Thesis (M.P.H.)--University of Hong Kong, 2008. / Includes bibliographical references (p. 108-124).

Thèse (Ph.D.)--Université Laval, 2003. / Titre de l'écran-titre (visionné le 22 mars 2004). Bibliogr.

Purpose Primary Open Angle Glaucoma (POAG) is an important cause of irreversible visual loss in South Africa. POAG is asymptomatic, yet early detection and treatment can prevent visual loss. POAG has a genetic component, and identifying genetic risk factors could facilitate early detection as well as elucidate pathogenic mechanisms of the disease. POAG is more common in populations of African descent, but has been understudied in the context of POAG genetic risk factors in these populations. The purpose of this research was to identify genetic risk factors for POAG in black South Africans. Methods Self-identified black South African POAG patients and unaffected control participants were enrolled at St John Eye Hospital in Soweto. The study population was evaluated in case-control association studies for genetic risk factors in the following genomic regions: CDKN2B/CDKN2BAS-1, MYOC, TMCO1, CAV1/CAV2, CYP1B1, WDR36, COL1A1, COL1A2, COL5A1, COL8A2, ZNF469, SIX1/SIX6, ATOH7 and the chromosome 2p16 locus. The study was powered to detect moderate-sized genetic effects. Family members of participants identified with potentially pathogenic mutations in MYOC were counselled, screened for the mutations and clinically screened for glaucoma. Genotyping data from SNPs in TMCO1, CAV1/CAV2, CDKN2BAS-1 and SIX1/SIX6 that had also been genotyped in a West African and an African American population were compared with the South African data and the three datasets were combined to create a larger sample of individuals of African descent for association analyses. Results There were 247 POAG patients and 255 control participants enrolled in the study that were representative of the black population of South Africa. The POAG participants had advanced disease with more than half having severe visual impairment from the disease. Potentially pathogenic mutations in MYOC were identified in 4.2% of the POAG patients (Lys500Arg in 1.2%, Gly374Val in 0.9% and Tyr453del in 2.3%) and in 20% of the family members screened. The screening successfully identified individuals at high risk for future visual loss and enabled them to receive counselling and follow-up. Lys500Arg is a benign variant, whereas Gly374Val and Tyr453del are pathogenic. Tyr453del is incompletely penetrant. In the association studies, single SNPs in the COL1A1, ZNF469 and MYOC regions showed marginal associations with POAG, but the identified associations did not withstand correction for multiple testing. Ocular quantitative trait association analyses also yielded no significant associations after correction but a significant association was identified with type 2 diabetes mellitus and rs12522383 in WDR36. There was also a significant association identified with SNP rs10120688 in CDKN2BAS-1 and visual impairment in the African American dataset. Combining the three datasets of individuals of African descent increased the power to detect small genetic effects and identified suggestive associations with SNPs in TMCO1 and CAV1/CAV2. Conclusions Black South Africans with POAG may have a MYOC mutation that either causes or contributes to their risk for developing POAG in approximately 3.3%. MYOC mutation screening in affected families successfully demonstrated the value of genetic information in identifying and protecting individuals at risk for visual loss from glaucoma. The genetic risk associated with the candidate genes evaluated in this study and POAG in black South Africans, if such a risk exists, is a small risk. There is therefore a critical need for further genetic association studies in POAG in this significantly affected population to identify other genetic risk factors. This study has important implications for the management and counselling of black South African patients with POAG and their families.

No description available.

