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The body patterning of trochophore larvae is important for understanding spiralian evolution and the origin of the bilateral body plan. However, considerable variations are observed among spiralian lineages, which have adopted varied strategies to develop trochophore larvae or even omit a trochophore stage. Some spiralians, such as patellogastropod mollusks, are suggested to exhibit ancestral traits by producing equal‐cleaving fertilized eggs and possessing "typical" trochophore larvae. In recent years, we developed a potential model system using the patellogastropod Lottia peitaihoensis (= Lottia goshimai). Here, we introduce how the species were selected and establish sources and techniques, including gene knockdown, ectopic gene expression, and genome editing. Investigations on this species reveal essential aspects of trochophore body patterning, including organizer signaling, molecular and cellular processes connecting the various developmental functions of the organizer, the specification and behaviors of the endomesoderm and ectomesoderm, and the characteristic dorsoventral decoupling of Hox expression. These findings enrich the knowledge of trochophore body patterning and have important implications regarding the evolution of spiralians as well as bilateral body plans. [ABSTRACT FROM AUTHOR]

Abstract In this article, the in situ grown cobalt nickel bimetallic oxide electrode materials are prepared by hydrothermal method, and the effects of different metal doping on material properties are analyzed. According to the tests, the material after Ti doping has higher capacity, especially for NiCo2O4/Ti0.02 which has the most stable performance. When the current density is 1 mA/cm2, its discharge time is 828 s, the corresponding electrode area specific capacitance is 1.656 F/cm2, and it increase to 2.200 F/cm2 slowly after 1000 cycles of charge and discharge. Furthermore, SEM, XRD, and infrared spectrum tests are conducted toward the materials with good performance. Observed from the SEM figure, the material is in braided rod-shaped and sea urchins spherical structure. Meanwhile, the fact that the formation of crystal structure and the chemical structure of NiCo2O4 are not impacted by Ti doping can be verified by the result obtained from XRD and infrared spectrum test. [ABSTRACT FROM AUTHOR]

Free glutamate is a characteristic amino acid with a fresh taste. A high free glutamate content can increase the flavour of clams and better meet consumer demands. GDH is involved in the production of glutamate from a-ketoglutarate and determines the speed and direction of reaction in the glutamate metabolic pathway. In this study, we cloned a full-length cDNA of MpGDH homologues in the clam Meretrix petechialis and further investigated the relationship among MpGDH gene polymorphisms, gene expression levels, enzyme activity and glutamate content traits. A significant positive correlation of MpGDH gene expression with free glutamate content was observed (r = 0.62, p < 0.05). The relationship of variation in MpGDH gene expression with its SNP genotype and SNP haplotype was assessed. Five SNPs were found to be significantly associated with MpGDH gene expression (p < 0.05), from which we constructed two main haplotypes due to linkage disequilibrium. The results showed that haplotype H2 may be an effective haplotype associated with high MpGDH gene expression and high free glutamate content. The genetic effect of different haplotypes was validated by different family materials, which showed that MpGDH gene expression level of the H1H2 heterozygous genotype were significantly higher than those of the homozygous genotype H1H1 (p < 0.05). In summary, our findings revealed the potential influence of the MpGDH polymorphism on the free glutamate content and provided molecular biological information for the selective breeding of good-quality traits of M. petechialis. • The full-length cDNA sequence of MpGDH has been identified from the clam Meretrix petechialis. • The expression of MpGDH gene was significantly positively correlated with the content of free glutamate. • A significant association between a haplotype and the expression level of MpGDH gene were identified. • The haplotype H2 may be an effective haplotype associated with high MpGDH gene expression and high free glutamate content. [ABSTRACT FROM AUTHOR]

Substantial mortality and economic losses in marine mollusk culture has drawn considerable attention in recent years. The changes in immune status and environmental stress are thought to be the main causes of shellfish summer mortality. The reproduction and immune defense are both physiologically demanding processes, therefore, the immune status of mollusk is likely to be affected by reproduction during breeding. In present study, we performed transcriptome and gene expression analyses in the clam Meretrix petechialis pre-/post-spawning. DEGs enrichment analysis revealed important immune signaling pathways and key genes changed after spawning. Further analysis showed females up-regulated genes involved in apoptosis, TLR signal pathway and heat shock, whereas males down-regulated complement-related genes after spawning. Additionally, both genders of clams up-regulated its immune response level to against Vibrio infection after spawning revealed by the changes of four immune-related DEGs. The up-regulation of two marker genes at the transcription and protein levels further confirmed that pathogen reinforced the expression differences of immune-related genes between the two groups. Our study provides a new insight into the understanding of molecular mechanisms underlying reproduction influenced immune differences in M. petechialis. • Transcriptome and gene expression analyses were performed in the clam Meretrix petechialis pre/post-spawning. • ∙Immune-related genes were up-regulated in females whereas complement-related genes were down-regulated in males after spawning. • ∙Clams up-regulate its immune response level to against Vibrio infection after spawning. [ABSTRACT FROM AUTHOR]

Macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine that mediates both innate and adaptive immune responses. In this study, a homolog of MIF was identified in the clam Meretrix meretrix . Ten SNPs in the DNA partial sequence of MmMIF were found to be significantly associated with Vibrio resistance ( P < 0.05). Distinct expression patterns of MmMIF among different haplotypes were observed after Vibrio challenge. The results showed that haplotypes did not affect MmMIF expression in the negative control group, while the expression of MmMIF in clams with Hap1 and Hap1/Hap2 was significantly lower than that with Hap2 at 24 h in the PBS-injected group but significantly higher than that with Hap2 in the Vibrio- injected group. The results also indicate that Hap1 and Hap1/Hap2 can specifically respond to mechanical stimulation while Hap2 can specifically respond to Vibrio infection. The effect of a missense mutation was detected by site-directed mutagenesis using fusion expression of the protein, which showed that the SNP g.737 (I > V) has no effect on redox activity and tautomerase activity. These studies identified a potential marker that is enriched in Vibrio -resistant clams that can be used for the genetic breeding of Meretrix meretrix . [ABSTRACT FROM AUTHOR]

Serum amyloid A (SAA), an acute response protein as well as an apolipoprotein, is considered to play crucial roles in both innate immunity and lipid metabolism. In this study, a SAA gene ( MmSAA ) was identified in the clam Meretrix meretrix . The full length DNA of MmSAA was 1407 bp, consisting of three exons and two introns. The distribution of MmSAA in clam tissues was examined with the highest expression in hepatopancreas. In response to the Vibrio parahaemolyticus challenge, MmSAA mRNA showed significantly higher expression at 24 h post-challenge in experimental clams ( P < 0.05). Forty-eight single nucleotide polymorphisms (SNPs) in the DNA partial sequence of MmSAA were discovered and examined for their association with Vibrio -resistance and growth traits, respectively. The single SNP association analysis indicated that five single SNPs (g.42, g.72, g.82, g.147 and g.165) were significantly associated with Vibrio -resistance ( P < 0.05). Haplotype analysis produced additional support for association with the Chi-square values 6.393 ( P = 0.012). Among the five selected SNPs, the effect of a missense mutation (g.82, A → G) was detected by site-directed mutagenesis with fusion expression of protein assay, and the result showed that the recombinant plasmids containing wild-type pET30a-MmSAA had more inhibition effect than the mutant ones on the growth rate of the host bacteria. In addition, four growth traits of the clams in 09G3SPSB population were recorded and the SNP g.176 was found to be significantly associated with the growth traits with the Global score value 0.790 ( P = 0.015). Our findings suggested that common genetic variation in MmSAA might contribute to the risk of susceptibility to Vibrio infection and might be associated with the growth traits in the clams M. meretrix , and more works are still needed to validate these SNPs as potential markers for actual selective breeding. [ABSTRACT FROM AUTHOR]

