Esta dissertação apresenta a caracterização físico-química e termoanalítica de amostras de cabelo humano. Estudos comparativos entre amostras de queratina comercial e de cabelo caucasiano, oriental, tratados, naturais foram realizados para um melhor entendimento de suas características e comportamento. Para a caracterização das amostras foram utilizadas técnicas como AE, espectroscopia de absorção no infravermelho, difratometria dos raios X, MEV, AFM e análise térmica. Os resultados de análise elementar e espectroscopia no infravermelho não permitem diferenciar as amostras quanto à etnia, sexo, idade ou coloração da fibra. A pulverização das amostras facilita a realização dos ensaios de caracterização, porém amostras na forma de fio são mais adequadas para os estudos de DSC. As imagens de MEV e AFM evidenciaram grandes variações na estrutura superficial de amostras de cabelo natural e submetidas a tratamentos de beleza. Os resultados de análise térmica forneceram informações quanto ao comportamento térmico do cabelo, em relação à desidratação, região da transição vítrea e as etapas de decomposição térmica das amostras na forma fio e pó. O cabelo possui elevada concentração de queratina, como descrito na literatura, independente da matriz, e quando submetido a processos de modelagem, que envolvam elevada temperatura (secadores, piastra/prancha e baby liss) pode sofrer danos irreversíveis à estrutura da fibra capilar. / This dissertation presents the physico-chemical and thermoanalytical characterization of human hair samples. Comparative studies of samples of commercial keratin and caucasian, oriental, treated, natural hair were conducted to better understand their characteristics and behavior. For the sample characterization were used elemental analysis, infrared spectroscopy, X-ray diffraction, SEM, AFM and thermal analysis techniques. The results of elemental analysis and infrared spectroscopy did not vary between samples with respect to ethnicity, age, color fiber and belonged to individuals male or female. Samples in powder form facilitate the testing of characterization, but in the form of wire samples are more suitable for DSC studies. The SEM and AFM images showed large variations in the surface structure of samples subjected to natural hair and beauty treatments. The thermal analysis results provide information about the thermal behavior of hair, compared to dehydration, glass transition region and thermal decomposition steps of samples in wire and powder form. The hair has a high concentration of keratin, as described in the literature, regardless of the array. And, when subjected to modeling processes involving high temperature and (dryers, piastre / board and baby liss) can cause irreversible damage to the structure of the hair fiber.

Our lab recently described a role for JAK-STAT signaling in the maintenance of quiescence during the murine hair cycle. Research into signaling pathways and cytokines/growth factors involved in the mammalian hair cycle has not focused extensively on the JAK-STAT pathway. In this thesis, I investigated the upstream effector(s) and downstream mechanisms of JAK-STAT signaling in the HFSC during telogen, using a variety of methods, including murine conditional mutants of the JAK-STAT pathway, pharmacological and immunological techniques. The mechanism through which OSM exerts this effect is via JAK-STAT5 signaling downstream of the OSM receptor, which is antagonized by pharmacological JAK inhibition. Conditional epidermal ablation of OSMR or STAT5 during early- and mid-telogen (P42 – P60) shortens the telogen phase significantly, and inhibition of macrophages by way of neutralizing antibodies, small molecule inhibitors, and genetic ablation (with Csf1r-CreER::R26-iDTR mice) during telogen also promotes hair growth. Single-cell RNA sequencing of dermal immune cells across murine telogen identified a distinct subset of TREM2+ macrophages that are enriched for OSM, and gene-set analysis suggests these “trichophages” are similar to the microglia of the central nervous system. I show that this distinct subset of TREM2+ macrophages predominate during early- and mid-telogen, where they produce Oncostatin M (OSM), which is sufficient to maintain quiescence of hair follicle stem cells (HFSCs). Proliferation of HFSCs and hair growth is associated with depletion of this subset of TREM2+ macrophages. Interestingly, macrophage markers and OSM were found to be upregulated in the balding scalp of males with androgenetic alopecia, suggesting that this mechanism is physiologically relevant in the control of human hair cycling.

