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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
321

Raman spectroscopic analyses of preserved historical specimens of human hair attributed to Robert Stephenson and Sir Isaac Newton

Edwards, Howell G.M., Hassan, N.F., Wilson, Andrew S. 23 August 2004 (has links)
No / The Raman spectra of two historical specimens of human hair attributed to the engineer Robert Stephenson and scientist Sir Isaac Newton, preserved in private collections are reported. Comparisons are made with the Raman spectra of modern hair specimens and with hair from archaeological excavations. The hair spectra collected with a laser excitation of 785 nm are of a better quality than those collected using 1064 nm. The historical hair specimens are remarkably well-defined spectroscopically in terms of the amide I vibrational mode and the ν(SS), ascribed to a predominantly gauche–gauche–gauche CSSC conformation. The contrast with degraded hair specimens recovered from archaeological excavations is striking. The presence of a weak feature near 2590 cm−1 in the hair samples attributed to a ν(SH) vibration could be indicative of a reduction process operative on the CSSC cystine keratotic linkages and a possible origin of this is bacterial biodegradation identified histologically. This study demonstrates the molecular information available from non-destructive Raman spectroscopic analysis from single hair shafts or small bundles of fibres which complements information available from histological and destructive analytical techniques for rare biological specimens subjected to conservation or curation procedures in museums or private collections.
322

Towards an Understanding of the Interaction of Hair with the Depositional Environment

Wilson, Andrew S., Dixon, Ronald A., Edwards, Howell G.M., Farwell, Dennis W., Janaway, Robert C., Pollard, A. Mark, Tobin, Desmond J. January 2001 (has links)
No / There is developing interest in the analytical use of human hair from archaeological contexts in key research areas such as DNA, trace elemental and isotopic analyses. Other human tissues, especially bone, that have been used for trace element, isotopic and DNA analyses have had extensive study concerning their diagenesis, but this has not been done for hair. Consideration must be given to the complex interaction of hair with its buried environment, thereby laying a firm basis for the use of hair in future research. Since human hair is known to survive under a diverse range of environmental conditions, a pilot study has investigated the basic processes of hair degradation, using samples from different climatic zones and burial types. Variation in the degree of preservation of archaeological hair was characterized by light microscopy, electron microscopy, and FT-Raman spectroscopy, relating morphological change of the surface and internal structure of hair to its biochemical integrity. The results demonstrate a breakdown of cortical cell boundaries and disruption of the cuticular layering, coupled with infiltration of material from the burial matrix that suggests a progressive loss of cohesion that is in part due to microbiological activity. Medullated hair is shown to be more susceptible to physical breakdown by providing two routes for microbial and environmental attack. At the molecular level the proteinaceous component undergoes alteration, and the S-S cystine linkages, responsible for the strength and resilience of hair in living individuals, are lost.
323

The Degradation of Human Hair Studied by FT-Raman Spectroscopy

Edwards, Howell G.M., Farwell, Dennis W., Wilson, Andrew S. January 1998 (has links)
No
324

Demographic characteristics and association of serum Vitamin B12, ferritin and thyroid function with premature canities in Indian patients from an urban skin clinic of North India: A retrospective analysis of 71 cases

Sonthalia, S., Priya, A., Tobin, Desmond J. 12 May 2017 (has links)
Yes / Background: The incidence of self-reported premature hair graying (PHG) seems to be on the rise. PHG has a profound impact on the patient's quality of life. It remains an incompletely understood etiology with limited and modest treatment options. Aim: The evaluation of the demographic and clinical profile of patients with premature canities, and exploration of the association of this entity with certain systemic disorders suspected to be related to its etiology. Methods: Seventy-one cases of premature canities (onset noticed by patients before 25 years of age) presenting to an urban skin clinic in Gurugram, India, between September 2012 and September 2015 with this complaint were retrospectively analyzed. The patient records were retrieved that provided details of the onset, duration and pattern of involvement, history, and examination findings (scalp, cutis, and general physical). Since all these patients had been screened for anemia, thyroid disorder, fasting blood glucose, and Vitamin B12 levels at the time of presentation, these parameters were also available for analysis. Results: The mean age at onset of graying was 10.2 ± 3.6 years (range: 5–19 years), with an almost equal gender distribution. The earliest age of onset recorded was 5 years. A positive family history of PHG (at least one of the biological parents or siblings) was obtained in 64 (90.1%) of the cases. The temporal regions of the scalp (35.2%) were most commonly involved followed by the frontal region (18.3%). Hypovitaminosis B12 and hypothyroidism showed significant association with the disorder, whereas anemia, serum ferritin, and fasting blood glucose did not. Conclusion: The age of onset of hair graying can be as low as 5 years. Temporal and frontal areas are the most commonly involved sites. A strong family history, Vitamin B12 deficiency, and hypothyroidism are strongly associated with PHG. Larger case–control studies are mandated for discerning the correlation of these and other risk factors with PHG.
325

