Skeletal Networks Research Articles

AIEgens-integrated structural color barcodes for binary screening of microRNAs

Highly sensitive microRNAs (miRNA) imaging is of great value in the early diagnosis of tumors. Here, we present a novel aggregation-induced emission luminogens (AIEgens) integrated structural color barcode for binary screening of miRNAs. The barcode particles consist of periodically ordered silica nanoparticles encoded cores, and tetraphenylethylene carboxylate derivatives TPE-(COOH)4 integrated inverse opal polyacrylamide (PAAm) hydrogel shells. As the miRNA probes are decorated in the adjacent TPE-(COOH)4 molecules, the skeletal networks of the hydrogel as well as the TPE-(COOH)4 molecules would be closer with the presence of target miRNA due to the formation of a double helix. This phenomenon could not only result in fluorescence change of the TPE-(COOH)4 molecules, but also contribute to structural color variation of shell hydrogel. These two optical signals could be employed as binary channels for more accurate detection of target miRNAs. During this process, the solid cores of the barcodes could keep stable structural colors, thus providing foundation codes for multiplexed detection of miRNAs. Based on these features, we have demonstrated that the AIEgens-integrated structural color barcodes could realize the multiplexed screening of miRNAs in a microfluidics device for in vitro diagnosis, which implies the potential prospects in biomedical fields.

Highly thermally conductive polymer composite enhanced by constructing a dual thermal conductivity network

AbstractConstructing interconnected thermally conductive networks in a polymer matrix is essential for efficient heat transport in thermally managed materials. Thermally conductive network structures typically have meager thermal resistance, and heat transfer into the material is rapidly exported along such networks. However, increasing the thermally conductive networks inside the polymer matrix is still challenging. This paper prepared high thermal conductivity composites with “primary‐secondary” thermal conductivity networks by combining two processes: constructing three‐dimensional thermally conductive skeletal networks and physically blending fillers, using epoxy resin as the matrix. The performance test results showed that the thermal conductivity of the composites reached 1.65 W/(m K) when the boron nitride (BN) content reached 33.5 wt%, which was 842.8% and 150% higher than that of pure epoxy (EP) and composites with randomly dispersed fillers. This highly efficient heat transfer behavior is mainly due to the synergistic effect of the two‐level thermally conductive network, which weakens the scattering effect of phonons to a great extent. Also, the dielectric properties of the composite material, especially the transport of carriers inside the material under strong electric fields, were discussed in this paper. This work provides ideas and methods for preparing electrical and electronic devices applied to high power density.

High-throughput segmentation, data visualization, and analysis of sea star skeletal networks

The remarkably complex skeletal systems of the sea stars (Echinodermata, Asteroidea), consisting of hundreds to thousands of individual elements (ossicles), have intrigued investigators for more than 150 years. While the general features and structural diversity of isolated asteroid ossicles have been well documented in the literature, the task of mapping the spatial organization of these constituent skeletal elements in a whole-animal context represents an incredibly laborious process, and as such, has remained largely unexplored.To address this unmet need, particularly in the context of understanding structure–function relationships in these complex skeletal systems, we present an integrated approach that combines micro-computed tomography, automated ossicle segmentation, data visualization tools, and the production of additively manufactured tangible models to reveal biologically relevant structural data that can be rapidly analyzed in an intuitive manner.In the present study, we demonstrate this high-throughput workflow by segmenting and analyzing entire skeletal systems of the giant knobby star, Pisaster giganteus, at four different stages of growth. The in-depth analysis, presented herein, provides a fundamental understanding of the three-dimensional skeletal architecture of the sea star body wall, the process of skeletal maturation during growth, and the relationship between skeletal organization and morphological characteristics of individual ossicles.The widespread implementation of this approach for investigating other species, subspecies, and growth series has the potential to fundamentally improve our understanding of asteroid skeletal architecture and biodiversity in relation to mobility, feeding habits, and environmental specialization in this fascinating group of echinoderms.

