Background: Acid test meals may improve the accuracy of the C urea breath test (UBT). This has been attributed to changes in gastric emptying rather than to the effects of gastric pH on Helicobacter pylori urease. Aims: To determine whether enhancement of CO2 excretion in the UBT in H pylori infected volunteers by acidification of a test meal is due to a delay in gastric emptying. Methods: Urea...

TEM and XRD techniques were used to study crystal growth characteristics of the fabric-forming phyllosilicates which developed in response to low-grade metamorphism and tectonic imbrication in part of the Southern Uplands thrust terrane. Prograde regional metamorphism, ranging from late diagenesis through the anchizone to the epizone, was accompanied by the development of a slaty cleavage which...

-New and published experimental data on hydrothermally treated (2-kbar water pressure, 300-400~ natural clay minerals is used to construct phase diagrams in composition and pressure-temperature space which define the phase relations of mixed layering solid solution in dioctahedral (illitemontmorillonite) and trioctahedral expanding chlorite and corrensite-like minerals. Three major relations ar...

Chlorite dismutases (Clds) convert chlorite to O2 and Cl(-), stabilizing heme in the presence of strong oxidants and forming the O═O bond with high efficiency. The enzyme from the pathogen Klebsiella pneumoniae (KpCld) represents a subfamily of Clds that share most of their active site structure with efficient O2-producing Clds, even though they have a truncated monomeric structure, exist as a ...

chlorite flakes, as a product of alteration of biotite, the dominant ferromagnesian mineral in the paleozoic granitic rocks of the canadian appalachians, have been analyzed by electron microprobe for major elements and by 57fe m?ssbauer spectroscopy for the coordination and oxidation state of fe. comparison of m?ssbauer fe3+/fe ratios obtained from chlorite and its host biotite indicates that c...

-Chlorite-mica stacks (grains of intergrown chlorite and white mica) in a matrix of fine-grained white mica and chlorite have been studied using XRD, SEM, EMPA, TEM and AEM methods. The stacks occur in a weakly cleaved Llandoverian mudstone, central Wales, which has a white mica (illite) crystallinity index of 0.35 ° A20 corresponding to the lower anchizone. White mica occurs as packets (100/~ ...

The chemical and structural organization of the plant cell wall was examined in Zinnia elegans tracheary elements (TEs), which specialize by developing prominent secondary wall thickenings underlying the primary wall during xylogenesis in vitro. Three imaging platforms were used in conjunction with chemical extraction of wall components to investigate the composition and structure of single Zin...