Fiber Bundles Research Articles

High-performance chalcogenide fiber bundle for mid-wave infrared imaging

Flexible infrared image fiber bundles (FBs) are capable of delivering thermal images of areas that are difficult for ordinary thermal cameras to access while making the imaging systems compact and lightweight. Thus, FB-based thermal imaging systems show great potential in some important applications, such as infrared endoscopy, aircraft infrared warning, and satellite remote sensing. In most applications, FBs are required to have high overall transmittance (OT) and high spatial resolution (R), but the fabrication of such high-performance FBs is still a challenge. In this work, we demonstrate a new design of flexible mid-wave infrared chalcogenide FB with high OT and decent R by optimizing the composition of glass cladding and geometric parameters of single fibers. The FB is fabricated by a modified approach combining the stack-and-draw technique and layer-stacking method, and the thermal image delivery performance of the FB is comprehensively characterized. It is shown that the core diameter (dcore) and core/cladding diameter ratio (Rcc) of single fibers can be balanced to reduce leakage of the light propagating in the single fibers while making the FB retain a reasonably high filling factor. Thus a high-performance FB can be achieved. The fabricated FB consists of 124,200 single fibers featuring an As40S60 core, an As38.9S61.1 cladding, and a polyetherimide (PEI) protective coating, with a dcore of ∼22.8 µm and an Rcc of 0.8. It has a length of ∼52 cm and a filling factor of ∼50.2%. The FB presents excellent thermal image delivery performance, including an OT of 40.5%, a single-fiber loss of 1.71 dB/m at 4.6 µm, and an R of 20.2 lp/mm, which compares favorably to previously reported FBs. These findings provide new insights for the development of high-performance thermal imaging FBs and lay a foundation for their practical applications.

Optimizing core yarn twist levels for enhanced mechanical properties of aramid-wrapped yarns and fabrics

This study addresses the issue of low surface energy of aramid fibers and their fabrics and aims to enhance their mechanical properties including tensile strength and impact resistance. Using the hollow spindle spinning method, aramid fiber bundles are employed as the core yarns with varying twist levels and nylon fibers are used as the wrapping yarns to create the nylon/aramid-wrapped yarns, which are then woven into the nylon/aramid fabrics. The investigation focuses on the effect of core yarn twist levels on the mechanical properties of the yarns and fabrics. Experimental results reveal that applying an appropriate core yarn twist can significantly improve the mechanical properties of the yarns and fabrics. Specifically, with the optimized the core yarn twist of 80 turns per meter (tpm) the tensile and hook strengths of the wrapped yarns reach 3.3 GPa and 1.2 N/Tex, respectively which are about 20.6% and 21.7% increase as compared to the untwisted yarns. Similarly, the plain-woven fabric consisting of the 80 tpm yarns achieves a tensile strength of 2577.9 N/cm, a pull-out force of 160.2 N, and an absorbed energy per unit volume of 436.5 KJ/m3 which are about 20.0%, 31.4% and 30.1% improvement, respectively as compared to the fabrics with the untwisted yarns. Additionally, the optimized fabric presents a 28.4% increase in the energy absorption efficiency and significant enhancement in abrasion resistance. These findings offer valuable insights for the potential applications of the nylon/aramid-wrapped yarns for developing personal protective fabrics and products.

White Matter Fiber Bundle Alterations Correlate with Gait and Cognitive Impairments in Parkinson's Disease based on HARDI Data.

