Investigation of the accuracy of a portable109Cd XRF system for the measurement of iron in skin.

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.

The use of portable XRF as a forensic geoscience non-destructive trace evidence tool for environmental and criminal investigations.

Hand-held, portable X-Ray fluorescence instruments (pXRF) provide a means of rapid, in-situ chemical characterisation that has considerable application as a rapid trace evidence characterisation tool in forensic geoscience. This study presents both a control test study which demonstrates optimisation of the data collection process, alongside a range of individual forensic case studies, including heavy metal contamination, conflict archaeology, forensic soil characterisation, and verification of human remains, which together validate the technique and provide some comparison between field-based and laboratory-based pXRF applications. Results highlight the time-efficiency and cost-effectiveness of in-situ, field-based pXRF analyses for material characterisation when compared with other trace evidence methods. Analytical precision of various analytes during in-situ analysis was sufficient to demonstrate considerable application of field-based pXRF as a tool for rapid identification of specific areas of interest to be further investigated. Laboratory-based pXRF analyses yielded greater accuracy which could provide an efficient compromise between field-based pXRF and traditional laboratory-based analytical techniques (e.g. WD-XRF, ICP-MS). Further studies should collect more advanced datasets in more diverse locations to further validate the techniques capability to rapidly conduct geochemical surveys in a range of environments.

Multitechnique diagnostic analysis and 3D surveying prior to the restoration of St. Michael defeating Evil painting by Mattia Preti.

In this study, a multimethodological analysis involving optical and physical/chemical diagnostic techniques and 3D photogrammetric survey was successfully applied, for the first time, on the large oil on canvas St. Michael defeating Evil painting by Mattia Preti, located inside the Church of the Immaculate Conception of Sarria (Floriana) in Malta. Pigmenting agents, binder media, and raw materials were first characterized, both at elemental and molecular scales, through X-ray fluorescence spectroscopy (XRF), optical stereo microscopy (SM), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared spectroscopy (FT-IR), and gas chromatography coupled with mass spectrometry (GC-MS). The main goal was to properly identify the execution technique of this famous painter, the artist's palette, and possible nondocumented interventions. The 3D photogrammetric survey, on the other side, allowed us to noninvasively evaluate the extension of the areas that experienced restorations, and to properly map the domains of the different canvasses observed. The joints between canvasses suggested that the painting was folded and rolled up. In addition, the employment of a thermal camera gave evidence of the different consolidating material injection points used during the restoration to strengthen the painting. The obtained results offer useful information for the development of optimized restoration and conservation strategies to be applied and provide, at the same time, answers to open questions related to provenance and dating of the investigated artwork.

Caracterização mecânica, termodinâmica e química de fios CuNiTi ­ um estudo comparativo clínico e laboratorial / Mechanical, thermodynamic and chemical characterization of CuNiTi wires ­ a clinical and laboratory comparative study

