Field Emission Scanning Electron Microscopy Research Articles

The Identification of Microstructural Changes in High-Temperature Superconducting Tapes for Superconducting Fault Current Limiters

HTS 2G tapes used in Superconducting Fault Current Limiters (SFCLs) have properties that allow for the effective limitation of short-circuit currents; however, due to the specificity of the device operation, they should be characterized by the high stability of the parameters when repeatedly leaving the superconducting state. During the operation of SFCLs, a situation may occur in which the parameters of the HTS tapes used will change several times as a result of the action of short-circuit currents that exceed the critical current IC of the superconductor of the tape used. This paper presents the results of microstructural tests of 2G HTS tapes intended for SFCLs, subjected to surge currents corresponding to prospective short-circuit currents with values higher than their critical currents IC and for which IC changes were observed. The HTS tapes were examined using a JEOL 7600F field emission scanning electron microscope (SEM), and their chemical composition was analyzed using Energy-Dispersive X-ray Spectroscopy (EDS). The test results indicate the possibility of micro-damage in the form of cracks in the superconductor layer, as well as the interruption of the buffer layers and the oxidation of the silver layers. The analysis of the chemical composition of the HTS tape layers may indicate the occurrence of diffusion processes.

Optimization of deposition time on structural, morphological, and optical properties of Cd1-xZnxS nanocrystalline thin films

In this work, Cd1-xZnxS nanocrystalline thin films have been synthesized over a glass substrate by a simple and cost-effective Chemical Bath Deposition (CBD) technique at various deposition time keeping other deposition parameters constant. The structural, morphological, and optical properties are studied by incorporating a range of characterization techniques, including X-ray diffraction (XRD), Field Emission Scanning Electron Microscopes (FESEM), Energy Dispersive X-rays (EDX), and UV–Visible spectrophotometers (UV–Vis). The films have been deposited at five different deposition time in the range from 30 mins to 150 mins to record the changes which address in depth the structural, morphological and optical properties. Empirical fitting equations have also been developed to obtain a more quantitative analysis of the effect of deposition time. The results obtained in this work are compared with some recent reported works for performance analysis of the buffer layer. The proposed buffer layer deposited at 30 mins not only attains all the desirable qualities required for maximum extraction of solar energy but also a low-cost and environment friendly option, making it a potential candidate for solar cell and optoelectronic applications.

Electro-discharge deposition of zinc powder on 316L stainless steel: Synthesis, deposition rate, and characterization

This study investigated the potential of powder-mixed electrical discharge machining (PM-EDM) to deposit metallic powder, specifically zinc powder, on 316L stainless steel (316L SS). This study aimed to evaluate the effect of zinc (Zn) deposition on 316L SS for oil and gas application. Minitab 19 software was employed to design the experiments using screening DOE option and to analyse and model the results through screening response optimiser from Minitab 19 software. Surface morphology, microstructure and coating thickness were examined through field-emission scanning electron microscopy (FESEM) and scanning electron microscope (SEM). The results suggested an improvement in the coating thickness with an increase in powder concentration and discharge current. An average coating thickness of 91.47 μm was achieved in samples fabricated at 20 g/L powder concentration. X-ray diffraction analysis revealed the formation of hard carbides, such as Cr3C2 and TiC, on the PM-EDMed 316L SS surface. Further characterisation through energy-dispersive X-ray spectroscopy confirmed the deposition of both the tool electrode and Zn powder particles. The adhesion test confirmed that all specimens failed under 100% adhesive failure. The hydrophobicity analysis confirmed that the coated surfaces are hydrophobic. Significant improvement has been established for microhardness, wear resistance and corrosion performance. Screening results revealed that discharge current, pulse-on time, and powder concentration were the most significant parameters. The average predicted errors of 2.055%, 6.782%, and 2.396% for material deposition rate, tool wear rate, and surface roughness were achieved, respectively. These affirmed the excellent reproducibility of the model developed. This study presents a methodology for the formation of carbide- and oxide-based coatings specifically for oil and gas applications (flanges and connectors).

