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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.
11

INVESTIGATION OF THE BIOTRANSFORMATION OF 4-(METHYLNITROSAMINO)-1-(3-PYRIDYL)-1-BUTANONE BY PROSTAGLANDIN H SYNTHASE AND CYTOCHROME P450 2F

Fikree, Hana M. 15 January 2008 (has links)
The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is believed to play a role in human lung cancer induced by tobacco smoking. NNK biotransformation may involve the enzymes prostaglandin H synthase (PHS)-1, PHS-2 and cytochrome 450 (CYP) 2F. PHS activity is thought to be important in extrahepatic tissues, where CYP activity is low. The CYP2F subfamily contains a single functional enzyme in humans (CYP2F1) and goats (CYP2F3); these enzymes are preferentially expressed in the lung, with little or no expression in other organs. The role of these enzymes in the pulmonary biotransformation of NNK was investigated. 4.2 µM [5-3H]NNK was incubated with human lung microsomes under NADPH-dependent and arachidonic acid-dependent conditions. Metabolites reflective of NNK α-carbon hydroxylation, N-oxidation and carbonyl reduction were detected in the presence of NADPH, and metabolite levels for all three biotransformation pathways were lower in the presence of arachidonic acid compared with NADPH (p<0.05, N=4). Incubation of microsomes with the PHS-1 selective inhibitor SC-560 and the PHS-2 selective inhibitor NS-398 did not change NNK biotransformation either in the presence of NADPH or in the presence of arachidonic acid (p>0.05, N=4). Incubation of [5-3H]NNK with ovine PHS-1 or PHS-2 did not result in formation of α-carbon hydroxylation or N­-oxidation metabolites; 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) was measurable only in the presence of PHS-2. Incubation of goat recombinant CYP2F3 with [5-3H]NNK resulted in formation of keto acid, keto alcohol and NNK-N-oxide (65.0%, 17.5% and 30.0% (µmol enzyme)-1 minute-1, respectively). Metabolite formation was inhibited by 3-methylindole (3-MI), a mechanism-based inactivator of CYP2F3. Based on an N value of 3, incubation of human lung microsomes with 3-MI inhibited N-oxidation (p<0.05) but did not alter NNK bioactivation or carbonyl reduction (p>0.05). However, when metabolite formation was examined in lung microsomes from different individuals, decreases in NNK biotransformation (ranging from 19.6 to 68.5%) were observed and were more pronounced in some patients than others, suggesting inter-individual variability in CYP2F1 activity. These studies demonstrate the ability of CYP2F to biotransform NNK and suggest inter-individual variability in the importance of CYP2F1 for this activity in human lung. They also strongly argue against the involvement of PHS enzymes. / Thesis (Master, Pharmacology & Toxicology) -- Queen's University, 2007-12-30 16:12:58.228
12

Impact of the Human Lung Mucosa on <i>Mycobacterium tuberculosis</i> Infection of Alveolar Epithelial Cells

Scordo, Julia Marianna January 2018 (has links)
No description available.
13

Einfluss einer vorhergehenden Influenza A Virus Infektion auf die angeborene Immunität gegenüber der sekundären Pneumokokkenpneumonie in humanem Lungengewebe

