Number Of Fibers Research Articles

Validation of positional candidates Rps6ka6 and Pou3f4 for a locus associated with skeletal muscle mass variability.

Genetic variability significantly contributes to individual differences in skeletal muscle mass; however, the specific genes involved in that process remain elusive. In this study, we examined the role of positional candidates, Rps6ka6 and Pou3f4, of a chromosome X locus, implicated in muscle mass variability in CFW laboratory mice. Histology of hindlimb muscles was studied in CFW male mice carrying the muscle "increasing" allele C (n = 15) or "decreasing" allele T (n = 15) at the peak marker of the locus, rs31308852, and in the Pou3f4y/- and their wild-type male littermates. To study the role of the Rps6ka6 gene, we deleted exon 7 (Rps6ka6-ΔE7) using clustered regularly interspaced palindromic repeats-Cas9 based method in H2Kb myogenic cells creating a severely truncated RSK4 protein. We then tested whether that mutation affected myoblast proliferation, migration, and/or differentiation. The extensor digitorum longus muscle was 7% larger (P < 0.0001) due to 10% more muscle fibers (P = 0.0176) in the carriers of the "increasing" compared with the "decreasing" CFW allele. The number of fibers was reduced by 15% (P = 0.0268) in the slow-twitch soleus but not in the fast-twitch extensor digitorum longus (P = 0.2947) of Pou3f4y/- mice. The proliferation and migration did not differ between the Rps6ka6-ΔE7 and wild-type H2Kb myoblasts. However, indices of differentiation (myosin expression, P < 0.0001; size of myosin-expressing cells, P < 0.0001; and fusion index, P = 0.0013) were significantly reduced in Rps6ka6-ΔE7 cells. This study suggests that the effect of the X chromosome locus on muscle fiber numbers in the fast-twitch extensor digitorum longus is mediated by the Rps6ka6 gene, whereas the Pou3f4 gene affects fiber number in slow-twitch soleus.

Durotaxis and Topotaxis Orchestrated Guidance on Cell Migration in 3D Printed Scaffold/Hydrogel Composite

Printing three-dimensional (3D) scaffolds with suitable mechanical cues is an effective strategy for guiding tissue regeneration by inducing cell migration and growth. Nevertheless, many studies considered only one type of cue for 3D tissue engineering scaffold fabrication, such as topological cues, which is insufficient. To realize durotaxis- and topotaxis-orchestrated guidance on cell migration, a 3D printed scaffold/hydrogel composite was fabricated in this study. The porous scaffold provided a topological cue (topotaxis), and the combined hydrogel provided a compliance cue (durotaxis). The results indicated that the thin fibers of the scaffold induced cell migration, and the larger pore size and directed fiber number of the scaffold led to more uniform cell orientation (topotaxis). Furthermore, when collagen was cured to cover the scaffold to result in a compliance change, the cells in the collagen still sensed the scaffold topological cue and migrated along it (durotaxis). Collagen also provides a living space and nutrition for cells, thereby significantly increasing their number. The effects of durotaxis and topotaxis synthesis provide a promising solution for tissue engineering scaffold applications.

METHOD OF EVALUATION THE EFFICIENCY OF FIBER-OPTIC CABLES MODELS WITH MULTI-MODULAR DESIGN BASED ON MASS AND DIMENSIONAL INDICATORS

