非对称场流分离检测鲍内脏多糖

[目的]建立非对称场流分离检测鲍内脏多糖的方法。[方法]采用非对称场流分离系统与静态光散射、光电二极管阵列和示差折光检测器联用技术分离表征鲍内脏多糖。以0.05 mol/L Na NO3[含0.02%(W/V) Na N3]为流动相,研究横向流速和样品浓度对非对称场流分离多糖的影响,并利用动静态光散射测量鲍内脏多糖的分子特性(分子量、均方根旋转半径、分子构象、流体力学半径)。[结果]不同横向流速对多糖的分离表征有显著影响;一定范围内,不同多糖浓度对分离效果及分子特性结果无显著差异。鲍内脏多糖分子量为(25.40±1.78) k D,均方根旋转半径为(16.70±0.30) nm,流体力学半径为(143.23±15.49) nm,分子为无规则线团构象。[结论]非对称场流技术适用于鲍内脏多糖的分离检测。

芍药甘草汤自组装纳米粒的分离、表征及抗小鼠银屑病的研究

该研究旨在从芍药甘草汤(Shaoyao Gancao Decoction,SGD)中分离出自组装纳米粒(self-assembled nanoparticles,SAN),对其进行表征及含量测定,并进一步探究芍药甘草汤自组装纳米粒(SGD-SAN)对咪喹莫特诱导的小鼠银屑病的治疗作用。实验采用透析技术对SGD进行拆分,通过单因素试验对分离工艺进行优化。对优化后分离出的SGD-SAN进行表征,高效液相色谱仪检测各组没食子酸、芍药内酯苷、芍药苷、甘草苷、芹糖异甘草苷、异甘草苷、甘草酸的含量。药效实验设正常组、模型组、甲氨蝶呤组(0.001 g·kg^(-1))以及SGD组、沉淀组、真溶液组、SAN组(SGD及其拆分所得各组分别设低、中、高剂量:1、2、4 g·kg^(-1),以生药量计)。对皮损组织病理变化、炎症因子表达、脏器指数等指标进行检测。结果显示,除去沉淀的SGD溶液于13000 r·min-1离心30 min条件下透析4次得到的SAN性质稳定,为形态均一的球形纳米粒,粒径为(164.43±1.34)nm,多分散指数为0.28±0.05,Zeta电位为(-12.35±0.80)mV,所含活性成分占SGD全溶液70%以上。与模型组相比,SAN和SGD组的皮损评分、脾脏指数、炎症因子含量均显著降低(P<0.05或P<0.01),皮肤增厚、炎性细胞浸润等症状明显减轻。而沉淀组、真溶液组与模型组相比,均无明显改善。结果表明,SGD对咪喹莫特诱导的银屑病小鼠具有良好的治疗作用,且SAN组与SGD全溶液组基本等效,并呈剂量依赖性。由此认为,SGD发挥作用的主要形式为煎煮过程中活性成分聚集形成的SAN可通过降低多种炎症因子的表达水平、促进角质细胞正常分化、减少炎性细胞浸润,从而达到治疗小鼠银屑病的目的。

基于分离式表征的知识图谱推荐算法

基于知识图谱的推荐算法可以挖掘用户的潜在兴趣,有效解决推荐系统中的冷启动和数据稀疏性问题,然而现有基于知识图谱的推荐算法建模层面单一,很难挖掘到用户的深层兴趣。为此,提出一种基于分离式表征的知识图谱推荐算法。该算法首先利用分离式表征方法,将用户和物品的混合表征解耦成多个层面的分离式表征;然后采用图神经网络方法,利用用户-物品交互二分图和知识图谱中的邻域信息扩充用户和物品的分离式表征;同时,在分离式表征聚合邻域信息时,采用注意力机制和门控单元区分不同信息的重要性,自适应捕捉用户兴趣点。该算法细粒度刻画用户和物品表征,深度挖掘用户兴趣和物品特征,在三个公开数据集上与基准算法进行了对比实验,实验结果表明本文提出的算法在AUC、F1等指标上有明显提高。

