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An unsupervised learning approach to study synchroneity of past events in the South China Sea

Frontiers of Earth Science 2019年第3期13卷 628-640页

作者： Kevin C. Tse Hon-Chim Chiu man-yin tsang Yiliang Li Edmund Y. Lam Department of Earth Sciences The University of Hong KongPokfulamHong KongChina Department of Geography and Centre for Geo-computation Studies Hong Kong Baptist UniversityKowloon TongHong KongChina Department of Earth Sciences University of TorontoCanada Department of Electrical and Electronic Engineering The University of Hong KongPokfulamHong KongChina

Unsupervised machine learning methods were applied on multivariate geophysical and geochemical datasets of ocean floor sediment cores collected from the South China Sea. The well-preserved and continuous core samples comprising high resolution Cenozoic sediment records enable scientists to carry out paleoenvironment studies in detail. Bayesian age-depth chronological models constructed from biostratigraphic control points for the drilling sites are applied on cluster boundaries generated from two popular unsupervised learning methods: K-means and random forest. The unsupervised learning methods experimented have produced compact and unambiguous clusters from the datasets, indicating that previously unknown data patterns can be revealed when all variables from the datasets are taken into account simultaneously. A study of synchroneity of past events represented by the cluster boundaries across geographically separated ocean drilling sites is achieved through converting the fixed depths of cluster boundaries into chronological ranges represented by Gaussian density plots which are then compared with known past events in the region. A Gaussian density peak at around 7.2 Ma has been identified from results of all three sites and it is suggested to coincide with the initiation of the East Asian monsoon. Contrary to traditional statistical approach, a priori assumptions are not required for unsupervised learning, and the clustering results serve as a novel data-driven proxy for studying the complex and dynamic processes of the paleoenvironment surrounding the ocean sediment. This work serves as a pioneering approach to extract valuable information of regional events and opens up a systematic and objective way to study the vast global ocean sediment datasets.

关键词： machine learning ocean sediments unsupervised classification

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Unsupervised learning on scientific ocean drilling datasets from the South China Sea

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Frontiers of Earth Science 2019年第1期13卷 180-190页

作者： Kevin C.TSE Hon-Chim CHIU man-yin tsang Yiliang LI Edmund Y.LAM Department of Earth Sciences The University of Hong KongPokfulamHong KongChina Department of Geography and Centre for Geo-computation Studies Hong Kong Baptist UniversityKowloon TongHong KongChina Department of Earth Sciences University of TorontoTorontoON M5S 2M8Canada Department of Electrical and Electronic Engineering The University of Hong KongPokfulamHong KongChina

Unsupervised learning methods were applied to explore data patterns in multivariate geophysical datasets collected from ocean floor sediment core samples coming from scientific ocean drilling in the South China *** to studies on similar datasets,but using supervised learning methods which are designed to make predictions based on sample training data,unsupervised learning methods require no a priori information and focus only on the input *** this study,popular unsupervised learning methods including K-means,self-organizing maps,hierarchical clustering and random forest were coupled with different distance metrics to form exploratory data *** resulting data clusters were externally validated with lithologic units and geologic time scales assigned to the datasets by conventional methods. Compact and connected data clusters displayed varying degrees of correspondence with existing classification by lithologic units and geologic time scales.K-means and self-organizing maps were observed to perform better with lithologic units while random forest corresponded best with geologic time *** study sets a pioneering example of how unsupervised machine learning methods can be used as an automatic processing tool for the increasingly high volume of scientific ocean drilling data.

关键词： machine learning unsupervised learning ODP IODP clustering

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Indications of pro-inflammatory cytokines in laparoscopic and open liver resection for early-stage hepatocellular carcinoma

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Hepatobiliary & Pancreatic Diseases International 2024年第3期23卷 257-264页

作者： Kevin Tak-Pan Ng Li Pang Jia-Qi Wang Wong Hoi She Simon Hing-yin tsang Chung Mau Lo Kwan man Tan To Cheung Department of Surgery HKU-SZH&School of Clinical MedicineLi Ka Shing Faculty of MedicineThe University of Hong KongHong KongChina State Key Laboratory of Liver Research The University of Hong KongHong KongChina

