1,208 research outputs found
Obtención de hidrolizado de aceite de macauba y su aplicación en la producción de ésteres metílicos
This work aimed to obtain a hydrolyzate rich in free fatty acids (FFA) from the hydrolysis of macauba oil for subsequent esterification and obtaining of methyl esters. To determine the conditions that maximize FFA yield in the hydrolysis step, the effects of buffer solution percentage and catalyst concentration (Lipozyme® RM IM) were determined at 55 ºC and 6 h. From the results, it was verified that both variables evaluated in the experimental range had an influence on the reaction and their increase favored the production of FFA. Additional experiments were carried out to assess the influence of reaction time with a progressive increase up to 8 h. Hydrolyzate with ~92 wt % FFA was obtained and its use in the enzymatic esterification step using Novozym® 435 as catalyst resulted in ~95 % FFA conversion. Regarding the reuse of enzymes at each stage, a ~50 % reduction in FFA yield was found and only 98 % FFA conversion.Este trabajo tuvo como objetivo obtener un hidrolizado rico en ácidos grasos libres (AGL) a partir de la hidrólisis del aceite de frutos de macauba, para su posterior esterificación y obtención de ésteres metílicos. Para determinar las condiciones que maximizan el rendimiento de AGL en la etapa de hidrólisis, se determinaron los efectos del porcentaje de solución amortiguadora y la concentración de catalizador (Lipozyme® RM IM) a 55 ºC y 6 h. De los resultados se verificó que ambas variables, en el rango experimental evaluado, tienen influencia en la reacción y su incremento favorece la producción de AGL. Se llevaron a cabo experimentos adicionales para evaluar la influencia del tiempo de reacción, observándose un aumento progresivo hasta las 8 h. Se obtuvo un hidrolizado con ~92 % en peso de FFA y su uso en el paso de esterificación enzimática, usando Novozym® 435 como catalizador, resultó en ~95 % de conversión de FFA. Al investigar la reutilización de enzimas, en cada etapa, se encontró una reducción de ~50 % en el rendimiento de FFA y solo un 98 % en la conversión de FFA
Aceite de semilla de maracuyá: extracción y posterior reacción de transesterificación
This work aims to remove the oil from passion fruit seeds using ethanol as solvent and then to carry out the transesterification of the product from the extraction step (oil + ethanol). The effects of operational variables in the ultrasound-assisted extraction (UAE) were evaluated and traditional extraction was performed for comparison. The extraction product was directed to the reaction step using an enzymatic catalyst. UAE provided oil yield from 12.32 to 21.76%, and the maximum value (73.7% of the traditional extraction yield) was obtained at 60 °C and 50 min using a solvent-to-seed ratio of 4. Oil removal was favored by increases in the investigated variables. g-tocopherol, δ-tocopherol and a high concentration of polyunsaturated fatty acids were identified in the oils. The oil obtained by UAE presented higher phytosterol contents. From the reaction step, samples were obtained with higher concentrations of ethyl esters, in addition to emulsifiers (diglycerides and monoglycerides).Este trabajo tiene como objetivo la extracción del aceite de la semilla de maracuyá utilizando etanol como disolvente y posteriormente llevar a cabo la transesterificación del producto obtenido (aceite + etanol). Se evaluaron los efectos de las variables operativas en la extracción asistida por ultrasonido (EAU) y se realizó la extracción clásica a efectos comparativos. El producto de extracción se dirigió a la etapa de reacción usando catalizador enzimático. EAU proporcionó un rendimiento de aceite de 12,32 a 21,76%, y el valor máximo (73,7% del rendimiento de extracción clásico) se obtuvo a 60 °C durante 50 min usando una relación de solvente a semilla de 4. La extracción de aceite se favorece con el aumento de las variables investigadas. Se identificaron en los aceites g- y δ-tocoferol y una alta concentración de ácidos grasos poliinsaturados. El aceite obtenido por los EAU presentó un mayor contenido de fitosteroles. De la etapa de reacción, se obtuvieron muestras con concentraciones más altas de ésteres etílicos, además de emulsionantes (diglicéridos y monoglicéridos)
Disentangling the drivers of reduced long-distance seed dispersal by birds in an experimentally fragmented landscape
Seed dispersal is a crucial component of plant population dynamics. Human landscape modifications, such as habitat destruction and fragmentation, can alter the abundance of fruiting plants and animal dispersers, foraging rates, vector movement, and the composition of the disperser community, all of which can singly or in concert affect seed dispersal. Here, we quantify and tease apart the effects of landscape configuration, namely, fragmentation of primary forest and the composition of the surrounding forest matrix, on individual components of seed dispersal of Heliconia acuminata, an Amazonian understory herb. First we identified the effects of landscape configuration on the abundance of fruiting plants and six bird disperser species. Although highly variable in space and time, densities of fruiting plants were similar in continuous forest and fragments. However, the two largest-bodied avian dispersers were less common or absent in small fragments. Second, we determined whether fragmentation affected foraging rates. Fruit removal rates were similar and very high across the landscape, suggesting that Heliconia fruits are a key resource for small frugivores in this landscape. Third, we used radiotelemetry