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Akira Matsuda - One of the best experts on this subject based on the ideXlab platform.
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Alternate-strand triple-helix formation by the 3′-3′-linked oligodeoxynucleotides with the intercalators at the Junction Point
Nucleic acids research. Supplement (2001), 2001Co-Authors: Yoshihito Ueno, Mai Mikawa, Shuichi Hoshika, Masako Takeba, Yukio Kitade, Akira MatsudaAbstract:3'-3'-Linked oligodeoxynucleotides (ODNs) with the anthraquinonyl group at the Junction Point were synthesized on a DNA synthesizer using a controlled pore glass (CPG), which has pentaerythritol carrying the intercalator at one of the four hydroxymethyl groups. Stability of the triplexes with the target duplexes was studied by thermal denaturation. The 3'-3'-linked ODNs with the anthraquinonyl group enhanced the thermal stability of the triplexes when compared with those without the intercalator and the unmodified nonamer. The inhibitory activity of the 3'-3'-linked ODNs against the cleavage of the target DNA by the restriction enzyme Hind III was tested. It was found that the 3'-3'-linked ODN with the anthraquinonyl group at the Junction Point inhibited the cleavage by the enzyme more effectively than the nonamer and the 3'-3'-linked ODN without the intercalator.
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nucleosides and nucleotides 208 alternate strand triple helix formation by the 3 3 linked oligodeoxynucleotides with the anthraquinonyl group at the Junction Point
Bioconjugate Chemistry, 2001Co-Authors: Yoshihito Ueno, Mai Mikawa, Shuichi Hoshika, Akira MatsudaAbstract:The synthesis of 3'-3'-linked oligodeoxynucleotides (ODNs) with the anthraquinonyl group at the Junction Point is described. The ODNs were synthesized on a DNA synthesizer using a controlled pore glass (CPG) carrying pentaerythritol that has an intercalator at one of the four hydroxymethyl groups. Stability of the triplexes with the target duplexes was studied by thermal denaturation. The 3'-3'-linked ODNs with the anthraquinonyl group enhanced the thermal stability of the triplexes when compared with those without the intercalator and the unmodified nonamer 10. It was found that the ODNs 12 and 13 carrying the anthraquinonyl groups can form thermally stable triplexes by skipping two or three extra base pairs between two binding domains of the target duplexes. The ability of the 3'-3'-linked ODNs to inhibit cleavage of the target DNA 22 by the restriction enzyme Hind III was tested. It was found that the 3'-3'-linked ODN 16 with the anthraquinonyl group at the Junction Point inhibited the cleavage by the enzyme more effectively than the nonamer 14 and the 3'-3'-linked ODN 15 without the intercalator.
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Nucleosides and Nucleotides. 208. Alternate-Strand Triple-Helix Formation by the 3‘-3‘-Linked Oligodeoxynucleotides with the Anthraquinonyl Group at the Junction Point†
Bioconjugate chemistry, 2001Co-Authors: Yoshihito Ueno, Mai Mikawa, Shuichi Hoshika, Akira MatsudaAbstract:The synthesis of 3'-3'-linked oligodeoxynucleotides (ODNs) with the anthraquinonyl group at the Junction Point is described. The ODNs were synthesized on a DNA synthesizer using a controlled pore glass (CPG) carrying pentaerythritol that has an intercalator at one of the four hydroxymethyl groups. Stability of the triplexes with the target duplexes was studied by thermal denaturation. The 3'-3'-linked ODNs with the anthraquinonyl group enhanced the thermal stability of the triplexes when compared with those without the intercalator and the unmodified nonamer 10. It was found that the ODNs 12 and 13 carrying the anthraquinonyl groups can form thermally stable triplexes by skipping two or three extra base pairs between two binding domains of the target duplexes. The ability of the 3'-3'-linked ODNs to inhibit cleavage of the target DNA 22 by the restriction enzyme Hind III was tested. It was found that the 3'-3'-linked ODN 16 with the anthraquinonyl group at the Junction Point inhibited the cleavage by the enzyme more effectively than the nonamer 14 and the 3'-3'-linked ODN 15 without the intercalator.
Nikos Hadjichristidis - One of the best experts on this subject based on the ideXlab platform.
