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Jing Dong - One of the best experts on this subject based on the ideXlab platform.

  • chromatographic assessment of two hybrid monoliths prepared via epoxy amine ring opening polymerization and Methacrylate based free radical polymerization using Methacrylate epoxy cyclosiloxane as functional monomer
    Journal of Chromatography A, 2014
    Co-Authors: Junjie Ou, Guang Huang, Hongwei Wang, Jing Dong
    Abstract:

    Two kinds of hybrid monolithic columns were prepared by using Methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one Methacrylate Group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65 degrees C for 12h. The other was prepared by free radical polymerization of epoxy-MA and ethylene diMethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60 degrees C for 12h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA-DAD monolith possessed higher column efficiencies (25,000-34,000 plates/m) for the separation of alkylbenzenes than the epoxy-MA-EDMA monolith (12,000-13,000 plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or Methacrylate Groups on the surface of two pristine monoliths, the epoxy-MA-EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA-DAD monolith could be modified with stearyl Methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA-DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA-DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA-EDMA monolith when compared with that on pristine epoxy-MA-EDMA monolith. The enhancement of the column efficiency of epoxy-MA-DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC. (C) 2014 Elsevier B.V. All rights reserved.

  • chromatographic assessment of two hybrid monoliths prepared via epoxy amine ring opening polymerization and Methacrylate based free radical polymerization using Methacrylate epoxy cyclosiloxane as functional monomer
    Journal of Chromatography A, 2014
    Co-Authors: Junjie Ou, Guang Huang, Hongwei Wang, Jing Dong
    Abstract:

    Abstract Two kinds of hybrid monolithic columns were prepared by using Methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one Methacrylate Group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65 °C for 12 h. The other was prepared by free radical polymerization of epoxy-MA and ethylene diMethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60 °C for 12 h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA–DAD monolith possessed higher column efficiencies (25,000–34,000 plates/m) for the separation of alkylbenzenes than the epoxy-MA–EDMA monolith (12,000–13,000 plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or Methacrylate Groups on the surface of two pristine monoliths, the epoxy-MA–EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA–DAD monolith could be modified with stearyl Methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA–DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA–DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA–EDMA monolith when compared with that on pristine epoxy-MA–EDMA monolith. The enhancement of the column efficiency of epoxy-MA–DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC.

  • polyhedral oligomeric silsesquioxanes as functional monomer to prepare hybrid monolithic columns for capillary electrochromatography and capillary liquid chromatography
    Analytica Chimica Acta, 2013
    Co-Authors: Junjie Ou, Zhenbin Zhang, Jing Dong
    Abstract:

    A simple approach to fabricate hybrid monolithic column within the confines of fused-silica capillaries (75 mu m i.d.) was introduced. A polyhedral oligomeric silsesquioxanes (POSS) reagent containing a Methacrylate Group was selected as functional monomer, and copolymerized with bisphenol A diMethacrylate (BPADMA) or ethylene diMethacrylate (EDMA) in the presence of porogenic solvents via thermally initiated free radical polymerization. After optimization of the preparation conditions, two POSS-containing hybrid monoliths were successfully prepared and exhibited good permeability and stability. By comparison of the separation efficiencies of the resulting poly(POSS-co-BPADMA) and poly(POSS-co-EDMA) monoliths in capillary electrochromatography (CEC) and capillary liquid chromatography (cLC), it was indicated the former has better column efficiencies for alkylbenzenes, phenols, anilines and PAHs in CEC and cLC than the latter. Particularly, the hybrid poly(POSS-co-BPADMA) monolith is more suitable for separation of PAHs due to pi-pi interaction between the analytes and aromatic rings in the surface of monolithic stationary phase. (C) 2012 Elsevier B.V. All rights reserved.

  • polyhedral oligomeric silsesquioxanes as functional monomer to prepare hybrid monolithic columns for capillary electrochromatography and capillary liquid chromatography
    Analytica Chimica Acta, 2013
    Co-Authors: Junjie Ou, Zhenbin Zhang, Jing Dong
    Abstract:

