Calcium Carbonate Research Articles

Oligopeptide modified ICG/Cisplatin@CaCO3 for targeted osteosarcoma NIR-II imaging guided multimodal therapy

Osteosarcoma, as the most prevalent primary malignant bone tumor, has consistently shown suboptimal clinical treatment outcomes. In this manuscript, we proposed an efficacious and novel phototherapy strategy for osteosarcoma based on a photoresponsive near-infrared (NIR) material, CaCO3-ICG-DDP-PEG-PT (CIDP-PT), which contained calcium carbonate (CaCO3) and Cisplatin (DDP) via the gas dispersion method, and indocyanine green (ICG) was encapsulated through a nanoprecipitation reaction by employing DSPE-PEG2000-COOH to enhance the stability and hydrophilicity. The targeting oligopeptide (PT) for osteosarcoma cells was inserted into the outer membrane of nanoparticles, thereby further enhancing the tumor-targeting capability through receptor-mediated binding. The prepared CIDP-PT nanoparticles exhibited high targeting efficiency and multifunctionality. In vitro and in vivo experiments demonstrated that CIDP-PT significantly enhanced the therapeutic efficacy for osteosarcoma via the NIR-II photoresponsive and tumor-targeting approach. It achieves efficient tumor cell eradication through multiple modalities while maintaining an exceptional level of biocompatibility. Hence, the CIDP-PT nanocarriers possess considerable practical value for future clinical applications in adjunct osteosarcoma phototherapy.

The change of physical properties of calcium carbonate nanomaterials cured soil in road substrates

The utilization of appropriate materials to enhance road subgrade’s physical characteristics is crucial for current transportation construction and maintenance. This study proposes a curing method that employs calcium carbonate nanomaterials to address the problem of soil displacement and settlement in roadway subgrades. A method was developed during the study to explore the optimal curing material ratio. Additionally, this study developed a method for testing and analyzing the mechanical properties of soils cured with nanomaterials, including measures of tensile stress, triaxial shear stress, and Moore’s damage envelope. The study demonstrated that the unconfined compressive strength of the soil treated with calcium carbonate nanomaterials was 0.40 MPa after 7 days of curing with a 6% doping of the curing agent. Increasing the doping to 18% resulted in a breaking load of the soil reaching 0.100 kN. Furthermore, the triaxial shear stress–strain curve of the soil exhibited a slope of 264.47 during the linear phase when the curing agent was dosed at 6%. The slope of the linear phase of the stress–strain curve for triaxial shear at 6% curing agent doping was found to be 264.47. The cured soil molar pack line exhibited an internal friction angle of 22.66 degrees at the same curing agent dosage. The displacement analysis of the replacement roadbed with cured soil revealed a maximum observed displacement of only 377 mm after filling the embankment using the study method. The experimental results provide support for the hypothesis of the study, which suggests that the application of calcium carbonate nanoparticles can significantly enhance the physical characteristics of road subgrade.

Comparative Performance of Unmodified and SBS-Modified Asphalt Mixtures Made with Blowdown (CarSul) and Calcium Carbonate as Mineral Fillers

Comparative Performance of Unmodified and SBS-Modified Asphalt Mixtures Made with Blowdown (CarSul) and Calcium Carbonate as Mineral Fillers

Applicability of electrical resistivity measurements for monitoring biocementation treatment in soils

In this paper the use of ER measurements in soils in the context of biocementation, is investigated considering its use as an indicator of treatment efficiency measured trough the presence of biocement, or to provide information about the presence of chemical by-products during or after final washing operations. The electrical resistivity of a slightly biocemented sand was analyzed on a laboratory scale test conceived to reproduce field measurements conditions such as varying degrees of saturation and the presence of chemical by-products in the pore fluid. The results confirmed that, independently from the degree of saturation, the nature of the pore fluid was the parameter that affected most the electrical resistivity measurements, and the presence of calcium carbonate affecting soil structure was detected only after removal of the treatment by-products by a complete final soil washing using water. From a practical point of view this non-destructive technique is more adequate to be used mainly at the end of the treatment, to check that complete soil washing has occurred, rather than checking the presence of bio-cement specially if the amount precipitated is not very high as it was the case of the tests performed.

