Showing papers by "Nima Naderi published in 2020"
TL;DR: An injectable electroactive hydrogel based on pluronic-chitosan/aniline-pentamer with proper conductivity around 10-4 S/cm is developed to achieve the functional repair of the hippocampus following the ischemic defect.
27 citations
TL;DR: In this article, high-performance ultraviolet (UV) detectors were designed based on porous silicon carbide (SiC) thin films on silicon (Si) substrate using an integrated current source.
26 citations
TL;DR: In this paper, a new technique was presented in order to enhance the efficiency of graphene-based heterojunction solar cells by employing a textured silicon (Si) substrate, and two sets of devices were fabricated based on flat and pyramidal structure of Si.
22 citations
TL;DR: In this article, Europium oxide was added to the composite as a reinforcing phase at 5% by the chemical deposition method and their structural and phase properties were studied by X-ray diffraction.
18 citations
TL;DR: In this paper, high-speed performance ultraviolet (UV) detectors were successfully fabricated based on the ternary MnxZn1-xS (0.2, 0.4) thin films deposited by a simple spray pyrolysis method.
Abstract: The high-speed performance ultraviolet (UV) detectors were successfully fabricated based on the ternary MnxZn1-xS (0.2 ≤ x ≤ 0.4) thin films deposited by a simple spray pyrolysis method. The optoelectrical properties of the samples were modified by introducing the Mn impurities at high content to enhance the performance of UV detectors. Microstructural characteristics confirmed the well-incorporation of Mn2+ ions into the ZnS lattice having nanocrystalline nature with homogeneous surface and strong adherence to the substrates. The optical measurements revealed that at the higher Mn2+ concentration, the optical transmittance increased over 95 % in the visible to near-infrared regions. Compared to the pure ZnS, the values of bandgap energy were found to blue-shift about 0.14 eV due to both quantum confinement and Burstein-Moss theories. Meanwhile, the Urbach energy decreased dramatically, leading to a considerable reduction of the electron-phonon interaction. The photoluminescence (PL) spectra revealed that the PL emission intensity was enhanced by introducing excess charge carriers through increasing the Mn2+ concentration, which can improve the generation of electron-hole pairs in the alloys. The photoresponse characterization featured a tremendous photosensing and photoswitching for the fabricated UV detectors, in which an excellent UV-B responsivity and high visible rejection were observed for the devices. For the UV detector based on the Mn0.4Zn0.6S thin film, the current gain greatly improved over 4.5 times compared to the pure ZnS one. Likewise, the photoresponse speed of the samples was found to enhance over 5 times, considerably.
15 citations
TL;DR: A novel series of 1, 2, 3-triazole-5-carboximidamide derivatives were designed, synthesized, and inhibitory activity evaluated against the DPP-4 enzyme, finding that compound 6a showed a significant decrease in blood glucose levels of diabetic rats, which was similar to sitagliptin as a standard.
13 citations
TL;DR: In this article, the intrinsic instability of optical and electrical properties of porous silicon (PS) was minimized by deposition of reduced graphene oxide (rGO) on a bare PS substrate using electrophoretic deposition (EPD) technique.
Abstract: In this research, the intrinsic instability of optical and electrical properties of porous silicon (PS) was minimized by deposition of reduced graphene oxide (rGO). The optoelectrical properties of the devices based on PS substrates showed a lack of stability under prolonged exposure to illumination. Therefore, despite many advantages of PS (e.g. high specific surface area), its application in electronic industries has been hindered. To resolve this problem, a thin layer of rGO was deposited on a bare PS substrate using electrophoretic deposition (EPD) technique. In order to obtain a high-quality porous substrate, the etching time was optimized in electrochemical etching of silicon. The most intense photoluminescence (PL) peak was reported for the sample etched for 20 min which could be due to its high absorption coefficient and large surface area. Moreover, a blue shift was observed in the PL peak position which can be assigned to quantum confinement effect reflecting the minimum crystallite size of this sample. The morphological study of the samples revealed complete coverage of the PS substrate by rGO. After graphene deposition, the PL quenching of PS samples was arrested even under prolonged exposure to laser illumination. For examining the electrical properties, metal-semiconductor-metal photodetectors were fabricated on bare PS and rGO/PS substrates. The results indicated that the photocurrent of the PS sample was diminished under 30-minute exposure to photons. However, the device based on rGO/PS illustrated higher photocurrent stability reflecting that the stability of optoelectrical properties of porous silicon could be enhanced by rGO deposition.
