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M. R. A. Pillai - One of the best experts on this subject based on the ideXlab platform.
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preparation of clinical scale 99mo 99mtc Column generator using neutron activated low specific activity 99mo and nanocrystalline γ al2o3 as Column Matrix
Nuclear Medicine and Biology, 2012Co-Authors: Rubel Chakravarty, Ramu Ram, Ashutosh Dash, M. R. A. PillaiAbstract:Abstract Introduction Preparation of clinical-scale 99 Mo/ 99m Tc generator using (n,γ) activated low specific activity 99 Mo and nanocrystalline γ-Al 2 O 3 as a high capacity sorbent Matrix is attempted. Methods Nanocrystalline γ-Al 2 O 3 was synthesized by ‘solid state mechanochemical' reaction of aluminum nitrate with ammonium bicarbonate. Experimental parameters were optimized to effectively separate 99m Tc from 99 Mo using this sorbent as the Column Matrix. The performance features of a 13GBq (350mCi) 99 Mo/ 99m Tc generator using this sorbent and 99 Mo produced by (n,γ) route having specific activity 12.9–18.5GBq/g were evaluated for 10days. Results The sorbent possessed the requisite selectivity for 99 Mo and demonstrated a maximum sorption capacity of 200±5mg Mo/g, which is ~10 times higher than that of ordinary acidic alumina. The overall yield of 99m Tc was >80%, with radionuclidic purity >99.99% and radiochemical purity >99%. The yield of 99m Tc varied from 7.8 to 2.1GBq in the eluate for the six days of operation of the generator. The radioactive concentration of 99m Tc eluted was adequate for the formulation of radiopharmaceuticals. The performance of the generator remained consistent over an extended period of 10days. The eluted 99m Tc was suitable for the formulation of 99m Tc-DMSA and 99m Tc-EC resulting in high radiolabeling yields (>98%). Conclusion The effectiveness of γ-Al 2 O 3 as a new generation sorbent in the development of clinically useful 99 Mo/ 99m Tc generator using low specific activity 99 Mo and yielding 99m Tc with adequate radioactive concentration and high purity suitable for formulation of radiopharmaceuticals is demonstrated.
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Preparation of clinical-scale 99Mo/99mTc Column generator using neutron activated low specific activity 99Mo and nanocrystalline γ-Al2O3 as Column Matrix.
Nuclear Medicine and Biology, 2012Co-Authors: Rubel Chakravarty, Ramu Ram, Ashutosh Dash, M. R. A. PillaiAbstract:Abstract Introduction Preparation of clinical-scale 99 Mo/ 99m Tc generator using (n,γ) activated low specific activity 99 Mo and nanocrystalline γ-Al 2 O 3 as a high capacity sorbent Matrix is attempted. Methods Nanocrystalline γ-Al 2 O 3 was synthesized by ‘solid state mechanochemical' reaction of aluminum nitrate with ammonium bicarbonate. Experimental parameters were optimized to effectively separate 99m Tc from 99 Mo using this sorbent as the Column Matrix. The performance features of a 13GBq (350mCi) 99 Mo/ 99m Tc generator using this sorbent and 99 Mo produced by (n,γ) route having specific activity 12.9–18.5GBq/g were evaluated for 10days. Results The sorbent possessed the requisite selectivity for 99 Mo and demonstrated a maximum sorption capacity of 200±5mg Mo/g, which is ~10 times higher than that of ordinary acidic alumina. The overall yield of 99m Tc was >80%, with radionuclidic purity >99.99% and radiochemical purity >99%. The yield of 99m Tc varied from 7.8 to 2.1GBq in the eluate for the six days of operation of the generator. The radioactive concentration of 99m Tc eluted was adequate for the formulation of radiopharmaceuticals. The performance of the generator remained consistent over an extended period of 10days. The eluted 99m Tc was suitable for the formulation of 99m Tc-DMSA and 99m Tc-EC resulting in high radiolabeling yields (>98%). Conclusion The effectiveness of γ-Al 2 O 3 as a new generation sorbent in the development of clinically useful 99 Mo/ 99m Tc generator using low specific activity 99 Mo and yielding 99m Tc with adequate radioactive concentration and high purity suitable for formulation of radiopharmaceuticals is demonstrated.