Introdução: Os fios Copper Ni-Ti (CuNiTi) possuem indicações de uso clínico específicas, permanecendo no ambiente bucal por um longo período. Por esse motivo suas características mecânicas, termodinâmicas e estruturais devem ser preservadas durante todo o período de uso. Objetivos: Investigar se ocorrem alterações no comportamento mecânico, termodinâmico, estrutura e composição química superficial em fios CuNiTi 35°C submetidos ao envelhecimento in vivo (uso clínico) e in vitro (termociclagem), evidenciando as possíveis diferenças entre os métodos de envelhecimento. Material e Métodos: A amostra total foi constituída de 30 arcos pré-contornados 0.016", termodinâmicos com adição de cobre, e temperatura austenítica final (Af) de 35°C, da marca Ormco®. As análises destes fios resultaram em dois capítulos. Para o experimento clínico, 10 unidades de fios foram instaladas em 05 pacientes e permaneceram em meio bucal durante 30, 60 e 90 dias, e 05 fios foram analisados como recebidos (CR). A cada período, um hemiarco completo mais 1/3 (um terço) do hemiarco inferior direito foi retirado para análises. Para o experimento in vitro os 15 fios restantes foram submetidos à termociclagem para simulação do envelhecimento em ambiente oral durante 30 (600 ciclos), 60 (1200 ciclos) e 90 dias (1800 ciclos) com variação de temperatura entre 5°C e 55°C, com banhos de 90 segundos em cada temperatura, e transição de 15 segundos entre os banhos. Após cada período de envelhecimento in vivo e in vitro, os fios foram submetidos a um teste de padronização das suas dimensões através da medição dos diâmetros com paquímetro, Microscopia Eletrônica de Varredura (MEV), Espectrometria por Raios X Fluorescentes (FRX), ensaios de tração uniaxial e ensaio de Varredura Diferencial de Calorimetria (DSC). Resultados: No capítulo 1 a comparação entre os fios CR e os envelhecidos revelou que não houve diferença significativa entre os diâmetros das amostras, das forças obtidas ou mesmo das temperaturas Af, independentemente do tempo de permanência em boca. Foram encontrados predominantemente Ni, Ti, Cu e Al nas amostras, além de outros elementos químicos em concentrações variadas. No capítulo 2 não houve diferença significativa entre os diâmetros das amostras, das forças obtidas ou mesmo das temperaturas Af entre as amostras, independentemente do tempo ou do método de envelhecimento. Conclusão: As análises laboratoriais dos fios envelhecidos in vivo e in vitro foram comparadas, evidenciando que as características mecânicas, termodinâmicas e químicas dos fios permanecem estáveis mesmo até 90 dias de uso clínico ou 1800 ciclos de termociclagem. O método de envelhecimento in vitro se mostra uma alternativa viável para a análise destes parâmetros, em substituição aos métodos in vivo (AU).

Introduction: Copper Ni-Ti wires (CuNiTi) have specific indications for clinical use, remaining in the oral environment for a long period. For this reason, their mechanical, thermodynamic and structural characteristics must be preserved throughout the period of use of these materials. Objectives: To investigate whether there are changes in the mechanical, thermodynamic, structure and surface chemical composition of CuNiTi 35°C wires subjected to in vivo aging (clinical use) and in vitro (thermocycling), highlighting the possible differences between the aging methods. Material and Methods: The total sample was obtained from 30 pre-contoured Ormco® 0.016 thermodynamic archwires with copper addition and austenitic final temperature (Af) of 35°C. The analysis of these archwires resulted in two articles. For the clinical experiment, 10 units of wires were installed in 05 patients and remained in the oral environment for 30, 60 and 90 days, and 05 wires were analyzed as received. At each period, a complete hemiarch plus 1/3 of the right lower hemiarch was removed for analysis. For the in vitro experiment, the 15 remaining wires underwent thermocycling to simulate the aging of the oral environment for 30 (600 cycles), 60 (1200 cycles) and 90 days (1800 cycles) with a temperature range between 5°C and 55°C, with 90 second baths at each temperature, and 15 second transition between baths. After each in vivo and in vitro aging period, the wires underwent to a standardization test of their dimensions, by defining the diameters with a caliper, Scanning Electron Microscopy (SEM), Fluorescent X-Ray Spectrometry (FRX), tests of Uniaxial traction and Differential Scanning Calorimetry (DSC) test. Results: In chapter 1, the comparison between CR and aged wires revealed that there was no significant difference between the sample diameters, the forces obtained or even the temperatures Af, regardless the time spent in the mouth. Predominantly Ni, Ti, Cu and Al were found in the samples, in addition to other chemical elements in different concentrations. In chapter 2 there was no significant difference between the diameters of the samples, the forces obtained or even the temperatures Af between the samples, regardless of time or aging method. Conclusion: The comparison of the laboratoral analyzes of the archwires aged in vivo and in vitro showed that the mechanical, thermodynamic and the surface chemical characteristics were stable, even up to 90 days of clinical use or 1800 thermocycling cycles. The in vitro aging method is a viable alternative for the analysis of these parameters, replacing the in vivo methods (AU).

Visualising the ionome in resistant and susceptible plant-pathogen interactions.

