We studied the effect of two independent variables, the pectin/calcium chloride weight ratio and the overall matrix weight in HPMC/pectin/calcium matrix tablet, on the release of indomethacin. A two-factor 5-level cen...We studied the effect of two independent variables, the pectin/calcium chloride weight ratio and the overall matrix weight in HPMC/pectin/calcium matrix tablet, on the release of indomethacin. A two-factor 5-level central composite experimental design was employed. Responses of the Peppas correlation parameters n and K and the 10% release time （T0.1） were optimized by response surface methodology. Significant effect of the independent variables on the biphasic release parameters, n and K, was observed. N, K and T0.1 were well fitted with the second-order quadratic equations rather than linear equations. Moreover, the mathematic fitting and the response surfaces showed significant cross-interaction between the pectin/calcium chloride ratio and the overall matrix weight. The optimal formulation with larger n, longer T0.1 and smaller K consisted of medium pectin/calcium chloride ratio around 1.0 and medium matrix weight around 200 mg. Validation studies on the optimal formulations showed good predictability of the n, K and T0.1 values with biases within the range of-7.33% and 6.26%. Our results support that central composite design can be used to optimize drug release from HPMC/pectin/calcium matrix tablet with high predictability.展开更多
目的研究光固化树脂表面处理剂是否对牙齿美白后反色效应有所影响。方法将24颗完整的离体磨牙或前磨牙于美白前以分光测色仪SCM-104记录CIE(L*,a*,b*)值作为基准值。在各样本颊侧涂35%浓度的过氧化氢,波长(810±10)nm二极体激光照...目的研究光固化树脂表面处理剂是否对牙齿美白后反色效应有所影响。方法将24颗完整的离体磨牙或前磨牙于美白前以分光测色仪SCM-104记录CIE(L*,a*,b*)值作为基准值。在各样本颊侧涂35%浓度的过氧化氢,波长(810±10)nm二极体激光照射完成漂白。以分光比色仪记录美白后釉质表面的ΔE。将24颗样本随机均分为L+B组(表面涂布Adper Single Bond 2 Adhesive光固化树脂表面处理剂)与L组(不涂布Adper Single Bond 2 Adhesive光固化树脂表面处理剂),n=12。记录涂布表面处理剂后的釉质表面色差ΔE1,所有样本保存在蒸馏水中1 h避免脱水,1 h后记录釉质表面色差ΔE2。将L+B组与L组随机各自均分为两小组,其中(L+B)W与LW组浸泡于37℃蒸馏水及(L+B)T与LT组浸泡于37℃茶水中,n=6,完成老化测试。记录各小组各时间点的颜色变化CIE(L1*,a1*,b1*)。对涂布处理剂前后和老化试验后的实验数据进行单因素方差分析和样本均数的t检验。扫描电子显微镜观察各处理样本4周时间点的牙釉质表面微观结构。结果ΔE(8.46±3.7)与ΔE1(8.32±3.97)及ΔE2(7.82±2.74)之间没有显著差异(P>0.05)。老化实验LW与(L+B)W组按各个时间点测定色差值之间均没有统计学差异(P>0.05),LT与(L+B)T组以各时间点比较各组间色差的变化,结果差异均有统计学意义(P<0.05)。扫描电镜显示样本美白处理后的釉质表面存在破坏,空洞。而涂布表面处理剂后的样本釉质可变得光滑。老化实验蒸馏水组样本均只见少量块状染色层、孔洞。茶水(L+B)T组样本表光滑,有部分裂痕,片状染色层颜色分解不明显。而LT组样本表面是有孔洞的粗糙面及清晰的茶水染色层。结论涂布Adper Single Bond 2 Adhesive光固化树脂表面处理剂能够使激光美白后的牙釉质表面变得平滑,降低色层的黏附,从而起到牙齿美白后降低反色效应的作用。展开更多
Negative skin friction (NSF) is one of the important problems when designing a pile foundation. However, the influence of loading sequence on the dragload and downdrag for pile foundation is seldom studied. In this pa...Negative skin friction (NSF) is one of the important problems when designing a pile foundation. However, the influence of loading sequence on the dragload and downdrag for pile foundation is seldom studied. In this paper, a three-dimensional numerical model was established using FLAC3D. Compared with the results of model test, the established model could be used to study the NSF of pile foundation. The influencing factors were discussed including the length-diameter ratio of pile and the loading sequence of pile head load and surcharge. A case history was analyzed using FLAC3D. The calculated results are in good agreement with the measured results. It is concluded that the dragload and downdrag are remarkably influenced by the loading sequence of pile head load and surcharge. The dragload and downdrag reach the maximum values under the condition of surcharge after pile head load.展开更多
The purpose of this paper is to examine the relationships of e-service quality dimensions with overall internet banking service quality, and its effect on customer satisfaction in the USA banking industry. The propose...The purpose of this paper is to examine the relationships of e-service quality dimensions with overall internet banking service quality, and its effect on customer satisfaction in the USA banking industry. The proposed instrument dimensions are identified based on a questionnaire survey conducted in the US. Based on an extensive review of literature, this paper proposed eight dimensions for measuring overall internet banking service quality and its subsequent effect on customer satisfaction. Also, this research uses American internet banking users as survey targets for its empirical studies. The results show significant relationships among the e-service quality dimensions （efficiency, fulfillment, system availability, privacy, assurance/trust, site aesthetics, responsiveness, and contact）, overall internet banking service quality, and customer satisfaction. Little attention has been given in the literature to understanding of the e-service quality dimensions that influence overall internet banking service quality and the specific outcome of customer satisfaction. This paper empirically examines the relationships among the eight e-service quality dimensions, overall internet banking service quality, and customer satisfaction. The findings are important to enable bank managers to have a better understanding of the key e-service quality dimensions of internet banking that affect customer satisfaction. The primary limitations of this study are the scope and size of its sample.展开更多
Estimation of soil organic carbon （SOC） pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time. Although development of the U.S. Soil Survey Geographic Da...Estimation of soil organic carbon （SOC） pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time. Although development of the U.S. Soil Survey Geographic Database （SSURGO）, currently the most detailed level with a map scale ranging from 1：12 000 to 1：63 360, has involved substantial government funds and coordinated network efforts, very few studies have utilized it for soil carbon assessment at the large landscape scale. The objectives of this study were to 1） compare estimates in soil organic matter among SSURGO, the State Soil Geographic Database （STATSGO）, and referenced field measurements at the soil map unit; 2） examine the influence of missing data on SOC estimation by SSURGO and STATSGO; 3） quantify spatial differences in SOC estimation between SSURGO and STATSCO, specifically for the state of Louisiana; and 4） assess scale effects on soil organic carbon density （SOCD） estimates from a soil map unit to a watershed and a river basin scale. SOC was estimated using soil attributes of SSURGO and STATSGO including soil organic matter （SOM） content, soil layer depth, and bulk density. Paired t-test, correlation, and regression analyses were performed to investigate various relations of SOC and SOM among the datasets. There were positive relations of SOC estimates between SSURGO and STATSGO at the soil map unit （R2 = 0.56, n = 86, t = 1.65, P = 0.102; depth： 30 cm）. However, the SOC estimated by STATSGO were 9%, 33% and 36~ lower for the upper 30-cm, the upper l-m, and the maximal depth （up to 2.75 m） soils, respectively, than those from SSURGO. The difference tended to increase as the spatial scale changes from the soil map unit to the watershed and river basin scales. Compared with the referenced field measurements, the estimates in SOM by SSURGO showed a closer match than those of STATSCO, indicating that the former was more accurate than the latter in SOC estimation, both in spatial and temporal resolutions. Further applications of SSURGO in SOC estimation for the entire United States could improve the accuracy of soil carbon accounting in regional and national carbon balances.展开更多
基金Shanghai Municipal Committee of Sciencc and Tcchnology (Grant No.024319114).
文摘We studied the effect of two independent variables, the pectin/calcium chloride weight ratio and the overall matrix weight in HPMC/pectin/calcium matrix tablet, on the release of indomethacin. A two-factor 5-level central composite experimental design was employed. Responses of the Peppas correlation parameters n and K and the 10% release time （T0.1） were optimized by response surface methodology. Significant effect of the independent variables on the biphasic release parameters, n and K, was observed. N, K and T0.1 were well fitted with the second-order quadratic equations rather than linear equations. Moreover, the mathematic fitting and the response surfaces showed significant cross-interaction between the pectin/calcium chloride ratio and the overall matrix weight. The optimal formulation with larger n, longer T0.1 and smaller K consisted of medium pectin/calcium chloride ratio around 1.0 and medium matrix weight around 200 mg. Validation studies on the optimal formulations showed good predictability of the n, K and T0.1 values with biases within the range of-7.33% and 6.26%. Our results support that central composite design can be used to optimize drug release from HPMC/pectin/calcium matrix tablet with high predictability.
文摘目的研究光固化树脂表面处理剂是否对牙齿美白后反色效应有所影响。方法将24颗完整的离体磨牙或前磨牙于美白前以分光测色仪SCM-104记录CIE(L*,a*,b*)值作为基准值。在各样本颊侧涂35%浓度的过氧化氢,波长(810±10)nm二极体激光照射完成漂白。以分光比色仪记录美白后釉质表面的ΔE。将24颗样本随机均分为L+B组(表面涂布Adper Single Bond 2 Adhesive光固化树脂表面处理剂)与L组(不涂布Adper Single Bond 2 Adhesive光固化树脂表面处理剂),n=12。记录涂布表面处理剂后的釉质表面色差ΔE1,所有样本保存在蒸馏水中1 h避免脱水,1 h后记录釉质表面色差ΔE2。将L+B组与L组随机各自均分为两小组,其中(L+B)W与LW组浸泡于37℃蒸馏水及(L+B)T与LT组浸泡于37℃茶水中,n=6,完成老化测试。记录各小组各时间点的颜色变化CIE(L1*,a1*,b1*)。对涂布处理剂前后和老化试验后的实验数据进行单因素方差分析和样本均数的t检验。扫描电子显微镜观察各处理样本4周时间点的牙釉质表面微观结构。结果ΔE(8.46±3.7)与ΔE1(8.32±3.97)及ΔE2(7.82±2.74)之间没有显著差异(P>0.05)。老化实验LW与(L+B)W组按各个时间点测定色差值之间均没有统计学差异(P>0.05),LT与(L+B)T组以各时间点比较各组间色差的变化,结果差异均有统计学意义(P<0.05)。扫描电镜显示样本美白处理后的釉质表面存在破坏,空洞。而涂布表面处理剂后的样本釉质可变得光滑。老化实验蒸馏水组样本均只见少量块状染色层、孔洞。茶水(L+B)T组样本表光滑,有部分裂痕,片状染色层颜色分解不明显。而LT组样本表面是有孔洞的粗糙面及清晰的茶水染色层。结论涂布Adper Single Bond 2 Adhesive光固化树脂表面处理剂能够使激光美白后的牙釉质表面变得平滑,降低色层的黏附,从而起到牙齿美白后降低反色效应的作用。
基金Supported by National Natural Science Foundation of China (No.50679015)China Postdoctoral Science Foundation (No.20090461062)
文摘Negative skin friction (NSF) is one of the important problems when designing a pile foundation. However, the influence of loading sequence on the dragload and downdrag for pile foundation is seldom studied. In this paper, a three-dimensional numerical model was established using FLAC3D. Compared with the results of model test, the established model could be used to study the NSF of pile foundation. The influencing factors were discussed including the length-diameter ratio of pile and the loading sequence of pile head load and surcharge. A case history was analyzed using FLAC3D. The calculated results are in good agreement with the measured results. It is concluded that the dragload and downdrag are remarkably influenced by the loading sequence of pile head load and surcharge. The dragload and downdrag reach the maximum values under the condition of surcharge after pile head load.
文摘The purpose of this paper is to examine the relationships of e-service quality dimensions with overall internet banking service quality, and its effect on customer satisfaction in the USA banking industry. The proposed instrument dimensions are identified based on a questionnaire survey conducted in the US. Based on an extensive review of literature, this paper proposed eight dimensions for measuring overall internet banking service quality and its subsequent effect on customer satisfaction. Also, this research uses American internet banking users as survey targets for its empirical studies. The results show significant relationships among the e-service quality dimensions （efficiency, fulfillment, system availability, privacy, assurance/trust, site aesthetics, responsiveness, and contact）, overall internet banking service quality, and customer satisfaction. Little attention has been given in the literature to understanding of the e-service quality dimensions that influence overall internet banking service quality and the specific outcome of customer satisfaction. This paper empirically examines the relationships among the eight e-service quality dimensions, overall internet banking service quality, and customer satisfaction. The findings are important to enable bank managers to have a better understanding of the key e-service quality dimensions of internet banking that affect customer satisfaction. The primary limitations of this study are the scope and size of its sample.
基金Supported by the U.S. Louisiana Board of Regents (No. LEQSF (2004-2007)-RD-A-04)
文摘Estimation of soil organic carbon （SOC） pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time. Although development of the U.S. Soil Survey Geographic Database （SSURGO）, currently the most detailed level with a map scale ranging from 1：12 000 to 1：63 360, has involved substantial government funds and coordinated network efforts, very few studies have utilized it for soil carbon assessment at the large landscape scale. The objectives of this study were to 1） compare estimates in soil organic matter among SSURGO, the State Soil Geographic Database （STATSGO）, and referenced field measurements at the soil map unit; 2） examine the influence of missing data on SOC estimation by SSURGO and STATSGO; 3） quantify spatial differences in SOC estimation between SSURGO and STATSCO, specifically for the state of Louisiana; and 4） assess scale effects on soil organic carbon density （SOCD） estimates from a soil map unit to a watershed and a river basin scale. SOC was estimated using soil attributes of SSURGO and STATSGO including soil organic matter （SOM） content, soil layer depth, and bulk density. Paired t-test, correlation, and regression analyses were performed to investigate various relations of SOC and SOM among the datasets. There were positive relations of SOC estimates between SSURGO and STATSGO at the soil map unit （R2 = 0.56, n = 86, t = 1.65, P = 0.102; depth： 30 cm）. However, the SOC estimated by STATSGO were 9%, 33% and 36~ lower for the upper 30-cm, the upper l-m, and the maximal depth （up to 2.75 m） soils, respectively, than those from SSURGO. The difference tended to increase as the spatial scale changes from the soil map unit to the watershed and river basin scales. Compared with the referenced field measurements, the estimates in SOM by SSURGO showed a closer match than those of STATSCO, indicating that the former was more accurate than the latter in SOC estimation, both in spatial and temporal resolutions. Further applications of SSURGO in SOC estimation for the entire United States could improve the accuracy of soil carbon accounting in regional and national carbon balances.
