• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14429
  • 10946
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 4556
  • 3245
  • 3244
  • 980
  • 976
  • 889
  • 749
  • 721
  • 695
  • 680
  • 652
  • 616
  • 565
  • 561
  • 543
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Genetic predisposition to Alzheimer's disease: studies by linkage and hypothesis-driven candidate gene approach. / CUHK electronic theses & dissertations collection

January 2006 (has links)
Alzheimer's disease (AD) is the most common form of dementia, currently affecting around 17--25 million people worldwide. The typical neuropathological hallmarks of AD are amyloid beta (Abeta) deposition, presence of neurofibrillary tangles and neuronal cell death. Evidence from ongoing studies on the pathogenesis of AD, suggests that several different mechanisms are involved in neurons loss and thus decline of cognitive function. These include the metabolism of amyloid peptide, inflammation, cholesterol metabolism, and hormonal factors. / I have focused on the role of inflammation in the progression of AD. The inflammation hypothesis is based on findings of (1) elevated levels of inflammatory cytokines, such as IL-1, IL-6, TNFalpha, (2) the reduced levels of anti-inflammatory cytokines, like IL-10 in CSF and the blood of AD patients, and (3) activated microglia in the histological section of the patient's brain. On the other hand, the effects of the ApoE gene and differential age of onset between the two sexes suggested a modulation role for cholesterol and sex hormone like estrogen, which may influence the inflammatory response in the brain, so as to modulate the risk of AD. / In this project, the genetic risk factors predisposing to AD were investigated by genetic association studies of candidate genes. Candidate genes were shortlisted by two approaches. (I) Linkage-based candidate genes: Candidate genes were identified from reported loci with linkage to AD genome scan studies. Previous linkage studies of AD families revealed linked loci at 1p36, 1q23, 3p14, 4q32, 6p21, 6q27, 9q22, 10q24, 13q32, 15q26, 19q13 and 21q22. Several candidate genes from these loci including TNFalpha-related genes, TLR2, IGF-1, IFNalpha and MTHFR were selected for this project. (II) Hypothesis-based candidate genes: Candidate genes were selected according to their possible involvement in the inflammation hypothesis of AD. Under the hypothesis-based candidate gene approach, genes that might contribute to the inflammatory response of amyloid deposition were identified. These genes were validated by their expression level in the central nervous system. A further priorization step was carried out to select those genes showing a higher degree of inter-individual variation. Therefore, these genes were more likely to have a genetic/inherited variation at the population level. In other words, they are more likely to be the predisposition genes than genes without inter-individual variation (house-keeping genes are examples of genes showing little inter-individual variation). In this project, genes involved in the inflammatory pathway in the brain, such as IL-10 and HLA-A, and also genes that interact with the inflammatory pathway such as cholesterol related enzymes and estrogen receptors were investigated under the hypothesis-based approach. / This project is based on a case-control genetic association study which comprised of NINCDS-ADRDA diagnosed Chinese patients with AD (n=259) and age-matched non-demented subjects (n=248). Three genes PTGS2 (encoding for COX-2), MxA and ESR1 were selected for an intensive study by investigating their linkage disequilibrium pattern and using tagSNP strategy. TagSNPs selected for each gene were genotyped to investigate their association with the risk of AD. / This study showed that MTHFR, IL-10, HLA-A, CYP46A1, PTGS2 (COX-2) and ESR1 were associated with the risk of AD, and MxA, identified for the first time, was associated with the age of onset of AD. In conclusion, the results of my study further suggested the roles of inflammation in the pathogenesis of AD. / Ma Suk Ling. / "June 2006." / Advisers: Linda C. W. Lam; Nelson L. S. Tang. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1417. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 169-204). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
32

Simulation study on the validity of methods for detecting publication bias in meta-analysis for binary outcomes. / CUHK electronic theses & dissertations collection

