Bassanite Research Articles

A novel expandable porous composite based on acetalized polyvinyl alcohol and calcium sulfate used for injectable bone repair materials

Calcium sulfate hemihydrate (CaSO4·1/2H2O; CSH) has been used for filling bone defects because of its excellent biocompatibility and injectability. Researchers have devoted in improving its performance to adapt to various demands. However, up to now, no studies have reported bone cement with expandable ability. In this study, a novel expandable bone cement was prepared with acetalized polyvinyl alchol porous material (APVA-PM) and CSH. By controlling the content of APAV-PM, composite cements with different structures and morphology were obtained and investigated by using SEM, FT-IR, XRD. The physical properties including setting time, porosity and expansion ratio were studied. CSH/APVA-PM bone cement could produce volume expansion in the setting process and form a porous structure after curing. The setting time decreased with the increase of the volume fraction of APVA-PM. APVA-PM improved the toughness of calcium sulfate cement, thus overcoming the present mechanical limitations. In vitro experiments demonstrated the CSH/APVA-PM bone cement did not show cytotoxicity and the porous structure allowed the rat bone marrow stem cells (BMSCs) to grow into the pores. Therefore, CSH/APVA-PM bone cement appeared to be useful for bone tissue engineering and can potentially serve as a new filling material.

Effects of superplasticisers on hydration process, structure and properties of α-hemihydrate calcium sulfate

Polycarboxylic superplasticiser (PS) and naphthalene-based superplasticiser (NBS) were used to achieve a denser structure of α-hemihydrate calcium sulfate and better mechanical properties. The hydration process was investigated by thermogravimetric analysis (TGA), which showed that the PS decelerated the whole hydration process of α-hemihydrate calcium sulfate, whereas the NBS accelerated the process in the early stage and decelerated it in the late stage. It was noteworthy that they both could increase the highest hydration heat. The PS delayed the hydration heat peak whereas the NBS advanced it. Both scanning electron microscopy and pore property analysis confirmed the formation of a more compact structure of the hydration product. Optimal mechanical properties of α-hemihydrate calcium sulfate were obtained with 0·5% NBS or 0·4% PS by mass. Under the same conditions, the PS was more efficient at improving the properties of α-hemihydrate calcium sulfate than the NBS.

Comparison of the effect of hemihydrate calcium sulfate granules and Cerabone on dental socket preservation: An animal experiment.

Background. Early bone loss due to tooth extraction can be significantly reduced by socket preservation. The aim of this study was to compare the in vivo effects of hemihydrate calcium sulfate granules (an alloplastic material) and Cerabone (a bovine-derived xenograft) on socket preservation in dogs. Methods. Six male Mongrel dogs were randomly divided into 2 groups (n=3) for sacrificing and histological evaluation 4 and 8 weeks after a surgery. The second and third premolars on both sides of the lower jaw were extracted surgically. The sockets on one side were filled with Cerabone, and with calcium sulfate on the opposite side. In the slides, the ratio of the area of newly formed bone to the area of the entire cavity, and the ratio of the area of fibrous connective tissue to the area of the entire cavity were measured. The presence of inflammation was also examined. Wilcoxon signed-rank test, Sign test and McNemar test were used for statistical analyses (ɑ=0.05). Results. The means of new bone proportion were 11% and 8% for Cerabone and calcium sulfate, respectively (P=0.58). The means of connective tissue proportion were 29% and 33% for Cerabone and calcium sulfate, respectively (P=0.72). No inflammatory cells were observed in the Cerabone group, although 50% of the samples in the calcium sulfate group showed inflammation (P=0.50). Conclusion. The effects of calcium sulfate and Cerabone on socket preservation in dogs on bone formation, fibrous connective tissue and inflammation levels were not significantly different at 4- and 8-week postoperative intervals.

Effect of additives on hydration and hardening of magnesia compositions

The article is devoted to the investigation of the influence of technological factors on the hydration and hardening of magnesia compositions. The objective – is investigation magnesia compositions with different additives. Factors which impact activity of magnesium oxide in compositions of different structure are investigated. Influence of liquid density on hardening of magnesium bindings is defined. Processes of hydration and hardening of magnesium bindings with participation of minerals – silicates are investigated. It is revealed that the addition of semi-aquatic calcium sulfate contributes to the hardening of magnesia binders. Defined effect of concentration calcium sulfate hemihydrate to the hardening of caustic magnesite. Here are proposed structures of sulphomagnesium compositions containing technogenic components. It revealed a beneficial effect on the hardening of ferrous component of the mixed magnesia binder. Composition of hydration products of magnesium binding with participation of ferriferous minerals is presented. Transformations of phases at hydration of magnesium binding are revealed. Influence of structure of bindings on transformations of hydrates is established. Results of research of magnesia bindings of long hardening are given. It is shown that the durability of stone of bindings is provided with dense structure of hydrates. In researches are used X – Ray and thermal methods, electronic microscopy.