Context. Today, the leading cable production plants in many countries of the world manufacture single- and multi-module designs of fiber-optic cables (FOC) with different protective covers and the number of fibers. This creates a wide range of possible FOC models for different consumer (buyer) requirements. However, the lack of openness of prices for FOC for the consumer, in particular for the project organization, and the desire of the manufacturer to save on production creates a need for the development and research of a method for evaluating the effectiveness of FOC of a multi-module design. In the work, it is proposed to do this by analyzing a number of optical cable models according to parameters-criteria – the compactness coefficient and the economic efficiency coefficient of the FOC by diameter. Objective. To develop a method of evaluation the efficiency of fiber-optic cables models with multi-modular design based on mass-dimensional indicators, which will allow to quickly choose an appropriate model of the FOC with the given initial data. Method. A method of evaluating the efficiency of the FOC modular design has been developed and proposed. It is based on the comparison of cable models and the selection of the most appropriate of them at given initial data. The paper proposed and introduced parameters-criteria for this – the compactness coefficient υ and the efficiency coefficient according to the diameter of the cable E0 – which show the connection of the design characteristics of the FOC to a certain parameter of its structure. At the same time, the most effective model (design) of the FOC compared to the basic models in terms of technical conditions, both from the point of view of the manufacturer and the customer, consists in lower material costs for its production while simultaneously ensuring the specified requirements for the cable (first of all, number of fibers and mechanical strength). This will allow, at the stage of cable design, to make an appropriate choice of its model with given initial parameters and to develop such a design of the FOC, which will allow to minimize the dimensions (and therefore the material capacity and cost) of the model without losing its quantitative and qualitative characteristics. Results. The paper presents the results of the development and research of the method of evaluating the efficiency of the FOC with multi-module structure based on mass and dimensional indicators. For example, using the developed method, it is shown that it is possible to choose a FOC model with a diameter smaller by 10.9% and save 15.5% of the cable cost for each kilometer of the fiber optic communication line while ensuring the initial requirements for the cable. Conclusions. The scientific novelty of the work results is that, method of evaluation the efficiency of a modular FOC design has been first developed, which allows at the cable design stage to compare the model with the cable design according to the technical conditions (TC) and the appropriate choice of this model with the given initial parameters. The practical significance lies in the possibility of using this method to make an accelerated selection of the cable model at the stage of its design, while simultaneously providing the necessary capacity of the FOC with optical fibers and minimizing the cost of its materials and dimensions.

454 Utilization of Adipose-Derived Stem Cells in Cranial Nerve Regeneration: A Systematic Review

INTRODUCTION: Large peripheral nerve injuries may require surgical reconnection. Cell-based therapies have also been investigated for nerve regeneration. METHODS: PubMed and Embase databases were used to search for primary studies reporting the use ADSCs in the regeneration of cranial nerves. A total of 12 studies were included which all presented data on specific neural injury, therapy, and functional outcomes. RESULTS: Eight studies focused on the facial nerve (66.7%), two on the optic nerve (16.7%), one on the olfactory nerve (8.3%), and one on the hypoglossal nerve (8.3%). One study applied ADSCs to human cranial nerve injuries, while the remainder studied animal models. In these studies, ADSC groups had higher numbers of myelinated fibers, increased myelin thickness and diameter of muscle fibers as well as greater magnitude of compound muscle action potentials (CMAP) when compared to controls. In studies focused on optic nerve regeneration, significant improvements across visual tests were observed. CONCLUSIONS: ADSCs demonstrate potential utility in regard to their ability to facilitate functional recovery of cranial nerves in humans as well as animal models. Further investigation into the use of ADSC should be pursued in both animal and early human studies to validate the findingsof previous literature.

Cryopreserved Umbilical Cord Extract Restores the Skin Structure in Ovariectomized Rats

The research covers the specific effect of human umbilical cord cryoextract and the culture medium of its mesenchymal stromal cells in comparison with synthetic hyaluronic acid on the skin regeneration in female rats with simulated aging. The specified substances were administered intradermally to ovariectomized animals. The injection of human umbilical cord cryoextract into animals with a model of skin aging was established to restore the skin structure already 2 weeks after the injections. Thickening of the epidermis and dermis, phenomenon of cell proliferation, and an increased number of collagen fibers as well as blood vessels were observed. Four weeks after the last injection, the skin condition was normalized to the level of intact animals. Administration of the culture medium of mesenchymal stromal cells of the umbilical cord also led to an increased number of collagen fibers, cell proliferation, contouring of skin layers, but had a less pronounced effect compared to the injections of cryoextract on the indices of the dermis and epidermis thickness. Injections of synthetic hyaluronic acid led to "rejuvenation" of the upper layers of skin and had a less pronounced manifestation compared to the effect of human umbilical cord derivatives.

