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1.
Appl Radiat Isot ; 210: 111380, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38830278

RESUMO

This study explores the structural and luminescent properties of terbium (Tb³âº)-doped lanthanum aluminium borate (LaAl2B4O10, abbreviated as LAB) phosphors, a novel host lattice for Tb³âº doping. LAB:Tb³âº phosphors, with varying dopant concentrations, were synthesized using a microwave-assisted combustion synthesis approach and characterized using X-ray diffraction (XRD), Rietveld refinement, and photoluminescence spectroscopy at both room and low temperatures. The structural analysis confirmed the hexagonal crystal structure of LAB and revealed successful incorporation of Tb³âº ions without altering the fundamental lattice. Luminescence studies demonstrated that the LAB:Tb³âº phosphors show strong green emission primarily attributed to the 5D4→7F5 transition of Tb³âº. The optimal doping concentration was determined to be 5 wt% Tb³âº, which provided maximum luminescence efficiency. This concentration also allowed for a critical study of energy transfer mechanisms within the phosphor, revealing dipole-dipole interactions with a critical distance of 9.80 Å between Tb³âº ions. Additionally, the CIE chromaticity coordinates of LAB:0.05 Tb³âº were precisely determined to be (0.289, 0.4460), indicating the potential for high-quality green emission suitable for solid-state lighting and display technologies. This work not only demonstrates the potential of LAB:Tb3+ as a highly efficient green luminescent material, but also sheds light on the mechanisms responsible for energy transfer and concentration quenching.

2.
Appl Radiat Isot ; 208: 111308, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38555847

RESUMO

This study explores the structural and optical qualities of LaCa4O(BO3)3 (LACOB) phosphors doped with Eu3+, Dy3+, and Tb3+ using a microwave-assisted sol-gel technique. It uncovers oxygen-related luminescence defects in LACOB, highlighting emission peaks at 489 and 585 nm for Dy3+, a distinct sharp peak at 611 nm for Eu3+ in the red spectrum, and a notable green emission for Tb3+ due to specific transitions. The photoluminescence (PL) analysis indicates that luminescence is optimized through precise doping, leveraging dipole interactions, and localized resonant energy transfer, which are influenced by dopant concentration and spatial configuration. Temperature studies show emission intensity variations, particularly noticeable below 100 K for Tb3+ doped samples, demonstrating the nuanced balance between thermal quenching and luminescence efficiency. This temperature dependency, alongside the identified optimal doping conditions, underscores the potential of these materials for advanced photonic applications, offering insights into their thermal behavior and emission mechanisms under different conditions.

3.
Int J Biol Macromol ; 258(Pt 1): 128885, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38143064

RESUMO

The harmful cationic dyes present in industrial waste significantly decrease the effectiveness of remedy operations. Considering the horrendous impact of these dyes on the environment and biodiversity, silver bromide (AgBr) and chitosan (CS) doped copper ferrite (CuFe2O4) nanostructures (NSs) were prepared by the co-precipitation route. In this work, The surface characteristics of CuFe2O4 can be altered by CS, potentially enhancing its catalytic reaction compatibility. The functional groups in CS interact with the surface of CuFe2O4, influencing its catalytic behavior. AgBr can have an impact on the dynamics of charge carriers in the composite. Better charge separation and transfer which is essential for catalytic processes. The catalytic degradation of RhB was significantly enhanced (100 %) using 4 wt% of AgBr-doped CS-CuFe2O4 catalysts in a basic medium. The significant inhibitory zones (9.25 to 17.95 mm) inhibitory in maximum doses were seen against Gram-positive bacteria (S. aureus). The bactericidal action of AgBr/CS-doped CuFe2O4 NSs against DNA gyraseS.aureus and tyrosyl-tRNAsynthetase S. aureus was rationalized using molecular docking studies, which supported their function as inhibitors.


Assuntos
Quitosana , Simulação de Acoplamento Molecular , Rodaminas , Staphylococcus aureus , Corantes
4.
Luminescence ; 38(7): 1064-1086, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36378274

RESUMO

The penicillin derivative amoxicillin (AMX) plays an important role in treating various types of infections caused by bacteria. However, excessive use of AMX may have negative health effects. Therefore, it is of utmost importance to detect and quantify the AMX in pharmaceutical drugs, biological fluids, and environmental samples with high sensitivity. Therefore, this review article provides valuable and up-to-date information on nanostructured material-based optical and electrochemical sensors to detect AMX in various biological and chemical samples. The role of using different nanostructured materials on the performance of important optical sensors such as colorimetric sensors, fluorescence sensors, surface-enhanced Raman scattering sensors, chemiluminescence/electroluminescence sensors, optical immunosensors, optical fibre-based sensors, and several important electrochemical sensors based on different electrode types have been discussed. Moreover, nanocomposites, polymer, and MXenes-based electrochemical sensors have also been discussed, in which such materials are being used to further enhance the sensitivity of these sensors. Furthermore, nanocomposite-based photo-electrochemical sensors and the market availability of biosensors including AMX have also been discussed briefly. Finally, the conclusion, challenges, and future perspectives of the above-mentioned sensing techniques for AMX detection are presented.


Assuntos
Técnicas Biossensoriais , Nanocompostos , Antibacterianos , Amoxicilina , Técnicas Biossensoriais/métodos , Imunoensaio , Técnicas Eletroquímicas/métodos
5.
Molecules ; 27(22)2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36432031

RESUMO

Iron oxide nanoparticle (ION)-based ferro-nanofluids (FNs) have been used for different technological applications owing to their excellent magneto-rheological properties. A comprehensive overview of the current advancement of FNs based on IONs for various engineering applications is unquestionably necessary. Hence, in this review article, various important advanced technological applications of ION-based FNs concerning different engineering fields are critically summarized. The chemical engineering applications are mainly focused on mass transfer processes. Similarly, the electrical and electronics engineering applications are mainly focused on magnetic field sensors, FN-based temperature sensors and tilt sensors, microelectromechanical systems (MEMS) and on-chip components, actuators, and cooling for electronic devices and photovoltaic thermal systems. On the other hand, environmental engineering applications encompass water and air purification. Moreover, mechanical engineering or magneto-rheological applications include dampers and sealings. This review article provides up-to-date information related to the technological advancements and emerging trends in ION-based FN research concerning various engineering fields, as well as discusses the challenges and future perspectives.


Assuntos
Eletrônica , Sistemas Microeletromecânicos , Tecnologia , Eletricidade , Nanopartículas Magnéticas de Óxido de Ferro
6.
ACS Omega ; 7(36): 31778-31788, 2022 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-36120042

RESUMO

This paper reports the facile one-pot synthesis of glycidol via the transesterification of glycerol with dimethyl carbonate using KNO3/Al2O3 nanoparticles as supporting catalysts. KNO3/Al2O3 nanoparticles were prepared by the impregnation method. XRD and FT-IR analyses indicated an interaction between KNO3 and Al2O3 that enabled the decomposition of KNO3 during the process and resulted in the formation of KAl5O8, the Al-O-K group, and K2O. K2O was recognized as one of the active sites of the catalyst. SEM results indicated the high performance of the supporting catalyst, as the catalytic activity depended on both the number of catalytic active sites and their distribution. The yield of glycidol was 64% at the expense of 95% glycerol under moderate reaction conditions (120 min, 1 atm, and 70 °C). The nanocatalyst prepared at 800 °C with a loading amount of 30% KNO3 was the most efficient for the synthesis of glycidol. Furthermore, the catalyst was recovered and reused without a loss of efficiency even after the fourth recycling. A plausible mechanism for the one-pot synthesis of glycidol has also been proposed.

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