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Performance Evaluation and Durability Studies of Adhesive BondsRanade, Shantanu Rajendra 06 October 2014 (has links)
In this dissertation, four test approaches were developed to characterize the adhesion performance and durability of adhesive bonds for specific applications in areas spanning from structural adhesive joints to popular confectionaries such as chewing gum. In the first chapter, a double cantilever beam (DCB) specimen geometry is proposed for combinatorial fracture studies of structural adhesive bonds. This specimen geometry enabled the characterization of fracture energy vs. bondline thickness trends through fewer tests than those required during a conventional "one at a time" characterization approach, potentially offering a significant reduction in characterization times. The second chapter investigates the adhesive fracture resistance and crack path selection in adhesive joints containing patterns of discreet localized weak interfaces created using physical vapor deposition of copper. In a DCB specimen tested under mode-I conditions, fracture energy within the patterned regions scaled according to a simple rule of mixture, while reverse R-curve and R-curve type trends were observed in the regions surrounding weak interface patterns. Under mixed mode conditions such that bonding surface with patterns is subjected to axial tension, fracture energy did not show R-curve type trends while it was observed that a crack could be made to avoid exceptionally weak interfaces when loaded such that bonding surface with defects is subjected to axial compression. In the third chapter, an adaptation of the probe tack test is proposed to characterize the adhesion behavior of gum cuds. This test method allowed the introduction of substrates with well-defined surface energies and topologies to study their effects on gum cud adhesion. This approach and reported insights could potentially be useful in developing chewing gum formulations that facilitate easy removal of improperly discarded gum cuds from adhering surfaces. In the fourth chapter we highlight a procedure to obtain insights into the long-term performance of silicone sealants designed for load-bearing applications such as solar panel support sealants. Using small strain constitutive tests and time-temperature-superposition principle, thermal shift factors were obtained and successfully used to characterize the creep rupture master curves for specific joint configurations, leading to insights into delayed failures corresponding to three years through experiments carried out in one month. / Ph. D.
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Propuesta de instalación de una planta productora de goma de algarroba con fines de exportaciónArbulu Davila, Marcela Sofia January 2024 (has links)
El presente proyecto de investigación tiene como finalidad el diseño de una planta productora de goma de algarroba para su exportación que permita el aprovechamiento de la gran extensión de algarrobos en el Perú, que pueda brindar una opción sostenible en el tiempo y que a la vez traiga mayores beneficios dándole un mayor valor agregado y tenga mayor acogida en el mercado internacional. Para ello, se busca determinar su viabilidad, específicamente, la viabilidad comercial, técnico-tecnológica y económico-financiera. Para ello se realizó un estudio de mercado, en el cual, se evaluaron a los 5 primeros países importadores de goma de algarroba, donde se obtuvo a Alemania como mercado idóneo para satisfacer su demanda. Se busca, además, aprovechar la disponibilidad de algarroba de Lambayeque, obteniéndose a Olmos como localización estratégica para la planta, sobre todo por la cercanía a la materia prima, los bosques secos de Olmos abastecerán a la planta para una producción de 52 417 sacos de goma de algarroba para el primer año. Por último, de acuerdo al análisis económico-financiero para confirmar su viabilidad, se requiere una inversión de $ 3 166 965,49 en total, recuperándose en el año 2 con un VAN de $ 767 402,29 y una TIR de 38,94% confirmando su viabilidad. / The purpose of this research project is to design a carob gum production plant for export, aiming to utilize the vast expanse of carob trees in Peru. The goal is to provide a sustainable option that brings greater benefits by adding more value and gaining wider acceptance in the international market. To achieve this, the project aims to determine its viability, specifically the commercial, technical-technological, and economic-financial viability. A market study was conducted, evaluating the top 5 importing countries of carob gum, identifying Germany as the ideal market to meet its demand. Additionally, the project seeks to take advantage of the availability of carob in Lambayeque, with Olmos being identified as a strategic location for the plant due to its proximity to the raw material. The dry forests of Olmos will supply the plant, enabling a production of 52,417 sacks of carob gum in the first year. Finally, according to the economic-financial analysis to confirm its viability, a total investment of $3,166,965.49 is required, which will be recovered by the second year with a net present value (NPV) of $767,402.29 and an internal rate of return (IRR) of 38.94%, confirming its viability.
