Preparation of 2-pyridone-containing tricyclic alkaloid derivatives as potential inhibitors of tumor cell proliferation by regioselective intramolecular N- and C-acylation of 2-pyridone

A novel and practical preparation of 2-pyridone-containing tricyclic alkaloid derivatives was developed. By regioselective intramolecular N- and C-acylation of 2-(4-aryl-2-pyridon-6-yl)benzoic acid, a pair of structural isomers 2-aryl pyrido[2,1-a]isoindole-4,6-diones and 4-aryl 1-methyl-1H-indeno[1,2-b]-pyridine-2,5-diones, as potential inhibitors of tumor cell proliferation, were prepared respectively.     

Study on dispersion stability of copper phthalocyanine (CuPc) blue pigment in water improved by plasma treatments

Oxygen plasma was used to modify the copper phthalocyanine (CuPc) blue pigment. It is effective in improving stability of CuPc pigment in aqueous dispersion. Treatment conditions, e.g., treating time, gas pressure and discharge power, had great influence on the surface properties of pigments. X-ray photoelectron spectroscopy (XPS) indicated that the CuPc blue pigment surface was partially oxidized and polar groups including COH, COOH, C?O were incorporated. Dispersion stability of pigment in water was greatly increased. The plasma modified CuPc blue pigment was applied to on cotton fabric. Rubbing fastness and K/S value of the pigment prints were enhanced.     

Evolution of planetary boundary layer under different weather conditions,and its impact on aerosol concentrations

A field experiment was conducted in Tianjin,China from September 9-30,2010,focused on the evolution of Planetary Boundary Layer（PBL） and its impact on surface air pollutants.The experiment used three remote sensing instruments,wind profile radar（WPR）,microwave radiometer（MWR） and micro-pulse lidar（MPL）,to detect the vertical profiles of winds,temperature,and aerosol backscattering coefficient and to measure the vertical profiles of surface pollutants（aerosol,CO,SO₂,NO_x）,and also collected sonic anemometers data from a 255-m meteorological tower.Based on these measurements,the evolution of the PBL was estimated.The averaged PBL height was about 1000-1300 m during noon/afternoon-time, and 200-300 m during night-time.The PBL height and the aerosol concentrations were anti-correlated during clear and haze conditions.The averaged maximum PBL heights were 1.08 and 1.70 km while the averaged aerosol concentrations were 52 and 17μg/m³ under haze and clear sky conditions,respectively. The influence of aerosols and clouds on solar radiation was observed based on sonic anemometers data collected from the 255-m meteorological tower.The heat flux was found significantly decreased by haze （heavy pollution） or cloud,which tended to depress the development of PBL,while the repressed structure of PBL further weakened the diffusion of pollutants,leading to heavy pollution.This possible positive feedback cycle（more aerosols→lower PBL height→more aerosols） would induce an acceleration process for heavy ground pollution in megacities.     

基于紧凑拉伸剪切结构的复合型疲劳裂纹扩展研究

针对含I-II型复合裂纹的紧凑拉伸剪切(CTS)试样,研究了不同加载角度下的裂纹扩展路径及裂纹扩展寿命,通过实验数据给出了适宜于CTS试样的等效应力强度因子关系式,并基于此提出了一种新的I-II型复合裂纹扩展模型。研究表明,CTS试样的裂纹沿与加载方向近垂直的方向扩展,基于Tanaka公式的等效应力强度因子更适合于本文CTS试件的裂纹扩展寿命评估。当加载角度处于0°~45°之间时,提出的复合型裂纹扩展模型预测误差控制在5.49%之内,验证了分析模型的可行性和准确性。     

平面叶栅跨音流场气动特性的数值研究

通过对模型方程的分析，给出了一种新的隐格式构造思想。将它运用到关通量分裂格式中，可得到无近似因子分解、无矩阵运算的高效二阶精度隐式矢通量分裂差分格式，并用来直接求解时间平均Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程组。数值计算标明：该方法具有精度高、稳定性好、计算量少、收敛快等优点，在平面叶栅跨音流场的计算中，较好地捕获了激波，与实验比较，结果令人满意。     

Effect of magnetic field on the TC and magnetic properties for the aligned MnBi compound

In the compound MnBi, a first-order transition from the paramagnetic to the ferromagnetic state can be triggered by an applied magnetic field and the Curie temperature increases nearly linearly with an increase in magnetic field by ∼2 K/T. Under a field of 10 T, T_C increases by 20 and 22 K during heating and cooling, respectively. Under certain conditions a reversible magnetic field or temperature induced transition between the paramagnetic and ferromagnetic states can occur. A magnetic and crystallographic H-T phase diagram for MnBi is given. Magnetic properties of MnBi compound aligned in a Bi matrix have been investigated. In the low temperature phase MnBi, a spin-reorientation takes place during which the magnetic moments rotate from being parallel to the c-axis towards the basal plane at ∼90 K. A measuring Dc magnetic field applied parallel to the c-axis of MnBi suppresses partly the spin-reorientation transition. Interestingly, the fabricated magnetic field increases the temperature of spin-reorientation transition T_s and the change in magnetization for MnBi. For the sample solidified under 0.5 T, the change in magnetization is ∼70% and T_s is ∼91 K.     

