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Journal ArticleDOI: 10.1016/J.MSEC.2021.112004

Effective antimicrobial activity of ZnO and Yb-doped ZnO nanoparticles against Staphylococcus aureus and Escherichia coli.

02 Mar 2021-Materials Science and Engineering: C (Elsevier)-Vol. 123, pp 112004-112004
Abstract: Nanostructured Zn1-xYbxO (0.0 ≤ x ≤ 0.1) powders were prepared by the solution method using polyvinyl alcohol (PVA) and sucrose. The effect of the ytterbium doping content on the structural, morphological, optical and antimicrobial properties was analyzed. X-ray diffraction (XRD) analysis revealed that the hexagonal wurtzite structure was retained, and no secondary phases due to doping were observed. The crystallite size was under 20 nm for all the Zn1-xYbxO (0.0 ≤ x ≤ 0.1) powders. The optical band gap was calculated, and the results revealed that this value increased with the ytterbium content, and the Eg values varied from 3.06 to 3.10 eV. The surface chemistry of the powders was analyzed using X-ray photoelectron spectroscopy (XPS), and the results confirmed the oxidation state of ytterbium as 3+ for all the samples. Zn1-xYbxO (0.0 ≤ x ≤ 0.1) nanoparticles were tested as antimicrobial agents against Staphylococcus aureus and Escherichia coli, resulting in a potential antimicrobial effect at most of the tested concentrations. These results were used in an artificial neural network (ANN). The results showed that it is possible to generate a model capable of forecasting the absorbance with good precision (error of 1–2%).

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Topics: Ytterbium (50%), Wurtzite crystal structure (50%)
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Journal ArticleDOI: 10.1016/J.SEPPUR.2021.118853
S. Girish Kumar, R. Kavitha1Institutions (1)
Abstract: ZnO is a versatile semiconductor that finds prominence in the area of photocatalysis due to their compatible crystal structure and band gap edge potentials that are vital for the pollutant degradation reaction. Thus, fabrication of ZnO based nanomaterials with tailored properties remains as the trending topic in recent times. In this context, doping with lanthanide ion finds interesting because of their unique 4f electronic configuration which offers stupendous opportunity to modulate the optical, luminescent and surface acid-base properties of ZnO. This article provides concise overview about the influence of lanthanide ions dopant on the structure-optical properties of ZnO. The performance of Ln-ZnO towards the degradation of organic pollutants is discussed encompassing both the materials properties and photocatalytic reaction conditions under UV/visible and solar light. The co-doping of Ln-ZnO with non-metal/transition metal ion and modification of Ln-ZnO with carbon materials is also emphasized to underscore the recent advancements in this field. We anticipate that our review article provides adequate information into the rational design and development of Ln-ZnO for various applications.

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2 Citations


Open accessJournal ArticleDOI: 10.17352/2455-5363.000046
19 Aug 2021-
Abstract: Nanomaterials in drug delivery systems are emerging as a potential source of treatments. The bioavailability of nano-carriers depends upon various factors including their mode of administration, target specificity, availability of active compound and compatibility with biological system.

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Open accessJournal ArticleDOI: 10.1021/ACSAMI.1C17465
Ji-Ming Yu1, Ji-Ming Yu2, Da Luo1, Zhong-Jie Ma2  +3 moreInstitutions (2)
Abstract: Rare-earth elements (REEs) in industrial wastewaters have great value for recycling and reuse, but their characteristic of low concentration poses a challenge to an efficient enrichment from wastewaters. In recent years, thiometallates featuring two-dimensional layers have shown great potential in the enrichment of REEs via the ion-exchange process. However, investigations on thiometallates featuring three-dimensional anionic frameworks for the recovery of REEs have not been reported. Herein, K2Sn2S5 (KTS-2), a thiostannate possessing a three-dimensional porous framework, was chosen as an ion-exchange material for capturing REEs from an aqueous solution. Indeed, KTS-2 exhibited excellent ion-exchange performance for all 16 REEs (except Pm). Specifically, KTS-2 displayed a high capture capacity (232.7 ± 7.8 mg/g) and a short equilibrium time (within 10 min) for Yb3+ ions. In addition, KTS-2 had a high distribution coefficient for Yb3+ ions (Kd > 105 mL/g) in the presence of excessive interfering ions. Impressively, KTS-2 could reach removal rates of above 95% for all 16 REEs in a large quantity of wastewater with low initial concentration (∼7 mg/L). Moreover, KTS-2 could be used as an eco-friendly material for ion exchange of REEs, since the released K+ cations would not cause secondary pollution to the water solution.

