Field Emission Scanning Electron Microscopy Analysis Research Articles

MUNTINGIA CALABURA SILVER NANOPARTICLES DETERIORATE OXIDATIVE IMPAIRMENT WITH POTENT ANTIBACTERIAL ACTIVITY

Objective: The current study exemplifies the synthesis of silver nanoparticles using Muntingia calabura L. (Mc-AgNP’s) fruit extract utilizing a green approach and testing the efficacy of synthesized NP’s. Methods: The green synthesize approach was used to synthesis Mc-AgNP’s followed by characterization using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX), and Field Emission Scanning Electron Microscopy (FESEM). Radical scavenging activity was assessed using DPPH, FRAP, and H202, followed by antibacterial activity. Results: The characteristic features of synthesized Muntingia calabura silver nanoparticles (Mc-AgNP’s) were analyzed using FT-IR which particularizes different functional groups with a broadband at 3408 cm-1 representing hydroxyl (-OH) stretching a peak at 1593.27 cm-1 corresponds to C = O groups in amide whereas a dip at 1383 cm-1 represents C-N amine and C-O stretching of alcohol groups were found. The Crystallinity of synthesized Mc-AgNP’s exhibited face-centered cubic (fcc) crystalline structure and the bio-reduction of the silver ions in solution was monitored by Energy dispersive X-ray spectroscopy (EDX). The FESEM analysis indicates that Mc-AgNP’s were dispersed in the solution using micrographs and the size ranged from 10 to 60 nm. The synthesized Mc-AgNP’s efficiently scavenged free radicals in a dose-dependent manner with 69% for DPPH, 59.9% for FRAP, and 64% for H202 respectively. Further, the synthesized Mc-AgNP’s demonstrated a potent antimicrobial agent against tested bacterial and fungal strains with a maximum zone of inhibition observed in S. aureus, K. pneumonia, and P. vulgaris with 14.6, 13.8, and 12.4 mm. Similarly, antifungal activity with Trichoderma harzianum demonstrated the highest zone with 18 mm followed by Aspergillus oryzae with 7 mm. Conclusion: These results highlight the interesting potential of synthesized Mc-AgNP’s as an effective source of bioactive compounds with potent antioxidant and antibacterial activity.

Effect of Iodine Doped Pentacene Thin Film on the Performance of Organic Light Emitting Diode

The study investigated the effect of iodine-doped pentacene film as a buffer layer in an organic light-emitting diode (OLED). In this study, an ITO (indium tin oxide)-based sample is used as a reference device for comparative purposes. In OLED devices, the buffer layers were deposited using the doping of iodine vapor with the pentacene materials under proper conditions. The thermal treatment of the doped pentacene film results in increasing the conductivity of the buffer layer. Surface morphology for the bilayer anode was carried out by FESEM (Field Emission Scanning Electron Microscope) analysis. In our work, maximum luminance of 2345 cd/m2 and current efficiency of 5.4 cd/A are obtained, along with more stability performance under annealing treatment in the device structure of FTO/iodine-doped pentacene (30 nm)/TPD [N, N′-Bis(3-methyl phenyl)-N, N′-diphenylbenzidine] (44 nm)/Alq3 [Tris(8-hydroxyquinoline)aluminum(III)] (52 nm)/LiF (lithium fluoride) (5 nm)/Al (aluminum) (110 nm).

Visible light degradation of antibiotics catalyzed by nanoporous carbon/V2O5 nanocomposite: structural, optical and electrochemical properties

In this study, nanoporous carbon (NPC) decorated V2O5 (NPC/V2O5) nanocomposite synthesized by a hydrothermal technique using biomass-derived NPC nanoflakes towards the application of berberine hydrochloride (BH) dye degradation under visible light irradiation. The prepared samples were characterized by X-ray Diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray (EDX), UV-Visible and Photoluminescence (PL) spectroscopy. Charge transfer resistance was measured by electrochemical impedance spectroscopy (EIS) and liner sweep voltammetry (LSV). XRD studies confirm the orthorhombic crystal structure of NPC/V2O5 nanocomposite. FE-SEM and TEM analysis validate their particle-like and sheet-like morphology of V2O5 and NPC respectively. Further, UV-visible DRS and PL spectra of the green synthesized NPC/V2O5 nanocomposite exhibited a low band-gap and reduced recombination rate compared to the pure counterpart which is better light-absorbing ability in the visible light region. Batch experiments represent the incorporation of NPC and V2O5 would lead to an increase the photocatalytic performance of NPC/V2O5 toward BH dye degradation. During the photocatalytic reaction, the NPC/V2O5 nanocomposite degraded rate around 97.7% against BH dye within 80 min while pure V2O5 degraded 92.5% of BH dye under same visible light irradiation time. Finally, the cyclic stability experiment exhibits the photocatalyst even stable after five consecutive tests.

