Separation and analysis of triazine herbcide residues by capillary electrophoresis

Triazines are widely used in agriculture around the world as selective pre‐ and post‐emergence herbicides for the control of broad leaf and grassy weeds. With high toxicity and persistence, triazines can contaminate the environment and crops, so the development of rapid and sensitive methods for the determination of different triazines is necessary. Capillary electrophoresis comprises a group of techniques used to separate chemical mixtures. Analytical separation is based on different electrophoretic mobilities. This review focuses on the analysis of triazine herbicides with different modes of capillary electrophoresis, including capillary zone electrophoresis, micellar electrokinetic capillary electrophoresis, capillary electrochromatography and nonaqueous capillary electrophoresis. Determinations of triazines in various matrices such as surface water, groundwater, vegetables, soil and grains are emphasized. Copyright © 2014 John Wiley & Sons, Ltd.     

Statistical properties of the nonlinear negative binomial state

In this context, we introduce and investigate the properties of the nonlinear negative binomial state (the state which interpolates between the nonlinear coherent and the number states). Mainly we concentrate on the statistical properties for such state where we have discussed two different cases of squeezing phenomenon. The first case is the normal squeezing while the second is the amplitude squared squeezing, further the second order correlation function is also considered. Our discussion have been extended to include the quasi-probability distribution functions (W-Wigner and Q-functions). The quadrature distribution and the phase properties in Pegg-Barnett formalism besides the phase variances are considered. Examination of the resonance fluorescence against the present state is given (single atom and thermodynamic limit). It has been shown that the atomic inversion is sensitive to any variation in the nonlinear negative binomial number m.     

Synthesis of 8-cyano-1,4-dihydro-4-oxopyrrolo[1,2-a]pyrimidine-3-carboxylic acids as potential antimicrobial agents

The preparation of a variety of 8-cyano-1,4-dihydro-7-phenyl-4-oxopyrrolo[1,2-a]pyrimidine-3-carboxylicacids and 8-cyano-1,4-dihydro-7-p-fluorophenyl-4-oxopyrrolo[1,2-a]pyrimidine-3-carboxylic acids is described.     

High-performance liquid chromatographic analysis of vancomycin in plasma, bone, atrial appendage tissue and pericardial fluid

Solid-phase extraction coupled with reversed-phase high-performance liquid chromatography and UV detection was employed for the analysis of the antibiotic vancomycin in patient plasma, bone, atrial appendage, and pericardial fluid. Vancomycin was quantitated in samples from patients undergoing cardiac surgery. Calibrations were linear in the range 3-100 micrograms/ml vancomycin; the lower limit of detection was approximately 3 micrograms/ml in fluids with an absolute limit of detection in bone samples of 0.75 microgram per injection.     

Antileishmanial Activities of Medicinal Herbs and Phytochemicals In Vitro and In Vivo: An Update for the Years 2015 to 2021

Leishmaniasis is one of the most neglected tropical diseases that present areal public health problems worldwide. Chemotherapy has several limitations such as toxic side effects, high costs, frequent relapses, the development of resistance, and the requirement for long-term treatment. Effective vaccines or drugs to prevent or cure the disease are not available yet. Therefore, it is important to dissect antileishmanial molecules that present selective efficacy and tolerable safety. Several studies revealed the antileishmanial activity of medicinal plants. Several organic extracts/essential oils and isolated natural compounds have been tested for their antileishmanial activities. Therefore, the aim of this review is to update and summarize the investigations that have been undertaken on the antileishmanial activity of medicinal plants and natural compounds derived, rom plants from January 2015 to December 2021. In this review, 94 plant species distributed in 39 families have been identified with antileishmanial activities. The leaves were the most commonly used plant part (49.5%) followed by stem bark, root, and whole plant (21.9%, 6.6%, and 5.4%, respectively). Other plant parts contributed less (<5%). The activity was reported against amastigotes and/or promastigotes of different species (L. infantum, L. tropica, L. major, L. amazonensis, L. aethiopica, L. donovani, L. braziliensis, L. panamensis, L. guyanensis, and L. mexicana). Most studies (84.2%) were carried out in vitro, and the others (15.8%) were performed in vivo. The IC₅₀ values of 103 plant extracts determined in vitro were in a range of 0.88 µg/mL (polar fraction of dichloromethane extract of Boswellia serrata) to 98 µg/mL (petroleum ether extract of Murraya koenigii). Among the 15 plant extracts studied in vivo, the hydroalcoholic leaf extract of Solanum havanense reduced parasites by 93.6% in cutaneous leishmaniasis. Voacamine extracted from Tabernaemontana divaricata reduced hepatic parasitism by ≈30 times and splenic parasitism by ≈15 times in visceral leishmaniasis. Regarding cytotoxicity, 32.4% of the tested plant extracts against various Leishmania species have a selectivity index higher than 10. For isolated compounds, 49 natural compounds have been reported with anti-Leishmania activities against amastigotes and/or promastigotes of different species (L. infantum, L. major, L. amazonensis, L. donovani and L. braziliensis). The IC₅₀ values were in a range of 0.2 µg/mL (colchicoside against promastigotes of L. major) to 42.4 µg/mL (dehydrodieuginol against promastigotes of L. amazonensis). In conclusion, there are numerous medicinal plants and natural compounds with strong effects (IC₅₀ < 100 µg/mL) against different Leishmania species under in vitro and in vivo conditions with good selectivity indices (SI > 10). These plants and compounds may be promising sources for the development of new drugs against leishmaniasis and should be investigated in randomized clinical trials.     

