Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.030
Filtrar
1.
Sci Total Environ ; 923: 171351, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38432370

RESUMO

Cigarette smoke contains many chemicals that are harmful to both smokers and non-smokers. Breathing just a little cigarette smoke can be harmful. There are >7000 chemicals in cigarette smoke, at least 250 are known to be harmful and many of them can cause cancer. Currently, many studies reported the types of harmful organic compounds in cigarette smoke; instead, there are almost no works that describe the presence of inorganic compounds. In this work, a cost-effective self-made passive sampler (SMPS) was tested as a tool to collect different types of particulate matter (PM) from cigarette smoke containing metals as hazardous compounds (HCs). To determine the nature of the metals, nonmetals and metalloids as HCs, a direct qualitative analysis of the particulate matter (PM) was conducted without developing any special sample preparation procedure. For that, non-invasive elemental (Scanning Electron Microscope coupled to Energy Dispersive X-ray Spectrometry) and molecular (Raman microscopy) micro-spectroscopic techniques were used. Thanks to this methodology, it was possible to determine in deposited PM, the presence of metals such as Fe, Cr, Ni, Ti, Co, Sn, Zn, Ba, Al, Cu, Zr, Ce, Bi, etc. most of them as oxides but also embedded in different clusters with sulfates, aluminosilicates, even phosphates.


Assuntos
Fumar Cigarros , Metaloides , Humanos , Metaloides/análise , Metais , Material Particulado/análise , Espectrometria por Raios X
2.
Methods Appl Fluoresc ; 12(3)2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38527374

RESUMO

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.


Assuntos
Carvão Vegetal , Soja , Chumbo , Adsorção , Reprodutibilidade dos Testes , Espectrometria por Raios X
3.
Sci Rep ; 14(1): 7243, 2024 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-38538702

RESUMO

This research explores the eco-friendly synthesis of silver nanoparticles (AgNPs) using Cassia occidentalis L. seed extract. Various analytical techniques, including UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDX), were employed for comprehensive characterization. The UV-visible spectra revealed a distinct peak at 425 nm, while the seed extract exhibited peaks at 220 and 248 nm, indicating the presence of polyphenols and phytochemicals. High-resolution TEM unveiled spherical and oval-shaped AgNPs with diameters ranging from 6.44 to 28.50 nm. The SEM exhibiting a spherical shape and a polydisperse nature, thus providing insights into the morphology of the AgNPs. EDX analysis confirmed the presence of silver atoms at 10.01% in the sample. XRD results unequivocally confirm the crystalline nature of the AgNPs suspension, thereby providing valuable insights into their structural characteristics and purity. The antioxidant properties of AgNPs, C. occidentalis seed extract, and butylated hydroxytoluene (BHT) were assessed, revealing IC50 values of 345, 500, and 434 µg/mL, respectively. Antibacterial evaluation against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli demonstrated heightened sensitivity of bacteria to AgNPs compared to AgNO3. Standard antibiotics, tetracycline, and ciprofloxacin, acting as positive controls, exhibited substantial antibacterial efficacy. The green-synthesized AgNPs displayed potent antibacterial activity, suggesting their potential as a viable alternative to conventional antibiotics for combating pathogenic bacterial infections. Furthermore, potential biomedical applications of AgNPs were thoroughly discussed.


Assuntos
Nanopartículas Metálicas , Senna (Planta) , Prata/farmacologia , Prata/química , Antioxidantes/farmacologia , Antioxidantes/química , Nanopartículas Metálicas/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Antibacterianos/química , Espectrometria por Raios X , Sementes , Difração de Raios X , Escherichia coli , Bacillus subtilis , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Biomed Phys Eng Express ; 10(3)2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38447224

