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We report a stable, water-soluble, mononuclear manganese(IV) complex [Mn

Aquaculture accounts for about 70% of global aquatic products, and viral diseases severely harm the development of aquaculture industry. Spring viremia of carp virus (SVCV) is the pathogen causing highly contagious spring viremia of carp (SVC) disease in cyprinids, especially common carp ( Cyprinus carpio ), yet neither a vaccine nor effective therapies are available to treat this disease.

Two metal–organic frameworks, [Me(n-Bu)3P][Mn(dca)3] (1) and (Et4P)[Mn(dca)3] (2) (dca: N(CN)2–, dicyanamide), exhibit perovskite-like (ABX3) three-dimensional structures. Two phosphonium cations o...

A heterometallic Cu-Ln dinuclear compound [(Me2CO)Cu(L)Dy(NO3)3] (1) (L = chiral Schiff base ligand) has been synthesized and structurally characterized. Employing the dinuclear compounds as second...

Two new homo chiral Cu–Ln (Ln = Gd and Ho) compounds bearing a chiral Schiff base ligand (1R,3S)-N′,N′′-bis[3-methoxysalicylidene]-1,3-diamino-1,2,2-trimethylcyclopentane (H2L) have been synthesized and characterized by elemental analysis, IR spectroscopic and single-crystal X-ray diffraction techniques. The compounds were found to exhibit 1D zig-zag skeletons with double μ-1,5 bridging dicyanamide anions. Circular dichroism (CD) spectra have been used to verify their chiroptical activities. Magnetic studies suggest that 1 and 2 hold the same magnetic behavior with the dinuclear compounds presenting ferromagnetic interaction. Furthermore, both compounds show ferroelectricity with the remnant polarization (Pr) value of 0.23 and 0.18 μC cm−2 at room temperature, respectively.

In order to derive a method for estimating the strength coefficient and strain hardening exponent of steel, the performance parameters of 86 kinds of steel taken from American Iron and Steel Institute (AISI) Bar Steel Fatigue Database were examined and equations that related the strength coefficient and strain hardening exponent to the ultimate tensile strength and yield strength were developed. Correlations from the literature among the strength coefficient, strain hardening exponent and other monotonic tensile properties were also examined and compared to the relationships proposed in this study using the data of 86 kinds of steel. The proposed method was shown to be better used to estimate the strength coefficient and strain hardening exponent.

Three silver compounds with the formulas: [Ag2(HL1)] (1), [Ag10(L2)2(H2O)1.25] (2), and [Ag5(L3)]·1.5H2O (3) were obtained by self-assembly of silver nitrate with 4,4′-phosphinicobis-dibenzoic acid...

Eight novel coordination polymers were prepared by a tripodal ether-linked tricarboxylic acid: [Mn3(TCMB)2(H2O)4]n·4nH2O (1), [Cu3(TCMB)(μ3-OH)3]n·0.5nH2O (2), [Zn3.5(TCMB)2(μ2-OH)(H2O)4]n·2nH2O (3...

Two novel coordination polymers have been hydrothermally synthesized by reactions of Cu(II) salt with 2,2′-phosphinico-dibenzoic acid (H3L), namely, [Cu6L4(H2O)10]·8H2O (1) and [Cu3L2(4,4′-bipy)2(H2O)2] (2). Both compounds were well characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopic, powder X-ray diffraction and thermal analyses. Compound 1 crystallizes in a noncentrosymmetric monoclinic Pc space group and presents a ladder-like chain structure. In the structure of 1, Cu6 ions are attached to one side of the ladder through carboxylate group generating a novel noncentrosymmetric chain. Magnetic studies indicate that compound 1 exhibits a typical ferrimagnetic behavior. Compound 2 crystallizes in a monoclinic P21/c space group and presents a three-dimensional framework architecture. Compounds 1 and 2 show catalytic activities for the degradation of methylene blue in aqueous solution.

