Publications

(* corresponding author, † equal authors, underline: Postdoc/research associate, Graduate student, Undergraduate student in the Ashkar Lab)

2024

“Neutron spin echo shows pHLIP is capable of retarding membrane thickness fluctuations”, H.L. Scott, V. Burns-Casamayor, A.C. Dixson, R.F. Standaert, C.B. Stanley, L.-R. Stingaciu, J.-M.Y. Carrillo, B.G. Sumpter, J. Katsaras, W. Qiang, F.A. Heberle, B. Mertz, R. Ashkar*, F.N. Barrera*, Biochim. Biophys. Acta (BBA) – Biomembranes (2024).

2023

“The Effects of Molecular and Nanoscopic Additives on Phospholipid Membranes”, †T. Kumarage, †N.B. Morris, and R. Ashkar*, Front. Phys., Soft Matter Physics (2023). Invited Review

“Synthesis and Characterization of Stimuli-Responsive Polymer Brushes in Nanofluidic Channels”, H. Rahmaninejad, A.J. Parnell, W.-L. Chen, N. Duzen, T. Sexton, G. Dunderdale, J.F. Ankner, W. Bras, C.K. Ober*, A.J. Ryan*, and R. Ashkar*, ACS Appl. Mater. Interfaces (2023). doi.org/10.1021/acsami.3c12744;

“Solution Structure and Scaling Laws of Cylindrical and Tapered Bottlebrush Polymers”, M. Alaboalirat, S. J. Scannelli, H. Rahmaninejad, J.-M. Carrillo. C. Do, J.B. Matson*, and R. Ashkar*, Macromolecules (2023). doi.org/10.1021/acs.macromol.3c01412;

“Biophysics of Membrane Stiffening by Cholesterol and Phosphatidylinositol 4,5-bisphosphate (PIP2)”, F.T. Doole, T. Kumarage, R. Ashkar*, M.F. Brown*, Invited Chapter in the book titled Cholesterol and PI(4,5)P2 in Vital Biological Functions, edited by Avia Rosenhouse-Dantsker (Springer 2023). doi.org/10.1007/978-3-031-21547-6_2;

“Neutron Scattering Studies of Nanoscale Polymer-Based Coatings”, H. Rahmaninejad and R. Ashkar*, Invited Chapter in the book titled Polymer-Based Nanoscale Materials for Surface Coatings, edited by Sabu Thomas and Jesiya Susan George (Elsevier 2023). doi.org/10.1016/B978-0-32-390778-1.00024-4;

“Cinematic reflectometry using QIKR, the quite intense kinetics reflectometer”, J.F. Ankner*, R. Ashkar, J.F. Browning, …, E.B. Watkins, and D. Wilson, Rev. Sci. Instrum. (2023). doi.org/10.1063/5.0122279;

2022

“Cholesterol Stiffening of Lipid Membranes“, F.T. Doole, T. Kumarage, R. Ashkar*, M.F. Brown*, J. Membr. Biol. (2022). Topical Review. doi.org/10.1007/s00232-022-00263-9;

“Molecular Simulations and NMR Reveal How Lipid Fluctuations Affect Membrane Mechanics“, M. Doktorova*, G. Khelashvili, R. Ashkar, and M.F. Brown*, Biophys. J. (2023). doi.org/10.1016/j.bpj.2022.12.007;

“EXPANSE: A time-of-flight EXPanded Angle Neutron Spin Echo spectrometer at the Second Target Station of the Spallation Neutron Source“, C. Do*, R. Ashkar, C. Boone, …, D. Wilson, Y Z, Rev. Sci. Inst. (2022). doi.org/10.1063/5.0089349;

“Comparison of Bulk- vs Layer-by-Layer-Cured Stimuli-Responsive PNIPAM–Alginate Hydrogel Dynamic Viscoelastic Property Response via Embedded Sensors“, Y. Liu, K. Bethel, M. Singh, J. Zhang, R. Ashkar, E.M. Davis, B.N. Johnson*, ACS Appl. Polym. Mater. (2022). doi.org/10.1021/acsapm.2c00634;

“Molecular mechanisms of spontaneous curvature and softening in complex lipid bilayer mixtures”, H.J. Lessen, K.C. Sapp, A.H. Beaven, R. Ashkar, and A.J. Sodt*. Biophys. J. (2022). doi.org/10.1016/j.bpj.2022.07.036;

“Cholesterol stiffening of lipid membranes and drug interactions: Insights from neutron spin echo and deuterium NMR spectroscopy”, †S. Gupta, †F.T. Doole, T. Kumarage, M. Doktorova, G. Khelashvili, R. Ashkar*, and M.F. Brown*, Invited Chapter in the book titled Cholesterol, edited by Alex Dopico and Anna Bukiya (Elsevier 2022).

