Tomas Bata University in Zlín
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In situ formed aldehyde-modified hyaluronic acid hydrogel with polyelectrolyte complexes of aldehyde-modified chondroitin sulfate and gelatin: An approach for minocycline delivery
Get PDFPolysaccharides like hyaluronan (HA) and chondroitin sulfate (CS) are native of the brain's extracellular matrix crucial for myelination and brain maturation. Despite extensive research on HA and CS as drug delivery systems (DDS), their high water solubility limits their application as drug carriers. This study introduces an injectable DDS using aldehyde-modified hyaluronic acid (HAOX) hydrogel containing polyelectrolyte complexes (PEC) formed with calcium, gelatin, and either CS or aldehyde-modified CS (CSOX) to deliver minocycline for Multiple Sclerosis therapy. PECs with CSOX enable covalent crosslinking to HAOX, creating immobilized PECs (HAOX_PECOX), while those with CS remain unbound (HAOX_PECS). The in situ forming DDS can be administered via a 20 G needle, with rapid gelation preventing premature leakage. The system integrates into an implanted device for minocycline release through either Fickian or anomalous diffusion, depending on PEC immobilization. HAOX_PECOX reduced burst release by 88 %, with a duration of 127 h for 50 % release. The DDS exhibited an elastic modulus of 3800 Pa and a low swelling ratio (0–1 %), enabling precise control of minocycline release kinetics. Released minocycline reduced IL-6 secretion in the Whole Blood Monocytes Activation Test, suggesting that DDS formation may not alter the biological activity of the loaded drug.European Union [813263]; Marie Curie Actions (MSCA) [813263] Funding Source: Marie Curie Actions (MSCA
Biodegradation of poly-3-hydroxybutyrate after soil inoculation with microbial consortium: Soil microbiome and plant responses to the changed environment
No full textBiodegradable plastics play a vital role in addressing global plastics disposal challenges. Poly-3-hydroxybutyrate (P3HB) is a biodegradable bacterial intracellular storage polymer with substantial usage potential in agriculture. Poly-3-hydroxybutyrate and its degradation products are non-toxic; however, previous studies suggest that P3HB biodegradation negatively affects plant growth because the microorganisms compete with plants for nutrients. One possible solution to this issue could be inoculating soil with a consortium of plant growth-promoting and N-fixing microorganisms. To test this hypothesis, we conducted a pot experiment using lettuce (Lactuca sativa L. var. capitata L.) grown in soil amended with two doses (1 % and 5 % w/w) of P3HB and microbial inoculant (MI). We tested five experimental variations: P3HB 1 %, P3HB 1 % + MI, P3HB 5 %, P3HB 5 % + MI, and MI, to assess the impact of added microorganisms on plant growth and P3HB biodegradation. The efficient P3HB degradation, which was directly dependent on the amount of bioplastics added, was coupled with the preferential utilization of P3HB as a carbon (C) source. Due to the increased demand for nutrients in P3HB-amended soil by microbial degraders, respiration and enzyme activities were enhanced. This indicated an increased mineralisation of C as well as nitrogen (N), sulphur (S), and phosphorus (P). Microbial inoculation introduced specific bacterial taxa that further improved degradation efficiency and nutrient turnover (N, S, and P) in P3HB-amended soil. Notably, soil acidification related to P3HB was not the primary factor affecting plant growth inhibition. However, despite plant growth-promoting rhizobacteria and N2-fixing microorganisms originating from MI, plant biomass yield remained limited, suggesting that these microorganisms were not entirely successful in mitigating the growth inhibition caused by P3HB.Ministry of Education, Youth and Sports of the Czech Republic; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Ministry of Agriculture of the Czech Republic, (MZE-RO1724, 90254)Ministry of Education, Youth and Sports of the Czech Republic [FCH-S-24-8591, 90254]; Ministry of Agriculture of the Czech Republic [MZE-RO1724
The impact of surface roughness on conformal cooling channels for injection molding
Get PDFInjection molding technology is widely utilized across various industries for its ability to fabricate complex-shaped components with exceptional dimensional accuracy. However, challenges related to injection quality often arise, necessitating innovative approaches for improvement. This study investigates the influence of surface roughness on the efficiency of conformal cooling channels produced using additive manufacturing technologies, specifically Direct Metal Laser Sintering (DMLS) and Atomic Diffusion Additive Manufacturing (ADAM). Through a combination of experimental measurements, including surface roughness analysis, scanning electron microscopy, and cooling system flow analysis, this study elucidates the impact of surface roughness on coolant flow dynamics and pressure distribution within the cooling channels. The results reveal significant differences in surface roughness between DMLS and ADAM technologies, with corresponding effects on coolant flow behavior. Following that fact, this study shows that when cooling channels’ surface roughness is lowered up to 90%, the reduction in coolant media pressure is lowered by 0.033 MPa. Regression models are developed to quantitatively describe the relationship between surface roughness and key parameters, such as coolant pressure, Reynolds number, and flow velocity. Practical implications for the optimization of injection molding cooling systems are discussed, highlighting the importance of informed decision making in technology selection and post-processing techniques. Overall, this research contributes to a deeper understanding of the role of surface roughness in injection molding processes and provides valuable insights for enhancing cooling system efficiency and product quality.Internal Grant Agency of Tomas Bata University in Zlin, (IGA/FT/2024/003)Internal Grant Agency of Tomas Bata University in Zli
The degradation of poly(1-butene) extrudates subjected to artificial and natural aging
