X-ray Spectroscopy Research Articles

Keratin-reinforced encapsulation of whole cells expressing glucose isomerase: Development of robust and reusable biocatalyst microbeads.

Glucose isomerase (GI) is crucial in high-fructose corn syrup production. This study introduces a novel approach to enhance GI stability and reusability through whole-cell encapsulation of Streptomyces olivochromogenes PTCC 1457 in hybrid microbeads, utilizing keratin as a multifunctional stabilizer and cross-linker. Optimal bead formation was achieved using 2% alginate, 2-3% CaCl2, and 2.5% keratin at pH7.0 and 37-40°C. Keratin played a vital role in forming a robust and flexible matrix. Immobilization in keratin-alginate-biomass beads maintained GI activity (655 GIU·g-1) comparable to free enzyme (650 GIU·g-1), while silicate incorporation reduced activity to 234 GIU·g-1. The immobilized enzyme exhibited enhanced stability over a wider pH (6-9) and temperature (4-60°C) range compared to the free enzyme. Importantly, the immobilized GI maintained 80% of its initial activity after 20 reaction cycles. Thermogravimetric analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and tensile testing confirmed the formation of hybrid beads with improved thermal and mechanical stability. This novel immobilization strategy, leveraging keratin's unique properties, offers a promising approach for enhancing GI stability, reusability, and storage longevity, potentially improving its industrial applicability in high-fructose corn syrup production.

Study of spectral features and depth distributions of boron layers on tungsten substrates by ps-LIBS in a vacuum environment

Boronization is used in present-devices as wall condition technique due to its effectiveness in reducing oxygen and other impurities in the vessel as well as improving plasma performance. The technique is also currently under consideration as wall conditioning method for the proposed full-tungsten (W) wall of the International Thermonuclear Experimental Reactor (ITER). However, the impact of the deposited Boron (B) layer thickness, and its homogeneity after the boronization process is uncertain as well as knowledge about the layer lifetime and improved conditions. In this study, an approach of the picosecond-laser-induced breakdown spectroscopy (ps-LIBS) is investigated to analyze the depth distribution of B-films on W-substrates by using three optical spectrometers in a vacuum environment. The depth distribution of two types of B-films on W-substrates with the thicknesses of 130 nm and 260 nm were sequentially measured under different laser spot sizes (varying the laser fluence). The B-films on the W-substrates were made by magnetron sputtering to simulate the thin B layers during the boronization. The measured average ablation rate of ps-LIBS shows a notable decrease with increasing laser spot size. Additionally, the spectral lines of B and W exhibit distinct intensity distributions under different spot sizes due to the different excitation thresholds of the B-films and the W-substrates. The interface between B-films and W-substrates, as well as the thickness of the B-films, were determined using the normalized intensity and intensity ratio method, respectively. The results from ps-LIBS measurements regarding the depth are in good agreement with those obtained through the Focused Ion Beam combined with Scanning Electron Microscopy (FIB-SEM) and Energy Dispersive X-ray Spectroscopy (EDS). These initial findings verify the feasibility to characterize the thickness and uniformity of thin B films in the order of 100 nm and below on W-substrates using ps-LIBS.

Approach to Design Sustainable Alkali-Activated Slag Recycled Aggregate Concrete: Mechanical and Microstructural Characterization

There is a steep increase in demand for concrete as the need for infrastructure is increasing with a rapid increase in urbanization. Consequently, there has been a surging demand for cement across the globe. By using alkaline concrete activated with ground granulated blast furnace slag (GGBS), cement usage can be eliminated in concrete, which addresses the issue of CO2 emissions concerned with the cement manufacturing process and promotes the use of industrial by-products as sustainable building materials. The current study focuses on proposing a methodology to design sustainable GGBS-based alkali-activated concrete incorporated with 100% coarse recycled coarse aggregates (RCA) recovered from construction and demolition (C&D), for various strengths by optimizing the mix proportions and verifying the same through experiments. From the current study, it is evident that this mix design procedure can be adopted to design alkali-activated slag recycled aggregate concrete (AASRAC) mixes for strengths ranging from 44MPa to 85MPa. The optimum values of alkalinity factor (λ) and NaOH concentration (M) i.e., 1.5 and 12, have a significant role in the development of high strengths which is attributed to the formation of hydrotalcite. Micrographs captured using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) studies reveal that the alkaline binders promote the development of a denser and stronger interfacial transition zone (ITZ) that enhances the strength of lower AA/B concretes at the microstructural level as Ca/Si ratio is higher for lower AA/B concretes. Global warming potential (GWP) analysis reveals that the alkali-activated concretes have significantly lower GWP compared to conventional OPC-based concrete by approximately 2.5 times. The mix-design chart proposed in this study may pave the way to designing structural grade AASRAC with enhanced performance for the desired strength, which may find its application in fast-track construction and manufacturing of prefabricated elements.

