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We report guiding and manipulation of charged particle beams by means of electrostatic optics based on a principle similar to the electrodynamic Paul trap. We use hundreds of electrodes fabricated on planar substrates and supplied with static voltages to create a ponderomotive potential for charged particles in motion. Shape and strength of the potential can be locally tailored by the electrodes' layout and the applied voltages, enabling the control of charged particle beams within precisely engineered effective potentials. We demonstrate guiding of electrons and ions for a large range of energies (from 20 to 5000 eV) and masses (5E-4 to 131 atomic mass units) as well as electron beam splitting as a proof-of-concept for more complex beam manipulation. Simultaneous confinement of charged particles with different masses is possible, as well as guiding of electrons with energies in the keV regime, and the creation of highly customizable potential landscapes, which is all hard to impossible with conventional electrodynamic Paul traps., Main text: 4 pages, 4 figures; Supplementary Material: 3 pages, 4 figures; in total: 7 pages, 8 figures

Work on establishing tiny malagasy primate as a new systems neuroscience animal model. Transferring experimental techniques from rodents to primates, developing behavioural paradigms, establishing surgeries and exploring capabilities of the mouse lemur led me to be involved in several research projects. As for the topic of my thesis, I chose to focus on spatial navigation and orientation. Self-perception in space is a long-debated topic and has been scientifically studied since the invention of analytic philosophy in the late 19th century. Orientation and navigation in space are among the main features characterizing animal behavior. Indeed, most animals spend a substantial part of their awake time trying to reach a specific location. Changing location increases the chance of finding mates, food, seeking better environmental conditions, or escaping predators and within-species competition. How does an organism know where it is going? How will it come back? And why is it lost now and then? These questions have been extensively studied in various animal species and have led to fundamental insights into the computational processes that underlie spatial navigation. This research project attempts to tackle a new aspect of navigation, namely the third dimension of space. Exploring arboreal environments has probably been a main driver behind primate evolution, thus understanding how three dimensional space is represented in the primate brain seems to be a pertinent question. At the heart of this study is a small and arboreal mammal, which has retained many of the hallmarks of early primates: the gray mouse lemur (Microcebus murinus). This malagasy prosimian weighs only 60gr and thus facilitates the holding and handling compared to other, larger primates. In addition, it allows the direct transfer of many experimental tools initially designed for rodents.

Elektronen- und Ionenstrahlen sind unverzichtbare Werkzeuge in zahlreichen Bereichen der Wissenschaft und Technik, zu denen unter anderem die Strahlentherapie, die Mikroskopie und die Lithografie gehören. In dieser Arbeit wird über das Führen und Aufteilen von Strahlen geladener Teilchen mithilfe von ponderomotorischen Potentialen berichtet. Aufbauend auf den bisher einlagigen Mikrowellenstrukturen wurde ein Elektronenstrahlteiler entwickelt, der aus zwei Leiterplatten besteht und das Aufteilen eines Elektronenstrahls für Elektronenenergien bis zu 200 eV erlaubt. Es wurden zusätzlich elektrostatische Pendants zu den Mikrowellenfallen und Strahlteilern entwickelt, die, obwohl sie technisch anders aufgebaut sind, auf dem gleichen physikalischen Prinzip beruhen. Diese elektrostatischen Instrumente können geladene Teilchen mit sehr unterschiedlichen Massen in hochgradig einstellbaren Potentialen führen, deren Form und Stärke lokal durch das Layout der lithografisch hergestellten Elektroden und die angelegten Spannungen eingestellt werden können. Es werden Messungen gezeigt, die das Führen von Elektronen und Ionen für einen großen Energie- und Massenbereich (von 20 bis 5000 eV und von 5⋅10-4 bis 131 u) sowie die Aufspaltung von Elektronenstrahlen in zwei Ausgangsstrahlen für Energien bis in den Kiloelektronenvolt-Bereich demonstrieren. Es wird theoretisch gezeigt, dass die Miniaturisierung dieser elektrostatischen Strukturen zu größeren Fallenfrequenzen und damit zu größeren Energieabständen zwischen den Bewegungszuständen der Teilchen in den effektiven Potentialen führt, wodurch in zukünftigen Experimenten mit Elektronenstrahlen quantenmechanische Phänomene beobachtbar werden sollten. Zusätzlich wurde in Analogie zu einer linearen Paul-Falle ein elektrostatischer Resonator für Elektronenstrahlen entwickelt und ein Experiment aufgebaut, um mehrere Umläufe der Elektronen in diesem Resonator nachzuweisen. Die Messungen mit dem Resonator wurden zum Zeitpunkt des Verfassens dieser Arbeit noch nicht beendet, jedoch konnten in der ersten Messreihe bis zu drei Umläufe von Elektronen im Resonator nachgewiesen werden.

The exposure of metal sulfides to air or water, either produced naturally or due to mining activities, can result in environmentally damaging acid mine drainage (AMD). This needs to be accurately monitored and remediated. In this study, we apply high-resolution unmanned aerial system (UAS)-based hyperspectral mapping tools to provide a useful, fast, and non-invasive method for the monitoring aspect. Specifically, we propose a machine learning framework to integrate visible to near-infrared (VNIR) hyperspectral data with physicochemical field data from water and sediments, together with laboratory analyses to precisely map the extent of acid mine drainage in the Tintillo River (Spain). This river collects the drainage from the western part of the Rio Tinto massive sulfide deposit and discharges large quantities of acidic water with significant amounts of dissolved metals (Fe, Al, Cu, Zn, amongst others) into the Odiel River. At the confluence of these rivers, different geochemical and mineralogical processes occur due to the interaction of very acidic water (pH 2.5–3.0) with neutral water (pH 7.0–8.0). This complexity makes the area an ideal test site for the application of hyperspectral mapping to characterize both rivers and better evaluate contaminated water bodies with remote sensing imagery. Our approach makes use of a supervised random forest (RF) regression for the extended mapping of water properties, using the samples collected in the field as ground-truth and training data. The resulting maps successfully estimate the concentration of dissolved metals and related physicochemical properties in water, and trace associated iron species (e.g., jarosite, goethite) within sediments. These results highlight the capabilities of UAS-based hyperspectral data to monitor water bodies in mining environments, by mapping their hydrogeochemical properties, using few field samples. Hence, we have demonstrated that our workflow allows the rapid discrimination and mapping of AMD contamination in water, providing an essential basis for monitoring and subsequent remediation.

Objectives/Interrogation: According to literature squamous cell carcinoma is the most frequent malignant tumor of the hand with 58-90%. In particular organ transplant patients have a 65 to 200 times greater risk of developing squamous cell carcinoma with more aggressive progression compared[for full text, please go to the a.m. URL], 14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT)

Objectives/Interrogation: The diagnosis of melanoma oft he hand is associated with a poor prognosis. While the surgical management of melanoma is following distinct guidelines, there are no specific considerations regarding functional areas of the hand or subungual melanoma. It was shown by literature,[for full text, please go to the a.m. URL], 14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT)