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1
Nagase. "Hair Structures Affecting Hair Appearance." Cosmetics 6, no. 3 (July 11, 2019): 43. http://dx.doi.org/10.3390/cosmetics6030043.
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Optical factors affecting hair appearance are reviewed based on hair structures from macroscopic to microscopic viewpoints. Hair appearance is the result of optical events, such as reflection, refraction, scattering, and absorption. The effects of hair structures on such optical events are summarized and structural conditions for hair appearance are considered. Hair structures are classified into the following: the alignment of multiple hair fibers, the cross-sectional shape of the hair fiber, and the microstructures of hair fiber (cuticle, cortex, and medulla). The alignment of multiple hair fibers is easily affected by the existence of meandering fibers and their alignment along hair length becomes less-synchronized. The less-synchronized orientation of multiple fibers causes the broadening of the apparent reflection and luster-less dull impression. The cross-sectional shape of hair fiber affects light reflection behavior. Hair fibers with elliptical cross-section show glittering colored light based on total reflection in the hair. The scaly structures of cuticles at the surface of hair are often uplifted and cause light scattering, and then affect hair luster. The porous structure of the cortex and medulla in hair fiber can cause light scattering and affect hair luster and color. The above phenomena suggest that important factors for hair appearance are the alignment of multiple hair fibers, appropriate cross-sectional shape, ordered scaly structure, and pore-less internal structure.
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Prasad K., Eshwara, Divakara Rao P., and Udaya Kiran C. "Experimental Studies on Behavior of Keratin Based Human Hair Fiber - A New Reinforcing Material for Composites." International Journal of Engineering & Technology 7, no. 4.5 (September 22, 2018): 459. http://dx.doi.org/10.14419/ijet.v7i4.5.20207.
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Composite materials are formed by two or more constituents at macroscopic level. Type and form of fiber plays a vital role in imparting required properties to the composite. Many researchers contributed to the development of artificial fiber composites which are not environmental friendly in nature. Sizable research is also done in the area of natural fiber composites. Human hair is a non-biodegradable waste available in abundant quantity across the world, but is rarely explored for applications in engineering fields. In the present study, a review on behavior of human hair fibers was made to understand their suitability as a reinforcing material in composites. Morphology of the hair fibers is reviewed and the density of the hair fibers was determined using Archimedes principle. Tensile strength of the hair fibers is experimentally estimated. Chemical resistivity and burning tests were conducted. Tensile and flexural properties of hair fiber reinforced polyester composite were experimentally determined and compared.
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Starcher, Barry, Ronnie L. Aycock, and Charles H. Hill. "Multiple Roles for Elastic Fibers in the Skin." Journal of Histochemistry & Cytochemistry 53, no. 4 (April 2005): 431–43. http://dx.doi.org/10.1369/jhc.4a6484.2005.
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Dermal elastic fibers are believed to have a primary role in providing elastic stretch and recoil to the skin. Here we compare the structural arrangement of dermal elastic fibers of chick skin and different animal species. Most elastic fibers in chick skin are derived from cells that line the feather follicle and/or smooth muscle that connects the pterial and apterial muscle bundles to feather follicles. Elastic fibers in the dermis of animals with single, primary hair follicles are derived from cells lining the hair follicle or from the ends of the pili muscle, which anchors the muscle to the matrix or to the hair follicle. Each follicle is interconnected with elastic fibers. Follicles of animals with primary and secondary (wool) hair follicles are also interconnected by elastic fibers, yet only the elastic fibers derived from the primary follicle are connected to each primary follicle. Only the primary hair follicles are connected to the pili muscle. Human skin, but not the skin of other primates, is significantly different from other animals with respect to elastic fiber organization and probably cell of origin. The data suggest that the primary role for elastic fibers in animals, with the possible exception of humans, is movement and/or placement of feathers or hair.
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Li, Hui Qin, Ji Xian Gong, and Yi Zhang. "Characterization of Protein Powder from Waste Rabbit Hair." Advanced Materials Research 194-196 (February 2011): 407–10. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.407.
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Rabbit hair is an important animal fiber in China, making up 90% of the total output in the world. Fuds is one of familiar problems in the processing of rabbit hair, which lead to plenty of waste fibers. Recently, there has been interest in converting protein fibers into powder to develop their new uses. This provides great opportunities for waste rabbit hair. In this study, rabbit hair powders have been produced and the structure and properties were characterized at multi-level. Surface morphology of rabbit hair powders was observed by scanning electron microscopy (SEM) and the majority of rabbit hair powders appear to be small fibrous particles. The FTIR spectrum of rabbit hair and rabbit hair powders was detected. Although no new chemical bonds were produced in the rabbit hair powders, the result showed that some absorbing peaks of rabbit hair powder become stronger than that of rabbit hair. Absorption of rabbit hair powders was also investigated. The result showed that rabbit hair powder had higher moisture retention rate than that of rabbit hair, wool fiber and cotton fiber. Moreover, rabbit hair powder showed remarkable sorption ability for metal ions. The characterization of rabbit hair powder will provide useful basal data for the further application of rabbit hair in novel areas.
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Ma, Yun Hai, Bao Gang Wang, Sheng Long Shen, Xue Ying Geng, Hong Lei Jia, and Shuang Wen. "Effects of Hair Fibers on Braking Friction Materials." Advanced Materials Research 399-401 (November 2011): 1725–28. http://dx.doi.org/10.4028/www.scientific.net/amr.399-401.1725.
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In this experiment, the effects of hair fibers on friction and wear property, Rockwell hardness and impact strength of friction materials were examined. The results showed that friction coefficient increases and stabilizes and specific wear rates were decrease as the hair fibers were filled and, particularly, 1% of the hair fiber content had a significant effect in the friction material. As temperature was changed, the stability of the friction coefficient of friction materials can be improved, the Rockwell hardness decrease and the impact strengths increase by way of increasing the content of hair fibers. The worn surfaces of friction materials were examined by scanning electron microscopy and wear mechanisms were analyzed. So it’s a kind of quite good non-asbestos friction material.
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Koerber, H. R., and L. M. Mendell. "Functional specialization of central projections from identified primary afferent fibers." Journal of Neurophysiology 60, no. 5 (November 1, 1988): 1597–614. http://dx.doi.org/10.1152/jn.1988.60.5.1597.
