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Temperature dependence of atomic vibrations in mono-layer graphene

Allen, C.S. (author), Liberti, E. (author), Kim, J.S. (author), Xu, Q. (author), Fan, Y. (author), He, K. (author), Robertson, A.W. (author), Zandbergen, H.W. (author), Warner, J.H. (author), Kirkland, A.I. (author)

We have measured the mean square amplitude of both in- and out-of-plane lattice vibrations for mono-layer graphene at temperatures ranging from ?100 K to 1300?K. The amplitude of lattice vibrations was calculated from data extracted from selected area electron diffraction patterns recorded across a known temperature range with over 80...

journal article 2015

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TUT7 controls the fate of precursor microRNAs by using three different uridylation mechanisms

Kim, B. (author), Ha, M. (author), Loeff, L. (author), Chang, H. (author), Simanshu, D.K. (author), Li, S. (author), Fareh, M. (author), Patel, D.J. (author), Joo, C. (author), Kim, V.N. (author)

Terminal uridylyl transferases (TUTs) function as integral regulators of microRNA (miRNA) biogenesis. Using biochemistry, single-molecule, and deep sequencing techniques, we here investigate the mechanism by which human TUT7 (also known as ZCCHC6) recognizes and uridylates precursor miRNAs (pre-miRNAs) in the absence of Lin28. We find that the...

journal article 2015

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Distinct mechanisms regulating mechanical force-induced Ca2+ signals at the plasma membrane and the ER in human MSCs

Kim, T.J. (author), Joo, C. (author), Seong, J. (author), Vafabakhsh, R. (author), Botvinick, E.L. (author), Berns, M.W. (author), Palmer, A.E. (author), Wang, N. (author), Ha, T. (author), Jakobsson, E. (author), Sun, J. (author), Wang, Y. (author)

It is unclear that how subcellular organelles respond to external mechanical stimuli. Here, we investigated the molecular mechanisms by which mechanical force regulates Ca2+ signaling at endoplasmic reticulum (ER) in human mesenchymal stem cells. Without extracellular Ca2+, ER Ca2+ release is the source of intracellular Ca2+ oscillations induced...

journal article 2015

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Dynamic Growth and Shrinkage Govern the pH Dependence of RecA Filament Stability

Kim, S.H. (author), Park, J. (author), Joo, C. (author), Kim, D. (author), Ha, T. (author)

RecA proteins form a long stable filament on a single-stranded DNA and catalyze strand exchange reaction. The stability of RecA filament changes dramatically with pH, yet its detailed mechanism is not known. Here, using a single molecule assay, we determined the binding and dissociation rates of RecA monomers at the filament ends at various pH....

journal article 2015

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Molecular mechanism of sequence-dependent stability of RecA filament

Kim, S.H. (author), Joo, C. (author), Ha, T. (author), Kim, D. (author)

A is a DNA-dependent ATPase and mediates homologous recombination by first forming a filament on a single-stranded (ss) DNA. RecA binds preferentially to TGG repeat sequence, which resembles the recombination hot spot Chi (5'-GCTGGTGG-3') and is the most frequent pattern (GTG) of the codon usage in Escherichia coli. Because of the highly dynamic...

journal article 2013

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Phase anomalies in Bessel-Gauss beams

Kim, M.S. (author), Scharf, T. (author), Da Costa Assafrao, A. (author), Rockstuhl, C. (author), Pereira, S.F. (author), Urbach, H.P. (author), Herzig, H.P. (author)

Bessel-Gauss beams are known as non-diffracting beams. They can be obtained by focusing an annularly shaped collimated laser beam. Here, we report for the first time on the direct measurement of the phase evolution of such beams by relying on longitudinal-differential interferometry. We found that the characteristics of Bessel-Gauss beams cause...

journal article 2012

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Submicron hollow spot generation by solid immersion lens and structured illumination

Kim, M.S. (author), Assafrao, A.C. (author), Scharf, T. (author), Wachters, A.J.H. (author), Pereira, S.F. (author), Urbach, H.P. (author), Brun, M. (author), Olivier, S. (author), Nicoletti, S. (author), Herzig, H.P. (author)

We report on the experimental and numerical demonstration of immersed submicron-size hollow focused spots, generated by structuring the polarization state of an incident light beam impinging on a micro-size solid immersion lens (?-SIL) made of SiO2. Such structured focal spots are characterized by a doughnut-shaped intensity distribution, whose...

