Particle Induced X-ray Emission Analysis Research Articles

PIXE analysis of Late Bronze Age situlae from the eponymous Hajdúböszörmény-Csege-halom I hoard and Sényő-Dajkahegy, Northeastern Hungary

The paper introduces the particle-induced X-ray emission analysis (PIXE) of two Hajdúböszörmény-type situlae from the eponymous Hajdúböszörmény I hoard (collection of the Hungarian National Museum, Budapest) and Sényő (collection of the Jósa András Museum, Nyíregyháza). Both situlae are representative types of the period between 1080 and 960 BC, Ha B1, or the ‘Hajdúböszörmény hoard horizon’ of the Hungarian Late Bronze Age. The obtained results are significant in that they are the very first to characterise the classic Hajdúböszörmény-type situla from their core distribution area, i.e., the region where this metal vessel type was presumably produced. The paper is focused on a description of the elemental composition of these tin bronze vessels, with particular attention on the grouping of their accompanying elements and the ratio of tin. The PIXE results suggest that a rather homogenous raw material was used to produce and repair these objects, which can be correlated with the CG16 Copper Group. The ratio of tin was relatively high, mostly around 9–10 wt%; low values were only identified on one of the repaired parts of the Sényő situla and a secondarily attached copper rivet.

Application of non-destructive analysis methods in TENMAK-PAF

Development of non-destructive analysis systems at the R&D beamline of the Proton Accelerator Facility of the Turkish Energy, Nuclear and Minerals Research Agency (TENMAK-PAF) is described in this work. The proton beam from the cyclotron with energy between 15–30 MeV and current between 0.1 μA–1.2 mA is modified with several components and subsystems to be suitable for the application of non-destructive analysis methods. Certified reference materials (CRM) and samples with different properties were irradiated under vacuum in the irradiation chamber with the new system. Particle Induced X-ray Emission (PIXE) and Particle Induced Gamma ray Emission (PIGE) spectra of these samples were obtained with appropriate radiation detectors and measurement systems. The results of PIXE analyses and X-ray fluorescence (XRF) spectrometry were compared. PIXE and PIGE results are in good agreement with the certified values for the CRMs. This work constitutes the first reported application of non-destructive ion beam analysis methods in TENMAK-PAF and in Türkiye.

Helium and Proton Particle-Induced X-Ray Emission (PIXE) for Characterization of PM2.5 from Surabaya, Indonesia

Generally, particle-induced X-ray emission (PIXE) analysis is performed using protons as the incident projectiles. In this study, helium ions were used for inducing X-ray emission to improve the detection limit for the characterization of light elements in the PM2.5 fine fraction. The sampling was conducted for 24 h using a Gent stacked filter unit sampler at an industrial site in Surabaya, Indonesia. The samples were analyzed by PIXE using a 4-MV Van de Graaff accelerator at Kyoto University. Both helium and protons were used in the analysis to obtain optimal results, and 21 elements were detected in the samples. Notably, the use of helium particle-induced X-ray emission was more suitable for Na, Mg, Al, and Si than protons. Moreover, the sensitivity and limit of detection for these elements were enhanced using helium ions. Validation was performed using standard reference material NIST 2783 air particulates on filter media, and the results were in good agreement. Using both He-PIXE and H-PIXE, heavy metals, crustal elements, and other elements were identified that exhibited the characteristics of PM2.5 collected in Surabaya, Indonesia. Further statistical analysis and receptor modeling are required to identify the possible pollutant sources of PM2.5.

