Lignocellulosic biomass is a promising alternative to non-renewable fossil fuel resources for the sustainable production of fuels and chemicals. Levulinic acid (LA) is considered to be a versatile platform chemical which can be derived from biomass and further upgraded to high-value products like levulinate esters. In this work, the direct chemical conversion of lignocellulosic biomass to ethyl levulinate (EL) through LA was studied in collaboration with Gascon Biomass Research Inc. in an effort to valorize their surplus of lignocellulosic feedstock obtained from biomass recycling activities. A novel one-pot, biphasic, acid-catalyzed hydrolysis-esterification process developed by Prof. Tom Baker's lab (uOttawa Chemistry) was used. Kinetic analyses of the overall reaction pathway and major reaction steps were performed to investigate the effect of reaction conditions such as time, temperature, alcohol concentration, and catalyst concentration and evaluate the kinetic and thermodynamic parameters. Reactions were well modeled by power law rate equations with applicability of the Arrhenius expression and exhibited nearly first-order dependence with respect to each of the corresponding reactants and catalyst, as expected. Kinetic studies of LA esterification to various levulinate esters showed that the reaction is endothermic, endergonic, non-spontaneous, and non-rate-limiting. Increased alcohol alkyl chain length and branching reduced the thermodynamic favourability of LA esterification, likely due to steric effects. Process considerations such as reactor pressure, LA and EL partitioning, solvent:feedstock ratio, solvent recycling, and alternative feedstocks were investigated through various lab-scale studies and simulation case studies with UniSim® Design. The results of experimental studies informed the development of a preliminary potential process flow diagram consisting of eleven batch slurry reactors under agitation in parallel. The product streams feed into a continuous separation process composed of flash vessels and distillation columns to separate and purify the various products, intermediates, unconsumed reactants, and recoverable catalyst and solvent. This work ultimately informs decisions regarding future pilot-scale experiments, process design, and optimization for the envisioned large-scale biorefinery to produce EL.

No description available.

In biomechano-transducing, cellular generated tension can be measured by soft substrates based on polymers but these techniques are limited either by spatial resolution or ability to detect localised cell traction forces (CTF) due to their non-linear viscous behaviour under shear rates. A newly developed cell traction force transducer system based on cholesteryl ester lyotropic liquid crystals (LCTFT) was developed to sense localised traction forces of human keratinocyte cell lines (HaCaTs), in which the length of the deformation line induced represents the intensity of the CTF exerted. The physical properties of the cholesteryl ester based lyotropic liquid crystals (LLC) were characterised by using polarising microscopy, rheology, atomic force microscopy (AFM) based nano-indentation, spherical indentation, and micro-tensile tests. The interactions of LLC with cells were studied by using cell viability studies, cytochemical treatments, widefield surface plasmon resonance (WSPR) microscopy and various immuno-staining techniques. The results show that LLC is thermally stable (0 - 50 oC) and linearly viscoelastic below 10 % shear strain at shear rates of < 1 s-1. AFM nano and spherical indentations show a good agreement on the Young¿s modulus of both determined at ~110 kPa which is close to the elastic modulus of the epidermis. The Poisson¿s ratio of LLC was determined at ~0.58 by using micro tensile tests. The biophysical interaction studies indicated that LLC is biocompatible and allowed cell attachment. Cell relaxation technique by cytochalasin-B treatment suggested that the attachment and contraction of cells on LLC was due to the contractile activity of actin cytoskeletons that are mediated by focal adhesions. The staining experiments showed that cells consistently expressed the same suites of integrins (¿2, ¿3, ¿5 and ¿1) and ECM proteins (collagen type IV, laminin and fibronectin) on both glass and LLC coated substrates. Interfacial interaction of cells with LLC observed via the staining of actin and vinculin, and WSPR imaging suggest the association of marginal actin filaments and focal adhesions in attaching HaCaT cells to the LLC. Linear static analysis applied in the Finite Element model of focal adhesion-LC confirmed the compressive force patterns induced by cells. By applying cell relaxation techniques and Hooke¿s theorem, the force-deformation relationships of the LLC were derived and used for direct quantification of CTF in culture. The sensitivity of the LCTFT was implied by a wide range of CTF (10 - 140 nN) measured at high resolutions (~2 ¿m). Nonetheless, a custom-built cell traction force measurement and mapping software (CTFM) was developed to map CTF of single cells. Reliability of the LCTFT was evaluated by using a known pharmacological active cytokine, TGF-¿1, in inducing contraction of human keratinocytes. This study inferred internal consistency and repeatability of the LCTFT in sensing contraction responses of HaCaT cells in a concentration dependent manner of TGF-¿1. The overall LCTFT and CTFM software had shown good potential for use in the study of contraction and migration of keratinocytes. / Malaysia Ministry of Higher Education

No description available.

