Catalogue Search | MBRL
Search Results Heading
Explore the vast range of titles available.
MBRLSearchResults
-
DisciplineDiscipline
-
Is Peer ReviewedIs Peer Reviewed
-
Item TypeItem Type
-
SubjectSubject
-
YearFrom:-To:
-
More FiltersMore FiltersSourceLanguage
Done
Filters
Reset
24
result(s) for
"Michałek, Aleksandra"
Sort by:
Artificial neural network tools for predicting the functional response of ultrafast laser textured/structured surfaces
by
Penchev, Pavel
,
Michalek, Aleksandra
,
Castellani, Marco
in
Artificial neural networks
,
CAE) and Design
,
Computer-Aided Engineering (CAD
2022
Artificial Neural Networks (ANNs) are well-established knowledge acquisition systems with proven capacity for learning and generalisation. Therefore, ANNs are widely applied to solve engineering problems and are often used in laser-based manufacturing applications. There are different pattern recognition and control problems where ANNs can be effectively applied, and one of them is laser structuring/texturing for surface functionalisation, e.g. in generating Laser-Induced Periodic Surface Structures (LIPSS). They are a particular type of sub-micron structures that are very sensitive to changes in laser processing conditions due to processing disturbances like varying Focal Offset Distance (FOD) and/or Beam Incident Angle (BIA) during the laser processing of 3D surfaces. As a result, the functional response of LIPSS-treated surfaces might be affected, too, and typically needs to be analysed with time-consuming experimental tests. Also, there is a lack of sufficient process monitoring and quality control tools available for LIPSS-treated surfaces that could identify processing patterns and interdependences. These tools are needed to determine whether the LIPSS generation process is in control and consequently whether the surface’s functional performance is still retained. In this research, an ANN-based approach is proposed for predicting the functional response of ultrafast laser structured/textured surfaces. It was demonstrated that the processing disturbances affecting the LIPSS treatments can be classified, and then, the surface response, namely wettability, of processed surfaces can be predicted with a very high accuracy using the developed ANN tools for pre- and post-processing of LIPSS topography data, i.e. their areal surface roughness parameters. A Generative Adversarial Network (GAN) was applied as a pre-processing tool to significantly reduce the number of required experimental data. The number of areal surface roughness parameters needed to fully characterise the functional response of a surface was minimised using a combination of feature selection methods. Based on statistical analysis and evolutionary optimisation, these methods narrowed down the initial set of 21 elements to a group of 10 and 6 elements, according to redundancy and relevance criteria, respectively. The validation of ANN tools, using the salient surface parameters, yielded accuracy close to 85% when applied for identification of processing disturbances, while the wettability was predicted within an r.m.s. error of 11 degrees, equivalent to the static water contact angle (CA) measurement uncertainty.
Journal Article
Comparative analysis of lumen enlargement mechanisms achieved with the bifurcation dedicated BiOSS® stent versus classical coronary stent implantations by means of provisional side branch stenting strategy: an intravascular ultrasound study
2013
The aim of this study was to analyze the mechanisms of lumen enlargement in bifurcation lesions, as assessed by intravascular ultrasound (IVUS), after percutaneous treatment with classic provisional “T” stenting with conventional drug-eluting stents (DES) versus bifurcation dedicated BiOSS
®
(Balton, Warsaw, Poland) stent. In this prospective study between Jan and Dec/11, 32 patients with single de novo coronary bifurcation lesions suitable for treatment with BiOSS stents were randomized (1:1). IVUS method included pre- and post-procedure analysis in the parent vessel. Vessel, lumen and plaque cross-sectional areas were determined at the target lesion [minimum lumen area (MLA) site], proximal limb, distal limb, and “window”—defined as the segment between the carina (flow divider) and the vessel wall at the level of the side branch inflow. All lesions were treated with provisional approach and only 1 case in BiOSS group had a stent implanted in the side branch. Angiographic and IVUS results including MLA at the target site and proximal/distal references were similar. However, mean window length—largest diameter within the window, was similar at baseline, but BiOSS measured significantly longer at postprocedure (2.21 ± 0.37 vs. 1.76 ± 0.52 mm,
p
= 0.01). In addition, the magnitude of changes in vessel (27 ± 24 % vs. 9 ± 10 %,
p
= 0.01) and plaque (2 ± 26 % vs. −2 ± 26 %,
p
= 0.02) areas at the window were significantly different for DES versus BiOSS groups, respectively. The contribution of vessel extension for lumen enlargement represented 54 versus 43 %, 130 versus 46 %, 98 versus 80 % and 51 versus 19 % of the result achieved at the proximal limb, window, distal limb and MLA sites for DES versus BiOSS, respectively; as for plaque re-distribution, results were 36 versus 57 %, −30 versus 54 %, 2 versus 20 %, and 49 versus 81 %, at the proximal limb, window, distal limb and MLA sites, respectively. These results suggest different mechanisms of lumen enlargement comparing conventional DES versus BiOSS dedicated bifurcation stent, which can impact side branch compromise during procedure.