Embora muito estudados, os efeitos da extração dos quatro primeiros pré-molares sobre as alturas faciais ainda causam certa controvérsia. Devido à variação de resultados encontrados na literatura e pelo fato de todos os estudos terem sido realizados em leucodermas, propusemonos a analisar cefalometricamente as alterações das alturas faciais anterior e posterior em pacientes nipo-brasileiros com más oclusões de Classe I e II, 1a divisão de Angle tratados ortodonticamente. A amostra consistiu de quatro grupos: Grupo I – 15 jovens com Classe I tratados com extração dos quatro primeiros pré-molares; Grupo II – 15 jovens com Classe I tratados sem extrações; Grupo III – 14 jovens com Classe II, 1a divisão tratados com extração dos quatro primeiros pré-molares; Grupo IV– 15 jovens com Classe II, 1a divisão tratados sem extrações. Todos foram tratados com a técnica do Arco de Canto Simplificada por um período médio de 2,49 anos. A idade média inicial foi de 12,14 anos e a final de 14,64 anos. A análise dos resultados revelou que a extração de pré-molares não diminui a dimensão vertical em pacientes nipo-brasileiros com padrão de crescimento equilibrado, uma vez que as alterações nas alturas faciais anterior e posterior foram similares nos quatro grupos estudados, apresentando aumento de ambas ao final do tratamento ortodôntico. As alterações dos ângulos FMA e SN.GoGn não foram estatisticamente significantes e, quanto ao Índice de Horn e à proporção AFP/AFA, verificou-se aumento nos Grupos I e III. Observou-se dimorfismo apenas nas medidas dentoalveolares DMSPTV e DMI-PTV, no Grupo I, e nas medidas CMI-PM, PFH e AFP, no Grupo III, em que o gênero masculino apresentou valores maiores que o feminino. / The objective of this retrospective longitudinal cephalometric investigation was to study the influence of extraction and nonextraction orthodontic treatment on the facial height japanese children and grandchildren with Class I and Class II, Division 1 malocclusions. The sample included 59 mesocephalic subjects distributed in to 4 groups: group I- Class I treated with first bicuspid extractions (9 males and 6 females); group II- Class I treated without extraction (8 males and 7 females); group III- Class II, Division 1 treated with first bicuspid extractions (7 males and 7 females); group IVClass II, Division 1 treated without extraction (7 males and 8 females). The initial mean age was 12.14 years and all groups were treated with the Edgewise simplified technique, during a mean period of 2.49 years. The resulted changes were compared by the ANOVA. There were no statistically significant differences (p 0,05) in the first bicuspid extractions orthodontic treatment when compared to the nonextraction treatment in both Class I and Class II, Division 1. The t test showed that extraction treatment in Class I and II (groups I and III) is associated with a significant increase in the Horn index and PFH/AFH ratio. In addition, FMA and SN.GoGn did not change statistically. No sexual dimorphism was encountered for the anterior and posterior facial height changes, except for some dentoalveolar measurements (U6-PTV and L6-PTV) in Group I, where males achieved higher values than females. In group III, greater changes in L6-MP, PFH and S-Go were also demonstrated by male patients.

Embora muito estudados, os efeitos da extração dos quatro primeiros pré-molares sobre as alturas faciais ainda causam certa controvérsia. Devido à variação de resultados encontrados na literatura e pelo fato de todos os estudos terem sido realizados em leucodermas, propusemonos a analisar cefalometricamente as alterações das alturas faciais anterior e posterior em pacientes nipo-brasileiros com más oclusões de Classe I e II, 1a divisão de Angle tratados ortodonticamente. A amostra consistiu de quatro grupos: Grupo I – 15 jovens com Classe I tratados com extração dos quatro primeiros pré-molares; Grupo II – 15 jovens com Classe I tratados sem extrações; Grupo III – 14 jovens com Classe II, 1a divisão tratados com extração dos quatro primeiros pré-molares; Grupo IV– 15 jovens com Classe II, 1a divisão tratados sem extrações. Todos foram tratados com a técnica do Arco de Canto Simplificada por um período médio de 2,49 anos. A idade média inicial foi de 12,14 anos e a final de 14,64 anos. A análise dos resultados revelou que a extração de pré-molares não diminui a dimensão vertical em pacientes nipo-brasileiros com padrão de crescimento equilibrado, uma vez que as alterações nas alturas faciais anterior e posterior foram similares nos quatro grupos estudados, apresentando aumento de ambas ao final do tratamento ortodôntico. As alterações dos ângulos FMA e SN.GoGn não foram estatisticamente significantes e, quanto ao Índice de Horn e à proporção AFP/AFA, verificou-se aumento nos Grupos I e III. Observou-se dimorfismo apenas nas medidas dentoalveolares DMSPTV e DMI-PTV, no Grupo I, e nas medidas CMI-PM, PFH e AFP, no Grupo III, em que o gênero masculino apresentou valores maiores que o feminino. / The objective of this retrospective longitudinal cephalometric investigation was to study the influence of extraction and nonextraction orthodontic treatment on the facial height japanese children and grandchildren with Class I and Class II, Division 1 malocclusions. The sample included 59 mesocephalic subjects distributed in to 4 groups: group I- Class I treated with first bicuspid extractions (9 males and 6 females); group II- Class I treated without extraction (8 males and 7 females); group III- Class II, Division 1 treated with first bicuspid extractions (7 males and 7 females); group IVClass II, Division 1 treated without extraction (7 males and 8 females). The initial mean age was 12.14 years and all groups were treated with the Edgewise simplified technique, during a mean period of 2.49 years. The resulted changes were compared by the ANOVA. There were no statistically significant differences (p 0,05) in the first bicuspid extractions orthodontic treatment when compared to the nonextraction treatment in both Class I and Class II, Division 1. The t test showed that extraction treatment in Class I and II (groups I and III) is associated with a significant increase in the Horn index and PFH/AFH ratio. In addition, FMA and SN.GoGn did not change statistically. No sexual dimorphism was encountered for the anterior and posterior facial height changes, except for some dentoalveolar measurements (U6-PTV and L6-PTV) in Group I, where males achieved higher values than females. In group III, greater changes in L6-MP, PFH and S-Go were also demonstrated by male patients.