No / This study aimed at examining the biophysical characteristics of human derived keratinocytes (HaCaT) cultured on cholesteryl ester liquid crystals (CELC). CELC was previously shown to improve sensitivity in sensing cell contractions. Characteristics of the cell integrin expressions and presence of extracellular matrix (ECM) proteins on the liquid crystals were interrogated using various immunocytochemical techniques. The investigation was followed by characterization of the chemical properties of the liquid crystals (LC) after immersion in cell culture media using Fourier transform infrared spectroscopy (FTIR). The surface morphology of cells adhered to the LC was studied using atomic force microscopy (AFM). Consistent with the expressions of the integrins α2, α3 and β1, extracellular matrix proteins (laminin, collagen type IV and fibronectin) were found secreted by the HaCaT onto CELC and these proteins were also secreted by cells cultured on the glass substrates. FTIR analysis of the LC revealed the existence of spectrum assigned to cholesterol and ester moieties that are essential compounds for the metabolizing activities of keratinocytes. The immunostainings indicated that cell adhesion on the LC is mediated by self-secreted ECM proteins. As revealed by the AFM imaging, the constraint in cell membrane spread on the LC leads to the increase in cell surface roughness and thickness of cell membrane. The biophysical expressions of cells on biocompatible CELC suggested that CELC could be a new class of biological relevant material.

The dissertation takes as a point of departure that 1945 is usually mentioned as a start for a new type of Swedish children’s literature. In the majority of handbooks in and reviews of the history of Swedish children’s literature this is repeated as a fact. A reason for this is that three famous authors of children’s literature in Swedish all had their breakthrough this year: Lennart Hellsing, Tove Jansson and Astrid Lindgren. They are regarded as the most important examples of the new type of children’s literature. Especially Astrid Lindgren’s Pippi Långstrump [Pippi Longstocking] has been seen as a symbol for the free child and for the revolt against the adult world and the stiff rules of etiquette. At the same time as 1945 has been assigned as the birth date for a new children’s literature the general view of the preceding period, between the two world wars, has been that it was stagnant and uninteresting. In this study, the hypothesis was that the new did not emerge from an empty space. After extensive reading of children’s literature from the time between the wars it was discovered that there were new tendencies in this literature similar to those ascribed to the literature from the period after 1945. A more detailed analysis was performed comparing Astrid Lindgren’s Pippi Långstrump with works by the Swedish author Ester Blenda Nordström and the Danish author Karin Michaëlis’. The results show that the children’s literature produced between the wars was much more complex than previously stated and has several characteristics similar to the literature produced after 1945. As a consequence it seems necessary to modify the notion of 1945 as the definite starting point for the modern Swedish children’s book. A comparative analysis of the three authors is used as verification in the thesis. The analysis use among others the theories of Bachtin about the “popular laugh culture” and shows that the main characters in the books by Nordström and Michaëlis to the same extent as Pippi Långstrump illustrates the norm-breaking and independent child. The similarities between the work of Astrid Lindgren and Nordström and Michaëlis are obvious in terms of content as well as in expressions and type of