Orientador: Nivar Gobbi / Banca: Katia Cury Roselli / Banca: Eliana Ferraz Santos / Banca: Ricardo Tadeu Santori / Banca: Sônia Aparecida Talamoni / Resumo: O estudo das características microscópicas dos pêlos de mamíferos tem sido desenvolvido com o propósito de utilizá-las como critério taxonômico, especialmente para a identificação de restos presentes em fezes, conteúdos estomacais e bolotas de regurgitação de predadores. Os pêlos são menos danificados no processo digestivo, e são freqüentemente a única prova para identificação da presa em estudos de hábito alimentar, já que ossos e dentes sofrem intensa fragmentação durante a mastigação apresentando baixo valor diagnóstico, portanto um conhecimento maior da estrutura do pêlo facilita esses estudos e oferece uma base para estudos mais completos de predação e seus efeitos sobre as espécies de presa. Assim, os objetivos do presente projeto foram o desenvolvimento de técnicas de preparação de lâminas de pêlos para coleções e observações diretas; o desenvolvimento de uma chave de identificação de alguns roedores de mata atlântica baseada em pêlos; e a análise morfométrica dos pêlos de algumas espécies de roedores para a comparação com dados biométricos. Foram desenvolvidas 3 novas técnicas para a preparação de lâminas para a observação da medula de pêlos e outras 3 para a observação do padrão cuticular. Essas técnicas proporcionam um maior índice de sucesso na preparação de lâminas, aumentando também a visibilidade dos padrões e consequentemente as possibilidades de pesquisas na área. / Abstract: The mammal hair identification has been used across the world for studies in forensics, in the field of public health, in textile fibers research, and in mammals feeding ecology, being useful on the identification of leftovers on feces and stomach contents. Hairs are the less damaged structures by digestive processes and nonetheless are the only clue for the identification of the prey in studies of feeding ecology of predators, since bones and tooth suffer heavy damage during the chewing process, being of a low diagnostic value. These factors show the importance of a better knowledge of the hair structure for prey or predator ecology studies. Also the hair trapping and identification has a important value in animal research bioethics, since the mammal surveys can be developed with hair-traps or scats/pellets without any harm or interference for the animals which have no risk to get addicted to the bait, which usually bias surveys, and minimizing the stress for being caught. The aim of the present thesis were the development of better techniques for the preparation of hair plates for collections and direct observations; the development of a identification key for Rain Forest rodents; and the morphometrical analysis of those mammals hairs for further comparison and analysis with biometrical data. There were developed 6 new techniques, being 3 for medulla pattern observation, and another 3 for cuticular impressions. Those techniques showed a higher success index on plate preparation, enabling the development of high level research on this field. / Doutor

This thesis describes a procedural hair generator that is able to generate hair from just a few hairs, called hair guides, which are directly modeled by a 3d artist. The procedural hair generator is a part of Stubble project -- a tool for hair modeling in Autodesk Maya. The procedural hair generator can generate hair during rendering, thus avoiding storage of hair geometry in a scene file, which makes the rendering process very efficient. Furthermore, hair can be generated interactively and displayed by OpenGL during modeling in Maya. Generated hair geometry is mainly defined by interpolation from the mentioned hair guides; however it is also influenced by many hair properties. These properties can change hair geometry using noise functions, define hair color, width and more. To determine hair root positions on a given triangular mesh I use my own mesh sampling algorithm that generates random samples on a triangular mesh according to a density defined by a 2-dimensional texture. My sampling algorithm uses an innovative way of sampling from a discrete probability distribution, which can be used in other applications than mesh sampling.

Introduction: Hearing loss affects over 500 million people worldwide and results from irreversible damage to inner ear hair cells. The only available treatment is cochlear implants, which may be unable to provide sensory input if neuronal connections are lost, as they are in mouse models. Thus, regeneration of hair cells offers the only permanent cure; however, such therapeutic intervention requires a detailed molecular understanding inner ear development and hair cell maintenance. During mouse development, there is a balance between proliferation and differentiation that not only determines the size of the ear, but also is needed to form a functional sensory unit. The fulcrum to this balance is N-Myc, a key transcription factor that acts as a node incorporating many upstream growth signaling pathways and funnels them to directly alter the cell cycle and at the same time inhibits differentiation. The loss of N-Myc results in major morphogenetic abnormalities, including a progressive loss of cochlear, despite their initial formation. Interestingly, N-Myc is present in inner ear hair cells after birth, long after proliferation in the inner ear ceased. In addition to N-Myc, L-Myc is co-expressed throughout development in the inner ear. This data suggests that N-Myc and L-Myc may play partially redundant roles both early during development and later in hair cells. Elucidating the relative importance of the Mycs and their interdependent roles in maintaining the balance between proliferation and differentiation may shed light on future hair cell regeneration avenues. Methods: We generated two Cre-LoxP lines, knocking out both N-Myc and L-Myc before (Pax2-Cre) and after (Atoh1-Cre) hair cell formation. We assessed the possibility of Myc redundancy through 3D reconstructions generated from confocal image stacks from E10.5-E18.5 and the effects of early Myc loss on the balance between proliferation and differentiation through a quantitative PCR study that assessed relative changes in gene expression, using the Pax2-Cre N-Myc f/f L-Myc f/f mice. We assessed organ of Corti development and functionality at P21 and four months of age in the Atoh1-Cre N-Myc f/f L-Myc f/f mice. Results: The development of the Pax2-Cre N-Myc f/f L-Myc f/f mutant ear was more severely impacted than the Pax2-Cre N-Myc f/f alone, as shown by an additional 50% reduction in size. Genes important to cell cycle maintenance were downregulated whereas differentiation transcription factors were initially downregulated but subsequently later upregulated to normal levels. In Atoh1-Cre N-Myc f/f L-Myc f/f mice, there were no defects in hair cell development. Discussion: There appears to be redundancy between N-Myc and L-Myc with N-Myc playing a more important role in inner ear formation. The late-onset defects seen in the Pax2-Cre N-Myc f/f mice appear to be a result of abnormal formation of hair cells due to the disruption in the balance between proliferation and differentiation much earlier on. This is the first time such a late-onset hair cell loss has been shown to be due to a defect sustained much earlier and is an important finding as the majority of people suffer from late-onset hearing loss. Additionally, these findings highlight the continued therapeutic importance in elucidating the molecular interactions controlling the delicate shift from a proliferating precursor to a differentiating cell.

