alpha-SiAlON ceramics with elongated grain morphology using an alternative sintering additive

In this work, the use of a natural yttrium oxide and rare earth oxide solid solution (CRE2O3) as stabilizers of the alpha-Si3N4 phase to form alpha-SiAlON has been investigated. This oxide mix is produced at FAENQUIL-DEMAR, at a cost of only 20% of pure commercial Y2O3. Two alpha-SiAlONs using pure Y2O3 or CRE2O3 have been prepared, using mixes of 20% by volume of a molar fraction of 9:1 of AlN to Y2O3 or AlN to CRE2O3, respectively, with 80% alpha-Si3N4. Samples were gas pressure-sintered at 1900 degreesC, under 1.5 MPa of N-2 for 60 min. Both compositions yielded alpha-SiAlON ceramics with high relative densities (98% t.d.), hardness of 18 GPa and fracture toughness of 5 Mpa m(1/2), with homogeneous microstructures composed of elongated alpha-SiAlON grains with aspect ratios of 5. It is concluded that the mixed rare earth concentrate (CRE2O3) can be used to produce alpha-SiAlON ceramics with similar microstructures and mechanical properties of alpha-SiAlON ceramics fabricated using pure Y2O3, but with the advantage of its lower production cost. (C) 2004 Elsevier B.V All rights reserved.

Evaluation of the microscopic observation drug susceptibility assay for detection of Mycobacterium tuberculosis resistance to pyrazinamide

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of the microvascular density in astrocytomas in adults correlated using SPECT-MIBI

Microvascular density (MVD) may be an additional prognostic marker for astrocytomas, but the heterogeneity of these tumors limits its use. Thus, imaging examinations such as SPECT-MIBI (2-methoxyisobutyl isonitrile) may take on an indirect role in astrocytoma evaluation. The aim of this study was to evaluate MVD in astrocytomas using immunohistochemistry with anti-CD34 monoclonal antibodies. The relationship between the immunohistochemical data and the parameters obtained from SPECT-MIBI was evaluated. This cross-sectional study evaluated 48 patients with brain tumors including low-grade astrocytomas (LGAs), anaplastic astrocytomas (AAs) and glioblastoma multiformes (GBMs). Patients had been admitted to the Hospital de Cancer de Barretos - Fundação Pio XII, and underwent brain SPECT-MIBI prior to any treatment. MVD was determined under an optical microscope by counting microvessels on slides from each case. SPECT-MIBI images were analyzed visually and semiquantitatively. GBMs, AAs and LGAs represented 50, 16.7 and 33.3% of the total sample, respectively. There were 13 normal and 35 abnormal SPECT-MIBI images. Significant differences in MVD were found between AA and LGA cases (p=0.040), but not between normal and abnormal SPECT-MIBI. The mean counts from SPECT-MIBI were not correlated with MVD. Among the GBM cases, there were no significant findings, except for an increased likelihood of abnormal histological test results. MVD was related to histological grade (in AA and LGA cases) but was not correlated with SPECT-MIBI.

A metodologia de superfície de resposta como ferramenta para a avaliação da produção de alginato e poli-hidroxibutirato pela Azotobacter vinelandii

The response surface methodology as a tool for assessing the production of alginate and polyhydroxybutirate by Azotobacter vinelandii. Alginate is a polysaccharide extracted from cell walls of brown algae and used in the food, pharmaceuticals and biotech industries. Production is concentrated on the cultivation of brown seaweed, but several bacteria of the genus Pseudomonas and Azotobacter produce alginate. The chemical structure of alginates produced by algae is similar to those synthesized by A. vinelandii. The bacteria also produce intracellular polymers such as polyhydroxybutyrate (PHB), known as bioplastic. This work studied the simultaneous alginate and PHB production by A. vinelandii using sucrose and different parameters of fermentation in an orbital shaker. The optimal values for the production of these compounds were determined by the MSR. The first experiment was a 2(6-2) factorial design. The second was based on significant variables of the first, resulting in a full 3(3-0) factorial design. From the first to the second, an increase was observed in the PHB productivity from 12 to 45 mg g(-1) cell h(-1) and alginate from 100 to 1,600 mg g(-1) of cell h(-1). The productivity of both compounds was in the maximum incubation temperature of 62 degrees C, in the shortest time of incubation (18h) and the sucrose concentration, 11 g L(-1). In both experiments the PHB extracted presented purity of 94%.

Open and standardized tools for smart transducer networking

IEEE 1451 Standard is intended to address the smart transducer interfacing problematic in network environments. Usually, proprietary hardware and software is a very efficient solution to in planent the IEEE 1451 normative, although can be expensive and inflexible. In contrast, the use of open and standardized tools for implementing the IEEE 1451 normative is proposed in this paper. Tools such as Java and Phyton programming languages, Linux, programmable logic technology, Personal Computer resources and Ethernet architecture were integrated in order to constructa network node based on the IEEE 1451 standards. The node can be applied in systems based on the client-server communication model The evaluation of the employed tools and expermental results are presented. © 2005 IEEE.

La planificación para el desarrollo y los instrumentos reales de acción gubernamental

Publicado como documento INST/S.9/L.12

Necesidades de bienes y servicios ambientales en las micro y pequeñas empresas: el caso mexicano

Incluye Bibliografía

Flying geese or sitting ducks? Transnationals and industry in developing countries

Includes bibliography

Industrial policy: where do we stand?

Includes bibliography

The challenge of industrial competitiveness

Includes bibliography

Rural society: its integration and disintegration

Includes bibliography

Indigenous peoples and modernity

Includes bibliography

Women: productivity and labour in the United States

Includes bibliography

Capital flows and their effect on the monetary base

Includes bibliography