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Rôle du monoxyde d'azote dans la calcification vasculaire et la rigidité artérielle dans un modèle d'hypertension systolique isoléeGilbert, Liz-Ann 12 1900 (has links)
L’hypertension systolique isolée (HSI) est le résultat de changements au niveau de la paroi vasculaire qui ont pour conséquence d’augmenter la rigidité artérielle. Ces modifications surviennent surtout au niveau des grosses artères comme l’aorte et sont associées au vieillissement. La fragmentation des fibres élastiques, leur calcification (élastocalcinose) et la fibrose font partie des changements majeurs observés avec l’âge. En plus de ces changements, le vieillissement vasculaire provoque des modifications au niveau des cellules qui composent la paroi. Les cellules endothéliales sécrètent moins de monoxyde d’azote (NO) provoquant une dysfonction endothéliale et les cellules musculaires lisses vasculaires (CMLVs) synthétisent maintenant des protéines matricielles et osseuses.
Situé entre le sang et les CMLVs, l’endothélium contrôle le tonus vasculaire par la sécrétion de plusieurs substances vasoactives qui interagissent entre elles afin de maintenir l’homéostasie du système vasculaire. Parmi celles-ci, on note l’endothéline (ET), un puissant vasoconstricteur et le NO, un gaz vasorelaxants. Ce dernier est aussi reconnu pour bloquer la production d’ET par un mécanisme dépendant du guanosine monophosphate cyclique (GMPc). Comme il y a une interaction entre le NO et l’ET, et que cette dernière est impliquée dans la calcification artérielle, le NO pourrait être impliqué dans la modulation de l’élastocalcinose et de la rigidité artérielle par l’inhibition de l’ET et la modification de la composition de la paroi. Cet effet, qui se produirait au delà des effets vasorelaxants du NO, offre un potentiel thérapeutique intéressant pour l’HSI.
Afin d’évaluer l’implication du NO dans la calcification vasculaire et la rigidité artérielle, un modèle animal d’HSI a été utilisé (modèle warfarine vitamine K, WVK). Ce modèle d’élastocalcinose est basé sur l’inhibition de la maturation d’une protéine anti-calcifiante, la matrix Gla protein (MGP), par la warfarine.
Afin de déterminer l’implication physiologique du NO dans l’initiation et la progression de l’élastocalcinose, sa production a été inhibée par un analogue de la L-arginine, le L-NG-nitroarginine methyl ester (L-NAME). Lors des processus d’initiation de la calcification, le L-NAME a prévenu l’élastocalcinose sans toutefois modifier la vitesse de l’onde de pouls (PWV). Suite au traitement L-NAME, l’expression de la NO synthase inductible (iNOS) a été diminuée alors qu’elle a été augmentée lors du traitement WVK. Elle pourrait donc être impliquée dans les processus de calcification vasculaire. De plus, la NO synthase endothéliale (eNOS) semble également impliquée puisqu’elle a été augmentée dans le modèle WVK. Cette hausse pourrait être bénéfique pour limiter l’élastocalcinose alors que l’expression de la iNOS serait délétère. Lors de la progression de la calcification, le L-NAME a augmenté l’élastocalcinose et le PWV. Dans ce contexte, l’ET serait impliquée dans l’amplification de la calcification vasculaire entrainant une hausse de la rigidité artérielle. Comme le NO endogène limite la progression de la calcification et conséquemment la rigidité artérielle, il semble être protecteur.
L’efficacité d’une modulation de la voie du NO dans le modèle WVK a été étudiée par l’administration d’un donneur de NO, le sinitrodil, ou d’un inhibiteur de la phosphosdiestérase 5 (PDE5), le tadalafil. La modulation de la voie du NO semble être bénéfique sur la rigidité artérielle, mais seulement de façon aiguë. En effet, le sinitrodil a modifié de transitoirement la rigidité au niveau de l’aorte possiblement par la modulation du tonus vasculaire sans toutefois avoir des effets sur la composition de la paroi. Comme le modèle WVK n’affecte pas la fonction endothéliale, les concentrations endogènes de NO semblent être optimales puisque le sinitrodil provoque une augmentation de l’élastocalcinose possiblement par le développement d’une tolérance. Tout comme le sinitrodil, le tadalafil a modulé de manière aiguë la rigidité artérielle sans modifier la composition de la paroi.