Retardation behavior of hydration of calcium sulfate hemihydrate (bassanite) induced by sodium trimetaphosphate (STMP)

Direct confirmation of the bassanite nanorod intermediate during the hydration of bulk bassanite in the presence of STMP.

Geometric and mechanical evaluation of 3D-printing materials for skull base anatomical education and endoscopic surgery simulation - A first step to create reliable customized simulators.

IntroductionEndoscopic skull base surgery allows minimal invasive therapy through the nostrils to treat infectious or tumorous diseases. Surgical and anatomical education in this field is limited by the lack of validated training models in terms of geometric and mechanical accuracy. We choose to evaluate several consumer-grade materials to create a patient-specific 3D-printed skull base model for anatomical learning and surgical training.MethodsFour 3D-printed consumer-grade materials were compared to human cadaver bone: calcium sulfate hemihydrate (named Multicolor), polyamide, resin and polycarbonate. We compared the geometric accuracy, forces required to break thin walls of materials and forces required during drilling.ResultsAll materials had an acceptable global geometric accuracy (from 0.083mm to 0.203mm of global error). Local accuracy was better in polycarbonate (0.09mm) and polyamide (0.15mm) than in Multicolor (0.90mm) and resin (0.86mm). Resin and polyamide thin walls were not broken at 200N. Forces needed to break Multicolor thin walls were 1.6–3.5 times higher than in bone. For polycarbonate, forces applied were 1.6–2.5 times higher. Polycarbonate had a mode of fracture similar to the cadaver bone. Forces applied on materials during drilling followed a normal distribution except for the polyamide which was melted. Energy spent during drilling was respectively 1.6 and 2.6 times higher on bone than on PC and Multicolor.ConclusionPolycarbonate is a good substitute of human cadaver bone for skull base surgery simulation. Thanks to short lead times and reasonable production costs, patient-specific 3D printed models can be used in clinical practice for pre-operative training, improving patient safety.

Elaboration and Characterization Of Eco-Materials Made From Recycled Or Bio-Based Raw Materials

This work test the feasibility and characterize the thermohygric properties of composite materials, realized with eco-friendly raw materials and designed to make suspended ceilings or interior partition walls. Several raw materials are considered: recycled paper (granules or cellulose wadding) and wood fibers. Aggregates or fibers are bonded with organic or mineral binder. One of the binder considered is starch, due to its availability in Ivory Coast (cassava flour). The calcium sulfate hemihydrate is also used for comparison.The density of the produced composites ranges from 400 to 1200 kg/m3 depending on formulation. The thermal conductivity increases proportionally with the density and ranges from 0.09 to 0.5 W/(m.K). The characterization of hygric behavior is based on the measurement of moisture buffer value (MBV) [1]. The hydric performances of the composites made of mineral binder goes from moderate (MBV around 1 g/(m².%RH)) to excellent (MBV > 2 g/(m².%RH)). The moisture buffer value of the paper granules -starch composite is also excellent (MBV > 2 g/(m².%RH))

In vitro chemosensitivity of feline injection site-associated sarcoma cell lines to carboplatin.

To determine the in vitro chemosensitivity of feline injection site-associated sarcoma (FISAS) cells to carboplatin concentrations generated by elution of carboplatin-impregnated calcium sulfate hemihydrate (CI-CSH) beads. In vitro study. Five immortalized cell lines from histologically confirmed, primary FISASs. For each cell line, one 96-well microplate was used for each time point (24, 48, 72 hours). In each microplate, 3 wells were seeded with ∼7.5 × 103 cells per well for every carboplatin treatment added, ranging from 5 to 450 µM. Microculture plates were incubated for 24, 48, or 72 hours. Drug efficacy was assessed via a bioreductive fluorometric assay. For apoptosis analysis, 3 wells were seeded with ∼5 × 104 cells per well for every carboplatin treatment added, ranging from 5 to 450 µM. Flow cytometry was performed and the relative percentages of viable, apoptotic, and late apoptotic/necrotic cells were reported. All experiments were run in triplicates. Carboplatin exerted dose-dependent and time-dependent effects on FISAS cell viability. The IC50 values were within the range of carboplatin concentrations eluted from CI-CSH beads. Elution of carboplatin from CI-CSH beads generate concentrations sufficient to result in 50% growth inhibition of FISAS cells in vitro. Local tumor control might be achieved by implantation of CI-CSH beads immediately following radical or marginal excision of the primary tumor or by implantation without tumor resection.

