PREPARAÇÃO E CARACTERIZAÇÃO DE MEMBRANAS DE CELULOSE REGENERADA A PARTIR DA CELULOSE EXTRAÍDA DE RESÍDUOS AGROINDUSTRIAIS PARA APLICAÇÃO EM PROCESSOS DE SEPARAÇÃO

The aim of this study was to produce membranes using the adapted cuprammonium method. The cellulose utilized was obtained from recycled agroindustrial residues: sugarcane bagasse, corn stover and soybean hulls. The levels of Cu (II) ions in regenerated cellulose membranes produced with cellulose from bagasse, corn stover and soybean hulls were 0.0236 wt%, 0.0255 wt% and 0.0268 wt%, respectively. These levels were approximately 15 times lower than those observed in previous studies (0.3634 wt%). Cellular viability data show that membranes produced from bagasse cellulose do not present toxicity to the cellular cultures studied. These results demonstrate an evolution in production of regenerated cellulose membranes from agroindustrial residues mainly due to a decrease in the Cu (II) ions level, showing the possibility of application of these systems with improved membranes processing.

PARÂMETROS TERMODINÂMICOS DA CASCA DE LARANJA DESIDRATADA

The global energy scenario is currently a widely discussed topic, with growing concern about the future supplies. Thus, much attention has been dedicated to the utilization of biomass as an energy resource. In this respect, orange peel has become a material of great interest, especially to Brazil, which generates around 9.5 million tons of this waste per year. To this end, the authors studied the kinetics of the thermal processing of dried orange peel in inert and oxidizing atmosphere. The thermodynamic parameters were determined by the Ozawa-Flynn-Wall method for the global process observed during heating from the 25°C up to 800°C. The thermal analysis in air and nitrogen showed 3-2 stages of mass loss, respectively, with approximately 20% residual mass under a nitrogen atmosphere. The increase in the values of activation energy for the conversion points between 20% and 60% for thermal effects in air and nitrogen atmosphere was observed. The activation energy obtained in an oxidizing atmosphere was higher than that obtained under a nitrogen atmosphere. The fourier-transform infrared spectroscopy and X-ray diffraction analysis showed that the material has a high level of complexity with the presence of alkali and alkaline earth groups as well as phosphate, plus substances such as pectin, cellulose and lignin.

PYROLIGNEOUS LIQUOR PRODUCED FROM ACACIA MEARNSII DE WILD WOOD UNDER CONTROLLED CONDITIONS AS A RENEWABLE SOURCE OF CHEMICALS

Acacia mearnsii de Wild (black wattle) is one of the most important trees planted in Southern Brazil for tannin extraction and charcoal production. The pyrolysis of the black wattle wood used for obtaining charcoal is performed in brick ovens, with the gas fraction being sent directly into the environment. The present study examines the condensable compounds present in the liquor produced from black wattle wood at different thermal degradation conditions, using gas chromatography coupled with mass spectrometry (GC/MS). Branches of black wattle were thermally degraded at controlled ambient and temperature conditions. Overall, a higher variety of compounds were obtained under atmospheric air pressure than under synthetic air pressure. Most of the tentatively identified compounds, such as carboxylic acids, phenols, aldehydes, and low molecular mass lignin fragments, such as guayacol, syringol, and eugenol, were products of lignin thermoconversion. Substituted aromatic compounds, such as vanillin, ethyl vanillin, and 2-methoxy-4-propeny-phenol, were also identified. At temperatures above 200 ºC, furan, 2-acetylfuran, methyl-2-furoate, and furfural, amongst others, were identified as polysaccharide derivatives from cellulose and hemicellulose depolymerization. This study evidences the need for adequate management of the condensable by-products of charcoal production, both for economic reasons and for controlling their potential environmental impact.

