Microscopic Surface Research Articles

Comparison of Different Types of Poly-L-lactic Acid Microspheres In Vitro and In Vivo Studies

Abstract Background Biodegradable polymers are commonly used as dermal fillers in plastic surgery. Among these, poly-L-lactic acid (PLLA) distinguishes itself owing to its good biocompatibility, degradability, and ability to act as a collagen stimulator. Objectives In this study, the differential behavior of PLLA microspheres with varying microscopic morphology and surface hydrophilicity was investigated both in vitro and in vivo. Methods The introduction of short hydrophilic polyethylene glycol (PEG) chains into the PLLA molecule was employed to modify the morphology and enhance the surface hydrophilicity of the microspheres. The morphology and physicochemical properties of the PLLA and PLLA-b-PEG microspheres were characterized. Irregular PLLA particles, PLLA and PLLA-b-PEG microspheres were implanted into the subcutaneous tissue of rabbit models, and at 4, 26 and 52 weeks after implantation, biopsy samples were collected for hematoxylin and eosin (H&E) and Masson's trichrome staining to evaluate differences in the tissue response between different implants. Results The results of in vitro research demonstrated that while the addition of short-chain hydrophilic PEG afforded a smoother surface for the microspheres, it had no significant effect on the molecular weight and degradation rate of PLLA. The histological examination revealed that the PLLA-b-PEG microspheres exhibited enhanced biocompatibility compared to the pure PLLA microspheres, while the irregular PLLA particles showed the highest inflammatory response among the three materials. Conclusions In this study, we found that the properties of PLLA were improved upon modification by short-chain PEG without reducing the collagen regeneration ability, thereby affording a better histocompatibility.

ASPECTS OF SURFACE ENAMEL MINERALIZATION IN PERMANENT TEETH OF CHILDREN FROM DIFFERENT AGE GROUPS

The purpose of our study was the examination of external surface enamel mineralization in permanent teeth of children from different age groups. We examined sections of 50 extracted for orthodontic indications premolars in patients from different age groups. A study of 16 teeth was conducted in 11-13 years old children, 8 teeth were investigated in each group of 13-15 years old, as well as 9 teeth in 15-16-year-old patients. All patients were appointed with remineralization therapy during the first six months after tooth eruption fallowed by application of “Tooth Mousse” ones a day for 2 weeks every six months with appropriate monitoring. The comparison group, on the other hand, consisted from extracted teeth taken from children who were not subjected to any preventive remineralization measures. The distribution by age and the studied material was identical to the main group. Segmentation of the teeth was carried out after the tooth extraction with separation of the crown structure and further polishing of the crown using polishing brushes without pastes. Sections 0.3-0.5 mm thick were formed with a diamond disc. The enamel samples were cleaned and degreased and then examined in a polarizing microscope (Optika B-150POL-B 40x-640x Bino) at a magnification in 500 times. The description of the enamel microscopic surface was carried out according to the following parameters: surface heterogeneity, surface opaqueness/shininess, surface roughness/smoothness. The surface homogeneity was assessed by calculating the ratio of identified surface areas that visually differed from the overall enamel texture, which was characteristic of the predominant investigated surface enamel. There were criteria for evaluating the enamel surface heterogeneity according to the research data in a polarizing microscope : the presence of numerous well-defined cracks, the visualization and number of areas from which the enamel prisms extend, the presence and number of enamel surface irregularities confirmed by a change in the direction of the light beam, the percentage of surface homogeneity, which was calculated as the ratio of the area of ​​the visually homogeneous enamel surface to the area with ​​any microscopically detected changes. To assess the opacity of the enamel surface by the microscopic polarization study, the criteria of visual assessment of shiny and dark areas of interest were used. The study suggested that microscopic changes are characterized by a decrease of total number in enamel surface irregularities and an increase of its glossiness and smoothness at the approach of structural compositional stabilization at 15-16 years. The analysis also revealed that there were marked microscopic differences observed in enamel of 15-16 years old after remineralization with the "Tooth Mousse" gel and a comparison group (without remineralization therapy).The difference between them is reliable (p<0.01) according to the indicators of the relative average level of surface heterogeneity, and also statistically different from similar indicators that were registered in the age groups 11-13 and 13-15 years old (p<0.01). The gained results can be considered as the expediency grounds for implementation of dental caries prevention at the early stages of secondary mineralization (immediately after eruption) and throughout the entire period of its intensive phase, which will further contribute to the stabilization of the caries-resistant enamel.

