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Melt flow singularity in linear polyethylene : influence of molar mass, molar mass distribution and carbon-based fillersXu, Han January 2010 (has links)
In the recent past it has been found that a considerable pressure drop occurred during the extrusion of linear polyethylene in the course of capillary flow. The pressure drop resides within a narrow temperature window of one to two degrees Celsius. In this research the hydrodynamic condition and molecular origin of the extrusion window of linear polymer were investigated further. The advantage of the extrusion window, viz. smooth extrudate with less die swell ratio attained at low extrusion pressure and temperature, has potential in industrial applications. However, the extrusion window, corresponding to linear polyethylene (PE) with relatively low polydispersity (<7), has a narrow window temperature interval, circa 1~2°C, thus it could not be applied to industrial scale processing at the industrial scale. To have a fundamental insight and make the process industrially viable, research in this thesis was devoted to broaden the extrusion window to tolerate the thermal fluctuations in conventional processing. To achieve this goal molecular weight dependence of window temperature and flow criticalities is revealed. The hydrodynamic conditions of the extrusion window observed in a rate-controlled rheometer and stick-slip flow studied in a stress-controlled rheometer could be traced back to the same origin, viz. slip flow arises due to the disentanglement of adsorbed chains on capillary wall from free chains in the bulk. Secondly, a dual window effect was uncovered in the course of capillary flow of a bimodal PE, which is consistent with the window temperature dependence on molecular weight. Moreover, it was found that flow induced orientation within the window effect is even less than that observed in steady state flow at a relatively low shear rate. This implies that in the window region only relaxed free chains are extruded through the capillary die and most of the adsorbed chains, which could be disengaged from the entangled melt, remain sticking to the inner capillary wall. This observation is consistent with the hydrodynamic origin of high-surface-energy-die slip flow. Finally, a unimodal linear PE with extremely broad molecular weight distribution, i.e. polydispersity (PDI) is 27, showed a broad window effect, circa 8°C, at an appropriate apparent shear rate. The molecular origin of such a broad window effect is due to its broad molecular weight distribution. These results have further implications for energy efficient processing.
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Effect of β-glucan molecular weight and viscosity on the mechanism of cholesterol lowering in humansWang, Yanan 13 January 2016 (has links)
The cholesterol-lowering effect of mixed linkage (1→3) (1→4)-β-D-glucans (β-glucan) from barley has been documented, yet the underlying mechanism responsible for this action and factors influencing it, such as physicochemical properties of β-glucan and genetic background of an individual, remain unclear.As a component of dietary fibre, β-glucan also has the potential to shift the gut microbial community, however, whether alterations in the gut microbiota are associated with the physiological effects of β-glucan have yet to be determined.
This study was designed to assess the effects of β-glucan molecular weight (MW) and dose on loweringserum cholesterol levels and to elucidate its mechanism of action in human subjects. Additionally, this study examined gene-diet interactions as well as changes in the gut microbiota profile following consumption of barley foods. In a controlled four phase crossover trial, mildly hypercholesterolemic but otherwise healthy subjects (n =30) were randomly assigned to receive breakfasts containing 3g high MW (HMW), 5g low molecular weight (LMW), 3g LMW barley β-glucan or a control diet with wheat and rice (WR control), each for 5 weeks. The washout period between the phases was 4 weeks.
The consumption of 3g/d HMW diet lowered total cholesterol (TC) compared with WR control diet (P =0.0046), but not the LMW diet at either 3g/d or 5g/d. Individuals with the SNP rs3808607-G allele of CYP7A1 had greater TC reduction in response to 3g/d HMW β-glucan diet compared to the individuals carrying homozygous TT alleles (P<0.01). Cholesterol absorption and synthesis were not changed, but bile acid synthesis increased by 3g/d HMW diet compared to the control. Consuming 3g HMW/d β-glucan altered gut microbiota at the phylum and genus levels and the impacted microbial members was correlated with favorable shifts of cardiovascular disease risk factors.
