Inductively Coupled Optical Emission Spectrometry Research Articles

Bones or Stones: How Can We Apply Geophysical Techniques in Bone Research?

Some studies have used physical techniques for the assessment of bone structure and composition. However, very few studies applied multiple techniques, such as those described below, at the same time. The aim of our study was to determine the chemical and mineralogical/organic composition of bovine tibial bone samples using geophysical/geochemical reference techniques. X-ray diffraction (XRD), thermogravimetry (TG), Fourier-transform infrared spectrometry with attenuated total reflectance accessory (FTIR-ATR), inductively coupled mass spectrometry (ICP-MS) and inductively coupled optical emission spectrometry (ICP-OES) were applied to measure the organic and inorganic composition of 14 bovine bone samples. In addition, peripheral quantitative CT (QCT) was used to assess BMD in these bones. We were able to define the total composition of the studied bone samples. ICP-OES and ICP-MS techniques were used to determine the major and trace element composition. The X-ray analysis could detect inorganic crystalline compounds of bones, such as bioapatite, and its degree of ordering, indicating whether the bones belong to a younger or older individual. The total volatile content of the samples was calculated using TG and resulted in about 35 weight% (wt%). This, together with the 65 wt% total resulting from the chemical analysis (i.e., inorganic components), yielded a total approaching 100 wt%. As a large portion of the volatile content (H2O, CO2, etc.) was liberated from the organic components and, subordinately, from bioapatite, it could be concluded that the volatile-to-solid ratio of the examined bone samples was ~35:65. The FTIR-ATR analysis revealed that the organic portion consists of collagens containing amide groups, as their typical bands (OH, CH, CO, NC) were clearly identified in the infrared spectra. Numerous parameters of bone composition correlated with BMD as determined by QCT. In conclusion, we performed a complex evaluation of bovine bones to test multiple geophysical/geochemical techniques in bone research in association with QCT bone densitometry. From a medical point of view, the composition of the studied bones could be reliably examined by these methods.

Microstructural and heavy metal analysis of gallstones prevalent in Jharkhand and its implications in the treatment

ABSTRACT Objectives In the present study the structural and compositional analysis of gallstones was carried out by various characterization techniques. Also, the utility of the study was evaluated on how the findings can enhance the treatment and dissolution therapies of gallstones? Methods Gallstones from the Jharkhand region were analyzed both structurally as well as chemically using Field emission scanning electron microscope (FESEM) and Energy-dispersive X-ray spectroscopy, inductively coupled optical emission spectrometry (ICP-OES), Carbon hydrogen and nitrogen analyzer (CHNS), Nuclear magnetic resonance (NMR), Thermal gravimetric analysis (TGA) and Differential Thermal Analysis (DTA) and other instruments. The content of heavy metal was represented statistically as a mean with standard deviation. Results FESEM analysis unveiled the crystal and globular structure of cholesterol and pigment gallstones respectively. Through ICP-OES analysis metals such as Fe, Mn, Cu, Pb, Cr, Zn etc. were detected in gallstones. FTIR and XRD analysis confirmed the presence of cholesterol and calcium carbonate and other compounds in mixed stones and calcium bilirubinate and bilirubin in pigment gallstones. NMR analysis revealed the presence of monohydrate cholesterol (Crystalline) in Cholesterol and mixed gallstones. Mixed gallstones were found to be predominant in this region in contrast to pigmented stones that were prevalent earlier. Conclusion The present study uncovered the current composition and content of different heavy metals in gallstones of Jharkhand region which can be instrumental in enhancing the dissolution therapies for gallstone treatment. This can serve as a major tool for practitioners for gallstone treatment and change the way they are looked at.