Three-Dimensional Ternary rGO/VS2/WS2 Composite Hydrogel for Supercapacitor Applications

In recent years, the development of lightweight electrode materials with excellent performance (energy density versus power density) has increased the number of uses for supercapacitors. Creating three-dimensional skeletal network structures with excellent specific capacitance and high energy density is still challenging. This study utilized a straightforward one-pot hydrothermal technique to construct a supercapacitor based on hydrogel 3D skeletal networks comprising rGO nanosheets with VS2/WS2 nanoparticles. The rGO appeared as flakes and layers, interconnected in nature, allowing for more ion transport pathways and a larger active surface area for EDLC performance. The heterostructured VS2 and WS2 nanoparticles were homogeneously anchored to the rGO layers and were porous in the hydrogel structure. The functioning rGO, rGO-VS2, and rGO-VS2-WS2 composite hydrogel electrodes were created without a binder on the Ni foam current collector using a hydraulic press. The rGO-VS2-WS2 composite hydrogel electrode showed excellent supercapacitor performance of 220 F g−1 at 1 A g−1 in 3M KOH electrolyte, which was more than those of the GO (158 F g−1) and rGO-VS2 (199 F g−1) hydrogels under similar conditions. Hydrogel electrodes made of rGO-VS2-WS2 had a power density of 355 Whkg−1 and a high energy density of 30.55 Whkg−1. It maintained a high energy density of up to 21.11 W/kg−1, even at a high power density of 3454 W/kg−1. Given the 3D shape and the excellent surface properties of rGO nanosheets with VS2 and WS2 nanoparticles as the hydrogel, this electrode has essential properties that make it a good choice for making high-performance capacitors.

LncMIR181A1HG is a novel chromatin-bound epigenetic suppressor of early stage osteogenic lineage commitment

Bone formation requires osteogenic differentiation of multipotent mesenchymal stromal cells (MSCs) and lineage progression of committed osteoblast precursors. Osteogenic phenotype commitment is epigenetically controlled by genomic (chromatin) and non-genomic (non-coding RNA) mechanisms. Control of osteogenesis by long non-coding RNAs remains a largely unexplored molecular frontier. Here, we performed comprehensive transcriptome analysis at early stages of osteogenic cell fate determination in human MSCs, focusing on expression of lncRNAs. We identified a chromatin-bound lncRNA (MIR181A1HG) that is highly expressed in self-renewing MSCs. MIR181A1HG is down-regulated when MSCs become osteogenic lineage committed and is retained during adipogenic differentiation, suggesting lineage-related molecular functions. Consistent with a key role in human MSC proliferation and survival, we demonstrate that knockdown of MIR181A1HG in the absence of osteogenic stimuli impedes cell cycle progression. Loss of MIR181A1HG enhances differentiation into osteo-chondroprogenitors that produce multiple extracellular matrix proteins. RNA-seq analysis shows that loss of chromatin-bound MIR181A1HG alters expression and BMP2 responsiveness of skeletal gene networks (e.g., SOX5 and DLX5). We propose that MIR181A1HG is a novel epigenetic regulator of early stages of mesenchymal lineage commitment towards osteo-chondroprogenitors. This discovery permits consideration of MIR181A1HG and its associated regulatory pathways as targets for promoting new bone formation in skeletal disorders.

An Insight into Skeletal Networks Analysis for Smart Hydrogels

AbstractHydrogels are 3D cross‐linked polymer networks. Benefiting from the flexible designs and reasonable constructions of these networks, a large number of smart hydrogels with response characteristics to specific stimuli have received widespread attention and developed rapidly. The skeletal networks composed of the skeletal polymer chains and effectual cross‐links are the soul of such soft materials, and the response behaviors fundamentally depend on the dynamic characteristics of skeletal networks. Herein, the novel concepts of skeletal networks analysis to describe, understand, and guide the advanced designs and applications of smart hydrogels are proposed. Representative glucose‐sensitive hydrogels and DNA‐based smart hydrogels are reviewed to demonstrate the principle of skeletal networks analysis and clarify its practical guidance. Summarizing and classifying the characterizations and conversions of skeletal networks dynamics based on different response mechanisms provides a realistic solution. On this basis, advanced applications of smart hydrogels guided by skeletal networks dynamics including biochemical detection, cell mechanics sensing, drug delivery systems, and dynamic complex soft materials are typically reviewed. The skeletal networks analysis for smart hydrogels is of great significance for understanding the microstructures of hydrogels and guiding the designs of soft materials and their smart applications in the fields of analytical science and advanced materials.

