Publications by authors named "Afkhami A"

Determining 2,4,6-trinitrotoluene (TNT) in aqueous solution is of great importance for public security, environment, and public health protection. The covalent organic framework (COF) based fluoresce probes are still of interest in developing the sensor-based detection systems for TNT. So, a novel fluorescence solid-state probe based on a melamine-based COF (SNW1)for TNT detection was established for the first time.

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Article Synopsis
  • * The nanocomposite exhibited electrocatalytic capabilities that allowed for the sensitive and selective detection of AGM using square wave anodic stripping voltammetry, with optimal conditions established through experimental design.
  • * The detection method demonstrated impressive sensitivity, with a limit of detection of 0.002 μmol/L, and was effective in analyzing AGM in biological samples such as urine, serum, and saliva.
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The design of electrochemical sensors is crucial considering important factors such as efficiency, low cost, biocompatibility, and availability. Manganese oxides are readily available, low-cost, and biocompatible materials, but their low conductivity limits their efficiency as sensors. Today, morphology engineering of manganese oxide has been one of the most common research topics, because manganese oxides' electrochemical properties are highly dependent on their morphologies.

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The study presented here describes the characterization and synthesis of a triazine-based covalent organic framework using different analytical procedures such as scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, cyclic voltammetry, Brunauer-Emmett-Teller analysis, and electrochemical impedance spectroscopy. The synthesized COF was then utilized as an electrocatalytic modifier for the selective and sensitive determination of Pb and Cd at nanomolar levels via square wave anodic stripping voltammetry. A Plackett-Burman design was employed to screen operational parameters influencing the sensitivity of the electroanalytical method, followed by optimization of the significant variables using Box-Behnken design.

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This research presents a compact portable electronic gas sensor that can be monitored through a smartphone application. The smart sensor utilizes three state-of-the-art sensors. The sensors integrate an ESP8266 microcontroller within the same device.

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The aim of this study was to develop a new method for sampling and analyzing polycyclic aromatic hydrocarbons in the air. This was achieved by utilizing a needle trap device packed with a modified porous aromatic framework coated with magnetic nanoparticles (PAF-6-MNPs). The modified adsorbent underwent qualitative evaluation using Fourier-transform infrared spectroscopy and X-ray diffraction, as well as scanning and transmission electron microscopy.

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This paper reports on the development of a flexible-wearable potentiometric sensor for real-time monitoring of sodium ion (Na), potassium ion (K), and pH in human sweat. NaMnO, polyaniline, and KCo[Fe(CN)] were used as sensing materials for Na, H and K monitoring, respectively. The simultaneous potentiometric Na, K, and pH sensing were carried out by the developed sensor, which enables signal collection and transmission in real-time to the smartphone via a Wi-Fi access point.

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This paper presents the development and optimization of a cost-effective paper electrochemical sensor for the detection of TNT using FeO-Au core-shell nanoparticles modified with cysteamine (FeO@Au/CA). The sensor was constructed by modifying a graphite paste with the aforementioned nanoparticles, which facilitated the formation of a Meisenheimer complex between cysteamine and TNT as an electron donor and an electron acceptor, respectively. The central composite design was employed to optimize four key parameters pH, modifier percentage, contact time, and buffer type to enhance the performance of the sensor.

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In recent years, several nanocarrier synthesis methods have been developed. In cancer therapy, the use of smart nanocarriers is of interest. Smart nanocarriers respond to their environment and can release their cargo in a controlled manner under the action of internal or external stimuli.

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Electrochemical impedance spectroscopy (EIS) is a highly effective technique for studying the surface of electrodes in great detail. EIS-based electrochemical sensors have been widely reported, which measure the charge transfer resistance (R) of redox probes on electrode surfaces to monitor the binding of target molecules. One of the protective drugs against hemorrhagic cystitis caused by oxazaphosphorine chemotherapy drugs such as ifosfamide, cyclophosphamide and trophosphamide is Mesna (sodium salt of 2-mercaptoethanesulfonate).

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This paper reports on developing a low cost but efficient paired emitter-detector diode (PEDD)-based photometer. The photometer consists of a white light-emitting diode (LED) as the emitter diode, an RGB LED as the detector diode, and a multimeter for recoding the signal. The developed PEDD-based photometer was utilized for the determination of liquid bleach adulteration in cow milk samples.

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A serious challenge in transdermal iontophoresis (IP) delivery of insulin (INS) is the low permeability of the drug across the skin. In this paper, we introduced deep eutectic solvent (DESs) as novel chemical penetration enhancers (CPEs) for transdermal IP of INS across rat skin, both in vitro and in vivo. Three different DESs based on choline chloride (ChCl), namely, ChCl/UR (ChCl and urea), ChCl/GLY (ChCl and glycerol), and ChCl/EG (ChCl and ethylene glycol) in the 1:2 molar ratios have been prepared.

