Effect of addition of chitosan to self-etching primer:antibacterial activity and push-out bond strength to radicular dentin

The purpose of this study was to evaluate the antibacterial activity of a modified self-etching primer incorporating chitosan and whether this modification affected the bond strength to radicular dentin.A modified self-etching primer was prepared by adding chitosan solutions at 0.03%,0.06%,0.12% and 0.25%（W/W） to RealSeal selfetching primer.RealSeal primer without chitosan was used as the control.The antibacterial activity of the modified self-etching primer was evaluated using the direct contact test against Enterococcus faecalis.The bonding ability of the RealSeal system to radicular dentin was evaluated using the push-out bond strength test.The modes of failure were examined under a stereomicroscope.Data were analyzed using analysis of variance（ANOVA） and Tukey’s test,with a P-value 〈 0.05 indicating statistical significance.The results showed that the antibacterial properties of the freshly prepared and aged modified self-etching primer incorporating chitosan exhibited potent antibacterial effect against Enterococcus faecalis compared with the unmodified primer.The RealSeal system with the aged modified self-etching primer incorporating chitosan showed no significant differences in the bond strength as compared with the control（P = 0.99）.The findings suggest that modified self-etching primer incorporating chitosan is a promising antibacterial primer which does not adversely affect the bond strength of the RealSeal system to radicular dentin.

An in-situ self-etching enabled high-power electrode for aqueous zinc-ion batteries

Sluggish storage kinetics is considered as the main bottleneck of cathode materials for fast-charging aqueous zinc-ion batteries(AZIBs).In this report,we propose a novel in-situ self-etching strategy to unlock the Palm tree-like vanadium oxide/carbon nanofiber membrane(P-VO/C)as a robust freestanding electrode.Comprehensive investigations including the finite element simulation,in-situ X-ray diffraction,and in-situ electrochemical impedance spectroscopy disclosed it an electrochemically induced phase transformation mechanism from VO to layered Zn_(x)V_(2)O_5·nH_(2)O,as well as superior storage kinetics with ultrahigh pseudocapacitive contribution.As demonstrated,such electrode can remain a specific capacity of 285 mA h g^(-1)after 100 cycles at 1 A g^(-1),144.4 mA h g^(-1)after 1500 cycles at 30 A g^(-1),and even 97 mA h g^(-1)after 3000 cycles at 60 A g^(-1),respectively.Unexpectedly,an impressive power density of 78.9 kW kg^(-1)at the super-high current density of 100 A g^(-1)also can be achieved.Such design concept of in-situ self-etching free-standing electrode can provide a brand-new insight into extending the pseudocapacitive storage limit,so as to promote the development of high-power energy storage devices including but not limited to AZIBs.

Effect of Multiple Coatings of One-step Self-etching Adhesive on Microtensile Bond Strength to Primary Dentin

Objective To investigate the effect of multiple coatings of the one-step self-etching adhesive on immediate microtensile bond strength to primary dentin.Methods Twelve caries-free human primary molars were randomly divided into 2 groups with 6 teeth each.In group 1,each tooth was hemisected into two halves.One half was assigned to control subgroup 1,which was bonded with a single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 1 in which the adhesive was applied three times before light curing.In group 2,the teeth were also hemisected into two halves.One half was assigned to control subgroup 2,which was bonded with the single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 2 in which three layers of adhesive were applied with light curing each successive layer.Microtensile bond strength was immediately tested after specimen preparation.Results When the adhesive was applied three times before light curing,the bond strength of the experimental subgroup 1(n=33,57.49±11.61 MPa) was higher than that of the control subgroup 1(n=31,49.71±11.43 MPa,P<0.05).When using the technique of applying multiple layers of adhesive with light curing each successive layer,no difference of immediate bond strength was observed between the control subgroup 2 and the experimental subgroup 2(P>0.05).Conclusion Multiple coatings of one-step self-etching adhesive can increase the immediate bond strength to primary dentin when using the technique of light-curing after applying three layers of adhesive.

