In this study, we use the bacterium Escherichia coli to examine evolutionary responses to environmental acidity fluctuating temporally among pH 5.3, 6.3, 7.0, and 7.8 (5,000-15 nM [H(+)]). Two experimental protocols of temporal variation were used. One group (six replicate lines) of populations evolved for 2,000 generations during exposure to a cycled regime fluctuating daily between pH 5.3 and...

BACKGROUND Until now there has been no study that directly compares the effect of lansoprazole and pantoprazole administered intravenously on intragastric acidity. The aim of this study is to compare the effect of lansoprazole (30 mg) and pantoprazole (40 mg) administered intravenously on gastric acidity. MATERIAL/METHODS Helicobacter pylori-negative healthy volunteers were recruited in this ...

BACKGROUND/AIMS The sensitivity of the upper and lower esophageal mucosa to acid is considered to differ. We investigated the relationship between pH changes in different sites of the esophagus and generation of gastroesophageal reflux symptoms during an acid infusion test. METHODS An acid infusion catheter was placed at 5 or 15 cm above the lower esophageal sphincter (LES) in 18 healthy volu...

This study examines whether eating food at different times has differential effects on intragastric pH. Experiments were done in 23 healthy volunteers (12 men). Intragastric acidity was monitored by ambulatory 22 hour pH-metry. Composition of meals was standardised: breakfast and lunch at 7 am and 12 noon respectively, and dinner at 6 or 9 pm, in random order. The time of going to bed and getti...

In soils of tropical climate regions the high acidity and the presence of exchangeable aluminum (Al), associated to low fertility, are the main restrainting factors for agricultural production. A laboratory experiment was conducted using 26 soils of different Brazilian regions, to investigate soil acidity components, giving emphasis to Al and their relations with chemical properties. The pH cor...

Acidity is one of the main determinants taste and quality melon fruit, together with sugars volatilecompounds. The aim this study was to investigate inheritance hydrogen potential (pH) titratable acidity in fruit.A randomized block design three replications used evaluate F1and F2generations backcrosses (RC1and RC2) ofthe Védrantais (Cucumis melo subsp. var. reticulatus) high pH low acidity, AC-...

BACKGROUND A Stanford University study reported that in asymptomatic GERD patients who were being treated with a proton pump inhibitor (PPI), 50% had pathologic esophageal acid exposure. AIM We considered the possibility that the high prevalence of pathologic esophageal reflux might simply have resulted from calculating acidity as time pH < 4. METHODS We calculated integrated acidity and ti...