NANOCRISTAIS DE CELULOSE A PARTIR DE CELULOSE BACTERIANA

Bacterial cellulose produced from Gluconacetobacter xilinus was used to produce cellulose nanocrystals by sulfuric acid hydrolysis. Hydrolysis was performed with 64% sulfuric acid at 50 ºC with the hydrolysis time ranging between 5 and 90 min. The production of nanocrystals was observed to have size distributions that were dependent on hydrolysis times up to 10 min, after which time the suspensions showed distributions closer in size. Results from thermal analysis and X-ray diffraction showed that the amorphous cellulose was removed, leaving only the crystalline portion. Self-supported films were formed from the suspension of nanocrystals and had iridescence characteristics. The films were characterized by microscopy measures and specular reflectance.

OBTENÇÃO DE COMPÓSITOS HÍBRIDOS BASEADOS EM HIDROGÉIS E CIMENTO PORTLAND

In this study, a novel hybrid composite based on biodegradable hydrogel and Portland cement with promising technological properties was reported. In the first step, a full 23 with central point factorial design was utilized to obtain the enhanced polyacrylamide-carboxymethylcellulose hydrogel compositions. A mathematical model was devised, indicating that the 3 main variables were significant and the AAm and MBAAm variables positively contributed to the mode and showing that the CMC variable had the opposite contribution. In the second step, these compositions were mixed with Portland cement to obtain the hybrid composites. The presence of cement improved the mechanical properties of polymeric matrices, and electronic microscopic micrographics revealed that the hydrogels were well adhered to the cement phase and no phase separation between hydrogel and cement was detected. Finally, using the energy dispersive X-ray technique, the elements Na, Mg, Al, Si, S, K, Ca and Fe were detected in the polymeric matrix, consistent with the hybrid composite formation.

Potentiometric determination of captopril in pharmaceutical formulations

A simple, precise, rapid and low-cost potentiometric method for captopril determination in pure form and in pharmaceutical preparations is proposed. Captopril present in tablets containing known quantity of drug was potentiometrically titrated in aqueous solution with NaOH using a glass pH electrode, coupled to an autotitrator. No interferences were observed in the presence of common components of the tablets as lactose, microcrystalline cellulose, croscarmellose sodium, starch and magnesium stearate. The analytical results obtained by applying the proposed method compared very favorably with those obtained by the United States Pharmacopoeia Standard procedure. Recovery of captopril from various tablet dosage formulations range from 98.0 to 102.0%.

Lability of Cd, Cr, Cu, Mn and Pb complexed by aquatic humic substances

The lability of Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) complexed by humic substances (HSs) was investigated by means of ion exchange on cellulose modified with p-aminobenzoic groups (Cell-PAB), using a batch procedure. The HSs were extracted from water samples using adsorption in a column packed with XAD 8 resin. The metal-HS complexes were prepared by adding solutions containing all the aforementioned metal ions ( Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) ). The results indicated that the distribution coefficients (Kd) of Cell-PAB decreased with the presence of HSs, and that the lability of metal fractions complexed by HSs decreases in pH values > 4.0, complexation time > 10 h and HS concentration > 500 mg L-1. The metal exchange between HSs and Cell-PAB exhibited the following order of metal ion lability: Cd < Pb < Mn @ Cr < Cu.

A fluorescence probe study of gemini surfactants in aqueous solution: a comparison between n-2-n and n-6-n series of the alkanediyl-a,w-bis (dimethylalkylammonium bromides)

Two series of alkanediyl-a,w-bis (dimethylalkylammonium bromide (n-2-n and n-6-n; n=8, 10,12, and 16) have been synthesized and their micelles properties studied in aqueous solution using pyrene, pyrenecarboxaldehyde (PCA) and 1,8 anilinonaphtalene sulfonic acid sodium salt (ANS) as fluorescent probes. The micelles from these surfactants have been characterized on the basis of the information provided by micelle-solubilized fluorescent probes. The obtained results indicated that the surfactant concentration at which a marked decrease in l max parameter of pyrenecarboxaldehyde (PCA) occurs corresponds to the CMC determined by conductimetric measurements. Changes in the emission spectra of ANS and PCA observed in the submicellar range for both surfactants series (n-2-n and n-6-n) were interpreted as formation of pre-aggregates. It was found that the dimeric surfactants with long spacer (s= 6) form more hydrated aggregates when compared with those formed by the n-2-n and CnTAB surfactants series. This was attributed to a more difficult packing of n-6-n surfactant molecules to form micelles.

