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Three one-dimensional metal–nitroxide complexes [Cu(NIT4Py)2(1,4-chdc)] n (1), {[Cu(IM4Py)2(1,4-chdc)(H2O)]·H2O} n (2) and {[Zn(IM4Py)2(1,4-chdc)(H2O)2]·H2O} n (3) (NIT4Py = 2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, IM4Py = 2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and 1,4-chdc = 1,4-cyclohexanedicarboxylate anion) have been synthesized and characterized structurally as well as magnetically. All three complexes crystallize in neutral one-dimensional chains in which the nitroxide–metal–nitroxide units are linked by linear 1,4-cyclohexanedicarboxylate anions. The 1,4-chdc ligands only present the e,e-trans-configuration in these complexes, although there are both cis- and trans-isomers in the free ligand. Magnetic measurements show that complexes 1 and 2 both exhibit weak antiferromagnetic interactions between the copper atoms and nitroxide radicals.

Three new MOFs with the same components but different structures and magnetic behavior, {[Cu6(atr)6(H2O)2(µ3-OH)2(SO4)5]·5.25H2O} n (1), {[Cu2(atr)2(µ-OH)2(SO4)]·3H2O} n (2), and {[Cu7(atr)6(H2O)6(µ3-OH)2(SO4)6]·2H2O} n (3) (atr = 4-amino-1,2,4-triazole), were respectively synthesized by diffusion reactions in the presence of different structure-directing agents. Complex 1 is a slightly spin-frustrated antiferromagnetic layer with sulfonate aggregated CuII 6 clusters periodically extended by ditopic sulfonate linkers. 2 is a grid-based coplanar sheet with hydroxyl group bridged -CuOCu- linear-chain interlinked by pairs of µ3-atr ligands, exhibiting strong antiferromagnetic interactions to lead to an S = 0 spin ground state at low temperature. In contrast, air-instable 3 has a ladder-like broad-ribbon structure constructed from triangular CuII 3 cores and centrosymmetric CuII 1 octahedra. Obviously, the variable CuII-ligand connectivity and the involving magnetic properties are significantly dominated by the cooperative and variable binding modes of the mixed sulfonate-atr ligands and bi-/tridentate bridging hydroxyl heterobridges.

A loop-mediated isothermal amplification (LAMP) assay was developed and validated for the specific detection of Salmonella in food. The four primers required for LAMP were designed using a conserved region in the histidine transport protein-coding region of Salmonella. Seventy-nine reference strains of 72 Salmonella serovars and 23 non-Salmonella strains were detected by LAMP. The detection limit of this assay is 16 CFU per reaction in pure culture, up to tenfold more sensitive than that of the PCR assay with the same target gene. When applied in raw food samples, a sample pretreatment protocol was performed that included a pre-enrichment step in 0.1 % buffered peptone water, followed by a selective enrichment in Rappaport–Vassiliadis medium. Using this method, 200 assorted food samples were investigated for Salmonella, including fresh pork, whole chickens, and green vegetables. The sensitivity of LAMP for the detection of Salmonella in food samples was 93.55 %, versus 87.10 % that tested positive using conventional PCR. The results from this study showed that the HisJ-based LAMP is an effective method for the detection of foodborne Salmonella.

Two trypsin isoforms (GT-A and GT-B) from the grass carp (Ctenopharyngodon idellus) intestine were isolated and purified. SDS-PAGE electrophoresis showed that GT-A and GT-B had relative molecular masses of 30,740 and 26,400, respectively. Enzyme activity was inhibited by three organic trypsin inhibitors but not by EDTA. They had optimal pH of 8.0 and 8.5, and optimal temperatures of 38.5 and 44.0 degrees C, respectively, when hydrolyzing N-benzoyl-L: -arginine ethyl ester.HCl (BAEE). They lost 95.8 and 93.7% of their activities, respectively, after heating for 20 min at 65 degrees C. Their thermal denaturation temperatures, respectively, were 66.3 and 67.3 degrees C. GT-A has a K(m) value of 21.2 microM and a V(max) of 2.0 x 10(3) min(-1), and GT-B has a K(m) value of 31.7 microM and a V(max) of 3.3 x 10(3) min(-1). Their physiological efficiencies were 94.3 and 105.3 microM(-1) min(-1), respectively. The Arrhenius activation energies of GT-A and GT-B were 4.16 and 4.38 kcal/mol, respectively. The activities of GT-A and GT-B were not activated by Ca(2+), but their thermostability was improved in the presence of Ca(2+). Enzyme activity was reduced in presence of Zn(2+), Cu(2+), Hg(2+) and Al(3+). Thermal stabilities of GT-A and GT-B were intermediate between Arctic and tropical fish species, and consistent with the wide range of water temperatures to which grass carp are exposed in most provinces of China.