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The paper reports a study aimed at investigating tertiary education students' engagement and interactions in the traditional face-to-face learning environment and the sequentially applied distance online learning environment imposed by the sudden upsurge of a worldwide health emergency, the COVID-19 pandemic in Spring 2020. The study took place in four distinct science learning communities formed by a total of 347 undergraduate students attending three different academic majors (Chemistry, Environmental Science, and Food Science and Technology) and 13 postgraduate students attending a Masters program related to Chemistry Education, in two Greek universities. The majority of the measured variables were shown to depend on the institution, the academic major, and the semester of study, although to a varying degree. Data analysis provided evidence for a statistically significant lower level of emotional engagement in the online relative to the traditional learning environment among the students of all three undergraduate learning communities. Multiple regression analysis showed that this documented decrease in students' emotional engagement is largely explained by the concurrent decrease at the level of human interaction (either student-student or student-instructor) upon the passage from the traditional to the online learning environment.

This study aims at investigating students' awareness of green chemistry principles (GCPs) which are infused in two context-based projects that are related to socio-scientific issues, namely climate change and materials' recycling. At first, content analysis of the projects' activities showed the infusion of four GCPs. Subsequently, the students' written reports associated with these activities were evaluated in order to examine the incorporation of different GCPs in their argumentation. The four principles identified in the first part of the study, were also shown to be incorporated in students' argumentation, although with variable frequency. The specific themes which manifest students' awareness of the different GCPs were also identified. These themes may guide the effective design of educational material dedicated to the infusion of GCPs in chemistry education, thus contributing to the promotion of students' environmental awareness and the development of skills which characterise socially responsible citizenship.

This study aimed at investigating the issue of domain specificity of motivation across specific science disciplines (chemistry and physics) in combination with influencing factors related with students' academic major and gender. A clustered sampling was used to select 281 participants who were undergraduate students (105 males and 176 females) attending three different academic majors (Environmental Technology, Conservation of Cultural Heritage, Food Technology) at a Greek tertiary education institution. Motivation to learn chemistry and physics was evaluated concurrently using the discipline-specific (Chemistry and Physics) versions of Science Motivation Questionnaire II (SMQ II) denoted as CMQ II and PMQ II, respectively. Discipline-based comparisons showed the existence of domain specificity in motivation with the whole student sample displaying higher motivation to learn chemistry relative to physics in all five motivational scales of SMQ II (self-efficacy, self-determination, intrinsic motivation, career motivation and grade motivation). Multivariate analysis of variance (MANOVA) and discriminant function analysis showed that students' motivation to learn chemistry and physics depends strongly on their academic major. Furthermore, MANOVA provided evidence for a small gender effect on motivation for either chemistry or physics learning. The implications of the current study for effective tailor-made educational practice and research across different science disciplines are critically discussed.

Green chemistry refers to the design and application of practices that prevent pollution and promote environmental sustainability. A set of 12 principles make up the core of the green chemistry philosophy, and, since their emergence, they have been implemented in the educational practice of tertiary education. Over the past few years, the green chemistry approach has started expanding among secondary education as well. This review discusses green chemistry teaching experiences in secondary education as reported in 70 scientific publications (from 2002 to the present) that were identified via a literature search. All identified documents were examined and analyzed to map their green chemistry content and relevant environmental issues, the degree of the connection between the chemistry concepts and environmental issues ("environmentalization"), the implemented teaching-learning approaches, and, when applicable, the achieved learning outcomes. Analysis showed that all 12 green chemistry principles were covered within the identified publications, with the ones referring to prevention and the use of renewable feedstocks being the most frequent. The publications touch upon several environmental issues, with the most frequent being those referring to hazardous chemical waste, alternative energy resources, and recycling. Most of the publications correspond to a medium degree of environmentalization. The inquiry-based, hands-on-based, problem-based, context-based, and socio-scientific issues-based teaching approaches were shown to be the most widely used. Regarding the achieved learning goals, those mostly explored were related to the cognitive and affective domains. This comprehensive review may provide a solid foundation for the organization and design of novel curricula that will integrate green chemistry into education for sustainable development programs in secondary education. [ABSTRACT FROM AUTHOR]

In the summer of 2021, Greece experienced significant forest fires and mega-fires across multiple regions, leading to human casualties and damage to the natural environment, infrastructure, livestock, and agriculture. The current study aims to assess the ecosystem condition in terms of the natural regeneration and soil conditions of an area burnt by a forest fire (2021), specifically in the Ancient Olympia region situated in West Peloponnese (Ilia Prefecture), Greece. A standardized field sampling methodology was applied to record natural regeneration at chosen sites where a forest fire had also previously occurred (in 2007), resulting in the natural re-growth of the Pinus halepensis forest. Furthermore, an analysis was conducted on the geochemical, mineralogical, and sedimentological properties of soils obtained from this location. The findings of the research demonstrate the decline in the established natural regeneration of the Pinus halepensis forest and the overall tree layer. Species characteristic of post-fire ecological succession were observed in the shrub and herb layers, displaying varying coverage. The examination of soil mineralogy, sedimentology, and geochemistry indicated that the soil characteristics in the area are conducive to either natural or artificial regeneration. Ultimately, recommendations for landscape rehabilitation strategies are provided to inform decision-making processes, considering future climate conditions. [ABSTRACT FROM AUTHOR]