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Participative Innovation Platforms (PIP): Guideline for analysis and development of commercial forest product value chains in Sudan and EthiopiaAuch, Eckhard, Alemu Abtew, Asmamaw 22 June 2016 (has links) (PDF)
This working paper was developed with the intention to provide a guideline for participatory analysis and development of commercial forest product value chains, in the context of developing countries. Basically, it was designed for identification and implementation of interventions or upgrading measures for the improvement of commercial forest product (Bamboo, Natural gum and resin, and Gum Arabic) value chains in Ethiopia and Sudan within the framework of a collaborative research project - CHAnces IN Sustainability: promoting natural resource based product chains in East Africa (CHAINS). The PIP instrument could also be applied for other commercial non-timber forest products (NTFPs), by adjusting to the local contexts and environments. It can be an important guide for value chain analysts, especially in the process of designing and verifying upgrading actions through the application of tools like interviewing actors, group discussions, or facilitated workshops.
This working paper particularly provides:
- Background information on basic concepts of value chain analysis and development;
- Review of methodological frameworks for participatory value chain analysis and development;
- Practical details for participatory value chain analysis as implemented by the CHAINS project, including checklists, diagrams, and tools used in the participatory process;
- Critical reflection on the practical application of the approach / Das als Leitfaden gestaltete Arbeitspapier beschreibt Schritt für Schritt das Vorgehen bei der Implementierung von ‚Participative Innovation Platforms‘ (PIP). Das PIP Methodenpaket zur partizipativen Analyse und Entwicklung von Wertschöpfungsketten in Entwicklungsländern wird an Beispielen von kommerziellen Nichtholz-Waldprodukten aus Trockenwäldern Ostafrikas erklärt und gibt praktische Unterstützung zur Durchführung der PIP Workshops mit dem Ziel, Aktivitäten und Interventionen für Innovationen mit Relevanz für die gesamte Wertschöpfungskette gemeinsam mit den beteiligten Akteuren zu vereinbaren.
Das PIP Konzept wurde im Rahmen des entwicklungsorientierten Forschungsprojekts CHAINS (CHAnces IN Sustainability: promoting natural resource based product chains in East Africa) entwickelt, um Bambus -, Weihrauch- und Gummi arabicum Wertschöpfungsketten in Äthiopien und dem Sudan zu verbessern. Das PIP Instrument stellt die Akteure in den Mittelpunkt und kann deshalb sehr flexibel auch für andere Produkte angewendet werden.
Der Leitfaden bietet:
- Hintergrundinformationen zum Konzept von Wertschöpfungsketten;
- Einführung in den methodischen Rahmen für partizipative Analyse und Entwicklung von Wertschöpfungsketten;
- Praktische Anleitung für die partizipative Analyse von Wertschöpfungsketten nach dem im CHAINS Projekt entwickelten Methodenpaket, einschließlich Checklisten, Diagrammen und Methoden;
- Kritische Reflektion zu Möglichkeiten und Grenzen des PIP Methodenpakets.
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Participative Innovation Platforms (PIP): Guideline for analysis and development of commercial forest product value chains in Sudan and Ethiopia: CHAnces IN Sustainability: promoting natural resource based product chains in East Africa (CHAINS) - Working paperAuch, Eckhard, Alemu Abtew, Asmamaw January 2016 (has links)
This working paper was developed with the intention to provide a guideline for participatory analysis and development of commercial forest product value chains, in the context of developing countries. Basically, it was designed for identification and implementation of interventions or upgrading measures for the improvement of commercial forest product (Bamboo, Natural gum and resin, and Gum Arabic) value chains in Ethiopia and Sudan within the framework of a collaborative research project - CHAnces IN Sustainability: promoting natural resource based product chains in East Africa (CHAINS). The PIP instrument could also be applied for other commercial non-timber forest products (NTFPs), by adjusting to the local contexts and environments. It can be an important guide for value chain analysts, especially in the process of designing and verifying upgrading actions through the application of tools like interviewing actors, group discussions, or facilitated workshops.