At the morphological and anatomical levels, the ionome, or the elemental composition of an organism, is an understudied area of plant biology. In particular, the ionomic responses of plant-pathogen interactions are scarcely described, and there are no studies on immune reactions. In this study we explored two X-ray fluorescence (XRF)-based ionome visualisation methods (benchtop- and synchrotron-based micro-XRF [µXRF]), as well as the quantitative inductively coupled plasma optical emission spectroscopy (ICP-OES) method, to investigate the changes that occur in the ionome of compatible and incompatible plant-pathogen interactions. We utilised the agronomically important and comprehensively studied interaction between potato (Solanum tuberosum) and the late blight oomycete pathogen Phytophthora infestans as an example. We used one late blight-susceptible potato cultivar and two resistant transgenic plant lines (only differing from the susceptible cultivar in one or three resistance genes) both in control and P. infestans-inoculated conditions. In the lesions from the compatible interaction, we observed rearrangements of several elements, including a decrease of the mobile macronutrient potassium (K) and an increase in iron (Fe) and manganese (Mn), compared with the tissue outside the lesion. Interestingly, we observed distinctly different distribution patterns of accumulation at the site of inoculation in the resistant lines for calcium (Ca), magnesium (Mg), Mn and silicon (Si) compared to the susceptible cultivar. The results reveal different ionomes in diseased plants compared to resistant plants. Our results demonstrate a technical advance and pave the way for deeper studies of the plant-pathogen ionome in the future.

Identifying anthropogenic features at Seoke (Botswana) using pXRF: Expanding the record of southern African Stone Walled Sites.

Numerous and extensive 'Stone Walled Sites' have been identified in southern African Iron Age landscapes. Appearing from around 1200 CE, and showing considerable variability in size and form, these settlements are named after the dry-stone wall structures that characterize them. Stone Walled Sites were occupied by various Bantu-speaking agropastoral communities. In this paper we test the use of pXRF (portable X-ray fluorescence analysis) to generate a 'supplementary' archaeological record where evident stratigraphy is lacking, survey conditions may be uneven, and excavations limited, due to the overall site size. We propose herein the application of portable X-ray fluorescence analysis (pXRF) coupled with multivariate exploratory analysis and geostatistical modelling at Seoke, a southern African SWS of historical age (18th century CE). The aim of the paper is twofold: to explore the potential of the application of a low cost, quick, and minimally invasive technique to detect chemical markers in anthropogenic sediments from a Stone Walled Site, and to propose a way to analyse the results in order to improve our understanding of the use of space at non-generalized scales in such sites.

Detection of aflatoxin M1 by fiber cavity attenuated phase shift spectroscopy.

Aflatoxin M1 (AFM1) is a carcinogenic compound commonly found in milk in excess of the WHO permissible limit, especially in developing countries. Currently, state-of-the-art tests for detecting AFM1 in milk include chromatographic systems and enzyme-linked-immunosorbent assays. Although these tests provide fair accuracy and sensitivity, they require trained laboratory personnel, expensive infrastructure, and many hours to produce final results. Optical sensors leveraging spectroscopy have a tremendous potential of providing an accurate, real-time, and specialist-free AFM1 detector. Despite this, AFM1 sensing demonstrations using optical spectroscopy are still immature. Here, we demonstrate an optical sensor that employs the principle of cavity attenuated phase shift spectroscopy in optical fiber cavities for rapid AFM1 detection in aqueous solutions at 1550 nm. The sensor constitutes a cavity built by two fiber Bragg gratings. We splice a tapered fiber of < 10 µm waist inside the cavity as a sensing head. For ensuring specific binding of AFM1 in a solution, the tapered fiber is functionalized with DNA aptamers followed by validation of the conjugation via FTIR, TGA, and EDX analyses. We then detect AFM1 in a solution by measuring the phase shift between a sinusoidally modulated laser input and the sensor output at resonant frequencies of the cavity. Our results show that the sensor has the detection limit of 20 ng/L (20 ppt), which is well below both the U.S. and the European safety regulations. We anticipate that the present work will lead towards a rapid and accurate AFM1 sensor, especially for low-resource settings.

Detection and imaging of gadolinium accumulation in human bone tissue by micro- and submicro-XRF.