In conclusion, physicochemical properties of β-glucan play critical roles in the cholesterol-lowering effect and gut microbiota alteration ability of β-glucan. The results suggest the increasing bile acid synthesis rather than inhibiting cholesterol absorption and synthesis is the mechanism responsible for the cholesterol reducing property of β-glucan.The altered microbiota profile by HMW β-glucan is associated with its physiological effect. / February 2016
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Kinetic and Thermodynamic Studies of Thrombin InhibitorsAbdel, Aziz May 28 February 2013 (has links)
Sulfated low molecular weight lignins (LMWLs), CDSO3 and FDSO3, designed recently as macromolecular mimetics of heparin, were found to exhibit potent anticoagulant activity. Small molecules based on the same scaffold, SBD and SBT, showed promising thrombin inhibition. We were able to address the mechanism of the inhibition using Michaelis-Menten kinetics. All the molecules were found to be allosterically impairing thrombin activity using either noncompetitive or uncompetitive mechanism. Absence of competition with hirugen, an exosite 1 ligand, and competition with polymeric heparin points to exosite 2 as the site of interaction for these inhibitors. Yet mixed competition results with other exosite 2 ligands indicated that the molecules utilize different sub-sites within exosite 2 for interaction. Site-directed mutagenesis was used to pin point the key residues important for inhibition. All of all positively charged exosite 2 residues were mutated one at a time to alanine to abolish its charge. The data showed that Arg93 and Arg175 are the major residues involved in CDSO3 binding. FDSO3 showed a progressively greater defect in inhibition with double point mutations, the triple mutant Arg93,97,101Ala displayed a 50 fold drop in inhibition. A single mutant, Arg173Ala, displayed 22-fold reduction in IC50 of SBD, while Arg233Ala was the only mutation that impaired SBT inhibition. This proves the fact that inspite of the structural similarity between the two polymers and the two small molecules, thtey do not share the same binding space in exosite 2. To understand the types of interactions involved in thrombin interaction with the polymers, we resorted to salt-dependence studies. This showed that CDSO3 had fewer ionic contacts with thrombin, with most of its binding energy derived from non-ionic interactions. FDSO3 on the other hand had a balanced contribution of ionic and non-ionic forces. Thermodynamic studies showed that both polymers have a positive ΔCp of binding, which proves the involvement of electrostatic forces and signals the burial of the polar residues on thrombin exosite 2. These molecules offer a rare chance to study thrombin allostery. Little is known about the interplay between exosite 2, active site and sodium binding site. The allosteric nature of inhibition indicated that, for the first time, a link is proven to exist between exosite 2 and the active site that could be used to inhibit the enzyme. The presence of sodium was found to enhance the binding of FDSO3 at exosite 2, which establish the energetic coupling between exosite 2 and sodium binding site. The results identify novel binding sub-sites within exosite 2 that are energetically coupled to thrombin’s catalytic function and linked to the sodium binding site. The design of high affinity small molecules based on LMWLs scaffold presents major opportunities for developing clinically relevant, allosteric modulators of thrombin.