Five new coordination polymers based on 5,5′-(1,2-phenylenebis(methoxy))diisophthalic acid (H4L), namely [Co3(HL)2(phen)2]n·2nH2O (1), [Mn2L(phen)2]n·2nH2O (2), [Cu2L(4-abpt)2(H2O)2]n·2nDMF (3), [Co2L(bpp)2(H2O)3]n·3nH2O (4) and {(CH3)2NH2[Co2L(μ3-OH)(H2O)2]·DMF·H2O}n (5) (4-abpt = 4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole, bpp = 1,3-bis(4-pyridyl)propane, phen = 1,10-phenanthroline), have been synthesized and characterized by elemental analyses, IR spectra, PXRD, thermogravimetry and X-ray structural analysis. Complex 1 is a 2D coordination polymer constructing from hexadentate HL3− ligand, which contains trinuclear cobalt cluster [Co3(COO)6] building block. Complex 2 is a 2D coordination polymer assembled by octadentate L4− ligand. Complex 3 is a 3D metal-organic framework assembled by tetradentate L4− ligand and 4-abpt linker. Complex 4 exhibits a 2D layered network containing 1D [Co2L]n nanotube. Complex 5 is a 2D coordination polymer possessing tetranuclear cobalt cluster Co4(μ3-OH)2(COO)4. Tetracarboxylate exhibits five types of coordination modes. Thermal analyses demonstrate that complexes 1 and 2 were thermal stable up to 400–450 °C. Variable-temperature magnetic studies indicate that complex 1 has ferrimagnetic coupling in the [Co3(COO)6] cluster. Complexes 2 and 5 present antiferromagnetic interactions.

Two 3D coordination polymers with the formulas: [Mn(HL)(H2O)]·0.5H2O (1) and [Cu3(L)2(H2O)2]·2H2O (2), were harvested by self-assembly of Mn(II) and Cu(II) metal ions with 4,4′-phosphinicobis-dibenzoic acid (H3L) through solvothermal process. With various characterization methods, their structures were confirmed. Both 1 and 2 crystallize in the monoclinic P21/c space group. In 1, each quadrangular tube links four other ones by phosphinates to produce a porous three-dimensional (3D) framework. Compound 2 contains the inorganic chains formed by paddle-wheel [Cu2(COO)4] unit and Cu(II) ions in alternate arrangement concatenated by phosphinates. Those chains grow up to a 3D network with the total accessible volume being 49.2% per unit cell volume. Magnetic analysis reveals that 1 and 2 display antiferromagnetic behavior.

The Legionella pneumophila effector MavC is a transglutaminase that carries out atypical ubiquitination of the host ubiquitin (Ub)‐conjugation enzyme UBE2N by catalyzing the formation of an isopeptide bond between Gln40Ub and Lys92UBE2N, which leads to inhibition of signaling in the NF‐κB pathway. In the absence of UBE2N, MavC deamidates Ub at Gln40 or catalyzes self‐ubiquitination. However, the mechanisms underlying these enzymatic activities of MavC are poorly understood at the molecular level. This study reports the structure of the MavC–UBE2N–Ub ternary complex representing a snapshot of MavC‐catalyzed crosslinking of UBE2N and Ub, which reveals the way by which UBE2N–Ub binds to the Insertion and Tail domains of MavC. Based on the structural and experimental data, the catalytic mechanism for the deamidase and transglutaminase activities of MavC is proposed. Finally, by comparing the structures of MavC and MvcA, the homologous protein that reverses MavC‐induced UBE2N ubiquitination, several essential regions and two key residues (Trp255MavC and Phe268MvcA) responsible for their respective enzymatic activities are identified. The results provide insights into the mechanisms for substrate recognition and ubiquitination mediated by MavC as well as explanations for the opposite activity of MavC and MvcA in terms of regulation of UBE2N ubiquitination., The pathogen Legionella pneumophila evades immune detection by deploying the transglutaminase effector MavC to ubiquitinate the host ubiquitin‐conjugating enzyme UBE2N. This work presents the structure of MavC–UBE2N–Ub ternary complex and sheds light on the molecular basis for MavC‐induced transglutamination and its mechanistic differences with its homolog MvcA, which counteracts MavC activity by deubiquitinating modified UBE2N in later phases of infection.

