Memory consolidation refers to a process by which labile newly formed memory traces are progressively strengthened into long term memories and become more resistant to interference. Recent work has revealed that spontaneous hippocampal activity during rest, commonly referred to as "offline" activity, plays a critical role in the process of memory consolidation. Hippocampal reactivation occurs during sharp-wave ripples (SWRs), which are events associated with highly synchronous neural firing in the hippocampus and modulation of neural activity in distributed brain regions.
View Article and Find Full Text PDFOn-site quantitative analysis of pesticide residues is crucial for monitoring environmental quality and ensuring food safety. Herein, we have developed a reliable hydrogel portable kit using NaYbF@NaYF: Yb, Tm upconversion nanoparticles (UCNPs) combined with MnO nanoflakes. This portable kit is integrated with a smartphone reader and Python-assisted analysis platform to enable sample-to-result analysis for chlorpyrifos.
View Article and Find Full Text PDFMonitoring organophosphorus pesticides is significant for food safety assessment. Herein, we developed upconversion nanoparticles (UCNPs)-based self-ratiometric fluorescent platform for the detection of chlorpyrifos. The UCNPs have the ability to confine the detection and reference functions in one nanoparticle.
View Article and Find Full Text PDFSimilar to the spontaneous formation of colonies of bacteria, flocks of birds, or schools of fish, "living crystals" can be formed by artificial self-propelled particles such as Janus colloids. Unlike usual solids, these "crystals" are far from thermodynamic equilibrium. They fluctuate in time forming a crystalline structure, breaking apart and re-forming again.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
April 2009
The structural properties of a binary colloidal quasi-one-dimensional system confined in a narrow channel are investigated through modified Monte Carlo simulations. Two species of particles with different magnetic moment interact through a repulsive dipole-dipole force are confined in a quasi-one-dimensional channel. The impact of three decisive parameters (the density of particles, the magnetic-moment ratio, and the fraction between the two species) on the transition from disordered phase to crystal-like phases and the transitions among the different mixed phases are summarized in a phase diagram.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
October 2007
Within the Monte Carlo formalism supplemented by the modified Newton-Raphson optimization technique, we investigated structural and dynamical properties of two-dimensional binary clusters confined in an external hard-wall potential. Two species of differently charged classical particles, interacting through the repulsive Coulomb force are confined in the cluster. Subtle changes in the energy landscape and the stable cluster configurations are investigated as a function of the total number of particles and the relative number of each of the two particle species.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
November 2004
The distortion due to a fixed point impurity with variable charge placed in the center of a classical harmonically confined two-dimensional (2D) large Coulomb cluster is studied. We find that the net topological charge (N(-)-N+ ) of the system is always equal to six independent of the position and charge of the impurity. In comparison with a 2D cluster without impurity charge, only the breathing mode remains unchanged.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
March 2004
The structural and dynamical properties of two-dimensional (2D) clusters of equally charged classical particles, which are confined in an external hard wall potential, are investigated through the Monte Carlo simulation technique. The ground-state configuration is investigated as a function of the interparticle interaction (Coulomb, dipole, logarithmic, and screened Coulomb). The excitation spectrum corresponding to the ground-state configuration of the system is discussed.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
February 2003
The configurational and melting properties of large two-dimensional (2D) clusters of charged classical particles interacting with each other via the Coulomb potential are investigated through the Monte Carlo simulation technique. The particles are confined by a harmonic potential. For a large number of particles in the cluster (N>150), the configuration is determined by two competing effects, namely, the fact that in the center a hexagonal lattice is formed, which is the groundstate for an infinite 2D system, and the confinement that imposes its circular symmetry on the outer edge.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
April 2002
Structural and static properties of a classical two-dimensional system consisting of a finite number of charged particles that are laterally confined by a parabolic potential are investigated by Monte Carlo simulations and the Newton optimization technique. This system is the classical analog of the well-known quantum dot problem. The energies and configurations of the ground and all metastable states are obtained.
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