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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.
211

The role of Ten Eleven Translocation enzymes in the hair follicle mesenchyme

Ahmed, Aqib January 2022 (has links)
Epigenetic mechanisms play an important role during the morphogenesis of the hair follicle and the hair cycle. Work on hair regeneration is of importance as no products are available which can provide complete reversal of hair loss. Tet2 promotes DNA demethylation by the hydroxylation of 5mC to 5hmC which in turn causes gene transcription activation. Dermal papilla (DP) cells located within the hair follicle are responsible for the regulation of development and the growth of hair follicles. Fgf20 signalling controls commitment of the mesenchymal precursor cells to the DP progenitor lineage. An immature DP cells is then formed during maturation by Shh signalling which then stimulates these to differentiate into a DP cell by BMP and Wnt signalling. Methylated DNA can be bound by the proteins recruiting transcription corepressors. DNA methyltransferases (DNMT’s) can be degraded by decitabine which reverses gene silencing. Conditional knockout of Tet2 in mouse DP cells results in a delay in anagen initiation, suggesting Tet2 is involved in the telogen-anagen transition. Additionally, by using dermal fibroblasts and RA-DPAC (Dermal Papilla activating medium supplemented with retinoic acid), it was found that decitabine can increase plasticity in dermal fibroblasts and RA-DPAC can be used to accelerate a lineage change to DP cells which is supported by the significant increase in the DP specific gene expression. Examples include AlPl, LEF1, BMP4/6/7, FGF10, BMPR1A and PDGFA. Additionally, by way of siRNA and conditional Tet2 knockout data in dermal fibroblasts, it was found Tet2 regulates signature DP genes such as Bmpr1a, ALPL, Tcf4 and SOX2.
212

Physical and computational models of the gloss exhibited by the human hair tress : a study of conventional and novel approaches to the gloss evaluation of human hair

Rizvi, Syed January 2013 (has links)
The evaluation of the gloss of human hair, following wet/dry chemical treatments such as bleaching, dyeing and perming, has received much scientific and commercial attention. Current gloss analysis techniques use constrained viewing conditions where the hair tresses are observed under directional lighting, within a calibrated presentation environment. The hair tresses are classified by applying computational models of the fibres' physical and optical attributes and evaluated by either a panel of human observers, or the computational modelling of gloss intensity distributions processed from captured digital images. The most popular technique used in industry for automatically assessing hair gloss is to digitally capture images of the hair tresses and produce a classification based upon the average gloss intensity distribution. Unfortunately, the results from current computational modelling techniques are often found to be inconsistent when compared to the panel discriminations of human observers. In order to develop a Gloss Evaluation System that produces the same judgements as those produced from both computational models and human psychophysical panel assessments, the human visual system has to be considered. An image based Gloss Evaluation System with gonio-capture capability has been developed, characterised and tested. A new interpretation of the interaction between reflection bands has been identified on the hair tress images and a novel method was developed to segment the diffuse, chroma and specular regions from the image of the hair tress. A new model has been developed, based on Hunter's contrast gloss approach, to quantify the gloss of the human hair tress. Furthermore, a large number of hair tresses have been treated with a range of hair products to simulate different levels of hair shine. The Tresses have been treated with different commercial products. To conduct a psychophysical experiment, one-dimensional scaling paired comparison test, a MATLAB GUI (Graphical user interface) was developed to display images of the hair tress on calibrated screen. Participants were asked to select the image that demonstrated the greatest gloss. To understand what users were attending to and how they used the different reflection bands in their quantification of the gloss of the human hair tress, the GUI was run on an Eye-Tracking System. The results of several gloss evaluation models were compared with the participants' choices from the psychophysical experiment. The novel gloss assessment models developed during this research correlated more closely with the participants' choices and were more sensitive to changes in gloss than the conventional models used in the study.
213

Unravelling novel molecular targets for photobiomodulation in human hair follicle towards the development of more effective light-based therapies for hair growth