Mesodermal development is essential to explore the interlineage variations in the development of spiralians. Compared with model mollusks such as Tritia and Crepidula, knowledge about the mesodermal development of other molluscan lineages is limited. Here, we investigated early mesodermal development in the patellogastropod Lottia goshimai, which shows equal cleavage and has a trochophore larva. The endomesoderm derived from the 4d blastomere, that is, the mesodermal bandlets, was situated dorsally and showed a characteristic morphology. Investigations of the potential mesodermal patterning genes revealed that twist1 and snail1 were expressed in a proportion of these endomesodermal tissues, while all of the five genes we investigated (twist1, twist2, snail1, snail2, and mox) were expressed in ventrally located ectomesodermal tissues. Relatively dynamic snail2 expression suggests additional roles in various internalization processes. By tracing snail2 expression in early gastrulae, the 3a211 and 3b211 blastomeres were suggested to be the precursors of the ectomesoderm, which elongated to become internalized before division. These results help to understand the variations in the mesodermal development of different spiralians and explore the different mechanisms by which ectomesodermal cells are internalized, which has important evolutionary implications. [ABSTRACT FROM AUTHOR]

Abstract: The influences of ultrahigh pressure (UHP, under 5 GPa) on phase compositions, phase morphologies and hydrogen storage properties of LaMg4Ni alloys were studied. The X-ray diffraction patterns show that the as-cast alloy consists of La2Mg17, LaMg2Ni and Mg2Ni phases, whereas a new LaMg3 phase is observed in the UHP samples in addition to LaMg2Ni and Mg2Ni phases. The scanning electron microscopy graphs indicate that the phase distribution is more homogenous in the UHP alloys than in the as-cast one. Additionally, the microstructure of the UHP alloy heat-treated at 973 K is finer than that at 823 K. Both the reversible hydrogen storage capacity and the plateau of hydrogen pressure of the UHP alloys are close to those of the as-cast one. Of particular interest is that both UHP alloys exhibit better activation properties compared with the as-cast alloy. Moreover, the dehydriding onset temperature of the UHP alloys (5 GPa at 973 K) is about 490 K, which is obviously lower than that of the as-cast alloy. The amount of hydrogen desorption in the UHP alloy (5 GPa at 973 K) is 2.69 wt.% at 573 K, which corresponds to 89.6% of the saturated capacity. However, the corresponding values change to 1.75 wt.% and 58.3% in the as-cast alloy, respectively. It is confirmed the UHP treatment is one of effective approaches to tune the hydrogen storage performances of those rare earth–magnesium–nickel alloys. [Copyright &y& Elsevier]

Abstract: Microstructures and electrochemical characteristics of La0.7Ce0.3Ni4.2Mn0.9−x Cu0.37(Fe0.43B0.57) x (x = 0–0.20) hydrogen storage alloys are investigated. X-ray diffraction and backscattered electron results indicate that the pristine alloy is single LaNi5 phase while the alloys containing Fe0.43B0.57 consist of LaNi5 matrix phase and La3Ni13B2 secondary phase. The relative abundance of La3Ni13B2 phase increases with the increase in x value. The a and V of LaNi5 phase increase with increasing x value. Activation property of the alloy electrodes is improved by substituting Mn with Fe0.43B0.57. Maximum discharge capacity of the alloy electrodes monotonically decreases from 323.3 mAh g−1 (x = 0) to 311.3 mAh g−1 (x = 0.20). Cycling capacity retention rate at the 100th cycle decreases from 79.3% (x = 0) to 68.2% (x = 0.20) with increasing x value, which is ascribed to the degradation of corrosion resistance. High-rate dischargeability of the alloy electrodes first increases with increasing x from 0 to 0.10, and then decreases until x increases to 0.20. It demonstrates that the substitution of Mn with Fe0.43B0.57 is an effective approach to improve the overall electrochemical performances of the Co-free high-Mn alloy electrodes. [Copyright &y& Elsevier]

Abstract: Microstructures and electrochemical characteristics of La0.7Ce0.3Ni4.2Mn0.9−x Cu0.37(V0.81Fe0.19) x hydrogen storage alloys were investigated. X-ray diffraction and scanning electron microscope results indicate that La0.7Ce0.3Ni4.2Mn0.9Cu0.37 alloy is single LaNi5 phase, and the alloys containing V0.81Fe0.19 consist of LaNi5 matrix phase and V–Mn–Ni secondary phase, and the abundance of secondary phase increases with increasing x value. The activation property of the alloy electrodes is improved by increasing V0.81Fe0.19 content. Maximum discharge capacity of the alloy electrodes changes a little with increasing x value. HRD1200 first increases from 60.4% (x =0) to 70.8% (x =0.10), and then decreases to 56.6% (x =0.20). Cycling stability decreases with increasing x from 0 to 0.20. The adequate substitution of Mn by V0.81Fe0.19 can improve overall electrochemical performances of Co-free high-Mn AB5 alloy. [Copyright &y& Elsevier]

Abstract: Microstructures and electrochemical characteristics of LaNi3.55Co0.2−x Mn0.35Al0.15Cu0.75(Fe0.43B0.57) x (x = 0–0.20) hydrogen storage alloys were investigated. X-ray diffraction and Backscatter electron results indicate that the pristine alloy is single LaNi5 phase with CaCu5 type hexagonal structure and the alloys containing Fe0.43B0.57 consist of two phases, matrix LaNi5 phase and La3Ni13B2 secondary phase. The abundance of La3Ni13B2 phase increases with the increase of x value. The a and V of LaNi5 phase increase with increasing x value. Maximum discharge capacity of the alloy electrodes monotonically decreases from 330.0 mA h g−1 (x = 0) to 302.2 mA h g−1 (x = 0.20). High-rate dischargeability of the alloy electrodes first increases with increasing x from 0 to 0.10, and then decreases when x increases to 0.20. Both charge-transfer reaction at the electrode/electrolyte interface and hydrogen diffusion in bulky alloys should be responsible for the high-rate dischargeability. Cycling stability decreases with increasing x from 0 to 0.20. The adequate substitution of Co by FeB can improve the overall electrochemical performances and reduce the raw cost of alloy electrode. [Copyright &y& Elsevier]