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effect of Junction Point functionality on the lamellar spacing of symmetric ps n pi n miktoarm star block copolymers
Macromolecules, 2003Co-Authors: Yuqing Zhu, Samuel P. Gido, Maria Moshakou, Hermis Iatrou, Nikos Hadjichristidis, Soo-jin Park, Taihyun ChangAbstract:To probe the effect of Junction Point functionality in miktoarm star block copolymer architecture on chain conformation and morphology, a series of AnBn miktoarm star copolymers where A arms are PS blocks and B arms are PI blocks were investigated. The overall series including a diblock and the star block copolymers can be represented by AnBn, where n = 1, 2, 4, and 16. These materials were produced by synthesizing a single batch of living PS arms and a single batch of living PI arms and then linking them together with chlorosilane coupling agents of different functionality. Thus, all PS arms are identical and all PI arms are identical across the entire series of materials. All stars in the series have equal numbers of PS and PI arms, and the volume fractions of all the samples in the series (nearly 0.50 PS by volume) are identical within experimental error. All the materials were found, via small-angle X-ray scattering and transmission electron microscopy, to form lamellar morphologies. A significant inc...
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Effect of Junction Point functionality on the lamellar spacing of symmetric (PS)n(PI)n miktoarm star block copolymers
Macromolecules, 2003Co-Authors: Yuqing Zhu, Samuel P. Gido, Maria Moshakou, Hermis Iatrou, Nikos Hadjichristidis, Soo-jin Park, Taihyun ChangAbstract:To probe the effect of Junction Point functionality in miktoarm star block copolymer architecture on chain conformation and morphology, a series of AnBn miktoarm star copolymers where A arms are PS blocks and B arms are PI blocks were investigated. The overall series including a diblock and the star block copolymers can be represented by AnBn where n = 1, 2, 4, and 16. These materials were produced by synthesizing a single batch of living PS arms and a single batch of living PI arms and then linking them together with chlorosilane coupling agents of different functionality. Thus, all PS arms are identical and all PI arms are identical across the entire series of materials. All stars in the series have equal numbers of PS and PI arms, and the volume fractions of all the samples in the series (nearly 0.50 PS by volume) are identical within experimental error. All the materials were found, via small-angle X-ray scattering and transmission electron microscopy, to form lamellar morphologies. A significant increase in lamellar spacing with increasing Junction Point functionality (n) was found in this series of materials and can be attributed to molecular crowding near the Junction Point.open383
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Morphology of Model Graft Copolymers with Randomly Placed Trifunctional and Tetrafunctional Branch Points
Macromolecules, 1998Co-Authors: Maria Xenidou, Samuel P. Gido, Nikos Hadjichristidis, Frederick L. Beyer, Nora Beck TanAbstract:The morphologies of two series of model graft copolymers were studied using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). Both series of materials have monodisperse polybutadiene (PB) backbones and monodisperse polystyrene (PS) graft blocks. In one series there are on average five trifunctional Junction Points randomly distributed along the PB backbone. Each Junction Point grafts one PS block to the backbone. In the other series there are on average four tetrafunctional Junction Points randomly distributed along the PB backbone. Each Junction Point grafts two PS blocks to the backbone. A range of overall PB and PS volume fractions was investigated for both series. These materials simulate a controlled and known degree of architectural disorder. Current theory cannot rigorously predict the morphological behavior for these complex molecular architectures. However, it is found that an approximate extension of existing theory utilizing the constituting block copolymer (fundam...
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Junction Point fluctuations in microphase separated polystyrene polyisoprene polystyrene triblock copolymer melts a dielectric and rheological investigation
Macromolecules, 1997Co-Authors: Ingo Alig, George Floudas, Apostolos Avgeropoulos, Nikos HadjichristidisAbstract:Dielectric spectroscopy is employed in two polystyrene−polyisoprene−polystyrene (SIS) triblock copolymers well below the order-to-disorder transition temperature and in the frequency range from 10-2 to 106 Hz. Small angle X-ray scattering has shown the formation of lamellar structures with a long period of about 25 nm. Besides the polyisoprene and polystyrene segmental relaxations and a slower process associated with the reorientation of the interface, we provide evidence for a new type of chain dynamics associated with the mobility of the Junction Points at the interface. From the relaxation strength of this processwhich is very much reduced as compared to the chain relaxation in bulk polyisoprenewe extract a characteristic length of the end-to-end vector fluctuations in the interface in the range 4−6 nm. This value compares well with an independent estimate of the interfacial thickness based on thermodynamics. Dielectric spectroscopy can therefore be used as a dynamic probe of the interface in ordered t...
Taihyun Chang - One of the best experts on this subject based on the ideXlab platform.
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effect of Junction Point functionality on the lamellar spacing of symmetric ps n pi n miktoarm star block copolymers
Macromolecules, 2003Co-Authors: Yuqing Zhu, Samuel P. Gido, Maria Moshakou, Hermis Iatrou, Nikos Hadjichristidis, Soo-jin Park, Taihyun ChangAbstract:To probe the effect of Junction Point functionality in miktoarm star block copolymer architecture on chain conformation and morphology, a series of AnBn miktoarm star copolymers where A arms are PS blocks and B arms are PI blocks were investigated. The overall series including a diblock and the star block copolymers can be represented by AnBn, where n = 1, 2, 4, and 16. These materials were produced by synthesizing a single batch of living PS arms and a single batch of living PI arms and then linking them together with chlorosilane coupling agents of different functionality. Thus, all PS arms are identical and all PI arms are identical across the entire series of materials. All stars in the series have equal numbers of PS and PI arms, and the volume fractions of all the samples in the series (nearly 0.50 PS by volume) are identical within experimental error. All the materials were found, via small-angle X-ray scattering and transmission electron microscopy, to form lamellar morphologies. A significant inc...
