Dissertations / Theses on the topic 'Hair fibres'

This thesis is concerned with an investigation of human hair fibres, and is primarily directed towards forensic and cosmetic applications. Initially, a small study was conducted by the use of scanning electron microscopy in order to obtain a visual understanding of the human hair fibre. However, the main focus of the thesis is on the application of vibrational spectroscopy techniques for the investigation of single hair fibres (for forensic studies) or their bulk samples (for cosmetic studies). Previous research directed towards the forensic field, failed to discriminate human hair fibres with the aid of FT-IR microspectroscopy. In the present study, the same technique was again utilised but the spectral data was interpreted by chemometrics. A number of different hypotheses were proposed and tested. Initially, it was concluded that the best sampling site is the middle section of a single hair fibre. It has been shown that the variation between hair fibres from two individual sources exceeds that of several hair fibres from the same source. In general, it was concluded that human, single, hair fibres can be discriminated on the basis of gender, race and treatment (single treatments and multiple treatments). Samples with known history were used to build a reference set, and blind samples were used for validation. Overall, a success rate of about 83% was achieved. From the present results, it is concluded that FT-IR micospectroscopy followed by chemometrics is a powerful technique for the discrimination of human hair single fibres. For the cosmetic studies, FT-Raman and FT-IR/PAS, were used as complementary techniques to investigate the oxidation of hair fibres by varying the treatment times for permanently dyed hair. FT-Raman was used to study the oxidation of the S-S band, while FT-IR/PAS was employed to study the S=O oxidation states. The spectra were interpreted by the use of chemometrics. Overall, the results observed for the FT-Raman study were similar to those observed in the FT-IR/PAS. Curve fitting analysis, indicated that approximately 11 % of the disulfide bonds remain broken, while the rest are reformed. In addition, the ratio between the cystine to cysteic acid being formed, is 1.8. These observations agree with comments in the literature.

Human hair fibres are ubiquitous in nature and are found frequently at crime scenes often as a result of exchange between the perpetrator, victim and/or the surroundings according to Locard's Principle. Therefore, hair fibre evidence can provide important information for crime investigation. For human hair evidence, the current forensic methods of analysis rely on comparisons of either hair morphology by microscopic examination or nuclear and mitochondrial DNA analyses. Unfortunately in some instances the utilisation of microscopy and DNA analyses are difficult and often not feasible. This dissertation is arguably the first comprehensive investigation aimed to compare, classify and identify the single human scalp hair fibres with the aid of FTIR-ATR spectroscopy in a forensic context. Spectra were collected from the hair of 66 subjects of Asian, Caucasian and African (i.e. African-type). The fibres ranged from untreated to variously mildly and heavily cosmetically treated hairs. The collected spectra reflected the physical and chemical nature of a hair from the near-surface particularly, the cuticle layer. In total, 550 spectra were acquired and processed to construct a relatively large database. To assist with the interpretation of the complex spectra from various types of human hair, Derivative Spectroscopy and Chemometric methods such as Principal Component Analysis (PCA), Fuzzy Clustering (FC) and Multi-Criteria Decision Making (MCDM) program; Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Geometrical Analysis for Interactive Aid (GAIA); were utilised. FTIR-ATR spectroscopy had two important advantages over to previous methods: (i) sample throughput and spectral collection were significantly improved (no physical flattening or microscope manipulations), and (ii) given the recent advances in FTIR-ATR instrument portability, there is real potential to transfer this work.s findings seamlessly to on-field applications. The "raw" spectra, spectral subtractions and second derivative spectra were compared to demonstrate the subtle differences in human hair. SEM images were used as corroborative evidence to demonstrate the surface topography of hair. It indicated that the condition of the cuticle surface could be of three types: untreated, mildly treated and treated hair. Extensive studies of potential spectral band regions responsible for matching and discrimination of various types of hair samples suggested the 1690-1500 cm^-1 IR spectral region was to be preferred in comparison with the commonly used 1750-800 cm^-1. The principal reason was the presence of the highly variable spectral profiles of cystine oxidation products (1200-1000 cm^-1), which contributed significantly to spectral scatter and hence, poor hair sample matching. In the preferred 1690-1500 cm^-1 region, conformational changes in the keratin protein attributed to the α-helical to β-sheet transitions in the Amide I and Amide II vibrations and played a significant role in matching and discrimination of the spectra and hence, the hair fibre samples. For gender comparison, the Amide II band is significant for differentiation. The results illustrated that the male hair spectra exhibit a more intense β-sheet vibration in the Amide II band at approximately 1511 cm^-1 whilst the female hair spectra displayed more intense α-helical vibration at 1520-1515cm^-1. In terms of chemical composition, female hair spectra exhibit greater intensity of the amino acid tryptophan (1554 cm^-1), aspartic and glutamic acid (1577 cm^-1). It was also observed that for the separation of samples based on racial differences, untreated Caucasian hair was discriminated from Asian hair as a result of having higher levels of the amino acid cystine and cysteic acid. However, when mildly or chemically treated, Asian and Caucasian hair fibres are similar, whereas African-type hair fibres are different. In terms of the investigation's novel contribution to the field of forensic science, it has allowed for the development of a novel, multifaceted, methodical protocol where previously none had existed. The protocol is a systematic method to rapidly investigate unknown or questioned single human hair FTIR-ATR spectra from different genders and racial origin, including fibres of different cosmetic treatments. Unknown or questioned spectra are first separated on the basis of chemical treatment i.e. untreated, mildly treated or chemically treated, genders, and racial origin i.e. Asian, Caucasian and African-type. The methodology has the potential to complement the current forensic analysis methods of fibre evidence (i.e. Microscopy and DNA), providing information on the morphological, genetic and structural levels.

To date, an accurate understanding of the dynamics between the fibre's inherent geometric, mechanical and biological characteristics is deficient, affecting the reliability and robustness of hair data. There is also insufficient scientific clarity on the behaviour of curly hair, as most of the conclusions have been drawn from studies focusing on straight fibres. This research project aimed at gaining a more accurate understanding of the interrelationships between fibre curliness, strength and chemical bonding. In the current understanding of hair mechanics, curly fibres are considered to have a lower tensile strength than straight fibres. Furthermore, the current understanding of hair fibres does not associate hydrogen bonding with fibre shape. During experimentation, inadvertent observations suggested that current tensile methods ignore an important component of hair strength in curly fibres, and that hydrogen bonding supports fibre curliness. Intensive scrutiny of these observations led to fundamental contributions to the understanding of curly hair. Research tools included tensile, geometric, image, (FTIR) spectroscopic assessments, regression modelling and multivariate statistical analysis. Through this research, the role of hydrogen bonding in fibre curliness has been established. A theory is presented about extraordinary hydrogen bonds and the existence of hydrogen bond networks across the fibre matrix of curly hair. The theory has been substantiated experimentally via FTIR and weight measurements. The research also established the importance of the preelastic tensile region for curly fibres. It was clearly demonstrated that tensile strength of hair fibres is not only dependent on Young's modulus, but also on the fibre's inherent viscoelasticity, which appears to be important in curly fibres but becomes negligible with loss of curl. A model, developed from experimental observations and insights from similar biological fibres, is also presented. The model gives insights into ultrastructural changes at the early onset of fibre elongation. It also demonstrates the association between viscoelasticity and hydrogen bond networks. Taking this into consideration, a constitutive equation, developed to determine hair fibre strength accurately, is also presented in this work. This work does not replace current fibre curvature theories, but provides additional insights into hair shape, and therefore presents a fundamental contribution to curvature in human hair. It also highlights the shortcomings of current instrumentation methods that contribute to inaccurate conclusions regarding the strength of curly fibres.

The advent of nuclear DNA (nuDNA) analysis altered the way forensic biology was both practised and viewed by the forensic biologists, police, the legal system and the general public. The ability of nuDNA to individualise analysis of evidence and attach a statistical frequency ratio to the result, created an expectation that numerical objectivity should be part of all forensic analysis. There are few scientists who would disagree with both the need and desirability of objective measures of their results. Forensic hair examiners are no exception as indicated by numerous scientific publications specifically discussing means of objectively assessing hair and its characteristics. While mitochondrial DNA offers a partially objective measure of hair the result is destructive of the sample. A method that objectively supports the hair analysts' microscopic findings and is non destructive would be beneficial to forensic hair examination. This project attempted to develop an objective measure of hair analysis by using both traditional light microscopic comparative techniques combined with a high end digital imaging and image analysis capacity. Where objectivity equals an empirical set of numbers that can be manipulated for statistical significance, the comparative biological sciences such as histology, anthropology and forensic hair examination struggle. Forensic hair examiners have long acknowledged the difficulty, even inability, of assigning numerical values to the features that characterise one hair as being different from another. The human scalp hair is a "morphological" unit that is not readily split into component parts or even that these parts lend themselves to a number value. There have been at least nine separate studies which favourably compare the specificity of microscopic hair examinations. The challenge this study addressed was to appraise the use of numerical features in forensic hair examination, with particular emphasis on those features currently resisting numerical evaluation; specifically, colour and pigmentary characteristics. The techniques used were based on obtaining high quality digital images, and using the pixels inherent in the images to obtain numerical values of such features as colour and pigmentation. The project sample was taken from the telogen scalp hairs obtained from the hairbrushes of ten nominally brown haired Caucasians, both male and female. The focus was twofold: o Compare colour analysis of hair images from brown haired Caucasians within three standard, internationally recognized colour models, namely Red-Green-Blue (RGB) colour model; CIE XYZ Tristimulus (1931) colour model; and CIE L*a*b* (1976) colour model. o Using the same sets of digital images, undertake pattern recognition analysis both intra and inter individual hair samples. Discriminate analysis of the mean colour values collected for each of the inherent colour variables in the three colour models (red, green, blue; X, Y, Z and L*, a*, b*) indicated the RGB colour model gave the least separation of brown haired individuals; CIE XYZ and CIE L*a*b* separated several individuals for all their individual samples and several other individuals were mostly separated with only one of their own samples overlapping with another. Pattern analysis used a small area that represented the overall pigment patterning observed along the length of the hair shaft. This area was extracted from the digital image within V++ Digital Optics image analysis software. The extracted pattern piece was then compared with other sample images within the same hair and four other hairs from the same individual. Pattern extracts were also compared between person hair samples. The comparisons generated a set of numerical values based on the pixel number on the "x" axis of the whole image and the average difference between the extracted pattern image and the whole image. Analysis of this data resulted in log distributions when persons were matched with themselves. It was also possible to refer an unknown pattern extract to this distribution and based on probabilities, predict as to whether or not the unknown sample fell within any of the known sample's distribution.

