可摘局部义齿适合性方法的评价

目的: 评价可摘局部义齿(removable partial denture, RPD)适合性的三种方法的异同及适应证。方法: 在下颌牙列缺损石膏模型上制作RPD,用硅橡胶印模材复制RPD与模型表面的间隙形成硅橡胶薄膜样本。在RPD各组件处的薄膜样本上,用硅橡胶膜切片测量法并选择不同数量的测量点测量获得薄膜平均厚度,再用单因素方差分析和独立样本t检验比较基托、大连接体、牙合支托处测量点数量不同对测量结果的影响。采用硅橡胶膜切片测量法、石膏模型三维分析法和翻制模型三维分析法测量RPD各组件处硅橡胶薄膜的厚度,用单因素方差分析比较三种方法的测量结果差异是否有统计学意义。结果: 硅橡胶膜切片测量法选取测量点数量不同测得的基托和大连接体处硅橡胶薄膜的平均厚度差异有统计学意义(P<0.05),牙合支托处硅橡胶薄膜的平均厚度差异无统计学意义(P>0.05)。三种评价方法测得的RPD各组件和总体的硅橡胶薄膜厚度差异均有统计学意义(P<0.01),多重比较表明,石膏模型三维分析法和翻制模型三维分析法的测量结果较硅橡胶膜切片测量法的薄(P<0.05),石膏模型三维分析法和翻制模型三维分析法测量的硅橡胶薄膜厚度差异无统计学意义(P>0.05)。结论: 硅橡胶膜切片测量法的测量结果受测量点数量影响,其测量结果可靠性较差;石膏模型三维分析法、翻制模型三维分析法较硅橡胶膜切片测量法能更全面、有效地评价RPD的适合性,石膏模型三维分析法适用于体外评价,翻制模型三维分析法适用于体内评价。     

Mediation Effect of Physical Activity on Obesity in Black Women

Background and objective

Sociodemographic and lifestyle factors, physical activity, diet, and nutrients are important in the understanding of obesity. The possibly direct or indirect nature of the associations among these factors and the eventual link to obesity is not well understood. In this study, we assess the indirect association between socio-demographic factors and obesity.

Comparison of two quantitative fit-test methods using N95 filtering facepiece respirators

Current regulations require annual fit testing before an employee can wear a respirator during work activities. The goal of this research is to determine whether respirator fit measured with two TSI Portacount instruments simultaneously sampling ambient particle concentrations inside and outside of the respirator facepiece is similar to fit measured during an ambient aerosol condensation nuclei counter quantitative fit test.

Sixteen subjects (ten female; six male) were recruited for a range of facial sizes. Each subject donned an N95 filtering facepiece respirator, completed two fit tests in random order (ambient aerosol condensation nuclei counter quantitative fit test and two-instrument real-time fit test) without removing or adjusting the respirator between tests. Fit tests were compared using Spearman's rank correlation coefficients.

The real-time two-instrument method fit factors were similar to those measured with the single-instrument quantitative fit test. The first four exercises were highly correlated (r > 0.7) between the two protocols. Respirator fit was altered during the talking or grimace exercise, both of which involve facial movements that could dislodge the facepiece.

Our analyses suggest that the new real-time two-instrument methodology can be used in future studies to evaluate fit before and during work activities.     

Statistical analysis of the behavior of fracture toughness of compound bioceramic artificial bone

We show the manufacturing procedure of the test specimen of the compound bioceramic artificial bone, conduct experiments to measure its fracture toughness, and conclude that the experiment data conform to the two-parameter Weibull distribution with scale parameter β = 0.527369 and form parameter α = 5.24317. Furthermore, compound bioceramic artificial bone is of a high level of crack sensitivity and its data for the fracture toughness is has a high dispersion. We also analyze the evolution of the confidence level of the reliability of its fracture toughness. With the increase of the confidence level γ, the crack sensitivity increases, but the median, the discreteness, and the confidence intervals decrease. The size of the test specimen influences the experiment for the fracture toughness, the measured values and their dispersion, and there exists the conversion between size of the test specimen and that of the real device. We extend the results to introduce the statistic model of the size effect of the fracture toughness.     