Abstract: Microstructures and electrochemical characteristics of La0.7Ce0.3Ni3.75− x Mn0.35Al0.15Cu0.75(V0.81Fe0.19) x (x =0–0.20) hydrogen storage alloys have been investigated. X-ray diffraction patterns and Backscatter electron images indicate that La0.7Ce0.3Ni3.75− x Mn0.35Al0.15Cu0.75(V0.81Fe0.19) x alloys consist of a single phase with CaCu5-type structure. The lattice parameter a and cell volume V increase with increasing x value. Maximum discharge capacity monotonically decreases from 320mAh/g (x =0) to 299mAh/g (x =0.20). The high-rate dischargeability at the discharge current density of 1200mA/g first increases from 52.6% (x =0) to 55.6% (x =0.05), and then decreases to 46.7% (x =0.20). Cycling stability first increases with increasing x from 0 to 0.10 and then decreases when x increases to 0.20, which is resulted from the combined effect of the improvement of the pulverization resistance and the decrease of corrosion resistance. [Copyright &y& Elsevier]

Abstract: Herein, we prepared a new type of magnesium and transition metal-based alloys with the formula of LaMg8.40Ni2.34−x Al x (x =0 and 0.20). Their phase structures, morphologies and hydrogen storage properties were studied by different methods. The XRD patterns show that LaMg8.40Ni2.34−x Al x alloys are made of La2Mg17, LaMg2Ni and Mg2Ni phases. The SEM images indicate that the phase distributions in LaMg8.40Ni2.14Al0.20 alloy are more uniform compared with LaMg8.40Ni2.34 alloy. In addition, the reversible hydrogen storage capacity of LaMg8.40Ni2.14Al0.20 alloy is 3.22wt.% at 558K, which is higher than that of LaMg8.40Ni2.34 alloy. The partial substitution of Al for Ni effectively improves the hydrogen storage capacity, as well as the hydriding/dehydriding kinetics of the alloys, with the evidence that 89% hydrogen in the saturated state in LaMg8.40Ni2.14Al0.20 alloy was released in 1500s at 573K, while only 74% hydrogen in the saturated state in LaMg8.40Ni2.34 alloy was released at the same conditions. Consequently, we believe that the alloying of aluminum in the magnesium-rare earth-transition metal-based alloys can effectively improve their hydrogen storage performance. [Copyright &y& Elsevier]

Abstract: Microstructures and electrochemical characteristics of La0.7Ce0.3Ni3.75−x Cu0.75Mn0.35Al0.15(Fe0.43B0.57) x hydrogen storage alloys have been investigated. X-ray diffraction results indicate that the alloys consist of a single phase with CaCu5-type structure, and lattice parameters c, cell volume V and c/a ratio increase with increasing x value. Maximum discharge capacity of the alloy electrodes first increases from 311.0mAh/g (x =0) to 316.0mAh/g (x =0.15), and then decreases to 311.0mAh/g (x =0.20). High-rate dischargeability at the discharge current density of 1200mA/g first increases from 51.3% (x =0) to 60.7% (x =0.15), and then decreases to 53.6% (x =0.20). Cycling stability first increases with increasing x from 0 to 0.10 and then decreases when x increases to 0.20, which should be ascribed to the improvement of the pulverization resistance and the deterioration of corrosion resistance. [Copyright &y& Elsevier]

Abstract: Microstructure and electrochemical characteristics of La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75−x (Fe0.43B0.57) x hydrogen storage alloys have been investigated. XRD indicates that La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75 alloy consists of a single LaNi5 phase with CaCu5 structure. The alloys containing FeB are composed of LaNi5 phase with CaCu5 structure as matrix phase and La3Ni13B2 phase as secondary phases, and the abundance of the secondary phase gradually increases with increasing FeB content. As x increases from 0.00 to 0.20, maximum discharge capacity of the alloy electrodes monotonically decreases from 314.0 to 290.4mAh/g. Cycling stability of the alloy electrodes increases with increasing x value. High-rate dischargeability at the discharge current density of 1200mA/g first increases from 51.4% (x =0) to 57.2% (x =0.10), and then decreases to 52.7% (x =0.20). The improvement in electrochemical characteristics is ascribed to the secondary phase La3Ni13B2, which improves the electrochemical activity of electrode surface, as well as to the phase boundary in multiphase structure, which decreases the lattice distortion and strain energy and enhances the anti-pulverization property of the alloy electrodes. [Copyright &y& Elsevier]

Abstract: In the present study, a 71.43kDa heat shock protein cDNA was cloned from Asiatic hard clam Meretrix meretrix. The cDNA was 2292bp, containing an open reading frame (ORF) of 1959bp, which encodes a protein of 652 amino acids with a theoretical molecular weight of 71.43kDa and an isoelectric point of 5.32. Based on the amino acid sequence analysis and phylogenetic analysis, this hsp70 cDNA is a member of cytoplasmic hsc70 (constitutive genes) subfamily in the hsp70 family, and is designated as MmeHsc71. Quantitative RT-PCR was carried out to compare the spatial and temporal expression patterns of MmeHsc71 in the mRNA level between control clams and Vibrio parahaemolyticus-infected clams. Spatially, MmeHsc71 mRNA was found in all tested tissues, including foot, hepatopancreas, mantle and gill. MmeHsc71 mRNA expression level in hepatopancreas and gill displayed a significant increase in vibrio-challenged clams at 24h post-infection compared to control clams (P <0.05). Temporally, there was a significant increase of MmeHsc71 mRNA level in hepathopancreas of vibrio-challenged clams compared to control clams at 6, 12, and 24h post-challenge, respectively. The result of quantitative immunofluorescence also indicated that there was obvious increase of MmeHsc71 in hepatopancreas of vibrio-challenged clams compared to control clams in protein level at 24h post-infection. The results suggested that MmeHsc71 may play an important role in mediating the immune responses of M. meretrix to bacterial challenge. [Copyright &y& Elsevier]

Abstract: MM5 was a bacterial strain isolated from moribund clam (Meretrix meretrix) collected from a farm with mass mortality outbreak. Primary genotypic and phenotypic identification including 16S rDNA sequence analysis, multilocus sequence analysis (MLSA) of four housekeeping genes (gapA, ftsZ, mreB and topA) and biochemical tests suggested that strain MM5 was a Vibrio species closest to but different from Vibrio furnissii. Our previous study indicated that MM5 could induce a high mortality of M. meretrix (). Quantitative challenge test was performed in this study to further evaluate the pathogenic potential of MM5, which showed that at 84h post-inoculation, the cumulative mortalities of the MM5-injected group were significantly higher than those of control groups (P <0.05). Cytopathological and histopathological features of the clam infected by MM5 were carried out by transmission electron microscopy (TEM) and Hematoxylin and Eosin (H&E) staining, respectively. Cytopathologically, foci of MM5 were found in hepatocytes of the clam infected by MM5. In addition, cytopathological lesion was detected in foot of infected clam. Histopathologically, MM5 was detected in different tissues of infected clam, including hepatopancreas, mantle and gill. Challenge test combined with pathological features indicated that MM5 was virulent to M. meretrix. [ABSTRACT FROM AUTHOR]

