Repozytorium Uniwersytetu Śląskiego RE-BUŚ
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Investigation of Dry Sliding Friction, Wear and Mechanical Behavior of the Ti-6Al-7Nb Alloy after Thermal Oxidation
Full text linkThe mechanical and tribological characteristics of the Ti-6Al-7Nb alloy were investigated within a wide range of temperature and time parameters of thermal oxidation. The hardness, HIT, and indentation modulus, EIT, of the alloy in question, with and without an anti-wear oxide layer, were determined. The tribological properties of sliding couples were studied under technically dry friction conditions, using a ball-on-disc tribometer. The test pieces were non-oxidized and oxidized Ti-6Al-7Nb alloy discs, and Al2O3, ZrO2, and 100Cr6 balls were used as counter specimens. After thermal oxidation, the surface of the titanium alloy was characterized by a significantly higher hardness, HIT (8–10 GPa), compared to the surface not covered with oxide layers (3.6 GPa). The study showed that the curvature of the loading segments increased with an increasing oxidation temperature, indicating a strong positive dependence of hardness on the thermal oxidation temperature. The value of the indentation modulus, EIT, was also found to increase with the increasing oxidation temperature. The intensity of the tribological processes was strictly dependent on the oxidation parameters and the couple’s material (Al2O3, ZrO2, 100Cr6). It has been shown that the thermal oxidation process makes it possible to control, within a wide range, the friction-wear characteristics of the Ti-6Al-7Nb alloy
Humeral Capitellum Fractures in Adolescents: A Study of 6 Cases Treated by Open Reduction and Internal Fixation with Bioabsorbable Nails
Full text linkPurpose. The purpose of our study was to evaluate the clinical outcome following open reduction and internal fixation of humeral capitellum fractures in adolescents and to assess the usefulness of bioresorbable implants in that procedure. Due to the rarity of these fractures, there are not many studies dealing with the problem in the literature. Methods. We retrospectively evaluated a group of 6 skeletally immature patients aged 10.6–15.3 treated at our department from January 2015 to December 2021. Four type I and two type IV were diagnosed based on the Bryan and Morrey classification. Our patients underwent an open reduction and internal fixation of coronal shear fractures with the use of SmartNail®. Results. All patients were satisfied with the treatment outcome and had full pronation and flexion after surgery. Two patients presented minor deficits of extension and supination compared with the contralateral elbow. At the one-year follow-up, all patients scored 100 on the Mayo Elbow Performance Score. Conclusions. Correct diagnosis and early surgical intervention in humeral capitellum fractures are crucial. That fractures should be anatomically reduced with no articular cartilage damage in order to prevent osteoarthritis. Based on our experience, SmartNail® implant is accurate for the osteochondral fragment fixation
Comparison of Physicochemical, Mechanical, and (Micro-)Biological Properties of Sintered Scaffolds Based on Natural- and Synthetic Hydroxyapatite Supplemented with Selected Dopants
Full text linkThe specific combinations of materials and dopants presented in this work have not been previously described. The main goal of the presented work was to prepare and compare the different properties of newly developed composite materials manufactured by sintering. The synthetic-(SHAP) or natural- (NHAP) hydroxyapatite serves as a matrix and was doped with: (i) organic: multiwalled carbon nanotubes (MWCNT), fullerenes C60, (ii) inorganic: Cu nanowires. Research undertaken was aimed at seeking novel candidates for bone replacement biomaterials based on hydroxyapatite—the main inorganic component of bone, because bone reconstructive surgery is currently mostly carried out with the use of autografts; titanium or other non-hydroxyapatite -based materials. The physicomechanical properties of the developed biomaterials were tested by Scanning Electron Microscopy (SEM), Dielectric Spectroscopy (BSD), Nuclear Magnetic Resonance (NMR), and Differential Scanning Calorimetry (DSC), as well as microhardness using Vickers method. The results showed that despite obtaining porous sinters. The highest microhardness was achieved for composite materials based on NHAP. Based on NMR spectroscopy, residue organic substances could be observed in NHAP composites, probably due to the organic structures that make up the tooth. Microbiology investigations showed that the selected samples exhibit bacteriostatic properties against Gram-positive reference bacterial strain S. epidermidis (ATCC 12228); however, the property was much less pronounced against Gram-negative reference strain E. coli (ATCC 25922). Both NHAP and SHAP, as well as their doped derivates, displayed in good general compatibility, with the exception of Cu-nanowire doped derivates
Simple Rules for Complex Near-Glass-Transition Phenomena in Medium-Sized Schiff Bases
Full text linkGlass-forming ability is one of the most desired properties of organic compounds dedicated
to optoelectronic applications. Therefore, finding general structure–property relationships and
other rules governing vitrification and related near-glass-transition phenomena is a burning issue
for numerous compound families, such as Schiff bases. Hence, we employ differential scanning
calorimetry, broadband dielectric spectroscopy, X-ray diffraction and quantum density functional
theory calculations to investigate near-glass-transition phenomena, as well as ambient- and highpressure
molecular dynamics for two structurally related Schiff bases belonging to the family of
glycine imino esters. Firstly, the surprising great stability of the supercooled liquid phase is shown
for these compounds, also under high-pressure conditions. Secondly, atypical self-organization via
bifurcated hydrogen bonds into lasting centrosymmetric dimers is proven. Finally, by comparing the
obtained results with the previous report, some general rules that govern ambient- and high-pressure
molecular dynamics and near-glass transition phenomena are derived for the family of glycine imino
esters. Particularly, we derive a mathematical formula to predict and tune their glass transition
temperature (Tg) and its pressure coefficient (dTg/dp). We also show that, surprisingly, despite the
presence of intra- and intermolecular hydrogen bonds, van der Waals and dipole–dipole interactions
are the main forces governing molecular dynamics and dielectric properties of glycine imino esters
Health promoting schools and COVID-19: preparing for the future