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Effect of Junction Point functionality on the lamellar spacing of symmetric (PS)n(PI)n miktoarm star block copolymers
Macromolecules, 2003Co-Authors: Yuqing Zhu, Samuel P. Gido, Maria Moshakou, Hermis Iatrou, Nikos Hadjichristidis, Soo-jin Park, Taihyun ChangAbstract:To probe the effect of Junction Point functionality in miktoarm star block copolymer architecture on chain conformation and morphology, a series of AnBn miktoarm star copolymers where A arms are PS blocks and B arms are PI blocks were investigated. The overall series including a diblock and the star block copolymers can be represented by AnBn where n = 1, 2, 4, and 16. These materials were produced by synthesizing a single batch of living PS arms and a single batch of living PI arms and then linking them together with chlorosilane coupling agents of different functionality. Thus, all PS arms are identical and all PI arms are identical across the entire series of materials. All stars in the series have equal numbers of PS and PI arms, and the volume fractions of all the samples in the series (nearly 0.50 PS by volume) are identical within experimental error. All the materials were found, via small-angle X-ray scattering and transmission electron microscopy, to form lamellar morphologies. A significant increase in lamellar spacing with increasing Junction Point functionality (n) was found in this series of materials and can be attributed to molecular crowding near the Junction Point.open383
Yoshihito Ueno - One of the best experts on this subject based on the ideXlab platform.
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Alternate-strand triple-helix formation by the 3′-3′-linked oligodeoxynucleotides with the intercalators at the Junction Point
Nucleic acids research. Supplement (2001), 2001Co-Authors: Yoshihito Ueno, Mai Mikawa, Shuichi Hoshika, Masako Takeba, Yukio Kitade, Akira MatsudaAbstract:3'-3'-Linked oligodeoxynucleotides (ODNs) with the anthraquinonyl group at the Junction Point were synthesized on a DNA synthesizer using a controlled pore glass (CPG), which has pentaerythritol carrying the intercalator at one of the four hydroxymethyl groups. Stability of the triplexes with the target duplexes was studied by thermal denaturation. The 3'-3'-linked ODNs with the anthraquinonyl group enhanced the thermal stability of the triplexes when compared with those without the intercalator and the unmodified nonamer. The inhibitory activity of the 3'-3'-linked ODNs against the cleavage of the target DNA by the restriction enzyme Hind III was tested. It was found that the 3'-3'-linked ODN with the anthraquinonyl group at the Junction Point inhibited the cleavage by the enzyme more effectively than the nonamer and the 3'-3'-linked ODN without the intercalator.
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nucleosides and nucleotides 208 alternate strand triple helix formation by the 3 3 linked oligodeoxynucleotides with the anthraquinonyl group at the Junction Point
Bioconjugate Chemistry, 2001Co-Authors: Yoshihito Ueno, Mai Mikawa, Shuichi Hoshika, Akira MatsudaAbstract:The synthesis of 3'-3'-linked oligodeoxynucleotides (ODNs) with the anthraquinonyl group at the Junction Point is described. The ODNs were synthesized on a DNA synthesizer using a controlled pore glass (CPG) carrying pentaerythritol that has an intercalator at one of the four hydroxymethyl groups. Stability of the triplexes with the target duplexes was studied by thermal denaturation. The 3'-3'-linked ODNs with the anthraquinonyl group enhanced the thermal stability of the triplexes when compared with those without the intercalator and the unmodified nonamer 10. It was found that the ODNs 12 and 13 carrying the anthraquinonyl groups can form thermally stable triplexes by skipping two or three extra base pairs between two binding domains of the target duplexes. The ability of the 3'-3'-linked ODNs to inhibit cleavage of the target DNA 22 by the restriction enzyme Hind III was tested. It was found that the 3'-3'-linked ODN 16 with the anthraquinonyl group at the Junction Point inhibited the cleavage by the enzyme more effectively than the nonamer 14 and the 3'-3'-linked ODN 15 without the intercalator.
