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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.
21

Quantitave Evaluation of Biometeorological Conditions in Lithuania / Biometeorologinių sąlygų Lietuvoje kiekybinis vertinimas

Liukaitytė, Judita 30 March 2011 (has links)
Biometeorological information provides early warnings about health risks and possible effects of complex meteorological conditions on human health or comfortability. The aim of the present research is to determine the weather impact on human health in Lithuania and accomplish evaluation of biometeorological conditions in the country. In the research a sociological evaluation of weather sensitivity of Lithuanian population was carried out. There also was measured the impact of the weather conditions on cardiovascular disease recurrent in Vilnius and the most meteo sensitive diseases were identified as well as their dependence on the current weather conditions. The change of indices describing biometeorological cold (Wind Chill) and heat („Humidex“) effects was analysed. The impact of heat on mortality of Vilnius residents was evaluated and appropriate indicators were determined to provide heat warnings in Lithuania. There was performed a calibration of ultraviolet radiation values measured in Kaunas MS and assessed the appropriateness of STAR model for forecasting of UV radiation intensity in Lithuania. The results of dissertation can be used to make biometeorological forecasts. On the basis of this work, the system of existing early warnings about elemental, catastroffic and other hazardous weather events could be improved. / Biometeorologinė informacija suteikia išankstinius perspėjimus apie sveikatai gresiantį pavojų, kaip meteorologinių sąlygų kompleksas veiks žmonių sveikatos būklę ar komfortiškumą. Šio darbo tikslas - nustatyti orų poveikį Lietuvos gyventojų sveikatai ir atlikti biometeorologinių sąlygų šalies teritorijoje vertinimą. Darbe atliktas Lietuvos gyventojų jautrumo orams sociologinis vertinimas. Nustatytas orų sąlygų poveikis širdies-kraujagyslių ligų kartojimuisi Vilniuje ir išskirtos meteojautriausios ligos ir jų priklausomybė nuo esamų meteorologinių sąlygų. Analizuota biometeorologinį šalčio poveikį nusakančio Vėjo žvarbumo ir karščio poveikį – „Humidex“ indekso kaita Lietuvoje. Įvertintas karščio poveikis Vilniaus gyventojų mirtingumui ir nustatyti indikatoriai tinkantys teikti karščio perspėjimus Lietuvoje. Atlikta Kauno MS išmatuotų ultravioletinės spinduliuotės dydžių kalibraciją bei įvertintas modelio STAR tinkamumas ultravioletinės spinduliuotės intensyvumo Lietuvoje prognozei. Disertacinio darbo rezultatai gali būti naudojami biometeorologinėms prognozėms sudaryti. Remiantis šiuo darbu, galima tobulinti egzistuojančią išankstinių perspėjimų apie stichinius, katastrofinius ir kitus pavojingus hidrometeorologinius reiškinius sistemą.
22

Synthèse et caractérisation de nanoparticules à base d'oxydes de cérium et de fer pour la filtration des UV dans les produits solaires / Synthesis and characterisation of cerium dioxide- and iron oxidebased nanoparticles for UV filtration in sunscreens

