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Quantifying the impact of braiding and combing on the integrity of natural African hair
Abstract
Background
Afro hair breakage is most commonly attributed to grooming practices such as braiding, hair extensions and weaves, both for chemically treated hair and natural Afro hair. These grooming practices are also frequently associated with traction alopecia in clinical studies. However, there is little to no quantitative scientific data on the surface and internal hair fibre damage caused by grooming, including combing, on Afro hair.
Methods
Qualitative and quantitative techniques such as scanning electron microscopy, cuticle cohesion and tensile testing were used to determine the effects of frequent braiding on the integrity of female Afro hair in 15 frequent braiders and 15 occasional braiders (control group) in Johannesburg, South Africa. Frequent braiders were women who braided more than 8 times per year, while occasional braiders typically limit braiding to only twice 2 per year. The severity of traction alopecia was quantified in both groups using the standard Marginal Traction Alopecia Scoring system. Surface damage on naturally curly Afro hair, that was combed but not braided, was assessed as another hairstyle option.
Results
All measurements showed a relationship between surface and internal hair fibre damage and braiding frequency. Frequent braiders had thinner hair, with more cuticle damage as shown by SEM and cuticle cohesion assessments. Their hair fibres were also significantly weaker (p<0.05), as shown by the tensile testing. In addition, they also had higher traction alopecia severity scores. In the combing impact assessment, a linear trend was observed between surface hair fibre damage and the number of combing strokes. Cuticle damage from 480 combing strokes was more severe than that from frequent braiding.
Conclusion
Frequent braiding and combing damage natural Afro hair. Quantification of damage caused by different grooming practices, identifies a need to develop products that could help mitigate specific hair damage associated with grooming practices. The degree of damage and subsequent hair loss could also be minimized by education on best braiding practices to protect the hair fibre and avoid hair follicle miniaturization caused by high traction hairstyles.
... For the participants with relaxed hair, there are multiple insults on the hair and scalp from the inherent weakness and dryness of the African curly hair, the increased hair fragility caused by the hair straighteners and texturisers, as well as the physical trauma and traction caused by various indigenous hairstyles such as twists, braids, ponytails, cornrows, plaiting and extensions done by individuals of African descents. [16,31,32] The choice of these hairstyles includes social media trends, fashions, cultural acceptability, Eurocentric standards of beauty and professionalism, neatness, reduced need to comb and ease of management of the hair. [31,33] One month duration between hair wash cycles was the most reported in this study. ...
... [16,31,32] The choice of these hairstyles includes social media trends, fashions, cultural acceptability, Eurocentric standards of beauty and professionalism, neatness, reduced need to comb and ease of management of the hair. [31,33] One month duration between hair wash cycles was the most reported in this study. The study also found that there were more hair problems or complications with longer duration of hair wash cycles, while those with shorter intervals between hair washing had fewer hair problems or complaints [ Figure 1]. ...
Introduction:
The scalp hairs on an average African is dry with low tensile strength and a tendency to break easily. This is mostly due to poor penetration of the natural oils on the scalp and the very curly hair texture. Various techniques developed to manage African hair are associated with certain hair and scalp disorders and are sources of distress.
Objectives:
This was a cross-sectional survey to compare natural African hair and chemically processed (relaxed) hair to determine the effect of hair care and grooming practices on common scalp disorders and the psychological effect in Nigerian women.
Subjects and methods:
Questionnaires were administered to women at the market, churches and outreaches with many women in attendance to document the hair grooming practices, common scalp symptoms and psychological effects experienced. They were also examined for the presence of seborrhoeic dermatitis and traction alopecia.
Results:
The study involved 452 women (62.17%) with relaxed hair and 275 women (37.83%) with natural (untreated) hair. Women with relaxed hair experienced significantly more flaking of the scalp (P = 0.046, x2 = 6.16), hair breakage (P = 0.023, x2 = 11.35) and hair loss (P = 0.020, x2 = 7.87) than those with natural hair. The most common psychological effects of hair scalp disorders in all participants were feeling of uneasiness 142 (19.5%), frustration 49 (6.7%), poor body image 40 (5.5%) and anger 38 (5.2%). Significantly more women with relaxed hair experienced moderate hair loss from traction than women with natural hair (P = 0.014, x2 = 8.52).
Conclusion:
Nigerian women experienced clinical and psychological distress consequent to their hair grooming practices. Individuals with relaxed hair had more physical symptoms, hair loss and psychological disturbances than those with natural hair.
... Additionally, none of these hairstyles utilize chemical straightening, and apart from dreadlocks, are considered "protective hairstyles" because they do not require excessive daily manipulation. They can be used to help transition from chemically treated hair to natural hair, effectively masking any differences in structure or texture along the shaft of the hair [42]. ...
... Additionally, TA prevalence was highest with traction from artificial extensions compared with that from natural long hair (dreadlocks), suggesting that artificial extensions may be more damaging to the hair follicle, perhaps due to their additional weight [44]. Mechanical insult from excessive braiding (>eight times/year) was associated with the highest marginal traction alopecia severity scores in a small cohort study done in Johannesburg, South Africa [42]. ...
Hairstyling trends among Black women fluctuate with social, cultural, and environmental pressures. Dermatologists should be aware of current trends and their associated risks in order to provide the best care to this population. In order to summarize the updated trends and associated health risks for the most common hairstyles worn by Black women, a literature review was performed. PubMed and EMBASE were used to identify articles related to hair styling practices, studies on the effects or risks of various styling practices, and magazine articles citing current styling trends among women of African descent. All hairstyles were found to have associated health risks; however, natural styles had the fewest adverse associations of all styles reviewed. Central Centrifugal Cicatricial Alopecia (CCCA) is the most cited hair disorder in this population, possibly linked to both chemical relaxants and traction styles. Additional studies are needed to further establish causality between these styles and CCCA. Additionally, while acceptance of natural hairstyles is on the rise, there is more work to be done throughout society to help protect and encourage women who choose to wear Afrocentric styles. Dermatologists should be well versed in these hairstyles and ready to lend appropriate advice to patients when it is requested.
... 37 There have been a few studies that have measured "fiber-to-fiber" interactions in "African" and "Caucasian" hair fibers in the context of braided hair styles. 29,46 "Emergence angle from the scalp" is the angle at which "living hair" inside the skin polymerizes and grows out of the follicle away from the scalp. 14, 26 The shape of the follicle dictates the shape of the cross-section of each hair fiber (ellipticity, ). ...
