The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hyd...The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hydroxyapatite of high crystallinity powder including trace Ca 10 (PO 4) 6CO 3(OH) and Ca 9HPO 4(PO 4) 6OH can be synthesized by mechanical activation without further thermal treatment at a high temperature. The synthesis reaction during the grinding process was almost completed within 1h. The as-ground powder exhibits a particle distribution of 20-100nm in size with a spherical or rodlike morphology. The composition and degree of crystallinity of the mechanochemical synthesized hydroxyapatite powders were coincident with the cement-type hydroxyapatite.展开更多
The strength development law of γ-type dicalcium silicate (γ-C_(2)S) under different carbonation processes was investigated,and the carbonation mechanism of γ-C_(2)S under the action of NH_(4)HCO_(3) was clarified ...The strength development law of γ-type dicalcium silicate (γ-C_(2)S) under different carbonation processes was investigated,and the carbonation mechanism of γ-C_(2)S under the action of NH_(4)HCO_(3) was clarified by using a wide range of test methods,including XRD and SEM.A method of saturated NH_(4)HCO_(3) solution as a curing agent was identified to improve the carbonation efficiency and enhance the carbonation degree of γ-C_(2)S,and then a high-strength carbonated specimen was obtained.Microhardness analysis and SEM morphology analysis were conducted on the carbonised specimens obtained under atmospheric pressure carbonisation conditions using the curing agent.It was found that γ-C_(2)S could perform carbonisation well under atmospheric pressure,which promoted the carbonisation efficiency and decreased the carbonisation cost simultaneously.Therefore,a new carbonisation process solution was proposed for the rapid carbonisation of γ-C_(2)S.展开更多
The mineral transition, microstructure and self-pulverization as well as the Al2O3 leaching performance of calcium aluminate clinkers with different P additions in CaO-Al2O3-SiO2 system during high-temperature sinteri...The mineral transition, microstructure and self-pulverization as well as the Al2O3 leaching performance of calcium aluminate clinkers with different P additions in CaO-Al2O3-SiO2 system during high-temperature sintering were systematically studied by XRF, XRD, SEM-EDS and DSC-TG technologies. The clinkers sintered at 1350 °C mainly contain 12CaO·7Al2O3, CaO·Al2O3,β-2CaO·SiO2 and γ-2CaO·SiO2. The content of β-2CaO·SiO2 increases while the content of γ-2CaO·SiO2 decreases as the P addition increases. The self-pulverization property of clinkers deteriorates with increasing P addition. P distributes evenly in the clinkers, and inhibits the transformation of β-2CaO·SiO2 to γ-2CaO·SiO2. The cell volumes of 12CaO·7Al2O3 and CaO·Al2O3 decrease and increase respectively as the P addition increases, and P decreases their formation temperatures. The Al2O3 leaching rate of calcium aluminate clinkers decreases obviously with increasing P addition, which decreases form 95.01% to 83.84% as the P addition increases from 0 to 0.85%.展开更多
The adsorption isotherm of sodium polyacrylate on dicalcium silicate（2CaO-SiO2） in sodium aluminate solution at 80 ℃ was studied.The type of surface adsorption of sodium polyacrylate is saturated adsorption,and the...The adsorption isotherm of sodium polyacrylate on dicalcium silicate（2CaO-SiO2） in sodium aluminate solution at 80 ℃ was studied.The type of surface adsorption of sodium polyacrylate is saturated adsorption,and the adsorption behavior belongs to L-type,according with the monolayer adsorption model of Langmuir equation.The surface coverage of sodium polyacrylate is 1.06 mol/μm2.The relation curve between the surface pressure and the molecular area of adsorption film was obtained by Gibbs formula.The variation of interfacial energy caused by adsorption as well as the relationship between the relation curve and the type of adsorption was discussed.展开更多
Low calcium β-C2S and γ-C2S minerals with low hydration activity was activated by accelerated carbonation curing to be used as new binding materials.Synthetic β-C2S and γ-C2S were synthetized and compacted to prep...Low calcium β-C2S and γ-C2S minerals with low hydration activity was activated by accelerated carbonation curing to be used as new binding materials.Synthetic β-C2S and γ-C2S were synthetized and compacted to prepare cube samples and then subjected to CO2 chamber for accelerated carbonation curing.The CO2 uptake,mechanical strength,and microstructure changes of β-C2S and γ-C2S were analyzed by TG,XRD,MAS-NMR,and MIP.The experimental results indicate the CO2 uptake of γ-C2S is much higher than that of β-C2S,but the compressive strength of γ-C2S samples is lower than that of β-C2S.Calcium carbonate and other carbonation products stack in the pore structure and the porosity is reduced from about 42% to 30.1% and 22.0% for β-C2S and γ-C2S samples after 2 h carbonation curing,respectively.The difference in compressive strength development is caused by the different properties of carbonation products.Except for calcium carbonate,there also exists obvious difference in properties of amorphous phases:γ-C2S formed silica gel in the whole carbonation progress;however,β-C2S can react to produce silica gel and C-S-H gel with high Van der Waals forces,and C-S-H gel will continue to react with CO2 to form calcium carbonate and silica gel in later carbonation reaction;In addition the microhardness of carbonated β-C2S was more higher than that of γ-C2S.展开更多
