Diversity of pigmentation in cultured human melanocytes is due to differences in the type as well as quantity of melanin

Cultured human melanocytes differ tremendously in visual pigmentation, and recapitulate the pigmentary phenotype of the donor's skin. This diversity arises from variation in type as well as quantity of melanin produced. Here, we measured contents of eumelanin (EM) and pheomelanin (PM) in 60 primary human melanocyte cultures (51 neonatal and nine adults), and correlated some of these values with the respective activity and protein levels of tyrosinase, and the melanocortin-1 receptor (MC1R) genotype. Melanocytes were classified into four phenotypes (L, L+, D, D+) as depicted by visual pigmentation using light microscopy, and by the pigmentary phenotype of the donor's skin. There were large differences in total melanin (TM) and EM, which increased progressively for L, L+, D and D+ melanocytes. TM content, the sum of EM and PM, showed a good correlation with TM measured spectrophotometrically, and with the activity and protein levels of tyrosinase. Log EM/PM ratio did not correlate with MC1R genotype. We conclude that: (i) EM consistently correlates with the visual phenotype; (ii) lighter melanocytes tend to be more pheomelanic in composition than darker melanocytes; (iii) in adult melanocyte cultures, EM correlates with the ethnic background of the donors (African-American > Indian > Caucasian); and (iv) MC1R loss-of-function mutations do not necessarily alter the phenotype of cultured melanocytes.

Eyewitness memory: Balancing the accuracy, precision, and quantity of information through metacognitive monitoring and control

Historically, memory has been evaluated by examining how much is remembered, however a more recent conception of memory focuses on the accuracy of memories. When using this accuracy-oriented conception of memory, unlike with the quantity-oriented approach, memory does not always deteriorate over time. A possible explanation for this seemingly surprising finding lies in the metacognitive processes of monitoring and control. Use of these processes allows people to withhold responses of which they are unsure, or to adjust the precision of responses to a level that is broad enough to be correct. The ability to accurately report memories has implications for investigators who interview witnesses to crimes, and those who evaluate witness testimony. ^ This research examined the amount of information provided, accuracy, and precision of responses provided during immediate and delayed interviews about a videotaped mock crime. The interview format was manipulated such that a single free narrative response was elicited, or a series of either yes/no or cued questions were asked. Instructions provided by the interviewer indicated to the participants that they should either stress being informative, or being accurate. The interviews were then transcribed and scored. ^ Results indicate that accuracy rates remained stable and high after a one week delay. Compared to those interviewed immediately, after a delay participants provided less information and responses that were less precise. Participants in the free narrative condition were the most accurate. Participants in the cued questions condition provided the most precise responses. Participants in the yes/no questions condition were most likely to say “I don’t know”. The results indicate that people are able to monitor their memories and modify their reports to maintain high accuracy. When control over precision was not possible, such as in the yes/no condition, people said “I don’t know” to maintain accuracy. However when withholding responses and adjusting precision were both possible, people utilized both methods. It seems that concerns that memories reported after a long retention interval might be inaccurate are unfounded. ^

The Impact of Workshops on the Quality and Quantity of Parent-Child Booksharing Skills

A pilot study posits that conducting a number of literacy workshops with teenage mothers translated into a greater number of appropriate booksharing skills implemented while reading to the child. The results of one- and two-way ANOVAs and of a contingency table with crosstabs are included.

Eyewitness Memory: Balancing the Accuracy, Precision, and Quantity of Information through Metacognitive Monitoring and Control

Historically, memory has been evaluated by examining how much is remembered, however a more recent conception of memory focuses on the accuracy of memories. When using this accuracy-oriented conception of memory, unlike with the quantity-oriented approach, memory does not always deteriorate over time. A possible explanation for this seemingly surprising finding lies in the metacognitive processes of monitoring and control. Use of these processes allows people to withhold responses of which they are unsure, or to adjust the precision of responses to a level that is broad enough to be correct. The ability to accurately report memories has implications for investigators who interview witnesses to crimes, and those who evaluate witness testimony. This research examined the amount of information provided, accuracy, and precision of responses provided during immediate and delayed interviews about a videotaped mock crime. The interview format was manipulated such that a single free narrative response was elicited, or a series of either yes/no or cued questions were asked. Instructions provided by the interviewer indicated to the participants that they should either stress being informative, or being accurate. The interviews were then transcribed and scored. Results indicate that accuracy rates remained stable and high after a one week delay. Compared to those interviewed immediately, after a delay participants provided less information and responses that were less precise. Participants in the free narrative condition were the most accurate. Participants in the cued questions condition provided the most precise responses. Participants in the yes/no questions condition were most likely to say “I don’t know”. The results indicate that people are able to monitor their memories and modify their reports to maintain high accuracy. When control over precision was not possible, such as in the yes/no condition, people said “I don’t know” to maintain accuracy. However when withholding responses and adjusting precision were both possible, people utilized both methods. It seems that concerns that memories reported after a long retention interval might be inaccurate are unfounded.

