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Use of Flame Atomic Absorption Spectroscopy and Multivariate Analysis for the Determination of Trace Elements in Human Scalp

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American Journal of Analytical Chemistry 2013年第7期4卷 348-359页

作者： Sayo O. Fakayode Sri Lanka Owen david A. Pollard Mamudu Yakubu Department of Chemistry Winston-Salem State University Winston-Salem USA

The analysis of trace elements in human hair for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostics, and forensic science. This study investigated the concentrations of essential and toxic elements (Fe, Mg, Ca, Cu, Zn, cr, Cd, and Pb) using flame atomic absorption spectroscopy (FAAS) in human scalp hair obtained from subjects living in Forsyth County, North Carolina, USA. The influence of age, sex, race, and smoking habits on the levels of trace elements in the hair samples were also investigated. Additionally, analyses were subjected to a statistical, regression, and principal component analysis to evaluate inter-elemental association and possible pattern recognition in hair samples. Furthermore, Ca/Mg and Zn/Cu ratios, which are often used to evaluate the degree of Ca and Cu utilization in humans and as markers for various health related issues including, atherosclerosis, hypertension, insulin sensitivity, and pancreatic cancer, were calculated. The overall mean concentrations of Fe (25 μg/g), Ca (710 μg/g), Mg (120 μg/g), Zn (190 μg/g), Cu (12 μg/g), and cr (0.20 μg/g) were found in hair samples. The trace element concentrations varied widely in hair samples as demonstrated by large range of concentrations obtained for each element. However, levels of Cd and Pb elements of cr in hair samples and the calculated Ca/Mg and Zn/Cu ratios were found to be largely correlated with age, race, sex, and smoking habits.

关键词： Human Scalp Hair Biomonitoring Trace Element Concentration Flame Atomic Absorption Spectroscopy Regression and Principal Component Analysis Inter-Element Association

Trace elements migrating from tailings to rock varnish laminated sediments in an old mining region from Nelson,Nevada,USA

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International Journal of Sediment Research 2022年第2期37卷 202-213页

作者： Douglas B.Sims Amanda C.Hudson John E.Keller Michael Strange Andressa cristhy Buch david Ferrari Giavanna M.Fernandez Juan Garcia-Hernandez Bailey D.Kesl Sean Torres Department of Physical Sciences College of Southern Nevada University of Nevada Fluminense Federal University

The dispersion and influence of soluble and particulate trace elements(TEs) present in the materials from abandoned mines is an imminent problem on terrestrial and aquatic *** goal of this research is to provide a broader view of such transport,assessing particle size distribution and TE interactions(e.g.,scavenging) with mine tailings and locally derived sediments transported by water in arid *** grains from wash sediment were collected from a dry ephemeral wash in Nelson,Nevada where the Techatticup Mine and Mill worked between 1850 and *** were evaluated to determine the association and behavior of certain metals and metalloids including aluminum,arsenic,barium,cadmium,copper,chromium,iron,manganese,lead,selenium,vanadium,and zinc to rock varnish laminated *** show that some metals and metalloids were more concentrated on larger particles whereas others indicated the opposite *** example,As was greatest on silt fractions and least on coarse fractions,while Se was detected only on ***,Cu,Fe,Mn,Pb,and Zn concentrations all increased with decreasing particle size(silt> sand> coarse),whereas Al,Ba,and V showed the opposite trend(silt cr,V,and Mn suggested a possible greater affinity of these metals to the Al,Fe,and Mn oxides from the RV *** data found in this study show that transport of contaminated sediments in arid regions could lead to the enrichment of some TEs in downgradient areas from source materials.

关键词： Adsorption Metals Metalloids Mine tailings Particle size Transport

Biosorption of heavy metals from aqueous solution by Gracilaria corticata varcartecala and Grateloupia lithophila

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Journal of Coastal Life Medicine 2013年第2期 102-107页

作者： Narayanaswamy Tamilselvan Jothi Hemachandran Thirunavukarasu Thirumalai Chacko Vijai Sharma Krishnan Kannabiran Ernest david P.G and Research Department of Zoology Physiology WingVoorhees College-632001.TamilnaduIndia Department of Biomolecules and Genetic Division VIT UniversityVellore-632014TamilnaduIndia Department of Biotechnology Thiruvalluvar UniversitySerkaduVellore-632115TamilnaduIndia

Objective:To study the biosorption of heavy metals viz.,cr(VI),cr(III),Hg(II),Pb(II)and Cd(II)using Gracilaria corticata varcartecala(*** varcartecala)and Grateloupia lithophila(***)***:Batch biosorption and acid digestion methods were *** physical and chemical parameters were optimized for ***:Both seaweeds absorb Hg(II)upto 99.9%and 98.2%in batch biosorption method;whereas in acid digestion method,cr(III)absorbed upto 96.49%by *** varcartecala and Pb(II)absorbed upto 93.71%by ***-IR analysis was used to know the involvement of different functional groups in the biosorption *** electron microscopy was carried out to study the morphological cell surface changes due to ***:It can be concluded that *** varcartecala and *** are potential algal species for effective removal of heavy metals namely cr(VI),cr(III),Hg(II),Pb(II)and Cd(II)from environmental sources.

