Action Of Citric Acid Research Articles

Differential immobilization of cadmium and changes in soil surface charge in acidic Ultisol by chitosan and citric acid: effect of their functional groups.

Soil organic matter plays an important role in cadmium adsorption and immobilization. Since different organic matter components affect cadmium adsorption processes differently, selecting the right organic substrate and knowing how to apply it could improve cadmium remediation. This study compares the effects of two contrasting organic molecules; chitosan and citric acid, on cadmium adsorption and speciation in acidic Ultisol. The adsorption of chitosan to Ultisol significantly increased the soil positive charge while adsorption of citric acid increased the soil negative charge. At pH 5.0, the maximum amount of cadmium adsorbed in excess chitosan was 341% greater than that in excess citric acid. About 73-89% and 60-62% of adsorbed cadmium were bound to Fe/Mn oxides and organic matter/sulfide at pH 4.0 while this fraction was 77-100% and 57-58% for citric acid and chitosan at pH 5.0, respectively. This decrease in the complexing ability of chitosan was related to the destabilizing effect of high pH on chitosan's structure. Also, the sequence through which chitosan, citric acid, and cadmium were added into the adsorption system influenced the adsorption profile and this was different along a pH gradient. Specifically, adding chitosan and cadmium together increased adsorption compared to when chitosan was pre-adsorbed within pH 3.0-6.5. However, for citric acid, the addition sequence had no significant effect on cadmium adsorption between pH 3.0-4.0 compared to pH 6.5 and 7.5, with excess citric acid generally inhibiting adsorption. Given that the action of citric acid is short-lived in soil, chitosan could be a good soil amendment material for immobilizing cadmium.

Study on flotation separation of barite fluorite by citric acid under new collector system

Barite and fluorite have similar physical and chemical properties and floatability, and traditional flotation reagents are difficult to effectively separate these two minerals. In order to realize the effective separation of the two minerals, a new system with high selectivity and strong collecting ability, α-BLA ( bromododecanoic acid) system, was selected in this paper. The system can be applied at a wide range of pH values and can greatly eliminate the interference of metal ions. Therefore, this study selected this stable system to explore the effect of citric acid on barite fluorite flotation, in order to more objectively explain the adsorption mechanism of the agent. The results show that the floatability of the two minerals is quite different under the action of citric acid. Barite concentrate with grade of 81.12% and recovery of 87.74% can be obtained by micro-flotation experiment. On this basis, the interaction mechanism between citric acid and mineral surface was further studied by contact angle test, Zeta potential test, Fourier transform infrared ( FTIR), X-ray photoelectron spectroscopy ( XPS) and density functional theory ( DFT) calculation. The results show that when citric acid reacts on the surface of barite, its adsorption energy increases with the increase of bond number. The reaction on the surface of fluorite produces 3-hydroxyglutaric acid, which transfers a certain amount of electrons to Ca1 and Ca2 ions on the surface of fluorite, enhancing the chemical adsorption of citric acid on the surface of fluorite. This paper provides a theoretical basis and effective guidance for the flotation separation of barite fluorite.

Effects of Lemon Beverage Containing Citric Acid with Calcium Supplementation on Bone Metabolism and Mineral Density in Postmenopausal Women: Double-Blind 11-Month Intervention Study

A critical factor for preventing osteoporosis after menopause is attenuation of the accelerated turnover rate of bone metabolism. The present randomized controlled study was conducted to clarify the effects of a lemon beverage with calcium (Ca) supplementation that makes use of the chelating action of citric acid. Comprehensive evaluations of bone were performed by assessments of bone mineral density (BMD) and biomarkers related to bone turnover. Seventy-nine postmenopausal women were enrolled and asked to participate in an 11-month continuous intake of the test beverages. The subjects were divided into three groups: those who consumed a lemon beverage containing citric acid with Ca supplementation (LECA group), those who consumed a lemon beverage containing citric acid without Ca supplementation (LE group), and those who consumed no test beverage (control group). Using a double-blind protocol, subjects in the LECA and LE groups consumed one bottle containing 290 mL of the test beverage each day. The ratio of change in BMD after 11 months was significantly higher in the LECA group as compared to the control and LE groups. The LECA group also showed significant decreases in concentrations of tartrate-resistant acid phosphatase 5b (TRACP-5b), a bone resorption marker, and bone alkaline phosphatase (BAP) as compared to the other groups, as well as a significant decrease in concentration of osteocalcin (OC), a bone formation marker, as compared to the LE group. Based on our findings, we speculated that bone resorption and bone formation in postmenopausal women might be suppressed along with an increase in Ca resorption caused by chelation of citric acid in association with continuous ingestion of a Ca-supplemented lemon beverage containing citric acid, resulting in suppression of high bone metabolic turnover. In addition, the results provide information regarding BMD maintenance in the bones of the trunk, including the lumbar spine and proximal femur.

