Synthesis of bipolar tetradentate ligand and determination of fructose 1,6-diphosphate by resonance light scattering of its supramolecular polymer

In this paper, a novel method was established for determination of fructose 1,6-diphosphate (F-1,6-BP) based on resonance light scattering (RLS), and a type of bipolar tetradentate schiff base H₄L was synthesized. The study showed that under the optimization condition with the ligand concentration of 5 nmol mL⁻¹, pH 6.5, the reaction temperature of 25 °C, the reaction time of 30 min, RLS intensity had good linearity with the concentration of F-1,6-BP within the range of 0.4–5.0 nmol mL⁻¹, the limit of detection was 0.16 nmol mL⁻¹ and the relative standard deviation (RSD) was 1.83%. In vitro feasibility study, four groups of medical injections and two groups of human urine were analyzed, the RSD of six parallel experiments was approximately 2%, and the recovery value changed from 98.0 to 102.5%. As shown herein, this method has high sensitivity, good precision and recovery.

     

D-D 中子发生器n-γ 密度测井的蒙特卡罗模拟研究

根据D-D 反应中子的能谱和角分布数据,建立了中子源模型;根据石灰岩地层标准刻度井群数据,建立了井模型。采用MCNP 程序模拟了井中中子和γ 射线的输运,得到了不同地层密度和不同源距处NaI 探测器中的混合γ 射线能谱和非弹γ 射线能谱。在混合γ 射线能谱2.5~5.0 MeV 能区开窗,研究了开窗区混合γ 射线相对计数随源距的变化关系,确定源距应选择在30~80 cm 范围,给出了密度与混合γ 射线计数之间的非线性关系。研究表明,可以利用D-D中子源的混合γ 射线能谱来实现n-γ 密度测井。A D-D neutron source model was developed according to the neutron spectrum and the neutron angular distribution of D-D reaction. A standard calibration well model was built. The transports of the D-D neutrons and γ-rays in the well were simulated using MCNP code. The mixed γ-spectra and inelastic γ-spectra in the NaI detector were obtained for both different distances from a neutron source and different densities. Mixed γ count in the energy range of 2.5 to 5.0 MeV as a function of distance shows that the NaI detector should be located at a distance of 3080 cm from the neutron source. The nonlinear relationships between the density and the mixed γ count were presented in this paper.It was demonstrated that the energy spectrum of mixed γ rays can realize the n-γ density logging.     

Incomplete decision contexts: Approximate concept construction,rule acquisition and knowledge reduction

Incomplete decision contexts are a kind of decision formal contexts in which information about the relationship between some objects and attributes is not available or is lost. Knowledge discovery in incomplete decision contexts is of interest because such databases are frequently encountered in the real world. This paper mainly focuses on the issues of approximate concept construction, rule acquisition and knowledge reduction in incomplete decision contexts. We propose a novel method for building the approximate concept lattice of an incomplete context. Then, we present the notion of an approximate decision rule and an approach for extracting non-redundant approximate decision rules from an incomplete decision context. Furthermore, in order to make the rule acquisition easier and the extracted approximate decision rules more compact, a knowledge reduction framework with a reduction procedure for incomplete decision contexts is formulated by constructing a discernibility matrix and its associated Boolean function. Finally, some numerical experiments are conducted to assess the efficiency of the proposed method.     

Synthesis and antineoplastic activity of novel water-soluble curcumol derivatives

6-Succinyl curcumol sodium salt was synthesized by reaction of curcumol with succinic acid. The structure of the derivative was confirmed by NMR spectroscopy and mass spectrometry. Furthermore, the derivative showed antitumor activity, which makes it a promising antitumor drug candidate that overcomes the insolubility in water.     

REGULARITY OF P-HARMONIC MAPPINGS INTO NPC SPACES

Let M be a C²-smooth Riemannian manifold with boundary and X be a metric space with non-positive curvature in the sense of Alexandrov.Let u:M→X be a Sobolev mapping in the sense of Korevaar and Schoen.In this short note,we introduce a notion of p-energy for u which is slightly different from the original definition of Korevaar and Schoen.We show that each minimizing p-harmonic mapping(p≥2)associated to our notion of p-energy is locally Holder continuous whenever its image lies in a compact subset of X.     

Tris(benzimidazolyl)amine-Cu(II) coordination units bridged by carboxylates: structures and DNA-condensing property