A Comparative Study on the Electrocatalytic Efficiency of Coupled (CuO-Co3O4) vs. Mixed (CuCo2O4) Metal Oxides: Probed by Hydrazine Oxidation and Sensitive Determination

This work reports the synthesis of copper- and cobalt-based coupled and mixed metal oxides (CuO-Co3O4 and CuCo2O4, respectively) utilizing a simple hydrothermal and calcination approach. CuO-Co3O4, CuCo2O4, and the control samples were characterized by powder X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray, and X-ray photoelectron spectroscopy. TEM and FE-SEM analyses of CuO-Co3O4 reveal the presence of two distinct morphologies: rod- and sphere-shaped particles (CuO and Co3O4, respectively). Further, CuO-Co3O4 was efficiently utilized as an electrocatalyst for the selective oxidation of hydrazine (Hyz). CuO-Co3O4 shows a high redox response compared to CuO, Co3O4, CuCo2O4, and the physical mixture of CuO and Co3O4 (CuO/Co3O4). This enhanced performance is attributed to the synergistic interaction between the metal ions caused by their close proximity and the increased exposure of surface active sites. CuO-Co3O4 shows a broad linear range (1-3500 µM), a low detection limit (0.29 µM), and high sensitivity (0.5756 µA µM-1 cm-2) for the Hyz determination. Kinetic parameters, for instance the diffusion coefficient and catalytic rate constant for Hyz oxidation were obtained using chronoamperometry. Additionally, CuO-Co3O4 was effectively utilized to analyze Hyz in real samples with acceptable recovery rates.

Rosmarinic Acid Exhibits Antifungal and Antibiofilm Activities Against Candida albicans: Insights into Gene Expression and Morphological Changes

Candida species, opportunistic pathogens that cause various infections, pose a significant threat due to their ability to form biofilms that resist antifungal treatments and immune responses. The increasing resistance of Candida spp. and the limited availability of effective treatments have prompted the research of natural compounds as alternative therapies. This study assessed the antifungal properties of RA against Candida species, focusing on its impact on C. albicans biofilms and the underlying mechanisms. The antifungal efficacy of RA was evaluated using the CLSI M27-A3 microdilution method on both fluconazole-susceptible and -resistant strains. Biofilm formation by C. albicans was assessed through a crystal violet assay, while its antibiofilm activity was analyzed using an MTT assay and field emission scanning electron microscopy (FESEM). Gene expression related to biofilm formation was studied using quantitative real-time PCR (qRT-PCR), and statistical analysis was performed with an ANOVA. Among the 28 Candida strains tested, RA exhibited minimum inhibitory concentration (MIC) values ranging from 160 to 1280 μg/mL. At a 640 μg/mL concentration, it significantly reduced the expression of genes associated with adhesion (ALS3, HWP1, and ECE1), hyphal development (UME6 and HGC1), and hyphal cAMP-dependent protein kinase regulators (CYR1, RAS1, and EFG1) in RAS1-cAMP-EFG1 pathway (p < 0.05). FESEM analysis revealed a reduction in hyphal networks and disruptions on the cell surface. Our study is the first to demonstrate the effects of RA on C. albicans adhesion, hyphae development, and biofilm formation through gene expression analysis with findings supported by FESEM. This approach distinguishes our study from previous studies on the effect of RA on Candida. However, the high MIC values of RA limit its antifungal potential. Therefore, more extensive research using innovative methods is required to increase the antifungal effect of RA.

