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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.
81

Rekonstrukce krevního řečiště prstu ve 3D z videosekvence / Reconstruction of the Bloodstream of the Finger in 3D from a Video Sequence

Záleský, Jiří January 2020 (has links)
The goal of the master thesis is the design and construction of a device for capturing video sequences of the cardiovascular system of the finger of a human hand and the subsequently design and implementation of a method of data extraction for its reconstruction into a 3D model.
82

Hepatic capacitance reponses to changes in flow and hepatic venous pressure in dogs

Bennett, Tom D. January 1980 (has links)
This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).
83

Development of a Hybrid, Finite Element and Discrete Particle-Based Method for Computational Simulation of Blood-Endothelium Interactions in Sickle Cell Disease

Blakely, Ian Patrick 10 August 2018 (has links)
Sickle cell disease (SCD) is a severe genetic disease, affecting over 100,000 in the United States and millions worldwide. Individuals suffer from stroke, acute chest syndrome, and cardiovascular complications. Much of these associated morbidities are primarily mediated by blockages of the microvasculature, events termed vaso-occlusive crises (VOCs). Despite its prevalence and severity, the pathophysiological mechanisms behind VOCs are not well understood, and novel experimental tools and methods are needed to further this understanding. Microfluidics and computational fluid dynamics (CFD) are rapidly growing fields within biomedical research that allow for inexpensive simulation of the in vivo microenvironment prior to animal or clinical trials. This study includes the development of a CFD model capable of simulating diseased and healthy blood flow within a series of microfluidic channels. Results will be utilized to further improve the development of microfluidic systems.
84

Novel vascular markers and therapeutic strategies for the prevention of vein graft failure in a pig model of carotid artery-saphenous vein interposition grafting.

January 2009 (has links)
Kang, Ning. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references. / Abstract also in Chinese. / Abstracts --- p.i / Abbreviations --- p.v / List of Figures and Tables --- p.vii / Contents --- p.viii / Chapter Chapter 1: --- Introduction --- p.1 / Chapter 1. --- Saphenous vein graft patency after coronary artery bypass grafting --- p.1 / Chapter 2. --- Mechanism of vein graft failure and therapeutic strategies --- p.8 / Chapter 2.1 --- Mechanism --- p.15 / Chapter 2.2 --- Therapeutic strategies --- p.18 / Chapter 3. --- Summary --- p.22 / Chapter 4. --- References --- p.23 / Chapter Chapter 2: --- Animal model and laboratory investigations --- p.34 / Chapter 1. --- Surgical procedure --- p.35 / Chapter 2. --- Postoperative management --- p.37 / Chapter 3. --- Adenoviral-mediated gene transfer ex vivo for gene therapy study --- p.38 / Chapter 4. --- Laboratory investigations --- p.39 / Chapter 5. --- Statistical analysis --- p.40 / Chapter 6. --- Summary --- p.41 / Chapter 7. --- References --- p.41 / Chapter Chapter 3: --- "Impact of osteopontin expression in vein grafts on VSMC migration, proliferation, and neointimal formation" --- p.42 / Chapter 1. --- Introduction --- p.42 / Chapter 2. --- Methods and materials --- p.43 / Chapter 3. --- Results --- p.43 / Chapter 4. --- Discussion --- p.49 / Chapter 5. --- Summary --- p.52 / Chapter 6. --- References --- p.53 / Chapter Chapter 4: --- Potential Role of gene therapy in prevention of vein graft failure --- p.56 / Chapter 1. --- Vectors --- p.56 / Chapter 2. --- "Reporter gene, timing and titer" --- p.57 / Chapter 3. --- Candidate genes --- p.58 / Chapter 4. --- Summary --- p.64 / Chapter 5. --- References --- p.66 / Chapter Chapter 5: --- Conclusions --- p.70 / Acknowledgements --- p.72
85

Vein and replacement type Sn and Sn-W mineralization in the Southern Kaoko Zone, Damara Province, South West Africa/Namibia

