Showing papers on "Fluorescence spectrometry published in 2016"

Utilizing portable X-ray fluorescence spectrometry for in-field investigation of pedogenesis

Abstract: In recent years portable X-ray fluorescence (pXRF) spectrometers have been recognised as an in-field tool for soil analyses as they offer rapid, real-time, simultaneous multi-element analysis of soil samples with no or minimal sample preparation. Portable XRF has been used quite extensively to estimate the degree of soil contamination with heavy metals and to measure the concentration of elements in soils that are important for the soil's fertility, but more recently it has also been used to calibrate for a range of soil chemical and physical properties to perform digital soil morphometrics. However, this still relatively new technology also offers an opportunity for soil scientists to investigate processes of pedogenesis in the field, which in turn will complement the in-field descriptions of soils profoundly. Here, we employed a handheld pXRF spectrometer to investigate the pedogenesis pathways and likely parent materials of three different soil types, utilizing elemental concentration data and geochemical indices. Our study site, a property called ‘Nowley’, is situated on the Liverpool Plains in the Spring Ridge district on the North West Slopes of New South Wales, Australia, in one of the most versatile dryland cropping regions of the continent. The variation in soil types and parent materials across the property offers an unique opportunity to study the impact of parent materials and topography on soil formation. A total of three soil pits were excavated to a depth of 1.0 m to expose the lower B horizons. Soil pit faces were then scanned at 0.1 m depth increments starting from the top of the soil profile to the lowest B horizon exposed. Our results show that elemental data acquired in field condition, which are affected by sample heterogeneities and soil moisture content, are comparable to elemental data acquired in air-dried, ground condition, as geochemical index values show similar trends down the soil profile. We found that the use of pXRF is a very effective in-field tool to assess pedogenic pathways and parent material origin, because of the instant computation of weathering indices and elemental ratios. We conclude that pXRF can be applied successfully and readily to study the soil's weathering history and identify processes of soil formation in the field.

Mixed-ligand copper(II) Schiff base complexes: the role of the co-ligand in DNA binding, DNA cleavage, protein binding and cytotoxicity

Abstract: Four novel mononuclear Schiff base copper(ii) complexes, namely, [Cu(L)(OAc)]·H2O (), [Cu(HL)(C2O4)(EtOH)]·EtOH (), [Cu(L)(Bza)] () and [Cu(L)(Sal)] () (HL = 1-(((2-((2-hydroxypropyl)amino)ethyl)imino)methyl)naphthalene-2-ol), Bza = benzoic acid, Sal = salicylic acid), were synthesized and characterized by X-ray crystallography, elemental analysis and infrared spectroscopy. Single-crystal diffraction analysis revealed that all the complexes were mononuclear molecules, in which the Schiff base ligand exhibited different coordination modes and conformations. The N-HO and O-HO inter- and intramolecular hydrogen bonding interactions linked these molecules into multidimensional networks. Their interactions with calf thymus DNA (CT-DNA) were investigated by UV-visible and fluorescence spectrometry, as well as by viscosity measurements. The magnitude of the Kapp values of the four complexes was 10(5), indicating a moderate intercalative binding mode between the complexes and DNA. Electrophoresis results showed that all these complexes induced double strand breaks of pUC19 plasmid DNA in the presence of H2O2 through an oxidative pathway. In addition, the fluorescence spectrum of human serum albumin (HSA) with the complexes suggested that the quenching mechanism of HSA by the complexes was a static process. Moreover, the antiproliferative activity of the four complexes against HeLa (human cervical carcinoma) and HepG-2 (human liver hepatocellular carcinoma) cells evaluated by colorimetric cell proliferation assay and clonogenic assay revealed that all four complexes had improved cytotoxicity against cancer cells. Inspiringly, complex , with salicylic acid as the auxiliary ligand, displayed a stronger anticancer activity, suggesting that a synergistic effect of the Schiff base complex and the nonsteroidal anti-inflammatory drug may be involved in the cell killing process. The biological features of mixed-ligand copper(ii) Schiff base complexes and how acetic auxiliary ligands manipulate these features are also discussed.

