14 research outputs found

    Method Development Using Laser Ablation And Solution Icpms And Their Application In Environmental Science And Forensic Provenance Studies

    Get PDF
    Inductively coupled plasma mass spectrometry (ICPMS) is an analytical technique that can be used to determine multiple elements and isotope ratios in a wide variety of samples. In this work, four projects are described that involve the method development using laser ablation (LA) and solution-based ICPMS and their application in environmental science and forensic (provenance) investigations. In the first project, plutonium (Pu) concentrations and 240Pu/ 239Pu atom ratios were measured in kelp, lichen, aquatic moss, and horse mussel collected on or near Amchitka Island, a former nuclear test in Alaska, and at a background site. The Pu in terrestrial and freshwater species had 240Pu/239Pu ratio signatures typical of northern hemisphere atmospheric fallout, whereas Pu ratios in marine species were elevated, which is characteristic of the northern Pacific Ocean. Potential sources of Pu to the marine species were identified, with high-yield tests conducted in the Marshall Islands being the most likely of these sources. The second project used LA-ICPMS for sourcing iron-rich pigments used in ancient pictographs in the Pecos River Archeological Region. Potential pigment materials (siltstone, ochre, quartzite, and rhyolite) were analyzed for elemental signatures and were compared to rock paint using multivariate statistics. Siltstone was identified as the most probable raw material used in the production of the paint. A pigment cake from near cave site 41VV74 was determined to have similar elemental patterns to siltstone. The third project studied the effect of glyphosate herbicide on the mineral levels in glyphosate-resistent (GR) soybeans. Results from both greenhouse and field studies shono statistical difference in mineral concentrations between glyphosate-treated soybean and the control. This work supports the claim that application of glyphosate should have no significant impact on mineral concentrations in GR soybeans. In the fourth project, a new analytical method using LA-ICPMS was developed for the rapid determination of select dietary minerals and trace elements in commercial herbal supplement capsules. The analytical results were comparable to that using conventional solution-nebulization ICPMS. Chemometrics was successfully applied to discriminate the different manufacturers of the same herbal supplements according to the chemical signatures

    Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Analysis of Lower Pecos Rock Paints and Possible Pigment Sources

    Get PDF
    Chemical analyses of prehistoric rock paints from the Lower Pecos Region of southwestern Texas were undertaken using laser ablation-inductively coupled plasma-mass spectrometry. This technique allowed us to measure the chemical composition of the paint pigments with minimal interference from a natural rock coating that completely covers the ancient paints. We also analyzed samples representing potential sources of paint pigments, including iron-rich sandstones and quartzite from the study area and ten ochre samples from Arizona. Cluster analysis, principle component analysis and bivariate plots were used to compare the chemical compositions of the paint and pigment sources. The results indicate that limonite extracted from the sandstone was the most likely source for some of the pigments, while ochre was probably used as well

    Seasonal Dispersal of Fjord Meltwaters as an Important Source of Iron and Manganese to Coastal Antarctic Phytoplankton

    Get PDF
    Glacial meltwater from the western Antarctic Ice Sheet is hypothesized to be an important source of cryospheric iron, fertilizing the Southern Ocean, yet its trace-metal composition and factors that control its dispersal remain poorly constrained. Here we characterize meltwater iron sources in a heavily glaciated western Antarctic Peninsula (WAP) fjord. Using dissolved and particulate ratios of manganese to iron in meltwaters, porewaters, and seawater, we show that surface glacial melt and subglacial plumes contribute to the seasonal cycle of iron and manganese within a fjord still relatively unaffected by climate-change-induced glacial retreat. Organic ligands derived from the phytoplankton bloom and the glaciers bind dissolved iron and facilitate the solubilization of particulate iron downstream. Using a numerical model, we show that buoyant plumes generated by outflow from the subglacial hydrologic system, enriched in labile particulate trace metals derived from a chemically modified crustal source, can supply iron to the fjord euphotic zone through vertical mixing. We also show that prolonged katabatic wind events enhance export of meltwater out of the fjord. Thus, we identify an important atmosphere–ice–ocean coupling intimately tied to coastal iron biogeochemistry and primary productivity along the WAP

    Geochemical Characteristics of Soils on Ellis Island, New York-New Jersey, Sixty Years after the Abandonment of the Hospital Complex

    No full text
    Soil plays many critical roles in ecosystem health. As urbanization expands into once industrial and commercial lands, there is increased potential for human exposure to soil contaminants, including heavy metals introduced by past anthropogenic activities. Thus, it is important to assess soil contamination in such areas for public health concerns. In this study, we investigated the physico-chemical characteristics of soils from an abandoned hospital complex on Ellis Island, New York (NY) – New Jersey (NJ) to assess the geochemical conditions of the local soil environment and metal contamination from historical activities, including coal-burning and use of lead arsenate insecticide and lead paint. The soil texture, nutrient content and heavy metal (As, Pb, Cr, Cd, Cu and Hg) concentrations were determined and their impact was evaluated. Soils were mostly sandy loam with C:N ratios of about 20:1. Heavy metals were elevated compared to background soils. Concentrations of acid extractable As and Pb ranged from 8.12 to 26.3 mg·kg−1 and 257 to 1008 mg·kg−1, respectively. Total-Hg concentrations varied from 0.191 to 0.899 mg·kg−1, with the higher levels likely from local coal-burning and deposition from the prevailing westerly winds. Overall, we find that even after 60 years of abandonment, the impact to Ellis Island soil from past human activities can still be observed