This working paper particularly provides:
- Background information on basic concepts of value chain analysis and development;
- Review of methodological frameworks for participatory value chain analysis and development;
- Practical details for participatory value chain analysis as implemented by the CHAINS project, including checklists, diagrams, and tools used in the participatory process;
- Critical reflection on the practical application of the approach:1. About the working paper 7
1.1. Purpose 7
1.2. Structure of the working paper 8
2. Introduction 9
2.1. Background: value chains 9
2.2. Background: Participative Innovation Platforms 12
2.3. The context 13
2.4. Overview of the CHAINS project 14
3. Methodological approach of PIP 16
3.1. Ownership and effect 16
3.2. Stages and roles 18
3.3. Diagnostic survey 21
3.3.1. Planning the diagnostic surveys 22
3.3.2. Conducting the diagnostic surveys 24
4. PIP workshops 26
4.1.1. The workshop contents 27
4.1.2. Selection of participants 28
4.1.3. Identification of facilitators 30
4.2. The workshop sessions 32
4.2.1. Schedule of PIP workshop 32
4.2.2. Preparatory session 33
4.2.3. Session 1: Welcome and Introductory 34
4.2.4. Session 2: Vetting of the survey results and detailed VC analysis 35
4.2.5. Session 3: Identification and analysis of critical points 37
4.2.6. Session 4: Identification and analysis of possible solutions 45
4.2.7. Session 5: Development and selection of upgrading strategies 46
4.2.8. Workshop evaluation and documentation 50
5. Limits of the PIP – a critical reflection 50
6. References 52 / Das als Leitfaden gestaltete Arbeitspapier beschreibt Schritt für Schritt das Vorgehen bei der Implementierung von ‚Participative Innovation Platforms‘ (PIP). Das PIP Methodenpaket zur partizipativen Analyse und Entwicklung von Wertschöpfungsketten in Entwicklungsländern wird an Beispielen von kommerziellen Nichtholz-Waldprodukten aus Trockenwäldern Ostafrikas erklärt und gibt praktische Unterstützung zur Durchführung der PIP Workshops mit dem Ziel, Aktivitäten und Interventionen für Innovationen mit Relevanz für die gesamte Wertschöpfungskette gemeinsam mit den beteiligten Akteuren zu vereinbaren.
Das PIP Konzept wurde im Rahmen des entwicklungsorientierten Forschungsprojekts CHAINS (CHAnces IN Sustainability: promoting natural resource based product chains in East Africa) entwickelt, um Bambus -, Weihrauch- und Gummi arabicum Wertschöpfungsketten in Äthiopien und dem Sudan zu verbessern. Das PIP Instrument stellt die Akteure in den Mittelpunkt und kann deshalb sehr flexibel auch für andere Produkte angewendet werden.
Der Leitfaden bietet:
- Hintergrundinformationen zum Konzept von Wertschöpfungsketten;
- Einführung in den methodischen Rahmen für partizipative Analyse und Entwicklung von Wertschöpfungsketten;
- Praktische Anleitung für die partizipative Analyse von Wertschöpfungsketten nach dem im CHAINS Projekt entwickelten Methodenpaket, einschließlich Checklisten, Diagrammen und Methoden;
- Kritische Reflektion zu Möglichkeiten und Grenzen des PIP Methodenpakets.:1. About the working paper 7
1.1. Purpose 7
1.2. Structure of the working paper 8
2. Introduction 9
2.1. Background: value chains 9
2.2. Background: Participative Innovation Platforms 12
2.3. The context 13
2.4. Overview of the CHAINS project 14
3. Methodological approach of PIP 16
3.1. Ownership and effect 16
3.2. Stages and roles 18
3.3. Diagnostic survey 21
3.3.1. Planning the diagnostic surveys 22
3.3.2. Conducting the diagnostic surveys 24
4. PIP workshops 26
4.1.1. The workshop contents 27
4.1.2. Selection of participants 28
4.1.3. Identification of facilitators 30
4.2. The workshop sessions 32
4.2.1. Schedule of PIP workshop 32
4.2.2. Preparatory session 33
4.2.3. Session 1: Welcome and Introductory 34
4.2.4. Session 2: Vetting of the survey results and detailed VC analysis 35
4.2.5. Session 3: Identification and analysis of critical points 37
4.2.6. Session 4: Identification and analysis of possible solutions 45
4.2.7. Session 5: Development and selection of upgrading strategies 46
4.2.8. Workshop evaluation and documentation 50
5. Limits of the PIP – a critical reflection 50
6. References 52
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Etude des mécanismes de structuration d’assemblages β-lactoglobuline-gomme d’Acacia en présence d’un flavonoïde, la quercétine / Structuration mechanism study of protein-polysaccharide assemblies in presence of flavonoid, quercetinAberkane, Leïla 08 October 2010 (has links)
