Displaying publications 81 - 100 of 109 in total

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  1. Fulltext Phytogenic Synthesis of Pd-Ag/rGO Nanostructures Using Stevia Leaf Extract for Photocatalytic H2 Production and Antibacterial Studies
    Mallikarjuna K, Nasif O, Ali Alharbi S, Chinni SV, Reddy LV, Reddy MRV, et al.
    Biomolecules, 2021 01 29;11(2).
    PMID: 33572968 DOI: 10.3390/biom11020190
    Continuously increasing energy demand and growing concern about energy resources has attracted much research in the field of clean and sustainable energy sources. In this context, zero-emission fuels are required for energy production to reduce the usage of fossil fuel resources. Here, we present the synthesis of Pd-Ag-decorated reduced graphene oxide (rGO) nanostructures using a green chemical approach with stevia extract for hydrogen production and antibacterial studies under light irradiation. Moreover, bimetallic nanostructures are potentially lime lighted due to their synergetic effect in both scientific and technical aspects. Structural characteristics such as crystal structure and morphological features of the synthesized nanostructures were analyzed using X-ray diffraction and transmission electron microscopy. Analysis of elemental composition and oxidation states was carried out by X-ray photoelectron spectroscopy. Optical characteristics of the biosynthesized nanostructures were obtained by UV-Vis absorption spectroscopy, and Fourier transform infrared spectroscopy was used to investigate possible functional groups that act as reducing and capping agents. The antimicrobial activity of the biosynthesized Pd-Ag-decorated rGO nanostructures was excellent, inactivating 96% of Escherichia coli cells during experiments over 150 min under visible light irradiation. Hence, these biosynthesized Pd-Ag-decorated rGO nanostructures can be utilized for alternative nanomaterial-based drug development in the future.
    Matched MeSH terms: Calcium Compounds
  2. Fulltext Postoperative assessment of diode laser zinc oxide eugenol and mineral trioxide aggregate pulpotomy procedures in children: A comparative clinical study
    Pratima B, Chandan GD, Nidhi T, Nitish I, Sankriti M, Nagaveni S, et al.
    J Indian Soc Pedod Prev Dent, 2018 9 25;36(3):308-314.
    PMID: 30246755 DOI: 10.4103/JISPPD.JISPPD_1132_17
    Aim: The present study is an attempt to compare and evaluate postoperative assessment of diode laser zinc oxide eugenol (ZOE) pulpotomy and diode laser mineral trioxide aggregate (MTA) pulpotomy procedures in children.

    Materials and Methods: Forty carious primary molars indicated for pulpotomy within the age group of 4-9 years were selected and divided into two groups of 20 each using simple randomization, Group 1: Diode laser MTA and Group 2: Diode laser ZOE pulpotomy. The teeth were evaluated clinically for 1 year at 3, 6, and 12 months interval and radiologically for 6 and 12 months.

    Results: Clinically and radiographically, 100% teeth treated with diode laser MTA and 94% treated with diode laser ZOE were considered successful after 12-month follow-up interval. No significant difference was seen between two groups.

    Conclusion: Despite the success rate, the cost factor of diode laser and MTA could be the limiting factor in its judicious use in pulpotomy procedure.

    Matched MeSH terms: Calcium Compounds/therapeutic use*
  3. Fulltext Preparation and characterization of glass-ceramic synthesized from soda lime glass and wastewater sludge
    Zaidan Abdul Wahab, Syaharudin Zaibon, Khamirul Amin Matori, Norfarezah Hanim Edros, Thai, Ming Yeow, Mohd Zul Hilmi Mayzan, et al.
    Pertanika Journal of Science & Technology, 2010;18(2):-.
    MyJurnal
    This paper reports an alternative method for making glass-ceramic from disposal waste water
    sludge and soda lime silica (SLS) glass. The glass ceramic samples were prepared from a mixture
    of wastewater sludge and SLS glasses, melted at 1375°C for 3 hours and quenched by pouring into
    water to obtain a coarse frit. The frit glass was then crushed and sieved to 106μm before it was
    pressed to a pellet. The sintering process was performed at various temperatures between 700-
    1000°C for 2 hours and morphologically characterized with XRD, SEM, and EDX. Overall results
    showed the crystalline phase of diopside sodian-critobalite glass-ceramic is depending on thermal
    treatment process and making them attractive to industrial uses such as in construction, tiling, and
    glass-ceramic applications.
