两种材料烤瓷冠桥修复后牙周情况长期临床观察

目的：观察两种不同材料烤瓷冠桥修复体对牙周组织的远期影响。方法：对72例患者的224颗牙分别经镍铬合金烤瓷、贵金属烤瓷修复3年后复查,对比观察修复前后牙周组织的的变化,并与邻牙牙周变化情况相比较。结果：有21．2％的镍铬合金烤瓷修复后3年牙龈发生变色,贵金属烤瓷牙龈色泽影响很少或没有;镍铬合金烤瓷和责金属烤瓷修复后牙龈指数、菌斑指数、牙龈出血指数与术前有显著性差异;两种烤瓷冠术前、术后牙周探诊深度无明显差异。结论：贵金属全瓷冠桥修复对牙周组织的影响较少。     

铸造支架联合NITI悬臂梁矫正舌倾下颌磨牙的临床效果评价

目的 评价NITI悬臂梁在矫正舌倾下颌磨牙中的临床效果。方法 选择16例单侧下颌第二磨牙舌倾的病例为研究对象,带垫铸造支架连接双侧下颌后牙,提供颌内支抗、解除咬合锁结,0.018英寸×0.025英寸或0.019英寸×0.025英寸NITI悬臂梁提供颊向旋转力矩和压低力。采用Graphpad Prism 6.0 软件对治疗前、后所测数据进行配对 t 检验。结果 所有患牙均获得直立,牙轴变化24°±1.2°（P<0.01）,近中舌尖到正中矢状面垂直距离变化（3±0.8） mm（P<0.05）,牙周状况良好,咬合关系稳定。结论 铸造支架联合NITI 悬臂梁可提供有效力学机制,矫正舌倾下颌磨牙。     

南京“5.7” 192Ir源放射事故患者的生物剂量估算

目的 用3种方法估算南京"5.7" ¹⁹²Ir源放射事故患者的生物剂量,为核与辐射事故受照者的临床救治提供剂量资料。方法 受照后第5天采集患者外周血,分别进行外周血淋巴细胞染色体"双着丝粒+环"("dic+r")畸变分析、胞质分裂阻滞微核(CBMN)分析、核质桥(NPB +FHC)分析,并估算生物剂量。用双着丝粒畸变在细胞间的泊松分布情况检验照射的均匀性。结果3种方法估算的该患者受到的一次全身等效剂量分别为"dic+r"畸变分析1.51 Gy (95% CI 1.40~1.61),CBMN 分析1.47 Gy (95% CI 1.36~1.60),NPB+FHC分析1.30 Gy(95% CI 1.00~1.60)。泊松分布检验结果显示,该患者"dic+r"畸变偏离泊松分布,受到了不均匀照射。结论 外周血淋巴细胞染色体"dic+r"畸变分析、CBMN分析、NPB+FHC分析均是有效的生物剂量估算手段,对本例急性局部不均匀照射患者估算的一次全身等效剂量与临床诊断结果相符。     

两种义齿修复下颌单侧游离端缺失基牙及缺牙区牙槽嵴应力分布的比较

目的：分析两种不同结构义齿修复单侧游离端缺失时基牙及缺牙区牙槽嵴应力分布特点,为临床义齿选择提供依据。 方法：应用三维有限元方法分别测定并比较应用键槽缓冲式附着体义齿和单端固定桥义齿修复单侧游离端缺失时基牙及缺牙区牙槽嵴应力分布情况。结果: 键槽缓冲式附着体义齿基牙牙根应力峰值(1.42E+5)MPa,基牙牙周膜应力峰值(1.33E+4)MPa,缺牙区牙槽嵴应力峰值(3.49E+5)MPa。单端固定桥义齿基牙牙根应力峰值(1.45E+7)MPa,基牙牙周膜应力峰值(2.25E+6)MPa,缺牙区牙槽嵴应力峰值(1.45E+3)MPa。两种义齿基牙应力峰值均在根中、上1/3及颈部。结论:在游离端缺失修复时, 键槽缓冲式附着体义齿可减少基牙负荷,但牙槽嵴条件要好,两种义齿修复均要注意牙槽嵴健康。     

Single-chip mechatronic microsystem for surface imaging and force response studies

