Prenatal diagnosis for Epidermolysis bullosa: a study of 144 consecutive pregnancies at risk

Epidermolysis bullosa (EB) is a group of inherited disorders characterized by increased skin fragility, resulting in blisters and erosions after minor trauma. Mutations in 10 structural genes expressed in the cutaneous basement membrane zone have been reported. The DebRA Molecular Diagnostics Laboratory at Jefferson Medical College has performed 144 DNA-based prenatal diagnoses since 1993 in families at risk for recurrence of the most severe forms of EB, including the recessive dystrophic EB (RDEB), junctional EB (JEB), EB with pyloric atresia (EB-PA), and EB simplex (EBS). A mutation-detection strategy using either conformation-sensitive gel electrophoresis (CSGE) or denaturing high-performance liquid chromatography (dHPLC) scanning analysis, followed by nucleotide sequencing, was applied to most cases with DEB and to all JEB, EB-PA, and EBS families. For some RDEB families, linkage analysis was performed, either alone when the inheritance pattern was clear or in combination with one mutation. Among the 144 prenatal diagnoses, 63 were for RDEB, 69 for JEB, 6 for EB-PA, and 6 for EBS. Twenty-eight normal, 73 heterozygous carrier, and 28 affected RDEB, JEB, and EB-PA pregnancies were reported in these recessively inherited diseases. Two affected and four normal pregnancies were predicted in dominantly inherited EBS. Among the 144 pregnancies, 9 were terminated without confirmation, 13 cases were lost to follow-up, and 6 pregnancies are ongoing. There were 6 families with inconclusive results due either to recombination events between flanking markers, absence of informative markers for one allele, or lack of sample from the previously affected child. There were three discordant results, one that was explained by maternal contamination of the chorionic villus sample and two that were unresolved. Overall, the availability, relative ease, and over 98% success rate make molecular DNA-based prenatal diagnosis a viable option for EB families at risk. Copyright © 2003 John Wiley & Sons, Ltd.     

A simple method for estimating dermal absorption of chemicals in water

A semiempirical mathematical model is proposed for estimating the dermal absorption of chemicals from dilute aqueous solutions, such as bath water. Absorption depends on the concentration of the chemical in water, the area of skin exposed, the time of exposure, and a permeation coefficient that depends importantly on the relative solubility of the material in lipids and water, among other factors not so easily modeled.     

野外极端低温环境人体皮肤温度变化研究

为明确不同极端低温环境与防护装备下,日间清醒和夜间睡眠状态下各部位皮肤温度变化特征,在-16 ℃～-30 ℃极端低温环境下,采用皮温测量系统对实验对象5个代表性部位（胸部、手臂、大腿、小腿和脚趾）皮肤温度进行测试。结果表明:日间测试胸部温度相对最高,大腿和小腿在实验中后期出现温度反转。夜间除脚趾外,各部位皮肤温度变化差异较小,大腿温度相对最高,小腿温度与其他部位分离。研究结果可为低温环境下防护服研发与保暖效果评价提供参考。     

基于三维“O”型圈的采空区多场分布特征数值模拟

为进一步研究综放采空区的多场分布特征,以大兴矿N2-706工作面为例,构建"双三"模型,即优化三维"O"型圈采空区冒落非均质多孔介质数学模型及"U"型通风方式下的三维综放采空区物理模型,重点考虑了采空区垂直方向上的孔隙率变化,并实现了孔隙率的三维可视化。运用Fluent软件加载自定义UDF对采空区气体压力分布、漏风场及氧气、瓦斯分布情况进行了数值模拟,得出与实际情况相吻合的采空区气体压力分布、合理漏风量范围内的风流场分布,其中重点分析瓦斯体积分数分布规律。结果表明:考虑三维孔隙率的数值模拟结果收敛性更好,采空区瓦斯的积聚现象不仅出现在采空区顶部,在距底板20~25 m高度的位置就大量上浮,且呈现高体积分数瓦斯积聚分布的特征规律。     

