Nonclassical crystallization of goethite nanorods in limpet teeth by self-assembly of silica-rich nanoparticles reveals structure-mechanical property relations.

The intricate organization of goethite nanorods within a silica-rich matrix makes limpet teeth the strongest known natural material. However, the mineralization pathway of goethite in organisms under ambient conditions remains elusive. Here, by investigating the multi-level structure of limpet teeth at different growth stages, it is revealed that the growth of goethite crystals proceeds by the attachment of amorphous nanoparticles, a nonclassical crystallization pathway widely observed during the formation of calcium-based biominerals. Importantly, these nanoparticles contain a high amount of silica, which is gradually expelled during the growth of goethite. Moreover, in mature teeth of limpet, the content of silica correlates with the size of goethite crystals, where smaller goethite crystals are densely packed in the leading part with higher content of silica. Correspondingly, the leading part exhibits higher hardness and elastic modulus. Thus, this study not only reveals the nonclassical crystallization pathway of goethite nanorods in limpet teeth, but also highlights the critical roles of silica in controlling the hierarchical structure and the mechanical properties of limpet teeth, thus providing inspirations for fabricating biomimetic materials with excellent properties.

Strong and Tough MXene Bridging-induced Conductive Nacre.

Nacre is a classic model, providing an inspiration for fabricating high-performance bulk nanocomposites with the two-dimensional platelets. However, the "brick" of nacre, aragonite platelet, is an ideal building block for making high-performance bulk nanocomposites. Herein, we demonstrated a strong and tough conductive nacre through reassembling aragonite platelets with bridged by MXene nanosheets and hydrogen bonding, not only providing high mechanical properties but also excellent electrical conductivity. The flexural strength and fracture toughness of the obtained conductive nacre reach ~ 282 MPa and ~ 6.3 MPa m1/2, which is 1.6 and 1.6 times higher than that of natural nacre, respectively. These properties are attributed to densification and high orientation degree of the conductive nacre, which is effectively induced by the combined interactions of hydrogen bonding and MXene nanosheets bridging. The crack propagations in conductive nacre are effectively inhibited through crack deflection with hydrogen bonding, and MXene nanosheets bridging between aragonite platelets. In addition, our conductive nacre also provides a self-monitoring function for structural damage and offers exceptional electromagnetic interference shielding performance. Our strategy of reassembling the aragonite platelets exfoliated from waste nacre into high-performance artificial nacre, provides an avenue for fabricating high-performance bulk nanocomposites through the sustainable reutilization of shell resources.

Response of antioxidation and immunity to combined influences of pH and ammonia nitrogen in the spotted babylon (Babylonia areolata).

Spotted babylon were exposed to three different pH levels (7.0, 8.0 and 9.0) and four different concentrations of ammonia nitrogen (0.02, 1.02, 5.10 and 10.20 mg/L) in seawater to determine their acute toxicity and physiological responses to environmental fluctuation. The study evaluated four antioxidant enzymes: catalase (CAT), alkaline, superoxide dismutase (SOD), peroxidase (POD) and glutathione peroxidase (GSH-PX), and two immunoenzymes: acid phosphatase (ACP) and phosphatase (AKP). Over time, the immunoenzyme activity was significantly affected by pH and ammonia nitrogen concentration. After being exposed to pH and ammonia nitrogen, the spotted babylon showed signs of unresponsiveness to external stimuli, reduced vitality, slow movement, and an inability to maintain an upright position. Over time, the spotted babylon exhibited a trend of increasing and then decreasing GSH-PX, CAT, and SOD activities to adapt to the changing environment and enhance its immunity. On the contrary, the POD and ACP activities exhibited a decreasing trend initially, followed by an increasing trend over time and the AKP activity showed a gradual increase with time. The combined effect of pH and ammonia was found to be stronger than the effect of either factor alone. The interaction between pH and ammonia increased the activity of the spotted babylon antioxidant enzymes, induced oxidative stress, and reduced the ability of the spotted babylon's non-specific immune system to reverse it. Thus, the reverse-back of the spotted babylon was higher when pH and ammonia stress were dual than when pH or ammonia were single-factor stresses. The study results will establish a theoretical basis for analyzing the risk of multiple factors to the spotted babylon, and also enrich the basic information about the shellfish immune system.

Mechanisms of Digestive Enzyme Response to Acute Salinity Stress in Juvenile Yellowfin Tuna (Thunnus albacares).

