Enhancing ozone catalytic decomposition through acid treatment of α-MnO2 for improved activity and humidity resistance.

Post-etching method using dilute acid solutions is an effective technology to modulate the surface compositions of metal-oxide catalysts. Here the α-MnO2 catalyst treated with 0.1 mol/L nitric acid exhibits higher ozone decomposition activity at high relative humidity than the counterpart treated with acetic acid. Besides the increases in surface area and lattice dislocation, the improved activity can be due to relatively higher Mn valence on the surface and newly-formed Brønsted acid sites adjacent to oxygen vacancies. The remnant nitro species deposited on the catalyst by nitric acid treatment is ideal hydrophobic groups at ambient conditions. The decomposition route is also proposed based on the DRIFTS and DFT calculations: ozone is facile to adsorb on the oxygen vacancy, and the protonic H of Brønsted acid sites bonds to the terminal oxygen of ozone to accelerate its cleavage to O2, reducing the reaction energy barrier of O2 desorption.

Enamel Deproteinization or Sandblasting for Enamel Reconditioning Before Acid Etching to Enhance the Shear Bond Strength of Metallic Brackets in a Third Bonding: An In Vitro Study.

BACKGROUND: Enamel conditioning with 37% phosphoric acid is the most common technique during orthodontic bracket bonding procedures. However, due to the repeated de-bonding of the orthodontic brackets during treatment, other methods were needed to condition the enamel surface and increase the bond strength. This study aimed to compare the effect of conditioning the enamel surface by sandblasting with aluminum oxide particles or 5.25% sodium hypochlorite gel in combination with acid etching compared to acid etching alone on shear bond strength (SBS). MATERIAL AND METHODS: One hundred eight extracted upper premolars were randomly divided into three groups according to the conditioning enamel surface method. After the first and second bonding of metal brackets, new metal brackets were bonded with a total-etching adhesive after enamel conditioning using different methods: acid etching only (37% phosphoric acid for 30 seconds) (AE group), sodium hypochlorite associated with acid etching (5.25% NaOCl gel for 60 seconds and then acid etching for 30 seconds) (NaOCl-AE group), and sandblasting associated with acid etching (sandblasting for five seconds and then acid etching for 30 seconds) (SB-AE group). The shear bond strengths of the brackets were tested with a universal testing machine. One-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) tests were used to detect significant differences in shear bond strength among groups at the third bonding. Repeated-measure ANOVA and Bonferroni's tests were used to detect significant differences in shear bond strength among the bonding attempts within each group. RESULTS: 5.25% sodium hypochlorite associated with the acid etching method produced significantly greater shear bond strength than sandblasting associated with acid etching and acid etching only methods at the third bonding (16.40 ± 5.80 MPa, 13.60.47 ± 6.40 MPa, and 9.90 ± 4.40 MPa, respectively; P < 0.001). However, there was no significant difference between the AE and SB-AE groups (P = 0.247). In addition, we found a significant decrease in the shear bond strength within each group after each bonding attempt. CONCLUSION: Conditioning the enamel surface with 5.25% sodium hypochlorite associated with acid etching produced greater bond strength than conditioning by sandblasting associated with acid etching and acid etching only at the third bonding. The bond strength of the metal bracket decreased with increasing bonding attempts, even with the application of enamel surface conditioning methods.

Synthesis of Hydrofluoric (HF) Acid Free, Two-Dimensional (2D) Tantalum Carbide MXene Nanosheets and Quantum Dots.

MXenes are two-dimensional (2D) transition metal-based carbides, nitrides, and carbonitrides that are synthesized from its precursor MAX phase. The selective etching of the "A" from the MAX phase yields multi-functional MXenes that hold promise in a wide range of energy-based applications and biomedical applications. Based on its intended application, MXenes are prepared as multilayered sheets, monolayer flakes, and quantum dots. Conventionally, MXenes are prepared using hydrofluoric (HF) acid etching; however, the use of HF impedes its effective use in biomedical applications. This calls for the use of nontoxic HF-free synthesis protocols to prepare MXenes safe for biological use. Therefore, we have discussed a facile process to synthesize biocompatible, HF-free MXene nanosheets and quantum dots.

Highly selective localized surface plasmon resonance sensor for selenium diagnosis in selenium-rich soybeans.