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Bacterial poly-gamma-glutamic acid (γ-PGA) : a promising biosorbent of heavy metalsOgunleye, Adetoro O. January 2015 (has links)
Poly-γ-glutamic acid (γ-PGA) is a biopolymer made up of repeating units of L-glutamic acid, D-glutamic acid or both. γ-PGA is water soluble, non-toxic and biodegradable, and can be used safely in a variety of applications that are increasing rapidly. This study investigated the production of HMW γ-PGA by five Bacillus species (B. licheniformis 1525, B. licheniformis NCTC 6816, B. licheniformis ATCC 9945a, B. licheniformis ATCC 9945a and B. subtilis (natto) ATCC 15245) in GS, C and E media for the removal of heavy metals in wastewaters. The highest γ-PGA yields of 11.69 g/l and 11.59 g/l were produced by Bacillus subtilis (natto) ATCC 15245 in GS medium and medium C respectively. Upon characterization, γ- PGAs with different properties (crystallinity, acid/salt form and molecular weights ranging from 2.56 × 105 Da to 1.65 × 106 Da) were produced. The water soluble, non-toxic, HMW (Mw 1.65 × 106 Da) γ-PGA produced by B. subtilis (natto) ATCC 15245 in medium C was investigated as a sorbent for the removal of heavy metal ions including Cu2+, Zn2+, Ni2+, Cd2+ and Ag+. The results showed that the removal of metals by γ-PGA was more dependent on the concentration of γ-PGA than the solution pH. The highest metal ions removal of 93.50%, 88.13%, 90.21%, 90.56% and 86.34% by HMW γ-PGA were obtained for Cu2+, Zn2+, Ni2+, Cd2+ and Ag+ respectively. The presence of interfering metal ions could hinder the adsorption of individual metal ions by γ-PGA. The affinities of heavy metal ions for γ-PGA followed the order: Cu2+ > Zn2+ > Ni2+ > Cd2+. The effect of molecular weight of γ-PGA on metal removal was also investigated, and it was found that metal ion adsorption capacity of γ-PGA strongly depended on its molecular weight. The maximum amount (93.50%) of Cu2+ sorbed by HMW γ-PGA was higher compared to that (59.48%) sorbed by LMW γ-PGA. Isotherm models showed that the Redlich-Peterson best described the metal adsorption capacity of γ-PGA. It was also found that a multisite adsorption mechanism occurred via the complexation of metal ions with the free α-carboxyl and possibly the amide functional groups in γ-PGA.
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Technologie µLAS pour l'analyse et la purification d'ADN de haut poids moléculaire / µTechnology for High Molecular Weight DNA Analysis and PurificationMilon, Nicolas 19 March 2019 (has links)
Les techniques de séquençage ont connu un extraordinaire développement depuis plus de 40 ans et ont permis une véritable révolution dans le domaine de l’analyse biologique avec l’entrée dans l’ère de la génomique. Le développement de nouvelles méthodes de séquençage est néanmoins associé à des contraintes sur la préparation et le contrôle qualité des échantillons d’ADN. La 3ème génération de séquenceurs nécessite notamment l’utilisation de fragments d’ADN de très grande taille, supérieurs à 50000 paires de bases, qui sont complexes à préparer et à caractériser avec les techniques actuelles. Dans la perspective d’accélérer et d’améliorer ces procédures de préparation d’échantillons, nous avons développé un instrument basé sur la technologie µLAS permettant la concentration et la séparation de grands fragments d’ADN. Nous avons en particulier développé une méthode permettant la concentration, l’isolation et le séquençage de régions génomiques ciblées en les découpant avec l’enzyme de restriction Cas9. Nous avons également développé un prototype pour la purification d’ADN de haut poids moléculaire dans un mélange complexe. Cet instrument permet d’effectuer une vanne de sélection d’ADN accordable pilotée par champ électrique. Adaptée à l’enrichissement sélectif d’ADN selon sa taille de 200 bp à 50 000 bp, notre méthode permet d’effectuer une purification de 20 ng d’ADN génomique de taille supérieure à 20 kb avec la technologie de 10X Genomics. Nous avons ainsi montré le potentiel de la technologie µLAS dans l’analyse et la purification d’ADN de haut poids moléculaire. / In forty years only, DNA sequencing technologies triggered a revolution in biological analysis with the beginning of the genomic era. Nevertheless, this booming technological field is still hampered by unmet technological needs for DNA sample preparation and quality control. The most recent third generation sequencing technologies require very long DNA fragments of more than 50,000 base pairs, the manipulation and characterization of which remains a technological challenge. In the prospect of accelerating and improving state of the art protocols for sample preparation, we developed an instrument, based on the µLAS technology that allows the concentration and separation of high molecular weight DNA fragments with high sensitivity. With this technology, we developed a method for the isolation and sequencing of target genomic regions in complex genomes. We report the isolation, the sequencing and the assembly of a locus of 31.5 kb extracted from the genome of the plant Medicago Truncatula. We finally developed a prototype for high molecular weight DNA purification in complex samples, which is based on a size-accordable DNA valve for the size selection in the range 200 – 50,000 bp. In this manuscript we highlighted the relevance of µLAS technology for the analysis and purification of high molecular weight DNA.