The key role of myostatin b in somatic growth in fishes derived from distant hybridization.

The basic mechanism of heterosis has not been systematically and completely characterized. In previous studies, we obtained three economically important fishes that exhibit rapid growth, WR (WCC ♀ × RCC ♂), WR-II (WR ♀ × WCC ♂), and WR-III (WR-II ♀ × 4nAU ♂), through distant hybridization. However, the mechanism underlying this rapid growth remains unclear. In this study, we found that WR, WR-II, and WR-III showed muscle hypertrophy and higher muscle protein and fat contents compared with their parent species (RCC and WCC). Candidate genes responsible for this rapid growth were then obtained through an analysis of 12 muscle transcriptomes. Notably, the mRNA level of mstnb (myostatin b), which is a negative regulator of myogenesis, was significantly reduced in WR, WR-II, and WR-III compared with the parent species. To verify the function of mstnb, a mstnb-deficient mutant RCC line was generated using the CRISPR-Cas9 technique. The average body weight of mstnb-deficient RCC at 12 months of age was significantly increased by 29.57% compared with that in wild-type siblings. Moreover, the area and number of muscle fibers were significantly increased in mstnb-deficient RCC, indicating hypertrophy and hyperplasia. Furthermore, the muscle protein and fat contents were significantly increased in mstnb-deficient RCC. The molecular regulatory mechanism of mstnb was then revealed by transcription profiling, which showed that genes related to myogenesis (myod, myog, and myf5), protein synthesis (PI3K-AKT-mTOR), and lipogenesis (pparγ and fabp3) were highly activated in hybrid fishes and mstnb-deficient RCC. This study revealed that low expression or deficiency of mstnb regulates somatic growth by promoting myogenesis, protein synthesis, and lipogenesis in hybrid fishes and mstnb-deficient RCC, which provides evidence for the molecular mechanism of heterosis via distant hybridization.

Abnormal microstructure of corpus callosum in children with primary nocturnal enuresis: a DTI study.

Primary nocturnal enuresis (PNE) is a common childhood disorder with abnormal sleep or arousal. The corpus callosum (CC) continues to develop into adulthood and plays an important role in sleep arousal. This study aimed to evaluate the microstructure of the CC in children with PNE. Diffusion tensor imaging (DTI) indices were extracted throughout the CC and its seven subregions were compared between the children with PNE and healthy children (HC). The correlation between abnormal DTI indices of the CC and cognitive condition was also tested. Compared to HC, decreased fiber number (NF) (F = 8.492, PFDR = 0.032) and fractional anisotropy (FA) value (F = 8.442, PFDR = 0.040) were found in the posterior midbody of the CC, increased RD was found in the posterior midbody (F = 6.888, PFDR = 0.040) and isthmus (F = 7.967, PFDR = 0.040) in children with PNE. The reduction of FA value was more obvious in boys than girls with PNE. In children with PNE, there was a significant positive correlation between the NF of the posterior midbody and full IQ (r = 0.322, P = 0.025) and between the FA value and the general knowledge memory (r = 0.293, P = 0.043). This study provides imaging evidence for abnormalities in the microstructure of the CC in children with PNE, especially in male PNE, which might affect the children's cognitive performance.