Morphological regulation of calcium sulfate hemihydrate from phosphogypsum

AbstractThe calcium sulfate hemihydrate whiskers were prepared from phosphogypsum at hydrothermal condition. The influences of different organic acid (citric acid and poly (acrylic acid)) on the crystal morphology were detected, respectively. The morphology of crystals can be influenced by adding organic acid. Short and large columnar crystals can be obtained by adding 5 wt.% citric acid, which can be used as cementitious materials. The long columnar crystals with uniform diameter can be obtained by adding poly (acrylic acid), which can be applied in composites.

Fabrication of octacalcium phosphate foam through phase conversion and its histological evaluation

Octacalcium phosphate (OCP) foam with an interconnected porous structure was fabricated through phase conversion via a dissolution–precipitation reaction using calcium sulfate hemihydrate (CSH: CaSO4·1/2H2O) granules as precursors in a sodium dihydrogen phosphate (NaDP: NaH2PO4) solution. The diametral tensile strength and porosity of the OCP foam were 0.15 ± 0.04 MPa and 69.4% ± 0.04%, respectively. When the OCP foam was implanted into bone defects in a rabbit femur, the OCP foam showed an excellent tissue response, and the bone penetrated into the porous structure. The osteoconductivity and bone-replacement rate were significantly higher than those of an OCP compact.

Effects of metal ions on the morphology of calcium sulfate hemihydrate whiskers by hydrothermal method

The effects of Na+, Mg2+, Al3+ and Fe3+ ion concentrations on the crystal morphology of calcium sulfate hemihydrate whiskers formed via a hydrothermal method have been studied. In the presence of Al3+ concentrations higher than 1×10–3 mol/L the whiskers were significantly shorter and thicker and the presence of Mg2+ and Fe3+ resulted in shorter whiskers. The presence of Na+ did not affect the morphology of the whiskers. Through elemental analysis, it was determined that Mg2+ and Al3+ were selectively adsorbed on the surfaces of the crystals, whereas Fe3+ underwent a hydrolysis reaction to form a brown precipitate which decreased the ion concentration in the solution. These results indicate that in raw materials used for the industrial preparation of calcium sulfate whiskers, Al3+ and Fe3+ should be removed and the Mg2+ concentration should be less than 8 × 10–3 mol/L in order to obtain pure whiskers with high aspect ratios.

Morphology control of calcium sulfate hemihydrates and application in size screening iron/sulfur of jarosite sediment

To separate iron and sulfur in jarosite sediment by using the sieving method, firstly, the jarosite sediment is decomposed by adding calcium oxide to obtain iron hydroxide and calcium sulfate dihydrate mixed precipitation. Secondly, the calcium sulfate hemihydrate (HH) whiskers with a large diameter and iron (hydr)oxides with a small diameter are obtained by treating the mixed precipitation at 140 °C in a hydrothermal condition. Finally, the whiskers and iron (hydr)oxides can be separated by using the sieving method. The whiskers can be used as the reinforcing phase of composites and the (hydr)oxides can be used as raw materials of iron.The influence of the cultivating time, and the maleic acid and solid/solution ratio on the HH crystals morphology was detected in a 140 °C hydrothermal condition. The crystal diameter increased with cultivating time in the 1:20 ratio of solid/solution solution. The aspect ratio of the crystals increased and the diameter decreased, while the addition amount of maleic acid increased in the 1:20 ratio of solid/solution solution for a cultivating time of 6 h. The diameter of the crystal was not significantly changed, but the length became shorter while the ratio of solid/solution increased.The grain size of the iron (hydr)oxides did not significantly change in the hydrothermal condition, which was favorable for separation of iron (hydr)oxides and HH crystals with the sieving method. It was reasonable (economical) to treat the mixed precipitation in the 1:2.5 ratio of solid/solution solution at 140°Cfor 2 h.

