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1.
Environ Geochem Health ; 43(11): 4847-4861, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34041653

RESUMO

The concentrations, composition patterns, transport and fate of PAHs in semi-arid and arid soils such as in Central Asia are not well known. Such knowledge is required to manage the risk posed by these toxic chemicals to humans and ecosystems in these regions. To fill this knowledge gap, we determined the concentrations of 21 parent PAHs, 4,5-methylenephenanthrene, 6 alkylated PAHs, and biphenyl in soils from 11 sampling locations (0-10, 10-20 cm soil depths) along a 20-km transect downwind from the Almalyk metal mining and metallurgical industrial complex (Almalyk MMC), Uzbekistan. The concentrations of Σ29 PAHs and Σ16 US-EPA PAHs were 41-2670 ng g-1 and 29-1940 ng g-1, respectively. The highest concentration of Σ29 PAHs occurred in the immediate vicinity of the copper smelting factory of the Almalyk MMC. The concentrations in topsoil decreased substantially to a value of ≤ 200 ng g-1 (considered as background concentration) at ≥ 2 km away from the factory. Low molecular weight PAHs dominated the PAH mixtures at less contaminated sites and high molecular weight PAHs at the most contaminated site. The concentration of Σ16 US-EPA PAHs did not exceed the precautionary values set by the soil quality guidelines of, e.g., Switzerland and Germany. Similarly, the benzo[a]pyrene equivalent concentration in soils near the Almalyk MMC did not exceed the value set by the Canadian guidelines for the protection of humans from carcinogenic PAHs in soils. Consequently, the cancer risk due to exposure to PAHs in these soils can be considered as low.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Canadá , China , Ecossistema , Monitoramento Ambiental , Humanos , Metalurgia , Hidrocarbonetos Policíclicos Aromáticos/análise , Medição de Risco , Solo , Poluentes do Solo/análise , Uzbequistão
2.
Environ Sci Technol ; 53(9): 5221-5229, 2019 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-30969111

RESUMO

Antimony(III) mobility in natural aquatic environments is generally enhanced by dissolved organic matter. Tartaric acid is often used to form complexes with and stabilize dissolved Sb(III) in adsorption studies. However, competition between such low-molecular-weight organic acid complexation and adsorption of Sb(III) has received little attention, which prompted us to measure Sb(III) adsorption by iron oxyhydroxide adsorbents commonly used in water treatment plants. Sb K-edge X-ray absorption fine structure (EXAFS) spectra gave Sb-O and Sb-Fe distances and coordinations compatible with a bidentate binuclear inner-sphere complex with trigonal Sb(O,OH)3 polyhedra sharing corners with Fe(O,OH)6 octahedra and a bidentate mononuclear inner-sphere complex but with Sb(O,OH)4 tetrahedra at alkaline pH. Experimental batch titration data were fitted using the charge-distribution multisite surface complexation (CD-MUSIC) model, constrained by the EXAFS molecular level information and taking competitive effects by the organic ligand into consideration. The proportion adsorbed at acid to neutral pH decreased as the Sb(III) concentration increased. The CD-MUSIC adsorption model indicates that this was solely caused by strong competition from tartrate complexation in solution, which leads to adsorption constants higher than those derived without taking this competition into account. The adsorption model results allow for calculating a pe-pH predominance diagram using the USGS PhreePlot code. The study provides consistent surface complexation stability constants, allowing the new database to be used also to reliably model adsorption of toxic oxyanions in anoxic aqueous environments: for example, to accurately simulate competition between Sb(III) and As(III).


Assuntos
Antimônio , Compostos Férricos , Adsorção , Concentração de Íons de Hidrogênio
3.
Death Stud ; 41(9): 585-591, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28436743

RESUMO

According to terror management theory, individuals defend their cultural beliefs following mortality salience. The current research examined whether naturally occurring instances of death (i.e., Ebola) correspond to results found in laboratory studies. The results of two experiments demonstrated that participants experienced a greater accessibility of death-related thoughts in response to an Ebola prime during a regional outbreak. Study 2 also showed that increased mortality awareness following an Ebola manipulation was associated with greater worldview defense (i.e., religious fundamentalism). Together, these results suggest that reminders of death in the form of a disease threat operate similarly to a mortality salience manipulation.