The Influence of Temperature on the Spatial Distribution of AuNPs on a Ceramic Substrate for Biosensing Applications

In this study, we investigated the spatial distribution and homogeneity of gold nanoparticles (AuNPs) on an alumina (Al2O3; AAO) substrate for potential application as surface-enhanced Raman scattering (SERS) sensors. The AuNPs were synthesized through thermal treatment at 450 °C at varying times (5, 15, 30, and 60 min), and their distribution was characterized using field-emission scanning electron microscopy (FE-SEM) and scanning transmission electron microscopy (STEM). The FE-SEM and STEM analyses revealed that the size and interparticle distance of the AuNPs were significantly influenced by the duration of thermal treatment, with shorter times promoting smaller and more closely spaced nanoparticles, and longer times resulting in larger and more dispersed particles. Raman spectroscopy, using Rhodamine 6G (R6G) as a probe molecule, was employed to evaluate the SERS enhancement provided by the AuNPs on the AAO substrate. Raman mapping (5 µm × 5 µm) was conducted on five sections of each sample, demonstrating improved homogeneity in the SERS effect across the substrate. The topological features of the AuNPs before and after R6G incubation were analyzed using atomic force microscopy (AFM), confirming the correlation between a decrease in surface roughness and an increase in R6G adsorption. The reproducibility of the SERS effect was quantified using the maximum intensity deviation (D), which was found to be below 20% for all samples, indicating good reproducibility. Among the tested conditions, the sample synthesized for 15 min exhibited the most favorable characteristics, with the smallest average nanoparticle size and interparticle distance, as well as the most consistent SERS enhancement. These findings suggest that AuNPs on AAO substrates, particularly those synthesized under the optimized condition of 15 min at 450 °C, are promising candidates for use in SERS-based sensors for detecting cancer biomarkers. This could be attributed to temperature propagation promoted at the time of synthesis. The results also provide insights into the influence of thermal treatment on the spatial distribution of AuNPs and their subsequent impact on SERS performance.

Performance of yellow and pink oyster mushroom dyes in dye sensitized solar cell

A solar photovoltaic (PV) cell, is an electrical device that uses the PV effect to convert light energy into electricity. The application of oyster mushroom dyes in dye sensitized solar cell (DSSC) is a novel strategy to substitute the costly chemical production process with easily extractable, environmentally acceptable dyes. Both dyes of yellow and pink oyster mushrooms were extracted using the same process but dried into powder form using two techniques, warm drying and freeze drying. The characterization was carried out utilizing current-voltage (I-V) characterization for electrical properties, Ultraviolet-Visible (UV-Vis) spectrophotometer for optical properties, Field Emission Scanning Electron Microscopy (FESEM), and Atomic Force Microscopy (AFM) for the structural properties. It was found that freeze-dried pink and yellow oyster mushroom had shown the good properties for DSSC application as it produced energy bandgap which lies within the range of efficient dye sensitizer; 1.7 eV and 2.2 eV, the most uniform distribution of pores and a nearly spherical form in FESEM analysis, and AFM result obtained with the highest root mean square (RMS) roughness value (26.922 and 34.033) with stereoscopic morphologies. The data proved that mushroom dyes can be incorporated in DSSC with the optimization of drying method in the extraction process, dilution of dye and the layer of deposition on the glass substrate. The current density-voltage (J–V) characteristics of fabricated DSSC was characterized using Newport Oriel Sol3A solar simulator under AM 1.5 Sun condition (100 mW/cm2, 25 oC). From the result obtained by solar simulator, the fabricated FTO/TiO2/Pleurotus djamor dye/Pt indicated the Voc of 0.499 V and Jsc of 0.397 mA/cm2.