Virus and bacterial removal ability of TiO2 nanowire-based self-supported hybrid membranes

Development and application of hybrid membranes containing multi-component materials are increasing day by day in the fields of environmental protection and water treatment. In this research, the efficiency of titania nanowire (TiO2 NW)-based self-supported hybrid membranes was investigated in the removal of Escherichia coli (E. coli) bacteria and MS2 bacteriophages from contaminated water mimicking the microorganism suspension. Furthermore, toxicology tests on the as-prepared membranes were also performed. TiO2 NWs were coated with iron(III) oxide (Fe2O3) and copper(II) oxide (CuO) nanoparticles, respectively, and cellulose was used as reinforcement material. It was found that, the functionalisation strongly affected the MS2 removal ability of as-prepared membranes, which can be due to the electrostatic interactions between the surface of hybrid membrane and the bacteriophages. The most efficient removal (greater than or equal to 99.99%) was obtained with the TiO2 NW-CuO-cellulose membrane at pH 7.0. The fabricated hybrid membranes were characterized by micro computed tomography (μCT), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), contact angle measurement and inductively coupled optical emission spectrometry (ICP-OES) techniques. This study shows a simple route of the usage of novel and effective inorganic nanowire-based hybrid membranes for bacteria and virus removal, providing new pathways in the field of water filtration technologies.

AVALIAÇÃO DE METAIS POTENCIALMENTE TÓXICOS EM CHORUME PROVENIENTE DE ÁREA DE DEPOSIÇÃO DE RESÍDUOS SÓLIDOS EM BELÉM – PARÁ

EVALUATION OF POTENTIALLY TOXIC METALS IN LEACHES FROM SOLID WASTE DEPOSITION AREA IN BELÉMPARÁ. The formation of solid waste is a global challenge regarding environmental preservation. Due to the lifestyle of modern society, which aims to improve practicality, new products are constantly being released in the market and increasing the formation of waste. The decomposition of waste from various origins produces a dark liquid named leachate, which presents high rates of organic and inorganic compounds. The objective of this study was to assess the concentration of potentially toxic metals in the leachate collected from the Aurá dump. The concentrations of Cd, Cu, Cr, Mn, Ni, Pb, and Zn were evaluated in leachate samples collected in a period of a year, covering two typical seasonal periods of the Amazon region with more and less rainfall. The leachate samples collected in the Aurá dump were determined in the Toxicology Laboratory of Instituto Evandro Chagas (IEC), by means of Plasma/ Inductively Coupled Optical Emission Spectrometry (ICP-OES). The Cr, Mn, and Pb metals analyzed in the slurry samples are in a concentration above the maximum limits specified by CONAMA Resolution No. 430/2011, causing significant environmental concerns.

Characterization of pea seed nutritional value within a diverse population of Pisum sativum.

Micronutrient malnutrition is a global concern that affects more than two billion people worldwide. Pea (Pisum sativum) is a nutritious pulse crop with potential to assist in tackling hidden hunger. Here we report seed ionomic data of 96 diverse pea accessions collected via inductively coupled plasma mass spectrometry (ICP-MS). We found a 100 g serving of peas provides the following average percent daily value for U.S. recommendations: 8% Ca, 39% Mg, 73% Cu, 37% Fe, 63% Mn, 45% Zn, 28% K, and 43% P. Correlations were observed between the majority of minerals tested suggesting strong interrelationships between mineral concentration levels. Hierarchical clustering identified fifteen accessions with high-ranking mineral concentrations. Thirty accessions could be compared to earlier inductively coupled optical emission spectrometry (ICP-OES) data, which revealed significant differences particularly for elements at extreme low or high levels of accumulation. These results improve our understanding of the range of variation in mineral content found in peas and provide additional mineral data resources for germplasm selection.