Fabrication and mechanical properties of Ti2AlC/TiAl composites with co-continuous network structure

Ti2AlC/TiAl composites with different volume fractions were prepared by hot pressing technology, and their reinforced structural characteristics and mechanical properties were evaluated. The results showed that when the reinforced phase volume fraction of Ti2AlC was 20%, three-dimensional interpenetrating network structures were formed in the composites. Above 20%, Ti2AlC phase in the composites accumulated and grew to form thick skeletal networks. The microplastic deformation behavior of Ti2AlC phase, such as kink band and delamination, improved the fracture toughness of the composites. Comparative analysis indicated that the uniform and small interconnecting network structures could further reinforce the composites. The bending strengths of composites prepared with 20 vol.% Ti2AlC reached (900.9±45.0) MPa, which was 25.5% higher than that of TiAl matrix. In general, the co-continuous Ti2AlC/TiAl composite with excellent mechanical properties can be prepared by powder metallurgy method.

Basal epidermis collective migration and local Sonic hedgehog signaling promote skeletal branching morphogenesis in zebrafish fins

Teleost fish fins, like all vertebrate limbs, comprise a series of bones laid out in characteristic pattern. Each fin's distal bony rays typically branch to elaborate skeletal networks providing form and function. Zebrafish caudal fin regeneration studies suggest basal epidermal-expressed Sonic hedgehog (Shh) promotes ray branching by partitioning pools of adjacent pre-osteoblasts. This Shh role is distinct from its well-studied Zone of Polarizing Activity role establishing paired limb positional information. Therefore, we investigated if and how Shh signaling similarly functions during developmental ray branching of both paired and unpaired fins while resolving cellular dynamics of branching by live imaging. We found shha is expressed uniquely by basal epidermal cells overlying pre-osteoblast pools at the distal aspect of outgrowing juvenile fins. Lateral splitting of each shha-expressing epidermal domain followed by the pre-osteoblast pools precedes overt ray branching. We use ptch2:Kaede fish and Kaede photoconversion to identify short stretches of shha+basal epidermis and juxtaposed pre-osteoblasts as the Shh/Smoothened (Smo) active zone. Basal epidermal distal collective movements continuously replenish each shha+domain with individual cells transiently expressing and responding to Shh. In contrast, pre-osteoblasts maintain Shh/Smo activity until differentiating. The Smo inhibitor BMS-833923 prevents branching in all fins, paired and unpaired, with surprisingly minimal effects on caudal fin initial skeletal patterning, ray outgrowth or bone differentiation. Staggered BMS-833923 addition indicates Shh/Smo signaling acts throughout the branching process. We use live cell tracking to find Shh/Smo restrains the distal movement of basal epidermal cells by apparent ‘tethering’ to pre-osteoblasts. We propose short-range Shh/Smo signaling promotes these heterotypic associations to couple instructive basal epidermal collective movements to pre-osteoblast repositioning as a unique mode of branching morphogenesis.

Locally Controlled Diffusive Release of Bone Morphogenetic Protein-2 Using Micropatterned Gelatin Methacrylate Hydrogel Carriers.

In this work, a novel and simple bone morphogenetic protein (BMP)-2 carrier is developed, which enables localized and controlled release of BMP-2 and facilitates bone regeneration. BMP-2 is localized in the gelatin methacrylate (GelMA) micropatterns on hydrophilic semi-permeable membrane (SNM), and its controlled release is regulated by the concentration of GelMA hydrogel and BMP-2. The controlled release of BMP-2 is verified using computational analysis and quantified using fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) diffusion model. The osteogenic differentiation of osteosarcoma MG-63 cells is manipulated by localized and controlled BMP-2 release. The calcium deposits are significantly higher and the actin skeletal networks are denser in MG-63 cells cultured in the BMP-2-immobilized GelMA micropattern than in the absence of BMP-2. The proposed BMP-2 carrier is expected to not only act as a barrier membrane that can prevent invasion of connective tissue during bone regeneration, but also as a carrier capable of localizing and controlling the release of BMP-2 due to GelMA micropatterning on SNM. This approach can be extensively applied to tissue engineering, including the localization and encapsulation of cells or drugs.

