Aim: To examine the reaction of extreme preterm infants with regarding to body temperature and transepidermal water loss during skin-to-skin care according to Kangaroo Mother Care (KMC) during the infant’s first week of life. Method: This was a descriptive quantitatively designed study, which was a pilot study within the framework of a larger project. Nine children, with a median gestational age of 24.91 weeks, were examined by measuring body temperature (axilla and skin temperature) as well as transepidermal water loss before, during and after KMC. Results: The study showed that skin temperature tended to rise during KMC, especially for those children who were nursed with KMC for more than 60 minutes. Eight out of nine children had, after completing KMC, a normal axilla temperature. As was expected, transepidermal water loss was elevated when measured both pre and post test. Despite this, the children showed normal body temperature. Conclusion: The results of the study support that KMC can create a micro-climate that, for at least one hour, makes it possible for even extreme preterm infants to maintain a body temperature within the normal range during their first week of life.

The aim of this study was to investigate the reproductive ecology including fecundity, reproductive season, timing of larval release, evaporative water loss during reproductive migration, and the salinity tolerance of first zoeal stage of Cardisoma carnifex in Houwan, Hengchun Peninsula. The average carapace width of ovigerous females was 70.5 ¡Ó 6.57 mm, with a size range of 56.0-93.7 mm. Fecundity intimates increased with size and the number of hatched larvae from individual female varied from 90,000 to 490,000. The reproductive season of C. carnifex began at the onset of the rainy season and ends approximately at the end of that season. The reproductive season was from June to Oct. in 2009 and May to Sept. in 2010. The peaks of larval release occurred in July in 2009, 2010. Some females had the capacity in spawning twice during a reproductive season. Ovigerous females releasing larvae synchronously. The relationship between larval release timing and environmental cycle is listed in decreasing order of importance: diel rhythm, semilunar rhythm, tidal amplitude rhythm, and a low correlation was found with the tidal rhythm. Ovigerous females of C. carnifex started to release larvae after the new and full moon, lasting for 6-8 days with peaks occurring 4-6 days after the new and full moon. The peaks of larval release occurred within 2-3 hours after the sunset time (i.e., between 1930H and 2130H). This species exhibits different larval release timing and behavior compare to other species of Gecarcinidae; ovigerous females of gecarcinid crabs follow a lunar rhythm but C. carnifex follow a semilunar rhythm. More than half of the ovigerous females stayed in the water for up to 10 min (average 5.5 ¡Ó 2.87 min) and could move to deep water (i.e., 120 cm) to release their larvae. A few females even released their larvae in the freshwater environment. For C. carnifex, a mean of 15¢H of its original weight was lost by the time they died and the osmolality of the hemolymph is 856 mOsm kg-1. Compare with the hemolymph osmolality of ovigerous females (694 ¡Ó 6.3 mOsm kg-1), the results indicated that the ovigerous females at Houwan may not experience severe water loss during larval release migration. The first zoeal stage of C. carnifex could not survive in the freshwater, all larvae died within 2 hours. However, at salinities large than 5‰, most larvae could survive for more than 3 days. The results show first zoeal stage of C. carnifex had adapted to the low salinity in the estuary.

