Micro PIXE mapping proves a differential distribution and concentration of trace elements in fungal structures of Rhizophagus intraradices.

Arbuscular mycorrhizal (AM) fungi can sequester different potentially toxic elements, such as trace elements (TEs), within their structures to alleviate the toxicity for its host plant and themselves. To elucidate the role of AM fungi in TEs immobilization in the rhizosphere of host plants, it is important to know the TEs distribution in AM fungal structures. In the present study, we investigated the distribution and concentration of TEs within extraradical spores and mycelium of the AM fungus Rhizophagus intraradices, collected from the rhizosphere of Senecio bonariensis plants grown in a soil polluted with multiple TEs, by using Particle-Induced X-ray Emission with a micro-focused beam (micro PIXE). This technique enabled the simultaneous micrometric mapping of elements in a sample. The calculated values were compared with those in the polluted substrate, measured by the Wavelength Dispersive X-ray Fluorescence technique. The highest concentrations of Fe, P, Ti, Mn, Cr, Cu and Zn were found in AM fungal spores, where they were accumulated, while extraradical mycelium was enriched in Cu. Finally, we demonstrated that AM fungi can simultaneously accumulate high amounts of different TEs in their structures, thus reducing the toxicity of these elements to its host plant.

Green tech soil analysis: a comparison of potentially toxic element contents among urban, agricultural, and gold mining areas in the Eastern Brazilian Amazon.

Artisanal gold mining can lead to soil contamination with potentially toxic elements (PTEs), necessitating soil quality monitoring due to environmental and human health risks. However, determining PTE levels through acid digestion is time-consuming, generates chemical waste, and requires significant resources. As an alternative, portable X-ray fluorescence (pXRF) offers a faster, more cost-effective, and sustainable analysis. This study compared total As, Ba, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Ti, V, and Zn obtained from pXRF with their pseudo-total contents obtained through acid digestion (USEPA method 3051A) in areas influenced by artisanal gold mining in the Eastern Amazon, Brazil. pXRF data and machine learning algorithms were used to predict extractable Cu, Fe, Mn, and Zn. Linear regression models were fitted to compare the two methods, and random forest and support vector machine techniques were used to predict extractable contents. The best regression model fits for the pseudo-total PTE contents were those for Cu, Fe, Mn and Pb in agricultural areas (R2 > 0.80); Fe and Mn in gold mining residue (R2 > 0.70); and Ba, Cu and Mn in urban areas (R2 > 0.80). The best models for predicting the extractable PTE contents were those for Cu (R2 = 0.72; RMSE = 2.58 mg dm-3) and Zn (R2 = 0.71; RMSE = 1.44 mg dm-3) in agricultural areas and for Zn (R2 = 0.72; RMSE = 0.43 mg dm-3) in gold mining residue. The results demonstrated that pXRF can characterize and predict PTE contents in mining-impacted areas, offering a sustainable approach to soil quality analysis.

Anthropogenic modification of a giant ground sloth tooth from Brazil supported by a multi-disciplinary approach.

Identifying evidence of human modification of extinct animal remains, such as Pleistocene megafauna, is challenging due to the similarity of anthropogenic and non-anthropogenic taphonomic features observed under optical microscopy. Here, we re-investigate a Late Pleistocene ground sloth tooth from northeast Brazil, previously suggested as human-modified based only on optical observation. To characterize the macro- and micro-morphological characteristics of the marks preserved in this tooth and evaluate potential human modification, we used stereomicroscope and scanning electron microscopy (SEM) supplemented by energy dispersive spectroscopy (EDS), UV photoluminescence (UV/PL), synchrotron-based X-ray fluorescence (SR-XRF), and synchrotron micro-computed tomography (SR-µCT). These methods allowed us to discriminate non-anthropogenic taphonomic features (root and sedimentary damage), anthropogenic marks, and histological features. The latter shows the infiltration of exogenous elements into the dentine from the sediments. Our evidence demonstrates the sequence of anthropogenic and non-anthropogenic taphonomic modification of this tooth and supports its initial intentional modification by humans. We highlight the benefits of emerging imaging and spectral imaging techniques to investigate and diagnose human modification in fossil and archaeological records and propose that human modification of tooth tissues should be further considered when studying possibly anthropogenically altered fossil remains.

