Preparation of semirigid polyurethane foam with liquefied bamboo residues

Bamboo residues were liquefied by using a solvent mixture consisting of polyethylene glycol 400 and crude glycerol (4/1, w/w) with 98% sulfuric acid as catalyst at 160°C for 120 min. The liquefied bamboo had hydroxyl values from 178 to 200 mg KOH/g and viscosities from 507 to 2201 mPa S. The obtained bamboo‐based polyols were reacted with various amounts of polyaryl polymethylene isocyanate (PAPI), using distilled water as blowing agent, silicone as surfactant, and triethylenediamine and dibutyltine dilaurate as cocatalyst to produce semirigid polyurethane (PU) foams. The [NCO]/[OH] ratio was found to be an important factor to control the mechanical properties of PU foams. At a fixed [NCO]/[OH] ratio, both density and compressive strength of PU foams decreased with the increase of bamboo content. The microstructure of PU foams indicates that [NCO]/[OH] ratios are important for cell formation and chemical reactions. The uniformity and cell structure of the foams are comparable to their corresponding compressive strengths. Moreover, the thermogravimetry analysis showed that all the semirigid PU foams had approximately the same degradation temperature of about 250 to 440°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

新型高效捕收剂EM-2及其在包头矿石浮选中的应用

研制合成了一种含芳基、羧基及磺酸基团的新型浮选药剂EM—2。该药剂与氧化石腊皂混合(称之为SLM)作捕收剂,水玻璃作调整剂,用于包头白云鄂博红铁矿反浮选萤石中,工业分流试验在原矿铁品位35.11%时,获得铁精矿品位61.10%,回收率80.31%,精矿含氟0.74%,含磷0.14%的良好技术指标。工业应用获得的生产指标为:原矿铁品位31.32%,精矿铁品位60.38%,回收率为73.43%,精矿含氟0.58%,含磷0.124%。     

曲率驱动的基于亥姆霍兹涡量方程的图像修复模型

图像修复模型根据已知区域信息自动修复目标区域,且保证修复后的图像满足人眼视觉系统的要求,目标区域轮廓自然.理论分析证明,流体力学中无粘亥姆霍兹涡量方程可以实现图像修复.根据曲线和曲面运动方程,使用曲率驱动亥姆霍兹修复模型中的等照度线传输方向.曲率是图像几何特征作用的结果,所以新模型可以很好地保持图像中的线性特征.图像中涡量为平滑程度的度量,二维图像域中涡量具有扩散性,对涡量方程的结果做各向异性扩散,使等照度线间的图像信息交互.亥姆霍兹涡量方程修复模型中的各个参数及扩散过程是涡量扩散性和耗散性以及图像几何特征作用的结果,扩散后的修复模型稳定且不存在错误的传输方向.理论和实验证明了曲率驱动的亥姆霍兹涡量方程模型在图像修复中的有效性.     

Doxycycline Decreases Atherosclerotic Lesions in the Aorta of ApoE-⁄- and Ovariectomized Mice with Correlation to Reduced MMP-2 Activity

Atherogenic events promote changes in vessel walls, with alteration of the redox state, and increased activity of matrix metalloproteinases (MMPs). Thus, this study aims to evaluate aortic remodeling, MMP activity, and reactive oxygen species (ROS) levels after treatment with doxycycline in ApoE^-⁄- and ovariectomized mice (OVX). Female ApoE^-⁄--knockout mice (5 weeks) were submitted to ovariectomy surgery to induce experimental menopause. They then received chow enriched with 1% cholesterol to induce hypercholesterolemia. The animals were divided into two experimental groups: ApoE^-⁄-/OVX vehicle and ApoE^-⁄-/OVX doxycycline (30 mg/kg) administered by gavage once a day for 28 days (15th to the 18th week of life). Blood samples were collected to measure total cholesterol and fractions. The aorta was used for morphometry and to measure the activity and expression of MMP-2 and ROS levels. The ApoE^-⁄-/OVX doxycycline group showed no change in total and fraction cholesterol levels. However, there was a reduction in ROS levels, MMP-2 expression, and activity that correlated with a decrease in atherosclerotic lesions relative to the ApoE^-⁄-/OVX vehicle (p > 0.05). Therefore, we conclude that doxycycline in ApoE^-⁄-/OVX animals promotes a reduction in atherosclerotic lesions by reducing ROS and MMP-2 activity and expression.     

螺旋藻(Spirulina Platensis)多糖蛋白对辐射诱发小鼠PCE微核率及白细胞数的影响

本试验通过对NIH小鼠骨髓细胞微核分析及外周血白细胞计数表明,螺旋藻多糖蛋白能显著减轻辐射对小鼠PCE微核率及白细胞数的影响。故螺旋藻多糖蛋白有可能作为一种新的有效的天然辐射防护剂。     

A Multifunctional Pro‐Healing Zwitterionic Hydrogel for Simultaneous Optical Monitoring of pH and Glucose in Diabetic Wound Treatment

Diabetic ulcer is the most common kind of chronic wound worldwide. Though great efforts have been devoted, diabetic ulcer still remains as a challenge that requires constant monitoring and management. In this work, a multifunctional zwitterionic hydrogel is developed to simultaneously detect two fluctuant wound parameters, pH and glucose level, to monitor the diabetic wound status. A pH indicator dye (phenol red) and two glucose sensing enzymes, glucose oxidase (GOx) and horseradish peroxidase (HRP), are encapsulated in the anti‐biofouling and biocompatible zwitterionic poly‐carboxybetaine (PCB) hydrogel matrix. The visible images are collected by a smartphone and transformed into RGB signals to quantify the wound parameters. Results show that the activity and stability of both two enzymes are improved within PCB hydrogel, and the K_cat/K_m value of PCB‐HRP is ≈5.5 fold of free HRP in artificial wound exudate. This novel wound dressing can successfully monitor the pH range of 4–8 and glucose level of 0.1–10 × 10^?3 m . Meanwhile, it also provides a moist healing environment that can promote diabetic wound healing. This multifunctional wound dressing may open vistas in chronic wound management and guide the diabetes treatment in clinical applications.     

Establishment of the Comprehensive Evaluation System of Cold Stamping Die Quality

A comprehensive evaluation system of die quality, a multiplayer hierarchical amendment index system according to the characteristics of cold stamping die production, an evaluation standard referring to the technique and design rules of dies, and a scientific evaluation by using the multiplayer hierarchical and the fuzzy comprehensive evaluation methods are presented in this paper. The applications show that the system can be used to evaluate the die quality objectively, fairly, and reasonably. Translated from Journal of South China University of Technology (Natural Science Edition), 2004, 32(3)     

氨氮废水生化预处理技术

工业废水如化肥、焦化、炼化酸洗等高氨氮废水的处理一直是难点,经吹脱、汽提或其他方法处理后.出水氨氮含量仍然较高(200～500mg/L),无法直接采用生物法处理.作者试验研究了化学沉淀、化学氧化及离子交换等方法对300mg/L的氨氮废水的处理效果,从技术及经济方面筛选出了最佳的生化预处理工艺,并得出结论:采用改性沸石与MAP法联用为最佳的预处理工艺,不仅具有良好的处理效果同时也拥有较低的经济成本.