An Experimental Investigation on Mechanical Properties of Bacterial Concrete Using Bacillus Subtilis

Abstract: This Concrete is susceptible to micro crack formation and has pores which are highly undesirable because they provide an open pathway for the ingress of water and other deleterious substances. The use of concrete surface treatments with water proofing materials to prevent the access of aggressive substances is a common way of contributing to concrete durability. However, the most common surface treatments use organic polymers (epoxy, acrylics and polyurethanes) all of which have some degree of toxicity. Bio inspired materials can lead to a more sustainable construction industry, especially when providing new low toxic solutions. Hence, there is an urgent need to pay more attention for improving the properties of concrete with respect to strength and durability, especially in aggressive environments. One effective remedy for closure of cracks is the Bacterial Concrete (BC) which will continuously deposit calcite in concrete. This, phenomenon is called as Microbiologically Induced Calcite Precipitation (MICP). The urease enzyme enables the deposition of calcium carbonate (CaCO3) with the help of bacteria. The bacterial remediation technique surpasses other techniques as it is bio-based, eco-friendly and durable. Bacteria need to offer resistance to withstand high pH of concrete and mechanical stresses during mixing. In these present investigations bacterial sample name Bacillus Subtilis (BS) is considered in concentrations of 104 , 105 and 106 cells/ml of mixing of water. investigations are carried out on strength-related properties such as compressive strength, splitting tensile strength and flexural strength to assess the quality of concrete. The optimum dosage of cell concentration of bacteria is found to be 105 cells/ml for BS based on compressive strength results. M25 grade concrete is designed and used for embedding Bacillus subtilis bacteria.

Molecular Weight-Dependent Physiochemical Behaviors of Calcium Carbonate Chains.

The regulation of physiochemical behaviors by changing molecular weights is an important cornerstone of polymer physics. However, similar correlations between molecular weights and properties have not been discovered in inorganic ionic compounds. In this work, we prepared a calcium carbonate specimen with a semiflexible chain topology analogous to those of polymers. The molecular weights of the calcium carbonate chains, which ranged from 3400 to 54 100 Da, were directly correlated to their physiochemical behaviors, including gel point, zero shear viscosity, and plateau modulus. The calcium carbonate chains showed similar polymeric characteristics, including shear thinning, thixotropy, entropic elasticity, and viscoelasticity. These features agreed with recent theories and formulas in polymer physics textbooks. On the basis of this understanding, the mechanical properties of calcium carbonate-based gels could be altered by changing their molecular weights. This study could represent a fusion of inorganic chemistry and polymer physics with similar molecular weight-dependent behaviors and material properties, establishing an alternative pathway for designing future inorganic materials.

Application of microbially induced calcium carbonate precipitation (MICP) process in concrete self-healing and environmental restoration to facilitate carbon neutrality: a critical review.

Soil contamination, land desertification and concrete cracking can have significant adverse impacts on sustainable human economic and societal development. Cost-effective and environmentally friendly approaches are recommended to resolve these issues. Microbially induced carbonate precipitation (MICP) is an innovative, attractive and cost-effective in situ biotechnology with high potential for remediation of polluted or desertified soils/lands and cracked concrete and has attracted widespread attention in recent years. Accordingly, the principles of MICP technology and its applications in the remediation of heavy metal-contaminated and desertified soils and self-healing of concrete were reviewed in this study. The production of carbonate mineral precipitates during the MICP process can effectively reduce the mobility of heavy metals in soils, improve the cohesion of dispersed sands and realize self-healing of cracks in concrete. Moreover, CO2 can be fixed during MICP, which can facilitate carbon neutrality and contribute to global warming mitigation. Overall, MICP technology exhibits great promise in environmental restoration and construction engineering applications, despite some challenges remaining in its large-scale implementation, such as the substantial impacts of fluctuating environmental factors on microbial activity and MICP efficacy. Several methods, such as the use of natural materials or wastes as nutrient and calcium sources and isolation of bacterial strains with strong resistance to harsh environmental conditions, are employed to improve the remediation performance of MICP. However, more studies on the efficiency enhancement, mechanism exploration and field-scale applications of MICP are needed.

