花芪灵丹丸质控标准研究

目的建立花芪灵丹丸的质量控制标准。方法采用显微鉴别法鉴别花芪灵丹丸中茯苓、牡丹皮、肉桂;采用薄层色谱法鉴别花芪灵丹丸中黄芪、红花、延胡索;采用高效液相色谱法定量检测花芪灵丹丸中丹参酮ⅡA的含量,建立质量控制标准。结果显微鉴别和薄层色谱鉴别效果好,专属性强;含量测定丹参酮ⅡA在0.01592μg~0.796μg范围内,进样量与峰面积积分值呈良好的线性关系,平均加样回收率为101.5%(RSD值3.8%)。结论花芪灵丹丸的质控方法操作简便、结果准确、重现性好,而且能够对花芪灵丹丸进行定性和定量质控,符合中药制剂的质控要求,可用于花芪灵丹丸质量的控制。     

Voltammetric lability of multiligand complexes: the case of ML2

The voltammetric lability of a complex system, where a metal ion M and a ligand L form the species ML and ML₂, is examined. Together with the rigorous numerical simulation of the problem, two limiting cases are analysed for the overall process ML₂ → M: (i) the most common case for aqueous complexes, where ML → M is the kinetically limiting step and (ii) the case where ML₂ → ML is limiting. In both cases, analytical expressions for the lability criteria are provided which show good agreement with the results obtained from the rigorous numerical simulation of the problem.     

Electrochemical aspects of the formation of Bi2Te3 thin film via the route of ECALE

A Bi₂Te₃ VA–VIA group compound thin film was prepared via the route of electrochemical atomic layer epitaxy in this paper. The dependence of thin film formation on the electrochemical conditions (such as deposition potential control, supporting electrolyte and substrate) was studied, and the formation process of Bi₂Te₃ film was determined. The results show that Bi upd on Pt occurs at more negative potential in a HNO₃ supporting electrolyte than in a HClO₄ supporting electrolyte, and the Te upd peak moves to a more negative potential in HClO₄ supporting electrolyte solution than that in HNO₃ solution; Both Te and Bi upd on an Ag substrate occur at more negative potentials than that on a Pt substrate. In order to reach steady state deposition, a potential adjustment is necessary for the first 30 or more cycles of each component. After deposition of this initial ‘buffer layer’, the potentials can be kept constant for the remaining cycles. The effect of the slope of the shift of potential used to deposit the first 30 atomic layers of Bi and Te on the deposit has also been investigated. The deposit exhibits a two phase mixture of excess elemental Bi and Bi₂Te₃ compound when the slope is larger than ?4 mV/p (p indicates per cycle); a single-phase Bi₂Te₃ compound was obtained at a slope of ?6 mV/p, and Bi₄Te₃ compound also appears in the deposit along with Bi₂Te₃ when the slope is decreased to a more negative value of ?10 mV/p.     

Hall effect measurements on CdTe layers electrodeposited from acidic aqueous electrolyte

The electrical properties of CdTe layers electrodeposited from an acidic sulfate aqueous electrolyte were examined by resistivity and Hall effect measurements. It was revealed that the resistivity, conduction type, and carrier density of the as-deposited CdTe layers could be controlled by the deposition potential. The resistivity varied in the range from 2 × 10⁶ to 2 × 10⁸ Ω cm. The CdTe layers deposited at potentials slightly positive to the Cd²⁺/Cd equilibrium potential (?0.37 V vs. SHE?E??0.30 V) had n-type conductions, while those deposited at more positive potentials (?0.15 V ?E??0.05 V) were p-type. The carrier densities of the CdTe layers were on the order of 10¹⁰–10¹¹ cm^?3. As the deposition potential became more positive, the electron density decreased, and conversely, the hole density increased. The electron mobilities for the n-type CdTe layers were in the range 7–40 cm² V^?1 s^?1, while the hole mobility was about 1 cm² V^?1 s^?1.     

Atomic analysis and knoop hardness measurement of the cavity floor prepared by Er,Cr:YSGG laser irradiation in vitro

In the present study, the compositional changes and knoop hardness of the cavity floor prepared by Er,Cr:YSGG laser irradiation was compared with that of the conventional bur cavity. Fifteen laser and 15 bur cavities were cross-sectioned, and subjected to atomic analysis by SEM-EDX and knoop hardness test. Statistical analyses were performed using the Mann-Whitney U-test; a value of P < 0.01 was considered significant. Surface characteristics of the prepared cavities were also investigated by light microscopy and scanning electron microscopy (SEM). The results showed that the quantities of Ca (Ca weight %) and P (P weight %) were increased significantly in the laser cavity floor but no significant differences were found between the Ca/P ratio and knoop hardness number of laser and bur cavities. The SEM observation revealed that the lased cavity surface was irregular and there was also the absence of a smear layer; the orifice of dentinal tubules was exposed. Er,Cr:YSGG laser device is considered as one of the most effective and safe devices for cavity preparation because of its many advantages. This includes easy delivery system, minimal thermal damage to the surrounding tissues, minimal thermal-induced changes of dental hard tissue compositions, and favourable surface characteristic.     

Improving the effect of NaOCl pretreatment on bonding to caries-affected dentin using self-etch adhesives

Objective

To evaluate the effect of sodium hypochlorite pretreatment on adhesion to normal and caries-affected dentin using self-etch adhesives.

Methods

Forty extracted human molars with coronal carious lesions were used in this experiment. The occlusal dentin surfaces including the caries-affected dentin in each group were treated as follows: group 1, rinsed with water; group 2, treated with 6% NaOCl for 15 s; group 3, treated with 6% NaOCl for 30 s; group 4, application with Accel for 30 s after NaOCl-30 s pretreatment. After rinsing with water and air-drying, the treated dentin surfaces were applied with self-etch systems (Bond Force and Clearfil Protect Bond) according to the manufacturers’ instructions, and built-up with resin composite. After 37 °C water storage for 24 h, the bonded normal or caries-affected dentin areas were isolated to create an hourglass configuration with a cross-sectional area of approximately 1 mm². The specimens were subjected to tensile stress at a cross-head speed of 1.0 mm/min.

Results

NaOCl-15 s pretreatment significantly improved the μTBS of both self-etch adhesives to caries-affected dentin, while the 30 s pretreatment did not affect them. For normal dentin, NaOCl-30 s pretreatment significantly reduced the μTBS of both self-etch adhesives although the 15 s pretreatment did not alter them. Furthermore, the application of Accel with a reducing effect increased the μTBS to normal and caries-affected dentin treated with NaOCl for 30 s.

Conclusions

The effects of NaOCl pretreatment on bonding of both self-etch adhesives were dependent upon type of dentin (normal and caries-affected dentin) and the treatment time.