Spring viremia of carp virus (SVCV) is a highly pathogenic Vesiculovirus in the common carp. The phosphoprotein (P protein) of SVCV is a multifunctional protein that acts as a polymerase cofactor and an antagonist of cellular interferon (IFN) response. Here, we report the 1.5-Å-resolution crystal structure of the P protein central domain (P(CD)) of SVCV (SVCV(PCD)). The P(CD) monomer consists of two β sheets, an α helix, and another two β sheets. Two P(CD) monomers pack together through their hydrophobic surfaces to form a dimer. The mutations of residues on the hydrophobic surfaces of P(CD) disrupt the dimer formation to different degrees and affect the expression of host IFN consistently. Therefore, the oligomeric state formation of the P protein of SVCV is an important mechanism to negatively regulate host IFN response. IMPORTANCE SVCV can cause spring viremia of carp with up to 90% lethality, and it is the homologous virus of the notorious vesicular stomatitis virus (VSV). There are currently no drugs that effectively cure this disease. P proteins of negative-strand RNA viruses (NSVs) play an essential role in many steps during the replication cycle and an additional role in immunosuppression as a cofactor. All P proteins of NSVs are oligomeric, but the studies on the role of this oligomerization mainly focus on the process of virus transcription or replication, and there are few studies on the role of P(CD) in immunosuppression. Here, we present the crystal structure of SVCV(PCD). A new mechanism of immune evasion is clarified by exploring the relationship between SVCV(PCD) and host IFN response from a structural biology point of view. These findings may provide more accurate target sites for drug design against SVCV and provide new insights into the function of NSV(PCD).

A chiral porous 3D metal-organic framework (MOF) is constructed from an enantiopure carboxylate ligand of 1,1'-biphenol, which can be utilized as adsorbent for the separation of aromatic alcohols and sulfoxides with enantioselectivity of up to 99.4%. Single-crystal X-ray diffraction analysis reveals the binding sites and host-guest interactions clearly, providing microscopic insight into the origin of the enantiosorption in the framework.

Employing polynuclear cluster-based nodes can make metal–organic frameworks have higher porosity and good stability. In this work, by using compound [(Me2NH2)Eu(L)(DMA)(H2O)]n (1) as reactant, polynuclear cluster-based [(Me2NH2)Eu5(L)4(DMA)4(H2O)6]n (2) (H4L = 1,3-bis-[3,5-bis(carboxy)phenoxy]propane) can be synthesized successfully. Although two compounds are all three-dimensional microporous anionic frameworks, the water-stability and porosity of compound 2 is higher than that of compound 1. Compound 2 is assembled by two kinds of multinuclear metal units in which one Eu(III) ion center is hexa-coordinated. The luminescence studies exhibited that compound 2 performed a highly selective photoluminescence quenching toward nitrobenzene and Fe(III) ion. So, compound 2 can be possibly developed as a dual functional chemosensor for detecting Fe(III) ion and nitrobenzene. Furthermore, compound 2 also has the potential ability to absorb and remove toxic metal ions from aqueous solution.

The solution reactions of metal salts with (+)-dibenzoyl-tartaric acid (H2L) and 1,3-bis(4-pyridyl)propane (bpp) or 4,4′-bipyridine (4,4′-bipy) afford three two-dimensional (2D) coordination polymers, [Mn2L2(bpp)2(H2O)4]n·nH2O (1), [CuL(bpp)]n·nH2O (2) and [CoL(4,4′-bipy)(CH3OH)(H2O)]n (3). Dibenzoyl-tartrate ligand displays cis- or trans-conformation, and acts as a 1,4-dicarboxylate linker. Complex 1 features a beautiful 2D double-layered (4,4) network containing [Mn4L2(bpp)4] tetrahedral cage. The flexible bpp ligand links Mn(II) to form an interesting 64-membered saddle-shaped macrocycle [Mn4(bpp)4]. Complex 2 displays a 2D wave-like network assembled by 1D [CuL]n linear chain and 1D [Cu(bpp)]n zigzag chain. Complex 3 is a 2D layered network constructing from [CoL(CH3OH)(H2O)]n chain and [Co(4,4′-bipy)]n chain.

