High Calcium Concentrations Research Articles

Behavior of heavy metals and natural radionuclides along the Moroccan phosphogypsum carbonation process with several alkaline reagents

Phosphogypsum (PG) is the main by-product from the phosphoric acid (PA) production industry being the PA production the basic raw material for producing the modern fertilizers. Because of its high calcium and sulfate content, it is important to emphasize that ecological benefits come from recycling and eventually converting PG into value-added compounds are obtained. This work aims to remedy the environmental problems associated to the large quantities of PG generated in Morocco. Furthermore, three procedures for PG conversion into Ca(OH)2, CaCO3, Na2SO4, K2SO4 and (NH4)2SO4 using hydroxide aqueous mediums were studied. The impurity traces contained in the PG were generally found to be completely transferred into the final calcite. The sulfates produced here are recommended for the use as a fertilizer (K2SO4 and (NH4)2SO4) and in the manufacture of detergents (Na2SO4), and the obtained calcite could be used in cement production, concretes, permeable reactive barriers for pollutants removing, etc.

Exploring the beneficial effects and mechanisms of Cerasus humilis (Bge.) Sok fruit for calcium supplementation and promotion

Cerasus humilis(Bge.) Sok (Ch) is a fruit-medicinal plant of the genus Cerasus and its fruits are rich in nutrition. Ch fruit is rich in mineral elements, organic acids, flavonoids and other components, especially the highest content of calcium in all fruits, so it is also known as “calcium fruit”. Calcium is an essential element in the human body and when calcium intake is insufficient, the body will directly lack the raw material of bone, which leads to bone diseases such as osteoporosis. In this study, the contents of elements, total polyphenols and total flavonoids in Ch fruit were determined. The effect of Ch fruit in calcium supplementation and promotion of calcium absorption were investigated and the results showed Ch regulates the changes of DHVD3, CT, I-PTH, and ALP, resulting in an improvement in bone calcium content and density. Meanwhile, Ch fruit promotes intestinal calcium absorption through the transmembrane transport pathway. Further molecular docking study found that flavonoids such as quercetin-3-O-glucoside, quercetin-3-O-glucoside, and cyanidin-3-glucoside are likely to contribute to this mechanism. In summary, this study confirmed the calcium supplement and promotion of calcium absorption of Ch fruit and preliminarily identified the calcium promoting mechanism and its material basis. These findings shed light on the potential use of Ch fruit as a dietary supplement to improve bone health.

PRE-TREATMENT OF VEGETABLES AND FORMULA DEVELOPMENT OF CALCIUM-FORTIFIED VEGETABLE CRISPY WAFFLES WITH RICEBERRY USING A MIXTURE DESIGN

Crispy waffles are popular snacks typically containing wheat flour, sugar, and oil. Excessive consumption may be unhealthy. This study aimed to produce healthier crispy waffles using vegetables, specifically Chinese kale (CK), False Pak Choi (FPC), and Thai basil (TB), as sources of calcium. These vegetables underwent three pre-treatments: blanching, steaming, and stir-frying. The study then focused on the formulation of calcium-fortified crispy vegetable waffles with riceberry (CVWR) using a mixture design experiment. Calcium content in TB, FPC, and CK was found to be 313.96, 309.88, and 246.15 mg/100g, respectively. Pre-treatment results revealed that steaming resulted in the least reduction of calcium content, while stir-frying caused the least reduction of total chlorophyll and total polyphenol contents. The proportions of the crispy waffles components were 0-30%CK, 0-30% FPC, 0-30%TB, and 70% riceberry. The physical quality of CVWR, considering crispness and calcium content, was determined using a linear regression equation. The analysis showed that CVWR with TB as the primary component had the highest calcium content and crispness, followed by FPC and CK, respectively. In terms of sensory characteristics, FPC had the highest fracture coefficient, followed by TB and CK, respectively. The optimal formulation, determined by overlapping diagrams, consisted of 14.88% FPC, 13.11% TB, 2.01% CK, and 70% riceberry. The resulting CVWR contained 286.19 mg/100g calcium and was a source of total dietary fiber and anthocyanin. Consequently, CVWR offers a healthier, high-nutritional-value snack option suitable for health-conscious consumers.

