Energy Dispersive X-ray Microanalysis System Research Articles

Brazilian Coal Tailings Projects: Advanced Study of Sustainable Using FIB-SEM and HR-TEM

The objective of this study is to obtain a more detailed assessment of particles that contain rare-earth elements (REEs) in abandoned deposits of Brazilian fine coal tailings (BFCTs), so as to aid current coal mining industries in the identification of methodologies for extracting such elements (Santa Catarina State, Brazil). The BFCT areas were sampled for traditional mineralogical analysis by X-ray Diffraction, Raman Spectroscopy and nanomineralogy by a dual beam focused ion beam (FIB) coupled with field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) coupled with an energy dispersive X-ray microanalysis system (EDS). The results show that the smaller the sampled coal fines were, the higher the proportion of rare-earth elements they contained. Although the concentration of REEs is below what would normally be considered an economic grade, the fact that these deposits are already ground and close to the surface negate the need for mining (only uncovering). This makes it significantly easier for REEs to be extracted. In addition, owing to their proximity to road and rail transport in the regions under study, the opportunity exists for such resources (BFCTs) to be utilized as a secondary market as opposed to simply being discarded as has been done in the past.

Correlation between chemical composition of enamel and oral fluid in patients with intact teeth and cervical pathology

Annotation. Cervical pathology of teeth is widespread and polyetiological, saliva plays an important role in its occurrence and progression. The aim of the study is to determine the chemical composition of oral fluid in patients with cervical caries, wedge-shaped defect, intact hard dental tissues; establish correlations between oral fluid and cervical enamel. In this regard 33 patients were divided depending on the condition of hard dental tissues and there were determined: Сa2+, РО43-, SO42-, Na+, К+, Al3+, Mg2+, Zn2+ – by spectrometric methods, Cl- – using a chloride-selective electrode pH-meter. The chemical composition of cervical enamel of 29 removed intact teeth and with cervical pathology was studied using a scanning electron microscope JSM-6490 LV with energy-dispersive X-ray microanalysis system INCA Penta FETx3. Molar coefficients were calculated as the ratio of the number of chemical analytes in the supernatant. Statistical analysis was performed using the computer program Statistica 8.0 (STA862D175437Q). Applied: analysis of variance (Welch test), correlation analysis (Pearson's parametric correlation method) based on the determination of the parametric Brave-Pearson coefficient (r) at p<95%. The reliability of the obtained results was evaluated by Student's t-test and by Student's test using the Z-test (Fisher's z-test) at p≤0.05. There was no significant difference in the amount of chemical elements in saliva between the groups (p>0.05) and significant differences were determined in K/Na (p=0.0258). There was correlation between chemical analyte content in the oral fluid and cervical tooth enamel: direct ‑ between Са2+ and РО43-, К+ and Cl-, К+ and Na+; inverse – between Са2+ and К+, Са2+ and Cl-, РО43- and К+, РО43- and Cl- (p<0.0001). Correlation was identified: direct – between Ca/P and Ca/Mg, Ca/P and Ca/Cl, P/Ca and K/Na, Mg/Ca and Mg/P; inverse -‑between K/Na and Ca/P, K/Na and Ca/Cl, P/Ca and Ca/Cl, P/Ca and Ca/P (p≤0.05). Obtained results allowed to use Ca/Mg ratio as an indicator of enamel mineralization. We propose to use certain differences in correlation of chemical elements of oral fluid and tooth enamel to assess the mineral state of tooth enamel and control the effectiveness of preventive measures. Based on saliva parameters and microbiological indicators of dental biofilm the search for ways of preclinical diagnosis of cervical pathology is promising.

