Academic literature on the topic 'Trans Epidermal Water Loss'

Mapping facial skin in terms of its biophysical properties plays a fundamental role in many practical applications, including, among others, forensics, medical and beauty treatments, and cosmetic and restorative surgery. In this paper we present an in vivo evaluation of the water content, trans-epidermial water loss and skin thickness in six areas of the human face: cheeks, chin, forehead, lips, neck and nose. The experiments were performed on a population of healthy subjects through innovative sensing devices which enable fast yet accurate evaluations of the above parameters. A statistical analysis was carried out to determine significant differences between the facial areas investigated and clusters of statistically-indistinguishable areas. We found that water content was higher in the cheeks and neck and lower in the lips, whereas trans-epidermal water loss had higher values for the lips and lower ones for the neck. In terms of thickness the dermis exhibited three clusters, which, from thickest to thinnest were: chin and nose, cheek and forehead and lips and neck. The epidermis showed the same three clusters too, but with a different ordering in term of thickness. Finally, the stratum corneum presented two clusters: the thickest, formed by lips and neck, and the thinnest, formed by all the remaining areas. The results of this investigation can provide valuable guidelines for the evaluation of skin moisturisers and other cosmetic products, and can help guide choices in re-constructive/cosmetic surgery.

Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, Universidade de Lisboa, Faculdade de Farmácia, 2017
The human being has the intrinsic desire to improve his appearance. Therefore, hair dyes have become a very popular product, which knows no gender or age barriers. According to statistics, more than 70% of women in developed world admit dyeing their hair at least once in their lifetime and most do so on a regular basis. Due to the extensive use of this type of products and their high chemical complexity, safety and legislation are very important aspects to ensure high standards of safety to consumers. Many users of these cosmetic products are not aware of the short-term and long-term effects they may cause. It is therefore important to study the influence these products can have on the skin, especially in the sensitization or irritation of the skin. This study aimed to study the influence of hair dyes on the epidermal barrier of the skin. The evaluation was performed indirectly using an in vitro model. Changes in the epidermal barrier were monitored through the measurement of TEWL, which is considered a criterion for the evaluation of skin barrier function. The first tests were performed using two controls: water as a negative control and a 20% SDS solution as a positive control. Subsequently, 10 different combinations were tested to evaluate the changes they can produced in the TEWL values, after their application, in relation to the basal values. It can be concluded that all the cosmetic products tested have a deleterious effect on the epidermal barrier of the skin, since all produced an increase in TEWL values. According to the results, there also appear to be no significant differences between the two brands tested and the effects produced on the epidermal barrier. Through this work, it was not possible to confirm the of involvement H2O2 in skin barrier disturbance, nor to relate the percentage and amount of H2O2 present in the formulation and the magnitude of the effects produced. The tests performed were considered insufficient to ascertain the relationship between the compounds tested and the effects produced on the skin, also not allowing elicit associations regarding a particular compound. On the other hand, the tests were performed using pig ear skin, which does not allow extrapolating results obtained for human skin.
O ser humano possui o desejo intrínseco de melhorar a sua aparência. As tintas para o cabelo tornam-se assim um produto cosmético muito popular, que não conhece barreiras de género ou etárias. A utilização de tintas para o cabelo remonta à época dos egípcios, há cerca de 4000 anos, onde as mulheres utilizavam um pó, feito a partir de folhas de henna, para pintar o cabelo, as unhas, ou até partes do corpo. Hoje em dia, podemos optar por pintar o cabelo em casa ou fazê-lo com um profissional num salão de cabeleireiros. Encontramos também ao nosso dispor uma grande variedade de cores, marcas e diferentes formas de colorir os nossos cabelos. Dentro desta categoria, as tintas permanentes possuem a maior quota de mercado, 80%. Existem inúmeras razões para a utilização de tintas para o cabelo, sendo a cobertura dos cabelos brancos apontada como a principal razão. Os aspetos psicológicos da transformação da cor do cabelo, relacionados muitas vezes com uma aparência mais jovem, são o principal impulsionador da utilização destes produtos cosméticos. De acordo com as estatísticas, mais de 70% das mulheres no mundo desenvolvido admitem pintar o seu cabelo pelo menos uma vez na vida e grande parte fá-lo de uma forma regular. Devido à extensa utilização deste tipo de produtos e à sua elevada complexidade química, a segurança e regulamentação são aspetos muito importantes para garantir elevados padrões de segurança para os consumidores. Em todo o mundo, a legislação de produtos cosméticos tem vindo a sofrer inúmeras mudança e a preocupação com os testes realizados em animais encontra-se no topo das prioridades. Na Europa, em 2003, foi publicada a 7ª Alteração à Diretiva de Cosméticos que estabeleceu a proibição de testes realizados em animais para ingredientes e produtos cosméticos acabados, bem como a proibição da sua comercialização. Em 2013, após um período de phasing out, esta lei entrou em vigor. Pelo contrário, na China, estima-se que todos os anos são usados entre 100.000 a 300.000 animais para testar produtos cosméticos. Em 2014, o governo chinês procedeu a algumas alterações e estabeleceu que para cosméticos comuns produzidos no próprio país, os testes em animais deixariam de ser um requisito obrigatório para a sua comercialização. Segundo as estimativas, a China tornar-se-á a maior potência mundial no que respeita ao mercado dos cosméticos, tornando-se preponderante terminar com os testes realizados em animais, sobretudo neste mercado. Muitos utilizadores destes produtos cosméticos não se encontram cientes dos efeitos que estes podem provocar, a curto e a longo prazo. Torna-se assim importante estudar a influência que estes produtos podem ter na pele, especialmente na sensibilização ou irritação da pele. Este trabalho teve como objetivo estudar a influência das tintas para o cabelo na barreira epidérmica da pele. A avaliação realizou-se indiretamente recorrendo a um modelo in vitro. Para a realização destes testes foi utilizada pele de orelha de porco, colocada em células de difusão de Franz. As alterações na barreira epidérmica foram monitorizadas através da medição da perda de água transepidérmica (TEWL), que é considerado um critério para a avaliação da função de barreira da pele. Os primeiros testes foram realizados utilizando dois controlos: a água como controlo negativo e uma solução de SDS com uma concentração de 20% como controlo positivo. Posteriormente, foram testadas 10 combinações diferentes de 8 cremes e quatro reveladores para avaliar a mudança produzida por estes nos valores de TEWL, após a sua aplicação, em relação aos valores basais, previamente medidos. Pode concluir-se que os todos os produtos cosméticos testados têm um efeito nocivo ao nível da barreira epidérmica da pele, uma vez que todos produziram um aumento nos valores de TEWL após a sua aplicação na pele. Segundo os resultados produzidos, parecem também não existir diferenças significativas entre as duas marcas testadas e os efeitos por estas produzidos ao nível da barreira cutânea. Através deste trabalho não foi possível confirmar a participação do H2O2 na perturbação da barreira da pele, nem relacionar a percentagem e a quantidade em que se encontra na formulação e a magnitude dos efeitos produzidos. Os testes realizados foram considerados insuficientes para averiguar a relação entre os compostos testados e os efeitos produzidos ao nível da pele, não permitindo também retirar elações acerca da relação entre um composto em particular e as mudanças verificadas na barreira epidérmica. Por outro lado, os testes foram realizados com recurso a pele de orelha de porco, o que não permite extrapolar os resultados obtidos para a pele humana.

