Er:YAG激光处理对牙釉质及牙本质修复效果的影响

研究不同表面处理条件下Er:YAG激光照射对牙釉质及牙本质修复效果的影响。80个样本随机分成牙釉质和牙本质2大组,再根据处理方式随机分为4小组:①酸蚀(37%磷酸);②Er:YAG激光;③自酸蚀粘接处理剂;④Er:YAG激光+自酸蚀粘接处理剂。与树脂加强型玻璃离子水门汀(RMGIC)粘接后37℃水浴中储存24 h,用万能测试机测定粘接剪切强度。牙釉质及牙本质组结果均为3、4小组粘结强度接近(P0.05),显著高于其他组(P0.05),1、2小组间粘结强度差别无统计学差异(P0.05)。Er:YAG激光照射可替代37%磷酸酸蚀处理方法;G-Bond自酸蚀粘接处理剂可提高牙面与RMGIC间的粘结力,Er:YAG激光处理不影响该效果。     

不同粘接剂在纤维桩修复上前牙残冠残根中的临床疗效比较

目的:比较2种不同的纤维桩粘接剂在桩-核-冠修复方法修复前牙残冠残根的临床疗效.方法:对近2年内的78名96例经过完善根管治疗的上前牙残冠、残根的患者,选用2种不同的粘接材料(3M ESPE RelyX Unicem粘接剂和Panavia F粘接剂)对PD(Produits Dentaires SA)纤维桩进行粘接、3M ESPE Kiltek Z350树脂等材料修复,并经过2年的随访观察,评估2种治疗方法的疗效.结果:经过2年的随访调查发现,96例患牙中仅在半年时出现了1例修复体折断(使用Panavia F粘接法),其余95例均未出现纤维桩的松动、脱落,无根折、桩折现象.结论:纤维桩修复残冠、残根是一种操作简便、省时、临床疗效好的修复方法;3Municem和PanaviaF粘接剂均可以有效防止纤维桩在修复上前牙残冠、残根中的松动、脱落现象,均是有效的粘接手段.     

3M纳米树脂在牙齿修复中的临床效果

目的：分析3M纳米树脂在牙齿修复的临床效果。方法：于2014 年1 月到2014年9 月,选取我院患者90 例,360 颗患牙,随 机分为3M纳米复合树脂组、光固化复合树脂组、玻璃离子水门汀组,观察术后患者的满意度、临床疗效。结果：在术后即时,三组 之间的患者满意度上的差异无统计学意义;在术后1 年后,3M纳米复合树脂组的患者满意度高（89.66 %）于光固化复合树脂组 （78.57 %）和玻璃离子水门汀组（68.97 %）（P<0.05）;在临床疗效方面,3M纳米复合树脂组成功率为93.10%,远高于光固化复合树 脂组（75.00 %）、玻璃离子水门汀组（68.97 %）,组间差异具有统计学意义（P<0.05）;而光固化复合树脂组和玻璃离子水门汀组之 间患者满意度和临床疗效上的差异无统计学意义（P>0.05）。结论：3M纳米树脂治疗在牙齿修复中具有良好的美观性和理想的临 床疗效。     

预酸蚀乳牙牙本质对自酸蚀粘接系统粘接强度的影响

目的:探讨预酸蚀乳牙牙本质对自酸蚀粘接系统粘接强度的影响。方法:随机选取28颗健康乳磨牙,磨除颊舌面釉质,暴露牙本质粘接面,沿近远中向劈开形成56个样本,随机分为7组(n=8)。直接涂布组(A1组,A2组和A3组)分别涂布AdperTM Easy One(AEO),Xeno-V(XV)和OptiBond All In One(AIO)三种自酸蚀粘接剂,预酸蚀组(B1组,B2组和B3组)在涂布三种自酸蚀粘接剂前先使用35%磷酸酸蚀乳牙牙本质15 s,对照组(C组)使用Prime&Bond NTTM(NT)全酸蚀粘接剂,每个样本用Z350复合树脂堆砌成直径为3 mm的树脂小柱,通过剪切试验测试剪切粘接强度,并通过扫描电子显微镜观察断裂表面形态。结果:B1组,B2组的剪切粘接强度值明显高于A1组,A2组(P<0.001);B3组与A3组的剪切粘接强度值比较无明显差别(P=0.94)。A2组的剪切粘接强度值低于C组(P<0.05);B1组的剪切粘接强度值明显高于C组(P<0.001)。扫描电镜观察结果显示各组试件断裂面形态多为牙本质和复合树脂界面破坏。直接涂布组(A1组,A2组和A3组)断裂多发生在混合层的底部,树脂突较少且低于小管口。B1组和B2组试件断裂面可见多数牙本质小管被树脂突填满,断裂多发生在混合层的中上部。B3组试件断裂面可见牙本质小管空虚,树脂突较少。结论:预酸蚀乳牙牙本质可以提高AEO,XV两种自酸蚀粘接剂的剪切粘接强度。自酸蚀粘接剂处理乳牙牙本质可以达到全酸蚀粘接剂处理的粘接强度,但应用自酸蚀粘接剂前预酸蚀乳牙牙本质可以获得更高的粘接强度。     

