CaSO4 Research Articles

Migration Prevention of Carbonate Apatite Granules Through Crystal Interlocking Driven by Bassanite-to-Gypsum Transformation on Granule Surface

Granular bone substitutes are commonly used in dental treatments owing to their adaptability to irregular bone defects. However, granule migration during and after implantation poses a significant challenge, impairing bone regeneration. This study addresses this issue by setting carbonate apatite (CAp) granules using crystal interlocking owing to the bassanite (calcium sulfate hemihydrate (CSH))-to-gypsum (calcium sulfate dihydrate (CSD)) transformation on the granule surface. CAp granules were mixed with CSH slurry (water/CSH ratio of 0.4) at varying CSH/CAp ratios of 0.33, 0.43, 0.54, 0.67, and 0.82. At all of these mixing ratios, needle-shaped CSD crystals formed on the CAp granule surface, and the CSD crystals interlocked with each other; consequently, CAp granules were set. As the CSH/CAp ratio increased from 0.33 to 0.82, the CSD crystal length increased from 6.58 to 6.79 μm, while the setting time decreased from 30.3 to 15.5 min. Although the porosity of the set CAp granules decreased with an increase in the CSH/CAp ratio, the set granules maintained intergranular spaces of 77.3 μm at a CSH/CAp ratio of 0.82 conducive to cellular infiltration. After immersion in saline for six days, the set CAp granules at a CSH/CAp ratio of 0.82 maintained their original shape, demonstrating enhanced stability compared to lower CSH/CAp ratios where partial or complete collapse occurred. The porosity and specific surface area increased to 59.9% and 3.66 m2/g, respectively, and the intergranular spaces increased to 176.4 μm. Therefore, mixing the CAp granules with CSH at a ratio of 0.82 may prevent granule migration during and after implantation. Moreover, the CSD component of the granules is likely to resorb more rapidly than the CAp component in vivo, promoting porosity in the set granules and facilitating efficient bone replacement.

Thermodynamic Prediction of Scale Formation in Oil Fields During Water Injection: Application of SPsim Program Through Utilizing Advanced Visual Basic Excel Tool

This study focuses on the design and validation of a computer program named “SPsim”, developed using Visual Basic coding and advanced Excel tools to predict the formation of sulfate mineral deposits during water injection in oil fields. Water injection for secondary oil recovery is an effective economic strategy, but it can be negatively impacted by the formation of sulfate minerals such as calcium sulfate, gypsum, barium sulfate, and strontium sulfate. The results of this study demonstrate that SPsim can accurately predict the formation of these mineral deposits based on the composition of the formation water and injection water under various temperature and pressure conditions. Specifically, the formation of barium sulfate and calcium sulfate is observed under certain conditions, which is a significant concern in oil fields. The study also highlights that calcium sulfate, barium sulfate, and strontium sulfate are among the most challenging mineral deposits in the studied fields, while the formation of gypsum deposits is less significant. The program was compared with results from other software tools, such as ScaleChem 3.2 and StimCad 2, as well as field observations. The findings indicate that SPsim provides a reliable and effective tool for predicting and managing sulfate scaling in water injection operations, making it a valuable resource for both industrial and academic applications.

Ambient Pressure Carbonation Curing of Cold-bonded Fly Ash Lightweight Aggregate Using Coal-fired Flue Gas for Properties Enhancement and CO2 Sequestration

In the current CO2 curing process, pure CO2 gas with a concentration exceeding 99% is primarily used. However, flue gas, which typically contains 10-30% CO2, can also be utilized for carbonization. This study sought to explore the viability of employing flue gas for carbonation and assessed the impact of impurity gases such as SO2. Two typical industrial solid wastes (fly ash and coal gangue) were used to substitute a portion of the cement to prepare light aggregates, which were carbonized under varying concentrations of CO2 and SO2. The porosity and water absorption of the samples decreased after carbonation. A higher degree of carbonation was observed at increasing CO2 concentration. Aggregates carbonated with 15% CO2 improved the CO2 absorption by 48%. The actual CO2 uptake reached up to 58.3% of the theoretical value. The presence of SO2 has been found to impact the uptake of CO2. The CO2 uptake initially declined and then increased as the SO2 concentration increased. The existence of SO2 led to varied increases in the leaching concentrations of the aggregates following the process of carbonation, and some even exceed standard limits. In the presence of both CO2 and SO2, SO2 reacted with the aggregates, resulting in the creation of calcium sulfate. This reaction disrupted the structure of the aggregate, facilitating the diffusion of CO2 into the samples.

