Stress corrosion cracking in Al-Zn-Mg-Cu aluminum alloys in saline environments

Copyright 2013 ASM International. This paper was published in Metallurgical and Materials Transactions A, 44A(3), 1230 - 1253, and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.Stress corrosion cracking of Al-Zn-Mg-Cu (AA7xxx) aluminum alloys exposed to saline environments at temperatures ranging from 293 K to 353 K (20 °C to 80 °C) has been reviewed with particular attention to the influences of alloy composition and temper, and bulk and local environmental conditions. Stress corrosion crack (SCC) growth rates at room temperature for peak- and over-aged tempers in saline environments are minimized for Al-Zn-Mg-Cu alloys containing less than ~8 wt pct Zn when Zn/Mg ratios are ranging from 2 to 3, excess magnesium levels are less than 1 wt pct, and copper content is either less than ~0.2 wt pct or ranging from 1.3 to 2 wt pct. A minimum chloride ion concentration of ~0.01 M is required for crack growth rates to exceed those in distilled water, which insures that the local solution pH in crack-tip regions can be maintained at less than 4. Crack growth rates in saline solution without other additions gradually increase with bulk chloride ion concentrations up to around 0.6 M NaCl, whereas in solutions with sufficiently low dichromate (or chromate), inhibitor additions are insensitive to the bulk chloride concentration and are typically at least double those observed without the additions. DCB specimens, fatigue pre-cracked in air before immersion in a saline environment, show an initial period with no detectible crack growth, followed by crack growth at the distilled water rate, and then transition to a higher crack growth rate typical of region 2 crack growth in the saline environment. Time spent in each stage depends on the type of pre-crack (“pop-in” vs fatigue), applied stress intensity factor, alloy chemistry, bulk environment, and, if applied, the external polarization. Apparent activation energies (E a) for SCC growth in Al-Zn-Mg-Cu alloys exposed to 0.6 M NaCl over the temperatures ranging from 293 K to 353 K (20 °C to 80 °C) for under-, peak-, and over-aged low-copper-containing alloys (~0.8 wt pct), they are typically ranging from 20 to 40 kJ/mol for under- and peak-aged alloys, and based on limited data, around 85 kJ/mol for over-aged tempers. This means that crack propagation in saline environments is most likely to occur by a hydrogen-related process for low-copper-containing Al-Zn-Mg-Cu alloys in under-, peak- and over-aged tempers, and for high-copper alloys in under- and peak-aged tempers. For over-aged high-copper-containing alloys, cracking is most probably under anodic dissolution control. Future stress corrosion studies should focus on understanding the factors that control crack initiation, and insuring that the next generation of higher performance Al-Zn-Mg-Cu alloys has similar longer crack initiation times and crack propagation rates to those of the incumbent alloys in an over-aged condition where crack rates are less than 1 mm/month at a high stress intensity factor

Szívinfarktus miatt kezelt betegek korai és késői prognózisa. Magyar Infarctus Regiszter Vizsgálat

Introduction: Mortality data of patients with acute myocardial infarction are incomplete in Hungary. Aim: The aim of the authors was to analyse the data of 8582 myocardial infarction patients (4981 with ST-elevation myocardial infarction) registered in the Hungarian Myocardial Infarction Register in order to define the hospital, 30-day, and 1-year mortality. To evaluate the prehospital mortality of myocardial infarction, all myocardial infarction and sudden death were registered in five districts of Budapest. Method: Multivariate logistic regression was performed to define risk factors of mortality and the model were assessed using c statistics. Results: The hospital, 30-day and 1-year mortality of patients with ST elevation myocardial infarction were 3.7%, 9.5% and 16.5%, respectively. In patients without ST elevation myocardial infarction these figures were 4%, 9.8% and 21.7%, respectively. The 1-year mortality of patients without ST elevation was higher than those of with ST elevation and the difference was statistically significant. Age, Killip class, diabetes mellitus, history of stroke and myocardial infarction were independent predictors of death. Coronary intervention improved the prognosis of patients with myocardial infarction significantly. Conclusions: The rate of pre-hospital mortality was considerably high; 72.5% of 30 day mortality occurred before admission to hospital. Orv. Hetil., 2013, 154, 1297-1302