Human hair profiling is an integral part of a forensic investigation but it is one of the most technically difficult subjects in forensic science. This thesis describes the research and development of a novel approach for the rapid identification of unknown human and other related keratin fibres found at a crime scene. The work presented here is developed systematically and considers sample collection, sample preparation, analysis and interpretation of spectral data for the profiling of hair fibres encountered in criminal cases. Spectral comparison of fibres was facilitated with the use of chemometrics methods such as PCA, SIMCA and Fuzzy Clustering, and the less common approach of multi-criteria decision making methodology (MCDM). The aim of the thesis was to investigate the potential of some vibrational spectroscopy techniques for matching and discrimination of single keratin hair fibres in the context of forensic evidence. The first objective (chapter 3) of the thesis was to evaluate the use of Raman and FT-IR micro-spectroscopy techniques for the forensic sampling of hair fibres and to propose the preferred technique for future forensic hair comparisons. The selection of the preferred technique was based on criteria such as spectral quality, ease of use, rapid analysis and universal application to different hair samples. FT-IR micro-spectroscopy was found to be the most appropriate technique for hair analysis because it enabled the rapid collection of spectra from a wide variety of hair fibres. Raman micro-spectroscopy, on the other hand, was hindered with fluorescence problems and did not allow the collection of spectra from pigmented fibres. This objective has therefore shown that FT-IR micro-spectroscopy is the preferable spectroscopic technique for forensic analysis of hair fibres, whilst Raman spectroscopy is the least preferred. The second objective (chapter 3) was to investigate, through a series of experiments, the effect of chemical treatment on the micro-environment of human hair fibres. The effect of bleaching agents on the hair fibres was studied with some detail at different treatment times and the results indicate a significant change in the chemical environment of the secondary structure of the hair fibre along with changes in the C-C backbone structure. One of the most important outcomes of this research was the behaviour of the fÑ-helix during chemical treatment. The hydrogen bonding in the fÑ-helix provides for the stable structure of the fibre and therefore any disruption to the fÑ-helix will inevitably damage the molecular structure of the fibre. The results highlighted the behaviour of the fÑ-helix, which undergoes a significant decrease in content during oxidation, and is partly converted to a random-coil structure, whilst the fÒ-sheet component of the secondary structure remains unaffected. The reported investigations show that the combination of FT-IR and Raman micro-spectroscopy can provide an insight and understanding into the complex chemical properties and reactions within a treated hair fibre. Importantly, this work demonstrates that with the aid of chemometrics, it is possible to investigate simultaneously FT-IR and Raman micro-spectroscopic information from oxidised hair fibres collected from one subject and treated at different times. The discrimination and matching of hair fibres on the basis of treatment has potential forensic applications. The third objective (chapter 4) attempted to expand the forensic application of FT-IR micro-spectroscopy to other keratin fibres. Animal fibres are commonly encountered in crime scenes and it thus becomes important to establish the origin of those fibres. The aim of this work was to establish the forensic applications of FT-IR micro-spectroscopy to animal fibres and to investigate any fundamental molecular differences between these fibres. The results established a discrimination between fibres consisting predominantly of fÑ-helix and those containing mainly a fÒ-sheet structure. More importantly, it was demonstrated through curve-fitting and chemometrics, that each keratin fibre contains a characteristic secondary structure arrangement. The work presented here is the first detailed FT-IR micro-spectroscopic study, utilising chemometrics as well as MCDM methods, for a wide range of keratin fibres, which are commonly, found as forensic evidence. Furthermore, it was demonstrated with the aid of the rank ordering MCDM methods PROMETHEE and GAIA, that it is possible to rank and discriminate keratin fibres according to their molecular characteristics obtained from direct measurements together with information sourced from the literature. The final objective (chapter 5) of the thesis was to propose an alternative method for the discrimination and matching of single scalp human hair fibres through the use of FT-IR micro-spectroscopy and chemometrics. The work successfully demonstrated, through a number of case scenarios, the application of the technique for the identification of variables such as gender and race for an unknown single hair fibre. In addition, it was also illustrated that known hair fibres (from the suspect or victim) can be readily matched to the unknown hair fibres found at the crime scene. This is the first time that a substantial, systematic FT-IR study of forensic hair identification has been presented. The research has shown that it is possible to model and correlate individual¡¦s characteristics with hair properties at molecular level with the use of chemometrics methods. A number of different, important forensic variables of immediate use to police in a crime scene investigation such as gender, race, treatment, black and white hair fibres were investigated. Blind samples were successfully applied both to validate available experimental data and extend the current database of experimental determinations. Protocols were posed for the application of this methodology in the future. The proposed FT-IR methodology presented in this thesis has provided an alternative approach to the characterisation of single scalp human hair fibres. The technique enables the rapid collection of spectra, followed by the objective analytical capabilities of chemometrics to successfully discriminate animal fibres, human hair fibres from different sources, treated from untreated hair fibres, as well as black and white hair fibres, on the basis of their molecular structure. The results can be readily produced and explained in the courts of law. Although the proposed relatively fast FT-IR technique is not aimed at displacing the two slower existing methods of hair analysis, namely comparative optical microscopy and DNA analysis, it has given a new dimension to the characterisation of hair fibres at a molecular level, providing a powerful tool for forensic investigations.

Human hair profiling is an integral part of a forensic investigation but it is one of the most technically difficult subjects in forensic science. This thesis describes the research and development of a novel approach for the rapid identification of unknown human and other related keratin fibres found at a crime scene. The work presented here is developed systematically and considers sample collection, sample preparation, analysis and interpretation of spectral data for the profiling of hair fibres encountered in criminal cases. Spectral comparison of fibres was facilitated with the use of chemometrics methods such as PCA, SIMCA and Fuzzy Clustering, and the less common approach of multi-criteria decision making methodology (MCDM). The aim of the thesis was to investigate the potential of some vibrational spectroscopy techniques for matching and discrimination of single keratin hair fibres in the context of forensic evidence. The first objective (chapter 3) of the thesis was to evaluate the use of Raman and FT-IR micro-spectroscopy techniques for the forensic sampling of hair fibres and to propose the preferred technique for future forensic hair comparisons. The selection of the preferred technique was based on criteria such as spectral quality, ease of use, rapid analysis and universal application to different hair samples. FT-IR micro-spectroscopy was found to be the most appropriate technique for hair analysis because it enabled the rapid collection of spectra from a wide variety of hair fibres. Raman micro-spectroscopy, on the other hand, was hindered with fluorescence problems and did not allow the collection of spectra from pigmented fibres. This objective has therefore shown that FT-IR micro-spectroscopy is the preferable spectroscopic technique for forensic analysis of hair fibres, whilst Raman spectroscopy is the least preferred. The second objective (chapter 3) was to investigate, through a series of experiments, the effect of chemical treatment on the micro-environment of human hair fibres. The effect of bleaching agents on the hair fibres was studied with some detail at different treatment times and the results indicate a significant change in the chemical environment of the secondary structure of the hair fibre along with changes in the C-C backbone structure. One of the most important outcomes of this research was the behaviour of the fÑ-helix during chemical treatment. The hydrogen bonding in the fÑ-helix provides for the stable structure of the fibre and therefore any disruption to the fÑ-helix will inevitably damage the molecular structure of the fibre. The results highlighted the behaviour of the fÑ-helix, which undergoes a significant decrease in content during oxidation, and is partly converted to a random-coil structure, whilst the fÒ-sheet component of the secondary structure remains unaffected. The reported investigations show that the combination of FT-IR and Raman micro-spectroscopy can provide an insight and understanding into the complex chemical properties and reactions within a treated hair fibre. Importantly, this work demonstrates that with the aid of chemometrics, it is possible to investigate simultaneously FT-IR and Raman micro-spectroscopic information from oxidised hair fibres collected from one subject and treated at different times. The discrimination and matching of hair fibres on the basis of treatment has potential forensic applications. The third objective (chapter 4) attempted to expand the forensic application of FT-IR micro-spectroscopy to other keratin fibres. Animal fibres are commonly encountered in crime scenes and it thus becomes important to establish the origin of those fibres. The aim of this work was to establish the forensic applications of FT-IR micro-spectroscopy to animal fibres and to investigate any fundamental molecular differences between these fibres. The results established a discrimination between fibres consisting predominantly of fÑ-helix and those containing mainly a fÒ-sheet structure. More importantly, it was demonstrated through curve-fitting and chemometrics, that each keratin fibre contains a characteristic secondary structure arrangement. The work presented here is the first detailed FT-IR micro-spectroscopic study, utilising chemometrics as well as MCDM methods, for a wide range of keratin fibres, which are commonly, found as forensic evidence. Furthermore, it was demonstrated with the aid of the rank ordering MCDM methods PROMETHEE and GAIA, that it is possible to rank and discriminate keratin fibres according to their molecular characteristics obtained from direct measurements together with information sourced from the literature. The final objective (chapter 5) of the thesis was to propose an alternative method for the discrimination and matching of single scalp human hair fibres through the use of FT-IR micro-spectroscopy and chemometrics. The work successfully demonstrated, through a number of case scenarios, the application of the technique for the identification of variables such as gender and race for an unknown single hair fibre. In addition, it was also illustrated that known hair fibres (from the suspect or victim) can be readily matched to the unknown hair fibres found at the crime scene. This is the first time that a substantial, systematic FT-IR study of forensic hair identification has been presented. The research has shown that it is possible to model and correlate individual¡¦s characteristics with hair properties at molecular level with the use of chemometrics methods. A number of different, important forensic variables of immediate use to police in a crime scene investigation such as gender, race, treatment, black and white hair fibres were investigated. Blind samples were successfully applied both to validate available experimental data and extend the current database of experimental determinations. Protocols were posed for the application of this methodology in the future. The proposed FT-IR methodology presented in this thesis has provided an alternative approach to the characterisation of single scalp human hair fibres. The technique enables the rapid collection of spectra, followed by the objective analytical capabilities of chemometrics to successfully discriminate animal fibres, human hair fibres from different sources, treated from untreated hair fibres, as well as black and white hair fibres, on the basis of their molecular structure. The results can be readily produced and explained in the courts of law. Although the proposed relatively fast FT-IR technique is not aimed at displacing the two slower existing methods of hair analysis, namely comparative optical microscopy and DNA analysis, it has given a new dimension to the characterisation of hair fibres at a molecular level, providing a powerful tool for forensic investigations.

Há um número crescente de indústrias no ramo de cosméticos atualmente, devido ao fato das pessoas se preocuparem mais com suas aparências e ansiarem por produtos de qualidade. Em decorrência desse fato as indústrias vêem investindo cada vez mais nas áreas de pesquisas e desenvolvendo tecnologia neste segmento. Este trabalho visa o estudo das fibras capilares e a interação das mesmas com uma formulação comercial contendo como ativo principal o biopolímero quitosana. Utilizou-se para tanto técnicas como microscopia eletrônica de varredura, microscopia ótica, microscopia de força atômica, análises térmicas (TG/DSC) e análise de espectroscopia de absorção na região do infravermelho. O estudo foi feito com cabelos caucasianos virgens (sem tratamento químico) e em cabelos caucasianos descoloridos. Os resultados evidenciaram melhorias na estrutura da fibra capilar. Pode-se também levantar dados como a rugosidade e a área cuticular da fibra, através desses dados verificou-se que a rugosidade na fibra capilar diminui e a área cuticular aumentou com o uso do produto. Foi observado também através da análise de infravermelho a presença da quitosana na fibra capilar.
Currently exists an increasing number of companies on the cosmetic market, due to the fact that people worry more about appearance and (to) desire (for) quality products. As a result the companies are investing more in this area and developing new technologies. The purpose of this work is to study hair fibers and their interaction with a commercial product containing chitosan which is the main ingredient in the formula of Kit Bio Film® Tânagra and techniques were used, such as MEV, optic microscopy, AFM, thermal analysis (TG/DSC) and infrared absorption spectroscopy. This study was realized with caucasian virgin hair (without any chemical process) and with caucasian uncolored hair. In all analyses improvement of the hair fiber structure was observed. Also observed data such as roughness and cuticle size showed an increase in roughness and a decrease of cuticle size.The presence of chitosan in the hair fiber was also observed by infrared analysis.