RESUMO

This article describes the development of a system forin vivomeasurements of lead body burden in mice using109Cd K x-ray fluorescence (XRF). This K XRF system could facilitate early-stage studies on interventions that ameliorate or reverse organ tissue damage from lead poisoning by reducing animal numbers through a cross-sectional study approach. A novel mouse phantom was developed based on a mouse atlas and 3D-printed using PLA plastic with plaster of Paris 'bone' inserts. PLA plastic was found to be a good surrogate for soft tissue in XRF measurements and the phantoms were found to be good models of mice. As expected, lead detection limits varied with mouse size, mouse orientation, and mouse position with respect to the source and detector. The work suggests that detection limits of 10 to 20µg Pb per g bone mineral may be possible for a 2 to 3 hour XRF measurement in a single animal, an adequate limit for some pre-clinical studies. The109Cd K XRF mouse measurement system was also modeled using the Monte Carlo code MCNP. The combination of experiment and modeling found that contrary to expectation, accurate measurements of lead levels in mice required calibration using mouse-specific calibration standards due to the coherent scatter peak normalization failing when small animals are measured. MCNP modeling determined that this was because the coherent scatter signal from soft tissue, which until now has been assumed negligible, becomes significant when compared to the coherent scatter signal in bone in small animals. This may have implications for some human measurements. This work suggests that109Cd K x-ray fluorescence measurements of lead body burden are precise enough to make the system feasible for small animals if appropriately calibrated. Further work to validate the technology's measurement accuracy and performancein vivowill be required.


Assuntos
Cádmio , Chumbo , Animais , Humanos , Camundongos , Raios X , Chumbo/análise , Espectrometria por Raios X/métodos , Estudos de Viabilidade , Estudos Transversais , Impressão Tridimensional , Poliésteres
5.
Dent Mater J ; 43(2): 247-254, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38382940

RESUMO

This study investigated the potential of BioUnion filler containing glass ionomer cement (GIC) to enhance the properties of enamel surrounding restorations, with a specific focus on the effect on hardness. The hardness of the bovine enamel immersed in the cement was measured using Vickers hardness numbers. Following sliding and impact wear simulations, the enamel facets were examined using confocal-laser-scanning microscopy and scanning-electron microscopy. Surface properties were further analyzed using energy-dispersive X-ray spectroscopy and X-ray diffraction (XRD). A significant increase in Vickers hardness numbers was observed in the BioUnion filler GIC after 2 days. Furthermore, the mean depth of enamel facets treated with BioUnion filler GIC was significantly less than that of untreated facets. Characteristic XRD peaks indicating the presence of hydroxyapatite were also observed. Our findings imply that GIC with BioUnion fillers enhances the mechanical properties of the tooth surface adjacent to the cement.


Assuntos
Esmalte Dentário , Cimentos de Ionômeros de Vidro , Animais , Bovinos , Cimentos de Ionômeros de Vidro/química , Dureza , Propriedades de Superfície , Espectrometria por Raios X , Teste de Materiais
6.
Sci Total Environ ; 918: 170601, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38309346

RESUMO

Metals continue to impose health issues among world populations. A non-invasive alternative biomarker for assessment of metals and other elements has been explored in other studies using toenail samples. Some benefits of using toenails as biomarkers over blood samples include cost efficiency, ease of collection, and a longer biological half-life within samples. The objective of this study was to employ desktop XRF for the purpose of measuring metal concentrations in human nail samples, thus conducting a non-destructive assessment. These benefits paired with comparable accuracy in exposure detection could prove toenail samples to be a preferred biomarker for many studies. Current elemental quantification techniques in toenail samples could be improved. The standard practice for measuring metal exposure in toenails, inductively coupled plasma mass spectrometry (ICP-MS), has a counterpart in x-ray fluorescence. While maintaining similar quantification capabilities, x-ray fluorescence could provide decreased cost, preservation of samples, and ease of operation. Portable XRF machines have been tested for measuring toenail samples, but they have drastically increased detection limits in comparison to ICP-MS. New benchtop XRF systems should give comparable detection limits to ICP-MS. This study compares the benchtop XRF measurements of lead (Pb), copper (Cu), iron (Fe), and Selenium (Se) levels to that of ICP-MS measurements of toenail samples and calculates estimated detection limits for 23 other elements. We found strong correlations for the toenail lead (R2 = 0.92), copper (R2 = 0.95), selenium (R2 = 0.60), and iron (R2 = 0.77) comparison between desktop XRF and ICP-MS measurements. Median minimum detection limits over the 23 elements were found to be 0.2 µg/g using a 7.5-min measurement. Benchtop XRF provides a lower detection limit than previously studied portable XRF machines, which gives it the capability of accurately detecting almost any desired element in nail samples. Benchtop XRF provides a non-destructive alternative to ICP-MS in surveillance of nail samples.