The following research proposal was meant to identify concerns and desired resources for transracial foster families based on the perspective of social workers. This study utilized a qualitative design and included face-to-face interviews with social workers currently working at Ark Homes Foster Family Agency. Interviews included nine social workers who had clients who were transracial foster families. Data analysis included audio recordings and written documentation. Transcription of all interviews followed after data collection was received. Findings from this study showed that social workers working with transracial foster families felt culturally competent to provide information to their clients. This study also found that the majority of social workers did not feel a need for their agency to provide additional trainings in cultural competence and that bringing the topic up to their supervisor on a need-be basis was suitable. Policy implementation surrounding social workers and transracial foster families could include foster care placement stability. If policy was implemented that required foster parents to support their foster child’s racial identity on a weekly basis, then that could increase the bond between foster child and foster parent. Policy implementation in this way could minimize the disagreements between the foster child and foster parent and have an increased likelihood of placement stability.

The widespread expression of polypeptide growth factors from the earliest stages of embryonic development through to mature issues in the adult organism suggests an involvement in a reiterated developmental process affecting the underlying cellular growth and differentiation of many tissues. The hair follicle has taken on increased significance with the observation that many genetic mutations in these peptide growth factor genes affect its development. The targeted disruption of genes encoding members of the EpidermalGrowth Factor (EGF) and Fibroblast Growth Factor (FGF) families in the mouse has revealed a functional role for these proteins in the regulation of hair follicle growth. Experimental data and other factors are examined and results given. A second experimental system was used to determine if a functional relationship between certain peptide growth factors was conserved in the Merino sheep. The induction of a catagen-like state in the wool follicle and other epidermal changes associated with EGF treatment may be related to the transciptional induction of these peptide growth factors / Doctor of Philosophy (PhD)

Blonde hair is a potent and highly visible sign in western culture. Although the popularity and desirability of blonde hair in the West is well documented, since the 1950s, blonde hair has also generated many negative associations and these have contributed to myths around blondeness. In particular, women who dye their hair blonde find themselves in a paradoxical position; they simultaneously evoke desire and derision. This thesis uses the model of feminine masquerade outlined by Joan Riviere (1929) as a locus for discussing the transgressive potential of the knowing use of blondeness as a sign. When women wear blondeness in this way they embrace it as an oblique means to access privilege. This self-reflexivity allows women to enter sites of power that they are otherwise excluded from. Drawing on ideas of the carnivalesque, as described by Mikhail Bakhtin (1968), this thesis also proposes that the carnivalesque is employed by women in order to transgress patriarchal boundaries through an ironic masquerade of the archetypal blonde. These paradoxical meanings of blondeness are evoked in the work of performance artist Vanessa Beecroft. Beecroft stages both the reflexive awareness of today's blonde woman and the way in which she is shaped by socio-cultural forces beyond her control. Through reference to Beecroft's art, this dissertation builds upon the optimism and transgressive potential of Bakhtin's 'carnival' and Riviere's 'feminine masquerade' to re-present the identity/position of blonde women as one of agency and power.

Prenatal alcohol exposure is known to have many profound detrimental effects on human fetal development (fetal alcohol spectrum disorders), which may manifest into lifelong disabilities. Although hearing deficiency is a recognized effect, how alcohol affects the auditory/vestibular systems has not been well studied. This is the first study that used the zebrafish, Danio rerio, as a model organism to investigate morphological effects of alcohol on the developing octavolateral system (auditory, vestibular and lateral line). Zebrafish embryos of two hours post fertilization (hpf) were treated in 2% alcohol for 48 hours and screened at 72 hpf for morphological defects of the inner ear and lateral line neuromasts. Inner ear size and otoliths of zebrafish from both alcohol-treated and control groups were examined using light microscopy. Zebrafish were stained with fluorescent vital dyes to visualize lateral line hair cells using confocal microscopy. The size of neuromasts and length of kinocilia were measured using scanning electron microscopy. Results reveal that alcohol treatment during the early development impairs the formation of otoliths, neuromasts and their hair cells, as well as ear size and kinocilium length. We observed several otolith phenotypes including zero, one, two abnormal, two normal and multiple otoliths for alcohol-treated zebrafish. Fetal alcohol exposure appears to severely impact the size of both anterior and posterior lateral line neuromasts. Our results indicate that early fetal alcohol exposure most likely results in functional defects of the octavolateral system due to inner ear and lateral line dysmorphology.

Thesis (M.A.)--University of North Carolina at Greensboro, 2006. / Title from PDF title page screen. Advisor: Stephen Stallcup, Karen Weyler; submitted to the Dept. of English. Includes bibliographical references (p. 29-30, p. 61-62).