Adaptive infrared patterns for microscopic surface reconstructions.

Multi-zoom microscopic surface reconstructions of operating sites, especially in ENT surgeries, would allow multimodal image fusion for determining the amount of resected tissue, for recognizing critical structures, and novel tools for intraoperative quality assurance. State-of-the-art three-dimensional model creation of the surgical scene is challenged by the surgical environment, illumination, and the homogeneous structures of skin, muscle, bones, etc., that lack invariant features for stereo reconstruction. An adaptive near-infrared pattern projector illuminates the surgical scene with optimized patterns to yield accurate dense multi-zoom stereoscopic surface reconstructions. The approach does not impact the clinical workflow. The new method is compared to state-of-the-art approaches and is validated by determining its reconstruction errors relative to a high-resolution 3D-reconstruction of CT data. 200 surface reconstructions were generated for 5 zoom levels with 10 reconstructions for each object illumination method (standard operating room light, microscope light, random pattern and adaptive NIR pattern). For the adaptive pattern, the surface reconstruction errors ranged from 0.5 to 0.7 mm, as compared to 1-1.9 mm for the other approaches. The local reconstruction differences are visualized in heat maps. Adaptive near-infrared (NIR) pattern projection in microscopic surgery allows dense and accurate microscopic surface reconstructions for variable zoom levels of small and homogeneous surfaces. This could potentially aid in microscopic interventions at the lateral skull base and potentially open up new possibilities for combining quantitative intraoperative surface reconstructions with preoperative radiologic imagery.

Shock-driven three-fluid mixing with various chevron interface configurations

When a shock wave crosses a density interface, the Richtmyer–Meshkov instability causes perturbations to grow. Richtmyer–Meshkov instabilities arise from the deposition of vorticity from the misaligned density and pressure gradients at the shock front. In many engineering applications, microscopic surface roughness will grow into multi-mode perturbations, inducing mixing between the fluid on either side of an initial interface. Applications often have multiple interfaces, some of which are close enough to interact in the later stages of instability growth. In this study, we numerically investigate the mixing of a three-layer system with periodic zigzag (or chevron) interfaces, calculating the dependence of the width and mass of mixed material on properties such as the shock timing, chevron amplitude, multi-mode perturbation spectrum, density ratio, and shock mach number. The multi-mode case is also compared with a single-mode perturbation. The Flash hydrodynamic code is used to solve the Euler equations in three dimensions with adaptive grid refinement. Key results include a significant increase in mixed mass when changing from a single-mode to a multi-mode perturbation on one of the interfaces. The mixed width is mainly sensitive to the density ratio and chevron amplitude, whereas the mixed mass also depends on the multi-mode spectrum. Steeper initial perturbation spectra have lower mixed mass at early times but a greater mixed mass after the reflected shock transits back across the layer.

Exploring the mechanisms of benzanilide crystal growth and morphology: Crystal surface structure, solvent diffusion and solvent-interface interactions