Calcium Phosphate Treatment Enhances Osteogenic Differentiation of Porcine Adipose-Derived Stem Cells on Fibrin Scaffolds

This study was designed to develop a fibrin scaffold for optimum in vitro osteogenic differentiation of porcine ASCs. Fibrin scaffolds physically and chemically modified to be stiffer or have higher concentrations of calcium and phosphate ions were hypothesized to enhance osteogenic differentiation compared to control fibrin scaffolds. Treatments during coagulation resulted in six scaffold types for comparison: whole blood controls, red blood cell lysis buffer, calcium chloride, calcium hydrogen phosphate, vacuum, and mechanical compression. Based on the results, fibrin supplemented with granules of calcium hydrogen phosphate (CaHPO4) was determined to be the most suitable formulation of those examined. Using calcium phosphate resulted in a fibrin scaffold that coagulated faster (p = 0.022), had a rougher surface, higher stiffness, and desirable properties for practical use during surgical operations and scaffolds used in bone tissue engineering. Further, osteogenic differentiation was enhanced on scaffolds treated with calcium phosphate. In addition, fibrin scaffolds treated with RBC lysis buffer were also stiffer than untreated controls. These results are partly explained by ASC attachment and fibrin polymerization during coagulation.

Thymus satureioides Coss.: Mineral Composition, Nutritional Value, Phytochemical Profiling, and Dermatological Properties.

Zaitra, Thymus satureioides, is an aromatic plant with a long history of use in traditional medicine. In this study, we assessed the mineral composition, nutritional value, phytocontents, and dermatological properties of the aerial parts of T. satureioides. The plant contained high contents of calcium and iron, moderate levels of magnesium, manganese, and zinc, and low contents of total nitrogen, total phosphorus, total potassium, and copper. It is rich in several amino acids, including asparagine, 4-hydroxyproline, isoleucine, and leucine, and the essential amino acids account for 60.8%. The extract contains considerable amounts of polyphenols and flavonoids (TPC = 118.17 mg GAE/g extract and TFC = 32.32 mg quercetin/g extract). It also comprises 46 secondary metabolites, identified through LC-MS/MS analysis, belonging to phenolic acids, chalcones, and flavonoids. The extract elicited pronounced antioxidant activities, inhibited the growth of P. aeruginosa (MIC = 50 mg/mL), and reduced biofilm formation by up to 35.13% using the ¼ sub-MIC of 12.5 mg/mL. Moreover, bacterial extracellular proteins and exopolysaccharides were diminished by 46.15% and 69.04%, respectively. Likewise, the swimming of the bacterium was impaired (56.94% decrease) in the presence of the extract. In silico, skin permeability and sensitization effects revealed that out of the 46 identified compounds, 33 were predicted to be exempt from any skin sensitivity risk (Human Sensitizer Score ≤ 0.5), while extensive skin permeabilities were observed (Log Kp = -3.35--11.98 cm/s). This study provides scientific evidence about the pronounced activities of T. satureioides, supports its traditional uses, and promotes its utilization in the development of new drugs, food supplements, and dermatological agents.

Adsorption of antibiotics on bio-adsorbents derived from the forestry and agro-food industries

Antibiotic consumption at high levels in both human and veterinary populations pose a risk to their eventual entry into the food chain and/or water bodies, which will adversely affect the health of living organisms. In this work, three materials from forestry and agro-food industries (pine bark, oak ash and mussel shell) were investigated as regards their potential use as bio-adsorbents in the retention of the antibiotics amoxicillin (AMX), ciprofloxacin (CIP) and trimethoprim (TMP). Batch adsorption/desorption tests were conducted, adding increasing concentrations of the pharmaceuticals individually (from 25 to 600 μmol L−1), reaching maximum adsorption capacities of ≈ 12000 μmol kg−1 for the three antibiotics, with removal percentages of ≈ 100% for CIP, 98–99% adsorption for TMP onto pine bark, and 98–100% adsorption for AMX onto oak ash. The presence of high calcium contents and alkaline conditions in the ash favored the formation of cationic bridges with AMX, whereas the predominance of hydrogen bonds between pine bark and TMP and CIP functional groups explain the strong affinity and retention of these antibiotics. The Freundlich's model provided the best prediction for AMX adsorption onto oak ash and mussel shell (heterogeneous adsorption), whereas the Langmuir's model described well AMX adsorption onto pine bark, as well as CIP adsorption onto oak ash (homogeneous and monolayer adsorption), while all three models provided satisfactory results for TMP. In the present study, the results obtained were crucial in terms of valorization of these adsorbents and their subsequent use to improve the retention of antibiotics of emerging concern in soils, thereby preventing contamination of waters and preserving environment quality.