Get PDFIn this work, we examined the degradation behavior of isotactic poly(1-butene) (PB-1) under artificial aging and natural weathering conditions. PB-1 samples underwent accelerated aging through UV irradiation and natural weathering. Chemical and structural changes in the degraded samples were characterized using Fourier-transform infrared–attenuated total reflectance (FTIR–ATR) spectroscopy, surface analysis, and wide-angle X-ray scattering (WAXS). The mechanical properties were evaluated via tensile testing. FTIR–ATR analysis revealed the presence of carbonyl groups in the degraded samples, indicating oxidative degradation. Surface observations employing scanning electron microscopy (SEM) revealed the formation of surface cracks in both samples, with differing crack initiation mechanisms. The two aging methods affected the mechanical properties of the samples: artificial aging induced a gradual reduction in both tensile modulus and strength, whereas natural weathering engendered a marginal increment in modulus alongside diminished strength. Additionally, elongation-at-break value witnessed a marked decrease in both sample sets during the preliminary stages of degradation. This work employed accelerated time equivalent, obtained by juxtaposition of the values of carbonyl index during both artificial aging and natural weathering and their interpolation to determine the degradation rate and adequately to correlate the final properties of the aged PB-1. It was observed that surface morphology and mechanical attributes of degraded samples were subject to additional influences such as temperature, humidity, and precipitation during natural weathering. This research work provided significant insights into PB-1 degradation mechanisms and effect of different aging conditions on its performance.National Technical Library in Prague, (IGA/FT/2023/008)IGA/FT/2023/008 [IGA/FT/2023/008
The specifics of the return of Czech tourism to the positives of the pre-COVID-19 era
Get PDFThe present study directs attention to the impact of the COVID-19 pandemic on one of the most complex and globally significant economic sectors, tourism. Significant losses in the tourism economy were also recorded in the Czech Republic, for which tourism was one of the most affected sectors. However, the pandemic also revealed the need to be prepared and have a plan to develop tourism effectively and to be able to solve unexpected problems. The question remains whether the Czech tourism industry managed to overcome the reflection of the impact of the pandemic in the critical year 2020 in continuity with a negative spillover into 2021 and subsequently build on the significantly positive development trend of the successful year 2019. A study based on a thorough comparison of secondary data, following on from the analysis of data from the Czech Statistical Office, presents not only a comprehensive reflection of the impact of the pandemic on tourism in connection with the specifics of the Czech environment but also points to a solution. The importance of tourism for the Czech economy is indisputable. Although it is a beneficial finding that "Czechs have rediscovered the Czech Republic," it is necessary to strengthen interest both on the part of foreign visitors (e.g., by satisfying the demand for specific topics such as food, events, LGBT tourism, etc.), and to gain the attention of investors and entrepreneurs
Service quality dimensions in Austrian food retailing – a text mining approach for physical retail stores
Get PDFInvestigating Service Quality (SQ) and its implications for customer satisfaction has become an increasingly popular research area. Especially in the context of physical grocery retailing, ensuring customer satisfaction has become a key success factor. Most previous research studies apply traditional methods (e.g. surveys) for physical shops and utilize text mining-based approaches mainly for e-commerce. In our paper, we propose a novel approach based on LDA. By combining expert-based word counting analysis with the LDA approach, we confirm that unsupervised text mining based on LDA can be used as a reliable approach to cluster textual comments to SQ dimensions in physical retail settings. We have analyzed over 163,000 publicly available textual customer reviews related to the Austrian market, which is special in terms of its extremely high density of retail outlets, high price levels and a tendency towards traditional form of shopping. Our results show that personal interaction, policies, and product-related aspects seem to be positive drivers of customer satisfaction, while reliability is a clear driver of customer dissatisfaction. Results also show a significantly higher relevance of personal interaction in smaller stores and cities with fewer than 5,000 inhabitants than in other store types and bigger cities. Regarding practical implications, hypermarkets should focus on physical aspects to reduce negative reviews and increase efforts in personal interaction to increase positive reviews. On the other hand, smaller stores should continue to rely on personal interaction to avoid negative reviews and might focus on higher reliability to generate more positive reviews. The applied text-mining approach enables future research with a starting base to analyze SQ dimensions and their relevance in additional countries or area, as e.g. fashion or hardware retail.Government of Upper Austria as part of the Excellence Network Logistics - Logistikum.RETAIL; Christian Doppler Research Association as part of the Josef Ressel Centre PREVAI
Greening the path: The three-way interactive effects of psychological ownership, green knowledge sharing, and social media
No full textThis study develops an integrated framework grounded in service-dominant logic theory to examine green destination psychological ownership, customer engagement, knowledge sharing, and social media usage as drivers of green electronic word of mouth. A multi-wave survey analysis conducted among 507 Vietnamese travelers supported the hypothesized direct effect, mediation, and three-way interaction between the factors. The results revealed that green customer engagement mediates the relationship between green destination psychological ownership and word of mouth. Additionally, companies’ green knowledge sharing and travelers’ social network proneness strengthen the positive influence of ownership feelings on engagement, subsequently enhancing word of mouth. The findings contribute novel insights into integrated green marketing effects, with implications for leveraging customer psychology and behaviors to promote green word of mouth. By fostering ownership feelings, actively sharing sustainability knowledge, and understanding social media habits, tourism organizations can enhance participation in green initiatives and recommendations. This study advances the theoretical and practical understanding of strategies for nurturing green behaviors and outcomes in the digital age through an integrated framework grounded in service-dominant logic theory. Further research should investigate additional variables and contexts to deepen knowledge on enabling collaborative value creation for sustainability.Hue University [DHH2023-06-129
Perception of sport, sports betting, and gambling from the point of view of university students – The case of the Czech Republic
No full textBACKGROUND: University students are one of the population groups that may be affected by the issue of sports betting and gambling.
