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Many bioactive inorganic ions such as calcium (Ca), magnesium (Mg) and silicon (Si) have been confirmed to take part in bone regeneration through promoting the secretion of osteogenesis-related growth factors. However, it is not clear about the effective concentration range and action mechanism of ion combinations on synergistically facilitating osteogenesis. Besides, it is of great significance to design a novel bioceramic that could continuously release these effective inorganic ions to match the need for bone tissue repair. Thus, in this work, the concentration level of combined Ca, Mg, Si ions beneficial to osteogenesis of bone marrow-derived mesenchymal stem cells (BMSCs) was explored by orthogonal experimental design (OED) firstly. Meanwhile, eight single-phase ceramics in CaO-MgO-SiO2 system were synthesized, and the influences of their inherent properties on ion dissolution behaviors were systematically investigated. Finally, based on the above results, three multiphase bioceramics (named C1, C2 and C3) containing calcium silicate, diopside and akermanite as crystalline phase were designed and synthesized. It was found that the ionic extracts of bioceramic C1 were just within the above effective concentration range, displaying a predetermined ability of stimulating osteogenic differentiation of BMSCs through enhancing the expression of bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF). All the results indicated that this novel multiphase bioceramic with adjustable ion dissolution behavior has a great application potential in bone tissue engineering.

A type of strontium and amorphous calcium phosphate dipped premixed injectable tricalcium silicate-based dental root canal sealer was developed as the following protocols. A powder mixture containing tricalcium silicate, strontium carbonate (6, 8, 10, and 12 wt%), zirconia (20 wt%), calcium chloride (6 wt%), and amorphous calcium phosphate (ACP) (5 wt%) was mixed with liquid polyethylene glycol 400 (PEG 400) at a liquid-to-powder ratio of 0.5 mL/g and mechanically ground using a planetary ball to obtain the premixed injectable calcium silicate-based sealer. The sealer’s physicochemical property and cytocompatibility were evaluated in vitro. Quantitative data were expressed as mean ± standard deviation, and Student's t-test or a one-way analysis of variance (ANOVA) test were carried out at significant differences with P

The purpose of this research was to study the role of genetic and silicon-induced resistance of sugarcane to Diatraea saccharalis and the effect of silicon doses on sugarcane growth and nutrient accumulation. Initially, we assessed the resistance of 28 sugarcane genotypes to Diatraea saccharalis in a greenhouse. Then, we assessed the resistance of three sugarcane genotypes showing different genetic resistance levels submitted to the application of five doses of calcium silicate (0, 5, 10, 15 and 30 t ha−1). Also, we assessed plant growth and nutrient absorption. The results show that sugarcane genotypes exhibit different levels of genetic resistance to borers and energy-cane varieties appear to be the most resistant. However, our findings suggest that silicon-induced resistance to Diatraea saccharalis on sugarcane depends more on the silicon dose applied than the genetic resistance level of genotypes. In addition, our results show that high doses (30 t ha−1) of calcium silicate may be avoided as it may reduce the absorption of important micronutrients such as zinc, manganese and boron.

β-tricalcium phosphate bioceramics suffer from a drawback of poor mechanical strength and a scarcity of capacity to regulate biological performances. In the current study, the overall performances of β-tricalcium phosphate (TCP) bioceramics were improved by incorporating calcium silicate (CS) and magnesium-strontium phosphate (MSP). During the sintering process, the MSP stabilized the β phase of TCP, and the formation of MSP melt ensured effective liquid-sintering of TCP, thus conducing to lower porosity of TCP/MSP and TCP/CS/MSP bioceramics. In comparison with the TCP bioceramics, the TCP/CS and TCP/MSP bioceramics showed lower compressive strength, while the TCP/CS/MSP bioceramics attained noticeably higher compressive strength. Due to the sustained release of therapeutical ions, the TCP/CS bioceramics enhanced in vitro early-stage osteoblastic differentiation, but compromised cell proliferation; both the TCP/MSP and TCP/CS/MSP bioceramics enhanced cell proliferation and osteoblastic differentiation, and restrained osteoclastic activities. Collectively, the TCP/CS/MSP bioceramics with optimal overall performances are promising for efficaciously treating the defects of osteoporotic bone.

Chemotherapic cancer treatment has suffered from side effects and poor target specificity. pH-triggered drug delivery systems offer the opportunity to better deliver anticancer drugs to cancer cells in a more controllable manner. Herein, we reported a facile method to synthesize Mg-doped Ca2SiO4 (CaMgSiO4) nanospheres with highly porous structures as pH-responsive drug delivery. Material characterizations confirmed the uniform Mg doping within calcium silicates. After the Mg doping, the surface area of calcium silicates increased from 185.68 m2/g to 212.71 m2/g. When incorporated with PEG surface coating, the porous CaMgSiO4 nanoparticles displayed over 50% increased doxorubicin (DOX) loading capacity compared with Ca2SiO4 nanoparticles. The pH-triggered DOX release behaviors and cytotoxicity of porous CaMgSiO4 nanoparticles were investigated. As a result, porous CaMgSiO4 nanoparticles were highly sensitive to pH stimulus and exhibited high biocompatibility and strong cancer cell killing effect (over 75%).

In this work, we have synthesised a mixture consisting of sodium calcium silicate and calcium silicate nanostructures in the presence and absence of the hydrothermal method. The synthesised products were identified utilising many techniques such as XRD, EDS, FT-IR, HR-TEM, and FE-SEM. The XRD demonstrated that the mean crystallite size of the product, which was synthesised in the absence of the hydrothermal method, is 72.71 nm. The average crystallite size of the products, which were synthesised using the hydrothermal method at 160℃ for 4, 8, and 16 h, are 44.85, 34.89, and 37.38 nm, respectively. HR-TEM confirmed that all the products consist of irregular and rod shapes. The product, which was synthesised after 8 h of hydrothermal treatment, was operated as an adsorbent for the efficient removal of toxic ions (Cd(II) and Hg(II)) from aqueous media. The maximum adsorption capacity of the adsorbent towards Hg(II) and Cd(II) ions are 177.94 and 199.20 mg/g, respectively. The removal process of the studied ions was fitted well with the pseudo-second-order kinetic model and Langmuir equilibrium isotherm. Thermodynamic parameters confirmed that the removal process of the studied ions was spontaneous, chemical, and endothermic.

Samarium doped calcium silicates ( C a 2 − x S i O 4 : x S m 3 + , (x(%) = 0.25, 0.50, 0.75, 1.00) are synthesized using cost effective natural resources such as rice husk ash and egg shell powder through solid-state reaction method. The structural, optical, and photoluminescent properties of the as-prepared samples are reported. X-ray diffraction and Rietveld refinement results confirm that monoclinic- C a 2 S i O 4 phase is stabilized at room temperature in agro-food waste derived phosphors. Differential thermal analysis data provides information about the phase transformations. Scanning electron microscope images show that the synthesized samples have spherical morphology. C a 2 S i O 4 related vibrational bands appear in the Fourier transform infrared spectrum. Optical band gap of these phosphors is found to lie in the range 3.56–3.67 eV. Agro-food wastes inherently contain titanium in trace amounts thus, the photoluminescence emission spectrum consists of bands linked to both samarium and titanium ions. Presence of titanium makes these phosphors inherently luminescent. CIE co-ordinates of these phosphors lie in the bluish-green region. These results suggest that agro-food wastes have excellent potential of being used as precursors for synthesizing visible light emitting phosphors. Moreover, present study paves the way for effectively utilizing agro-food wastes for synthesizing environment friendly and cost-effective phosphors.