淡水环境中可溶有机质研究进展

论述了淡水环境中可溶有机质(DOM)在分离与分析方法、来源与特征,以及环境意义等方面的研究进展。指出了在分离方法上,从XAD树脂分离到反渗透膜分离已经发展出各种分离技术;在分析方法上,现代波谱分析技术得到了广泛应用。DOM是由在来源、年龄、存在状态、后生改造等方面存在巨大差异的不同有机质混合构成的,因而呈现出十分复杂的非均质结构。DOM通过其自身的生物可利用性、改变有机污染物和重金属的生物可利用性及其耗氧能力影响环境质量,而且其自身的一些地球化学特征也能用来反映环境的变化特点。最后简述了湿地淡水环境中DOM的研究趋势和展望。

嵌段共聚物的临界条件液相色谱分离与表征

嵌段共聚物是由两种或两种以上不同性质的聚合物链段通过共价键连接形成的特殊聚合物。它可以结合构成嵌段的不同种类聚合物的性质,得到性能比较优越的功能性聚合物材料,因此越来越受到人们的重视。然而,嵌段共聚物的分离和表征一直都是一项颇具挑战性的工作。临界条件液相色谱(liquid chromatography at the critical condition,LCCC)作为一种新型的液相色谱分离技术,可以使嵌段共聚物中的某种嵌段处于"色谱不可见"(chromatographic invisible)状态,不会影响整个聚合物的保留时间,从而根据嵌段共聚物中其他嵌段长度来分离嵌段共聚物。本文介绍了LCCC分离法的分离原理与实现途径,较为系统地综述了LCCC分离表征嵌段共聚物的近期研究进展,并对该方法目前存在的问题及今后发展前景进行了探讨。

Characterization of Pigeon Paramyxoviruses (Newcastle disease virus) Isolated in Kazakhstan in 2005

Isolates of Newcastle disease virus (NDV) from deceased wild and domestic pigeons in Kazakhstan were obtained from the Almaty region during 2005 and were genotypically analyzed by using reverse transcription polymerase chain reaction (RT-PCR) with primers specific to the viral fusion (F) protein gene. Part of the amplified F protein DNA product (nucleotide sequence 47-422) and the deduced amino acid sequences were compared phylogenetically with those from strains previously reported in other geographic regions. Phylogenetic analysis indicated that the Kazakhstanian pigeon paramyxovirus type 1 (PPMV-1) isolates belong to genotype VI or 4bii. To our knowledge, this is the first reported VI isolates that possess the sequences of 112 GKRQKR116* F117 within the F0 protein. The information is fundamental to improving the efficiency of control strategies and vaccine development for NDV.

Multi-mode Coherent-Entangled State Representation and Its Applications

We introduce the so-called coherent-entangled state (CES) in the four-mode Fock space,which makesup a new quantum mechanical representation owing to completeness relation and orthogonal property.Its standardSchmidt decomposition and experimental generation using beam-splitter (BS) are proposed.In addition,its applicationsin quantum optics are presented.Finally,we extend it to multi-mode case and discuss some applications,too.

Isolation, identification and characterization of cadmium-resistant Pseudomonas aeruginosa strain E_1

Strain E1 with resistance to 18 mmol/L cadmium （Cd）, isolated from Cd-contaminated soil was identified by morphological observation, biochemical and physiological characterization and 16S rDNA sequence analysis. The resistance to heavy metals Cd, Cu, Co, Mn, Pb, Zn and 12 antibiotics was examined. The ability of removing Cd from solution was studied. The characterizations show that strain El is affiliated to Pseudomonas aeruginosa （P aeruginosa）. Strain E1 has high resistance to heavy metals and the order is found to be Cd〉Mn〉Zn〉Cu〉Pb〉Co in solid media. Strain E1 also exhibits the resistance to 12 antibiotics. Both living and non-living cells of strain E1 can remove Cd from solution, and living cell has better biosorption than non-living cell.

Purification and Characterisation of a Coffee Pulp Tannase Produced by Penicillium verrucosum

Tannase was extracted from a new fungal strain Penicillium verrucosum using coffee pulp as a substrate by solid state fermentation. The extracellular tannase was purified using Sephadex G-100 to 86.02 folds with 34.3% yield and a single band corresponding to 81 kDa was observed in SDS-PAGE. Tannase was immobilized on alginate by entrapment method. The graphical analysis of the effect of the substrate concentration on the tannase activity yielded a Km of 48.88 mM and a Vmax of 169.49 U/mL. The optimum temperature and pH of the enzyme were 30 ℃ and pH 5. The thermal stability, as well as stability over a wide range ofpH, was significantly improved by the immobilization process. The activity was enhanced by Mg^2＋ （23.5%） and K^＋ （5.3%）, whereas Zn^2＋, Cu^2＋, Ca^2＋, NH^4＋ and Hg^2＋ inhibited tannase activity. Maximum substrate bioconversion （58.94%） from tannic acid to gallic acid and tea cream solubilisation （32.82%） was achieved using immobilized tannase. The extracellular tannase produced by P. verrucosum showed distinctive characteristics such as monomeric structure and activation by Mg^2＋, suggesting a new kind of fungal tannase with biotechnological potential.