Network visualization of genes involved in skeletal muscle myogenesis in livestock animals

BackgroundMuscle growth post-birth relies on muscle fiber number and size. Myofibre number, metabolic and contractile capacities are established pre-birth during prenatal myogenesis. The aim of this study was to identify genes involved in skeletal muscle development in cattle, sheep, and pigs - livestock.ResultsThe cattle analysis showed significant differences in 5043 genes during the 135–280 dpc period. In sheep, 444 genes differed significantly during the 70–120 dpc period. Pigs had 905 significantly different genes for the 63–91 dpc period.The biological processes and KEGG pathway enrichment results in each species individually indicated that DEGs in cattle were significantly enriched in regulation of cell proliferation, cell division, focal adhesion, ECM-receptor interaction, and signaling pathways (PI3K-Akt, PPAR, MAPK, AMPK, Ras, Rap1); in sheep - positive regulation of fibroblast proliferation, negative regulation of endothelial cell proliferation, focal adhesion, ECM-receptor interaction, insulin resistance, and signaling pathways (PI3K-Akt, HIF-1, prolactin, Rap1, PPAR); in pigs - regulation of striated muscle tissue development, collagen fibril organization, positive regulation of insulin secretion, focal adhesion, ECM-receptor interaction, and signaling pathways (PPAR, FoxO, HIF-1, AMPK). Among the DEGs common for studied animal species, 45 common genes were identified. Based on these, a protein-protein interaction network was created and three significant modules critical for skeletal muscle myogenesis were found, with the most significant module A containing four recognized hub genes - EGFR, VEGFA, CDH1, and CAV1. Using the miRWALK and TF2DNA databases, miRNAs (bta-miR-2374 and bta-miR-744) and transcription factors (CEBPB, KLF15, RELA, ZNF143, ZBTB48, and REST) associated with hub genes were detected. Analysis of GO term and KEGG pathways showed that such processes are related to myogenesis and associated with module A: positive regulation of MAP kinase activity, vascular endothelial growth factor receptor, insulin-like growth factor binding, focal adhesion, and signaling pathways (PI3K-Akt, HIF-1, Rap1, Ras, MAPK).ConclusionsThe identified genes, common to the prenatal developmental period of skeletal muscle in livestock, are critical for later muscle development, including its growth by hypertrophy. They regulate valuable economic characteristics. Enhancing and breeding animals according to the recognized genes seems essential for breeders to achieve superior gains in high-quality muscle mass.

LEDT and Idebenone treatment modulate autophagy and improve regenerative capacity in the dystrophic muscle through an AMPK-pathway.

Considering the difficulties and challenges in Duchenne muscular dystrophy (DMD) treatment, such as the adverse effects of glucocorticoids, which are the main medical prescription used by dystrophic patients, new treatment concepts for dystrophic therapy are very necessary. Thus, in this study, we explore the effects of photobiomodulation (PBM; a non-invasive therapy) and Idebenone (IDE) treatment (a potent antioxidant), applied alone or in association, in dystrophic muscle cells and the quadriceps muscle, with special focus on autophagy and regenerative pathways. For the in vitro studies, the dystrophic primary muscle cells received 0.5J LEDT and 0.06μM IDE; and for the in vivo studies, the dystrophic quadriceps muscle received 3J LEDT and the mdx mice were treated with 200mg/kg IDE. LEDT and IDE treatment modulate autophagy by increasing autophagy markers (SQSTM1/p62, Beclin and Parkin) and signaling pathways (AMPK and TGF-β). Concomitantly, the treatments prevented muscle degeneration by reducing the number of IgG-positive fibers and the fibers with a central nucleus; decreasing the fibrotic area; up-regulating the myogenin and MCH-slow levels; and down-regulating the MyoD and MHC-fast levels. These results suggest that LEDT and IDE treatments enhance autophagy and prevented muscle degeneration in the dystrophic muscle of the experimental model. These findings illustrate the potential efficacy of LEDT and IDE treatment as an alternative therapy focused on muscle recovery in the dystrophic patient.

