937 resultados para Products
Resumo:
Fuel-only algal systems are not economically feasible because yields are too low and costs too high for producing microalgal biomass compared to using agricultural residues e.g. straw. Biorefineries which integrate biomass conversion processes and equipment to produce fuels, power and chemicals from biomass, offer a solution. The CO2 microalgae biorefinery (D-Factory) is a 10 million Euro FP7-funded project which will cultivate the microalga Dunaliella in highly saline non-potable waters in photobioreactors and open raceways and apply biorefinery concepts and European innovations in biomass processing technologies to develop a basket of compounds from Dunaliella biomass, including the high value nutraceutical, β-carotene, and glycerol. Glycerol now finds markets both as a green chemical intermediate and as a biofuel in CHP applications as a result of novel combustion technology. Driving down costs by recovering the entire biomass of Dunaliella cells from saline cultivation water poses one of the many challenges for the D-Factory because Dunaliella cells are both motile, and do not possess an external cell wall, making them highly susceptible to cell rupture. Controlling expression of desired metabolic pathways to deliver the desired portfolio of compounds flexibly and sustainably to meet market demand is another. The first prototype D-Factory in Europe will be operational in 48 months, and will serve as a robust manifestation of the business case for global investment in algae biorefineries and in large-scale production of microalgae.
Resumo:
Models and software products have been developed for modelling, simulation and prediction of different correlations in materials science, including 1. the correlation between processing parameters and properties in titanium alloys and ?-titanium aluminides; 2. time–temperature–transformation (TTT) diagrams for titanium alloys; 3. corrosion resistance of titanium alloys; 4. surface hardness and microhardness profile of nitrocarburised layers; 5. fatigue stress life (S–N) diagrams for Ti–6Al–4V alloys. The programs are based on trained artificial neural networks. For each particular case appropriate combination of inputs and outputs is chosen. Very good performances of the models are achieved. Graphical user interfaces (GUI) are created for easy use of the models. In addition interactive text versions are developed. The models designed are combined and integrated in software package that is built up on a modular fashion. The software products are available in versions for different platforms including Windows 95/98/2000/NT, UNIX and Apple Macintosh. Description of the software products is given, to demonstrate that they are convenient and powerful tools for practical applications in solving various problems in materials science. Examples for optimisation of the alloy compositions, processing parameters and working conditions are illustrated. An option for use of the software in materials selection procedure is described.
Resumo:
Treatment of guanosine or 2'-deoxyguanosine with dimethyldioxirane, followed by heating in aqueous solution, generates respectively 4-amidinocarbamoyl-5-hydroxyimidazole (1) or its 2-(2,3,4-trihydroxybutyl) derivative (2).
Resumo:
Advanced glycation end products (AGEs) have been implicated in the progressive vascular dysfunction which occurs during diabetic retinopathy. In the current study we have examined the role of these adducts in blood-retinal barrier (BRB) breakdown and investigated expression of the vasopermeabilizing agent vascular endothelial growth factor (VEGF) in the retina. When normoglycemic rats were injected with AGE-modified albumin daily for up to 10 days there was widespread leakage of FITC-dextran and serum albumin from the retinal vasculature when compared to control animals treated with nonmodified albumin. Ultrastructural examination of the vasculature revealed areas of attenuation of the retinal vascular endothelium and increased vesicular organelles only in the AGE-exposed rats. Quantitative RT-PCR and in situ hybridization demonstrated a significant increase in retinal VEGF mRNA expression (P <0.05). These results suggest that AGEs can initiate BRB dysfunction in nondiabetic rats and a concomitant increase in retinal VEGF expression. These findings may have implications for the role of AGEs in the pathogenesis of diabetic retinopathy.
Resumo:
We study properties of subspace lattices related to the continuity of the map Lat and the notion of reflexivity. We characterize various “closedness” properties in different ways and give the hierarchy between them. We investigate several properties related to tensor products of subspace lattices and show that the tensor product of the projection lattices of two von Neumann algebras, one of which is injective, is reflexive.
