Interaction of Black Tea and Green Tea Polyphenols with Porcine Pancreatic α-amylase by Fluorescence Quenching

目的:本研究旨在用红茶和绿茶的茶多酚(TEA POlyPHEnOlS,TP)猝灭猪胰腺α-淀粉酶(POrCInE PAnCrEATICα-AMylASE,PPA)的蛋白质内源性荧光。方法:通过获得的荧光光谱,计算STErn-VOlMEr猝灭常数(kSV)、双分子猝灭常数(kQ)、表观静态猝灭常数(kAPP)、动态猝灭常数(kd)和静态猝灭常数(kS)。统计采用T检验,检验水平α=0.05。结果:结合和猝灭反应明显受到PPA结构的影响。通过STErn-VOlMEr荧光猝灭图显示的特征,证实TP与PPA之间发生的荧光猝灭为静态猝灭和动态猝灭。比较动、静态猝灭常数(kd与kS)之间的差异具有统计学意义(P<0.05);双分子猝灭常数(kQ)大于双分子扩散限制性猝灭常数(1x1010.M-1.S-1);表明红茶和绿茶的TP与PPA的反应是以形成基态复合物的静态猝灭为主。伴随红茶和绿茶溶液滴定的浓度增加,PPA荧光发射波长(λEM)发生红移,红茶猝灭时荧光发射波长由384nM红移至404nM,绿茶组则由384nM红移至402nM。红茶和绿茶TP的猝灭效果相同。结论:实验数据提示:TP与PPA的反应确引起了PPA的分子构象发生改变,TP与PPA的反应驱动力源自氢键结合、静电引力和疏水性反应。Objective:To study the binding of black tea and green tea polyphenols to porcine pancreatic α-amylase (PPA) by fluorescence quenching of protein intrinsic fluorescence.Methods:From the fluorescence spectra obtained,the Stern-Volmer (KSV),the bimolecular quenching (kq),the apparent static (Kapp),the dynamic quenching (KD) and the static quenching constants (KS) were calculated.The quenching data was analyzed with t-test (α=0.05).Results:The structure of PPA was revealed to significantly affect the binding/quenching process.From the characteristic feature of the Stern-Volmer plots,the dynamic and the static quenching were decided between tea polyphenols (TP) and PPA.There were significant differences between the dynamic quenching (KD) and the static quenching constants (KS) (P<0.05) ,and the value of the bimolecular quenching (kq) was larger than that of the bimolecular diffusion-controlled quenching constant (1×1010M-1·s-1),which indicated that the static quenching with the ground-state complex formation was the dominant reaction between TP (black tea and green tea) and PPA.In the titration with black tea and green tea solution,there was a small λem shift to higher wavelengths (a red shift from 384 to 404 nm for black tea and 384 to 402nm for green tea) with increasing TP concentration.There were the same effect of fluorescence quenching with the black tea and green tea TP.Conclusion:The data suggested that the reaction between TP and PPA did change molecular conformation of PPA and that the hydrogen bonding,electrostatic and hydrophobic interaction were equally important driving forces for TP-PPA association

Dynamic Investigation of Inhibitory Effects of Black Tea and Green Tea Polyphenols on Porcine Pancreatic α-amylase