language. The main focus in this dissertation is a textual analysis against a background of social context analysis. The conclusions state that there clearly were predecessors to the work of Astrid Lindgren. To simply state that 1945 was the year when the modern children’s book was born thus no longer seems relevant. / <p>Akademisk avhandling för avläggande av filosofie doktorsexamen i litteraturvetenskap vid Göteborgs universitet, som med tillstånd av</p><p>humanistiska fakultetsnämnden kommer att offentligen försvaras fredagen den 27 maj 2011, kl. 10 i Lilla Hörsalen, Humanisten, Renströmsgatan 6, Göteborg</p>

In biomechano-transducing, cellular generated tension can be measured by soft substrates based on polymers but these techniques are limited either by spatial resolution or ability to detect localised cell traction forces (CTF) due to their non-linear viscous behaviour under shear rates. A newly developed cell traction force transducer system based on cholesteryl ester lyotropic liquid crystals (LCTFT) was developed to sense localised traction forces of human keratinocyte cell lines (HaCaTs), in which the length of the deformation line induced represents the intensity of the CTF exerted. The physical properties of the cholesteryl ester based lyotropic liquid crystals (LLC) were characterised by using polarising microscopy, rheology, atomic force microscopy (AFM) based nano-indentation, spherical indentation, and micro-tensile tests. The interactions of LLC with cells were studied by using cell viability studies, cytochemical treatments, widefield surface plasmon resonance (WSPR) microscopy and various immuno-staining techniques. The results show that LLC is thermally stable (0-50 °C) and linearly viscoelastic below 10% shear strain at shear rates of < 1 s⁻¹. AFM nano and spherical indentations show a good agreement on the Young's modulus of both determined at ~110 kPa which is close to the elastic modulus of the epidermis. The Poisson's ratio of LLC was determined at ~0.58 by using micro tensile tests. The biophysical interaction studies indicated that LLC is biocompatible and allowed cell attachment. Cell relaxation technique by cytochalasin-B treatment suggested that the attachment and contraction of cells on LLC was due to the contractile activity of actin cytoskeletons that are mediated by focal adhesions. The staining experiments showed that cells consistently expressed the same suites of integrins (α2, α3, α5 and β1) and ECM proteins (collagen type IV, laminin and fibronectin) on both glass and LLC coated substrates. Interfacial interaction of cells with LLC observed via the staining of actin and vinculin, and WSPR imaging suggest the association of marginal actin filaments and focal adhesions in attaching HaCaT cells to the LLC. Linear static analysis applied in the Finite Element model of focal adhesion-LC confirmed the compressive force patterns induced by cells. By applying cell relaxation techniques and Hooke's theorem, the force-deformation relationships of the LLC were derived and used for direct quantification of CTF in culture. The sensitivity of the LCTFT was implied by a wide range of CTF (10 - 140 nN) measured at high resolutions (~2 μm). Nonetheless, a custom-built cell traction force measurement and mapping software (CTFM) was developed to map CTF of single cells. Reliability of the LCTFT was evaluated by using a known pharmacological active cytokine, TGF-β1, in inducing contraction of human keratinocytes. This study inferred internal consistency and repeatability of the LCTFT in sensing contraction responses of HaCaT cells in a concentration dependent manner of TGF-β1. The overall LCTFT and CTFM software had shown good potential for use in the study of contraction and migration of keratinocytes.