Assuntos
Unhas , Selênio , Humanos , Unhas/química , Selênio/análise , Raios X , Cobre/análise , Espectrometria por Raios X/métodos , Metais/análise , Ferro/análise , Biomarcadores/análise
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 311: 124017, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38354677

RESUMO

Nanoparticles are a boon for humanity because of their improved functionality and unlimited potential applications. Considering this significance, the proposed study introduced a simple, fast and eco-friendly method for synthesis of fluorescent silver nanoparticles (Ag-NPs) using Panax Ginseng root extract as a reducing and capping agent. Synthesis of Ag-NPs was performed in one step within three minutes utilizing microwave irradiation. The resulting Ag-NPs were characterized using various microscopic and spectroscopic techniques such as, Transmission Electron Microscope (TEM), UV/Visible spectroscopy, Fourier Transform Infrared Spectroscopy(FTIR) and Energy Dispersive X-ray analysis (EDX). The prepared Ag-NPs, which act as a fluorescent nano-probe with an emission band at 416 nm after excitation at 331 nm, were used to assay nilvadipine (NLV) spectrofluorimetrically in its pharmaceutical dosage form with good sensitivity and reproducibility. The proposed study is based on the ability of NLV to quantitatively quench the native Ag-NPs fluorescence, forming a ground state complex as a result of static quenching and an inner filter mechanism. The suggested approach displayed a satisfactory linear relationship throughout a concentration range of 5.0 µM - 100.0 µM, with LOD and LOQ values of 1.18 µM and 3.57 µM, respectively. Validation of the suggested approach was examined in accordance with ICH recommendations. In addition, the anti-bacterial and anti-fungal activities of the prepared nanoparticles were investigated, and they demonstrated effective anti-microbial activities and opened a future prospective to combat future antibiotic resistance. Finally, in-vitro cytotoxicity assay of Ag-NPs against normal and cancerous human cell lines was studied using MTT assay. The results proved the potential use of the produced Ag-NPs as an adjunct to anticancer treatment or for drug delivery without significantly harming healthy human cells.


Assuntos
Antineoplásicos , Nanopartículas Metálicas , Nifedipino/análogos & derivados , Panax , Humanos , Prata/farmacologia , Prata/química , Corantes Fluorescentes/farmacologia , Nanopartículas Metálicas/química , Reprodutibilidade dos Testes , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Bactérias , Antibacterianos/química , Extratos Vegetais/farmacologia , Extratos Vegetais/química , Testes de Sensibilidade Microbiana
8.
Lasers Med Sci ; 39(1): 64, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38363355

RESUMO

The present work aimed at assessing chemical, topographical, and morphological changes induced by Nd : YAG laser treatment of dental enamels by means of energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Fifteen human enamel specimens were obtained, three of samples were kept untreated as a control while the others twelve samples were equally divided into four groups where each group have a three samples according to treating approach as: G1:(untreated);G2: (treated with Nd:YAG laser, 100 mJ/pulse,10 Hz/1064nm); G3(treated with Nd:YAG laser, 500 mJ/pulse, 10 Hz/1064nm); G4(treated with Nd:YAG laser 1000 mJ/pulse, 10 Hz/1064nm), and finally G5(treated with Nd:YAG laser, 1000 mJ/pulse, 10 Hz/532nm) respectively. Beside many craters and cracks, the AFM results showed fractures with depths of 19.23 nm, 174.7 nm, 216.9 nm, 207.4 nm and 156.5 nm and width of 559.2 nm, 833.4 nm, 1115 nm, 695.0 nm, and 5142 nm for all Groups respectively. The highest surface roughness was found in G5 with 111.4 nm while the lowest surface roughness was found in G1 to be 14.3 nm. The inside surface of the fissures was also rough. The SEM micrographs revealed modifications to the morphology. EDS was used to measure the phosphorous (P), calcium (Ca), oxygen (O), and carbon (C) percentages presented in crater areas and their surroundings, Ca, P, O, and C levels were observed to vary significantly at the crater and its rim, a lower percentage of C wt% were realized corresponding to laser treatment of 1000 mJ/Pulse laser energy. However, it was not feasible to recognize a specific chemical arrangement in the craters. It is also concluded that the higher depth and particular edge of ablated part when teeth were irradiated by laser with 1000 mJ/10Hz/1064nm.


