Calcium Acetate Research Articles

Preparation of bioactive and antibacterial PMMA-based bone cement by modification with quaternary ammonium and alkoxysilane.

Bone cement based on poly(methyl methacrylate) (PMMA) powder and methyl methacrylate (MMA) liquid is a very popular biomaterial used for the fixation of artificial joints. However, there is a risk of this cement loosening from bone because of a lack of bone-bonding bioactivity. Apatite formation in the body environment is a prerequisite for cement bioactivity. Additionally, suppression of infection during implantation is required for bone cements to be successfully introduced into the human body. In this study, we modified PMMA cement with γ-methacryloxypropyltrimetoxysilane and calcium acetate to introduce bioactive properties and 2-(tert-butylamino)ethyl methacrylate (TBAEMA) to provide antibacterial properties. The long-term antibacterial activity is attributed to the copolymerization of TBAEMA and MMA. As the TBAEMA content increased, the setting time increased and the compressive strength decreased. After soaking in simulated body fluid, an apatite layer was detected within 7 days, irrespective of the TBAEMA content. The cement showed better antibacterial activity against Gram-negative E. Coli than Gram-positive bacteria; however, of the Gram-positive bacteria investigated, B. subtilis was more susceptible than S. aureus.

Influence of altered Ca-P based electrolytes on the anodised titanium bioactivity

Abstract Anodic oxidation (AO) of titanium is a common electrochemical process for surface modification of metallic surfaces and is conducted in an electrolyte solution. Anodisation of titanium implants can generate a coating with optimal characteristics to accelerate the growth of bone-like apatite. The present work aims to develop a novel AO electrolyte formulation of a Ca P base solution containing three different alteration agents. The characteristics of the anodised coating were modified by varying the volume fractions of the alteration agents, namely sulphuric acid, hydrogen peroxide, and acetic acid in a base solution of β-glycerolphosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA). The surface morphology, mineralogy, wettability, and bioactivity of these coatings were analysed using scanning electron microscopy (SEM), X-ray diffraction (XRD), contact angle analysis, and in vitro testing using simulated body fluid (SBF). Anodisation in a mixture of β-GP + CA electrolyte resulted in the formation of Ca-P-rich oxide coating (with surface features with a donut-like shape) and when altered with 12.5 vol% sulphuric acid, highly defined spiky needle-like morphology was seen on the surface. These coatings were composed of hydroxyapatite, tricalcium phosphate, and calcium diphosphate. After 7 days of SBF immersion, the surface was observed to contain a dense layer of bone-like apatite. However, alteration using acetic acid did not result in any significant changes to the surface characteristics and no bone-like apatite formation was observed even after soaking in SBF for 7 days. Alteration using hydrogen peroxide resulted in an anodised coating that assisted the growth of bone-like apatite layer on the coating surfaces after soaking in SBF for 7 days. The differences in coating performance are linked to the presence of different functional ions with hydronium groups (from sulphuric acid) being superior compared to the carboxyl ions (from acetic acid). The coating produced by sulphuric acid alteration demonstrated super hydrophilicity and rougher topographies which are ideal characteristics for cell attachment and proliferation in implant applications.

MOLECULAR MECHANISM OF RELAXATION ABSORPTION OF ULTRASONIC WAVES IN AN AQUEOUS SOLUTION OF CALCIUM ACETATE

The absorption of ultrasonic waves in the frequency range from 6 to 146 MHz in aqueous solutions of sodium acetate, sodium chloride and calcium has been studied. It was found that only in solutions of calcium cations and acetate anion present simultaneously, relaxation absorption of ultrasonic waves is observed. The experimental data obtained indicate that the observed relaxation absorption of ultrasound in the studied frequency range by an aqueous solution of calcium acetate is associated with the interaction of the acetate anion with the calcium cation in the solution.