Recent advances in the determination of elemental impurities in pharmaceuticals – Status, challenges and moving frontiers

Abstract: Elemental impurities have been regulated in pharmaceutical products for many decades. Metal impurities such as As, Cd, Cu, Pb, Hg, V and Pt in pharmaceuticals and drugs are known to originate from sources like raw materials, catalysts, metal reagents and even manufacturing equipments. An account of the recent changes implemented by the European Pharmacopoeia (EP), the United States Pharmacopoeia (USP) and other International regulatory bodies for constraining inorganic impurities in pharmaceutical and drug products coupled with new strategies to be adopted for heavy metal analyses is presented. Rapid methods of screening during quality control operations, and a brief account of classical spectrophotometry and the role of instrumental techniques such as atomic absorption spectrometry (AAS), X-ray fluorescence spectrometry (XRF), instrumental neutron activation analysis (INAA), inductively coupled plasma atomic emission spectrometry (ICP-AES) and the inductively coupled plasma mass spectrometry (ICP-MS) for the accurate determination of inorganic impurities in pharmaceutical materials are presented.

Chemical Composition of Microbe-Derived Dissolved Organic Matter in Cryoconite in Tibetan Plateau Glaciers: Insights from Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Analysis.

Abstract: Cryoconite in mountain glaciers plays important roles in glacial ablation and biogeochemical cycles. In this study, the composition and sources of dissolved organic matter (DOM) in cryoconite from the ablation regions of two Tibetan Plateau glaciers were determined using electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and fluorescence spectrometry. A marked absorbance between 300 and 350 nm in the DOM absorption spectra was observed which was consistent with microbe-derived mycosporine-like amino acids. Fluorescence excitation–emission matrices showed that DOM had intense signals at protein-like substance peaks and weak signals at humic-like substance peaks. The high-resolution mass spectra of FT-ICR-MS showed cryoconite DOM from both glaciers contained diverse lignins, lipids, proteins, and unsaturated hydrocarbons. The lipids and proteins were consistent with material from microbial sources, and the lignins and unsaturated hydrocarbons were probably ...

Essential and toxic elements in seaweeds for human consumption.

Abstract: Essential elements (K, Ca, P, S, Cl, Mn, Fe, Cu, Zn, Ni, Br, and I) and nonessential or toxic elements (Al, Ti, Si, Rb, Sr, As, Cd, Sn, and Pb) were determined by energy-dispersive polarized x-ray fluorescence spectrometry in 14 seaweeds purchased in local specialty stores in Italy and consumed by humans. The differences in elements between the algae species reached up to 2-4 orders of magnitude. Lithothamnium calcareum showed the highest levels of Ca, Al, Si, Fe, and Ti. Palmaria palmata showed the highest concentrations of K, Rb, and Cl. The highest content of S was in Chondrus crispus. Laminaria digitata contained the highest concentrations of total As, Cd, Sn, Br, and I. The highest concentration of Zn was in Chlorella pyrenoidosa. Ulva lactuca displayed the highest levels of Cu, Ni, Mn, and Pb. Iodine levels ranged from 3.4 in Chlorella pyrenoidosa to 7316 mg/kg(dry) in Laminaria digitata. The nutrimental importance of essential elements was assessed using nutritional requirements. The results showed that the consumption of algae might serve as an important source of the essential elements. Health risk due to the toxic elements present in seaweed was estimated using risk estimators. Total As, Cd, and Pb concentrations ranged from <1 to 67.6, to 7.2 and to 6.7 mg/kg(dry) respectively; therefore, their contribution to total elemental intake does not appear to pose any threat to the consumers, but the concentrations of these elements should be controlled to protect the consumer against potential adverse health risks.