Trilobatin contributes to the improvement of myopathy in a mouse model of Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) occurs due to genetic mutations that lead to a deficiency in dystrophin production and consequent progressive degeneration of skeletal muscle fibres, through oxidative stress and an exacerbated inflammatory process. The flavonoid trilobatin (TLB) demonstrates antioxidant and anti-inflammatory potential. Its high safety profile and effective action make it a potent therapy for the process of dystrophic muscle myonecrosis. Thus, we sought to investigate the action of TLB on damage in a DMD model, the mdx mouse. Eight-week-old male animals were treated with 160 mg/kg/day of trilobatin for 8 weeks. Control animals were treated with saline. Following treatment, muscle strength, serum creatine kinase (CK) levels, histopathology (necrotic myofibres, regenerated fibres/central nuclei, Feret's diameter and inflammatory area) and the levels of catalase and NF-κB (western blotting) of the quadriceps (QUA), diaphragm (DIA) and tibialis anterior (TA) muscles were measured. TLB was able to significantly increase muscle strength and reduce serum CK levels in dystrophic animals. The QUA of mdx mice showed a reduction in catalase and the number of fibres with a centralized nucleus after treatment with TLB. In the DIA of dystrophic animals, TLB reduced the necrotic myofibres, inflammatory area and NF-κB and increased the number of regenerated fibres and the total fibre diameter. In TA, TLB increased the number of regenerated fibres and reduced catalase levels in these animals. It is concluded that in the mdx experimental model, treatment with TLB was beneficial in the treatment of DMD.

A novel physiotherapeutic approach for the treatment of Os Naviculare: A case study.

Background: Os naviculare in general alters the functional and anatomical balances of the longitudinal plantar arch. A substantial number of the posterior tibialis tendon fibers insert on the accessory ossicle instead of its insertion on tarsal and metatarsal bones resulting in unbalanced stress forces on the tendon. The presence of an accessory navicular type II or type III is a risk factor for PTT tendinopathy and possible PTT tear. Methodology: In this single subject case study, the participant reported with the pre-diagnosed Os naviculare. On examination at initial presentation, the navicular tuberosity of the affected foot was prominent as compared to the contralateral limb. The site was tender on palpation. Ankle range of motion was within normal ranges except ankle dorsiflexion was slightly compromised. Mild pain on active and resisted was noted. Functional tests like star excursion balance test, single leg standing could not be performed due to pain. Pre and post protocol assessment was graded and measured on Cumberland ankle instability tool. The tenderness was recorded using numeric pain rating scale. Star excursion balance test was performed one on 8th day and post protocol. MWM was performed at distal tibiofibular joint on 6 days every week for 3 weeks alongside the conventional regime exercises and ultrasound was applied post treatment session. Result: Result of this study suggested that addition of MWM of distal tibiofibular joint in the conservative exercise protocol was effective in the reduction of pain, dysfunction and improved dynamic control. Conclusion: The results of this study suggests that the addition of MWM of distal tibiofibular joint alongside conservative management shows appreciable effect in improving dysfunction, dynamic stability and reducing pain in individual with congenital Os naviculare.

Collagen modifications predictive of lymph node metastasis in dogs with carcinoma in mixed tumours.

Mixed tumours in the canine mammary gland are the most common histological type in routine diagnosis. In general, these neoplasms have a favourable prognosis that does not evolve into metastatic disease. However, some cases develop into lymph node metastases and are associated with worse patient survival rates. Here is a retrospective study of 46 samples of primary mixed tumours of the canine mammary gland: 15 cases of benign mixed tumours (BMT), 16 cases of carcinoma in mixed tumours without lymph node metastasis (CMT), and 15 cases of carcinomas in mixed tumours with lymph node metastasis (CMTM). In addition, we selected 23 cases of normal mammary glands (NMT) for comparison. The samples were collected from biopsies performed during nodulectomy, simple mastectomy, regional mastectomy, or unilateral/bilateral radical mastectomy. We used multiphoton microscopy, second harmonic generation, and two-photon excited fluorescence, to evaluate the characteristics of collagen fibres and cellular components in biopsies stained with haematoxylin and eosin. We performed Ki67, ER, PR, and HER-2 immunostaining to define the immunophenotype and COX-2. We showed that carcinomas that evolved into metastatic disease (CMTM) present shorter and wavier collagen fibres as compared to CMT. When compared to NMT and BMT the carcinomas present a smaller area of fibre coverage, a larger area of cellular coverage, and a larger number of individual fibres. Furthermore, we observed a correlation between the strong expression of COX-2 and a high rate of cell proliferation in carcinomas with a smaller area covered by cell fibres and a larger number of individual fibres. These findings highlight the fundamental role of collagen during tumour progression, especially in invasion and metastatic dissemination.