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1. Somata of primary afferent fibers were impaled in the L7 or S1 dorsal root ganglion in cats anesthetized with alpha-chloralose. Individual cells (n = 182) were characterized according to receptive field (RF) and by the peripheral mechanoreceptor they innervated. They were then stimulated intracellularly while recording the evoked cord dorsum potentials (CDPs) simultaneously at four sites. CDPs were recorded in response to single fiber stimulation while varying both the frequency and the numbers of action potentials (APs) evoked per trial. Stimulus parameters included: 1) single APs evoked at both high (18 Hz) and low (0.67 Hz) frequencies, 2) pairs of APs (50-ms ISI) delivered at 0.67 Hz, and 3) trains of four APs (20-ms ISI) also delivered at 0.67 Hz. The properties of the CDPs and their relationship to receptor type innervated by the fiber were determined. 2. CDPs evoked by 18-Hz stimulation consisted of an axon fiber spike followed at a short latency [600 +/- 9.9 (SEM) microseconds] by the onset of a monophasic negative wave. A-beta-afferent fibers innervating slowly adapting type 1 and 2 receptors (SA1 and SA2) evoked the largest amplitude CDPs followed by field and hair follicle afferents while A-delta-fibers rarely produced measurable CDPs at this frequency of stimulation. 3. The magnitude of the CDP varied at the four recording sites with clear evidence in individual experiments that the projections of individual fibers are somatotopically organized. 4. CDPs evoked by 0.67-Hz stimulation had the same onset latency but were larger in amplitude and had longer time-to-peak and durations than those elicited by high frequency stimulation. Under these conditions A-beta-fibers innervating hair follicles produced the largest CDPs followed by field receptors and SA1s and SA2s. A-beta- and A-delta-fibers innervating high threshold mechanoreceptors (HTMRs) and A-delta-fibers innervating down hair follicles (D-hairs) produced CDPs of amplitude and duration similar to those evoked by slower A-beta-fibers. 5. The response to a test stimulus delivered 50 ms after a conditioning stimulus to the same single fiber was always depressed in the case of A-beta-fibers supplying rapidly adapting receptors. The conditioning stimulus exerted relatively little effect on the response to the test stimulus for A-beta- fibers innervating slowly adapting receptors. The test response to stimulation of A-beta- and A-delta- fibers innervating HTMRs was consistently facilitated while stimulation of A-delta- D-hairs evoked either marked facilitation or slight depression.(ABSTRACT TRUNCATED AT 400 WORDS)
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Yongfu, Xu, and Yi Zhang. "Study on modification of rabbit hair fibers with L-cysteine." Textile Research Journal 90, no. 13-14 (December 3, 2019): 1628–38. http://dx.doi.org/10.1177/0040517519891449.
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Rabbit hair fibers were modified by L-cystine under the action of ultrasound and a kind of modified rabbit hair fiber was obtained. An orthogonal test of four factors and three levels was designed. The range analysis was analyzed using a comprehensive score method of friction factor and fiber strength, and the variance analysis was carried out by Statistical Package for Social Science statistical software. The optimal modification conditions were obtained: a concentration of L-cystine (A) of 0.05 mol/L, ultrasonic power (B) of 90 W, a water bath temperature (C) of 75℃, and ultrasonic treatment time (D) of 1 hour. Univariate analysis showed the L-cystine concentration had the most significant effect on the modification of rabbit hair fibers, and the regression equation is y = 74.423 + 1300.267 A−1.818 C−9092A2 + 0.019C2. The surface brightness of the modified rabbit hair fibers was enhanced and the scale angle was increased 20° by setting up the angle of the scale model and the electron microscope. The internal structure of rabbit hair fibers was characterized by Fourier transform infrared spectroscopy, peak separation, and differential scanning calorimetry. The results showed that L-cystine reduced the disulfide bond in the macromolecular chain by 3%, resulting in a change in the secondary structure of the rabbit hair, a decrease in the α-helix structure content, and an increase in β-folding structure content. Ellman’s reagent was used to determine that the content of the sulfhydryl group consumed in the modification was 0.211 mol/L. Testing the dye adsorption capacity and spinnability (adding 20%) of modified rabbit hair fibers showed an obvious improvement.
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Bradley, David. "Hair-thin OLED fibers." Materials Today 21, no. 4 (May 2018): 319–20. http://dx.doi.org/10.1016/j.mattod.2018.03.021.
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Wright, Darin L., Richard R. Gacek, and Joanne E. Schoonmaker. "Fiber Grouping in the Feline Vestibular Nerve before and after Labyrinthectomy." Annals of Otology, Rhinology & Laryngology 107, no. 3 (March 1998): 207–12. http://dx.doi.org/10.1177/000348949810700304.
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The vestibular nerve is composed of fibers with a wide spectrum of diameters. The fibers of largest diameter are known to innervate the type I hair cells of the cristae, while the small-diameter fibers innervate the type II hair cells. Midsized fibers (dimorphic fibers) represent neurons that innervate both type I and type II hair cells. Reports by others have commented on the tendency for clustering of fibers with like diameters. Rigorous statistical proof for or against clustering has not yet been presented. The explanation for this is, in part, the mathematic complexity of analyzing clustering in a system composed of three elements. We report a new method for analysis of fiber clustering and apply this method to large-, medium-, and small-diameter fibers in the feline vestibular nerve. The fiber grouping in the caudal and rostral ends of the vestibular nerves of six normal animals is compared to that in similar areas of the nerves of five animals 12 to 17 months after unilateral labyrinthectomy. No statistically significant clustering of fiber types was found in the rostral portion of either the control or the labyrinthectomized animals. In the caudal portion of the control nerves, clustering of the large fibers was demonstrated (p <.005, χ2 test). This clustering was not demonstrated after labyrinthectomy. An explanation of these findings is discussed. The method used in this study to analyze fiber clustering may be applicable to other nerve systems of greater complexity.
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Gurkan Unal, Pelin, and Rıza Atav. "Determination of the relationship between fiber characteristics and felting tendency of luxury fibers from various origins." Textile Research Journal 88, no. 6 (January 6, 2017): 636–43. http://dx.doi.org/10.1177/0040517516685282.
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When literature is reviewed in detail, it can be seen that there is limited research, especially on Angora rabbit fiber and again in none of the research was the felting propensity of luxury protein fibers from different origins (goat, camelid and rabbit) related with fiber properties, such as cuticle scale frequency and scale height. For this purpose, hair-based luxury fibers, which are most widely used and consumed all over the world (cashmere, mohair, angora, Huacaya alpaca and Suri alpaca) were chosen in order to measure fiber diameter, fiber length, cuticle scale frequency and scale height of these fibers. As a result, detailed relations about the felting propensity of the hair-based luxury fibers with the fiber properties were investigated. According to the experimental analysis, it was determined that angora, which is the finest and the shortest animal fiber, showed the lowest felting propensity. On the other hand, Suri alpaca fiber with a low scale height gave the highest feltability due to being the longest among the investigated fibers.
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Wang, Wendi, Guangjing Liu, Man Liu, and Xiaobing Li. "Mechanisms underlying the action of self-assembling short-peptide nano-fiber gel scaffold materials in the aesthetic repair of burn wounds." Materials Express 10, no. 3 (March 1, 2020): 454–59. http://dx.doi.org/10.1166/mex.2020.1640.
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To study the mechanism of self-assembling short-peptide nano-fiber gel scaffolds on the aesthetic repair of burns. RADA16-1 assembled short-peptide nano-fiber gel scaffold was prepared using the ultrasonic method. Twenty female SD rats were randomly divided into two groups. Burn model was established using the electrical machinery method. The wound surface of the rats in the experimental group was coated with RADA16-1 and that of the rats in the control group was coated with NaCl. The degree of wound healing, hair follicle growth, hair growth length, and expression of bFGF and EGF were compared between the two groups. RADA16-1 fibers were broken into short fibers under the ultrasonic environment and then reorganized into gels. The degree of wound healing, hair follicle growth, hair growth length, and expression of bFGF and EGF in the experimental group were better than those in the control group. The assembly of short peptide nano-fiber gel scaffolds can effectively repair burn wounds.
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Araya-Letelier, Gerardo, Federico C. Antico, Pablo Fernado Parra, and Miguel Carrasco. "Fiber-Reinforced Mortar Incorporating Pig Hair." Advanced Engineering Forum 21 (March 2017): 219–25. http://dx.doi.org/10.4028/www.scientific.net/aef.21.219.
