16168 research outputs found
Sort by
Development of thyme essential oil-based coatings and assessment of their antimicrobial activity /
No full textIn this study, coatings composed of acrylic binder, starch sodium octenylsuccinate and essential oil (EO), as a volatile antibacterial agent were developed and applied to polypropylene films. Among various EOs tested, thymol exhibited the highest antimicrobial activity in agar diffusion assays, resulting in inhibition zone of 12.3 ± 1.2 to 40.0 ± 1.0 mm with Escherichia coli and 11.3 ± 0.6 to 88.0 ± 1.0 mm with L. monocytogenes. Based on these results, thymol was selected and incorporated in the coatings, and the antimicrobial activity of films with coatings containing various amounts of thyme EO (585 ± 30 – 2159 ± 112 µg/cm2) were assessed using both agar diffusion and vapor diffusion assays. Films with the highest amount of thyme essential oil (2159 ± 112 µg/cm2) exhibited significant antimicrobial activity in the agar diffusion test. In vapor diffusion assays the active films demonstrated a significant antibacterial effect, producing a log reduction of 2.3 log E. coli and 3.8 for L. monocytogenes. Studies on the release of thymol, the main antibacterial component of thyme EO, revealed a continuously release with a maximum concentration of 21.85±2.11 µg/cm3 achieved after 10 days. The results further indicated that only a very small proportion of the thymol in the coating was released during the storage period
Experimental investigation of suspended water, ethanol and acetone droplets transient phase change regimes in the heated airflow /
No full textThis paper presents an experimental investigation into the use of water, ethanol, and acetone using the suspended droplet method. The influence of atmospheric air temperatures on droplets in the transient phase change is analysed. Experimental results are presented, including ther mograms that characterise the droplet's thermal state and diameter monograms that define the variation in droplet size. These data are processed according to the droplet liquid volume change rate parameter. The experimental results confirm that the airflow temperature leads to intensified heat exchange and phase change processes during the droplet transition stages, resulting in the droplet's heating to a higher thermal equilibrium evaporation state. For all the fluids studied, the impact of airflow temperature on the droplet temperature and liquid volume change rate of different liquids is qualitatively similar. Still, the strength of the influence varies depending on the nature and properties of the liquid. In heated air up to 50°C, the droplet equilibrium temperatures are approximately 8.5°C for acetone, 22.2°C for ethanol and 28.3°C for water. In 100°C air, these values become approximately 17.8°C, 32.3°C and 43.4°C, respectively. The estimated volume change in the liquid droplet's size and vapour mass flux show that acetone, which has the most volatile properties and lowest boiling temperature, evaporates most intensely from the liquids tested in the initial stage
Recent synthetic advances in C–H/N–H functionalization of 1H-pyrazoles: diverse strategies across variously substituted scaffolds /
No full textThis review briefly and systematically overviews C–H and N–H functionalization reactions of pyrazoles, aimed at creating new CC and Cheteroatom bonds on the pyrazole ring. It discusses various strategies, including traditional cross-coupling reactions that necessitate prefunctionalized pyrazoles as well as direct functionalization reactions, which offer a more efficient approach to obtaining a diverse array of functionalized derivatives in only one step
Physical properties comparison of two-dimensional materials: MXene and graphene oxide /
No full textTwo-dimensional (2D) nanomaterials are promising for many different applications. Therefore, detailed characterization and knowledge of their properties are needed. This work focused on graphene oxide (GO) and a new 2D nanomaterial, MXene, type Ti3C2Tx. The spray coating method was used to create thin GO and MXene films on a glass substrate. Their composition was characterized by X-ray photoelectron spectroscopy. Scanning probe microscopy (SPM) imaging and surface free energy calculation confirmed the homogenous coating of the substrate. The mechanical properties of the prepared films were measured by nanoindentation. The elastic modulus was independent of the film thickness; it was approximately 89 GPa for the MXene samples and approximately 100 GPa for the GO samples. Lower hardness values were determined for thicker films: 10.5 GPa for 5-layer MXene vs. 7.5 GPa for 10-layer MXene and 13.0 GPa for 5-layer GO vs. 9.8 GPa for 10-layer GO. Contact angle measurements and surface energy calculations were performed for all prepared films with 5 or 10 layers. MXenes oxidize on air over time, and the highly conductive Ti3C2Tx structure changes to less conductive titanium oxides. The aging of MXene was studied by monitoring the MXene film conductivity within two months, which showed a decrease, but the 10-layer films were more stable than the thinner 5-layer films
Energy literacy and energy poverty in Austria, Bulgaria, Greece, Italy and Lithuania: insights from the e-lit adults project :
No full textFor millions of Europeans, access to energy is not only a matter of comfort, but also of security and dignity. In 2022, over 41 million EU citizens were unable to keep their homes adequately warm, while an even larger number expressed concern about unpaid utility bills (Eurostat, 2023). These statistics reflect the lived realities of families forced to choose between heating and food, older adults reluctant to use heating out of fear of unaffordable costs, and parents striving to maintain a safe environment for their children. The Erasmus+ project Energy Literacy for Adults (E-lit Adults) undertook a comprehensive study in five partner countries–Austria, Bulgaria, Greece, Italy, and Lithuania– to gain a clearer picture of the situation across Europe. The consolidated report presents a comparative analysis of energy-related knowledge, attitudes, and behaviors, based on survey data from nearly 700 adults at risk of energy poverty and a review of relevant documents (E-lit Adults, 2024)
Arnold tongues of divergence in the Caputo fractional standard map of nilpotent matrices /