In educational research, the availability of a validated version of an original instrument in a different language offers the possibility for valid measurements obtained within the specific educational context and in addition it provides the opportunity for valid cross-cultural comparisons. The present study aimed to adapt the Science Motivation Questionnaire II (SMQ II) for application to a different cultural context (Greece), a different age group (secondary school students) and with a focus on chemistry learning. Subsequently, the Greek version of Chemistry Motivation Questionnaire II (Greek CMQ II) was used in order to investigate Greek secondary school students' motivation to learn chemistry for the first time. The sample consisted of 330 secondary school students (163 boys-167 girls), of which 146 were in lower secondary school (14-15 years old) and 184 were in upper secondary school (16-17 years old). Confirmatory factor analyses provided evidence for the validity of Greek CMQ II, as well as for configural, metric and scalar invariance, thus allowing meaningful comparisons between groups. The five motivation components of the original instrument namely grade motivation, career motivation, intrinsic motivation, self-efficacy, and self-determination were confirmed. Gender-based comparisons showed that girls had higher self-determination relative to the boys irrespective of the age group. In addition, girls in lower secondary school had higher career and intrinsic motivation relative to the boys of the same age group. Age-based comparisons showed that lower secondary school students had higher grade motivation relative to upper secondary school students.

This study aims at identifying factors that influence students' choice not to pursue a chemistry-related career by analyzing the experiences of secondary education chemistry teachers in Greece and of Greek adults who have not pursued studies related to science. Data collection was done with the method of individual structured interviews. The comparative analysis of the answers given by 10 adults and 10 chemistry teachers, shows that there is a noteworthy agreement between the factors pointed out by the two independent groups. These factors--proposed to form an interconnected grid--are related to the following issues: the nature of school chemistry, the instructional content and context, the students' characteristics and the status of chemistry in the Greek educational system and Greek society. (Contains 2 tables and 1 figure.)

The spectra of the [S.sub.1][Y.sub.Z] intermediate obtained are compared by visible light excitation of the [S.sub.1] state at liquid He temperatures or by near-infrared (NIR) light excitation of the [S.sub.2] state. The results validate the assignment of [S.sub.1][Y.sub.Z] to a true [S.sub.1] to [S.sub.2] intermediate and imply that the heterogeneity observed in [S.sub.2] is already present in [S.sub.1].

Research has been conducted on the heme-contained electron-transfer protein cytochrome c (sub)5. The relaxation properties of this cytochrome have been investigated via a Model-Free analysis.

A new study investigates the local mobility of the reduced and oxidized forms of rat microsomal cytochrome b5, using rotating frame 15N relaxation NMR measurements. Detailed study of the data shows different local mobility along the backbone nitrogens for both oxidized and reduced cytochrome. Such differential is thought to be important in the control of molecular recognition process involving cytochrome b5.

The cytochrome c6 of the photosynthetic algae Monoraphidium braunii is a protein consisting of 89 amino acid involved in the electron transport chain. Unlike the cytochrome c6 of yeasts and horses, that of M. braunii is negatively charged. A combination of spectroscopic analyses were employed in the elucidation of the solution structure of the oxidized form of this cytochrome. Results reveal that the oxidized structure is very similar to that of the reduced form.

Saturation-recovery electronic paramagnetic resonance (EPR) spectroscopy is utilized to examine the magnetic attributes and location of two forms of the S2 state of photosystem II (PSII). These include the altered multiline EPR signal species in NH3-treated PSII and the multiline EPR signal species in untreated PSII. Test results support findings regarding the asymmetric location of the Mn4 cluster as regards the redox-active tyrosines found in PSII.

The use of dinucleating bis(carboxylato) ligand XDX and phenoxyl radical ligand BIDPhE enables the synthesis of the phenoxyl radical diiron complex (Fe2O(XDK)(MeOH5)(H2O))(NO3)2). The radical diiron complex is an active site in the R2 protein of ribonucleotide reductase. The diiron complex is obtained as a stable solid.

Saturation-recovery EPR spectroscopic studies on photosystem II (PSII) membranes of spinach and on PSII core complexes of cyanobacterium Synechocystis sp. PCC 6803 reveal the symmetric location of tyrosines D and Z, relative to the non-heme Fe(II) in Mn-depleted photosystem II. The spin-lattice relaxation for both the YD and YZ radicals are increased by non-heme Fe(II). Spectral data confirm the presence of a C2 symmetry axis among the chromophores of PSII.

Saturation-recovery and progressive microwave power saturation EPR spectroscopic studies of the determination of the location of chlorophyll(z) in photosystem II (PSII) reveal that chlorophyll(z) resides on the hydrophobic surface of the D1/D2 complex. This location is in close association with Cyt b559. This proximity explains the fast reduction of Chl(z+) by Cyt b(559). Chl(z) is not analogous to the 'voyeur' monomer bacteriochlorophylls of the bacterial reaction center.

