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Optimizing the specific surface area of fly ash-based sorbents for flue gas desulfurization

Lee KT, Bhatia S, Mohamed AR, Chu KH

Chemosphere, 2006 Jan;62(1):89-96.
PMID: 15996711

High performance sorbents for flue gas desulfurization can be synthesized by hydration of coal fly ash, calcium sulfate, and calcium oxide. In general, higher desulfurization activity correlates with higher sorbent surface area. Consequently, a major aim in sorbent synthesis is to maximize the sorbent surface area by optimizing the hydration conditions. This work presents an integrated modeling and optimization approach to sorbent synthesis based on statistical experimental design and two artificial intelligence techniques: neural network and genetic algorithm. In the first step of the approach, the main and interactive effects of three hydration variables on sorbent surface area were evaluated using a full factorial design. The hydration variables of interest to this study were hydration time, amount of coal fly ash, and amount of calcium sulfate and the levels investigated were 4-32 h, 5-15 g, and 0-12 g, respectively. In the second step, a neural network was used to model the relationship between the three hydration variables and the sorbent surface area. A genetic algorithm was used in the last step to optimize the input space of the resulting neural network model. According to this integrated modeling and optimization approach, an optimum sorbent surface area of 62.2m(2)g(-1) could be obtained by mixing 13.1g of coal fly ash and 5.5 g of calcium sulfate in a hydration process containing 100ml of water and 5 g of calcium oxide for a fixed hydration time of 10 h.

Matched MeSH terms: Calcium Compounds/chemistry*
Fulltext Treatment of Autosomal Dominant Hypocalcemia Type 1 With the Calcilytic NPSP795 (SHP635)

Roberts MS, Gafni RI, Brillante B, Guthrie LC, Streit J, Gash D, et al.

J. Bone Miner. Res., 2019 09;34(9):1609-1618.
PMID: 31063613 DOI: 10.1002/jbmr.3747

Autosomal dominant hypocalcemia type 1 (ADH1) is a rare form of hypoparathyroidism caused by heterozygous, gain-of-function mutations of the calcium-sensing receptor gene (CAR). Individuals are hypocalcemic with inappropriately low parathyroid hormone (PTH) secretion and relative hypercalciuria. Calcilytics are negative allosteric modulators of the extracellular calcium receptor (CaR) and therefore may have therapeutic benefits in ADH1. Five adults with ADH1 due to four distinct CAR mutations received escalating doses of the calcilytic compound NPSP795 (SHP635) on 3 consecutive days. Pharmacokinetics, pharmacodynamics, efficacy, and safety were assessed. Parallel in vitro testing with subject CaR mutations assessed the effects of NPSP795 on cytoplasmic calcium concentrations (Ca2+i ), and ERK and p38MAPK phosphorylation. These effects were correlated with clinical responses to administration of NPSP795. NPSP795 increased plasma PTH levels in a concentration-dependent manner up to 129% above baseline (p = 0.013) at the highest exposure levels. Fractional excretion of calcium (FECa) trended down but not significantly so. Blood ionized calcium levels remained stable during NPSP795 infusion despite fasting, no calcitriol supplementation, and little calcium supplementation. NPSP795 was generally safe and well-tolerated. There was significant variability in response clinically across genotypes. In vitro, all mutant CaRs were half-maximally activated (EC50 ) at lower concentrations of extracellular calcium (Ca2+o ) compared to wild-type (WT) CaR; NPSP795 exposure increased the EC50 for all CaR activity readouts. However, the in vitro responses to NPSP795 did not correlate with any clinical parameters. NPSP795 increased plasma PTH levels in subjects with ADH1 in a dose-dependent manner, and thus, serves as proof-of-concept that calcilytics could be an effective treatment for ADH1. Albeit all mutations appear to be activating at the CaR, in vitro observations were not predictive of the in vivo phenotype or the response to calcilytics, suggesting that other parameters impact the response to the drug. © 2019 American Society for Bone and Mineral Research.