Nanoparticles and interfaces with toxic elements in fluvial suspended sediment

Studies examining nanoparticles (NPs) and hazardous elements (HEs) contained in suspended sediments (SSs) are vital for watershed administration and ecological impact evaluation. The biochemical consequence of titanium-nanoparticles (Ti-NPs) from SSs in Colombia's Magdalena River was examined utilizing an innovative approach involving nanogeochemistry in this study. In general, the toxicity and the human health risk assessment associated with the presence of some Ti-NPs + HEs in SSs from riverine systems need to be determined with a robust analytical procedure. The mode of occurrence of Ti-NPs, total Ti and other elements contained within SSs of the Magdalena River were evaluated through advanced electron microscopy (field emission scanning electron microscope-FE-SEM and high resolution transmission electron microscope-HR-TEM) coupled with an energy dispersive X-ray microanalysis system (EDS); X-Ray Diffractions (XRD); and inductively coupled plasma-mass spectrometry (ICP-MS). This work showed that enormous quantities of Ti-NPs were present in the river studied and that they displayed diverse geochemical properties and posed various possible ecological dangers. Ti-NP contamination indices must be established for measuring the environmental magnitudes of NP contamination and determining contamination rank among rivers. Finally, SS contamination guidelines must be recommended on an international level. This study contributes to the scientific understanding of the relationship of HE and Ti-NP dynamics from SSs in riverine systems around the world.

Physiochemical characterization and toxicity assessment of colloidal mercuric formulation–‘Sivanar amirtham’

The study aims to characterize and understand the toxicological effects of colloidal mercuric formulation. The physiochemical characterization was carried out using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Energy dispersive X-ray microanalysis system (EDS), Inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffraction (XRD), Zeta potential, Brunauer-Emmett-Teller (BET) and electron microscopy. Based on the physiochemical characterizations, the pairwise relationship between the parameters such as size, surface area, surface charge, reactivity and band gap energy were described. The biological effects of the sample were studied by both in vitro and in vivo assays. The in vitro cytotoxicity assay confirmed that the colloidal mercuric formulation was effective against cancer cells (MCF-7) and less toxic to normal cells (Hek 293). The formulation was effective against MCF-7 with more than 85% of apoptotic and necrotic cells, positive for PI staining when treated with 100 μg/mL. The inflammatory response on the macrophage cell lines was studied. The colloidal mercuric formulation upregulated the expression of TGF-β, IL-6 and TNF-α, due to the presence of arsenic and other organic compounds such as piperine. The in vivo developmental toxicity was observed in Zebrafish hampered growth and survival in a dose and time dependent manner. The formulation was safe at lower concentration and exhibit a dose and time dependent toxicity. Based on the results obtained, it is confirmed that the selective toxicity towards MCF-7 cells is promising to develop an effective formulation for the treatment of cancer, provided more such proofs obtained from in vivo experiments.

Titanium nanoparticles in sedimented dust aggregates from urban children’s parks around coal ashes wastes

Recently, an increased interest in nanoscience applications can be observed in various fields. Soils around coal power plants may contain potentially hazardous elements (PHEs) and nanoparticles (NPs), which can be neo-produced pollutants or can be a product of industrial coal utilization. While titanium (Ti)-NPs contact is a worldwide concern, transference of Ti-NPs to infants as well as their human health impact is still imprecise. In general, the toxicity and the human health risk assessment associated with the presence of some Ti-NPs, needs to be determined with a robust and fast analytical methodology. The mode of occurrences of Ti-NPs in children’s playgrounds were evaluated by advanced electron microscopy techniques (field emission scanning electron microscope-FE-SEM and high resolution transmission electron microscope-HR-TEM) coupled with an energy dispersive X-ray microanalysis system (EDS); Raman Spectroscopy (RS); and X-Ray Diffractions (XRD). The reported data showed that when the size of the NPs reduced, the ability of sedimented dust aggregates to transport PHEs increased. Carbonaceous matter and amorphous silica were the main factors that influenced the distribution of PHEs among the studied Ti-NPs aggregates. Together, the data indicate that the proportions of PHEs in sedimented urban dust in the urban area around coal power plants are mainly due to emissions related to vehicle traffic and the coal industry, representing immediate environmental risks and long-term health risks. Therefore, actions are required to monitor and mitigate the impact of Ti-NPs aggregates in the urban area and nearby ecosystems. Such pollutants are necessary to be observed as children represent a susceptible cluster likened to adults. The currently estimated risk can be influenced by factors such as absorption, form of Ti-NPs, particle fraction, particle size, and physico-geochemical properties in relation to toxicity, among others. Analysis of actual particle concentrations in human organs, as well as organ concentrations and effects in liver and the reproductive system after chronic exposure to well-characterized Ti-NPs in animals are recommended to refine this assessment.

Selective zircon accumulation in a new benthic foraminifer, Psammophaga zirconia, sp. nov.

