Compact Ag@fe3o4 Core-shell Nanoparticles By Means Of Single-step Thermal Decomposition Reaction.

A temperature pause introduced in a simple single-step thermal decomposition of iron, with the presence of silver seeds formed in the same reaction mixture, gives rise to novel compact heterostructures: brick-like Ag@Fe3O4 core-shell nanoparticles. This novel method is relatively easy to implement, and could contribute to overcome the challenge of obtaining a multifunctional heteroparticle in which a noble metal is surrounded by magnetite. Structural analyses of the samples show 4 nm silver nanoparticles wrapped within compact cubic external structures of Fe oxide, with curious rectangular shape. The magnetic properties indicate a near superparamagnetic like behavior with a weak hysteresis at room temperature. The value of the anisotropy involved makes these particles candidates to potential applications in nanomedicine.

Mapeamento de semeaduras de soja (Glycine max (L.)Merr.) mediante dados MODIS/Terra E TM/Landsat 5: um comparativo

The objective of this work was to compare the soybean crop mapping in the western of Parana State by MODIS/Terra and TM/Landsat 5 images. Firstly, it was generated a soybean crop mask using six TM images covering the crop season, which was used as a reference. The images were submitted to Parallelepiped and Maximum Likelihood digital classification algorithms, followed by visual inspection. Four MODIS images, covering the vegetative peak, were classified using the Parallelepiped method. The quality assessment of MODIS and TM classification was carried out through an Error Matrix, considering 100 sample points between soybean or not soybean, randomly allocated in each of the eight municipalities within the study area. The results showed that both the Overall Classification (OC) and the Kappa Index (KI) have produced values ranging from 0.55 to 0.80, considered good to very good performances, either in TM or MODIS images. When OC and KI, from both sensors were compared, it wasn't found no statistical difference between them. The soybean mapping, using MODIS, has produced 70% of reliance in terms of users. The main conclusion is that the mapping of soybean by MODIS is feasible, with the advantage to have better temporal resolution than Landsat, and to be available on the internet, free of charge.

Efeito de baixas doses de radiação X em feridas suturadas e não suturadas - estudo experimental em ratos

The present work evaluated the effect of low doses of X-irradiation on the repairing process of sutured and nonsutured skin wounds in rats. For that, rats underwent a surgical proceedure, in which a 20 x 5-millimeter rectangular wound approximately 2-millimeter-deep was made in the dorsal region of each animal, and were divided in four groups: nonirradiated nonsutured; irradiated nonsutured ; nonirradiated sutured and irradiated sutured. The animals under irradiation were protected, during exposure, with a 2-millimeter-thick lead apron in such a way that only the incision was irradiated. Each animal was submitted to 18 seconds of exposure, undergoing a total of 7.4 rads. The evaluation of the effects of X-rays on the repairing process was carried out through microscopic observation by means of hematoxylin-eosin staining for morphological evaluation, and silver impregnation under polarized light for the observation of collagen synthesis. The results have shown that X-irradiation has caused delay in the repairing process, but it did not stop its development. The irradiated nonsutured group was considered to show the greater delay when compared with the other groups.

Determinação do máximo déficit acumulado de oxigênio: efeito da duração dos testes submáximos para predição da demanda de oxigênio

The aim of this study was to investigate the influence of different assessment time periods of submaximal tests on the determination of the maximal accumulated oxygen deficit (MAOD), through the adoption of different time slots of 4 to 6, 6 to 8 and 8 to 10 min. Ten cyclists with mean age of 27.5 ± 4.1 years, body mass 74.4 ± 12.7 kg and time experience of 9.8 ± 4.7 years participated in this study. The athletes underwent an incremental exercise test to determine the peak oxygen consumption (VO2peak), and four submaximal constant work-load test sessions (60, 70, 80 and 90% VO2peak) of 10 min in order to estimate the O2 demand (DEO2). The mean VO2 values obtained on each constant work-load for the 4 to 6, 6 to 8 and 8 to 10 min time-periods intervals were used to perform a linear regression between the intensity and O2 consumption for each time-period. In addition, the subjects performed one supramaximal rectangular test (110% VO2peak) for the quantification of MAOD. There was no significant difference in VO2 between the different time-periods for all submaximal tests (P> 0.05). Similarly, no significant difference was found in DEAO2 and MAOD (P> 0.05). Furthermore, the values of MAOD for the three time-periods intervals showed good agreement and strong correlation. Thus, the data suggest that the submaximal tests used to estimate the values of MAOD can be reduced, at least in this type of sample, and with the use of a cycle simulator.

The Sperm Of Hexagenia (pseudeatonica) Albivitta Walker (ephemeroptera: Fossoriae: Ephemeridae)

This study describes the sperm morphology of the mayfly Hexagenia (Pseudeatonica) albivitta (Ephemeroptera). Its spermatozoon measures approximately 30 μm of which 9 μm corresponds to the head. The head is composed of an approximately round acrosomal vesicle and a cylindrical nucleus. The nucleus has two concavities, one in the anterior tip, where the acrosomal vesicle is inserted and a deeper one at its base, where the flagellum components are inserted. The flagellum is composed of an axoneme, a mitochondrion and a dense rod adjacent to the mitochondrion. A centriolar adjunct is also observed surrounding the axoneme in the initial portion of the flagellum and extends along the flagellum for at least 2 μm, surrounding the axoneme in a half-moon shape. The axoneme is the longest component of the flagellum, and it follows the 9+9+0 pattern, with no central pair of microtubules. At the posterior region of the flagellum, the mitochondrion has a dumb-bell shape in cross sections that, together with the rectangular mitochondrial-associated rod, is responsible for the flattened shape of the flagellum. An internal membrane is observed surrounding both mitochondrion and its associated structure.