Assuntos
Lasers de Estado Sólido , Humanos , Lasers de Estado Sólido/uso terapêutico , Cálcio/análise , Espectrometria por Raios X , Microscopia Eletrônica de Varredura , Esmalte Dentário/química
9.
Int J Paleopathol ; 44: 85-89, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38176088

RESUMO

OBJECTIVE: X-ray fluorescence (XRF) is a non-destructive technique that measures the elemental concentration of different materials, including human bone. Recently, it began to be applied to paleopathological studies due to the development of portable devices and their relative ease of use. However, the lack of uniform procedures hampers comparability and reproducibility. This paper aims to provide guidelines for an efficient and standardized evaluation of bone elemental composition with a portable XRF (pXRF) device. MATERIALS: This technical note is based on the application of the Thermo Scientific Niton XL3t 900 GOLDD+. METHODS: This work includes suggestions for the choice and preparation of human bone samples, both from archaeological context and documented collections, and methodological procedures in pXRF setup, such as choice of calibration, assessment of accuracy, and analysis run time. Additionally, recommendations for data validation and statistical analysis are also included. CONCLUSIONS: This technique has great potential in paleopathology since bone chemical variations may be associated with different pathological conditions, environmental contamination (e.g., lead), and/or administered treatments, such as mercury. Following an expected increase in the number of studies, it is essential to establish good practices that allow results from different researchers to be comparable. SIGNIFICANCE: X-ray fluorescence is a non-destructive technique that measures small concentrations (ppm) of elements from magnesium (12Mg) through bismuth (83Bi). LIMITATIONS: pXRF does not detect elements lighter than Mg, and its lower energy excitation penetrates less than other techniques. SUGGESTIONS FOR FURTHER RESEARCH: Other research groups should test these guidelines and comment on their usefulness and replicability.


Assuntos
Monitoramento Ambiental , Humanos , Raios X , Reprodutibilidade dos Testes , Espectrometria por Raios X/métodos , Monitoramento Ambiental/métodos , Radiografia
10.
Ecotoxicol Environ Saf ; 271: 115962, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38237394

RESUMO

High-precision mapping based on portable X-ray fluorescence (PXRF) data is currently being studied extensively; however, owing to poor correlation with soil metal concentration, the original PXRF data directly used for co-kriging interpolation (CKI) cannot accurately map contaminated sites with heterogeneous concentrations. Therefore, this study selected a landfill-contaminated site for research, explored the best correlation mode between PXRF variants and actual heavy metal concentration, analyzed the impact of improving the correlation model on the CKI of the spatial distribution of heavy metals, and explored the most appropriate CKI mode and point density. The results showed the following: (1) After nonlinear transformation, the correlation model between PXRF and the actual concentration was significantly improved, and the correlation coefficients of five heavy metals increased from 0.214-0.232 to 0.936-0.986. (2) The introduction of corrected PXRF data significantly improves the accuracy of CKI. Compared with the original PXRF co-kriging interpolation (OP-CKI), the ME of the corrected PXRF co-kriging interpolation (CP-CKI) for Zn, Pb, and Cu decreased by 78.2 %, 45.5 %, and 65.3 %, respectively. In terms of the spatial distribution of heavy metal pollutant concentrations, CP-CKI effectively improved the influence of local anomalous high-value points on the interpolation accuracy. (3) When the sample density measured by inductively coupled plasma mass spectrometry (ICP-MS) was less than 4 boreholes/hm2, CKI accuracy decreased significantly, indicating that the sample density should not be less than a certain threshold during CKI. (4) When the sample density measured by PXRF exceeded 7 boreholes/hm2, the mean error and root mean square error of CKI continued to decrease, suggesting that the introduction of enough sample density measured by PXRF can effectively improve the accuracy of CKI.