Variations of Macro- and Microelements in Yellow-Fleshed Cassava (Manihot esculenta Crantz) Genotypes as a Function of Storage Root Portion, Harvesting Time, and Sampling Method

The correct estimation of the mineral content of cassava (Manihot esculenta) genotypes is vital from a nutritional point of view. This study evaluated the effects of the storage root section, maturity, and sampling method on the macro- and microelements in yellow-fleshed cassava root genotypes. In total, 44 genotypes were grown in replicated field trials of 2 sets (set 25 and set 19) and were harvested at 9 and 12 months after planting. Two sampling methods, sampling with a cork borer (A = proximal, B = middle, C = distal or method 1) and sampling without a cork borer (L = Longitudinal or method 2), were used. The minerals of the samples from the two methods were determined using inductively coupled optical emission spectrometry (ICP-OES). K and Mn were the most abundant minerals, and Na, Mo, and Co were the least abundant. Genotype, method, and maturity had a strong influence on mineral concentrations. Harvesting time affected the concentration level of some macro- and microelements in cassava roots. Additionally, Ca, Mg, K, P, Mn, Cu, Ni, and Zn contents were significantly (p < 0.05) higher in the proximal and middle portions for method 1. K and P and Mn and B were positively correlated, but K and Na and Fe and Ni were negatively associated.

Investigation of PM2.5 absorbed with heavy metal elements, source apportionment and their health impacts in residential houses in the North-east region of China

Considering the severe polluted situation (e.g., haze) in China, especially during the heating season, it is of great importance to investigate particle matters with absorbed pollutants aiming at source appointment and mitigation strategies. In this work, air purifier filters were utilized to collect particle samples (i.e.,PM2.5). Metal elements and water-soluble ions in PM2.5 were analyzed by using the techniques of Inductively coupled optical emission spectroscopy (ICP-OES) and ion chromatography. Next, methods of enrichment factor and main factor analysis were adopted to explore the source of metal elements in indoor PM2.5 and other indoor particle matters. The potential risk index (RI) of the metal elements was also calculated to assess exposure-health risk. The results showed that particles in the purifier filter were alkaline, SO42− of the water-soluble ions showing the highest concentration. Four main sources of indoor particles were identified: dust, coal dust, dust produced by industrial production and soil dust, with corresponding contribution rates of 56.8%, 21.2%, 12.9% and 6.4% respectively. The potential RI of the metal elements is higher than 600 implying strong ecological hazards. These findings are important for source appointment of indoor particle pollutants further facilitating future mitigation strategies or techniques towards healthy and sustainable living environments.

Investigating the impact of anthropogenic land use on a hemiboreal lake ecosystem using carbon/nitrogen ratios and coupled-optical emission spectroscopy

Anthropogenic impacts on lake ecosystems have increased substantially towards the present. However, the strength and timing in most cases are not evaluated in detail, missing valuable information on the response and recovery of an aquatic system. In this study, we use the sediment total organic carbon/total nitrogen ratio (C/N) and inductively coupled-optical emission spectroscopy (ICP-OES) elements and the available information about the biological processes to explore anthropogenic land use impact on the lake ecosystem. As a case study we selected a hemiboreal lake Trikātas (Latvia, NE Europe). The Pearson correlation was used to statistically test the correlations of all variables. Our results show that the C/N ratio lowered immediately with the onset of crop cultivation at 500 BCE. Extensive forest clearance and an abrupt increase in land use are reflected through the associated chemical elements from ICP-OES and the increasing presence of herbivore dung spores since 1200 CE. These changes concur with the excess of fish remains suggesting a decrease in fish populations. Interestingly, anthropogenic land use driven erosion and accompanied calcium carbonate (CaCO3) matter influx favoured the abundance of Chara spp. in Lake Trikātas since 500 CE, which currently forms the protected specific habitat-type (H3140) of the European Union. At present, specific submerged macrophyte Chara habitat-type diminished almost entirely due to increased nutrient input, phytoplankton blooming, hypertrophic conditions and reduced light availability. The continued land use practices led to a switch in organic matter source in the lake from macrophytes to solely algal origin. The current study underlines the need of additional methods used to detect the sensitivity of lake ecosystem to external disturbances such as minor anthropogenic land use that might not necessarily be apparent in more traditional analyses such as palynology.

