99 resultados para Spectroscopy and microscopy characterization
Resumo:
Four formulations of mixed açaí (Euterpe oleracea) (A) and cocoa´s honey (Theobroma cacao) (CH) jellies were prepared according to the following proportions: T1 (40% A:60% CH), T2 (50% A:50% CH), T3 (60% A: 40% CH) and T4 (100% A - control). All formulations were prepared using a rate 60:40 (w/w) of sucrose and pulp, plus 0.5% pectin and the products reached to average of 65% soluble solids content. The jellies were analyzed by chemical and physicochemical (titratable acidity, pH, soluble solid content, dry matter, total protein, lipids, vitamin C and calories) and sensory characteristics; also were evaluated levels of P, K, Ca, Mg, Fe, Zn, Cu and Mn. It was used a hedonic scale of 7 points to evaluate the attributes: overall impression, spreadability, brightness, flavor, texture and color, and also was verified the purchase intention score. The titratable acidity and pH ranged from 0.46 to 0.64% and 3.35 to 3.64, respectively, that are within the range found at most fruit jellies. The soluble solids content ranged between 65.2 and 65.5 ºBrix. The sensory acceptance results showed that all treatments (T1, T2, T3 and T4) presented means of sensory attributes above 4, demonstrating good acceptance of the product, but the treatment T1 presented the higher scores for the evaluated attributes. Cocoa´s honey added a positive influence on the attributes of color, texture and spreadability.
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The aim of this work is to obtain, purify and characterize biochemically a peroxidase from Copaifera langsdorffii leaves (COP). COP was obtained by acetone precipitation followed by ion-exchange chromatography. Purification yielded 3.5% of peroxidase with the purification factor of 46.86. The COP optimum pH is 6.0 and the temperature is 35 ºC. COP was stable in the pH range of 4.5 to 9.3 and at temperatures below 50.0 ºC. The apparent Michaelis-Menten constants (Km) for guaiacol and H2O2 were 0.04 mM and 0.39 mM respectively. Enzyme turnover was 0.075 s-1 for guaiacol and 0.28 s-1 for hydrogen peroxide. Copaifera langsdorffii leaves showed to be a rich source of active peroxidase (COP) during the whole year. COP could replace HRP, the most used peroxidase, in analytical determinations and treatment of industrial effluents at low cost.
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The influence of drug concentration, oil phase, and surfactants on the characteristics of dexamethasone-loaded nanocapsules was investigated. The best formulations were obtained at dexamethasone concentrations of 0.25 and 0.50 mg.mL-1 (encapsulation efficiency: 80-90%; mean size: 189-253 nm). The type of oil phase influenced only the stability of dexamethasone-loaded nanocapsules. The association of polysorbate 80 and sorbitan monooleate provided a more stable formulation. Sunflower oil and sorbitan sesquioleate used for the first time as oil phase and surfactant for nanocapsules, respectively, have allowed obtaining suspensions with low mean size and narrow size distribution.
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It was investigated Au(I)-sulfite baths containing formaldehyde. As a result, high stability was achieved for baths containing formaldehyde concentration close to 10 mL L-1 with a lifetime superior to 600 days. On the other hand, cyclic voltammograms indicated that the increase of formaldehyde concentration in the bath promotes decreasing of the maximum cathodic current, so that, if the formaldehyde concentration is high, the surface areal concentration of gold will be low. Also, the lowest surface roughness was obtained for 10 mL L-1 of formaldehyde.
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We propose an analytical method based on fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy to detect the adulteration of petrodiesel and petrodiesel/palm biodiesel blends with African crude palm oil. The infrared spectral fingerprints from the sample analysis were used to perform principal components analysis (PCA) and to construct a prediction model using partial least squares (PLS) regression. The PCA results separated the samples into three groups, allowing identification of those subjected to adulteration with palm oil. The obtained model shows a good predictive capacity for determining the concentration of palm oil in petrodiesel/biodiesel blends. Advantages of the proposed method include cost-effectiveness and speed; it is also environmentally friendly.