Petzel, V January 1986 (has links)
The ENE trending Brandberg West - Goantagab Sn-W belt is located in the Southern Kaoko Zone of the northern coastal branch of the Damara Orogen. The lithologies in this area are turbiditic and consist of three schist units separated by two marble horizons, all of which are correlated with the Swakop Group. The formations are intensely folded by at least three episodes of which the first two are coaxial and resulted in prominent, approximately N-S trending, structures. Sn and Sn-W mineralization predominantly occurs as vein and replacement type mineralization. Vein type mineralization occurs as Brandberg West, Frans Prospect, Gamigab Prospect and the Goantagab Mining Area. The vein type mineralization is accompanied by intense alteration, consisting of greisenization, sericitization, hematitization and carbonatization. Replacement-type, hematite-cassiterite mineralization, occurs in the Goantagab Mining area in the marble close to, or at the schist marble contact. Intense ferruginous alteration of the marbles in this area, is associated with veins, which terminate against, or cross cut the marble. A regional metal zonation, ranging from Sn-W mineralization with minor sulphides at Brandberg West to Sn-sulphide mineralization at Goantagab can be detected. This metal zonation is attributed to the distance of the mineral locality from the source area, with Goantagab representing a distal and Brandberg West a proximal position relative to the source area. Structural, mineralogical and geological features of the mineralization in this area suggest that processes of ore genesis may be related to anorogenic magmatism of Karoo age.
86

Rozpoznávání člověka podle žil prstu / Human Recognition by Finger Veins

Lisák, Peter January 2011 (has links)
The master's thesis deals with biometric systems, especially these based on human recognition by finger veins. It describes some development principles of the new biometric system. It proposes some new approaches to the comparison of finger vein patterns and their fast identification in sizable databases. Verification is based on templates comparison by similarity and distance measures with proposed alignment approaches. The proposed method of identification is based on the combination of clustering and genetic algorithm. The second option is using the indexing tree structure and searching by range query.
87

Lifestyle and clinical factors related to the deterioration of trunk varicose veins, telangiectasia, chronic venous insufficiency and venous reflux in the general population : Edinburgh Vein Study follow-up

