The surface and structural change of human hair fibre have been analysed to determine the oxidation effects for bleached hairs. Three types of bleached hairs (6% H2O2 bleach, 9% H2O2 commercial bleach and commercial persulphate bleach (contains 9% H2O2)) as well as virgin hair were evaluated with the increasing treatment time using Scanning Electron Microscopy (SEM), Reflective Spectrophotometry, Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared (FTIR) Spectroscopy. It is obvious that longer treatment times result in the greater surface and structural damage. However, commercial persulphate bleach causes less surface damage for the cuticle. 6% H202 bleach has overall moderate damage effects on both cuticle and cortex over the treatment time. 9% H2O2 commercial bleach indicates two different damage stages. The first 1.5h bleached hairs show mild oxidation to the surface, whereas the damage becomes heavy after 2h. This phenomenon results in that 9% H2O2 commercial bleach has a more intensive oxidation damage in the cortex than the commercial persulphate bleach. This is in line with DSC investigation which shows that the intermediate filament of 9% H2O2 commercial bleach is heavily damaged after the extensive oxidation time (greater than or equal to2h). Although commercial persulphate bleach contains the stronger oxidising agent, it has a less surface damage than 9% H2O2 commercial bleached hair in FTIR-ATR measurement, and a similar oxidation effect on the matrix as 6% H202 bleached hair in FTIR transmission investigation. In addition, it has been verified by colour measurements that bleached hairs have an overall lighter, yellowish and reddish colour. Consequently, commercial persulphate bleached hair is much lighter and more yellow than 9% H2O2 commercial bleached hair and 6% H202 bleached hair. DSC investigations reveal that the three bleaches have a homogenous oxidation effect on IFs and IFAPs. The deconvolution results using three Gaussian distributions confirm this observation. The stronger bleach results in a homogenous structural damage on both para- and ortho-cortex with increasing bleaching time. Commercial persulphate bleach and 9% H2O2 commercial bleach have a progressive damage effect on the ortho- and para- cortex than 6% H202 bleach. Kinetics analysis is conducted for the virgin and bleached hairs by using various heating rates according to ASTM-E698. The activation energies of 260 kJ/mol for the virgin hair and 295 kJ/mol for the commercial persulphate bleached hair (2h) are determined from the slope of the regression line of peak temperature, TD (as 1/TD) and heating rate, β (as lnβ) on the basis of the Arrhenius-equation. The predominant structural damage for various heating rates only occurs in the IF. It is shown that a linear increase in DeltaHD occurs for lower heating rates, while it is constant for higher heating rates. This can be ascribed to the hypothesis that a lower heating rate favours a crystal transformation change (alpha-β transformation), while a higher rate favours a crystalline-amorphous transformation. SEM examines the morphological changes of hair samples after DSC. The cortex has been dissolved at the lower heating rate. The commercial persulphate bleached hairs (2h) show an overall shrunk cuticle surface and fewer and smaller hydrolysed protein granules, due to the previous damage of the alpha-helix in the cortical cell.

Orientador: Ines Joekes / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-13T13:29:11Z (GMT). No. of bitstreams: 1 Nogueira_AnaCarolinaSantos_D.pdf: 2247460 bytes, checksum: aeee4e416431ea072521f3f9a542b8ca (MD5) Previous issue date: 2008 / Resumo: A exposição solar causa diversos danos ao cabelo, sendo a mudança na cor um dos mais perceptíveis. Apesar do interesse em soluções para proteção da cor do cabelo, questiona-se ainda na literatura a sensibilidade de diferentes cabelos à foto-oxidação, danos causados pelas faixas de comprimentos de onda e o desempenho da melanina como uma proteção natural à fibra. Neste trabalho cabelos branco, preto, castanho-escuro, loiro e ruivo, melanina Sepia officinalis (eumelanina), bem como os aminoácidos tirosina e triptofano, foram expostos às radiações de lâmpada de vapor de mercúrio (filtrando-se ou não a radiação UVB) por até 2600 h, de arco-xenônio por até 300 h e à radiação IV por até 600 h. Na lâmpada de vapor de mercúrio, a exposição ocorreu a T=30°C e 50% de UR e na lâmpada de arco-xenônio a T=50°C e 50% de UR. Através de medidas de espectrofotometria de reflectância difusa, obtiveram-se, na ausência de radiação UVB, valores do parâmetro DE*= 20,0 e DE*=10,0 para os cabelos loiro e branco, respectivamente. Para a mesma dose de radiação (630 MJ/m), foram obtidos valores em torno de 3,0 para os cabelos castanho-escuro e preto. Contrariamente ao que é relatado na literatura, o cabelo branco ficou significativamente menos amarelo (Db*= -8,0) após ambas as condições de exposição na lâmpada de vapor de mercúrio. O cabelo loiro ficou menos amarelo (Db*=-3,0) na ausência da radiação UVB e mais amarelo (Db*=2,0) com radiação UVB. Os cabelos castanho escuro e preto ficaram mais vermelhos (Da*=2,0) e mais amarelos (Db*=3,0) após qualquer condição de exposição. O cabelo ruivo foi exposto a uma dose de radiação acumulada de até 150 MJ/m, sendo obtidos, na ausência de radiação UVB, valores de DE*= 5,0. O mesmo ficou mais amarelo (Db*=3,0) e não foi observada tendência de mudança no parâmetro Da*, após qualquer condição de exposição. Observou-se que o amarelecimento do cabelo branco é causado pela radiação IV (Db*=2,0). Esta mesma radiação não alterou a cor dos cabelos pigmentados. Os valores de absorbância de soluções de melanina, obtidos por espectroscopia no UV-VIS, mudaram significativamente após foto-exposição e foi possível correlacioná-los com a mudança de cor ocorrida no cabelo. Não foi possível, entretanto, obter uma correlação da alteração no triptofano com o amarelecimento do cabelo branco. Nos ensaios de resistência mecânica se observou, após foto-exposição (radiação UVB inclusa), redução na força máxima de 50%, 25%, 25% e 29% e redução no alongamento máximo de 20%, 15%, 14% e 9% para os cabelos branco, loiro, castanho-escuro e preto, respectivamente. Através dos resultados obtidos, correlacionou-se a mudança de cor com alterações em diferentes estruturas do cabelo, concluindo-se que a luminosidade, o amarelecimento e o avermelhamento estão relacionados primeiramente com a quantidade de melanina degradada, alterações nas proteínas e na melanina, respectivamente. Os ensaios de resistência mecânica mostraram que a ausência de melanina causa reduções bastante significativas na resistência do fio. Entretanto, a presença de uma quantidade muito maior de melanina no cabelo não o torna significativamente mais resistente à quebra / Abstract: Solar exposure causes hair damages. Changes on hair color are particularly noticeable. Although it is of general interest to find solutions for hair color protection, questions as the sensibility of different hair types to photo-oxidation, damages caused by the different wavelengths, and the efficacy of melanin as a natural hair color protector, are still open today. In this work, white, black, dark-brown, blond and red hairs, Sepia officinalis melanin, as well as the amino acids tyrosine and tryptophan were exposed to the radiations of a mercury vapor lamp (filtering or not UVB radiation) for up to 2600 h, of an arc-xenon lamp for up to 300 h and to IV radiation for up to 600 h. The temperature and relative humidity measured were T=30°C and 50% RH and T=50°C and 50% RH, for the mercury and xenon lamps, respectively. Using diffuse reflectance spectrophotometry, DE* values of 20.0 and 10.0 were obtained for blond and white hair, respectively, both hair irradiated in the absence of UVB radiation (accumulated irradiation dose = 630 MJ/m). Under the same conditions values of DE* around 3.0 for the black and dark-brown hairs were obtained. Opposite to what is commonly found in literature, the white hair turned significantly less yellow (Db*= -8.0) after exposure to the mercury vapor lamp. The blond hair turned less yellow (Db*= -3.0) in the absence of UVB radiation and yellowier (Db*= 2.0) when this radiation was included on the system. The dark-brown and black hairs turned redder (Da*= 2.0) and yellowier (Db*=3.0) after any exposure condition. The red hair was exposed to an irradiation dose up to 150 MJ/m. In the absent of UVB radiation, values of DE* around 5.0 were obtained. This hair turned yellowier (Db*=3.0) and no significant changes were observed on the Da* parameter, after any exposure condition. It was observed that the yellowness of white hair is caused by IV radiation (Db*= 2.0). This radiation did not alter the color of the pigmented hairs. The absorbance values of melanin solutions, obtained by UV-VIS spectroscopy, changed significantly after photo-oxidation and it was possible to correlate with the hair color changes. On the other hand, it was not possible to correlate changes in tryptophan solutions with the yellowness of white hair. The mechanical resistance experiments, after photo-oxidation with UVB radiation included, showed a reduction on break strength of 50%, 25%, 25% and 29% and a reduction on breaking elongation of 20%, 15%, 14% and 9% for white, blond, dark-brown and black hairs, respectively. From the results obtained it is possible to correlate hair color changes with the different hair pigmentation, concluding that the luminosity, the yellowness and the redness are linked mainly with the amount of melanin degraded, proteins and melanin damages, respectively. The results of mechanical resistance showed that the absence of melanin on hair causes significant decrease on the fiber resistance. On the other hand, a greater amount of melanin on hair content (e.g., dark-brown x blond hair) does not produce significant differences on its mechanical resistance / Doutorado / Físico-Química / Doutor em Ciências

The hair cycle represents a dynamic process during which a complex mini- organ, the hair follicle, rhythmically regresses and regenerates. The control mechanism that governs the hair cycle ('hair cycle clock') is thought to be an autonomous oscillator system, however, its exact nature is not known. This thesis aims to understand the human hair cycle as a systems biology problem using theoretical and experimental techniques in three distinct study approaches. Using mathematical modelling, a simple two-compartment model of the human hair cycle was developed. The model concentrates on the growth control of matrix keratinocytes, a key cell population responsible for hair growth, and bi-directional communication between these cells and the inductive fibroblasts of the dermal papilla. A bistable switch and feedback inhibition produces key characteristics of human hair cycle dynamics. This study represents the first mathematically formulated theory of the 'hair cycle clock'.A second chronobiological approach was adopted to explore the molecular control of the human hair follicle by a peripheral clock mechanism. The hypothesis was tested that selected circadian clock genes regulate the human hair cycle, namely the clinically crucial follicle transformation from organ growth (anagen) to organ regression (catagen). This revealed that intra- follicular expression of core clock and clock-controlled genes display a circadian rhythm and is hair cycle-dependent. Knock-down of Period1 and Clock promotes anagen maintenance, hair matrix keratinocyte proliferation and stimulates hair follicle pigmentation. This provides the first evidence that peripheral Period1 and Clock gene activity is a component of the human 'hair cycle clock' mechanism. Lastly, an unbiased gene expression profiling approach was adopted to establish important genes and signalling pathways that regulate the human hair cycle. This revealed that similar genes and pathways previously shown to control the murine hair cycle in vivo, such as Sgk3, Msx2 and the BMP pathway, are also differentially regulated during the anagen-catagen transformation of human hair follicles. In summary, by using a three-pronged systems biology approach, the thesis has shed new light on the control of human hair follicle cycling and has generated clinically relevant information: a) The hair cycle model may predict how hair cycle modulatory agents alter human hair growth. b) Period1 and Clock are new therapeutic targets for human hair growth manipulation. c) Gene expression profiling points to additional key players in human hair cycle control with potential for future therapeutic targets.