The present work presents the microstructure of β-Ca_2SiO_4(β-C_2S) after accelerated carbonation. The synthesis procedure of β-C_2S was examined first, and the crystalline and amorphous structure, the distribution...The present work presents the microstructure of β-Ca_2SiO_4(β-C_2S) after accelerated carbonation. The synthesis procedure of β-C_2S was examined first, and the crystalline and amorphous structure, the distribution and the pore structure of β-C_2S carbonation products were also determined by X-ray diffraction(XRD) quantitative analysis, simultaneous thermal analyzer(TG/DTA), Fourier transform-infrared spectroscopy(FT-IR), high resolution ^(29)Si magic angle spinning nuclear magnetic resonance(^(29)Si NMR), N_2-sorption techniques, and scanning electron microscopy(SEM), respectively. Test results indicate that carbonation products are dramatically formed in the initial 2 h. The main carbonation products are crystalline calcite and amorphous three-dimensional network silica gels, which contain nanometer-sized pores. The calcite, silica gels and un-carbonated β-C_2S are distributed hierarchically.展开更多
Rat calvarial osteoblasts were treated with lanthanum chloride（LaCl3） to explore its effect on the mineral crystalline phase during the process of osteoblast calcification in uitro.The results confirmed that La was ...Rat calvarial osteoblasts were treated with lanthanum chloride（LaCl3） to explore its effect on the mineral crystalline phase during the process of osteoblast calcification in uitro.The results confirmed that La was readily deposited in the mineral component of the matrix.Employing high-resolution transmission electron microscopy and Fourier transform infrared microspectroscopy techniques,we demonstrated that features comparable to dicalcium phosphate dihydrate（DCPD） and octacalcium phosphate,and hydroxyapatite（HAP） were detected in the mineral phases in uitro.Particularly,LaCl3 treatment retarded conversion from DCPD-like phase into HAP during mineralization.In addition,La was introduced in DCPD powder during wet chemical synthesis.When compared with that of La-free DCPD,the dissolution rate of La-incorporated DCPD was lower,thereby leading to a delayed DCPD-to-HAP phase transformation.Thus,it can be concluded that LaCl3 treatment influences the kinetics of inorganic phase transition by decreasing the dissolution rate of DCPD.展开更多
Dicalcium silicate(Ca_(2)SiO_(4),C_(2)S)has osteogenic potential but induces macrophagic inflammation.Mitochondrial function plays a vital role in macrophage polarization and macrophagic inflammation.The mitochondrial...Dicalcium silicate(Ca_(2)SiO_(4),C_(2)S)has osteogenic potential but induces macrophagic inflammation.Mitochondrial function plays a vital role in macrophage polarization and macrophagic inflammation.The mitochondrial function of C_(2)S-treated macrophages is still unclear.This study hypothesized:(i)the C_(2)S modulates mitochondrial function and autophagy in macrophages to regulate macro-phagic inflammation,and(ii)C_(2)S-induced macrophagic inflammation regulates osteogenesis.We used RAW264.7 cells as a model of macrophage.The C_(2)S(75–150μg/ml)extract was used to analyze the macrophagic mitochondrial function and macrophagemediated effect on osteogenic differentiation of mouse bone marrow-derived mesenchymal stem cells(BMSCs).The results showed that C_(2)S extract(150μg/ml)induced TNF-α,IL-1βand IL-6 production in macrophages.C_(2)S extract(150μg/ml)enhanced reactive oxygen species level and intracellular calcium level but reduced mitochondrial membrane potential and ATP production.TEM images showed reduced mitochondrial abundance and altered the mitochondrial morphology in C_(2)S(150μg/ml)-treated macrophages.Protein level expression of PINK1,Parkin,Beclin1 and LC3 was upregulated but TOMM20 was downregulated.mRNA sequencing and KEGG analysis showed that C_(2)S-induced differentially expressed mRNAs in macrophages were mainly distributed in the essential signaling pathways involved in mitochondrial function and autophagy.The conditioned medium from C_(2)S-treated macrophage robustly promoted osteogenic differentiation in BMSCs.In conclusion,our results indicate mitochondrial dysfunction and autophagy as the possible mechanism of C_(2)S-induced macrophagic inflammation.The promotion of osteogenic differentiation of BMSCs by the C_(2)S-induced macrophagic inflammation suggests the potential application of C_(2)S in developing immunomodulatory bone grafts.展开更多