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Recycled fibers from food-industry could be added as reinforcement to cement-based materials. Cement-based materials perform well under compression, but tensile strength and post-cracking ductility in tension are poor. Fibers produced from steel, glass and synthetic materials, have been successfully used to overcome some of these shortcomings. Fiber-reinforced mortar has shown an increased post-cracking ductility and improved long-term serviceability due to the crack control provided by fibers. Food-industry waste disposal is globally a major concern because of its environmental impacts. For these reasons, the use of recycled materials in construction applications has been investigated over the last decades. This investigation deals with the incorporation of pig hair, which is a waste produced by the food-industry worldwide, in fiber-reinforced mortars. This composite material is intended to reduce the environmental impacts by valuing waste materials in construction applications while improving mechanical properties. To determine compressive, flexural and impact strength, bulk density, porosity and dynamic modulus of elasticity laboratory tests were conducted in mortar specimens with 0%, and 2% of pig-hair content in weight of cement. The results of this research show that the impact strength can increase up to five times when compared to plain mortar. Moreover, the compressive and flexural strengths, bulk density, porosity and the dynamic modulus of elasticity of fiber-reinforced mortar, with the aforementioned pig-hair content, are not significantly affected.
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Wang, Zongqian, Dengfeng Wang, Mingrong Wang, Wei Li, and Qing Sui. "Metaplexis japonicaseed hair fiber: a member of natural hollow fibers and its characterization." Textile Research Journal 89, no. 21-22 (March 7, 2019): 4363–72. http://dx.doi.org/10.1177/0040517519834600.
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Metaplexis japonica seed hair fibers (Mj-fiber), harvested from the seed pods of Metaplexis japonica (Apocynaceae: Asclepiadoideae) originating in China, Japan and Korea, have features ensuring its potential application in the textile and other industrial fields. In spite of the extensive study on the medicinal properties of Metaplexis japonica, research literature about Mj-fiber is quite limited. We obtained Mj-fibers by artificial peeling and seed removing; then the fiber morphology, chemical composition, structures, fiber surface absorption characteristics, and tensile and thermal properties were studied in detail. From the results, Mj-fiber has a hollow structure with a thin fiber wall and large lumen, in which the hollowness is over 92%. Uniquely, Mj-fiber is a natural profiled fiber with a cross-section of a "cross flower" morphology. At the same time, the density of it is very low, accounting for only one-fifth of the cotton fibers, and the fiber length distribution is relatively concentrated. The main component is cellulose, with a content of 53.9 ± 3.20% and structure of cellulose I. In particular, Mj-fiber has excellent hydrophobic and oil affinity surface characteristics. Moreover, the fibers bulkiness and warmth retention performance are comparable to that of duck down. Therefore, the results provide an experimental basis for the application of Mj-fibers in the textile and other industrial fields.
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Liu, Jian. "Analysis for Stress-Strain Curve during Stretching Coarse Yak Hair with Different Pretreating Condition." Advanced Materials Research 535-537 (June 2012): 1112–15. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.1112.
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The changes, on stress-strain curve of coarse yak hair piece with different pretreating condition, have been analyzed during stretching slenderization in this paper. The result shows that the reagent of pretreatment could break the S-S bond effectively to prepare for stretching, and the pretreatment reagent will damage the structure of yak hair fiber if the pretreating time is more than 10min. From curve analysis, it shows that the stretching speed raising will cause the strengthening point brought forward and the yak hair fiber will bear more action force when stretching, and slow stretching could reduce the damage effectively to the structure of yak hair fiber. In addition, part of fibers would have some slippage or breakage on yak hair pieces when stretching slenderization happen.
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Zhang, Yi, Qiu Ting Zheng, Xiao Qing Wang, and Hua Wu Liu. "Structure Structural Characteristics of Rabbit Hair." Advanced Materials Research 332-334 (September 2011): 1073–76. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.1073.
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Key morphological features of rabbit hair were investigated and compared with these of cashmere fiber. When the rabbit fiber diameter was about 10um, the angle of scale edge to the fiber axis was small. When the fiber diameter was around 40um, scale edges inclined larger angles to the axis. In addition, no overlapping and checks along the scale edges were observed in such coarse hair. The rabbit fiber diameters were normally between 10um and 20um and the scales of these fibers were long strip shaped with sharp tip at the middle. There was obvious boundary in the cashmere fiber after dyeing. One side is far darker than the other. On the contrast, this bilateral structure was not observed in the rabbit hair samples. The cortical cells presented in an uneven distribution in the rabbit hair. The mean ratio of medulla (filled with plenty of air) to fiber diameter was about 40%, which provide excellent thermal insulation to the rabbit hair assemblies.
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Takahashi, Toshie. "Unique Hair Properties that Emerge from Combinations of Multiple Races." Cosmetics 6, no. 2 (June 21, 2019): 36. http://dx.doi.org/10.3390/cosmetics6020036.
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The fusion of ethnicity in human populations is becoming increasingly common, so the conventional definition of ethnicity is going to become deficient. The aim of this study was to investigate the hair properties which emerge from combinations of multiple races. Hair fibers collected from mixed-race subjects were investigated and classifications of hair shape as well as measurements of thickness, ellipticity and surface damage were carried out. The results show that hair shapes varied widely: straight hair and very curly hair often existed together on the heads of individuals with mixed ethnicity. Curly hair tended to be thicker than loose wavy hair. As for damage to the hair surface, the hairs of mixed-race subjects showed a very unique property in that they were much more severely damaged near the root (the proximal end) than the hairs of monoracial subjects. The hair shape (curly or loose wavy) was not related to the level of damage. The severe damage near the proximal end is thought to be caused by entanglement, due to the presence of various curl phases. This study reports the unique characteristics of hairs of subjects with mixed ethnicity, which have never been noted in the previous studies on subjects with a monoracial background.
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Fernandez, C., A. Lysakowski, and J. M. Goldberg. "Hair-cell counts and afferent innervation patterns in the cristae ampullares of the squirrel monkey with a comparison to the chinchilla." Journal of Neurophysiology 73, no. 3 (March 1, 1995): 1253–69. http://dx.doi.org/10.1152/jn.1995.73.3.1253.
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1. The numbers of type I and type II hair cells were estimated by dissector techniques applied to semithin, stained sections of the horizontal, superior, and posterior cristae in the squirrel monkey and the chinchilla. 2. The crista in each species was divided into concentrically arranged central, intermediate, and peripheral zones of equal areas. The three zones can be distinguished by the sizes of individual hair cells and calyx endings, by the density of hair cells, and by the relative frequency of calyx endings innervating single or multiple type I hair cells. 3. In the monkey crista, type I hair cells outnumber type II hair cells by a ratio of almost 3:1. The ratio decreases from 4-5:1 in the central and intermediate zones to under 2:1 in the peripheral zone. For the chinchilla, the ratio is near 1:1 for the entire crista and decreases only slightly between the central and peripheral zones. 4. Nerve fibers supplying the cristae in the squirrel monkey were labeled by extracellular injections of horseradish peroxidase (HRP) into the vestibular nerve. Peripheral terminations of individual fibers were reconstructed and related to the zones of the cristae they innervated and to the sizes of their parent axons. Results were similar for the horizontal, superior, and posterior cristae. 5. Axons seldom bifurcate below the neuroepithelium. Most fibers begin branching shortly after crossing the basement membrane. Their terminal arbors are compact, usually extending no more than 50-100 microns from the parent exon. A small number of long intraepithelial fibers enter the intermediate and peripheral zones of the cristae near its base, then run unbranched for long distances through the neuroepithelium to reach the central zone. 6. There are three classes of afferent fibers innervating the monkey crista. Calyx fibers terminate exclusively on type I hair cells, and bouton fibers end only on type II hair cells. Dimorphic fibers provide a mixed innervation, including calyx endings to type I hair cells and bouton endings to type II hair cells. Long intraepithelial fibers are calyx and dimorphic units, whose terminal fields are similar to those of other fibers. The central zone is innervated by calyx and dimorphic fibers; the peripheral zone, by bouton and dimorphic fibers; and the intermediate zone, by all three kinds of fibers. Internal (axon) diameters are largest for calyx fibers and smallest for bouton fibers. Of the entire sample of 286 labeled fibers, 52% were dimorphic units, 40% were calyx units, and 8% were bouton units.(ABSTRACT TRUNCATED AT 400 WORDS)
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Keough, R., B. Powell, and G. Rogers. "Targeted expression of SV40 T antigen in the hair follicle of transgenic mice produces an aberrant hair phenotype." Journal of Cell Science 108, no. 3 (March 1, 1995): 957–66. http://dx.doi.org/10.1242/jcs.108.3.957.