Berg, Johanna 13 July 2016 (has links)
Sekundäre bakterielle Infektionen im Verlauf oder in Folge einer Infektion mit Influenza A Viren (IAV) steigern oftmals die Schwere des Krankheitsverlaufes, was besonders während der IAV Pandemien von 1918, 1968 und 2009 deutlich wurde. Genaue mechanistische Ursachen, welche dieser gesteigerten Kopathogenität zugrunde liegen wurden überwiegend in Tierversuchsmodellen adressiert und sind immunologisch unvollständig. Aufgrund organstruktureller und immunfunktioneller Speziesunterschiede ist ungewiss, inwieweit eine Übertragbarkeit der Daten zwischen Mensch und Maus besteht. Fokus der Arbeit bildete die Analyse potentieller IAV assoziierter Änderungen der angeborenen Immunität, welche sekundäre Pneumokokkeninfektionen in humanem ex vivo Lungengewebe begünstigen. Dafür wurden zentrale Zyto - bzw. Chemokine als Reaktion auf Einzelinfektionen mit dem saisonalen IAV Pan/99(H3N2) sowie Streptococcus pneumoniae D39 mit denen subsequenter viral-bakteriellen Koinfektion verglichen. Ausgelöst durch die antivirale Interferonantwort erfolgte die Reduktion der pneumokokkeninduzierten Bildung von IL-1β und GM-CSF auf translationaler und transkriptioneller Ebene. Vermutlich beeinflussen Typ I und II Interferone die IL-1β Bildung, welches über parakrine Wechselwirkungen an der GM-CSF Regulation beteiligt ist. Auf zellulärer Ebene verursachte IAV die Freisetzung von Typ I, II und III Interferonen aus primären humanen Alveolarepithelzellen vom Typ II. In humanen Alveolarmakrophagen unterdrückten Typ I und II Interferone die pneumokokkeninduzierte IL-1β Freisetzung. Folglich unterblieb die IL-1β-regulierte GM-CSF Sekretion aus Alveolarepithelzellen vom Typ II. Die Ergebnisse zeigen, dass influenzainduzierte Interferone durch die Unterdrückung der IL-1β regulierten Bildung von GM-CSF in humanem Lungengewebe beitragen. Damit unterstützt sie das Verständnis immunologischer Faktoren, welche diesem Krankheitsbild im Menschen pathophysiologisch zugrunde liegen können. / Secondary bacterial infections, which occur during or following an IAV infection, exaggerate the severity of the course of disease up to a lethal outcome, clearly recognizable during the fatal IAV pandemics from 1918, 1968 or 2009. Particular mechanisms underlying this exaggerated viral-bacterial copathogenity were almost solely addressed using animal models and are immunologically incomplete. Due to structural and immunofunctional interspecies differences the transferability of data between human and mice remains indeterminate. The study mainly purposed to investigate IAV associated modulations of innate immunity, which potentially facilitates secondary pneumococcal pneumonia in primary human ex vivo lung tissue. Hence secretion of central cyto- and chemokines initiated by single infection with the seasonal IAV Pan/99(H3N2) or the bacterium Streptococcus pneumoniae D39 were compared to subsequent viral-bacterial coinfection. In context of an antiviral interferon response the pneumococcal induced translation and transcription of IL-1β and GM-CSF were reduced. Probably type I and type II interferons affect generation of IL-1β, which participates in the regulation of GM-CSF by paracrine interactions. On a cellular basis the infection of primary human alveolar epithelial cells type II (AECII) with IAV triggered the release of interferon type I, II and III. In human alveolar macrophages type I and II interferons suppressed the pneumococcal induced release of IL-1β. Consequently, the IL-1β regulated generation of GM-CSF in AECII was impeded. The present study indicates, that influenza related induction of interferons suppresses the IL-1β related release of GM-CSF in human lung tissue. Thereby it takes part in contributing to pathophysiological comprehension of immunological factors underlying this copathogenity.
14

Untersuchung des Infektionsverhaltens verschiedener respiratorischer Viren in humanem ex vivo kultiviertem Lungengewebe