Truffault, Laurianne 08 December 2010 (has links)
L’objet de cette thèse est la synthèse et la caractérisation de nouveaux filtres UV inorganiques nanostructurés, efficaces dans le domaine des UVA. Dans ce contexte, nous avons choisi d’étudier le dioxyde de cérium (CeO2) et l’hématite (α-Fe2O3) en raison notamment de leurs propriétés optiques d’absorption des UV. Deux méthodes de synthèse ont été sélectionnées pour l’élaboration de ces oxydes, purs ou dopés, sous la forme de poudre nanométrique: la co-précipitation et le spray-pyrolyse. Les conditions optimales de synthèse ont été déterminées grâce à de la diffraction des rayons X et de l’analyse thermique. La structure cristalline ainsi que la granulométrie des échantillons obtenus ont été caractérisées par diffraction des rayons X et microscopies électroniques. La granulométrie et la morphologie des échantillons sont reliées aux méthodes de synthèse, aux conditions opératoires (atmosphère et température de calcination), à la nature et à la concentration des éléments dopants. Les propriétés optiques des échantillons suspendus dans de l’éthanol ont été étudiées par spectroscopie d’absorption UV-visible. Elles sont reliées à la granulométrie des échantillons ainsi qu’à des phénomènes localisés au sein de la maille cristallographique (changements de valence, présence de défauts). Les échantillons à base de CeO2 et α-Fe2O3 ont finalement été incorporés en émulsion solaire, à la place de ZnO, afin de tester leurs performances anti-solaires (SPF et FP-UVA) par mesure in vitro. Les résultats montrent que le ZnO peut être positivement remplacé dans les produits de protection solaire par l’oxyde de cérium ou de fer qu’ils soient purs ou dopés. / The subject of this thesis is the synthesis and the characterization of new UVA-efficient nanostructured inorganic UV filters. In this context, we chose to study cerium dioxide (CeO2) and hematite (α-Fe2O3), most importantly because of their optical absorption properties. Two methods were selected to synthesise cerium dioxide and hematite in nanostructured powder form: the co-precipitation method and the spray-pyrolysis method. Cerium dioxide was studied in both non-doped and doped forms. Optimal synthesis conditions were determined by X-ray diffraction and thermal analysis. The crystalline structure and granulometry of the obtained samples were characterised by X-ray diffraction and electronic microscopy techniques. Granulometry and morphology of the samples are linked to: the synthesis method, the experimental conditions (atmosphere and temperature of calcinations), and the nature and concentrations of the dopes. The optical properties of ethanol suspended samples were studied by UV-visible absorption spectroscopy. They are linked to the samples’granulometry as well as localised phenomena in the crystallographic lattice (valence changes, defects presence). Cerium dioxide- and hematite-based samples were finally incorporated in emulsion, instead of ZnO, in order to test their photoprotection performance (SPF and PF-UVA) by measuring in vitro. Results show that ZnO can be positively replaced by pure or doped cerium or iron oxide in sunscreen, when these are associated with the inorganic filter TiO2.
23

Método simples e rápido para seleção de fungos filamentosos produtores de compostos absorvedores de radiação UV para aplicação em protetores solares / Simple and fast method for selection of filamentous fungi producers of UV absorbing compounds for use in sunscreens

