Some aspects of physical metallurgy of microalloyed steels

Some aspects of deformation, precipitation, and recrystallization behavior in medium carbon V-microalloyed and low carbon Nb/Ti-microalloyed steels are presented in the paper. Changes in microstructure are explained together with methods of quantification. The temperature of No-recrystallization (Tnr) is defined as a milestone to show the onset of retardation of recrystallization while the apparent activation energy for hot working shows the extent of this retardation. In the case of high cooling rates, this method is not sufficiently sensitive and Trl (recrystallization limit temperature) and Trs (recrystallization stop temperature) must be evaluated from softening data. Paper presented the possibility to estimate Tnr temperature on six stands finishing train at Hot Strip Mill in HBIS Iron and Steel Serbia, Smederevo as well as the activation energy for static recrystallization, QSRX, derived from Tnr temperatures

The development and appraisal of a tool designed to find patients harmed by falsely labelled, falsified (counterfeit) medicines.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesFalsely labelled, falsified (counterfeit) medicines (FFCm's) are produced or distributed illegally and can harm patients. Although the occurrence of FFCm's is increasing in Europe, harm is rarely reported. The European Directorate for the Quality of Medicines & Health-Care (EDQM) has therefore coordinated the development and validation of a screening tool.The tool consists of a questionnaire referring to a watch-list of FFCm's identified in Europe, including symptoms of their use and individual risk factors, and a scoring form. To refine the questionnaire and reference method, a pilot-study was performed in 105 self-reported users of watch-list medicines. Subsequently, the tool was validated under "real-life conditions" in 371 patients in 5 ambulatory and in-patient care sites ("sub-studies"). The physicians participating in the study scored the patients and classified their risk of harm as "unlikely" or "probable" (cut-off level: presence of ≥2 of 5 risk factors). They assessed all medical records retrospectively (independent reference method) to validate the risk classification and documented their perception of the tool's value.In 3 ambulatory care sites (180 patients), the tool correctly classified 5 patients as harmed by FFCm's. The positive and negative likelihood ratios (LR+/LR-) and the discrimination power were calculated for two cut-off levels: a) 1 site (50 patients): presence of two risk factors (at 10% estimated health care system contamination with FFCm's): LR + 4.9/LR-0, post-test probability: 35%; b) 2 sites (130 patients): presence of three risk factors (at 5% estimated prevalence of use of non-prescribed medicines (FFCm's) by certain risk groups): LR + 9.7/LR-0, post-test probability: 33%. In 2 in-patient care sites (191 patients), no patient was confirmed as harmed by FFCm's. The physicians perceived the tool as valuable for finding harm, and as an information source regarding risk factors.This "decision aid" is a systematic tool which helps find in medical practice patients harmed by FFCm's. This study supports its value in ambulatory care in regions with health care system contamination and in certain risk groups. The establishment of systematic communication between authorities and the medical community concerning FFCm's, current patterns of use and case reports may sustain positive public health impacts.EDQ

Hematological and Biochemical Parameters in Elite Soccer Players during A Competitive Half Season

Background: The purpose of the present study was to report and discuss the hematological and biochemical behavior of elite soccer players, in order to get more insight in the physiological characteristics of these sportsmen and to provide trainers and sports doctors with useful indicators. Methods: Nineteen male soccer players volunteered to participate in this study. We followed the young elite soccer players during a competitive half season. Venous blood samples were collected between 9:00 and 10:00 a.m. after an overnight fast (10 h) at baseline, after 45 and 90 days and hematological and biochemical parameters were measured. Results: Hemoglobin and hematocrit levels were significantly reduced over the observational period (p lt 0.05), but erythrocyte count and iron levels remained unchanged. Bilirubin and ferritin levels significantly increased in response to regular soccer training (p lt 0.05). We observed a significant decrease in muscle enzyme plasma activity during the 90 days study period. ANOVA analysis revealed a significant increase in the leukocyte and neutrophil counts (p lt 0.05), in parallel with a significant decrease in the lymphocyte count (p lt 0.05) after the observational period of 90 days. Conclusions: Elite soccer players are characterized by significant changes in biochemical and hematological parameters over the half season, which are linked to training workload, as well as adaptation induced by the soccer training. Although the values of the measured parameters fell within the reference range, regular monitoring of the biochemical and hematological parameters is fundamental for the identification of a healthy status and related optimal performances by sport doctors and trainers and selection of a correct workload by trainers