Buscone, Serena January 2017 (has links)
Light and optical techniques have made a profound impact on modern medicine both in diagnostics and in therapy. Therapeutic action of light is based on photomechanical, photothermal, photochemical and photobiological interactions, depending on the wavelength, power density, exposure time and optical properties of tissue and cells. Last decade experienced a growing rise of commercial devices for management of hair growth, where all of them are based on low levels of light resulting into photobiological, non-thermal interaction of photons with cells, a process that recently has received an official term ‘photobiomodulation’. However, the design and analysis of the reported clinical studies are highly debated in a wider scientific community. The picture is further complicated by a virtual lack of proof about the exact molecular targets that mediate the physiological response of skin and hair follicles (HF) to low levels of light. The goal of this project was to investigate the expression of light-sensitive receptors in the human HF and to study the impact of UV-free blue light on hair growth ex vivo. The expression of Cryptochromes 1 and 2 (CRY1, 2), Opsin 2 and 3 (OPN2 and OPN3), but not other Opsins 1, 4 and 5 was detected in the distinct compartments of skin and anagen HF. Evaluation of the physiological role of detected light-sensitive receptors on hair growth was performed by the modulation of photoreceptors activity in HF ex vivo model. HFs treated with KL001, a stabilizer of CRY1 protein that lengthens the circadian period, delayed HF anagen-catagen transition; while silencing of CRY1 induced premature catagen development accompanied by reduced cell proliferation. Silencing of CRY1 in the HF outer root sheath (ORS) cells in vitro caused downregulation of ii genes involved in the control of proliferation; including the cyclin dependent kinase 6 (CDK6). OPN3 also had a positive effect on metabolic activity and proliferation of the ORS cells in vitro. OPN3 silencing resulted in the altered expression of genes involved in the control of proliferation and apoptosis. Investigated CRY1, OPN2 and 3 greatly absorb in the blue to green-region of the visible spectrum. This led us to investigate the effect of blue light on HF growth. Daily treatment with blue light (453 nm, 3.2 J/cm2, 16 nm full width half maximum) prolonged anagen phase in HF ex vivo that was associated with sustained proliferation. In addition, blue light (3.2 J/cm2) significantly stimulated proliferation of ORS cells in vitro. This effect was abrogated by silencing of OPN3. To summarize, CRY 1, OPN 2 and OPN 3 are expressed in the distinct compartments of the HF, including HF stem cells. Blue light (453 nm) at low radiant exposure exerts a positive effect on hair growth ex vivo, potentially via interaction with OPN3. The further research should be conducted to decipher interactions between blue light and the investigated receptors in the HFs. In addition, the beneficial effect of blue light at low radiant exposure on hair growth raises a possibility of increasing therapeutic efficacy when combined with topical chemistry used for management of hair growth.
214

Avaliação do dano a haste capilar ocasionado por tintura oxidativa aditivada ou não de substâncias condicionadoras / Evaluation hair damage treated with oxidative hair dye under influence of conditioners agents