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Nucleosides and Nucleotides. 208. Alternate-Strand Triple-Helix Formation by the 3‘-3‘-Linked Oligodeoxynucleotides with the Anthraquinonyl Group at the Junction Point†
Bioconjugate chemistry, 2001Co-Authors: Yoshihito Ueno, Mai Mikawa, Shuichi Hoshika, Akira MatsudaAbstract:The synthesis of 3'-3'-linked oligodeoxynucleotides (ODNs) with the anthraquinonyl group at the Junction Point is described. The ODNs were synthesized on a DNA synthesizer using a controlled pore glass (CPG) carrying pentaerythritol that has an intercalator at one of the four hydroxymethyl groups. Stability of the triplexes with the target duplexes was studied by thermal denaturation. The 3'-3'-linked ODNs with the anthraquinonyl group enhanced the thermal stability of the triplexes when compared with those without the intercalator and the unmodified nonamer 10. It was found that the ODNs 12 and 13 carrying the anthraquinonyl groups can form thermally stable triplexes by skipping two or three extra base pairs between two binding domains of the target duplexes. The ability of the 3'-3'-linked ODNs to inhibit cleavage of the target DNA 22 by the restriction enzyme Hind III was tested. It was found that the 3'-3'-linked ODN 16 with the anthraquinonyl group at the Junction Point inhibited the cleavage by the enzyme more effectively than the nonamer 14 and the 3'-3'-linked ODN 15 without the intercalator.
Samuel P. Gido - One of the best experts on this subject based on the ideXlab platform.
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effect of Junction Point functionality on the lamellar spacing of symmetric ps n pi n miktoarm star block copolymers
Macromolecules, 2003Co-Authors: Yuqing Zhu, Samuel P. Gido, Maria Moshakou, Hermis Iatrou, Nikos Hadjichristidis, Soo-jin Park, Taihyun ChangAbstract:To probe the effect of Junction Point functionality in miktoarm star block copolymer architecture on chain conformation and morphology, a series of AnBn miktoarm star copolymers where A arms are PS blocks and B arms are PI blocks were investigated. The overall series including a diblock and the star block copolymers can be represented by AnBn, where n = 1, 2, 4, and 16. These materials were produced by synthesizing a single batch of living PS arms and a single batch of living PI arms and then linking them together with chlorosilane coupling agents of different functionality. Thus, all PS arms are identical and all PI arms are identical across the entire series of materials. All stars in the series have equal numbers of PS and PI arms, and the volume fractions of all the samples in the series (nearly 0.50 PS by volume) are identical within experimental error. All the materials were found, via small-angle X-ray scattering and transmission electron microscopy, to form lamellar morphologies. A significant inc...
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Effect of Junction Point functionality on the lamellar spacing of symmetric (PS)n(PI)n miktoarm star block copolymers
Macromolecules, 2003Co-Authors: Yuqing Zhu, Samuel P. Gido, Maria Moshakou, Hermis Iatrou, Nikos Hadjichristidis, Soo-jin Park, Taihyun ChangAbstract:To probe the effect of Junction Point functionality in miktoarm star block copolymer architecture on chain conformation and morphology, a series of AnBn miktoarm star copolymers where A arms are PS blocks and B arms are PI blocks were investigated. The overall series including a diblock and the star block copolymers can be represented by AnBn where n = 1, 2, 4, and 16. These materials were produced by synthesizing a single batch of living PS arms and a single batch of living PI arms and then linking them together with chlorosilane coupling agents of different functionality. Thus, all PS arms are identical and all PI arms are identical across the entire series of materials. All stars in the series have equal numbers of PS and PI arms, and the volume fractions of all the samples in the series (nearly 0.50 PS by volume) are identical within experimental error. All the materials were found, via small-angle X-ray scattering and transmission electron microscopy, to form lamellar morphologies. A significant increase in lamellar spacing with increasing Junction Point functionality (n) was found in this series of materials and can be attributed to molecular crowding near the Junction Point.open383
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Morphology of Model Graft Copolymers with Randomly Placed Trifunctional and Tetrafunctional Branch Points
Macromolecules, 1998Co-Authors: Maria Xenidou, Samuel P. Gido, Nikos Hadjichristidis, Frederick L. Beyer, Nora Beck TanAbstract:The morphologies of two series of model graft copolymers were studied using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). Both series of materials have monodisperse polybutadiene (PB) backbones and monodisperse polystyrene (PS) graft blocks. In one series there are on average five trifunctional Junction Points randomly distributed along the PB backbone. Each Junction Point grafts one PS block to the backbone. In the other series there are on average four tetrafunctional Junction Points randomly distributed along the PB backbone. Each Junction Point grafts two PS blocks to the backbone. A range of overall PB and PS volume fractions was investigated for both series. These materials simulate a controlled and known degree of architectural disorder. Current theory cannot rigorously predict the morphological behavior for these complex molecular architectures. However, it is found that an approximate extension of existing theory utilizing the constituting block copolymer (fundam...