Le flétrissement bactérien causé par Ralstonia solanacearum limite la production mondiale de nombreuses cultures. La diversité génétique étendue de la bactérie a permis au cours des dernières années de concevoir le concept de complexe d'espèces de R. solanacearum (RSSC). Le séquençage génomique de plus de 30 souches représentatives de chaque groupe phylogénétique a élargi notre connaissance de l'évolution et de la spéciation du RSSC. Cela a permis d'identifier de nouvelles fonctions associées à la virulence. En outre, un grand nombre d'études ont été réalisées sur l'interaction plantes hôtes-R. solanacearum et éclairent la génétique, la biologie moléculaire et le développement de la maladie. Ces études ont documenté les stratégies d'infection qu'utilise R. solanacearum pour faire face aux défenses immunitaires des plantes. Bien que ces données qualitatives soient fondamentales pour comprendre l'infection par R. solanacearum, elles sont insuffisantes pour savoir si une plante sera infectées ou non. Cette question fondamentale nécessiteune compréhension quantitative des processus responsables de l'infection et colonisation de la plante par la populations de R. solanacearum. Ce travail a permis une étude quantitative permettant de répondre à la question suivante:"Combien d'individus de R. solanacearum entrent de la racine pour établir la base de l'infection donnant lieu a la maladie bactérienne dans la plante?" Cela nous a permis de déterminer quels facteurs contrôlent cette dynamique d'infection de R. solanacearum au sein de la plante hôte. Cette question scientifique nécessite un réexamen du cycle de vie de R. solanacearum et la caractérisation précise de l'ensemble du processus d'infection dans la plante. Sept paramètres dynamiques ont été affinés à partir de cinq étapes d'infection de R. solanacearum. Ensuite, nous avons établi un modèle mathématique de la dynamique dans l'hôte de la bactérie par l'intégration de ces paramètres. Le modèle suggère que toute la dynamique de la population influe sur la taille de la population de R. solanacearum. L'évaluation in vivo des paramètres et de leurs interactions prédit une petite taille de la population fondatrice, autour de quatre centaines de celluels bactériennes, ce qui a été confirmé par des mesures expérimentales avec une approche probabiliste. Pour comprendre les mécanismes qui restreignent la population de R. solanacearum, nous avons étudié les impacts de la virulence bactérienne, des barrières des plantes et du facteur environnemental sur la population fondatrice de l'infection. Nous avons montré que le goulot d'étranglement des infections est principalement modulé par l'agent pathogène (arsenal de virulence), l'hôte (caractéristiques physiques et immunitaires) et les conditions environnementales (température) en accord avec des études qualitatives. / Bacterial wilt caused by Ralstonia solanacearum limits the global production of many crops. The extensive genetic diversity of the bacterium has in recent years led to the concept of a R. solanacearum Species Complex (RSSC). Genome sequencing of over 30 representative strains of the each phylogenetic groups has broadened our knowledge of the evolution and speciation of RSSC. This enabled the identification of novel virulence-associated functions. Furthermore, a large number of studies have been carried on plants-R. solanacearum interactions and shed light on the genetics, molecular biology, and disease development. These studies have documented the infection strategies of R. solanacearum employed to cope with plant immune defenses. Although these qualitative investigations are a basis to understand the pathogenesis of R. solanacearum, they are insufficient to know whether or not plants will be diseased. These fundamental questions require a quantitative understanding of the processes responsible for the rise, dissemination and fall of the infection populations of R. solanacearum. This work pioneered the quantitative study in plant bacterial pathogens by addressing the following question: "How many R. solanacearum individuals enter from the root to establish the bacterial wilt disease in plant?" It allowed us to determine what factors control the infection dynamics of R. solanacearum within the host plant. This scientific question requires a re-examination on the life cycle of R. solanacearum and the precise characterization of the whole infection process in plant. Seven dynamical parameters were refined from five subsequent infection steps of R. solanacearum in host plant. Then, we established a mathematical model of within-host dynamics of the bacterium by the integration of these parameters. The model suggests that the whole population dynamics influences the founding population/bottleneck size of R. solanacearum. The in vivo assessment of parameters and their interactions predicted a small founding population size, around four hundred bacterial cells, which was confirmed by experimental measurements with a probabilistic approach. To understand mechanisms restricting R. solanacearum population, we further investigated impacts of bacterial virulence, plant barriers and environmental factor on the infection founding population. We showed that infection bottleneck is mainly modulated by the pathogen (virulence arsenal), the host (physical and immunity traits) and the environmental conditions (temperature).