Preconcentration of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pb(II) with ethylenediamine-modified graphene oxide

Abstract: We describe a novel solid phase sorbent that was synthesized by coupling graphene oxide (GO) to ethylenediamine (EDA). This nanomaterial (referred to as GO-EDA) is capable of adsorbing the ions of iron, cobalt, nickel, copper, zinc and lead. The ethylenediamine-modified graphene oxide was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. The analytical procedure relies on (a) sorption of metal ions on GO-EDA dispersed in aqueous samples; (b) filtering, and (c) direct submission of the filter paper to energy-dispersive X-ray fluorescence spectrometry. This kind of dispersive micro-solid phase extraction was optimized with respect to pH values, concentration of GO-EDA, contact time, and the effects of interfering ions and humic acid on recovery of determined elements. Under optimized conditions, the recoveries of spiked samples range from 90 to 98 %. The detection limits are 0.07, 0.10, 0.07, 0.08, 0.06 and 0.10 ng mL−1 for Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pb(II), respectively. The method has a relative standard deviation of <6 %, and its accuracy was verified by analysis of two standard reference materials [LGC6016 (estuarine water) and BCR-610 (groundwater)]. It was successfully applied to the determination of trace amounts of these metal ions in water samples.

Size-segregated urban particulate matter: mass closure, chemical composition, and primary and secondary matter content.

Abstract: Forty-nine components of ambient particulate matter (PM) in size-fractionated PM were investigated at an urban background site in Katowice (Silesian Agglomeration in Southern Poland) in the non-heating season of 2012. PM was analyzed for two groups of carbon compounds (organic (OC) and elemental (EC) carbon, Lab OC-EC Aerosol Analyzer), five major water-soluble ions (NH4 +, Cl−, SO4 2−, NO3 −, and Na+ contents in PM water extracts, ion chromatography), 26 elements (X-ray fluorescence spectrometry), and 16 polycyclic aromatic hydrocarbons (PAHs, gas chromatography). The distributions of the masses of these components among 13 basic PM fractions were determined, and chemical mass closure was checked for each of these fractions separately. The particles having their aerodynamic diameters in the interval 0.03–0.26 μm, the fraction PM0.03–0.26, contributed about 13 % to the total PM mass. This PM fraction consisted of primary particles predominantly composed of various inorganic compounds, primary organic compounds, and, in lesser amounts, of elemental carbon, secondary ions, and secondary organic compounds. The second particle fraction, PM0.26–1.6, consisted mainly of secondary matter, and its mass contribution to the total PM mass was about 59 %. The third fraction, PM1.6–40, was a fraction of coarse particles composed of mineral/soil and organic matter and elemental carbon. It contributed to the PM mass about 28 %. For each of PM0.03–0.26, PM0.26–1.6, and PM1.6–40, the health hazard from its 16 PAH contents was determined by computing toxicity factors. PM0.26–1.6 posed the greatest health hazard from the mixture of the 16 PAHs that it contained, PM1.6–40 was the next, and the hazard from the PM0.03–0.26-bound 16 PAHs was the smallest. The molecular diagnostic ratios computed for these three fractions were specific for coal and wood combustion; some indicated the road traffic effects.

Quantification of nitroaromatic compounds in atmospheric fine particulate matter in Hong Kong over 3 years: field measurement evidence for secondary formation derived from biomass burning emissions

