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Publications

Control of the graphene-protein interface is required to preserve adsorbed protein function

Cornell Affiliated Author(s)
Author
T. Alava
J.A. Mann
Cécile Théodore
J.J. Benitez
W.R. Dichtel
J.M. Parpia
H.G. Craighead
Abstract

Graphene's suite of useful properties makes it of interest for use in biosensors. However, graphene interacts strongly with hydrophobic components of biomolecules, potentially altering their conformation and disrupting their biological activity. We have immobilized the protein Concanavalin A onto a self-assembled monolayer of multivalent tripodal molecules on single-layer graphene.

Journal
Analytical Chemistry
Date Published
Group (Lab)
Jeevak Parpia Group

Phenotypic model for early T-cell activation displaying sensitivity, specificity, and antagonism

Cornell Affiliated Author(s)
Author
P. François
G. Voisinne
E.D. Siggia
G. Altan-Bonnet
M. Vergassola
Abstract

Early T-cell activation is selected by evolution to discriminate a few foreign peptides rapidly from a vast excess of self-peptides, and it is unclear in quantitative terms how this is possible. We show that a generic proofreading cascade supplemented by a single negative feedback mediated by the Src homology 2 domain phosphatase-1 (SHP-1) accounts quantitatively for early T-cell activation, including the effects of antagonists.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Date Published
Funding Source
R01AI083408
Research Area

Resolving spin-orbit- and hyperfine-mediated electric dipole spin resonance in a quantum dot

Cornell Affiliated Author(s)
Author
M. Shafiei
K.C. Nowack
C. Reichl
W. Wegscheider
L.M.K. Vandersypen
Abstract

We investigate the electric manipulation of a single-electron spin in a single gate-defined quantum dot. We observe that so-far neglected differences between the hyperfine- and spin-orbit-mediated electric dipole spin resonance conditions have important consequences at high magnetic fields. In experiments using adiabatic rapid passage to invert the electron spin, we observe an unusually wide and asymmetric response as a function of the magnetic field. Simulations support the interpretation of the line shape in terms of four different resonance conditions.

Journal
Physical Review Letters
Date Published
Group (Lab)
Katja Nowack Group

Localization of viscous behavior and shear energy dissipation in articular cartilage under dynamic shear loading

Cornell Affiliated Author(s)
Author
M.R. Buckley
L.J. Bonassar
Itai Cohen
Abstract

Though remarkably robust, articular cartilage becomes susceptible to damage at high loading rates, particularly under shear. While several studies have measured the local static and steady-state shear properties of cartilage, it is the local viscoelastic properties that determine the tissue's ability to withstand physiological loading regimens. However, measuring local viscoelastic properties requires overcoming technical challenges that include resolving strain fields in both space and time and accurately calculating their phase offsets.

Journal
Journal of Biomechanical Engineering
Date Published
Funding Source
R21AR054867
Group (Lab)
Itai Cohen Group

Tightly bound trions in monolayer MoS 2

Cornell Affiliated Author(s)
Author
K.F. Mak
K. He
C. Lee
G.H. Lee
J. Hone
T.F. Heinz
J. Shan
Abstract

Two-dimensional (2D) atomic crystals, such as graphene and transition-metal dichalcogenides, have emerged as a new class of materials with remarkable physical properties. In contrast to graphene, monolayer MoS 2 is a non-centrosymmetric material with a direct energy gap. Strong photoluminescence, a current on/off ratio exceeding 10 8 in field-effect transistors, and efficient valley and spin control by optical helicity have recently been demonstrated in this material.

Journal
Nature Materials
Date Published
Funding Source
2011-0031629
DMR-1106172
DMR-0907477
0907477
1106172
1122594
DE-FG02-07ER15842
DE-SC0001085
Group (Lab)
Jie Shan Group
Kin Fai Mak Group

Multipoint correlators of conformal field theories: Implications for quantum critical transport

Cornell Affiliated Author(s)
Author
Debanjan Chowdhury
S. Raju
S. Sachdev
A. Singh
P. Strack
Abstract

We compute three-point correlators between the stress-energy tensor and the conserved currents of conformal field theories (CFTs) in 2+1 dimensions. We first compute the correlators in the large-flavor-number expansion of conformal gauge theories and then perform the computation using holography. In the holographic approach, the correlators are computed from an effective action on (3+1)-dimensional anti-de Sitter space (AdS4) and depend upon the coefficient γ of a four-derivative term in the action.

Journal
Physical Review B - Condensed Matter and Materials Physics
Date Published
Funding Source
1103860
Group (Lab)
Debanjan Chowdhury Group

Quasiparticle mass enhancement and temperature dependence of the electronic structure of ferromagnetic SrRuO3 thin films

Cornell Affiliated Author(s)
Author
D.E. Shai
C. Adamo
D.W. Shen
C.M. Brooks
J.W. Harter
E.J. Monkman
B. Burganov
D.G. Schlom
K.M. Shen
Abstract

We report high-resolution angle-resolved photoemission studies of epitaxial thin films of the correlated 4d transition metal oxide ferromagnet SrRuO 3. The Fermi surface in the ferromagnetic state consists of well-defined Landau quasiparticles exhibiting strong coupling to low-energy bosonic modes which contributes to the large effective masses observed by transport and thermodynamic measurements.

Journal
Physical Review Letters
Date Published
Group (Lab)
Kyle Shen Group

Growth and form of melanoma cell colonies

Cornell Affiliated Author(s)
Author
M.M. Baraldi
A.A. Alemi
J.P. Sethna
S. Caracciolo
C.A.M. La Porta
S. Zapperi
Abstract

We study the statistical properties of melanoma cell colonies grown in vitro by analyzing the results of crystal violet assays at different concentrations of initial plated cells and for different growth times. The distribution of colony sizes is described well by a continuous time branching process. To characterize the shape fluctuations of the colonies, we compute the distribution of eccentricities.

Journal
Journal of Statistical Mechanics: Theory and Experiment
Date Published
Funding Source
1066293
Research Area
Group (Lab)
James Sethna Group

Spin-orbit coupling in LaAlO3/SrTiO3 interfaces: Magnetism and orbital ordering

Cornell Affiliated Author(s)
Author
M.H. Fischer
S. Raghu
Eun-Ah Kim
Abstract

Rashba spin-orbit coupling together with electron correlations in the metallic interface between SrTiO3 and LaAlO3 can lead to an unusual combination of magnetic and orbital ordering. We consider such phenomena in the context of the recent observation of anisotropic magnetism. Firstly, we show that Rashba spin-orbit coupling can account for the observed magnetic anisotropy, assuming a correlation driven (Stoner type) instability toward ferromagnetism. Secondly, we investigate nematicity in the form of an orbital imbalance between dxz/dyz orbitals.

Journal
New Journal of Physics
Date Published
Group (Lab)