Repozytorium Uniwersytetu Śląskiego RE-BUŚ
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The Influence of the Gradient Infill of PLA Samples Produced with the FDM Technique on Their Mechanical Properties
Full text linkThree-dimensional printing is a dynamically developing field of industry. Its main advantage
is the small amount of waste, no need to use specialized tools, and easy control of the mechanical
properties of the printed model. One of the most popular techniques of 3D printing is FDM. The
main factor influencing the mechanical properties of 3D-printed materials is the filling density. The
aim of this study was to determine the mechanical properties of porous structures with a porosity
gradient of PLA samples printed using the FDM technique. The accuracy of mapping the structures
by computed tomography was assessed, and then a static compression test was performed. It has
been shown that the strength properties increased with the increase in the filling density. The highest
value of compression strength, amounting to 41.2 MPa, was observed for samples made of PLA with
an 80% filling degree, whereas the lowest value of compression strength was found in PLA-T samples
with a filling degree of 10%, reaching only 0.6 MPa. It was found that not only the core filling density,
but also the outer layers, influences the mechanical properties. The assessment of spatial architecture
allowed for a qualitative and quantitative assessment. The obtained images from the computed
tomograph showed that the designed sample models were correctly reproduced in the entire volume
The Object Segmentation from the Microstructure of a FSW Dissimilar Weld
Full text linkFriction stir welding (FSW) is an environmentally friendly, solid-state welding technique.
In this research work, we analyze the microstructure of a new type of FSW weld applying a two- stage
framework based on image processing algorithms containing a segmentation step and microstructure
analysis of objects occurring in different layers. A dual-speed tool as used to prepare the tested weld.
In this paper, we present the segmentation method for recognizing areas containing particles forming
bands in the microstructure of a dissimilar weld of aluminum alloys made by FSW technology. A
digital analysis was performed on the images obtained using an Olympus GX51 light microscope.
The image analysis process consisted of basic segmentation methods in conjunction with domain
knowledge and object detection located in different layers of a weld using morphological operations
and point transformations. These methods proved to be effective in the analysis of the microstructure
images corrupted by noise. The segmentation parts as well as single objects were separated enough
to analyze the distribution on different layers of the specimen and the variability of shape and size of
the underlying microstructures, which was not possible without computer vision support
ARNI in HFrEFOne- Centre Experience in the Era before the 2021 ESC HF Recommendations
Full text linkBackground: Sacubitril/valsartan, an angiotensin receptor–neprilysin inhibitor (ARNI), has demonstrated a survival benefit and reduces heart failure hospitalization in patients with heart failure with reduced left ventricular ejection fraction (HFrEF); however, our experience in this field is limited. This study aimed to summarize a real clinical practice of the use of ARNI in HFrEF patients hospitalized due to HFrEF in the era before the 2021 ESC HF recommendations, as well as assess their clinical outcome with regard to ARNI administration. Methods and Materials: Overall, 613 patients with HFrEF hospitalized in 2018–2020 were enrolled into a retrospective one-centre cross-sectional analysis. The study population was categorized into patients receiving (82/13.4%) and not-receiving (531/82.6%) ARNI. Clinical outcomes defined as rehospitalization, number of rehospitalizations, time to the first rehospitalization and death from any cause were analysed in the 1–2 year follow-up in the ARNI and non-ARNI groups, matched as to age and LVEF. Results: Clinical characteristics revealed the following differences between ARNI and non-ARNI groups: A higher
percentage of cardiovascular implantable electronic devices (CIED) (p = 0.014) and defibrillators with
cardiac resynchronization therapy (CRT-D) (p = 0.038), higher frequency of atrial fibrillation (p = 0.002)
and history of stroke (p = 0.024) were in the ARNI group. The percentage of patients with HFrEF NYHA III/IV presented an increasing trend to be higher in the ARNI (64.1%) as compared to the non-ARNI group (51.5%, p = 0.154). Incidence of rehospitalization, number of rehospitalizations and time to the first rehospitalization were comparable between the groups. There were no differences between the numbers of deaths of any cause in the ARNI (28%) and non-ARNI (28%) groups. The independent negative predictor of death in the whole population of ARNI and non-ARNI groups was the coexistence of coronary artery disease (CAD) (beta= 0.924, HR 0.806, p = 0.011). Conclusions: Our current positive experience in ARNI therapy is limited to extremely severe patients with HFrEF. Regardless of the more advanced HF and HF comorbidities, the patients treated with ARNI presented similar mortality and rehospitalizations as the patients treated by standard therapy
Fe-Doped Barium Lanthanum Titanate as a Competitor to Other Lead- Free Piezoelectric Ceramics
Full text linkMultiferroic solid solutions of Ba1−xLaxTi1−x/4O3 and iron (BLFT) were synthesized using the conventional mixed oxide method. The dependence of the piezoelectric coefficients on Fe content in BLFT ceramics was determined by the quasi-static and resonance method. The results indicate that 0.3 mol% addition of Fe3+ ions to the ceramic structure increased the value of the piezoelectric parameter d33 to the maximum of 159 pC/N. This puts BLFT ceramics among other good-quality and lead-free piezoelectric ceramics. A major enhancement of dielectric properties related to the manipulation of Fe content in the barium lanthanum titanate (BLT) ceramics system is reported as well
What do people think about technological enhancements of human beings? An introductory study using the Technological Enhancements Questionnaire in the context of values, the scientistic worldview, and the accepted versions of humanism
Full text linkbackground
Rapid development of technologies increases the possibility
of technological enhancements of human beings, e.g., in
their cognitive skills or physical fitness. Attitudes towards
such enhancements may result in their social acceptance
or rejection.
