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Austenitic stainless steels (ASS) are among the most used structural materials because of their excellent mechanical and corrosive properties. In addition, 316L ASS has excellent weldability because of its low carbon content. This steel normally contains 5–10% residual delta ferrite to avoid hot cracking and micro-fissuring of the weld metal. Many studies show that selective dissolution of austenite or ferrite can occur in 316L steel. In a survey of the selective dissolution of phases in duplex stainless steel (DSS), Lo and coauthors studied the effect of electrolyte composition (H2SO4 + HCl solutions) on the active–passive transition. They showed that corrosion occurred only in the austenitic phase in solutions of 2M H2SO4 + 0.25–1.2M of HCl. Increasing the % of HCl, > 1.2%, austenite, and ferrite contributed to the corrosion process. The present authors did not find the effect of this electrolyte in the study of selective corrosion in 316L ASS welded in the literature. Therefore, this study aims to determine how the phases behave on 316L ASS by applying 2M H2SO4 + 1.5M HCl solution. In this work, we welded the steel by the autogenous TIG process using three heat inputs. The purpose of welding was to obtain different amounts and morphology of ferrite and determine whether this affected the selective dissolution of the phases. After the corrosion tests, the samples showed selective austenite corrosion irrespective of the volume fraction and morphology of the ferrite. In summary, the corrosive etches severely consumed the austenite because of the significant difference in the electrochemical potential between the phases. Therefore, with more nickel, austenite functioned as an anodic region, and the δ-ferrite, with more chromium, worked as a cathodic region.

Alzheimer's disease (AD) is the most common form of dementia in the elderly individuals, resulting from a complex interaction between environmental and genetic factors. Impaired brain iron homeostasis has been recognized as an important mechanism underlying the pathogenesis of this disease. Nevertheless, the knowledge gathered so far at the systemic level is clearly insufficient. Herein, we used an integrative approach to study iron metabolism in the periphery, at both genotypic and phenotypic levels, in a sample of 116 patients with AD and 89 healthy control subjects. To assess the potential impact of iron metabolism on the risk of developing AD, genetic analyses were performed along with the evaluation of the iron status profile in peripheral blood by biochemical and gene expression studies. The results obtained showed a significant decrease of serum iron, ferritin, and transferrin concentrations in patients compared with the control subjects. Also, a significant decrease of ferroportin (SLC40A1) and both transferrin receptors TFRC and TFR2 transcripts was found in peripheral blood mononuclear cells from patients. At the genetic level, significant associations with AD were found for single nucleotide polymorphisms in TF, TFR2, ACO1, and SLC40A1 genes. Apolipoprotein E gene, a well-known risk factor for AD, was also found significantly associated with the disease in this study. Taken together, we hypothesize that the alterations on systemic iron status observed in patients could reflect an iron homeostasis dysregulation, particularly in cellular iron efflux. The intracellular iron accumulation would lead to a rise in oxidative damage, contributing to AD pathophysiology.

This research was supported by the Fundação para a Ciência e a Tecnologia (FCT) [SFRH/BPD/29354/2006 to MM, SFRH/BD/60718/2009 to BS, and SFRH/BD/48671/2008 to LM]; Fundação Astrazeneca (Research Grant awarded through the “Programme of Support to Research”); Instituto Nacional de Saúde Dr. Ricardo Jorge; Portuguese Ministry of Health (Research Grant 53/2007 of the “Comissão de Fomento da Investigação em Cuidados de Saúde”); Lundbeck Portugal, Lda (Research Grant). Introduction: Alzheimer’s disease (AD) is the most common neurodegenerative disorder and the leading cause of dementia worldwide. Because of the clinical interest in its early diagnosis and prediction of patient evolution and prognosis, the identification of AD biomarkers is of crucial importance. Several lines of evidence implicate an imbalance of the redox-active biometals in AD. Metal-catalyzed hydroxyl radicals are potent mediators of cellular injury and are central to the oxidative injury hypothesis of AD pathogenesis [1,2]. Importantly, previous genetic and biochemical studies in AD patients support a concerted systemic iron metabolism dysregulation, namely at the level of cellular iron efflux [3]. Herein, we intended to further understand the molecular mechanisms underlying iron homeostasis in this pathology. In order to achieve this goal, the expression of specific iron metabolism-related genes directly involved in iron metabolism regulation and cellular iron export was measured in peripheral blood mononuclear cells from AD patients and healthy controls. Also, serum ceruloplasmin (CP) concentration and its oxidase activity were measured in all participants in the study, given the known role of this oxidase in facilitating iron exit from cells. Through this study we expect to further clarify the contribution of iron metabolism disruption to the etiopathogenesis of AD.

Copyright ©2012 IOS Press All rights reserved., We review the electrophysiological studies concerning the effects of caffeine on muscle, lower and upper motor neuron excitability and cognition. Several different methods have been used, such as electromyography, recruitment analysis, H-reflex, transcranial magnetic stimulation (TMS), electroencephalography and event-related potentials. The positive effect of caffeine on vigilance, attention, speed of reaction, information processing and arousal is supported by a number of electrophysiological studies. The evidence in favor of an increased muscle fiber resistance is not definitive, but higher or lower motor neuron excitability can occur as a consequence of a greater excitation of the descending input from the brainstem and upper motor neurons. TMS can address the influence of caffeine on the upper motor neuron. Previous studies showed that cortico-motor threshold and intracortical excitatory and inhibitory pathways are not influenced by caffeine. Nonetheless, our results indicate that cortical silent period (CSP) is reduced in resting muscles after caffeine consumption, when stimulating the motor cortex with intensities slightly above threshold. We present new data demonstrating that this effect is also observed in fatigued muscle. We conclude that CSP can be considered a surrogate marker of the effect of caffeine in the brain, in particular of its central ergogenic effect.

Alzheimer's disease (AD) is a neurodegenerative disorder of still unknown etiology and the leading cause of dementia worldwide. Besides its main neuropathological hallmarks, a dysfunctional homeostasis of transition metals has been reported to play a pivotal role in the pathogenesis of this disease. Dysregulation of iron (Fe) metabolism in AD has been suggested, particularly at the level of cellular iron efflux. Herein, we intended to further clarify the molecular mechanisms underlying Fe homeostasis in AD. In order to achieve this goal, the expression of specific Fe metabolism-related genes directly involved in Fe regulation and export was assessed in peripheral blood mononuclear cells (PBMCs) from 73AD patients and 74 controls by quantitative PCR. The results obtained showed a significant decrease in the expression of aconitase 1 (ACO1; P=0.007); ceruloplasmin (CP; P