Context. Radio occultation is a technique used to study planetary atmospheres by means of the refraction and absorption of a spacecraft carrier signal through the atmosphere of the celestial body of interest, as detected from a ground station on Earth. This technique is usually employed by the deep space tracking and communication facilities (e.g., NASA's Deep Space Network (DSN), ESA's Estrack). Aims. We want to characterize the capabilities of the Planetary Radio Interferometry and Doppler Experiment (PRIDE) technique for radio occultation experiments, using radio telescopes equipped with Very Long Baseline Interferometry (VLBI) instrumentation. Methods. We conducted a test with ESA's Venus Express (VEX), to evaluate the performance of the PRIDE technique for this particular application. We explain in detail the data processing pipeline of radio occultation experiments with PRIDE, based on the collection of so-called open-loop Doppler data with VLBI stations, and perform an error propagation analysis of the technique. Results. With the VEX test case and the corresponding error analysis, we have demonstrated that the PRIDE setup and processing pipeline is suited for radio occultation experiments of planetary bodies. The noise budget of the open-loop Doppler data collected with PRIDE indicated that the uncertainties in the derived density and temperature profiles remain within the range of uncertainties reported in previous Venus' studies. Open-loop Doppler data can probe deeper layers of thick atmospheres, such as that of Venus, when compared to closed-loop Doppler data. Furthermore, PRIDE through the VLBI networks around the world, provides a wide coverage and range of large antenna dishes, that can be used for this type of experiments.

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Injectable neurostimulators are currently applied in clinical trials to minimize the side effects such as discomfort, risk of infection, and post-surgery trauma, which can be pronounced with conventional, bulky implantable neurostimulators. Owing to its smaller
size, wireless-updatable software, and wireless power supply, the injectable neurostimulator is presumably less invasive, ‘smarter’, and has a longer lifetime. We discuss the concept and development of the injectable neurostimulator, persistent implementation challenges, and obstacles to be overcome in its evolution. We survey the use of new materials, technologies, and design methods for injectable electrodes, batteries, antennas, and packaging to enhance reliability and other features. These advances in the field are accompanied by progress in electrophysiology, neuroscience, neurology, clinical trials, and treatments.@en