Hair is one of the key characteristics that classify us as mammals. It is a natural polymeric composite that is primarily composed of tight macro-bundles of keratin proteins, which are highly responsive to external stimuli, including pH, temperature, and ionic solvent content. The external responsive behavior displayed by hair is similar to the behavior displayed by hydrogels and other natural fibrous gel systems like collagen and fibrin. Hair and its appearance play a significant role in human society. It is a highly complex biocomposite system, which has been traditionally challenging to characterize and thus develop functional personal care products for consumers. Over the last few decades, a significant societal paradigm shift occurred among those with curly hair. They began to accept the natural morphological shape of their curls and style their hair according to its innate, distinct, and unique material properties. These societal and cultural shifts have given rise the development of new hair classification systems, beyond the traditional and highly limited ethnicity-based distinction between Caucasian, Mongolian, and African. L’Oréal developed a hair typing taxonomy based on quantitative geometric parameters displayed among the four key curl patterns – straight, wavy, curly, and coily (kinky). However, the system fails to capture the complex diversity of curly and kinky/coily hair. Acclaimed celebrity hair stylist, Andre Walker, developed a classification system that is the existing gold standard for classifying curly and kinky/coily hair, however the system relies upon qualitative classification measures, making the system vague and ambiguous to the full diversity of phenotypic differences. The goal of this research is to use quantitative methods to identify new geometric parameters, which will be more representative of curly and kinky/coily hair curl patterns. These new parameters will therefore provide more information on the kinds of personal care product ingredients that will resonate best with these curl patterns, and thus maximize desired appearance and overall hair health. The goal is also to correlate these new parameters with its mechanical properties. This was accomplished by identifying new geometric and mechanical parameters from several types of human hair samples. Geometric properties were measured using scanning electron microscopy (SEM), photogrammetry, and optical microscopy. Mechanical properties were measured under tensile extension using a texture analyzer (TA) and a dynamic mechanical analyzer (DMA), which bears similarity to the common act of brushing or combing. Both instruments measure force as a function of applied displacement, thus allowing the relationship between stress and applied stretch ratio to be measured as a hair strand uncurls and stretches to the point of fracture. From the resulting data, correlations were made between fiber geometry and mechanical performance. This data will be used to draw more conclusions on the contribution that fiber morphology has on hair fiber mechanics and will promote cultural inclusion among researchers and consumers possessing curly and kinky/coily hair.
... 29 People with African hair types are prone to hair loss secondary to certain cultural styling practices, such as tight braiding that can cause traction alopecia and scarring. 30,31 Harsh chemicals that are used to relax and straighten hair also contribute to hair loss, particularly among African American women. 24 This population is also at increased risk of centrifugal cicatricial alopecia (CCCA), marked by in ammation and progressive destruction of follicles through scarring. ...
Objective:
The goal of this study was to assess the perceived efficacy of a standardized nutraceutical to improve hair growth and quality in men and women of various ethnicities with self-perceived hair thinning.
Methods:
This prospective, single-blind study enrolled healthy men aged 20 to 55 years (n=47) and premenopausal women aged 20 to 45 years (n=51) with self-perceived, mild-to-moderate hair thinning and included African American, Asian, Hispanic Caucasian and Non-Hispanic Caucasian participants. The nutraceutical supplement (Nutrafol® Men or Women Capsules, Nutraceutical Wellness Inc., New York, New York) was taken daily for six months. Subjects were evaluated in the clinic at baseline and Weeks 12 and 24 with two self-assessments at Weeks 4 and 8. Study endpoints were standardized digital imaging and investigator rated assessments. Self-assessment questionnaires rated hair growth, hair satisfaction, and lifestyle factors.
Results:
Investigator ratings for baseline hair growth, coverage, density, and volume were significant at Weeks 12 and 24 for all subjects (for each, p<0.001). These significant improvements were seen in 83.7 percent of men and 79.5 percent of women at Week 24. Results were similar across ethnic subgroups with significant benefit at Weeks 12 and 24 (for each, p<0.05). All subjects reported significant improvements in baseline hair appearance/quality, volume/fullness, scalp coverage, thickness, and shedding at Weeks 4, 8, 12 and 24 (for each, p<0.01).
Conclusion:
A standardized nutraceutical supplement improved visible hair growth with less notable shedding based on subjects' and investigators' overall perception of treatment benefit for men and women of various ethnic backgrounds.
ConspectusHair is a natural polymeric composite primarily composed of tight macrobundles of keratin proteins, which are highly responsive to external stimuli, similarly to the hydrogels and other natural fibrous gel systems like collagen and fibrin.Hair and its appearance play a significant role in human society. As a highly complex biocomposite system, it has been traditionally challenging to characterize and thus develop personal care products. Over the last few decades, a significant societal paradigm shift occurred among those with curly hair, accepting the natural morphological shape of their curls and styling their hair according to its innate, distinct, and unique material properties, which has given rise to the development of new hair classification systems, beyond the traditional and highly limited race-based distinction (Caucasian, Mongolian, and African). L'Oréal developed a hair typing taxonomy based on quantitative geometric parameters among the four key patterns─straight, wavy, curly, and kinky, but it fails to capture the complex diversity of curly and kinky hair. Acclaimed celebrity hair stylist Andre Walker developed a classification system that is the existing gold standard for classifying curly and kinky hair, but it relies upon qualitative classification measures, making the system vague and ambiguous of phenotypic differences. The goal of this research is to use quantitative methods to identify new geometric parameters more representative of curly and kinky hair curl patterns, therefore providing more information on the kinds of personal care products that will resonate best with them and thus maximize desired appearance and health, and to correlate these new parameters with its mechanical properties. This was accomplished by identifying new geometric and mechanical parameters from several types of human hair samples.Geometric properties were measured using scanning electron microscopy (SEM), photogrammetry, and optical microscopy. Mechanical properties were measured under tensile extension using a texture analyzer (TA) and a dynamic mechanical analyzer (DMA), which bears similarity to the common act of brushing or combing. Both instruments measure force as a function of applied displacement, thus allowing the relationship between stress and applied stretch ratio to be measured as a hair strand uncurls and stretches to the point of fracture. From the resulting data, correlations were made between fiber geometry and mechanical performance. This data will be used to draw more conclusions on the contribution that fiber morphology has on hair fiber mechanics and will promote cultural inclusion among researchers and consumers possessing curly and kinky hair.