The mineral formation-transition mechanism, microstructure morphology evolution, pulverization property and chemical reactivity of calcium sulpho-aluminate with sodium dopant are systematically studied with the molar ratio of CaO to Al2O3 is 0.8, the molar ratio of CaO to SiO2 is 1.5, the mass ratio of Al2O3 to SiO2 is 2.0, and the SO3 accounts for 4%. The results show that sodium dopant could promote 3CaO·3Al2O3·CaSO4, CaO·2Al2O3 and 2CaO·Al2O3·SiO2 transform into 2CaO·SiO2, CaO·Al2O3, 12CaO·7Al2O3 and 2Na2O·3CaO·5Al2O3, and it also can decrease the decomposition temperature of reactive materials and the initial phases formation temperature significantly. Sodium diffusion can destroy the clear grain boundary of calcium aluminate and calcium silicate phases, change the macro-microstructure morphology, improve the crystalline degree of the samples, and then improve the pulverization and alumina leaching property. However, excessive sodium dopant can decrease the melting temperature, inhibit the transformation process of 2CaO·SiO2 from β to γ, and then deteriorate the pulverization property significantly again.

Release of silicon (Si) from different Si sources and Si budgeting in varied types of soils are required for the exploration of sustainable rice production. Si products are shown to be effective in...

In the composition range of x= 0-15 mol%, glasses in the system 24.5Na2O.24.5CaO.6P2O5.xSrO.(45-x)SiO2 have been studied. The glasses are transparent and have an amorphous network structure when they are as prepared. Heat treated glasses, on the other hand, are transformed into opaque white glass ceramics with a highly crystalline network structure. The main well-formed crystalline species in material bioactivity were apatite (calcium phosphate, Ca3(PO4)2, wollastonite (calcium silicate, CaSiO3), and strontium calcium phosphate [Ca2Sr(PO4)2. Increasing SrO improves material crystallite and increases the host glass matrix's hardness. The modification of the apatit Ca(PO3)2 to involve Sr ions inducing Ca2Sr (PO4)2 apatite one is thought to be the cause of the change in XRD spectra, 31P NMR chemical shift, and hardness number as SrO increases. These species help to improve material properties and hardness.

Calcium silicate based materials have gained popularity in recent years due to their resemblance to mineral trioxide aggregate (MTA) and their applicability in cases where MTA is indicated. “Biodentine” is a calcium silicate based product which became commercially available (Septodont) and that was specifically designed as a “dentine replacement” material. The material is actually formulated using the MTA-based cement technology, with the improvement of some material properties. Biodentine™ is a second generation hydraulic calcium silicate material that is composed mainly of tricalcium silicate and it also contains zirconium oxide radiopacifier and some additives. It is scientifically engineered for a specific purpose to be used as a dentine replacement material. The enhanced physical and biologic properties of Biodentine™ could be attributed to the presence of finer particle size, use of zirconium oxide as radiopacifier, purity of tricalcium silicate, absence of dicalcium silicate, and the addition of calcium chloride and hydrosoluble polymer. This article is aimed to review the properties of Biodentine by exploring the research work done in this field so far.

Among the CaCO3 polymorphs, aragonite demonstrates a better performance as a filler material in the paper and plastic industries. Despite being ideal from the environmental protection perspective, the production of aragonite particles via CO2 mineralization of rocks is hindered by the difficulty in achieving high production efficiencies and purities, which, however, can be mitigated by exploiting the potential ability of chelating agents on metal ions extraction and carbonation controlling. Herein, chelating agent N,N-dicarboxymethyl glutamic acid (GLDA) was used to enhance the extraction of Ca from calcium silicate and facilitate the production of aragonite particles during the subsequent Ca carbonation. CO2 mineralization was promoted in the presence of 0.01–0.1 M GLDA at ≤ 80 °C, with the maximal CaCO3 production efficiency reached 308 g/kg of calcium silicate in 60 min using 0.03 M GLDA, which is 15.5 times higher than that without GLDA. In addition, GLDA showed excellent effects on promoting aragonite precipitation, e.g., the content of aragonite was only 5.1% in the absence of GLDA at 50 °C, whereas highly pure (> 90%, increased by a factor of 18) and morphologically uniform aragonite was obtained using ≥ 0.05 M GLDA under identical conditions. Aragonite particle morphologies could also be controlled by varying the GLDA concentration and carbonation temperature. This study proposed a carbon-negative aragonite production method, demonstrated the possibility of enhanced and controlled aragonite particle production during the CO2 mineralization of calcium silicates in the presence of chelating agents.

Calcium silicate (CS) composite bone tissue engineering scaffolds were three-dimensionally printed using titanium metallic powders as the second strengthening phase for overcoming the inherent brittleness and fast degradability. In order to promote the sintering process of all composite scaffolds, mesoporous structure was further introduced into sol-gel-derived CS powders obtaining mesoporous CS (MCS) with larger surface area. The influences of mesoporous structure, sintering temperature and Ti content have been investigated through comparisons of the final scaffold composition, microstructure, compressive strength and in vitro stability. Results showed that CS matrix materials reacted with Ti could form less degradable CaTiO3 and TiC ceramic phases under 1200 °C sintering. The MCS-Ti scaffolds presented significantly improved density and homogeneity compared to CS-Ti. Therefore, MCS-Ti3 scaffolds with the highest 30% Ti addition, possessed the biggest compressive strength of 4.11 ± 0.39 MPa. Moreover, in vitro degradation analyzations demonstrated that MCS-Ti scaffolds enhanced ability of control over the weight losses and pH values of surrounding medium, indicating promising use as an alternative composite for bone repair.

Bioceramic materials currently applied in bone repairing mainly base on calcium phosphate compounds like hydroxyapatite (HA), however, issues including slow degradation rate and insufficient bioactivity limit their efficiency in promoting bone regeneration. Calcium silicate (CS) is a promising alternative for the purpose thanks to its degradability and bioactive Si4+ release ability, while its fast degradation rate will cause pH problem and does not match the rhythm of osteogenesis. Herein, 3D composite bioceramic scaffolds were fabricated by blending different weight fractions (1:0, 3:1, 1:1, 1:3 or 0:1) of CS nanofibers (CSNFs) and HA nanowires (HANWs) via steps of fiber-dispersing, freeze-drying and sintering. With subsequent polymer coating, the porous structure and mechanical properties of the CSNF/HANW scaffolds were improved and scaffold performances were further regulated in dependence on the hydrophobicity/hydrophilicity and degradation rates of the polymers. Poly( l -lactide) (PLLA), poly(lactide-co-caprolactone) (PLCL) and gelatin were applied as the polymer coating. It was found that PLLA- and PLCL-coating would slow down the scaffold degradation and ion release rate compared to the gelatin-coating, while the increasing fraction of CSNFs would accelerate these events to increase medium pH due to the alkalinity of the bioceramic material. Finally, proliferation and osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs) achieved desirable outcomes on gelatin-coated CSNF/HANW scaffolds with their fractions of 1:1 and 1:3, strongly suggesting the potential of these scaffolds for bone regeneration.