角倍蚜 Schlechtendalia chinensis(Bell)(Hemiptera:Pemphigidae)各蚜型触角感器的比较分析

本研究利用扫描电镜对角倍蚜各蚜型触角感器的超微结构、类型、分布和数量进行了比较分析。结果表明,角倍蚜的触角上着生4种类型的感器：毛形感器、原生感觉圈、感觉突及次生感觉圈,它们在各蚜型触角上的分布和数量各不相同。其中,毛形感器有TypeⅠ和TypeⅡ两种类型,各蚜型触角上均有分布;原生感觉圈主要分布于干母、无翅干雌、第三代有翅干雌若蚜以及性蚜的触角上,有两种类型：PrⅠ和PrⅡ,分别位于触角的末节和倒数第二节,其中,第三代有翅干雌若蚜的触角上仅存在PrⅠ,无PrⅡ;感觉突仅出现于第三代有翅干雌若蚜触角的第3~5节;次生感觉圈仅存在于有翅型春迁蚜和秋迁蚜触角的第3~5节,其面积约占触角鞭节面积的2/3。我们认为,各蚜型触角感器的差异可能与蚜虫的生境（瘿内或瘿外）、行为（如取食、交配）以及翅的有无（如寄主选择、迁飞等）有关。     

玻璃离子粘固剂——一种新的齿科粘结、修复材料

前言玻璃离子粘固剂(Alumino-Silicate po-lyacrylic cement简称ASPA)是由铝硅酸钙玻璃粉和带羧基的聚丙烯酸水溶液组成。它具有机械强度高、性能稳定、无刺激性、聚合热低、热膨胀系数小,对牙釉质、牙本质及不锈钢有粘结作用,其边缘封闭性好、颜色与天然牙近似等优点,因此,它是一种作为口腔科粘结和修复的多用途新材料。自1971年英国A.D.Wilson和B.E.Kent发明了     

中国甘肃拟蝇虎属一新种(蜘蛛目:跳蛛科)

记述甘肃跳蛛一新种：指状拟蝇虎Plexippoides digitatus sp.nov.。模式标本保存于中国科学院动物研究所,量度单位为mm。指状拟蝇虎Plexippoides digitatus sp.nov.（图1－4）正模♂,1998年7月14日,陈军采自甘肃康县清河林场,标本编号SP98040。鉴别特征新种与盘触拟蝇虎Plexippoides discifer(Schenkel,1953)相似,但有以下区别：1）新种的插入器起始于12点钟位置（图2）,而后者则起始于5点钟位置;2）生殖球的耳状突长,位于9点钟处（图2）,而后者则起如于12：30处;3）跗舟突出明显细长（图3－4）;4）后侧观（图3）肺节突明显大而短,端部宽、中央凹陷,而后者则为指纹。新种的种名取自胫节突的形状。     

三种粘结剂用于纵折牙粘结的微渗漏研究

目的观察三种粘结材料的封闭性能,为折裂牙选择合适的粘结材料提供试验依据。方法选用健康前磨牙30颗,随机分为3组,制备成后牙纵折模型,分别用Clearfil SE Bond／AP—X（A组）、Super—Bond C＆B（B组）,Single Bond／F2000 Cmpomer（C组）进行粘结,在0．5％亚甲基蓝溶液中染色72h后,在电镜下观察染料渗透深度。结果扫描电镜下观察各组标本的粘结界面均有染料渗入,经单因素方差分析,A组与B组、C组有显著性差异,B组与C组之间无显著性差异。结论Clearfil SE Bond的封闭性能优于其它两组,但三种粘结剂均无法避免微渗漏的发生。     