目的:研究红茶和绿茶抑制剂对猪胰腺α-淀粉酶催化水解淀粉的抑制效果和特异性。方法:实验在25℃和PH6.9条件下进行。混合0.7 Ml不同浓度的淀粉和0.2 Ml红绿茶(7.5 g/l),添加0.1 MlPPA(0.04 g/l),进行5 MIn孵化反应。通过SMArTSPEC PluS SPECTrOPHOTOMETEr不间断540 nM波长下,测量PPA催化生成的麦芽糖的吸光度增加值。通过动力曲线的直线段斜率获得反应速度,动力学参数(VMAX和kS)由lInEWEAVEr-burk图求出,抑制类型通过统计学分析确定。结果:无抑制剂和红茶抑制剂的最大反应速度(VMAX)之间的差异具有统计学意义(P<0.05),无抑制剂和绿茶抑制剂的酶-底物解离常数(kS)之间的差异具有统计学意义(P<0.05)。红茶抑制剂解离常数(kI)值高于绿茶(P<0.05)。结论:红茶抑制为非竞争抑制型,绿茶抑制为竞争抑制型。红茶抑制剂既能与自由酶活化中心位点结合,也能与酶-底物上的位点结合,而绿茶抑制剂仅能与活化中心位点结合。Objective: To study the effectiveness and specificity of black tea and green tea inhibition of starch hydrolysis that was catalyzed by porcine pancreatic α-amylase(PPA).Methods: Kinetic experiments were carried out at 25℃and pH 6.9.Starch(0.7 mL) with different concentration and black tea and green tea(0.2 mL,7.5 mg/mL) were mixed together and the reaction was initiated by adding PPA(0.1 mL,0.04 mg/mL) to the incubation medium for 5 min.The increase of absorbance resulting from the PPA liberated maltose was measured continuously at 540nm using SmartSpec Plus Spectrophotometer.The initial velocity was determined from the slope of linear part of the kinetic curves.Kinetic parameters(Vmax,Ks) were calculated using Lineweaver-Burk plots.The type of inhibition was determined by statistical analysis.Results: There were significant differences between maximum velocity(Vmax) in the absence and presence of black tea inhibitor(P<0.05) and between the dissociation constants of enzyme-substrate(Ks) in the absence and presence of green tea inhibitor(P<0.05).The dissociation constant of black tea inhibitor(Ki) was much higher than that of green tea inhibitor.Conclusion: Acording to the statistical analysis,the black tea inhibition was belong to non-competitive inhibition type,and the green tea inhibition was belong to competitive inhibition type.The black tea inhibitor could bind either to the active site or to the other site of enzyme-substrate to give rise to enzyme-inhibitor and enzyme-substrate-inhibitor complexes,and the green tea inhibitor could only bind to the active site

The influence of toothbrushing effect on color and microstructure of light-curing resin composites after aging

目的:研究紫外光老化和水老化处理后的刷牙作用对光固化复合树脂的色度稳定性,表面显微结构和内部化学键的影响。方法:用紫外光老化和水老化方法处理光固化复合树脂样本,色度计测量复合树脂老化后刷牙作用造成的色差,用ESEM观察刷牙对处理后样本的表面显微结构,红外光谱仪分析复合树脂老化后刷牙作用对其化学键改变。配对t检验比较老化组间及刷牙组的复合树脂的色差。结果:紫外光老化与水老化后的复合树脂的色差均数之间的差异具有统计学意义(P0.05)。紫外光老化后刷牙导致复合树脂的基质出现凹陷,白色颗粒凸显,且内部化学键发生了明显改变,水老化刷牙后的改变较小。结论:与复合树脂水老化后的刷牙作用相比,紫外光老化后的刷牙作用对复合树脂的表面显微结构和内部化学键破坏作用大;刷牙作用对于老化后的复合树脂的颜色改变没有影响。Objective:The aim of this investigation was to examine the toothbrushing effect on the color stability, surface microstructure and inner chemical constitution of light-curing resin composites after an ultraviolet radiation aging and the water aging. Method:The specimens were treated with an ultraviolet radiation aging and the water aging, the color differences for toothbrushing effect after aging were measured by spectrophotometer,and the surface microstructure of resin composites were observed by ESEM,also the chemical bonds were investigated by a FTIR spectrophotometer. The color differences of resin composites after aging and toothbrushing were carried out with two-sided T-test for the groups. The level of significance was defined as α=0.05. Result:There were significant differences of the average value of color differences between an ultraviolet radiation aging and the water aging(P0.05). Some concaves emerged from the matrix of resin composites,and the wheat particles were exposed. The chemical bonds of the matrix were changed seriously after aging and toothbrushing, but there were litter changes of the matrix after water aging. Conclusion:There were more serious damage of tooothbrushing effect on the surface microstructure and inner chemical bonds of resin composites after an ultraviolet radiation aging then after the water aging. There were no influences of tooothbrushing effect on the color change of resin composites after aging

Evaluation of three transmission parameters of dental opal porcelains and the correlations among parameters

