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Papers by Ricardo A Medina

Research paper thumbnail of The abbreviated pluripotent cell cycle

Human embryonic stem cells (hESCs) and induced pluripotent stem cells proliferate rapidly and div... more Human embryonic stem cells (hESCs) and induced pluripotent stem cells proliferate rapidly and divide symmetrically producing equivalent progeny cells. In contrast, lineage committed cells acquire an extended symmetrical cell cycle. Self-renewal of tissue-specific stem cells is sustained by asymmetric cell division where one progeny cell remains a progenitor while the partner progeny cell exits the cell cycle and differentiates. There are three principal contexts for considering the operation and regulation of the pluripotent cell cycle: temporal, regulatory, and structural. The primary temporal context that the pluripotent self-renewal cell cycle of hESCs is a short G1 period without reducing periods of time allocated to S phase, G2, and mitosis. The rules that govern proliferation in hESCs remain to be comprehensively established. However, several lines of evidence suggest a key role for the naïve transcriptome of hESCs, which is competent to stringently regulate the embryonic stem cell (ESC) cell cycle. This supports the requirements of pluripotent cells to self-propagate while suppressing expression of genes that confer lineage commitment and/or tissue specificity. However, for the first time, we consider unique dimensions to the architectural organization and assembly of regulatory machinery for gene expression in nuclear microenviornments that define parameters of pluripotency. From both fundamental biological and clinical perspectives, understanding control of the abbreviated ESC cycle can provide options to coordinate control of proliferation versus differentiation. Wound healing, tissue engineering, and cell-based therapy to mitigate developmental aberrations illustrate applications that benefit from knowledge of the biology of the pluripotent cell cycle.

Research paper thumbnail of Influence of angle of incidence on seismic demands for inelastic single-storey structures subjected to bi-directional ground motions

Research paper thumbnail of Paper: A PRACTICAL METHOD FOR PROPER MODELING OF STRUCTURAL DAMPING IN INELASTIC PLANE STRUCTURAL SYSTEMS

Research paper thumbnail of Seismic Demands for Performance-Based Design of Frame Structures

SEISMIC DEMANDS FOR PERFORMANCE-BASED DESIGN OF. FRAME STRUCTURES. Ricardo A. MEDINA 1 and Helmut... more SEISMIC DEMANDS FOR PERFORMANCE-BASED DESIGN OF. FRAME STRUCTURES. Ricardo A. MEDINA 1 and Helmut KRAWINKLER 2. ABSTRACT. This paper focuses on the presentation of results for engineering demand ...

Research paper thumbnail of Pacific Earthquake Engineering Research Center

... Jennifer N. Swift University of Southern California Sean Devlin US Geological Survey Yang Zhu... more ... Jennifer N. Swift University of Southern California Sean Devlin US Geological Survey Yang Zhu California Department of Transportation ... Jennifer N. Swift University of Southern California SeanDevlin US Geological Survey Yang Zhu California Department of Transportation ...

Research paper thumbnail of Component Acceleration Demands in Multistory Shear-Wall Structures

This paper deals with the statistical quantification of peak floor acceleration (PFA) demands and... more This paper deals with the statistical quantification of peak floor acceleration (PFA) demands and peak component acceleration (PCA) demands for acceleration‐sensitive nonstructural components attached to or suspended from shear‐wall structures with fundamental periods from 0.15 ...

Research paper thumbnail of Vertical Acceleration Demands on Nonstructural Components in Buildings

Research paper thumbnail of Cyclic Behavior of Deep Steel Columns Subjected to Large Drifts, Rotations, and Axial Loads

Research paper thumbnail of Proposed Method for Probabilistic Estimation of Peak Component Acceleration Demands

Research paper thumbnail of Seismic Collapse Assessment of a 20-Story Steel Moment-Resisting Frame Structure

Research paper thumbnail of Seismic demands for performance-based design

Research paper thumbnail of Collapse assessment of deteriorating SDOF systems

Research paper thumbnail of Seismic drift and ductility demands and their dependence on ground motions

Research paper thumbnail of The histone gene activator HINFP is a nonredundant cyclin E/CDK2 effector during early embryonic cell cycles

Proceedings of The National Academy of Sciences, 2009

Research paper thumbnail of Control of the Human Pluripotent Cell Cycle

From Bench to Bedside, 2010

Human embryonic stem cells (hESCs) have the unique requirement to sustain plasticity through repe... more Human embryonic stem cells (hESCs) have the unique requirement to sustain plasticity through repeated cycles of cell division. While suppressing expression of genes for lineage commitment, these primitive cells retain competency for specialization in response to ...