Globalement, ces travaux ont permis de mettre en évidence les effets bénéfiques du NO endogène pour limiter le développement de l’HSI, suggérant qu’une dysfonction endothéliale, tel qu’observé lors du vieillissement, a un impact négatif sur la maladie. / Isolated systolic hypertension (ISH) is the result of complex changes in the vascular wall and consequently the increase of arterial stiffness. These modifications occur mainly in conductance arteries, like the aorta, and are associated with aging. The fragmentation of elastic fibers, calcification (elastocalcinosis), and fibrosis are major changes with age. In addition to these changes in the extracellular matrix, vascular aging also induces vascular cell wall modifications. These include decreased production of nitric oxide (NO) by endothelial cells, which induces endothelial dysfunction, and the production of matrix and bone proteins by vascular smooth muscle cells (VSMCs).
Located between the blood and VSMCs, the endothelium controls vascular tone by secreting various vasoactive factors. These factors interact with each other to maintain the hemodynamic of the vascular system. Among these factors, the vasoconstrictor endothelin (ET) and the vasodilator NO. The latter has been shown to block ET production via a cyclic guanosine monophosphates-(cGMP) dependent mechanism, whereas ET has been implicated in arterial calcification. Therefore, NO might be involved in the modulation of elastocalcinosis and arterial stiffness by inhibiting ET and modifying the vascular wall composition. This effect of NO could offer interesting therapeutic potential for ISH.
To evaluate the implication of NO in the vascular calcification and arterial stiffness, an animal model of ISH was used. This model of elastocalcinosis is based on the inhibition of the maturation of the anti-calcific protein, matrix Gla protein (MGP), by warfarin (WVK model).
To gain insight into the physiological role of endogenous NO in the initiation and progression of elastocalcinosis, its production was inhibited by the administration of L-NAME. Interestingly, elastocalcinosis was prevented by L-NG-nitroarginine methyl ester (L-NAME) administration without any modifications of the pulse wave velocity (PWV) during the initiation of the calcification processes. After the L-NAME treatment, the expression of inducible NO synthase (iNOS) was decreased, whereas upon treatment with warfarin alone the expression of iNOS was increased, which could be implicated in vascular calcification and arterial stiffness. In addition, endothelial NO synthase (eNOS) seems to be implicated in this process as its expression was also increased upon WVK treatment. This increase could be beneficial to limit elastocalcinosis, whereas the increase in iNOS expression could be harmful. L-NAME administration during the progression of calcification increased elastocalcinosis and PWV. In an endothelial dysfunction context, ET has been shown to be involved in the amplification process of vascular calcification causing an increase in arterial stiffness. As NO limits the progression of calcification and consequently arterial stiffness, endogenous NO seems to be protective in the aorta.
The efficacy of exogenous modulation of the NO pathway in the WVK model was studied upon administration of the NO donor, sinitrodil, or the phosphodiesterase type 5 inhibitor (PDE5), tadalafil. The exogenous modulation of the NO pathway seemed to be beneficial for arterial stiffness, but only in an acute manner. Indeed, sinitrodil modified the acute stiffness in the aorta potentially by vascular tone modulation, without having any effect on vascular wall composition. Since endothelial function was not affected upon WVK model, endogenous NO concentrations seem to be optimal. Thus, exogenous NO potentially caused an increase of elastocalcinosis by inducing tolerance to NO. As well as sinitrodil, tadalafil modulated the arterial stiffness in an acute manner without modifying the composition of the vascular wall.
Broadly, these studies provide evidence that endogenous NO can limit ISH development, suggesting that endothelial dysfunction, as observed in aging, has a negative impact on this pathology.
