Multiple Appendages Research Articles

Programmable Artificial Skins Accomplish Antiscar Healing with Multiple Appendage Regeneration.

Functional appendage regeneration is essential for skin rehabilitation, but it has always failed by current existing healing approaches, owing to their inefficacy in preventing disfiguring scars. In this study, a novel regeneration-directing artificial skin (RDAS) system is presented, which is based on the rational design of multi-layered hydrogels that closely mimic natural skin matrices. By leveraging the programmability and architectural rigidity of DNA components, without the need for exogenous cell transplantation, such RDAS effectively minimizes tissue fibrosis by accurately guiding the regenerative process in wound fibroblasts, enabling rapid scarless wound repair, restoration of dermal function, and successful in situ regeneration of multiple appendages, such as hair follicles (HFs), sebaceous glands (SGs), and sweat glands (SwGs). Therefore, the RDAS offers a cell-free antiscarring therapeutic strategy for regenerative wound healing, resulting in improved outcomes. This innovative approach holds great potential for future clinical applications and burn rehabilitation.

Impact of Crustacean Morphology on Metachronal Propulsion: A Numerical Study

Metachrony is defined as coordinated asynchronous movement throughout multiple appendages, such as the cilia of cells and swimmerets of crustaceans. Used by species of crustaceans and microscopic cells to move through fluid, the process of metachronal propulsion was investigated. A rigid crustacean model with paddles moving in symmetric strokes was created to simulate metachronal movement. Coupled with the surrounding fluid domain, the immersed boundary method was employed to analyze the fluid–structure interactions. To explore the effect of a nonlinear morphology on the efficiency of metachronal propulsion, a range of crustacean body shapes was generated and simulated, from upward curves to downward curves. The highest propulsion velocity was found to be achieved when the crustacean model morphology was a downward curve, specifically a parabola of leading coefficient k = −0.4. This curved morphology resulted in a 4.5% higher velocity when compared to the linear model. As k deviated from −0.4, the propulsion velocity decreased with increasing magnitude, forming a concave downward trend. The impact of body shape on propulsion velocity is shown by how the optimal velocity with k = −0.4 is 71.5% larger than the velocity at k = 1. Overall, this study suggests that morphology has a significant impact on metachronal propulsion.

Omnidirectional propulsion in a metachronal swimmer.

Aquatic organisms often employ maneuverable and agile swimming behavior to escape from predators, find prey, or navigate through complex environments. Many of these organisms use metachronally coordinated appendages to execute complex maneuvers. However, though metachrony is used across body sizes ranging from microns to tens of centimeters, it is understudied compared to the swimming of fish, cetaceans, and other groups. In particular, metachronal coordination and control of multiple appendages for three-dimensional maneuvering is not fully understood. To explore the maneuvering capabilities of metachronal swimming, we combine 3D high-speed videography of freely swimming ctenophores (Bolinopsis vitrea) with reduced-order mathematical modeling. Experimental results show that ctenophores can quickly reorient, and perform tight turns while maintaining forward swimming speeds close to 70% of their observed maximum-performance comparable to or exceeding that of many vertebrates with more complex locomotor systems. We use a reduced-order model to investigate turning performance across a range of beat frequencies and appendage control strategies, and reveal that ctenophores are capable of near-omnidirectional turning. Based on both recorded and modeled swimming trajectories, we conclude that the ctenophore body plan enables a high degree of maneuverability and agility, and may be a useful starting point for future bioinspired aquatic vehicles.

Writing with Multiple Appendages

Four pairs of images from the Postcards from the Underground (2022) print series are presented here as experiments in translating invertebrate underground worlds. Artist Perdita Phillips and cultural theorist Astrida Neimanis collaborated to create an interdisciplinary ‘walkshop’ event to the coal mining town of Lithgow, as part of Phillips’ Artsource both/and artist in residence at Artspace, Sydney in 2017. The many forms of stygofauna—small invertebrate animals including worms, mites, snails, insects and many crustacea—can be found in the millimetreswide in-between spaces in groundwater. Short-range endemism is common—due to their distribution in isolated patches beneath semi-arid to rainforest landscapes in Australia—and sporadic relic distribution world-wide. Working between Neimanis’ text and Phillips’ drawings and found images, the conversations with and through stygofauna, underground water and mining were then developed into colour postcards, that use a red/cyan optical masking technique. The images can be decoded with a red filter that is held up to the eye. The previously invisible cyan delineations are then revealed from beneath—alluding to the layers of concern and the double state of both/and—“caught up in both the noticing and notnoticing of each other” that the artist/author were articulating (Neimanis and Phillips 137). The swirling patterns of swimming and the complex fingering of many limbs were rendered into cryptic scores. The postcards explore notions of hiding/revealing and comprehension and miscomprehension of subterranean ecosystems, through the multiple scratchings of the skittering limbs of stygofauna.
 Phillips, Perdita and Astrida Neimanis. Postcards from the Underground. 2022. Private Collection.

