Rana Ashkar

Education:

Ph.D., 2012 - Indiana University , Experimental Condensed Matter Physics

M.S., 2007 - American University of Beirut, Theoretical Particle Physics

B.S., 2003 - Lebanese University, Physics

Experience:

2018 – : Assistant Professor, Physics Department, Virginia Tech

2015-2017: Clifford G. Shull fellow, Oak Ridge National Laboratory

2012-2015: Postdoctoral scholar, NIST Center for Neutron Research & University of Maryland

2007-2012: Research Assistant, Indiana University Center for Exploration of Energy and Matter

Awards:

2015 - Clifford G. Shull Fellowship (Oak Ridge National Lab)

2014 - Service Accolade (NIST Postdoctoral Association)

2013 - Esther L. Kinsley PhD Dissertation Award (Indiana University)

2011 - Certificate of Appreciation (Office of Wemen's Affairs at Indiana University)

2010 - Surface X-ray and Neutron Scattering Fellowship Award

2010 - Indiana University "Women In Sceince Program" Award

Activities:

2018-present: Chair of the APS-CSWP Climate Site Visits Committee

2017-present:  Member of the APS Committee on the Status of Women in Physics

2016-2017:  Chairperson of the "Women in Neutrons Sciences committee", ORNL

2015-2017:  Physics editor for ACM Computers and Society Newsletter

2014-2015: Member of the Post Doc Association leadership team at NIST

2009-2012: Member of the Advisory Board of the “Women In Science Program” run by the Office of Women’s Affairs (OWA) at Indiana University

1. Nanoscale Structure and Dynamics in Biomimetic Membranes

Biological functions of cell membranes are controlled by the dynamic organization and interactions of the membrane's main building blocks, lipid and proteins. For simplicity, synthetic lipid membranes are usually studied as mimics of cell membranes in order to tease out reliable information of the interplay between membrane composition, structure, and dynamics and the resultant membrane functions. Using a suite of techniques including x-ray and neutron scattering and MD simulations, the aim of this project is to understand: 

• nanoscale membrane structure 
• effect of membrane composition on domain formation/structure and interactions 
• fast membrane dynamics and their role in biological functions
• membrane bending and thickness fluctuations
• membrane protein interactions   

2. Topographically Nanostructured Lipid Membranes

This project aims to investigate curvature effects in surface-modulated lipid membranes. This is done by utilizing the tunability of nanopatterned thermoresponsive polymer scaffolds to generate controllable 2D architectures in supported lipid membranes. The premise of this system is that it enables real-time realization of lateral membrane reorganization and peripheral protein binding in response to local membrane curvature, thus providing insights into critical membrane functions such as signal transduction, cell trafficking, and host-pathogen interactions. Further, such tunability of membrane topography can open new avenues to thermally switchable membrane-based biosensors.  

3. Hierarchical Structure and Dynamics in Polymer Nanocomposites

Polymer nanocomposites (PNCs) are promising candidates for advanced multifunctional light-weight materials. The premise of PNCs lies in the myriad of possibilities they offer in synergistically integrating particle and polymer properties to obtain substantially improved material performance. Although earlier research on nanocomposites has remarkably enhanced our understanding of PNCs, less explored phenomena such as individual and collective chain dynamics and thermodynamically-driven wetting and dispersion phenomena, currently pose significant challenges to the applicability of PNCs in next-generation technologies. The focus of this project is to combine x-ray/neutron scattering with spectroscopy and simulations to understand the hierarchy of structures and dynamics and design advanced PNCs with controlled material properties.

Publications:

(* indicates corresponding author, †indicates equal first authors)