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Detection of trace amounts of 2,4,6-Trinitrotoluene as a widely used explosive in the military and industrial sectors is of vital importance due to security and environmental concerns. The sensitive and selective measurement characteristics of the compound still is considered a challenge for analytical chemists. Unlike conventional optical and electrochemical methods, the electrochemical impedance spectroscopy technique (EIS), has a very high sensitivity, but it faces a significant challenge in that it requires complex and expensive steps to modify the electrode surface with selective agents.

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It was demonstrated that the mechanism of the inner filter effect (IFE) can emerge well in the resonance Rayleigh scattering (RRS) technique and be utilized as a new analytical method in the design of innovative IFE-based sensors. To prove this process, silver nanocubes (Ag NCs) with tunable extinction spectra were selected as RRS probes, and three analytes, doxorubicin (DOX), sunitinib (SUN), and Alizarin Red S (ARS), were considered as the typical absorbers. In addition, in the presence of SUN as a typical analyte, the quenching of the RRS signal of Ag NCs, with λ of 419 nm, was linear in the range 0.

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Ampyra (AMP, 4-Aminopyridine) is a potassium channel blocker that attracts growing research interest due to its adverse effects at high doses. The fast analysis of AMP is challenging because it typically requires complex analytical techniques. In this research, we developed and validated a novel method to assess the fast and quantitative analysis of AMP from real samples.

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Despite the presence of light-sensitive species in the polyol synthesis of silver nanocubes, the influence of light on it has yet to be investigated. Herein, we demonstrated that light radiation, by generating plasmon-based hot electrons and subsequently increasing the reduction rate of Ag in the system, in addition to enhancing the growth rate of nanocubes, causes twinned seeds, which these seeds are then converted into nanorods and right bipyramids. With shorter, higher energy wavelengths, Ag reduction progresses more quickly, resulting in structures with more twin planes.

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Heavy metals determination is of great importance. In this respect, a recently synthesized melamine-based covalent organic framework (Schiff base network (SNW)) was used in this research as a novel modifier to alter a glassy carbon electrode for the simultaneous anodic stripping square wave voltammetric measurement of Pb and Hg ions. At first, the complexation of SNW with Pb and Hg ions were evaluated by density functional theory calculations.

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In this research, a highly sensitive electrochemical sensor was developed for the square wave anodic stripping voltammetric determination of Pb at ultra-trace levels. A Glassy carbon electrode was modified with an in-situ electroplated bismuth film and the nanocomposite of a recently synthesized melamine based covalent organic framework (schiff base network (SNW)) and FeO nanoparticles (FeO@SNW). The obtained results exhibit clearly that combination of FeO@SNW and in-situ electroplated bismuth film enhances the sensitivity of the modified electrode towards Pb remarkably.

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There is strong evidence that SARS-CoV-2 is spread predominantly by airborne transmission, with high viral loads released into the air as respiratory droplets and aerosols from the infected subject. The spread and persistence of SARS-CoV-2 in diverse indoor environments reinforces the urgent need to supplement distancing and PPE based approaches with effective engineering measures for microbial decontamination - thereby addressing the significant risk posed by aerosols. We hypothesized that a portable, single-pass UVC air treatment device (air flow 1254 L/min) could effectively inactivate bioaerosols containing bacterial and viral indicator organisms, and coronavirus without reliance on filtration technology, at reasonable scale.

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Phosphorylation of PI3Kγ as a member of lipid kinases-enzymes, plays a crucial role in regulating immune cells through the generation of intracellular signals. Deregulation of this pathway is involved in several tumors. In this research, diverse sets of potent and selective isoform-specific PI3Kγ inhibitors whose drug-likeness was confirmed based on Lipinski's rule of five were used in the modeling process.

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Developing new ultrasensitive assays for the detection of the presence, and determination of the serotype of the most poisonous material known i.e. botulinum neurotoxin (BoNT) is vital to human health and the wellbeing of the surrounding environment.

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A relatively new adsorbent based on covalent organic frameworks (COFs) was employed for the first time to extract and determine Trans, trans-muconic acid (tt-MA), Mandelic acid (MA), Hippuric acid (HA), and 3-Methylhippuric acid (m-MHA) in urine. For this purpose, microextraction was performed using the packed sorbent (MEPS) method. Following the extraction process, the prepared samples were specified via the high-performance liquid chromatography-ultraviolet detector system.

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Polyol synthesis of silver nanocubes (Ag NCs) under dark conditions yielded nanoparticles with high uniformity and purity, as well as edge lengths of 42 nm with good stability and scattering cross-section. These nanoparticles were characterized by SEM, TEM, and Uv-vis spectroscopy. The presence of polyvinylpyrrolidone (PVP) as a capping agent on the surface of Ag NCs, as well as its satisfactory interaction level with Haloperidol (Hp) as an antipsychotic drug, has led to the use of these nanoparticles as Resonance RayleighScattering (RRS) probe to measure Hp.

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Here, we present a wearable potentiometric ion sensor for real-time monitoring of sodium ions (Na) in human sweat samples using NaMnO as the sensing material. NaMnO is an attractive material for developing wearable electrochemical sensors due to its good Na incorporation ability, electrical conductivity, stability, and low fabrication cost. In the first step, the analytical performance of the electrode prepared using NaMnO is presented.

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