硫酸酯化螺旋藻多糖的制备与IR表征

微波法提取的螺旋藻多糖,经十六烷基三甲基溴化铵盐溶液分级,得不同级分螺旋藻多糖S1、S2、S3。通过浓硫酸法和氯磺酸甲酰胺法合成了螺旋藻硫酸酯化多糖SL1、SL2和SL3,用IR对产物结构作了表征。     

灵芝多糖结构及其组成研究

采用沸水回流法从赤灵芝子实体中提取多糖,经Sevage法除蛋白,乙醇沉淀,离心、流水透析、浓缩、冻干后得灵芝多糖,单糖经乙酰化处理进行外标法定量,并利用苯酚-硫酸法、紫外、红外及X衍射光谱法、凝胶分子排阻色谱-蒸发散射检测器法、气相和气质谱色谱法进行多糖组分、含量、结构和分子量分析研究,结果表明： 灵芝多糖为米黄色,得率为2%左右,其含量≥43%,红外光谱显示灵芝多糖结构主要为β-糖甘键连接的吡喃型葡聚糖,其多糖的主要单糖组分为葡萄糖,含量为89%左右,并含有其他少量的单糖组分D-阿拉伯糖、D-木糖、D-甘露糖、D-半乳糖。其多糖主要为同均糖,多糖为非晶型结构,分子量主要分布在8×104～2×105之间,分子质量主要为2×105的生物大分子。     

用气相色谱和红外光谱对羧甲基化南瓜多糖结构的研究

采用超声辅助法提取南瓜多糖并对其进行分离和羧甲基化;邻苯三酚自氧化法测定羧甲基南瓜多糖对超氧阴离子自由基的清除作用;气相色谱法、红外光谱对南瓜粗多糖及其组分AP1的化学结构进行了分析.结果表明,羧甲基南瓜多糖能有效清除超氧阴离子自由基,并随着浓度的增加清除作用增强.该结果提示羧甲基南瓜多糖具有抗氧化性.气相色谱证明南瓜多糖由阿拉伯糖、鼠李糖、核糖、甘露塘、果糖、半乳糖、葡萄糖组成.南瓜AP1多糖由阿拉伯糖、鼠李糖、核糖、果糖、半乳糖、葡萄糖组成.红外光谱分析证实南瓜多糖具有糖类物质的特征吸收峰,同时存在呋喃环和吡喃环.     

2D NMR对刺五加种子中的一个三萜皂苷进行结构解析

通过质谱、核磁共振谱并结合文献对一个三萜皂苷hederagenin 3-O-β-D-glucuronopyranpside进行结构解析. 通过2D NMR（HMQC、HMBC）对其进行了NMR全归属.
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超声波强化提取对茯苓水溶性多糖结构影响的研究

以茯苓菌核为原料,采用正交实验法确定超声波辅助热水浸提茯苓水溶性多糖的最佳提取条件,并对超声波辅助提取中药多糖的机理进行初步研究。用苯酚硫酸法测定糖含量,傅立叶变换红外光谱仪(FTIR)分析糖类官能团,气相色谱法测定单糖组成,原子力显微镜观察多糖结构,并将测定结果与传统热水法浸提所得茯苓多糖进行对比。实验结果表明:采用超声波辅助热水浸提可以使水溶性茯苓多糖的提取率达到2.71%(传统热水浸提法提取率为1.49%),传统热水浸提得茯苓多糖(PPTH)与超声波辅助热水浸提得茯苓多糖(PPUH)具有相同的单糖组成,都包含核糖、木糖、甘露糖、果糖、半乳糖和葡萄糖,二者的红外吸收谱也基本相同,原子力显微镜扫描分析显示,PPTH整体呈现网状结构,而PPUH主要以长短不一的近棒状结构存在。     

红外光谱结合有效成分分析在锁阳多糖提取分离中的应用

利用红外光谱技术结合有效成分含量测定方法对提取分离过程中的锁阳多糖进行了研究,以期探讨一种快速简便分析含量变化的新方法。红外光谱图显示光谱变化主要在1 800~800cm~(-1),对此波段进行二阶导数处理,确定用吸光度比A_(1 026)/A_(3 404)考察多糖相对含量变化,与苯酚-硫酸法测定的多糖含量进行对比分析。结果显示,不同工艺过程中多糖含量有明显变化,吸光度比法可快速判断多糖含量的变化情况,与苯酚-硫酸法测定的多糖含量结果一致,在优化工艺过程参数时提供方向性参考。红外光谱结合含量测定,可为下一步制定药效成分的提取分离方案提供定性定量分析依据。     

亚甲蓝与硫酸化茯苓多糖相互作用机理的研究

为从分子水平认识硫酸化多糖分子与小分子之间相互作用的机理,文章采用氯磺酸-吡啶法(Wolfrom法)对茯苓多糖进行结构修饰,制得硫酸化茯苓多糖(SP)。通过理论模型测得亚甲蓝(MB)与SP最大结合数N=54,结合常数K=1.563×106,考察了反应体系中MB/SP摩尔比、NaCl、乙醇、羟丙基-β-环糊精以及Triton X-100对相互作用的影响。探讨了MB与SP相互作用产生变色反应的机理,认为其是在MB 与SP大分子间发生静电相互作用的基础上,结合态MB分子之间的疏水相互作用所引起的。     