The main focus of this thesis is the interpretation of the view of the world in two of the short stories of Argentinean writer Roberto Arlt. The thesis is based on essay of the foundation, evolution and theory of short story. Both the global point of view and the perspectives of Hispano-American authors Horacio Quiroga, Julio Cortázar and Jorge Luis Borges are considered. In addition, this work describes Argentinean society at the turn of the 19th into the 20th century, the society being the main period of Arlt's pieces. The context of the literature in Buenos Aires in the 1920s and 1930s is also described to introduce the writer's position among his contemporaries. A brief introduction of Roberto Arlt's biography and writings is included as background. All of these factors are addressed in the analysis of the short stories "The Little Hunchback" and "Ester Primavera." The analysis is targeted at the style and method used to create the short stories and about the acts and life situations of its characters. Arlt's integration of lower social class and colloquial language in literature, his interest in the individual existence, and the gradual elimination of the boundary between reality and fiction, inspired many writers of the following generation.

A celulose é o biopolímero mais abundante da Terra. Ela contempla muitos dos requisitos desejados para substituição de polímeros sintéticos oriundos de petróleo. Entretanto, a insolubilidade da celulose em água e em solventes orgânicos comuns e a sua decomposição antes da fusão impedem seu processamento por extrusão. Uma solução para esse problema é a preparação de derivados de celulose que possam ser processados por extrusão ou regeneração em não solvente. Nesse ponto, os ésteres de celulose, utilizados há décadas, possuem destaque apresentando grande interesse comercial. Contudo, o contínuo estudo dos ésteres de celulose quanto aos métodos de preparação, de suas propriedades e o desenvolvimento de novos compostos se faz necessário para melhorar e ampliar suas aplicações. Sendo assim, essa tese de doutoramento contribuiu para a química dos ésteres de celulose das seguintes formas: (i) estudo de solventes para síntese de ésteres de celulose em condições reacionais homogêneas; e (ii) síntese, caracterização e moldagem de ésteres mistos de celulose com estrutura controlada. Dentro do primeiro tema, soluções binárias de dimetilsulfóxido (DMSO) e líquidos iônicos (ILs) a base de 1-metilimidazol (acetato de 1-(1-butil)-3-metilimidazólio, C4MeImAc; acetato de 1-(2-metóxietil)-3-metilimidazólio, C3OMeImAc) foram avaliadas como solvente para dissolução e acilação (síntese de acetato de celulose e benzoato de celulose) de celulose sob condições reacionais homogêneas. O foco dessa etapa de trabalho foi verificar se a presença de oxigênio etéreo na cadeia lateral do anel imidazólio favorecia a dissolução e acilação da celulose, uma vez que ele é mais básico que o correspondente grupo metilênico. Surpreendemente, o C4MeImAc apresentou melhor capacidade de dissolução de celulose e os ésteres de celulose nele preparados possuem maior grau de substituição. Para compreensão dessa aparente contradição foram utilizadas as técnicas de reologia; de espectroscopia de 1H e 13C NMR de soluções de celobiose em IL/DMSO; e de solvatocromismo (avaliação da acidez e basicidade de Lewis). Todos essesresultados indicam uma menor interação entre a celulose e o IL contendo cadeia alcóxi e corroboram os dados recém-publicados de cálculos teóricos, que indicam a ciclização, via formação de ligações de hidrogênio intramolecular, do cátion C3OMeIm+. Na tentativa de impedir a ciclização do cátion imidazólio e consequentemente melhorar as propriedades do IL contendo cadeia alcóxi, ILs metilados nas posições 1 e 2 do anel imidazólio foram testados. Apesar de a metilação melhorar a capacidade dos ILs para dissolução e acilação da celulose, não foi observado o efeito esperado para a presença do oxigênio etéreo na cadeia lateral do IL. No segundo tema de estudo, ésteres mistos de celulose (CellCarboxy/Ts) contendo grupo tosilato (com grau de substituição fixo, DSTs &#8776; 1,0) e grupos carboxilatos (com grau de substituição variável, DSAcyl) com diferentes hidrofobicidades (acetato, butanoato, hexanoato) foram sintetizados em meio homogêneo de cloreto de lítio/N,N-dimetilacetamida (LiCl/DMAc). A dependência no DSAcyl das propriedades de superfície (polaridade empírica, acidez e basicidade de Lewis; ângulo de contato e energia de superfície) desses ésteres de celulose foi determinada e apresentam correlações simples. Os Cell-Carboxy/Ts também foram caracterizados quanto às suas propriedades térmicas verificando-se que o aquecimento dos ésteres leva à saída dos grupos acila antes do grupo tosilato e que a temperatura de decomposição desses ésteres é menor que a de fusão. Portanto, os Cell-Carboxy/Ts só podem ser moldados por regeneração a partir de soluções. Sendo assim, as técnicas