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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.
451

Évaluation de l’association entre l’exposition postnatale aux p,p’-DDT et p,p’-DDE et l’indice de masse corporelle chez les enfants japonais

Plouffe, Laurence 12 1900 (has links)
Les enfants sont exposés au p,p’-dichlorodiphényltrichloroéthane (p,p’-DDT) et au p,p’-dichlorodiphényldichloroéthylène (p,p’-DDE) par transfert placentaire et par le lait maternel. Plusieurs études laissent croire que cette exposition pourrait avoir un impact sur l’indice de masse corporelle (IMC) pendant l’enfance. Le but de notre étude était d’évaluer l’association entre l’exposition par le lait maternel et l’IMC des enfants japonais âgés de 42 mois. Nous avons utilisé les données d’une étude pilote (n=290) de la Japan Environment and Children Study (JECS). Le p,p’-DDT et le p,p’-DDE ont été mesurés dans le lait maternel, et les concentrations chez l’enfant ont été estimées pour trois périodes (0-6 mois, 6-12 mois, 12-24 mois) à l’aide d’un modèle de toxicocinétique. Les associations avec l’IMC à 42 mois ont été évaluées à l’aide de modèles de régression linéaire multivariée. Aucune association n’a été observée avec les concentrations de p,p’-DDT mesurées dans le lait maternel, ni avec les concentrations estimées chez les enfants. Des associations positives avec les concentrations de p,p’-DDE estimées ont été observées chez les filles. Chaque augmentation d’un logarithme naturel dans les concentrations estimées était associée avec une augmentation du score z de l’IMC de 0.23 (I.C. 95% : 0.01, 0.45) pour la période d’exposition 0-6 mois, de 0.26 (I.C. 95% : 0.06, 0.47) pour la période 6-12 mois, et de 0.24 (I.C. 95% : 0.05, 0.43) pour la période de 12-24 mois. Ces associations étaient dans le même ordre de grandeur que l’association observée dans une méta-analyse publiée récemment (augmentation du score z de l’IMC de 0.13 par augmentation d’un logarithme naturel dans l’exposition prénatale), ce qui supporte l’hypothèse que l’exposition développementale au p,p’-DDE est associée avec une augmentation de l’IMC durant l’enfance. / Children are exposed to p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT) and p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE) through placental and lactational transfer. Studies have revealed that these exposures could lead to increased body mass index (BMI) during childhood. Our aim was to assess whether exposure through breast milk is associated with BMI in Japanese children at 42 months of age. We used data from a pilot study (n=290) of the Japanese Environment and Children Study (JECS). p,p’-DDT and p,p’-DDE levels were measured in breast milk, and levels in children were estimated using a toxicokinetic model for three exposure periods (0-6 months, 6-12 months, 12-24 months). Associations with BMI at 42 months of age were assessed using multivariate linear regression models. Our study revealed no significant association with levels of p,p’-DDT measured in breast milk or estimated in children. Positive associations with p,p’-DDE were found in girls during all exposure periods. For each log increase in the estimated p,p’-DDE levels, BMI z-score increased by 0.23 (C.I. 95%: 0.01, 0.45) for the 0-6 months exposure period, 0.26 (C.I. 95%: 0.06, 0.47) for the 6-12 months exposure period and 0.24 (C.I. 95%: 0.05, 0.43) for the 12-24 months exposure period. Our results in girls were similar to those found in a previous meta-analysis that included boys and girls (BMI z-score increase of 0.13 by log increase in prenatal p,p’-DDE levels), supporting that early-life exposure to p,p’-DDE may be associated with increased BMI during childhood.
452

Funktionelle Konnektivität der Substantia nigra in einem generellen Aufmerksamkeitstest bei idiopathischem Stottern – eine klinische Studie mittels funktioneller Magnetresonanztomografie / Functional connectivity of the substantia nigra in a continuous performance test in persistent developmental stuttering – a clinical study using functional magnetic resonance tomography

Metzger, Friederike Luise 10 November 2020 (has links)
No description available.
453

Muscarinic Cholinergic Modulation of Neuronal Excitability and Dynamics via Ether-a-go-go-Related Gene Potassium Channel in Rodent Neocortical Pyramidal Cells

Cui, DongBo 26 August 2019 (has links)
No description available.
454

Nachweis von Salmonella und Yersinia enterocolitica im persistent infizierten Schwein

