Separation study of some heavy metal cations through a bulk liquid membrane containing 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane

Competitive permeation of seven metal cations from an aqueous source phase containing equimolar concentrations of Co2+, Fe3+, Cd2+, Cu2+, Zn2+, Ag+ and Pb2+ metal ions at pH 5 into an aqueous receiving phase at pH 3 through an organic phase facilitated by 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane (Kryptofix5) as a carrier was studied as bulk liquid membrane transport. The obtained results show that the carrier is highly selective for Ag+ cation and under the employed experimental conditions, it transports only this metal cation among the seven studied metal cations. The effects of various organic solvents on cation transport rates have been demonstrated. Among the organic solvents involving nitrobenzene (NB), chloroform (CHCl3), dichloromethane (DCM) and 1,2-dichloroethane (1,2-DCE) which were used as liquid membrane, the most transport rate was obtained for silver (I) cation in DCM. The sequence of transport rate for this cation in organic solvents was: DCM > CHCl3 > 1,2-DCE > NB. The competitive transport of these seven metal cations was also studied in CHCl3–NB and CHCl3–DCM binary solvents as membrane phase. The results show that the transport rate of Ag+ cation is sensitive to the solvent composition and a non-linear relationship was observed between the transport rate of Ag+ and the composition of these binary mixed non-aqueous solvents. The influence of the stearic acid, palmitic acid and oleic acid as surfactant in the membrane phase on the transport of the metal cations was also investigated

Mesoporous ZnCr₂O₄ Nanocatalyst with High Specific Surface Area for Facile Synthesis of Flavonoid Derivatives

ZnCr2O4 nanoparticles with a high specific surface area have been fabricated using a hydrothermal synthetic process and were used as an effective catalyst to synthesize flavonoid derivatives. The textural and structural properties of the spinel were studied by X-ray diffraction (XRD), Field Emission scanning electron microscope (FE-SEM), nitrogen sorption techniques, and Fourier transform infrared spectroscopy (FT-IR). XRD confirmed the formation of cubic Zinc Chromite spinel with a small crystallite size of 5.04 nm. While Transmission Electron Microscopy (TEM) illustrated the particle size of ∼8, 10, and 16 nm. Textural analysis by N2 sorption revealed a mesoporous system with a high specific surface of 215 m2/g for ZnCr2O4. Moreover, all desired flavonoids were obtained in high yields under solvent-free conditions with the aid of the ZnCr2O4 catalyst. Structures of all flavonoid derivatives were confirmed by 1H-NMR, 13C-NMR, FT-IR, and their melting points.</p

Aspirin administration from early pregnancy versus initiation after 11 weeks of gestation for prevention of pre-eclampsia in high-risk pregnant women: Study protocol for randomized controlled trial

Background: Pre-eclampsia (PE) is a multiorgan disorder that affects 2–5% of all pregnant women. Present recommendations for when to start aspirin in high-risk women are after 11 wk of gestation. Objective: We present a protocol to investigate the effectiveness of aspirin use from early pregnancy, which is a randomized controlled trial to assess whether prescribed low-dose aspirin from early pregnancy reduces the prevalence of early and late-onset PE. Additionally, to compare the effectiveness of aspirin administration before and after 11 wk in reducing the occurrence of PE? Materials and Methods: All pregnancies at risk of PE, according to demographic and midwifery history, who are referred to the Maternal-Fetal Clinic of Tehran University hospital, Tehran, Iran were invited to take part in the trial. The outcomes of pregnancy and newborns will be gathered and analyzed. The first registration for the pilot study was in January 2023, and the participants were recognized as high-risk for PE. In addition, enrollment in the main study will begin as of October 2023. Key words: Pre-eclampsia, Aspirin, Color doppler ultrasonography, Pregnancy, First trimester, Pregnancy-associated plasma protein-A. Key words: Pre-eclampsia, Aspirin, Color doppler ultrasonography, Pregnancy, First-trimester, Pregnancy-associated plasma protein-A