The neuroanatomical basis of white matter fiber tracts in gait impairments in individuals suffering from Parkinson's Disease (PD) is unclear. Twenty-four individuals living with PD and 29 Healthy Controls (HCs) were included. For each participant, two-shell High Angular Resolution Diffusion Imaging (HARDI) and high-resolution 3D structural images were acquired using the 3T MRI. Diffusion-weighted data preprocessing was performed using the orientation distribution function to trace the main fiber tracts in PD individuals. Clinical characteristics between the two groups were compared, and the correlation between the FA value and behavioral data was analyzed. Quantitative gait and clinical parameters were recorded in PD at ON and OFF states, respectively. The mean tract-specific FA values of the right Cingulum Cingulate (rCC) were statistically different between the PD group and the HC group (p =0.047). The FA value of 34-58 equidistant nodes in rCC was positively correlated with Mini-Mental State Examination (MMSE) (r=0.527, p=0.024), Berg Balance Scale (BBS)-OFF (r=0.480, p =0.040), and BBS-ON (r=0.528, p =0.024) scores, while it was negatively correlated with the MDS-UPDRS-III-ON score (r=-0.502, p =0.030). Regarding the gait analysis, the FA value was significantly correlated with velocity, cadence, and stride time of the pace and rhythm domains in both 'ON' and 'OFF' states, respectively (p<0.05). This study served as an initial exploration to establish that HARDI sequences could be employed as a robust tool for analyzing microstructural alterations in white matter fiber bundles among PD patients, although the sample size was small. We confirmed microstructural integrity impairment of rCC to be significantly associated with both gait and cognitive deficits in patients with PD. Early detection of microstructural changes in rCC and targeted treatment can help improve behavioral disorders. In the future, we intend to further integrate multimodal data with assessments of patient behavior both prior to and following intervention. We will validate our findings within an independent cohort to monitor disease progression and evaluate the efficacy of therapeutic interventions.

Relating gauge gravity to string theory through obstruction

Abstract In this article we provide a more detailed account of the geometry and topology of the composite bundle formalism introduced by Tresguerres in Phys. Rev.&amp;#xD;D 66 (2002) 064025~\cite{Tresguerres2002} to accommodate gravitation as a gauge theory. In the first half of the article we identify a global structure required by the composite construction which not only exposes how the ordinary frame and tangent bundle expected in general relativity arise but provides the link or connection between these ordinary bundles and the gauge bundles of the composite bundle construction. In the second half of the article we discuss implications of this method of constructing gravity as a fiber bundle for the global structure of spacetime. We find that the underlying manifold of the composite bundle construction is expected to admit, not only a spin structure but also a string structure. As a consequence of our work we are able to extend past work on global structures of physically reasonable spacetime manifolds. It has been shown that in four spacetime dimensions, that if an oriented, Lorentzian, four dimensional manifold is stably casual that it is parallizable, and hence admits a spin structure which allows for chiral spinors. We may now add to this that such a manifold also admits a string structure.

High-Performance Optical Fiber Displacement Sensor with Extended Linear Range and Sensitivity

Optical Fiber Displacement Sensors (OFDSs) provide several advantages over conventional sensors, including their compact size, flexibility, and immunity to electromagnetic interference. These features make OFDSs ideal for use in confined spaces, such as turbines, where direct laser access is impossible. A critical aspect of OFDS performance is the geometry of the fiber bundle, which influences key parameters such as sensitivity, range, and dead zones. In this work, we present a streamlined design methodology for azimuthally symmetric OFDSs to improve the linear range of these sensors. The most effective configuration we propose is the pentafurcated bundle, which consists of a central transmitting fiber surrounded by four concentric rings of fibers with different radii. Our experimental results show that the pentafurcated designs increase both the range—up to 10.5 mm—and the sensitivity of the sensor—2mm−1—while minimizing the dead zone of the sensor (2.5 mm), allowing accurate measurements even at very short distances

Correspondence between Euler charges and nodal-line topology in Euler semimetals.

Real multi-bandgap systems have non-abelian topological charges, with Euler semimetals being a prominent example characterized by real triple degeneracies (RTDs) in momentum space. These RTDs serve as "Weyl points" for real topological phases. Despite theoretical interest, experimental observations of RTDs have been lacking, and studies mainly focus on individual RTDs. Here, we experimentally demonstrate physical systems with multiple RTDs in crystals, analyzing the distribution of Euler charges and their global connectivity. Through Euler curvature fields, we reveal that type I RTDs have quantized point Euler charges, while type II RTDs show continuously distributed Euler charges along nodal lines. We discover a correspondence between the Euler number of RTDs and the abelian/non-abelian topological charges of nodal lines, extending the Poincaré-Hopf index theorem to Bloch fiber bundles and ensuring nodal line connectivity. In addition, we propose a "no-go" theorem for RTD systems, mandating the balance of positive and negative Euler charges within the Brillouin zone.