Gama, Robson Miranda da 10 January 2011 (has links)
A fibra capilar quando exposta aos tratamentos químicos apresentam danos em sua estrutura e, consequentemente, pode ocorrer alterações nas propriedades mecânicas, de superfície, de cor e térmica. O objetivo deste trabalho foi avaliar: a influência das substâncias condicionadoras PA1 (silanetriol (and) panthenol), PA2 (PEG-12 dimethicone) e PA3 (hydrolysed silk (and) hydrolysed milk protein (and) lactose) adicionadas as tinturas oxidativas de coloração loiro claro na proteção contra danos aos cabelos de coloração castanho claro, avaliando as propriedades mecânicas (tração à ruptura), de superfície (perda proteica, penteabilidade das mechas de cabelo a seco e a úmido), de cor (retenção de cor) e térmica (termogravimetria, termogravimetria derivada e calorimetria diferencial exploratória (DSC). Para selecionar o tipo de coloração da tintura oxidativa e do cabelo a serem empregados para as fases subsequentes, foi realizado ensaio de perda proteica, expressa em albumina, foram selecionados a formulação e o tipo de cabelo não-grisalho que apresentou maiores danos. Considerando os ensaios realizados, a aditivação de tinturas capilares oxidativas de coloração loiro claro com substâncias condicionadoras PA1, PA2 e PA3 melhoraram significativamente as propriedades de resistência à penteabilidade tanto a seco como a úmido, reduziram a perda proteica e a não interferiram na resistência de tração à ruptura, nas respostas das curvas termogravimétricas da fibra capilar avaliadas. Entretanto, nas análises de DSC os princípios ativos PA1 e PA2 inibiram a presença da degradação das fibras capilares entre 170,0 e 270,O°C, caracterizando maior proteção térmica à fibra capilar. Enquanto, na avaliação de retenção de cor das mechas de cabelo analisadas, pode-se concluir que a PA3 não interferiu nos parâmetros colorimétricos analisados, sendo os resultados estatisticamente iguais a TB (tintura oxidativa de coloração loiro claro); o processo de lavagem das mechas capilares interferiu nos parâmetros das coordenadas de cor Da* e Db*. / The hair fiber when displayed to the chemical treatments they present damages in its structure and, consequently, can occurred alterations in the mechanical properties, of surface, thermal and color. The objective of this work was to evaluate: the influence of conditioners agents PA1 (silanetriol (and) panthenol), PA2 (PEG-12 dimethicone) and PA3 (hydrolysed silk (and) hydrolysed milk protein (and) lactose) added to the oxidative hair dyes of coloration light blond in the protection against damages to the coloration Iight brown hair, evaluation the mechanical properties (traction to the rupture), of surface (protein loss, dry and wet combing), of color (color retention) and thermal (Differential Scanning Calorímetry (DSC), Thermogravimetric (TG) and Derivative Thermogravimetric (DTG) analysis). To select the types of oxidative hair dye and hair to be used for subsequent phases, was protein loss assay, equivalent as albumin, were selected the formulation and type of non-gray hair that presented more damage. Considering the tests, the additive of oxidative hair dyes with conditioner agents PA1, PA2 and PA3, significantly improved lhe properties of protein loss, dry and wet combing and didn\'t affect the traction to the rupture in the answers of the thermogravimetric curves of the hair fiber evaluated. However in the DSC analyses PA1 and PA2 presence inhibited the degradation of hair between 170.0 and 270.0 °C, featuring thermal protection to the hair fiber. While the assessment of color retention of the tress of hair analyzed, it can be concluded that no changes in the PA3 colorimetric parameters analyzed and the results were statistically equivalent to TB (oxidative hair dye light blond), the washing process of tress hair intervened wíth the parameters of the color coordinates Da* and Db*.
215

Avaliação do dano a haste capilar ocasionado por tintura oxidativa aditivada ou não de substâncias condicionadoras / Evaluation hair damage treated with oxidative hair dye under influence of conditioners agents