No full textArnold tongues of divergence in the Caputo fractional standard map of nilpotent matrices are explored in this paper. The scalar iterative variables in the Caputo fractional standard map are replaced by iterative matrix variables. The divergence effects induced by the nilpotent matrices result in specific patterns of Arnold tongues. Automatic machine classification techniques help to identify different types of Arnold tongues according to the dynamics of the transient processes of the system. Computational experiments are used to validate theoretical insights and to reveal the patterns of Arnold tongues of divergence
Morphological, compositional and optical properties of CuxS films on FTO glass /
No full textIn this study, by varying the concentrations of the precursors used, copper sulfide films were deposited on FTO glass using the sequential ionic layer adsorption and reaction (SILAR) method and the following copper sulfide phases were detected: anilite, djurleite, chalcocite, and yarrowite. It was found that the films of copper sulfides are unevenly distributed, that the crystallinity of the films increases with increasing annealing temperature from 100 to 400 °C, and that the particles aggregate into agglomerates. The films formed were found to be dominated by copper sulfides, and the calculated molar ratio of copper to sulfur varied with the concentrations of the precursors used, ranging from 1.4 to 2.2. The values of the band gap energy were not significantly affected by the change in the concentrations of the precursors and the annealing temperature, varying between 1.0 and 1.5 and 1.95–2.15 eV
Nanosecond laser-fabricated titanium meshes and their chemical modification for photocatalytic and SERS applications /
No full textThis study presents the fabrication and chemical modification of titanium meshes produced by nanosecond laser drilling, tailored for advanced photocatalytic and surface-enhanced Raman scattering (SERS) applications. Titanium meshes were fabricated via pulsed laser ablation (TM_1) and subsequently modified either by deposition of silver nanoparticles through irradiation (TM_2) and sonication (TM_3) or by surface oxidation using hydrogen peroxide (TM_4). Morphological and compositional analyses revealed that these modifications lead to distinct Ag nanoparticle morphologies and significant increases in surface oxygen content, notably enhancing photocatalytic performance. Photocatalytic tests demonstrated that the TM_4 mesh achieved the highest degradation rate of methylene blue, underscoring the critical role of surface oxygen enrichment. In contrast, TM_2 and TM_3 exhibit strong potential as surface-enhanced Raman scattering (SERS) substrates due to the well-distributed plasmonic silver nanostructures that enhance local electromagnetic fields. Their three-dimensional porous architecture facilitates high surface area and efficient analyte adsorption (MB), further improving SERS sensitivity. These findings establish nanosecond laser-processed titanium meshes, particularly those that are chemically modified, as promising, scalable materials for efficient water purification and effective SERS substrates for molecular sensing
Advances in food-grade hydrogel encapsulation of probiotics with next-generation prebiotics for targeted synbiotic delivery /
No full textBackground. Hydrogel-based encapsulation represents a successful method for preserving probiotics and their functionality during processing, storage, and gastrointestinal transit. Although conventional systems offer protection, advances in next-generation prebiotics such as polyphenols and non-digestible carbohydrates have shifted the focus toward multifunctional synbiotic delivery systems. These materials provide sustainable, food-grade design and improve both structural integrity and bioactivity. Additionally, fabrication and crosslinking methods such as ionic interactions, Maillard conjugation, and enzymatic or pH-responsive techniques facilitate precise hydrogel customization for targeted probiotic release. Scope and approach. This review discusses recent progress in natural and composite hydrogels for probiotic encapsulation, with particular attention to the influence of next generation prebiotics on hydrogel functionality. A decision-oriented design framework is presented, aligning target sites and release triggers with materials and crosslinking strategies, exemplified with quantitative results. This framework offers a systematic approach for selecting food-grade matrices and encapsulation methods. Key findings and conclusions. Natural and composite hydrogels provide effective protection against oxygen, heat, acidity, bile salts, and digestive enzymes, maintaining a hydrated and biocompatible microenvironment. Protein–polysaccharide combinations increase mechanical and rheological stability, while next-generation prebiotics further reinforce structural integrity and bioactivity. Encapsulation efficiencies above 90 percent and enhanced cell viability in simulated digestion demonstrate promising performance of these systems. The integration of quantitative mapping and design principles establishes a practical framework for developing scalable, food-grade, multifunctional synbiotic hydrogels, supporting advancements in probiotic delivery technology. Adopting standardized digestion models and prioritizing in vivo validation will aid the development of synbiotic hydrogels acceptable in real food systems
The Nobel “Pride” phenomenon: an analysis of Nobel prize discoveries and their recognition /
No full textThe Nobel Prize is considered one of the highest forms of recognition of scientific accomplishment, conferring immense prestige upon its recipients. Given the significant time lag between the award and the discovery, Nobel Prizes are bestowed to individuals associated with institutions and countries other than the original place of the discovery. Contextualizing our research in status-seeking literature, we define the imprecise and sometimes excessive appropriation of Nobel Prizes by institutions and even countries as the “Nobel ‘Pride’ Phenomenon”. Our empirical analysis focuses on the time and location of the 653 discoveries underlying each of the 350 Nobel Prizes in medicine, physics, and chemistry until 2024. About one-third of all Nobel laureates came from another institution or country. Furthermore, Nobel Prize creativity is highly concentrated, with more than 80 % of discoveries made in just five countries. These findings cast new light on the Nobel laureates’ demographics, geographic and historical movements, and institutional affiliations, and have implications for research policy at institutions and national levels