Les flavonoïdes sont des ingrédients prometteurs pour différentes applications alimentaires et non alimentaires, grâce à leurs propriétés antioxydantes et biologiques. Cependant, la formulation de ces molécules est difficile à réaliser en raison de leur faible solubilité dans la plupart des solvants. Afin de remédier à cette difficulté, l’approche suivie dans cette étude est l’incorporation des flavonoïdes dans des particules à base de biopolymères (protéine-polysaccharide), stables et fonctionnelles. Le principal objectif de cette thèse était d’acquérir des connaissances à différentes échelles d’étude sur les mécanismes d’interaction et d’assemblage entre un flavonoïde, la quercétine, et deux biopolymères,B-lactoglobuline (BLG) et la gomme d’Acacia (AG). Dans une première étape, nous avons pu mettre au point des particules submicroniques (Dh : ~250 nm) de gomme d’Acacia-quercétine (GAQ) possédant une structure assimilée à un assemblage « cœur-couronne » et traduisant un comportement correspondant à celui de particules molles. Dans une seconde étape, nous avons étudié les mécanismes d’assemblage des particules de GAQ avec la BLG à pH 4,2 et à 25 °C. Les paramètres thermodynamiques d’interaction ont été déterminés par calorimétrie de titration isotherme (ITC) et montrent des isothermes de liaison caractérisées par une séquence exothermique-endothermique. Les différentes entités structurales formées durant la complexation entre la GA et la BLG ou la GAQ et la BLG ont été caractérisées en utilisant la même approche par titration que pour l’ITC. Enfin, des mesures par spectroscopie infra-rouge à transformée de Fourier (FTIR) ont montré une modification de la structure secondaire de la BLG après interaction avec la GA et la GAQ. D’importantes pertes de structures (hélices-α et feuillets-β), encore plus marquées en présence de quercétine / Flavonoids are promising ingredients in food and non food applications through their antioxidative and biological properties. However, their negligible solubility in most solvent renders problematic technological developments. In order to overcome this drawback, the approach followed in this study was the incorporation of flavonoids in stable and functional particles based on biopolymers (protein-polysaccharide). The main objective of this thesis was to acquire knowledge at different scales to study the mechanisms of interaction and linkage between a flavonoid, quercetin, and two biopolymers, B-lactoglobulin (BLG) and Acacia gum (AG). In a first step, we were able to develop submicronic particles (Dh : ~250 nm) of quercetin-Acacia gum (GAQ) based on a core of quercetin and a shell of Acacia gum, reflecting a behavior of soft particles. In a second step, we investigated the assembly mechanisms GAQ with BLG at pH 4.2 and 25 ° C. The thermodynamic parameters of interaction were determined by isothermal titration calorimetry (ITC) and show binding isotherm characterized by an exothermic-endothermic sequence. The various structural entities formed during the complexation between GA and BLG or BLG and GAQ were characterized using the same approach as for the ITC titration. Finally, measurements using infra-red Fourier transform (FTIR) showed changes in the secondary structure of BLG after interaction with the GA and the GAQ. There was a significant loss of secondary structures (α-helices and β-sheets), even more pronounced in presence of quercetin
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Etude du mécanisme de coacervation complexe entre les fractions principales de la gomme d'Acacia et la [beta]-lactoglobuline - Comparaison avec la gomme d'Acacia non fractionnée / Study of the mechanism of complex coacervation between beta-lactoglobulin and the major fractions of acacia gum - comparaison with the unfractionnated acacia gumAkil, Suzanna 19 April 2007 (has links)
La coacervation complexe, une séparation de phase associative principalement induite par des interactions électrostatiques, entre la B-lactoglobuline (BLG, protéine animale) et la gomme d’Acacia (AG, polysaccharide végétal) a été étudiée dans ce travail. La plus grande difficulté pour comprendre la coacervation complexe au niveau moléculaire entre BLG et AG révèle être la polymolécularité élevée d’AG. A partir de là, la motivation principale de cette thèse était de comprendre et contrôler les interactions entre la BLG et les fractions moléculaires d’AG, FI (~88% d’AG) et FII (~10% d’AG) en utilisant la titration calorimétrique isotherme, la diffusion statique et dynamique de lumière, la mobilité électrophorétique, la Granulo-Polarimétrie et la microscopie optique. Une énergie d’interaction plus forte, une stoechiométrie d’association plus faible et ainsi une complexation favorable ont étés montrées entre la BLG et FII en relation avec l’accessibilité et la densité de charges plus élevées de FII. Les résultats majeurs de cette étude ont ainsi montré des rôles différents des fractions de l’AG dans la coacervation complexe avec la BLG / The complex coacervation mechanism, an associative phase separation mainly induced by electrostatic interactions, between ?