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Directed expression of SV40 large T antigen (TAg) in transgenic mice can induce tissue-specific tumorigenesis and useful cell lines exhibiting differentiated characteristics can be established from resultant tumor cells. In an attempt to produce an immortalised mouse hair follicle cortical cell line for the study of hair keratin gene control, SV40 TAg expression was targeted to the hair follicles of transgenic mice using a sheep hair gene promoter. Expression of SV40 TAg in the follicle cortex disrupted normal fiber ultrastructure, producing a marked phenotypic effect. Affected hairs were wavy or severely kinked (depending on the severity of the phenotype) producing an appearance ranging from a ruffled coat to a stubble covering the back of the mouse. The transgenic hairs appeared to be weakened at the base of the fibers, leading to premature hair-loss and a thinner pelage, or regions of temporary nudity. No follicle tumors or neoplasia were apparent and immortalisation of cortical cells could not be established in culture. In situ hybridisation studies in the hair follicle using histone H3 as a cell proliferation marker suggested that cell proliferation had ceased prior to commencement of K2.10-TAg expression and was not re-established in the differentiating cortical cells. Hence, TAg was unable to induce cell immortalisation at that stage of cortical cell differentiation. However, transgenic mice developed various other abnormalities including vertebral abnormalities and bladder, liver and intestinal tumors, which resulted in reduced life expectancy.
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Velasco, Maria Valéria Robles, Tania Cristina de Sá Dias, Anderson Zanardi de Freitas, Nilson Dias Vieira Júnior, Claudinéia Aparecida Sales de Oliveira Pinto, Telma Mary Kaneko, and André Rolim Baby. "Hair fiber characteristics and methods to evaluate hair physical and mechanical properties." Brazilian Journal of Pharmaceutical Sciences 45, no. 1 (March 2009): 153–62. http://dx.doi.org/10.1590/s1984-82502009000100019.
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The hair thread is a natural fiber formed by keratin, a protein containing high concentration of sulfur coming from the amino acid cystine. The main physical proprieties of the hair depend mostly on its geometry; the physical and mechanical properties of hair involve characteristics to improve: elasticity, smoothness, volume, shine, and softness due to both the significant adherence of the cuticle scales and the movement control (malleability), as well as the easiness of combing, since they reduce the fibers static electricity. The evaluation of these effects on hair may be carried out by several methods, as: optical and electron microscopy, mechanical resistance measuring, shine evaluation and optical coherence tomography (OCT).
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Harizi, T., S. Dhouib, S. Msahli, and F. Sakli. "Bleaching Process Investigation of Tunisian Dromedary Hair." ISRN Textiles 2013 (June 4, 2013): 1–5. http://dx.doi.org/10.1155/2013/532396.
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Successful bleaching of pigmented fibres was, generally, evaluated by a maximum whiteness, a minimum yellowness, and less damage to the bleached fibers. A review of the literature reveals that many studies on pigmented fibre bleaching are concerned with improving the whiteness and mechanical properties of bleached fibres. In this study, we investigate the effects of the hydrogen peroxide concentration, bleaching time, and clarification bath on the bleaching efficiency of Tunisian dromedary hair. It was showed that 30 min bleaching time gives better result in term of whiteness. However, an increased bleaching time gives an excessive damage to the bleached fibers. Further, the damage incurred by the dromedary hair was more important than that for wool, as is shown by the tenacity results. We found that oxalic acid, which is used for rinsing dromedary hair (after bleaching), provides improved results in term of whiteness obtained with bleaching. Certainly, oxalic acid made it possible to remove the maximum of iron remaining on fibre after bleaching. Bleaching methods demonstrate the excessive damage incurred by the fibre when using hydrogen peroxide particularly with raise concentration. This damage leads to adverse effects on the tenacity fibre.
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Thanon Dawood, Eethar, and Mafaz Hani Abdullah. "Behavior of non-reinforced and reinforced green mortar with fibers." Open Engineering 11, no. 1 (November 19, 2020): 67–84. http://dx.doi.org/10.1515/eng-2021-0006.
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AbstractThe behavior of non-reinforced green mortar with fibers has been observed. Different green mortar mixes have been prepared using different percentages of waste glass powder (WGP), steel slag (SG) and silica fume (SF).The properties of flow, density, ultrasonic pulse velocity (UPV), compressive and flexural strengths have been tested for such green mortar in the first phase of the experimental work. The selected green mortar mix that gives good properties with the acceptable ranges of cement replacement by such cementitious materials has been utilized to achieve the second phase of the experimental work. Thus, the uses of human hair fibers, sisal fibers and stainless steel nails fibers in the form of individual and hybrid fibers system and testing for the same properties mentioned above have been performed. The third phase includes the cost estimation for the said mortar. Whereas, the last phase deals with analysis of the results using the integrated AHP and TOPSIS method for selection the best performance of the green mortar. The results of mono sisal fiber, human hair fiber and stainless nails fiber by 0.75, 0.75 and 2% of volume fraction respectively, exhibited the highest increase in compressive strength, flexural strength, UPV and density compared with other percentages.
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Yang, Qian. "Effect of Temperature and Humidity on Mechanical Properties of Rabbit Hair Fibers." Advanced Materials Research 573-574 (October 2012): 1230–34. http://dx.doi.org/10.4028/www.scientific.net/amr.573-574.1230.
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In this paper, it tests the mechanical properties of rabbit hair fibers in different temperatures and humidity. Contrast and analysis by experiment showed the temperature exerts a great influence on the tensile strain, breaking elongation, breaking force and breaking strength. In wetting condition, the tensile strain and breaking elongation increase, but the breaking force and breaking strength decrease. The rabbit hair fiber processing with too much water will make the structure easier to break and destroy.
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Khungurn, Pramook, and Steve Marschner. "Azimuthal Scattering from Elliptical Hair Fibers." ACM Transactions on Graphics 36, no. 2 (April 21, 2017): 1–23. http://dx.doi.org/10.1145/2998578.
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Dankovich, T. A., Y. K. Kamath, and S. Ruetsch. "Tensile properties of twisted hair fibers." International Journal of Cosmetic Science 27, no. 2 (April 2005): 138. http://dx.doi.org/10.1111/j.1467-2494.2005.00257_8.x.
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Marschner, Stephen R., Henrik Wann Jensen, Mike Cammarano, Steve Worley, and Pat Hanrahan. "Light scattering from human hair fibers." ACM Transactions on Graphics 22, no. 3 (July 2003): 780–91. http://dx.doi.org/10.1145/882262.882345.
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Tiedemann, Erica J., and Yiqi Yang. "Fiber-Safe Extraction of Red Mordant Dyes from Hair Fibers." Journal of the American Institute for Conservation 34, no. 3 (1995): 195. http://dx.doi.org/10.2307/3179540.