O presente trabalho aborda os conceitos que envolvem as perdas no sistema de distribuição de água e os diferentes indicadores de perdas existentes, utilizados como um dos principais instrumentos de apoio à gestão nos sistemas de abastecimentos de água. A revisão bibliográfica apresenta histórico dos trabalhos referentes ao controle e redução de perdas que tem sido desenvolvidos no Brasil e em outros países. Mostra a diversidade de indicadores de perdas existentes e os estudos e discussões incessantes na busca de sua padronização, coordenados pela International Water Association (IWA). Também trata de importantes questões relativas ao tema da dissertação, tais como: a elaboração do Balanço Hídrico e os limites de incertezas de suas variáveis; e as iniciativas existentes ao redor do mundo relacionadas ao uso eficiente de energia e sua interface entre a redução de perdas em sistemas de abastecimento de água. Na segunda etapa do trabalho, foram elaborados passo a passo os Balanços Hídricos de três setores de abastecimento da Região Metropolitana de São Paulo (RMSP) com características distintas entre si. Em razão da dificuldade de medições de alguns volumes de entrada dos Balanços Hídricos, recorreu-se à alternativa de calculá-los através de estimativas, cujos valores padrões foram pesquisados na bibliografia existente. Devido a isso, os fluxos dos Balanços Hídricos estudados apresentaram faixas de valores, retratando os limites de incertezas a que eles estão submetidos. Compararam-se os Balanços Hídricos dos três setores de abastecimento, avaliando-se suas incertezas, analisando-se seus resultados e recomendando-se onde podem ser direcionadas as ações para o controle e redução, sejam para as perdas reais, sejam para as perdas aparentes. Por fim, ressalta-se que por se tratar de tema correlacionado às dissertações desenvolvidas por Galvão (2007), Melato (2010), Oliveira (2011) e Palo (2010), este estudo serve, portanto, como uma continuidade desses trabalhos. / This project has the purpose of treat the conceptions involving losses in water distribution systems and different performance indicators, used as a major instrument of management support systems in water supplies. Bibliographic review presents a historic of the works on the control and reduction of water losses that have been developed in Brazil and other countries. It shows the diversity of existing indicators of water losses and incessant studies and discussions in the search for its standardization, coordinated by the International Water Association (IWA). It also deals with important issues related to the subject of the dissertation, such as the elaboration of the water balance and the limits of uncertainty of its variables, and the existing initiatives around the world related to the energy efficiency and its interface with the reduction of losses in water supply systems. In the second stage of the work, the Water Balances of three different supply sectors of the Metropolitan Region of São Paulo were developed step by step. Because of the difficulty of measurements of some volumes of incoming Water Balance, one resorted to the alternative of calculating them through estimates, whose default values were researched in existing literature. Due to this, the flow of Water Balance study showed ranges of values, depicting the limits of uncertainty to which they are submitted. The Water Balance of three supply sectors were compared, evaluating their uncertainties, analyzing their results and recommending where actions should be directed to the control and reduction whether they are real or apparent losses. It is important to say that since it is correlated themes to dissertations developed by Galvão (2007), Melato (2010), Oliveira (2011) and Palo (2010), will represent, therefore, as continuity to their works.

O polietileno surgiu em 1898 e logo já começou a ser utilizado como conduíte e isolante. Desde então este material vem ganhando muito espaço no mercado de tubulações, seja no saneamento, mineração, indústrias ou no segmento de petróleo e gás. Seu tipo mais usado é o Polietileno de Alta Densidade (PEAD), que apesar de já ser comumente encontrado em adutoras, emissários e ramais prediais, somente nos últimos anos passou a ser utilizado de maneira mais abrangente nas redes de distribuição de água, se tornando um aliado importante no combate aos altos índices de perdas reais. No Brasil, somente nos últimos anos que a presença de tubulações de PEAD em redes de distribuição de água potável se tornou mais comum. Contudo, é possível identificar cenários de aplicação do PEAD em sistemas de abastecimento de água já relativamente consolidados, como é o caso do Departamento Municipal de Água e Esgotos (DMAE) de Porto Alegre, que utiliza o material há 25 anos, a Companhia de Saneamento Básico do Estado de São Paulo (Sabesp), onde desde 2009 a Diretoria Metropolitana vem utilizando o PEAD em novas aplicações em redes e a Odebrecht Ambiental da cidade de Limeira, que utiliza tubos deste material desde 2007. Através de análises de custos de implantação, operação e manutenção, de amostragens da condição de tubulações em operação, da evolução de índice de perdas e de entrevistas com as equipes de operação e planejamento, é possível verificar que realmente as tubulações de PEAD auxiliam no combate às perdas reais e na otimização da operação e eficiência das prestadoras de serviços de distribuição de água potável, no sentido de diminuir o tempo de intervenção de redes, os custos de manutenção e a frequência de arrebentamento e vazamentos nas redes de abastecimento. / Polyethylene appeared in 1898 and soon started been used as conduit and insulating material. Since then, the material has been gaining a lot of space in the pipes market in sanitation, mining, industries and oil & gas production. The most used type is High Density Polyethylene (HDPE), which despite being commonly found in water mains, emissaries and communication pipes, only in recent years began to be used more widely in water distribution networks, becoming an important ally in the fight against high rates of real water losses. In Brazil, only in recent years the use of HDPE pipes has become more common in public water distribution networks. However, it is possible to identify HDPE application cases in relatively consolidated water supply distribution networks, such as the Departamento Municipal de Água e Esgotos (DMAE) of Porto Alegre, which have used the material for 25 years; the Companhia de Saneamento Básico do Estado de São Paulo (Sabesp), where since 2009 the Metropolitan Unit has been using HDPE in new applications in network pipes and Odebrecht Ambiental, in Limeira city, which uses this material in water pipelines since 2007. Through research of implementation, operation and maintenance costs, sampling the condition of pipes in operation, analysis the real losses indicators and interviews with the operations and planning teams, it is possible to conclude HDPE pipes contribute to reduction of real losses and optimization of the operation and efficiency of the providers of drinking water distribution services, decreasing maintenance time and costs.