Monitoring Land Management Practices Using Vis–NIR Spectroscopy Provides Insights into Predicting Soil Organic Carbon and Limestone Levels in Agricultural Plots

This study aimed to establish sound relationships between soil properties of agricultural land in central Spain and their spectral attributes to contribute to deriving an indicator for sustainable farm management. Sixteen plots, managed under various conditions, eight with traditional tillage and eight with other alternative managements, were selected to gather soil samples representing three predominant soil orders (Leptosols, Cambisols, and Luvisols). Soil sampling was conducted from depths ranging from 0 to 30 cm (0–50; 5–10, 10–20, and 20–30 cm), ensuring a broad spectrum of sample variability across different times and locations. The reflectance of soil 64 soil samples was measured within the range of 400 to 900 nm, and the corresponding concentrations of soil organic carbon and majoritarian minerals, calcium carbonate, quartz, phyllosilicates, K-Feldspar, and plagioclase were determined for each sample. Partial least squares analysis was employed to construct prediction models using a calibration dataset comprising 66% of randomly selected samples. The remaining 33% of samples were utilized for model validation. The prediction models for the measured soil chemical properties yielded R2 values ranging from 0.14 to 0.79. Only SOC and limestone provided accurate prediction models. These findings hold promise for developing a soil health indicator tailored for site-specific crop management. However, the complex composition of soil organic carbon and calcium carbonate in certain soils underscores the importance of careful interpretation and validation of remote sensing data, as well as the need for advanced modeling approaches that can account for the interactions between multiple soil constituents.

Leaching and cytotoxicity of bismuth oxide in ProRoot MTA - A laboratory investigation.

The present study examined the leaching and cytotoxicity of bismuth from ProRoot MTA and aimed to identify whether bismuth leaching was affected by the cement base and the immersion regime used. The leaching profile of bismuth was examined from ProRoot MTA and compared with hydroxyapatite containing 20% bismuth oxide as well as hydroxyapatite and tricalcium silicate to investigate whether bismuth release changed depending on the cement base. Bismuth leaching was determined after 30 and 180 days of ageing immersed in Dulbecco's modified Eagle's medium (DMEM) using mass spectroscopy (ICP-MS). The media were either unchanged or regularly replenished. The pH, surface microstructure and phase changes of aged materials were assessed. Wistar rat femoral bone marrow stromal cells (BMSCs) and cutaneous fibroblasts were isolated, cultured and seeded for cell counting (trypan blue live/dead) after exposure to non-aged, 30- and 180-days-aged samples in regularly replenished DMEM. Aged DMEM in contact with materials was also used to culture BMSCs to investigate the effect of material leachates on the cells. Gene expression analysis was also carried out after direct exposure of cells to non-aged materials. Differences between groups were statistically tested at a significance level of 5%. All materials exhibited alterations after immersion in DMEM and this increased with longer exposure times. The bismuth leached from ProRoot MTA as detected by ICP-MS. Aged ProRoot MTA samples exhibited a black discolouration and surface calcium carbonate deposition. ProRoot MTA influenced cell counts after direct exposure and its 180-days leachates reduced BMSC viability. After direct BMSC contact with non-aged ProRoot MTA an upregulation of metallothionein (MT1 and MT2A) expression and down-regulation of collagen-1a (Col-1a) and bone sialoprotein (BSP) expression was identified. Bismuth leaching was observed throughout 180-days observation period from all materials containing bismuth oxide. This negatively influenced cell viability and gene expression associated with bismuth exposure. This is the first study to report that metallothionein gene expression was influenced by exposure to ProRoot MTA.

Effect of CaCO3, humic acid, and arbuscular mycorrhizal applications on soybean growth in ultisol of Sijunjung, West Sumatra

Soybean is an important source of cheap protein. However, an adequate supply of soybeans is still challenging in Indonesia. This research aimed to evaluate the morphological, physiological, and yield responses of soybeans from the application of calcium carbonate (CaCO3), humic acid, and arbuscular mycorrhizal fungi (AMF). The research was conducted from December 2022 to April 2023 at the ultisol soil of Sijunjung Regency, West Sumatra. The experiment used a split-split-plot design with three replications. The first factor was AMF and without AMF application. The second factor was humic acid and without humic acid. The third factor was doses of CaCO3 application: 0, ¼, ½, ¾, and 1 time of exchangeable Al. The results showed that CaCO3 application significantly affected root length, shoot dry weight, N-tissue content, soil pH, and exchangeable Al. The application of AMF affected the percentage of AMF colonization. The yield components did not show any significant differences among treatments. However, the yield was 24.85% higher than that written in the official description. Therefore, the application of CaCO3 or humic acid or AMF could be a potential solution to increase soybean yields in ultisol. It needs further evaluation in the field to support future farming practices. Keywords: Al-exch; calcium carbonate; N-tissue content; productivity; soil pH