Michelle de Andrade 07 April 2016 (has links)
Foram estudadas trinta e uma cepas fúngicas não identificadas, as quais foram denominadasX1 a X31. O potencial fotoprotetor foi avaliado pela medida espectrofotométrica da absorçãodos extratos na região do UV (280-400 nm). Os extratos com os melhores perfis de absorção em cultura estacionária foram X1, X2, X6, X12, X13, X18, X19, X22, X24 e X31 e, em cultura agitada X4 e X17. A reprodutibilidade do processo foi avaliada e as cepas fúngicas que apresentaram coeficiente de variação menor que 15% foram selecionadas para o estudo de fotoestabilidade. A fotoestabilidade dos extratos foi avaliada pela medida da viabilidade celular de fibroblastos L929 tratados com extratos previamente irradiados sob radiação UVA (11,2 J/cm2) e UVB (3,43 J/cm2) e extratos não irradiados, bem como, pela comparação das áreas sob as curvas de absorção na região do UV dos extratos irradiados e não irradiados. Os extratos selecionados para o estudo de fotoestabilidade foram X4, X12, X19, X22, X24 e X31. Os extratos não irradiados apresentaram os seguintes valores deIC50 para viabilidade celular (citotoxidade): X4-130µg/ml, X19-20µg/ml, X22-10 µg/ml e X24-60µg/ml. Após a radiação UVA e UVB, os extratos apresentaram redução significativa da viabilidade celular em relação ao IC50 dos extratos não irradiados. Sob luz UVB, os extratos X12 (IC50 35µg/ml) e X31 (IC50 70µg/ml) mantiveram a mesma porcentagem de redução da viabilidade celular quando comparado ao IC50 dos extratos não irradiados. No entanto após exposição à luz UVA, o extrato X12 aumentou a viabilidade celular de 50% (quando não irradiado) para 75% (irradiado). Enquanto que o extrato X31, mesmo após a radiação UVA, manteve a mesma redução de 50% da viabilidade celular. Nessa etapa os extratos selecionados foram os X12 e X31. O espectro de absorção na região do UV obtido para o extrato X12 mostrou uma redução da absorbância de 28,3% sob radiação UVB e de 60% sob radiação UVA em relação ao extrato não irradiado. O extrato X31 apresentou uma redução da absorbância de 17,6% e30% sob radiação UVB e UVA respectivamente, em relação ao extrato não irradiado. Os fungos selecionados foram identificados por PCR, sugerindo que o fungo X12 seja o Aspergillus terreus e o X31 seja o Talaromyces pinophilus. Por fim, foi feita a identificação da substância ativa do extrato X12 empregando a técnica de desreplicação, a qual fez o uso da instrumentação analítica acoplada UHPLC-DAD-(ESI)-HRMS associada ao banco de dados Chapman& Hall\'s Dictionary of Natural Products (DNP). No extrato X12 o composto majoritário foi identificado como sendo a citreoviridina. Assim, os resultados do presente trabalho permitiu estabelecer um procedimento para a seleção de fungos produtores de compostos absorvedores de radiação UV, que poderia ser aplicado na obtenção de novos filtros orgânicos naturais para protetores solares. / It were studied thirty-one fungal strains not identified, which were named X1 to X31. The photoprotective potential was assessed spectrophotometrically by measuring absorption of the extract in the UV region (280-400 nm). The extracts that presented the best absorption profiles in stationary culture were X1, X2, X6, X12, X13, X18, X19, X22, X24 and X31, and X4 and X17 in stirred culture. The reproducibility of the process was evaluated and fungal strains that showed a coefficient of variation lower than 15% were selected for the study of photostability. The photostability of the extracts was assessed by measuring cell viability of L929 fibroblasts treated with extracts previously irradiated under UVA light (11,2 J/cm2) and UVB (3,43 J/cm2) and not irradiated extracts, as well as by comparison of the areas under the curves of absorption in the UV region of the irradiated and non-irradiated extracts. The extracts selected for the study of photostability were X4, X12, X19, X22, X24 and X31. The non-irradiated extracts showed the following IC50 values for cell viability (cytotoxicity): X4- 130?g/ml X19-20?g/ml, X22-10/ml and X24-60?g/ml. After UVA and UVB radiation, the extracts showed significant reduction in cell viability compared to the IC50 of the unirradiated extracts. Under UVB light, the X12 extracts (IC50 35?g/ml) and X31 (IC50 70mg/ml) maintained the same percentage of cell viability reduction when compared to the IC50 of the unirradiated extracts. However after exposure to UVA light, X12 extract increased the cell viability from 50% (when not irradiated) to 75% (irradiated). While X31 extract even after the UVA irradiation, remained the same 50% of reduction in cell viability. At this stage the selected extracts were X12 and X31. The absorption spectrum in the UV region obtained for X12 extract showed a decrease in absorbance of 28.3% under UVB and 60% under UVA radiation relative to non-irradiated extract. The X31extract showed a reduction in absorbance of 17.6% and 30% in UVA and UVB radiation, respectively, compared to non-irradiated extract. The selected fungi were identified by PCR, suggesting that X12 fungus is Aspergillus terreus and X31 is the Talaromyces pinophilus. Finally it was identified the active substance of X12 extract employing dereplication technique which makes use of coupled analytical instrumentation UHPLC-DAD- (ESI) HRMS associated to the Chapman and Hall\'s Dictionary of Natural Products (DNP) database. The majority compound of X12 extract was identified as the citreoviridin. Thus, the results of this study allowed us to establish a procedure for the selection of producers of UV absorbing compounds from fungi, which could be applied in obtaining new natural organic filters for sunscreens.
24

Stimuler les défenses des plantes contre botrytis cinerea par des rayonnements UV-C / Stimulating plant defences against botrytis cinerea by UV-C radiation