Minimum Vital of Drinking Water in the Jurisprudence of the Colombian Constitutional Court

The minimum vital of drinking water for vulnerable people isprotected by the Colombian Constitutional Jurisprudence,locally and nationally. The Constitutional Court has created asolid jurisprudential line on the right to water in relation to thesuspension of water supply service for the customer’s failure topay for the service; this Court has also defined the conditionsnecessary for the companies to refrain from suspending serviceand the minimum amount necessary for survival. Compliance withthese sentences has been limited to the orders pronounced to thebenefit of the company that provides such service, including theexecution of payment agreements for accessing the water supply.The implementation of the free minimum vital of drinking water inColombia has been defined through targeting and requirements thatare set only to benefit market laws, such as payment agreements,except for Bogota that, from the point of view of human rights,has proposed the respect for the minimum vital of drinking waterfor all social strata.

The minimum number of measurements for colour, sparkle, and graininess characterisation in gonio-apparent panels

Materials with new visual appearances have emerged over the last few years. In the automotive industry in particular there is a growing interest in materials with new effect finishes, such as metallic, pearlescent, sparkle, and graininess effects. Typically, for solid colours the mean of three measurements with repetitions is sufficient to obtain a representative measurement for colour characterisation. However, gonio-apparent panels have non-homogeneous colours, and there are no studies that recommend the minimum number of repetitions for colour, sparkle, and graininess characterisation of this type of panel. We assume that colour panels incorporating special-effect pigments in their colour recipes will require a higher minimum number of measurements than solid colour panels. Therefore, the purpose of this study is to verify this assumption by using a multiangle BYK-mac spectrophotometer, given that it is currently the only commercial device that can measure colour, sparkle, and graininess values simultaneously. In addition, a possible methodology is given for establishing the minimum number of measurements when characterising gonio-apparent materials using a specific instrument, able to be implemented in future instruments when determining multiple appearance attributes (colour, gloss, sparkle, etc.) for many coloration technologies. Thus, we studied the minimum number of measurements needed to characterise the colour, sparkle, and graininess of three types of sample with solid, metallic, and pearlescent coatings respectively. Twenty measurements were made at twenty random positions (different target areas) of 90 samples. The minimum number of measurements for all these variables was determined on the basis of the point at which the cumulative mean value became constant. Thus, applying new statistical tools, it is clearly shown that metallic and pearlescent panels require more colour measurements than solid panels, in particular when geometries are being measured in a specular direction. As regards texture (sparkle and graininess), more measurements are needed for graininess than for sparkle, and more for metallic panels than for pearlescent panels.

An algorithm for finding the minimum cost of storing and regenerating datasets in multiple clouds

The proliferation of cloud computing allows users to flexibly store, re-compute or transfer large generated datasets with multiple cloud service providers. However, due to the pay-As-you-go model, the total cost of using cloud services depends on the consumption of storage, computation and bandwidth resources which are three key factors for the cost of IaaS-based cloud resources. In order to reduce the total cost for data, given cloud service providers with different pricing models on their resources, users can flexibly choose a cloud service to store a generated dataset, or delete it and choose a cloud service to regenerate it whenever reused. However, finding the minimum cost is a complicated yet unsolved problem. In this paper, we propose a novel algorithm that can calculate the minimum cost for storing and regenerating datasets in clouds, i.e. whether datasets should be stored or deleted, and furthermore where to store or to regenerate whenever they are reused. This minimum cost also achieves the best trade-off among computation, storage and bandwidth costs in multiple clouds. Comprehensive analysis and rigid theorems guarantee the theoretical soundness of the paper, and general (random) simulations conducted with popular cloud service providers' pricing models demonstrate the excellent performance of our approach.

Destins des S-RNases et interactions moléculaires dans le tube pollinique dans le cadre de l’auto-incompatibilité gamétophytique chez Solanum chacoense