Calcium Sulfate Hemihydrate Nanowires: One Robust Material in Separation of Water from Water-in-Oil Emulsion.

Here we report a facile and cost-effective wet-chemical approach to the synthesis of calcium sulfate hemihydrate nanowires (HH NWs, CaSO4·0.5H2O), and their robust performance in immobilizing water molecules to the crystal lattice of CaSO4 and then separating them from a surfactant-stabilized water-in-oil emulsion (mean droplet size of around 1.2 μm). Every gram of HH NWs are capable of treating 20 mL emulsion (water content: 10.00 mg mL-1) with a separation efficiency of 99.23% at room temperature, and this efficiency can be further improved by tuning the surface charge density of HH. Along with the water immobilization, HH NWs are converted to large cubic-like calcium sulfate dihydrate microparticles (DH, CaSO4·2H2O, mean size: 50 μm), and the accompanied size increment enables efficient collection of the solid phase from oil. DH microparticles can be regenerated into HH NWs, which retain the high performance of the original NWs. Such a unique renewable feature improves the economics of our method and simultaneously prevents the secondary pollution. Further economic evaluation finds that purification of every cubic meters of emulsion (water content: 10.00 mg mL-1) will cost about $34.18 for HH NWs, much lower than the $490.78 for the previously reported HH NPs, and $11 052.05-$23 420.32 Fe3O4 NP-based adsorbents, respectively. With the high efficiency, easy collection, low cost, and renewable feature, HH NWs show highly promising applications in the field of oil purification and recycle.

Calcium Sulfate Hemihydrate Whiskers Obtained from Flue Gas Desulfurization Gypsum and Used for the Adsorption Removal of Lead

Abstract: As a recycled material, flue gas desulfurization gypsum has been used to prepare calcium sulfate hemihydrate whisker (CSHW) through hydrothermal synthesis for several decades. However, the subsequent utilization of this resultant material has not yet received considerable attention. In the present research, CSHW was successfully synthesized at a certain region, and was used for the adsorption of lead ions from aqueous solutions, thereby broadening the research field for the practical application of CSHW. Its adsorption capacity was significantly influenced by various parameters, particularly, the pH level and initial lead concentration. The pH value highly affected the hydrolysis degree of lead ions and dominated the adsorption of lead. The equilibrium isotherms under two different temperatures were simulated using Langmuir, Freundlich, and Temkin models. Both Langmuir and Temkin models showed a good fit to the data. Combined with the well-fitted pseudo-second-order model, the adsorption mechanism was thought to be a chemisorption process that was enforced by the ion exchange reaction. In addition, the specific crystal structure of CSHW revealed that ion exchange reaction occurred on the (010) and (100) facets due to their preferential growth and negatively charged property. The residual solid phase after adsorption was collected and detected using X-ray diffraction and scanning electron microscopy with energy dispersive X-ray spectroscopy. Results revealed that PbSO4 was formed on the surface of CSHW. The alkaline condition introduced the tribasic lead sulfate, and thus reduced the stability of the adsorption system.

A novel resource utilization of the calcium-based semi-dry flue gas desulfurization ash: As a reductant to remove chromium and vanadium from vanadium industrial wastewater

A novel resource utilization of the calcium-based semi-dry flue gas desulfurization ash is investigated. In the present study, the semi-dry desulfurization ash is used as a reductant for chromium and vanadium removal by chemical reduction precipitation, the byproduct gypsum and chromium-contained sludge are obtained. Besides, the effects of main operational parameters (reaction pH, desulfurization ash dosage and reaction time) on the heavy metal removal are investigated, and the main reaction mechanism for this treatment technology is also proposed. Under the optimal conditions, the residual concentrations of Cr(VI), total Cr and V are 0.163mg/L, 0.395mg/L and 0.155mg/L, respectively. Additionally, byproduct gypsum and chromium-contained sludge are characterized using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), scanning electron microscope-energy dispersive spectrometer (SEM-EDS) and thermogravimetry differential scanning calorimetry (TG-DSC), respectively. Finally, the resource utilization methods of the byproduct gypsum and chromium-contained sludge from this technology are also submitted. The byproduct gypsum can be utilized to produce hemihydrate calcium sulfate whisker, and the roasted heavy metal precipitation can be used as a primary chromium raw material (Cr2O3 content is about 83%).