三种多糖的光谱鉴定、化学改性及活性

研究了壳聚糖、茯苓多糖、魔芋甘露聚糖的红外光谱、Ｈ核磁共振光谱。对三种多糖进行了羧甲基化改性,研究了这种化学改性与抗肿瘤等活性的关系。     

益母草多糖的抗氧化性

测定益母草多糖含量和研究其多糖的抗氧化性.利用水提醇沉法提取粗多糖,并利用Sevage法脱蛋白对其进行纯化;采用苯酚-硫酸法测定益母草多糖样品中纯多糖的含量并采用邻苯三酚自氧化法和水杨酸法分别研究益母草多糖清除O2-·和·OH的效果.益母草提取所得多糖样品中纯多糖含量达48.5％,益母草多糖具有较强的清除O2-·和·OH的作用.     

新药硫酸头孢匹罗的NMR研究

应用1D NMR、2D NMR （COSY、HMQC、HMBC、NOESY）及脉冲梯度场2D NMR技术[gHSQC（¹H-¹⁵N）、gHMBC（¹H-¹⁵N）]深入研究了第四代新型超广谱头孢菌素类抗生素硫酸头孢匹罗的结构,并首次对其¹H NMR、¹³C NMR谱和¹⁵N NMR谱的信号进行了全归属,通过NOESY实验对其立体结构提供有力依据.     

刚体与SPH耦合的三维数值方法研究

 研究了刚性体与SPH（Smoothed Particle Hydrodynamics）方法相耦合的计算方法和技术,以此技术为核心,在原有三维综合拉氏程序CL3D的基础上,研制了适用于斜侵彻问题数值研究的刚性弹体与SPH靶体耦合计算的拉氏三维数值模拟程序CRSPH3D。针对金属材料编入了Johnson-Cook本构模型计算模块,针对混凝土材料编入了Johnson-Holmquist本构模型及与之配套的损伤模型和状态方程等的计算模块。用研制的计算程序对弹体分别正碰和斜碰穿透中厚铝靶和侵彻厚混凝土靶的过程进行了数值模拟计算和分析。结果表明,对于铝靶穿透问题,模拟计算得到的弹体剩余速度、弹体动能损失和贯穿图像与实验结果符合得较好。对于混凝土靶的侵彻问题也得到了与实验现象一致的、定性合理的图像。     

Evaluation of the inner ear by 3D fast asymmetric spin echo (FASE) MR imaging: phantom and volunteer studies

The 3D fast asymmetric spin echo (FASE) method combines the half-Fourier technique and 3D fast spin echo (FSE) sequence. The advantage of this method is that it maintains the same spatial resolution as FSE while markedly reducing the imaging time. The purpose of the present study was to evaluate the usefulness of the 3D FASE technique in displaying the inner ear structure using phantom and volunteer studies. 3D FSE sequence images were obtained for comparison, and the optimum 3D FASE sequence was investigated on a 1.5T MR scanner. The results of phantom experiments showed increased signal-to-noise ratio (SNR) with prolonging repetition time (TR) on both 3D FASE and 3D FSE sequences. Although the SNR of 3D FASE images was 20-25% lower than that of 3D FSE images with the same TR, the SNR per minute with 3D FASE was about twice that with 3D FSE. On 3D FASE images, a higher spatial resolution was obtained with 2- or 4-shot images than with single-shot images. However, no significant difference was observed between 2-shot and 4-shot images. In the volunteer study, 3D FASE images using a TR of 5000 ms and an effective echo time (TEeff) of 250 ms showed a high SNR and spatial resolution and provided excellent contrast between cerebrospinal fluid and nerves in the internal auditory canal. The highest contrast was achieved in the 2-shot/2 number of excitations sequence. 3D FASE provides the same image quality as 3D FSE with a significant reducing in imaging time, and gives strong T2-weighted images. This method enables detailed visualization of the tiny structures of the inner ear.     