Fibers are ubiquitous in our visual world. Hair is an important part of our appearance, and we wear and use clothes made from various types of fibers. Computer graphics models that can accurately simulate light scattering in these materials have applications in the production of media such as movies and video games. They can also significantly lower the cost of textile design by allowing designers to design fabrics entirely in silico, render realistic images for feedback, and then fabricate final products that look exactly as designed.

Recent research has shown that renderings of the highest quality—those showing realistic reflectance and complex geometric details—can be obtained by modeling individual fibers. However, this approach raises many open problems. For hair, the effect of fiber cross sections on light scattering behavior has never been carefully studied. For textiles, several competing approaches for fiber-level modeling exist, and it has been unclear which is the best. Furthermore, there has been no general procedure for matching textile models to real fabric appearance, and rendering such models requires considerable computing resources. In this dissertation, we present solutions to these open problems.

Our first contribution is a light scattering model for human hair fibers that more accurately takes into account how light interacts with their elliptical cross sections. The model has been validated by a novel measurement device that captures light scattered from a single hair fiber much more efficiently than previous methods.

Our second contribution is a general and powerful optimization framework for estimating parameters of a large class of appearance models from observations of real materials, which greatly simplifies development and testing of such models. We used the framework to systematically identify best practices in fabric modeling, including how to represent geometry and which light scattering model to use for textile fibers.

Our third contribution is a fast, precomputation-based, GPU-friendly algorithm for approximately rendering fiber-level textile models under environment illumination. Using only a single commodity GPU, our implementation can render high-resolution, supersampled images of micron-resolution fabrics with multiple scattering in tens of seconds, compared to tens of core-hours required by CPU-based algorithms. Our algorithm makes fiber-level models practical for applications that require quick feedback, such as interactive textile design.

We expect these contributions will make realistic physically-based virtual prototyping a reality.

Ce travail consiste à de étudier les mécanismes survenant lors du frottement de surfaces textiles pileuses, en particulier dans les conditions du toucher humain. Le but final est de proposer une méthode permettant de concevoir des surfaces textiles qui aurait le toucher demandé. La première étape a été d'établir un modèle de frottement, et ensuite de le valider au moyen d’un tribomètre développé au laboratoire et enfin de l'appliquer à des surfaces textiles industrielles. Nous avons pu montrer que la force tangentielle à l'avant du frotteur est proportionnelle à la largeur de celui-ci et a une origine essentiellement mécanique, alors que la force sous le frotteur est proportionnelle à l’aire de contact entre le frotteur et la surface textile et est de nature mécanique (déformation de la surface) et adhésive. Nous avons pu alors définir et déterminer les contraintes de frottement à l’avant et sous le frotteur, caractéristiques de l’étoffe textile utilisée pour une charge normale fixe. La dépendance de la force de frottement à la vitesse de glissement a été mise en évidence. Une étude portant sur le frottement de macro-surfaces pileuses modèle a été réalisée pour expliquer cette viscosité. Des essais de frottement analogues à ceux de l’étude menée sur les surfaces réelles ont été réalisés. En faisant varier les paramètres cinématiques de l’essai ainsi que les propriétés physico-chimiques des fibres, nous avons pu déterminer que l'origine de la viscosité observée sur les surfaces textiles réelles provient majoritairement du frottement inter-fibres d’origine physico-chimiques
This work is to study the mechanisms occurring during friction of hairy textile surfaces, especially in terms of human touch. The final aim is to offer a method for designing textile surfaces with the required touch. The first step was to establish a model of friction, and then to validate it by means of a tribometer developed in the laboratory and then apply it to industrial textile surfaces. We have shown that the tangential force in front of the slider is proportional to the width of this one and has essentially a mechanical origin, while the friction under the slider is proportional to the contact area between the slider and the textile surface and is of a mechanical nature (surface deformation) and adhesive. We could then determine and define the friction stress in front and under the slider, characteristic of the textile fabric used for a fixed normal load. The dependence of the frictional force to the sliding velocity was highlighted. A study on the friction of model hairy macro-surfaces was performed to explain this viscosity. Similar tests to those of the friction study on real surfaces were performed. By varying the kinematic parameters of the test and the physico-chemical properties of the fibers, we were able to determine that the origin of the viscosity observed on real textile surfaces mainly comes from inter-fiber friction with physicochemical origin

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*.

Un theoreme remarquable de p. Deligne caracterise les categories tannakiennes symetriques sur un corps de caracteristique nulle de facon interne, c'est a dire sans donnee prealable d'un foncteur fibre. Sa preuve utilise un phenomene que nous appelons trivialisation. Nous donnons une construction directe des anneaux de trivialisation, que deligne construit par iterations. La verification des proprietes de trivialisation est une theorie du determinant et des cofacteurs dans une categorie tensorielle symetrique abstraite. Nous donnons egalement un critere de reductivite pour une algebre de hopf matricielle en caracteristique nulle, d'utilisation tres simple, qui repose sur une notion de conjugaison relle. Soit a une *-algebre de hopf unitarisable. Nous etablissons une equivalence de categories entre a-*-extensions galoisiennes munies d'une mesure de haar positive et *-foncteurs fibre sur les a-comodules unitaires. Nous montrons alors que de telles extensions galoisiennes possedent une c#*-norme, et nous introduisons la notion d'extension galoisienne d'un groupe quantique compact, pour laquelle la theorie de la mesure se deduit de la topologie. Enfin nous trouvons une nouvelle extension galoisienne pour les groupes quantiques gl#q(2) et u#q(2).

Sammanfattning I denna rapporten har en innovativ metod framtagits för att tillvarata textilt avfall. Fokus för projektet har legat mycket på praktiska framställningen. Fibrer som inte är spinnbara och inte längre har någon valutavärde återupplivas och får ett nytt liv. Istället för att slänga textilier till förbränning har det i arbetet presenteras en ny metod genom nonwoven som bidrar till återanvändning och materialåtervinning av textilier. Fler fördelar för metoden är att det går fort, det är billigt och återvunna material används. Konceptet är att producera ospunnet garn från nonwoven för att slutligen använda dessa i mattor som applikationsområde. Produktionen av nonwovengarn är en ny idé som behöver bli testad för att bestämma produktionsparametrarna för optimala garner.  Praktiska framtagningen genomgår processerna, öppning, kardning, sträckning,  mekanisk nålning, termisk värmning, tillskärning av garn och vävning. Vid start av projektet testades produktion av nonwovens genom olika metoder för 50/50 bomull/polyester, med enbart mekanisk nålning, med bara termisk värmning och en kombination av mekaniskt och termisk. Resultatet för att erhålla bästa kvalité för nonwovengarn var genom att använda sig av både nålning för att producera nonwovenremsor och värmning för att göra strukturen mer sammanhållen.  Det innebär att bindningsmaterial kommer bli en betydande faktor. För att undersöka de mekaniska egenskaperna för procentuella bindningsmaterialets effekt producerades nonwovenremsor i 75/25, 50/50, 25/75 bomull/polyester. Vid värmning användes temperatur i 170 ºC i 10 min, 170 ºC i 5 min och 160 ºC i 10 min. Produktion av 9 olika garntyper för att vid dragprovning analysera vilka parametrar som passar bäst till slutgiltiga garnet. Från testet visade graferna för brott och brott/tex ett tydligt svar, blandningen 50/50 bomull/polyester med termisk värmning 170 ºC i 5 min ger bäst resultat i de mekaniska egenskaperna.  Slutligen producerades garner utifrån parametrarna från dragprovningen. Garner av 50% bindningsmaterial med 170 ºC i 5 min framställdes för fibrer som är återvunna och inte längre kan spinnas. 50/50 återvunnen bomull/polyester och 50/50 avfallsfibrer/polyester samt en blandning av 50/50 återvunnen bomull med 50/50 avfallsfibrer/polyester sammanbundna i nålningsprocessen.  Slutsater från metoden har visat vara genomförbart och slut resultaten för mattan har blivit överförväntan. Konceptet har öppnat upp fler dörrar och framtida idéer till möjligheter till användningsområden för nonwovengarn, mattan är en av få produktionsområde. Projektet kan bli stort i framtiden och förhoppningvis har det en positiv påverkan som leder till mindre textilavfall.

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.

Com o aumento dos tratamentos químicos e/ou físicos nos cabelos aos quais são realizados mediante o uso de dispositivos térmicos, há uma maior preocupação a respeito dos danos causados aos cabelos por estes tipos de tratamentos. O conhecimento dos efeitos, benefícios e/ou malefícios, de ingredientes cosméticos em cabelos torna-se necessário, pois facilita a busca por produtos baseada no tipo de cabelo. O principal objetivo do trabalho foi a caracterização físico-química, analítica e térmica de mechas de cabelo de diferentes etnias (caucasiano, oriental e afro-étnico virgem e brasileiro virgem e descolorido) antes e após o uso de ingredientes cosméticos seguido de um tratamento térmico (utilizando piastra) e intercalando com lavagens. O estudo das amostras de cabelo e de uma amostra de queratina animal envolveu a utilização das técnicas de TG/DTG, DSC, análise elementar, FTIR, MEV e técnicas de avaliação de eficácia, como tensão/deformação, penteabilidade e quebra por escovação. A partir da TG/DTG, foi possível avaliar as etapas de decomposição térmica das amostras de cabelo virgem e de queratina animal e estas apresentaram um comportamento térmico semelhante entre si. O estudo cinético não isotérmico por TG mostrou que, dos diferentes tipos de amostras de cabelo virgem, o afro-étnico apresentou menor estabilidade térmica e o oriental foi o mais estável termicamente. Os resultados de DSC corroboraram os obtidos por TG, demonstrando que a amostra de cabelo afro-étnico apresentou temperatura de desnaturação térmica das cadeias de α-queratina menor (TD = 223°C) do que as amostras dos outros tipos de cabelo (TD = 236°C). As mechas de cabelo virgem e clareadas foram tratadas com formulações cosméticas contendo silicones e avaliadas quanto a eficiência destes na proteção térmica dos cabelos. Algumas delas mostraram eficiência na proteção térmica das cadeias de α-queratina, diminuindo o seu grau de desnaturação. Foi possível observar que a associação do calor da piastra com as lavagens sucessivas causou danos tanto à cutícula (conforme resultados de FTIR e MEV), como também, ao córtex dos cabelos (conforme resultados de DSC). Em alguns casos, os danos causados foram tão graves que as camadas mais superficiais da cutícula sofreram descamações. O estudo mostrou, também, que a eficiência da proteção térmica nos cabelos depende do tipo da formulação cosmética em que estes protetores estão incorporados e do estado em que os cabelos se encontram. A DSC permitiu a avaliação da modificação termicamente induzida das cadeias de α-queratina e sua posterior desnaturação. O estudo envolvendo a associação das diferentes técnicas apresentou-se viável na avaliação tanto dos danos causados aos cabelos quanto na eficiência dos ingredientes cosméticos na proteção térmica dos mesmos.
With the increase of chemical and/or physical hair treatments, there is an increased concern about the damage caused by the continued use of thermal equipment. This is due to products identified as \"progressive brush\", widely used by individuals of various types of hair, in order to straighten them that are employed with the mandatory use of piastra. Thus, knowledge about the effects, benefits and/or detriments, of cosmetic ingredients in hair of different ethnic groups becomes necessary because it facilitates the search for products based on the type of hair. The main objective this work was the physicochemical, analytical and thermal characterization of hair samples of different ethnic groups (caucasian, oriental, african-ethnic and brazilian type II) before and after the use of cosmetic ingredients followed by heat treatment, using piastra, interleaved by washes. For such purpose, it was used the TG/DTG, DSC, EA, FTIR, SEM and techniques for evaluation of effectiveness as stress/strain and combing. By TG/DTG, it was possible to evaluate the thermal decomposition events of hair and animal keratin samples and these showed a similar thermal behavior between them. The TG-non isothermal kinetic study showed that, from the different types of virgin hair samples, the african-ethnic hair samples had the lowest thermal stability and oriental hair samples were more thermally stable. The DSC results confirm the results obtained by TG, demonstrating that african-ethnic hair samples had thermal denaturation temperature of α-keratin chains (TD = 223°C) lower than the samples from other types of hair (TD = 236°C). The virgin and bleached hair tresses were treated with cosmetic formulations containing silicones and evaluated the efficiency of the thermal protection of the hair. Some of the formulations tested have shown to be efficient as to its protective effect on the degradation of the α-keratin chains, decreasing the degree of denaturation. It was observed that the combination of the heat of piastra with successive washes caused damage to the hair cuticle (according to the IR and SEM results) as well as the cortex of hair (according DSC results). In some cases, the damage was so severe that the most superficial layers of the cuticle suffered flaking. The study also showed that the efficiency of the thermal protection in the hair depends on the type of cosmetic formulation that these protectors are incorporated and the condition of the hair. DSC technique allowed monitoring of the thermally induced modification of the α-keratin chains and subsequent denaturation. The study of the combination of all the techniques, as presented, is feasible in measuring damage to hair and the efficiency of cosmetic ingredients in protecting them.