Petrogenesis of South Armorican serpentinized peridotites

Twenty three serpentinite samples collected from five outcrops in south Brittany (Audierne near Quimper, Champtoceaux near Nantes), western France, were studied using optical microscopy, electron microprobe (EMP), inductively-coupled optical emission spectroscopy (ICP-OES), inductively-coupled plasma mass spectrometry (ICP-MS), and laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS). Their bulk-rock major and trace element contents recomputed on an anhydrous basis are broadly characteristic of mantle-derived peridotites, as are the covariation trends of inert elements despite evidence of serpentinization-related remobilization of some fluid-mobile elements (FME; e.g., Ca, La, Ce, Sr, U). One outcrop near Champtoceaux shows fertile lherzolite compositions and chondrite-normalized rare earth element patterns consistent with low (5–7%) degree of mantle partial melting. The other four occurrences are harzburgites displaying higher partial melting degrees (15–25%). Regardless of their degree of fertility, our South Armorican peridotites bear evidence of high-temperature melt/fluid - rock metasomatic interaction yielding an overall enrichment in highly incompatible elements (HIE; Cs, Rb, Ba, Th, U, Pb, La). Hydrous modal metasomatism has been identified in both lherzolites and harzburgites. The lherzolites reacted with HIE-enriched small-volume fluids at P = 1.5–2 Gpa for T > 900 °C that produced a Ti-poor pargasite. The Audierne harzburgites were pervasively refertilized by alkali-rich hydrous melts that precipitated K- and Cr-rich pargasite. Taken as a whole, South Armorican peridotites record a great diversity of protoliths, from supra-subduction zone ophiolites (Audierne) to arc-fore arc provenance.

A method for the quantitative extraction of gold nanoparticles from human bronchoalveolar lavage fluids through a glycerol gradient.

Bronchoalveolar lavage (BAL) is a diagnostic procedure which samples the cellular and non-cellular components of the pulmonary epithelial surface. The inherent biological noise of BAL fluids inhibits their direct mineralogical analysis while currently available particle retrieval protocols are suspected to impose quantitative and qualitative bias on the studied particle load. This study presents a simple method for the near-lossless extraction of citrate-capped gold nanoparticles from human BAL fluids at sub-ppm levels which enables their quantitation and surface characterization. This procedure was modeled according to fundamental principles of particle sedimentation and liquid-liquid interdiffusion and was evaluated by a battery of analytical techniques. The extraction yield of gold nanoparticles ranged from 61 to 86%, with a quantitation limit at 0.5 μg ml-1, as measured by inductively-coupled optical emission spectroscopy. Dynamic light scattering could resolve the hydrodynamic size distribution of extracted particles which returned significantly different photon count rates at various concentrations. Their shape and primary size were easily observable by electron microscopy while atomic force microscopy, Auger electron spectroscopy and X-ray photoelectron spectroscopy could respectively probe the particles' biomolecular corona, detect surface-adsorbed S- and N- species, and identify carbon-based covalent bonds.

Assessment of the Effects Exerted by Acid and Alkaline Solutions on Bone: Is Chemistry the Answer?

The treatment of corpses with extremely acid or basic liquids is sometimes performed in criminal contexts. A thorough characterization by chemical analysis may provide further help to macroscopic and microscopic analysis; 63 porcine bone samples were treated with solutions at different pH (1-14) for immersion periods up to 70 days, as well as in extremely acidic sulfuric acid solutions (9 M/18 M) and extremely basic sodium hydroxide. Inductively coupled optical emission spectrometry (ICP-OES)/plasma mass spectrometry (ICP-MS), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis (EDX), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) showed that only the sulfuric acid solution 18 M was able to completely dissolve the sample. In addition, chemical analysis allowed to recognize the contact between bone and substances. Hydrated calcium sulfate arose from extreme pH. The possibility of detecting the presence of human material within the residual solution was demonstrated, especially with FT-IR, ICP-OES, and EDX.