journal article 2012

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Evidence of the Griffiths phase in multiferroic BiMnO3 and BiFe0.5Mn0.5O3 films

Prokhorov, V.G. (author), Kaminsky, G.G. (author), Kim, J.M. (author), Yoo, Y.J. (author), Lee, Y.P. (author), Svetchnikov, V.L. (author), Levchenko, G.G. (author), Nikolaenko, Y.M. (author), Khokhlov, V.A. (author)

Microstructure and magnetic properties of BiMnO3 and BiFe0.5Mn0.5O3 films, prepared by rf magnetron sputtering on LaAlO3 (001) single-crystalline substrate, are investigated. The selected-area electron diffraction analysis allows us to identify the crystal structure of the BiMnO3 film as orthorhombic, while the BiFe0.5Mn0.5O3 film has a...

journal article 2012

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Effect of a nanoparticle on the optical properties of a photonic crystal cavity: Theory and experiment

Van der Sar, T. (author), Hagemeier, J. (author), Pfaff, W. (author), Heeres, E. (author), Thon, S. (author), Kim, H. (author), Petroff, P. (author), Oosterkamp, T. (author), Bouwmeester, D. (author), Hanson, R. (author)

Single quantum emitters can be coupled to photonic crystal (PC) cavities by placing their host nanoparticles into the cavity field. We describe fabrication, characterization, and tuning of gallium-phosphide PC cavities that resonate in the visible, and simulations and measurements of the effect of a nanoparticle on the optical properties of...

journal article 2012

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Interplay between real and pseudomagnetic field in graphene with strain

Kim, K.J. (author), Blanter, Y.M. (author), Ahn, K.H. (author)

We investigate electric and magnetic properties of graphene with rotationally symmetric strain. The strain generates a large pseudomagnetic field with alternating sign in space, which forms a strongly confined quantum dot connected to six chiral channels. The orbital magnetism, degeneracy, and channel opening can be understood from the interplay...

journal article 2011

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Deterministic nanoassembly of a coupled quantum emitter–photonic crystal cavity system

Van der Sar, T. (author), Hagemeier, J. (author), Pfaff, W. (author), Heeres, E.C. (author), Thon, S.M. (author), Kim, H. (author), Petroff, P.M. (author), Oosterkamp, T.H. (author), Bouwmeester, D. (author), Hanson, R. (author)

Controlling the interaction of a single quantum emitter with its environment is a key challenge in quantum optics. Here, we demonstrate deterministic coupling of single nitrogen-vacancy (NV) centers to high-quality photonic crystal cavities. We preselect single NV centers and position their 50-nm-sized host nanocrystals into the mode maximum of...

journal article 2011

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Origin of an enhanced colossal magnetoresistance effect in epitaxial Nd0.52Sr0.48MnO3 thin films

Prokhorov, V.G. (author), Kaminsky, G.G. (author), Kim, J.M. (author), Eom, T.W. (author), Park, J.S. (author), Lee, Y.P. (author), Svetchnikov, V.L. (author), Levtchenko, G.G. (author), Nikolaenko, Y.M. (author), Khokhlov, V.A. (author)

Nd0.52Sr0.48MnO3 films of various thicknesses have been prepared by dc magnetron sputtering on single crystal LaAlO3 (001) substrates. Reducing the film thickness leads to a significant suppression of ferromagnetic (FM) ordering and the Curie point falls below the antiferromagnetic (AFM) transition temperature. When this occurs, a huge rise of...

journal article 2011

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Evidence of non-Dzyaloshinskii–Moriya ferromagnetism in epitaxial BiFeO3 films

Prokhorov, V.G. (author), Kaminsky, G.G. (author), Kim, J.M. (author), Eom, T.W. (author), Park, J.S. (author), Lee, Y.P. (author), Svetchnikov, V.L. (author), Levtchenko, G.G. (author), Nikolaenko, Y.M. (author), Khokhlov, V.A. (author)

X-ray diffraction analysis and high-resolution electron microscopy of BiFeO3 films prepared by dc magnetron sputtering on single-crystal LaAlO3 (001) substrates reveal that the films have a highly c-oriented orthorhombic crystalline structure. The magnetic properties of the BiFeO3 films are typical of ensembles of interacting superparamagnetic...

journal article 2011

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Two-dimensional growth, anisotropic polaron transport, and magnetic phase segregation in epitaxial Nd0.52Sr0.48MnO3 films