Vasquez, Hilarion 22 November 2017 (has links)
Il y a désormais un consensus autour de l’idée que nous devons réduire l’usage des pesticides (Plan Ecophyto). Il est donc nécessaire de développer des systèmes de cultures réduisants l’utilisation des pesticides au profit d’un système de production dans lequel on stimule les mécanismes de défense «naturels» des plantes. Dans ce contexte, on voit aujourd’hui se développer de nombreuses solutions d’origines chimique ou biologique à base de stimulateurs de défenses des plantes (SDP) mais dont l’efficacité est souvent jugée aléatoire. Dans ce travail, notre choix a porté sur l’utilisation des rayonnements UV-C pour stimuler les défenses de la laitue et de la tomate contre Botrytis cinerea. L’idée d’exploiter les rayonnements UV-C, comme stimulateurs des défenses des plantes à intérêt alimentaire en culture, n’a jamais été testée. Nos résultats démontrent clairement un effet stimulateur des défenses des plantes par des doses faibles et répétées d’UV-C (inférieur à 1,70 kJ/m2). Cette stimulation est associée au renforcement de la paroi cellulaire, à l’augmentation des composés phénoliques et à l’augmentation de l’activité de certaines enzymes antioxydantes. Lorsque le traitement par les rayonnements UV-C est combiné à l’agent biologique Bacillus subtilis aucun effet synergique ou même additif n’a été observé par rapport à un traitement simple UV-C ou B. subtillis. / There is now a consensus around the idea that we must reduce theuse of pesticides (Plan Ecophyto). It is therefore necessary to develop cropsystems that have less need to be protected by pesticides in favor of aproduction system in which the "natural" defense mechanisms arestimulated. In this context, many solutions of chemical or biological originbased on stimulation of plant defense are now being developed but theireffectiveness is often judged to be random. In this work, we chose to useUV-C radiation to stimulate the defenses of lettuce and tomato againstBotrytis cinerea. The idea of exploiting radiation UV-C, as a stimulant ofplant food-borne defenses in culture, has never been tested. Our resultsclearly demonstrate a stimulatory effect of plant defenses by low andrepeated doses of UV-C (less than 1.70 kJ/m2). This stimulation isassociated with a reinforcement of the cell wall, an increase in the phenoliccompounds and the activity of certain antioxidant enzymes. When treatmentwith UV-C radiation is combined with a biological agent Bacillus subtilis, nosynergistic or even additive effect has been observed compared with asimple UV-C or B. subtillis treatment. / Se ha establecido en el mundo entero la importancia sobre el controlde uno de los principales organismos fitopatológicos como lo es Botrytiscinérea, el cual demanda en la actualidad a los productores aplicarcontroles cónsonos con la protección del medio ambiente. Por consiguiente,se evaluó el uso de diferentes dosis de luz ultravioleta sola o encombinación con un agente de biocontrol (Basillus subtilis), con la finalidadde estimular las defensas naturales de dos especies vegetales (lechuga ytomate). Al respecto, los resultados establecieron que dosis menores de1,70 kJ/m2 de UV-C logran disminuir la sensibilidad de las plantas, sinafectar significativamente el desenvolvimiento del aparato fotosintético deambas especies. Así como, se observó un efecto antagónico del biocontrolsobre la UV-C cuando se combinan.
25

Podnikatelský záměr / Business Plan

Pávek, Stanislav January 2012 (has links)
The objective of this thesis is to prepare a business plan on establish a new company focused on technology low-volume printing self adhesive labels and other flexible materials with methods of UV flexo and digital printing. The author's method of digital printing holds a protected utility design (Úřad průmyslového vlastnictví, registration number 11001, dated March 19, 2001)
26

Radiative transfer in the interstellar medium : some applications of the Monte Carlo technique

Srivastava, Sudha January 1999 (has links)
No description available.
27

Ultraviolet vision and mate choice in the guppy, Poecilia reticulata

Smith, Elizabeth Jane January 2001 (has links)
No description available.
28

Molecular structure and predissociation dynamics studied using absorption spectroscopy and ion imaging

Howie, Wendy Helen January 2001 (has links)
No description available.
29

Corona discharge and the visualisation of electric fields

Miller, J. A. January 1988 (has links)
No description available.
30

Design, synthesis and assessment of highly functionalised phthalocyanines

Jafari-Fini, Ali January 1997 (has links)
No description available.

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