This study investigates the effect of a sudden change in salinity for 48 h on the digestive enzyme activity of juvenile yellowfin tuna. The treatment included a control salinity of 32‱ in natural seawater and an experimental salinity of 29‱. Acute stress experiments were carried out on 72 juvenile yellowfin tuna (646.52 ± 66.32 g) for 48 h to determine changes in digestive enzyme activity in different intestinal sections over time (0 h, 12 h, 24 h, 48 h). The activities of pepsin, trypsin, α-amylase, lipase, and chymotrypsin in the digestive organs (stomach, foregut, and pyloric ceca) of juvenile yellowfin tuna were measured. Pepsin and pancreatic protease in the experimental group were significantly lower than in the control group (p < 0.05). α-amylase showed a fluctuating trend of decreasing and then increasing, and its activity trend was pyloric ceca > foregut > stomach. The lipase activity of gastric tissues decreased at the beginning and then increased, reaching a minimum at 24 h (2.74 ± 1.99 U·g protein-1). The change of lipase in the pyloric ceca and foregut was increasing and then decreasing. The lipase activity trend was pyloric ceca > foregut > stomach. The chymotrypsin showed a decreasing and increasing trend and then stabilized at 48 h with a pattern of pyloric ceca > foregut > stomach. Similarly, the gut villi morphology was not significantly altered in the acutely salinity-stressed compared to the non-salinity-stressed. This study suggests that salinity may change the digestive function of juvenile yellowfin tuna, thereby affecting fish feeding, growth, and development. On the contrary, yellowfin tuna is highly adapted to 29‱ salinity. However, excessive stress may negatively affect digestive enzyme activity and reduce fish digestibility. This study may provide a scientific basis for a coastal aquaculture water environment for yellowfin tuna farming, which may guide the development and cultivation of aquaculture.

Fermented Astragalus membranaceus could promote the liver and intestinal health of juvenile tiger grouper (Epinephelus fuscoguttatus).

In order to understand the effects of fermented Astragalus membranaceus (FAM) on the liver and intestinal health of tiger grouper (Epinephelus fuscoguttatus), this study was conducted. This study evaluates the effects of different levels of FAM on liver and intestinal tissue structure, serum biochemical parameters, intestinal digestive enzyme, and microbiota structure of tiger grouper. Fish were fed with diets (crude protein ≥ 48.0%, crude fat ≥ 10.0%) with five levels of FAM (L1:0.25%, L2: 0.5%, L3: 1%, L4: 2% and L5: 4%) in the experimental groups and a regular diet was used as the control (L0: 0%) for 8 weeks. Compared with AM, the protein content of FAM was significantly changed by 34.70%, indicating that a large amount of bacterial protein was produced after AM fermentation, and its nutritional value was improved. FAM had significant effects on the growth performance of tiger grouper (p < 0.05). The high-density lipoprotein cholesterol (HDL-C) was highest in L4 group, being significantly different from L0 group. The area and diameter of hepatocytes were lowest in L3 and L4, and the density of hepatocyte was highest in L4 group and relatively decreased in L5 group. The mucosal height and muscular thickness were highest in L3 group. The intestinal microbiota structure of tiger grouper was changed under the intervention of FAM. The lower abundance of potential pathogenic bacteria and higher abundance of probiotics colonization in the L4 group showed that the dose of FAM had the best effect on improving the health of intestinal microbiota. This study indicates that the addition of FAM in the feed contributes to liver health, improves intestinal morphology, and regulates the intestinal microbiota of tiger grouper. The addition ratio of 1%-2% is better for intestinal and liver health, and a high addition ratio will cause liver damage. Our work will provide a reference for the addition and management of FAM in the aquaculture industry.

Acute thermal stress increased enzyme activity and muscle energy distribution of yellowfin tuna.

