1,590 research outputs found
ADIPOSE-DERIVED MULTIPOTENT STROMAL CELLS IN REGENERATIVE MEDICINE
Beside adipose tissue had been considered a discard product for many years, recently its role as regenerative agent has been widely recognized. Adipose tissue is a connective tissue constituted of adipocytes interspersed with collagen fibers and stromal vascular fraction (SVF), composed of adipose-derived multipotent stromal cells (ASCs), pre-adipocytes, fibroblasts, vascular endothelial cells and immune cells. The regenerative role is played specifically by the SVF and, inside it, especially by the ASCs, by secreting angiogenetic, anti-apoptotic, antiinflammatory and immunomodulatory growth factors. Surgeons use different strategies to reconstruct or repair damaged tissues and organs through adipose tissue. Among them, the most effective are the autologous fat transfer and tissue engineering. In the autologous fat transfer, autologous adipose tissue is harvested from one part of the body, purified through some processing techniques and reinjected where necessary. In tissue engineering, some scaffolds made of natural or synthetic materials are used in combination with ASCs and, sometimes, growth factors to repair or reconstruct tissues. The first experimental part of this doctoral thesis analyzes the in vitro performances of one automated closed device and two different disposable kits to process adipose tissue in comparison with the enzymatic digestion, which is the gold-standard technique. All three methods produce micrografts rich of ASCs. Parameters such as ASCs phenotype, viability, growth and replicative rate have been observed. The second experimental part of this thesis analyzes the in vitro and in vivo performances of different formulations of hyaluronic acid, a natural and very promising material to regenerate tissues, when combined with ASCs. Parameters such as ASCs viability, interaction with the hyaluronic acid material and adipogenesis have been observed
Cost and benefits of rent control in Kumasi, Ghana
Over the past forty years, rent control has been a feature of housing in Ghana. This study focusses on the housing market in Kumasi, the second largest city in Ghana. The authors examine the characteristics of the rent control regime in force there, and assess the costs and benefits of rent control, on landlords and on tenants, and its effect on the housing stock. Rent control has been successful in ensuring that housing is very inexpensive for most households, in both absolute terms and in the proportion of income devoted to rent. Thesecontrols have deprived landlords of economic returns on their property, causing them to withdraw stock from renting to use for their own family members and to reduce maintenance. However, rent control is not the only constraint on the housing market, in Kumasi or in Ghana. The paper also describes other supply side and regulatory constraints; such as those affecting land, finance, and choice of building design and materials. A number of options for relaxation/decontrol are studied with the aid of a simple present value model. Along with decontrol of new construction it is recommended that floating up and out of controls over a five year period should be considered, along with policy changes to ensure ready supplies of land, finance, and building materials. Such policies are essential, given that private housing investment provides the great majority of rooms in Ghanaian urban areas.Non Bank Financial Institutions,Banks&Banking Reform,Housing Finance,Housing&Human Habitats,Economic Theory&Research
The Application of Macro- and Microfossils to Identify Paleoearthquakes in Sumatra, Indonesia and to Characterize Geomorphic and Ecological Succession on a Marsh Platform After Hurricane Isabel in North Carolina, USA
@font-face { font-family: Verdana ; }@font-face { font-family: Cambria ; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0in 0in 0.0001pt; text-align: justify; line-height: 200%; font-size: 10pt; font-family: Times New Roman ; }div.Section1 { page: Section1; }
In this research I revealed evidence for two buried soils in the Aceh Province, Sumatra. I focused on the litho- and biostratigraphy of the lower buried soil, which is indicative of coseismic subsidence from a paleoearthquake estimated to have occurred ca. 6500-7000 years BP. Approximately 1-3 m above the lower buried soil sequence is an upper buried soil with an age of ca. 5500-6000 years BP. I used a multi-proxy method that included pollen, foraminifera, and the gastropod Cerithidea cingulata (Gmelin, 1791) to identify the lower buried soil, establish the preseismic and postseismic paleoenvironments, and estimate the amount of coseismic subsidence to be 0.4 ± 0.3 m.
Using our own distribution study and previous work, I determined the indicative meaning of C. cingulata in the modern environment. I then used this species as a sea-level indicator in the lower buried soil sequence to determine the elevation of the postseismic land surface and constrain the age of the paleoearthquake. I calibrated the 14C age of a C. cingulata shell in the postseismic unit of the lower soil by incorporating a species-specific regional correction (ΔR) to the marine reservoir effect. I developed the correction from 11 shells of known age collected prior to 1950 from sites across southeast Asia.
Hurricane Isabel deposited overwash sand on a back-barrier salt marsh of Ocracoke Island, North Carolina on September 18th 2003. Data collected annually between May 2004 and October 2010 showed changes in the elevation, geomorphology, and the ecological evolution of the overwash deposit. The results indicated that marsh foraminifera and plants did not recolonize until the surface of the overwash deposit was eroded to an elevation within the intertidal zone. Once this elevation was crossed, recolonization occurred in less than one year. The erosion of the overwash deposit suggests that the stratigraphic record of storm-driven overwash is likely not representative of the actual number of landfalling hurricanes in environments such as the Outer Banks of North Carolina
Kinetic separation of CO2 and CH4 on Carbon Molecular Sieves: Study of the internal diffusion and surface resistance of pure gases and binary gas mixtures Introduction and objectives
International audienceCarbon Molecular Sieves (CMS) adsorbents appear to be good candidates for gas kinetic separations by using Pressure Swing Adsorption (PSA) processes: their pore morphologies could imply diffusion rate variations depending on their nature and the size of the gas adsorbate. We studied the separation of CO2 and CH4 with a CMS material in PSA processes experimentally and by using the Linear Driving Force (LDF) theory. The results show a high kinetic selectivity for CO2. But there are lacks in the understanding of the involved diffusion phenomena. Thus, we propose to distinguish the different involved phenomena of diffusion by measuring the diffusion coefficients of CO2 and CH4 on the CMS using the Zero Length Column (ZLC) method [1]: this macroscopic method allows to separate the diffusion mechanisms by adjusting the gas velocities in the column containing the adsorbent material. The conclusion of these measurements is that the CH4 diffusion is only controlled by surface resistance diffusion whereas both internal and surface diffusion resistances are involved in CO2 diffusion as already showed by Liu and Ruthven on others CMS materials [2]. In addition of these evaluations, we propose to focus on the binary diffusion of CH4 and CO2 and then to study the influence on the kinetic selectivity of a residual adsorption of CO2 or CH4 on the CMS adsorbent when separating the CO2-CH4 mixture. The results of the binary diffusion rate measurements will be presented and qualitatively linked to the textural properties of the studied CMS
Garrett, R. PhD supporting data
Data submitted in part fulfillment of a PhD qualification from Bangor Universit
- …