آنالیزهای محیطی و بهداشتی؛ مواد تعویض یون
abd-o-vahed Rahmani; Lida Jahangiri Kalchoni
Abstract
Heavy metals are among the most important aquatic pollutants due to their persistence, bioaccumulation potential, and adverse effects on living organisms, particularly humans. The present study was conducted during winter 2023 and summer 2024 to determine lead (Pb) and cadmium (Cd) concentrations in ...
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Heavy metals are among the most important aquatic pollutants due to their persistence, bioaccumulation potential, and adverse effects on living organisms, particularly humans. The present study was conducted during winter 2023 and summer 2024 to determine lead (Pb) and cadmium (Cd) concentrations in the muscle tissue of Lethrinus nebulosus collected from Bandar Lengeh, Bandar Abbas, and Qeshm coastal waters (Hormozgan Province, Iran), and to evaluate the potential human health risks associated with fish consumption. Following acid digestion of the samples, metal concentrations were determined using flame atomic absorption spectrophotometry (FAAS). The results showed that the highest concentrations of Pb and Cd were detected in samples collected from Qeshm, whereas the lowest concentrations were observed in Bandar Lengeh. The concentrations of both metals were below the maximum permissible limits established by FAO, WHO, FDA, NHMRC, and UKMAFF guidelines. Furthermore, the Estimated Daily Intake (EDI) values for both adults and children were lower than the reference doses recommended by the United States Environmental Protection Agency (USEPA). The calculated Hazard Index (HI) values were also below 1, indicating no significant non-carcinogenic health risk associated with the consumption of Lethrinus nebulosus from the studied areas. Continuous monitoring of heavy metal contamination in marine ecosystems is recommended to ensure seafood safety and environmental protection.
فرایندهای استخراج جدید و میکرواستخراج؛ تهیه نمونه؛ تکنیک های جداسازی برای گونه‌های سمی؛ آنالیز حرارتی
Reyhaneh Rahnama; Mohammad Ranjbar Dounchali; Mohammad Reza Jamali
Abstract
A novel and highly efficient solvent bar microextraction (SBME) method was developed for the preconcentration and determination of trace nickel in water samples. The technique integrates a melt-blown facemask layer (MLF) as the extraction support, a hydrophobic deep eutectic solvent (DES), and dimethylglyoxime ...
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A novel and highly efficient solvent bar microextraction (SBME) method was developed for the preconcentration and determination of trace nickel in water samples. The technique integrates a melt-blown facemask layer (MLF) as the extraction support, a hydrophobic deep eutectic solvent (DES), and dimethylglyoxime (DMG) as the chelating agent. Experimental conditions were optimized for maximum extraction efficiency, including an extraction time of 5 min, stirring rate: 300 rpm, pH: 10, sample volume: 200 mL, and MLF area: 14 cm². Elution was performed using 5 mL of ethanol, followed by quantification via flame atomic absorption spectrophotometry (FAAS). The method exhibited a linear range of 3–130 μg L-¹, a detection limit of 1 μg L-¹, a preconcentration factor of 40, and a relative standard deviation of 3.2% (n=10). The approach is rapid, cost-effective, environmentally friendly, and capable of providing precise trace nickel analysis in water samples with minimal solvent usage.
مواد کامپوزیت؛ الکتروآنالیز و تکنیک‌های الکتروشیمی تجزیه‌ای؛ کاربردهای محیطی، بالینی و بیولوژیکی
Marjan Rafiee; Masoumeh Javaheri
Abstract
Uridine is an important nucleoside involved in RNA biosynthesis and phospholipid metabolism in the brain. In the present study, uridine and several of its derivatives were theoretically investigated as potential inhibitors of Alzheimer's disease. The electron charge density at eight sensitive sites, ...
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Uridine is an important nucleoside involved in RNA biosynthesis and phospholipid metabolism in the brain. In the present study, uridine and several of its derivatives were theoretically investigated as potential inhibitors of Alzheimer's disease. The electron charge density at eight sensitive sites, including hydrogen acceptor atoms (N1, O4, O5, and O6) and hydrogen donor atoms (O1, O2, O3, and N2), was examined through the calculation and comparison of electric field gradients (EFGs) and nuclear quadrupole coupling constants (NQCCs). The results indicate that the presence of a phosphate group in compound 3 increases the electron density at the O1 atom compared with the other studied compounds. This finding is further supported by Natural Bond Orbital (NBO) analysis. The obtained results suggest that O1 may act as the most active site in these compounds, and its electron density appears to be directly related to their biological activity. Therefore, any structural modification or substitution that increases the electron density at this atom may contribute to the development of more effective therapeutic agents for Alzheimer's disease. All calculations were performed using Density Functional Theory (DFT) at the B3LYP/6-31G* level of theory. The HOMO–LUMO and molecular docking analyses consistently highlighted compound 3 as the most promising derivative among the investigated compounds, exhibiting favorable electronic characteristics and the strongest predicted binding affinity toward AChE.
کاربردهای شیمی تجزیه
Somayeh Farahmand; Mobina Ashtari; Reza Haji Hosseini; Gholamreza Bakhshi Khaniki
Abstract
Hepatitis B virus (HBV) infection remains a global health challenge, and mutations in the core antigen (HBcAg) can compromise the efficacy of current antiviral therapies. This study aimed to identify potential natural and FDA-approved compounds targeting wild-type (WPr) and P135Q mutant (MPr) HBcAg using ...
