Multifunctional Magnetic Muscles for Soft Robotics.

Despite recent advancements, artificial muscles have not yet been able to strike the right balance between exceptional mechanical properties and dexterous actuation abilities that are found in biological systems. Here, we present an artificial magnetic muscle that exhibits multiple remarkable mechanical properties and demonstrates comprehensive actuating performance, surpassing those of biological muscles. This artificial muscle utilizes a composite configuration, integrating a phase-change polymer and ferromagnetic particles, enabling active control over mechanical properties and complex actuating motions through remote laser heating and magnetic field manipulation. Consequently, the magnetic composite muscle can dynamically adjust its stiffness as needed, achieving a switching ratio exceeding 2.7 × 10³. This remarkable adaptability facilitates substantial load-bearing capacity, with specific load capacities of up to 1000 and 3690 for tensile and compressive stresses, respectively. Moreover, it demonstrates reversible extension, contraction, bending, and twisting, with stretchability exceeding 800%. We leverage these distinctive attributes to showcase the versatility of this composite muscle as a soft continuum robotic manipulator. It adeptly executes various programmable responses and performs complex tasks while minimizing mechanical vibrations. Furthermore, we demonstrate that this composite muscle excels across multiple mechanical and actuation aspects compared to existing actuators.

Ortho-positronium lifetime for soft-tissue classification.

The objective of this work is to showcase the ortho-positronium lifetime as a probe for soft-tissue characterization. We employed positron annihilation lifetime spectroscopy to experimentally measure the three components of the positron annihilation lifetime-para-positronium (p-Ps), positron, and ortho-positronium (o-Ps)-for three types of porcine, non-fixated soft tissues ex vivo: adipose, hepatic, and muscle. Then, we benchmarked our measurements with X-ray phase-contrast imaging, which is the current state-of-the-art for soft-tissue analysis. We found that the o-Ps lifetime in adipose tissues (2.54 ± 0.12 ns) was approximately 20% longer than in hepatic (2.04 ± 0.09 ns) and muscle (2.03 ± 0.12 ns) tissues. In addition, the separation between the measurements for adipose tissue and the other tissues was better from o-Ps lifetime measurement than from X-ray phase-contrast imaging. This experimental study proved that the o-Ps lifetime is a viable non-invasive probe for characterizing and classifying the different soft tissues. Specifically, o-Ps lifetime as a soft-tissue characterization probe had a strong sensitivity to the lipid content that can be potentially implemented in commercial positron emission tomography scanners that feature list-mode data acquisition.

Achieving optical transparency in live animals with absorbing molecules.

Optical imaging plays a central role in biology and medicine but is hindered by light scattering in live tissue. We report the counterintuitive observation that strongly absorbing molecules can achieve optical transparency in live animals. We explored the physics behind this observation and found that when strongly absorbing molecules dissolve in water, they can modify the refractive index of the aqueous medium through the Kramers-Kronig relations to match that of high-index tissue components such as lipids. We have demonstrated that our straightforward approach can reversibly render a live mouse body transparent to allow visualization of a wide range of deep-seated structures and activities. This work suggests that the search for high-performance optical clearing agents should focus on strongly absorbing molecules.

The role of miR-216a-mediated Nrf2 pathway in muscle oxidative stress of Siniperca chuatsi induced by cadmium.

Cadmium (Cd) is a toxic heavy metal pollutant in the environment. Excessive Cd in water has toxic effects on fish, endangering their healthy growth and ultimately affecting the quality and safety of aquatic products. To evaluate the toxicity of excessive Cd to fish through potential oxidative damage, Siniperca chuatsi was exposed to Cd in water for 15 days. It was found that Cd exposure significantly decreased the survival rate of S. chuatsi and Cd was detected in their muscle. Meanwhile, Cd disrupts the redox balance by reducing antioxidant enzyme activities, increasing reactive oxygen species (ROS) and malondialdehyde (MDA) levels in muscle, and promoting oxidative damage. Histomorphology showed that enlargement of muscle fiber gaps, cell swelling and vacuolar degeneration after Cd exposure. In addition, Cd toxicity induced up-regulating the expression of miR-216a, while down-regulation of Nrf2 protein and its downstream antioxidant enzyme genes expression. Further analysis revealed that miR-216a was significantly negatively correlated with the expression of Nrf2, and injection of miR-216a antagomir significantly enhanced the expression of Nrf2 and antioxidant enzyme genes, as well as the activity of antioxidant enzymes, thereby reducing the damage of Cd to fish. These results suggested that miR-216a-mediated Nrf2 signaling pathway plays an important role in Cd-induced oxidative stress of S. chuatsi muscle.