January 2006 (has links)
Conclusions. The sensitivity and positive predictive value are generally more concerned than the specificity and negative predictive value in assessing and adjusting publication bias in meta-analyses. In this sense, Egger's regression can be recommended for its high sensitivity, while any positive result from Tang's method would suggest a probability of bias that should be taken seriously. Given the different patterns of the accuracy with the OR and the P1-P2 combination, a combination of Egger's regression and Tang's regression would be advisable. Further studies are needed to study the accuracy of methods used in combination. / Due to sampling error and true heterogeneity, a single study cannot provide a comprehensive picture and a precise estimate of, say the effectiveness of a treatment. Systematic reviews that identify and integrate relevant studies have become the most important scientific, quantitative method to summarize scientific research. Meta-analysis is the statistical method used in systematic reviews to combine results from individual studies. / However, due to selective submission and publication, not all relevant studies conducted, especially those unpublished studies with an insignificant negative result, are easily accessible to those who conduct reviews. As a result, the truth, say, the effect of a treatment, would be overestimated. This phenomenon is known as publication bias. A few methods for detecting the bias have been developed and used in meta-analyses. Although their accuracy has been studied, some important issues remain to be answered, such as when would a method be good enough for practical use and is it similarly good for different definitions of the odds ratio? / Methods. We conducted a simulation study to examine the accuracy of four commonly used bias-detection methods with various ORs and P1-P2 combinations. In a simulation study, the true bias status can be predetermined and thus be compared with the results of the bias-detection methods. The four methods are Egger's regression, funnel plot regression, rank correlation regression, and Tang's regression. Realistic sample size was used for simulating individual studies and the numbers of studies in a meta-analysis was also varied. Both the sensitivity and specificity are examined against the magnitude of the OR and the P1-P 2 combination to identify the ORs and P1-P 2 combinations for which a method is sufficiently accurate. Predictive values are also examined for the same reason and in the same manner. / Results. The sensitivity and positive predictive value are generally low and in particular when the OR is close to one for which publication bias is of a particular concern. Egger's regression has the highest sensitivity among the four, in particular when the OR is neither close to one nor exceptionally large or small. Due to the relatively lower specificity, the positive predictive value of Egger's regression is not as high as that for Tang's regression and funnel plot regression. Tang's regression and funnel plot regression are very similar in sensitivity, specificity and predictive values, with the former being slightly better. Rank correlation seems the least accurate method overall. Tang's regression has in general the highest positive predictive value among the four methods in particular when the OR is below one. / Chung Chi-keung. / "June 2006." / Adviser: Tang Jin Ling. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1588. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 116-124). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
33

Anthropometric, biochemical and hormonal interrelationships in essential hypertension. / CUHK electronic theses & dissertations collection

