隐形义齿对基牙龈沟内菌群的影响

目的将隐形义齿与传统卡环固位式可摘局部义齿进行对比,探寻隐形义齿对基牙龈沟内菌群的影响,从而指导活动义齿的选择和设计。方法下颌第一磨牙缺失的患者随机分成3组。分别戴用弯制卡环式可摘局部义齿、铸造卡环式可摘局部义齿和隐形义齿。定时对基牙龈沟进行取样并行细菌培养,并统计细菌总量、专性厌氧菌检出率以及G-菌检出率。结果戴牙后同期相比,隐形义齿组与传统卡环固位式可摘局部义齿相比,基牙龈沟内细菌总量更大,专性厌氧菌检出率及G-菌检出率更高,差异具有统计学意义。结论上述研究结果说明:相较于传统卡环固位式可摘局部义齿,隐形义齿对基牙龈沟内菌群的影响更大。对于牙周状况不佳的患者应当谨慎使用隐形义齿作为修复方式。     

牙龈组织与钛骨内牙种植体的附着

牙龈与牙种植体颈部的附着是影响牙种植体长期功效的重要因素之一,钛是一种非常理想的牙种植生物材料,在临床上得到较广泛的应用。本文就牙龈组织与种植体钛面的附着、附着机理、种植体钛面的性质、结构对龈附着的影响等研究现状作一综述。     

MAR介导的非病毒附着体载体的研究进展

附着体载体可以使外源基因在宿主细胞中不整合到基因组上而是以附着体的形式存在,是一种新型的高效、安全、附着体表达载体。目前研究较多的是由S/MAR(Scaffold/Matrix Attachment Region,S/MAR)元件介导的质粒。虽然此类载体均能介导载体附着存在,但是转基因的表达量不同。最近研究发现,载体的启动子、骨架结构、CpG基序以及表达系统等方面能够影响转基因的表达,针对以上内容作一综述,希望据此进一步优化载体,为临床研究提供基础依据。     

用于基因治疗的非病毒附着体载体研究进展

基因转移载体在基因治疗中起着关键的作用.非病毒附着体载体可以附着而非整合到宿主细胞染色体上,克服了病毒载体及整合载体带来的副作用,是目前安全、理想的可用于基因治疗的表达载体.然而,其低克隆形成率、低表达量和低拷贝数限制了其在基因治疗中的应用.自第一代非病毒附着体载体构建以来,采用截短核基质附着区(matrix atta...     

磁性附着体用于牙列缺损修复的临床观察及对牙周微生态的影响

目的:研究磁性附着体用于牙列缺损修复的临床效果及对牙周微生态的影响。方法:选取2014年8月至2015年8月我院接诊的80例牙列缺损患者作为研究对象,按照随机数表法分为观察组40例和对照组40例。对照组采用常规修复,观察组采用磁性附着体治疗,观察两组患者治疗后固定力、咀嚼效力、舒适程度、语言功能、外观及牙周微生态。结果:治疗后,观察组固定力、咀嚼效力大于对照组[(4.07±0.38)N vs(3.10±0.29)N,(0.80±0.23)%vs(0.59±0.21)%],两组比较差异具有统计学意义(P0.05);观察组舒适程度、语言功能、外观均优于对照组[(4.21±0.45)score vs(3.10±0.42)score,(4.79±0.50)score vs(3.90±0.42)score,(3.98±0.61)score vs(2.76±0.56)score],两组比较差异具有统计学意义(P0.05);观察组PLI、PD显著小于对照组[(1.34±0.31)°vs(1.49±0.43)°,(1.53±0.29)mm vs(1.67±0.32)mm],两组比较差异具有统计学意义(P0.05)。结论:磁性附着体治疗牙列缺损疗效显著,能够减少对牙周组织的损伤,提高舒适度和咀嚼功能。     

大亚湾人工鱼礁附着生物的初步研究

1988年8月至1989年7月在大亚湾鱼礁区进行附着生物调查研究,记录79种生物,大约有82.7％的生物种类是鱼礁区鱼虾的饵料生物(包括35种不带壳和32种带壳的饵料生物),有17.3％的生物种类为非饵料生物。礁区附着生物种类多,附着量大,生长迅速,投礁半年后100％被生物覆盖,附着厚度30mm,附着量达17.487kg/m~2。礁区生物一年四季都能繁殖附着,主要附着期4—10月,高峰期7、8、9三个月,是投礁的最佳时间。     