Robson Miranda da Gama 10 January 2011 (has links)
A fibra capilar quando exposta aos tratamentos químicos apresentam danos em sua estrutura e, consequentemente, pode ocorrer alterações nas propriedades mecânicas, de superfície, de cor e térmica. O objetivo deste trabalho foi avaliar: a influência das substâncias condicionadoras PA1 (silanetriol (and) panthenol), PA2 (PEG-12 dimethicone) e PA3 (hydrolysed silk (and) hydrolysed milk protein (and) lactose) adicionadas as tinturas oxidativas de coloração loiro claro na proteção contra danos aos cabelos de coloração castanho claro, avaliando as propriedades mecânicas (tração à ruptura), de superfície (perda proteica, penteabilidade das mechas de cabelo a seco e a úmido), de cor (retenção de cor) e térmica (termogravimetria, termogravimetria derivada e calorimetria diferencial exploratória (DSC). Para selecionar o tipo de coloração da tintura oxidativa e do cabelo a serem empregados para as fases subsequentes, foi realizado ensaio de perda proteica, expressa em albumina, foram selecionados a formulação e o tipo de cabelo não-grisalho que apresentou maiores danos. Considerando os ensaios realizados, a aditivação de tinturas capilares oxidativas de coloração loiro claro com substâncias condicionadoras PA1, PA2 e PA3 melhoraram significativamente as propriedades de resistência à penteabilidade tanto a seco como a úmido, reduziram a perda proteica e a não interferiram na resistência de tração à ruptura, nas respostas das curvas termogravimétricas da fibra capilar avaliadas. Entretanto, nas análises de DSC os princípios ativos PA1 e PA2 inibiram a presença da degradação das fibras capilares entre 170,0 e 270,O°C, caracterizando maior proteção térmica à fibra capilar. Enquanto, na avaliação de retenção de cor das mechas de cabelo analisadas, pode-se concluir que a PA3 não interferiu nos parâmetros colorimétricos analisados, sendo os resultados estatisticamente iguais a TB (tintura oxidativa de coloração loiro claro); o processo de lavagem das mechas capilares interferiu nos parâmetros das coordenadas de cor Da* e Db*. / The hair fiber when displayed to the chemical treatments they present damages in its structure and, consequently, can occurred alterations in the mechanical properties, of surface, thermal and color. The objective of this work was to evaluate: the influence of conditioners agents PA1 (silanetriol (and) panthenol), PA2 (PEG-12 dimethicone) and PA3 (hydrolysed silk (and) hydrolysed milk protein (and) lactose) added to the oxidative hair dyes of coloration light blond in the protection against damages to the coloration Iight brown hair, evaluation the mechanical properties (traction to the rupture), of surface (protein loss, dry and wet combing), of color (color retention) and thermal (Differential Scanning Calorímetry (DSC), Thermogravimetric (TG) and Derivative Thermogravimetric (DTG) analysis). To select the types of oxidative hair dye and hair to be used for subsequent phases, was protein loss assay, equivalent as albumin, were selected the formulation and type of non-gray hair that presented more damage. Considering the tests, the additive of oxidative hair dyes with conditioner agents PA1, PA2 and PA3, significantly improved lhe properties of protein loss, dry and wet combing and didn\'t affect the traction to the rupture in the answers of the thermogravimetric curves of the hair fiber evaluated. However in the DSC analyses PA1 and PA2 presence inhibited the degradation of hair between 170.0 and 270.0 °C, featuring thermal protection to the hair fiber. While the assessment of color retention of the tress of hair analyzed, it can be concluded that no changes in the PA3 colorimetric parameters analyzed and the results were statistically equivalent to TB (oxidative hair dye light blond), the washing process of tress hair intervened wíth the parameters of the color coordinates Da* and Db*.
216

Memento Mitten : Re-Collecting Human Hair as a Material

Ivarsson, Linnéa January 2020 (has links)
Memento Mitten is a project about seeing human hair from the perspective of sustainability as a viable alternative material. The project also aims to question our reluctance in Western Europe to use it in projects and innovations. It explores the process of transforming hair from waste into a functional piece (a mitten) by using traditional handicraft (hand carding, hand spinning and nålbinding) as a change agent in order to alter our perception of hair. Relating anthropologist Mary Douglas’ theory on dirt to the Freudian definition of ‘Das Unheimliche’ (The Uncanny) the project further examines and dissects the emotional aspects of Uncanniness and the anxiety we perceive when in contact with disembodied hair.  Leaning on Douglas’ theory on dirt I developed a framework for action that could potentially have the transformative ability to, when applied to creative practices, recontextualize hair from uncanny waste into an emotionally safe material. Utilizing auto-ethnographic documentation, physical exploration and participatory elements (through design interventions), four phases were identified: rejection (identifying hair as waste), re-collection (collecting hair), dissolution (taking apart the hair through acts like hand carding) and assimilation (putting the hair into a new context). These phases, which I titled The Altered Phases of Dirt, showed that they had the potential to move our inner margins of comfort beyond Uncanniness through the physical engagement found in handicraft.
217

