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1.
A novel fluorimetric method for determination of laccase activity in organic solvents is proposed, based on the oxidation
ofo-phenylenediamine (1,2-diaminobenzene, OPDA) catalyzed by laccase yielding 2,3-diaminophenazine. The optimal conditions for
laccase in organic media areT=55°C, pH=6.5, 1.0×10−2mol/L OPDA, 1.25 mL ethanol, 1.25 mL 1,4-dioxane and 1.25 mL acetone. The linear range of the method proposed in ethanol,
1,4-dioxane and acetone media were 0.44–19.33, 0.11–20.85, 0.38–21.05 U with the detection limit of 0.088, 0.022, 0.076 U,
respectively. The proposed method has been applied to the analysis of laccase activity of real samples with more accurate
and sensitive than that of the previous method reported.
Supported by the National Natural Science Foundation of China and the Special Founds of State Education Committee for Doctorate
Research
Huang Zuyun: born in 1963, Ph.D 相似文献
2.
A novel spectrofluorimetric method for the determination of L-ascorbic acid is proposed. It is based on the inhibition of
L-ascorbic acid on the formation of 2,3-diaminophenazine, which is an oxidation product ofo-phenylenediamine catalyzed by laccase. The fluorescence (at λcx/λcm=464 nm /530 nnm) was enhanced strongly in the presence of organic media. The mechanism ofo-phenylenediamine oxidation reaction catalyzed by laccase in the presence of L-ascorbic acid is discussed. L-ascorbic acid
is determined in the ethanol, 1,4-dioxane and acetone over the linear range of 4.0×10−7≈1.2×10−4 mol/L, 4.0×10−7≈8.0×10−5 mol/L and 4.0×10−7≈1.0×10−4 mol/L with a detection limit of 1.20×10−5 mol/L, 1.19×10−5 mol/L and 1.24×10−8 mol/L, respectively. The method has been successfully applied to the simple and rapid determination of L-ascorbic acid in
pharmaceuticals and milk powder.
Supported by National Natural Science Foundation of China and the Special Funds of State Education Committe for Doctorate
Research
Huang Zuyun: born in Aug. 1963. Ph.D 相似文献
3.
Yongfen Qi Dingfang Bu Jun Yang Zhaokang Zhang Yanrong Shi Yongzheng Pang Chaoshu Tang 《科学通报(英文版)》2002,47(17):1457-1461
The aim of this study was to observe the effects of adrenomedullin (ADM) on endothelin (ET) production induced by urotensin Ⅱ (UⅡ) in rat vascular smooth muscle cells (VSMCs). Cultured VSMCs which were incubated with UⅡ (10-8 mol/L) and with various concentrations of ADM were used to measure the VSMCs 3H-TdR incorpora- tion, the activity of extracellular signal-regulated kinase (ERK), the amount of ET mRNA and ET production in VSMCs. In this work we found that incubation with UⅡ(10-8 mol/L) increased obviously the amount of ET mRNA in VSMCs and ET production in medium, however, coincubation with ADM (10-10—10-8 mol/L) and UⅡ(10-8 mol/L) reduced the amount of ET mRNA by 15%, 24% and 45% (P< 0.01) respectively, compared with UⅡ alone. The content of ET in medium was 14.13, 11.38 and 11.00 pg/mL. ADM alone (10-8 mol/L) had no effect on ET production in VSMCs. UⅡ (10-8 mol/L) promoted the 3H-TdR incorpo- ration and activity of ERK in VSMCs. ADM inhibited VSMCs 3H-TdR incorporation and activation of ERK in a concentration-dependent manner. Compared with UⅡ group, after coincubation with ADM (10-10—10-8 mol/L) and UⅡ (10-8 mol/L) the VSMCs 3H-TdR incorporation was decreased by 7% (P > 0.05), 32% (P < 0.05) and 41% (P < 0.01), respectively, and the activity of ERK was decreased by 24% (P > 0.05), 32% (P < 0.05) and 36% (P < 0.05), re- spectively, in a concentration-dependent manner. The results show that in cultured VSMCs ADM inhibits ET mRNA expression, ET production and proliferation stimulated by UⅡ, and that inhibitory effect of ADM on UⅡ bioaction could be mediated through inhibiting MAPK pathway. 相似文献
4.
