Advanced Materials Research Vols. 884-885

Abstract: Objective: To study the surface characteristics, chemical composition and Ni release from simulated standard fixed orthodontic appliance ligated with two differently priced nickel titanium (NiTi) archwires in artificial saliva at pH 5.14 and 6.69 for 4 weeks at 37oC. Materials and Methods: Two commercial NiTi rectangular wire (Ormco and Smart), 0.016 x 0.022 in size were studied. Their surface characteristics were evaluated: surface morphology by scanning electron microscope, surface roughness by surface roughness tester and grain structure analysis by optical microscope. Their chemical composition was analyzed by an energy dispersive X-ray spectrometer (EDC). For Ni release, twenty-eight simulated standard fixed orthodontic appliance samples sets, each set corresponding to one half-maxillary arch were used. Sample sets were divided in 2 groups (14 sets per group). The first group was ligated with Ormco NiTi archwires (USA) and the second with Smart NiTi archwires (China) with elastomeric ligatures. Half sets of each group were immersed in 50 ml artificial saliva at pH 5.14, and the other half at pH 6.69. Ni release was quantified with the use of flame atomic absorption spectrophotometry. Statistical analysis of variance was determined on days 1, 4, 7, 9, 14, 21 and 28 comparing Ni release between the groups and t-test was determined the difference between pH 5.14 and pH 6.69. Results: The suface morphology showed striations along the longitudinal axes. The Ormco NiTi wire had more surface roughness than Smart NiTi wire and the diameter of grain sizes were 2-8 μm. The chemical composition of the two NiTi wires was Ni, Ti, Cu, Al, and Cr but there was difference in the percentage of elements. Both Ormco NiTi and Smart NiTi wires continuously increased Ni release at time intervals at both pH levels. The Ormco NiTi wire had more Ni release at pH 6.69 than pH 5.14 but Smart NiTi wire had more Ni release at pH 5.14 than 6.69. At 4 weeks, the Ni release of one half-maxillary arch was 1.221 ppm (1221 μg/l) at pH 5.14, 1.267 ppm (1267 μg/l) at pH6.69 for Ormco NiTi wire and 2.175 ppm (2175 μg/l) at pH 5.14, 0.676 ppm (676 μg/l) at pH 6.69 for Smart NiTi wire. No significant difference was found in Ni release from Ormco and Smart NiTi wires at pH 5.14. At pH 6.69, no significant difference was found in Ni release from Ormco NiTi wires while Smart NiTi wire showed significant difference (p <0.05) on days 14, 21 and 28. Conclusion: Ni release depends on surface characteristics and chemical composition of archwires and pH.

Abstract: Abstract. In order to obtain a chlorogenic acid platinum complex, The intermediate Pt(C6H14N2)(H2O)2(NO3)2 solution was synthesized from Pt(C6H14N2)I2 and AgNO3, and it was treated with the anion exchange resin to give the key intermediate Pt(C6H14N2)(OH)2. The key intermediate was subsequently reacted with chlorogenic acid in butyl alcohol. The complex structure and component were characterized by elemental analysis, ESI-MS, 1H-NMR and IR and the anticancer activity was measured by MTT method. The result showed that its structure was consistent with the title compound and had inhibiting effect on the growth of tumor cell lines in vitro.

Abstract: The purification of industrial alkali lignin with xylanase was investigated. Then the treated lignin was analyzed by ultraviolet (UV) and Fourier transform infrared spectroscopy (FT-IR). The structure change of lignin-carbohydrate complexes (LCC) in industrial alkali lignin was also studied. The results indicate that the content and the purity of lignin increased. And LCC can be broken by xylanase. This will make the applications and development of using lignin as reactive sites and biodegradability inducing sites more advantageously.

Abstract: The isopropylamine with low boiling point was used for preparing GPC from natural lecithin under mild conditions, it was confirmed as an effective catalyst and the recovery can be combined with the recovery of methanol by distillation. The mechanism of the transesterification reaction was proposed and the experiments obtained the better effect under the conditions of: catalyst content was 2.4% of the total reaction volume, lecithin concentration was 0.05-0.10mol L¹ , reaction temperature was 60 °C and reaction time was 260 min.

Abstract: In order to study the the structure-AChE inhibitory activity relationships of 7H-thiazolo [3,2-b]-1,2,4-triazin-7-one derivatives, the 7H-thiazolo[3,2-b]-1,2,4-triazin-7-ones were designed by molecular docking, and readily prepared via a one-pot reaction in N-methyl pyrrolidone hydrosulfate ([Hnmp]HSO₄) lonic liquid. The study of AChE inhibitory activity was carried out using the Ellman colorimetric assay with huperzine-A as the positive control drug. Most of the target compounds exhibited more than 50% inhibition at 10μM.