Biosynthesis of ZnO nanocomposites from Mentha spicata applications of antioxidant, antimicrobial and genotoxicity advances in MCF-7 cell line

This study focuses on enhancing the, Spearmint (Mentha spicata), an aromatic herb indigenous to Europe and Asia, which is valued for its refreshing flavor and potential health benefits. This herb is widely utilized in culinary practices, medicinal applications, and cosmetic formulations. The ethanol extract derived from the M. spicata leaf contains is rich secondary metabolites with various bioactive properties: Specifically, such as tannins, flavonoids, and polyphenols are known for their antioxidant and anti-inflammatory effects, saponins help reduce cholesterol, and alkaloids have analgesic properties. The extract has a total flavonoid content (TFC) of 231.37 ± 2.05 mg GAE/g and a total phenol content (TPC) of 247.32 ± 5.07 mg GAE/g. Zinc oxide (ZnO) nanoparticles were synthesized from this extract and subsequently characterized through various analytical techniques. The absorbance measurement at 437 nm confirmed the successful nanoparticle synthesis. FTIR spectra showed water-related absorption bands at 3330 cm−1 and 3337 cm−1. Scanning electron microscopy (SEM) indicated the presence of spherical nanoparticles of about 25.4 nm, while transmission electron microscopy (TEM) illustrated particles ranging from 20 to 50 nm with high crystallinity and a lattice spacing of 0.297 nm. X-ray diffraction (XRD) analysis confirmed their crystalline structure with distinct Bragg reflections at 39.1°, 46.1°, 68.7°, and 79.2°, which corresponding to (111), (200), (220,311) planes, respectively (JCPDS card no. 01–080-1876). Energy-dispersive X-ray spectroscopy (EDX) confirmed the high purity of the synthesized ZnO nanocrystals. The nanoparticles demonstrated significant antioxidant activity with radical scavenging rates up to 97.33 %, effective antimicrobial properties, and notable anticancer activity, achieving 99.75 % inhibition of MCF-7 cells at 40 μg/mL. These findings highlight the nanoparticles' potential applications in health and medicine.

Electrophoretic Deposition of Bioactive Glass 58S- xSi3N4 (0

This paper aims to investigate the biocompatibility, bioactivity and properties of bioactive glass 58S-xSi3N4 (0<x<20 wt.%) nanocomposite coating on AISI 316L stainless steel substrate, applied by electrophoretic deposition method. The implications of adding Si3N4 nanoparticles up to 20 wt.% to the bioactive glass coating for the structural and biomedical properties of deposited coatings were investigated. The deposited coating samples were characterized by X-ray diffraction (XRD) analysis, field emission scanning electron microscope (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDS). For the evaluation of cellular toxicity, the MTT cytotoxicity test with MG63 bone cell was performed. Bioactivity test was also conducted in simulated body fluid (SBF) up to 28 days. Results showed that increase in the Si3N4 content of composite samples is associated with a significant decrease in the average size of composite powder, inferring that Si3N4 additive has become nucleation sites during synthesis. Stereomicroscope images showed that with an increase in deposition time up to 70 min, a uniform coating can be attained. An increase in the Si3N4 content is associated with a significant reduction in surface roughness and non-uniformities of the deposited layer. The addition of Si3N4 in the composite layer slightly increases the wetting angle. The highest cellular toxicity was observed for the AISI 316L sample at the concentration of 10 micromolar, while the lowest cellular toxicity is attributed to the BG-20%Si3N4 sample at the concentration of 75 micromolar, exhibiting viability values similar to the control sample. Bioactivity assessment of deposited coatings indicated a remarkable improvement in the bone-forming ability of Si3N4-containing bioactive glass composite.