Plant Growth-Promoting Rhizobacteria (PGPR) Reduce Adverse Effects of Salinity and Drought Stresses by Regulating Nutritional Profile of Barley

With the growing emphasis on sustainable agriculture, food security, and environmental protection, the use of beneficial soil microbes is imperative, as the use of chemicals such as fertilizers, pesticides, and herbicides has resulted in food contamination, disease, weed resistance, and negative environmental consequences, which ultimately impacted human health. Climate change is a major factor and is of great concern for crop production. Abiotic stresses, including salt and drought stress, restrain the crop yield. The aim of this particular study is to understand what role do plant growth-promoting rhizobacteria (PGPR) play in combating the salinity and drought stresses through modification of nutritional profile. In the current study, inoculated barley (Hordeum vulgare L.) plants were subjected to various stresses such as 200 mM and 1000 mM salinity stress as well as drought stress, and then their various parameters such as seed germination as well as shoot and root biomasses and photosynthetic activity were compared with non-treated stressed barley plants. Our data depicted an improvement or significant enhancement of these parameters in PGPR (Pseudomonas fluorescens SBW25 and Pseudomonas putida KT2440) applied barley plants. Furthermore, the particle-induced X-ray emission (PIXE) technique was used for the elemental analysis of PGPR-inoculated and non-inoculated plants under stress vs. no stress conditions. Our PIXE analysis of various macro- and micronutrients revealed an enhancement of Ca, Mg, K, P, S, Al, and Si uptake in PGPR-treated plants. PGPR applications depicted reduced Cl− contents in 200 mM salt-stressed barley roots (KT2440 = 7.7 mg/kg and SBW25 = 6.3 mg/kg) and stems (KT2440 = 406.4 mg/kg and SBW25 = 365.5 mg/kg) as compared to controls (roots = 8.9 and stems = 469.5), while they displayed a significant increase in the barley leaves (KT2440 = 405 mg/kg and SBW25 = 416.4 mg/kg) when compared to control (110.6 mg/kg) under the same stress condition. In 1000 mM salt stress, a significant reduction in the Cl− content was observed in PGPR-applied barley roots (KT2440 = 7.6 mg/kg), stems (KT2440 = 1205.8 mg/kg and SBW25 = 1008.3 mg/kg), and leaves (KT2440 = 967.8 mg/kg and SBW25 = 530.8 mg/kg) when compared to controls (roots = 15.2 mg/kg, stems = 1605.2 mg/kg, and leaves = 1165.2 mg/kg). On the other hand, a significant increase in the Cl− content was noticed in PGPR-applied barley roots (KT2440 = 29.5 mg/kg and SBW25 = 25.8 mg/kg), stems (KT2440 = 1023.8 mg/kg and SBW25 = 894.9 mg/kg), and leaves (KT2440 = 369.2 mg/kg and SBW25 = 409.8 mg/kg) when compared to controls (roots = 13.5 mg/kg, stems = 505.3 mg/kg, and leaves = 219.9 mg/kg) under drought stress condition. PGPR application was also found to be effective for enhancing the uptake of micronutrients (Mn, Fe, Co, Ni, Cu, and Zn) in barley plant parts under control and also under stressed conditions. Overall, our findings revealed an improvement in the uptake of macro- and micronutrients for the enhancement of salinity and drought stress tolerance. Conclusively, these PGPR species are an effective source of plant stress tolerance and elevated growth of barley and related plants under stress conditions.

Evaluation of the remaining spent extraction solvent in vermiculite after leaching tests via PIXE analysis

The spent extraction solvent, primarily comprising tributyl phosphate (TBP) and normal dodecane, is waste product generated by the solvent extraction of plutonium and uranium to develop the plutonium–uranium redox-extraction process. The spent solvent should be appropriately treated for disposal or storage. One treatment option for storing the spent solvent is the adsorption of the liquid into vermiculite. The organic liquid is trapped between the vermiculite layers. Our previous experiments on the adsorption of spent solvent into vermiculite have shown that some parts of the loaded solvent gradually leaked from the vermiculite. Therefore, the elution behavior of the loaded solvent into organic diluents, such as hexane or acetone, were evaluated to investigate the adsorption mechanism and capacity. Some loaded solvents easily leaked into the diluent, whereas some remained inside the particle, even after the leaching test. The difference in behavior might be attributed to different adsorption mechanisms, and the amount of the remaining solvent is the adsorption capacity for safely storing the solvent. This study evaluated the vermiculite adsorption capacity via the remaining solvent after washing with diluents, such as ethanol or distilled water. The remaining solvent was analyzed using particle-induced X-ray emission (PIXE) on phosphorous (P) contained in the TBP. PIXE analysis quantitatively analyzed the trace amounts of residual TBP, and n-dodecane and TBP were suggested to be adsorbed to vermiculite by different mechanisms.