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Estudo proteômico de vermes adultos machos e fêmeas de Schistosoma mansoni / Proteomic studies of male and female Schistosoma mansoni adult wormsRibeiro, Camila Macêdo 11 April 2011 (has links)
A esquistossomose é uma doença tropical negligenciada que atinge cerca de 200 milhões de pessoas em todo o mundo, abrangindo a América, a África, as Antilhas, o Oriente Médio e Próximo, além do Sudeste Asiático. A espécie encontrada no Brasil é a Schistosoma mansoni, onde se tem como tratamento típico a administração do Praziquantel ou da Oxamniquina. No entanto, sua característica de infecção se associa a saneamento básico precário e baixos padrões sócio-econômicos, de maneira que a reinfecção de doentes apresenta altas taxas de ocorrência, o que motiva a busca por fármacos ou vacinas antihelmíticas que superem esta dificuldade. Neste trabalho são utilizadas técnicas proteômicas para a identificação de proteínas que estejam potencialmente envolvidas na diferenciação entre os sexos, na interação entre parasitas de diferentes sexos ou com o hospedeiro. São estudadas preparações de amostras de sincício e vermes inteiros adultos machos e fêmeas por eletroforese bidimensional e frações de baixo peso molecular de sincício de vermes adultos machos e fêmeas por gel-LC. A expressão diferencial de proteínas de sincício investigada por gel-LC foi avaliada por análise estatítica, sendo detectadas 5 proteínas mais abundantes em machos e 2 em fêmeas, além de 6 proteínas identificadas somente em machos e 21 somente em fêmeas. Estas informações de expressão diferencial possibilitam a investigação dos recursos de sobrevivência e reprodução desenvolvidos evolutivamente por estes parasitas. / Schistosomiasis is a neglected tropical disease that affects approximately 200 million people around the world, occurring in America, Africa, the Antilles, Middle East and Near East, besides Southeast Asia. The species found in Brazil is Schistosoma mansoni, the typical treatment being administration of either Praziquantel or Oxamniquine. Although, the infection characteristics of this disease is associated with poor sanitation and hardened socio-economic conditions, resulting in high reinfection rates, which motivates the search for antihelmintic drugs and vaccines that overcome this situation. In this study proteomics techniques are used in the search of proteins potencially involved in the differentiation of individuals of both sexes, in the interactions between them and between the worms and the host. Samples of worm syncytium and adult whole worms of both male and female are studied by two-dimentional electrophoresis, while low molecular weight syncytium proteins from male and female adult worms were investigated by gel-LC. The differential protein expression in the syncytium investigated by gel-LC was analyzed statistically, being detected 5 proteins most abundant in males, and 2 in females, while 6 were identified solely on males and 21 on females. The information concerning protein differential expression allows the investigation of survival strategies developed evolutionarily by these parasites.
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Optimization of Acidic Degradation of Hyaluronic Acid using Design of ExperimentsSandqvist Wedin, Emma January 2019 (has links)
Hyaluronic acid (HA) is an unbranched polysaccharide consisting of the repeating disaccharide unit β(1→4)-GlcA-β(1→3)-GlcNAc and is a naturally occurring biopolymer in bacteria and vertebras. HA is predominantly found in the extracellular matrix (ECM) and the in vivo function of HA can vary depending on molecular weight (Mw) for instance high Mw HA is reported to be anti-angiogenic while low Mw HA induces angiogenesis. HA is a popular component for hydrogels such as dermal fillers. HA is commonly used in dermal fillers. However, other materials, such as other polymers, can be used as well. The project goal was to investigate different degradation processes for production of target Mw HA. Alkaline and acidic degradation processes in combination with increased temperatures seemed as the most promising methods. Degradation tests performed both in aqueous solution as well as heterogeneously in ethanol were evaluated. The acidic degradation in aqueous solution was proven to have the largest degradation constant. Both a robustness test as well as a Design of Experiments (DoE) was performed to investigate the influence different factors had on the degradation speed. The investigated factors were HA concentration, HCl concentration and temperature. Temperature and HCl concentrations proved to be the most influencing factors and a model was developed in the DoE software MODDE to describe how the factors influenced the degradation constant. The model was established as a good significant model with a Q2 value of 0.998 and relative standard deviation (RSD) value of 0.022 after a logarithmic transformation was performed as well as a simplification of the model by excluding some of the factor interactions. The acidic degradation method also proved to be a highly robust method which easily could be used to produce target Mw HA.