关键词： Biosorption,Heavy metals Gracilaria corticata varcartecala,Grateloupia lithophila,SEM

Development of a Real-Time Ion Spectrometer with a Scintillator for Laser-Driven Ion Acceleration Experiments

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Chinese Physics Letters 2011年第9期28卷 194-197页

作者： XU Miao-Hua LI Hong-Wei LIU Bi-Cheng LIU Feng SU Lu-Ning DU Fei ZHANG Lu ZHENG Yi MA Jing-Long david Neely Paul McKenna WANG Zhao-Hua WEI Zhi-Yi YAN Xue-Qing LI Yu-Tong LI Ying-Jun ZHANG Jie Department of Physics China University of Mining&Technology(Beijing)Beijing 100083 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190 State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871 Central Laser Facility STFCRutherford Appleton LaboratoryDidcot OX110QXUK SUPA Department of PhysicsUniversity of StrathclydeGlasgow G40NGUK Department of Physics Shanghai Jiao Tong UniversityShanghai 200240

A real-time ion spectrometer mainly based on a high-resolution Thomson parabola and a plastic scintillator is designed and *** spectrometer is calibrated by protons from an electrostatic *** feasibility and reliability of the diagnostics are demonstrated in laser-driven ion acceleration experiments performed on the XL-II laser *** proton spectrum extrapolated from the scintillator data is in excellent agreement with the cr39 spectrum in terms of beam temperature and the cutoff *** real-time spectrometer allows an online measurement of the ion spectra in single shot,which enables efficient and statistical studies and applications in high-repetition-rate laser acceleration experiments.

关键词： acceleration spectrum electrostatic

Ecosystem management in transition in Central and Eastern Europe: the need for a vision

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Ecosystem Health and Sustainability 2016年第8期2卷 1-3页

作者： david Vačkář András Báldi Global Change Research Institute(CzechGlobe) The Czech Academy of SciencesBělidla 986/4a60300 BrnoCzech Republic MTA Centre for Ecological Research Institute of Ecology and BotanyHungarian Academy of SciencesH-2163 Alkotmány u.2-4VácrátótHungary Corresponding address:Department of Human Dimensions of Global Change Global Change Research Institute CASV Jirchářích 149/611000 Prague 1Czech Republic

It is well established that in current human-dominated world,environmental change is closely coupled with socio-economic factors,and this is reflected in conceptual frameworks of important policies(Díaz et al.2015).Humans are adversely affecting biodiversity and climate change on a planetary scale(Rockström et al.2009).Anthropogenic transformation of ecosystems has been driven by rapid social and economic changes,manifested by direct drivers such as land use change and climate change(Nelson et al.2006).Central and Eastern Europe(CEE)has been a rap-idly transitioning region in terms of economic growth and political *** the collapse of former Eastern Bloc and revolutions in several CEE countries after 1989,CEE countries have been undergoing political and economic transformation toward democracy and free *** accession to the European Union also brought in changes of political environment and ecosystem management possibilities and *** socioeconomic changes have influenced environmental condition and ecosystem management in this region,with changing pres-sures on biodiversity and ecosystem *** changes in Central and Eastern Europe have been closely linked especially to agricultural *** example,inorganic fertilizer use in several CEE countries dropped in a single year to 25%of its former level after the collapse of ***,in turn,had an enormous impact on farmland biodiversity(Stoate et al.2009).

关键词： Eastern Central farmland

Advances in Tropical Soil Characterization via Portable X-Ray Fluorescence Spectrometry

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Pedosphere 2019年第4期29卷 468-482页

作者： Elen A. SILVA david C. WEINDORF Sergio H. G. SILVA Bruno T. RIBEIRO Giovana C. POGGERE Teotonio S. CARVALHO Mariana G. M. GONQALVES Luiz R. G. GUILHERME Nilton CURI Department of Soil Science Federal University of Lavras Lavras 37200-000 (Brazil) Department of Plant and Soil Science Texas Tech University Texas 79409-2122 (USA)

