Les profils de viabilité sur surface, de virus non enveloppés : murine minute virus (MVM), coxsackievirus B4 (CVB4), virus simien 40 (SV40), et de virus enveloppés : virus de grippe A (H1N1), et virus herpès simplex de type 1 (HSV-1), ainsi que la résistance à la chaleur et aux ultraviolets C (UVc) de ces virus ont été étudiés.Pour déterminer la viabilité de MVM, CVB4, H1N1 et HSV-1 sur surface, 50 µL de suspension virale ont été déposées sur des couvercles de boites de Pétri et séchés sous un flux d’air avant d’être récupérés et titrés sur des lignées cellulaires appropriées. Les virus enveloppés ont persisté moins de 5 jours alors que CVB4 et MVM restent infectieux pendant plusieurs semaines. Cependant, les cycles répétés de séchage et de remise en suspension ont eu un effet plus virucide sur CVB4 que sur H1N1 et HSV-1. Aucun effet des répétitions de ces cycles n’a été observé sur le titre infectieux du MVM. Quand il est exposé au séchage, les concentrations initiales d’albumine de sérum bovin, de sérum de veau fœtal et de chlorure de sodium, ont un impact sur la survie de CVB4. Dans un milieu riche en protéines, CVB4 a été plus facilement inactivé par le séchage, alors qu’en présence de chlorure de sodium le pouvoir virucide du séchage a été réduit. Ces résultats montrent que la résistance des virus vis-à-vis du séchage, n’est pas due à une hétérogénéité de populations virales, mais peut être influencée par la composition du milieu et la concentration des composants.Nous avons évalué la résistance thermique de MVM, CVB4, H1N1 et HSV-1 contenus dans des gouttelettes. Quatre microlitres de suspension virale ont été déposés sur une surface chauffée et exposés à des températures comprises entre 70 et 130°c pendant 0 à 90min, selon le virus, avant d’être titrés. Clairement, MVM a été plus résistant que H1N1, lui-même plus résistant que HSV-1 et CVB4. Pour la première fois, l’inactivation de particules virales contenues dans des gouttelettes exposées à des températures supérieures à 100°C a été étudiée. Il apparaît que le chauffage peut provoquer un effet plus rapidement virucide que décrit précédemment.La résistance aux UVc (254nm) de MVM, CVB4, H1N1, HSV-1 et SV40 contenus dans des gouttelettes a été évaluée. Les virus à ADN double brins (HSV-1 et SV40) restaient infectieux après une exposition à 60mJ/cm² d’UVc, tandis que les virus à ARN (H1N1 et CVB4) et un virus à ADN simple brin (MVM) ont été totalement inactivés par une exposition inférieure ou égale à 35mJ/cm² d’UVc. De plus l’effet des UVc combiné à la chaleur sur la viabilité de MVM a été déterminé. Le titre infectieux de MVM, contenu dans une gouttelette a été totalement inactivé après une exposition à 27mJ/cm² d’UVc. Le chauffage (20s à 100°C) a provoqué une réduction modérée du titre viral de MVM (-1.8 log10TCID50), alors que le chauffage suivi par une exposition à 17mJ/cm² d’UVc entraine une inactivation complète.En conclusion, nos études montrent que les virus peuvent persister pendant des jours voire des semaines sur une surface hydrophobe. Le profil de résistance des virus vis-à-vis du séchage, n’est pas dû à une hétérogénéité de populations virales, comme l’ont montré les résultats obtenus avec CVB4. De plus, dans la mesure où la composition du milieu joue un rôle dans la viabilité des virus exposés au séchage, la persistance des virus devrait être étudiée dans des milieux naturels plutôt que dans des milieux définis. L’impact de temps d’exposition courts à la chaleur sur les virus contenus dans de petits volumes de suspension a été déterminé. La résistance thermique de H1N1 jusqu’à 100°C, supérieure à celle d’HSV-1, un autre virus enveloppé, et à celle de CVB4 un virus non-enveloppé a été observée. Une inactivation virale efficace peut être obtenue en combinant une exposition aux UVc et à la chaleur comme le montrent les résultats