Characterization and Antibacterial Activity of Silver Nanoparticles Synthesized from Oxya chinensis sinuosa (Grasshopper) Extract.

In this study, silver nanoparticles (AgNPs) were synthesized using a green method from an extract of the edible insect Oxya chinensis sinuosa (O_extract). The formation of AgNPs (O_AgNPs) was confirmed via UV-vis spectroscopy, and their stability was assessed using Turbiscan analysis. The size and morphology of the synthesized particles were characterized using transmission electron microscopy and field-emission scanning electron microscopy. Dynamic light scattering and zeta potential analyses further confirmed the size distribution and dispersion stability of the particles. The average particle size was 111.8 ± 1.5 nm, indicating relatively high stability. The synthesized O_AgNPs were further characterized using X-ray photoelectron spectroscopy (XPS), high-resolution X-ray diffraction (HR-XRD), and Fourier transform infrared (FTIR) spectroscopy. XPS analysis confirmed the chemical composition of the O_AgNP surface, whereas HR-XRD confirmed its crystallinity. FTIR analysis suggested that the O_extract plays a crucial role in the synthesis process. The antibacterial activity of the O_AgNPs was demonstrated using a disk diffusion assay, which revealed effective activity against common foodborne pathogens, including Salmonella Typhimurium, Escherichia coli, Staphylococcus aureus, and Bacillus cereus. O_AgNPs exhibited clear antibacterial activity, with inhibition zones of 15.08 ± 0.45 mm for S. Typhimurium, 15.03 ± 0.15 mm for E. coli, 15.24 ± 0.66 mm for S. aureus, and 13.30 ± 0.16 mm for B. cereus. These findings suggest that the O_AgNPs synthesized from the O_extract have potential for use as antibacterial agents against foodborne bacteria.

Synthesis and assessment of the Mo/MoO3/CZTS/Ag diode fabricated by one-pot hydrothermal route: impact of temperature

A facile one-step hydrothermal method was utilized to prepare Cu2ZnSnS4 film employing EDTA as a complexing agent. An effective Molybdenum oxide layer was also formed in the same approach for forming the Cu2ZnSnS4 film. The influence of preparation temperature on structural, morphology, and optical characteristics was studied. The formation of crystalline kesterite phase Cu2ZnSnS4 films with preferred orientation along the (112) plane was confirmed by X-ray diffraction and Raman spectroscopy, and it was also demonstrated that structure property changes with preparation temperatures: kesterite phase Cu2ZnSnS4 is formed at lower preparation temperatures and kesterite phase Cu2ZnSnS4 and Cu2S are formed with increasing preparation temperature. Also, Raman analysis confirmed the formation of a Molybdenum oxide layer on the Mo substrate. Field emission scanning electron microscopy revealed that surface morphology changes from leaves of trees to flake-flowers. According to UV-visible analysis, Cu2ZnSnS4 films exhibited high and wide absorbance spectra in the visible and infrared regions and a band gap between (1.67-1.9) eV. Photoluminescence analysis revealed emission peaks at (1.569, 1.55, and 1.56) eV for samples prepared at (160, 200, and 230)0C, respectively, which is very close to the band's gap of Cu2ZnSnS4. Finally, the electrical study of Mo/MoO3/CZTS/Ag junctions was performed by using current-voltage (I-V) measurement.