It is a challenge to determine selenium in acid aqueous for environmental monitoring and selenium-rich agricultural diagnosis. Herein, we developed a novel localized surface plasmon resonance (LSPR) sensor to detect Se(IV) ions based on the extraordinary laterals etching of gold nanorods (AuNRs). The etching started from the laterals in the low amount of Se(IV) ions, and accompanied by an apparent red shift of the longitudinal plasmon band (LPB), and then transformed to the tips etching with the upward of Se(IV) ions, the LPB band immediately shifted to the shorter wavelength. The red shift change (Δλ) of LPB band was utilized to quantitative analysis instead of blue shift or absorbance intensity, which gave a high selectivity for the proposed sensor. More importantly, this sensor could be performed in 0.1 mol/L of HCl solution, which achieved the seamlessly jointing with the pretreatment of complex samples, without time-consuming pH adjustment.Successful selenium detection was demonstrated in complex soybean samples that collected from the maturity after spraying organic chelated selenium at full flower period. The sensor provided a promising way to monitor and diagnose selenium in complex environmental samples and selenium-rich crops.

Suppression of Secondary Electron Emission by Vertical Graphene Coating on Ni Microcavity Substrate.

Suppression of secondary electron emission (SEE) from metal surfaces is crucial for enhancing the performance of particle accelerators, spacecraft, and vacuum electronic devices. Earlier research has demonstrated that either etching the metal surface to create undulating structures or coating it with materials having low secondary electron yield (SEY) can markedly decrease SEE. However, the effectiveness of growing vertical graphene (VG) on laser-etched metal surfaces in suppressing SEE remains uncertain. This study examined the collective impact of these methods by applying nanoscale arrays of VG coating using plasma-enhanced chemical vapor deposition on Ni substrates, along with the formation of micrometer-sized microcavity array through laser etching. Comparative tests conducted revealed that the SEY of the samples subjected to VG coating on a microcavity array was lower compared to samples with either only a microcavity array or VG coating alone. Additionally, the crystallinity of VG grown on substrates of varying shapes exhibited variations. This study presents a new method for investigating the suppression of SEE on metal surfaces, contributing to the existing body of knowledge in this field.

Anchoring Metal-Nitrogen Sites on Porous Carbon Polyhedra with Highly Accessible Multichannels for Efficient Oxygen Reduction.

Transition metal-nitrogen-carbon complexes, featuring single metal atoms embedded in a nitrogen-doped carbon matrix, emerge as promising alternatives to traditional platinum-based catalysts, offering cost-effectiveness, abundance, and enhanced catalytic performance. This work introduces a novel method for the etching and doping of zeolitic imidazolate frameworks (ZIFs) with transition metals, creating a uniform distribution of secondary metal centers on ZIF surfaces. By disrupting the crystalline symmetry of ZIFs through synthetic defect engineering, we gain access to their entire internal volume, creating multichannel pathways. The absorption of metal ions is theoretically simulated, demonstrating their thermodynamically spontaneous nature. The selective removal of defect channels under Lewis acidic conditions, induced by metal ion alcoholysis/hydrolysis, facilitates the introduction of metal atoms into ZIF cavities. The resulting single-atom catalyst, after pyrolysis, features a three-dimensional (3D) multichannel structure, high surface area, and uniformly dispersed metal atoms within the N-doped carbon matrix, establishing it as an exceptional catalyst for the oxygen reduction reaction (ORR). Our findings highlight the potential of using metal etching in defect-engineered metal-organic frameworks (MOFs) for single-atom catalyst preparation, paving the way for the next generation of high-performance, cost-effective ORR catalysts in sustainable energy systems.

Probing the interaction range of electron beam-induced etching in STEM by a non-contact electron beam.

Beside its main purpose as a high-end tool in material analysis reaching the atomic scale for structure, chemical and electronic properties, aberration-corrected scanning transmission electron microscopy (STEM) is increasingly used as a tool to manipulate materials down to that very same scale. In order to obtain exact and reproducible results, it is essential to consider the interaction processes and interaction ranges between the electron beam and the involved materials. Here, we show in situ that electron beam-induced etching in a low-pressure oxygen atmosphere can extend up to a distance of several nm away from the Ångström-size electron beam, usually used for probing the sample. This relatively long-range interaction is related to beam tails and inelastic scattering involved in the etching process. To suppress the influence of surface diffusion, we measure the etching effect indirectly on isolated nm-sized holes in a 2 nm thin amorphous carbon foil that is commonly used as sample support in STEM. During our experiments, the electron beam is placed inside the nanoholes so that most electrons cannot directly participate in the etching process. We characterize the etching process from measuring etching rates at multiple nanoholes with different distances between the hole edge and the electron beam.