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Oxidação de lignina proveniente de resíduos lignocelulósicos agroindustriais para obtenção de compostos químicos aromáticos de maior valor agregado / Oxidation of lignin from agroindustrial lignocellulosic residues to obtain aromatic chemical compounds of added valueOliveira, Fernanda de Carvalho 26 May 2015 (has links)
A exploração de processos viáveis para a conversão da biomassa lignocelulósica em combustíveis limpos e produtos químicos de alto valor agregado, para complementar ou substituir produtos derivados de fontes não renováveis, é crucial para um desenvolvimento sustentável. A valorização e modificação dos componentes lignocelulósicos, torna-se imprescindível para viabilizar o sistema de biorrefinaria. A lignina, macromolécula aromática dominante na natureza, é um destes componentes que, devido a sua estrutura e composição, oferece rotas únicas para a produção de vários químicos de valor agregado. Este trabalho tem como objetivo avaliar o efeito de reações de oxidação em ligninas de bagaço e de palha de cana-de-açúcar, e de casca de café, na obtenção de compostos aromáticos de baixa massa molar, em especial a vanilina, e adicionalmente, verificar a aplicabilidade da lignina oxidada residual na obtenção de matrizes para liberação controlada de herbicida, buscando alternativas para agregar valor à lignina proveniente de resíduos agroindustriais e contribuir com a viabilização de biorrefinarias. Para isso, os materiais lignocelulósicos foram pré-tratados com ácido diluído e submetidos a deslignificação alcalina para obtenção da lignina. As frações obtidas durante cada etapa foram avaliadas quanto a composição química e Espectrometria no Infravermelho (FTIR), e as ligninas obtidas, foram ainda avaliadas por Espectrometria no Ultravioleta (UV) e por Ressonância Magnética Nuclear (1H RMN, 13C RMN e 2D RMN). As ligninas obtidas foram oxidadas em diferentes condições: oxidação enzimática utilizando lacase, em meio ácido e em meio alcalino com H2O2 e oxidação úmida em meio aquoso e alcalino utilizando H2O2. A fração líquida obtida foi analisada por Cromatografia Líquida de Alta Eficiência (CLAE) para identificar e quantificar os aldeídos aromáticos e outros compostos de degradação, enquanto a fração sólida, constituída pela lignina residual oxidada, foi avaliada por FTIR e UV. As ligninas oxidadas provenientes das condições que resultaram em um maior rendimento de vanilina, foram aplicadas na formulação de matrizes para liberação controlada de ametrina. Os resultados mostraram que a lignina de bagaço e de palha de cana não oxidadas são compostas principalmente por unidades siringil e guaiacil, respectivamente, e predominância de ligações ?-O-4, enquanto a lignina de casca de café foi composta principalmente por unidades hidroxil e predominância de ligações C-C, indicando uma estrutura mais condensada. Das oxidações avaliadas, a oxidação em meio alcalino (NaOH 10%) utilizando H2O2 9,1% gerou um maior rendimento de vanilina quando utilizada lignina de bagaço (8,13 mg/g lignina) e de casca de café (1,15 mg/g lignina), e H2O2 6,1% quando utilizada lignina de palha (6,48 mg/g lignina). A aplicação das ligninas oxidadas permitiu a obtenção de matrizes capazes de liberar o herbicida ametrina com diferentes cinéticas, dependendo das propriedades e das proporções das ligninas empregadas. / The exploration of feasible paths for the conversion of the lignocellulosic biomass into clean fuels and high value chemicals, to complement or replace products derived from non-renewable sources, is crucial for a sustainable development. The efficient utilization of the lignocellulosic components is of fundamental importance for the economic viability of biorefineries. Lignin, nature\'s dominant aromatic polymer, is a major component of the biomass that, due to its structuture and chemical composition, is a unique feedstock for producing high-value chemicals. The aim of this study is to seek for alternatives for adding value to lignin from agro-industrial waste in order to contribute to the vialbility of biorefineries. To achieve this, we evaluated the effect of oxidation reactions in sugarcane bagasse and straw