Assuntos
Metais Pesados , Poluentes do Solo , Raios X , Espectrometria por Raios X/métodos , Poluentes do Solo/análise , Monitoramento Ambiental/métodos , Metais Pesados/análise , Análise Espacial , Solo/química
11.
J Oral Sci ; 66(1): 50-54, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38233154

RESUMO

PURPOSE: The aim of the present study was to develop a novel method for distinguishing white spot lesions (WSLs) from sound enamel in human premolars using micro-computed tomography (micro-CT) and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and to examine differences in surface morphology, chemical composition, and mineral density (MD) between these two areas. METHODS: Fourteen premolars with natural WSLs on the enamel surface of the crowns were examined. After sectioning the teeth, each specimen containing WSLs adjacent to intact enamel was examined for MD, surface morphology, and atomic percentages (At%) of chemical components using micro-CT and SEM/EDS, respectively. Differences between these areas of the same specimen were analyzed statistically using paired t-test. RESULTS: SEM images highlighted increased roughness and irregularity in the lesion area. EDS analysis revealed significant reductions in calcium (Ca), phosphorus (P), fluorine (F), chlorine (Cl), and sodium (Na) levels at the lesion surface in comparison to intact enamel (P < 0.05). The decreases in the MD of the lesions were statistically significant in comparison to sound enamel (P < 0.05). CONCLUSION: These findings provide standard measurements for evaluating the essential characteristics of WSLs and intact enamel, being vital for assessment of treatment outcomes and development of innovative biomaterials for management of hypo-mineralized enamel lesions.


Assuntos
Cárie Dentária , Esmalte Dentário , Humanos , Microtomografia por Raio-X/métodos , Dente Pré-Molar/diagnóstico por imagem , Dente Pré-Molar/química , Dente Pré-Molar/patologia , Microscopia Eletrônica de Varredura , Esmalte Dentário/diagnóstico por imagem , Esmalte Dentário/patologia , Minerais/análise , Espectrometria por Raios X , Cárie Dentária/patologia
12.
Sci Total Environ ; 916: 170280, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38272072

RESUMO

Plastic and rubber granules are commonly used as infill material in all-weather sports facilities, providing an ideal activity surface for millions of Europeans on a daily basis. However, concerns have been raised about the presence of hazardous elements in these granules, which can pose risks both to the environment and human health. Our study focusses on the elemental composition of rubber granules used in fall sports facilities in Rzeszów, (Podkarpackie, Poland) using field portable X-ray fluorescence (FP-XRF) as a non-destructive and 'white analytical technique'. The results show the content of Zn, Fe, Cr, Ba, Br, Ti, Cu, Cd, As, Au, Bi, Pb, Ni, Sb, and Sn in the rubber granule samples. This study highlights the need for stringent quality control measures and regulations to ensure the safety of all-weather sports facilities and protect the well-being of sportsman. When modern FP-XRF spectrometry is employed as a "white analytical technique," for the first time it becomes possible to identify the presence of hazardous elements, addressing the pressing concerns highlighted by the ECHA and enabling proactive measures to mitigate potential risks. This approach ensures the protection of the health and sustainability of sports facilities, contributing to the ongoing hot topics in the field.


Assuntos
Monitoramento Ambiental , Borracha , Humanos , Monitoramento Ambiental/métodos , Polônia , Espectrometria por Raios X/métodos
13.
Anal Sci ; 40(3): 413-427, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38170424