海洋细菌Pseudomonas putida中具有抗硅藻附着的活性成分

【目的】为发现天然的防污损物质,从分离自海绵Haliclona sp.的细菌Pseudomonas putida中寻找具有抗硅藻附着活性的化合物。【方法】综合菌落生长形态、扫描电镜及16S rDNA序列分析,鉴定细菌种属;采用活性(抗硅藻附着)-化学(薄层色谱、二极管阵列高效液相和核磁共振氢谱)导向法对其中的活性组分进行分离纯化,波谱分析确定结构;采用抗硅藻附着活性模型对单体化合物进行活性复筛。【结果】该细菌鉴定为Pseudomonas putida;从其发酵液中分离得到6个环二肽,分别鉴定为环(亮氨酸-脯氨酸)(1)、环(亮氨酸-丙氨酸)(2)、环(苯丙氨酸-丙氨酸)(3)、环(缬氨酸-酪氨酸)(4)、环(丙氨酸-酪氨酸)(5)、环(丙氨酸-色氨酸)(6);化合物3和6在浓度为50μg/mL时具有明显的抑制硅藻附着活性(抑制率分别为50%和85%)。【结论】海洋细菌Pseudomonas putida中具有抗硅藻附着的活性化合物为环(苯丙氨酸-丙氨酸)和环(丙氨酸-色氨酸)。     

刺参的趋光性以及对附着基颜色的感应行为

为了探讨刺参的趋光特性和附着基颜色对其行为反应的影响,分别用平均趋光率(mean phototactic rate, MPR)和平均聚集率(mean attractive rate, MAR)统计分析了刺参在100、50、10、5和1 lx共5档强度的光照和7种颜色的附着基(红色、灰色、黄色、蓝色、白色、黑色和绿色)下的行为反应差异。结果表明:在水平光场内,光源照度为100、50和10 lx时,光照度较强区与光照度较低区之间的MPR均存在显著差异(P﹤0.05),而光源照度为5和1 lx时,各区域之间的MPR无显著差异;不同颜色附着基实验时,刺参在黑暗和自然光照条件下,同种颜色附着基的MAR无显著差异(P>0.05);在相同光照条件下,黑色和灰色附着基的MAR明显优于其他颜色的附着基,与蓝色、黄色及不放置附着基的MAR差异极显著(P<0.01),不同颜色附着基的MAR由大到小排列为黑色>灰色>红色>绿色>白色>蓝色>黄色。表明刺参的趋光性随着光照强度的增加而减小,呈负趋光性;平均聚集率较高的3种颜色的附着基是黑色、灰色和红色。     

基于附着盘特征量化的眉溪小车轮虫种内研究

研究结合形态学与统计学研究方法,对外寄生于三种不同宿主(鲢、鳙与麦穗鱼)的眉溪小车轮虫Trichodinella myakkae(Mueller, 1937)?rámek-Hu?ek, 1953进行了附着盘特征量化的种内比较研究。研究结果显示:眉溪小车轮虫三种群(鲢种群、鳙种群与麦穗鱼种群)在虫体直径方面的P值为0.136(P>0.05),在附着盘直径、齿环直径和齿体纵长三方面的P值分别为0.009、0.000与0.000(P<0.01);三种群在齿环直径/虫体直径方面的P值为0.000与0.004(P<0.01)。相关性研究结果显示:虫体直径、附着盘直径、齿环直径与齿体纵长两两间均呈显著正相关(P<0.01),缘膜宽与附着盘中其他结构不存在显著相关性(P>0.05)。上述研究结果表明,除虫体直径外,三种群在附着盘直径、齿环直径、齿体纵长,以及齿环直径/虫体直径方面均存在显著差异,其中鲢种群是最大的种群;相关性研究表明,虫体直径主要受附着盘直径的影响,反之亦然;齿环直径主要受齿体纵长的影响,反之亦然;齿体数主要受附着盘大小所影响;缘膜宽则不受附着盘相关结构...     

Vero细胞在微载体上的附着研究

本文着重考查了Vero细胞在几种不同微载体表面的附着情况。发现Vero细胞在Cytode x1微载体系列上附着快于在明胶微载体系列上的附着,试验力求寻得一种更加适合于Vero细胞附着,生长的微载体,实验证明化工自制Ⅰ号微载体与CytodeX1无明显差别,为国产化微载体打下了基础。     

The stress model of abutment tooth and periodontal tissues with unilateral mandibular dissociation and loss by precision extracoronal attachment

In order to explore the application of the precision extracoronal attachment based on three-dimensional finite element stress model in the repair of unilateral mandibular dissociation and loss, the stress distribution of the butment and periodontal tissues when the precision extracoronal attachment was used in unilateral mandibular dissociation and loss was analyzed, so as to provide reference for the application of materials in clinical repair. In this study, the biomechanics of oral cavity and its attachment were analyzed to provide theoretical basis for model construction. Because the degree of periodontal tissue absorption and the number of abutment teeth affected the restoration effect of the coronal precision attachment, the models were established from these two perspectives. The results showed that when the periodontal tissue absorption of both abutment teeth exceeded 1/3, the method of double abutment restoration was not recommended. When three abutments were used, there was a significant decrease compared with the absorption of the periodontal tissue of the double abutment. In clinic, the stress distribution of the distal abutment teeth and its periodontal tissues can be improved by increasing the number of abutment tooth. However, since increasing the number of abutments required an increase in the amount of healthy tooth tissue, it couldn’t be blindly selected in the clinic. After comprehensive consideration, it is appropriate to choose two abutment teeth for restoration.     

