Search Results (15)

This study addresses recurring failures of a gas boiler with a steam capacity of 65,000 kg/h, which is operating in a Polish industrial plant. To determine the cause, material examinations were carried out, including chemical composition and microstructural analysis of SA178A steel, as well as strength tests. The results revealed no significant material degradation outside the cracking zones, suggesting that the failures were primarily caused by thermo-mechanical interactions. A finite element model in Ansys Workbench software was developed, incorporating thermal and mechanical boundary conditions, to reproduce the behavior of the critical section. The analysis demonstrated stress concentrations at the junction between the box and the membrane wall, resulting from large thermal displacement differences. The plastic strains under static loading do not exceed 5%, which implies that, without considering the cyclic nature of boiler operation, the wall should not experience failure. Analysis taking into account only 3 full operating cycles indicates a continuous increase in plastic deformation, which leads to the occurrence of ratcheting. To mitigate these effects, a modification of the sealing box design was proposed. Simulations indicated a reduction in plasticized zones by approximately 65%, and the effectiveness of the solution was confirmed by two years of failure-free operation. The findings highlight the importance of an integrated diagnostic, numerical, and design approach to improving boiler durability. Full article

Background/Objectives: Nurses play a vital role in healthcare, yet their demanding working conditions, including long hours, shift work, and stress, can negatively impact health behaviors. In Poland, empirical data on nurses’ eating habits and body composition remain limited. Therefore, this study aimed to evaluate body composition and dietary habits among nurses, and to identify significant relationships and associations between these variables. Methods: A cross-sectional observational study was conducted among 460 Polish nurses. The mean age of the respondents was 45.07 years (SD ± 11.98). Body composition was assessed using the Tanita MC-780 PLUS MA analyzer, and eating behaviors were measured with the standardized My Eating Habits questionnaire (MEH). Advanced statistical analyses including k-means clustering, ANOVA, chi-square tests, Spearman’s correlation, ROC curves, decision tree modeling, and heatmap visualization were used to identify associations. Results: The MEH scores among nurses indicated average eating behavior. However, excess body fat, overweight/obesity, shift work, and holding multiple jobs were significantly associated with emotional overeating, habitual overeating, and restrictive eating. Decision tree analysis identified Body Mass Index (BMI), fat-free mass (FFM) and comorbidities as key predictors of problematic eating patterns. Interaction effects showed that shift work combined with higher BMI further increased the risk of maladaptive behaviors. Heatmaps confirmed the strongest MEH scores in participants with elevated BMI and FFM. Conclusions: The findings underscore the need for targeted workplace interventions promoting healthy eating and weight control among nurses. Recognizing risk factors such as excess weight or multiple job holding can aid in designing effective prevention and health promotion strategies tailored to healthcare professionals. Full article

Carbohydrates have a dietary role, but excessive consumption of high-calorie sugars can contribute to an increased incidence of metabolic diseases and dental caries. Recently, carbohydrates with sweetening properties and low caloric value, such as D-tagatose, have been investigated as alternative sugars. D-tagatose is a rare sugar that has nutritional and functional properties of great interest for health. This literature review presents an approach to the biological effects of D-tagatose, emphasizing its benefits for oral health. Studies report that D-tagatose has antioxidant and prebiotic effects, low digestibility, reduced glycemic and insulinemic responses, and the potential to improve the lipid profile, constituting an alternative for diabetes mellitus and obesity. It can also be observed that D-tagatose has an antioxidant action, favoring the elimination of free radicals and, consequently, causing a reduction in cellular oxidative stress. Furthermore, it also has antibacterial potential against oral species. Regarding oral health, studies have shown that D-tagatose efficiently reversed bacterial coaggregations, including periodontopathogenic species, and impaired the activity and growth of cariogenic bacteria, such as S. mutans. D-tagatose significantly inhibited biofilm formation, pH decrease and insoluble glucan synthesis in S. mutans cultures. Salivary S. mutans counts were also significantly reduced by the consumption of chewing gum containing D-tagatose and xylitol. In addition, there is evidence that tagatose is effective as an air-polishing powder for biofilm decontamination. The literature indicates that D-tagatose can contribute to the prevention of systemic diseases, also constituting a promising agent to improve oral health. Full article

