Elektrokemijsko ispitivanje stabilnosti pasivnog stanja i korozijske otpornosti supermartenzitnog nehrđajućeg čelika

On low interstitial - supermartensitic stainless steels (X1CrNiMo 12-5-1, X2CrNiMo 13-6-2, X1CrNiMo 12-6-2) the electrochemical potentiodynamic polarization tests were carried out and the passive state stability and localized corrosion resistance were compared and evaluated. The effect of quenching and tempering as well as the changes in microstructure on polarisation curves and corrosion properties at room temperature were established. Small differences in chemical composition of steels were also registered on their corrosion parameters changes and resistance.Rad prikazuje usporedbu i procjenu stabilnosti pasivnog stanja i lokalnu otpornost koroziji temeljem ispitivanja elektrokemijske potenciodinamičke polarizacije nisko-intersticijskih supermartenzitnih nehrđajućih čelika (X1CrNiMo 12-5-1, X2CrNiMo 13-6-2, X1CrNiMo 12-6-2). Utvrđeni su utjecaj poboljšavanja čelika i mikrostrukturne promjene na polarizacijskim krivuljama uzoraka te korozijska svojstva pri sobnoj temperaturi. Uočena je i povezanost malih odstupanja kemijskog sastava čelika s promjenom korozijskih parametera i korozijskom otpornošću

Trends in the Electrochemical Polarization Potentiodynamic Reactivation Method – EPR

This method designed to examine the susceptibility to nonuniform corrosion, ranks among the more successful technique developments. One of its numerous advantages is that it allows nondestructive, on-site examination. EPR measurements are used to establish the resistance of stainless steels and alloys to intergranular corrosion and stress corrosion cracking e.g. in nuclear engineering applications as well as to study grain boundary precipitation and other minute local changes in alloy composition and structure. By the EPR test, the specimen and/or the field object (working electrode) is tested in acid solutions, most often in solutions of sulfuric acid (c = 0.01–5 mol dm–3 H2SO4) and potassium thiocyanate (c = 0.001 to 0.1 mol dm–3 KSCN). The principle of the measurements is to reactivate the sample from the incomplete passivity region. This indicates local changes in chemical composition in relation to phase transformations

Involvement of Purinergic P2X4 Receptors in Alcohol Intake of High-Alcohol-Drinking (HAD) Rats

Background: The P2X4 receptor is thought to be involved in regulating alcohol-consuming behaviors and ethanol (EtOH) has been reported to inhibit P2X4 receptors. Ivermectin is an anti-parasitic agent that acts as a positive allosteric modulator of the P2X4 receptor. The current study examined the effects of systemically- and centrally-administered ivermectin on alcohol drinking of replicate lines of high-alcohol-drinking (HAD-1/HAD-2) rats, and the effects of lentiviral-delivered short-hairpin RNAs (shRNAs) targeting P2rx4 on EtOH intake of female HAD2 rats. Method: For the 1st experiment, adult male HAD-1 & HAD-2 rats were given 24-hr free-choice access to 15% EtOH vs. water. Dose-response effects of ivermectin (1.5 to 7.5 mg/kg i.p.) on EtOH intake were determined; the effects of ivermectin were then examined for 2% w/v sucrose intake over 5 consecutive days. In the 2nd experiment, female HAD-2 rats were trained to consume 15% EtOH under 2-hr limited access conditions, and dose-response effects of intracerebroventricular (ICV) administration of ivermectin (0.5 to 2.0 μg) were determined over 5 consecutive days. The 3rd experiment determined the effects of microinfusion of a lentivirus expressing P2rx4 shRNAs into the posterior ventral tegmental area (VTA) on 24-hr EtOH free-choice drinking of female HAD-2 rats. Results: The highest i.p. dose of ivermectin reduced alcohol drinking (30-45%) in both rat lines, but did not alter sucrose intake. HAD-2 rats appeared to be more sensitive than HAD1 rats to the effects of ivermectin. ICV administration of ivermectin reduced 2-hr limited access intake (∼35%) of femal

Van der Waals epitaxy growth of 2D ferromagnetic Cr_(1+δ)Te₂ nanolayers with concentration-tunable magnetic anisotropy

