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172 May, 1970 Tensile Characteristics of Human Hair and Some Effects of Hair Spray DAVID G. WELTON, M.D. and WALTER E. NOREM, PhD. For centuries man has been concerned with the appearance (and disappearance) of the hair on his head. In order to enhance his general appearance and to keep up with the ever-changing styles, man has subjected his hair to brushing, combing, washing, rinsing, drying, curling, teasing, and straightening, and to the application of tints, dyes, oils, powders, sprays, and many other chemical preparations. Some of these treatments may alter physical characteristics of hair—such as its breaking strength, ductility (extensibility), or toughness, and thereby may play a role in certain disorders of the hair and scalp. While there are numerous reports in the engineering and other technical literature about measurements of various physical characteristics of hair and its mechanical behavior under stress, there are few such reports in the medical literature of the last 15 years. An exception is Price and Menafee's recent report that dimethyl sulfoxide in concentrations of about 80% produced a marked increase in the stress relaxation of human hair.1 Presented herein are (1) a brief review of the structure of human hair: (2) a description of the chemical composition and properties of hair sprays; (3) a discussion of the tensile properties of engineering materials; and (4) a report of an experimental procedure in which tensile characteristics of normal hair were studied before and after the application of hair spray. Structure of Hair A human hair may be visualized as a complex fiber composed (Fig. 1.) of a thin, outer layer, its "cuticle," then a cylindrical Read in part befpre the American Dermato logical Association, Dorado Beach, Puerto Rico, April 6, 1968. ♦Dr. Welton is in private practice in Charlotte, and is Clinical Associate, Department of Dermatology, Duke University Medical Center. ♦♦Dr. Norem is Associate Professor of Engineering Materials, Universityof North Carolina at Charlotte. Reprint requests to 1012 South Kings Drive, Charlotte, N. C. 28207 (Dr. Welton). mass of fibrils or "cortical cells," and an inner core or "medulla."2 A diagrammatic representation at various levels of magnification is shown in Figure 2.3 Editorial comment on page 192. Keratin, the basic structure element of human hair, is a fibrillar material composed of partially cross-linked polypeptide polymer chains (amnio-acids coupled with peptide links) which are lined up along the fiber axis. When parallel to one another, these chains are cross-linked by SH and H bonds. In the normal unstretched hair, these polypeptide grids are arranged in a regularly folded pattern, and are said to be "buckled" or "kinked." This arrangement is referred to as alpha keratin.4 Stretching such a fiber involves the unbuckling of polypeptide chains and accounts for the fiber's elasticity. When unbuckled or flat, the configuration of these grids is called beta keratin. The strength of hair is related to the strength of its peptide bonds. Bull and Gutman5 state that when a hair is stretched from 3% to 20%, the process resembles a thixotropic gel-sol transformation. (Thixotropic is the property exhibited by certain gels of becoming fluid when shaken and then becoming solid again. A gel is a colloid firm in consistency though containing much liquid, i.e., a "gelatinous form.") cal Fig. 1. Cross-section of a human hair. (From Bouthilet, Karker, and Johnsen2 ) CUTICLE corti Cells Medulla
Object Description
Rating | |
Fixed Title * | NCHH-17: North Carolina Medical Journal [1940-Present] |
Document Title | North Carolina Medical Journal [1940-Present] |
Subject Topical Other | Public Health -- Periodicals.; Physicians -- North Carolina -- Directory.; Societies, Medical -- North Carolina -- Periodicals. |
Description | Includes Transactions of the Society, -1960; 1961- , Transactions issued separately, bound in.; Includes Transactions of the auxiliary to the Medical Society of the State of North Carolina and Proceedings of the North Carolina Public Health Association. Official organ of the Medical Society of the State of North Carolina, 1940-May 1972; of the North Carolina Medical Society, June 1972-. Vols. for 1940-May 1972 published by the Medical Society of the State of North Carolina; June 1972- by the North Carolina Medical Society. |