Gadolinium-based contrast agents (GBCAs) are frequently used in patients undergoing magnetic resonance imaging. In GBCAs gadolinium (Gd) is present in a bound chelated form. Gadolinium is a rare-earth element, which is normally not present in human body. Though the blood elimination half-life of contrast agents is about 90 minutes, recent studies demonstrated that some tissues retain gadolinium, which might further pose a health threat due to toxic effects of free gadolinium. It is known that the bone tissue can serve as a gadolinium depot, but so far only bulk measurements were performed. Here we present a summary of experiments in which for the first time we mapped gadolinium in bone biopsy from a male patient with idiopathic osteoporosis (without indication of renal impairment), who received MRI 8 months prior to biopsy. In our studies performed by means of synchrotron radiation induced micro- and submicro-X-ray fluorescence spectroscopy (SR-XRF), gadolinium was detected in human cortical bone tissue. The distribution of gadolinium displays a specific accumulation pattern. Correlation of elemental maps obtained at ANKA synchrotron with qBEI images (quantitative backscattered electron imaging) allowed assignment of Gd structures to the histological bone structures. Follow-up beamtimes at ESRF and Diamond Light Source using submicro-SR-XRF allowed resolving thin Gd structures in cortical bone, as well as correlating them with calcium and zinc.

Metals in used and unused metalworking fluids: X-ray fluorescence spectrometry as a screening test.

BACKGROUND: Exposure to metalworking fluids (MWFs) is a well-known cause of occupational contact dermatitis. OBJECTIVES: We aimed to (1) determine the amount of nickel, chromium, and cobalt in large samples of used and unused MWFs collected from metalworking plants in Denmark, and (2) evaluate a handheld x-ray fluorescence (XRF) device as a screening instrument for metals in MWFs. METHODS: A handheld XRF device was used to screen for metals in MWFs. All samples were also analyzed for concentrations of nickel, chromium, and cobalt using graphite furnace atomic absorption spectroscopy (GFAAS). RESULTS: GFAAS analysis showed that 13 of 80 samples (16.3%) contained >1 mg/kg (ppm) nickel (range: 6.4-17.7 mg/kg), 3 of 80 (3.8%) contained >1 (range: 1.4-3.1) mg/kg chromium, and 1 of 80 (1.3%) contained 1.3 mg/kg cobalt. XRF-screening detected nickel in eight samples (range: 2.5-15.5 mg/kg), but only one sample with 3.0 (±0.5) mg/kg was found subsequently to contain 9.9 (0.02) mg/kg nickel by GFAAS. Although no chromium was found by XRF analysis, cobalt was found in two samples with 6 (±1.5) mg/kg and 5 (±1.5) mg/kg, subsequently found to contain 0.1 (±0.01) mg/kg and 0.08 (±0.01) mg/kg by GFAAS. Similar concentrations of nickel were found in used (N = 6, range: 6.4-17.7 mg/kg) and unused MWFs (N = 7, range: 9.1-17.3 mg/kg). CONCLUSION: Considerable levels of nickel, chromium, and cobalt were found in some used and unused MWFs indicating that these might represent a source of metal allergy. The XRF device is a poor screening test for these metals in MWFs.

X-ray fluorescence analysis of metal distributions in cryogenic biological samples using large-acceptance-angle SDD detection and continuous scanning at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III.

A new Rococo 2 X-ray fluorescence detector was implemented into the cryogenic sample environment at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III, DESY, Hamburg, Germany. A four sensor-field cloverleaf design is optimized for the investigation of planar samples and operates in a backscattering geometry resulting in a large solid angle of up to 1.1 steradian. The detector, coupled with the Xspress 3 pulse processor, enables measurements at high count rates of up to 106 counts per second per sensor. The measured energy resolution of ∼129 eV (Mn Kα at 10000 counts s-1) is only minimally impaired at the highest count rates. The resulting high detection sensitivity allows for an accurate determination of trace element distributions such as in thin frozen hydrated biological specimens. First proof-of-principle measurements using continuous-movement 2D scans of frozen hydrated HeLa cells as a model system are reported to demonstrate the potential of the new detection system.