Background:Our clinical practice of laparoscopic liver resection(LLR)had achieved better short-term and long-term benefits for patients with hepatocellular carcinoma(HCC)over open liver resection(OLR),but the underlying mechanisms are not *** study was to find out whether systemic inflammation plays an important ***:A total of 103 patients with early-stage HCC under liver resection were enrolled(LLR group,n=53;OLR group,n=50).The expression of 9 inflammatory cytokines in patients at preoperation,postoperative day 1(POD1)and POD7 was quantified by Luminex Multiplex *** relationships of the cytokines and the postoperative outcomes were compared between LLR and ***:Seven of the circulating cytokines were found to be significantly upregulated on POD1 after LLR or OLR compared to their preoperative *** to OLR,the POD1 levels of granulocytemacrophage colony-stimulating factor(GM-CSF),interleukin-6(IL-6),IL-8,and monocyte chemoattractant protein-1(MCP-1)in the LLR group were significantly *** POD1 levels of these cytokines were significantly correlated with longer operative time and higher volume of blood loss during *** levels of these cytokines were positively associated with postoperative liver injury,and the length of hospital ***,a high level of IL-6 at POD1 was a risk factor for HCC recurrence and poor disease-free survival after liver ***:Significantly lower level of GM-CSF,IL-6,IL-8,and MCP-1 after liver resection represented a milder systemic inflammation which might be an important mechanism to offer better short-term and long-term outcomes in LLR over OLR.

关键词： Laparoscopic liver resection Open liver resection Hepatocellular carcinoma Postoperative cytokines Inflammatory responses

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Immunoregulatory and Anti-cancer Activities of Combination Treatment of Novel Four-Herb Formula and Doxorubicin in 4T1-Breast Cancer Bearing Mice

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Chinese Journal of Integrative Medicine 2024年第4期30卷 311-321页

作者： Lea Ling-Yu Kan Ben Chung-Lap Chan Grace Gar-Lee Yue LI Pei-ting Sharon Sze-man Hon HUANG Dan-qi Miranda Sin-man tsang Clara Bik-San Lau Ping-Chung Leung Chun-Kwok Wong Institute of Chinese Medicine The Chinese University of Hong KongHong Kong SARChina State Key Laboratory of Research on Bioactivities and Clinical Applications of Medicinal Plants The Chinese University of Hong KongHong KongChina Department of Chemical Pathology The Chinese University of Hong KongHong Kong SARChina China-Australia International Research Centre for Chinese Medicine School of Health and Biomedical SciencesSTEM CollegeRMIT UniversityBundooraVictoriaAustralia Li Dak Sum Yip Yio Chin R&D Centre for Chinese Medicine The Chinese University of Hong Kong SARHong KongChina

Objective To investigate the in vivo immunomodulatory and anti-tumor mechanisms of the combined treatment of novel Four-Herb formula(4HF)and doxorubicin in triple-negative breast cancer(TNBC).Methods Murine-derived triple-negative mammary carcinoma cell line,4T1 cells,was cultured and inoculated into mouse mammary ***-six mice were randomly assigned into 6 groups(n=11 in ench):naive,control,LD 4HF(low dose 4HF),HD 4HF(high dose 4HF),LD 4HF+D(low dose and doxorubicin),and D(doxorubicin).Apart from the naive group,each mouse received subcutaneous inoculation with 5×10^(5)4T1 cells resuspended in 100µL of normal saline in the mammary fat *** from the day of tumor cell inoculation,tumors were grown for 6 *** LD and HD groups received daily oral gavage of 658 and 2,630 mg/kg 4HF,*** LD 4HF+D group received daily oral gavage of 658 mg/kg 4HF and weekly intraperitoneal injection of doxorubicin(5 mg/kg).The D group received weekly intraperitoneal injections of doxorubicin(5 mg/kg).The treatment naive mice received daily oral gavage of 0.2 mL double distilled water and 0.1 mL normal saline via intraperitoneal injection once a *** control group received daily oral gavage of 0.2 mL double-distilled *** treatment period was 30 *** the end of treatment,mice organs were harvested to analyze immunological activities via immunophenotyping,gene and multiplex analysis,histological staining,and gut microbiota *** Mice treated with the combination of 4HF and doxorubicin resulted in significantly reduced tumor and spleen burdens(Pmanipulated gut microbiota to favor the anti-tumor immunological ***,immunosuppressive genes,cytokines,and chemokines such as C-C motif chemokine 2 and interleukin-10 of tumors were significantly downregulated(P<0.05).4HF-doxorubicin combination treatment demonstrated synergetic activities and was most effective

关键词： adjunctivetherapy breast cancer cytokines Chinese medicine tumor microenvironment

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Recent progress on the Dirichlet divisor problem and the mean square of the Riemann zeta-function

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Science China Mathematics 2010年第9期53卷 2561-2572页

作者： tsang Kai-man Department of Mathematics The University of Hong Kong

Let Δ(x) and E(t) denote respectively the remainder terms in the Dirichlet divisor problem and the mean square formula for the Riemann zeta-function on the critical *** article is a survey of recent developments on the research of these famous error terms in number *** include upper bounds,Ω-results,sign changes,moments and distribution,etc.A few open problems are also discussed.