Becher, Anne 23 September 2015 (has links)
Mechanismen, die zur unterschiedlichen Pathogenität niedrig- und hochpathogener aviärer und humanpathogener Influenzaviren im Menschen beitragen, sind bisher nur ansatzweise verstanden. Auch sind Pathomechanismen, die der Middle East Respiratory Syndrome (MERS)-CoV-Infektion zu Grunde liegen, bisher weitgehend unbekannt. In dieser Arbeit wurde ein humanes ex vivo Lungenkulturmodell für die Untersuchung der Influenzavirus- und der MERS-CoV-Infektion etabliert. Dabei wurde die Replikationsfähigkeit und der Zelltropismus der Viren systematisch verglichen. Während hochpathogene aviäre, saisonale und pandemische Influenzaviren effizient in der humanen Lunge replizierten, konnten sich niedrigpathogene aviäre Viren und ein porcines Virus kaum vermehren. Alle Viren zeigten jedoch den gleichen Zelltropismus und infizierten im Alveolarepithel ausschließlich Typ II Zellen. Die unterschiedliche Pathogenität dieser Viren lässt sich daher nicht durch Unterschiede im Zelltropismus erklären. Gleichwohl konnte der humane und der aviäre Influenzavirusrezeptor sowohl auf Typ II als auch auf Typ I Zellen nachgewiesen werden. Niedrigpathogene aviäre Influenzaviren sind in der humanen Lunge durch die Freisetzung von zum größten Teil nicht infektiösen Viruspartikeln restringiert. MERS-CoV replizierte in humanem Lungengewebe mit ähnlicher Kinetik wie ein hochpathogenes H5N1 Virus. MERS-CoV Antigen war sowohl im Bronchialepithel, Alveolarepithel sowie im Endothel nachweisbar. Der funktionelle Rezeptors des MERS-CoV, die Dipeptidylpeptidase 4, wurde in allen infizierten Zelltypen sowie in Alveolarmakrophagen nachgewiesen. Die mikroskopische Analyse infizierter Gewebeproben weist zudem auf einen infektionsbedingten Alveolarschaden hin. Die Studie trägt wesentlich zum pathophysiologischen Verständnis pulmonaler Influenzavirus- und MERS-CoV-Infektionen bei. Das humane ex vivo Lungenkulturmodell stellt ein klinisch relevantes Modell zur Untersuchung respiratorischer Infektionen im Menschen dar. / Mechanisms contributing to the different pathogenicity of low and highly pathogenic avian and seasonal influenza viruses in humans are currently only partially understood. Furthermore, underlying pathological mechanisms of the Middle East Respiratory Syndrome (MERS)-CoV infection in humans are widely unknown. In this study a human ex vivo lung culture model was established, which allowed investigating influenza virus and MERS-CoV infection. Replication and cellular tropism of the different viruses were compared systematically. While highly pathogenic avian, seasonal and pandemic influenza viruses replicated efficiently, low pathogenic avian viruses and a porcine virus propagated poorly. However, all viruses showed the same cellular tropism and infected only type II cells within the alveolar epithelium. Therefore, the different pathogenicity of these viruses cannot be attributed to different cellular tropisms. Nevertheless, the human and the avian influenza virus receptor could be detected on type II and type I cells. Low pathogenic avian influenza viruses are restricted in the human lung by the release of mostly non-infectious progeny virus particles. The MERS-CoV replicated with similar kinetics to a highly pathogenic H5N1 virus in the human lung. MERS-CoV antigen was detected in the bronchial epithelium, alveolar epithelium and endothelium. The functional receptor of MERS-CoV, dipeptidylpeptidase 4, was found in all infected cell types and in alveolar macrophages. Microscopic analysis of infected tissue samples indicated an alveolar damage provoked by MERS-CoV infection. This study contributes substantially to the pathophysiological understanding of the pulmonary influenza virus and MERS-CoV infection. The human ex vivo lung culture model represents a clinically relevant model to investigate human respiratory infections.
15

Vergleichende Analyse saisonaler, aviärer, porziner und pandemischer Influenzaviren in humanen Lungen- und Zellkulturen