MC3T3-E1 cell response to microporous tantalum oxide surfaces enriched with Ca, P and Mg

The formation of a porous oxide surface doped with osteoconductive elements, Ca, P and Mg, to enhance osseointegration, was achieved through micro arc oxidation. Micro arc oxidation parameters, such as electrolyte composition, concentration and applied voltage, were studied to understand their effect on the morphology and chemical composition of the samples surface.Considering the optimum atomic concentration reported in literature for each osteoconductive element, microporous Ta anodic oxide samples treated with calcium acetate (CaA) and β-glycerophosphate (β-GP) revealed that an increase of β-GP molarity in the electrolyte boosts Ca incorporation, as well as, increasing the porosity. In adding magnesium acetate (MgA) to the electrolyte, when composed by CaA + β-GP, both addition and variation of MgA did not affect the surface morphology along the samples, being incorporated into the oxide layer for 0.1 M.Finally, in vitro tests were carried out to study the biocompatibility of Ta, to verify the cytotoxicity of the samples and their behavior towards cells, by performing adhesion and differentiation tests with the MC3T3-E1 cell line. Cytotoxicity tests revealed that the samples were non-toxic. Despite none of the samples having been raised up through cell adhesion tests, cell differentiation revealed promising results for the Ta-CaP.

Isolation of alkaliphilic calcifying bacteria and their feasibility for enhanced CaCO3 precipitation in bio-based cementitious composites.

SummaryMicrobially induced calcite precipitation (MICP), secreted through biological metabolic activity, secured an imperative position in remedial measures within the construction industry subsequent to ecological, environmental and economical returns. However, this contemporary recurrent healing system is susceptible to microbial depletion in the highly alkaline cementitious environment. Therefore, researchers are probing for alkali resistant calcifying microbes. In the present study, alkaliphilic microbes were isolated from different soil sources and screened for probable CaCO3 precipitation. Non‐ureolytic pathway (oxidation of organic carbon) was adopted for calcite precipitation to eliminate the production of toxic ammonia. For this purpose, calcium lactate Ca(C3H5O3)2 and calcium acetate Ca(CH3COO)2 were used as CaCO3 precipitation precursors. The quantification protocol for precipitated CaCO3 was established to select potent microbial species for implementation in the alkaline cementitious systems as more than 50% of isolates were able to precipitate CaCO3. Results suggested 80% of potent calcifying strains isolated in this study, portrayed higher calcite precipitation at pH 10 when compared to pH 7. Ten superlative morphologically distinct isolates capable of CaCO3 production were identified by 16SrRNA sequencing. Sequenced microbes were identified as species of Bacillus, Arthrobacter, Planococcus, Chryseomicrobium and Corynebacterium. Further, microstructure of precipitated CaCO3 was inspected through scanning electron microscopy (SEM), X‐ray diffraction (XRD) and thermal gravimetric (TG) analysis. Then, the selected microbes were investigated in the cementitious mortar to rule out any detrimental effects on mechanical properties. These strains showed maximum of 36% increase in compressive strength and 96% increase in flexural strength. Bacillus, Arthrobacter, Corynebacterium and Planococcus genera have been reported as CaCO3 producers but isolated strains have not yet been investigated in conjunction with cementitious mortar. Moreover, species of Chryseomicrobium and Glutamicibacter were reported first time as calcifying strains.

Eggshells as a sustainable source for acetone production

Everyday, tons of food wastes are thrown to the environment constantly by people in the cities, which contain many beneficial substances. One of these beneficial wastes of unknown value is eggshells. Although the eggshells are considered negligible and not valuable material, however, the many researches that dealt with this substance proved its high potential to turn into many useful substances such as a catalyst in biodiesel preparation or as a media for adsorption of heavy metals and dyes or soil fertilizer and others. The current study highlighted the benefit possibility of white chicken eggshells (WCES) from another side, considering it as a raw material for preparing acetone one of the most important industrial solvents. The results obtained showed that this worthless raw material has a high effectiveness for acetone production by containing 94.519% by weight of calcium carbonate. The process of converting WCES to acetone was carried out in two steps, the first one were producing calcium acetate by treating it with glacial acetic acid in a batch mode reaction unit at room temperature and agitation speed, acid % excess and contact time of 200 rpm, 20% and 2 h respectively. Whereas, the next step involved conducting the process of thermal decomposition of the prepared calcium acetate at 380 °C to produce acetone in a stainless steel reactor. The results of testing the samples by the gas chromatography (GC) showed that the maximum yield of acetone is 96.395%. With these experimental results, this study presents a new idea in food waste management as one of the solid waste types by utilizing it in a useful manner to produce important materials in an economical, beneficial and environmentally friendly way, reaching to the concept of zero residue level (ZRL).