Safranal Induces Vasorelaxation by Inhibiting Ca2+ Influx and Na+/Ca2+ Exchanger in Isolated Rat Aortic Rings

Introduction: Safranal, which endows saffron its unique aroma, causes vasodilatation and has a hypotensive effect in animal studies, but the mechanisms of these effects are unknown. In this study, we investigated the mechanisms of safranal vasodilation. Methods: Isolated rat endothelium-intact or -denuded aortic rings were precontracted with phenylephrine and then relaxed with safranal. To further assess the involvement of nitric oxide, prostaglandins, guanylate cyclase, and phospholipase A₂ in safranal-induced vasodilation, aortic rings were preincubated with L-NAME, indomethacin, methylene blue, or quinacrine, respectively, then precontracted with phenylephrine, and safranal concentration–response curves were established. To explore the effects of safranal on Ca²⁺ influx, phenylephrine and CaCl₂ concentration–response curves were established in the presence of safranal. Furthermore, the effect of safranal on aortic rings in the presence of ouabain, a Na⁺-K⁺ ATPase inhibitor, was studied to explore the contribution of Na⁺/Ca²⁺ exchanger to this vasodilation. Results: Safranal caused vasodilation in endothelium-intact and endothelium-denuded aortic rings. The vasodilation was not eliminated by pretreatment with L-NAME, indomethacin, methylene blue, or quinacrine, indicating the lack of a role for NO/cGMP. Safranal significantly inhibited the maximum contractions induced by phenylephrine, or by CaCl₂ in Ca²⁺-free depolarizing buffer. Safranal also relaxed contractions induced by ouabain, but pretreatment with safranal totally abolished the development of ouabain contractions. Discussion/Conclusion: Inhibition of Na⁺-K⁺ ATPase by ouabain leads to the accumulation of Na⁺ intracellularly, forcing the Na⁺/Ca²⁺ exchanger to work in reverse mode, thus causing a contraction. Inhibition of the development of this contraction by preincubation with safranal indicates that safranal inhibited the Na⁺/Ca²⁺ exchanger. We conclude that safranal vasodilation is mediated by the inhibition of calcium influx from extracellular space through L-type Ca²⁺ channels and by the inhibition of the Na⁺/Ca²⁺ exchanger.     

Numerical simulation of the performance of a novel parabolic solar receiver filled with nanofluid

Journal of Thermal Analysis and Calorimetry - The aim of this work is the energy analysis of a novel semicircle-shaped parabolic trough solar collector filled with the water–boehmite alumina...     

Synthesis of novel di-Se-containing thymidine and Se-DNAs for structure and function studies

The selenium derivatization of nucleic acids and nucleic acid-protein complexes has provided a powerful tool to solve phase problem in X-ray crystallography.Selenium atoms in the nucleotides can serve as fine scattering centers in crystal diffraction.Towards the synthesis of multiple selenium atom-containing nucleotides,which offers strong phasing power to facilitate crystal structure determination,we report here the synthesis of the thymidine analogue containing two Se atoms in one nucleobase.The novel Se-containing nucleoside and oligonucleotide DNAs were synthesized and found with the red-shifted UV spectrum and yellow color.Their unique properties are useful in phase determination,nucleic acid-based detection as well as spectroscopic studies of nucleic acids and nucleic acid-protein complexes.     

Theoretical investigation of the molecular structure,vibrational spectra,and molecular docking of tramadol using density functional theory

The optimized molecular structures, harmonic vibrational wavenumbers, and the corresponding vibrational assignments of (1S,2S)-tramadol and (1R,2R)-tramadol are computationally examined using the B3LYP density functional theory method together with the standard 6–311++G(d,p) and def2-TVZP basis sets. The optimized structures show that phenolic rings of both 1R,2R and 1S,2S tramadol adopt planar geometry, which are slightly distorted due to the substitution at the meta-position; and the six-membered cyclohexane adopts a slightly distorted chair conformation. The 1S,2S enantiomer is energetically more favorable than 1R,2R with the energy differences of 1.32 and 1.03 kcal/mol obtained at B3LYP/6–311++G(d,p) and B3LYP/Def2-TVZP levels, respectively. The analysis of the binding pocket in the silico molecular docking with the m-opioid receptor shows that it originated two clusters with the 1S,2S enantiomer and one cluster with the 1R,2R enantiomer of tramadol. The results point to a more stable complex of the m-opioid receptor with the 1R,2R enantiomer of tramadol.