Preparation and characterization of naftifine-loaded poly(vinyl alcohol)/sodium alginate electrospun nanofibers

In this study, naftifine (a topical antifungal drug) loaded poly(vinyl) alcohol (PVA)/sodium alginate (SA) nanofibrous mats were prepared using the single-needle electrospinning technique. The produced nanofibers were crosslinked with glutaraldehyde (GTA) vapor. The morphology and diameter of the electrospun nanofibers were studied by scanning electron microscopy (SEM). SEM images showed the smoothness of the nanofibers and indicated that the fiber diameter increased with crosslinking and drug loading. Atomic force microscopy (AFM) images confirmed the uniform production of the scaffolds, and elemental mapping via energy dispersive X-ray spectroscopy (EDS) showed the uniform distribution of the drug within the nanofibers. An attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy study demonstrated that naftifine has sufficient secondary interactions with the polymer blend. The crosslinking treatment decreased the burst drug release effectively and the release mechanism followed Korsmeyer-Peppas Super Case-II transport. Overall, these findings suggest the potential use of naftifine-loaded PVA/SA nanofibers as a topical antifungal drug delivery system.

CALIBRATION OF A TABLETOP CONFOCAL MICROBEAM X-RAY FLUORESCENCE SPECTROMETER FOR A QUANTITATIVE DEPTH PROFILES EVALUATION.

Confocal micro-beam X-ray fluorescence analysis (confocal micro-XRF) is a non-destructive analytical tool for investigation of sample composition that enables acquiring three-dimensionally resolved information. This work describes a calibration procedure of a laboratory confocal micro-XRF setup, which leads to determination of its characteristic parameters. The calibration is performed using a tabletop confocal micro-XRF spectrometer designed recently at the Czech Technical University in Prague. The calibration procedure performed within this work comprises the essential steps of the setup characterization: excitation spectrum calculation, experimental determination of energy-dependent confocal volume size and integral sensitivity and calculation of the spectrometer sensitivity function. The results of the setup calibration will be used for development of a procedure enabling quantitative evaluation of the measured depth profiles.

Scientific instrument Femtosecond X-ray Experiments (FXE): instrumentation and baseline experimental capabilities.

The European X-ray Free-Electron Laser (EuXFEL) delivers extremely intense (>1012 photons pulse-1 and up to 27000 pulses s-1), ultrashort (<100 fs) and transversely coherent X-ray radiation, at a repetition rate of up to 4.5 MHz. Its unique X-ray beam parameters enable novel and groundbreaking experiments in ultrafast photochemistry and material sciences at the Femtosecond X-ray Experiments (FXE) scientific instrument. This paper provides an overview of the currently implemented experimental baseline instrumentation and its performance during the commissioning phase, and a preview of planned improvements. FXE's versatile instrumentation combines the simultaneous application of forward X-ray scattering and X-ray spectroscopy techniques with femtosecond time resolution. These methods will eventually permit exploitation of wide-angle X-ray scattering studies and X-ray emission spectroscopy, along with X-ray absorption spectroscopy, including resonant inelastic X-ray scattering and X-ray Raman scattering. A suite of ultrafast optical lasers throughout the UV-visible and near-IR ranges (extending up to mid-IR in the near future) with pulse length down to 15 fs, synchronized to the X-ray source, serve to initiate dynamic changes in the sample. Time-delayed hard X-ray pulses in the 5-20 keV range are used to probe the ensuing dynamic processes using the suite of X-ray probe tools. FXE is equipped with a primary monochromator, a primary and secondary single-shot spectrometer, and a timing tool to correct the residual timing jitter between laser and X-ray pulses.

Energy-dispersive Laue diffraction by means of a pnCCD detector coupled to a CsI(Tl) scintillator using ultra-hard X-ray synchrotron radiation.

The lattice parameters and unit-cell orientation of an SrLaAlO4 crystal have been determined by means of energy-dispersive X-ray Laue diffraction (EDLD) using a pnCCD detector coupled to a columnar structure CsI(Tl) scintillator in the energy range between 40 and 130 keV. By exploiting the high quantum efficiency (QE) achieved by this combined detection system for hard X-rays, a large number of Bragg reflections could be recorded by the relatively small detector area, allowing accurate and fast determination of the lattice parameters and the moduli of the structure factors. The experiment was performed on the energy-dispersive diffraction (EDDI) beamline at the BESSY II synchrotron using a pnCCD detector with 128 × 128 pixels. Since the energies and positions of the Laue peaks can be recorded simultaneously by the pnCCD system, the tetragonal structure of the investigated specimen was determined without any prior information. The unit-cell parameters and the angles between the lattice vectors were evaluated with an accuracy of better than 0.7%, while the structure-factor moduli of the reflections were determined with a mean deviation of 2.5% relative to the theoretical values.