de gotejamento de solução de éster de celulose (solvente acetona) em não solvente (água) e de eletrofiação de solução de Cell-Carboxy/Ts (solvente acetona/DMAc) foram otimizadas para preparação de microesferas e microfibras, respectivamente. As estruturas obtidas apresentaram diâmetro médio de 240 ± 35 nm e 230 ± 20 nm, respectivamente. A aplicabilidade da espectroscopia no infravermelho e no UV-VIS foi avaliada para determinação do DSAcyl dos ésteres mistos obtendo-se resultados satisfatórios. Esses métodos são interessantes, pois permitem a economia de amostra (ca. de 1 % da massa necessária no método tradicional de titulação), o que é relevante em estudos exploratórios de ésteres de celulose onde poucos gramas de amostra são preparados. / Cellulose is most abundant biopolymer in the Earth. It complies with many desired requirements for substitution of petroleum-based polymers. However, cellulose is insoluble in water and common organic solvents and decomposes before undergoes melt flow, which prevents its extrusion processing. One possible solution for this problem is the preparation of cellulose derivatives that can be process by extrusion or by regeneration into non-solvents. In this point, cellulose esters, used for decades, stand out showing great commercial interest. In spite of their long use, the continuous research on cellulose ester focused on new synthetic methods, determination of properties and development of new compounds is necessary to improve and expand their commercial application. Therefore, this PhD thesis contributes to the cellulose esters chemistry in the following way: (i) study of solvents for synthesis of cellulose esters in homogenous reaction conditions (HRC); and (ii) synthesis, characterization and shaping of cellulose mixed esters with controlled structure. In the first approach, binary mixtures of dimethyl sulfoxide (DMSO) and ionic liquids (ILs) based on 1-methylimidazole (1-(1-butyl)-3-methylimidazolium acetate, C4MeImAc; 1-(2-methoxyethyl)-3-methylimidazolium acetate, C3OMeImAc) were evaluated as solvent for cellulose dissolution and acylation (synthesis of cellulose acetate and cellulose benzoate) under HRC. This part of project aim was verify if the presence of ether oxygen on side chain of imidazolium ring can favored the cellulose dissolution and acylation, once it is more basic than the corresponding methylene group. Surprisingly, the C4MeImAc shows higher ability to dissolves cellulose and the biopolymer esters prepared in it have higher degree of substitution. In order to understand this apparent contradiction, were employed the following techniques: rheology, 1H and 13C NMR spectroscopy of celobiose solution in IL/DMSO; and solvatochromism (evaluation of Lewis acidity and basicity). All results indicate a lower interaction between cellulose and the IL with alkoxy side chain and corroborate the recently published data of theoretical calculation which proposed the cyclization of C3OMeIm+ cation, via intramolecular hydrogen bond. In attempt to avoid the imidazolium cation cyclization and consequently improve the properties ofIL containing alkoxy side chain, ILs methylated at positions 1 and 2 of imidazolium cation were tested. Despite methylation improve the IL ability on cellulose dissolution and acylation, the expected effect for the presence of ether oxygen on IL side chain was not observed. In the second part of this study, cellulose mixed esters (CellCarboxy/Ts) containing tosylate unit (fixed degree of substitution, DSTs &#8776; 1.0) and carboxylate groups (variable degree of substitution, DSAcyl) with different hydrophobicity (acetate, butanoate, hexanoate) were synthesized in homogeneous medium of lithium chloride/N,N-dimethylacetamide (LiCl/DMAc). The dependence on DSAcyl of surface properties (empical polarity, Lewis acidity and basicity, contact angle, surface energy) of Cell-Carboxy/Ts was determined and show simple correlation. The thermal properties of Cell-Carboxy/Ts were also evaluated verifying that the heating of these cellulose esters promotes the scisson of acetate group before the tosylate ones. Further Cell-Carboxy/Ts decompose before they undergo melt-flow, so these cellulose esters can be shaped only by regeneration from their solution. In this way, Cell-Carboxy/Ts was shaped into microspheres and microfibers using the techniques of dropping (acetone solution into water) and electrospinning (acetone/DMAc solution), respectively. The structures obtained have average diameter of 240 ± 35 nm e 230 ± 20 nm, respectively. The applicability of infrared and UV-VIS spectroscopies to determine the DSAcyl of cellulose mixed esters was evaluated obtaining satisfactory results. These methods are interesting because they use few amount of sample (about 1 % of weight required by traditional titration method). The sample economy is relevant in exploratory studies of cellulose esters since they are carried out on few grams of sample.

