Investigation of the resilience of cyclically actuated pine cone scales ofPinus jeffreyi.

The resilience of pine cone scales has been investigated in the context of current architectural efforts to develop bioinspired passive façade shading systems that can help regulate the indoor climate. As previously shown for other species, separated tissues ofPinus jeffreyipine cone scales show independent hygroscopic bending. The blocking force that pine cone scales can generate during a closing movement is shown to be affected by the length, width and mass of the scales. After cyclically actuating pine cone scales by submerging and drying them for 102 cycles and comparing their functional characteristics measured in the undamaged and damaged state, they were still able to achieve 97% of their undamaged blocking force and torque and over 94% of their undamaged opening angle. Despite evidence of cracking within the sclereid cell layer and extensive delamination of sclerenchyma fibres, no loss of function was observed in any tested pine cone scale. This functional resilience and robustness may allowP. jeffreyitrees to continue seed dispersal for longer periods of time and to reliably protect seeds that have not yet been released. These results have contributed to a better understanding of the pine cone scale and may provide inspiration for further improving the long-term performance of passive, hygro-sensitive façade shading systems.

A Biohybrid Self-Dispersing Miniature Machine Using Wild Oat Fruit Awns for Reforestation and Precision Agriculture.

Advances in bioinspired and biohybrid robotics are enabling the creation of multifunctional systems able to explore complex unstructured environments. Inspired by Avena fruits, a biohybrid miniaturized autonomous machine (HybriBot) composed of a biomimetic biodegradable capsule as cargo delivery system and natural humidity-driven sister awns as biological motors is reported. Microcomputed tomography, molding via two-photon polymerization and casting of natural awns into biodegradable materials is employed to fabricate multiple HybriBots capable of exploring various soil and navigating soil irregularities, such as holes and cracks. These machines replicate the dispersal movements and biomechanical performances of natural fruits, achieving comparable capsule drag forces up to ≈0.38 N and awns torque up to ≈100 mN mm-1. They are functionalized with fertilizer and are successfully utilized to germinate selected diaspores. HybriBots function as self-dispersed systems with applications in reforestation and precision agriculture.

Leaf unfolding and lamina biomechanics inSyngonium podophyllumandPilea peperomioides.

In nature, leaves and their laminae vary in shape, appearance and unfolding behaviour. We investigated peltate leaves of two model species with peltate leaves and highly different morphology (Syngonium podophyllumandPilea peperomioides) and two distinct unfolding patterns via time-lapse recordings: we observed successive unfolding of leaf halves inS. podophyllumand simultaneous unfolding inP. peperomioides.Furthermore, we gathered relevant morphological and biomechanical data in juvenile (unfolding) and adult (fully unfolded) leaves of both species by measuring the thickness and the tensile modulus of both lamina and veins as a measure of their stiffness. InS. podophyllum, lamina and veins stiffen after unfolding, which may facilitate unfolding in the less stiff juvenile lamina. Secondary venation highly contributes to stiffness in the adult lamina ofS. podophyllum, while the lamina itself withstands tensile loads best in direction parallel to secondary veins. In contrast, the leaf ofP. peperomioideshas a higher lamina thickness and small, non-prominent venation and is equally stiff in every region and direction, although, as is the case inS. podophyllum, thickness and stiffness increase during ontogeny of leaves from juvenile to adult. It could be shown that (changes in) lamina thickness and stiffness can be well correlated with the unfolding processes of both model plants, so that we conclude that functional lamina morphology in juvenile and adult leaf stages and the ontogenetic transition while unfolding is highly dependent on biomechanical characteristics, though other factors are also taken into consideration and discussed.

Analysis of the peel structure of different Citrus spp. via light microscopy, SEM and µCT with manual and automatic segmentation.