10 citations
TL;DR: In this article, the use of ZnO thin films, as anti-reflective layers of solar cells, is presented, where the thin films were synthesized through a sol-gel method and then deposited on a P-N silicon substrate using the spin-coating technique.
Abstract: In this research, the use of ZnO thin films, as anti-reflective layers of solar cells, is presented. The thin films were synthesized through a sol–gel method and then deposited on a P–N silicon substrate using the spin-coating technique. The effect of the ZnO thin films on the efficiency of a solar cell piece was then investigated. To synthesize the ZnO films, zinc acetate dihydrate was used as the precursor, monoethanolamine (MEA) was employed as the stabilizer, and 2-methoxyethanol was used as the solvent. Moreover, to investigate the effect of the sol–gel solution concentration on the formation of ZnO nanoparticles, samples with various concentrations were prepared, and after deposition, the solar cell piece was fabricated. The ZnO thin films prepared were characterized using X-ray diffraction and field-emission-scanning electron microscopy, and a four-point probe was used to measure the surface resistance of the sample. The obtained results indicated that the nano-structured ZnO films with hexagonal crystallites and 30–50 nm particle sizes were successfully formed on the silicon substrate. In addition, the observations unraveled that the coated ZnO films could act as anti-reflection films improving the efficiency of silicon solar cells. All in all, it was concluded that the concentration of the sol–gel solution could have a considerable effect on the efficiency of the silicon solar cell.
9 citations
TL;DR: In this paper, the effect of ZnO seed layer on the growth of uniform CdS nanostructures was investigated using chemical bath deposition technique, and the influence of molar concentration of reagents on the surface morphology, structural and optoelectrical properties of the deposited thin films were examined.
9 citations
TL;DR: In silico predictions revealed that 8e can be a drug candidate with favorable pharmacokinetic properties and its possible anticancer mechanism through VEGFR-2 inhibition is revealed.
Abstract: Background Receptor Tyrosine Kinases (RTK) are the main family of cell surface receptors for growth factors, hormones and cytokines which are responsible for cell growth and differentiation and are considered as an important therapeutic target in cancer. Objective The aim of this study was to design, synthesise and conduct the biological evaluation of benzimidazole/ benzoxazole substituted triazolotriazines as new anticancer agents. Methods A series of benzimidazolyl and benzoxazolyl-linked triazolotriazines 8a-e and 9a-e were synthesized as receptor tyrosine kinase inhibitors. Target compounds were evaluated in HGF-induced cell proliferation assay in A549, MCF-7, HepG2 and MDA-MB-231 cancer cells. Results Hepatocellular carcinoma was the most sensitive cell line towards the tested compounds and 8e was the most potent one on HepG2 cells with an IC50 value of 5.13µM which was close to crizotinib (HepG2 IC50 = 4.35µM) as a standard c-Met kinase inhibitor. c-Met kinase assay of 8e showed that this compound is not capable of inhibiting this enzyme and subsequently molecular docking confirmed the low affinity of 8e towards c- Met active site and its possible anticancer mechanism through VEGFR-2 inhibition. Conclusion Further in silico predictions revealed that 8e can be a drug candidate with favorable pharmacokinetic properties.
7 citations
TL;DR: Structural–activity data acquired indicate that the β‐lactam ring moiety constitutes a suitable scaffold to design new 1,4‐diarylazetidin‐2‐ones with selective COX‐2 inhibitory activity.