Journal Article
Laser Induced Periodic Surfaces Structures : Advances in Modelling, Processing and Monitoring
by
Michalek, Aleksandra
in
Lasers
2022
Laser Induced Periodic Surface Structures (LIPSS) have been known to the scientific world for almost as long as the invention of first laser. The advantages of the ripples structures have been recognized soon after, which resulted in the development of many industrially fit applications because of the flexibility, environmental friendliness and robustness of the technology. Nonetheless, the important reason of the continuous growing interest in LIPSS is the great variety of functional responses that can be 'imprinted' on the surfaces, and thus be employed in many engineering fields. For the broader use of LIPSS treatments, specific industrial requirements and challenges still have to be addressed, especially associated with processing, modelling and monitoring. In this context, the research presented in this thesis focuses, firstly, on investigating the synergistic use of LIPSS with coatings for the purpose of combining the valuable surface properties without compromising on the functional performance. Next, the research addresses the issues of applying periodic structures on free form surfaces when the processing conditions vary. In particular, a predictive model is developed to account the effects from 3D processing disturbances hence minimizing the empirical research required to produce optimized structures for any given material and/or geometry. Subsequently, new approaches for ripples monitoring and process quality control are investigated. A light scattering method is proposed to satisfy the technical requirements of inline process monitoring with sufficient sensitivity to detect changes in LIPSS characteristics. Lastly, the use of artificial intelligence methods is considered for predicting the functional responses based on the topography data, also when the generation process is affected by the processing disturbances.
Dissertation
Adolescent well-being and learning in times of COVID-19—A multi-country study of basic psychological need satisfaction, learning behavior, and the mediating roles of positive emotion and intrinsic motivation
by
Spiel, Christiane
,
Toumazi, Toumazis
,
Lüftenegger, Marko
in
Adolescent
,
Adolescent Health - statistics & numerical data
,
Adolescent Health - trends
2021
The sudden switch to distance education to contain the outbreak of the COVID-19 pandemic has fundamentally altered adolescents’ lives around the globe. The present research aims to identify psychological characteristics that relate to adolescents’ well-being in terms of positive emotion and intrinsic learning motivation, and key characteristics of their learning behavior in a situation of unplanned, involuntary distance education. Following Self-Determination Theory, experienced competence, autonomy, and relatedness were assumed to relate to active learning behavior (i.e., engagement and persistence), and negatively relate to passive learning behavior (i.e., procrastination), mediated via positive emotion and intrinsic learning motivation. Data were collected via online questionnaires in altogether eight countries from Europe, Asia, and North America (N = 25,305) and comparable results across countries were expected. Experienced competence was consistently found to relate to positive emotion and intrinsic learning motivation, and, in turn, active learning behavior in terms of engagement and persistence. The study results further highlight the role of perceived relatedness for positive emotion. The high proportions of explained variance speak in favor of taking these central results into account when designing distance education in times of COVID-19.
Journal Article
Antioxidant defence and oxidative stress markers in cats with asymptomatic and symptomatic hypertrophic cardiomyopathy: a pilot study
by
Michałek, Marcin
,
Pasławska, Urszula
,
Tabiś, Aleksandra
in
antioxidant activity
,
Antioxidants
,
Antioxidative enzymes
2020
Background
Hypertrophic cardiomyopathy is the most common cardiovascular cause of death in cats. Although the majority of cats remain asymptomatic, some may develop signs of chronic heart failure due to diastolic failure, arterial thromboembolism (ATE) or sudden cardiac death. Therefore, it is crucial to identify individuals that are in high risk of developing cardiac complications before the onset of life-threatening signs. Oxidative stress is the imbalance between the production and neutralisation of reactive oxygen species. Uncontrolled reactive oxygen species overproduction leads to protein and lipid peroxidation and damages the DNA strands, injuring the cells and leading to their death. The aim of the study was to evaluate the oxidative state in cats with hypertrophic cardiomyopathy and healthy controls.