The peels of lime, lemon, pomelo and citron are investigated at macroscopic and microscopic level. The structural composition of the peels is compared and properties such as peel thickness, proportion of flavedo, density and proportion of intercellular spaces are determined. µCT images are used to visualize vascular bundles and oil glands. SEM images provide information about the appearance of the cellular tissue in the outer flavedo and inner albedo. The proportion of intercellular spaces is quantitatively determined by manual and software-assisted analysis (ilastik). While there are macroscopic differences in the fruits, they differ only slightly in the orientation of the vascular bundles and the arrangement of the oil glands. However, in peel thickness and flavedo thickness, the fruit peels differ significantly from each other. There are no significant differences between the two analysis methods used, although the use of ilastik is preferred due to time reduction of up to 70%. The large amount of intercellular spaces in the albedo but also the denser flavedo both have a mechanical protective function to prevent damage to the fruit. In addition, the entire peel structure is mechanically reinforced by vascular bundles. This combination of penetration protection (flavedo) and energy dissipation (albedo) makes Citrus spp. peels a promising inspiration for technical material systems.

Is a Forest Fire a Natural Disaster? Investigating the Fire Tolerance of Various Tree Species-An Educational Module.

Wildfires are unplanned conflagrations perceived as a threat by humans. However, fires are essential for the survival of fire-adapted plants. On the one hand, wildfires cause major damage worldwide, burning large areas of forests and landscapes, threatening towns and villages, and generating high levels of air pollution. On the other hand, fire-adapted plants (pyrophytes) in the fire landscapes of the Earth are able to survive exposure to heat (e.g., because of their thick bark, which protects their living tissue) and benefit from fire directly (e.g., fire initiates cone opening and seed release) or indirectly (e.g., fewer competing plants of fire-sensitive species remain, seeds germinate in the ash-fertilized soil). We present the experimental set-up and results of a fire experiment on bark samples used as a basis to assess the fire tolerance of various trees. Fire tolerance is defined as the ability of a tree to survive a surface fire (up to 200 °C and 5 min duration). The measure of the fire tolerance for a tree species is the time taken for the vascular cambium under the insulating bark to reach the critical temperature of 60 °C. Within an educational module, we provide worksheets for teachers and students enabling them to analyze the fire tolerance of various tree barks.

Toward a structural identification of metastable molecular conformations.

Interpreting high-dimensional data from molecular dynamics simulations is a persistent challenge. In this paper, we show that for a small peptide, deca-alanine, metastable states can be identified through a neural net based on structural information alone. While processing molecular dynamics data, dimensionality reduction is a necessary step that projects high-dimensional data onto a low-dimensional representation that, ideally, captures the conformational changes in the underlying data. Conventional methods make use of the temporal information contained in trajectories generated through integrating the equations of motion, which forgoes more efficient sampling schemes. We demonstrate that EncoderMap, an autoencoder architecture with an additional distance metric, can find a suitable low-dimensional representation to identify long-lived molecular conformations using exclusively structural information. For deca-alanine, which exhibits several helix-forming pathways, we show that this approach allows us to combine simulations with different biasing forces and yields representations comparable in quality to other established methods. Our results contribute to computational strategies for the rapid automatic exploration of the configuration space of peptides and proteins.

Force Generation in the Coiling Tendrils of Passiflora caerulea.

Tendrils of climbing plants coil along their length, thus forming a striking helical spring and generating tensional forces. It is found that, for tendrils of the passion flower Passiflora caerulea, the generated force lies in the range of 6-140 mN, which is sufficient to lash the plant tightly to its substrate. Further, it is revealed that the generated force strongly correlates with the water status of the plant. Based on a combination of in situ force measurements with anatomical investigations and dehydration-rehydration experiments on both entire tendril segments and isolated lignified tissues, a two-phasic mechanism for spring formation is proposed. First, during the free coiling phase, the center of the tendril begins to lignify unilaterally. At this stage, both the generated tension and the stability of the form of the spring still depend on turgor pressure. The unilateral contraction of a bilayer as being the possible driving force for the tendril coiling motion is discussed. Second, in a stabilization phase, the entire center of the coiled tendril lignifies, stiffening the spring and securing its function irrespective of its hydration status.

