Permeation of a fully ionized species across a polarized supported liquid membrane

An analytical technique for the detection of permeation of a fully ionized analyte across a lipophilic membrane is reported. The system, which is comprised of two aqueous compartments (donor and acceptor) separated by a supported liquid membrane, is based on the parallel artificial membrane permeation assay (PAMPA), widely used in the drug discovery process to estimate permeability in vivo. The in situ spectroelectrochemical method developed here employs mechanical stirring of the solution phases on either side of the membrane, external polarization of the membrane, and in situ detection of the analyte via UV-vis spectrophotometry. The flux of the crystal violet cation across the membrane is simultaneously measured via UV-vis spectrophotometry and voltammetry/chronoamperometry as a function of applied potential. The relative contribution of two permeation modes, i.e., that due to naked ions and ion-pairs, is thereby quantified. The open circuit potential difference between the two aqueous compartments and the cyclic voltammetric response are also recorded as a function of time and compared with the predicted values.     

Vitamin D content and variability in fluid milks from a US Department of Agriculture nationwide sampling to update values in the National Nutrient Database for Standard Reference

This study determined the vitamin D₃ content and variability of retail milk in the United States having a declared fortification level of 400 IU (10 μg) per quart (qt; 1 qt = 946.4 mL), which is 25% daily value per 8 fluid ounce (236.6 mL) serving. In 2007, vitamin D₃ fortified milk (skim, 1%, 2%, whole, and 1% fat chocolate milk) was collected from 24 statistically selected supermarkets in the United States. Additionally, 2% milk samples from an earlier 2001 USDA nationwide collection were reanalyzed. Vitamin D₃ was determined using a specifically validated method involving HPLC with UV spectroscopic detection and vitamin D₂ as an internal standard. Quality control materials were analyzed with the samples. Of the 120 milk samples procured in 2007, 49% had vitamin D₃ within 100 to 125% of 400 IU (10 μg)/qt (label value), 28% had 501 to 600 IU (12.5-15 μg)/qt, 16% had a level below the label amount, and 7% had greater than 600 IU (15 μg)/qt (>150% of label). Even though the mean vitamin D₃ content did not differ statistically between milk types, a wide range in values was found among individual samples, from nondetectable [<20 IU (0.5 μg)/qt] for one sample to almost 800 IU (20 μg)/qt, with a trend toward more samples of whole milk having greater than 150% of the labeled content. On average, vitamin D₃ in 2% milk was higher in 2007 compared with in 2001 [473 vs. 426 IU (11.8 vs. 10.6 μg)/qt].     

深度-射线域偏移速度分析

根据波场外推理论和共角度成像条件，给出了基于深度-射线域共成像道集的偏移速度分析方法。该方法采用速度扫描技术，以共成像点道集同相轴拉平，即成像质量最优为准则提取速度修正量，可以采取沿构造层位或道集深度2种方式进行交互式速度分析。用Marmousi模型对该速度分析方法进行了沿深度方向和沿层位的偏移速度分析测验，结果表明，用该方法提取的速度修正量与预设的偏移速度误差几乎一致。     

Mass transfer coefficient and concentration boundary layer thickness for a dissolving NAPL pool in porous media

Analytical expressions for the time invariant, average mass transfer coefficient and the concentration boundary layer thickness applicable to dissolving single-component nonaqueous phase liquid (NAPL) pools in two-dimensional, saturated, homogeneous and isotropic porous formations are derived. Good agreement between predicted and experimentally determined time invariant average mass transfer coefficients is observed.     

Calculation of energy recovery and greenhouse gas emission reduction from palm oil mill effluent treatment by an anaerobic granular-sludge process

Conventional aerobic and low-rate anaerobic processes such as pond and open-tank systems have been widely used in wastewater treatment. In order to improve treatment efficacy and to avoid greenhouse gas emissions, conventional treatment can be upgraded to a high performance anaerobic granular-sludge system. The anaerobic granular-sludge systems are designed to capture the biogas produced, rendering a potential for claims of carbon credits under the Kyoto Protocol for reducing emissions of greenhouse gases. Certified Emission Reductions (CERs) would be issued, which can be exchanged between businesses or bought and sold in international markets at the prevailing market prices. As the advanced anaerobic granular systems are capable of handling high organic loadings concomitant with high strength wastewater and short hydraulic retention time, they render more carbon credits than other conventional anaerobic systems. In addition to efficient waste degradation, the carbon credits can be used to generate revenue and to finance the project. This paper presents a scenario on emission avoidance based on a methane recovery and utilization project. An example analysis on emission reduction and an overview of the global emission market are also outlined.     