Hydrothermal synthesis and morphological evolution of hexagonal ceria microrod structures

CeriaBTC (CeO2-1,3,5-Benzenetricarboxylic acid) microstructures have been synthesized through hydrothermal methods. Field Emission Scanning Electron Microscopy (FE-SEM) micrographs and X-ray diffraction (XRD) data reveal that the microstructure exhibit hexagonal rod-like structures with average diameters 1.9 ± 0.17 µm and length 5.7 ± 0.19 µm, synthesized at 130 °C for 72 h. Elevating the reaction temperature or duration leads to gradual morphological evolution in micromaterial shape and size (aspect ratio), stabilizing at 3.51. This signifies an ongoing chemical transformation driving morphological alteration. Fourier transform infrared spectroscopy (FT-IR) reveals the presence of an organic linker in the CeriaBTC microrods. Results from XRD, FE-SEM, FT-IR, and thermogravimetric analysis (TGA) suggest a chemical transformation from hexagonal type CeriaBTC to Ceria microrods at higher calcination temperatures of 400 °C for 4 h. The development of hierarchical morphologies, transitioning from hexagonal CeriaBTC rods to Ceria microstructure powder, has been observed to rely on both the orientation of the organic precursor (1,3,5-Benzenetricarboxylic acid) and the specific calcination temperature applied.

The antioxidant and selective apoptotic activities of modified auraptene-loaded graphene quantum dot nanoparticles (M-AGQD-NP)

BackgroundPancreatic and Gastric cancers are very aggressive and deadly types of cancer that require effective treatment strategies to stop their progression. Nano-drug delivery systems, like those using Auraptene-loaded GQD nanoparticles, play a crucial role in addressing this need by delivering targeted and controlled treatments to cancer cells, making treatment more effective, and reducing side effects. The study focused on investigating the effects of Auraptene, an efficient anticancer compound when loaded into Graphene Quantum Dots (GQDs) on types of human cancer cells.MethodsTo create auraptene-loaded graphene quantum dot nanoparticles (AGQD-NP) (Unmodified and modified types) a combination of hydrothermal and high-energy homogenization methods was used. The nanoparticles were characterized by conducting DLS (Dynamic light scattering), FTIR (Fourier-transform infrared spectroscopy), FESEM (Field Emission Scanning Electron microscopy), and zeta potential analysis. bioactivity of AGQD-NP was assessed through tests, including antioxidant capacity measured by ABTS and DPPH scavenging abilities well as cytotoxicity tested using MTT assay on both human cancer cell lines and normal human vascular endothelial cells.ResultsThe modified AGQD-NP (M-AGQD-NP) demonstrated antioxidant properties by neutralizing free radicals. They also displayed selective toxicity, towards human gastric adenocarcinoma cell-line (AGS) and human pancreatic adenocarcinoma (PANC) cancer cells with IC50 values recorded at 78.8 µg/mL and 89.72 µg/mL respectively. The specific targeting of gastric cancer cells was evident from the differing IC50 values compared to the Human breast adenocarcinoma cell line (MCF-7), Human hepatocellular carcinoma cell line (Hella), and normal vascular endothelial cells (Huvec). Additionally, the induced apoptotic death, in the human pancreatic adenocarcinoma (PANC) cancer cells was confirmed through AO/PI staining and Annexin-based flow cytometry revealing increased expression levels of P53, Caspase3, BAX, and Caspase8.ConclusionIn summary, the M-AGQD-NP have shown encouraging effects displaying antioxidant capabilities and a specific focus, on pancreatic and gastric cancer cells. These findings indicate uses for AGQD-NP as an efficient apoptosis inducer in cancer treatment. Additional In-vivo researches are required to validate their effectiveness, in living organisms.

Synthesis and characterization of ZnO–NiO binary nanocomposites by hydrothermal technique for gas sensing and photocatalytic applications

Inorganic photocatalytic materials exhibiting a highly efficient response to ultraviolet-visible light spectrum have become a subject of widespread global interest. Nanocomposite metal oxides, particularly Nickel Oxide (NiO) and Zinc Oxide (ZnO), have gained attention for their diverse applications in gas sensing and photocatalytic processes. In this work, ZnO-NiO (ZnO0.6NiO0.4 and ZnO0.4NiO0.6) binary nanocomposites were synthesized by hydrothermal technique. The binary nanocomposites were analyzed by UV-Visible spectrophotometer, X-ray diffraction (XRD), photoluminescence (PL), Fourier transform infrared spectrophotometer (FTIR), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The XRD pattern revealed that the nanocomposites, the peaks of both ZnO and NiO are present indicating the presence of both crystal structures hexagonal wurtzite and cubic. The miller indices, crystallite size, microstrain and dislocation density were determined from the XRD plot. FESEM and TEM analyses showed the spherical morphology of the synthesized composites with an approximate size of 10[Formula: see text]nm. The detailed analysis of ZnO–NiO binary nanocomposite sensor characteristics in terms of sensitivity, selectivity, response and recovery time were carried out and the nanocomposites were found to be highly sensitive to CO2 100 ppm at 350∘C and Cl2 at 200∘C. The photocatalytic degradation outcome showed 52% degradation of methylene blue at 10 ppm and 90[Formula: see text]w/m2. These results suggest the potential utility of these binary nanocomposites in photocatalytic applications for the degradation of organic pollutants.

