A discretized representation for Monte Carlo simulation of deformed semiflexible chains.

In this study, we present a novel orientation discretization approach based on the rhombic triacontahedron for Monte Carlo simulations of semiflexible polymer chains, aiming at enhancing structural analysis through rheo-small-angle scattering (rheo-SAS). Our approach provides a more accurate representation of the geometric features of semiflexible chains under deformation, surpassing the capabilities of traditional lattice structures. Validation against the Kratky-Porod chain system demonstrated superior consistency, underscoring its potential to significantly improve the precision of uncovering geometric details from rheo-SAS data.

Off-Lattice Markov Chain Monte Carlo Simulations of Mechanically Driven Polymers.

We develop off-lattice simulations of semiflexible polymer chains subjected to applied mechanical forces by using Markov Chain Monte Carlo. Our approach models the polymer as a chain of fixed length bonds, with configurations updated through adaptive nonlocal Monte Carlo moves. This proposed method enables precise calculation of a polymer's response to a wide range of mechanical forces, which traditional on-lattice models cannot achieve.

Viscoelastic relaxation and topological fluctuations in glass-forming liquids.

A method for characterizing the topological fluctuations in liquids is proposed. This approach exploits the concept of the weighted gyration tensor of a collection of particles and permits the definition of a local configurational unit (LCU). The first principal axis of the gyration tensor serves as the director of the LCU, which can be tracked and analyzed by molecular dynamics simulations.

Functional composites by programming entropy-driven nanosheet growth.

Nanomaterials must be systematically designed to be technologically viable. Driven by optimizing intermolecular interactions, current designs are too rigid to plug in new chemical functionalities and cannot mitigate condition differences during integration. Despite extensive optimization of building blocks and treatments, accessing nanostructures with the required feature sizes and chemistries is difficult.

CENTAUR-The small- and wide-angle neutron scattering diffractometer/spectrometer for the Second Target Station of the Spallation Neutron Source.

CENTAUR has been selected as one of the eight initial instruments to be built at the Second Target Station (STS) of the Spallation Neutron Source at Oak Ridge National Laboratory. It is a small-angle neutron scattering (SANS) and wide-angle neutron scattering (WANS) instrument with diffraction and spectroscopic capabilities. This instrument will maximally leverage the high brightness of the STS source, the state-of-the-art neutron optics, and a suite of detectors to deliver unprecedented capabilities that enable measurements over a wide range of length scales with excellent resolution, measurements on smaller samples, and time-resolved investigations of evolving structures.

[Dual-specificity Phosphatase 1 Suppresses Vascular Smooth Muscle Cell Calcification by Optical Atrophy 1-related Pathway].

Objective To investigate the effect of dual-specificity phosphatase 1/optical atrophy 1 (DUSP1/OPA1) signaling pathway on vascular smooth muscle cell (VSMC) calcification.Methods An model of VSMC calcification was induced by exposure to β-glycerophosphate and calcium chloride.VSMC calcification was assessed by Alizarin Red S staining and calcium content by ELISA.

SANS characterization of time dependent, slow molecular exchange in an SDS micellar system.

We have investigated the molecular exchange of sodium dodecyl sulfate (SDS) micelles in aqueous solution by time-resolved small angle neutron scattering (TR-SANS) measurements as a function of the surfactant and salt concentration. Starting with deuterated (d-SDS) and protonated (h-SDS) SDS micelles, surfactant exchange across the micelles leads to a randomized distribution of d-SDS and h-SDS within each micelle. By employing the contrast matching technique, we have studied this randomization process which is a direct measure of the molecular exchange of this system.

Ion Atmosphere of Wormlike Micelles Profiled by Contrast Variation Small-Angle Neutron Scattering.

Structural studies of wormlike micelles have so far mostly focused on the conformational properties of surfactant aggregates. The diffuse ionic atmosphere, which has a profound influence on various micellization phenomena such as thermodynamic stability and structural polymorphism, remains largely unexplored experimentally. In this report a strategy of contrast variation small-angle neutron scattering for this crucial structural study is outlined.

Small angle scattering of diblock copolymers profiled by machine learning.

We outline a machine learning strategy for quantitively determining the conformation of AB-type diblock copolymers with excluded volume effects using small angle scattering. Complemented by computer simulations, a correlation matrix connecting conformations of different copolymers according to their scattering features is established on the mathematical framework of a Gaussian process, a multivariate extension of the familiar univariate Gaussian distribution. We show that the relevant conformational characteristics of copolymers can be probabilistically inferred from their coherent scattering cross sections without any restriction imposed by model assumptions.

Diffusion characteristics of water molecules in a lamellar structure formed by triblock copolymers.

The distribution and diffusion of water molecules are playing important roles in determining self-assembly and transport properties of polymeric systems. Small-angle neutron scattering (SANS) experiments and molecular dynamics (MD) simulation have been applied to understand the distribution of water molecules and their dynamics in the lamellar membrane formed by Pluronic L62 block copolymers. Penetration of water molecules into the polyethylene oxide (PEO) layers of the membranes has been estimated using scattering length density (SLD) profiles obtained from SANS measurements, which agree well with the molecular distribution observed from MD simulations.

Scaling of Shear Rheology of Concentrated Charged Colloidal Suspensions across Glass Transition.

Electrostatic interparticle interactions are a key component in controlling and designing the rheological characteristics of concentrated charged colloidal suspensions. Herein, we investigate electroviscous effects on shear rheology using highly charged silica particles. By fixing the volume fraction but varying the salinity, the system undergoes a glass transition as evidenced by the evolution of the yield stress and zero-shear viscosity.

Spatial correlations of entangled polymer dynamics.