-lactoglobulin (BLG, animal protein) and Acacia gum (AG, vegetal polysaccharide) was studied in this work. The most significant difficulty to understand complex coacervation between BLG and AG at the molecular level is the molecular weight polydispersity of AG. From there, the main motivation of this research was to better understand and control the interactions between BLG and the major molecular fractions of AG, FI (~88% of AG) and FII (~10% of AG) using isothermal titration calorimetry, static and dynamic light scattering, electrophoretic mobility, Granulo-Polarimetry and optical microscopy. Higher energy of interaction, lower stoichiometry of association and then favorable complexation were shown between BLG and FII in relation with higher accessibility and density of charges for FII. The major results of this study reveal then different roles of AG fractions in complex coacervation with BLG
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L'influence des cultivars sur les proprietés fonctionnelles de la caroube Libanaise / The influence of cultivar on functional properties of the lebanese carobHaddarah, Amira 12 December 2013 (has links)
Le caroubier est considéré comme l'un des arbres fruitiers et forestiers qui présente le plus grand potentiel de valorisation puisque toutes les parties de cette plante sont utilisables dans plusieurs applications industriels. Le caroubier est cultivé dans plusieurs régions du Liban mais peu d'études sont disponibles sur les voies de valorisation et sur les propriétés fonctionnelles et structurales des graines et des gousses. Ainsi, dans le cadre d'une démarche qui vise à promouvoir et contribuer à une meilleure valorisation et gestion de cette ressource renouvelable, nous avons entrepris dans cette thèse des travaux consacrés à la caractérisation et à l'évaluation de la valeur nutritive et fonctionnelle des gousses de caroube issues de plusieurs régions libanaise. Ces travaux ont porté notamment sur la caractérisation morphologique et physico-chimique des gousses et sur la purification des gommes extraits des graines. Ces gommes ont fait l'objet d'une étude approfondie portant sur leur comportement rhéologique et la relation entre ce comportement, la variété et le lieu géographique. Nous avons aussi déterminé les isothermes de sorption de ces gommes pour prédire les conditions idéales de leur conservation. Les résultats obtenus à l'issue de cette étude ont démontré clairement la présence des corrélations morphologie, composition chimique et coordonnées géographiques de différents cultivars étudiés. De même, les études structurales et rhéologiques ont montré des différences significatives entre les gommes purifiées. Cette différence semble être liée à une variation du rapport galactose/mannose et de la masse molaire observée selon les variétés. Par ailleurs, les études des isothermes de sorption ont permis de fournir des informations complémentaires sur leurs hygroscopicités et par conséquence sur les conditions idéales de leur conservation / The carob plant is considered as one of the fruit and forester tree that has the greatest potential of valorization since all the parts of this plant can be used in several food and cosmetic applications. The carob is cultivated in several areas of lebanon but few studies are available on the ways of valorization and the functional and structural properties of the different fractions of this tree (seeds and pods). Thus, in view to develop a strategy aims to promote and contribute to a better valorization and management of this renewable resource, we undertook in this thesis of work devoted to the characterization and the evaluation of nutritive and functional properties of the carob pods resulting from several lebanese areas. This work focused particularly on the morphological and physicochemical characterization of the pods and the purified fraction of gum. These gums were the subject of a thorough study relating to their rheological behavior and the relation between this behavior, the variety and the geographical localization of the studied varieties. We also determined the isotherms of sorption of these gums to predict the ideal conditions of their conservation. The obtained results clearly showed the presence of the correlations between morphology, chemical composition and geographical localization of the different studied cultivars. In the same way, the structural and rheological studies showed significant differences between purified gums. This difference seems to be related to a variation of the galactose /mannose ratio and molar mass according to the varieties. These interesting rheological properties open the carob gums a new niches of valorization with added values. In addition, the studies of the isotherms of sorption provided additional information on their hygroscopicities and by consequence on the ideal conditions of their conservation