Enthalpies of Formation of Layered LiNixMnxCo1-2xO2 Compounds As Promising Li-Ion Battery Cathode Materials

Layer structured lithium mixed transition metal oxides with the general formula of LiNixMnyCozO2 (x+y+z=1) and theoretical capacity of approximately 280 mAh/g are considered as promising intercalation type positive electrode materials for Lithium-ion batteries. Owing to their lower costs and higher capacities, LiNixMnyCozO2 (NMCs) are extensively investigated for electric vehicles and grid storage applications as suitable substitutes for LiCoO2, the most widely used cathode material for Li-ion batteries. Several studies have been devoted to investigating the structure and electrochemical behavior of different compositions in the LiNixMnxCo1-2xO2 (0≤x≤0.5) solid solution series. However, there are very limited thermochemical data reported on these compounds. The enthalpies of formation of LiNi1−xCoxO2 compounds were determined by Wang et al. [1] using high temperature oxide solution calorimetry and the enthalpy of formation of LiNi1/3Mn1/3Co1/3O2 and its delithiated phases were measured by Idemoto et al. [2] using acid solution calorimetry. The aim of this work is therefore to determine the enthalpy of formation of selected compositions in LiNixMnxCo1-2xO2(0≤x≤0.5) series by calorimetric measurements in order to study the relative thermodynamic stabilities of these phases and further clarify structure–property relationships in these compounds. In this study, single phase LiNixMnxCo1-2xO2 for x=1/6, 1/3, 0.4, 0.5 were synthesized according to the sol-gel method using metal acetates and adipic acid as a chelating agent. The chemical compositions of the samples after the final heat treatment were measured by inductively coupled optical emission spectroscopy (ICP-OES). In addition, powder X-ray diffraction (XRD) was performed to determine phase impurities and lattice parameters of the respective compounds. Subsequently, the standard enthalpies of formation of the compounds were measured by employing high temperature oxide melt drop solution calorimetry using a Setaram AlexSys-1000 Tian–Calvet calorimeter (Setaram Instrumentation, Caluire-et-Cuire, France) with a sodium molybdate (3Na2O.4MoO3) solvent maintained at approximately 700°C. The powder-XRD results show that all compositions were single phase adopting the α-NaFeO2 type structure (space group: , No. 166). As x in LiNixMnxCo1-2xO2 increases, the a and c lattice parameters increase whereas the c/a ratio decreases. This can be explained by the difference in ionic radii between Ni2+ and Co3+ and the fact that Co3+ which is situated on the transition metal layer is continuously substituted by equal amounts of Mn4+ and Ni2+. The results of our high temperature oxide melt solution calorimetry measurements show that the standard enthalpies of formation of the LiNixMnxCo1-2xO2 compounds from the elements become more exothermic with increasing x. Therefore, contrary to the work of Idemoto et at. [2], we show that the investigated NMC compounds are energetically more stable than LiCoO2. The increasing thermodynamic stability is caused by the substitution of Co3+ with equal amounts of Mn4+ and Ni2+cations on the transition metal layer (3b sites). Keyword: Lithium nickel manganese cobalt oxide, Layered structure, Oxide solution calorimetry, Enthalpy of formation, Lithium-ion battery References Wang, M. & Navrotsky, A. Enthalpy of formation of LiNiO2, LiCoO2 and their solid solution, LiNi1-xCoxO2. Solid State Ionics 166 (2004), 167-173.Idemoto, Y., & Matsui, T. Thermodynamic stability, crystal structure, and cathodic performance of Lix(Mn1/3Co1/3Ni1/3)O2 depend on the synthetic process and Li content. Solid State Ionics 179 (2008), 625-635.

