2 resultados para Semi-Regenerative Process
em AMS Tesi di Dottorato - Alm@DL - Universit
Resumo:
Supercritical Emulsion Extraction technology (SEE-C) was proposed for the production of poly-lactic-co-glycolic acid microcarriers. SEE-C operating parameters as pressure, temperature and flow rate ratios were analyzed and the process performance was optimized in terms of size distribution and encapsulation efficiency. Microdevices loaded with bovine serum insulin were produced with different sizes (2 and 3 µm) or insulin charges (3 and 6 mg/g) and with an encapsulation efficiency of 60%. The microcarriers were characterized in terms of insulin release profile in two different media (PBS and DMEM) and the diffusion and degradation constants were also estimated by using a mathematical model. PLGA microdevices were also used in a cultivation of embryonic ventricular myoblasts (cell line H9c2 obtained from rat) in a FBS serum free medium to monitor cell viability and growth in dependence of insulin released. Good cell viability and growth were observed on 3 µm microdevices loaded with 3 mg/g of insulin. PLGA microspheres loaded with growth factors (GFs) were charged into alginate scaffold with human Mesenchimal Steam Cells (hMSC) for bone tissue engineering with the aim of monitoring the effect of the local release of these signals on cells differentiation. These “living” 3D scaffolds were incubated in a direct perfusion tubular bioreactor to enhance nutrient transport and exposing the cells to a given shear stress. Different GFs such as, h-VEGF, h-BMP2 and a mix of two (ratio 1:1) were loaded and alginate beads were recovered from dynamic (tubular perfusion system bioreactor) and static culture at different time points (1st, 7th, 21st days) for the analytical assays such as, live/dead; alkaline phosphatase; osteocalcin; osteopontin and Van Kossa Immunoassay. The immunoassay confirmed always a better cells differentiation in the bioreactor with respect to the static culture and revealed a great influence of the BMP-2 released in the scaffold on cell differentiation.
Resumo:
This research aims at contributing to a better understanding of changes in local governments’ accounting and reporting practices. Particularly, ‘why’, ‘what’ and ‘how’ environmental aspects are included and the significance of changes across time. It adopts an interpretative approach to conduct a longitudinal analysis of case studies. Pettigrew and Whipp’s framework on context, content and process is used as a lens to distinguish changes under each dimension and analyse their interconnections. Data is collected from official documents and triangulated with semi-structured interviews. The legal framework defines as boundaries of the accounting information the territory under local governments’ jurisdiction and their immediate surrounding area. Organisational environmental performance and externalities are excluded from the requirements. An interplay between the local outer context, political commitment and organisational culture justifies the implementation of changes beyond what is regulated and the implementation of transformational changes. Local governments engage in international networks to gain access to funding and implement changes, leading to adopting the dominant environmental agenda. Key stakeholders, like citizens, are not engaged in the accounting and reporting process. Thus, there is no evidence that the environmental aspects addressed and related changes align with stakeholders’ needs and expectations, which jeopardises its significance. Findings from the current research have implications in other EU member states due to the harmonisation of accounting and reporting practices and the common practice across the EU in using external funding to conceptualise and implement changes. This implies that other local governments could also be representing a limited account related to environmental aspects.