obtenus avec MVM. / The pattern of viability of non-enveloped viruses, minute virus of mice (MVM), coxsackievirus B4 (CVB4), and simian virus 40 (SV40) and enveloped-viruses, influenza A virus (H1N1), and herpes simplex virus type 1 (HSV-1) onto surfaces and their resistance to heating and to ultraviolet C (UVc) exposure have been investigated. To determine the viability of MVM, CVB4, H1N1 and HSV1 on surface, fifty microliters of viral suspension were applied onto petri dish lids and dried under air flow of biosafety cabinet. The recovered viral preparations were titered on appropriate cell cultures. Enveloped viruses persisted for less than 5 days while CVB4 and MVM persisted for weeks. However, repetitive cycles of drying and resuspension had more virucidal effect on CVB4 than on H1N1 and HSV-1. No effect of these repetitive cycles on infectious titer of MVM was recorded. When exposed to drying, initial concentrations of bovine serum albumin, foetal calf and sodium chloride (NaCl) had an impact on the viability of CVB4. In a protein rich medium, CVB4 was more likely inactivated by drying whereas in presence of NaCl, the impact of drying was reduced. Thus, it appears that the resistance of viruses toward drying is not due to a heterogeneity of viral populations, but it can be influenced by media composition and components concentrations.Heat inactivation of viruses was reported, however, the thermal resistance of viruses in droplets has not been studied. We evaluated the pattern of heat resistance of MVM, CVB4, H1N1 and HSV1 contained in droplets. Four microliters droplets containing viruses were applied onto warmed surface obtained by using a self-made heating device. Viral suspensions were exposed to temperatures ranging from 70 to 130°C for 0 to 90 min depending on the virus, and then the recovered viral preparations were titered. Clearly, MVM was more resistant than H1N1 that was more resistant than HSV-1 and CVB4. For the first time, the inactivation of viral particles contained in drops exposed to temperatures higher than 100°C has been investigated. It appears that heating can have an unexpected faster virucidal effect than previously described. The resistance to ultraviolet C (UVc) (254nm) of MVM, CVB4, H1N1, HSV-1 and SV40 contained in droplets has been evaluated. Double-stranded DNA viruses (HSV-1 and SV40) were still infectious after exposure to 60 mJ/cm² UVc, while RNA viruses H1N1, CVB4 and single-stranded DNA virus MVM were fully inactivated when they were exposed to a dose equal to or lower than 35 mJ/cm² UVc. Moreover the effect of UVc (254 nm) combined with heating onto the viability of MVM was determined. The infectious level of MVM suspension droplets applied onto petri dish lids was fully inactivated when exposed to 27 mJ/cm² UVc. Heating (100°C for 20s) provoked a moderate reduction of infectious level (-1.8 log10TCID50) of MVM, whereas heating followed by UVc exposure (17 mJ/cm²) resulted in a full inactivation.In conclusion, our studies show that viruses can persist for days or even weeks on dry hydrophobic surfaces. The pattern of resistance of viruses toward drying is not due to a heterogeneity of viral population as shown by results obtained with CVB4. In so far as media composition play a role in the viability of viruses exposed to drying, the persistence of viruses in natural media (clinical or environmental), instead of defined media, should be investigated. The impact of short time exposure to heat onto the infectivity of viruses contained in a small volume of suspension has been determined. The thermal resistance of H1N1 up to 100°C, higher than the one of HSV1 another enveloped virus, and CVB4 a non-enveloped virus has been observed. An efficient viral inactivation can be obtained by combining UVc exposure and heating as shown by results obtained with MVM.

