A soluble, green-blue fluorescent, pi-extended azatrioxa[8]circulene was synthesized by oxidative condensation of a 3,6-dihydroxycarbazole and 1,4-anthraquinone by using benzofuran scaffolding. This is the first circulene to incorporate anthracene within its carbon framework. Solvent-dependent fluorescence and bright green electroluminescence accompanied by excimer emission are the key optical properties of this material. The presence of sliding pi-stacked columns in the single crystal of dianthracenylazatrioxa[8]circulene is found to cause a very high electron-hopping rate, thus making this material a promising n-type organic semiconductor with an electron mobility predicted to be around 2.26 cm(2) V-1 s(-1). The best organic light-emitting diode (OLED) device based on the dianthracenylazatrioxa[8]circulene fluorescent emitter has a brightness of around 16 000 Cd m(-2) and an external quantum efficiency of 3.3 %. Quantum dot-based OLEDs were fabricated by using dianthracenylazatrioxa[8]circulene as a host matrix material.

Contamination by hazardous substances is one of the main environmental problems in the eastern Gulf of Finland, Baltic Sea. A trilateral effort to sample and analyse heavy metals (HMs), polycyclic aromatic hydrocarbons (PAHs), and organotins from bottom sediments in 2019–2020 were conducted along with harvesting historical data in Russian, Estonian and Finnish waters. We suggest that the input of organotins still occurs along the ship traffic routes. The tributyltin content exceeded the established quality criteria up to more than 300 times. High contamination by PAHs found near the ports, most likely originate from incomplete fuel incineration processes. The Neva River Estuary and Luga Bay might potentially suffer from severe cadmium contamination. The high ecological risk attributed to the HMs was detected at deep offshore areas. The simulated accumulation pattern qualitatively agrees with field observations of HMs in sediments, demonstrating the potential of numerical tools to tackle the hazardous substances problems.

Työn tavoitteena oli selvittää polttoöljyn suorapolton soveltuvuutta viljankuivaukseen tarkastelemalla kansallista lainsäädäntöä, paloturvallisuusmääräyksiä, elintarvikevaatimuksia, sekä polttotekniikkaa ja palamistulosta. Lisäksi toteutettiin käytännön kuivauskoe tekniikan toimivuuden, sekä mahdollisten haitallisten viljan kontaminaatioiden selvittämiseksi. Suorapolttoinen uuni on rakenteeltaan yksinkertaisempi ja hyötysuhteeltaan lämmönvaihtimella varustettua uunia parempi. Suorapolttoisia uuneja on käytössä viljankuivauksessa Suomessa jo maa- ja nestekaasukäyttöisinä. Lisäksi muualla Euroopassa käytetään suorapolttoisia öljyuuneja. Kirjallisuuden perusteella suorapoltto saattaa kohottaa kuivattavan viljan PAH- ja raskasmetallipitoisuuksia, jos poltin on säädetty ali-ilmalle. Suomen lainsäädännöstä ei löytynyt estettä öljyn suorapolton käytölle. Kuivauskokeessa todettiin tekniikan toimivan hyvin. Koe toteutettiin sekä polttimen optimisäädöillä, että ali-ilmalle säädetyllä polttimella. Vertailuksi otettiin näytteet myös lämmönvaihdinta käyttäen kuivatusta erästä. Viljanäytteistä analysoitiin PAH4-, lyijy- ja kadmiumpitoisuudet. Näytteistä ei havaittu haitallisia määriä edellä mainittuja yhdisteitä. Tutkimuksessa ei löytynyt suorapolton käyttöä estäviä tekijöitä. Tutkimuksen perusteella suorapolttoa voidaan pitää yhtenä vaihtoehtona viljankuivauksen lämmönlähdettä valittaessa myös Suomessa.

Polycyclic aromatic hydrocarbon (PAH) contamination in food poses a potential risk to human health. PAHs are formed primarily as a result of incomplete combustion of organic material and can enter the food chain either from the environment or from food manufacturing processes such as smoking, roasting, drying and grilling. As some of them are known to cause cancer, it is important to reduce the PAH levels in foods as low as is reasonably achievable. The European Food Safety Authority (EFSA) has evaluated the sum of PAH4 compounds (=benzo[a]pyrene (BaP), benz[a]anthracene (BaA), chrysene (CHR) and benzo[b] fuoranthene (BbF)) to serve as a suitable indicator of both the occurrence and toxicity of the PAHs. The primary purpose of this dissertation study was to assess for the frst time Finnish children’s potential health risk caused by dietary exposure to PAH4. In order to complete this task, the applied analytical method must be appropriately validated to be able to produce precise occurrence data. In this study, the gas chromatography-tandem mass spectrometry method was successfully validated according to legislative requirements and the occurrence of PAH4 in a wide range of food groups (fsh, meat, fat and oil, bread, cereal and muesli) was determined. Generally, the concentrations of PAH4 in foods were low and below the prevailing maximum levels. That being said, in smoked fsh and meat products, the variation of the detected PAH4 levels was high, up to 200 µg/kg in smoked ham. It appeared that the smoking process was either controlled or not, and the science-based guidance is required to prevent and reduce contamination of PAHs. Therefore, our goal was to investigate the critical smoking factors that afect the PAH4 formation in fsh and meat products in order to provide tools for manufacturers to produce safer smoked products, thereby decreasing human dietary exposure and adverse health efects. Based on our results, indirect smoking, smoking in less than fve hours, optimised smoke generation temperature between 400 and 600 °C and distance more than fve metres between the food and the smoke source led to reduced PAH4 levels in smoked fsh and meat products. This study aimed to gain a better understanding of the potential mutagenicity of the processed foods, and therefore selected fsh and meat products were tested by the Ames test in Salmonella TA 100 and TA 98 strains with or without metabolic activation. The outcome was further compared to the chemical PAH4 analyses. The statistically signifcant mutagenic response was observed in all three lots of smoked Baltic herring, which also indicated higher PAH4 concentrations than other samples. By contrast, the tested meat products were not mutagenic and the corresponding individual PAH4 concentrations were, for the most part, undetectable. Despite the challenges in food mutagenicity testing, our results provided more information on the potential mutagenic activity of various foods. Specifcally, based on our fndings, a combination of both biological assays and chemical analyses can improve the interpretation of the fndings regarding mutagenicity. Lastly, in reference to our primary purpose of considering potential safety concerns of PAH4 in food, Finnish children’s dietary exposure to PAH4 was evaluated by combining the acquired occurrence and food consumption data. Utilising that data, a margin of exposure (MOE) was calculated in order to be used to provide relative indication of the level of health concern and support prioritisation of possible risk management actions. Our results demonstrated that bread, smoked ham, fat and oil and sausage contributed the most to BaP and PAH4 exposure. Even though the mean PAH4 levels in bread were below the limit of detection, its consumption volumes are high, which explains the contribution. Children’s total mean dietary exposure was estimated to BaP 1,500 pg/kg bw/day and to PAH4 8,100 pg/kg bw/day. The total margins of exposure (MOEs) for children were 482,000 for BaP and 42,000 for PAH4. Furthermore, the calculated MOEs for highly exposed children were also above the reference value 10,000, which caused them to be considered of low concern. Taking into account uncertainties and limitations, this study indicated no health risk to Finnish children aged three to six years.