MORPHOLOGICAL COMPOSITION OF BLOOD AND BIOCHEMICAL PROCESSES IN THE ORGANISM OF FEMALE RATS F1 UNDER LONG-TERM EXPOSURE OF CITRIC ACID

The paper considers the effect on rats of long-term feeding of an aqueous solution of citric acid (C6H12O6 x H2O, "chemically pure.") in the amount of 8 mg/l. The study was performed on 10 laboratory female rats F1 of the Wistar line, obtained from F0 females. Two groups were set up: control and experimental, 5 animals in each. Animals were under standard conditions with natural light regime day/night, aqueous solutions of citrate, water, and feed received ad libitum. Were determined the morphological composition and biochemical parameters of the blood of female F1 rats. The results of the study indicate the absence of an unfavorable effect of citric acid on red blood cells. Concerning white blood, there is a decrease in the number of leukocytes, which may be due to the development of an adaptive response of the body to citric acid or the inhibition of citric acid's immune response to long-term adaptive action. There is a significant increase in the relative content of eosinophils in females F1, which probably may be due to the action of citric acid. The analysis of the obtained results of blood biochemical parameters indicates a certain tendency to decrease, in terms of control, the content of serum iron, as well as its total and unsaturated Fe-binding capacity. Ferrum saturation of serum transferrin was present at the level of animals in the control group. Analysis of the study results indicates no changes in control in the activity of enzymes: Alkaline phosphatase ALT and AST, also have no statistically significant confirmation of differences in the control group. The level of urea was statistically not significantly higher in terms of control. Thus, long-term watering of citric acid to female rats in the generation F0 and F1 during their physiological and sexual gestation and pregnancy reveal un-favorable effects in female rats F1. However, there was distinguished the adaptive immune-biological response of the animals organism. The immunological response was supported by a decrease in the number of leukocytes and a significant increase in the relative content of eosinophils. The results of biochemical studies of serum indicate the absence of statistically significant differences in animals of the control group.

FTIR and SEM of a novel chemical conditioning on the zirconia intaglio surface

Objectives: The aim of this study was to evaluate chemical and topographical changes in the intaglio zirconia surface induced by chemical conditioning solutions using FTIR and SEM analysis. Material and method: twelve plates for each FTIR and SEM tests from each zirconia materials (UPCERA HT White, BruxZir® Solid Zirconia, and Copran® Multilayer), milled by a Yenadent CAD/CAM system, sintered and divided randomly into a three groups. A different surface conditioning was applied to the intaglio surface of each group: 30% hydrogen peroxide, 30% citric acid and control group. Result and discussion: by using of the FTIR spectroscopy, an evidence of new bands formation appeared at 1637cm-1 and 3352cm-1 due to the high oxidizing effect of hydrogen peroxide, and at 630cm-1 and 1663cm-1 due to the chelating action of citric acid, and simultaneously, SEM assessment of the surface topography took place, to identify lines, scratches, or surface dissociation that appeared on the intaglio zirconia surface after conditioning. Conclusion: such analysis provides an enhancement of new convenient, less expensive, reliable trials to improve micro-bond strength of luting cement to Y-TZP ceramics.