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Open accessPosted ContentDOI: 10.21203/RS.3.RS-171786/V1
P. Raji1, K. Balachandra KumarInstitutions (1)
Abstract: Ti-doped ZnO (TixZn1-xO x = 0.00, 0.05, 0.10, 0.15) nanoparticles have been synthesized through co-precipitation approach. X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), UV–Visible spectroscopy, and Vibrating Sample Magnetometer (VSM) have been used to characterize the samples. X-Ray Diffraction (XRD) analysis manifested the hexagonal wurtzite structure. The crystallite size decreased from 37 to 29 nm as dopant concentration is increased. Fourier transform infrared analysis showed the absorption bands of ZnO, with few within the intensities. SEM investigation showed the irregular shape and agglomeration of the particles. Ti, Zn, and O composition were determined from EDX analysis and confirmed the purity of the samples. PL spectra showed a near-band edge emission and visible emission. Vibrating sample magnetometer (VSM) demonstrated pure and doped samples exhibited ferromagnetism behavior at room temperature.

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Topics: Wurtzite crystal structure (54%), Crystallite (51%), Scanning electron microscope (51%) ... read more

Open accessJournal ArticleDOI: 10.1016/J.APSUSC.2021.151764
Abstract: Antimicrobial activity of the Zn1-xErxO (0, 1, 5, 10 at.%) nanoparticles were tested against Staphylococcus aureus and Escherichia coli. The nanoparticles were successfully synthesized by wet chemical route, where polyvinyl alcohol and sucrose were used. The influence of erbium content in structural, optical, and antimicrobial activity was analyzed. The average crystallite size is under 15 nm for all the samples according to X-ray diffraction results, and no secondary phases were observed even at high erbium content. Optical results exhibit a blue shift in the ultra-violet region. The X-ray photoelectron spectroscopy analysis confirmed the variations of Zn/O ratio, together with particles size and band gap are key factor in antimicrobial properties. The microbiological essays exhibit to these nanoparticles as a high potential agent with antibacterial activity versus S. aureus, with lower impact in E. coli. The absorbance results of these assays were used in two theoretical approaches. At first, Gompertz model used in the regression analysis showed the best fit for bacterial growth. Additionally, an artificial neural network was trained to forecast the result of new experiments, showing a good performance.

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Topics: Absorbance (51%)
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83 results found


Journal ArticleDOI: 10.1351/PAC198557040603
Abstract: Mise au point comportant des definitions generales et la terminologie, la methodologie utilisee, les procedes experimentaux, les interpretations des donnees d'adsorption, les determinations de l'aire superficielle, et les donnees sur la mesoporosite et la microporosite