Abstract: Lysozymes function in animal immunity. Three types of lysozyme have been identified in animal kingdom and most lysozymes identified from bivalve molluscs belong to the invertebrate (i) type. In this research, we cloned and sequenced a new i-type lysozyme, named MmeLys, from the Asiatic hard clam Meretrix meretrix. MmeLys cDNA was constituted of 552 bp, with a 441 bp open reading frame encoding a 146 amino acid polypeptide. The encoded polypeptide was predicted to have a 15 amino acid signal peptide, and a 131 amino acid mature protein with a theoretical mass of 14601.44 Da and an isoelectric point (pI) of 7.14. MmeLys amino acid sequence bore 64% identity with the Manila clam (Venerupis philippinarum) i-type lysozyme and was grouped with other veneroid i-type lysozymes in a bivalve lysozyme phylogenetic tree predicted using Neighbor-Jointing method. Recombinantly expressed MmeLys showed lysozyme activity and strong antibacterial activity against Gram positive and Gram negative bacteria. MmeLys mRNA and protein were detected to be mainly produced in hepatopancreas and gill by the methods of semi-quantitative RT-PCR and western blotting. In addition, MmeLys gene expression increased following Vibrio parahaemolyticus challenge. Results of this research indicated that MmeLys represents a new i-type lysozyme that likely functions in M. meretrix immunity. [Copyright &y& Elsevier]

Abstract: This study describes the first introduction of the Peruvian scallop, Argopecten purpuratus (P), from Peru to China. Reciprocal hybridization was carried out between the newly introduced Peruvian scallops and the bay scallops, A. irradians irradians (I). Morphological and molecular evidence indicated that the derived offspring were true hybrids between the two Argopecten scallops. At larval stages, when cultured at 23°C, the growth rates of the hybrid cohorts were not different from that of the inbred bay scallop group but significantly higher than that of the Peruvian scallops. The survival rate of the A. purpuratus ♀× A. irradians ♂ (P♀×I♂) cohort was higher than those of both inbred cohorts but the A. irradians ♀× A. purpuratus ♂ (I♀×P♂) cohort survived better than the bay scallop cohort only. Significant maternal effects were noted on growth rate but not on survival rate. Mating strategy and its interaction with egg origin had significant effects on both growth and survival rates. During the adult grow-out stage, the survival rates of the hybrid cohorts were not different from that of the bay scallops but were much higher than that of the Peruvian scallops. The growth rates in both shell height and whole body weight in the hybrid cohorts were much higher than those of the inbred bay and Peruvian scallop cohorts. Compared with the bay scallops, the production traits in the hybrid cohorts were increased by 125.9–138.9% in whole body weight and by 145.4–156.2% in adductor muscle weight. Thus, although it may not be feasible to culture the Peruvian scallops at a large scale in China, hybridizing the Peruvian scallops with bay scallops may be a very effective way in increasing scallop production in China. [Copyright &y& Elsevier]

The growth and survival of the Zhikong scallop Chlamys farreri suspended in deep water of Haizhou Bay were studied from July 2007 to June 2008, and the biodeposition method was used to estimate the clearance rate of C. farreri under field conditions. Results showed that the scallop grew fast during all the culture time, with the exception of summer. The condition index of the scallop increased with time and reached the highest value in spring of the second year. The survival of scallops was 60.8 ± 3.9% at the end of this study, mortality occurring mainly during the summer and autumn of the first year. The clearance rate fluctuated obviously with season,with the highest value in September 2007, and the lowest value in March 2008. Factors accounting for variations in growth and clearance rate of scallops are also discussed. [ABSTRACT FROM AUTHOR]

Abstract: The Zhikong Scallop, Chlamys farreri, is one of the most important bivalve mollusks cultured in northern China. However, mass mortality of the cultured C. farreri has posed a serious threat to the maricultural industry in recent years. Acute Viral Necrobiotic Virus (AVNV) is believed as an important etiological agent causing the scallop mass mortalities. To understand the mechanism behind the AVNV associated scallop disease and mortality, we assessed the physiological and immune responses of C. farreri to the virus infection using oxygen consumption rate, ammonium-nitrogen excretion rate, hemocyte copper, zinc superoxide dismutase gene expression, and plasma superoxide dismutase activity and alkaline phosphatase activity as indicators. Scallops challenged by AVNV at 25 °C developed typical disease signs 2 days after virus injection. Before the disease manifested, scallop oxygen consumption and NH4 +–N excretion rates rose and then fell back. Real-time PCR revealed that the hemocyte cytosol Cu, Zn SOD gene expression was upregulated followed by recovery. The plasma SOD activity, however, augmented consistently following virus injection. Moreover, plasma AKP activity first lowered and then elevated gradually to the highest level at 24 h post virus injection. Scallops challenged by AVNV at 17 °C neither developed notable disease nor showed obvious responses that could be associated with the virus infection. While the results suggested a correlation between the elevated seawater temperature and the AVNV infection associated C. farreri mortalities, they also indicated that the viral infection provoked multiple physiological and immune responses in the host scallops. [Copyright &y& Elsevier]

Abstract: A mass mortality of clam, Meretrix meretrix, occurred in Jiangsu Province of China in the late September of 2007. Of the isolates obtained from the diseased clams, MM21 had the strongest virulence to the clam in the virulence test, with a LD50 value of ∼6×106 CFUml−1. MM21 was identified as Vibrio parahaemolyticus by the VITEK 2 Compact system and 16S rDNA sequencing. Detection of virulence-associated genes by PCR indicated that MM21 was positive for toxR and tlh, and negative for tdh. Compared with control group, histiocytes from MM21-infected clams displayed a variety of cytopathological changes by transmission electron microscopy examination, which included increased lipid droplets in hepatocytes, deposition of granules in the mantle, excessive secretion in the gill. The results of our study suggested that MM21 may have been an etiological element in the mass mortalities of hard clam (M. meretrix) in Jiangsu Province of China in 2007. [Copyright &y& Elsevier]

Abstract: Shell formation is one of the important events during larval development and metamorphosis in bivalves. However, the molecular mechanisms and environmental cues regulating shell initiation and growth are unclear. Here, we report that ferritin, a principal protein for biological iron storage and metabolism, might play a role in larval shell development of the bivalve mollusk Meretrix meretrix. A full-length ferritin subunit cDNA, named as MmeFer, was cloned and characterized. The MmeFer mRNA expression in different developmental stages, from trochophore to post larvae, was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR). MmeFer mRNA expression in larvae of later developmental stages increased at least 8-fold following trochophores. Moreover, the temporal and spatial expressions of MmeFer mRNA were examined by whole mount in situ hybridization. In the trochophore stage, MmeFer was detectable where it was supposed to be for shell initiation. In the later developmental stages, MmeFer was found near digestive glands and mantle that secret larval shell. MmeFer expression was also detected in larvae cultured in artificial seawater with different iron concentrations ranging from 0 to 100 µM. These results suggest that ferritin may play a role in the shell formation of mollusks. [Copyright &y& Elsevier]

