“…There are quite a few papers in the literature concerning hair coat analysis in various mammal species [Kneberg, 1935;Rosen, 1974;Bakuneeta et al, 1993;Sahajpal et al, 2008;De et al, 2009;Sahajpal et al, 2009;Sarkar et al, 2010Sarkar et al, , 2011Gharu and Trivedi, 2013]; however, the authors mainly focused on the hair of animals used in the fur trade, especially in terms of usefulness for fur garment production [Przysiecki et al, 2009;Nowicki et al, 2012]. This study found that the thickness of hair from the study species was in the range of 35-95 µm, and this thickness may be compared to the thickness of the hairs of most mammal species [Debelica and Thies, 2009] including humans [Chernova, 2014].…”
Section: Discussionmentioning
confidence: 99%
“…Macroscopic examination of the hair provides morphological features of hair structure such as colour, gloss, length, elongation or flexibility, while microscopic analyses involve examinations using a scanning electron microscope (SEM) allowing the description of particular hair layers, e.g. scale numbers on sheath areas [Kneberg, 1935;Broeck et al, 2012]. The aim of this study was an evaluation of hairs derived from the heads of adult females of lar gibbon, crested black macaque and common chimpanzee in order to determine their physicomechanical and histological features.…”
The aim of this study was to determine selected characteristics of hair originating from adult females of three primate species: lar gibbon, crested black macaque and common chimpanzee. The research material consisted of 300 hairs collected from the top of the head. The analysis included the length, diameter, strength, breaking load, elongation and cross-section area of the hairs, and the hair index. Additionally, the scale number per 1 mm of hair length was determined using scanning electron microscope images. Lar gibbon hairs were the thinnest and the longest, while common chimpanzee hairs were the thickest and the shortest, and concurrently the least resistant. Hairs from various primate species differ in terms of their morphological structure and histological features and thus can be used for differentiation and identification of species.
“…There are quite a few papers in the literature concerning hair coat analysis in various mammal species [Kneberg, 1935;Rosen, 1974;Bakuneeta et al, 1993;Sahajpal et al, 2008;De et al, 2009;Sahajpal et al, 2009;Sarkar et al, 2010Sarkar et al, , 2011Gharu and Trivedi, 2013]; however, the authors mainly focused on the hair of animals used in the fur trade, especially in terms of usefulness for fur garment production [Przysiecki et al, 2009;Nowicki et al, 2012]. This study found that the thickness of hair from the study species was in the range of 35-95 µm, and this thickness may be compared to the thickness of the hairs of most mammal species [Debelica and Thies, 2009] including humans [Chernova, 2014].…”
Section: Discussionmentioning
confidence: 99%
“…Macroscopic examination of the hair provides morphological features of hair structure such as colour, gloss, length, elongation or flexibility, while microscopic analyses involve examinations using a scanning electron microscope (SEM) allowing the description of particular hair layers, e.g. scale numbers on sheath areas [Kneberg, 1935;Broeck et al, 2012]. The aim of this study was an evaluation of hairs derived from the heads of adult females of lar gibbon, crested black macaque and common chimpanzee in order to determine their physicomechanical and histological features.…”
The aim of this study was to determine selected characteristics of hair originating from adult females of three primate species: lar gibbon, crested black macaque and common chimpanzee. The research material consisted of 300 hairs collected from the top of the head. The analysis included the length, diameter, strength, breaking load, elongation and cross-section area of the hairs, and the hair index. Additionally, the scale number per 1 mm of hair length was determined using scanning electron microscope images. Lar gibbon hairs were the thinnest and the longest, while common chimpanzee hairs were the thickest and the shortest, and concurrently the least resistant. Hairs from various primate species differ in terms of their morphological structure and histological features and thus can be used for differentiation and identification of species.
“…A). In humans, kidney‐like hair cross sections have been commonly associated with pili‐torti, but they also occur in non‐pathological contexts (Pruner‐Bey, ; Kneberg, ; Mirmirani, Samimi & Mostov, ).…”
Section: Hair Curvature: Mechanical and Morphological Considerationsmentioning
confidence: 99%
“…[Sources: A, Kassenbeck (); B1 , Bryson et al . (), adapted and reprinted with permission of authors; B2, Kneberg (); B3, Da Cunha Filho et al . (), reprinted with permission of authors and Anais Brasileiros de Dermatologia; C, adapted from Dry (, figs 100a, b)].…”
Section: Hair Curvature: Mechanical and Morphological Considerationsmentioning
confidence: 99%
“…Among races, EI values greater than 1.7 are usually associated with highly curved/frizzled African hair, those of 1.2 or less with straight Asian hair, and values between with wavy European hair. However, EIs represent a continuum and overlap considerably among races and even within individuals (Kneberg, ; Hooton, ). Increased separation between MPC could account for increasingly divergent hair‐cord growth rates, thus twisting, while simultaneously rendering the process stochastic rather than deterministic.…”
Section: Hair Curvature: Mechanical and Morphological Considerationsmentioning
Although hair forms (straight, curly, wavy, etc.) are present in apparently infinite variations, each fibre can be reduced to a finite sequence of tandem segments of just three types: straight, bent/curly, or twisted. Hair forms can thus be regarded as resulting from genetic pathways that induce, reverse or modulate these basic curvature modes. However, physical interconversions between twists and curls demonstrate that strict one-to-one correspondences between them and their genetic causes do not exist. Current hair-curvature theories do not distinguish between bending and twisting mechanisms. We here introduce a multiple papillary centres (MPC) model which is particularly suitable to explain twisting. The model combines previously known features of hair cross-sectional morphology with partially/completely separated dermal papillae within single follicles, and requires such papillae to induce differential growth rates of hair cortical material in their immediate neighbourhoods. The MPC model can further help to explain other, poorly understood, aspects of hair growth and morphology. Separate bending and twisting mechanisms would be preferentially affected at the major or minor ellipsoidal sides of fibres, respectively, and together they exhaust the possibilities for influencing hair-form phenotypes. As such they suggest dialectic for hair-curvature development. We define a natural-dialectic (ND) which could take advantage of speculative aspects of dialectic, but would verify its input data and results by experimental methods. We use this as a top-down approach to first define routes by which hair bending or twisting may be brought about and then review evidence in support of such routes. In particular we consider the wingless (Wnt) and mammalian target of rapamycin (mTOR) pathways as paradigm pathways for molecular hair bending and twisting mechanisms, respectively. In addition to the Wnt canonical pathway, the Wnt/Ca(2+) and planar cell polarity (PCP) pathways, and others, can explain many alternatives and specific variations of hair bending phenotypes. Mechanisms for hair papilla budding or its division by bisection or fission can explain MPC formation. Epithelial-to-mesenchymal (EMT) and mesenchymal-to-epithelial (MET) transitions, acting in collaboration with epithelial-mesenchymal communications are also considered as mechanisms affecting hair growth and its bending and twisting. These may be treated as sub-mechanisms of an overall development from neural-crest stem cell (NCSC) lineages to differentiated hair follicle (HF) cell types, thus providing a unified framework for hair growth and development.
Woolly hair is very curly hair that is characteristically unruly and will not form naturally into locks. Woolly hair nevus first appears when the scalp hair begins to grow. It is seen as a patch of unruly, very curly hair, arising in a field of otherwise unremarkable scalp hair. Woolly hair can also be seen as a hereditary trait involving the entire scalp and in acquired forms. It may be distinguished from two other types of unruly hair, pili torti and spun glass hair.
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