Androgens trigger different growth responses in genetically identical human hair follicles in organ culture that reflect their epigenetic diversity in life

Miranda, Benjamin H., Charlesworth, Matthew R., Tobin, Desmond J., Sharpe, David T., Randall, Valerie A. 2017 October 1918 (has links)
Yes / Male sex hormones-androgens-regulate male physique development. Without androgen signaling, genetic males appear female. During puberty, increasing androgens harness the hair follicle's unique regenerative ability to replace many tiny vellus hairs with larger, darker terminal hairs (e.g., beard). Follicle response is epigenetically varied: some remain unaffected (e.g., eyelashes) or are inhibited, causing balding. How sex steroid hormones alter such developmental processes is unclear, despite high incidences of hormone-driven cancer, hirsutism, and alopecia. Unfortunately, existing development models are not androgen sensitive. Here, we use hair follicles to establish an androgen-responsive human organ culture model. We show that women's intermediate facial follicles respond to men's higher androgen levels by synthesizing more hair over several days, unlike donor-matched, androgen-insensitive, terminal follicles. We demonstrate that androgen receptors-androgen-activated gene transcription regulators-are required and are present in vivo within these follicles. This is the first human organ that involves multiple cell types that responds appropriately to hormones in prolonged culture, in a way which mirrors its natural behavior. Thus, intermediate hair follicles offer a hormone-switchable human model with exceptional, unique availability of genetically identical, but epigenetically hormone-insensitive, terminal follicles. This should enable advances in understanding sex steroid hormone signaling, gene regulation, and developmental and regenerative systems and facilitate better therapies for hormone-dependent disorders.
326

The battle of the bulge: re-evaluating hair follicle stem cells in wound repair

Garcin, C.L., Ansell, David 06 May 2020 (has links)
No / The hair follicle has an established role in wound re-epithelialisation, a phenomenon that has been appreciated since at least the first half of the last century. The bulge niche, one location of hair follicle epithelial stem cells has been of particular interest to researchers over recent years, with numerous studies showing its ability to directly contribute to epidermal repair. However, recent work has highlighted other progenitor regions of the hair follicle that appear to act as stem cells during epidermal repair. In addition, several studies within the last 12 months have questioned the importance of the bulge during re-epithelialisation, producing conflicting literature. Here we provide a new model to demonstrate how several important differences in experimental design between studies could account for these seemingly opposing findings, which may have implications for how future studies are conducted.
327

Let Her Be Shorn: 1 Corinthians 11 and Female Head Shaving in Antiquity

Montier, Curtis E. 12 1900 (has links)
In 1 Corinthians 11:3-15, Paul writes that if a woman is to be so immodest as to wear her hair uncovered while praying or prophesying in a Christian assembly she might as well shave her head. Paul instructs the Corinthians that it is “one and the same” for a woman to have her head shaved and for her to unveil her hair. There is a large body of works cataloging the modesty standards in Hellenistic Greece but Paul’s reference to head-shaving remains obscure. This thesis looks to find the best explanation of Paul’s instructions. Research in this topic began as an investigation of a popular modern view. It can be found in conversation or a simple Google search, that women in Ancient Greece with their head shaved were prostitutes. Beyond being prostitutes, they were probably temple prostitutes. The evidence does not bear this out as there is no artwork depicting prostitutes, or indeed any women, with their heads shaved. Instead prostitutes are shown in Greek erotic art with both long and short hair, some with and some without head coverings. Literary sources do offer several different examples of women who had their hair cut off. There are examples of women shaving their hair off in Lucian’s The Syrian Goddess, Tacitus’ Germania, Plutarch’s Lycurgus and Roman Questions, several Talmudic sources, and On Fortune II, formerly attributed to Dio Chrysostom. By examining these sources in tandem with 1 Corinthians 11, the most probable impetus behind Paul’s writing relates to punishments for adultery.
328