Energy–dependent femtosecond LIPSS on germanium and application in explosives sensing

Abstract In this study, we fabricated laser-induced periodic surface structures (LIPSS) on a germanium surface through laser ablation in air using axicon and femtosecond (fs) pulses. This novel approach permitted the nanoscale material processing outcome refinement via an fs Bessel beam. Our investigations aimed at systematically understanding the formation of periodic structures under various experimental conditions, such as (i) different pulse energies ranging from 50 µJ to 1000 µJ at a constant scan speed and (ii) constant energy with different scan speeds (0.1–3 mm s−1). By adjusting the fluences and scan speeds, we were able to identify the parametric space and alter the periodicity of the low-spatial frequency LIPSS and high-spatial frequency LIPSS on germanium, which were analyzed using field emission scanning electron microscopy. An optimal LIPSS formation over a large area of germanium was achieved at an input energy of 250 µJ and a scan speed of 0.75 mm s−1. Additionally, we measured the contact angles of the Ge nanostructures (GeNSs) to demonstrate their hydrophobic nature and non-wetting properties, providing insights into the behavior of LIPSS. Subsequently, the GeNSs were coated with a ∼15 nm thick gold (Au) film using a thermal deposition method. Utilizing these, the surface-enhanced Raman spectroscopy (SERS) technique detected diverse analytes, such as tetryl (an explosive) at a concentration of 50 µM and thiram (a pesticide) at 500 nM. The SERS enhancement factors for tetryl and thiram molecules on GeNSs coated with a 15 nm-thick Au layer were determined to be 2.5 × 104 and 4.2 × 105, respectively.

Rapid Microwave Annealing for Improved Crystallinity and Morphology of Perovskite Materials

Perovskite solar cells are gaining significant attention for their remarkable power conversion efficiency, cost‐effective processing, and material abundance. This study investigates the impact of rapid microwave annealing on the crystallinity and morphology of MAPbI3 films on FTO glass substrates. Multifaceted characterization techniques, including field emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), UV–Vis spectroscopy, photothermal deflection spectroscopy (PDS), and steady‐state photoluminescence (PL) measurements are used to compare microwave‐annealed samples with traditional hotplate‐annealed samples. Microwave annealing yields significantly larger crystals in shorter processing times, suggesting enhanced crystallinity, as evidenced by SEM analysis and XRD data. UV‐Vis and PDS measurements indicate improved optical properties and reduced sub‐bandgap states, while PL results suggest diminished nonradiative recombination in microwave‐annealed samples. However, a partial film detachment has been observed at higher microwave powers, a phenomenon explained by COMSOL simulations. These findings demonstrate rapid microwave annealing as an energy‐efficient and cost‐effective alternative while highlighting the need for further optimization to address film degradation issues, which remain a significant challenge. This research supports the potential for scalable, high‐quality perovskite material production, facilitating large‐scale production and commercialization of next‐generation solar cells.

Next-Generation BiOCl/MXene Nanocomposites: Optimized for Dye Removal and Supercapacitor Applications.

The study focuses on the development of an efficient and sustainable solution for synthetic dye degradation through the hydrothermal synthesis of BiOCl and BiOCl/MXene heterostructures. Structural and compositional properties were analyzed by using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS) techniques. A significant reduction in the band gap of BiOCl/MXene to 2.97 eV from 3.62 eV for BiOCl was observed via UV spectroscopy, leading to enhanced photocatalysis with 89% degradation efficiency in just 12 min. The mechanism involved and reactive species were confirmed by LC-HRMS and radical trapping tests, while ICP-MS verified metal content in water before and after degradation. Additionally, the nanocomposite demonstrated a specific capacitance of 431.24 F g-1 at a current density of 1 mA cm-2, with an excellent capacitance retention of 94.35% after 2000 cycles. This study highlights BiOCl/MXene as a promising material for both photodegradation and supercapacitor applications.