Cocoons, Fungi, Nematodes, Rhizoids, Annelids, Eggs, Arthropoda in Gale Crater, Mars?

White and dark gray oblong-ovoid cocoon-egg-like forms (“cocoon-eggs”), less than a mm in diameter, many with a single hole in one end, and some with unidentifiable specimens protruding from (exiting or entering) these holes, were photographed on mudstone in Gale Crater, Mars, on Sol 1302. If biological some of these cocoon-eggs may be frozen, fossilized or have already “hatched” or undergone metamorphosis. Specimens resembling segmented and tubular worms and rhizoids and those with multiple appendages (Arthropoda) were also photographed on these and other substrates on Mars, including on Sols 130, 132, 302, 551, 553, 808, 809, 868, 906, 1280, 1921, in Gale Crater. Many Sol 1302 “cocoon-eggs” are embedded in substrate that appears to consist entirely of a coral-stromatolite-like mass of worm- and larvae-like forms; and similar worm and segmented larvae forms appear in the interior of three semi-transparent ovoid structures. Embedded in the soil surrounding these “cocoon-eggs” are numerous concave patches reminiscent of dried “egg-yolk,” cocoon remnants or fungus, and that may represent the final stage of “cocoon” collapse and disintegration; or they are fungal in origin. Some of the segmented and tubular worm-like forms may include rhizoids and tubular fungi. Ovoids with open apertures may be evidence of fungal sporing. The possibility that fungus and diverse species and their “cocoons” share the same substrate is supported by what appears to be cyanobacteria, worms, insecta (arthropoda), and stalks topped by ovoids or ovoid-shaped microbialite-like sediment. Fungi, lichens, cyanobacteria, stromatolites and arthropoda have been previously reported in other areas of Gale Crater, whereas fungal “puffballs” and specimens attached to rocks with stalks and topped with mushroom-like caps have been observed in Meridiani Planum. The possibility these specimens are abiogenic cannot be ruled out. The evidence, in our view, arguably supports the hypotheses that various organisms colonized Mars in the ancient or recent past.

Spatiotemporal Asymmetry in Metachronal Rowing at Intermediate Reynolds Numbers.

In drag-based swimming, individual propulsors operating at low Reynolds numbers (where viscous forces dominate over inertial forces) must execute a spatially asymmetric stroke to produce net fluid displacement. Temporal asymmetry (that is, differing duration between the power vs. recovery stroke) does not affect the overall generated thrust in this time-reversible regime. Metachronal rowing, in which multiple appendages beat sequentially, is used by a wide variety of organisms from low to intermediate Reynolds numbers. At the upper end of this range, inertia becomes important, and increasing temporal asymmetry can be an effective way to increase thrust. However, the combined effects of spatial and temporal asymmetry are not fully understood in the context of metachronal rowing. To explore the role of spatiotemporal asymmetry in metachronal rowing, we combine laboratory experiments and reduced-order analytical modeling. We measure beat kinematics and generated flows in two species of lobate ctenophores across a range of body sizes, from 7 to 40 mm in length. We observe characteristically different flows in ctenophores of differing body size and Reynolds number, and a general decrease in spatial asymmetry and increase in temporal asymmetry with increasing Reynolds number. We also construct a one-dimensional mathematical model consisting of a row of oscillating flat plates whose flow-normal areas change with time, and use it to explore the propulsive forces generated across a range of Reynolds numbers and kinematic parameters. The model results show that while both types of asymmetry increase force production, they have different effects in different regions of the parameter space. These results may have strong biological implications, as temporal asymmetry can be actively controlled while spatial asymmetry is likely to be partially or entirely driven by passive fluid-structure interaction.

