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Application of radioisotopes to polymer chemistry : investigation of radiolabelled atom transfer polymerizationLong, Mark January 2016 (has links)
The use of the radioisotope 14C in polymer chemistry has been reviewed, showing how it has been used to investigate the mechanistic aspects of free radical polymerizations, and the use of polymers in other scientific disciplines such as environmental, physical, chemical and medical sciences. An overview of the application of fluorescent spectroscopy to polymer chemistry is also reported. It covers the fundamentals of fluorescence chemistry, its application and the potential problems of the use of fluorescent labels in polymer chemistry. The application of radioisotopes to atom transfer radical polymerisation (ATRP) to investigate the fate of initiators used in the ATRP of 2-hydroxypropyl methacrylate (2- HPMA) is also reported. By using 14C radiolabelled initiators, radio thin layer chromatography (Radio TLC) and the liquid scintillation counting of fractions, collected from gel permeation chromatography (GPC), the fate of the initiating species where monitored during the polymerization of samples of 14C poly(2-HPMA), with degrees of polymerization of 10, 25 and 50 was assessed. GPC and Radio TLC, data showed that there was an under-utilisation of the initiator, 16% clearly observable at high monomer conversion (>97%), which could result in the initiation of new chains at monomer conversions of >90% and as late as 300 minutes after the polymerisation had started. These results contradict ATRP theory which states all initiator is consumed immediately at the commencement of the polymerization. 14C poly(2-HPMA) was also used to determine the efficiencies of the polymer purification methods, flash chromatography and precipitation. Although repeated precipitation increased fractionation, it was shown to be superior to flash chromatography in removing residual unreacted or terminated initiator. Finally, the possible effects of fluorescent labels on adsorption of low molecular weight 14C poly(DEAEMA) onto real surfaces (filter paper, photo graphic paper and hair) from aqueous solutions at pH=2 were investigated. Three low molecular weight samples of 14C poly(DEAEMA) were prepared by ATRP using 14C labelled initiators synthesized from alcohols of increasing hydrophobicity i.e. methyl, benzyl and 9-hydroxyfluorene (fluorescent label). The levels of adsorption were determined using phosphor imaging, oxidation of organic samples and liquid scintillation counting. Results indicated that differences in the chemistry of the polymer end groups can affect adsorption of the 14C poly(DEAEMA) and polymer assembly at the air/water interface. There was greater adsorption of polymers with a fluorescent end group. The increasing deposition was attributed to the increasing hydrophobicity of the polymer end group. Moreover, the controlled placement of one fluorescent label per polymer chain can influence the polymer’s properties, prompting the question, is the use of fluorescent groups to assess polymer behaviour and properties viable?
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DESENVOLVIMENTO DE MARCADORES MICROSSATÉLITES PARA Hoplias malabaricus (BLOCH, 1794) / DESENVOLVIMENTO DE MARCADORES MICROSSATÉLITES PARA Hoplias malabaricus (BLOCH, 1794)Gondim, Sara Giselle de Cassia Alexandre 08 April 2010 (has links)
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Previous issue date: 2010-04-08 / Hoplias malabaricus is a characiforme fish (family Erythrinidae) with a wide distribution in
the Neotropical region. The species has been considered by several authors as a group of
species in urgent need of a taxonomic revision. Under this context, genetic studies are needed
in order to increase the amount of information available for this species. Microsatellite
markers are codominant, multiallelic, abundant and well distributed throughout the genome,
and therefore are efficient to evaluate the genetic variability in natural populations. Also for