Effect of different water reducing agents on mechanical properties and micro-mechanism of modified hemihydrate phosphogypsum cementitious materials

The stockpiling of industrial by-product phosphogypsum causes pollution to the environment, and its effective utilization can be achieved by using cementitious materials from undisturbed hemihydrate phosphogypsum (UHPG) obtained by hemihydrate-wet process. This study investigated the creation of modified hemihydrate phosphogypsum mixture by proportionally blending quicklime with UHPG. Modified hemihydrate phosphogypsum cementitious material (MPGCM) was then prepared using melamine superplasticizer (SM) or naphthalene superplasticizer (FDN). The effects of these water reducing agents on the mechanical properties and micro-mechanisms of MPGCM were evaluated by single-factor experimental method. The results showed that both SM and FDN were effective in reducing water consumption and enhancing the fluidity of MPGCM. Additionally, both superplasticizers delayed the establishment of the MPGCM, with FDN showing a stronger retarding effect than SM. Compared with those mixed with FDN, the specimens mixed with SM exhibited markedly greater flexural and compressive strengths. The specimens with 2 % SM content achieved the highest 28 d flexural strength and compressive strength, measuring 16.61 MPa and 42.26 MPa. Microscopic analysis revealed that the water reducing agent can not only inhibit the disaggregation and dissolution of calcium sulfate hemihydrate and the crystallization of calcium sulfate dihydrate, but also promote the transformation of calcium sulfate dihydrate crystals from long rods to short columns or plates, so that the reticular structure is more compact and the mechanical strength is improved. This study suggests that the optimal composition, consisting of 97 % UHPG, 3 % quicklime, and 2 % SM, yields the optimum mechanical properties. These results provide a theoretical foundation for the application of phosphogypsum in practical engineering and support the sustainable development of phosphorus chemical industries.

The use of antibiotic-loaded calcium sulphate beads in debridement, antibiotics, and implant retention (DAIR) for periprosthetic infections: a retrospective comparative cohort on outcome.

We aimed to compare the effect of calcium sulphate (CS) beads loaded with antibiotics on infection eradication in debridement, antibiotics, and implant retention (DAIR) of periprosthetic joint infection relative to DAIR without local antibiotics delivery. 176 patients with hip or knee arthroplasty undergoing DAIR were retrospectively identified and divided into a bead group (n = 102) and a control group (n = 74). Infections were classified as early postoperative, acute hematogenous, and chronic. Logistic regression analyses were performed on the use of CS beads. Revision-free and infection-free survival was estimated using Kaplan-Meier analysis. Reinfection occurred in 36% of the bead group, and 39% of the control group (odds ratio [OR] 0.9, 95% confidence interval [CI] 0.5- 1.6); reoperation rates were 34% and 43% (OR 0.7, CI 0.4-1.3). Kaplan-Meier analysis showed no statistically significant difference between the 2 groups regarding infection-free (HR 1.1, CI 0.7-1.8) and revision-free (HR 1.1, CI 0.7-1.9) survival rates. In acute hematogenous PJIs, reinfection (29% vs 56%, OR 0.3, CI 0.1-1.1) and reoperation rates (25% vs 61%, OR 0.2, CI 0.1-0.8) were reduced when CS beads were used; Kaplan-Meier analysis revealed higher infection-free (HR 0.5, CI 0.2-1.4) and revision-free (HR 0.5, CI 0.2-1.3) survival rates in the bead group but not of statistical significance. Wound drainage was not increased by CS beads use (OR 1.0, CI 0.99-1.01), but hypercalcemia was seen in 9% in the bead group. DAIR with antibiotic-loaded CS beads did not improve outcome in early postoperative and chronic PJIs, but reduced the reoperation rate in acute haematogenous infections with similar results compared with early postoperative PJIs.