Atomic Precision Processing of Two-Dimensional Materials for Next-Generation Microelectronics.

The growth of the information era economy is driving the pursuit of advanced materials for microelectronics, spurred by exploration into "Beyond CMOS" and "More than Moore" paradigms. Atomically thin 2D materials, such as transition metal dichalcogenides (TMDCs), show great potential for next-generation microelectronics due to their properties and defect engineering capabilities. This perspective delves into atomic precision processing (APP) techniques like atomic layer deposition (ALD), epitaxy, atomic layer etching (ALE), and atomic precision advanced manufacturing (APAM) for the fabrication and modification of 2D materials, essential for future semiconductor devices. Additive APP methods like ALD and epitaxy provide precise control over composition, crystallinity, and thickness at the atomic scale, facilitating high-performance device integration. Subtractive APP techniques, such as ALE, focus on atomic-scale etching control for 2D material functionality and manufacturing. In APAM, modification techniques aim at atomic-scale defect control, offering tailored device functions and improved performance. Achieving optimal performance and energy efficiency in 2D material-based microelectronics requires a comprehensive approach encompassing fundamental understanding, process modeling, and high-throughput metrology. The outlook for APP in 2D materials is promising, with ongoing developments poised to impact manufacturing and fundamental materials science. Integration with advanced metrology and codesign frameworks will accelerate the realization of next-generation microelectronics enabled by 2D materials.

Stability of the Dentin-Bonded Interface Using Self-Etching Adhesive Containing Diacrylamide after Bacterial Challenge.

Purpose/Aim: Acrylamides are hydrolytically stable at pH lower than 2, and were shown to preserve bonded interface integrity with two-step, total etch adhesives. The objective of this study was to leverage those two characteristics in self-etching primers containing the acidic monomer 10-MDP and test the microtensile bond strength before and after incubation with S. mutans incubation. Materials and Methods: Acidic primers (10 wt % 10-methacryloyloxydecyl dihydrogen phosphate─10-MDP; 45 wt % N,N-diethyl-1,3-bis(acrylamido)propane─DEBAAP, or 2-hydroxyethyl methacrylate─HEMA; 45 wt %, glycerol-dimethacrylate─GDMA) and adhesives (DEBAAP or HEMA/10-MDP/UDMA 45/10/45 wt %) were made polymerizable by the addition of 0.2 wt % camphorquinone, 0.8 wt % ethyl-4-dimethylaminobenzoate, 0.4 wt % diphenyliodonium hexafluorophosphate, and 0.1 wt % butylhydroxytoluene. Nonsolvated materials were characterized for flexural strength (FS), modulus (E), toughness, water sorption/solubility (WS/SL), contact angle, and vinyl conversion (DC). Viscosity was evaluated after adding 20 and 40 vol % ethanol to the primer and adhesive, respectively. The experimental materials or Clearfil SE Bond (CC─commercial control) were used to bond a commercial composite (Filtek Supreme) to the flat surface of human dentin. Microtensile bond strength (MTBS) was tested in 1 mm2 sticks for the 5 primer/bond combinations: CC (Clearfil Bond Primer and Bond), HH (HEMA/HEMA), DD (DEBAAP/DEBAAP), HD (HEMA/DEBAAP), and DH (DEBAAP/HEMA). Prior to testing, sticks were stored in water or biofilm-inducing culture medium with S. mutans for 1 week. Confocal images and FTIR-ATR evaluation evaluated the hybrid layer of the adhesives. Results were analyzed using Student's t-test (WS, SL, DC, contact angle, FS, E, toughness), one-way ANOVA/Tukey's test for viscosity, and two-way ANOVA/Tukey's test for MTBS (95%). Results: HEMA-based materials had lower contact angle (p = 0.004), higher WS (p < 0.001), and similar SL values compared to DEBAAP (p = 0.126). FS (p = 0.171) and E (p = 0.065) dry values were similar, but after one week of water storage, FS/E dropped more significantly for HEMA materials. Dry and wet toughness was greater for DEBAAP (p < 0.001), but it also had the greatest drop (46%). Clearfil bonds had the highest viscosity, followed by DEBAAP and HEMA, respectively (p = 0.002). For the primers, HEMA had the lowest viscosity (p = 0.003). As far as MTBS, all groups tested in water were statistically different when compared with HH (p < 0.001). After storage in biofilm, DH had the highest MTBS value, being statistically different from HH (p = 0.002), CC (p = 0.015), and DD (p = 0.027). Conclusions: The addition of a diacrylamide and its association with HEMA in self-etching adhesive systems provided greater bonding stability after bacterial challenge.