participants and procedure
One hundred and thirty-nine young Polish adults participated
in the study. Participants completed the designed
Technological Enhancements Questionnaire (TEQ) and
questionnaires to measure values, the scientistic worldview,
and the accepted versions of humanism.
results
The study showed a one-dimensional TEQ structure and
its satisfactory reliability. Attitudes towards technological
enhancements correlated positively with achievement,
self-direction in thought, power over resources, the scientistic
worldview, and the evolutionary version of humanism.
They also correlated negatively with tradition and the
liberal version of humanism.
conclusions
The TEQ questionnaire is a short, reliable tool to measure
attitudes towards technological enhancements. This preliminary
study provided some significant results, but future
work to validate the questionnaire is needed
Selected physico-chemical properties of composite scaffolds of sintered submicrocrystalline corundum and bioglass
Full text linkPresented paper contains description and interpretation of the results of selected physicochemical and structural properties
of two types of composite sinters. They were constituted of a mixture of sintered microcrystalline corundum and bioglass
CaO-P2O5-SiO2-Na2O system intended for scaffolds to cell culture of human chondrocytes. The composites contained a mixture of both above-mentioned components in the volumetric proportion of 50:50 (W5) and 30:70 (W7). They were obtained
using powder metallurgy by free sintering in air atmosphere. Phase analysis of composites and verification of theoretical
identification using X-ray diffraction were performed. The same phases were found in both cases (Al2O3 SiO2 CaAl2Si2O8, Ca3 (PO4)2, Ca2Al4O7 and NaAlSiO4). Microscopic tests of composite surfaces were performed and some differences were
found. W5 sample was not completely covered with bioglass, whilst W7 sample was completely covered with bioglass with
few fine pores. Tests of surface topography confirmed the presence of large and small pores. Composite surfaces immersed
for 30 days in artificial blood plasma were tested and then electron microscopy analysis was performed. It was found that no
significant changes occurred on the surface of the W5 composite, probably partial corrosion of the glass happened. Spherical
forms characteristic of HA-hydroxyapatites were observed on the surface of sample W7. Human articular chondrocyte cells
were seeded on both types of sinters and proliferation assay was performed. Results indicate that tested scaffolds support
cellular attachment and proliferation of chondrocytes
Does age pay off? Effects of three-generational experiments of nanodiamond exposure and withdrawal in wild and longevity-selected model animals
No full textNanodiamonds (NDs) are considered a material with low toxicity. However, no studies describe the effects of ND
withdrawal after multigenerational exposure. The aim was to evaluate ND exposure (in the 1st and 2nd generations) effects at low concentrations (0.2 or 2 mg kg_ 1) and withdrawal (in the 3rd generation) in the wild (H) and longevity-selected (D) model insect Acheta domesticus. We measured selected oxidative stress parameters, immunity, types of cell death, and DNA damage. Most of the results obtained in the 1st generation, e.g., catalase (CAT), total antioxidant capacity (TAC), heat shock proteins (HSP70), defensins, or apoptosis level, confirmed no significant toxicity of low doses of NDs. Interestingly, strain-specific differences were observed. D-strain crickets reduced autophagy, the number of ROS+ cells, and DNA damage. The effect can be a symptom of mobilization of the organism and stimulation of physiological defense mechanisms in long-living organisms. The 2nd-generation D-strain insects fed ND-spiked food at higher concentrations manifested a reduction in CAT, TAC, early apoptosis, and DNA damage, together with an increase in HSP70 and defensins. ROS+ cells and cells with reduced membrane potential and autophagy did not differ significantly from the control. H-strain insects revealed a higher number of ROS+ cells and cells with reduced membrane potential, decreased CAT activity, and early apoptosis. Elimination of NDs from the diet in the 3rd generation did not cause full recovery of the measured parameters. We noticed an increase in the concentration of HSP70 and defensins (H-strain) and a decrease in apoptosis (D-strain). However, the most visible increase was a significant increase in DNA damage, especially in H-strain individuals. The results suggest prolonged adverse effects of NDs on cellular functions, reaching beyond “contact time” with these particles. Unintentional and/or uncontrolled ND pollution of the environment poses a new challenge for all organisms inhabiting it, particularly during multigenerational exposure