Non-Destructive Integration of Spark-Discharge Produced Gold Nanoparticles onto Laser-Scribed Graphene Electrodes for Advanced Electrochemical Sensing Applications

Gold nanoparticles (AuNPs) decorated graphene materials are preferable materials in a wide range of electrochemical applications, however, the current methods for preparing them have several limitations. Herein, we have developed a green, solution-free, and non-destructive method for the in-situ generation of AuNPs on laser-scribed graphene electrodes (LSGEs), addressing the limitations of traditional preparation methods. This novel technique, contrasting with the conventional solution-based electrochemical deposition, utilizes spark discharge to modify LSGEs, demonstrating superior performance in sensors and biosensors applications. Through comprehensive characterizations (scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Raman spectra, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Kelvin probe force microscopy (KPFM)), we observed significant distinctions in particle size, metal loading, stability, surface-to-volume ratio, and graphene quality between spark-discharge produced AuNPs (SP-AuNPs) and electrodeposition produced AuNPs (EC-AuNPs). The average particle sizes of the SP-AuNPs and EC-AuNPs are 10 nm and 38 nm, respectively. The SP-AuNPs modified LSGEs demonstrate exceptional electroanalytical performance in dopamine detection, with a broad detection range (0.6–90 µM) and low LOD (0.40 µM), further validated in human neuroblastoma cells SH-SY5Y. Our findings suggest that the spark discharge method represents a significant advancement in the synthesis of metal nanoparticle enhanced LSG electrodes, with broad implications for electrochemical sensing, biosensing, and biomedical applications.

Probabilistic-based identification of gunshot residues (GSR) using Laser-Induced Breakdown Spectroscopy (LIBS) and Support Vector Machine (SVM) algorithm

Firearm violence results in thousands of victims annually in Brazil, which is ascribed, among other factors, to the low homicide resolution rates. One method for generating forensic evidence in firearm discharges is the identification of gunshot residues (GSR), typically composed of inorganic particles containing primarily lead (Pb), barium (Ba), and antimony (Sb). The “gold standard” technique for GSR identification is Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDS) which is highly accurate but demands significant time and labor for each sample analysis. Other tests to detect GSR include the colorimetric rhodizonate test and spectroscopic techniques such as Laser-Induced Breakdown Spectroscopy (LIBS), which are quicker, but exhibit lower reliability and a higher potential for false positives and potentially compromise the investigation. This study introduces a novel GSR analytical protocol as a potential alternative to SEM-EDS and colorimetric tests, which is based on LIBS analysis combined with dimensionality reduction performed by PCA and probabilistic Support Vector Machine (SVM) algorithm. The developed protocol accurately predicts both positive and negative samples, and establishes the probability of each prediction, allowing for the exclusion of questionable samples from the analysis. The initial tests show the protocol achieved 100 % accuracy in both training and external validation. As a stress test, the protocol is able to exclude questionable samples from the analysis and accurately predict true samples with 100 % correct classifications from a set of artificially contaminated samples containing elements characteristic of GSR, highlighting the protocol’s significant reduction in the likelihood of false positives.

Innovative synthesis and practical application of graphitic carbon nitride/α-zirconium phosphate in visible light-activated Knoevenagel condensation

To advance the development of efficient photocatalysts activated by visible light for environmental applications. We employed a simple approach to synthesize g-C3N4/α-ZrP composite in different mass ratios, followed by comprehensive characterization through several techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope coupled with energy dispersive X-ray spectroscopy (SEM/EDS), and UV–Visible diffuse reflectance spectra (DRS). Furthermore, the g-C3N4/α-ZrP with mass ratio 6:1 was demonstrated high performance catalytic activity in Knoevenagel condensation (Yield 88 %–96 %) in a short reaction time (5–20 min) under visible light irradiation. The use of g-C3N4/α-ZrP has transformed the traditional synthesis of carbon–carbon double bonds, offering improved reaction rates and reduced by-products. These next-generation photocatalysts also exhibit remarkable properties that facilitate the activation of substrates under milder conditions, opening up new possibilities for green and sustainable synthesis. This advancement contributes to the development of environmentally friendly and efficient synthetic methodologies.