Lactobacillus helveticus lafti l10 supplementation modulates mucosal and humoral immunity in elite athletes: a randomized, double-blind, placebo-controlled trial

To test the influence of probiotic supplementation on humoral immune response, a double-blind, placebo-controlled trial was conducted. Thirty athletes (24 males and 6 females, females: (V)over dotO(2)max 38.2 +/- 4.9 ml.kg(-1).min(-1), age 23.2 +/- 1.4 years; males: (V)over dotO(2)max 57.5 +/- 9.2 ml.kg(-1).min(-1), age 24.0 +/- 2.4 years, mean +/- SD) were randomized either to the probiotic group (Lactobacillus helveticus Lafti L10, 2 x 10(10) colony-forming units) or to the placebo group. Serum and saliva samples were collected at the baseline and after 14 weeks. Total and specific antibacterial antibody levels of IgM, IgG, and IgA classes were determined for different bacteria in the serum, and in saliva, total and specific antibacterial IgA levels were examined. Total IgM was elevated in both probiotic (18%, 15-20%; mean, 90% confidence interval; p = 0.02) and placebo group (35%, 22-47%; p = 0.02), without observed differences in changes between the groups. No significant changes in IgM levels specific for tested bacteria were found. Total IgG level was constant in both groups. A significant (16%, 22.8 to 35%, p = 0.04) reduction of anti-Enterococcus faecalis IgG was noted in the placebo group, in comparison with the probiotic group. There was a substantial decrease in total IgA level in the placebo group, when measured either in serum (15%, 12-18%, p = 0.04) or in saliva (35%, -1.4 to 53%, p = 0.03). Significantly reduced levels of serum anti-lactic acid bacteria IgA antibodies in the placebo group compared with the probiotic group were detected for Lactobacillus rhamnosus LA68 (24%, 5.8-42%, p = 0.02) and for L. rhamnosus LB64 (15%, 2.7-27%, p = 0.02). Probiotic administration could have beneficial effects on systemic humoral and mucosal immune responses

Effect of combined antioxidant treatment on oxidative stress, muscle damage and sport performance in female basketball players

Introduction/Objective We determined the impact of antioxidant supplementation by GE132® on sports performance, oxidative stress markers, and muscle enzymes activities in professional female basketball players. Methods Repetitive strength, explosive power, anaerobic endurance, and agility performance were measured before/after the 45-day supplementation period. The FORT (Free Oxygen Radicals Test) and FORD analysis (Free Oxygen Radical Defense) were assessed before/after basketball specific exercise bout, at the beginning/end of observational period. The grade of muscle damage was evaluated by aspartate aminotransferase (AST), creatine kinase (CK) and lactate dehydrogenase (LDH). Results After supplementation period, significant difference was not recorded regarding the basic motor skills tests. Basketball specific exercise bout induced significant increase in FORT (p < 0.05) only at the beginning of supplementation period. Both FORT and FORD significantly decreased over the observational period (p < 0.001, p < 0.01, respectively). CK and LDH were remarkably lower at the end of observational period (p < 0.05), compared to the baseline. Conclusion Exogenous supplementation with protective nutraceuticals such as those found in GE132®, could reduce acute/chronic oxidative stress and muscle damage, but had no effect on sport performance in basketball players. © 2019, Serbia Medical Society. All rights reserved

