyons with two different building configurations. the results indicated that the flow at rooftop of buildings might not be assumed parallel to the ground as some numerical modelers did. A counter-clockwise rotating vortex may be found in street canyons with an inflow from the left to right. In addition, increasing building height can increase velocity fluctuations in the street canyon under certain circumstances, which facilitate pollutant dispersion. At high Reynolds numbers, the flow regimes in street canyons do not change with inflow velocity.

关键词： finite element method Streamline Upwind Petrov-Galerkin method three-step fractional method