Impact of glutamic acid on the transformation of calcium sulfate hemihydrate to dihydrate: Characterization, equilibrium, kinetics, and thermodynamics

ABSTRACTIn this study, the characteristics and mechanisms of glutamic acid adsorption on the transformation process of calcium sulfate hemihydrate to calcium sulfate dihydrate were investigated in a batch-type crystallizer. The phase transformation was followed by conductivity measurements in both the absence and the presence of glutamic acid used as additive. The structure of the samples obtained during this process was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller, thermogravimetric analyzer-mass spectrometer, and ATR-FTIR analyses. From the results, it was shown that the uptake of glutamic acid caused a retarding effect in the transformation rate. It was also found that the thin- and weak-layered structure was replaced by a thick and compact plate-like structure. The adsorption isotherms, kinetics, and thermodynamics were also explored to describe the process. According to the results, the Langmuir isotherm model fit quite well, as demonstrated by the high R2 value, calculated using a linear and nonlinear procedure, and the maximum adsorption amount of 169.49 mg/g. The pseudo-first-order and pseudo-second-order kinetic models were applied to analyze the kinetic experimental data, and it was determined that the adsorption of glutamic acid followed the pseudo-second-order model, which indicates that the adsorption rate depended on chemisorption. The thermodynamic results illustrated that the adsorption of glutamic acid in the transformation process was spontaneous and endothermic.

A facile method of transforming FGD gypsum to \u03b1-CaSO4\xb70.5H2O whiskers with cetyltrimethylammonium bromide (CTAB) and KCl in glycerol-water solution

A facile method to transform flue gas desulfurization gypsum (FGD gypsum) to α- calcium sulfate hemihydrate (α-HH) whiskers with high aspect ratios mediated by cetyltrimethylammonium bromide (CTAB) and KCl in glycerol-water solutions was studied. Addition of KCl facilitated the dissolution of calcium sulfate dihydrate (DH) and created a much higher supersaturation, which could come into being a larger driving force for the phase transformation from DH to α-HH. CTAB as the crystal modifier can significantly promoted 1-D growth of α-HH whiskers along the c axis and the presence of 0.25% CTAB (by weight of FGD gypsum) resulted in the increase of the average aspect ratio of α-HH whiskers from 28.9 to 188.4, which might be attributed to the preferential adsorption of C16H33(CH3)3N+ on the negative side facets of α-HH crystal.

Effect of injectable alpha calcium sulfate hemihydrate for repair of Hill-Sachs lesion in a rabbit model

Effect of injectable alpha calcium sulfate hemihydrate for repair of Hill-Sachs lesion in a rabbit model

Hydration kinetics of calcium sulphate hemihydrate modified by water-soluble polymers

Hydration kinetics of calcium sulphate hemihydrate modified by water-soluble polymers

Improvement of mechanical strength and osteogenic potential of calcium sulfate-based hydroxyapatite 3-dimensional printed scaffolds by ε-polycarbonate coating

Powder-based three-dimensional (3D) printing is an excellent method to fabricate complex-shaped scaffolds for tissue engineering. However, their lower mechanical strength restricts their application in bone tissue engineering. Here, we created a 3D-printed scaffold coated with a ε-polycaprolactone (PCL) polymer solution (5 and 10 w/v %) to improve the mechanical strength of the scaffold. The 3D scaffold was fabricated from calcium sulfate hemihydrate powder (CaSO4-1/2 H2O), transformed into hydroxyapatite (HAp) by treatment with a hydrothermal reaction in an NH4H2PO4 solution. The surface properties and composition of the scaffold were evaluated using scanning electron microscopy and X-ray diffraction analysis. We demonstrated that the 3D scaffold coated with PCL had an improved mechanical modulus. Coating with 5 and 10% PCL increased the compressive strength significantly, by about 2-fold and 4-fold, respectively, compared with that of uncoated scaffolds. However, the porosity was reduced significantly by coating with 10% PCL. In vitro biological evaluation demonstrated that MG-63 cells adhered well and proliferated on the 3D scaffold coated with PCL, and the scaffold was not cytotoxic. In addition, alkaline phosphatase activity and real time polymerase chain reaction demonstrated that osteoblast differentiation also improved in the PCL-coated 3D scaffolds. These results indicated that PCL polymer coating could improve the compressive strength and biocompatibility of 3D HAp scaffolds for bone tissue engineering applications.