January 2006 (has links)
Based on previous studies, the increasing prevalence of hypertension may be associated with factors such as obesity, dietary salt and fat intake. This study examined the common biochemical and anthropometric markers that are associated with blood pressure elevation, increasing metabolic and haemodynamic derangement in subjects in Hong Kong, and related those phenotypic markers to some genetic polymorphisms relevant to hypertension. / Five hundred and thirty nine Hong Kong Chinese subjects were examined. They were aged from 20 to 60 years, and were hypertensive or normotensive siblings from families with a hypertensive proband, and normotensive controls without a family history of hypertension. The interrelationships between pathophysiological changes and various neurohormones considered relevant to the development of hypertension were investigated. Fasting blood and 24 hour urine samples were collected. Plasma insulin, plasma leptin, plasma renin activity (PRA), serum angiotensin converting enzyme (ACE) activity, aldosterone, 24 hour urine noradrenaline, adrenaline, dopamine and kallikrein were measured. A robust assay for the measurement of urine free cortisol and cortisone and 6beta-hydroxycortisol by an LC-MS/MS method was developed and validated. The ratio between urine free cortisol and cortisone was used as an estimate of the activity of 11beta-hydroxysteroid dehydrogenase type II (11betaHSD2) for cortisol metabolism. These parameters were related to polymorphisms in three genes, the angiotensinogen (AGT) gene M23 5T, the dopamine D1 receptor (DD1R) gene A-48G and the dopamine D2 receptor (DD2R) gene Taq1 A polymorphisms. Analysis of variance was employed for the parameters in the three groups of subjects and for an age-matched sibling pair analysis (using 1 normotensive and 1 hypertensive sibling from each family). Comparisons between parameters were also made after dividing the whole population into 3 groups according to the tertiles of blood pressure. (1) Central (higher waist to hip ratio and waist circumferences) and general (greater body mass index and weight) obesity were found in both hypertensive patients and the normotensive siblings compared to the control subjects. These obesity indices showed strong positive relationships with increased insulin resistance and blood pressure. The obesity indices were also independently associated with systolic and diastolic blood pressure, with central obesity showing the stronger associations. (2) Hypertensives had more adverse lipid profiles, insulin resistance and higher fasting plasma glucose levels. This suggested that the blood pressure elevation in the hypertensives may be mediated through obesity and insulin resistance. (3) Both the hypertensive and normotensive members of sibling pairs had lower noradrenaline and cortisol excretion and higher activity of 11betaHSD2 compared to the normotensive controls. The result showed positive relationships between noradrenaline and increased obesity, insulin resistance and blood pressure, while the relationship between adrenaline and blood pressure was inversed. (4) Lower plasma ACE activity and aldosterone were found in the hypertensives and their siblings than in the normotensive controls. There was a reduction in PRA across the blood pressure tertiles as blood pressure increased. In addition to the higher 11betaHSD2 activity, a negative relationship between aldosterone and blood pressure in hypertensive siblings was observed. These findings may indicate the protective mechanism of these systems in this population. In subjects with the different polymorphisms of AGT M235T, there were no differences in the PRA, serum ACE activity or aldosterone, but lower urine cortisol and kallikrien were found in relation to increasing numbers of the T allele. There was a weak association between the AGT M235T polymorphism and hypertension. (5) Despite the strong correlation of dopamine excretion between hypertensive and normotensive siblings within families, lower dopamine levels were found in the normotensive siblings. A consistent positive relationship was found between urine dopamine and sodium excretion, which supports the concept of the natriuretic effect of dopamine. There was no phenotypic difference found in any of the biochemical parameters in relation to the DDIR A-48G and DD2R Taq1 A polymorphisms, but there were weak associations with blood pressure and these polymorphisms in the sibling study. / The normotensive siblings had metabolic abnormalities similar to but less severe than the hypertensive probands, which suggests that the genetic effects and interacting effect of shared lifestyle and environmental factors with their hypertensive family member may be influential on the healthy siblings. Adaptive changes were seen in some of the blood pressure regulating systems in both the hypertensive probands and the normotensive siblings. The major factors predisposing to the hypertension in these subjects appeared to be obesity and insulin resistance and the adaptive changes were insufficient to compensate for these in the hypertensive subjects. / Chu Ten Wah Tanya. / "March 2006." / Adviser: Brian Tom Linson. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1547. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 304-341). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
34

An investigation into the integrity of circulating RNA in human plasma. / CUHK electronic theses & dissertations collection

