Evolution in the composition of human skin surface lipids during their accumulation on scalp and hair

Qualitative examination of human surface lipids collected using a surfactant solution shows that there are no significant differences between individuals when the samples are collected after one day, starting from clean hair and scalp. On the contrary, samples collected after 4 days reveal discrepancies within the population, related to the oily hair symptom.
An evolution in the composition of the recovered mixture occurs during the 1–4 days accumulation period, which mainly results in an increased unsaturation of the total (free + glycerides) fatty acids fraction isolated after saponification.
A two-step mechanism is proposed to account for the observed evolution: in a first step, free fatty acids are cleaved from glycerides by the well known enzymatic hydrolysis. Analytical determinations show that this process is structure dependant, the straight chain saturated acids being more readily hydrolyzable than the unsaturated and branched chain species. In a second step, free fatty acids are immobilized on the keratinic fibers, by a process which involves the formation of Ca salts.
This evolution results in a decreased viscosity of the skin surface lipids and in an increase of the low temperature melting fraction of the mixture. Its extent is more or less pronounced, depending upon the individuals. Subjects who exhibit extensive evolution are affected by the oily hair symptom.
Evolution de la composition des lipides superficiels humains durant leur accumulation sur le scalp et les cheveux     

Formal Definition of a User-Adaptive and Length-Optimal Routing Graph for Complex Indoor Environments

Car routing solutions are omnipresent and solutions for pedestrians also exist. Furthermore, public or commercial buildings are getting bigger and the complexity of their internal slructure has increased. Consequently, the need for indoor routing solutions has emerged. Some prototypes are available, but they still lack semantically-enriched modelling (e.g., access constraints, labels, etc.) and are not suitable for providing user-adaptive length-optimal routing in complex buildings. Previous approaches consider simple rooms,concave rooms, and corridors, but important characteristics such as distinct areas in huge rooms and solid obstacles inside rooms are not considered at all, although such details can increase navigation accuracy. By formally defining a weighted indoor routing graph, it is possible to create a detailed and user-adaptive model for route computation. The defined graph also contains semantic information such as room labels, door accessibility constraints, etc. Furthermore, one-way paths inside buildings are considered, as well as three-dimensional building pans, e.g., elevators or stairways. A hierarchical structure is also possible with the presented graph model.     

Percutaneous absorption of p-phenylene diamine during an actual hair dyeing procedure

An analytical method has been developed that allows the determination of p-phenylene diamine derivatives in urinary samples collected from women after hair dyeing with commercial formulations. During an on-line flash hydrolysis of the urine, a number of metabolites of p-phenylene diamine were hydrolyzed to free p-phenylene diamine, which was then determined using gas chromatography-mass spectrometry. The excretion of metabolites of p-phenylene diamine could be followed during 24 or 48 hours after the dye had been applied. Most of the p-phenylene diamine cleaved by the flash hydrolysis procedure was, in fact, involved in the N,N'-diacetyl combination. The dose excretion for p-phenylene diamine as measured by this method was comparable to that found by other authors who made use of radioactively labelled material. The present analytical method can be used to evaluate procedures intended to decrease the percutaneous absorption of p-phenylene diamine. Thus, a five- to ten-fold decrease in its penetration was observed by protecting the scalp with clay before applying the dyeing composition.     

Guide path design and location of load pick-up/drop-off points for an automated guided vehicle system

The guide path layout for an automated guided vehicle system (AGVS) is a critical component in the overall design of a flexible manufacturing system (FMS) that utilizes AGVs for materials handling. Not only does it affect the total distance travelled by the vehicles but it also affects vehicle requirements and space utilization. In this study, the problem of selecting the guide path as well as the location of pick-up and drop-off points for outward and inward bound parts to departments is addressed. The problem is modelled and solved as a linear integer program with the objective of minimizing the total distance travelled.     

