Direct probing of photoinduced electron transfer in a self- assembled biomimetic [2Fe2S]-hydrogenase complex using ultrafast vibrational spectroscopy

A pyridyl-functionalized diiron dithiolate complex, [μ-(4-pyCH2−NMI-S2)Fe2(CO)6] (3, py = pyridine(ligand), NMI = naphthalene monoimide) was synthesized and fully characterized. In the presence of zinc tetraphenylporphyrin (ZnTPP), a self-assembled 3·ZnTPP complex was readily formed in CH2Cl2 by the coordination of the pyridyl nitrogen to the porphyrin zinc center. Ultrafast photoinduced electron transfer from excited ZnTPP to complex 3 in the supramolecular assembly was observed in real time by monitoring the ν(CO) and ν(CO)NMI spectral changes with femtosecond time-resolved infrared (TRIR) spectroscopy. We have confirmed that photoinduced charge separation produced the monoreduced species by comparing the time-resolved IR spectra with the conventional IR spectra of 3•− generated by reversible electrochemical reduction. The lifetimes for the charge separation and charge recombination processes were found to be τCS = 40 ± 3 ps and τCR = 205 ± 14 ps, respectively. The charge recombination is much slower than that in an analogous covalent complex, demonstrating the potential of a supramolecular approach to extend the lifetime of the chargeseparated state in photocatalytic complexes. The observed vibrational frequency shifts provide a very sensitive probe of the delocalization of the electron-spin density over the different parts of the Fe2S2 complex. The TR and spectro-electrochemical IR spectra, electron paramagnetic resonance spectra, and density functional theory calculations all show that the spin density in 3•− is delocalized over the diiron core and the NMI bridge. This delocalization explains why the complex exhibits low catalytic dihydrogen production even though it features a very efficient photoinduced electron transfer. The ultrafast porphyrin-to-NMIS2−Fe2(CO)6 photoinduced electron transfer is the first reported example of a supramolecular Fe2S2-hydrogenase model studied by femtosecond TRIR spectroscopy. Our results show that TRIR spectroscopy is a powerful tool to investigate photoinduced electron transfer in potential dihydrogen-producing catalytic complexes, and that way to optimize their performance by rational approaches.

Elucidating the structure of chiral molecules by using amplified vibrational circular dichroism: from theory to experimental realization

Recent experimental observations of enhanced vibrational circular dichroism (VCD) in molecular systems with low-lying electronically excited states suggest interesting new applications of VCD spectroscopy. The theory describing VCD enhancement through vibronic coupling schemes was derived by Nafie in 1983, but only recently experimental evidence of VCD amplification has demonstrated the extent to which this effect can be exploited as a structure elucidation tool to probe local structure. In this Concept paper, we give an overview of the physics behind vibrational circular dichroism, in particular the equations governing the VCD amplification effect, and review the latest experimental developments with a prospective view on the application of amplified VCD to locally probe biomolecular structure.

Redox-sensitive prosurvival and proapoptotic protein expression in the myocardial remodeling post-infarction in rats

In this study, we investigated the oxidative stress influence in some prosurvival and proapoptotic proteins after myocardial infarction (MI). Male Wistar rats were divided in two groups: Sham-operated (control) and MI. MI was induced by left coronary artery occlusion. 28-days after surgery, echocardiographic, morphometric, and hemodynamic parameters were evaluated. Redox status (reduced to oxidized glutathione ratio, GSH/GSSG) and hydrogen peroxide levels (H(2)O(2)) were measured in heart tissue. The p-ERK/ERK, p-Akt/Akt, p-mTOR/mTOR and p-GSK-3 beta/GSK-3 beta ratios, as well as apoptosis-inducing factor (AIF) myocardial protein expression were quantified by Western blot. MI group showed an increase in cardiac hypertrophy (23%) associated with a decrease in ejection fraction (38%) and increase in left ventricular end-diastolic pressure (82%) when compared to control, characterizing ventricular dysfunction. Redox status imbalance was seen in MI animals, as evidenced by the decrease in the GSH/GSSG ratio (30%) and increased levels of H(2)O(2) (45%). This group also showed an increase in the ERK phosphorylation and a reduction of Akt and mTOR phosphorylation when compared to control. Moreover, we showed a reduction in the GSK-3 beta phosphorylation and an increase in AIF protein expression in MI group. Taken together, our results show increased H(2)O(2) levels and cellular redox imbalance associated to a higher p-ERK and AIF immunocontent, which would contribute to a maladaptive hypertrophy phenotype.