Synergistic Enhancement of 7075 Aluminum Alloy Composites via High Entropy Alloy Particle Integration: Microstructural and Mechanical Insights

This study investigates the impact of high-entropy alloy (HEA) particle reinforcement on the microstructure, mechanical properties, and performance of 7075 aluminum matrix composites (AMCs). Utilizing spark plasma sintering (SPS), composites with varying HEA particle concentrations were synthesized to assess their effects comprehensively. The results indicate that increasing HEA content significantly enhances the density and hardness of the composites. Specifically, a 20 wt% HEA reinforcement achieved a high hardness of 61 HRB and a density of 3.21 g/cm³. The compressive strength initially increased with HEA content but then decreased as it ranged from 5 wt% to 20 wt%. Optimal mechanical properties, including a compressive strength of 680 MPa and a fracture elongation of 33%, were observed at 10 wt% HEA. Wear testing further demonstrated the advantages of HEA reinforcement, with a substantial reduction in wear rate from 9.97±1.1×10⁻⁴ to 2.06±0.1×10⁻⁴ mm³/N·m at 10 wt% HEA. Additional analyses using energy-dispersive X-ray spectroscopy (EDX) and nanoindentation identified an aluminum-rich transition layer at the HEA-aluminum interface, formed due to aluminum diffusion. This transition layer likely enhances interfacial wettability and bonding, contributing to the improved performance of the composite.

Characterization of fuel cladding chemical interaction on a high burnup U-10Zr metallic fuel via electron energy loss spectroscopy enhanced by machine learning

Fuel cladding chemical interaction (FCCI) is one of the limiting factors for metallic fuels in nuclear application. A comprehensive analysis of chemical elements in FCCI is the basis for understanding the phenomena and developing potential mitigating strategies. The detection of low atomic number elements (Z < 11) and lanthanide fission products is challenging for energy dispersive x-ray spectroscopy (EDS). This work used scanning transmission electron microscopy (STEM) based electron energy loss spectroscopy (EELS) to study the distribution of carbon and lanthanides in the FCCI region of a solid U-10Zr (wt%) fuel irradiated to 13.2 at. % burnup at fast flux testing facility. Processing the EELS data involved three major steps: 1) enhancing the signal to noise ratio by denoising the spectrum using principal component analysis methods; 2) identification of chemical elements with core energy loss edges; 3) microstructural phase segmentation based on raw EELS spectrums using the K-means clustering method. EELS analysis revealed the formation of zirconium carbide, a rind-like microstructural phase in FCCI region between fuel and cladding. This rind appeared to be intact at this burnup. The study also revealed the shift of plasmon peak between zirconium and zirconium carbide. The EELS mapping also indicated a different distribution of Ce from other lanthanide elements, such as La, Pr, and Nd, suggesting the lanthanides should be separately investigated. The use of the K-means clustering method on the EELS data of FCCI region revealed different phases, especially Fe-Ce and Zr-C, that concurred with the findings from EDS and STEM-EELS elemental mappings.

Crystallographic Characterization of Gypsum Synthesized from Marine Wastes: Babylonia japonica, Olive sayana, and Conasprella bermudensis

The study synthesized gypsum nanocrystals using conventional wet chemical precipitation methods from marine mollusks like Babylonia Japonica, Olive Sayana, and Conasprella bermudensis. Different characterization techniques like Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDX) were used to confirm the formation of the nanocrystals. XRD data assessed various structural parameters, including the dimension of the unit cell, crystallinity index, specific surface area, lattice parameters, dislocation density, and macrostrain. The Rietveld refinement study did not reveal the formation of alternate phases, and the predicted lattice parameters, Full Width at Half Maximum (FWHM), and X-ray density contradicted the actual data. The synthesized gypsum displays crystallite dimension within the acceptable range of < 200 nm, as calculated using various XRD model equations. Additionally, the values for strain (2× 10-4 to 4 × 10-4), stress (-1×107 to 2×107 N/m2), and energy density (2.87 × 102 to 2.16× 103 J/m3) were also estimated for the synthesized samples. The preferential growth calculation indicates stable phase formation of gypsum along the (020) and (040) plane. Furthermore, The study compared the properties of gypsum, including pH, conductivity, and potential difference (PD), in soil extraction and an aqueous medium.