Abstract: Ti45Zr35Ni20−x Pd x (x =0, 1, 3, 5 and 7, at%) alloys were prepared by melt-spinning. The phase structure and electrochemical hydrogen storage performances of melt-spun alloys were investigated. The melt-spun alloys were icosahedral quasicrystalline phase, and the quasi-lattice constant increased with increasing x value. The maximum discharge capacity of alloy electrodes increased from 79mAh/g (x =0) to 148mAh/g (x =7). High-rate dischargeability and cycling stability were also enhanced with the increase of Pd content. The improvement in the electrochemical hydrogen storage characteristics may be ascribed to better electrochemical activity and oxidation resistance of Pd than that of Ni. [Copyright &y& Elsevier]

Abstract: Ti-based icosahedral quasicrystalline phase (I-phase) exhibited excellent hydrogen storage property for special structure. Unfortunately, the application as the negative electrode material of the nickel-metal hydride batteries was limited due to the poor electrochemical kinetics. Meanwhile, rare-earth element was beneficial to the electrochemical properties of Ti, Zr-based alloy. In present work, Ti45Zr30Ni25La x (x =3, 5 and 7) alloys were prepared by melt-spinning. The effect of adding La on the electrochemical performance of melt-spun alloys was investigated in detail. The phase structure of the melt-spun alloys was analyzed by XRD and DSC. The results showed that the amorphous forming ability increased with increasing x value. The maximum discharge capacity decreased from 109mAhg−1 to 99mAhg−1 with increasing x value. High-rate dischargeability and cycling stability were improved by adding La, which may be resulted from the increase of amorphous phase in the alloy electrodes. [Copyright &y& Elsevier]

Abstract: Ti45Zr35Ni13Pd7 alloys are prepared by melt spinning at different cooling rates (v). The phase structure and electrochemical hydrogen storage performance are investigated. When v is 10m/s, the alloy consists of icosahedral quasicrystalline phase (I-phase), C14 Laves phase and a little amorphous phase. When v increases to 20 or 30m/s, a mixed structure of I-phase and amorphous phase is formed. Maximum discharge capacity of alloy electrode decreases from 156mAh/g (v =10m/s) to 139mAh/g (v =30m/s) with increasing v. High-rate dischargeability at the discharge current density of 240mA/g decreases monotonically from 61.2% (v =10m/s) to 56.8% (v =30m/s). Cycling retention rate S 20 increases from 62.2% (v =10m/s) to 66.1% (v =30m/s) with increasing v, which is ascribed to the increase in amorphous phase. [Copyright &y& Elsevier]

Abstract: Ti45Zr30Ni25Y x (x =1, 3, 5 and 7) alloys were prepared by melt-spinning at wheel velocity of 20ms−1. The effect of additive Y on phase structure and electrochemical performance of melt-spun alloys was investigated. Ti45Zr30Ni25Y x melt-spun alloys were composed of I-phase and amorphous phase. The amorphous phase increased with increasing x value, indicating amorphous forming ability improved with increasing Y content. The maximum discharge capacity and high-rate dischargeability decreased with increasing x value, which may be ascribed to the decrease of nickel content. Cycling stability first increased with increasing x from 1 to 3, and then decreased when x increased to 7, which was resulted from the combined effect of the decrease of nickel content and the increase of amorphous phase. [Copyright &y& Elsevier]

Abstract: Seed rearing is an important part in large scale clam culture industry. Since the nutritional history affects early development in bivalve, the condition of larval nutrition plays a key role in successful seed rearing. So far, the molecular mechanism of nutrient uptake in bivalve larvae is unclear. As one of the important proteolytic enzymes, cathepsin B of several organisms has been reported to be involved in digestion. We intended to analyze whether cathepsin B is involved in larval nutrient metabolism in the economic bivalve, clam Meretrix meretrix. The full length of M. meretrix cathepsin B (MmeCB) cDNA was cloned, which is 1647 bp with an open reading frame of 1014 bp. The deduced amino acid sequence encoded a preproenzyme of 337 residues with Cys-114, His-282 and Asn-302 composing cathepsin B activity center. The temporal and spatial expressions of MmeCB mRNA were examined from trochophore to post larva stages by whole mount in situ hybridization. In trochophore stage, no detectable signal was found. In the later three stages, MmeCB mRNA was detected in the digestive gland, suggesting a possible role of MmeCB in digestion. Moreover, MmeCB mRNA was also observed in the epidermal cells in D-veligers. Cathepsin B specific inhibitor (CA074 methyl ester) was applied to block the activity of cathepsin B in unfed larvae. The average shell lengths of treated larvae were smaller than that in control groups. The results of mRNA epidermal distribution and inhibitor treatment in D-veligers indicated that MmeCB may be also associated with other pathway of nutrient metabolism in larval epidermis. The overall results in this paper revealed that MmeCB might play a role in larval nutrient metabolism. [Copyright &y& Elsevier]

Abstract: Melt-spun ribbon and bulk samples in cylindrical rod form with diameter ranging from 2mm to 4mm of Ti40Cu40Zr10Ni10 alloy were prepared by melt-spinning technique and copper mould casting method, respectively. The microstructure, thermal stability and mechanical properties of the bulk samples were investigated. A completely glassy single phase is formed in the 2mm rod sample. Increasing the diameter of the rod samples resulted in the formation of CuTi crystalline phase in the 3mm and 4mm rod samples. The 2mm single glassy rod sample exhibited a large supercooled liquid region ΔT x =58K and γ = T x/(T g + T l) is 0.390, which indicated that the alloy possessed a good glass-forming ability. The bulk samples also exhibited good mechanical properties. The 2mm rod sample showed the highest yield strength of about 2086MPa. The 3mm rod sample not only showed high yield strength of about 2000MPa, but also enhanced plastic strain of about 0.71%. [Copyright &y& Elsevier]

Abstract: Structure and crystallization behavior of amorphous and quasicrystalline Ti45Zr35Ni17Cu3 alloy have been studied. DSC trace of the amorphous alloy obtained during continuous heating to 1300K shows distinctly an exothermic peak and two endothermic peaks. The amorphous alloy has different structures depending on annealing temperature. The first exothermic reaction at low temperature region from 400K to 900K is due to the precipitation of an icosahedral quasicrystalline phase, and the second endothermic reaction at higher temperature region from 950K to 990K results from the transformation of the I-phase to C14 Laves and α-(Ti,Zr) phases. [Copyright &y& Elsevier]

Amorphous and icosahedral quasicrystalline (I-phase) powders were synthesized by mechanical alloying (MA) and subsequent annealing, the phase structure and hydrogen absorption properties of two powders were investigated. XRD analysis indicated that the MAed powder was an amorphous phase and annealed powder was an I-phase. Two alloy exhibited excellent hydrogen adsorption property and started to absorb hydrogen without induction time. PCT measurement showed that the plateau pressure of the amorphous powders was obviously higher than that of the I-phase powders. After the first hydrogen cycling, the partial amorphous phase changed to phases, and the I-phase was steady. Similar hydride phases and were also formed after the second hydrogen cycling for the amorphous and I-phase alloy powders. [Copyright &y& Elsevier]