Xive种植体周龈下可疑致病菌变化的1年观察

目的研究一年内Xive种植体周常见致病菌的变化情况,为种植体的定期维护提供理论基础。方法临床选取32名种植患者的44枚种植体,记录了修复后1个月,修复后3个月,修复后6个月,修复后12个月四个时段,入选种植牙的菌斑指数（PLI）,牙龈指数（G1）,牙龈出血指数（GBI）,探诊深度（PD）;采用产黑菌、放线菌、具核梭杆菌及厌氧菌的选择性培养基对龈下菌斑标本进行了分离培养。结果随时间延长,种植体周几种龈下菌的检出量除牯放菌外不断增加,1个月到3个月时增加的趋势最为明显,到6个月左右趋于稳定。厌氧菌总数、产黑菌、核梭菌、粘放菌的统计值在1个月和3个月、3个月和6个月比较差异有显著性,但在6个月和12个月比较差异无显著性。各临床指标和X-线指标随时问的变化差异无显著性。结论在临床工作中,应注意加强修复后3个月时种植患者的口腔维护,防止种植体周围炎的发生,提高种植成功率。     

沼蛤(Limnoperna fortunei)幼虫的附着行为特性

沼蛤(Limnoperna fortunei Dunker,1857),俗称淡水壳菜,是一种扩散能力与适应能力都较强的入侵性底栖动物,它对自然环境与输水工程的侵入和大规模附着,不仅会破坏当地的生物群落结构,而且沼蛤成贝在工程内稳定附着后难以去除,造成重大工程危害。通过试验研究沼蛤幼虫的附着行为特性,并利用该特性对原水中的幼虫进行吸引附着处理,以减少幼虫进入工程造成污损附着。选用前期研究推荐的沼蛤幼虫喜好附着的黄麻材料制成的附着排作为试验材料,设置5组附着排长度工况:1,3,5,6,8 m,在5组流量工况:3.1,5.7,6.7,9.6,12.1 L/s下开展试验,研究不同附着排长度和流量条件下沼蛤幼虫的附着行为,以便优选出吸附幼虫的最佳条件。试验结果表明:(1)黄麻材料的吸附效果与附着排长度呈正相关关系,材料长度为3—5m时,吸附率即可达到50%;材料长度为6—8 m时,平均效果为62—76%,最佳吸附率可达93%;(2)流量过大会降低幼虫吸附效果,吸附也更不稳定;(3)幼虫发育先后经历D型幼虫、前期壳顶幼虫、后期壳顶幼虫、踯行期4个时期,吸附材料对后期壳顶和踯行期幼虫的吸附效果较前期壳顶幼虫更好;(4)附着材料密集布置于较短的长度内比稀疏布置于较长的长度内更有利于提高附着效果。     

Impact of nano-topography on bacterial attachment

The adhesion of bacteria to surfaces is an important biological process, but one that has resisted simple categorization due to the number and complexity of parameters involved. The roughness of the substrate is known to play a significant role in the attachment process, particularly when the surface irregularities are comparable to the size of the bacteria and can provide shelter from unfavorable environmental factors. According to this scenario, roughness on a scale much smaller than the bacteria would not be expected to influence the initial attachment. To test this hypothesis, the impact of nanometer-scale roughness on bacterial attachment has been investigated using as-received and chemically etched glass surfaces. The surface modification by etching resulted in a 70% reduction in the nanoscale roughness of the glass surface with no significant alteration of its chemical composition or charge. Nevertheless, the number of bacteria adhering to the etched surface was observed to increase by a factor of three. The increase in attachment was also associated with an alteration in cellular metabolic activity as demonstrated by changes in characteristic cell morphologies and increased production of extracellular polymeric substances. The results indicate that bacteria may be more sensitive to nanoscale surface roughness than was previously believed.     

