The paper presents the results of application of a novel Barkhausen effect (BE) probe with adjustable magnetizing field direction for the stress level evaluation in ferromagnetic materials. The investigated sample was in a form of a pipe, made of P91 steel that was anisotropic due to the production process. The measurements were performed before and after welding, revealing the influence of welding process on the residual stress distribution. As was observed, the process introduced high tensile stresses in the normal to the weld direction (which can be interpreted as a decrease of strongly compressive residual stresses present in martensitic steels). In addition to that, the paper presents investigations of the measurement set performance corroborating its applicability for Barkhausen effect signal measurements in the magnetically anisotropic materials. The signals obtained during manual rotation of the probe (typical method of BE measurements) are very similar to those recorded during automatic field axis rotation.
In the design process of offshore steel structures, it is typical to employ commercial calculation codes in which simulation and evaluation of results are performed on the basis of the available standards (e.g. API, DNV, Lloyds). The modeling and solution rely on finite element methods and cover the simulation of the structure’s properties along with the influence of the marine environment – sea currents, wave and wind loading, as well as the influence of vibrations, buoyancy and accompanying mass of water. Both commercial and open source mathematical modeling software which is available nowadays allows for cost effective and flexible implementation of advanced models for offshore industrial structures with high level of credibility and safety. The models can be built to suit task-specific requirements and evaluated on the basis of the selected criterial system best suited to the needs of the customer. Examples of methodology for environmental and structural model development are presented, along with simulation results covering a wide scope of data, ranging from stress and deformation to resonant characteristics and issues of technological feasibility.
Alpha lipoic acid is an antioxidant substance used for the pathogenic treatment of diabetic neuropathy, oxidative stress being a central mechanism in diabetic microvascular complications. Our study included 24 diabetes mellitus patients with diabetic neuropathy and 20 healthy subjects. Diabetes patients were given alpha lipoic acid 600 mg intravenously for 10 days and then per os for 30 days.
Significant improvements were observed concerning oxidative stress evaluated by measuring serum malondyaldehide and ceruloplasmin. The clinical characteristic of neuropathy improved, both the level of pain decreased and the vibration perception threshold increased. Our study demonstrated a two times higher level of oxidative stress in patients with diabetes compared to healthy subjects, and that by influencing oxidative stress we could influence the clinical aspects of neuropathy. Further investigations need to be done to explore the pleiotropic effects of alpha lipoic acid on other mechanisms that are implicated in the pathogenies of diabetic neuropathy.
The investigation of plastic deformation and residual stress by non-destructive methods is a subject of large relevance for the industry. In this article, the difference between plastic and elastic deformation is discussed, as well as their effects on magnetic measurements, as hysteresis curve and Magnetic Barkhausen Noise. The residual stress data can be obtained with magnetic measurements and also by the hole drilling method and x-ray diffraction measurements. The residual stress level obtained by these three different methods is different, because these three techniques evaluate the sample in different depths. Effects of crystallographic texture on residual stress are also discussed. The magnetoelastic term should be included in micromagnetic methods for residual stress evaluation. It is discussed how the micromagnetic energy Hamiltonian should be expressed in order to evaluate elastic deformation. Plastic deformation can be accounted in micromagnetic models as a term that increases the coercive field in soft magnetic materials as the steels are.
Background and Aims: To assess the impact of 1 year administration of omega-3 fatty acids supplements on oxidative stress parameters and atherosclerosis progression. Material and Methods: A total of 284 patients with metabolic syndrome, aged 61±6.7 years, without clinical evidence of atherosclerosis were allocated to 2 groups, matched by sex and age: group A (140 patients) - diet according to ESC/EASD recommendations; group B (144 patients) - the same diet + capsules of fish oil (1g eicosapentanoic acid, 1g docosahexanoic acid, 0,1g a-tocopherol acetate). Body fat (BF) was measured by bioimpedance analysis. For oxidative stress evaluation we used the FormOx systems monitor on a blood drop and for progression of atherosclerosis the intima-media thickness (IMT) at common carotid artery. Patients were evaluated at baseline, after 6 months and 1 year. Results: IMT significantly decreased in group B vs group A at 1 year (p<0.0001) and was correlated with %BF (p<0.001), waist-to-hip ratio (WHR) (p=0.002), leptin (p< 0.001), adiponectin (p<0.05), leptin/adiponectin ratio (p< 0.001) and oxidative stress (p<0.001). Conclusions: One year administrations of omega-3 PUFA enriched diet reduces cardiovascular risk of metabolic syndrome patients, resulting in a significant decrease of oxidative stress and atherosclerosis progression.
Professional Stress and Health among Critical Care Nurses in Serbia
The aim of this study was to identify and analyse professional stressors, evaluate the level of stress in nurses in Intensive Care Units (ICU), and assess the correlation between the perception of stress and psychological and somatic symptoms or diseases shown by nurses. The research, designed as a cross-sectional study, was carried out in the Intensive Care Units (ICU), in health centres in Serbia. The sample population encompassed 1000 nurses. Expanded Nursing Stress Scale (ENSS) was used as the research instrument. ENSS revealed a valid metric characteristic within our sample population. Nurses from ICUs rated situations involving physical and psychological working environments as the most stressful ones, whereas situations related to social working environment were described as less stressful; however, the differences in the perception of stressfulness of these environments were minor. Socio-demographic determinants of the participants (age, marital status and education level) significantly affected the perception of stress at work. Significant differences in the perception of stressfulness of particular stress factors were observed among nurses with respect to psychological and somatic symptoms (such as headache, insomnia, fatigue, despair, lower back pain, mood swings etc.) and certain diseases (such as hypertension, myocardial infarction, stroke, diabetes mellitus etc). In view of permanent escalation of professional stressors, creating a supportive working environment is essential for positive health outcomes, prevention of job-related diseases and better protection of already ill nurses.
tific and technical quality of works prepared by PhD stu-
dents. Following young scientists were successful in the
1. Tibor Ižák, Institute of Physics AS of Czech Re-
public, Praha, Czech Republic Title: Diamond/GaN het-
erostructures: Stressevaluation from top- and cross-
sectional Raman measurements
2. Marek Pleva, Faculty of Mathematics, Physics and
Informatics, Comenius University in Bratislava, Slovakia
Title: Thermal stability and mechanical properties of Ti-
B-Si-N coatings prepared by magnetron sputtering
3. Kentaro Imamura
Disorders (PPD). This reflects growing evidence that chronic stress can alter nerve pathways in the brain. However, the phrase Stress-Related Illness remains preferred when communicating with patients. 2 The StressEvaluation There are five major types of stress to look for in patients with diagnostically unexplained symptoms. Suspicion of a link between any of these and the patient’s condition is stronger if a stress occurred just before symptoms began or is linked to flares of symptoms. You might also listen for clues that symptoms are highly unlikely to have an organic
, London, 1984, 214-219. KADUKOVA, J., KAVULICOVA J.: Phytoremediation and stress. Evaluation of heavy metal-induced stress in plants, New York, Nova Science Publishers, 2010, 134 pp. KÜPPER, H., SPILLER, M., KUPPER, F.C.: Photometric method fort he quantification of chlorophylls and their derivates in complex mixtures: Fitting with Gauss-peak spectra. Anal. Biochem., 286, 2000, 247-256. LEON, A.M., PALMA, J.M., CORPAS, F.J., GOMEZ, M., ROMERO-PUERTAS, M. C., CHATTERJEE, D., MATEOS, R.M., DEL RIO, L.A., SAND ALIO, L.M.: Antioxidative enzymes in cultivars of pepper plants