Contributor | Medical Society of the State of North Carolina. Transactions.; Medical Society of the State of North Carolina.; North Carolina Medical Society.; North Carolina Medical Society. Transactions.; North Carolina Public Health Association. Proceedings. |
Publisher | [Winston-Salem] : North Carolina Medical Society [etc.], 1940- |
Repository | University of North Carolina at Chapel Hill. Health Sciences Library. |
Host | University of North Carolina at Chapel Hill |
Date | 1970 |
Identifier | NCHH-17-031 |
Form General | Periodicals |
Language | English |
Rights | This item is part of the North Carolina History of Health Digital Collection. Some materials in the Collection are protected by U.S. copyright law. This item is presented by the Health Sciences Library of the University of North Carolina at Chapel Hill for research and educational purposes. It may not be republished or distributed without permission of the Health Sciences Library. |
Digital Collection | North Carolina History of Health Digital Collection |
Sponsor | The North Carolina History of Health Digital Collection is an open access publishing initiative of the Health Sciences Library of the University of North Carolina at Chapel Hill. Financial support for the initiative was provided in part by a multi-year NC ECHO (Exploring Cultural Heritage Online) digitization grant, awarded by the State Library of North Carolina, and funded through the Library Services and Technology Act (LSTA). |
Volume Number | 31 |
Health Discipline | Medicine |
Digital Format | JPEG 2000 |
Print / Download PDF Version | http://archives.hsl.unc.edu/nchh/nchh-17/nchh-17-031.pdf |
Document Sort | all; nchh-17 |
Volume Link | http://dc.lib.unc.edu/cdm/search/collection/nchh/field/identi/searchterm/NCHH-17-031 |
Title Link | http://dc.lib.unc.edu/cdm/search/collection/nchh/field/documa/searchterm/NCHH-17 |
Catalog Record link | http://search.lib.unc.edu/search?R=UNCb1306322 |
Revision History | done |
Description
Fixed Title * | Page 172 (image) |
Document Title | North Carolina Medical Journal [1940-Present] |
Subject Topical Other | Public Health -- Periodicals.; Physicians -- North Carolina -- Directory.; Societies, Medical -- North Carolina -- Periodicals. |
Description | Includes Transactions of the Society, -1960; 1961- , Transactions issued separately, bound in.; Includes Transactions of the auxiliary to the Medical Society of the State of North Carolina and Proceedings of the North Carolina Public Health Association. Official organ of the Medical Society of the State of North Carolina, 1940-May 1972; of the North Carolina Medical Society, June 1972-. Vols. for 1940-May 1972 published by the Medical Society of the State of North Carolina; June 1972- by the North Carolina Medical Society. |
Contributor | Medical Society of the State of North Carolina. Transactions.; Medical Society of the State of North Carolina.; North Carolina Medical Society.; North Carolina Medical Society. Transactions.; North Carolina Public Health Association. Proceedings. |
Publisher | [Winston-Salem] : North Carolina Medical Society [etc.], 1940- |
Repository | University of North Carolina at Chapel Hill. Health Sciences Library. |
Host | University of North Carolina at Chapel Hill |
Date | 1970 |
Identifier | NCHH-17-031-0238 |
Form General | Periodicals |
Page Type | all; all images; diagram; article; article title |
Language | English |
Rights | This item is part of the North Carolina History of Health Digital Collection. Some materials in the Collection are protected by U.S. copyright law. This item is presented by the Health Sciences Library of the University of North Carolina at Chapel Hill for research and educational purposes. It may not be republished or distributed without permission of the Health Sciences Library. |
Filename | ncmed311970mediv1_0238.jp2 |
Digital Collection | North Carolina History of Health Digital Collection |
Sponsor | The North Carolina History of Health Digital Collection is an open access publishing initiative of the Health Sciences Library of the University of North Carolina at Chapel Hill. Financial support for the initiative was provided in part by a multi-year NC ECHO (Exploring Cultural Heritage Online) digitization grant, awarded by the State Library of North Carolina, and funded through the Library Services and Technology Act (LSTA). |
