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Copyright of Acta Odontologica Latinoamericana: AOL is the property of Acta Odontologica Latinoamericana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Professional Business Review (JPBReview) is the property of Open Access Publications LLC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study aims to study the photodegradation process of methylene blue using a synthetic chitosan-Fe2O3 composite and their characterization. Based on the characterization material synthetic, chitosan-Fe2O3 (1:1) composite showed the best material with the smallest crystal size (1.13 nm), the surface morphology was lumpy and had an uneven shape with the composition of the constituent (Carbon (C) 42.88%, Oxygen (O) 48.68%, and Iron (Fe) 29.90%), and showed the smallest energy band gap (1.41 eV) which led us to conclude that the formation of the chitosan-Fe2O3 composite can reduce the energy band gap of Fe2O3. The best composite material then was used to evaluate the activity in degrading methylene blue. The optimum condition in degrading was reached at a contact time of 180 min and pH 9 with a percentage decrease in methylene blue concentration of 90.00%. The effect of concentration variations occurred at 5 ppm with a decrease of 89.62%. Total organic carbon analysis showed that the decrease in methylene blue concentration reached 92.20%. Based on that, it is concluded that the chitosan-Fe2O3 composite could be a potential alternative material to degrade methylene blue. [ABSTRACT FROM AUTHOR]

This research proposes the production of a composite material consisting of nanosheets of graphitic carbon nitride (g-CN) coated with cobalt ferrite nanoparticles (CF) and embedded in crosslinked chitosan. The aim of the work was to apply this material in photocatalytic inactivation processes of water bodies polluted with bacteria, as well as in the oxidative degradation of ibuprofen, using a 400 nm and 10 W radiation source. The g-CN was obtained through the thermal decomposition of melamine or urea, and CF was produced from FeCl2.4H2O and Co(NO3)2.6H2O in an alkaline medium in the presence of g-CN nanosheets. The resulting material was dispersed in an acetic chitosan solution, forming beads by dripping the mixture onto 2M NaOH solution. The synthesized materials were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Field Emission Scanning Electron Microscopy (FESEM). The final composite (chitosan/1CF5g-CN_m) achieved a yield close to 51% for the oxidative photocatalytic degradation efficiency of ibuprofen in aqueous solution. Regarding bacterial inactivation tests of Escherichia coli, a reduction of up to two orders of magnitude, corresponding to 21% at the end of the photocatalytic process, was attained. [ABSTRACT FROM AUTHOR]

Em busca de encontrar alternativas que permitam diminuir o uso indevido de polímeros derivados de hidrocarbonetos e seus efeitos colaterais com o meio ambiente. O objetivo da seguinte revisão bibliográfica sistemática foi comparar o comportamento mecânico à tração de filmes feitos com quitosana, amido de batata e hidroxipropilmetilcelulose (HPMC), utilizados para a embalagem de produtos alimentícios, comparando sua tensão de tração, módulo de elasticidade e deformação à ruptura. A busca foi realizada no SCOPUS, Science Direct, Scielo a nível nacional (Colômbia) e repositórios da Universidad Nacional Abierta y Distancia (UNAD) e Universidad Nacional de Colombia (UNAL) durante 2013-2022, implementando diferentes equações de busca. A partir do estudo bibliográfico, foi analisado que a HPMC apresenta as melhores propriedades mecânicas de tração (tensão de tração: 32,44MPa; deformação à ruptura: 17,37%; módulo de elasticidade: 305MPa), seguida de perto pela quitosana (tensão de tração: 32,01 MPa; deformação à ruptura: 15,5%; módulo de elasticidade: 303,5 MPa) e, finalmente, amido de batata (tensão de tração: 10,56 MPa; deformação à ruptura: 11,89%; módulo de elasticidade: 395 MPa). Espera-se que esta revisão de literatura promova o desenvolvimento e aplicação de filmes à base de polissacarídeos para embalagens de alimentos pela indústria como uma estratégia para resolver problemas ambientais e para suas propriedades mecânicas ótimas.