Chemotherapy‐induced alopecia (CIA) can be a devastating side effect of breast cancer treatment for all racial groups, but may carry unique historical, social, political, and cultural significance for Black patients. Oncologists should gain a deeper understanding of the impact of CIA among their Black patients.
Hair is one of the key characteristics that classify us as mammals. It is a natural polymeric composite that is primarily composed of tight macro-bundles of keratin proteins, which are highly responsive to external stimuli, including pH, temperature, and ionic solvent content. The external responsive behavior displayed by hair is similar to the behavior displayed by hydrogels and other natural fibrous gel systems like collagen and fibrin. Hair and its appearance play a significant role in human society. It is a highly complex biocomposite system, which has been traditionally challenging to characterize and thus develop functional personal care products for consumers. Over the last few decades, a significant societal paradigm shift occurred among those with curly hair. They began to accept the natural morphological shape of their curls and style their hair according to its innate, distinct, and unique material properties. These societal and cultural shifts have given rise the development of new hair classification systems, beyond the traditional and highly limited ethnicity-based distinction between Caucasian, Mongolian, and African. L’Oréal developed a hair typing taxonomy based on quantitative geometric parameters displayed among the four key curl patterns – straight, wavy, curly, and coily (kinky). However, the system fails to capture the complex diversity of curly and kinky/coily hair. Acclaimed celebrity hair stylist, Andre Walker, developed a classification system that is the existing gold standard for classifying curly and kinky/coily hair, however the system relies upon qualitative classification measures, making the system vague and ambiguous to the full diversity of phenotypic differences. The goal of this research is to use quantitative methods to identify new geometric parameters, which will be more representative of curly and kinky/coily hair curl patterns. These new parameters will therefore provide more information on the kinds of personal care product ingredients that will resonate best with these curl patterns, and thus maximize desired appearance and overall hair health. The goal is also to correlate these new parameters with its mechanical properties. This was accomplished by identifying new geometric and mechanical parameters from several types of human hair samples. Geometric properties were measured using scanning electron microscopy (SEM), photogrammetry, and optical microscopy. Mechanical properties were measured under tensile extension using a texture analyzer (TA) and a dynamic mechanical analyzer (DMA), which bears similarity to the common act of brushing or combing. Both instruments measure force as a function of applied displacement, thus allowing the relationship between stress and applied stretch ratio to be measured as a hair strand uncurls and stretches to the point of fracture. From the resulting data, correlations were made between fiber geometry and mechanical performance. This data will be used to draw more conclusions on the contribution that fiber morphology has on hair fiber mechanics and will promote cultural inclusion among researchers and consumers possessing curly and kinky/coily hair.
An attempt to understand and explain a peculiarity that was observed for curly fibres during experimentation revealed disparate literature reporting on several key issues. The phenotypical nature of curly fibres is only accurately understood within the larger scope of hair fibres, which are highly complex biological structures. A brief literature search produced thousands of research items. Besides the large amount of information on the topic, there was also great variability in research focus. From our review, it appeared that the complexity of hair biology, combined with the variety of research subtopics, often results in uncertainty when relating different aspects of investigation. During the literature investigation, we systematically categorized elements of curly hair research into three basic topics: essentially asking why fibres curl, what the curly fibre looks like and how the curly fibre behaves. These categories were subsequently formalized into a curvature fibre model that is composed of successive but distinctive tiers comprising the elements in curly hair research. The purpose of this paper is twofold: namely to present (i) a literature review that explores the different aspects of curly human scalp hair and (ii) the curvature fibre model as a systemized approach to investigating curly hair.
Purpose:
To provide data for forensic use and provoke ideas to preserve shaft integrity, we studied microstructural alterations of female scalp hair subjected to Ghanaian cultural styling methods. Hence, topographical features of female hairs styled by braiding/weaving, and chemical relaxation sampled from five different scalp regions were assessed and compared with natural (Afro) hair.
Subjects and methods:
Ninety-six indigenous Ghanaian females volunteered 480 hairs, which were analyzed by light microscopy. Hairs were plucked using a pair of cosmetologist's tweezers from frontal, left temporal, right temporal, vertex, and occipital regions of the scalp. Hairs were categorized by their grooming styles as Afro (natural-unstyled), natural-styled (weaved/braided), and chemically relaxed. These were studied according to shaft/medulla dimensions and conventional cuticular scale features, and comparisons were made between styling procedures and scalp regions.
Results:
Chemically styled hair had the widest shaft diameter, but the lowest incidence of continuous medullation. Medullary diameter and index increased from chemically relaxed, natural-styled, to Afro hair. A positive but modest correlation between shaft and medullary diameters existed for Afro (r = 0.320, p = 0.011) and natural-styled hairs (r = 0.235, p = 0.022) but not chemically relaxed hair (r = 0.122, p = 0.2). Scale margins were predominantly smooth in Afro hair, crenate in natural-styled hair, and rippled in chemically relaxed hair. With respect to scalp regions, hair shaft diameter was widest in vertex hair and smallest in right temporal hair in all styling methods.
Conclusion:
Medulla was thickest in Afro hair, which also exhibited a correlation with shaft diameter in conformity with the published data. Chemically relaxed hairs did not exhibit these characteristics, which affirm altered morphology. Research on how chemicals affect these changes should help find antidote. The dimensional variations of hairs from different scalp regions are instructive for both cosmetic and forensic examination of hairs.
Significance
Air pollution via phototoxic polycyclic aromatic hydrocarbons (PAHs) is a major risk factor for human health. While in vitro observations and in vivo correlations suggest a detrimental effect of PAHs at physiological concentrations, in vivo observations of the structural impact of PAHs are scarce. Here, we use transmission electron microscopy on human hair fibers containing known concentrations of 25 biomarkers of PAH exposure. We show an increased structural degradation of the hair fiber over time, when increased PAH concentrations are present. Moreover, we show that exposure to UV radiation explains part of the increased damage in more contaminated fibers. Our results point toward possible detrimental effects in other human tissues at physiological concentrations of PAHs.
Background
Central centrifugal cicatricial alopecia (CCCA) is the most common form of scarring alopecia among women of African ancestry. The disease is occasionally observed to affect women in families in a manner that suggests an autosomal dominant trait and usually manifests clinically after intense hair grooming. We sought to determine whether there exists a genetic basis of CCCA and, if so, what it is.