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Turnera subulata Sm., known as "Chanana" or "flor-do-Guarujá" in Brazilian folklore, is a plant species belonging to the subfamily Turneroideae of family Passifloraceae, which is used for various medicinal purposes in Brazil. The phytochemical study conducted here led to the isolation and identification of ten compounds present in T. subulata: two mixtures of steroids, sitosterol and stigmasterol (nonglycosylated and glycosylated); a mixture of flavonoids, 5,7,4′-trihidroxiflavona-8-C-α-glucopyranoside and 5,7,3′,4′-tetrahidroxiflavona-8-C-α-glucopyranosidel; and four phaeophytins, phaeophytin purpurin-18-phytyl ester, a rare natural product, phaeophytin a , 13²-hydroxy-(13²-S)-phaeophytin a , and phaeophytin b Phaeophytin b exhibited electrochemical activity similar to that of phthalocyanines.
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This work shows the application of ¹H NMR spectroscopy and chemometrics for quality control of grape juice. A wide range of quality assurance parameters were assessed by single ¹H NMR experiments acquired directly from juice. The investigation revealed that conditions and time of storage should be revised and indicated on all labels. The sterilization process of homemade grape juices was efficient, making it possible to store them for long periods without additives. Furthermore, chemometric analysis classified the best commercial grape juices to be similar to homemade grape juices, indicating that this approach can be used to determine the authenticity after adulteration.
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The cubiu (Solanum sessiliflorum) fruit, originating in the Amazon basin, is commonly used in that region for food, medicine, and cosmetics. In an experimental culture of cubiu, in order to evaluate its adaptation to conditions in the Northern region of the state of Rio de Janeiro, it was observed plants with mosaic symptoms. A cubiu plant was collected and analyzed to identify the etiological agent. After mechanical passage through a local lesion host, a host range test was performed. The virus induced chlorotic local lesions in Chenopodium quinoa, necrotic local lesions in Gomphrena globosa, mosaic in S. sessiliflorum, leaf and stem necrosis in tomato (Lycopersicon esculentum) 'Rutgers', mosaic and leaf distortion in Datura stramonium and Physalis floridana, and necrotic local lesions followed by systemic necrosis and plant death in four Nicotiana species. Electron microscopic observations of ultra thin sections from infected cubiu leaves showed the presence of spheroidal, membrane-bound particles typical of tospovirus species. Analysis of the nucleocapsid protein from concentrated virus particles indicated the presence of a 28 kDa protein. RT-PCR was performed after total RNA extraction from infected IPA-6 tomato leaves. A fragment of approximately 0,8 kbp corresponding to the N gene was amplified, cloned and sequenced. The N protein from the cubiu isolate was 95% homologous to the Groundnut ringspot virus (GRSV) protein, and no more than 85% homologous to those from Zucchini lethal chlorosis virus (ZLCV) and Chrysanthemun stem necrosis virus (CSNV), Tomato spotted wilt virus (TSWV), and Tomato chlorotic spot virus (TCSV). This is the first report of the occurrence of GRSV (or any other plant virus) in cubiu.
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An epidemic of rice (Oryza sativa) blast occurred on cultivars Epagri 108 and 109 in the municipalities of Lagoa da Confusão and Duerê in the State of Tocantins, during the rice-growing season 1998-99. DNA fingerprinting and virulence phenotype analysis were utilized to determine the diversity of Pyricularia grisea isolates collected from these cultivars in one epidemic year. Rep-PCR analysis of isolates was done by using two primer sequences from Pot2. Two distinct fingerprint groups or lineages were identified among 53 isolates collected from nine different commercial fields. The virulence pattern of isolates retrieved from these two cultivars was analyzed in artificial inoculation tests utilizing 32 genotypes in the greenhouse. A dendrogram constructed from virulence phenotype data showed a single group considering 77% similarity level. The predominant pathotype IB-45 was represented by 47 of the 53 isolates corresponding to 83%. Four other pathotypes (IB-1, IB-9, IB-13 and IB-41) were identified at random among the isolates from these cultivars. There was no relation between rep-PCR grouping and pathotypes. The results showed that the isolates of P. grisea recovered from cultivars Epagri108 and 109 in farmers' fields had narrow phenotypic and genetic diversity. The blast outbreak on these two cultivars one year after their introduction could be attributed to the new pathotype IB-45 or its increase, which was hitherto existing in low frequency.