Triggered heavy metals and chlorine simultaneous removal from hazardous waste incineration fly ash

To date, heavy metals and chlorine removal from hazardous waste incineration fly ash (HWI FA) by thermal treatment was scarcely reported. High content of calcium in HWI FA might affect heavy metals chlorination volatilization. The aim of this study was to realize heavy metals and chlorine simultaneous removal from HWI FA triggered by fluidized-bed municipal solid waste incineration fly ash (FBMSWI FA) during sintering. Results showed that the dilemma of low heavy metals removal efficiency was due to the dense structure and the difficulty of transformation of the stable phases including Cu2S, CuSiO3, and Zn2SiO4. By co-sintering with FBMSWI FA at the ratio of 1:1, the removal efficiency of Cu, Zn, Pb, Cd, and Cl reached as high as 84.4%, 92.0%, 99.9%, 99.5%, and 99.7%, respectively. Compared with the control, chlorination volatilization efficiency of Cu and Zn was significantly increased by 210.5% and 89.2%. The favourable promotion could be mainly attributed to Si/Al matrix in FBMSWI FA triggered the following reaction: i) Ca-bearing compounds in HWI FA were activated to destroy the dense structure, which facilitated the transformation of Cu2S to CuO; and ii) the conversion of NaCl and KCl to gaseous chlorine was promoted, which the formation of metal chlorides was accelerated.

Mechanism of CaO in Light-Burned Magnesia on the Formation Process, Mechanical Properties, and Water and Chloride Resistance of the 517 Phase

With the continuous exploitation of high-quality magnesite ores, a large number of low-grade magnesite ores with high calcium contents were abandoned, thereby occupying the land, polluting the environment, and causing substantial resource waste. Therefore, resource utilization of low-grade magnesite ores is urgently needed. These low-grade magnesite ores can be used by calcination to prepare raw materials of magnesium oxysulfate (MOS) cement, but CaO could be produced during calcination because dolomite is a dominant mineral. Therefore, this paper mainly studied how CaO affects the formation process, mechanical properties, and water and chloride resistance of the pure 517 phase. Light-burned dolomite (LBD) was used to offer CaO, replacing a certain amount of light-burned magnesia (LBM) in this work. It was found that CaO will react with Mg2+ and SO42− to form an amorphous phase that remains stable when curing in air but unstable when immersing in water. When immersed in water, Ca2+ would continue to react with SO42− to precipitate gypsum, thus destroying the original structure and reducing the stability of the pure 517 phase. Therefore, in the preparation of MOS cement, attention should be given to the content of CaO, and modifiers should be added to obtain a low solubility calcium compound to reduce the negative effects of CaO on MOS cement.

The Application of Eggshell and Fruit Peels as Soil Amendment on The Growth Performance and Yield of Corn (Zea mays L.)

Organic materials from processed crops and animals can be applied to enhance soil fertility. Kitchen waste such as eggshell and fruit peels contained macro and micronutrient that are essential for plant growth and development. This research focuses on investigating the effects of eggshell powder and fruit peel as a soil amendment on the growth performance and yield of maize. Ground eggshell and different fruit peels such as banana, orange and pomegranate were mixed to produce a soil amendment. The experiment consists of four treatments; T1 (control), T2 (eggshell powder), T3 (fruit peels) and T4 (eggshell powder + fruit peels) with three replications arranged in RCBD. The overall growth performance increased throughout the planting period. The highest maize yield was recorded in T4 at 452.15 g. The soil pH in T3 and T4 increased from slightly acidic to neutral in the range of pH 7.44 to 7.51. This results from the high calcium content in the eggshell and phosphorus as well as potassium content in the fruit peels. This study proves that the eggshell and fruit peel can be feasibly used as a soil amendment and pH regular for improving and sustaining soil nutrient level thus fertility.