Boghossian, Sheila January 2014 (has links)
Venous disease is a common vascular condition affecting the lower limbs and causes considerable morbidity in affected patients. National Health Service (NHS) treatment costs are substantial and there is a large demand for treatment much of which cannot be met. Roughly half a million people in the United Kingdom contact their general practitioner each year about varicose veins and associated clinical symptoms. In order to assign priorities and target interventions properly, authorities need to know which patients with venous disease will progress. Although many epidemiological studies have investigated the prevalence of venous disease, information on deterioration is scarce. The overall aim of this study is to determine the natural history of venous disease in the population and to identify lifestyle and clinical factors related to deterioration which might aid clinical decision making and health services policy. The specific objectives were to determine which risk factors were associated with deterioration of venous disease and venous reflux, and to ascertain the natural history of asymptomatic venous incompetence in terms of deteriorating to overt trunk varicose veins and chronic venous insufficiency. The study design was a population based cohort in the Edinburgh Vein Study which the survivors of the 1566 individuals aged 18 to 64 randomly sampled years from the general population at baseline underwent a 13-year follow-up examination. Details of the 1566 participants in the baseline study were sent to the Practitioner Services Division (PSD) of the NHS in Scotland who provided updated addresses and general practitioner registration details. Information collected on each subject at a follow-up clinic included lifestyle factors and medical history, height and weight measurement (by means of a questionnaire), clinical examination for classification of venous disease according to the Basle and CEAP systems, and duplex scanning to assess incompetence of venous valves in the deep and superficial systems of ten vein segments in each leg. Of the subjects from the baseline, 880 participated in the follow-up study, and 576 did not participate, providing a response rate of 60.4% of which 490 were female (55.7%) and 390 were male (44.3%). The study subjects were generally older and slightly more affluent than residents of the City of Edinburgh. For trunk varicose veins, the baseline prevalence was higher in males compared to females (p<0.01), but there was no difference in prevalence among subjects at the follow-up stage of the study (p=0.56). The overall rate of deterioration in trunk varicose veins was 3.55% per annum. More females than males deteriorated (p=0.04). Among subjects who showed deterioration in their trunk varicose veins, the commonest deterioration was from Basle Grade I (mild) at baseline to Grade II (moderate) at follow-up in both the right and left leg (28.1% and 32.9% respectively). Subjects older than 55 years of age (OR=1.59, 95% CI 1.01-2.51), who had a positive family history of varicose veins or venous ulcer (OR=1.92, 95% CI 1.20-3.07), and sat down at work for more than half the working day (OR=1.69, 95% CI 1.04-2.73) had increased risk of deteriorating trunk varicose veins. There was no significant difference between males and females in the prevalence of chronic venous insufficiency (CVI) among subjects at both the baseline and follow-up stage of the study (p=0.15 and 0.16 respectively). The rate of deterioration in CVI was 1.76% per annum. Similarly, among subjects who deteriorated, the commonest deterioration was from Grade I (mild) to Grade II (moderate) CEAP classification in both the right and left leg (42.4% and 45.5% respectively). The risk of worsening of CVI among those older than 55 was nearly three times more than those aged less than 55 (OR=2.85, 95% CI 1.18-6.87), and was still significant when adjusted for gender. The prevalence of telangiectasia was higher in females than in males in both the baseline and follow-up stages of the study (both p<0.01). The rate of deterioration in telangiectasia was 1.6% per annum. The commonest deterioration was from grade I (mild) at baseline to grade II (moderate) follow-up in the left and right leg (using the Basle Classification). Females subjects (OR=1.87, 95% CI 1.35-2.64), those older than 55 (OR=1.68, 95% CI 1.19-2.36), with a positive family history of venous disease (OR=1.60 95% CI 1.14-2.24) were associated with an increased risk of deterioration from telangiectasia compared to male subjects under 55 years of age and with no family history of the disease. The risk of telangiectasia deterioration was more than twice as high in subjects with venous reflux in the greater saphenous vein (origin) (OR=2.34, 95% CI 1.53-3.57), the greater saphenous vein (lower third of the thigh) (OR=2.28, 95% CI 1.59-3.27) and in the small saphenous vein (1.89, 95% CI 1.06-3.36) compared to those with no segments affected. The age and gender adjusted risk was also more than twice as high in subjects with venous reflux in two segments of the superficial system compared to subjects with no venous reflux in any segment (OR=2.06, 95% CI 1.23-3.44), and almost four times as high in subjects with reflux in more than three segments of the superficial system (OR=3.97, 95% CI 2.16-7.31) compared to subjects with no segments affected. On duplex scanning, the prevalence of reflux was higher in females than in males in the superficial system at baseline and follow-up stages of the study (p<0.01 respectively). In the deep system, the prevalence was higher in males than females at the baseline stage (p<0.01) with no significant difference at the follow-up stage (p=0.85). The rate of deterioration in venous reflux was 1.28% per annum. Most subjects deteriorated from one to two vein segments affected in the leg, the majority of which had reflux in the greater saphenous vein (thigh) at baseline and developed reflux in the greater saphenous vein (origin) at follow-up. Subjects more than 55 years of age had significantly more deterioration than those aged less than 55 (p<0.01). Obese or overweight subjects (OR=1.59, 95% CI 1.32-3.67), those aged more than 55 (OR=2.20, 95% CI 1.32-3.67), with a family history of varicose veins (among female subjects only, OR=2.55, 95% CI 1.16-5.56), and who sat down at work more than half the working time (among male subjects only) (OR=2.26, 95%CI 0.97-5.23) had increased risk of showing deterioration in reflux in any leg and in any vein segment from baseline to follow-up. Subjects with venous reflux at baseline were over two and half times more likely to show deterioration in trunk varicose veins compared to those with no reflux (OR=2.69, 95%CI 1.44-5.01), and four times more likely to deteriorate in either trunk varicose veins or chronic venous insufficiency (OR=4.20, 95% CI 2.42-7.29). Subjects with venous reflux at baseline were twice as likely to develop new trunk varicose veins (OR=2.08, 95%CI 1.25-3.46), and 1.78 times more likely to develop either trunk varicose veins or chronic venous insufficiency (OR=1.78, 95%CI 1.12-2.80). Age and gender adjusted risk of trunk varicose veins increased more than fourfold among subjects with venous reflux in the greater saphenous veins (OR=4.04, 95% CI 2.36-6.92), and more than threefold in the greater saphenous vein (lower third of the thigh) (OR=3.13, 95% CI 1.85-5.27) and the small saphenous vein (OR=3.17, 95% CI 1.55-6.48). Subjects with venous reflux in two or more than three vein segments in the superficial system were more than five times more likely to deteriorate from trunk varicose veins (OR=5.39, 95% CI 2.64-10.99 and OR=5.96, 95% CI 2.71-13.10 respectively). The Edinburgh Vein Study follow-up identified factors linked to deterioration of trunk varicose veins and CVI. The findings of this follow-up study have important implications in decision making in NHS and a prognostic tool could be produced to assist clinicians in deciding who should receive treatment or maintained under surveillance. Increasing age, and family history will likely lead to worsening of trunk varicose veins and CVI. The findings also confirm the association between asymptomatic and symptomatic venous valvular incompetence with worsening and developing new cases of venous disease. Such information will be essential for policy makers facing difficult decisions over prioritisation of services in the future. Further research might include trials of surgical and non-surgical interventions designed to limit deterioration in high risk individuals and enable surgeons to target interventions appropriately. Larger prognostic studies of many factors, including genotype, might be conducted to link progression of venous disease, and to provide further information on high risk individuals who might benefit from treatment.
88