Benthic foraminifera are single-celled eukaryotes that make a protective organic, agglutinated or calcareous test. Some agglutinated, single-chambered taxa, including Psammophaga Arnold, 1982, retain mineral particles in their cytoplasm, but the selective mechanism of accumulation is not clear. Here, we report the ability of a foraminiferal species to select and accumulate zircons and other heavy minerals in their cytoplasm. In particular, the use of Scanning Electron Microscope coupled with an Energy Dispersive X-ray microanalysis system (SEM-EDS) enabled a representative overview of the mineral diversity and showed that the analysed Psammophaga zirconia sp. nov. individuals contained dominantly crystals of zircon (51%), titanium oxides (27%), and ilmenite (11%) along with minor magnetite and other minerals. The studied specimens occur in the shallow central Adriatic Sea where the sediment has a content of zircon below 1% and of other heavy minerals below 4%. For that reason we hypothesize that: (i) P.zirconia may be able to chemically select minerals, specifically zircon and rutile; (ii) the chemical mechanism allowing the selection is based on electrostatic interaction, and it could work also for agglutinated foraminifera (whether for ingestion, like Xenophyophores, or incorporation in the test as in many other described taxa). In particular, this aptitude for high preferential uptake and differential ingestion or retention of zircon is reported here for the first time, together with the selection of other heavy minerals already described in members of the genus Psammophaga. They are generally counted among early foraminifera, constructing a morphologically simple test with a single chamber. Our molecular phylogenetic study confirms that P.zirconia is a new species, genetically distinctive from other Psammophaga, and occurs in the Adriatic as well as in the Black Sea.

Recovering Heavy Metal Ions from Complex Solutions Using Polyethylenimine Derivatives Encapsulated in Alginate Matrix

A new sorbent was manufactured by immobilization of polyethylenimine (PEI) derivatives (glutaraldehyde-cross-linked PEI, and carbon disulfide-grafted PEI) into an alginate matrix. These composite materials take advantage of the sorption properties of both PEI and alginate, and the encapsulating properties of the biopolymer. The sorption properties of these composite materials were tested for the recovery of Cd(II), Cu(II), and Zn(II) ions from aqueous solutions. Kinetic, equilibrium, and desorption behaviors were successively investigated. Special attention was paid to competitive sorption and to the effect of inorganic ions on sorption efficiency. Sorbent morphology was observed using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray microanalysis system (EDX). SEM-EDX results show a homogeneous distribution of heavy metals in beads after metal sorption. Alginate was found to have a better sorption capacity for all heavy metals studied in simple systems. Conversely, calcium an...

Effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate using electron microscopy and energy dispersive X-ray microanalysis.

Aim:To investigate the effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate (MTA) used as a coronal seal material for nonvital bleaching, beneath the bleaching agent, with the help of energy dispersive X-ray microanalysis and scanning electron microscopy (SEM).Materials and Methods:Six samples of plastic tubes filled with white MTA (Angelus white) were kept in 100% humidity for 21 days. Each sample was divided into 2 and made into 12 samples. These were then divided into three groups. Group A was exposed to Opalescence Boost 40% hydrogen peroxide (HP) (Ultradent). Group B to Opalescence 10% carbamide peroxide (Ultradent) and Group C (control group) not exposed to any bleaching agent. After recommended period of exposure to bleaching agents according to manufacturers’ instructions, the samples were observed under SEM with an energy dispersive X-ray microanalysis system (JSM-6380 LA).Results:There were no relevant changes in color and no statistically significant surface structure changes of the MTA in both the experimental groups.Conclusion:The present findings suggest that even high concentration HP containing bleaching agents with neutral pH can be used on the surface of MTA without causing structural changes. The superior sealing ability of MTA and the high alkalinity would prevent cervical resorption postbleaching.