Dexamethasone (DEX) and triamcinolone acetonide (TA) are widely used in clinical practice for ocular anti-inflammation. The most common side effect of these two corticosteroids is the rise of intraocular pressure that leads to death of the retinal ganglion cells, a feature of POAG. We investigated the differential gene expression profiles induced by DEX and TA treatment in human trabecular meshwork (hTM) cells using microarray technology. A number of genes differentially expressed in hTM cells were identified under DEX and TA treatment, mainly involving in proteolysis, cell adhesion and acute phase response. Five genes (MYOC, GAS1, SENP1, ZNF343 and SOX30) were commonly differentially expressed in both DEX and TA treatment. It indicates that DEX and TA may share similar effect on hTM cells, which may associate with the onset of ocular hypertension. / In one Chinese juvenile onset POAG (JOAG) family with autosomal dominant inheritance, a novel locus at 15822-q24 (GLC1N) was identified using genome-wide scan, supported by clinical, linkage, and haplotype transmission data. The critical region covered a genetic distance of 16.6 Mb. To search for disease genes within this new JOAG locus, we screened NR2E3, SMAD6 and CLN6 for mutations. However, no mutations was found in the family members. We attempted a new gene-based SNPs genotyping approach to search for susceptibility genes to JOAG in this novel locus by using 97 unrelated JOAG patients and 99 unrelated control subjects. Significant association was identified in a set of 6 adjacent SNPs out of 122 gene-based SNPs. Among them, one non-synonymous SNP rs3743171 in the SLC24A1 gene was incompletely segregated in the JOAG family. Our findings indicate the mutation in other regions of SLC24A1 may be responsible for JOAG in this family, or another gene in this region may be the actual cause of glaucoma. / Primary open angle glaucoma (POAG) is a leading cause of visual impairment and blindness worldwide. Genetic factors play a major role in the etiology of POAG. This thesis describes our investigations of the POAG causative genes using genome-wide DNA scanning by linkage/association analysis and RNA level scanning by microarray technology. / Wang Danyi. / "September 2006." / Adviser: Calvin Chi Pui Pang. / Source: Dissertation Abstracts International, Volume: 68-08, Section: B, page: 5155. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 139-181). / 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.

This study evaluated the soil properties of clean sand, a silty sand, and a road base that are extensively used as a backfill for full-scale testing at Riverside Campus at Texas A&M University. The three soils were collected at the Riverside Campus and the testing schedule included grain size analysis, hydrometer test, specific gravity, maximum dry density, Atterberg limit, stiffness, direct shear test, triaxial test, and a simple procedure to estimate the maximum and minimum void ratio of the clean sand. Relation between strength/deformation, vertical displacement/shear displacement, and physical properties were evaluated to estimate the frictional resistance and angle of dilation of the clean sand and the silty sand. Numerical simulations of the Direct Shear Test (DST) were conducted on the clean sand using Finite Element Model in the computer program LS-DYNA. The simulations were intended to reproduce the Direct Shear Test (DST) to estimate the frictional resistance and dilatancy effects of the clean sand under different compressive stresses. Field tests were also conducted on the clean sand and the road base. These tests included the in-situ density determination, in-situ water content, and the soil modulus using the Briaud Compaction Device (BCD).