Sugar, gravel, fish and flowers: Mesoscale cloud patterns in the trade winds

AbstractAn activity designed to characterise patterns of mesoscale (20 to 2,000 km) organisation of shallow clouds in the downstream trades is described. Patterns of mesoscale organisation observed from space were subjectively defined and learned by 12 trained scientists. The ability of individuals to communicate, learn and replicate the classification was evaluated. Nine‐hundred satellite images spanning the area from 48°W to 58°W, 10°N to 20°N for the boreal winter months (December–February) over 10 years (2007/2008 to 2016/2017) were classified. Each scene was independently labelled by six scientists as being dominated by one of six patterns (one of which was “no‐pattern”). Four patterns of mesoscale organisation could be labelled in a reproducible manner, and were labelled Sugar, Gravel, Fish and Flowers. Sugar consists of small, low clouds of low reflectivity, Gravel clouds form along apparent gust fronts, Fish are skeletal networks (often fishbone‐like) of clouds, while Flowers are circular clumped features defined more by their stratiform cloud elements. Both Fish and Flowers are surrounded by large areas of clear air. These four named patterns were identified 40% of the time, with the most common pattern being Gravel. Sugar was identified the least and suggests that unorganised and very shallow convection is unlikely to dominate large areas of the downstream trade winds. Some of the patterns show signs of seasonal and interannual variability, and some degree of scale selectivity. Comparison of typical patterns with radar imagery suggests that even this subjective and qualitative visual inspection of imagery appears to capture several important physical differences between shallow cloud regimes, such as precipitation and radiative effects.

Extracting the mechanisms and kinetic models of complex reactions from atomistic simulation data.

Determining reaction mechanisms and kinetic models, which can be used for chemical reaction engineering and design, from atomistic simulation is highly challenging. In this study, we develop a novel methodology to solve this problem. Our approach has three components: (1) a procedure for precisely identifying chemical species and elementary reactions and statistically calculating the reaction rate constants; (2) a reduction method to simplify the complex reaction network into a skeletal network which can be used directly for kinetic modeling; and (3) a deterministic method for validating the derived full and skeletal kinetic models. The methodology is demonstrated by analyzing simulation data of hydrogen combustion. The full reaction network comprises 69 species and 256 reactions, which is reduced into a skeletal network of 9 species and 30 reactions. The kinetic models of both the full and skeletal networks represent the simulation data well. In addition, the essential elementary reactions and their rate constants agree favorably with those obtained experimentally. © 2019 Wiley Periodicals, Inc.

Arterial Network Geometric Characteristics and Regulation of Capillary Blood Flow in Hamster Skeletal Muscle Microcirculation.

This study was aimed to characterize the geometric arrangement of hamster skeletal muscle arteriolar networks and to assess the in vivo rhythmic diameter changes of arterioles to clarify regulatory mechanisms of the capillary perfusion. The experimental study was carried out in male Syrian hamsters implanted with a plastic chamber in the dorsum skin under pentobarbital anesthesia. The skeletal muscle microvessels were visualized by fluorescence microscopy. The vessel diameters, lengths and the rhythmic diameter changes of arterioles were analyzed with computer-assisted techniques. The arterioles were classified according to a centripetal ordering scheme. In hamster skeletal muscle microvasculature the terminal branchings, differentiated in long and short terminal arteriolar trees (TATs), originated from anastomotic vessels, defined “arcading” arterioles. The long TATs presented different frequencies along the branching vessels; order 4 arterioles had frequencies lower than those observed in the order 3, 2, and 1 vessels. The short TAT order 3 arterioles, directly originating from “arcading” parent vessels, showed a frequency dominating all daughter arterioles. The amplitude of diameter variations in larger vessels was in the range 30–40% of mean diameter, while it was 80–100% in order 3, 2, and 1 vessels. Therefore, the complete constriction of arterioles, caused an intermittent capillary blood perfusion. L-arginine or papaverine infusion caused dilation of arterioles and transient disappearing of vasomotion waves and induced perfusion of all capillaries spreading from short and long TAT arrangements. Therefore, the capillary blood flow was modulated by changes in diameter of terminal arterioles penetrating within the skeletal muscle fibers, facilitating redistribution of blood flow according to the metabolic demands of tissues.