Effects of Probiotic Supplementation on Selected Parameters of Blood Prooxidant-Antioxidant Balance in Elite Athletes: A Double-Blind Randomized Placebo-Controlled Study

A randomized, double-blind, placebo-controlled study was conducted, in order to evaluate if Lactobacillus helveticus Lafti (R) L10 (Lallemand Health Solutions, Montreal, Canada) supplementation during three months could influence oxidative markers in the population of elite athletes: triathletes, cyclists and endurance athletes. Twenty-two elite athletes were randomized to either placebo (n = 12) or probiotic (n = 10) groups. The probiotic group received 2x1010 colony forming units of Lafti (R) L10. Before and after the supplementation serum samples were collected. Markers of oxidative stress and anti-oxidative defense: superoxide dismutase (SOD), paraoxonase (PON), advanced oxidation protein products (AOPP), malondialdehyde (MDA), total antioxidant status, total oxidant status, prooxidant-antioxidant balance, oxidative stress index, bilirubin, uric acid and albumin were determined in serum. Parameters of lipid status, as well as susceptibility to copper-induced oxidation of LDL particles in vitro were also determined. There was a significant interaction effect for MDA (p = 0.039), with a decrease in MDA in the probiotic group only (p = 0.049). There was a significant interaction effect for AOPP (p = 0.037), with a significant decrease in the probiotic group (p = 0.045). Interaction effect for SOD was approaching to formal significance (p = 0.108) and the post-hoc test showed a significant decrease in the probiotic group (p = 0.041) only. A significant correlation between AOPP and SOD (p = 0.012, r = -0.40) was found in the probiotic group at the end of the study. PON1 activity was decreased in both the probiotic (p = 0.032) and placebo group (p = 0.035). No significant changes in the remainder of the evaluated parameters were noted. In conclusion, probiotic strain Lafti (R) L10 exerts certain antioxidant potential, but further research is needed

Structure and Strength of Isothermally Heat-Treated Medium Carbon Ti-V Microalloyed Steel

Isothermal transformation characteristics of a medium carbon Ti-V microalloyed steel were investigated using light microscopy, scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and by uniaxial compressive testing. Samples austenitized on 1100 degrees C were isothermally treated in the range from 350 to 600 degrees C and subsequently water quenched. The final microstructure of the samples held at 350 degrees C consisted of bainitic sheaves and had compressive yield strength, approximately from 1000 MPa, which is attributed to high dislocation density of low bainite. At 400 and 450 degrees C, acicular ferrite became prevalent in the microstructure. It was also formed by a displacive mechanism, but the dislocation density was lower, leading to a decrease of compressive yield strength to approximately 700 MPa. The microstructure after the heat treatment at 500 degrees C consisted of coarse non-polygonal ferrite grains separated by pearlite colonies, principally dislocation free grains, so that the compressive YS reached a minimum value of about 700 MPa. The microstructure of the samples heat-treated at 550 and 600 degrees C consisted of pearlite and both grain boundary and intragranular ferrite, alongside with some martensite. After 600 s, austenite became stable and transformed to martensite after water quenching. Therefore, the presence of martensite increased the compressive YS to approx. 800 MPa

Cleavage Fracture of the Air Cooled Medium Carbon Microalloyed Forging Steels with Heterogeneous Microstructures

Cleavage fracture of the V and Ti-V microalloyed forging steels was investigated by the four-point bending testing of the notched specimens of Griffith-Owen’s type at −196◦ C, in conjunction with the finite element analysis and the fractographic examination by scanning electron microscopy. To assess the mixed microstructure consisting mostly of the acicular ferrite, alongside proeutectoid ferrite grains and pearlite, the samples were held at 1250◦ C for 30 min and subsequently cooled instill air. Cleavage fracture was initiated in the matrix under the high plastic strains near the notch root of the four-point bending specimens without the participation of the second phase particles in the process. Estimated values of the effective surface energy for the V and the Ti-V microalloyed steel of 37 Jm−2 and 74 Jm−2, respectively, and the related increase of local critical fracture stress were attributed to the increased content of the acicular ferrite. It was concluded that the observed increase of the local stress for cleavage crack propagation through the matrix was due to the increased number of the high angle boundaries, but also that the acicular ferrite affects the cleavage fracture mechanism by its characteristic stress–strain response with relatively low yield strength and considerable ductility at −196◦ C

