两种树脂基托细菌粘附情况的比较

目的比较BPS注塑树脂和热凝基托树脂表面细菌粘附能力的大小。方法将BPS注塑树脂和热凝基托树脂试件进行细菌体外粘附实验,采用菌落形成单位计数法测定血型链球菌、粘性放线菌和白色念珠菌粘附量的大小。结果培养24h、48h、168h后,各BPS注塑树脂试件组的细菌粘附量均少于热凝基托树脂试件组。结论BPS注塑树脂较热凝基托树脂更能减少血型链球菌、粘性放线菌和白色念珠菌在其表面的粘附。     

微波辐射加热对潘氏细胞染色的影响

潘氏细胞(Paneth Cell)是小肠腺的特征细胞,该细胞有合成分泌蛋白质的特点,其分泌颗粒含有防御素(defensin,又称隐窝素Chyntdin)、溶菌酶,释放后对肠道微生物有杀灭作用[1];同时亦有吞噬功能.潘氏细胞含有的分泌颗粒通常可用酸性染料如焰红(Phloxine)、伊红或橘黄G染色[2],其中以焰红染色效果最佳.     

辐射引发合成高吸水树脂及用于吊兰栽培研究

高吸水树脂是一种能吸收并保持大量植物所需水分和营养成分的,并可重复利用的高分子吸水材料。本实验通过60Coγ射线辐射诱导丙烯酰胺,得到一种新型耐降解吸水树脂。为研究新型吸水树脂对园艺作物吊兰的生长及氮素养分吸收的影响,探索其作为栽培基质-水晶泥的应用前景。本研究采用室内盆栽模拟试验,通过15N同位素示踪技术研究了大（0.75 cm）、中（0.5 cm）、小（0.25 cm）三种粒径水晶泥基质对园艺作物吊兰体内氮素分配及其养分利用效率的影响。结果表明：小粒径水晶泥基质栽培下,叶部的吸氮量占比最大,达到52.169%,增加其观赏性;其次,小粒径水晶泥基质栽培下,吊兰对氮素养分的利用效率最高,达到了32.397%,但与其他两处理间的差异均未达到显著水平。     

亚麻木酚素的微波辅助提取工艺研究

采用微波辅助提取法从脱脂亚麻籽壳中提取亚麻木酚素,以磷钼酸显色的方法定量测定亚麻木酚素,通过单因素试验、中心组合试验及响应面分析,确定微波辅助提取的最优工艺条件为:乙醇浓度40.9%(v/v)、液固比21.9:1(mL/g)、超声处理5 min进行预浸、辐照时间90.5 s、微波功率为130 W。与常规溶剂提取法和索氏提取方法相比,微波辅助提取法显著提高了亚麻木酚素的得率,大大缩短了提取时间,并节省了能耗。     

Fmoc-Asn(Trt)-OH与Wang树脂的合成研究

研究了Fmoc-Asn(Trt)-OH与Wang树脂的酯化反应工艺。探讨了反应策略、溶剂体系、投料比、反应时间以及反应温度等条件对手工合成Fmoc-Asn(Trt)-Wang树脂反应的影响。并用微波辅助方法与常规方法进行了对比。实验结果表明了采用HBTU/HOBt/DIEA方法的连接效率最高。对反应的优化结果为:NMP/DCM体积比为1:7,体系、摩尔比为3:1,每次反应时间4 h,温度40℃。微波对本酯化反应影响不大。     

732树脂吸附蛋白质的机理研究

通过树脂吸附水溶液中蛋白质的试验 ,研究了 732树脂对蛋白质吸附过程机理 ,初步分析了动力学行为 ,包括吸附等温线方程、吸附速率方程、总传质系数、树脂内的有效扩散系数等     