La producción en Cuba de ajo (Allium sativum L.) es baja a pesar de que en este cultivo se consume una gran cantidad de fertilizantes químicos. Dentro de los bioestimulantes de producción nacional, con resultados beneficiosos en el crecimiento, rendimiento y la protección antiestrés en diferentes cultivos, se encuentra el QuitoMax®. De esta forma el objetivo de este trabajo fue evaluar el efecto de la aplicación de diferentes dosis de QuitoMax® en el crecimiento y desarrollo del cultivo de ajo clon ‘Criollo Víctor’ en condiciones de campo. Previo a la plantación manual en canteros, la “semilla” se desgranó y se realizó la inmersión de las mismas en diferentes concentraciones de QuitoMax® (1; 5 y 10 mg L-1) y a los 50 días después de plantado (ddp) se realizó una aplicación foliar con estas mismas concentraciones, se empleó un diseño experimental de bloques al azar con cuatro tratamientos y tres réplicas. Se evaluaron los indicadores altura de la planta, número de hojas y contenido de clorofilas a los 70; 90 y 110 ddp. A los 120 ddp se determinaron los diámetros del cuello y ecuatorial del bulbo, número de bulbillos, masa fresca y seca del bulbo, así como el calibre, firmeza y el rendimiento. La mayoría de los indicadores evaluados se incrementaron con el uso del bioestimulante, la dosis más promisoria de QuitoMax® resultó ser la de 10 mg L−1. Este bioestimulante presenta potencialidades para insertarse en el sistema de producción del ajo.

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of local intra-articular injection therapy for the treatment of osteoarthritis has experienced an increase in recent decades. With this treatment, frequent injections are necessary to obtain an adequate anti-inflammatory effect, which implies greater inconveniences for the patients. An alternative could be use injectable controlled release systems that allow to reduce the frequency of application. The aim of this research is to develop a system based on dexamethasone-loaded polycaprolactone particles dispersed in a thermosensitive chitosan/Pluronic® F-127 hydrogel. The microparticles were obtained by the double emulsion / solvent evaporation technique. The hydrogel is prepared from a physical mixture of chitosan and Pluronic® F127. The microparticle / hydrogel system was prepared by dispersing 50 mg of particles in 2 mL of the liquid hydrogel. The samples were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The cytocompatibility of the samples was evaluated using the C-28 cell line of human chondrocytes by the 3- (4,5-dimethylthiazol-2-yl) -5- (3-carboxymethoxyphenyl) -2- (4-sulfophenyl) -2H-tetrazolium (MTS) assay and a study of dexamethasone release in phosphate buffered saline solution (PBS) was carried out for 7 days. The particles have a defined spherical shape and a size between 4-14 µm. The characterization by Fourier transform infrared spectroscopy showed that there are no chemical interactions between chitosan and Pluronic® F127 in the hydrogel. All the analyzed samples were cytocompatible with the C-28 cell line. The release study showed that the system has greater control over dexamethasone release. The system proves to be a promising option as an intra-articular administration system in the pharmacological treatment of osteoarthritis. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Investigaciones Agroindustriales is the property of Revista Colombiana de Investigaciones Agroindustriales del Centro Agropecuario Sena Buga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Odontologica Latinoamericana: AOL is the property of Acta Odontologica Latinoamericana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study reports the optimization of the preparation of etoricoxib (ETX)-loaded low molecular weight of chitosan (LMWC) nanoparticles (ETX-LMWC-NPs) by ionic gelation method with sodium tripolyphosphate (TPP) as cross-linking agent. The independent variables (LMWC/TPP mass ratio, LMWC, and poloxamer 188 concentration) were formulated and optimized using response surface methodology (RSM) Box-Behnken design (BBD) with three levels for each factor. Size of particles, polydispersity index (PDI), and encapsulation efficiency was investigated as the dependent variable. ETX-LMWC-NPs were characterized by particle size analyzer, scanning electron microscope, UV-Vis spectrophotometry, and Fourier transforms infrared spectroscopy. The ETX-LMWC-NPs have an average particle size of 259.91 nm, a PDI of 0.041, and encapsulation efficiency of 51.25%. ETX-LMWC-NPs are spherical and have a spectrum at wavenumber 1656 cm-1 and 718 cm-1, respectively, indicating the presence of C=N and C-Cl originating from the ETX compound. The ETX release profile at pH 1.2 and 6.8 mediums approach the Korsmeyer-Peppas model. ETX released pH 1.2 did not differ significantly from free ETX with a maximum 10-12% release. ETX release at pH 6.8 had a maximum release of 21% and showed a 19% increase in dissolution rate than free ETX. The ETX-LMWC-CSNPs prepared by optimum formula (2.65 % LMWC, 5.5 LMWC/TPP mass ratio, and 1 mg/mL) showed stable monodispersity nanoparticles and easily soluble in water. [ABSTRACT FROM AUTHOR]