Optimization of Structural, Dielectric, and Electrical Properties in Lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 through site engineering for Biocompatible Energy Harvesting

Piezoelectric energy harvesting has recently gained attention due to its high power density and potential for self-powered sensor networks. This study investigates the effects of dopants on Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramics, examining Strontium (Sr2+), Zinc (Zn2+), and praseodymium (Pr3+/4+) ions at different sites and their impact on structural, dielectric, and electrical properties. X-ray diffraction and Rietveld analysis reveal a coexistence of tetragonal and rhombohedral/orthorhombic phases, with a predominant tetragonal phase, confirmed by Raman analysis. Energy-dispersive X-ray spectroscopy ensures chemical homogeneity. The density measurements indicate a dense microstructure with a relative density of 90-95%. Dielectric analysis shows a relaxor-like behavior in AB-site doped BCZT ceramics, validated by polarization-electric field hysteresis loops. B-site doped BCZT ceramics exhibit ultra-low leakage currents, approximately 103 times lower than undoped BCZT. An optimized biocompatible flexible film-based energy harvester, incorporating A-site doped BCZT ceramic particles, demonstrated impressive energy harvesting capabilities. A simple finger tapping generated ~80.2V and ~18.2nA, with an average peak-to-peak power density of 7.6 µW-cm-3. These results highlight the significant potential of dopant inclusion in BCZT ceramics, marking a major advancement in doping strategies for piezoelectric energy harvesting in miniature electronics.

Dichloromethane -methanol fraction of Mahonia nepalensis containing Berberine, Jatrorrhizine, and tetrahydroberberine as corrosion inhibitor for mild steel

A potentially superior alternative source of environmentally acceptable corrosion inhibitors for metallic materials is plant extracts. This study reports on the use of compounds separated from Mahonia nepalensis (MN) bark extract as an environmentally friendly corrosion inhibitor for mild steel (MS) in 1 M H2SO4. The organic layer was separated from MN bark extracts and then Berberine, Jatrorrhizine, and Tetrahydroberberine were identified and quantified by Liquid column mass spectroscopy (LC-MS) in dichloromethane (DCM) −Methanol fraction of Mahonia nepalensis. The DCM − Methanol fraction of extract was characterized by Ultra violet − visible spectroscopy (UV–Vis) and Fourier Transform Infrared (FTIR). The DCM-Methanol fractions in 1 M H2SO4 were applied to study corrosion inhibition of MS by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed above 91 % inhibition efficiency (IE) for DCM-Methanol fraction containing 2.12 ppm berberine, jatrorrhizine, and tetrahydroberberine at room temperature indicating that it is an effective and cheap candidate for the corrosion prevention of MS in industry. The potentiodynamic polarization demonstrated a reduction in current density without affecting the reaction mechanism but reduced the hydrogen reduction indicated by suppression in cathodic current. Based on polarization curves and open circuit potential, it exhibited mixed inhibitory behavior. Similarly, EIS analysis revealed a drop in double-layer capacitance accompanied by an increase in charge transfer resistance. EIS and a scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) ascertain the adsorption of inhibitor molecules forming a protective layer on the MS surface.