This investigation aimed at improving the performance of Taylor's dispersion analysis for the fast and accurate measurement of diffusion coefficient of a minute solute in various solvents. The investigation was carried out on a capillary electrophoresis instrument by monitoring the UV absorption peak of a solute pulse and calculating the diffusion coefficient by peak efficiency. With L-phenylalanine as a main testing solute, some key factors were afterward disclosed including especially the capillary size, carrier flow velocity, injection volume and capillary conditioning. Peak tailing, large volume of sample injection and slow migration were found to underestimate the diffusion coefficient while very fast migration and high sample concentration caused overestimation. At a moderate flow velocity of 0.1―1 cm/s with a capillary of 72.44 μm I.D.×60 cm (50 cm effective) maintained at 25℃, the diffusion coefficient of aqueous L-phenylalanine was determined, giving a value of 7.02×10-6 cm2/s with error<2% and relative standard deviation<0.2% (n=3). The method was shown to be applicable to the measurement of various samples such as aqueous phenylalanine, acetone, phenol, toluene and benzene, and nonaqueous benzene (in ethanol or 1-butanol). 相似文献
5.
CHEN Lihua~ ZHANG Yongkang~ YIN Hong~ LIU Liuzhan~ YANG Zhaoxia~ SHEN Hanxi~ . College of Chemistry Chemical Engineering Jishou University Jishou Hunan China . College of Chemistry Nankai University Tianjin China 《武汉大学学报:自然科学英文版》2006,11(3):704-708
0 IntroductionMaalnadria siusb atr ompajicosr .he aAltrthe pmrisoibnlienmi (n qtihneghtraoopsiucs,QHS,Fig.1) is a sesquiterpene endoperoxide isola-ted fromArtemisia annuaL., an ancient Chineseherbal medicine usedfor treatment of fever and ma-laria.Studies of the structure and activity relation-ship have shownthat endoperoxide groupis essentialfor anti malarial activity of QHS and absence of thismoiety lead to completely loss in activity of thedrug. Many techniques have been developed to de… 相似文献
6.
CUIJianzhong KimSung-Hoon 《科学通报(英文版)》2004,49(8):797-802
Several organic electroluminescent (EL) compounds, 2,2‘-(1,4-phenylenedivinylene)bis-3,3-dimethyl-indolenine (1), 2,2‘-(1,4-phenylenedivinylene)bis-benzoxazole (2), 2,2‘-(1,4-phenylenedivinylene)bis-benzothiazole (3), 4,4‘-(1,4-phenylenedivinylene)bis-quinoline (4), 2,2‘-(1,4-phenylene divinylene)bis-quinoline (5), 2,2‘-(1,4-phenylenedivinylene)bis-1,3,3-trimethyl-indolenine dichlo ride (6), 2,2‘-(1,4-phenylene-divinylene)bis-1-hydro-3,3-dimethyl-indolenine dichloride (7), 2,2‘-(1,4-phenylenedivinylene)bis-8-acetoxy-quinoline (8), 2,2‘-(1,4-phenylenedivinylene)bis-8-hydroxyquinoline (9) and metal complexes of 9, Al(PHQ) (10) and Zn(PHQ) (11), have been synthesized and characterized. The crystal structure of 6 was determined. Light emitting properties of the prepared compounds have been investigated. 1 produces an orange-yellow emission (λmax=575nm). The cation, 6, gives a red emission (λmax=607nm), which is shifted 32 nm to the red compared to 1.8 produces a yellow emission (λmax=567nm). The metal complex 10 gives a red emission (λmax=610nm), which is a red shift of 43 nm compared to 8. The change in structure in the prepared compound caused a change in the electron distribution in the compounds, which induces a large wavelength shift of the emitted-light. Thermal analysis showed that the decomposition temperatures of the metal complexes (10, 11) were higher than those for the smaller organic molecular compounds (1-9). Therefore, metal complexes (10, 11) can be used as EL materials over a larger temperature range. 相似文献
7.
Pan Zu-ting Yu Jun-ping College of Chemistry Molecular Sciences Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2004,9(3):353-358
0 IntroductionTriamcinoloneAcetonide,9 fluoro 11β,2 1 dihydroxy 16α,17[(1 methylethylidene)bis (oxy) ] pregn 1,4 diene 3,2 0 dione,Mris 4 34.4 8(abr.TA ) .Itbelongstoaclassofadrenalcortexhormonedrug ,whosefunctionsareaffectionofsugarmetabolism ,anti inflammationandresistancehypersusceptibilityetc.TAcanbesuitabletorheumatoidarthritisanddermatosissuchashypersusceptibilityandneuropathicdermatitis .ThefunctionsofTAisstrongerandlongerthantriamcinolone[1 ,2 ] .ThecommonmethodsofdetectingTAm… 相似文献
8.