Electrolytic plasma polishing (EPPo) is an advanced metal surface finishing technology with high quality and environmental protection that has broad application prospects in the biomedical field. However, the effect of EPPo on surface properties such as corrosion resistance and the wettability of biomedical titanium alloys remains to be investigated. This paper investigated the changes in surface roughness, surface morphology, microstructure, and chemical composition of Ti6Al4V alloy by EPPo and their effects on surface corrosion resistance, wettability, and residual stress. The results showed that Ra decreased from 0.3899 to 0.0577 μm after EPPo. The surface crystallinity was improved, and the average grain size increased from 251 nm to more than 800 nm. The oxidation behavior of EPPo leads to an increase in surface oxygen content and the formation of TiO₂ and Al₂O₃ oxide layers. EPPo can significantly improve the corrosion resistance and wettability of titanium alloy in simulated body fluid and eliminate the residual stress on the sample surface. The surface properties are enhanced not only by the reduction in surface roughness but also by the formation of a denser oxide film on the surface, changes in the microstructure, an increase in surface free energy, and the annealing effect developed during EPPo. This study can provide guidance and references for applying EPPo to biomedical titanium alloy parts. Full article

Deterministic polishing based on jet electrochemical machining (Jet-ECM) is a stress-free machining method for low-rigidity and ultra-precision workpieces. The nozzle is equivalent to a special tool in deterministic polishing, and the workpiece material is removed using the mechanism of electrochemical dissolution at the position where the nozzle passes. By precisely regulating the nozzle’s movement speed and dwell time, the quantity of material removed from the workpiece at a designated position can be finely adjusted. With this mechanism, the improvement of the workpiece shape accuracy can be achieved by planning the nozzle trajectory and nozzle movement speed. However, due to the positioning errors of the polishing device, the actual position of the nozzle may deviate from the theoretical position, resulting in errors in material removal amount, which affects the accuracy and stability of the polishing process. This study established a mathematical model to analyze the influence of nozzle positioning errors in deterministic polishing based on Jet-ECM. This model has been used to design a specific deterministic polishing device based on Jet-ECM. With the proposed deterministic polishing device, the surface shape of the workpiece is converged. The surface peak-to-valley (PV) value of the φ 50 mm workpiece (valid dimensions = 90% of the central region) indicated that the shape error of the surface was reduced from 2.67 μm to 1.24 μm in 34 min. The power spectral density (PSD) method was used to evaluate the height distribution and height characteristics of the workpiece surface. The results show that the low frequency spatial error is reduced significantly after processing. This study improves the accuracy of the stress-free deterministic polishing methods and further expands the use of deterministic polishing in industry. Full article

Eicosanoids and other oxylipins represent a superfamily of bioactive lipids involved in the regulation of crucial biological processes such as inflammation, blood clotting or endothelial reactivity. Oxylipins are generated from polyunsaturated fatty acids (PUFAs) through various enzymatic and free-radical-mediated reactions. Interestingly, each metabolic step (PUFA availability, enzyme activity and oxidative stress) can be influenced by diet. Oxylipins could therefore be important mediators of the effects of diet on human health. To provide new insights into the relationships between oxylipins, fatty acids (FAs) and diet, we conducted two independent cohort studies nested in the Polish branch of the PURE international cohort and in the French Nutrinet-Santé cohort, respectively. The selected participants (n = 318) were healthy and fully characterized for their dietary intake. Our first objective was to determine if a healthy diet was associated with a specific oxylipin signature. Our secondary objective was to comprehensively investigate the relationships between diet, FAs and oxylipins. Participants were distributed into two groups according to the quality of their diet (based on the Alternative Healthy Eating Index (AHEI)). Targeted lipidomics was performed to comprehensively quantify plasma oxylipins and FAs. The association between oxylipins, FAs and the quality of the diet was modeled using conditional logistic regression. The relationships between oxylipins, FAs and diet were investigated using an unsupervised multiblock analysis (Multiblock Factorial Analysis (MFA)). We generated a unique database revealing unsuspected associations between diet, FAs and oxylipins. Validation studies are now required to further explore the potential of oxylipins to monitor the health effects of diet. Full article