Copyright of Dental Press Endodontics is the property of Dental Press International and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work was carried out with the objective of documenting the main biostimulants used in the world to mitigate the effects of water stress, as well as the physiological, morphological and biochemical effect that these substances cause in the crops that have been studied. A review of scientific articles published in national and international journals, as well as master's and doctoral theses from different universities and scientific centers was carried out. The application of biostimulants is one of the most promising agricultural practices to mitigate the effects of drought on plants. There are numerous microorganisms in the world, as well as synthetic or naturally occurring substances that have a positive effect on crop development, yields and drought tolerance. They can optimize biochemical, physiological and anatomical processes such as regulating stomatal conductance, increasing the concentration of proline and cellular osmolytes, increasing photosynthetic efficiency, inducing the production of LEA proteins and antioxidant enzymes, reducing cell membrane damage, maintaining leaf water content and increasing the soil exploration capacity of the root system. [ABSTRACT FROM AUTHOR]

Paraquat is an herbicide that has been widely used in pineapple, cotton, rice, banana, potato, coffee, sugarcane, among others, since the 1960s, as it is low cost, highly effective and not cumulative to the ground. However, from the 1980s onwards, several cases of poisoning related to this agrochemical were observed and the herbicide ended up becoming very well known for its high toxicity. Thus, aiming to reduce the exposure and avoid the toxic effects of this herbicide, the objective of this study was to promote the anchoring of Paraquat in polymeric chitosan nanoparticles and to evaluate the behavior for its controlled release. The anchoring potential and controlled release of paraquat from the biopolymer were evaluated using conductimetric titration with a standardized NaOH solution and spectroscopy in the UV-vis region. The results obtained showed the efficiency of chitosan nanoparticles in the controlled release process of the anchored herbicide. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

RESUMO A engenharia de tecidos caracteriza-se como ciência interdisciplinar, a qual vem desenvolvendo biomateriais para a regeneração do tecido ósseo no âmbito das medicinas humana e veterinária. O objetivo desta pesquisa foi avaliar a regeneração óssea obtida da aplicação do hidrogel de quitosana associado ao glicerol fosfato em falha óssea experimentalmente induzida no rádio de coelhos. Foram utilizados 15 coelhos adultos, distribuídos aleatoriamente em dois grupos, representados por cada um dos rádios de cada animal, sendo um grupo tratado com hidrogel de quitosana associado ao glicerol fosfato (grupo biomaterial - GB) e um grupo que não recebeu tratamento com o biomaterial (grupo controle - GC). Os animais foram avaliados radiograficamente, por densitometria óptica e análise histológica, nos períodos 30, 60 e 90 dias pós-operatórios. Houve superioridade estatística na média geral das avaliações radiográficas do GB (2,33±0,48) sobre o GC (1,77±0,06). As médias gerais de avaliação densitométrica do GB foram superiores às do GC, sendo 6,207±1,374 e 5,71±1,512, respectivamente. A avaliação histopatológica do GB foi superior à do GC nos períodos de 30, 60 e 90 dias. Assim, é possível afirmar que o hidrogel de quitosana constitui biomaterial de características desejáveis, promovendo consolidação óssea mais rápida e eficiente, sem causar reações adversas.