Status of trace metals and arsenic in sediments and catfish muscles (Clarias gariepinus) from the Eastern Tanzanian basin.

Trace metals and metalloids are groups of chemical elements that naturally occur in low concentrations and cycle in the environment driven by natural processes and human activities. They have a persistent and bio-accumulative tendency in the environment, and certain trace metals and metalloids have become a public health concern. This study assesses the concentration of eleven trace metals and a metalloid in sediments and catfish muscle from five study sites in the Eastern Tanzanian River basin. Forty catfish tissues and fifteen sediment samples were collected and analyzed using ICP-MS. Concentrations of As, Cd, Co, Pb, and Zn did not exceed the United States Environmental Protection Agency (USEPA) guideline for pollution of sediments, while Al Cr, Al, Mn, and V with values ranging from (118.54 to 70154.55) indicating moderately polluted. The stations Java-Sadaani and Matandu showed the highest Cr, Ni, and Cu concentrations, but the potential ecological risk index (RI) was low (RI < 95). In the catfish muscle tissue, the levels of Cd, Pb, Cu, and Zn did not surpass the EU and FAO/WHO limits and results ranged from 2.22 to 35.22mg/kg. Low levels of accumulation of Cd, Pb, and As were found in this study compared to catfish muscles from other studies, whereas the concentrations of other trace metals and metalloids analyzed had comparable results. Biota/sediment accumulation factors (BSAF) were all < 1. The weekly metal intake (MWI) results ranged from 6.89E-04 to 2.43E+01 µg/know-1week-1, indicating a low risk as the value did not exceed the FAO/WHO established Permissible Tolerable Weekly Intake (PTWI). The non-carcinogenic health risk result THQ was 4.43E-02 and the carcinogenic health risks result HI was 4.42E-05 which indicated tolerable levels of risks as both the values of the Target Hazard Quotient (THQ) and the Hazard Index (HI) was < 1, and the carcinogenic target risk (TR) is < 0.0001. The highest TR values were observed for Cr and Ni. We recommend a continued monitoring of the changes in trace metal levels in the environment and biota together with continuous public health education on the dangers of high levels of trace metals.

Impact of Selected Glucagon-like Peptide-1 Receptor Agonists on Serum Lipids, Adipose Tissue, and Muscle Metabolism-A Narrative Review.

Glucagon-like peptide-1 receptor agonists (GLP-1 RA) are novel antihyperglycemic agents. By acting through the central nervous system, they increase satiety and reduce food intake, thus lowering body weight. Furthermore, they increase the secretion of insulin while decreasing the production of glucagon. However, recent studies suggest a more complex metabolic impact through the interaction with various other tissues. In our present review, we aim to provide a summary of the effects of GLP-1 RA on serum lipids, adipose tissue, and muscle metabolism. It has been found that GLP-1 RA therapy is associated with decreased serum cholesterol levels. Epicardial adipose tissue thickness, hepatic lipid droplets, and visceral fat volume were reduced in obese patients with cardiovascular disease. GLP-1 RA therapy decreased the level of proinflammatory adipokines and reduced the expression of inflammatory genes. They have been found to reduce endoplasmic reticulum stress in adipocytes, leading to better adipocyte function and metabolism. Furthermore, GLP-1 RA therapy increased microvascular blood flow in muscle tissue, resulting in increased myocyte metabolism. They inhibited muscle atrophy and increased muscle mass and function. It was also observed that the levels of muscle-derived inflammatory cytokines decreased, and insulin sensitivity increased, resulting in improved metabolism. However, some clinical trials have been conducted on a very small number of patients, which limits the strength of these observations.