Vliv probíhající gravidity na mechanické parametry vlasů / Changes in the mechanical parameters of women's hair during pregnancy

Skřontová, Marie January 2017 (has links)
Title: Changes in the mechanical parameters of women's hair during pregnancy Matters: We can look from different angles on the hair - as on a nanocomposite fiber and as on biomaterial changing with the origin and age. The hair doesn't differ only by lenght, stucture and color but also by diameter and shape. It reflects the overall health of the individual and all the processes in the organism of the individual and thus also the pregnancy. During pregnancy, hormonal changes take place which have an effect on the hair. Many women experience faster hair growth, extension and increased volume of the hair during pregnancy. This status is only temporary and lasts only to the childbirth. Aim: The aim of this work was to show the influence of pregnancy on mechanical parameters of hair and what direction this influence takes. Next, using questionnaires, to better solve the effect of particular pregnancy parameters on the hair, i.e. pregnancy order, sex of the child. Then, evaluate the whole problem using statistical tests and so make better sense of it. Methods: We'd selected a group of 64 pregnant women; hair samples were cut from them in the nape area each month throughout pregnancy. Each measurement started with evaluation of hair diameter with the use of optical microscope. Next, the hair had been...
218

Hårproduktion genom böjning av förtexturerade hårkort : En undersökning av modelleringsmetoder samt design av hår till spel / Virtual hair production for real-time applications: using curves to modify pre-composited hair-bands : A study on hair modeling and stylng for games

Stahl, Isac, Kardell, John January 2020 (has links)
Despite the importance of hair for characters in games, the process for creating realistic looking real-time hair is a highly difficult task that can only be performed by a few artists. As the industry is growing so does expectations of games graphics and the need for higher fidelity hairstyles. This paper sets out to explain current modeling techniques for hairstyling, and presents an alternate way for styling haircard models using curve deformers. Our Blende radd-on, based on this method is then previewed by industry professionals to evaluate their perception of the method’s effectiveness based on “control”, “time” and “preference”. Our conclusion is that per wisp curve based controls are easily learnt, relatively quick to use and gives adequate control over each haircard. The method therefore shows promise instream lining artists’ production pipelines. This test serves as a pilot for further exploration of curve based tools for production of real-time hair.
219

Vliv probíhající gravidity na mechanické parametry vlasů / Changes in the mechanical parameters of women's hair during pregnancy

Skřontová, Marie January 2017 (has links)
Title: Changes in the mechanical parameters of women's hair during pregnancy Matters: We can look from different angles on the hair - as on a nanocomposite fiber and as on biomaterial changing with the origin and age. The hair doesn't differ only by lenght, stucture and color but also by diameter and shape. It reflects the overall health of the individual and all the processes in the organism of the individual and thus also the pregnancy. During pregnancy, hormonal changes take place which have an effect on the hair. Many women experience faster hair growth, extension and increased volume of the hair during pregnancy. This status is only temporary and lasts only to the childbirth. Aim: The aim of this work was to show the influence of pregnancy on mechanical parameters of hair and what direction this influence takes. Next, using questionnaires, to better solve the effect of particular pregnancy parameters on the hair, i.e. pregnancy order, sex of the child. Then, evaluate the whole problem using statistical tests and so make better sense of it. Methods: We'd selected a group of 64 pregnant women; hair samples were cut from them in the nape area each month throughout pregnancy. Each measurement started with evaluation of hair diameter with the use of optical microscope. Next, the hair had been...
220

