The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Gerhard Klimeck - One of the best experts on this subject based on the ideXlab platform.
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Non-Primitive rectangular Cells for tight-binding electronic structure calculations
Physica E: Low-dimensional Systems and Nanostructures, 2009Co-Authors: Timothy B. Boykin, Neerav Kharche, Gerhard KlimeckAbstract:Rectangular non-Primitive unit Cells are computationally convenient for use in nanodevice electronic structure and transport calculations. When these Cells are used for calculations of structures with periodicity, the resulting bands are zone-folded and must be unfolded in order to identify important gaps and masses. Before the zone-unfolding method can be applied, one must first determine the allowed wavevectors for the specific non-Primitive Cell. Because most computationally convenient non-Primitive Cells do not have axes parallel to the Primitive Cell direct lattice vectors, finding the allowed wavevectors is generally a non-trivial task. (Solid state texts generally treat only the simplest case in which the non-Primitive and Primitive Cell axes are all aligned.) Rectangular non-Primitive Cells with one axis aligned along a specific direction are especially useful for obtaining the approximate random-alloy bands for a bulk crystal, a critical verification step in any random-alloy nanostructure calculation. Here, we present an easily implemented method for determining a non-Primitive rectangular Cell for the FCC lattice with an axis aligned in a desired direction and the associated allowed Primitive Cell wavevectors. We illustrate its use by unfolding the bands of Ge.
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Brillouin-zone Unfolding of Perfect SuperCells Having Nonequivalent Primitive Cells Illustrated with a Si/Ge Tight-Binding parameterization
Physical Review B, 2007Co-Authors: Timothy B. Boykin, Neerav Kharche, Gerhard KlimeckAbstract:Numerical calculations of nanostructure electronic properties are often based on a nonPrimitive rectangular unit Cell, because the rectangular geometry allows for both highly efficient algorithms and ease of debugging while having no drawback in calculating quantum dot energy levels or the one-dimensional energy bands of nanowires. Since general nanostructure programs can also handle superlattices, it is natural to apply them to these structures as well, but here problems arise due to the fact that the rectangular unit Cell is generally not the Primitive Cell of the superlattice, so that the resulting E! k" relations must be unfolded to obtain the PrimitiveCell E! k" curves. If all of the Primitive Cells in the rectangular unit Cell are identical, then the unfolding is reasonably straightforward; if not, the problem becomes more difficult. Here, we provide a method for zone unfolding when the Primitive Cells in a rectangular Cell are not all identical. The method is applied to a Si! 4" Ge! 4" superlattice using a set of optimized Si and Ge tight-binding strain parameters.
Annalisa Mancini - One of the best experts on this subject based on the ideXlab platform.
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THOC5/FMIP, an mRNA export TREX complex protein, is essential for hematopoietic Primitive Cell survival in vivo
BMC Biology, 2010Co-Authors: Annalisa Mancini, Susanne C Niemann-seyde, Rüdiger Pankow, Omar El Bounkari, Sabine Klebba-färber, Alexandra Koch, Ewa Jaworska, Elaine Spooncer, Achim D Gruber, Anthony D WhettonAbstract:Background The transcription/export complex is evolutionarily conserved from yeast to man and is required for coupled transcription elongation and nuclear export of mRNAs. FMIP(Fms interacting protein) is a member of the THO (suppressors of the transcriptional defects of hpr1delta by overexpression) complex which is a subcomplex of the transcription/export complex. THO complex (THOC) components are not essential for bulk poly (A)+ RNA export in higher eukaryotes, but for the nuclear export of subset of mRNAs, however, their exact role is still unclear. Results To study the role of THOC5/Fms interacting protein in vivo , we generated THOC5/Fms interacting protein knockout mice. Since these mice are embryonic lethal, we then generated interferon inducible conditional THOC5/Fms interacting protein knockout mice. After three poly injections all of the mice died within 14 days. No pathological alterations, however, were observed in liver, kidney or heart. Thus we considered the hematopoietic system and found that seven days after poly injection, the number of blood Cells in peripheral blood decreased drastically. Investigation of bone marrow Cells showed that these became apoptotic within seven days after poly injection. Committed myeloid progenitor Cells and Cells with long term reconstituting potential were lost from bone marrow within four days after poly injection. Furthermore, infusion of normal bone marrow Cells rescued mice from death induced by loss of THOC5/Fms interacting protein. Conclusion THOC5/Fms interacting protein is an essential element in the maintenance of hematopoiesis. Furthermore, mechanistically depletion of THOC5/Fms interacting protein causes the down-regulation of its direct interacting partner, THOC1 which may contribute to altered THO complex function and Cell death.