Enhanced numerical models for two-component fluid flow in multiscale porous structures

Multi-component fluid flow simulations in multiscale porous structures, many parts of which are likely to be under-resolved at practical resolution, often require a high-fidelity numerical model to account for the contribution of under-resolved structures to the fluid flow. In previous studies, a numerical model was proposed for viscous and capillary forces from under-resolved regions. It successfully showed comparable results in absolute permeability, capillary pressure, and relative permeability when compared to an equivalent fully resolved case up to ten times higher resolution. In this study, we show further extensions of the model to handle various types of structures and to capture detailed fluid behavior. First, we introduce the controllability of surface tension in the pseudo-potential lattice Boltzmann model while keeping the interface thickness and the spurious current at the same level. This helps to resolve more detailed interface dynamics in under-resolved regions. Second, we develop a numerical model to capture the residual fluid component in the under-resolved structure. Since it is difficult to capture such cell-sized or less-than-cell-sized fluid components with diffusive interface models, we try to consider them separately using local constitutive relations, such as the absolute and relative permeability and capillary pressure curves. Third, we introduce a tensorial resistivity model to handle under-resolved heterogeneous structures, such as a fiber bundle. After calculating the principal axis for resistivity using the Hessian and the gradient of the local porosity field, the tensorial resistivity is rotated in the proper direction. Through a series of benchmark test cases, including cases using practical rock geometries, these enhancements are validated and show significant accuracy improvements with respect to the transient interface dynamics, capture of local irreducible fluid components, and directionality effects of under-resolved structures.

Surface Damage Mechanism and modes in single abrasive grinding Twill carbon fiber-reinforced-polymer laminates Basing on Stress Field Analysis

The scratch 2D twill carbon fiber-reinforced-polymer (CFRP) removal and surface evolution mechanism was studied with single abrasive scratch experiments, and the single abrasive scratch finite element model (FEM) was constructed considering progressive damage models. The surfaces evolution mechanism are revealed by FEM stress field analysis and by scanning electron microscope (SEM) images. There is weft -warp fiber woven coupling structure inside 2D twill CFRP, in this paper, woven structure coupling effect means the impedance force fields are formed by the other adjacent carbon fibers during single abrasive scratching weft or warp fibers inside CFRP. The FEM stress fields for the fiber bundles, interfaces and matrices can be analyzed, and provide an effective way to study scratch damage mechanism. Scratch damage mode for weft-containing CFRP starts with resin matrix cracks under low stress as the main feature, gradually transits to carbon fiber pull-out due to stress above interface strengthen and matrix cracks as the main features, and the damage modes finally characterize with weft carbon fibers breakage due to stress above carbon fiber shear fracture strength, fiber pull-out and matrix breakage as the main features. Scratches damage mode for warp-containing starts with the resin matrix breakage, woven structure coupling effect results in fibers stress above the tensile strength, and scratches damage mode transits to the warp fibers pull-out damage and warp carbon fibers breakage as the main features. By comparing the FEM to experimental results for scratch force and SEM, the FE model proves to be valid and accuracy.

ASSEMBLY COUPLING TECHNOLOGY OF MICROLENS ARRAY AND OPTICAL FIBER BUNDLE

Continuous improvements in high-resolution infrared remote sensing imaging technology have led to important applications in various fields; however, the low filling rate of optical fiber and degradation of the focal ratio of the image end remain problems that restrict further development. The coupling technology of the microlens array and optical fiber bundle assembly is the key to solving these problems. In this work, we studied the coupling technology of microlens array and optical fiber bundle assembly. Specifically, six degrees-of-freedom coupling assembly and infrared radiation energy measurement subsystems were built, and based on this a high-precision mechanical alignment coupling efficiency measurement system was designed. After kinematic analysis, it was found that the maximum positioning error was within the allowable error range, making the system suitable for the requirements of precision assembly. Finally, the alignment coupling efficiency of the system was tested, and the results showed that the coupling efficiency reached 92.65&amp;#37;, which was only 6.01&amp;#37; lower than the assumed theoretical value and affirmed the feasibility of the system design for improving the performance of optical fiber image transmission systems.