Abstract: Environmental context Nitroaromatic compounds constitute an important portion of brown carbon and thereby contribute to the light-absorbing properties of atmospheric aerosols. We report their abundance in Hong Kong over 3 years and show that they were mainly associated with aged biomass burning particles. Knowledge of the abundance and sources of nitroaromatic compounds could assist in evaluating their contribution to brown carbon and in apportioning secondary organic aerosols from biomass burning sources. Abstract Biomass burning is a major source of atmospheric aerosols on both global and regional scales. Among the large number of unidentified organic compounds related to biomass burning, nitroaromatic compounds (NACs) have drawn attention because of their UV light-absorbing ability. In this study, an analytical method based on liquid chromatography–mass spectrometry was used to quantify a group of NACs (nitrophenol, methylnitrophenols, dimethylnitrophenol, nitrocatechol and methylnitrocatechols) in aerosol samples. The nitrocatechol–metal complex interference, sample matrix effects, sample stability, precision and reproducibility were investigated. The method detection limits ranged from 0.10 to 0.23ngmL–1 and the recoveries for the target NACs were in the range of 96–102%. The method was applied to a total of 184 ambient PM2.5 samples (particulate matter of 2.5µm or less in aerodynamic diameter) collected at an urban site in Hong Kong over 3 years (2010–2012). The NACs quantified showed a distinct seasonal variation with higher concentrations in autumn and winter (3.6–21.0ngm–3), coinciding with more biomass burning activities coming from the regions west and north-east to Hong Kong, and lower levels during spring and summer (0.3–3.8ngm–3). The good correlations between NACs and levoglucosan (R=0.82), a known biomass burning tracer compound, support the common origin from biomass burning. Moderate to good correlations between NACs and nitrate suggest that they might be products of secondary formation processes involving the same precursor gases (e.g. NOx). Additional lines of circumstantial evidence were also found and presented in the paper to support secondary formation derived from biomass burning as the main contributing source of NACs.

Characteristics of Different Sized Slag Particles from Entrained-Flow Coal Gasification

Abstract: Gasification slags are byproducts of the coal gasification process, including fine slags (slags from filter) and coarse slags (slags from lock hopper). The characteristics of gasification slags with different particle sizes were investigated by the loss-on-ignition (LOI) method, scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS), pore structure analysis, X-ray diffractometry (XRD), and X-ray fluorescence spectrometry (XRF). The relationships between the particle size and the characteristics of slags, which include residual carbon content, surface characteristics, pore structure, crystal mineral content, and ash composition, were analyzed and obtained. For fine slags, carbon content, specific surface area, porosity, and crystal content increase with particle size. For coarse slags, medium sized (105–280 μm) particles contain the most residual carbons and crystal minerals, followed by the smaller (0–105 μm) particles. Si/Al/Ca/Mg/K tends to concentrate in larger coarse slags, while...

Mobile Spectroscopic Instrumentation in Archaeometry Research.

Abstract: Mobile instrumentation is of growing importance to archaeometry research. Equipment is utilized in the field or at museums, thus avoiding transportation or risk of damage to valuable artifacts. Many spectroscopic techniques are nondestructive and micro-destructive in nature, which preserves the cultural heritage objects themselves. This review includes over 160 references pertaining to the use of mobile spectroscopy for archaeometry. Following a discussion of terminology related to mobile instrumental methods, results of a literature survey on their applications for cultural heritage objects is presented. Sections devoted to specific techniques are then provided: Raman spectroscopy, X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, laser-induced breakdown spectroscopy, and less frequently used techniques. The review closes with a discussion of combined instrumental approaches.

Repeated catastrophic valley infill following medieval earthquakes in the Nepal Himalaya

Abstract: Geomorphic footprints of past large Himalayan earthquakes are elusive, although they are urgently needed for gauging and predicting recovery times of seismically perturbed mountain landscapes. We present evidence of catastrophic valley infill following at least three medieval earthquakes in the Nepal Himalaya. Radiocarbon dates from peat beds, plant macrofossils, and humic silts in fine-grained tributary sediments near Pokhara, Nepal's second-largest city, match the timing of nearby M > 8 earthquakes in ~1100, 1255, and 1344 C.E. The upstream dip of tributary valley fills and x-ray fluorescence spectrometry of their provenance rule out local sources. Instead, geomorphic and sedimentary evidence is consistent with catastrophic fluvial aggradation and debris flows that had plugged several tributaries with tens of meters of calcareous sediment from a Higher Himalayan source >60 kilometers away.