Metachronal Coordination of Multiple Appendages for Swimming and Pumping.

As a strategy for creating fluid flow, metachronal motion is widespread across sizes and species, including a broad array of morphologies, length scales, and coordination patterns. Because of this great diversity, it has not generally been viewed holistically: The study of metachrony for swimming and pumping has historically been taxonomically siloed, in spite of many commonalities between seemingly disparate organisms. The goal of the present symposium was to bring together individuals from different backgrounds, all of whom have made substantial individual contributions to our understanding of the fluid dynamics of metachronal motion. Because these problems share a common physical-mathematical basis, intentionally connecting this community is likely to yield future collaborations and significant scientific discovery. Here, we briefly introduce the concept of metachronal motion, present the benefits of creating a research network based on the common aspects of metachrony across biological systems, and outline the contributions to the symposium.

Energetics of synchronization for model flagella and cilia.

Synchronization is often observed in the swimming of flagellated cells, either for multiple appendages on the same organism or between the flagella of nearby cells. Beating cilia are also seen to synchronize their dynamics. In 1951, Taylor showed that the observed in-phase beating of the flagella of coswimming spermatozoa was consistent with minimization of the energy dissipated in the surrounding fluid. Here we revisit Taylor's hypothesis for three models of flagella and cilia: (1) Taylor's waving sheets with both longitudinal and transverse modes, as relevant for flexible flagella, (2) spheres orbiting above a no-slip surface to model interacting flexible cilia, and (3) whirling rods above a no-slip surface to address the interaction of nodal cilia. By calculating the flow fields explicitly, we show that the rate of working of the model flagella or cilia is minimized in our three models for (1) a phase difference depending on the separation of the sheets and precise waving kinematics, (2) in-phase or opposite-phase motion depending on the relative position and orientation of the spheres, and (3) in-phase whirling of the rods. These results will be useful in future models probing the dynamics of synchronization in these setups.

A RANS-BEM Method to Efficiently Include Appendage Effects in RANS-Based Hull Shape Evaluation

Abstract. In this paper an approach to mimic the influence of appendages on the pressure distribution on a boat’s hull in RANS simulations is given. While, of course, the appendages could be modelled explicitly in the RANS simulation, this significantly increases the cell count and CPU-time requirements of the simulations, particularly for boats with multiple appendages. In this approach it is assumed that the pressure fields generated by the appendages can be decomposed into two parts: one related to lift (asymmetric) and one related to the displaced volume (symmetric). For these parts actuator line momentum theory is utilized, and doublet mass sources are described based on potential flow theory. An initial assessment of the approach’s capabilities and accuracy is presented based on the SYRF wide light series (Claughton, 2015), showing good promise. An application example with particular focus on the reduction of CPU-time requirement is given based on a boat fitted with canting keel and DSS foil.

Using bioprinting and spheroid culture to create a skin model with sweat glands and hair follicles.

BackgroundSweat glands (SGs) and hair follicles (HFs) are two important cutaneous appendages that play crucial roles in homeostatic maintenance and thermoregulation, and their interaction is involved in wound healing. SGs can be regenerated from mesenchymal stem cell-laden 3D bioprinted scaffolds, based on our previous studies, whereas regeneration of HFs could not be achieved in the same model. Due to the lack of an in vitro model, the underlying molecular mechanism of the interaction between SGs and HFs in regeneration could not be fully understood. The purpose of the present study was to establish an in vitro model of skin constructs with SGs and HFs and explore the interaction between these two appendages in regeneration.MethodsTo investigate the interaction effects between SGs and HFs during their regeneration processes, a combined model was created by seeding HF spheroids on 3D printed SG scaffolds. The interaction between SG scaffolds and HF spheroids was detected using RNA expression and immunofluorescence staining. The effects of microenvironmental cues on SG and HF regeneration were analysed by altering seed cell types and plantar dermis homogenate in the scaffold.ResultsAccording to this model, we overcame the difficulties in simultaneously inducing SG and HF regeneration and explored the interaction effects between SG scaffolds and HF spheroids. Surprisingly, HF spheroids promoted both SG and HF differentiation in SG scaffolds, while SG scaffolds promoted SG differentiation but had little effect on HF potency in HF spheroids. Specifically, microenvironmental factors (plantar dermis homogenate) in SG scaffolds effectively promoted SG and HF genesis in HF spheroids, no matter what the seed cell type in SG scaffolds was, and the promotion effects were persistent.ConclusionsOur approach elucidated a new model for SG and HF formation in vitro and provided an applicable platform to investigate the interaction between SGs and HFs in vitro. This platform might facilitate 3D skin constructs with multiple appendages and unveil the spatiotemporal molecular program of multiple appendage regeneration.

