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Abstract: On the basis of triangular-shaped [Mn3O] secondary building units, a novel two-dimensional (2D) manganese(III) complex, [NaMnIII 3O(sao)3(btec)0.5(H2O)3]·1.25H2O (1) (H2sao=salicylaldoxime, H4btec=benzene-1,2,4,5-tetracarboxylate acid), was synthesized and structurally characterized. The structure of 1 consists of 2D coordination polymer based on [Mn3O] units bridged by sodium ions and benzene-1,2,4,5-tetracarboxylate groups. Magnetic data analysis shows that antiferromagnetic couplings exist between the manganese(III) ions in [Mn3O] subunit of complex 1. [Copyright &y& Elsevier]

Abstract: On the basis of triangular-shaped secondary building units, a hexanuclear manganese(III) complex, [MnIII 6O2(sao)6(N3)2(H2O)8]·2.5H2O (1) (H2sao=salicylaldoxime), was synthesized and structurally characterized. The structure of 1 consists of two triangular-shaped [Mn3O] connected with end-to-end (EE) azide group. Magnetic data analysis shows that antiferromagnetic couplings dominated in the complex. [Copyright &y& Elsevier]

The stochastic Eigen model proposed by Feng et al. (2007) (Journal of Theoretical Biology, 246, 28) showed that error threshold is no longer a phase transition point but a crossover region whose width depends on the strength of the random fluctuation in an environment. The underlying cause of this phenomenon has not yet been well examined. In this article, we adopt a single peak Gaussian distributed fitness landscape instead of a constant one to investigate and analyze the change of the error threshold and the statistical property of the quasi-species population. We find a roughly linear relation between the width of the error threshold and the fitness fluctuation strength. For a given quasi-species, the fluctuation of the relative concentration has a minimum with a normal distribution of the relative concentration at the maximum of the averaged relative concentration, it has however a largest value with a bimodal distribution of the relative concentration near the error threshold. The above results deepen our understanding of the quasispecies and error threshold and are heuristic for exploring practicable antiviral strategies. [ABSTRACT FROM AUTHOR]

Highlights: [•] 2D framework constructed from Mn6 units with (4,4)-net. [•] Sodium ions act as connector. [•] 2D complex shows slow magnetic relaxation behavior. [ABSTRACT FROM AUTHOR]

Species evolution is essentially a random process of interaction between biological populations and their environments. As a result, some physical parameters in evolution models are subject to statistical fluctuations. In this work, two important parameters in the Eigen model, the fitness and mutation rate, are treated as Gaussian distributed random variables simultaneously to examine the property of the error threshold. Numerical simulation results show that the error threshold in the fully random model appears as a crossover region instead of a phase transition point, and as the fluctuation strength increases the crossover region becomes smoother and smoother. Furthermore, it is shown that the randomization of the mutation rate plays a dominant role in changing the error threshold in the fully random model, which is consistent with the existing experimental data. The implication of the threshold change due to the randomization for antiviral strategies is discussed. [ABSTRACT FROM AUTHOR]