Search results for "CARBONATE"
showing 10 items of 920 documents
Post-tilleyite, a dense calcium silicate-carbonate phase
2019
Scientific reports 9(1), 7898 (2019). doi:10.1038/s41598-019-44326-9
Single nanogranules preserve intracrystalline amorphicity in biominerals.
2015
We revisit the ultrastructural features of different calcareous biominerals and identify remarkable similarities: taxonomically very distant species show a common nanogranular structure, even if different extracellular secretion patterns are employed or calcium carbonate polymorphs formed. By these analyses, we elucidate the locus of the small fraction of intracrystalline organic matrix revealing its intergranular character and localize the intracrystalline amorphous calcium carbonate moiety commonly found in mesocrystalline biominerals and provide a first explanation for the pathway by which it is preserved.
Point-of-care evaluation of a rapid antigen test (CLINITESTⓇ Rapid COVID-19 Antigen Test) for diagnosis of SARS-CoV-2 infection in symptomatic and as…
2021
AbstractRapid antigen assays (RAD) based on lateral flow immunochromatography (LFIC) technology have emerged as a valuable tool for the control of COVID-19 pandemic. Manufacturer□independent, real□world evaluation of these assays is crucial given the considerable heterogeneity reported in their clinical and analytical performances. Here, we report for the first time on the point-of-care performance of the CLINITEST® Rapid COVID-19 Antigen Test (Siemens, Healthineers, Erlangen, Germany) to detect SARS-CoV-2 infection in presumptive COVID-19 cases or asymptomatic close contacts of COVID-19 patients. When compared to RT-PCR, the overall sensitivity of the assay was 80.2 (95% CI, 70.9-87.1) for…
Anti-erosive effect of calcium carbonate suspensions
2018
Background This study aimed to investigate the ability of different concentrations of calcium carbonate (CaCO3) suspensions to control enamel surface loss. Material and methods Seventy-five enamel slabs were embedded, ground and polished in a pneumatic grinder-polisher machine. Reference areas were created with UPVC tape and the specimens were randomly allocated into five groups (n = 15) for exposure to hydrochloric acid solution to simulate gastric juice (0.01 M, pH 2) for 2 minutes. The samples were then exposed to suspensions containing 0.0001, 0.001, 0.01 or 0.1 mmol/L CaCO3 for 1 minute. Artificial saliva was used as control. The samples were subjected to a total of five erosive cycles…
Enteric bacteria of food ice and their survival in alcoholic beverages and soft drinks
2017
This study aimed to evaluate the levels of enteric bacteria in ice cubes produced in different environments (home-made, prepared in bars and pubs with ice machines and produced in industrial plants) and to determine their survival in different alcoholic beverages and soft drinks. Members of the Enterobacteriaceae family were found in almost all samples analysed. All industrial and the majority of home-made samples did not contain coliforms. Enterococci were not identified in domestic samples while they were detected in two industrial and three bar/pub samples. The samples collected from bars and pubs were characterized by the highest levels of enteric bacteria. Fourteen strains representing…
Carbonic anhydrase and metazoan biocalcification: a focus on molluscs.
2015
Carbonic anhydrase is a super-family of metallo-enzymes (containing α, β, γ, ζ and δ-CA families) that catalyse the reversible hydration of carbon dioxide. Among their numerous functions, CAs - in particular that of the α-CA family - are known to play a key role in biocalcification processes, i.e., the ability to deposit calcium carbonate crystallites in a controlled manner to form exoskeletons. In the gastropod mollusc Haliotistuberculata – the European abalone – we identified two CA transcripts, htCA1 and htCA2, in the mantle, the calcifying organ responsible for shell formation from an extracellular organic matrix and a mixture of inorganic ions. Because these two transcripts are specifi…
The shell of the invasive bivalve species Dreissena polymorpha: biochemical, elemental and textural Investigations.
2016
28 pages; International audience; The zebra mussel Dreissena polymorpha is a well-established invasive model organism. Although extensively used in environmental sciences, virtually nothing is known of the molecular process of its shell calcification. By describing the microstructure, geochemistry and biochemistry/proteomics of the shell, the present study aims at promoting this species as a model organism in biomineralization studies, in order to establish a bridge with ecotoxicology, while sketching evolutionary conclusions. The shell of D. polymorpha exhibits the classical crossed-lamellar/complex crossed lamellar combination found in several heterodont bivalves, in addition to an extern…
The consumption of snacks and soft drinks between meals may contribute to the development and to persistence of gastro-esophageal reflux disease
2019
Abstract The hypothesis The habit of snacking and drinking soft beverages between breakfast, lunch and dinner, which is very widespread in the western world, could be a primum movens, thereby contributing to the development and subsequent persistence of gastroesophageal reflux disease (GERD). What does the proposed hypothesis based on? The high prevalence of GERD suggests that it is very probably caused by factors, which are intrinsic and widespread in a western lifestyle. Ingesting snacks or imbibing soft drinks between breakfast, lunch and dinner causes additional gastric acid secretion, acid pocket formation, and additional transient lower esophageal sphincter relaxations (TLESRs) with a…
Assessment of Usability of Thermal Bicarbonate Mineral Water from the “Odra-5/I” Intake in Grabin Opole Silesia (SW Poland) for Therapeutic and Proph…
2020
Thermal bicarbonate mineral water belong to sought-after balneological resources. This kind of water are a balneological product and valuable raw material used in health resorts for the wider health strategy - prophylaxis and recreation. The discovery of thermal bicarbonate mineral water in Grabin near Opole in 1983 was purely incidental when a intake was made for the recognition of the geological structure of the crystalline basement of Mesozoic and Cenozoic sediments. Thermal bicarbonate mineral water existing in Grabin can be found in the Fore-Sudetic block and is a unique phenomenon. Its chemical composition, and especially high total mineral salt content of the waters from Grabin, indi…
Mechanistic understanding of underperforming enteric coated products: Opportunities to add clinical relevance to the dissolution test.
2020
Over the last 70 years several cases of in vivo failure of enteric coated (EC) formulations have been reported. The observed failures seem to be due to the slower than expected in vivo performance of EC products. Upon reaching the intestinal lumen, the dosage form is exposed to a bicarbonate buffered environment at much lower interfacial buffering capacity compared to those applied in compendial phosphate buffers. Hence, there is an urgent need to understand the behavior of EC products in bicarbonate buffer (BCB) and to revaluate the current dissolution methods used for such products. The current pilot study mechanistically investigated the performance of five EC products available in the C…