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Complexos híbridos de polieletrólitos e magnetita para liberação controlada de amoxicilina / Hybrid complexes of polyelectrolytes and magnetite for controlled release of AmoxicillinBueno, Pedro Vinicius de Assis 10 August 2018 (has links)
Novos sistemas biocompatíveis para aplicações biotecnológicas são relevantes não só do ponto de vista tecnológico, mas também para avanços científicos. A presente dissertação visou à criação e caracterização de filmes finos (espessura de até 100 nm) ou micrométricos (espessura de 50 µm a 100 µm) formados por goma xantana (GXT), poli(cloreto de dimetil dialil amônio), (PDDA), albumina bovina sérica (BSA), e nanopartículas de magnetita (NPM). A incorporação de amoxicilina (Amox), um antibiótico amplamente utilizado contra muitas infecções, nos filmes foi realizada durante a formação dos sistemas. Os filmes finos foram caracterizados através de elipsometria e microscopia de força atômica. Em solução, as interações favoráveis entre o Amox e a BSA foram evidenciadas por mudanças substanciais na estrutura secundária da BSA, como revelado pelo dicroísmo circular. Os filmes micrométricos (patches) de GXT e GXT/NPM/BSA foram imersos em Amox 2 g/L, levando a incorporação de 10 ± 3 e 17 ± 4 µg/cm³ de Amox, respectivamente. Sua caracterização compreendeu espectroscopia vibracional no infravermelho por transformada de Fourier no modo de refletância total atenuada (FTIR-ATR), microscopia eletrônica de varredura (MEV), medidas de sorção e espectrometria de emissão óptica com plasma indutivamente acoplado (ICP-OES). A incorporação de 0,2% em massa de Fe3O4 nos \"patches\" e sua exposição a um campo magnético externo, viabilizou a liberação total in vitro de Amox, em pH 5,5 e em 0,02 mol/L de NaCl, seguindo o comportamento quasi-Fickiano. A difusão da Amox dos \"patches\" de GXT/NPM/BSA em ágar contendo Staphylococcus aureus e Escherichia coli, levou halos de inibição consideráveis. A inibição do crescimento de E. coli foi particularmente eficiente sob efeito de campo magnético externo. / New biocompatible systems for biotech applications are relevant not only from a technological point of view, but also for scientific advances. The present project aimed at the creation and characterization of thin films (thickness up to 100 nm) or micrometric patches (thickness of 50 µm to 100 µm) formed by the deposition of xanthan gum (GXT), poly (dimethyl diallyl ammonium chloride) (PDDA), bovine serum albumin (BSA), and magnetite nanoparticles (NPM). The incorporation of amoxicillin (Amox), a widely used antibiotic against many infections, in the films was performed during the formation of the systems. Thin films were characterized by means of ellipsometry and atomic force microscopy. In solution, favorable interactions between Amox and BSA were evidenced by substantial changes in the secondary structure of BSA, as revealed by circular dichroism spectra. Patches of GXT and GXT/NPM/BSA were immersed into Amox solution at 2 g/L, leading to the Amox incorporation of 10 ± 3 and 17 ± 4 µg/cm3, respectively. The patches characterization included Fourier Transform Infrared vibration spectroscopy in the attenuated total reflectance mode (FTIR-ATR), scanning electron microscopy (MEV), sorption measurements and inductively coupled plasma optical emission spectrometry (ICP-OES). The incorporation of 0.2 wt% of Fe3O4 in the patches and their exposure to an external magnetic field, allowed the total in vitro release of Amox, at pH 5.5 and 0.02 mol/L NaCl, following the behavior quasi-Fickian. Amox diffusion from GXT/NPM/BSA patches in agar containing Staphylococcus aureus and Escherichia coli led to a considerable zone of inhibition. Inhibition of E. coli growth was particularly efficient under the effect of external magnetic field.
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Efeito in situ de uma goma de mascar contendo caseína fosfopeptídea - fosfato de cálcio amorfo (CPP-ACP) na erosão dentária / In situ effect of chewing gum containing casein phosphopeptide - amorphous calcium phosphate on dental erosionAlencar, Catarina Ribeiro Barros de 29 May 2013 (has links)