Preparation of high-purity fluorite and nanoscale calcium carbonate from low-grade fluorite

Preparation of high-purity fluorite and nanoscale calcium carbonate from low-grade fluorite

Experimental study on indirect mineral carbonation using five types of slag for production of high-purity calcium carbonate

Experimental study on indirect mineral carbonation using five types of slag for production of high-purity calcium carbonate

The role of sulfate in the hydrothermal replacement of aragonite single crystals by calcite

Aragonite (CaCO3) is a stable calcium carbonate phase under high pressure conditions. However, its formation in (sub)surface environments, where calcite is the stable polymorph, is widespread. Regardless of its origin, aragonite is expected to undergo transformation into calcite under moderate pressures and temperatures. However, this transformation does not always take place, which results in the presence of abundant aragonitic relics in the geological record. Traditionally, this preservation has been explained by the presence of chemical inhibitors that prevent the conversion of aragonite to calcite. While it is widely accepted that magnesium (Mg) plays a key role in the polymorphic selection of CaCO3, the influence of other ions has also been suggested. This work evaluates the effect that different concentrations of sulfate (SO42−) in the fluid has on the progress of the aragonite-to-calcite transformation at 220 °C. Our results show that, upon reaction with deionized water or sulfate-poor solutions ([SO42−]aq < 0.1 mM), aragonite single crystals are extensively replaced by calcite aggregates (crystal size > 15 µm) through an interface coupled dissolution-precipitation reaction. The replacement starts at the aragonite crystal surfaces and advances inwards thanks to the development of an extensive network of fractures. Contrarily, when the solution bears higher concentrations of sulfate ([SO42−]aq > 0.1 mM), only a thin layer of smaller crystals of calcite (< 10 µm) form on the aragonite substrates, without any further transformation taking place. We interpret that these smaller crystals exert too little crystallization pressure and fail to promote the development of a network of fractures. In the absence of this network, the aragonite-calcite transformation cannot take place. The transformation does not occur neither when the experiments are conducted with deionized water and fragments of gypsum or anhydrite together with the aragonite grains. The results of this study shed light on the influence of dissolved sulfate in the kinetics of the fluid-driven transformation of aragonite into calcite. These results are useful to understand the preservation of aragonite in a variety of current geological settings and provide valuable insights for better understanding the diagenesis of sedimentary carbonates.

Comparison of calcium carbonate production by bacterial isolates from recycled aggregates.

The new technology of microbially induced calcium carbonate precipitation (MICP) has been applied in construction materials as a strategy to enhance their properties. In pursuit of solutions that are more localized and tailored to the study's target, this work focused on isolating and selecting bacteria capable of producing CaCO3 for posterior application in concrete aggregates. First, eleven bacterial isolates were obtained from aggregates and identified as genera Bacillus, Lysinibacillus, Exiguobacterium, and Micrococcus. Then, the strains were compared based on the quantity and nature of calcium carbonate they produced using thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy with energy dispersive spectroscopy. Bacillus sp. dominated the cultured isolates and, along with Lysinibacillus sp., exhibited the highest CaCO3 conversion (up to 80%). On the other hand, Exiguobacterium and Micrococcus genera showed the poor ability to MICP (21.3 and 20.3%, respectively). Calcite and vaterite were the dominant carbonate polymorphs, with varying proportions. Concrete aggregates have proven to be a source of microorganisms capable of producing stable calcium carbonates with a high conversion rate. This indicates the feasibility of using microorganisms derived from local sources for application in construction materials as a sustainable way to enhance their characteristics.

Calcium ions and calcium carbonate: key regulators of the enzymatic mineralization for soil dispersivity control

Calcium ions and calcium carbonate: key regulators of the enzymatic mineralization for soil dispersivity control

Aragonite and its composites: preparations, properties and applications.