Desenvolvimento de Pantoea agglomerans em diversas temperaturas, pH e concentrações de carboxi-metil-celulose e o seu impacto no controle de Rosellinia necatrix

Rosellinia necatrix Prill induz a podridão branca da raiz da macieira, doença que causa severa perda em pomares localizados no sul do Brasil. O manejo da doença é principalmente preventivo e inclui o uso de porta-enxertos resistentes e a fumigação do solo. A proteção das mudas de macieiras antes do plantio com um isolado antagonista de Pantoea agglomerans foi recentemente proposto para reduzir a incidência da doença. Os objetivos desta pesquisa foram caracterizar o relacionamento entre o patógeno e a bactéria antagonista; a produção de metabólitos biológicamente ativos pelo isolado bacteriano e a sua ação sobre o patógeno; o efeito do pH, da temperatura e de carboxi-metil-celulose (CMC) sobre o crescimento do antagonista e do patógeno, isolados ou não e no controle da doença. Os resultados demonstraram que o crescimento de P. agglomerans foi maior em pH 5,5 e 6,0 e nas temperaturas de 20 °C e 30 °C. O crescimento micelial de R. necatrix foi inibido em meio de cultura e previamente colonizado pelo antagonista e com CMC nas concentrações de 0,25 e 0,5 %. A proteção das macieiras da infecção por R. necatrix foi observada quando utilizadas as concentrações de 10(7); 10(8) e 10(9) cel/mL e nas diferentes concentrações de CMC. Maior desenvolvimento radicular das macieiras foi constatado em todas as concentrações de CMC quando usada a concentração de 10(9) cel/mL. A formulação de P. agglomerans com CMC tornará possível a incorporação desta estratégia de controle ao manejo integrado da podridão branca das raízes da macieira no Sul do Brasil.

Cylindrocladium spathiphylli de espatifilo (Spathiphyllum wallisii Rengel): detecção de enzimas extracelulares em isolados normais e alterados por temperatura

O fungo Cylindrocladium spathiphylli causa podridão no colo e nas raízes de espatifilo, induzindo amarelecimento e murcha nas folhas da parte aérea. Há poucos estudos com o fungo quanto às enzimas extracelulares. Assim, delineou-se ensaio inteiramente casualizado in vitro, com três tratamentos (dois isolados normais: LFEEI016 - EPAGRI/SC e MMBF 01/01 - IB/SP; mais testemunha) e seis repetições, visando a detecção de enzimas. A amilase (AM), lipase (LP), carboximetilcelulase (CMC) e lacase (LC) foram mensuradas pelo cálculo da área da coroa circular, local de atividade das enzimas. A catalase (CT) e gelatinase (GL) foram mensuradas por símbolos, depois transformados em notas (1 a 4, de ausência à intensa produção). O isolado MMBF 01/01 produziu as maiores áreas e com mais intensidade as enzimas. Das enzimas, a maior área foi a da LC e depois a LP. LFEEI016 e MMBF 01/01 não apresentaram área para AM e CMC e exibiram intensidade fraca e igual para CT. A intensidade de GT foi moderada no MMBF 01/01 (nota média 3,0) e ausente para o LFEEI016 (nota média 1,0). Após a produção das enzimas extracelulares, os isolados foram alterados vegetativamente por temperatura. Instalou-se ensaio inteiramente ao acaso, em fatorial contendo disco de micélio dos isolados do fungo versus três temperaturas [23ºC (T1); 33ºC (T2) e de 33ºC para 23ºC (T3)] versus quatro períodos (3; 6; 9 e 12 dias), com oito repetições, em placa de Petri com BDA mantida em BOD. O diâmetro das colônias foi medido diariamente (mm) em dois sentidos. As alterações de temperatura vistas foram: inócuo, fungistático (FS) e fungicida (FC). Aplicou-se estatística nas temperaturas T1 e T3 dos isolados para checar efeito FS e escolher aqueles com maior e menor efeito. O isolado LFEEIO16 mostrou efeito FS com três dias às temperaturas 33ºC e de 33ºC para 23ºC. Nos demais períodos, o isolado sofreu efeito FC. O MMBF 01/01 mostrou efeito FS em todos os períodos. Ambos isolados sofreram, estatisticamente, efeito FS. O MMBF 01/01 mostrou maior efeito FS aos nove dias, nas temperaturas referidas e menor com três dias. Após a constatação de alteração na taxa de crescimento micelial dos isolados, procurou-se verificar, novamente, a produção de enzimas extracelulares. Os isolados alterados e utilizados foram o MMBF 01/01 com três e nove dias e o LFEEIO16 com três dias. A produção e a avaliação das enzimas foram realizadas da mesma maneira para os isolados normais. O isolado MMBF 01/01 - três dias produziu as maiores áreas e com mais intensidade as enzimas. Das enzimas, a maior área foi a da LC. Após LC, a área da LP foi maior que a da CMC nos isolados. Não se detectou área de AM nos isolados. A intensidade de GL foi maior que a da CT nos isolados MMBF 01/01 com três e nove dias. Para LFEEI016 - três dias, a intensidade média de CT foi nota 2,0 e ausência de GL (nota média 1,3). Sugere-se investigar a severidade da doença na planta entre os isolados e em condições naturais investigar a evolução da LC em comparação as demais enzimas na patogênese do fungo na cultura.