Mixed matrix membranes incorporated with small pore zeolite UZM-5 for enhanced CO2/CH4 separation

Mixed matrix membranes (MMMs), which is polymeric matrix incorporated with inorganic filler materials, appear to be potential candidate for CO2 separation. Current work focuses on fabrication of MMMs incorporated with varying loading of small pore zeolite UZM-5 and modified UZM-5 for CO2/CH4 separation. Zeolite UZM-5 was firstly synthesized and then modified by using 3-aminopropyltriethoxysilane (APTES). MMMs was fabricated by incorporating zeolite UZM-5 and modified UZM-5 (NH2-UZM-5) into polysulfone (PSF) matrix. Both modified and unmodified zeolite UZM-5 were characterized via Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Field Emission Scanning Electron Microscope (FESEM) and Brunauer-Emmett-Teller (BET) analysis. The fabricated membranes were characterized using FTIR, XRD, TGA and FESEM analysis. The successful synthesis of zeolite UZM-5 was proven by XRD analysis. FESEM analysis of the membranes revealed that the successful the MMMs were successfully fabricated with even distribution of zeolites in the polymer matrix. In CO2 and CH4 gas permeation and separation study for the membranes, the highest CO2/CH4 ideal selectivity of 33.1 was obtained by the MMMs with 1 % NH2-UZM-5, which was a significant enhancement of 212 % in CO2/CH4 ideal selectivity as compared to the pristine PSF membrane.

Unveiling the structural, optical, electrical, and ferromagnetic properties of Ca2+ doped mixed spinel ferrites for switching field high-frequency device applications

In this paper, the calcium-doped nickel-zinc nano-ferrites [Ni0.5Zn0.5CaxFe2-xO4; x = 0.00, 0.10, and 0.30] were prepared using the chemical co-precipitation synthesis route and studied for switching field high-frequency device applications. The structural analysis has been completed by analyzing X-ray diffraction (XRD) patterns. The Rietveld refined XRD patterns confirmed the formation of cubic spinel structure of Ca2+ substituted nickel-zinc ferrites. The detection of metal-oxygen bonds present at A and B lattice sites has been unveiled by Fourier transform infrared (FTIR) spectroscopy. The morphological studies obtained through FESEM (Field emission scanning electron microscopy) analysis showed a reduction in the particle size from 70 nm to 53 nm when the concentration of Ca2+ ions in Ni-Zn ferrites was increased. Energy dispersive spectra (EDS) confirmed the presence of elements present in the prepared composition. The structure of a cubic spinel-shaped unit cell has been verified from three active prominent Raman modes (A1g, A2g, and T2g). Diffuse-reflectance spectroscopy (DRS) exhibits the increment in the bandgap values (from 1.55 eV to 1.63 eV) which helps fabricate highly efficient photovoltaic devices. The ferroelectric measurements yielded a rise in polarization values from 1.461 μC/cm2 to 18.228 μC/cm2 for 10 % Ca2+ ion substitution. The tangent loss values declined from 24 to 3 in Ni-Zn ferrites upon substituting Ca2+ ions. The Vibrating sample Magnetometer (VSM) technique found the increment in the saturation magnetization (Ms) values from 34.724 emu/g to 54.662 emu/g on substituting up to 30 % Ca2+ ions in Ni-Zn ferrites. These obtained results support the material in switching field distribution for high-frequency applications. The results exhibited that the prepared samples can be applicable for switching devices, filters, and microwave absorption devices. The results revealed the maximum frequency between 12 and 18 GHz which is useful for Ku band absorption.