Coal–Rock Catastrophic Collapse: Precursors Based on AE and Fiber Bundle Models

Coal–Rock Catastrophic Collapse: Precursors Based on AE and Fiber Bundle Models

Histochemical analysis of osteoclast and osteoblast distributions on hydroxyapatite/collagen bone-like nanocomposite embedded in rat tibiae.

Hydroxyapatite (HAp)/collagen (Col) cylinders with laminated collagen layers were implanted into the tibial diaphysis of rats and examined histochemically to clarify how the orientation of HAp and Col bone-like nanocomposite fibers in HAp/Col blocks affects bone resorption and formation. HAp/Col fibers were synthesized and compressed into cylindrical blocks to mimic bone nanostructures. These were implanted into the cortical bone cavities of 10-week-old male Wistar rats with fiber bundles parallel to the tibial surface. The implants were histologically analyzed at 3, 5, 7, 14, and 28 days after implantation. TRAP-positive osteoclasts appeared after 3-5 days in the lateral region of the graft, where the fiber ends were exposed, but not in the bottom region, where the HAp/Col fibers were parallel to the surface. Osteoclasts were observed in both regions by day 14. PHOSPHO1-positive osteoblasts were first detected on day 5, appearing slightly away from the cylinder laterally but directly on the bottom surface. A few osteoblasts contacted the block laterally, whereas many were observed on the new bone tissue at the bottom, between days 7 and 14. Bone formation was induced earlier in the bottom region, whereas lateral resorption was dominant. This suggested the uncoupling of bone resorption and formation in the early postimplantation stages. However, bone remodeling shifted to coupling between osteoclasts and osteoblasts throughout the cylinder by day 28. The orientation of HAp/Col fibers in HAp/Col graft materials substantially affected the preferential induction of bone resorption or formation during the early stages of bone regeneration.

Striated muscle fiber crossings of the head and neck: a histological study using near-term human fetuses and elderly cadavers.

Striated muscle fiber crossings at almost right angle are known to exist in the face, soft palate, pharyngeal wall and tongue. We aimed to identify a specific interface tissue at the crossing. We observed histological sections from 22 half-heads of 12 near-term fetuses at 26-40 weeks (crown-rump length, 215-334 mm). For comparison, we also observed tongue frontal sections from 5 elderly cadavers (75-85 years old). At the angle of mouth as well as in the soft palate and pharyngeal wall, a solitary striated muscle fiber (e.g., levator) consistently crossed a fiber bundle of the antagonist muscle (e.g., depressor), but a solitary-to-solitary fiber interdigitation was unlikely with the antagonist muscle. Near the external nasal orifice as well as in the tongue intrinsic muscle layer, at every section, there was a crossing with an endomysium-to-endomysium contact: the nasalis and platysma muscles and; the vertical and transverse (or inferior longitudinal) tongue muscles. Therein, the functional vectors crossed at almost right angle. Also in adult tongue, the vertical and transverse muscle fibers sometimes (0-2 sites per section) crossed with an endomysium-to-endomysium contact. At the muscle crossing with an endomysium contact, the endomysium and basement membrane seemed to receive a friction stress between two muscles. Although some crossings might disappear due to high muscle activity after birth, not a few of them were likely to maintain. To minimize the mechanical stress, a minute nervous control of the timing, duration and strength of muscle contraction seemed to be necessary.

