[en] Four new polyoxometalate(POM)–templated metal–organic frameworks based on flexible ligands, namely, [Cu_6(bip)_1_2(PMo"V"I_1_2O_4_0)_2(PMo"VMo"V"I_1_1O_4_0O_2)]·8H_2O(1), [Cu"I_3Cu"I"I_3(bip)_1_2(PMo"V"I_1_2O_4_0)_2(PMo"V_1_2O_3_4)]·8H_2O(2), [Ni_6(bip)_1_2(PMo"V"I_1_2O_4_0)(PMo"V"I_1_1Mo"VO_4_0)_2]Cl·6H_2O(3), [Co"I"I_3Co"I"I"I_2(H_2bib)_2(Hbib)_2(PW_9O_3_4)_2(H_2O)_6]·6H_2O(4) (bip=1,3-bis(imidazolyl)propane, bib=1,4-bis(imidazolyl)butane) have been obtained under hydrothermal condition and characterized by single-crystal X-ray diffraction analyses, elemental analyses, and thermogravimetric (TG) analyses. The studies of single crystal X-ray indicate that compounds 1–3 crystallize in the trigonal space group P-3, and compound 4 crystallizes in the triclinic space group P-1. Compounds 1 and 3 represent 3D frameworks, and POMs as the guest molecules are incorporated into the cages which are composed of the ligands and metals, while compounds 2 and 4 show 3D frameworks by hydrogen bonds. This compounds provide new examples of host–guest compounds based on flexible bis(imidazole) ligands. In addition, the electrochemical property and the catalytic property of compound 1 have also been investigated. - Graphical abstract: Four inorganic–organic hybrid compounds based polyoxometalates (POMs) and flexible ligands, namely, have been obtained under hydrothermal conditions and characterized by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra, and thermogravimetric (TG) analyses. Compounds 1–3 are new examples of host–guest compounds based on flexible bis(imidazole) ligands and POMs as the guest molecules are incorporated into the cages which are composed of the ligands and metals. - Highlights: • Polyoxometalate–templated metal–organic frameworks have been prepared. • POMs as the guest molecules are incorporated into the cages. • The cages are flexibility based on flexible bis(imidazole) ligands

[en] The hydrothermal reaction of transition metals, 1H-imidazole-4,5-dicarboxylic acid (H_3ImDC) and 1,2-bi(pyridin-4-yl)ethene (bpe) affords a series of new complexes, namely, [Mn(HImDC)(bpe)(H_2O)] (1), [M(H_2ImDC)_2(H_2O)_2]·(bpe) (M=Fe(2), Co(3), Zn(4), Cd(6)), [Zn_3(ImDC)_2(bpe)(H_2O)]·3H_2O (5) and [Cd(H_2ImDC)(bpe)] (7), which are characterized by elemental analyses, IR, TG, XRPD and single crystal X-ray diffraction. Complex 1 exhibits a one dimensional (1D) zigzag chain with two types of irregular rings, and the 1D chains are linked to form a three dimensional (3D) supramolecular framework by the hydrogen bonding interactions (O–H∙∙∙O and O–H∙∙∙N). Complexes 2–4 and 6 are isomorphous, and they display the mononuclear structures. In these complexes, the O–H∙∙∙O and O–H∙∙∙N hydrogen bonds play an important role in sustaining the whole 3D supramolecular frameworks. Complex 5 shows a (3,3)-connected 3D framework with (10"3) topology, and the lattice water molecules as guest molecules exist in the 3D framework. Complex 7 is a wave-like two dimensional (2D) structure, in which the adjacent 1D chains point at the opposite directions. Moreover, the fluorescent properties of complexes 1–7 and the magnetic property of 1 have been investigated. The water vapor adsorption for complex 5 has been researched at 298 K. - Graphical abstract: Seven new complexes based on different structural characteristics have been hydrothermally synthesized by the mixed ligands. The fluorescent properties, the magnetic property and the water vapor adsorption have been investigated. - Highlights: • The semi-rigid ligand with C=C bonds and imidazole dicarboxylates with some advantages have been used. • A series of new complexes with different structural characteristics have been discussed in detail. • The fluorescent properties, the magnetic property and the water vapor adsorption have been investigated