The phase transition,morphology,stability and pulverization performance of dicalcium silicate(C_(2)S)with different Na_(2)O additions during the high-temperature sintering process were studied using XRD,SEM-EDS,FT-IR,...The phase transition,morphology,stability and pulverization performance of dicalcium silicate(C_(2)S)with different Na_(2)O additions during the high-temperature sintering process were studied using XRD,SEM-EDS,FT-IR,and Raman spectra methods.When the CaO to SiO_(2) molar ratio is 2.0 and the Na_(2)O to SiO_(2) molar ratio is below 0.20,the crystalline calcium silicate compounds includeγ-C_(2)S andβ-C_(2)S.As the Na_(2)O addition increases,the proportion,crystallinity and grain size ofβ-C_(2)S in the sintered products increase,those parameters ofγ-C_(2)S decrease,and the content of amorphous phase increases.Na_(2)O mainly forms solid solutions inβ-C_(2)S and inhibits the transition ofβ-C_(2)S toγ-C_(2)S,resulting in the sintered products unpulverized.The stability of sintered products in alkali solution decreases significantly with the increasing Na_(2)O additions,and theβ-C_(2)S solid solution with Na_(2)O is less stable thanγ-C_(2)S.The mechanism that Na_(2)O affects the transition of C_(2)S as well as its stability was also discussed,which can give actual guidance for the treatment of low-grade alumina-containing resources by the sintering process.展开更多
On the bases of practical investigation, the paper, through synthesizing lots of documents and materials, discusses the stability and crystalline pattern transforming of C_2S, the hydrating and hardening mechanism of ...On the bases of practical investigation, the paper, through synthesizing lots of documents and materials, discusses the stability and crystalline pattern transforming of C_2S, the hydrating and hardening mechanism of its solid solution as well as the affect of adding ions. In recent years, the research on C_2S has been attached importance to and has achieved obvious success, especially in the study of the match phase of C_2S solid solution, many cement systems with fine characteristics have been formed. It shows it's quite easy for C_2S to match other minerals, which plays an important role in saving energy, improving cement properties and developing new cement materials. The broad propspects are revealed in C_2S studying area.展开更多
<span style="font-family:Verdana;">The apparent calcium (Ca) digestibility coefficient (ADC) and true digestibility coefficient (TDC) of different inorganic calcium sources were determined in laying he...<span style="font-family:Verdana;">The apparent calcium (Ca) digestibility coefficient (ADC) and true digestibility coefficient (TDC) of different inorganic calcium sources were determined in laying hens of different ages. Three Ca digestibility tests were carried out, each assessing 240 Lohmann Brown lineage laying hens distributed in a completely randomized design. Nine dietary treatments were arranged in a 3 </span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">×</span><span style="font-family:Verdana;"> 3 factorial design consisting of three ages (40, 50 and 70 weeks) </span><span style="font-family:Verdana;">×</span><span style="font-family:Verdana;"> three Ca (dicalcium phosphate (DCP) sources,</span><span style="font-family:Verdana;"> fine (FL) and coarse (CL)) limestone, comprising eight replicates per treatment of six birds per experimental unit. Regarding the DCP, the ADC was higher (P < 0.05) in 40-week-old birds. The DCP ADC for 40-, 50- and 70-week-old birds w</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">as</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> 0.889, 0.613 and 0.712, respectively. No effect (P > 0.05) of age on the ADC was noted for either FL </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">or</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> CL. Comparing Ca sources, DCP exhibited a higher (P < 0.05) ADC (0.889), followed by FL (0.699) and CL (0.515), in 40-week-old birds. DCP (0.712) and FL (0.652) presented (P < 0.05) higher ADC compared to CL (0.482), in 70-week-old birds. No effect of Ca sources at 50 weeks on the ADC was observed (P > 0.05). Endogenous loss values of 790, 860 and 930 mg·kg<span style="color:#636363;"><span style="font-s展开更多
Using the laser granularity survey technology , logy, X-ray powder diffraction, scanning electron microscopy （SEM） and infrared spectrum anal）sis methods, we studied the microscopic structure and chemical bonds cha...Using the laser granularity survey technology , logy, X-ray powder diffraction, scanning electron microscopy （SEM） and infrared spectrum anal）sis methods, we studied the microscopic structure and chemical bonds changes of β-C2 S monomineral under the high energy ball grinding function. The result indicates that, continuously under the mechanical power, β-C2 S crystal size would decrease, the micro strain and the effective Beff parameter would increase, and the amorphous phases would be presented. Furthermore, the mechanical power would cause Si-O bond broken and reorganized, the specific surface area would increase, the energy of micro-powder agglomeration vibration would be enhanced and the crystal would be disordered. Finally, β- C2 S was caused to have the mechanochemical change and the activity enhancement.展开更多
Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition we...Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.展开更多
The transparent or opaque zein film was prepared by a phase separation method with a zein ethanol aqueous solution.The circular zein film was self-assembled on the air-water interface.According to the images by scanni...The transparent or opaque zein film was prepared by a phase separation method with a zein ethanol aqueous solution.The circular zein film was self-assembled on the air-water interface.According to the images by scanning electron microscopy,the upper surface of film is flat and smooth and the downward surface presents a complex reticulation structure of corn protein fiber.Zein film as a biomimetic mineralization template is used to synthesize calcium phosphate crystals by a bioinspired mineralization process.Randomly oriented apatite crystals appear on the both surfaces of zein film after immersion in lOxsimulated body fluid,and the phase composition and morphology of the deposited calcium apatite are also distinguished from deposited location and immersion time.The phase transformation process from dicalcium phosphate dihydrate into hydroxyapatite(HAp) phase was investigated by X-ray powder diffraction,transmission electron microscopy and Fourier transform infrared spectroscopy,respectively.Based on the results by energy dispersive X-ray spectroscopy,the Ca/P ratio of the deposited apatite increases with the transformation from DCPD to HAp.The HAp/Zein films possess the excellent biodegradable structural features,and the coating of HAp crystallites has some potential applications for bone repair and regeneration.展开更多
Next-generation synthetic bone graft therapies will most likely be composed of resorbable polymers in combination with bioactive components.In this article,we continue our exploration of E1001(1k),a tyrosine-derived p...Next-generation synthetic bone graft therapies will most likely be composed of resorbable polymers in combination with bioactive components.In this article,we continue our exploration of E1001(1k),a tyrosine-derived polycarbonate,as an orthopedic implant material.Specifically,we use E1001(1k),which is degradable,nontoxic,and osteoconductive,to fabricate porous bone regeneration scaffolds that were enhanced by two different types of calcium phosphate(CP)coatings:in one case,pure dicalcium phosphate dihydrate was precipitated on the scaffold surface and throughout its porous structure(E1001(1k)+CP).In the other case,bone matrix minerals(BMM)such as zinc,manganese and fluoride were co-precipitated within the dicalcium phosphate dihydrate coating(E1001(1k)+BMM).These scaffold compositions were compared against each other and against ChronOS(Synthes USA,West Chester,PA,USA),a clinically used bone graft substitute(BGS),which served as the positive control in our experimental design.This BGS is composed of poly(lactide co-e-caprolactone)and beta-tricalcium phosphate.We used the established rabbit calvaria critical-sized defect model to determine bone regeneration within the defect for each of the three scaffold compositions.New bone formation was determined after 2,4,6,8 and 12 weeks by micro-computerized tomography(mCT)and histology.The experimental tyrosine-derived polycarbonate,enhanced with dicalcium phosphate dihydrate,E1001(1k)+CP,supported significant bone formation within the defects and was superior to the same scaffold containing a mix of BMM,E1001(1k)+BMM.The comparison with the commercially available BGS was complicated by the large variability in bone formation observed for the laboratory preparations of E1001(1k)scaffolds.At all time points,there was a trend for E1001(1k)+CP to be superior to the commercial BGS.However,only at the 6-week time point did this trend reach statistical significance.Detailed analysis of the μCT data suggested an increase in bone formation from 2 through 12 weeks in implant site展开更多
文摘The mixture of CaHPO 4·2H 2O and CaCO 3 was ground in an aqueous system under appropriate conditions to investigate the mechanochemical reaction for the synthesis of crystalline hydroxyapatite (HA) powder. Hydroxyapatite of high crystallinity powder including trace Ca 10 (PO 4) 6CO 3(OH) and Ca 9HPO 4(PO 4) 6OH can be synthesized by mechanical activation without further thermal treatment at a high temperature. The synthesis reaction during the grinding process was almost completed within 1h. The as-ground powder exhibits a particle distribution of 20-100nm in size with a spherical or rodlike morphology. The composition and degree of crystallinity of the mechanochemical synthesized hydroxyapatite powders were coincident with the cement-type hydroxyapatite.