Fractal analysis on the cluster network in metallic liquid and glass

To explore the atomic-level structure of metallic glasses, liquid melt quenched Tantalum was obtained by computer simulations, which mimics the experimental approach to the vitrification of metallic liquids by achieving an unprecedentedly high liquid-quenching rate. Through the local atomic structure analysis of the quenched Tantalum, it is shown that the atomic clusters assemble in space to further form skeletal networks by sharing various linking patterns, i.e. vertex, edge, face or volume linkages. By employing the established box-counting method, the cluster network is revealed to exhibit a fractal characteristic. The fractal dimension of the atomic cluster network is computed to be 2.3–2.5. Compared to other indirect fractal analysis method, the present work first provides a straightforward evidence of fractal structure, which promotes the understanding to the atomic configuration of metallic glasses.

A skeletal double gyroid formed by single coaxial bundles of catechol based bolapolyphiles.

A bolapolyphile, derived from a linear p-terphenyl core with glycerol groups at each end and two octadecyl chains fixed to the same side of the π-conjugated rod, is synthesized and is found to form a new type of self-assembled cubic LC phase with the Ia3[combining macron]d lattice. Each unit cell involves 16 polar aggregates interconnected by 24 coaxial rod-bundles at the single-molecule length, forming two interwoven skeletal networks with three-way junctions, being separated by a continuum of the lateral alkyl chains located around the gyroid minimal surface.

Involvement of membrane skeletal molecules in the Schmidt-Lanterman incisure in Schwann cells.

Membrane skeletal networks form a two-dimensional lattice structure beneath erythrocyte membranes. 4.1R-MPP (membrane palmitoylated protein) 1-glycophorin C is one of the basic molecular complexes of the membrane skeleton. An analogous molecular complex, 4.1G-MPP6-cell adhesion molecule 4 (CADM4), is incorporated into the Schmidt-Lanterman incisure (SLI), a truncated cone shape in the myelin internode that is a specific feature of myelinated nerve fibers formed in Schwann cells in the peripheral nervous system. In this review, the dynamic structure of peripheral nerve fibers under stretching conditions is demonstrated using in vivo cryotechnique. The structures of nerve fibers had a beaded appearance, and the heights of SLI circular-truncated cones increased at the narrow sites of nerve fibers under the stretched condition. The height of SLI-truncated cones was lower in 4.1G-deficient nerve fibers than in wild-type nerve fibers. 4.1G was essential for the molecular targeting of MPP6 and CADM4 in SLI. The signal transduction protein, Src, was also involved in the 4.1G-MPP6-CADM4 molecular complex. The phosphorylation of Src was altered by the deletion of 4.1G. Thus, we herein demonstrate a membrane skeletal molecular complex in SLI that has potential roles in the regulation of adhesion and signal transduction as well as in structural stability in Schwann cells.

Anatomical Network Comparison of Human Upper and Lower, Newborn and Adult, and Normal and Abnormal Limbs, with Notes on Development, Pathology and Limb Serial Homology vs. Homoplasy.

How do the various anatomical parts (modules) of the animal body evolve into very different integrated forms (integration) yet still function properly without decreasing the individual’s survival? This long-standing question remains unanswered for multiple reasons, including lack of consensus about conceptual definitions and approaches, as well as a reasonable bias toward the study of hard tissues over soft tissues. A major difficulty concerns the non-trivial technical hurdles of addressing this problem, specifically the lack of quantitative tools to quantify and compare variation across multiple disparate anatomical parts and tissue types. In this paper we apply for the first time a powerful new quantitative tool, Anatomical Network Analysis (AnNA), to examine and compare in detail the musculoskeletal modularity and integration of normal and abnormal human upper and lower limbs. In contrast to other morphological methods, the strength of AnNA is that it allows efficient and direct empirical comparisons among body parts with even vastly different architectures (e.g. upper and lower limbs) and diverse or complex tissue composition (e.g. bones, cartilages and muscles), by quantifying the spatial organization of these parts—their topological patterns relative to each other—using tools borrowed from network theory. Our results reveal similarities between the skeletal networks of the normal newborn/adult upper limb vs. lower limb, with exception to the shoulder vs. pelvis. However, when muscles are included, the overall musculoskeletal network organization of the upper limb is strikingly different from that of the lower limb, particularly that of the more proximal structures of each limb. Importantly, the obtained data provide further evidence to be added to the vast amount of paleontological, gross anatomical, developmental, molecular and embryological data recently obtained that contradicts the long-standing dogma that the upper and lower limbs are serial homologues. In addition, the AnNA of the limbs of a trisomy 18 human fetus strongly supports Pere Alberch's ill-named "logic of monsters" hypothesis, and contradicts the commonly accepted idea that birth defects often lead to lower integration (i.e. more parcellation) of anatomical structures.