Microstructural and biological characterization of 3D printed PEEK scaffolds coated with alginate/CNT for bone regeneration applications

The main aim of bone tissue engineering is to develop novel scaffold structures that integrate biological functionality with sufficient mechanical strength and properties. In this study, bone scaffolds were fabricated using polyether ether ketone (PEEK) via 3D printing, resulting in three different porous designs. To enhance their biological attributes, these scaffolds were coated with an alginate and carbon nanotube (CNT) composite using a freeze-drying technique. The biological characteristics of fabricated samples, such as biocompatibility and bioactivity, were evaluated in simulated body fluid (SBF). Field emission scanning electron microscopy (FE-SEM) analysis showed that the 3D-printed PEEK scaffolds had a porous, uniform, and interconnected architecture with pore sizes between 321–378 µm. Energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) confirmed the formation of hydroxyapatite (HA) and bioactive calcium phosphate (Ca-P) on the scaffold surfaces, indicating their bioactivity. Cell biocompatibility was assessed using the MTT assay, which revealed a high cell viability rate of approximately 97% and no significant toxicity. Consequently, the 3D-printed PEEK scaffold coated with Alginate/0.3%wt CNT demonstrated promising microstructure, bioactivity, and biocompatibility, making it suitable for bone tissue regeneration.Graphical abstract

Synthesis and Characterization of cellulose-derived superabsorbent hydrogel and its applications in the treatment of wastewater containing heavy metal ions

A cellulose xanthate (CX) based polymer hydrogel has been synthesized using free radical graft polymerization technique. Two monomers Acrylic Acid (AA) and Acrylonitrile (AN) were reacted with cellulose xanthate to synthesize the desired hydrogel CX-g-poly(AA-co-AN). The synthesized hydrogel has been characterized by various techniques viz. Thermo-gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV), Field emission scanning electron microscope (FESEM) and Point zero charge (PZC). This hydrogel has been employed for the removal of toxic metal ions from wastewater. The maximum percentage removal has been found to be 97.5 (±4.87)% for Cu2+ ions and 96.1 (±4.80)% for Co2+ ions under optimum pH 6. The calculated adsorption capacities have been found to be 330.03 (±35.3) mg/g for Cu2+ ions and 325.73 (±22.4) mg/g for Co2+ ions using the Langmuir Adsorption isotherm model. The thermodynamic parameters depicted that the process was endothermic, and spontaneous. The adsorption kinetics data shows excellent fit with pseudo-second-order kinetic model. The synthesized hydrogel exhibits a high swelling ratio of 846.85 (±42.36) g/g and retention ratio of 50.12 (±2.50) % in distilled water. Also, the synthesized hydrogel showed good reusability, exhibiting percentage removal 83.2% for Cu2+ ions and 81.3% for Co2+ ions in the fifth cycle.

Enhanced lead adsorption by eco-hydroxyapatite derived from marble sludge: Optimization and kinetic study

In this study, eco-hydroxyapatite (e-HAP) was synthesized from marble sludge via a hydrothermal process for utilization as an adsorbent in the removal of Pb2+ ions from wastewater. X-ray powder diffraction (XRD) and thermal field emission scanning electron microscope (FE-SEM) revealed that increasing the Ca/P molar ratio (CPMR) and hydrothermal temperature (HT) increased crystallinity and that the influence of HT was more apparent. An increase in crystallinity, crystal length, and peak intensity was observed following an increase in the CPMR. Adsorption studies show that when the HT was 393 K, the CPMR was 0.67, the initial Pb2+ ion concentration was 100 mg/L, the equilibrium time was 20 min, and the adsorbent dosage was 0.6 g/L. The resulting removal efficiency (99.99 %) and maximum adsorption capacity (166.65 mg/g) are both very high. Adsorption kinetics are well described using a pseudo-second-order kinetic model. This paper presents a facile and economically sustainable approach to the synthesis of e-HAP from marble sludge for use in removing of Pb2+ from wastewater.

Covalent Lysozyme Immobilization on Enzymatic Cellulose Nanocrystals.