2021

“The dynamic face of lipid membranes”, S. Gupta and R. Ashkar*, Invited Review in the 2021 Soft Matter Emerging Investigators Themed Collection, Soft Matter (2021). Back Cover doi.org/10.1039/D1SM00646K;

“Neutron spin echo spectroscopy as a unique probe for lipid membrane dynamics and membrane-protein interactions”, †T. Kumarage, †J. Nguyen, and R. Ashkar*, Invited Paper in the Special Issue titled: “Neutron scattering in the biological sciences: Techniques and applications” J. Vis. Exp. (2021) doi: 10.3791/62396;

“Biomembrane structure and material properties studied with neutron scattering”, J. Kinnun*, H.L. Scott*, R. Ashkar*, and J. Katsaras*, Front. Chem. (2021). Invited Review doi.org/10.3389/fchem.2021.642851;

2020

“Scaling relationships for the elastic moduli and viscosity of mixed lipid membranes”, E.G. Kelley*, P. Butler, R. Ashkar, R. Bradbury, and M. Nagao, Proc. Natl. Acad. Sci. (2020) doi.org/10.1073/pnas.2008789117

“How cholesterol stiffens unsaturated lipid membranes”, S. Chakraborty, M. Doktorova, T.R. Molugu, F.A. Heberle, H.L. Scott, B. Dzikovski, M. Nagao, L.-R. Stingaciu, R.F. Standaert, F. Barrera, J. Katsaras, G. Khelashvili, M.F. Brown*, and R. Ashkar*, Proc. Natl. Acad. Sci. (2020) doi.org/10.1073/pnas.2004807117;

“Selective Dynamics in Polymeric Materials: Insights from Quasi-Elastic Neutron Scattering Spectroscopy”, R. Ashkar*, J. Appl. Phys. (2020). Invited Tutorial & Featured Article doi.org/10.1063/1.5144243;

“Profile retrieval of a buried periodic structure using spin echo grazing incidence neutron scattering”, R. Ashkar*, R.M. Dalgliesh, R. Pynn, A.D.F. Dunbar, R.A.L. Jones, and A.J. Parnell*, Appl. Phys. Lett. (2020). doi.org/10.1063/1.5140616;

2019

“The Influence of Curvature on Domain Distribution in Binary Mixture Membranes”, W. Li, J. M. Carrillo*, J. Katsaras, B. Sumpter, R. Ashkar*, and R. Kumar*, Soft Matter (2019). Back Cover doi.org/10.1039/C9SM01262A;

2018

“Neutron scattering in the biological sciences: Progress and prospects”, R. Ashkar, H.Z. Bilheux, H. Bordallo, R. Briber, D.J.E. Callaway, X. Cheng, . . . and J.C. Smith*, Acta Cryst. D (2018). Lead article doi.org/10.1107/S2059798318017503;

“Quantification of carbon nanotube liquid crystal morphology via neutron scattering”, †F. Mirri, †R. Ashkar, V. Jamali, L. Liberman, R.A. Pinnick, P. van der Schoot, Y. Talmon, P.D. Butler, and M. Pasquali*, Macromolecules (2018) doi.org/10.1021/acs.macromol.8b01017;

“Conformational change and suppression of the Θ-temperature for solutions of polymer-grafted nanoparticles”, †K.I. S. Mongcopa, †R. Poling-Skutvik, R. Ashkar, P. Butler, and R. Krishnamoorti*, Soft Matter (2018) doi.org/10.1039/C8SM00929E;

“Flexible approach to vibrational sum-frequency generation using shaped near-infrared light”, A. Chowdhury, F. Liu, B. Watson, R. Ashkar, J. Katsaras, C. Collier, D. Lutterman, Y.Z. Ma, T.R. Calhoun*, B. Doughty*, Optics Lett. (2018) doi.org/10.1364/OL.43.002038;

“Grating-based holographic diffraction methods for X-rays and neutrons: Phase object approximation and dynamical theory“, H. Feng, R. Ashkar, N. Steinke, R. Dalgliesh, N.V. Lavrik, I.I. Kravchenko, R. Pynn. J. Appl. Cryst. (2018) doi.org/10.1107/S1600576717016867;

Previous Publications by R. Ashkar