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  • 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.
1

Bayesian quadrature and Bayesian rescaling

Kennedy, Marc January 1996 (has links)
No description available.
2

The outcome of posterior urethral valves: a twenty one year experience

Petersen, Karen Lavinia 11 November 2009 (has links)
M.Med. (Paediatrics), Faculty of Health Sciences, University of the Witwatersrand, 2008 / Background: Posterior urethral valves (PUV) result in a spectrum of obstruction, and up to thirty percent of patients progress to renal failure. Objective: Descriptive study of patients with PUV, and to compare growth and renal function in the primary valve ablation versus vesicostomy group. Methods: Retrospective record review of patients with PUV at Chris Hani Baragwanath Hospital from January 1985 to December 2005. Results: A total of 128 boys were identified. The mean (range) age was 12.9 months (0 to 139.4). The mean duration of follow-up was 42 months, with 65% lost to follow- up. UTI and voiding problems were the most common modes of presentation. Young age at presentation and renal dysfunction after surgery were poor prognostic features. Hydronephrosis was present in 89.5%. Renal failure was present in 37% of patients at last visit. Primary valve ablation was performed in 44.2% and vesicostomy in 55.8%. No statistical difference in renal outcome or somatic growth was observed between the surgical groups. Conclusion: PUV is a common condition with significant morbidity. The renal outcome in black South African boys is similar to reports from developed countries. The type of initial surgical management did not impact on renal outcome or somatic growth.
3

Prediction and Variable Selection

Dey, Tanujit 24 June 2008 (has links)
No description available.
4

Safety and Visual Outcomes of Novel Abexterno Akreos® Single Pass Method of Transscleral Sutured Posterior Chamber IOL Implantation for Scleral Fixation of IOL

Wallman, Andrew 20 April 2016 (has links)
A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / We present the safety and efficacy of a novel transscleral sutured posterior chamber intraocular lens (TSSPCIOL) implantation approach utilizing 25 gauge vitrectomy and a foldable posterior chamber intraocular lens implant (AKREOS AO60, Bausch & Lomb). 80 consecutive eyes that underwent single surgeon TSSPCIOL implantation between October 2008 and July 2012 at a referral‐based retina institution were analyzed for best spectacle‐corrected visual acuity (BCVA) and safety indicators. Postoperative complications included retinal detachment in 2 eyes (2.5%), Irvine‐Gass cystoid macular edema in 3 eyes (3.75%), with 2 of those cases occurring late, persistent postoperative corneal edema in 1 eye (1.25%), hyphema in 2 eyes (2.5%) and 1 case of postoperative vitreous hemorrhage with spontaneous clearing. The modified external approach with AKREOS® TSSPCIOL placement with 25 gauge vitrectomy has relatively few complications, improves visual acuity in patients requiring TSSPCIOL, and offers several advantages over traditional anterior chamber or conventional scleral sutured techniques.
5

Control of knee stability by internal devices

Olanlokun, Kola Folorunsho January 2000 (has links)
No description available.
6

Knowing what you don't know : roles for confidence measures in automatic speech recognition

Williams, David Arthur Gethin January 1999 (has links)
No description available.
7

Avaliação biomecânica da técnica onlay para reconstrução do ligamento cruzado posterior: comparação entre as fixações unicortical e bicortical do enxerto na tíbia / Onlay reconstruction of the posterior cruciate ligament: biomechanical comparison of unicortical and bicortical tibial fixation

