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Synthesis and properties of fluorenyl- and carbazolylchromophores-containing organic semiconductors for perovskite and antimony sulfide solar cells.
No full textThe Sun is the most powerful, unlimited, and free-of-charge energy source available to humankind, and, every year, large amounts of solar energy reach the Earth. For over 70 years, the solar cells technology has enabled consumers to produce energy in sustainable ways. Currently, Silicon solar cells are the most popular and most readily commercially available option. Nevertheless, their production is difficult due to the need for expensive raw materials and high energy consumption. To address these issues, scientists are exploring alternative options including hybrid solar cells made from organic and inorganic materials. One promising technology is perovskite solar cells which have the potential to reduce the cost of solar energy. PSC development began in 2009, and this technology has already achieved 27 % efficiency. Regardless, challenges remain, particularly with the stability of perovskite, which hinders commercialization, e. g., utilizing expensive organic semiconductors. Scientists are working on developing cheaper alternatives which could be synthesized through simpler methods so that to reduce the cost of solar cells. Along with perovskite solar cells, other types of devices have also been developed. The efficiencies of Sb2S3 SC are lower than those of perovskite devices; nevertheless, the stability of the absorbing layer is higher, and no toxic materials are used in the process of its manufacturing. The efficiency of these cells could be increased by using Spiro-OMeTAD or P3HT as HTM. In spite of that, these materials are not highly suitable for Sb2S3 SC due to their high cost, complicated synthesis, and ‘parasitic’ absorption. Based on the experience with perovskite solar cells, it is evident that a properly chosen HTM can enhance the solar cell efficiency. This thesis presents six groups of materials containing fluorenyl and carbazolyl chromophores, exploring their influence on thermal, optical, and photoelectrical properties. Finally, new organic semiconductors were applied to the construction of perovskite and antimony sulfide solar cells, in many cases achieving better stability of the devices. Moreover, utilizing compounds with one fluorenyl chromophore and one or two thiophene moieties in antimony sulfide solar cell led to higher efficiency compared to that of benchmark P3HT
Ca2+ sonotransfer into breast cancer cells in a suspension, 3-D spheroid and subcutaneous tumor models /
No full textCalcium-based treatments have gained considerable attention in the field of electroporation, primarily, due to their comparable efficacy to conventional electro-chemotherapy. However, their applications in sonoporation remain under-investigated, despite its high potential for site-specific and temporally-controlled drug delivery. Current study examines the curative potential of calcium sonoporation across multiple experimental models, including: i) cell suspension, ii) 3-D spheroid culture and iii) subcutaneous murine breast cancer tumors. Murine breast cancer is an established analogue of stage IV human breast cancer. For comparison, parallel experiments, using classical anticancer drug bleomycin were performed. Ca2+ sonoporation efficiently enhanced 4 T1 cell death in a suspension in the absence of microbubbles, under relatively low acoustic pressure (100–200 kPa). In contrast, efficient spheroid growth reduction required microbubble-mediated inertial cavitation at higher (700 kPa) acoustic pressure. In vivo, Ca2+ sonoporation demonstrated similar tumor growth reduction as bleomycin sonoporation. Both treatments reduced tumor growth from the third day after the onset of treatment. Successful cancer treatment was achieved even at lower values of cavitation dose metrics. Our study presents a multi-level validation of Ca2+ sonoporation as an effective treatment strategy for murine breast cancer. Importantly, complete tumor eradication and prolonged animal survival up to one month were observed even at significantly reduced cavitation activity, indicating clinical safety of the treatment
The impact of job resources on sustainable careers of digital nomads.
