Adapting Modern ICTs to the Spatial and Cultural Environment of Urban Africa : The Experience of Cameroon

Navigation-facilitating information and communication technologies, especially personal navigation devices (PNDs), are commonplace, and account for a significant share of the GDP, in developed countries. However, their utility is compromised in Africa where the precise and unambiguous physical addresses necessary for their functioning are a rarity. This paper proposes a strategy that can significantly improve the functioning of these devices despite the lack of precise and unambiguous physical addresses. The strategy incorporates major aspects of African indigenous culture and tradition blended with received cultural practices. Cameroon serves as the empirical referent. The paper identifies specific benefits of facilitating geospatial navigation including economic value of journey time savings, environmental protection via reduced carbon emissions, cost savings resulting from reduced fuel consumption, and improved efficiency for entities involved in door-to-door service/goods delivery

Pharmacokinetic characterization of phosphatidylserine liposomes in the rat

1. The plasma decay, tissue uptake and biotransformation of radiolabelled phosphatidylserine (PS) liposomes have been investigated in rats following bolus i.v. injection (2 mg kg-1). 2. PS plasma concentration showed a biexponential decay with half-lives of 0.85 and 40 min. The following interpretation of the biphasic decay is proposed: (1) The rapid initial decline is due to the irreversible uptake of PS liposomes by the mononuclear phagocyte system, as demonstrated by the almost exclusive accumulation of PS in liver and spleen. (2) The slow decay phase reflects the elimination of that fraction of PS that has been incorporated into high density plasma lipoproteins (HDL). A kinetic model has been developed to describe these phenomena and a good agreement has been observed between experimental data and theoretical values. 3. Evidence has been obtained that a large fraction of PS is hydrolyzed at the injection site, probably by phospholipase A2 and other hydrolytic enzymes released by platelets. Hydrolysis at the injection site has also been observed following intraperitoneal and intramuscular injections. 4. As shown by the comparative analysis of the biotransformation products found in tissues after administration of either [3H]-glycerol-PS or [14C]-serine-PS, parenterally administered PS follows two distinct metabolic pathways: (1) decarboxylation to phosphatidylethanolamine and (2) extensive hydrolytic degradation with release of the individual components of the molecule. These pathways probably reflect the two main mechanisms of PS uptake, incorporation into the plasma membrane and internalization by endocytosis, respectively

Encapsulation of N,N-diethyl-meta-toluamide (DEET) via miniemulsion polymerization for temperature controlled release

N,N-diethyl-meta-toluamide (DEET), an insect repellent, can be successfully encapsulated in poly(n-butyl methacrylate-co-methyl methacrylate) nanospheres via direct miniemulsion polymerization. Stable and low polydisperse nanospheres with a number average diameter of 114 +/- 37nm were obtained. It is shown that DEET is an effective costabilizer and that sodium lauryl sulfate is a suitable surfactant. The nanospheres glass-transition temperature (T-g) can be tuned by adjusting the ratio between n-butyl methacrylate and methyl methacrylate in the monomer formulation. The repellent reduced the polymerization reaction rate and the copolymer molecular weight, and changed the nanoparticle morphology. The release rate of the encapsulated DEET provides repellency for over 9 h and is and more controlled when compared to the free DEET. Results show the mechanism of release is temperature dependent. At temperatures close to and lower than the polymer T-g, polymer relaxation is the limiting mechanism. At higher temperatures, Fickian diffusion limits the overall release. Thus, the DEET release rate can be tuned by adjusting the copolymer T-g. This ensures this material a great potential as temperature-dependent delivery system1369FAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo2016/13427‐

Prevention of postsurgical adhesions with an autocrosslinked hyaluronan derivative gel

Abstract BACKGROUND: ACP gel is a new crosslinked derivative of hyaluronic acid (HA) that displays the biocompatibility properties of its original polymer but has a higher viscosity. It has been demonstrated in an animal model that the gel reduces adhesions after gynecological surgery. The aim of the present study was therefore to investigate the efficacy of ACP gel in increasing viscosity for the prevention of adhesions after abdominal surgery. METHODS: The antiadhesive effect of ACP gel was tested in a controlled randomized study using a standardized animal model of abdominal surgery involving the creation of defects in the parietal peritoneum and muscular fascia and cecal abrasion. The animals (100 female New Zealand white rabbits) were randomly allocated into five treatment groups to receive: ACP gel (1, 2, 4, and 6%) on the injured area or no ACP gel (control). The incidence of adhesions and their grade (score 0-11) were blindly evaluated 10 weeks after surgery. RESULTS: The percentages of adhesion-free animals were 60, 84, 90, and 84% in the 1, 2, 4, and 6% ACP gel concentration groups, respectively, versus 15% in the control group (P = 0.001). The mean adhesion scores were 3.00 +/- 0.91, 1.37 +/- 0.75, 0.65 +/- 0.45, and 1.16 +/- 0.64 in the 1, 2, 4, and 6% ACP gel groups, respectively, versus 7.70 +/- 0.83 in the control group (P < 0.001). CONCLUSION: ACP gel prevents postsurgical abdominal adhesions even at a 1% concentration. This finding may be of clinical importance in situations in which large volumes of antiadhesive solution are required. Copyright 2001 Academic Press