Chemical Characteristics and Plant Growth Regulators of Organic Waste as Liquid Organic Fertilizer

Abundant agricultural waste could be used to improve plant growth. This study was to obtain the nutrient characteristics and plant growth regulators (PGR) of organic waste (eggshells, banana peels, moringa leaves, onion peels, bean sprouts, and banana hump) which have the potential as liquid organic fertilizer (LOF). This research was conducted from July to August 2022 using a descriptive-analytic method. Organic waste was fermented anaerobically. The results showed that nitrogen content in banana peels, moringa leaves, onion peels, bean sprouts, and banana hump required the LOF standard (3-6%) and had the potential to be applied. In addition, eggshells had the highest calcium content (0.149%) compared to other organic wastes. Among the organic wastes, it was found that banana hump, moringa leaves, and onion peels had the highest PGR levels.

A two-step green liquid-liquid extraction strategy for selective lithium recovery and application to seawater

Efficiently harvesting lithium from seawater remains a challenge due to the extremely dilute concentration of lithium ions (Li+) and the existence of many foreign metal ions that are far more abundant. Here, a hydrophobic deep eutectic solvent (HDES)-based two-step liquid-liquid extraction (LLE) strategy is developed for the first time that realizes the separation of dilute Li+ (<1 mg/L) from solutions with a high concentration of sodium, potassium, magnesium and calcium ions. This strategy contains the removal of divalent cations and selective recovery of Li+, which minimizes the influence of coexisting metal ions. In the first LLE step, the unwanted divalent cations are removed with a negligible loss of Li+ by the bis(2-ethylhexyl)phosphate/kerosene (DEHPA/KERO) system. Then, the DEHPA/HDES system can selectively extract Li+ from monovalent cations. All solvents used are readily available and low cost with methyltrioctylammonium chloride and decanoic acid at a 1:2 mol ratio (N8881Cl/2DecA) as the main extractant. Extraction equilibrium is reached within 10 s. The single extraction efficiency of Li+ is 66.4%, and the separation coefficient of lithium and sodium (βLi/Na) reaches 11.6 at the optimized extraction conditions. Finally, the proposed two-step LLE strategy is applied to the simulated seawater. The extraction performance of N8881Cl/2DecA-DEHPA was not significantly weakened after being reused ten times.

Characteristics of Bioceramic Hydroxyapatite Based on Sand Lobster Shells (&lt;i&gt;Panulirus homarus&lt;/i&gt;) as Sources of Calcium with Optimal Calcination Temperature

In this work, bioceramic hydroxyapatite (HAp) was synthesized based on sand lobster shells (Panulirs homarus) as a source of calcium using the precipitation method. Sand lobster shell powder was calcinated with temperature variations of 600, 800, and 1000 °C for 6 hours. The effect of calcination temperature on sand lobster shell powder was characterized to determine the optimal temperature for the synthesis of HAp. Based on the XRF (X-Ray Fluorescence) characterization, the highest calcium content (Ca) was 93% at a calcination temperature of 1000 oC. This result was supported by FTIR (Fourier Transform Infrared) spectrum that increasing the calcination temperature will reduce the intensity of carbonate ion (CO32-). These results showed that 1000 °C was the best calcination temperature on sand lobster shells to synthesize HAp. The characterization result of HAp using EDX (Energy Dispersive X-Ray) revealed that the molar ratio of Ca/P was 1.73. The FTIR and XRD (X-Ray Diffractometer) spectral pattern indicate that HAp had been successfully synthesized with minor-TCP, which is also a calcium phosphate with high biocompatibility.

Experimental investigation on the mechanical performance and microscopic characterization of desulfurization gypsum-reinforced ternary geopolymer

Alkali-activation geopolymer material has been widely studied and applied in engineering due to its advantages of energy conservation and environmental protection. The geopolymer with the ground granulated blast-furnace slag (GGBS) and fly ash (FA) is the most common. This paper is aimed to incorporate the flue gas desulfurization gypsum (DG) into the GGBS/FA geopolymer to form a new ternary geopolymer. Thus, the unconfined compression tests are carried out to study the effects of the variations of GGBS and DG content and modulus of alkali activator on the compressive strength, then X-ray diffraction (XRD) and scanning electron microscope (SEM) are performed to analyze the chemical components of final products and microstructures to reveal the strength composition mechanism. Results show that the presence of calcium in GGBS and DG contributes to the C-(A)-S-H products while the polymerization reaction is impeded. The incorporation of DG can combine with active silicate to generate ettringite and fill the pores inside the geopolymer. In addition, the SO42- in DG can also promote the polymerization reaction. The double role of the above effects improves the strength of geopolymer. The lower alkaline condition leads to lower compressive strength due to the less polymerization gel products, while the contribution of high calcium content to the strength improvement is more pronounced. However, the DG content should be controlled to prevent the volume-filling effect and the produced ettringite shows excessive volume expansion.