Research on the Earth Reflected Solar Spectral Radiation Observation System Based on the Lagrange L1 Point of the Earth–Moon System

We propose an observation system based on the Lagrange L1 point of the Earth–Moon system to observe solar spectral radiation reflected from the Earth, enabling continuous hyperspectral observation of the Earth’s hemisphere. The system can observe the solar spectral radiation reflected by the Moon, with its data applicable to on-orbit spectral radiation calibration. In this paper, the spectral irradiance at the entrance pupil of the Earth spectral radiation observation system (ESROS) is analyzed, and the optical design of the ESROS is introduced. An off-axis two-mirror telescope system, a coupling system of a microlens array and a fiber bundle, and an optical splitting system based on concave grating are used to achieve the full field of view hyperspectral splitting and miniaturization of the instrument. Finally, the stray radiation suppression of the instrument is introduced. The results show that the spectral resolution of the system is better than 5 nm in the 380–1000 nm band, and the spectral resolution is better than 10 nm in the 1000–1700 nm band. When observing the Earth, the signal-to-noise ratio is greater than 200. The external stray radiation suppression reaches the order of 10−9. The ESROS will provide crucial data support for researching global energy balance, climate change, and the spectral characteristics of exoplanets, facilitating planetary science and the exploration of extraterrestrial life.

Histological Study of Skin Structures From Selected Body Areas in the Varanus komodoensis.

The skin of the Komodo dragon (Varanus komodoensis) is covered by a form of armour formed mainly of scales, which often co-occur with osteoderms. Scales are keratinized, non-mineralized structures in the uppermost layer of the epidermis that are in contact with each other to form a system in which individual scales are isolated from each other by a softer skin fold zone. In the Varanus, the surface of the scales is flat and smooth (thoracic limb, abdomen, and tail areas), domed and smooth (head area) or domed with conical ornamentation (dorsal surface, pelvic limb-dorsal surface areas). In contrast, osteoderms are mineralized structures that are an integral part of the skin, located below the epidermal surface and positioned parallel (head, tail, thoracic limb-dorsal surface, thoracic limb-palmar surface, and tail) or obliquely (pelvic limb-dorsal surface, groin, abdomen) to the surface. Regardless of the body region, osteoderms are structures that are completely anchored in the dermis, and their surface is smooth and devoid of ornamentation. Tangential sections of the osteoderms demonstrate concentric resting lines. Histological sections of the varanid dermis show the presence of collagen bundles, parallel interlacing or crossing bundles of collagen fibers of varying thickness and degree of compactness, accompanied by muscle fibers. In the area of skin close to the osteoderm, loosely arranged bundles of collagen fibers are present, while in the zone distal to the osteoderm, a compact arrangement of these fibers is present. This study documents the morphological diversity and distribution of osteoderms and scales in selected areas of the body of V. komodoensis. Scales are characterized by a high polymorphism related to body region, while osteoderms show a high morphological similarity independent of the area of occurrence.

Anatomical and Physicochemical Attributes of Endemic Medicinal Plant Species Vincetoxicum capparidifolium (Wight &amp; Arn.) Kuntze, Apocynaceae

ABSTRACTVincetoxicum capparidifolium (Wight &amp; Arn.) Kuntze [=Tylophora capparidifolia (Wight &amp; Arn.) Kuntze], belonging to the family Apocynaceae, is a medicinal plant species endemic to the southern Western Ghats, Tamil Nadu, India. The current study sought to investigate the macroscopic, organoleptic, microscopic, physicochemical, and proximate compositional aspects of the fresh and powdered leaf and stem portions of V. capparidifolium. The anatomical peculiarities of the leaf parts reveal a hypostomatic nature with paracytic stomata, the epidermis being made up of thin‐walled cells covered with a thick cuticle (5.9 μm), and the hypodermis comprising angular collenchyma cells. The petiole is oval/rounded‐ellipse with abundant nonglandular multicellular trichomes ascending from the epidermis. The hypodermis is composed of collenchymatous cells containing many calcium oxalate crystals and silica bodies. Bicollateral vascular bundles with internal and external phloem characterize the leaf, stem, and petiole parts. The stem is covered by a thin cuticle, chlorenchymatous hypodermis, and large gelatinous fiber bundles (124.29 × 81.71 μm). Secondary growth in the stem is characterized by the development of periderm and lignified vascular tissues. Bicollateral vascular bundles are overlaid by irregular sclerenchyma patches (7.07 × 5.36 μm), a parenchymatous cortex, and pith composed of thin‐walled parenchyma cells. Scanning electron microscopic study of powdered plant parts disclosed the presence of fiber in the stem and a trace outline of leaf epidermal cells. X‐ray diffraction analysis specified indefinite crystallinity in the plant powder (57.038–69.500 nm). Thorough examination of pH, ash content, and percentage of crude lipid confirms that V. capparidifolium exhibits sufficient quality and purity.