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Charakteristika velkých tepen u primární a sekundární - endokrinní hypertenze / Large artery properties in primary and secondary - endocrine hypertensionRosa, Ján January 2011 (has links)
Arterial stiffness represented by carotid-femoral pulse wave velocity (PWV) is considered to be an independent cardiovascular risk factor. This study was focused on large artery properties investigation in specific forms of hypertension using applanation tonometer Sphygmocor (Atcor Medical). PWV was significantly higher in resistant hypertension patients when compared to moderate essential hypertension (EH) patients. This difference appears to be independent of clinical blood pressure (BP). Night-time BP appears to be a more accurate predictor of PWV in EH. In another study we demonstrated that primary hyperparathyroidism (PH) (both hypertensive or non-hypertensive forms) might be associated with higher PWV when compared to EH patients or to normotensive controls and that this difference is independent of age and clinical BP. Neither calcium serum level, nor parathyroid hormone has been associated with PWV. Specific treatment by parathyroidectomy (PTX) seems to be beneficial for PWV decrease, which might be mainly determined by improved BP control after surgery. Since PTX indications for asymptomatic forms of PH have been discussed, our data suggest the potential benefit to the extent of subclinical organ damage after surgical treatment in these patients. Similarly, we prooved higher PWV in...
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Variações seculares de facies sedimentares de lama da plataforma continental de Cabo Frio (RJ)Cruz, Anna Paula Soares 11 May 2017 (has links)
Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-05-11T16:44:42Z
No. of bitstreams: 1
CRUZ, A. P. S..pdf: 23384634 bytes, checksum: b417fd0517bbafbf4617a53288a634f4 (MD5) / Made available in DSpace on 2017-05-11T16:44:42Z (GMT). No. of bitstreams: 1
CRUZ, A. P. S..pdf: 23384634 bytes, checksum: b417fd0517bbafbf4617a53288a634f4 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / A análise conjugada das propriedades físicas dos se
dimentos, como a velocidade da
onda P, susceptibilidade magnética, porosidade e de
nsidade gama, com propriedades
geoquímicas como Carbono Orgânico Total e mineralog
ia dos sedimentos proporciona uma
melhor avaliação dos processos envolvidos, proveniê
ncia e fluxo de material sedimentar,
permitindo que as mudanças ambientais possam ser de
finidas. Os parâmetros físicos além de
serem capazes de quantificar a distribuição de espa
ço entre os poros, indicam alterações pós-
deposicionais. Dessa forma, este trabalho visa aval
iar as inter-relações existentes entre
parâmetros físicos de seções sedimentares para dete
rminação da origem do fluxo de materiais
ao longo da fácies de sedimentar depositado sobre a
plataforma continental de Cabo Frio.
Nesse sentido, pode-se notar que as variações de Vp
estão ligadas ao tamanho do grão, assim
como ao aumento no conteúdo orgânico e aumento no t
eor de água nos sedimentos marinhos.
Os valores de SM mostraram-se associados a assemblé
ia mineralógica e ao teor de água dos
testemunhos. Além disso, foi possível constatar que
a valência dominante da razão Fe
3+
/Fe
2+
,
foi o de Fe
3+
, que influenciou diretamente nos picos de SM. As p
ropriedades físicas definiram
seções nos diferentes box-core analisados, os quais
o BCCF10-01, 04 e 09, apresentaram
aumento de grãos finos, que pode estar relacionado
a hidrodinâmica local, e/ou aumento de
contribuição sedimentar alóctone entre 100 e 80 ano
s AP. Além disso, a assembléia de
minerais pesados indicou proveniência de rochas met
amórficas derivadas de metassedimentos
siliciclásticos, granitóides, rochas máficas e alca
linas pertencentes a própria região de Cabo
Frio e adjacências. Os maiores teores de minerais e
ncontrados no BCCF10-01 e BCCF10-13,
podem informar sobre a influência de correntes de f
luxo oeste, proveniente da baía de
Guanabara e de correntes de norte, provenientes dos
rios São João e Paraíba do Sul como
principais agentes de transporte dos particulados s
edimentares e minerais para a fácies
sedimentar de lama da plataforma de Cabo Frio. / The combined analysis of the physical properties of
sediments, such as the P-wave
velocity, magnetic susceptibility, porosity and gam
ma-density, with geochemical properties
such as Total Organic Carbon and mineralogy of sedi
ments provides a better assessment of
the processes involved, provenance and sedimentary
material flow, allowing environmental
changes can be defined.