Interferon (IFN) is a vital antiviral factor in host in the early stages after the viral invasion. Meanwhile, viruses have to survive by taking advantage of the cellular machinery and complete their replication. As a result, viruses evolved several immune escape mechanisms to inhibit host IFN expression. However, the mechanisms used to escape the host's IFN system are still unclear for infectious hematopoietic necrosis virus (IHNV). In this study, we report that the N protein of IHNV inhibits IFN1 production in rainbow trout by degrading the MITA. Firstly, the upregulation of IFN1 promoter activity stimulated by poly I:C was suppressed by IHNV infection. Consistent with this result, the overexpression of the N protein of IHNV blocked the IFN1 transcription that was activated by poly I:C and MITA. Secondly, MITA was remarkably decreased by the overexpression of N protein at the protein level. Further analysis demonstrated that the N protein targeted MITA and promoted the ubiquitination of MITA. Taken together, these data suggested that the production of rainbow trout IFN1 could be suppressed by the N protein of IHNV via degrading MITA.

A 14-day experiment was conducted to explore the pathological process and immune response of soybean meal (SBM) induced enteritis (SBMIE) in grass carp (Ctenopharyngodon idellus). The complete replacement of dietary fish meal (FM) with SBM resulted in a remarkable reduction in final body weight, weight gain ratio, and feed conversion efficiency (p < 0.05). The typical histopathological changes of SBMIE appeared starting at day 4, and progressively increased in severity until day 8, then gradually subsided after day 11. The course of SBMIE could be divided into incubation period (days 1-2), prodromal period (days 3-6), symptomatic period (days 7-10), and convalescent period (days 11-14). Transcription levels of pro-inflammatory cytokines, including IL-1β, TNF-α, IL-6, IL-8, IL-17A/F1 and IFN-γ2, were up-regulated during the prodromal period, and then down-regulated during the convalescent period. Transcript levels of anti-inflammatory cytokines (IL-10 and TGFβ1) and their receptors (IL-10R1 and TβRII), were up-regulated during the prodromal and convalescent periods. Transcript levels of MHCIIβ, Igμ, Igτ, TCRδ, TCRβ, CD4, and CD8α were altered in SBMIE. Furthermore, expression levels of T-bet, IFN-γ2, RORγ2 and IL-17A/F1 were significantly increased in the initiation of enteritis, whereas the transcript levels of Foxp3 and IL-2/15Ra were significantly up-regulated in the repair of enteritis. In conclusion, grass carp SBMIE is regulated by the adjustment of SBM-based diet intake, and the changes of the above-mentioned genes expression suggest that these genes may be involved in SBMIE.

A new octacyanotungstate(V) based single chain magnet {[(Tpm)Co(DMF)W(CN)8]2[Co(DMF)4]·2DMF}n (1, Tpm = 1,1,1-trispyrazoylmethane), with an effective barrier of 39.7(3) cm−1 is reported. The Ising-like magnetic anisotropy of the chain originates from the nearly parallel local orientations of the Co(II) ions with the source of the uniaxial magnetic anisotropy being a trigonal distortion of the octahedral environment with the fac-tridentate capping Tpm ligand.

A novel copper metal–organic framework (MOF) [Cu3L2(H2O)2.75]·0.75H2O·1.75DMA (H3L = 4-(2-carboxyphenoxy)-isophthalic acid, DMA = dimethylacetamide) has been synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction. Compound 1 shows a three-dimensional architecture with a sqc topology net where the [Cu2(COO)4] unit was viewed as a node. Magnetic studies indicate that strong antiferromagnetic coupling with J = −159.0(9) cm–1 dominates in the compound. As a sensor, the compound based on quartz crystal microbalance (QCM) exhibits good linearity humidity sensing properties after being exposed to various relative humidity environments at room temperature. The resulting sensitivity is about 28.7 Hz/%RH with a good linearity coefficient of 0.993.

Nine Cu(I)-cyanide metal–organic frameworks (MOFs), namely, [Cu4(CN)2(4-bpt)2]n (1), {[Cu3(CN)2(4-bpt)]·H2O}n (2), [Cu2(CN)(3-bpt)]n (3), [Cu2(CN)2(3-Hptz)]n (4), [Cu3(CN)2(3-ptz)]n (5), [Cu7(CN)7(3-tpt)2]n (6), {[Cu9(CN)9(btb)2]·btb}n (7), [Cu2(CN)2(4-azpy)]n (8), and [Cu3(CN)3(bpp)]n (9) (4/3-Hbpt = 3,5-bis(4/3-pyridyl)-1,2,4-triazole; 3-Hptz = 3-pyridyl-tetrazole; 3-tpt = 2,4,6-tris(3-pyridyl)-1,3,5-triazine; btb = 1,4-bis(1,2,4-triazol-4-yl)benzene; 4-azpy = 4,4′-azobispyridine; bpp = 1,3-bis(4-pyridyl)propane), were synthesized under hydrothermal conditions and structurally characterized. The 4-bpt, 3-bpt, and 3-Hptz ligands in 1–4 were in situ generated by cycloaddition reactions. Their structural features vary from two-dimensional (2D) (3), three-dimensional (3D) (4, 5, 6), 3D 2-fold interpenetration (1, 2, 8), to 3D 3-fold interpenetration (7, 9). Complex 1 is an intriguing 3D metal–organic framework (MOF) with a nanosized rectangular channel. Complex 3 exhibits a chiral 2D double-layered network ...