Prokhorov, V.G. (author), Kaminsky, G.G. (author), Kim, J.M. (author), Eom, T.W. (author), Park, J.S. (author), Lee, Y.P. (author), Svetchnikov, V.L. (author), Levtchenko, G.G. (author), Paschenko, A.V. (author), Medvedev, Y.V. (author), Nikolaenko, Y.M. (author), Bukin, G.V. (author), Khokhlov, V.A. (author)

Nd0.52Sr0.48MnO3 films have been fabricated by dc magnetron sputtering on single-crystal LaAlO3 (001) and SrTiO3 (011) substrates with additional annealing to relax the lattice strain. Although the Nd0.52Sr0.48MnO3 films were deposited simultaneously on different substrates at the same deposition rate, they differ in thickness by a factor of ? ....

journal article 2011

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The Role of Coherency Strains on Phase Stability in LixFePO4: Needle Crystallites Minimize Coherency Strain and Overpotential

Van der Ven, A. (author), Garikipati, K. (author), Kim, S. (author), Wagemaker, M. (author)

We investigate the role of coherency strains on the thermodynamics of two-phase coexistence during Li (de)intercalation of LixFePO4. We explicitly account for the anisotropy of the elastic moduli and analytically derive coupled chemical and mechanical equilibrium criteria for two-phase morphologies observed experimentally. Coherent two-phase...

journal article 2009

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Terahertz Near-Field Vectorial Imaging of Subwavelength Apertures and Aperture Arrays

Knab, J.R. (author), Adam, A.J.L. (author), Nagel, M. (author), Shaner, E. (author), Seo, M.A. (author), Kim, D.S. (author), Planken, P.C.M. (author)

We present measurements of the complete terahertz (THz) electric near-field distribution, Ex, Ey and Ez, in both the time- and frequency-domains, for subwavelength apertures and subsections of subwavelength aperture arrays. Measuring the individual components of the THz near-field with subwavelength spatial resolution, as they emerge from these...

journal article 2009

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Diversity of Archaea and detection of crenarchaeotal amoA genes in the rivers Rhine and Têt

Herfort, L. (author), Kim, J.H. (author), Coolen, M.J.L. (author), Abbas, B. (author), Schouten, S. (author), Herndl, G.J. (author), Sinninghe Damste, J.S. (author)

Pelagic archaeal phylogenetic diversity and the potential for crenarchaeotal nitrification of Group 1.1a were determined in the rivers Rhine and Têt by 16S rRNA sequencing, catalyzed reported deposition-fluorescence in situ hybridization (CARD–FISH) and quantification of 16S rRNA and functional genes. Euryarchaeota were, for the first time,...

journal article 2009

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Advanced terahertz electric near-field measurements at sub-wavelength diameter metallic apertures: Erratum

Adam, A.J.L. (author), Brok, J.M. (author), Seo, M.A. (author), Ahn, K.J. (author), Kim, D.S. (author), Kang, J.H. (author), Park, Q.H. (author), Nagel, M. (author), Planken, P.C.M. (author)

An erratum is presented to correct an error in the discussion section of [Opt. Express. 16, 7407-7417 (2008)] and to add a relevant reference on earlier work.

journal article 2008

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Near field imaging of terahertz focusing onto rectangular apertures

Seo, M.A. (author), Adam, A.J.L. (author), Kang, J.H. (author), Lee, J.W. (author), Ahn, K.J. (author), Park, Q.H. (author), Planken, P.C.M. (author), Kim, D.S. (author)

We performed terahertz near-field experiments on single rectangular holes with various lengths grown on an electro-optic crystal substrate with ?/100 resolution. We find that the near-field amplitude becomes proportionally larger as the rectangle becomes narrower, strongly suggesting that a constant energy passes through even for a very narrow...

journal article 2008

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Microstructures and the corresponding magnetic properties of half-doped Nd0.5Sr0.5MnO3 films

Prokhorov, V.G. (author), Hyun, Y.H. (author), Park, J.S. (author), Kim, J.B. (author), Kim, G.H. (author), Lee, Y.S. (author), Lee, Y.P. (author), Svetchnikov, V.L. (author)

The microstructural and magnetic properties of amorphous, nanoclustered, and self-organized bilayer Nd0.5Sr0.5MnO3 films, prepared by rf magnetron sputtering, are investigated. The amorphous film was found to be a typical paramagnet with free motion of the individual Mn spins, and the magnetic properties are well described on the basis of the...

journal article 2008