Normal subalgebras of a polynomial ring

Let A be a finitely generated subalgebra of a polynomial ring k[x,y,z] over the complex field k. Assuming that A is normal, we clarify the structure of A under additional assumptions if dim⁡A≥2. If dim⁡A=2 and A is regular, then Spec A has an A1-fibration over P1 or A1 with restrictions on the number of multiple fibers (see Theorem 3). If dim⁡A=3, we assume that A is cofinite, i.e., k[x,y,z] is a finite A-module, and A contains a coordinate x. Then either A is a polynomial ring (see Theorem 6) or the invariant subring k[x,u,v]G with respect to a small finite subgroup G of GL(2,k) (see section 4). The results in section 4 are generalized in the next section.

Evidence for chronic headaches induced by pathological changes of myodural bridge complex

Clinical studies have shown that there may be a certain relationship between pathological changes of the myodural bridge complex (MDBC) and chronic headaches of unknown cause. But there is still a lack of experimental evidence to explain the possible mechanism. This study aims to further confirm this relationship between MDBC and chronic headaches and explore its potential occurrence mechanism in rats. Bleomycin (BLM) or phosphate-buffered saline (PBS) was injected into the myodural bridge fibers of rats to establish the hyperplastic model of MDBC. After 4 weeks, the occurrence of headaches in rats was evaluated through behavioral scores. The immunohistochemistry staining method was applied to observe the expression levels of headache-related neurotransmitters in the brain. Masson trichrome staining results showed that the number of collagen fibers of MDBC was increased in the BLM group compared to those of the other two groups. It revealed hyperplastic changes of MDBC. The behavioral scores of the BLM group were significantly higher than those of the PBS group and the blank control group. Meanwhile, expression levels of CGRP and 5-HT in the headache-related nuclei of the brain were increased in the BLM group. The current study further confirms the view that there is a relationship between pathological changes of MDBC and chronic headaches of unknown cause. This study may provide anatomical and physiological explanations for the pathogenesis of some chronic headaches of unknown cause.

Numerical Simulation of the Passive Radiative Cooling Fabric Based on Fiber‐Yarn‐Texture‐Doping Particle 3D Model

AbstractDeveloping passive radiative cooling fabrics could effectively prevent the harmful consequences of global warming, including heat stress and other related illnesses. By enhancing the material compositions and optimizing the structural parameters of conventional fabrics, the creation of radiative cooling fabric that offers both comfort and durability holds great potential. However, the researched simulation models are over‐simplistic, rendering it challenging to precisely portray the fine fabric's structure with the low accuracy of optical properties prediction. In this work, a high‐fidelity model is developed for fabric structure, which allows for precise control of structural parameters of fiber, yarn, texture, and doping particles. Subsequently, by utilizing the FDTD Solutions software, the optical performance of the fabric model is successfully addressed. Furthermore, the coupled heat transfer equation is employed to determine the actual cooling effect of the fabric. It is observed that doping 1% TiO2 nanoparticles and increasing the number of fibers significantly enhances the solar reflectivity, resulting in a cooling effect of approximately 2 °C. To maintain the skin temperature of 34°C, the additional cooling energy required would be reduced by 36 W m−2. These findings are expected to provide crucial guidance and predictions for the development of passive radiative cooling fabrics.