RESUMO

The plant Saussurea Simpsoniana, which has been used in traditional medicine for its biocompatibility and abundant nutrients, offers a wide range of remedies. Local communities effectively utilize medicines derived from the plant's roots to treat various ailments such as bronchitis, rheumatic pain, and abdominal and nervous disorders. In this study, we present an elemental analysis of the chemical composition (wt%) of this medicinal plant using the laser-induced breakdown spectroscopy (LIBS) technique. In the air atmosphere, an Nd:YAG (Q-switched) laser operating at a wavelength of 532 nm is utilized to create plasma on the sample's surface. This laser has a maximum pulse energy of approximately 400 mJ and a pulse duration of 5 ns. A set of six miniature spectrometers, covering the wavelength range of 220-970 nm, was utilized to capture and record the optical emissions emitted by the plasma. The qualitative analysis of LIBS revealed the presence of 13 major and minor elements, including Al, Ba, C, Ca, Fe, H, K, Li, Mg, Na, Si, Sr, and Ti. Quantitative analysis was performed using calibration-free laser-induced breakdown spectroscopy (CF-LIBS), ensuring local thermodynamical equilibrium (LTE) and optically thin plasma condition by considering plasma excitation temperature and electron number density. In addition, a comparison was made between the results obtained from CF-LIBS and those acquired through energy-dispersive X-ray spectroscopy (EDX) analysis.


Assuntos
Plantas Medicinais , Saussurea , Lasers , Espectrometria por Raios X , Sementes
14.
PLoS One ; 19(1): e0290761, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38215075

RESUMO

The rapid, high-resolution material processing offered by ultrashort pulsed lasers enables a wide range of micro and nanomachining applications in a variety of disciplines. Complex laser processing jobs conducted on composite samples, require an awareness of the material type that is interacting with laser both for adjustment of the lasering process and for endpointing. This calls for real-time detection of the materials. Several methods such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-Ray spectroscopy (EDS) can be used for material characterization. However, these methods often need interruption of the machining process to transfer the sample to another instrument for inspection. Such interruption significantly increases the required time and effort for the machining task, acting as a prohibitive factor for many laser machining applications. Laser induced breakdown spectroscopy (LIBS) is a powerful technique that can be used for material characterization, by analyzing a signal that is generated upon the interaction of laser with matter, and thus, it can be considered as a strong candidate for developing an in-situ characterization method. In this work, we propose a method that uses LIBS in a feedback loop system for real time detection and decision making for adjustment of the lasering process on-the-fly. Further, use of LIBS for automated material segmentation, in the 3D image resulting from consecutive lasering and imaging steps, is showcased.


Assuntos
Lasers , Luz , Espectrometria por Raios X , Espectroscopia Fotoeletrônica
15.
Int J Legal Med ; 138(1): 123-137, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37227490

RESUMO

Traces from bodies can be of various nature, for example of biological or inorganic origin. Some of these historically have received more consideration than others in forensic practice. Samplings of gunshot residues or biological fluid traces are commonly standardized, whereas macroscopically invisible environmental traces are usually ignored. This paper simulated the interaction between a cadaver and a crime scene by placing skin samples on the ground of five different workplaces and inside the trunk of a car. Traces on samples were then investigated through different approaches: the naked eye, episcopic microscope, Scanning Electron Microscopy (SEM) with Energy-dispersive X-ray spectroscopy (EDX) and Energy Dispersive X-Ray Fluorescence (ED-XRF). The purpose is to provide the forensic scientist with the awareness of the value of debris on skin and then to highlight implications for forensic investigations. Results demonstrated that even naked eye observation can reveal useful trace materials, for defining the possible surrounding environment. As a next step, the episcopic microscope can increase the number of visible particulates and their analysis. In parallel, the ED-XRF spectroscopy can be useful to add a first chemical composition to the morphological data. Finally, the SEM-EDX analysis on small samples can provide the greatest morphological detail and the most complete chemical analysis, although limited, like the previous technique, to inorganic matrices. The analysis of debris on the skin, even with the difficulties due to the presence of contaminants, can provide information on the environments involved in criminal events that can add to the investigation framework.