Adsorption of Lead Ion from Wastewater Using Non-Crystal Hydrated Calcium Silicate Gel.

In order to obtain low-cost and excellent adsorption materials, this paper used calcium acetate and water glass as raw materials to synthesis hydrated calcium silicate gel by precipitation method. The performance and structure of hydrated calcium silicate gel were systematically studied by X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, specific surface area analyzer and scanning electron microscope. Studies have shown that, non-crystal hydrated calcium silicate gel (CSH) were successfully prepared, and the removal rate of lead ion using CSH reached more than 90%. The adsorption process is consistent with the pseudo-second-order kinetic model and Langmuir adsorption isotherm model, and the limit adsorption capacity reaches 263.17 mg·g−1. The acid treatment experiment proved that the adsorption capacity of lead ion using CSH was satisfactory, and the adsorption rate remained at >60% after 5 cycles. The research may provide a low-cost, high-efficiency and high stability adsorbent.

Preparation and Biological Activity of Strontium Modified Titanium Oxide Surface

Titanium (Ti) is a bone tissue replacement material with excellent mechanical properties. However, Ti has poor biological activity and lacks osseointegrative properties and may trigger inflammation and cause implantation failure. To address these issues, Ti surface modification has become a widely used method. In this study, using microarc oxidation (MAO) technology, a strontium-doped MAO coating was prepared on Ti surfaces in an electrolyte solution comprising calcium acetate, calcium glycerophosphate and strontium acetate. Scanning electron microscopy (SEM) and energy spectrum analysis (EDS) were used to analyze the tissue structure and elemental composition of the coating. The surface phase composition of the coating was analyzed by X-ray diffraction (XRD). We observed the proliferation of cells on the coating surface through in vitro cell experiments. The results showed the surface of the strontium-doped MAO coating is porous, and strontium is evenly distributed on the surface. The coating can promote the adhesion, proliferation and differentiation of osteoblasts and has good biological activity and thus, could potentially be applied to the surface of implants in clinical application.

Severe hypocalcaemia in a COVID-19 female patient.

SummaryComorbidities are a risk factor for patients with COVID-19 and the mechanisms of disease remain unclear. The aim of this paper is to present a case report of an COVID-19 patient with severe hypocalcaemia. This is a report of an 81-year-old female, suffered from myalgia and fatigue for more than 3–4 weeks. Fever and cough appear 2 days before she presented to the emergency room. On physical examination, she was febrile with a temperature of 38.8°C, accompanied by cough, sore throat, headache, fatigue, and muscle ache. Her past medical history was remarkable with no chronic disease. She had lymphopenia. Laboratory test revealed moderate liver dysfunction, hypoalbuminemia, and severe hypocalcaemia (serum corrected calcium level: 5.7 mg/dL). Parathyroid hormone (PTH) was 107.9 pg/mL (range: 15–65) and 25(OH)2D levels was 4.5 ng/mL (range: 25–80). Chest CT scan detected peripheral ground-glass opacity. Throat swab for coronavirus by RT-PCRassay tested positive for the virus. She was treated with lopinavir/ritonavir, third generation cephalosporin, anticoagulant, daily high-dose calcium acetate, vitamin D3, fresh frozen plasma and oxygen therapy. She was discharged after two negative throat swab tests for coronavirus by conventional RT-PCR.Learning pointsComorbidities are a risk factor for patients with COVID-19.Laboratory findings are unspecific in COVID-19 patients; laboratory abnormalities include lymphopenia, elevated of LDH, CPK and the inflammatory markers, such as C reactive protein, ferritinemia and the erythrocyte sedimentation rate.In addition to inflammatory markers, in COVID-19 patients it is crucial to check the level of vitamin D and calcium.There may be a correlation between vitamin D deficiency and the severity of COVID-19 disease.