Glaucoma-Associated CDR1 Peptide Promotes RGC Survival in Retinal Explants through Molecular Interaction with Acidic Leucine Rich Nuclear Phosphoprotein 32A (ANP32A).

Glaucoma is a complex, multifactorial optic neuropathy mainly characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons, resulting in a decline of visual function. The pathogenic molecular mechanism of glaucoma is still not well understood, and therapeutic strategies specifically addressing the neurodegenerative component of this ocular disease are urgently needed. Novel immunotherapeutics might overcome this problem by targeting specific molecular structures in the retina and providing direct neuroprotection via different modes of action. Within the scope of this research, the present study showed for the first time beneficial effects of the synthetic CDR1 peptide SCTGTSSDVGGYNYVSWYQ on the viability of RGCs ex vivo in a concentration-dependent manner compared to untreated control explants (CTRL, 50 µg/mL: p < 0.05 and 100 µg/mL: p < 0.001). Thereby, this specific peptide was identified first as a potential biomarker candidate in the serum of glaucoma patients and was significantly lower expressed in systemic IgG molecules compared to healthy control subjects. Furthermore, MS-based co-immunoprecipitation experiments confirmed the specific interaction of synthetic CDR1 with retinal acidic leucine-rich nuclear phosphoprotein 32A (ANP32A; p < 0.001 and log2 fold change > 3), which is a highly expressed protein in neurological tissues with multifactorial biological functions. In silico binding prediction analysis revealed the N-terminal leucine-rich repeat (LRR) domain of ANP32A as a significant binding site for synthetic CDR1, which was previously reported as an important docking site for protein-protein interactions (PPI). In accordance with these findings, quantitative proteomic analysis of the retinae ± CDR1 treatment resulted in the identification of 25 protein markers, which were significantly differentially distributed between both experimental groups (CTRL and CDR1, p < 0.05). Particularly, acetyl-CoA biosynthesis I-related enzymes (e.g., DLAT and PDHA1), as well as cytoskeleton-regulating proteins (e.g., MSN), were highly expressed by synthetic CDR1 treatment in the retina; on the contrary, direct ANP32A-interacting proteins (e.g., NME1 and PPP2R4), as well as neurodegenerative-related markers (e.g., CEND1), were identified with significant lower abundancy in the CDR1-treated retinae compared to CTRL. Furthermore, retinal protein phosphorylation and histone acetylation were also affected by synthetic CDR1, which are both partially controlled by ANP32A. In conclusion, the synthetic CDR1 peptide provides a great translational potential for the treatment of glaucoma in the future by eliciting its neuroprotective mechanism via specific interaction with ANP32A's N terminal LRR domain.

Biomimetics in Botanical Gardens-Educational Trails and Guided Tours.

The first botanical gardens in Europe were established for the study of medicinal, poisonous, and herbal plants by students of medicine or pharmacy at universities. As the natural sciences became increasingly important in the 19th Century, botanical gardens additionally took on the role of public educational institutions. Since then, learning from living nature with the aim of developing technical applications, namely biomimetics, has played a special role in botanical gardens. Sir Joseph Paxton designed rainwater drainage channels in the roof of the Crystal Palace for the London World's Fair in 1881, having been inspired by the South American giant water lily (Victoria amazonica). The development of the Lotus-Effect® at the Botanical Garden Bonn was inspired by the self-cleaning leaf surfaces of the sacred lotus (Nelumbo nucifera). At the Botanic Garden Freiburg, a self-sealing foam coating for pneumatic systems was developed based on the self-sealing of the liana stems of the genus Aristolochia. Currently, botanical gardens are both research institutions and places of lifelong learning. Numerous botanical gardens provide biomimetics trails with information panels at each station for self-study and guided biomimetics tours with simple experiments to demonstrate the functional principles transferred from the biological model to the technical application. We present eight information panels suitable for setting up education about biomimetics and simple experiments to support guided garden tours about biomimetics.