The conditions of color reaction of Aluminium(III) with a new organic reagent 2,3,7-trihydroxy-9-[2,4-dihydroxy)phenylazo]
phenylfluorone (ARPF) in the presence of cetyltrimethyammonium bromide (CTMAB) were studied. It was found that Aluminium(III)
reacts with ARPF and CTMAB in pH 6.5 HAc-NaAc buffer solution to form a 1∶2 red complex with maximum absorption at 562 nm.
The molar absorptivity is 1.10×105 L·mol−1·cm−1. Beer’s law is obeyed in the range of 0–5.5 μg Al(III) per 25 mL. The method has been applied to determination of Aluminium
in the limestone with satisfactory results.
To whom Correspondence should be addressed
Foundation item: Supported by Special Funds of State Education Committee for Doctorate Research
Biography: Huang Ying-ping (1963-), male, Ph.D Candidate. 相似文献
9.
A study on the distribution characteristics of soil organic carbon (SOC) in the alpine meadow in the Eastern Qinghai-Tibet
Plateau has been carried out. The results indicate that the content of soil organic carbon (C
SOC) in the topsoil of terrace meadow (TM) ((67.16 ± 1.02) g·kg−1) is more than that in the soil of upland meadow (UM) ((63.42 ± 0.65) g·kg−1), while the C
SOC in upland shrubland (US) ((67.49 ± 0.83) g·kg−1) is the most abundant in the scoreh stage (September). From May to September, the C
SOC in the topsoil of UM and US tends to descend, but that of TM tends to ascend. As for the distribution of the C
SOC and the density of SOC in the soil in the three sample areas, the data show that the deeper the soil, the lesser the content
and density of SOC. The C
SOC in US is higher than that in TM and UM; the C
SOC in UM is the lowest at 0–10 cm soil depth. The density of SOC in US is always the lowest among UM, TM, and US at 0–40 cm
depth, which shows that the storage of carbon in UM is more than that in US in the same range; the carbon pool capacity in
UM is higher than that in US in the same range.
Biography: ZHANG Wei (1979–), male, Lecturer, research direction: ecology of environment. 相似文献
10.
An α-amylase encoding gene was amplified by polymerase chain reaction fromSaccharomycopsis fibuligera and inserted into a shuttle vector YEp352, together with the yeast phosphoglycerate kinase 1 promoter and α-factor signal
gene. The recombinant expression plasmid pLA8α was transformed into an industrial strain ofSaccharomyces cerevisiae Sc-11. The activity of the α-amylase produced by the transformant Sc-11-pLA8α was 6.3 U/mL and the starch utilization rate
in YPS medium was 42%. The purified amylase was analyzed by SDS-PAGE, showing a molecular weight of 55×103 protein band. Furthermore, the residual sugar, ethanol and some volatile compounds in the fermented worts under simulating
brewing conditions were determined by chromatographic analyses. The fermentation characteristics of Sc-11-pLA8α were similar
to that of Sc-11 and only minor changes in the concentration of flavor compounds could be observed.
Foundation item: Supported by the National Tenth Five-Year Hi-Technique Project (2001BA708B05-04).
Biography: LIU Zeng-ran (1964-), fenale, Ph. D., research, direction: food and biotechnology. 相似文献
11.
The influences of cupric ion concentration (5–35 g/L), current density (500–2000 A/m2), circulation rate of the electrolyte solution (15–120 mL/min), and temperature (25–60°C) on the physical and chemical properties
of copper powders obtained in electrolysis cells were investigated. Two industrial processes, electrorefining (ER) cells with
a synthetic electrolyte and electrowinning (EW) cells with an original solution of copper mineral leaching, were utilized
to produce copper powders. Finally, the statistical full factorial method of design of experiments (DOE) was employed to investigate
the interaction or the main effects of processes. The results show that increasing the copper concentration and temperature
can increase the grain size, apparent density, and electrical energy consumption. On the other hand, increasing the current
density and circulation rate of the electrolyte can decrease them. This production process is optimized via DOE to control the interactive and main effects to produce copper powders with favorable properties. 相似文献
12.