Computed tomography sheds new light on the affinities of the enigmatic euarthropod Jianshania furcatus from the early Cambrian Chengjiang biota

BackgroundThe Chengjiang biota is one of the most species-rich Cambrian Konservat-Lagerstätten, and preserves a community dominated by non-biomineralized euarthropods. However, several Chengjiang euarthropods have an unfamiliar morphology, are extremely rare, or incompletely preserved.ResultsWe employed micro-computed tomography to restudy the enigmatic euarthropod Jianshania furcatus. We reveal new morphological details, and demonstrate that the specimens assigned to this species represent two different taxa. The holotype of J. furcatus features a head shield with paired anterolateral notches, stalked lateral eyes, and an articulated tailspine with a bifurcate termination. The other specimen is formally redescribed as Xiaocaris luoi gen. et sp. nov., and is characterized by stalked eyes connected to an anterior sclerite, a subtrapezoidal head shield covering three small segments with reduced tergites, a trunk with 15 overlapping tergites with a well-developed dorsal keel, and paired tail flukes.ConclusionsThe presence of antennae, biramous appendages with endopods composed of 15 articles, and multiple appendage pairs associated with the trunk tergites identify X. luoi nov. as a representative of Fuxianhuiida, an early branching group of stem-group euarthropods endemic to the early Cambrian of Southwest China. X. luoi nov. represents the fifth fuxianhuiid species described from the Chengjiang biota, and its functional morphology illuminates the ecological diversity of this important clade for understanding the early evolutionary history of euarthropods.

On hydrodynamic behavior of fluid resonance in moonpool and its suppression by using various convex appendages

Fluid resonance in moonpool formed by two identical hulls undergoing heave oscillation is investigated by using a viscous fluid flow solver with RNG turbulent model based on OpenFOAM® package. By comparison of experimental and numerical results, it is confirmed the present numerical model can simulate the gap resonance problem in a high level accuracy. Numerical simulations suggest that the resonant amplitude in moonpool decreases dramatically when installing the convex appendages, which is the reason of significant variation of velocity flow field in the vicinity of moonpool. The single convex appendages at the bottom or near the free surface can generate smaller resonant amplitude than that at the middle of moonpool wall. The vortex bubbles from the convex appendages at the moonpool bottom create more energy dissipation than those for the convex appendages in the middle of moonpool and near the free surface. As for the multiple convex appendages, the variation of resonant amplitude with appendages types follows the suppressing characteristics of single convex appendages when heave amplitude is small. However, the additional appendages at the middle of moonpool wall shrink the region of vortex bubbles from the bottom appendages when the heave amplitude is large, leading to the increased resonant amplitude in moonpool. All of these phenomena indicate the complex effect of vortex shedding in the moonpool region on resonant behavior. Finally, the vertical force on each appendage in multiple types is always smaller than that on the appendage in single types, implying the multiple appendages types can reduce the fluid force on the appendage.

Fluorescence tunable thiophene-bis(benzimidazole)-based probes for a cascade trace detection of Hg2+ and lysine: A molecular switch mimic

Six thiophene-bis(benzimidazole)-based molecular probes with tunable fluorescence emission were synthesized for selective Hg2+ detection. Probe 1 contains a thiophene-bis(benzimidazole) unit without an appendage, while probes 2-4 have multiple appendages on benzimidazole rings of the core and probe 6/7 has two biphenyl appendages on the thiophene ring. Fluorescence emissions of all these probes were selectively quenched upon Hg2+ addition, but probe 7 provided the most sensitive detection of Hg2+, giving the highest association constant (Ka (7) = 2.38 × 106 M−1) and the lowest observed and calculated limit of detections (LODs) (5 nM and 0.047 pM, respectively). Thus, the probe 7-Hg2+ complex was further tested for detection of a biomolecule as a next step. Among the various biomolecules tested (including amino acids), L-lysine (Lys) uniquely showed a full restoration of the fluorescence intensity of [probe 7+Hg2+ (1:2)]-complex to the level of the free probe, with an LOD of 5 nM. Thus, a cascade detection of Hg2+ and Lys was attained by probe 7via selective quenching and recovering of the fluorescence intensity, which enables us to build an “ON−OFF−ON” switch and logic gate at a molecular level. The current system was fully studied by various analytical methods such as UV–vis, fluorescence, and 1H NMR spectroscopies, IR, FE-SEM images, and DFT calculations.