目的测量Ceramco、Shofu、Noritake和Vita等4个品牌22种不同颜色的乳光瓷样本的透明度、对比率和遮色效果3个透射参数,并比较其相关性,为正确选择及使用乳光瓷粉提供参考。方法在反射模式和不同背景下,采用分光光谱仪测量乳光瓷样本的L*、a*、b*值,计算色差、透明度参数(TP)和遮色效果(ME)。在400～750 nm光谱范围内测量样本的光反射率,计算对比率(CR)。TP、ME和CR等3个透射参数分别按品牌和颜色因素用完全随机设计的方差分析进行分析,组间比较用SNK-q检验(α=0.05);3个参数的相关性分析采用直线相关与回归分析和多元线性回归分析(α=0.05)。结果相同品牌不同颜色乳光瓷透射参数的均数总体不等或不全相等(P<0.05)。遮色效果与透明度参数、对比率与透明度参数、遮色效果与对比率的相关性都具有统计学意义(P<0.05)。透明度参数与其他参数的多元线性回归具有统计学意义(P<0.05),偏回归系数都有统计学意义(P<0.05),对比率对透明度参数的回归所起的作用最大。结论使用乳光瓷粉时,应根据其透射参数加以选择;对比率代表不透明度,反映乳光瓷的不透明特性,较遮色效果更具有代表性。Objective To measure the translucency parameter(TP),masking effect(ME),and contrast ratio(CR) of opal porcelain of Ceramco,Shofu,Noritake,and Vita,and to compare the correlations among the three transmission parameters,in order to provide reference for selecting opal porcelain correctly.Methods The color of specimens was measured according to CIE L*a*b* under different background and reflectance mode with a Color-Eye 7000A spectrophotometer.The color difference,TP,and ME value were calculated.Within 400-750 nm spectra,the ratio of light reflectance was measured,and CR was also calculated.The data was compared by ANOVA and SNK-q test(α=0.05).The correlation and multiple linear regression between TP,CR,and ME were analyzed(α=0.05).Results There were statistical difference with different shade of the same brands(P<0.05).The correlations between ME and TP,TP and CR,ME and CR were existed(P<0.05).TP was correlated not only with ME but also with CR based on multiple regression analysis(P<0.05).The partial correlation coefficients were statistically significant(P<0.05).CR was the main devotion to translucency parameter on multiple regressions.Conclusion It is recommended to select opal porcelains based on transmission parameters.CR value has an inner significance of opaque property of opal porcelain and can express opacity property of opal porcelain more appropriately than ME

Measurement and analysis of reflected fluorescence of opal porcelains

目的对Ceramco、Shofu、Noritake和Vita共22种不同颜色的乳光瓷样本的反射荧光进行测量和分析。方法采用分光光谱仪测量乳光瓷样本的L*、a*、b*值,计算反射模式下的荧光(色差)。绘制荧光光谱曲线。按品牌和颜色因素对反射荧光均值进行完全随机设计的方差分析,组间用SNK-q检验(α=0.05)。结果经方差分析,不同品牌乳光瓷粉的反射荧光均值总体不等或不全相等(P0.05)。结论4种品牌乳光瓷粉的平均反射荧光由大到小依此排列为:Noritake、Shofu、Ceramco、Vita。不同品牌乳光瓷的反射荧光光谱分布的差异主要表现在400nm以下,荧光峰值出现在390nm位置。Objective To measure and analyze the reflection fluorescence of four opal enamel porcelains.Methods Twienty two samples with differernt shades, which came from four opal enamel porcelains (Ceramco,Shofu,Noritake and Vita) were used. The CIE Lab of each sample was measured with Color- Eye 7000A spectrophotometer and the reflection fluorescence (color difference) of each sample was calculated and spectra curves were plotted. According to the product and the shade factors, the average values of the relfection fluorescence were compared by AVNOA, and the intergroups by SNK-q test (α=0.05).Results There existed statistical difference in reflection fluorescence among different prouducts (P0.05).Conclusion The sequence from high to low based on the average value of the reflection fluorescence was: Noritake, Shofu, Ceramco, Vita. The difference in the reflected fluorescence spectra distribution among different products lied below 400nm and the fluorescent peak appeared in 390nm