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18,120 Citations


Journal ArticleDOI: 10.1016/J.PLAPHY.2010.08.016
Abstract: Various abiotic stresses lead to the overproduction of reactive oxygen species (ROS) in plants which are highly reactive and toxic and cause damage to proteins, lipids, carbohydrates and DNA which ultimately results in oxidative stress. The ROS comprises both free radical (O(2)(-), superoxide radicals; OH, hydroxyl radical; HO(2), perhydroxy radical and RO, alkoxy radicals) and non-radical (molecular) forms (H(2)O(2), hydrogen peroxide and (1)O(2), singlet oxygen). In chloroplasts, photosystem I and II (PSI and PSII) are the major sites for the production of (1)O(2) and O(2)(-). In mitochondria, complex I, ubiquinone and complex III of electron transport chain (ETC) are the major sites for the generation of O(2)(-). The antioxidant defense machinery protects plants against oxidative stress damages. Plants possess very efficient enzymatic (superoxide dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX; glutathione reductase, GR; monodehydroascorbate reductase, MDHAR; dehydroascorbate reductase, DHAR; glutathione peroxidase, GPX; guaicol peroxidase, GOPX and glutathione-S- transferase, GST) and non-enzymatic (ascorbic acid, ASH; glutathione, GSH; phenolic compounds, alkaloids, non-protein amino acids and α-tocopherols) antioxidant defense systems which work in concert to control the cascades of uncontrolled oxidation and protect plant cells from oxidative damage by scavenging of ROS. ROS also influence the expression of a number of genes and therefore control the many processes like growth, cell cycle, programmed cell death (PCD), abiotic stress responses, pathogen defense, systemic signaling and development. In this review, we describe the biochemistry of ROS and their production sites, and ROS scavenging antioxidant defense machinery.

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Topics: Reactive oxygen species (60%), Superoxide dismutase (59%), Glutathione reductase (59%) ... read more

6,556 Citations


Open accessJournal ArticleDOI: 10.1128/CMR.00134-14
Abstract: Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

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Topics: Staphylococcal infections (57%), Staphylococcus infection (55%), Infective endocarditis (54%) ... read more

2,094 Citations


Journal ArticleDOI: 10.1016/S1473-3099(05)70295-4
Abstract: Staphylococcus aureus is a frequent cause of infections in both the community and hospital. Worldwide, the increasing resistance of this pathogen to various antibiotics complicates treatment of S aureus infections. Effective measures to prevent S aureus infections are therefore urgently needed. It has been shown that nasal carriers of S aureus have an increased risk of acquiring an infection with this pathogen. The nose is the main ecological niche where S aureus resides in human beings, but the determinants of the carrier state are incompletely understood. Eradication of S aureus from nasal carriers prevents infection in specific patient categories-eg, haemodialysis and general surgery patients. However, recent randomised clinical trials in orthopaedic and non-surgical patients failed to show the efficacy of eliminating S aureus from the nose to prevent subsequent infection. Thus we must elucidate the mechanisms behind S aureus nasal carriage and infection to be able to develop new preventive strategies. We present an overview of the current knowledge of the determinants (both human and bacterial) and risks of S aureus nasal carriage. Studies on the population dynamics of S aureus are also summarised.

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2,066 Citations


Abstract: ZnO nanoparticles (ZnO-NPs) were prepared by a sol–gel combustion method from a zinc acetate precursor and acetic acid. The ZnO-NPs were synthesized at calcination temperatures of 650 °C and 750 °C for 1 h. The synthesized ZnO-NPs were characterized by X-ray diffraction analysis (XRD) and TEM. The XRD results revealed that the sample product was crystalline with a hexagonal wurtzite phase. High-magnification transmission electron microscopy (TEM) showed single-crystal ZnO-NPs with nearly spherical shapes. The crystalline development in the ZnO-NPs was investigated by X-ray peak broadening. The Williamson–Hall (W–H) analysis and size–strain plot method were used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of the ZnO-NPs. The physical parameters such as strain, stress and energy density values were calculated more precisely for all the reflection peaks of XRD corresponding to the wurtzite hexagonal phase of ZnO lying in the range of 20°–100° from the modified form of the W–H plot assuming a uniform deformation model (UDM), uniform stress deformation model (USDM), uniform deformation energy density model (UDEDM) and by the size–strain plot method (SSP). The results obtained showed that the mean particle size of the ZnO-NPs estimated from the TEM, W–H analysis and the SSP method were highly intercorrelated.

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1,393 Citations