The role of Hand2 in branchial arch and head-shoulder patterning

Comprehending gnathostome evolution requires insights into key cellular and molecular components of craniofacial and shoulder development. For the work of this PhD, I made use of genetically modified mouse models to study aspects of mammalian head and shoulder morphogenesis by triple fluorescent RNA in situ hybridisation, immunohistochemistry and high resolution imaging. First- I use a genetically defined sentinel cell population labelled by the Hand2-Cre transgene to establish the expansion of the distal-most branchial arch domain and correlate this by triple fluorescent RNA in situ hybridisation with the system controlling proximo-distal branchial arch patterning, the Dlx system. I find that the axis of the Dlx system does not correspond to the proximo-distal but an endodermal-ectodermal axis of the arch and rotates during development; the overall expansion of the arch is explicable by telescopic outgrowth along this new axis. Second- I study the cellular and molecular characteristics of head/ shoulder skeleto-muscular connectivity and the contribution of limb lateral plate mesoderm to the shoulder girdle, which allows me to identify part of the manubrium sterni as the ‘lost’ mammalian procoracoid and to demonstrate that the interaction between lateral plate mesodermal subpopulations is non-random. Third- I establish novel roles for Hand2 in lower incisor ameloblasts and in laminar dermal bone formation, suggesting a fundamental role for Hand2 in epithelial and mesenchymal cell layer arrangements. My detailed study of the murine frontal bone reveals that the establishment of an internal and an external layer initiates dermal bone formation; the latter shows intermediate molecular periosteal/ perichondrial characteristics and generates the intermediate layer by a Hand2-dependent invagination process. For a comparative amphibian data set, I begin to establish genetic lineage labelling as technique in Xenopus tropicalis. I generate and test a Xenopus Hand2-Cre transgene and establish a stable generic Xenopus tropicalis Cre-reporter line by I-SceI mediated transgenesis

Measurement instruments for the early detection of unilateral cerebral palsy and evaluation of bimanual performance

Infants with early brain lesions are at risk of developing unilateral cerebral palsy (CP) and valid and reliable measurement instruments for their early detection as well as evaluation of their bimanual performance at later age are needed. Such identification allows for early family support and intervention, while evaluation of hand function at later ages enables to tackle primary challenges children and adolescents with unilateral CP face continuously while performing everyday activities that require the use of both hands. This thesis focuses on two measurement instruments, the Hand Assessment for Infants (HAI) and the Children’s Hand-use Experience Questionnaire (CHEQ), as applied to infants at risk of developing unilateral CP and children and adolescents with this condition, respectively. The overall aim was to determine the validity of HAI scores to predict unilateral CP and the ability of the CHEQ scores to capture perceptions of bimanual performance, both at a single point in time and over time, in comparison to other assessments serving as external criteria. The HAI is the first standardized test designed to evaluate both uni- and bimanual functions in infants from 3-12 months of age at risk of developing unilateral CP. In combination with neonatal magnetic resonance imaging, and considerations of gestational age and sex, the HAI can predict unilateral CP in infants with asymmetric perinatal brain injury as young as 3.5-4.5 months of age. In addition, HAI scores exhibit very good to excellent overall accuracy in predicting the development of unilateral CP in infants at risk at various time-points from 3.5-12 months of age. Impaired hand function presents a continuous challenge when performing daily activities requiring the use of both hands, especially as children with unilateral CP grow older. The CHEQ, is an online patient-reported questionnaire of how children and adolescents with unilateral hand impairment experience the use of the affected hand in connection with activities requiring both hands. The AHA is a standardized test based on observation of the use of the affected hand by children with unilateral CP during bimanual activities. The CHEQ and the AHA were found to measure different constructs that are only related to a minor extent, emphasizing the need to utilize both of these complementary tools to obtain a more complete picture of the perceived and observed performance of bimanual activities by children and adolescents with unilateral CP. The CHEQ scores captured some change in perceived bimanual performance, with good accuracy for the scale feeling bothered, but only limited accuracy for the scales grasp efficacy and time utilization. Consequently, CHEQ scores can be recommended primarily for describing perceived bimanual performance

Towards Efficient Full Pose Omnidirectionality with Overactuated MAVs

Omnidirectional MAVs are a growing field, with demonstrated advantages for aerial interaction and uninhibited observation. While systems with complete pose omnidirectionality and high hover efficiency have been developed independently, a robust system that combines the two has not been demonstrated to date. This paper presents VoliroX: a novel omnidirectional vehicle that can exert a wrench in any orientation while maintaining efficient flight configurations. The system design is presented, and a 6 DOF geometric control that is robust to singularities. Flight experiments further demonstrate and verify its capabilities.Comment: 10 pages, 6 figures, ISER 2018 conference submissio

Why Wouldn’t You Tell? Telling donor-conceived children about their conception

Research studies show that while an increasing number of parents of children conceived as a result of donor conception procedures appear to be telling - or planning to tell - their child about their conception (see Golombok et al., 2004; Brewaeys et al., 2005 for an overview), a large proportion of parents choose not to do so. Since the overwhelming majority of parents normally support truth-telling within their families, the decision to conceal the nature of the child’s conception - and deception to maintain its concealment - requires explanation

Pose-Following with Dual Quaternions

This work focuses on pose-following, a variant of path-following in which the goal is to steer the system's position and attitude along a path with a moving frame attached to it. Full body motion control, while accounting for the additional freedom to self-regulate the progress along the path, is an appealing trade-off. Towards this end, we extend the well-established dual quaternion-based pose-tracking method into a pose-following control law. Specifically, we derive the equations of motion for the full pose error between the geometric reference and the rigid body in the form of a dual quaternion and dual twist. Subsequently, we formulate an almost globally asymptotically stable control law. The global attractivity of the presented approach is validated in a spatial example, while its benefits over pose-tracking are showcased through a planar case-study.Comment: This paper has been accepted for publication at the IEEE Conference on Decision and Control (CDC), 2023. Copyright @ IEE

Fermentative Gewinnung von Paramylon aus Euglena gracilis auf Nebenprodukten der Stärkeindustrie in einer Pilotanlage

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