Cr(1+δ)Te2 are pseudo-layered compounds consisting of CrTe2 transition metal dichalcogenide (TMD) layers with additional (δ) self-intercalated Cr atoms. The recent search for ferromagnetic 2D materials revived the interest into chromium tellurides. Here, Cr(1+δ)Te2 nanolayers are epitaxially grown on MoS2 (0001), forming prototypical van der Waals heterostructures. Under optimized growth conditions, ultrathin films of only two TMD layers with a single intercalated Cr-layer are achieved, forming a 2D sheet with van der Waals surfaces. Detailed compositional and structural characterization by scanning tunneling microscopy, grazing incidence x-ray diffraction, and high-resolution Rutherford backscattering indicate the layer-by-layer growth and that the δ can be tuned by post-growth annealing in a range between ∼0.5 and 1. X-ray magnetic circular dichroism and magnetometry measurements demonstrate that all self-intercalated Cr(1+δ)Te2 nanolayers exhibit strong ferromagnetism with magnetic moments larger than 3μB per Cr-atom. The magnetic properties are maintained in the ultrathin limit of a material with a single intercalation layer. Interestingly, the magnetic anisotropy can be tuned from close to isotropic (δ = 1) to a desirable perpendicular anisotropy for low δ values. Thus, the bottom-up growth of these 2D Cr(1+δ)Te2 sheets is a promising approach for designing magnetic van der Waals heterostructures

Reduced Levels of mGlu2 Receptors within the Prelimbic Cortex Are Not Associated with Elevated Glutamate Transmission or High Alcohol Drinking

Background A Grm2 cys407* stop codon mutation, which results in a loss of the metabotropic glutamate 2 (mGlu2) receptor protein, was identified as being associated with high alcohol drinking by alcohol-preferring (P) rats. The objectives of the current study were to characterize the effects of reduced levels of mGlu2 receptors on glutamate transmission and alcohol drinking. Methods Quantitative no-net-flux microdialysis was used to test the hypothesis that basal extracellular glutamate levels in the prelimbic (PL) cortex and nucleus accumbens shell (NACsh) will be higher in P than Wistar rats. A lentiviral-delivered short-hairpin RNA (shRNA)-mediated knockdown was used to test the hypothesis that reduced levels of mGlu2 receptors within the PL cortex will increase voluntary alcohol drinking by Wistar rats. A linear regression analysis was used to test the hypothesis that there will be a significant correlation between the Grm2 cys407* mutation and level of alcohol intake. Results Extracellular glutamate concentrations within the PL cortex (3.6 ± 0.6 vs. 6.4 ± 0.6 μM) and NACsh (3.2 ± 0.4 vs. 6.6 ± 0.6 μM) were significantly lower in female P than female Wistar rats. Western blot detected the presence of mGlu2 receptors in these regions of female Wistar rats, but not female P rats. Micro-infusion of shRNAs into the PL cortex significantly reduced local mGlu2 receptor levels (by 40%), but did not alter voluntary alcohol drinking in male Wistar rats. In addition, there was no significant correlation between the Grm2 mutation and alcohol intake in 36 rodent lines (r = 0.29, p > 0.05). Conclusions Collectively, these results suggest a lack of association between the loss of mGlu2 receptors and glutamate transmission in the NACsh and PL cortex of female P rats, and between the level of mGlu2 receptors in the PL cortex and alcohol drinking of male Wistar rats

A guide to laboratory use of the squid Loligo pealei

From the Preface: Unfortunately, a guide like this one does not happen simply. It is the product of polite requests (at first polite, anyway) from colleagues, of mutual nagging, and of wives with persistant memories. What we are attempting to achieve with this contribution is a consolidation of many years of personal experience with squid into a source of practical information hopefully useful to the increasing number of people working with the squid. One does not undertake the task of preparing such a guide for a limited audience with unreserved enthusiasm. It always seems the same amount of work could produce something for a larger audience and therefore, hopefully, of greater significance. On the other hand when the hours and days spent on developing handling procedures, techniques, and "tricks of the squid trade" are considered it seems untenable not to pass this otherwise unpublishable data on in hope of saving others like pain and time. Therefore, what we have attempted to do is informally put together information that should prove useful to people interested in all aspects of squid biology. In this way we hope to make the laboratory utilization of the squid more efficient not only from the standpoint of the investigator and the collector but also for the future of the species Loligo pealei

Thermo-magnetic-fluid dynamics analysis of an OsNAN distribution transformer cooled with mineral oil and biodegradable esters