Desenvolvimento de formulações cosméticas contendo óleos vegetais para proteção e reparação capilar / Development of cosmetic formulations with vegetable oils for hair care

Araújo, Lidiane Advíncula de 23 April 2015 (has links)
A fibra capilar está exposta a danos diários, como radiação solar, poluição, ato de pentear, higienização e fatores endógenos, além de tratamentos químicos, com o alisamento capilar. Assim, os produtos cosméticos possuem grande importância, uma vez que são desenvolvidos de forma a restaurar a fibra capilar danificada, que é mais porosa e hidrofílica, e proteger os cabelos de danos futuros. Os óleos vegetais destacam-se como importantes constituintes de produtos cosméticos, seguindo uma tendência mundial de incorporar ingredientes naturais em formulações para cuidados da pele e cabelos. Nesse contexto, o objetivo do presente trabalho foi desenvolver formulações cosméticas contendo óleos vegetais para a proteção e reparação capilar. Para tal, foram selecionados os óleos vegetais de abacate, argan e moringa, e desenvolvidas formulações contendo os óleos isolados ou associados, para aplicação em cabelos submetidos ao alisamento químico. Além disso, na etapa de pré-tratamento, foi incorporado um filtro solar às formulações. Em seguida, foi feito um direcionamento racional da escolha da formulação com maior potencial para ser utilizada nas etapas posteriores, usando a análise sensorial em mechas de cabelo e avaliação das propriedades mecânicas do fio. A formulação contendo a associação dos 3 óleos vegetais foi selecionada e, então, submetida aos estudos de estabilidade e reologia. Ao final das análises, as formulações mais adequadas à proposta do estudo foram selecionadas e aplicadas em mechas de cabelo submetidas a radiação solar, em duas etapas: pré e pós-tratamento, em relação à indução do dano. Com isso, o objetivo foi verificar se os cosméticos desenvolvidos teriam efeitos na prevenção ou recuperação dos danos causados pela radiação solar. Assim, foram avaliadas imagens obtidas por meio de Microscopia Eletrônica de Varredura, além da resistência mecânica do fio, dosagem da perda de triptofano por avaliação da intensidade de fluorescência e medidas da variação da cor da fibra capilar. Observou-se que os melhores resultados obtidos com os óleos vegetais foi na avaliação da resistência capilar, enquanto a adição do filtro solar teve impacto positivo também na redução da degradação do triptofano. Além disso, de maneira geral, os resultados indicam que o pré-tratamento foi mais eficaz em proteger a fibra capilar, quando comparado à capacidade de recuperar os danos por meio do pós-tratamento. Entretanto, o pós-tratamento foi importante para melhoria das propriedades sensoriais e para proteção de danos futuros. Com isso, dentre as formulações desenvolvidas, a que continha a associação dos óleos vegetais e do filtro solar, utilizada na etapa de prétratamento, foi a que levou aos melhores resultados, quando aplicada em mechas de cabelo. / Hair is a very important and distinctive feature that plays a major role in self perception and is part of the individual\'s identity. The hair fiber is exposed to daily damage, such as solar radiation, pollution and grooming, and endogenous factors, besides chemical treatments such as hair straightening. Therefore, cosmetic products are of great importance, since they are developed to restore the damaged hair fiber and to protect the hair from further damage. Vegetable oils stand out as important cosmetic ingredients, following a global trend to add natural ingredients in formulations for skin and hair care. In this context, the aim of this study was to develop cosmetic formulations containing vegetable oils for hair protection and repairing . For this purpose, three vegetable oils (avocado, argan and moringa oil) were selected for the development of cosmetic formulations for use in straightened hair. After that, the most suitable formulation was selected based on the results of sensory analysis and mechanical properties evaluation on hair tresses. The formulation containing the combination of 3 vegetable oils was selected and then evaluated in terms of stability studies and rheological behaviour. This way, the most appropriate formulations were selected and applied to strands of hair exposed to solar radiation in two different stages: pre and post-treatment in relation to the induction of the damage. Thus, the objective was to verify if the developed formulations would have effects in the prevention or repairing of solar damage hair. For this purpose, observations in Scanning Electron Microscopy, tensile properties evaluation, tryptophan degradation, and color measurements of the hair fiber were performed. Regarding the vegetable oils, the best results were found in the the tensile properties evaluation, whereas the addition of sunscreen had a positive impact on the assessment of the tensile properties evaluation and in the tryptophan degradation analysis, as well. Moreover, the results indicate that the pre-treatment was most effective than the post-treatment. Nevertheless, the posttreatment was important to improve the sensory properties. Thus, among the developed formulations, the one containing the combination of vegetable oils and the sunscreen, used in the pre-treatment, led to the best results when applied to hair tresses.
329