Nanostructured materials represent promising substrates for biocatalyst immobilization and activation. Cellulose nanocrystals (CNCs), accessible from waste and/or renewable sources, are sustainable and biodegradable, show high specific surface area for anchoring a high number of enzymatic units, and high thermal and mechanical stability. In this work, we present a holistic enzyme-based approach to functional antibacterial materials by bioconjugation between the lysozyme from chicken egg white and enzymatic cellulose nanocrystals. The neutral CNCs were prepared by endoglucanase hydrolysis from Avicel. We explore the covalent immobilization of lysozyme on enzymatic CNCs and on their TEMPO oxidized derivatives (TO-CNCs), comparing immobilization yields, material properties, and enzymatic activities. The materials were characterized by X-ray diffractometry (XRD), attenuated total reflectance Fourier Transform infrared spectroscopy (ATR-FTIR), bicinchoninic acid (BCA) assay, field-emission scanning electron microscopy (FE-SEM) and dynamic light scattering (DLS). We demonstrate the higher overall efficiency of the immobilization process carried out on TO-CNCs, based on the success of covalent bonding and on the stability of the isolated bioconjugates.

Magnetic structure and colossal dielectric properties in Ga3+ substituted Zn2Y hexaferrites by chemical co-precipitation method

Y-type Ba0.5Sr1.5Zn2Fe12-xGaxO22 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) hexaferrites are prepared through modified chemical co-precipitation method. X-ray diffraction (XRD) results reveal that these samples are single-phase and the space group is R3‾m. The field-emission scanning electronic microscope (FE-SEM) measurements indicate that the grains are hexagonal-plate with a diameter of 2–5 μm. In the M-T diagrams, various magnetic structures are modulated, including proper-screw, longitudinal conical (LC), mixed conical (MC), and collinear ferrimagnetic (collinear FIM). In this series of samples, the values of dielectric constant (ε′) achieve an order increase from 102 to 104. For the best x = 0.8 sample, the ε′ is as high as 1804.76 at 1 MHz and 300 K. In conclusion, Ba0.5Sr1.5Zn2Fe12-xGaxO22 with controllable magnetic structures and colossal dielectric constant are potential materials for miniaturization of modern electronic devices.

Enhancing Herbal Efficacy: Synthesis and Evaluation of Nanosuspension from Withania somnifera Root Extract

Background: Ayurveda emphasizes the balance of mind, body, and spirit, drawing on ancient texts that highlight the medicinal properties of herbs like Withania somnifera, known for its wide range of therapeutic applications and pharmacological benefits. Commonly referred to as Indian ginseng or Ashwagandha, Withania somnifera, demonstrates a variety of therapeutic effect , including anti-inflammatory, antitumor, sedative, hypnotic, deobstruent effects, narcotic, antioxidant, tonic, antistress, diuretic, aphrodisiac, immunomodulatory, and rejuvenating properties. Nanotechnology, particularly through the development of nanosuspensions, offers a significant advancement in medicine, addressing challenges like poor solubility and low bioavailability of lipophilic drugs. Nanosuspensions can enhance drug safety and efficacy by improving solubility and altering pharmacokinetics. Methods: This study focuses on formulating and characterizing a nanosuspension using an ethanolic extract of Withania somnifera roots. The nanosuspension (NSWS) underwent comprehensive characterization, utilizing techniques such as FT-IR spectroscopy, particle size analysis, zeta potential measurement, polydispersity index (PDI) assessment, Field emission scanning electron microscopy (FESEM), X-ray diffraction analysis, pH measurement, and stability testing. This study seeks to explore the potential of nanosuspensions, aiming to integrate nanotechnology with herbal medicine to improve the safety and efficacy of herbal formulations. Results: The nanosuspension (NSWS) shown particle size about 133.09 nm, and its uniform particle distribution was indicated by a Polydispersity Index (PDI) about 0.27. Stability and uniformity were further supported by the zeta potential, particle size, and PDI values. Conclusion: Nanosuspension formulations represents a versatile strategy to improve the therapeutic efficacy of hydrophobic drugs across various routes of administration. Keywords: Withania somnifera, Nanosuspension, Characterization, FT-IR, PDI, FESEM

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.