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thoc5 fmip an mrna export trex complex protein is essential for hematopoietic Primitive Cell survival in vivo
BMC Biology, 2010Co-Authors: Annalisa Mancini, Rüdiger Pankow, Omar El Bounkari, Alexandra Koch, Ewa Jaworska, Elaine Spooncer, Susanne C Niemannseyde, Sabine Klebbafarber, Achim D GruberAbstract:The transcription/export complex is evolutionarily conserved from yeast to man and is required for coupled transcription elongation and nuclear export of mRNAs. FMIP(Fms interacting protein) is a member of the THO (suppressors of the transcriptional defects of hpr1delta by overexpression) complex which is a subcomplex of the transcription/export complex. THO complex (THOC) components are not essential for bulk poly (A)+ RNA export in higher eukaryotes, but for the nuclear export of subset of mRNAs, however, their exact role is still unclear. To study the role of THOC5/Fms interacting protein in vivo, we generated THOC5/Fms interacting protein knockout mice. Since these mice are embryonic lethal, we then generated interferon inducible conditional THOC5/Fms interacting protein knockout mice. After three poly injections all of the mice died within 14 days. No pathological alterations, however, were observed in liver, kidney or heart. Thus we considered the hematopoietic system and found that seven days after poly injection, the number of blood Cells in peripheral blood decreased drastically. Investigation of bone marrow Cells showed that these became apoptotic within seven days after poly injection. Committed myeloid progenitor Cells and Cells with long term reconstituting potential were lost from bone marrow within four days after poly injection. Furthermore, infusion of normal bone marrow Cells rescued mice from death induced by loss of THOC5/Fms interacting protein. THOC5/Fms interacting protein is an essential element in the maintenance of hematopoiesis. Furthermore, mechanistically depletion of THOC5/Fms interacting protein causes the down-regulation of its direct interacting partner, THOC1 which may contribute to altered THO complex function and Cell death.
Timothy B. Boykin - One of the best experts on this subject based on the ideXlab platform.
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Effective bandstructures from unfolding superCells with vacancies
Physica B: Condensed Matter, 2018Co-Authors: Timothy B. Boykin, Arvind AjoyAbstract:Abstract We study how vacancies alter the effective Primitive Cell bands projected out of superCell eigenstates via Brillouin zone unfolding. Two types of vacant Primitive Cells are of particular interest: Fully vacant, in which all atoms in a single Cell are missing; and net fully vacant, in which the atoms comprising a full set for a single Cell are missing from more than one Cell. We find that a fully vacant Primitive Cell and a net fully vacant Primitive Cell have the same effect on the Primitive Cell bands. We show that the probability reduction for any Primitive Cell band is the same, regardless of band or wavevector in the Primitive Cell Brillouin zone, for both fully and net fully vacant Primitive Cells. We illustrate these results with a two-band model.
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Non-Primitive rectangular Cells for tight-binding electronic structure calculations
Physica E: Low-dimensional Systems and Nanostructures, 2009Co-Authors: Timothy B. Boykin, Neerav Kharche, Gerhard KlimeckAbstract:Rectangular non-Primitive unit Cells are computationally convenient for use in nanodevice electronic structure and transport calculations. When these Cells are used for calculations of structures with periodicity, the resulting bands are zone-folded and must be unfolded in order to identify important gaps and masses. Before the zone-unfolding method can be applied, one must first determine the allowed wavevectors for the specific non-Primitive Cell. Because most computationally convenient non-Primitive Cells do not have axes parallel to the Primitive Cell direct lattice vectors, finding the allowed wavevectors is generally a non-trivial task. (Solid state texts generally treat only the simplest case in which the non-Primitive and Primitive Cell axes are all aligned.) Rectangular non-Primitive Cells with one axis aligned along a specific direction are especially useful for obtaining the approximate random-alloy bands for a bulk crystal, a critical verification step in any random-alloy nanostructure calculation. Here, we present an easily implemented method for determining a non-Primitive rectangular Cell for the FCC lattice with an axis aligned in a desired direction and the associated allowed Primitive Cell wavevectors. We illustrate its use by unfolding the bands of Ge.
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Brillouin-zone Unfolding of Perfect SuperCells Having Nonequivalent Primitive Cells Illustrated with a Si/Ge Tight-Binding parameterization
Physical Review B, 2007Co-Authors: Timothy B. Boykin, Neerav Kharche, Gerhard KlimeckAbstract:Numerical calculations of nanostructure electronic properties are often based on a nonPrimitive rectangular unit Cell, because the rectangular geometry allows for both highly efficient algorithms and ease of debugging while having no drawback in calculating quantum dot energy levels or the one-dimensional energy bands of nanowires. Since general nanostructure programs can also handle superlattices, it is natural to apply them to these structures as well, but here problems arise due to the fact that the rectangular unit Cell is generally not the Primitive Cell of the superlattice, so that the resulting E! k" relations must be unfolded to obtain the PrimitiveCell E! k" curves. If all of the Primitive Cells in the rectangular unit Cell are identical, then the unfolding is reasonably straightforward; if not, the problem becomes more difficult. Here, we provide a method for zone unfolding when the Primitive Cells in a rectangular Cell are not all identical. The method is applied to a Si! 4" Ge! 4" superlattice using a set of optimized Si and Ge tight-binding strain parameters.
Achim D Gruber - One of the best experts on this subject based on the ideXlab platform.