Flaky crystals are fragile, rendering them unsuitable for various applications including use, processing, storage and transportation. This work investigates the growth and morphology regulation mechanisms of flaky crystals using benzanilide as a model material. Initially, block-like crystals are prepared by solvent screening and cooling crystallization with its morphology greatly improved. Subsequently, growth kinetics of (111), (1–10) and (020) faces are established with crystal growth experiments. The crystal growth of (001) face is also determined to follow a two-dimensional nucleation model with the microscopic surface analysis using atomic force microscopy. The changes of the surface integration resistance and the growth step height are regarded as kinetic mechanisms of the growth behavior and crystal morphology modulation by solvent and supersaturation. Finally, the molecular mechanism of the modulation of the solvent in crystal morphology is revealed base on crystal surface structure analysis and molecular dynamics simulations. The weak solvent-interface polar interactions facilitate the incorporation of benzanilide molecules into the weak polarity (001) face, leading to the surface roughening and increased crystal thickness when employing strongly polar solvents such as acetonitrile. Unlike the former, the relatively weak hydrogen bonding interactions between solvents and strong polarity (020) face, and the higher diffusion ability of molecules promote the rapid growth and disappearance of (020) face in ethanol and acetonitrile with strong hydrogen bond formation ability. This study can contribute to a deeper understanding of the solvent effect on crystal morphology and provide guidance for optimizing crystallization conditions to obtain shape-tailored crystal products.

Investigation of the microscopic damage mechanisms in cotton fibers induced by mechanical friction

For the problem of friction damage in cotton fiber processing, a multi-scale combination of investigation methods is proposed. The surface of damaged cotton fiber is detected by relevant test means with damage features such as dislocations, defects and cracks. The internal pyranose ring and glycosidic bond fail, the crystallinity decreases, and the number of hydrogen bonds decreases. Anisotropy exists in the frictional properties of the microscopic surface of the cotton fiber. The results of molecular dynamics simulation showed that the cellulose main chain failed mainly at the glycosidic bond, and the side chain failed mainly at the hydroxymethyl functional group. Its interchain hydrogen bond O3H…O5 was the least damaged. The cellulose crystal (200) surfaces had poor abrasion resistance, and the frictional properties of each crystal surface were anisotropic. The results of the study provide a theoretical basis for improving friction and wear problems in cotton fiber processing.

Multiscale contact homogenisation: A novel perspective through the method of multiscale virtual power

The interaction between deformable bodies and rigid foundations undergoing finite strains is explored in this work with the Method of Multiscale Virtual Power, unlocking novel insights into contact homogenisation theories. The focus lies in establishing the foundational kinematical links across scales and achieving seamless homogenisation of the traction vector through rigorous duality arguments. Two distinct families of contact homogenisation models are formulated: surface–surface and surface–volume models. These families emerge from the virtual power balance established between the target macroscopic surface and the corresponding microscopic contact surface or volume. They not only represent fundamental kinematical entities at each scale but also enable the replacement of the heterogeneous contact traction distribution with a smooth, homogenised version. Microscale equilibrium problems and homogenisation relations, along with the relevant macro- and microscale quantities, are derived by means of straightforward variational arguments. Furthermore, potential finite size effects are addressed in the homogenised response, enhancing the reliability and applicability of the strategy across diverse scenarios. Promising submodels have been identified within both families, broadening the understanding of multiscale contact phenomena and including existing models as particular cases. The proposed continuum-based variational families of models naturally lead to generic finite element-based frameworks for contact homogenisation of heterogeneous solids, as described in a forthcoming paper.

Influence of TiO2-MWCNTs nanohybrid material on the corrosion resistance of epoxy low-zinc coatings

Aiming to improve the corrosion resistance of epoxy low-zinc coatings in marine environments, TiO2-MWCNTs nano-hybridized materials were prepared by sol-gel method in this study, and different contents of reinforcing phases were implanted as to improve the anticorrosive properties of epoxy low-zinc coatings. Characterization of the microscopic morphology, physical phase composition and chemical structure of the TiO2-MWCNTs materials demonstrated that the TiO2 hybridization was successful and the loading of TiO2 improved the dispersion of MWCNTs. To investigate the effect of the additive reinforcing phase on the mechanical and corrosion resistance of the coatings by characterizing the coating microscopic morphology, surface wettability, substrate adhesion, and impedance changes at different immersion times. The above results demonstrated that the epoxy composite coating had lower surface energy and 16 % larger surface contact angle compared with the pure epoxy low-zinc coating; the 0.4 wt% TiO2-MWCNTs/epoxy composite coating had the highest adhesion of 6.52 MPa. The electrochemical test results indicated that the TiO2-MWCNTs/epoxy low-zinc composite coating had the largest self-corrosion potential, the smallest self-corrosion current density of 4.538 μA/cm2, and the largest impedance of 242.3 KΩ/cm2. The addition of TiO2-MWCNTs reinforcing phase significantly extended the barrier protection time of the epoxy low zinc coating and maintained good corrosion resistance throughout the immersion cycle.