Pharmacokinetics of Roxadustat: A Population Analysis of 2855 Dialysis- and Non-Dialysis-Dependent Patients with Chronic Kidney Disease

Roxadustat is a novel, small-molecule, first-in-class therapeutic that stimulates erythropoiesis by inhibiting hypoxia-inducible factor prolyl hydroxylase enzymes. This agent (roxadustat) is in clinical development for the treatment of anemia in patients with non-dialysis-dependent (NDD) and dialysis-dependent (DD) chronic kidney disease. A population pharmacokinetic analysis was undertaken to evaluate the effect of intrinsic and extrinsic factors on roxadustat pharmacokinetics. Non-linear mixed-effects models implemented in NONMEM software were fitted to 8209pharmacokinetic samples from 2855 DD and NDD subjects enrolled in four phase III studies with roxadustat dose concentrations of 20-400 mg as orally administered tablets. Effects of intrinsic and extrinsic factors were evaluated using a stepwise covariate modeling procedure in combination with the full covariate approach, and defined no-effect boundaries for exposure were based on the difference in exposure between 70 and 100 mg of roxadustat (i.e., - 30%, + 43%). A two-compartment model with first-order absorption adequately described roxadustat pharmacokinetics, with parameter estimates (relative standard error) for apparent clearance of 1.1 (0.0223) L/h in NDD subjects, and apparent central and peripheral volumes of distribution of 14.9 (0.0278) L and 9.5 (0.0872) L, respectively. Stepwise covariate modeling identified bodyweight, dialysis status, race, and dose as statistically significant covariates on apparent clearance, and bodyweight, sex, and albumin as statistically significant covariates on apparent central volume of distribution. However, the effects of these covariates did not result in roxadustat area under the curve or maximum plasma concentration changes outside of the defined no-effect boundaries. The effects of concomitant oral iron, clopidogrel, and staggered sevelamer, calcium carbonate, or calcium acetate were investigated using a full covariate approach but did not result in roxadustat area under the curve or maximum plasma concentration changes outside of the defined no-effect boundaries. A population pharmacokinetic model was developed for the pharmacokinetics of roxadustat in the target population. None of the investigated intrinsic or extrinsic factors resulted in a significant change in roxadustat exposure outside of the defined no-effect boundaries.

Simple and Rapid Synthesis of Calcium Acetate from Scallop Shells to Reduce Environmental Issues

The search for sustainable resources remains a subject of global interest. Calcium acetate used in many fields was prepared using waste scallop shell as a raw material, and its physicochemical properties were investigated. The waste scallop shells were transformed to calcium acetate compounds by reactions with four acetic acid concentrations at ambient temperature until the completely dried powder is obtained. The maximum yield of 87% with short reaction time at a low temperature was observed in the reaction of 60%w/w acetic acid with scallop shells. Thermal transformation reactions of all prepared calcium acetate samples revealed temperature conditions for heating to produce other advanced materials. FTIR and XRD results confirmed the purity and solid phase of all prepared calcium acetate samples, and they were compared with those of literatures and found to be well consistent. The obtained timber-like particles have different sizes depending on the acetic acid concentration. This work reports an easy and low-cost method with no environmental effect to produce cheap calcium products to be used in the industry.

Catalytic Co-Pyrolysis of Food Waste Digestate and Corn Husk with CaO Catalyst For Upgrading Bio-Oil

The catalytic co-pyrolysis behavior of food waste digestate (FD) and corn husk (CH) with CaO catalyst for upgrading bio-oil was studied. Two kinds of CaO catalysts derived from calcining calcium hydroxide (CH-CaO) and calcium acetate monohydrate (CA-CaO) were used in this work. The char yield decreased while the bio-oil and non-condensable gas yields increased with the CH/FD mass ratio increased. Gas chromatography/mass spectrometry results showed that bio-oil from food waste digestate pyrolysis was rich in nitrogen-containing compounds (NCCs), resulting in the pH of bio-oil exhibited weak alkaline. The acid compounds in bio-oil could adjust the pH to be neutral or weakly acidic with the addition of CH. For catalytic co-pyrolysis, the relative contents of acids and esters in bio-oil decreased while the phenols increased. The contents of NCCs especially the nitrogen-containing heterocyclic compounds (pyridines, pyrroles and indoles) showed an increased trend. Ulteriorly, a reaction pathway of main NCCs during co-pyrolysis process of FD and CH was proposed in this study. Additionally, the use of CaO catalysts reduced the content of CO2 and increased the contents of H2, CO and CH4 in non-condensable gas. Compared to CH-CaO, CA-CaO exhibited better catalytic performance for upgrading bio-oil.