and statistical models to quantify how landscape configuration influences vector movement patterns. Bird dispersers flew farther and faster, and perched longer in primary relative to secondary forests. One species also altered its movement direction in response to habitat boundaries between primary and secondary forests. Finally, we parameterized a simulation model linking data on fruit density and disperser abundance and behavior with empirical estimates of seed retention times to generate seed dispersal patterns in two hypothetical landscapes. Despite clear changes in bird movement in response to landscape configuration, our simulations demonstrate that these differences had negligible effects on dispersal distances. However, small fragments had reduced densities of Turdus albicollis, the largest-bodied disperser and the only one to both regurgitate and defecate seeds. This change in Turdus abundance acted together with lower numbers of fruiting plants in small fragments to decrease the probability of long-distance dispersal events from small patches. These findings emphasize the importance of foraging style for seed dispersal and highlight the primacy of habitat size relative to spatial configuration in preserving biotic interactions
Bone Mineral Density in Healthy Female Adolescents According to Age, Bone Age and Pubertal Breast Stage
This study was designed to evaluate bone mineral density (BMD) in healthy female Brazilian adolescents in five groups looking at chronological age, bone age, and pubertal breast stage, and determining BMD behavior for each classification. Seventy-two healthy female adolescents aged between 10 to 20 incomplete years were divided into five groups and evaluated for calcium intake, weight, height, body mass index (BMI), pubertal breast stage, bone age, and BMD. Bone mass was measured by bone densitometry (DXA) in lumbar spine and proximal femur regions, and the total body. BMI was estimated by Quetelet index. Breast development was assessed by Tanner's criteria and skeletal maturity by bone age. BMD comparison according to chronologic and bone age, and breast development were analyzed by Anova, with Scheffe's test used to find significant differences between groups at P≤0.05. BMD (g·cm(-2)) increased in all studied regions as age advanced, indicating differences from the ages of 13 to 14 years. This group differed to the 10 and 11 to 12 years old groups for lumbar spine BMD (0.865±0.127 vs 0.672±0.082 and 0.689±0.083, respectively) and in girls at pubertal development stage B3, lumbar spine BMD differed from B5 (0.709±0.073 vs 0.936±0.130) and whole body BMD differed from B4 and B5 (0.867±0.056 vs 0.977±0.086 and 1.040±0.080, respectively). Bone mineralization increased in the B3 breast maturity group, and the critical years for bone mass acquisition were between 13 and 14 years of age for all sites evaluated by densitometry
Avaliação dos métodos de suscetibilidade antifúngica: Etest e macrodiluição em caldo para leveduras do gênero Candida isoladas da cavidade bucal de pacientes com AIDS
A comparison of the Etest and the reference broth macrodilution susceptibility test for fluconazole, ketoconazole, itraconazole and amphotericin B was performed with 59 of Candida species isolated from the oral cavities of AIDS patients. The Etest method was performed according to the manufacturer's instructions, and the reference method was performed according to National Committee for Clinical Laboratory Standards document M27-A guidelines. Our data showed that there was a good correlation between the MICs obtained by the Etest and broth dilution methods. When only the MIC results at ± 2 dilutions for both methods were considered, the agreement rates were 90.4% for itraconazole, ketoconazole and amphotericin B and 84.6% for fluconazole of the C. albicans tested. In contrast, to the reference method, the Etest method classified as susceptible three fluconazole-resistant isolates and one itraconazole-resistant isolate, representing four very major errors. These results indicate that Etest could be considered useful for antifungal sensitivity evaluation of yeasts in clinical laboratories.Foram comparados dois testes de suscetibilidade in vitro, macrodiluição em caldo e Etest através da determinação das concentrações inibitórias mínimas de fluconazol, cetoconazol, itraconazol e anfotericina B para 59 isolados de Candida obtidos da cavidade bucal de pacientes com AIDS. O método de Etest foi feito de acordo com as instruções do fabricante e o método de macrodiluição em caldo foi realizado seguindo as normas do NCCLS (National Committee for Clinical Laboratoratory Standards), documento M27-A, considerado método de referência. Nossos dados mostraram uma boa correlação entre os valores de concentração inibitória mínima encontrados para o Etest e o método de macrodiluição em caldo. Foi verificada concordância entre os resultados de CIM, de 90,4% para itraconazol, cetoconazol e anfotericina B e de 84,6% para fluconazol, quando se analisou isolados de C. albicans. A comparação de breakpoints mostrou que havia quatro grandes discrepâncias de resultados entre os dois métodos, sendo que pelo método de referência três isolados de Candida albicans classificados como resistentes ao fluconazol e um de C. krusei considerado resistente ao itraconazol foram sensíveis ao Etest. Estes resultados mostraram que o Etest é de grande valor nos testes de suscetibilidade antifúngica para leveduras do gênero Candida
The use of a task through virtual reality in cerebral palsy using two different interaction devices (concrete and abstract) - a cross-sectional randomized study.