Weinheimer, Viola 19 December 2011 (has links)
Das Auftreten des pandemischen H1N1-Influenzavirus 2009 und die kontinuierliche Übertragung hochpathogener H5N1-Viren (HPAIV) auf den Menschen verdeutlichen die Wichtigkeit zoonotischer Übertragungen. Bis heute sind die Restriktion tierpathogener Influenzaviren und die hohe Virulenz der HPAIV im Menschen nicht vollständig geklärt. Verschiedene Modelle wurden zur Studie von Influenzaviren verwendet, u. a. Zelllinien, die jedoch die Komplexität und Zelltypen der humanen Lunge nur unzureichend wiedergeben. Daher wurde ein humanes ex vivo Lungenkulturmodell etabliert in welchem die komplexe Struktur und die verschiedenen Zelltypen der humanen Lunge erhalten bleiben. Mit Hilfe dieses Modells und primären und permanenten humanen Zellen wurden saisonale, pandemische, porzine, HPAIV und niedrigpathogene aviäre Influenzaviren (LPAIV) systematisch hinsichtlich Replikation, Cytokininduktion und Zelltropismus verglichen. HPAIV replizierten wie auch saisonale und pandemische Viren zu hohen Titern, während sich LPAIV und ein porzines Virus kaum vermehrten. Einhergehend mit dem Vorhandensein aviärer Rezeptoren waren LPAIV dennoch fähig Lungenkulturen und Zellen zu infizieren und es fanden sich keine Unterschiede im Vorhandensein und in der Lokalisation viraler Proteine. Die Infektion mit HPAIV und LPAIV führten im Lungenmodell zu einer erhöhten Induktion von IP10, MIP1β, IFNβ und IL1β, während saisonale und pandemische H1N1-Viren nur geringe Cytokinspiegel hervorriefen. Trotz der hier beobachteten Unterschiede in der Replikation und Cytokininduktion infizierten alle Viren überwiegend Typ II Pneumozyten. Dies impliziert, dass sich die gezeigten Unterschiede zwischen saisonalen und aviären Viren nicht durch Unterschiede im Zelltropismus erklären lassen. Die im Rahmen dieser Studie erzielten Ergebnisse korrelieren gut mit klinischen Beobachtungen. Dies verdeutlicht den Wert humaner ex vivo Kulturen um weitere Einblicke in das pathophysiologische Verhalten von Pathogenen zu bekommen. / The emergence of the pandemic H1N1 influenza A virus in 2009 and the continuous threat by highly pathogenic avian H5N1 human infections underlines the importance of zoonotic transmissions. The inability of most animal influenza viruses to replicate efficiently in the human respiratory tract and the high virulence of highly pathogenic avian H5N1 viruses (HPAIV) are still not fully understood. Several models have been used to study influenza virus infections including human cell lines that lack the complexity and cell diversity of the human lung. Therefore, a human lung explant model in which the three-dimensional structure of the human lung is preserved along with the different cell-cell interactions was established. Using this model and commonly used primary and permanent respiratory cells, replication, cytokine induction and cell tropism of human, avian, swine and pandemic 2009 virus was systematically compared. It was shown that HPAIV as well as seasonal and pandemic 2009 viruses replicated to high titers while a low pathogenic avian (LPAIV) or a classical swine virus only replicated inefficiently. However, along with the presence of avian receptors, LPAIV was able to infect human lung explants and cells and there were no differences in abundance and localization of proteins. Infection of human lung explants with the HPAIV and LPAIV lead to a pronounced induction of IP10, MIP1β, IFNβ and IL1β while seasonal and pandemic 2009 viruses caused only a low cytokine response. Despite their differences in replication and cytokine induction, LPAIV and the seasonal virus both primarily targeted type II pneumocytes suggesting that the observed differences between the two viruses are not due to differences in cell tropism in the human lower respiratory tract. The experimental findings obtained in this study are compatible with clinical observations highlighting the value of ex vivo human lung explants to provide insights into viral pathophysiological behavior in humans.
16

Strategies towards the synthesis of 4-(3-methyl-but-1-enyl)-3,5,3',4'-tetrahydroxystilbene (arachidin-1) and resveratrol analogues