Heat is a powerful stressor for fish living in natural and artificial environments. Understanding the effects of heat stress on the physiological processes of fish is essential for better aquaculture and fisheries management. In this experiment, a heating rod was used to increase the temperature at 2°C/h to study the changes of energy allocation (CEA) and energy metabolity-related enzyme activities, including pepsin, trypsin, amylase, lipase, acid phosphatase, lactate dehydrogenase, alanine aminotransferase, glutamic oxalic aminotransferase and energy reserve (Ea), energy expenditure (ETS), in juvenile yellowfin tuna cells under acute temperature stress. The results showed that the Ea of juvenile yellowfin tuna muscles in response to high temperature (34°C) was significantly lower than that of the control (28°C), and it also increased ETS. At 6 h, CEA decreased slightly in the high-temperature group, but, the difference in CEA between 24 h and 0 h decreased. After heat stress for 6 h, the activities of acid phosphatase (ACP), lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and glutamic oxalacetic transaminase (AST) increased, indicating that the metabolic rate was accelerated. After heat stress for 24 h, the activity of ALT decreased, indicating that with time elapsed, the activities of some protein metabolizing enzymes increased, and some decreased. In this study, digestive enzymes, trypsin and lipase increased gradually. After heat stress, Ea and Ec change significantly. Yellowfin tuna muscles use lipids in response to sharp temperature increases at high temperatures, red muscles respond to temperature changes by increasing energy in the early stages, but not nearly as much, and white muscles reduce lipids.

Daily Rhythmicity of Muscle-Related and Rhythm Genes Expression in Mackerel Tuna (Euthynnus affinis).

The aim of this study was to investigate the circadian rhythm of muscle-related gene expression in mackerel tuna under different weather conditions. The experiment was carried out under two weather conditions at four sampling times (6:00, 12:00, 18:00, and 24:00) to determine the expression of growth, function, and rhythm genes: white muscle rhythm genes were rhythmic on sunny and cloudy days, except for PER3 and RORA; all functional genes had daily rhythmicity. Red muscle had daily rhythmicity on both sunny and cloudy days; functional genes had daily rhythmicity except for MBNL. The expression levels of the rhythm gene PER1 were determined to be significantly different by independent t-test samples in white muscle at 6:00, 12:00, 18:00, and 24:00 under different weather conditions; the expression levels of the functional genes MBNL and MSTN were both significantly different. In the red muscle, the expression of the rhythm genes PER3, REVERBA, and BMAL1 was determined by independent t-test samples at 6:00, 12:00, 18:00, and 24:00 on cloudy and sunny days; the functional gene MBNL was significantly different. The present study showed that mackerel tuna muscle rhythm genes and functional genes varied significantly in expression levels depending on weather, time of day, and light intensity and that the expression levels of myogenic genes were closely related to clock gene expression. The fish were also able to adapt to changes in light intensity in different weather conditions through positive physiological regulation.

Changes in pH and Nitrite Nitrogen Induces an Imbalance in the Oxidative Defenses of the Spotted Babylon (Babylonia areolata).

In order to reveal the acute toxicity and physiological changes of the spotted babylon (Babylonia areolata) in response to environmental manipulation, the spotted babylon was exposed to three pH levels (7.0, 8.0 and 9.0) of seawater and four concentrations of nitrite nitrogen (0.02, 2.7, 13.5 and 27 mg/L). The activities of six immunoenzymes, superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT), acid phosphatase (ACP), alkaline phosphatase (AKP) and peroxidase (POD), were measured. The levels of pH and nitrite nitrogen concentrations significantly impacted immunoenzyme activity over time. After the acute stress of pH and nitrite nitrogen, the spotted babylon appeared to be unresponsive to external stimuli, exhibited decreased vigor, slowly climbed the wall, sank to the tank and could not stand upright. As time elapsed, with the extension of time, the spotted babylon showed a trend of increasing and then decreasing ACP, AKP, CAT and SOD activities in order to adapt to the mutated environment and improve its immunity. In contrast, POD and GSH-PX activities showed a decrease followed by an increase with time. This study explored the tolerance range of the spotted babylon to pH, nitrite nitrogen, and time, proving that external stimuli activate the body's immune response. The body's immune function has a specific range of adaptation to the environment over time. Once the body's immune system was insufficient to adapt to this range, the immune system collapsed and the snail gradually died off. This study has discovered the suitable pH and nitrite nitrogen ranges for the culture of the spotted babylon, and provides useful information on the response of the snail's immune system.

Contribution of boundary non-stoichiometry to the lower-temperature plasticity in high-pressure sintered boron carbide.