Matched MeSH terms: Calcium Compounds/adverse effects; Calcium Compounds/pharmacokinetics; Calcium Compounds/therapeutic use*
Fulltext Alkaline phosphatase activity assessment of two endodontic materials: a preliminary study

Rajan, S., Awang, H., Pooi, A.H., Hassan, H., Devi, S.

Ann Dent, 2008;15(1):5-10.
MyJurnal

Objective: An in vitro assessment of MG-63 human osteosarcoma cells' alkaline phosphatase (ALP) activity when in contact with calcium hydroxide powder (CH), paste (CHP) and grey mineral trioxide aggregate (MTA). Methods: MG-63 cells were seeded to the three selected materials for durations of 0.25, 0.5, 1, 24, 48 and 72 hours. BCIP-NBT assay was used and ALP activity quantified using ELISA reader at 410 nm. Results: The overall analysis for ALP activity indicated significant interaction between test materials and control (maintenance medium). Subsequently, the test materials were paired and analysed for initial (0.25, 0.5, 1 hour) and delayed response (24, 48 and 72 hours). During the initial response, CH exhibited an increased ALP activity compared to MTA. This interaction was not dependant on duration. The delayed response exhibited elevated ALP activity with CHP when compared to MTA and CH. The interaction of CHP was dependant on duration. Conclusion: All three materials exhibited increased ALP activity.

Matched MeSH terms: Calcium Compounds
Perovskite-structured PbTiO3 thin films grown from a single-source precursor

Mansoor MA, Ismail A, Yahya R, Arifin Z, Tiekink ER, Weng NS, et al.

Inorg Chem, 2013 May 20;52(10):5624-6.
PMID: 23627942 DOI: 10.1021/ic302772b

Perovskite-structured lead titanate thin films have been grown on FTO-coated glass substrates from a single-source heterometallic molecular complex, [PbTi(μ2-O2CCF3)4(THF)3(μ3-O)]2 (1), which was isolated in quantitative yield from the reaction of tetraacetatolead(IV), tetrabutoxytitanium(IV), and trifluoroacetic acid from a tetrahydrofuran solution. Complex 1 has been characterized by physicochemical methods such as melting point, microanalysis, FTIR, (1)H and (19)F NMR, thermal analysis, and single-crystal X-ray diffraction (XRD) analysis. Thin films of lead titanate having spherical particles of various sizes have been grown from 1 by aerosol-assisted chemical vapor deposition at 550 °C. The thin films have been characterized by powder XRD, scanning electron microscopy, and energy-dispersive X-ray analysis. An optical band gap of 3.69 eV has been estimated by UV-visible spectrophotometry.

Matched MeSH terms: Calcium Compounds
Fulltext Influence of discrete fibers and mesh elements on the behaviour of lime stabilized soil

Kaniraj, Shenbaga R., Fung, Y. C.

Pertanika Journal of Science & Technology, 2018;26(4):1547-1570.
MyJurnal

Addition of chemical binders such as lime and cement improves the strength and stiffness
of fine grained soils. However, the treated soils exhibit brittle stress-strain behaviour.
Inclusion of randomly oriented discrete fibers in the soil-binder mixture changes its brittle
behaviour into ductile behaviour. Most synthetic fibers, however, tend to get entangled
and cannot be easily separated from one another. Therefore, it is difficult to realize soilbinder-
fiber mixtures in which the fibers are distributed uniformly throughout the mass.
This issue has been an impediment in the utilization of the positive modification in the
behaviours of soils and soil-binder mixtures by the fibers. The present study aims to address
the limitations in using fibers as soil reinforcement. Further, it also aims to investigate
the use of synthetic mesh or net elements as an alternative type of soil reinforcement.
The paper presents the experimental study on a fine grained soil. Lime has been chosen
as the binder due to its low cost and the scarcity of fiber reinforced soil studies in which
lime has been used as a binder. The main experimental program is a series of unconfined
compression tests on samples prepared using untreated soil, soil-reinforcement mixture,
soil-lime mixture, and soil-lime-reinforcement mixture. The lime treated samples were
cured up to 120 days at laboratory temperature. The results demonstrate the combinational
effects of lime and discrete reinforcement
elements on the behaviour and mechanical
properties of the soil. The performances of
the fiber and mesh element reinforcements
have also been compared.

