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Query: UMLS:C0847097 (acidity)
 15,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A typical American diet contains amounts of sodium chloride far above evolutionary norms and potassium far below those norms. It also contains larger amounts of foods that are metabolized to noncarbonic acids than to organic bases. At baseline, in a steady state, diets that contain substantial sodium chloride and diets that are net acid producing each independently induce and sustain increased acidity of body fluid. With increasing age, the kidney's ability to excrete daily net acid loads declines, invoking homeostatically increased utilization of base stores (bone, skeletal muscle) on a daily basis to mitigate the otherwise increasing baseline metabolic acidosis, which results in increased calciuria and net losses of body calcium. Those effects of net acid production and its attendant increased body fluid acidity may contribute to development of osteoporosis and renal stones, loss of muscle mass, and age-related renal insufficiency. The inverted ratio of potassium to sodium in the diet compared with preagricultural diets affects cardiovascular function adversely and contributes to hypertension and stroke. The diet can return to its evolutionary norms of net base production inducing low-grade metabolic alkalosis and a high potassium-to-sodium ratio by 1) greatly reducing content of energy-dense nutrient-poor foods and potassium-poor acid-producing cereal grains, which would entail increasing consumption of potassium-rich net base-producing fruits and vegetables for maintenance of energy balance, and 2) greatly reducing sodium chloride consumption. Increasingly, evidence supports the health benefits of reestablishing evolutionary norms of dietary net base loads and high potassium and low sodium chloride loads. We focus here on the American diet's potential effects on bone through its superphysiologic content of sodium chloride.
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PMID:Adverse effects of sodium chloride on bone in the aging human population resulting from habitual consumption of typical American diets. 1820 14

Eighteen physical and chemical variables were determined in 25 samples of commercial tomato products: total solids, soluble solids, water activity, lycopene, 5-hydroxymethyl-2-furfural, CIE(L*a*b*) components (L*, a*, b*, a*/b*, C*, H degrees), total acidity, sodium chloride, wet-weight pulp percentage, alcohol insoluble solids, total pectic substances, ascorbic acid, and pH. In order to maximize the variability of products, samples included crushed tomato, tomato puree, tomato paste, and heavy concentrates and were taken from Italy, France, Spain, Portugal, the United States, Mexico, Colombia, and Chile. Correlation analysis and multidimensional data analysis techniques (principal component analysis and hierarchical classifications) were used to describe the products' variability and to study the relationships among variables. Three variables were selected, with the aim of classifying the collection of samples in a way consistent with the classification obtained with the first principal components. These variables were soluble solids content, the CIE(L*a*b*) lightness parameter L*, and total pectic substances content.
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PMID:Use of physical and chemical properties of commercial tomato (Lycopersicon esculentum Mill.) products for monitoring their quality. 1837 93

It was of interest to develop a method for solid-state acidity measurements using pH indicators and to correlate this method to the degradation rate of sucrose. Amorphous samples containing lactose 100mg/ml, sucrose 10mg/ml, citrate buffer (1-50mM) and sodium chloride (to adjust the ionic strength) were prepared by freeze-drying. The lyophiles were characterized using powder X-ray diffraction, differential scanning calorimetry and Karl Fischer titremetry. The solid-state acidity of all lyophiles was measured using diffuse reflectance spectroscopy and suitable indicators (thymol blue or bromophenol blue). The prepared lyophiles were subjected to a temperature of 60 degrees C and were analyzed for degradation using the Trinder kit. The results obtained from this study have shown that the solid-state acidity depends mainly on the molar ratio of the salt and the acid used in buffer preparation and not on the initial pH of the solution. The degradation of sucrose in the lyophiles is extremely sensitive to the solid-state acidity and the ionic strength. Reasonable correlation was obtained between the Hammett acidity function and sucrose degradation rate. The use of cosolvents (in the calibration plots) can provide good correlations with the rate of an acid-catalyzed reaction, sucrose inversion, in amorphous lyophiles.
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PMID:Influence of solid-state acidity on the decomposition of sucrose in amorphous systems. I. 1864 42