Six hydrous Cd(II) coordination polymers based on a scorpion-like 5-(3-pyridylmethoxy)isophthalic acid (H2L), namely {[CdL(H2O)]·2H2O}n (1), [Cd4L4(H2O)4]n (2), [CdL(H2O)]n (3), [CdL(H2O)2]n (4), {[CdL(H2O)]·H2O}n (5) and [CdL]n (6), were hydrothermally synthesized and characterized by EA, IR, PXRD, TG-DSC and X-ray structural analysis. Temperature and solvent play crucial roles in the preparation of the coordination polymers. Complexes 1–3 were prepared in a H2O-DMF (6:2) solvent system at slightly different temperature (85, 100 and 120 °C). Complexes 4–6 were prepared in different H2O-DMF solvents (6:3 and 8:2) and H2O-MeCN (3:6) solvent. These complexes possess different coordinated and/or lattice water molecules, and exhibit structural diversity and various topology nets. Complex 1 is a 2D double-layered coordination polymer. Complex 2 features a 3D porous framework with irl topology. Complex 3 displays a 2D double-layered network. Complex 4 is a 3D coordination polymer with sra topology. Complex 5 exhibits a 3D wave-like framework with sra topology. Complex 6 is a 3D coordination polymer with self-catenated hxg-d topology. 5-(3-Pyridylmethoxy)isophthalate adopts three types of coordination modes. These complexes exhibit higher thermal stability and emit strong luminescence.

Triaxial vibration tests can realistically simulate the vibration environment suffered by products. In this paper, an equivalent shape-preserving clipping method for the control spectrum is proposed to avoid over-testing of triaxial random vibration. Considering synchronous response control of the triaxial vibration, the correlative triaxial random load identification model is built to implement the designated triaxial random vibration test. Then, with the goal of avoiding over-testing of triaxial random vibration, a clipping method following four kinds of clipping criteria is studied based on stress equivalence to the key components. Further, to be consistent with the key indicators of the control spectrum in the current uniaxial vibration test specification, a shape-preserving regulation is proposed for determining the triaxial vibration control spectrum. Finally, the effectiveness of the proposed method is verified by taking a typical spacecraft cabin as the example.

Three copper(I) cyanide coordination polymers, namely [Cu8(CN)8(btmb)2]n (1), [Cu(CN)(btmb)0.5]n (2) and [Cu2(CN)2(dpa)]n (3) (btmb = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, dpa = di(4-pyridyl)amine), were synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectra, PXRD and thermogravimetric analyses. Single-crystal X-ray diffraction analyses reveal that complex 1 is an interesting 2D double-layered network constructing from eight distinct Cu(I) centers, eight μ2-cyanides and two tetradentate cis-btmb ligands. Complex 2 is a ladder-like coordination polymer assembled by CuCN linear chain and bidentate trans-btmb linker. Complex 3 has a 2D wave-like network constructing from CuCN zigzag chain and V-shape dpa spacer. These coordination polymers are thermally stable up to 270–300 °C. They emit blue luminescence originating from ligand-centered emission.

Two coordination polymers, [Cu(SCN)(3-ptz)]n (1) and [Cu(SCN)(btmb)]n·nCH3CN (2) (3-ptz = 5-(3-pyridyl)tetrazole, btmb = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene), were synthesized and characterized by EA, IR, PXRD and thermogravimetry. Complex 1 is a 2-D coordination polymer constructed from bidentate 3-ptz and 1,3-thiocyanate ligands. Complex 2 is a 2-D wave-like coordination polymer assembled by bidentate btmb and 1,3-thiocyanate ligands. Acetonitrile guest molecule is perched in the tunnel. Complexes 1 and 2 remain stable up to 240°C and 280°C, respectively. Complex 1 emits strong orange luminescence at 590 nm, and complex 2 emits blue luminescence at 468 nm.