Enhancing sensitivity in wireless capacitive pressure sensors via highly flexible LC circuits utilizing porous polydimethylsiloxane dielectric layer

In this study, we introduce a highly flexible LC circuit-based wireless capacitive pressure sensor (CPS) that utilizes porous polydimethylsiloxane (PDMS) as a dielectric layer, demonstrating its transformative potential in tactile sensing, physiological monitoring, and flexible electronics. To optimize sensor performance, various porous PDMS thin films (100 μm) with different porosities (ranging from 0 % to 75 %) were prepared using a novel steaming method, and their properties were thoroughly analyzed using field emission scanning electron microscopy (FE-SEM) and capacitance measurements. Remarkably, the sensor with a 75 % porous PDMS film demonstrated enhanced sensitivity up to 11 times compared to the 0 % porous (pristine) PDMS film when subjected to a 300 g weight. High sensitivities of 0.046 kPa^-1, 0.036 kPa^-1, and 0.028 kPa^-1 were attained for the pressure sensor in the pressure ranges of 0–9.8 kPa, 0–19.6 kPa, and up to 29.4 kPa, respectively. Additionally, a real-time resonance frequency analysis was conducted using a network analyzer, allowing the detection of tiny pressure changes in an artificial blood vessel. Finally, the flexibility of the wireless CPS was investigated by studying various parameters, including body temperature, facial expressions such as smiling, selected speech characters (M, N, T, L), and swallowing actions.

Magneto-electrochemical water splitting performance of graphene oxide/nickel aluminum-layered double hydroxide nanocomposites

Designing efficient, cheap catalysts for oxygen production is very important for water electrolysis and green hydrogen production. Here, synthesis and electrocatalytic performance of graphene oxide (GO)/nickel-aluminum layered double hydroxide (NiAl-LDH) composites were investigated for water-splitting applications. The composition, microstructure, and morphology of the nanocomposites were confirmed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FE-SEM), and their water oxidation performance was examined in 0.1 M potassium hydroxide solution in the presence and absence of magnetic field. The results show that optimized GO/NiAl-LDH nanocomposite (GO-1 %/NiAl-LDH) exhibits the lowest overpotential compared with other prepared nanocomposites. This performance demonstrates comparable electroactivity to well-developed electrocatalysts like the perovskite-based electrodes, it also shows an improved electrocatalytic activity compared to NiAl-LDHs due to the presence of graphene oxide in the composite. We interpreted this significant performance to improve electron transform and high active site at the synthesized GO/NiAl-LDH composites. The best electrocatalytic activity with an overpotential of 443 and 473 mV at the current density 10 mA.cm−2 were evidenced for GO-1 %/NiAl-LDH nanocomposite in the presence and absence of external magnetic field, respectively. Furthermore, the tafel slope were reported about 54 and 162 mV.dec−1 in the presence and absence of magnetic field, respectively. This improved water oxidation can be attributed to the magneto-hydrodynamic effect and the increased number of metal sites on LDHs under the magnetic field.

Enhanced wound healing with biogenic zinc oxide nanoparticle-incorporated carboxymethyl cellulose/polyvinylpyrrolidone nanocomposite hydrogels.

Contemporary wound dressings lack antibacterial properties, exhibit a low water vapour transmission rate, and demonstrate inadequate porosity. In order to overcome these limitations, scientists have employed water hyacinth to produce carboxymethyl cellulose (CMC). CMC/PVP nanocomposite films containing biogenic zinc oxide nanoparticles (nZnOs) were synthesised using cost effective solution-casting technique. As the proportion of nZnOs in the film increased, swelling and water permeability decreased, whereas mechanical stability improved. Dynamic light scattering testing and transmission electron microscopy confirmed that the particle size was around 50.7 nm. Field emission scanning electron microscopy (FESEM) images showed that nZnOs were distributed uniformly in the polymer matrix. Cell viability against Vero cells was greater than 94%, and a substantial zone of inhibition against S. aureus and E. coli bacteria was observed. Wounds of albino mice were treated with CMC/PVP and CMC/PVP/nZnO (6%) nanocomposite hydrogels and healed in 20 and 12 days, respectively, as demonstrated by wound healing assay and histological staining. In vitro and in vivo studies revealed that the novel nanocomposite hydrogels exhibit improved cell viability and wound healing features. Therefore, they could be exploited as promising skin wound dressing materials.