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Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Chad T. Miller / Kimberly A. Williams / Intumescences are a physiological disorder characterized by hypertrophy and possibly hyperplasia of plant cells. Many plant species are susceptible to intumescence development, but the specific causative factors remain uncertain. Ultimately, this disorder results in the death of the affected cells. Previous observations and research suggest that the quality and quantity of light to which plants are exposed may be a factor in development of the disorder. The purpose of the first study was to assess the preventive effect of UVB radiation on intumescence development in ornamental sweet potato (Ipomoea batatas). Two sweet potato cultivars, ‘Sidekick Black’ and ‘Ace of Spades,’ were grown under four light treatments of 1) Normal; 2) UVB; 3) UVB-Blocked; 4) Full-Spectrum. The ‘Ace of Spades’ cultivar was highly susceptible to intumescence development, while ‘Sidekick Black’ was much less susceptible to the disorder. For ‘Ace of Spades,’ the addition of UVB radiation significantly reduced the number of leaves affected with intumescences when compared to plants grown under the other light treatments. This study indicates a cultivar-specific effect of UVB light in minimizing intumescence development on ornamental sweet potato, therefore suggesting a potential genetic component in intumescence susceptibility. Many plant species are prone to similar physiological disorders in which lesions develop on the leaf tissue. Nomenclature for such lesions has varied significantly in the literature. Interchangeably using these terms causes confusion as to whether these names refer to the same or different disorders. The objective of the second study was to characterize the development of lesions on ornamental sweet potato (Ipomoea batatas ‘Blackie’), tomato (Solanum lycopersicum ‘Maxifort’) and interspecific geranium (Pelargonium בCaliente Coral’). Light microscopy, field emission scanning electron microscopy (FESEM), and digital photography were used to observe lesion development on each species. Lesions on ornamental sweet potato predominately involved the hypertrophy of the palisade parenchyma through the upper epidermis, while geranium lesions involved the hypertrophy of spongy parenchyma cells restricted by the lower epidermis. Tomato lesions involved both the hypertrophy and hyperplasia of the lower epidermis and spongy parenchyma. Thus, different species possess varied cellular responses when developing lesions due to physiological causes.

Selected fungal strain for production of raw-starch-digesting enzyme by solid state fermentation was improved by sequential exposures to γ-irradiation of Co60, ultraviolet and treatments with Nmethyl-N'-nitrosoguanidine. Mutant Aspergillus sp. CXN2-3A was chosen and its production of raw-starch-digesting enzyme (RSDE) was improved 2 folds higher than that of wild type. Optimal condition for the production of the enzyme using wheat bran as the substrate was accomplished for the CXN2-3A. With the optimal fermentation condition and the solid medium supplemented with urea and NH4NO3, CoSO4, Tween 80, 1% glucose, CXN2-3A produced RSDE 19.23 folds higher than wild type cultured in pre-optimized condition and un-supplemented medium. / Chủng nấm chọn lọc sản xuất enzyme thủy phân tinh bột bằng cách lên men trạng thái rắn, chủng nấm được cải thiện bằng chiếu xạ tia cực tím, tia Co60 và các phương pháp xử lí với N-methyl-N'-nitrosoguanidine. Mutant Aspergillus sp. CXN2-3A, đã được lựa chọn để sản xuất enzyme (RSDE) thủy phân tinh bột sống cải thiện cao hơn 2 lần so với chủng dại. Điều kiện tối ưu cho việc sản xuất các enzyme bằng cách sử dụng cám, lúa mì đã được thực hiện cho CXN2-3A. Với điều kiện lên men xốp tối ưu và bổ sung urê và NH4NO3, CoSO4, Tween 80, 1% glucose, CXN2-3A đã sản xuất RSDE cao gấp 19,23 lần so với kiểu dại ở cùng điều kiện.