Effect of Saliva Contamination on Shear Bond Strength of Orthodontic Brackets When Using a Self-Etch Primer

The effect of saliva contamination on the shear bond strength of orthodontic brackets, at various stages of the bonding procedure using a new self-etch primer was studied. The samples were divided into 4 groups according to 4 different enamel surface conditions: Group A: dry; Group B: saliva contamination before priming; Group C: saliva contamination after priming, and Group D: saliva contamination before and after priming. Stainless steel brackets were bonded in each test group with a light-cured composite resin (TransbondXT 3M). The shear bond strength was determined in the first 30 min after bonding. The analysis of variance indicated that the shear bond strengths of the 4 groups were significantly different (F=11.89, P<0.05). Tukey HSD tests indicated that contamination both before and after the application of the acid-etch primer resulted in a significantly lower (=4.6±1.7 MPa) shear bond strength than either the control group (=8.8±1.9 MPa) or the groups where contamination occurred either before (=7.9±2.0 MPa) or after (=6.9±1.5 MPa) the application of the primer. It was concluded that the new acid-etch primer could maintain adequate shear bond strength if contamination occurred either before or after the application of the primer. On the other hand, contamination both before and after the application of the primer could significantly reduce the shear bond strength of orthodontic brackets.

Multiple Coatings can Improve the Bond Durability of One-step Self-etching Adhesive to Primary Dentin

Objective To investigate whether multiple coatings can improve the bond durability of one-step self-etching adhesive to primary dentin. Methods Twelve caries-free human primary molars were randomly divided into 2 groups. In group 1, each tooth was hemisected into 2 halves. One half was assigned to the control subgroup 1, which was bonded with a commercially available one-step self-etching adhesive according to the manufacturer＇s instruc- tions; the other half was assigned to experimental subgroup 1, in which the adhesive was applied three times before light curing. In group 2, one split half tooth was bonded with a commercially available one-step self-etching adhesive according to the manufacturer＇s instructions; for the other half, three layers of adhesive were applied with each successive layer of light curing. Specimens were stored in 0.9% NaC1 containing 0.02% sodium azide at 37℃ for 18 months and then were subjected to microtensile bond strength test and the fracture mode analysis. Results When the adhesive was applied three times before light curing, the bond strength of the ex- perimental subgroup 1 was significantly higher than that of the control subgroup 1 （47.46__＋13.91 vs. 38.12＋11.21 MPa, P〈O.05）. When using the technique of applying multiple layers of adhesive with each successive layer of light curing, no difference was observed in bond strength between the control subgroup and the experimental subgroup （39.40＋8.87 vs. 40.87-＋9.33 MPa, P〉O.05）. Conclusion Multiple coatings can improve the bond durability of one-step self-etching adhesive to primary dentin when using the technique of light-curing after applying 3 layers of adhesive.

应用PRIMER软件进行浮游植物群落结构的多元统计分析

根据青岛近海进行的一次添加营养盐的围隔实验数据,采用专业软件PRIMER中的多元统计分析方法,进行了浮游植物群落结构的变化研究。结果表明,虽然由于本实验中浮游植物的生长受到Si的限制,硅藻类群不占明显的优势,使得优势种随时间的变化不明显,没有出现明显的群落演替,但用PRIMER软件的聚类分析(Clustering)和多维尺度转换排序(MDS)分析表明,添加营养盐后浮游植物群落结构有较明显的变化,同时,PRIMER软件的相异系数(ANOSIM)分析也表明,在同时添加N、P的围隔内,浮游植物群落结构变化较只添加P的围隔中的变化显著。这显示了PRIMER软件在分析浮游植物群落结构变化和评价水域富营养化中的应用前景。

