Yes / Background: Multiple biomarkers have been associated with hair loss in women, but studies showed inconsistent results. Objective: We investigated the association between markers of cardiovascular disease risk (e.g., serum lipid levels and hypertension) and aging (e.g., 25-hydroxyvitamin D and insulin-like growth factor) with hair loss in a population of middle-aged women. Methods: In a random subgroup of 323 middle-aged women (mean age: 61.5 years) from the Leiden Longevity Study, hair loss was graded by three assessors using the Sinclair scale; women with a mean score higher than 1.5 were classified as cases with hair loss. Results: Every standard deviation increase in HDL cholesterol was associated with a 0.65 times lower risk (95% confidence interval [CI]: 0.46–0.91) of hair loss; for IGF-1 the risk was 0.68 times lower (95% CI: 0.48–0.97) per standard deviation increase, independent of the other studied variables. Women with both IGF-1 and HDL cholesterol levels below the median of the study population had a 3.47 times higher risk (95% CI: 1.30–9.25) of having hair loss. Limitations: The observational setting limits causal inference of the findings. Conclusion: Low HDL cholesterol and IGF-1 were associated with a higher risk of hair loss in women. / This study was funded by the Innovation Oriented Research Program on Genomics (SenterNovem; IGE01014 and IGE5007), the Centre for Medical Systems Biology (CMSB), the Netherlands Genomics Initiative/Netherlands Organization for Scientific Research (05040202 and 050-060-810, NCHA), Unilever PLC and the European Union-funded Network of Excellence Lifespan (FP6 036894).

No

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No description available.

Yes

Vestibular hair cells are mechanotransducing sensory receptors in the vertebrate inner ear that detect movement and orientation of the head with respect to gravity. The morphologies of their ciliary bundles vary greatly for different species, endorgans, and within the same endorgan. Bundle morphology in the turtle utricle, like other species, demonstrates highly organized regional variations. These structural differences in bundles impact their mechanical behavior and the process of mechanotransduction. To further understanding of the mechanical behavior of hair bundles, this work experimentally measured the stiffness of bundles with differing morphology, the stiffness contribution of interciliary links and the mechanical properties of the kinocilium in the turtle utricle. The stiffness of hair bundles of varying structure and location along a medial to lateral transect of the utricle was examined. Bundle stiffness was greatest in the striola and demonstrated a systematic decline with location from the line of polarity reversal. The average stiffness of bundles in the striola and extrastriola were 82 ± 46 (n=48) and 9 ± 5 (n=25) µN/m, respectively. The stiff and weak bundles demonstrated characteristic morphologies. The stiffest bundles have short kinocilium, tall stereocilia, and ratios of kinocilium to tallest stereocilia height (KS) close to 1. In contrast, the compliant bundles have tall kinocilium, short stereocilia, and KS ratios ranging from 1.6 – 8. The stiffer bundles also tend to have longer array lengths and steeper slopes. Measurements of bundle stiffness in the turtle utricle are lower than those previously reported which may be attributed to morphological differences between species. The stiffness contributions of the interciliary links were also examined through their selective removal with exposure to the Ca²⁺ chelator BAPTA and the protease subtilisin. BAPTA treatment reportedly breaks tip, kinocilial and ankle links while subtilisin breaks the shaft and ankle links. Following BAPTA and subtilisin treatments, bundle stiffness reduced by 65 ± 10% and 63 ± 11%, respectively. The mechanical properties of the kinocilium were measured with novel techniques. Flexural rigidity (EI) was measure while the kinocilium was fixed at the height of the tallest stereocilia using a glass supporting probe. Through both force deflection and a high speed video technique, measured values of EI ranged from 1460 – 6150 pN·µm2. The rotational stiffness of the kinocilium about its apical insertion was also measured. Bundles were treated with BAPTA to break the kinocilial links and separate the kinocilium from neighboring stereocilia. Using a force deflection technique, the rotational stiffness of the kinocilium was measured as 120 ± 17 pN·µm/rad. / Ph. D.

<p>Creating three dimensional hair is still one of the hardest elements when creating characters. Problems occur because of the constant changes in the software every few years. A major goal is to create as realistic hair as possible in Autodesk Maya and to supply this detailed information on to other 3D artist. Techniques are researched and reviewed on how different hair systems are created, as well as how dynamic effects react on the moving hair.</p>

Creating three dimensional hair is still one of the hardest elements when creating characters. Problems occur because of the constant changes in the software every few years. A major goal is to create as realistic hair as possible in Autodesk Maya and to supply this detailed information on to other 3D artist. Techniques are researched and reviewed on how different hair systems are created, as well as how dynamic effects react on the moving hair.

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