Entwicklung eines opto-mechanischen Mikrolabors zur Generierung und Untersuchung biomimetischer Proteinnetzwerke

Der Zugang zur Untersuchung komplexer Mikrostrukturen, wie sie insbesondere durch biologische Systeme gebildet werden, verlangt spezielle Werkzeuge und Methoden, die eine aktive physikalische und chemische Kontrolle in diesem Größenbereich und die Erfassung systemspezifischer Parameter erlauben. Ein Teil dieser Anforderungen kann durch den Einsatz holographischer optischer Pinzetten (HOT) erfüllt werden, mit denen sich eine Vielzahl mikroskopischer Objekte nicht-invasiv manipulieren und Piconewtonkräfte messen lassen. In dieser Arbeit wurden die Anwendungsmöglichkeiten der HOT erstmals über eine reine Objektmanipulation hinaus durch Integration in eine neu entwickelte Mikrofluidikplattform erweitert und die HOT-Technologie in Hinblick auf komplexe Systemanwendungen weiterentwickelt: Verschiedene Algorithmen zur Hologrammberechnung wurden hinsichtlich ihrer Effizienz miteinander verglichen. Es konnte gezeigt werden, dass ein hier vorgestellter erweiterter Superpositionsansatz in den meisten Fällen zur Hologrammgenerierung ausreicht, womit die Verwendung zeitaufwändiger iterativer Verfahren entfällt. Die Abhängigkeit der Effizienz von Symmetrieeigenschaften der Fallenmuster wurde aufgezeigt und analysiert. Durch Verwendung der Superposition wurde eine Ortsauflösung der HOT-Positionierung im Nanometerbereich realisiert. Die Abhängigkeit der Auflösung von der Zahl der Bildpunkte und Phasenstufen der Hologramme konnte hergeleitet und experimentell demonstriert werden. Die HOT-Technologie ermöglicht die Erzeugung optischer Wirbelfallen, die gefangene Objekte durch Drehimpulsübertragung in Rotation versetzen. Eine neue Klasse modulierter optischer Wirbel wurde präsentiert, die eine Regulation des Drehimpuls optischer Wirbel erlaubt ohne die Laserintensität oder den Wirbelradius zu verändern. Die Fabrikation eines ultraflachen und optisch transparenten Mikrofluidiksystems stellt ein Werkzeug zur Kontrolle des chemischen Milieus zur Verfügung, das eine Integration der HOT erlaubte. Speziell auf die HOT angepasste Kanaldesigns wurden entwickelt, um Systemstabilität zu gewährleisten und gleichzeitig einen flexiblen Austausch von Substanzen zu ermöglichen. Dieses opto-mechanische Mikrolabor konnte schließlich zur Generierung biomimetischer quasi-zweidimensionaler Aktinnetzwerke auf durch HOT strukturierten Mikrokugeln genutzt werden: Es wurde zur Oberflächenstrukturierung, der Erzeugung kraftsensorischer Geloberflächen und der freien rein optischen Systemmanipulation eingesetzt

A hexapod walker using a heterarchical architecture for action selection

Schilling M, Paskarbeit J, Hoinville T, et al. A hexapod walker using a heterarchical architecture for action selection. Frontiers in Computational Neuroscience. 2013;7:126.Moving in a cluttered environment with a six-legged walking machine that has additional body actuators, therefore controlling 22 DoFs, is not a trivial task. Already simple forward walking on a flat plane requires the system to select between different internal states. The orchestration of these states depends on walking velocity and on external disturbances. Such disturbances occur continuously, for example due to irregular up-and-down movements of the body or slipping of the legs, even on flat surfaces, in particular when negotiating tight curves. The number of possible states is further increased when the system is allowed to walk backward or when front legs are used as grippers and cannot contribute to walking. Further states are necessary for expansion that allow for navigation. Here we demonstrate a solution for the selection and sequencing of different (attractor) states required to control different behaviors as are forward walking at different speeds, backward walking, as well as negotiation of tight curves. This selection is made by a recurrent neural network (RNN) of motivation units, controlling a bank of decentralized memory elements in combination with the feedback through the environment. The underlying heterarchical architecture of the network allows to select various combinations of these elements. This modular approach representing an example of neural reuse of a limited number of procedures allows for adaptation to different internal and external conditions. A way is sketched as to how this approach may be expanded to form a cognitive system being able to plan ahead. This architecture is characterized by different types of modules being arranged in layers and columns, but the complete network can also be considered as a holistic system showing emergent properties which cannot be attributed to a specific module

Using a reinforcement learning approach in a discrete event manufacturing system

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Geology-structural position and specialization of granitoid the Amalat plateau

