Dynamic Correlation Analysis between Stress-Strain Curve and Polymer Film Structure Using Persistent Homology.

Coarse-grained molecular dynamics (CG-MD) simulations and subsequent persistent homology (PH) analysis were performed to correlate the structure and stress-strain behavior of polymer films. During uniaxial tensile MD simulations, the first principal component of the persistence diagram obtained by principal component analysis (PCA) was in good agreement with the stress-strain curve. This indicates that PH + PCA can identify critical ring structures relevant to the dynamic changes in MD simulations without requiring any prior knowledge.

Comparison of Early Postoperative Stress Distribution around Short and Tapered Wedge Stems in Femurs with Different Femoral Marrow Cavity Geometries Using Finite Element Analysis.

Backgroud: In total hip arthroplasty (THA), the ideal stem length remains uncertain; different stem lengths are used in different cases or institutions. We aimed to compare the stress distributions of cementless tapered wedges and short stems in femurs with different femoral marrow geometries and determine the appropriate fit.

Methods: Finite element models were created and analyzed using HyperMesh and LS-DYNA R11.

Validation of a New Liquid Asymmetric-Electrode Plasma Optical Emission Spectroscopy (LAEP-OES) Method for Measurement of Total Mercury in Tuna.

Background: Mercury intake is caused by eating seafood, such as tuna and other predatory fish species. To reduce the health risks of mercury intake, it is necessary to continuously measure and monitor mercury concentrations at fish farms and markets. We have developed a compact system that can detect multiple heavy metals by liquid asymmetric-electrode plasma optical emission spectroscopy (LAEP-OES).

Predicting long-term trends in physical properties from short-term molecular dynamics simulations using long short-term memory.

This study proposes a novel long short-term memory (LSTM)-based model for predicting future physical properties based on partial data of molecular dynamics (MD) simulation. It extracts latent vectors from atomic coordinates of MD simulations using graph convolutional network, utilizes LSTM to learn temporal trends in latent vectors and make one-step-ahead predictions of physical properties through fully connected layers. Validating with MD simulations of Ni solid-liquid systems, the model achieved accurate one-step-ahead prediction for time variation of the potential energy during solidification and melting processes using residual connections.

Synthesis of 5-Amino-3(2)-furanones via -Methylation/Intramolecular Cyclization of γ-Sulfanylamides.

The -methylation/intramolecular cyclization of γ-sulfanylamide is depicted. Different methylating reagents were successfully employed for -methylation, depending on the substituent pattern of the amide in the starting γ-sulfanylamides; trimethyloxonium tetrafluoroborate was used for -aryl substituted γ-sulfanylamides, and the combination of methyl iodide and silver(I) tetrafluoroborate was used for -alkyl substituted γ-sulfanylamides. When the resulting sulfonium salt was treated with DBU, it smoothly underwent intramolecular cyclization to produce a series of -aryl, -alkyl, -dialkyl or -alkyl--aryl substituted 5-amino-3(2)-furanones in 55%-quantitative yields.