Volume Number | 31 |
Issue Number | 5 |
Page Number | 172 |
Health Discipline | Medicine |
Full Text | 172 May, 1970 Tensile Characteristics of Human Hair and Some Effects of Hair Spray DAVID G. WELTON, M.D. and WALTER E. NOREM, PhD. For centuries man has been concerned with the appearance (and disappearance) of the hair on his head. In order to enhance his general appearance and to keep up with the ever-changing styles, man has subjected his hair to brushing, combing, washing, rinsing, drying, curling, teasing, and straightening, and to the application of tints, dyes, oils, powders, sprays, and many other chemical preparations. Some of these treatments may alter physical characteristics of hair—such as its breaking strength, ductility (extensibility), or toughness, and thereby may play a role in certain disorders of the hair and scalp. While there are numerous reports in the engineering and other technical literature about measurements of various physical characteristics of hair and its mechanical behavior under stress, there are few such reports in the medical literature of the last 15 years. An exception is Price and Menafee's recent report that dimethyl sulfoxide in concentrations of about 80% produced a marked increase in the stress relaxation of human hair.1 Presented herein are (1) a brief review of the structure of human hair: (2) a description of the chemical composition and properties of hair sprays; (3) a discussion of the tensile properties of engineering materials; and (4) a report of an experimental procedure in which tensile characteristics of normal hair were studied before and after the application of hair spray. Structure of Hair A human hair may be visualized as a complex fiber composed (Fig. 1.) of a thin, outer layer, its "cuticle" then a cylindrical Read in part befpre the American Dermato logical Association, Dorado Beach, Puerto Rico, April 6, 1968. ♦Dr. Welton is in private practice in Charlotte, and is Clinical Associate, Department of Dermatology, Duke University Medical Center. ♦♦Dr. Norem is Associate Professor of Engineering Materials, Universityof North Carolina at Charlotte. Reprint requests to 1012 South Kings Drive, Charlotte, N. C. 28207 (Dr. Welton). mass of fibrils or "cortical cells" and an inner core or "medulla."2 A diagrammatic representation at various levels of magnification is shown in Figure 2.3 Editorial comment on page 192. Keratin, the basic structure element of human hair, is a fibrillar material composed of partially cross-linked polypeptide polymer chains (amnio-acids coupled with peptide links) which are lined up along the fiber axis. When parallel to one another, these chains are cross-linked by SH and H bonds. In the normal unstretched hair, these polypeptide grids are arranged in a regularly folded pattern, and are said to be "buckled" or "kinked." This arrangement is referred to as alpha keratin.4 Stretching such a fiber involves the unbuckling of polypeptide chains and accounts for the fiber's elasticity. When unbuckled or flat, the configuration of these grids is called beta keratin. The strength of hair is related to the strength of its peptide bonds. Bull and Gutman5 state that when a hair is stretched from 3% to 20%, the process resembles a thixotropic gel-sol transformation. (Thixotropic is the property exhibited by certain gels of becoming fluid when shaken and then becoming solid again. A gel is a colloid firm in consistency though containing much liquid, i.e., a "gelatinous form.") cal Fig. 1. Cross-section of a human hair. (From Bouthilet, Karker, and Johnsen2 ) CUTICLE corti Cells Medulla |
Digital Format | JPEG 2000 |
Print / Download PDF Version | http://archives.hsl.unc.edu/nchh/nchh-17/nchh-17-031.pdf |
Document Sort | all; nchh-17 |
Article Title | Tensile Characteristics Of Human Hair And Some Effects Of Hair Spray |
Article Author | David G. Welton; Walter E. Norem |
Volume Link | http://dc.lib.unc.edu/cdm/search/collection/nchh/field/identi/searchterm/NCHH-17-031 |
Title Link | http://dc.lib.unc.edu/cdm/search/collection/nchh/field/documa/searchterm/NCHH-17 |
Catalog Record link | http://search.lib.unc.edu/search?R=UNCb1306322 |
Revision History | done |
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