Methods
We used exome sequencing in a group of women with alopecia (discovery set), compared the results with those in a public repository, and applied other filtering criteria to identify candidate genes. We then performed direct sequencing to identify disease-associated DNA variations and RNA sequencing, protein modeling, immunofluorescence staining, immunoblotting, and an enzymatic assay to evaluate the consequences of potential etiologic mutations. We used a replication set that consisted of women with CCCA to confirm the data obtained with the discovery set.
Results
In the discovery set, which included 16 patients, we identified one splice site and three heterozygous missense mutations in PADI3 in 5 patients (31%). (The approximate prevalence of the disease is up to 5.6%.) PADI3 encodes peptidyl arginine deiminase, type III (PADI3), an enzyme that post-translationally modifies other proteins that are essential to hair-shaft formation. All three CCCA-associated missense mutations in PADI3 affect highly conserved residues and are predicted to be pathogenic; protein modeling suggests that they result in protein misfolding. These mutations were found to result in reduced PADI3 expression, abnormal intracellular localization of the protein, and decreased enzymatic activity — findings that support their pathogenicity. Immunofluorescence staining showed decreased expression of PADI3 in biopsy samples of scalp skin obtained from patients with CCCA. We then directly sequenced PADI3 in an additional 42 patients (replication set) and observed genetic variants in 9 of them. A post hoc analysis of the combined data sets showed that the prevalence of PADI3 mutation was higher among patients with CCCA than in a control cohort of women of African ancestry (P=0.002 by the chi-square test; P=0.006 by Fisher’s exact test; and after adjustment for relatedness of persons, P=0.03 and P=0.04, respectively).
Conclusions
Mutations in PADI3, which encodes a protein that is essential to proper hair-shaft formation, were associated with CCCA. (Funded by the Ram Family Foundation and others.)
Female alopecia patients in China often present with a frontal pattern hair loss. This feature is seen less frequently in western women. Women in China frequently style their hair in a ponytail. Thus, we hypothesized that the high prevalence of frontal pattern hair loss in Chinese women is due to traction alopecia. To better understand this, we studied forty‐three women presenting frontal alopecia at a hospital hair clinic. Among the women presenting frontal alopecia, 79% reported styling their hair in a ponytail four or more days per week for an average period of 10 years. To our knowledge, this is the first study to elucidate the cause of frequent frontal alopecia in Chinese women. While cultural style changes are difficult to change, we believe that awareness of the medical implications of frequent ponytail styling will reduce the rate of frontal alopecia among Chinese women.
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Ingrid Herskovitz, Mariya Miteva Department of Dermatology and Cutaneous Surgery, University of Miami L Miller School of Medicine, Miami, FL, USA Abstract: Central centrifugal cicatricial alopecia (CCCA) is the most common scarring alopecia among African American women. Data about epidemiology, etiology, genetic inheritance, and management are scarce and come from individual reports or small series. CCCA has been associated with hot combing and traumatic hair styling for years; however, studies fail to confirm it as the sole etiologic factor. It has been shown in a small series that CCCA can be inherited in an autosomal dominant fashion, with a partial penetrance and a strong modifying effect of hairstyling and sex. CCCA presents clinically as a central area of progressive irreversible hair loss that expands to the periphery. A patchy form has also been described. Dermoscopy is helpful to identify the optimal site for the biopsy, which establishes the diagnosis. Well-designed randomized controlled trials are needed to discover the optimal management. At this point, patients are advised to avoid traction and chemical treatments; topical and intralesional steroids, calcineurin inhibitors, and minoxidil can be helpful in halting the progression. Keywords: hair loss, alopecia, dermatoscopy, dermoscopy, trichoscopy, black scalp, African American, scarring alopecia
Afro-ethnic hair is different from Caucasian and Asian hair and has unique features. Ethnic hair is more prone to certain conditions or diseases. Such diseases are not only related to the fragile inner structure of the hair, but also to the cultural habits of hairstyles that often exert traction forces upon the pilosebaceous follicle. Women with African hair subject their hair to chemical treatments such as hair straightening and relaxing, and thus modify the structure of their hair shaft, making it more susceptible to damage. For this reason, hair complaints are common among black women and represent a diagnostic challenge to the dermatologist, requiring a thorough clinical examination of the hair and scalp, and a detailed medical history of the patient. The purpose of this review is to warn of the potential side effects and sequelae related to hairstyles and hair treatments used by black women, and to highlight the major diseases that affect this ethnicity.
Background:
In 2005, the L'Oréal Institute for hair and skin research carried out a multiethnic study to investigate hair breakage in women residing in the U.S.A. In this study it was reported that a large percentage (96%) of the African-American respondents experience breakage. A combination of structural differences and grooming-induced stresses seem to contribute to the higher breakage incidence in the African-American group as the chemical composition of African-American hair is not significantly different from other ethnic groups. Some authors have proposed that the repeated elongation, torsion and flexion actions may affect the components of the hair fibre. However, considering the different properties of cuticle and cortex, one would expect a different wearing mechanism of each, leading to the ultimate failure of hair. Knowing in detail how each part of the structure fails can potentially lead to better ways to protect the hair from physical insults.
Objective:
To investigate crack propagation and fracture mechanisms in African-American hair.
Methods:
Virgin hair of excellent quality was collected, with informed consent, from a female African-American volunteer. A series of controlled mechanical stresses was applied to 10-mm hair sections using a high-resolution mechanical stage (20 mN) up to the fracture of the fibre. The surface was monitored using scanning electron microscopy imaging during the stress application. X-ray tomographic microscopy images were acquired and quantified to detect changes in energy absorption as a function of applied stress that could be linked to increase in crack density.
Results:
Analysis of the mechanical response of hair combined with the two imaging techniques led us to propose the following mechanism of hair breakage: cuticle sliding; failure of the cuticle-cortex interface; nucleation of intercellular cracks and growth of cracks at the cuticle-cortex junction; and propagation of intercellular cracks towards the surface of the hair and final breakage when these cracks merge at the cuticular junction.
Conclusions:
The combination of scanning electron microscopy and X-ray tomography provided new information about the fracture of hair. Mechanical damage from grooming and some environmental factors accumulate in hair creating internal cracks that eventually result in breakage at unpredictable sites and therefore a continuous care regimen for the hair throughout the life cycle of the fibres is recommended.