The effects of serials of electric parameters (i.e. electric pulsed current, electric pulse width, etc.) on machining speed and surface quality were investigated. Furthermore the selected parameters in electrical discharge machining (EDM) were optimized. Experiments indicate that the machining speed of EDM increases with the increasing of pulse current and pulse width. On the other side, the surface quality decrease with the increasing of pulse current and pulse width.

Spring viremia of carp virus (SVCV) is an efficient pathogen causing high mortality in the common carp. Fish interferon (IFN) is a powerful cytokine enabling host cells to establish an antiviral response; therefore, the strategies that SVCV uses to avoid the cellular IFN response were investigated. Here, we report that the SVCV P protein is phosphorylated by cellular TANK-binding kinase 1 (TBK1), which decreases IFN regulatory factor 3 (IRF3) phosphorylation and suppresses IFN production. First, overexpression of P protein inhibited the IFN promoter activation induced by SVCV and the IFN activity activated by the mitochondrial antiviral signaling protein (MAVS) although TBK1 activity was not blocked by P protein. Second, P protein colocalized and interacted with TBK1. Dominant negative experiments suggested that the TBK1 N-terminal kinase domain interacted with P protein and was essential for P protein and IRF3 phosphorylation. Finally, P protein overexpression reduced the IRF3 phosphorylation activated by TBK1 and reduced host cellular ifn transcription. Collectively, our data demonstrated that the SVCV P protein is a decoy substrate for the host phosphokinase TBK1, preventing IFN production and facilitating SVCV replication. IMPORTANCE TBK1 is a pivotal phosphokinase that activates host IFN production to defend against viral infection; thus, it is a potential target for viruses to negatively regulate IFN response and facilitate viral evasion. We report that the SVCV P protein functions as a decoy substrate for cellular TBK1, leading to the reduction of IRF3 phosphorylation and suppression of IFN expression. These findings reveal a novel immune evasion mechanism of SVCV.

Two novel coordination polymers have been hydrothermally synthesized by reactions of Cu(II), Mn(II) salt with 2-carboxyethyl(phenyl)phosphinic acid (H2L), namely, [Cu(L)(H2O)]n (1) and [Mn(HL)2]n (2). Both compounds were well characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopic, power X-ray diffraction and magnetic studies. Compound 1 crystallizes in a noncentrosymmetric monoclinic Cc space group and presents an inorganic two-dimensional (2D) network, whereas compound 2 adopts a noncentrosymmetric Pca21 space group and exhibits a 2D layer structure. Magnetic studies reveal a dominant ferromagnetic interaction in 1, and weak antiferromagnetic coupling between the Mn(II) ions in 2 mediated by phosphinico group, respectively.

Seven novel coordination polymers based on 2,2′-phosphinico-dibenzoic acid (H3L), namely, {[Zn3L2(H2O)4]·2H2O}n (1), [Zn3L2(4,4′-bipy)2]n (2), [Zn(HL)(2,2′-bipy)(H2O)]n (3), {[Cd9L6(H2O)8]·4H2O}n (4), [Cd8L4(OH)2(OAc)2(4,4′-bipy)]n (5), [Mn3L2(4,4′-bipy)(EtOH)(H2O)2]n (6), and [Mn(HL)(2,2′-bipy)(H2O)]n (7), were synthesized under hydro(solvo)thermal conditions. These compounds crystallize in the triclinic P1 space group for 1, 4, 5, and 6, the monoclinic space group C2/c for 2, and the monoclinic P21/c space group for 3 and 7. The L3– ligand displays versatile binding modes in 1–7. Compound 1 is a one-dimensional (1-D) chain coordination polymer with a three-dimensional (3-D) supramolecular framework. Compound 2 is a 3-D porous metal–organic framework (MOF) with two different 4,4′-bipyridine linkers. Compounds 3 and 7 show 1-D zigzag chain structures. Compound 4 exhibits a sophisticated 3-D MOF constructed from two types of Cd8 clusters and one Cd2 dimer, which is the first example exhibiting the coexist...