Orientador: Marcia Miguel Castro Ferreira
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Imagens são utilizadas na investigação científica há muito tempo, inicialmente apenas como ferramentas para a representação da prática científica, e após o surgimento das técnicas de microscopia, como instrumento para registro e análise instrumental. Com o aperfeiçoamento das técnicas de obtenção de imagens, cresceu a demanda por técnicas quantitativas e sistematizadas para extrair-lhes informações, e capazes de estabelecer critérios estatisticamente confiáveis para, por exemplo, detectar similaridades, padrões, classificar, e até mesmo gerar modelos preditivos. Neste trabalho, métodos quimiométricos foram utilizados como ferramenta quantitativa para a análise de imagens nível de cinza, utilizando como exemplos imagens de microscopia de força atômica de fibras capilares de diferentes classes. Fibras capilares são frequentemente utilizadas em clínicas, indústrias ambientais e análises forenses, para o diagnóstico de doenças, avaliação da exposição aos agentes tóxicos e poluentes e detecção de abuso de drogas. Para este trabalho foram utilizados dois conjuntos de dados: um deles formado por amostras de fibras caucasianas submetidas ao tratamento de descoloração e outro com fibras de diferentes etnias. O objetivo foi utilizar métodos quimiométricos para construir modelos classificatórios capazes de identificar corretamente novas imagens. Diversas estratégias foram testadas e os melhores resultados foram obtidos utilizando os métodos SIMCA (Soft Independent Modeling of Class Analogy), PARAFAC (Parallel Factor Analysis), MPCA (Multi-way Principal Component Analysis) e NPLS (Multi-way Partial Least Squares). Os modelos quantitativos apresentaram erros de calibração abaixo de 10% e erros de predição em torno de 10%. Com exceção de uma das aplicações, que é específica para fibras capilares, os outros métodos de análise de imagens propostos podem ser utilizados na análise quantitativa de qualquer tipo de imagem nível de cinza
Abstract: Images have been used in scientific investigation for a long time, initially as a tool for representation of the scientific practice and, after the microscopy development, as an instrument for registration and instrumental analysis. With the improvement of microscopic techniques, there was an increase on the demand for quantitative and systematic tools to extract relevant information from images and for techniques capable to establish reliable statistical approaches, for example, to detect similarities, patterns and for classification. In this work, multivariate methods were used as quantitative tools for the analysis of nível de cinza images of different classes of hair fibers. These images were obtained by atomic force microscopy. Hair fibers are frequently used in medical clinics, environmental industries and forensic analyses, for the diagnosis of diseases, evaluation of the exposure to toxic agents and pollutants, and detection of abuse of drugs. In this work two data sets were used: the first one contained caucasian hair fibers submitted to peroxide treatment and the second one contained fibers from different ethnic origin (oriental, african and caucasian). The goal was to use chemometric methods to build classification models capable to identify new images correctly. Several strategies were tested and the best results were obtained by using SIMCA (Soft Independent Modeling of Class Analogy), PARAFAC (Parallel Factor Analysis), MPCA (Multi-way Principal Component Analysis) and NPLS (Multi-way Partial Least Squares). The models presented calibration errors below 10% and prediction errors around 10 %. With exception of the descriptor analysis, which is specific for hair fibers images, the proposed methods can be useful for quantitative analysis of any kind of nível de cinza images
Doutorado
Físico-Química
Doutor em Ciências

How can we live and work with craft as people in an age of global climate crisis? What must we change in order to work empathically and in harmony with our surrounding world? While not in need to actively ensure our survival, it is easy for us to forget to stay humble to our own needs, thus taking our lives and our surroundings for granted. We forget our bodies and we forget the bodies of others, animals and objects alike. We forget that we need each other in order to become. This text is a complementary exploration in how awareness of the soul, body and Spirit may help bring back a balance that we've lost in town based cultures of the west. I am looking for balance as I twist fibre into thread and into rope and as I suspend rock- and human bodies into temporary sculptures. I look for inspiration in phenomenologist thought, alchemy, shamanism and daoism, as well as in the active making of craft and art. My work centers around telling stories, crafting and material exploration as well as bodily awareness and performance. In the work, body and material are synonymous concepts drifting in and out of each other, enabling and shaping each other, becoming together. I am looking to meet my surroundings not always on my own terms, but by changing, adapting and compromising myself. This helps bring an awareness that unites me with the bodies around me, placing me not above but amidst constant becomings.

A Hepatite Autoimune (HAI) é uma doença inflamatória crônica oriunda de autoimunidade, ocasionando fibrose hepática. O objetivo desse estudo foi verificar possíveis inter-relações entre HLA-G, BAMBI e processos inflamatórios/fibrogênicos hepáticos na Hepatite Autoimune, tanto em biópsias de pacientes pré quanto póstratamento com imunossupressores. Foram selecionadas noventa e cinco biópsias de pacientes do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto diagnosticados com HAI, associados ou não a depósitos de ferro no fígado. As biópsias foram submetidas à imuno-histoquímica para marcação das proteínas HLAG e BAMBI. As estatísticas foram determinadas pelos testes Mann-Whitney e correlação de Spearman. A expressão de HLA-G e de BAMBI se apresentou aumentados conforme o agravamento da inflamação e fibrose em pacientes pré- tratamento com boa ou má resposta ao tratamento. No entanto, a expressão de HLAG e de BAMBI foi reduzida nas biópsias pós-tratamento apenas nos pacientes bom respondedores (diminuição da fibrose). Não houve quaisquer relações entre as quantificações de HLA-G e BAMBI com o número de plasmócitos ou com depósitos de ferro no fígado tanto em pacientes pré quanto pós-tratamento. Os resultados sugerem que tanto HLA-G quanto BAMBI são imunorreguladores sensíveis à intensidade do processo inflamatório no fígado, tendo suas expressões aumentadas ou diminuídas de acordo com a demanda por substâncias que regulem compostos e células imunológicas na HAI. Sugerem também que o infiltrado plasmocitário não é regulado diretamente pelo HLA-G ou BAMBI, e que os depósitos de ferro no fígado não são capazes de influenciar nem o grau inflamatório, nem as expressões de HLAG e BAMBI.
Autoimmune Hepatitis (HAI) is a chronic inflammatory disease originating from autoimmunity, causing liver fibrosis. The objective of this study was to verify possible interrelations between HLA-G, BAMBI and inflammatory / fibrogenic hepatic processes in Autoimmune Hepatitis, both in pre and post-treatment immunosuppressive biopsies. Ninety-five biopsies of patients from the Clinical Hospital of the Medical School of Ribeirão Preto diagnosed with HAI, associated or not with iron deposits in the liver, were selected. Biopsies were submitted to immunohistochemistry for the labeling of HLA-G and BAMBI proteins. The statistics were determined by the Mann-Whitney tests and Spearman\'s correlation. The expression of HLA-G and BAMBI was increased as worsening of inflammation and fibrosis in pre-treatment patients with good or poor response to treatment. However, the expression of HLA-G and BAMBI was reduced in post-treatment biopsies only in patients with good responders (decreased fibrosis). There were no relationships between the quantifications of HLA-G and BAMBI with the number of plasma cells or with liver iron deposits in both pre and post-treatment patients. The results suggest that both HLA-G and BAMBI are immunoregulators sensitive to the intensity of the inflammatory process in the liver, their expressions being increased or decreased according to the demand for substances that regulate immune cells and compounds in HAI. They also suggest that plasmacytic infiltrate is not directly regulated by HLA-G or BAMBI, and that the liver iron deposits are not capable of influencing either the inflammatory grade or the expressions of HLA-G and BAMBI.

Les traitements thermomécaniques permettent une mise en forme temporaire et aisée de la chevelure, propriétés recherchées par les utilisateurs. Cependant, les effets obtenus ne sont pas toujours à la hauteur des attentes, notamment en raison d’une mauvaise tenue de la forme dans le temps et de possibles endommagements de la chevelure. Dans le but d’améliorer les appareils de coiffage existants, nous souhaitons comprendre les effets de ces traitements sur le cheveu, pour ensuite déterminer les conditions permettant d’atteindre la meilleure rémanence de la forme tout en minimisant la dégradation du cheveu. Pour ce faire, nous nous appuyons sur des expériences de traction, microdiffraction X et spectroscopie infrarouge. Tout d’abord, nous avons étudié l’organisation structurale de cheveux naturels. Nous avons mis en évidence une distribution de structure cœur – peau avec un cœur de structure régulière d’autant plus excentré que la courbure est marquée. Ensuite, nous avons dégagé les principaux paramètres sur. lesquels jouer lors de la mise en forme: température du mandrin, contrainte et durée d’application. Les effets de ces paramètres sur le comportement mécanique et la nanostructure du cheveu ont été évalués. Il ressort de notre étude que la contrainte de mise en forme est déterminante : nous avons défini la gamme de contraintes permettant de préserver la structure et les propriétés mécaniques du cheveu et celle occasionnant la dégradation du cheveu, voire une restructuration en feuillets bêta. Nous avons également évalué l’efficacité des différentes conditions de traitement à produire une forme durable dans le temps. En complément, nous nous sommes intéressés au mécanisme structural survenant lors de l’étirement de cheveux natifs ou préalablement traités, en couplant étirement continu d’un cheveu et analyse par microdiffraction X. Ainsi nous avons réussi à suivre l’évolution sous étirement d’une structure de cheveu transformée en feuillets bêta. Les résultats originaux obtenus au cours de ce travail, qui établissent un lien entre les mécanismes moléculaires et le comportement macroscopique du cheveu, permettent d’envisager le développement de nouveaux traitements thermomécaniques à l’échelle industrielle
Thermomechanical hair styling is preferred by users for easy and temporary reshaping of hair. However, the result is not always up to expectations, particularly due to poor shape stability over time and possible hair damage. In this work, we aim to improve hairstyling devices. To this end, we need to understand the effects of such treatments on hair in order to determine conditions which allow the best shape holding while minimizing hair damage. To achieve this, we use tensile testing, X-ray diffraction and infrared spectroscopy experiments. First, we studied the structural organization of natural hair. We highlighted a “core-skin” distribution of structures with a regular core which is all the more off-centered as curvature is high. Subsequently, we identified the main parameters of thermomechanical reshaping: temperature, stress and application time. Then, we evaluated the effects of these parameters on mechanical behavior and hair nanostructure. Our study shows that applied stress is a key factor: we defined stresses range allowing preservation of hair structure and its mechanical properties and the one leading to degradation or even driving to beta-sheets transition. Efficiency of the different treatment conditions in producing long-lasting shape over time was then evaluated. In addition, we analyzed the structural mechanisms that occur during stretching for native and pretreated hair: we used X-ray microdiffraction coupled with continuous stretching of hair. Consequently, we were able to monitor a beta sheet structure in hair during stretching. The original results obtained during this work, bridging internal molecular mechanisms and macroscopic behavior of hair, will allow to develop new thermomechanical treatments at industrial scale