Introducción: Los exoesqueletos de crustáceos constituyen fuentes de obtención de biopolímeros de gran versatilidad, y desechos sólidos que contaminan el medio ambiente. Objetivos: establecer procesos tecnológicos a escala industrial para la obtención de quitosana y sus sales, para aplicaciones biomédicas. Métodos: Una temperatura de mezcla de 80 °C y de reacción de 100 °C/15 minutos dobles, fueron las mejores condiciones para la obtención de la quitosana. Por el método de secado por aspersión se obtuvieron las sales de quitosana, estableciéndose, una temperatura de entrada de 160 °C ± 5 °C y de salida de 100 °C ± 5 °C, a partir de una disolución de quitosana en ácido acético o láctico. Resultados: La caracterización confirmó la obtención de quitosana con un grado de desacetilación superior al 70 % y una masa molecular media de 310 000 g/mol; así como la formación de las sales del biopolímero solubles en agua. Se demostró la homogeneidad de las propiedades de los productos en los lotes escalados y la reproducibilidad de los procesos tecnológicos establecidos, en las condiciones de la industria nacional. Se comprobó la estabilidad física, química y microbiológica del biopolímero y sus sales, durante 24 meses. Se evaluó su capacidad emulgente lográndose la estabilización de sistemas semisólidos. Las bases emulsionadas e hidrosolubles acuosas, empleando quitosana y acetato de quitosana, mostraron adecuada estabilidad física sin interferencias en la liberación del fármaco modelo, quedando demostrada su aplicación como agentes estabilizantes. Conclusiones: se obtuvieron tres nuevas materias primas de producción nacional a escala industrial con calidad, para ser empleadas en la industria farmacéutica.

Copyright of Revista Nacional de Odontología is the property of Universidad Cooperativa de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Resumo Objetivou-se desenvolver, caracterizar e avaliar in vitro biomateriais compósitos de quitosana com hidroxiapatita (CHI/HA) para atuarem como substitutos ósseos. As quitosanas de baixa (L-CHI) e média (M-CHI) massa molecular foram previamente caracterizadas por gravimetria, viscosimetria e espectrofotometria ultravioleta. Os compósitos de CHI/HA foram produzidos por precipitação in situ, seguida de centrifugação (micropartículas) ou spray drying (nanopartículas), e caracterizados por microscopia eletrônica de varredura, espectroscopia de infravermelho com transformada de Fourier e difração de raios X. A citotoxicidade in vitro foi determinada por teste de viabilidade celular. L-CHI e M-CHI apresentaram, respectivamente, 15,7% e 16,4% de umidade, 0,51% e 0,18% de cinzas, 79,5% e 77,7% de grau de desacetilação e 4,18.104 e 17,3.104 de massa molecular média viscosimétrica. Os compósitos exibiram grupos característicos dos materiais de origem e escassa citotoxicidade. Concluiu-se que as técnicas foram eficazes para produção dos biomateriais, com características físico-químicas e biológicas adequadas para utilização nas terapias ósseas.