Flavones in pomelo peel resist fibril formation of human islet amyloid polypeptide

ObjectiveExploring the formation and aggregation of human islet amyloid polypeptide (hIAPP) (amylin) fibers is significant for promoting the prevention and treatment of type II diabetes mellitus (T2DM). Flavones in pomelo peel have visible biological activity in the anti-diabetes aspect. The present study aimed to investigate the effects of five flavones [naringin (NRG), narirutin (NRR), nobiletin (NOB), sinensetin (SIN), and neohesperidin (NHP)] in pomelo peel on peptide aggregation and explore its possible mechanisms. The cell viability of flavones against peptide aggregation was also evaluated. MethodsThe thioflavin T (ThT) assay and transmission electron microscopy (TEM) were used for evaluating the inhibition and disaggregation of flavones on peptide aggregation. The interaction mechanism was analyzed by endogenous fluorescence, molecular dynamics (MD) simulations, ultraviolet spectroscopy (UV) and isothermal titration calorimetry (ITC) experiments. The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and immune assays were performed to characterize the cell viability of flavones against peptide aggregation. ResultsThe five flavones showed a decrease in fluorescence intensity, fiber number and size under incubation with different molar ratios of hIAPP. The compounds can bind to the aromatic tyrosine (Tyr) residueTyr 37, resulting in the intrinsic fluorescence quenching of the peptides. Five flavones can form hydrogen bonds with hIAPP, which is likely to be based on their phenolic hydroxyl structure. They showed strong binding affinity with peptides. The reaction system of NRG and NRR observed an exothermic reaction, and the others were endothermic reactions. The absorption peaks of the compounds with hIAPP changed and showed hypochromic effects, indicating that there may be π-π stacking interaction. Flavones noticeably increased the cell viability in the presence of amyloid peptides and reduced the absorption intensity induced by peptide oligomers. ConclusionFive flavones in pomelo peel have inhibitory and depolymerization effects on amyloid fibrils, and can significantly protect cells from the toxic effect of hIAPP and reduce the production of toxic oligomers.

Bond strength model between steel rebar and ultrahigh performance concrete containing coarse aggregates

To clarify the bond performance between steel rebar and ultrahigh performance concrete containing coarse aggregates (UHPC-CA), a total of 33 pull out specimens was cast. The effects of coarse aggregate particle size, coarse aggregate content, and steel fiber content on the failure modes and bond stress-slip curves of the specimens were studied. Based on the virtual crack model, considering the tensile contribution of steel fibers and the bridging effect of coarse aggregates, a model for the bond strength between UHPC-CA and steel rebar was established. The research findings indicated that there was a corresponding matching relationship between coarse aggregate particle size and the spacing of steel rebar ribs. In the 5–8 mm particle size group, the specimens showed 7.95% and 9.01% increases in bond strength compared to the 3–5 mm and 8–10 mm particle size groups, respectively. When the coarse aggregate content of UHPC-CA was 20%, the bond strength was the highest, increasing by 11.39% compared to specimens without coarse aggregates. The bond strength first increased and then decreased with increasing steel fiber content. Excessive steel fiber content could lead to the clustering of steel fibers, reducing the effective number of steel fibers contributing to toughening. The calculated results from the established bond strength model were compared with experimental and literature results, yielding an average ratio of 0.993 and a standard deviation of 0.166. This model effectively predicts the bond strength between UHPC-CA and steel rebar.

Extraction and characterization of fiber from the flower stalk of Sansevieria cylindrica.