Aragonite, a metastable crystal form of calcium carbonate, exhibits the highest density and hardness among all species. Diversified forms of aragonite composites can be produced through different preparation processes, forming a relatively complete system in various application fields. Their properties and applications are determined by their multiple levels of structures and shapes. However, research information for aragonite‐related fields is currently lacking integration and clarification. This review provides a comprehensive overview on the preparation methods, properties, and potential applications of three main aragonite‐based materials: aragonite particles, nacre‐inspired mineralized aragonite composites (NMACs), and shell‐derived aragonite nanoparticles (SANPs). The formation mechanisms and versatile applications of these materials are thoroughly surveyed based on their initial precursor, reaction conditions, product forms including filler of aragonite whiskers synthesized by carbonation reaction; functional materials of NMACs fabricated by amorphous calcium carbonate‐organic matter (ACC‐OM) mediated process; biomedical materials of SANPs derived from aragonite cockle shells. Overall, this review aims to provide assistance for customized production of aragonite‐based materials as well as new research directions for both pure aragonites and its composites.

#108 Mineral and bone disorders during chronic kidney disease

Abstract Background and Aims The objectives of our work were to describe mineral and bone disorders in patients with chronic kidney disease (CKD) not yet at the dialysis stage and to assess the compliance of phosphocalcic balance indicators with international KDIGO recommendations Method It was a retrospective study conducted over a 10-month period (01 November 2018 to 31 August 2019) in the nephrology and haemodialysis department of the Renaissance University Hospital in Ndjamena. We have included all patients followed up in the unit for non-dialysis CKD, aged over 18 years and consenting to participate to this study. Results A total of 387 patients files were collected, 82 of which have been taken on. The average age of the patients was 52.7 (± 15.8) years, with a male predominance (67.1%). The comorbidities were arterial hypertension (71.9%) and diabetes (24.4%). CKD has predominated in stage V (55%), followed by stage III (23%). Clinical signs were mainly diffuse bone pain (37.8%), pruritus (8.5%), muscle pain (7.3%) and insomnia (8.5%). Disorders in phosphocalcic metabolism have been noticed in stage IV (11.9% and 10.7%) and stage V (40.5% and 34.5%) for hypocalcaemia and hyperphosphataemia. Secondary hyperparathyroidism and 25 OH vitamin D deficiency were respectively 28.8% and 40.5% in stage V CKD. Compliance with international KDIGO recommendations was 59.7%, 53.7% and 37% respectively for serum calcium, serum phosphorus and parathyroid hormone. Radiological fractures were observed in 4.9% of patients. The management of these disorders has focused on calcium carbonate (52.4%), native vitamin D (64.6%) and Cinacalcet (6.1%) administration. Hypocalcaemia (p = 0.005) and hyperphosphataemia (p = 0.0001) were higher in stage V patients, with a significant difference. Conclusion The treatment of mineral and bone disorders has way to go for the majority of patients, due to lack of resources and the exorbitant cost of treatment. Prevention of mineral and bone disorders is a fundamental pillar of CKD treatment for our patients.