"Gustaw Herling-Grudziński. Między Wschodem a Zachodem" red. Grzegorz Przebinda, Bartosz Gołąbek, Wojciech Gruchała, Wydawnictwo Humanistyczne Pigonianum, Karpacka Państwowa Uczelnia w Krośnie, Krosno 2020 - recenzja
No full text"Setna rocznica urodzin Gustawa Herlinga-Grudzińskiego zrodziła potrzebę
dyskusji naukowych poświęconych wybitnemu pisarzowi i eseiście.
W 2020 roku ukazała się pokonferencyjna praca zbiorowa wydana przez
Karpacką Państwową Uczelnię im. Stanisława Pigonia w Krośnie. Spójne tematycznie
opracowanie naukowe biografii i twórczości prozaika problematyzuje
dokonania pisarza w perspektywie formowania współczesnej tożsamości
Europy między Wschodem a Zachodem." (fragm.
Efficient automatic 3D segmentation of cell nuclei for high-content screening
No full textBackground: High-content screening (HCS) is a pre-clinical approach for the assessment
of drug efficacy. On modern platforms, it involves fluorescent image capture
using three-dimensional (3D) scanning microscopy. Segmentation of cell nuclei in 3D
images is an essential prerequisite to quantify captured fluorescence in cells for screening.
However, this segmentation is challenging due to variabilities in cell confluency,
drug-induced alterations in cell morphology, and gradual degradation of fluorescence
with the depth of scanning. Despite advances in algorithms for segmenting nuclei for
HCS, robust 3D methods that are insensitive to these conditions are still lacking.
Results: We have developed an algorithm which first generates a 3D nuclear mask in
the original images. Next, an iterative 3D marker-controlled watershed segmentation
is applied to downsized images to segment adjacent nuclei under the mask. In the
last step, borders of segmented nuclei are adjusted in the original images based on
local nucleus and background intensities. The method was developed using a set of 10
3D images. Extensive tests on a separate set of 27 3D images containing 2,367 nuclei
demonstrated that our method, in comparison with 6 reference methods, achieved
the highest precision (PR = 0.97), recall (RE = 0.88) and F1-score (F1 = 0.93) of nuclei
detection. The Jaccard index (JI = 0.83), which reflects the accuracy of nuclei delineation,
was similar to that yielded by all reference approaches. Our method was on average
more than twice as fast as the reference method that produced the best results.
Additional tests carried out on three stacked 3D images comprising heterogenous
nuclei yielded average PR = 0.96, RE = 0.84, F1 = 0.89, and JI = 0.80.
Conclusions: The high-performance metrics yielded by the proposed approach suggest
that it can be used to reliably delineate nuclei in 3D images of monolayered and
stacked cells exposed to cytotoxic drugs
Safety and Work Organization Management in the Early Days of the COVID-19 Pandemic in the Lignite Mining and Energy Sector in Poland
No full textThe paper presents the results of sociological qualitative research on safety management
in work organization. The focus was on how to adapt the workforce to the sanitary regime during
the time of the COVID-19 pandemic in the lignite mining and energy sector in the Bełchatów poviat
(Łódź voivodeship, Poland). The study aimed to identify the dimensions of safety and the work
culture created in crisis conditions as perceived by workers. Based on the conducted analysis, the
process of adapting employees to the new rules of work organization was reported, including the
transition from fear and anxiety to control over threats and negative emotions. The essence of the
research was to support institutional memory to consolidate the existing knowledge and use it in
the future