Characteristics of the Integument of Phyllomedusa burmeisteri (Anura, Phyllomedusidae) and Boana semilineata (Anura, Hylidae) Males Can Contribute to Understanding its Relation to Habitat.

The integument of anurans plays vital physiological roles, crucial for understanding the species' survival in their environment. Despite its significance, there are few studies describing the cutaneous morphology of anurans from the Brazilian Atlantic Forest. This study aimed to characterize the integument of Phyllomedusa burmeisteri and Boana semilineata in males using microscopic and histochemical approaches. Histological sections were stained with various dyes, and additional fragments underwent electron microscopy and energy-dispersive X-ray spectroscopy. Results showed different projections on the dorsal and ventral regions of males from these species, without the Eberth-Katschenko layer. Differences in the arrangement of chromatophore cells in regions with varying solar incidence were observed in the spongy dermis. Various gland types were identified, aiding taxonomic differentiation and validation of behavioral data. Both species had seromucous and granular glands, while only P. burmeisteri displayed lipid glands. Histochemical analysis revealed higher production of polysaccharides and proteins, contributing to the integument's moisture and protection. Lipid secretions in P. burmeisteri helped waterproof the integument more effectively against desiccation. This study concludes that analyzing anuran integument provides valuable insights into their behavior, with integument composition potentially influenced by habitat choice among different species.

Examining the Physicochemical Composition of Three Bioceramic Putties for Endodontic Use.

OBJECTIVE: This study aimed to address the lack of comparative analyses of newly developed bioceramic materials by examining the chemical composition, thermodynamic profile, and microscopic surface features of three bioceramic putties: EndoSequence BC Root Repair Material Fast Set Putty (ESRRM-FS), BIO-C Repair (BCR), and Cera Putty (CP). METHODS: Samples of each of the three bioceramic putty obtained directly from manufacturers were prepared for analysis of physicochemical composition and microscopic features by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) imagery, and energy-disper-sive X-ray spectroscopy (EDS). The data obtained was qualitatively and statistically analysed. Statistical signif-icance was determined at p≤0.05. RESULTS: DSC analysis indicated a standard polymeric vehicle for BCR and CP, coinciding with the polyethene glycol (PEG) thermal profile; the polymeric vehicle in ESRRM-FS remains to be identified. The material with the highest heat capacity was CP (p<0.05), followed by ESRRM-FS and BCR. TGA revealed an inflexion point at 394.12 ºC for ESRRM-FS, which may correspond to the mass loss of dihydroxylation of calcium hydroxide. A more homogenous structure was observed in scanning electron microscopy (SEM) images for ESRRM-FS. EDS analysis indicated BCR had minimal amounts of aluminium (2.06+-0.44%) and a lower percentage of cal-cium than ESRRM-FS (9.11+-1.38% vs. 11.3+-0.87%). CP was composed of aluminium (49.35+-7.01%), carbon (30.65+-5.62%), and oxygen (16.75+-2.44%); no silicon was identified. ESRRM-FS had no aluminium present and the highest calcium percentage (11.3+-0.87%) (p<0.05). CONCLUSION: BCR is a Portland cement-derived material with a lower percentage of calcium than ESRRM-FS and minimal amounts of aluminium. CP is a monocalcium aluminate cement, mainly composed of aluminium, carbon, and oxygen. ESRRM-FS is a biphasic material with the highest calcium percentage among all materials studied and no aluminium.

Effect of a novel low-concentration hydrogen peroxide bleaching gel containing nano-sized sodium trimetaphosphate and fluoride.