Molecular composition of urban organic aerosols on clear and hazy days in Beijing: a comparative study using FT-ICR MS

Abstract: Environmental context China has been experiencing severe particulate pollution and frequent haze episodes in recent years. We compare the molecular composition of urban organic aerosols on clear and hazy days in Beijing by high-resolution mass spectrometry. The comparative study shows that oxidation, sulfation and nitrification processes actively involve precursors of anthropogenic origin in the Beijing polluted urban atmosphere. Abstract Haze has frequently affected many cities and threatened human health in China. Detailed knowledge of the chemical composition of secondary organic aerosol provides fundamental information in the study of the formation mechanism of haze and its adverse effects on human health. In our work, dichloromethane and water extracts of ambient aerosols collected on hazy and clear days in Beijing were characterised by negative-ion electrospray ionisation and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Formulae in four elemental compositional groups, namely CHOS, CHONS, CHO and CHON, were identified relying on the ultrahigh resolution and mass accuracy of FT-ICR MS. Significantly more compounds were detected and the peaks were much more intense in the hazy day samples, especially for the CHOS, CHONS and CHON formula groups. Organosulfates (OS) and nitrooxy-organosulfates (nitrooxy OS) were the major forms of CHOS and CHONS formulae respectively, and their numbers more than tripled on the hazy days. Under the severely polluted conditions in Beijing, the compositional distribution of the OS and nitrooxy OS exhibited distinct features such as intense peaks of low double-bond equivalent (DBE) (DBE=0, 1 for OS and DBE=1, 2 for nitrooxy OS) and low degree oxidation, of medium DBE (DBE=2, 3 for OS and DBE=3, 4 for nitrooxy OS), and of high DBE (DBE ≥ 4 for OS and DBE ≥ 5 for nitrooxy OS). The likely respective candidates for these could be aliphatic OS having a low degree of oxidation, biogenic OS and many aromatics and polycyclic aromatic hydrocarbon (PAH)-derived OS. The CHON formulae observed on hazy days were double those on clear days and had higher DBE values and larger O/N ratios. Slightly more CHO compounds were detected in the hazy-day samples and they had higher DBE values and more oxygen atoms. The comparative study suggests that oxidation, sulfation and nitrification processes actively involve precursors of anthropogenic origin in the Beijing polluted urban atmosphere.

Heavy metal bioaccumulation by wild edible saprophytic and ectomycorrhizal mushrooms.

Abstract: Heavy metals cause serious problems in the environment, and they can be accumulated in organisms, especially in the higher fungi. The concentration of Ni, Cr, Pb, Cd, and Hg in 10 species of edible mushrooms in Medvednica Nature Park, Croatia was therefore determined. In addition, the similarity between the studied species was determined by cluster analysis based on concentrations of the aforementioned metals in the fruiting bodies. The contents of nickel, chromium, lead, cadmium, and mercury in the fruiting bodies of mushrooms were obtained by X-ray fluorescence spectrometry. The highest concentrations of Ni (3.62 mg kg−1), Cr (3.01 mg kg−1), and Cd (2.67 mg kg−1) were determined in Agaricus campestris. The highest concentration of Pb (1.67 mg kg−1) was determined in Macrolepiota procera, and the highest concentration of Hg (2.39 mg kg−1) was determined in Boletus edulis. The concentration of all heavy metals significantly differed (p < 0.001) between examined saprophytic and ectomycorrhizal mushrooms. Considering anatomical part of the fruiting body (cap-stipe), a considerably higher concentration of the analyzed elements was found in the cap for all mushroom species. According to calculated bioconcentration factors, all the examined species were found to be bioexclusors of Ni, Cr, and Pb and bioaccumulators of Cd and Hg. Cluster analysis performed on the basis of the accumulation of the studied metals revealed great phenotypic similarity of mushroom species belonging to the same genus and partial similarity of species of the same ecological affiliation.