January 2006 (has links)
Finally, the fourth part of this thesis demonstrated the potential of plasma RNA integrity for noninvasive clinical diagnosis. Based on previous reports of elevated RNase activities in the circulation of cancer patients, it was hypothesized that plasma RNA integrity might serve as a useful tumor marker. Using nasopharyngeal carcinoma (NPC) as a disease model, it was found that plasma RNA in untreated NPC patients was of lower integrity than that in healthy individuals. Further analysis showed that patients undergoing radiotherapy had increased RNA integrity in the post-treatment plasma samples. These findings hence suggested that measurement of plasma RNA integrity may provide a feasible approach for noninvasive cancer detection. / Much recent interest has been focused on the clinical applications of cell-free circulating RNA for molecular diagnostics. Despite the rapid development of plasma RNA as a potential diagnostic tool, much of the biology of these molecular species remains enigmatic. This thesis aimed to investigate the integrity of cell-free RNA molecules in plasma and to study the effects of different preanalytical factors on this new biological parameter. Moreover, the possibility that plasma RNA integrity might serve as a useful clinical marker was explored. / The first part of this thesis was to develop a quantitative method for analyzing RNA integrity in plasma. One-step real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used to amplify transcript sequences corresponding to multiple regions along a housekeeping gene, glyceraldehyde-3 phosphate dehydrogenase (GAPDH). It was demonstrated that 5' transcript fragments were predominant, when compared with those derived from the middle or 3' region, in the plasma of healthy individuals. This method was validated using two-step RT-PCR and serial dilution assays. / The potential generality of the underrepresentation of 3' mRNA fragments was further studied by using circulating placental RNA as a model system. Seven transcripts were analyzed in the plasma of pregnant women: the beta subunit of human chorionic gonadotropin (betahCG), tissue factor pathway inhibitor 2 (TFPI2), adrenomedullin (ADM), inhibin beta A subunit (INHBA), placenta-specific 1 (PLAC1), pregnancy-associated plasma protein A (PAPPA), and GAPDH. The second part of this thesis showed that for five of the seven genes, there appeared to be a greater abundance of transcript fragments arising from the 5' end than those from the 3' end in maternal plasma, and that for every gene under study, the 5'-specific assay had a higher rate of detection when compared to the 3'-specific one. Apart from biological significance, these data have implications for maximizing the sensitivity of fetal RNA detection in maternal plasma for future diagnostic use. / The results presented in this thesis not only have improved the current understanding of the biological nature of cell-free circulating RNA, but also have provided important information regarding the potential clinical utility of a new parameter, plasma RNA integrity, for the field of medical diagnostics. / To ensure accurate interpretation of the results on plasma RNA integrity, a number of preanalytical issues were investigated. In the third part of this thesis, several findings were described: (1) filtration of plasma samples did not change the observation that 5' end transcript was the predominant species; (2) time delay in the processing of plasma could lead to decreased RNA concentrations despite the lack of variation in plasma RNA integrity; and (3) repeated freezing and thawing of plasma samples, but not extracted RNA, could reduce RNA integrity significantly. / Wong Chi Kwan Blenda. / "August 2006." / Adviser: Yuk Ming Dennis Lo. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1453. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 148-184). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
35

Abnormal migration of vagal neural crest cells in dominant megacolon mouse embryos. / CUHK electronic theses & dissertations collection

