荚果蕨多糖的组成分析及其抗氧化活性

提取分离从陕西省宁陕县采集的荚果蕨根状茎中的多糖成分,采用高效液相色谱法分析单糖组成,应用羟自由基清除法评价其抗氧化作用.荚果蕨根状茎经超声辅助水提取、醇沉、脱蛋白和透析后得多糖,将多糖水解并用1-苯基-3-甲基-5-吡唑啉酮(PMP)衍生化后进行高效液相色谱分析;同时,测定荚果蕨多糖对羟自由基的清除效果.荚果蕨根状茎中多糖由葡萄糖、半乳糖、木糖3种单糖组成,摩尔比为3.50∶1.39∶1,其中葡萄糖的含量明显高于其他单糖含量;荚果蕨根状茎中多糖能有效对羟自由基的半数抑制浓度(IC50)为0.74mg/mL,具有较强的抗氧化作用,且呈浓度依赖关系.本实验方法简便灵敏,结果准确可靠,为综合开发利用荚果蕨提供科学依据.     

海参胶原蛋白的提取及其基本成分的分析

提取海参中胶原蛋白并分析其基本成分.分别用碱解、酶解法提取胶原蛋白,Folin-酚试剂法测定多糖含量、蛋白含量,运用GC分析单糖成分.海参中多糖含量为14.35％,蛋白含量为0.989％.多糖的成分包括岩藻糖、甘露糖、半乳糖、葡萄糖,其中岩藻糖为主要单糖成分.本法简单,操作方便,实验灵敏,多糖得率高.     

香菇多糖L-2A的结构表征

从香菇子实体中提取纯化得到香菇多糖级分L-2A,利用紫外光谱、红外光谱、凝胶渗透色谱和气相色谱分析其结构特征.香菇多糖L-2A糖含量为90.14%;重均分子量是2.03×10 5道尔顿;具有D-葡萄吡喃糖构型,单糖组成主要是由吡喃型葡萄糖组成;香菇多糖L-2A多糖含有o-糖苷键,且主要是o-Ser连接方式;具有与刚果红结合的螺旋结构.香菇多糖L-2A为首次从香菇子实体中分离得到.     

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。     

气质联用法分析枸杞水溶性粗多糖中单糖组成

采用红外、气质联用技术分析了枸杞水溶性多糖中单糖组成及其含量.结果表明,枸杞多糖里含有的单糖包括阿拉伯糖,鼠李糖,木糖,甘露糖,半乳糖,葡萄糖,其含量比例为13.19∶3.41∶2.92∶10.53:18.92:9.82.     

黑龙江膜荚黄芪多糖及微量元素Fe、Zn、Cu和Mn的测定

采用水提醇沉法制备黄芪多糖提取物,苯酚-硫酸分光光度法测定多糖的含量,在0.00-0.14mg/mL线性范围内具有良好的线性关系,回收率在94.81%-103.50%.测定黄芪多糖含量为4.3%.采用校准曲线法,用空气-乙炔火焰原子吸收光谱法测定样品中Fe、Zn、Cu和Mn的含量,膜荚黄芪中微量元素含量较高.     

毛细管电泳法测定防风多糖中单糖的含量

在pH=12.80,电压为25kV,检测波长为254nm,以吲哚乙酸-磷酸钠体系为背景电解质的条件下,采用毛细管电泳对防风多糖中单糖进行了分离测定,各单糖的校准曲线线性关系良好,均大于0.994,测得防风多糖中半乳糖∶阿拉伯糖∶鼠李糖∶半乳糖醛酸=1∶ 2.3∶ 0.15∶4.8.     

原子吸收光谱法测定新疆不同居群大蒜中微量元素的含量

采用湿法消解处理大蒜样品,用原子吸收光谱法对新疆不同居群大蒜中Ca,Fe,Zn,Mg,Cu,Mn,Cr,Pb和Cd共九种微量元素的含量进行了测定,并进行了加标州收率实验.结果表明:不同居群大蒜中上述微量元素标准曲线的相关系数在0.994 4～0.999 8之间,呈现良好的线性关系;样晶测定结果的相对标准偏差(RSD)均不超过5.15%,各元素的加标回收率在99.4%～101.7%之间,测定结果准确可靠;新疆地产大蒜中对人体有益的微量元素含量较为丰富,不同样品中微量元素含量的差异一定程度上反映了南北疆之间地形地貌、气候、土壤、水文等环境要素的差异.     

富硒蛹虫草中硒多糖的分离与分析

在对人工栽培的富硒蛹虫草中分离提取了水溶性硒多糖,富硒蛹虫草硒多糖的分离纯化方法是采用水提醇沉工艺,粗硒多糖得率为5.76%。系统研究了富硒蛹虫草硒多糖的浸提、纯化、分离条件,苯酚硫酸法测定了富硒蛹虫草的多糖含量为47.5%,分子荧光法测定硒多糖中含硒量为92.3 mg·kg-1。     

分光光度法测定饲料用灌木中的淀粉含量

饲料用灌木中的淀粉用酶水解 ,水解产生的葡萄糖用蒽酮显色后分光光度法测定 ,由葡萄糖含量换算为淀粉含量。方法检出限为 2 μg/ m L,相对标准偏差为 1.4 %— 2 .2 % ,标准回收率在 97%— 10 3%之间。本方法用于几种灌木样品中淀粉含量的测定 ,结果令人满意。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.