Olusegun-Osoba, Elizabeth Oluwakemi January 2015 (has links)
Stilbene phytoalexins such as resveratrol, 1, and the arachidins, including arachidin-1,2, are naturally synthesised by peanut (Arachis hypogaea) plants. The peanut phytoalexins are polyphenolic compounds consisting of a stilbene backbone, with a number of derivatives also possessing a prenyl moiety. These distinctive phytoalexins have gained attention, as they exhibit various biological activities, for instance arachidin-1, 2, has been reported to be more potent than resveratrol, 1, in the inhibition of lipopolysaccharide-induced expression of cyclooxygenase-2 (COX-2) and COX-2 mRNA, in vitro at doses that were low in cytotoxicity. Additionally the various arachidins have recently been shown to exhibit their anti-inflammatory properties, through the inhibition of a number of inflammatory mediator pathways. In this work, various routes into the synthesis of arachidin-1, 2, are described, via use of the Horner-Wadsworth-Emmons (HWE) reaction. Three different methodologies were explored, the first approach involving silyl ether (TIPS or TBDMS) protected benzaldehydes, proved unsuccessful due to cleavage of the silyl ether protecting groups, in basic and/or acidic conditions. This led to an alternative approach, whereby formation of the stilbene backbone proceeded via the regioselective demethylation of an acetal in the presence of sodium metal, subsequent electrophilic substitution using iodomethane and finally acetal hydrolysis of the acetal, gave the isolated aldehyde in moderate yield (52 %). Coupling of the aldehyde with the substituted benzylphosphonate, via the HWE reaction gave the desired trans-stilbene in good yield (86 %), however incorporation of the prenyl side chain proved to be challenging via the Wohl-Ziegler bromination. Further adaptation of the aforementioned route, whereby alkylation using diethyl iodomethylphosphonate, enabled the incorporation of the prenyl moiety and the subsequent construction of the trans-stilbene backbone, gave the 4-(3-methyl-but-1- enyl)-3,5,3',4'-tetramethoxystilbene, 3, albeit in poor yield (47 %). The final step involving demethylation using BBr3 gave arachidin-1, 2, also in poor yield (30 %), nevertheless this approach has been proved to be a successful route for the total synthesis of arachidin-1, 2, however optimised studies are required in order to obtain the desired compound in quantitative yields. Synthetic analogues of resveratrol, 1, are also known for their biological activities, including anti-inflammatory and chemopreventative properties. Recently, the anti-proliferative activity of a number of stilbenesulfonamides, against the National Cancer Institute's 60 (NCI-60) human tumour cell line has been reported. Furthermore, the anti-inflammatory effects of novel heterocyclic methylsulfone and sulfonamide analogues, via inhibition of the COX-2 protein have also been published, however both synthetic routes described require a total of six or seven steps, from the sulfanilamide and are limited to the synthesis of primary sulphonamides (SO2NH2). In this work, an efficient three step synthesis has been designed and successfully implemented, proceeding via chlorosulfonation of diethyl benzylphosphonate, to form the sulfonyl chloride intermediate. Aminolysis of the sulfonyl chloride intermediate was then performed, using a range of primary, secondary and cyclic alkyl amines, as well as aromatic amines; including ammonia, dimethylamine, morpholine and diphenylamine. Finally, formation of the stilbene backbone with various substituted aldehydes, via the HWE reaction offered a short, versatile and alternative route to the synthesis of novel primary, secondary and tertiary trans-stilbene benzenesulfonamides and heterocyclic analogues, in yields of 42 - 100 %. The activity of a selection of the synthesised stilbene benzenesulfonamides was evaluated against the human lung adenocarcinoma epithelial cell line (A549). Amongst the compounds tested, analysis of the data showed that the novel analogue, 4, was found to be the most potent compound, with a GI50 of 0.1 μM. Comparison with the previously published data found analogue, 4, to be approximately 500-fold more potent than the lead compound resveratrol, 1, (GI50 = 51.64 μM) and approximately twice as potent than 5-fluorouracil (GI50 = 0.189μM), a chemotherapy drug used to treat various forms of cancer 8. Overall, these results demonstrate that the total synthesis of trans-arachidin-1, 2, can be achieved via a five step methodology. A versatile route to the synthesis of novel stilbene benzenesulfonamides has also been successfully achieved, amongst the compounds synthesised one appears to show promising anticancer activity, and warrants further investigation (i.e. in vitro studies using other cancer cell lines, and the synthesis of additional compounds using analogue, 4, as a lead compound).
17