OBJECTIVES: To evaluate in vitro the effects of nano-sized sodium trimetaphosphate (TMPnano) and sodium fluoride (F) added to a 17.5 % hydrogen peroxide (H2O2) bleaching gel on the color change, enamel mechanical and morphological properties, and H2O2 transamelodentinal diffusion. MATERIALS AND METHODS: Bovine enamel/dentin discs (n = 180) were divided according to the bleaching gel: 17.5 % H2O2 (17.5 % HP); 17.5 % H2O2 + 0.1 % F (HP/F); 17.5 % H2O2 + 1 % TMPnano (HP/TMPnano); 17.5 % H2O2 + 0.1 % F + 1 % TMPnano (HP/F/TMPnano) and 35 % H2O2 (35 % HP). The gels were applied for 40 min on three sessions, each session spaced 7 days apart. The total color change (ΔE*ab) according to the Commission Internationale de l'Eclairage (CIE) L*a*b* color change measured by CIEDE2000 (ΔE00), whitening index (ΔWID), surface hardness (SH), surface roughness (Ra), cross-sectional hardness (ΔKHN), and transamelodentinal diffusion were assessed. Enamel surfaces were examined using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDS) analysis. The data were analyzed using ANOVA, followed by the Student-Newman-Keuls test (p < 0.05). RESULTS: ΔE*ab, ΔE00, and ΔWID values were comparable among the gels that produced a bleaching effect post-treatment (p < 0.001). The HP/F/TMPnano group exhibited lower mineral loss (SH and ΔKHN), Ra, and H2O2 diffusion compared to the 17.5 % HP and 35 % HP groups, which had the highest values (p < 0.001). SEM/EDS analysis revealed surface changes in all bleached groups, though these changes were less pronounced with F/TMPnano. CONCLUSIONS: The 17.5 % HP gel containing F/TMPnano maintains the bleaching effect while reducing enamel demineralization, roughness, H2O2 diffusion, and enamel morphological changes. CLINICAL RELEVANCE: Low-Concentration H2O2 bleaching gel containing F/TMPnano can be used as a novel approach to enhance safety and maintain the performance of aesthetic effects.

Evaluation of adhesive properties and enzymatic activity at the hybrid layer of a simplified adhesive loaded with 0.2 % Cu and 5 % ZnO nanoparticles: A Randomized Clinical Trial and ex vivo analysis.

OBJECTIVE: The aim of this study was to evaluate the effect of an adhesive loaded with 0.2 % copper (Cu) and 5 % zinc oxide (ZnO) nanoparticles (Nps) on its adhesive properties and enzymatic activity at the hybrid layer ex vivo in a randomized clinical model. METHODS: Fifteen patients participated in this study, and a total of 30 third molars were used. Occlusal cavities (4 × 4 × 2 mm) were made in each tooth, and randomly divided into 2 groups: (i) Experimental group: commercial adhesive loaded with 0.2wt % CuNps and 5wt % ZnONps; and (ii) Control Group: non-loaded commercial adhesive. Teeth were restored with resin composite. Thirty days later, extractions were performed. Extracted teeth were longitudinally sectioned. Nps in powder were characterized by field emission scanning electron microscope (FE-SEM) and energy dispersive X-ray (EDX) analysis. Microtensile bond strength (µTBS), degree of conversion (DC), and nanoleakeage (NL) tests were executed. In situ zymography (Zym) was performed to evaluate the gelatinolytic activity at the hybrid layer. Student's t-test (α = 0.05) was applied for all tests. RESULTS: µTBS and DC did not show significant differences (p > 0.05) between both groups. However, NL and gelatinolytic activity at the hybrid layer showed significant values (p < 0.05) for experimental group in comparison with control group. CONCLUSION: The addition of 0.2 % CuNps and 5 % ZnONps to a universal adhesive decreases NL and gelatinolytic activity at the hybrid layer, without jeopardizing its adhesive properties. SIGNIFICANCE: This randomized clinical trial with ex vivo analysis demonstrate that a commercial adhesive modified with 0.2wt % Cu and 5wt % ZnO Nps that does not affect its adhesive properties, reducing gelatinolytic activity and nanoleakage at the hybrid layer, which should contribute to an improvement of long term bonding-dentine clinical performance.

An investigation on the physical properties of cementitious pastes modified with low dosage of waste glass powder and silica fume.

Portland cement (PC) production is among the industrial activities that most emit harmful gases. Its replacement to green binders turns into a timely issue to face the global restrictions due to climate changes. In this study, some properties of cementitious pastes prepared with waste packing glass powder (GP) and silica fume (SF) were characterized in line with a prefixed alkaline equivalent limit. These materials were obtained in Northeastern Brazil. Grinding operations used to produce GP into four size ranges ([45-75] µm, < 45 µm; [25-45] µm, < 25 µm) were disclosed. X ray diffraction showed that GP and SF substitutions did not change the hydration products commonly observed in PC pastes. The portlandite content measured with thermogravimetry was affected by GP size in both unitary and binary substitutions. The compressive strength measured after 56 days of curing was dependent on portlandite and void index contents measured in hardened pastes. Scanning electron microscopy coupled to energy dispersive spectroscopy were useful to show the effect of the particle size on the pozzolanic activity. It was found that 5% of PC replacement for GP < 25 µm was enough to raise the compressive strength by ~5%. For binary substitution, the strength increasing was ~ 20 %. The collectors of solid residues are the main players of waste glass recycling in Brazil. It is expected that the results of this study contribute to take out these workers from the fringes of the citizenship.

