Studied on the interactions of antibody-porphyrin by circular dichroism and ultraviolet-visible spectrophotometry

Circular dichoism and UV-vis measurements were used to study the interaction between porphyrin and monoclonal antibodies ( McAbs). McAbs-porphyrin complex formation is usually accompanied by significant bathochromic shift and hyperchromicity changes of the absorption maxima in the porphyrin soret band region. Induced CD spectra in the same region (350 similar to 450 nm) were detected upon complex formation. They follow Lamb-Beer's law and exhibit isosbestic behavior. Both the UV-Vis and induced CD spectra of the antibody: porphyrin complex remain unchanged over a broad pH range ( pH 6 similar to 11), indicating remarkable stability of the complex and reflecting the dominant role of hydrophobic interaction between the hapten benzophenone and the antibody combining site.

FACTOR-ANALYSIS SPECTROPHOTOMETRY FOR THE SIMULTANEOUS DETERMINATION OF VALENCE STATES OF METALS

Two M(n+)-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol systems for the simultaneous determination of the valence states of Cr and Fe using factor analysis were studied. (1) At pH 4.0, Cr(III) and Cr(VI) react with the reagent to form stable complexes and a slight difference in the wavelengths of maximum absorption (lambda(max.)) between the two complexes is observed when the sodium lauryl sulfate, which also acts as a solubilizing and sensitizing agent, is added, viz., 590 nm for Cr(III) and 593 nm for Cr(VI) complexes. (2) In the presence of ethanol, both Fe(II) and Fe(III) form 1:2 complexes with the reagent at pH 2.5-3.5 and the lambda(max.) of the Fe(II) and Fe(III) complexes is at 557 and 592 nm, respectively. In the target transformation factor analysis, the K coefficients calculated from the standard mixtures by classical least-squares analysis and a non-zero intercept added to each wavelength are used as the target vector instead of the pure component standards; this can decrease the analysis errors introduced by the interaction between the two species and by deviations from Beer's law.

Effect of alumina and chromium interlayers on microstructures and optical properties of thin Ag films on glass substrates

Effects of alumina and chromium interlayers on the microstructure and optical properties of thin Ag films are investigated by using spectrophotometry, x-ray diffraction and AFM. The characteristics of Ag films in Ag/glass, Ag/Al2O3/glass and Ag/Cr/glass stacks are analysed. The results indicate that the insertion of an Al2O3 or Cr layer decreases the grains and influences the reflectance of Ag films. The reflectance of the Ag film can be increased by controlling the thickness of alumina interlayer. The stability of Ag films is improved and the adhesion of Ag films on glass substrates is enhanced by alumina as an interlayer.

Influence of oxygen plasma treatment on properties of ZrO2 films prepared by e-beam evaporation techniques

Zirconia films were prepared by e-beam evaporation, and oxygen plasma treatment was used to modify film properties. Spectrophotometry, x-ray diffractometry (XRD), and atomic force microscopy were used to characterize refractive index, extinction coefficient, rnicrostructure, and surface roughness, respectively. The experimental results indicate that both refractive index and extinction coefficient of the films were reduced slightly after oxygen plasma treatment, with the decrease of intrinsic stress and surface roughness. From XRD spectra, the intensity decrease of the T(110) diffraction peak was clearly observed after the treatment, which was caused by the restructuring of the film atoms. (C) 2008 Elsevier Ltd. All rights reserved.

Effect of beta-glucan on activity of antioxidant enzymes and Mx gene expression in virus infected grass carp

The effects of beta-glucan, an immunostimulatory agent, on the superoxide dismutase (SOD) and catalase (CAT) activities of erythrocytes and Mx gene expression were studied from grass carp that were challenged with grass carp hemorrhage virus (GCHV). The SOD and CAT activities in erythrocytes and Mx gene expression in spleen from the fish were detected by spectrophotometry and RT-PCR, respectively. Negative control fish were injected with PBS; positive control groups were injected with either P-glucan or GCHV only; and the experimental groups were pre-injected with beta-glucan 15 days prior to injection with GCHV. The results show that the SOD and CAT activities were higher in fish injected with beta-glucan for 15 days than the negative control group injected with PBS. The SOD and CATactivities significantly decreased when the fish were challenged with GCHV, but it was higher in the group pre-treated with beta-glucan than in infected fish not pre-treated, 15 days after GCHV infection. Mx gene expression levels increased during the early stages (at 12 h and 36 h) of GCHV infection, and it remained at higher levels from the 6th till the 10th day in the beta-glucan pre-treated group, but it was failing from the 6th day in the beta-glucan untreated group. The GCHV-infected group pre-treated with P-glucan had a higher survival rate (60%) than the group not pre-treated with P-glucan (20%), suggesting that beta-glucan possesses or enhances anti-viral responses. (C) 2009 Elsevier Ltd. All rights reserved.