Excimer-ultraviolet-lamp-assisted selective etching of single-layer graphene and its application in edge-contact devices.

Since the discovery of graphene and its remarkable properties, researchers have actively explored advanced graphene-patterning technologies. While the etching process is pivotal in shaping graphene channels, existing etching techniques have limitations such as low speed, high cost, residue contamination, and rough edges. Therefore, the development of facile and efficient etching methods is necessary. This study entailed the development of a novel technique for patterning graphene through dry etching, utilizing selective photochemical reactions precisely targeted at single-layer graphene (SLG) surfaces. This process is facilitated by an excimer ultraviolet lamp emitting light at a wavelength of 172 nm. The effectiveness of this technique in selectively removing SLG over large areas, leaving the few-layer graphene intact and clean, was confirmed by various spectroscopic analyses. Furthermore, we explored the application of this technique to device fabrication, revealing its potential to enhance the electrical properties of SLG-based devices. One-dimensional (1D) edge contacts fabricated using this method not only exhibited enhanced electrical transport characteristics compared to two-dimensional contact devices but also demonstrated enhanced efficiency in fabricating conventional 1D-contacted devices. This study addresses the demand for advanced technologies suitable for next-generation graphene devices, providing a promising and versatile graphene-patterning approach with broad applicability and high efficiency.

Water-Etched Porous Ti: Surface Manipulation of Ti Foam Fabricated by Liquid Metal Dealloying Technique.

The liquid metal dealloying (LMD) process enables the fabrication of porous metals with various chemical compositions. Despite its advantages, LMD still faces key challenges such as maintaining the high-temperature molten metal bath for a prolonged time, avoiding the use of toxic etchants, and so on. To overcome these challenges, the study develops a water-leachable and oxidation-resistant alloy melt (AM) in Ca-Mg binary system. Specifically, Ca72Mg28 eutectic AM is designed, which exhibits higher oxidation resistance and lower melting temperature compared to pure Mg, allowing LMD to be conducted in atmospheric conditions as well as temperatures >200 K lower. The AM also enables an innovative process to fabricate Ti foams with a hexagonal faceted surface structure by carefully manipulating the etching rate during the water etching process. This approach allows for the creation of foam with a surface area over 13% larger than that of foams with smooth surfaces via normal acid etching, potentially enhancing efficiency in applications such as electrodes for electrochemical systems or biomedical materials where increased cell adhesion can be beneficial. This study paves the way for efficiently manipulating the LMD process to fabricate metal foams with customized compositions and enhanced surface properties.

Spot-etch technique and other adhesive strategies for provisional veneers.

AIM: The objective of the present study was to evaluate the influence of different adhesive strategies regarding shear bond strength (SBS) of provisional resin--based materials bonded to the enamel surface as well as on the enamel surface roughness. MATERIALS AND METHODS: Bovine incisors were randomly divided into six groups (n = 10) according to the adhesive strategy used: BRControl (bis-acrylic resin); Spot-etch+BR (spot-etch + bis-acrylic resin); Spot--etchSB2+BR (spot-etch + adhesive + bis-acrylic resin); Spot-etchZ350Flow+BR (spot-etch + flowable composite resin + bis-acrylic resin); SBU+BR (universal adhesive + bis-acrylic resin); Spot-etchSBMP+Z350 (spot-etch + adhesive + composite resin). The enamel surface roughness was determined by a surface profil-ometer. An SBS test was performed in a universal testing machine, and failure modes were classified under magnification. The SBS data were analyzed by one-way analysis of variance (ANOVA). A paired t test was used for enamel surface roughness intragroup comparisons, and the Friedman one-way repeated meas-ures analysis of variance by ranks was used for differences in enamel surface roughness between groups, with the Tukey post hoc test (a = 0.05). RESULTS: BRControl had the lowest SBS values (MPa), with a significant difference (P ≤ 0.001) from the other groups. Spot-etch+BR had the highest SBS values but with no significant differences from the other groups in which the spot-etch technique was also used. Adhesive failure mode was predominant for all groups. BRControl had the lowest surface roughness difference, significantly different (P = 0.001) from all the other groups. CONCLUSIONS: Spot-etch and other adhesive strategies could be applied to increase the SBS values of provisional restorations to enamel compared with no surface pretreatment. However, the adhesive strategy may change the enamel surface roughness, revealing the importance of cleaning the tooth surface.