Preoperative fast MRI of brain tumors using three-dimensional segmented echo planar imaging compared to three-dimensional gradient echo technique

The purpose of this study was to compare the diagnostic efficacy of a newly developed T(1)-weighted three-dimensional segmented echo planar imaging (3D EPI) sequence versus a conventional T(1)-weighted three dimensional spoiled gradient echo (3D GRE) sequence in the evaluation of brain tumors. Forty-four patients with cerebral tumors and infections were examined on a 1.0 T MR unit with 23 mT/m gradient strength. The total scan time for the T(1) 3D EPI sequence was 2 min 12 s, and for a conventional 3D GRE sequence it was 4 min 59 s. Both sequences were performed after administration of a contrast agent. The images were analyzed by three radiologists. Image assessment criteria included lesion conspicuity, contrast between different types of normal tissue, and image artifacts. In addition, signal-to-noise and contrast-to-noise-ratio (C/N) were calculated. The gray-white differentiation and C/N ratio of 3D EPI were found to be inferior to conventional 3D GRE images, but the difference was not statistically significant. In the qualitative comparison, lesion detection and conspicuity of 3D EPI images and conventional 3D GRE images were similar, but a tow-fold reduction of the scanning time was obtained. With the 3D EPI technique, a 50% scan time reduction could be achieved with acceptable image quality compared to conventional 3D GRE. Thus, the 3D EPI technique could replace conventional 3D GRE in the preoperative imaging of brain.     

三维多物质弹塑性流体动力学Euler方法的并行算法研究及程序测试

 并行计算是解决爆炸与冲击问题大规模数值模拟最有效的手段之一。针对Euler方法并行程序设计的复杂性,阐述了三维多物质弹塑性流体动力学程序MMIC-3D并行设计的总体策略,基于消息传递接口(MPI)设计出相应的PMMIC-3D并行程序,并提出了一套实用的程序测试方案。结合聚能射流形成过程的数值模拟算例,在八节点的集群上测试了加速比、并行效率及可扩放性,分析了影响并行性能的因素。     

Short T2 contrast with three-dimensional ultrashort echo time imaging

There is increasing interest in imaging short T2 species which show little or no signal with conventional magnetic resonance (MR) pulse sequences. In this paper, we describe the use of three-dimensional ultrashort echo time (3D UTE) sequences with TEs down to 8 μs for imaging of these species. Image contrast was generated with acquisitions using dual echo 3D UTE with echo subtraction, dual echo 3D UTE with rescaled subtraction, long T2 saturation 3D UTE, long T2 saturation dual echo 3D UTE with echo subtraction, single adiabatic inversion recovery 3D UTE, single adiabatic inversion recovery dual echo 3D UTE with echo subtraction and dual adiabatic inversion recovery 3D UTE. The feasibility of using these approaches was demonstrated in in vitro and in vivo imaging of calcified cartilage, aponeuroses, menisci, tendons, ligaments and cortical bone with a 3-T clinical MR scanner. Signal-to-noise ratios and contrast-to-noise ratios were used to compare the techniques.     

发展3D NOE-NOE分析软件的策略

本文发展了一种对3D形式的2D NOE分析软件,提出了一种可表达2D NOE与3D NOE-NOE峰值之间关系的数学模型,并考虑了存储空间与CPU时间的平衡.     

三维显微图像复原及点扩散函数的研究

三维显微图像去卷积计算量巨大,运算时间长。评价和分析了三维点扩散函数、散焦像、光学切片以及不同三维点扩散函数去卷积的复原图像,进一步证明了散焦光信息对焦面像的干扰,主要来自于焦面像两侧附近的散焦像。提出了折中选择三维PSF的空间大小,可以获得良好的复原效果,并且减少运行时间。提出了频谱图均值的新概念,作为评价图像清晰及模糊程度的标准,并运用于散焦像、光学切片以及复原结果图的评价。     

A flow control study of a supersonic mixing layer via NPLS

The flow control of a supersonic mixing layer was studied in a supersonic mixing layer wind tunnel with convective Mach number (Mc) at 0.5. The passive control of the mixing layer was achieved by perturbation tapes on the trailing edge of the splitter plate. The control effects of 2D and 3D perturbation tapes with different sizes were compared. The mixing layer was visualized via NPLS, and the transient fine structures were identifiable in NPLS images, which were used to analyze the effects of flow control. The results show that the 2D tapes can enhance the 2D characteristic of the mixing layer, delaying mixing layer transition; and the 3D tapes can enhance the 3D characteristic of the mixing layer, advancing mixing layer transition. 3D structures of the mixing layer were visualized, and the H-type Λ vortexes were found with 3D tapes control.     

荷电膜渗透传质过程的计算机模拟：一价离子的传递

以渗透理论的方法研究一价离子通过荷电膜的传质机理,用计算机编程模拟一价带电离子通过荷电膜的过程以研究荷电膜中导电性能和荷电组分含量的关系.模拟结果表明,对于二维格栅体系在荷电组分含量为0.4～0.6时,膜导电性能存在渗透突跃现象;而对于三维格栅体系则在0.1～0.2时存在渗透突跃现象,此结果和MontoCarlo的二维、三维随机模拟结果比较接近.由于实际的荷电膜也可看作为三维格栅体系,因此,可用三维格栅体系程序对不同荷电分率膜的电导数据进行拟合,结果表明,对于实际的磺化聚苯硫醚(SPPS)/聚醚砜(PES)共混膜,当荷电组分SPPS的分率达到0.144时,共混膜即会从不良导体变为良导体,显然该值落在理论值0.1～0.2,因此,理论模拟结果与实际荷电膜传质的实验数据相吻合.