基金Funded by Hubei Technology Innovation Key Program (No.2018AAA004)。
文摘The strength development law of γ-type dicalcium silicate (γ-C_(2)S) under different carbonation processes was investigated,and the carbonation mechanism of γ-C_(2)S under the action of NH_(4)HCO_(3) was clarified by using a wide range of test methods,including XRD and SEM.A method of saturated NH_(4)HCO_(3) solution as a curing agent was identified to improve the carbonation efficiency and enhance the carbonation degree of γ-C_(2)S,and then a high-strength carbonated specimen was obtained.Microhardness analysis and SEM morphology analysis were conducted on the carbonised specimens obtained under atmospheric pressure carbonisation conditions using the curing agent.It was found that γ-C_(2)S could perform carbonisation well under atmospheric pressure,which promoted the carbonisation efficiency and decreased the carbonisation cost simultaneously.Therefore,a new carbonisation process solution was proposed for the rapid carbonisation of γ-C_(2)S.
基金Projects(51674075,51774079) supported by the National Natural Science Foundation of China
文摘The mineral transition, microstructure and self-pulverization as well as the Al2O3 leaching performance of calcium aluminate clinkers with different P additions in CaO-Al2O3-SiO2 system during high-temperature sintering were systematically studied by XRF, XRD, SEM-EDS and DSC-TG technologies. The clinkers sintered at 1350 °C mainly contain 12CaO·7Al2O3, CaO·Al2O3,β-2CaO·SiO2 and γ-2CaO·SiO2. The content of β-2CaO·SiO2 increases while the content of γ-2CaO·SiO2 decreases as the P addition increases. The self-pulverization property of clinkers deteriorates with increasing P addition. P distributes evenly in the clinkers, and inhibits the transformation of β-2CaO·SiO2 to γ-2CaO·SiO2. The cell volumes of 12CaO·7Al2O3 and CaO·Al2O3 decrease and increase respectively as the P addition increases, and P decreases their formation temperatures. The Al2O3 leaching rate of calcium aluminate clinkers decreases obviously with increasing P addition, which decreases form 95.01% to 83.84% as the P addition increases from 0 to 0.85%.
基金Project(50974036)supported by the National Natural Science Foundation of China
文摘The adsorption isotherm of sodium polyacrylate on dicalcium silicate（2CaO-SiO2） in sodium aluminate solution at 80 ℃ was studied.The type of surface adsorption of sodium polyacrylate is saturated adsorption,and the adsorption behavior belongs to L-type,according with the monolayer adsorption model of Langmuir equation.The surface coverage of sodium polyacrylate is 1.06 mol/μm2.The relation curve between the surface pressure and the molecular area of adsorption film was obtained by Gibbs formula.The variation of interfacial energy caused by adsorption as well as the relationship between the relation curve and the type of adsorption was discussed.