Mapping of QTLs related with wood quality and developmental characteristics in hybrids (Eucalyptus grandis x Eucalyptus urophylla)

The present work aimed to characterize and identify QTLs for wood quality and growth traits in E. grandis x E. urophylla hybrids. For this purpose a RAPD linkage map was developed for the hybrids (LOD=3 and r=0.40) containing 52 markers and 12 linkage groups. Traits related to wood quality and growth were evaluated in the QTL analyses. QTL analyses were performed using chi-square tests, single-marker, interval mapping and composite interval mapping analyses. All approaches led to the identification of similar QTLs associated with wood density, cellulose pulp yield and percentage of extractives, which were detected and confirmed by both the interval mapping and composite interval mapping methodologies. Some QTLs regions were confirmed only by the composite interval mapping methodology: percentage of soluble lignin, percentage of insoluble lignin, CBH and total height. Overlapping QTLs regions were detected, and these, can be the result of major genes involved in the regulation and control of the growth traits by epistatic interactions. In order to evaluate the effect of early selection using RAPD molecular data, molecular markers adjacent to QTLs were used genotype selection. The analysis of selection differential values suggests that for all the traits the phenotypic selection at seven years should generate larger genetic gains than early selection assisted by molecular markers and the combination of the strategies should elevate the selection efficiency.

Reproductive ecology of the exotic tree Muntingia calabura L. (Muntingiaceae) in southeastern Brazil

The exotic tree Muntingia calabura L. (Muntingiaceae), a species native to Central America, is used as fish feed and fiber and cellulose production in Brazil. This study was carried out in urban areas and verified the reproductive biology of this plant species. Flower and fruit morphology, compatibility system, reproductive phenology, pollination and frugivore animals, and germination of disseminated seeds were recorded by standard field and laboratory procedures. This tree is self-compatible and autonomously self-pollinated, with its flowers being mainly visited by bees and its fruits consumed by birds and bats. Germination of its dispersed seeds is fast and occurs at a high rate. The results of this work suggest that M. calabura is very adaptable to cultivated areas,thus being an excellent choice for urban reforestation. However, its reproductive characteristics place this plant as an invasive species with significant potential in southeastern Brazil.

