Search results for "Acidity"
showing 10 items of 35 documents
Phytoplankton in extreme environments: importance and consequences of habitat permanency
2020
AbstractThere is hardly any sunshine exposed surface on this Earth, be it water or terrain, which would not support some biota. Still, many habitats offer harsh conditions requiring specialized physiological adaptations to survive. These environments are referred to as extremes; often inhabited by extremophilic organisms. In this review, characteristic species and assemblage properties of phytoplankton inhabiting extreme environments (especially lakes and pools where planktic life is potentially possible and independently of their origin) in terms of alkalinity, acidity, DOC, salinity, temperature, light and mixing regime will be outlined. Lakes characterized by more than a single extreme a…
Macroscopic and Molecular Insights from CO Adsorption on NaY Zeolite: A Combined FTIR and Manometric Study
2012
International audience; This survey combines both quantitative and IR molecular descriptions and aims to provide new insights for the description of CO adsorption on NaY zeolite at 77 K. Quantitative measurements of the number of CO molecules trapped in the microporous super cage are compared to the corresponding IR spectra of CO as adsorbed species. We demonstrate that polycarbonyls formed during the completion of the accessible S-II Na+ coordinative vacancies result in the formation of mono-, di- and tricarbonyls but not consecutively. Quantitative analysis and measurements of the CO molecules that are adsorbed prove that polycarbonyls coexist with different proportions over the adsorptio…
Surface characterization of metal ions loaded TiO2 photocatalysts: structure-activity relationship
2004
Transition metal loaded TiO2 powders were characterised and tested for the photodegradation of some organic acids. Both Lewis and Brønsted surface acid sites were present in the samples containing large amounts of Mo, V and W. The Brønsted sites are associated to the presence of the transition metals as they do not exist in the unloaded support, and in particular to the presence of these metals in high oxidation states. The trend of the pzc values of the various powders matches rather well both with the surface acidity of the samples experimentally determined by NH3 adsorption and with a scale of acidity/basicity for bulk binary oxides. XPS investigation indicates that only the presence of …
Comparison of 24-h control of gastric acidity by three different dosages of pantoprazole in patients with duodenal ulcer
1998
Background It is now clear that the extent to which gastric acid secretion must be suppressed varies with the clinical condition being treated. Aim To assess the 24-h control of gastric acidity and the individual response variability of three different doses of pantoprazole. Methods Sixty-four duodenal ulcer patients were recruited for this prospective, randomized, multicentre, double-blind, parallel-group study. They were subdivided into three well-matched groups treated with 20 mg o.m., 40 mg o.m. and 40 mg b.d. of pantoprazole, respectively. Endoscopy and intragastric pH monitoring were performed in each patient before and after 14 days of treatment. Results Fifty-five patients were elig…
Yield and Fruit Quality Characterization of Eight Old Sicilian Apple Cultivars
2011
In this trial, we examined the quality of eight old Sicilian apple cultivars (‘Cannamelo’, ‘Cardinale’, ‘Gelata Cola’, ‘Gelata’, ‘Granatino’, ‘San Giuseppe’, ‘Virticchiaro’, ‘Zitella’) and a commercial one (‘Annurca’ traditional clone) through bio-agronomic performances and chemical-physical analyses. We also analyzed flowering time, ripening time, pomological characteristics, and generated a specific descriptor list that indicates a great variability among the cultivars. The data obtained showed interesting characteristics in ‘Granatino’, ‘Virticchiaro’, and ‘Zitella’, such as total soluble solid, fruit size, peel cover color, yield efficiency, and crop load.
Gastric Emptying in Infants with Gastroesophageal Reflux: Ultrasound Evaluation before and after Cisapride Administration
1992
The present study aimed to evaluate gastric emptying in children with gastroesophageal reflux (GER) by means of real-time ultrasonography, on the basis of measurements of the cross-sectional area of the gastric antrum. Twelve children with GER were studied (seven males, five females; age range, 3-13 months) and compared with 12 normal control children (six males, six females; age range, 3-13 months). The diagnosis of GER was confirmed by 24-h esophageal pH-monitoring. The GER patients had a significantly greater antral area than the controls at 90, 105, and 120 min after eating a standard meal (cow's milk formula, 300 ml/m2 body surface area); in addition, final gastric emptying time was si…
Time pattern of gastric acidity in Barrett's esophagus.
1996
Increased gastroesophageal acid reflux is frequently found in patients with Barrett's esophagus, and it has been hypothesized that gastric acid hypersecretion could be an important factor aggravating the exposure of esophageal mucosa to acid and then contributing to the development of this disorder. The aim of the present study was to assess whether the circadian pattern of gastric acidity differs between refluxer patients with and without Barrett's esophagus and normal subjects. Continuous 24-hr gastric pH monitoring was performed in 119 healthy volunteers, 20 patients with Barrett's esophagus, 37 patients with moderate and 10 patients with severe reflux esophagitis without Barrett's esoph…
Evaluation of esophageal motility and reflux in children treated for congenital diaphragmatic hernia with the use of combined multichannel intralumin…
2011
Abstract Background Gastroesophageal reflux (GER) is frequently observed in children treated for congenital diaphragmatic hernia (CDH) at birth, as well as esophageal dysmotility, that has been hypothesized to be caused by innervatory anomalies. The aim of this study is to evaluate GER and dysmotility in young patients with CDH using pH-multichannel intraluminal impedance. Methods Thirty children (17 boys and 13 girls) who underwent repair for CDH between 2002 and 2007 with a median age of 5.2 years (range, 3-10 years) were included in the study. All patients were operated on with a subcostal laparotomy incision and had a left-sided diaphragmatic defect. The defect repair required an artifi…
Effect of Sunred metabolic promoter and deficit irrigation on fruit quality of 'Valencia' oranges
2012
This study evaluated the effect of deficit irrigation and Sunred foliar metabolic promoter on fruit quality of adult 'Valencia' orange trees. Three irrigation strategies were imposed in spring 2011: Irrigation with volumes corresponding to 100% of crop evapotranspiration applied to entire root-zone (CI), partial root-zone drying (PRD) with 50% of CI water applied to one alternated side of the root-zone, and continuous deficit irrigation (DI) with 50% of CI water applied to both sides of the root-zone. Four trees in each irrigation treatment were sprayed 30 and 20 days before harvest with Sunred metabolic promoter containing phenylalanine, methionine, mono-saccharides and oxylipins from plan…