The physical parameters in addition to being able t
o quantify the
distribution of space between the pores also indica
te pos-depositional changes. Thus, this
study aims to evaluate the interrelations between p
hysical parameters of sedimentary sections
to determine the source of the material flow along
the sedimentary faces deposited on the
continental shelf of Cabo Frio.
In this sense, it may be noted that variations in V
p are clearly
linked to the grain size, and an increase in organi
c content and increased water content in
marine sediments.
The MS values were associated with the mineral asse
mblage and water
content of the cores. In addition, it determined th
at the oxidation state of the dominant was
Fe
3+
, which directly influenced the peaks of MS.
Physical properties defined in the different
sections analyzed box-core, which the BCCF10-01, 04
and 09, showed an increase of fine
grains, which can be related to the local hydrodyna
mic or increased allochthonous sediment
contribution between 100 and 80 years BP.
In addition, the heavy mineral assemblage
indicated provenance of metamorphic rocks derived f
rom siliciclastic metasediments,
granitoids, mafic and alkaline rocks belonging to t
he region of Cabo Frio and surrounding
areas.
The highest minerals content found in BCCF10-01 and
BCCF10-13, can showed the
influence of flow west currents, from the Guanabara
Bay and currents of the north, from the
São João and Paraiba do Sul rivers as the main carr
iers of sedimentary particles and mineral
from mud faces of the Cabo Frio Shelf.
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Influencia da dimensão do corpo-de-prova no ensaio destrutuvo de compressão paralela as fibras e no ensaio não-destrutivo utilizando ultra-som / Influence of the specimen size on destructive methods of parallel compression grain and on the test non-destructive using ultra sonic wavesTrinca, Alex Julio 22 February 2006 (has links)
Orientador: Raquel Gonçalves / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-07T23:01:52Z (GMT). No. of bitstreams: 1
Trinca_AlexJulio_M.pdf: 4149749 bytes, checksum: 34fcccdf02d4f1b0b171e121e4eb5ac3 (MD5)
Previous issue date: 2006 / Resumo: é praticamente toda exportada em sua forma in natura sem que a ela seja agregado valor de beneficiamento. Um dos problemas enfrentados pela indústria moveleira é o fato da madeira não ser submetida à classificação, dificultando a elaboração de projetos e a certificação da qualidade do móvel confeccionado a partir deste material. Nesse contexto as empresas moveleiras brasileiras buscam parâmetros para composição e certificação de seu produto, sendo atualmente a norma brasileira ¿Projeto de Estruturas de Madeira¿ ¿ NBR 7190/97, o único instrumento norteador para a caracterização de propriedades da madeira. No entanto, nesse setor as dificuldades para a obtenção de corpos-de-prova nas dimensões especificadas por esse texto normativo têm gerado dúvidas quanto aos resultados de caracterização de propriedades, de maneira que este trabalho teve como objetivo principal verificar se os valores do módulo de elasticidade e da tensão de ruptura no ensaio de compressão paralela às fibras podem ser considerados estatisticamente equivalentes, desde que sejam mantidas a proporcionalidade da dimensão do corpo-de-prova. Para isso adotou-se, como alternativa ao corpo-de-prova proposto pela NBR 7190/97, a dimensão 0,03 m x 0,03 m x 0,09 m. Os ensaios foram realizados utilizando-se 7 diferentes espécies de madeira com densidades variadas, buscando-se, com essa amostragem, a generalização dos resultados. Como objetivo secundário se buscou avaliar a influência das dimensões do corpo-de-prova e da freqüência do transdutor na velocidade de propagação de ondas de ultra-som na direção longitudinal. As espécies adotadas foram: Cerejeira (Torresea sp), Perobinha (Paratecoma peroba) , Cabreúva-vermelha (Myroxylon peruiferum), Angico-preto (Anadenanthera macrocarpa), Garapeira (Apuleia leiocarpa), Eucalipto grandis ( Eucalyptus grandis) e Pinus elliotti (Pinus elliottii). Todos os corpos-de-prova foram ensaiados com aproximadamente 12% de umidade e os ensaios foram realizados em ambiente controlado (21° C ± 1°C). Os resultados permitiram concluir que a hipótese foi verdadeira para todas as espécies estudadas quando se considera a tensão de ruptura / Abstract: Most of the exported wood in Brazil is unprocessed, without any aggregated value. To change this scenario technology for wood processing and qualification are required. One of the problems faced by the furniture industry refers to the non classification of the