January 2006 (has links)
Next, the influences on the migration of neural crest cell from the microenvironment of the hindgut through which the neural crest cells migrate were studied. An organ culture system was established to recombine different gut segments together at E11.5 for gut culture in order to trace the migration of neural crest cells from the midgut of the +/+ or Dom/+ embryo to the hindgut of the same or different genotypes. At E11.5, the midgut of both +/+ and Dom/+ embryos had already been fully colonized by neural crest cells, thus an explanted midgut segment (donor midgut) could serve as the source of the neural crest cells, while the caudal half of the hindgut (recipient hindgut) acted as the recipient of the neural crest cells from the donor midgut segment because at this stage, the caudal half of the hindgut was completely devoid of neural crest cells. After three days of culture, when a segment of midgut from the +/+ embryo was used as the donor of migratory vagal neural crest-derived cells and combined with an aneural segment of the hindgut (segment without neural crest-derived cells) from Dom/+ or Dom/Dom embryos, neural crest-derived cells from the midgut segment successfully crossed the combination junction and migrated normally along the hindgut segment to reach its caudal end within a normal developmental time frame. However, the migration of neural crest-derived donor cells from the Dom/+ midgut segment was abnormal in the recipient hindgut with a genotype of +/+, Dom/+ or Dom/Dom as evidenced by the retarded rostrocaudal progression of the vagal neural crest-derived cells and the reduced number of migratory cells in the recipient hindgut segment. These results thus indicate that the migration of the vagal neural crest-derived cells is minimally influenced by the migratory environment of the hindgut of the Dom embryo, and that the neural crest cells themselves may be defective in migration leading to the retarded migration in the hindgut of Dom mouse embryos. / The vagal neural crest cells originating from the region of the neural tube adjacent to somites 1 to 7 migrate along defined pathways to the gastrointestinal tract and then colonize the gut to give rise to the majority of neurons and glia of the enteric nervous system. Mutation of Sox10 in the Dominant megacolon (Dom) mouse, which is an animal model of Hirschsprung's disease, leads to aganglionosis (absence of ganglia) in varying lengths of the hindgut. To investigate the underlying cellular mechanism of aganglionosis, the migration of vagal neural crest cells from the neural tube to the gut (pre-enteric migration) in Dom mouse embryos at E8.5 was firstly traced with extrinsic cell markers, such as wheat germ agglutinin gold conjugates (WGA-Au) or fluorescent dye DiI. After the vagal neural crest cells entered the gut at E9.5, their migration was then followed by the examination of the expression of specific markers for undifferentiated neural crest cells with immunohistochemical staining. It was found that, although vagal neural crest cells in embryos of the three genotypes examined migrated along similar pre-enteric pathways at a similar migratory rate, the numbers of neural crest cells in embryos heterozygous (Dom/+) and homozygous (Dom/Dom) for the Sox10 mutation were significantly reduced when compared with the number of neural crest cells in wild-type (+/+) embryos. After vagal neural crest had entered the gut and from E10.5 onwards, no neural crest-derived cells were found in the gut of Dom/Dom embryos, and the migration of neural crest cells along the Dom/+ gut was significantly retarded from E12.5 onwards as compared with the migration in stage-matched +/+ embryos. / To further trace the cause of defective migration of neural crest cells in the Dom embryo, the proliferation and survival of neural crest cells were investigated with BrdU labeling and TUNEL assay. It was found that, although there was no obvious difference in the proliferating ability of vagal neural crest cells in embryos of all the three Dom genotypes studied during the pre-enteric migration and the migration in the gut, more apoptotic neural crest cells were found along the pre-enteric migratory pathway of Dom/Dom embryos than Dom/+ and +/+ embryos. Therefore, the decreased surviving ability, but possibly not the reduced proliferating ability, of neural crest cells during their pre-enteric migration may be partly responsible for aganglionosis in the hindgut of the Dom mouse. / Wang Liang. / "June 2006." / Adviser: W. Y. Chan. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1380. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 287-307). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
36

Functions of nogo in the development of mouse retinofugal pathway. / CUHK electronic theses & dissertations collection

January 2005 (has links)
Nogo is well established for its inhibitory action on axon regeneration in the adult central nervous system. It binds to the Nogo receptor (NgR) through an extracellular active site on the protein-Nogo-66. Although it is reported that Nogo is widely expressed in the developing brain, its exact function during development of the nervous system is unclear. / The contribution of Nogo on patterning the axon routing at the optic chiasm of mouse embryo was investigated in this thesis. Using immunocytochemical staining, Nogo protein was localized on the Miller glial cells in the retina and at the optic disk. A few migrating retinal neurons also expressed Nogo. In the chiasm, Nogo was localized exclusively on the radial glia, which generate a midline domain where turning of uncrossed axons occurs. In vitro study showed expression of NgR on retinal neurites and growth cones, and neurite outgrowth from both dorsal nasal (contralaterally projecting) and ventral temporal (ipsilaterally projecting) retina was inhibited by Nogo. In the pathway, NgR expression was regionally regulated. NgR was obvious in the optic stalk and the optic tract, but not in the chiasm. Blocking Nogo function with NEP1-40, a peptide antagonist of NgR, in brain slice culture of the pathway produced significant reduction in the uncrossed projection, but had no effect on axon crossing at the midline. Furthermore, the age related fiber arrangement in the optic tract was abolished after disturbing of Nogo function. Similar abnormalities were observed in slices treated with Nogo blocking antibody. In vitro studies showed that NEP1-40 rescued the inhibition of Nogo to the retinal neurites. The downregulation of NgR at the chiasm was supported by in vitro assays showing significant reduction of receptor expression on dorsal nasal but not ventral temporal growth cones when they encountered the chiasm, thus generating a differential inhibition to ventral temporal neurites. / These results provide evidences that Nogo is a guidance molecule during the development of CNS. Interaction of Nogo and its receptor plays important role for patterning the axon divergence in the mouse optic pathway and the age related fiber order in the optic tract. / Wang Jun. / "September 2006." / Adviser: Sun-On Chan. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1474. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 130-142). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
37