Orientador: Ines Joekes / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-07T21:43:58Z (GMT). No. of bitstreams: 1 Wagner_RitadeCassiaComis_D.pdf: 5300466 bytes, checksum: b220b80949a0b5e00e05ecef6360d5ac (MD5) Previous issue date: 2006 / Resumo: O cabelo é uma estrutura protéica de queratina formada por quatro estruturas principais: as cutículas, o córtex, o cimento intercelular (CMC) e a medula. Esta última nem sempre está presente no fio e, por acreditar-se que sua influência nas propriedades da fibra é negligenciável, foi pouco estudada. Este trabalho almeja esclarecer as estruturas da medula e verificar sistematicamente se ela afeta alguma propriedade na fibra. Os fios medulados e sem medula provenientes do mesmo couro cabeludo foram identificados e separados em mechas utilizando um micro-estereoscópio. Encontraram-se dois tipos de medula (fina e grossa) que foram diferenciadas por microscopia eletrônica de varredura (MEV) e de transmissão (MET). A medula tem uma estrutura esponjosa composta por três unidades principais: a fibrilar (desalinhada com as fibrilas do córtex), os glóbulos e uma camada de CMC na interface com o córtex. Por MET constatou-se que a medula fina é morfologicamente diferente da medula grossa. A medula fina apresenta contraste, interface limitada pelo CMC, nenhum grânulo de melanina e menor diâmetro. A medula grossa apresenta mais glóbulos, bem como maiores dimensões das cavidades, alguns grânulos de melanina disformes e organização gradual das células de fora para dentro. Essas características morfológicas sugerem que a medula seria um córtex em estágio atrasado de formação. Utilizando-se um espectrofotômetro de refletância difusa (ERD), verificou-se que os fios com medula são mais escuros, menos vermelhos e menos amarelos que os fios sem medula oriundos do mesmo couro cabeludo. Sugere-se que as cavidades da medula causem o espalhamento e o confinamento de luz pela diferença de índice de refração com o córtex, diminuindo, então, a reflexão externa da fibra, já que praticamente não possui melanina. Para a mecha estudada, a diferença de cor total está em 4,7 unidades de cor e é visível a olho nu. A medula, então, deve ser considerada em estudos de cor, juntamente com as melaninas e as condições de preservação das cutículas. Já nas propriedades mecânicas, a medula causa uma maior heterogeneidade nas curvas de tensão-deformação, mas não muda os valores médios das propriedades estudadas. Os fios medulados são mais espessos que fios sem medula. Descontando-se o valor do diâmetro da medula do diâmetro total da fibra, têm-se valores aproximados aos dos fios sem medula. A heterogeneidade observada é proveniente da diferença percentual que o diâmetro da medula representa do diâmetro total da fibra. Observaram-se mudanças estruturais quando o cabelo com medula fina é submetido à imersão em SDS 10 % e à 75 °C, transformando-se em medula grossa após os tratamentos / Abstract: Human hair is a keratinous material divided into four main units: cuticles, cortex, intercellular cement (CMC) and medulla. The last one could be present or not in the shafts. There are few studies about it mainly because it is believed to have small or no influence on any hair property. The present work aims to clarify the medulla structure and to systematically verify if mechanical or color properties are affected by its presence in the fiber. Medullated and unmedullated fibers from the same scalp were identified by stereo-microscopy and separated into tresses. Two kinds of medulla were found: thin and thick medulla. Their morphology was characterized by scanning (SEM) and transmission (TEM) electron microscopy. Medulla has a sponge structure composed by three units: fibril (not aligned longitudinally as in the cortex), globular and CMC layer in the interface with the cortex. Thin and thick medullas are different in TEM. Thin medulla has contrast, CMC limited interface, no melanin and smaller diameter. Thick medulla has more globular structures, larger cavities, some elliptical melanin granules and a gradual organization from the outside to the inner side of the medulla. These data suggest that medulla is in an earlier stage of the differentiation process compared to the cortex. Color data obtained using a diffuse reflectance spectrophotometer showed that unmedullated fibers are clearer, redder and yellowier than medullated fibers. Once that medulla presents no melanin, we suggest that the medulla cavities cause scattering and confinement of light by the difference with the refractive index of cortex which decreases the external reflectance of the fiber. For the studied tress, the total color difference was 4.7 (visible to naked eyes). Thus, medulla together with melanin and cuticles must now be considered in studies of hair color. Average values of the mechanical properties are similar for unmedullated and medullated fibers. However, higher dispersion in data for medullated fibers is observed. Unmedulated fibers are more uniform and show smaller diameters. These data indicate that the air cavities in medulla could act as defects but do not interfere in the crystalline character of the fiber. Thus, the heterogeneity observed might be attributed to the difference between the medulla diameter with the whole fiber diameter. Thin medulla regions became thick medulla after immersion in SDS 10 % and after 24 h at 75 °C / Doutorado / Físico-Química / Doutor em Ciências

The project Kera-Plast aims to re-loop humans and nature by questioning the current systems and ethics through materiality. Human hair, currently considered as waste, functions as the base for the material exploration fabricated through thermo-compression molding. The flexible, short and opaque keratin-fibers get glued together with heat, pressure and water, acting as a plasticizer during the compression molding process. The results are stiff and remind on plastic due to shine and translucency. Aesthetics and function of the resulting material are controlled and designed by traditional textile techniques as knitting, weaving and non-woven processes. The material samples display the potential of Kera-Plast in the categories of 3D surface structures, patterns, shapeability and the influence of light. The findings also provide information about the parameters for designing with keratin fibers through the thermo-compression process. It can be concluded that despite all ethical and cultural factors, Kera-Plast and its fabrication method has the potential to add a sustainable, functional and aesthetical value to the design field and our future material consumption.

no / Pomiferin is a unique, prenylated isoflavonoid that can be isolated and purified from the fruits of Maclura pomifera (Osage Orange). The molecule typically is isolated with a small amount of a molecule called Osajin which is structurally similar to Pomiferin but lacks an aromatic hydroxyl group. As a consequence, Osajin has been shown to be a less effective antioxidant than Pomiferin. In vitro studies on Normal Human Dermal Fibroblasts demonstrate that Pomiferin is a potent extracellular matrix protein stimulant, showing increases in collagen, elastin and fibrillin expression comparable or superior to equivalent concentrations of retinol. Ex vivo hair follicle assays demonstrate comparable effects on expression of collagen and elastin at Pomiferin concentrations in the range of 0.05–5 ppm. Taken together, the results from the two assays conducted on different models indicate that Pomiferin may be a very interesting ingredient for topical skin and scalp treatments where modulation of the expression of extracellular matrix proteins is important.