Silicon nanotubes (SNTs) are very attractive in the fields of energy, catalysis, and sensors, but a facile template- and/or catalyst-free preparation method is still absent. Herein, we study a controllable and cost-effective approach for preparing SNTs by electrochemically reducing layer-structured calcium silicate (CaSiO3) in molten CaCl2/NaCl without any template and catalyst. The underlying mechanism of the SNT formation is uncovered: the layer-structured CaSiO3 is first electrochemically exfoliated into SiOx (0 < x < 2) sheets while releasing CaO into the molten salts, and then the SiOx sheets are electrochemically reduced and simultaneously crimped into SNTs. The diameter (120-312 nm) and wall thickness (∼40 nm) of the SNTs can be tailorable by manipulating the reduction potential between -1.28 and -1.48 V (vs Ag/AgCl). Lastly, the electrolytic SNTs show a high lithium storage capacity of 3737 mAh g-1 at 0.2 A g-1, a high rate capability of 1371 mA h g-1 at 10 A g-1, and stable cycling with a capacity of 974 mAh g-1 after 600 cycles at 1 A g-1. Overall, the template- and catalyst-free electrochemical method provides a straightforward and facile way to prepare SNTs with a brand-new mechanism that can be applied to other tubular structure materials.

The removal of boron from silicon is a crucial step for silicon purification by the metallurgical route. The mechanism of boron removal was investigated by a combined method of using calcium silicate slag containing CaCl2 and O2 gas blowing. It is proved both experimentally and theoretically that the combined refining method is favorable for boron removal from silicon and shows a significantly enhanced boron removal. Thermodynamic calculations show that in addition to borate, a gaseous BOCl species is generated during the processing by the combined refining technique. Ab initio molecular dynamics simulations of BOCl gaseous species formation show that the Si-B bond breaks and a new Si–O–B structure is formed when the oxygen is introduced into the Si–B lattice plane. The existence of chloride further leads to the breaking of the Si–O bond and ultimately generates the O–B–Cl structure that escapes from the Si lattice plane in the form of free boride BOCl.

A fundamental theory on pyrometallurgic direct smelting of waste printed circuit boards was investigated in this work. First, the effects of the Fe/SiO2 (mass ratio) and CaO/SiO2 (mass ratio) on the liquidus temperature and viscosity of slag were systematically analyzed at a PO2 value of 10–12 atm. Then, a verification experiment was carried out. Thermodynamic calculation results showed that the liquidus temperature of slag first decreased then increased as Fe/SiO2 and CaO/SiO2 were increased. At 1250°C, the viscosity of slag is lower than 0.5 Pa s in the Fe/SiO2 range of (0.8–1.2):1 and CaO/SiO2 range of (0.25–0.85):1. The verification experiment indicated that an alloy with high content copper can be obtained. Microanalysis of the alloy and slag demonstrated that the distinguishable crystal phase in the alloy mainly contained metallic copper, metallic iron, and a small amount of intermetallic compounds such as (Fe, Ni) and Ni3Sn2. The slag was mainly composed of fayalite (Fe2SiO4), calcium silicate (Ca2SiO4, CaSiO3), and gehlenite (Ca2Al2SiO7).

This five-phase, single-blind, crossover in situ trial evaluated the effects of desensitizing or anti-erosive toothpastes on dentin erosive wear and tubule occlusion. Some characteristics such as relative dentin abrasivity (RDA), viscosity (V), cytotoxicity, and fluoride and calcium (Ca) availability of the toothpastes were also tested. Samples were positioned on removable intraoral appliances from 15 volunteers (n=4), according to the groups, C-control (0 ppm fluoride), F-sodium monofluorophosphate (MFP), A-MFP and arginine+calcium carbonate, CSP-calcium sodium phosphosilicate, and CS-MFP and calcium silicate+sodium phosphate. Erosion-abrasion cycling was performed (1% citric acid, 2min, 6×/day; toothbrushing, 5s, 2×/day). Surface loss (SL) was evaluated by optical profilometry. Environmental scanning electron microscopy images (ESEM) counted the number of open dentin tubules (ODTs). Data were statistically analyzed (α=0.05). There were no significant differences in SL among groups (p=0.468). The ODT for CSP, CS, and A groups were significantly lower than the control. CSP and CS presented significantly less ODT than F, but they did not significantly differ from A. F and CS were more abrasive than all the other toothpastes; CSP was more abrasive than A, and C was the least abrasive. CSP presented higher V (p

Silicon (Si) plays an important role in crop yields and is known as a beneficial element for gramineous plants. Si sources used as fertilizers in Brazil are mainly industrial by-products and natura...

To control the shear property of a calcium silicate mold flux, we incorporated carbon (C) into it in the form of SiC. We measured the flux’s viscosity using a rotationary viscometer to quantify its shear-thinning behavior and analyzed its structure to determine its degree of polymerization. Silicon carbide had the strongest shear-thinning property at C content = 1 wt pct and had the highest shear-thinning property ever achieved in a mold flux. The degree of shear-thinning property for silicon oxy-carbide glass followed the Oswals-De Waele power law model. This mold flux will improve the quality of continuously-cast steel by providing appropriate lubrication between the mold wall and the steel shell.

The paper describes the production of an AlSi7Mg cast alloy with Li additions and the reactions of the melt with different moulding materials. It is known that Li is very reactive and tends to form various reaction products such as oxides, gases, etc., which can influence the casting quality. The aim of the research was to find a suitable way to produce such an alloy and to describe the reaction products that are formed between the melt and the moulding material and thus to find a suitable moulding material for processing Al cast alloys with Li additions. The melt was produced in an induction furnace under an inert atmosphere. After melting, 1 w/% Li was added and the melt was cast into five different mould materials consisting of graphite, steel, a CO2 sand mixture, Croning mixture and calcium silicate materials. In the last three cases, various alcohol-based coatings were also used, such as graphite, zirconium oxide-graphite coating and aluminate-graphite filler coating. The results showed that the reaction products in the form of powder on the casting surfaces and the gas porosity in the castings occurred in the cast of a calcium silicate mould and sand mould mixtures. In the case of graphite and steel moulds, the casting surfaces were not oxidised, with no reaction products, and no gas porosity.

To assess the impact of changes in slag type on the degradation of refractory linings of secondary copper smelters, the degradation behavior of direct-bonded and fused grain magnesia–chromite refractories in ZnO-containing ferrous calcium silicate slags was studied via dynamic refractory finger and static refractory crucible tests at 1200 °C under Ar atmosphere. The effect of ZnO level in the slag and refractory type on the degradation behavior was determined. A combination of microstructural and compositional characterizations of tested refractories, and thermodynamic calculations leads to comprehensive understanding of the degradation mechanism of the refractories. Based on the degradation mechanism, conclusions can be given about the prediction of lifetime of refractory lining when the slag type changes from fayalite-based to ferrous calcium silicate-based slags for secondary copper smelting.