Assuntos
Pele , Ferimentos por Arma de Fogo , Humanos , Microscopia Eletrônica de Varredura , Raios X , Espectrometria por Raios X , Pele/química
16.
Dent Mater ; 40(2): 219-226, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37977992

RESUMO

OBJECTIVES: The aim of the present work was to evaluate six commercially available abutment screws by characterising roughness parameters, microstructure and mechanical properties. METHODS: Six abutment screws from each implant system, were used. The surface roughness parameters (Sa, Sq, Ssk, Sku, Spk, Sk and Svk) were identified by an optical interferometric profiler. Microstructural observations and crystallographic analysis were performed using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray spectroscopy (EDX) device for elemental analysis and an X-ray diffractometer (XRD), respectively. The Martens Hardness (HM), Indentation Modulus (EIT), elastic index (ηIT) and Vickers hardness (HV) of all specimens were determined by instrumented indentation testing (IIT). The results were analyzed by one-way ANOVA and Tukey multiple-comparison tests (a=0.05). RESULTS: EDX and XRD showed the abutment screws to be mixed α- and ß-phase titanium alloys. Microstructural analysis revealed a fine homogeneous microstructure without porosity, consisting of fine dispersoid rods of ß-phase embedded in a continuous α-phase matrix. Statistically significant differences were found among the mechanical properies and surface roughness parameters apart from Sq, Spk and Svk. CONCLUSIONS: The tested abutment screws showed significant differences in the probed properties, and, thus, differences in their clinical behaviour are anticipated.


Assuntos
Implantes Dentários , Teste de Materiais , Dureza , Porosidade , Espectrometria por Raios X , Propriedades de Superfície , Titânio/química
17.
Luminescence ; 39(1): e4612, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37927204

RESUMO

Red and green rare-earth ion (RE3+ ) (RE = Eu, Tb):MgLa2 V2 O9 micro-powder phosphors were produced utilizing a standard solid-state chemical process. The X-ray diffraction examination performed on the phosphors showed that they were crystalline and had a monoclinic structure. The particles grouped together, as shown in the scanning electron microscopy (SEM) images. Powder phosphors were examined using a variety of spectroscopic techniques, including photoluminescence (PL), Fourier-transform infrared, and energy dispersive X-ray spectroscopy. Brilliant red emission at 615 nm (5 D0  â†’ 7 F2 ) having an excitation wavelength (λexci ) of 396 nm (7 F0  â†’ 5 L6 ) and green emission at 545 nm (5 D4  â†’ 7 F5 ) having an λexci  = 316 nm (5 D4  â†’ 7 F2 ) have both been seen in the emission spectra of Tb3+ :MgLa2 V2 O9 nano-phosphors. The emission mechanism that is raised in Eu3+ :MgLa2 V2 O9 and Tb3+ :MgLa2 V2 O9 powder phosphors has been explained in an energy level diagram.


Assuntos
Substâncias Luminescentes , Metais Terras Raras , Substâncias Luminescentes/química , Pós , Metais Terras Raras/química , Microscopia Eletrônica de Varredura , Espectrometria por Raios X
18.
Int J Biol Macromol ; 254(Pt 1): 127579, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37918606