Biostimulants are used in order to increase the growth, development, yields and quality of crops. The beneficial effect of QuitoMax®, a biostimulant of national production on productive indicators in different crops has been verified, although research on the quality of the agricultural product obtained is limited. In this way, the goal of this work was to evaluate quality parameters of garlic (Allium sativum L.) obtained from two varieties of the Criollo clone: 'Criollo-9'and 'Criollo-Víctor' treated with concentrations of QuitoMax®. Bulbs of both varieties used were obtained from cloves embedded in QuitoMax® concentrations of 1, 5 and 10 mg L-1 before manual planting in flower beds. Fifty days after planting (dap) a foliar application was made with these same doses, maintaining a group of control plants for a total of four treatments per clone. Indicators of external and internal quality were determined, as well as physicochemical properties, protein and carbohydrate content in the garlic extract. The use of QuitoMax® did not significantly change most of the indicators evaluated. The changes found in a few indicators were in the sense of increasing quality and dependent on the variety and concentration of the biostimulant. The use of QuitoMax® in the garlic production system is promising for the benefit of the quality of the agricultural products. [ABSTRACT FROM AUTHOR]

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

No presente trabalho, foram confeccionadas quatro diferentes formulações de membranas à base de quitosana de maneira a tipificar a eficiência da utilização do biopolímero quitosana na adsorção de metais pesados e solubilização. Após a confecção das membranas, foram realizados ensaios de solubilidade, tempo de filtração, absorção atômica e microscopia eletrônica de varredura (MEV). As membranas MQA e MQE, compostas por quitosana 1% + acetato de celulose eme solução de ácido acético 1% e por quitosana 2% e solução de ácido acético 1%,respectivamente, apesentaram bons resultados na análise de solubilidade, tempo de filtração e homogeneidade da superfície, evidenciado pelas fotos de MEV. Conclui-se, portanto, com base nas análises realizadas no presente trabalho, que, devido a capacidade de o biopolímero quitosana formar complexos com íons metálicos e ser economicamente viável, esta apresenta-se como alternativa para ser estudada no desenvolvimento de novas formulações a serem testadas em processos de filtração por membranas, sobretudo pelo evidente aumento da adsorção de alguns metais pesados.

No intuito de se obter melhorias no desempenho de embalagens, materiais inovadores a base de fontes renováveis vêm sendo desenvolvidos, visando sobretudo a substituição total ou parcial do uso de polímeros sintéticos como revestimentos de embalagens celulósicas. O biopolímero quitosana, assim como o amido, são matérias primas de interesse, ambos detentores de grande aplicação, tanto na alimentação humana e animal, quanto na indústria de embalagens. No âmbito desse contexto, o presente trabalho teve como objetivo, caracterizar folhas de papel cartão revestidas com solução filmogênica à base de quitosana e amido. Para tanto, foram realizadas análises de espessura, gramatura, Microscopia Eletrônica de Varredura (MEV), Taxa de Permeabilidade ao Vapor D’água (TPVA), Absorção D’água (Cobb), onde houveram melhorias nos resultados quando comparados com amostras de papel cartão sem revestimento. Somente a análise de resistência à tração, não apresentou alterações significativas.

El empleo de los bioestimulantes en la agricultura ha crecido en los últimos años, como una práctica agroecológica importante. La Spirulina y la vinaza poseen propiedades que favorecen el crecimiento y desarrollo de los cultivos, mejorando así la calidad nutricional de los mismos. El objetivo del presente trabajo fue determinar el efecto de un bioestimulante, compuesto por una suspensión acuosa de jalea de Spirulina y vinaza, aplicado solo o en combinación con otros bioestimulantes, en la producción de granos en el cultivo del frijol. Para esto, se montaron dos experimentos con el cultivar 'Inqueño'. En el primero se realizaron dos aspersiones foliares con dos dosis equivalentes a 3,5 y 7 L ha-1 del nuevo bioestimulante y en el segundo, se realizaron también dos aspersiones, la primera con el nuevo bioestimulante (2,5 L ha-1) y la segunda se efectuó con el nuevo bioestimulante a igual dosis o con Quitomax® o con la combinación de ambos. La aplicación del nuevo bioestimulante, a base de Spirulina y vinaza estimuló la productividad del frijol común, pero los resultados fueron más prominentes cuando se aplicó en combinación con el Quitomax® y se biofertilizó con Azofert®, que podría constituir una alternativa eficiente para incrementar el rendimiento de este cultivo. [ABSTRACT FROM AUTHOR]