No full textAs remote work opportunities become more popular around the world, the growth of the digital nomad community is also noticeable. Digital nomads are employees who are using modern technologies daily and can work remotely from anywhere in the world. The significant growth of this phenomenon was stimulated by the COVID-19 pandemic, during which employers and employees were forced to move to a remote work model. It has been noted that employees have recently been looking for more opportunities to work more flexibly and independently. As digital nomad communities expand, difficulties have been observed in the development of employee employer relations. Such a work model requires adaptation, the creation of appropriate working conditions and work flexibility. In this context, a particularly relevant topic is becoming a sustainable career, which speaks of subjectively assessed career nurturing through three main dimensions: happiness, health and productivity. Such a career speaks not only about short-term career satisfaction, but also about a long-term perspective. To understand what affects a nomad's career, it is analysed through work resources, which reflect the following resource categories: social, work environment, organizational and educational. The aim of this study is to understand how job resources affect the sustainable career of digital nomads. It is important not only to discover what impact job resources have, but also to understand the dimensions in which they operate. There are many studies in the scientific literature that analyse individual research studies, but this category of workers is rarely analysed. Project object – The impact of job resources on sustainable careers of digital nomads The goal of the project – To reveal the impact of job resources on sustainable careers of digital nomads To achieve the project goal, the following task were set: to describe the concept and characteristics of digital nomad, discuss the links between job resources and sustainable careers of digital nomads, to develop a methodology for studying the impact of job resources on sustainable careers of digital nomads, and provide recommendations based on a study of the impact of job resources on sustainable career of digital nomads. In this work, when studying the impact of job resources on sustainable career of digital nomads, we turn to the nomads themselves, who describe the impact of individual resources in their daily work environment and relate them to the dimensions of a sustainable career. Analysing how job resources help or interferes them in achieving a sustainable career as they subjectively understand it
Alkali-activated slag repair mortar for old reinforced concrete structures based on ordinary portland cement /
No full textIn this study, alkali-activated mortars were prepared using two different types of fine aggregates: natural sand and biomass bottom ash. These mortars were used as a repair material for structures constructed using old reinforced concrete structures based on Ordinary Portland cement (OPC). Experimental studies have shown that the alkali-activated slag mortar with biomass bottom ash (BBA) from the bubbling fluid bed meets the repair mortar class R1 according to EN 1504-3. The suitability of such repair mortar is determined by the good adhesion properties of the alkali-activated slag binder to old OPC concrete. The adhesion after 28 days was 0.31 MPa and the samples broke off at the repair matrix. The AAC/BBA repair mortar had a compressive strength of 18.69 MPa, the shrinkage due to drying deformations consisted of 0.1903% after 28 days. Alkali-activated slag mortars are effective in repairing, renewing and rebuilding damaged OPC concrete structures
Development of a microbial biofuel cell using biocompatible nanocomposites /
No full textThe expansion and rapid growth of industry has contributed to the generation of large amounts of wastewater. Their treatment is energy-intensive and in some cases uses expensive chemicals. In recent years, researchers have been focusing on new biotechnologies that can harness the organic matter in wastewater to produce energy while at the same time treating the wastewater [1]. In such cases, microbial biofuel cells (MBFCs) are becoming one of the most promising ways to recover energy from wastewater treatment. MBFCs are bioelectrochemical systems that generate an electric current by using micro-organisms, such as the yeast Saccharomyces cerevisiae, which convert chemical energy into electrical energy due to the biochemical redox processes occurring during the metabolism of the micro-organisms [2]. Despite numerous experiments, most microbial biofuel cells have one important and common drawback: low current density due to the complexity of the charge (e.g. electron) transfer between the micro-organism cells and the electrodes. By facilitating the transfer of charge from the micro-organisms to the electrode, the overall efficiency of MBFC can be significantly improved. One of the main obstacles to low charge transfer efficiency is the high electrical resistance of the micro-organism cell walls [3]. [...]
Derivatives of 2,7-dibromo-9,9-dimethyl-9h-fluorene and 2,7-dibromo-9,9-spirobifluorene as electroactive materials /
No full textLow-molar-mass and polymer organic light emitting diodes have attracted considerable attention due to their great application potential in large area flat panel displays and solid state lighting [1 ]. Such devices tend to have multilayer device configuration with a hole transport layer, an electron transport layer and an emissive layer, and some of them also have a hole injection and an electron injection layer [2]. The selection of appropriate materials for each layer is of great importance. Generally, the molecular structures of hole transport materials usually contain electron-donating moieties, such as carbazole, triarylamine, diphenylamine, N-phenyl-1-naphthylamine etc. [3]. However, traditional methods for synthesizing electroactive materials have notable drawbacks such as low reaction yields, longer reaction times, dependence on hazardous, expensive and moisture-sensitive reagents, as well as involving large amounts of reactants. Additionaly, these methods often require intense reaction conditions, longer workup procedures, and difficulties in catalyst regeneration. In this work, we employed efficient Suzuki coupling reactions of 2,7-dibromo-9,9-dimethyl-9H-fluorene and 2,7-dibromo-9,9’-spirobifluorene with (B-(9-phenyl-9H-carbazol-3-yl)-boronic acid and (6-Phenyldibenzo[b,d]furan-4-yl)boronic acid. Their thermal, electrochemical, and photophysical properties will be presented
Research on the application of blockchain technology in accounting and auditing.