Structural and Electrical Studies of Polycrystalline Pr𝑥Y1−𝑥FeO3 Materials Prepared Through Sol-Gel Route

Objectives: Investigations on structural, morphological and electrical studies of Pr substituted YFeO3 samples synthesized through sol-gel route are presented in this paper. Methods: PrxY1-xFeO3 (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) samples are synthesized by sol-gel auto combustion method. Structural characterization of the samples is done by using X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM) and Energy dispersive X-ray (EDX) techniques. Electrical properties are studied by J-E and Ln J-Ln E measurements. Findings: Rietveld refined XRD structural analysis shows sharp intense peaks indicating the crystalline nature of the samples and all the samples possess distorted orthorhombic structure with space group Pbnm. FESEM analysis shows non-uniform nature of grain size with increasing porosity. EDX data confirms elemental composition, weight and atomic percentage of the prepared samples which further confirms their purity. The leakage current density increases with increase in Pr doping. The slopes of Ln J-Ln E graphs of all the samples are in the range of 1.11 to 1.51 confirming that Ohmic conduction is predominant conduction mechanism. Novelty: Investigations on the effect of Pr substitution on electrical properties of single phase YFeO3­ samples reveal that the substitution of Pr in YFeO3 decreases the ferroelectric nature of the samples. Keywords: Sol-gel method, XRD, FESEM, EDX, Electrical Properties

Synthesis and Characterization of Gold Nanoparticles and Gold Nanoparticles Loaded with Bromelain

The production and use of nanometallic elements, such as gold, have received a lot of attention lately due to their distinctive features and wide range of uses. Most of these studies have employed the Turkevich approach. This research employed the Turkevich technique to produce gold nanoparticles (AuNPs). AuNPs and bromelain-loaded AuNPs were characterised using a variety of methods, including ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and zeta potential (ZP) measurements. The UV-Vis spectra of Bromelain, AuNPs, and AuNPs-Bromelain each had a peak at 276, 534, and 550 nm wavelengths, respectively. The FE-SEM and TEM studies revealed the presence of spherical particles with a smooth surface. The diameters of the AuNPs ranged from 49.32 to 77.29 nm; the diameters of the Bromelain-AuNPs ranged from 46.39 to 75.66 nm, as determined by the FE-SEM analysis. The TEM analysis indicated that the particles' sizes ranged from 7.40 to 15 nm for AuNPs and 14.51 nm for AuNPs-Bromelain. The XRD patterns revealed numerous diffraction peaks, indicating the crystal structure of the synthesised nanoparticles. FTIR spectrometry was employed to identify the functional groups in the synthesised nanoparticles. Zeta potential (ZP) measurements revealed that AuNPs had a zeta potential value of +0.1±0.4, and the zeta potential value for AuNPs-Bromelain was +1.2±3.0 mV.

Influence of Ni substitution on Structural, Optical, magnetic and transport properties of Mn0.5-xNixZn0.4Cu0.1Fe1.95Al0.05O4

A series of spinel ferrites Mn0.5-xNixZn0.4Cu0.1Fe1.95Al0.05O4 have been prepared by auto-combustion technique. X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) have been used for structural and morphological investigations. The XRD patterns confirm the formation of cubic spinel structure of ferrites. The lattice constants decrease with the increase of Ni contents due to the smaller ionic radii of Ni2+ compared to Mn2+ as well as particle size decreases. Density is increased and porosity is decreased with the increase of Ni contents in the samples due to the higher atomic weight of Ni2+ compared to Mn2+. The FESEM analysis reveal that the average size of the irregularly shaped grains increased with Ni contents. The mixed spinel structure is further confirmed by the FTIR spectra, which show a doublet band at about 600 cm−1. The observed optical band gap and the particle size variations are comparable, and the quantum size effect supports this conclusion. The real part of initial permeability and relative quality factor increase with the increase of Ni contents due to increase of density and grain size as well as decrease of porosity. Also, it is found that magnetic loss decreased with the increase of Ni contents. All the samples exhibit ferrimagnetic behavior and the number of Bohr magneton has been calculated for all compositions. The dielectric constant shows large value in the lower frequencies and decreases with frequency shows dispersion due to Maxwell-Wagner space charge polarization. The investigation of electric modulus has demonstrated the existence of the hopping conduction mechanism. The AC conductivity is very low at lower frequency region and very large at higher frequency region which can be explain according to the polaron hopping model of Austin and Mott. The AC conductivity enhances nearly linearly with frequency, suggesting that the mechanism of conduction is due to small polaron hopping, which can be described according to Jonscher’s power law. Also, the effect of grain and grain boundary resistance on transport properties has been investigated using complex impedance analysis and it has been observed that both exhibit an increase trend as the Ni content increases.