基金Funded by the National Natural Science Foundation of China(Nos.51808354,51808351 and 51808532)the National Natural Science Foundation of Liaoning,China(No.20180550127)+1 种基金the China Postdoctoral Science Foundation(No.2018M641712)the State Key Laboratory of Silicate Materials for Architectures(Wuhan University of Technology)。
文摘Low calcium β-C2S and γ-C2S minerals with low hydration activity was activated by accelerated carbonation curing to be used as new binding materials.Synthetic β-C2S and γ-C2S were synthetized and compacted to prepare cube samples and then subjected to CO2 chamber for accelerated carbonation curing.The CO2 uptake,mechanical strength,and microstructure changes of β-C2S and γ-C2S were analyzed by TG,XRD,MAS-NMR,and MIP.The experimental results indicate the CO2 uptake of γ-C2S is much higher than that of β-C2S,but the compressive strength of γ-C2S samples is lower than that of β-C2S.Calcium carbonate and other carbonation products stack in the pore structure and the porosity is reduced from about 42% to 30.1% and 22.0% for β-C2S and γ-C2S samples after 2 h carbonation curing,respectively.The difference in compressive strength development is caused by the different properties of carbonation products.Except for calcium carbonate,there also exists obvious difference in properties of amorphous phases:γ-C2S formed silica gel in the whole carbonation progress;however,β-C2S can react to produce silica gel and C-S-H gel with high Van der Waals forces,and C-S-H gel will continue to react with CO2 to form calcium carbonate and silica gel in later carbonation reaction;In addition the microhardness of carbonated β-C2S was more higher than that of γ-C2S.
基金Funded by the National Natural Science Foundation of China(Nos.51272068,U1604118,and 51502080)
文摘The present work presents the microstructure of β-Ca_2SiO_4(β-C_2S) after accelerated carbonation. The synthesis procedure of β-C_2S was examined first, and the crystalline and amorphous structure, the distribution and the pore structure of β-C_2S carbonation products were also determined by X-ray diffraction(XRD) quantitative analysis, simultaneous thermal analyzer(TG/DTA), Fourier transform-infrared spectroscopy(FT-IR), high resolution ^(29)Si magic angle spinning nuclear magnetic resonance(^(29)Si NMR), N_2-sorption techniques, and scanning electron microscopy(SEM), respectively. Test results indicate that carbonation products are dramatically formed in the initial 2 h. The main carbonation products are crystalline calcite and amorphous three-dimensional network silica gels, which contain nanometer-sized pores. The calcite, silica gels and un-carbonated β-C_2S are distributed hierarchically.
基金supported by the National Natural Science Foundation of China(No.21101008)
文摘Rat calvarial osteoblasts were treated with lanthanum chloride（LaCl3） to explore its effect on the mineral crystalline phase during the process of osteoblast calcification in uitro.The results confirmed that La was readily deposited in the mineral component of the matrix.Employing high-resolution transmission electron microscopy and Fourier transform infrared microspectroscopy techniques,we demonstrated that features comparable to dicalcium phosphate dihydrate（DCPD） and octacalcium phosphate,and hydroxyapatite（HAP） were detected in the mineral phases in uitro.Particularly,LaCl3 treatment retarded conversion from DCPD-like phase into HAP during mineralization.In addition,La was introduced in DCPD powder during wet chemical synthesis.When compared with that of La-free DCPD,the dissolution rate of La-incorporated DCPD was lower,thereby leading to a delayed DCPD-to-HAP phase transformation.Thus,it can be concluded that LaCl3 treatment influences the kinetics of inorganic phase transition by decreasing the dissolution rate of DCPD.
基金supported by High-level University Construction Funding of Guangzhou Medical University(02-412-B205002-1003017,06-410-2106035).
文摘Dicalcium silicate(Ca_(2)SiO_(4),C_(2)S)has osteogenic potential but induces macrophagic inflammation.Mitochondrial function plays a vital role in macrophage polarization and macrophagic inflammation.The mitochondrial function of C_(2)S-treated macrophages is still unclear.This study hypothesized:(i)the C_(2)S modulates mitochondrial function and autophagy in macrophages to regulate macro-phagic inflammation,and(ii)C_(2)S-induced macrophagic inflammation regulates osteogenesis.We used RAW264.7 cells as a model of macrophage.The C_(2)S(75–150μg/ml)extract was used to analyze the macrophagic mitochondrial function and macrophagemediated effect on osteogenic differentiation of mouse bone marrow-derived mesenchymal stem cells(BMSCs).The results showed that C_(2)S extract(150μg/ml)induced TNF-α,IL-1βand IL-6 production in macrophages.C_(2)S extract(150μg/ml)enhanced reactive oxygen species level and intracellular calcium level but reduced mitochondrial membrane potential and ATP production.TEM images showed reduced mitochondrial abundance and altered the mitochondrial morphology in C_(2)S(150μg/ml)-treated macrophages.Protein level expression of PINK1,Parkin,Beclin1 and LC3 was upregulated but TOMM20 was downregulated.mRNA sequencing and KEGG analysis showed that C_(2)S-induced differentially expressed mRNAs in macrophages were mainly distributed in the essential signaling pathways involved in mitochondrial function and autophagy.The conditioned medium from C_(2)S-treated macrophage robustly promoted osteogenic differentiation in BMSCs.In conclusion,our results indicate mitochondrial dysfunction and autophagy as the possible mechanism of C_(2)S-induced macrophagic inflammation.The promotion of osteogenic differentiation of BMSCs by the C_(2)S-induced macrophagic inflammation suggests the potential application of C_(2)S in developing immunomodulatory bone grafts.