A three-dimensional object orientation detector assisting people with developmental disabilities to control their environmental stimulation through simple occupational activities with a Nintendo Wii Remote Controller

This study evaluated whether two people with developmental disabilities would be able to actively perform simple occupational activities to control their preferred environmental stimulation using a Nintendo Wii Remote Controller with a newly developed three-dimensional object orientation detection program (TDOODP, i.e. a new software program, which turns a Wii Remote Controller into a three-dimensional object orientation detector). An ABAB design, in which A represented the baseline and B represented intervention phases, was adopted in this study. The data shows that the performance of both participants has significantly increased (i.e. they perform more simple occupational activities to activate the control system to produce environmental stimulation) during the intervention phases. The practical and developmental implications of the findings are discussed.     

包载甲氨蝶呤的聚乙交酯丙交酯纳米颗粒的制备与体外释药机制研究

目的 制备包载甲氨蝶呤(MTX)的聚乙交酯丙交酯(PLGA)纳米颗粒并研究体外释药机制.方法 采用溶剂挥发法制备包载MTX的PLGA纳米颗粒,对其形貌、大小进行表征,测定体外释药曲线,并采用药学模型进行拟合.结果 纳米颗粒平均粒径为175.9nm,具有明显的缓释作用,释药行为最符合双相动力学方程.结论 该研究为开发MTX的新剂型提供了实验依据.     

种植义齿部件松动的实验研究Ⅲ基台与修复体适合性的实验研究

目的：研究修复体不同制作方法对种植义齿部件适合性的影响。方法：采用滴蜡铸造法、预成塑料修复帽铸法及计算机控制电火花加工法制作金属修复体并回位到基台上，按纵、横断面剖开，在SEM下观察并测量修复体与基台之间的适合性。结果：滴蜡铸造法所制作的修复何等适合性差，就位率低；预成塑料修复帽铸造法制作的修复体适合性较好，但就位率低；计算机控制电火花加工法制作的修复体适合性好，就位率高。结论：计算机控制下电火花加工法系种植义齿金属修复体制作的最佳方法。     

肝循环门静脉系统的压力—流量关系

本文对兔离体肝脏的门静脉系统在门静脉狭窄、肝内阻塞、肝动脉压改变及对照状态下进行了血液动力学方面的动态测量和分析。得到肝脏门静脉系统的压力—流量曲线,通过回归分析,确定其回归方程为Q=a blnP。经数理统计,找出生理及各种病理模拟状态下具有显著性差异的指标b:在不同程度门静脉狭窄及不同程度肝内阻塞时,组内及各状态之间参数b的均数均有显著差异(P<0.01),在不同的肝动脉压状态下,参数b的均数在组内同样有显著差异(P<0.01)。     

Nonlinear three-dimensional finite element analysis of newly designed cementless total hip stems

We designed 2 new types of proximally coated stems (the FMS and FMS-anatomic) based on the endosteal geometry of femora with congenital dislocation or dysplastic hip. The FMS was symmetric while the FMS-anatomic was asymmetric. We compared the proximal fit and fill to the femoral canal, contact stress, relative motion, and load transfer to the femur of 5 stems (FMS, FMS-anatomic, Omnifit, Omniflex, and individual stem) using three-dimensional computer simulation and finite element analysis. The FMS and FMS-anatomic showed a significantly greater fit and fill than conventional stems. The dispersion of the contact stresses and reduction of relative motions in the proximal area were the best in the FMS-anatomic compared to other stems with the exception of the individual stem. In addition, the FMS-anatomic stem transferred most of the load to the proximal femur. Our results suggest that the FMS-anatomic should provide better biomechanical stability at least in the early postoperative period.