The uptake of the sulphonated azo dye [1-(tetrazolylazo)-2-hydroxynaphthalene 3,6-disulphonic acid, or T-azo-R] by bovine serum albumin (BSA) in the pH range 1-4 was investigated by a spectrophotometric method, based on the fact that the absorption spectra of the free and bound dye are different. The effect of increasing concentration of sodium chloride and sodium perchlorate was considered, as well as the influence of the BSA on the protonation equilibria of the dye. The Scatchard model, which has been widely used previously to describe the interaction between small substances and proteins, was not helpful in the treatment of data obtained in the acidity range considered here. Instead a phase distribution model allowed a good quantitative treatment of the experimental findings. The distribution constant of the monoprotonated T-azo-R between aqueous solution and the albumin microphase was found to be log K(d(HL)/gamma'HL) = 6.3, while the biprotonated form does not bind to BSA. As a consequence, the protonation constant of T-azo-R is decreased in the presence of BSA, particularly at low salt concentrations in aqueous solution. An equation relating the observed protonation constant to the protonation constant of the dye in solution and to the ionic strength is proposed. It has been found that the effect of salts on the uptake of T-azo-R by BSA can be explained simply by considering the variation of the activity coefficients of the ionic species involved in aqueous solution.
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PMID:Interaction of serum albumin with a sulphonated azo dye in acidic solution. 1896 67

Heterogeneous equilibria in saturated aqueous solutions of 8-hydroxyquinoline (A), 2-methyl-8-hydroxyquinoline (B) and 5-chloro-8-hydroxyquinoline (C) were investigated at constant ionic strength (1M sodium chloride), at 25.0 +/- 0.1 degrees , by the application of the following methods: the formation function method, the method of bound protons, the method of free proton sites and the solubility method. The following equilibrium constants were determined: K(s1)=[H(2)A(+)]/[H(3)O(+)], K(s2)=[HA] and K(s3)=[H(3)O(+)] [A(-)]. Their mean pK values are: -2.88, 2.42 and 12.09 for A, -3.27, 2.71 and 12.73 for B, and -0.34, 3.88 and 12.75 for C. In addition, the acidity constants of investigated 8-hydroxyquinolines were determined by pH-metric titrations. The values obtained for these constants were consistent with those calculated on the basis of corresponding equilibrium constants determined in heterogeneous systems.
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PMID:Study of heterogeneous equilibria in saturated solutions of some sparingly soluble 8-hydroxyquinolines. 1896 38

The interactions of Bromophenol Blue (BPB) with bovine serum albumin and gamma-globulin in acidic solutions were investigated by a spectrophotometric method. It was considered that the electrostatic force is the main binding force, and that the color change during the combination is due to the transformation of dye species of free acidic form into bound basic form as well as to the bathochromic and hyperchromic effects of conjugation. The formation of an isosbestic point in the absorption spectra was explained based on a new consideration about the solution equilibria. Two conditional constants, apparent binding constant and maximum binding number, were defined to express the binding ability of a dye to a certain protein under a given set of conditions, and two linear regression equations were derived to determine these two parameters and the molar absorptivity of bound dye. The Scatchard model is not appropriate in the treatment of data obtained here. The factors which influence the sensitivity of a dye binding protein assay were discussed, and the Sandell index was used to express the sensitivity of protein detection. It was found that sodium chloride concentration and acidity of the solutions have significant effect on the sensitivity of BPB protein assay.
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PMID:The interaction of Bromophenol Blue with proteins in acidic solution. 1896 56

A potentiometric SI titration system for the determination of total acidity in soft drinks is proposed. The concept is based on the aspiration of the acid soft drink sample between two base zones into a holding coil with the volume of the first base zone twice to that of the second one and channelled by flow reversal through a reaction coil to a potentiometric sensor. A solution of 0.1 mol l(-1) sodium chloride is used as ionic strength adjustment buffer in the carrier stream. The system has been applied to the analysis of some South African soft drinks having a total acidity level of about 0.2-0.3% (w/v). The method has a sample frequency of 45 samples per h with a linear range of 0.1 and 0.6% (w/v). It is easy to use, fully computerised, and gives the results that are comparable to both automated batch titration and manual titration.
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PMID:Determination of the total acidity in soft drinks using potentiometric sequential injection titration. 1896 46