Sustainable cement replacement using waste eggshells: A review on mechanical properties of eggshell concrete and strength prediction using artificial neural network

Though the European Commission classifies eggshell as a hazardous material, using eggshell powder in place of cement can aid in waste reduction and contribute to sustainability initiatives. Eggshell powder replaces cement in concrete manufacturing due to its high calcium content. Eggshell is impermeable in nature, so it helps in reducing the permeability of concrete. Eggshell powder fastens the process of hydration of cement by the formation of monocarboaluminate during the mixing of material at the time of casting. This paper includes a detailed study of the process production of eggshell powder, the properties of eggshell powder concrete, and the relationship between different properties has been determined. In addition, Artifical Neural Network approach has been used to predict the strength of eggshell powder concrete to reduce the labour cost and experimental time. In the end, microstructure of eggshell powder and its application in various engineering products have been reviewed. After analyzing the qualities of eggshell powder concrete, it was determined that replacing up to 20% of the cement in concrete with eggshell powder increases the material's strength. The ANN model's results also demonstrate its effectiveness in forecasting the strength of eggshell powder concrete, with an R2 value of 0.96. So, it clearly shows that eggshell powder can be used to replace cement to improve the properties of concrete and reduce the percentage of cement usage. Finally, the conclusions and discussion of this study addressed the eco-friendly utilization of eggshell powder in construction applications.

THE EFFECT OF STARTER RATIO ON TOFU-PROCESSING WASTEWATER FERMENTATION INTO FERTILIZER

The process of tofu manufacturing produces solid (slurry) and liquid wastes with high protein content. Tofu-processing Wastewater can be used as the primary material for liquid NPK fertilizer production. The process of converting tofu-processing wastewater into liquid fertilizer was simple and requires a short fermentation time. The fermentation process was carried out by mixing of EM 4 (starter for fermentation liquid), alcohol as solvent and organics matter. The selection of organic matter that is used as the primary ingredient of liquid fertilizer would affect the content of N, P and K substances in the product. Banana peel and cabbage are organic matter with a high calcium and phosphorus content. This research was conducted to determine the effect of the addition ratio of cabbage and banana peel to time duration of fermentation on the tofu- wastewater processing into liquid fertilizer. The results showed that increasing the ratio of cabbage to the starter increased the levels of N and P along with the length of fermentation time. However, increasing the cabbage ratio in the starter causes a decrease of K in liquid fertilizer.

22. The Role of Orai1 in Osteogenic Differentiation Induced by Nanoparticulate Mineralized Collagen Glycosaminoglycan Materials