多元统计软件PRIMER在张网渔具种类选择性研究中的运用

本文根据2014年秋季青岛斋堂岛海域双桩竖杆张网的网囊网目选择性试验数据,运用PRIMER软件中的相似性分析、非参数多维标度分析和相似性百分比分析模块分析了张网渔具种类选择性。试验采用平行作业法,以传统网具(2a=16mm的菱形目网囊)作为对照网,设计了网目尺寸(2a)为30和35mm的菱形目网囊(以30D和35D表示)和网目尺寸(2a)为20、30和35mm的方形目网囊(以20S、30S和35S表示),进行选择性实验。研究显示:(1)35D、30S和35S渔获组成与对照网存在显著性差异,其余各网之间差异不显著。(2)改良后的试验网具能有效释放舒氏海龙;除20S组外,其余各试验网对方氏云鳚亦有较好的释放效果。(3)方形目网囊较相同尺寸的菱形目网囊具有更好的种类选择性;对相同网目形状的试验网囊进行比较,种类选择性随网目尺寸的增大而增大。(4)综合分析不同网具的渔获物组成和规格,在斋堂岛海域秋季小黄鱼、带鱼渔汛期,推荐使用30mm方形目网囊;方氏云鳚渔汛期,推荐使用20mm方形目网囊进行捕捞作业。研究结果表明,运用多元统计软件PRIMER进行张网渔具种类选择性分析虽然存在待完善之处,但该方法为本领域研究提供了有益参考。

DNA Extraction and ISSR Primer Screening of Camellia chekiangoleosa

[Objective] The aim was to screen out simple methods of DNA extraction and effective ISSR primers suitable to all germplasm materials of Camellia chekiangoleosa.[Method] The modified CTAB method was used in the extraction of the genomic DNA,50 ISSR primers from other Camellia plants were used in the ISSR-PCR amplification for 20 germplasm materials from 10 populations in Fujian,Zhejiang,Jiangxi and Anhui Province.[Result] Pure DNA could be obtained rapidly by using the improved CTAB method,and the 20 selected effective primers had rich polymorphism,clear bands and good repeatability.337 DNA bands were obtained,of which 281 bands were polymorphic,accounting for 83.4% of the total amplified bands.And 16.85 bands could be amplified with a primer,averagely.[Conclusion] The selected 20 primers could be effectively applied to ISSR analysis of the germplasm resources of C.chekiangoleosa in Zhejiang.

利用软件Primer Premier 5.0进行PCR引物设计的研究

目的 运用PrimerPremier 5 0软件设计PCR引物 ,并且检验所设计引物的PCR扩增效率和特异性。方法 运用PrimerPremier 5 0软件设计 16对猪和犬的PCR扩增引物 ,通过PCR扩增后进行琼脂糖凝胶电泳检测实验结果。结果 在所设计的 16对引物中有 8对PCR扩增特异性好且效率高 ,成功率 5 0 %。但是 ,其中早期设计引物 12对只有 4对成功 ,后期设计引物 4对全部成功。结论 从引物设计的过程中可以看到一种趋势 -后期引物设计的成功率远远高于早期。这表明我们在引物设计方面正在逐步成熟 。

Designing Primers for H5 and H7 Subtypes of Avian Influenza Virus and Multiplex RT-PCR Amplification

[Objective] The research aimed to design primers that are suitable for detecting H5 and H7 subtypes of avian influenza virus （AIV） ; [Method] DNAStar was used to analyze the homology of the sequences of H5 and H7 subtypes of AIV accessed in GenBank, and design primers（ by Primer Premier 5.0） on high homologous region of these sequences, and then amplified by RT-PCR. [Result] The multiplex RT-PCR amplification, agarose gel electrophoresis and sequencing results showed that the self-designed primers are successful for detecting AIV. [Conclusion] It is feasible to rapidly diagnose AIV through this method.

利用MPprimer设计引物并优化扩增条件以提高多重PCR效率的实验研究

多重PCR技术广泛应用于多个研究领域,其中引物设计及扩增条件是提高多重PCR实验效率的关键因素.为探讨优化多重PCR实验的方法,以小鼠5个看家基因为研究对象,使用实验室新近开发的MPprimer程序设计多重PCR引物,并通过改变多种反应条件来优化多重PCR实验.结果表明,MPprimer程序能够设计出理想的多重PCR引物,并且通过对退火温度及延伸时间进行优化,可显著提高多重PCR实验效率,对于提高基因表达的规模化检测能力具有积极的促进作用.