Towards compact laser-driven accelerators: exploring the potential of advanced double-layer targets

The interest in compact, cost-effective, and versatile accelerators is increasing for many applications of great societal relevance, ranging from nuclear medicine to agriculture, pollution control, and cultural heritage conservation. For instance, Particle Induced X-ray Emission (PIXE) is a non-destructive material characterization technique applied to environmental analysis that requires MeV-energy ions. In this context, superintense laser-driven ion sources represent a promising alternative to conventional accelerators. In particular, the optimization of the laser-target coupling by acting on target properties results in an enhancement of ion current and energy with reduced requirements on the laser system. Among the advanced target concepts that have been explored, one appealing option is given by double-layer targets (DLTs), where a very low-density layer, which acts as an enhanced laser absorber, is grown to a thin solid foil. Here we present some of the most recent results concerning the production with deposition techniques of advanced DLTs for laser-driven particle acceleration. We assess the potential of these targets for laser-driven ion acceleration with particle-in-cell simulations, as well as their application to PIXE analysis of aerosol samples with Monte Carlo simulations. Our investigation reports that MeV protons, accelerated with a ∼20 TW compact laser and optimized DLTs, can allow performing PIXE with comparable performances to conventional sources. We conclude that compact DLT-based laser-driven accelerators can be relevant for environmental monitoring.

126 Emission and Exposure Characterization During Metal Waste Recycling

Abstract Waste of electrical and electronic equipment (WEEE) is one of the fastest-growing waste streams in the EU. The airborne occupational and environmental exposures generated by this waste handling are poorly quantified, and the growing use of nanomaterials in electronics adds to the uncertainty of risk assessment. Emission and personal exposure measurements were carried out during industrial recycling for three different metal waste flows: WEEE, metal scrap and cables. Size distributions and number-, mass- and lung deposited surface area concentrations were assessed by on-line techniques, and filter samples were collected for gravimetric analyses, metal content, and electron microscopy. Samples for elemental analyses with Particle Induced X-ray Emission (PIXE) was collected by a 12-stage low-pressure impactor . Additionally, low-cost sensors were deployed for long term monitoring. By number, the size distributions from all three flows were heavily dominated by particles <100 nm. Electron microscopy showed that there are many different elements in the same particle and that the composition of different particles vary considerably. Abundant elements, according to ICP-MS, were Fe, Al, Zn, and Cu, but Pb, Mn, Ba, and Co were also detected. PIXE analysis showed that the chemical composition indeed is different in different particle sizes, with e.g. Cr almost exclusively being present in particles < 200 nm. Low-cost sensors, not previously used for monitoring in highly polluted industrial settings, functioned well after 30 days. This study shows that detailed particle characterization is crucial for understanding of today’s and tomorrow’s waste recycling exposures, and as input to future toxicological assessments.