Abstract: A bulk alloy which consists of the single icosahedral quasicrystalline phase (I-phase) in Ti45Zr35Ni17Cu3 alloy has been fabricated by mechanical alloying and subsequent pulse discharge sintering technique. Crystallographic structure analyses show that the bulk alloy is an I-phase. The transport properties of the bulk alloy are examined, and the results show that the room-temperature thermal conductivity is 5.347WK−1 m−1, and the electrical conductivity decreases with increasing the temperature from 300 to 450K. The Seebeck coefficient is negative at the temperature range from 300 to 360K, and changes to positive from 370 to 450K. Hall effect measurements indicate the bulk I-phase alloy has a high carrier concentration. The specific heat capacity increases when the temperature increases from 280 to 324K. [Copyright &y& Elsevier]

Abstract: Icosahedral quasicrystalline Ti45Zr35Ni17Cu3 alloy was ball-milled with 30mass% La0.9Zr0.1Ni4.5Al0.5 alloy (LaNi5 phase), the effect of the milling time on crystallographic and electrochemical characteristics of the alloy powder was investigated. The amount of amorphous phase increased with increasing milling time from 60 to 360min, and the LaNi5 phase cannot be observed when milling time was 240min or more. The maximum discharge capacity and high-rate dischargeability of milled alloy electrodes were obviously higher than those of the alloy electrode before milling. The cycling capacity retention rate after 40 cycles increased from 52.8% (t =60min) to 62.9% (t =360min). [Copyright &y& Elsevier]

Abstract: Icosahedral quasicrystalline Ti45Zr35Ni17Cu3 alloy powder was ball-milled with 20mass% Ni, and the effect of the ball-milling time (t) on crystallographic and electrochemical characteristics were investigated. The amounts of icosahedral quasicrystalline and Ni phases decreased when ball-milling time increased from 30 to 180min. The powder consisted of amorphous and (Ni and Ti) phases after 360min of ball-milling. The maximum discharge capacity of the powder electrodes first increased from 89 (t =0min) to 192mAhg−1 (t =180min), and then decreased to 138mAhg−1 (t =360min). The high-rate dischargeability and the discharge capacity after 15 cycles increased with increasing ball-milling time. [Copyright &y& Elsevier]

Abstract: Ti45−x Zr35−x Ni17+2x Cu3 (x =0, 2, 4, 6 and 8) icosahedral quasicrystalline phase (I-phase) alloy powders are synthesized by mechanical alloying and subsequent annealing techniques, and the crystallographic and electrochemical characteristics are investigated. The alloy powders are I-phase, and the quasi-lattice constant decreases with increasing x value. The maximum discharge capacity of the I-phase alloy electrodes first increases and then decreases with increasing x value, and the Ti39Zr26Ni29Cu3 I-phase electrode exhibits the highest discharge capacity of 274mAhg−1. The high-rate dischargeability at the discharge current density of 240mAg−1 increases from 55.31% (x =0) to 74.24% (x =8). Cycling stability also increases with increasing x value. The improvement in electrochemical characteristics may be ascribed to the added nickel, which not only improves the electrochemical activity, but also makes the alloy more resistant to oxidation. [Copyright &y& Elsevier]

Abstract: A bulk Ti45Zr35Ni17Cu3 alloy, which consisted of the icosahedral quasicrystalline phase, was prepared by mechanical alloying(MA) and subsequent pulse discharge sintering. Ti45Zr35Ni17Cu3 amorphous powders (with particle size <50μm) were obtained after mechanical alloying for more than 150h from the mixture of the elemental powder. The transformation temperature range from amorphous phase to the quasicrystalline phase was from 400K to 900K. The mechanical properties of the bulk quasicrystalline alloy have been examined at room temperature. The Vickers hardness and compressive fracture strength were 620±40 and 1030±60MPa, respectively. The bulk quasicrystalline alloy exhibited the elastic deformation by the compressive test. The fracture mode was brittle cleavage fracture. [Copyright &y& Elsevier]

Abstract: Ti45Zr35Ni17Cu3 amorphous and single icosahedral quasicrystalline powders were synthesized by mechanical alloying and subsequent annealing at 855K. Microstructure and electrochemical properties of two alloy electrodes were characterized. When the temperature was enhanced from 303 to 343K, the maximum discharge capacities increased from 86 to 329mAhg−1 and 76 to 312mAhg−1 for the amorphous and quasicrystalline alloy electrodes, respectively. Discharge capacities of two electrodes decrease distinctly with increasing cycle number. The I-phase is stable during charge/discharge cycles, and the main factors for its discharge capacity loss are the increase of the charge-transfer resistance and the pulverization of alloy particles. Besides the factors mentioned above, the formation of TiH2 and ZrH2 hydrides is another primary reason for the discharge capacity loss of the amorphous alloy electrode. [Copyright &y& Elsevier]

Abstract: Catecholamines regulate several physiological processes in mollusks. Many pharmacological experiments have been conducted to determine the effects of adrenergic agonist and antagonist of catecholamine receptors on Meretrix meretrix metamorphosis. Results showed that adrenaline (AD) and noradrenaline (NA) had substantial effects (p <0.05) on larval metamorphosis at concentrations ranging from 10 μM to 100 μM. 10 μM β-adrenergic receptor (AR) agonist isoproterenol showed the same inducement effect as that of NA and AD on metamorphosis, whereas the α-AR agonist phenylephrine had no significant effect at concentrations between 0.1 μM and 100 μM concentrations (p >0.05). Furthermore, 1 μM β-AR antagonist propanolol, but not α-AR antagonist prazosin, depressed the larval metamorphosis induced by NA or AD. By immunocytochemistry, two cell bodies of β-adrenergic-like receptor, C/A1, C/A2, were observed in the cerebral/apical ganglion of competent larvae. In addition, there were other immunoreactive dots near C/A1 and C/A2. The results of pharmacology and immunocytochemistry suggests that β-adrenergic-like receptor located in the larval CNS, might play a considerable role in the larval metamorphosis of M. meretrix by AD or NA. [Copyright &y& Elsevier]

Abstract: To determine the optimal larval density for hatchery culture of the clam Meretrix meretrix, experiments with stocking densities of 5, 10, 20, 40 and 60 larvae ml−1 were designed, which included the developmental stages from D-veliger to 8 days post-settlement. Shell length, settlement time and survival rate of the larvae were recorded. Results showed that, at each sampling time, larvae reared at the highest density had the smallest mean size, whereas larvae reared at the lowest density had the largest mean size. Statistical differences in mean shell length at different stocking densities appeared from day 2, and greater differences occurred with increased culture time. Specific growth rate (SGR) in the rapid growing stage (day 0–3) was negatively correlated with density; however, no correlation was found between SGR and density in the slow growing stage (days 3–7). Settlement time was prolonged and shell length of settled larvae decreased as density increased. However, larval survival rate (74.8–79.1%) was independent of stocking density. Results showed that a high stocking density, in the designated range, is feasible for larval culture of the clam M. meretrix. However, for large-scale culture, in the interest of costs and safety, a stocking density of 10–20 larvae ml−1 is recommended. [Copyright &y& Elsevier]

