Síntese e caracterização do poli(ácido láctico) para potencial uso em sistemas de liberação controlada de fármacos

With the advances in medicine, life expectancy of the world population has grown considerably in recent decades. Studies have been performed in order to maintain the quality of life through the development of new drugs and new surgical procedures. Biomaterials is an example of the researches to improve quality of life, and its use goes from the reconstruction of tissues and organs affected by diseases or other types of failure, to use in drug delivery system able to prolong the drug in the body and increase its bioavailability. Biopolymers are a class of biomaterials widely targeted by researchers since they have ideal properties for biomedical applications, such as high biocompatibility and biodegradability. Poly (lactic acid) (PLA) is a biopolymer used as a biomaterial and its monomer, lactic acid, is eliminated by the Krebs Cycle (citric acid cycle). It is possible to synthesize PLA through various synthesis routes, however, the direct polycondensation is cheaper due the use of few steps of polymerization. In this work we used experimental design (DOE) to produce PLAs with different molecular weight from the direct polycondensation of lactic acid, with characteristics suitable for use in drug delivery system (DDS). Through the experimental design it was noted that the time of esterification, in the direct polycondensation, is the most important stage to obtain a higher molecular weight. The Fourier Transform Infrared (FTIR) spectrograms obtained were equivalent to the PLAs available in the literature. Results of Differential Scanning Calorimetry (DSC) showed that all PLAs produced are semicrystalline with glass transition temperatures (Tgs) ranging between 36 - 48 °C, and melting temperatures (Tm) ranging from 117 to 130 °C. The PLAs molecular weight characterized from Size Exclusion Chromatography (SEC), varied from 1000 to 11,000 g/mol. PLAs obtained showed a fibrous morphology characterized by Scanning Electron Microscopy (SEM)

Impacto urbano ocasionado por empreendimentos da construção civil no entorno da zona de proteção ambiental (zpa-6), Vila de Ponta Negra, Natal/RN

The process of urbanization in recent decades has generated considerable seriousness of problems relating to the use and occupation physical environment of cities. The concentration of population, economic activities and technological standards have reinforced an existing urban environment highly degraded as a consequence of the development style that leads to the predatory use of natural resources. In this context, cities as centers of production and consumption, have the most serious problems of environmental degradation. This study investigated the impacts of the municipal building projects to large-scale vertical in the town of Vila de Ponta Negra, Natal-RN, given the proximity to the Environmental Protection Area (ZPA-6) and considering its environmental importance , scenic, landscape and tourism for the city of Natal-RN. The fragility of the licensing process and the failure of the assumptions in the analysis, objective and subjective, for the granting of environmental permits for the building construction projects, specifically those set out in the surroundings of the Environmental Protection Area (ZPA-6) and fundamental importance of landscape and tourism for the city of Natal, has aroused the concern of local people in and of itself the Government, faced with the probable impacts that will affect greatly the Vila de Ponta Negra. The methodology used to achieve the intended objectives will be the literature review, questionnaire to the surrounding population and the Government, as well as findings on the spot, through the photographic record. The beneficiaries of the license, if the entrepreneurs, have been affected because of the granting of licensing act of investing large amount of capital in the works. Additionally, with distrust of the population, since they are to discredit the public system of environmental management have guessed by the probability of imbalance to the environment and structural damage to the Vila de Ponta Negra, where such failure to support energy, lack of regular supply of water , lack of sanitation and access roads sufficient for the flow of motor vehicles in these areas, among other factors. Thus, this work will contribute to the diagnosis and solutions to the problem in question, so that the Government will effectively fulfill its social management of ecologically balanced environment of continuing urban development in Natal, Brazil

Mudanças climáticas globais e o compromisso pró-ecológico de adolescentes natalenses

In recent years, much has been discussed about global climate changes (GCCs), popularly known as global warming. The scientific evidences point out to the influence of human actions for its drastic intensification. Therefore, studies of the psychological aspects involved become relevant. This study aimed at the investigation of the views of adolescents concerning GCCs, and the possible relations between those views and their pro-ecological commitment. Such commitment is measured by willingness for engagement in pro-environmental behaviors; environmentalism attitudes, like ecocentric and anthropocentric; consideration of future consequences; and ecological worldviews. Participants were 348 adolescents who answered a questionnaire containing questions about socio-demographic data, open questions about the practice of environmental care, and about GCCs, and the scales of Ecocentric and Anthropocentric Environmentalism, the Consideration of Future Consequences and the Ecological Worldviews assessment scale. From the inter-relationships between variables, procedures carried out by means of descriptive and correlacional statistics, it was observed that 55% of teenagers said that they did not engage in actions of environmental care, which was associated with apathyanthropocentric, immediatism, and individualism. The consideration of future consequences joined the practice of environmental care, corroborating evidence from the literature. It was evident that views concerning GCCs were superficial; adolescents perceive it as a generic environmental problem, and are confused with other problems such as pollution. This study found no association between views about GCCs and the indicators of pro-ecological commitment, perhaps due to the conceptual confusion about the subject. However, the lack of environmental care actions and other indicators of non-commitment (apathy-anthropocentric, individualism and immediatism) were associated with conceptually poor or incomplete responses (with no indication of cause, consequence or responsibility for the problem), demonstrating diminished knowledge and the failure to consider these issues