Multi-Scale Study on the Effect of Snowmelt Salt on the Interface Adhesion of Rubberized Asphalt–Steel Slag

To explore the effect of snowmelt agent on the adhesion of the rubberized asphalt–steel slag interface, the adhesion of the rubberized asphalt–steel slag interface under different concentrations of snowmelt agent was studied. The macroscopic fracture characteristics of the steel slag-rubberized asphalt mixture under different concentrations of snowmelt salt were studied. The surface energy of steel slag and rubberized asphalt after the action of different concentrations of snowmelt salt was tested at the microscopic scale, and then their adhesion was calculated. It was used to study the microscopic surface interaction under the action of snowmelt agents. At the molecular scale, the interface models of rubberized asphalt–NaCl solution–Ca3SiO5 were constructed, and the interaction between steel slag and asphalt under different concentrations of snowmelt agent was studied. The results show the following: when the concentration of snowmelt agent is 8%–12%, the fracture of the rubberized asphalt–steel slag mixture is more inclined to brittle fracture, and the failure speed is faster; the adhesion of steel slag-rubberized asphalt is weakened under the action of the snowmelt agent, but it can still maintain good adhesion; before the concentration of snowmelt agent reached saturation, the adhesion property of steel slag-rubberized asphalt decreases with the increase of snowmelt agent concentration; when the concentration of snowmelt agent reached saturation, NaCl precipitates and adheres to the molecular surface of steel slag, which enhances the interaction between steel slag and rubberized asphalt; the inflection point with salt concentration is related to the solvent precipitated from the solution.

Targeted Microforming of Borosilicate Glass Induced by a Laser‐Ablation‐Free Process Using Femtosecond Pulses

AbstractThe use of ultrashort pulse lasers opens up a wide range of possibilities for processing dielectric materials. The present study focuses on the investigation of the ablation‐free microscopic surface modification of borosilicate glass using femtosecond laser radiation (350 fs at 515 nm wavelength) in a scanning machining process. Furthermore, its aim is to analyze the relationship between the laser process parameters and the microscopic changes in the surface topography observed. The characteristic of the generated surface structure, which takes place below the ablation threshold, shows both elevations and depressions within the irradiated field (2 × 2 mm2). The realized structures reach a profile height Peak‐to‐Valley (PV) of up to 10 µm. The amount of surface deformation depends on the selected parameters such as laser fluence, number of passes, and scanning strategy. The microdeformation is detected on both the top and bottom sides of the processed glass material with a thickness ≤1 mm. The influence of the temporal and spatial energy distribution on the material modification is discussed, demonstrating the possibilities of microforming of silicate glasses using ultrashort pulsed laser radiation.