O presente trabalho investiga o efeito da redução de pressão em rede de distribuição de água, provocada pela instalação de válvulas redutoras de pressão (VPRs), no consumo médio total medido em ligações de água, localizadas em áreas sob influência daquele equipamento. Foi feito um levantamento no estado da arte em gestão de sistemas de abastecimento de água, com ênfase no controle de perdas, focado na gestão de pressão. Para se avaliar a possível redução de consumo, foi desenvolvida uma metodologia estatística, baseada em critérios de filtragem de dados de amostra e em testes paramétricos de hipóteses. O estudo de caso foi feito na Região Metropolitana de São Paulo (RMSP), utilizando sistema de informações geográficas (SIG), que permitiu o relacionamento de limites geográficos, com informações de consumo, através da integração com um sistema de informações comerciais, onde foi possível a obtenção de dados de consumos individuais, de ligações de água. Foram comparados os consumos, antes e depois da implementação de VRPs, com a correspondente redução de pressão, em áreas controladas por VRP e em áreas testemunha (sem influência da redução de pressão), através da realização de testes paramétricos de hipóteses. Foram, ainda, comparadas a variação no consumo médio das áreas de VRP, com a variação no consumo médio das áreas testemunha. Os resultados obtidos indicam que, embora tenha ocorrido uma tendência de redução no consumo de algumas áreas pesquisadas, esta redução não pode ser atribuída à implementação das VRPs. / The following study investigates reduction in average costumers\' consumption due to pressure reduction in water distribution systems, trough installation of pressure reducing valves (PRVs). A research on the state of art on water distributions systems management techniques was carried out, emphasizing water-loss control aspects, with focus on pressure management techniques. A statistical methodology based upon data filtering criteria and on statistical tests of hypothesis was developed to assess a possible effect in the water consumption reduction, for sample areas water consumption data. A case study was carried out in the Metropolitan Region of Sao Paulo (MRSP) using a Geographic Information System (GIS). Relationship between the geographical study areas limits and the costumers\' water consumption information was made by through use of GIS tools. Information on individual customers\' water connections were retrieved from a commercial information data base system. Comparisons between average water consumption before and after PRVs initial operation were carried out. Same comparisons were applied in testimony areas (water distribution areas not submitted to water pressure reduction), in similar conditions to PRVs controlled areas. These comparisons were verified trough statistical parametric tests of hypothesis. The results showed that, despite of a tendency of lowering average water consumption in some of the researched areas it was not confirmed the influence of water pressure reduction on it.

