桉木APMP制浆过程浆中残余木素分子量的变化

利用凝胶渗透色谱法和元素分析法测定了尾叶桉酶解木素在APMP制浆及漂白过程的分子量变化。研究结果表明：由于HOO-的特殊作用,制浆及漂白之后,浆中剩余木素的平均分子量相对有所增大。     

凝胶色谱净化-毛细管气相色谱法测定渔业水体中乐果

建立凝胶色谱净化-毛细管气相色谱法测定养殖水体中乐果的分析方法。三氯甲烷萃取水样,经凝胶渗透色谱(GPC)净化除去脂类、色素等,采用脉冲不分流进样模式气相色谱法分析,外标法定量。方法检测限为0.022μg/L;加标水平为1.00μg/L时,实际样品回收率为82.5%～97.1%。该方法自动化程度高、净化效果好、重现性好、准确灵敏。实际样品检测结果表明,此方法满足复杂水体中乐果残留检测要求。     

聚酯分子量分布对可纺性的影响

根据不同聚酯切片在常规指标相同的情况下可纺性往往不同，重点介绍用凝胶渗透色谱法和筛析色谱法对聚酯的低分子成分及分子量分布的检测研究，以及分子量分布对可纺性具有的重要意义。     

GPC1 Regulated by miR-96-5p,Rather than miR-182-5p,in Inhibition of Pancreatic Carcinoma Cell Proliferation

To determine the relationships between miR-96-5p/-182-5p and GPC1 in pancreatic cancer (PC), we conducted the population and in vitro studies. We followed 38 pancreatic cancer patients, measured and compared the expression of miR-96-5p/-182-5p, GPC1, characteristics and patients’ survival time of different miR-96-5p/-182-5p expression levels in PC tissues. In an in vitro study, we investigated the proliferation, cycle and apotosis in cells transfected with mimics/inhibitors of the two miRNAs, and determine their effects on GPC1 by dual-luciferase assay. In the follow-up study, we found that the expressions of miR-96-5p/-182-5p were lower/higher in PC tissues; patients with lower/higher levels of miR-96-5p/-182-5p suffered poorer characteristics and decreased survival time. In the in vitro study, the expressions of miR-96-5p/-182-5p were different in cells. Proliferation of cells transfected with miR-96-5p mimics/inhibitors was lower/higher in Panc-1/BxPC-3; when transfected with miR-182-5p mimics/inhibitors, proliferation of cells were higher/lower in AsPC-1/Panc-1. In a cell cycle study, panc-1 cells transfected with miR-96-5p mimics was arrested at G0/G1; BxPC-3 cells transfected with miR-96-5p inhibitors showed a significantly decrease at G0/G1; AsPC-1 cells transfected with miR-182-5p mimics was arrested at S; Panc-1 cells transfected with miR-182-5p inhibitors showed a decrease at S. MiR-96-5p mimics increased the apoptosis rate in Panc-1 cells, and its inhibitors decreased the apoptosis rate in BxPC-3. Dual luciferase assay revealed that GPC1 was regulated by miR-96-5p, not -182-5p. We found that miR-96-5p/-182-5p as good markers for PC; miR-96-5p, rather than -182-5p, inhibits GPC1 to suppress proliferation of PC cells.     

Synthesis,spectral, thermal,and chelation potentials of polymeric hydrazone based on 2,4‐dihydroxy benzophenone

