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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.
871

CONTROLE DE MOFOS EM SALAMINHO E SALAME TIPO ITALIANO, ATRAVÉS DE DESINFECÇÃO POR NATAMICINA, ULTRAVIOLETA, OZÔNIO E IONIZAÇÃO DO AR / CONTROL IN MOULD SALAMI BY DISINFECTION IN ULTRAVIOLET, OZONE, NATAMYCIN AND AIR IONIZATION

Vieira, Débora Craveiro 30 April 2013 (has links)
The presence of molds on the surface of salami may bring undesirable effects during the maturation process of salami, causing negative effects on the development of color, aroma and flavor. Where there is often the need for removal of this gut, the final product, resulting in losses in production, reducing yield and increasing the cost of the product. This way, this study is justified the search of a new technology in the market to control fungal. With this objective was to follow the evolution of mold surface of salami (Ф=42 mm) and the italian salami (Ф=75 mm), observing the effect of the application of antifungal natamycin, UV, ozone and air ionization. Evaluate the physico-chemical, microbiological and sensory and monitor the shelf life of salami in different decontamination methods followed.The main fatty acids found after treatments were oleic acid, palmitic acid, linoleic acid and stearic acid, causing an increase in saturated fatty acids after the storage period (120 days), proving that there was an increase in lipid oxidation without differ in storage time. All the procedures affected thesensorial quality, which has been evaluated by the attributes color, odor, flavor and texture after 120 days.When evaluating different methods for the control of mold surface of salami, observed that treatment of natamycin 0,5% (SLS5) and ionization (SLSION) had a maximum growth of 103 CFU/cm2 being that the most effective method for the salami was treatment with natamycin 0.5% had a maximum growth of 1.90 x102 CFU/cm2. As for, the Italian salami treatments using natamycin 0.5% (SIG5), ozonizer (SIGOZO) and ionizer (SIGION) were the most effective methods, had a maximum growth of 103 CFU/cm2. Therefore, this study showed that treatments using natamycin 0.5% and ionization in air is an alternative to control mould salami thin and thick gauge of salamis providing the highest microbiological safety and sensory acceptance. / A presença dos mofos na superfície do salame pode trazer efeitos indesejáveis durante o processo de maturação, causando efeitos negativos no desenvolvimento de cor, aroma e no sabor. Muitas vezes há a necessidade de remoção desta tripa, ao final do processo, resultando em perdas na produção, reduzindo o rendimento e elevando o custo de produto. Dessa forma, o presente trabalho justifica-se pela busca de uma nova tecnologia no mercado para o controle fúngico. Com isso, objetivo do trabalho foi acompanhar a evolução do mofo em superfície de salaminho (Ф=42 mm) e dos salames tipo italiano (Ф=75 mm) observando o efeito antifúngico na aplicação de natamicina, ultravioleta, ozônio e ionização do ar. Foi avaliado as características físico-químicas, microbiológicas e sensoriais e acompanhar a vida de prateleira dos salames produzidas com diferentes métodos de descontaminação. Observou-se que em todos os tratamentos não houve comprometimento do processo tecnológico, nem dos parâmetros legais físico-químicos e microbiológicos. Os principais ácidos graxos encontrados foram ácido oléico, ácido palmítico, ácido linoléico e o ácido esteárico (18:0), observando aumento nos ácidos graxos saturados após no período de armazenamento, demonstrando que houve um aumento na oxidação lipídica, sem diferir no tempo de armazenamento. Todos os tratamentos afetaram a qualidade sensorial que foi avaliada através dos atributos cor, odor, sabor e textura após os 120 dias. Ao avaliar os diferentes métodos para o controle de mofos em superfície de salaminho, conclui-se que os tratamentos utilizando natamicina 0,5% e ionização foram os métodos mais efetivo, que apresentou baixa carga fúngica (1,90 x102 UFC/cm2). Já para o salame tipo italiano os tratamentos utilizando natamicina 0,5% (SIG5), ozonizador (SIGOZO) e o ionizador (SIGION) foram os métodos mais efetivos, mantendo-se 103 UFC/cm2. Portanto, este estudo indicou que os tratamentos utilizando natamicina 0,5% e ionização em ar é uma alternativa para controle fúngicos em salame de calibre fino e grosso proporcionando salames de maior segurança microbiológica e com aceitação sensorial.
872