RESUMO

Silver nanoparticles (AgNPs) by green synthesis from fungi polysaccharides are attracting increasing attention owing to their distinctive features and special applications in numerous fields. In this study, a cost-effective and environmentally friendly biosynthesizing AgNPs method with no toxic chemicals involved from the fruiting body polysaccharide of Phlebopus portentosus (PPP) was established and optimized by single factor experiment and response surface methodology. The optimum synthesis conditions of polysaccharide-AgNPs (PPP-AgNPs) were identified to be the reaction time of 140 min, reaction temperature of 94 °C, and the PPP: AgNO3 ratio of 1:11.5. Formation of PPP-AgNPs was indicated by visual detection of colour change from yellowish to yellowish brown. PPP-AgNPs were characterized by different methods and further evaluated for biological activities. That the Ultraviolet-visible (UV-Vis.) spectroscopy displayed a sharp absorption peak at 420 nm confirmed the formation of AgNPs. Fourier transform infrared (FTIR) analysis detected the presence of various functional groups. The lattice indices of (111), (200), (220), and (331), which indicated a faced-centered-cubic of the Ag crystal structure of PPP-AgNPs, was confirmed by X-ray diffraction (XRD) and the particles were found to be spherical through high resolution transmission electron microscopy (HRTEM). Energy dispersive X-ray spectroscopy (EDS) determined the presence of silver in PPP-AgNPs. The percentage relative composition of elements was determined as silver (Ag) 82.5 % and oxygen (O) 17.5 % for PPP-AgNPs, and did not exhibit any nitrogen peaks. The specific surface area of PPP-AgNPs was calculated to be 0.5750 m2/g with an average pore size of 24.33 nm by BET analysis. The zeta potential was -4.32 mV, which confirmed the stability and an average particle size of 64.5 nm was calculated through dynamic light scattering (DLS). PPP-AgNPs exhibited significant free radical scavenging activity against DPPH with an IC50 value of 0.1082 mg/mL. The MIC values of PPP-AgNPs for E. coli, S. aureus, C. albicans, C. glabrata, and C. parapsilosis are 0.05 mg/mL. The IC50 value of the inhibition of PPP-AgNPs against α-glucosidase was 11.1 µg/mL, while the IC50 values of PPP-AgNPs against HepG2 and MDA-MB-231 cell lines were calculated to be 14.36 ± 0.43 µg/mL and 40.05 ± 2.71 µg/mL, respectively. According to the evaluation, it can be concluded that these green-synthesized and eco-friendly PPP-AgNPs are helpful to improve therapeutics because of significant antioxidant, antimicrobial, antidiabetic, and anticancer properties to provide new possibilities for clinic applications.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Prata/química , Antioxidantes/farmacologia , Antioxidantes/química , Staphylococcus aureus , Hipoglicemiantes/farmacologia , Nanopartículas Metálicas/química , Escherichia coli , Extratos Vegetais/química , Anti-Infecciosos/química , Espectrometria por Raios X , Polissacarídeos/farmacologia , Antibacterianos/farmacologia
19.
J Occup Environ Hyg ; 21(2): 89-96, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38090769

RESUMO

Portable X-ray fluorescence has successfully been used to effectively evaluate occupational exposure to airborne and surface metal contaminants nondestructively. Traditional methods of assessing metal surface contamination involve the costly, time-consuming collection and laboratory analysis of wipe samples, making portable X-ray fluorescence an attractive alternative method for screening worksites by reducing delays in risk assessment decision-making. Existing research into this use of portable X-ray fluorescence has primarily been centered on the analysis of airborne and surface lead contamination. The extant literature is sparse on the use of portable X-ray fluorescence with other metals for surface contamination with respect to occupational exposure. The present study evaluated the use of portable X-ray fluorescence in the screening of cadmium surface contamination to determine if the effectiveness of decontamination measures can be ascertained by this technique. Wipe samples were collected and screened with portable X-ray fluorescence before being sent to the laboratory for definitive analysis to assess the correlation between portable X-ray fluorescence readings in percent mass with laboratory results in µg/ft2. Portable X-ray fluorescence readings demonstrated a strong linear correlation with laboratory results, as indicated by the R2 value of 0.993. Therefore, this technique may be further developed and deployed as a screening tool for wipe samples used for evaluating contamination and decontamination of metal-contaminated areas.


Assuntos
Cádmio , Monitoramento Ambiental , Monitoramento Ambiental/métodos , Raios X , Descontaminação , Espectrometria por Raios X/métodos
20.
Food Chem ; 439: 138156, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38064828

RESUMO

The paper presents a new analytical procedure for the determination and speciation of trace and ultratrace selenium in water, beverages, seafood, milk, and vegetables. The developed method is based on the dispersive micro-solid phase extraction with the use of new thiosemicarbazide-incorporated graphene as a solid sorbent, in combination of the total-reflection X-ray fluorescence spectrometry (TXRF). As a result, we have created an auspicious analytical tool for fast and sensitive analysis of samples with a complex matrix. Regardless of the specimen type, the method is characterized by a very low detection limit of 1.7 pg mL-1 and high precision. The developed strategy allowed us to solve common problems associated with selenium loss during the sample preparation for the TXRF measurement and also improve its performance toward the analysis of beverages and high saline/solid samples, which may even be impossible to perform using standard sample preparation procedures for a TXRF measurement.


Assuntos
Grafite , Selênio , Água , Selênio/análise , Grafite/química , Espectrometria por Raios X/métodos , Bebidas/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...