Research paper thumbnail of In Situ Nuclear Organization of Regulatory Machinery

Methods In Molecular Biology™, 2008

Regulatory machinery for gene expression, replication, and repair are architecturally organized i... more Regulatory machinery for gene expression, replication, and repair are architecturally organized in nuclear microenvironments. This compartmentalization provides threshold concentrations of macromolecules for the organization and assembly of regulatory complexes for combinatorial control. A mechanistic under standing of biological control requires the combined application of molecular, cellular, biochemical, and in vivo genetic approaches. This chapter provides methodologies to characterize nuclear organization of regulatory machinery by in situ immunofluorescence microscopy.

Research paper thumbnail of Seismic Acceleration Demands on Nonstructural Components Attached to Elastic and Inelastic Structures

Improving the Seismic Performance of Existing Buildings and Other Structures, 2009

This paper addresses the quantification of peak component acceleration demands for acceleration‐s... more This paper addresses the quantification of peak component acceleration demands for acceleration‐sensitive nonstructural components attached to or suspended from inelastic structural wall and moment‐resisting frame structures. Under certain conditions, for a given ground ...

Research paper thumbnail of Tyrosine phosphorylation controls Runx2-mediated subnuclear targeting of YAP to repress transcription

Research paper thumbnail of Improved probabilistic quantification of drift demands for seismic evaluation

Research paper thumbnail of Identification of HiNF-P, a Key Activator of Cell Cycle-Controlled Histone H4 Genes at the Onset of S Phase

Molecular and Cellular Biology, 2003

Research paper thumbnail of The abbreviated pluripotent cell cycle

Human embryonic stem cells (hESCs) and induced pluripotent stem cells proliferate rapidly and div... more Human embryonic stem cells (hESCs) and induced pluripotent stem cells proliferate rapidly and divide symmetrically producing equivalent progeny cells. In contrast, lineage committed cells acquire an extended symmetrical cell cycle. Self-renewal of tissue-specific stem cells is sustained by asymmetric cell division where one progeny cell remains a progenitor while the partner progeny cell exits the cell cycle and differentiates. There are three principal contexts for considering the operation and regulation of the pluripotent cell cycle: temporal, regulatory, and structural. The primary temporal context that the pluripotent self-renewal cell cycle of hESCs is a short G1 period without reducing periods of time allocated to S phase, G2, and mitosis. The rules that govern proliferation in hESCs remain to be comprehensively established. However, several lines of evidence suggest a key role for the naïve transcriptome of hESCs, which is competent to stringently regulate the embryonic stem cell (ESC) cell cycle. This supports the requirements of pluripotent cells to self-propagate while suppressing expression of genes that confer lineage commitment and/or tissue specificity. However, for the first time, we consider unique dimensions to the architectural organization and assembly of regulatory machinery for gene expression in nuclear microenviornments that define parameters of pluripotency. From both fundamental biological and clinical perspectives, understanding control of the abbreviated ESC cycle can provide options to coordinate control of proliferation versus differentiation. Wound healing, tissue engineering, and cell-based therapy to mitigate developmental aberrations illustrate applications that benefit from knowledge of the biology of the pluripotent cell cycle.

