Direct electrochemistry and electrocatalysis of hemoglobin in a multilayer {nanogold/PDDA}n inorganic–organic hybrid film

A new amperometric biosensor for hydrogen peroxide (H₂O₂) has been developed that is based on direct electrochemistry and electrocatalysis of hemoglobin (Hb) in a multilayer inorganic–organic hybrid film. o-Phenylenediamine (PDA) was electropolymerized onto a glassy carbon electrode (GCE), and then negatively charged nanogold particles and positively charged poly(diallyldimethylammonium chloride) (PDDA) were alternately assembled on the PDA/GCE surface. Finally, Hb was electrostatically adsorbed on the surface of gold nanoparticles. The electrochemical behavior of the resulting biosensor (Hb/{nanogold/PDDA}_n/PDA/GCE) was assessed and optimized. The performance and factors influencing the biosensor were studied in detail. Under optimal conditions, the immobilized Hb displayed good electrocatalytic response to the H₂O₂ reduction ranging from 1.3 μM to 1.4 mM with a detection limit of 0.8 μM (at 3δ). In addition, the biosensor exhibited rapid response, good reproducibility, and long-term stability. Electronic supplementary material to this paper is available in electronic form at Correspondence: Dianyong Tang, Department of Chemistry and Life Science, Leshan Teachers College, Sichuan (Leshan) 614000, P.R. China     

Image contrast enhancement using adjacent-blocks-based modification for local histogram equalization

Infrared images usually have some non-ideal characteristics such as weak target-to-background contrast and strong noise. Because of these characteristics, it is necessary to apply the contrast enhancement algorithm to improve the visual quality of infrared images. Histogram equalization (HE) algorithm is a widely used contrast enhancement algorithm due to its effectiveness and simple implementation. But a drawback of HE algorithm is that the local contrast of an image cannot be equally enhanced. Local histogram equalization algorithms are proved to be the effective techniques for local image contrast enhancement. However, over-enhancement of noise and artifacts can be easily found in the local histogram equalization enhanced images. In this paper, a new contrast enhancement technique based on local histogram equalization algorithm is proposed to overcome the drawbacks mentioned above. The input images are segmented into three kinds of overlapped sub-blocks using the gradients of them. To overcome the over-enhancement effect, the histograms of these sub-blocks are then modified by adjacent sub-blocks. We pay more attention to improve the contrast of detail information while the brightness of the flat region in these sub-blocks is well preserved. It will be shown that the proposed algorithm outperforms other related algorithms by enhancing the local contrast without introducing over-enhancement effects and additional noise.     

Relativistic Calculations for Be-like Iron

Relativistic configuration interaction calculations for the states of 1s^22s^2, 1s^22s3l （l = s,p,d） and 1s^22p31 （l=s,p,d） configurations of iron are carried out using relativistic configuration interaction （RCI） and multi-configuration Dirac-Fock （MCDF） method in the active interaction approach. In the present calculation, a large-scale configuration expansion was used in describing the target states. These results are extensively compared with other available calculative and experimental and observed values, the corresponding present results are in good agreement with experimental and observed values, and some differences are found with other available calculative values. Because more relativistic effects are considered than before, the present results should be more accurate and reliable.     

多羟乙基双核大环多胺La(III)配合物对双对硝基苯酚磷酸二酯和DNA 催化水解作用研究

合成了一类新型多羟乙基双核大环多胺La(III)配合物, 其结构经1H NMR, MS, 元素分析等表征. 通过紫外分光光谱法和琼脂糖凝胶电泳技术, 研究了双核大环多胺La(III)配合物催化双对硝基苯酚磷酸二酯的水解反应和对质粒DNA(pUC18)的催化水解作用. 结果表明: 双核大环多胺La(III)配合物可以有效催化双对硝基苯酚磷酸二酯水解和促进质粒DNA在生理条件下的水解裂解. 双对硝基苯酚磷酸二酯的水解速率提高了2.36×104倍. 讨论了配合物结构对水解反应的影响.     

Bond covalency and electronic structure of CaB2O4(III) crystal

The electronic structure of CaB₂O₄(III) crystal obtained by using SIESTA program is reported in this article. It is observed that the band gap values are, respectively, 5.39 and 5.89 eV from our LDA and GGA calculations. The bond covalency and bond valence are calculated with a simplified method. For both Ca–O and B–O types of bond, the bond covalency has a decreasing trend with the increasing bond length. The result of bond covalency in explaining the interaction between atoms has been shown in good agreement with that of Mulliken population analysis. The ionic configuration for CaB₂O₄(III) in the fundamental state is estimated to be Ca^+1.808B^−0.68O^−0.112. A summary of B–O distances for the four phases of CaB₂O₄ crystal from several works is also presented.     

An answer to the Jun-Shim-Lele’s open problem on the fuzzy filters

In this note, a negative answer to the open problem of Jun, Shim and Lele on fuzzy filters of BCI-algebras is given, a necessary and sufficient condition, under which the open problem has a positive answer, is provided. Furthermore, we give two properties of fuzzy filters of BCI-algebras which generalize some results of Jun, Shim and Lele.     

MgSiO3状态方程的分子动力学模拟

利用分子动力学方法,研究了高温高压下钙钛矿结构MgSiO_3的状态方程。研究表明,分子动力学模拟结果精确地再现了广泛温度和压强范围内MgSiO_3的摩尔体积。在300 K压强上升到140 GPa模拟的MgSiO_3状态方程和有效的实验值、他人的拟合值以及基于局域密度近似的第一原理计算结果基本一致。并且更高温度和更高压强下模拟的MgSiO_3状态方程和他人的计算值吻合的很好。另外,还分别计算了300、900、2000和3000 K压强上升到120 GPa时MgSiO_3的体积压缩率。     

相位调制高斯光束在强非局域非线性介质中的传输特性

利用(1+1)维Snyder-Mitchell模型和空间正弦相位调制的方法，讨论了如何控制高斯光束在平面波导中的传输问题，发现只要适当地选择调制参数就可得到稳定对称的三、五和六束子光束的共同传输，其独特全新的相互作用过程在光开关、编码器和分光器上有潜在的应用价值. 关键词： 强非局域非线性介质 空间相位调制 空间光孤子相互作用特性 光开关     

Volterra 积分微分大系统的稳定性

近20年来大系统理论已得到了较大的发展,对其稳定性的研究已引起了人们的足够重视,出版的大量论文与专著中已涉及到微分方程、积分方程、泛函微分方程、随机与抽象微分方程、偏微与复微分方程以及差分方程所定义的大系统.虽然近年来对积分微分方程的研究也引起了不少学者的注意,但很少涉及到此类方程所定义的大系统.本文