Screening of SSR Core Primers for Purity Identification of Pepper(Capsicum) Hybrids

[Objective] This study aimed to screen a set of SSR core primers suitable for purity identification of pepper （Capsicum） hybrids. [Method] DNA fingerprint of 100 pepper hybrids was analyzed using 17 SSR primers. [Result] According to the polymorphism and heterozygosity, Hpms1-214, Es395 and Hpmsl-5 were determined as three preferred core primers for purity identification of pepper hybrids. By using these three preferred core primers, 97 pepper hybrids （accounting for 97%） had heterozygous band pattern with at least one primer. Es330, Es363, Epms923, Es120 and Es64 were determined as candidate core primers for purity identification of pepper hybrids. Specific primers of 14 varieties were obtained, which could be used to further screen parent-complementary primers of each pepper hybrid. [Con- clusion] This study laid the foundation for constructing standard DNA fingerprints for purity identification of pepper hybrids.

Primer Screening on Germplasm Resources of Mallotus oblongiolus by ISSR Molecular Marker

[ Objective] To provide effective primers for the rapid and accurate ISSR analysis of the germplasm materials of Mallotus oblongiolus （Miq.） Muello-Arg.. [Method] The modified CTAB method was used in the extraction of the genomic DNA. 99 ISSR primers were used in the ISSR-PCR amplification for 20 germplasm materials from 10 populations in Hainan Island, so that some primers, which were suitable to all gerplasm materials of M. oblongiolu, could be selected. [ Result] 15 effective primers with characteristics of rich polymorphism, clear bands, and good repeatability were selected from 99 test primers. The 15 primers selected were used in the ISSR-PCR amplification for 66 germplasm materials of M. oblongiolus. From all of which the abundant and distinct DNA fingerprintings could be obtained. 286 DNA bands were obtained, and of which 231 bands were polymorphic, which amounted to 80.77% of the total bands amplified. And 19.1 bands could be obtained with each primer, averagely. [ Conclusion] The 15 primers selected could be effectively applied to ISSR analysis of the germplasm resources of M. oblongiolus.

Resilon/Epiphany Self-Etch根管充填效果的X线观察

目的:评价Resilon/Epiphany Self-Etch(RESE)在根管治疗术中的充填质量。方法:收集30颗因牙周病或正畸治疗需要拔除的离体下颌前磨牙,随机分为2组,牙胶/AH plus组16颗牙,RESE组14颗牙。经常规开髓拔髓、根管预备后,实验组以RESE充填根管,对照组以牙胶/AH plus充填根管。根管充填完毕摄X线牙片计分评价2种材料根管充填的影像质量。结果:2种充填材料颊舌向X线评价均高于近中远中向(P<0.05),颊舌向X线观察2种充填材料没有差异(P>0.05);近远中向X线观察RESE组根充的影像质量好于牙胶/AH plus组(P<0.05)。结论:RESE充填系统具有良好的X线阻射性,有利于通过X线片观察其根管充填效果。

大型多元统计软件PRIMER的方法原理及其在底栖群落生态学中的应用

本文阐述大型多元统计分析软件 PRIMER的原理及其在底栖生态学中的应用。PRIMER是处理生态和环境多元数据的重要数值分析工具 ,本文从实用的角度对其中包括的技术方法和相应的子程序如 :等级聚类 (CLUSTER)、非度量多维标度 (MDS)、主分量分析 (PCA)、相似性分析检验(ANOSIM)、相似性百分比分析 (SIMPER)、生物 -环境连接的逐步分析和相关检验 (BIOENV/BVSTEP)等作了较为系统的介绍。

Application of Abnormal Touchdown PCR with High Degeneracy Primer in Amplification of Large-Family Genes