Multi-flex neo-hybrid identities : liberatory postmodern and (post) colonial narratives of South African women's hair and the media construction of identity

Le Roux, Janell Marion January 2020 (has links)
Thesis (Ph.D. Communication Studies)) -- University of Limpopo, 2020 / Hair has been a marker of identity that communicates issues of race, acceptability, class and beauty. Evidence of this was during colonialism and apartheid where South African identities were defined by physical characteristics such as the texture of one’s hair, and the colour of one’s skin. Whiteness was the epitome of beauty which came with certain privileges. Non-White bodies were defined as part of a particular narrative that saw them as well as their hair as inferior to that of White bodies. Academic literature continues to engage African hair from the perspective of a colonial legacy through a postcolonial lens. This study, however, asserts a shift in engaging African hair and introduces an African identity which is re-empowered and liberated through agency and choice, and active participation in the construction of its own identity. This shift in engagement also relinquishes the African identity’s association with the dominant narrative of its conformity to a single European ideology of beauty and identity by introducing a (post)colonial, postmodern theory of a Multi-flex, Neo-hybrid identity which forms part of the theoretical framework of this study. This study draws on the theoretical positions of postmodern theory about the concepts of ‘self’ and identity. It engages interpretations of postmodernism and ‘self’ through the works of Kenneth Gergen and Robert Lifton who provide critical theoretical insight into postmodernism and identity. It also engages critical scholars such as Homi Bhabha, Franz Fanon, Kwame Appiah, Charles Ngwenya and Achille Mbembe, amongst others. Through this theoretical lens, I examine the role of the media in the presentation of the panoply of hair (styles) to South African women in the process of constructing a fluid, flexible and hybrid identity that decentres the ideology of rigid racial identity. I also critically investigate whether non-White women who lived during the colonial-apartheid era and those born in a free democratic era share this multi-flex, neo-hybrid identity of the postmodern woman. Thus this study aims to critically explore social narratives of South African women’s hair and how the media perpetuate the construction of a new postmodern African female identity within the backdrop of the commodification of hair and identity in a globalised market and media environment. Coupled with an interpretivist paradigm, a phenomenological v approach was adopted for this study. Data was collected from print media content material namely, DRUM Hair magazine (editions 2014-2019) due to the assortment of hairstyles and identities it provides for African women. Data was also collected in the form of semi-structured interviews/personal accounts/stories presented as phenomenological narratives from colonial-born Coloured and colonial-born Black female participants. Focus group interviews were conducted on post-apartheid/born-free Coloured and Black female South African participants to understand how these women construct their identities through hairstyle choices and the impact this has on the (re)presentation of their identities within the global beauty market environment. These diverse participants aged from 18 to 104 allow me to trace, if any, the changes in perception of hair and hairstyles from colonial-apartheid South Africa to the new and free post-apartheid South Africa. The results of the study show that media enable the African woman to construct a postmodern identity through the multiplicity of hairstyles/identities available to her. It also provides the African woman with the tools to create various identities for herself through the diversity of hairstyles available to her. The African woman who is exposed to an assortment of hairstyles can navigate from one identity to the next without being loyal to one identity which is typical of the postmodern self. Another finding is that coloniality seems to continue to shape the identities of women born during the colonial apartheid era. But for those born during the (post)colonial and post-apartheid era, they embrace a navigatory form of hybridity that is not loyal to one identity but explores various forms of identity, which the market place affords them and the media perpetuate in the construction of multi-flex, neo-hybrid and postmodern identities. The implication of this study is that it is liberating since it allows us to critically review our identity and what we deem as beautiful and to question the daily choices we make not only with our hairstyles but with fashion, food and other cultural elements that shape our performance of identities. / National Institute for the Humanities and Social Sciences (NIHSS) and South African Humanities Deans Association (SAHUDA)

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