    A simple approach to fabricate hybrid monolithic column within the confines of fused-silica capillaries (75 mu m i.d.) was introduced. A polyhedral oligomeric silsesquioxanes (POSS) reagent containing a Methacrylate Group was selected as functional monomer, and copolymerized with bisphenol A diMethacrylate (BPADMA) or ethylene diMethacrylate (EDMA) in the presence of porogenic solvents via thermally initiated free radical polymerization. After optimization of the preparation conditions, two POSS-containing hybrid monoliths were successfully prepared and exhibited good permeability and stability. By comparison of the separation efficiencies of the resulting poly(POSS-co-BPADMA) and poly(POSS-co-EDMA) monoliths in capillary electrochromatography (CEC) and capillary liquid chromatography (cLC), it was indicated the former has better column efficiencies for alkylbenzenes, phenols, anilines and PAHs in CEC and cLC than the latter. Particularly, the hybrid poly(POSS-co-BPADMA) monolith is more suitable for separation of PAHs due to pi-pi interaction between the analytes and aromatic rings in the surface of monolithic stationary phase. (C) 2012 Elsevier B.V. All rights reserved.

Hongwei Wang - One of the best experts on this subject based on the ideXlab platform.

  • chromatographic assessment of two hybrid monoliths prepared via epoxy amine ring opening polymerization and Methacrylate based free radical polymerization using Methacrylate epoxy cyclosiloxane as functional monomer
    Journal of Chromatography A, 2014
    Co-Authors: Junjie Ou, Guang Huang, Hongwei Wang, Jing Dong
    Abstract:

    Abstract Two kinds of hybrid monolithic columns were prepared by using Methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one Methacrylate Group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65 °C for 12 h. The other was prepared by free radical polymerization of epoxy-MA and ethylene diMethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60 °C for 12 h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA–DAD monolith possessed higher column efficiencies (25,000–34,000 plates/m) for the separation of alkylbenzenes than the epoxy-MA–EDMA monolith (12,000–13,000 plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or Methacrylate Groups on the surface of two pristine monoliths, the epoxy-MA–EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA–DAD monolith could be modified with stearyl Methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA–DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA–DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA–EDMA monolith when compared with that on pristine epoxy-MA–EDMA monolith. The enhancement of the column efficiency of epoxy-MA–DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC.

  • chromatographic assessment of two hybrid monoliths prepared via epoxy amine ring opening polymerization and Methacrylate based free radical polymerization using Methacrylate epoxy cyclosiloxane as functional monomer
    Journal of Chromatography A, 2014
    Co-Authors: Junjie Ou, Guang Huang, Hongwei Wang, Jing Dong
    Abstract:

    Two kinds of hybrid monolithic columns were prepared by using Methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one Methacrylate Group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65 degrees C for 12h. The other was prepared by free radical polymerization of epoxy-MA and ethylene diMethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60 degrees C for 12h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA-DAD monolith possessed higher column efficiencies (25,000-34,000 plates/m) for the separation of alkylbenzenes than the epoxy-MA-EDMA monolith (12,000-13,000 plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or Methacrylate Groups on the surface of two pristine monoliths, the epoxy-MA-EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA-DAD monolith could be modified with stearyl Methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA-DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA-DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA-EDMA monolith when compared with that on pristine epoxy-MA-EDMA monolith. The enhancement of the column efficiency of epoxy-MA-DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC. (C) 2014 Elsevier B.V. All rights reserved.

Junjie Ou - One of the best experts on this subject based on the ideXlab platform.

  • chromatographic assessment of two hybrid monoliths prepared via epoxy amine ring opening polymerization and Methacrylate based free radical polymerization using Methacrylate epoxy cyclosiloxane as functional monomer
    Journal of Chromatography A, 2014
    Co-Authors: Junjie Ou, Guang Huang, Hongwei Wang, Jing Dong
    Abstract:

    Two kinds of hybrid monolithic columns were prepared by using Methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one Methacrylate Group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65 degrees C for 12h. The other was prepared by free radical polymerization of epoxy-MA and ethylene diMethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60 degrees C for 12h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA-DAD monolith possessed higher column efficiencies (25,000-34,000 plates/m) for the separation of alkylbenzenes than the epoxy-MA-EDMA monolith (12,000-13,000 plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or Methacrylate Groups on the surface of two pristine monoliths, the epoxy-MA-EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA-DAD monolith could be modified with stearyl Methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA-DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA-DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA-EDMA monolith when compared with that on pristine epoxy-MA-EDMA monolith. The enhancement of the column efficiency of epoxy-MA-DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC. (C) 2014 Elsevier B.V. All rights reserved.