Matched MeSH terms: Calcium Compounds
Fulltext Effect of ZnO on the physical properties and optical band gap of soda lime silicate glass

Zaid MH, Matori KA, Aziz SH, Zakaria A, Ghazali MS

Int J Mol Sci, 2012;13(6):7550-8.
PMID: 22837711 DOI: 10.3390/ijms13067550

This manuscript reports on the physical properties and optical band gap of five samples of soda lime silicate (SLS) glass combined with zinc oxide (ZnO) that were prepared by a melting and quenching process. To understand the role of ZnO in this glass structure, the density, molar volume and optical band gaps were investigated. The density and absorption spectra in the Ultra-Violet-Visible (UV-Visible) region were recorded at room temperature. The results show that the densities of the glass samples increased as the ZnO weight percentage increased. The molar volume of the glasses shows the same trend as the density: the molar volume increased as the ZnO content increased. The optical band gaps were calculated from the absorption edge, and it was found that the optical band gap decreased from 3.20 to 2.32 eV as the ZnO concentration increased.

Matched MeSH terms: Calcium Compounds/chemistry*
Efficacy of Biodentine and Mineral Trioxide Aggregate in Primary Molar Pulpotomies-A Systematic Review and Meta-Analysis With Trial Sequential Analysis of Randomized Clinical Trials

Nagendrababu V, Pulikkotil SJ, Veettil SK, Jinatongthai P, Gutmann JL

J Evid Based Dent Pract, 2019 03;19(1):17-27.
PMID: 30926099 DOI: 10.1016/j.jebdp.2018.05.002

OBJECTIVES: Pulpotomy is the favored treatment for pulp exposure in carious primary teeth. This review aimed to compare the success rates of biodentine (BD) and mineral trioxide aggregate (MTA) pulpotomies in primary molars using meta-analysis (MA) and trial sequential analysis (TSA) and also to assess the quality of the results by Grading of Recommendations, Assessment, Development and Evaluation (GRADE).
METHODS: PubMed, EBSCOhost, and Scopus databases were searched. Additional searching was performed in clinical trial registry, reference lists of systematic reviews, and textbooks. Randomized clinical trials (RCTs) published in the English language through October 2017 comparing the success of pulpotomies in vital primary molars with a follow-up of at least 6 months were selected. Study selection, data extraction, and risk of bias assessment were performed. MA by random effects model, TSA, and GRADE were performed.
RESULTS: Eight RCTs (n = 474) were included. Two RCTs had low risk of bias. No significant difference was observed between MTA and BD in clinical success at 6 months (risk ratio [RR], 1.00; 95% confidence interval [95% CI], 0.97-1.02; I2 = 0%), 12 months (RR, 1.00; 95% CI, 0.96-1.05; I2 = 0%), and 18 months (RR, 1.00; 95% CI, 0.93-1.08; I2 = 0%). No difference was observed in radiographic success at follow-up of 6 months (RR, 0.99; 95% CI, 0.96-1.02; I2 = 0%), 12 months (RR, 1.02; 95% CI, 0.47-2.21; I2 = 0%), and 18 months (RR, 1.02; 95% CI, 0.91-1.15; I2 = 0%). TSA indicated lack of firm evidence for the results of the meta-analytic outcomes on clinical and radiographic success. GRADE assessed the evidence from the MA comparing the effect of MTA and BD in pulpotomy to be of low quality.
CONCLUSION: BD and MTA have similar clinical and radiographic success rates based on limited and low-quality evidence. Future high-quality RCTs between MTA and BD is required to confirm the evidence.

