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1.
J Environ Sci (China) ; 145: 88-96, 2024 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38844326

RESUMO

Conventionally, soil cadmium (Cd) measurements in the laboratory are expensive and time-consuming, involving complex processes of sample preparation and chemical analysis. This study aimed to identify the feasibility of using sensor data of visible near-infrared reflectance (Vis-NIR) spectroscopy and portable X-ray fluorescence spectrometry (PXRF) to estimate regional soil Cd concentration in a time- and cost-saving manner. The sensor data of Vis-NIR and PXRF, and Cd concentrations of 128 surface soils from Yunnan Province, China, were measured. Outer-product analysis (OPA) was used for synthesizing the sensor data and Granger-Ramanathan averaging (GRA) was applied to fuse the model results. Artificial neural network (ANN) models were built using Vis-NIR data, PXRF data, and OPA data, respectively. Results showed that: (1) ANN model based on PXRF data performed better than that based on Vis-NIR data for soil Cd estimation; (2) Fusion methods of both OPA and GRA had higher predictive power (R2) = 0.89, ratios of performance to interquartile range (RPIQ) = 4.14, and lower root mean squared error (RMSE) = 0.06, in ANN model based on OPA fusion; R2 = 0.88, RMSE = 0.06, and RPIQ = 3.53 in GRA model) than those based on either Vis-NIR data or PXRF data. In conclusion, there exists a great potential for the combination of OPA fusion and ANN to estimate soil Cd concentration rapidly and accurately.


Assuntos
Cádmio , Monitoramento Ambiental , Poluentes do Solo , Solo , Espectroscopia de Luz Próxima ao Infravermelho , Cádmio/análise , Poluentes do Solo/análise , Solo/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , China , Monitoramento Ambiental/métodos , Espectrometria por Raios X/métodos , Redes Neurais de Computação , Estudos de Viabilidade
2.
Environ Monit Assess ; 196(6): 540, 2024 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-38733434

RESUMO

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.


Assuntos
Monitoramento Ambiental , Níquel , Plantas , Espectrometria por Raios X , Níquel/análise , Monitoramento Ambiental/métodos , Monitoramento Ambiental/instrumentação , Espectrometria por Raios X/métodos , Plantas/química , Poluentes do Solo/análise
3.
BMC Oral Health ; 24(1): 581, 2024 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-38764034

RESUMO

BACKGROUND: This study was conducted to compare chemical, elemental and surface properties of sound and carious dentin after application of two restorative materials resin-modified glassionomer claimed to be bioactive and glass hybrid restorative material after enzymatic chemomechanical caries removal (CMCR) agent. METHODS: Forty carious and twenty non-carious human permanent molars were used. Molars were randomly distributed into three main groups: Group 1 (negative control) - sound molars, Group 2 (positive control) - molars were left without caries removal and Group 3 (Test Group) caries excavated with enzymatic based CMCR agent. After caries excavation and restoration application, all specimens were prepared Vickers microhardness test (VHN), for elemental analysis using Energy Dispersive Xray (EDX) mapping and finally chemical analysis using Micro-Raman microscopy. RESULTS: Vickers microhardness values of dentin with the claimed bioactive GIC specimens was statistically higher than with glass hybrid GIC specimens. EDX analysis at the junction estimated: Calcium and Phosphorus of the glass hybrid GIC showed insignificantly higher mean valued than that of the bioactive GIC. Silica and Aluminum mean values at the junction were significantly higher with bioactive GIC specimens than glass hybrid GIC specimen. Micro-raman spectroscopy revealed that bioactive GIC specimens showed higher frequencies of v 1 PO 4, which indicated high level of remineralization. CONCLUSIONS: It was concluded that ion-releasing bioactive resin-based restorative material had increased the microhardness and remineralization rate of carries affected and sound dentin. In addition, enzymatic caries excavation with papain-based CMCR agent has no adverse effect on dentin substrate.