The Hydration and Compressive Strength of Cement Mortar Prepared by Calcium Acetate Solution

Calcium acetate is the major component of the waste solution produced in treating recycled concrete aggregate (RCA) with acetic acid. Thus, the current work aims to explore the influence of calcium acetate solution on the performance of ordinary Portland cement. For this purpose, cement pastes and mortars were prepared using different concentrations, namely, 1, 2, and 3%, of calcium acetate solution. The heat evolution results confirmed that the calcium acetate solution at a concentration of 2% could accelerate the hydration of the cement. The XRD/TGA results and SEM images also indicated that more ettringite and calcium hydroxide (CH) are produced in the mortars prepared by the 2% calcium acetate solution. Moreover, the mortar containing the 2% calcium acetate solution has a denser microstructure than the control group according to the MIP tests results, and mortars cured for 3 and 28 days have a respective compressive strength, 23.34 and 15.43%, higher than the control group. The finding of this research could also contribute to studying the effect of adding metal ions to weakly acidic solutions as mixing liquids on the performance of cementitious materials.

Development and Validation of an Inductively Coupled Plasma Mass Spectrometry Method for Estimation of Elemental Impurities in Calcium Acetate Active Pharmaceutical Ingredient

A sensitive and selective method has been developed and validated for the simultaneous quantitative estimation of aluminum, magnesium, potassium, strontium and sodium in calcium acetate active pharmaceutical ingredient by inductively coupled plasma mass spectrometry. Inductively coupled plasma mass spectrometry is an advanced technique which is capable of analyzing multiple elements simultaneously with high selectivity, sensitivity and much lower detection limit. The test sample was prepared with microwave assisted acid digestion and introduced into optimized instrumental parameters for use of a quadrupole based Agilent 7800 inductively coupled plasma mass spectrometry instrument. Scandium is used as an internal standard in the study. The developed method was validated in terms of specificity, linearity, accuracy, precision, range, limit of detection, limit of quantitation and ruggedness. The results for recoveries of all elements were found between 85.3 to 103.9 %. The relative standard deviation for precision was within 15 %. Calibration plots were linear. The low relative standard deviation values and high recoveries of the method confirm the suitability of the method.

Dobijanje medicinskog tekstila na bazi viskoze i hitozana sa istovremeno poboljšanim sorpcionim i antibakterijskim svojstvima primenom dielektričnog barijernog pražnjenja

This study aimed to obtain textile based on viscose and chitosan with simultaneously improved sorption and antibacterial properties. For that reason, before functionalization with chitosan, the viscose fabric was modified by nonthermal gas plasma of dielectric barrier discharge (DBD) to introduce into its structure functional groups suitable for improved adsorption of chitosan. Functional groups' content of unmodified and DBD modified viscose fabric was determined by the calcium acetate method, while their influence on the surface charge, as well as the success of the functionalization of viscose fabrics with chitosan, was evaluated by measuring the zeta potential. Morphological, sorption and antibacterial properties of unmodified and DBD modified viscose fabrics, before and after functionalization with chitosan, were characterized by scanning electron microscopy, capillary rise method, and standard test method ASTME 2149-01: 2001, respectively. The obtained results showed that the treatment with DBD contributed to the simultaneous improvement of sorption and antibacterial properties of viscose fabric functionalized with chitosan, making it suitable for the production of high value-added medical textiles.

The elusive crystals of calcium acetate hemihydrate: chiral rods linked by parallel hydrophilic strips

The chance discovery of crystals of calcium acetate hemihydrate, which is commonly formed on calcareous heritage objects, has allowed its single crystal structure determination; this remarkable crystal structure consists of chiral rod-like units.

