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Full-Text Articles in Physics
A Comparison Of New Methods For Generating Energy-Minimizing Configurations Of Patchy Particles, Eric Jankowski, Sharon C. Glotzer
A Comparison Of New Methods For Generating Energy-Minimizing Configurations Of Patchy Particles, Eric Jankowski, Sharon C. Glotzer
Eric Jankowski
Increasingly complex particles are pushing the limits of traditional simulation techniques used to study self-assembly. In this work, we test the use of a learning-augmented Monte Carlo method for predicting low energy configurations of patchy particles shaped like “Tetris®” pieces. We extend this method to compare it against Monte Carlo simulations with cluster moves and introduce a new algorithm—bottom-up building block assembly—for quickly generating ordered configurations of particles with a hierarchy of interaction energies.
Charge Transfer Assisted By Collective H-Bonding Network Dynamics, Omar F. Mohammed, Christina M. Othon, Oh-Hoon Kwon, Ahmed H. Zewail
Charge Transfer Assisted By Collective H-Bonding Network Dynamics, Omar F. Mohammed, Christina M. Othon, Oh-Hoon Kwon, Ahmed H. Zewail
Christina M Othon
Although there have been numerous studies of solvation, the role of solvent specific and collective interactions, especially for charge-transfer processes, remains difficult to unravel. Here, we report, using femtosecond fluorescence up-conversion and steady-state spectroscopic measurements, studies of well-designed single-sited formylperylene (FPe) in binary solvents. One of the solvents (methanol, MOH) can selectively hydrogen (H) bond to the carbonyl (C=O) site, while the other (acetonitrile, ACN) cannot, but both have similar polarity ( for MOH and for ACN). The results reveal that ultrafast charge transfer from the perylene unit to the carbonyl group of FPe is facilitated by site-specific H-bonding interactions …
Solvation In Protein (Un)Folding: Effect Of Local And Bulk Dynamics In The Melittin Tetramer-Monomer Transition, Christina M. Othon, Oh-Hoon Kwon, Milo M. Lin, Ahmed H. Zewail
Solvation In Protein (Un)Folding: Effect Of Local And Bulk Dynamics In The Melittin Tetramer-Monomer Transition, Christina M. Othon, Oh-Hoon Kwon, Milo M. Lin, Ahmed H. Zewail
Christina M Othon
Protein structural integrity and flexibility are intimately tied to solvation. Here we examine the effect that changes in bulk and local solvent properties have on protein structure and stability. We observe the change in solvation of an unfolding of the protein model, melittin, in the presence of a denaturant, trifluoroethanol. The peptide system displays a well defined transition in that the tetramer unfolds without disrupting the secondary or tertiary structure. In the absence of local structural perturbation, we are able to reveal exclusively the role of solvation dynamics in protein structure stabilization and the (un)folding pathway. A sudden retardation in …
Periodic And Dynamic 3-D Gold Nanoparticle− Dna Network Structures For Surface-Enhanced Raman Spectroscopy-Based Quantification, Kyuwan Lee
Kyuwan Lee
The enhancement factor of gold nanoparticles linked by DNA in a three-dimensional (3-D) network structure was evaluated as 1.12 × 107 and shown to be greater than a two-dimensional (2-D) array by a factor of 10, possibly due to the dimensional expansion of resonance and periodicity of the so formed structures. Uniform and higher level of enhancement was possible from these DNA linked gold nanoparticle networks because of the matching of the resonant condition and the excitation wavelength (785 nm) to enable dynamic quantification of analytes by surface-enhanced Raman spectroscopy (SERS). The structure was first validated by obtaining a SERS …
Appearance Of A Fractional Stokes-Einstein Relation In Water And A Structural Interpretation Of Its Onset, L. Xu, F. Mallamace, Z. Yan, Francis W. Starr, S. V. Buldyrev, H. E. Stanley
Appearance Of A Fractional Stokes-Einstein Relation In Water And A Structural Interpretation Of Its Onset, L. Xu, F. Mallamace, Z. Yan, Francis W. Starr, S. V. Buldyrev, H. E. Stanley
Francis Starr
The Stokes–Einstein relation has long been regarded as one of the hallmarks of transport in liquids. It predicts that the self-diffusion constant D is proportional to (τ/T)−1, where τ is the structural relaxation time and T is the temperature. Here, we present experimental data on water confirming that, below a crossover temperature T× ≈ 290 K, the Stokes– Einstein relation is replaced by a ‘fractional’ Stokes–Einstein relation D ∼ (τ/T)−ζ with ζ ≈ 3/5 (refs 1–6). We interpret the microscopic origin of this crossover by analysing the OH- stretch region of the Fourier transform infrared spectrum over a temperature range …
Review Of Biocd Physics And Technology, David D. Nolte
Review Of Biocd Physics And Technology, David D. Nolte
David D Nolte
Spinning biodisks have advantages that make them attractive for specialized biochip applications. The two main classes of spinning biodisks are microfluidic disks and bio-optical compact disks BioCD. Microfluidic biodisks take advantage of noninertial pumping for lab-on-a-chip devices using noninertial valves and switches under centrifugal and Coriolis forces to distribute fluids about the disks. BioCDs use spinning-disk interferometry, under the condition of common-path phase quadrature, to perform interferometric label-free detection of molecular recognition and binding. The optical detection of bound molecules on a disk is facilitated by rapid spinning that enables high-speed repetitive sampling to eliminate 1/ f noise through common-mode …