工艺流程中高浓定影液酸度的流线分析方法研究

每种酸碱指示剂在其变色PH范围内都有一个明显的颜色变化，在其相应的PH-A曲线上总存在一段直线部分，通过选择一定PH变色范围和适当浓度的指示剂，就能使各指示剂PH-A曲线上的直线部分相互迭加成一条新的直线，从而加宽了混合指示剂的表现变色PH范围，依此原理，本论文以二种流动注射分析方法独立地完成了工艺流程中高浓定影液酸度的在线分析。并对这二种方法做了简单的对比。（一）工艺流程中高浓定影液酸度的在线分析方法研究（1）我们选择了内含0.08%溴甲酚紫，0.04%溴百里酚兰，0.02%甲酚红组成的混合指示剂的6%稀释液作为试剂，以C-41CX定影浓缩液作载流，用F2A-分光光度法完成了高浓度定影液酸度的在线测定，相对标准偏差在50.2%以内，采样频率为100次/h，分析周期很短（25秒），在5.5～8.0PH范围内，PH-A工作曲线具有很好的线性关系，相关系数0.9996，斜率即灵敏度达到：0.198A/PH。（二）工艺流程中高浓定影液酸遮掩在线分析方法研究（2）我们造反了0.005%的溴甲酚紫，0.009%的溴百里酚兰和0.025%的甲酚红作为混合酸碱指示剂，以蒸馏水作载流，通过选择最佳测定条件用流动注射-分光光度法（F2A-Spectrophotometry���在线测定了不宜用其它分析法测定的高浓溶液的酸度。该分析方法还可以推广到其它高浓溶液的酸度的在线测定。相对误差在±0.2%以内；分析周期为30秒；采样体积为60μL。在5.2～8.5PH范围内，混合指示剂的PH-A工作曲线具有良好的线性关系，相关系数达到0.9991，工作曲线斜率即是灵敏度达到0.376A/PH。

