Binding of several heavy metal ions by polyaspartyl polymers and their application to some Chinese herbal medicines

Water‐insoluble polyaspartyl polymers were synthesized by using water as medium instead of organic medium. Taking Ca²⁺ as a reference, the binding of several heavy‐metal ions, including Pb²⁺, Cd²⁺, Hg²⁺, Cr³⁺, Cu²⁺, and Mn²⁺, by polyaspartyl polymers was studied. The experimental results revealed that polyaspartate is an excellent binding agent for the investigated heavy‐metal ions. These cation ions were bound to polyaspartate polymer by the same mechanism as Pb²⁺, which can be explained by ion exchange model. Since polyaspartate has a protein‐resembling structure that is sensitive to trace heavy metal, it was used to remove some trace heavy‐metal elements in Chinese herbal medicines. It was found that polyaspartate material was an effective agent for the removal of Pb²⁺, Cd²⁺, and Hg²⁺ ions from glycyrrhizin, angelica, and gynostemma pentaphyllum. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Syntheses and biological activities of polymers containing methacryloyl‐2‐oxy‐1,2,3‐propanetricarboxylic acid or 5‐fluorouracil

A series of novel copolymers, poly(methacryloyl‐2‐oxy‐1,2,3‐propanetricarboxylic acid‐co‐exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalic acid) [poly(MTCA‐co‐ETAc)], poly(methacryloyl‐2‐oxy‐1,2,3‐propanetricarboxylic acid‐co‐hydrogenethyl‐exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalate) [poly(MTCA‐co‐HEET)], and poly(methacryloyl‐2‐oxy‐1,2,3‐propanetricarboxylic acid‐co‐α‐ethoxy‐exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthaloyl‐5‐fluorouracil) [poly(MTCA‐co‐EETFU)], were prepared from corresponding monomers by photopolymerizations at 25°C for 48 h. The polymers were identified by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopies. The number‐average molecular weights of the fractionated polymers determined by GPC were in the range from 9400 to 14,900 and polydispersity indices were 1.2–1.4. The in vitro IC₅₀ values of polymers against mouse mammary carcinoma (FM3A), mouse leukemia (P388), and human histiocytic lymphoma (U937) as cancer cell lines and mouse liver cells (AC2F) as a normal cell line were much higher compared to that of 5‐fluorouracil (5‐FU). The in vivo antitumor activities of monomers and polymers against mice bearing sarcoma 180 tumor cell line were better than those of 5‐FU. The inhibition of DNA replication and antiangiogenesis activities of MTCA and copolymers were better compared to those of 5‐FU. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 57–64, 2004     

Synthesis and luminescence properties of new blue‐light‐emitting polyconjugated poly{1,1′‐biphenyl‐4,4′‐diyl‐[1‐(4‐t‐butylphenyl)]vinylene} polymers and copolymers

Three new soluble polyconjugated polymers, all of which emitted blue light in photoluminescence and electroluminescence, were synthesized, and their luminescence properties were studied. The polymers were poly{1,1′‐biphenyl‐4,4′‐diyl‐[1‐(4‐t‐butylphenyl)]vinylene}, poly((9,9‐dioctylfluorene‐2,7‐diyl)‐alt‐{1,4‐phenylene‐[1‐(4‐t‐butylphenyl)vinylene‐1,4‐phenylene]}) [P(DOF‐PVP)], and poly([N‐(2‐ethyl) hexylcarbazole‐3,6‐diyl]‐alt‐{1,4‐phenylene‐[1‐(4‐t‐butylphenyl)]vinylene‐1,4‐phenylene}). The last two polymers had alternating sequences of the two structural units. Among the three polymers, P(DOF‐PVP) performed best in the light‐emitting diode devices of indium–tin oxide/poly(ethylenedioxythiophene) doped with poly(styrene sulfonate) (30 nm)/polymer (150 nm)/Li:Al (100 nm). This might have been correlated with the balance in and magnitude of the mobility of the charge carriers, that is, positive holes and electrons, and also the electronic structure, that is, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels, of the polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 307–317, 2006     

一种融合视觉决策理论预测用户选择的方法

为有效解决在眼动人机交互环境中由于难以判断用户决策而导致的米达斯接触问题, 结合视觉决策理论, 通过融合眼动指标与时间序列来预测用户行为。先记录用户浏览目标页面时的眼动数据及进行选择时的点击数据, 并对数据按时间轴进行采样, 得到注视序列; 然后根据注视序列拟合用户进行决策时的注视似然曲线, 确定相关参数与触发阈值。眼动实验结果表明, 单凭注视阈值预测准确率就可以达到78. 3%, 在人机交互环境中拟合的似然曲线与视觉决策理论耦合。方法的实施无须用户进行额外的配合, 不依赖预设的固定阈值; 相对于设置固定触发阈值, 或要用户进行眨眼、按键等操作的传统方法, 交互过程可更顺畅、自然。     

一种基于信息流脉络网的隐蔽通道搜索方法

针对隐蔽流树搜索方法存在的规模大、分析工作量繁重等问题, 提出一种改进的隐蔽通道搜索方法。该方法采用网结构描述系统中的隐蔽信息流, 提出网中隐蔽通道的判定规则; 依据判定规则在深度优先搜索网中隐蔽通信路径过程中排除合法通道; 结合路径中的操作序列构造隐蔽通道工作场景, 从而发现系统中的隐蔽通道。实例分析和对比表明, 该方法可以弥补隐蔽流树搜索方法的不足。     

