Preparation of a Novel Stationary Phase for Separation of Ethylbenzene Hydroperoxides

The novelty of this work is preparation of a special stationary phase for selective separation of hydroperoxides. This column can be used widely in the polymerization industries where a variety of initiators (mainly the hydroperoxides) are used. In this work, the ionic liquid-based silica particles were prepared and used as a novel stationary phase for separation of ethylbenzene hydroperoxides. The mobile phase of methanol/acetonitrile from 90:10 to 70:30 (v v^?1) was used to separate three isomers of ethylbenzene hydroperoxide. A satisfactory linearity was obtained from 1.0 to 110.0 mg mL^?1 (RSD <4.0 %). The stationary phase performed stably and produced reproducible results, highlighting its potential as a separation material.     

Synthesis of 3,3‐Disubstituted Oxindoles via a Three‐Component Condensation Reaction in H2O

An efficient method has been developed for the synthesis of a novel series of unsymmetrically 3,3‐disubstituted oxindoles in good‐to‐high yields by a one‐pot three‐component condensation reaction of 2‐hydroxynaphthalene‐1,4‐dione, an isatin, and a barbituric acid derivative, in H₂O, and with p‐toluenesulfonic acid as a catalyst, at 90°. The effects of solvent, temperature, and the amount of catalyst on the yield of the reaction have been investigated. Additionally, the influence of hydrophilicity and hydrophobicity of the reactants on the selectivity of products has been examined.     

Copolymers: efficient carriers for intelligent nanoparticulate drug targeting and gene therapy

Copolymers are among the most promising substances used in the preparation of drug/gene delivery systems. Different categories of copolymers, including block copolymers, graft copolymers, star copolymers and crosslinked copolymers, are of interest in drug delivery. A variety of nanostructures, including polymeric micelles, polymersomes and hydrogels, have been prepared from copolymers and tested successfully for their drug delivery potential. The most recent area of interest in this field is smart nanostructures, which benefit from the stimuli-responsive properties of copolymeric moieties to achieve novel targeted drug delivery systems. Different copolymer applications in drug/gene delivery using nanotechnology-based approaches with particular emphasis on smart nanoparticles are reviewed.     

DemocraticOP: A Democratic way of aggregating Bayesian network parameters

When there are several experts in a specific domain, each may believe in a different Bayesian network (BN) representation of the domain. In order to avoid having to work with several BNs, it is desirable to aggregate them into a single BN. One way of finding the aggregated BN is to start by finding the structure, and then find the parameters. In this paper, we focus on the second step, assuming that the structure has been found by some previous method.DemocraticOP is a new way of combining experts’ parameters in a model. The logic behind this approach is borrowed from the concept of democracy in the real world. We assume that there is a ground truth and that each expert represents a deviation from it - the goal is to try to find the ground truth based on the experts’ opinions. If the experts do not agree, then taking a simple average of their opinions (as occurs in classical aggregation functions such as LinOP and LogOP) is flawed. Instead, we believe it is better to identify similar opinions through clustering, and then apply averaging, or any other aggregation function, over the cluster with the highest number of members to obtain the aggregated parameters that are closest to the ground truth. In other words, respect the majority as is done in democratic societies instead of averaging over all experts’ parameters. The new approach is implemented and tested over several BNs with different numbers of variables and parameters, and with different numbers of experts. The results show that DemocraticOP outperforms two commonly used methods, LinOP and LogOP, in three key metrics: the average of absolute value of the difference between the true probability distribution and the one corresponding to the aggregated parameters, Kullback-Leibler divergence, and running time.     

Preparation and characterization of curcumin loaded gold/graphene oxide nanocomposite for potential breast cancer therapy

Research on Chemical Intermediates - Graphene oxide (GO) and gold/graphene oxide (Au/GO) nanocomposites were fabricated through a facile chemical route and their application as excellent...     