Matched MeSH terms: Calcium Compounds
Transesterification of palm oil to methyl ester on activated carbon supported calcium oxide catalyst

Wan Z, Hameed BH

Bioresour Technol, 2011 Feb;102(3):2659-64.
PMID: 21109428 DOI: 10.1016/j.biortech.2010.10.119

In this study, methyl ester (ME) was produced by transesterification of palm oil (CPO) (cooking grade) using activated carbon supported calcium oxide as a solid base catalyst (CaO/AC). Response surface methodology (RSM) based on central composite design (CCD) was used to optimize the effect of reaction time, molar ratio of methanol to oil, reaction temperature and catalyst amount on the transesterification process. The optimum condition for CPO transesterification to methyl ester was obtained at 5.5 wt.% catalyst amount, 190°C temperature, 15:1 methanol to oil molar ratio and 1 h 21 min reaction time. At the optimum condition, the ME content was 80.98%, which is well within the predicted value of the model. Catalyst regeneration studies indicate that the catalyst performance is sustained after two cycles.

Matched MeSH terms: Calcium Compounds/chemistry*
Utilization of waste crab shell (Scylla serrata) as a catalyst in palm olein transesterification

Boey PL, Maniam GP, Hamid SA

J Oleo Sci, 2009;58(10):499-502.
PMID: 19745576

Aquaculture activity has increased the population of crab, hence increasing the generation of related wastes, particularly the shell. In addition, the number of molting process in crabs compounds further the amount of waste shell generated. As such, in the present work, the application of the waste crab shell as a source of CaO in transesterification of palm olein to biodiesel (methyl ester) was investigated. Preliminary XRD results revealed that thermally activated crab shell contains mainly CaO. Parametric study has been investigated and optimal conditions were found to be methanol/oil mass ratio, 0.5:1; catalyst amount, 4 wt. %; and reaction temperature, 338 K. As compared to laboratory CaO, the catalyst from waste crab shell performs well, thus creating another low-cost catalyst source for producing biodiesel as well as adding value to the waste crab shell. Reusability of crab shell CaO has also been studied and the outcome confirmed that the catalyst is capable to be reutilized up to 11 times, without any major deterioration.

Matched MeSH terms: Calcium Compounds/chemistry
Biodiesel production via transesterification of palm olein using waste mud crab (Scylla serrata) shell as a heterogeneous catalyst

Boey PL, Maniam GP, Hamid SA

Bioresour Technol, 2009 Dec;100(24):6362-8.
PMID: 19666218 DOI: 10.1016/j.biortech.2009.07.036

A recent rise in crab aquaculture activities has intensified the generation of waste shells. In the present study, the waste shells were utilized as a source of calcium oxide to transesterify palm olein into methyl esters (biodiesel). Characterization results revealed that the main component of the shell is calcium carbonate which transformed into calcium oxide when activated above 700 degrees C for 2 h. Parametric studies have been investigated and optimal conditions were found to be methanol/oil mass ratio, 0.5:1; catalyst amount, 5 wt.%; reaction temperature, 65 degrees C; and a stirring rate of 500 rpm. The waste catalyst performs equally well as laboratory CaO, thus creating another low-cost catalyst source for producing biodiesel. Reusability results confirmed that the prepared catalyst is able to be reemployed up to 11 times. Statistical analysis has been performed using a Central Composite Design to evaluate the contribution and performance of the parameters on biodiesel purity.

Matched MeSH terms: Calcium Compounds/chemistry
Fulltext Compositions and antimicrobial properties of binary ZnO-CuO nanocomposites encapsulated calcium and carbon from Calotropis gigantea targeted for skin pathogens