Abstract: Kinetic and electrochemical properties of icosahedral quasicrystalline alloy powder as negative electrode material of Ni–MH battery have been investigated at different temperatures. The calculated results show that the apparent activation enthalpy of the charge-transfer reaction is , and the activation energy of hydrogen diffusion is . The exchange current density and the diffusion coefficient of hydrogen in the bulky electrode increase with increasing temperature, indicating that increasing temperature is beneficial to charge-transfer reaction and hydrogen diffusion. As a result, the maximum discharge capacity, activation property and high-rate dischargeability are greatly improved with increasing temperature. However, the charge retention and the cycling stability degrade with the increase of the temperature. [Copyright &y& Elsevier]

Abstract: Effects of food availability on larval growth and survival of Meretrix meretrix were studied in two experiments by feeding the larvae with different algae diets and by starving the larvae for different periods of time. Newly hatched larvae of M. meretrix were fed with five different marine microalgae species, singly and in various mixtures. Best growth was with Isochrysis galbana as a single species diet. Nutritional value of the other single species diets was in the order of Dunaliella sp.> Phaeodactylum tricornutum > Platymonas subcordiformis > Pavlova viridis. Of the mixtures tested, 50% I. galbana /50% Dunaliella sp., 50% I. galbana /50% P. tricornutum, and 50% I. galbana /50% P. subcordiformis, supported growth and metamorphosis equivalent to those of the I. galbana control. At 25 °C, larvae of M. meretrix were deprived of food for various days to study the growth compensation from the outset of development. The results showed that M. meretrix larvae could survive long feeding delays, and even reach metamorphosis without food added, although starvation had significant effects on growth. These results suggested that M. meretrix larvae had the capacity to survive ‘starvation’ using alternative sources of energy. It also showed that growth, survival and metamorphosis of M. meretrix were affected by many factors besides food quality and quantity. [Copyright &y& Elsevier]

Abstract: Crystallographic and electrochemical characteristics of ball-milled Ti45Zr35Ni17Cu3 + xNi (x =0, 5, 10, 15 and 20mass%) composite powders have been investigated. The powders are composed of amorphous, I- and Ni-phases when x increases from 5 to 20. With increasing x, the amount of Ni-phase increases but the quasi-lattice constant decreases. The maximum discharge capacity first increases as x increases from 0 to 15 and then decreases when x increases further from 15 to 20. The high-rate dischargeability and cycling stability increase monotonically with increasing x. The improvement of the electrochemical characteristics is ascribed to the metallic nickel particles highly dispersed in the alloys, which improves the electrochemical kinetic properties and prevents the oxidation of the alloy electrodes, as well as to the mixed structure of amorphous and icosahedral quasicrystalline phases, which enhances the hydrogen diffusivity in the bulk of the alloy electrodes and efficiently inhibits the pulverization of the alloy particles. [Copyright &y& Elsevier]

Abstract: This study systematically analyzes long-term (1950–1992) stream temperature records for the major sub-basins within the Lena River watershed in order to describe water temperature regimes over the various parts of the Lena watershed and document significant stream temperature changes induced by reservoir regulation, and by natural variations/changes. The results show that the open water season can be divided into three consecutive stages—“increasing temperature stage” in the early open water season, “stable temperature stage” in the mid-warm season, and “decreasing temperature stage” in the late open water season. Temperature conditions are similar over the Aldan and Upper Lena regions. However, stream temperatures at the Lena basin outlet are up to 8 °C lower than those over the southern sub-basins. This suggests that the latitudinal difference in climatic variables, such as air temperature, might be the major control on stream temperature regime. Results also demonstrate that the reservoir regulation has a strong influence on the regional water temperature regime and change in the regulated sub-basin. Reservoir regulation has increased (decreased) the downstream water temperatures in the Vilui valley during the early (mid) open water season. Trend analyses show consistent warming trends across the entire Lena River basin in the early open water season. This may indicate a response to earlier snowmelt over the Lena River watershed. Trend results also demonstrate that the Aldan tributary, without much human impact, experiences warming (cooling) trends in the first (second) half of the open water season, leading to a stream temperature regime shift toward early open water season. The upper Lena River has warming (cooling) trends in the early (mid-late) open water season. Over the regulated Vilui tributary, however, stream temperatures have significantly increased in the early and late parts of the warm season due to combined effects of natural changes and reservoir regulation. Over the Lena basin as a whole, strong positive correlations have been found between the basin mean monthly air and water temperatures during the warm season. Increasing water temperatures were observed during the early and mid-June. Because of stream temperature increase in this peak flow period, the Lena River heat flux has gone up by 23% in June. This may have considerable impact on the thermal conditions of the Laptev Sea in the early summer season. [Copyright &y& Elsevier]

• We linked weight perception to depressive symptoms in Chinese college students. • Overall, perceived overweight was related to significant depressive symptoms. • Overall, perceived underweight was related to depressive symptoms only in men. • In subsample BMI < 18.5, an over-perception increased depression risks for women. • In subsample BMI ≥ 25, perceived normal-weight lowered depression risks for men. Depressive disorder among college students is a prominent issue. Recent evidence indicates that body weight perception (BWP) is, in addition to body mass index (BMI), associated with mental health in adolescents. This study used data from a large-scale, national survey of college students in China to examine the overall relationship between BWP and depressive symptoms and its variation across BMI-classified subgroups: the underweight (BMI < 18.5), the normal-weight (18.5 ≤ BMI < 25), and the overweight (BMI ≥ 25). Depressive symptoms were evaluated using a 10-item version of the Center for Epidemiologic Studies-Depression (CES-D). BWP was measured by asking "What do you think of your weight status?" Response options include "underweight", "normal weight", and "overweight". In both the overall sample and the normal-weight subsamples, perceived overweight was linked to significant depressive symptoms for men and women, while perceived underweight was linked to depressive symptoms only in men. In the underweight subsample, perceived normal-weight or overweight was associated with depressive symptoms for women. In the overweight subsample, perceived normal-weight was associated with a lower level of depressive symptoms for men. The results showed the importance of BWP in predicting depressive symptoms of college students. In-campus health education programs tailored to differential BMI and gender groups can be specifically designed to improve the psychological wellbeing of young adults. [ABSTRACT FROM AUTHOR]

Hydrolysis of ammonia borane (NH3BH3, AB) involves multiple undefined steps and complex adsorption and activation, so single or dual sites are not enough to rapidly achieve the multi‐step catalytic processes. Designing multi‐site catalysts is necessary to enhance the catalytic performance of AB hydrolysis reactions but revealing the matching reaction mechanisms of AB hydrolysis is a great challenge. In this work, we propose to construct RuPt−Ti multi‐site catalysts to clarify the multi‐site tandem activation mechanism of AB hydrolysis. Experimental and theoretical studies reveal that the multi‐site tandem mode can respectively promote the activation of NH3BH3 and H2O molecules on the Ru and Pt sites as well as facilitate the fast transfer of *H and the desorption of H2 on Ti sites at the same time. RuPt−Ti multi‐site catalysts exhibit the highest turnover frequency (TOF) of 1293 min−1 for AB hydrolysis reaction, outperforming the single‐site Ru, dual‐site RuPt and Ru−Ti catalysts. This study proposes a multi‐site tandem concept for accelerating the dehydrogenation of hydrogen storage material, aiming to contribute to the development of cleaner, low‐carbon, and high‐performance hydrogen production systems. [ABSTRACT FROM AUTHOR]

