University of Art and Design Offenbach

The rotating Ring Disk Electrode (RRDE), since its introductionin 1959 by Frumkin and Nekrasov, has become indispensable with diverseapplications in electrochemistry, catalysis, and material science.The collection efficiency () is an important parameter extracted fromthe ring and disk currents of the RRDE, providing valuable informationabout reaction mechanism, kinetics, and pathways. The theoreticalprediction of is a challenging task: requiring solutionof the complete convective diffusion mass transport equation withcomplex velocity profiles. Previous efforts, including by Albery andBruckenstein who developed the most widely used analytical equations,heavily relied on approximations by removing radial diffusion andusing approximate velocity profiles. 65 years after the introductionof RRDE, we employ a physics-informed neural network to solve thecomplete convective diffusion mass transport equation, to reveal theformerly neglected edge effects and velocity corrections on , and to provide a guideline where conventionalapproximation is applicable.

Several underlying conditions of moyamoya syndrome (MMS) are well established, but so far, D-2-hydroxyglutaric aciduria (D-2-HGA) has not been mentioned. We are the first to describe a case of a patient suffering from D-2-HGA developing MMS. The co-occurrence of D-2-HGA and MMS in a patient is reported. Furthermore, we describe the neurosurgical revascularization procedure performed and report on the follow-up. A 7-year-old girl suffering from D-2-HGA developed two transient ischemic attacks (TIAs). Using MRI/MRA and invasive angiography MMS was diagnosed. We performed an encephalo-duro-arterio-myo-synangiosis (EDAMS) as an indirect revascularization procedure first on the right and 2months later on the left hemisphere. We have followed her up until the age of 10. Since the second surgery, she has not suffered further TIAs and is in a better general medical condition. Even though children with D-2-HGA often suffer epileptic attacks, every new (transient) neurological deficit should be followed up by an MRI/MRA so as not to oversee a possible underlying MMS. After diagnosis, EDAMS in combination with acetylsalicylic acid (ASA) is recommended to prevent further ischemic events.