Human hair has been commonly classified according to three conventional ethnic human subgroups, that is, African, Asian, and European. Such broad classification hardly accounts for the high complexity of human biological diversity, resulting from both multiple and past or recent mixed origins. The research reported here is intended to develop a more factual and scientific approach based on physical features of human hair. The aim of the study is dual: (1) to define hair types according to specific shape criteria through objective and simple measurements taken on hairs from 1442 subjects from 18 different countries and (2) to define such hair types without referring to human ethnicity. The driving principle is simple: Because hair can be found in many different human subgroups, defining a straight or a curly hair should provide a more objective approach than a debatable ethnicity-based classification. The proposed method is simple to use and requires the measurement of only three easily accessible descriptors of hair shape: curve diameter (CD), curl index (i), and number of waves (w). This method leads to a worldwide coherent classification of hair in eight well-defined categories. The new hair categories, as described, should be more appropriate and more reliable than conventional standards in cosmetic and forensic sciences. Furthermore, the classification can be useful for testing whether hair shape diversity follows the continuous geographic and historical pattern suggested for human genetic variation or presents major discontinuities between some large human subdivisions, as claimed by earlier classical anthropology.
Hairs collected from 257 Mexican women, residing in Mexico City, were characterized by instrumental measurements for comparison to more‐commonly reported Caucasian, Asian and African hairs. Subjects were subdivided into 5 age groups and their hairs were characterized by fiber dimension, shape and tensile strength. Results show that Mexican hair appears to be intermediate of Asian and Caucasian hair in diameter and cross‐sectional ellipticity. Such findings seem in line with the early and late ethnic origins of Mexican people. Results also illustrate and confirm the large intra and inter‐individual variability within any single hair property. Unexpectedly high levels of hair tensile damage were sometimes encountered.
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A 32‐year‐old previous healthy woman was observed with a 3‐year history of hair loss. On physical examination, she had decreased hair density and smooth padded alopecic patches on the occipital and parietal scalp. The fronto/temporal hair rim was preserved. A positive Jacquet's sign was present with easy formation of several folds in the occipito/parietal scalp; the pull test was negative.
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Hairstyles vary significantly across ethnic populations and are often thought of as an expression of personal style and a celebration of cultural heritage. This chapter provides an overview of the wide variety of hairstyles and hair prostheses most commonly used in the black community as well as the potential harmful effects associated with them. It also includes a brief discussion of camouflage techniques for patients with hair loss.
This chapter describes tensile, bending and torsional testing including different parameters of each of these deformations and how these are affected by different types of hair including different types of hair damage. Expanded data sets are included for elastic moduli and other parameters of these deformations. A new section describing the historical development for assessing and measuring hair fiber curvature along with a new method for curvature has been developed and applied to more than 2,400 persons from more than 20 different countries. This method and data are featured in this section. Methods to determine the different dimensions of hair fibers including axial (length and curvature) and transverse dimensions (diameter, cross-sectional area and ellipticity) are described with much expanded data sets. Information on hair fiber friction (both high load and low load friction) and how friction varies with fiber diameter, comb composition and hair damage are included. Mechanical fatiguing, extension cycling and their effects on hair damage including scale lifting are described in the final section on the physical properties of hair fibers.
Background:
There is a lack of published data pertaining to the hair grooming practices of women of African descent in Europe. However, these data are important in facilitating culturally appropriate discussions on hair loss prevention.
Objective:
We sought to describe the hair grooming practices of adult women of African descent in London, UK.
Method:
Analysis of pooled data collected from a questionnaire-based study exploring correlates of hair loss in women of African descent in London.
Results:
A maximum of 242 subjects were included in the final data analysis. Subjects had a mean age of 41.1 years (CI: 39.3-42.9) and exhibited a diverse range of scalp hair phenotypes, although the majority (76.3%) had type 6, 7 or 8 hair. A percentage of 64.9 had more than five different hairstyles since childhood, with natural hairstyles being the most frequent current hairstyle (52.6%). The mean frequency of hair washing was 17.9 days (CI: 15.8-20.0), increasing to 32.8 days (28.6-37.0) when hair was braided or in a weave. The mean frequency of hair braiding/weaving was 63 days (CI: 56.3-69.7), whereas that for application of chemical relaxers was 88.6 days (CI: 75.6-101.6). While 59.2% of subjects avoided concurrent use of hair colours and chemical relaxers, only 46.3% avoided braiding chemically relaxed hair.
Conclusions:
The hair-care practices of women of African descent should be borne in mind when treating hair and scalp disorders in this group. Although the current trend is towards natural hairstyles, some adverse hair-care practices still persist which should be addressed through culturally appropriate public health messages on hair loss prevention.
Previous findings, based upon a worldwide study, classified the shapes of human hair into 8 major types, from straight to highly curly. This clearly extended the usual classification of hair into African, Asian or Caucasian types. However, determinations of hair growth parameters and hair density were excluded from such studies. To measure and compare the hair growth profiles of young adults without alopecia living in the five continents. 2249 young adults (18-35y, females and males) without alopecia, originating from 24 various human ethnic groups were included in the study. Total hair density, telogen percentage and growth rate on three different scalp areas were measured, using non-invasive validated techniques. Natural hair colour level, curliness and hair diameter were additionally recorded, when practically possible. Diversity in hair growth parameters among the entire cohort was a key finding, the differences appearing linked to scalp area, gender and geographic origin. Statistical approaches depicted African hair as having lower density and a slower growth rate. Asian hair showed a thicker diameter, with faster growth. Caucasian hair showed a high total hair density. On the one hand, this inter-continental study of hair growth parameters initiates a valuable base-line data of hair in young adults without alopecia. On the other hand, it aims at completing and extending the knowledge of this unique human appendage, of some mosaic features, when observed across the planet.
Human hair consists of proteins, lipids, water, trace elements and pigments. The composition of the first four of these components is the focus of this Chapter. About two decades ago the emphasis on the proteins of hair was on its amino acid constituents which provided important information on the relative amounts of different functional groups in different types of hair and in different regions of the fiber. However, as a result of advances in the characterization and classification of the different proteins and genes of keratins and keratin associated proteins the focus today is on the proteins themselves. Several important new contributions to the composition of the surface layers of hair and the proteins of the cell membrane complex have been and are continuing and therefore are summarized in this Chapter. The current state of changes in the amino acids, proteins and lipids of hair by morphological region (including KAP and keratin proteins and where they reside), chemical and sunlight damage, diet, puberty and menopause, and other factors have been and are being made and are summarized here. An expanded section on metals in hair, where in the fiber these metals reside and the functional groups that they bind to and their effects on hair chemistry, toxicity and disorders are included.
