Research Articles

This study aimed to evaluate the phytochemical composition, antimicrobial properties, mosquito larvicidal effects, and brine shrimp toxicity of essential oils obtained using hydrodistillation from the fresh and dried leaves of Eucalyptus grandis × Eucalyptus urophylla at two age groups. Leaves from trees aged 17 to 31 months old yielded more essential oils than those aged 40 to 50 months. Gas chromatography-mass spectrometric analysis revealed that 1,8-cineol (13.1% to 26.7%) and α-terpinyl acetate (18.3% to 26.1%) were the dominant components across all essential oils. All tested essential oils inhibited Gram-positive bacteria, yeasts, and the dermatophyte Trichophyton rubrum, but failed to exhibit activity against most of the tested Gram-negative bacteria and Aspergillus fumigatus. The minimum inhibitory concentrations ranged from 0.16 to 2.50 mg/mL for bacteria and 0.04 to 1.25 mg/mL for fungi, highlighting the greater antifungal efficacy of the essential oils. All tested essential oil samples were also active against third instar larvae of Aedes aegypti and Aedes albopictus, with median lethal concentrations of 52.3 to 134 µg/mL after 24 h, lower than that of against Artemia franciscana nauplii (209 and 222 µg/mL). Therefore, Eucalyptus grandis × Eucalyptus urophylla essential oils are potential larvicidal agents for mosquito control with low toxicity to aquatic organisms.

The wood and furniture sector faces challenges in adopting digital and sustainability practices, mainly due to a lack of competencies for effective implementation. While current educational reforms in Slovenia emphasize the development of digital and sustainability competencies at all levels of wood science and technology education, the role of motivation, one of the key drivers of learning, in shaping these competencies has not been sufficiently explored. This study investigated how academic motivation affects students, self-perceived digital and sustainability competencies. A survey was conducted among 433 final-year students in wood science and technology education programs, including secondary vocational and technical, short-cycle higher vocational, and higher education institutions. The Academic Motivation Scale was used along with instruments derived from established European digital and sustainability competence frameworks. Structural equation modeling revealed that students’ academic motivation positively predicted their self-perceived generic digital, generic sustainability, and professional digital and sustainability competencies, and explained between 22 and 29% of the variance. Intrinsic and extrinsic motivation were not shown to be distinct dimensions, but formed a unidimensional construct, suggesting that both internal interests and external incentives jointly support the perception of these competencies. Students’ academic motivation is a decisive factor for their self-perceived digital and sustainability competencies in wood science and technology education.

Efficient production of cellulose nanofibers (CNFs) from wood pulp remains a challenge for industrial applications, requiring optimized pretreatment and processing strategies. In this study, hardwood kraft pulp (Hw-BKP) was pretreated with NaOH solutions (5 to 20 wt%) and subsequently processed using a large-scale wet grinder. The effects of pretreatment concentration and grinding on nanofibrillation efficiency were evaluated through compositional, structural, and optical analyses. Alkali pretreatment promoted hemicellulose removal and crystalline transforma-tion, while mechanical grinding facilitated progressive microfibrillation. Notably, pretreatment at concentrations above 15 wt% significantly enhanced nanofibrillation efficiency, highlighting the importance of crystalline transformation in addition to hemicellulose removal. These findings provide practical insights for optimizing CNF production processes and advancing their industrial-scale commercialization.