Assuntos
Cárie Dentária , Preparo da Cavidade Dentária , Dentina , Cimentos de Ionômeros de Vidro , Dureza , Humanos , Cárie Dentária/terapia , Cimentos de Ionômeros de Vidro/química , Preparo da Cavidade Dentária/métodos , Fósforo/análise , Papaína/uso terapêutico , Propriedades de Superfície , Restauração Dentária Permanente/métodos , Espectrometria por Raios X , Análise Espectral Raman , Cálcio/análise , Dente Molar , Remineralização Dentária/métodos , Alumínio , Dióxido de Silício , Teste de Materiais
4.
Astrobiology ; 24(5): 498-517, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38768431

RESUMO

Assessing the past habitability of Mars and searching for evidence of ancient life at Jezero crater via the Perseverance rover are the key objectives of NASA's Mars 2020 mission. Onboard the rover, PIXL (Planetary Instrument for X-ray Lithochemistry) is one of the best suited instruments to search for microbial biosignatures due to its ability to characterize chemical composition of fine scale textures in geological targets using a nondestructive technique. PIXL is also the first micro-X-ray fluorescence (XRF) spectrometer onboard a Mars rover. Here, we present guidelines for identifying and investigating a microbial biosignature in an aeolian environment using PIXL-analogous micro-XRF (µXRF) analyses. We collected samples from a modern wet aeolian environment at Padre Island, Texas, that contain buried microbial mats, and we analyzed them using µXRF techniques analogous to how PIXL is being operated on Mars. We show via µXRF technique and microscope images the geochemical and textural variations from the surface to ∼40 cm depth. Microbial mats are associated with heavy-mineral lags and show specific textural and geochemical characteristics that make them a distinct biosignature for this environment. Upon burial, they acquire a diffuse texture due to the expansion and contraction of gas-filled voids, and they present a geochemical signature rich in iron and titanium, which is due to the trapping of heavy minerals. We show that these intrinsic characteristics can be detected via µXRF analyses, and that they are distinct from buried abiotic facies such as cross-stratification and adhesion ripple laminations. We also designed and conducted an interactive survey using the Padre Island µXRF data to explore how different users chose to investigate a biosignature-bearing dataset via PIXL-like sampling strategies. We show that investigating biosignatures via PIXL-like analyses is heavily influenced by technical constraints (e.g., the XRF measurement characteristics) and by the variety of approaches chosen by different scientists. Lessons learned for accurately identifying and characterizing this biosignature in the context of rover-mission constraints include defining relative priorities among measurements, favoring a multidisciplinary approach to the decision-making process of XRF measurements selection, and considering abiotic results to support or discard a biosignature interpretation. Our results provide guidelines for PIXL analyses of potential biosignature on Mars.


Assuntos
Exobiologia , Meio Ambiente Extraterreno , Marte , Espectrometria por Raios X , Exobiologia/métodos , Exobiologia/instrumentação , Meio Ambiente Extraterreno/química , Espectrometria por Raios X/métodos , Espectrometria por Raios X/instrumentação
5.
Acta Odontol Scand ; 83: 264-272, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38709122

RESUMO

PURPOSE: The purpose of the present in vitro study is to investigate and compare the remineralising potential of Moringa Oleifera extract, eggshell, and sodium fluoride varnish on microhardness of artificially demineralised enamel of primary teeth with biomimetic minimally invasive approach following the world paradigm shift towards natural products in paediatric dentistry. MATERIAL AND METHODS: Sample size included 44 primary molars. The mineral content and surface microhardness of all specimens were initially assessed using energy dispersive x-ray examination (EDX) and Vickers microhardness. The specimens were artificially demineralised for 96 h at a temperature of 37°C and then reassessed directly after demineralisation. The demineralised enamel specimens were randomly divided into four groups according to the remineralisation regimen utilised. Group 1: Artificial saliva (control); Group 2: Sodium fluoride varnish; Group 3: Eggshell hydrogel; and Group 4: Moringa Oleifera hydrogel. The specimens were stored for 8 days and then subsequently evaluated using EDX and microhardness assessment by Vickers microhardness test and scanning electron microscope (SEM).  Results: Regarding the microhardness test, there was a significant difference between the Moringa Oleifera group and Eggshell group compared to fluoride varnish (p < 0.05). Regarding EDX analysis, there was a statistically significant difference (p < 0.05) between Moringa Oleifera group and Eggshell group compared to fluoride varnish as the highest values were for Moringa Oleifera and Eggshell. On the other hand, there was no statistically significant difference (p > 0.05) between Moringa Oleifera and Eggshell in both the measurements. CONCLUSION: Moringa Oleifera and Eggshell might be considered as a biomimetic natural material capable of guiding enamel tissue remineralisation in early carious lesion of primary teeth. CLINICAL RELEVANCE: This research demonstrated the capability for early enamel caries to be remineralised using novel materials with a naturally counterpart implicated in biomineralisation as proved to be more effective than traditionally used fluoride varnish in primary teeth.