Assuntos
Atitude Frente a Morte , Morte , Doença pelo Vírus Ebola/psicologia , Adolescente , Mecanismos de Defesa , Feminino , Humanos , Masculino , Religião , Autoimagem , Terrorismo , Adulto Jovem
4.
Environ Sci Technol ; 55(5): 3442-3443, 2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33570393
5.
Proc Natl Acad Sci U S A ; 110(10): 3755-9, 2013 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-23431151

RESUMO

Newly developed high-speed, synchrotron-based X-ray computed microtomography enabled us to directly image pore-scale displacement events in porous rock in real time. Common approaches to modeling macroscopic fluid behavior are phenomenological, have many shortcomings, and lack consistent links to elementary pore-scale displacement processes, such as Haines jumps and snap-off. Unlike the common singular pore jump paradigm based on observations of restricted artificial capillaries, we found that Haines jumps typically cascade through 10-20 geometrically defined pores per event, accounting for 64% of the energy dissipation. Real-time imaging provided a more detailed fundamental understanding of the elementary processes in porous media, such as hysteresis, snap-off, and nonwetting phase entrapment, and it opens the way for a rigorous process for upscaling based on thermodynamic models.

6.
Geochem Trans ; 16: 13, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26339199

RESUMO

BACKGROUND: In geochemically perturbed systems where porewater and mineral assemblages are unequilibrated the processes of mineral precipitation and dissolution may change important transport properties such as porosity and pore diffusion coefficients. These reactions might alter the sealing capabilities of the rock by complete pore-scale precipitation (cementation) of the system or by opening new migration pathways through mineral dissolution. In actual 1D continuum reactive transport codes the coupling of transport and porosity is generally accomplished through the empirical Archie's law. There is very little reported data on systems with changing porosity under well controlled conditions to constrain model input parameters. In this study celestite (SrSO4) was precipitated in the pore space of a compacted sand column under diffusion controlled conditions and the effect on the fluid migration properties was investigated by means of three complementary experimental approaches: (1) tritiated water (HTO) tracer through diffusion, (2) computed micro-tomography (µ-CT) imaging and (3) post-mortem analysis of the precipitate (selective dissolution, SEM/EDX). RESULTS: The through-diffusion experiments reached steady state after 15 days, at which point celestite precipitation ceased and the non-reactive HTO flux became constant. The pore space in the precipitation zone remained fully connected using a 6 µm µ-CT spatial resolution with 25 % porosity reduction in the approx. 0.35 mm thick dense precipitation zone. The porosity and transport parameters prior to pore-scale precipitation were in good agreement with a porosity of 0.42 ± 0.09 (HTO) and 0.40 ± 0.03 (µ-CT), as was the mass of SrSO4 precipitate estimated by µ-CT at 25 ± 5 mg and selective dissolution 21.7 ± 0.4 mg, respectively. However, using this data as input parameters the 1D single continuum reactive transport model was not able to accurately reproduce both the celestite precipitation front and the remaining connected porosity. The model assumed there was a direct linkage of porosity to the effective diffusivity using only one cementation value over the whole porosity range of the system investigated. CONCLUSIONS: The 1D single continuous model either underestimated the remaining connected porosity in the precipitation zone, or overestimated the amount of precipitate. These findings support the need to implement a modified, extended Archie's law to the reactive transport model and show that pore-scale precipitation transforms a system (following Archie's simple power law with only micropores present) towards a system similar to clays with micro- and nanoporosity. Graphical abstract.