wood, which cause difficulties to projects elaboration and quality certification of the furniture made from this material. In this context the Brazilian Industries of furniture seek for parameters to certificate its products, and the NBR 7190/97 standard ¿Project of Structures of Wood " is, nowadays, the only instrument for the characterization of wood properties. However, for the furniture industry it is very difficult to obtaining the dimensions specified by the standard. This research had as main objective to verify if the means values of the modulus of elasticity and rupture in compression parallel to the grain can be considerate statistically equal, when smaller specimen are used, if the proportionality is maintained. For that it was adopted, as alternative to the specimen proposed by NBR 7190/97, the dimension 0.03 x 0.03 x 0.09 m. For the experiments there were used 7 different species with varied densities. The secondary objective was to evaluate the influence of the specimen size and of the transducer frequency in the speed of ultrasound wave propagation in the longitudinal direction. The adopted species were: Cerejeira (Amburana cearensis), Perobinha (Paratecoma peroba), Cabreúva vermelha (Myroxylon peruiferum), Angico-preto (Anadenanthera macrocarpa), Garapeira (Apulleia leiocarpa), Eucalyptus grandis, (Eucalyptus grandis) and Pinus ellioti (Pinus elliottii). All specimens were tested with approximately 12% moisture content and were accomplished in controlled atmosphere (21° C ± 1°C). The results allowed concluding that the hypothesis was true for all the studied species when the rupture in compression parallel to the grain was considered. For the module of elasticity this hypothesis was not confirmed for two species, from the seven evaluated (garapeira e eucalipto). Although, the mean difference between the results obtained in the tests using both specimens size was 10%, smaller then the maximum allowed variability in mechanical tests (18%). For the ultrasonic velocity propagation four species did not presents statistical variation with the modification of the size of the specimens - cerejeira, garapeira, pinus and eucalyptus while for the perobinha, angico and cabreúva the ultrasonic wave velocity propagation could not be considered statistically equal when the dimension of the specimens was modify. On average (considering all the studied species) the relationship among the ultrasonic wave velocity propagation (VLL) in normalized specimen and in proposed specimen was 0.99, being respectively the maximum and the lower relationships of 1.02 and 0.93. The velocity of wave propagation presents larger variations for values of length of wave percolation/wave length (L/?) up to 3, being more constant above that limit. It was also possible to verify, for the studied species, that the velocity of wave propagation increases with the increase of the transducer frequency. Key words: modulus of elasticity of wood; compression strength parallel to the fiber; ultrasonic wave velocity; dynamic constant / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Agrícola
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Metabolické a genetické faktory cévního stárnutí / Metabolic and Genetic Factors of Vascular AgeingGelžinský, Július January 2021 (has links)
Arterial system is a system of vessels distributing blood. Ageing of arterial system leads to two distinct pathologies: atherosclerosis and arteriosclerosis - stiffening of arterial wall. These pathologies can coexist and interfere; however, they differ in their pathogenesis, location, scope and consequences. Progressive loss of elastic properties of large arteries is natural part of vascular ageing. It is directly responsible for several age dependent consequences, such as increase of central systolic pressure or prevalence of isolated systolic hypertension in the elderly. Clinically, central arteries stiffness manifests as aortic pulse wave velocity, which can be quantified, among other methods, using applanation tonometry. There is abundant evidence that aortic pulse wave velocity represents an independent predictor of cardiovascular mortality and morbidity. The most important mechanism in arterial stiffening is repeated mechanical damage which leads to fractures, fragmentation and thinning of elastin. Stiffening of large arteries can be accelerated by several other mechanisms, e.g. deposition of several substances (calcium, advanced glycation end-products, etc.), metabolic turnover of key elements of vascular extracellular matrix (collagen and elastin) or individual genetic susceptibility. In...