  • chromatographic assessment of two hybrid monoliths prepared via epoxy amine ring opening polymerization and Methacrylate based free radical polymerization using Methacrylate epoxy cyclosiloxane as functional monomer
    Journal of Chromatography A, 2014
    Co-Authors: Junjie Ou, Guang Huang, Hongwei Wang, Jing Dong
    Abstract:

    Abstract Two kinds of hybrid monolithic columns were prepared by using Methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one Methacrylate Group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65 °C for 12 h. The other was prepared by free radical polymerization of epoxy-MA and ethylene diMethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60 °C for 12 h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA–DAD monolith possessed higher column efficiencies (25,000–34,000 plates/m) for the separation of alkylbenzenes than the epoxy-MA–EDMA monolith (12,000–13,000 plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or Methacrylate Groups on the surface of two pristine monoliths, the epoxy-MA–EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA–DAD monolith could be modified with stearyl Methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA–DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA–DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA–EDMA monolith when compared with that on pristine epoxy-MA–EDMA monolith. The enhancement of the column efficiency of epoxy-MA–DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC.

  • polyhedral oligomeric silsesquioxanes as functional monomer to prepare hybrid monolithic columns for capillary electrochromatography and capillary liquid chromatography
    Analytica Chimica Acta, 2013
    Co-Authors: Junjie Ou, Zhenbin Zhang, Jing Dong
    Abstract:

    A simple approach to fabricate hybrid monolithic column within the confines of fused-silica capillaries (75 mu m i.d.) was introduced. A polyhedral oligomeric silsesquioxanes (POSS) reagent containing a Methacrylate Group was selected as functional monomer, and copolymerized with bisphenol A diMethacrylate (BPADMA) or ethylene diMethacrylate (EDMA) in the presence of porogenic solvents via thermally initiated free radical polymerization. After optimization of the preparation conditions, two POSS-containing hybrid monoliths were successfully prepared and exhibited good permeability and stability. By comparison of the separation efficiencies of the resulting poly(POSS-co-BPADMA) and poly(POSS-co-EDMA) monoliths in capillary electrochromatography (CEC) and capillary liquid chromatography (cLC), it was indicated the former has better column efficiencies for alkylbenzenes, phenols, anilines and PAHs in CEC and cLC than the latter. Particularly, the hybrid poly(POSS-co-BPADMA) monolith is more suitable for separation of PAHs due to pi-pi interaction between the analytes and aromatic rings in the surface of monolithic stationary phase. (C) 2012 Elsevier B.V. All rights reserved.

  • polyhedral oligomeric silsesquioxanes as functional monomer to prepare hybrid monolithic columns for capillary electrochromatography and capillary liquid chromatography
    Analytica Chimica Acta, 2013
    Co-Authors: Junjie Ou, Zhenbin Zhang, Jing Dong
    Abstract:

    A simple approach to fabricate hybrid monolithic column within the confines of fused-silica capillaries (75 mu m i.d.) was introduced. A polyhedral oligomeric silsesquioxanes (POSS) reagent containing a Methacrylate Group was selected as functional monomer, and copolymerized with bisphenol A diMethacrylate (BPADMA) or ethylene diMethacrylate (EDMA) in the presence of porogenic solvents via thermally initiated free radical polymerization. After optimization of the preparation conditions, two POSS-containing hybrid monoliths were successfully prepared and exhibited good permeability and stability. By comparison of the separation efficiencies of the resulting poly(POSS-co-BPADMA) and poly(POSS-co-EDMA) monoliths in capillary electrochromatography (CEC) and capillary liquid chromatography (cLC), it was indicated the former has better column efficiencies for alkylbenzenes, phenols, anilines and PAHs in CEC and cLC than the latter. Particularly, the hybrid poly(POSS-co-BPADMA) monolith is more suitable for separation of PAHs due to pi-pi interaction between the analytes and aromatic rings in the surface of monolithic stationary phase. (C) 2012 Elsevier B.V. All rights reserved.