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THOC5/FMIP, an mRNA export TREX complex protein, is essential for hematopoietic Primitive Cell survival in vivo
BMC Biology, 2010Co-Authors: Annalisa Mancini, Susanne C Niemann-seyde, Rüdiger Pankow, Omar El Bounkari, Sabine Klebba-färber, Alexandra Koch, Ewa Jaworska, Elaine Spooncer, Achim D Gruber, Anthony D WhettonAbstract:Background The transcription/export complex is evolutionarily conserved from yeast to man and is required for coupled transcription elongation and nuclear export of mRNAs. FMIP(Fms interacting protein) is a member of the THO (suppressors of the transcriptional defects of hpr1delta by overexpression) complex which is a subcomplex of the transcription/export complex. THO complex (THOC) components are not essential for bulk poly (A)+ RNA export in higher eukaryotes, but for the nuclear export of subset of mRNAs, however, their exact role is still unclear. Results To study the role of THOC5/Fms interacting protein in vivo , we generated THOC5/Fms interacting protein knockout mice. Since these mice are embryonic lethal, we then generated interferon inducible conditional THOC5/Fms interacting protein knockout mice. After three poly injections all of the mice died within 14 days. No pathological alterations, however, were observed in liver, kidney or heart. Thus we considered the hematopoietic system and found that seven days after poly injection, the number of blood Cells in peripheral blood decreased drastically. Investigation of bone marrow Cells showed that these became apoptotic within seven days after poly injection. Committed myeloid progenitor Cells and Cells with long term reconstituting potential were lost from bone marrow within four days after poly injection. Furthermore, infusion of normal bone marrow Cells rescued mice from death induced by loss of THOC5/Fms interacting protein. Conclusion THOC5/Fms interacting protein is an essential element in the maintenance of hematopoiesis. Furthermore, mechanistically depletion of THOC5/Fms interacting protein causes the down-regulation of its direct interacting partner, THOC1 which may contribute to altered THO complex function and Cell death.
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thoc5 fmip an mrna export trex complex protein is essential for hematopoietic Primitive Cell survival in vivo
BMC Biology, 2010Co-Authors: Annalisa Mancini, Rüdiger Pankow, Omar El Bounkari, Alexandra Koch, Ewa Jaworska, Elaine Spooncer, Susanne C Niemannseyde, Sabine Klebbafarber, Achim D GruberAbstract:The transcription/export complex is evolutionarily conserved from yeast to man and is required for coupled transcription elongation and nuclear export of mRNAs. FMIP(Fms interacting protein) is a member of the THO (suppressors of the transcriptional defects of hpr1delta by overexpression) complex which is a subcomplex of the transcription/export complex. THO complex (THOC) components are not essential for bulk poly (A)+ RNA export in higher eukaryotes, but for the nuclear export of subset of mRNAs, however, their exact role is still unclear. To study the role of THOC5/Fms interacting protein in vivo, we generated THOC5/Fms interacting protein knockout mice. Since these mice are embryonic lethal, we then generated interferon inducible conditional THOC5/Fms interacting protein knockout mice. After three poly injections all of the mice died within 14 days. No pathological alterations, however, were observed in liver, kidney or heart. Thus we considered the hematopoietic system and found that seven days after poly injection, the number of blood Cells in peripheral blood decreased drastically. Investigation of bone marrow Cells showed that these became apoptotic within seven days after poly injection. Committed myeloid progenitor Cells and Cells with long term reconstituting potential were lost from bone marrow within four days after poly injection. Furthermore, infusion of normal bone marrow Cells rescued mice from death induced by loss of THOC5/Fms interacting protein. THOC5/Fms interacting protein is an essential element in the maintenance of hematopoiesis. Furthermore, mechanistically depletion of THOC5/Fms interacting protein causes the down-regulation of its direct interacting partner, THOC1 which may contribute to altered THO complex function and Cell death.
Yong-wei Zhang - One of the best experts on this subject based on the ideXlab platform.
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A new carbon allotrope: T5-carbon
Scripta Materialia, 2020Co-Authors: Xian-yong Ding, Chao Zhang, Dong-qi Wang, Qingping Wang, Kah-wee Ang, Yong-wei ZhangAbstract:Abstract A novel carbon allotrope is predicted by first-principles calculations. This allotrope is obtained by replacing one of the two atoms in the Primitive Cell of diamond with a carbon tetrahedron, thus it contains five atoms in one Primitive Cell, termed T5-carbon. The stabilities of T5-carbon are checked in structural, thermal and vibrational calculations. T5-carbon is a wide band gap semiconductor with an indirect band gap of 4.30 eV, and has a lattice thermal conductivity of 409 W/mK. Mechanical analyses reveal that T5-carbon shows good mechanical performances. Furthermore, by modifying T5-carbon with replacing some carbon atoms with Si or Ti atoms, we can obtain SiC4 or TiC4 structures. Importantly, the TiC4 system has a moderate conduction and valance band edges, comparable larger absorption capacity of visible light and smaller effective masses of electron and hole carriers than TiO2, confirming its photocatalysis applications.