Research paper thumbnail of Influence of angle of incidence on seismic demands for inelastic single-storey structures subjected to bi-directional ground motions

Research paper thumbnail of Paper: A PRACTICAL METHOD FOR PROPER MODELING OF STRUCTURAL DAMPING IN INELASTIC PLANE STRUCTURAL SYSTEMS

Research paper thumbnail of Seismic Demands for Performance-Based Design of Frame Structures

SEISMIC DEMANDS FOR PERFORMANCE-BASED DESIGN OF. FRAME STRUCTURES. Ricardo A. MEDINA 1 and Helmut... more SEISMIC DEMANDS FOR PERFORMANCE-BASED DESIGN OF. FRAME STRUCTURES. Ricardo A. MEDINA 1 and Helmut KRAWINKLER 2. ABSTRACT. This paper focuses on the presentation of results for engineering demand ...

Research paper thumbnail of Pacific Earthquake Engineering Research Center

... Jennifer N. Swift University of Southern California Sean Devlin US Geological Survey Yang Zhu... more ... Jennifer N. Swift University of Southern California Sean Devlin US Geological Survey Yang Zhu California Department of Transportation ... Jennifer N. Swift University of Southern California SeanDevlin US Geological Survey Yang Zhu California Department of Transportation ...

Research paper thumbnail of Component Acceleration Demands in Multistory Shear-Wall Structures

This paper deals with the statistical quantification of peak floor acceleration (PFA) demands and... more This paper deals with the statistical quantification of peak floor acceleration (PFA) demands and peak component acceleration (PCA) demands for acceleration‐sensitive nonstructural components attached to or suspended from shear‐wall structures with fundamental periods from 0.15 ...

Research paper thumbnail of Vertical Acceleration Demands on Nonstructural Components in Buildings

Research paper thumbnail of Cyclic Behavior of Deep Steel Columns Subjected to Large Drifts, Rotations, and Axial Loads

Research paper thumbnail of Proposed Method for Probabilistic Estimation of Peak Component Acceleration Demands

Research paper thumbnail of Seismic Collapse Assessment of a 20-Story Steel Moment-Resisting Frame Structure

Research paper thumbnail of Seismic demands for performance-based design

Research paper thumbnail of Collapse assessment of deteriorating SDOF systems

Research paper thumbnail of Seismic drift and ductility demands and their dependence on ground motions

Research paper thumbnail of The histone gene activator HINFP is a nonredundant cyclin E/CDK2 effector during early embryonic cell cycles

Proceedings of The National Academy of Sciences, 2009

Research paper thumbnail of Control of the Human Pluripotent Cell Cycle

From Bench to Bedside, 2010

Human embryonic stem cells (hESCs) have the unique requirement to sustain plasticity through repe... more Human embryonic stem cells (hESCs) have the unique requirement to sustain plasticity through repeated cycles of cell division. While suppressing expression of genes for lineage commitment, these primitive cells retain competency for specialization in response to ...

Research paper thumbnail of In Situ Nuclear Organization of Regulatory Machinery

Methods In Molecular Biology™, 2008

Regulatory machinery for gene expression, replication, and repair are architecturally organized i... more Regulatory machinery for gene expression, replication, and repair are architecturally organized in nuclear microenvironments. This compartmentalization provides threshold concentrations of macromolecules for the organization and assembly of regulatory complexes for combinatorial control. A mechanistic under standing of biological control requires the combined application of molecular, cellular, biochemical, and in vivo genetic approaches. This chapter provides methodologies to characterize nuclear organization of regulatory machinery by in situ immunofluorescence microscopy.

Research paper thumbnail of Seismic Acceleration Demands on Nonstructural Components Attached to Elastic and Inelastic Structures

Improving the Seismic Performance of Existing Buildings and Other Structures, 2009

This paper addresses the quantification of peak component acceleration demands for acceleration‐s... more This paper addresses the quantification of peak component acceleration demands for acceleration‐sensitive nonstructural components attached to or suspended from inelastic structural wall and moment‐resisting frame structures. Under certain conditions, for a given ground ...

Research paper thumbnail of Tyrosine phosphorylation controls Runx2-mediated subnuclear targeting of YAP to repress transcription

Research paper thumbnail of Improved probabilistic quantification of drift demands for seismic evaluation

Research paper thumbnail of Identification of HiNF-P, a Key Activator of Cell Cycle-Controlled Histone H4 Genes at the Onset of S Phase

Molecular and Cellular Biology, 2003