Electromagnetic absorption properties of natural microcrystalline graphite

An effective composite of natural microcrystalline graphite/low density polyethylene (MG/LDPE) was prepared by extrusion calendering method and the electromagnetic absorption properties of the composites were investigated. The morphology and structure of the MG were characterized by scanning electron microscopy, energy-dispersive X-ray microanalysis system, Raman spectroscopy and X-ray diffraction. It is interesting to find that two absorbing peaks appear at low frequency and high frequency with the thickness of 2.0–2.1mm. Results show that the content and the particle size of MG have great effects on the electromagnetic absorption property of the MG/LDPE composites. Under the condition that the speed of ball-milling is 800r/min, the bandwidth of MG/LDPE composites less than −5dB reaches 6.79GHz, its less than −10dB comes to 3.02GHz, and the reflectivity values are −12.44dB and −20.46dB. The remarkable electromagnetic absorption properties of MG/LDPE composite can attribute to the multiple absorbing mechanisms. It is believed that such a composite could serve as an attractive candidate for electromagnetic absorbers.

Environmental Impact Monitoring of a Minero-chemical Complex in Catalão Urban Area of Pts, Pm10 and Pm2.5 by Edx Characterization

Depending on its nature, particulate matter has very different size, composition and morphology. By the combination of these criteria it is possible to distinguish the emitting sources (primary or secondary). The shape and the dimension of the particles have also a direct interaction with the risk assessment for human health. The minero-chemical complex consists of phosphate fertilizer manufacturing, rock phosphate and niobium mining open pits and it is located northeast of the urban area of the city. Environmental issues associated with it include the following: fugitive emissions which are primarily associated with operational leaks from tubing, valves, connections, flanges, packings, open ended lines, floating roof storage tank and pump seals, gas conveyance systems, compressor seals, pressure relief valves, tanks or open its/containments, and loading and unloading operations of products. Furthermore the area of study is characterized by a predominantly northeast winds direction. The monitoring was performed weekly particulates samples were collected in two seasonal episodes at one representative places in the urban area of Catalao (a Brazilian city located in Goias state) in the period from August to November of 2014. Suspended particles were sampled on pure fiberglass filters by using a High Volume air sampler and were analyzed via an energy dispersive X-ray microanalysis system (EDX). The airborne particulate matter was characterized from a physico-chemical point of view to supply information on the particle composition and the compounds carried on their surfaces. The microanalysis enables identification of several groups of particles such as: soot, Si-rich, metal-rich and biological particules. These results may help in controlling and preventing fugitive emissions in atmospheric air.

Biochemical characterization of Macrocystis pyrifera and Undaria pinnatifida (Phaeophyceae) in relation to their potentiality as biosorbents

:Undaria pinnatifida and Macrocystis pyrifera from Patagonia were characterized in terms of the alginate, protein, total carbohydrate and organic matter content, cation exchange capacity and acid-base properties to assess the suitability of both species as potential biosorbents of metals. Environmental scanning electron microscopy equipped with an energy dispersive X-ray microanalysis system, Fourier transform infrared spectroscopy (FT-IR) and Brunauer, Emmett and Teller surface area analysis were also applied for characterization. The results showed that U. pinnatifida had a higher percentage of organic matter, alginate and protein and a larger specific surface area than M. pyrifera, although the latter exhibited a higher ionic exchange capacity. The groups with a weak acid behaviour represented 84% and 97% of the total acid groups in M. pyrifera and U. pinnatifida, respectively. FT-IR analysis confirmed the presence of different chemical groups such as sulphonate in both biomaterial M. pyrifera and U. pinnatifida. Besides, Zn(II) adsorption capacity was different among different parts of the thallus of each species. The difference founded in the physicochemical properties of both algae could affect their biosorption capacities.

Interdisciplinary study on pottery experimentally impregnated with wine

AbstractExperimentally developed ceramic pots, with two different sizes of grain, were half-filled with wine and subjected to thermal alteration at constant elevated temperature ((60 ± 2)°C) in darkness for 12 weeks. This work sought to characterise the samples thereby obtained from chemical and mineralogical perspectives using scanning electron microscopy and an energy-dispersive X-ray microanalysis system (SEM-EDX), Fourier transform infrared spectroscopy (FTIR) and capillary electrophoresis (CE) with UV detection as an alternative to chromatographic methods, due to its good resolution, automation, simplicity, high speed, low consumption of chemicals and short time required for sample preparation. The capillary electrophoresis method was used for the detection of five wine biomarkers: succinic acid, malic acid, tartaric acid, citric acid and lactic acid. In general, it was noted that the fine-grained ceramic assortment retained the organic material better than the coarser-grained ceramics. An interesting observation derived from this study was that not only could tartaric acid be considered as a biomarker for wine residues in archaeological pottery, but malic acid could also act similarly for white wine and lactic acid for red wine.