Exploration du microbiote respiratoire humain / Human respiratory microbiota exploration

Mbogning Fonkou, Maxime Descartes 22 November 2018 (has links)
L'établissement d'un répertoire exhaustif ainsi que son élargissement constituent les deux objectifs principaux de ce travail. Nous avons d'abord établi la toute première liste de bactéries identifiées par culture des voies respiratoires au travers de la littérature scientifique. Nous répertorions ici 756 espèces, ce qui représente 27,23% de l'ensemble des bactéries isolées chez l'homme lorsque comparé au répertoire établi récemment par Bilen et al. Parmi ces bactéries, 514 avaient déjà été isolées au moins une fois dans les poumons. Plus de la moitié (i.e., 65,5%) des bactéries isolées pour la première fois dans des échantillons de poumons, ont été identifiées après les années 2000, soulignant la nécessité de poursuivre les efforts pour cultiver des microbes à partir des échantillons de voies respiratoires. Nous pensons que la combinaison de méthodes de culture à grande échelle telles que la culturomique et la métagénomique aidera à mieux décrire le microbiote pulmonaire. Des études antérieures sur le microbiote digestif le démontre. Nous avons ensuite utilisé des approches culturomiques et métagénomiques pour explorer le microbiote respiratoire d'individus sains. Nous avons isolé 193 bactéries par culturomics. Parmi ceux-ci, nous avons ajouté 84 au répertoire du microbiote respiratoire, dont 14 nouvelles espèces. En utilisant des approches métagénomiques, 139 OTU identifiées au rang de l'espèce dont seulement 49 (17,3%) étaient également retrouvées par culturomique, confortant la complémentarité des deux approches. Enfin, nous avons utilisé la taxonogénomique, une nouvelle approche permettant la description de nouvelles espèces bactériennes, pour décrire 19 bactéries. / The establishment of a comprehensive directory and its expansion through the use of high-speed culture methods are the two main objectives of this thesis work. We first established the first list of bacteria identified by airway culture through the scientific literature. Here we list 756 species, representing 27.23% of all bacteria isolated from humans when compared to the recently established repertoire of Bilen et al. Of these bacteria, 514 had already been isolated at least once in the lungs. Considering bacteria isolated for the first time in lung samples, more than half (ie, 65.5%) were identified after the 2000s, highlighting the need for continued efforts to grow microbes from lane samples respiratory. We believe that the combination of large scale culture methods such as culturomics and metagenomics will help to better describe the pulmonary microbiota. Previous studies on the digestive microbiota have shown the complementarity of these two approaches. We then used culturomic and metagenomic approaches to explore the respiratory microbiota of healthy individuals. We isolated 193 bacteria by culturomics. Of these, we added 84 bacteria to the repertoire of the respiratory microbiota, including 14 new species discovered. Using metagenomic approaches, 139 OTUs identified with the rank of the species of which only 49 (17.3%) were also recovered by culturomics, reinforcing the complementarity of the two approaches. Finally, we used taxonogenomics, a new approach for describing new bacterial species by integrating genomic and proteomic data with those that are classically integrated. Using this approach, 19 bacteria were described as part of this work.
18