Trapping of intermediates of the S-state transitions that involve the tyrosyl radical is of ultimate importance, as they can test critical models employing a role of tyrosine (Tyr Z) in proton protein transfer, and provide important clues about the mechanism of water oxidation. Details on the observations of the trapping of metalloradical intermediates of the S-state transitions, at liquid helium temperatures are discussed.

The near-infra red excitation of the S(sub)2 state at liquid helium temperatures produces metalloradical intermediates assigned to S(sub)1Y(sub)z, suggesting a proton exchange between tyrosine Z and the manganese cluster and alteration of the magnetic properties of the manganese cluster.

The pulsed electron paramagnetic resonance (EPR) method of saturation recovery was used to examine the effect of dark adaptation on the magnetic properties of the Mn site in the O2-evolving center of photosystem II.The spin-lattice relaxation of the stable tyrosine radical of ribonucleotide reductase from Escherichia coli was demonstrated to serve as a probe of the magnetic properties of the EPR-silent dinuclear Fe(III) center. Moreover, the results indicate that the Mn cluster structure is tetrameric.

The S2 state of the oxygen-evolving complex (OEC) of photosystem II is heterogeneous, exhibiting two main EPR spectral forms, the multiline and the g = 4.1 signal. It is not clearly established whether this heterogeneity develops during the to S1 to S2 transition or is already present in the precursor states. We have compared the spectra of the S1YZ• intermediate, obtained by visible light excitation (induction of charge separation) of the S1 state at liquid He temperatures, (S1YZ•)vis, or by near-infrared (NIR) light excitation of the S2 state (utilization of the unusual property of the Mn cluster to act as an oxidant of Ys when excited by NIR), (S1YZ•)NIR. The decay kinetics of the (S1YZ•)vis spectrum at II K was also studied by the application of rapid-scan EPR. The two spectra share in common a signal with a characteristic feature at g = 2.035, but the (S1YZ•)vis spectrum contains in addition a fast decaying component 26 G wide. The analysis of the surface of the rapid-scan spectra yielded 270 ± 35 and 90 ± 15 s for the respective half-times of the two components of the (S1YZ•)vis spectrum at 11 K. (S1YZ•)vis advances efficiently to S2 when annealed at 200 K; notably the g = 2.035 signal advances to the multiline while the 26 G component advances to the g = 4.1 conformation. The "26 G" component is absent or very small, respectively, in thermophilic cyanobacteria or glycerol-containing spinach samples, in correlation to vanishing or very small amounts of the g = 4.1 component in the S2 spectrum. The results validate the assignment of S1YZ• to a true S1 to S2 intermediate and imply that the heterogeneity observed in S2 is already present in S1. Tentative valences are assigned to the individual Mn ions of the OEC in the two heterogeneous conformations of S1. [ABSTRACT FROM AUTHOR]

Near-IR (NIR) excitation at liquid He temperatures of photosystem II (PSII) membranes from the cyanobacterium Synechococcus vulcanus or from spinach poised in the S[sub 2] state results in the production of a g = 2.035 EPR resonance, reminiscent of metalloradical signals. The signal is smaller in the spinach preparations, but it is significantly enhanced by the addition of exogenous quinones. Ethanol (2-3%, v/v) eliminates the ability to trap the signal. The g = 2.035 signal is identical to the one recently obtained by Nugent et al. by visible-light illumination of the S l state, and preferably assigned to S[sub 1]Y[sub Z, sup •] [Nugent, J. H. A., Muhiuddin, I. P., and Evans, M. C. W. (2002) Biochemistry 41, 4117-4126]. The production of the g = 2.035 signal by liquid He temperature NIR excitation of the S[sub 2] state is paralleled by a significant reduction (typically 40-45% in S. vulcanus) of the S[sub 2] state multiline signal. This is in part due to the conversion of the Mn cluster to higher spin states, an effect documented by Boussac et al. [Boussac, A., Un, S., Homer, O., and Rutherford, A. W. (1998) Biochemistry 37, 4001-4007], and in part due to the conversion to the g = 2.035 configuration. Following the decay of the g = 2.035 signal at liquid helium temperatures (decay halftimes in the time range of a few to tens of minutes depending on the preparation), annealing at elevated temperatures (-80 °C) results in only partial restoration of the S2 state multiline signal. The full Size of the signal can be restored by visible-light illumination at -80 °C, implying that during the near-IR excitation and subsequent storage at liquid helium temperatures recombination with Q[sub A, sup -] (and therefore decay of the S[sub 2] state to the S[sub 1] state) occurred in a fraction of centers. In support of this conclusion, the g = 2.035 signal remains stable for several hours (at 11 K) in centers poised in the S[sub 2]···Q[sub A]... [ABSTRACT FROM AUTHOR]

Examines the solution structure of the B form for oxidized rat microsomal cytochrome b[sub5]. Administration of nuclear magnetic resonance to solve solution structure of proteins; Characterization of high quality and good resolution; Comparison on the structural and dynamic changes in the oxidation states.