基金Project(2018YFC1901903)supported by the National Key R&D Program of ChinaProjects(22078055,52074083,51674075)supported by the National Natural Science Foundation of China。
文摘The phase transition,morphology,stability and pulverization performance of dicalcium silicate(C_(2)S)with different Na_(2)O additions during the high-temperature sintering process were studied using XRD,SEM-EDS,FT-IR,and Raman spectra methods.When the CaO to SiO_(2) molar ratio is 2.0 and the Na_(2)O to SiO_(2) molar ratio is below 0.20,the crystalline calcium silicate compounds includeγ-C_(2)S andβ-C_(2)S.As the Na_(2)O addition increases,the proportion,crystallinity and grain size ofβ-C_(2)S in the sintered products increase,those parameters ofγ-C_(2)S decrease,and the content of amorphous phase increases.Na_(2)O mainly forms solid solutions inβ-C_(2)S and inhibits the transition ofβ-C_(2)S toγ-C_(2)S,resulting in the sintered products unpulverized.The stability of sintered products in alkali solution decreases significantly with the increasing Na_(2)O additions,and theβ-C_(2)S solid solution with Na_(2)O is less stable thanγ-C_(2)S.The mechanism that Na_(2)O affects the transition of C_(2)S as well as its stability was also discussed,which can give actual guidance for the treatment of low-grade alumina-containing resources by the sintering process.
文摘On the bases of practical investigation, the paper, through synthesizing lots of documents and materials, discusses the stability and crystalline pattern transforming of C_2S, the hydrating and hardening mechanism of its solid solution as well as the affect of adding ions. In recent years, the research on C_2S has been attached importance to and has achieved obvious success, especially in the study of the match phase of C_2S solid solution, many cement systems with fine characteristics have been formed. It shows it's quite easy for C_2S to match other minerals, which plays an important role in saving energy, improving cement properties and developing new cement materials. The broad propspects are revealed in C_2S studying area.
文摘<span style="font-family:Verdana;">The apparent calcium (Ca) digestibility coefficient (ADC) and true digestibility coefficient (TDC) of different inorganic calcium sources were determined in laying hens of different ages. Three Ca digestibility tests were carried out, each assessing 240 Lohmann Brown lineage laying hens distributed in a completely randomized design. Nine dietary treatments were arranged in a 3 </span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">×</span><span style="font-family:Verdana;"> 3 factorial design consisting of three ages (40, 50 and 70 weeks) </span><span style="font-family:Verdana;">×</span><span style="font-family:Verdana;"> three Ca (dicalcium phosphate (DCP) sources,</span><span style="font-family:Verdana;"> fine (FL) and coarse (CL)) limestone, comprising eight replicates per treatment of six birds per experimental unit. Regarding the DCP, the ADC was higher (P < 0.05) in 40-week-old birds. The DCP ADC for 40-, 50- and 70-week-old birds w</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">as</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> 0.889, 0.613 and 0.712, respectively. No effect (P > 0.05) of age on the ADC was noted for either FL </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">or</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> CL. Comparing Ca sources, DCP exhibited a higher (P < 0.05) ADC (0.889), followed by FL (0.699) and CL (0.515), in 40-week-old birds. DCP (0.712) and FL (0.652) presented (P < 0.05) higher ADC compared to CL (0.482), in 70-week-old birds. No effect of Ca sources at 50 weeks on the ADC was observed (P > 0.05). Endogenous loss values of 790, 860 and 930 mg·kg<span style="color:#636363;"><span style="font-s
文摘Using the laser granularity survey technology , logy, X-ray powder diffraction, scanning electron microscopy （SEM） and infrared spectrum anal）sis methods, we studied the microscopic structure and chemical bonds changes of β-C2 S monomineral under the high energy ball grinding function. The result indicates that, continuously under the mechanical power, β-C2 S crystal size would decrease, the micro strain and the effective Beff parameter would increase, and the amorphous phases would be presented. Furthermore, the mechanical power would cause Si-O bond broken and reorganized, the specific surface area would increase, the energy of micro-powder agglomeration vibration would be enhanced and the crystal would be disordered. Finally, β- C2 S was caused to have the mechanochemical change and the activity enhancement.