Gamma-rays and X-rays spectrometries applied to evaluate soil redistribution.

This work responds to the growing global demand for food, which requires improvements in agricultural production and sustainable management of natural resources. The focus is on soil erosion as a critical element in preserving agricultural productivity. From this perspective, the levels of radionuclides and chemical elements present in the soil, quantified through Gamma-Rays Spectrometry (GRS) and Energy Dispersive X-ray Fluorescence (EDXRF), were used to investigate soil redistribution over time. 27 soil samples ranging from 0 to 30 cm in depth were collected in an agricultural plot located in southern Brazil. Quantitative analysis indicated high mean concentrations of Fe (161 ± 7 gkg-1), Al (110 ± 17 gkg-1), Ca (2.6 ± 0.5 gkg-1), Mn (2.4 ± 0.3 gkg-1) and K (543 ± 165 mgkg-1) in comparison with the other detected elements. The quantification of 137Cs provided a mean inventory of 27 ± 17 Bqm-2. Using the proportional model, an estimated gross erosion rate of 28.2 tonha-1year-1 and a net soil deposition of 6.6 tonha-1year-1 were calculated. Therefore, a net soil loss of 21.6 tonha-1year-1 was experienced within the agricultural plot studied. The data set combination of both techniques with Principal Component Analysis (PCA) revealed correlations between the variables studied and the soil erosion dynamics. The PCA showed a tendency to separate the samples according to their sampling depth. Moreover, 137Cs behavior in soil proved to be similar to the behavior of elements found in fertilizers, like K. On the other hand, the individual influence of 137Cs was not enough to cause significant changes in the samples distribution in the scores plot, highlighting EDXRF as a promising technique to complement soil erosion studies.

Technological characterization and environment-friendly possibilities to reuse water treatment sludge in building materials.

Water treatment plants (WTPs) produce thousands of tons of sludge annually, which is destined for landfill disposal, an environmentally and economically impractical alternative. Chemical, mineralogical, and morphological characterization besides environmental classification has been performed for WTP sludge and it was evaluated application potential in building materials, from a literature review. The characterization was carried out by X-ray fluorescence spectrometry, X-ray diffraction, scanning electron microscopy analysis, and leaching and solubilization tests. The results show that the presence of activated charcoal residues from water treatment in one type of sludge was of little relevance for changes in the properties of the waste. Both sludges have a wide range of particle sizes, consisting mainly of silica, aluminum and iron oxides, as well as kaolinite, quartz, and iron minerals. Special attention must be paid to the solubilization of metallic contaminants to avoid contamination risks and order to make the application safer and more effective, it is necessary to study deeply ways to inert the WTP sludge. The sludges studied have a high potential for application in ceramic products, mortars, geopolymers and concrete paving stones. Depending on the type of building material, different contents of sludge in natural or calcined state can be incorporated.

Analysis of the Chemical Composition, Morphological Characterization, and Porosimetry of Allograft and Comparison with Xenograft for Dental Applications / Análisis de la Composición Química, Caracterización Morfológica y Porosimetría de Aloinjerto y Comparación con Xenoinjerto para Aplicaciones Odontológicas

SUMMARY: Tissue engineering aims to fabricate a scaffold that exhibits a suitable surface topography for a desired cellular response. Therefore, a study analyzing the characteristics of bone grafts is important for future research directions. This work aims to analyze the physical-chemical characteristics of commercially available bone grafts of human and bovine origin for dental use, using morphological analysis of the surface and chemical composition by variable pressure scanning electron microscope (VP-SEM) and energy-dispersive x-ray (EDX) spectrometry. In addition, pore diameter and surface area were analyzed by degassing method using a porosimeter, and particle size by laser diffraction. The analyzed allograft and xenograft particles differ in morphological characteristics and chemical composition. The allograft particles present a cuboidal and prismatic geometric morphology with angled edges and the absence of macropores. On the contrary, the xenograft particles present an irregular morphology with macropores in their structure. There is a statistically significant difference in C, P, and Ca between the xenograft and allografts (p < 0,05). The analyzed composition of allografts showed mainly the presence of C and O. In contrast, the composition of the xenograft was mainly Ca. These differences could influence the osteogenic properties of allografts and xenografts. This analysis provides basic information to understand the physicochemical properties of allografts and xenografts that facilitate cell-graft interaction.

