Splenic tissue injury and physiological response mechanisms in juvenile yellowfin tuna (Thunnus albacares) under acute cold stress.

Abnormal seawater temperatures driven by global climate change are profoundly disrupting the physiological homeostasis and immune regulation of marine fish. As a warm-blooded pelagic species, yellowfin tuna (Thunnus albacares) possesses partial thermoregulatory capability but still experiences significant physiological stress under abrupt cold exposure. The spleen, a key immune and metabolic organ, is highly sensitive to temperature fluctuations and serves as a critical indicator of cold stress effects.

Cold stress disrupts gill homeostasis in juvenile yellowfin tuna (Thunnus albacares) by altering oxidative, metabolic, and immune responses.

Acute cold stress can disrupt physiological homeostasis in marine fish and may induce pronounced metabolic and immune responses in pelagic species such as yellowfin tuna (Thunnus albacares), which possess regional endothermic capabilities. As a key tissue interfacing with the environment, the gill plays essential roles in gas exchange, ion regulation, immune defense, and energy metabolism, making it highly susceptible to thermal fluctuations. This study investigated the physiological responses of gill tissue in juvenile yellowfin tuna under acute cold stress, using two treatment groups-LT (24 °C) and ULT (18 °C)-with a control group (CG, 30 °C).

Bio-Inspired Synthesis of Injectable, Self-Healing PAA-Zn-Silk Fibroin-MXene Hydrogel for Multifunctional Wearable Capacitive Strain Sensor.

Conductive hydrogels have important application prospects in the field of wearable sensing, which can identify various biological signals for human motion monitoring. However, the preparation of flexible conductive hydrogels with high sensitivity and stability to achieve reliable signal recording remains a challenge. Herein, we prepared a conductive hydrogel by introducing conductive TiCT MXene nanosheets into a dual network structure formed by Zn crosslinked polyacrylic acid and silk fibroin for use as a wearable capacitive strain sensor.

Protein Immobilization Inspired Lysosomal Disruption for Efficient Nuclear Drug Delivery.

The high metabolism and excessive growth of tumor cells result in the development of a tumor microenvironment (TME) and enhanced lysosomal activity within the cells, which can eliminate chemotherapeutics. Consequently, the design of nanocarriers that respond to TME and target tumor cell lysosomes represents an optimal strategy to enhance drug specificity and utilization efficiency. Herein, inspired by protein immobilization, a dual-responsive supramolecular nanomedicine FPA/DOX is developed for specifically targeting the TME and tumor cell lysosomes.

Effect of intestinal microbiota on growth rate of Babylonia areolata.

To analyze the differences in the intestinal microbiota structure of different growth rates of Babylonia areolata, the sequencing of the V3-V4 regions of 16S rDNA from intestinal samples was performed. Evaluation of the richness of microbiota of the samples by calculating Shannon index, Simpson index and Chao1 index showed that the community diversity and richness of the intestinal microbiota of B. areolata changed for different growth rates.

Mechanism of digestion enzymes and related genes in response to acute ammonia-nitrogen stress in juvenile yellowfin tuna (Thunnus albacares).

To investigate the impact of acute ammonia stress (NH-N) on the digestive physiology and gene expression in juvenile yellowfin tuna (Thunnus albacares), we used natural seawater (0 mg/L ammonia) as the control. Ammonia concentrations of 5 and 10 mg/L were set to measure the levels of digestive enzymes in the intestine, liver, stomach, and pyloric cecum at intervals of 6, 24, and 36 h. Additionally, this experiment measured antioxidant and immunity genes in the foregut.

Reusable Liquid Metal-Based Hierarchical Hydrogels with Multifunctional Sensing Capability for Electrophysiology Electrode Substitution.

Electrophysiological electrode patches are often used to collect surface electrophysiological signals to monitor and evaluate human health. However, commercial Ag/AgCl gels are very susceptible to electrode-skin interface interference during rehabilitation exercises and cannot achieve a stable collection of electrophysiological signals. In order to solve this challenge, this paper designed a liquid metal-based hierarchical hydrogel, which has a series of great performances, including adhesion to various substrates, efficient self-healing ability, excellent stretchability, and conductivity.

Regulating Growth of Strontium Carbonate in Self-Assembled Chiral Chitin Matrices with Robust Mechanical Properties.