    Matched MeSH terms: Calcium Compounds
  4. Fulltext Profile of The Betel/Tobacco Quid Chewers In six Malaysian Estates
    Tan, B.S., Rosman, A., Ng, K.H., Ahmad, N.
    Ann Dent, 2000;7(1):-.
    MyJurnal
    The aim of the study was to determine the characteristics and pattern of the betel/tobacco quid chewing habit in the estate Indian community. The study was conducted in 6 randomly selected estates. It involved oral mucosal examination and an interview to solicit personal data as well as history and details of oral habits. Of a total of 618 subjects studied, 19.3 % (n= 119; 89 females and 30 males) were betel !tobacco quid chewers. The youngest age of onset of betel quid chewing is 10 years. The mean frequency of chewing quid is 4.3 times/day and the mean duration of chewing is 8.1 minutes. Initiation to the habit occur at a young age and a major role is played by family and friends in initiation to the habit. Practises of adding tobacco and lime appear to have adverse effects and are associated with higher occurrences of precancer lesions in this study (p
    Matched MeSH terms: Calcium Compounds
  5. Fulltext Reaction Mechanism of Wollastonite In Situ Mineral Carbonation for CO2 Sequestration: Effects of Saline Conditions, Temperature, and Pressure
    Kashim MZ, Tsegab H, Rahmani O, Abu Bakar ZA, Aminpour SM
    ACS Omega, 2020 Nov 17;5(45):28942-28954.
    PMID: 33225124 DOI: 10.1021/acsomega.0c02358
    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.
    Matched MeSH terms: Calcium Compounds
  6. Recent Progress on Advanced Materials for Solid-Oxide Fuel Cells Operating Below 500 °C
    Zhang Y, Knibbe R, Sunarso J, Zhong Y, Zhou W, Shao Z, et al.
    Adv Mater, 2017 Dec;29(48).
    PMID: 28628239 DOI: 10.1002/adma.201700132
    Solid-oxide fuel cells (SOFCs) are electricity generators that can convert the chemical energy in various fuels directly to the electric power with high efficiency. Recent advances in materials and related key components for SOFCs operating at ≈500 °C are summarized here, with a focus on the materials, structures, and techniques development for low-temperature SOFCs, including the analysis of most of the critical parameters affecting the electrochemical performance of the electrolyte, anode, and cathode. New strategies, such as thin-film deposition, exsolution of nanoparticles from perovskites, microwave plasma heating, and finger-like channeled electrodes, are discussed. These recent developments highlight the need for electrodes with higher activity and electrolytes with greater conductivity to generate a high electrochemical performance at lower temperatures.
    Matched MeSH terms: Calcium Compounds
  7. Removal of VOCs from gas streams with double perovskite-type catalysts
    Pan KL, Pan GT, Chong S, Chang MB
    J Environ Sci (China), 2018 Jul;69:205-216.
    PMID: 29941256 DOI: 10.1016/j.jes.2017.10.012
    Double perovskite-type catalysts including La2CoMnO6 and La2CuMnO6 are first evaluated for the effectiveness in removing volatile organic compounds (VOCs), and single perovskites (LaCoO3, LaMnO3, and LaCuO3) are also tested for comparison. All perovskites are tested with the gas hourly space velocity (GHSV) of 30,000hr-1, and the temperature range of 100-600°C for C7H8 removal. Experimental results indicate that double perovskites have better activity if compared with single perovskites. Especially, toluene (C7H8) can be completely oxidized to CO2 at 300°C as La2CoMnO6 is applied. Characterization of catalysts indicates that double perovskites own unique surface properties and are of higher amounts of lattice oxygen, leading to higher activity. Additionally, apparent activation energy of 68kJ/mol is calculated using Mars-van Krevelen model for C7H8 oxidation with La2CoMnO6 as catalyst. For durability test, both La2CoMnO6 and La2CuMnO6 maintain high C7H8 removal efficiencies of 100% and 98%, respectively, at 300°C and 30,000hr-1, and they also show good resistance to CO2 (5%) and H2O(g) (5%) of the gas streams tested. For various VOCs including isopropyl alcohol (C3H8O), ethanal (C2H4O), and ethylene (C2H4) tested, as high as 100% efficiency could be achieved with double perovskite-type catalysts operated at 300-350°C, indicating that double perovskites are promising catalysts for VOCs removal.
    Matched MeSH terms: Calcium Compounds/chemistry*
  8. Rice husk ash sorbent doped with copper for simultaneous removal of SO2 and NO: optimization study
    Lau LC, Lee KT, Mohamed AR
    J Hazard Mater, 2010 Nov 15;183(1-3):738-45.