La ingeniería de tejidos tiene como objetivo fabricar un andamio que muestre una topografía de superficie adecuada para una respuesta celular deseada. Por tanto, un estudio que analice las características de los injertos óseos es importante para futuros enfoques de investigación. Este trabajo tiene como objetivo analizar las características físico-químicas de injertos óseos de origen humano y bovino disponibles comercialmente para uso odontológico, mediante análisis morfológico de la superficie y composición química mediante microscopio electrónico de barrido de presión variable (VP-SEM) y x-dispersivo de energía. espectrometría de rayos (EDX). Además, el diámetro de los poros y el área superficial se analizaron mediante el método de desgasificación utilizando un porosímetro y el tamaño de las partículas mediante difracción láser. Las partículas de aloinjerto y xenoinjerto analizadas difieren en características morfológicas y composición química. Las partículas del aloinjerto presentan una morfología geométrica cúbica y prismática con bordes angulados y ausencia de macroporos. Por el contrario, las partículas de xenoinjerto presentan una morfología irregular con macroporos en su estructura. Existe una diferencia estadísticamente significativa en C, P y Ca entre el xenoinjerto y los aloinjertos (p < 0,05). La composición analizada de los aloinjertos mostró principalmente la presencia de C y O. Por el contrario, la composición del xenoinjerto fue principalmente Ca. Estas diferencias podrían influir en las propiedades osteogénicas de los aloinjertos y xenoinjertos. Este análisis proporciona información básica para comprender las propiedades fisicoquímicas de aloinjertos y xenoinjertos que facilitan la interacción célula-injerto.

Insertion torque, flexural strength and surface alterations of stainless steel and titanium alloy orthodontic mini-implants: an in vitro study.

OBJECTIVE: This study aimed to compare the insertion torque (IT), flexural strength (FS) and surface alterations between stainless steel (SS-MIs) and titanium alloy (Ti-MIs) orthodontic mini-implants. METHODS: Twenty-four MIs (2 x 10 mm; SS-MIs, n = 12; Ti-MIs, n = 12) were inserted on artificial bone blocks of 20 lb/ft3 (20 PCF) and 40 lb/ft3 (40 PCF) density. The maximum IT was recorded using a digital torque meter. FS was evaluated at 2, 3 and 4 mm-deflection. Surface topography and chemical composition of MIs were assessed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). General linear and mixed models were used to assess the effect of the MI type, bone density and deflection on the evaluated outcomes. RESULTS: The IT of Ti-MIs was 1.1 Ncm greater than that obtained for the SS-MIs (p= 0.018). The IT for MIs inserted in 40 PCF test blocks was 5.4 Ncm greater than that for those inserted in 20 PCF test blocks (p < 0.001). SS-MIs inserted in higher density bone (40 PCF) had significantly higher flexural strength than the other groups, at 2 mm (98.7 ± 5.1 Ncm), 3 mm (112.0 ± 3.9 Ncm) and 4 mm (120.0 ± 3.4 Ncm) of deflection (p< 0.001). SEM evidenced fractures in the Ti-MIs. EDS revealed incorporation of 18% of C and 2.06% of O in the loaded SS-MIs, and 3.91% of C in the loaded Ti-MIs. CONCLUSIONS: Based on the findings of this in vitro study, it seems that SS-MIs offer sufficient stability and exhibit greater mechanical strength, compared to Ti-MIs when inserted into higher density bone.

The use of a portable X-ray fluorescence spectrometer for measuring nickel in plants: sample preparation and validation.