Microscopic characteristics of peri- and postmortem fracture surfaces

This study investigated if microscopic surface features captured with a scanning electron microscope (SEM) effectively discriminate fracture timing. We hypothesized that microscopic fracture characteristics, including delamination, osteon pullout, and microcracks, may vary as bone elasticity decreases, elucidating perimortem and postmortem events more reliably than macroscopic analyses. Thirty-seven unembalmed, defleshed human femoral shafts from males (n=18) and females (n=2) aged 33–81 years were fractured at experimentally simulated postmortem intervals (PMIs) ranging from 1 to 60 warm weather days (250–40,600 ADH). A gravity convection oven was used to approximate tissue decomposition at 37 C and 27 C, and the resulting heat-time unit (accumulated degree hours, or ADH) was used to examine fractures in elastic/wet versus brittle/dry bone. The bones were fractured with a drop test frame using a three-point bending setup, sensors were used to calculate fracture energy, and high-speed photography documented fracture events. The following data were collected to relate fracture appearance to the biomechanical properties of bone: PMI (postmortem interval) length in ADH, temperature, humidity, collagen percentage, water loss, bone mineral density, cortical bone thickness, fracture energy, age, sex, cause of death, and microscopic fracture feature scores. SEM micrographs were collected from the primary tension zones of each fracture surface, and three microscopic fracture characteristics were scored from a region of interest in the center of the tension zone: percentage of delaminated osteons, percent osteon pullout, and number of microcracks. Multiple linear regression showed that microscopic fracture surface features are strong predictors of ADH (adjusted R-squared=0.67 for the 0 – 40,000 ADH samples; adjusted R-squared=0.92 for the 0–16,000 ADH samples). Osteon pullout is the single best predictor of ADH. Additionally, water loss is the primary driver of bone elasticity changes in low ADH samples, while collagen fibers appear to remain intact until later in the postmortem interval (approximately 40,000 ADH in this study). The results of this study indicate microscopic fracture surface analysis detects the biomechanical effects of decreased elasticity more reliably and with greater sensitivity than macroscopic analysis.

High-capacity and high-stability capacitive desalination with dual redox-active MnCo2S4/g-C3N4 heterojunction electrode

Capacitive deionization (CDI) utilizing dual redox-active electrodes has shown significant promise in desalinating low-concentration brackish waters, which is crucial for addressing global freshwater shortages. However, improvements in salt adsorption capacity and long-term operational stability are still required. In this study, we introduce, for the first time, a binary metal sulfide MnCo2S4/g-C3N4 (MCS-CN) heterojunction as a CDI electrode. The innovative integration of dual redox-active centers and heterojunction structures in the MCS-CN composite electrodes underscores their potential for achieving both high capacity and stability in capacitive desalination applications. The microscopic morphology, crystal structure, pore structure, and surface valence properties of the MCS-CN heterojunction composite materials were extensively characterized using various analytical techniques. In-situ X-ray diffraction, refined ex-situ X-ray photoelectron spectroscopy, three-electrode electrochemical analysis, and theoretical calculations were employed to elucidate the electrosorption and desorption mechanisms of sodium ions with the MCS-CN electrodes and to clarify the enhanced desalination performance of the binary metal sulfide-based heterojunction structure. As a result, the optimal MCS-CN-40 electrode exhibited the highest salt removal capacity of 71.64 mg g−1 and maintained stable desalination performance over 100 cycles in a 500 mg L−1 NaCl solution. This innovative approach provides a noval perspective for developing heterojunction electrodes with high redox activity and efficient desalination performance.

A tutorial on the physics of light and image shading.

This paper provides an overview of the many different ways that light interacts with surfaces in the natural environment to provide useful information for visual perception. It begins with a discussion of how the concept of light has evolved over the course of human history. It then considers a wide variety of optical phenomena including Lambert's laws of illumination, the effects of microscopic surface structure on patterns of reflection, the bidirectional reflectance distribution function, the refraction of transmitted light, chromatic dispersion, thin film interference, sub-surface scattering, the Fresnel effects, indirect illumination from multiple reflections, caustics, and the structure of the light field. The primary goal of this discussion is to provide the necessary background information to help students and young researchers more easily understand the scientific literature on the perception of 3D shape and material properties from patterns of image shading.

A comparison of several separation processes for eggshell membrane powder as a natural biomaterial for skin regeneration.