Abstract: A new series of 1,4-diarylazetidin-2-one derivatives (β-lactams) were designed and synthesized to evaluate their biological activities as selective cyclooxygenase-2 (COX-2) inhibitors. In vitro COX-1 and COX-2 inhibition studies showed that all compounds were selective inhibitors of the COX-2 isozyme with IC50 values in the 0.05-0.11 µM range, and COX-2 selectivity indexes in the range of 170-703.7. Among the synthesized β-lactams, 3-methoxy-4-(4-(methylsulfonyl)phenyl)-1-(3,4,5-trimethoxyphenyl)azetidin-2-one (4j) possessing trimethoxy groups at the N-1 phenyl ring exhibited the highest COX-2 inhibitory selectivity and potency, even more potent than the reference drug celecoxib. The analgesic activity of the synthesized compounds was also determined using the formalin test. Compound 4f displayed the best analgesic activity among the synthesized molecules. Molecular modeling studies indicated that the methylsulfonyl pharmacophore group can be inserted into the secondary pocket of the COX-2 active site for interactions with Arg513 . The structure-activity data acquired indicate that the β-lactam ring moiety constitutes a suitable scaffold to design new 1,4-diarylazetidin-2-ones with selective COX-2 inhibitory activity.
TL;DR: A series of (E)-1,2-diarylethylidenehydrazine carboximidamides 2a–j were synthesized and characterized by NOESY experiment as anticonvulsant agents and their antiseizure activity was evaluated by intracerebroventricular administration of compounds.
Abstract: A series of (E)-1,2-diarylethylidenehydrazine carboximidamides 2a–j were synthesized and characterized by NOESY experiment as anticonvulsant agents and their antiseizure activity was evaluated by intracerebroventricular administration of compounds. Most of the compounds had significant protection against tonic-clonic seizures and 2a was found to be as equipotent as carbamazepine in seizures control. In order to find their anticonvulsant mechanism of action, 2a was subjected to further electrophysiological studies using patch-clamp technique. The results confirmed that this compound is neither a voltage-gated sodium channel blocker nor a NMDA/AMPA antagonist. Although 2a did not show any direct GABA agonistic activity, it could decrease EPSP and increase IPSP frequency without any change in amplitude. Finally, the results indicated most likely a presynaptic GABA-mediated mechanism of 2a for its antiseizure activity such as inhibition of the GABA-T which was validated by molecular docking.
TL;DR: Pyracantha species can be suggested as a safe herb useful to develop future drug formulations and functional foods, and the presence of interesting bioactive molecules, such as pyracrenic acid and fortuneanosides is revealed.
Abstract: Pyracantha spp are commonly called firethorn, and attract human attention due to their colorful berries These berries are eaten globally as a traditional remedy for treating different stomach abnormalities, and as a cooking ingredient for folk diets The present review aims to provide an overview on Pyracantha genus' geographical distribution and botanical description, traditional uses, phytochemical composition, biological activities and safety issues Several biological activities have been reported to Pyracantha species, namely antioxidant, anti-inflammatory, antimicrobial, larvicidal and cytotoxic properties, most of them attributed to the use of their fruits Pyracantha species phytochemical composition reveal the presence of interesting bioactive molecules, such as pyracrenic acid and fortuneanosides The currently reported biological activities to these plants derive from in vitro and in vivo studies, so that clinical trials are needed to confirm these preclinical results Nonetheless, Pyracantha species can be suggested as a safe herb useful to develop future drug formulations and functional foods
TL;DR: In this paper, a highly sensitive and high gain metal-semiconductor-metal photodetector was successfully fabricated based on textured silicon substrates, where a combination of porous and pyramidal structures of silicon was introduced to dramatically enhance the lightcapturing ability and minimize the reflection coefficient of the silicon substrate.