Characterization of mass transport in the upper human airways

Bauer, Katrin 22 February 2012 (has links) (PDF)
Mechanical ventilation can be a life saving treatment. However, due to the inhomogeneous and anisotropic behavior of the lung tissue, ventilation can also lead to overdistensions of lung regions whereas other areas remain even collapsed. A first step is a more comprehensive understanding of the flow mechanics under normal breathing conditions in a healthy lung as well as for a diseased, collapsed lung. This is the aim of this work. Therefore, a realistic model of the upper human airways has been generated at which experimental and numerical investigations could be carried out. Experimentally, the flow was analyzed by means of Particle Image Velocimetry (PIV) measurements which revealed new details about the flow patterns occurring during different ventilation frequencies. Numerical results were in good agreement with the experimental results and could provide new details about the three-dimensional flow structure and emerging secondary flow within the upper airways. The study of reopening of collapsed airways has shown that larger frequencies lead to airway reopening without overdistension of already open parts. Higher frequencies also lead to homogenization of mass flow distribution within the human lung. / Künstliche Beatmung ist meist eine lebensrettende Maßnahme. Aufgrund der räumlich anisotropen und inhomogenen Eigenschaften der Lunge kann die Beatmung jedoch auch zu einer Schädigung der Lunge führen. Daraus ergibt sich die Forderung einer „Protektiven Beatmung“. Ein erster Schritt dahingehend ist ein verbessertes Verständnis der Atmung und Beatmung am Beispiel der gesunden sowie kranken, teilweise kollabierten Lunge. Dies ist das Ziel der Arbeit. Hierfür wurde ein realistisches Modell der oberen Atemwege (Tracheobronchialbaum) angefertigt. An diesem Modell können sowohl experimentelle als auch numerische Untersuchungen durchgeführt werden. Experimentell wurde die Strömung mittels Particle Image Velocimetry (PIV) untersucht, wobei neue Details bezüglich der auftretenden Strömungsmuster für unterschiedliche Frequenzen gefunden wurden. Numerische Strömungsberechnungen stimmen gut mit den experimentellen Ergebnissen überein. Dreidimensionale Strömungsstrukturen sowie die Entwicklung von Sekundärwirbeln in der Lunge konnten erklärt werden. Eine Studie am kranken, teilweise kollabierten Lungenmodell zeigte, dass mit steigender Frequenz kollabierte Bereiche wiedereröffnet werden können. Höhere Frequenzen führen weiterhin zu einer Homogenisierung der Massenstromverteilung in der Lunge.
19

Modeling nitric oxide production and transport in the human lung

Kerckx, Yannick 09 June 2009 (has links)
Le travail présenté ici porte sur l’étude de la production et du transport du monoxyde d’azote (NO) dans le poumon humain. Le NO est une molécule dont l’implication dans des processus physiologiques n’a été mis en évidence qu’en 1987. Depuis, il a été démontré que le NO joue de nombreux rôles dans le corps humain. Le NO est un gaz labile (instable) dans les conditions physiologiques, il diffuse très facilement au travers des parois et il a une grande affinité pour l’hémoglobine. La production du NO est liée à 3 isoformes différentes de la protéine appelées synthases du NO ou NO synthases.<p>\ / Doctorat en sciences, Spécialisation physique / info:eu-repo/semantics/nonPublished
20