Li Li-qing Chen Dong-hua College of Chemistry Life Sciences South Central University for Nationalities Wuhan Hubei China 《武汉大学学报:自然科学英文版》2004,9(2):239-246
0 IntroductionThetechnologyofthermalanalysishasbeenwidelyusedinthestudyofthermalbehaviorandthermalcharacterofsolidstatereaction ,theprimaryintentionofthermalanalysiskineticsistoestablishseparatevaluesofapparentactivationenergyE ,themostprobablemechanism g(α)andthepre exponentialfactorA ,meanwhilethedeterminationofg(α)hasgraduallybeenthefocusofthisfield .Inthisfield ,therearemostlygeneralkineticsmethodsused presently ,suchasCoats Redfern’s[1 ] integralmethod ,Achar’s[2 \〗differentialmet… 相似文献
13.
Sensitive Determination of DNA by RLS Enhancement of Metal Ions 总被引:1,自引:0,他引:1
Huang Jian-ping Chen Fang Ai Xin-ping He Zhi-ke . College of Chemistry Molecular Sciences Wuhan University Wuhan Hubei China . Department of Environmental Engineering Hubei Agricultural College Jingzhou Hubei China 《武汉大学学报:自然科学英文版》2004,9(2):234-238
0 IntroductionThequantitativeanalysisofnucleicacids,especiallythemi cro determinationofnucleicacids,isbecomingmoreandmoreimportantinmanybiologicalstudies.Recently ,apromisingspectraltechnique ,whichwasbasedonthemeasurementofen hancedresonancelightscattering (RLS) [1 ,2 ] ,hasgivenrisetostronginterestbyanalystsandbiochemistsfornucleicacidsandproteinassay[3 9] .Uptonow ,manykindscompoundshavebeenfoundRLSenhancementwhilebindingtoDNA ,andallthesecompoundsarecharacterizedofpositivechargewhicha… 相似文献
14.
A new fluorescent reagent, 7-(8-hydroxy-3, 6-disulfonaphthylazo)-8-hydroxyquinoline-5-sulfonic acid (HDNHQ) for the determination
of magnesium has been developed. It reacted with magnesium to form a 1∶1 fluorescent complex withλ
ex/λ
em immediately at room temperature in ammonia-ammonium chloride buffer (pH 10.7). A linear relationship was obtained in the
magnesium concentration range of 0–160 ng·mL−1 with the detection limit of 0.04 ng·mL−1. The proposed method was simple, rapid and sensitive. It has been successfully applied to the determination of trace magnesium
in blood serum with recoveries of 103.75% and 98.16%, respectively.
Foundation item: Supported by the Zi-Qiang Foundation of Wuhan University
Biography: Zhang Xian (1975-), female, Ph. D candidant, research direction: organic reagent synthesis and analysis. 相似文献
15.
A large number of adventitious buds were induced fromin vitro cultured young inflorescences of haploids of rice. Having been subcultured on solidified subculture media at 26°C for 7 days,
the adventitious buds were loaded into 1.8 mL plastic cryotubes with cryoprotectant and kept on ice for 45–60 min. After cooled
at a rate of 1.0°C/min down to −40°C, the samples, were kept in liquid nitrogen. The adventitious buds which have been cryopreserved
for about 30 days were thawed rapidly in 38–40°C water and then plated on solidified MS medium containing 3% sucrose, 0.5
mg/L NAA and 2.0 mg/L kinetin. After plated, 23%–32% of adventitious buds resumed growth and 15%–22% regenerated plantlets.
The results of this work indicated that the adventitious buds derived fromin vitro cultured young inflorescences is a critical factor for the success and subculturing adventitious buds on MS medium containing
3% sucrose and 4% sorbitol or 20% potato extract is essential to the procedure. The effective cryoprotectant is 10% DMSO (dimethyl
sulfoximide)+0.5 mol/L sorbitol.
Supported by the Natural Science Foundation of Hubei Province
Zhang Zhihong: born in 1963, Lecturer 相似文献
16.
SHI Bo’an~ ZENG Danyun~ JI Xinghu~ XI Juan~ AI Xinping~ HE Zhike~ . College of Chemistry Molecular Sciences Wuhan University Wuhan Hubei China . Department of Chemistry Chemical Engineering Hubei Institute for Nationalities Enshi Hubei China 《武汉大学学报:自然科学英文版》2006,11(3):672-676
0 IntroductionThbiep ycroidmipnlee)xru ctahteinoinu mof(Ⅱ r)u t(he Rniuu(mbip,y m)3ai2n +ly) atrnids- t(r2is -,(21’ -,10-phenanthroline)ruthenium(Ⅱ) (Ru(phen)32 +) ,is a kindof sensitive analytical reagent for electrogenerated chemilumi-nescence(ECL) and chemiluminescence(CL) ,on which a par-ticular review has been presented[1]. The earliest publicationon the synthesis of Ru(bipy)32 +appeared in 1936[2], andduringthefollowing30 years ,theinvestigations relatedtothissubstance were only in… 相似文献
17.