conservation and managment studies. This study uses a strategy of development of primers
for microsatellite regions based on the sequencing of random fragments from a genomic
library "shotgun" for the detection of microsatellite regions in H. malabaricus. From 864
sequences obtained, I found 78 microsatellite regions that allowed the construction of pairs of
primers. These regions are composed of different types of repeat motifs, including
dinucleotide, trinucleotídes, tetranucleotídes and pentanucleotídes. Alleles varied in size from
136 to 236 base pairs. This shows that the strategy of random sequence from libraries
"shotgun" is interesting to obtain repetitive regions with different motives. From 78 pairs of
primers found, 25 were synthesized for standardization and characterzation. Of these 25, 14
had satisfactory standard of amplification, and among these, six (Hmal-9, Hmal-23, Hmal-33,
Hmal-34, Hmal-46 and Hmal-60) showed polymorphisms. Considering the 14 loci evaluated,
the observed heterozygosity (Ho) had a mean of 0.054 and expected heterozygosity (He) had
a mean value equal to 0.246. Among the loci that showed polymorphisms, only the reported
Hmal-9 showed significant deviations for the test of adherence to the proportions expected for
the Hardy-Weinberg. The strategy of development of starters from library shotgun was
efficient for the detention of different types of regions microssatélites in the genome of the
species Hoplias malabaricus exists low polimorfismos in the 14 locos microssatélites
evaluated in 48 individuals. / A espécie Hoplias malabaricus, pertencente à família Erythrinidae, representa uma das
espécies de peixes characiformes com maior distribuição na região Neotropical. O grupo vem
sendo considerado por diversos autores como um conjunto de espécies que necessita de uma
revisão quanto à classificação. Para tanto, dentre outros, são necessários estudos genéticos,
aumentando a quantidade de informações disponível para a espécie. Os marcadores
microssatélites, por serem codominantes, multialélicos, abundantes e bem distribuídos ao
longo do genoma, são eficientes para avaliar a variabilidade genética em populações naturais
e para a realização de estudos de genética com aplicação em manejo e conservação. Este
estudo utiliza uma estratégia de desenvolvimento de iniciadores para regiões microssatélites
que se baseia no sequenciamento aleatório de fragmentos provenientes de uma biblioteca
genômica shotgun para a detecção de regiões microssatélites, em H. malabaricus (traíra).
Das 864 sequências obtidas, foram encontradas 78 regiões microssatélites que possibilitaram
a construção de pares de iniciadores. Estas regiões são compostas por vários tipos de motivos
de repetição, incluindo dinucleotídios, trinucleotídios, tetranucleotídios, pentanucleotídios. Os
alelos apresentaram amplitude de variação de tamanho entre 136 a 236 pares de bases. Isto
mostra que a estratégia de sequenciamento aleatório a partir de bibliotecas shotgun é
interessante para a obtenção de regiões repetitivas com diferentes motivos. Dos 78 pares de
iniciadores encontrados, 25 foram sintetizados para padronização e caraterização. Destes 25,
apenas 14 apresentaram padrão de amplificação satisfatório, e dentre estes, seis (Hmal 9,
Hmal 23, Hmal 33, Hmal 34, Hmal 46 e Hmal 60) apresentaram polimorfismos.
Considerando os 14 locos avaliados, a heterozigosidade observada (Ho) apresentou uma
média igual a 0,054 e a heterozigosidade esperada (He) apresentou um valor médio igual a
0,246. Dentre os locos que apresentaram polimorfismos, apenas Hmal-9 apresentou desvios
significativos para o teste de aderência às proporções esperadas para o equilíbrio de Hardy-
Weinberg. A estratégia de desenvolvimento de iniciadores a partir de biblioteca shotgun foi
eficiente para a detecção de diferentes tipos de regiões microssatélites no genoma da espécie
Hoplias malabaricus. Existe um baixo polimorfismos nos 14 locos microssatélites avaliados
em 48 indivíduos da espécie Hoplias malabaricus.