Tetra- and Hexavalent Uranium Forms Bidentate-Mononuclear Complexes with Particulate Organic Matter in a Naturally Uranium-Enriched Peatland.

Abstract: Peatlands frequently serve as efficient biogeochemical traps for U. Mechanisms of U immobilization in these organic matter-dominated environments may encompass the precipitation of U-bearing mineral(oid)s and the complexation of U by a vast range of (in)organic surfaces. The objective of this work was to investigate the spatial distribution and molecular binding mechanisms of U in soils of an alpine minerotrophic peatland (pH 4.7–6.6, Eh = −127 to 463 mV) using microfocused X-ray fluorescence spectrometry and bulk and microfocused U L3-edge X-ray absorption spectroscopy. The soils contained 2.3–47.4 wt % organic C, 4.1–58.6 g/kg Fe, and up to 335 mg/kg geogenic U. Uranium was found to be heterogeneously distributed at the micrometer scale and enriched as both U(IV) and U(VI) on fibrous and woody plant debris (48 ± 10% U(IV), x ± σ, n = 22). Bulk U X-ray absorption near edge structure (XANES) spectroscopy revealed that in all samples U(IV) comprised 35–68% of total U (x = 50%, n = 15). Shell-fit analyses...

Ash Fusion Characteristics of a High Aluminum Coal and Its Modification

Abstract: High aluminum coal (HAC, Al2O3 in its ash content ranges 38–51%) is abundant and plays an important role in energy and chemical product in China. The ash fusion characteristics of HAC and its modification behaviors by coal blending or flux were investigated by ash fusion temperature (AFT) analyzer, X-ray fluorescence spectrometry, X-ray diffractometry combined with normalized reference intensity ratio method, and scanning electron microscopy. The AFT variation is manly dependent on mineral composition and its transformation. A large amount of high melting point (MP) mullite formation results in HAC (Sunjiahao coal, SJH) AFT high. Compare with the coal blending of Shenmu (SM) and Xiangyuan (XY), CaO addition provides a better way to adjust ash fusion characteristics of SJH. For coal blending, that calcium and iron element in low AFT coal react with high MP mineral and then evolve into eutectic and amorphous matter makes the AFT of SJH mixtures decrease. The formations of low MP anorthite, and gehlenite, an...

Analysis of heavy metals in the re-suspended road dusts from different functional areas in Xi'an, China.

Abstract: A study on heavy metal pollution was undertaken in the re-suspended road dusts from different functional areas in Xi'an City of China to investigate the impacts of human activities and land uses on urban environment. The concentrations of Co, Cr, Cu, Mn, Ni, Pb, V, and Zn were determined using X-ray fluorescence spectrometry, and their accumulations were analyzed using enrichment factor. Correlation analysis, principal component analysis, and cluster analysis, combined with the concentration property and enrichment factor, were used to identify the possible sources of heavy metals investigated. The investigated re-suspended road dusts had Co, Cr, Cu, Pb, and Zn concentrations higher than background levels. Samples from different functional areas had diverse heavy metal concentration levels. Co, Cr, Cu, Pb, and Zn presented moderate/significant enrichment in the samples. The source analyses indicated that Mn, Ni, V, Pb, and Zn had the mixed sources of nature and traffic, Cr and Cu mainly originated from traffic source, while Co was primarily derived from construction source. Traffic and construction activities had a significant impact on urban environment. This preliminary research provides a valuable basis for urban environment protection and management.

Influence of ZrO2, SiO2, Al2O3 and TiO2 nanoparticles on maize seed germination under different growth conditions.