Numerous studies have focused on skin damage, the most prevalent physical injury, aiming to improve wound healing. The exploration of biomaterials, specifically eggshell membranes (ESMs), is undertaken to accelerate the recovery of skin injuries. The membrane must be separated from the shell to make this biomaterial usable. Hence, this investigation aimed to identify more about the methods for membrane isolation and determine the most efficient one for usage as a biomaterial. For this purpose, ESM was removed from eggs using different protocols (with sodium carbonate, acetic acid, HCl, calcium carbonate, and using forceps for separation). Consequently, we have examined the membranes' mechanical and morphological qualities. According to the analysis of microscopic surface morphology, the membranes have appropriate porosity. MTT assay also revealed that the membranes have no cytotoxic effect on 3T3 cells. The results indicated that the ESM had acquired acceptable coagulation and was compatible with blood. Based on the obtained results, Provacol 4 (0.5-mol HCl and neutralized with 0.1-mol NaOH) was better than other methods of extraction and eggshell separation because it was more cell-compatible and more compatible with blood. This study demonstrates that ESMs can be used as a suitable biomaterial in medical applications.

Effects of the Lactobacillus fermentation on Dendrobium officinale polysaccharide: Structural, physicochemical properties and in vitro bioactivities

Structural modification of polysaccharides using microbial fermentation is of great interest due to its specificity and environmental friendliness. The aim of this research was to compare structure, physicochemical properties and in vitro bioactivities of the Dendrobium officinale polysaccharides before and after fermentation using Lactobacillus paracasei and Lactobacillus acidophilus. The main fractions of crude polysaccharides from unfermented Dendrobium officinale (DOP-1A) and fermented Dendrobium officinale (FDOP-1A) were obtained by column chromatography purification. Compare to DOP-1A, the molecular weight of FDOP-1A was significantly reduced (from 412.566 to 25.161 kDa), smaller particle size (from 21.05 to 19.35 μm) and lower apparent viscosity. Although the microscopic surface morphologies of DOP-1A and FDOP-1A were significantly different, neither formed a triple-helix structure. Additionally, FDOP-1A contained more t-Manp and less 4-Manp, and interestingly the (1 → 4)-β-D-Glcp glycosidic bond site between the repeat units →4)-2-O-acetyl-β-D-Manp-(1 → 4)-β-D-Glcp-(1→ and →4)-β-D-Manp-(1 → 4)-β-D-Glcp-(1→ was cleaved. Moreover, FDOP-1A exhibited excellent scavenging capacity for ABTS+, DPPH, hydroxyl radicals and inhibited Nitric Oxide production by RAW 264.7 macrophages, thereby demonstrating effective antioxidant and anti-inflammatory effects. In conclusion, Lactobacillus fermentation could improve physicochemical properties and enhance biological activities of Dendrobium officinale polysaccharide, which has potential prospects for development and application in dietary supplements.

Effect of phytic acid on chemical, structural, and mechanical characteristics of nickel–titanium endodontic files

This study investigated phytic acid (IP6) effect on chemical, structural, and mechanical characteristics of nickel–titanium (NiTi) files. The tested files were equally divided into groups according to the immersion protocol: sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), IP6, EDTA followed by NaOCl, and IP6 followed by NaOCl. These groups were then compared in terms of Ni, Ti, and chromium (Cr) ions release from the files. Microstructural changes using field emission scanning electron microscope (Fe-SEM) and energy dispersive X-ray spectroscopy (EDX) and surface roughness were analyzed. The mechanical characterization was conducted using cyclic fatigue resistance test. Fractured segments were scanned under SEM. Statistical analysis was performed using one-way ANOVA, Tukey test, Kruskal–Wallis test and Mann–Whitney U test. Results showed that NaOCl caused significant release of Cr, followed by IP6 and EDTA (P < 0.05). When files were pre-immersed in EDTA, NaOCl tended to induce less release of Ti and Cr. EDX evaluation revealed that the main surface elements were Ni, Ti, carbon, and oxygen. EDTA group contained the highest amount of carbon, while the control group showed the lowest. Surface roughness evaluation revealed no significant differences between groups despite the minor increases after immersion in certain groups. Black areas were observed in the NaOCl group which indicated corrosion. However, the cyclic fatigue test showed no significant differences between the groups.