唐宋時期道士葉法善崇拜發展研究: 內道場道士、法師、地方神衹. / Study on the development of the daoist Ye Fashan cult in Tang and Song period: palace chapel daoist priest, ritual master and local deity / CUHK electronic theses & dissertations collection / Digital dissertation consortium / Tang Song shi qi dao shi Ye Fashan chong bai fa zhan yan jiu: nei dao chang dao shi, fa shi, di fang shen zhi.

January 2006 (has links)
Research materials will be drawn from four sources: various local historical resources, epigraphies, Daoist canon and popular literature like Tang strange writings. The project will make full use of epigraphies of local Daoist monasteries in the area of Chuzhou and local gazetteers of Zhejiang Province which inform historical development of the Ye Fashan cult in the region. / This study begins with the attempts to reconstruct the history of Palace Chapel Daoist Priest Ye Fashan and his Daoist family through analyzing the epigraphies of Ye's father, grandfather and himself. Before he died, Ye donated his houses as Daoist monasteries, which earned the clan's social reputation in the local society of Chuzhou, as well as for his offspring and local Daoist priests in the monasteries. Between the late Tang and the Song period, Ye was later worshiped as both the ancestor and local deity by the Ye clan. Local people even built ancestral temple in the Daoist monastery. Furthermore, Ye also received ample worships in many Daoist monasteries across the Chuzhou region because of his typical cultural hero activities such as making rains and controlling drought. / This thesis endeavors to explore the development of the local cult of Daoist priest Ye Fashan from the Tang Dynasty until the Song Dynasty. It aims at tracing the cult's historical and religious background within an academic context, which emphasizes studying history of Daoism and Daoist immortals in local society. / Ye Fa-shan is revered as a Daoist deity in many hagiographical sources found in the Daoist canon. The image of Ye in the Daoist hagiography is deeply influenced by strange writings and novels flourished in Tang, which emphasize the esoteric activities and thaumaturgy of Ye. His image as a Ritual Master in such narratives actually reflects the religious memory of the Tang people. Ye's esoteric image was further re-figured by new schools of Daoist ritual in the Song period. Ye was believed to be an important initiator of the Fu and Fa which were Daoist techniques to summon spirits and exorcise evils. In this thesis, the purpose of a biographical study of Ye Fashan is to acquire an archeological understanding of a Daoist cult between the Tang and the Song periods. Through an in-depth understanding of the popular literature and Daoist canon, the dissertation will try to reconstruct Ye's multiple images in local imagination and Daoist sources. / 吳真. / 論文(哲學博士)--香港中文大學, 2006. / 參考文獻(p. 203-218). / Adviser: Chi Tim Lai. / Source: Dissertation Abstracts International, Volume: 68-02, Section: A, page: 0608. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in Chinese and English. / School code: 1307. / Lun wen (zhe xue bo shi)--Xianggang Zhong wen da xue, 2006. / Can kao wen xian (p. 203-218). / Wu Zhen.
38

一個契約式均等主義理論. / Theory of contractual egalitarianism / CUHK electronic theses & dissertations collection / Yi ge qi yue shi jun deng zhu yi li lun.