Baseline characteristics of patients in the reduction of events with darbepoetin alfa in heart failure trial (RED-HF)

<p>Aims: This report describes the baseline characteristics of patients in the Reduction of Events with Darbepoetin alfa in Heart Failure trial (RED-HF) which is testing the hypothesis that anaemia correction with darbepoetin alfa will reduce the composite endpoint of death from any cause or hospital admission for worsening heart failure, and improve other outcomes.</p> <p>Methods and results: Key demographic, clinical, and laboratory findings, along with baseline treatment, are reported and compared with those of patients in other recent clinical trials in heart failure. Compared with other recent trials, RED-HF enrolled more elderly [mean age 70 (SD 11.4) years], female (41%), and black (9%) patients. RED-HF patients more often had diabetes (46%) and renal impairment (72% had an estimated glomerular filtration rate <60 mL/min/1.73 m2). Patients in RED-HF had heart failure of longer duration [5.3 (5.4) years], worse NYHA class (35% II, 63% III, and 2% IV), and more signs of congestion. Mean EF was 30% (6.8%). RED-HF patients were well treated at randomization, and pharmacological therapy at baseline was broadly similar to that of other recent trials, taking account of study-specific inclusion/exclusion criteria. Median (interquartile range) haemoglobin at baseline was 112 (106–117) g/L.</p> <p>Conclusion: The anaemic patients enrolled in RED-HF were older, moderately to markedly symptomatic, and had extensive co-morbidity.</p&gt

Effect of aliskiren on post-discharge outcomes among diabetic and non-diabetic patients hospitalized for heart failure: insights from the ASTRONAUT trial

Aims The objective of the Aliskiren Trial on Acute Heart Failure Outcomes (ASTRONAUT) was to determine whether aliskiren, a direct renin inhibitor, would improve post-discharge outcomes in patients with hospitalization for heart failure (HHF) with reduced ejection fraction. Pre-specified subgroup analyses suggested potential heterogeneity in post-discharge outcomes with aliskiren in patients with and without baseline diabetes mellitus (DM). Methods and results ASTRONAUT included 953 patients without DM (aliskiren 489; placebo 464) and 662 patients with DM (aliskiren 319; placebo 343) (as reported by study investigators). Study endpoints included the first occurrence of cardiovascular death or HHF within 6 and 12 months, all-cause death within 6 and 12 months, and change from baseline in N-terminal pro-B-type natriuretic peptide (NT-proBNP) at 1, 6, and 12 months. Data regarding risk of hyperkalaemia, renal impairment, and hypotension, and changes in additional serum biomarkers were collected. The effect of aliskiren on cardiovascular death or HHF within 6 months (primary endpoint) did not significantly differ by baseline DM status (P = 0.08 for interaction), but reached statistical significance at 12 months (non-DM: HR: 0.80, 95% CI: 0.64-0.99; DM: HR: 1.16, 95% CI: 0.91-1.47; P = 0.03 for interaction). Risk of 12-month all-cause death with aliskiren significantly differed by the presence of baseline DM (non-DM: HR: 0.69, 95% CI: 0.50-0.94; DM: HR: 1.64, 95% CI: 1.15-2.33; P < 0.01 for interaction). Among non-diabetics, aliskiren significantly reduced NT-proBNP through 6 months and plasma troponin I and aldosterone through 12 months, as compared to placebo. Among diabetic patients, aliskiren reduced plasma troponin I and aldosterone relative to placebo through 1 month only. There was a trend towards differing risk of post-baseline potassium ≥6 mmol/L with aliskiren by underlying DM status (non-DM: HR: 1.17, 95% CI: 0.71-1.93; DM: HR: 2.39, 95% CI: 1.30-4.42; P = 0.07 for interaction). Conclusion This pre-specified subgroup analysis from the ASTRONAUT trial generates the hypothesis that the addition of aliskiren to standard HHF therapy in non-diabetic patients is generally well-tolerated and improves post-discharge outcomes and biomarker profiles. In contrast, diabetic patients receiving aliskiren appear to have worse post-discharge outcomes. Future prospective investigations are needed to confirm potential benefits of renin inhibition in a large cohort of HHF patients without D

Untying the Gordian knot of guilt and shame - The structure of guilt and shame reactions based on situation and person variation in Belgium, Hungary, and Peru