Copyright of Ceramica is the property of Associacao Brasileira de Ceramica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

La conservación de los productos hortofrutícolas en la postcosecha es un tema de vital importancia debido a las grandes pérdidas que se generan durante la comercialización interna de un país, así como en la exportación. Estas pérdidas se deben al deterioro microbiológico y fisiológico, a un proceso de recolección inadecuado, al empleo de empaques no adecuados y a vías para la transportación insuficientes. El empleo de recubrimientos biodegradables en forma de películas constituye una alternativa que permite disminuir estas pérdidas. Los recubrimientos biodegradables generalmente están compuestos por carbohidratos, proteínas y lípidos de forma individual o combinados entre sí. Estos recubrimientos constituyen una barrera semipermeable al vapor de agua, el dioxígeno (O2) y el dióxido de carbono (CO2) entre los frutos y la atmosfera circundante. De manera general retardan el proceso de senescencia y el crecimiento microbiano en la superficie del fruto, lo que permite preservar la calidad y facilitar la distribución y la comercialización de estos. Por las potencialidades y la importancia que este tipo de tecnología presenta en la actualidad, en nuestro contexto nacional se realiza esta revisión, teniendo en cuenta los principales componentes empleados en la obtención de estos materiales, la aplicación práctica en productos hortofrutícolas y los principales análisis que se realizan para su caracterización. [ABSTRACT FROM AUTHOR]

Modification of chitosan with biocompatible synthetic polymers is important for the development of biodegradable medical materials with a tailor-made complex of properties. The issue of the influence of a polysaccharide macromolecule conformation on the synthesis and properties of the hybrid products remains acute. Conformational transitions of chitosan and their influence on the process of grafted polymerization of 2-hydroxyethyl methacrylate and N-vinylpyrrolidone onto the polymer and the properties of their copolymers were studied. To interpret the peculiarities of chitosan solutions properties, their viscosity was identified by the method of rotational viscometry; conformational transitions of the polymer polysaccharides were investigated by the method of spectrophotometry; dimensional characteristics of the polymer particles were assessed by the method of dynamic light scattering. Copolymers were characterized by the methods of IR-spectroscopy and gelpenetrating chromatography. Helix-coil conformational transition of the chitosan macromolecule was pH and temperature-sensitive. The effective size of the chitosan macromolecules for helix conformation was 14-35% larger than for the coil conformation. The grafted copolymer yield (98%) was significantly higher in the solutions of chitosan, where its macromolecules were in the coil conformation. The obtained results allow the researchers to create optimal conditions during the development of the copolymer-based biomedical materials with improved characteristics. [ABSTRACT FROM AUTHOR]

Copyright of Innotec is the property of Laboratorio Tecnologico del Uruguay and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Brasileira de Saúde e Produção Animal (RBSPA) is the property of Revista Brasileira de Saude e Producao Animal (RBSPA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Eletrônica de Materiais e Processos is the property of Revista Eletronica de Materiaia e Processos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Em busca de um correto direcionamento a rejeitos, vê-se na produção de materiais cerâmicos a possibilidade potencial de reaproveitamento a partir da junção de resíduos e compostos biopoliméricos, que venham a conferir melhores características básicas aos produtos cerâmicos. Os resíduos de lapidários e o biopolímero quitosana, têm em sua composição uma diversidade de minerais que ampliam a possibilidade de aplicação na indústria cerâmica. No presente trabalho, foram confeccionados corpos de prova com diferentes proporções de pó de lapidário e argila, sendo a água para o preparo da massa, substituída por solução de quitosana 2% (em massa). Após os processos de queima nas temperaturas de 850, 950 e 1100°C, os corpos de prova foram submetidos a análise de Difusividade segundo a lei de Fick. Donde foi possível concluir que a adição de pó de lapidário diminuiu a taxa de difusão e o ganho de massa nas amostras, mostrando um incremento nas características desejáveis para os produtos. In search of an adequate destination of residues, the reuse is seen in the production of ceramic materials from the junction of residues and biopolymer compounds, which will confer better characteristics to the ceramic products. The residues of lapidary and the biopolymer chitosan have in their composition minerals that extend the possibility of application in the ceramic industry. In the present work, specimens were prepared with different proportions of lapidary powder and clay, the water for the preparation of the mass being replaced by chitosan solution 2% (w/w). After the processes of burns at 850, 950 and 1100°C, the specimens were submitted to analysis of Diffusivity according to Fick’s law. It was concluded that the addition of lapidary powder decreased the diffusion rate and the mass gain in the samples, showing an increase in desirable characteristics for the products.