System Dynamics Modeling of Scale Formation in Membrane Distillation Systems for Seawater and RO Brine Treatment

To overcome the limitations of traditional Reverse Osmosis (RO) desalination, Membrane Distillation (MD) has gained attention as an effective solution for improving the treatment of seawater and RO brine. Despite its potential, the formation of inorganic scales, particularly calcium sulfate (CaSO4), continues to pose a major challenge. This research aims to explore the scaling mechanisms in MD systems through a combination of experimental analysis and dynamic modeling. Using real seawater and RO brine as feed sources, the scaling behavior was examined under various operational conditions, such as temperature and feed concentration. Optical Coherence Tomography (OCT) was utilized to monitor the real-time development of fouling layers, offering valuable insights into surface crystal formation processes. A System Dynamics Model (SDM) was created based on the experimental data to predict flux decline trends with precision. The model correlated well with experimental observations, highlighting key factors that drive scaling severity. This integrated approach deepens our understanding of scaling dynamics and provides actionable strategies to mitigate fouling in MD systems, thereby enhancing the efficiency and stability of MD desalination operations. Ultimately, this study underscores the potential of combining OCT with system dynamics modeling as a powerful approach for visualizing and validating scaling processes, offering a practical framework for optimizing MD performance and contributing to more sustainable desalination practices.

A new approach to reducing slagging based on laser modification of heating surfaces: Field tests and mathematical modeling

The article presents the results of field tests of a new approach to reducing slagging of a boiler furnace. The approach involves laser radiation treatment of metal surfaces to obtain a coating with a high degree of passivation and a special texture (microchannel or anisotropic). Due to the texture and formation of the oxide layer, the resistance of the heating surfaces to adhesion of hydrocarbon fuel combustion products, including slag, is increased. Field tests were conducted over 60 days in an operating boiler burning brown coal, the combustion products of which form solid ferrous and sulfate–calcium deposits. The study used scanning microscopy, X-ray fluorescence spectral analysis and mass analysis of slag deposits. The results showed that steel samples with the Microchannels texture formed by laser radiation are characterized by increased resistance to adhesion of brown coal slag. Using the original software code, a mathematical model has been developed to describe the slag deposition process on heat exchange surfaces modified by laser radiation. A numerical simulation was performed under conditions of dynamic change in the thickness of the slag layer on the surface of the heat exchanger pipe to assess the heat transfer characteristics in the “hot flue gases – slag layer – pipe wall – liquid coolant” system. The results showed that the steel surface modified by laser radiation, compared to the untreated surface, is resistant to slagging at the initial stages of interaction with molten ash from different types of fuel. The use of laser-modified surfaces in boiler furnaces will increase the intervals between procedures for cleaning the furnace from slag by up to 64 %. Also, due to the increase in absorbed heat per unit area by 1.6–2.2 times, the use of laser-modified surfaces increases the efficiency of energy production.

Study of the mechanism of manufacture of (alginate) based on the change of chemical and biological properties of polystyrene

Our current research includes the manufacture of alginate material used in the field of dentistry (it is a powder material that is used after converting it into an emulsion and then solid as a mold that works to locate defective teeth in order to repair them, whether they are fixed or mobile). This is done by altering some of the chemical and biological properties of polystyrene, which is an elastic plastic (a synthetic aromatic hydrocarbon polymer derived from a monomer known as styrene). We used polystyrene, zinc oxide, calcium sulfate, gypsum, wax printing compound, and tri-sodium phosphate, there percentage are:(35%, 30% , 17%, 10%, 5%, and 3%) respectively. Alginate can be manufactured as powder, or foam as a flexible paste. Since polystyrene can be transparent in its natural form in many cases, it can be colored in different colors with polar specifications, and it can be used in many industrial and medical fields. Alginate is used in protective packaging for food, industrial and pharmaceutical products. Alginates are among the most commonly used materials in dental clinics, and they are used every day to make molds for dentures.

High Strength Anhydrite Cement Based on Lime Mud From Water Treatment Process: One Step Synthesis in Water Environment, Characterization and Technological Parameters

ABSTRACTIn the process of water treatment from surface water sources, lime mud as waste is formed. This waste contains CaO, Ca(OH)2, and CaCO3. The article proposes a comprehensive method for processing lime mud into high‐strength anhydrite cement. The method involves the interaction of lime mud with waste sulfuric acid from the production of polymer fibers using a structure‐controlled method in the (CaO·Ca(OH)2·CaCO3)—H2SO4—H2O system at a temperature of 40°C. X‐ray diffraction analysis showed the presence of CaSO4 and CaSO4·0.62H2O phases with a purity of 99.8%. The structure‐controlled method makes it possible to control the formation and growth of calcium sulfate crystals of the required shape and size, due to which it is possible to obtain anhydrite cement with desired properties. Combined grinding of synthetic anhydrite with activator additives makes it possible to obtain anhydrite cement with a strength of up to 28.5 MPa.

