Evaluation of Y2O3 as front layer of ceramic crucibles for vaccum induction melting of tial based alloys

During the last decades titanium alloys were found to be valuable engineering materials for many different applications. Formerly used in critical applications like aerospace, aeronautic and military equipment, where the factor cost is not relevant, titanium alloys are finding now new and different markets. However, the development of such new markets will depend on an effective cost reduction of titanium parts, in order to achieve a selling cost suitable with its application in consumer goods. A possible solution to decrease production costs might be the use of traditional casting techniques to produce near net shape functional parts. During the last years, the authors have developed extensive research work on this field, and a new technique both for melting and moulding, using ceramic multi-layered crucibles and investment casting shells was developed. This paper presents some of the results obtained during that research work: Ti-48Al alloy were melted and cooled inside CaO, MgO and Y2O3 stabilized ZrO2 crucibles with inside layer of Y2O3. The chemical composition, hardness and microstructure at the metal-crucible interface, studied by secondary ion mass spectrometry, SEM/EDS and XRS are presented. On a second step, the same alloy was melted on the same crucibles, and poured into graphite moulds, and the crucibles wall was characterized by SEM/EDS and XRS.(undefined

Availability of timber housing construction techniques in Brazil

Se analiza la representatividad de las viviendas hechas en madera, en Brasil, indicando el porcentaje de cada técnica constructiva según la oferta de las empresas evaluadas. Los porcentajes que evidencian la frecuencia de utilización de las técnicas de construcción en madera fueron medidos por medio de dos metodologías aplicadas en las empresas: encuesta por entrevistas personales a sus propietarios y búsqueda de datos en sus sitios web. El método de encuestas por entrevistas evaluó 107 empresas brasileñas, y el de búsqueda en los sitios web alcanzó 207 empresas; se consiguió 50,95 y 98,57 %, respectivamente, de la población estimada. A pesar de esta diferencia, ambos métodos demostraron un escenario similar. Las entrevistas presentaron mayores costos de aplicación. Las técnicas contemporáneas están disponibles en más del 90 % de los productores brasileros. Las casas de tablas horizontales clavadas y las casas de tablas horizontales entre pilares fueron las que tuvieron mayores ofertas.This paper analyzes the representativeness of timber housing in Brazil, identifying the percentage of construction techniques offered by each evaluated company. Percentages that evidence the frequency of use of wooden building techniques were measured using two methods applied in the companies: survey through face-to-face interviews with owners and data search on their websites. The survey through interviews evaluated 107 Brazilian companies, while the data search included 207 companies, obtaining 50.95% and 98.57% of the estimated population, respectively. In spite of this difference, both methods showed a similar scenario. Interviews evidenced higher application costs. Contemporary techniques are available in more than 90% of Brazilian constructors. Houses with nailed horizontal boards and houses with horizontal wooden boards between columns were offered the most

Effect of processing conditions on electromagnetic shielding and electrical resistivity of injection-molded polybutylene terephthalate compounds

This research introduces an analysis of the anisotropic electrical resistivity (ER) and its relation to the electromagnetic shielding effectiveness (EMSE) for two injection-molded carbon-fiber-reinforced polybutylene terephthalates (PBTs). The properties were measured for 2-mm thick injection moldings considering the effect of melt temperature, injection velocity, and flow distance. The results for one compound showed an EMSE in the range of 30–40 dB, while EMSE for a compound with lower filler content is in the range of 45–75 dB. A combination of higher temperature and higher velocity leads to an increase of EMSE for both compounds in the range of 3%–8.5%. However, the increase in flow path reduced the EMSE for both compounds up to 10%. A novel experimental apparatus was used to measure the anisotropic ER in the three directions, that is, parallel, perpendicular, and transversal to flow. It is evident that injection molding induced high anisotropy for both compound specimens, and, depending on the processing conditions, produced similar longitudinal resistivity (0.2–4 Ω.cm) but higher transversal resistivity (8–22 Ω.cm). ER properties were compared with EMSE, evidencing an inverse relation as expected. Furthermore, it was found that the longitudinal resistivity is the main contributor to the specimens shielding.The authors would like to acknowledge all the associates from University of Minho, Centre for Innovation in Polymer Engineering (PIEP and Bosch Car Multimedia who had an active part in the development of this research and acknowledge that this project, INNOVCAR, was supported by the European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Program (COMPETE 2020) [Project no 002797; Funding Reference: POCI-01-0247-FEDER-002797]