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The complex permittivity of films of polyether ether ketone (PEEK) has been investigated over a wide range of frequency. There is no relaxation peak in the range of 1Hz to 10(5) Hz but in the low-frequency side (10-4 Hz) there is an evidence of a peak that also can be observed by thermally stimulated discharge current measurements. That peak is related with the glass transition temperature (Tg) of the polymer. The activation energy of the relaxation was found to be 0.44 eV, similar to that of several synthetic polymers. Space charges are important in the conduction mechanism as shown by discharging transient.
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This work reports on the investigation of nanosized CeO2-ZnO systems prepared by Pechini's method. The structural and morphological characterization of CeO2-ZnO systems as well as the characterization of CeO2 and ZnO separately, showed that the employed method result in powders with spheroidal particles whose size are in the range 30 - 200 nm, which is appropriate to provide homogeneous suspensions. The ZnO present in the prepared mixed oxides seems to increase particle size distribution and to influence the arrangement of the particles after powder dispersion.
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Physiological and biochemical aspects of assai palm during seed germination and early seedling growth were investigated. Seeds collected from plants growing in flooded and upland forests were used to determine the influence of normoxic (aerobic) and anoxic (anaerobic) conditions in germination and the initial and average time of development in the roots and shoots. After 75 days, seedlings germinated under normoxia were transferred to trays and submitted to flooding. Seed reserves (lipids, proteins, soluble sugars and starch) were monitored for quiescent and germinated seeds maintained under normoxic and anoxic conditions, as well as after 5, 10 and 20 days of seedling growth. Alcohol dehydrogenase (ADH) activity was quantified in roots and leaves of seedlings without or with flooding (partial and total). Seeds were not able to germinate under anoxia. Different strategies of storage mobilization of lipids, proteins, soluble sugars and starch were observed in seeds of each environment. ADH activity was induced by anoxia, with the highest level observed in the leaves. This study showed that, under normoxic conditions, the best developmental performance of assai palm seeds, from flooded or upland forest areas, during germination was associated with primary metabolites mobilization and seedling flooding tolerance with increased ADH activity. We conclude that the assai palm is well adapted to the anoxic conditions provoked by flooding.
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ABSTRACT In Brazil, specifically in São Paulo State, there are guidelines based on the high diversity of tropical forests that instructs the restoration projects in the state (current SMA 32/2014). The main goal of this study was verify the importance and effectiveness of the high diversity of arboreal species originated from a reforestation, and its influence in a woody regenerating composition. We developed a phytosociologic study in a woody regenerating stratum of a nine year old reforestation at a Private Reserve of Natural Heritage (RPPN), in Mogi-Guaçu, São Paulo State. All specimens with height > 30 cm and Diameter at Breast Height (DBH) < 5 cm were evaluated. The woody regenerating diversity was smaller than the overstory diversity and the species composition was similar to the overstory. The Simpson index (1-D) was 0.85, Shannon index (H') was 2.46 and the Pielou index (J') was 0.60. The zoochoric dispersion syndrome was major among the species. Our results suggest that the use of high diversity of native seedlings in a reforestation leads to high diversity of species in woody regeneration stratum, after one decade of planting.
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A retrospective study of 24 cases of papillomas in dogs was performed from January 2001 to March 2011. Additionally, immunohistochemistry (IHC) was used to characterize and evaluate the samples. We found that disease was observed more in mixed breed dogs, ages ranging from 6 months to 10 years (mean 3.1 years), and there was no gender predilection. The main lesion sites were the skin (75%), lips (16.7%), and eyelids (8.3%). Upon histological evaluation, we observed papillary exophytic proliferation of squamous epithelium and papillary endophytic proliferation (inverted) in 87.5% and 12.5% of cases, respectively. The tumors were characterized by spinous layer hyperplasia (87.5%) with koilocytes (70.8%) and intranuclear pale basophilic inclusions bodies (8.3%), prominent granular layer with large amounts of keratohyalin granules (95.8%), and hyperkeratosis in the stratum corneum (100%). Positive immunostaining for Papillomavirus was found in 83.3% of cases, which were distributed between the granular layer and the stratum corneum. These findings indicate the following: that papillomas in dogs are caused by Papillomavirus, the viral cytopathic effect induces epithelial lesions, viral particles are found inside the cell nuclei, and inclusions bodies are rare.