G. B. J. Andersson - One of the best experts on this subject based on the ideXlab platform.

  • augmentation of pedicle screw fixation strength using an injectable calcium phosphate cement as a function of injection timing and method
    Spine, 2004
    Co-Authors: Susan M Renner, Leonid Katolik, Howard S An, G. B. J. Andersson
    Abstract:

    STUDY DESIGN: Axial pullout tests using fresh cadaveric thoracolumbar vertebral bodies. OBJECTIVES: To evaluate the effect of a new injectable calcium phosphate cement on the axial pullout strength of both revised and augmented pedicle screws in comparison with polymethyl Methacrylate and in terms of injection method. SUMMARY OF BACKGROUND DATA: Failure of pedicle screws by loosening and back out remains a significant clinical problem and is of particular concern for patients with low bone quality. Polymethyl Methacrylate was shown to significantly improve the screw pullout strength. However, polymethyl Methacrylate is known to have a high polymerization temperature, which may damage surrounding tissues, and a short handling time, and it lacks long-term biocompatibility. Bone mineral cements such as calcium phosphate have a longer working time, very low thermal effect, and are biodegradable as well as having good mechanical strength. Recently, new calcium phosphate cement with improved infiltration properties for better injectability has been introduced, but its performance in augmenting the pedicle screw fixation has not been tested yet. METHODS: The bone mineral densities of 52 vertebral bodies (T11-L5) were measured using dual-energy x-ray absorptiometry. In each vertebral body, a 6.5-mm-diameter and 45 +/- 5-mm-long pedicle screw was inserted into either the right or left pedicle, representing an initial intact implantation. These intact screws were pulled axially until failure at 10 mm/min. Following failure of the intact pedicle, 3.0 cc of cement was injected into the failed screw hole, representing a revision case, and the prepared screw hole in the contralateral intact pedicle representing an augmentation case. The cement was injected either to the distal tip of the screw hole (calcium phosphate-1 Group, n = 19) or along the entire length of the screw hole (calcium phosphate-2 Group, n = 20), and the screws were inserted. The cement was then allowed to cure for 24 hours at room temperature before both screws were pulled to failure. In 13 specimens, polymethyl Methacrylate was injected along the entire length of the screw hole (polymethyl Methacrylate Group). Kruskal-Wallis and Mann-Whitney tests were used to compare the screw pullout strengths for study Groups, whereas linear relationships between variables were assessed with scatter plots and Spearman correlation coefficients with a significance level of 0.05. RESULTS: Mean bone mineral densities of all Groups were similar. A significant positive correlation was seen between bone mineral density and intact pullout strength. In revision, the pullout strength of calcium phosphate-1 was similar to that of intact, whereas the pullout strength of calcium phosphate-2 and polymethyl Methacrylate was significantly greater than that of intact. In augmentation, all 3 injection methods significantly improved the pullout strength over intact. Injection of the calcium phosphate cement along the entire screw length was found to produce significantly higher pullout strengths than injection only at the distal tip of the screw in revision case. Injection of polymethyl Methacrylate produced significantly higher pullout strengths than the injection of calcium phosphate by either method in both revision and augmentation. CONCLUSION: Results of this study demonstrate that the new calcium phosphate cement can improve the axial pullout strength of revised and augmented pedicle screws when injected along the entire length of the screw. This suggests that the injection method may be crucial for revision of failed pedicle screws. Considering inherent properties more favorable for in vivo application, such as nonexothermal polymerization and longer working time, and significant improvement in pullout strength, the new calcium phosphate cement may be a good alternative to polymethyl Methacrylate for the augmentation of pedicle screw fixation.

  • augmentation of pedicle screw fixation strength using an injectable calcium phosphate cement as a function of injection timing and method
    Spine, 2004
    Co-Authors: Susan M Renner, Leonid Katolik, Howard S An, G. B. J. Andersson
    Abstract:

    STUDY DESIGN: Axial pullout tests using fresh cadaveric thoracolumbar vertebral bodies. OBJECTIVES: To evaluate the effect of a new injectable calcium phosphate cement on the axial pullout strength of both revised and augmented pedicle screws in comparison with polymethyl Methacrylate and in terms of injection method. SUMMARY OF BACKGROUND DATA: Failure of pedicle screws by loosening and back out remains a significant clinical problem and is of particular concern for patients with low bone quality. Polymethyl Methacrylate was shown to significantly improve the screw pullout strength. However, polymethyl Methacrylate is known to have a high polymerization temperature, which may damage surrounding tissues, and a short handling time, and it lacks long-term biocompatibility. Bone mineral cements such as calcium phosphate have a longer working time, very low thermal effect, and are biodegradable as well as having good mechanical strength. Recently, new calcium phosphate cement with improved infiltration properties for better injectability has been introduced, but its performance in augmenting the pedicle screw fixation has not been tested yet. METHODS: The bone mineral densities of 52 vertebral bodies (T11-L5) were measured using dual-energy x-ray absorptiometry. In each vertebral body, a 6.5-mm-diameter and 45 +/- 5-mm-long pedicle screw was inserted into either the right or left pedicle, representing an initial intact implantation. These intact screws were pulled axially until failure at 10 mm/min. Following failure of the intact pedicle, 3.0 cc of cement was injected into the failed screw hole, representing a revision case, and the prepared screw hole in the contralateral intact pedicle representing an augmentation case. The cement was injected either to the distal tip of the screw hole (calcium phosphate-1 Group, n = 19) or along the entire length of the screw hole (calcium phosphate-2 Group, n = 20), and the screws were inserted. The cement was then allowed to cure for 24 hours at room temperature before both screws were pulled to failure. In 13 specimens, polymethyl Methacrylate was injected along the entire length of the screw hole (polymethyl Methacrylate Group). Kruskal-Wallis and Mann-Whitney tests were used to compare the screw pullout strengths for study Groups, whereas linear relationships between variables were assessed with scatter plots and Spearman correlation coefficients with a significance level of 0.05. RESULTS: Mean bone mineral densities of all Groups were similar. A significant positive correlation was seen between bone mineral density and intact pullout strength. In revision, the pullout strength of calcium phosphate-1 was similar to that of intact, whereas the pullout strength of calcium phosphate-2 and polymethyl Methacrylate was significantly greater than that of intact. In augmentation, all 3 injection methods significantly improved the pullout strength over intact. Injection of the calcium phosphate cement along the entire screw length was found to produce significantly higher pullout strengths than injection only at the distal tip of the screw in revision case. Injection of polymethyl Methacrylate produced significantly higher pullout strengths than the injection of calcium phosphate by either method in both revision and augmentation. CONCLUSION: Results of this study demonstrate that the new calcium phosphate cement can improve the axial pullout strength of revised and augmented pedicle screws when injected along the entire length of the screw. This suggests that the injection method may be crucial for revision of failed pedicle screws. Considering inherent properties more favorable for in vivo application, such as nonexothermal polymerization and longer working time, and significant improvement in pullout strength, the new calcium phosphate cement may be a good alternative to polymethyl Methacrylate for the augmentation of pedicle screw fixation.

Guang Huang - One of the best experts on this subject based on the ideXlab platform.

  • chromatographic assessment of two hybrid monoliths prepared via epoxy amine ring opening polymerization and Methacrylate based free radical polymerization using Methacrylate epoxy cyclosiloxane as functional monomer
    Journal of Chromatography A, 2014
    Co-Authors: Junjie Ou, Guang Huang, Hongwei Wang, Jing Dong
    Abstract:

    Abstract Two kinds of hybrid monolithic columns were prepared by using Methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one Methacrylate Group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65 °C for 12 h. The other was prepared by free radical polymerization of epoxy-MA and ethylene diMethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60 °C for 12 h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA–DAD monolith possessed higher column efficiencies (25,000–34,000 plates/m) for the separation of alkylbenzenes than the epoxy-MA–EDMA monolith (12,000–13,000 plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or Methacrylate Groups on the surface of two pristine monoliths, the epoxy-MA–EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA–DAD monolith could be modified with stearyl Methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA–DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA–DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA–EDMA monolith when compared with that on pristine epoxy-MA–EDMA monolith. The enhancement of the column efficiency of epoxy-MA–DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC.

  • chromatographic assessment of two hybrid monoliths prepared via epoxy amine ring opening polymerization and Methacrylate based free radical polymerization using Methacrylate epoxy cyclosiloxane as functional monomer
    Journal of Chromatography A, 2014
    Co-Authors: Junjie Ou, Guang Huang, Hongwei Wang, Jing Dong
    Abstract:

    Two kinds of hybrid monolithic columns were prepared by using Methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one Methacrylate Group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65 degrees C for 12h. The other was prepared by free radical polymerization of epoxy-MA and ethylene diMethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60 degrees C for 12h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA-DAD monolith possessed higher column efficiencies (25,000-34,000 plates/m) for the separation of alkylbenzenes than the epoxy-MA-EDMA monolith (12,000-13,000 plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or Methacrylate Groups on the surface of two pristine monoliths, the epoxy-MA-EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA-DAD monolith could be modified with stearyl Methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA-DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA-DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA-EDMA monolith when compared with that on pristine epoxy-MA-EDMA monolith. The enhancement of the column efficiency of epoxy-MA-DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC. (C) 2014 Elsevier B.V. All rights reserved.