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目的评价含生物活性玻璃成分的脱敏剂与氟保护漆联合应用对牙本质小管的堵塞效果及治疗牙本质过敏症(dentin hypersensitivity,DH)的临床疗效。方法选择2013年6月到2014年6月到中国医科大学口腔医学院干诊科就诊的59例DH患者的120颗患牙,随机分为A组(41颗)、B组(39颗)、C组(40颗),分别使用氟保护漆、奥敏清及氟保护漆与奥敏清联合涂布敏感处,应用视觉模拟评分(visual analogue scale,VAS)法评价其疗效。另选择因正畸需要拔除的完整无龋坏前磨牙20颗,制备成敏感模型后随机分为a、b、c、d四组,每组5颗,a、b、c三组处理方法同上述A、B、C组,d组为空白对照组,用蒸馏水进行处理,扫描电镜观察各组牙本质小管的堵塞情况。结果 A、B、C三组的VAS评分值在处理即刻均明显下降,且随时间推移均有增高趋势;有效率比较,A、C两组在1个月时差异有统计学意义(P<0.05),其他各组间在各时点差异均无统计学意义(P>0.05);各组内比较,A组即刻与1个月时差异具有统计学意义(P<0.05)。扫描电镜观察a、b、c三组牙本质小管均有不同程度堵塞,其中以联合应用组效果最佳。结论含生物活性玻璃成分的脱敏剂与氟保护漆联合应用堵塞牙本质小管的效果最佳,且具有较好的临床效果。     

Polymerization shrinkage kinetics and degree of conversion of commercial and experimental resin modified glass ionomer luting cements (RMGICs)

ObjectivesTetrahydrofurfuryl-methacrylate (THFM) and hydroxypropyl-methacrylate (HPM) were used to partially or fully replace HEMA in experimental RMGICs. The experimental materials were compared with home and commercial products in terms of degree of conversion, polymerization shrinkage and exotherm.MethodsTwo commercial RMGICs used were Fuji-Plus (FP, GC, Japan) and RelyX-Luting (RX, 3M-ESPE, USA). Two additional in-house liquids were prepared based on the commercial materials liquids. Eight experimental liquid compositions (F1, F2, F3 and F4 based on Fuji-Plus; R1, R2, R3 and R4 based on RelyX-Luting) were prepared replacing 100% HEMA with HPM in F1 and R1 or 70%/30% HPM/THFM in F2 and R2. 50% HEMA was replaced with THFM in F3 and R3 compared to 30% in F4 and R4. All liquids were mixed with the corresponding commercial powder. Degree of conversion was determined using Fourier-transform infrared spectroscopy (FT-IR). Polymerization shrinkage and exotherm were measured using the bonded-disk method.ResultsCompositions containing HPM (F1 and R1) showed lower degree of conversion compared to experimental compositions containing THFM, home and commercial materials (p < 0.0001). FP-commercial showed significantly higher polymerization shrinkage and exotherm compared to all other materials in both groups (p < 0.0001). FP-commercial showed higher degree of polymerization shrinkage and exotherm at 5 min compared to all materials due to the incorporation of an additional cross-linker (glycerol-dimethacrylate). In general, compositions containing THFM, presented polymerization shrinkage and degree of conversion values similar to their corresponding commercial products.SignificanceTHFM monomer showed promising results and could be potentially useful in the development of new RMGICs with improved properties.     

Using machine learning for improving knowledge on antibacterial effect of bioactive glass

The aim of this work was to find relationships between critical bioactive glass characteristics and their antibacterial behaviour using an artificial intelligence tool. A large dataset including ingredients and process variables of the bioactive glasses production, bacterial characteristics and microbiological experimental conditions was generated from literature and analyzed by neurofuzzy logic technology. Our findings allow an explanation on the variability in antibacterial behaviour found by different authors and to obtain general conclusions about critical parameters of bioactive glasses to be considered in order to achieve activity against some of the most common skin and implant surgery pathogens.     