•      “Probing Elastic and Viscous Properties of Phospholipid Bilayers Using Neutron Spin Echo Spectroscopy”, M. Nagao*, E. G. Kelley, R. Ashkar, R. Bradbury, and P. D. Butler, J. Phys. Chem. Lett., 2017. http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b01830
•      “Rapid Large-Scale Assembly and Pattern Transfer of One-Dimensional Gold Nanorod Superstructures”, *R. Ashkar, *M. J. A. Hore, X. Ye, B. Natarajan, N. J. Greybush, T. Lam, C. R. Kagan, C. B. Murray, ACS Appl. Mater. Interfaces. 2017.  http://pubs.acs.org/doi/abs/10.1021/acsami.7b06273
•       “A Computational Approach to Model Neutron Scattering Data from Lipid Bilayers”, *J. M. Carrillo, J. Katsaras, B. Sumpter, and *R. Ashkar, J. Chem. Theory Comput. 2017.  http://pubs.acs.org/doi/abs/10.1021/acs.jctc.6b00968
•       “Unlocking the secrets of cell membranes”, R. Ashkar, Editorial, ACM SIGCAS Computers and Society Newsletter 2016.  http://dl.acm.org/citation.cfm?id=2984072&CFID=818445393&CFTOKEN=94065971
•       “Multiscale metrologies for process optimization of carbon nanotube polymer composites”, B. Natarajan, N. Orloff, R. Ashkar, S. Doshi, K. Twedt, A. Krishnamurthy, C. Davis, A. M. Forster, E. Thostenson, J. Obrzut, R. Sharma, and J. A. Liddle*, Carbon 2016 http://www.sciencedirect.com/science/article/pii/S0008622316306005
•      “Graphene nanocomposites with high molecular weight poly(ε-caprolactone) grafts: Controlled synthesis and accelerated crystallization”, †Titash Mondal, †R. Ashkar, P. Butler, A. Bhowmick* and Ramanan Krishnamoorti*, ACS Macro Lett. 2016. http://pubs.acs.org/doi/abs/10.1021/acsmacrolett.5b00930
•      “Lightweight, flexible, high-performance carbon nanotube cables made by scalable flow coating”, Francesca Mirri, Nathan D. Orloff, R. Ashkar, A. Forster, C. Long, A. Bengio, A. Choi, Y. Luo, A. Hight Walker, P. Butler,  K. Migler, and M. Pasquali*, ACS Appl. Mater. Interfaces 2016. http://pubs.acs.org/doi/abs/10.1021/acsami.5b11600
•      “Wetting-dewetting and dispersion-aggregation transitions are distinct for polymer grafted nanoparticles in chemically dissimilar polymer matrix”, †T. B. Martin, † K. I. Mongcopa, R. Ashkar, P. Butler, R. Krishnamoorti*, and Arthi Jayaraman*, J. Am. Chem. Soc. 2015.  http://pubs.acs.org/doi/full/10.1021/jacs.5b05291
•      “Tuning membrane thickness fluctuations in model lipid bilayers”, R. Ashkar, Michihiro Nagao*, P. Butler, A. Woodka, M. K. Sen and T. Koga, Biophys. J. 2015. http://www.sciencedirect.com/science/article/pii/S0006349515005457
•       “Thermoresponsive PNIPAM coatings on nanostructured gratings for cell alignment and release”, †M. Zhernenkov*, †R. Ashkar*, H. Feng, O. Akintewe, N. D. Gallant, R. Toomey, J. F. Ankner, and R. Pynn, ACS Appl. Mater. Interfaces 2015. http://pubs.acs.org/doi/abs/10.1021/acsami.5b01453
•       “Kinetic polymer arrest in percolated SWNT networks”, R. Ashkar*, M. Abdulbaki, M. Tyagi, A. Faraone, P. Butler and R. Krishnamoorti*, ACS Macro Lett. 2014. http://pubs.acs.org/doi/abs/10.1021/mz500636s?journalCode=amlccd
•       “A new approach for probing matter in periodic nanoconfinements using neutron scattering”, R. Ashkar*, R. Pynn, R. Dalgliesh, N. Lavrick, and I. Kravchenko. J. Appl. Cryst. 2014. http://scripts.iucr.org/cgi-bin/paper?S1600576714013387
•       “Dynamical Theory: Application to spin echo resolved grazing incidence scattering from periodic structures”, R. Ashkar*, W.L. Schaich, V.O. de Haan, A.A. van Well, R. Dalgliesh, J. Plomp, R. Pynn*. J. Appl. Phys. 2011. http://dx.doi.org/10.1063/1.3661162    
•       “Comparison of dynamical theory and phase-object approximation on neutron scattering from periodic structures”, *R. Ashkar, V. de Haan, A.A. vanWell, R. Dalgliesh, J. Plomp, W.L. Schaich, and R. Pynn. J. Appl. Cryst. 2011. http://dx.doi.org/10.1107/S0021889811032730
•       “Dynamical theory calculations of spin echo resolved grazing-incidence scattering from a diffraction grating”, R. Ashkar*, P. Stonaha, A. L.Washington, V. R. Shah, M. R. Fitzsimmons, B. Maranville, C. F. Majkrzak, W. T. Lee, W. L. Schaich, and R. Pynn*, J. Appl. Cryst. 2010. http://dx.doi.org/10.1107/S0021889810010642    

Spring 2018

Foundation of Physics I (PHYS 2305)