Assuntos
Casca de Ovo , Hidrogéis , Moringa oleifera , Fluoreto de Sódio , Dente Decíduo , Fluoreto de Sódio/administração & dosagem , Dente Decíduo/efeitos dos fármacos , Casca de Ovo/química , Humanos , Moringa oleifera/química , Remineralização Dentária/métodos , Animais , Técnicas In Vitro , Fluoretos Tópicos/administração & dosagem , Microscopia Eletrônica de Varredura , Esmalte Dentário/efeitos dos fármacos , Dureza/efeitos dos fármacos , Espectrometria por Raios X , Desmineralização do Dente/prevenção & controle , Desmineralização do Dente/tratamento farmacológico
6.
Environ Geochem Health ; 46(6): 202, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38696051

RESUMO

Determining the origin and pathways of contaminants in the natural environment is key to informing any mitigation process. The mass magnetic susceptibility of soils allows a rapid method to measure the concentration of magnetic minerals, derived from anthropogenic activities such as mining or industrial processes, i.e., smelting metals (technogenic origin), or from the local bedrock (of geogenic origin). This is especially effective when combined with rapid geochemical analyses of soils. The use of multivariate analysis (MVA) elucidates complex multiple-component relationships between soil geochemistry and magnetic susceptibility. In the case of soil mining sites, X-ray fluorescence (XRF) spectroscopic data of soils contaminated by mine waste shows statistically significant relationships between magnetic susceptibility and some base metal species (e.g., Fe, Pb, Zn, etc.). Here, we show how qualitative and quantitative MVA methodologies can be used to assess soil contamination pathways using mass magnetic susceptibility and XRF spectra of soils near abandoned coal and W/Sn mines (NW Portugal). Principal component analysis (PCA) showed how the first two primary components (PC-1 + PC-2) explained 94% of the sample variability, grouped them according to their geochemistry and magnetic susceptibility in to geogenic and technogenic groups. Regression analyses showed a strong positive correlation (R2 > 0.95) between soil geochemistry and magnetic properties at the local scale. These parameters provided an insight into the multi-element variables that control magnetic susceptibility and indicated the possibility of efficient assessment of potentially contaminated sites through mass-specific soil magnetism.


Assuntos
Monitoramento Ambiental , Poluentes do Solo , Espectrometria por Raios X , Poluentes do Solo/análise , Espectrometria por Raios X/métodos , Análise Multivariada , Monitoramento Ambiental/métodos , Mineração , Portugal , Análise de Componente Principal , Solo/química , Estanho/análise , Fenômenos Magnéticos , Minas de Carvão , Carvão Mineral
7.
Environ Geochem Health ; 46(6): 203, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38695991

RESUMO

Manganese (Mn) is of particular concern in groundwater, as low-level chronic exposure to aqueous Mn concentrations in drinking water can result in a variety of health and neurodevelopmental effects. Much of the global population relies on drinking water sourced from karst aquifers. Thus, we seek to assess the relative risk of Mn contamination in karst by investigating the Shenandoah Valley, VA region, as it is underlain by both karst and non-karst aquifers and much of the population relies on water wells and spring water. Water and soil samples were collected throughout the Shenandoah Valley, to supplement pre-existing well water and spring data from the National Water Information System and the Virginia Household Water Quality Program, totaling 1815 wells and 119 springs. Soils were analyzed using X-ray fluorescence and Mn K-Edge X-ray absorption near-edge structure spectroscopy. Factors such as soil type, soil geochemistry, and aquifer lithology were linked with each location to determine if correlations exist with aqueous Mn concentrations. Analyzing the distribution of Mn in drinking water sources suggests that water wells and springs within karst aquifers are preferable with respect to chronic Mn exposure, with < 4.9% of wells and springs in dolostone and limestone aquifers exceeding 100 ppb Mn, while sandstone and shale aquifers have a heightened risk, with > 20% of wells exceeding 100 ppb Mn. The geochemistry of associated soils and spatial relationships to various hydrologic and geologic features indicates that water interactions with aquifer lithology and soils contribute to aqueous Mn concentrations. Relationships between aqueous Mn in spring waters and Mn in soils indicate that increasing aqueous Mn is correlated with decreasing soil Mn(IV). These results point to redox conditions exerting a dominant control on Mn in this region.