Differential tissue distribution of pharmaceuticals in a wild subtropical marine fish.

To date, the presence of pharmaceuticals has been extensively documented across a wide range of aquatic systems and biota. Further, substantial progress has been made in transitioning from laboratory assessments of pharmaceutical fate and effects in fish to in situ assessments of exposure and effects; however, certain research areas remain understudied. Among these is investigation of differential accumulation across multiple internal tissues in wild marine fish beyond the species commonly sampled in laboratory and freshwater field settings. This study examined the presence of pharmaceuticals across four tissues (plasma, muscle, brain, and liver) in a wild marine fish, bonefish (Albula vulpes), throughout coastal South Florida, USA. Differential accumulation across tissues was assessed for the number and concentration, identity, and composition of accumulated pharmaceuticals by sampling 25 bonefish and analyzing them for 91 pharmaceuticals. The concentration of pharmaceuticals was highest in plasma > liver > brain > muscle, while the number of pharmaceuticals was highest in liver > brain > plasma > muscle. The identity of detected pharmaceuticals was tissue specific, and there was an inverse relationship between the number of detections for each pharmaceutical and its log Kow. The composition of pharmaceuticals was tissue specific for both pharmaceutical presence/absence and concentration. Across all tissues, the greatest similarity was between brain and liver, which were more similar to plasma than to muscle, and muscle was the most distinct tissue. For tissue compositional variability, muscle was the most diverse in accumulated pharmaceuticals, while plasma, brain, and liver were similarly variable. With the highest concentrations in plasma and highest number in liver, and documented variability in accumulated pharmaceuticals across tissues, our results highlight the importance of tissue selection when surveying exposure in wild fish, suggesting that multi-tissue analysis would allow for a more comprehensive assessment of exposure diversity and risk of adverse effects.

eEF1α2 is required for actin cytoskeleton homeostasis in the aging muscle.

The translation elongation factor eEF1α (eukaryotic elongation factor 1α) mediates mRNA translation by delivering aminoacyl-tRNAs to ribosomes. eEF1α also has other reported roles, including the regulation of actin dynamics. However, these distinct roles of eEF1α are often challenging to uncouple and remain poorly understood in aging metazoan tissues. The genomes of mammals and Drosophila encode two eEF1α paralogs, with eEF1α1 expressed ubiquitously and eEF1α2 expression more limited to neurons and muscle cells. Here, we report that eEF1α2 plays a unique role in maintaining myofibril homeostasis during aging in Drosophila. Specifically, we generated an eEF1α2 null allele, which was viable and showed two distinct muscle phenotypes. In young flies, the mutants had thinner myofibrils in indirect flight muscles that could be rescued by expressing eEF1α1. With aging, the muscles of the mutant flies began showing abnormal distribution of actin and myosin in muscles, but without a change in actin and myosin protein levels. This age-related phenotype could not be rescued by eEF1α1 overexpression. These findings support an unconventional role of Drosophila eEF1α2 in age-related homeostasis of muscle myofibers.

Rapid and convenient screening method based on single-chain variable fragments for the detection of restricted monensin in chicken muscle.

A colloidal gold immunochromatographic assay (CGIA) based on single-chain variable fragments (scFvs) has been successfully developed for the detection of monensin (MON). Colloidal gold probes were conjugated to anti-MON scFvs through electrostatic interaction, with the conjugated objects serving as the visual signals. The detection lines were formed by capturing the antibody with MON-OVA. This assay offers a rapid detection time of 15 min, a wide linear range from 2.19 to 10.76 ng mL-1, and boasts high accuracy, precision, and an absence of cross-reactivity. By homology modeling and molecular docking, we predicted the interaction patterns between the scFv and monensin, and the amino acid residues involved in the recognition of MON by the antibody were analyzed. These key amino acid sites are presumed integral to ligand recognition per current interaction models. This hypothesis was confirmed by computer-aided alanine scanning mutation, MM/P(G)BSA molecular dynamics simulation, and in vitro binding experiments. In this study, we successfully developed the scFvs-based CGIA system for rapid and easy quantification of monensin, providing a simple, efficient routine detection of chicken muscle samples.