Galactomanana (Gal) é um polissacarídeo que possui estrutura linear, constituída principalmente de unidades de D-manopiranose por uma ligação β(1-4) com moléculas de D-galactopiranose na cadeia principal unidas por uma ligação glicosídica. A estrutura química da quitosana (Q) é formada por unidades de β(1-4) 2-amino-2-deoxi-D-glucose repetidamente. A espectroscopia dielétrica é uma caracterização que estuda a resposta de um material através de um estímulo elétrico, normalmente sendo esta uma corrente alternada, e assim, estudar a parte real e imaginária da impedância e de outros termos dependentes da mesma. Este trabalho tem por objetivo produzir filmes poliméricos usando Galactomanana e Quitosana e caracterizá-los por espectroscopia dielétrica. As soluções dos polissacarídeos foram preparadas a uma proporção de 2%. Em seguida, as soluções de galactomanana 2% e a solução de quitosana 2% foram misturadas e solubilizadas para a obtenção dos filmes de Gal, Q e da blenda GalQ. A blenda da GalQ foi caracterizado por espectroscopia dielétrica. Conclui-se que os filmes apresentam características elétricas dos polímeros isolantes.

Copyright of Revista do Instituto de Laticínios Cândido Tostes is the property of Revista do Instituto de Laticinios Candido Tostes and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Eletrônica de Materiais e Processos is the property of Revista Eletronica de Materiaia e Processos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ceramica is the property of Associacao Brasileira de Ceramica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effect of various acids on the thermal properties of chitosan films was evaluated. Films 100 µm thick were prepared from chitosan solutions in different acids: acetic, citric, lactic, maleic, tartaric, hydrochloric and nitric acid. The films were analyzed by infrared spectroscopy, X-ray diffractionand thermal analysis. They were transparent and flexible and less crystalline that the chitosan powder. The nature of the acid influenced the intra-and intermolecular interactions in chitosan films, which is reflectedbythe shift to higher frequencies of the bands at 2 942-2 784 cm-1 and the shift to lower frequencies of the bands at 1 650, 1 590, 1 420 and 1 376 cm-1 in theinfrared spectra. The thermal stability of films was lower than that of chitosan and each acid had a difference influence on it.It was concluded that the selection of the acid solvent to prepare chitosan films is important in determining its properties. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Thermal Analysis is the property of Brazilian Journal of Thermal Analysis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The packaging industry is one of the most important sectors of the economy, recognized and diagnosed as strategic for society. With this, technologies have arisen aiming at sustainable development and the search for materials that minimize damages to the environment. At the same time, the need for innovation, quality assurance and practicality to be offered to the consumer, there is concern about its final destination in an economical and environmentally correct way. Included in this context are the cellulosic packaging and the substitution of coatings based on synthetic polymers by natural polymers. In the present work, coatings based on the chitosan biopolymer were developed with the addition of natural dyes: anthocyanin and urucum (Bixa Orellana L.), entitled PCA2 and PCU2, respectively. Samples of paper (277 g/m2) were coated and characterized as Scanning Electron Microscopy (SEM), thickness, weight and barrier properties: WVPR, COBB and tensile strength. Weight and tensile strength analyzes showed no statistical differences. There was a reduction of WVPR of the order of 38.6% and 24.2% for the PCA2 and PCU2 samples, respectively, when compared to uncoated samples (PU). Similar fact occurred with the COBB analysis, there was reduction of the order of 14.8% and 29.62%. [ABSTRACT FROM AUTHOR]