Atualmente os dados epidemiológicos sobre a exposição ao crack no Brasil são preocupantes, principalmente entre crianças e adolescentes na capital de São Paulo. É sabido que o crack apresenta um potencial maior que o correspondente a outras formas de uso da cocaína para causar dependência. Apesar de haver numerosos estudos e métodos validados para identificação e quantificação de cocaína em fluidos biológicos, o mesmo não ocorre para a caracterização de seu uso na forma de crack. Todos os métodos descritos para diferenciação de exposição ao crack empregam equipamentos de alto custo e que nem sempre são viáveis para a realidade econômica dos laboratórios públicos brasileiros. Este trabalho objetivou desenvolver e aplicar um método eficiente e viável economicamente para identificação e quantificação dos indicadores de uso do crack em amostras de urina provenientes do Núcleo de Toxicologia Forense do Instituto Médico-Legal de São Paulo. O método mostrou-se linear na faixa de interesse (intervalo dinâmico de 0,2 a 20 µg/mL) para éster metilanidroecgonina. Os limites de detecção e quantificação foram de 0,1 e 0,2 µg/mL respectivamente e os testes de estabilidade mostraram-se satisfatórios (degradação menor que 10% após 30 dias). Foram analisadas trinta e sete amostras de urina sendo que onze foram positivas para o indicador escolhido mostrando a utilidade do método no esclarecimento de ocorrências no âmbito forense, no sentido de indicar se a intoxicação da cocaína se deu por esta forma de exposição (utilização de crack). / At the present time, epidemiologic data on the prevalence of crack in Brazil is alarming, principally as it concerns young children and teenagers in the capital city of São Paulo of São Paulo State. It is known that with crack there is a greater potential for dependency than that corresponding to other forms of cocaine use in causing dependency. Although numerous studies and methods have been validated for the identification and quantification of cocaine in biological fluids, the same is not true for the characterization of its use in the form of crack. All the methods described for differentiating the exposure to crack employ very expensive equipment, which is not always viable to the economic reality of the Brazilian public laboratories. This study had as its objective the development and application of a method that is efficient and economically viable for the identification and quantification of products of crack biomarkers in urine samples from the Forensic Toxicology Lab of the Legal Medicine Institute of São Paulo. The method showed to be linear in the interest range (dynamic range from 0.2 to 20 µg/mL ) for anhydroecgonine methyl ester. The limits of detection and quantification were 0.1 and 0.2 µg/mL respectively, and the stability tests proved to be satisfactory (less than 10% lost after 30 days). Thirty seven urine samples were analyzed such that these 11 were positive for the chosen biomarker, showing the usefulness of the method for clarification purposes in the forensic environment, in the sense of indicating whether the intoxication from cocaine was of this form of exposition (crack use).