    PKD2/polycystin-2 inhibits LPS-induced acute lung injury in vitro and in vivo by activating autophagy

    No full text
    Abstract Polycystin-2 (PC2), which is a transmembrane protein encoded by the PKD2 gene, plays an important role in kidney disease, but its role in lipopolysaccharide (LPS)-induced acute lung injury (ALI) is unclear. We overexpressed PKD2 in lung epithelial cells in vitro and in vivo and examined the role of PKD2 in the inflammatory response induced by LPS in vitro and in vivo. Overexpression of PKD2 significantly decreased production of the inflammatory factors TNF-α, IL-1β, and IL-6 in LPS-treated lung epithelial cells. Moreover, pretreatment with 3-methyladenine (3-MA), an autophagy inhibitor, reversed the inhibitory effect of PKD2 overexpression on the secretion of inflammatory factors in LPS-treated lung epithelial cells. We further demonstrated that overexpression of PKD2 could inhibit LPS-induced downregulation of the LC3BII protein levels and upregulation of SQSTM1/P62 protein levels in lung epithelial cells. Moreover, we found that LPS-induced changes in the lung wet/dry (W/D) weight ratio and levels of the inflammatory cytokines TNF-α, IL-6 and IL-1β in the lung tissue were significantly decreased in mice whose alveolar epithelial cells overexpressed PKD2. However, the protective effects of PKD2 overexpression against LPS-induced ALI were reversed by 3-MA pretreatment. Our study suggests that overexpression of PKD2 in the epithelium may alleviate LPS-induced ALI by activating autophagy

    Simultaneous Determination of I/Ca and Other Elemental Ratios in Foraminifera: Comparing Results From Acidic and Basic Solutions

    No full text
    Abstract The iodine to calcium ratio in carbonate (I/Ca) has been widely used to indicate ocean oxygenation level in the past. Given the volatility of iodine, I/Ca has been measured in alkaline solutions in previous studies. However, this limits the application of I/Ca with other element/Ca (El/Ca) proxies at the same time and in the same foraminifera because other El/Ca data are preferably analyzed in acidic solutions. This study assesses the reliability of I/Ca measurements in acidic solutions measured with other El/Ca as well as the effects of different sample pre‐treatments on measured foraminiferal I/Ca. Our results show that when samples are measured within hours of prepaparation, the pH of the final solution has an insignificant effect on I/Ca measurements of a carbonate reference material JCp‐1 and a multi‐element standard solution, consistent with the slow kinetics of iodine volatilization. We find, however, that low pH possibly reduces the measured I/Ca in foraminiferal tests in some samples. Our experiments also suggest a resolvable effect of reductive cleaning, yielding lower foraminiferal I/Ca compared to without reductive cleaning. The HNO3 concentration used to dissolve foraminiferal shells has a negligible effect. Despite the different solution pHs and cleaning and dissolving methods, our core top planktic I/Ca data are able to differentiate well‐oxygenated from oxygen‐depleted waters in the upper ocean, and after correcting for cleaning effect, our data are generally consistent with the published studies that analyzed I/Ca without reductive cleaning and in basic solutions. This study shows that measurements of I/Ca within hours of sample dissolutions yield reliable planktic I/Ca data, while also allowing the acquisition of other El/Ca values for paleoceanographic studies

    Research on factors affecting bus fire based on numerical simulation

    No full text
    With the rapid development of economy, the number of buses and bus fire increases. This paper takes bus as the research object and uses software FDS to explore the fire smoke spread under different fire power conditions. The results show that: with the increase in fire power, the smoke in the compartment rapidly accumulates, and the heating rate is also accelerated. The visibility decreases with the diffusion of smoke in the compartment. The CO concentration increases with time. The greater the fire power, the higher the temperature which will eventually stabilize. Only the concentration of smoke near the entrance will be slightly reduced. This is also conducive to the escape of people inside the car

    Engineering metalloporphyrin-integrated nanosystems for targeted sono-/chemo- dynamic therapy of leptomeningeal carcinomatosis through intrathecal administration