    PMID: 20724075 DOI: 10.1016/j.jhazmat.2010.07.088
    In order to reduce the negative impact of coal utilization for energy generation, the pollutants present in the flue gas of coal combustion such as sulfur dioxide (SO(2)) and nitrogen oxide (NO) must be effectively removed before releasing to the atmosphere. Thus in this study, sorbent prepared from rice husk ash that is impregnated with copper is tested for simultaneous removal of SO(2) and NO from simulated flue gas. The effect of various sorbent preparation parameters; copper loading, RHA/CaO ratio, hydration period and NaOH concentration on the sorbent desulfurization/denitrification capacity was studied using Design-Expert Version 6.0.6 software. Specifically, Central Composite Design (CCD) coupled with Response Surface Method (RSM) was used. Significant individual parameters that affect the sorbent capacity are copper loading and NaOH concentration. Apart from that, interaction between the following parameters was also found to have significant effect; copper loading, RHA/CaO ratio and NaOH concentration. The optimum sorbent preparation condition for this study was found to be 3.06% CuO loading, RHA/CaO ratio of 1.41, 8.05 h of hydration period and NaOH concentration of 0.80 M. Sorbent characterization using SEM, XRD and surface area analysis were used to describe the effect of sorbent preparation parameters on the desulfurization/denitrification activity.
    Matched MeSH terms: Calcium Compounds
  9. Role of calcium oxide in sludge granulation and methanogenesis for the treatment of palm oil mill effluent using UASB reactor
    Ahmad A, Ghufran R, Abd Wahid Z
    J Hazard Mater, 2011 Dec 30;198:40-8.
    PMID: 22047724 DOI: 10.1016/j.jhazmat.2011.10.008
    The granulation process in palm oil mill effluent using calcium oxide-cement kiln dust (CaO-CKD) provides an attractive and cost effective treatment option. In this study the efficiency of CaO-CKD at doses of 1.5-20 g/l was tested in batch experiments and found that 10 g of CaO/l caused the greatest degradation of VFA, butyrate and acetate. An upflow anaerobic sludge blanket (UASB) reactor was operated continuously at 35°C for 150 days to investigate the effect of CaO-CKD on sludge granulation and methanogenesis during start-up. The treatment of POME emphasized the influence of varying organic loading rates (OLR). Up to 94.9% of COD was removed when the reactor was fed with the 15.5-65.5 g-CODg/l at an OLR of 4.5-12.5 kg-COD/m(3)d, suggesting the feasibility of using CaO in an UASB process to treat POME. The ratio of volatile solids/total solids (VS/TS) and volatile fatty acids in the anaerobic sludge in the UASB reactor decreased significantly after long-term operation due to the precipitation of calcium carbonate in the granules. Granulation and methanogenesis decreased with an increase in the influent CaO-CKD concentration.
    Matched MeSH terms: Calcium Compounds/chemistry*
  10. Fulltext STUDY ON AQUEOUS KAFFIR LIME EXTRACT AS TREATMENT AGENT ON FRESH TOMATO FRUITS
    NUR FAZLEEN SYUHADA ROSTAM, NOR AMIRA IZATI NOR AZMAN, NURUL FAZIHA IBRAHIM, SUHAIZAN LOB
    UMT Journal of Undergraduate Research, 2020;2(4):17-22.
    MyJurnal
    Tomatoes have a short shelf life thus they pose a big challenge for growers to maintain the quality of tomatoes to increase customer acceptance. In this study, fungi associated with tomato disease symptoms were isolated and the potential of kaffir lime aqueous extract was evaluated in maintaining post-harvest quality of tomatoes. For this purpose, healthy tomatoes were dipped in 10% aqueous kaffir lime extract before evaluating the post-harvest parameters namely weight loss and firmness. A fungus namely Rhizophus stolonifer was isolated from the symptomatic tomatoes. Subsequently, it was confirmed to be pathogenic on healthy tomato fruits with 100% disease severity. Application of aqueous kaffir lime extract showed that tomato fruits dipped in 10% aqueous kaffir lime extract recorded higher weight loss and higher firmness as compared to untreated tomato fruits. The results showed that treatment with this concentration of plant extract did not help to reduce the weight loss, but it retained the firmness of the tomato fruits stored at room temperature at 27+2oC. Higher transpiration process would lead to shrinkage, weight loss, changes in texture and appearance of the fruits. Therefore, this study suggested an increased concentration of aqueous kaffir lime extract as a treatment agent in order to have a better effect in maintaining the quality of tomato fruits.
