From nickel oxalate dihydrate microcubes to NiS<Subscript>2</Subscript> nanocubes for high performance supercapacitors

In this study, NiS₂ nanocubes were successfully synthesized by a novel facile solvothermal method using NiC₂O₄·2H₂O microstructures and used as an electrode for high-performance supercapacitors. The electrochemical properties of the prepared NiS₂ electrode were studied using galvanostatic charge–discharge analysis, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) studies. Its maximum specific capacitance was 2077 F g^?1 at a constant current density of about 0.65 A g^?1. Further, the EIS results confirmed the pseudocapacitive nature of the NiS₂ electrode. The experimental results suggested that the NiS₂ electro-active material demonstrates excellent electrochemical performance with high specific capacitance, low resistance, and excellent cycling stability.     

Thermochemistry of the Reaction of Solvated Sodium Ion Clusters with Thymine in the Gas Phase: An Example of the Reaction in Microcosmic Environment

The thermochemistry of the reaction of the microsolvated Na⁺ such as [Na(H₂O) _n ; n?=?1?6]⁺, [Na(NH₃) _n ; n?=?1?6]⁺ and [Na(H₂O) _n (NH₃) _m ; n?+?m?=?2?6]⁺ with thymine (Thy), as an example of a reaction in the microcosmic environment, have been studied in this work, theoretically. It was found that the increase of the number of solvent molecules in the structure of microsolvated Na⁺ is accompanied by the decrease of the standard enthalpy (\(\Delta H_{r}^{^\circ }\)) and Gibbs free (\(\Delta G_{r}^{^\circ }\)) energies of the reaction (Thy?+?[Na(X) _n ]⁺→Thy-Na(X) _n ⁺ ; X?=?solvent molecule). Also, the calculations showed that the electronic intermolecular interaction (?E_int) between the Thy and microslovated Na⁺ decreased with the increase of solvent molecules. For the interaction of the [Na(H₂O) _n ; n?=?4, 5 and 6]⁺ ions with the Thy, there was the probability of forming of the hydrogen bond between water molecules in the structure of solvated Na⁺ and the Thy. The gas phase infrared (IR) spectra of the complexes of the microsolvated Na⁺ with the Thy for different values of n were calculated and compared with each other to follow the change in the frequency of the stretching vibration of the interaction path between the C=O group of the Thy and Na (O…Na) with n. Using the calculated values of \(\Delta G_{r}^{^\circ }\) of the reactions, the mole fractions of the complexes of microsolvated Na⁺ ions with the Thy were calculated at different humidity.     

The effect of curvature of Li-doped polycyclic hydrocarbon on its interaction energy with H<Subscript>2</Subscript> and H<Subscript>2</Subscript>O: DF-SAPT (DFT) calculation

In this work, the interaction of three Li⁺-doped polycyclic hydrocarbons (Li⁺-DPH) with H₂ and H₂O was calculated to investigate the effect of curvature of substrate on the interaction energy (E_int). For this purpose, the E_int and its decomposed energy components (electrostatic (E_elec), exchange (E_exch), induction (E_ind), and dispersion energy (E_disp)) were calculated using DF-SAPT (DFT) methodology for the selected systems (Li⁺-(3,3) carbon nanotube (Li⁺-CNT33), Li⁺-(6,6) carbon nanotube (Li⁺-CNT66), and Li⁺-graphene). According to the results, E_int does not change significantly with curvature for the interaction between both H₂ and H₂O gases and the selected Li⁺-DPH. Since the variation of the E_int with the curvature of Li⁺-DPH is not significant, the selection of a planar Li⁺-DPH is a trustworthy model to develop a general force field for describing the interaction between a Li⁺-DPH and adsorbed gases. The results reveal that, in the case of the H₂, the components E_elect, E_exch, E_ind, and E_disp have shown a decreasing trend with Li⁺-DPH’s curvature decrement. However, for the H₂O, E_elect, E_exch, and E_ind decrease from the Li⁺-CNT33 to the Li⁺-CNT66 while they increase from the Li⁺-CNT66 to the Li⁺-graphene. In this case, the E_disp increases with a decrease of the curvature of Li⁺-DPH. Finally, it can be seen that although the variation of the E_int with the curvature of Li⁺-DPH is not significant, the variation trend of the interaction energy components and the amount of variation depend on the gas molecule and in some cases are not negligible.     