关键词： divisor problems Riemann’s zeta-function mean values

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Waring-Goldbach Problem for Unlike Powers

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Acta Mathematica Sinica,English Series 2007年第2期23卷 265-280页

作者： Xiu Min REN Kai man tsang Department of Mathematics Shandong University Department of Mathematics The University of Hong Kong

In this paper, it is proved that with at most O（N65/66） exceptions, all even positive integers up to N are expressible in the form p^2 2＋p^3 3＋p^4 4＋p^5 5. This improves a recent result O（N19193/19200＋ε） due... 详细信息

关键词： Waring-Goldbach problem circle method exceptional set

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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

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Arsenic Accumulation in Rice:Sources,Human Health Impact and Probable Mitigation Approaches

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Rice science 2022年第4期29卷 309-327页

作者： Md ROKONUZZAman LI Wai Chin man Yu Bon tsang Yiu Fai YE Zhihong Department of Science and Environmental Studies the Education University of Hong KongHong Kong 999077China School of Life Sciences Sun Yat-Sen UniversityGuangzhou 510006China

The human body loading with arsenic(As)through rice consumption is a global health *** is a crucial need to limit As build-up in rice,either by remediating As accumulation in soils or reducing As levels in irrigation *** conventional approaches have been utilized to alleviate the As accumulation in ***,except for some irrigation practices,those approaches success and the adoption rate are not *** review presents human health risks posed due to consumption of As contaminated rice,evaluates different biomarkers for tracing As loading in the human body,and discusses the latest advancement in As reducing technologies emphasizing the application of seed priming,nanotechnology,and biochar application for limiting As loading in rice *** also evaluate different irrigation techniques to reduce As accumulation in *** water management regimes significantly reduces grain As ***-and nano-priming of rice seeds improve germination and minimize As translocation in rice tissues by protecting cell membrane,building pool around seed coat,methylation and volatilization,or quenching harmful effects of reactive oxygen *** application in the form of nano-adsorbents or nano-fertilizers facilitates nano-remediation of As through the formation of Fe plaque or sorption or oxidation *** biochar in the rice fields significantly reduces As through immobilization,physical adsorption,or surface *** conclusion,As content in cooked rice depends on irrigation source and raw rice As level.

关键词： arsenic rice scalp hair irrigation management seed priming nanotechnology biochar human health

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MicroRNA-142-3p and microRNA-142-5p are downregulated in hepatocellular carcinoma and exhibit synergistic effects on cell motility

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Frontiers of Medicine 2015年第3期9卷 331-343页

作者： Felice Ho-Ching tsang Sandy Leung-Kuen Au Lai Wei Dorothy Ngo-yin Fan Joyce man-Fong Lee Carmen Chak-Lui Wong Irene Oi-Lin Ng Chun-Ming Wong State Key Laboratory for Liver Research and Department of Pathology Li Ka Shing Faculty of Medicine The University of Hong Kong HongKong SAR China

MicroRNAs （miRNAs）, an important class of small non-coding RNAs, regulate gene expression at the post-transcriptional level, miRNAs are involved in a wide range of biological processes and implicated in different diseases, including cancers. In this study, miRNA profiling and qRT-PCR validation revealed that miR-142-3p and miR-142-5p were significantly downregulated in hepatocellular carcinoma （HCC） and their expression levels decreased as the disease progressed. The ectopic expression of miR-142 significantly reduced HCC cell migration and invasion. Overexpression of either miR-142-3p or miR-142-5p suppressed HCC cell migration, and overexpression of both synergistically inhibited cell migration, which indicated that miR-142-3p and miR-142-5p may cooperatively regulate cell movement, miR-142-3p and miR-142-5p, which are mature miRNAs derived from the 3＇- and 5＇-strands of the precursor miR-142, target distinct pools of genes because of their different seed sequences. Pathway enrichment analysis showed a strong association of the putative gene targets of miR-142-3p and miR-142-5p with several cell motility-associated pathways, including those regulating actin cytoskeleton, adherens junctions, and focal adhesion. Importantly, a number of the putative gene targets were also significantly upregulated in human HCC cells. Moreover, overexpression of miR-142 significantly abrogated stress fiber formation in HCC cells and led to cell shrinkage. This study shows that mature miR-142 pairs collaboratively regulate different components of distinct signaling cascades and therefore affects the motility of HCC cells.

关键词： hepatocellular carcinoma microRNA metastasis cytoskeletal reorganization

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Spring Theory as an Approach to the Unification of Fields

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Journal of Modern Physics 2016年第15期7卷 2219-2230页

作者： Ling man tsang Fisica Laboratorio TIS Macao University of Science and Technology Macao China

The cosmological constant is necessary to be retained in Einstein’s field equations with value depending on the mass of the source. An overview of the spring theory in astrophysics and cosmology is included in this paper. In short range force, the two interacting particles are point-like vertices connected by a bosonic spring. We also suspect that electron may contain negative sterile neutrino. The self energy of a point charge is not infinite so that renormalisation is not necessary.

关键词： Cosmological Constant Dark Matter Classical Electrostatics Short Range Interaction

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