Subcellular compartmentation of strontium and zinc in mulberry idioblasts in relation to phytoremediation potential

The cellular compartmentation of heavy metals was analyzed using mulberry leaves, in which CaCO3-forming idioblasts are situated in the epidermal layer. Germinated mulberry seedlings were grown on hydroponic culture medium containing strontium (Sr), zinc (Zn), and cadmium (Cd) with and without supplemental calcium (Ca). After ten weeks of growth, toxic effects of these metals were assessed by measuring shoot length and chlorophyll content of leaves. Sr and Cd treatment at a higher dose (4mM for Sr, 25μM for Cd) resulted in signs of toxicity, whereas no distinct phytotoxicity was observed at 500μM Zn. Elemental mapping of leaves using an energy-dispersive X-ray microanalysis system fitted to variable-pressure scanning electron microscope showed that Sr and Zn were preferentially accumulated in the idioblasts and Cd was not detected in any type of leaf cell. The deposition site of Sr was confined to cell wall sacs developing in idioblasts. The Sr sink capacity in leaves was more than 30mg/g dry weight, which equaled the Ca sink capacity. Exposure of Sr+Ca led to the co-localization of Sr and Ca in the same cell wall sac, in which Ca and Sr deposition were each estimated to be 60–80ng. The localization site of Zn was cell walls of a dome-shaped protrusion (cap) of idioblasts, together with silicon (Si) originating as a contaminant in tap water used for culturing. Mulberry idioblasts were unique in showing metal-dependent distribution to two subcellular sites (cell wall sac and cap region) of idioblasts. In conclusion, mulberry plant is a candidate for phytoremediation of radiostrontium because of their Sr-hyperaccumulating capacity with sufficient leaf biomass production.

Cuticular calcium penetration is directly related to the area covered by calcium within droplet spread area

Calcium penetration from salt solutions of calcium chloride and calcium acetate was measured through isolated tomato fruit ( Solanum lycopersicum L., cultivar ‘Panovy’) cuticles after 4, 24, and 48 h. Droplet spread area (volume = 1 μL) and the area ultimately covered with calcium were determined with a scanning electron microscope which has an integrated energy dispersive X-ray microanalysis system. An ethoxylated rapeseed oil surfactant (RSO 5) was used for inducing different degrees of droplet spread and together with different calcium concentrations of the solutions to vary the concentration gradient in the penetration experiments. As a rule, penetration of calcium from CaCl 2 was higher than that of Ca(CH 3COO) 2. The addition of RSO 5 to salt solutions resulted in enhanced calcium penetration in comparison to unformulated solutions. However, extending penetration time from 4 to 48 h predominantly did not enhance the penetrated calcium amount significantly. Droplet spread area was enhanced up to 4-fold after adding RSO 5, whereas the area ultimately covered with calcium did not exceed twice as much. This resulted in lower percentage area covered by calcium in droplet footprints from formulated solutions in comparison to solutions without addition of RSO 5. Correlation analyses showed that penetration was not related to droplet spread area but significantly correlated with the area covered by calcium. These observations were true for unformulated calcium salts as well as for calcium solutions with addition of RSO 5. Therefore, the area ultimately covered with calcium or even other xenobiotics within a droplet footprint should be considered in developing mathematical models to simulate active ingredient (a.i.) penetration.

Highly Photoconductive Copper Phthalocyanine-coated Titania Nanoarrays via Secondary Deposition

Based on an anodic aluminum oxide template, a sol−gel dip-coating technique and electrophoretic deposition processes were combined to fabricate TiO 2 nanowire arrays, copper phthalocyanine (CuPc) nanowire arrays, and CuPc-coated TiO 2 nanowire (CuPc/TiO 2 NW) arrays. The resulting nanostructures were characterized by field-emission scanning electron microscope, energy dispersive X-ray microanalysis system, X-ray diffraction patterns, and time-resolved fluorescence spectra. A series of dual-layered photoreceptors containing the above three kinds of nanowire arrays as the charge generation layer (CGL) were designed and fabricated. Their photoconductivities under illumination of visible light were investigated using a photoinduced xerographic discharge technique. It was found that the photoreceptor based on CuPc/TiO 2 NW arrays as CGL exhibited 1 order of magnitude higher photoconductivity than that of pristine TiO 2 or CuPc nanowire arrays due to the large donor−acceptor (CuPc-TiO 2) contact area and the di...