lignin, and coffee husk, for obtaining aromatic compounds of low molecular weight, especially vanillin. In addition, the applicability of the residual oxidized lignin for obtaining matrices for the controlled release of herbicides was also examined in this work. For this purpose, the lignocellulosic materials were pretreated with dilute acid and subjected to alkaline delignification to achieve separation of the lignin. The fractions obtained at each stage were analyzed for chemical composition and with Infrared Spectroscopy (FTIR). The lignins were also analyzed using UV-vis Spectroscopy (UV) and Nuclear Magnetic Resonance (1H NMR, 13C NMR and HSQC). The lignins obtained were subjected to oxidation using different physiochemical conditions - enzymatic oxidation with laccase, oxidation in acidic and alkaline medium with H2O2 and wet oxidation in aqueous and alkaline medium using H2O2.The obtained liquid fraction was analyzed by High Performance Liquid Chromatography (HPLC) to identify and quantify the aromatic aldehydes and other compounds of lignin degradation, while the solid fraction, comprising the oxidized residual lignin, was analyzed by FTIR and UV. The oxidized lignins derived from the conditions that have resulted in a maximun yield of vanillin, were applied in the formulation of controlled release matrices of ametryne. Results for non oxidized lignin showed bagasse and straw lignin being composed mainly of syringyl and guaiacil units, respectively, linked predominantly by ?-O-4 bonds, while coffee husk lignin was mainly composed of hydroxyl units linked by C-C bonds predominantly, indicating a more condensed structure. Of all the oxidation reactions, the oxidation in alkaline medium (NaOH 10%) using H2O2 9.1% showed the highest yield of vanillin with bagasse lignin (8.13 mg/g lignin) and coffee husk lignin (1.15 mg/g lignin), and H2O2 6.1% with straw lignin (6.48 mg/g lignin). The application of oxidized lignins as matrices resulted in the release of the herbicide ametryne with different kinetics, depending on the proportions and properties of the lignins applied.
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Oxidação de lignina proveniente de resíduos lignocelulósicos agroindustriais para obtenção de compostos químicos aromáticos de maior valor agregado / Oxidation of lignin from agroindustrial lignocellulosic residues to obtain aromatic chemical compounds of added valueFernanda de Carvalho Oliveira 26 May 2015 (has links)
A exploração de processos viáveis para a conversão da biomassa lignocelulósica em combustíveis limpos e produtos químicos de alto valor agregado, para complementar ou substituir produtos derivados de fontes não renováveis, é crucial para um desenvolvimento sustentável. A valorização e modificação dos componentes lignocelulósicos, torna-se imprescindível para viabilizar o sistema de biorrefinaria. A lignina, macromolécula aromática dominante na natureza, é um destes componentes que, devido a sua estrutura e composição, oferece rotas únicas para a produção de vários químicos de valor agregado. Este trabalho tem como objetivo avaliar o efeito de reações de oxidação em ligninas de bagaço e de palha de cana-de-açúcar, e de casca de café, na obtenção de compostos aromáticos de baixa massa molar, em especial a vanilina, e adicionalmente, verificar a aplicabilidade da lignina oxidada residual na obtenção de matrizes para liberação controlada de herbicida, buscando alternativas para agregar valor à lignina proveniente de resíduos agroindustriais e contribuir com a viabilização de biorrefinarias. Para isso, os materiais lignocelulósicos foram pré-tratados com ácido diluído e submetidos a deslignificação alcalina para obtenção da lignina. As frações obtidas durante cada etapa foram avaliadas quanto a composição química e Espectrometria no Infravermelho (FTIR), e as ligninas obtidas, foram ainda avaliadas por Espectrometria no Ultravioleta (UV) e por Ressonância Magnética Nuclear (1H RMN, 13C RMN e 2D RMN). As ligninas obtidas foram oxidadas em diferentes condições: oxidação enzimática utilizando lacase, em meio ácido e em meio alcalino com H2O2 e oxidação úmida em meio aquoso e alcalino utilizando H2O2. A fração líquida obtida foi analisada por Cromatografia Líquida de Alta Eficiência (CLAE) para identificar e quantificar os aldeídos aromáticos e outros compostos de degradação, enquanto a fração sólida, constituída pela lignina residual oxidada, foi avaliada por FTIR e UV. As ligninas oxidadas provenientes das condições que resultaram em um maior rendimento de vanilina, foram aplicadas na formulação de matrizes para liberação controlada de ametrina. Os resultados mostraram que a lignina de bagaço e de palha de cana não oxidadas são compostas principalmente por unidades siringil e guaiacil, respectivamente, e predominância de ligações ?