Machine Learning Seams of Conical Intersection: A Characteristic Polynomial Approach.

The machine learning of potential energy surfaces (PESs) has undergone rapid progress in recent years. The vast majority of this work, however, has been focused on the learning of ground state PESs. To reliably extend machine learning protocols to excited state PESs, the occurrence of seams of conical intersections between adiabatic electronic states must be correctly accounted for.

Isotretinoin Exposure and Risk of Inflammatory Bowel Disease: A Systematic Review with Meta-Analysis and Trial Sequential Analysis.

Background: Cases of inflammatory bowel disease (IBD) following isotretinoin use have been reported previously, but whether isotretinoin exposure is associated with IBD has been unclear.

Objective: The aim was to evaluate whether isotretinoin use is associated with IBD.

Methods: We performed a systematic review and searched MEDLINE, Embase, and CENTRAL databases from inception to January 27, 2023 for relevant case-control and cohort studies.

85% internal quantum efficiency of 280-nm AlGaN multiple quantum wells by defect engineering.

In this study, high internal-quantum-efficiency (IQE) AlGaN multiple quantum wells (MQWs) were successfully demonstrated on low-defect-density AlN templates with nano-patterned sapphire substrates. These templates consisted of AlN structures with 0∼30 periods superlattices (SLs) by alternating high (100) and low (25) V/III ratios under a low growth temperature (1130 °C). Compared to conventional high crystal-quality AlN epilayers achieved at temperatures ≥1300 °C, lower thermal budget can reduce the production cost and wafer warpage.

Effect of non-vacuum thermal annealing on high indium content InGaN films deposited by pulsed laser deposition.

InGaN films with 33% and 60% indium contents were deposited by pulsed laser deposition (PLD) at a low growth temperature of 300 °C. The films were then annealed at 500-800 °C in the non-vacuum furnace for 15 min with an addition of N(2) atmosphere. X-ray diffraction results indicate that the indium contents in these two films were raised to 41% and 63%, respectively, after annealing in furnace.

High thermal stability of high indium content InGaN films grown by pulsed laser deposition.

Thermal stability on the structural and optical properties of high indium content InGaN films grown using pulsed laser deposition (PLD) was investigated through long-duration and high-temperature annealing. X-ray diffraction and cathode- luminescence measurements of the 33% indium InGaN revealed no differences in the line-shape and peak position even after annealing at 800°C for 95 min; similar structural stability was found for the 60% samples after annealing for 75 min. The higher thermal stability is attributed to nanoscale InN domains with different orientations create mixed-polarity InGaN/InN interfaces, resulting in higher activation energies at interfaces and increasing the thermal stability of the material.

High indium content InGaN films grown by pulsed laser deposition using a dual-compositing target.

High indium compositions InGaN films were grown on sapphires using low temperature pulse laser deposition (PLD) with a dual-compositing target. This target was used to overcome the obstacle in the InGaN growth by PLD due to the difficulty of target preparation, and provided a co-deposition reaction, where InGaN grains generated from the indium and GaN vapors deposit on sapphire surface and then act as nucleation seeds to promote further InGaN growth. The effects of co-deposition on growth mechanisms, surface morphology, and electrical properties of films were thoroughly investigated and the results clearly show promise for the development of high indium InGaN films using PLD technique with dual-compositing targets.

Donnan potential of dilute colloidal dispersions: Monte Carlo simulations.

Donnan equilibrium between a salt-free colloidal dispersion and an electrolyte solution has been investigated by Monte Carlo simulations. The Donnan potential is directly calculated by considering two compartments separated by a semipermeable membrane. In order to understand the role played by colloid-ion interactions, the influences of colloidal characteristics, including particle size R, intrinsic particle charge Z, counterion valency z(c), and concentration c(p), on Donnan potential Psi(D) and effective charge Z(eff) are examined.

Osmotic pressure and virial coefficients of star and comb polymer solutions: dissipative particle dynamics.

The effects of macromolecular architecture on the osmotic pressure pi and virial coefficients (B(2) and B(3)) of star and comb polymers in good solvents are studied by dissipative particle dynamics simulations for both dilute and semiconcentrated regimes. The dependence of the osmotic pressure on polymer concentration is directly calculated by considering two reservoirs separated by a semipermeable, fictitious membrane. Our simulation results show that the ratios A(n+1) identical with B(n+1)/R(g)(3n) are essentially constant and A(2) and A(3) are arm number (f) dependent, where R(g) is zero-density radius of gyration.

Equilibrium sedimentation profile of dilute, salt-free charged colloids.

The sedimentation profile of a dilute colloidal solution follows the barometric distribution owing to the balance between gravitational force and thermal fluctuation. However, the electrostatic interactions may lead to significant deviation even in the low volume fraction limit (e.g.

A-B diblock copolymer micelles: effects of soluble-block length and component compatibility.

Micellization of a diblock copolymer in dilute solution is studied by dissipative particle dynamics. The influence of the compatibility between blocks A and B and the interaction between the insoluble block and solvent on aggregation number P and micellar core radius Rc are examined. The micelle size distribution is obtained, and it is quite polydisperse.

Effects of multivalent salt addition on effective charge of dilute colloidal solutions.

The effective charge Z* is often invoked to account for the accumulation of counterions near the colloid with intrinsic charge Z. Although the ion concentrations c(i) are not uniform in the solution due to the presence of the charged particle, their chemical potentials are uniform everywhere. Thus, on the basis of ion chemical potential, effective ion concentrations c(i)*, which can be experimentally measured by potentiometry, are defined with the pure salt solution as the reference state.

Effective charges of polyelectrolytes in a salt-free solution based on counterion chemical potential.

The phenomenon of counterion condensation around a flexible polyelectrolyte chain with N monomers is investigated by Monte Carlo simulations in terms of the degree of ionization alpha, which is proportional to the effective charge. It is operationally defined as the ratio of observed to intrinsic counterion concentration, alpha = co/ci. The observed counterion concentration in the dilute polyelectrolyte solution is equivalent to an electrolyte solution of concentration co with the same counterion chemical potential.

Characterization of natural chitosan membranes from the carapace of the soldier crab Mictyris brevidactylus and its application to immobilize glucose oxidase in amperometric flow-injection biosensing system.

This study investigated characteristics of a chitosan membrane from the carapace of the soldier crab Mictyris brevidactylus intended to construct an amperometric biosensor. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used in this study to characterize these chitosan membranes intended for constructing enzymatic biosensors. Chitosan membranes suffering various durations (>10 min) of deacetylation had small charge-transfer resistances (<7.

Counterion condensation and release in micellar solutions.

Counterion condensation and release in micellar solutions are investigated by direct measurement of counterion concentration with ion-selective electrode. Monte Carlo simulations based on the cell model are also performed to analyze the experimental results. The degree of counterion condensation is indicated by the concentration ratio of counterions in the bulk to the total ionic surfactant added, alpha< or =1.

Charge renormalization of charged spheres based on thermodynamic properties.

At strong electrostatic coupling, counterions are accumulated in the vicinity of the surface of the charged particle with intrinsic charge Z. In order to explain the behavior of highly charged particles, effective charge Z(*) is therefore invoked in the models based on Debye-Huckel approximation, such as the Derjaguin-Landau-Verwey-Overbeek potential. For a salt-free colloidal suspension, we perform Monte Carlo simulations to obtain various thermodynamic properties omega in a spherical Wigner-Seitz cell.

Use of chitosan membrane from the carapace of the soldier crab Mictyris brevidactylus for biosensor construction.

Glucose oxidase (EC 1.3.4.