A number of natural fibers are being proposed for use in composite materials, especially those extracted from local plants, especially those able to grow spontaneously as they are cost-efficient and have unexplored potential. Sansevieria cylindrica, within the Asparagaceae (previously Agavacae) family, has recently been considered for application in polymer and rubber matrix composites. However, its characterization and even the sorting out of technical fiber from the stem remains scarce, with little available data, as is often the case when the fabrication of textiles is not involved. In this study, Sansevieria cylindrica fibers were separated down to the dimensions of a filament at an 8-15 micron diameter from the stem of the plant, then characterized physically and chemically, using Fourier transform infrared spectroscopy (FTIR), morphologically by scanning electron microscopy (SEM), as well as their thermal degradation, by thermogravimetric analysis (TGA). Their crystallinity surface roughness was measured by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The results indicate over 70% cellulose fibers content with a very high crystallinity (92%) and small crystallite size (1.45 nm), which suggests a low water absorption, with thermal degradation peaking at 294°C. Despite this, due to the significant porosity of the cellular structure, the density of 1.06 g cm-3 is quite low for a mainly cellulose fiber. Roughness measurements indicate that the porosities and foamy structure result in a highly negative skewness (-3.953), in the presence of deep valleys, which may contribute to an effective relation with a covering resin.

Computational models of compound nerve action potentials: Efficient filter-based methods to quantify effects of tissue conductivities, conduction distance, and nerve fiber parameters.

Peripheral nerve recordings can enhance the efficacy of neurostimulation therapies by providing a feedback signal to adjust stimulation settings for greater efficacy or reduced side effects. Computational models can accelerate the development of interfaces with high signal-to-noise ratio and selective recording. However, validation and tuning of model outputs against in vivo recordings remains computationally prohibitive due to the large number of fibers in a nerve. We designed and implemented highly efficient modeling methods for simulating electrically evoked compound nerve action potential (CNAP) signals. The method simulated a subset of fiber diameters present in the nerve using NEURON, interpolated action potential templates across fiber diameters, and filtered the templates with a weighting function derived from fiber-specific conduction velocity and electromagnetic reciprocity outputs of a volume conductor model. We applied the methods to simulate CNAPs from rat cervical vagus nerve. Brute force simulation of a rat vagal CNAP with all 1,759 myelinated and 13,283 unmyelinated fibers in NEURON required 286 and 15,860 CPU hours, respectively, while filtering interpolated templates required 30 and 38 seconds on a desktop computer while maintaining accuracy. Modeled CNAP amplitude could vary by over two orders of magnitude depending on tissue conductivities and cuff opening within experimentally relevant ranges. Conduction distance and fiber diameter distribution also strongly influenced the modeled CNAP amplitude, shape, and latency. Modeled and in vivo signals had comparable shape, amplitude, and latency for myelinated fibers but not for unmyelinated fibers. Highly efficient methods of modeling neural recordings quantified the large impact that tissue properties, conduction distance, and nerve fiber parameters have on CNAPs. These methods expand the computational accessibility of neural recording models, enable efficient model tuning for validation, and facilitate the design of novel recording interfaces for neurostimulation feedback and understanding physiological systems.

Elephant Trunk Inspired Multimodal Deformations and Movements of Soft Robotic Arms

AbstractElephant trunks are capable of complex, multimodal deformations, allowing them to perform task‐oriented high‐degree‐of‐freedom (DOF) movements pertinent to the field of soft actuators. Despite recent advances, most soft actuators can only achieve one or two deformation modes, limiting their motion range and applications. Inspired by the elephant trunk musculature, a liquid crystal elastomer (LCE)‐based multi‐fiber design strategy is proposed for soft robotic arms in which a discrete number of artificial muscle fibers can be selectively actuated, achieving multimodal deformations and transitions between modes for continuous movements. Through experiments, finite element analysis (FEA), and a theoretical model, the influence of LCE fiber design on the achievable deformations, movements, and reachability of trunk‐inspired robotic arms is studied. Fiber geometry is parametrically investigated for 2‐fiber robotic arms and the tilting and bending of these arms is characterized. A 3‐fiber robotic arm is additionally studied with a simplified fiber arrangement analogous to that of an actual elephant trunk. The remarkably broad range of deformations and the reachability of the arm are discussed, alongside transitions between deformation modes for functional movements. It is anticipated that this design and actuation strategy will serve as a robust method to realize high‐DOF soft actuators for various engineering applications.