Clinical Effectiveness of Air Abrasion When Compared to Conventional Acid-etching Technique in Enhancing the Retention of Pit and Fissure Sealants: A Systematic Review.

Purpose: The purpose of our study was to perform a systematic review to assess and compare the effectiveness of the air abrasion technique with that of the conventional acid-etching technique performed before the placement of pit and fissure sealants. Materials and methods: A search of studies was conducted in May 2021 using PubMed, Cochrane Library, and Google Scholar databases. Clinical trials in the English language between 1997 and 2019 were included. The quality of the studies was analyzed using the Cochrane Collaboration tool. Results: The search retrieved 276 references, out of which seven studies were included for a qualitative analysis. In these seven studies, the risk of bias across the Cochrane tool's domains varied from low to high. All the included studies considered acid-etching as a comparator to air abrasion technique either used alone or as an adjunct to acid-etching technique. Conclusion: When coverage of sealants or their retentivity was compared at different time intervals, it was more in the acid-etching group than in the air abrasion group. Similarly, carious lesions were seen more in the air abrasion group than in the acid-etching group. The air abrasion technique followed by acid-etching brought superior retention properties of sealants than the acid-etching technique alone. How to cite this article: Bhadule SN, Kalaskar R, Kalaskar A, et al. Clinical Effectiveness of Air Abrasion When Compared to Conventional Acid-etching Technique in Enhancing the Retention of Pit and Fissure Sealants: A Systematic Review. Int J Clin Pediatr Dent 2024;17(3):377-384.

Rapid Fabrication of Antilunar Dust Aluminum Surface by Nanosecond Laser Etching.

Although a dust-repellent surface is desirable for lunar exploration missions, its fabrication process is complicated and time-consuming. Herein, we report a simple and fast method to fabricate a lunar dust-repellent surface by texturing on an Al substrate via nanosecond laser etching. The laser-induced photothermal effect can rapidly create hierarchical papillary structures on 25 × 25 mm Al substrates (within 30 s). Both atomic force microscopy (AFM) and in situ scanning electron microscopy (SEM) reveal that such structures enable a reduced contact area between the Al substrate and lunar dust and thus reduced adhesion. The reduced dust adhesion force of Al substrates facilitates improving their antidust performance. By optimizing processing parameters, the Al substrate etched with a laser scanning spacing of 80 µm exhibits a lower dust adhesion force (9.58 nN) due to the smallest contact area with dust. Accordingly, its static antilunar dust performance (dust coverage of 1.95%) is significantly improved compared to the pristine Al substrate (dust coverage of 12.98%). Besides, the accumulated dust on the laser-etched Al substrates with low surface adhesion force is easily cleaned up by flipping and gravity (the dust residual rates are less than 17%). The Al substrate with excellent antidust ability presents good potential for lunar exploration missions.

Quantitative evaluation of acid flow behavior in fractures and optimization of design parameters based on acid wormhole filtration losses.