Mechanically recycled textile fibers in carded and needle-punched non-wovens: Implications on processability, structure, and performance

To foster a circular economy, it is crucial to increase the recycling of solid waste significantly, particularly post-consumer textile waste, and identify viable applications for the reclaimed materials. This study specifically examined the integration of mechanically recycled post-consumer polyester and cotton fibers containing fractions into carded and needle-punched non-woven structures. The research investigated the carding processability of four mechanically recycled fibers, examining their performance when combined with virgin polyester fibers in varying ratios. The fiber fractions were characterized in terms of mean fiber length, short fiber content, fiber uniformity, diameter, fiber bundle strength, and elongation. The processability challenges encountered during the carding of the mechanically recycled textile fractions were mainly associated with high proportions of synthetic recycled fibers, which resulted in increased fiber piling on the metallic parts of the carding device. Furthermore, the effect of different blend ratios of mechanically recycled polyester and cotton fibers with virgin polyester fiber on the properties of carded and needle-punched structures, including mass per unit area, thickness, tensile strength, elongation, air permeability, morphology, and porosity was studied. The tensile properties and air permeability of non-wovens obtained from 50/50 blends of recycled polyester cotton and virgin polyester were comparable to those produced from 100% virgin polyester fibers. The results of this study demonstrate that carding and needle punching provide a robust route for processing polyester and cotton containing mechanically recycled end-of-life textile-based fractions without the use of chemical additives.

Influence of Different Fibers on Performance of Bitumen Binders and Thin-Overlay Bitumen Mixtures

Thin-layer covers easily crack under traffic load, shortening their service life. Incorporating fiber materials into the mix can enhance crack resistance thanks to their abundance, affordability, and flexibility. However, different types of fibers have different performances in bitumen and mixtures due to different material properties. To explore this problem, basalt fiber, polypropylene fiber, and glass fiber were selected in this paper. The surface characteristics, internal structure, and adsorption capacity of oily substances were observed via scanning electron microscopy and oil absorption rate testing. The effects of fibers on the high-temperature and low-temperature properties of styrene-butadiene-styrene block copolymer-modified bitumen were investigated using the dynamic shear rheometer and the force ductility method. Ultimately, through indirect tensile testing and semi-circular bending tests, and the introduction of the toughness index and fracture toughness, a comprehensive evaluation was conducted on how varying fiber types and content affect the crack resistance and toughness of bitumen mixtures. The results show that the density and dispersion of the bundle fibers are the key to the oil absorption capacity under similar internal and external structural conditions. The oil absorption rate of polypropylene fiber is the best, reaching 5.423. Fiber incorporation can significantly improve the high-temperature rheological properties of bitumen. At 4% dosage, G*/sinδ increased by about 107.04% on average at 76 °C. At low temperatures, the increase in fiber content leads to a decrease in bitumen elasticity, and the influence of glass fiber is more obvious. The area of toughness did not reach 2000 N·mm at 4% dosage. After adding fibers, the toughness index and fracture toughness of the mixture increased by more than 2% and 35%, respectively. The maximum increases in fracture energy and crack initiation energy of the mixture are 14.29% and 47.29%, respectively. It shows that the fiber enhances the toughness, crack resistance, and crack propagation resistance of the mixture. The research results can provide some reference for the application of fiber-reinforced bitumen mixtures.