II, João Bourbon de Albuquerque 21 May 2018 (has links)
As lesões do ligamento cruzado posterior (LCP) geralmente estão associadas a traumas de alta energia. Ainda existem muitas controvérsias sobre a técnica cirúrgica ideal para o tratamento dessas lesões, no que diz respeito aos métodos de seleção e fixação do enxerto. A técnica onlay, recentemente descrita, permite a fixação direta de um autoenxerto de tendões flexores ao aspecto posterior da tíbia com parafuso esponjoso e arruela dentada plástica, com proteção às estruturas neurovasculares e evitando a chamada \"curva assassina\". O objetivo deste estudo foi realizar uma avaliação biomecânica da técnica onlay, comparando entre si as fixações tibiais unicortical e bicortical de enxertos, imediatamente após o implante (tempo zero). O ensaio biomecânico e a coleta de dados foram realizados no Thompson Laboratory for Regenerative Orthopaedic da Universidade de Missouri (Columbia, Missouri, EUA). Para isso, oito joelhos de espécimes cadavéricos foram distribuídos aleatoriamente em uma das duas técnicas de fixação do LCP (n = 4 joelhos/técnica), que foram realizadas por cirurgiões experientes no procedimento. O teste biomecânico consistiu em uma força com direção posterior aplicada a região proximal da tíbia, em quatro ângulos de flexão do joelho, 10o, 30o, 60o e 90o. O teste foi realizado com uma taxa de deslocamento de 1 mm/s, em uma máquina servo-hidráulica (8821s, Instron, Norwood, MA). As variáveis medidas foram: carga para 5 mm de deslocamento posterior, deslocamento máximo (com carga de 100 N) e rigidez. Para a análise estatística, os dados de cada joelho foram normalizados para o joelho com LCP nativo intacto e depois agrupados nas categorias unicortical ou bicortical, de acordo com a fixação realizada. Dados obtidos, nas variáveis mencionadas, para os grupos joelho intacto, joelho desbridado, unicortical e bicortical, foram comparados por meio da análise de variância simples (one-way ANOVA) para avaliar diferenças estatisticamente significativas (p < 0,05). Quando comparadas aos joelhos com LCP desbridado, as técnicas de fixação unicortical e bicortical apresentaram menor frouxidão a uma carga máxima de 100N. Quando comparados com os joelhos intactos, o grupo unicortical apresentou maior frouxidão em todos os ângulos e o grupo bicortical apresentou maior frouxidão apenas a 90o de flexão (p < 0,001). Na avaliação da força relativa do enxerto, ou seja, a carga necessária para atingir 5 mm de deslocamento na gaveta posterior, as técnicas unicortical e bicortical exigiram menos carga que os joelhos com LCP intacto. O grupo com fixação bicortical, no entanto, foi superior ao unicortical em todos os ângulos (p < 0,001), na avaliação da força relativa. Em relação à rigidez, não houve diferenças significativas entre os grupos unicortical e bicortical e ambos foram superiores aos joelhos desbridados e inferiores aos joelhos com LCP intacto. Com base nos testes biomecânicos de cadáveres, nenhuma das técnicas de reconstrução do LCP foi capaz de reproduzir os resultados do joelho com LCP intacto, mas ambas as técnicas foram superiores aos joelhos com deficiência de LCP. Ao se optar pela técnica onlay de reconstrução do LCP, a técnica de fixação tibial bicortical parece ter vantagens biomecânicas em relação à técnica de fixação unicortical. / Posterior cruciate ligament (PCL) injuries are generally associated with high energy trauma. There are many controversies regarding optimal surgical technique in regard to graft selection and fixation methods. The recently described onlay technique allows for direct fixation of a hamstring autograft to the posterior aspect of the tibia, protecting the neurovascular structures and avoiding the so-called \"killer turn\". The onlay technique requires a cancellous screw and spiked washer to secure the graft to the tibia. The objective of this study was to compare immediate post-implantation biomechanics of unicortical versus bicortical tibial fixation of onlay PCL grafts. Biomechanical testing and data collection were performed at the Thompson Laboratory for Regenerative Orthopedics at the University of Missouri (Columbia-Missouri-USA). For that, eight knees were randomly assigned to one of two onlay PCL techniques (n= 4 knees/technique), performed by surgeons experienced with the procedure. Testing consisted of a posterior-directed force at four knee flexion angles, 10, 30, 60, and 90 degrees, at a displacement rate of 1 mm/s, performed in a servo-hydraulic machine (8821s, Instron, Norwood, MA). Measured variables were: load to 5 mm of posterior displacement, maximum displacement (at 100 N load) and stiffness. For statistical analyses, data for each knee were normalized to the native PCL-intact knee and then grouped into unicortical or bicortical groups accordingly. Data for load to 5 mm (strength), displacement at 100 N, and stiffness were compared among PCL-intact, PCL-deficient, unicortical fixation, and bicortical fixation categories using one-way analysis of variance (ANOVA) to assess for statistically significant (p < 0.05) differences. When compared to PCL-deficient knees, both unicortical and bicortical fixation techniques had less laxity at a maximum load of 100N. When compared with PCL-intact knees, unicortical had more laxity at all angles and bicortical had more laxity only at 90 degrees (p < 0.001). For relative graft strength, namely the load required to reach 5mm of displacement in posterior drawer, unicortical and bicortical techniques required less load to 5 mm of posterior drawer than for PCL-intact knees. Bicortical, however, outperformed unicortical at all angles (p < 0.001) for relative strength. Regarding stiffness of each construct, there were no significant differences between unicortical and bicortical and both were superior to PCL-deficient and inferior to PCL-intact knees. Based on cadaveric biomechanical testing, none of the reconstructed PCL knees was able to replicate the intact native PCL, but both techniques were superior to PCLdeficient knees. The bicortical tibial fixation technique appears to have biomechanical advantages when opting for onlay PCL reconstruction.
8