The technique of matrix acidification or acid fracturing is commonly utilized to establish communication with natural fractures during reservoir reconstruction. However, this process often encounters limitations due to filtration, which restricts the expansion of the primary acid-etching fracture. To address this issue, a computational model has been developed to simulate the expansion of an acid-etching wormhole by considering various factors such as formation process, injection duration, pressure build-up, and time-varying acid percolation rate. By analyzing the pumping displacement of acid-etching wormholes, this model provides valuable insights into the time-dependent quantities of acid percolation. It has been revealed that the filtration rate of acid-etching wormholes is strongly influenced by pumping displacement, viscosity, and concentration of the acid fluid used in stimulation as well as physical properties of the reservoir itself. Notably, viscosity plays a significant role in determining the effectiveness of acid fracturing especially in low-viscosity conditions. Acid concentration within 15% to 20% exhibits maximum impact on successful acid fracturing while concentrations below 15% or above 20% show no obvious effect. Furthermore, it was found that pumping displacement has a major influence on effective fracturing. However, beyond a certain threshold (> 5.0 m3/min), increased pumping displacement leads to slower etching distance for acids used in construction purposes. The simulation also provides real-time distribution analysis for acidity levels within eroded fractures during matrix-acidification processes and quantifies extent of chemical reactions between acids and rocks within these fractures thereby facilitating optimization efforts for design parameters related to matrix-acidification.

Patterning optimization for device realization of patterned GaAsSbN nanowire photodetectors.

Vertically grown nanowires (NWs) are a research interest in optoelectronics and photovoltaic applications due to their high surface to volume ratio and good light trapping capabilities. This study presents the effects of process and design parameters on self-catalyzed GaAsSbN NWs grown by plasma-assisted molecular beam epitaxy on patterned silicon substrates using electron beam lithography. Vertical alignment of the patterned NWs examined via scanning electron microscopy show the sensitivity of patterned NW growth to the parameters of NW diameter, pitch, dose time, etching techniques and growth plan. Diameters range from 90 nm to 250 nm. Pitch lengths of 200 nm, 400 nm, 600 nm, 800 nm, 1000 nm, and 1200 nm were examined. Dry etching of the oxide layer of the silicon substrate and PMMA coating is performed using reactive ion etching (RIE) for 20 s and 120 s respectively. Comparisons of different HF etch durations performed pre and post PMMA removal are presented. Additionally, the report of an observed surfactant effect in dilute nitride GaAsSbN NWs in comparison to non-nitride GaAsSb is presented. Optimizations to patterning, RIE, and HF etching are presented to obtain higher vertical yield of patterned GaAsSbN NWs, achieving ∼80% of the expected NWµm2. Room temperature and 4 K photoluminescence results show the effect of nitride incorporation for further bandgap tuning, and patterned pitch on the optical characteristics of the NWs which gives insights to the compositional homogeneity for NWs grown at each pitch length.

Hydrogen peroxide and glucose detection using surface plasmon resonance imaging biosensor with corrodible silver thin film.

A surface plasmon resonance imaging (SPRI)-based biosensor is demonstrated for the detection of both hydrogen peroxide (H2O2) and glucose. The H2O2 to be detected acts as an oxidant and etch the silver film. This process gradually effects on resonance condition and consequently the reflected light intensity at a fixed angle. The etching rate of the silver film shows a clear relation with the H2O2 concentration. Therefore, monitoring the reflected light intensity progressively changing over a few minutes, enables accurate detection of H2O2 concentrations ranging from 0 to 200 µM (within physiological range of 0.25-50 µM), with a remarkable limit of detection (LOD) as low as 40 nM. In this regard, the behavior of the surface plasmon resonance (SPR) dip in response to the reduction of the silver film thickness is predicted by Winspall simulation software. These simulation results are in good agreement with the experimental results. Moreover, the proposed method can be applied to determine glucose concentrations ranging from 0 to 10 mM, encompassing the physiological range of 3-8 mM. This is achieved by observing the generated H2O2 through the enzymatic oxidation reaction between glucose and glucose oxidase (Gox). The sensor demonstrates remarkable sensitivity and selectivity, with a detection limit as low as 175 µM for glucose concentration. Furthermore, accurate measurement of glucose concentration in an actual human serum sample is achievable with the proposed sensor, using the standard addition method. The suggested glucose sensor shows promising prospects for use in routine glucose testing, employing a label-free, real-time, and multiplex detection approach.© 2017 Elsevier Inc. All rights reserved.

Sustained Area-Selectivity in Atomic Layer Deposition of Ir Films: Utilization of Dual Effects of O3 in Deposition and Etching.