Представлены результаты изучения геолого-структурной позиции и специализации гранитоидов Амалатского плато. Определен минеральный и элементный состава гранитоидов фундамента. Установлено, что гранитоиды фундамента представлены лейкократовыми биотитовыми гранитами субщелочного ряда, определены основные породообразующие минералы, акцессорная минерализация (апатит, циркон, сфен, магнетит, монацит, ксенотим) и минералы носители урана. Установлена высокая радиоактивность гранитоидов фундамента торий-урановой и урановой природы. The results of the studying of Geology-structural position and specialization of granitoid the Amalat table land. The mineral and element structure of granitoids' base was stated. It has been stated that granitoids in basement consist of leucocratic biotite granite of subalkaline row. The major rock-forming, accessory (apatite, zircon, sphen, magnetite, monazite, xenotime),and uranium-bearing minerals have been determined. High radioactivity of basement granitoids of thorium-uranium and uranium origin was stated

Mice with targeted disruption of the fatty acid transport protein 4 (Fatp 4, Slc27a4) gene show features of lethal restrictive dermopathy

The fatty acid transport protein family is a group of evolutionarily conserved proteins that are involved in the cellular uptake and metabolism of long and very long chain fatty acids. However, little is known about their respective physiological roles. To analyze the functional significance of fatty acid transport protein 4 (Fatp4, Slc27a4), we generated mice with a targeted disruption of the Fatp4 gene. Fatp4-null mice displayed features of a neonatally lethal restrictive dermopathy. Their skin was characterized by hyperproliferative hyperkeratosis with a disturbed epidermal barrier, a flat dermal–epidermal junction, a reduced number of pilo-sebaceous structures, and a compact dermis. The rigid skin consistency resulted in an altered body shape with facial dysmorphia, generalized joint flexion contractures, and impaired movement including suckling and breathing deficiencies. Lipid analysis demonstrated a disturbed fatty acid composition of epidermal ceramides, in particular a decrease in the C26:0 and C26:0-OH fatty acid substitutes. These findings reveal a previously unknown, essential function of Fatp4 in the formation of the epidermal barrier

Hippocampal subfield volumes are nonspecifically reduced in premature‐born adults

Reduced global hippocampus volumes have been demonstrated in premature‐born individuals, from newborns to adults; however, it is unknown whether hippocampus subfield (HCSF) volumes are differentially affected by premature birth and how relevant they are for cognitive performance. To address these questions, we investigated magnetic resonance imaging (MRI)‐derived HCSF volumes in very premature‐born adults, and related them with general cognitive performance in adulthood. We assessed 103 very premature‐born (gestational age [GA] <32 weeks and/or birth weight <1,500 g) and 109 term‐born individuals with cognitive testing and structural MRI at 26 years of age. HCSFs were automatically segmented based on three‐dimensional T1‐ and T2‐weighted sequences and studied both individually and grouped into three functional units, namely hippocampus proper (HP), subicular complex (SC), and dentate gyrus (DG). Cognitive performance was measured using the Wechsler‐Adult‐Intelligence‐Scale (full‐scale intelligence quotient [FS‐IQ]) at 26 years. We observed bilateral volume reductions for almost all HCSF volumes in premature‐born adults and associations with GA and neonatal treatment intensity but not birth weight. Left‐sided HP, SC, and DG volumes were associated with adult FS‐IQ. Furthermore, left DG volume was a mediator of the association between GA and adult FS‐IQ in premature‐born individuals. Results demonstrate nonspecifically reduced HCSF volumes in premature‐born adults; but specific associations with cognitive outcome highlight the importance of the left DG. Data suggest that specific interventions toward hippocampus function might be promising to lower adverse cognitive effects of prematurity

Decreased cortical thickness mediates the relationship between premature birth and cognitive performance in adulthood

Cortical thickness (CTh) reflects cortical properties such as dendritic complexity and synaptic density, which are not only vulnerable to developmental disturbances caused by premature birth but also highly relevant for cognitive performance. We tested the hypotheses whether CTh in young adults is altered after premature birth and whether these aberrations are relevant for general cognitive abilities. We investigated CTh based on brain structural magnetic resonance imaging and surface‐based morphometry in a large and prospectively collected cohort of 101 very premature‐born adults (<32 weeks of gestation and/or birth weight [BW] below 1,500 g) and 111 full‐term controls at 26 years of age. Cognitive performance was assessed by full‐scale intelligence quotient (IQ) using the Wechsler Adult Intelligence Scale. CTh was reduced in frontal, parietal, and temporal associative cortices predominantly in the left hemisphere in premature‐born adults compared to controls. We found a significant positive association of CTh with both gestational age and BW, particularly in the left hemisphere, and a significant negative association between CTh and intensity of neonatal treatment within limited regions bilaterally. Full‐scale IQ and CTh in the left hemisphere were positively correlated. Furthermore, CTh in the left hemisphere acted as a mediator on the association between premature birth and full‐scale IQ. Results provide evidence that premature born adults have widespread reduced CTh that is relevant for their general cognitive performance. Data suggest lasting reductions in cortical microstructure subserving CTh after premature birth