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Rozbor příčin požárů vzniklých v Jihočeském kraji v letech 2009 - 2013 od elektrických zařízení a návrh opatření ke zlepšení stavu / Analysis of the causes of fires from electrical equipment caused in the South Bohemia region in the years 2009-2013 and the concept of precautions to improve the situationBENEDIKT, Ondřej January 2014 (has links)
The thesis is divided into two parts, theoretical and empirical. In the first, the author explains the important terms for processing the empirical part. He deals with the theory of fire and summary of the general rules. He also deals with finding out the causes of fire and the computer program "Statistical monitoring of events", all the data were taken here. The chapter provides a general overview of el. devices, classification, history and possible danger. A very important of this part is the division of el. initiators explain. the terms such as el. short circuit, impedance, el. spark, el. arc, overcurrent, car-el. and its application in vehicles. Separately the author deals with atmospheric and ESD. The first objective was to analyze the causes of fires from el. devices in the South Bohemian Region (SBR). The second objective was the proposal of arrangements to improve the situation. The author determined two hypotheses: 1. The most common cause of fires of el. devices in the SBR is the el. short circuit. 2. The most frequent fires of el. devices in the SBR are the fires of vehicles. At the end of the first part, the author outlined the methodology. For processing the empirical part , he chose a quantitative research. The research was carried out by using the one-dimensional statistical analysis of data. The author created the list of literary sources based on literature gained from research libraries, the Fire Rescue Service (FRS) of the SBR, territorial department Strakonice and el. sources available on the internet. All the data the author gained SME of the FRS of the SBR. Within empirical part, the author first carried out the overall statistics of fires from el. initiators. The results show that in the period of 2009 - 2013 there was an increase in number of fires from el. initiators from 7,14 % to 14,97 %, it means more than double compared to a total amount of all fires, which have a decreasing tendency. Then he deals with proportions among particular initiators of fire. These data indicate that the most abundant initiator is car-el. and its application in vehicles. Other significant initiators are el. short circuit and impedance. Other initiators carry a much smaller proportion of the total number of fires. Then follow damages and salvage values caused. Salvage values in each of the monitored years are far greater than the damages, about 80 %. The author continues with the amount of people killed and injured, there is a big difference. Throughout the given period there were 5 people killed in fires from el. initiators, 51 people injured. For the total fires are numbers logically higher, in years 2009 - 2013 were 363 people injured and 51 killed. Then follows a part in which the author deals with individual initiators represented by el. short circuit, impedance, el. spark, el. arc, overcurrent, car-el. and its application in vehicles, atmospheric discharge and ESD. In the empirical part, there are also included initiators, which cannot be further specified. After processing the gained statistical data it comes to the discussion, in which the author analyzes particular tables and graphs, problems, which occurred with their solution and expresses to previously established hypotheses. The first hypothesis was refuted, the second confirmed. The author proposed measures to improve the situation, as there was detected a lack of security measures. The results of the thesis will be a contribution to the FRS of the Czech Republic, especially to the Prevention Department, pedagogical purposes or the general public in the context of preventive educational activities. After implementation of any of my proposals, using the same research it is possible to determine whether the implementation of the proposal has a positive impact on the number of fires, injured and killed people or on an amount of damages in the coming years.
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Uso de benzodioxolas em sistemas de fotoiniciação de adesivos odontológicos / Thesis (Doctorate) Post Graduate Program, School of Dentistry, Federal University of Pelotas / RS, BrazilLima, Giana da Silveira 10 July 2009 (has links)
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Previous issue date: 2009-07-10 / The objective of this study was to evaluate the effectiveness of benzodioxole derivatives as co-initiators of radical polymerization of experimental self-etching
adhesive systems. To compose the experimental self-etching adhesive systems a primer, containing methacrylate monomers and solvents, was developed. A monomer mixture, based on 50 wt % of Bisphenol A glicidyl dimethacrylate (Bis-GMA), 25 wt% of triethyleneglycol dimethacrylate (TEGDMA) and 25 wt% of 2-hydroxyethyl methacrylate(HEMA), was used as a model dental adhesive resin. Camphorquinone (CQ) 1 mol % was used as a photoinitiator to initiate polymerization. Different co-initiators (1,3- benzodioxole and piperonyl alcohol) and concentrations (0.25, 0.50, 1, 2, 4, 8, 16 mol %) were used in a model dental adhesive resin, to compose the experimental groups. Additionally, tertiary amine (EDAB) was used as co-initiator in the control group. The physical, chemical and mechanical properties and characteristics of the polymer obtained for the experimental adhesives (ABDO, APA, AEDAB) were evaluated using polymerization kinetics, sorption and solubility, flexural strength and elastic modulus.
The microtensile bond strength (µTBS) to enamel and dentin, and fracture mode were investigated. Adicionalmente morphological analysis of the dentin bonding Interface
were evaluated. The results indicated that the BDO and PA were effective co-initiators for the photoinitiator system based on CQ. Comparisons between the benzodioxole
derivative co-initiators and traditionally used amine EDAB, showed similar performance in the kinetics of polymerization, flexural strength, water sorption and solubility of the model dental adhesive resin evaluated. In the microtensile bond strength dentin means
were higher than enamel and mixed failures were predominant. APA showed higher bond strengths than AEDAB, while ABDO showed intermediate data. The hybrid layer for
all groups was shown to be shallow (1-2 µm thick). No appreciable differences in homogeneity were detected along the bonded interface. BDO and PA were feasible alternatives to conventional amine as co-initiator of radical polymerization, moreover, as these benzodioxoles are found in the human diet, this characteristic made them more promising and advantageous to use in dental adhesive resin formulations than amine. / O objetivo deste estudo foi avaliar a efetividade de componentes derivados de benzodioxolas, como co-iniciadores da polimerização radicalar de um adesivo autocondicionante experimental. Para compor sistemas adesivos autocondicionantes experimentais foi desenvolvido um primer, composto por monômeros metacrilatos e solventes. O adesivo foi formulado utilizando uma resina adesiva modelo, composta por 50% de bisfenol A glicidil dimetacrilato (Bis-GMA), 25% de 2-hidroxietil metacrilato (HEMA) e 25% de trietilenoglicol dimetacrilato (TEGDMA), em massa. Canforoquinona (CQ) na concentração 1% molar foi utilizada como fotoiniciador da polimerização da resina modelo. Os grupos experimentais foram formulados com diferentes coiniciadores na resina adesiva: 1,3-benzodioxola (BDO) e álcool piperonílico (AP), em diferentes concentrações molares (0.25, 0.50, 1, 2, 4, 8, 16 %). Adicionalmente um grupo com amina terciária, etil,4-dimetilamino benzoato (EDAB) como co-iniciador, foi formulado como controle. Características e propriedades físicas, químicas e mecânicas do polímero obtido pelos adesivos experimentais foram avaliadas utilizando as metodologias de cinética de polimerização, sorção e solubilidade, resistência à flexão e módulo de elasticidade. A resistência de união à microtração (MPa) ao esmalte e à dentina, com a caracterização do tipo de fratura foi investigada. Adicionalmente, análise morfológica da interface adesiva em dentina foi avaliada. Os resultados indicaram que o BDO e PA foram co-iniciadores efetivos para sistemas fotoiniciadores à base de canforoquinona (CQ). Comparações entre os adesivos experimentais com co-iniciadores derivados de benzodioxolas (ABDO e AAP) e amina (AEDAB), mostraram performance similar na avaliação da cinética de polimerização, resistência à flexão, sorção e solubilidade da resina adesiva modelo avaliada. Na avaliação da resistência de união ao esmalte e à dentina, foi detectada diferença estatística e houve predominância de falhas mistas. APA apresentou maior resistência de união que AEDAB, enquanto ABDO mostrou resultados intermediários. A camada híbrida para todos os grupos apresentou uma espessura entre 1 e 2 Vm. Não foi observada diferença na homogeneidade da interface adesiva em dentina. BDO e PA se revelaram alternativas viáveis à amina como co-iniciadores para a polimerização radicalar. Ademais, estas benzodioxolas são mais promissoras e vantajosas que as aminas, por sua biocompatibilidade e presença na dieta humana
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Kompaktní město - aneb co nového se může ještě dít v Brně mezi nádražími / Compact Town - or what new is able to yet be done in Brno among railway stationsBřezovská, Markéta January 2009 (has links)
Rather than a new masterplan I developed a strategy how to deal with a complicated area between the two Brno train stations. The land on the south of the city center has not been used for almost 100 years. There is a plan today, caused by removal of the main station to the south and introduction of the new city-train, to build up the area. The strategy I propose is based on the critical analysis of the current state of the area, of the plans that the city of Brno has, on the principles of the “compact city”, on my research on the potential users of the site and a study of life of 7 (imaginary) different potential user groups in the future, within the specific time horizon.