Govindasamy GA, Mydin RBSMN, Sreekantan S, Harun NH

Sci Rep, 2021 01 08;11(1):99.
PMID: 33420110 DOI: 10.1038/s41598-020-79547-w

Calotropis gigantea (C. gigantea) extract with an ecofriendly nanotechnology approach could provide promising antimicrobial activity against skin pathogens. This study investigates the antimicrobial capability of green synthesized binary ZnO-CuO nanocomposites from C. gigantea against non-MDR (Staphylococcus aureus and Escherichia coli) and MDR (Klebsiella pneumoniae, Pseudomonas aeruginosa and methicillin-resistant S. aureus) skin pathogens. Scanning electron microscopy and transmission electron microscopy revealed the size and shape of B3Z1C sample. Results of X-ray powder diffraction, energy-dispersive spectroscopy, FTIR and UV-Vis spectroscopy analyses confirmed the presence of mixed nanoparticles (i.e., zinc oxide, copper oxide, carbon and calcium) and the stabilising phytochemical agents of plant (i.e., phenol and carbonyl). Antimicrobial results showed that carbon and calcium decorated binary ZnO-CuO nanocomposites with compositions of 75 wt% of ZnO and 25 wt% CuO (B3Z1C) was a strong bactericidal agent with the MBC/MIC ratio of ≤ 4 and ≤ 2 for non-MDR and MDR pathogens, respectively. A significant non-MDR zone of inhibitions were observed for BZC by Kirby-Bauer disc-diffusion test. Further time-kill observation revealed significant fourfold reduction in non-MDR pathogen viable count after 12 h study period. Further molecular studies are needed to explain the biocidal mechanism underlying B3Z1C potential.

Matched MeSH terms: Calcium Compounds/pharmacology*; Calcium Compounds/chemistry*
Advances in Photocatalytic CO₂ Reduction with Water: A Review

Nahar S, Zain MFM, Kadhum AAH, Hasan HA, Hasan MR

Materials (Basel), 2017 Jun 08;10(6).
PMID: 28772988 DOI: 10.3390/ma10060629

In recent years, the increasing level of CO₂ in the atmosphere has not only contributed to global warming but has also triggered considerable interest in photocatalytic reduction of CO₂. The reduction of CO₂ with H₂O using sunlight is an innovative way to solve the current growing environmental challenges. This paper reviews the basic principles of photocatalysis and photocatalytic CO₂ reduction, discusses the measures of the photocatalytic efficiency and summarizes current advances in the exploration of this technology using different types of semiconductor photocatalysts, such as TiO₂ and modified TiO₂, layered-perovskite Ag/ALa₄Ti₄O15 (A = Ca, Ba, Sr), ferroelectric LiNbO₃, and plasmonic photocatalysts. Visible light harvesting, novel plasmonic photocatalysts offer potential solutions for some of the main drawbacks in this reduction process. Effective plasmonic photocatalysts that have shown reduction activities towards CO₂ with H₂O are highlighted here. Although this technology is still at an embryonic stage, further studies with standard theoretical and comprehensive format are suggested to develop photocatalysts with high production rates and selectivity. Based on the collected results, the immense prospects and opportunities that exist in this technique are also reviewed here.

Matched MeSH terms: Calcium Compounds
Fulltext Tunable Open Circuit Voltage by Engineering Inorganic Cesium Lead Bromide/Iodide Perovskite Solar Cells

Ng CH, Ripolles TS, Hamada K, Teo SH, Lim HN, Bisquert J, et al.

Sci Rep, 2018 02 06;8(1):2482.
PMID: 29410450 DOI: 10.1038/s41598-018-20228-0

Perovskite solar cells based on series of inorganic cesium lead bromide and iodide mixture, CsPbBr3-xI x , where x varies between 0, 0.1, 0.2, and 0.3 molar ratio were synthesized by two step-sequential deposition at ambient condition to design the variations of wide band gap light absorbers. A device with high overall photoconversion efficiency of 3.98 % was obtained when small amount of iodide (CsPbBr2.9I0.1) was used as the perovskite and spiro-OMeTAD as the hole transport material (HTM). We investigated the origin of variation in open circuit voltage, Voc which was shown to be mainly dependent on two factors, which are the band gap of the perovskite and the work function of the HTM. An increment in Voc was observed for the device with larger perovskite band gap, while keeping the electron and hole extraction contacts the same. Besides, the usage of bilayer P3HT/MoO3 with deeper HOMO level as HTM instead of spiro-OMeTAD, thus increased the Voc from 1.16 V to 1.3 V for CsPbBr3 solar cell, although the photocurrent is lowered due to charge extraction issues. The stability studies confirmed that the addition of small amount of iodide into the CsPbBr3 is necessarily to stabilize the cell performance over time.