Il mais rappresenta una delle colture più diffuse nel Nord Italia. Negli ultimi anni si è assistito ad un notevole incremento della superficie a mais legato soprattutto all'uso dell'insilato di mais come substrato per la produzione di biogas. Per questo motivo è necessario avere il maggior numero di informazioni possibili per migliorare le performance della coltura. In letteratura ci sono molti studi che valutano l’impatto dell’ambiente e del management sulle caratteristiche chimico nutrizionali e sul potenziale metanigeno del foraggio di mais ma non ci sono lavori che considerano entrambi i parametri. L’obiettivo della tesi è stato quello di investigare come il danno da grandine , la genetica e il momento di raccolta possano influenzare la composizione della pianta intera tradotta come potenziale metanigeno e valore nutrizionale del foraggio.
In the Po Valley the maize crop represent one of the most cultivated plant used for cattle feeding but in the last 10 years it is also used as biogas substrate. Considering the importance of this cultivation, there is the continuous need to obtain information about this plant with the aim to improve the crop performance. There are numerous studies investigating the impact of environmental aspects and management practices on chemical and nutritional composition, and methane production in the literature but very few that evaluate those parameters together. The general objective of this thesis is to investigate how hail damage, type of hybrid and the harvesting date affect the whole plant composition. To accomplish this, two specific objectives are posed: i) verify the effects of hail damage levels on yield, chemical and nutritional feature as well as on BMP of maize grown in the Po Valley; and ii) to evaluate the value of different hybrids for animal nutrition and methane production in anaerobic fermenters and as delaying harvesting after the usual stage of maturity affects these features. It was also aimed to verify if chemical composition and in vitro digestibility tests could allow to estimate methane yield potential in maize whole plant.

My work is a symptom of my ongoing quest to achieve immortality. I perpetually attempt to make permanent the traces we leave behind and the impressions we make upon each other. I use the body to portray boundaries – between the skin and the heart, comfort and disquiet, holding and letting go. The objects I make serve both as an agent for physical contact and as the commemoration of an ephemeral interaction. I create personal fossils, revealing the interstices formed when two bodies come into contact with one another. I use materials that reference endurance and longevity to record transient spaces whose edges continuously shift and whose membranes are particularly tenuous. This work is an ongoing catalog of the people in my life and my persistent efforts to hold on to those fleeting connections.

The drug abuse has created several problems, moral, social and economical, and does not have borders of social class, educational and religious. The chemicaltoxicological analysis is an indispensable resource to confirm the exposure of humans to these drugs. Depending on the purpose of analysis, various biological matrices can be used. Nowadays, hair is being recognized as a third fundamental biological sample for drug testing besides urine and blood. The collection of hair samples is simple, noninvasive being difficult its adulteration. The techniques based on the miniaturization of extraction have gained an important role on the world stage in relation to conventional techniques. Among these techniques, stand out to solid phase microextraction (SPME) and liquid phase microextraction (LPME). In this work, a analytical method was developed for determination of 9- tetrahydrocannabinol (9-THC), cannabidiol (CBD) and cannabinol (CBN) in human hair by headspace solid-phase microextraction (SPME) and hollow fiber liquid-phase microextraction (HF-LPME) using gas chromatography coupled to mass spectrometry, operating in tandem mode (GC-MS/MS). Initially, in step sample preparation, a small mass of hair (10 mg) was decontaminated with petroleum ether (2 mL) for 10 minutes of ultrasound application (3 times) followed by alkaline digestion (NaOH 1 M). A univariate design was used for the determination the better condictions of the parameters of HS-SPME: pH (10), temperature (90 °C), mass of hair (10 mg), extraction time (40 min), desorption time (10 min), ionic strength (Na2CO3), saturation time (10 min) and fiber (PDMS). For HF-LPME a fractional factorial design was used in the screening of some variables of this technique followed by central composite design in the evaluation of optimal values of variables. The variables assessed and the optimum values of these were: extraction solvent (butyl acetate), donor phase pH (14), agitation speed (600 rpm), extraction time (20 min), ionic strength (6.8 % m/v) and acceptor phase volume (20 μL). The methods were submitted to the validation process showed good linearity with coefficient of determination (R2) above 0.994. Precision was determined using two different concentrations (upper and lower limits of the linear range) and RSD values were between 6.6 and 16.4 % for HS-SPME and 4.4-13.7% for HF-LPME. Absolute recoveries were in the range 1.1 to 8.7 % (HS-SPME) and 4.4 to 8.9 % (HF-LPME). The limits of detection and quantification ranged between 7-62 pg mg-1 and from 0.0005-0.020 ng mg-1 to HS-LPME and HF-LPME, respectively. The 9-THC showed values of limits of quantification for both methods below the cut-off (LQ ≤ 100 pg mg-1). Finally, the methods developed and validated were applied in determining CBD, 9-THC and CBN in hair samples of patients from a center of rehabilitation for drug addicts. The concentrations were in the range of LD-0.018 ng mg-1 for CBD, LD-232 pg mg-1 for 9-THC and 9-300 pg mg-1 for CBN show the applicability of the method in monitoring studies. The concentration of cannabinoids in the samples ranged from limit of detection to 18 pg mg-1 for CBD, limit of detection to 232 pg mg -1 for 9-THC and 9 to 300 pg mg-1 to CBN demonstrate the applicability of the method in monitoring studies.
O consumo de drogas de abuso tem criado diversos problemas de ordem moral, social e econômica, além de não possuir fronteiras de classes sociais, educacionais e religiosas. A análise químico-toxicológica é um recurso indispensável para confirmar a exposição de pessoas a essas drogas. Dependendo da finalidade da análise, diversas matrizes biológicas podem ser utilizadas. Atualmente, o cabelo é reconhecido como uma das principais amostras biológicas para determinação de drogas, ao lado da urina e do sangue. A coleta de amostras de cabelo é um processo simples, não invasivo, sendo difícil sua adulteração. As técnicas baseadas na minituarização de extração têm ganhado um papel importante no cenário mundial frente às técnicas convencionais. Entre essas técnicas destacam-se a microextração em fase sólida (SPME) e a microextração em fase líquida (LPME). No presente trabalho, um método analítico foi desenvolvido para determinação de 9-tetraidrocanabinol (9- THC), canabidiol (CBD) e canabinol (CBN) em cabelo humano por microextração em fase sólida no modo headspace (HS-SPME) e microextração em fase líquida por fibra oca (HF-LPME) por cromatografia em fase gasosa e espectrometria de massas operando no modo tandem (GC-MS/MS). Na etapa de preparação da amostra, uma pequena massa de cabelo (10 mg) foi descontaminada com éter de petróleo (2 mL) por 10 minutos em ultra-som (3X), seguida de digestão alcalina (NaOH 1 mol L-1). Um planejamento univariado foi utilizado para o estudo das condições ótimas dos parâmetros de HS-SPME, tendo sido deferidos: pH (10), temperatura (90 ºC); massa de cabelo (10 mg); tempo de extração (40 min); tempo de dessorção (10 min); força iônica (Na2CO3); tempo de saturação (10 min) e fibra (PDMS). Para HF-LPME um planejamento fatorial fracionário foi empregado na triagem de algumas variáveis desta técnica seguido pelo planejamento composto central na avaliação dos valores ótimos das variáveis escolhidas: solvente de extração (acetato de butila), pH da fase doadora (14), velocidade de agitação (600 rpm), tempo de extração (20 min), força iônica (6,8 % m/v) e volume da fase aceptora (20 μL). Os métodos foram submetidos ao processo de validação demonstrando boa linearidade, com coeficientes de determinação (R2) acima de 0,994. A precisão foi determinada a partir dos limites inferior e superior da faixa linear apresentando valores de RSD entre 6,6 e 16,4% para HS-SPME e 4,4-13,7 % para HF-LPME. Recuperações absolutas foram de 1,1 a 8,7 % (HS-SPME) e 4,4 a 8,9 % (HF-LPME). Os limites de detecção (LD) e quantificação (LQ) foram de 7 a 62 pg mg-1 e 0,5 a 20 pg mg-1 para HS-SPME e HFLPME, respectivamente. O 9-THC apresentou valores de limites de quantificação para os dois métodos abaixo do valor de cut-off (LQ ≤ 100 pg mg-1). Finalmente, os métodos desenvolvidos e validados foram aplicados na determinação de CBD, 9- THC e CBN em amostras de cabelo de pacientes de centro de reabilitação de dependentes químicos. As concentrações dos canabinóides nas amostras variaram do limite de detecção a 18 pg mg-1 para CBD, do limite de detecção a 232 pg mg-1 para 9-THC e 9-300 pg mg-1 para CBN, demonstram a aplicabilidade do método em estudos de monitorização.