In this work the reagent purification of aqueous solutions from sulfates with the use of red sludge of the Nikolaev alumina plant processes were investigated. This sludge, according to chemical analysis, contains a sufficiently large amount of alumina (up to 18 %) and calcium oxide (up to 10 %) and along with calcium silicate and iron oxides contains sodium and calcium aluminates. The ability of sodium aluminate to be deposited from a solution of sulfates in the form of calcium sulfoaluminates was used in the work to purify water from sulfate anions. The process takes place when treating the solution with sludge and lime suspension. It is shown that when red sludge is applied in the amount of 1–50 g/dm3 during magnesium sulfate solutions liming, water is purified from sulfate anions. The degree of water purification reaches 50–70 %. It was found that the efficiency of sulfate extraction is significantly dependent on the consumption of lime and increases slightly with increasing sludge consumption over 1 g/dm3. The dependence of the efficiency of sulfate extraction from water on their initial concentration is determined. It was found that at the initial concentration of sulfates up to 1000 mg/dm3 at the expense of lime 3–12 mg-eq/dm3 the residual concentration of sulfates decreases to 236–460 mg/dm3, and at the concentration of sulfate anions about 2000 mg/dm3 their concentration decreases to 550–830 mg/dm3 at a lime consumption of 30 mg-eq/dm3 regardless of the sludge consumption. The degree of extraction of sulfates from solutions reaches 40–73 %.

This study reports a facile method to synthesize the calcium silicate-based cement with an enhanced radiopacifying performance. Sr-substituted Ca3SiO5 (Ca3−xSrxSiO5, x = 0.0 ~ 0.2) was prepared by solid-state reaction, and its phase, hydration behavior, and radiopacity were investigated and compared with those of 10 wt% Bi2O3-added Ca3SiO5. A nearly single-phase Ca3SiO5 was synthesized at 1400 °C and the solubility limit of Sr into Ca3SiO5 was approximately 3.3 mol % (x = 0.1). The Sr substitution did not affect the size and morphology of Ca3SiO5 powder. The extent of hydration was slightly delayed in Sr-substituted Ca3SiO5, but the hydration products were the same composing of fiber-like calcium silicate hydrate (C–S–H) and plate-like calcium hydroxide (Ca(OH)2). The radiopacity of Ca3SiO5 was significantly enhanced with Sr substitution and it was slightly higher than that of Bi2O3-added Ca3SiO5 at a similar concentration. Consequently, Sr-substituted Ca3SiO5 can be a promising dental root canal filling material with an improved radiopacifying property.

This work aims to investigate the coexistence of the poly(phospho-siloxo) networks and calcium phosphates on the compressive strengths of the acid-based geopolymers obtained at room temperature. Waste fired brick and phosphoric acid were used as an aluminosilicate and chemical reagent, respectively. Calcium aluminate hydrate was prepared by mixing calcium hydroxide from the calcined eggshell and calcined bauxite. Calcium silicate hydrate was obtained by the mixture of rice husk ash and calcium hydroxide. The molar ratios CaO/Al2O3 and CaO/SiO2 in the calcium aluminate and calcium silicate hydrates are equals to 1.0. The X-ray patterns of the acid-based geopolymers indicate the broad hump structure between 18 and 38°(2θ). In addition to this broad band, those from the mixture of calcium sources show the reflection peaks of monetite and brushite. The compressive strength of the reference is 56.43 MPa. Those obtained with the addition of 10, 20, 40 and 50 g of calcined eggshell are 30.15, 22.85, 21.16 and 13.47 MPa, respectively. The ones from calcium aluminate hydrate are 32.62, 31.58, 17.83 and 16.33 MPa, respectively. Whereas those containing calcium silicate hydrate are 44.02, 42.71, 40.19 and 18.59 MPa, respectively. This work demonstrates that the formation of calcium phosphates in the structure of the acid-based geopolymers decreases the poly(phospho-siloxo) chains and therefore reduces their compressive strengths. The moderate addition of calcium silicate hydrate reduces slightly the compressive strengths of the acid-based geopolymers which can be comparable to the one of CEM II 42.5R.

The effects of the P2O5 and CaF2 contents and the basicity on the viscosity of CaO–SiO2–Al2O3–La2O3 slag systems were investigated using the rotating cylinder method during the continuous cooling process. The structural characteristics of the quenched slag samples were clarified by Fourier transform infrared and Raman spectroscopies. The results showed that the slag viscosity and break temperature gradually increased with increasing P2O5 content from 0 and 2.5 to 5 wt% at each basicity of 0.87, 1.0 or 1.17; meanwhile, the viscosity increased as the P2O5 content increased at a greater level at low basicity. The addition of CaF2 obviously reduced the viscosity and break temperature of slag. The increase in the basicity from 0.87 and 1.0 to 1.17 decreased the viscosity of the slags under the present composition range, but raised the break temperature. The maximum viscosity reduction by the basicity occurred in the slag containing 5 wt% P2O5, while the minimum occurred in the slag containing 5 wt% CaF2. P2O5 acted as a network former in the molten slag and increased the polymerization of the silicate and phosphate complex anions, corresponding to an increase in the slag viscosity. CaF2 played a major role in the depolymerization of the silicate and phosphate complex anions in this study.Kindly check and confirm the edit made in the title.The title was no problem.

Silicon (Si) is well known as a beneficial element which is extremely essential for sustained rice productivity. Therefore, an attempt was made in the present study to assess the status of plant available Si in the intensively rice growing blocks of Kanyakumari district, Tamil Nadu, India. A total of two hundred and ten geo referenced surface soil samples representing three major rice growing blocks of Kanyakumari district (42 villages @ 5 samples /village) were collected using GPS and analysed for available silicon. Overall, 52 per cent of the rice soils were low ( 95 mg kg− 1) in Si status. The available Si had significant positive correlation with soil reaction, clay and cation exchange capacity and negatively correlated with soil electrical conductivity, coarse sand, sesquioxide and iron oxide. A field experiment was conducted with graded levels of two Si sources (0, 50, 100,150,200 kg Si/ha as calcium silicate and rice husk ash) and the results showed that soil application of 150 kg Si ha− 1 as calcium silicate was sufficient to increase growth, physiological parameters, yield attributes, grain yield of rice and post harvest soil available silicon in the study area.