O presente trabalho avaliou o efeito in situ de uma goma de mascar comercialmente disponível contendo caseína fosfopeptídea - fosfato de cálcio amorfo (CPP-ACP) na erosão dentária. Para a primeira etapa do estudo (capacidade remineralizadora) utilizaram-se 72 blocos de esmalte humano selecionados pela dureza de superfície (SHi) e erodidos in vitro pela imersão em Coca Cola®, pH 2,4 por 3 min (avaliação da dureza - SHd). Os blocos foram randomizados entre os grupos: GI Trident Fresh® (sem CPP-ACP), GII controle (sem chiclete) e GIII Trident Total® (com CPPACP). Doze voluntários utilizaram dispositivos intrabucais palatinos por 24 h em 3 fases cruzadas. Nas fases de GI e GIII os voluntários mascaram um chiclete (30 min) e em todas as fases após 2h, a dureza foi avaliada (SHf1). Os blocos foram reposicionados e os dispositivos usados por mais 22 h (+ 3 ciclos de mastigação de chiclete - GI e GIII). A dureza foi reavaliada (SHf2) para cálculo do percentual de recuperação de dureza (%SHR) após 2 e 24h. Na segunda etapa do estudo (ciclagem erosiva) 48 blocos de esmalte humano hígidos foram aleatorizados entre os grupos (GI, GII e GIII) e 8 voluntários utilizaram dispositivos intrabucais palatinos em fases cruzadas de 7 dias cada (washout de 7 dias). O protocolo de ciclagem erosiva foi de 4 imersões diárias do dispositivo intrabucal em 150 ml de Coca Cola® durante 5 min. Nos grupos I e III após cada desafio erosivo e reinserção do dispositivo na cavidade bucal, os voluntários mascaram um chiclete durante 30 min. A alteração da superfície do esmalte foi mensurada por perfilometria (μm). Os dados foram submetidos à ANOVA (2 critérios - etapa 1; 1 critério - etapa 2) e teste Tukey (α=0,05). Os resultados da recuperação de dureza demonstraram haver diferença significativa entre os grupos e os tempos (p<0,05). O Trident Total® (2h = 50,0%; 24h = 95,9%) promoveu maior recuperação de dureza que o Trident Fresh® (2h= 30,0%; 24h= 71,1%) e o grupo controle (2h = 15,7%; 24h = 40,9%). No desafio erosivo prolongado, o Trident Total® (5,2± 2,8 μm) e o Trident Fresh® (3,8 ± 1,5 μm) reduziram significativamente o desgaste dentário em relação ao grupo controle (6,8 ± 3,5 μm), no entanto, não houve diferença significativa entre os chicletes (p>0,05). Conclui-se que o efeito remineralizador da saliva foi maior após utilização de goma de mascar, sendo significativamente aumentado em função do período de remineralização e pela presença de CPP-ACP na goma de mascar. Contudo, para o protocolo de desafio erosivo adotado, apesar da goma de mascar convencional apresentar efeito na inibição do desgaste erosivo, o comportamento da goma de mascar com incorporação de CPP-ACP foi similar. / This study evaluated the in situ effect of a commercial chewing gum containing casein phosphopeptide - amorphous calcium phosphate (CPP-ACP) on dental erosion. On the first stage (remineralizing effect) 72 human enamel blocks, which were selected by surface hardness (SHi) and eroded in vitro by immersion in cola drink, pH 2,4 for 3 minutes (hardness evaluation - SHd) were used. Blocks were randomized into 3 groups: GI Trident Fresh® (conventional gum, without CPP-ACP), GII control (no gum) and GIII Trident Total® (with CPP-ACP). Twelve volunteers wore intraoral palatal devices for 24 h in 3 crossover phases. In phases of GI and GIII volunteers chewed a gum (30 min) and in all phases after 2h, the surface hardness was evaluated (SHf1). The blocks were reinserted and the devices used for additional 22h (+ 3 cycles of chewing gum - GI e GIII). The surface hardness was reassessed (SHf2) to calculate the percentage of surface hardness recovery (%SHR) after 2 and 24h. In the second stage (erosive cycling) 48 healthy human enamel blocks were randomized between groups (GI, GII and GIII) and 8 volunteers wore intraoral palatal devices in crossover phases of 7 days each (washout of 7 days). The cycling protocol consisted of 4 daily immersions of the intraoral device into 150 ml of cola drink for 5 min. In groups I and III after each erosive challenge and oral device reinsertion into oral cavity, the volunteers chewed a gum for 30 min. The enamel surface alterations were measured by profilometry (μm). Data were analyzed by Anova (Two way - stage 1, One way - stage 2) and Turkeys test (α=0,05). The results of percentage of surface hardness recovery showed significant differences for factors groups and time (p<0.05). Trident Total® (2h = 50.0%; 24h = 95.9%) showed higher percentage of surface hardness recovery than the Trident Fresh® (2h = 30.0%; 24h = 71.1%) and control group (2h = 15.7% 24h = 40.9%). In the prolonged erosive challenge, Trident Total® (5.2 ± 2.8 μm) and Trident Fresh® (3.8 ± 1.5 µm) significantly reduced tooth wear compared to control group (6.8 ± 3, 5 µm). However, there was no significant difference between chewing gums. It is concluded that the saliva remineralizing effect increased after the use of conventional chewing gum and was enhanced by prolonged period of remineralization and by the presence of CPPACP in the chewing gum. However for the adopted erosive challenge, despite the conventional chewing gum being able to diminish erosive wear, the chewing gum containing CPP-ACP showed similar effect.