Automated White Matter Fiber Tract Segmentation for the Brainstem

ABSTRACTThis study aimed to develop an automatic segmentation method for brainstem fiber bundles. We utilized the brainstem as a seed region for probabilistic tractography based on multishell, multitissue constrained spherical deconvolution in 40 subjects from the Human Connectome Project (HCP). All tractography data were registered into a common space to construct a brainstem fiber cluster atlas. A total of 100 fiber clusters were identified and annotated. Cortical parcellation–based fiber selection was then performed to extract fibers within the annotated clusters that projected to their corresponding cortical regions. This atlas was applied for automatic brainstem fiber bundle segmentation in 10 HCP subjects and 8 patients with brainstem cavernous malformations. The spatial overlap between automatic and manual reconstruction was assessed. Ultimately, eight fiber bundles were identified in the brainstem atlas on the basis of their trajectories: the corticospinal tract (CST), corticobulbar tract, frontopontine tract, parieto‐occipital‐pontine tract, medial lemniscus, and superior, middle, and inferior cerebellar peduncles. The mean and standard deviation of the weighted dice (wDice) scores between the automatic and manual reconstructions were 0.9076 ± 0.0950 for the affected CST, 0.9388 ± 0.0439 for the contralateral CST, 0.9130 ± 0.0588 for the affected medial lemniscus, and 0.9600 ± 0.0243 for the contralateral medial lemniscus. This proposed method effectively distinguishes major brainstem fiber bundles across subjects while reducing labor costs and interoperator variability inherent to manual reconstruction. Additionally, this method is robust in that it allows for the visualization and identification of fiber tracts surrounding brainstem cavernous malformations.

Flexible Fiber Sensors for Real-Time Monitoring of Redox Signaling Molecules in Exercise-Mimicking Engineered Skeletal Muscle.

Real-time monitoring of reactive oxygen and nitrogen species (RONS) in skeletal muscle provides crucial insights into the cause-and-effect relationships between physical activity and health benefits. However, the dynamic production of exercise-induced RONS remains poorly explored, due to the lack of sensing tools that can conform to soft skeletal muscle while monitor RONS release during exercise. Here we introduce dual flexible sensors via twisting carbon nanotubes into helical bundles of fibers and subsequent assembling electrochemical sensing components. These flexible sensors exhibit low bending stiffness, excellent H2O2 and NO sensing abilities, outstanding biocompatibility and compliance with engineered skeletal muscle tissue. This allows real-time and simultaneous monitoring of H2O2 and NO release from engineered skeletal muscle in response to different exercise-mimicking stretches, which reveals that warm-up activities before high-intensity exercise may enhance adaptive responses by down-regulating H2O2 and up-regulating NO production. The proposed sensing strategy demonstrates great versatility in monitoring multiple biomarkers of soft tissue and organs.

Flexible Fiber Sensors for Real‐Time Monitoring of Redox Signaling Molecules in Exercise‐Mimicking Engineered Skeletal Muscle

Real‐time monitoring of reactive oxygen and nitrogen species (RONS) in skeletal muscle provides crucial insights into the cause‐and‐effect relationships between physical activity and health benefits. However, the dynamic production of exercise‐induced RONS remains poorly explored, due to the lack of sensing tools that can conform to soft skeletal muscle while monitor RONS release during exercise. Here we introduce dual flexible sensors via twisting carbon nanotubes into helical bundles of fibers and subsequent assembling electrochemical sensing components. These flexible sensors exhibit low bending stiffness, excellent H2O2 and NO sensing abilities, outstanding biocompatibility and compliance with engineered skeletal muscle tissue. This allows real‐time and simultaneous monitoring of H2O2 and NO release from engineered skeletal muscle in response to different exercise‐mimicking stretches, which reveals that warm‐up activities before high‐intensity exercise may enhance adaptive responses by down‐regulating H2O2 and up‐regulating NO production. The proposed sensing strategy demonstrates great versatility in monitoring multiple biomarkers of soft tissue and organs.