Estudo do gene LHX4 em pacientes com hipopituitarismo associado a neuro-hipófise ectópica / Molecular analysis of the LHX4 gene in hypopituitary patients with ectopic posterior pituitary lobe

Melo, Maria Edna de 12 December 2005 (has links)
INTRODUÇÃO: O hipopituitarismo está associado, em cerca de 40% dos casos, à ectopia da neuro-hipófise observada em imagem por ressonância magnética (RM). Nestes pacientes a visualização da haste ocorre predominantemente nos que têm deficiência isolada de GH (DIGH), enquanto a não visualização da mesma está mais associada à deficiência hipofisária múltipla (DHM). A etiologia deste quadro, no entanto, permanece indeterminada na maioria dos pacientes. A elevada freqüência de parto pélvico e de complicações neonatais sugere uma causa traumática, enquanto que relatos de casos familiares, associação com outras patologias do SNC e descrição de mutações nos genes HESX1, LHX4 e SOX3 apontam para uma causa genética. O LHX4 é um fator de transcrição envolvido na embriogênese hipofisária fundamental para a formação da bolsa de Rathke definitiva. O LHX4 está localizado no cromossomo 1q 25, possui 6 éxons e estende-se por mais de 45 kb de DNA genômico. A única mutação publicada neste gene em humanos é a IVS4-1G>C, associada a um fenótipo caracterizado por baixa estatura, deficiências de GH, TSH e ACTH, neuro-hipófise ectópica e malformação Arnold-Chiari tipo I. O objetivo do estudo é analisar as regiões exônicas e éxon-íntron do LHX4 e caracterizar o perfil hormonal, correlacionando com os achados de RM, em 63 pacientes com hipopituitarismo associado a neurohipófise ectópica. MÉTODOS: Os pacientes foram submetidos à avaliação hormonal e por imagem através de ressonância magnética. A análise molecular incluiu amplificação do gene por PCR, seqüenciamento automático e uso de enzima de restrição. RESULTADOS: A visualização da haste ocorreu em 21 pacientes; destes, 10 (48%) apresentaram DIGH. A não visualização da haste foi mais associada a DHM, o que ocorreu em 40 (95%) dos 42 pacientes. Não encontramos diferença significativa quando comparamos pacientes com haste visualizada e não visualizada quanto à freqüência de partos vaginais em apresentação pélvica, à freqüência de malformações do SNC e à posição precisa da neuro-hipófise ectópica. Identificamos 6 variações alélicas no gene LHX4 em nossos pacientes: GGT>GGC, no códon 21; GAC>GAT, no códon 128; AAC>AAT, no códon 150; AGC>AGT, no códon 230; GGA>GGT, no códon 283 e AAT>AGT no códon 329 (N329S), esta já descrita como polimorfismo no GenBank. Nenhuma das outras variações determina troca de aminoácidos, altera o sítio de \"splice\" ou se correlaciona com um padrão de deficiência hormonal característico. As variações alélicas nos códons 21, 128 e 150 foram caracterizadas como polimorfismos. Não foi possível estabelecer uma relação entre as variações alélicas e o fenótipo dos pacientes. CONCLUSÃO: Mutações no LHX4 são causas raras de hipopituitarismo / INTRODUCTION: Ectopic posterior pituitary lobe (EPL) is observed using magnetic resonance imaging (MRI) scans in about 40% of patients with hypopituitarism. In these patients, the pituitary stalk is visualized mainly in patients with isolated GH deficiency (IGHD), whilst it is not visualized predominantly in patients with combined pituitary hormone deficiency (CPHD). Nevertheless, the etiology of EPL remains undetermined in most of the patients. A traumatic etiology is proposed for this figure, which presents a high frequency of breech delivery and perinatal damages. On the other hand, a genetic cause is suggested by associations to other CNS abnormalities and reports of gene mutations in HESX1, LHX4 and SOX3, as well as familial cases. LHX4 is a transcription factor implicated in pituitary embryogenesis which is essential to definitive Rathke\'s pouch development. It is located in chromosome 1q25, has 6 exons and is stretched out for more than 45 kb of genomic DNA. The only documented human mutation in this gene, IVS4-1G>C, is associated to a phenotype characterized by short stature, GH, TSH and ACTH deficiencies, EPL and Arnold-Chiari type I malformation. The aim of this study is to analyze exonic and exon-intron regions of LHX4 gene and characterize the hormonal deficiency profiles, establishing relationships to MRI findings in 63 patients with hypopituitarism associated to EPL. METHODS: All patients were submitted to hormonal evaluation and MRI scans. The molecular analysis included amplification of the gene using PCR, direct automatic sequencer and digestion with restriction enzymes. RESULTS: The pituitary stalk was visualized in 21 patients; of these, 10 (48%) exhibited IGHD. The stalk was not visualized in 42 patients, most of them with CPHD (95%). We did not find a statistical difference, when patients with and without visualized pituitary stalk were compared, regarding breech deliveries, CNS malformations and exact position of EPL. We identified 6 allelic variations in LHX4 gene: GGT>GGC in codon 21, GAC>GAT in codon 128, AAC>AAT in codon 150, AGC>AGT in codon 230, GGA>GGT in codon 283 and AAT>AGT in codon 329 (N329S), this already related as a polymorphism in GenBank. None of the former variations determine amino acid changes, nor splicing site changes, not even are related to a typical profile of hormonal deficiency. The allelic variations in codons 21, 128 and 150 were described as polymorphisms. It was not possible to establish a relationship between the allelic variations and the phenotype. CONCLUSION: LHX4 gene mutations are rare causes of hypopituitarism
9