Teruo Okano - One of the best experts on this subject based on the ideXlab platform.
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Temperature-responsive, polymer-modified surfaces for green chromatography
Macromolecular Symposia, 2004Co-Authors: Akihiko Kikuchi, Teruo OkanoAbstract:Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm) and its derivatives were utilized as chromatography Column Matrix modifiers to develop novel supports for thermoresponsive hydrophobic chromatography with aqueous mobile phase. In the Column, Matrix surfaces show thermoresponsive hydrophilic/hydrophobic property alterations, which alter interaction with and retention of solutes to be separated. We have also demonstrated that the electrostatic interaction of ionic solutes and charged, thermoresponsive polymer-modified surfaces can be modulated temperature changes in the aqueous mobile phase alone.
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Aqueous chromatography utilizing hydrophobicity-modified anionic temperature-responsive hydrogel for stationary phases.
Journal of chromatography. A, 2002Co-Authors: Jun Kobayashi, Akihiko Kikuchi, Kiyotaka Sakai, Teruo OkanoAbstract:A new pH-/temperature-responsive poly(N-isopropylacrylamide-co-acrylic acid-co-N-tert-butylacrylamide) (poly(IPAAm-co-AAc-co-tBAAm)) hydrogel grafted on silica beads was evaluated as Column Matrix for a cation-exchange thermoresponsive chromatography. The stationary phase showed simultaneous changes in temperature-responsive surface charge density and hydrophobicity by incorporation of anionic AAc and hydrophobic tBAAm into IPAAm sequences. Thermoresponsive polymer property alterations were confirmed by temperature-responsive phase transition and shift in apparent pKa values. Catecholamine derivatives were retained on poly(IPAAm-co-AAc-co-tBAAm)-modified Column at pH 7.0. Analyte retention was primarily due to the electrostatic interaction. It was noted that the temperature-induced phase transition of poly(IPAAm-co-AAc-co-tBAAm) hydrogel layer on the stationary phases was evidenced by the apparent inflection point in van't Hoff plots around 36 degrees C. This suggests that solute interactions should be changed below and above the stationary phase transition temperature, reducing electrostatic interaction above the transition temperature.
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Aqueous chromatography utilizing hydrophobicity-modified anionic temperature-responsive hydrogel for stationary phases.
Journal of Chromatography A, 2002Co-Authors: Jun Kobayashi, Akihiko Kikuchi, Kiyotaka Sakai, Teruo OkanoAbstract:Abstract A new pH-/temperature-responsive poly( N -isopropylacrylamide- co -acrylic acid- co - N - tert -butylacrylamide) (poly(IPAAm- co -AAc- co -tBAAm)) hydrogel grafted on silica beads was evaluated as Column Matrix for a cation-exchange thermoresponsive chromatography. The stationary phase showed simultaneous changes in temperature-responsive surface charge density and hydrophobicity by incorporation of anionic AAc and hydrophobic tBAAm into IPAAm sequences. Thermoresponsive polymer property alterations were confirmed by temperature-responsive phase transition and shift in apparent p K a values. Catecholamine derivatives were retained on poly(IPAAm- co -AAc- co -tBAAm)-modified Column at pH 7.0. Analyte retention was primarily due to the electrostatic interaction. It was noted that the temperature-induced phase transition of poly(IPAAm- co -AAc- co -tBAAm) hydrogel layer on the stationary phases was evidenced by the apparent inflection point in van’t Hoff plots around 36 °C. This suggests that solute interactions should be changed below and above the stationary phase transition temperature, reducing electrostatic interaction above the transition temperature.