Purpose. To evaluate the influence of ultrasonic activation on the physicochemical properties of setting time (ST), flow (FL), dimensional change (DC), and solubility (SL) of the cements: MTA, MTA Repair HP, and Biodentine®. Materials and Methods. Two experimental groups were formed according to the cement activation protocol: without ultrasonic activation and with ultrasonic activation. Cements were manipulated according to the manufacturers’ instructions. Ultrasonic activation group was performed with an E1 insert at power 3 (24–32 kHz) for 30 s directly in the center of the cement mass. The molds for analysis of the physicochemical properties were filled out and evaluated according to specification No. 57 from ANSI/ADA. The results were analyzed using the ANOVA test (two-way), complemented by Tukey’s test (α = 0.05). The distilled water used during the solubility test was submitted to spectrometry to verify the release of calcium ions. The morphologies of the external surface and the cross-section of the samples were analyzed by means of a scanning electron microscope (SEM). Results. For the ST, ultrasonic activation reduced the values of MTA, MTA Repair HP, and Biodentine ( P < 0.05 ). For the FL, ultrasonic activation did not alter the flow of MTA ( P > 0.05 ); however, it increased the flow MTA Repair HP and Biodentine ( P < 0.05 ). For the DC, the percentage values of dimensional change were higher when there was ultrasonic activation in all repair cements ( P < 0.05 ). For SL, there was a reduction in the percentage of the values in MTA and MTA Repair HP ( P < 0.05 ); however, there was no change in the values of Biodentine ( P > 0.05 ). Ultrasonic activation favored the release of calcium ions from all cements. The SEM analysis showed, in general, that the ultrasonic activation reduced and altered the particle shape of the cement. Conclusions. The ultrasonic activation interfered in the ST, DC, FL, ultrastructural morphology, and calcium release of the repair cements. However, it did not affect the solubility of Biodentine®.

Glasses in the system 24.5Na2O·24.5CaO·6P2O5·xSrO·(45-x)SiO2 have been studied in the composition region of x = 0 - 15 mol%. The as prepared glasses are transparent and have an amorphous network structure. On the otherhand, heat treated glasses are transformed to opaque white glass ceramic characterized by their highly crystalline network structure. Crystalline apatite (calcium phosphate, Ca3(PO4)2, wollastonite (calcium silicate, CaSiO3), and strontium calcium phosphate Ca2Sr(PO4)2 are the main well-formed crystalline species played the major role in material bioactivity. Increasing SrO leads to enhancing material crystallite and enhances the hardness of the host glass matrix. The change of XRD spectra, 31P NMR chemical shift and hardness number upon increasing SrO are considered due to modification of the apatit Ca(PO3)2 to involve Sr ions inducing Ca2Sr (PO4)2 apatite one. Such species play the role in enhancing material properties and hardness.

Titanium and its alloys are widely used for medical implant applications, but their corrosion in the physiological environment leads to the discharge of metal ions, which can trigger severe health issues. In the present study, calcium silicate reinforced hydroxyapatite (HA-CS) coatings were deposited on the Ti6Al4V substrate by using atmospheric plasma spray (APS) process with an aim to improve the corrosion resistance and bioactivity. The coatings were prepared by varying the weight percentage (wt %) of calcium silicate (CS) reinforcement in hydroxyapatite (HA) as Ha/x CS (x = 0, 10, 20 wt %). The SEM analysis of the pure HA coating revealed the presence of surface microcracks, whereas HA-CS coatings displayed the crack-free surface morphology. The corrosion investigation revealed that with the progressive increment of CS content in HA coating, the corrosion resistance of HA-CS coatings improved. In addition, surface roughness, porosity, microhardness and crystallinity increased with the increase of CS content in HA. The findings of this study indicate that the development of plasma sprayed HA-CS coatings is a promising approach to improve the performance of Ti6Al4V alloy for medical implant applications.

The aim of this article was to investigate the unknown radiopacity performances of OrthoMTA and RetroMTA via means of a contemporary image analyzing methods and energy dispersive X-ray spectroscopy. Three commercial hydraulic calcium silicate-based cements and a calcium hydroxide-based paste were used. Pure-grade zirconium oxide, bismuth oxide, zinc oxide, barium sulfate, and calcium hydroxide were as references. An energy-dispersive X-ray spectroscopy instrument was used for the elemental analysis. Radiographic image data was obtained according to the International Organization for Standardization 6876-2012 specifications. The region of interest was determined for each specimen. Mean (±SD) grey values of the X-ray image data was measured with an image analyzing software. The calibration curve was created by curve-plotting software and the mean grey-values were matched versus Al values (mm Al). Data were analyzed with one-way ANOVA followed by Tukey's multiple comparison test. Spectroscopic characterization of the commercial materials was shown with assigned Carbon, oxygen, aluminum, silicon, calcium, zinc, zirconium, barium, tungsten, bismuth, and sulfur elements. The major radiopacifier/s of OrthoMTA is Bi, of RetroMTA is Zr, of BioDentine are Ba and Zr, and of ProCal is Ba. The radiopacity values of all commercial materials are significantly different (p .05). The rank of the radiopacity values: RetroMTA (3.36 ± 0.29mmAl) OrthoMTA (2.56 ± 0.19mmAl) BioDentine (2.02 ± 0.12mmAl) ProCal (1.46 ± 0.60mmAl). The study reported that the radiopacity values and spectral characterization of RetroMTA and OrthoMTA cements. The pixel-based and reproducible method could be used universally to the quantification of the radiodensity of digitally collected X-ray data.

Development and testing of catalytic filters for partial oxidation of methane to increase hydrogen production in a biomass gasification process constitute the subject of the present study. Nickel, iron and lanthanum were coated on calcium silicate filters via co-impregnation technique, and catalytic filters were characterized by ICP-MS, XPS, XRD, TEM, TGA, TPR and BET techniques. The influences of varying reaction temperature and addition of Fe or La to Ni-based catalytic filters on methane conversion, and hydrogen selectivity have been investigated in view of preliminary results obtained from reactions with 6% methane-nitrogen mixture, and catalytic filters were tested with model biogas mixtures at optimum reaction temperature of each filter which were 750 °C or 850 °C. Approximately 93% methane conversion was observed with nearly 6% methane-nitrogen mixture, and 97.5% methane conversion was obtained with model biogas containing CH4 which is 6%, CO2, CO, and N2 at 750 °C. These results indicate that calcium silicate provides a suitable base material for catalytic filters for partial oxidation of methane and biogas containing methane.

The soils in hazardous waste sites contain heavy metals which would leach into groundwater by various biotic and abiotic processes and eventually pose a threat to human health by contaminating the drinking water. In order to understand pattern of heavy metal leachability, the field conditions can be simulated by adopting various types of sequential extraction methods. In this study, an attempt was made to evaluate the effectiveness and selectivity of a sequential extraction process to determine heavy metal binding mechanisms in soils and soil treated with nano-calcium silicate (NCS). A five-step sequential extraction (SE) procedure was adopted on four soils obtained from a sanitary dumpsite, automobile and battery work units from different localities of Bangalore and a steel plant commissioned at Toranagallu, Bellary, India. The soils were mixed with NCS at varying range of 0.5 to 2% by dry weight of the soil. The NCS-amended soils were spiked with cadmium (Cd2+), nickel (Ni2+) and lead (Pb2+) in concentrations to the tune of 3000 mg/kg. It has been observed that there seems to be a gradual increase in binding ability for the targeted heavy metals when soils were amended with NCS compared to untreated soils. This binding phenomenon was attributed to the presence of exchangeable ions, carbonates, oxides of iron and manganese, organic matter and residual fractions. It was noticed that the residual fractions in soils amended with NCS attenuated maximum quantity of metal ions with Pb2+ at 21.46%, followed by 18.8% for Cd2+ and 9.25% for Ni2+ compared to untreated case. Further, this work highlights the role of residual fraction in enhancing the retention capacity of soils by encapsulation of higher concentrations of contaminants. The current study corroborated the fact that the addition of NCS aids in the better encapsulation of selected heavy metal ions.