This paper is divided into two parts, experiments and finite element simulations. In experiments, the effects of various rolling conditions such as roll rotational speed, reduction, upon entrance and exit axial velocities, entrance and exit rotational speeds, twisting angle of rolled products are investigated. Experiments with roll rotation and planetary rotation are carried out to check the validity of the results obtained by roll rotation only. In finite element simulations, DEFORM 3D is used to simulate planetary three-roll rolling. The rolling torque, the distance between spirals, and the shape are analyzed, and the analytical results are compared with experimental results.

Le phénomène de mouillage intervient dans de nombreux procédés, parmi lesquels la galvanisation en continu de tôles d’acier pour carrosserie automobile. Dans ce procédé, la tôle est immergée dans un bain de zinc liquide afin de la recouvrir d’une couche protectrice de zinc. Mais avant cela, cette tôle, laminée à froid, est soumise à un recuit sous atmosphère réductrice dans le but d’éliminer l’écrouissage et les oxydes de fer superficiels et favoriser ainsi les réactions de galvanisation. Des nouveaux aciers, dits à haute limite d’élasticité, ont été élaborés afin d’améliorer la sécurité passive des véhicules sans trop augmenter leur masse et leur consommation de carburant. Ces aciers contiennent des teneurs élevées en éléments d’addition oxydables qui, lors du recuit, diffusent de la masse de l’acier vers la surface où ils forment des particules d’oxydes qui ne sont pas mouillées par le zinc liquide. Il parait donc important de comprendre le mouillage par le zinc liquide de surfaces hétérogènes, composées de fer métallique et d’oxydes. Pour cela, nous avons étudié l’étalement d’une goutte de zinc liquide, à des temps très courts, à l’aide d’une caméra rapide dans un dispositif de chute de goutte. Nous avons mené nos expériences sur des alliages fer – silicium et un acier industriel, recuits à haute température avant le dépôt de la goute, ce qui a permis d’obtenir un taux de couverture par les oxydes variant de 0 à 100%. Le mouillage est décrit à l’aide de deux paramètres : le diamètre d’étalement et l’angle de contact. Nous nous sommes attachés à la compréhension et à la modélisation de l’évolution de ces deux paramètres aux cours des premiers instants de contact et en fin d’étalement. Nous avons, en particulier, mis en évidence l’influence du taux de couverture par les oxydes et de l’énergie cinétique initiale de la goutte. Le manuscrit se termine par une extrapolation des résultats de mouillage obtenus pour les surfaces hétérogènes modèles à des substrats recuits dans des conditions voisines du recuit continu industriel / Wetting phenomenon takes place in several processes among which continuous galvanizing of steel sheet for car bodies. In this process, the steel sheet is immersed in a zinc bath in order to cover it with a protective zinc layer. But before that, the cold rolled steel sheet is annealed in a reducing atmosphere in order to eliminate the cold working and the superficial iron oxides improving thereby the galvanizing reactions. New steels, called advanced high strength steels, have been developed in order to improve vehicle safety without increasing their weight and therefore fuel consumption. These steels contain high amounts of oxidizable alloying elements that segregate during the annealing to the surface where they form oxides particles that are not wetted by liquid zinc. Therefore it seems important to understand the wetting by liquid zinc of heterogeneous surfaces composed by metallic iron and oxides. For this purpose, we studied the spreading of liquid zinc droplet at very short time using a high speed camera by means of a dispensed drop apparatus. In our experiments we have used different iron – silicon alloys and a commercial steel, annealed at high temperature before the wetting experiments, leading to surface coverage by oxides lying from 0 to 100%. Wetting is described using two parameters: the spreading diameter and the contact angle. We have focused on the comprehension and modelling of the evolution of these two parameters during the first time of contact and at the end of spreading. The influence of both the surface coverage by oxides and the initial kinetic energy of the droplet has been investigated. The results obtained for the wetting of the model heterogeneous surfaces are extrapolated to substrates annealed in the same conditions as in industrial continuous annealing.