Investigation of the milled surface quality of SiCp/Al composite materials with a moderate SiCp volume fraction

Silicon carbide particle–reinforced aluminum matrix (SiCp/Al) composite materials are challenging to machine, leading to significant surface quality issues arising during milling. In this study, a single-factor experiment was conducted using carbide-coated tools to mill SiCp/Al composite materials with a 45% volume fraction of silicon carbide particles (SiCps). Scanning electron microscopy, roughness measuring instruments, and a three-dimensional optical profiler were employed to investigate the formation mechanisms of the machined surface morphologies, as well as the effects of milling parameters (milling speed, feed per revolution, and milling depth) on the surface micro-morphology of the SiCp/Al composite materials. This study assessed the suitability of various roughness characterization parameters for evaluating the milled surface of SiCp/Al composite materials, including the two-dimensional profile arithmetic mean deviation (Ra), profile root mean square deviation (Rq), and microscopic surface roughness 10-point height (Rz), as well as the three-dimensional arithmetic mean deviation of the surface profile (Sa), and root mean square deviation of the surface profile (Sq) roughness characterization parameters to evaluate the milled surface of the SiCp/Al composite materials. The findings suggest that the three-dimensional roughness characterization parameters more accurately reflected the changes in the surface roughness than the two-dimensional ones. When the milling speed increased from 0.05 to 1.2 mm/rev, Sa first decreased from 0.514 to 0.498 µm and then increased to 0.537 µm, while Sq first decreased from 0.637 to 0.616 µm and then increased to 0.658 µm. Ra, Rz, and Rq all increased with higher values of feed per revolution and milling depth.

Three-Dimensional Optical Study on the Effects of Microwave Glazing on Surface Roughness of Zirconia-Reinforced Glass Ceramic.

BACKGROUND This 3-dimensional (3D) optical study aimed to evaluate the effects of microwave glazing on the surface roughness of zirconia-reinforced glass. Glazed surfaces of ceramic provide a smooth and esthetically superior restoration. There are many methods of glazing. However, this study aims to evaluate the effect of microwave glazing on ceramic restorations over conventional oven and hand polishing. MATERIAL AND METHODS A sample size of 90 ceramic material tiles was derived according to the standard sample size formula. The 3 dental ceramics used were IPS e.max CAD (lithium disilicate ceramic; IvoclarVivadent), Suprinity (zirconia-reinforced lithium silicate; VITA Zahnfabrik), and Celtra Duo zirconia-reinforced lithium silicate; Dentsply Sirona). Each group was further divided equally to undergo conventional oven glazing, hand polishing, and microwave glazing. The final glazed surfaces were then evaluated for surface roughness with the Ra parameter, using a Contour GT 3D Optical Microscope (Bruker) and 3D non-contact surface metrology with interferometry. RESULTS The ANOVA test for intergroup comparison showed microwave glazing was a significantly better glazing method than conventional oven and hand polishing (P<0.05). A statistically significant difference was shown between conventional and microwave glazing; however, the difference was greater between conventionally glazed and hand-polished specimens. Furthermore, a highly significant difference between microwave-glazed and hand-polished specimens was observed. CONCLUSIONS Results showed that irrespective of the ceramic, microwave-glazed ceramics were better than traditional oven-glazed ceramics, and hand-polishing resulted in a rougher surface than glazing. Irrespective of the surface treatment methods, IPS e.max CAD ceramic showed a relatively smoother surface than did Suprinity and Celtra Duo.

