Fourier-transform infrared nanospectroscopy (nano-FTIR), a technique based on scattering-type scanning near-field optical microscopy (s-SNOM), enables the characterization of materials’ vibrational properties with nanometric spatial resolution. This capability arises from highly confined broadband infrared radiation near the curvature apex of a metallic tip, allowing the detection of amplitude and phase signals associated with the local tip–sample interaction. Consequently, the physical interpretation of s-SNOM and nano-FTIR signals critically relies on understanding the tip–sample interaction. Theoretical models, such as the Finite Dipole Model (FDM), have provided valuable insights into this interaction, offering analytical formulations for the near-field amplitude response. However, the phase signal, often associated with infrared absorptive contributions in weak oscillator regimes, remains less direct from a theoretical standpoint. To address this issue, we explore a method based on the Kramers–Kronig relations (KKR) within the FDM framework, yielding analytical approximations for normalized amplitude–phase relations that agree well with simulated data under the assumptions considered. Furthermore, the proposed method is consistent with the causality requirements imposed by the KKR. This relation allows the reconstruction of the normalized phase from normalized amplitude data within the FDM approximation, providing an additional physical interpretation in terms of complex polarizability. To evaluate the FDM–KKR framework, we reconstructed the normalized phase and normalized amplitude of the effective polarizability of the PMMA polymer in simulated spectra. Our findings indicate that the proposed FDM–KKR framework offers a complementary, self-consistent analytical approach for interpreting normalized near-field optical signals in terms of measurable quantities, thereby bridging analytical modeling and experimental observations.

Synthesis route, rather than Ni : V ratio, controls micropore capacitance in alpaca manure-derived AC/VNiO composites, yielding durable supercapacitor electrodes with >99% capacitance retention after 50 000 cycles.

The placement of dental implants for aesthetic and functional rehabilitation is increasingly common, yet challenges remain in understanding the cellular response of bone tissue to biomaterials post-implantation. This study investigates the deposition of hierarchical surface coatings using bioactive glass and hydroxyapatite nanoparticles produced by pulsed laser ablation, aiming to enhance the bioactivity and biocompatibility of dental implants. The hierarchical coatings, composed of micro and nanoscale structures, were evaluated for their morphology, chemical structure, and cellular responses through in vitro assays. The results demonstrated that nanoparticles produced from hydroxyapatite (NPHA) exhibited sizes ranging from 38 to 220 nm, while those from niobo-phosphate bioglass (NPBg) ranged from 18 to 164 nm. These particles formed heterogeneous coatings with increased hydrophilicity, as evidenced by contact angle measurements showing values of 42 degrees for NPHA and 8 degrees for NPBg, compared to 72 degrees and 91 degrees for uncoated silicon and titanium, respectively. Cellular adhesion tests revealed that NPHA and NPBg coatings significantly improved cell adhesion and spreading after 24 h, with NPBg showing the highest total area occupied by cells. Furthermore, mineralization assays indicated that both coatings enhanced calcium phosphate precipitation, with significant differences observed compared to control samples after 7 and 21 days. These findings suggest that hierarchical coatings with tailored micro and nanoscale features can substantially improve the osseointegration and bioactivity of dental implants, offering a promising approach for advanced biomaterials in regenerative medicine.