Energy band gap tuning of Ba-Ca hexagonal ferrite by Dy3+ ion substitution (0 ≤ x ≤ 0.2) to improve spectral, structural, dielectric and photocatalytic properties

In the present study, Dy3+ substituted M-type Ba0.5Ca0.5DyxFe12-xO19 (0.00 ≤ x ≤ 0.20) hexagonal ferrites were synthesized using sol-gel auto-combustion method with lemon extract as a fuel. The single hexaferrite phase with space group P63/mmc is revealed by the X-ray powder diffraction (XRD) patterns. The Field emission scanning electron microscopy (FESEM) exhibits the agglomeration of nanoplates with vacancies at some places. Energy dispersive X-ray photoelectron spectroscopy (EDAX) mapping confirmed the presence of Ba, Ca, Fe, O, and Dy in the hexaferrite. Fourier Transform Infrared (FTIR) spectroscopy exhibits two characteristic bands at 579 and 429 cm−1 corresponding to tetrahedral and octahedral metal ions-oxygen stretching, revealing the occurrence of the ferrite phase. The optical energy band gap calculated using the Tauc plots was found to increase with the increase in dysprosium substitution to fall within the range of 2.8–3.5 eV. The Raman spectra confirmed the Raman vibration modes and M-type structures of hexagonal ferrites (HFs). The dielectric constant values drop rapidly with increasing frequency up to a few KHz and then gradually for the further higher frequencies. The occurrence of Ba and Ca with 2+, while Dy, and Fe with 3+ oxidation states is confirmed using X-ray photoelectron spectroscopy (XPS). The HFs exhibit remarkable efficiency by degrading the Reactive Brown dye to 99.3 % in just 15 min, equivalent to a high degradation reaction rate constant (k) value of up to 0.0396 min−1. Consequently, the catalyst shows promising potential for environmental remediation.

A Machine Learning Assisted Non-Enzymatic Electrochemical Biosensor to Detect Urea Based on Multi-Walled Carbon Nanotube Functionalized with Copper Oxide Micro-Flowers.

Detecting urea is crucial for diagnosing related health conditions and ensuring timely medical intervention. The addition of machine learning (ML) technologies has completely changed the field of biochemical sensing, providing enhanced accuracy and reliability. In the present work, an ML-assisted screen-printed, flexible, electrochemical, non-enzymatic biosensor was proposed to quantify urea concentrations. For the detection of urea, the biosensor was modified with a multi-walled carbon nanotube-zinc oxide (MWCNT-ZnO) nanocomposite functionalized with copper oxide (CuO) micro-flowers (MFs). Further, the CuO-MFs were synthesized using a standard sol-gel approach, and the obtained particles were subjected to various characterization techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared (FTIR) spectroscopy. The sensor's performance for urea detection was evaluated by assessing the dependence of peak currents on analyte concentration using cyclic voltammetry (CV) at different scan rates of 50, 75, and 100 mV/s. The designed non-enzymatic biosensor showed an acceptable linear range of operation of 0.5-8 mM, and the limit of detection (LoD) observed was 78.479 nM, which is well aligned with the urea concentration found in human blood and exhibits a good sensitivity of 117.98 mA mM-1 cm-2. Additionally, different regression-based ML models were applied to determine CV parameters to predict urea concentrations experimentally. ML significantly improves the accuracy and reliability of screen-printed biosensors, enabling accurate predictions of urea levels. Finally, the combination of ML and biosensor design emphasizes not only the high sensitivity and accuracy of the sensor but also its potential for complex non-enzymatic urea detection applications. Future advancements in accurate biochemical sensing technologies are made possible by this strong and dependable methodology.