The exoskeleton of arthropods exhibits a Bouligand structure, composed of a chitin matrix and calcium carbonate crystals, which confer exceptional mechanical properties. While many studies focus on the relationship between structure and performance, few investigate the mineral growth process within the Bouligand matrix. Here, chiral chitin films are prepared through evaporation-induced self-assembly of chitin nanowhiskers, and subsequently incubated in SrCO mineralizing solution.

Tuning the Intrafibrillar Collagen Mineralization Rate and Mechanical Properties Through Polyelectrolyte-Controlled Formation and Crystallization of Amorphous Precursor.

Non-collagenous proteins (NCPs) play a crucial role in directing intrafibrillar collagen mineralization during hard tissue formation, however, their functions and control mechanisms remain elusive and controversial. Here, employing poly(allylamine hydrochloride) (PAH) as the NCPs analog, the potential correlation between the precursor crystallization process and the intrafibrillar collagen mineralization process controlled by NCPs/NCPs analogs, as well as its effects on kinetics and mechanical properties are systematically investigated. Results demonstrate that liquid-liquid phase separation of PAH and phosphate ions promotes the formation of amorphous calcium phosphate (ACP) liquid precursor and controls their composition, size, and physicochemical properties.

Nanocluster-Induced Liquid-like Precursor Formation and Crystallization: In Situ Visualization and 3D Reconstruction.

Revealing the crystallization mechanism of inorganic materials modulated by organic molecules has broad implications in biomineralization, crystallography, and materials science. However, directly visualizing the participation of organic molecules in the inorganic materials' crystallization process remains a significant challenge. Here, we introduce carboxyl-functionalized gold nanoclusters (Au NCs) as an alternative to polymers for investigating CaCO crystallization via the transient "Au NCs-induced liquid precursor" phase, similar to "polymer-induced liquid precursor".

Effects of Polyacrylic Acid with Different Molecular Weights on Stress Generation through Regulating the Growth of Calcium Carbonate within Collagen.

Mineralized collagen fibrils are the building blocks of bone, and the mineralization of collagen fibrils is generally regulated by noncollagenous proteins (NCPs). However, the functions of NCPs are difficult to investigate in vivo. Here, we use poly(acrylic acid) (PAA) with different molecular weights (5, 50, 450, and 4000 kDa) as analogs of NCPs and explore their effects on collagen mineralization in vitro.

Bridging Biological Multiscale Structure and Biomimetic Ceramic Construction.

The brittleness of traditional ceramics severely limits their application progress in engineering. The multiscale structural design of organisms can solve this problem, but it still lacks sufficient research and attention. The underlined main feature is the multiscale hierarchical structures composed of basic nano-microstructure units arranged in order, which is currently impossible to achieve through artificial synthesis driven by high temperatures.

Enhanced Ion Transport Through Organized Cadmium Carbonate Nanocrystals in Collagen Fibrils for Efficient Biological Memristors.

Owing to the unique assembly of collagen molecules, collagen fibrils have a confined structure that can effectively guide the intrafibrillar-oriented growth of inorganic crystals, such as hydroxyapatite and calcium carbonate. However, utilizing this organized structure of mineralized collagen fibrils for rapid ion transport remains challenging. Herein, the oriented growth of functional cadmium carbonate (CdCO) nanocrystals is reported within collagen fibrils and demonstrates that different areas within a single mineralized collagen fibril exhibit a uniform orientation.

Achieving Superhardness and Enhanced Toughness in High-Entropy Boride-Based Composites by Tailoring Their Multi-Scale Microstructures.

Unlike strong yet tough high entropy alloys, high entropy ceramics normally exhibit good hardness but poor strength and fracture toughness. To overcome this obstacle, BC-(ZrHfNbTaTi)B composites with a unique hierarchical microstructure are designed and prepared by boronizing reaction sintering of dual-phase multicomponent carbides. In the as-obtained composites, massive platelet-like aggregations assembled by core-rim structured (ZrHfNbTaTi)B fine grains are distributed randomly in the BC matrix.

3D-printable liquid metal-based hydrogel for use as a multifunctional epidermal sensor.

Conductive hydrogels have wide application prospects in flexible electronics, biosensors, and soft robotics because of their high flexibility, adjustable mechanical properties, and excellent electrochemical properties. However, it is difficult for a pure conductive polymer or rigid conductive filler hydrogel to meet the application requirements regarding electricity, mechanics, biocompatibility, and stability. To solve this problem, a special combination of polyacrylic acid (PAA) and liquid metal (LM) was adopted.

Underwater Superoleophobic and Transparent Films with Mechanical Robustness and High Durability in Harsh Environments.