EH-pH- and main element analyses of Blast Furnace Slag Cement paste pore solutions activated with sodium monofluorophosphate – Implications for carbonation and self-healing

Over the past decade, sodium monofluorophosphate (Na-MFP) gained attention as inorganic self-healing agent on Blast Furnace Slag Cement (BFSC) products. Recent experimental studies revealed the recovering effect of Na-MFP on the microstructure of carbonated BFSC pastes with respect to their frost-salt scaling durability.This study investigates the interactions between pore solution and hydration products of OPC and BFSC pastes that were carbonated and/or vacuum-impregnated with aqueous Na-MFP. Pore solutions of pastes were characterized through systematic EH-pH- and main element analyses by inductively coupled optical emission spectrometry (ICP-OES). Solid hydration products were analyzed by X-ray powder diffraction (XRD).Results indicate that the impregnation of hardened carbonated cement pastes with aqueous Na-MFP results in a recovery of the initial pH of 98.85% and 79.81%, respectively. Analytical results give insight into hydration and carbonation under the influence of Na-MFP. Results are compared with literature and expose that the hypothesis of crystalline apatite formation in BFSC products must be revised.

Study on the Characteristics of ICP-PECVD Boron Silicate Glasses Dependent on Diborane Flux

Boron silicate glasses from inductively-coupled plasma-enhanced chemical vapor deposition are investigated by variation of the diborane flux applied during deposition. Fast Fourier transform infrared spectroscopy measurements of B related peaks calibrated by inductively-coupled optical emission spectroscopy is used to determine the B concentration in the deposited films. Optical, chemical, and electric properties of the boron silicate glasses before and after a high temperature step, as well as of the resulting emitter layer, are discussed. Changes in the molecular composition of the B related bonding structure of the films during the high temperature step are found to be responsible for the properties of the emitter layers as well as the boron silicate glass films. Three corresponding regimes of the film growth depending on the diborane flux are identified and characterized. The formation of a boron-rich layer (BRL) is indirectly shown to be the limiting factor for emitter functions and influencing the corresponding properties under given conditions, i.e., at higher diborane fluxes.

Effect of Surface Charge and Elemental Composition on the Swelling and Delamination of Montmorillonite Nanoclays Using Sedimentation Field-flow Fractionation and Mass Spectroscopy

AbstractThe swelling properties of smectite-type clay particles (including montmorillonite) are of interest in various industries. A fundamental understanding of the surface properties of smectite particles at the sub-micron level would facilitate investigation of the effect of distributed properties such as charge and elemental composition. Swelling and delamination of SWy-2 Na-montmorillonite (Na-Mnt) nano-clay particles were studied here using size distributions obtained by sedimentation field-flow fractionation (SdFFF). Fractions were examined by electron microscopy and inductively-coupled optical emission spectroscopy (ICP-OES). Two distinct populations were observed in the size distribution of SWy-2 Na-Mnt particles (bimodal size distribution), with mean equivalent spherical diameters of ~60 nm and 250 nm, respectively. In contrast, the size distribution of STx-1 Ca-montmorillonite (Ca-Mnt) particles showed only one peak with a mean equivalent spherical diameter of ~410 nm, which changed to 440 nm after 4 days of hydration. Analyses of the fractions by ICP-OES obtained along the size distribution of Na-Mnt showed an abundance of Ca and Mg in the fractions below 250 nm, and confirmed the presence of Fe and Mg as isomorphous substituents. Electron micrographs of the fractions obtained from Na-Mnt size distributions were used to calculate the thickness of the clay particles. Bridging forces between pure orMgsubstituted montmorillonite and either Ca2+ or Na+ were calculated using semi-empirical methods. The results demonstrated that swelling and delamination of Na-Mnt clay particles are dictated by properties such as elemental composition and surface charge which are distributed along the size distribution.