Physical simulation of finish rolling of microalloyed steels in isothermal conditions

The aim of this work was to establish a temperature of finish rolling stage of Nb/Ti microalloyed steel containing 0.06 wt.% C, 0.77 wt.% Mn, 0.039 wt.% Nb and 0.015 wt.% Ti, using physical simulation. Samples were subjected to laboratory simulation at a twist plastometer at high temperatures, i.e. between 825 and 950 °C. Five pass deformation and interpass times were selected in accordance with a processing parameters at five stand finishing hot strip mill. Restoration (recovery and/or recrystallization) behavior was evaluated by calculation of Fraction Softening (FS) and Area Softening Parameter (ASP) values. At 950 °C all individual pass stress-strain curves, FS and ASP show full recrystallization in all interpass intervals. On the other hand, with a decrease in temperature to the interval of 875-825 °C, the extent of restoration is decreasing, leading to recovery as a sole softening mechanism at 825 °C, which was confirmed by the stress-strain curve shape, and values of FS and ASP. It is assumed that, due to high supersaturation, strain-induced precipitation promoted pinning of grain and subgrain boundaries and suppressed recrystallization. Therefore, the critical temperature for finish rolling was estimated to be 825 °C

Effect of astaxanthin supplementation on muscle damage and oxidative stress markers in elite young soccer players

Aim. The purpose of the current study was to examine the effect of Astaxanthin (Asx) supplementation on muscle enzymes as indirect markers of muscle damage, oxidative stress markers and antioxidant response in elite young soccer players. Methods. Thirty-two male elite soccer players were randomly assigned in a double-blind fashion to Asx and placebo (P) group. After the 90 days of supplementation, the athletes performed a 2 hour acute exercise bout. Blood samples were obtained before and after 90 days of supplementation and after the exercise at the end of observational period for analysis of thiobarbituric acid-reacting substances (TBARS), advanced oxidation protein products (AOPP), superoxide anion (O-2(center dot-)), total antioxidative status (TAS), sulphydril groups (SH), superoxide-dismutase (SOD), serum creatine kinase (CK) and aspartate aminotransferase (AST). Results. TBARS and AOPP levels did not change throughout the study. Regular training significantly increased O-2(center dot-) levels (main training effect, P lt 0.01). O-2(center dot-) increased after the soccer exercise (main exercise effect, P lt 0.01), but these changes reached statistical significance only in the P group (exercise x supplementation effect, P lt 0.05). TAS levels decreased significantly post- exercise only in P group (P lt 0.01). Both Asx and P groups experienced increase in total SH groups content (by 21% and 9%, respectively) and supplementation effect was marginally significant (P=0.08). Basal SOD activity significantly decreased both in P and in Asx group by the end of the study (main training effect, P lt 0.01). All participants showed a significant decrease in basal CK and AST activities after 90 days (main training effect, P lt 0.01 and P lt 0.001, respectively). CK and AST activities in serum significantly increased as result of soccer exercise (main exercise effect, P lt 0.001 and P lt 0.01, respectively). Postexercise CK and AST levels were significantly lower in Asx group compared to P group (P lt 0.05) Conclusion. The results of the present study suggest that soccer training and soccer exercise are associated with excessive production of free radicals and oxidative stress, which might diminish antioxidant system efficiency. Supplementation with Asx could prevent exercise induced free radical production and depletion of non-enzymatic antioxidant defense in young soccer player