Dissertação de mestrado em Chemical Analysis and Characterisation Techniques
The human hair is constantly exposed to external aggressions by environmental factors or hair treatments that damage the hair fibres, affecting their physicochemical properties, mainly at the cuticle level. Therefore, there is a great need of preventing and repairing the hair fibres from these type of damages and the cosmetic industry keeps progressing in that direction. However, the majority of the techniques used for the evaluation of the hair damage are not sensitive nor precise enough to show damages on the hair surface, only showing drastic damages that reach the cortex of the hair fibres and giving images of the surface of the hair, not providing quantitative information. The aim of this study was to develop and validate cutting-edge techniques, not yet explored for hair analysis, to analyse the chemical and physical alterations occurring on the hair cuticle after chemical, heat and chemical + UV + pollution damage. When damaged, the surface of the hair becomes more irregular, having consequently an increase of the surface roughness. So, the hair surface roughness was analysed by Optical Profilometry and mainly two types of damage were analysed: chemical and heat. After testing and designing the methodology to evaluate the hair fibres surface through this technique, the final results showed an increase of the surface roughness for both types of damage when compared with normal hair. However, the differences were not statistically significant in the test conditions, not validating the methodology; still, it has a great potential and a higher number of samples could probably increase the results’ significance. Hair damage was also evaluated by ToF-SIMS and the protocol was designed to calculate the damage degree of the hair fibres through the methyl eicosanoic acid (18-MEA) level of degradation. The three types of damage prepared were analysed. Results showed a significant decrease of the mean peak intensity ratio 18-MEA/CN- on the damaged hair compared to normal hair for all three types of damage. The protocol designed for the ToF-SIMS was validated, showing to be a very sensitive, accurate and precise technique to evaluate the lipid changes on the hair surface induced by the different damages, showing significant differences that are not detected with the traditional techniques normally used.
O cabelo humano está constantemente exposto a agressões externas provocadas por fatores ambientais ou tratamentos capilares que danificam as fibras capilares, afetando as suas propriedades físicoquímicas, principalmente ao nível da cutícula. Pelo exposto, existe uma grande necessidade de prevenir e reparar o cabelo destes tipos de dano e a indústria cosmética progride nessa direção. Contudo, a maioria das técnicas utilizadas atualmente para a avaliação de possíveis danos no cabelo não são suficientemente sensíveis nem precisas para demonstrar o que acontece na superfície das fibras. Estas permitem apenas identificar danos drásticos que atingem o córtex das fibras ou apresentam somente imagens da superfície das fibras, não fornecendo informação quantitativa. O objetivo deste estudo foi desenvolver e validar técnicas inovadoras que ainda não tinham sido exploradas para a análise de cabelo, para estudar as alterações químicas e físicas que ocorrem na cutícula do cabelo após um dano químico, após um dano por calor e após um dano químico, por exposição à radiação UV e à poluição. Quando danificado, a superfície do cabelo torna-se mais irregular, havendo consequentemente um aumento da rugosidade. Assim, a rugosidade da superfície de fibras capilares foi analisada por Profilometria Ótica e sobretudo dois tipos de danos foram analisados: químico e por calor. Após testar e desenhar a metodologia para a avaliação da superfície das fibras capilares através desta técnica, os resultados finais mostraram um aumento da rugosidade da superfície para ambos os tipos de dano quando comparando com cabelo normal. As diferenças obtidas não foram estatisticamente significativas nas condições testadas, não validando a metodologia. Porém, esta técnica tem um grande potencial e um maior número de amostras poderá aumentar a significância dos resultados. Foi também estudada a avaliação por ToF-SIMS. O protocolo foi desenvolvido de forma a calcular quantitativamente o grau de dano das fibras através do nível de degradação do ácido 18-metil-eicosanóico (18-MEA), sendo que foram analisados os três tipos de dano. Os resultados mostraram uma diminuição do rácio do pico de intensidade 18-MEA/CN- no cabelo danificado comparado com cabelo normal para todos os três tipos de dano. Este protocolo foi validado, apresentando ser uma técnica muito sensível, exata e precisa para a avaliação de mudanças em lípidos na superfície do cabelo induzidas por diferentes danos.

The research of this work describes the degradation and conservation of archaeological hair fibers. Chapter I will be a brief overview, with Chapter II following with a literary review and definition of terms. Chapter III focuses on research centered on the structure of hair fibers and their physical and chemical attributes. It will also focus on the archaeological and historical evidence of hair fiber use by humans. This research will help form the backbone of the paper and experiments performed. The next chapter focuses on the degradation of hair fibers in different environments. Hair fibers left in underwater, open air, burial, and arid environments are monitored for degree of degradation and brittleness. The hair fiber types used are four commonly found hair fibers types: coarse wool, fine wool, mohair, and human hair. After deposition, conservation using silicone oil treatment is tested on the degraded hair fibers. When silicone oil treatment proves to be a viable conservation method, the technique is then be applied to two artifacts. The two artifacts used are a Victorian era watch fob made from human hair and hair fibers mixed with tar from the excavation of Kittern in Bulgaria. Chapter VII deals with the conclusions of the experiments as a whole. The degradation of the fibers in different environmental conditions show that burial in acidic sandy clay is the most detrimental to hair fibers, while hair fibers from arid, dry environments are brittle, but well preserved aesthetically. The silicone oil treatments are shown to be viable treatment methods with positive results for all of the fibers tested, including two artifacts, a Victorian watch fob made from human hair fibers and hair fibers mixed with a tar-like substance from the shipwreck Kittern in Bulgaria.

The hair shaft has increasing importance in bioarchaeology, since it is now possible to retrieve detailed biomolecular information on recent life history using individual fibres (e.g., on diet, drug use and DNA). Data on hair condition is an important cornerstone to ensuring that reliable information is obtained. The following study defines morphological features of degradative change in human terminal scalp hair using different microscopy techniques. Evidence of degradative change is translated into a ranked histology for assessing hair sample condition. The approach is applied to samples of cut modern scalp hair subjected to degradation under soil burial/simulated grave conditions.

Yes
Hair fibres are extraordinary materials, not least because they are exquisitely formed by each of the 5 million or so hair follicles on our bodies and have functions that cross from physiology to psychology, but also because they have well known resistance to degradation as seen in hair surviving from archaeological and historical samples [1]. Hair fibres on the head grow at around 1cm each month, together totalling approximately 12km of growth per person per year. Each fibre is incredibly strong for its small diameter; with one fibre typically holding 100g and together a well-formed ponytail [allegedly] has the collective strength to support the weight of a small elephant! Hair – and from here I mean scalp hair – is under constant scrutiny by each of us; whether it be style, split ends, the first few grey hairs or the collection of hairs in the shower that should be firmly attached - leading to the fear that is hair loss.

Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia
A construção em terra é uma técnica milenar, utilizada por várias civilizações por todo o mundo, estimando-se que uma parte considerável da população mundial viva em casas que usam a terra como material de construção. O desenvolvimento das tecnologias construtivas aliada a um forte crescimento da população ao longo dos últimos anos, contribuiu para um abrandamento e até esquecimento das técnicas tradicionais em terra. Deste modo, pretendeu-se com este trabalho, e no seguimento das preocupações ambientais que têm surgido nos últimos tempos, aproveitar um recurso disponível, e adicionar-lhe um material de baixo custo ambiental que permitisse adequar as suas características, de forma a poder ser aplicado numa eco-construção.Deste modo, o objectivo do presente trabalho é caracterizar e avaliar o modo como a introdução de um material, nomeadamente as fibras de cabelo, melhoram as propriedades mecânicas intrínsecas de um solo, em termos da sua resistência ao corte, à compressão e módulo de elasticidade, com vista à sua utilização como material de construção em aplicações estruturais na edificação considerada sustentável. Foi assim efectuado um estudo de caracterização dos vários materiais em estudo, solo e solo com fibras, sob condições de secagem distintas (em ambiente controlado e em estufa), e um estudo paramétrico em que são avaliadas as propriedades mecânicas (resistência e deformabilidade), do material através de ensaios laboratoriais de compressão e de corte. Do presente trabalho, conclui-se que a introdução das fibras de cabelo modifica o comportamento dos solos em análise, contribuindo para o aumento da sua resistência à compressão, do módulo de elasticidade e da sua ductilidade, verificando-se que em termos de deformabilidade esta melhoria foi mais perceptível para a secagem realizada em estufa. O desempenho ao corte dos solos reforçados não apresentou melhorias significativas.
Earth building construction is an ancient art, used by several civilizations all over the globe, and it is estimated that a considerable part of the world population still live in houses that use soil as the main building material. The improvement in constructive technologies combined with the considerable growth of the population in the recent years, has led to the decline of the traditional earth building techniques. Thereby, with the present assignment, and taking into consideration the environment concerns over the last few years, it is intended to use an available resource, and combine it with a material of low ecological cost, in order to improve his properties, so that it could be implemented in an eco-construction.So, in this way, the objective of the present dissertation is to evaluate the way how the incorporation of this material, namely the hair fibers, improve the mechanical properties of the soil, in terms of his shear and compression strength, as well of his elastic modulus, in order to be applied as building material in sustainable structures. Therefore, it was conducted a study to characterize the materials involved, soil and fibers, under different drying conditions (in a controlled environment and in a oven), and a parametric study to evaluate the mechanical properties (in terms of strength and deformability) of the material, by carrying out compression and shear tests.From this study, it is concluded that the addition of the hair fiber modifies the mechanical behaviour of the soils in analysis, leading to an increase of his compressive strength, elastic modulus and ductility, that in terms of deformability this improvement is more perceptible for the drying period in a oven. The shear performance of the reinforced soils didn’t show significant improvement.

Tese de doutoramento em Engenharia Química e Biológica
A forma do cabelo é uma característica indissociável da nossa imagem com grande impacto individual e social. Consequentemente, o desenvolvimento de produtos ou procedimentos para modelar a forma do cabelo tem sido um foco importante na indústria capilar. Como os processos físico-químicos atuais de modelação são potencialmente prejudiciais às suas fibras e couro cabeludo, existe um crescente interesse em novas abordagens que impliquem menos efeitos adversos. Uma compreensão mais profunda da biologia do folículo, juntamente com o desenvolvimento de melhores formulações serão essenciais para desenvolver novos cosméticos moduladores da forma do cabelo melhores e mais seguros. Assim, esta tese de doutoramento propõe, como objetivo principal, explorar uma nova abordagem para alteração da forma do cabelo: aplicação tópica no couro cabeludo de compostos que induzem, enquanto aplicados, o folículo a produzir uma fibra com forma diferente da natural. A produção deste biomaterial tão complexo (a fibra capilar) e o mecanismo pelo qual a sua curvatura é determinada é um tema que permanece ainda pouco esclarecido. No entanto, já está estabelecido que a forma do cabelo é determinada no folículo, especificamente no bolbo, como resultado direto da organização de diversos elementos estruturais que o compõem. O folículo é também reconhecido como um alvo privilegiado para sistemas de entrega de substâncias aplicadas topicamente. Para qualquer abordagem envolvendo fornecimento exógeno de um composto bioativo que vise modificar uma função biológica executada no bolbo, é essencial determinar qual ou quais os sistemas de entrega mais eficientes para alcançar a região desejada. Desta forma, um novo sistema de entrega de moléculas para o folículo, precisamente para a região do bolbo foi desenvolvido. Este sistema, apesar de ser menos complexo que outros sistemas particulados comuns, apresentou um desempenho igual, se não melhor, que os diferentes tipos de nanopartículas testados, atingindo o bolbo capilar. De seguida, fez-se uma triagem em larga escala de uma biblioteca de 1200 compostos, com perfil toxicológico bem definido e uma longa história de uso seguro em humanos, com o intuito de encontrar compostos capazes de alterar os níveis de expressão de determinados genes, previamente selecionados, em células primárias de uma camada específica dos folículos. Como resultado, 24 compostos foram escolhidos e validados, apresentando um efeito significativo na alteração dos níveis de expressão de vários genes potencialmente implicados na determinação da curvatura da fibra de cabelo. Assim, a formulação desenvolvida para entrega no bolbo e as melhores moléculas bioativas selecionadas foram acopladas para a realização de um estudo piloto in vivo da modelação da forma do cabelo. Neste ensaio clínico com intervenção de cosméticos, os cabelos de voluntários humanos, após aplicação tópica no couro cabeludo, durante cinco semanas, do Composto D ou do Composto F, cresceram mais lisos ou, se aplicado o Composto T ou o Composto X, cresceram mais encaracolados. Este efeito de alisar ou encaracolar foi mais percetível visualmente para os compostos D e X, respetivamente. Não foram observados efeitos adversos. Este trabalho contribui para um entendimento mais profundo sobre a determinação genética da forma do cabelo. As novas formulações moduladoras de aplicação tópica, aqui desenvolvidas, podem alterar a curvatura do cabelo humano de forma segura e eficiente, de dentro para fora. Foram, pois, criadas as condições para o desenvolvimento de procedimentos novos que constituem uma abordagem alternativa e inovadora para a modelação cosmética da forma do cabelo com eventual impacto comercial.
Hair shape is a highly perceptible feature with great individual and social impacts. Accordingly, the development of products or procedures to modulate the hair shape has been a major focus for the haircare industry. Since the current physical/chemical processes to change hair shape are potentially harmful to hair fibers and scalp, there is a growing interest on new approaches without adverse effects. The deeper understanding of hair follicle biology together with the development of improved formulations will be essential to create better and safer hair shape modulating cosmetics. Thus, this thesis work proposes, as major objective, a new approach to achieve hair shape modulation: the topical delivery of bioactive compounds that induce the follicle to produce a fiber with a different shape as the hair grows out of the scalp skin. The production of the highly complex biomaterial - the hair fibre, by the follicle and how shape is established are topics that remain poorly clarified. However, it is already established that hair shape is determined in the hair follicle, specifically in the bulb, as a direct result of the organization of its various structural elements. The hair follicle is also recognized as a privileged target for topically delivery of substances. For the purpose of this work, it was of major importance to understand, among the existing follicular delivery systems, the best possible choice to reach the desired region within the follicle. In this way, a new delivery formulation for the hair follicle, more specifically for the bulb region, was developed. This delivery system, despite being less complex than other established systems, performed as well as if not better than nanoparticles concerning the maximum follicle depth reached. Then, a large-scale screening of a chemical library of 1200 compounds, with well-defined toxicological profile and a long history of safe usage in humans, was performed to search for molecules with the ability to alter the expression levels of selected genes using primary cells from a specific hair follicle layer. As result, 24 compounds were selected showing a significant effect on down- or up-regulation of the expression levels of genes, previously found to be associated with different shape phenotypes. These best inducers and inhibitors were further validated. Taking into consideration all the in vitro/ex vivo data generated, the new formulation and the best four validated bioactive molecules were coupled to perform an in vivo pilot study on hair shape modulation. In this clinical trial with intervention of cosmetics, the hair of human volunteers, after topical application to their scalps of Compound D or Compound F, grew straighter and grew curlier when Compound T or Compound X were applied. This straightening and curling effects were visually more perceptible for the Compound D and Compound X, respectively. No adverse effects were reported. This thesis work contributes to a better understanding on how shape is genetically determined. The new cosmetic formulations here developed changed, after their topical application during five weeks, the hair shape of human volunteers from the inside out. The foundations were here created for the development of innovative procedures to modulate hair shape with the potential to impact the cosmetic haircare market.
Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/139522/2018