7.
Environ Sci Technol ; 48(20): 11803-10, 2014 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-25251872

RESUMO

Interaction between the goethite surface and 4-chloro-2-methylphenoxyacetic acid (MCPA) herbicide was studied using density functional theory (DFT) calculations combined with molecular dynamics (MD). The important step made here lies in the use of a periodic DFT method enabling the study of a mineral surface of different protonation states, in strong contrast with previous molecular modeling studies limited to single protonation state corresponding to the point of zero charge. Different surface OH groups and MCPA proton states were used to mimic the strong effects of pH on the outer- and inner-sphere surface complexes that are theoretically possible, together with their binding energies, and their bond lengths. Modeling both a solvated and a protonated (110) goethite surface provided a major breakthrough in the acidic adsorption regime. An outer-sphere complex and a monodentate inner-sphere complex with the neutral MCPA molecule were found to be the most energetically stable adsorbate forms. MD modeling predicted that the latter forms via the sharing of the carbonyl oxygen between the MCPA carboxylate group and a singly coordinated surface hydroxyl group, releasing an H2O molecule. All the other complexes, including the bidentate inner-sphere complex, had higher relative energies and were therefore less likely. The two most likely DFT-optimized structures were used to constrain a surface complexation model applying the charge distribution multisite complexation (CD-MUSIC) approach. The adsorption constants for the complexes were successfully fitted to experimental batch equilibrium data.


Assuntos
Ácido Acético/isolamento & purificação , Herbicidas/isolamento & purificação , Compostos de Ferro/química , Minerais/química , Adsorção , Fracionamento Químico , Meio Ambiente , Concentração de Íons de Hidrogênio , Modelos Teóricos , Simulação de Dinâmica Molecular , Propriedades de Superfície
8.
Environ Sci Technol ; 48(16): 9030-6, 2014 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-25055714

RESUMO

Thallium stable isotope data are used in this study, for the first time, to apportion Tl contamination in soils. In the late 1970s, a cement plant near Lengerich, Germany, emitted cement kiln dust (CKD) with high Tl contents, due to cocombustion of Tl-enriched pyrite roasting waste. Locally contaminated soil profiles were obtained down to 1 m depth and the samples are in accord with a binary mixing relationship in a diagram of Tl isotope compositions (expressed as ε(205)Tl, the deviation of the (205)Tl/(203)Tl ratio of a sample from the NIST SRM 997 Tl isotope standard in parts per 10(4)) versus 1/[Tl]. The inferred mixing endmembers are the geogenic background, as defined by isotopically light soils at depth (ε(205)Tl ≈ -4), and the Tl emissions, which produce Tl-enriched topsoils with ε(205)Tl as high as ±0. The latter interpretation is supported by analyses of the CKD, which is also characterized by ε(205)Tl ≈ ± 0, and the same ε(205)Tl value was found for a pyrite from the deposit that produced the cocombusted pyrite roasting waste. Additional measurements for samples from a locality in China, with outcrops of Tl sulfide mineralization and associated high natural Tl backgrounds, reveal significant isotope fractionation between soils (ε(205)Tl ≈ +0.4) and locally grown green cabbage (ε(205)Tl between -2.5 and -5.4). This demonstrates that biological isotope fractionation cannot explain the isotopically heavy Tl in the Lengerich topsoils and the latter are therefore clearly due to anthropogenic Tl emissions from cement processing. Our results thus establish that isotopic data can reinforce receptor modeling for the toxic trace metal Tl.


Assuntos
Isótopos/análise , Poluentes do Solo/análise , Tálio/análise , Brassica/química , China , Materiais de Construção , Monitoramento Ambiental , Alemanha , Resíduos Industriais , Ferro , Sulfetos
9.
Ecotoxicology ; 23(5): 880-97, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24676936

RESUMO

The main goal of the present study was to determine the effect of the native vegetation on the successive development of the soil ecosystem at abandoned coal-ash landfills of the Angren coal-fired power plant in Uzbekistan. Two different landfills (one not in use for 3 years, termed newer, and the other not in use for 10 years, termed older) with different degrees of vegetation cover were chosen to assess the time and vegetation effects on soil biota and habitat development. The soil biotic structure, including soil microorganisms and soil free-living nematode communities, was investigated both at open plots and under different native plants at the coal-ash landfill area. The observed soil microorganisms were found to be the most important component of the observed ecosystems. Total abundance, biomass, species, trophic and sexual diversity of soil free-living nematodes, along with fungi and organic-matter content, were found to be correlated with trace metals. The nematode trophic and species abundance and diversity increased from the newer toward the older coal-ash landfills. The sex ratio of the nematode communities was found to be dependent on the environmental conditions of the study area, with the males being the most sensitive nematode group. All applied ecological indices confirmed that open landfill plots distant from plants are the most unfavorable areas for soil biota. In that respect, the native plants Alhagi maurorum Desv. and Tamarix sp. were found to be important environmental components for the natural remediation of a soil ecosystem in the coal-ash landfill area.