基金Project (2003AA302210) supported by the National High Technology Research and Development Program of Chinaproject(04JJ3083) supported by the Elite Foundation of Hunan Province+1 种基金 China project (030615) supported by the Innovation Pro
文摘Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.
基金supported by the National Natural Science Foundation of China(50972103)the Scientific Research Foundation for Returned Overseas Chinese Scholars,Ministry of Education of China
文摘The transparent or opaque zein film was prepared by a phase separation method with a zein ethanol aqueous solution.The circular zein film was self-assembled on the air-water interface.According to the images by scanning electron microscopy,the upper surface of film is flat and smooth and the downward surface presents a complex reticulation structure of corn protein fiber.Zein film as a biomimetic mineralization template is used to synthesize calcium phosphate crystals by a bioinspired mineralization process.Randomly oriented apatite crystals appear on the both surfaces of zein film after immersion in lOxsimulated body fluid,and the phase composition and morphology of the deposited calcium apatite are also distinguished from deposited location and immersion time.The phase transformation process from dicalcium phosphate dihydrate into hydroxyapatite(HAp) phase was investigated by X-ray powder diffraction,transmission electron microscopy and Fourier transform infrared spectroscopy,respectively.Based on the results by energy dispersive X-ray spectroscopy,the Ca/P ratio of the deposited apatite increases with the transformation from DCPD to HAp.The HAp/Zein films possess the excellent biodegradable structural features,and the coating of HAp crystallites has some potential applications for bone repair and regeneration.
基金This research was sponsored by the Armed Forces Institute of Regenerative Medicine(AFIRM)award number W81XWH-08-2-0034The US Army Medical Research Acquisition Activity,820 Chandler Street,Fort Detrick MD 21702-5014 is the awarding and administering acquisition office。
文摘Next-generation synthetic bone graft therapies will most likely be composed of resorbable polymers in combination with bioactive components.In this article,we continue our exploration of E1001(1k),a tyrosine-derived polycarbonate,as an orthopedic implant material.Specifically,we use E1001(1k),which is degradable,nontoxic,and osteoconductive,to fabricate porous bone regeneration scaffolds that were enhanced by two different types of calcium phosphate(CP)coatings:in one case,pure dicalcium phosphate dihydrate was precipitated on the scaffold surface and throughout its porous structure(E1001(1k)+CP).In the other case,bone matrix minerals(BMM)such as zinc,manganese and fluoride were co-precipitated within the dicalcium phosphate dihydrate coating(E1001(1k)+BMM).These scaffold compositions were compared against each other and against ChronOS(Synthes USA,West Chester,PA,USA),a clinically used bone graft substitute(BGS),which served as the positive control in our experimental design.This BGS is composed of poly(lactide co-e-caprolactone)and beta-tricalcium phosphate.We used the established rabbit calvaria critical-sized defect model to determine bone regeneration within the defect for each of the three scaffold compositions.New bone formation was determined after 2,4,6,8 and 12 weeks by micro-computerized tomography(mCT)and histology.The experimental tyrosine-derived polycarbonate,enhanced with dicalcium phosphate dihydrate,E1001(1k)+CP,supported significant bone formation within the defects and was superior to the same scaffold containing a mix of BMM,E1001(1k)+BMM.The comparison with the commercially available BGS was complicated by the large variability in bone formation observed for the laboratory preparations of E1001(1k)scaffolds.At all time points,there was a trend for E1001(1k)+CP to be superior to the commercial BGS.However,only at the 6-week time point did this trend reach statistical significance.Detailed analysis of the μCT data suggested an increase in bone formation from 2 through 12 weeks in implant site