Characterization of TiAl alloys by secondary Ion mass spectrometry

Titanium aluminides are arising as a valuable alternative to superalloys in applications where the ratio resistance/density is important. Together with excellent mechanical and corrosion properties at high temperatures, such characteristics are very attractive for applications in the aeronautical, aerospace and automotive industries. However, the current high selling price, due to high costs of production and raw materials and the need of very specific equipment, are limitative factors for further applications. With the end of the cold war, and the decrease of traditional markets of TiAl, the strategy to develop other applications, strongly depends on the decrease of production costs. An alternative to the present production routes might be the use of traditional casting techniques, by induction melting of the alloy in a ceramic crucible and pouring into ceramic moulds, made by the investment casting process. However, due to the high reactivity of Ti alloys, the use of traditional ceramic materials cannot be used, as they lead to oxide formation and oxygen pick up both from the crucible and the moulding materials. In this work, the relative oxygen concentration of Ti-48Al castings was measured by SIMS — Secondary Ion Mass Spectrometry. This technique provides a direct measurement of the isotopic composition with high sensitivity. The cylindrical samples were specially prepared to allow the analysis of the area close to the border. Oxygen profiles were acquired for samples obtained by with different mould materials. The comparison of such profiles with hardness profiles, give insight in the significance of the oxygen concentration in the properties of the alloy and in the choice of the most suitable materials for TiAl production(undefined

Dimensionamento de plataformas offshore de concreto utilizando a teoria de cascas de três camadas

Peer Reviewe

Morphological alterations and gene and protein expression profiling of bladder tumor cells after treatment with gemcitabine.

Chemical agents used in cancer therapy are associated with cell cycle arrest, activation or deactivation of mechanisms\ud associated to DNA repair and apoptosis. However, due to the complexity of biological systems, the molecular\ud mechanisms responsible for these activities are not fully understood. Thus, studies about gene and protein expression\ud have shown promising results for understanding the mechanisms related to cellular responses and regression of cancer\ud after chemotherapy. This study aimed to evaluate the gene and protein expression profiling in bladder transitional cell\ud carcinoma (TCC) with different TP53 status after gemcitabine (1.56 μM) treatment. The RT4 (grade 1, TP53 wild\ud type), 5637 (grade 2, TP53 mutated) and T24 (grade 3, TP53 mutated) cell lines were used. PCR arrays and mass\ud spectrometry were used to analyze gene and protein expression, respectively. Morphological alterations were observed\ud using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of PCR array\ud showed that gemcitabine activity was mainly related to CDKN1A, GADD45A and SERTDA1 overexpression, and BAX\ud overexpression only in the wild type TP53 cells. Mass spectrometry demonstrated that gemcitabine modulated the protein\ud expression, especially those from genes related to apoptosis, transport of vesicles and stress response. Analyses using SEM\ud and TEM showed changes in cell morphology independently on the cell line studied. The observed decreased number of\ud microvillus suggests low contact among the cells and between cell and extracellular matrix; irregular forms might indicate\ud actin cytoskeleton deregulation; and the reduction in the amount of organelles and core size might indicate reduced\ud cellular metabolism. In conclusion, independently on TP53 status or grade of bladder tumor, gemcitabine modulated\ud genes related to the cell cycle and apoptosis, that reflected in morphological changes indicative of future cell death.FAPESPCNP

Flavonoid Apigenin Is an Inhibitor of the NAD+ase CD38: Implications for Cellular NAD+ Metabolism, Protein Acetylation, and Treatment of Metabolic Syndrome

