1,720,974 research outputs found
CUHK electronic theses & dissertations collection
No full textby Gary Wing-Kin Wong."July 1999."Thesis (M.D.)--Chinese University of Hong Kong, 1999.Includes bibliographical references (p. 174-198).Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.Mode of access: World Wide Web
Cheng xiang er tong xiao chuan fa bing de huan jing ying xiang
No full textPh.D.Introduction: Asthma is one of the most common chronic diseases affecting children and its prevalence has been increasing gradually over the past few decades. One of the most consistent findings is that the prevalence of childhood asthma and allergies in rural areas is much lower than that of urban cities. In our initial screening of 17,587 children aged 5-8 years from Hong Kong (urban) and Conghua (rural southern China), asthma and allergies were 2-3 times more prevalent in Hong Kong. In particular, exposure to domestic poultry was most closely associated with the lower prevalence of asthma in the rural environment.Objectives: Studies presented in this thesis aimed to: (1) characterise the immune profiles of urban and rural children; (2) verify the allergy-protective effect of domestic poultry exposure; (3) determine underlying mechanisms of the rural protection against asthma; (4) delineate the role of respiratory viral infections in asthma development.Methods: A case-control study was conducted to characterise the immune profiles of children from rural Conghua and urban Hong Kong. Peripheral blood mononuclear cells were extracted for the measurement of gene expression and cytokine secretion under different stimulation conditions. Environmental dust samples were collected from rural families with domestic poultry and biological activities of aqueous dust extracts were assessed both in vitro and in vivo using polarised human bronchial epithelial (16HBE14o-) cell line and ovalbumin (OVA)-induced asthma model of BALB/c mice. In addition, we conducted a prospective study of urban children hospitalised for asthma and other wheezing disorders. Nasopharyngeal aspirates were obtained for the detection of respiratory viruses through immunofluorescence and multiplex PCR testing.Results: At baseline, rural control subjects exhibited lower cytokine production and gene expression of multiple immune molecules compared with their urban counterparts. Ex vivo stimulation substantially induced regulatory T-cell numbers, cytokine secretion and gene expression of a variety of immune markers, with higher amplitude in rural children compared with those in urban children. There was a dose- and time-dependent increase in transepithelial electrical resistance of epithelial cells stimulated with dust extracts from rural homes with poultry. Compared with mice received OVA alone, mice treated with farm dust extracts showed significantly decreased proportion of eosinophils (22.85% vs. 59.2%, p< 0.05) and increased percentage of neutrophils (18.15% vs. 5.4%, p< 0.05) in bronchoalveolar lavage fluid. Intranasal administration with farm dust extracts strongly inhibited gene expression of Th2 signature cytokines IL-5 (p= 0.01) and IL-13 (p< 0.05), while induced IL-17 (p< 0.05) in vivo. Furthermore, the majority of urban children hospitalised for asthma and wheezing illnesses had a viral infection, with rhinovirus being the most frequently detected respiratory virus.Conclusions: Exposure to domestic poultry conferred asthma protection in the rural environment. Rural children had downregulated immune responses likely induced by constant microbial exposures. Among urban children, the majority of asthma and wheezing disorders resulting in hospitalisation were associated with respiratory viral infections. These findings represent a novel explanation of the rural protection against the development of childhood asthma and provide a direction in the search for potential preventative strategies.研究背景：哮喘是兒童期最常見的慢性疾病之一，其發病率近幾十年來逐年上升。目前最一致的研究发现是，農村地區兒童哮喘及過敏性疾病患病率遠低於城鎮兒童。在對來自香港（城市）和從化縣（中國南部鄉郊）总计17,587 名五至八歲學齡前兒童的初步篩查中，發現香港市區哮喘及過敏性疾病的發病率是農村的2 至3 倍。特別的是，在農村地區，接觸家禽與低哮喘發病率強相關。研究目的：本研究旨在：（1）描述農村與城市兒童免疫學指標的差異；（2）進一步驗證家禽接觸的過敏防護作用；（3）探究农村环境对哮喘的保护作用的机理；（4）了解呼吸道病毒感染在哮喘发展中的作用。研究方法：为明確從化農村兒童與香港市區兒童免疫譜的差異，我們開展了病例對照研究。提取的外周血單核細胞用於不同刺激條件下基因表達和細胞因子分泌的評估。此外，我們收集了農村家庭的雞舍粉塵樣本，並使用極化的人支氣管上皮細胞（16HBE14o-）細胞系和卵清蛋白（OVA）誘導的BALB/c 小鼠哮喘模型評估水溶性粉塵提取物的體外及體內生物學活性。此外，對因哮喘及喘息性疾病收入威爾士親王醫院的兒童患者進行了前瞻性隨訪研究。對城市兒童患者的鼻咽抽吸物進行了免疫熒光和多重聚合酶鏈式反应檢測，以明確病毒病因學。研究結果：在基線水平，農村兒童細胞因子分泌和多種免疫分子的基因表達均低於城市兒童。離體刺激大幅增加了調節性T 細胞數量和多種免疫分子的基因表達。相較城市兒童，該變化在農村兒童中更為顯著。以農村雞舍粉塵提取物刺激的上皮細胞，其跨上皮電阻呈劑量和時間依賴性增加。與僅接受OVA 的小鼠相較，鼻内滴注農村雞舍灰塵提取物的小鼠支氣管肺泡灌洗液中嗜酸性粒細胞比例顯著降低（22.85％ vs. 59.2％，p< 0.05），而中性粒細胞百分比显著增加（18.15％ vs. 5.4％，p< 0.05）。此外，鼻內滴注農村雞舍粉塵提取物強烈抑制小鼠肺組織Th2 細胞應答的標誌性細胞因子IL-5（p= 0.01）和IL-13（p< 0.05）基因的表達，同時誘導IL-17 的表達（p< 0.05）。大多數因喘息性疾病入院的城市兒童存在呼吸道感染，且以鼻病毒感染為最為常見。研究結論：接觸家禽與農村的哮喘保護作用強相關。農村兒童的免疫反應因受持續微生物暴露的影響而呈現耐受性。城市兒童中，導致住院的哮喘及喘息性疾病大多與呼吸道病毒感染有關。此研究從新穎的角度闡釋了農村環境對兒童哮喘的保護機制，並為今後預防策略的制定指明了方向。Xing, Yuhan.Thesis Ph.D. Chinese University of Hong Kong 2020.Includes bibliographical references (leaves 179-205).Abstracts also in Chinese; appendix includes Chinese.Title from PDF title page (viewed on April 4, 2022).Xing, Yuhan
Tan tao du shi he nong cun xue ling er tong zhi jian xiao chuan fa bing lu de cha ju
No full textWong, Lau Yi.Thesis M.Phil. Chinese University of Hong Kong 2015.Includes bibliographical references (leaves 130-171).Abstracts and appendix 1 also in Chinese.Title from PDF title page (viewed on 31, October, 2016).Wong, Lau Yi
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