Fluorescence properties and color space of modifying porcelains

目的:探讨色参数差值与荧光发射量的相关性。方法:在Color-Eye7000A分光光谱仪上,用4种模式测定Vita Interno、Shofu Vintage&Unibond和Noritake Super Porcelain EX-3套装染色瓷粉的色参数,建立其CIE LAB色度空间坐标图;计算荧光发射量和反射光谱波长。用完全随机两因素方差分析和SNK-q检验(α=0.05),比较样本荧光发射量之间的差异,建立荧光发射量与色参数差之间的相关性分析(α=0.05)。结果:Vita与Shofu,Vita与Noritake的荧光发射量差别有统计学意义(P<0.05)。荧光发射量与色参数差值之间的相关性有统计学意义(P<0.05)。荧光光谱反射峰值均处于400nm附近。染色瓷粉的色度空间总体分布趋势为:Vita染色瓷粉的明亮度较高,且偏红-黄方向,Noritake偏绿-蓝方向,而Shofu居中。结论:测量模式对测定没有影响;Shofu和Noritake的荧光发射量比Vita大;染色瓷粉所发出的荧光偏紫色;3种套装染色瓷粉的CIE LAB色度空间有差别;荧光发射量与色参数差值总体上相关。Objective:To investigate the correlation between fluorescence emission and color difference (CIE△Eab). Methods:Color and spectral distribution in three kinds of modifying porcelains (Vita Interno, Shofu Vintage & Unibond, Noritake Super Porcelain EX-3) were measured on CIELAB color scale on Color-Eye 7000A spectrophotometer under four measuring modes. CIE△Eab were analyzed by two-way ANVOA and SNK-q test (α=0.05). Correlation analyses were also performed between CIE△Eab and the color parameters difference(α= 0.05). In addition, CIELAB color coordinate was established. Results:Fluorescence emission of Vita and Shofu, Vita and Noritake were significantly different(P<0.05). Fluorescence emission and the color parameters difference showed correlationship(P<0.05). The emission wavelength of fluorescence was about 400 nm. There were differences of three kinds of porcelain in color space. The total tendency of color space as follows: Vita owned higher value and was in red-yellow direction; the shade of Noritake was in blue-green direction, while color scale of Shofu was in the middle of the previous codes.Conclusion:Specular component included versus specular component excluded modes have no effects on fluorescence emission. The fluorescence values of Shofu and Noritake were larger than that of Vita. The shade of fluorescence was purple.福建省卫生厅科技联合攻关项目(编号:3502Z8021

The influence of accelerated aging on color and microstructure of light-curing composite resin

目的考察加速老化后光固化复合树脂的色度稳定性、表面显微结构和内部化学结构的改变及其相互之间的关系。方法用老化仪加速老化4种光固化复合树脂样本,测量老化24 h和96 h后的色差。用环境扫描电子显微镜和傅里叶变换红外光谱仪分别观察老化前后样本表面的显微结构和化学键的改变。用方差分析法分析老化时间与树脂色度间的交互影响(α=0.05)。结果老化时间与复合树脂类型之间具有交互作用(P<0.05),老化后复合树脂的色度改变具有统计学意义(P<0.05)。老化对复合树脂表面显微结构具有明显的影响,老化后基质出现凹陷,填料颗粒暴露,出现孔隙。老化使树脂内部化学键发生变化,基质中的化学键削弱和裂解,不饱和残余物再度聚合。结论随着老化时间的延长,复合树脂的色度变化加大;老化后混合型填料树脂的色度稳定性最好;老化使复合树脂内部化学键发生变化,色度发生改变。Objective The aim of this investigation was to examine the changes of the color stability,surface microstructure and chemical constitution of light-curing composite resin after accelerated aging,and the relations be-tween them.Methods Four light-curing composite resin were aged in an accelerated aging instrument.The color was measured by CIE L*a*b* with a spectrophotometer after treatment for 24 h and 96 h.And the color differences were calculated.Environmental scanning electron microscopy(ESEM) and Fourier transform infrared spectroscopy(FTIR) spectrometer were used to examine the microstructure and chemical composition of the specimens before and after accelerated aging.The color differences were analyzed statistically by repeated-measures two-way analysis of variance and t-test after aging for 24 h and 96 h.The level of significance was defined as α=0.05.Results The materials demonstrated statistically significant differences in color after aging between the 24 h and 96 h(P<0.05).There were significant influences on the microstructure and the chemical composition after aging.The matrix appeared some concaves and pores,the filler particles exposed after aging.The energy of chemical bonds were weaken or broken under the aging,and the unsaturated polymer reacted again.Conclusion The color differences of the composite resin increase with the aging time and irradiation dose.The hybrid filled composites have the best color stability

