Significance of the Dermal Route of Exposure to Risk Assessment

The skin is a route of exposure that needs to be considered when conducting a risk assessment. It is necessary to identify the potential for dermal penetration by a chemical as well as to determine the overall importance of the dermal route of exposure as compared with inhalation or oral routes of exposure. The physical state of the chemical, vapor or liquid, the concentration, neat or dilute, and the vehicle, lipid or aqueous, is also important. Dermal risk is related to the product of the amounts of penetration and toxicity. Toxicity involves local effects on the skin itself and the potential for systemic effects. Dermal penetration is described in large part by the permeability constant. When permeability constants are not known, partition coefficients can be used to estimate a chemical's potential to permeate the skin. With these concepts in mind, a tiered approach is proposed for dermal risk assessment. A key first step is the determination of a skin-to-air or skin-to-medium partition coefficient to estimate a potential for dermal absorption. Building a physiologically-based pharmacokinetic (PBPK) model is another step in the tiered approach and is useful prior to classical in vivo toxicity tests. A PBPK model can be used to determine a permeability constant for a chemical as well as to show the distribution of the chemical systemically. A detailed understanding of species differences in the structure and function of the skin and how they relate to differences in penetration rates is necessary in order to extrapolate animal data from PBPK models to the human. A study is in progress to examine anatomical differences for four species.     

Sensing the skin: acne sufferers and the dermatologization of life

ABSTRACT

In this paper, we explore what we call the “dermatologization of life” and how it regulates the ways in which acne sufferers relate to their skin. We refer to these ways of relating to the skin as “skin sensing”. Through an analysis of the online narratives found on the website acne.org, we demonstrate how the skin sensing bound up with dermatologization both converges with and diverges from biomedical understandings of acne in three key contexts: the hormonal, the alimentary and the nocturnal. In doing so, we show that skin sensing involves a complex combination of pleasure and pain, excitement and exhaustion, and work and play. Ultimately, we suggest that the ways in which acne sufferers sense their skin open up a set of possibilities that not only disable but also enable them as they embark on the often all-consuming quest for a clear complexion.     

一曲加拿大普通建设者的颂歌

加拿大作家迈克尔·翁达杰的小说(披上一块狮子皮》用历史的眼光从多民族移民的角度展现了加拿大人独特的自我意识。与他的另一小说《英国病人》相比,《披上一块狮子皮》同样具有史诗般恢宏的气势,并以细腻的笔触描绘了加拿大无名建设者们生活中的酸甜苦辣,从历史的角度阐述了移民、语言、身份等后殖民理论颇为关注的问题。     

新型氮支套索冠醚的合成及络合阳离子的电导特征

以苯氧乙醇为起始剂合成了两种新型氮支套索冠醚:N-苯氧乙基单氮杂-18-冠-6(18CE)与N-苯氧乙基单氮杂-15-冠-5(15CE).通过红外光谱、核磁共振氢谱、紫外光谱和元素分析表征了新冠醚及其中间体的结构.测试了18CE与15CE络合阳离子对溶液电导率的影响.     

Nonparametric Comparison for Multivariate Panel Count Data

Multivariate panel count data often occur when there exist several related recurrent events or response variables defined by occurrences of related events. For univariate panel count data, several nonparametric treatment comparison procedures have been developed. However, it does not seem to exist a nonparametric procedure for multivariate cases. Based on differences between estimated mean functions, this article proposes a class of nonparametric test procedures for multivariate panel count data. The asymptotic distribution of the new test statistics is established and a simulation study is conducted. Moreover, the new procedures are applied to a skin cancer problem that motivated this study.     

水陆兼行的特色运输——近代甘宁青回族羊毛贸易的运输网络

交通运输是区域社会、经济发展的主动脉。鸦片战争以来,中国自东南沿海到西北内陆先后被卷入世界资本主义市场体系之中,随着资本主义经济势力的入侵,地处内陆的甘宁青地区的羊毛等畜牧业产品也成资本主义国家掠夺的工业原料,开始大量出口,为了能把当地所产羊毛等畜牧业产品运出所在地区,甘宁青的回族羊毛运输商们选择了两种独具特色的运输工...     

考虑井筒储存和表皮效应的变流率问题的精确解

本文用较新的观点，建立了无限大均质地层(考虑井筒储存和表皮效应)中单井系统变流率问题的压力降分布的数学模型，利用Laplace变换法，解出了井底压力变化的精确解析解;并将其无因次化，以便于在实际中用来制作试井分析样板曲线图，并简要地指出了实际应用此精确解的方法。     

The Idealization of Light Skin as Vehicle of Social Pathogen vis-à-vis Bleaching Syndrome: Implications of Globalization for Human Behavior

Globalization is manifested via idealization of light skin. On the basis of light skin as worldwide physiological ideal there evolved a prerequisite to enhanced quality of life. The result precipitated the bleaching syndrome as social pathogen among people of color. Western social work academies have been less privy as a result of its disqualification from public discourse. To educate social workers globally will require an acknowledgement of bleaching syndrome. In the aftermath of being informed, people of color and the Western social workers who serve them will move the profession to its next level of service technology.     

Skin color,sex, and educational attainment in the post-civil rights era

We assess the relationship between skin color and educational attainment for native-born non-Hispanic Black and White men and women, using data from the Coronary Artery Risk Development in Young Adults (CARDIA) Study. CARDIA is a medical cohort study with twenty years of social background data and a continuous measure of skin color, recorded as the percent of light reflected off skin. For Black men and women, we find a one-standard-deviation increase in skin lightness to be associated with a quarter-year increase in educational attainment. For White women, we find an association approximately equal in magnitude to that found for Black respondents, and the pattern of significance across educational transitions suggests that skin color for White women is not simply a proxy for family background. For White men, any relationship between skin color and attainment is not robust and, analyses suggest, might primarily reflect differences in family background. Findings suggest that discrimination on the basis of skin color may be less specific to race than previously thought.     

Lognormal Distributions for Skin Area as a Function of Body Weight1

This paper reanalyzes the dataset cited by the U.S. Environmental Protection Agency in its Exposure Factors Handbook that contains measurements of skin area, height, and body weight for 401 people spanning all stages of development. The reanalysis shows that a univariate model for total skin area as a function of body weight gives useful and practical results with little or no loss of reliability as compared to the Agency's bivariate model. This new result leads to a new method to develop Lognormal distributions for total skin area as a function of body weight alone.