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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.
131

Rhinite : caractérisation et association avec la pollution atmosphérique / Rhinitis : characterization and association with air pollution

Burte, Marthe-Emilie 02 March 2018 (has links)
Alors que la rhinite a un fort impact sur la santé publique, chez l’adulte, il n’existe pas de définition standardisée de la rhinite dans les études épidémiologiques. De plus, les facteurs environnementaux de la rhinite sont mal connus et, en particulier, il existe très peu d'études sur les effets à long terme de la pollution atmosphérique sur la rhinite chez l'adulte. Pour combler ces lacunes, nous avons utilisé les données de deux études épidémiologiques multicentriques européennes ayant des données détaillées sur la santé respiratoire et d'exposition annuelle individuelle à la pollution atmosphérique. Nos résultats ont montré que pour mieux caractériser la rhinite, il faut considérer l’ensemble des caractéristiques des symptômes nasaux, les comorbidités et la sensibilisation allergique, et ne pas limiter la maladie à une question ou à un test de sensibilisation allergique. Nous n'avons trouvé aucune association entre la pollution atmosphérique à long terme et l'incidence de la rhinite, mais nous avons montré que l'exposition à long terme à la pollution était associée à une augmentation de la sévérité de la rhinite, soulignant le besoin de contrôler les niveaux de pollution atmosphérique. / Whereas rhinitis has an important public health impact, in adults there is no standardized definition of rhinitis in epidemiological studies. Furthermore, environmental factors of rhinitis are barely known, and in particular, there are very few studies on the effects of long-term exposure to air pollution on rhinitis in adults. To fill these gaps, we used data from two European multicentre epidemiological studies with extensive data on respiratory health and individual estimated exposures to long-term air pollution. Our findings showed that to better characterize rhinitis, one need to consider together all the characteristics of the nasal symptoms, the comorbidities and the allergic sensitization, and not to restrict the disease to one question or one allergic sensitization test. We found no association between long-term air pollution and incidence of rhinitis, but we showed that long-term exposure to air pollution is associated to an increased severity of rhinitis, emphasising that air pollution needs to be controlled.
132

Effects of Developmental Low-Level Lead Exposure on Voluntary Alcohol Consumption and Drug-Induced Behavioral Sensitization in Adulthood

Hernández, Maribel 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Lead (Pb) is one of the most harmful and most abundant neurotoxins in the environment. Despite the extensive movement made to eradicate toxic levels of Pb in the environment, children, predominately in lower socioeconomic areas, are still exposed to varying levels of Pb. Human studies suggest that Pb exposure leads to altered drug consumption in adults by altering underlying neural mechanisms, specifically dopamine (DA) activity. However, there is limited research on this at blood Pb levels below 10 μg/dL, levels often seen in children growing up in neighborhoods located in old industrial and urban areas. To model how early-life low-level Pb exposure effects DA-dependent behaviors associated with addiction in adulthood, we used C57BL/6J mice. Litters were weaned at PND 21 and assigned to either a three-week history of 30 parts per million (ppm) Lead (IV) Acetate exposure or a control condition of 0 ppm Pb in DI drinking water. After the Pb exposure period, mice were switched to regular tap water until they reached adulthood. Afterward, separate animals were tested in one of three experiments: two-bottle choice alcohol preference drinking, alcohol-induced behavioral sensitization (EBS), and cocaine-induced behavioral sensitization (CBS). In experiment 1, our hypothesis was met, and both male and female mice with a prior Pb exposure displayed significantly higher alcohol intake and preference scores over the three-week period than control mice. In experiment 2, there were no differences in EBS and no evidence of EBS in any of the groups. However, there was an increased acute response to 2.0 g/kg EtOH in the Pb-exposed chronic group as compared to the control animals. Lastly, in experiment 3, Pb-exposed animals in the chronic cocaine group were more sensitive to the effects of cocaine (10 mg/kg) across days than the controls, both the acute cocaine groups and both saline control groups. Thus, with these experiments, we concluded that low levels of developmental Pb exposure might be targeting DA in the reward pathway, which is essential for alcohol intake and drug sensitization.
133

Mechanisms Regulating Transient Receptor Potential Cation Channel A1 (TRPA1) and Their Roles in Nociception and Nociceptive Sensitization

Shang, Ye 26 June 2020 (has links)
Nociception is the sensory nervous system that detects harmful stimuli including excessive heat, cold, toxic chemicals, and noxious mechanical stimulations. Transient receptor potential (TRP) channels are a group of evolutionarily conserved ion channels consisting of 4 subunits, each with 6 transmembrane spans, and detect a variety of external and internal nociceptive stimuli. Due to their critical roles in nociception, it is essential to understand the mechanisms that regulate TRP channels and subsequent nociception. Here, I investigated two distinct types of regulation of Drosophila transient receptor potential cation channel A1 (TrpA1): regulation via the expression of different TrpA1 isoforms, and via its binding with associated proteins. I found that one of the TrpA1 isoforms, TrpA1(E), inhibits the thermal responses of other TrpA1 isoforms in vitro. I also identified potential TrpA1 binding partners through Co- immunoprecipitation (Co-IP) and mass spectrometry analysis. These binding partners need further validation and characterization through biochemical, cellular, and behavioral assays to illustrate their roles in nociception, and may serve as potential drug targets for chronic pain.
134