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Hepatitis B virus (HBV) infection remains a global health challenge, and mutations in the core antigen (HBcAg) can compromise the efficacy of current antiviral therapies. This study aimed to identify potential natural and FDA-approved compounds targeting wild-type (WPr) and P135Q mutant (MPr) HBcAg using a comprehensive in silico approach. Natural compounds were filtered using Lipinski's Rule of Five and ADMET profiling. Molecular docking was performed using AutoDock Vina (version 1.2.x, 2021), and the top-ranked complexes were subjected to 500 ns molecular dynamics simulations using GROMACS 2023 with the AMBER99SB force field. Structural and energetic analyses included RMSD, RMSF, radius of gyration (Rg), solvent-accessible surface area (SASA), hydrogen bonding, principal component analysis (PCA), and MM/PBSA binding free energy calculations. Among 5,000 screened phytochemicals, Carnosic acid (Csa) and Nordentatin (Nor) demonstrated favorable binding affinities (ΔG = −8.85 and −9.84 kcal/mol, respectively) with acceptable ADMET profiles. MD simulations revealed distinct binding mechanisms: Csa stabilized WPr through electrostatic interactions, while Nor stabilized MPr through persistent hydrogen bonds and van der Waals contacts involving Trp102, Ser106, and Tyr118. Binding free energy analysis suggested that Csa may have stronger affinity for the mutant form, whereas Nor appeared to favor the wild-type. The P135Q mutation significantly influenced ligand binding dynamics and interaction patterns, highlighting the structural differences between wild-type and mutant HBcAg. Our computational findings suggest that Csa and Nor may serve as potential candidates for HBcAg binding. However, these predictions are purely computational and require experimental validation to confirm their actual biological activity.
مواد کامپوزیت؛ الکتروآنالیز و تکنیک‌های الکتروشیمی تجزیه‌ای؛ کاربردهای محیطی، بالینی و بیولوژیکی
Robab Mohammadi; sheida Ahmadi; Fatemeh S Hosseininasab
Abstract
Photocatalysis and sonocatalysis are considered promising techniques employed for the degradation of organic pollutants through solar light, visible or UV light irradiation. In this study, TiO2/g-C3N4 nanocomposite was successfully fabricated using solvothermal route and studied for its ability to degrade ...
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Photocatalysis and sonocatalysis are considered promising techniques employed for the degradation of organic pollutants through solar light, visible or UV light irradiation. In this study, TiO2/g-C3N4 nanocomposite was successfully fabricated using solvothermal route and studied for its ability to degrade Rhodamine B (RhB), when exposed to UV light. The as-prepared nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and photoluminescence (PL) spectroscopy. The solvothermal method did not modify the crystalline structure of the TiO2 and g-C3N4 but enhanced the surface area by interlayer delamination of g-C3N4 . The nanocomposite exhibited commendable photocatalytic performances with 99% degradation efficiency of RhB attained in 10 min. The enhanced photocatalytic activities were attributable to UV light-harvesting characteristics and the formation of an S-scheme heterojunction system between two catalysts which promotes interfacial charge separation efficiency and longer charge carrier lifespan. Furthermore, TiO2/g-C3N4 nanocomposite showed high sonocatalytic activity for the degradation of RhB. TiO2/g-C3N4 nanocomposite exhibited the best degradation efficiency of 99.5 % against RhB within 8 min under US light irradiation. Sonocatalytic degradation of organic dye using prepared nanocomposite could be described by the mechanisms of hot spots and sonoluminescence. Based on results, the photocatalytic degradation of RhB via TiO2/g-C3N4 nanocomposite needs more time. The reusability of TiO2/g-C3N4 was also examined in order to assess the composite sustainability.
مواد کامپوزیت؛ الکتروآنالیز و تکنیک‌های الکتروشیمی تجزیه‌ای؛ کاربردهای محیطی، بالینی و بیولوژیکی
Effat Esmaeili Shahri
Abstract
Copper oxide nanoparticles were prepared by a green sol-gel method employing aqueous Cressa cretica leaf extract and copper(II) nitrate trihydrate as the copper precursor. The resulting nanoparticles were subsequently used as carriers for the anticancer drug 5-fluorouracil (5-FU). Physicochemical characterization ...
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Copper oxide nanoparticles were prepared by a green sol-gel method employing aqueous Cressa cretica leaf extract and copper(II) nitrate trihydrate as the copper precursor. The resulting nanoparticles were subsequently used as carriers for the anticancer drug 5-fluorouracil (5-FU). Physicochemical characterization was performed by Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), field-emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (FESEM/EDX), dynamic light scattering (DLS), zeta potential measurements, and thermogravimetric/differential thermal analysis (TGA/DTA). Drug-loading efficiency was quantified by high-performance liquid chromatography (HPLC), and the influence of reaction medium pH, contact time, and nanoparticle concentration on loading performance was systematically investigated to identify optimal conditions. The synthesized CuO nanoparticles were spherical, highly pure, and possessed a cubic crystalline structure, with a mean particle size of approximately 39 nm and a zeta potential of -15.6 mV. Under optimal loading conditions (pH 5.50, 5 h contact time, 0.015 g of CuO nanoparticles), approximately 40% of 5-FU was adsorbed onto the nanoparticle surface. MTT cytotoxicity assay demonstrated concentration-dependent cell death in Huh-7 hepatocellular carcinoma cells, with an IC50 of approximately 250 mg/L, a result consistent with an acceptable biocompatibility profile.
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