As perdas de água em sistemas de abastecimento apresentam-se como um dos maiores desafios das operadoras de água em todo o mundo. Nos últimos 12 anos os níveis de perda de água na distribuição no Brasil têm se mantido próximo à 40%, valor bem superior quando comparado a outras regiões do globo. Frente ao atual cenário de crise hídrica e aumento da demanda da água, as ações de controle de perdas requerem atenção. No cenário nacional, as bacias hidrográficas dos rios Piracicaba Capivari e Jundiaí destacam-se pelo empenho dos Comitês PCJ que têm atuado junto aos municípios para controlar os níveis de perdas da área. A crítica situação da disponibilidade hídrica nas bacias, o potencial de redução da pressão sobre os recursos hídricos e o ganho econômico se os níveis de perdas forem reduzidos reforçam a premência na adoção de práticas de controle de perdas eficientes. Nesta perspectiva, a presente pesquisa buscou identificar, no contexto das operadoras das bacias PCJ, quais práticas de controle de perdas de água na distribuição estão associadas ao desempenho considerado superior no controle, calculando o nível de perdas de água dos municípios e explorando quais práticas de controle são empregadas pelas operadoras. A primeira etapa metodológica correspondeu a aplicação da técnica de benchmarking junto as operadoras em estudo para avaliar o desempenho das mesmas no controle de perdas, incluindo a seleção de indicador, formulação de questionário de dados operacionais, coleta de dados online, análise da credibilidade dos dados e cálculo do nível de perdas de água de cada município com o ranqueamento dos mesmos. A segunda etapa foi direcionada ao levantamento e análise das práticas de controle de perdas empregadas pelas operadoras das bacias, mediante a aplicação in loco do questionário de práticas, elaborado a partir de revisão bibliográfica. Na terceira etapa, utilizando ferramentas estatísticas, as práticas de controle analisadas foram cruzadas com as categorias de desempenho, superior e inferior, identificando quais práticas de controle estão associadas as classes de desempenhos. A amostra final de municípios analisados incluiu 41, dos 70 membros dos Comitês, cujos dados se enquadraram nos níveis de credibilidade estabelecidos para fins de comparação de desempenho. A aplicação do benchmarking possibilitou analisar os desempenhos das operadoras que atuam na área, comparando os níveis de perdas de água e identificando quais municípios necessitam de urgência atenção em ações de controle. Testes de comparação de média, conduzidos com o produto do benchmarking evidenciaram que há diferenças significativas nos níveis de perdas de água quando considerado o porte do município, natureza jurídica da operadora e presença de favelas. A análise das práticas de controle empregadas apontou o empenho das operadoras da área em controlar as perdas de água, concentrando ações em trocas de rede, setorização e macromedição, sendo verificada diferenças significativas no índice médio de perdas quando uma prática é ou não aplicada. A análise de associação e correspondência indicaram que 24 práticas estão associadas e impactam os níveis de perdas de água. Salvo este aspecto, é imprescindível reforçar a importância do mix de práticas na obtenção de resultados mais eficientes e satisfatórios. Com caráter exploratório, as assertivas desse estudo podem nortear as ações de controle de outras operadoras sendo fundamentais estudos de custo benefício para definir quais práticas produzirão resultados de redução mais efetivos. / The water loss in supply system have presented as one of the biggest challenges of water companies around the world. In the last 12 years the water loss levels in Brazilians distribution systems have remained close to 40%, level higher than other areas in the globe. Face of the water crisis and increasing water demand, the actions to control the water loss require attention. In the national context, the Piracicaba, Capivari and Jundiai river basins have focus by the Committees efforts that have been acting along with the cities to control the water loss levels in the area. The critical situation of water availability in the river basins, the reduction potential on hydric resources and the financial gain, if the water loss levels have lowered, enhance the urgency to adopt efficient control practices of water loss. Accordingly, the present research has searched to identify, in the context of PCJ river basins water companies, which water loss control practices are associated with the higher performance, measuring the citys water loss levels and exploiting which control practices have applied by the water companies. The first methodological step was the application of the benchmarking technique to measure the performance in water loss control, including indicator choice, questionnaire formulation of operational data, online data collection, data reliability analysis and determination of cities water loss levels, with ranking of this. The second step had directed to the gathering and analysis of control practices adopted by the companies in the area, by applying the practices questionnaire, elaborated as of bibliographic review, in loco. In the third step, using statistic tools, the control practices had crossed with the performance in water loss control, higher and lower, identifying which practices have associated with the companies performance. The final sample analyzed included 41 cities, of the 70 PCJ Committees members, that data had fit in the reliability levels established for performance comparison purposes. The benchmarking application had enabled to analyze the companies\' performance comparing the water loss levels and identifying which cities need urgent attention in control practices. Testes of means comparison had emphasized that there are significant differences in the water loss levels when deemed the city size, company\'s legal nature and presence of slumbs. The control practices analysis had indicated the company\'s efforts to control the water loss, focusing in network exchange, district meters\' areas, macromediation system, been checked significant differences in the water loss average index when a practice is adopting or not. The association and correspondence analysis had indicated that 24 practices area associated and affect the water loss levels. Barring this aspect, is essential to strengthen the importance of control practices mix to achieve efficient and satisfactory results. With an exploratory profile, the results of this research can guide the control actions of others companies, been essential cost-benefit studies to establish which practices will generate reduction results more effectives.