生姜油树脂微囊化的实验研究

用生姜为原料,经连续渗漉抽提的油树脂为心材,以食用胶为壁材,经均质、乳化、喷雾干燥获得生姜油树脂微胶囊,对其主要技术参数测定结果表明:含水率为3.81％,心材包埋率为96.76％,收得率为92.1％。姜油酮含量为1.7285％(WW)。溶剂残留量为4.5ppm。研究中用日立S-450扫描电镜研究了微胶囊的外形结构,未发现微胶囊破裂情况,在姜油酮检测中,用电位滴定法发展和完善了羟胺法。     

欧洲赤松树脂道上皮细胞树脂分泌方式研究(英)

利用高压冷冻和冷冻替代技术对欧洲赤松（PinussylvestrisCarr．）茎皮层成熟树脂道上皮细胞的超微结构进行研究,揭示出一种全新的树脂分泌方式。其分泌过程为：一些含有水解酶的高尔基小泡,转移至质膜周围并释放水解酶,从而将质膜溶解形成分泌通道,树脂由此迅速转移至质膜外,然后,通过高尔基小泡相互融合形成新膜片段的方式来修补破损的质膜。     

不同方式提取松籽油理化性质及微波加热对其品质影响的研究

油脂氧化是导致食品质量下降的主要原因。油脂在微波加热过程品质会发生变化,本研究旨在确定微波加热过程对不同方式提取的松籽油的影响。本文对水酶法和溶剂法提取的松籽油的理化性质及脂肪酸组成进行了分析,两种方法提取的松籽油品质有一定的不同,水酶法松籽油酸值及磷脂含量均低于溶剂法松籽油,而过氧化值高于溶剂法松籽油,提取方法对松籽油脂肪酸组成的影响不显著。同时,研究了在一定功率（700W）下,不同加热时间（1、3、5和7min）对两种方法提取松籽油品质的影响,微波加热3min以上,会导致所有样品品质恶化及组成变化。     

Effect of repeated microwave disinfections on bonding of different commercial teeth to resin denture base

doi: 10.1111/j.1741‐2358.2011.00516.x Effect of repeated microwave disinfections on bonding of different commercial teeth to resin denture base Objective: To verify the influence of repeated microwave disinfections on the shear bond strength of two commercial types of teeth to acrylic resin, when the ridge lap surfaces were unmodified, bur abraded, bur grooved or etched by monomer. Material and methods: Eighty specimens (n = 10) were adhered to the tooth ridge lap surface, polymerised in a water bath at 74°C for 9 h. Microwaved specimens were individually immersed in 150 ml of water and submitted to five simulated disinfections in a microwave oven calibrated at 650 W for 3 min. Control specimens were not microwave treated. Shear bond strength tests were performed in an Instron machine with a cross‐speed of 1 mm/min. The fracture load values were transformed into shear bond strength as a function of the bonding area (0.28 cm²). Data were submitted to anova and Tukey’s test (α = 0.05). Fractured areas were classified as adhesive, cohesive (resin or tooth) or mixed failures. Results: Repeated microwave disinfections increased the shear strength of the tooth/resin bond. Mechanical retention in microwaved and non‐microwaved procedures improved the shear bond strength. Conclusions: The different commercial types of teeth influenced shear bond strength values, with Biotone teeth showing the lower values.     

Effect of pre-processing methods on bond strength between acrylic resin teeth and acrylic denture base resin

doi: 10.1111/j.1741‐2358.2011.00480.x
Effect of pre‐processing methods on bond strength between acrylic resin teeth and acrylic denture base resin Objectives: This study evaluated the effects of various pre‐processing methods on the bond strength between resin and denture teeth. Backgrounds: Debonding of acrylic resin teeth from denture base material is a problem for patients wearing complete dentures. Materials and Methods: Four experimental groups (n = 30) were investigated by subjecting tooth–resin bonding to tensile loading. Specimens were prepared and tested according to the methods of the International Standards Organization (ISO 22112:2005) using a special assembly. Four pre‐processing surface treatments of teeth were applied: (i) ST₁, no treatment applied (control); (ii) ST₂, wax solvent (Dewaks, Faber Kimya & Ilaç, Turkey); (iii) ST₃, boiling water followed by conditioning with methyl methacrylate (MMA) monomer (Meliodent, Bayer Dental, Germany); (iv) ST₄, boiling water followed by wax solvent agent and finally MMA monomer application. Bond strength test was performed using a universal testing machine. Results: All the strength values of the test groups were within clinically acceptable limits. The lowest values were from the ST₁ group and the highest values were in the ST₄ group. Conclusions: Wax elimination methods affected bonding strength. Application of wax solvent and MMA monomer to the ridge lap surfaces of the teeth gave the best results. In clinical practice, this application procedure may decrease the bonding failure of denture teeth.     