Underwater superoleophobic and transparent (UST) films are promising in applications, such as advanced optical devices in marine environments. However, the mechanical robustness and durability in harsh environments of the existing UST films are still unsatisfactory. In this work, we present a free-standing nacre-inspired mineralized UST (NIM-UST) film with high aragonite content and excellent mechanical properties toward robust underwater superoleophobicity on two surfaces and transparency (94%) in harsh seawater environments.

The Impact of Acute Ammonia Nitrogen Stress on the Gill Tissue Structure and Antioxidant Ability of Gills and Red and White Muscle in Juvenile Yellowfin Tuna ().

To explore the impacts of acute ammonia nitrogen (NH-N) stress on gill structure and the antioxidant ability of red and white muscles in juvenile yellowfin tuna (), this study used natural seawater as a control, establishing two experimental NH-N groups at 5 and 10 mg/L. Gills and red and white muscle were taken at 6, 24, and 36 h for the determination of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GHS-PX) levels, and to observe gill structure. The results indicated that, with increasing time, the MDA concentration and CAT activity in the gills of the 5 mg/L group showed a trend of first increasing and then decreasing, while SOD activity exhibited a downward trend.

Stabilization and crystallization mechanism of amorphous calcium carbonate.

Amorphous phases hold great promise in diverse applications and are widely used by organisms as precursors to produce biominerals with complex morphologies and excellent properties. However, the stabilization and crystallization mechanisms of amorphous phases are not fully understood, especially in the presence of additives. Here, using amorphous calcium carbonate (ACC) as the model system, we systematically investigate the crystallization pathways of amorphous phases in the presence of poly(Aspartic acid) (pAsp) with various chain lengths.

Intrafibrillar calcium carbonate mineralization of electrospinning polyvinyl alcohol/collagen films with improved mechanical and bioactive properties.

Collagen films play an essential role in guided bone-regeneration (GBR) techniques, which create space, promote cell adhesion, and induce osteogenic differentiation. It is therefore crucial to design appropriate GBR films to facilitate bone regeneration. However, current electrospun collagen scaffolds used as bioactive materials have limited clinical applications due to their poor mechanical properties.

The Impact of Acute Ammonia Nitrogen Stress on Serum Biochemical Indicators and Spleen Gene Expression in Juvenile Yellowfin Tuna ().

The presence of ammonia nitrogen in water has a significant impact on the serum and spleen of fish, potentially leading to changes in substances such as proteins in the serum while also causing damage to the immune function of the spleen. To investigate the effects of ammonia nitrogen (NH-N) stress on juvenile yellowfin tuna (), this study established three NH-N concentrations, 0, 5, and 10 mg/L, denoted as L0, L1, and L2, respectively. Serum and spleen samples were collected at 6, 24, and 36 h.

Nanoporous Aramid Nanofiber Separators with High Modulus and Thermal Stability for Safe Lithium-Ion Batteries.

Developing high-safety separators is a promising strategy to prevent thermal runaway in lithium-ion batteries (LIBs), which stems from the low melting temperatures and inadequate modulus of commercial polyolefin separators. However, achieving high modulus and thermal stability, along with uniform nanopores in these separators, poses significant challenges. Herein, the study presents ultrathin nanoporous aramid nanofiber (ANF) separators with high modulus and excellent thermal stability, enhancing the safety of LIBs.

Effects of Ammonia Concentration on Sperm Vitality, Motility Rates, and Morphology in Three Marine Bivalve Species: A Comparative Study of the Noble Scallop , Chinese Pearl Oyster , and Small Rock Oyster .

Ammonium (NH) plays a crucial role in the reproductive processes of key biotic groups in aquatic ecosystems-bivalves. This study aims to elucidate the effects of three different ammonium ion concentrations on sperm vitality, swimming kinematics, and morphology of , , and . The results indicate that the sperm vitality and motility rates of and are inversely proportional to the ammonium concentration, especially in the treatment group with an ammonium concentration of 3 mmol/L, where the decrease in sperm vitality and motility is most significant.

Toxic Effects of Carbaryl Exposure on Juvenile Asian Seabass ().

This study examines the physiological and immunological effects of 0.5 ppm carbaryl exposure on juvenile Asian seabass () over 12 h to 72 h. Notable results include decreased activities of liver enzymes catalase (CAT), lactate dehydrogenase (LDH), and glutathione peroxidase (GSH-PX), while superoxide dismutase (SOD) levels remained stable, with the lowest activities of CAT and GSH-PX observed at 72 h.