肾缺血预处理对心脏缺血／再灌注损伤的保护作用

目的：探讨肾缺血预处理对家兔心脏缺血／再灌注（I／R）损伤的影响及意义。方法：32只大耳白家兔随机分为假手术（SO）、心脏I／R、经典缺血预处理（CIPC）及肾缺血预处理（RIPC）4组。观察各组心肌梗塞面积、左室舒缩功能、心脏超微结构及心律失常发生率的变化。结果：CIPC、RIPC组,心肌梗塞面积、再灌性心律失常发生率较I／R组明显降低,左室舒缩功能明显恢复（P＜0.01）,心脏超微结构损伤明显减轻。结论：RIPC可诱导出与CIPC类似的心脏保护效应。     

电磁辐射对大鼠内皮祖细胞和肾脏组织学的影响

目的：研究电磁辐射对体外培养骨髓来源的内皮祖细胞（EPCs）增殖、迁移、黏附能力的影响,并探讨其与肾脏疾病的可能关系。方法：密度梯度离心法获取大鼠骨髓单个核细胞（MNCs）,接种至纤维连接素包被的培养板上,培养6d后进行免疫细胞化学和免疫荧光鉴定EPCs。采用MTT比色法、Transwell小室和黏附能力测定实验,观察平均功率密度为65mW/cm2,时间20min的电磁辐射对EPCs的增殖、迁移、黏附能力的影响;同等剂量全身照射大鼠,光镜和透射电镜观察大鼠肾脏组织学和超微结构的变化。结果：从大鼠骨髓能成功分离培养获得EPCs。EPCs的增殖、迁移、黏附能力较对照组显著下降;大鼠接受全身照射后各时相点无明显组织学改变,但超微结构显示在照射后3h后开始出现肾小球毛细血管袢足突肿胀,12h后出现部分足突融合。结论：电磁辐射导致EPCs生物功能显著减弱,肾小球超微结构改变,电磁辐射可能与起肾脏疾病的发生有关。     

Investigation of the mechanism of temperature sensitivity of the electroreceptors of ampullae of lorenzini

In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980.     

Shapes of curves of pH-dependence of reactions

A simple case is considered in which the rate of a two-step reaction depends on pH because the intermediate formed in the first step has to gain (or lose) a proton before it can react in the second step, and in which the rate-determining step therefore changes with pH. The curves of reaction rate against pH are shown to be symmetrical, and the sharpest peak possible has a width at half its height of 1.53pH units, i.e. of 2log(3+2 radical2). Any particular curve for this situation proves to be identical with a curve that could be generated for the pH-dependence of a single-step reaction in which the rate is proportional to the concentration of a particular ionic form of a reactant. Curves for the latter situation, however, can have forms impossible for the former case in which the rate-determining step changes, but only if the protonations that activate and deactivate the reactant are co-operative. The peak can then become even sharper, and its width at half its height can fall to 1.14pH units, i.e. to 2log(2+ radical3).     

Overview of mechanisms of action of lycopene

Dietary intakes of tomatoes and tomato products containing lycopene have been shown to be associated with decreased risk of chronic diseases such as cancer and cardiovascular diseases in numerous studies. Serum and tissue lycopene levels have also been inversely related to the risk of lung and prostate cancers. Lycopene functions as a very potent antioxidant, and this is clearly a major important mechanism of lycopene action. In this regard, lycopene can trap singlet oxygen and reduce mutagenesis in the Ames test. However, evidence is accumulating for other mechanisms as well. Lycopene at physiological concentrations can inhibit human cancer cell growth by interfering with growth factor receptor signaling and cell cycle progression specifically in prostate cancer cells without evidence of toxic effects or apoptosis of cells. Studies using human and animal cells have identified a gene, connexin 43, whose expression is upregulated by lycopene and which allows direct intercellular gap junctional communication (GJC). GJC is deficient in many human tumors and its restoration or upregulation is associated with decreased proliferation. The combination of low concentrations of lycopene with 1,25-dihydroxyvitamin D3 exhibits a synergistic effect on cell proliferation and differentiation and an additive effect on cell cycle progression in the HL-60 promyelocytic leukemia cell line, suggesting some interaction at a nuclear or subcellular level. The combination of lycopene and lutein synergistically interact as antioxidants, and this may relate to specific positioning of different carotenoids in membranes. This review will focus on the growing body of evidence that carotenoids have unexpected biologic effects in experimental systems, some of which may contribute to their cancer preventive properties in models of carcinogenesis. Consideration of solubility in vitro, comparison with doses achieved in humans by dietary means, interactions with other phytochemicals, and other potential mechanisms such as stimulation of xenobiotic metabolism, inhibition of cholesterogenesis, modulation of cyclooxygenase pathways, and inhibition of inflammation will be considered. This review will point out areas for future research where more evidence is needed on the effects of lycopene on the etiology of chronic disease.