#1018 Profiles of medication use in dialysis patients globally

Abstract Background and Aims Global patterns of medication use in dialysis have not been defined so far. This project aims to provide a real-world view of medication use in dialysis and to characterize therapeutic classes and types of medications. An anonymized dialysis dataset of a global kidney care network called Apollo Dial DB was used. The most common prescribed medications administered at home by the patients were assessed. Method This is a multi-center, retrospective study using real-life data from adult dialysis patients captured in the first version of the Apollo Dial DB dataset. This dataset contains anonymized dialysis data (longitudinal observation level data) on more than 540,000 unique dialysis patients in 40 countries from Jan 2018-Mar 2021. Home medications were analyzed based on Anatomical Therapeutic Chemical (ATC) codes. Top (most common) 5 ATC codes for home medication are presented, once as 4-digit ATC code classes (e.g., A12A for Calcium) and once as full/exact ATC code (e.g., A12AA04 as 7-digit code for Calcium carbonate). Results In Apollo Dial DB 497,723 patients had 10,538,324 documented home medication entries (on average 21 medication prescriptions per patient outside the dialysis clinic), thereof 114,978 patients had 1,607,168 ATC code entries. Each ATC code entry represents a documented prescription of individual length. All percentages shown below are related to 1,607,168 ATC code entries (not to patients). The top 4-digit ATC code classes of home medication were Calcium (8.60%), Vitamin A and D, including combinations (7.33%), All other Therapeutic Products (6.84%), Antithrombotic Agents (5.89%) and Selective Calcium Channel Blockers with mainly vascular Effects (5.39%) (Fig. 1). Out of the ATC class Calcium, Calcium carbonate (4.89%) and Calcium acetate (3.22%) are listed as number 1 and 3 of the top 5 ‘full’ ATC codes. Alfacalcidol (3.36%) of ‘Vitamin A and D, including combinations’ is also number 2 of the ‘full’ ATC code list. Amlodipine (3.07%), number 4 of the full ATC code list, represents the majority of ‘Selective Calcium Channel Blockers with mainly vascular Effects’. Sevelamer of ‘All other Therapeutic Products’ is listed as number 5 in the ATC code list with 2.91% (Fig. 2). Conclusion The top 5 home ATC classes of medications account for 34% of all home prescriptions in dialysis patients. They largely represent phosphate binders, vitamin A &amp; D, antithrombotics, and antihypertensives/antiarrhythmic medications. Although, outside the dialysis clinic each patient has on average 21 medication prescriptions, a lot of these prescriptions represent the major medication classes. It is worthwhile to mention the presented data are related to prescriptions and not to duration of use, e.g., both a medication prescribed for 6 months and a prescription for 1 week are documented only once, even if time on drug varies. Further research is needed to explore global patterns, including further ATC code groups particularly on a patient level, accounting for duration of use and medication formulations, real-world application of various drugs (e.g., GLP1 drugs, HIF PH inhibitor) and accounting for US data with NDC codes.

Preparation, Surface Modification, and Building Materials Applications of Calcium Carbonate Nanoparticles

Preparation, Surface Modification, and Building Materials Applications of Calcium Carbonate Nanoparticles

#1807 Use of teriparatide to prevent severe hypocalcemia after parathyroidectomy in dialysis-dependent patients: a feasibility study

Abstract Background and Aims Hungry bone syndrome is a common postoperative complication after parathyroidectomy (PTx) for severe secondary hyperparathyroidism (SHPT). We aimed to conduct a feasibility study to assess the potential impact of teriparatide on the course of postoperative hypocalcemia after PTx in dialysis-dependent patients. Method We performed a randomized controlled pilot study in 20 dialysis-dependent patients with severe SHPT undergoing total parathyroidectomy with autotransplantation of parathyroid tissue. Patients were randomized to receive either 20 mcg teriparatide (Forsteo) subcutaneously on day 1 after surgery in addition to standard postoperative care (n=11) or standard postoperative care alone (n=9). Severe postoperative hypocalcemia was defined as an ionized serum calcium level of less than 0.8 mmol/l during the first 3 days after surgery. Results Patients in the two groups did not differ in terms of pre- and postoperative laboratory data, including PTH, corrected total calcium, ionized calcium and alkaline phosphatase levels – Table 1. Severe hypocalcemia was observed in 6 patients in the teriparatide group (55%) and in 4 patients (44%) in the control group (p=0.99). The proportion of patients with symptoms of hypocalcemia was higher in patients not receiving teriparatide (67% vs 27%, p=0.17), although these differences did not reach statistical significance. All post-PTx patients received standard supplementation according to local protocol, including calcium carbonate 20 gr/day, active vitamin D 2 mcg/day per os, and intravenous calcium gluconate supplementation on demand for symptoms of hypocalcemia (e.g. numbness, tingling, or cramps). Total elemental calcium requirement after surgery (which may serve as a surrogate for the severity of hungry bone syndrome) was higher in patients receiving standard treatment alone (41 [Q1-Q3: 33; 49] grams per hospitalization vs 33 [Q1-Q3: 25; 40] grams in the teriparatide group, p=0.0375) – Fig. 1. The total length of hospital stay was 4 ± 1 days in teriparatide group and 5 ± 2 in control group, p=0.36. Conclusion In dialysis-dependent patients after PTx, we observed a trend towards an alleviation of postoperative hypocalcemia after single injection of teriparatide in addition to routine care. Further studies with larger sample sizes are needed to confirm these preliminary results.