No full textThis thesis analyses the application of blockchain technology in the accounting and auditing sectors using the Technology–Organization–Environment (TOE) theoretical framework. In the context of digital transformation, blockchain is becoming one of the most significant innovations capable of fundamentally changing data management, security, and transparency principles. It is particularly relevant in the fields of accounting and auditing, where information reliability and control are essential. As the demand for data integrity and technological solutions increases, this topic gains importance in ensuring operational efficiency and compliance. However, the practical implementation of blockchain in organizations still faces various challenges, which highlights the need to examine the factors influencing its integration. The object of the research is the factors influencing the application of blockchain technology in accounting and auditing. The aim of the research is to investigate which factors affect the implementation of blockchain technology in these fields. The theoretical part of the thesis reviews scientific literature on blockchain adoption and the influencing factors. The empirical part presents quantitative research findings based on a survey of representatives from Lithuanian accounting and auditing service companies. The data were analysed using correlation, regression, and multivariate analysis of variance (MANOVA) methods. The research results revealed that organizational factors – particularly managerial support, employee competence, and readiness for change – have the most significant influence on the decision to adopt blockchain technology. Technological and environmental factors (e.g., infrastructure, system compatibility, government support) were found to be more relevant in the later stages of implementation. Sociodemographic factors such as gender, age, or position were not statistically significant; however, company size and employee work experience were positively associated with the likelihood of adopting the technology. The study is limited by its geographic scope (Lithuania) and the subjective nature of survey responses. Nonetheless, the results provide valuable insights into the practical opportunities and challenges of applying blockchain in accounting and auditing, contributing to further empirical research in this field
The impact of visual appeal of human and AI-generated content on consumer response.
No full textThe rapid advancement of artificial intelligence is fundamentally reshaping marketing practices—from the processes of visual content creation to the ways in which consumers perceive and respond to brand communications. Recent studies indicate that while AI-generated content can be aesthetically appealing and economically efficient, consumers may react sensitively to the disclosure of authorship and to issues related to authenticity (Gao & Liu, 2022; Brüns & Meissner, 2024). This study examines the impact of human – versus AI-generated advertising visuals on consumer response, with particular attention to content appeal, perceived authenticity, and the moderating role of technology resistance. The research is motivated by contradictory findings in prior studies (Hartmann, Exner & Domdey, 2024; Elhajjar, 2024) and the growing need to better understand under what conditions AI-created content is accepted by consumers and when it triggers skepticism. The theoretical framework of this study is based on three interrelated perspectives: the processing fluency theory (Schwarz et al., 2020), which explains how easily processed content elicits positive emotional reactions; the aesthetic perception theory (Shi et al., 2021), which highlights the importance of design elements – such as color, proportion, and harmony – for consumers’ aesthetic satisfaction; and the authenticity theory (Ren et al., 2023), which interprets perceived genuineness and sincerity in content as essential drivers of consumer trust and behavioral intentions. In this study, visual appeal was operationalized through two components – processing fluency and aesthetic perception and their effects on consumer behavior were assessed through the mediating role of perceived authenticity. The latter was considered a central mechanism influencing consumer intentions, such as willingness to share, like, or recommend the content. Additionally, technology resistance was included as a moderating variable, potentially strengthening or weakening consumers’ responses to AI-authored advertising. An experimental design was applied between subjects manipulating content authorship (human vs. AI) and level of technology resistance (high vs. low). The results revealed that human authorship significantly increased both perceived processing fluency and aesthetic appeal, particularly among participants with high levels of technology aversion. Visual appeal predicted higher perceived authenticity, which in turn predicted stronger behavioral intentions. However, aesthetic perception exerted a weaker influence on authenticity than processing fluency. Based on these findings, it is recommended that brands explicitly communicate the human creative contribution in AI-generated content, especially when targeting audiences with higher skepticism toward technology. Furthermore, a hybrid creative strategy—combining the efficiency of AI with the authenticity of human input—is advised to foster long-term consumer trust and engagement