Advances in Biomimetics: Combination of Various Effects at Different Scales.

Biomimetics (bionics, bioinspired technology) refers to research on living systems and attempts to transfer their properties to engineering applications [...].

Cross-Sectional 4D-Printing: Upscaling Self-Shaping Structures with Differentiated Material Properties Inspired by the Large-Flowered Butterwort (Pinguicula grandiflora).

Extrusion-based 4D-printing, which is an emerging field within additive manufacturing, has enabled the technical transfer of bioinspired self-shaping mechanisms by emulating the functional morphology of motile plant structures (e.g., leaves, petals, capsules). However, restricted by the layer-by-layer extrusion process, much of the resulting works are simplified abstractions of the pinecone scale's bilayer structure. This paper presents a new method of 4D-printing by rotating the printed axis of the bilayers, which enables the design and fabrication of self-shaping monomaterial systems in cross sections. This research introduces a computational workflow for programming, simulating, and 4D-printing differentiated cross sections with multilayered mechanical properties. Taking inspiration from the large-flowered butterwort (Pinguicula grandiflora), which shows the formation of depressions on its trap leaves upon contact with prey, we investigate the depression formation of bioinspired 4D-printed test structures by varying each depth layer. Cross-sectional 4D-printing expands the design space of bioinspired bilayer mechanisms beyond the XY plane, allows more control in tuning their self-shaping properties, and paves the way toward large-scale 4D-printed structures with high-resolution programmability.

[Why outpatient surgery does not work in hospitals - or medical practices - as yet]. / Ambulantes Operieren: Warum es im Krankenhaus (noch) nicht klappt ­ und in der Praxis auch nicht.

High costs in the German health care system and a lack of nursing staff make a shift from inpatient to outpatient treatment unavoidable. The new catalogue announced for outpatient surgical procedures will contain up to 50% of all procedures in urology. In anticipation of these major changes, neither hospitals nor medical practices are able to prepare adequately since the precise catalogue, the infrastructural changes required, and the rules of remuneration have not yet been clarified. Without some degree of certainty for planning, nobody will be able or willing to invest into future structures.

Exploiting compositional disorder in collectives of light-driven circle walkers.

Emergent behavior in collectives of "robotic" units with limited capabilities that is robust and programmable is a promising route to perform tasks on the micro and nanoscale that are otherwise difficult to realize. However, a comprehensive theoretical understanding of the physical principles, in particular steric interactions in crowded environments, is still largely missing. Here, we study simple light-driven walkers propelled through internal vibrations. We demonstrate that their dynamics is well captured by the model of active Brownian particles, albeit with an angular speed that differs between individual units. Transferring to a numerical model, we show that this polydispersity of angular speeds gives rise to specific collective behavior: self-sorting under confinement and enhancement of translational diffusion. Our results show that, while naively perceived as imperfection, disorder of individual properties can provide another route to realize programmable active matter.

Artificial Tendrils Mimicking Plant Movements by Mismatching Modulus and Strain in Core and Shell.

Motile organs have evolved in climbing plants enabling them to find a support and, after secure attachment, to reach for sunlight without investing in a self-supporting stem. Searching movements, the twining of stems, and the coiling of tendrils are involved in successful plant attachment. Such coiling movements have great potential in robotic applications, especially if they are reversible. Here, the underlying mechanism of tendril movement based on contractile fibers is reported, as illustrated by a function-morphological analysis of tendrils in several liana species and the encoding of such a principle in a core-shell multimaterial fiber (MMF) system. MMFs are composed of a shape-memory core fiber (SMCF) and an elastic shell. The shape-memory effect of the core fibers enables the implementation of strain mismatch in the MMF by physical means and provides thermally controlled reversible motion. The produced MMFs show coiling and/or uncoiling behavior, with a high reversible actuation magnitude of ≈400%, which is almost 20 times higher compared with similar stimuli for sensitive soft actuators. The movements in these MMFs rely on the crystallization/melting behavior of oriented macromolecules of SMCF.