This study analysed the condition of the surface layer of valve stems made of 317Ti steel after polishing and burnishing. Surface roughness, microhardness, and residual stress tests were carried out. The tests were carried out to determine the effect of the condition of the surface layer (especially non-standard parameters of surface roughness) of the stems on the durability of valves and to determine the possibility of obtaining a favourable state by means of sliding burnishing. Significant differences were observed in the values of the roughness parameters that determine the tribological properties of the surface, and higher surface microhardness and residual compressive stresses were obtained after burnishing. The durability of the stem-graphite seal in a reciprocating movement was tested, and the failure-free operation time of valves with burnished stems was approximately four times longer, which is the premise for recommending sliding diamond burnishing as a finishing treatment for valve stems. Full article

In the last 35 years Poland has undergone a series of fundamental economic, social, and biological transformations. With the transition from a centrally planned to a free-market economy, a period of economic and social transformation, Poland’s accession to the European Union, and the COVID-19 coronavirus pandemic, living conditions in the country have seen dramatic changes. The aim of this study was to assess whether there were changes in the basic health behaviors of Polish women, and if so, in what directions and with what strength, and whether there were differences in these changes depending on the socioeconomic status. Information on basic lifestyle factors (drinking alcohol, smoking, coffee drinking, and physical activity) and socioeconomic status (level of education, Gini coefficient, Gender Inequality Index, women total employment, employed women being in managerial positions, women among scientists) of 5806 women aged 40–50 years were analyzed. During the 1986–2021 period, based on the same methodology, team of technicians and research tools, six birth cohorts of women were examined in 1986, 1991, 1996, 2006, 2019 and 2021. Highly statistically significant changes were found in the frequencies of declared health behaviors from 1986–2021, according to the order of significance in coffee and alcohol consumption, physical activity levels, and smoking and smoking intensity. In subsequent cohorts, there were fewer and fewer women who did not drink coffee and alcohol, while more drank more than two cups of coffee a day and drank alcohol more often than 2× a week. Furthermore, they were more likely to be physically active, and slightly fewer were smokers. The lifestyles of the women were less likely to depend on their socio-economic status than the cohorts. In 1991 and 1996, there was a marked intensification of unhealthy behavior. Changes in the analyzed health behaviors may have been caused by adaptation to the high level of psychosocial stress observed during the transition of the 1986–2021 period and may result in changes in the biological condition and quality and length of life of Polish women. Research on social differences in health behavior provides an opportunity to analyze the biological effects of changes in the living environment. Full article

Selenium in the human body exhibits strong antioxidant and immunomodulatory properties. This bio-element is found in the active centers of antioxidant enzymes, which participate in the elimination of damage caused by free oxygen radicals. It enters into the composition of some proteins that build cell membranes, and performs stabilizing functions. Its involvement in catalyzing redox reactions helps reduce oxidative stress and potentially minimize ischemia–reperfusion damage in the kidney during ischemia. The aim of this study was to determine whether supplementation of preservative fluid with selenium in the presence of the antioxidant prolactin affects the levels of selected biochemical indices in homogenates of isolated porcine kidneys. The work is part of a series of our team studies to develop the optimal fluid composition for organ perfusion and preservation. Biolasol preservation fluid was modified by adding Se⁴⁺ (1 µg/L) and prolactin (0.1 µg/L). The study was conducted on 30 isolated kidneys of Polish Large White pigs. The kidneys were randomly divided into 3 groups (n = 10 in each) and were washed with preservative fluids: Biolasol control kidneys (C), Biolasol+Se (A1), Biolasol+Se+PRL (A2). After 48 h of preservation and perfusion, kidney sections were excised. Selected biochemical markers were determined in the tissue homogenates: protein and creatinine concentration. The study was performed in accordance with the recommendations of the II Local Ethics Commission for Animal Experiments in Cracow, Poland (number 1046/2013), and in accordance with the European Union Directive (EU guideline 93/119/EC). Supplementation of Biolasol solution with selenium and prolactin caused a statistically significant reduction in protein and creatinine levels compared to the control group in homogenates of isolated pig kidneys. Protein concentrations were: 2.5 ± 0.1 mg/g (group C) vs. 0.9 ± 0.2 mg/g (group A2) (p < 0.05), and creatinine concentrations were: 2.5 ± 0.1 mg/g (group C) vs. 1.9 ± 0.2 mg/g (group A2) (p < 0.05). In contrast, the use of selenium alone (without PRL shielding) resulted in a statistical increase in marker concentrations. Protein concentrations were 20% higher compared to Biolasol (p < 0.05), and creatinine concentrations were 16% higher compared to Biolasol (p < 0.05). Presumably, there was an accumulation of selenium in the organ, exacerbating the resulting damage. Selenium and prolactin added to Biolasol fluid show protective effects on nephrons. Selenium (IV) as a component of Biolasol solution adversely affects renal protection during ischemia. Full article

