Search results for "Hydrogen"
showing 10 items of 4254 documents
Biogas Pollution and Mineral Deposits Formed on the Elements of Landfill Gas Engines
2022
Municipal landfills generate a significant amount of high-energy biogas, which can be used as a renewable gaseous fuel. However, it is necessary to improve the quality of this biogas due to the presence of various chemical compounds. The most common pollutants in landfill biogas include volatile compounds of silicon, sulphur, phosphorus and chlorine. The aforementioned elements, as well as other metals, were found both in the deposits and in the engine oil. The paper presents detailed characteristics of the solid residues formed in selected parts of gas engines powered by landfill biogas. Its elemental composition and morphology were investigated in order to determine the structure and infl…
Reconfigurable DNA Origami Nanocapsule for pH-Controlled Encapsulation and Display of Cargo
2019
DNA nanotechnology provides a toolbox for creating custom and precise nanostructures with nanometer-level accuracy. These nano-objects are often static by nature and serve as versatile templates for assembling various molecular components in a user-defined way. In addition to the static structures, the intrinsic programmability of DNA nanostructures allows the design of dynamic devices that can perform predefined tasks when triggered with external stimuli, such as drug delivery vehicles whose cargo display or release can be triggered with a specified physical or chemical cue in the biological environment. Here, we present a DNA origami nanocapsule that can be loaded with cargo and reversibl…
In vivo evaluation of the effects of 10% carbamide peroxide and 3.5% hydrogen peroxide on the enamel surface
2007
Objectives: Bleaching of vital teeth performed at home by the patient under the dentist’s supervision, using low-concentration peroxides and custom-fitted trays specifically designed for this purpose, is one of several options for this type of dental treatment, whether alone or in combination with another in-office bleaching technique. The objective of this study is to analyse the effect on the enamel surface of two bleaching products recommended for this technique. Materials & methods: Two bleaching products were used: VivaStyle (Vivadent), a 10% carbamide peroxide, and FKD (Kin), a 3.5% hydrogen peroxide. They were applied in trays to the anterior teeth of 20 patients (10 in each group). …
Small molecule modulators of amine oxidation, nuclear receptor signaling and glucuronidation : 3-phenylcoumarin as a scaffold of interest
2018
The costs of the drug development process are moderated as computer-aided drug design methods are able to expedite the steps required for lead identification. In fact, computational tools are nowadays virtually indispensable from target identification and validation to preclinical tests due to exponential growth of available information regarding both potential targets and small molecules. One such small molecule with growing number of variations is coumarin. Coumarin scaffold and its various derivatives continue to interest researchers for their vast application potential. Since naturally occurring coumarins are known for example for their antioxidant and anti-inflammatory properties, thos…
Flexible Perfluoropolyethers-Functionalized CNTs-Based UHMWPE Composites: A Study on Hydrogen Evolution, Conductivity and Thermal Stability
2022
Flexible conductive composites based on ultra-high molecular weight polyethylene (UHMWPE) filled with multi-walled carbon nanotubes (CNTs) modified by perfluoropolyethers (PFPEs) were produced. The bonding of PFPE chains, added in 1:1 and 2:1 weight ratios, on CNTs influences the dispersion of nanotubes in the UHMWPE matrix due to the non-polar nature of the polymer, facilitating the formation of nanofillers-rich conductive pathways and improving composites’ electrical conductivity (two to five orders of magnitude more) in comparison to UHMWPE-based nanocomposites obtained with pristine CNTs. Electrochemical atomic force microscopy (EC-AFM) was used to evaluate the morphological changes dur…
Hydrogen activation with perfluorinated organoboranes: 1,2,3- tris(pentafluorophenyl)-4,5,6,7-tetrafluoro-1-boraindene
2014
The perfluorinated boraindene 3 was synthesized and fully characterized. Both computational and crystallographic data show that 3 is antiaromatic. Compound 3 was shown to react reversibly with H2 and to catalyse the hydrogenation of cyclohexene. The mechanism of catalysis was probed experimentally and computationally. peerReviewed
Intrinsic fluorescence in non-aromatic peptide structures is induced by collective vibrations, charge reorganisation and short hydrogen bonds, as sho…
2020
Abstract Disentangling the origin of the optical activity of non-aromatic proteins is challenging due to their size and thus their high computational requisites. Here we show, in a much smaller model system, that the single amino acid glutamine undergoes a chemical transformation leading to an unreported glutamine-like structure which has a similar broad absorption spectrum reported previously for non-aromatic proteins. We further show computationally that the optical activity of the glutamine-like structure is directly coupled to short-hydrogen bonds, but also displays charge and vibrational fluctuations, the latter of which are also present in less optically active structures such as in L…
Effects of cyclic fatty acid monomers on the function of cultured rat cardiac myocytes in normoxia and hypoxia
1992
Abstract It was shown in a previous study that rat ventricular myocytes in culture do incorporate in their phospholipids the cyclic fatty acid monomers (CFAM), produced from linolenic acid by heating linseed oil. In the present study, the functional consequences of this incorporation were investigated. As compared to control cells, CFAM containing cells displayed altered electromechanical properties evidenced by decreased maximal diastolic potential, upstroke velocity and rate and a shortened action potential duration. Moreover, oxygen depletion exerted much more adverse effects on CFAM-treated cells than in control cells, such as spontaneous rhythm abnormalities, cell shortening failure an…
Effect of oxidoreduction potential and of gas bubbling on rheological properties and microstructure of acid skim milk gels acidified with glucono-del…
2009
Milk oxidoreduction potential was modified using gases during the production of a model dairy product and its effect on gel setting was studied. Acidification by glucono-delta-lactone was used to examine the physicochemistry of gelation and to avoid variations due to microorganisms sensitive to oxidoreduction potential. Four conditions of oxidoreduction potential were applied to milk: milk was gassed with air, nongassed, gassed with N(2), or gassed with N(2)H(2). The rheological properties and microstructure of these gels were determined using viscoelasticimetry, measurement of whey separation, and confocal laser scanning microscopy. It appeared that a reducing environment led to less-aggre…
Influence of low methoxyl pectin gel textures and in vitro release of rutin from calcium pectinate beads.
2013
This study described the preparation and characterization of low methoxyl pectin (LMP) gels and beads for controlled release applications. The rheological characterization of the various formulations was proposed. Then the mechanical and morphological characterizations of beads were determined. Finally, the controlled release studies taking rutin as a model drug was evaluated. The results showed that Young's modulus values of non-amidated LMP gels decrease when adding up to 15% sorbitol. Calcium pectinate beads loaded with rutin are about 600 μm, oblong shaped with dense matrix. Beads containing sodium bicarbonate showed about 80% lower rutin encapsulation efficiency by increasing the pH of…