Culture and Immunomodulation of Equine Muscle-Derived Mesenchymal Stromal Cells: A Comparative Study of Innovative 2D versus 3D Models Using Equine Platelet Lysate.

Muscle-derived mesenchymal stromal cells (mdMSCs) hold great promise in regenerative medicine due to their immunomodulatory properties, multipotent differentiation capacity and ease of collection. However, traditional in vitro expansion methods use fetal bovine serum (FBS) and have numerous limitations including ethical concerns, batch-to-batch variability, immunogenicity, xenogenic contamination and regulatory compliance issues. This study investigates the use of 10% equine platelet lysate (ePL) obtained by plasmapheresis as a substitute for FBS in the culture of mdMSCs in innovative 2D and 3D models. Using muscle microbiopsies as the primary cell source in both models showed promising results. Initial investigations indicated that small variations in heparin concentration in 2D cultures strongly influenced medium coagulation with an optimal proliferation observed at final heparin concentrations of 1.44 IU/mL. The two novel models investigated showed that expansion of mdMSCs is achievable. At the end of expansion, the 3D model revealed a higher total number of cells harvested (64.60 ± 5.32 million) compared to the 2D culture (57.20 ± 7.66 million). Trilineage differentiation assays confirmed the multipotency (osteoblasts, chondroblasts and adipocytes) of the mdMSCs generated in both models with no significant difference observed. Immunophenotyping confirmed the expression of the mesenchymal stem cell (MSC) markers CD-90 and CD-44, with low expression of CD-45 and MHCII markers for mdMSCs derived from the two models. The generated mdMSCs also had great immunomodulatory properties. Specific immunological extraction followed by enzymatic detection (SIEFED) analysis demonstrated that mdMSCs from both models inhibited myeloperoxidase (MPO) activity in a strong dose-dependent manner. Moreover, they were also able to reduce reactive oxygen species (ROS) activity, with mdMSCs from the 3D model showing significantly higher dose-dependent inhibition compared to the 2D model. These results highlighted for the first time the feasibility and efficacy of using 10% ePL for mdMSC expansion in novel 2D and 3D approaches and also that mdMSCs have strong immunomodulatory properties that can be exploited to advance the field of regenerative medicine and cell therapy instead of using FBS with all its drawbacks.

Optogenetic induction of mechanical muscle stress identifies myosin regulatory ubiquitin ligase NHL-1 in C. elegans.

Mechanical stress during muscle contraction is a constant threat to proteome integrity. However, there is a lack of experimental systems to identify critical proteostasis regulators under mechanical stress conditions. Here, we present the transgenic Caenorhabditis elegans model OptIMMuS (Optogenetic Induction of Mechanical Muscle Stress) to study changes in the proteostasis network associated with mechanical forces. Repeated blue light exposure of a muscle-expressed Chlamydomonas rheinhardii channelrhodopsin-2 variant results in sustained muscle contraction and mechanical stress. Using OptIMMuS, combined with proximity labeling and mass spectrometry, we identify regulators that cooperate with the myosin-directed chaperone UNC-45 in muscle proteostasis. One of these is the TRIM E3 ligase NHL-1, which interacts with UNC-45 and muscle myosin in genetic epistasis and co-immunoprecipitation experiments. We provide evidence that the ubiquitylation activity of NHL-1 regulates myosin levels and functionality under mechanical stress. In the future, OptIMMuS will help to identify muscle-specific proteostasis regulators of therapeutic relevance.

Comparative microscopic anatomy of Schizomida - 1. Segmental axial musculature and body organization.

