Due to the rise in global biodiesel production, the amount of crude glycerol, the main byproduct, has increased steadily. Identification of high value addedoutlets for crude glycerol has been explored in detail to increase the overall economics of the biodiesel process. Examples are the use of glycerol for the synthesis of green biobased chemicals and the conversion to hydrogen and/or syngas. Supercritical water has received considerable attention as reaction medium for glycerol reforming because it allows the processing of streams with high moisture content and the production of clean gas at high pressure, being attractive from an environmental point of view. The recent interest in supercritical water reforming of biomass, especially glycerol, hascreated the need for the available data in this specific field to be collected and compared. This review, the first to deal exclusively with glycerol processing, focuses on the production of gas and of organic components in supercritical water. Both catalytic and non-catalytic reforming of glycerol is considered and thermodynamics are addressed. The results suggest that the process conditions during supercritical water reforming of glycerol should depend on the aimed products. Low temperatures, high pressures, concentrated feed solutions and acidic catalyst will generate liquid products, with acrolein as the main compound. For gasification, high temperatures, lower pressures, dilute feed solutions and alkali or metal catalysts should be used.
High pressure technologies involving sub and supercritical fluids offer the possibility to obtain new products with special characteristics or to design new processes, which are environmentally friendly and sustainable. By using high pressure as a processing tool one can also avoid the legal limitations for solvent residues and restrictions on use of conventional solvents in chemical processes. Supercritical fluids are already applied in several processes developed to commercial scale in pharmaceutical, food and textile industries. Extraction of valuable compounds from plant materials and their "in situ" formulation in products with specific properties is one of the very promising applications of high pressure technology. Particle formation using supercritical fluids may overcome the drawbacks of conventional particle size reduction processes. Because of their unique thermo-dynamic and fluid-dynamic properties, dense gases can also be used for impregnation of solid particles, particle coating, foaming etc. Some biochemical and chemical reactions performed in supercritical fluids have already been implemented at industrial scale to obtain products with high added value, while the use of supercritical fluids as heat carriers is a newly emerging field. In our short overview we present some applications and future expected development in the field of sub and supercritical fluids.
Ganoderma lucidum has been used in oriental medicine for its contribution to vitality and longevity. None of them report about targeted antitumor activity against adenocarcinoma cells, or antioxidant and antiacetylcholinesterase activity for potential application in treatment of Alzheimer's and other neurodegenerative diseases. To date, there are a few studies available concerning supercritical carbon dioxide extraction of biologically active compounds from G. lucidum fruiting body. In our study, two stage extractions of biologically active compounds from G. lucidum were performed. First, supercritical carbon dioxide was used as extraction solvent. Next, the same material was used for hot water isolation of biologically active polysaccharides. Cytotoxicity, antioxidant and antiacetylcholinesterase activity were tested for all obtained extracts. Additionally, the effect of extraction process conditions on the biological activity of extracts was assessed.
Polyphenol antioxidants decrease the risk of atherosclerosis. The study aimed to evaluate prospectively in healthy young participants the effect of oral rosemary extracts (RE), consisting of diphenols, upon endothelial dysfunction (ED), preceding structural atherosclerosis. Nineteen healthy young volunteers were studied prospectively, who received oral RE (77.7 mg) for 21 days, consisting of active substances carnosol (0.97 mg), carnosic (8.60 mg) and rosmarinic acid (10.30 mg). Before and after RE treatment, the study evaluated fasting serum levels of plasminogen-activator-inhibitor-1 (PAI-1), vascular cell adhesion molecule 1 (VCAM-1), inter-cellular adhesion molecule 1 (ICAM-1), superoxide dismutase (SOD), glutathione peroxidase (GPX), fibrinogen, high-sensitivity capsular reactive protein (hs-CRP), tumor-necrosis factor alpha (TNF-alpha), the lipid profile and ED, characterized as flow-mediated dilatation (FMD) in the brachial artery of ( 4.5%, estimated by ultrasound measurements. After 21 days, any side effects were registered, the mean FMD increased nonsignificantly (6.51 +/- 5.96% vs 7.78 +/- 4.56%, p = 0.546) and ED decreased significantly (66.6% vs 16.6%, p = 0.040). Among the serum markers, only the mean PAI-1 level decreased significantly (4.25 +/- 1.46 U/mL vs 3.0 +/- 0.61 U/mL, p = 0.012) after 21-day RE supplementation. It is concluded that oral RE supplementation has the potential to improve serum PAI-1 activity and ED in young and healthy individuals.
Water-scale precipitation was observed on electrical heaters within boilers for hot water preparation within households. Different permanent magnetic devices and electromagnetic device were installed on the inlet pipe in the boiler. The system was supplied with tap water of known chemical composition. The magnetic water treatment took place over several days under constant conditions (temperature in the boiler, water composition, etc.) along two parallel lines. The first one was the treated line and the second was for comparison. This paper presents the experimentally confirmed results using different permanent magnets and electromagnets for reducing the amount of precipitated water-scale on heaters for hot water. The impacts of different operational conditions are presented regarding the devices' effectiveness. Scale samples were analysed by X-ray diffraction, where it was discovered that all the samples were in the shapes of aragonite.