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Tiedemann, Erica J., and Yiqi Yang. "Fiber-Safe Extraction of Red Mordant Dyes from Hair Fibers." Journal of the American Institute for Conservation 34, no. 3 (January 1995): 195–206. http://dx.doi.org/10.1179/019713695806124657.
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Qualls, Clifford, Raffaella Bianucci, Michael N. Spilde, Genevieve Phillips, Cecilia Wu, and Otto Appenzeller. "Modeling Clinical States and Metabolic Rhythms in Bioarcheology." BioMed Research International 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/818724.
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Bioarcheology is cross disciplinary research encompassing the study of human remains. However, life’s activities have, up till now, eluded bioarcheological investigation. We hypothesized that growth lines in hair might archive the biologic rhythms, growth rate, and metabolism during life. Computational modeling predicted the physical appearance, derived from hair growth rate, biologic rhythms, and mental state for human remains from the Roman period. The width of repeat growth intervals (RI’s) on the hair, shown by confocal microscopy, allowed computation of time series of periodicities of the RI’s to model growth rates of the hairs. Our results are based on four hairs from controls yielding 212 data points and the RI’s of six cropped hairs from Zweeloo woman’s scalp yielding 504 data points. Hair growth was, ten times faster than normal consistent with hypertrichosis. Cantú syndrome consists of hypertrichosis, dyschondrosteosis, short stature, and cardiomegaly. Sympathetic activation and enhanced metabolic state suggesting arousal was also present. Two-photon microscopy visualized preserved portions of autonomic nerve fibers surrounding the hair bulb. Scanning electron microscopy found evidence that a knife was used to cut the hair three to five days before death. Thus computational modeling enabled the elucidation of life’s activities 2000 years after death in this individual with Cantu syndrome. This may have implications for archeology and forensic sciences.
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Koltzenburg, Martin, Cheryl L. Stucky, and Gary R. Lewin. "Receptive Properties of Mouse Sensory Neurons Innervating Hairy Skin." Journal of Neurophysiology 78, no. 4 (October 1, 1997): 1841–50. http://dx.doi.org/10.1152/jn.1997.78.4.1841.
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Koltzenburg, Martin, Cheryl L. Stucky, and Gary R. Lewin. Receptive properties of mouse sensory neurons innervating hairy skin. J. Neurophysiol. 78: 1841–1850, 1997. Using an in vitro nerve skin preparation and controlled mechanical or thermal stimuli, we analyzed the receptive properties of 277 mechanosensitive single primary afferents with myelinated ( n = 251) or unmyelinated ( n = 26) axons innervating the hairy skin in adult or 2-wk-old mice. Afferents were recorded from small filaments of either sural or saphenous nerves in an outbred mice strain or in the inbred Balb/c strain. On the basis of their receptive properties and conduction velocity, several receptor types could be distinguished. In adult animals (>6 wk old), 54% of the large myelinated fibers (Aβ, n = 83) showed rapidly adapting (RA) discharges to constant force stimuli and probably innervated hair follicles, whereas 46% displayed a slowly adapting (SA) response and probably innervated Merkel cells in touch domes. Among thin myelinated fibers (Aδ, n = 91), 34% were sensitive D hair receptors and 66% were high-threshold mechanoreceptors (AM fibers). Unmyelinated fibers had high mechanical thresholds and nociceptive functions. All receptor types had characteristic stimulus-response functions to suprathreshold force stimuli. Noxious heat stimuli (15-s ramp from 32 to 47°C measured at the corium side of the skin) excited 26% (5 of 19) of AM fibers with a threshold of 42.5 ± 1.4°C (mean ± SE) and an average discharge of 15.8 ± 9.7 action potentials and 41% (7 of 17) C fibers with a mean threshold of 37.6 ± 1.9°C and an average discharge of 22.0 ± 6.0 action potentials. Noxious cold stimuli activated 1 of 10 AM fibers and 3 of 10 C fibers. One of 10 C units responded to both heat and cold stimuli. All types of afferent fibers present in adult mice could readily be recognized in mice at postnatal day 14. However, fibers had reduced conduction velocities and the stimulus-response function to mechanical stimuli was more shallow in all fibers except for the D hairs. In juvenile mice, 22% of RA units also displayed an SA response at high stimulus intensities; these units were termed RA/SA units. We conclude that all types of cutaneous afferent fibers are already committed to their phenotype 2 wk after birth but undergo some maturation over the following weeks. This preparation has great potential for the study of transgenic mice with targeted mutations of genes that code factors that are involved in the specification of sensory neuron phenotypes.
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Mongush, S. S. "Wool productivity of ewes of different origin." Siberian Herald of Agricultural Science 50, no. 3 (July 26, 2020): 69–74. http://dx.doi.org/10.26898/0370-8799-2020-3-7.
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The article presents the results of the comparative study of sheep wool productivity of Tuva coarse-haired short-fat-tailed breed and the desired type of Tuva-Saradzha semi-coarse-haired breed. The study was conducted in 2018-2019 in the farms of the Republic of Tuva. For the experiment, two groups of ewes were formed: control (Tuva coarse-haired short-fat-tailed breed) and experimental (Tuva-Saradzha semi-coarse crossbreeds of the desired type). The study of the yield of pure fiber and the physical and technical properties of the wool were carried out according to generally accepted methods. During the study animals were in the same conditions of a year-round pasture management. The amount of wool shorn and the physical and technical properties of wool of Tuva-Saradzha cross-bred ewes and Tuva purebred short-fat-tailed ewes varied significantly. Tuva-Saradzha semi-coarse-haired ewes of the desired type exceeded their peers of Tuva region in terms of greasy wool shorn by 67.4%, and the yield of pure fiber – by 5.6%. When comparing different fractions of wool fibers in the hair of local semi-coarse ewes, the amount of beard hair was 3.3% less, and heterotype hair – 4.4% more than in the wool of Tuva ewes. The study of the fineness of wool fibers showed that in TuvaSaradzha ewes down and heterotype fibers were thicker (21.34; 57.45 μm), and beard hair was thinner (62.34 μm) compared to Tuva ewes. Sheep of semi-coarse breed had the longest hair. Research data on the physical and technical properties of wool of Tuva-Saradzha semi-coarse-haired ewes of the desired type demonstrated good prospects of the breed for the selection process.
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Fratto, Melanie A., and Andrew K. Davis. "Do black-furred animals compensate for high solar absorption with smaller hairs? A test with a polymorphic squirrel species." Current Zoology 57, no. 6 (December 1, 2011): 731–36. http://dx.doi.org/10.1093/czoolo/57.6.731.
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Abstract In polymorphic mammalian species that display multiple color forms, those with dark, or melanic pelage would be prone to overheating, especially if they live in warm climates, because their fur absorbs solar energy at a higher rate. However, experimental studies indicate that certain physical properties of fur of dark individuals appear to prevent, or minimize heat stress, although it is not clear what properties do so. Here, we tested the possibility that black-furred individuals simply have shorter or thinner hair fibers, which would create a lighter (in terms of weight) coat or one that allows greater air flow for evaporative cooling. We examined museum specimens of eastern fox squirrels Sciurus niger, a species native to the United States and one that displays brown, grey or all-black pelage color, and used image analysis procedures to quantify hairs from the dorsal surface and tail. From examination of 43 specimens (19 brown, 9 black and 15 grey), and 1,720 hairs, we found no significant difference in hair lengths across color morphs, but significant differences in hair fiber widths. Black squirrels had thinner body hairs than other forms (7% thinner), but thicker tail hairs (9% thicker) than the others. Given that the dorsal surface would be directly exposed to solar radiation, we interpret this to be an adaptation to prevent heat stress during the day. The thicker tail hairs may be an adaptation for nighttime thermoregulation, since squirrels sleep with their tails wrapped around their bodies. These results add to a growing literature body of the functional significance of mammalian pelage.