Schizomida is an enigmatic group of arachnids that is traditionally considered the dwarfed sister to Thelyphonida. Schizomids are of interest for evolutionary morphology, because they show a number of features like a tripartite prosoma dorsal shield (pro-, meso-, metapeltidium), formation of three sterna, a complex prosoma-opisthosoma transition and a metasoma. By analyzing the body organization of Schizomida and comparing it to Thelyphonida and other arachnids, this article provides evidence for independent evolution of some of these features in Schizomida. This supports the idea that, among arachnids, multiple and independent evolutionary pathways have resulted in similar morphologies, that conventionally have been considered shared similarities. - The analysis of serial microscopic sections and µCT-imaging of segmental indicator muscles of the prosoma evidences that the propeltidium covers prosoma segments 0-4, and the metapeltidium covers segments 5 and 6. The mesopeltidium is a dorsolateral sclerotization of the pleural membrane, not assigned to a segment, and therefore not a tergite. The topographic association of segmental musculature and sclerites of the tripartite dorsum of the prosoma differs from other taxa with such external body organization, e.g., Palpigradi and Solifugae, suggesting independent evolutionary origin. - The prosoma-opisthosoma transition integrates the first opisthosoma segment into the prosoma. The sternite of the first opisthosoma segment forms the metasternum between the coxae of the fourth pair of walking legs. The morphology of the prosoma-opisthosoma transition is similar to Uropygi and Amblypygi, but is less complex. - The morphology of the metasoma (opisthosoma segments X-XII) of Schizomida and Thelyphonida differs from that of all other arachnids carrying a metasoma, thus providing support for multiple independent evolutionary origins of metasomata.

Bee morphology: A skeletomuscular anatomy of Thyreus (Hymenoptera: Apidae).

Although the knowledge of the skeletal morphology of bees has progressed enormously, a corresponding advance has not happened for the muscular system. Most of the knowledge about bee musculature was generated over 50 years ago, well before the digital revolution for anatomical imaging, including the application of microcomputed tomography. This technique, in particular, has made it possible to dissect small insects digitally, document anatomy efficiently and in detail, and visualize these data three dimensionally. In this study, we document the skeletomuscular system of a cuckoo bee, Thyreus albomaculatus and, with that, we provide a 3D atlas of bee skeletomuscular anatomy. The results obtained for Thyreus are compared with representatives of two other bee families (Andrenidae and Halictidae), to evaluate the generality of our morphological conclusions. Besides documenting 199 specific muscles in terms of origin, insertion, and structure, we update the interpretation of complex homologies in the maxillolabial complex of bee mouthparts. We also clarify the complicated 3D structure of the cephalic endoskeleton, identifying the tentorial, hypostomal, and postgenal structures and their connecting regions. We describe the anatomy of the medial elevator muscles of the head, precisely identifying their origins and insertions as well as their homologs in other groups of Hymenoptera. We reject the hypothesis that the synapomorphic propodeal triangle of Apoidea is homologous with the metapostnotum, and instead recognize that this is a modification of the third phragma. We recognize two previously undocumented metasomal muscle groups in bees, clarifying the serial skeletomusculature of the metasoma and revealing shortcomings of Snodgrass' "internal-external" terminological system for the abdomen. Finally, we elucidate the muscular structure of the sting apparatus, resolving previously unclear interpretations. The work conducted herein not only provides new insights into bee morphology but also represents a source for future phenomic research on Hymenoptera.

Role of the intestines on the muscle quality of Pacific white shrimp (Litopenaeus vannamei) during chilled storage: Physicochemical and label-free-based peptidomics analyses.

The effect of shrimp deveining on the quality of Pacific white shrimp muscle was investigated by analyzing the protein degradation during chilled storage via physicochemical and label-free peptidomics analyses. In this study, shrimp with intact intestines were in the control group (CS), while deveined shrimp (DS) were in the treatment group. The total viability count (TVC), total volatile base nitrogen (TVB-N) content, and trichloroacetic acid (TCA)-soluble peptide content in all of the shrimp groups gradually increased with prolonged chilled storage. However, in the later stages of chilled storage, the DS samples exhibited significantly lower TVB-N, total bacterial, and TCA-soluble peptide contents than the CS samples, indicating that deveining treatment effectively prolonged shrimp quality. The peptidomics analysis revealed varying degrees of protein hydrolysis in the DS and CS samples during chilled storage. A total of 396 differentially abundant peptides (DAPs) were identified in the DS compared with the CS, comprising 98 upregulated and 298 downregulated segments. This suggests that the removal of the intestine effectively inhibits protein hydrolysis. Gene ontology (GO) analysis suggested that the DAPs were mainly involved in catalytic activity, binding, and metabolic processes. The cluster of orthologous groups of protein (COG) analysis showed that the cytoskeleton dynamics of the muscle proteins underwent considerable alterations influenced by the shrimp's intestines during chilled storage.