Portable X-ray fluorescence(pXRF) spectrometers can be used to determine the elemental composition easily, rapidly, and without using chemical reagents, which is very important for tropical regions due to the lack of detailed soil characterization data. Moreover,pXRF data can be used to predict the results of more expensive, time-consuming, and conventional laboratory analyses. This study sought to determine the elemental composition of various soil profiles using pXRF. Two operational modes(Trace Mode and General Mode) and two scanning time(30 and 60 s) were assessed to determine their effects on the correlation of pXRF dataset with respect to conventional inductively coupled plasma(ICP)-optical emission spectrometry analysis. This relationship has been reported in previous studies, however, few studies were performed on tropical soils, which are unique. Furthermore, such relationships establish the viability of developing prediction models directly from pXRF data. Linear regression was applied to develop calibration models for the prediction of ICP analysis results and exchangeable and available elemental contents based on pXRF data. High coefficients of determination(R^2) were obtained for Ca(0.87), Cu(0.90), Fe(0.95), Mn(0.85), cr(0.95), V(0.72), and Ni(0.90), with adequate validation. Statistically significant results were not found for Al, K, Zn, Ti, and Zr. The models predicting the exchangeable Ca based on the total Ca from p XRF reached an R^2 of up to 0.85. Operational modes influenced the pXRF results. Our results illustrate that pXRF holds great promise for tropical soil characterization and the development of prediction models, justifying the need for larger-scale studies in tropical countries worldwide.

关键词： elemental composition exchangeable Ca inductively coupled plasma operational mode prediction models scanning time soil analysis total elemental content

Advanced mid-infrared plasmonic waveguides for on-chip integrated photonics

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Photonics Research 2023年第10期11卷 1694-1702页

作者： MAURO david davidE DISNAN ELENA ARIGLIANI ANNA LARDSCHNEIDER GEORG MARSCHICK HANH T.HOANG HERMANN DETZ BERNHARD LENDL ULRICH SCHMID GOTTFRIED STRASSER BORISLAV HINKOV Institute of Solid State Electronics and Center for Micro-and Nanostructures TU WienViennaAustria Institute of Sensor and Actuator Systems TU WienViennaAustria Central European Institute of Technology Brno University of TechnologyBrnoCzech Republic Institute of Chemical Technologies and Analytics ViennaAustria

Long-wave infrared(LWIR, 8–14 μm) photonics is a rapidly growing research field within the mid-IR with applications in molecular spectroscopy and optical free-space communication. LWIR applications are often addressed using rather bulky tabletop-sized free-space optical systems, preventing advanced photonic applications,such as rapid-time-scale experiments. Here, device miniaturization into photonic integrated circuits(PICs) with maintained optical capabilities is key to revolutionize mid-IR photonics. Subwavelength mode confinement in plasmonic structures enabled such miniaturization approaches in the visible-to-near-IR spectral range. However,adopting plasmonics for the LWIR needs suitable low-loss and-dispersion materials with compatible integration strategies to existing mid-IR technology. In this paper, we further unlock the field of LWIR/mid-IR PICs by combining photolithographic patterning of organic polymers with dielectric-loaded surface plasmon polariton(DLSPP) waveguides. In particular, polyethylene shows favorable optical properties, including low refractive index and broad transparency between ~2 μm and 200 μm. We investigate the whole value chain, including design, fabrication, and characterization of polyethylene-based DLSPP waveguides and demonstrate their first-time plasmonic operation and mode guiding capabilities along S-bend structures. Low bending losses of ~1.3 d B and straight-section propagation lengths of ~1 mm, pave the way for unprecedented complex on-chip mid-IR photonic devices. Moreover, DLSPPs allow full control of the mode parameters(propagation length and guiding capabilities) for precisely addressing advanced sensing and telecommunication applications with chip-scale devices.

关键词： waveguides transparency straight

Extraction Characteristics of Selenium as Affected by Coal Fly Ash Type, Water Extractant, and Extraction Time

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Journal of Environmental Protection 2014年第12期5卷 1126-1144页

作者： Mark A. Cantrell Kristofor R. Brye david M. Miller Esten Mason Julian Fairey AEP-Swepco Flint Creek Power Plant Gentry AR USA Department of crop Soil and Environmental Sciences University of Arkansas Fayetteville AR USA Department of Civil Engineering University of Arkansas Fayetteville AR USA

Selenium (Se) contamination can be a potential groundwater concern near un-lined coal ash landfills. Of all the Environmental Protection Agency’s priority and non-priority pollutants, Se has the narrowest concentration range considered beneficial and detrimental for aquatic and terrestrial organisms. The effects of ash type (i.e., fresh and weathered), water-extractant type (i.e., deionized water, rainwater, and groundwater), and extraction time (i.e., 2 and 6 hours) on Se, arsenic (As), and chromium (cr) concentrations were investigated from Class C, subbituminous coal fly ash produced at the Flint creek Power Plant (Benton County, AR). Water-extractable Se concentrations differed (p = 0.03) between ash types across water-extractants, but were unaffected (p > 0.05) by extraction times. Unexpectedly, fresh ash water-extractable Se concentrations were below minimum detection limits (i.e., 2.0 μg·L-1) for all treatments. In contrast, averaged over extraction times, the water-extractable Se concentration from weathered ash was greatest (p cr to aid in the development of sustainable fly ash management strategies.

关键词： Arsenic Chromium Coal Fly Ash Landfill Selenium

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应用HBI优化炼钢工艺

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