On the interaction of bovine serum albumin with ionic surfactants: Temperature induced EPR changes of a maleimide nitroxide reflect local protein dynamics and probe solvent accessibility

The interaction of bovine serum albumin (BSA) with the ionic surfactants sodium dodecylsulfate (SDS, anionic), cetyltrimethylammonium chloride (CTAC, cationic) and N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS, zwitterionic) was studied by electron paramagnetic resonance (EPR) spectroscopy of spin label covalently bound to the single free thiol group of the protein. EPR spectra simulation allows to monitor the protein dynamics at the labeling site and to estimate the changes in standard Gibbs free energy, enthalpy and entropy for transferring the nitroxide side chain from the more motionally restricted to the less restricted component. Whereas SDS and CTAC showed similar increases in the dynamics of the protein backbone for all measured concentrations. HPS presented a smaller effect at concentrations above 1.5 mM. At 10 mM of surfactants and 0.15 mM BSA, the standard Gibbs free energy change was consistent with protein backbone conformations more expanded and exposed to the solvent as compared to the native protein, but with a less pronounced effect for HPS. In the presence of the surfactants, the enthalpy change, related to the energy required to dissociate the nitroxide side chain from the protein, was greater, suggesting a lower water activity. The nitroxide side chain also detected a higher viscosity environment in the vicinity of the paramagnetic probe induced by the addition of the surfactants. The results suggest that the surfactant-BSA interaction, at higher surfactant concentration, is affected by the affinities of the surfactant to its own micelles and micelle-like aggregates. Complementary DLS data suggests that the temperature induced changes monitored by the nitroxide probe reflects local changes in the vicinity of the single thiol group of Cys-34 BSA residue. (C) 2011 Elsevier B.V. All rights reserved.

On administrative borders and accessibility to public services: : The case of hospitals in Sweden.

An administrative border might hinder the optimal allocation of a given set of resources by restricting the flow of goods, services, and people. In this paper we address the question: Do administrative borders lead to poor accessibility to public service such as hospitals? In answering the question, we have examined the case of Sweden and its regional borders. We have used detailed data on the Swedish road network, its hospitals, and its geo-coded population. We have assessed the population’s spatial accessibility to Swedish hospitals by computing the inhabitants’ distance to the nearest hospital. We have also elaborated several scenarios ranging from strongly confining regional borders to no confinements of borders and recomputed the accessibility. Our findings imply that administrative borders are only marginally worsening the accessibility.

On the interaction of bovine serum albumin with ionic surfactants: Temperature induced EPR changes of a maleimide nitroxide reflect local protein dynamics and probe solvent accessibility

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of door handles design in effort perception: accessibility and usability

The application of ergonomics in product design is essential to its accessibility and usability. The development of manual devices should be based on ergonomic principles. Effort perception analysis is an essential approach to understand the physical and subjective aspects of the interface. The objective of the present study was to analyze the effort perception during a simulated task with different door handles by Portuguese subjects of both genders and different ages. This transversal study agreed with ethical aspects. 180 subjects of both genders pertaining to three age groups have participated. Five door handles with different shapes were evaluated. A subjective numeric rating scale of 5 levels was used to evaluate the effort. For statistical analysis it was applied the Friedman non-parametric test. The results have showed no significant differences of effort perception in door handles "A" and "B"; "A" and "D"; and "D" and "C". Door handle "E" presented the lowest values of all. In general, there's an inverse relationship between the results of biomechanical studies and the effort perception of the same task activity. This shows that door handles design influence directly these two variables and can interfere in the accessibility and usability of these kinds of products.

Human Accessibility Modelling Applied to Protected Areas Management

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

Interfacial surface charge and free accessibility to the PLA(2)-active site-like region are essential requirements for the activity of Lys49 PLA(2) homologues

Lys49 phospholipase A(2) homologues are highly myotoxic and cause extensive tissue damage but do not display hydrolytic activity towards natural phospholipids. The binding of heparin, heparin derivatives and polyanionic compounds such as suramin result in partial inhibition (up to 60%) of the myotoxic effects due to a change in the overall charge of the interfacial surface. In vivo experiments demonstrate that polyethylene glycol inhibits more than 90% of the myotoxic effects without exhibiting secondary toxic effects. The crystal structure of bothropstoxin-I complexed with polyethylene glycol reveals that this inhibition is due to steric hindrance of the access to the PLA(2)-active site-like region. These two inhibitory pathways indicate the roles of the overall surface charge and free accessibility to the PLA2-active site-like region in the functioning of Lys49 phospholipases A(2) homologues. Molecular dynamics simulations, small angle X-ray scattering and structural analysis indicate that the oligomeric states both in solution and in the crystalline states of Lys49 phospholipases A2 are principally mediated by hydrophobic contacts formed between the interfacial surfaces. These results provide the framework for the potential application of both clinically approved drugs for the treatment of Viperidae snakebites. (c) 2006 Elsevier Ltd. All rights reserved.