Molecular characterization of Acidithiobacillus ferrooxidans strains isolated from different environments by three PCR-based methods

PCR-based DNA fingerprinting, REP-PCR(repetitive element PCR), RAPD(randomly amplified polymorphic DNA) and16 S r DNA sequence analyses were used to characterize 23 Acidithiobacillus ferrooxidans strains isolated from different environments.(GTG)5 and BOXA1 R primer were selected for REP-PCR. Twenty arbitrary primers were used for RAPD to acquire DNA profiles from A. ferrooxidans. Both RAPD and REP-PCR produce complex banding patterns and show good discriminatory ability in differentiating closely related strains of A. ferrooxidans. The strains are clustered into 4 or 5 major groups and reveal genomic diversity using(GTG)5-PCR, BOX-PCR and RAPD analysis. Phylogenetic tree based on 16 S r DNA sequences of 23 strains and related strains shows that they are clustered into two distinct groups. Twelve strains are highly related to a new Acidithiobacillus named Acidithiobacillus ferrivorans. The results indicate that PCR-based methods are effective in revealing genetic diversity among A. ferrooxidans.

Isolation, Modification and Characterization of Finger Millet （Eleucine coracana） Starch

Isolated finger millet （Eleucine coracana） starch was subjected to different modifications （hydrothermal, acidic and enzymatic） and characterized in terms of yield, moisture, protein, ash, bulk density, swelling power, solubility, sediment volume, colour, gel consistency, water binding capacity （WBC）, pasting properties, freeze thaw stability and paste clarity, and compared with native starch. Moisture content ranged from 4%-5%. Protein and ash content were lowest in case of acid modified starch （AMS）. Hydrothermally modified starches （HTMS） showed maximum water binding, peak viscosity and syneresis. Swelling power was decreased for all modifications. Solubility and color （a and b values） decreased for AMS and EMS. However, L values increased with all modifications. EMS showed maximum bulk density, swelling power, solubility, and sediment volume and gel consistency. Paste clarity decreased with storage period and found maximum for EMS.

Characterization and processing of talc-magnesite from the Zinelbulak deposit

The characteristics of talc-magnesite from the Zinelbulak deposit(Uzbekistan) were investigated via X-ray diffraction, differential thermal analysis,infrared spectroscopy and optical microscopy.The mineralogical composition of the Zinelbulak talc-magnesite consists of 52 wt.%talc,43 wt.%carbonates and 5 wt.%of the iron-containing minerals magnetite,siderite and chlorite.Petrographic analysis confirmed the presence of carbonates in two forms:magnesite and breunnerite.Grindability tests revealed that talc and magnesite particles are completely separated after a grinding process carried out for 10～12 min.The distribution of the yield of talc and magnesite,as a function of the particle size,shows an irregular feature in that a comparatively coarser sample(>0.1 mm) is richer in magnesite and poor in talc while a comparatively finer sample(<0.1 mm) has a composition poorer in magnesite.The dressability of the Zinelbulak talc-magnesite was tested using conventional gravity concentration,flotation and electromagnetic separation.Gravity concentration was found to be the most economic initial process for the complete separation of magnesium carbonate and talc.Subsequent flotation and magnetic separation techniques could further increase the yield of high quality magnesite and talc.Refractory samples prepared by heating the separated magnesite at 1600℃for 2 h met the State Standards for refractory materials.