X-ray fluorescence is a fast, cost-effective, and eco-friendly method for elemental analyses. Portable X-ray fluorescence spectrometers (pXRF) have proven instrumental in detecting metals across diverse matrices, including plants. However, sample preparation and measurement procedures need to be standardized for each instrument. This study examined sample preparation methods and predictive capabilities for nickel (Ni) concentrations in various plants using pXRF, employing empirical calibration based on inductively coupled plasma optical emission spectroscopy (ICP-OES) Ni data. The evaluation involved 300 plant samples of 14 species with variable of Ni accumulation. Various dwell times (30, 60, 90, 120, 300 s) and sample masses (0.5, 1.0, 1.5, 2.0 g) were tested. Calibration models were developed through empirical and correction factor approaches. The results showed that the use of 1.0 g of sample (0.14 g cm-2) and a dwell time of 60 s for the study conditions were appropriate for detection by pXRF. Ni concentrations determined by ICP-OES were highly correlated (R2 = 0.94) with those measured by the pXRF instrument. Therefore, pXRF can provide reliable detection of Ni in plant samples, avoiding the digestion of samples and reducing the decision-making time in environmental management.

Analysis and 3D Imaging of Morphometric - Mineral Structure Changes in Skulls of Male and Female Guinea Pigs During and After Developmental Period

SUMMARY: Even though morphometric and mineral studies related to the guinea pig (Cavia porcellus) skull have been carried out, this study is the first attempt to evaluate all developmental stages of male and female guinea pigs. This study aims to this study is to create 3D modeling of CT images obtained from the skulls of male and female guinea pigs during the developmental period (prepuberty and the period between puberty and adulthood) and following periods (young adulthood and old adulthood), to analyze some biometric bone data such as volume, surface area and length, and to assess the developmental analysis of the mineral matter change in their skulls. The CT-scanned skulls were transferred to 3D Slicer (5.0.2), which is used for 3D modeling. The surface area and volume were calculated by measuring the measurement points on the models. In addition, the XRF device was used to show elemental ratio changes during different developmental stages. According to metric measurements, a gradual increase was observed during the life period. The metric measurements of the skull bone had a higher measurement value in male guinea pigs than in their female counterparts. While Ca/P ratio increased up to the third group and partially decreased in the fourth group in males, it gradually increased from the first group to the fourth group in females. This study revealed that puberty, adulthood and sex were effective in the physical and chemical characterization of skull bone structure in guinea pigs.

Aunque se han realizado estudios morfométricos y de minerales relacionados con el cráneo del cobayo (Cavia porcellus), esta investigación es el primer intento de evaluar las etapas de desarrollo de cobayos machos y hembras. El objetivo de este estudio fue crear un modelado 3D de imágenes de tomografía computarizada obtenidas de los cráneos de cobayos machos y hembras durante el período de desarrollo (prepubertad y el período entre la pubertad y la edad adulta) y los períodos siguientes (edad adulta joven y edad adulta mayor), para analizar algunos datos biométricos de los huesos, como el volumen, la superficie y la longitud, y además, analizar el cambio de materia mineral en sus cráneos durante el desarrollo. Los cráneos escaneados se transfirieron a 3D Slicer (5.0.2), que se utiliza para el modelado 3D. El área de superficie y el volumen se calcularon midiendo los puntos de medición en los modelos. Además, se utilizó el dispositivo XRF para mostrar los cambios en las proporciones elementales durante diferentes etapas de desarrollo. Según mediciones métricas, se observó un aumento gradual durante el período de vida. Las medidas métricas del hueso del cráneo tuvieron un valor de medición más alto en los cobayos machos que en las hembras. Mientras que la relación Ca/P aumentó hasta el tercer grupo y disminuyó parcialmente en el cuarto grupo en los machos y aumentó gradualmente del primer grupo al cuarto grupo en las hembras. Este estudio reveló que la pubertad, la edad adulta y el sexo fueron efectivos en la caracterización física y química de la estructura ósea del cráneo en cobayos.

Influence of fluoride characteristics on tooth surface protection in an erosive condition: A multifaceted characterization approach.