[en] Pyruvate Kinase M2 (PKM2) is highly expressed in many solid tumors and associated with metabolism reprogramming and proliferation of tumors. Here, we report that PKM2 can bind to DNA Damage-Binding Protein 2 (DDB2), which is necessary for global nucleotide excision repair of UV induced DNA damage. The binding is promoted by UV irradiation and K433 acetylation of PKM2. Over expression of PKM2 facilitates phosphorylation of DDB2 and impairs DDB2-DDB1 binding. Furthermore, knocking down of PKM2 increases cell survival upon UV irradiation, while over expression of PKM2 reduces cell survival and over expression of DDB2-DDB1 reverts this effect. These results reveal a previously unknown regulation of PKM2 on DDB2 and provide a possible mechanism for UV induced tumorigenesis. - Highlights: • PKM2 interacts with DDB2. • UV irradiation increases PKM2-DDB2 binding via up regulation of PKM2 K433 acetylation. • PKM2 facilitates DDB2 phosphorylation and impairs DDB2-DDB1 binding. • PKM2 reduces cell survival upon UV irradiation.

[en] The electronic structure and optical properties of Fe-F co-doped ZnO are calculated by the first principle under the framework of density function theory with the plane wave super soft pseudopotential method. The supercells of Zn₁₆O₁₆, Zn₁₅Fe₁O₁₆, Zn₁₆O₁₅F₁, Zn₁₅Fe₁O₁₅F₁ are constructed. The band structures and optical properties of ZnO before and after doping are calculated and analyzed. The results show that the co-doped system is easier to form than single-doped system and has higher stability; the covalent property of co-doped systems is weakest which is beneficial to separating the photo-generated hole-electron pairs. The impurity energy series of the co-doped system becomes more denser, and the electrons can easily jump from the low energy level to the high energy level which can improve photocatalytic abilities. The addition of Fe³⁺ results in the Fermi energy level entering the conduction band, producing Mott phase transition and enhancing its conductivity. The main peaks of the dielectric function imaginary part of the doping systems move to the low energy region and the absorption peak in visible light region is obviously increased, showing the co-doped of Fe and F is beneficial to improve the photocatalytic abilities. (authors)

[en] The authors describe an aptamer based assay for the food mycotoxin ochratoxin A (OTA). It is based on the use of exonuclease III (Exo III) which assists in signal amplification, and of single-walled carbon nanohorns (SWCNHs) which act as quenchers of fluorescence. The detection scheme employs a hairpin probe (HP) and a signal probe (SP) labeled with carboxyfluorescein (FAM) at its 5′-end. The fluorescence of intact SPs (best measured at excitation/emission wavelengths of 495/518 nm) is quenched by SWCNHs. The HP contains the OTA-specific aptamer sequence and is partially complementary to the SP. After addition of OTA, the aptamer binds OTA and thus exposes a single-stranded sequence that can hybridize with the SP. Exo III digests the SP to liberate the free fluorophore labels. The damaged SPs no longer are adsorbed by the SWCNHs so that fluorescence is no longer quenched. The method has a detection range that is linear from 10 nM to 1000 nM (with a correlation coefficient of 0.997). The limit of detection (LOD), calculated on the basis of a signal to noise ratio of 3, is 4.2 nM. The procedure was validated by the quantitation of OTA in spiked real samples and were found to be free of interference by the sample matrix. Recoveries ranged from 93.8 to 113.0% in beer and from 92.0 to115.9% in red wine. .

[en] Two new interesting compounds, ethanedial-1,2-bis-(2-(1-amino-2,2-dinitroethenyl))hydrazone (EDNH) and 3-dinitromethyl-1,2,4-triazine (DNTA), were synthesized by the reaction of 1-amino-1-hydrazino-2,2-dinitroethylene (AHDNE) and glyoxal under different acid–base conditions, and reaction processes were discussed. Thermal decomposition behaviors of the two compounds were studied with DSC and TG/DTG methods, and the kinetic equations of decomposition process were obtained. Self-accelerating decomposition temperature and critical temperature of thermal explosion are 193.92 and 209.75 °C for EDNH, and 242.46 and 259.94 °C for DNTA, respectively. Specific heat capacities of the two compounds all present a square relationship with temperature in determined temperature range, and molar heat capacities at 298.15 K are 331.30 and 213.13 J mol⁻¹ K⁻¹, respectively. DNTA and EDNH are relatively insensitive (> 35 and > 25 J), which are much lower than that of AHDNE.