A sharpness-dependent filter for recovering sharp features in repaired 3D mesh models

This paper presents a sharpness-based method for hole-filling that can repair a 3D model such that its shape conforms to that of the original model. The method involves two processes: interpolation-based hole-filling, which produces an initial repaired model; and post-processing, which adjusts the shape of the initial repaired model to conform to that of the original model. In the interpolation-based hole-filling process, a surface interpolation algorithm based on the radial basis function creates a smooth implicit surface that fills the hole. Then, a regularized marching tetrahedral algorithm is used to triangulate the implicit surface. Finally a stitching and regulating strategy is applied to the surface patch and its neighboring boundary polygon meshes to produce an initial repaired mesh model, which is a regular mesh model suitable for post-processing. During post-processing, a sharpness dependent filtering algorithm is applied to the initial repaired model. This is an iterative procedure whereby each iteration step adjusts the face normal associated with each meshed polygon to recover the sharp features hidden in the repaired model. The experiment results demonstrate that the method is effective in repairing incomplete 3D mesh models.     

Kinetic analysis of the thumb in jar-opening activity among female adults

Jar opening is commonly viewed as a challenging task for female adults in daily living. The thumb plays a particular role in grasping the jar lid and leading the turning activity through opposition to the other digits. This study measured and compared the force, torque and torque contribution of the thumb in the activity under ordinary grasp patterns and jar-holding positions. A steel jar-like cylinder was custom made to measure the force and torque generated simultaneously by thumb and wrist. Sixteen young females without a history of hand injury were recruited as subjects. The force and torque of the thumb were found to be influenced significantly only by the grasp pattern but its torque contribution was significantly affected only by the jar-holding position. However, overall torque was influenced by both the grasp pattern and the jar-holding position. The torque contribution of the thumb under the four different grasp patterns and jar-holding positions was found to range from 17.4% to 23.9%. The contribution ratios suggest that the thumb may offer a force equivalent to the other digits rather than just a counter force in this activity.     

iCluster软件叠前时间偏移模块的优化方法

对中国石化石油勘探开发研究院南京石油物探研究所iCluster地震成像软件系统中叠前时间偏移（PSTM）模块进行了性能剖析和调优。PSTM模块中，进程间通讯很少，理论上可以得到很好的加速比和可扩展性。由于存在大量的读写磁盘操作，导致CPU占用率很低，性能变差，一旦磁盘读写性能得到了很好的解决，性能将会大幅提升。此外，还发展了iCluster PSTM模块的多线程和混合并行方法。SMP集群上，通过多线程和混合并行方法不仅可以增加单节点的数据处理量，而且也很好地缓解了PSTM模块各进程对IO的竞争。另一方面，对原始代码中的热点循环进行了优化，实现了对代码的向量化，在某工区数据的测试中，性能提升了36.3%     

６４位集群计算平台波动方程叠前深度偏移的性能优化

详细介绍了iCluster波动方程叠前深度偏移软件系统所采用的集群并行计算策略,以及在６４位集群计算平台上开展的计算性能优化工作和取得的成果。给出了大量软件优化和性能测试结果,包括波动方程叠前深度偏移处理程序运行分析、MPI并行计算运行分析、不同编译器和编译参数测试对比、不同FFT算法效率测试对比、IA32和IA64平台软件运行效率对比测试及并行加速比测试等结果。以原来基于2.6GHZ Xeon系统上的软件运行效率作为基准,在基于1.4GHz Itanium2的系统上,经过优化的波动方程叠前深度偏移程序其计算性能提高了９倍左右。其性能的提高主要归功于３个因素,即６４位处理器硬件性能的提高、优化编译器的贡献和Intel MKL数学库中DFT程序的贡献。试验和分析表明,对于波动方程叠前深度偏移计算,基于千兆以太网的集群计算机系统可以在较大规模配置下,仍然能保持很高的并行加速比。面对数据规模和计算规模的挑战,向６４位计算平台的迁移是未来几年内地球物理计算的必然发展方向。IA64平台上软件计算性能的优化,既有巨大潜力,又有可观的经济价值。     

Insulinoma cell line (MIN6) adhesion and spreading mediated by Arg-Gly-Asp (RGD) sequence conjugated in thermo-reversible gel

We have functionalized gels with a putative cell-binding (-Arg-Gly-Asp-) (RGD) domain in an effort to regulate mammalian cell behavior in cells entrapped with gel. Adhesion molecules composed of Gly-Arg-Gly-Asp-Ser (GRGDS) peptides and cell recognition ligands were inculcated into thermo-reversible hydrogel composed of N-isopropylacrylamide, with a small amount of succinyl poly(ethylene glycol) (PEG) acrylate (MW 2000) used as a biomimetic extracellular matrix (ECM). The GRGDS-containing p(NiPAAm-co-PEG) copolymer gel was studied in vitro for its ability to promote cell spreading and to increase the viability of cells by introducing PEG spacers. Hydrogel lacking the adhesion molecules proved to be a poor ECM for adhesion, permitting only a 20% spread of the seeded cells after 10 d. When PEG spacer arms, immobilized by a peptide linkage, had been integrated into the hydrogel, conjugation of RGD promoted cell spread by 300% in a 28-d trial. In addition, in a serum-free medium, only GRGDS peptides conjugated with the spacer arm were able to promote cell spread.