OBJECTIVE: To evaluate the effect of fluoride consistency and composition to protect enamel and dentin against the dental erosion. MATERIALS AND METHODS: Bovine enamel and dentin specimens were treated with artificial saliva, neutral fluoride gel (NFG), acidulated phosphate fluoride gel (AFG), neutral fluoride foam (NFF), and acidulated phosphate fluoride foam. The samples were subjected to cycling. Micro energy-dispersive X-ray fluorescence spectrometry, surface roughness (Ra), contact angle (CA), and scanning electron microscopy (SEM) were performed. Composition, CA and Ra data were analyzed by ANOVA and multiple comparison test (p < 0.05). RESULTS: The dentin protected had a significantly higher mineral content than in the control. Eroded unprotected enamel had higher Ra values than normal surfaces. Fluoride treatments increased the Ra in dentin samples. AFG increased the CA in enamel. Fluoride foams increased CA in dentin with reduced mineral loss. SEM analysis found a deposited layer on enamel treated with AFG and remnants of deposits on dentin treated with NFG and NFF. CONCLUSION: Regardless of the form of application, fluoride provided protection against erosion, however with different levels. CLINICAL SIGNIFICANCE: Applying the adequate fluoride form is relevant since the formulations have different effects on both enamel and dentin.

Measurement of elements by portable x-ray fluorescence spectrometry for the study of adsorption processes: the case of Pb2+adsorption on soybean straw biochar.

This study evaluated the reliability of portable X-ray fluorescence (pXRF) in Pb2+adsorption kinetics and isotherm experiments using soybean straw biochar. The research aimed to compare pXRF results with those obtained through traditional atomic absorption spectrometry (AAS). Soybean straw biochar, produced at 400 °C, was employed as the adsorbent for Pb2+. The efficiency of adsorption was assessed using Langmuir and Freundlich models. The kinetics of Pb2+adsorption was analysed through pseudo-first-order and pseudo-second-order models. The pseudo-second-order model described the kinetics of Pb2+adsorption on biochar better than the pseudo-first order model. Importantly, the pXRF technique demonstrated comparable results to those of AAS, making it a reliable and resource-efficient method for studying Pb2+kinetics. The results of the isotherm analyses fit the Langmuir model, indicating a desirable and irreversible adsorption of Pb2+on biochar. PXRF measurements on biochar allowed simultaneous observations of Pb2+adsorption and K+and Ca2+desorption, highlighting ionic exchange as the primary adsorption mechanism. In conclusion, our results showcased the applicability of pXRF for Pb+2adsorption studies in biochars, offering a valuable alternative to traditional methods. The findings contribute to the understanding of biochar as an effective adsorbent for heavy metals, emphasizing the potential of pXRF for cost-effective and efficient environmental research. In this study, we present a novel and detailed procedure that will allow other researchers to continue their studies on Pb2+adsorption on biochar or similar matrices, significantly reducing the resources and time used and enabling the simultaneous study of the behavior of other ions participating in the process.

On the forensic relevance of tattoos: distinguishing black inks with energy dispersive spectroscopy and backscattered scanning electron microscopy.

PURPOSE: This study aimed to analyze black tattoo inks by means of energy dispersive spectroscopy and backscattered scanning electron microscopy. METHODS: The sample consisted of five types of commercial tattoo pigments of the black colour (Easy Glow™, Electric Ink™, Iron Works™, Master Ink™, and Viper™). An Energy Dispersive Spectroscopy (EDS) detector (Silicon Drift Detector - SDD - type) attached to a Scanning Electron Microscope (SEM) device (Tescan Vega3 LMU, Libusina, Czech Republic) was used. X-ray characteristic signs were detected for each tattoo ink in an interval between 0 and 2.5 keV. The electron acceleration potential in the microscope was 15 keV. Two regions were analyzed for each sample (n = 10). On each region, a micrography of backscattered electrons (BSE) was obtained. Means and standard deviations (SD) of the weight percentages (Wt%) were calculated. RESULTS: C and O were predominant, with a mean O/C ratio between 2.69 and 2.74 Wt%. Electric Ink and Master Ink were the most similar pigments, while Easy Glow was the most distinctive - with agglomerates of Al that had a concentration 25 × higher than other specimens. Other compounds detected in the sample were Cl and Cu. CONCLUSION: EDS and SEM were efficient to distinguish black tattoo inks. These are our preliminary outcomes on the use of EDS and SEM to analyze black tattoo inks. Thus, careful interpretation is necessary to avoid rash applications in human identification practice.

Effect of incorporation of calcium polyphosphate sub-microparticles in low-concentration bleaching gels on physical properties of dental enamel.

