Development of hybrid TiO2/SWCNT photocatalysts

Tese de mestrado integrado. Engenharia Química. Faculdade de Engenharia. Universidade do Porto. 200

Response of the Diatom Phaeodactylum tricornutum to Photooxidative Stress Resulting from High Light Exposure

The response of microalgae to photooxidative stress resulting from high light exposure is a well-studied phenomenon. However, direct analyses of photosystem II (PSII) D1 protein (the main target of photoinhibition) in diatoms are scarce. In this study, the response of the diatom model species Phaeodactylum tricornutum to short-term exposure to high light was examined and the levels of D1 protein determined immunochemically. Low light (LL) acclimated cells (40 µmol photons m−2 s−1) subjected to high light (HL, 1,250 µmol photons m−2 s−1) showed rapid induction of non-photochemical quenching (NPQ) and ca. 20-fold increase in diatoxanthin (DT) concentration. This resulted from the conversion of diadinoxanthin (DD) to DT through the activation of the DD-cycle. D1 protein levels under LL decreased about 30% after 1 h of the addition of lincomycin (LINC), a chloroplast protein synthesis inhibitor, showing significant D1 degradation and repair under low irradiance. Exposure to HL lead to a 3.2-fold increase in D1 degradation rate, whereas average D1 repair rate was 1.3-x higher under HL than LL, leading to decreased levels of D1 protein under HL. There were significant effects of both HL and LINC on P. tricornutum maximum quantum yield of PSII (Fv/Fm), showing a reduction of active PSII reaction centres. Partial recovery of Fv/Fm in the dark demonstrates the photosynthetic resilience of this diatom to changes in the light regime. P. tricornutum showed high allocation of total protein to D1 and an active D1-repair cycle to limit photoinhibition

Momentary emotional states in primary school children: combined effects of chronotype X time-of-day

Synchrony effects regarding mood diurnal fluctuations (i.e., better mood at optimal and worse mood at suboptimal times-of-day, corresponding to the interaction between chronotype* time-of-day) have been studied in adolescents and adults. However, evidence in children is lacking. We investigated the interactive effect of chronotype and time-of-day on primary school children’s momentary emotional states, in a naturalistic setting. From an initial pool of 298 3rd/4th graders (7–11 years-old), 134 Morning (M)-type and Evening (E)-type children were selected using the parental-report Children ChronoType Questionnaire (CCTQ). Potential covariates were assessed based on parental questionnaires. Students completed emotional states’ measures on the first (9 a.m.) and last lessons (4 p.m.) of the school day, in a counterbalanced order. Given the intercorrelations between emotional measures, a composite score of momentary emotional states was determined. There was a small-to-moderate significant interactive effect of chronotype*time-of-day in the overall momentary emotional states score. M/E-types showed better overall momentary emotional states when tested at their optimal time-of-day. Chronotype or time-of-day main effects were non-significant, and the overall momentary emotional states score did not correlate with sleep or psychopathological symptoms. In the present study, children overall momentary emotional states in a naturalistic setting varied depending on chronotype combined with time-of-day.This work was supported by the European Regional Development Fund / Fundo Europeu de Desenvolvimento Regional (FEDER), through the Portugal-2020 (PT2020) and the Central Regional Operational Programmes / Programa Operacional Regional do Centro (Centro 2020), and by the Portuguese Foundation for Science and Technology / Fundação para a Ciência e Tecnologia (FCT) - I.P./ MCTES through national funds (PIDDAC). Project grant references: PTDC/PSI-ESP/32581/2017. CENTRO-01-0145-FEDER-032581

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved