大孔吸附树脂对桃叶珊瑚苷分离效果的研究

目的:优选分离车前草全草中桃叶珊瑚苷的大孔树脂.方法:将车前草粗提液置大孔树脂中吸附,并以水、50%和70%乙醇分别洗脱,用紫外分光光度法测定各洗脱液中桃叶珊瑚苷含量.结果:D100、D101、D140、D141、D19和D301R 6种型号大孔树脂效果差异较大.结论:D141和D301R型大孔树脂能较好的富集桃叶珊瑚苷.     

D101吸附树脂再生工艺实验研究二:再生液流量、用量及温度对再生效果的影响

目的研究D101吸附树脂的再生活化工艺.方法采用正交试验法,以树脂比吸附量作为参考指标,考察酸、碱两种再生液的流量(A)、用量(B)、温度(C)三个因素对再生效果的影响.结果两种再生液的流量、用量、温度经优化后提示为A1B3C3.结论 D101树脂再生活化时,当再生液的酸、碱、乙醇浓度选择0.05mol·L-1NaOH的75%乙醇溶液和0.1mol·L-1HCl的90%乙醇溶液时,其的流量、用量、温度应为1.0SV、5.0BV,30℃.     

顶空气相色谱法检测百乐眠胶囊中树脂残留物

建立气相色谱法检测百乐眠胶囊中树脂残留物的方法.采用气相色谱法对百乐眠胶囊中苯、甲苯、二甲苯、正己烷、苯乙烯、1,4-二乙苯的残留量进行检测,气相色谱条件为:色谱柱HP-5,载气为高纯氮气,柱前压为10Psi,气化室温度200℃,柱温60℃(5min),以30℃*min-1的速率升至90℃(3.5min),再以30℃*min-1的速率升至140℃(4min),最后以30℃*min-1的速率升至190℃(3min),检测器为FID,温度为220℃.正己烷在1.815～29.060μg*ml-1,苯在0.0128～0.1966μg*ml-1内,甲苯在0.685～11.125μg*ml-1内,二甲苯在1.698～27.170μg*ml-1内,苯乙烯在1.695～27.125μg*ml-1内,1,4-二乙苯在1.699～27.140μg*ml-1内均有良好的线性关系,相关系数分别为0.9996、0.9991、0.9996、0.9998、0.9966、0.9980.本法简便、快速、准确度高,适于测定百乐眠胶囊中树脂残留物,可作为百乐眠胶囊的质量监控方法.     

苦丁茶中熊果酸的分离纯化研究

 目的研究苦丁茶(Ilex kudingcha C.J.Tseng)中熊果酸的分离纯化,建立分离纯化工艺条件,以利于苦丁茶资源的开发利用。方法以熊果酸浸出率为考核指标,采用正交实验法考察诸因素对浸出率的影响。乙醇提取液经沉淀富集和大孔树脂柱色谱纯化得到熊果酸,采用HPLC分析检测。结果优化的提取条件为:在85℃水浴中,以体积分数90％乙醇水溶液为提取溶剂。固液比为1:14,提取2次,每次提取2.5h,熊果酸的浸出率可达到1.44％。D₈树脂分离富集的最优条件:样品溶液熊果酸浓度1～2 mg·mL^-1,样品溶液pH=6.0～7.0,吸附1h,洗脱剂pH=11.0,依次用水、4倍体积30％乙醇、4倍体积90％乙醇以2～3mL·min^-1的流速洗脱,收集90％乙醇洗脱液,熊果酸回收率为97.82％,纯度为95.0％。结论 该工艺产品纯度高,收率高,可实现工业化。     

D301树脂吸附丹参有效成分的研究

目的 :考察利用大孔树脂D301,富集丹参水提取液中有效成分丹参素及原儿茶醛 ,去除杂质 ,降低出膏率 ,提高膏中有效成分含量。方法 :以丹参素 ,原儿茶醛为指标 ,HPLC检测分离前后有效成分的含量变化。结果 :D301树脂能够有效的吸附丹参素和原儿茶醛。结论 :采用D301树脂可以作为改进分离纯化工艺 ,去除杂质 ,提高粗提物中有效成分含量。     

D140大孔树脂分离纯化淫羊藿黄酮的研究

目的:研究大孔树脂提取淫羊藿黄酮的工艺.方法:以淫羊藿苷含量为指标,用不同浓度的乙醇进行洗脱,对D140大孔树脂吸附剂提取淫羊藿总黄酮的工艺进行了筛选,并对树脂的使用次数进行了考察.结果:当乙醇浓度为80％时可以洗脱完全,大孔树脂使用次数10次以上.结论:提取淫羊藿总黄酮的含量大于60％,而且工艺简便,树脂再生容易,提取方法可取.     

大孔吸附树脂对白藜芦醇苷静态吸附性能的研究

目的 研究白藜芦醇苷在大孔吸附树脂上的静态吸附。方法 考察了吸附温度、吸附液pH值、洗脱液浓度对静态吸附性能的影响。结果与结纶 吸附温度增加,吸附液pH提高,都可以导致降低白藜芦醇苷在树脂上的吸附性能。     

Influence of various irradiation processes on the mechanical properties and polymerisation kinetics of bulk-fill resin based composites

ObjectivesTo assess the effect of irradiation time and distance of the light tip on the micro-mechanical properties and polymerisation kinetics of two bulk-fill resin-based composites at simulated clinically relevant filling depth.MethodsMicro-mechanical properties (Vickers hardness (HV), depth of cure (DOC) and indentation modulus (E)) and polymerisation kinetics (real-time increase of degree of cure (DC)) of two bulk-fill resin-based composites (Tetric EvoCeram^® Bulk Fill, Ivoclar Vivadent and x-tra base, Voco) were assessed at varying depth (0.1–6 mm in 100 μm steps for E and HV and 0.1, 2, 4 and 6 mm for DC), irradiation time (10, 20 or 40 s, Elipar Freelight2) and distances from the light tip (0 and 7 mm). Curing unit's irradiance was monitored in 1 mm steps at distances up to 10 mm away from the light tip on a laboratory-grade spectrometer.ResultsMultivariate analysis (α = 0.05), Student's t-test and Pearson correlation analysis were considered. The influence of material on the measured mechanical properties was significant (η² = 0.080 for E and 0.256 for HV), while the parameters irradiation time, distance from the light tip and depth emphasise a stronger influence on Tetric EvoCeram^® Bulk Fill. The polymerisation kinetics could be described by an exponential sum function, distinguishing between the gel and the glass phase. The above mentioned parameters strongly influenced the start of polymerisation (gel phase), and were of less importance for the glass phase.ConclusionsBoth materials enable at least 4 mm thick increments to be cured in one step under clinically relevant curing conditions.Clinical significanceThe susceptibility to variation in irradiance was material dependent, thus properties measured under clinically simulated curing conditions might vary to a different extent from those measured under ideal curing conditions.     

Large‐scale bone mineral histomorphometry – report of a simplified technique

Karantzoulis V, Liapi C & Papaggelopoulos P
(2012) Histopathology
Large‐scale bone mineral histomorphometry – report of a simplified technique Aims: The aim of this study was the development of a simplified technique for bone mineral histomorphology on large undecalcified bone samples. Established techniques, such as undecalcified bone thin sectioning, ultrathin grinding, surface‐stained block grinding and micro‐computerized tomography (CT), are expensive, time‐consuming and put very high demands on equipment, safety standards, personnel and laboratory facilities. Methods and results: The method is based on the surface‐stained block‐grinding principle; however, its novelty lies in the selection of user‐friendly, safe and low‐cost materials, equipment and digitization techniques. We describe in detail the relevant steps, as well as many practical tips for their successful implementation: accurate bone cutting in thin sections with a customized arrangement on a commercial bandsaw, defatting with sodium hypochlorite, embedding in epoxy resin blocks at room temperature, silicon carbide paper grinding, von Kossa staining, flatbed scanner digitization and image processing. Conclusion: We believe that the proposed methodology could contribute to the expansion of the study of bone tissue, as it enables the rapid examination of bone specimens on a large scale with minimal laboratory requirements and consumables costs.     

Bonding performance and interfacial characteristics of short fiber‐reinforced resin composite in comparison with other composite restoratives

The purpose of this study was to investigate the shear bond strength (SBS) and surface free‐energy (SFE) of short fiber‐reinforced resin composite (SFRC), using different adhesive systems, in comparison with other composite restoratives. The resin composites used were everX Posterior (EP), Clearfil AP‐X (CA), and Filtek Supreme Ultra Universal Restorative (FS). The adhesive systems used were Scotchbond Multi‐Purpose (SM), Clearfil SE Bond (CS), and G‐Premio Bond (GB). Resin composite was bonded to dentin, and SBS was determined after 24 h of storage in distilled water and after 10,000 thermal cycles (TCs). The SFEs of the resin composites and the adhesives were determined by measuring the contact angles of three test liquids. The SFE values and SFE characteristics were not influenced by the type of resin composite, but were influenced by the type of adhesive system. The results of this study suggest that the bonding performance and interfacial characteristics of SFRC are the same as for other composite restoratives, but that these parameters are affected by the type of adhesive system. The bonding performance of SFRC was enhanced by thermal cycling in a manner similar to that for other composite restoratives.