    Matched MeSH terms: Calcium Compounds
  11. Fulltext Safety assessment of a new developed fruit juice product - mixed fruit Juice in experimental rats
    Hadijah, H., Norazlanshah, H., Muhammad, I., Roowi, S.
    International Food Research Journal, 2015;22(6):2657-2663.
    MyJurnal
    The interest in dietary antioxidants which are mainly found in fruits, has prompted research in
    the field of commercial high antioxidant juice for healthy purposes. Fruits also are rich with antioxidants that help in reducing of degenerative diseases such as cancer, arthritis, cardiovascular
    disease and inflammation. Based on the health claims from the natural antioxidants, a new healthy juice called Mixed Fruit Juice (MFJ) has been developed by using three combinations of local fruits (soursop, mango and kasturi lime). In order to promote the commercial use of this product, the safety evaluation is needed to be carried out. The 28-days repeated toxicity test has been conducted in female and male rats for pre-clinical safety assessment prior to human study. There was no mortality observed when varying doses of the MFJ (5, 10 and 20%) administered to all rats. Hematological analysis showed no significant differences in most parameters examined. There were no significant changes observed in the liver and kidney functions tests of all treated-rats as compared to control normal rats. Furthermore, lipid profiles and blood glucose level were also within the normal range as noted in control rats. The present data demonstrate that the supplementation of MFJ did not produce adverse effects on the body system of experimental rats. This is the first documented report on the safety assessment of
    MFJ in rats.
    Matched MeSH terms: Calcium Compounds
  12. Selection of metal oxides in the preparation of rice husk ash (RHA)/CaO sorbent for simultaneous SO2 and NO removal
    Dahlan I, Lee KT, Kamaruddin AH, Mohamed AR
    J Hazard Mater, 2009 Jul 30;166(2-3):1556-9.
    PMID: 19147280 DOI: 10.1016/j.jhazmat.2008.12.028
    In this work, the removal of SO(2) and NO from simulated flue gas from combustion process was investigated in a fixed-bed reactor using rice husk ash (RHA)/CaO-based sorbent. Various metal precursors were used in order to select the best metal impregnated over RHA/CaO sorbents. The results showed that RHA/CaO sorbents impregnated with CeO(2) had the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO(2) and NO. Infrared spectroscopic results indicated the formation of both sulfate (SO(4)(2-)) and nitrate (NO(3)(-)) species due to the catalytic role played by CeO(2). Apart from that, the catalytic activity of the RHA/CaO/CeO(2) sorbent was found to be closely related to its physical properties (specific surface area, total pore volume and average pore diameter).
    Matched MeSH terms: Calcium Compounds/chemistry*
  13. Self-assembly of a robust hydrogen-bonded octylphosphonate network on cesium lead bromide perovskite nanocrystals for light-emitting diodes
    Brown AAM, Hooper TJN, Veldhuis SA, Chin XY, Bruno A, Vashishtha P, et al.
    Nanoscale, 2019 Jul 07;11(25):12370-12380.
    PMID: 31215940 DOI: 10.1039/c9nr02566a
    We report the self-assembly of an extensive inter-ligand hydrogen-bonding network of octylphosphonates on the surface of cesium lead bromide nanocrystals (CsPbBr3 NCs). The post-synthetic addition of octylphosphonic acid to oleic acid/oleylamine-capped CsPbBr3 NCs promoted the attachment of octylphosphonate to the NC surface, while the remaining oleylammonium ligands maintained the high dispersability of the NCs in non-polar solvent. Through powerful 2D solid-state 31P-1H NMR, we demonstrated that an ethyl acetate/acetonitrile purification regime was crucial for initiating the self-assembly of extensive octylphosphonate chains. Octylphosphonate ligands were found to preferentially bind in a monodentate mode through P-O-, leaving polar P[double bond, length as m-dash]O and P-OH groups free to form inter-ligand hydrogen bonds. The octylphosphonate ligand network strongly passivated the nanocrystal surface, yielding a fully-purified CsPbBr3 NC ink with PLQY of 62%, over 3 times higher than untreated NCs. We translated this to LED devices, achieving maximum external quantum efficiency and luminance of 7.74% and 1022 cd m-2 with OPA treatment, as opposed to 3.59% and 229 cd m-2 for untreated CsPbBr3 NCs. This represents one of the highest efficiency LEDs obtained for all-inorganic CsPbBr3 NCs, accomplished through simple, effective passivation and purification processes. The robust binding of octylphosphonates to the perovskite lattice, and specifically their ability to interlink through hydrogen bonding, offers a promising passivation approach which could potentially be beneficial across a breadth of halide perovskite optoelectronic applications.
