Color Stability of Dry Earth Pigmented Maxillofacial Silicone A-2186 Subjected to Microwave Energy Exposure

PURPOSE: The purpose of this study was to measure spectrophotometrically the color stability of pigmented A-2186 silicone maxillofacial elastomer with 10% by volume of titanium white dry earth opacifier before and after exposure to microwave energy over a simulated 1.5-year period of microwave sterilization. Materials AND METHODS: A-2186 silicone elastomer opacified with titanium white dry earth pigment, pigmented with 5 cosmetic dry earth pigment colors [no pigment (control) group (Pc), red (Pr), yellow ochre (Py), burnt sienna (Po), and a mixture of Pr + Py + Po color group (P3)], was used in this study. Each of the 5 experimental groups consisted of 5 specimens. All specimens were placed in a 250 ml glass beaker filled with 150 ml of water (replenished for each microwave exposure). An exposure of 6 minutes was used 18 times (simulating 1.5 years of microwave sterilization with one 6 minute exposure monthly). Reflectance values were measured by spectrophotometer. Three- and two-way analyses of variance with repeated measures were performed for the color difference (DeltaE*) with the factors of group/color/months, and group/months, respectively. Means were compared by Tukey Honest Significant Difference (HSD) multiple range test calculated at the 0.05 level of significance using SPSS. RESULTS: The trained human eye can detect color changes (DeltaE*) greater than 1.0. Most DeltaE* values of the red pigment group at all intervals and the mixed pigment group at 15- and 18- month intervals increased significantly greater than 1.0 (p < 0.001) compared with the control group. Yellow and burnt sienna groups remained the most color stable over time with DeltaE* values below 0.35. CONCLUSIONS: Lack of color stability of red dry earth pigmented A-2186 silicone maxillofacial elastomers was clinically significant after 12-month exposure to microwave energy as compared with yellow, burnt sienna, and opacified A-2186 dry earth pigments.     

某儿童医院10年临床报告细菌性痢疾的流行病学特征

目的探讨细菌性痢疾(以下简称菌痢)近10年流行特点。方法对10年来收集的全院各科上报的菌痢进行回顾性分析。结果1993-2002年报告菌痢10861例,占传染病报告总数的62.92%,传染科门诊量占全院门诊百分比的年变化为8.54%～4.33%;菌痢发病占传染科门诊的年比率变化为1.05%～3.45%;<1岁、1～3岁、4～6岁、7～9岁、≥10岁5个年龄组,各组之间菌痢检出率差异有统计学意义,1～3岁组检出率最高;细菌性痢疾每年4月检出率开始上升,8月达最高,11月检出率恢复到上升前水平;不同性别的儿童检出率差异有统计学意义,男童明显高于女童。结论细菌性痢疾检出年龄特点为婴幼儿最高,随年龄增长,发病逐渐减少;发病高峰季节向春秋季扩展。     

Influence on binding of third-order torque to second-order angulation

Using an earlier model, which described the critical contact angle for binding from second-order angulation alone, a more generalized model is derived that combines the effects of angulation and torque. From this vantage point, the onset of binding is evaluated for 3 scenarios: second-order angulation alone, third-order torque only, and a combination of second-order angulation and third-order torque. These scenarios are detailed by plotting the critical contact angle for binding against the torque angle as a function of 10 wire dimensions (16 x 16, 16 x 22, 17 x 17, 17 x 22, 17 x 25, 18 x 18, 18 x 22, 18 x 25, 19 x 25, and 21 x 25 mil), 4 bracket widths (70, 100, 130, and 160 mil), and 4 bracket slots (18, 20.5, 22, and 24.5 mil). From these plots, we learn that each wire base dimension (eg, an 18-mil base as found in 18 x 18-mil, 18 x 22-mil and 18 x 25-mil archwires) has a common maximum critical contact angle for binding. Moreover, each wire-slot combination has a common maximum torque angle, which is independent of bracket width. Finally, we learn that archwire-bracket combinations that use a metric 0.5-mm slot might have some advantages with regard to torquing--given the current philosophy that light, continuous forces are more favorable.     

宫腔镜在辅助生殖技术中的应用

目的：探讨宫腔镜检查术在辅助生殖技术中应用的重要性。方法：对150例拟行辅助生殖技术的不育妇女行常规宫腔镜检查。结果：宫腔镜150例中47例（31％）有镜下异常，其中：子宫内膜息肉或息肉样增生18例（12％），子宫内膜单纯性增生17例（11％），子宫畸形7例（5％），宫腔粘连狭窄3例（2％），子宫内膜结核1例（0．7％），子宫黏膜下肌瘤或腺肌瘤1例（0．7％）。以宫腔镜诊断为标准，阴道超声诊断敏感性、特异性、阳性预测值、阴性预测值、准确率分别为66％（31／47）、98％（101／103）、94％（31／33）、86％（101／117）、88％（132／150），子宫造影分别为26％（12／47）、100％（95／95）、100％（12／12）、73％（95／130）、75％（107／142）。结论：宫腔镜检查术具有良好的可接受性和准确性，应作为辅助生殖技术前的常规检查。