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Aqueous Chromatography Utilizing pH-/Temperature-Responsive Polymer Stationary Phases To Separate Ionic Bioactive Compounds
Analytical Chemistry, 2001Co-Authors: Jun Kobayashi, Akihiko Kikuchi, Kiyotaka Sakai, Teruo OkanoAbstract:Cross-linked poly(N-isopropylacrylamide-co-acrylic acid) (poly(IPAAm-co-AAc))-grafted silica bead surfaces were prepared and applied as new Column Matrix materials that exploit temperature-responsive anionic chromatography to separate basic bioactive compounds, specifically catecholamine derivatives, in aqueous mobile phases. Since poly(IPAAm-co-AAc) has a well-known temperature-responsive phase transition and apparent pKa shift, polymer-grafted silica bead surfaces are expected to exhibit simultaneous hydrophilic/hydrophobic and charge density alterations under thermal stimuli. Elution behavior of catecholamine derivatives from a copolymer-modified bead packed Column was monitored using aqueous mobile-phase HPLC under varying temperature and pH. Catecholamine derivatives had higher retention times on poly(IPAAm-co-AAc) Columns at higher pH in comparison with those on noncharged PIPAAm reference Columns, suggesting an electrostatic interaction as a separation mode. Temperature also affected the retention ...
Yazhuo Dong - One of the best experts on this subject based on the ideXlab platform.
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Window memory accesses method in alternate row/Column Matrix access systems
2010 2nd International Conference on Computer Engineering and Technology, 2010Co-Authors: Jie Zhou, Yazhuo DongAbstract:Many systems, such as Synthetic Aperture Radar (SAR) processing, two-dimensional image processing, 2d-FFT calculation, need access the row and Column data of their Matrix alternately. The DRAM memory should be used due to huge data in these systems. To improve the usage of memory bandwidth in such systems, this paper theoretically analyses the optimal window size to minimize the total number of opening/closing pages when performing in such instances by balancing the number of handling physical pages between row and Column accesses. This paper presents a window-based optimal memory access method, and we implemented an FPGA-based SDRAM controller with eight simple ports, which is based on window accessing mechanism and supports commercialized SDARM. The experimental results show that the effective I/O bandwidth of external SDRAM using our window layout approach increases from 114.2MB/s of naive implementation to 730.2MB/s with over 6X speedup. In addition, we implemented two SAR processing systems with four FFT processing elements using our window-based SDRAM controller and Corner Turn method separately in FPGA chip. Results show window-based method can achieve a speedup of 2.6 compared to Corner Turn method.
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window memory accesses method in alternate row Column Matrix access systems
International Conference on Computer Engineering and Technology, 2010Co-Authors: Jie Zhou, Yong Dou, Yuanwu Lei, Yazhuo DongAbstract:Many systems, such as Synthetic Aperture Radar (SAR) processing, two-dimensional image processing, 2d-FFT calculation, need access the row and Column data of their Matrix alternately. The DRAM memory should be used due to huge data in these systems. To improve the usage of memory bandwidth in such systems, this paper theoretically analyses the optimal window size to minimize the total number of opening/closing pages when performing in such instances by balancing the number of handling physical pages between row and Column accesses. This paper presents a window-based optimal memory access method, and we implemented an FPGA-based SDRAM controller with eight simple ports, which is based on window accessing mechanism and supports commercialized SDARM. The experimental results show that the effective I/O bandwidth of external SDRAM using our window layout approach increases from 114.2MB/s of naive implementation to 730.2MB/s with over 6X speedup. In addition, we implemented two SAR processing systems with four FFT processing elements using our window-based SDRAM controller and Corner Turn method separately in FPGA chip. Results show window-based method can achieve a speedup of 2.6 compared to Corner Turn method.
Rubel Chakravarty - One of the best experts on this subject based on the ideXlab platform.