A highly sensitive and specific microplate chemiluminescence enzyme immunoassay (CLEIA) was developed for the quantitative evaluation of carbohydrate antigen 72-4 (CA72-4) in human serum, using luminol-H2O2 catalyzed by horseradish peroxidase (HRP) as the chemiluminescence system. The simple and quick determination was accomplished through a sandwich reaction mode. Several physicochemical parameters of the immunoreaction, including incubation conditions, antibody coating conditions, dilution ratio of anti-CA72-4-HRP conjugate, and chemiluminescence reaction time, were studied and optimized. The proposed method exhibited a linear range of 0-200 U/mL with correlation coefficient and detection limit of 0.9995 and 0.18 U/mL, respectively. The inter-assay and intra-assay coefficients of variation (CV) were both less than 10%. The average recovery of two clinical sera with low and high concentration CA72-4 was 99.3% and 98.7%, respectively. Normal tumor markers, including AFP, CEA, CA24-2, CA19-9 and CA15-3, did not cross-react with each other. The method's stability was evaluated by assessing its analytical performance after storing the immunoreagents at 4℃ and 37℃ for 7 days. Little difference was found, indicating satisfactory stability of the method. The present method has been successfully applied to the detection of CA72-4 human serum, and showed a good correlation with the commercially available ELISA kit (r^2=0.9383). This method showed great potential in the fabrication of diagnostic kit for CA72-4, and could be well used in diagnosis of cancer in clinical practice. 相似文献
18.
ZHENG Qi~ CAO Qihua~ LIU Zhihong~ CAI Ruxiu~ . College of Chemistry Environmental Engineering Jianghan University Wuhan Hubei China . College of Chemistry Molecular Sciences Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2006,11(3):677-681
0 IntroductionSltougdiiceasl csoynstceermnsin gharveeac btieveen o txhyeg ei nm psopretcaienst ( oRbjOecSt) iinn bbiioo--medicine and analytical chemistry in recent years[1-4]. Manyi mportant life phenomena and diseases are relatedtotheinter-mediates of ROS[5-7].ROS have beeni mplicated as ani mpor-tant causative factor in cell damage,including apoptosis andnecrosis . Their proposed actions comprise lipid peroxidation,DNAdamage,the mitochondrial respiratory chain destructionand protein mo… 相似文献
19.
A new method is proposed for the preconcentration of vanadium(V) with crosslinked chitosan (CCTS) and determination by graphite
furnace atomic absorption spectrometry (GFAAS). The adsorption rate of vanadium(V) by CCTS was 97% at pH 4.0, and vanadium(V)
was eluted from crosslinked chitosan with 2 mL 2.0 mol·L−1 chlorhydric acid and determined by GFAAS. The detection limit (3σ,n=7) for vanadium (V) was 4.8×10−12g and the relative standard deviation (R.S.D) at concentration level of 2.6 μg·L−1 is less than 3.6%. The method shows a good selectivity and high sensity, and it was applied to determination of vanadium(V)
in oyster and water samples. The analytic recoveries are (97±5)%.
Biography: Wu Wei (1975-), female, Master candidate, research direction: environmental & analytical chemistry. 相似文献
20.
The single phase LiNiVO4 has been successfully synthesized by adopting a new mild liquid route with oxalic acid as both complexant and precipitant, and this method is named the CPG method. The products were obtained by sintering the dry gel precursor which was prepared by the CPG method at 200—850℃ for 2—10 h in air. The products were tested by XRD, XPS, ESR and TGA-DTA, and the results indicate that the single phase LiNiVO4 could be obtained at 450℃ for 2—3 h in air and LiNiVO4 was still steady at 850℃ for 10 h. The valence analyses show that in LiNiVO4 the valence of lithium is +1, both nickel and vanadium have the mixed valence, namely +2, +3 for nickel and +4, +5 for vanadium respectively. The LiNiVO4 can be expressed as LiNi3+xNi2+1-xV4+xV5+1-xO4 (0≤x<1). The pyrolysis mechanism of the dry gel is also discussed. 相似文献