微生物法生成辅酶Q10的研究

本文根据我们实验室建立的发酵产物中辅酶Q10定性定量检测方法，筛选得到一株可以代谢产生较多辅酶Q10的野生菌株放射形土壤杆菌(Agrobacterium radiobacter No.50)。 为了提高放射形土壤杆菌的辅酶Q10的产量，本实验利用液体培养研究了单因素对菌株辅酶Q10产量的影响，并用正交法确定了最佳液态发酵条件。最佳发酵培养基是：葡萄糖20g,蔗糖40g, 硫酸铵10g,玉米浆30g, 酵母膏3g，K2HPO4 3g,MgSO4.7H2O 1g，蒸馏水1000mL,pH 7.0-7.2。最佳发酵条件是：转接斜面菌种到种子培养基, 转速220r/min、温度28。C培养24h后，转入发酵培养基(250mL三角拼装液量为50mL，pH 7.0), 接种量为10％，转速220r/min、温度28。C，培养120h。在此条件下，菌体湿重约为50g/L，辅酶Q10含量约为20mg/L。 本文以放射形土壤杆菌为出发菌株进行诱变育种，以期获得辅酶Q10高产菌。根据微生物育种原理、参照辅酶Q10的代谢调控机制，以野生型放射形土壤杆菌(Agrobacterium radiobacter No.50)为出发菌株，采用紫外线和亚硝基胍复合诱变技术，依次筛选得到菌体提取物M抗性菌ARM－7、烟草提取物T抗性菌株ARMT-26、Vk3抗性菌株ARMTV-25、链霉素抗性菌株ARMTVS-32，菌株ARMTVS-32产量达到了36.8mg/L，与原始出发菌株相比，产量提高了77％。 研究了茄尼醇、对羟基苯甲酸、橘子皮提取物D、胡萝卜提取物E、烟草提取物对ARMTVS-32合成辅酶Q10的影响，结果表明这些物质对菌体合成辅酶Q10有一定促进作用，添加0.2g/L茄尼醇时，辅酶Q10含量提高了17%，达到了40.7mg/L；添加1.2g/L橘子皮提取物D时，辅酶Q10含量提高了13.8%，达到了39.6mg/L；添加0.5g/L胡萝卜提取物E时，辅酶Q10含量提高了25.3% ，达到了43.6mg/L；添加8g/L烟草提取物时，辅酶Q10含量提高了12.6%，达到了39.2mg/L。 Production of Coenzyme- Q10 (CoQ10) by fermentation is considered as a process with broad prospects.Quantitative Analysis of CoQ10 in the culture of microbe by TLC—UV spectrophotometry was developed, by using this method we got the strain Agrobacterium radiobacter,which was isolated from forest soil of southwest of China. The effect of the single factor on CoQ10-production ability of the strain was examined by liquid cultured, and its best optimum cultivation conditions were established by orthogonal method. The results showed that the optimum fermentation conditions were as following: carbon sources glucose 20g/L,sucrose 40g/L; nitrongen sources (NH4)2SO4 10g/L,maize liquid 30g/L;yeast extract 3g; K2HPO4 3g/L,MgSO4.7H2O 1g/L; initial pH was 7 and volume of medium(medium volume vs flask volume) was 50mL/500mL, incubating for 120h on a rotary shaker at 220 rpm and 28℃.Under these conditions, the biomass and CoQ10 concentration reached 50g/L and 20mg/L respectively. According to the biosynthesis mechanism of CoQ10 and breeding theory, CoQ10 over-production strains were screened by UV--NTG. mutation using Agrobacterium radiobacter No.50 as parent strain. A microbe-juice resistant mutant ARMTVS-32, which also could resist tobacco-juice, VK3 and streptomycin, was screened out from an agar plate. The CoQ10 content of ARMTVS-32 reached 36.8mg/L, which was 77% higher than the initial strain. In addition, We discussed the effects of some organic substrates on the synthesis of CoQ10 in ARMTVS-32. The results showed that solanesol, orange juice D, carrot juice E and tobacco juice could promote the CoQ10 accumulation in the cells. The CoQ10 content of ARMTVS-32 reached 40.7mg/L when added 0.2g/L solanesol,it reached 39.6mg/L when added 1.2g/L orange juice D，it reached 43.6mg/L when added 0.5g/L carrot juice E. it reached 39.2mg/L when added 8g/L tobacco juice.

The preparation of 238U targets on 2mm Al foils

Preparation of 238U on 2μm Al foils by molecular plating technique is described. In order to obtain optimum conditions for deposition, several parameters influencing the quality of layers such as current density, distance between the anode and cathode and the deposition time were investigated. The target thickness was determined by spectrophotometry. The uniformity and morphology of the target surface were studied by means of scanning electron microscopy, energy dispersive X-ray spectrometry and Infrared spectra. The results show that uranium is deposited in its oxide or hydroxide form uniformly and adherently onto the foil.

Electrochemical polymerization and characterization of polypyrrole nanowires and nanotubules

Polypyrrole nanostructure arrays, including simultaneously large quantities of nanowires and small quantities of partially filled nanotubules have been electrochemically synthesized in home-made etched ion-track polycarbonate (PC) templates. Diameter of the prepared nanostructures varies from 45 to 320 nm with their lengths up to 30 microns. Morphological studies of these nanostructures were performed by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. While optical absorption properties were studied by ultraviolet-visible-near infrared spectrophotometry (UV-vis-NIR). It has been observed that the absorption maximum of polypyrrole shifts to the longer wavelength side as the diameter of these nanostructures (nanowires and nanotubules) increases. (C) 2010 Elsevier B.V. All rights reserved.