This thesis deals with efficiency of colostrum contained in cosmetics. The aim of study was to determine whether the colostrum contained in cosmetic preparations have any influence on the state of human skin. The theoretical part is a literary review and it deals with defining the basic concepts and phenomena, especially the colostrum, its composition and properties. There is also discussed the raw materials used for real samples preparation and efficiency evaluated on these samples. There are also described the methods used to evaluate cosmetic products. The practical part is focused on evaluating the influence of hydratation of prepared cosmetic products. The skin hydratation and transepidermal water loss was measured by MPA 5. Consumer tests are attached to this part. Chemical stability of these cosmetics is assessed in a special chapter.

4 Summary Seasonal metabolic adjustments and partitioning of evaporative water loss in Wahlberg’s epauletted fruit bat, Epomophorus wahlbergi Student: Ingrid A. Minnaar Supervisor: Prof. A. E. McKechnie Co-supervisors: Prof. N. C. Bennett, Prof. Christian T. Chimimba Department: Zoology and Entomology, University of Pretoria Degree: MSc: Zoology The capacity to thermoregulate over a wide range of TaS is critical for maintaining homeostasis in endotherms. Several aspects of the thermoregulatory properties of bats remain poorly studied when compared to other mammals and birds. I examined two specific aspects of thermoregulation in bats: the seasonal variation of maximum metabolic heat production and the partitioning of total evaporative water loss (TEWL) into respiratory and cutaneous components. I measured basal metabolic rate (BMR) and summit metabolism (Msum) in captive and wild Wahlberg’s epauletted fruit bats, Epomophorus wahlbergi, during summer and winter. I measured metabolic rate using flow-through respirometry, and elicited Msum by exposing bats to low temperatures in a helox (21% O2, 79% He) atmosphere. BMR decreased by 22-25% during winter in both captive and wild bats, with the BMR of captive bats 9-13% lower than the wild individuals across seasons. Msum was approximately seasonally stable in both captive and wild bats, but Msum in captive individuals was 13-18% higher than their wild conspecifics during both seasons. The ratio between Msum and BMR (i.e., metabolic expansibility) was greater in winter than during summer for both captive and wild bats. One likely explanation for the greater resting thermogenic capacity of the bats in captive individuals concerns their reduced activity levels; compared to wild, free-ranging bats, heat produced as a by-product of activity probably contributed far less to thermoregulation, apparently leading to an increase in resting heat production capacity in captive individuals. 5 At the other end of the thermal scale, knowledge of heat tolerance and the evaporative cooling mechanisms employed by bats in hot weather remains rudimentary. At high air temperatures (Ta), endotherms avoid overheating by dissipating heat via evaporative water loss. TEWL may be partitioned into cutaneous evaporative water loss (CEWL) and respiratory evaporative water loss (REWL). I quantified CEWL and REWL in E. wahlbergi at Tas of 10-40 °C using a latex mask. When Ta exceeded normothermic Tb, bats drastically increased their TEWL, metabolic rate and Tb. The relative contribution of CEWL to TEWL was the greatest at moderate Tas where it represented up to 80% of TEWL. REWL was the major route of evaporative cooling at the highest Ta: at Ta = 40 ºC, REWL represented 45% of TEWL. To avoid hyperthermia, E. wahlbergi greatly increased metabolic rate at high TaS to avoid hyperthermia, further compounding the need to cool down. REWL is thought to be less efficient as than CEWL in offloading heat at high TaS as panting increases metabolic heat, whereas CEWL occurs passively. There is a need for further studies to be conducted on the thermoregulatory capabilities of bats in varying environmental conditions, both intra- and interspecifically. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Zoology and Entomology / unrestricted

The aim of this diploma thesis was to summarize the basic knowledge of human skin and it's biophysical parameters. Attention was focused on influence of cosmetic products with different pH on the change of skin parameters especially. The first part describes the anatomical and histological structure of the skin, it's basic functions and development. In the following chapters of this work is mentioned physiological representation of microorganisms found on the skin surface and general characteristics of cosmetic products. There are used in everyday skin care that affect the natural skin surface pH value. Optimum surface pH is important for the proper functioning of human skin. The final chapters of the described the characteristics of the basic biophysical parameters of the skin (hydration, TEWL, pH, sebum) and methods for their measurement. Key words: skin, transepidermal water loss, pH, hydration, sebum, microbiome