This study introduces a hybrid numerical-analytical methodology for interpreting, for the first time, both the amplitude and phase of Synchrotron Infrared Nanospectroscopy (SINS) spectra of hydroxyapatite (HA) thin films. The approach combines the Self-Referenced Interferometry Model (SRIM) with the Kramers-Kronig relations (KKR). HA films with thicknesses of 100 nm and 600 nm were fabricated via magnetron sputtering and characterized using Fourier-transform infrared (FTIR) spectroscopy to identify vibrational modes of the phosphate group. These frequencies were used as initial parameters for Lorentzian-based SRIM fitting of the SINS amplitude spectrum. Both the integral and differential forms of KKR were applied to the fitted amplitude spectrum to reconstruct the phase, which was subsequently validated against experimental SINS data. The differential form further enabled analytical decomposition of the phase into individual oscillator and non-resonant contributions, revealing features not evident in the amplitude alone. The strong agreement between experimental and modeled spectra demonstrates the reliability of FTIR-guided SRIM fitting combined with KKR analysis. This methodology effectively bridges far-field and near-field infrared spectroscopy, showing that HA spectral responses comply with causality and analyticity. Moreover, it supports accurate phase reconstruction even under low-intensity signal conditions, indicating broad applicability to other nanostructured materials. Altogether, this work establishes a robust framework for interpreting SINS spectra and advances phase-resolved diagnostics and hybrid modeling strategies for nanoscale vibrational analysis.

This study combines experimental and density functional theory (DFT) to evaluate the influence of alkaline cation characteristics on the electronic structure and photodegradation efficacy of organic dyes in MNbO3 (M = Na, K) perovskites. The X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Near Edge Spectroscopy (XANES) spectra at the Nb edge of the Perovskites were employed to characterize its chemical and structural properties. The DFT calculations were carried out to simulate XANES spectra as well as the structural and electrical properties of KNbO3 and NaNbO3. Our results show that the simulated and experimental XANES spectra are similar, indicating that the computational simulations were able to capture the local structure of the niobate samples. In addition, a photocatalytic experiment was conducted to benchmark the methylene blue consumption efficiency between different niobates. The findings demonstrated that KNbO3 is more efficient than NaNbO3 for methylene blue UV photocatalytic degradation, which is associated with their electronic properties. This arises as a direct result of the variably deformed NbO6 octahedra resulting from the different alkali used. Our findings facilitate the advancement of stable and abundantly available photocatalysts, which may be employed for energy-intensive processes such as the mineralization of organic water pollutants and hydrogen production by water splitting.

Earth-abundant antimony selenide (Sb2Se3) is a promising material for the thin-film photovoltaic applications due to its desirable optoelectronic properties and suitable band gap. In this work, we present a comprehensive study on the structural and surface properties of Sb2Se3 thin-films for the potential applications in solar cells. The Sb2Se3 samples were grown on Si (100) substrate and at different substrate temperatures using radio frequency (RF) magnetron sputtering. The XRD diffractogram exhibits that Sb2Se3 is the predominant phase in all the samples, whereas the TEM measurements confirm the nanocrystalline nature of the samples. Raman spectroscopy measurements in the range of 30-500 cm(-1) displays the Raman shifts at 148, 190 and 206 cm(-1), which confirms the presence of the Sb2Se3 phase. The average surface roughness and grain size were obtained via surface topography with the help of the high-resolution AFM images. The EDS spectra revealed the presence of both Se and Sb as constituent elements in all the samples. The deconvolution of XPS spectra of Se 3p and Sb 3d core level disclose the Sb+3 and Se-2 oxidation state and further confirms the presence of Sb2Se3 phase. The XPS and EDS measurements predict that there is loss of Se during the deposition and it could have adverse effects on the performance of Sb2Se3 solar cell devices.

Este artigo tem por objetivo abordar a construção de uma instrumentação para a mitigação do acúmulo de poeira estática na superfície de espelhos de detectores industriais usados no controle de qualidade da fabricação de tubos FIOLAX® clear instalados nas linhas de produção em ambiente de indústria vidreira. A produção de tubos de vidro conta com diversos equipamentos para garantir a qualidade de produção e as especificações do produto. Dentre esses equipamentos estão os detectores de defeitos que possuem espelhos que refletem a superfície do tubo de vidro para os sensores que posteriormente serão transformados em imagens e sinais a serem analisados por um software especialmente desenvolvido para essa finalidade. O acúmulo de poeira estática na superfície do espelho afeta diretamente a detecção pois interfere no sinal enviado às câmeras dos detectores, acarretando na parada da linha de produção devido a necessidade de manutenção no equipamento para limpeza ou troca dos espelhos, gerando uma perda de até quinze horas mensais de produção. O método utilizado aborda uma combinação de vidro recoberto por filme fino de FTO e jato de ar ionizado, mudando a energia elétrica estática de superfície para mitigar o acúmulo de poeira e a ação mecânica do sopro de ar para afastá-las da área de interesse. O tratamento com ar ionizado apresentou o melhor resultado, foram encontrados sete vezes menos concentração de grãos de poeira em comparação com apenas o fluxo de ar não-ionizado e quinze vezes menor se comparado com as amostras do grupo controle (sem nenhum tratamento).