    Matched MeSH terms: Calcium Compounds
  14. Fulltext SrCo1-xTixO3-δ perovskites as excellent catalysts for fast degradation of water contaminants in neutral and alkaline solutions
    Miao J, Sunarso J, Su C, Zhou W, Wang S, Shao Z
    Sci Rep, 2017 03 10;7:44215.
    PMID: 28281656 DOI: 10.1038/srep44215
    Perovskite-like oxides SrCo1-xTixO3-δ (SCTx, x = 0.1, 0.2, 0.4, 0.6) were used as heterogeneous catalysts to activate peroxymonosulfate (PMS) for phenol degradation under a wide pH range, exhibiting more rapid phenol oxidation than Co3O4 and TiO2. The SCT0.4/PMS system produced a high activity at increased initial pH, achieving optimized performance at pH ≥ 7 in terms of total organic carbon removal, the minimum Co leaching and good catalytic stability. Kinetic studies showed that the phenol oxidation kinetics on SCT0.4/PMS system followed the pseudo-zero order kinetics and the rate on SCT0.4/PMS system decreased with increasing initial phenol concentration, decreased PMS amount, catalyst loading and solution temperature. Quenching tests using ethanol and tert-butyl alcohol demonstrated sulfate and hydroxyl radicals for phenol oxidation. This investigation suggested promising heterogeneous catalysts for organic oxidation with PMS, showing a breakthrough in the barriers of metal leaching, acidic pH, and low efficiency of heterogeneous catalysis.
    Matched MeSH terms: Calcium Compounds
  15. 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
  16. Sustained-release alginate-chitosan pellets prepared by melt pelletization technique
    Wong TW, Nurulaini H
    Drug Dev Ind Pharm, 2012 Dec;38(12):1417-27.
    PMID: 22309449 DOI: 10.3109/03639045.2011.653364
    Alginate-chitosan pellets prepared by extrusion-spheronization technique exhibited fast drug dissolution.
    Matched MeSH terms: Calcium Compounds/chemistry
  17. Synthesis and catalytic properties of calcium oxide obtained from organic ash over a titanium nanocatalyst for biodiesel production from dairy scum
    Nabgan W, Nabgan B, Ikram M, Jadhav AH, Ali MW, Ul-Hamid A, et al.
    Chemosphere, 2022 Mar;290:133296.
    PMID: 34914962 DOI: 10.1016/j.chemosphere.2021.133296
    The fatty acid methyl ester (FAME) production from dairy effluent scum as a sustainable energy source using CaO obtained from organic ash over titanium dioxide nanoparticles (TNPs) as the transesterification nano-catalyst has been studied. The physical and chemical properties of the synthesized catalysts were characterized, and the effect of different experimental factors on the biodiesel yield was studied. It was revealed that the CaO-TiO2 nano-catalyst displayed bifunctional properties, has both basic and acid phases, and leads to various effects on the catalyst activity in the transesterification process. These bifunctional properties are critical for achieving simultaneous transesterification of dairy scum oil feedstock. According to the reaction results, the catalyst without and with a low ratio of TNPs showed a low catalytic activity. In contrast, the 3Ca-3Ti nano-catalyst had the highest catalytic activity and a strong potential for reusability, producing a maximum biodiesel yield of 97.2% for a 3 wt% catalyst, 1:20 oil to methanol molar ratio for the dairy scum, and a reaction temperature of 70 °C for a period of 120 min under a 300 kPa pressure. The physical properties of the produced biodiesel are within the EN14214 standards.
    Matched MeSH terms: Calcium Compounds
  18. Fulltext Synthesis and characterization of β-tricalcium phosphate ceramic via sol-gel method
    Mohd Al Amin Muhamad Nor, Maryam Mohd Ridzuan, Zainal Arifin Ahmad
    Journal of Nuclear and Related Technologies, 2009;2009(1):199-205.