Silicon is a beneficial nutrient for the growth and production of many plant species, including tomatoes. The objective was to evaluate the influence of calcium silicate on the morphophysiological characteristics of tomatoes and the absorption of silicon, calcium, and magnesium. The experiment was conducted in a protected environment from August to December 2017, in a random block design, in a 2 x 5 factor scheme, with four repetitions. The first factor consisted of two hybrids (Ivety and Natalia) and the second factor by doses of calcium silicate (0, 150, 300, 450 and 600 kg ha-1). The fruits were evaluated for number of fruits per plant, longitudinal and transversal diameter, average fruit mass, commercial, non-commercial, and total productivity. The plants were evaluated for number of leaves, stem diameter, plant length, leaf area, membrane integrity damage, lignin content, stem and leaves dry mass, silicon accumulation and content, calcium, and magnesium contents in the leaves and in tomato fruits. The morphometric characteristics of Ivety and Natalia tomato hybrids were not altered by increasing doses of calcium silicate. The increased doses of calcium silicate influenced the non-commercial productivity of the tomato fruits, showing a reduction of this with the increased doses. Calcium silicate influenced differently in each hybrid, and it is worth noting that these results may vary in terms of genetic material and cultivation environment.

The research presented here investigates the reaction mechanism of wollastonite in situ mineral carbonation for carbon dioxide (CO2) sequestration. Because wollastonite contains high calcium (Ca) content, it was considered as a suitable feedstock in the mineral carbonation process. To evaluate the reaction mechanism of wollastonite for geological CO2 sequestration (GCS), a series of carbonation experiments were performed at a range of temperatures from 35 to 90 °C, pressures from 1500 to 4000 psi, and salinities from 0 to 90,000 mg/L NaCl. The kinetics batch modeling results were validated with carbonation experiments at the specific pressure and temperature of 1500 psi and 65 °C, respectively. The results showed that the dissolution of calcium increases with increment in pressure and salinity from 1500 to 4000 psi and 0 to 90000 mg/L NaCl, respectively. However, the calcium concentration decreases by 49%, as the reaction temperature increases from 35 to 90 °C. Besides, it is clear from the findings that the carbonation efficiency only shows a small difference (i.e., ±2%) for changing the pressure and salinity, whereas the carbonation efficiency was shown to be enhanced by 62% with increment in the reaction temperature. These findings can provide information about CO2 mineralization of calcium silicate at the GCS condition, which may enable us to predict the fate of the injected CO2, and its subsurface geochemical evolution during the CO2-fluid-rock interaction.

Samarium (Sm3+) doped sodium calcium silicate (Na2CaSiO4: NCS) phosphors have been synthesized by employing a sol-gel technique. The structural, morphological, excitation and emission spectral studies have been carried out for the as-prepared phosphors. The phase purity in synthesized NCS phosphor with cubic structure has been confirmed by X-ray diffraction (XRD) pattern. The scanning electron microscopic images depict the irregular morphology and non-uniform microcrystalline particles in synthesized phosphor. The excitation spectra of NCS: Sm3+ phosphors disclose strong absorption in UV (ultraviolet), n-UV (near UV) and blue spectral regions. The emission spectra recorded under 402 nm excitation exhibit peaks at 565, 602 and 649 nm attributed to characteristic 4f-4f transitions of Sm3+ ions. The Sm3+ concentration optimized for NCS host as 1.0 mol%, and concentration quenching phenomenon has been discussed in detail. The chromaticity coordinates (0.579, 0.419) for optimized NCS: Sm3+ phosphor lie in the pure orange region. The temperature-dependent photoluminescence studies demonstrate that luminescence intensity even at 423 and 463 K persists up to 85.4 and 79.6% of the intensity at room temperature, respectively. Above mentioned results substantiate the potentiality of NCS: Sm3+ phosphor to use as a thermally stable orange emitting component in photonic devices.

This study aimed to determine the effect of silicon and silicate salts in reducing the incidence of white rot disease, caused by Stromatinia cepivora, on onion and garlic plants. Under greenhouse conditions silicon and silicate salts was used at 0.1, 0.2 and 0.3%. Before planting, onion transplants and/or garlic cloves were dipped for 1 h in the desired concentration. After planting, stem bases of plants were supplemented with the same concentration three times intervals at 30, 60 and 90 days after planting. Data showed that successful application resulted from silicon and silicate salts was obtained at 0.3%, which significantly reduced the incidence of white rot and improved the growth of onion and garlic plants. However, there were no significant differences between some treatments at 0.1, 0.2 and/or 0.3%. Field experiments were conducted in soils naturally infested with S. cepivora for 2 years to evaluate the effect of silicon and silicate salts at 0.3% on white rot incidence as well as the mechanisms underlying the observed of disease reduction. Application of silicon and silicate salts significantly reduced the incidence of white rot disease, increased the amount of chlorophyll a, chlorophyll b, carotenoids, proline and promoted the bulbs yield of onion and garlic plants. Potassium silicate solution (Ps) and sodium meta silicate pentahydrate (Ss) were more effective treatments. Calcium silicate was the least effective treatment. Application of silicon and silicate salts resulted in the increase of soil dehydrogenase enzyme and CO2 evolution in the rhizospheric soil of onion and garlic plants. Applications of silicon and silicate salts significantly stimulated systemic defense enzymes and enhanced the expressions of some genes into proteins in onion and garlic plants. These findings suggest that silicon and silicate salts reduced the incidence of white rot disease and exerts a beneficial effect on the field-grown garlic and onion plants, providing an alternative disease management strategy.

Numbers of silicon (Si) sources have been reported in terms of their effec-tiveness to improve rice growth and yield. Moreover, it is very critical to un-derstand the efficiency of different silicon sources and their levels for satis-factory plant uptake and its performances in various types of soils. In this point of view, field experiments were conducted during kharif season of 2017-18 and 2018-19 to assess the effect of different silicon sources and levels on growth parameters of rice (Oryza sativa L.) under lateritic soil of Jharkhand, India. Silica was applied at the rate of 0, 50 and 100 kg Si ha−1 through Calcium Silicate, Fly Ash and Paddy Straw. The results indicated that the growth parameters were significantly affected by the sources and levels of Silicon. Application of calcium silicate @ 150 kg Si ha-1 was found most effective followed by Paddy Straw @ 150 kg Si ha-1 followed by Fly Ash @ 150 kg Si ha-1 compared to control (RDF). The highest growth parameters were found with calcium silicate @ 150 kg Si ha-1 in combination with RDF. Accordingly different treatments could be arranged in the order T4>T10>T7>T3>T9> T6>T2>T8>T5>T1. Si application at the level 150 kg Si ha-1 along with RDF would help in the sustainable production of rice in the later-itic soil of Jharkhand.