Isolation and characterization of venom from nematocysts of jellyfish Rhopilema esculentum Kishinouye

The present work is the first report of the biochemical characterization of the venom from nematocysts of the jellyfish Rhopilema esculentum Kishinouye. The nematocysts were isolated by autolysis and centrifugation and separated by flow cytometry. Four types of nematocysts were identified： mastigophores, euryteles, and atrichous and holotrichous isorhiza. SDS-PAGE and amino acid analyses demonstrated that most of the proteins in the nematocyst extract were between 10 kDa and 40 kDa, and that glutamic acid was the main amino acid. A hemolytic activity assay showed that the activity of the nematocyst venom （RNV） was strongest in Tris-HCl buffer （50 mmol/L, pH 7.8, 5% glycerol, 0.5 mmol/L EDTA, 0.1 mol/L NaC1）. The hemolytic activity was related to protein concentration and the HU50 against chicken erythrocytes was 0.91 μg/mL.

Purification and characterization of cold-active endo-1,4-β-glucanase produced by Pseudoalteromonas sp. AN545 from Antarctica

A bacterium hydrolyzing carboxymethylcellulose, isolated from Antarctic sea ice, was identified as Pseudoalteromonas sp. based on 16S rDNA gene sequences and named as Pseudoalteromonas sp. AN545. The extracellular endo-1,4-β-glucanase AN-1 was purified successively by ammonium sulfate precipitation, DEAE-Sepharose ion exchange chromatography and Sephadex G-75 gel filtration chromatography. The molecular mass of AN-1 was estimated to be 47.5 kDa utilizing SDS-PAGE and gel chromatography analysis. AN-1 could hydrolyze caboxymethylcellulose, avicel and β-glucan, but not cellobiose, xylan and p-Nitrophenyl-β-D-glucopyranoside. The optimal temperature and pH for the β-glucanase activity of AN-1 were determined to be at 30℃ and pH 6.0, respectively. AN-1 was stable at acidic solutions of pH 5.0-6.5 and temperatures below 30℃ for 1 h. Moreover, the specific activity was enhanced by Ca2＋ and Mg2., and inhibited by Cu2＋. The kinetic parameters Michaelis constant （Km） and maximum velocity （Vmax） of AN-1 were 3.96 mg/mL and 6.06×10-2 mg/（min.mL）, respectively.

A WEIGHTED GENERAL DISCRETE FOURIER TRANSFORM FOR THE FREQUENCY-DOMAIN BLIND SOURCE SEPARATION OF CONVOLUTIVE MIXTURES

This letter deals with the frequency domain Blind Source Separation of Convolutive Mixtures (CMBSS). From the frequency representation of the "overlap and save", a Weighted General Discrete Fourier Transform (WGDFT) is derived to replace the traditional Discrete Fourier Transform (DFT). The mixing matrix on each frequency bin could be estimated more precisely from WGDFT coefficients than from DFT coefficients, which improves separation performance. Simulation results verify the validity of WGDFT for frequency domain blind source separation of convolutive mixtures.

Molecular and in vitro Characterization of Field Isolates of Bovine Herpesvirus-1

Bovine Herpesvirus-1 (BoHV-1) is distributed worldwide and is a major pathogen in cattle, being the causal agent of a variety of clinical syndromes. The aim of this study was to isolate and to characterize (molecular and biological characterization) BoHV-1 from 29 immunosuppressed animals. It was possible to obtain 18 isolates, each from a different animal, such as from the respiratory and reproductive tracts. In some cases the cytopathic effect was visible 12 hours post-inoculation, and became characteristic after 36-48 hours. Biological characteristics were evaluated and compared with Iowa and Colorado-1 reference strains, and differences were found in plaque size, virus titer measured by TCID50 and PFU/mL, and one step virus curves. These results showed that some isolates had a highly virulent-like behavior in vitro, compared to the reference strains, with shorter eclipse periods, faster release of virus into the supernatants, and higher burst size and viral titer. There were no differences in glycoprotein expression of BoHV-1 isolates, measured by Western blot on monolayers. Moreover, using restriction endonucleases analysis, most of the viruses were confirmed as BoHV-1.1 and just one of them was confirmed as BoHV-1.2a subtype. These findings suggest that some wild-type BoHV-1 isolates could be useful as seeds to develop new monovalent vaccines.