Investigation and optimization of appendage influence on the hydrodynamic performance of AUVs

Navigational range is an important attribute of autonomous underwater vehicles (AUVs), and drag reduction efforts have been pursued to improve overall efficiency. Improved efficiency results in a more capable vehicle over all. Historically, the majority of research focused on drag reduction has been concentrated on the optimization of vehicle hull geometry. The influence of the hull appendages on drag, however, has been largely ignored owing to their smaller size. In this study, the impacts of appendage size and position on vehicle drag are investigated using a computational fluid dynamics method. The results indicate that appendages increase more drag because of their impact on the development of turbulence. The investigation of the interactions between multiple appendages fixed on a vehicle hull shows that optimization is necessary for drag reduction. This paper presents an arrangement optimization method for AUV appendages based on the Kriging approximation model and the multi-island genetic algorithm. The results of the optimization show that appendage influence on hydrodynamic performance is directly proportional to its size, and that a distributed arrangement is beneficial for drag reduction.

Morphoanatomy of the ovary and ovule in Bromeliaceae subfamily Tillandsioideae and its systematic relevance

Tillandsioideae are composed of nine genera, most of these with unclear delimitation. The morphoanatomy of ovules and ovaries of 83 species from seven different genera was studied under light or scanning electron microscopy to contribute to the understanding of the relationships in the group. The nucellar epidermis and the parietal tissue showed a regular pattern for all Tillandsioideae. The presence of chalazal appendages, however, and their shape and size varied between the genera analysed. Most species had a single acuminate chalazal appendage. Catopsis was the only genus with multiple appendages. Guzmania and Racinaea lacked this structure. The integuments also presented a variable length and thickness among the different genera. The four to six layers of the outer integument were unique in Catopsis and the three cell layers condition in the inner integument of Tillandsia should be a retained feature as it was also observed in Catopsis. Many characteristics in ovule morphology presented here have great systematic value for distinguishing genera of the Tillandsioideae. In addition, these features can also help in the understanding of ovule evolution in Bromeliaceae as a whole.

COMPARISON OF APPROACHES FOR “NET CLINICAL BENEFIT” IN PATIENTS WITH NON-VALVULAR ATRIAL FIBRILLATION: A NETWORK META-ANALYSES OF RANDOMIZED CONTROL TRIALS

Multiple novel oral anticoagulants (NOACs) and left atrial appendage closure (LAAC) devices have been tested against adjusted dose warfarin (VKA) in randomized controlled trials (RCTs) for stroke prophylaxis in non-valvular atrial fibrillation. No direct comparisons of the efficacy and safety

Molecular taxonomy of Dinemasporium and its allied genera

The taxonomic relationships of three coelomycetous genera, Dinemasporium, Diarimella and Stauronema, were assessed. A total of 43 isolates/specimens of Dinemasporium-like fungi were examined by phylogenetic analysis of internal transcribed spacer sequences of the nuclear rRNA gene and morphological comparisons. Species highly consistent with Diarimella or Stauronema generic concepts failed to form monophyletic groups, but were scattered within the Dinemasporium clade. Diarimella and Stauronema are therefore treated as synonyms of Dinemasporium. An expanded generic concept of Dinemasporium is proposed to accommodate species having conidia with bipolar and lateral appendages (formerly Stauronema) or branched multiple appendages (formerly Diarimella), as well as typical Dinemasporium species having conidia with bipolar unbranched appendages. Eight new species of Dinemasporium — D. ambiguum, D. bambusicola, D. iriomotense, D. japonicum, D. parastrigosum, D. pseudodecipiens, D. rishiriense and D. sasae — are described and illustrated.