Hair cosmetics are an important tool that helps to increase patient's adhesion to alopecia and scalp treatments. This article reviews the formulations and the mode of action of hair cosmetics: Shampoos, conditioners, hair straightening products, hair dyes and henna; regarding their prescription and safetiness. The dermatologist's knowledge of hair care products, their use, and their possible side effects can extend to an understanding of cosmetic resources and help dermatologists to better treat hair and scalp conditions according to the diversity of hair types and ethnicity.
IntroductionA consumer internet survey conducted by our Institute in2005, of over 1200 women that self-identified as AfricanAmerican, Caucasian, Chinese, or Mexican, determinedthat African-American women experience hair breakageat a statistically higher rate as compared with their Chi-nese, Mexican, and Caucasian counterparts. In fact, 96%said they experienced hair breakage while 23% agreed itwas their biggest hair problem. To better understand thisreported phenomenon of increased fragility, one mustconsider that mechanical fragility of hair may be relatedto innate differences in the structure, the result of variousdiseases, or related to grooming habits and practices. Inthis paper, we review some of the previously reportedstructural differences observed in curly hair, laboratorymeasurements used to evaluate fragility, and the potentialimpact of grooming practices.Historically, human hair was classified along raciallines of Caucasian, Mongolian (Asian), and Negroid(African or of African descent). Early studies investigatedhair diameter, geometric shape, strength, and chemicalreactivity.
Traction alopecia (TA) affects up to 32% of women and 22% of high school girls with Afro-textured hair but can start in the preschool years. Traction induces inflammation and follicle damage. The risk of TA increases with symptomatic traction and combined hairstyles. To influence the practice of hairdressers and at risk individuals and help narrow the knowledge, attitudes, and practices (KAP) gap, scientific data should be translated into simple messages like "tolerate pain from a hairstyle and risk hair loss" and "no braids or weaves on relaxed hair". With appropriate education and public awareness, TA could potentially be eradicated.
Our species, Homo sapiens, evolved in Africa, and humanity's highest levels of genetic diversity are maintained there today. Underlying genetic diversity combined with the great range of solar regimes and climatic conditions found in Africa has contributed to a wide range of human integumentary phenotypes within the continent. Millions of Africans have moved, voluntarily and involuntarily, to other continents in the past 2000 years, and the range of integumentary phenotypes among admixed African diaspora populations is enormous. In this contribution, we do not catalog this variation, but provide basic evolutionary background as to how it developed in the first place.
Synopsis The fracture behavior of Negroid hair was studied to clarify the causes of fiber breakage at low levels of extension. Visual observation and ellipticity measurements reveal frequent twists, with random reversals in direction and pronounced flattening which can lead to stress concentrations during tensile deformation. Simultaneous measurements of the effect of tensile load on extension and on axial angle of untwisting of specimens with a single twist indicate that failure at low extensions is due to the initiation of cracks at numerous flaws near the twists, which relieves torsional stresses in these regions. Extension at failure is higher in wet fibers, probably because plasticization relaxes these stresses. Scanning electron microscopy of fracture ends reveals a predominance of step fractures, indicating a large number of flaws, and a large proportion of fibrillated ends, reflecting poor cohesion between cortical cells. Fatiguing via a method devised to simulate the impact loading occurring during hair grooming appears to accentuate existing fiber damage and/or to reduce intercellular cohesion in the cortex, since fibrillated fracture ends predominate among fibers that fracture during fatiguing. The large number of premature failures in surviving fibers suggests that new damage may be initiated at the highest fatiguing loads and may also occur during combing and picking.
Synopsis Oxidation of hair fibers with diperisophthalic acid can produce extensive damage throughout several cuticle layers that is readily observed microscopically. At the same time, no detectable changes in the tensile properties (wet or dry) are detectable. These results are consistent with the hypothesis that the tensile properties of human hair are due primarily to the cortex, with little or no cuticle involvement. human hair. There is a long-standing hypothesis, that the cortex is primarily responsible for the tensile properties of human hair (1), although there is one publication with limited data suggesting the possibility of some cuticle involvement in the tensile properties of hair (2) and some evidence that wool fibers containing a medulla are weaker than non- medullated fibers (3). If the cortex is primarily responsible for the tensile properties of hair fibers, or even if there be only minor cuticle and/or medullary involvement in the tensile properties of hair, then the tensile properties are primarily an index of cortical damage. Therefore, if the tensile properties do not show change, without any further experimental evidence, such data does not stand as an indication of no hair damage. The lack of cuticle involvement in the tensile properties of hair or even minimal in- volvement might seem surprising, because, for a 70-micron hair fiber with a 4-micron- thick band of cuticular material (2), the cuticle represents approximately 22% of the total fiber cross-sectional area. Thus, it would be somewhat surprising if the cuticle were not involved at all in the tensile properties of human hair. With respect to medullary involvement in the tensile properties of hair, such involve- ment has only been demonstrated for selected wool fibers where the medulla represented more than 70 percent of the cross section (3), and such heavy medullation is not common in human hair. A few years ago, we examined an oxidative treatment for hair based on diperisophthalic acid. We found that under certain conditions this reagent could produce extensive
Background Traction alopecia (TA) is common in African females. Although hairstyles are thought to be causal, the contribution of individual hairstyling variables to TA severity has not been quantified. The aim of the current study was to develop a severity scoring system (M-TAS score) for marginal TA, the commonest form of this disorder, and to test its reliability.
Method The margins of the scalp were divided into anterior and posterior with an imaginary line joining the tips of both ears. The anterior and posterior hairlines were further divided into three using the temporalis muscles and mastoid processes at the hairline as landmarks, respectively. Each examiner assessed each of the six areas. If any were found to have TA, the severity was scored using an examiner assessed system (tested once) or a picture matched score (tested twice). Ten and eight female patients with TA of varying severity were assessed by 11 and 9 examiners (dermatologists, dermatology trainees, and nurses), respectively.
Results The intraclass correlation coefficient (ICC) for interobserver agreement was larger with photograph-matched scores than with examiner estimated scores reaching substantial (0.61–0.80) and excellent (0.81–100) agreement for both anterior and posterior scores irrespective of level of skill of examiner. The ICC for intraobserver agreement with the photograph matched scores was 0.99.