An excellent turnover frequency of 1072 min−1 toward H 2 production from ammonia borane hydrolysis is achieved on V doping Ru/Ti 2.5 V 0.5 C 2 catalyst. The enhancive interaction between two active centers of Ru* and Ti 2.5 V 0.5 C 2 * via the doped V atoms is responsible for activation of ammonia borane and water molecules on Ru/Ti 2.5 V 0.5 C 2 catalyst, respectively. [Display omitted] • The doped V atom enhances the electron-feeding effect of support on Ru. • The dissociation energy at both active centers is reduced by the doped V atom. • The V-doped catalyst shows a turnover frequency of 1072 min−1. Designing and constructing the active center of Ru-based catalysts is the key to efficient hydrolysis of ammonia borane (NH 3 BH 3 , AB) for hydrogen production. Herein, V-doped Ru/Ti 2.5 V 0.5 C 2 dual-active center catalysts were synthesized, showing excellent catalytic ability for AB hydrolysis. The corresponding turnover frequency value was 1072 min−1 at 298 K, and the hydrolysis rate r B of AB was 235 × 103 mL·min−1·g Ru –1. X-ray photoelectron spectroscopy results indicated that the interaction between V-doped Ti 3 C 2 and catalytic metal Ru transfers electrons from Ti to Ru, resulting in electron-rich Ru species. According to density functional theory calculations, the activation energy and reaction dissociation energy of the reactants AB and H 2 O on V-doped catalysts were lower than those of Ru/Ti 3 C 2 , thus optimizing the catalytic kinetics of AB hydrolysis. The modification strategy of V-doped Ti 3 C 2 provides a new pathway for the development of high-performance catalysts for AB hydrolysis. [ABSTRACT FROM AUTHOR]

Clean and sustainable hydrogen production through liquid hydrogen storage material requires highly active and stable earth‐abundant non‐noble metal to replace expensive and rare noble metals. Herein, nickel nanofilms (Ni/NiO‐NFs) were prepared by the ionic liquid/water interface route. The cationic carbon chain length of the ionic liquid affects the phase composition of the nickel nanofilm, and the ionic liquid with [OMIm][PF6] as the anion has good thermal stability during the synthesis process. The efficiency of Ni/NiO‐NFs catalysts was tested by comparative kinetic analysis of the AB hydrolysis for hydrogen production. The as‐prepared Ni/NiO‐NFs catalyst exhibits excellent hydrogen generation performances, including a hydrogen production rate (2917 ml min−1 gNi−1), and a low activation energy (48.1 kJ/mol). The transition of nickel oxide to metallic nickel and the destruction of the catalyst structure is responsible for the decreased durability. This work highlights the significance of amorphous nanofilms catalysts via the ionic interface method on the regulation of activity for AB hydrolysis. [ABSTRACT FROM AUTHOR]

Lowering the dehydrogenation temperature and maintaining high dehydrogenation capacity are greatly hindering the practical application of α-AlH 3 for the hydrogen fuel cell industry. Herein, the layered accordion-like V 2 C MXene is synthesized and doped into α-AlH 3 by mild ball milling. The 1 wt.% V 2 C-catalyzed α-AlH 3 possesses excellent dehydrogenation performance with a low initial decomposition temperature of 70.5 °C and a high hydrogen release capacity of 8.1 wt.%. Furthermore, 7.8 wt.% of hydrogen could be quickly released from α-AlH 3 -1 wt.% V 2 C composite within 15 min at 120 °C, with a lower activation energy of 69.5 kJ/mol than that of as-received sample. The excellent dehydrogenation performance is attributed to the high activity of the zero valence V catalyst which is transformed from the multivalent V during ball milling and to promote dissociation and reorganization of hydrogen. This effective approach significantly enhances the dehydrogenation of α-AlH 3 , providing a hopeful approach for modifying metal hydrides. • V 2 C MXene was firstly used to catalyze the dehydrogenation of α-AlH 3. • The α-AlH 3 -1 wt.% V 2 C composites showed excellent desorption performance. • The vanadium metal (V0) plays a catalytic role. [ABSTRACT FROM AUTHOR]

Single‐atom alloys (SAAs), combining the advantages of single‐atom and nanoparticles (NPs), play an extremely significant role in the field of heterogeneous catalysis. Nevertheless, understanding the catalytic mechanism of SAAs in catalysis reactions remains a challenge compared with single atoms and NPs. Herein, ruthenium‐nickel SAAs (RuNiSAAs) synthesized by embedding atomically dispersed Ru in Ni NPs are anchored on two‐dimensional Ti3C2Tx MXene. The RuNiSAA‐3−Ti3C2Tx catalysts exhibit unprecedented activity for hydrogen evolution from ammonia borane (AB, NH3BH3) hydrolysis with a mass‐specific activity (rmass) value of 333 L min−1 gRu−1. Theoretical calculations reveal that the anchoring of SAAs on Ti3C2Tx optimizes the dissociation of AB and H2O as well as the binding ability of H* intermediates during AB hydrolysis due to the d‐band structural modulation caused by the alloying effect and metal‐supports interactions (MSI) compared with single atoms and NPs. This work provides useful design principles for developing and optimizing efficient hydrogen‐related catalysts and demonstrates the advantages of SAAs over NPs and single atoms in energy catalysis. [ABSTRACT FROM AUTHOR]

Single‐atom alloys (SAAs), combining the advantages of single‐atom and nanoparticles (NPs), play an extremely significant role in the field of heterogeneous catalysis. Nevertheless, understanding the catalytic mechanism of SAAs in catalysis reactions remains a challenge compared with single atoms and NPs. Herein, ruthenium‐nickel SAAs (RuNiSAAs) synthesized by embedding atomically dispersed Ru in Ni NPs are anchored on two‐dimensional Ti3C2Tx MXene. The RuNiSAA‐3−Ti3C2Tx catalysts exhibit unprecedented activity for hydrogen evolution from ammonia borane (AB, NH3BH3) hydrolysis with a mass‐specific activity (rmass) value of 333 L min−1 gRu−1. Theoretical calculations reveal that the anchoring of SAAs on Ti3C2Tx optimizes the dissociation of AB and H2O as well as the binding ability of H* intermediates during AB hydrolysis due to the d‐band structural modulation caused by the alloying effect and metal‐supports interactions (MSI) compared with single atoms and NPs. This work provides useful design principles for developing and optimizing efficient hydrogen‐related catalysts and demonstrates the advantages of SAAs over NPs and single atoms in energy catalysis. [ABSTRACT FROM AUTHOR]