A novel catalyst, a nanostructured cubic -WC (c -WC) flat film, is introduced for the hydrogen evolution reaction (HER) using a specialized magnetron sputtering system. This method results in over 94% crystalline c-WC0.95 formation at room temperature, featuring high -density stacking faults and twin defects. The catalytic performance of the c -WC film for HER is investigated through theoretical simulations and experimental studies. Density -functional theory (DFT) suggests that the c -WC (100) surface exhibits faster reaction kinetics than c -WC (111) surface, approaching the efficiency of Pt (111) surfaces. Experimentally, the c-WC0.95 film exhibits a high electrochemical surface area and increased active sites due to surface defects. Differential electrochemical mass spectrometry (DEMS) confirms an onset potential for HER of -50.0 mV for c-WC0.95 films and establishes electrodesorption as the rate -determining step. Overall, the c -WC film emerges as a cost-effective and efficient catalyst for green hydrogen production, showcasing excellent reproducibility and electrochemical stability.

X-ray photoelectron spectroscopy (XPS) is one of the main tools for hydroxyapatite (HA) surface characterization in developing materials for biomedical and heterogeneous catalysis. Despite the XPS technique's potential to correlate binding energies with existing photo-emitter sites on near-surfaces, few previous studies analyzed this aspect for HA and metal-substituted HA surfaces. In this work, we theoretically reconstructed the XPS spectra of stoichiometric HA and lead-substituted hydroxyapatite (PbCaHA, Ca10-xPbx(PO4)6(OH)2; x = 2, 10) using a firstprinciples linear combination of atomic orbitals embedded cluster approach and periodic supercell band structures within the framework of Density Functional Theory (DFT). We take into account photoemission lines contributions from Ca(1), Ca(2), Pb(1) and Pb(2) sites located on surface and near-surface depths (up to -15 angstrom) along the (001) and (100) surfaces. The calculated DFT spectra of HA and PbCaHA were compared with highresolution XPS spectra previously characterized by synchrotron X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), high-resolution transmission electron microscopy (HRTEM) and electron energyloss spectroscopy (EELS). A combined theoretical and experimental approach enables decoding of the complex structure of HA and PbCaHA in XPS spectra. It was found that XPS binding energies profiles depend significantly on photo-emitters from near-surface sites and surface crystallographic orientation. The main Ca 2p3/2 envelope peak in HA is predominantly from Ca(1) and Ca(2) sites (-347.4 eV), while the weaker peak is due to the Ca(2) site only (-345.0 eV). Variations on HA nanoparticle morphology could be a critical factor for changes in XPS binding energies' profile.