[en] The microstructures and strength of pure Ni ball after high speed collision process were investigated. The elongated and equiaxed nanocrystallines with high angle grain boundaries and random grain orientation were formed near the interface position due to high strain and strain rate. Sufficient intragranular recrystallization occurred due to shock induced storage energy. Sufficient recrystallization in the grain interior facilitated to activate dislocation in the process of subsequent deformation and resulted in ameliorated hardness. Moreover, the high angle grain boundaries could effectively impede the dislocation movement, which also significantly enhanced the strength of Ni ball near the interface.

[en] A novel label-free fluorescence aptasensor used for the detection of ochratoxin A (OTA) is presented in this study. When aggregated on the surface of DNA aptamer, aggregation-induced emission (AIE) fluorescence probe presents turn-on fluorescence property. The method proposed in this article was based on an AIE probe, 4, 4-(1E,1E)-2, 2-(anthracene-9, 10-diyl) bis (ethene-2, 1-diyl) bis (N, N, N-trimethylbenzenaminium iodide) (DSAI). With OTA present, the aptamer will combine with OTA and the conformation of the aptamer will switch to an antiparallel G-quadruplex from the initial random coil, which obstructs its digestion by Exo I. After the solution is added with DSAI, DSAI will aggregate on the surface of the aptamer/OTA complex and produces a strong emission. In the range of 5 to 500 ng · ml⁻¹ OTA concentrations, the fluorescence increases with a linear logarithm relationship. The detection limit is 1.9 ng · ml⁻¹. This method was used to detect OTA in spiked real samples, with recoveries and RSDs in the range of 92.2% to 106.3%, and 2.7% to 5.2%, respectively. (paper)

[en] This study describes an aptamer based assay for the mycotoxin ochratoxin A (OTA). The method is based on the use of an OTA-specific aptamer, exonuclease (Exo) III, SYBR Gold as a fluorescent probe, and a complementary strand that specifically combines with the aptamer. In the presence of OTA, the aptamer and OTA hybridize, thereby resulting in the formation of ssDNA, which is not digested by Exo III. Intense fluorescence is observed after addition of SYBR Gold (best measured at excitation/emission wavelengths of 495/540 nm). Fluorescence increases linearly with the log of the OTA concentration in the range from 8 to 1000 ng·mL⁻¹. The detection limit is 4.7 ng·mL⁻¹. The assay was applied to the determination of OTA in diluted [2%(v/v)] red wine, and recoveries and RSDs ranged between 93.5% and 113.8%, and between 3.2% and 5.7%, respectively. .

[en] Highlights: • Ce/CoOOH showed a great catalytic ability in DBD plasma for CA degradation. • Catalytic sites of CoOOH were studied by experiments and DFT simulations. • The decomposition products of O₃ and H₂O₂ on Ce/CoOOH were revealed. • A possible catalytic mechanism of Ce/CoOOH in DBD plasma was proposed. • The degradation pathway of CA was given. Herein, Ce doped CoOOH was used as the catalyst for caffeic acid (CA) degradation by dielectric barrier discharge (DBD) plasma. The treatment performance and catalytic mechanism were studied by a series of experiments and density functional theory (DFT) simulations. The results show that the doping amounts of Ce significantly influenced the catalytic performance of CoOOH in DBD plasma, and the catalytic effect reached maximum when the molar ratio of Ce to Co was 1:9. CA was 100 % degraded by Ce₁/Co₉OOH/DBD with 10 min treatment, while only 75.6 % of CA was degraded by 10 min DBD treatment. Transformation of O₃ and H₂O₂ to ⋅OH was mainly responsible for the catalytic effect. The content of oxygen vacancies and unsaturated Co (Lewis acid sites) of CoOOH was increased by doping Ce according to the results of experiments and simulations, and the change was conducive to the catalytic reactions. DFT simulations also indicated that DBD generated O₃ and H₂O₂ were decomposed to O atoms, OH groups and free OH by Ce/CoOOH. The presence of reductive species in DBD plasma was confirmed, and ⋅H was a kind of important reactive specie for CA degradation. CA degradation pathway was proposed based on the detected degradation products.