Effect of ground granulated blast-furnace slag slurries by wet-grinding on the mechanical properties and hydration process of hemihydrate phosphogypsum

Improving the performance and utilization rate of β-hemihydrate phosphogypsum (β-HPG) is an important measure to reduce the environmental pollution of phosphogypsum (PG). In this study, wet grinding was employed to increase the fineness of ground granulated blast-furnace slag (GGBS), thereby facilitating its use in the modification of β-HPG. Two different particle sizes of GGBS slurries were prepared, with D50 values of 6.71 µm and 4.17 µm, respectively. The results indicate that specimens with 20 % wet-ground GGBS (WT2G20) have a remarkable 216.1 % increase in 28 d compressive strength and a 114.7 % increase in the softening coefficient compared to specimens without GGBS, and the hydration heat flow is delayed, but the total exothermic quantity increased from 67.8 J/g to 75.6 J/g, simultaneously. Ettringite, gels and other hydration products increase with the increase of GGBS slurry fineness. These products are filled between the pores of calcium sulfate dihydrate (DH) crystal or lapped together to protect the crystallization point of DH crystal, which will not cause volume stability problems, further reducing the overall porosity of the system, and making the microstructure of the hardened paste more compact. Accordingly, GGBS after wet-grinding can markedly enhance the macro properties of β-HPG, developing a cementitious material that is effective and environmentally friendly for utilizing PG.

From Ions to Crystals: A Comprehensive View of the Non-Classical Nucleation of Calcium Sulfate.

The early stages of mineralization continue to be in the focus of intensive research due to their inherent importance for natural and engineered environments. While numerous observations have been reported for single steps in the pathways of various crystallizing phases in previous studies, the complexity of the underlying processes and their elusive character have left central questions unanswered in most cases. In the present work, we provide a detailed view on the nucleation of calcium sulfate mineralization-an abundant mineral with broad use in construction industry-in aqueous systems at ambient conditions. As experimental basis, a co-titration procedure with potentiometric, turbidimetric and conductometric detection was developed, allowing solution speciation and the formation of crystallization precursors to be monitored quantitatively as the level of nominal (super)saturation gradually increases. The nature and spatiotemporal evolution of these precursors was further elucidated by time-resolved small-angle X-ray scattering (SAXS) and analytical ultracentrifugation (AUC) experiments, complemented by cryogenic transmission electron microscopy (cryo-TEM) as a direct imaging technique. The results reveal how ions associate into nanometric primary species, which subsequently aggregate and develop anisotropic order by intrinsic structural reorganization. Our observations challenge the common understanding of fundamental notions such as the nucleation barrier or the meaning of supersaturation, with broad implications for mineralization phenomena in general and the formation of calcium sulfate in geochemical settings and industrial applications in particular.

Von Ionen zu Kristallen: Neue Einblicke die nicht‐klassische Keimbildung von Calciumsulfat

AbstractDie frühen Stadien der Mineralisierung stehen aufgrund ihrer inhärenten Bedeutung für Prozesse in natürlicher Umgebung sowie in technischen Anwendungen weiterhin im Fokus intensiver Forschung. Obwohl bereits viele wertvolle Beobachtungen für einzelne Schritte in den verschiedenen Phasen eines Kristallisationsvorgangs berichtet wurden, blieben wesentliche Fragen zumeist unbeantwortet aufgrund der Komplexität der zugrundeliegenden Mechanismen und des transienten Charakters der beteiligten Vor‐ und Zwischenstufen. In der vorliegenden Arbeit geben wir einen detaillierten Überblick zur Keimbildung von Calciumsulfat (einem Mineral mit großer Bedeutung für die Bauindustrie) in wässrigen Systemen bei Umgebungsbedingungen. Als experimentelle Grundlage wurde ein Titrationsverfahren mit gleichzeitiger potentiometrischer, turbidimetrischer und konduktometrischer Detektion entwickelt, um die Assoziation von Ionen in Lösung und die Bildung von Vorläuferstrukturen bei kontinuierlich ansteigender nomineller Übersättigung quantitativ verfolgen zu können. Die Eigenschaften dieser Präkursoren und ihre zeitliche Entwicklung vor und während der Nukleation wurden in situ mittels Kleinwinkel‐Röntgenstreuung (SAXS) und analytischer Ultrazentrifugation (AUC) aufgeklärt. Zusätzlich wurde Transmissionselektronenmikroskopie unter kryogenen Bedingungen (Kryo‐TEM) als bildgebendes Verfahren genutzt. Die Ergebnisse zeigen, wie sich Ionen zu nanometrischen Primärspezies verbinden, die anschließend aggregieren und durch intrinsische strukturelle Reorganisation eine anisotrope Ordnung entwickeln. Unsere Beobachtungen stellen das gängige Bild von grundlegenden Begriffen wie der Keimbildungsbarriere oder der Bedeutung der Übersättigung in Frage. Daraus ergeben sich weitreichende Auswirkungen auf unser Verständnis von Kristallisationsphänomenen im Allgemeinen und der Bildung von Calciumsulfat in geochemischen und angewandten Systemen im Besonderen.