Influência de aderências peritoneais e fio cirúrgico na tensão de ruptura da parede abdominal em ratos

O resultado de operações na cavidade abdominal pode ser influenciado por aderências. Existem muitos conceitos ainda não comprovados sobre os efeitos das aderências na resistência de suturas tanto de vísceras intracavitárias quanto da parede abdominal. O presente trabalho visa a avaliar a influência das aderências peritoneais e vários tipos de fios cirúrgicos na tensão de ruptura da parede abdominal. Em 60 ratos Wistar, realizou-se laparotomia de 5cm de comprimento. A parede muscular e o peritônio foram fechados em plano único, com pontos simples, usando aleatoriamente os fios de náilon monofilamentar, ácido poliglicólico, categute simples e categute cromado, todos 4-0. Os animais foram divididos em três grupos: 1- Controle; 2- INTRODUÇÃO de 0,3g de talco dentro da cavidade abdominal; 3- Acréscimo de carboximetilcelulose sódica (CMC) juntamente com o talco. Houve a análise dos grupos com sete e 21 dias. Avaliou-se o grau de aderências e a tensão de ruptura da ferida cirúrgica. A CMC reduziu a formação de aderências provocadas pelo talco (p<0,01). Houve diferença na tensão de ruptura quando comparados os grupos de sete e 21 dias (p<0,05). As aderências proporcionaram uma maior força tênsil à ferida (p<0,01). O tipo de fio utilizado não influenciou na tensão de ruptura a longo prazo. Portanto, as aderências aumentaram a força tênsil dos tecidos e o tipo de fio cirúrgico não influenciou nesse processo.

Use of surgical mesh of different compositions in the correction of the abdominal wall defect in rats

Objective: To analyze the performance of two surgical meshes of different compositions during the defect healing process of the abdominal wall of rats. Methods: thirty-three adult Wistar rats were anesthetized and subjected to removal of an area of 1.5 cm x 2 cm of the anterior abdominal wall, except for the skin; 17 animals had the defect corrected by edge-to-edge surgical suture of a mesh made of polypropylene + poliglecaprone (Group U - UltraproTM); 16 animals had the defect corrected with a surgical mesh made of polypropylene + polidioxanone + cellulose (Group P - ProceedTM). Each group was divided into two subgroups, according to the euthanasia moment (seven days or 28 days after the operation). Parameters analyzed were macroscopic (adherence), microscopic (quantification of mature and immature collagen) and tensiometric (maximum tension and maximum rupture strength). Results : there was an increase in collagen type I in the ProceedTM group from seven to 28 days, p = 0.047. Also, there was an increase in the rupture tension on both groups when comparing the two periods. There was a lower rupture tension and tissue deformity with ProceedTM mesh in seven days, becoming equal at day 28. Conclusion : the meshes retain similarities in the final result and more studies with larger numbers of animals must be carried for better assessment.

Immunohistochemical detection of Clostridia species in paraffin-embedded tissues of experimentally inoculated guinea pigs

Blackleg is caused by Clostridium chauvoei, whereas malignant oedema is caused by C. chauvoei, C. septicum, C. sordellii, C. perfringens type A, and/or C. novyi type A. Anti-C. chauvoei, anti-C. septicum, anti-C. sordellii and anti-C. novyi type A polyclonal antibodies were produced in rabbits and purified in a column of DEAE-cellulose. Aliquots of the antisera were conjugated with fluorescein isothiocyanate and the remaining was used for the streptavidin biotin peroxidase technique (SBPT). SBPT was standardized to detect C. chauvoei, C. septicum, C. sordellii and C. novyi type A in formalin-fixed, paraffin-embedded tissues of guinea pigs. SBPT was compared to a fluorescent antibody technique (FAT). Sections and smears of muscle from inoculation area (MIA), heart, liver, spleen and kidney, were obtained for both SBPT and FAT. Cross-reactions between the different Clostridial species were not observed. C. chauvoei and C. septicum were detected in all specimens from the animals inoculated with these microorganisms, while only sections of muscle obtained from all the animals inoculated with C. sordellii and C. novyi type A were positive. The same results observed by the SBPT, were obtained on tissue smears of these microorganisms stained by the FAT. The results indicate that SBPT is suitable for detection of C. chauvoei, C. septicum, C. sordellii and C. novyi type A in formalin-fixed, paraffin-embedded tissues of guinea pigs.