The spatial correlations of entangled polymer dynamics are examined by molecular dynamics simulations and neutron spin-echo spectroscopy. Due to the soft nature of topological constraints, the initial spatial decays of intermediate scattering functions of entangled chains are, to the first approximation, surprisingly similar to those of an unentangled system in the functional forms. However, entanglements reveal themselves as a long tail in the reciprocal-space correlations, implying a weak but persistent dynamic localization in real space.

Spatiotemporal mapping of mesoscopic liquid dynamics.

The study of liquid dynamics at mesoscopic scales is still strewn with difficulty due to limitations in theory and experiment. Historically, significant attention has been given to the analysis of space-time correlation functions and their frequency-Fourier transforms at a few discrete wave numbers. The massive computing power afforded by modern high performance computing clusters and the advent of a wide-angle neutron spin-echo spectrometer, however, have unlocked a more intuitive and fruitful approach to this problem.

The Prostate Health Index aids multi-parametric MRI in diagnosing significant prostate cancer.

To evaluate the performance of the Prostate Health Index (PHI) in magnetic resonance imaging-transrectal ultrasound (MRI-TRUS) fusion prostate biopsy for the detection of clinically significant prostate cancer (csPCa). We prospectively enrolled 164 patients with at least one Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) ≥ 3 lesions who underwent MRI-TRUS fusion prostate biopsy. Of the PSA-derived biomarkers, the PHI had the best performance in predicting csPCa (AUC 0.

An exact inversion method for extracting orientation ordering by small-angle scattering.

We outline a nonparametric inversion strategy for determining the orientation distribution function (ODF) of sheared interacting rods using small-angle scattering techniques. With the presence of direct inter-rod interaction and fluid mechanical forces, the scattering spectra are no longer characterized by the azimuthal symmetry in the coordinates defined by the principal directions of simple shear conditions, which severely compounds the reconstruction of ODFs based on currently available methods developed for dilute systems. Using a real spherical harmonic expansion scheme, the real-space ODFs are uniquely determined from the anisotropic scattering spectra and their numerical accuracy is verified computationally.

Determining population densities in bimodal micellar solutions using contrast-variation small angle neutron scattering.

Self-assembly of amphiphilic polymers in water is of fundamental and practical importance. Significant amounts of free unimers and associated micellar aggregates often coexist over a wide range of phase regions. The thermodynamic and kinetic properties of the microphase separation are closely related to the relative population density of unimers and micelles.

Spatial correlation functions of paracrystals with radial symmetry.

We develop a phenomenological model to describe the structure of radially symmetric paracrystals whose long-range order are destroyed by propagation of particle fluctuations. General expressions are derived for the spatial correlation functions in one-, two-, and three-dimensional spaces. And the spatial correlation in paracrystals in reciprocal space is further discussed and clarified.

Magnetic Micro Sensors with Two Magnetic Field Effect Transistors Fabricated Using the Commercial Complementary Metal Oxide Semiconductor Process.

The fabrication and characterization of a magnetic micro sensor (MMS) with two magnetic field effect transistors (MAGFETs) based on the commercial complementary metal oxide semiconductor (CMOS) process are investigated. The magnetic micro sensor is a three-axis sensing type. The structure of the magnetic microsensor is composed of an x/y-MAGFET and a z-MAGFET.

Revealing the Influence of Salts on the Hydration Structure of Ionic SDS Micelles by Contrast-Variation Small-Angle Neutron Scattering.

The influence of lithium chloride (LiCl) on the hydration structure of anionic micelles of sodium dodecyl sulfate (SDS) in water was studied using the contrast-variation small-angle neutron scattering (SANS) technique. In the past, extensive computational studies have shown that the distribution of invasive water plays a critical role in the self-organization of SDS molecules and the stability of the assemblies. However, in past scattering studies the degree of the hydration level was not examined explicitly.

Complexation of Pluronic L62 (EO)-(PO)-(EO)/aerosol-OT (sodium bis(2-ethylhexyl)sulfosuccinate) in aqueous solutions investigated by small angle neutron scattering.

We investigate the phase behaviours of Pluronic L62 in aqueous solution in the presence of aerosol-OT (AOT) molecules by small angle neutron scattering (SANS). The presence of AOT significantly changes the micellization phenomenon of L62 micelles in aqueous solution, including their critical micelle temperature (CMT), global size, and asphericity. The origin of these observations is attributed to the complexation between the neutral L62 surfactants and the ionic AOT molecules, which additionally provides charge to the mixed micelles: we analyse the data and extract meaningful information using the Ornstein-Zernike integral formalism.

Melatonin Attenuates Calcium Deposition from Vascular Smooth Muscle Cells by Activating Mitochondrial Fusion and Mitophagy via an AMPK/OPA1 Signaling Pathway.

Mitochondrial fusion/mitophagy plays a role in cardiovascular calcification. Melatonin has been shown to protect against cardiovascular disease. This study sought to explore whether melatonin attenuates vascular calcification by regulating mitochondrial fusion/mitophagy via the AMP-activated protein kinase/optic atrophy 1 (AMPK/OPA1) signaling pathway.

Melatonin attenuates vascular calcification by inhibiting mitochondria fission via an AMPK/Drp1 signalling pathway.

Mitochondrial fission plays a role in cardiovascular calcification. Melatonin has previously been shown to protect against cardiovascular disease, so this study sought to explore whether it attenuates vascular calcification by regulating mitochondrial fission via the AMP-activated protein kinase/dynamin-related protein 1 (AMPK/Drp1) signalling pathway. The effects of melatonin on vascular calcification were investigated in vascular smooth muscle cells (VSMCs).