Scope for further analytical solutions for constant flux infiltration into a semi-infinite soil profile or redistribution in a finite soil profile.

We attempt to generate new solutions for the moisture content form of the one-dimensional Richards' [1931] equation using the Lisle [1992] equivalence mapping. This mapping is used as no more general set of transformations exists for mapping the one-dimensional Richards' equation into itself. Starting from a given solution, the mapping has the potential to generate an infinite number of new solutions for a series of nonlinear diffusivity and hydraulic conductivity functions. We first seek new analytical solutions satisfying Richards' equation subject to a constant flux surface boundary condition for a semi-infinite dry soil, starting with the Burgers model. The first iteration produces an existing solution, while subsequent iterations are shown to endlessly reproduce this same solution. Next, we briefly consider the problem of redistribution in a finite-length soil. In this case, Lisle's equivalence mapping is generalized to account for arbitrary initial conditions. As was the case for infiltration, however, it is found that new analytical solutions are not generated using the equivalence mapping, although existing solutions are recovered.

The Civic School : Australian-Indonesian professional collaboration to model and audit the development of democratic primary classrooms and teacher language using the index for inclusion

The study is a pilot project in Australian-Indonesian institutional collaboration for the professional development of primary school teachers in West Sumatra in citizenship education. Senior staff in the department of Pancasila and Citizenship Education at the State University of Padang (UNP), West Sumatra initiated the project. UNP staff sought the collaboration of the Faculty of Education at the University of Tasmania for bringing about and sustaining changes in teacher practice needed to implement the new civic goals in the 1999 Suplemen. The Index for Inclusion was used to model and audit the development of democratic primary classrooms and language use in a cluster of Padang schools in West Sumatra. The paper describes the background to the project and how the Index for Inclusion was understood during the initial two-week implementation phase by teachers and school principals. The significance of the study lies in the potential of the Index for Inclusion internationally to citizenship education, a field of education that was not considered in the initial development of the Index project and the contribution of the multiple fields of inquiry to the evolving theoretical understandings of inclusive education.

'I do lots of things that the University would not approve of'. What counts as professional knowledge in the eyes of pre-service and beginning teachers -implications of the encounter for the role of teacher educators in pre-service middle school preparati

This paper is an account of teacher educator perceptions of the take-up by beginning teachers of the values and practices advocated in pre-service education. Methodologically grounded in a critical ethnographic account, two teacher educator/researchers retell their understanding of the one-month experience as middle school classroom teachers in an allocated school. The paper examines the consequences of what counts as professional knowledge in the eyes of pre-service and beginning teachers and the implications of the encounter for the role of teacher educators in preservice preparation. The purpose of the research is to consider the well-researched issue of the rejection of academic training (to greater or lesser extents) that is experienced by very many preservice and beginning teachers at some stage after experience in schools. As an exemplary colleague teacher said to us as we negotiated our participation in the school: "I do lots of things that the University would not approve of". Our argument is that teacher education needs the kind of participatory inquiry represented by the undertaking and methodology of this project. The paper is the 'primary record' (Carspecken 1996) of the research and works to open the next phase, the dialogical stage of the research process.

Reading for meaning : problematizing inclusion in Indonesian civic education

This paper reports on the use of the Index for Inclusion in five socioeconomically different primary school contexts in Indonesia. The research was designed and developed through Australian and Indonesian teachers and teacher educators collaborative efforts over a year. The work took place during the post‐Suharto reform period and focuses on the field of Civics education. The research examines what the ethic of inclusion means to teachers participating in political and educational democratization as they attempt to embrace and develop citizenship classroom practices that feature respect for difference. The theoretical interest is in both citizenship theory and inclusion; showing how the civic cultures of school and nation intersect; and the implications of that intersection for inclusion theory and cross‐cultural theorizing of inclusion more broadly.

Negations generated by bounded lattices t-norms

From the birth of fuzzy sets theory, several extensions have been proposed changing the possible membership values. Since fuzzy connectives such as t-norms and negations have an important role in theoretical as well as applied fuzzy logics, these connectives have been adapted for these generalized frameworks. Perhaps, an extension of fuzzy logic which generalizes the remaining extensions, proposed by Joseph Goguen in 1967, is to consider arbitrary bounded lattices for the values of the membership degrees. In this paper we extend the usual way of constructing fuzzy negations from t-norms for the bounded lattice t-norms and prove some properties of this construction.