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preparation of clinical scale 99mo 99mtc Column generator using neutron activated low specific activity 99mo and nanocrystalline γ al2o3 as Column Matrix
Nuclear Medicine and Biology, 2012Co-Authors: Rubel Chakravarty, Ramu Ram, Ashutosh Dash, M. R. A. PillaiAbstract:Abstract Introduction Preparation of clinical-scale 99 Mo/ 99m Tc generator using (n,γ) activated low specific activity 99 Mo and nanocrystalline γ-Al 2 O 3 as a high capacity sorbent Matrix is attempted. Methods Nanocrystalline γ-Al 2 O 3 was synthesized by ‘solid state mechanochemical' reaction of aluminum nitrate with ammonium bicarbonate. Experimental parameters were optimized to effectively separate 99m Tc from 99 Mo using this sorbent as the Column Matrix. The performance features of a 13GBq (350mCi) 99 Mo/ 99m Tc generator using this sorbent and 99 Mo produced by (n,γ) route having specific activity 12.9–18.5GBq/g were evaluated for 10days. Results The sorbent possessed the requisite selectivity for 99 Mo and demonstrated a maximum sorption capacity of 200±5mg Mo/g, which is ~10 times higher than that of ordinary acidic alumina. The overall yield of 99m Tc was >80%, with radionuclidic purity >99.99% and radiochemical purity >99%. The yield of 99m Tc varied from 7.8 to 2.1GBq in the eluate for the six days of operation of the generator. The radioactive concentration of 99m Tc eluted was adequate for the formulation of radiopharmaceuticals. The performance of the generator remained consistent over an extended period of 10days. The eluted 99m Tc was suitable for the formulation of 99m Tc-DMSA and 99m Tc-EC resulting in high radiolabeling yields (>98%). Conclusion The effectiveness of γ-Al 2 O 3 as a new generation sorbent in the development of clinically useful 99 Mo/ 99m Tc generator using low specific activity 99 Mo and yielding 99m Tc with adequate radioactive concentration and high purity suitable for formulation of radiopharmaceuticals is demonstrated.
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Preparation of clinical-scale 99Mo/99mTc Column generator using neutron activated low specific activity 99Mo and nanocrystalline γ-Al2O3 as Column Matrix.
Nuclear Medicine and Biology, 2012Co-Authors: Rubel Chakravarty, Ramu Ram, Ashutosh Dash, M. R. A. PillaiAbstract:Abstract Introduction Preparation of clinical-scale 99 Mo/ 99m Tc generator using (n,γ) activated low specific activity 99 Mo and nanocrystalline γ-Al 2 O 3 as a high capacity sorbent Matrix is attempted. Methods Nanocrystalline γ-Al 2 O 3 was synthesized by ‘solid state mechanochemical' reaction of aluminum nitrate with ammonium bicarbonate. Experimental parameters were optimized to effectively separate 99m Tc from 99 Mo using this sorbent as the Column Matrix. The performance features of a 13GBq (350mCi) 99 Mo/ 99m Tc generator using this sorbent and 99 Mo produced by (n,γ) route having specific activity 12.9–18.5GBq/g were evaluated for 10days. Results The sorbent possessed the requisite selectivity for 99 Mo and demonstrated a maximum sorption capacity of 200±5mg Mo/g, which is ~10 times higher than that of ordinary acidic alumina. The overall yield of 99m Tc was >80%, with radionuclidic purity >99.99% and radiochemical purity >99%. The yield of 99m Tc varied from 7.8 to 2.1GBq in the eluate for the six days of operation of the generator. The radioactive concentration of 99m Tc eluted was adequate for the formulation of radiopharmaceuticals. The performance of the generator remained consistent over an extended period of 10days. The eluted 99m Tc was suitable for the formulation of 99m Tc-DMSA and 99m Tc-EC resulting in high radiolabeling yields (>98%). Conclusion The effectiveness of γ-Al 2 O 3 as a new generation sorbent in the development of clinically useful 99 Mo/ 99m Tc generator using low specific activity 99 Mo and yielding 99m Tc with adequate radioactive concentration and high purity suitable for formulation of radiopharmaceuticals is demonstrated.
Akihiko Kikuchi - One of the best experts on this subject based on the ideXlab platform.
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Temperature-responsive, polymer-modified surfaces for green chromatography
Macromolecular Symposia, 2004Co-Authors: Akihiko Kikuchi, Teruo OkanoAbstract:Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm) and its derivatives were utilized as chromatography Column Matrix modifiers to develop novel supports for thermoresponsive hydrophobic chromatography with aqueous mobile phase. In the Column, Matrix surfaces show thermoresponsive hydrophilic/hydrophobic property alterations, which alter interaction with and retention of solutes to be separated. We have also demonstrated that the electrostatic interaction of ionic solutes and charged, thermoresponsive polymer-modified surfaces can be modulated temperature changes in the aqueous mobile phase alone.