Idris al-Sanusi’s claims to political authority grew in direct relationship to the spread of the colonial state after World War I. One of the primary objectives of negotiations for both parties was the expansion of railway networks in the Cyrenaican interior. Railways symbolized Italy’s arrival as a modern imperial power. For Idris, railways also promised to secure a Sanusi monopoly over trading routes as a source of political authority. The emphasis on railways, however, led to a loss of support from Idris’s political base. Railway construction threatened to undermine the dominance of Sanusi-affiliated tribes over trans-Saharan trade routes based on their access to camels and water supplies. Facing the dissolution of support for his position as a colonial intermediary, Idris al-Sanusi left for self-imposed exile in Egypt in early 1923, months after the rise of a fascist movement in Italy that embraced a virulent form of nationalist expansion.

AbstractIn order to assess new and often costly treatments, the need for objective scar measurement tools has become increasingly important. A combination of subjective and objective measures should be the aim of every researcher. Quantitative assessment of scars requires devices to measure their physical and physiological properties. Physiological scar parameters are scar characteristics relevant to pathological scarring which cannot be seen with the bare eye. This also means that they can only be assessed with objective assessment tools.Skin hydration is defined as the water content of the epidermis and the dermis, and the ability of the skin to retain water is important to avoid dry appearance of the skin and prolonged inflammation in scarring. Many approaches exist to measure skin water content. One single method is often not enough to capture all the relevant information. Trans-epidermal water loss, stratum corneum water content, and dermal water content are equally important and related to each other.Scar maturation has been related to transcutaneous oxygen tension, and it is hypothesized that low levels of transcutaneous oxygen pressure in evolving scars result from low oxygen diffusibility through scar tissue.Tactile sensitivity of the skin can be measured by esthesiometers. The Semmes-Weinstein monofilament test is found to be a feasible and reliable outcome measure to evaluate touch perception threshold in older upper extremities burn scars.

At present, power cycles used in HTGR are indirect steam Rankine cycle and helium Brayton cycle. Using water or helium as working fluid which transform thermal energy into mechanical energy for HTGR power cycle has many disadvantages. Steam cycle could choose steam system which is similar to conventional coal-fired power plant, but because of the limit of material and equipments, there is big temperature difference between the steam and the helium, that makes big loss of thermal power and lowers the cycle efficiency. Helium can reach a high temperature in HTGR Brayton cycle and it has good stability, but because of helium has big isentropic exponent and low density, it is difficult to compress and makes helium turbine has shorter blades and more stages than normal gas turbine. Carbon dioxide has good thermal stability and physical properties. To avoid the reaction of CO2 with graphite and canning of fuel element at high temperature, it should be used in an indirect cycle as second loop working fluid. CO2 has appropriate critical pressure and temperature (7.38MPa, 304.19K) and can choose three types of cycle: supercritical cycle, subcritical-pressure cycle and trans-critical-pressure cycle (CO2 sometimes works under supercritical pressure, some times under subcritical-pressure). Carbon dioxide cycle works in a high pressure, so it makes pressure loss lower. When CO2 works close to its critical point, its density become larger than other conditions, and not change very much, this permits to reduce compress work. The thermal physical properties of carbon dioxide are totally different from helium due to CO2 works as real gas in the cycle. That causes the calculation of CO2 thermal physical properties, heat transfer and power cycle efficiency become difficult and need to be iterated. A systematic comparison between helium and carbon dioxide as working fluid for HTGR has been carried out. An empirical equation had been selected to estimate the thermal physical properties of carbon dioxide. Three types of carbon dioxide power cycle have been analyzed and the thermal efficiency has been calculated. A detailed introduction to the basic calculation process of the CO2 cycle thermal efficiency had been presented in the paper.