The improvement of non-oxide ceramic plasticity while maintaining the high-temperature strength is a great challenge through the classical strategy, which generally includes decreasing grain size to several nanometers or adding ductile binder phase. Here, we report that the plasticity of fully dense boron carbide (B4C) is greatly enhanced due to the boundary non-stoichiometry induced by high-pressure sintering technology. The effect decreases the plastic deformation temperature of B4C by 200 °C compared to that of conventionally-sintered specimens. Promoted grain boundary diffusion is found to enhance grain boundary sliding, which dominate the lower-temperature plasticity. In addition, the as-produced specimen maintains extraordinary strength before the occurrence of plasticity. The study provides an efficient strategy by boundary chemical change to facilitate the plasticity of ceramic materials.

3D relationship between hierarchical canal network and gradient mineralization of shark tooth osteodentin.

Osteodentin is a dominant mineralized collagenous tissue in the teeth of many fishes, with structural and histological characteristics resembling those of bone. Osteodentin, like bone, comprises osteons as basic structural building blocks, however, it lacks the osteocytes and the lacuno-canalicular network (LCN), which are known to play critical roles in controlling the mineralization of the collagenous matrix in bone. Although numerous vascular canals exist in osteodentin, their role in tooth maturation and the matrix mineralization process remain poorly understood. Here, high resolution micro-computed tomography (micro-CT) and focused ion beam-scanning electron microscopy (FIB-SEM) were used to obtain 3D structural information of osteodentin in shark teeth at multiple scales. We observed a complex 3D network of primary canals with a diameter ranging from ∼10 µm to ∼120 µm, where the canals are surrounded by osteon-like concentric layers of lamellae, with 'interosteonal' tissue intervening between neighboring osteons. In addition, numerous hierarchically branched secondary canals extended radially from the primary canals into the interosteonal tissue, decreasing in diameter from ∼10 µm to hundreds of nanometers. Interestingly, the mineralization degree increases from the periphery of primary canals into the interosteonal tissue, suggesting that mineralization begins in the interosteonal tissue. Correspondingly, the hardness and elastic modulus of the interosteonal tissue are higher than those of the osteonal tissue. These results demonstrate that the 3D hierarchical canal network is positioned to play a critical role in controlling the gradient mineralization of osteodentin, also providing valuable insight into the formation of mineralized collagenous tissue without osteocytes and LCN. STATEMENT OF SIGNIFICANCE: Bone is a composite material with versatile mechanical properties. Osteocytes and their lacuno-canalicular network (LCN) are known to play critical roles during formation of human bone. However, the bone and osteodentin of many fishes, although lacking osteocytes and LCN, exhibit similar osteon-like structure and mechanical functions. Here, using various high resolution 3D characterization techniques, we reveal that the 3D network of primary canals and numerous hierarchically branched secondary canals correlate with the mineralization gradient and micromechanical properties of osteonal and interosteonal tissues of shark tooth osteodentin. This work significantly improves our understanding of the construction of bone-like mineralized tissue without osteocytes and LCN, and provides inspirations for the fabrication of functional materials with hierarchical structure.

Bioinspired Additive Manufacturing of Hierarchical Materials: From Biostructures to Functions.

Throughout billions of years, biological systems have evolved sophisticated, multiscale hierarchical structures to adapt to changing environments. Biomaterials are synthesized under mild conditions through a bottom-up self-assembly process, utilizing substances from the surrounding environment, and meanwhile are regulated by genes and proteins. Additive manufacturing, which mimics this natural process, provides a promising approach to developing new materials with advantageous properties similar to natural biological materials. This review presents an overview of natural biomaterials, emphasizing their chemical and structural compositions at various scales, from the nanoscale to the macroscale, and the key mechanisms underlying their properties. Additionally, this review describes the designs, preparations, and applications of bioinspired multifunctional materials produced through additive manufacturing at different scales, including nano, micro, micro-macro, and macro levels. The review highlights the potential of bioinspired additive manufacturing to develop new functional materials and insights into future directions and prospects in this field. By summarizing the characteristics of natural biomaterials and their synthetic counterparts, this review inspires the development of new materials that can be utilized in various applications.

Cloning, Expression Analysis and SNP Screening of the kiss1 Gene in Male Schizothorax biddulphi.