UV-Induced Melanoma Mouse Model Dependent on Endothelin 3 Over-Expression

Benaduce, Ana Paula 20 October 2014 (has links)
Melanoma is one of the most aggressive types of cancer. It originates from the transformation of melanocytes present in the epidermal/dermal junction of the human skin. It is commonly accepted that melanomagenesis is influenced by the interaction of environmental factors, genetic factors, as well as tumor-host interactions. DNA photoproducts induced by UV radiation are, in normal cells, repaired by the nucleotide excision repair (NER) pathway. The prominent role of NER in cancer resistance is well exemplified by patients with Xeroderma Pigmentosum (XP). This disease results from mutations in the components of the NER pathway, such as XPA and XPC proteins. In humans, NER pathway disruption leads to the development of skin cancers, including melanoma. Similar to humans afflicted with XP, Xpa and Xpc deficient mice show high sensibility to UV light, leading to skin cancer development, except melanoma. The Endothelin 3 (Edn3) signaling pathway is essential for proliferation, survival and migration of melanocyte precursor cells. Excessive production of Edn3 leads to the accumulation of large numbers of melanocytes in the mouse skin, where they are not normally found. In humans, Edn3 signaling pathway has also been implicated in melanoma progression and its metastatic potential. The goal of this study was the development of the first UV-induced melanoma mouse model dependent on the over-expression of Edn3 in the skin. The UV-induced melanoma mouse model reported here is distinguishable from all previous published models by two features: melanocytes are not transformed a priori and melanomagenesis arises only upon neonatal UV exposure. In this model, melanomagenesis depends on the presence of Edn3 in the skin. Disruption of the NER pathway due to the lack of Xpa or Xpc proteins was not essential for melanomagenesis; however, it enhanced melanoma penetrance and decreased melanoma latency after one single neonatal erythemal UV dose. Exposure to a second dose of UV at six weeks of age did not change time of appearance or penetrance of melanomas in this mouse model. Thus, a combination of neonatal UV exposure with excessive Edn3 in the tumor microenvironment is sufficient for melanomagenesis in mice; furthermore, NER deficiency exacerbates this process.
873

Investigations into the epidemiology and aetiology of cancers of the skin

Wallingford, Sarah January 2014 (has links)
The cancers of the skin, melanoma and the keratinocyte cancers, basal cell andsquamous cell carcinomas (BCC and SCC), are among the most common cancersin white populations. While ultraviolet radiation (UVR) is their principal cause,links with non-UVR-related factors have also been noted. Ultimately, theinteraction of these elements results in malignancy however, understanding oftheir specific contributions remains incomplete. This thesis reports findings fromsix studies aiming to investigate gaps in current knowledge of the role of UVR andnon-UVR-related risk factors on skin cancer. The papers are groupedaccording to the aspects of skin cancer epidemiology and aetiology they address. The first two papers address the descriptive epidemiology of melanoma inEngland, a country with low ambient solar UVR. They arise from ecologicalstudies using national melanoma registration data and document rising trends inmelanoma incidence by anatomic site (Paper 1), and by region of residence andsocio-economic deprivation (Paper 2). Their findings were consistent with thesuggestion that increases in recreational UVR exposure are driving rises inmelanoma rates. These results emphasise both the need to closely monitor UVRexposure and melanoma trends and the importance of public health campaigns. The second group of three papers considers the assessment of associations ofnutritional factors with keratinocyte cancer. Two studies use data from aprospective cohort to evaluate the relationship between dietary intake (Paper 3)and blood concentrations (Paper 4) of omega-3 and omega-6 polyunsaturatedfatty acids (PUFA) in relation to BCC and SCC risk. Associations with both PUFAtypes were observed. In addition, Paper 5, a three-way correlational assessment,demonstrated that questionnaire and blood circulating levels of omega-3 PUFAwere highly correlated with measures of skin bioavailability. Collectively, thesestudies give evidence for associations of these nutrients with skin cancer and forthe utility of both intake and biomarker measures for assessing the relationships. The final paper explores the relationship between a widely cited non-UVR riskfactor, namely scars and cancers of the skin. It reports a systematic review of allpublished observational studies quantifying this association. While innumerablecase reports were found, quantitative analyses were rare. The review identifieda major gap in the literature where knowledge of scar malignancies is notevidence-based, but rather founded mainly on cumulative anecdotal reporting. Taken together, this body of published work highlights the largely unrecognisedcomplexity of the aetiology of cancers of the skin. Future research must bebroad in scope in order to advance understanding of the interaction betweenUVR and other risk factors and to provide a base for health messages aimed atreducing the burden of these malignancies.
874