BACKGROUND: Cerebral Palsy (CP) is characterised by variable difficulties in muscular action, resulting in inability of the individual to perform functional movement. An option to provide functionality to the individual with CP is the use of computer innovation. The aim of this paper was to verify if there was any performance improvement in a task performed in a virtual environment and if there was transfer to the task performed in the real environment and vice versa in this population. METHODS: A computer program was developed comprising a motor task, but with two possibilities of user interaction: a) concrete interface (with physical contact): in which the individual touches the computer screen to finish the task and b) abstract interface (no physical contact): in which the individual performs a hand movement in front of the Kinect device. Participants were split into two groups. The experimental group consisted of 28 individuals with CP within the ages of 6 and 15 years old. The control group included 28 typically developing individuals mirroring the age and sex of the experimental group. RESULTS: Individuals from both groups were able to improve task performance and retain acquired information. The CP group presented worse performance than the control group in all phases of the study. Further findings showed that the CP group presented better performance in the abstract interface than in the concrete interface, whereas, in the control group, the opposite occurred: their best performance was in the concrete. CONCLUSIONS: Motor tasks performed by individuals with CP through an interface with a more virtual environment feature (abstract interface: Kinect) provided better performance when compared to an interface with a more real characteristic (concrete interface: Touchscreen). TRIAL REGISTRATION: ClinicalTrials.gov Identifier - NCT03352440; Date of registration - November 17, 2017
Bartolosides E-K from a Marine coccoid cyanobacterium
The glycosylated and halogenated dialkylresorcinol (DAR) compounds bartolosides A-D (1-4) were recently discovered from marine cyanobacteria and represent a novel family of glycolipids, encoded by the brt biosynthetic gene cluster. Here, we report the isolation and NMR- and MS-based structure elucidation of monoglycosylated bartolosides E-K (5-11), obtained from Synechocystis salina LEGE 06099, a strain closely related to the cyanobacterium that produces the diglycosylated 2-4. In addition, a genome region containing orthologues of brt genes was identified in this cyanobacterium. Interestingly, the major bartoloside in S. salina LEGE 06099 was 1 (above 0.5% dry wt), originally isolated from the phylogenetically distant filamentous cyanobacterium Nodosilinea sp. LEGE 06102. Compounds 5-11 are analogues of 1, with different alkyl chain lengths or halogenation patterns. Their structures and the organization of the brt genes suggest that the DAR-forming ketosynthase BrtD can generate structural diversity by accepting fatty acyl-derived substrates of varying length. Compound 9 features a rare midchain gem-dichloro moiety, indicating that the putative halogenase BrtJ is able to act twice on the same midchain carbon. © 2016 The American Chemical Society and American Society of Pharmacognosy.We would like to thank CEMUP for NMR and HRMS analyses, I. Dias, A. Kijoa, and S. Buttachon for optical rotation measurements, and B. Jarrais for IR measurements. This work was supported by Fundação para a Ciência e a Tecnologia (FCT) through grants PTDC/MAR-BIO/2818/2012 and IF/01358/2014 to P.N.L. and partially by project NOVELMAR (NORTE-01-0145-FEDER-000035) supported by the NORTE2020 Program and the European Regional Development Fund
- …