Abstract: The aim of the present study was to analyze and compare contents of copper, zinc and chromium in 15 kinds of wild mushrooms. heavy metals were determined using flame atomic adsorption spectrometry (VARIAN, SpectrAA-220Fs). The mushrooms were collected from Miyi, China. The study explored the accumulation of heavy metals in different macrofung. Minimal and maximal concentrations of heavy metals were determined in Termitomyces microcarpus and Amanita esculenta for copper, Ramaria flava and Termitomyces for zinc, Hygrophorus eburnesus and Boletus aereus for chromium ,respectively. chromium values in wild mushrooms collected from Miyi were generally higher than the previous studies. Copper and zinc contents were in agreement with the literature value.

Abstract: Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a ubiquitous enzyme in glycolysis that catalyzes an important energy-yielding step in carbohydrate metabolism in the cytoplasm. Independent of its glycolytic activity, evident shown that GAPDH playing roles in several non-metabolic processes such as control of gene expression in response to various stimuli. Moreover it has been shown to be regulated at the transcriptional levels in response to various stimuli, including ROS-triggered responses. In this study, we demonstrated that the mRNA expression of a cytoplasm GAPDH (GAPC2) in response to blast infection in rice leave. The result suggested that the expression of this gene may relative to the disease resistance.

Abstract: Objective: This study aimed to determine and compare the diameter, mechanical properties (tensile strength: flexural strength, flexural modulus of elasticity, 0.2% yield strength and springback: three point bending test: bending stiffness and 0.1mm. offset bending force) and chemical properties (composition and corrosion resistance) of three commercial orthodontic round stainless steel wires. Materials and Method: The samples of this study are three commercial brands of orthodontic round stainless steel wires, Highland (USA), Dentaurum (Germany) and W&H (China), 0.016 inch and 0.018 inch in size. The diameter was measured by micrometer and the mechanical properties were analyzed with tensile strength and three point bending test by Universal Testing Machine according to ISO 15841:2006. The composition was evaluated by Energy Dispersive X-ray Spectrometer (EDS) and the corrosion resistance was analyzed by a potentiodynamic polarization technique according to ISO 10271:2001. The data were analyzed with the Kolmoforov-Smith test, One-way ANOVA and Tukeys test. Results: There were significant differences (p<0.05) in diameter of the three commercial brands of orthodontic round stainless steel wires in both size except 0.016 in diameter between Dentaurum and Highland stainless steel wire. In terms of tensile strength, there were significant differences (p<0.05) in the flexural strength, flexural modulus of elasticity and springback in each variable, except W&H stainless steel wire with flexural strength in 0.016 and 0.018 wire size and springback in 0.018 wire size. However, in 0.2% yield strength, there was no significant difference in each brand and size except Dentaurum and Highland stainless steel in 0.018 wire size. For the three point bending test, there were significant differences (p<0.05) in bending stiffness and 0.1mm. offset bending force of each brand and size except 0.1mm. offset bending force between Dentaurum and Highland stainless steel in 0.016 wire size. In terms of chemical properties, there were the same elements but difference was found in percentage of each element, and W&H stainless steel had the least corrosion resistance. Conclusion: There were significant differences among three commercial orthodontic stainless steel wires in diameters, mechanical properties and chemical properties which will produce different force on each wire during tooth movement. All three brands, however, are acceptable for orthodontic use. The orthodontist should be aware of these differences in using stainless steel for orthodontic treatment.

Abstract: Objective: To evaluate the protective effects of ginsenoside Rb1 mixed with LPD compared to mixed with several other lung flush solutions on ischemia-reperfusion injury. Method: Three group of rabbit lungs were perfused with three kinds of mixtures of ginsenoside Rb1 with blood, Euro-Collins solution(EC) or low-potassium-dextran solution(LPD) respectively, then lung dry/wet weight ratio and malondiadehyde(MAD) were examined and histological changes were observed. Result: Lung dry/wet weight ratio of LPD and Rb1 group was higher than that of EC and Rb1 and blood and Rb1 groups, whereas MAD of LPD and Rb1 group was significantly less than that of EC and Rb1 and blood and Rb1 groups（P<0.05）. Histological findings showed less damage in LPD and Rb1 group. Conclusion: Ginsenoside Rb1 mixed with LPD shows a better protective effect on pulmonary ischemia-reperfusion injury compared with other mixtures.

Abstract: The sealed tube melt polymerization method was employed to synthesize four-arm star polymer PLGA, by which drug-loaded microspheres for cucurbitacin B were prepared. Taking drug loading amount and entrapment effiency as the indicators, drug-loading formulation was optimized.