January 2006 (has links)
In this thesis, we want to establish a theory of "contractual egalitarianism". It depends on the assumption that all people are free and equal. If all people are free and equal and they want to find a principle to govern their society, they would adopt a modified version of Scanlon's contractualism. According to this version of contractualism, a social practice or institution is unjust if it would be disallowed by any set of principles for the general regulation of society that no one could reasonably reject as a basis for informed, unforced general agreement. If we have good reasons not to adopt a certain kind of policies, then it is likely that any principles allowing such policies could be reasonably rejected, hence that they will be unjust. With this contractual framework, we argue that there are four kinds of reason---equal respect, fulfilling basic needs, fair political equality and fair equal opportunity---by which we can reasonably reject inequality. If we accept the contractual framework and adopt the four kinds of reason, then we can justify egalitarianism without appealing to the idea of substantive equality. This kind of egalitarianism is a moderate one. A more radical version of egalitarianism will be reasonably rejected for its conflict with our other important value, such as liberty and personal relationship. / 鄧偉生. / 論文(哲學博士)--香港中文大學, 2006. / 參考文獻(p. 181-186). / Adviser: Yuen Kang Shih. / Source: Dissertation Abstracts International, Volume: 68-02, Section: A, page: 0602. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in Chinese and English. / School code: 1307. / Lun wen (zhe xue bo shi)--Xianggang Zhong wen da xue, 2006. / Can kao wen xian (p. 181-186). / Deng Weisheng.
39

Phytochemical characterization and supercritical fluid extraction of bioactive triterpenes from ganoderma lucidum. / CUHK electronic theses & dissertations collection

January 2006 (has links)
Aims. The objectives of this study were (i) to isolate and characterize by conventional column chromatography, structurally diverse triterpenes from G. lucidum to serve as chemical markers; (ii) to develop a high performance liquid chromatography (HPLC) method for the quality control and/or standardization of Lingzhi-containing products; (iii) to utilize and optimize operating conditions for the newer extraction technology: supercritical fluid extraction (SFE), in order to maximize yields of bioactive triterpenes, and to reduce time and costs. / Background. The dried fruiting body of Ganoderma lucidum, commonly known as Lingzhi, has been used extensively as a traditional Chinese medicine (TCM) for many centuries not only in China, but also in other countries such as Japan and Korea. In recent years, Lingzhi has also become a popular health supplement in many Western countries. The chemical composition of Lingzhi is complex, but it has been well documented that the lipophilic triterpenoid class of compounds possess a range of biological effects that include antitumor, immunomodulatory, cardiovascular, respiratory and antihepatotoxic activity. A major drawback in TCM research has been the lack of authentic chemical standards, and efficient methods for the extraction and analysis of bioactive fractions and/or single components. Conventional extraction methods for G. lucidum are time-consuming and laborious, and often result in low yields of useful chemical constituents. / Conclusion. This study enabled the development of a method for the simultaneous analysis of structurally diverse triterpenes with remarkably different chromatographic profiles. The isolated triterpenes, as chemical markers, and the HPLC method can readily be used for quality control and/or standardization purposes in evaluating Lingzhi-containing products. Optimization of operating conditions for SFE facilitated the rapid and selective extraction of acidic triterpenes from raw G. lucidum in significantly higher yields. / Methods. Raw material of G. lucidum was extracted with 80% ethanol; subjected to repeated column chromatography to purify triterpenes; and characterized by NMR (1H and 13C) and mass spectroscopy. Isolated lipophilic triterpenes were qualitatively and quantitatively analyzed by reversed-phase HPLC using an ODS column (150 x 4.6 mm) and PDA detection at 256 nm. The assay was validated over appropriate concentration ranges and benzophenone was used as an internal standard. Supercritical fluid extraction of G. lucidum was carried out using a commercial supercritical fluid extractor system Thar, SFE-1000M. Briefly, the raw powder of G. lucidum was soaked in ethanol containing 10% aqueous ammonia for 30 minutes prior to extraction. Extractions were performed at temperatures of 40, 50 and 60°C; and pressures of 200, 250, 300 and 350 bar; 5% ethanol was used as the co-solvent; and the flow rate of CO 2 was set at 20 g/min. / Results. Eight compounds were isolated and identified from G. lucidum: four triterpenes; namely, lucidenic acid N, ganoderic acid B, ganodermanontriol, and ganodermadiol; two steroids; ergosterol-7, 22-dien-3beta-ol and ergosterol peroxide; and two fatty acids, oleic acid and tetracosanoic acid. The four triterpenes were utilized as chemical markers, and the developed HPLC method was able to simultaneously analyze the structurally diverse components with good resolution. The total analysis run time was 110 min, and retention times (tR) were 14.88, 18.96, 63.88 and 90.73 min respectively, and the eluting system was a mixture of three solvents, methanol (A), acetonitrile (B) and 2% acetic acid solution (C): 0-22 min, 5% A, 25% B and 70% C; 22-85 min, gradient elution, the ratio changed gradually to 5% A, 80% B and 15% C; 85-110 min, gradient elution, the ratio changed gradually to 5% A, 85% B and 10% C. The validated HPLC method and the isolated chemical markers were effectively applied to determine the triterpenoid contents in a variety of commercial Lingzhi products. Supercritical fluid extraction conditions of: pressure 300 bar and temperature 50°C, gave the highest yields of triterpene-containing extracts. HPLC analysis of the SFE extracts showed predominantly acidic triterpenes such as lucidenic acid N and ganoderic acid B. / Hong Xin. / "December 2006." / Advisers: Ho Yee Ping; Albert H. L. Chow. / Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5968. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 149-175). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
40