No full textWe face an unprecedented period of history during which COVID-19 is clustered with other global conditions, such as obesity, undernutrition, an infodemic, and climate change. This syndemic (synergy of epidemics) calls for the development of children’s and youth’s health literacy and socioemotional skills, support for behavioural hygiene (e.g. washing hands, wearing masks), and adults’ responsibility and caring. Moreover, it calls for creating conditions for healthy living and learning for all and paying extra attention to inequalities that have increased during the pandemic. Today, more than ever, there is an essential demand for schools to create environments that maintain and promote health for all. Within this commentary, we argue that whole-school approaches, such as the health promoting school, are essential to fight against the pandemic and to
prepare schools for future challenges
Saint Joseph’s Foundation of the Polish Bishops’ Conference
No full textIn order to understand the need for the appointment, role and tasks of Saint Joseph’s Foundation of the Polish Bishops’ Conference (hereinafter referred as “Foundation”), it is necessary to present an outline of the context of its establishment which, in practice, means the history of the structural reactions of the Polish Church to cases of sexual abuse of minors and vulnerable persons by clergy or other persons officially connected with the institutions of the Polish Church (for example by vows, employment etc.). The turning point and actual
beginning of these activities was June 2013, when the Episcopal Conference of Poland appointed Father Adam Żak SJ to the position of the coordinator of the KEP (Episcopal Conference of Poland) for the protection of children and youth (Fragment tekstu)
Glioblastoma: Pitfalls and Opportunities of Immunotherapeutic Combinations
No full textGlioblastoma multiforme (GBM) is the most common and aggressive primary central nervous system tumour in adults. It has extremely poor prognosis since the current standard of care, comprising of gross total resection and temozolomide (TMZ) chemoradiotherapy, prolongs survival, but does not provide a durable response. To a certain extent, this is due to GBM's heterogeneous, hostile and cold tumour microenvironment (TME) and the unique ability of GBM to overcome the host's immune responses. Therefore, there is an urgent need to develop more effective therapeutic approaches. This review provides critical insights from completed and ongoing clinical studies investigating novel immunotherapy strategies for GBM patients, ranging from the use of
immune checkpoint inhibitors in different settings of GBM treatment to novel combinatorial therapies. In particular, we discuss how treatment regimens based on single antigen peptide vaccines evolved into fully personalised, polyvalent cell-based vaccines, CAR-T cell, and viral or gene therapies. Furthermore, the results of the most influential clinical trials and a selection of innovative preclinical studies aimed at activating the immunologically cold GBM microenvironment are reviewed
Design-based research of ESP/EAP materials : online courses for the MA and PhD students
No full textDesign-based research (DBR) involves developing materials based on a strong link
between research and educational practice. The paper aims to follow the DBR and describe
English for Specific Purposes (ESP) and English for Academic Purpose (EAP) online courses
presented for the MA and PhD students. The paper seeks to address two following questions:
What is the model of ESP online course for the MA students? What is the model of ESP online
course for the PhD students? The project will use the mixed type of research, including a questionnaire
study and self-reflection analysis. The results are hoped to bring practical implications
for further online courses developed at the university level. Design-based research (DBR) polegają na opracowywaniu materiałów
z uwzględnieniem silnego związku między badaniami a praktyką edukacyjną. Artykuł ma na
celu omówienie kursów online English for Specific Purposes (ESP) i English for Academic
Purposes (EAP), przygotowywanych dla studentów studiów magisterskich i doktoranckich
w odwołaniu do badań typu DBR. W artykule starano się odpowiedzieć na następujące pytania:
Jaki jest model kursu ESP online dla studentów studiów magisterskich? Jaki jest model
kursu ESP online dla doktorantów? Zaprezentowano mieszany typ badań, obejmujący badanie
ankietowe i analizę autorefleksji. Uzyskane wyniki mogą pomóc w opracowywaniu kolejnych
kursów online na poziomie uniwersyteckim
Accuracy of Code GNSS Receivers under Various Conditions
No full textThe main objective of this research work was to study the accuracy of GNSS code receivers
under poor sky visibility conditions based on measurements on three different objects (point, line, and
surface) and additionally to test results on point positioning with good sky visibility conditions. The
measurement was based on 3 smartphones (in the same mode to check repeatability) and 2 handheld
receivers (working in GPS+GLONASS modes). The methodology was based on the RTK technique,
whose coordinates were assumed as a reference. Based on the results, the significant influence of
measuring in the vicinity of high trees on the obtained accuracy was observed for both the precise
geodetic equipment and the tested code receivers. More favorable results of point positioning were
observed when using mobile phones. On the other hand, in the case of measurement in motion, the
handheld receivers guaranteed higher accuracy. Moreover, the study showed that handheld receivers
might achieve a better accuracy than smartphones, and that position might be determined with a
greater accuracy and reliability. Furthermore, handheld receivers were characterized by a smaller
number of outliers
Polyurethane-Based Porous Carbons Suitable for Medical Application
No full textThe main aim of the study was to synthesize and analyze spectral data to determine the structure and stereometry of the carbon-based porous material internal structure. Samples of a porous biomaterial were synthesized through anionic polymerization following our own patent and then carbonized. The samples were investigated using MALDI ToF MS, FTIR ATR spectroscopy, optic microscopy, SEM, confocal laser scanning microscopy and CMT imaging. The analysis revealed the chemical and stereological structure of the obtained porous biomaterial. Then, the parameters characterizing the pore geometry and the porosity of the samples were calculated. The developed material can be used to collect adsorption of breathing phase samples to determine the parity composition of exhaled air