Experimental determination of the fatigue limit is expensive considering the time and effort involved. To overcome this drawback, several empirical relations based on monotonic tensile properties and/or hardness have been developed for estimating the fatigue limit. In this study, ten estimation methods are evaluated and compared using the experimental data of 171 steels from literature. The scatter band criterion, standard deviation criterion, and statistical analysis are all used to evaluate and compare the predictability of the considered empirical relations. It is found that the fatigue limit can be well correlated with the Brinell hardness. In the absence of Brinell hardness, the ultimate tensile strength-based direct estimation method may be an alternative to estimate the fatigue limit of steels. It is not recommended to estimate the fatigue limit by using the indirect method on the basis of Basquin’s fatigue properties estimated by the monotonic tensile properties even though the fatigue limit of steel is often determined by the experimental Basquin’s curve at 106 cycles.

A 4s-3d-4f heterometallic compound with the formula: [KNi4GdL4(H2O)8]·14·5H2O (1) was obtained by self-assembly of nickel nitrate and gadolinium nitrate with 2,2′-phosphinico-dibenzoic acid (H3L) under hydrothermal condition. Meanwhile, the molecular structure was confirmed by single-crystal X-ray diffraction analysis, IR and EA. The compound composes of a 3D framework based on Ni4Gd nodes and 2,2′-phosphinico-dibenzoate ligand. Interestingly, the {Ni4Gd} node exhibits a metal tetrahedron with Gd(III) ion locked in it. The pentanuclear {Ni4Gd} tetrahedra are further connected by double carboxylate groups resulting a zig-zag chain along b-axis. Moreover, the neighboring chains are bridged by potassium ions with water molecules to form a 3D framework. Variable-temperature magnetic susceptibility studies indicate that ferromagnetic interactions occur between the Ni(II) and Gd(III) ions.

A novel cerium(III) complex, [Ce(Fcterpy)(NO3)3(H2O)]·DEE (1) (DEE = diethylether), bearing the substituted terpyridine ligand 4′-ferrocenyl-2,2′:6′,2″-terpyridine (Fcterpy) has been synthesized and characterized by the single crystal X-ray diffraction technique. Magnetic measurements revealed that complex 1 exhibits a single-ion magnet-like behaviour in the form of field-induced slow magnetic relaxation.

In the present work, based on the Dugdale criterion, a closed-form theoretical crack tip driving force model of simple expressions was proposed for static and fatigue crack propagation along a linear yield strength gradient (YSG). Qualitative and quantitative analyses of the YSG effect on the crack tip driving force are given. The crack tip driving force depends on the yield strength at the crack tip, the YSG within the plastic zone and the applied load. A positive (or negative) YSG has a shielding (or amplifying) effect on the crack tip driving force. A difference of material-toughening mechanisms between smooth and sharp strength gradient was revealed both theoretically and numerically. In the linear YSG case, when a fatigue crack propagates along the YSG at a constant applied cyclic crack tip stress intensity factor, the cyclic crack tip opening displacement decreases (or increases) when the crack propagates towards a higher (or lower)-strength region; however, the cyclic crack tip stress intensity factor increases, no matter when the crack propagates towards a higher- or lower-strength region. This abnormal phenomenon causes theoretical and experimental challenges for characterizing the smooth strength gradient effect on the crack tip driving force.

Six coordination polymers based on 5-(3-pyridylmethoxy)isophthalic acid (H2L), namely [Zn2L2]n (1), [Zn2L2(1,3-bix)]n (2), [CdL(1,3-bix)]n·2nH2O (3), [CdL(azpy)0.5(H2O)]n (4), [CdL(btx)0.5]n (5), and [CdL(btmb)]n·2nH2O (6) (1,3-bix = 1,3-bis(imidazol-1-ylmethyl)benzene, azpy = 4,4′-azobispyridine, btx = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, btmb = 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl), have been synthesized and characterized by elemental analyses, IR spectra, PXRD, thermogravimetry and X-ray structural analysis. Complex 1 is a 3D coordination polymer, simplified as a 4-nodal (4,4,5,5)-connected topology net with point symbol {43.63}{43.62.8}{44.65.8}{44.64.82}. Complex 2 is a 3D coordination polymer, simplified as a crs-d topology net with point symbol {6;82}{62;83;10}. Complex 3 is a 2D coordination polymer with a 2-nodal (3,5)-connected topology net. Complex 4 exhibits a 2D double-layered network with a 2-nodal (3,4)-connected topology net, assembled by two parallel [CdL]n layers pillared by azpy spacer. Complex 5 is a 3D coordination polymer, simplified as a 2-nodal (3,8)-connected topology net with point symbol {43}2{46.618.84}. Complex 6 shows a 2D double-layered network with a 2-nodal (3,5)-connected topology net, constructed from wave-like [CdL]n network pillared by btmb spacer. 5-(3-Pyridylmethoxy)isophthalate exhibits five types of coordination modes. Anhydrous or dehydrated substances of 1–6 were thermally stable to 300–400 °C. These Zn(II)/Cd(II) complexes emit blue luminescence originating from ligand-centered emission.