PANCHROMATIC IMAGING OF A TRANSITIONAL DISK: THE DISK OF GM AUR IN OPTICAL AND FUV SCATTERED LIGHT

Hornbeck, J. B., Swearingen, J. R., Grady, C. A., Williger, G. M., Brown, A., Sitko, M. L., Wisniewski, J. P., Perrin, M. D., Lauroesch, J. T., Schneider, G., Apai, D., Brittain, S., Brown, J. M., Champney, E. H., Hamaguchi, K., Henning, Th., Lynch, D. K., Petre, R., Russell, R. W., Walter, F. M., Woodgate, B. 22 September 2016 (has links)
We have imaged GM Aurigae with the Hubble Space Telescope, detected its disk in scattered light at 1400 and 1650 angstrom, and compared these with observations at 3300 angstrom, 5550 angstrom, 1.1 mu m, and 1.6 mu m. The scattered light increases at shorter wavelengths. The radial surface brightness profile at 3300 angstrom shows no evidence of the 24 au radius cavity that has been previously observed in submillimeter observations. Comparison with dust grain opacity models indicates that. the surface of the entire disk is populated with submicron grains. We have compiled a. spectral energy distribution from 0.1 mu m to 1 mm. and used it to constrain a model of the star + disk system that includes the submillimeter cavity using the Monte Carlo radiative transfer code by Barbara Whitney. The best-fit model image indicates that the cavity should be detectable in the F330W bandpass if the cavity has been cleared of both large and small dust grains, but we do not detect it. The lack of an observed cavity can be explained by the presence of submicron grains interior to the submillimeter cavity wall. We suggest one explanation for this that. could be due to a planet of mass <9 M-J interior to 24 au. A unique cylindrical structure is detected in the far-UV data from the Advanced Camera for Surveys/ Solar Blind Channel. It is aligned along the system semiminor axis, but does not resemble an accretion-driven jet. The structure is limb. brightened and extends 190 +/- 35 au above the disk midplane. The inner radius of the limb. brightening is 40 +/- 10 au, just beyond the submillimeter cavity wall.
875

[en] TREATMENT OF EFFLUENTS CONTAINING FREE CYANIDE THROUGH THE SYSTEM H2O2/UV / [pt] TRATAMENTO DE EFLUENTES CONTENDO CIANETO LIVRE ATRAVÉS DO SISTEMA H2O2/UV

ADRIANA CINOPOLI GONCALVES 10 March 2005 (has links)
[pt] O presente trabalho teve como objetivo estudar o tratamento de efluentes contendo cianeto livre através do sistema H2O2/UV e selecionar as condições operacionais mais adequadas para uma maior eficiência do processo. Para isso, foram empregadas soluções sintéticas de KCN com características de pH e concentração similares às condições de um efluente industrial real. O fotorreator utilizado nos testes de oxidação foi um reator cilíndrico de seção anular, equipado com uma lâmpada de baixa pressão de 28 W concêntrica com emissão em 254 nm, onde a solução ficava diretamente em contato com a mesma. Este fotorreator foi acoplado a um sistema de refrigeração que mantinha a temperatura de operação em 25oC.As variáveis avaliadas foram concentração inicial de cianeto em solução, pH inicial da solução, potência de UV irradiada e razão molar [H2O2]/[CN-]. Para soluções contendo uma concentração inicial de cianeto igual a 100 ppm, foi possível atingir uma eficiência remoção de 99,9 por cento em 25 minutos, em pH igual a 9,5, com uma razão molar [H2O2]:[CN-] igual a 3. Para efluentes contendo uma concentração inicial de cianeto igual a 300 ppm, nas mesmas condições operacionais, alcançou-se a mesma eficiência em 30 minutos. / [en] The present work had the objective of studying the treatment of effluents containing free cyanide through the system H2O2/UV, and of selecting the best operational conditions for best efficiency of the process. For that, it was employed synthetic solutions of KCN with characteristics of pH and concentration similar to those of a real effluent. The photoreactor employed in the oxidation tests was a cylindrical reactor of annular section, equipped with a concentrical low pressure lamp of 28 W with emission in 254 nm, where the solution was in direct contact with the lamp. This photoreactor was coupled with a cooling system which kept the operation temperature at 25oC. The evaluated variables were initial cyanide concentration in solution, initial pH of the solution, power of radiated UV and molar ratio [H2O2]/[CN-]. For solutions containing an initial concentration of cyanide equal to 100 ppm, it was possible to reach a removal efficiency of 99.9 per cent in 25 minutes, in pH equal to 9.5, with a molar ratio of [H2O2]:[CN-] equal to 3. For effluents containing an initial concentration of cyanide equal to 300 ppm, at the same operational conditions, it was possible to achieve the same removal efficiency in 30 minutes.
876