In this study, the structure of guilt and shame reactions are investigated in three cultural groups (Peru, Hungary, and Belgium) Using two newly Constructed scenario-based inventories. Results show that it is possible to distinguish between a structure Of guilt and shame reactions based on person variation and a structure based on situation variation. Moreover, both the person-based and the situation-based structures of shame and guilt are very similar across the three cultural groups, whereas within cultural groups, the two structures are quite different. The dimensions guilt versus shame and interpersonal versus intrapersonal orientation spanned the situation-based structure, whereas the dimensions control versus lack of control and appraisals versus subjective experiences and action tendencies spanned the person-based structure

Playing games with observation, dependency and agency in a new environment for making construals

© 2016 IEEE.Making construals is a new digital skill that complements conventional programming. Its primary focus is on using computer-related technology to stage interactive experience of unprecedented richness and subtlety. This paper is a tutorial on the latest version of an instrument for making construals developed in the ongoing EU Erasmus+ CONSTRUIT! project. Its principal theme is the re-creation of "the OXO laboratory" - an interactive environment in which variants of the game of noughts-and-crosses can be freely designed and evaluated

Chronic oral study of myosin activation to increase contractility in heart failure (COSMIC-HF): a phase 2, pharmacokinetic, randomised, placebo-controlled trial

Summary: Background: Impaired contractility is a fundamental abnormality in heart failure with reduced ejection fraction (HFrEF). We evaluated the pharmacokinetics of chronic therapy with the cardiac myosin activator omecamtiv mecarbil as well as its effect on cardiac function and structure in such patients. Methods: In this randomised, parallel-group, double-blind study, 448 patients from 87 sites in 13 countries with stable, symptomatic chronic heart failure and left ventricular ejection fraction ≤40% were randomly assigned (1:1:1) using an interactive web response system to oral omecamtiv mecarbil (25 mg twice daily; or 25 mg twice daily with pharmacokinetic-guided uptitration to 50 mg twice daily, PK-titration group) or placebo for 20 weeks. The primary endpoint was the maximal omecamtiv mecarbil plasma concentration (Cmax); secondary endpoints were changes from baseline in cardiac function and dimensions, heart rate and NT-proBNP at week 20. (ClinicalTrials.gov, NCT01786512) Findings: In patients enrolled from March 17, 2014 through March 5, 2015, Cmax (mean ± SD) at 12 weeks was 200±71 and 318±129 ng/mL in the 25 mg (n = 147) and PK-titration (n = 141) groups, respectively. Differences were seen in all secondary endpoints by 20 weeks in the PK titration group (n = 149) compared to placebo (n = 149): systolic ejection time [least square mean difference (95% CI); +25 (18, 32) msec, p<0·0001], stroke volume [+3·6 (0·5, 6·7) mL, p=0·0217], left ventricular end-systolic and end-diastolic dimensions [ 1·8 (-2·9, -0·6) mm, p=0·0027; 1·3 (-2·3, 0·3) mm, p=0·0128, respectively], heart rate [ 3·0 (-5·1, -0·8) bpm, p=0·0070] and NT-proBNP [ 970 (-1672, -268) pg/mL, p=0·0069). The maximum changes from baseline in plasma troponin-I concentrations were greater in patients assigned to omecamtiv mecarbil [PK titration: 0·020 ng/mL, (0·005, 0·038); median (Q1, Q3), p<0·0001] than placebo [0·010 ng/mL (0·000, 0·020)]. No important differences in adverse clinical events were observed. Interpretation: In patients with chronic HFrEF, pharmacokinetic-guided dosing of omecamtiv mecarbil achieved plasma concentrations associated with improvements in cardiac performance and ventricular dimensions

Making Construals as a New Digital Skill: Dissolving the Program - And the Programmer - Interface

© 2015 IEEE.Making a construal is a way of using the computer to help us in making sense of a situation. Its merits as a new digital skill for developing open educational resources in the constructionist tradition are illustrated using a basic construal of shopping activity. Making construals is the central theme of the three year EU Erasmus+ CONSTRUIT! project. This paper takes the form of an introductory tutorial highlighting key qualities of construals that will shape the CONSTRUIT! agenda