Hierarchical Bimodal Mesoporous Structure Modified with Ni Nanoparticles through One-Pot Process for Effective Carbon Dioxide Methanation

Abstract With the intent of preparing a catalyst support, a hierarchical bimodal mesoporous structure with two types of mesopores (2–50 nm) that would show both high mass transport and high reaction rate was fabricated through a one-pot process using organic monoliths and surfactant micelles. The selectivity and efficiency of a prototypical carbon dioxide (CO2) reduction reaction, namely, the methanation of CO2 on Ni nanoparticles, were increased by the fabricated structure. This catalytic phenomena was discussed using field-emission scanning electron microscopy (FE-SEM), high-angle annular dark-field imaging scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS), N2 adsorption–desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and inductively coupled optical emission spectrometry (ICP-OES), to observe surface area of the structures, catalyst amount, molecular diffusion efficiency, and CO2 methanation mechanisms. The thermal stability of this hierarchical porous structure in the 823–1273 K temperature range was also examined. Although additional experiments such as the change of the pore size, pore shapes, and the ratio of the larger pores and smaller pores, are required to further discussions, there is a possibility that the hierarchical bimodal mesoporous structure can be a good catalyst support.

Siderophile elements in chondrules of CV chondrites

New bulk compositional data for 34 Allende chondrules are presented. Whole chondrules were analyzed by instrumental neutron activation analysis (INAA). The new data set is evaluated together with older INAA data on Allende chondrules and recent INAA data on Mokoia chondrules. The Ni/Co ratios of 200 chondrules are close to the CI- or solar ratio. The chondritic Ni/Co ratios require an unfractionated chondritic metal source and set a limit to the fraction of metal lost from molten chondrules. The bulk chondrule Fe/Ni and Fe/Co ratios are more variable but on average chondritic. Iridium and other refractory metals have extremely variable concentrations in chondrules. High Ir chondrules have chondritic Ir/Sc ratios. They are dominated by CAI (Ca,Al-rich inclusion) components. Low Ir chondrules have approximately chondritic Ir/Ni ratios reflecting mixing with chondritic metal. In low Ir chondrules Ir correlates and in high Ir chondrules Ir does not correlate with Ni or Co. A large fraction of Ir may have entered chondrules in variable amounts as tiny grains of refractory metal alloys.Most Allende chondrules have Ir/Sc ratios below bulk meteorite ratios. Matrix must have a complementary high Ir/Sc ratio, as bulk Allende has approximately chondritic Ir/Sc ratio. Similarly, the high average Ir/Ni ratios of Allende chondrules must be balanced by low Ir/Ni ratios in matrix to obtain the bulk Allende Ir/Ni ratio, which is close to the average solar system ratio.More recent data on single chondrules from Allende by ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and ICP-OES (Inductively Coupled Optical Emission Spectrometry) show the same trends as the INAA data discussed here.

Investigation of Borohydride Oxidation on Graphene Supported Gold-Copper Nanocomposites

Graphene as catalyst support has incurred intense interest in fuel cell applications due to its unique, outstanding physicochemical properties. Pure gold and gold-based catalysts show an enhanced electrocatalytic activity towards the direct oxidation of borohydride. Combination of graphene and gold-based catalysts allows reducing the amount of noble metal and fabricating novel materials with high efficiency towards borohydride electro-oxidation.In this study the graphene supported AuCu catalysts (denoted as AuCu/GR) with different Au:Cu molar ratio were prepared by microwave heating of Au(III) and Cu(II) salts in ethylene glycol (EG) solutions at 150 oC for 30 min. It has been determined that the composition of AuCu/GR catalysts depends on pH of reaction mixture. When the reaction mixture pH was 7.0, 10.1 and 12.2, the AuCu/GR catalysts having the Au:Cu molar ratio 37:1, 1:13 and 1:32, respectively, were synthesized. The morphology, structure and composition of the prepared catalysts were examined by transmission electron microscopy (TEM), X-ray diffraction (XRD) and inductively coupled optical emission spectroscopy (ICP-OES). The electrocatalytic activity of the synthesized catalysts was investigated towards the oxidation of borohydride by means of cyclic voltammetry and chronoamperometry.It was found that Au nanoparticles were successively deposited onto the surface of graphene nanosheets. Au nanoparticles were uniform and well dispersed on the surface of graphene. The analysis of composition of the prepared AuCu/GR catalysts by means of ICP-OES confirms the presence of Au and Cu.The Au loadings were 0.055 mg Au cm–2 in the Au/GR and 0.107, 0.091 and 0.088 mg Au cm–2 in the synthesized AuCu/GR catalysts having the Au:Cu molar ratio 37:7, 1:13 and 1:32, respectively. It has been determined that the graphene supported AuCu catalysts show an enhanced electrocatalytic activity towards the oxidation of BH4 – ions comparing with the graphene supported bare Au catalyst and graphene supported bare Cu catalyst. Furthermore, borohydride oxidation current densities at the graphene supported AuCu/GR catalysts having the Au:Cu molar ratio 1:12 and 1:32 are ~13 times higher than those obtained at the AuCu/GR catalyst with the Au:Cu molar ratio 37:1. Acknowledgement This research was funded by a Grant (No. ATE-08/2012) from the Research Council of Lithuania.