Results
In total, 30 cats divided into three groups were assessed: animals with clinically evident hypertrophic cardiomyopathy (HCM;
n
= 8), subclinical hypertrophic cardiomyopathy (SUB-HCM;
n
= 11) and healthy controls (
n
= 11). The activity of superoxide dismutase was statistically significantly lower in animals with symptomatic and asymptomatic hypertrophic cardiomyopathy (HCM 0.99 ± 0.35 U/mL; SUB-HCM 1.39 ± 0.4 U/mL) compared to healthy cats (2.07 ± 0.76 U/mL,
p
< 0.01). The activity of catalase was significantly lower in the SUB-HCM group (19.4 ± 4.2 nmol/min/mL) compared to the HCM (23.6 ± 5.9 nmol/min/mL) and the control (30 ± 7.5 nmol/min/mL,
p
< 0.01) group. The activity of glutathione peroxidase was 4196 ± 353 nmol/min/mL in the HCM group, 4331 ± 451 nmol/min/mL in the SUB-HCM group and 4037 ± 341 nmol/min/mL in the control group and did not differ significantly between groups. The total antioxidant capacity of plasma was 602 ± 65.5 copper reducing equivalents (CRE) in the HCM group, 605.9 ± 39.9 CRE in the SUB-HCM group and 629 ± 77.5 CRE in the healthy cats and did not differ significantly between the groups.
Conclusions
Activities of superoxide dismutase and catalase differed in cats with hypertrophic cardiomyopathy, however the activity of the latter was only significantly lower in asymptomatic stage of the disease. The potentially beneficial effect of antioxidative substances on the disease progression in the asymptomatic and symptomatic stage of this disease should also be examined.
Journal Article
Distance learning in higher education during COVID-19: The role of basic psychological needs and intrinsic motivation for persistence and procrastination–a multi-country study
2021
Due to the COVID-19 pandemic, higher educational institutions worldwide switched to emergency distance learning in early 2020. The less structured environment of distance learning forced students to regulate their learning and motivation more independently. According to self-determination theory (SDT), satisfaction of the three basic psychological needs for autonomy, competence and social relatedness affects intrinsic motivation, which in turn relates to more active or passive learning behavior. As the social context plays a major role for basic need satisfaction, distance learning may impair basic need satisfaction and thus intrinsic motivation and learning behavior. The aim of this study was to investigate the relationship between basic need satisfaction and procrastination and persistence in the context of emergency distance learning during the COVID-19 pandemic in a cross-sectional study. We also investigated the mediating role of intrinsic motivation in this relationship. Furthermore, to test the universal importance of SDT for intrinsic motivation and learning behavior under these circumstances in different countries, we collected data in Europe, Asia and North America. A total of N = 15,462 participants from Albania, Austria, China, Croatia, Estonia, Finland, Germany, Iceland, Japan, Kosovo, Lithuania, Poland, Malta, North Macedonia, Romania, Sweden, and the US answered questions regarding perceived competence, autonomy, social relatedness, intrinsic motivation, procrastination, persistence, and sociodemographic background. Our results support SDT’s claim of universality regarding the relation between basic psychological need fulfilment, intrinsic motivation, procrastination, and persistence. However, whereas perceived competence had the highest direct effect on procrastination and persistence, social relatedness was mainly influential via intrinsic motivation.
Journal Article
Serum total antioxidant capacity and enzymatic defence of dogs with chronic heart failure and atrial fibrillation: a preliminary study
by
Michałek, Marcin
,
Tabiś, Aleksandra
,
Noszczyk-Nowak, Agnieszka
in
antioxidant activity
,
Antioxidants
,
atrial fibrillation
2020
Atrial fibrillation may potentially contribute to oxidative stress to a greater extent than chronic heart failure. The aim of the study was to compare the serum total antioxidant capacity and enzymatic antioxidant defence of dogs with chronic heart failure and atrial fibrillation with those of subjects with chronic heart failure and sinus rhythm and healthy controls.A total of 33 dogs were divided into three groups: dogs with chronic heart failure and atrial fibrillation (CHF + AF; n = 12), chronic heart failure and sinus rhythm (CHF + SR; n = 9), and healthy controls (n = 12). Serum total antioxidant capacity (TAC), serum CuZn-superoxide dismutase (SOD) and catalase, and plasma glutathione peroxidase (GPx) activity were determined.SOD activity and serum TAC were significantly lower in the study groups than in control animals. Catalase activity was significantly higher and plasma GPx activity significantly lower in dogs with CHF + AF compared with the CHF + SR and control dogs.The results suggest that chronic heart failure in dogs significantly impacts the serum TAC and the antioxidant enzymatic defence, while plasma GPx activity is markedly lower in dogs with chronic heart failure and atrial fibrillation. The role of that imbalance needs further investigation.
