Nickel(II) complexes of 3-acetyl-4,5-dihydro-1,2,4-triazole hydrazones

3-Acetyl-1,2,4-triazole hydrazones (3b,c) and methylhydrazone (4d) were prepared by reacting triazoles (1b–d) with an excess of hydrazines at room temperature. Square planar nickel(II) complexes (8b,c) of (3b,c) were obtained from their reaction with Ni(OAc)₂ in a 2:1 mol ratio in EtOH at room temperature. The spectral data suggest structures (8b,c) for the obtained complexes, which result from ring opening of the triazole ring followed by recyclization to give the 5-arylhydrazono-2,3-dihydro-4H-1,2,4-triazine ligand (7b,c). The reaction of triazole methylhydrazone (4d) with Ni(OAc)₂ in EtOH resulted, however, in the formation of the starting triazole (1d). All new compounds were characterized by elemental analysis, i.r., ¹H-n.m.r. ¹³C-n.m.r. and hrms.     

Reliability of Speaking and Maximum Voice Range Measures in Screening for Dysphonia

Speech range profile (SRP) is a graphical display of frequency-intensity occurring interactions during functional speech activity. Few studies have suggested the potential clinical applications of SRP. However, these studies are limited to qualitative case comparisons and vocally healthy participants. The present study aimed to examine the effects of voice disorders on speaking and maximum voice ranges in a group of vocally untrained women. It also aimed to examine whether voice limit measures derived from SRP were as sensitive as those derived from voice range profile (VRP) in distinguishing dysphonic from healthy voices. Ninety dysphonic women with laryngeal pathologies and 35 women with normal voices, who served as controls, participated in this study. Each subject recorded a VRP for her physiological vocal limits. In addition, each subject read aloud the "North Wind and the Sun" passage to record SRP. All the recordings were captured and analyzed by Soundswell's computerized real-time phonetogram Phog 1.0 (Hitech Development AB, T?by, Sweden). The SRPs and the VRPs were compared between the two groups of subjects. Univariate analysis results demonstrated that individual SRP measures were less sensitive than the corresponding VRP measures in discriminating dysphonic from normal voices. However, stepwise logistic regression analyses revealed that the combination of only two SRP measures was almost as effective as a combination of three VRP measures in predicting the presence of dysphonia (overall prediction accuracy: 93.6% for SRP vs 96.0% for VRP). These results suggest that in a busy clinic where quick voice screening results are desirable, SRP can be an acceptable alternate procedure to VRP.     

Dye-sensitized solar cells concocted with dyes extracted from fresh and dried leaves of Henna using different solvents

Optical and Quantum Electronics - Nowadays, world is moving from conventional energy sources to non-conventional energy sources like solar energy, wind power, hydropower and those energy sources...     

High-Throughput GC-FID Method for the Determination of Residual Solvents in Early-Phase Drug Discovery Samples

Chromatographia - In drug discovery environment, determination of residual solvents is indispensable and requires rapid analysis covering a maximum number of commonly used solvents especially with...     

Optimization of solvents for effective isolation of colchicines from Gloriosa superba L. seeds

To meet the strong demand of colchicine an attempt is made to optimize the solvent system for isolation of colchicine. Gloriosa superba dried seed powder was extracted by using different solvents. Maximum yield of colchicine was obtained when extracted with water and alcohol in the ratio of 50 : 50.     

Synthesis and Chelating Properties of Polystyrene Supported Schiff Base (N,N′-disalicylidenepropylenetriamine) Resin Toward Some Divalent Metal Ions

A new polystyrene-supported Schiff base resin, N,N-bis(salicylidenepropylenetriamine)- aminomethyl polystyrene, has been synthesized through a reaction between the commercially available 4-chloromethyl polystyrene polymer and the Schiff base, N,N′-disalicylidenepropylenetriamine. The chelation behavior of this resin toward the divalent metal ions Cu^{2 +}, Ni^{2 +}, Zn^{2 +}, and Pb^{2 +} in aqueous solutions was investigated. Batch equilibration experiments were carried out as a function of contact time, pH, amount of metal-ion, polymer mass, and temperature. The amount of metal-ion uptake of the polymers was determined by using atomic absorption spectrometry (AAS). Results of the study revealed that the resin exhibited higher capacities and a more pronounced adsorption toward Cu^{2 +} and that the metal-ion uptake follows the order: Cu^{2 +} > Zn ^{2 +} > Ni^{2 +} > Pb²⁺. The adsorption and binding capacity of the resin toward the various metal ions investigated are discussed.     

Gas chromatography/trace analysis of derivatized azelaic acid as a stability marker

Azelaic acid, a naturally occurring saturated dicarboxylic acid, is found in many topical formulations for its various medical benefits or as a byproduct of the oxidative decomposition of unsaturated fatty acids. The poor volatility of azelaic acid hinders its applicability in GC analysis. Therefore, azelaic acid was derivatized by methylation and silylation procedures to enhance its volatility for GC analysis. Accordingly, dimethyl azelate (DMA) and di(trimethylsilyl) azelate were synthesized and characterized by GC–MS. Subsequently, a GC with flame ionization detection method was developed and validated to analyze trace amounts of azelaic acid in some marketed skin creams. Unlike DMA, di(trimethylsilyl) azelate was chemically unstable and degraded within few hours. Nonane was used as a stable internal standard. Variability due to derivatization and extraction was controlled by a standard addition procedure. DMA analysis was linear in a wide concentration range (100 ng/mL to 100 mg/mL). Moreover, the method was accurate (96.4–103.4%) and precise with inter‐ and intraday variability <2.0% and LOQ and LOD of 100 and 10 ng/mL, respectively.     

Green synthesis of zinc oxide nanoflowers using Hypericum triquetrifolium extract: characterization,antibacterial activity and cytotoxicity against lung cancer A549 cells

Zinc oxide nanoparticles have attracted significant interest in recent years due to their unique multifunctional chemical and physical properties along with their biological activities. This study demonstrated for the first time the biogenetic synthesis of zinc oxide nanoparticles by utilization of the methanolic extract of Hypericum triquetrifolium (HT). The obtained nanoparticles (HT-ZnO) were characterized by ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The shape of the resulted nanoparticles is fusiform nanoflowers with an average hydrodynamic size of 275.46 ± 0.20 nm and a zeta potential of −8.23 ± 0.26 mV. SEM micrographs revealed that HT-ZnO nanoflowers have a multi-process structure in which one of the processes is large and the others have similar smaller dimensions. The synthesized nanoflowers have an average length of 312.28 ± 78.93 nm and the tip of its processes has a width of 48.69 ± 9.71 nm. The antimicrobial activity of HT-ZnO nanoflowers was performed using microbroth dilution format. It showed a bactericidal mode of action against Gram-positive Staphylococcus aureus and Enterococcus faecalis with MIC/MBC values of 20 μg/mL and 5 μg/mL, respectively. MTT assay had revealed that HT-ZnO nanoflowers caused a dose-dependent decline in the viability of A549 adenocarcinomic human alveolar basal epithelial cells with an IC₅₀ value of 20.45 μg/mL. The effect of HT-ZnO nanoflowers on the migration and colony formation abilities against the same cells was evaluated as well. In conclusion, zinc oxide nanoflowers were successfully synthesized using methanolic extract of H. triquetrifolium. The resulting particles showed a bactericidal effect against Gram-positiveS. aureus and E. faecalis and a cytotoxic activity against A549 cells.