Background: Bioceramic nanometer coatings have been regarded as potential substitutes for plasma-sprayed hydroxyapatite coatings, and the association with bone morphogenetic protein (BMP) is an attempt to achieve faster osseointegration to hasten oral rehabilitation. Objective: This study aimed to investigate the effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) on the osseointegration of titanium implants coated with a thin film surface of hydroxyapatite (HA). Methods: Two implants (n = 24) were placed in each white New Zealand rabbits’ femur (n = 6). Implants were placed in the right femur after standard instrumentation (A and B) and in the left femur after an over-instrumentation (C and D), preventing bone-implant contact. The distal implants were installed associated with rhBMP-7 (groups B [regular instrumentation] and D [over-instrumentation]) and, also, in the absence of without BMP (control groups A [regular instrumentation] and C [over-instrumentation]). After 4 weeks, the animals were euthanized. The bone blocks containing the implants were embedded in methyl methacrylate and sectioned parallel to the long axis of the implant, which were analyzed by image segmentation. The data were analyzed using a nonparametric statistical method. Results: We observed that Group A had a mean bone formation of 35.6% compared to Group B, which had 48.6% (p > 0.05). Moreover, this group showed 28.3% of connective tissue compared to Group A, with 39.3%. In the over-instrumented groups, rhBMP-7 (Group D) showed an enhanced and significant increase in bone formation when compared with the group without rhBMP-7 (Group C). Conclusion: We concluded that the association of rhBMP-7 to thin nanostructure HA-coated implants promoted greater new bone area than the same implants in the absence of rhBMP-7, mainly in cases of over-instrumented implant sites.

A Plastic Optical Fiber (POF) in U-shape, functionalized with a thin film of copper oxide, was developed as a hydrogen sulfide gas sensor. Unlike resistive-type Semiconductor Metal Oxide (SMOX) gas sensors, the present optical sensing probe is neither electrically charged nor demands a heating system as it functions at room temperature (25 degrees C). Pulsed Laser Deposition (PLD) method was used to coat optical fibers with copper, nickel and tin oxides. However, only CuO-functionalized fibers demonstrated a detectable signal to the H2S exposure. The PLD copper oxide thin films were composed of a dominantly amorphous structure and embedded Cu2-xO crystallites. Fourier Transform Infrared Spectroscopy (FTIR) demonstrated that the PLD process created negatively charged oxygen species adsorbed on the surface of the Cu2-xO, which react with H2S are responsible for the sensing mechanism. A state-of-the-art modification in the fiber's geometry, with more curves, was presented and improved the Signal to Noise Ratio (SNR). The sensor demonstrated a response time as low as 1 min during an exposure to 200 ppm H2S and a minimum detectable H2S concentration, CH2S, around 10 ppm. The experimental data led to an interpolation that estimates a logarithmic relationship between the saturated signal and CH2S. The sensor demonstrates a remarkable selectivity to H2S. Furthermore, the saturated signal represents an inverse relation with the Relative Humidity (RH).

We report the synthesis of Pr0.5Sr0.5MnO3 nanoparticles (NPs) by pulsed laser deposition (PLD) with varying energy per pulse (100, 200 and 300 mJ) under Ar (Argon) atmosphere. We have obtained NPs with average diameters of 10, 16, 19 nm, with narrow size distribution and core-shell morphology, in which the cores are crystalline and the shells amorphous. Due to the large amount of amorphous phase, heat treatment at temperatures of 750 and 900 degrees C was applied and X-ray diffraction with Rietveld refinement analyses indicated that highly crystalline PSMO NPs were obtained with an average diameter of 35 nm and 65 nm, respectively. Note that the annealing was also useful to tune the NPs size. Target magnetic investigation indicated that the Pr3+ and Mn3+/Mn4+ magnetic sublattices couple in an antiferromagnetic (AFM) fashion at low temperatures, undergoing a reversible transition to the ferromagnetic (FM) state around 200 K. However, heat-treated NPs behave differently - the ZFC and FC curves exhibit an irreversibility that is most likely associated with the weakening of AFM interactions on the surface of the NPs. Despite this characteristic, the NPs exhibit a sharp magnetic transition (FM-PM) with T-C around 300 K, which makes these NPs useful candidates for magnetocaloric, magnetoresistivity and medicine applications.

The development of procedures for the synthesis of p-type NiO on top of non-degenerate semiconductors is of great interest due to the potential applications in several areas of microelectronics. In this work, p-type NiO films with different resistivity values are obtained by heating at different temperatures Ni(OH)2 layers electrodeposited on n-type monocrystalline Si substrates. Characterizations by X-ray diffraction and X-ray photoelectron spectroscopy have evidenced the phase change, from hexagonal β-Ni(OH)2 to cubic NiO for all treated samples, with improved crystallinity for higher heating temperatures. The effect of the electrochemical parameters and heat treatment temperatures on the thickness and surface morphology of the films was also analyzed by mechanical profilometry and scanning electron microscopy, respectively. The p-type behavior of the films and the electrical resistivity values were determined from electrical measurements using a two-point probe system in a sandwich configuration. Higher resistivity values were found for films subjected to higher heat treatment temperatures.