A chelating polymer, poly(2,4‐dihydroxy benzophenone hydrazone–formaldehyde) [poly(DHBPH–F)], was synthesized by the polycondensation of 2,4‐dihydroxy benzophenone hydrazone with formaldehyde in the presence of oxalic acid as a catalyst. Poly(DHBPH–F) was characterized by Fourier transform infrared and ¹H‐NMR spectral data. The molecular weight of the polymer was determined by gel permeation chromatography. Polychelates were obtained when the dimethylformamide solution of the polymer containing a few drops of ammonia was treated with an aqueous solution of metal ions. Elemental analysis of the polychelates indicated that the metal–ligand ratio was 1 : 2. The IR spectra of the polymer–metal complexes suggested that the metals were coordinated through the oxygen of the phenolic? OH group and the nitrogen of the azomethine group. The electron paramagnetic resonance and magnetic moment data indicated a square planar configuration for Cu(II) chelate and an octahedral structure for Ni(II) chelate. The thermogravimetric analysis, differential scanning calorimetry, and X‐ray diffraction data indicated that the incorporation of the metal ions significantly enhanced the degree of crystallinity. The polymerization initiation, electrical conductivity, and catalytic activity of the polychelates are discussed. Heavy‐metal ions [viz., Cu(II) and Ni(II)] were removed with this formaldehyde resin, and the metal‐ion uptake efficiency at different pH's, the nature and concentration of the electrolyte, and the reusability of the resin were also studied. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and properties of branched polybutylenesuccinate

To obtain long branched polybutylene succinate (PBS), modified PBSs were prepared by introducing a branching agent, trimethylol propane (TMP), to the polycondensation system of succinic acid and 1,4‐butanediol. Molecular parameters such as absolute molecular weight and root‐mean‐square (RMS) radius of the modified PBSs were measured by gel permeation chromatography (GPC) with a multiangle laser light‐scattering (MALLS) detector. The RMS radius of TMP05, PBS prepared by incorporating 0.5 wt % TMP during polycondensation, was the smallest of all PBSs tested at the same molecular weight. The notable shear thinning and much reduced loss tangent for TMP05 qualitatively supported the difference in their molecular structures predicted by GPC. The analytical results indicated that introducing 0.5 wt % TMP produced PBS with chain branches long enough to produce molecular entanglements. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1388–1394, 2001     

Orthogonal ligation to spherical polymeric microparticles: Modular approaches for surface tailoring

Modular ligation strategies for the functionalization of polymeric microspheres provide new perspectives for their applications in material science. In the current trend article we highlight variable synthetic procedures for generating functional microspheres via orthogonal modular conjugation chemistries. An overview of the different surface chemistries available is provided, followed by surface-sensitive characterization techniques relevant for the microparticles. Finally, we explore future trends in modular orthogonal modification approaches on microparticles and provide an outlook on the perspectives that the field of surface-modification of polymeric microparticles holds.     

NEURAL NETWORK PREDICTION OF CETANE NUMBERS FOR ISOPARAFFINS AND DIESEL FUEL

A backpropagation neural network was used to correlate and predict the cetane numbers of isoparaffins and diesel fuels. For the isoparaffins, the correlation was made between the chemical structure of the branched paraffins and their cetane number. Thirteen branched paraffins were employed to train the network. The group additivity method was used to express the degree of branching of the isoparaffins. According to their positions in the molecule structure, three carbon groups (methylene [-CH₂-] subdivided into methylene α, β and γ, or further, to a carbon that is not a methylene, methyne [>CH-] and quaternary carbon [>C<]) were regrouped into four categories, and included along with normal boiling points, as the network inputs. For the selected diesel fuels, different combinations of physical properties such as density, viscosity, aniline point, and distillation temperatures were tested as the neural network input. The best model was obtained using density, viscosity, aniline point and ASTM D86 measured distillation temperatures (IBP, 10%, 50%, 90% and FBP) as inputs. The trained network models, when applied to predict the cetane number of other isoparaffins and diesel fuel, were quite accurate.     

GPC的浓度效应

本实验用东洋曹达 HLC-802A GPC 仪考察了几种窄分布聚苯乙烯样品和两种宽分布聚苯乙烯样品.结果表明:(1)在0.10～0.15g/100ml 浓度以下几乎没有浓度效应.(2)浓度再增加,淋洗体积随之增加。(3)分子量随浓度增加而降低,且峰加宽.(4)分子量大者,浓度效应显著.窄分布样品比宽分布样品明显.(5)流速大,浓度效应显著.