Effects of HALSs and Nano-ZnO Worked as UV Stabilizers of Polypropylene

Lu, Xinyao 12 1900 (has links)
This work reports the outdoor weathering performance of ultraviolet (UV)-stabilized polypropylene (PP) products (using PP resins from Encore Wire). Different hindered amine light stabilizers (HALSs) and nano-ZnO were used to stabilize PP-film-based formulations that were exposed under UV light for 6 weeks simulating for in harsh outdoor weather of Dallas, Texas, USA in 2016. Characterization of the exposed PP film products was done in terms of mechanical and friction spectroscopic properties. The PP film formulations were divided into 15 categories based on the type of HALS and nano-ZnO incorporated. This was done to derive meaningful comparison of the various film formulations. Following exposure under UV light, the lifetimes of certain formulations were determined. On the basis of the mechanical and friction properties, it was determined that generally, the HALS or nano-ZnO stabilized PP film give better properties and if those two kinds of UV stabilizers can work together.
877

Nonlinear UV Laser Build-up Cavity: An Efficient Design

Rady, Nicholas Henry 05 1900 (has links)
Using the concept of the build-up cavity for second harmonic generation to produce 243nm laser light, an innovative cavity is theoretically explored using a 15mm length CLBO crystal. In order to limit the losses of the cavity, the number of effective optical surfaces is kept to only four and the use of a MgF2 crystal is adopted to separate the harmonic and fundamental laser beam from each other. The cavity is shown to have an expected round trip loss of five tenths of a percent or better, resulting in a conversion efficiency greater than 65%.
878

Xeroderma Pigmentosum A Deficiency Results in Increased Generation of Microvesicle Particles in Response to Ultraviolet B Radiation

Christian, Lea Rajeshkumar 28 May 2021 (has links)
No description available.
879

Visible-blind and solar-blind ultraviolet photodiodes based on (InxGa1-x)2O3

Zhang, Zhipeng, von Wenckstern, Holger, Lenzner, Jörg, Lorenz, Michael, Grundmann, Marius 06 August 2018 (has links)
UV and deep-UV selective photodiodes from visible-blind to solar-blind were realized based on a Si-doped (InxGa1–x)2O3 thin film with a monotonic lateral variation of 0.0035<x<0.83. Such layer was deposited by employing a continuous composition spread approach relying on the ablation of a single segmented target in pulsed-laser deposition. The photo response signal is provided from a metal-semiconductor-metal structure upon backside illumination. The absorption onset was tuned from 4.83 to 3.22 eV for increasing x. Higher responsivities were observed for photodiodes fabricated from indium-rich part of the sample, for which an internal gain mechanism could be identified. VC 2016 AIP Publishing LLC.
880

Chlorophyll Fluorescence Probe of Ultraviolet-B Photoinhibition of Primary Photoreactions in Intact Leaves

Nowak, Robert S. 01 May 1980 (has links)
Damage to primary photosynthetic reactions caused by environmental stress can be assessed by measurement of chlorophyll fluorescence induction in intact leaves. This approach was applied in studies of ultraviolet-B photoinhibition of photosynthesis in Pisum sativum L. and Rumex patientia L. leaves. At ultraviolet-B dose rates insufficient to cause inhibition of net photosynthesis, changes in the magnitude of fluorescence transients did occur, which suggested direct effects on chloroplast pigments in Pisum and inhibition of photosynthetic electron transport between the photosystems in both species. Leaves of these two species subjected to a much higher dose rate had a significant reduction of net photosynthesis and changes in the magnitude of fluorescence transients that indicated partial loss of water-splitting capability and direct effects on chloroplast pigments. Ultraviolet radiation-induced changes of photosynthetic thylakoid membranes may be ultimately responsible for these disruptions of the primary photosynthetic reactions.

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