A novel growth hormone receptor subtype in black seabream: cDNA cloning, regulation of gene expression and its disruption by environmental estrogens. / CUHK electronic theses & dissertations collection

January 2006 (has links)
In the tissue distribution study, the expression of GHR2 is significantly higher than GHR1 in many tissues of the seabream including the gonad, kidney, muscle, pituitary and spleen. In vivo hormone treatment data indicated that cortisol and testosterone have differential expression regulation between GHR1 and GHR2. On the other hand, hepatic expression of both GHR1 and GHR2 in seabream was decreased by estradiol treatment. In primary cultures of seabream hepatocytes, the expression patterns after treatment by the various concentrations of hormones were consistent with the in vivo results. / To study the actions of environmental estrogens on the somatotropic axis, a transgenic yeast system was developed for estrogenicity screening. The fish estrogen receptor (gfER) and a reporter vector containing the estrogen responsive element (ERE) were expressed in yeast cells as a means to identify potential estrogens. Using this system, more than fifty chemicals including pesticides, herbicides, industrial chemicals and phytoestrogens were screened. Ten compounds including dibutyl phthalate (DBP) and bisphenol A (BPA) were demonstrated to exhibit estrogenic activities. And a compound (malachite green, MG) with novel anti-estrogenenic activities was identified. Then BPA and MG were focused to explore the disrupting effects of environmental estrogens on the two GHRs. Through the method of real-time PCR, both compounds could attenuate the gene expression level of GHRs in seabream hepatocytes. Using the method of luciferase assay, the signal transduction of the two GHRs was found to be desensitized by both BPA and MG. / Two genomic contigs of putative growth hormone receptor (GHR) were identified in fugu and zebrafish genomes by in silico analysis, suggesting the presence of two GHR subtypes in a single teleost species. This hypothesis was tested by cloning the full-length cDNA sequence of a second GHR subtype from the black seabream in which the first GHR subtype has been previously reported. Phylogenetic analysis of known GHR sequences from various vertebrates revealed that fish GHRs cluster into two distinct clades, viz. GHR1 and GHR2. The biological activities of both GHR subtypes from seabream had been examined using the reporter transcription assays in cultured eukaryotic cells. It was demonstrated that both of them have differential signal transduction upon Spi 2.1, beta-casein and c-fos promoter activities. / by Jiao, Baowei. / "December 2006." / Adviser: Christopher H. K. Cheng. / Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5662. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 150-180). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Page generated in 0.641 seconds