Preparation and characterization of PtSn/C anode electrocatalysts for direct ethanol fuel cell

Highly active PtSn/C catalyst was prepared by a polyol method. The catalyst was reduced in H-2/Ar atmosphere at 600 degreesC for 2 h in order to obtain different metallic phase. TEM images show uniform dispersion of spherical metal nanoparticles with average diameters of 1.8 and 3.9 nm for the as-prepared and treated catalysts, respectively. UV-vis spectrophotometry is employed to monitor the preparation process and the results indicate that Pt-Sn complex formed once the precursors of Pt and Sn were mixed together. The structure properties of the samples were characterized using X-ray diffraction. The results show that after reduction, the catalyst tends to form PtSn alloy. TPR experiment results show that Sn exists in multivalent state in the as-prepared sample while only zero-valence Sn was detected in the treated sample, while it could not be excluded that the multivalent tin existed in the treated sample. Cyclic voltammetry (CV) technique and single direct ethanol fuel cell (DEFC) tests indicate that the as-prepared catalyst possesses superior catalytic activity for ethanol oxidation to the treated sample. The results suggest that Pt and multivalent Sn are the active species for ethanol oxidation. (C) 2004 Elsevier B.V. All rights reserved.

Simultaneous determination of methylene blue and new methylene blue by slab optical waveguide spectroscopy and artificial neural networks

A slab optical waveguide (SOWG) has been used for study of adsorption of both methylene blue (MB) and new methylene blue (NMB) in liquid-solid interface. Adsorption characteristics of MB and NMB on both bare SOWG and silanized SOWG by octadecyltrichlorosilane (ODS) were compared. The simultaneous determinations of both MB and NMB were explored by flow injection SOWG spectrophotometric analysis and artificial neural networks (ANNs) for the first time. Concentrations of MB and NMB were estimated simultaneously with the ANNs. Results obtained with SOWG were compared with those got by conventional UV-visible spectrophotometry. (C) 2003 Elsevier Science B.V All rights reserved.

Effects of ultrahigh pressure extraction conditions on yields and antioxidant activity of ginsenoside from ginseng

Ultrahigh pressure technique was employed to extract ginsenosides from roots of ginseng (Panax ginseng C.A. Meyer). The optimal conditions for ultrahigh pressure extraction (UPE) of total ginsenosides were quantified by UV-vis spectrophotometry with the ginsenoside Re as standard, the signal ginsenosides were quantified by HPLC and ELSD with ginsenosides Re, Rg(1), Rb-1, Rc and Rb-2 as standards. Orthogonal design was applied to evaluate the effects of four independent factors (extraction pressure, extraction temperature, extraction time and ethanol concentration) on the yield and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of ginsenoside, which are based on microwave extraction (ME), ultrasound extraction (UE), soxhlet extraction (SE) and heat reflux extraction (HRE) method. The results showed that UPE method can produce ginsenoside with the highest yield and the best radical scavenging activity compared to other used ones. Scanning electron microscopic (SEM) images of the plant cells after ultrahigh pressure treatment was obtained to provide visual evidence of the disruption effect.

Isolation and extraction of total flavonoids from Epimedium Koreanum Nakai by supercritical fluid extraction

In the present paper is reported the method for the isolation and extraction of total flavonoids of Epimedium Koreanum Nakai by means of supercritical fluid extraction (SFE). By examining pressure, temperature. amounts of modifier and extraction time, the optimized condition of SFE is confirmed as 30 MPa and 60 degreesC. with 70% ethanol as the modifier. The samples were statically extracted for 30 min, followed by dynamic extraction for 120 min at a flow rate of 6 mL/min. The quantitative analysis of total flavonoids was performed by UV-Vis spectrophotometry. Compared with the conventional method, the SFE method is more efficient. more rapid and more friendly environmentally.

Analysis of flavonoids from leaves of Acanthopanax Senticosus Harms

Using electrospray tandem mass spectrometry (ESI-MSn), the flavonoids obtained from leaves in Acanthopanax Senticosus Harms were analyzed. The typical colorimetric method and the ultroviolet spectrophotometry were also utilized for the determination of the content of total flavonoids. The analytical results showed that there was quercetin as well as its derivatives in leaves of acanthopanax senticosus harms and their content was as high as 37.25%.