Resumo:
BACKGROUND: Diabetics have a significantly higher percentage of sperm with nuclear DNA (nDNA) fragmentation and increased levels of advanced glycation end products (AGEs), in their testis, epididymis and sperm. As the receptor for AGEs (RAGE) is important to oxidative stress and cell dysfunction, we hypothesise, that it may be involved in sperm nDNA damage. METHODS: Immunohistochemistry was performed to determine the presence of RAGE in the human testis and epididymis. A comparison of the receptor's incidence and localisation on sperm from 10 diabetic and 11 non-diabetic men was conducted by blind semi-quantitative assessment of the immunostaining. ELISA analysis ascertained RAGE levels in seminal plasma and sperm from 21 diabetic and 31 non-diabetic subjects. Dual labelling immunolocalisation was employed to evaluate RAGE's precise location on the sperm head. RESULTS: RAGE was found throughout the testis, caput epididymis, particularly the principle cells apical region, and on sperm acrosomes. The number of sperm displaying RAGE and the overall protein amount found in sperm and seminal plasma were significantly higher in samples from diabetic men (p
Resumo:
Suppression of angiogenesis during diabetes is a recognized phenomenon but is less appreciated within the context of diabetic retinopathy. The current study has investigated regulation of retinal angiogenesis by diabetic serum and determined if advanced glycation end products (AGEs) could modulate this response, possibly via AGE-receptor interactions. A novel in vitro model of retinal angiogenesis was developed and the ability of diabetic sera to regulate this process was quantified. AGE-modified serum albumin was prepared according to a range of protocols, and these were also analyzed along with neutralization of the AGE receptors galectin-3 and RAGE. Retinal ischemia and neovascularization were also studied in a murine model of oxygen-induced proliferative retinopathy (OIR) in wild-type and galectin-3 knockout mice (gal3(-/-)) after perfusion of preformed AGEs. Serum from nondiabetic patients showed significantly more angiogenic potential than diabetic serum (P <0.0001) and within the diabetic group, poor glycemic control resulted in more AGEs but less angiogenic potential than tight control (P <0.01). AGE-modified albumin caused a dose-dependent inhibition of angiogenesis (P <0.001), and AGE receptor neutralization significantly reversed the AGE-mediated suppression of angiogenesis (P <0.01). AGE-treated wild-type mice showed a significant increase in inner retinal ischemia and a reduction in neovascularization compared with non-AGE controls (P <0.001). However, ablation of galectin-3 abolished the AGE-mediated increase in retinal ischemia and restored the neovascular response to that seen in controls. The data suggest a significant suppression of angiogenesis by the retinal microvasculature during diabetes and implicate AGEs and AGE-receptor interactions in its causation.
Resumo:
PURPOSE: A critical event in the pathogenesis of diabetic retinopathy is the inappropriate adherence of leukocytes to the retinal capillaries. Advanced glycation end-products (AGEs) are known to play a role in chronic inflammatory processes, and the authors postulated that these adducts may play a role in promoting pathogenic increases in proinflammatory pathways within the retinal microvasculature. METHODS: Retinal microvascular endothelial cells (RMECs) were treated with glycoaldehyde-modified albumin (AGE-Alb) or unmodified albumin (Alb). NFkappaB DNA binding was measured by electromobility shift assay (EMSA) and quantified with an ELISA: In addition, the effect of AGEs on leukocyte adhesion to endothelial cell monolayers was investigated. Further studies were performed in an attempt to confirm that this was AGE-induced adhesion by co-incubation of AGE-treated cells with soluble receptor for AGE (sRAGE). Parallel in vivo studies of nondiabetic mice assessed the effect of intraperitoneal delivery of AGE-Alb on ICAM-1 mRNA expression, NFkappaB DNA-binding activity, leukostasis, and blood-retinal barrier breakdown. RESULTS: Treatment with AGE-Alb significantly enhanced the DNA-binding activity of NFkappaB (P = 0.0045) in retinal endothelial cells (RMECs) and increased the adhesion of leukocytes to RMEC monolayers (P = 0.04). The latter was significantly reduced by co-incubation with sRAGE (P <0.01). Mice infused with AGE-Alb demonstrated a 1.8-fold increase in ICAM-1 mRNA when compared with control animals (P <0.001, n = 20) as early as 48 hours, and this response remained for 7 days of treatment. Quantification of retinal NFkappaB demonstrated a threefold increase with AGE-Alb infusion in comparison to control levels (AGE Alb versus Alb, 0.23 vs. 0.076, P <0.001, n = 10 mice). AGE-Alb treatment of mice also caused a significant increase in leukostasis in the retina (AGE-Alb versus Alb, 6.89 vs. 2.53, n = 12, P <0.05) and a statistically significant increase in breakdown of the blood-retinal barrier (AGE Alb versus Alb, 8.2 vs. 1.6 n = 10, P <0.001). CONCLUSIONS: AGEs caused upregulation of NFkappaB in the retinal microvascular endothelium and an AGE-specific increase in leukocyte adhesion in vitro was also observed. In addition, increased leukocyte adherence in vivo was demonstrated that was accompanied by blood-retinal barrier dysfunction. These findings add further evidence to the thinking that AGEs may play an important role in the pathogenesis of diabetic retinopathy.