ABSTRACT
The main characteristic of materials with a functional gradient is the progressive composition or the structure variation across its geometry. This results in the properties variation in one or more specific directions, according to the functional application requirements. Cellular structure flexibility in tailoring properties is employed frequently to design functionally-graded materials. Topology optimisation methods are powerful tools to functionally graded materials design with cellular structure geometry, although continuity between adjacent unit-cells in gradient directions remains a restriction. It is mandatory to attain a manufacturable part to guarantee the connectedness between adjoining microstructures, namely by ensuring that the solid regions on the microstructure's borders i.e., kinematic connectors) match the neighboring cells that share the same boundary. This study assesses the kinematic connectors generated by imposing local density restrictions in the initial design domain (i.e., nucleation) between topologically optimised representative unit-cells. Several kinematic connector examples are presented for two representatives unit-cells topology optimised for maximum bulk and shear moduli with different volume fractions restrictions and graduated Young's modulus. Experimental mechanical tests (compression) were performed, and comparison studies were carried out between experimental and numerical Young's modulus. The results for the single maximum bulk for the mean values for experimental compressive Young's modulus (Ex¯) with 60%Vf show a deviation of 9.15%. The single maximum shear for the experimental compressive Young's modulus mean values (Ex¯) with 60%Vf, exhibit a deviation of 11.73%. For graded structures, the experimental mean values of compressive Young's moduli (Ex¯), compared with predicted total Young's moduli (ESe), show a deviation of 6.96 for the bulk graded structure. The main results show that the single type representative unit-cell experimental Young's modulus with higher volume fraction presents a minor deviation compared with homogenized data. Both (i.e., bulk and shear moduli) graded microstructures show continuity between adjacent cells. The proposed method proved to be suitable for generating kinematic connections for the design of shear and bulk graduated microstructured materials.
ABSTRACT
The electrophoretic fractionation represents one of the most reliable methods for the identification of blood proteins in ruminants. The aim of this study was to evaluate the serum proteinogram of sheep with acute ruminal lactic acidosis (ARA) using the SDS-PAGE electrophoresis technique. Ten Santa Inês ewes were used and blood was collected to establish the basal values for induction of ARA. Sucrose was administered orally in a single dose of 15 g/kg body mass. After the administration, blood samples were obtained at the following moments: 4, 8, 12, 16, 20, 24, 28, 32, 36, 48, 72, 96, 120 and 144 h. Subsequently, samples were obtained every seven days for three further weeks, until complete one month. The total of 13 proteins were identified: immunoglobulins A and G, ceruloplasmin, transferrin, albumin, α1-antitrypsin, haptoglobin, α1-acid glycoprotein, proteins of molecular weight 95, 46, 36 and 31 kDa. The increase of haptoglobin from 08 h coincides with the ruminal pH decrease, possibly due to the death of Gram negative bacteria and also the inflammatory process on the rumen. Fibrinogen was presented on highest mean at 48 h and returned to normal with 144 h. We can conclude that changes in serum levels of acute phase proteins can assist the clinical evaluation and diagnosis of ARA in sheep.
ABSTRACT
Northern South America presents a diverse array of nonforest or savanna-like ecosystems that are patchily distributed. The distribution of these open habitats has been quite dynamic during Quaternary glacial-interglacial cycles; yet, the relevance of climatically driven vicariance events to the diversification of nonforest Amazonian vertebrates remains poorly known. We analyzed karyologic and mitochondrial DNA sequence data of the genus Zygodontomys, a small cricetid rodent distributed throughout nonforest habitats of northern Amazonia. Samples analyzed represented 4 Brazilian Amazonian localities and 2 French Guiana localities. Karyologic variation among Amazonian Brazilian Zygodontomys populations is high, with, at least, 3 karyomorphotypes. Molecular phylogenetic analyses recovered 3 major clades congruent with known karyotypes, a finding that suggests the existence of 3 species, 2 of which currently undescribed. The French Guiana and Surumú clade, identified as Zygodontomys brevicauda microtinus, is characterized by 2n = 86 and is sister to the clade formed by the 2 nondescribed forms. The Rio Negro-Rio Branco form is characterized by 2n = 82, and the Ferreira Gomes-Itapoá form is characterized by 2n = 84. The distribution of the 3 Zygodontomys lineages identified is in accordance with the geography of the open vegetation patches in Northern Amazonia, and divergence time estimates relate speciation events to the middle-upper Pleistocene, supporting the prominent role of Quaternary climatically driven vicariance events in the diversification of the genus.