Bone and muscle differences in children and adolescents with type 1 diabetes: The mediating role of physical activity.

Children with type 1 diabetes (T1D) experience an increased risk of fracture, which may be related to altered bone development. We aimed to assess differences in bone, muscle and physical activity (PA), and explore if better muscle and PA measures would mitigate bone differences between children and adolescents with T1D and typically developing peers (TDP). We matched 56 children and adolescents with T1D (mean age 11.9 yrs) and 56 TDP (11.5 yrs) by sex and maturity from 171 participants with T1D and 66 TDP (6-17 yrs). We assessed the distal radius and tibia with high-resolution peripheral quantitative computed tomography (HR-pQCT), and the radius and tibia shaft bone and muscle with pQCT. We also measured muscle function from force-related measures in neuromuscular performance tests (push-up, grip test, countermovement and long jump). We compared PA based on questionnaire scores and accelerometers between groups. Bone, muscle, and neuromuscular performance measures were compared using MANOVA. We used mediation to explore the role of PA and muscle in bone differences. Children and adolescents with T1D had 6-10 % lower trabecular density, bone volume fraction, thickness and number at both distal radius and tibia, and 11 % higher trabecular separation at the distal radius than TDP. They also had 3-16 % higher cortical and tissue mineral density, and cortical thickness at the distal radius, 5-7 % higher cortical density and 1-3 % higher muscle density at both shaft sites compared to TDP. PA mediated the between-group difference in trabecular number (indirect effect -0.04) at the distal radius. Children and adolescents with T1D had lower trabecular bone density and deficits in trabecular micro-architecture, but higher cortical bone density and thickness at the radius and tibia compared to TDP. They engaged in less PA but had comparable muscle measures to those of TDP. PA participation may assist in mitigating deficit in trabecular number observed in children and adolescents with T1D.

Influence of muscle soft tissue and lower limbs on the vibration behavior of the entire spine inside the seated human body: A finite element study.

The objective of the study is to investigate the vibration behavior of the entire spine inside the human body and the influence of muscle soft tissue and lower limbs on spinal response under vertical whole-body vibration. This study conducted modal and random response analyses to simulate the modal displacements and stress of all intervertebral discs in the vertical principal mode in the skeleton, upper, and whole body. Additionally, the acceleration response of intervertebral discs under vertical random excitation was investigated. The results revealed that removing muscle soft tissue and lower limbs significantly changed the resonant frequency, modal displacement, and stress. Particularly, there was a rapid increase in vertical displacement of the lumbar spine in the skeleton model. The reason for that was due to the lack of soft tissue to provide stability, leading to significant lumbar spine bending. Under random excitation, the fore-aft acceleration of intervertebral discs in the skeleton model was considerably larger than that in the whole body, especially in the lumbar spine where it can reach up to four times higher. Conversely, the vertical response of the intervertebral discs inside the human body model was 1.4-2.4 times larger than that of the skeleton model. Muscle soft tissue contributes to the strength of the spine, reducing fore-aft response. The muscle soft tissue in the gluteal region, connected below the spine, can lower the vertical natural frequency and attenuate spinal impact. Although the lower limbs enhance spinal stability, stimulation from the feet can superimpose vibrational responses in the spine.

Metal distribution in three organs and edibility assessment on Coptodon rendalli from the Umgeni River impacted by metallurgic industrial activities.

