Keep Rollin' - Whole-Body Motion Control and Planning for Wheeled Quadrupedal Robots

We show dynamic locomotion strategies for wheeled quadrupedal robots, which combine the advantages of both walking and driving. The developed optimization framework tightly integrates the additional degrees of freedom introduced by the wheels. Our approach relies on a zero-moment point based motion optimization which continuously updates reference trajectories. The reference motions are tracked by a hierarchical whole-body controller which computes optimal generalized accelerations and contact forces by solving a sequence of prioritized tasks including the nonholonomic rolling constraints. Our approach has been tested on ANYmal, a quadrupedal robot that is fully torque-controlled including the non-steerable wheels attached to its legs. We conducted experiments on flat and inclined terrains as well as over steps, whereby we show that integrating the wheels into the motion control and planning framework results in intuitive motion trajectories, which enable more robust and dynamic locomotion compared to other wheeled-legged robots. Moreover, with a speed of 4 m/s and a reduction of the cost of transport by 83 % we prove the superiority of wheeled-legged robots compared to their legged counterparts.Comment: IEEE Robotics and Automation Letter

Unternehmenserbrecht – unde venis? Ein historischer Rückblick anlässlich der aktuellen Erbrechtsrevision

Im Rahmen der aktuellen Erbrechtsrevision wird im Schweizerischen Parlament die Einführung eines gesetzlichen Integralzuweisungsanspruchs zur Erhaltung von Unternehmen im Erbgang debattiert. Schon vor über 100 Jahren hatte sich EUGEN HUBER selbst an der Einführung eines solchen allgemeinen Unternehmenserbrechts versucht – und scheiterte knapp. Der historische Rückblick zeigt, dass sich schon damals dieselben Fragen stellten wie heute. Insbesondere die Frage, wie die Integralzuweisung von Unternehmen ermöglicht werden soll, ohne dabei zu stark in die Stellung der übrigen Erben einzugreifen, spaltete auch damals die Gemüter. Die historische Nachzeichnung der Debatte zeigt zum einen spannende Parallelen und Gegensätze zu den heutigen Streitpunkten in den Revisionsbemühungen auf. Zum anderen wird ein besonderes Augenmerk auf ein Rechtsinstitut gerichtet, das EUGEN HUBER damals als Kernstück seines Unternehmenserbrechts im Blick hatte: Die Gemeinderschaft (Art. 336-348 ZGB). Ob sie auch heute noch als Inspirationsquelle, Alternative oder Ergänzung dienen kann, dürfte nicht zuletzt vom Ausgang der Unternehmenserbrechtsrevision abhängen.Im Rahmen der aktuellen Erbrechtsrevision wird im Schweizerischen Parlament die Einführung eines gesetzlichen Integralzuweisungsanspruchs zur Erhaltung von Unternehmen im Erbgang debattiert. Schon vor über 100 Jahren hatte sich EUGEN HUBER selbst an der Einführung eines solchen allgemeinen Unternehmenserbrechts versucht – und scheiterte knapp. Der historische Rückblick zeigt, dass sich schon damals dieselben Fragen stellten wie heute. Insbesondere die Frage, wie die Integralzuweisung von Unternehmen ermöglicht werden soll, ohne dabei zu stark in die Stellung der übrigen Erben einzugreifen, spaltete auch damals die Gemüter. Die historische Nachzeichnung der Debatte zeigt zum einen spannende Parallelen und Gegensätze zu den heutigen Streitpunkten in den Revisionsbemühungen auf. Zum anderen wird ein besonderes Augenmerk auf ein Rechtsinstitut gerichtet, das EUGEN HUBER damals als Kernstück seines Unternehmenserbrechts im Blick hatte: Die Gemeinderschaft (Art. 336-348 ZGB). Ob sie auch heute noch als Inspirationsquelle, Alternative oder Ergänzung dienen kann, dürfte nicht zuletzt vom Ausgang der Unternehmenserbrechtsrevision abhängen

Involucrin mRNA Is More Abundant in Human Hair Follicles Than in Normal Epidermis

Involucrin is a precursor protein of the cornified cell envelope in epidermal keratinocytes, where it has been located by immunohistochemistry in the upper spinous and granular layers of human epidermis. In the hair follicle, involucrin has been found in the inner root sheath and in the upper layers of the infundibulum and the isthmus (upper outer root sheath), whereas its presence in the lower outer root sheath and the cortex has been controversial. Therefore, we analyzed the distribution of involucrin mRNA in adult scalp by Northern blotting and in situ hybridization. Northern blots showed more abundant involucrin mRNA in the follicular fraction than in the epidermal fraction of dissected scalp. In situ hybridization matched the immunohistologic results; transcripts of involucrin were expressed not only in the infundibulum and isthmus, but also in the hair cortex and medulla, in all layers of the inner root sheath, and in the inner cells of the lower outer root sheath (all of which lack a cell envelope at the ultrastructural level). However, involucrin was absent in the hair cuticle, which is the only compartment of the follicle possessing a morphologically distinct cell envelope. Our results suggest, first, that involucrin does not serve as a precursor protein of the cornified cell envelope in adult hair follicles, and second, that it is perhaps not necessary for the formation of the cell envelope in keratinocytes of the hair cuticle, as we did not find this precursor protein with highly sensitive methodology