Abstract: The focus of this investigation is to evaluate the phytotoxicity of selected metal oxide nanoparticles and microparticles as a function of maize seed germination and root elongation under different growth conditions (Petri plate, cotton and soil). The results of seed germination and root elongation experiments reveal that all the growth conditions show almost similar results. Alumina (Al2O3) and titania (TiO2) nanoparticles significantly reduce the germination percentage, whereas silica (SiO2) nanoparticles and microparticles enhance the same. The results of nanoparticles and microparticles of zirconia (ZrO2) are found to be same as those of controls. Root elongation is enhanced by SiO2 nanoparticles and microparticles treatment, whereas inhibition is observed with Al2O3 and TiO2 nanoparticles and microparticles. The X-ray fluorescence spectrometry data of the treated and control seed samples show that seeds uptake SiO2 particles to a greater extent followed by TiO2, Al2O3 and ZrO2. In addition, the uptake of nanoparticles is found to be greater than that of microparticles. Thus, the tested metal oxides penetrated seeds at the nanoscale as compared with the microscale. This study clarifies phytotoxicity of nanoparticles treated in different growth substrates and highlights the impact of nanoparticles on environment and agricultural systems.

The meteoritic origin of Tutankhamun's iron dagger blade

Abstract: Scholars have long discussed the introduction and spread of iron metallurgy in different civilizations. The sporadic use of iron has been reported in the Eastern Mediterranean area from the late Neolithic period to the Bronze Age. Despite the rare existence of smelted iron, it is generally assumed that early iron objects were produced from meteoritic iron. Nevertheless, the methods of working the metal, its use, and diffusion are contentious issues compromised by lack of detailed analysis. Since its discovery in 1925, the meteoritic origin of the iron dagger blade from the sarcophagus of the ancient Egyptian King Tutankhamun (14th C. BCE) has been the subject of debate and previous analyses yielded controversial results. We show that the composition of the blade (Fe plus 10.8 wt% Ni and 0.58 wt% Co), accurately determined through portable x-ray fluorescence spectrometry, strongly supports its meteoritic origin. In agreement with recent results of metallographic analysis of ancient iron artifacts from Gerzeh, our study confirms that ancient Egyptians attributed great value to meteoritic iron for the production of precious objects. Moreover, the high manufacturing quality of Tutankhamun's dagger blade, in comparison with other simple-shaped meteoritic iron artifacts, suggests a significant mastery of ironworking in Tutankhamun's time.

Novel Gold Nanoparticles Reduced by Sargassum glaucescens: Preparation, Characterization and Anticancer Activity.

Abstract: The current study investigated the anticancer properties of gold nanoparticles (SG-stabilized AuNPs) synthesized using water extracts of the brown seaweed Sargassum glaucescens (SG). SG-stabilized AuNPs were characterized by ultraviolet-visible spectroscopy, transmission and scanning electron microscopy, and energy dispersive X-ray fluorescence spectrometry. The SG-stabilized AuNPs were stable and small at 3.65 ± 1.69 nm in size. The in vitro anticancer effect of SG-stabilized AuNPs was determined on cervical (HeLa), liver (HepG2), breast (MDA-MB-231) and leukemia (CEM-ss) cell lines using fluorescence microscopy, flow cytometry, caspase activity determination, and MTT assays. After 72 h treatment, SG-stabilized AuNPs was shown to be significant (p < 0.05) cytotoxic to the cancer cells in a dose- and time-dependent manner. The IC50 values of SG-stabilized AuNPs on the HeLa, HepG2, CEM-ss, MDA-MB-231 cell lines were 4.75 ± 1.23, 7.14 ± 1.45, 10.32 ± 1.5, and 11.82 ± 0.9 μg/mL, respectively. On the other hand, SG-stabilized AuNPs showed no cytotoxic effect towards the normal human mammary epithelial cells (MCF-10A). SG-stabilized AuNPs significantly (p < 0.05) arrest HeLa cell cycle at G2/M phase and significantly (p < 0.05) activated caspases-3 and -9 activities. The anticancer effect of SG-stabilized AuNPs is via the intrinsic apoptotic pathway. The study showed that SG-stabilized AuNPs is a good candidate to be developed into a chemotherapeutic compound for the treatment of cancers especially cervical cancer.