Calcium sulfate-based load-bearing bone grafts with patient-specific geometry

The treatment of bone defects with complex three-dimensional geometry presents challenges in terms of bone grafting and restoration. In this paper, we propose a rapid and effective method that uses 3D printing, ceramic casting, and the incorporation of mesh reinforcement to create load-bearing bone grafts with patient-specific three-dimensional geometry. Using two types of facial bones as examples, we show that this fabrication method has a high degree of geometrical fidelity. We also experimentally study the fracture behavior of six different architectures designed for the treatment of mandibular defects, one of the principal load-bearing facial bones. These design configurations include un-reinforced calcium sulfate samples, and samples reinforced with one or two layers of stainless steel, poly (lactic acid), and poly (L-lactic acid). The results suggested a trade-off between energy dissipation and maximum load based on the position of the metal mesh in the sample. Samples reinforced with one layer of metallic mesh at their lowermost margin exhibited a 17% higher stiffness and a 21.3% higher peak load, while samples with a layer of metal mesh embedded within dissipated 16% more energy. Samples with two layers of metallic mesh demonstrated the highest improvements among all samples, dissipating 5767.85% more energy and exhibiting a peak load 145.6% higher compared to plain CS. The improvements in stiffness for SD, SL, and S2 were 3%, 21.3%, and 21.9% respectively compared to the plain ceramic. In contrast, PLA mesh improved energy dissipation by 96.71% but reduced the peak load by 29.18%, while PLLA mesh decreased both the peak load and the dissipated energy by 13.05% and 35.31%, respectively. While PLA mesh reduced stiffness by 11% compared to plain CS, PLLA mesh-reinforced samples were slightly stiffer than pure CS by 1.6%.

The Effectivity of Acemannan Sponge and Calcium Phosphate Cement-Calcium Sulfate Hemihydrate (CPC-CSH)-Diode Laser-Assisted Method on the Direct Pulp Capping

Dental caries, the decay of tooth, affects approximately 2.3 billion people worldwide and reaches 88.8% of the total Indonesians. Caries reaching the pulp requires direct pulp capping (DPC) therapy to preserve pulp vitality. Ca(OH)2 is the golden standard DPC material, but its adhesion and mechanical properties are poor. Therefore, an alternative therapy is needed to improve the success of DPC using acemannan sponge and calcium phosphate cement-calcium sulfate hemihydrate (CPC-CSH)-diode laser. Acemannan, polymannose extracted from aloe vera gel, plays a role in reparative dentin formation that is immunomodulatory, antimicrobial, biocompatible, and accelerates wound healing. Calcium Phosphate Cement (CPC), bioactive material used in tissue engineering. Calcium sulfate hemihydrate (CSH), inorganic component and biocompatible. The combination of CPC-CSH can shorten the setting time, maintain compressive strength, and has good handling properties. Low level diode laser (LLDL) plays a role in reparative dentin formation by altering growth factors expression to stimulate cell proliferation and fibroblast development. LLDL is applied before pulp capping material application between the pulp-dentin so that aggregated collagen fibrils are collected and stimulate the formation of odontoblasts. This paper aims to describe The Effectiveness of Acemannan Sponge and Calcium Phosphate Cement-Calcium Sulfate Hemihydrate (CPC-CSH)-Diode Laser Assisted Method in Direct Pulp Capping Therapy. Article searching uses the Preferred Reporting Items for Systematic Reviews and Meta-analyses with keywords (MeSH): "DPC and Acemannan", "DPC and CPC-CSH", and "DPC and Diode Laser" from Pubmed, ScienceDirect, and Google Scholar databases in 2019-2024. Acemannan Sponge and Calcium Phosphate Cement-Calcium Sulfate Hemihydrate (CPC-CSH)-Diode Laser Assisted Method are effective as Alternative Direct Pulp Capping Therapy.