Background: Interpersonal touch is an irreplaceable contributor to our daily social life. It is a powerful tool for communicating emotions and, at this, enables the formation and maintenance of relationships. Affective touch is one of the first interactions in parent-child-dyads and contributes positively to the cognitive and social development of children and adolescents. In recent years, a group of nerve fibres was detected and identified as a key player in the perception of affective touch. These so-called C-tactile afferents are specialized in the perception of human-to-human caress-like touch. They are optimally activated/stimulated by light and slowly stroking touch at velocities between 1 and 10 cm/s (Löken et al., 2009). Interestingly, in a standardized experiment, these tactile stimulations are likewise hedonically rated and perceived as most pleasant. C-tactile afferents project to the insular as well as somatosensory cortex at a slow speed of around 1 m/s. The insular cortex is suggested to be involved in emotional processing and integration of sensory impressions, above else. Against this background, C-tactile afferents are characterized as key players in affective touch perception and mark an antipole to discriminative touch perception and Aβ-fibres. Affective touch contributes to the cognitive and social development in children (Field, 2010) and C-tactile mediated affective touch perception is altered in individuals with Autism Spectrum Disorder (Kaiser et al., 2016). First evidence further suggests a contribution of C-tactile afferents in the perception of erotic touch (Jönsson et al., 2015). Against this background of evidence for the role of C-tactile afferents, the social-touch-hypothesis was formed (Olausson et al., 2010), stating a contribution of C-tactile afferents in the formation and maintenance of interpersonal relationships. Still, only few approaches thus far have investigated the actual influence of C-tactile mediated affective touch perception on interpersonal behaviour. Individuals seem to differ in their peripheral and central characteristics and processing of affective touch, but a method to quantify these differences is still missing. Aim: In the presented articles, we first investigated the relationship between C-tactile mediated touch perception and sexual desire and behaviour (paper 1). Next, a procedure to test the individual preference of affective touch was developed and examined (paper 2). Recent research described C-low-threshold mechanoreceptors – the equivalent of C-tactile afferents in rodents - to be arranged around certain hair follicles (Li et al., 2011). We thus hypothesized in paper 3, that hair follicle density might be related to the density of C-tactile afferents and that affective touch perception might be predicted by hair follicle density. The article describes and examines a method for quantification of C-tactile afferents in humans. Materials and Methods: Papers 1 and 3 present the results of a psychophysical study conducted on a sample of relatively young and subjectively healthy participants at the Medical Faculty of Dresden University of Technology. In paper 3, the study is compared and analysed in relation to another study as part of a cooperation together with the University of Gothenburg (Sweden). The study design involved the standardized application of different CT-optimal as well as –suboptimal stroking stimuli on the forearm using a computer-assisted robotic device (Rotary Tactile Stimulator). The participants were asked to rate these tactile stimuli concerning different hedonic qualities (pleasantness and eroticism) on visual analogue scales. Sexual Desire and sexual behaviour were determined indirectly through questionnaires. The study design further included the Cyanoacrylate Skin Stripping Method that enables sampling of the upper layer of the skin – the stratum corneum. These samples were analysed light-microscopically in order to determine the hair follicle density of the participants. Paper 2 reviews a different study which was conducted at the Center for Social and Affective Neurosciences at the University of Linköping (Sweden). In this study, the Test of Preferred-Velocity was examined and validated as a measure of individually preferred touch stimuli on a sample of young and healthy participants. Analogous to the study design described in paper 1 and 3, tactile stimuli were applied using the Rotary Tactile Stimulator as well. The Test of Preferred-Velocity includes a forced choice paradigm in which the preferred stimulus out of different pairs needs to be reported. The paper describes two different set-ups applying the test: First, the Test of Preferred Velocity was validated and tested for retest-reliability. Afterwards, a short version of the test was applied on both the forearm and the palm of the hand, where it was each validated and compared in-between. The following measures were determined in order to analyse and describe the individual sensitivity for C-tactile mediated affective touch perception: In paper 1, the erotic touch differentiation was determined as the difference of eroticism ratings between C-tactile optimal (1 cm/s) and C-tactile suboptimal (30 cm/s) tactile stimuli. Pleasant touch awareness equally reflects the sensitivity for pleasant touch in paper 3. However, this measure further considers the average level of hedonic ratings. Results: C-tactile optimal stroking stimuli at velocities between 1 and 10 cm/s were perceived as both pleasant and erotic. This confirms the results of a previous study by Jönsson et al. (2015), where a contribution of C-tactile afferents to erotic touch perception was suggested. According to the presented hypotheses, a gender-specific relation between C-tactile mediated erotic touch perception and sexual desire as well as sexual behaviour could be detected (paper 1): Within the group of female participants, erotic touch differentiation was positively correlated with the desire for sexual interaction with a partner. In the male sub-group of participants however, erotic touch differentiation was negatively related to the actual frequency of sexual interactions with a partner in the course of the last month. The Test of Preferred-Velocity was reviewed as a reliable procedure for determining the individually preferred stroking velocity of C-tactile-targeted touch, presented a high test-retest-reliability and was validated with the hedonic ratings of the participants (paper 2). The short version of the test presented equally reliable features and was related with the hedonic ratings when tested on the forearm but not the palm of the participants. Hair follicle density, however, could not be confirmed as a method to quantify C-tactile mediated affective touch perception or fibre density (paper 3). In the described extended sample of paper 3, the previously suggested and well-known rating patterns of C-tactile mediated affective touch perception were confirmed. Interestingly, a gender-specific difference in the hedonic evaluation of touch could be determined when female participants consistently rated the applied stimuli as significantly more pleasant and erotic than men. Conclusions: The presented articles confirm and extend previous assumptions on the properties and function of C-tactile afferents in humans. At this, C-tactile afferents seem to contribute significantly to the complex concepts of pleasant and erotic touch perception and have an impact on interpersonal behaviour. The results give insights into how gender might modulate C-tactile-mediated touch perception and did not find support for the hypothesis that hair follicle density and C-tactile sensitivity might be related. The Test of Preferred-Velocity however, might be used as a tool to investigate the individually preferred stroking stimulus in further studies.:Abbreviations 1 Figure legend 1 Introduction 2 INTRODUCTION TO THE SOMATOSENSORY SYSTEM: DISCRIMINATIVE AND AFFECTIVE TOUCH 2 C-TACTILE AFFERENTS – PERIPHERAL CHARACTERISTICS OF AFFECTIVE TOUCH 3 SPINAL AND CORTICAL PROCESSING OF C-TACTILE STIMULATION 5 THE “SOCIAL TOUCH HYPOTHESIS” 6 C-TACTILE MEDIATED EROTIC TOUCH PERCEPTION 7 INDIVIDUAL LEVELS OF C-TACTILE SENSITIVITY 9 HAIR FOLLICLE DENSITY AND NERVE FIBER DISTRIBUTION 11 Discussion 14 C-TACTILE AFFERENTS AND EROTIC TOUCH PERCEPTION 14 GENDER DIFFERENCES OF AFFECTIVE TOUCH PERCEPTION 15 STABILITY AND QUANTIFICATION OF AFFECTIVE TOUCH PERCEPTION: INDIVIDUAL PATTERNS OF AFFECTIVE TOUCH AND HAIR FOLLICLE DENSITY 16 LIMITATIONS 19 CONCLUSIONS 21 Zusammenfassung 22 Summary 26 References 29 Publication data 34 Annex I: C-Tactile Mediated Erotic Touch Perception Relates to Sexual Desire and Performance in a Gender-Specific Way. Annex II: The individual preferred velocity of stroking touch as a stable measurement. Annex III: The relation between human hair follicle density and touch perception.
Hintergrund: Zwischenmenschliche Berührung ist ein wichtiger Bestandteil unseres täglichen sozialen Lebens. Sie trägt wesentlich zur Entstehung und Aufrechterhaltung von Beziehungen bei und kann ein sehr kraftvolles, emotionales Kommunikationsmittel sein. In der Interaktion zwischen Eltern und Kind wirkt sich affektive Berührung positiv auf die kognitive und soziale Entwicklung der Heranwachsenden aus und ist im Allgemeinen unter anderem mit einem gesunden Körperbewusstsein und Interozeption verbunden. In den 1990er Jahren konnte eine Gruppe unmyelinisierter Nervenfasern in der behaarten Haut des Menschen identifiziert werden, welche auf die Wahrnehmung solch zwischenmenschlicher, affektiver Berührung spezialisiert sind. Diese sogenannten C-taktilen Nervenfasern werden von langsam streichelnden Berührungen (Geschwindigkeit 1 – 10 cm/s) mit nur leichtem Druck – ähnlich dem sanften Streicheln durch eine menschliche Hand - optimal aktiviert (Löken et al., 2009). Interessanterweise wird diese Stimulierung gleichermaßen in Experimenten als besonders angenehm beschrieben und empfunden. Die Stimuli werden von C-taktilen Nervenfasern mit einer langsamen Leitgeschwindigkeit (ca. 1 m/s) an den somatosensorischen Kortex, aber auch an die Inselrinde des Gehirns weitergeleitet. Letztere trägt unter anderem zu emotionaler Verarbeitung und Integration von Sinneseindrücken bei. Mit diesen Eigenschaften stellen die C-taktilen Nervenfasern einen funktionellen Gegenpol zu den Hauptakteuren der diskriminativen Berührungsempfindung, den Aβ-Fasern, dar. Affektive Berührungswahrnehmung wirkt sich positiv auf die kognitive und soziale Entwicklung von Kindern aus (Field, 2010) und C-taktil vermittelte Berührungswahrnehmung wird in Individuen mit Autismus verändert verarbeitet (Kaiser et al., 2016). Erste Ergebnisse deuten darauf hin, dass C-taktile Nervenfasern weiterhin an der Wahrnehmung erotischer Berührungen beteiligt sind (Jönsson et al., 2015). Vor diesem Hintergrund wird diese Form der taktilen Interaktion auch als „soziale Berührung“ beschrieben, die für die Formung und Aufrechterhaltung zwischenmenschlicher Beziehungen eine wesentliche Bedeutung hat (Olausson et al., 2010). Dabei haben nur wenige Studien bisher die tatsächliche Auswirkung C-taktil vermittelter affektiver Berührungswahrnehmung auf das zwischenmenschliche Verhalten untersucht. Individuen scheinen sich hinsichtlich ihrer peripheren oder zentralen Charakteristika der affektiven Berührungswahrnehmung zu unterscheiden – eine Methode zur Quantifizierung dieser Charakteristika wurde jedoch bisher noch nicht entwickelt. Fragestellung: In den hier vorgestellten Arbeiten wurde zunächst die Beziehung zwischen C-taktil vermittelter Berührungswahrnehmung und sexuellem Verhalten und Verlangen untersucht (Paper 1). In einer zweiten Veröffentlichung wird ein Testverfahren zur Bestimmung der individuell bevorzugten affektiven Berührung vorgestellt. Studien an Nagetieren haben ergeben, dass die den C-taktilen Nervenfasern entsprechenden Mechanorezeptoren um bestimmte Haarfollikel herum angefunden werden (Li et al., 2011). Daraus resultierte die Fragestellung aus Paper 3, einen Zusammenhang zwischen der Haarfollikeldichte am Unterarm und der C-taktil vermittelten Berührungswahrnehmung zu untersuchen. In der Arbeit wird auf dieser Grundlage eine Methode zur Quantifizierung C-taktiler Nervenfasern getestet. Material und Methoden: Paper 1 und 3 präsentieren die Ergebnisse einer psychophysischen Studie an jungen und subjektiv gesunden Probanden, welche an der Medizinischen Fakultät der TU Dresden durchgeführt wurde. In Paper 3 wird diese Studie im Rahmen einer Kooperation mit der Universität Göteborg mit einer dort durchgeführten ähnlichen Studie verglichen und ausgewertet. Die Teilnehmer dieser Studie haben mithilfe eines computer-assistierten Roboters standardisierte dynamische Berührungen mit sowohl C-taktil optimalen als auch suboptimalen Stimuli am Unterarm erhalten. Diese Berührungen wurden hinsichtlich verschiedener hedonischer Aspekte (Angenehmheit, Erotizität) anhand von Visuellen Analog-Skalen bewertet. Sexuelles Verhalten und sexuelles Verlangen wurden mithilfe von Fragebögen ermittelt. Mithilfe der Cyanoacrylate Skin Stripping Methode wurde den Probanden außerdem eine Probe des Stratum corneum der Unterarmhaut entnommen. Anhand dieser Proben wurde lichtmikroskopisch die Haarfollikeldichte pro cm² bestimmt. Die Ergebnisse einer weiteren Studie, welche an der Universität Linköping (Schweden) durchgeführt wurde, werden in Paper 2 aufgearbeitet. In dieser Studie wurde an einer Kohorte von jungen und gesunden Probanden ein Testverfahren (Test of Preferred Velocity) entwickelt und validiert, mithilfe dessen die individuell bevorzugten Berührungs-Stimuli bestimmt werden können. Der Test of Preferred Velocity verwendet ebenso den computer-assistierten Roboter Rotary Tactile Stimulator, mithilfe dessen in einem Forced Choice Paradigma verschiedene Berührungs-Stimuli vergleichend angeboten wurden. Die Studie beinhaltet zwei Teile: Zunächst werden Validierung und Test-Retest-Reliabilität des Testverfahrens beschrieben. Eine Kurzform der Methode wird im zweiten Teil vergleichend an der Handfläche und dem Unterarm von einer neuen Kohorte getestet und validiert. Verschiedene Werte werden für die Einschätzung der individuellen Sensitivität für C-taktil vermittelte affektive Berührung herangezogen: In Paper 1 wird die sogenannte erotic touch differentiation als Differenz zwischen den Erotizitäts-Bewertungen von C-taktil optimalen (1 cm/s) und C-taktil suboptimalen (30 cm/s) Berührungs-Stimuli ermittelt. Die pleasant touch awareness spiegelt einen ähnlichen Wert für die Sensitivität angenehmer Berührungen in Paper 3 wieder, wobei dieser zur durchschnittlichen Höhe der jeweiligen hedonischen Bewertung in Bezug gesetzt wird. Ergebnisse: In der hier vorgestellten Arbeit zeigt sich, dass C-taktil optimale Berührungs-Stimuli mit einer Geschwindigkeit zwischen 1 und 10 cm/s gleichermaßen als angenehm und erotisch empfunden werden. Dies bestätigt die Ergebnisse einer früheren Studie, welche bereits eine Beteiligung C-taktiler Nervenfasern an der Wahrnehmung erotischer Berührungen feststellen konnten (Jönsson et al., 2015). Entsprechend der vorgestellten Hypothesen konnte ein geschlechtsspezifischer Zusammenhang zwischen Werten C-taktil vermittelter erotischer Berührungswahrnehmung und sexuellem Verlangen und Verhalten beschrieben werden (Paper 1): Während unter den Probandinnen ein signifikanter Zusammenhang zwischen der erotic touch differentiation und dem Verlangen nach einer sexuellen Interaktion zu verzeichnen war, konnte in der Gruppe der männlichen Studienteilnehmer ein negativer Zusammenhang zwischen der erotic touch differentiation und der Anzahl tatsächlich stattgefundener sexueller Interaktionen im letzten Monat beobachtet werden. Der Test of Preferred Velocity zeigte sich als geeignet, um individuell bevorzugte Berührungs-Stimuli zu bestimmen und bewies eine hohe Test-Retest-Reliabilität (Paper 2). Mithilfe der hedonischen Bewertung der verwendeten Stimuli konnte der Test weiterhin validiert werden. Die Kurzversion des Testes zeigt ähnlich zuverlässige Eigenschaften und steht bei der Anwendung am Unterarm, nicht jedoch auf der Leistenhaut der Handfläche, mit den hedonischen Bewertungen in Zusammenhang. Die Haarfollikeldichte als Möglichkeit der Quantifizierung C-taktil vermittelter Berührung ließ sich nicht bestätigen (Paper 3). Anhand einer großen Stichprobe können allerdings die bisher bekannten Bewertungsmuster C-taktil vermittelter Berührungen erneut bestätigt werden. Auch hier wird ein geschlechtsspezifischer Unterschied in der hedonischen Bewertung zugunsten der Studienteilnehmerinnen beschrieben. Schlussfolgerungen: Die vorgestellten Arbeiten bestätigen und erweitern bisherige Erkenntnisse zu Eigenschaften und Funktion C-taktiler Nervenfasern im Menschen. C-taktile Nervenfasern scheinen signifikant zu dem komplexen Konzept der Wahrnehmung angenehmer und erotischer Berührungen beizutragen und sich auf das zwischenmenschliche Verhalten auszuwirken. Erstmals werden in diesen Arbeiten auch geschlechtsspezifische Eigenschaften affektiver Berührungswahrnehmung näher. Der vermutete Zusammenhang zwischen Haarfollikeldichte und affektiver Berührungswahrnehmung ließ sich nicht bestätigen. Der Test of Preferred Velocity kann jedoch zur individuellen Quantifizierung der bevorzugten Berührungs-Stimuli in weiteren Studien verwendet und ggf. weiterentwickelt werden.:Abbreviations 1 Figure legend 1 Introduction 2 INTRODUCTION TO THE SOMATOSENSORY SYSTEM: DISCRIMINATIVE AND AFFECTIVE TOUCH 2 C-TACTILE AFFERENTS – PERIPHERAL CHARACTERISTICS OF AFFECTIVE TOUCH 3 SPINAL AND CORTICAL PROCESSING OF C-TACTILE STIMULATION 5 THE “SOCIAL TOUCH HYPOTHESIS” 6 C-TACTILE MEDIATED EROTIC TOUCH PERCEPTION 7 INDIVIDUAL LEVELS OF C-TACTILE SENSITIVITY 9 HAIR FOLLICLE DENSITY AND NERVE FIBER DISTRIBUTION 11 Discussion 14 C-TACTILE AFFERENTS AND EROTIC TOUCH PERCEPTION 14 GENDER DIFFERENCES OF AFFECTIVE TOUCH PERCEPTION 15 STABILITY AND QUANTIFICATION OF AFFECTIVE TOUCH PERCEPTION: INDIVIDUAL PATTERNS OF AFFECTIVE TOUCH AND HAIR FOLLICLE DENSITY 16 LIMITATIONS 19 CONCLUSIONS 21 Zusammenfassung 22 Summary 26 References 29 Publication data 34 Annex I: C-Tactile Mediated Erotic Touch Perception Relates to Sexual Desire and Performance in a Gender-Specific Way. Annex II: The individual preferred velocity of stroking touch as a stable measurement. Annex III: The relation between human hair follicle density and touch perception.