Schizothorax biddulphi is an endemic fish distributed only in southern Xinjiang, China. Due to overfishing, water conservancy facilities, and other factors, as well as inherent biological limitations, resource recovery is quite difficult. For endangered fish with slow growth, late sexual maturity, and insufficient natural population supplementation, large-scale artificial reproduction and breeding are important for restoring resources. Therefore, it is urgent to optimize the reproductive regulation methods of the fish. The kiss1 gene is a key regulator of the reproductive regulation cascade, and identifying and analyzing the role of kiss1 are important for further elucidating the reproductive mechanism of S. biddulphi. To understand the characteristics of the kiss1 of S. biddulphi, the full-length cDNA sequence of kiss1 was obtained in this study, and its tissue expression specificity and association with phenotypic traits were analyzed in male fish. The full-length cDNA sequence of kiss1 in S. biddulphi was 658 bp, with an ORF of 327 bp, and encoded a 108-amino acid, unstable protein. Homology results indicated that kiss1 was highly conserved. qPCR showed kiss1 expression in different tissues in male S. biddulphi, with the highest expression in the gonads, followed by muscle, and significantly lower expression in the swim bladder, pituitary gland, heart, hypothalamus, gill, fin, liver, eye, and mid-kidney. qPCR revealed three SNP loci in the exonic region of kiss1. The c.3G>T locus was significantly correlated (p < 0.05) with gonad mass and the maturation coefficient in S. biddulphi. These results will help uncover the reproductive endocrinology network of S. biddulphi, improve artificial breeding technology for fish, and unveil new directions for breeding excellent strains of S. biddulphi and molecular marker-assisted breeding.

Bioprocess inspired formation of calcite mesocrystals by cation-mediated particle attachment mechanism.

Calcite mesocrystals were proposed, and have been widely reported, to form in the presence of polymer additives via oriented assembly of nanoparticles. However, the formation mechanism and the role of polymer additives remain elusive. Here, inspired by the biomineralization process of sea urchin spine comprising magnesium calcite mesocrystals, we show that calcite mesocrystals could also be obtained via attachment of amorphous calcium carbonate (ACC) nanoparticles in the presence of inorganic zinc ions. Moreover, we demonstrate that zinc ions can induce the formation of temporarily stabilized amorphous nanoparticles of less than 20 nm at a significantly lower calcium carbonate concentration as compared to pure solution, which is energetically beneficial for the attachment and occlusion during calcite growth. The cation-mediated particle attachment crystallization significantly improves our understanding of mesocrystal formation mechanisms in biomineralization and offers new opportunities to bioprocess inspired inorganic ions regulated materials fabrication.

Bioinspired Strategy for Efficient TiO2/Au/CdS Photocatalysts Based On Mesocrystal Superstructures in Biominerals and Charge-Transfer Pathway in Natural Photosynthesis.

Natural photosynthesis involves an efficient charge-transfer pathway through exquisitely arranged photosystems and electron transport intermediates, which separate photogenerated carriers to realize high quantum efficiency. It inspires a rational design construction of artificial photosynthesis systems and the architectures of semiconductors are essential to achieve optimal performance. Of note, biomineralization processes could form various mesocrystals with well-ordered superstructures for unique optical applications. Inspired by both natural photosynthesis and biomineralization, we construct a ternary superstructure-based mesocrystal TiO2 (meso-TiO2)/Au/CdS artificial photosynthesis system by a green photo-assisted method. The well-ordered superstructure of meso-TiO2 and efficient charge-transfer pathway among the three components are crucial for retarding charge recombination. As a result, the meso-TiO2/Au/CdS photocatalyst displays enhanced visible light-driven photocatalytic hydrogen evolution (4.60 mmol h-1 g-1), which is 3.2 times higher than that of commercial TiO2 (P25)/Au/CdS with disordered TiO2 nanocrystal aggregates (1.41 mmol h-1 g-1). This work provides a promising bioinspired design strategy for photocatalysts with an improved solar conversion efficiency.

Crystal Structure and Bond-Valence Investigation of Nitrogen-Stabilized LiAl5O8 Spinels.

An in-depth insight into the effect of nitrogen substitution on structural stabilization is important for the design of new spinel-type oxynitride materials with tailored properties. In this work, the crystal structures of ordered and disordered LiAl5O8 obtained by slow cooling and rapid quenching, respectively, were analyzed by a X-ray diffraction (XRD) Rietveld refinement and OccQP program. The variation in the bonding state of atoms in the two compounds was explored by the bond valence model, which revealed that the instability of spinel-type LiAl5O8 crystal structure at room temperature is mainly due to the severe under-bonding of the tetrahedrally coordinated Al cations. With the partial substitution of oxygen with nitrogen in LiAl5O8, a series of the nitrogen-stabilized spinel LiyAl(16+x-y)/3O8-xNx (0 < x < 0.5, 0 < y < 1) was successfully prepared. The crystal structures were systematically investigated by the powder XRD structural refinement combined with 7Li and 27Al magic-angle spinning nuclear magnetic resonance. All the Li+ ions entered the octahedra, while the Al resonances may be composed of multiple non-equivalent Al sites. The structural stability of spinel LiyAl(16+x-y)/3O8-xNx at ambient temperature was attributed to the cationic vacancies and high valence generated by the N ions, which alleviated the under-bonding state of the tetrahedral Al-O bond. This work provides a new perspective for understanding the composition-structure relationship in spinel compounds with multiple disorders.

