The bioluminescent reaction of the "sea firefly" Cypridina hilgendorfii is a prototypical system for marine bioluminescence, as its substrate possesses an imidazopyrazinone core that is a common link among organisms of eight phyla. The elucidation of the mechanism behind Cypridina bioluminescence is essential for future applications in bioimaging, biomedicine, and bioanalysis. In this study we have investigated the key step of chemiexcitation with a combined experimental and theoretical approach. The obtained results indicate that neutral dioxetanone is responsible for efficient chemiexcitation, as the thermolysis of this species gives access to a long region of the potential energy surface (PES), where the ground and excited singlet states are degenerated. Contrary to expected, neither chemically induced electron-exchange luminescence (CIEEL) nor charge transfer-initiated luminescence (CTIL) can be used to explain imidazopyrazinone-based bioluminescence, as there is no clear relationship between electron (ET)/charge (CT) transfer (occurring between the electron-rich moiety and dioxetanone) and chemiexcitation. Attractive electrostatic interactions between the CO and oxyluciferin moieties allow neutral dioxetanone to spend time in the PES region of degeneracy, while repulsive interactions for anionic dioxetanone lead to a quicker CO detachment.

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Group work is an essential activity during both graduate and undergraduate formation. Students develop a set of skills, and employ criticism which helps them to better handle future interpersonal situations. There is a vast theoretical literature and numerous case studies about group work, but we haven't yet seen much development concerning the assessment of individual group participants. It is not always easy to have the perception of each student contribution to the whole work. Nevertheless, more than frequently, the assessment of the group is transposed to each group participant, which in turn results in each student having the same final mark. We propose and describe a tool to manage and assess individual group work taking into account the amount of work, interaction, quality, and the temporal evolution of each group participant. The module features the possibility to create two types of activities: collaborative or cooperative group work. We describe the conceptual design of our tool and present the two operating modes of the module, which is based on events, alerts and conditions. We then describe the methodology for the assessment in the two operating modes and how these two major approaches can be deployed through our module into pedagogical situations.