Study on the influence of FCC waste catalysts on the interaction ability between asphalt and fillers

Fluid catalytic cracking (FCC) waste catalysts produced by petroleum cracking contain many harmful substances, such as heavy metals, and improper treatment can lead to environmental pollution. To solve this problem, this study investigated four types of FCC (LM, SH, A, SL) waste catalyst as a substitute filler for limestone mineral powder and examined their interactions with asphalt and fillers. The X-ray fluorescence (XRF), scanning electron microscope and specific surface area tests were conducted to compare the performance of FCC waste catalyst and fillers. Meanwhile, the effects of FCC waste catalyst on asphalt mastic composed of limestone mineral powder and asphalt were evaluated using surface energy, interaction parameters, and FTIR. Results show that there is little difference in the main components of the four waste FCC catalysts and limestone mineral powder. However, the surface roughness and specific surface area of the FCC catalysts are significantly greater than those of limestone. Moreover, the addition of FCC waste catalyst can improve the adhesion of asphalt with fillers and aggregates, and significantly enhance the interaction capabilities between the filler and the base asphalt, especially for SH. FTIR analysis confirms that the aforementioned improvements are achieved through physical interactions. This study reveals the effects of different FCC waste catalysts on asphalt mortar, and provides a theoretical basis for promoting the practical application of FCC waste catalysts in road engineering.

(Nanocarbons Division SES Young Investigator Award) Surface Chemistry of Nanocarbon Field-Effect Transistors: From Fundamental Physics to Biosensing

Conductive carbon nanomaterials are particularly well-suited to form field-effect biosensors (bioFETs) because they are stable in aqueous media and can be chemically coupled to biomolecules. Their reduced dimensionality, either 2D (graphene) or 1D (carbon nanotubes), is key to their sensitivity: because they are entirely surfaces, these materials present remarkable electrical transport properties that are easily altered by microscopic surface interactions. Biochemical processes occurring in close proximity to their surface can therefore be transduced as changes in their electrical conductance. Selectivity for specific biochemical events, however, must be engineered via functionalization of the nanomaterial, i.e. by modifying its surface with bioactive or biorecognition elements (e.g., antibodies, aptamers, enzymes, polymer layer). Our group recently analyzed a corpus of studies presenting graphene field-effect transistors (GFETs) as bioanalytical sensors for the quantitative detection of biomarkers in the form of nucleic acids, proteins, ions or small molecules [1]. We found a striking variance in the reported sensing performance between these studies, that could not be explained by controlling for differences in graphene material, analyte type and for evolution over the years. Our hypothesis is that the lack of microscopic control on the biointerface is likely the most important source of variation in such bioFETs, highlighting the critical need to improve our knowledge and control of the functionalization of nanocarbon materials.In this talk, I will discuss our work investigating the interplay between surface chemistry and electrical properties in nanocarbon field-effect transistors. In the first part, I will focus on covalent additions using aryldiazonium salts. I will review what we have learned on the fundamental physics of this chemistry from experiments and simulations on carbon nanotube devices [2-5], in particular on its disruptive character because of the formation of sp 3 defects in the carbon lattice. More recently, we investigated this same chemistry on GFET devices and observed a heterogeneous response in their electrical conductance. Aiming to solve this, we developed a novel approach to precisely trigger and stop the reaction in situ using the applied gate voltage [6], enabling unprecedented control on the functionalization rate and yield on GFETs. In the second part, I will describe our ongoing efforts to characterize and control the biofunctionalization of GFETs through non-covalent pyrene derivatives, using a combination of electrical measurements, microscopy and spectroscopy techniques, and theoretical simulations. Finally, I will discuss our ongoing translational projects in oncology, on adapting nanocarbon-based bioFETs in cancer diagnostics applications.[1] Béraud et al, Analyst 146 (2), 403-428 (2021)[2] Bouilly et al, Applied Physics Letters 101 (5), 053116 (2012)[3] Bouilly et al, ACS nano 9 (3), 2626-2634 (2015)[4] Bouilly et al, Nano Letters 16 (7), 4679-4685 (2016)[5] Côté et al, Physical Chemistry Chemical Physics 24 (7), 4174-4186 (2021)[6] Bazan et al, Nano Letters 22 (7), 2635-2642 (2022)