A nanotecnologia é o termo utilizado para descrever a criação, manipulação e exploração de materiais em escala nanométrica. Bionanotecnologia é a aplicação da nanotecnologia nas ciências da vida, onde a matéria prima para obtenção de nanopartículas é de origem biológica. Esta ciência tem despertado grande interesse por ser de fontes renováveis, pela possibilidade de obtenção de novas propriedades dos materiais, que em dimensão nano, são totalmente modificadas, pela maior possibilidade de biocompatibilidade com o organismo humano, pelo auxílio em tratamentos mais eficazes de doenças (liberação controlada de fármacos), bem como no diagnóstico preventivo na área da saúde (agentes de imagem) e no controle de qualidade dos produtos da agroindústria (biossensores). O objetivo desta revisão foi abordar as bionanopartículas de maior evidência no campo da nanotecnologia, enfatizando as nanopartículas de quitosana, nanofibras de celulose e recentes estudos com Spirulina platensis, focando em seus processos de obtenção, suas características em escala nanométrica e suas aplicações nos diversos campos da ciência e tecnologia.

Resumo Este trabalho teve como objetivo determinar o efeito da inclusão de óleos essenciais (EOs) e do armazenamento na cor dos filmes de quitosana (CH) para os parâmetros de L*, a*, b* e ΔE. Os óleos essenciais de tomilho (TEO) e alecrim (REO) foram incluídos em concentrações de 0,5:1 e 1:1 p/p (EOs:CH), assim como suas combinações 50/50 (TEO:REO). Os filmes foram armazenados a temperaturas de 5 °C, 20 °C e, 33 °C e umidade relativa do ar de 60%, 75% e, 93% durante quatro semanas. Os parâmetros da cor foram determinados por refletância com componente especular incluído (RSIN) e por refletância com componente especular excluído (RSEX), usando seis padrões de fundos diferentes. A inclusão e o aumento da concentração de óleos essenciais, assim como o aumento do tempo, da temperatura e da umidade e o padrão de fundo alteraram os valores das variáveis resposta.

Resumo Esferas de goma do cajueiro carboximetilada e quitosana foram produzidas via complexação polieletrolítica. As esferas foram modificadas quimicamente de modo a obter-se sistemas estáveis em meio ácido e que apresentassem uma resposta de intumescimento diferenciado frente à variação de pH. As esferas foram modificadas por reacetilação da quitosana e por reticulação com epicloridrina, glutaraldeído e genipina. As esferas reticuladas foram caracterizadas por meio de técnicas como: espectroscopia de absorção no infravermelho, análise termogravimétrica, microscopia eletrônica de varredura e quanto à solubilidade em pH 1,2 e ao intumescimento. As esferas de goma do cajueiro carboximetilada e quitosana reacetilada, e as esferas reticuladas com epicloridrina apresentaram baixa resistência à dissolução em pH 1,2. Entretanto, as esferas reticuladas com glutaraldeído e genipina apresentaram resistência à dissolução e baixo coeficiente de difusão. As esferas reticuladas com genipina apresentaram um grau de intumescimento maior do que as esferas reticuladas com glutaraldeído nas concentrações de 3% e 5% (massa/volume). As esferas reticuladas com genipina apresentaram intumescimento responsivo à variação de pH e estabilidade em pH 1,2, indicando que esses sistemas possuem potencial para uso em sistemas de liberação controlada de fármacos por via oral.