Toxicological potential of Aloysia gratissima: Insights from chemical analysis and in vitro studies

Ethnopharmacological relevanceAloysia gratissima leaves are popularly used to treat respiratory, digestive, and nervous system disorders. Several studies have been carried out to determine the biological activity of A. gratissima, such as its antibacterial and anti-edematogenic activities, but despite the beneficial uses of A. gratissima, few studies have examined the toxicological profile of this plant.Aim of the study: This study aimed to determine the chemical composition, cytotoxic, genotoxic, mutagenic potential, and antioxidant activity of an aqueous extract of A. gratissima leaves (AG-AEL). Material and methodsThe phytochemical constitution of AG-AEL was assessed by colorimetric analyses and High-performance liquid chromatography (HPLC). The inorganic elements were detected by Particle-Induced X-ray Emission (PIXE). The antioxidant, cytotoxicity, genotoxic, and mutagenic activities were evaluated in vitro by Di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH), Sulforhodamine B (SRB) assay, comet assay, and Salmonella/microsome assays. ResultsAG-AEL indicated the presence of terpenoids, flavonoids, and phenolic acids. HPLC detected rutin at 2.41 ± 0.33 mg/100 mg. PIXE analysis indicated the presence of Mg, Si, P, S, K, Ca, Mn, and Zn. The 50% inhibitory concentration was 84.17 ± 3.17 μg/mL in the DPPH assay. Genotoxic effects were observed using the Comet assay in neuroblastoma (SH-SY5Y) cells and mutations were observed in TA102 and TA97a strains. The extract showed cytotoxic activities against ovarian (OVCAR-3), glioblastoma (U87MG), and colon (HT-29) cancer cell lines. ConclusionsIn conclusion, AG-AEL increased DNA damage, induced frameshift, and oxidative mutations, and showed cytotoxic activities against different cancer cells. The in vitro toxicological effects observed suggest that this plant preparation should be used with caution, despite its pharmacological potential.

Electrostatic accelerator facilities and their applications at Peking University

<p indent="0mm">Electrostatic accelerators are powerful tools in many research fields, such as nuclear physics, materials science, and archaeology. Three electrostatic accelerators, the 1.7 MV tandem, the single stage Van de Graaff with a terminal voltage of 4.5 MV, and the EN tandem with a terminal voltage of 6 MV, were installed in 1980s and have been put into operation since the early 1990s at Peking University. The 1.7 MV tandem accelerator is equipped with a radio frequency charge exchange negative ion source and a cesium sputtering negative ion source, which can produce most of the ions from H to Au. It accelerates the ions to energies from several hundreds of keV to several MeV. The accelerator is used for ion irradiation, ion beam modification of materials, as well as ion beam analysis (IBA), such as Rutherford backscattering spectroscopy (RBS) and channeling. Many significant achievements have been made by using the ion irradiation beamline, especially in the research of nuclear materials. The superlattice steel containing a high density of B2-ordered Ni(Al, Fe) superlattice nanoprecipitates (NPs) was irradiated with <sc>6 MeV</sc> Au ions at different high temperatures. The superlattice steel exhibits extraordinary radiation tolerance, namely, zero void swelling at 400–600°C under an average radiation damage of up to <sc>2350 dpa,</sc> outperforming most of the other steels studied to date. This paper demonstrates a counterintuitive strategy to enhance the radiation resistance of metallic materials by simply ordered superlattice NPs. For the 4.5 MV electrostatic accelerator, the isotope ions of hydrogen or helium can be produced in the energy range of <sc>0.7–3.8 MeV,</sc> and continuous or pulsed quasi-monoenergetic neutron fields <sc>(0.03–7 MeV,</sc> <sc>14–19 MeV)</sc> can be generated by ion beam bombarding targets. The neutron fields have applied it to measure (n, α) reaction cross section. Based on the 4.5 MV electrostatic accelerator, a total-IBA system has been established. Total-IBA can obtain self-consistency results through analyzing spectra of different emission particles, without massive modification of equipment. RBS-nuclear reaction analysis (NRA)-particle-induced X-ray emission analysis (PIXE) integrated IBA experiment was carried out to study a Fe-based alloy. The incident particle is ³He⁺ under <sc>3.0 MeV.</sc> The integrated charge is obtained by fitting the RBS spectrum. The content and depth distribution of C element can be determined by analyzing the NRA spectrum. The signal of O element can also be observed in the NRA spectrum, and its depth distribution can be obtained by fitting RBS. More than ten trace elements are analyzed by PIXE, and P has the lowest content, which is <sc>158.2 ppm.</sc> The 6 MV EN tandem accelerator, which has supported much basic and application research at Peking University, was transferred from Oxford University, UK. It is suitable for accelerator mass spectrometry (AMS), ion irradiation and ion beam analysis. The accelerator can also be applied for detector calibration. CR-39 nuclear track detectors were irradiated by <sc>3–8 MeV</sc> mono-energetic protons and <sc>6–30 MeV</sc> mono-energetic carbon ions, which were produced by the 6 MV tandem accelerator. The relationships between particle energy and orbital diameter in CR-39 detectors are established. These data on CR-39 detectors will be useful for identifying reaction products in laser-plasma experiments with complex conditions. With the technique development such as modern ion beam analysis technology and multi-beam to one target, more attractive applications are expected.