Limitations The diagnosis of normal margin was excellent for the anterior yet poor for the posterior margin with photograph scores. The M-TAS score is not for diagnosis but to assess severity.
Conclusion The photograph-based M-TAS score requires validation with larger samples but could be a useful research tool for elucidating disease prevalence and determinants of TA as well for monitoring response to treatment.
The Coulter principle can be used for analysis of subvisible particles in protein formulations. The approach has several advantages including: an orthogonal operating principle, high sensitivity, ability to detect very small particles, excellent reproducibility, and high-resolution size information. This minireview discusses some of the important considerations that must be taken into account when utilizing the Coulter principle for subvisible particle analysis in protein formulations.
Hair cuticle is the first protection shield of hair against external aggressions such as daily combing or brushing that induce friction, mechanical stress leading to ageing process. The identification of alterations of the hair surface induced by shaking process of various hair fibres, such as virgin and chemically treated Chinese and Caucasian hair, sheds some light on some specific features, e.g. Chinese cuticle is torn out in smaller particles than Caucasian, which seems to be related to geometrical rather than ethnic reasons. The present work also shows that two geometrical parameters of human hair, the inter-scale distance and the scale angle are directly linked to fibre dimensions, regardless of ethnic origin. Representative of hair with an average larger cross-sectional area, Chinese hair shows a slightly smaller inter-scale distance as well as a higher scale angle. On the other hand, Chinese hair cuticle seems to be more sensitive to chemical treatment than Caucasian hair, at least for straightening treatment taken here as an example. Such an approach can be of interest in designing cosmetic products more suited to specific needs of human hair. © 2010 Society of Cosmetic Scientists and the Société Française de Cosmétologie.
J. Cosmet. Sci.,60, 599–616 (November/December 2009)
The objective of this work is to describe an alternative approach for assessing hair breakage. The methodology involves the repeated application of force, together with an evaluation of the number of cycles required before breakage—an approach often termed fatigue testing. The technique provides novel results, which appear to indicate more sizable differences between samples than arise from conventional constant-rate extension experiments. For example, results illustrate a substantially higher tendency for breakage in Afro hair as compared to Caucasian hair—a conclusion that appears in line with consumer experiences. Also, findings suggest a substantially larger contribution from the relative humidity of the environment to the propensity for breakage under these conditions. The fatigue approach also lends itself to a novel means of data analysis in which breakage is treated as a statistical variable rather than as a mechanical parameter. By performing Weibull analysis of the data, a characteristic lifetime and a shape parameter are obtained to characterize the data, while survival probability plots can be generated to predict the propensity for breakage under a specific set of conditions.
J. Cosmet. Sci., 60, 97–109 (March/April 2009)
J. Cosmet. Sci., 60, 97–109 (March/April 2009)
The properties of curly hair from different countries were assessed using geometrical measurements from a laser scanning micrometer and a new hair shape classification method. In addition, tensile tests, 2-D gel electrophoresis, and differential scanning calorimetry (DSC) were performed. Results concluded that hair characteristics are influenced by the degree of curl. For example, curlier hair tended to be more fragile. Interestingly, the degree of curl in hair also was dependent upon the country of origin. DSC and 2-D gel electrophoresis showed that the thermal behavior and the protein markers in hair differed as a function of hair origin. The variability seen in hair characteristics may potentially influence how the hair responds to treatment and these differences could be caused by regional and cultural diversities in the population from where the hair originated.
The cause of central centrifugal cicatricial alopecia (CCCA) in African American women remains to be elucidated.
This study was designed to determine the hair-grooming practices in African American women with and without CCCA and to evaluate possible etiologic factors.
Utilizing a novel survey instrument, the Hair Grooming Assessment Survey, we performed a retrospective comparative survey of the hair-grooming practices of two populations of African American women seen and evaluated at the Department of Dermatology, Henry Ford Hospital in Detroit, MI, between 2000 and 2007. The case group were women with clinical and histologic diagnosis of CCCA, and the control group were those without a history of alopecia.
All 101 surveys that were returned were analyzed (51 from the case group and 50 from the control group). A strong association was found between the use of both sewn-in hair weaving and cornrow or braided hairstyles with artificial hair extensions and CCCA (P < .04, P < .03, respectively). Similarly, women with CCCA were more likely to report a history of "damage", typically defined as uncomfortable pulling and tenderness, from both sewn-in and glued-in weaves, and from cornrow or braided hairstyles with artificial hair extensions (P < .001, P < .02, and P < .03, respectively). In contrast to previous anecdotal beliefs, no correlation was found between the use of either hot combing or hair relaxers and the development of CCCA.
Results are limited by patient recall of past hair grooming practices. Also, as hair grooming practices may vary by geographic region, these results may not be generalized to all women of African descent.
There is a clear difference in both quantitative and qualitative hair grooming practices among African American women with CCCA.
Our recent population studies reported a prevalence of traction alopecia (TA) of 17.1% in African schoolgirls (6-21 years) and of 31.7% in women (18-86 years). More schoolgirls had chemically treated hair than women and disease presence was associated with hairstyles. The aim of this study was to investigate determinants of TA presence and severity in girls and women using data from both studies.
Clinical assessment and a Marginal TA Severity score were used for diagnosis and disease severity, respectively. The data used included 574 schoolgirls and 604 women. The first analysis was multiple logistic regression for disease presence. Exploratory associations for disease severity were assessed using the Spearman rank correlation test. Adults were defined as age 18 years or older, irrespective of study.
The odds ratio for TA was higher in adults than in children (<18 years) (1.87 [P < .001, 95% confidence interval 1.28-2.72]) and was higher with braiding-related than chemical-related symptoms. The highest risk of TA, compared with natural hair, occurred when traction was added to relaxed hair (odds ratio 3.47 [P < .001, 95% confidence interval 1.94-6.20]). Only 18.9% of patients with TA had never had symptoms related to hairdressing. TA severity was associated with age group, current hairstyle, and hairdressing symptoms. Participants with severe disease were too few to estimate determinants.
There is a need for the validation of the Marginal TA Severity score with larger numbers and for future studies to include more participants with severe disease.
Our findings suggest that avoiding both hairdressing symptoms and the addition of traction, especially to chemically processed hair, may reduce the risk of developing TA.