Unlocking the Value of Phosphogypsum Waste: Steam Calcination for Efficient Decomposition and Resource Recovery

ABSTRACT Phosphogypsum is a waste by-product of phosphate fertilizer production. It contains calcium sulfate (CaSO4.xH2O), which can be decomposed to produce calcium oxide (CaO) and sulfur dioxide (SO2). Steam calcination is a process that uses steam to decompose CaSO4. This study represents the first comprehensive investigation of steam calcination applied to phosphogypsum, comparing its performance to pure CaSO4 at various temperatures (1050–1200 °C) and steam molar ratios (0, 4%, and 30%). The results showed that steam calcination can significantly lower the calcination temperature of both CaSO4 and phosphogypsum. The presence of steam can significantly accelerate the decomposition reaction of pure CaSO4 and phosphogypsum when compared to decomposition in nitrogen or air. It was found that the decomposition reaction in steam follows the contracting cylinder reaction model in the case of CaSO4 and the first-order reaction model for the phosphogypsum. Additionally, the activation energy for the steam calcination of CaSO4 and phosphogypsum were found to be 421.2 kJ/mol and 418.6 kJ/mol, respectively, which are lower than the activation energy for the calcination in oxyfuel combustion products (O2, CO2, SO2, and H2O gases) 531.4 kJ/mol demonstrating its potential for enhanced energy efficiency. As a result, steam calcination emerges as a promising sustainable solution for valorizing phosphogypsum while reducing energy consumption and greenhouse gas emissions.

Utilisation of By-Product Phosphogypsum Through Extrusion-Based 3D Printing.

Phosphogypsum (PG) is a phosphate fertiliser by-product. This by-product has a low level of utilisation. Calcium sulphate is dominated in PG similar to gypsum and, therefore, has good binding properties (similar to natural gypsum). However, the presence of water-soluble phosphates and fluorides, an unwanted acidic impurity in PG, makes PG unsuitable for the manufacture of gypsum-based products. In this study, the binding material of PG (β-CaSO4·0.5H2O) was produced from β-CaSO4·2H2O by calcination. To neutralise the acidic PG impurities, 0.5 wt% quicklime was added to the PG. In the construction sector, 3D-printing technology is developing rapidly as this technology has many advantages. The current study is focused on creating a 3D-printable PG mixture. The 3D-printing paste was made using sand as the fine aggregate and a binder based on PG. The results obtained show that, despite the low degree of densification, 3D printing improves the mechanical properties of this material compared to cast samples. The 3D-printed specimens tested in [u] direction reached the highest compressive strength of 950 kPa. The cast specimens showed a 17% lower compressive strength of 810 kPa. The 3D-printed specimens tested in the [v] and [w] directions reached a compressive strength of 550 kPa and 710 kPa, respectively.

From Structure to Strength: Analyzing the Impact of Sulfuric Acid on Pig Bone Demineralization Through FTIR, LIBS, and AAS.

The present research aimed to investigate the demineralizing effects of sulfuric acid on pig bone. Alterations in collagen and phosphate contents and changes in the elemental composition of the bone during the 14-day-long immersion in sulfuric acid solutions of different concentrations were estimated using ATR-FTIR, LIBS, and AAS. FTIR spectra at amide I (1800-1600 cm-1) and phosphate ν1/ν3 (PO43-) (1300-900 cm-1) domains were scrutinized using the deconvolution method for monitoring changes in the protein secondary structure and mineral content. The results implicated sulfuric acid as a powerful demineralization agent and effective in targeting mineral components, such as hydroxyapatite, while leaving the collagen matrix relatively preserved with a complex secondary structure. Collagen maturity marker values gave valuable insights into the structural integrity of the bone. LIBS and AAS indicated changes in bone hardness; phosphorous-to-carbon ratio; and calcium, phosphorous, and magnesium content in the solutions left after the immersion period. The changes in the ratio of ionic-to-atomic calcium lines in the LIBS spectra indicated hardening of the bone, with increasing acid concentration and prolonged action, due to the deposition of calcium sulfate on the surface. The calcium concentration in the solutions decreased with increased acid concentration, while the change in phosphorus and magnesium concentrations was reversed.