Characterization of agricultural biomass by particle induced x-ray emission and Rutherford backscattering techniques

Particle-induced x-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) techniques are non-destructive elemental analyses method with high sensitivity and capability for multi-element analysis in one spectrum. These techniques have not been used for the elemental characterization of biomass. So, this study characterized and evaluated elemental compositions of some selected agricultural biomass (Palm kernel shell (PKS), coconut shell (CS), cassava peel (CP), and Africa star apple seed shell (ASASS)) using combined PIXE and RBS. The results were compared with the ultimate analysis and optical-based techniques. Results from PIXE and RBS analysis confirm the presence of C, O, S, Na, Mg, P, Si, K, Ca, Fe, Cl, Al, Ti, Cu, and Zn in the tested biomass samples. Estimation of RBS accuracy by direct comparison with the ultimate analysis of some biomass samples showed a wide disparity of ±10.7% and ±2.57% in the RBS data for carbon and oxygen in PKS and a disparity of ±5.22% and ±0.55% in the RBS data for carbon and oxygen in coconut shell respectively. In the case of minor and trace element concentrations, estimated errors in the range of 1–3% and 2.68–4% were observed for optically based techniques compared with PIXE and RBS analysis, respectively.

Trace Elements in Tears: Comparison of Rural and Urban Populations Using Particle Induced X-ray Emission.

We aimed to evaluate the types and concentrations of trace elements in tears of individuals living in urban and rural environments using particle induced X-ray emission (PIXE) and the possible association with exposure to air pollution and suggest a novel method for tear-based biomonitoring studies. This cross-sectional pilot study comprised 42 healthy subjects, 28 living in a rural area and 14 in an industrial city. Tears were collected with Schirmer paper and characterized by PIXE. Trace element concentrations from both eyes were averaged together with environmental pollution data. Main outcome measures were between-group differences in types and concentrations of trace elements in tears and comparison to environmental data. The rural group included 12/28 men, mean age 45.2 ± 14.8 years. The urban group consisted of 11/14 men of mean age 27 ± 5.9 years. Six rural and all urban were active smokers. Air pollution data showed more toxic elements in the rural environment. On PIXE analysis, chlorine, sodium, and potassium were found in similar concentrations in all samples. Normalizing to chlorine yielded higher values of aluminum, iron, copper, and titanium in the rural group; aluminum was found only in the rural group. The higher levels of certain trace elements in the rural group may, in part, be a consequence of exposure to specific environmental conditions. No direct association was found with air pollution data. PIXE is useful to analyze trace elements in tears, which might serve as a marker for individual exposure to environmental pollutants in biomonitoring studies.