Analysis of fiber post–resin cement interfacial adaptation at different post regions using field emission scanning electron microscopy

Abstract Introduction: An ideal interfacial adaptation between fiber posts and resin cement is critical for optimum retention and good scenario. Therefore, this research was designed to estimate the interfacial adaptation at fiber post–resin cement interfaces using field emission scanning electron microscopy (FESEM) investigation. Materials and Methods: Forty-five extracted human lower premolars with sole and round canal were classified into three groups (n = 15) following the fiber post types. Each tooth was decoronated and implanted in acrylic resin-filled polyvinyl chloride mold. Roots were undergone endodontic management and post space preparations. Then, each group was classified into three subdivisions (n = 5) according to the resin cement types. After cementation, each post space was marked into apical, middle, and coronal thirds and sectioned horizontally into three 2 mm disc thickness for each third. After that, each disc in each sub-group was then subjected to FESEM analysis to evaluate the gaps width at fiber post–resin cement interface in µm. The data were recorded and statistically evaluated and compared using two-way analysis of variance and Duncan’s multiple range tests at P ≤ 0.05. Results: The everStick post with the RelyX U-200 cement group showed significantly the least gap width mean, while the glass fiber post with the TOTAL C-RAM cement has statistically the greatest gap width mean along the coronal, middle, and apical thirds of fiber post at P ≤ 0.05. The apical third of fiber post showed significantly the greatest mean of gap width, while the middle third showed the least gap width mean at P ≤ 0.05. Conclusion: Different brands of fiber post and resin cement can influence the interfacial adaptation at post–cement interface.

Investigating the effect of gliding discharge plasma on polystyrene and Polyamide6 by positron annihilation lifetime spectroscopy

Polymers are widely used today and the changes in their properties are investigated by different methods such as plasma irradiation. One of the most important methods for modifying polymers is cold plasma, by which the surface properties of the polymers can be changed under atmospheric pressure. In this study, the effect of plasma on Polystyrene (PS) and Polyamide 6 (PA6) samples was investigated. Surface and depth changes of the PS and PA6 have been investigated by various experimental techniques such as Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Contact Angle (CA), and Positron Annihilation Lifetime Spectroscopy (PALS). The results of Attenuated Total Reflectance (ATR)-FTIR show that the chemical bonds of PA6 have been changed, and preserved in PS in the depths. The XRD results show that there are no volume changes for chemical bands. The FESEM analysis results reveal that the plasma causes digging and creates roughness on the surface. The CA measurement confirms the FESEM results and points out an increase in hydrophobicity after plasma processing. The PALS results indicate that the free volumes of the matter are changed after plasma irradiation in the depths of PS and PA6. In addition, the plasma also causes changes in the micrometer depth.

Deposition of TiO2/Polymethylene Biguanide on Stainless Steel Wire for the Enhancement of Corrosion Resistance and Stability

Background: Orthodontic treatment relies on stainless steel (SS) wires to apply forces and torque to reposition teeth. However, SS wires are susceptible to wear and corrosion in the oral environment, necessitating improvements in their durability. Objective: This study explores the potential of a coating comprising titanium dioxide (TiO2) and polymethylene biguanide (PHMB) to enhance the corrosion resistance of SS wires. Methods: SS wires were coated with a solution containing PHMB and TiO2 using a drop-casting technique. Field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX), and electrochemical tests, including impedance spectroscopy and potentiodynamic polarization, were conducted to characterize the coated wires and evaluate their corrosion resistance. Results: FE-SEM, EDAX, and Emap analysis confirmed the presence and uniform deposition of PHMB/TiO2 onto the SS wire surface. Electrochemical tests revealed that the PHMB/TiO2- coated SS wires exhibited a significantly lower corrosion rate (7.08×10−6 mm/year) and higher corrosion resistance (562466 Ω) compared to bare SS. Conclusion: The PHMB/TiO2 coated SS wire exhibited high corrosion resistance and offered potential benefits for orthodontic treatments. Further research and optimization of this coating may help to improve the durability and reliability of orthodontic appliances.