The combined effects of temperature and salinity on the digestion and respiration metabolism of Pinctada fucata.

The combined effects of temperature and salinity on the digestion and respiration metabolism of Pinctada fucata were evaluated via response surface methodology and box-benhnken design under laboratory condition. Results indicated that the primary and secondary effects of salinity and temperature had significant effects on amylase (AMS) of P. fucata (P < 0.05)., The digestive enzyme reached the maximum activity when temperature was 26 °C. The AMS and trypsin (TRYP) increased at first, and then decreased with increasing temperature. The Lipase (LPS) was positively correlated with either salinity or temperature. Salinity had no significant effect on TRYP as a primary effect (P > 0.05), but had a significant effect on TRYP as a secondary effect (P < 0.01). These effects were completely opposite to the effect of temperature on pepsin (PEP) as primary and secondary effects. The combined effects of salinity and temperature on AMS, TRYP and PEP were significant (P < 0.01), but had no significant effect on LPS (P > 0.05). The primary, secondary and interaction effects of salinity had significant effects on NKA (Na+-K+-ATPase) of P. fucata (P < 0.05), and NKA presented a U-shaped distribution with increasing salinity. The quadratic and interactive effects of temperature had a significant effect on AKP (P < 0.05), and AKP showed a U-shaped distribution with increasing temperature. Lactate dehydrogenase (LDH) activity decreased at first, and then increased when temperature and salinity changed from 20 to 30 °C and 23-33 ‰, respectively. The expression of GPX gene affected by temperature in gills may be delayed compared with that in hepatopancreas, and its expression is tissue-specific. The appropriate digestion and respiratory metabolism index models were established under the combined temperature and salinity conditions. The optimization results showed that the optimal combination of temperature and salinity was 26.288 °C/28.272‰. The desirability was 0.832. Results from the present study will provide a theoretical reference for shellfish culture affected by environmental interactions and the establishment of related index models.

Dietary curcumin supplementation enhances intestinal immunity and gill protection in juvenile greater amberjack (Seriola dumerili).

A 8-week feeding trial was conducted to determine the effects of dietary supplementation with curcumin on growth, intestinal health, and gills resistance to ammonia stress in juvenile Seriola dumerili. Three isonitrogenous and isolipidic test diets were prepared by supplementing incremental levels of dietary curcumin at 0% (CUR0%, control), 0.01% (CUR0.01%), 0.02% (CUR0.02%), respectively. Fish were fed with experimental diet. Recovery and protection capacity after ammonia challenge assay was adopted to test the effect of curcumin. At the end of the feeding trial, the results showed that dietary supplementation with proper curcumin level had a significant positive effect on fish survival and intestinal histology structure. Meanwhile, dietary supplementation with proper curcumin level can improve intestinal health by increasing immune enzyme activity, up-regulating the expression of anti-inflammatory cytokines, down-regulating the expression of pro-inflammatory cytokines and regulating other immune-related genes. Subsequently, after the ammonia challenge and recovery experiment, the results of antioxidant-related genes and antioxidant enzymes showed that dietary supplementation with proper curcumin level can improve the gill protective and recovery capacity from ammonia stress through increasing antioxidant capacity. These results suggest that dietary supplementation with proper curcumin can promote the growth, intestinal health, gill resistance and recovery to ammonia stress of S. dumerili.

Effects of Eugenol on Water Quality and the Metabolism and Antioxidant Capacity of Juvenile Greater Amberjack (Seriola dumerili) under Simulated Transport Conditions.