Synthesis investigation and exploring of new tetraglycidyl bisurea bisphenyl S polyepoxide as an excellent corrosion inhibitory resin for mild steel in 1M HCl environment: Comprehensive approaches

This work reports the synthesis of new epoxy resin namely tetraglycidyl bisurea bisphenyl S (TGBUBS). TGBUBS was characterized through using nuclear magnetic resonance (1H NMR and 13C NMR) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). TGBUBS was investigated as an excellent organic inhibitor for protecting the mild steel from corrosion in 1M HCl solution at different concentrations. Anticorrosion protection behaviors were evaluated and more discussed including different techniques such as potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and contact angle (CA) measurements. The obtained results showed that the TGBUBS exhibited inhibition efficiencies at lower concentration are 93.19 % (PDP) and 91.21 % (EIS), respectively. Further, PDP measurements indicated that the TGBUBS acted as a mixed-type inhibitor in 1M HCl solution. Furthermore, SEM and EDS analysis showed a significant reduction in the corrosion on the mild steel surface when the inhibitory epoxy resin was present compared to the blank solution (1M HCl). The effectiveness and interactions of the new epoxy resin on the mild steel surface were also predicted using DFT calculations and molecular dynamics (MD) simulations. The theoretical approaches are in agreement with the experiment results.

Evaluation of riboflavin, nanocurcumin, and hydrogen peroxide under light conditions: reduction of mature dental biofilms and enamel mineral loss

BackgroundBiofilms are a potential harbor for many microorganisms. The aim of this study was to test the efficacy of riboflavin (Rib), nano-micelle curcumin (NC), and hydrogen peroxide (HP), alone and in combination with the respective light (light-emitting diode (LED) or 980 nm diode laser) on the reduction of Streptococcus mutans and Lactobacillus acidophilus dual-species biofilms and their effect on the enamel mineral loss. Materials and methodsThe biofilms were formed on saliva-coated enamel slabs. Then, the biofilms were treated with antimicrobial photodynamic therapy (PDT) based on LED, Rib, and NC photosensitizers and with HP also based on a 980 nm diode laser (n = 8 per group). A crystal violet assay was performed to determine the reduction of the dual-species biofilms. The enamel slabs were analyzed for calcium and phosphorus content by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). ResultsWhile HP-PDT showed a reduction of 37% (p < 0.001), PDT with NC resulted in an even greater reduction of dual-species biofilms (40%, p < 0.001) than HP- and Rib-mediated PDT. In the EDX test, no significant difference was found between the control group and the treatment groups. ConclusionsThe use of natural photosensitizers such as NC in PDT has an effect that may be potentially important in reducing caries-causing bacteria.

The Effect of Nickel Addition on α-Fe2O3 Synthesis Using NaOH and Application as Lithium-Ion Battery Anode Material

Research has been conducted in the pursuit of developing the performance of batteries. The increasing demand for electronic devices and electric vehicles has driven the development of high-performance lithium-ion batteries (LIBs). Among the various anode materials, α-Fe2O3 has attracted significant attention due to its high theoretical specific capacity of 1007 mAh/g. However, its low conductivity and poor rate capability limit its practical application. To address these issues, this study investigates the addition of nickel (Ni) into α-Fe2O3 through a co-precipitation method. The synthesized materials were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy with Energy-Dispersive X-ray spectroscopy (SEM-EDX). The electrochemical performance was evaluated using an LCR meter and charge-discharge cycling. The results showed the addition of Ni improved the conductivity of the α-Fe2O3 material. The optimal Ni content was found as much as 18×10-4 mol which exhibits the highest conductivity and specific capacity. The synthesized α-Fe1.965Ni0.035O3 material demonstrated a specific charging capacity of 1.8433 mAh/g and a specific discharging capacity of 1.8388 mAh/g. These findings suggest that Ni-doped α-Fe2O3 has the potential to be a promising anode material for high-performance lithium-ion batteries (LIBs).

Specific and high-affinity adsorption of volatile organic compounds on titanium dioxide surface.

The interaction between metal oxides and volatile organic compounds (VOCs) from the ambient atmosphere plays an important role in environmental and catalytic applications. Previous scanning probe microscopy and x-ray spectroscopy studies revealed surprisingly that the TiO2 [rutile (110)] surface selectively adsorbed atmospheric carboxylic acids, which typically exist in only parts-per-billion concentrations. In this work, we used in situ sum-frequency vibrational spectroscopy to study the interaction between rutile (110) and typical VOC molecules, including formic acid, acetic acid, and formaldehyde. Spectra from all three adsorbed molecules on rutile (110) were similar to the rutile surface spectrum in the ambient atmosphere, showing a broad resonance near 2950cm-1 that can be attributed to the bridging bidentate adsorption of corresponding compounds. In contrast, on a fused silica surface, a molecular monodentate adsorption configuration was observed for all the molecules, with aliphatic carbons appearing to be the dominant adventitious species.

