Search results for "hydration"
showing 10 items of 217 documents
The effects of ultrasonication, fermentation with Lactobacillus sp., and dehydration on the chemical composition and microbial contamination of bovin…
2018
The aim of this study was to evaluate the influence of ultrasonication, fermentation with Lactobacillus plantarum LUHS135 and Lactobacillus paracasei LUHS244, and different methods of dehydration on the chemical composition of bovine colostrum (BC), including the fatty acid and free amino acid profile and the content of micro- and macroelements. In addition, we analyzed the changes in lactic acid bacteria count, microbial contamination (aerobic mesophilic spore-forming bacteria, enterobacteria including Escherichia coli, and fungi/yeasts), the abundance of biogenic amines, and the concentration of nucleotide monophosphates. Significant effects of different treatments on the free amino acid …
Protection of Saccharomyces cerevisiae by a layer-by-layer system : effect on yeast metabolic activity in response to environmental conditions
2016
In order to protect the Saccharomyces cerevisiae yeast during dehydration, two strategies were used to improve cell survival. Strengthening cell resistance (internal protection) was performed by improving the concentration of intracellular glutathione in yeast. Encapsulation was performed by layer-by-layer method using two biopolymers β-lactoglobulin and alginate for the external protection of the yeast. The adequate medium culture and favorable growing conditions for glutathione enhancement were determined. The composition of the culture medium is rich in nutrients and glutathione precursors consisting in 30 g/L glucose, 30 g/L yeast extract, 0.6 g/L KH2PO4 and 0.6 g/L cysteine. The succes…
Chemical Identification at the Solid–Liquid Interface
2017
Solid-liquid interfaces are decisive for a wide range of natural and technological processes, including fields as diverse as geochemistry and environmental science as well as catalysis and corrosion protection. Dynamic atomic force microscopy nowadays provides unparalleled structural insights into solid-liquid interfaces, including the solvation structure above the surface. In contrast, chemical identification of individual interfacial atoms still remains a considerable challenge. So far, an identification of chemically alike atoms in a surface alloy has only been demonstrated under well-controlled ultrahigh vacuum conditions. In liquids, the recent advent of three-dimensional force mapping…
Three-dimensional hydration layer mapping on the (10.4) surface of calcite using amplitude modulation atomic force microscopy
2014
Calcite, the most stable modification of calcium carbonate, is a major mineral in nature. It is, therefore, highly relevant in a broad range of fields such as biomineralization, sea water desalination and oil production. Knowledge of the surface structure and reactivity of the most stable cleavage plane, calcite (10.4), is pivotal for understanding the role of calcite in these diverse areas. Given the fact that most biological processes and technical applications take place in an aqueous environment, perhaps the most basic - yet decisive - question addresses the interaction of water molecules with the calcite (10.4) surface. In this work, amplitude modulation atomic force microscopy is used…
Anhydrobiosis in yeast: influence of calcium and magnesium ions on yeast resistance to dehydration-rehydration
2010
The influence of calcium and magnesium ions on resistance to dehydration in the yeast, Saccharomyces cerevisiae, was investigated. Magnesium ion availability directly influenced yeast cells' resistance to dehydration and, when additionally supplemented with calcium ions, this provided further significant increase of yeast resistance to dehydration. Gradual rehydration of dry yeast cells in water vapour indicated that both magnesium and calcium may be important for the stabilization of yeast cell membranes. In particular, calcium ions were shown for the first time to increase the resistance of yeast cells to dehydration in stress-sensitive cultures from exponential growth phases. It is concl…
CE characterization of potential toxic labile iron in colloidal parenteral iron formulations using off-capillary and on-capillary complexation with E…
2007
The present study describes the application of CZE to investigate the portion of labile iron in the following parenteral formulations: iron gluconate, iron saccharate, and iron dextran. Labile iron was detected as Fe(III)-chelate of EDTA at 246 nm. When EDTA was incubated with the formulations before electrophoresis, labile iron, or chelatable iron, respectively, was detected in all formulations, mostly in iron gluconate and iron saccharate. It was observed that the amount of iron released is time- and pH-dependent. In contrast, when EDTA was separately injected before the formulation sharp peaks of the Fe(III)-chelate were detected only after injection of iron gluconate. This type of labil…
Mass Transport Analysis of Bicarbonate Buffer: Effect of the CO2–H2CO3 Hydration–Dehydration Kinetics in the Fluid Boundary Layer and the Apparent Ef…
2019
The main buffering system influencing ionizable drug dissolution in the human intestinal fluid is bicarbonate-based; however, it is rarely used in routine pharmaceutical practice due to the volatility of dissolved CO2. The typical pharmaceutical buffers used fail to capture the unique aspects of the hydration-dehydration kinetics of the bicarbonate-CO2 system. In particular, CO2 is involved in a reversible interconversion with carbonic acid (H2CO3), which is the actual conjugate acid of the system, as follows CO2 + H2O ⇌ H2CO3. In contrast to ionization reactions, this interconversion does not equilibrate very rapidly compared to the diffusional processes through a typical fluid diffusion b…
Cryopreservation of Escherichia coli K12TG1: Protection from the damaging effects of supercooling by freezing
2015
Injuries in living cells caused by water freezing during a freeze-thaw process have been extensively reported. In particular, intracellular water freezing has long been incriminated in cell death caused by a high cooling rate, but this supposition could not always be demonstrated. This work aims to discriminate the role of water freezing, dehydration and cold-induced injuries in cellular damage occuring during cryopreservation. For this purpose, Escherichia coli K12TG1 suspensions were maintained in a supercooled or frozen state at -20°C for times ranging from 10 min to 5 h. The supercooled state was maintained for a long period at -20°C by applying a non-injurious isostatic pressure (P<40 …
Characterization by solid-state NMR and selective dissolution techniques of anhydrous and hydrated CEM V cement pastes.
2010
International audience; The long term behaviour of cement based materials is strongly dependent on the paste microstructure and also on the internal chemistry. A CEM V blended cement containing pulverised fly ash (PFA) and blastfurnace slag (BFS) has been studied in order to understand hydration processes which influence the paste microstructure. Solid-state NMR spectroscopy with complementary X-ray diffraction analysis and selective dissolution techniques have been used for the characterization of the various phases (C3S, C2S, C3A and C4AF) of the clinker and additives and then for estimation of the degree of hydration of these same phases. Their quantification after simulation of experime…
Hydration of tricalcium aluminate in the presence of various amounts of calcium sulphite hemihydrate : Conductivity tests.
2006
Abstract Hydration of calcium aluminate C3A (3CaO·Al2O3) in the presence of calcium sulphite hemihydrate (CaSO3·0.5H2O), with the molar ratio of substrates close to 1, produces the C3A·CaSO3·11H2O calcium monosulphite aluminate phase. Small amounts of calcium sulphite added to calcium aluminate (the ratio of CaSO3·0.5H2O / C3A equalling 0 : 1) change the rate of C3A hydration and influence the whole reaction. Reaction processes for various ratios of the C3A–CaSO3·0.5H2O mixture were examined in pure distilled water with a considerable amount of liquid W / S = 38–50 (constant W / C3A). Processes in the liquid phase were monitored with conductivity equipment, and the XRD analysis was used to …