This project aims to recognize the school experiences of Polish students during the COVID-19 outbreak; we focused on the area of assessment of physical well-being and leisure time. Nearly two thousand primary or secondary school students aged 9 to 20 participated in the survey. Running descriptive statistics, frequency analysis, and significant difference tests, we found that 45% of students thought their physical well-being during the COVID-19 outbreak worsened compared to pre-pandemic times. Boys declared they felt better in their physical well-being than girls (p < 0.001). Most students noticed changes in the quality of their leisure time activities; boys were happier than girls in their free time during the outbreak (p < 0.001). Learners’ ages also differentiated the assessment of their physical well-being (p < 0.001) and leisure time (p < 0.001). The youngest students more often assessed their experiences in the researched fields as good or increased, while the older groups more often noticed a decrease. Multinomial logistic regression proved that the differences in the assessments of physical well-being and leisure time could be explained to the greatest extent by age and gender, whereas the place of residence and school location were insignificant. All in all, our study confirms the dominance of the adverse effects of the COVID-19 pandemic on physical well-being and changes in leisure time. As such, it is advisable (during and after outbreaks) to support children and adolescents by targeting individual and institution levels. We recommend developing techniques to reduce stress and information overload, increasing creative ways of spending leisure time, supporting families in navigating children’s free time, and expanding social support networks. Full article

Titanium Grade 4 (Ti G4) is widely used in medicine for dental implants. The failure-free life of implants depends on their properties such as resistance to wear and friction processes. This paper presents an analysis of the influence of sandblasting on tribological wear of commercial dental implants made of TiG4 in artificial saliva. Tribological wear measurements were performed in a reciprocating motion in the ball-on-disc system. The scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) method was used to characterize the surface of the implants before and after the tribological wear test. The microhardness of Ti G4 was measured before and after sandblasting by the Vickers method. The contact angle was determined by the method of sitting drop in air. The residual stress test using the X-Ray Diffraction (XRD) single-{hkl} sin²ψ method was carried out. The compressive residual stress of 324(7) MPa and surface hardening of Ti G4 was revealed after sandblasting with Al₂O₃ particles of 53–75 μm in diameter. It was found that sandblasting changes the surface wettability of Ti G4. The intermediate wettability of the mechanically polished surface and the hydrophobicity of the sandblasted surface was revealed. Sandblasting reduces the tribological wear and friction coefficient of Ti G4 surface in saliva. The three-body abrasion wear mechanism was proposed to explain the tribological wear of Ti G4 in saliva. Full article