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Si, Xiaohong, Mridha Md Zakir, and J. David Dickman. "Afferent Innervation of the Utricular Macula in Pigeons." Journal of Neurophysiology 89, no. 3 (March 1, 2003): 1660–77. http://dx.doi.org/10.1152/jn.00690.2002.
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Biotinylated dextran amine (BDA) was used to retrogradely label afferents innervating the utricular macula in adult pigeons. The pigeon utriclar macula consists of a large rectangular-shaped neuroepithelium with a dorsally curved anterior edge and an extended medioposterior tail. The macula could be demarcated into several regions based on cytoarchitectural differences. The striola occupied 30% of the macula and contained a large density of type I hair cells with fewer type II hair cells. Medial and lateral extrastriola zones were located outside the striola and contained only type II hair cells. A six- to eight-cell-wide band of type II hair cells existed near the center of the striola. The reversal line marked by the morphological polarization of hair cells coursed throughout the epithelium, near the peripheral margin, and through the center of the type II band. Calyx afferents innervated type I hair cells with calyceal terminals that contained between 2 and 15 receptor cells. Calyx afferents were located only in the striola region, exclusive of the type II band, had small total fiber innervation areas and low innervation densities. Dimorph afferents innervated both type I and type II hair cells with calyceal and bouton terminals and were primarily located in the striola region. Dimorph afferents had smaller calyceal terminals with few type I hair cells, extended fiber branches with bouton terminals and larger innervation areas. Bouton afferents innervated only type II hair cells in the extrastriola and type II band regions. Bouton afferents innervating the type II band had smaller terminal fields with fewer bouton terminals and smaller innervation areas than fibers located in the extrastriolar zones. Bouton afferents had the most bouton terminals on the longest fibers, the largest innervation areas with the highest innervation densities of all afferents. Among all afferents, smaller terminal innervation fields were observed in the striola and large fields were located in the extrastriola. The cellular organization and innervation patterns of the utricular maculae in birds appear to represent an organ in adaptive evolution, different from that observed for amphibians or mammals.
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Kanwal, Hummaira, Muhammad Shahzad Aslam, Tayyaba Latif Mughal, Muhammad Asim, and Reena Majid Memon. "Human Hair as Fiber Reinforced Concrete for Enhancement of Tensile Strength of Concrete." January 2020 39, no. 1 (January 1, 2020): 63–70. http://dx.doi.org/10.22581/muet1982.2001.07.
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FRC (Fibre Reinforced Concrete) is fibrous material which increases its structural integrity, resists to explosive spalling in case of environmental affects, improves mix cohesion, improves ductility, reduces of steel reinforcement requirements and reduces the voids due to good stiffness. It contains short discrete fibres that are uniformly distributed. Mostly, natural fibers are the waste material which may have negative impact on environment. Synthetic fibres include steel fibres and glass fibres but natural fibres are coconut fibres and human hair fibres which tends to vary the properties to concrete. In addition, the character of FRC changes with varying concrete, fibre material, geometries, distribution, orientation and densities. Hair fibre concrete gives a practical, cost-effective and convenient method to avoid cracks and deficiencies regarding strength and proper mixing ratio which occurs at a longer period. Fibres have been used to reduce plastic shrinkage and drying shrinkage in concrete. In some structural elements, fibrous concrete can be used to reduce the cost of structure. Different fibres are used to improve the tensile strength of concrete. Human hair are strong in tension. Hair fibres can be utilized as a strengthening material. Hair fibre is a non-decay able matter and available at a cheap rate. Experiments have been performed on fibrous concrete cylinders containing various percentages of human hair which is 0, 0.5, 1 and 1.5% by the weight of cement. A total of seventy-two cylinders have been prepared with FRC having different %ages of hair content. Workability, compressive strength and split tensile strength have been checked at three curing ages i.e. 7, 14 and 28 days. This research will open a new wicket in the horizon of reuse of waste material efficiently in construction industry. This innovation in construction industry will save our natural resources and use fibre in productive and an effective approach.
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Corniani, Giulia, and Hannes P. Saal. "Tactile innervation densities across the whole body." Journal of Neurophysiology 124, no. 4 (October 1, 2020): 1229–40. http://dx.doi.org/10.1152/jn.00313.2020.
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The skin is our largest sensory organ and innervated by afferent fibers carrying tactile information to the spinal cord and onto the brain. The density with which different classes of tactile afferents innervate the skin is not constant but varies considerably across different body regions. However, precise estimates of innervation density are only available for some body parts, such as the hands, and estimates of the total number of tactile afferent fibers are inconsistent and incomplete. Here we reconcile different estimates and provide plausible ranges and best estimates for the number of different tactile fiber types innervating different regions of the skin, using evidence from dorsal root fiber counts, microneurography, histology, and psychophysics. We estimate that the skin across the whole body of young adults is innervated by ∼230,000 tactile afferent fibers (plausible range: 200,000–270,000), with a subsequent decrement of 5–8% every decade due to aging. Fifteen percent of fibers innervate the palmar skin of both hands and 19% the region surrounding the face and lips. Slowly and fast-adapting fibers are split roughly evenly, but this breakdown varies with skin region. Innervation density correlates well with psychophysical spatial acuity across different body regions, and, additionally, on hairy skin, with hair follicle density. Innervation density is also weakly correlated with the size of the cortical somatotopic representation but cannot fully account for the magnification of the hands and the face.
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Beisel, Kirk W., Yesha Wang-Lundberg, Adel Maklad, and Bernd Fritzsch. "Development and evolution of the vestibular sensory apparatus of the mammalian ear." Journal of Vestibular Research 15, no. 5-6 (November 1, 2005): 225–41. http://dx.doi.org/10.3233/ves-2005-155-601.
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Herein, we will review molecular aspects of vestibular ear development and present them in the context of evolutionary changes and hair cell regeneration. Several genes guide the development of anterior and posterior canals. Although some of these genes are also important for horizontal canal development, this canal strongly depends on a single gene, Otx1. Otx1 also governs the segregation of saccule and utricle. Several genes are essential for otoconia and cupula formation, but protein interactions necessary to form and maintain otoconia or a cupula are not yet understood. Nerve fiber guidance to specific vestibular end-organs is predominantly mediated by diffusible neurotrophic factors that work even in the absence of differentiated hair cells. Neurotrophins, in particular Bdnf, are the most crucial attractive factor released by hair cells. If Bdnf is misexpressed, fibers can be redirected away from hair cells. Hair cell differentiation is mediated by Atoh1. However, Atoh1 may not initiate hair cell precursor formation. Resolving the role of Atoh1 in postmitotic hair cell precursors is crucial for future attempts in hair cell regeneration. Additional analyses are needed before gene therapy can help regenerate hair cells, restore otoconia, and reconnect sensory epithelia to the brain.
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Fradette, Julie, Marie-Josée Godbout, Martine Michel, and Lucie Germain. "Localization of Merkel cells at hairless and hairy human skin sites using keratin 18." Biochemistry and Cell Biology 73, no. 9-10 (September 1, 1995): 635–39. http://dx.doi.org/10.1139/o95-070.
