Synthesis of Pyrano,Pyrido, Oxazino,and Spiro Pyrazole Derivatives and Their Antimicrobial Activity

Russian Journal of Organic Chemistry - Condensation of 5-methyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one with 4-hydroxybenzaldhyde in alcoholic sodium hydroxide yielded...     

Different stability‐indicating chromatographic methods for specific determination of paracetamol,dantrolene sodium,their toxic impurities and degradation products

A well‐known analgesic (paracetamol, PAR) and skeletal muscle relaxant [dantrolene sodium (DNS)] have been analyzed without interference from their toxic impurities and degradation products. The studied PAR impurities are the genotoxic and nephrotoxic p‐amino phenol (PAP) and the hepatotoxic and nephrotoxic chloroacetanilide, while 5‐(4‐nitrophenyl)‐2‐furaldehyde is reported to be a mutagenic and carcinogenic degradation product of DNS. The five studied components were determined and quantified by TLC–densitometric and RP‐HPLC methods. TLC–densitometry (method 1) used TLC silica gel and chloroform–ethyl acetate–acetic acid–triethylamine (7:3:0.5:0.05, by volume) as the mobile phase with UV scanning at 230 nm, while RP‐HPLC (method 2) was based on separation on a C₁₈ column using methanol–water (55:45, v/v pH 3 with aqueous formic acid) as mobile phase at 1 mL/min and detection at 230 nm. The developed methods were used for determination and quantification of the five studied components in different laboratory‐prepared mixtures. The were also applied for analysis of Dantrelax^® compound capsules where no interference among the studied components with each other or from excipients was observed. The methods were validated as per International Conference on Harmonization guidelines, and they compared favorably with the reported ones.     

New insights on hydrogen evolution at Au single crystal electrodes

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Determination of chlorzoxazone,diclofenac potassium,and chlorzoxazone toxic degradation product by different chromatographic methods

JPC – Journal of Planar Chromatography – Modern TLC - The presented study was intended to design two validated, simple, and precise chromatographic methods for the determination of...     

Environmentally weathered residues source diagnostic by high-molecular-weight polycyclic aromatic sulphur heterocycles

High-molecular-weight polycyclic aromatic sulphur heterocycles (HMPASH) were applied in a forensic chemical analysis to identify the source(s) of environmentally weathered residues polluting the beaches of the Mediterranean city of Alexandria, Egypt, and to assess their weathering trends. The HMPASH were investigated by Fourier transform ion cyclotron resonance mass spectrometry in residues and an Egyptian crude as a possible source oil. The dibenzothiophenes/naphthenodibenzothiophenes (DBE 9/DBE 10) parameter indicated that two studied residues were likely to have originated from Egyptian crude oils, whereas the third residue could have had a foreign source. The residues displayed different stages of weathering. HMPASH having double bond equivalent (DBE) 1–5 were more influenced by weathering processes than those having DBE 6–17, probably because they are aliphatic sulphides and not aromatic compounds.     

Lactate and pyruvate levels correlation with lactate dehydrogenase gene expression and glucose consumption in Tamoxifen-resistant MCF-7 cells using capillary electrophoresis with contactless conductivity detection (CE-C4D)

Breast cancer is the second leading cause of cancer death in women after lung cancer. The first-line treatment of metastatic breast cancer in premenopausal women relies on tamoxifen. The development of tamoxifen resistance is not fully understood. In this study, capillary electrophoresis with capacitively coupled contactless conductivity detector was developed to monitor the changes in lactate and pyruvate levels in supernatant media of three models of developed MCF-7 tamoxifen-resistant cells and correlate these metabolites changes with lactate dehydrogenase genes expression and glucose consumption. The electrophoretic separation was achieved under reversed electroosmotic flow conditions. The linear ranges were 0.15–5 and 0.01–1 mM with a correlation coefficient of 0.9966 and 0.9971 and the limits of detection were 0.01 and 0.02 μM for lactate and pyruvate, respectively. Inter- and intrarun accuracy were in the range of 96.88–105.94% with precision (CV, %) of ≤7.35%. The method was completely validated and the results were in agreement with those obtained using the lactate and glucose assay kits. The results revealed a significant increase in both lactate and pyruvate production in the three tamoxifen-resistant MCF-7 cells models compared to control cells. This increase was correlated with the increase of lactate dehydrogenase genes expression and the increase of glucose consumption.     

Cryptographic Algorithm Using Newton-Raphson Method and General Bischi-Naimzadah Duopoly System

Image encryption is an excellent method for the protection of image content. Most authors used the permutation-substitution model to encrypt/decrypt the image. Chaos-based image encryption methods are used in this model to shuffle the rows/columns and change the pixel values. In parallel, authors proposed permutation using non-chaotic methods and have displayed good results in comparison to chaos-based methods. In the current article, a new image encryption algorithm is designed using combination of Newton-Raphson’s method (non-chaotic) and general Bischi-Naimzadah duopoly system as a hyperchaotic two-dimensional map. The plain image is first shuffled by using Newton-Raphson’s method. Next, a secret matrix with the same size of the plain image is created using general Bischi-Naimzadah duopoly system. Finally, the XOR between the secret matrix and the shuffled image is calculated and then the cipher image is obtained. Several security experiments are executed to measure the efficiency of the proposed algorithm, such as key space analysis, correlation coefficients analysis, histogram analysis, entropy analysis, differential attacks analysis, key sensitivity analysis, robustness analysis, chosen plaintext attack analysis, computational analysis, and NIST statistical Tests. Compared to many recent algorithms, the proposed algorithm has good security efficiency.     

Cover Picture: A Microfluidic Approach to Chemically Driven Assembly of Colloidal Particles at Gas–Liquid Interfaces (Angew. Chem. Int. Ed. 29/2009)

A chemically mediated microfluidic approach to the generation of particle‐coated bubbles is reported by E. Kumacheva and co‐workers in their Communication on page 5300 ff. The approach employs rapid, controllable dissolution of CO₂ bubbles in a dispersion of carboxylated particles. Local increases in the acidity of the medium in the neighborhood of the bubbles lead to a change in the surface energy of the particles and their deposition on the gas–liquid interface.

     

Polycyclic aromatic sulfur heterocycles as information carriers in environmental studies

Polycyclic aromatic hydrocarbons (PAHs) play a huge role in environmental analytical chemistry, both as pollutants and as markers for many processes. On the other hand, polycyclic aromatic sulfur heterocycles (PASHs; heterocyclic compounds related to PAHs) have been studied far less intensely, but such studies may lead to a great deal of information not available through the study of PAHs. Here we discuss analytical aspects of PASHs in environmental matrices and their use as information carriers. Since PASHs accompany PAHs in sampling and work-up, it is not necessary to expend much extra analytical effort in order to analyze them. This work reviews how they can provide information on diverse processes such as petroleum, industrial and vehicular pollution, and sources of air and marine pollution.