Institute of Chemistry

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    Semi-Quantitative Characterization of Volatile Organic Compounds in Indoor and Outdoor Air Using Passive Samplers: A Case Study of Milan, Italy
    (MDPI AG, 2025-09-16)
    Mula, Vllaznim
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    Zeneli, Lulzim
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    Mehmeti, Valbonë
    This study presents a semi-quantitative characterization of volatile organic compound (VOC) concentrations and their emission sources in indoor and outdoor environments across four residential and laboratory sites in Milan, Italy, during the summer of 2024. Radiello® passive samplers (Fondazione Salvatore Maugeri in Padova, Italy) were employed for VOC collection, followed by gas chromatography–mass spectrometry analysis. The semi-quantitative mean total VOC (TVOC) concentration was 220.8 ± 195.4 µg/m3 for the outdoor air and slightly higher at 243.6 ± 134.3 µg/m3 for the indoor air, resulting in an indoor-to-outdoor relative ratio of 1.10. The outdoor VOC profile was dominated by hydrocarbons, accounting for 80.3% ± 4.6% (173.2 ± 143.8 µg/m3) of TVOCs, followed by aromatic hydrocarbons at 13.3% ± 5.5% (37.2 ± 49.7 µg/m3). Indoors, hydrocarbons also predominated, representing 34.1% ± 15.2% (95.2 ± 80.1 µg/m3) of the TVOCs, followed by terpenes at 20.7% ± 15.5% (49.0 ± 46.4 µg/m3). Other VOC groups contributed smaller fractions in both environments. The emission profiles from cleaning and personal care products were assessed semi-quantitatively to determine their relative percentage contributions to the indoor VOCs. Source attribution was further supported by diagnostic relative ratios—benzene/toluene, toluene/benzene, and (m + p)-xylene/ethylbenzene—which provided insight into dominant emission sources and photochemical aging.
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    Innovative Learning Activities for Ethnically Diverse Students in Macedonian Science Education
    (University of Ljubljana, 2024-03-29)
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    Petruševski, Vladimir
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    Naumoska, Aleksandra
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    Tofilovska, Slavica
    <jats:p>A game-based approach is widely used to increase students’ motivation through their active participation, whereby research is interwoven with fun and competition is incorporated with cooperation. Working in teams or groups encourages students to exchange their opinions, to try to find solutions together or to win a game. In this way, they learn and improve skills such as collaboration and responsibility. Several activities involving the 5E model as part of inquiry-based science education and an escaperoom as part of game-based learning were used in science classes (chemistry, biology and physics). The activities were designed on three different topics – gases, ecology and electrical circuits – within the project “Diversity in Science towards Social Inclusion – Non-formal Education in Science for Students’ Diversity”. The activities focused on the students’ self-concept towards science, interest in the subject, motivation and careeraspirations in STEM, as well as the effectiveness of the implemented activities. The study aimed to assess the potential advantages of implementing activities in an ethnically diverse environment, benefiting both students and teachers. Pre- and post-questionnaires were designed and distributed to 190 students from various primary and secondary schools in Macedonia. The present paper provides an overview of game-based activities as well as a brief analysis of the pre- and post-questionnaire responses fromstudents, focusing on the topic of ecology.</jats:p>
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    Exploiting the Electrical Nature of Biofilms for Long-Term Monitoring of Quiescent Aquatic Environments via Open-Circuit Microbial Potentiometric Sensors: Evidence of Long-Distance Electrical Signaling
    (Nano LIFE, 2023)
    Burge, Scott R.; Hristovski, Kiril D.; Burge, Russell G.; Pejov, Ljupco; Boscovic, Dragan; Taylor, Evan; Hoffman, David A.
    This study was based on the hypothesis that spatial–temporal characterization of contaminant- affected redox gradients in a quiescent system could be measured by microbial potentiometric sensor (MPS) arrays incorporated in large, natural biofilm networks. Two experimental chambers, each containing at least 48 equidistantly located MPS electrodes, were fabricated to examine reproducibility of the patterns. The MPS electrodes were exposed to biofilm growth conditions by introducing high dissolved organic carbon (DOC) and dechlorinated tap water at the bottom of the experimental chamber; and the spatial–temporal changes in the MPS array signals were recorded, which showed that signal trends were correlated to the induced changes in DOC. The results indicated that MPS arrays measured the spatial–temporal changes in the aqueous solution caused by an influx of carbon rich water, which could not be detected by conventional oxidation-reduction potential (ORP) electrodes. Interestingly, the experiments conducted over long time periods revealed unusual behaviors like electrical signaling and possible potentiometrically driven communication within the biofilm. These observed behaviors suggest that biofilms may create a large network through which communication signals can be generated and propagated by inducing changes in electric potentials similar to a sophisticated electronic device.