Search results for "Oxide"
showing 10 items of 6424 documents
Degradation of phosphatidylethanol counteracts the apparent phospholipase D-mediated formation in heart and other organs.
2003
Phosphatidylalcohols, such as phosphatidylethanol (PEth), are formed from phosphatidylcholine in the presence of a primary alcohol (e.g., ethanol). This 'transphosphatidylation' reaction is used as specific phospholipase D (PLD) assay. Accumulation of PEth in tissues is recognized as a reliable measure of PLD activity, as PEth is allegedly metabolically stable. The general validity of this assumption was reinvestigated in isolated rat heart, small intestine and brain slices. The half-times of 3H-PEth degradation (labelled with 3H-myristic acid and preformed by ethanol exposure for 30 min) were about 1 h in heart and small intestine, but 17 h in brain. As the formation of PEth is superimpose…
In vitro effectiveness of different endodontic irrigants on the reduction of Enterococcus faecalis in root canals
2010
Objective: To compare the reduction of E. faecalis counts in root canals produced by irrigation with distilled water, hydrogen peroxide, sodium hypochlorite, chlorhexidine, and combinations of solutions, in vitro. Study Design: Study sample included sixty mandibular premolar teeth mounted in dental stone. Root canals were prepared using crown down technique under distilled water irrigation. Specimens were sterilized overnight by ethylene oxide gas. Each canal was completely filled up with the E. faecalis suspension and incubated at 37ºC for 24 hours. Root canals were irrigated with the test solutions. A volume of 5 ml of the tested irrigant was used for each sample with an exposure period o…
European Sea Bass (Dicentrarchus labrax) immune status and disease resistance are impaired by arginine dietary supplementation
2015
Infectious diseases and fish feeds management are probably the major expenses in the aquaculture business. Hence, it is a priority to define sustainable strategies which simultaneously avoid therapeutic procedures and reinforce fish immunity. Currently, one preferred approach is the use of immunostimulants which can be supplemented to the fish diets. Arginine is a versatile amino acid with important mechanisms closely related to the immune response. Aiming at finding out how arginine affects the innate immune status or improve disease resistance of European seabass (Dicentrarchus labrax) against vibriosis, fish were fed two arginine-supplemented diets (1% and 2% arginine supplementation). A…
Multilayered supported ionic liquids as catalysts for chemical fixation of carbon dioxide
2011
Multilayered, covalently supported ionic liquid phase (mlc-SILP) materials were synthesized by using a new approach based on the grafting of bis-vinylimidazolium salts on different types of silica or polymeric supports. The obtained materials were characterized and tested as catalysts in the reaction of supercritical carbon dioxide with various epoxides to produce cyclic carbonates. The material prepared by supporting a bromide bis-imidazolium salt on the ordered mesoporous silica SBA-15 was identified as the most active catalyst for the synthesis of cyclic carbonates and displayed improved productivity compared with known supported ionic liquid catalysts. The catalyst retained its high act…
Performance of Sulfonated Poly(Vinyl Alcohol)/Graphene Oxide Polyelectrolytes for Direct Methanol Fuel Cells
2020
The use of nanotechnology along with the consideration of a functionalization and stabilization approach to poly(vinyl alcohol) (PVA) is considered useful for the preparation of cost-effective polyelectrolyte membranes. A set of nanocomposite and crosslinked membranes based on PVA/sulfosuccinic acid (SSA)/graphene oxide (GO) are prepared and analyzed as polyelectrolytes in direct methanol fuel cells (DMFCs). The crosslinking and sulfonation by the use of SSA enhances the stability and increase the proton-conducting sites in the PVA structure. The presence of GO augments the stability, remarkably decreases the methanol crossover, and enhances power density curves. An optimum value for proton…
Fibrous Nanozyme Dressings with Catalase-Like Activity for H2O2 Reduction To Promote Wound Healing
2017
The concentrations of the redox pair hydrogen peroxide (H2O2) and oxygen (O2) can promote or decelerate the progression and duration of the wound healing process. Although H2O2 can reach critically high concentrations and prohibit healing, a sufficient O2 inflow to the wound is commonly desired. Herein, we describe the fabrication and use of a membrane that can contemptuously decrease H2O2 and increase O2 levels. Therefore, hematite nanozyme particles were integrated into electrospun and cross-linked poly(vinyl alcohol) membranes. Within the dual-compound membrane, the polymeric mesh provides a porous scaffold with high water permeability and the nanozymes act as a catalyst with catalase-li…
Functionalised poly (vinyl alcohol)/graphene oxide as polymer composite electrolyte membranes
2019
[EN] Crosslinked poly(vinyl alcohol) (PVA) based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells (DEFC). The membranes were functionalised by means of the addition of graphene oxide (GO) and sulfonated graphene oxide (SGO) and crosslinked with sulfosuccinic acid (SSA). The chemical structure was corroborated and suitable thermal properties were found. Although the addition of GO and SGO slightly decreased the proton conductivity of the membranes, a significant reduction of the ethanol solution swelling and crossover was encountered, more relevant for those functionalised with SGO. In general, the composite membranes were stable under …
July 2003: 62-year-old female with progressive muscular weakness
2004
The July 2003 Case of the Month (COM). A 62-year-old female patient experienced progressive muscular weakness over the last ten years, involving shoulder and pelvic girdle muscles, paraspinal and facial muscles. A biopsy was taken from the left deltoid muscle where hepatitis vaccination had taken place 4 weeks previously. The specimen revealed macrophagic myofasciitis due to the injection of aluminium-bound vaccines. The finding can be reproduced experimentally by injecting vaccines in rats. The pathomechanism is supposed to involve immune stimulation due to long term persistence of the adjuvant. Macrophagic myofasciitis has been suggested to occasionally cause myopathy but is supposed to b…
Visible light active self-cleaning materials based on porphyrin-sensitised titanium dioxide
2017
Starting from second half of last century, nanostructured semiconductors have had a crucial function in the material science because of their wide application field going from renewable energy to organic/hybrid electronics up to photocatalysis. Among those materials, titanium dioxide is probably the most used because of some important characteristics like the chemical/mechanical stability, environmental sustainability, its low cost and versatility. Indeed, it has been successfully employed as photo- and electro-active component in electronic devices as well as photocatalytic agent1 in water de-pollution application. Interestingly and importantly together, titanium dioxide may also be applie…
Stability of the lipid fraction of milk‐based infant formulas during storage
2005
A study is made of the effects of storage (time and temperature) on the lipid fraction of four milk-based adapted infant formulas with basically the same composition, though differing in the iron salt added (lactate or sulfate) and/or the vitamin E source (a-tocopherol or α-tocopherol acetate). Peroxide value, hydroperoxide C 18 percentage and thiobarbituric acid-reactive substance (TBARS) content were used as indicators of lipid peroxidation. Fat contents remained stable throughout storage. Peroxide values increased from the first storage month and were affected by storage time, although they exhibited irregular behavior. Storage time and temperature affected hydroperoxide percentage, whic…