Assuntos
Água Subterrânea , Manganês , Oxirredução , Solo , Poluentes Químicos da Água , Poços de Água , Manganês/análise , Água Subterrânea/química , Poluentes Químicos da Água/análise , Solo/química , Nascentes Naturais/química , Monitoramento Ambiental , Água Potável/química , Poluentes do Solo/análise , Poluentes do Solo/química , Espectrometria por Raios X , Exposição Ambiental
8.
IEEE Trans Med Imaging ; 43(5): 1782-1791, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38696285

RESUMO

The advent of metal-based drugs and metal nanoparticles as therapeutic agents in anti-tumor treatment has motivated the advancement of X-ray fluorescence computed tomography (XFCT) techniques. An XFCT imaging modality can detect, quantify, and image the biodistribution of metal elements using the X-ray fluorescence signal emitted upon X-ray irradiation. However, the majority of XFCT imaging systems and instrumentation developed so far rely on a single or a small number of detectors. This work introduces the first full-ring benchtop X-ray fluorescence emission tomography (XFET) system equipped with 24 solid-state detectors arranged in a hexagonal geometry and a 96-pinhole compound-eye collimator. We experimentally demonstrate the system's sensitivity and its capability of multi-element detection and quantification by performing imaging studies on an animal-sized phantom. In our preliminary studies, the phantom was irradiated with a pencil beam of X-rays produced using a low-powered polychromatic X-ray source (90kVp and 60W max power). This investigation shows a significant enhancement in the detection limit of gadolinium to as low as 0.1 mg/mL concentration. The results also illustrate the unique capabilities of the XFET system to simultaneously determine the spatial distribution and accurately quantify the concentrations of multiple metal elements.


Assuntos
Imagens de Fantasmas , Animais , Espectrometria por Raios X/métodos , Desenho de Equipamento , Processamento de Imagem Assistida por Computador/métodos , Camundongos
9.
Biomolecules ; 14(5)2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38786012

RESUMO

BACKGROUND: Enamel plays an essential role in protecting the underlying layers of the human tooth; therefore, preserving it is vital. This experimental study aimed to evaluate the potential ability of L. brevis to counteract the action of a demineralizing agent on dental enamel morphology and mineral composition in vitro. METHODS: The sample consisted of 12 healthy human posterior teeth. The coronal portion of each tooth was subdivided into two equal parts longitudinally. The specimens were randomly divided into four groups: artificial saliva, L. brevis suspension, demineralizing agent (DA), and DA plus L. brevis. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to evaluate the surface micromorphology and the mineral content, respectively. The statistical analysis was conducted using a one-way ANOVA, followed by Tukey's post hoc test. RESULTS: SEM analysis did not highlight significant changes in the enamel microstructure of L. brevis-treated specimens compared to the control. DA-induced damage to the enamel structure was drastically reduced when the specimens were contextually exposed to the probiotic. The treatment with DA substantially reduced the weight % of crucial enamel minerals, i.e., Ca and P. Notably, the probiotic was able to reverse the demineralization process, bringing Ca and P weight % back to basal levels, including the Ca/P ratio. CONCLUSIONS: The findings indicate that L. brevis is able to efficiently protect the dental enamel surface from the damage caused by DA and increase the enamel resistance to demineralization. Overall, L. brevis confirms its efficacy in preventing or counteracting the action of carious lesions through a novel mechanism that protects the tooth surface under a chemical challenge that mimics the caries process.


Assuntos
Esmalte Dentário , Probióticos , Desmineralização do Dente , Humanos , Esmalte Dentário/efeitos dos fármacos , Desmineralização do Dente/prevenção & controle , Microscopia Eletrônica de Varredura , Espectrometria por Raios X , Propriedades de Superfície , Técnicas In Vitro
10.
Dental Press J Orthod ; 29(2): e2423282, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38775601

RESUMO

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.


Assuntos
Ligas Dentárias , Implantes Dentários , Resistência à Flexão , Teste de Materiais , Microscopia Eletrônica de Varredura , Procedimentos de Ancoragem Ortodôntica , Aço Inoxidável , Propriedades de Superfície , Titânio , Torque , Titânio/química , Aço Inoxidável/química , Procedimentos de Ancoragem Ortodôntica/instrumentação , Procedimentos de Ancoragem Ortodôntica/métodos , Ligas Dentárias/química , Técnicas In Vitro , Espectrometria por Raios X , Análise do Estresse Dentário , Humanos , Estresse Mecânico , Densidade Óssea
11.
Int J Prosthodont ; 37(7): 187-193, 2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38787583