African American Women's Perceptions of Self-Value in the Transition to Natural Hair

Darden, Tekeilla 01 January 2019 (has links)
Scholars have reported on the upsurge of African American women wearing their kinky, or natural, hair and the issues surrounding their choices. The wearing of natural African American hair has not been fully accepted in mainstream society. The purpose of this phenomenological study was to explore how African American women understand self-value in the process of wearing their natural hair. The ethnic and racial identity model, critical race theory, and the strong Black woman collection were the conceptual frameworks used to connect identity, race and racism, and a collective vulnerability to the African American woman's hair journey. The study included 9 women who identified as being African American and as having transitioned to wearing their natural hair. The study was an integrative phenomenological analysis using in-depth interviews to explore subjective experiences to garner information about how African American women perceive self-value during, or after, transitioning to wearing natural hair. Data were coded with the participant's own words to formulate themes. According to study findings, participants experienced a succession of expanded self-values that began with values of self-awareness into values of self-love, values of self-confidence, and values of community. Psychologists could benefit from addressing the value of hair to African American women when considering cultural implications and formulating case conceptualization. These discussions address the acceptance of the natural traits to include hair of African American women and add a positive narrative with the goals of creating positive social change.
330

Body Depilation among Women and Men: The Association of Body Hair Reduction or Removal with Body Satisfaction, Appearance Comparison, Body Image Disturbance, and Body Dysmorphic Disorder Symptomatology

Boroughs, Michael Scott 01 January 2012 (has links)
Body depilation, or the reduction or removal of body hair, is a relatively new area of research inquiry. Although women in many industrialized cultures have engaged in depilation for several decades, this behavior has been documented only recently among men. Though originally thought to be widely practiced by women and only a small proportion of men, including athletes or bodybuilders, recent studies suggest that more men engage in body depilation than previously hypothesized. In fact, one recent study estimated the prevalence of men's body depilation at 83.7% which suggests that men are depilating at rates similar to women. Nevertheless sparse literature exists on the topic of depilation and its relationship to the overall body image of women and men, factors that predict depilation, and how the appearance of body hair may be related to body satisfaction, body image disturbance, and symptoms consistent with the clinical disorder known as Body Dysmorphic Disorder (BDD). Clinical issues thought to be associated with body depilation include physical injuries that put men and women at risk for infection as well as psychological risks including BDD. The goals of this research project were to: (a) further explore the depilation practices of both genders, (b) develop and evaluate three scales directly related to body depilation research, (c) identify predictors of depilation among both genders; (d) examine the correlates of depilation, (e) apply and further test theoretical models to explain depilation among both genders, and (e) examine demographic differences in body image disturbance and BDD while controlling for natural body hair growth. In support of the hypotheses, results indicated that men have greater levels of body hair growth at 12 discretely measured body sites compared to women, and that overall, body depilation prevalence is high (90.8%) among the individuals sampled. Depilation prevalence for women was 98.5% while 80.9% for men. Men were more likely to report depilation in the past, having ceased the behavior to allow natural hair growth to resume. Men were also significantly more likely to engage in hair reduction behaviors, e.g., trimming, rather than removing hair all together compared to women. Women reported a significantly greater frequency of injuries as a result of depilation, while men reported greater dissatisfaction with higher levels of chest or back hair growth. Instruments were developed and evaluated to measure depilation appearance comparison, depilation social norms, and body hair growth. In terms of predictors of depilation, appearance comparison was a predictor for both genders, while the drive for muscularity was a unique predictor for men. Theoretical paradigms associated with depilation included Social Comparison Theory, and in part, a belief that depilation is socially normative. Results also provided partial support for hypotheses related to gender, racial/ethnic, and sexual orientation differences in body image disturbance and BDD symptomatology. Overall, the results of this study provide support for the notion that body depilation is a key appearance and body image concern for both genders, though more so for men, but also suggest that more research is needed in order to better understand the role of the appearance of hair on the human body.

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