The adaptation of trabecular bone microstructure to mechanical loads has been intensively investigated. However, loading-unrelated aspects of trabecular architecture remain unclear. We used synchrotron radiation-based X-ray microtomography to study the 3D microarchitecture of newly formed trabecular tissue in a defect produced in the cortical region of the rat tibia diaphysis, in the absence (7, 14, and 21 days) or the presence (21 days) of carbonated hydroxyapatite/alginate (cHA) microspheres. This work provides the first evidence that the woven bone trabecular network, formed during the healing process, displays a well-organized 3D microarchitecture consisting of nodes with 3 (3-N), 4 (4-N) and 5 (5-N) connecting trabeculae, with a mean relative abundance of (3-N)/(4-N)/(5-N) = 66/24/7, for the analyzed periods. The measured inter-trabecular angles (ITA) distribution presented a Gaussian profile, with mean value at 115 degrees for 3-N nodes, and 105 degrees for 4-N nodes, close to the angles of idealized 3D regular structures (120 degrees and 109.5 degrees, respectively). Changes in the dispersion of ITA distribution suggested that a highly symmetric trabecular fabric organized under tensegrity principles is formed early during the bone healing process. Post-implantation, cHA disaggregated into multiple fragments (similar to 20-400 mu m), stimulating osteoconduction and bone growth toward the interior of the medullary cavity. The presence of biomaterials in bone defects affected the trabecular dimensions; however, it did not interfere with the formation of geometrical motifs with topological parameters similar to those found in the sham-defects. Statement of Significance The trabecular bone microstructure enables the tissue to meet the necessary mechanical and functional demands. However, the process of trabecular microarchitecture formation during healing, in the absence or presence of a bone graft, is not yet well understood. This work demonstrated that, from the beginning of its formation in cortical bone defects, the woven-bone trabecular network is spatially organized according to the principle of tensegrity. This microarchitecture is comprised of highly symmetric geometric motifs and is an intrinsic characteristic of trabecular growth, regardless of hierarchical scale or mechanical stimulation. The addition of a biodegradable nanostructured calcium phosphate graft did not disrupt trabecular microarchitecture; however, graft biodegradation should be controlled to optimize the reproduction of intrinsic trabecular motifs throughout the defect. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd.

Statement of problemNonthermal argon plasma (NTAP) has been reported to improve the bond strength of resin cements to yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics. However, the effect of the inevitable delay before cementation and after treating Y-TZP ceramics with NTAP is unclear.PurposeThe purpose of this in vitro study was to investigate whether delays of 8, 12, and 24 hours between the Y-TZP ceramic treatment with NTAP and the cementation would affect the surface energy and the bond strength of a self-adhesive resin cement to Y-TZP ceramic.Material and methodsSixty plates and 50 blocks of 3Y-TZP ceramic were divided into 2 groups (n=30 and n=25): as-sintered (AS) and airborne-particle abraded with 50-μm Al2O3 (APA). These groups were further divided into 5 subgroups (n=6 and n=5) according to the delay between the NTAP treatment and the measurement of surface energy and microtensile bond strength (μTBS) evaluation: (0, 8, 12, and 24 hours). For both 3Y-TZP surface conditions (AS and APA), a control group without NTAP treatment was used (ASC and APAC). The surface energy (SE) was evaluated with a goniometer and the 3Y-TZP elemental composition with X-ray photoelectron spectroscopy (XPS). For the μTBS test, the 3Y-TZP ceramic blocks were cemented to composite resin blocks with a self-adhesive resin cement. After storage in distilled water at 37 °C for 24 hours, the 3Y-TZP-composite resin blocks were sectioned into beams and submitted to a μTBS test. Data were submitted to 2-way ANOVA and the Tukey HSD test (α=.05).ResultsFor the AS group, NTAP increased the SE irrespective of the delay before measurement: ASC<0 hour=8 hours=12 hours=24 hours (P<.05). For the APA group, except after 12 hours, NTAP also increased the surface energy (P<.05). XPS analysis showed an increase in the oxygen/carbon ratio after NTAP treatment for both groups. For the AS group, NTAP increased the μTBS after 0, 8, and 12 hours (P<.05), whereas for the APA group this occurred only after 8 hours (P<.05). For the AS and APA groups, the highest μTBS was reached after 8 hours (P<.05).ConclusionsTreatment of 3Y-TZP ceramic with NTAP improved the SE and increased the μTBS of self-adhesive resin cement to 3Y-TZP ceramic. These effects were time dependent, with better results at 8 hours after NTAP treatment.