精准医学与微生物感染——实施精准感染病学的探讨

2015年3月,习近平主席亲自指示科技部召开了国家首次精准医学战略专家座谈会。鉴于我国在病原微生物学、免疫学、疫苗学及感染病学中的成就,本文从病因和机体免疫应答方面分析了我国开展精准感染病学的优势并提出主要切入点。通过对免疫基因组学的研究,结合环境因素及生活习惯的综合研究,将对控制感染性疾病作出创新性贡献,这具有全球性的重要价值。     

Testing attachment point theory: diatom attachment on microtextured polyimide biomimics

Abstract

This paper explores diatom attachment to a range of laser etched polyimide surfaces to directly test ‘attachment point theory’. Static bioassays were conducted on microtextured polyimide surfaces using four diatom species, Fallacia carpentariae, Nitzschia cf. paleacea, Amphora sp. and Navicula jeffreyi with cell sizes ranging from 1 – 14 μm. The microtextured polyimides were modelled from natural fouling resistant bivalve surfaces and had wavelengths above, below and at the same scale as the diatom cell sizes. Diatoms attached in significantly higher numbers to treatments where the numbers of attachment points was highest. The lowest diatom attachment occurred where cells were slightly larger than the microtexture wavelength, resulting in only two theoretical points of attachment. The results support attachment point theory and highlight the need to address larval/cell size in relation to the number of attachment points on a surface. Further studies examining a range of microtexture scales are needed to apply attachment point theory to a suite of fouling organisms and to develop structured surfaces to control the attachment and development of fouling communities.     

Bacterial attachment on optical fibre surfaces

Optical fibres have received considerable attention as high-density sensor arrays suitable for both in vitro and in vivo measurements of biomolecules and biological processes in living organisms and/or nano-environments. The fibre surface was chemically modified by exposure to a selective etchant that preferentially erodes the fibre cores relative to the surrounding cladding material, thus producing a regular pattern of cylindrical wells of approximately 2.5 μm in diameter and 2.5 μm deep. The surface hydrophobicity of the etched and non-etched optical fibres was analysed using the sessile pico-drop method. The surface topography was characterised by atomic force microscopy (AFM), while the surface chemistry was probed by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Six taxonomically different bacterial strains showed a consistent preference for attachment to the nano-scale smoother (R _q = 273 nm), non-etched fibre surfaces (water contact angle, θ = 106° ± 4°). In comparison, the surfaces of the etched optical fibres (water contact angle, θ = 96° ± 10°) were not found to be amenable to bacterial attachment. Bacterial attachment on the non-etched optical fibre substrata varied among different strains.     

藤壶金星幼虫附着变态机制

藤壶属节肢动物门(Arthropoda)甲壳亚门(Crustacea)蔓足下纲(Cirripedia)围胸总目(Thoracica), 具备特殊的形态结构、生活史和种群生态特征,是最主要的海洋污损生物。其幼虫阶段通常经历6期无节幼体和1期不摄食的金星幼虫,从浮游的金星幼虫附着变态成固着的稚体是藤壶生活史中的一个关键环节。外界化学和生物因子中成体提取物、水溶性信息素、足迹、神经递质、激素、生物膜等均影响藤壶金星幼虫的附着变态;内在因子即金星幼虫的生理状态(能量储量和年龄)决定了其对外界因子的反应程度。概括了近年来藤壶附着变态生理机制和分子机制研究的进展,可为深入了解藤壶金星幼虫附着变态机制提供参考,也为开发新型、高效、环保的防污剂提供理论指导。     

Measuring the precision of genetic parameters by a simulation technique

Summary Approximate standard errors of genetic parameter estimates were obtained using a simulation technique and approximation formulae for a simple statistical model. The similarity of the corresponding estimates of standard errors from the two methods indicated that the simulation technique may be useful for estimating the precision of genetic parameter estimates for complex models or unbalanced population structures where approxi mation formulae do not apply. The method of generating simulation populations in the computer is outlined, and a technique of setting approximate confidence limits to heritability estimates is described.     

The growth rate regulates the composition and density of the fibrillar coat on the surface of Streptococcus salivarius K+ cells

Abstract Streptococcus salivarius HB (Lancefield group K) was grown in continuous culture on a chemically defined medium under glucose limitation. The structure and composition of the cell surface was investigated using negative-stain electron microscopy of whole cells and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and rocket immunoelectrophoresis (RIEP) of mutanolysin-solubilized cell-wall fractions. Under most steady-state growth conditions the density of the fibrillar fringe varied from cell to cell, whereas most stationary-phase batch-grown cells exhibited a uniformly dense fibrillar fringe. Varying the generation time at pH 7 over the range from 44 to 560 min profoundly affected both the density of the fibrillar layer and the distribution of specific protein antigens. At intermediate growth rates the fibrillar adhesins AgB and AgC were optimally expressed. At high growth rates the cells were virtually bald and the adhesins were absent from the cell walls. AgD and an unidentified cell wall-associated protein, however, were expressed at all growth rates tested. Slowly growing cells apparently lacked protease-resistant long fibrils but possessed the proteinaceous adhesins.