Synthesis and physicochemical characterization of amphiphilic block copolymer self‐aggregates formed by poly(ethylene glycol)‐block‐poly(ϵ‐caprolactone)

Diblock copolymers with different poly(ε‐caprolactone) (PCL) block lengths were synthesized by ring‐opening polymerization of ε‐caprolactone in the presence of monomethoxy poly(ethylene glycol) (mPEG‐OH, MW 2000) as initiator. The self‐aggregation behaviors and microscopic characteristics of the diblock copolymer self‐aggregates, prepared by the diafiltration method, were investigated by using ¹H NMR, dynamic light scattering (DLS), and fluorescence spectroscopy. The PEG–PCL block copolymers formed the self‐aggregate in an aqueous environment by intra‐ and/or intermolecular association between hydrophobic PCL chains. The critical aggregation concentrations of the block copolymer self‐aggregate became lower with increasing hydrophobic PCL block length. On the other hand, reverse trends of mean hydrodynamic diameters were measured by DLS owing to the increasing bulkiness of the hydrophobic chains and hydrophobic interaction between the PCL microdomains. The partition equilibrium constants (K_v) of pyrene, measured by fluorescence spectroscopy, revealed that the inner core hydrophobicity of the nanoparticles increased with increasing PCL chain length. The aggregation number of PCL chain per one hydrophobic microdomain, investigated by the fluorescence quenching method using cetylpyridinium chloride as a quencher, revealed that 4–20 block copolymer chains were needed to form a hydrophobic microdomain, depending on PCL block length. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3520–3527, 2006     

Synthesis and characterization of in situ polymerized segmented thermoplastic elastomeric polyurethane/layered silicate clay nanocomposites

Nanocomposites based on thermoplastic elastomeric polyurethane (TPU) and layered silicate clay were prepared by in situ synthesis. The properties of nanocomposites of TPU with unmodified clay were compared with that of organically modified clay. The nanocomposites of the TPU and organomodified clay showed better dispersion and exhibited superior properties. Exfoliation of the clay layers was observed at low organoclay contents, whereas an intercalated morphology was observed at higher clay contents. As one of major purposes of this study, the effect of the silicate layers in the nanocomposites on the order–disorder transition temperature (T_ODT) of the TPU was evaluated from the intensity change of the hydrogen‐bonded and free carbonyl stretching peaks and from the peak position change of the N? H bending peak. The presence of the organoclay increased T_ODT by approximately 10°C, which indicated improved stability in the phase‐separated domain structure. The layered silicate clay caused a tremendous improvement in the stiffness of the TPU; meanwhile, a reduction in the ultimate elongation was observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3048–3055, 2006     

新建本科院校学报的科学定位与发展研究

新建本科院校学报存在定位不够科学、学术性不强、特色不突出和编辑队伍素质参差不齐等问题.进行科学的定位是新建本科院校学报可持续发展的前提.应根据校情和社会环境条件来对学报进行定位.在科学定位基础上,要坚持以作者为本,提高原创水平;以编辑为本,提高编辑质量;以读者为本,发挥社会效益.同时,要创新学报管理机制、选题策划和征稿机制,塑造学报特色,从而实现新建拳科院校学报的科学发展.     

Microstructure and mechanical properties of rapidly solidified Al-Cr alloys

The microstructure and mechanical properties of rapidly solidified Al-Cr alloys were investigated by XRD, TEM and microhardness testing instrument. The results indicate that the matrix of rapidly solidified Al-Cr alloys is α-Al solid solution when the Cr content is lower than 4 wt%. However, when the Cr content is above 4 wt%, the microstructures of rapidly solidified Al-Cr alloys are different along cross section. The microstructure of alloy contacting copper roller consists of α-Al and a few intermetallic compounds. With the increase of distance from copper roller, the matrix consists of α-Al and spherical intermetallic compounds which conglomerate in α-Al matrix. These intermetallic compounds are Al₇Cr, Al₁₁Cr and Al₄Cr. The tensile strength has the maximal value when the Cr content is about 8 wt%. The annealed microstructures show that supersaturated α-Al solid solution dissolved with increasing anneal temperature. The starting temperature of the second phase precipitated from the supersaturated α-Al solid solution desponds on the supersaturation. Meanwhile, the microhardness of rapidly solidified Al-Cr alloy reaches maximal value after annealing at 300 °C. Funded by the Innovation Fund for Outstanding Scholar of Henan Province (No. 0621000700)     

Effects of annealing temperature on the microstructure and properties of the 25Mn-3Si-3Al TWIP steel

Microstructures and mechanical properties of the 25Mn twinning induced plasticity (TWIP) steel at different annealing temperatures were investigated. The results indicated that when the annealing temperature was 1000°C,the 25Mn steel showed ex-cellent comprehensive mechanical properties,the tensile strength was about 640 MPa,the yield strength was higher than 255 MPa,and the elongation was above 82%. The microstructure was analyzed by optical microscopy (OM),X-ray diffraction (XRD),and transmission electron...