Metabolic syndrome is a growing health problem worldwide. It is therefore imperative to develop new strategies to treat this pathology. In the past years, the manipulation of NAD+ metabolism has emerged as a plausible strategy to ameliorate metabolic syndrome. In particular, an increase in cellular NAD+ levels has beneficial effects, likely because of the activation of sirtuins. Previously, we reported that CD38 is the primary NAD+ase in mammals. Moreover, CD38 knockout mice have higher NAD+ levels and are protected against obesity and metabolic syndrome. Here, we show that CD38 regulates global protein acetylation through changes in NAD+ levels and sirtuin activity. In addition, we characterize two CD38 inhibitors: quercetin and apigenin. We show that pharmacological inhibition of CD38 results in higher intracellular NAD+ levels and that treatment of cell cultures with apigenin decreases global acetylation as well as the acetylation of p53 and RelA-p65. Finally, apigenin administration to obese mice increases NAD+ levels, decreases global protein acetylation, and improves several aspects of glucose and lipid homeostasis. Our results show that CD38 is a novel pharmacological target to treat metabolic diseases via NAD+-dependent pathways

Exploring the Pharmacological Potential of Promiscuous Host-Defense Peptides: From Natural Screenings to Biotechnological Applications

In the last few years, the number of bacteria with enhanced resistance to conventional antibiotics has dramatically increased. Most of such bacteria belong to regular microbial flora, becoming a real challenge, especially for immune-depressed patients. Since the treatment is sometimes extremely expensive, and in some circumstances completely inefficient for the most severe cases, researchers are still determined to discover novel compounds. Among them, host-defense peptides (HDPs) have been found as the first natural barrier against microorganisms in nearly all living groups. This molecular class has been gaining attention every day for multiple reasons. For decades, it was believed that these defense peptides had been involved only with the permeation of the lipid bilayer in pathogen membranes, their main target. Currently, it is known that these peptides can bind to numerous targets, as well as lipids including proteins and carbohydrates, from the surface to deep within the cell. Moreover, by using in vivo models, it was shown that HDPs could act both in pathogens and cognate hosts, improving immunological functions as well as acting through multiple pathways to control infections. This review focuses on structural and functional properties of HDP peptides and the additional strategies used to select them. Furthermore, strategies to avoid problems in large-scale manufacture by using molecular and biochemical techniques will also be explored. In summary, this review intends to construct a bridge between academic research and pharmaceutical industry, providing novel insights into the utilization of HDPs against resistant bacterial strains that cause infections in humans

Understanding the interactions of imidazolium-based ionic liquids with cell membrane models

Cell membrane models have been used to evaluate the interactions of various imidazolium-based ionic liquids (ILs) with Langmuir monolayers of two types of phospholipids and cholesterol. Data from surface pressure isotherms, Brewster angle microscopy (BAM) and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) pointed to significant effects on the monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol, used to mimic the membranes of eukaryotic cells, for ILs containing more than 6 carbon atoms in the alkyl chain (i.e. n > 6). For ILs with less hydrophobic tails (n ≤ 6) and low concentrations, the effects were almost negligible, therefore, such ILs should not be toxic to eukaryotic cells. The hydrophobicity of the anion was also proved to be relevant, with larger impact from ILs containing tetrafluoroborate ([BF4]-) than chloride (Cl-). Molecular dynamics simulations for DPPC monolayers at the surface of aqueous solutions of alkylimidazolium chloride ([Cnmim]Cl) confirm the penetration of the IL cations with longer alkyl chains into the phospholid monolayer and provide information on their location and orientation within the monolayer. For monolayers of dipalmitoylphosphatidyl glycerol (DPPG), which is negatively charged like bacteria cell membranes, the ILs induced much larger effects. Similarly to the results for DPPC and cholesterol, effects increased with the number of carbon atoms in the alkyl chain and with a more hydrophobic anion [BF4]-. Overall, the approach used can provide relevant information of molecular-level interactions behind the toxicity mechanisms and support the design of (quantitative) structure-activity relationship models, which may help design more efficient and environmentally friendly ILs.publishe