Reversibly self-assembled pH-responsive PEG-p(CL-g-TMC) polymersomes

Polymersomes have gained much interest within the biomedical field as drug delivery systems due to their ability to transport and protect cargo from the harsh environment inside the body. For an improved drug efficacy, control over cargo release is however also an important factor to take into account. An often employed method is to incorporate pH sensitive groups in the vesicle membrane, which induce disassembly and content release when the particles have reached a target site in the body with the appropriate pH, such as the acidic microenvironment of tumor tissue or the endosome. In this paper, biodegradable poly(ethylene glycol)-poly(caprolactone-gradient-trimethylene carbonate)-based polymeric vesicles have been developed with disassembly features at mild acidic conditions. Modifying the polymer backbone with imidazole moieties results in vesicle disassembly upon protonation due to the lowered pH. Furthermore, upon increasing the pH efficient re-assembly into vesicles is observed due to the switchable amphiphilic nature of the polymer. When this re-assembly process is conducted in presence of cargo, enhanced encapsulation is achieved. Furthermore, the potency of the polymeric system for future biomedical applications such as adjuvant delivery is demonstrated.     

Metrological role of neutron activation analysis. IA. Inherent characteristics of relative INAA as a primary ratio method of measurement

In a series of three papers, the inherent characteristics of relative instrumental neutron activation analysis (INAA) as a primary ratio method of measurement, the unique functions of parametric INAA as an ideal back-up method of the relative INAA, and the valuable role of INAA in characterization of sampling behavior of individual elements in certified reference materials (CRMs) will be discussed. In this paper, the first of the series, the uncertainty evaluation and the traceability of values measured by neutron activation analysis (NAA), especially instrumental NAA (INAA), will be described to demonstrate the method at its ”the state-of-the-art” level can meet CCQM criteria for a primary ratio method. The scope and examples will be given. Received: 19 March 2001 Accepted: 2 October 2001     

The fluorescence of polyamidoamine dendrimers peripherally modified with 1,8-naphthalimide groups: Effect of the rare earth ions and protons

We report the absorption spectra, fluorescent spectra and photophysical properties of G 2.0 polyamidoamine dendrimers with peripheral 1,8-naphthalimide groups with the hydrogen ions, the rare earth ions (Er³⁺, Tb³⁺, Nb³⁺, Eu³⁺, Yb³⁺ and Gd³⁺) and the mixture of the rare earth metal and hydrogen ions. The presence of the rare earth ions and hydrogen ions was found to enhance the fluorescence owing to the coordination between the rare earth metal or hydrogen ions and internal amido groups of polyamidoamine (PAMAM) from dendrimer. The result from the 3D isogram of the fluorescence spectra for the dendrimers with peripheral 1,8-naphthalimide groups show that it was obtained for the different emission fluorescence intensity and scope by varying the excitation wavelength and the different rare earth ions as well as its concentration. The results obtained reveal that the capacities of these systems might have acted as a sensitive label agent of the rare earth cations and protons.     

Ab Initio Calculation of Room Temperature Ionic Liquid 1-Ethyl-3-Methyl-Imidazolium Chlorocuprate (Ⅰ)

The Hartree-Fock method has been employed to investigate the electronic structures of EMIM (1-ethyl-3-methyl-imidazolium ), CuCl2-, Cu2Cl3-, CuCl32-, EMIM -CuCl2-, EMIM -Cu2Cl3-,and EMIM -CuCl32- pairs. Full optimization and frequency analyses of EMIM , CuCl2-, Cu2Cl3-, CuCl32-,eight initial EMIM -CuCl2-, six EMIM -Cu2Cl3-, and four EMIM -CuCl32- geometries have been carried out using Gaussian-94 soft-package at 6-31 G(d,p) basis set level for hydrogen, carbon, nitrogen, chlorine atoms and Hay-Wadt effective core potential for copper atom. The electronic structures of lowest energy of EMIM -CuCl2-, EMIM -Cu2Cl3-, EMIM -CuCl32-, single EMIM , CuCl2-, Cu2Cl3-, and CuCl32- have been comparatively studied. The calculated results showed that EMIM -CuCl2- pair conformer of lowest energy was five ring parallel to Cl-Cu-Cl with 3.2 (A) distance, EMIM -CuCl32- pair conformer of lowest energy was five ring parallel to CuCl32-plane with 3.4 (A) distance, and the optimized EMIM -Cu2Cl3- pair conformer of lowest energy was five ring perpendicular to Cl-Cu-Cl-Cu-Cl plane with 3.0 (A) distance between the terminal Cl atoms and the 5-ring of EMIM . The cohesion between cations and anions analyses suggested that all stationary points are minimum because of no appearing of imaginary frequency.The assigned frequencies were in agreement with the experimental report. The low energy of interaction because of the bulky asymmetry of EMIM and the charge dispersion of cation and anion leads to the low melting point of the ionic liquids, EMIM -CuCl2-, EMIM -Cu2Cl3-, and EMIM -CuCl32-. The interaction energy of EMIM -CuCl2-, EMIM -Cu2Cl3-, and EMIM -CuCl32- is 309.0 k J/mol, 316.8 k J/mol, and 320.2 k J/mol, respectively. The relationship of interaction energy via distance between cations and anions was also investigated by single point energy scan.