Assessment of tuberculosis treatment accessibility for patients co-infected or not with the human immunodeficiency virus

This study aimed to evaluate accessibility to treatment for people with TB co-infected or not with HIV. This cross-sectional study addressed issues regarding accessibility to treatment in a city in the interior of Sao Paulo state, Brazil. The instrument Primary Care Assessment Tool was utilized with 95 people. To evaluate access to treatment, Student's t test was used. The mean scores of variables were analyzed separately and compared between two groups (people with TB co-infected with HIV and people with TB not co-infected with HIV). Mean scores showed that HIV co-infected people presented greater difficulties in gaining access than those not co-infected. Professionals visited co-infected people more often when compared to those not co-infected; the co-infected people almost never accessed treatment for their disease in the Health Unit nearest their home. There is, therefore, the need for greater integration and communication between the programs for treatment of Tuberculosis and STD/AIDS.

Accessibility in Digital Television: Designing Remote Controls

Free to air television is still an important tool to provide information and communication in many countries. Therefore, the universal access to the television system is very important. This paper presents a set of Digital Television accessible remote control devices designed for the Brazilian Digital Television. A research was conducted, interviewing people with disabilities in Brazil. Three remote control models were proposed, consolidating the main identified requirements, being accessible for a diverse group of impairments.

CTAB, Triton X-100 and freezing-thawing treatments of Candida guilliermondii: Effects on permeability and accessibility of the glucose-6-phosphate dehydrogenase, xylose reductase and xylitol dehydrogenase enzymes

Cells of Candida guilliermondii (ATCC 201935) were permeabilised with surfactant treatment (CTAB or Triton X-100) or a freezing-thawing procedure. Treatments were monitored by in situ activities of the key enzymes involved in xylose metabolism, that is, glucose-6-phosphate dehydrogenase (G6PD), xylose reductase (XR) and xylitol dehydrogenase (XD). The permeabilising ability of the surfactants was dependent on its concentration and incubation time. The optimum operation conditions for the permeabilisation of C. guilliermondii with surfactants were 0.41 mM (CTAB) or 2.78 mM (Triton X-100), 30 degrees C, and pH 7 at 200 rpm for 50 min. The maximum permeabilisation measured in terms of the in situ G6PD activity observed was, in order, as follows: CTAB (122.4 +/- 15.7 U/g(cells)) > freezing-thawing, , (54.3 +/- 1.9 U/g(cells)) > Triton X-100 (23.5 +/- 0.0 U/g(cells)). These results suggest that CTAB surfactant is more effective in the permeabilisation of C. guilliermondii cells in comparison to the freezing-thawing and Triton X-100 treatments. Nevertheless, freezing-thawing was the only treatment that allowed measurable in situ XR activity. Therefore, freezing-thawing permeabilised yeast cells could be used as a source of xylose reductase for analytical purposes or for use in biotransformation process such as xylitol preparation from xylose. The level of in situ xylose reductase was found to be 13.2 +/- 0.1 U/g(cells).

Accessibility and demand at an Emergency Care Unit: the user's perspective

AIM: To analyze the search for Emergency Care (EC) in the Western Health District of Ribeirão Preto (São Paulo), in order to identify the reasons why users turn to these services in situations that are not characterized as urgencies and emergencies. METHODS: A qualitative and descriptive study was undertaken. A guiding script was applied to 23 EC users, addressing questions related to health service accessibility and welcoming, problem solving, reason to visit the EC and care comprehensiveness. RESULTS: The subjects reported that, at the Primary Health Care services, receiving care and scheduling consultations took a long time and that the opening hours of these services coincide with their work hours. At the EC service, access to technologies and medicines was easier. CONCLUSION: Primary health care services have been unable to turn into the entry door to the health system, being replaced by emergency services, putting a significant strain on these services' capacity.

Accessibility and visibility of academic and scientific production of the University of São Paulo (USP), Brazil

ACADEMIC CONTENTS: Digital Library of Theses and Dissertations, eAULAS, Open Educational Resources. SCIENTIFIC CONTENTS: Digital Library of USP Intellectual Production, Scientific Journals Portal. OTHER CONTENTS: Rare books, Maps, Images.

Accessibility as a determinant of environmental dynamics in socio-economic disparities in mainland Southeast Asia

Access and accessibility are important determinants of people’s ability to utilise natural resources, and have a strong impact on household welfare. Physical accessibility of natural resources, on the other hand, has generally been regarded as one of the most important drivers of land-use and land-cover changes. Based on two case studies, this article discusses evidence of the impact of access to services and access to natural resources on household poverty and on the environment. We show that socio-cultural distances are a key limiting factor for gaining access to services, and thereby for improved household welfare. We also discuss the impact of socio-cultural distances on access to natural resources, and show that large-scale commercial exploitation of natural resources tends to occur beyond the spatial reach of socio-culturally and economically marginalised population segments. We conclude that it is essential to pay more attention to improving the structural environment that presently leaves social minority groups marginalised. Innovative approaches that use natural resource management to induce poverty reduction – for example, through compensation of local farmers for environmental services – appear to be promising avenues that can lead to integration of the objectives of poverty reduction and sustainable environmental stewardship.