A concise study on dimedone: A versatile molecule in multi-component reactions,an outlook to the green reaction media

Dimedone is an interesting and versatile motif in most organic transformations. Its white to light yellow crystals have been utilized as substrate in wide range of organic reactions including multi-component transformations. The notability of dimedone is due to the acidic property of its methylene group which is in equilibrium with its tautomeric enol form. This phenomena permit dimedone to be utilized in several kinds of organic reactions eventuated to several organic molecules with potent pharmaceutical exclusivity. The mentioned nature of dimedone in addition with its low toxicity, easily accessibility and handling, moisture stability, and low cost make it interesting for organic chemists. During the last decades, perfuming an organic transformation based on green chemistry rules, is in demand. In this review the reactions of dimedone has been focused with an outlook to the solvent of media. Each section has been subdivided respect to the temperature of the transformations. All categorizations has been accomplished to the green media. The authors has also calculated the atom economy of each reaction on behalf of green chemistry concept.     

Electrosynthesis of cinnamic acid by electrocatalytic carboxylation of phenylacetylene in the presence of [NiII(Me4-NO2Bzo[15]tetraeneN4)] complex: An EC′CCC′C mechanism

A Ni(II) complex, [Ni^II(Me₄-NO₂Bzo[15]tetraeneN₄)], was used for electrocatalytic reduction of CO₂ in acetonitrile solvent. Then, the reduced form of CO₂ (CO₂^?) was used for selective carboxylation of phenylacetylene to produce cinnamic acid at room temperature. The potential of the process is significantly less negative in comparison with those reported earlier. Using sacrificial magnesium electrode as anode, controlled potential coulometry was carried out in an undivided glass cell. The spectral characterizations of FTIR, ¹H NMR, and ¹³C NMR demonstrated that cinnamic acid was the main product of the electrolysis. With respect to other catalysts, which have been previously reported in the literature, application of the Ni(II) complex in carboxylation of unsaturated compounds has three advantages: (1) the selectivity in the production of cinnamic acid; (2) more increase in the reduction current indicating that the carboxylation of phenylacetylene is fast; and (3) the potential shift of electrocatalytic reduction of CO₂ to less negative values showing that the Ni(II) complex has an excellent electrocatalytic activity for CO₂ reduction. According to the voltammetric and coulometric results, an EC′CCC′C mechanism was proposed for the electrocatalytic synthesis of cinnamic acid.     

Switchable Hydrophilicity Solvent-Based Homogenous Liquid–Liquid Microextraction (SHS-HLLME) Combined with GC-FID for the Quantification of Methadone and Tramadol

In this work, a new method based on homogeneous liquid-phase microextraction was developed for the determination of methadone and tramadol. Dipropylamine was used as extraction solvent with switchable hydrophilicity that can be miscible/immiscible upon the addition or removal of CO₂ as a reagent. The effects of operational parameters of the extraction such as volume of acceptor phase, volume of donor phase, pH of donor phase, and ionic strength of solution were investigated. Under optimal conditions, the preconcentration factors, the detection limits and the linearity of the method were achieved in the ranges of 135–138, 1.2 and 4–1000 µg L^?1, respectively. Finally, the proposed method has been successfully applied to the analysis of methadone and tramadol in urine samples. In urine sample, the preconcentration factors were 118 and 122 for methadone and tramadol, respectively. Additionally, calibration curves were found to be linear in the concentration range of 8–1000 µg L^?1 with the r² values better than 0.998. In addition, limits of detection and quantification were 2.4 and 8 µg L^?1, respectively, for both analytes.     

Simultaneous Spectrophotometric Determination of Aluminum and Iron in Micellar Media by Using the H‐Point Standard Addition Method

A very simple spectrophotometric method for simultaneous determination of aluminum(III) and iron(III) based on formation of their complexes with pyrocatechol violet (PCV) in micellar media, using the H‐point standard addition method (HPSAM), is described. In micellar media, the metal complexes of Al‐PCV and Fe‐PCV are formed very fast. Formation of both of the complexes was complete within 5 min at pH 8.5. The linear ranges for aluminum and iron were 0.05‐2.50 and 0.10‐4.00 μg mL^?1, respectively. The relative standard deviation (R.S.D.) for the simultaneous determination 0.40 μg mL^?1 of Al(III) and 0.20 μg mL^?1 of Fe(III) were 3.24% and 4.22%, respectively. Interference effects of common anions and cations were studied. The method was applied to simultaneous determination of Al(III) and Fe(III) in standard reference material and alloy samples.