Venous haemodynamic and cerebrospinal fluid anomalies associated with multiple sclerosis

Beggs, Clive Barron January 2014 (has links)
This critical synopsis of prior work by Clive Beggs is submitted in support of a PhD by published work. The work focuses on venous and cerebrospinal fluid (CSF) anomalies associated with multiple sclerosis (MS) and other neurological diseases. MS is characterized by focal inflammatory lesions, which are often venocentric. Recently a vascular syndrome, chronic cerebrospinal venous insufficiency (CCSVI) has been linked with MS. This syndrome, which is characterized by constricted cerebral venous outflow, has become mired in controversy, with various studies producing conflicting findings, with the result that the science associated with CCSVI has become obscured. Clive Beggs work seeks to bring clarity to the debate surrounding CCSVI by characterizing physiological changes associated with constricted cerebral venous outflow. The work submitted here involves collaborative studies with Robert Zivadinov (University of Buffalo), Paolo Zamboni (University of Ferrara), and Chih- Ping Chung (National Yang Ming University of Medicine). The key findings of these studies are: (i) MS patients, diagnosed with CCSVI, exhibit greatly increased hydraulic resistance of the cerebral venous drainage system; (ii) MS patients experience loss of the small cerebral veins; (iii) MS patients exhibit reduced CSF bulk flow, consistent with mild venous hypertension; (iv) MS patients exhibit increased CSF pulsatility in the Aqueduct of Sylvius, which appears to be linked with mild venous hypertension associated with CCSVI; and (v) jugular venous reflux is associated with white matter and parenchymal volumetric changes in Alzheimer’s patients. Collectively, these findings suggest that extracranial venous anomalies are associated with changes in the intracranial physiology.
89

Ablação por radiofreqüência da fibrilação atrial paroxística: fatores determinantes da eficácia clínica a longo prazo / Radiofrequency catheter ablation of paroxysmal atrial fibrillation: decisive factors of the clinical efficacy in long-term.

Sartini, Raul José Pádua 30 May 2007 (has links)
O objetivo deste estudo foi avaliar retrospectivamente, em longo-prazo, os preditores de recorrência de fibrilação atrial paroxística (FA) em 139 pacientes submetidos à ablação por radiofreqüência, através das técnicas ostial ou extraostial de abordagem do átrio esquerdo, associadas ou não à ablação do istmo cavo-tricuspídeo (ICT). Variáveis pré, intra e pós-ablação foram avaliadas por análise uni e multivariada, para determinar os preditores de recorrência da FA após um procedimento. Observou-se que maior tempo de história de FA, uso de mais antiarrítmicos e recorrência de FA dentro de 60 dias pós-procedimento, aumentaram o risco de recorrência de FA a longo-prazo. Por outro lado, a associação de flutter atrial e a ablação concomitante do ICT, reduziram o risco de recorrência ao final de 33 ±12 meses. / The objective of this study was to evaluate in retrospect, in long-term, the predictors of late recurrence of atrial fibrillation (AF) in 139 patients submitted to the ablation by radiofrequency, through the techniques ostial or extra-ostial of approach of the atrium left, associated or not to the ablation of the cavotricuspid isthmus(ICT). Variables pre, intra and post-ablation were appraised for analysis uni and multivariated, to determine the predictors of recurrence of AF after one procedure. It was observed that larger time of history of AF, use of more drugs and recurrence of AF within 60 days after procedure; they increased the risk of recurrence of AF in long-term. On the other hand, the association of atrial flutter and the concomitant ablation of ICT, they reduced the recurrence risk at the end of 33 ±12 months.
90

Doppler venoso fetal na insuficiência placentária: relação com o pH no nascimento / Fetal venous Doppler in pregnancies with placental dysfunction: correlation with pH at birth