Bioceramics have been widely used for many years to restore and replace hard tissues including bones, teeth and mineralized matrices such as calcified cartilages at osteochondral interfaces, mainly because of their physicochemical similarity with these tissues. Calcium silicate based bioceramics have been shown to possess high bioactivity due to having high apatite-forming ability and stimulating cell proliferation, as well as biodegradability at rates appropriate to hard tissue regeneration. The outstanding biological properties of these ceramics have made them the most studied hard tissue engineering biomaterials along with calcium phosphates and bioactive glasses. Baghdadite is a calcium silicate containing zirconium ions which promotes the proliferation and differentiation of human osteoblasts and consequently increases mineral metabolism and ossification. Recently, it has attracted considerable attention in academic community and widely studied in the form of porous scaffolds, coatings, bone cement and void fillers, microspheres and nanoparticles mostly in orthopedic, dental and maxillofacial applications. This review paper is aimed to summarize and discuss the most relevant studies on the mechanical properties, apatite formation ability, dissolution behavior, and in vitro and in vivo biological properties of baghdadite as a biomaterial for hard tissue regeneration applications.

In this study, calcium silicate and sodium silicate were added to OM7347 rice seedlings grown in artificial aluminum toxicity (AlCl3) conditions. This study was carried out through two experiments to evaluate the effect of sodium silicate and calcium silicate on aluminum resistance in rice planting stage OM7347. Experiment 1, theeffects of aluminum were evaluated at three different levels (AlCl3 50, 100 and 150 mM) on plant growth. Experiment 2, sodium silicate and calcium silicate were added with a concentration of 200 mg/L to aluminumtoxic medium (AlCl3 50 and 100 mM) to evaluate the aluminum poisoning improvement effect of Si compounds. Experimental results showed that rice seedlings were very sensitive to aluminum, and a concentration of 50 mM reduced rice seedlings development. AlCl3 caused lower pH values, decreased chlorophyll a content, plant height and root length were poorly developed resulting in low fresh biomass. In addition, aluminum presentmade root cells lose their integrity and lipid peroxidation occured. However, when sodium silicate and calcium silicate were added to the cultured solution, the pH values of the solution increased, improved plant growth such as shoot height, root length, fresh biomass and especially reduced aluminum toxicity on root morphology of rice seedlings indicated by less of lipid peroxidation and maintained root cell integrity. Silicon supplementsprevented aluminum accumulation in roots and improved secondary root system, root branching.

The effects of magnesium carbonate on the setting time and compressive strength of Portland cement paste were studied when the content of magnesium carbonate was 0wt%, 0.5wt%, 1wt%, 2wt%, and 3wt% by the weight of cement. The influence mechanism was analyzed through combining with the tests of hydration heat, X-ray diffraction (XRD), differential thermal analysis-thermogravimetric analysis (DTA-TG), and scanning electron microscope (SEM). The results show that magnesium carbonate makes the setting time of cement paste shorten, and makes the compressive strengths of cement paste increase at 1 day and 7 days, but decrease at 28 days. The testing results of the heat of hydration, XRD, SEM, and DTA-TG show that magnesium carbonate promotes the formation of Ettringite (AFt) and the hydration of calcium silicate in the early stage when its content is less than 1wt%, but the addition of magnesium carbonate is unfavorable to the later hydration of Portland cement. Based on the above analysis, it is suggested that the content of magnesium carbonate is not more than 1wt%, which has good reference value for using magnesium carbonate to prepare early strength agent for cement paste.

Finger millet (Eleusine coracana) leaf blast caused by Pyricularia grisea is a common disease and results in severe yield losses. Noble element silicon (Si) effectively mitigates both biotic and abiotic stresses and is known to enhance plant resistance against fungal and bacterial pathogens. The results revealed that there are potential positive effects of silicon application in soil to suppress the blast disease in finger millet genotypes. Among various treatments, 3 g calcium silicate/kg of soil was found to be most effective in enhancing resistance to blast followed by 2 g calcium silicate/kg of soil and 1 g calcium silicate/kg of soil treatments. Silicon content in leaf, stem, and root increased significantly over non-treated plants. A significant negative correlation was observed between silicon accumulation in the plants (leaf, stem, and root) and percent disease index. Both principal component analysis and cluster analysis revealed that among 40 genotypes tested, six genotypes such as ‘Suvra’, ‘GE-2740’, ‘NO-2836’, ‘GE-320’, ‘OEB-532’, and ‘GE-1135’ showed higher silicon accumulation with enhanced plant resistance along with the desired traits. Therefore, silicon accumulating genotypes can be used for the breeding program. Further, this study confirmed the positive effect of Si in enhancing the blast resistance in finger millets through the physical barrier mechanism by inhibiting the fungal penetration and colonization in cell and it can provide an alternative eco-friendly disease management strategy.

Hybrid powder pigments based on calcium phosphates and Ca-exchange silicates (CPS) were prepared via a sequential co-precipitation method. Chemical composition of CPS and reference pigments (calcium phosphates (CP) and calcium silicates (CS)) was investigated in relation to molar ratio of substrates and pH value of reaction medium. Steel corrosion inhibition efficiency (η) for the pigments was evaluated using electrochemical noise (EN), polarization resistance (POL) and Tafel (TAF) techniques. XRD and FT-IR data indicated that CPS are mixtures of the relevant CP and CS pigments. The EN, POL and TAF data revealed a sinusoidal relation between η and P:Si molar ratio in the substrates (at pH = 8.5 or 11). The best anticorrosive features were observed for CPS prepared at Si molar excess (pH = 8.5) (ηEN = 99%, ηPOL = 73% and ηTAF = 85%). Probably, the synergistic effect was resulted by a specific content and molar ratio of Ca, P2O5 and Si in the CPS-based electrolytes.

A new synthetic procedure is described for the synthesis of calcium silicate derivatives, using natural resources such as eggshell (ES) for calcium and oil palm leaves (OPL) for silica, which do not require prepurification. The reaction is performed by directly converting two weight ratio of the precursors, ES:3OPL and ES:6OPL, to dried-powder form by heat treatment at 900 °C for two hours. The results demonstrate that the concentration of the precursors has an effect on the morphology and crystallinity of the calcium silicate derivatives, mainly Ca2SiO4 and CaSiO3. X-ray diffraction results reveal that the reaction product obtained using a 1:3 ratio is quite pure, and mainly consisted of calcium silicate in the form of Ca2SiO4. The CaSiO3 was also identified in ES:6OPL, together with a small amount of excess non-reacted crystalline silica. Furthermore, a scanning electron microscopy analysis shows that both reaction products have a coarse surface. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Comparatively few field experiments have been conducted to monitor the long-term effects of Si fertilizer amendments on the mitigation of Cd and As accumulation in rice grains. A 4-year field trial (eight growing seasons) was established in paddy fields to investigate the effects of different Si fertilizers on the mitigation of Cd and As uptake in rice cultivars. Cultivars for the spring and summer growing seasons were chosen based on their local popularity to investigate the effect of Si fertilizers on different cultivars. Average Cd concentrations in spring rice grains (0.020 ± 0.006 mg/kg) were much lower than those in summer rice grains (0.416 ± 0.370 mg/kg) regardless of rice cultivar. Spring rice grains contained slightly higher average As concentrations (0.43 ± 0.07 mg/kg) than summer rice grains (0.30 ± 0.09 mg/kg). Silicon fertilizers, except sodium silicate, significantly decreased grain Cd concentrations. Calcium silicate fertilizer substantially decreased grain Cd, by up to 55.1 ± 17.6%, and to a greater extent than that in response to Si-potash fertilizer, by up to 26.4 ± 7.9%, probably because of competition between Cd and Ca for Ca transport channels. Slow-release Si fertilizer resulted in the greatest decrease in grain Cd concentration (69.0% ± 8.6%). Slow-release fertilizer may provide a longer-term Si source and higher efficiency of use for rice than readily soluble Si. Silicon fertilizers substantially reduced Cd, but not As, concentrations in summer rice grains for a long term (eight growing seasons). Calcium silicate fertilizer reduced grain Cd concentrations more significantly than potassium silicate fertilizer. Calcium silicate fertilizer exhibited higher efficacy of Cd reduction in grains regardless of rice cultivar or growing season. Slow-release Si fertilizer showed superior ability for Cd mitigation than that of soluble Si fertilizers.