Adsorption of sodium dodecyl benzene sulfonate onto carbonate rock: Kinetics,equilibrium and mechanistic study

In this study, kinetics, equilibrium, and mechanisms of SDBS adsorption onto carbonate rock in presence/absence of alkaline/electrolyte, which is not well discussed in the available literature, is analyzed through batch experiments. Analysis of kinetic data showed that adsorption rate of SDBS onto carbonate is controlled by both boundary layer and intraparticle diffusion, also adsorption kinetics meets pseudo second-order model. The coefficient of kinetic model is a linear function of initial and equilibrium concentrations. The adsorption isotherm experiences four distinct regions, with a rising trend in the first regions until reaching to a maximum after which decreases slightly, as the fourth region, due to micellar exclusion. The prevailing mechanisms in other regions were also discussed. Presence of alkaline changes adsorption mechanisms, so that adsorption isotherm matches well with the Langmuir model, while presence of electrolyte does not change the adsorption mechanisms, but it lessens repulsion between surfactant heads which results in a slight reduction in amount of CMC. A new three-parameter equilibrium model is presented which considers all prevailing mechanisms, and matches properly with obtained experimental data, especially the decreasing trend of fourth region which is very difficult to predict along with other regions using a unique isotherm model.     

Catalyst-free synthesis of 1,2,4,5-tetrasubstituted imidazoles from arylamins,benzonitriles, arylglyoxals,and Meldrum’s acid

An efficient and catalyst-free for the synthesis of 1,2,4,5-tetrasubstituted imidazoles has been developed using a one-pot, two-step reaction of arylamins, benzonitriles, arylglyoxals, and Meldrum’s acid. All the products were obtained in good to excellent yields and their structures were established from their spectroscopic data.     

One-pot three-component reaction of ninhydrin, 1,3-dicarbonyl compounds,and primary amines to afford indeno[1,2-b]pyrrol-4(1H)-ones

Chemistry of Heterocyclic Compounds - A convenient one-pot three-component synthesis of indeno[1,2-b]pyrrol-4(1H)-ones has been developed. The reaction of ninhydrin, 1,3-dicarbonyl compounds, and...     

Multiple Protective Roles of Nanoliposome-Incorporated Baicalein against Alpha-Synuclein Aggregates

Nanoparticles are useful for increasing drug stability, solubility, and availability. The small molecule baicalein inhibits fibrillation, and detoxifies aggregates of α-synuclein (αSN) associated with Parkinson's disease (PD), but it suffers from instability, low solubility and consequent low availability. Here it is demonstrated that incorporation of baicalein into zwitterionic nanoliposomes (NLP-Ba) addresses these problems. NLP-Ba inhibits αSN fibril initiation, elongation, secondary nucleation, and also depolymerizes mature fibrils more effectively than free baicalein and prevents soluble αSN aggregates from seeding new fibrils. Importantly, NLP-Ba perturbs oligomers’ capacity to permeabilize the membrane. The interaction between NLP-Ba and αSN is confirmed by different biophysical techniques. This nanosystem crosses the blood-brain barrier in vitro and is effective against rotenone neurotoxicity in vivo. The effect of NLP-Ba on αSN fibrillation/cytotoxicity is attributed to a combination of free baicalein and empty NLPs. The results indicate a neuroprotective role for NLP-Ba in decreasing αSN pathogenicity in PD and highlight the use of nanoliposomes to mobilize poorly soluble hydrophobic drugs.     

Estimator learning automata for feature subset selection in high‐dimensional spaces,case study: Email spam detection

One of the difficult challenges facing data miners is that algorithm performance degrades if the feature space contains redundant or irrelevant features. Therefore, as a critical preprocess task, dimension reduction is used to build a smaller space containing valuable features. There are 2 different approaches for dimension reduction: feature extraction and feature selection, which itself is divided into wrapper and filter approaches. In high‐dimensional spaces, feature extraction and wrapper approaches are not applicable due to the time complexity. On the other hand, the filter approach suffers from inaccuracy. One main reason for this inaccuracy is that the subset's size is not determined considering specifications of the problem. In this paper, we propose ESS (estimator learning automaton‐based subset selection) as a new method for feature selection in high‐dimensional spaces. The innovation of ESS is that it combines wrapper and filter ideas and uses estimator learning automata to efficiently determine a feature subset that leads to a desirable tradeoff between the accuracy and efficiency of the learning algorithm. To find a qualified subset for a special processing algorithm that functions on an arbitrary dataset, ESS uses an automaton to score each candidate subset upon the scale of the subset and accuracy of the learning algorithm using it. In the end, the subset with the highest score is returned. We have used ESS for feature selection in the framework of spam detection, a text classification task for email as a pervasive communication medium. The results show achievement in reaching the goal stated above.     

Community-aware single-copy content forwarding in Mobile Social Network

Wireless Networks - One of the most challenging issues in Mobile Social Networks (MSNs) is to design a messages forwarding method that achieves high delivery and low communication overhead....