Processing and characterization of alpha-elastin electrospun membranes

Elastin isolated from fresh bovine ligaments was dissolved in a mixture of 1,1,1,3,3,3-Hexafluoro-2-propanol and water and electrospun into fiber membranes under different processing conditions. Fiber mats of randomly and aligned fibers were obtained with fixed and rotating ground collectors and fibrils were composed by thin ribbons whose width depends on electrospinning conditions; fibrils with 721 nm up to 2.12 m width were achieved. After cross-linking with glutaraldehyde, -elastin can uptake as much as 1700 % of PBS solution and a slight increase on fiber thickness was observed. The glass transition temperature of electrospun fiber mats was found to occur at ~ 80 ºC. Moreover, -Elastin showed to be a perfect elastomeric material, and no mechanical hysteresis was found in cycle mechanical measurements. The elastic modulus obtained for oriented and random fibers mats in a PBS solution was 330 ± 10 kPa and 732 ± 165 kPa, respectively. Finally, the electrospinning and cross-linking process does not inhibit MC-3T3-E1 cell adhesion. Cell culture results showed good cell adhesion and proliferation in the cross-linked elastin fiber mats.

Modifying fish gelatin electrospun membranes for biomedical applications: cross- linking and swelling behavior

Development of suitable membranes is a fundamental requisite for tissue and biomedical engineering applications. This work presents fish gelatin random and aligned electrospun membranes cross-linked with glutaraldehyde (GA). It was observed that the fiber average diameter and the morphology is not influenced by the GA exposure time and presents fibers with an average diameter around 250 nm. Moreover, when the gelatin mats are immersed in a phosphate buffered saline solution (PBS), they can retain as much as 12 times its initial weight of solution almost instantaneously, but the material microstructure of the fiber mats changes from the characteristic fibrous to an almost spherical porous structure. Cross-linked gelatin electrospun fiber mats and films showed a water vapor permeability of 1.37 ± 0.02 and 0.13 ± 0.10 (g.mm)/(m2.h.kPa), respectively. Finally, the processing technique and cross-linking process does not inhibit MC-3T3-E1 cell adhesion. Preliminary cell culture results showed good cell adhesion and proliferation in the cross-linked random and aligned gelatin fiber mats.

A practical framework for the generation and selection of strategic plans of action, The relevance of timeframe considerations and a systems thinking approach

The paper proposes a methodology especially focused on the generation of strategic plans of action, emphasizing the relevance of having a structured timeframe classification for the actions. The methodology explicitly recognizes the relevance of long-term goals as strategic drivers, which must insure that the complex system is capable to effectively respond to changes in the environment. In addition, the methodology employs engineering systems techniques in order to understand the inner working of the system and to build up alternative plans of action. Due to these different aspects, the proposed approach features higher flexibility compared to traditional methods. The validity and effectiveness of the methodology has been demonstrated by analyzing an airline company composed by 5 subsystems with the aim of defining a plan of action for the next 5 years, which can either: improve efficiency, redefine mission or increase revenues.

Contabilidade Financeira Avançada - Exercícios

Contabilidade Financeira Avançada - Exercícios

A HIPÓTESE INTEGRADORA DA GOVERNANÇA CORPORATIVA E DA RESPONSABILIDADE SOCIAL CORPORATIVA SOB O ENFOQUE DOS DIREITOS HUMANOS

A governança corporativa e a responsabilidade social corporativa são dois instrumentos que têm o caráter de atingir a excelência da organização empresarial. Por sua vez, os mesmos foram instrumentalizados como meio de proteção dos interesses dos agentes privados com vista à potencialização da sociedade empresarial, motivados pela desconfiança dos processos decisórios dos administradores societários. Posteriormente, evoluiram sob a forma de códigos de condutas, ditados pelos organismos de controle empresarial, sempre conservando o caráter voluntário de sua aceitação. Alguns objetivos sequer foram incluídos nos seus processos internos de excelência, como por exemplo os direitos humanos de determinados stakeholders. Esse ponto é o objeto principal desta investigação, que busca evidenciar a hipótese de integração da governança corporativa e da responsabilidade social corporativa sob o enfoque dos direitos humanos. § The Corporate governance and corporate social responsibility are two instruments that have the character to achieve excellence in business organization. On the other hand, they have been exploited as a way of protecting the interests of private agents for enhancement of corporate society, motivated by the distrust of the decision-making process of corporate managers. Later, it evolved in the form of codes of conduct, dictated by the bodies of corporate control, always preserving the voluntary nature of their acceptance. Some objectives were not even included in its internal process of excellence, such as the human rights of certain stakeholders. This point is the main object of this research, which seeks to demonstrate the possibility of integration of corporate governance and corporate social responsibility in the human rights perspective.