Prevalence of the posterior superior alveolar canal assessed with cone beam computed tomography

Anamali, Sindhura 01 December 2012 (has links)
No description available.
10

Prevention of posterior capsule opacification by photodynamic therapy with localized benzoporphyrin derivative monoacid ring A (BPD-MA) in a rabbit surgical model

Meadows, Howard Earl 11 1900 (has links)
Posterior capsule opacification (PCO) is a major component of secondary cataract, a complication of current cataract surgery practice. This iatrogenic condition occurs in virtually all pediatric cases and to a lesser extent in adults. PCO correlates with the development in the latter half of the 20th Century of extracapsular cataract extraction (ECCE). In these surgeries, the lens capsule is left intact. During ECCE surgery a circular capsulotomy opening is created in the anterior lens capsule, and the cataractous, proteinaceous lens is removed, often via ultrasonic lens liquefaction i.e. phacoemulsification. The posterior, equatorial and remaining anterior portions of the sac-like capsule are left intact, permitting the insertion of an artificial lens into the emptied capsule. However, cells from the monolayer of epithelium on the inner surface of the capsule often begin to proliferate and migrate onto the normally cell-free inner surface of the posterior capsule, and may obscure the central axis of vision. Subsequently, a second surgery is necessary to create a small capsulotomy in the centre of the posterior capsule, usually employing an Nd:YAG laser. However, up to 5% of patients who have capsulotomies may then develop further serious, vision-threatening complications such as macular edema and retinal detachments. This thesis reports the photodynamic therapy (PDT) conditions required to prevent lens epithelial (LE) cell de novo proliferation and migration onto posterior lens capsules in a euthanized rabbit surgical model in order to predict parameters required to prevent PCO in humans. Experiments with primary in vitro cultures of human LE cells have shown rapid delivery of the photosensitizer benzoporphyrin derivative monoacid ring A (BPD-MA) and efficient killing with low light doses of 690 nm red light. Additional studies have shown the efficacy of various viscous agents in protecting the comeal endothelium. During model phacoemulsification ECCE surgeries, the use of hyaluronate viscoelastic carriers addressed the need for containment necessary for localized delivery of photosensitizer in the emptied capsule. Long-term monitoring of PDT-treated rabbit lens capsules in vitro has demonstrated a phototoxic effect including complete cell kill in this surgical model employing the prophylactic use of PDT.

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