Magister Scientiae - MSc (Chemistry) / The increasing cost of fossil fuel energy production and its implication in environmental pollution and climate change created high demand for alternative and renewable sources of energy. This has led to great interest in research in the field of photovoltaic or solar cells Due to the abundance of sunlight, the technology is sustainable, non-polluting and can be implemented at places where power demand is needed, for example in rural areas. Solar cell devices that have been commercialized are currently based on silicon technology, involving the use of monocrystalline, polycrystalline and amorphous silicon. Although they produce highly efficient solar cells, the cost of Si solar cells is too high. Second generation solar cell materials such as cadmium telluride and third generation materials such as perovskites and organic polymers have been receiving much attention recently. However, they lack the efficiency of Si solar cells. This research proposes the development of high energy conservation photovoltaic cells from novel low-cost organosilicon polymers. The aim was to develop novel highly branched organosilane polymers such as poly(3-hexythiophene), polydi(thien-2-yl)dimethylsilane, poly(3-hexyl- [2,2'] bithiophenyl-5-yl)-dimethyl-thiophen-2yl-silane) as electron donors along with zinc oxide nanorod as the electron acceptor which were able to bring the efficiency of the resultant photovoltaic cell close to that of current Si solar cell. / 2021-08-31

Orientador: Hung Kiang Chang / Resumo: O presente estudo explora a avaliação da distribuição de Light Non-Aqueous Phase Liquid (LNAPL) trapeado na zona saturada empregando a técnica de fluorescência induzida por laser (Laser-Induced Fluorescence – LIF). A área de estudo está localizada no município de Paulínia e tem sido investigada para contaminação por Querosene de Aviação (QAV) desde 2002. O equipamento Ultra-Violet Optical Screening Tool (UVOST®) foi utilizado por possuir a capacidade de detectar moléculas de Hidrocarbonetos Policíclicos Aromáticos (PAH) presentes no LNAPL. Foram realizados um teste piloto de bancada e 21 ensaios de perfilagem LIF em campo, incluindo monitoramento de nível d’água (NA) e nível de óleo (NO) sobrenadante em poços existentes. A perfilagem LIF foi empregada para definir com precisão a extensão lateral do LNAPL, bem como sua tipologia. Além disso, a integração de resultados de fluorescência, oscilação sazonal do NA, espessura de QAV e concentração de naftaleno conduziu para um entendimento mais claro da migração lateral e vertical do LNAPL em subsuperfície. Elevadas intensidades de fluorescência relacionadas ao QAV foram detectadas abaixo do NA na situação de descida do LNAPL em períodos de NA baixo, revelando migrações verticais pretéritas, e correspondem à presença de fase livre nesses períodos, previamente registradas em poços de monitoramento. Análises estatísticas dos quatro canais distintos (comprimentos de onda de 350 nm, 400 nm, 450 nm e 500 nm) mostraram forte correlação en... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present study explores the distribution evaluation of Light Non-Aqueous Phase Liquid (LNAPL) trapped in the saturated zone using Laser-Induced Fluorescence (LIF) technique. The study site is located in the Paulínia municipality and has been investigated for jet fuel contamination since 2002. Ultra-Violet Optical Screening Tool (UVOST®) was used for its capability in detecting Polycyclic Aromatic Hydrocarbon (PAH) molecules present in LNAPL. One pilot test and 21 LIF profiling tests were carried out in the field, including water table (WT) and floating oil level (OL) monitoring in existing wells. LIF profiling was employed to accurately define the lateral extension of weathered LNAPL, as well as its typology. In addiction, the integration of fluorescence results, seasonal fluctuation of WT, jet fuel thickness and naphthalene concentration led to a clear understanding of lateral and vertical migration of the LNAPL in the subsurface. High fluorescence intensities related to the jet fuel were detected below the WT in the situation of falling LNAPL in low WT season, revealing past vertical migration, and these correspond to the presence of free phase in periods of low WT, previously registered in monitoring wells. Statistical analysis of the four distinct channels (wavelength of 350 nm, 400 nm, 450 nm and 500 nm) showed correlation between the referred wavelengths in the presence of the contaminant, allowing differentiating with better refinement the horizons with the presence... (Complete abstract click electronic access below) / Doutor