Synthesis and characterization of gelzan nanocomposite scaffold incorporating Ag/Fe2+ co-doped hydroxyapatite for antibacterial bone tissue regeneration

Abstract A nanocomposite scaffold was developed using gelzan, a natural extracellular polysaccharide, as the biopolymer matrix. Gelzan (GZ) was combined with Ag/Fe2⁺ co-doped hydroxyapatite (HAp) particles to enhance the scaffold’s biological properties. The aim of incorporating Ag/Fe2⁺ co-doped HAp was to utilize the combined antibacterial and bioactive properties of these components. The synthesized Ag/Fe2⁺ co-doped HAp nanoparticles, along with the gelzan-based nanocomposite scaffold produced via freeze-drying, underwent comprehensive analyses. These included Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and biological assessments for antibacterial activity and bioactivity. The results demonstrated that the Ag/Fe2⁺ co-doped HAp nanocomposite scaffold possessed favourable physicochemical properties. Furthermore, the integration of Ag and Fe2⁺ co-doped HAp into the gelzan matrix was confirmed, revealing the scaffold’s structural and compositional characteristics. Tests of apatite formation in simulated body fluid (SBF) indicated the development of layered apatite precipitates after 7 days. The scaffold also exhibited significant antibacterial activity, with inhibition zones of 7.35 ± 0.70 mm and 5.54 ± 0.60 mm against Staphylococcus aureus and Escherichia coli, respectively. These findings suggest the scaffold’s promising potential as a biomaterial for bone tissue regeneration.

Pulsed N2 plasma surface treatment for AlGaN/GaN HEMTs prior to PECVD SiNx passivation to reduce plasma damage

In this work, a pulse-mode N2 plasma surface treatment process was proposed as a means of reducing plasma damage and improving the GaN/GaOx ratio on the surface before SiNx deposition, which further contributes to an enhanced density of 2DEG and a reduced sheet resistance. With the pulsed N2 plasma surface treatment combined with subsequent SiNx passivation, the fabricated GaN HEMTs exhibit negligible current collapse and suppressed leakage current. The improved behavior is attributed to the fact that the pulsed N2 plasma is capable of nitriding the surface and removing carbon contaminants as identified through x-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy. Compared to the traditional continuous-wave-mode N2 plasma, the pulsed N2 plasma pre-treatment effectively prevents continuous collisions of the plasma during acceleration, thereby significantly reducing plasma damage. This work offers valuable insights for surface treatment processes in micro- and nanofabrication.

Material analysis on semi-permanent makeup needles.

The cosmetic-tattoo industry is evolving every year and the microstructures of the equipment have the great potential for semi-permanent makeup applications. Present paper explores the materials and microparticles of semi-permanent makeup tattoo needles. The surface of the five-round-shader tattoo needle used in semi-permanent makeup process was examined by scanning electron microscopy, and its elemental composition was analyzed by energy-dispersive X-ray spectroscopy. The comparison of five-round-shader needles have undergone thorough observation: original five-round-shader needle and distorted five-round-shader needle. The diameter of the sharp and rounded needle tip was measured at approximately 6.80μm, while the deformed needle tip was approximately 16μm thick, about 2.5 times thicker than the rounded needle tip. Many rosette-shaped lead (Pb) particles and irregular clusters adhere to the welded areas and closely adjacent needle shaft surfaces. The lead particles have a diameter ranging from 4μm to 5μm and exhibit a grid-like structure with a consistent thickness of plate-like shape. The distorted structure of Pb in rosette-shaped formations is shown to have originated from the grinding and polishing processes during needle manufacturing. To produce sterilized tattoo needles, high-quality tattoo needle inspection processes are necessary to remove any unhygienic substances adhering to the needle surface.