VCU Department of Physics Colloquia: Fall 2019
Gene Clustering Drives Transcriptional Coherence of Disparate biological Pathways
Prof. Richard Joh
Department of Physics
Virginia Commonwealth University
Friday, October 11 at 4:00 pm in 701 W. Grace St., Room 2310
The establishment of distinct transcriptional states in response to developmental or environmental cues is critical for survival. This involves the concordant or discordant transcriptional regulation of several distinct biological pathways, often involving thousands of genes, which together enhance survival. How these system-level changes to transcriptomes are coordinated is an understudied problem in eukaryotic biology. Here, using computational approaches in eukaryotes ranging from yeast to human, we report that this transcriptional coordination is in part achieved by the genic proximity of the regulatory nodes of disparate biological
pathways whose co-regulation drives the transcriptional coherence of their respective pathways. Overall, our data identify conserved and species-specific transcriptional co-regulation of hundreds of different biological pathway pairs and suggest that genomic clustering of regulatory nodes such as transcription factors coordinate the expression of thousands of genes, creating tunable regulons in eukaryotes.
The Past, Present, and Future of Quantum Chemistry
Prof. Ka Un Lao
Department of Chemistry
Virginia Commonwealth University
Friday, October 4 at 4:00 pm in 701 W. Grace St., Room 2310
The Lao group is a computational/theoretical group that focuses on developing and applying new electronic structure models and algorithms based on quantum mechanics, combining concepts and techniques from chemistry, physics, mathematics, and computer science, to study molecules, clusters, and condensed phase systems, ranging from chemistry to biochemistry and materials science.
One particular area of emphasis is the accurate and efficient calculation of intermolecular interactions, which is a challenging problem for electronic structure theory. Our research goal is to develop fast and accurate approaches for gaining a
fundamental understanding of the factors governing the drug binding and molecular materials packing in order to provide a basis for the development of new drug binding molecules and functionalized molecular materials.
Furthermore, adapting the methodology we are going to develop to the rapid evolution of machine-learning techniques offers a unique opportunity to generate new noncovalent molecular electronics and drug molecules through large-scale computational screening and design since the combination of different strategies to functionalize molecules is seemingly infinite.
Perspectives on processing magnetocaloric transition-metal borides for solid state cooling applications
Prof. Radhika Barua
College of Engineering,
Virginia Commonwealth University
Friday, September 27 at 4:00 pm in 701 W. Grace St., Room 2310
In the United States, residential and commercial buildings currently account for 72% of the nation's electricity use and 40% of carbon dioxide (CO2) emissions annually, 15% of which originates from air conditioning and refrigeration systems. Novel cooling technologies are required to minimize global energy consumption and environmental impact. To this end, solid state magnetic cooling devices enabled with the “magnetocaloric” class of functional materials are attractive as they allow complete elimination of conventional high-global warming potential (GWP) refrigerants and have the potential for efficiency improvements of up to 25% over conventional vapor compression systems, which is equivalent to 60% of Carnot efficiency
Within this context, this talk will address the major principles guiding the development of magnetocaloric transition-metal borides for active magnetic regenerator (AMR) magnetic cooling devices. Specific attention will be given to current research efforts for processing AlFe2B2 – a rare-earth-free intermetallic alloy that exhibits an appreciable magnetocaloric response corresponding to an adiabatic temperature change of 2.2 K and magnetic entropy change of 4.4 J/kgK at an applied magnetic field of 2 T. Computational and experimental results will be presented to demonstrate that spin-orbit coupling in the layered orthorhombic AlFe2B2 crystal structure results in an anisotropic magnetocrystalline energy, thus producing an associated anisotropic magnetofunctional response. Further, the influence of compositional variation on the magnetic properties of AlFe2B2 will be discussed.
Prof. John Hackett
Department of Physiology and Biophysics and
The Massey Cancer Center
Virginia Commonwealth University
Friday, September 20 at 4:00 pm in 701 W. Grace St., Room 2310
Cytochrome P450 19A1 (CYP19A1, aromatase) required for the synthesis of estrogens from androgens, is among the key targets for treatment of estrogen-dependent cancers. It is representative of other steroidogenic CYPs (i.e. 11A1 ,11B2, 17A1, 51) insofar as it also catalyzes a sequential oxidation and shares structural features at the putative substrate recognition interface. It is one of the few enzymes known to construct an aromatic ring with a controversial mechanism. How steroidogenic CYPs, including CYP19A1, recognize, and in some cases discriminate between very similar substrates remain salient unanswered questions in the field. Little effort has been made to elucidate substrate recognition and discrimination mechanisms of the highly-selective endobiotic-metabolizing CYPs. This colloquium will provide an update on the current state of knowledge of the CYP19A1 catalytic mechanism and summarize our recent efforts to integrate experimental and computational approaches to glean novel insight into the functional dynamics of CYP19A1 in a native-like membrane.
Pool and Flow Boiling Heat Transfer in Variable Gravity Environments
Dr Jungho Kim
Department of Mechanical Engineering
University of Maryland
Friday, September 13 at 4:00 pm in 701 W. Grace St., Room 2310
Knowledge of how gravity affects two-phase heat transfer is critical to the design of equipment (e.g., heat exchangers and nuclear reactors) that will be operated in variable gravity environments (high-g, low-g, lunar, and Martian-g). Relatively little is known about boiling mechanisms in these environments since data from long duration microgravity environments are limited due to high cost and limited flight opportunities. Although a few studies have been performed under high quality microgravity environments on board orbital platforms, most low gravity boiling research has been obtained using drop towers, aircraft, and sounding rockets. The relatively large g-jitter and/or the short periods of microgravity duration of these studies has resulted in confusion about the heat transfer mechanisms. The results of a recent International Space Station experiment the clarifies gravity effects on pool boiling mechanisms will be presented along with a model that can be used to scale boiling data. Recent investigations into flow boiling using temperature sensitive paints will also be discussed.
The September 6 Colloquia Has been Cancelled!
From Fundamental Nuclear Physics to Cancer Instrumentation: Science at Jefferson Lab
Dr. Cynthia Keppel,
Hall Leader
Jefferson Lab
Friday, September 6 at 4:00 pm in 701 W. Grace St., Room 2310
The Thomas Jefferson National Accelerator Facility (Jefferson Lab) underwent a major upgrade, doubling the beam energy to 12 GeV and substantially upgrading the associated experimental equipment. Experiments leveraging this upgrade have been underway for almost two years now, with many new results recently becoming available. An overview of the laboratory and some first data will be presented. In addition, focus will be given to applications of detector technology from the fundamental nuclear physics program to medical instrumentation.