A Boosted Machine Learning Framework for the Improvement of Phase and Crystal Structure Prediction of High Entropy Alloys Using Thermodynamic and Configurational Parameters

The reason behind the remarkable properties of High-Entropy Alloys (HEAs) is rooted in the diverse phases and the crystal structures they contain. In the realm of material informatics, employing machine learning (ML) techniques to classify phases and crystal structures of HEAs has gained considerable significance. In this study, we assembled a new collection of 1345 HEAs with varying compositions to predict phases. Within this collection, there were 705 sets of data that were utilized to predict the crystal structures with the help of thermodynamics and electronic configuration. Our study introduces a methodical framework i.e., the Pearson correlation coefficient that helps in selecting the strongly co-related features to increase the prediction accuracy. This study employed five distinct boosting algorithms to predict phases and crystal structures, offering an enhanced guideline for improving the accuracy of these predictions. Among all these algorithms, XGBoost gives the highest accuracy of prediction (94.05%) for phases and LightGBM gives the highest accuracy of prediction of crystal structure of the phases (90.07%). The quantification of the influence exerted by parameters on the model's accuracy was conducted and a new approach was made to elucidate the contribution of individual parameters in the process of phase prediction and crystal structure prediction

The effect of steel composition on the Behaviour of inclusions during steelmaking

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Anharmonic, dynamic and functional level effects in far-infrared spectroscopy: Phenol derivatives

International audienceThe far-infrared (far-IR) spectra of phenol and four ortho-substituted phenol derivatives, including three deuterated analogs, are presented. These spectra, measured using the free electron laser FELIX, are used to compare the performance of Born-Oppenheimer Molecular Dynamics (BOMD) with several commonly used levels of static density functional theory in the far-IR region. The molecules studied here form intramolecular hydrogen bonds of different strengths (except phenol), display diverse degrees of flexibility, and the OH moieties of the molecules provide large amplitude, anharmonic OH torsional modes. Since several of the molecules contain two OH groups, strong anharmonic couplings can also be present. Moreover, the experimental far-IR spectra of phenol and saligenin show overtones and combination bands as proven by the measurements of their deuterated analogs. All these characteristics of the molecules enable us to test the performance of the applied levels of theory on different complicating factors. Briefly summarized, both the strength of the hydrogen bond and molecular rigidity do not significantly influence the agreement between theory and experiment. All applied theoretical methods have difficulties to consistently predict modes that include the anharmonic OH torsional motion, resulting in overestimated intensities and frequencies. Coupling between two OH functional groups provides an additional challenge for theories, as seen for catechol. The various employed theoretical methods are found to complement each other, showing good results for complex harmonic modes in the case of static B3LYP-D3, while improved results are observed for anharmonic modes, including the OH torsional modes and their couplings, in the case of BOMD. Additionally, BOMD calculates the relative intensities better than the other theories. VPT2 reproduces weak anharmonic modes well, but it overestimates shifts and intensities for strong anharmonic modes

Modulation of Protonation–Deprotonation Processes of 2‑(4′-Pyridyl)benzimidazole in Its Inclusion Complexes with Cyclodextrins

2-(4′-Pyridyl)­benzimidazole (4PBI) can exist in several states of protonation, having three basic nitrogen atoms. The equilibria involving these states, in ground as well as in excited states, are found to be affected significantly by cyclodextrins (CDs). The formation of inclusion complexes of this compound with all three varieties of cyclodextrins is observed to be more favorable at pH 9 than at pH 4, due to the predominance of the neutral form of dye at pH 9. The binding affinity of 4PBI to CDs is found to be governed by two factors: (i) the size of the host and (ii) the mode of insertion of 4PBI. We find that, for the host with a smaller cavity (α-CD), insertion of the dye with a pyridyl face is favored, whereas, for γ-CD, the preference is shifted toward the benzimidazole face of the dye. For β-CD, the binding affinity of the dye is maximum due to perfect cavity matching with the guest. A combination of steric factor and hydrogen bonding interaction is found to be responsible for modulation of the protonation–deprotonation equilibria of the guest molecule in the inclusion complex. Surprisingly, a protonated form is found to be promoted upon inclusion in cyclodextrins, under certain conditions. This is an unusual behavior and has been rationalized by prototropism involving the hydroxyl protons of cyclodextrin molecules

The molecular interaction of a copper chelate with human P-glycoprotein

One of the major reasons for multidrug resistance (MDR) in cancer is the overexpression of P-glycoprotein (P-gp, ABCB1), a drug efflux pump. A novel copper complex, namely, copper (II) N-(2-hydroxyacetophenone) glycinate (CuNG) previously synthesized and characterized by the authors had been tested in this study. In a cell-based assay system with human MDR1 cDNA overexpressed mouse fibroblast NIH MDR1-G185 cell line, we demonstrated that this metal complex can directly interact with this transporter. As CuNG increased cellular accumulation of doxorubicin in P-gp-expressing cells, we presumed that of CuNG may be potential to reverse P-gp-mediated drug resistance probably by lowering the P-gp expression at the protein as well as mRNA level. Interestingly, our studies on UIC2 (a conformation sensitive monoclonal antibody) binding assay indicated the direct interaction of CuNG with P-gp. However, CuNG did not compete for the substrate binding as photoaffinity labeling of P-gp with a substrate analog [125I] iodoarylazidoprazosin ([125I] IAAP) showed approximately twofold increase in [125I] IAAP binding in presence of CuNG. In vitro study showed that CuNG significantly stimulated P-gp-specific ATPase activity in isolated membrane preparations from NIH MDR1-G185 cells. This result further confirmed the CuNG–P-gp direct interaction. This study also demonstrated that CuNG has a drug interaction site different from verapamil-, vinblastine- and progesterone-binding sites on P-gp. Taken together, this is the first report of molecular interaction of any Schiff’s base metal chelate CuNG with human P-gp. This information may be useful to design more efficacious nontoxic metal-based drugs as MDR-reversing agents