-O-4, enquanto a lignina de casca de café foi composta principalmente por unidades hidroxil e predominância de ligações C-C, indicando uma estrutura mais condensada. Das oxidações avaliadas, a oxidação em meio alcalino (NaOH 10%) utilizando H2O2 9,1% gerou um maior rendimento de vanilina quando utilizada lignina de bagaço (8,13 mg/g lignina) e de casca de café (1,15 mg/g lignina), e H2O2 6,1% quando utilizada lignina de palha (6,48 mg/g lignina). A aplicação das ligninas oxidadas permitiu a obtenção de matrizes capazes de liberar o herbicida ametrina com diferentes cinéticas, dependendo das propriedades e das proporções das ligninas empregadas. / The exploration of feasible paths for the conversion of the lignocellulosic biomass into clean fuels and high value chemicals, to complement or replace products derived from non-renewable sources, is crucial for a sustainable development. The efficient utilization of the lignocellulosic components is of fundamental importance for the economic viability of biorefineries. Lignin, nature\'s dominant aromatic polymer, is a major component of the biomass that, due to its structuture and chemical composition, is a unique feedstock for producing high-value chemicals. The aim of this study is to seek for alternatives for adding value to lignin from agro-industrial waste in order to contribute to the vialbility of biorefineries. To achieve this, we evaluated the effect of oxidation reactions in sugarcane bagasse and straw lignin, and coffee husk, for obtaining aromatic compounds of low molecular weight, especially vanillin. In addition, the applicability of the residual oxidized lignin for obtaining matrices for the controlled release of herbicides was also examined in this work. For this purpose, the lignocellulosic materials were pretreated with dilute acid and subjected to alkaline delignification to achieve separation of the lignin. The fractions obtained at each stage were analyzed for chemical composition and with Infrared Spectroscopy (FTIR). The lignins were also analyzed using UV-vis Spectroscopy (UV) and Nuclear Magnetic Resonance (1H NMR, 13C NMR and HSQC). The lignins obtained were subjected to oxidation using different physiochemical conditions - enzymatic oxidation with laccase, oxidation in acidic and alkaline medium with H2O2 and wet oxidation in aqueous and alkaline medium using H2O2.The obtained liquid fraction was analyzed by High Performance Liquid Chromatography (HPLC) to identify and quantify the aromatic aldehydes and other compounds of lignin degradation, while the solid fraction, comprising the oxidized residual lignin, was analyzed by FTIR and UV. The oxidized lignins derived from the conditions that have resulted in a maximun yield of vanillin, were applied in the formulation of controlled release matrices of ametryne. Results for non oxidized lignin showed bagasse and straw lignin being composed mainly of syringyl and guaiacil units, respectively, linked predominantly by ?-O-4 bonds, while coffee husk lignin was mainly composed of hydroxyl units linked by C-C bonds predominantly, indicating a more condensed structure. Of all the oxidation reactions, the oxidation in alkaline medium (NaOH 10%) using H2O2 9.1% showed the highest yield of vanillin with bagasse lignin (8.13 mg/g lignin) and coffee husk lignin (1.15 mg/g lignin), and H2O2 6.1% with straw lignin (6.48 mg/g lignin). The application of oxidized lignins as matrices resulted in the release of the herbicide ametryne with different kinetics, depending on the proportions and properties of the lignins applied.