Differential thermal analysis of human sebum as a new approach to rheological behaviour

The oily aspect of a hair is not only the consequence of an excessive lipidic production on the scalp; the quality of the fatty mixture should also be considered.
Differential scanning calorimetry (DSC) is a useful tool for qualitative examination of human sebum. The melting curves recorded using this technique characterise the seborrhoeic state of the subject, their profile being related to the clinical appreciation.
Data from DSC are correlated with other physico-chemical characteristics of sebum, especially with the proportion of unsaturated fatty acids in the whole fatty acids fraction.
The straight chain monoenic acids have been more closely examined. A number of positional isomers can be seen; the distribution of the C₁₈ isomers varies according to the seborrhoeic state of the subject.
L'analyse énthalpique differentielle du sébum. Une nouvelle approche concernant la rhéologie.     

Iterators,Schedulers, and Distributed-memory Parallelism

In previous work, we demonstrated the advantages of encapsulating query evaluation algorithms as ‘iterators’ for sequential and parallel query evaluation. Unfortunately, those earlier models have a severe drawback with respect to resource allocation in distributed-memory systems. Since threads may be initiated long before they actually perform useful work, thread placement decisions may be suboptimal. In this paper, we briefly review the iterator model and then extend it to support bottom-up, just-in-time activation of appropriate query plan fragments as well as local and global synchronization and communication among sibling threads. Some of the algorithms described here may seem intricate; however, the intricacy is encapsulated entirely in the parallelism or ‘exchange’ iterator, thus freeing developers of data manipulation iterators to focus on the specific algorithms at hand, instead of on mechanisms for parallelism. Moreoever, code fragments extracted from an operational prototype demonstrate the ease with which our suggestions can be implemented. Run-time overhead and performance of our techniques are identical to those of earlier, less extensible techniques for bottom-up activation; the benefits of the presented techniques are their clean design, abstraction, extensibility, and the resulting ease of maintenance and enhancement.     

NATIVITY,ETHNICITY, AND RESIDENTIAL RELOCATION: THE EXPERIENCE OF HMONG REFUGEES AND AFRICAN AMERICANS DISPLACED FROM PUBLIC HOUSING

ABSTRACT: This article focuses on how the experiences of refugee public housing residents differ from those of other public housing residents when they participate in housing dispersal programs. An analysis of the spatial resettlement patterns and survey responses of Hmong and African‐American public housing residents who were involuntarily relocated from public housing in Minneapolis, MN indicates the extent to which residents resettled in ethnically concentrated neighborhoods and their satisfaction with their new housing arrangements and neighborhoods. Research results suggest that Hmong did not settle in ethnically concentrated neighborhoods to the same extent as African Americans after relocation, and experienced lower levels of satisfaction in their new housing arrangements and neighborhoods. These findings indicate that the outcomes for residents involved in housing dispersal programs may depend in part on nativity status.     

WHERE HAVE ALL THE TOWERS GONE? THE DISMANTLING OF PUBLIC HOUSING IN U.S. CITIES

ABSTRACT: Public housing authorities (PHAs) across the country are demolishing and selling off public housing units. Although some of the units are being replaced in mixed‐income developments, most are not; the subsidies instead are being shifted into household‐based vouchers. Thus, in most cases the loss of these units is a permanent reduction in the nation's public housing stock. Demolition efforts are more extensive in some cities than in others. This paper analyzes public housing removal in the largest cities of the United States to explain the pattern of demolitions taking place. The analysis reveals that public housing removal is most prevalent in cities facing gentrification pressures, and in cities in which the management of public housing by the local housing authorities was subpar. Public housing removals are also associated with higher levels of racial segregation and violent crime.     

Revenge Of The Property Owners: Community Development and the Politics of Property

ABSTRACT: This study examines the conflict between inner city property owners and lower income tenants for control of neighborhood development agendas and community-based organizations. Utilizing a case study of Minneapolis and St. Paul, the authors investigated neighborhood conflicts over community revitalization. In a number of neighborhoods in the two cities, the community organization has come to be dominated by property owners espousing an “ideology of property” hostile to affordable housing. This has led to tension and conflict between neighborhood organizations pursuing owner interests and community development corporations focusing on low income housing.