Near-IR Dye Sensitization of Polymer Solar Cells / 高分子太陽電池の近赤外色素増感

Xu, Huajun 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18291号 / 工博第3883号 / 新制||工||1596(附属図書館) / 31149 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 伊藤 紳三郎, 教授 木村 俊作, 教授 辻井 敬亘 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
135

Nicotine Sensitization in β-Arrestin 2 Knockout Adolescent Mice.

Correll, Jennifer A 14 August 2007 (has links) (PDF)
ß arrestin-2 is a protein involved in signaling of D2 receptors and plays a mediating role in sensitization to psychostimulants and the opiate morphine. In this study, 3-4 week old BA-2 KO and wild type C57/B6 mice received nicotine tartarate (s.c, 0.5 mg/kg free base) for 7 or 14 consecutive days followed by a drug-free period. An acute nicotine challenge followed the drugfree period. Results indicated that the absence of ß-arrestin-2 reduced sensitization to nicotine in Experiment 1. BA-2 KOs eventually demonstrated sensitization in Experiment 2. However, absence of ß-arrestin-2 blocked expression of sensitization on the challenge. After the challenge, brain tissue was removed and the nucleus accumbens was dissected and analyzed for brainderived neurotrophic factor (BDNF). Results showed that BDNF positively correlated with behavioral results. These results appear to indicate the importance of the ß-arrestin-2 protein in locomotor sensitization and that dopamine signaling is related to BDNF.
136

Dye sensitzation effects on lanthanide upconversion nanoparticles

Bäck, Dag Albin, Jörgensen, Andreas January 2022 (has links)
In this report we studied the properties of the dye IR806 and possible mechanisms of the dye sensitization effect on ytterbium-erbium co-doped upconversion nanoparticles. We found that the dye IR806 has two primary emission peaks in the NIR spectral range at around 850 nm and at around 950 nm. The intensity of these peaks were observed to be affected by the concentration of the dye and the addition of Gadolinium(III) chloride and Yttrium(III) chloride. Specifically increases in the intensity of the 950 nm peak relative to the 850 nm were of interest since ytterbium readily absorbs 950 nm and transfers this energy in the upconversion process. Our hypothesis is that the change in the intensity of the 850 nm and the 950 nm peak is associated with aggregation of the dye IR806 and the amount of monomers and dimers. Results from adding ytterbium-erbium co-doped upconversion nanoparticles in IR806-ethanol solution points to the picture of dimers being formed on the surface on the nanoparticles. This analysis is however based on the assumption that the 850 nm emission peak of IR806 is associated with monomers and that the 950 peak is associated with dimers, which is yet to be confirmed and further studies are therefore needed.
137

Does Predation Environment Affect Repeated Responses to Predation Cues in the Fish Brachyrhaphis rhabdophora?

Nate, Madeleine S. 12 December 2022 (has links) (PDF)
Individual organisms face trade-offs when dealing with predation—more time spent avoiding predators often results in less time allocated to energy acquisition and reproductive-related activities. Individuals that optimize this trade-off and respond appropriately to current risk levels in their environment should be at an advantage. What is less clear is whether this tradeoff changes when individuals are repeatedly exposed to a predation threat. There may be advantages to responding consistently to every signal of threat, but it might also be advantageous to modulate individual behavior. Moreover, it is unclear how evolutionary history of a population might affect such individual responses. Our study was designed to address two questions: (1) how do B. rhabdophora respond to repeated exposures of a predation cue; and (2) do repeated responses differ based on evolutionary history? To answer these questions, we used a predation cue stimulus to repeatedly expose B. rhabdophora individuals from both high- and low-predation populations. We measured the change in total distance traveled in a 15-minute trial before and after each cue exposure, and then compared the proportional change in response to the first cue to that of each successive cue (repeated four times) to see if a decrease in response occurred. We found that fish responded consistently to each cue exposure. Both populations showed similar decreases in activity in response to each exposure and did not return to normal baseline activity until the cue was removed from the test tank. That both high- and low-predation populations respond consistently to repeated cues of predation with no reinforcement prompts questions as to the potential importance of the relative length of risk and safe periods in affecting response variation. It also provides a starting point in understanding how recent risk exposure and the evolutionary history of risk in a population both interact to influence individual response to threats over time.
138