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Efeito da heparina de baixo peso molecular na perda óssea alveolar em ratos Wistar machos : análises morfométrica e histológica / Effects of low molecular weight heparin on alveolar bone loss in wistar rats: Morphometricand histological analysesRivera Oballe, Harry Juan January 2017 (has links)
O objetivo da presente tese foi avaliar os efeitos da heparina de baixo peso molecular (HBPM) na perda óssea alveolar em ratos Wistar. Para a melhor compreensão e entendimento dos efeitos da HBPM se elaborou um único artigo com 40 ratos machos da linhagem Wistar de 60 dias de nascidos, os quais foram dívidos em 4 grupos experimentais previamente randomizados: Grupo Controle (C), Grupos Doença Periodontal (DP), Grupo Heparina (Hp) e Grupo Heparina+Doença Periodontal (Hp+DP) com um período experimental de 60 dias. Um animal foi perdido no período de aclimação, dois animais foram perdidos na primeira de três coletas sanguíneas pré-programadas e um rato foi perdido na colocação da ligadura. Os resultados observados foram analisados são perda óssea alveolar induzida onde houve diferença significava entre os grupos (C) e (DP), entre o grupo (C) e (Hp+DP), entre o grupo (DP) e (Hp) e o grupo (Hp) e (Hp+DP). Foi avaliado perda óssea alveolar não induzida onde não existiu diferença entre os grupos. Foi avaliado o peso do início ao final do período experimental. Foram avaliados o consumo de ração e agua onde não houve diferença significativa entre os grupos. Foram avaliados o número de megacariócitos nos fémures, onde também não existiram diferenças estatísticas. Foram avaliados números de adipócitos no timo, não havendo diferença significativa entre os grupos. Foram avaliados as plaquetas e desvio padrão onde não existiu diferença significativa entre os grupos. Foram avaliados os leucócitos e desvio padrão onde não houve diferença significativa entre os grupos. Posteriormente foi avaliado a porcentagem de linfócitos onde se achou diferença estatisticamente significativa na segunda coleta sanguínea entre o grupo (C) e grupo (Hp+DP) e grupo (Hp) e grupo (Hp+DP). Foi assim que as conclusões deste trabalho foram que o presente estudo mostrou que a HBPM não foi capaz de produzir perda óssea alveolar nos ratos Wistar, mas foi capaz de aumentar a quantidade de leucócitos e linfócitos, indicando a presença de um processo inflamatório. / In order to better understand and understand the effects of (LMWH), a single article was elaborated with 40 male rats of the 60 day old Wistar line, which were divided into four previously randomized experimental groups: Control Group (C), Groups Periodontal Disease (PD), Heparin Group (Hp) and Heparin Group + Periodontal Disease (Hp + PD) with an experimental period of 60 days. One animal was lost in the acclimation period, two animals were lost in the first of three preprogrammed blood collections and one mouse was lost in the ligation placement. The observed results were analyzed for induced alveolar bone loss where there was significant difference between groups (C) and (PD), between group (C) and (Hp + PD), between (PD) and (Hp) group and Group (Hp) and (Hp + PD). Uninduced alveolar bone loss was assessed where there was no difference between the groups. The weight of the onset at the end of the experimental period was evaluated. The ration and water consumption were evaluated where there was no significant difference between the groups. The number of megakaryocytes in the femurs was evaluated, in which there were also no statistical differences. Adipocyte numbers were evaluated in the thymus, with no significant difference between the groups. Platelets and standard deviation were evaluated where there was no significant difference between the groups. Leukocytes and standard deviation were evaluated where there was no significant difference between the groups. Later, the percentage of lymphocytes where a statistically significant difference was found in the second blood collection between group (C) and group (Hp + PD) and group (Hp) and group (Hp + PD) was evaluated. Thus the conclusions of this study were that the present study showed that LMWH was not able to produce alveolar bone loss in Wistar rats, but was able to increase the amount of leukocytes and lymphocytes, indicating the presence of a process inflammatory.
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