Arnold, Thorsten 16 October 2002 (has links)
Die Infektion mit Salmonella und Yersinia (Y.) enterocolitica über Produkte tierischen Ursprungs stellt nach wie vor ein ungelöstes Problem des gesundheitlichen Verbraucherschutzes dar. Will man diese Zoonoseerreger aus der Lebensmittelkette fernhalten, sind moderne und gut validierte Nachweissysteme erforderlich. Eine Infektion von Schweinen erfolgt überwiegend im Mastbetrieb mit Infektionsdosen, die nur zu einer milden klinischen Symptomatik führen. In den meisten Fällen überstehen die Tiere die Infektion mit Salmonella und Y. enterocolitica und werden zu klinisch inapparenten Keimträgern. Solche Schweine stellen ein Reservoir für die Infektion anderer Tiere und für den Eintrag in die Lebensmittelkette dar. Im Rahmen dieser Arbeit wurden zwei PCR-Methoden zum spezifischen Nachweis von Salmonella und Y. enterocolitica im Schlachtschwein entwickelt und anhand von Probenmaterial aus eigens dafür durchgeführten Infektionsversuchen mit S. Typhimuirum und Y. enterocolitica evaluiert. Beide Methoden mussten sich am diagnostischen Goldstandard für den jeweiligen Erreger messen lassen. Für Salmonella Typhimurium wurde die ISO-Norm 6579 und für Y. enterocolitica die ISO-Norm 10273 zum kulturellen Nachweis ausgewählt. Es konnte eine neue PCR-Methodik zum Salmonella-Nachweis in 14 verschiedenen Gewebeproben etabliert werden, die im Vergleich zum kulturellen Nachweis nach ISO 6579 eine Sensitivität von 100 % und eine Spezifität von 96 % aufweist und die Zeitspanne bis zum spezifischen Nachweis des Erregers um mindestens 24 Stunden reduziert. Die Untersuchungen erfolgten anhand von 420 Gewebeproben aus persistent infizierten Schweinen aus Infektionsversuchen mit S. Typhimurium DT104. Dieses neu entwickelte und validierte PCR-Verfahren wurde mit einem bereits etablierten PCR-Nachweissystem nach RAHN et al. (1992) - wie in der DIN 10135 angegeben - verglichen. Beide PCR-Methoden basieren auf dem invA-Virulenzgen von S. Typhimurium. Im Infektionsversuch konnten zwei Gewebeproben (Caecum und Lnn. Ileocolici) bestimmt werden, durch deren Kombination man mit beiden Nachweismethoden 96 % (23 von 24 Tieren) aller im Versuch infizierten Schweine als Salmonella positiv identifizieren konnte. Erstmals gelang in dieser Arbeit der Nachweis des yopT-Gens bei plasmidtragenden Y. pseudotuberculosis-Stämmen sowie die Bestimmung der Sequenz (European Bioinformatics Institute, Accession-Number: AJ304833). Das yopT-Gen kodiert für ein 35,5 kDa großes Effektor-Protein, das einen zytotoxischen Effekt auf HELA-Zellen und Makrophagen besitzt. Durch den Nachweis des yopT-Gens bei Y. pseudotuberculosis-Stämmen war es erstmals möglich, eine für Y. enterocolitica spezifische, auf dem yopT-Gen des Virulenzplasmids basierende PCR-Methode zu etablieren, die auch die Diskriminierung von Y. pseudotuberculosis-Isolaten gestattet. In einem weiteren Infektionsversuch konnte gezeigt werden, dass es die auf dem yopT-Gen von Y. enterocolitica basierende PCR-Methode erlaubt, Carrier-Tiere mit hoher Sensitivität (100 %) und Spezifität (87 %) innerhalb von 56 Stunden in lymphatischen Geweben zu identifizieren. Besonders geeignet für den Nachweis mit der ISO 10273 und dem neu etablierten yopT PCR-Verfahren waren das Ileum und die Lnn. ileocolici. In dieser Arbeit ist der Versuch gelungen, die Diagnostik für zwei der drei wichtigsten beim Schwein vorkommenden humanen Enteritiserreger zu standardisieren, indem Kombinationen aus Gewebeproben bestimmt wurden, die sowohl für den Nachweis mit der jeweiligen Goldstandard-Methode als auch mit den schnelleren und sensitiveren PCR-Methoden geeignet sind. Die Ergebnisse dieser Arbeit tragen zu einer deutlichen Verbesserung der Diagnostik von Salmonella und Y. enterocolitica beim Schlachtschwein bei. Es bleibt zu hoffen, dass somit der Eintrag dieser Zoonoseerreger in die