The synergistic effect of nitric oxide toward dephosphorylation reactions involving phosphate esters was the subject of investigation in this research. Sodium nitroprusside under UV irradiations at 254nm, 365nm and white light was utilized as nitric oxide donor in solutions. The effects of cobalt trimethylenediamine and nitroprusside towards dephosphorylation of nitrophenylphosphate and pyrophosphate which were modeled as organophosphate ester substrates were also investigated. The activated substrate models showed more rate enhancement than the unactivated models in all cases. The direct interaction of nitric oxide with the phosphorus centre is presumed to be the reason for enhanced hydrolysis. This study demonstrates the possible role of nitric oxide in decontamination reactions of poorly biodegradable phosphate esters in the biosphere. / Chemistry / M. Sc. (Chemistry)

Depuis leurs découvertes dans les années 60 par Dewar, les composés BN-hétérocycliques ont subi un développement croissant, s’accentuant pendant la dernière décennie. Ce travail de thèse mené en collaboration avec le Pr S-Y LIU de Boston Collège (États-Unis) et le Pr L. WEBER de l’Université de Bielefeld (Allemagne), a permis la synthèse, ainsi que la caractérisation par spectroscopie photoélectronique à rayonnement UV de nouveaux systèmes. Dans une première partie représentée par les chapitres II, III et IV, nous abordons l’étude de la structure électronique des composés suivants : 1,2-dihydro-1,2-azaborine (1), N-Me-1,2-BN-toluene (2), N-Me-1,3-BN-toluene (3), 1,2-dihydro-1-aza-2-boranaphtalene (4), 1,2-dihydro-1-aza-2-boranthracene (5), 1,2-dihydro-1-aza-2-boranthracene (6), 1,2-dihydro-1-aza-2-boraphenanthrene (7), 1,3,2-benzodiazaborole (8), 1,9,8-benzodiazaborole (9), N-tert-butyl[1,3,2]diazaborolo[1,5-a]-pyridine (10), 1,3,2-trihydro[1,3,2]diazaborolo[1,5-a]-pyridine (11). Afin de compléter les propriétés physico-chimiques de ces nouveaux systèmes et d’aider à l’interprétation des spectres photoélectroniques, l’utilisation de calculs quantiques tels que la théorie de la fonctionnelle de la densité (DFT), la théorie fonctionnelle de la densité en fonction du temps (TD-DFT), la fonction de Green (OVGF), la méthode du troisième ordre partiel (P3), ou encore l’interaction de configuration (SAC-CI) ont été utilisées. Dans le Chapitre V, nous présentons une étude comparative entre les énergies ionisations théoriques et expérimentales. / Since the Dewar’s discovering in 60 years, the BN-heterocycles has experienced an important development during the last decade. This thesis presents our work on the synthesis and on the electronic structure characterization by Ultra-Violet photoelectron spectroscopy (UV-PES), followed in collaboration with the Pr SY LIU from the Boston College (USA) and the Pr L. WEBER from the University of Bielefeld (Germany). The first part corresponding to the chapter II, III and IV, describe the electronic structure analysis of: 1,2-dihydro-1,2-azaborine (1), N-Me-1,2-BN-toluene (2), N-Me-1,3-BN-toluene (3), 1,2-dihydro-1-aza-2-boranaphtalene (4), 1,2-dihydro-1-aza-2-boranthracene (5), 1,2-dihydro-1-aza-2-boranthracene (6), 1,2-dihydro-1-aza-2-boraphenanthrene (7), 1,3,2-benzodiazaborole (8), 1,9,8-benzodiazaborole (9), N-tert-butyl[1,3,2]diazaborolo[1,5-a]-pyridine (10), 1,3,2-trihydro[1,3,2]diazaborolo[1,5-a]-pyridine (11). In order to provide more information on the physical chemistry properties and to interpret the photoelectron spectra, the quantum chemical calculations of ionization energies have been followed using the Density Functional Theory (DFT), the Time-Dependent Density Functional Theory (TD-DFT), the Outer Valence Green’s Function (OVGF), the Partial third order (P3), the Symmetry Adapted Cluster-Configuration Interaction (SAC-CI). Moreover, the comparative analysis of theoretical and the experimental ionization energies are presented.