It was of interest to investigate the solid-state acidity using indicator probe molecules and sucrose degradation. Amorphous samples containing lactose, sucrose, buffers (citrate, malate, tartarate, or phosphate) with different pH values, and sodium chloride (to adjust the ionic strength) were prepared by freeze-drying. The lyophiles were characterized using powder X-ray diffraction, differential scanning calorimetry, and Karl Fischer titrimetry. The solid-state acidity of all lyophiles was measured using diffuse reflectance spectroscopy and suitable indicators (thymol blue or bromophenol blue). Selected lyophiles were subjected to a temperature of 60 degrees C and were analyzed for sucrose degradation using the Trinder kit. The results obtained from this study have shown that good correlation can be obtained between the solid-state acidity and the molar ratio of the salt and the acid in solution. The degradation of sucrose in the lyophiles is extremely sensitive to the solid-state acidity and might be able to provide a better estimate for the acidity than the indicator probe molecules. The Hammett acidity-rate profile for sucrose degradation in the lyophiles (using four different buffers) was also obtained. The profile showed similarity to the pH-rate profile in solution, and no buffer catalysis for sucrose degradation was detected in this study.
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PMID:Influence of solid-state acidity on the decomposition of sucrose in amorphous systems II (effect of buffer). 1901 2

Electrocoagulation (EC) is an electrochemical technique which has been employed in the treatment of various kinds of wastewater. In this work the potential use of EC for the treatment of palm oil mill effluent (POME) was investigated. In a laboratory scale, POME from a factory site in Chumporn Province (Thailand) was subjected to EC using aluminum as electrodes and sodium chloride as supporting electrolyte. Results show that EC can reduce the turbidity, acidity, COD, and BOD of the POME as well as some of its heavy metal contents. Phenolic compounds are also removed from the effluent. Recovery techniques were employed in the coagulated fraction and the recovered compounds was analysed for antioxidant activity by DPPH method. The isolate was found to have a moderate antioxidant activity. From this investigation, it can be concluded that EC is an efficient method for the treatment of POME.
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PMID:Electrocoagulation of palm oil mill effluent. 1913 37

1. Under certain conditions, general autolysis does not begin immediately upon the removal of the organ from its circulation. This latent period is more apt to be present in those cases in which the tissues have been temporarily cooled on account of the use of a cold saline diluent or in which the percentage concentration of the inorganic salts (calcium or potassium), of the tissues have been changed by dilution with a sodium chloride solution. The presence of blood and absence of fats and of glycogen in the cells act as important factors in prolonging the latent period. 2. Attempts to produce an alkaline reaction (phenolphthalein) in the tissue resulted negatively. Solutions of disodium hydrogen phosphate and of sodium bicarbonate when added to the liver tissues gave a mixture which was acid to phenolphthalein and had no apparent effect upon autolysis. 3. The addition of antiseptics-chloroform and toluol-markedly decreased the rate of autolysis. Ordinary light produced no effect. 4. Ethyl butyrate when added to the tissue became hydrolysed into butyric acid; the formation of this acid in the mixture caused a decided acceleration in the autolytic rate. The acidity of a solution of dihydrogen sodium phosphate failed to produce a similar result. 5. The figures for the changes in the depression of the freezing-point, non-coaguable nitrogen and reaction of the autolytic mixture do not parallel one another. In some experiments a marked increase in the depression of the freezing-point was unaccompanied by augmentation of non-coagulable nitrogen. 6. General autolysis is the sum total of proteolytic, amylolytic and lipolytic factors. Each of these autolytic factors may proceed alone for a time; the rate of one is decidedly influenced by the presence or absence of the others. The acid products which are the result of amylolytic (lactic acid) and of lipolytic (higher fatty acids) autolysis, exert a pronounced augmentative effect upon the commencement and rate of nitrogenous autolysis.
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PMID:THE EFFECT OF CONDITIONS UPON THE LATENT PERIOD AND RATE OF ASEPTIC POST MORTEM AUTOLYSIS DURING THE FIRST TEN HOURS. 1986 44


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