no / The development of hair follicle organ culture techniques is a significant milestone in cutaneous biology research. The hair follicle, or more accurately the "pilo-sebaceous unit", encapsulates all the important physiologic processes found in the human body; controlled cell growth/death, interactions between cells of different histologic type, cell differentiation and migration, and hormone responsitivity to name a few. Thus, the value of the hair follicle as a model for biological scientific research goes way beyond its scope for cutaneous biology or dermatology alone. Indeed, the recent and dramatic upturn in interest in hair follicle biology has focused principally on the pursuit of two of biology's holy grails; post-embryonic morphogenesis and control of cyclical tissue activity. The hair follicle organ culture model, pioneered by Philpott and colleagues, ushered in an exceptionally accessible way to assess how cells of epithelial (e.g., keratinocytes), mesenchymal (e.g., fibroblasts), and neuroectodermal (e.g., melanocytes) origin interact in a three-dimensional manner. Moreover, this assay system allows us to assess how various natural and pharmacologic agents affect complex tissues for growth modulation. In this article, I focus on the culture of the human hair follicle mini-organ, discussing both the practical issues involved and some possible research applications of this assay.

Lack of hair due to alopecia or skin grafting procedures causes significant distress due to hair's role in social and sexual communication. Only limited pharmacological agents are currently available to stimulate hair growth; their development is hampered by inappropriate model systems. Most research involves large terminal scalp follicles rather than the clinical targets of tiny vellus or intermediate follicles. The overall aim of this thesis was to develop a novel model system based on intermediate hair follicles. Initially, intermediate follicles from female pre-auricular skin were characterised and compared to matched terminal follicles. Intermediate follicles were smaller, less pigmented, shorter and possessed a more 'tubular' bulb morphology than their more 'bulbous' terminal counterparts. Significant correlations were demonstrated between various hair follicle measurements and corresponding dermal papilla diameters. Isolated terminal follicles grew significantly more than intermediate hair follicles in organ culture for 9 days. Testosterone (10nM), the major regulator of human hair growth, increased only intermediate follicle growth; the anti-androgen, cyproterone acetate (1¿M), prevented this stimulation, unlike the 5¿-reductase type 2 inhibitor finasteride (40ng/ml). Immunohistochemistry demonstrated androgen receptor and 5¿-reductase type 2 proteins in both follicle types, while quantitative real-time PCR and gene microarray analysis detected their increased gene expression in intermediate follicles. Thus, smaller intermediate follicles showed major morphological and gene expression differences to terminal follicles in vivo and retained significant, biologically-relevant differences in vitro in organ culture including androgen-responsiveness. Therefore, intermediate hair follicles offer a novel, exciting, more clinically relevant, albeit technically difficult, model for future investigations into hair growth.

No description available.

<p>Carbon and nitrogen isotope values in sequential segments of human hair keratin provide an archive of temporal fluctuations in isotopic composition close to the time of an individual’s death. By combining stable isotope analysis with a microscopic examination of hair, this thesis explores health status prior to the death of early settlers from St. Thomas’ Anglican Church cemetery in Belleville, Ontario (1821-1874). The purpose of this thesis is to determine if there is a consistent difference in carbon and nitrogen isotopic signatures along sequentially segmented hair in individuals who have observable pathological conditions versus individuals who display no osteological evidence of pathology. Elevated nitrogen values can be associated with physiological stressors such as chronic illness, infection, or injury that affect an individual’s metabolic state. Elevated nitrogen values represent a recycling of nitrogen derived from the breakdown of existing proteins in the body and subsequent tissue repair. Results from 10 individuals indicate that δ¹⁵N values increase greater than 1‰ if an individual was suffering from a pathological condition (e.g., periostitis) or decrease by 1‰ if an individual was possibly pregnant, while δ¹³C values remained relatively constant. The variability in nitrogen values over 1‰, coinciding with less change in δ¹³C values, may be indicative of physiological stress. These results suggest that δ¹⁵N values are not only useful for studying diet, but may also be used as indicators of physiological stress.</p> / Master of Arts (MA)