AIM: To evaluate the bleaching efficacy and effects on enamel properties of experimental gels with carbamide peroxide (CP; 10%) or hydrogen peroxide (HP; 6%) containing calcium polyphosphate sub-microparticles (CaPPs). METHODS: A total of 216 bovine tooth specimens were divided for microhardness and color analyses (n = 108) and block randomized into nine groups (n = 12): (G1) commercial CP (Whiteness Perfect, FGM; Brazil); (G2) experimental CP; (G3) CP-0.5%CaPPs; (G4) CP-1.5%CaPPs; (G5) commercial HP (Potenza Bianco, PHS; Brazil); (G6) experimental HP; (G7) HP-0.5%CaPPs; (G8) HP-1.5%CaPPs; (G9) artificial saliva. The gels' pH values were determined with a bench pH meter. Color (ΔE, ΔE00, ΔWID) and microhardness variation were evaluated before and after the therapy. Part of the specimens used for microhardness was submitted to the scanning electron microscopy (SEM) (n = 3) and energy-dispersive X-ray spectroscopy EDX (n = 3) analyses. Statistical analyses were performed in the R statistical software (α = 0.05). Linear mixed models for repeated measures in time were used to analyze microhardness and L* values. Generalized linear models were used to analyze the a*, b*, ΔE, ΔE00, and ΔWID, considering a group effect. The EDX data were analyzed using a one-way ANOVA with Tukey's test. RESULTS: The gels' pH remained over 6,0. All gels effectively bleached the specimens and did not differ significantly. When compared to the control group, the hardness was significantly lower in the G1, G2, G6, and G7 groups. The G3, G4, G5, and G8 groups did not differ significantly (p > 0.05). CONCLUSION: The incorporation of CaPPs in low-concentration whitening gels reduces its negative effects on microhardness without interfering with their bleaching efficacy.

Chemical and morphological analysis of dentin irradiated by different high-power lasers: a systematic review.

PURPOSE: This systematic review provides an overview of the main chemical and morphological alterations generated on dentin by different high-power lasers' irradiation. METHODS: The review was registered in PROSPERO (CRD42023394164) and PRISMA guidelines were followed. The search strategy was conducted on MEDLINE (PubMed), Embase (Elsevier), and Web of Science (Clarivate) databases. The eligibility criteria were established according to the PICOS strategy, focusing on in vitro and ex vivo studies that assessed the chemical and morphological changes in dentin using five high-power lasers: Nd:YAG (1064 nm), Er:YAG (2940 nm), Er, Cr:YSGG (2780 nm), diode (980 nm), and CO2 (10,600 nm). Publication range was from 2010 to 2022. Data was summarized in tables and risk of bias was assessed by QUIN tool. RESULTS: The search resulted in 2255 matches and 57 studies composed the sample. The methods most used to assess the outcomes were scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and Raman. The studies presented "medium" and "low" risk of bias. The laser prevalently identified was the Er:YAG laser, associated with dentin ablation, absence of smear layer, and exposed tubules. The Nd:YAG laser generated vitreous surface and thermal damage, such as carbonization and cracks. The other lasers caused an irregular surface and no adverse thermal effects. Regarding the chemical structure, only the Er,Cr:YSGG laser caused collagen matrix reduction. The effects found were more intense with higher dosimetry. CONCLUSION: Evidence available indicates that the irradiation of dentin with high-power lasers are related to morphological outcomes favorable to adhesive restorative procedures, with minimal changes in collagen matrix and mineral content. However, those observations should be carried carefully by clinicians and more clinical trials regarding the association of high-power laser irradiation and restorative procedure longevity are needed.

Metals quantification in e-cigarettes liquids by Total Reflection X-ray Spectrometry.

Electronic cigarettes (e-cig) have gained popularity around the world and its health risks demands more research. This study aims at characterizing e-cig liquids (e-liquids) and its constituents by Total Reflection X-ray Spectrometry (TXRF). The internal standard method was the quantification procedure employed. The spectrometer's performance was evaluated with one certified reference material and spiked samples. It was possible to quantify K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, and Pb in the e-liquids. Concentrations above the limit for potable water were found in 10 out of 38 samples. Principal component analysis was useful for identifying toxic samples. TXRF is a promising technique for e-liquids evaluation due to its simplicity and performance.