3D-Printed Bioceramic Scaffolds Reinforced by the In Situ Oriented Growth of Grains for Supercritical Bone Defect Reconstruction.

Porous calcium phosphate ceramics have attracted widespread attention owing to their excellent bioactivity. However, their poor mechanical properties severely limit their clinical applications. Significantly improving the mechanical strength of porous CaP ceramics while maintaining their bioactivity remains a major challenge. To address this issue, calcium sulfate is used to regulate the directional growth of hydroxyapatite grains during ceramic sintering. The in situ oriented grains can not only alleviate the stress concentration but also strengthen the bonding force between the ceramic grain boundaries. Calcium sulfate improves the release of active calcium ions from calcium phosphate ceramics, further enhancing their bioactivity and osteoinductivity in vivo. Transcriptome and proteome sequencing reveals that the in situ whisker-reinforced ceramics increase the expression of proteins related to calcium ion binding and promote the expression of osteogenesis-related proteins. In the supercritical bone defect repair model, repair of the defect is achieved within 3 months, with mechanical recovery reaching more than 70% of the autologous bone.

Coating development on mine waste rocks as a protective sink to attenuate the off-site migration of antimony in the environment

This study explored the feasibility of depositing protective coatings with an Sb scavenger function on mine waste rocks derived from the exploitation of stibnite deposits. Encapsulation treatments were performed using ferrous sulfate as the coating precursor. Different Fe/Sbleachable molar ratios (0.1, 1, and 10) were evaluated using hydrothermal and thermal processes at various temperatures (30, 50, 100, and 150 °C). The environmental characterization of the coated mine waste was established using standard leaching tests. The most effective coatings were analyzed for their mineralogy, chemical composition, and Sb attenuation using X-ray powder diffraction, scanning electron microscopy, and digestion/extraction processes. Additionally, stability tests were conducted to assess the effectiveness of encapsulation under changing environmental conditions. The Fe/Sbleachable molar ratio was found to be a critical factor in reverting the toxic and hazardous characteristics of mine wastes, with an optimal value of 10. The coatings were primarily composed of Fe oxyhydroxy sulfates/Fe oxyhydroxides and calcium sulfate minerals with a bulk Sb content of approximately 1 %. The adsorbed Sb content in the coatings was a small fraction of the total Sb content (< 0.5 %), indicating a strong retention. Moreover, such coatings were stable under different pH (3−8) and redox (100 to −100 mV) conditions.

The Efficacy of Calcium Sulfate/Hydroxyapatite (CaS/HA) Gentamicin in Osteomyelitis Treatment: A Case Series.

Osteomyelitis is a challenging condition caused by infection and inflammation of the bone, presenting a significant economic burden to healthcare systems. Calcium sulfate/hydroxyapatite (CaS/HA) is a bone void filler composed of 60% calcium sulfate and 40% hydroxyapatite. This case series aimed to report the efficacy and infection-related outcomes of CaS/HA combined with Gentamicin (CaS/HA-G) in treating osteomyelitis. Patients aged 18 and older diagnosed with osteomyelitis requiring surgical intervention and treated with CaS/HA-G during their procedure were included in the study, with a median (Q1-Q3) = 10 (7-16)-month follow-up period of time. Data collected included demographic, surgical, and outcome information. Infection eradication was determined by the normalization of the C-reactive protein, erythrocyte sedimentation rate levels, or the absence of clinical infection symptoms. The case series involved 21 patients (twelve male, nine female) with a mean (SD) age of 54.8 (16.6) years. Vancomycin or/and Tobramycin were used as an additional antibiotic in 17 patients. At the last follow-up, 20 out of 21 patients (95.2%) had eradicated the infection, with a median (Q1-Q3) eradication time of 128 (71.8-233.5) days. In conclusion, this study demonstrates that CaS/HA-G is effective in controlling osseous infection in osteomyelitis while acting as an absorbable bone void filler.