[Objective] The aim was to explore the special methods for amplification of large-family genes by using primers with high degeneracy.[Method] By using the primers with high degeneracy,conventional PCR,conventional touchdown PCR and the optimized abnormal touchdown PCR were respectively carried out to amplify the genomic DNA of Cyprinus carpio.[Result] Only one evident electrophoretic band and a few Sox genes were obtained by using normal PCR;no obvious electrophoretic band but dispersive product was obtained by normal touchdown PCR;ideal result was obtained by the abnormal touchdown PCR that three evident electrophoretic bands and much more Sox genes were amplified.[Conclusion] The research provided theoretical basis for the optimization and selection of PCR amplification conditions of the large-family genes.

基于半导体桥芯片的钝感高瞬发底火设计

针对超高速射武器弹药对高频高安全及高一致性点火的发展需求,基于半导体桥芯片点火技术,设计了一种新型钝感高瞬发底火。通过对比研究4种半导体桥芯片及其2种封装结构,选用斯蒂芬酸铅和亚铁氢化铅/高氯酸钾作为两级复合装药,优化形成了模块化结构的半导体桥底火样机。该底火满足了与弹药接口的匹配要求,并达到1 A 1 W 5 min不发火的安全性要求。发火性能试验表明,所研制的半导体桥底火作用时间不大于200μs,散布不大于30μs,与传统桥丝电底火相比瞬发度和作用时间一致性显著提高,综合性能更好。

利用Primer Premier 5.0进行引物设计

目前，PCR引物设计大都通过计算机软件进行。本文详细的介绍了怎样利用“Primer Premier5．0”软件进行PCR引物设计。

Primer Extension-DHPLC检测线粒体DNA 12SrRNA常见耳聋相关突变方法的建立~△

目的建立针对线粒体DNA 12SrRNA基因常见耳聋相关突变的Primer Extension-DHPLC(PE-DHPLC)基因诊断新方法。方法将包含线粒体DNA 12SrRNA 961insC、T1095C、C1494T、A1555G 4种不同突变的4例外周血DNA样本和4例正常对照标本经测序验证,PCR扩增靶序列,设计延伸引物,延伸后得到线粒体DNA 12SrRNA基因961insC、T1095C、C1494T、A1555G 4个常见突变的特异性延伸片段,用全变性高效液相色谱分析延伸片段混合物,分离图谱鉴定被检样本的基因型。结果 4例包含线粒体DNA 12SrRNA基因4种耳聋相关突变的DNA样本均扩增出包含4种突变的975 bp特征性条带,PE-DHPLC检测结果显示突变者有引物峰和突变峰两个峰,完全可以鉴别出4种突变,而4例正常对照标本仅显示单个引物峰。结论本实验建立了Primer Extension-DHPLC的线粒体相关耳聋突变分析新方法,可用于耳聋的基因诊断。

3'-terminus shifted bases degeneracy primers increasing sensitivity of polymerase chain reaction

目的:通过使用3’末端碱基游移混合引物,减少引物末端错配,提高多变区基因片段的PCR检测阳性率。方法:在HBV DNA P基因区设计一对检测阳性率相对较高的引物(原型引物),在原型引物序列基础上将两根引物的3’末端分别截去1个或2个碱基,设计出两对参数与原型引物近似的突变引物。分别单独用原型引物和原型引物与突变引物组成的混合引物,在相同条件下对27份HBV DNA阳性标本行PCR,比较二者阳性率。用混合引物扩增4例拉米呋丁治疗无效患者血清HBV DNA,将扩增产物测序并评价3’末端错配对PCR的影响。结果:原型引物和混合引物检测阳性率分别为70.4％(19/27)和85.2％(23/27),两者差异非常显著(P<0.05)。引物3’末端错配能导致PCR假阴性。结论:扩增保守性相对较差的基因片段,采用3’末端单个或多个碱基截短的引物,构成3’末端碱基游移混合引物,可以避免因3’末端错配产生的PCR假阴性,提高检测阳性率。