Lebensmittelkette reduziert und der Verbraucherschutz auf diesem Gebiet beträchtlich verbessert werden kann. / The infection with Salmonella and Yersinia (Y.) enterocolitica through foodstuff from slaughter pigs is one of the major problems of hygienic consumer protection. To avoid the contamination of products from pig industry modern and well validated bacteriological identification systems are necessary. An infection predominantly occurs in the fattening pens, showing mild clinical symtoms only. The majority of infected pigs overcome the infection with Salmonella and Y. enterocolitica and become clinically inapparent carrier pigs. Those pigs are a reservoir for the contamination of other animals and pork products. In the context of this work two PCR-assays for the specific detection of Salmonella and Y. enterocolitica have been developed and validated on the basis of tissue samples from experimentally infected pigs. Both methods have been compared with the classical bacterial culture. Two international standards were used for bacterial detection: ISO 6579 for S. Typhimurium and ISO 10273 for pathogenic Y. enterocolitica. It was possible to establish a new PCR-assay for the specific detection of Salmonella in 14 different tissues of experimentally infected pigs. In comparison to the standard ISO 6579 a sensitivity of 100 % and a specificity of 96 % were calculated for the PCR-assay. The investigations were carried out with 420 tissue samples of persistently infected pigs that have been experimentally infected with S. Typhimurium. By using the PCR-method for the detection of Salmonella in positive tissue samples, the detection-time could be reduced around 24 hours. The new PCR-assay developed and validated in this work, was compared with the PCR-method described in DIN 10135, which is based on the studies of RAHN et al. (1992). Both methods were based on the invA-virulence gene of S. Typhimurium. A combination of samples from ileocolic lymph node and caecum was particularly suitable for the detection of 96 % of the experimentally infected pigs (23 off 24 animals) with the PCR-assay and the culture method. In this study, the yopT-gene was proved for the first time to be present in plasmid bearing Y. pseudotuberculosis-Isolates, and the nucleotid sequence was determined (European Bioinformatics Institute, Accession-Number: AJ304833). YopT encodes a 35.5 kDa effector protein (YopT), which induces a cytotoxic effect in HeLa cells and macrophages. This finding was used to develop a specific PCR-assay for the detection of pathogenic Y. enterocolicica strains and the discrimination from pathogenic Y. pseudotuberculosis strains. Embedded in an experimental Y. enterocolitica-infection-model in swine, it was shown that the yopT PCR-assay is suitable for the detection of pathogenic Y. enterocolitica in lymphatic tissue of persistently infected pigs. The yopT PCR-method shows a sensitivity of 100 % and a specificity of 87 % in lymphatic tissue. By the use of the PCR-assay, the detection of Y. enterocolitica was possible within 56 hours. A combination of specimens from the ileum and ileocolic lymph nodes was most suitable for the detection of pathogenic Y. enterocolitica in slaughter pigs with the ISO-Standard 10273 and the yopT PCR. This investigation succeeded in standardizing the identification of two of the three most important zoonotic agents for human enteric disease. The standardization was achived by the use of a combination of samples suitable for the identification with both, the “Goldstandard” and the specific and rapid PCR-method. The results of this work offer a better identification of Salmonella and Y. enterocolitica in slaughter pigs in the future. Based on these facts it is possible to avoid contamination of food products from slaughter pigs and to improve the hygienic consumer protection considerably.
455