The calcium‑phosphorus ratio (Ca/P) has an important role in calcium phosphate applications, as a slight change in this ratio results in substantial modifications of their characteristics. Hydroxyapatite is a bioactive ceramic of the calcium phosphate family, and its composition and crystalline structure are similar to the human bone. For this reason, it is widely used to promote bone integration in prosthetics and scaffolds. Prosthetics are usually made of metal and coated with bioceramics and the some techniques used to make these coatings depositions conserve the stoichiometry from the target during deposition. Therefore, studying the target Ca/P is a way to guaranteeing the final deposition stoichiometry. In this study, we investigated the One Point Calibration – Laser Induced Breakdown Spectroscopy (OPC-LIBS) method for the measurement of the Ca/P of hydroxyapatite targets. This method is quantitative, based on the determination of correction parameters via analysis of a standard sample with known stoichiometry. Results were compared to well-established techniques of X-ray Fluorescence (XRF) and Atomic Absorption Spectroscopy (AAS) and showed that the deviation in the difference is less than 5%, proposing a substitute for elemental analysis. Moreover, this method has technical advantages such as rapid measurements, no need for sample preparation or destruction and easy automation.

In this study, we investigated aspects about the nanostructure of calcium phosphate films formed by pulsed laser deposition under a high-pressure gas (argon) environment (1 Torr) that are not addressed in the literature by using infrared and green laser sources. The plume generated from an ablated hydroxyapatite target was deposited directly over transmission electron microscopy (TEM) grids during 120 s to allow for the use of TEM techniques to investigate the morphology, composition and structure of deposited films from the micron to the nanoscale. The films were found to comprise five different calcium phosphate structures: (1) unstructured amorphous thin film formed by the deposition of ions and molecules over the substrate, (2) dense nanoparticles (<20 nm) formed over the substrate, (3) low Ca/P ratio spherical particles (<400 nm) formed on the way to the substrate, (4) rich Ca/P ratio ring-shaped particles (>400 nm) ejected from the target and (5) crystalline particles (similar to 500 nm) removed from the target. Although all samples presented these five structures, the morphology, abundance and size population were all different. This work opens a window to elucidate the complex mechanism underlying calcium phosphate film deposition and growth by pulsed laser deposition.

In this work, there were analyzed dental remains of a Toxodon sp. (Mammalia, Notoungulata) specimen rescued from the riverbank of the Ypané River in Paraguay. Several techniques were used to analyze the different geological aspects of the samples, thus providing keys to the understanding of fossilization processes and the implications of paleoenvironmental conditions in the apatites present in the dental remains. The identification of the chemical substances present in the sample was made by Raman and Fourier Transform Infrared (FTIR) spectroscopy, the chemical composition of the samples was determined using energy dispersive X-ray fluorescence (EDXRF) and X-ray photoelectron spectroscopy (XPS), and the mineralogy by X-ray Diffraction (XRD). It is worth mentioning that this work is the first in the area of Paleometry carried out in Paraguay.