This study investigated the effects of added eugenol on water quality and the metabolism and antioxidant capacity of the liver and gills of the greater amberjack (Seriola dumerili) during simulated transport. The juvenile fish (10.34 ± 1.33 g) were transported in sealed plastic bags containing different eugenol concentrations at a density of 24.79 kg/m3 for 8 h. The different eugenol concentrations were divided into five groups: 0 µL/mL (control group), 0.0125 µL/mL, 0.025 µL/mL, 0.0375 µL/mL, and 0.05 µL/mL, with three replicates of each. The results showed that 0.05 µL/mL of eugenol could significantly increase dissolved oxygen, but 0.025 µL/mL-0.0375 µL/mL resulted in a significant decrease in dissolved oxygen and significant increases in NH4+-N and NO2--N. It was found that 0.05 µL/mL of eugenol caused significant up-regulation of the relative expression of CPT-1 in the liver, significant down-regulation of the relative expression of FAS and PK in the liver and gills, a significant increase in glycogen concentration, and a significant decrease in glucose concentration. This suggests that 0.05 µL/mL of eugenol could reduce the metabolic capacity of fish. In addition, 0.05 µL/mL of eugenol caused significant up-regulation of the relative expression of CAT and a significant decrease of MDA concentration in the liver. Meanwhile, the gills showed significant up-regulation of CAT relative expression, significant down-regulation of Keap1 relative expression, and a significant increase in GSH activity, resulting in a significant increase in MDA concentration when the concentration of eugenol reached or exceeded 0.025 µL/mL. This suggests that 0.05 µL/mL eugenol could improve the antioxidant capacity of fish and lipid peroxidation levels in the gills. In conclusion, the addition of 0.05 µL/mL eugenol could improve water quality, and the metabolic and antioxidant capacities of liver and gills, but it could also increase lipid peroxidation levels in the gills under transport conditions.

Combined Effects of Temperature and Salinity Affect the Surviv-Al of Asian Green Mussel (Perna viridis) through Digestive and Antioxidant Performance.

Changes in temperature and salinity of the marine environment fluctuate continuously, and the effects of these changes on shellfish survival are significant. In this study, the survival rate of adult Asian green mussels (Perna viridis) was measured after short-term treatments (7 days) for a range of temperature (20 °C, 25 °C, 30 °C) and salinity (23‱, 28‱, 33‱). The digestive (amylase, lipase, trypsin and pepsin activities) and antioxidant performance (SOD and GPX gene expression; SOD, GPX and CAT activities; GSH and MDA Concentration) were measured and MANOVA results were obtained using a generalized linear model between certain factors (temperature (T), salinity (S) and temperature × salinity (T × S)) and survival rate. Both T and T × S significantly affected the survival rate of Asian green mussels. The overall relationship between the survival rate of P. viridis and T and S within the experimental range can be summarised by the equation: ln(Survival rate) = 54.9282 - 2.5627 × T - 3.6180 × S + 0.1857 × T × S + 0.0156 × T2 + 0.0520 × S2 - 0.0012 × T2 × S - 0.0023 × T × S2. The optimal temperature-salinity combination was 23.698 °C/30.760‱. T, S and T × S all had a significant impact on amylase and lipase activities of Asian green mussels. In the hepatopancreas, gill, mantle, adductor muscle, gonad and foot tissues of Asian green mussel, the SOD and GPX gene expression were responsive to temperature-salinity changes. The antioxidant performance of the combinations far from the optimal temperature-salinity combination were significantly improved. Our results suggest that combined temperature and salinity effects have a regular impact on the survival of Asian green mussels and that there is a link between survival and digestive and antioxidant performance.

Ultrafine-Grained Tungsten Heavy Alloy Prepared by High-Pressure Spark Plasma Sintering.

Tungsten heavy alloy (WHA) is an ideal material employed for kinetic energy penetrators due to its high density and excellent mechanical properties. However, it is difficult to obtain ultrafine-grained tungsten alloy with excellent properties by traditional powder metallurgy method because of severe grain growth at a high sintering temperature with a long soaking time. In this study, the sintering behavior of tungsten alloys was studied at 800 to 1300 °C, and highly dense 93W-5.6Ni-1.4Fe (wt.%) WHA was successfully fabricated at a low temperature of 950 °C with a high pressure of 150 MPa by spark plasma sintering. The as-sintered tungsten alloy possesses a high relative density (98.6%), ultrafine grain size (271 nm) and high dislocation density (2.6 × 1016 m-2), which results in excellent properties such as a high hardness (1079 HV1). The high sintering pressure is considered to support an additional driving force for the sintering and lead to a low-temperature densification, which effectively limits grain growth.