Matched MeSH terms: Calcium Compounds
Exposure to Pb-halide perovskite nanoparticles can deliver bioavailable Pb but does not alter endogenous gut microbiota in zebrafish

Patsiou D, Del Rio-Cubilledo C, Catarino AI, Summers S, Mohd Fahmi A, Boyle D, et al.

Sci Total Environ, 2020 May 01;715:136941.
PMID: 32041050 DOI: 10.1016/j.scitotenv.2020.136941

Lead-halide perovskite nanoparticles (NPs) are a new technology, and investigation of toxicity is of considerable importance due to the potential lead (Pb) release into the environment. The aim of the study was to investigate aqueous and dietary toxicity of Pb-halide perovskite NP and Pb in zebrafish Danio rerio. Perovskite NP toxicity was evaluated in zebrafish by mortality, gene expression, histopathology, and phylogenetic analysis of gut microbiota. Zebrafish larvae were exposed to five Pb-halide perovskite NPs in parallel with Pb(NO3)2 exposures, and zebrafish adults were exposed to the three perovskite NPs that caused the strongest effect and Pb(NO3)2. No median lethal concentration (LC50) was observed for zebrafish larvae exposed to up to 200 mg/L of perovskite NPs for 96 h. Mortality, metallothionein 2 (mt2) and δ-aminolevulinic acid dehydratase (ala-d) gene expression (24-h exposure) in zebrafish larvae after aqueous perovskite NPs exposures did not differ from total Pb concentration - response curves. The lack of differences in mortality and gene expression between perovskite NPs and soluble Pb after aqueous exposure suggest that toxicity from perovskite NPs can be attributed to bioavailable Pb rather than nano-specific effects. Induction of mt2 and reduction of ala-d expression levels in liver tissues showed Pb bioavailability after 2-d and 4-d dietary exposure to perovskite-spiked feeds. Changes in gut microbiota of adult zebrafish were detected after 14-d exposure to Pb-spiked food, but no changes were detected from perovskite-NP spiked food. The phylogenetic analysis identified different microbiome profiles of Pb-fed fish compared to perovskite-fed fish suggesting a different mechanism of toxicity. Exposure to Pb-halide perovskite NPs led to absorption of Pb likely from release of Pb ions rather than absorption of NPs. Pb-halide perovskite NPs can release bioavailable Pb and this needs to be considered during the development of this technology.

Matched MeSH terms: Calcium Compounds
Effect of annealing temperature on the microstructure and dielectric properties of Ba0.6Sr0.4TiO3 Ttin films prepared by sol-gel process

Dewi R, Ibrahim N, Talib I, Ibarahim Z

Sains Malaysiana, 2008;37:233-237.

Thin films of barium strontium titanate (Ba0.6Sr0.4TiO3) perovskite system are promising candidates for microelectronic devices that can be integrated with semiconductor technology. Ba0.6Sr0.4TiO3 thin films have been prepared onto BST/TiO2/RuO2/SiO2/Si substrate using the spin coating and sol-gel process. Then the samples were subsequently annealed at 600oC, 650oC and 700oC for 60 minutes in air. The microstructure and dielectric properties show that the crystallization improved as the annealing temperature was increased. All of the films have nanometer grain size. The average grain size of the films increased as the temperature was increased. The dielectric constant and ac conductivity of the films also increased as the average grain size increased. These results showed that the microstructure and dielectric properties depend on the annealing temperature.