Magnetic and elemental characterization of the particulate matter deposited on leaves of urban trees in Santiago, Chile

Airborne particulate matter is a serious threat to human health, especially in fast-growing cities. In this study, we carried out a magnetic and elemental study on tree leaves used as passive captors and urban dust from various sites in the city of Santiago, Chile, to assess the reliability of magnetic and elemental measurements to characterize particulate matter pollution from vehicular origin. We found that the magnetic susceptibility and saturation isothermal remanent magnetization measured on urban tree leaves is a good proxy for tracing anthropogenic metallic particles and allow controlling the exposure time for particulate matter collection, in agreement with other studies carried out in large cities. Similar measurements on urban soil can be influenced by particles of detritic (natural) origin, and therefore, magnetic measurements on tree leaves can help to identify hotspots where fine particles are more abundant. Elemental particle-induced X-ray emission analysis of tree leaves showed the presence of a number of elements associated with vehicular emissions, in particular Cu, Zn, Fe, K and S which are present at every site, and As, Se, V, Ni, Sr, Zr, Mo and Pb identified at some sites. We observed a correlation between magnetic parameters and the concentrations of S and Br as well as Cu to a smaller extent. Moreover, this study shows the importance of selecting carefully the tree species as well as the location of trees in order to optimize phytoremediation.

PM10 variation, composition, and source analysis in Tuscany (Italy) following the COVID-19 lockdown restrictions

Abstract. To control the spread of COVID-19, exceptional restrictive measures were taken in March 2020 that imposed a radical change on the lifestyle of millions of citizens around the world, albeit for a short period. The national lockdown, which lasted from 10 March to 18 May 2020 in Italy, was a unique opportunity to observe the variation in air quality in urban environments under conditions comprising almost total traffic restriction and a strong reduction in work activities. In this paper, the data from 17 urban monitoring sites in Tuscany are presented, and the PM and NO2 concentrations in the 2 months before the start of the lockdown and the 2 months after lockdown are compared with the corresponding months of the previous 3 years. The results show that the total loads of PM2.5 and PM10 (particulate matter with an aerodynamic diameter smaller than 2.5 and 10 µm, respectively) decreased, but they did not exhibit significant changes compared to previous years, whereas NO2 underwent a drastic reduction. For three of these sites, the chemical composition of the collected samples was measured using thermal–optical techniques, ion chromatography, and particle-induced X-ray emission analysis, and the application of multivariate positive matrix factorization analysis also allowed for PM10 source identification and apportionment. Using these analyses, it was possible to explain the low sensitivity of PM10 to the lockdown effects as being due to different, sometimes inverse, behaviors of the different sources that contribute to PM. The results clearly indicate a decline in pollution levels related to urban traffic and an increase in the concentration of sulfate for all sites during the lockdown period.

Heavy metals research in Nigeria: a review of studies and prioritization of research needs.

Nigeria is experiencing continuous economic and industrial transformations, typical of many developing nations. In addition to its well-established oil industry, which is infamous for exuding various kinds of pollutants, there are increased mining operations, indiscriminate disposal and burning of wastes, illegal oil refinery and terroristic insurgency, all poised to increase the levels of heavy metal contaminants in the Nigerian environment. A recent revelation indicates that about 2 million people in South-western Nigeria alone could potentially be poisoned by lead (Pb) and mercury (Hg), emanating from illegal mining operations. This further underscores the importance of investigations of toxic trace metal levels in the country. The current review of 148 research articles was conducted to provide an understanding of the scope of heavy metals research in Nigeria and to prioritize needed research. The review recognized that the scope of heavy metals studies has been wide, covering matrices such as cosmetics, human blood, hair, medicines, foods, beverages, water, air, soil and crude oil. However, important toxic metals, especially mercury (Hg), arsenic (As) and antimony (Sb), are largely under-investigated. Also, there is a need for more studies to be conducted in the northern part of the country. Furthermore, studies need to focus on marine environments rather than the freshwater ecosystems alone. Techniques such as the inductively coupled plasma-optical emission spectrometry (ICP-OES) and particle-induced X-ray emission (PIXE) analyses are herein recommended to bridge the data gap and to overcome limitations in trace metals analyses in the Nigerian total environment.

