Predicting octanol/water partition coefficient using solvation free energy and solvent-accessible surface area

The regression model for octanol/water partition coefficients ( K ow ), is founded with only two molecular descriptors available through quantum chemical calculations: solvation free energy (Δ G S ), and solvent accessible surface area (SASA). For the properties of 47 organic compounds from 17 types, the model gives a correction coefficient (adjusted for degrees of freedom) of 0 959 and a standard error of 0 277 log unit. It is a suitable way to predict the partition properties that are related to solute solvent interactions in the water phase.

Mechanism analysis of ions interaction in MgCl_2/LiCl solution and effect of lithium on ammonia precipitation products

Producing magnesium hydroxide is the basic way to utilize magnesium resources of natural brines. However, the effect of lithium on properties of product is always neglected. The interaction between ions in magnesium chloride solution containing lithium was illustrated based on the experimental results, and the effect of lithium on the crystallization of magnesium was clarified. The results of X-ray diffraction（XRD）, scanning election microscope（SEM）, Fourier transform infrared spectroscopy（FTIR）, thermogravimetry analysis（TGA） and laser particle size analysis indicate that the effect of lithium is not obvious on the crystal phase and morphology of the products. But the XRD relative intensity of（001） surface of magnesium hydroxide declines, the specific surface area reduces apparently and the additive mass of lithium affects the heat loss rates of precipitations obviously. Quantum chemical calculations on the interactional systems of Mg（H2O）2＋6 and Li（H2O）＋4 were performed using B3LYP/6-311 G basis set. The results show that when the distance of Mg2＋ and Li＋ is 7-10 , the interaction energy is high and the trend of solvation is strong, which would make hydroxide ions easier to combine with hydrogen ions in ammonia precipitation process. And the absolute value of solvation free energy reduces significantly in MgCl2 solution（1 mol/L） containing lithium ion.

Theoretical insights on the hydration of quinones as catholytes in aqueous redox flow batteries

Quinones have been widely studied as a potential catholyte in water-based redox flow batteries(RFBs)due to their ability to carry both electrons and protons in aqueous solutions.The wide variety of quinones and derivatives offers exciting opportunities to optimize the device performance while poses theoretical challenges to quantify their electrochemical behavior as required for molecular design.Computational screening of target quinones with high performance is far from satisfactory.While solvation of quinones affects their potential application in RFBs in terms of both electrochemical windows,stability,and charge transport,experimental data for the solvation structure and solvation free energies are rarely available if not incomplete.Besides,conventional thermodynamic models are mostly unreliable to estimate the properties of direct interest for electrochemical applications.Here,we analyze the hydration free energies of more than 1,400 quinones by combining the first-principles calculations and the classical density functional theory.In order to attain chemical insights and possible trends,special attention is placed on the effects of"backbones"and functional groups on the solvation behavior.The theoretical results provide a thermodynamic basis for the design,synthesis,and screening of high-performance catholytes for electrical energy storage.

HRW:Hybrid Residual and Weak Form Loss for Solving Elliptic Interface Problems with Neural Network

Deep learning techniques for solving elliptic interface problems have gained significant attentions.In this paper,we introduce a hybrid residual and weak form(HRW)loss aimed at mitigating the challenge of model training.HRW utilizes the functions residual loss and Ritz method in an adversary-system,which enhances the probability of jumping out of the local optimum even when the loss landscape comprises multiple soft constraints(regularization terms),thus improving model’s capability and robustness.For the problem with interface conditions,unlike existing methods that use the domain decomposition,we design a Pre-activated ResNet of ResNet(PRoR)network structure employing a single network to feed both coordinates and corresponding subdomain indicators,thus reduces the number of parameters.The effectiveness and improvements of the PRoR with HRW are verified on two-dimensional interface problems with regular or irregular interfaces.We then apply the PRoR with HRW to solve the size-modified Poisson-Boltzmann equation,an improved dielectric continuum model for predicting the electrostatic potentials in an ionic solvent by considering the steric effects.Our findings demonstrate that the PRoR with HRW accurately approximates solvation free-energies of three proteins with irregular interfaces,showing the competitive results compared to the ones obtained using the finite element method.

Identifying potential compounds from Bacopa monnieri(brahmi)against coxsackievirus A16 RdRp targeting HFM disease(tomato flu)

Hand,foot,and mouth disease(HFMD),primarily instigated by Coxsackievirus A16(CVA16),poses a serious health concern,necessitating effective therapeutic interventions.The RNA-dependent RNA polymerase(RdRp)of CVA16 emerges as a promising drug target for HFMD treatment.This study presents an in-silico pipeline for the identification of potential RdRp inhibitors against CVA16.A library of 91 natural compounds derived from Bacopa monnieri(brahmi)was virtually screened against the CVA16 RdRp.Here,Bacobitacin D emerged as a promising hit molecule,forming 8 hydrogen bonds including key catalytic site residues(Asp^(238)and Asp^(329))within the RdRp active site.Further,molecular dynamics(MD)simulations and MM/GBSA binding free energy calculations was applied on the top three hits that were selected based on exhaustive docking scores(≤-9.55 kcal/mol).Bacobitacin D exhibited sustainable stability,as evidenced by minimal deviation(RMSD=0.75±0.02 nm)during a 100 ns MD simulation.Importantly,Bacopaside IV exhibited the lowestΔGTOTAL binding free energy(-23.70 kcal/mol),while Bacobitacin D displayed a comparableΔGTOTAL of19.14 kcal/mol.Structural interpretation of the most populated cluster derived from MD simulations showed direct interactions of Bacobitacin D with pivotal catalytic residues,including Asp^(238)and Ser^(289).This comprehensive study confirmed Bacobitacin D as a potent inhibitor of CVA16 RdRp,offering a potential avenue for therapeutic intervention against HFMD.Experimental validation is required to confirm the inhibitory action of Bacobitacin D against HFMD.