    No full text
    Leptomeningeal carcinomatosis (LMC) is a severe complication of cancers that markedly shortens survival and lowers the quality of patients’ life, and it still lacks adequate therapeutic programs. Nanomedicine-mediated therapy has recently presented promising to treat malignant tumors, whereas it remains challenging to deliver nanomedicines for high-efficacy LMC treatment owing to the existence of brain-related delivery barriers. Herein, a novel and effective strategy of combined sonodynamic/chemodynamic therapy (SDT/CDT) of LMC by intrathecal injection of a tumor-targeted metalloporphyrin-integrated nanosystem (MOF@MP-RGD) is developed for the first time. Thereinto, intrathecal administration can directly transport such nanosystems into the cerebrospinal fluid (CSF) around the brain and spinal cord to overcome the brain-related barriers for improving delivery. By building of the orthotopic LMC model, the nanosystems are demonstrated to be effectively accumulated in the LMC area post intrathecal administration due to the arginine-glycine-aspartate (RGD) active targeting, and subsequently excreted out of the body by metabolism process. In vivo evaluations reveal the desirable LMC tumor inhibition and survival prolongation of the combined SDT/CDT based on such biocompatible nanosystems, that is superior to the clinically-used chemotherapeutic drug. Therefore, the combination of intrathecal delivery and nanomedicine-mediated therapy holds great potential for clinical LMC treatment.</p

    Genomic alterations of cerebrospinal fluid cell-free DNA in leptomeningeal metastases of gastric cancer

    No full text
    Abstract Background Leptomeningeal metastases (LM) were rare in gastric cancer (GC), and GC patients with LM (GCLM) generally suffer from poor prognosis. Nevertheless, the clinical utility of cerebrospinal fluid (CSF) circulating tumor DNA (ctDNA) was underinvestigated in GCLM. Methods We retrospectively studied 15 GCLM patients, and all patients had paired primary tumor tissue samples and post-LM CSF samples while 5 patients also had post-LM plasma samples. All samples were analyzed using next-generation sequencing (NGS), and the molecular and clinical features were correlated with clinical outcomes. Results CSF had higher mutation allele frequency (P = 0.015), more somatic mutations (P = 0.032), and more copy-number variations (P < 0.001) than tumor or plasma samples. Multiple genetic alterations and aberrant signal pathways were enriched in post-LM CSF, including CCNE1 amplification and cell cycle-related genes, and CCNE1 amplification was significantly associated with patients’ overall survival (P = 0.0062). More potential LM progression-related markers were detected in CSF samples than in tumor samples, including PREX2 mutation (P = 0.014), IGF1R mutation (P = 0.034), AR mutation (P = 0.038), SMARCB1 deletion (P < 0.001), SMAD4 deletion (P = 0.0034), and TGF-beta pathway aberration (P = 0.0038). Additionally, improvement in intracranial pressure (P < 0.001), improvement in CSF cytology (P = 0.0038), and relatively low levels of CSF ctDNA (P = 0.0098) were significantly associated with better PFS. Lastly, we reported a GCLM case whose CSF ctDNA dynamic changes were well correlated with his clinical assessment. Conclusions CSF ctDNA could more sensitively detect molecular markers and metastasis-related mechanisms than tumor tissues in GCLM patients, and our study sheds light on utilizing CSF ctDNA in prognostic estimation and clinical assessment in GCLM

    Gill Histopathologies Following Exposure to Nanosilver or Silver Nitrate

    No full text
    <div><p>Fish gill is the site for many crucial physiological functions. It is among the first sites of xenobiotic exposure, and gill histopathological alterations may be detected soon after toxicant exposure. Silver (Ag) is one of the most toxic metals to aquatic organisms mainly due to its ability to disrupt ionic regulation. The goal of this study was to determine the effect of ionic and nanoscale Ag on fathead minnow gills by examining gill histology and Na<sup>+</sup>/K<sup>+</sup>-ATPase immunoreactivity. Fathead minnows were exposed to two measured concentrations of silver nitrate (AgNO<sub>3</sub>: 1.3 or 3.7 μg/L as Ag<sup>+</sup>), citrate silver nanoparticles (citrate-AgNP: 15 or 39 μg/L), and polyvinylpyrrolidone-AgNP (PVP-AgNP) (AgNP: 11 or 50 μg/L). Circulatory disturbances were the most prevalent gill alterations detected and were significantly increased in all Ag treatment groups compared to control. AgNO<sub>3</sub> (1.3 μg/L) was the only treatment that significantly elevated the number of total mucous goblet cells present. In all other Ag treatments, the percent of degenerated goblet cells was significantly increased compared to control. When the sum of all histopathological abnormalities (weighted index) was calculated, all Ag groups displayed a significantly higher index, with citrate-AgNP having the highest toxicity (index of 10 ± 0.32 versus 2.4 ± 0.6 in controls). Gill Na<sup>+</sup>/K<sup>+</sup>-ATPase immunoreactivity was decreased by Ag. These results indicated that both AgNO<sub>3</sub> and AgNP created similar disruptions in gill structure and ionic regulation, possibly due to the ionic Ag portion of each treatment. </p></div
    corecore