Exploring persistent homology as a method for capturing functional connectivity differences in Parkinson’s Disease. / Utforskning av ihållande homologi som en metod för att fånga skillnader i funktionell konnektivitet hos Parkinsons sjukdom.

Hulst, Naomi January 2022 (has links)
Parkinson’s Disease (PD) is the fastest growing neurodegenerative disease, currently affecting two to three percent of the population over 65. Studying functional connectivity (FC) in PD patients may provide new insights into how the disease alters brain organization in different subjects. We explored persistent homology (PH) as a method for studying FC based on the functional magnetic resonance imaging (fMRI) recordings of 63 subjects, of which 56 were diagnosed with PD.  We used PH to translate each set of fMRI recordings into a stable rank. Stable ranks are homological invariants that are amenable for statistical analysis. The pipeline has multiple parameters, and we explored the effect of these parameters on the shape of the stable ranks. Moreover, we fitted functions to reduce the stable ranks to points in two or three dimensions. We clustered the stable ranks based on the fitted parameter values and based on the integral distance between them. For some of the parameter combinations, not all clusters were located in the space covered by controls. These clusters correspond to patients with a topologically distinct connectivity structure, which may be clinically relevant. However, we found no relation between the clusters and the medication status or cognitive ability of the patients. It should be noted that this study was an exploration of applying persistent homology to PD data, and that statistical testing was not performed. Consequently, the presented results should be considered with care. Furthermore, we did not explore the full parameter space, as time was limited and the data set was small. In a follow-up study, a measurable desired outcome of the pipeline should be defined and the data set should be expanded to allow for optimizing over the full parameter space. / Parkinsons sjukdom är den snabbast växande neurodegenerativa sjukdomen och drabbar för närvarande två till tre procent av befolkningen över 65 år. Att studera funktionell konnektivitet (FC) hos patienter med Parkinson kan ge nya insikter om hur sjukdomen förändrar hjärnans uppsättning i olika områden. Vi använde oss av persistent homologi (PH) som en metod för att studera FC baserat på inspelningar av funktionell magnetresonanstomografi (fMRI) av 63 försökspersoner varav 56 hade diagnosen PD. Vi använde oss av persistent homologi (PH) som en metod för att studera FC baserat på inspelningar av funktionell magnetresonanstomografi (fMRI) av 63 försökspersoner varav 56 hade diagnosen PD. Vi använde PH för att översätta varje uppsättning fMRI-prov vardera till en stable rank. Stable ranks är homologiska invarianter som är lämpliga för statistisk analys. Pipelinen har flera parametrar och vi undersökte effekten av dessa parametrar på formen av dessa stable ranks. Vi anpassade funktioner för att reducera alla stable ranks till punkter i två eller tre dimensioner. Vi grupperade alla stable ranks utifrån de anpassade parametervärdena och utifrån det integrala avståndet mellan dem. För vissa parameterkombinationer kunde inte alla kluster inom det område som täcks av kontrollerna bli funna. Dessa kluster motsvarar patienter med en topologiskt distinkt konnektivitetsstruktur, vilket kan vara kliniskt relevant. Vi fann dock inget samband mellan klustren och patienternas läkemedelsstatus eller kognitiva förmåga.  Det bör noteras att den här studien var en undersökning på tillämpningen av persistent homologi på PD-data och att statistiska tester inte utfördes. Följaktligen bör de presenterade resultaten betraktas med försiktighet. Dessutom undersökte vi inte hela parameterutrymmet eftersom tiden var begränsad och datamängden liten. I en uppföljningsstudie bör man definiera ett mätbart önskat resultat av pipelinen och datamängden bör utökas för att möjliggöra optimering av hela parameterutrymmet.
456

A sea of contested evidence: Disputes over coastal pollution in Hout Bay, Cape Town, South Africa

Beukes, Amy 23 June 2022 (has links)
The City of Cape Town's (CoCT) wastewater management system discharges effluent from households, industries and other sources into the Atlantic Ocean through deep-water marine outfalls in Green Point, Camps Bay and Hout Bay. At total capacity, these three outfalls discharge 55.3 megalitres (Ml) into marine receiving environments daily. With minimal pre-treatment that amounts to screening and sieving, this results in microbial and chemical pollution of the sea (including chemicals of emerging concern), marine organisms, recreational beaches, and Marine Protected Areas (MPAs). This research focuses on contestations over evidence of that pollution in Hout Bay. The study documents the work of independent scientists seeking to provide evidence of coastal pollution obtained via microbial and chemical analyses of water (coastal and inland) and marine organisms (Mytilus galloprovincialis) samples. It also presents accounts of pollution obtained via ethnographic research with local residents, fishers, frequent water users and river activists who have observed and experienced poor coastal water quality. However, the form of evidence that is considered and informs decision-making processes by the CoCT has consistently sought to invalidate these forms of evidence, from both independent scientists and the public. Debates around knowledge of water and contests over evidence that highlight the entanglements of science, politics, and ways of knowing make visible a consistent pattern in coastal water-quality governance by the City, which results in inaction regarding the ever-growing issue of coastal pollution in Cape Town.
457

Decomposition and Stability of Multiparameter Persistence Modules

Cheng Xin (16750956) 04 August 2023 (has links)
<p>The only datasets used in my thesis work are from TUDatasets, <a href="https://chrsmrrs.github.io/datasets/">TUDataset | TUD Benchmark datasets (chrsmrrs.github.io)</a>, a collection of public benchmark datasets for graph classification and regression.</p><p><br></p>
458

