Entity

Time filter

Source Type


Paiva E.A.S.,Federal University of Minas Gerais | Martins L.C.,Instituto Federal Of Educacao Ciencia E Tecnologia Do Sul Of Minas Gerais
Plant Biology | Year: 2014

Nectaries occur widely in Convolvulaceae. These structures remain little studied despite their possible importance in plant-animal interactions. In this paper, we sought to describe the structure and ultrastructure of the receptacular nectaries (RNs) of Ipomoea cairica, together with the dynamics of nectar secretion. Samples of floral buds, flowers at anthesis and immature fruits were collected, fixed and processed using routine methods for light, scanning and transmission electron microscopy. Circadian starch dynamics were determined through starch measurements on nectary sections. The secretion samples were subjected to thin layer chromatography. RNs of I. cairica were cryptic, having patches of nectar-secreting trichomes, subglandular parenchyma cells and thick-walled cells delimiting the nectary aperture. The glandular trichomes were peltate type and had typical ultrastructural features related to nectar secretion. The nectar is composed of sucrose, fructose and glucose. Nectar secretion was observed in young floral buds and continued as the flower developed, lasting until the fruit matured. The starch content of the subglandular tissue showed circadian variation, increasing during the day and decreasing at night. The plastids were distinct in different portions of the nectary. The continuous day-night secretory pattern of the RNs of I. cairica is associated with pre-nectar source circadian changes in which the starch acts as a buffer, ensuring uninterrupted nectar secretion. This circadian variation may be present in other extrafloral nectaries and be responsible for full daytime secretion. We conclude that sampling time is relevant in ultrastructural studies of dynamic extranuptial nectaries that undergo various changes throughout the day. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands. Source


Bautitz I.R.,Sao Paulo State University | Bautitz I.R.,Federal University of Parana | Velosa A.C.,Sao Paulo State University | Velosa A.C.,Instituto Federal Of Educacao Ciencia E Tecnologia Do Sul Of Minas Gerais | Nogueira R.F.P.,Sao Paulo State University
Chemosphere | Year: 2012

Parameters that influence the zero valent iron mediated degradation of the pharmaceutical diazepam (DZP) were evaluated including the iron concentration and its pre-treatment, the effect of complexation with EDTA and oxic versus anoxic condition. It was observed that acid pre-treatment of iron particles is important for degradation efficiency and that H 2SO 4 is a better choice than HCl, resulting in higher degradation of DZP. Under oxic conditions, the degradation of DZP achieved 96% after 60min using Fe 0 (25gL -1) pre-treated with H 2SO 4 in the presence of EDTA (119mgL -1), while mineralization achieved around 60% after the same time. Under anoxic conditions, degradation occurred, however at lower extent, achieving 67% after 120min. The addition of EDTA improved the treatment efficiency in 20% leading to 99% DZP degradation after 120min. The first intermediates formed during DZP degradation were identified using LC/MS analysis and revealed the formation of mono- and di-hydroxylated products from DZP during Fe 0/EDTA/O 2 degradation, which evidences that OH was the main oxidizing species formed in this process. © 2012 Elsevier Ltd. Source


Dos Santos Farias E.,Federal University of Acre | Dos Santos A.P.,Federal University of Acre | De Farias-Junior J.C.,University of Campinas | Ferreira C.R.T.,Federal University of Acre | And 3 more authors.
Revista de Nutricao | Year: 2012

Objective This study verified the prevalence of excess weight and associated factors in adolescents from private schools in Rio Branco, Acre, Brazil. Methods This cross-sectional study included 741 adolescents from private schools in Rio Branco, Acre. The following data were collected: sex, age, socioeconomic status, parents' education level, number of people in the household, number of siblings, level of physical activity, and number of hours spent daily watching television and using a computer. Logistic regression was used to investigate possible relationships between excess weight and associated factors. Results The general prevalence of excess weight was 26.9% (30.0% for males and 24.2% for females). Inactive (OR=2.75) males (OR=1.34) from the upper middle class (OR=2.06) or upper class (OR=2.36) were at highest risk of excess weight. Conclusion Inactive male adolescents belonging to the upper middle and upper classes are at high risk of excess weight in this region of Brazil. Source


Bouzzine S.M.,Regional Center for Trades and Professional Education | Bouzzine S.M.,Moulay Ismai University | Salgado-Moran G.,Andres Bello University | Hamidi M.,Moulay Ismai University | And 3 more authors.
Journal of Chemistry | Year: 2015

Polythiophene (PTh) and its derivatives are polymer-based materials with a π-conjugation framework. PTh is a useful photoelectric material and can be used in organic semiconductor devices, such as PLED, OLED, and solar cells. Their properties are based on molecular structure; the derivatives contain different substitutes in the 3 and 5 positions, such as electron-donating or electron-withdrawing groups. All molecular geometries were optimized at B3LYP/6-31G(d,p) level of theory. The energy gap (Egap) between the HOMO and LUMO levels is related to the π-conjugation in the PTh polymer backbone. In this study, the DFT calculations were performed for the nonsubstituted and 3,5-substituted variants to investigate the stability geometries and electrical properties. The theoretical calculations show that the substituted forms are stable, have low Egap, and are in good agreement with the experimental observations. © 2015 Si. Mohamed Bouzzine et al. Source


The project goal is to evaluate the silvicultural development and the survival of species in differentseedlings planting models for the recovery of the landfill area in Inconfidentes – South of Minas Gerais/Brazil, which shows lack of vegetation, causing visual and environmental impact. This paper also aims to suggest different species that may be used on the requalification of landfills. This experiment was installed in a completely randomized statistic design with four plantation models and seedlings of 11 native tree species and also a grass species, Chrysopogon zizanioides (M1-Legume; M2-Legume + Chrysopogon zizanioides; M3-native and M4-Eremanthus erytropappus and Nectandra lanceolata) and three repetitions. The plots of 3 x 5 m of each treatment were composed by 15 tree seedlings and on each M2 planting model eight seedlings of the Vetiver grass (C. Zizanioides) were added. During 20 months the height of those plants, the trunk diameter on soil level, the canopy area and survival were evaluated in gaps of 30 days. The data about the silvicultural growth and survival among those treatments and among species were submitted to variance analysis and the mean values were compared by the Scott Knott test at a 5% probability. Based on the results of the recovery of the inactivated landfill area in Inconfidentes – South Minas Gerais/Brazil, it is possible to conclude that the plantation model M2 and the species Bauhinia forficate, Eritrina falcate, Senna multijuga, Schizolobium parahyba and Schinus terebinthifolius are the most indicated species for that area recovery. © 2015, Sociedade de Investigacoes Florestais. All rights reserved. Source

Discover hidden collaborations