The moment-to-moment fluctuations in pain-evoked sensory and emotional qualities, and how the pain experience differs between sexes are not well understood. Therefore, this thesis sought to 1) characterise the temporal profiles of the most prominent noxious heat-evoked sensations, 2) characterise sex differences in these sensations, 3) evaluate the magnitude of sharp pain quality evoked in hairy and glabrous skin, and 4) determine the role of absolute stimulus temperatures on sex differences in pain adaptation and habituation. A broad-based heat pain model was developed for this study that incorporates a temporally-continuous assessment of multiple sensory and affective pain dimensions, including pain, burning, sharp, stinging, cutting, and annoyance evoked by two types (static, dynamic) of repeated prolonged noxious heat stimuli. The salient hypotheses were: 1) Burning sensations have a different temporal profile compared with sharp and other related qualities, 2) The temporal dynamics of heat pain intensity and annoyance differ between males and females, 3) Sex differences in heat pain are associated with specific pain qualities and specific types of skin, and 4) Moderate-high temperatures induce pain adaptation and habituation in females but not in males. The most prominent findings were 1) sharp, stinging and cutting sensations adapted when stimulus intensity was static, but burning sensations were evoked during static and dynamic stimulus phases, 2) pain and annoyance in women were greater than men during the dynamic phases of the first stimulus but less than men during static stimulus phases and on stimulus repetition, 3) the sex difference in pain adaptation occurred with percept-fixed stimulus intensities and with absolute stimulus temperatures, 4) the sex effects associated with dynamic stimuli occurred in hairy but not glabrous skin. These findings give new insights into the relationships between pain intensity, quality and affect and have strong implications for views on sex differences in pain sensitivity.