The Hox genes Ultrabithorax and abdominal-A specify three different types of abdominalappendage in the springtail Orchesella cincta (Collembola)

BackgroundIn Drosophila and many other insects, the Hox genes Ultrabithorax (Ubx) and abdominal-A (abd-A) suppress limb formation on most or all segments of the abdomen. However, a number of basal hexapod lineages retain multiple appendages on the abdomen. In the collembolans or springtails, three abdominal segments develop specialized organs that originate from paired appendage primordia which fuse at the midline: the first abdominal segment bears the collophore (ventral tube), involved in osmoregulation; the fourth segment bears the furca, the leaping organ, and the third segment bears the retinaculum, which retains the furca at rest. Ubx and abd-A are known to be expressed in the springtail abdomen, but what role they play in specifying these distinct abdominal appendages is not known. This is largely because no genetic model has been established in collembolans or any other non-insect hexapod.ResultsWe have developed a convenient method for laboratory culture of the collembolan Orchesella cincta on defined media, a method for in-situ hybridization to embryos and a procedure for gene knockdown by parental injection of double-stranded RNA (RNAi). We show that Orchesella Ubx transcripts are detectable in the first to third abdominal segments, and abd-A transcripts in the second to fourth segments. Knockdown of Oc-Ubx leads to the homeotic transformation of the collophore into a pair of walking legs (a more anterior identity) but the retinaculum into a furca (a more posterior identity). Knockdown of Oc-abd-A leads to the transformation of the retinaculum into a collophore and of the furca into legs (both anterior transformations). Simultaneous silencing of both Oc-Ubx and Oc-abd-A transformed all three of these appendages into paired legs, but did not cause appendages to develop on the second, or on the most posterior abdominal segments.ConclusionsWe conclude that, in Orchesella, Oc-Ubx alone specifies the collophore on the first and Oc-abd-A alone specifies the furca on the fourth abdominal segment. Oc-Ubx and Oc-abd-A function together, apparently combinatorially, to specify the retinaculum on the third segment. The efficiency of RNAi in Orchesella makes this an attractive model for further genetic studies of development and physiology in basal hexapods.Electronic supplementary materialThe online version of this article (doi:10.1186/2041-9139-5-2) contains supplementary material, which is available to authorized users.

Ischiopagus and Diprosopus in India: Two Pairs of Conjoined Twins Perceived as Incarnations of Hindu Deities

This article briefly reviews two specific types of conjoined twins, ischiopagus and diprosopus, and discusses recent cases of such twins born in India. Some members of the Hindu community worshiped these conjoined twins as incarnations of Hindu deities. In discussing this phenomenon, the authors aim to elucidate certain features of the faith tradition of Hinduism itself. The reception of these conjoined twins as incarnations of Hindu deities can be understood by examining two salient features of Hindu polytheism: the pictorial depiction of Hindu deities with multiple appendages and the concept of an incarnation, or avatar, of a Hindu deity.

Characterization of a Novel Bacillus thuringiensis Phenotype Possessing Multiple Appendages Attached to a Parasporal Body

Bacillus thuringiensis is a bacterium best known for its production of crystal-like bodies comprised of one or more Cry-proteins, which can be toxic to insects, nematodes or cancer cells. Although strains of B. thuringiensis have occasionally been observed with filamentous appendages attached to their spores, appendages in association with their parasporal bodies are extremely rare. Herein we report the characterization of Bt1-88, a bacterial strain isolated from the Caribbean that produces a spore-crystal complex containing six long appendages, each comprised of numerous thinner filaments approximately 10 nm in diameter and 2.5 μm in length. Each of the multi-filament appendages was attached to a single, small parasporal body located at one end of the bacterial spore. Biochemical tests, 16S rDNA gene sequencing, and the identification of two Cry proteins by partial protein sequencing (putatively Cry1A and Cry2A), unambiguously identified Bt1-88 as a strain of B. thuringiensis. Bt1-88 represents the second reported strain of B. thuringiensis possessing a parasporal body/appendage phenotype characterized by one or more long appendages, comprised of numerous filaments in association with a parasporal body. This finding suggests that Bt1-88 is a member of a new phenotypic class of B. thuringiensis, in which the parasporal body may perform a novel structural role through its association with multi-filament appendages.