The aim of this study was to evaluate the microstructural composition, ion release, cytocompatibility, and mineralization potential of Bio-C Sealer ION+ (BCI) and EndoSequence BC Sealer HiFlow (BCHiF), compared with AH Plus (AHP), in contact with human periodontal ligament cells (hPDLCs). The sealers’ ionic composition and release were assessed using energy-dispersive spectroscopy (EDS) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. For the biological assays, hPDLCs were isolated from third molars, and sealer extracts were prepared (undiluted, 1:2, and 1:4 ratios). An MTT assay, wound-healing assay, and cell morphology and adhesion analysis were performed. Activity-related gene expression was determined using RT-qPCR, and mineralization potential was assessed using Alizarin Red staining (ARS). Statistical analyses were performed using one-way ANOVA and Tukey’s post hoc test (α

The formation and transition of calcium aluminate and calcium silicate compounds from pre-synthesized mullite in low-calcium system were systematically studied by solid-state reaction at 1350–1500 °C using XRF, XRD, FTIR, SEM and PSD methods. Ca3Al2O6, Ca12Al14O33, CaAl2O4, Ca2SiO4 and Ca2Al2SiO7 can form via direct reaction of mullite with CaO at the beginning of the reactions, then Ca12Al14O33 and Ca3Al2O6 react with mullite to form CaAl2O4 and Ca2SiO4, and finally Ca2Al2SiO7 reacts with CaO to generate Ca2SiO4 and calcium aluminate compounds as the sintering process proceeds. Elevating the sintering temperature is in favor of the formation of Ca12Al14O33, Ca3Al2O6 and Ca2Al2SiO7 at the initial reaction stage, but Ca2Al2SiO7 cannot totally transform to calcium silicate and calcium aluminate compounds in the low-calcium system, which deteriorates the pulverization performance of the final products. Increasing the calcium dosage accelerates the transformation of Ca2Al2SiO7 to Ca12Al14O33, CaAl2O4 and Ca2SiO4, which enhances the pulverization performance. If the CaO/Al2O3 molar ratio exceeds 1.4, Ca3Al2O6 will generate by the reactions of pre-formed CaAl2O4 and Ca12Al14O33 with excessive CaO.

To reduce the CO2 emissions from cement production, Portland cement (PC) is partially replaced by supplementary cementitious materials (SCM). Reactions of SCM with PC during hydration leads to the formation of Csingle bondSsingle bondH with more silicon and aluminum than in PC, which affects the stability and durability of such concrete. Therefore, it is crucial to determine the role of aluminum on Csingle bondSsingle bondH properties to predict the formed hydrate phase assemblages and their effects on durability. Aluminum sorption isotherms including very low Al concentrations have been determined for Csingle bondSsingle bondH with Ca/Si ratios from 0.6 to 1.4. Elemental measurements were performed with ICP-MS and ICP-OES. The presence of secondary phases was investigated by using thermogravimetric analysis and XRD. Higher dissolved concentrations of Al were observed at increased alkali hydroxide concentrations and thus higher pH values. High alkali hydroxide led to an increased Al(OH)4- formation, which reduced the Al uptake in Csingle bondSsingle bondH. This comparable behavior of Al and Si towards changes in pH values, points toward the uptake of aluminum within the silica chain both at low and high Ca/Si ratios. A higher Al uptake in Csingle bondSsingle bondH was observed at higher Ca/Si ratios, which indicates a stabilizing effect of calcium in the interlayer on Al uptake.

Ferrous calcium silicate (FCS) slags are reported to have high potential for use in the copper converting process. However, no phase equilibrium study has been carried out under a simulated converting gas atmosphere in the presence of SO2. In this study, under accurately controlled P(SO2) 0.4 atm and P(O2) 10−6 atm, the phase equilibria of FCS slags in a liquid/spinel/white metal/gas system were investigated for the copper converting process. The liquidus temperatures of slags in the Fe-Ca-Cu-Si-S-O system were quantified as well as the solid solubilities of Cu2O in the spinel phase. The experimental results were compared with the FactSage predictions, which provided clues for further improvement of the thermodynamic modelling. The applications of the FCS slags were further discussed and compared with iron silicate slags. The results obtained will contribute to slag development for converting operations and thermodynamic calculations.

Background Mesoporous calcium-silicate nanoparticles (MCSNs) have good prospects in the medical field due to their great physicochemical characteristics, antibacterial activity and drug delivery capacity. This study was to analyze the antibiofilm activity and mechanisms of silver (Ag) and zinc (Zn) incorporated MCSNs (Ag/Zn-MCSNs) with different percentages of Ag and Zn. Methods Ag/Zn(1:9, molar ratio)-MCSNs and Ag/Zn(9:1, molar ratio)-MCSNs were prepared and characterized. Endocytosis of nanoparticles by Enterococcus faecalis (E. faecalis) treated with Ag/Zn-MCSNs was observed using TEM to explore the antibacterial mechanisms. The antibiofilm activity of Ag/Zn-MCSNs with different ratios of Ag and Zn was tested by E. faecalis biofilm model in human roots. The human roots pretreated by different Ag/Zn-MCSNs were cultured with E. faecalis. Then, SEM and CLSM were used to observe the survival of E. faecalis on the root canal wall. Cytotoxicity of the nanoparticles was tested by CCK8 kits. Results The Ag/Zn-MCSNs release Ag+ and destroy the cell membranes to kill bacteria. The MCSNs containing Ag showed antibacterial activity against E. faecalis biofilms in different degrees, and they can adhere to dentin surfaces to get a continuous antibacterial effect. However, MTA, MCSNs and Zn-MCSNs could not disrupt the bacterial biofilms obviously. MCSNs, Ag/Zn(1:1, molar ratio)-MCSNs and Ag/Zn(1:9)-MCSNs showed no obvious cytotoxicity, while Ag-MCSNs and Ag/Zn(9:1)-MCSNs showed cytotoxicity. Zn-MCSNs can slightly promote cell proliferation. Conclusion Ag/Zn-MCSNs have good antibiofilm activity. They might achieve an appropriate balance between the antibacterial activity and cytotoxicity by adjusting the ratio of Ag and Zn. Ag/Zn-MCSNs are expected to be a new type of root canal disinfectant or sealer for root canal treatment.