The bifunctional salt [Co(terpy)2](TCNQ)3·CH3CN (terpy = 2,2′;6′,2′′-terpyridine, TCNQ = 7,7,8,8-tetracyanoquino-dimethane) exhibits a high room temperature conductivity of 0.13 S cm−1 and an anomaly in conductivity at ∼190 K as evidenced by variable temperature structural, magnetic and conductivity studies. The anomaly in the conductivity at 190 K has been correlated with the temperature dependent structural breathing and Jahn–Teller distortion of the low spin state of the SCO units, as well as the charge fluctuations and supramolecular π-stacking interactions of partially charged TCNQ radicals. The modular synthetic approach leads to an accessible source of partially charged TCNQ radicals for the facile preparation of bifunctional molecular materials with high electrical conductivity.

In-situ Scanning Electron Microscopy (SEM) fatigue experiments were carried out to study short fatigue crack propagation (FCP) behavior of various regions (weld zone, interface region and heat affected zone (HAZ)) in a domestic dissimilar metal welded joint of nuclear power plant. The local microstructural effect on short fatigue crack initiation and propagation behavior was investigated with its influence on both material fatigue and structure fatigue analyzed. Considering material fatigue, in the weld region, crack grows along δ ferrites when propagating parallel to the dendrite, and deflects or branches along δ ferrite, γ austenite dendrite, δ/γ interface and grain boundaries when propagating perpendicular to the dendrite; in safe ends, the crack grows along slip lines and coalesces with secondary cracks; in A508 HAZ, the crack propagates or branches along martensite transgranularly. In terms of structural fatigue, the crack tends to deflect when propagating across the weld/A508 interface or weld/316 L interface with the influence of local microstructure, and the weld/A508 interface region has a resistance to FCP due to its high strength. The fatigue crack propagation rate of each region was compared and analyzed. The fatigue fractography was also characterized under SEM to analyze the crack propagation process. Keywords: In-situ SEM, Short fatigue crack propagation, Dissimilar metal welded joint

Solvothermal reaction of CuCl 2 ·2H 2 O and 2-(4-pyridyl)benzimidazole (PyHBIm) in a acetonitrile-water mixed solvent afforded a mixture of [Cu I 2 Cu II (CN) 2 (PyHBIm) 2 Cl 2 ] n ( 1 ) and [Cu II (PyH 2 BIm) 2 Cl 4 ] ( 2 ). Complex 1 is a mixed-valence 1D ribbon Cu(I,II)-cyanide coordination polymer. One Cu(II) center linearly links two Cu(I) ions via two μ 2 -CN bridges. XPS spectrum and bond valence sum (BVS) analysis have confirmed the mixed-valence characteristics. Cu(II) ion adopts a centrosymmetric square-planar geometry surrounded by two cyanides and two pyridyl groups. Cu(I) ions adopt a trigonal geometry coordinated by cyanide, imidazole group and Cl − anion. The cyanide ligand is in situ generated from the cleavage of acetonitrile solvent, which indicates that acetonitrile is an environmentally friend cyanating agent. The mechanism of acetonitrile in situ cleavage under solvothermal condition is explained. Complex 2 is a centrosymmetric mononuclear Cu(II) compound. Four equivalent Cl − anions lie on the equatorial plane. The protonated PyH 2 BIm + cation as a monodentate ligand coordinates to Cu(II) center via pyridyl terminal.