The aim of the study was to determine whether experience related to horse age and number of starts in championships influences stress level, measured by salivary cortisol concentration. The study involved 18 clinically healthy Hucul mares who participated in the Polish Championships for Hucul Horses. Evaluation of performance value was carried out in accordance with the guidelines specified in the breeding and genetic resources conservation program for this breed. The championship lasted two days, consisting of conformation evaluation, endurance, and Hucul path. Saliva was collected at baseline (T1), after arena assessment (T2), after endurance (T3), and on the second day after the Hucul path (T4). Cortisol levels increased from an average of 2.73 ± 1.18 ng/mL (T1) to 10.46 ± 8.03 ng/mL after T3. Significantly lower levels of free cortisol were detected in the saliva of the younger mares, up to 9 years old, and mares who participated in only one qualifying path after each element of the championship. The highest levels of cortisol (T3) were found in mares competing repeatedly on the qualifying path. No correlation was found between cortisol levels and the championship results. Participation of mares in the championship was associated with stress, which was reflected in the increase in cortisol levels in saliva. Full article

Heat stress is one of the most critical factors affecting human life. In Central Europe, its influence is noticeable, especially in the Polish–Saxon region, which is a very popular tourist region also inhabited by a high number of elders. The main goal of this paper was to assess multi-annual changes in heat stress occurring in the region, considering the frequency of heat days, the UTCI (Universal Thermal Climate Index), and circulation conditions. The research showed that all the thermal and biothermal indices in this region significantly increased during 1971–2019 in the lowlands, the mountain foreland, and the lower mountain zone. In terms of the UTCI, a negative trend for cold stress frequency was noticed in the entire region in favor of an increase in a tendency toward thermoneutral conditions and heat stress. This concerns especially strong and very strong heat stress (UTCI > 32 °C), in which positive trends were observed for most of the stations located in the lower hypsometric zones. The results also showed that heat stress mainly occurs on days with anticyclonic circulation. Analysis of selected cases of heat waves in the 21st century indicated that the lower hypsometric zones are characterized by a very high UTCI, while the summit zone is free from heat stress occurrence. Full article

Propolis is a natural bee product with various beneficial biological effects. The health-promoting properties of propolis depend on its chemical composition, particularly the presence of phenolic compounds. The aim of this study was to evaluate the relationship between extraction solvent (acetone 100%, ethanol 70% and 96%) and the antifungal, antioxidant, and cytoprotective activity of the extracts obtained from propolis. Concentrations of flavonoids and phenolic acids in the propolis extracts were determined using ultrahigh-performance liquid chromatography. The antioxidant potential of different extracts was assessed on the basis of 2,2-diphenyl-1-picrylhydrazyl (DPPH·) free-radical-scavenging activity, Fe³⁺-reducing power, and ferrous ion (Fe²⁺)-chelating activity assays. The ability of the extracts to protect human red blood cell membranes against free-radical-induced damage and their antifungal activity was also determined. The results showed that the concentration of flavonoids in the propolis extracts was dependent on the solvent used in the extraction process and pinocembrin, chrysin, galangin, and coumaric acid were the most abundant phenols. All extracts exhibited high antioxidant potential and significantly protected human erythrocytes against oxidative damage. On the other hand, the antifungal activity of the propolis extracts depended on the solvent used in extraction and the fungal strains tested. It needs to be stressed that, to the best of our knowledge, there is no study relating the effect of solvent used for extraction of Polish propolis to its phenolic profile, and its antifungal, antioxidant, and cytoprotective activity. Full article

Hydride artefacts are commonly induced by the TEM sample preparation process in Zirconium alloys as hydrogen-sensitive metals, including electron polishing and focused ion beam (FIB) technology. In the research, we present the application of chemical polishing with a solution of 10HF:45HNO₃:45H₂O to prepare the disk samples for TEM observation in zirconium alloys. The thinning efficiency of chemical polishing is 25 μm per minute. XRD patterns indicate that the chemical polishing actually eliminates the macro- and micro-stress induced by mechanical grinding. TEM observation demonstrates that chemical polishing reduces the amount of hydride artefacts, especially hydrides with large size. It is proposed that induced stress provides driving force for hydride artefact formation. Compared with traditional mechanical grinding, the advantages of chemical polishing are high efficiency, free of induced stress, less induced hydride artefacts and bend contours. Full article