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Vyhodnocení variability rychlosti pulzové vlny / Analysis of pulse wave velocity variabilityBenešová, Lenka January 2019 (has links)
This diploma thesis deals with the variability of pulse wave velocity. It studies the variability of cardiovascular signals. It presents the research of measurement of pulse wave velocity and its analysis in physiology and pathological physiology. Applies spectral analysis in Matlab to a data set. It evaluates and reviews the results of this analysis
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Ein präventivmedizinisches Konzept zur Untersuchung der kardiovaskulären GesundheitSimon, Peter 10 November 2017 (has links)
Kardiovaskuläre Erkrankungen spielen eine immer dominanter werdende Rolle als Ursachen von Morbidität und Mortalität. Endotheliale Dysfunktion, Arteriosklerose und ischämische Herzerkrankungen sind unangefochten die häufigsten Todesursachen in hochentwickelten Ländern. Die Krankheitslast kardiovaskulärer Erkrankungen wird durch die globale Zunahme von Risikofaktoren wie Übergewicht, metabolischem Syndrom und Diabetes mellitus Typ 2 in Zukunft wohl weiter steigen. Keines der in der heutigen Form existierenden Gesundheitssysteme ist den gesundheitlichen Folgen dieser bedenklichen epidemiologischen Entwicklung gewachsen, ohne dafür beträchtliche Einschnitte in Qualität oder Quantität hinnehmen zu müssen. Präventivmedizinische Strategien haben im Vergleich zur Akutmedizin bisher eine wesentlich geringere Aufmerksamkeit erfahren. Aufgrund der weiterhin steigenden Krankheitslast werden gerade präventivmedizinische Strategien immer wichtiger. Die Ermittlung der individuellen kardiovaskulären Gesundheit beinhalten neben einer Untersuchung wichtiger physiologsicher Kernsysteme, einen besonderen Fokus auf die Stärkung der gesundheitlichen Eigenverantwortung durch Vermittlung entsprechender medizinischer Zusammenhänge. Dies kann durch geeignete und prognostisch wertvolle Untersuchungsmethoden und laienverständliche Interpretationen der komplexen kardiovaskulären Zusammenhänge realisiert werden. Mithilfe eines besseren Verständnisses für die eigene kardiovaskuläre Gesundheit und gezielter konkreter Hilfestellungen von ärztlicher Seite, können grundlegende Strukturen für einen achtsameren Umgang mit der eigenen Gesundheit geschaffen werden. Alltägliche körperliche Aktivität, Körperzusammensetzung, Gefäßsteifigkeit und die maximale Leistungsfähigkeit bilden aktuellen Studien zufolge vier relativ einfach zu erhebend Hauptdeterminanten kardiovaskulärer Gesundheit mit großer prädiktiver Vorhersagekraft für kardiovaskulärer Ereignisse. Die Einordnung der Untersuchungsbefunde unter Berücksichtigung altersentsprechender Referenzdaten bietet zusätzlich die Möglichkeit, chronologisches und biologisches Alter zu differenzieren. Darüber hinaus könnte das hier vorgestellte Untersuchungskonzept ebenso dafür eingesetzt werden, die Effektivität von zuvor eingeleiteten therapeutischen Strategien zu überprüfen und eine Übermedikation zu vermeiden. Ein stärkerer Fokus auf nachhaltige kardiovaskuläre präventivmedizinische Strategien birgt das Potential Morbidität und Mortalität zu Reduzieren und die Lebensqualität und Selbstbestimmung der Klienten zu steigern. / Nowadays endothelial dysfunction, arteriosclerosis and ischaemic heart disease depict major issues in most developed countries. Chronic diseases cause an increasing number of deaths worldwide. Responsible for approximately 30% of all deaths, this number is shocking despite the knowledge that these lives could be saved in a realistic point of view. However, disturbing global tendencies and the increase in epidemic overweight, obesity, glucose intolerance and diabetes mellitus type 2 seem to amplify cardiovascular diseases and deaths. No existing medical care system could ever sufficiently match these emergent burdens of global chronic diseases if these tendencies will continue to grow. Due to fatal epidemiological changes general practitioners will not only have to treat more diseases of elderly people, but also be the first contact person for enquiries about their health concerning the cardiovascular systems of younger and older generations. Strengthening