This work introduces a coupled electromagnetic, thermal and fluid flow analysis of an oil-natural air-natural distribution transformer in order to study the changes in the heat dissipation performance when a biodegradable ester is used to cool the device instead of mineral oil. The transformer has a rated power of 315kVA and a voltage ratio of 13.2kV / 0.4kV. The heat losses in the magnetic core and the windings are computed with the ANSYS® Maxwell software and they are transferred as volume heat source terms to compute the heat conduction. The natural convection of the fluid flow is taken into account using a temperature-dependent density. The heat conduction through the solid walls and radiators panels are also considered. The thermo–hydraulic problem is solved with the software Code_Saturne. Data from experimental tests carried out with mineral oil are used to validate the numerical simulations. Equivalent and anisotropic thermal conductivities in the core and the windings are calculated both with a semi-analytic procedure and finite element simulations to simplify the heat conduction model in the active parts. It is found that, after reaching a steady state, the transformer cooled with the ester shows a temperature difference between specific locations at the top and the bottom higher than that cooled with mineral oil. The magnetic core and the windings also work hotter when ester is used. Finally, the analysis of the flow through the cooling ducts of the windings confirms that the oil velocity is, on average, 25% higher than the ester one.Fil: Garelli, Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Rios Rodriguez, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Kubiczek, K.. Silesian University Of Technology; PoloniaFil: Lasek, P.. Silesian University Of Technology; PoloniaFil: Stepien, M.. Silesian University Of Technology; PoloniaFil: Smolka, J.. Silesian University Of Technology; PoloniaFil: Storti, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Pessolani, F.. No especifíca;Fil: Amadei, M.. No especifíca

Lmo4 in the Basolateral Complex of the Amygdala Modulates Fear Learning

Pavlovian fear conditioning is an associative learning paradigm in which mice learn to associate a neutral conditioned stimulus with an aversive unconditioned stimulus. In this study, we demonstrate a novel role for the transcriptional regulator Lmo4 in fear learning. LMO4 is predominantly expressed in pyramidal projection neurons of the basolateral complex of the amygdala (BLC). Mice heterozygous for a genetrap insertion in the Lmo4 locus (Lmo4gt/+), which express 50% less Lmo4 than their wild type (WT) counterparts display enhanced freezing to both the context and the cue in which they received the aversive stimulus. Small-hairpin RNA-mediated knockdown of Lmo4 in the BLC, but not the dentate gyrus region of the hippocampus recapitulated this enhanced conditioning phenotype, suggesting an adult- and brain region-specific role for Lmo4 in fear learning. Immunohistochemical analyses revealed an increase in the number of c-Fos positive puncta in the BLC of Lmo4gt/+ mice in comparison to their WT counterparts after fear conditioning. Lastly, we measured anxiety-like behavior in Lmo4gt/+ mice and in mice with BLC-specific downregulation of Lmo4 using the elevated plus maze, open field, and light/dark box tests. Global or BLC-specific knockdown of Lmo4 did not significantly affect anxiety-like behavior. These results suggest a selective role for LMO4 in the BLC in modulating learned but not unlearned fear

Reduction of alcohol drinking of alcohol-preferring (P) and high-alcohol drinking (HAD1) rats by targeting phosphodiesterase-4 (PDE4)

RATIONALE: Phosphodiesterase-4 (PDE4) and neuroimmune signaling have been posited to regulate alcohol drinking. OBJECTIVES: This study evaluated the involvement of PDE4 and Il22ra2 on ethanol (EtOH) intake by alcohol-preferring (P) and high-alcohol-drinking (HAD1) rats. METHODS: Exp 1 determined the dose-response effects of PDE4 inhibitors, rolipram, and Ro 20-1724, on 2 h/day free-choice EtOH intake by adult P and HAD1 rats. Exps 2-3 examined the effects of repeated administration with the PDE4 inhibitors on EtOH or sucrose intake and locomotor behavior. Exp 4 determined Pde4-associated gene expression differences in subregions of the extended amygdala, between high- and low-alcohol-consuming rat lines. Exp 5 evaluated the effects of infusing short hairpin RNA to knock down Il22ra2 in the nucleus accumbens (NAc) shell on a 24-h free-choice EtOH drinking by P rats. RESULTS: Administration of rolipram or Ro 20-1724 reduced EtOH intake by P rats; Ro 20-1724 reduced EtOH intake by HAD1 rats. Repeated rolipram or Ro 20-1724 exposure reduced EtOH intake by P and HAD1 rats. PDE4 inhibition induced motor impairment during the first hour of EtOH intake by P rats. Higher gene expression levels for PDE4A were found in the NAc shell of P vs NP rats. ShRNAs targeting Il22ra2 in the NAc shell significantly reduced chronic EtOH intake. CONCLUSIONS: PDE4 and neuroinflammatory/immune signaling pathways could represent molecular targets for the treatment of alcohol use disorders in genetically predisposed subjects. This study underscores the importance of testing compounds over multiple days and rat lines when determining efficacy to disrupt excessive alcohol intake