RESUMO

PURPOSE: To characterize material changes that may occur in virgin cobalt-chromium (Co-Cr) alloy powder when it is blended with alloy powders that have been reused multiple times. MATERIALS AND METHODS: Initially, 20 kg of virgin Co-Cr powder was loaded into a laser-sintering device. The tensile test specimens were fabricated in the first (Group 1), fourth (Group 2), seventh (Group 3), tenth (Group 4), and thirteenth (Group 5) production cycles (N = 15). Prior to fabricating the specimens, powder alloy samples were collected from the powder bed for analysis. The tensile strength, elastic modulus, and percent elongation were calculated with tensile testing. Scanning electron microscopy and energy dispersive x-ray spectroscopy (SEM/EDS) and laser particle size distribution (LPSD) were used to analyze the alloy powder samples. The fracture surface of one tensile test specimen from each group was examined via SEM/EDS. One-way ANOVA followed by Dunnett T3 test was used for statistical analysis (α = .05). RESULTS: No difference was observed between groups in terms of tensile strength. A statistically significant difference was observed between Groups 1 and 2 in terms of percent elongation. Groups 2 and 4 were statistically significantly different in terms of both elastic modulus and percent elongation (P ≤ .05). SEM images of the powder alloy showed noticeable differences with increasing numbers of cycles. SEM images and the EDS analysis of the fractured specimens were in accordance with the strength data. CONCLUSIONS: Reusing Co-Cr alloy powder increased the particle size distribution. However, there was no correlation between increased cycle number and the mechanical properties of the powder.


Assuntos
Ligas de Cromo , Teste de Materiais , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Pós , Resistência à Tração , Ligas de Cromo/química , Módulo de Elasticidade , Espectrometria por Raios X , Técnicas In Vitro , Propriedades de Superfície
12.
BMC Res Notes ; 17(1): 128, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38711110

RESUMO

The elemental composition of chemical elements can vary between healthy and diseased tissues, providing essential insights into metabolic processes in physiological and diseased states. This study aimed to evaluate the calcium (Ca) and phosphorus (P) levels in the bones of rats with/without streptozotocin-induced diabetes and/or exposure to infrasound. X-ray fluorescence spectroscopy was used to determine the concentrations of Ca and P in Wistar rat tibiae samples.The results showed a significant decrease in bone P concentration in streptozotocin-induced diabetic rats compared to untreated animals. Similarly, the Ca/P ratio was higher in the streptozotocin-induced diabetic group. No significant differences were observed in bone Ca concentration between the studied groups or between animals exposed and not exposed to infrasound.Moreover, streptozotocin-induced diabetic rats had lower bone P concentration but unaltered bone Ca concentration compared to untreated rats. Infrasound exposure did not impact bone Ca or P levels. The reduced bone P concentration may be associated with an increased risk of bone fractures in diabetes.


Assuntos
Cálcio , Diabetes Mellitus Experimental , Fósforo , Ratos Wistar , Estreptozocina , Animais , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/induzido quimicamente , Fósforo/metabolismo , Cálcio/metabolismo , Ratos , Masculino , Espectrometria por Raios X , Tíbia/metabolismo , Som/efeitos adversos , Osso e Ossos/metabolismo , Intolerância à Glucose/metabolismo
13.
Int J Mol Sci ; 25(9)2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38731956

RESUMO

X-ray fluorescence imaging (XFI) can localize diagnostic or theranostic entities utilizing nanoparticle (NP)-based probes at high resolution in vivo, in vitro, and ex vivo. However, small-animal benchtop XFI systems demonstrating high spatial resolution (variable from sub-millimeter to millimeter range) in vivo are still limited to lighter elements (i.e., atomic number Z≤45). This study investigates the feasibility of focusing hard X-rays from solid-target tubes using ellipsoidal lens systems composed of mosaic graphite crystals with the aim of enabling high-resolution in vivo XFI applications with mid-Z (42≤Z≤64) elements. Monte Carlo simulations are performed to characterize the proposed focusing-optics concept and provide quantitative predictions of the XFI sensitivity, in silico tumor-bearing mice models loaded with palladium (Pd) and barium (Ba) NPs. Based on simulation results, the minimum detectable total mass of PdNPs per scan position is expected to be on the order of a few hundred nanograms under in vivo conform conditions. PdNP masses as low as 150 ng to 50 ng could be detectable with a resolution of 600 µm when imaging abdominal tumor lesions across a range of low-dose (0.8 µGy) to high-dose (8 µGy) exposure scenarios. The proposed focusing-optics concept presents a potential step toward realizing XFI with conventional X-ray tubes for high-resolution applications involving interesting NP formulations.


