Given its non-invasive nature, there is increasing interest in the use of transcutaneous vagus nerve stimulation (tVNS) across basic, translational and clinical research. Contemporaneously, tVNS can be achieved by stimulating either the auricular branch or the cervical bundle of the vagus nerve, referred to as transcutaneous auricular vagus nerve stimulation(VNS) and transcutaneous cervical VNS, respectively. In order to advance the field in a systematic manner, studies using these technologies need to adequately report sufficient methodological detail to enable comparison of results between studies, replication of studies, as well as enhancing study participant safety. We systematically reviewed the existing tVNS literature to evaluate current reporting practices. Based on this review, and consensus among participating authors, we propose a set of minimal reporting items to guide future tVNS studies. The suggested items address specific technical aspects of the device and stimulation parameters. We also cover general recommendations including inclusion and exclusion criteria for participants, outcome parameters and the detailed reporting of side effects. Furthermore, we review strategies used to identify the optimal stimulation parameters for a given research setting and summarize ongoing developments in animal research with potential implications for the application of tVNS in humans. Finally, we discuss the potential of tVNS in future research as well as the associated challenges across several disciplines in research and clinical practice.

The bioinspired polymer polydopamine is synthesized and deposited on semiconductive glass substrates under different synthesis conditions (pH and oxidant type). Electrochemical methods are used to verify polymer deposition on the substrate and to examine the charge transfer properties of the obtained coatings. The presence of aromatic rings from the polymer is assessed by Raman spectroscopy. The experiment was designed to fit within a physical chemistry course and can also be suitable for courses on polymers, materials science, and electrochemistry.

The understanding of oxidized species derived from the neurotransmitter dopamine (DA) is a relevant topic for both the medical field (Parkinson’s disease) as well as for the field of materials science where the formation process of polydopamine (PDA) films is an active area of research. Polymers that interact strongly with almost all surfaces but have a low electrical conductivity have been obtained by the chemical oxidation of DA. Since electrical conductivity is a desired property for several applications, deposition alternatives such as electrochemical PDA synthesis have been proposed, but the results are still insufficient. In this context, we propose a new PDA chemical–electrochemical deposition process on glassy carbon electrodes. The chemical oxidation step that converts dopamine into dopamine-o-quinone previous to the electrochemical deposition was crucial to decrease the precursor concentration to the micromolar range. The PDA-like films synthesized by this method had high adhesion and low charge-transfer resistance, which was evidenced by impedance measurements and the successful electrodeposition of a polypyrrole coating on top of a PDA-like film. In addition, we observed that anodization of GC surfaces increases sensitivity toward six electroactive couples derived from DA oxidation in the pH regimes studied. These results show the complexity of the intermediates formed during the electrochemical polymerization of PDA.

This study aimed to examine the fractal properties of the optimal hydraulic gradient surface (OHGS), a geometrical body that describes the way in which the available energy should be spent within a water distribution network to ensure the calculation of a minimum capital cost design. For this purpose, multiple benchmark and Colombian systems were optimized and then analyzed to compute the fractal dimension of the OHGS and of the underlying structure of each network, which included the examination of randomly generated nonoptimal designs to recognize the differences in the fractal behavior of a least-cost and a more expensive solution. The results showed a dependency between the fractal properties of the OHGS and those of the topological structure, flow, and energy distribution inside the corresponding optimized network. Moreover, it was found that the degree of irregularity of the OHGS tended to be higher compared to a nonoptimal energy dissipation pattern. This suggests the applicability of the fractal analysis in optimization and operational improvement procedures.

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