Eof Mode Analysis of Surface Pattern of the Kuroshio in the Luzon Strait

应用ArgOS表层漂流浮标资料所指示的浮标轨迹图以及基于卫星高度计资料和三维水动力模型海面高度场数据的经验正交函数(EOf)模态分析,探讨了黑潮在吕宋海峡形变的时空分布特征.结果表明:吕宋海峡黑潮的形态呈现明显的季节变化,其中跨隙形态为其最基本的形态;秋冬两季,部分黑潮水会以流套和分支的形式入侵南海,流套最西可延伸至118°E;春夏季节则几乎不出现流套或者分支的结构,相反会有一部分南海水汇入黑潮主干.模型数据模态分析结果还再现了冬季黑潮水沿着南海北部陆坡向西入侵的形态.The temporal and spatial variations of Kuroshio patterns in the Luzon Strait were studied with the use of the Argos surface drifter data,as well as empirical orthogonal function(Eof) mode analysis of the satellite altimeter data and the sea surface height data resulting from a three-dimensional hydrodynamic model.Both trajectories of Argos surface drifting buoys and Eof mode analysis results reveal that the Kuroshio patterns in the Luzon Strait have significant seasonal variations.Kuroshio leaps across the Luzon Strait all around the year.During fall and winter,Kuroshio also loops and branches into the South China Sea(SCS) through the Luzon Strait,the loop can intrude as far as 118°E,but it seldom happens in the other two seasons when SCS water joins into the Kuroshio in reverse.Model data Eof mode analysis results also indicate that one branch of Kuroshio intrudes into SCS along the continental slope of northern SCS in winter

Monitoring the Biofilm Formation of Human Saliva in the Gold Surface by Quartz Crystal Microbalance with Dissipation

目的:采用消散因子石英晶体微天平(QCM-d)原位、实时和动态测量全唾液、腮腺唾液和颌下腺/舌下腺唾液在Au石英晶体芯片表面形成生物膜的过程。方法:收集刺激性的上述3种唾液,QCM-d监测唾液蛋白吸附于Au石英晶体芯片表面所造成的频率改变和消散因子的变化,及形成生物膜的质量、厚度、剪切弹性模量和剪切粘度。数据用单因素方差分析和lSd检验进行两两比较(A=0.05)。结果:全唾液、腮腺唾液和颌下腺/舌下腺唾液蛋白质吸附达饱和状态时的频率改变,生物膜厚度和质量为SMSlS>W S>PS(PSMSlS和W S(PWS>PS(PSMSLS and WS(P<0.05).Conclusion: The characteristics of kinetics adsorption and formation of biofilm difference among three saliva were caused by their different components.QCM-D was an effective tool to study biofilm

Measurement and analysis of opalescence parameters of opal porcelains

目的:测量Ceramco、Shofu、Noritake和Vita乳光瓷样本的乳光参数(OP)、光谱透射率、反射率和晶粒的大小,考察乳光产生的原因。方法:采用分光光谱仪测量乳光瓷样本的乳光参数和平均光谱透射率与反射率(%),绘制乳光光谱曲线。对数据进行完全随机设计的方差分析,组间用SNK-q检验(α=0.05)。乳光参数与色差、色参数差之间采用直线相关与回归分析(α=0.05)。用粉末X射线衍射仪,进行样本的物相和晶粒分析。结果:4种乳光瓷的OP均值、光谱差值以及同品牌不同颜色的OP均值总体不等或不全相等(P<0.05)。被检样本均含有白榴石、方石英晶相和玻璃相,仅NoritakeLT1含有水合硅酸盐晶相;被检瓷样本的晶粒大小在58.4~73.6nm范围内。结论:乳光效果可采用OP值和光谱反射率和透射率差值表达,但二者之间存在差异。OP值的大小与黄蓝轴色参数(Δb*)改变密切相关;乳光瓷的白榴石晶粒大小与乳光效果没有直接关系。Objective:To measure the opalescence parameter(OP) transmittance and reflectance values, and the size of internal particles of opal porcelain (Ceramco, Shofu, Noritake, and Vita) in order to examine the mechanisms that cause phenomenon of opalescence. Methods:OP, average reflectance and transmittance values (%) of specimens were measured by spectrophotometer. Opalescence spectra curve were plotted. Data were compared by AVNOA and SNK-q test (α=0.05). The correlation among E*ab, OP and color parameters were analyzed (α=0.05). X-ray diffraction was also performed. Results:There were significant differences on the average OP among the four different brands or the same brands with different color and difference in the spectral distribution(P<0.05). X-ray diffraction patterns of examined porcelains were strongly matched with the leucite crystal. All porcelains also contained an amorphous glass component and cristobalite, while Noritake LT1 had silicate hydrate. The range of the size of examined specimen was 58.4~73.6 nm. Conclusion:There are differences between two methods to describe the opalescence by the OP and difference in the spectral distribution. The opalescence values are intensively correlated to the difference in yellow-blue color coordinate. There are no direct relationship between the size of leucite crystal and opal effect in examined opal porcelain