Quasi-Normal Cornified Cell Envelopes in Loricrin Knockout Mice Imply the Existence of a Loricrin Backup System

The cornified cell envelope, a lipoprotein layer that assembles at the surface of terminally differentiated keratinocytes, is a resilient structure on account of covalent crosslinking of its constituent proteins, principally loricrin, which accounts for up to 60%-80% of total protein. Despite the importance of the cell envelope as a protective barrier, knocking out the loricrin gene in mice results in only mild syndromes. We have investigated the epidermis and forestomach epithelium of these mice by electron microscopy. In both tissues, corneocytes have normal-looking cell envelopes, despite the absence of loricrin, which was confirmed by immunolabeling, and the absence of the distinctive loricrin-containing keratohyalin granules (L-granules). Isolated cell envelopes were normal in thickness (≈15 nm) and mass per unit area (≈7.3 kDa per nm2); however, metal shadowing revealed an altered substructure on their cytoplasmic surface. Their amino acid compositions indicate altered protein compositions. Analysis of these data implies that the epidermal cell envelopes have elevated levels of the small proline-rich proteins, and cell envelopes of both kinds contain other protein(s) that, like loricrin, are rich in glycine and serine. These observations imply that, in the absence of loricrin, the mechanisms that govern cell envelope assembly function normally but employ different building-blocks

Characterisation of Candida parapsilosis infection of an in vitro reconstituted human oral epithelium

Oral candidosis is a common problem in immunocompromised patients, and whilst Candida albicans is regarded as the principal cause of infection, other non-Candida albicans Candida (NCAC) species are increasingly being recognized as human pathogens. Relatively little is known about the virulence factors associated with NCAC species, and the aim of this study was to use a reconstituted human oral epithelium (RHOE) to examine epithelial infection with Candida parapsilosis. Strains originating from the oral and vaginal mucosa and from the urinary tract were all shown to colonize RHOE in a strain-dependent manner. Strain differences were found in the colonizing morphology and in the extent of invasion of the RHOE. Low invasion of RHOE was detected for strains after 12 h, whereas extensive tissue damage was evident after 24 h when assessed using histological examination and lactate dehydrogenase activity determination. Tissue damage was reduced in the presence of pepstatin A, although C. parapsilosis invasion of the tissue was not inhibited. Realtime polymerase chain reaction of secreted aspartyl proteinase (SAP) genes (SAPP1– 3) showed that expression was strain dependent, with an increased expression generally occurring for Candida infecting RHOE compared with planktonic equivalents. In summary, C. parapsilosis was not highly invasive of RHOE but did induce significant tissue damage, which could relate to specific SAP gene expression.Fundação para a Ciência e Tecnologia (FCT) - SFRH/BD/28341/2006 e o projecto PDTC/ BIO/61112/200

Cardiogenesis with a focus on vasculogenesis and angiogenesis

The initial intraembryonic vasculogenesis occurs in the cardiogenic mesoderm. Here, a cell population of proendocardial cells detaches from the mesoderm that subsequently generates the single endocardial tube by forming vascular plexuses. In the course of embryogenesis, the endocardium retains vasculogenic, angiogenic and haematopoietic potential. The coronary blood vessels that sustain the rapidly expanding myocardium develop in the course of the formation of the cardiac loop by vasculogenesis and angiogenesis from progenitor cells of the proepicardial serosa at the venous pole of the heart as well as from the endocardium and endothelial cells of the sinus venosus. Prospective coronary endothelial cells and progenitor cells of the coronary blood vessel walls (smooth muscle cells, perivascular cells) originate from different cell populations that are in close spatial as well as regulatory connection with each other. Vasculo‐ and angiogenesis of the coronary blood vessels are for a large part regulated by the epicardium and epicardium‐derived cells. Vasculogenic and angiogenic signalling pathways include the vascular endothelial growth factors, the angiopoietins and the fibroblast growth factors and their receptors

Cardiovascular development: towards biomedical applicability: Epicardium-derived cells in cardiogenesis and cardiac regeneration

During cardiogenesis, the epicardium grows from the proepicardial organ to form the outermost layer of the early heart. Part of the epicardium undergoes epithelial-mesenchymal transformation, and migrates into the myocardium. These epicardium- derived cells differentiate into interstitial fibroblasts, coronary smooth muscle cells, and perivascular fibroblasts. Moreover, epicardium-derived cells are important regulators of formation of the compact myocardium, the coronary vasculature, and the Purkinje fiber network, thus being essential for proper cardiac development. The fibrous structures of the heart such as the fibrous heart skeleton and the semilunar and atrioventricular valves also depend on a contribution of these cells during development. We hypothesise that the essential properties of epicardium-derived cells can be recapitulated in adult diseased myocardium. These cells can therefore be considered as a novel source of adult stem cells useful in clinical cardiac regeneration therapy