单面受火的方中空夹层钢管混凝土短柱耐火极限

为研究单面受火的方中空夹层钢管混凝土短柱耐火极限,在合理选择材料本构关系和边界条件的基础上,利用ABAQUS软件建立了高温下方中空夹层钢管混凝土短柱温度场和力学场分析模型,通过与试验数据对比验证,结果吻合良好。基于此模型,对不同的混凝土强度、钢管强度、内钢管厚度、空心率、荷载比进行耐火极限参数分析,并定量给出计算此类构件耐火极限的简化公式。研究结果表明:荷载比是构件耐火极限的主要影响参数。荷载比越大,构件的耐火极限越小。     

大气气溶胶粒子质量浓度分布规律研究

在可吸入性颗粒物粒径范围内(d_p<10μm),上海市区大气中气溶胶粒子质量浓度分布为双峰型,峰值出现在1.0μm左右(积聚模态粒子区)和4.5μm左右(粗粒子区),且呈现大粒径处峰值大于小粒径处峰值的趋势。与质量浓度分布曲线相似,质量概率密度分布也为双峰型,峰值出现在0.8μm左右和4.0μm左右。模拟结果表明,上海市区大气中气溶胶粒子质量概率密度分布规律符合双重分布函数:y=exp[-(a_4d~4 a_3d~3 a_2d~2 a_1d a_0)],所表征的类型,应用双重分布函数能解释大气气溶胶粒子的分布规律。     

Skin reactions to latex in dental professionals – first Croatian data

Purpose. To determine the prevalence of undesirable skin reactions to latex in dental professionals and students of the School of Dental Medicine in Zagreb, Croatia. Methods. Our research included 444 participants, of which 200 agreed to undergo a skin prick test (SPT). All participants answered a questionnaire in which we asked about incidence of skin lesions, duration of occupational exposure to latex, localization of skin lesions and symptoms. Statistical analysis of the questionnaire and test results was then carried out. Results. Of the total 444 participants surveyed, 249 (56.1%) reported lesions on their skin (professionals 64.8%, students 6.1–58.5%). From the questionnaire, 239 (96.0%) respondents reported lesions on the hands and fingers, mostly in the form of erythema (37.0%) and occasional dryness of skin (29.0%). Positive SPT results were found in 14 (7.0%) out of the 200 respondents who underwent the test. Conclusions. While a large number of subjects (56.1%) reported skin lesions when using latex products at their workplace, the SPT test was positive only in 7.0%. The results show that the prevalence of self-reported skin lesions was significantly related to the length of occupational exposure, with a substantial effect size (p?<?0.001; V?=?0.334).     

低成本轻质复合蒙布在飞艇尾翼中的应用

目的研究一种低成本轻质复合蒙布设计,为中小型飞艇尾翼提供蒙皮材料。方法通过材料选型、连接设计、典型的复合蒙布性能测试。结果实现了该型蒙布在某大型飞艇尾翼中的应用,表现出了良好的力学性能、可靠性与维修性。结论结构质量与同等强度的气囊材料相比约轻30%。同时,该型复合蒙布还可用于飞艇框架结构的装饰,具有较高的使用价值。     

“Hypersensitivity to Electricity” in the Office; Symptoms and Improvement

Nineteen persons “hypersensitive” to electricity and 20 nonafflicted persons were studied for 1 ½ years. The most discernible hypersensitivity symptoms were pricking sensations and redness in the face, but these symptoms were present in only half of the afflicted. Other symptoms were similar to symptoms experienced during office work and this study does not support the idea that electrosensitivity is one single syndrome. The “hypersensitive” persons improved significantly, mainly on neuropsychiatric symptoms, but the skin problems sustained— as did the belief about their cause. The afflicted persons used less conventional medication than the group of the nonafflicted, which suggests a general tendency for attribution to environmental factors.     

双回路热解炉垃圾焚烧NOx排放特性研究

本文利用双回路立式热解焚烧炉对某地区的垃圾进行试验研究,通过调节过量空气系数,一、二次风机的风量等参数,研究双回路热解炉垃圾焚烧NOx排放特性.结果表明：焚烧炉的二燃室温度能够达到850℃,烟气停留时间超过2秒,燃烧灰的热灼减率小于3％.随着引风机风量系数的增加,烟气中NOx的含量先增加后减少;二燃室的温度先升高后降低.