Assuntos
Grafite , Grafite/química , Animais , Camundongos , Imagem Óptica/métodos , Método de Monte Carlo , Nanopartículas/química , Paládio/química , Simulação por Computador , Espectrometria por Raios X/métodos
14.
Nutrients ; 16(9)2024 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-38732636

RESUMO

(1) Background: parenteral nutrition (PN) is indispensable for patients unable to receive oral or enteral feeding. However, the complexity of PN solutions presents challenges regarding stability and compatibility. Precipitation reactions may occur. The most frequent is the formation of calcium phosphate (Ca-P). The different factors influencing these reactions must be considered to ensure patient safety. (2) Methods: eight paediatric PN solutions were prepared, following standard protocols. Samples were stored at room temperature and in a refrigerator. Electron microscopy, coupled with energy dispersive X-ray spectroscopy (EDS), was employed. Precipitates were analysed for composition and morphology. (3) Results: precipitates were observed in all samples, even at day 0. Crystalline structures, predominantly composed of calcium or magnesium, sometimes associated with chlorine or phosphorus, were detected. Additionally, amorphous precipitates, contained heterogeneous compositions, including unexpected elements, were identified. (4) Conclusions: various precipitates, primarily calcium- or magnesium-based, can form in PN solutions, although it is not expected that they can form under the real conditions of use. Calcium oxalate precipitation has been characterised, but the use of organic calcium and phosphate salts appears to mitigate calcium phosphate precipitation. Electron microscopy provides interesting results on NP precipitation, but sample preparation may present technical limitations that affect the interpretation of the results.


Assuntos
Fosfatos de Cálcio , Precipitação Química , Estabilidade de Medicamentos , Soluções de Nutrição Parenteral , Soluções de Nutrição Parenteral/química , Fosfatos de Cálcio/química , Humanos , Nutrição Parenteral , Espectrometria por Raios X , Microscopia Eletrônica , Magnésio/química , Cálcio/química , Cálcio/análise
15.
Sci Justice ; 64(3): 305-313, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38735667

RESUMO

Heat-induced fractures can be hard to distinguish from sharp force traumas. This challenge can negatively impact medico-legal analysis. The present study aimed to experimentally assess if X-ray fluorescence (XRF) can be used to detect chemical traces transferred from the blade of a sharp instrument onto both fresh and dry human bones. This was performed by inducing sharp force traumas with five different instruments on 20 fresh and 20 dry human clavicles. All bone samples were probed before and after experimental burning (at 500 °C, 700 °C, 900 °C and 1100 °C). Our results show that XRF is potentially useful for detecting iron traces in fresh human bone, both unburned and burned. However, we were not able to clearly detect iron traces from the blades in bones that have been previously inhumed, since exogenous iron acquired during diagenesis masks the iron traces originating from the blade.


Assuntos
Temperatura Alta , Ferro , Humanos , Ferro/análise , Espectrometria por Raios X , Fraturas Ósseas , Queimaduras , Incêndios , Masculino
16.
Arch Oral Biol ; 164: 105991, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38761453

RESUMO

OBJECTIVES: To identify the genetic cause of a Chinese family with hypomaturation amelogenesis imperfecta (AI) and to characterize the structure of GPR68 mutated enamel in order to develop a deeper understanding of the role of the GPR68 protein during the intricate process of amelogenesis. DESIGN: One Chinese family with generalized hypomaturation AI was recruited. Two of the third molars from the proband were subjected to scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Whole exome sequencing (WES) was performed, and the identified mutation was confirmed by Sanger sequencing. Bioinformatics studies were further conducted to analyze the potential deleterious effects of the mutation. RESULTS: The proband presented with a hypomaturation AI phenotype, characterized by fragile and discolored enamel surface. The AI enamel showed prismatic structure, which was sporadically obscured by areas of amorphous material and porous structure. EDX analysis showed the proband's enamel demonstrated a significant decrease in calcium and phosphorus content and a significant increase in oxygen compared with normal enamel. A novel homozygous mutation of G protein-coupled receptor 68 (GPR68) (c .149 T > A, p.Ile50Asn) was identified in the proband. Bioinformatics analysis indicated that the mutation site displayed a high level of evolutionary conservation among species, and the mutation might impact the stability and conformation of the protein. CONCLUSION: The novel homozygous GPR68 mutation resulted in hypomaturation AI. We first described the effect of GPR68 mutation on enamel structure. Our results provide new genetic evidence that mutations involved in GPR68 contribute to hypomaturation AI.