prevention concerning cardiovascular diseases is probably the most efficient and only way to escape the vicious circle of pathophysiological processes. To implement cardiovascular prevention it is essential to focus on cardiovascular health rather than on cardiovascular disease. In order to master this challenge sufficiently a deliberate concept of preventive examinations for cardiovascular health is required to quantify cardiovascular wellness and sharpen the awareness of one’s health. Therefore, it is to establish precise, predictive and cost-efficient examination methods to quantify cardiovascular health and subclinical changes at early stages of a disease. Broader acceptance of the preventive potential and the use of modern technological advances could therefore be a powerful instrument to solve the growing global problem of chronic diseases. In this context the routine evaluation of daily physical activity, body composition, arterial stiffness and the maximum physical performance could be a starting point for a preventive diagnostic approach. They can serve as future parameters reflecting health, detecting subclinical diseases and encouraging people’s responsibility for their own health. Detailed information about the major cardiovascular parameters opens specific and efficient course of action to create multiple strategies for gaining or rehabilitating cardiovascular wellbeing
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Charakteristika velkých tepen u primární a sekundární - endokrinní hypertenze / Large artery properties in primary and secondary - endocrine hypertensionRosa, Ján January 2011 (has links)
Arterial stiffness represented by carotid-femoral pulse wave velocity (PWV) is considered to be an independent cardiovascular risk factor. This study was focused on large artery properties investigation in specific forms of hypertension using applanation tonometer Sphygmocor (Atcor Medical). PWV was significantly higher in resistant hypertension patients when compared to moderate essential hypertension (EH) patients. This difference appears to be independent of clinical blood pressure (BP). Night-time BP appears to be a more accurate predictor of PWV in EH. In another study we demonstrated that primary hyperparathyroidism (PH) (both hypertensive or non-hypertensive forms) might be associated with higher PWV when compared to EH patients or to normotensive controls and that this difference is independent of age and clinical BP. Neither calcium serum level, nor parathyroid hormone has been associated with PWV. Specific treatment by parathyroidectomy (PTX) seems to be beneficial for PWV decrease, which might be mainly determined by improved BP control after surgery. Since PTX indications for asymptomatic forms of PH have been discussed, our data suggest the potential benefit to the extent of subclinical organ damage after surgical treatment in these patients. Similarly, we prooved higher PWV in...
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Correlación entre el número de golpes N60 del Ensayo de Penetración Estándar y la Velocidad de ondas de corte (Vs) para los suelos arenosos del distrito de Juliaca – Puno / Correlation between the number of blows N60 of the Standard Penetration Test and the velocity of shear waves (Vs) for the sandy soils of the Juliaca district - PunoAlata Rodriguez, Jair Angelo, Zevillanos Ninancuro, Wilfredo 08 April 2021 (has links)
La aplicación del ensayo de penetración estándar (SPT) conlleva a un nivel de detalle alto, así mismo es costosa, requiere de mano de obra calificada para su ejecución y es demorada; su utilización es recomendada en suelos arenosos, restrictiva en suelos finos y plásticos y no recomendada en los demás tipos de suelos. Mientras que en el Análisis multicanal de ondas superficiales (MASW) su ejecución no se restringe, permite abarcar grandes áreas en tiempos cortos, no obstante, es un método indirecto, razón por la cual su aplicación debe ser verificada mediante perforaciones, obtención de muestras, y altos criterios de análisis. En los últimos años la implementación y mejoramiento de las técnicas de prospección de suelos ha permitido investigar la relación de dichos ensayos con diferentes parámetros del suelo.