Ortigosa, Cristiane 18 April 2012 (has links)
OBJETIVO: O presente estudo, realizado em gestantes de alto risco com diagnóstico de insuficiência placentária, tem como objetivo avaliar o fluxo sanguíneo fetal na veia portal esquerda (VPE), veia umbilical (VU) e ducto venoso (DV), e estabelecer quais parâmetros associam-se com a acidemia fetal no nascimento. MÉTODO: Pesquisa prospectiva envolvendo 58 gestantes, classificadas segundo a presença ou ausência do diagnóstico de acidemia no nascimento, de acordo com o pH no sangue da artéria umbilical, constituindo-se de: Grupo I: 26 casos (acidemia pH<7,20) e Grupo II: 32 casos (pH normal pH7,20). Foram excluídos da pesquisa os casos com diagnóstico pós-natal de anomalia do RN e aqueles em que não se obteve a mensuração do pH no nascimento. As seguintes variáveis dopplervelocimétricas da VPE e VU foram comparadas entre os grupos: escore-zeta da TAMxV (time averaged maximum velocity) (cm/s), Q/Kg (fluxo sanguíneo por Kg de peso fetal) (ml/min/kg) e presença de pulsatilidade; e o escore-zeta do índice de pulsatilidade para veias (IPV) do DV. RESULTADOS: O escore-zeta da TAMxV (rho=0,392, P=0,002) e o Q/Kg da VPE (rho=0,274, P=0,037), o escore-zeta do IPV do DV (rho=-0,377, P=0,004) e o Q/Kg da VU (rho=0,261, P=0,048) apresentaram correlação significativa com o pH no nascimento. Realizando-se a análise de regressão logística multivariada, as variáveis independentes que restaram no modelo final para a ocorrência de acidemia no nascimento (pH<7,20) foram: escore-zeta da TAMxV da VPE (OR=0,41; IC95% 0,25 a 0,71; P=0,001) e fluxo reverso na VPE (OR=0,004; IC95% 0,00 a 0,15; P=0,003), ambas demonstrando efeito protetor para acidemia. Com o presente modelo, constatou-se que 74,1% dos casos são corretamente classificados para acidemia no nascimento. CONCLUSÕES: pela análise do Doppler venoso fetal na insuficiência placentária constatou-se que a acidemia no nascimento (pH<7,20) está associada de forma independente com o fluxo reverso na VPE e com o escore-zeta da TAMxV da VPE, ambos demonstrando efeito protetor com redução do risco para a acidemia / OBJECTIVE: This study, conducted in high-risk pregnancies with placental insufficiency, aims to avaliate blood flow in the fetal left portal vein (LPV), umbilical vein (UV) and ductus venosus (DV), and establish which parameters are associated with acidemia at birth. METHOD: A prospective research involving 58 pregnant women, classified according to the presence or absence of the diagnosis of fetal acidosis at birth, according to pH in the blood of the umbilical artery, consisting of: Group I: 26 cases (acidemia, pH <7,20) and Group II: 32 cases (normal pH, pH 7,20). Exclusion criteria were patients who had postnatal diagnosis of abnormality of the newborn and those in which the pH measurement was not obtained at birth. The following Doppler variables of LPV and UV were compared between the groups: TAMxV (Time Averaged Maximum Velocity) (cm/s) zeta-score, Q/kg (blood flow per kg of fetal weight) (ml/min/kg) and presence of pulsatility; and DV pulsality index for veins (PIV) zetascore. RESULTS: LPV TAMxV zeta-score (rho=0.392, P=0.002) and Q/kg (rho=0.274, P=0.037), DV PIV zeta-score (rho=-0.377, P=0.004) and UV Q/kg (rho=0.261, P=0.048) showed significant correlation with pH at birth. Performing the multivariate logistic regression analysis, the independent variables that remained in the final model were: TAMxV of LPV zeta-score (OR=0.41; IC95% 0.25 a 0.71; P=0.001) and reverse flow in LPV (OR=0.004; IC95% 0.00 a 0.15; P=0.003), both showing a protective effect to reduce the risk of acidemia. With this model, it was found that 74,1% of cases are correctly classified to birth acidemia. CONCLUSION: by analysis of fetal venous Doppler in placental insufficiency we found that acidemia at birth (pH <7.20) is independently associated with reverse flow in the LPV and LPV TAMxV z-score, both showing a protective effect with reduced risk for the event

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