Adaptation of Calcium Acetate Methodology to Determine the Potential Acidity of Tropical Soils

ABSTRACT The determination of potential acidity (H+ Al) is of great importance to assess of the degree of soil fertility because of its direct application in the calculation of the cation exchange capacity. However, the direct method of determining H+ Al presents several problems, such as inaccuracy of titration and long time to perform the analysis. Our objective was to optimize the calcium (Ca) acetate method to make it faster, more accurate and capable of being applied on a large scale in routine analysis. The simplified method to obtain the value of H+ Al was based on reading the pH after extraction with Ca acetate, without the need for titration with sodium hydroxide. The contents of H+ Al were obtained in soil samples with varying contents of organic matter (OM) and H+ Al after extraction with either 0.5 mol L−1 Ca acetate or Shoemaker, McLean, and Pratt (SMP) buffer solution. The extraction of H+ Al was affected by the nature and concentration of the extraction solution, and OM contents in the soils. The simplified method of calcium acetate was able to predict the levels of H+ Al in the soil and has a high potential to be used on a large scale in laboratories.

Effect of Calcium Acetate Content on Apatite-Forming Ability and Mechanical Property of PMMA Bone Cement Modified with Quaternary Ammonium.

Polymethyl methacrylate (PMMA)-based bone cement is a popular biomaterial used for fixation of artificial joints. A next-generation bone cement having bone-bonding ability, i.e., bioactivity and antibacterial property is desired. We previously revealed that PMMA cement added with 2-(tert-butylamino)ethyl methacrylate, γ-methacryloxypropyltrimethoxysilane and calcium acetate showed in vitro bioactivity and antibacterial activity. This cement contains calcium acetate at 20% of the powder component. Lower content of the calcium acetate is preferable, because the release of a lot of calcium salt may degrade mechanical properties in the body environment. In the present study, we investigate the effects of calcium acetate content on the setting property and mechanical strength of the cement and apatite formation in simulated body fluid (SBF). The setting time increased and the compressive strength decreased with an increase in calcium acetate content. Although the compressive strength decreased after immersion in SBF for 7 d, all the cements still satisfied the requirements of ISO5833. Apatite was formed in SBF within 7 d on the samples where the calcium acetate content was 5% or more. Therefore, it was found that PMMA cement having antibacterial properties and bioactivity can be obtained even if the amount of the calcium acetate is reduced to 5%.

Hard to Soft: Biogenic Absorbent Sponge-like Material from Waste Mussel Shells

Summary Mussel shells are a source of renewable CaCO3 and can be obtained from aquaculture waste streams. Valorization of waste shells relieves strain on landfills and aligns with the goals of a circular economy. Here, we present the preparation of an absorbent CaCO3 material, soft calcite (SC), prepared from waste blue mussel shells under mild conditions. Calcite is the only polymorph present in SC, despite the presence of aragonite in the shell. SC has a nest-like morphology, unlike the highly ordered calcite in the shell. SC is formed by the reassembly of calcite prisms and may be held together by the organic matrix “glue” from the original shell as evidenced by NMR spectroscopy. This inorganic sponge adsorbs dyes from aqueous solution and absorbs crude oil from seawater with good recyclability. Our results demonstrate how a natural structure can be modified in a sustainable fashion to yield a higher-value material.

Comprehensive analysis of liposome formulation parameters and their influence on encapsulation, stability and drug release in glibenclamide liposomes

An understanding of the factors that affect liposome size, drug loading, stability and drug release is critical for the rational design of liposomes with desired pharmacokinetics and biodistribution. This article presents a report on the formulation and characterization of BIIB093 (glibenclamide) liposomes as well as a detailed analysis of the influence of formulation methods and parameters on encapsulation efficiency, liposome size, charge (zeta potential, ZP), polydispersity index (PDI), and drug release. PEGylated liposomes containing BIIB093 were made using ethanol injection and calcium acetate remote loading. The critical formulation parameters investigated include: the effect of lipid chain length, lipid unsaturation, lipid phase transition temperature (Tc) and the amount of cholesterol. Liposomes generated in this study had low average particle size (130 ± 20 nm), PDI (0.15 ± 0.1) and ZP (-2 ± 1 mV). Liposomes made from lipids with long acyl chains showed enhanced drug loading, encapsulation efficiency and drug retention. Similarly, liposomes made from lipids with high degree of unsaturation and low Tc exhibited faster drug release rates. Additionally, increasing the amount of cholesterol in the liposome bilayer improved PDI, decreased drug incorporation and accelerated drug release but had negligible impact on liposome size and ZP. Furthermore, encapsulating the drug in the liposome core enabled sustained drug release.