Oxidation-reduction potentials of organic systems

Electroanalytical voltammetry in flowing solutions

The hippocampus is one of the most researched structures of the brain. Studies of lesions in humans, primates and rodents have suggested to some that the primary role of the hippocampus is to act as a temporary memory buffer which is required for the consolidation of long-term memory. The famous case study of patient H.M., in particular, seemed to suggest that the hippocampus was of crucial importance for memory formation. However, recordings of single neurons in freely moving rodents did not support this notion. In such recordings, neurons were found that were active predominately when the animal passed through a particular area in space. Consequently, these neurons were termed 'place cells' and a theory was developed that suggested that the hippocampus acts as a 'cognitive map' that is required for spatial orientation. It was then found that H.M. had significant damage to his temporal lobes that included the amygdala, rhinal cortices, and other areas. Further case studies and selective hippocampal lesions in primates resulted in much milder amnestic symptoms, and lesions of defined cortical areas in the temporal lobes showed that a number of functions previously attributed to the hippocampus were in fact linked to these areas. Further analysis of neuronal activity in the hippocampus showed that not only is spatial information represented there, but also additional information, such as speed of movement, direction of movement, match or non-match detection, olfactorial identification, and others. In addition, it was found that selective lesions of the hippocampus in rodents impaired spatial navigation and memory formation only mildly. Only simultaneous lesions of several cortical areas in conjunction with the hippocamus could reproduce the impairments and symptoms that were previously thought to be observed after hippocampal lesions alone. In conclusion it is proposed that information processing and memory formation is shared by several brain areas that act as a functional system. This review presents evidence from many different studies that the hippocampus is part of this system and plays a supportive role in associating complex multimodal information and laying down new memory traces. In addition, the concept of allocating specific functions (such as the development of a cognitive map) exclusively to the hippocampus is rejected.

Time, space and hippocampal functions.

The state of the art and challenges in developing in situ voltammetric probes for direct measurements in natural waters are presented. Articles dealing with this topic are reviewed. Use of voltammetric probes in the laboratory and in the field is outlined. An up-to-date account of the results reported in the literature on the development of existing in situ voltammetric systems for such measurements is given. Emphasis is placed on the need for such systems to gain a better understanding of the mechanisms of processes occurring in natural aquatic systems. Suggestions are made for future development.

In situ voltammetric measurements in natural waters: Future prospects and challenges

Self-assembled monolayers at electrode metal surfaces

Determination of N-nitrosamines by high-performance liquid chromatographic separation with voltammetric detection

Voltammaetric characterization of small platinum-iridium-based mercury film electrodes

A mercury drop electrode for use in electrochemical experiments. The invention includes a reservoir for liquid mercury, a mercury drop capillary having upper and lower open ends and also having a chemically inert lower capilalry tube portion and an electrically conductive upper capillary tube portion supported by the lower portion and in contact with the mercury in the reservoir, valve means including a valve stem having a seal at its lower end and a ferromagnetic portion at its upper end, a valve seat comprising the upper end of the upper portion of the capillary which acts in concert with the valve seal to close the valve, and actuating means operatively arranged to lift the valve seal from the seat to allow mercury to enter the capillary from the reservoir and to lower the seal to the seat to prevent mercury from entering the capillary from the reservoir.

Controlled-growth mercury drop electrode

Kinetics of cathodic reduction of adsorbed material: The reduction of midazolam at mercury electrodes

Commercial electrochemical instrumentation is in a state of mature development. Microprocessors are used mainly as devices for data handling, and there are no commercial computer-based instruments. Progress in the science and proliferation of applications depend on noninstrumental factors such as electrode materials.

Janet Osteryoung

Papers

Determination of N-nitrosamines by high-performance liquid chromatographic separation with voltammetric detection

Voltammaetric characterization of small platinum-iridium-based mercury film electrodes

Controlled-growth mercury drop electrode

Kinetics of cathodic reduction of adsorbed material: The reduction of midazolam at mercury electrodes

Developments in Electrochemical Instrumentation