Synthesis and catalytic properties of amorphous Ni–P alloy hollow microspheres

Abstract Amorphous Ni–P hollow microspheres have been synthesized on a large scale by using a template method via electroless deposition. Hollow glass microspheres were used as templates. Field-emission scanning electron microscopy, energy dispersive X-ray microanalysis system and X-ray powder diffraction were used to characterize such hollow microspheres. The liquid-phase nitrobenzene hydrogenation was used as a probe reaction to evaluate the catalytic activity of the obtained hollow microspheres. And the result shows that the amorphous Ni–P alloy hollow microspheres exhibit higher catalytic activity and stability than Raney-Ni catalysts.

Characterisation of aerosol from Santiago, Chile: an integrated PIXE–SEM–EDX study

Santiago de Chile is a big city with huge air quality problems, being one of the most polluted cities in the world. This is aggravated during winter by the topography and meteorological conditions of the city. Although public policies have been developed to minimise the atmospheric aerosol pollution, there is a lack of adequate knowledge and poor characterisation of these aerosols (in its PM2.5 and PM10 fractions). In this study we sampled atmospheric particles during winter in two distinct areas of Santiago: downtown (Teatinos Street) and in a more residential area (Macul). Major (Si, Al, Fe, Ca and K) and some trace element (S, Cl, Ti, P, Cr, Cu and Zn) compositions were obtained by proton-induced X-ray emission (PIXE). Morphological, type and chemical characterisation was also performed using scanning electron microscopy (SEM) coupled with an energy dispersive X-ray microanalysis system (SEM–EDX). Besides the carbon particles, the contribution of which can be quite important in the atmospheric aerosol, especially in downtown, unambiguously lithogenic (i.e. of geological origin) particles and elements are the second highest contributors. Enrichment factor calculation, together with particle identification and element correlation allow the origin of some elements and particles to be traced, revealing anthropogenic origins for some of them that are specific to the Santiago area.

Variations in the source, metal content and bioreactivity of technogenic aerosols: a case study from Port Talbot, Wales, UK

Atmospheric aerosol samples were collected during different prevailing wind directions from a site located close to a busy motorway, a major steelworks, and the town of Port Talbot (Wales, UK). A high-volume collector was used (1100 l/min), enabling relatively large amounts of particulate matter (PM 10–2.5 and PM 2.5) samples to be obtained on a polyurethane foam [PUF, H 2N–C(O)O–CH 2CH 3] substrate over periods of 2–7 days. Four samples were chosen to exemplify different particle mixtures: SE- and NE-derived samples for particles moving along and across the motorway, a NW-derived sample from the town, and a mixed SW/SE-derived sample containing a mixture of particles from both steelworks and motorway. The latter sample showed the highest average collection rate (0.9 mg/h, 13 μg/m 3) and included a prominent pollution episode when rainy winds were blowing from the direction of the steelworks. Both NW and SE samples were collected under dry conditions and show the same collection rate (0.7 mg/h, 10 μg/m 3), whereas the NE sample was collected during wetter weather and shows the lowest rate (0.3 mg/h, 5 μg/m 3). Scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis system (EDX) analyses show all samples are dominated by elemental and organic carbon compounds (EOCC) and nitrates, with lesser amounts of sulphates, felsic silicates, chlorides and metals. ICP–MS analyses show the SW/SE sample to be richest in metals, especially Fe, Zn, Ni, and Mn, these being attributed to an origin from the steelworks. The SE sample, blown along the motorway corridor, shows enhanced levels of Pb, V, Ti, As, and Ce, these metals being interpreted as defining a traffic-related chemical fingerprint. The NW sample shows a very low metal content. DNA plasmid assay data on the samples show TM 50 values varying from 66 to 175 μg/ml for the adjusted whole sample and 89 to 203 μg/ml for the soluble fraction. The SW/SE-mixed metalliferous sample is the most bioreactive (both whole and soluble) and the soluble fraction of the metal-depleted NW sample is the least bioreactive. The metal content of the aerosol samples, especially soluble metals such as Zn, is suggested to be the primary component responsible for oxidative damage of the DNA, and therefore most implicated in any health effects arising from the inhalation of these particulate cocktails.