Potential Co-Factors of an Intraoral Contact Allergy—A Cross-Sectional Study

Olms, Constanze, Schor, Jana, Yahiaoui-Doktor, Maryam 13 April 2023 (has links)
The aim of this cross-sectional study was to evaluate the frequency of dental allergens and potential co-factors, especially hypothyroidism, for patients with an intraoral contact allergy. From 2015 to 2016, patients with confirmed symptoms of an intraoral contact allergy (study group SG n = 50) were recruited in the dental clinic of the University of Leipzig. The participants of the control group (CG n = 103) were patients without oral diseases or intraoral symptoms of a contact allergy. For the data collection, a new “Allergy questionnaire” was developed. Information on allergies and general diseases were collected. The statistical analysis was carried out with SPSS 23.0. Sensitizations/allergies to metals and composites were higher in SG compared to CG. Of all study participants (n = 148), 14.2% (n = 21) had a nickel allergy. In 18% (n = 8) of the SG a cobalt allergy based on all metal allergens could be seen. In addition, an association between a nickel and cobalt allergy was found. Hypothyroidism occurred significantly more frequently (p = 0.049) in SG than in CG. Sensitizations and allergies can occur to metals in dental alloys. Hypothyroidism increased the risk of having an allergy threefold.
139

Focused Ultrasound-Induced Cavitation Sensitizes Cancer Cells to Radiation Therapy and Hyperthermia

Hu, Shaonan, Zhang, Xinrui, Unger, Michael, Patties, Ina, Melzer, Andreas, Landgraf, Lisa 17 April 2023 (has links)
Focused ultrasound (FUS) has become an important non-invasive therapy for solid tumor ablation via thermal effects. The cavitation effect induced by FUS is thereby avoided but applied for lithotripsy, support drug delivery and the induction of blood vessel destruction for cancer therapy. In this study, head and neck cancer (FaDu), glioblastoma (T98G), and prostate cancer (PC-3) cells were exposed to FUS by using an in vitro FUS system followed by single-dose X-ray radiation therapy (RT) or water bath hyperthermia (HT). Sensitization effects of short FUS shots with cavitation (FUS-Cav) or without cavitation (FUS) to RT or HT (45 °C, 30 min) were evaluated. FUS-Cav significantly increases the sensitivity of cancer cells to RT and HT by reducing long-term clonogenic survival, short-term cell metabolic activity, cell invasion, and induction of sonoporation. Our results demonstrated that short FUS treatment with cavitation has good potential to sensitize cancer cells to RT and HT non-invasively.
140

Cellular Antagonization of the Type 1 Interferon Response for the Potentiation of Oncolytic Virotherapy

Wong, Boaz 25 January 2024 (has links)
Oncolytic viruses (OVs) have made tremendous strides as a viable cancer therapeutic in recent years; however, variable infectivity rates have since limited clinical efficacy. Residual type 1 interferon (IFN-1) responses are integral to the tumour’s innate antiviral defense and confer resistance to OVs. To combat this, small molecules with viral sensitizing ability can be used in combination to transiently knockdown IFN-1 responses, allowing OVs to gain a foothold for increased infectivity and therapeutic efficacy. Accordingly, we hypothesize that some chemical or genetic manipulations of cellular processes can indirectly antagonize antiviral IFN-1 responses and modulate pro-inflammatory pathways to potentiate oncolytic virotherapy. In this thesis, we identify several avenues to modify cell signalling events to increase OV therapeutic efficacy through IFN-1 inhibition. Firstly, with respect to the demonstrated OV-enhancing effects of vanadium, a pan-phosphatase (PP) inhibitor, we elucidate that its IFN-1 suppressing activity involves activation of the epidermal growth factor receptor (EGFR) pathway via STAT1/2 and NF-κB. Pharmacological inhibition of EGFR abrogated vanadium’s viral sensitizing ability in vivo. Secondly, using high-throughput screening methodology, we identify protein phosphatases that inherently regulate the IFN-1 response as targets for oncolytic vesicular stomatitis virus (VSV∆51) potentiation. Indeed, cloning interfering RNA against one of these PP targets, acid phosphatase 2 (ACP2), into the VSV∆51 platform demonstrated superior infectivity and cancer cell cytotoxicity compared to the non-targeting VSV∆51 control. Thirdly, we characterize pevonedistat, a first in-class neddylation activating enzyme inhibitor, to potentiate OV therapeutic efficacy across several in vitro and in vivo contexts. We demonstrate pevonedistat’s ability to inhibit IFN-1 signalling and pro-inflammatory cytokine production using both neddylation independent and dependent mechanisms. Taken altogether, we dissect multiple signaling mechanisms by which the IFN-1 response can be modulated for the purposes of improving OV therapeutic efficacy. This knowledge can subsequently be directly translated into designing optimized OV strategies for clinical testing.

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