Fatigue resistance of acrylic resin denture base material reinforced with E-glass fibres

doi: 10.1111/j.1741‐2358.2011.00548.x
Fatigue resistance of acrylic resin denture base material reinforced with E‐glass fibres Objective: The purpose of the study was to determine the effect of different forms and concentrations (2.5, 3, 4, 5% by volume) of glass fibres (chopped strand mat, continuous and woven) on fatigue resistance of acrylic denture base resin. Material and Methods: The fatigue resistance was measured by applying repeated three‐point bending deflection to the specimens, the cycle frequency of 1.05 g and magnitude of deflection of 2.0 mm. The number of loading cycles needed to cause a fracture in the test specimen was considered the fatigue resistance of the specimen. Results: The results of this study revealed that the addition of three different glass fibre forms at all concentrations to acrylic resin did not produce a statistically significant increase in the fatigue resistance (p ≥ 0.05). This study also revealed that there were significant differences (p < 0.05) between glass fibres forms used concerning the effects on the fatigue resistance. Conclusion: This study showed that the woven glass fibres had a definite superiority over the chopped fibres and the continuous fibres in regard to the fatigue resistance of the acrylic denture base resin.     

Effect of the addition of silanated silica on the mechanical properties of microwave heat-cured acrylic resin

doi: 10.1111/j.1741‐2358.2011.00604.x
Effect of the addition of silanated silica on the mechanical properties of microwave heat‐cured acrylic resin Objectives: The purpose of this study was to evaluate fthe flexural strength and Vickers hardness of a microwave energy heat‐cured acrylic resin by adding different concentrations of silane surface‐treated nanoparticle silica. Methods: Acrylic resin specimens with dimensions of 65 × 10 × 2.5 mm were formed and divided into five experimental groups (n = 10) according to the silica concentration added to the acrylic resin mass (weight %) prior to polymerisation : G1, without silica; G2, 0.1% silica; G3, 0.5% silica; G4, 1.0% silica; and G5, 5.0% silica. The specimens were submitted to a three‐point flexural strength test and to the Vickers hardness test (HVN). The data obtained were statistically analysed by anova and the Tukey test (α = 0.05). Results: Regarding flexural strength, G5 differed from the other experimental groups (G1, G2, G3 and G4) presenting the lowest mean, while G4 presented a significantly higher mean, with the exception of group G3. Regarding Vickers hardness, a decrease in values was observed, in which G1 presented the highest hardness compared with the other experimental groups. Conclusion: Incorporating surface‐treated silica resulted in direct benefits in the flexural strength of the acrylic resin activated by microwave energy; however, similar results were not achieved for hardness.     

Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin

doi:10.1111/j.1741‐2358.2009.00333.x
Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin Objective: The purpose of this study was to verify the effect of microwave treatment on the shear bond strength of commercial types of teeth to acrylic resin, when the glossy ridge laps were unmodified (groups 1 and 5), bur abraded (groups 2 and 6), bur grooved (groups 3 and 7) or etched by monomer (groups 4 and 8). Background: Controversial findings have shown that mechanical or chemical changes in ridge‐lap surface of the tooth increase or decrease the bond strength between tooth and acrylic resin, and the microwave disinfection may cause different changes on this bond strength. Materials and methods: Eighty specimens (n = 10) were made with the acrylic resin bonded to tooth glossy ridge lap, polymerised in water at 74°C for 9 h, and deflasked after flask cooling. Specimens of the groups 5, 6, 7 and 8 were individually immersed in 150 ml of water and submitted to microwave treatment in an oven at 650 W for 3 min. Control specimens (groups 1, 2, 3 and 4) were not microwave treated. Shear bond strength test was performed in an Instron machine with a cross‐speed of 1 mm/min. Collected data were submitted to anova and Tukey’s test (α = 0.05). Results: Microwave treatment decreased the shear bond strength values of the tooth/resin bond. In the microwaved and non‐microwaved procedures, mechanical retention improved the shear bond strength when compared with the control and monomer treatments. Conclusion: Shear bond strength of the tooth/resin bond was influenced by the microwave treatment and different commercial teeth association, and was lower for the Biotone tooth.     

The application of microwave heating to the synthesis of 6-amino-6-deoxycellulose

Microwave heating was applied to the reactions involved in the synthesis of 6-amino-6-deoxycellulose, 4. These included, cellulose solubilization, bromination at C-6, displacement of bromine with azide ion, and reduction of the azido group to an amino group. Compared to conventional heating, this approach had the advantages of shortening reaction times and retaining the degree of polymerization of 4.     

Automated ‘X‐Y’ robot for peptide synthesis with microwave heating: application to difficult peptide sequences and protein domains

Precise microwave heating has emerged as a valuable method to aid solid‐phase peptide synthesis (SPPS). New methods and reliable protocols, as well as their embodiment in automated instruments, are required to fully use this potential. Here we describe a new automated robotic instrument for SPPS with microwave heating, report protocols for its reliable use and report the application to the synthesis of long sequences, including the β‐amyloid 1‐42 peptide. The instrument is built around a valve‐free robot originally developed for parallel peptide synthesis, where the robotic arm transports reagents instead of pumping reagents via valves. This is the first example of an ‘X‐Y’ robotic microwave‐assisted synthesizer developed for the assembly of long peptides. Although the instrument maintains its capability for parallel synthesis at room temperature, in this paper, we focus on sequential peptide synthesis with microwave heating. With this valve‐free instrument and the protocols developed for its use, fast and efficient syntheses of long and difficult peptide sequences were achieved. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.     

Comparison of bacterial growth to high-intensity microwave exposure and conventional heating

Escherichia coli pol A⁺ and pol A^? strains were exposed to 8.8-GHz microwaves pulsed at 1,000 Hz (1-μs pulse width) and an SAR of 40 W/kg, which increased the temperature of the cell culture by 7 °C. Two-way analysis of variance showed no significant difference between the growth rates of microwave irradiated and thermally exposed cells.     

Some considerations when using a microwave oven as a laboratory research tool

Microwave ovens can be used in laboratories for the rapid heating of material – either to dry them completely or to subject a workpiece to sudden thermal stress or electric field stress. Determinations of the moisture content levels in soil or leaf tissue samples, for example, can be made within tens of seconds rather than hours. It is often assumed that placing a load within a microwave oven will result in it being heated evenly as well as quickly, but this is not always the case. This paper describes how a microwave oven works and illustrates how the heating effect within a workpiece can vary. The size and shape of a sample as well as its physical properties determine the power absorption. Equal volumes of water in different shaped containers attain different final temperatures and a tall, cylindrical water load is shown to have different temperatures at different levels. Most microwave ovens do not have a true, variable power capability, but rely on an on/off timing ratio to vary mean power. If this is not appreciated, then erroneous conclusions might be drawn from a set of experiments involving different power levels. Changes in mains supply voltage can affect the amount of energy dissipated in a load. This may introduce variations in results if experiments are conducted over a period of several hours. Experiments are described which illustrate these effects and some criteria and working practices are suggested to improve the consistency and reliability of results when using a microwave oven as a research tool.