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Novel Possibilities for Advanced Molecular Structure Design for Polymers and NetworksFinne, Anna January 2003 (has links)
Synthetic and degradable polymers are an attractive choicein many areas, since it is possible to control the way in whichthey are manufactured; more specifically, pathways tomanipulate the architecture, the mechanical properties and thedegradation times have been identified. In this work,L-lactide, 1,5-dioxepan-2-one and ε-caprolactone were usedas monomers to synthesize polymers with different architecturesby ring-opening polymerization. By using novel initiators,triblock copolymers, functionalized linear macromonomers andstar-shaped aliphatic polyesters with well-defined structureshave been synthesized. To synthesize triblock copolymers,cyclic germanium initiators were studied. The polymerizationproceeded in a controlled manner although the reaction rateswere low. To introduce functionality into the polymer backbone,functionalized cyclic tin alkoxides were prepared and used asinitiators. During the insertion-coordination polymerization,the initiator fragment consisting mainly of a double bond wasincorporated into the polymer backbone. The double bond wasalso successfully epoxidized and this gave unique possibilitiesof synthesizing graft polymers with precise spacing. Themacromonomer technique is a very effective method for producingwell-defined graft polymers. Spirocyclic tin initiators weresynthesized and used to construct star-shaped polymers. Thestar-shaped polymers were subsequently crosslinked in apolycondensation reaction. These crosslinked structures swelledin water, and swelling tests showed that by changing thestructure of the hydrogel network, the degree of swelling canbe altered. A first evaluation of the surface characteristicsof the linear triblock copolymers was also performed. AFManalysis of the heat-treated surfaces revealed nanometer-scalefibers and tests showed that keratinocytes were able to growand proliferate on these surfaces. / QC 20100602
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Massenspektrometrische und quantenchemische Studien radikalischer Polymerisationen zur Initiierung mit Peroxycarbonaten / Mass-spectrometric and quantumchemical studies of radical polymerizations for the initiation with peroxycarbonatesJanßen, Olaf 23 January 2009 (has links)
No description available.
