Search results for "Hydrogen"

An Approach on the Hydrogen Absorption in Carbon Black after Gamma Irradiation

2013

In this work, different samples of an industrial carbon black are used to study the hydrogen intake from an over pres-surized atmosphere and its changes due to alteration of its level of crystallinity produced by ¿-irradiation. The monitor-ing of the hydrogen adsorption was made by means of thermogravimetric analysis and by measurements of some elec-trical parameters as the Seebeck coefficient. X-ray diffraction shows that the irradiation diminishes the level of crystal-line perfection. These results show interesting possibilities to use carbon black as cheap hydrogen absorbers.

Estimation of hydrogen transfer mechanisms in composite materials

2008

Abstract Spill-over effect as a hydrogen transfer mechanism is proposed to explain an increased capacity of hydrogen absorption and improvement of hydrogen activation kinetics in composite material based on the AB5 type metal hydride and powdered glass. A raw lanthanum nickel alloy AB5 with small amount of additives was used as catalyst and bulk material for hydrogen storage, and a borosilicate glass powder with developed surface was applied as a support material. Thermogravimetric technique to determine an absorbed amount of the hydrogen in materials and X-ray powder diffraction analysis for structural investigations was used.

Preparation and Characterisation of Alendronate-Loaded Chitosan Microparticles Obtained Through the Spray Drying Technique

2009

Microparticles of chitosan (CHT) containing alendronate sodium (AL) were prepared in four drug:polymer ratios (1:1, 1:2, 1:4, 1:6) using the spray drying technique. The efficiency of the method was evaluated by determining production yield (about 70 %) and microencapsulation efficiency, which was almost 100 % in the case of all four of the formulations studied. Particles had a mean size of between 3.6 and 4.6 microm, and a near-spherical shape. The formulations with the highest content of AL (drug:polymer ratio 1:1 and 1:2) showed an asymmetrical distribution of particles, which were larger in size, and had a higher proportion of irregular particles than the other formulations. FT-IR analys…

Polycatenane systems from Co(II) and trans-1,2-bis(4-pyridyl)ethene (bpe). Synthesis and structure of Co(bpe)2(NCS)2·CH3OH, [Co(bpe)2(H2O)2](ClO4)2·2…

2001

Three new compounds of formulae Co(bpe)2(NCS)2·CH3OH, 1, [Co(bpe)2(H2O)2](ClO4)2·2CH3OH, 2 and [Co(bpe)2(H2O)2(CH3OH)2](ClO4)2·bpe·H2O, 3, [bpe =  trans-1,2-bis(4-pyridyl)ethene] have been synthesised and characterised by single crystal X-ray diffraction. The metal environment in 1–3 is distorted octahedral. Compound 1 is a polycatenane. Its structure consists of parallel layers containing Co2+ ions linked by bpe ligands, the Co···Co distance through the bpe bridge being 13.65(3) A. Each metal ion, in a layer, defines the edges of a rhombus. Two thiocyanate groups trans-coordinated to the metal atoms are perpendicular to the sheets. Each sheet has an infinite number of perpendicular sheets …

Supramolecular diversity and magnetic properties of novel heterometallic Cu(II)/Cr(III) complexes prepared from copper powder, Reineckes salt and eth…

2009

Abstract Three novel heterometallic complexes [Cu(en) 2 Cr(NCS) 4 (NH 3 ) 2 ][Cr(NCS) 4 (NH 3 ) 2 ] · 6dmf ( 1 ), [Cu(en) 2 Cr(NCS) 4 (NH 3 ) 2 ](OAc) ( 2 ) and [{Cu(en) 2 } 3 {Cr(NCS) 4 (NH 3 ) 2 } 2 (NCS) 2 ](NCS) 2 ( 3 ) have been synthesized in a one-pot reaction from copper powder, Reineckes salt, NH 4 X [X −  = OAc − ( 2 ), NCS − ( 3 )] in a dmf ( 1 ) or CH 3 CN ( 2 , 3 ) solution of ethylenediamine (en). X-ray studies showed that 1 and 2 consist of cationic polymeric chains, formed by Cu ( en ) 2 2 + and Cr ( NCS ) 4 ( NH 3 ) 2 - building blocks that bridged through thiocyanate anions. In both complexes, distinct hydrogen bonds are present and serve to increase the dimensionality of …

The Influence of Thiol Reagents on the Isoenzyme Pattern of Plant L+Lactate Dehydrogenase (EC 1.1.1.27)

1978

Summary Lactate dehydrogenase from potato tubers was incubated together with various thiol reagents and the effect on the electrophoretic behavior of its isoenzymes studied. while disulfides, alkylating agents, and H202 did not alter the number and electrophoretic behavior of the isoenzymes of L + LDH, reduced glutathione and 2-mercaptoethanol led to an increase in the number of isoenzymes. The reaction was dependent on concentration and pH. On the other hand, cysteine and cysteamine had no such effect. Results are discussed in view of the possible secondary nature of the plant LDH isoenzymes.

Regulation of Human Mitochondrial Aldehyde Dehydrogenase (ALDH-2) Activity by Electrophiles in Vitro

2011

Recently, mitochondrial aldehyde dehydrogenase (ALDH-2) was reported to reduce ischemic damage in an experimental myocardial infarction model. ALDH-2 activity is redox-sensitive. Therefore, we here compared effects of various electrophiles (organic nitrates, reactive fatty acid metabolites, or oxidants) on the activity of ALDH-2 with special emphasis on organic nitrate-induced inactivation of the enzyme, the biochemical correlate of nitrate tolerance. Recombinant human ALDH-2 was overexpressed in Escherichia coli; activity was determined with an HPLC-based assay, and reactive oxygen and nitrogen species formation was determined by chemiluminescence, fluorescence, protein tyrosine nitration,…

Effect of the TiO2 crystalline structure on the photocatalytic production of hydrogen

2010

Aβ Oligomers and Fibrillar Aggregates Induce Different Apoptotic Pathways in LAN5 Neuroblastoma Cell Cultures

2009

Fibril deposit formation of amyloid beta-protein (Abeta) in the brain is a hallmark of Alzheimer's disease (AD). Increasing evidence suggests that toxicity is linked to diffusible Abeta oligomers, which have been found in soluble brain extracts of AD patients, rather than to insoluble fibers. Here we report a study of the toxicity of two distinct forms of recombinant Abeta small oligomers and fibrillar aggregates to simulate the action of diffusible Abeta oligomers and amyloid plaques on neuronal cells. Different techniques, including dynamic light scattering, fluorescence, and scanning electron microscopy, have been used to characterize the two forms of Abeta. Under similar conditions and …

Potential Application of Voltammetry of Microparticles for Dating Porcine Blood-based Binding Media used in Taiwanese Architectural Polychromies

2012

A method for dating Hemoglobine-containing archaeological samples using the voltammetry of microparticles is described. This is based on the record of the voltammetric response of such materials attached to paraffin-impregnated graphite electrodes in contact with aqueous acetate buffer. Signals attributable to the Fe(III)/Fe(II) iron couple and their catalytic enhancement in the presence of H(2)O(2) can be correlated, via first-order reaction kinetics, with the time of aging of the samples. The method has been applied to the study and dating of the polychromed architectural decoration of different parts of the architectural complex of the Longshan Temple in Lukang (18(th)  century, Taiwan).