Alkaline Oesophageal Reflux-An Artefact Due to Oxygen Corrosion of Antimony pH Electrodes

Antimony electrodes are widely used for gastro-oesophageal pH monitoring. They are also sensitive to oxygen, however, especially at low Po₂ levels, which are known to shift recorded values in the alkaline direction. This study, which compares antimony and glass electrodes for oesophageal pH monitoring in six adults, shows that values recorded by antimony electrodes are 2.1 ± 0.8 pH units (mean ± SD) higher than by glass electrodes (p < 0.001; n = 7642). A further 52 patients with suspected gastro-oesophageal reflux were investigated by 24-h pH monitoring by means of antimony electrodes. In these patients the oesophageal pH was higher than 8.0 for 7% of the time (range, 0–60%). The alkaline periods recorded with antimony electrodes were all protracted in time, smoothly increasing from a neutral pH, and did not correspond to a sudden increase in pH, which would be expected if alkaline reflux had occurred. It is concluded that high pH values obtained by antimony electrodes are due to the oxygen sensitivity of the electrodes. The diagnosis of alkaline reflux seems to be valid only when pH monitoring is performed with glass electrodes or when values obtained with antimony electrodes are adjusted for the influence of the oxygen tension in the oesophagus.     

Effect of AlF3 on the Density and Elastic Properties of Zinc Tellurite Glass Systems

This paper presents the results of the physical and elastic properties of the ternary zinc oxyfluoro tellurite glass system. Systematic series of glasses (AlF₃)_x(ZnO)_y(TeO₂)_z with x = 0–19, y = 0–20 and z = 80, 85, 90 mol% were synthesized by the conventional rapid melt quenching technique. The composition dependence of the physical, mainly density and molar volume, and elastic properties is discussed in term of the AlF₃ modifiers addition that are expected to produce quite substantial changes in their physical properties. The absence of any crystalline peaks in the X-ray diffraction (XRD) patterns of the present glass samples indicates the amorphous nature. The addition of AlF₃ lowered the values of the densities in ternary oxyfluorotellurite glass systems. The longitudinal and transverse ultrasonic waves propagated in each glass sample were measured using a MBS8020 ultrasonic data acquisition system. All the velocity data were taken at 5 MHz frequency and room temperature. The longitudinal modulus (L), shear modulus (G), Young’s modulus (E), bulk modulus (K) and Poisson’s ratio (σ) are obtained from both velocities data and their respective density. Experimental data shows the density and elastic moduli of each AlF₃-ZnO-TeO₂ series are found strongly depend upon the glass composition. The addition of AlF₃ modifiers into the zinc tellurite causes substantial changes in their density, molar volume as well as their elastic properties.     

On Structure and Properties of Amorphous Materials

Mechanical, optical, magnetic and electronic properties of amorphous materials hold great promise towards current and emergent technologies. We distinguish at least four categories of amorphous (glassy) materials: (i) metallic; (ii) thin films; (iii) organic and inorganic thermoplastics; and (iv) amorphous permanent networks. Some fundamental questions about the atomic arrangements remain unresolved. This paper focuses on the models of atomic arrangements in amorphous materials. The earliest ideas of Bernal on the structure of liquids were followed by experiments and computer models for the packing of spheres. Modern approach is to carry out computer simulations with prediction that can be tested by experiments. A geometrical concept of an ideal amorphous solid is presented as a novel contribution to the understanding of atomic arrangements in amorphous solids.     

Structural and elemental characterization of glass and ceramic particles for bone surgery