Characterization and separation of pyrite from Abu Tartur black shale

This work aimed for pyrite separation from Abu Tartur black shale as a source of sulfur to be an added economic value of Abu Tartur area. The considered samples in the present work were collected from a core drilled in Abu Tartur plateau representing the pyrite-rich black shale of the U. Cretaceous age, Sample characterization was carried out using petrographic microscope, XRD, DTA/DTG, C/S and XRF techniques. Clay minerals, silt-sized quartz, calcite, and hematite were the main minerals associating pyr- ite （5.34g）. Liberation behavior of the sample was about 80% below 5 μm. Sample processing was achieved through one-day soaking followed by classification using I inch Mozley hydro-cyclone where about 35.5% by weight went to underflow and 64.5% went to overflow. The underflow product was subjected to an advanced gravity separation process using SB-40 Falcon Concentrator through a CCD statistical design prepared by Design-Expert 6.0 software proposed to opti- mize the separation process through a study for the effects of frequency （Hz） and water pressure （Psi） on both assay and recovery of the sulfur-rich heavy fraction. A heavy concentrate weighed 10.90% with inorganic sulfur content reached 11.37% （21.24% pyrite） with overall recovery （50.01%） was obtained after two cleaning at the optimum conditions.

Isolation and Characterization of a Bensulfuron-Methyl-Degrading Strain L1 of Bacillus

The objectives of this study were to isolate a bensulfuron-methyl （BSM）-degrading strain of Bacillus spp. and to evaluate its effectiveness in remediation of a BSM-contaminated soil. A BSM-degrading bacterium, strain L1, was successfully isolated in this study. Strain L1 was identified as Bacillus megaterium based on its morphological, physiological, and biochemical properties, G＋C content, phylogenetie similarity of 16S rDNA, and fatty acid composition. Two experiments were used to examine BSM degradation by strain L1. When BSM was used as a sole carbon source in a mineral salt medium, the average degradation rate of BSM by strain L1 was 12.8%, which suggested that the strain was able to utilize BSM as a sole carbon and energy source. Supplement of yeast extract （200 mg L^-1） significantly （P ≤ 0.01） accelerated the degradation of BSM by strain L1. Ahnost complete degradation （97.7%） of BSM could be achieved in 84 h with addition of yeast extract. In addition, in a sterile soil with 50 mg L^-1 BSM, BSM degradation rate by strain L1 was 94.3% in 42 d, indicating the potential of using microbes for the remediation of BSM-contaminated soils in fields.

Characterization of tricalcium phosphate solubilization by Stenotrophomonas maltophilia YC isolated from phosphate mines

The phosphate solubilizing characteristics of a strain YC, which was isolated from phosphate mines (Hubei, China), were studied in National Botanical Research Institute’s phosphate (NBRIP) growth medium containing tricalcium phosphate (TCP) as sole phosphorus (P) source. The strain YC is identified as Stenotrophomonas maltophilia (S. maltophilia) based upon the results of morphologic, physiological and biochemical characteristics and 16S rRNA sequences analysis. The results show that the strain S. maltophilia YC can solubilize TCP and release soluble P in NBRIP growth medium. A positive correlation between concentration of soluble P and population of the isolate and a negative correlation between concentration of soluble P and pH in the culture medium are observed from statistical analysis results. Moreover, gluconic acid is detected in the culture medium by HPLC analysis. It indicates that the isolate can release gluconic acid during the solubilizing experiment, which causes acidification of the culture medium and then TCP solubilization. S. maltophilia YC has a maximal TCP solubilizing capability when using maltose as carbon source and ammonium nitrate as nitrogen source, respectively, in NBRIP growth medium.

Characterization of a newly Isolated Bacterium Pandoraea sp.B-6 capable of degrading kraft Lignin

A newly isolated bacterium was screened out for its survival on medium with 6 000 mg/L kraft lignin as the sole carbon source and energy, and identified as Pandoraea sp. by 16S rRNA gene sequence analysis. The biodegradation experiment was carried out in mineral salt medium, containing 5 000 mg/L kraft lignin as only carbon and energy at pH 8.0 and 30℃. Under these conditions, significant reduction in color and lignin content by the strain was observed after incubation for 5 d. The strain attains maximum reduction capability in color （44.6%） and lignin content （39.9%） within 5 d of incubation, and reduced chemical oxygen demand（COD） from initial concentration 7 399 to 3 980 mg/L at maximum reduction level of 46.2% on the 4th day. The total ion chromatograph （TIC） of compounds presented in the chloroform extract of control and bacterial treated samples shows the formation of several lignin-related aromatic compounds including some small molecular lignin fragments, indicating a strong destruction in the lignin structure.