Simulating scratch behavior of polymers with mesoscopic molecular dynamics

Part replacement and repair is needed in structures with moving parts because of scratchability and wear. In spite of some accumulation of experimental evidence, scratch resistance is still not well understood. We have applied molecular dynamics to study scratch resistance of amorphous polymeric materials through computer simulations. As a first approach, a coarse grain model was created for high density polyethylene at the mesoscale. We have also extended the traditional approach and used real units rather than reduced units (to our knowledge, for the first time), which enable an improved quantification of simulation results. The obtained results include analysis of penetration depth, residual depth and recovery percentage related to indenter force and size. Our results show there is a clear effect from these parameters on the tribological properties. We also discuss a "crooked smile" effect on the scratched surface and the reasons for its appearance.

Certification and integration of environment with quality and safety – a path to sustained success

According to Wright [1] certification of products and processes began during the 1960’s in the manufacturing industry, as a tool to control and assure the quality/conformity of products and services provided by suppliers to customers/consumers. Thus, the series of ISO 9000 was published first time, in 1987 and it was been created with a flexible character, to be reviewed periodically. Later, were published others normative references, which highlight the ISO 14001 in 1996 and OHSAS 18001 in 1999. This was also, the natural sequence of the certification processes in the organizations, i.e., began with the certification of quality management systems (QMS) followed by the environmental management systems (EMS) and after for the Occupational Health and Safety Management System (OHSMS). Hence, a high percentage of organizations with an EMS, in accordance with the ISO 14001, had also implemented, a certified QMS, in accordance with ISO 9001. At first the implementation of a QMS was particularly relevant in high demanding activity sectors, like the automotive and aeronautical industries, but it has rapidly extended to every activity sector, becoming a common requisite of any company worldwide and a factor of competitiveness and survival. Due to the increasingly demanding environmental legislation in developed countries, companies nowadays are required to seriously take into consideration not only environmental aspects associated to the production chain itself, but also to the life cycle of their products.

Residents’ perceptions on impacts of hosting the “Guimarães 2012 European Capital of Culture”: comparisons of the pre-and post-2012 ECOC

Residents tend to have high expectations about the benefits of hosting a mega‐event. So, it was not surprising that the nomination of Guimarães, Portugal, as the 2012 European Capital of Culture (2012 ECOC) had raised great expectations in the local community towards its socio‐economic and cultural benefits. The present research was designed to examine the Guimarães residents’ perceptions on the impacts of hosting the 2012 ECOC approached in two different time schedules, the pre‐ and the post‐event, trying to capture the evolution of the residents` evaluation of its impacts. For getting the data, two surveys were applied to Guimarães` residents, one in the pre‐event phase, in 2011, and another in the post‐event phase, in 2013. This approach is uncommonly applied to Portugal data and it is even the first time it was done to a Portuguese European Capital of Culture. After a factor analysis, the results of t‐tests indicate that there were significant differences (p<0.05) between the samples from the pre‐ and post‐2012 ECOC on two positive impact factors (Community’ benefits and Residents’ benefits) and one negative impact factor (Economic, social and environmental costs). Respondents also showed a negative perception of the impacts in all dimensions, except Changes in habits of Guimarães residents.

Targeting lactate transport suppresses in vivo breast tumour growth

Background: Most cancers, including breast cancer, have high rates of glucose consumption, associated with lactate production, a process referred as “Warburg effect”. Acidification of the tumour microenvironment by lactate extrusion, performed by lactate transporters (MCTs), is associated with higher cell proliferation, migration, invasion, angiogenesis and increased cell survival. Previously, we have described MCT1 up-regulation in breast carcinoma samples and demonstrated the importance of in vitro MCT inhibition. In this study, we performed siRNA knockdown of MCT1 and MCT4 in basal-like breast cancer cells in both normoxia and hypoxia conditions to validate the potential of lactate transport inhibition in breast cancer treatment. Results: The effect of MCT knockdown was evaluated on lactate efflux, proliferation, cell biomass, migration and invasion and induction of tumour xenografts in nude mice. MCT knockdown led to a decrease in in vitro tumour cell aggressiveness, with decreased lactate transport, cell proliferation, migration and invasion and, importantly, to an inhibition of in vivo tumour formation and growth. Conclusions: This work supports MCTs as promising targets in cancer therapy, demonstrates the contribution of MCTs to cancer cell aggressiveness and, more importantly, shows, for the first time, the disruption of in vivo breast tumour growth by targeting lactate transport.