PURPOSE: Development of synthetic regenerative materials inspired by the extracellular matrix (ECM) has been a topic of significant interest due to the known properties of the ECM to direct cell fate determination via tunable material composition and biomechanical properties. Nanoparticulate mineralized collagen glycosaminoglycan (MC-GAG) is a low density, open-cell foam that has been evaluated in our laboratory to induce osteogenic differentiation of primary osteoprogenitors in vitro as well as regeneration of rabbit skull defects in vivo without pre-seeding with progenitor cells or addition of exogenous growth factors, which was not observed in non-mineralized collagen glycosaminoglycan (Col-GAG) materials. Given that the critical difference between MC-GAG and Col-GAG is the mineral content, the spatial concentration of inorganic ions on MC-GAG may be critical to its osteogenic properties. This is supported by prior research demonstrating that high calcium concentrations in the bone microenvironment stimulate osteoblastic differentiation. How these biochemical cues are transmitted to cells and activate downstream osteogenic signaling pathways should be further elucidated. Orai1 is a critical subunit of store-operated calcium release-activated calcium channels (CRAC) that has been implicated to be involved in bone homeostasis. In this work, we evaluated the contribution of Orai1 to MC-GAG-mediated osteogenesis. METHODS: To examine the role of extracellular calcium signaling through store-operated calcium channels, such as Orai1, on osteogenic differentiation of primary bone marrow-derived human mesenchymal stem cells (hMSCs), we treated 2D cell cultures with a small molecule inhibitor of store-operated calcium entry (SOCE), MRS1845, for 14 days. hMSCs were subsequently seeded on MC-GAG or Col-GAG for 7 days with or without MRS1845. Baseline Orai1 gene and protein expression was evaluated. Next, small interfering RNAs (siRNAs) targeting ORAI1 and a scrambled control were used to specifically knockdown ORAI1 expression in hMSCs cultured on Col-GAG and MC-GAG. Osteogenic gene and protein expression were measured using quantitative RT-PCR and western blot analyses, respectively. Mineralization was evaluated by Alizarin Red staining. RESULTS: To understand whether store-operated calcium entry was essential to osteogenic differentiation, we treated hMSCs in 2D cultures with a small molecule inhibitor of SOCE, MRS1845, and found a reduction in calcium depositions visualized with Alizarin Red staining when compared to untreated hMSCs. In 3D cultures, MRS1845 downregulated the gene expression of early osteogenic marker ALP and protein expression of the intracellular osteogenic mediator Runx2 specifically on MC-GAG compared to controls. As small molecule inhibitors lack channel specificity, we knocked down ORAI1 expression through siRNA transfection. When MC-GAG was compared with Col-GAG, baseline ORAI1 gene expression was 1.8-fold higher (p=0.02) and Orai1 protein expression was upregulated (p=0.003). ORAI1 knockdown reduced the protein expression of Runx2 and gene expression of late osteogenic marker BSP2 specifically on MC-GAG compared to scrambled control siRNA. Mineralization significantly diminished on MC-GAG with ORAI1 knockdown, whereas no effects were evident on Col-GAG as demonstrated by Alizarin Red staining. CONCLUSIONS: ORAI1-mediated calcium ion signaling was required for MC-GAG-induced osteogenic differentiation. Further elucidation of the osteogenic mechanisms and refinement of calcium levels on MC-GAG may facilitate its clinical application in the reconstruction of osseous defects.

Genome-wide analysis of the cellulose toolbox of Primulina eburnea, a calcium-rich vegetable

BackgroundHuman-guided crop domestication has lasted for more than 10,000 years. In terms of the domestication and breeding of vegetables, cellulose content in edible tissues is one of the most important traits. Primulina eburnea is a recently developed calcium-rich vegetable with a high soluble and bioavailable calcium content in its leaves. However, the high cellulose content in the leaves hampers the taste, and no research has been reported on the genetic basis of cellulose biosynthesis in this calcium-rich vegetable.ResultsWe identified 36 cellulose biosynthesis-involved genes belonging to eight gene families in the P. eburnea genome. The cellulose accumulated decreasingly throughout leaf development. Nineteen genes were considered core genes in cellulose biosynthesis, which were highly expressed in buds but lowly expressed in mature leaves. In the nitrogen fertilization experiment, exogenous nitrogen decreased the cellulose content in the buds. The expressing pattern of 14 genes were consistent with phenotypic variation in the nitrogen fertilization experiment, and thus they were proposed as cellulose toolbox genes.ConclusionsThe present study provides a strong basis for the subsequent functional research of cellulose biosynthesis-involved genes in P. eburnea, and provides a reference for breeding and/or engineering this calcium-rich vegetable with decreased leaf cellulose content to improve the taste.

Can we reverse arterial stiffness by intervening on CKD-MBD biomarkers?