Journal Article
Combined Application of Boron and Zinc Improves Seed and Oil Yields and Oil Quality of Oilseed Rape (Brassica napus L.)
by
Michałek, Sławomir
,
Safdar, Muhammad Ehsan
,
Elshikh, Mohamed S.
in
Agricultural production
,
agronomy
,
antioxidant enzymes
2023
Oilseed crops require several micronutrients to support their physiological functions and reproductive phases. A deficiency of these nutrients can significantly reduce the yield and oil quality of oilseed crops. Soil application of micronutrients can reduce their deficiency and improve plant growth, yield, and oil quality. Oilseed rape (Brassica napus L.) is an important oilseed crop that produces oil with low levels of saturated fat and high levels of beneficial omega-3 fatty acids, which renders it a widely used cooking oil. However, the yield and oil quality of oilseed rape are significantly affected by the deficiency of boron (B) and zinc (Zn). This two-year field study determined the influence of sole and combined soil application of B and Zn on the physiological attributes of plants, seed and oil yields, and oil quality under semiarid climatic conditions. Nine different B and Z combinations, i.e., B0 + Zn0 (control), B0 + Zn8, B0 + Zn10, B1 + Zn0, B1 + Zn8, B1 + Zn10, B2 + Zn0, B2 + Zn8, and B2 + Zn10 (kg ha−1), were included in the study. Sole and combined application of B and Zn significantly altered physiological attributes, seed and oil yields, and oil quality. The highest values for plant height, number of siliques per plant, number of seeds per silique, 1000-seed weight, seed and oil yields, oil quality (higher stearic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, and lower erucic acid), and physiological traits (protein concentration, soluble sugar concentration, chlorophyll concentration, photosynthesis and transpiration rates, and stomatal conductance) were recorded with the combined application of 2 + 8 kg ha−1 B and Zn, respectively, during both years of this study. The lowest values of yield- and oil-quality-related traits and physiological attributes were recorded for the control treatment. A dose-dependent improvement was recorded in B and Zn contents in leaves, and the highest values were recorded with the combined soil application of 2 + 10 kg ha−1 B + Zn, respectively. It can be concluded that 2 + 8 kg ha−1 B + Zn should be applied to oilseed rape for higher seed and oil yields and better oil quality under semiarid climatic conditions.
Journal Article
The impact of single nucleotide polymorphisms in MTHFR and MTRR genes on disease activity and the presence of methotrexate treatment side effects in children with juvenile idiopathic arthritis
by
Ryk, Aleksandra
,
Roszkiewicz, Justyna
,
Smolewska, Elzbieta
in
juvenile idiopathic arthritis
,
methotrexate
,
pharmacogenomics
2023
To determine the impact of single nucleotide polymorphisms (SNPs) in MTHFR and MTRR genes on disease activity and the presence of MTX therapy adverse events in Polish children with juvenile idiopathic arthritis (JIA).
SNP genotyping was performed using genomic DNA isolated from peripheral blood samples.
Patients with MTHFR rs1801133 CT/TT variant had higher values of inflammatory markers, number of joints with active arthritis, and JADAS-71 value at the baseline of MTX treatment. Children with MTRR rs1801394 AG/AA variant presented higher inflammatory marker values at JIA diagnosis.
MTHFR rs1801133 and MTRR rs1801394 polymorphisms are associated with higher disease activity at the moment of JIA diagnosis.
Journal Article
Design, Synthesis, and Development of Pyrazolo1,5-apyrimidine Derivatives as a Novel Series of Selective PI3Kδ Inhibitors: Part II—Benzimidazole Derivatives
by
Ochal, Zbigniew
,
Zygmunt, Beata
,
Banach, Martyna
in
5-benzimidazole-pyrazolo[1,5-a]pyrimidine
,
Alcohol
,
Amino acids
2022
Phosphoinositide 3-kinase (PI3K) is the family of lipid kinases participating in vital cellular processes such as cell proliferation, growth, migration, or cytokines production. Due to the high expression of these proteins in many human cells and their involvement in metabolism regulation, normal embryogenesis, or maintaining glucose homeostasis, the inhibition of PI3K (especially the first class which contains four subunits: α, β, γ, δ) is considered to be a promising therapeutic strategy for the treatment of inflammatory and autoimmune diseases such as systemic lupus erythematosus (SLE) or multiple sclerosis. In this work, we synthesized a library of benzimidazole derivatives of pyrazolo[1,5-a]pyrimidine representing a collection of new, potent, active, and selective inhibitors of PI3Kδ, displaying IC50 values ranging from 1.892 to 0.018 μM. Among all compounds obtained, CPL302415 (6) showed the highest activity (IC50 value of 18 nM for PI3Kδ), good selectivity (for PI3Kδ relative to other PI3K isoforms: PI3Kα/δ = 79; PI3Kβ/δ = 1415; PI3Kγ/δ = 939), and promising physicochemical properties. As a lead compound synthesized on a relatively large scale, this structure is considered a potential future candidate for clinical trials in SLE treatment.
Journal Article