Matched MeSH terms: Calcium Compounds
Outcome of full pulpotomy in mature permanent molars using 3 calcium silicate-based materials: A parallel, double blind, randomized controlled trial

Taha NA, Al-Rawash MH, Imran ZA

Int Endod J, 2022 May;55(5):416-429.
PMID: 35152464 DOI: 10.1111/iej.13707

AIM: The aim of the study was to compare the outcome of full pulpotomy using 2 calcium silicate-based materials compared with mineral trioxide aggregate (MTA) in symptomatic mature permanent teeth with carious pulp exposure.
METHODOLOGY: This study was designed as a parallel, double blind, randomized controlled trial where symptomatic mature permanent teeth with carious pulp exposure meeting the inclusion criteria were randomly treated with full pulpotomy using one of 3 calcium silicate-based materials (ProRoot MTA, Biodentine and TotalFill). Full pulpotomy was performed, and haemostasis was achieved via a cotton pellet moistened with 2.5% NaOCl. A 3-mm layer of the calcium silicate-based material was randomly placed as the pulpotomy agent through a block randomization process followed by a resin-based composite restoration. Postoperative periapical radiograph was taken. Clinical and radiographic evaluation were completed after 6 months and 1 year. The patient and evaluator were blinded to the type of materials used. Pain levels were scored preoperatively and 7 days after treatment. Effect of potential prognosis factors including gender, age, diagnosis, bleeding time and type of caries were also analysed.
RESULTS: One hundred and sixty-four teeth in 146 patients received full pulpotomy and were randomly assigned to either the tested or control material through block randomization technique (50 MTA, 50 Biodentine and 64 TotalFill). The age ranged from 10 to 70 years. The diagnosis was irreversible pulpitis in 112 teeth (72%) and reversible pulpitis in 28 teeth (28%). The majority of patients presented with severe pain, during the first week 96.9% reported complete relief of pain or mild pain. Four cases had immediate failure. At 6 months the overall success rate was 92.2%, over 1 year 156/164 teeth attended follow-up with 12 failures (2 restorative failures and 10 endodontic failures), the overall success of pulpotomy at 1 year was 92.3% (144/156); 91.8% in MTA, 93.3% in Biodentine and 91.9% in TotalFill with no significant difference amongst the groups and no side effects observed. No significant association was evident between outcome and the investigated variables.
CONCLUSIONS: The 1-year success rate of full pulpotomy did not differ significantly between Biodentine pulpotomy, TotalFill pulpotomy, and MTA pulpotomy. The study was registered with clinical trials; registration number (NCT04345263).

Matched MeSH terms: Calcium Compounds/therapeutic use
Bioactivity and Cell Compatibility of β-Wollastonite Derived from Rice Husk Ash and Limestone

Shamsudin R, Abdul Azam F', Abdul Hamid MA, Ismail H

Materials (Basel), 2017 Oct 17;10(10).
PMID: 29039743 DOI: 10.3390/ma10101188

The aim of this study was to prepare β-wollastonite using a green synthesis method (autoclaving technique) without organic solvents and to study its bioactivity. To prepare β-wollastonite, the precursor ratio of CaO:SiO₂ was set at 55:45. This mixture was autoclaved for 8 h and later sintered at 950 °C for 2 h. The chemical composition of the precursors was studied using X-ray fluorescence (XRF), in which rice husk ash consists of 89.5 wt % of SiO₂ in a cristobalite phase and calcined limestone contains 97.2 wt % of CaO. The X-ray diffraction (XRD) patterns after sintering showed that only β-wollastonite was detected as the single phase. To study its bioactivity and degradation properties, β-wollastonite samples were immersed in simulated body fluid (SBF) for various periods of time. Throughout the soaking period, the molar ratio of Ca/P obtained was in the range of 1.19 to 2.24, and the phase detected was amorphous calcium phosphate, which was confirmed by scanning electron microscope with energy dispersive X-ray analysis (SEM/EDX) and XRD. Fourier-transform infrared spectroscopy (FTIR) analysis indicated that the peaks of the calcium and phosphate ions increased when an amorphous calcium phosphate layer was formed on the surface of the β-wollastonite sample. A cell viability and proliferation assay test was performed on the rice husk ash, calcined limestone, and β-wollastonite samples by scanning electron microscope. For heavy metal element evaluation, a metal panel that included As, Cd, Pb, and Hg was selected, and both precursor and β-wollastonite fulfilled the requirement of an American Society for Testing and Materials (ASTM F1538-03) standard specification. Apart from that, a degradation test showed that the loss of mass increased incrementally as a function of soaking period. These results showed that the β-wollastonite materials produced from rice husk ash and limestone possessed good bioactivity, offering potential for biomedical applications.