Synthesis of nanocrystalline/quasicrystalline Mg32(Al,Zn)49by melt spinning and mechanical milling

In the present investigation we have made an attempt to synthesize T-Mg32(Al,Zn)49 Frank Kasper phase and investigate the mechanical properties of the T-Phase in micro and nano scale. Single T-Phase (bcc, a = 1.42 nm) has been prepared by conventional casting with a proper combination of flux in order to avoid the loss of magnesium from the melt. Chemical analysis by energy dispersive X-ray microanalysis system attached to scanning electron microscope has confirmed the desired composition for T-phase. The as-cast material was then rapidly solidified by melt spinning and mechanically milled using a high-energy ball mill. The samples were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. The rapidly solidified foils showed the presence of mostly nanoquasicrystalline phases coexisting with a minute amount of crystalline phases in the thin region where the cooling rate is expected to be high. The dark field imaging in electron microscopy clearly confirms the existence of nano phases. Mechanically milled powder exhibited the evolution of nanophases at higher milling time. Microhardness measurement at low load was carried out in both the as-cast and nanophase materials in order to understand the influence of nanophases on the mode of deformation and cracking at low load.

X-RAY MICROANALYSIS OF APPLES TREATED WITH KAOLIN INDICATES WAX-EMBEDDED PARTICULATE IN THE CUTICLE

Gala' apples trees were treated with kaolin (Surround) in mid-July, and fruit were sampled 1 and 7 days after treatment. Apples were gently rinsed with cold deionized water to remove loose surface material. Small sections of cuticle tissue were shaved from the fruit surface with a razor blade and flash frozen on an aluminum block held at -190oC with liquid N2. The tissue was freeze-dried, coated with a thin film of carbon, and examined using a field emission scanning electron microscope coupled with an energy dispersive x-ray microanalysis system capable of light element detection. Qualitative secondary electron imaging combined with quantitative elemental compositional analyses indicated kaolin particles may become embedded in the cuticle between individual wax platelets. INTRODUCTION Sun-induced injury (solar injury, SI) can be a costly problem in some years for tree fruit growers, especially in hot, arid regions. Although the injury to the fruit appears to be a combination of heat and solar radiation exposure (Lipton and O’Grady, 1980), synergistic thresholds for temperature, and radiation wavelength and intensity have not been clearly defined. To reduce this type of injury, therefore, either temperature or radiation, or both, must be reduced or regulated. Lipton and Matoba (1971) reduced the surface temperature of ‘Crenshaw’ melons (Cucumis melo, L.) by as much as 8 °C by applying a mineral whitewash material to the fruit surface, and thus reduced SI damage. Lipton (1972) also demonstrated that mineral whitewash applied to the melon fruit surface reduced internal tissue temperature and, as a result, improved fruit quality. (Mineral whitewash contains kaolinite, bentonite, attapulgite, as well as spreading and sticking agents). More recently, Glenn et al. (2002) reported kaolin alone reduced solar injury to apple fruit. Kaolin, also known as kaolinite, is a clay mineral with the chemical composition Al 4(OH)5O2Si2. The basic building blocks are layers of silica tetrahedra and layers of alumina octahedra in a 1:1 relationship. The unit cell repeats in the x and y direction to form extensive sheets in the xy plane, and in the z direction to form stacks of sheets (Barak and Nater, 2002). When placed in water the platelets shift apart, each plate attracting water to its negative face. Kaolin particulate may absorb 7 to 10 times its own weight, consequently swelling up to 18 times its dry volume. Because of these characteristics, we wanted to know first, whether small particles would lodge in the micro-cracks of the fruit cuticle surface, second, whether the particles would become an integral part of the cuticle as the micro-cracks continued to ‘heal’ with new growth of wax platelet, and third, because of the marketability of appearance, whether the integration of clay particles within the cuticle matrix would alter the properties of the cuticle itself. MATERIALS AND METHODS Mature 'Gala'/EMLA MM.106 apples trees in northcentral Washington were treated with a single application of kaolin (Surround) in mid-July. Fruit were sampled 1 and 7 days after treatment, placed in a cooler held at 34oC and transported to the Proc. XXVI IHC – Deciduous Fruit and Nut Trees