Assuntos
Amelogênese Imperfeita , Esmalte Dentário , Sequenciamento do Exoma , Microscopia Eletrônica de Varredura , Mutação , Receptores Acoplados a Proteínas G , Feminino , Humanos , Masculino , Amelogênese Imperfeita/genética , China , Biologia Computacional/métodos , Linhagem , Fenótipo , Receptores Acoplados a Proteínas G/genética , Espectrometria por Raios X
17.
Biomed Phys Eng Express ; 10(3)2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38604150

RESUMO

We have previously reported the design of a portable109Cd x-ray fluorescence (XRF) system to measure iron levels in the skin of patients with either iron overload disease, such as thalassemia, or iron deficiency disease, such as anemia. In phantom studies, the system was found to have a detection limit of 1.35µg Fe per g of tissue for a dose of 1.1 mSv. However, the system must provide accurate as well as precise measurements of iron levels in the skin in order to be suitable for human studies. The accuracy of the system has been explored using several methods. First, the iron concentrations of ten pigskin samples were assessed using both the portable XRF system and ICP-MS, and the results were compared. Overall, it was found that XRF and ICP-MS reported average values for iron in skin that were comparable to within uncertainties. The mean difference between the two methodologies was not significant, 2.5 ± 4.6µg Fe per g. On this basis, the system could be considered accurate. However, ICP-MS measurements reported a wider range of values than XRF, with two individual samples having ICP-MS results that were significantly elevated (p < 0.05) compared to XRF. SynchrotronµXRF maps of iron levels in pigskin were acquired on the BioXAS beam line of the Canadian Light Source. TheµXRF maps indicated two important features in the distribution of iron in pigskin. First, there were small areas of high iron concentration in the pigskin samples, that were predominantly located in the dermis and hypodermis at depths greater than 0.5 mm. Monte Carlo modelling using the EGS 5 code determined that if these iron 'hot spots' were located towards the back of the skin at depths greater than 0.5 mm, they would not be observed by XRF, but would be measured by ICP-MS. These results support a hypothesis that iron levels in the two samples that reported significantly elevated ICP-MS results compared to XRF may have had small blood vessels at the back of the skin. Second, the synchrotronµXRF maps also showed a narrow (approximately 100µm thick) layer of elevated iron at the surface of the skin. Monte Carlo models determined that, as expected, the XRF system was most sensitive to these skin layers. However, the simulations found that the XRF system, when calibrated against homogenous water-based phantoms, was found to accurately measure average iron levels in the skin of normal pigs despite the greater sensitivity to the surface layer. The Monte Carlo results further indicated that with highly elevated skin surface iron levels, the XRF system would not provide a good estimate of average skin iron levels. The XRF estimate could, with correction factors, provide a good estimate of the iron levels in the surface layers of skin. There is limited data on iron distribution in skin, especially under conditions of disease. If iron levels are elevated at the skin surface by diseases including thalassemia and hemochromatosis, this XRF device may prove to be an accurate clinical tool. However, further data are required on skin iron distributions in healthy and iron overload disease before this system can be verified to provide accurate measurements.


Assuntos
Ferro , Pele , Espectrometria por Raios X , Ferro/análise , Pele/metabolismo , Animais , Suínos , Espectrometria por Raios X/métodos , Espectrometria por Raios X/instrumentação , Humanos , Imagens de Fantasmas , Reprodutibilidade dos Testes , Espectrometria de Massas/métodos , Cádmio/análise
18.
Metallomics ; 16(5)2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38664065

RESUMO

Mercury is a well-recognized environmental contaminant and neurotoxin, having been associated with a number of deleterious neurological conditions including neurodegenerative diseases, such as Alzheimer's disease. To investigate how mercury and other metals behave in the brain, we used synchrotron micro-X-ray fluorescence to map the distribution pattern and quantify concentrations of metals in human brain. Brain tissue was provided by the Rush Alzheimer's Disease Center and samples originated from individuals diagnosed with Alzheimer's disease and without cognitive impairment. Data were collected at the 2-ID-E beamline at the Advanced Photon Source at Argonne National Laboratory with an incident beam energy of 13 keV. Course scans were performed at low resolution to determine gross tissue features, after which smaller regions were selected to image at higher resolution. The findings revealed (1) the existence of mercury particles in the brain samples of two subjects; (2) co-localization and linear correlation of mercury and selenium in all particles; (3) co-localization of these particles with zinc structures; and (4) association with sulfur in some of these particles. These results suggest that selenium and sulfur may play protective roles against mercury in the brain, potentially binding with the metal to reduce the induced toxicity, although at different affinities. Our findings call for further studies to investigate the relationship between mercury, selenium, and sulfur, as well as the potential implications in Alzheimer's disease and related dementias.