Roles of citric acid in conjunction with saline nebulization in experimental tracheostomy in guinea pigs

Purpose: Tracheostomy usually accompanied by the impairment of cough reflex, which may affect the clearance of secretions and result in the occurrence and development of pulmonary inflammation. Previous research has demonstrated that citric acid could effectively evoke cough. However, there are limited data available on this topic specific to the cough stimulation method, and the roles of citric acid in tracheostomy still remain obscure. The aims of present study were to identify the potential roles of citric acid in conjunction with saline nebulization in tracheostomy in guinea pigs. Materials and Methods: Experimental tracheostomy model was induced in guinea pigs, and different nebulization interventions were implemented. The expression of P-selectin and platelet count were analyzed by flow cytometer and automatic globulimeter, the histological changes in trachea and lung tissue were assessed by hematoxylin and eosin staining, and the inflammatory cytokines and substance P (SP) levels in bronchoalveolar lavage fluid were evaluated by enzyme-linked immunosorbent assay. Results: Tracheostomy resulted in the disorder of trachea mucosa and cilia, the inflammatory cell infiltration in lung tissue, the increase of IL-6, TNF-α levels and the decrease of SP level. Citric acid alone increase the SP level, and the joint action of citric acid and saline nebulization further showed significantly beneficial effects on pathological, inflammatory changes and SP level.Conclusions: Citric acid combined with saline nebulization contributes to the alleviation of tracheotomy-induced tracheal damage and pulmonary inflammation in an experimental tracheostomy model in guinea pigs. This may provide novel insights into the inflammation management and cough recovery after tracheostomy.

The kinetic characteristics of natural antioxidants in vegetable oils

The total content and activity of natural antioxidants of the phenol type in coconut, palm, corn, and rice oils were measured by the chemiluminescent method. The existence of antioxidants of two types in palm and rice oils was shown. The synergistic action of citric acid in the presence of tocopherol was observed for the example of coconut oil.

Response of the periapical tissue of dogs' teeth to the action of citric acid and EDTA

The purpose of this study was to analyze the inflammatory response of dog's periapical tissues to 17% trisodium EDTA salt (pH 8.0) and 1% citric acid (pH 2.0). Saline was used as a control. Six adult dogs were used as the biological model of the study. The experimental units comprised 56 roots of mandibular molars (first and second) and premolars (first, second and third). After coronal opening, pulpectomy and root canal instrumentation were performed using the above-mentioned irrigating solutions. After 24 and 48 hours, the animals were euthanized and the teeth and their supporting tissues were removed and histologically processed. The sections were stained with hematoxylin and eosin and analyzed histopathologically with a light microscope at x100 magnification. The histological analysis focused on the occurrence of acute inflammatory response. The presence of swelling, vasodilatation and inflammatory cells were evaluated and the degree of inflammation was determined for each case. Data were analyzed by Fisher's exact test using the SPSS software with a confidence interval of 95% (p<0.05). 17% EDTA and 1% citric acid caused inflammatory responses in dog's periapical tissues with no significant differences to each other or to saline (control) at either the 24-hour (p=0.482) or 48-hour (p=0.377) periods. It may be concluded that the inflammatory response was of mild intensity for the tested substances.

Action de l'acide citrique sur l'anhydride acetique et la pyridine: Determination du mecanisme reactionnel et de la structure du compose forme

This study outlines the structure of the coloured by-product obtained by the action of citric acid on acetic anhydride and pyridine. The methods used are 13C nuclear magnetic resonance, infrared spectrometry and mass spectrometry. The reaction scheme proposed indicates that the compound is pyridinium aconitate. The chemical structure is corroborated by mass spectrometry.

Exsolution in terrestrial and lunar plagioclases revealed by chemical etching

A new chemical etching technique reveals fine scale exsolution structures on polished surfaces of plagioclases in the bytownite and labradorite range. A very obvious blue and locally brown stain is produced (by the action of citric acid) in growth zones of a restricted range of compositions on etched surfaces. The blue-stained zones contain very fine grooves, corresponding to the traces of thin exsolution lamellae. Exsolution features have been revealed in this way in plagioclases in a terrestrial diabase, lunar basalts and an amphibolite. Compositions of the exsolved areas found by microprobe analysis represent averages of the matrix and exsolution lamellae. Analytical methods with higher spatial resolution are required to determine the composition of the lamellae. This etching method permits easy optical identification of compositional zoning and of fine scale exsolution over relatively large areas and is therefore complementary to other techniques.