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Merkel cells are neurosecretory cells of the skin with epithelial features such as desmosomes and expression of keratins 8, 18, 19, and 20. Merkel cells are scarcely distributed in adult human skin. Although they are present in hair follicles, their density is higher at hairless anatomic sites such as palms and soles. These cells are often innervated by sensory nerve fibers and are thought to be specialized mechanosensory skin receptor cells. However, their precise origin and function are not clearly established. The aim of this study was to localize Merkel cells in human hairless and hairy skin by immunohistochemistry with antibodies Ks18.174 and Ks19.1 directed against keratins 18 and 19, respectively. In glabrous skin of palm and sole, Merkel cells have been localized at the bottom of the rete ridges, in the epidermal basal layer. To study Merkel cell distribution at hairy anatomic sites, we have chosen breast skin, a tissue containing small hair follicles typical of those covering most of the body's surface. Merkel cells were present in the interfollicular epidermis. In hair follicles, they have been identified in the isthmus region.Key words: skin, human, Merkel cell, keratin, hair follicle.
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Zachariah, M. K., G. T. Coleman, D. A. Mahns, H. Q. Zhang, and M. J. Rowe. "Transmission Security for Single, Hair Follicle–Related Tactile Afferent Fibers and Their Target Cuneate Neurons in Cat." Journal of Neurophysiology 86, no. 2 (August 1, 2001): 900–911. http://dx.doi.org/10.1152/jn.2001.86.2.900.
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Transmission from single, identified hair follicle afferent (HFA) nerve fibers to their target neurons of the cuneate nucleus was examined in anesthetized cats by means of paired recording from individual cuneate neurons and from fine, intact fascicles of the lateral branch of the superficial radial nerve in which it is possible to identify and monitor the activity of each group II fiber. Selective activation of individual HFA fibers was achieved by means of focal vibrotactile skin stimulation. Forearm denervation precluded inputs from sources other than the monitored HFA sensory fiber. Transmission characteristics were analyzed for 21 HFA fiber-cuneate neuron pairs in which activity in the single HFA fiber of each pair reliably evoked spike output from the target neuron at a fixed latency. As the cuneate responses to each HFA impulse often consisted of 2 or 3 spikes, in particular at HFA input rates up to ∼20 imp/s, the synaptic linkage displayed potent amplification and high-gain transmission, characteristics that were confirmed quantitatively in measures of transmission security and cuneate spike output measures. In response to vibrotactile stimuli, the tight phase locking in the responses of single HFA fibers was well retained in the cuneate responses for vibration frequencies up to ∼200 Hz. On measures of vector strength, the phase locking declined across the synaptic linkage by no more than ∼10% at frequencies up to 100 Hz. However, limitations on the impulse rates generated in both the HFA fibers their associated cuneate neurons meant that the impulse patterns could not directly signal information about the vibration frequency above 50–100 Hz. Although single HFA fibers are also known to have secure synaptic linkages with spinocervical tract neurons, it is probable that this linkage lacks the capacity of the HFA-cuneate synapse for conveying precise temporal information, in an impulse pattern code, about the frequency parameter of vibrotactile stimuli.
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Fernandez, C., J. M. Goldberg, and R. A. Baird. "The vestibular nerve of the chinchilla. III. Peripheral innervation patterns in the utricular macula." Journal of Neurophysiology 63, no. 4 (April 1, 1990): 767–80. http://dx.doi.org/10.1152/jn.1990.63.4.767.
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1. Nerve fibers supplying the utricular macula of the chinchilla were labeled by extracellular injection of horseradish peroxidase into the vestibular nerve. The peripheral terminations of individual fibers were reconstructed and related to the regions of the end organ they innervated and to the sizes of their parent axons. 2. The macula is divided into medial and lateral parts by the striola, a narrow zone that runs for almost the entire length of the sensory epithelium. The striola can be distinguished from the extrastriolar regions to either side of it by the wider spacing of its hair cells. Calyx endings in the striola have especially thick walls, and, unlike similar endings in the extrastriola, many of them innervate more than one hair cell. The striola occupies 10% of the sensory epithelium; the lateral extrastriola, 50%; and the medial extrastriola, 40%. 3. The utricular nerve penetrates the bony labyrinth anterior to the end organ. Axons reaching the anterior part of the sensory epithelium run directly through the connective tissue stroma. Those supplying more posterior regions first enter a fiber layer located at the bottom of the stroma. Approximately one-third of the axons bifurcate below the epithelium, usually within 5-20 microns of the basement membrane. Bifurcations are more common in fibers destined for the extrastriola than for the striola. 4. Both calyx and bouton endings were labeled. Calyces can be simple or complex. Simple calyces innervate individual hair cells, whereas complex calyces supply 2-4 adjacent hair cells. Complex endings are more heavily concentrated in the striola than in the extrastriola. Simple calyces and boutons are found in all parts of the epithelium. Calyces emerge from the parent axon or one of its thick branches. Boutons, whether en passant or terminal, are located on thin collaterals. 5. Fibers can be classified into calyx, bouton, or dimorphic categories. The first type only has calyx endings; the second, only bouton endings; and the third, both kinds of endings. Calyx units make up 6% of the labeled fibers, bouton units less than 2%, and dimorphic units greater than 92%. The three fiber types differ in the macular zones they supply and in the diameters of their parent axons. Calyx units were restricted to the striola. The few bouton units were found in the extrastriola.(ABSTRACT TRUNCATED AT 400 WORDS)
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Naudin, Gregoire, Philippe Bastien, Sakina Mezzache, Erwann Trehu, Nasrine Bourokba, Brice Marc René Appenzeller, Jeremie Soeur, and Thomas Bornschlögl. "Human pollution exposure correlates with accelerated ultrastructural degradation of hair fibers." Proceedings of the National Academy of Sciences 116, no. 37 (August 26, 2019): 18410–15. http://dx.doi.org/10.1073/pnas.1904082116.
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Exposure to pollution is a known risk factor for human health. While correlative studies between exposure to pollutants such as polycyclic aromatic hydrocarbons (PAHs) and human health exist, and while in vitro studies help to establish a causative connection, in vivo comparisons of exposed and nonexposed human tissue are scarce. Here, we use human hair as a model matrix to study the correlation of PAH pollution with microstructural changes over time. Two hundred four hair samples from 2 Chinese cities with distinct pollution exposure were collected, and chromatographic-mass spectrometry was used to quantify the PAH-exposure profiles of each individual sample. This allowed us to define a group of less contaminated hair samples as well as a more contaminated group. Using transmission electron microscopy (TEM) together with quantitative image analysis and blind scoring of 82 structural parameters, we find that the speed of naturally occurring hair-cortex degradation and cuticle delamination is increased in fibers with increased PAH concentrations. Treating nondamaged hair fibers with ultraviolet (UV) irradiation leads to a more pronounced cortical damage especially around melanosomes of samples with higher PAH concentrations. Our study shows the detrimental effect of physiological concentrations of PAH together with UV irradiation on the hair microstructure but likely can be applied to other human tissues.
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Zerrouk, Abdelkader, Belkacem Lamri, Cumaraswamy Vipulanandan, and Said Kenai. "Performance Evaluation of Human Hair Fiber Reinforcement on Lime or Cement Stabilized Clayey-Sand." Key Engineering Materials 668 (October 2015): 207–17. http://dx.doi.org/10.4028/www.scientific.net/kem.668.207.