Improving the accuracy of alpha particle induced X-ray emission analysis: The role of multiple ionization K X-ray satellites

Wavelength-dispersive X-ray spectrometry is used to examine the influence of multiple ionization satellites induced by 3–5 MeV energy helium ion beams upon the accuracy of particle-induced X-ray emission analysis (PIXE). The work extends our prior study of elements magnesium, aluminum and silicon and their oxides to elements phosphorus, chlorine, potassium, calcium, titanium and chromium and, for the latter two, their oxides. Fitting of the spectra with Voigtian peaks enables construction of a database that comprises the mean energies and the relative intensities of up to four distinct satellite groupings. This database provides an empirical means for inclusion of one peak per satellite group when modelling energy-dispersive spectra. This is a useful step towards improving the accuracy of PIXE analysis of materials using helium beams; an example of this is provided using a spectrum recorded by the Curiosity rover on Mars.

One-pot synthesis of silica-gel-based adsorbent with Schiff base group for the recovery of palladium ions from simulated high-level liquid waste

A simple solvothermal reaction was used to prepare a 3-aminopropyl-functionalized silica-gel-based adsorbent for adsorbing Pd(II) from the nitric acid solution. Scanning electron microscopy, fourier transform infrared spectroscopy, and thermogravimetry analysis were performed on the as-synthesized adsorbent to demonstrate the successful introduction of Schiff base groups. Batch experiments were used to investigate the effects of contact time, nitric acid concentration, solution temperature, and adsorption capacity. It is worth noting that the prepared adsorbent exhibited a higher affinity toward Pd(II) with the uptake approximately 100% even in a 2 M HNO3 solution. At an equilibrium time of 5 h, the maximum adsorption capacity of Pd(II) was estimated to be 0.452 mmol/g. The adsorbed Pd(II) could be completely eluted by dissolving 0.2 M thiourea solution in 0.1 M HNO3. Using a combination of particle-induced X-ray emission analysis and an X-ray photoelectron spectrometer, the adsorbed Pd was found to be uniformly distributed on the surface of the prepared adsorbent and the existing species were Pd(II) and zero-valent Pd(0). Due to the desirable performances, facile preparation method, and abundant raw material source, the prepared adsorbent demonstrated a high application potential in the recovery of Pd(II) from simulated high-level liquid waste treatment.

Non-destructive analyses of copper alloys and silver items from Voitenki. The recycling of metal in Cherniakhov culture

Brooches, belt buckles and other metal objects with a specific design are considered characteristic of Cherniakhov culture. In contrast with well-known typologies, the metal composition of these objects has rarely been investigated. Forty-four artefacts from the settlement and cemetery at Voitenki (east Ukraine) were chosen for metal analysis. The fibulae selected, for example, consist of crossbow tendril brooches, crossbow brooches with a closed catch-plate, brooches with a high catch-plate, and other types. A total of 38 finds were made of non-ferrous metal; for six objects, silver was presumed. The precise metal composition was determined by PIXE (particle-induced X-ray emission) analysis. Based on this method, copper, bronze and brass could be determined as material for the brooches and buckles. The bronze objects were divided into forged bronze and cast bronze; furthermore, mixed material was detected. But these groups and subgroups of metal do not coincide with archaeological types. Crossbow tendril brooches were first of all made of copper, although some consist of bronze or brass. Cast bronze was used for manufacturing some cast types of brooches. The producer probably intentionally selected this material to cast. But on the other hand, it seems that the producer used the material that was available, for example, cast bronze for forged brooches. For silver finds, the PIXE analysis detected a high content of this metal. A comparison of the results with analyses of Roman silver denarii led us to the hypothesis that such Roman coins were used as ‘raw material’ for manufacturing these silver items.