AIM: The main aim of this paper was to discover the overall perception of university students in the Czech Republic of the issue of sports betting as one of the categories of gambling in the context of gender and biological age.
METHODS: The bibliographic and citation database Web of Science, and the citation and reference database Scopus were used to analyse secondary data. Selected mathematical and statistical methods were used for the analysis of primary data and information.
SAMPLE: The first research sample of respondents consisted of 391 university students in the Czech Republic who had experienced sports betting. The second sample comprised of 679 university students who had had no such previous experience.
RESULTS: The results have concluded that there is a relationship between the attitude towards sports betting, as one of the categories of gambling, and the gender, and the age of university students. Furthermore, it has been found that gender does not influence the perception of sports betting as gambling with the possibility of developing a potentially dangerous addiction, while the age of university students does have an effect on such perception.
CONCLUSIONS: A quick and easy way of funds acquisition, obtained from sports betting, was determined to be the most common factor intrinsically motivating and appealing to university students in the Czech Republic to participate in sports betting.FaME Tomas Bata University, (RVO/2022
The Czech Republic and non-governmental non-profit organizations after the impact of the COVID-19 crisis
Get PDFThe period of the pandemic crisis in the Czech Republic significantly reflected the uncertainty of the time. It was characterized by the loss of the guarantee for the services of non-governmental non-profit organizations, which the public will demand and accept in the future. The period coincided with financial impacts on the running of these organizations, declining public confidence, and declining interest from supporters. The presented study, based on the secondary and mainly primary data reflecting the attitude of non-governmental non-profit organizations of the Zlin Region based on quantitative research aimed at the communication of organizations during the pandemic, has once again confirmed the still-persistent shortcomings demonstrably requiring necessary changes leading to the efficiency of the current form of communication on a professional basis. One of the ways to offer a solution to the ongoing unhappiness is the intensive cooperation of non-governmental non-profit organizations with students of marketing communications, as documented explicitly by the collaboration of the Faculty of Multimedia Communications of the Tomas Bata University in Zlin in cooperation with the Zlin Region, which enables significant assistance in the professionalization of non-governmental non-profit organizations’ communication in continuity with development of the Zlin Region on the one hand. On the other hand, it strengthens the interest in non-commercial marketing among university students in continuity with their future professional classification
Sulfur and peroxide vulcanization of the blends based on styrene–butadiene rubber, ethylene–propylene–diene monomer rubber and their combinations
Get PDFRubber blends based on styrene–butadiene rubber, ethylene–propylene–diene monomer rubber and a combination of both rubbers were cured with different sulfur and peroxide curing systems. In sulfur curing systems, two type of accelerators, namely tetramethylthiuram disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, and combinations of both accelerators were used. In peroxide curing systems, dicumyl peroxide, and a combination of dicumyl peroxide with zinc diacrylate or zinc dimethacrylate, respectively, were applied. The work was aimed at investigating the effect of curing systems composition as well as the type of rubber or rubber combinations on the curing process, cross-link density and physical–mechanical properties of vulcanizates. The dynamic mechanical properties of the selected vulcanizates were examined too. The results revealed a correlation between the cross-link density and physical–mechanical properties. Similarly, there was a certain correlation between the cross-linking degree and glass transition temperature. The tensile strength of vulcanizates based on rubber combinations was higher when compared to that based on pure rubbers, which points out the fact that in rubber combinations, not only are the features of both elastomers combined, but improvement in the tensile characteristics can also be achieved. When compared to vulcanizates cured with dicumyl peroxide, materials cured with a sulfur system exhibited higher tensile strength. With the application of co-agents in peroxide vulcanization, the tensile strength overcame the tensile behavior of sulfur-cured vulcanizates.Agentúra na Podporu Výskumu a Vývoja, APVV, (APVV-19-0091, APVV-22-0011); Vedecká Grantová Agentúra MŠVVaŠ SR a SAV, VEGA, (1/0056/24)Slovak Research and Development Agenc