Comparative cytotoxicity of cadmium forms (CdCl2, CdO, CdS micro- and nanoparticles) in renal cells

Cadmium (Cd) is a potent selective toxicant that preferentially accumulates in the kidneys where it is known to induce cellular injury. The cellular mechanisms explaining toxicity have been well documented by in vivo and in vitro studies. However, experiments have mainly been performed on cadmium chloride (CdCl2), while several other forms, such as cadmium oxide (CdO) and cadmium sulfide (CdS), are of interest regarding occupational exposure. CdS is mainly used in nanotechnology, primarily to construct particles known as quantum dots (QDs). The present study focuses on cadmium forms that differ compared to their solubility and their particle size (CdS micro- and uncoated nanoparticles (NPs)), and investigates their effects on mesangial and proximal tubular kidney cells. Cellular toxicity was evaluated by using Neutral Red, MTT and WST-1 assays. Intracellular Cd content was measured using inductively coupled optical emission spectrometry (ICP-OES) and cellular stress was investigated via the effects of Cd complexing bioligands using size exclusion chromatography ICP-MS (SEC-ICP-MS). Data indicated the variability of cytotoxicity responses after CdCl2, CdO, and CdS exposure that were strongly correlated to the cellular Cd content. Release of Cd2+ linked to solubility and particle degradation were considered to be the cause of these toxicities. The bioinduction of the Cd–MT also evidenced release of Cd2+. Our in vitro data identified heterogeneity of Cd toxicity that was dependent on the physico-chemical properties of the form studied and, when considering particle size, constitute an additional step toward the determination of nanoparticle effects in renal cells.

Cisplatin@US-tube carbon nanocapsules for enhanced chemotherapeutic delivery

The use of chemotherapeutic drugs in cancer therapy is often limited by problems with administration such as insolubility, inefficient biodistribution, lack of selectivity, and inability of the drug to cross cellular barriers. To overcome these limitations, various types of drug delivery systems have been explored, and recently, carbon nanotube (CNT) materials have also garnered attention in the area of drug delivery. In this study, we describe the preparation, characterization, and in vitro testing of a new ultra-short single-walled carbon nanotube (US-tube)-based drug delivery system for the treatment of cancer. In particular, the encapsulation of cisplatin (CDDP), a widely-used anticancer drug, within US-tubes has been achieved, and the resulting CDDP@US-tube material characterized by high-resolution transmission electron microscopy (HR-TEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and inductively-coupled optical emission spectrometry (ICP-OES). Dialysis studies performed in phosphate-buffered saline (PBS) at 37 °C have demonstrated that CDDP release from CDDP@US-tubes can be controlled (retarded) by wrapping the CDDP@US-tubes with Pluronic-F108 surfactant. Finally, the anticancer activity of pluronic-wrapped CDDP@US-tubes has been evaluated against two different breast cancer cell lines, MCF-7 and MDA-MB-231, and found to exhibit enhanced cytotoxicity over free CDDP after 24 h. These studies have laid the foundation for developing US-tube-based delivery of chemotherapeutics, with drug release mainly limited to within cancer cells only.