The increased cardiovascular risk of chronic kidney disease may in part be the consequence of arterial stiffness, a typical feature of kidney failure. Deranged homeostasis of minerals and hormones involved (CKD-MBD), are also strongly associated with this increased risk. It is well established that CKD-MBD is a main driver of vascular calcification, which in turn worsens arterial stiffness. However, there are other contributors to arterial stiffness in CKD than calcification. An overlooked possibility is that CKD-MBD may have detrimental effects on this potentially better modifiable component of arterial stiffness. In this review, the individual contributions of short-term changes in calcium, phosphate, PTH, vitamin D, magnesium, and FGF23 to arterial stiffness, in most studies assessed as pulse wave velocity, is summarized. Indeed, there is evidence from both observational studies and interventional trials that higher calcium concentrations can worsen arterial stiffness. This, however, has not been shown for phosphate, and it seems unlikely that, apart from being a contributor to vascular calcification and having effects on the microcirculation, phosphate has no acute effect on large artery stiffness. Several interventional studies, both by infusing PTH and by abrupt lowering PTH by calcimimetics or surgery, virtually ruled out direct effects on large artery stiffness. A well-designed trial using both active and nutritional vitamin D as intervention found a beneficial effect for the latter. Unfortunately, the study had a baseline imbalance and other studies did not support its finding. Both magnesium and FGF23 do not seem do modify central arterial stiffness.

Elevated dissolved carbon dioxide and associated acidification delays maturation and decreases calcification and survival in the freshwater crustacean Daphnia magna

AbstractIncreasing pCO2 in freshwaters across the globe will likely be accompanied by acidification. Although this has been linked to reduced calcification, growth, and survival in several marine species, similar responses in freshwater organisms remain largely unexplored. Here, we investigated the direct effects of elevated pCO2 and associated acidification on the water flea Daphnia magna. As a highly efficient filter feeder, this crustacean is a dominant primary consumer in freshwater zooplankton assemblages, capable of controlling algal growth. It has a high calcium content compared to other zooplankton species, which might make it particularly sensitive since calcification may be impaired under elevated pCO2. We exposed newly hatched individuals of four clonal lineages to 27,000 ppm pCO2 corresponding to a pH of 6.7 in a controlled laboratory experiment. Both survival and calcium content were reduced and juveniles grew slower and matured later under elevated pCO2. Adult growth rate was not affected by pCO2 suggesting that surviving adults are less sensitive or may acclimate over time but at the cost of reduced offspring size. We hypothesize that the combination of elevated pCO2 and low pH interferes with the calcification process, reflected in slower growth, smaller body size and reduced calcification in D. magna. In turn, this might lead to less efficient control of phytoplankton as an ecosystem service and reduce their competitive advantage over other zooplankters with less calcified bodies.

Evaluation of Remineralization Potential of Natural Substances on Artificially Induced Carious Lesions in Primary Teeth: An In Vitro Study.

To evaluate the remineralizing potential of natural substances on artificially induced caries lesions in primary teeth. A total of 50 primary molar teeth were selected and subjected to a demineralization process. Then samples were randomly divided into five groups for the remineralization process. Group I-colophony, group II-5% sodium fluoride (NaF) + colophony, group III-grape seed extract (GSE) + colophony, group IV-5% NaF + colophony + 10% peptide, and group V- GSE + colophony + 10% peptide. All the groups were subjected to remineralization using a brushing stimulator for 3,000 cycles. Assessment was done using Vickers hardness testing machine for evaluating the enamel surface microhardness (SMH) and scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) for evaluating the surface morphology and mineral content, before and after demineralization and after remineralization, the obtained data was analyzed statistically using IBM Statistical Package for the Social Sciences (SPSS) software version 25. The enamel microhardness results of this study revealed that remineralization of enamel was highest in group V (212.83 ± 64.416) and least in group II (137.83 ± 26.324) p-value of 0.038. SEM-EDX analysis revealed high calcium (Ca) and fluoride (F) content in groups II and IV, which was significant (p-value of 0.001) from other groups. Surface morphology evaluated with SEM revealed spherical globular agglomerates and scaffolding deposits on the enamel surface in groups III and V resembling the remineralization process. Grape seed extract (GSE) with colophony and peptide is a superior natural alternative to NaF. Colophony also exhibited remineralizing potential in primary enamel. Natural remineralizing agents like GSE, colophony, and its combination serves as a potential alternative to overcome the toxic effect on long-term usage of F. These natural substances can be applicable in clinical conditions by incorporating toothpaste and varnish, which can be used as an alternative or adjuvant to the topical application of F. Pooja V Ravi, Rajakumar S, Kavitha Ramar. Evaluation of Remineralization Potential of Natural Substances on Artificially Induced Carious Lesions in Primary Teeth: An In Vitro Study. Int J Clin Pediatr Dent 2023;16(2):244-250.