    MyJurnal
    Ceramic materials play key role in several biomedical applications. One of them is bone graft which is use in treating bone defect which caused by injury or osteoporosis. Calcium phosphates based ceramic are preferred as bone grafts in hard tissue engineering because of their chemical compositions are similar to the composition of human bone, superior bioresorbable and bioactivity. In this study, β-tricalcium phosphate (β-TCP) ceramic was synthesized by using sol-gel method. Phosphorous pentoxide (P2O5) and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) were used as calcium and phosphate precursors. The effects of calcination temperature on the synthesis powder were studied using the XRD, SEM-EDS and FTIR techniques. It was found that calcination temperature greatly influence the purity of the synthesized powders. The β-TCP was the dominant phase with the formation of α-TCP at calcination temperature from 600 to 800°C. Pure β-TCP was obtained at calcination of 900°C. As the temperature increased to 1000°C, the β-TCP was decomposed to for calcium phosphate oxide (CPO). The sol-gel method has some advantages over other methods, mainly its simplicity and ability to produce pure β-TCP at lower calcination temperature.
    Matched MeSH terms: Calcium Compounds
  19. Synthesis, mechanical properties, and in vitro biocompatibility with osteoblasts of calcium silicate-reduced graphene oxide composites
    Mehrali M, Moghaddam E, Shirazi SF, Baradaran S, Mehrali M, Latibari ST, et al.
    ACS Appl Mater Interfaces, 2014 Mar 26;6(6):3947-62.
    PMID: 24588873 DOI: 10.1021/am500845x
    Calcium silicate (CaSiO3, CS) ceramics are promising bioactive materials for bone tissue engineering, particularly for bone repair. However, the low toughness of CS limits its application in load-bearing conditions. Recent findings indicating the promising biocompatibility of graphene imply that graphene can be used as an additive to improve the mechanical properties of composites. Here, we report a simple method for the synthesis of calcium silicate/reduced graphene oxide (CS/rGO) composites using a hydrothermal approach followed by hot isostatic pressing (HIP). Adding rGO to pure CS increased the hardness of the material by ∼40%, the elastic modulus by ∼52%, and the fracture toughness by ∼123%. Different toughening mechanisms were observed including crack bridging, crack branching, crack deflection, and rGO pull-out, thus increasing the resistance to crack propagation and leading to a considerable improvement in the fracture toughness of the composites. The formation of bone-like apatite on a range of CS/rGO composites with rGO weight percentages ranging from 0 to 1.5 has been investigated in simulated body fluid (SBF). The presence of a bone-like apatite layer on the composite surface after soaking in SBF was demonstrated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The biocompatibility of the CS/rGO composites was characterized using methyl thiazole tetrazolium (MTT) assays in vitro. The cell adhesion results showed that human osteoblast cells (hFOB) can adhere to and develop on the CS/rGO composites. In addition, the proliferation rate and alkaline phosphatase (ALP) activity of cells on the CS/rGO composites were improved compared with the pure CS ceramics. These results suggest that calcium silicate/reduced graphene oxide composites are promising materials for biomedical applications.
    Matched MeSH terms: Calcium Compounds/chemistry*
  20. The Malaysian Clinical Guidance on the management of postmenopausal osteoporosis, 2012: a summary
    Yeap SS, Hew FL, Lee JK, Goh EM, Chee W, Mumtaz M, et al.
    Int J Rheum Dis, 2013 Feb;16(1):30-40.
    PMID: 23441770 DOI: 10.1111/1756-185x.12037
    AIM: This Clinical Guidance is aimed to help practitioners assess, diagnose and manage their patients with osteoporosis (OP), using the best available evidence.
    METHODS: A literature search using PubMed (MEDLINE) and The Cochrane Library identified all relevant articles on OP and its assessment, diagnosis and treatment, from 2005, to update from the previous edition published in 2006. The studies were assessed and the level of evidence assigned; for each statement, studies with the highest level of evidence were used to frame the recommendation.
    RESULTS: This article summarizes the diagnostic and treatment pathways for OP, highlighting the new data that have changed the way we assess and treat OP. Instead of starting treatment based on bone mineral density alone, there has been a move to assessing 10-year fracture risk before treatment, using tools such as the Fracture Risk Assessment Tool (FRAX). There has been a re-evaluation on calcium supplementation and more emphasis on the importance of vitamin D. There has been concern about the potential adverse effects of the long-term usage of bisphosphonates, which we have discussed fully. New drugs that have been licensed since 2006 in Malaysia have been included.
    CONCLUSIONS: Adequate intake of calcium (1000 mg from both diet and supplements) and vitamin D (800 IU) daily remain important in the treatment of OP. However, in confirmed OP, pharmacological therapy with anti-resorptives is the mainstay of treatment. Patients need to be regularly assessed while on medication and treatment adjusted as required.
    Matched MeSH terms: Calcium Compounds/administration & dosage
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