Matched MeSH terms: Calcium Compounds
Effect of Intracanal Medicaments on the Bond Strength of Bioceramic Root Filling Materials to Oval Canals

Al-Haddad AY, Kacharaju KR, Haw LY, Yee TC, Rajantheran K, Mun CS, et al.

J Contemp Dent Pract, 2020 Nov 01;21(11):1218-1221.
PMID: 33850066

AIM: This study aimed to evaluate the effect of the prior application of intracanal medicaments on the bond strength of OrthoMTA (mineral trioxide aggregate) and iRoot SP to the root dentin.
MATERIALS AND METHODS: Thirty single-rooted mandibular premolars were standardized and prepared using ProTaper rotary files. The specimens were divided into a control group and two experimental groups receiving Diapex and Odontopaste medicament, either filled with iRoot SP or OrthoMTA, for 1 week. Each root was sectioned transversally, and the push-out bond strength and failure modes were evaluated. The data were analyzed using Kruskal Wallis and Mann-Whitney U post hoc test.
RESULTS: There was no significant difference between the bond strength of iRoot SP and OrthoMTA without medicaments and with the prior placement of Diapex (p value > 0.05). However, iRoot SP showed significantly higher bond strength with the prior placement of Odontopaste (p value < 0.05). Also, there was no association between bond strength of OrthoMTA with or without intracanal medicament (p value > 0.05) and between failure mode and root filling materials (p value > 0.05). The prominent failure mode for all groups was cohesive.
CONCLUSION: Prior application of Diapex has no effect on the bond strength of iRoot SP and OrthoMTA. However, Odontopaste improved the bond strength of iRoot SP.
CLINICAL SIGNIFICANCE: Dislodgment resistance of root canal filling from root dentin could be an indicator of the durability and prognosis of endodontic treated teeth.

Matched MeSH terms: Calcium Compounds
Fulltext Stable and null current hysteresis perovskite solar cells based nitrogen doped graphene oxide nanoribbons hole transport layer

Kim J, Mat Teridi MA, Mohd Yusoff AR, Jang J

Sci Rep, 2016 06 09;6:27773.
PMID: 27277388 DOI: 10.1038/srep27773

Perovskite solar cells are becoming one of the leading technologies to reduce our dependency on traditional power sources. However, the frequently used component poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (
PEDOT: PSS) has several shortcomings, such as an easily corroded indium-tin-oxide (ITO) interface at elevated temperatures and induced electrical inhomogeneity. Herein, we propose solution-processed nitrogen-doped graphene oxide nanoribbons (NGONRs) as a hole transport layer (HTL) in perovskite solar cells, replacing the conducting polymer
PEDOT: PSS. The conversion efficiency of NGONR-based perovskite solar cells has outperformed a control device constructed using
PEDOT: PSS. Moreover, our proposed NGONR-based devices also demonstrate a negligible current hysteresis along with improved stability. This work provides an effective route for substituting
PEDOT: PSS as the effective HTL.

Matched MeSH terms: Calcium Compounds
Fulltext Bandgap tuning of mixed organic cation utilizing chemical vapor deposition process

Kim J, Kim HP, Teridi MA, Yusoff AR, Jang J

Sci Rep, 2016 11 22;6:37378.
PMID: 27874026 DOI: 10.1038/srep37378

Bandgap tuning of a mixed organic cation perovskite is demonstrated via chemical vapor deposition process. The optical and electrical properties of the mixed organic cation perovskite can be manipulated by varying the growth time. A slight shift of the absorption band to shorter wavelengths is demonstrated with increasing growth time, which results in the increment of the current density. Hence, based on the optimized growth time, our device exhibits an efficiency of 15.86% with negligible current hysteresis.

Matched MeSH terms: Calcium Compounds

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