L’auto-incompatibilité (AI) est une barrière reproductive prézygotique qui permet aux pistils d’une fleur de rejeter leur propre pollen. Les systèmes d’AI peuvent prévenir l’autofertilisation et ainsi limiter l’inbreeding. Dans l’AI gamétophytique, le génotype du pollen détermine son propre phénotype d’incompatibilité, et dans ce système, les déterminants mâles et femelles de l’AI sont codés par un locus multigénique et multi-allélique désigné le locus S. Chez les Solanaceae, le déterminant femelle de l’AI est une glycoprotéine stylaire extracellulaire fortement polymorphique possédant une activité ribonucléase et désignée S-RNase. Les S-RNases montrent un patron caractéristique de deux régions hypervariables (HVa et HVb), responsables de leur détermination allélique, et cinq régions hautement conservées (C1 à C5) impliquées dans l’activité catalytique ou la stabilisation structurelle de ces protéines. Dans ce travail, nous avons investigué plusieurs caractéristiques des S-RNases et identifié un nouveau ligand potentiel aux S-RNases chez Solanum chacoense. L’objectif de notre première étude était l’élucidation du rôle de la région C4 des S-RNases. Afin de tester l’hypothèse selon laquelle la région C4 serait impliquée dans le repliement ou la stabilité des S-RNases, nous avons généré un mutant dans lequel les quatre résidus chargés présents en région C4 furent remplacés par des résidus glycine. Cette protéine mutante ne s’accumulant pas à des niveaux détectables, la région C4 semble bien avoir un rôle structurel. Afin de vérifier si C4 est impliquée dans une liaison avec une autre protéine, nous avons généré le mutant R115G, dans lequel un acide aminé chargé fût éliminé afin de réduire les affinités de liaison dans cette région. Ce mutant n’affectant pas le phénotype de rejet pollinique, il est peu probable que la région C4 soit impliquée dans la liaison des S-RNases avec un ligand ou leur pénétration à l’intérieur des tubes polliniques. Enfin, le mutant K113R, dans lequel le seul résidu lysine conservé parmi toutes les S-RNases fût remplacé par un résidu arginine, fût généré afin de vérifier si cette lysine était un site potentiel d’ubiquitination des S-RNases. Toutefois, la dégradation des S-RNases ne fût pas inhibée. Ces résultats indiquent que C4 joue probablement un rôle structurel de stabilisation des S-RNases. Dans une seconde étude, nous avons analysé le rôle de la glycosylation des S-RNases, dont un site, en région C2, est conservé parmi toutes les S-RNases. Afin d’évaluer la possibilité que les sucres conjugués constituent une cible potentielle d’ubiquitination, nous avons généré une S11-RNase dont l‘unique site de glycosylation en C2 fût éliminé. Ce mutant se comporte de manière semblable à une S11-RNase de type sauvage, démontrant que l’absence de glycosylation ne confère pas un phénotype de rejet constitutif du pollen. Afin de déterminer si l’introduction d’un sucre dans la région HVa de la S11-RNase pourrait affecter le rejet pollinique, nous avons généré un second mutant comportant un site additionnel de glycosylation dans la région HVa et une troisième construction qui comporte elle aussi ce nouveau site mais dont le site en région C2 fût éliminé. Le mutant comportant deux sites de glycosylation se comporte de manière semblable à une S11-RNase de type sauvage mais, de manière surprenante, le mutant uniquement glycosylé en région HVa peut aussi rejeter le pollen d’haplotype S13. Nous proposons que la forme non glycosylée de ce mutant constitue un allèle à double spécificité, semblable à un autre allèle à double spécificité préalablement décrit. Il est intéressant de noter que puisque ce phénotype n’est pas observé dans le mutant comportant deux sites de glycosylation, cela suggère que les S-RNases ne sont pas déglycosylées à l’intérieur du pollen. Dans la dernière étude, nous avons réalisé plusieurs expériences d’interactions protéine-protéine afin d’identifier de potentiels interactants polliniques avec les S-RNases. Nous avons démontré que eEF1A, un composant de la machinerie de traduction chez les eucaryotes, peut lier une S11-RNase immobilisée sur résine concanavaline A. Des analyses de type pull-down utilisant la protéine eEF1A de S. chacoense étiquetée avec GST confirment cette interaction. Nous avons aussi montré que la liaison, préalablement constatée, entre eEF1A et l’actine est stimulée en présence de la S11-RNase, bien que cette dernière ne puisse directement lier l’actine. Enfin, nous avons constaté que dans les tubes polliniques incompatibles, l’actine adopte une structure agrégée qui co-localise avec les S-RNases. Ces résultats suggèrent que la liaison entre eEF1A et les S-RNases pourrait constituer un potentiel lien fonctionnel entre les S-RNases et l’altération du cytosquelette d’actine observée lors des réactions d’AI. Par ailleurs, si cette liaison est en mesure de titrer les S-RNases disponibles à l’intérieur du tube pollinique, ce mécanisme pourrait expliquer pourquoi des quantités minimales ou « seuils » de S-RNases sont nécessaires au déclenchement des réactions d’AI.

Influência na qualidade final de metais retificados através da variação da velocidade de mergulho

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência das técnicas de mínima quantidade de lubrificante, refrigeração otimizada e refrigeração convencional na qualidade de peças produzidas com aços endurecidos no processo de retificação

The influence of minimum lubrication, optimized and conventional cooling at different flows and application rates of cutting fluids on the quality of hardened-steel pieces produced by external cylindrical plunge grinding with super-abrasive grinding wheels with low CBN concentrations was verified. The analysis of the quality of the pieces was performed through the assessment of the behavior of the specific energy of the grinding, roughness, roundness deviation, and the generated residual stress. By analyzing of the application ways and of the several flows and application rates of the cutting fluid, one could encounter lubrication/cooling conditions that enable the reduction in cutting fluid volume, reduction in grinding time without compromising the dimensional parameters (superficial finishing, surface integrity). Regarding the different applications of cutting fluids, it could be noted the optimized application for higher velocities has presented the best performance, demonstrating the effectiveness of the new concept of nozzle utilized.

A influência da aplicação de fluído de corte no torneamento da liga de aluminio AA 7075

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de método limpo para a determinação de uréia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise da influência da velocidade de mergulho na retificação de aços endurecidos utilizando refrigeração otimizada

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da aplicação de mínima quantidade de fluido no fresamento de acabamento da liga Ti-6Al-4V

Pós-graduação em Engenharia Mecânica - FEG