A high-sensitivity and low dose energy-dispersive X-ray fluorescence system for identification of gadolium accumulations in planar X-ray fluorescence images.

A new technique, based on in-vivo energy dispersive X-ray fluorescence (EDXRF), has been developed to gadolinium (Gd) concentrations identification in planar X-ray fluorescence (XRF) images. Higher signal-to-noise (SNR) ratios while keeping a low radiation dose were achieved. Experimental validation was performed using tissue equivalent phantoms under two different data acquisition criteria. The first criteria consisted on acquiring the energy spectra from different experimental narrow spectrum beam (FWHM = 2.5 keV) with peak central energy above the L edge energy and determining the spectrum which producing Lowest-Limit-of-Detection (Lowest-LoD) for a specific acquisition time. This also provided the minimum dose expected under the condition of minimum irradiation time. The second criteria consisted on measuring the surface dose required to obtain a specific LoD by different narrow spectrum beam, providing the Lowest-Dose setting. Surface (2D) Gd-doped tissue-equivalent phantoms scanning were performed according to optimized scenarios: Lowest-LoD setting (obtaining to central energy of 10.9 keV) and Lowest-Dose setting (obtaining to central energy 12.9 keV). 625 pixel images were acquired in two different conditions: a pre-defined time (5 s) per pixel was set in the first approach, whereas a pre-defined total surface dose (4 mGy) was set to the second approach. According to the results obtained for the first approach, a 58 times reduction was observed when comparing SNR between the Lowest-LoD and Lowest-Dose settings. On the other hand, for the second approach pre-defining total dose during the whole examination, the best SNR was obtained for the Lowest-Dose configuration exhibiting a 42% of increment respecting to the Lowest-LoD configuration and 47 times higher when compared with the limit case of no optimization.

Large-scale micron-order 3D surface correlative chemical imaging of ancient Roman concrete.

There has been significant progress in recent years aimed at the development of new analytical techniques for investigating structure-function relationships in hierarchically ordered materials. Inspired by these technological advances and the potential for applying these approaches to the study of construction materials from antiquity, we present a new set of high throughput characterization tools for investigating ancient Roman concrete, which like many ancient construction materials, exhibits compositional heterogeneity and structural complexity across multiple length scales. The detailed characterization of ancient Roman concrete at each of these scales is important for understanding its mechanics, resilience, degradation pathways, and for making informed decisions regarding its preservation. In this multi-scale characterization investigation of ancient Roman concrete samples collected from the ancient city of Privernum (Priverno, Italy), cm-scale maps with micron-scale features were collected using multi-detector energy dispersive spectroscopy (EDS) and confocal Raman microscopy on both polished cross-sections and topographically complex fracture surfaces to extract both bulk and surface information. Raman spectroscopy was used for chemical profiling and phase characterization, and data collected using EDS was used to construct ternary diagrams to supplement our understanding of the different phases. We also present a methodology for correlating data collected using different techniques on the same sample at different orientations, which shows remarkable potential in using complementary characterization approaches in the study of heterogeneous materials with complex surface topographies.

Assessing zinc from a nail clipping using mono-energetic portable X-ray fluorescence.

A mono-energetic X-ray beam from a portable X-ray fluorescence device was used to excite characteristic X-rays from zinc in a series of nail clipping phantoms. Twenty nail clipping phantoms having equal zinc concentrations of ~40 µg/g, but with different physical characteristics, were measured individually for 300 s using a small diameter (~1 mm) X-ray beam. Energy spectra obtained from the measurements were analyzed using PyMca software. Zinc signal size varied widely between the different clippings, with a relative standard deviation of 41% observed in the combined signal from zinc Kα and Kß characteristic X-rays. Three different normalization approaches were introduced to account for variation in the amounts of sample interrogated by the X-ray beam. All three approaches produced similar results, and successfully reduced the relative standard deviation to between 12% and 13%. A clear trend was still observed, however, between the normalized zinc signal and the thickness of clipping measured. To account for this effect, normalized signals were adjusted to calculate "thickness-corrected" values. The relative standard deviation of these thickness-corrected values was 6.2%. Reproducibility of measurement from individual clippings was excellent, with relative standard deviations on the order of 1%, with or without normalization. Overall, this new method of measuring zinc in nail shows promise for the assessment of zinc status in humans using a portable device. The method is sensitive, rapid, and requires only a single nail clipping.