Electrocoating of polyaniline on graphite carbon and activated carbon cloth surfaces as an anode and its effect on performance of microbial fuel cell

AbstractMicrobial fuel cell (MFC) is a bioelectrochemical‐based reactor that can generate electrical energy directly from wastewater by utilizing microbial activity that oxidizes the waste organic matter. This study aims to synthesize polyaniline (PANI) and deposit on a graphite carbon electrode (GCE) and activated carbon cloth (ACC) surface to use as an anode material for MFCs. The MFC performance was evaluated using oxygen and ferricyanide as electron acceptors. PANI was electropolymerized from its aniline monomer and deposited using an electrophoretic deposition method onto the electrode surface. A PANI thin film was characterized using FTIR, field emission scanning electron microscopy (FESEM), BET, and electrochemical analysis. The analysis results show the characteristic peaks of PANI at 1557 cm−1, demonstratinjg the existence of quinoid rings (NQN), while the peaks at 1479 and 1400 cm−1 corresponding to the benzenoid (NBN) stretching in the PANI structure. The FESEM analysis confirmed that PANI appeared to have a porous structure on modified electrodes. It was found that the best system was MFC with ferricyanide as the electron acceptor. The highest power density produced is 254 mWm−2 from GCE‐PANI and 16.47 mWm−2 from ACC‐PANI. The normalized energy recovery of GCE‐PANI and ACC‐PANI in ferricyanide is 0.115 kWh kgCOD−1 and 5.67 × 10−3 kWh kgCOD−1, respectively. The COD removal was observed to be 88.8% for GCE‐PANI and 87.2% for ACC‐PANI from 1000 mg/L COD.

The Surface Deterioration of Prefabricated Zirconia Crowns on Exposure to Acidulated Phosphate Fluoride Gel: An In Vitro Study.

Introduction Zirconia is a widely used restorative material in dentistry due to its superior aesthetic and mechanical properties. The oral cavity is a complex ecosystem with various components, which affect the teeth, as well as artificial restorative materials. Various personal and professional interventions carried out can severely affect the properties of restorative materials, thus altering the longevity of the prosthesis; 1.23% acidulated phosphate fluoride (APF) gel is one such professionally applied topical fluoride agent used to prevent caries. The interaction of this APF gel with highly aesthetic restorative material such as zirconia crowns is unknown. Objective The objective of this study is the evaluation of the surface deterioration of prefabricated zirconia crowns on exposure to deionised water and 1.23% acidulated phosphate fluoride (APF) gel with field emission scanning electron microscope (FE-SEM) and mass loss analysis. Material and method Sixty prefabricated paediatric zirconia crowns were taken, 10 samples were immersed in deionised water, 40 samples were immersed in 1.23% APF gel and 10 samples were used ascontrol. Surface morphology and mass loss analysis were carried out at time intervals of four minutes, 24 hours, 48 hours and 72 hours using FE-SEM and digital weighing machine. Results No visual change was observed in the samples immersed in deionised water at the time interval of 72 hours. There was a marked visual change in samples immersed in 1.23% APF gel at the time interval of four minutes to 72 hours; this change involved a loss of gloss to the appearance of chalkiness. FE-SEM analysis for the control group and samples immersed in deionised water showed a smooth, continuous, undisrupted top layer, while samples immersed in 1.23% APF gel showed changes ranging from surface etching, to pinhole porosities, to crack formation and disruption of the surface depending upon the exposure time. Conclusions On the immersion of zirconia crowns in an aqueous acidic medium of 1.23% APF gel, the crowns showed flaws, imperfectionsand uneven superficial layers. It has been observed that surface grains are disrupted and micropores have been formed. This degraded superficial surface when undergoes cyclic mechanical loading can accelerate the ageing phenomenon of zirconia. Mechanical forces along with a dynamic electrochemical environment can degrade the material properties of zirconia.