Estimation of the Effective Thermal Properties in a Metallic Medium by an Inverse Technique using Temperatures Measureme

In order to master the use of electric machines and to minimize its thermal losses, the knowledge of thermo-physical properties of metallic materials that constitute them, is important. This study deals with the estimation of several thermal properties in a metallic medium. The system under investigation is a rectangular metallic plate, which is submitted to an homogenous heat power on the volume sample. The direct problem simulates numerically the system and the experimental conditions. An iterative procedure, based on minimizing a sum of squares norm with the Levenberg-Marquardt method, is used to solve the inverse problem. In order to characterize the thermal behavior of metallic materials, an experimental set-up was built. The measured temperature data using infrared camera are used to estimate the effective thermal conductivity, the effective volumetric heat capacity as well as the global heat transfer coefficient with the environment

Nanostructured Mo 3 Al-based composites strengthened by Al 2 O 3 precipitates

a b s t r a c t Nanostructured Mo 3 Al-based composites strengthened by Al 2 O 3 precipitates were obtained from a Mo 75 Al 25 (at.%) + 15 vol.% Al 2 O 3 mixture that was synthesized by mechanical alloying (MA) from Mo, Al and Al 2 O 3 powders and subsequently annealed. The influence of rotation speed and milling time on the structure and mechanical properties of the final compacts, before and after annealing, was studied. After milling at 150 and 300 rpm, mainly a metastable BCC-Mo(Al) solid solution was observed. With subsequent annealing at 900 • C this solid solution decomposed into Mo + Mo 3 Al (an intermetallic phase). The mechanical properties of the samples mechanically alloyed at 300 rpm are in general better than the ones of samples alloyed at 150 rpm. Values of H = 18.4 GPa, y = 6.2 MPa and E = 227 GPa were obtained from the 300 rpm samples, after annealing at 900 • C. The work-hardening coefficient value, n, obtained from the annealed sample milled at 150 rpm is higher than the one from the as-milled sample (0.05 in contrast to 0.02, respectively), indicating a slight increase in ductility. For 300 rpm no significant variation of n was apparent after annealing (n was about 0.02)

Pituitary Adenylate Cyclase Activating Peptide (1-38) and its analog (Acetyl-[Ala15, Ala20] PACAP 38-polyamide) reverse methacholine airway hyperresponsiveness in rats

O objetivo deste estudo foi investigar funcionalmente e estruturalmente efeito broncodilatador do peptídeo ativador da adenilato ciclase pituitária (PACAP1-38) e da acetil-[Ala15, Ala20]PACAP 38-poliamida, potente análogo do PACAP-38, nos ratos desafiados pelo metacolina (MeCh). Ratos Wistar machos foram aleatoriamente divididos em cinco grupos. Grupos 1 e 2, inalando aerossóis de solução salina ou doses crescentes de MeCh (0,5, 1, 2,12, 4,25, 8,5, 17, 34 e 68 mg/L). Os outros grupos recebendo terbutalina (Terb) (250 µg/rato) (10-6M), PACAP-38 (50 µg/rato) (0.1 mM) ou análogo do PACAP-38 (50 µg/rato) associados a MeCh na dose de 4,25 mg/L. A resistência pulmonar total (RL) foi registrada antes e 2 min após a administração de Mech pelo equipamento pneumomultiteste. A administração MeCh induziu aumento significativo e dose dependente (pThe aim of this study was to investigate both functionally and structurally bronchodilator effects of Pituitary adenylate cyclase activating peptide (PACAP38) and acetyl-[Ala15, Ala20] PACAP38-polyamide, a potent PACAP38 analog, in rats challenged by methacholine (MeCh). Male Wistar rats were divided randomly into five groups. Groups 1 and 2 inhaled respectively aerosols of saline or increasing doses of MeCh (0.5, 1, 2.12, 4.25, 8.5, 17, 34 and 68mg/L). The other groups received terbutaline (Terb) (250 µg/rat) (10-6 M), PACAP38 (50 µg/rat) (0.1 mM) or PACAP38 analog (50 µg/rat) associated to MeCh from the dose of 4.25 mg/L. Total lung resistances (RL) were recorded before and 2 min after MeCh administration by pneumomultitest equipment. MeCh administration induced a significant and a dose-dependent increase (

Astrocyte-Derived Tissue Transglutaminase Interacts with Fibronectin: A Role in Astrocyte Adhesion and Migration?

An important neuropathological feature of neuroinflammatory processes that occur during e.g. Multiple Sclerosis (MS) is the formation of an astroglial scar. Astroglial scar formation is facilitated by the interaction between astrocytes and extracellular matrix proteins (ECM) such as fibronectin. Since there is evidence indicating that glial scars strongly inhibit both axon growth and (re)myelination in brain lesions, it is important to understand the factors that contribute to the interaction between astrocytes and ECM proteins. Tissue Transglutaminase (TG2) is a multifunctional enzyme with an ubiquitous tissue distribution, being clearly present within the brain. It has been shown that inflammatory cytokines can enhance TG2 activity. In addition, TG2 can mediate cell adhesion and migration and it binds fibronectin with high affinity. We therefore hypothesized that TG2 is involved in astrocyte-fibronectin interactions. Our studies using primary rat astrocytes show that intracellular and cell surface expression and activity of TG2 is increased after treatment with pro-inflammatory cytokines. Astrocyte-derived TG2 interacts with fibronectin and is involved in astrocyte adhesion onto and migration across fibronectin. TG2 is involved in stimulating focal adhesion formation which is necessary for the interaction of astrocytes with ECM proteins. We conclude that astrocyte-derived TG2 contributes to the interaction between astrocytes and fibronectin. It might thereby regulate ECM remodeling and possibly glial scarring