Recovery of cesium ions from seawater using a porous silica-based ionic liquid impregnated adsorbent

A porous silica-based adsorbent was prepared by impregnating the pores of a silica support with the extractant 1,3-[(2,4-diethylheptylethoxy)oxy]-2,4-crown-6-calix[4]arene (Calix[4]arene-R14) and an additive agent 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C2mim + NTf2−) as the materials to remove cesium(I) (Cs+) ions from seawater. The as-prepared adsorbent showed excellent adsorption performance toward Cs+ ions, with adsorption equilibrium reached within 2 h and an adsorption amount of 0.196 mmol/g observed. The solution pH, temperature, and the presence of coexisting metal ions were found to have almost no effect on Cs+ adsorption. The adsorption mechanism was considered to proceed via ion exchange between Cs+ and C2mim+. In addition, the particle-induced X-ray emission analysis results further clarified that the adsorbed Cs+ ion species on the adsorbent was in the form of both CsCl and CsBr.

Invasive and Non-Invasive Analyses of Ochre and Iron-Based Pigment Raw Materials: A Methodological Perspective

Naturally occurring and deeply coloured iron-bearing materials were exploited very early on by human populations. The characterization of these materials has proven useful for addressing several archaeological issues, such as the study of technical behaviors, group mobility, and the reconstruction of cultural dynamics. However, this work poses some critical methodological questions. In this paper, we will review ochre studies by focusing on the analytical methods employed, the limits of non-invasive methods, as well as examples of some quality research addressing specific issues (raw material selection and provenience, heat treatment). We will then present a methodological approach that aims to identify the instrumental limits and the post-depositional alterations that significantly impact the results of the non-invasive analysis of cohesive ochre fragments from Diepkloof rock Shelter, South Africa. We used ochre materials recuperated in both archaeological and geological contexts, and we compared non-invasive surface analyses by XRD, scanning electron microscopy coupled with dispersive X-ray spectrometry (SEM-EDXS), and particle-induced X-ray emission (PIXE) with invasive analysis of powder pellets and sections from the same samples. We conclude that non-invasive SEM-EDXS and PIXE analyses provide non-representative results when the number of measurements is too low and that post-depositional alterations cause significant changes in the mineralogical and major element composition at the surface of archaeological pieces. Such biases, now identified, must be taken into account in future studies in order to propose a rigorous framework for developing archaeological inferences.

Adsorption of titanium dioxide nanoparticles onto zebrafish eggs affects colonizing microbiota

Teleost fish embryos are protected by two acellular membranes against particulate pollutants that are present in the water column. These membranes provide an effective barrier preventing particle uptake. In this study, we tested the hypothesis that the adsorption of antimicrobial titanium dioxide nanoparticles onto zebrafish eggs nevertheless harms the developing embryo by disturbing early microbial colonization. Zebrafish eggs were exposed during their first day of development to 2, 5 and 10 mg TiO2 L−1 (NM-105). Additionally, eggs were exposed to gold nanorods to assess the effectiveness of the eggs’ membranes in preventing particle uptake, localizing these particles by way of two-photon microscopy. This confirmed that particles accumulate onto zebrafish eggs, without any detectable amounts of particles crossing the protective membranes. By way of particle-induced X-ray emission analysis, we inferred that the titanium dioxide particles could cover 25–45 % of the zebrafish egg surface, where the concentrations of sorbed titanium correlated positively with concentrations of potassium and correlated negatively with concentrations of silicon. A combination of imaging and culture-based microbial identification techniques revealed that the adsorbed particles exerted antimicrobial effects, but resulted in an overall increase of microbial abundance, without any change in heterotrophic microbial activity, as inferred based on carbon substrate utilization. This effect persisted upon hatching, since larvae from particle-exposed eggs still comprised higher microbial abundance than larvae that hatched from control eggs. Notably, pathogenic aeromonads tolerated the antimicrobial properties of the nanoparticles. Overall, our results show that the adsorption of suspended antimicrobial nanoparticles on aquatic eggs can have cascading effects across different life stages of oviparous animals. Our study furthermore suggests that aggregation dynamics may occur that could facilitate the dispersal of pathogenic bacteria through aquatic ecosystems.