[Structure of outpatient urology care in Germany]. / Versorgungsstruktur der ambulanten Urologie in Deutschland.

BACKGROUND: Although urological specialist practices are central pillars of outpatient care, there is a lack of current data on the care structure of these practices. A description of the structures in large cities versus rural areas as well as gender effects and generational differences is needed not only as a baseline measure for further studies. MATERIALS AND METHODS: The survey includes data from the physician directory of the Stiftung Gesundheit as well as from the German Medical Association and the Federal Statistical Office. Colleagues were divided into subgroups. Based on the different subgroup sizes, statements about the care structure of outpatient urology in Germany can be made. RESULTS: While the majority of urologists in larger cities work in professional practice groups and care for fewer patients on average, in rural areas there is a particularly high proportion of individual practices with more inhabitants to be cared for per urologist. Female urologists work more frequently in the context of inpatient care. When female urology specialists choose to establish themselves, they are more likely to do so in practice groups and in urban areas. In addition, there is a shift in gender distribution: the younger the age subgroup considered, the higher the proportion of female urologists among all colleagues. CONCLUSIONS: This study is the first to describe the current structure of outpatient urology care in Germany. Future trends are already emerging that will significantly influence our way of working and the care of patients in the coming years.

Conjoining Trees for the Provision of Living Architecture in Future Cities: A Long-Term Inosculation Study.

Faced with the environmental challenges posed by climate change, architects are creating nature-based solutions for urban areas, such as transforming living trees into artificial architectural structures. In this study, we have analyzed stem pairs of five tree species conjoined for more than eight years by measuring the stem diameters below and above the resulting inosculation and by calculating the respective diameter ratio. Our statistical analyses reveal that Platanus × hispanica and Salix alba stems do not differ significantly in diameter below inosculation. However, in contrast to P. × hispanica, the diameters of the conjoined stems above inosculation differ significantly in S. alba. We provide a binary decision tree based on diameter comparisons above and below inosculation as a straightforward tool for identifying the likelihood of full inosculation with water exchange. Moreover, we have compared branch junctions and inosculations by means of anatomical analyses, micro-computed tomography, and 3D reconstructions showing similarities in the formation of common annual rings that increase the capacity for water exchange. Due to the highly irregular cell arrangement in the center of the inosculations, cells cannot be assigned clearly to either of the stems. In contrast, cells in the center of branch junctions can always be attributed to one of the branches.

Inverse condensation of adsorbed molecules with two conformations.

Conventional gas-liquid phase transitions feature a coexistence line that has a monotonic and positive slope in line with our intuition that cooling always leads to condensation. Here, we study the inverse phenomenon, condensation of adsorbed organic molecules into dense domains upon heating. Our considerations are motivated by recent experiments [Aeschlimann et al., Angew. Chem., Int. Ed. 60, 19117-19122 (2021)], which demonstrate the partial dissolution of an ordered molecular monolayer and the mobilization of molecules upon cooling. We introduce a simple lattice model in which each site can have three states corresponding to unoccupied and two discernible molecular conformations. We investigate this model through Monte Carlo simulations, mean-field theory, and exact results based on the analytical solution of the Ising model in two dimensions. Our results should be broadly applicable to molecules with distinct conformations that have sufficiently different entropies or heat capacities.

Improvement of a microfiber filter for domestic washing machines.

The development of enhanced processes for filtration is one solution for stopping the increasing freshwater and sea pollution caused by microplastic and microfibers. Major contributors to micro-X pollution are domestic devices such as washing machines, which also hold a high technical potential for separating problematic soils from waste water during cleaning cycles. The focus of the present paper are the biomimetic development of a novel concept for filtration and removal of particles such as microfibers in conventional washing machines. To this goal, a TRIZ analysis yielded viable solutions for the major key issues. In a next step, measurements were made with various filters with and without ribbed structures. The results are promising for the incorporation in a filter concept that is easy to operate and cost-effective.