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Análise da cadeia produtiva e estrutura de custos do setor brasileiro de produtos resinosos. / Productivity chain analysis and cost structure of the Brazilian naval stores products.Ferreira, José Pinto da Rocha Jorge 04 February 2002 (has links)
Este trabalho iniciou-se com a descrição da goma-resina, do breu e da terebintina. A primeira, extraída de plantios de Pinus elliotti e Pinus caribaea através da resinagem, é a matéria prima base da cadeia dos produtos resinosos. O breu e a terebintina, obtidos através do processamento da goma-resina, são seus primeiros derivados e são, por sua vez, matéria-prima de diversas indústrias químicas, como a de tintas, vernizes, colas, borrachas, desinfetantes, perfumaria, e outras. Passaram-se também em revisão os vários aspectos técnicos das operações de resinagem e, ainda, o processamento de resina. Igualmente se analisou a estrutura dos custos de produção, foram mensurados os custos específicos da operação de resinagem e, de forma menos aprofundada, os da operação de processamento de resina. Procedeu-se também à análise da cadeia produtiva, descrevendo o surgimento e a evolução do setor dos produtos resinosos brasileiro, a sua distribuição e concentração, sob a ótica da Economia dos Custos de Transação (ECT). A metodologia adotada neste trabalho baseou-se na análise gráfica e tabular de dados secundários e da pesquisa de campo realizada por intermédio de questionários, elaborados e lançados em articulação com a ARESB (Associação dos Resinadores do Brasil), e, ainda, de entrevistas com diversos empresários e representantes do setor. A produção brasileira satisfaz o consumo do país e ainda origina excedentes que são exportados e proporciona saldos comerciais positivos. O mercado internacional é dominado pela China que, com vastos recursos florestais e muita mão-de-obra disponível, responde por cerca de 65% da produção mundial e dita os preços dos produtos resinosos. A estrutura dos custos de produção da operação de resinagem, considerada um aspecto importante para a visualização dos problemas internos do setor, indica, sobretudo, uma importante participação do fator mão-de-obra, mas não se constataram níveis críticos relacionados aos seus custos como sucede atualmente em outros países produtores de resina. O setor, englobando empresas de resinagem e de processamento de resina, surgiu de esforços de grandes empresas das indústrias químicas e florestais, ainda hoje tem como agentes empresas provenientes de etapas a montante e a jusante na cadeia, e empresas estrangeiras que viram no Brasil a oportunidade de continuar ligadas a atividade. A produção está sobretudo localizada no Estado de São Paulo e o mercado, ao contrário do que se pressupunha, não se encontra concentrado em algumas empresas. Observando os parâmetros de ECT utilizados na análise da cadeia produtiva, a forma híbrida das estruturas de governança parece ser a predominante no setor. À semelhança de uma cadeia agro-industrial normal, o setor apresenta estrutura de governança voltada para o mercado nos estágios iniciais da cadeia, tendendo ao longo da cadeia, no sentido jusante, para situações hierarquizadas. Verifica-se uma tendência de verticalização das empresas de processamento de resina e derivados para montante como forma de garantir suas matérias primas. / This paper is initiated with the description of gum resin, gum rosin and turpentine. Gum resin, mainly extracted from Pinus elliottii and Pinus caribaea plantations, is the basic raw material in the production chain. Gum rosin and turpentine are the first two products obtained after processing the pine gum, and are themselves used as raw material in the chemical industry to produce paints, varnishes, glues, rubber, perfumes, disinfectants, and others. The gum resin extraction and the technical aspects of its processing are revised. Tapping, industrialization and the whole production cost structure are also analyzed. The origin and evolution of the industry is analyzed, as well as its distribution and concentration, and the production chain is described from a Transaction Cost Economy (TCE) point of view. The methodology adopted in this study is based on graphical and tabular analysis of secondary data, interviews with industry owners and managers, and information collected from questionnaires jointly designed with the Brazilian Gum Resin Producers Association (ARESB). Brazilian production covers domestic demand, and the surplus generated is exported. The international market is controlled by China, which with large forest and labor resources accounts for approximately 65% of the world production and establishes prices. Labor is the main item in the extraction costs structure, but is not as problematic as in other producing countries. The gum rosin and turpentine production segment, initially developed in Brazil by large forest and chemical companies, is still led today by groups positioned upstream and downstream in the production chain, and by foreign enterprises that have seen in Brazil the opportunity to maintain their link with the activity. Production is mainly located in the State of São Paulo, and the market, contrarily to what was expected, does not concentrates in a few companies. According to the TCE parameters used in the production chain analysis, a hybrid governing structure comes up as the predominant structure in this segment. Similarly to a common agribusiness, the chains initial stages are market orientated, but towards the end of the chain the segment shows a more hierarchical structure. A trend to verticalization upstream is also noted on gum rosin and turpentine producers, in order to guarantee adequate stocks of raw material.
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