Hair growth parameters have been studied mostly in caucasian hair, whereas few data on African hair have been reported in the literature.
To evaluate hair growth characteristics of African volunteers born in Africa.
Thirty-eight young adults (19 women, 19 men, mean +/- SD age 27 +/- 10 years), native of central and western Africa, took part in the study. Phototrichograms were performed in order to record three parameters of hair growth: hair density, telogen percentage and rate of growth. For each volunteer, three regions of the scalp, namely vertex, temporal and occipital areas, were assessed.
Hair density varied from 90 to 290 hairs cm(-2), with higher counts on the vertex. No significant difference between men and women was recorded. Telogen percentage showed wide variations, from 2 to 46%, with higher levels on the temporal area and in men. The rate of growth fluctuated from 150 to 363 microm day(-1) with no difference related either to gender or to scalp region. These data were compared with those previously obtained in caucasian volunteers of comparable age, and showed significant differences between the two ethnic groups in all three parameters studied. Hair density in African volunteers was lower than that in caucasians (mean +/- SD 190 +/- 40 and 227 +/- 55 hairs cm(-2), respectively). African hair grew at a much slower rate than caucasian hair (mean +/- SD 256 +/- 44 vs. 396 +/- 55 microm day(-1)), and telogen counts were frequently higher in African hair (mean +/- SD 18 +/- 9% vs. 14 +/- 11%).
This study demonstrated significant differences between African and caucasian hair growth parameters, which might suggest a trend towards increased hair loss in Africans, even though it contrasts with a lower and slower incidence of the development of alopecia in Africans.
Hair loss is a common problem that challenges the patient and clinician with a host of cosmetic, psychological and medical issues. Alopecia occurs in both men and women, and in all racial and ethnic populations, but the etiology varies considerably from group to group. In black women, many forms of alopecia are associated with hair-care practices (e.g., traction alopecia, trichorrhexis nodosa, and central centrifugal cicatricial alopecia). The use of thermal or chemical hair straightening, and hair braiding or weaving are examples of styling techniques that place African American women at high risk for various "traumatic" alopecias. Although the exact cause of these alopecias is unknown, a multifactorial etiology including both genetic and environmental factors is suspected. A careful history and physical examination, together with an acute sensitivity to the patient's perceptions (e.g., self-esteem and social problems), are critical in determining the best therapy course. Therapeutic options for these patients range from alteration of current hair grooming practices or products, to use of specific medical treatments, to hair replacement surgery. Since early intervention is often a key to preventing irreversible alopecia, the purpose of the present article is to educate the dermatologist on all aspects of therapy for hair loss in black women--including not only a discussion of the main medical and surgical therapies but also an overview of ethnic hair cosmetics, specific suggestions for alterations of hair-care practices, and recommendations for patient education and compliance.
Three subjects with virgin African hair combed daily had surprisingly short hair length measurements of 40.1 +/- 14 mm, 60 +/- 10 mm, and 69 +/- 20 mm at 6 months, 1 year, and 3 years after a haircut, respectively. This observation raises the possibility that combing African hair on a daily basis may result in the equivalent of a daily haircut in some people. This observation is based on few participants and will require confirmation in population studies.
Anecdotal reports suggest that certain disorders are common in African hair and may be associated with hairstyles.
A cross-sectional study of 1042 schoolchildren was performed to test this hypothesis.
A questionnaire was administered and scalp examinations performed, after ethics approval.
Participants included 45% boys and 55% girls. The majority of boys, 72.8%, kept natural hair with frequent haircuts (within 4 weeks). The prevalence of acne (folliculitis) keloidalis nuchae (AKN) was 0.67% in the whole group and highest (4.7%) in boys in the final year of high school, all of whom had frequent haircuts. The majority of girls (78.4%) had chemically relaxed hair, which was usually combed back or tied in ponytails, vs. 8.6% of boys. Traction alopecia (TA) was significantly more common with relaxed than natural hair, with an overall prevalence of 9.4% (98 of 1042) and of 17.1% in girls, in whom it increased with age from 8.6% in the first year of school to 21.7% in the last year of high school. The proportion with TA in participants with a history of braids on natural hair was lower (22.9%), but not significantly, than among those with a history of braids on relaxed hair (32.1%). No cases of central centrifugal cicatricial alopecia were identified.
We found associations between hairstyle and disease in our population of schoolchildren. AKN appears to be associated with frequently cut natural hair and TA with relaxed hair. These associations need further study for purposes of disease prevention.
Anecdotal reports suggest that certain scalp disorders are common in Africans and may be associated with hairstyles.
This study of 874 African adults in Cape Town was performed to test this hypothesis.
A questionnaire was administered and scalp examinations performed, after ethics approval.
Participants included 30.9% men and 69.1% women (median age 36.1 years, range 18-99). Most men had natural hair: 91.7% vs. 24.3% women. The majority of men had recent haircuts (< 4 weeks): 74.8% vs. 9.9% women. The overall prevalence of acne (folliculitis) keloidalis nuchae (AKN) was 3.5%: higher in men than women (10.5% vs. 0.3%). AKN prevalence was not associated with whether clippers or blades were used. However, it was associated with haircut symptoms. Haircut-associated symptoms, i.e. at least one episode of transient pimples (or crusts) and bleeding (however small) were reported in 37% and 18.9% of men, respectively. The latter may have implications for disease transmission. Most women (58.7%) had chemically treated hair (49.2% relaxed and 9.6% permed hair) vs. 2.3% men. The prevalences of traction alopecia (TA) and central centrifugal cicatricial alopecia (CCCA) were 22.6% and 1.9%: higher in women (31.7% vs. 2.2% and 2.7% vs. 0%, respectively). CCCA was highest in women > 50 years (6.7% vs. 1.2%). TA prevalence was highest if the usual hairstyle was extensions attached to relaxed hair (48%).
We found associations between specific scalp diseases, hairstyles, gender, and age. These associations need further study, better to elucidate determinants and to improve disease prevention and treatment.
The natural hair movement
- Wilkerson K.
Cosmetics & Tioletries Magazine
- T. A. Evans
The effect of hair relaxer treatment of amino acid profile and surface characteristics of South Africa Negroid Hair
- T. M. Mamabolo
Effect of Chemistry and Humectant treatments on the Mechanical and Fractographic behaviour of Negroid hair
- Y. K. Kamath
- S. B. Hornby
- H. Weignmann