Industry and traffic related particles and their role in human health

Oravisjärvi, K. (Kati) 08 October 2013 (has links)
Abstract Combustion generated ultrafine particles have been found to be responsible for adverse effects on human health. New emission reduction technologies and fuels will change the composition of particle emissions. It is important to confirm that the new reduction technologies are designed to minimise the adverse health effects. In this doctoral thesis the potential health effects caused by traffic and industrially generated particles were studied using epidemiological, experimental and in silico studies. The effects of short-term changes in PM2.5 on the respiratory health of symptomatic children living near a steel works were studied to investigate whether specific sources of PM2.5 have the possible health effects. The PM2.5 emission sources were identified: long-range transport, a steel works, soil and street dust and a mechanical engineering works. Significant associations were not found between respiratory symptoms and PM2.5 or the sources markers. The deposition of traffic-related particles into the human respiratory system was computed using the lung deposition model. Particle size distribution was measured from diesel- and compressed natural gas (CNG)-fuelled busses and an off-road diesel engine under different combustion situations. The majority of the measured traffic-related particle numbers reach the alveolar region of the lungs. There were differences in the deposition of particles when different catalysts, engines or fuels were used. CNG or a diesel particulate filter (DPF) significantly reduced lung exposure to particles. Also physical activity, age and gender affected the deposition of particles. The diesel particles comprised compounds (carcinogenic PAHs, transition metals), which may have the ability to generate reactive oxygen. This study provides new knowledge how of the emission abatement technologies and fuels affects particle number and their composition, as well health hazards. Cleaner technology (CNG, DPF), emits significantly fewer particles in numbers, especially large particles, but they emit high amounts of small-size particles, which penetrate most easily to the deepest parts of the lungs. In addition, particles from engines with DPF include the largest variety of transition metals and other hazardous compounds compared to combustion systems having different emission after-treatment units. / Tiivistelmä Palamisprosesseista peräisin olevien ultrapienten hiukkasten on todettu olevan haitallisia ihmisen terveydelle. Uudet pako- ja savukaasujen puhdistusteknologiat ja polttoaineet vaikuttavat hiukkaspäästöihin ja niiden koostumukseen. Uusien menetelmien käytön tulee vähentää hiukkasten mahdollisia terveyshaittoja. Tässä väitöskirjassa tutkittiin liikenteestä ja teollisuudesta peräisin olevien hiukkasten mahdollisia terveyshaittoja käyttäen epidemiologista, kokeellista ja in silico- menetelmiä. Työssä tutkittiin PM2.5-hiukkasten lyhytaikaisvaihtelun yhteyttä terästehtaan läheisyydessä asuvien hengitystieoireisten lasten terveyteen ja päästölähteiden yhteyttä mahdollisiin terveysvaikutuksiin. Merkittäviä PM2.5-päästölähteitä olivat kaukokulkeuma, terästehdas, maaperä ja tiepöly sekä konepaja. Tutkimuksessa ei havaittu lasten hengitystieoireiden ja PM2.5:n tai päästölähteiden merkkiaineiden välillä merkittävää yhteyttä. Liikenneperäisten hiukkasten kulkeutumista ihmisen hengitysteihin tutkittiin keuhkodepositiomallilla. Diesel- ja maakaasukäyttöisten (CNG) bussien ja dieselkäyttöisen työkoneen hiukkaskokojakaumat mitattiin eri palamisolosuhteissa. Suurin osa mitatuista hiukkaslukumääristä kulkeutui keuhkojen alveolaaritasolle. Erilaisten katalysaattorien, moottoreiden tai polttoaineiden käytön seurauksena hiukkasten lukumääräpitoisuudet vaihtelivat ja siten hiukkasten kulkeutumisessa hengitysteihin oli eroja. CNG:n tai hiukkassuodattimen (DPF) käyttö vähensi merkittävästi hiukkaslukumääriä ja keuhkojen altistumista hiukkasille. Myös liikunta, ikä ja sukupuoli vaikuttivat hengitysteihin kulkeutuvien hiukkasten määriin. Dieselhiukkaset sisälsivät yhdisteitä (karsinogeeniset PAH:t, siirtymämetallit), jotka tuottavat hengitysteissä reaktiivisia happiradikaaleja. Tämä tutkimus antaa uutta tietoa päästövähennysmenetelmien ja polttoaineiden vaikutuksista hiukkasten lukumäärään ja koostumukseen sekä hiukkasten terveyshaitoihin. Puhtaamman teknologian käyttö (CNG, DPF) vähentää huomattavasti pakokaasun hiukkasten lukumäärää, etenkin suurten hiukkasten, mutta tuottaa silti suuria määriä pieniä hiukkasia, jotka kulkeutuvat helpommin keuhkojen syvimpiin osiin. Lisäksi moottoreiden hiukkaspäästöt käytettäessä hiukkassuodatinta, sisälsivät enemmän erilaisia siirtymämetalleja ja muita haitallisia aineita verrattuna polttoon, jossa käytettiin muita päästöjen jälkikäsittelymenetelmiä.

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