Multinuclear multibenzimidazole metal complexes frequently exhibit novel structures and properties, and are an example of versatile compounds in bioinorganic chemistry. In this work, first, we synthesized the mononuclear complex [Cu(ntb)(H(2)O)](2+), 1, by using tris[(benzimidazol-2-yl)methyl]amine (ntb). Then, a library of multicationic ntb-Cu(II) complexes, 2-9, was prepared by replacing the labile water molecule in 1 with multifunctional carboxylates acting as a bridge linker between two or four ntb-Cu(II) units under slightly acidic or alkaline conditions. Their X-ray crystal structures reveal that these complexes contain one, two or four [Cu(ntb)](2+) units. The pH media used in preparation can control the coordination patterns of the carboxylates and the overall architecture of the complexes, although the Cu(II) centers in the complexes always maintain a five-coordinated structure regardless of the preparation conditions used. Both intra- and inter-molecular π···π interactions involved in the benzimidazoles, as well as extensive hydrogen bonding networks in the complexes were observed to occur in the crystal packing. We selected complexes 1 and the dicarboxylate-bridged 4-7 as potential DNA condensers, as they can be dissolved to the required levels for examining their DNA-binding and -condensing properties in the buffer solutions tested (pH 7.4). For these complexes, the effects of the structural variations, including the number of Cu(II) ions and positive charges, length of linkers, and overall architecture, on the DNA-binding and -condensing properties and cytotoxicity were assessed and compared by biophysical measurements. The results from absorption titration showed that the affinities of the complexes for DNA are dominated by both the electrostatic interaction between them and the π···π interactions through the intercalation of the benzimidazolyl groups in the complexes into DNA base pairs. The DNA-condensing ability was observed to be mainly controlled by the numbers of positive charges on the complexes, and less correlated with the carboxylate linkers. Moreover, no direct relationships have been found between the apparent DNA-binding affinity and DNA-condensing ability of the complexes. The ability of DNA condensation triggered by 7b that carries four ntb-Cu(II) units and six positive charges is much stronger than those by the other complexes, but it also exhibits the largest cytotoxicity. This work aids in understanding the structure-activity relationships for metal complexes likely acting as a new type of gene-delivery systems.     

Thermal Stability,Microstructure and Photocatalytic Activity of the Bismuth Oxybromide Photocatalyst

Flake BiOBr was first prepared by a solution method at room temperature. Then, the produced BiOBr was calcined at different temperatures. It was found that BiOBr is not a stable compound. It transforms to plate‐like Bi₂₄O₃₁Br₁₁at around 750°C and the formed Bi₂₄O₃₁Br₁₁ can further convert to rod‐like α‐Bi₂O₃ at around 850°C. The prepared compounds were characterized with X‐ray diffraction (XRD), N₂ physical adsorption, scanning electron microscopy (SEM), and UV‐Vis diffuse reflectance spectra (DRS), respectively. The photocatalytic activity of the produced bismuth oxybromides was evaluated by photocatalytic decomposition of acid orange II under both visible light (λ>420 nm) and UV light (λ=365 nm) irradiation. Results show that these compounds have different band gaps and different photocatalytic properties. The band gap energies of the as‐prepared samples were found to be 2.82, 2.79, 2.60 and 3.15 eV for BiOBr, BiOBr/Bi₂₄O₃₁Br, Bi₂₄O₃₁Br, and α‐Bi₂O₃, respectively. Under both UV light and visible light irradiation, the photocatalytic activity follows the order: BiOBr/Bi₂₄O₃₁Br mixture>BiOBr>Bi₂₄O₃₁Br>α‐Bi₂O₃. The change in photocatalytic activity could be attributed to the different light absorption ability and microstructures of the photocatalysts.     

Biochemical properties of K11,48-branched ubiquitin chains

The affinities of chemically synthetic linkage- and length-defined K_11,48-branched ubiquitin chains binding to ubiquitin receptor S5a were quantitatively measured. Proteasome-associated deubiquitinase Rpn11 showed a higher activity towards K_11,48-branched ubiquitin chains.     

Synthesis and properties of bulk-biodegradable phase change materials based on polyethylene glycol for thermal energy storage

The bulk-biodegradable solid–solid phase change materials (SSPCMs) based on phase change polyethylene glycol (PEG) were synthesized by solvent-free polyaddition. On the basis of the fact that the water absorption is up to 800 mass% and that the poly(ethylene oxide) molecular chains can be degraded by microorganisms, the bulk-biodegradable mechanism of SSPCMs was put forward and studied. The X-ray diffraction patterns and the polarizing optical microscopy images show the SSPCMs possess the defective crystal and small grain compared with PEG. The differential scanning calorimetry data demonstrate the melting temperature and enthalpy of the synthesized SSPCMs are, respectively, 41 °C and 128 J g^?1. The bulk-biodegradable SSPCMs have the preeminent thermal reliability and the high thermal stability due to the onset thermal degradation temperature above 302 °C, which will give a good insight into bulk-biodegradable PCM system.     

Enhancement of bioavailability by formulating rhEPO ionic complex with lysine into PEG–PLA micelle

The electron transport properties of CO adsorbed SiC nanotubes as a function of concentration density and structural deformation have been characterized for the single-walled (7,0) zigzag model using a combined formalism of density-functional theory and nonequilibrium Green’s function. It is found that CO adsorption can significantly suppress the transmission spectrum of SiC nanotube for a wide range of energies. As the concentration increases, a density-dependent superimposed transport gap exists and widens the initial electronic band gap of SiC nanotube. Under the same applied bias voltage, the current through SiC nanotube decreases with the increasing CO concentrations. The local torsional deformation has no effect on this essential motif. However, the current in the locally twisted system is larger than that of the undeformed one. The transmission suppression and the current differences can be attributed to the response of the localized impurity state induced by CO adsorption to density and deformation. Our results show that SiC nanotube can be a promising gas sensor for CO detection.