Per- and Polyfluoroalkyl Substance (PFAS) Emissions from Recycling Processes of Lithium-Ion Batteries

Rensmo, Amanda January 2022 (has links)
The lithium-ion battery (LIB) recycling industry is currently under development to improve the yields for critical metals. However, the organic components of LIBs must also be handled, which may result in harmful chemical emissions as by-products. Of particular concern are highly persistent and mobile per- and polyfluoroalkyl substances (PFAS) that could be released during LIB recycling since some of these compounds have been linked with adverse health effects. In this work, an extensive literature review was conducted to determine the presence of fluorinated materials in state-of-the-art LIBs and the recycling conditions which could lead to the release of problematic PFAS. This information was used to develop a new analytical approach to capture the broadest range of organic and inorganic fluorine species in samples taken in different stages of the recycling process. This new method is based on a sequential extraction procedure using different solvents, followed by combustion ion chromatography (CIC) to quantify the potential emission of fluorine-containing chemicals of different polarities. The results show that organofluorine compounds are formed during recycling, particularly for the cathodes, indicating that PFAS might be present. For other samples, such as the NiMnCo salt product of recycling, only low fluorine levels were detected which implies almost complete removal. Future work should further outline the emission paths of these processes. This study highlights the necessity to further investigate the emissions related to fluorinated materials during LIB recycling and indicates that post-treatments or changes in conditions might be necessary to avoid the formation and emission of PFAS.
459

Immunhistokemisk (IHC) analys av låggradigt inflammerade biopsier med apikal parodontit -en pilotstudie / Immunohistochemical (IHC) analysis of biopsies with apical periodontitis with assessed low-grade inflammation – a pilot study

Pesonen, Izabell, Ismail, Midia January 2021 (has links)
Syfte: Att ta reda på hur relationen ser ut för B- respektive T-lymfocyter i biopsier av rotfyllda tänder med apikal parodontit med bedömd låggradig inflammation. Denna studie kommer även att analysera hur den inflammatoriska bilden ser ut i förhållande till beskrivna symtom i dessa biopsier. Material &amp; metod: En pilotstudie utfördes på 10 biopsier från rotfyllda tänder med apikal parodontit med bedömd låggradig inflammation enligt Danesh et al 2019 klassificeringssystem. Biopsierna hämtades från Malmö universitets biobank. Immunhistokemisk infärgning av antigenerna CD20+ och CD3+ utfördes samt analyserades med hjälp av digitalmikroskop. Jämförelsen av symtomen från remisserna skedde efter att de histologiska resultaten sammanställts. Resultat: Det fanns fler T-lymfocyter än B-lymfocyter i 6 stycken av biopsierna. I de resterande 4 biopsierna var de lika många. I remisserna hade symtombilden inte angetts föralla biopsier. Slutsats: Enligt vår pilotstudie ser vi tendenser till att T-lymfocyter är fler än B-lymfocyter eller att de är lika många. Inga slutsatser kunde dras gällande symtombilden. Ett större material från olika remittenter krävs för definitiva slutsatser. En vidare infärgning av CD4+ samt CD8+ skulle vara intressant. / Aim: To investigate the relation between B- and T- lymphocytes in biopsies of root-filled teeth with apical periodontitis with assessed low-grade inflammation. This study will also analyse what the inflammation looks like in relation to the symptoms described in these biopsies.  Study design: A pilot study was performed on 10 biopsies of root-filled teeth with apical periodontitis with assessed low-grade inflammation according to the classification system of Danesh et al 2019. The biopsies were collected from Malmö University's biobank. An immunohistochemical staining of antigens CD20+ and CD3+ were performed and analysed by a digital microscope. A comparison of the symptoms from the referrals were performed once the histological results were compiled. Results: There were more T-lymphocytes than B-lymphocytes in 6 of the biopsies. In the remaining 4 biopsies there were an equal amount of B- and T-lymphocytes. The symptoms were not stated for all biopsies in the referrals.  Conclusion: According to our pilot study, we see tendencies that T lymphocytes are more than B lymphocytes or that they are equal. No conclusions could be drawn regarding the symptom picture. Larger material from different referrers is required for definitive conclusions. A further staining of CD4 + and CD8 + would be interesting.
460

Subthreshold Oscillations and Persistent Activity Modulate Spike Output in the Rodent Dentate Gyrus

Anderson, Ross William 09 February 2015 (has links)
No description available.

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