Area-selective deposition (ASD) based on self-aligned technology has emerged as a promising solution for resolving misalignment issues during ultrafine patterning processes. Despite its potential, the problems of area-selectivity losing beyond a certain thickness remain critical in ASD applications. This study reports a novel approach to sustain the area-selectivity of Ir films as the thickness increases. Ir films are deposited on Al2O3 as the growth area and SiO2 as the non-growth area using atomic-layer-deposition with tricarbonyl-(1,2,3-η)-1,2,3-tri(tert-butyl)-cyclopropenyl-iridium and O3. O3 exhibits a dual effect, facilitating both deposition and etching. In the steady-state growth regime, O3 solely contributes to deposition, whereas in the initial growth stages, longer exposure to O3 etches the initially formed isolated Ir nuclei through the formation of volatile IrO3. Importantly, longer O3 exposure is required for the initial etching on the growth area(Al2O3) compared to the non-growth area(SiO2). By controlling the O3 injection time, the area selectivity is sustained even above a thickness of 25 nm by suppressing nucleation on the non-growth area. These findings shed light on the fundamental mechanisms of ASD using O3 and offer a promising avenue for advancing thin-film technologies. Furthermore, this approach holds promise for extending ASD to other metals susceptible to forming volatile species.

Early Peri-Implant Bone Healing on Laser-Modified Surfaces with and without Hydroxyapatite Coating: An In Vivo Study.

(1) Objective: The aim of this study was to assess the biological behavior of bone tissue on a machined surface (MS) and modifications made by a laser beam (LS) and by a laser beam incorporated with hydroxyapatite (HA) using a biomimetic method without thermic treatment (LHS). (2) Methods: Scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM/EDX) was performed before and after installation in the rabbit tibiae. A total of 20 Albinus rabbits randomly received 30 implants of 3.75 × 10 mm in the right and left tibias, with two implants on each surface in each tibia. In the animals belonging to the 4-week euthanasia period group, intramuscular application of the fluorochromes calcein and alizarin was performed. In implants placed mesially in the tibiofemoral joint, biomechanical analysis was performed by means of a removal torque (N/cm). The tibias with the implants located distally to the joint were submitted for analysis by confocal laser microscopy (mineral apposition rate) and for histometric analysis by bone contact implant (%BIC) and newly formed bone area (%NBA). (3) Results: The SEM showed differences between the surfaces. The biomechanical analysis revealed significant differences in removal torque values between the MSs and LHSs over a 2-week period. Over a 4-week period, both the LSs and LHSs demonstrated removal torque values statistically higher than the MSs. BIC of the LHS implants were statistically superior to MS at the 2-week period and LHS and LS surfaces were statistically superior to MS at the 4-week period. Statistical analysis of the NBA of the implants showed difference between the LHS and MS in the period of 2 weeks. (4) Conclusions: The modifications of the LSs and LHSs provided important physicochemical modifications that favored the deposition of bone tissue on the surface of the implants.

A pathway for detection of gastric cancer biomarkers via using a layer-by-layer coated D-shaped grinding long-period fiber grating sensor.

Gastric cancer significantly contributes to global cancer mortality, often leading to inoperable stages and high recurrence rates post-surgery. Elevated levels of G-17 and G-gly have been identified as potential risk factors, particularly in patients with duodenal ulcers. This study introduces an innovative D-shaped grinding long-period fiber grating sensor (D-LLPFGs) designed for non-invasive detection of the gastrin G-17 antigen, employing a layer-by-layer chemical self-assembly to bond G-17 antibodies onto the fiber surface through hydrogen bonding. The D-LLPFGs sensor demonstrated significant spectral shifts within 1 min of antigen-antibody interaction, highlighting its rapid detection capability. At an optimized antibody concentration of 4 µg/ml, antigen testing across different concentrations (10, 12.5, 20, 50 µg/ml) showed peak changes at 12.5 µg/ml antigen, with a 1.186 nm shift and 0.503 dB loss. The sensor exhibited a wavelength sensitivity of 0.095 nm/µg/ml, indicating its high sensitivity and potential in gastric cancer classification, diagnosis, and treatment. This research concludes that the D-shaped fiber sensor is an effective and sensitive tool for detecting G-17 antigen levels, presenting a significant advancement in non-invasive gastric cancer diagnosis. Its quick response time and high sensitivity highlight its potential for broad biomedical applications, offering a new avenue for early cancer detection and improving patient prognosis. The success of this study opens the door to further exploration and implementation of fiber optic sensors in clinical settings, marking a significant step forward in the fight against gastric cancer.