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Earthen masonry is generally brittle, weak and susceptible to water ingress damage. Several techniques of earthen masonry stabilization and reinforcement are available for improving their overall engineering properties. However, the inclusion of fiber into soils has a unique advantage. This is because friction between fibers and soil particles increases bonding between the particles. The present study attempts to investigate the resultant strength and ductility behavior when 0.5%, 1% and 2% randomly distributed human hair fibers are used to reinforce both cemented and un-cemented clayey-sand (50% sand and 50% bentonite) soils. The composite soils were tested under laboratory conditions and examined for compaction and unconfined compression strength (UCS) tests. The experimental results show that stress-strain behavior, failure, and strength characteristics of clayey-sand improved with inclusion of fibers. However, the effect of fiber reinforcement is more significant with stabilized clayey sand compared with the control soil mixture. Based on the compressive strength , the cement stabilization had better strength with bentonite clayey sand (50% sand and 50% bentonite) compared to the lime treatment. Addition of cement and lime affected dry density , optimum moisture content, and failure strain of the clayey-sand.
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Furman, Adam C., Sharon G. Kujawa, and M. Charles Liberman. "Noise-induced cochlear neuropathy is selective for fibers with low spontaneous rates." Journal of Neurophysiology 110, no. 3 (August 1, 2013): 577–86. http://dx.doi.org/10.1152/jn.00164.2013.
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Acoustic overexposure can cause a permanent loss of auditory nerve fibers without destroying cochlear sensory cells, despite complete recovery of cochlear thresholds ( Kujawa and Liberman 2009 ), as measured by gross neural potentials such as the auditory brainstem response (ABR). To address this nominal paradox, we recorded responses from single auditory nerve fibers in guinea pigs exposed to this type of neuropathic noise (4- to 8-kHz octave band at 106 dB SPL for 2 h). Two weeks postexposure, ABR thresholds had recovered to normal, while suprathreshold ABR amplitudes were reduced. Both thresholds and amplitudes of distortion-product otoacoustic emissions fully recovered, suggesting recovery of hair cell function. Loss of up to 30% of auditory-nerve synapses on inner hair cells was confirmed by confocal analysis of the cochlear sensory epithelium immunostained for pre- and postsynaptic markers. In single fiber recordings, at 2 wk postexposure, frequency tuning, dynamic range, postonset adaptation, first-spike latency and its variance, and other basic properties of auditory nerve response were all completely normal in the remaining fibers. The only physiological abnormality was a change in population statistics suggesting a selective loss of fibers with low- and medium-spontaneous rates. Selective loss of these high-threshold fibers would explain how ABR thresholds can recover despite such significant noise-induced neuropathy. A selective loss of high-threshold fibers may contribute to the problems of hearing in noisy environments that characterize the aging auditory system.
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Rudy, L., R. Sneath, and M. Song. "High-voltage Electron Microscopy and 3-D reconstruction of human hair fiber ultrastructure." Proceedings, annual meeting, Electron Microscopy Society of America 47 (August 6, 1989): 116–17. http://dx.doi.org/10.1017/s0424820100152550.
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The basic morphology of the non-keratinous regions of human hair fibers was studied using both conventional and high voltage electron microscopy. The non-keratinous regions of hair include the endocuticle, the cell membrane complex, and the nuclear remnants of the cortex. By characterizing these regions more clearly, the mechanisms by which external influences affect the hair can be understood. The nuclear remnants are surrounded by a cell membrane complex. Since thin sectioning often causes artifacts in these fragile structures, a three-dimensional reconstruction using serial, semi-thick sections was completed to reveal their morphological nature.Human hair fibers collected from a female subject, had not been treated with any chemically active processes. One centimeter samples were collected near the scalp region of the back of the head. The fibers were embedded in Epon-812. Serial, semi-thick sections, 0.25u thick, were sectioned and collected on copper slot, formvar-coated grids. Post-staining was completed with uranyl acetate and lead citrate. Sections were examined in an AEl EM7 Mk 1.2MV HVEM at an accelerating voltage of 1.0 MV.
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Fernández-Peña, Laura, and Eduardo Guzmán. "Physicochemical Aspects of the Performance of Hair-Conditioning Formulations." Cosmetics 7, no. 2 (April 10, 2020): 26. http://dx.doi.org/10.3390/cosmetics7020026.
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Most of the currently used products for repairing and conditioning hair rely on the deposition of complex formulations, based on mixtures involving macromolecules and surfactants, onto the surface of hair fibers. This leads to the partial covering of the damaged areas appearing in the outermost region of capillary fibers, which enables the decrease of the friction between fibers, improving their manageability and hydration. The optimization of shampoo and conditioner formulations necessitates a careful examination of the different physicochemical parameters related to the conditioning mechanism, e.g., the thickness of the deposits, its water content, topography or frictional properties. This review discusses different physicochemical aspects which impact the understanding of the most fundamental bases of the conditioning process.
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Ezawa, Yusuke, Shinobu Nagase, Akira Mamada, Shigeto Inoue, Kenzo Koike, and Takashi Itou. "Stiffness of Human Hair Correlates with the Fractions of Cortical Cell Types." Cosmetics 6, no. 2 (April 1, 2019): 24. http://dx.doi.org/10.3390/cosmetics6020024.
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(1) Background: The objective of this work was to elucidate the hair microstructure which correlates with the stiffness of human hair fibers. (2) Methods: Bending moduli of hair fibers were evaluated for the hair samples from 156 Japanese female subjects. Hair transverse sections were dual-stained with fluorescent dyes which can stain para- and ortho-like cortical cells separately, and observed under a fluorescence light microscope. Atomic force microscopy nanoindentation measurements were performed to examine the modulus inside macrofibrils. (3) Results: The difference in bending moduli between the maximum and the minimum values was more than double. The hair of high bending modulus was rich in para-like cortical cells and the bending modulus significantly correlated with the fraction of para-like cortical cells to the whole cortex. On the other hand, the elastic moduli inside macrofibrils were almost same for the para- and ortho-like cortical cells. (4) Conclusions: Hair bending modulus depends on the fractions of the constitutional cortical cell types. The contribution of the intermacrofibrillar materials, which differed in their morphologies and amounts of para- and ortho-like cortical cells, is plausible as a cause of the difference in the modulus of the cortical cell types.
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Ribaudo, Anthony J. "Quantifying Polymer Deposition on Hair Fibers by Microfluorometry." Microscopy Today 27, no. 4 (July 2019): 24–30. http://dx.doi.org/10.1017/s155192951900066x.
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Keis, K., K. R. Ramaprasad, and Y. K. Kamath. "Studies of light scattering from ethnic hair fibers." International Journal of Cosmetic Science 26, no. 4 (August 2004): 218. http://dx.doi.org/10.1111/j.0142-5463.2004.00223_4.x.
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Das, Trina, and Gita N. Ramaswamy. "Enzyme Treatment of Wool and Specialty Hair Fibers." Textile Research Journal 76, no. 2 (February 2006): 126–33. http://dx.doi.org/10.1177/0040517506063387.
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Mizuno, Hiroyasu, Gustavo S. Luengo, and Mark W. Rutland. "Interactions between Crossed Hair Fibers at the Nanoscale." Langmuir 26, no. 24 (December 21, 2010): 18909–15. http://dx.doi.org/10.1021/la103001s.
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Morgello, Susan, Hart de C. Peterson, Leonard J. Kahn, and Hilda Laufer. "Menkes Kinky Hair Disease with ‘Ragged Red’ Fibers." Developmental Medicine & Child Neurology 30, no. 6 (November 12, 2008): 812–16. http://dx.doi.org/10.1111/j.1469-8749.1988.tb14644.x.
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Yu, Yang, Wen Yang, and Marc André Meyers. "Viscoelastic properties of α-keratin fibers in hair." Acta Biomaterialia 64 (December 2017): 15–28. http://dx.doi.org/10.1016/j.actbio.2017.09.012.
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