Assuntos
Doença de Alzheimer , Encéfalo , Mercúrio , Selênio , Espectrometria por Raios X , Síncrotrons , Humanos , Mercúrio/análise , Mercúrio/metabolismo , Selênio/análise , Selênio/metabolismo , Encéfalo/metabolismo , Espectrometria por Raios X/métodos , Doença de Alzheimer/metabolismo , Idoso , Masculino , Feminino , Zinco/análise , Zinco/metabolismo
19.
Environ Pollut ; 349: 123889, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38574949

RESUMO

Cadmium (Cd) accumulation in agricultural systems has caused global environmental and health concerns. Application of phosphate fertiliser to sustain plant production unintentionally accumulated Cd in agricultural soils over time. Rapid and cost-effective Cd monitoring in these soils will help to inform Cd management practices. Compared to total Cd analysis, examining chemical fractions by sequential extraction methods can provide information on the origin, availability, and mobility of soil Cd, and to assess the potential plant Cd uptake. A total of 87 air-dried topsoil (0-15 cm) samples from pastoral farms with a history of long-term application of phosphate fertiliser were analysed using wet chemistry methods for total Cd and Cd forms in exchangeable, acid soluble, metal oxides bound, organic matter bound, and residual fractions. The data acquired using three proximal sensing techniques, visible-near-infrared (vis-NIR), mid-infrared (MIR), and portable X-ray fluorescence (pXRF) spectroscopy were used as input for partial least squares regression to develop models predicting total Cd and Cd fractions. The average total Cd concentration was 0.58 mg Cd/kg soil. For total Cd, cross-validation (cv) results of models using individual vis-NIR, MIR, and pXRF data performed with normalised root mean squared error (nRMSEcv) of 26%, 30%, and 31% and concordance correlation coefficient (CCCcv) of 0.85, 0.77, and 0.75, respectively. For exchangeable Cd, model using MIR data performed with nRMSEcv of 40% and CCCcv of 0.57. For acid soluble and organic matter bound Cd, models using vis-NIR data performed with nRMSEcv of 11% and 33% and CCCcv of 0.97 and 0.84, respectively. Reflectance spectroscopy techniques could potentially be applied as complementary tools to estimate total Cd and plant available and potentially available Cd fractions for effective implementation of Cd monitoring programmes.


Assuntos
Agricultura , Cádmio , Monitoramento Ambiental , Poluentes do Solo , Solo , Cádmio/análise , Poluentes do Solo/análise , Monitoramento Ambiental/métodos , Solo/química , Espectrometria por Raios X/métodos
20.
Microsc Microanal ; 30(2): 359-367, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38578298

RESUMO

Spatial distribution of water-soluble molecules and ions in living organisms is still challenging to assess. Energy-dispersive X-ray spectroscopy (EDS) via cryogenic scanning electron microscopy (cryo-SEM) is one of the promising methods to study them without loss of dissolved contents. High-resolution cryo-SEM-EDS has challenges in sample preparation, including cross-section exposure and sample drift/charging due to insulative surrounding water. The former becomes problematic for large and inseparable organisms, such as benthic foraminifera, a unicellular eukaryote playing significant roles in marine ecosystems, which often exceed the size limit for the most reliable high-pressure freezing. Here we show graphite oxide dispersed in sucrose solution as a good glue to freeze, expose cross-section by cryo-ultramicrotome, and analyze elemental distribution owing to the glue's high viscosity, adhesion force, and electron conductivity. To demonstrate the effectiveness and applicability of the glue for cryo-SEM-EDS, deep-sea foraminifer Uvigerina akitaensis was sampled during a cruise and plunge frozen directly on the research vessel, where the liquid nitrogen supply is limited. The microstructures were preserved as faithfully in cryo-SEM images as those with the conventional resin-substituted transmission electron micrograph. We found elements colocalized within the cytoplasm originating from water-soluble compounds that can be lost with conventional dehydrative fixation.


Assuntos
Adesivos , Microscopia Crioeletrônica , Foraminíferos , Congelamento , Espectrometria por Raios X , Foraminíferos/ultraestrutura , Microscopia Crioeletrônica/métodos , Adesivos/química , Espectrometria por Raios X/métodos , Microscopia Eletrônica de Varredura/métodos
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