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Aqueous chromatography utilizing hydrophobicity-modified anionic temperature-responsive hydrogel for stationary phases.
Journal of chromatography. A, 2002Co-Authors: Jun Kobayashi, Akihiko Kikuchi, Kiyotaka Sakai, Teruo OkanoAbstract:A new pH-/temperature-responsive poly(N-isopropylacrylamide-co-acrylic acid-co-N-tert-butylacrylamide) (poly(IPAAm-co-AAc-co-tBAAm)) hydrogel grafted on silica beads was evaluated as Column Matrix for a cation-exchange thermoresponsive chromatography. The stationary phase showed simultaneous changes in temperature-responsive surface charge density and hydrophobicity by incorporation of anionic AAc and hydrophobic tBAAm into IPAAm sequences. Thermoresponsive polymer property alterations were confirmed by temperature-responsive phase transition and shift in apparent pKa values. Catecholamine derivatives were retained on poly(IPAAm-co-AAc-co-tBAAm)-modified Column at pH 7.0. Analyte retention was primarily due to the electrostatic interaction. It was noted that the temperature-induced phase transition of poly(IPAAm-co-AAc-co-tBAAm) hydrogel layer on the stationary phases was evidenced by the apparent inflection point in van't Hoff plots around 36 degrees C. This suggests that solute interactions should be changed below and above the stationary phase transition temperature, reducing electrostatic interaction above the transition temperature.
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Aqueous chromatography utilizing hydrophobicity-modified anionic temperature-responsive hydrogel for stationary phases.
Journal of Chromatography A, 2002Co-Authors: Jun Kobayashi, Akihiko Kikuchi, Kiyotaka Sakai, Teruo OkanoAbstract:Abstract A new pH-/temperature-responsive poly( N -isopropylacrylamide- co -acrylic acid- co - N - tert -butylacrylamide) (poly(IPAAm- co -AAc- co -tBAAm)) hydrogel grafted on silica beads was evaluated as Column Matrix for a cation-exchange thermoresponsive chromatography. The stationary phase showed simultaneous changes in temperature-responsive surface charge density and hydrophobicity by incorporation of anionic AAc and hydrophobic tBAAm into IPAAm sequences. Thermoresponsive polymer property alterations were confirmed by temperature-responsive phase transition and shift in apparent p K a values. Catecholamine derivatives were retained on poly(IPAAm- co -AAc- co -tBAAm)-modified Column at pH 7.0. Analyte retention was primarily due to the electrostatic interaction. It was noted that the temperature-induced phase transition of poly(IPAAm- co -AAc- co -tBAAm) hydrogel layer on the stationary phases was evidenced by the apparent inflection point in van’t Hoff plots around 36 °C. This suggests that solute interactions should be changed below and above the stationary phase transition temperature, reducing electrostatic interaction above the transition temperature.
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Aqueous Chromatography Utilizing pH-/Temperature-Responsive Polymer Stationary Phases To Separate Ionic Bioactive Compounds
Analytical Chemistry, 2001Co-Authors: Jun Kobayashi, Akihiko Kikuchi, Kiyotaka Sakai, Teruo OkanoAbstract:Cross-linked poly(N-isopropylacrylamide-co-acrylic acid) (poly(IPAAm-co-AAc))-grafted silica bead surfaces were prepared and applied as new Column Matrix materials that exploit temperature-responsive anionic chromatography to separate basic bioactive compounds, specifically catecholamine derivatives, in aqueous mobile phases. Since poly(IPAAm-co-AAc) has a well-known temperature-responsive phase transition and apparent pKa shift, polymer-grafted silica bead surfaces are expected to exhibit simultaneous hydrophilic/hydrophobic and charge density alterations under thermal stimuli. Elution behavior of catecholamine derivatives from a copolymer-modified bead packed Column was monitored using aqueous mobile-phase HPLC under varying temperature and pH. Catecholamine derivatives had higher retention times on poly(IPAAm-co-AAc) Columns at higher pH in comparison with those on noncharged PIPAAm reference Columns, suggesting an electrostatic interaction as a separation mode. Temperature also affected the retention ...