ObjectiveClinically used bioceramics have been characterized previously with different kinds of methods and comparison of results have proven to be difficult due to varieties of the material properties of interest. Therefore, in this study we compared clinically commonly used bioceramics of hydroxyapatite and carbonate apatite, two bioactive glasses 45S5 and S53P4, and alumina with respect of properties which according to the present knowledge are significant for bone biology.MethodsPhysicochemical properties of the materials were characterized by various methods. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) was used to analyze the material vibrational features. X-ray Power Diffraction (XRD) was used to characterize the material crystal structure and scanning electron microscopy-energy-dispersive x-ray analysis (SEM-EDXA) was used to evaluate the morphology and size of the materials and to calculate their oxide content. The dissolution behavior of the materials, ion release and pH changes in Tris buffer in a continuous flow-through reaction for 24-hours were determined. The change of the surface of the bioactive glasses by interfacial reaction during the Tris immersion was examined and the thickness of the surface reaction layer of the materials was studied.ResultsSEM examination showed that the particle morphology of BG 45S5, BG S53P4 and alumina particle’s surface was smooth. The surface of HAP was porous, but also CAP showed some surface porosity. An increase in the pH of the immersion solution was observed especially for BG 45S5 and BG S53P4. HAP, CAP and alumina caused only a minor increase in pH. BGs 45S5 and S53P4 showed a rapid initial release of sodium and calcium ions, followed by the release of silicon species. Minor release of sodium ions was registered for HAP, CAP and alumina. Calcium ion release was low but constant over the experimental time while only a minor initial dissolution was measured for HAP.SignificanceThe in vitro study showed differences in the materials’ properties, which are considered to be important for biological suitability and in clinical applications, such as materials tomography, ion release and pH changes.     

DEHCH与DINCH环保增塑剂增塑性能对比

目的:通过环己烷-1,2-二甲酸二异辛酯(DEHCH)与环己烷-1,2-二甲酸二异壬酯(DINCH)增塑聚氯乙烯性能的对比,验证DEHCH的增塑效果。方法:用环己烷二甲酸酯类增塑聚氯乙烯粒料,采用高低温拉力机和差示扫描分析仪测试。结果:DEHCH增塑聚氯乙烯的拉伸强度大于DINCH增塑聚氯乙烯,且DEHCH增塑聚氯乙烯的玻璃化温度低于DINCH增塑聚氯乙烯。结论:DEHCH增塑效率优于DINCH,且DEHCH增塑PVC低温下拉伸性能良好。     

香连丸中8种功效成分在小鼠体内的组织分布＊

目的 研究小鼠口服香连丸（Xianglian Pill，XLP）后其功效成分在体内的组织分布，揭示成分在体内不同组织作用趋势，探讨方药作用机制。方法 小鼠灌胃XLP后于不同时间点采集组织（小肠、大肠、肝、心、肺、肾），样品处理后，UPLC-MS/MS检测XLP中8种功效成分的组织匀浆液含量，ACE Excel 3 C18 column（2.1 mm × 100 mm，3 μm），流动相0.1%甲酸水溶液-乙腈梯度洗脱分析物，正离子模式检测。计算成分在各组织的浓度和分布百分比（Distribution percentage，DP）。结果 建立同时检测组织匀浆液中8种XLP功效成分HPL-MS/MS分析方法，该方法专属性、线性、精密度、准确度、回收率、基质效应和稳定性良好。XLP功效成分在小肠组织具有较高浓度（DP > 25%）。小檗碱、黄连碱、巴马汀和药根碱DP值分别为48.5%、30.3%、28.3%和29.3%，显著高于其他组织。吴茱萸碱和吴茱萸次碱在结肠具有高分布，DP值分别为32.7%和27.5%。木香烃内酯和去氢木香内酯主要分布于肺，DP值分别为40.6%和47.5%。结论 XLP生物碱类成分在肠道组织具有高浓度，内酯类成分在肺肠组织具有高分布，该分布趋向有助于揭示方药肠道抗炎和行气缓急止痛作用。     

Fatty acids and lipids of camel milk and colostrum

Total fat content was 32.8 ± 14g/L in camel milk (10-240 days post partum) or 30.1 ± 19.5g/L in colostrum (1-7 days post partum). Triacylglycerols accounted for 96% of the total lipids in milk. Triacyglycerols of camel milk contained saturated fatty acids (66.1/%) and unsaturated fatty acids (30.5%). The predominant saturated fatty acids were 16 : 0 (34.9%) 14 : 0 (14.5%) and 18 : 0 (9.7%). The content of these fatty in acids in colostrum was lower (52.4%) than that of mature milk. The colsotrum contained a relatively high amount of 18 : 1 (25.4%), and 16 : 1 (13.9%), with the remainder being a mixture of dienoic and trienoic long-chain fatty acids. Triacylglycerols contained low amount of short-chain fatty acids (C4-C8). There is a high content of polyunsaturated fatty acids in camel colostrum and milk.