We report on a stand-alone single-chip (7 x 10 mm) atomic force microscopy unit including a fully integrated array of cantilevers, each of which has an individual actuation, detection, and control unit so that standard atomic force microscopy operations can be performed by means of the chip only without any external controller. The system offers drastically reduced overall size and costs as well as increased scanning speed and can be fabricated with standard complementary metal oxide semiconductor technology with some subsequent micromachining steps to form the cantilevers. Full integration of microelectronic and micromechanical components on the same chip allows for the controlling and monitoring of all system functions. The on-chip circuitry, which includes analog signal amplification and filtering stages with offset compensation, analog-to-digital converters, a powerful digital signal processor, and an on-chip digital interface for data transmission, notably improves the overall system performance. The microsystem characterization evidenced a vertical resolution of < 1 nm and a force resolution of < 1 nN as shown in the measurement results. The monolithic system represents a paradigm of a mechatronic microsystem that allows for precise and fully controlled mechanical manipulation in the nanoworld.     

心肌桥对急性ST段抬高型心肌梗死影响的研究

目的探讨心肌桥对急性ST段抬高型心肌梗死(STEMI)发病及预后的可能影响。方法顺序入选2010年1月~2014年2月北京大学人民医院因STEMI急诊行冠状动脉诊疗手术患者,收集临床资料和影像学资料。(1)探讨心肌桥对心肌梗死发生的影响:选取前降支罪犯血管STEMI患者为观察组,同期无心肌梗死(MI)病史的前降支存在病变患者为对照组,分析STEMI的危险因素;(2)探讨心肌桥对STEMI预后的影响:根据前降支罪犯血管患者住院期间有无主要不良心脏事件(MACE),将患者分为MACE组和无MACE组,判断心肌桥对心肌梗死预后的影响。结果 (1)STEMI患者中,心肌桥的检出率高于同期择期冠状动脉诊疗患者(34.5%vs 11.8%,P0.05);(2)对前降支罪犯血管的STEMI发生的危险因素进行分析,发现男性(OR 1.816,95%CI 1.227-2.688,P=0.003)、LDL-C升高(OR 2.363,95%CI 1.929-2.894,P=0.000)和心肌桥(OR2.704,95%CI 1.749-4.181,P=0.000)是STEMI发生的独立危险因素;(3)对前降支罪犯血管STEMI患者分析发现,心肌桥与住院期间MACE无关(P0.05)。结论 STEMI患者心肌桥检出率较高,前降支心肌桥是STEMI发生的独立危险因素。发生STEMI患者中,血流开通后罪犯血管的心肌桥对住院期间MACE无影响。     

红、白肌纤维为肌桥缝接狗神经缺损的实验形态学研究

分别用红、白肌纤维为肌桥,桥接狗股神经和正中神经缺损3cm。术后10个月切取桥接神经,并将它分成神经近段(正常神经部位)、肌桥段、神经远段(再生神经部位)和远、近端缝合段5个部分。常规制成光、电镜标本,最后镜下观察和LUZEX-F图像分析仪测定神经远、近段内有髓神经纤维密度和数量等。结果显示,红肌纤维为主的肌桥明显较白肌纤维的神经再生效果好(P<0.05)。特别是缝匠肌尾侧部为肌桥(红肌纤维为主)更明显较其颅侧部(白肌纤维为主)的神经纤维再生数量多(P<0.05)。由此可知缝匠肌尾侧部是一个最适宜神经再生的肌肉。     

Organic interlamellar layers,mesolayers and mineral nanobridges: Contribution to strength in abalone (Haliotis rufescence) nacre

The contributions of mesolayers, organic interlamellar layers and nanoasperities/mineral bridges to the strength of nacre from red abalone (Haliotis rufescens) shell nacre are investigated. Samples were demineralized and deproteinized to separate the organic and mineral components, respectively. Tensile tests were performed on both the isolated organic constituent and the isolated mineral. The strength of the isolated organic component suggests that growth bands play an important role in the mechanical behavior as they are thick regions of protein that are a significant fraction (∼0.4) of the total organic content. The thickness variation of the nacre tablets was measured and found to be a small fraction of the mean tablet thickness (0.568 μm); the standard deviation is 26 nm, indicating that the wedge mechanism of toughening does not operate in the nacre investigated. Results obtained from the isolated mineral validate the importance of the organic constituent as the mechanical properties decline greatly when the organic component is removed. The results presented herein add to the understanding of the mechanical response of the organic interlayers and growth bands and their effect on the toughness of the abalone nacre.