En la presente se desarrolló una correlación empírica entre los ensayos geotécnicos SPT mediante el número de golpes de resistencia a la penetración (N60) con el valor de las velocidades de ondas de corte (Vs) de los ensayos geofísicos MASW, se realizaron en 30 puntos del distrito de Juliaca para los suelos arenosos. Se contó con un filtro final de 110 pares ordenados de datos (Vs; N60); mediante el análisis de regresión potencial por el método de mínimos cuadrados donde se obtuvo la ecuación: Vs = 81.079*N600.2646; y un coeficiente de determinación R2:0.76. Esta ecuación fue puesta en análisis comparativo con las ecuaciones de las correlaciones de la literatura, en el cual se encontró una tendencia acorde a las mismas, lo que permitirá utilizarla con suelos afines a la región. / The application of the standard penetration test (SPT) entails a high level of detail, it is also expensive, requires qualified labor for its execution and is time-consuming; Its use is recommended in sandy soils, restrictive in fine and plastic soils and not recommended in other types of soils. While in the multichannel analysis of surface waves (MASW) its execution is not restricted, it allows covering large areas in short times, however, it is an indirect method, which is why its application must be verified by drilling, obtaining samples, and high analytical criteria. In recent years, the implementation and improvement of soil prospecting techniques has made it possible to carry out studies of the relationship of said tests with different soil parameters.
In the present, an empirical correlation was developed between the SPT geotechnical tests by means of the number of penetration resistance blows (N60) with the value of the shear wave velocities (Vs) of the MASW geophysical tests, these tests were carried out in 30 points in the city of Juliaca for sandy soils. There was a final filter of 110 ordered pairs of data (Vs; N60); Through the analysis of potential regression by the method of least squares, the equation was obtained: Vs = 81.079*N600.2646; of the determination coefficient R2:0.76, it was determined that the correlation is acceptable. This equation was put into analysis and comparison with the equations of the correlations of the literature, in which it was found in a trend according to them. / Tesis
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La fissuration thermique dans les roches / Thermal microcracking in rockGriffiths, Luke 23 February 2018 (has links)
Lorsqu'elle est chauffée, la roche peut subir une microfissuration thermique, qui influence ses propriétés physiques, mécaniques, thermiques, et de transport. La surveillance de la microfissuration thermique en laboratoire a été principalement réalisée pendant le chauffage, et rarement lors du refroidissement ou du chauffage cyclique que la roche subit dans les volcans et les réservoirs géothermiques. Un nouvel appareil a été élaboré pour surveiller les émissions acoustiques et mesurer les vitesses des ondes élastiques à haute température. L'état de fissuration a été évalué grâce à un nouvel algorithme d'analyse microstructurale, et l'influence des microfissures sur les propriétés des roches a été mesurée et modélisée. Selon la microstructure, la microfissuration peut avoir lieu pendant le chauffage ou le refroidissement, et les microfissures existantes peuvent s’ouvrir et se fermer de façon réversible avec des changements de température, et influencer les propriétés de la roche. / Rock may undergo thermal microcracking when heated, affecting its physical, mechanical, thermal, and transport properties. Thermal microcrack monitoring in the laboratory has mainly been performed during heating, and rarely during the cyclic heating and cooling relevant for volcanoes and geothermal reservoirs. For this, a new dedicated apparatus for the acoustic emission monitoring and wave velocity measurement at high temperatures was elaborated, building on previous designs. Microcrack damage was assessed with a new algorithm for quantitative microstructural analysis, and the influence of thermal microcracks on rock properties was measured and modelled. Depending on the rock type and initial microcrack content, microcracking occurred during either heating, cooling, or neither, and existing microcracks reversibly opened or closed with increasing temperature. In Earth's crust, the evolution of rock properties with temperature may be significant and is determined by the microstructure.
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