Fish is among the most affordable and readily available protein sources for communities residing near water bodies. However, the recent pollution status of aquatic ecosystems has rendered fish consumption risky for human health. The study evaluated metal levels in the liver, gill, and muscle tissues of Redbreast tilapia (Coptodon rendalli) from Inanda and Nagle dams in the uMgeni River system. Metals, Al, Sb, Cd, Cr, Fe, Mn, Mo, Pb, and Zn were analysed using ICP-OES. Fish size showed no significant difference between the two dams (p > 0.05) whereas a descending trend liver > gill > muscle was observed for most metal levels at both dams. Moreover, there was a clear separation for metal levels in the liver, gill, and muscle between the two dams (p < 0.001) and a similar trend was observed for organs in each dam (p < 0.001). No relationship was observed between fish length and metal levels and no definite trend was observed for inter-metal relationships. Antimony, Cr, and Pb showed THQs greater than 1 at both dams which suggests health risks for consumers. Molybdenum has also shown a concerning THQs with some individuals exhibiting values ranging from 0.5 - 0.9. These findings suggest that consuming C. rendalli from the Inanda and Nagle dams could result in adverse health effects from Sb, Cr and Pb.

Holistic assessment of dimethoate toxicity in Carcinus aestuarii's muscle tissues.

Dimethoate (DMT) is one of the most harmful and commonly used organophosphate pesticides in agricultural lands to control different groups of parasitic insects. However, this pesticide is considered a dangerous pollutant for aquatic organisms following its infiltration in coastal ecosystems through leaching. Yet, our investigation aimed to gain new insights into the toxicity mechanism of DMT in the muscles of the green crab Carcinus aestuarii, regarding oxidative stress, neurotransmission impairment, histological aspects, and changes in lipid composition, assessed for the first time on the green crab's muscle. Specimens of C. aestuarii were exposed to 50, 100, and 200 µg DMT L-1 for 24 h. Compared to the negative control group, the higher the DMT concentration, the lower the saturated fatty acids (SFA), and the higher the monounsaturated fatty acids (MUFA). The significant increase in polyunsaturated fatty acid n-6 (PUFA n-6) was related to the high release, mainly, of linoleic acid (LA, C18: 2n6) and arachidonic acid (ARA, C20: 4n6) levels. Biochemical biomarkers showed that DMT exposure promoted oxidative stress, highlighted by increased levels of hydrogen peroxide (H2O2), malondialdehyde (MDA), advanced oxidation protein product levels (AOPP), and protein carbonyl (PCO). Furthermore, the antioxidant defense system was activated, as demonstrated by the significant changes in the enzymatic activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and reduced glutathione (GSH) levels associated with an adaptation process of C. aestuarii to cope with the DMT exposure. This pesticide significantly impairs the neurotransmission process, as evidenced by the inhibition of acetylcholinesterase (AChE) activity. Finally, several histopathological changes were revealed in DMT-treated crabs, including vacuolation, and muscle bundle loss.This research offered new insights into the toxic mechanism of DMT, pointing to the usefulness of fatty acid (FA) composition as a sensitive biomarker in littoral crabs.

High-performance electrically responsive artificial muscle materials for soft robot actuation.

Traditional robotic devices are often bulky and rigid, making it difficult for them to adapt to the soft and complex shapes of the human body. In stark contrast, soft robots, as a burgeoning class of robotic technology, showcase exceptional flexibility and adaptability, positioning them as compelling contenders for a diverse array of applications. High-performance electrically responsive artificial muscle materials (ERAMMs), as key driving components of soft robots, can achieve efficient motion and deformation, as well as more flexible and precise robot control, attracting widespread attention. This paper reviews the latest advancements in high-performance ERAMMs and their applications in the field of soft robot actuation, using ionic polymer-metal composites and dielectric elastomers as typical cases. Firstly, the definition, characteristics, and electro-driven working principles of high-performance ERAMMs are introduced. Then, the material design and synthesis, fabrication processes and optimization, as well as characterization and testing methods of the ERAMMs are summarized. Furthermore, various applications of two typical ERAMMs in the field of soft robot actuation are discussed in detail. Finally, the challenges and future directions in current research are analyzed and anticipated. This review paper aims to provide researchers with a reference for understanding the latest research progress in high-performance ERAMMs and to guide the development and application of soft robots. STATEMENT OF SIGNIFICANCE.