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Critique de la modernité et philosophie de l'enracinement : la médiation des valeurs dans l'oeuvre de Simone Weil / Critique of the Modernity and the Philosophy of Root : the mediation of Values in Simone Weil's worksEnyegue abanda, Fabien Mathurin 12 February 2013 (has links)
Basée sur l’idée de progrès, la science moderne, d’inspiration cartésienne, est perçue par Simone Weil comme la principale cause de la crise moderne des valeurs. Sous-tendue par le mouvement droit, elle a perdu le principe d’analogie et s’est, de la sorte, dessaisie du monde ambiant des réalités quotidiennes. Aussi apparaît-elle non seulement comme à la source du scientisme, de la croyance en une raison scientifique autonome et du culte rendu aux applications techniques, mais aussi à l’origine du capitalisme industriel, du communisme révolutionnaire, du totalitarisme, de l’effondrement de l’ordre axiologique universel traditionnel concomitant à la crise de la civilisation. Les conséquences issues de ce mouvement de déracinement n’ont pas seulement conduit à l’oppression prolétarienne et coloniale ou au modernisme comme primat des valeurs d’innovation sur les valeurs de tradition, mais surtout à l’oppression généralisée et à l’oubli des structures axiologiques primordiales universelles que sont l’Etre, la Nécessité, le Passé, le Surnaturel. Fondé sur une dialectique structurelle déracinement-enracinement, pesanteur-grâce, le discours philosophique de Simone Weil sur la modernité poursuit un double enjeu. Sans se démarquer de la raison philosophique immanente, elle s’attelle à la fois à la dénonciation des propensions et défaillances qu’offrent les valeurs illusoires modernes d’argent, d’algèbre, de machinisme, d’impérialisme, de révolution, de démocratie, qu’à la conception d’une philosophie de la médiation des valeurs apte à contribuer à la renaissance d’une culture d’attention au capital axiologique de l’humanité. En effet, la modernité n’apparaissant plus que comme synonyme de crise des valeurs, il convient de tirer au clair ce piège qui fait de l’homme l’esclave de ses propres productions en y entreprenant une herméneutique ouverte non seulement au principe ontologique de nécessité, au-delà de toute projection avant-gardiste, mais surtout à une herméneutique des civilisations inspiratrices de l’humanité, en dehors de tout misonéisme passéiste, où le Surnaturel s’atteste dans sa plénitude comme critérium des valeurs authentiques et principe de médiation témoignant de l’enracinement de toutes choses dans l’être. Sans être en opposition avec les impératifs de découverte, d’invention et de développement, la philosophie weilienne de la médiation des valeurs se dévoile dans sa posture et sa validité comme une philosophie d’inspiration universelle à l’enracinement des peuples, des cultures et des nations, attentive à une pensée permanente des rapports entre la tradition et l’innovation, l’universalité et l’historicité. / Based on the idea of progress, the modern science, inspired by Descartes, is seen by Simone Weil as the primary cause of the modern crisis of values. Sustained by a linear movement, this science has lost the principle of analogy and, by consequent, it has lost its bindings with the surrounding world of everyday reality. Also, this science shows itself not only as the source of scientism, this belief in an independent scientific reason and the cult of the technical applications, but also as the source of industrial capitalism, of the revolutionary communism, of the totalitarianism, of the collapse of the traditional axiological order simultaneously to the crisis of civilization. Theses consequences resulting from the movement of uprooting not only led to the proletarian and the colonial oppression and to the modernism as the priority of the values of innovation on the values of tradition, but especially to a generalized oppression and the forgetting of the primordial universal axiological structures: the Being, the Need, the Past and the Supernatural.Based on a structural dialectic, the dislocation and the rooting, the fall and salvation, the philosophical discourse on modernity of Simone Weil seeks a double stake. Without a delimitation of the reason of the immanent philosophy, she is equally attached to the denunciation of the propensities and the failures of the modern illusory values of the money, of the algebra, of the machinery, of the imperialism, of the revolution, of the democracy, and to the conception of a philosophy of the mediation of values able to contribute to the rebirth of a culture attentive to the axiological capital of the humanity. Indeed, if the modernity appears no more as a synonym of the crisis of values, we must clarify this trap that makes the man the slave of his own productions by a hermeneutic open not only to the ontological principle of necessary, beyond any avant-garde projection, but principally a hermeneutic of the inspired civilizations of the humanity, without any outdated misoneism, where the Supernatural is attested in its fullness as criterion of the authentic values and as a principle of mediation reflecting the roots of all things in the Being. Without being in a conflict with the requirements of the discovery, of the invention, of the progress, the weilian philosophy of values mediation reveals itself as a philosophy of universal inspiration, founding the rooting of peoples, of cultures and of nations, paying permanent attention to the relationship between the tradition and the innovation, between the universality and the historicity.
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