Surface Structures of Cosmetic Standard Poly Methyl Methacrylate UV Evaluation Plates and their Influence on the in vitro Evaluation of UV Protection Abilities of Cosmetic Sunscreens.

Cosmetic standard poly methyl methacrylate (PMMA) UV evaluation plates, i.e., roughened PMMA plates, are used in the EU and the US for the in vitro evaluation of UV protection abilities of sunscreen, such as in vitro UVA-PF and critical wavelength for the Broad-spectrum approval. In our previous studies, inhomogeneity in the thickness of a pseudo-sunscreen layer applied on a flat quartz plate was observed to alter UV transmission. Thus, the surface roughness of the standard plates should have a significant influence on the in vitro evaluation. In the present study, we have analyzed the surface structures of three cosmetic standard PMMA UV evaluation plates: Helioplates HD6 (Sa = 6 µm) and ISO plates (Ra = 2 and 5 µm). A decamethylcyclopentasiloxane and 2-propanol-mixed solvent solution of acrylsilicone resin was prepared, and the solution was added dropwise onto the plates. After the evaporation of the solvents, the plates were cut and the cross section was analyzed using SEM-EDS. The distribution of silicon atoms at the cross-section suggested that the maximum depth of penetrating of acrylsilicone resin was larger than Ra for all the standard plates, and the surface structure was significantly different for each standard plate. In addition, cracks into which the acrylsilicone resin deeply penetrated were observed on the surface of some plates. Clear-solution-type pseudo-sunscreen samples in which UV absorbers and acrylsilicone resin were dissolved were deposited on the standard roughened PMMA plates. It was observed that the addition of acrylsilicone resin drastically changed the net UV transmission. The degree to which the hollows of the roughened surface were filled with the pseudo-sunscreen samples determined the variation of UV transmittance.

Biogeochemical mapping of metal contamination from mine tailings using field-portable XRF.

Trace and major element composition of selected plant species and parts may be used to map geochemical dispersion from mineral deposits and contaminated areas. This study examines the application of field-portable X-ray fluorescence spectrometry (fpXRF) in obtaining real-time biogeochemical data. In situ analysis of parts of black and silver wattle (Acacia mearnsii De Wild. and Acacia dealbata Link) was conducted to map the extent of contamination surrounding the former Woodlawn base metal mine. High levels of ore-related elements were detected in the bark of these species in a zone extending up to 1 km down-drainage from the tailing ponds. Major elements are more elevated in bark on the side of the trees facing the tailings ponds and correlations between trace and major elements indicate dust contamination. The penetration distance for X-rays is dependent on the energy of the secondary X-rays measured, with the maximum depth of penetration in bark and leaf material <30 mm. There was a close correlation for most elements between the fpXRF and laboratory-based XRF analysis but with element-dependent attenuation by the organic matrix. Providing there is consistency in sampling and analytical methodology, in situ fpXRF analysis of vegetation is an effective method in both contamination surveys and biogeochemical mineral exploration for a range of trace and major elements.

Application of Electron Microscopes in Nanotoxicity Assessment.

In this chapter, we highlight the applications of electron microscopes (EMs) in nanotoxicity assessment. EMs can provide detailed information about the size and morphology of nanomaterials (NMs), their localization in cells and tissues, the nano-bio interactions, as well as the ultrastructural changes induced by NMs exposure. Here, we share with the readers how we prepare the tissue sample, and the different types of EMs used among the nanotoxicologists. It is possible to deploy conventional EMs along or in combination with other analytical techniques, such as electron energy loss spectroscopy (EELS), energy dispersive X-ray spectroscopy (EDS or EDX), and TEM-assisted scanning transmission X-ray microscopy (STXM), toward further elemental and chemical characterization. Appropriate images are inserted to illustrate throughout this chapter.