Modular Truss-Z system for self-supporting skeletal free-form pedestrian networks

This paper presents the concept of Truss-Z (TZ) - a skeletal system for pedestrian traffic which is composed of only two modules and allows the creation of complex three-dimensional self-supporting networks connecting any number of terminals in a given environment. TZ is intended as a universal, feasible and practical system for newly designed situations and most importantly, for retrofitting, especially where the use of heavy equipment is impossible or uneconomic. TZ allows automated creation of optimal spatial links where the only required inputs are the coordinates of the terminals and the geometry of the obstacles. As an example a six-terminal network created with a backtracking based algorithm is shown. An alternative method of aligning consecutive modules to a given 3D path is also presented. A preliminary static analysis of the TZ module is carried out - the topological qualities of rigidity and independence are demonstrated.

Insulin-like growth factor-I and bone: lessons from mice and men

Studies of humans and animals have illustrated a strong association between insulin-like growth factor (IGF)-I and skeletal acquisition. However, the precise molecular and cellular mechanisms underlying this effect still largely remain unknown. Recent advances in molecular and genetic techniques for in vivo studies provide excellent tools for us to explore how circulating and skeletal insulin-like growth factor-I (IGF-I) may affect not only peak bone mass but also bone loss. This review highlights recent findings that shed new light on the interaction of the IGF-I signaling pathway with other skeletal networks, and the role of IGF-I in the bone marrow milieu.

Structures of Diamond-Like Carbon Films

The structures of diamond-like carbon (DLC) films, including a-C:H, a-C, ta-C:H and ta-C films have been investigated as a random covalent network with a dense film structure. The results show that sp2 C in a-C:H and a-C films tends to form olefinic and aromatic groups while sp3 C in ta-C:H and ta-C films tends to form single or multiple sixfold groups. The hydrogen atoms in hydrogenated DLC films contribute to stabilizing the carbon skeletal networks. The film structures are well related to their properties such as optical gaps, density and hardness. The results also indicate that the high density and the extreme hardness of ta-C films are attributed to the forming of large sp3 C bonded sixfold groups.

High-resolution en-face visualization of the cardiomyocyte plasma membrane reveals distinctive distributions of spectrin and dystrophin

The actin-binding proteins, spectrin and dystrophin, are key components of the plasma membrane-associated cytoskeleton of the cardiac muscle cell. From confocal immunofluorescence studies, the distribution of spectrin appears to overlap with that of dystrophin, but the precise functional differentiation, molecular distributions and spatial relationship of these two cytoskeletal systems remain unclear. Freeze-fracture replica immuno-electron microscopy, in parallel with immunofluorescence/confocal microscopy, were applied to examine at high resolution the spatial relationships between the spectrin and dystrophin membrane-associated cytoskeleton systems in cardiac muscle. Application of freeze-fracture replica cytochemistry, with single and double immunogold labeling, permitted simultaneous examination of the organization of spectrin and dystrophin in en-face views of the plasma membrane at high resolution. In contrast to the close spatial relationship previously demonstrated for dystrophin and β-dystroglycan, no association between the gold label marking dystrophin and that marking spectrin was observed. Our freeze-fracture cytochemical results suggest that the two membrane skeletal networks formed by dystrophin and spectrin in cardiac muscle are independently organized, implying that whatever overlap of function (e.g., in structural support to the plasma membrane) may exist between them, the two systems may each have additional distinctive roles.