Assuntos
Cinza de Carvão/toxicidade , Ecossistema , Nematoides , Microbiologia do Solo , Solo/química , Animais , Feminino , Masculino , Uzbequistão
10.
Environ Sci Technol ; 47(1): 198-204, 2013 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-22924476

RESUMO

We combined a noninvasive tomographic imaging technique with an invasive open-system core-flooding experiment and compared the results of the pre- and postflooded states of an experimental sandstone core sample from an ongoing field trial for carbon dioxide geosequestration. For the experiment, a rock core sample of 80 mL volume was taken from the 629 m Stuttgart Formation storage domain of a saline sandstone aquifer at the CCS research pilot plant Ketzin, Germany. Supercritical carbon dioxide and synthetical brine were injected under in situ reservoir p/T-conditions at an average flow rate of 0.1 mL/min for 256 h. X-ray computed microtomographic imaging was carried out before and after the core-flooding experiment at a spatial voxel resolution of 27 µm. No significant changes in microstructure were found at the tomographic imaging resolution including porosity and pore size distribution, except of an increase of depositional heterogeneous distribution of clay minerals in the pores. The digitized rock data were used as direct real microstructure input to the GeoDict software package, to simulate Navier-Stokes flow by a lattice Boltzmann equation solver. This procedure yielded 3D pressure and flow velocity fields, and revealed that the migration of clay particles decreased the permeability tensor probably due to clogging of pore openings.


Assuntos
Silicatos de Alumínio/química , Dióxido de Carbono/química , Sequestro de Carbono , Argila , Fenômenos Geológicos , Água Subterrânea/química , Permeabilidade , Porosidade , Salinidade , Sais/química , Microtomografia por Raio-X
11.
Environ Pollut ; 334: 122202, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37453683

RESUMO

Porewater arsenic mobility above the groundwater table has been recognized as a potential cause of arsenic-rich groundwater, but the processing pathways of dissolved organic matter (DOM) in that hyporheic zone and their effect on porewater arsenic release remain poorly understood. To address these issues, two porewater profiles were sampled in a surface water-groundwater interaction zone from the Hetao Basin, China, to monitor the porewater geochemistry and DOM molecular characteristics. The results show that the porewater arsenic, Fe(II), and DOC concentrations were all significantly higher than those of the intruding pond water, and were located above the conservative mixing model lines. This indicates a net release of these solutes from the sediment. By comparing the porewater with pond water DOM, we found that the carboxyl-rich alicyclic molecules (CRAM) were selectively preserved, carbohydrates and aliphatics/proteins were preferentially consumed, and low O/C-ratio compounds with high bioproduction index (I_bioprod) and terrestrial index (I_terr) were produced. The transformation of CHO to CHOS compounds also represented a pathway of recalcitrant DOM production. The produced recalcitrant organic compounds mostly contributed to the elevated porewater DOC concentrations, but their contribution decreased along the filtration path. The consumption of labile DOM compounds would be responsible for Fe(III) hydroxide reduction and arsenic release. The generated recalcitrant DOM may also be a driver of porewater arsenic mobility by acting as electron shuttles. This study highlights the importance of the hyporheic zone in shaping shallow groundwater DOM composition and the potential contribution to arsenic enrichment.


Assuntos
Arsênio , Água Subterrânea , Poluentes Químicos da Água , Água , Matéria Orgânica Dissolvida , Arsênio/análise , Compostos Férricos , Água Subterrânea/química , China , Poluentes Químicos da Água/análise
12.
J Hazard Mater ; 445: 130482, 2023 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-36473256

RESUMO

Quantitative characteristics and sizes of nanoparticles (NPs) in coal fly ash (CFA) produced in coal-fired power plants as a function of coal type and plant design will help reveal the NP emission likelihood and their environmental implications. However, little is known about how combustion conditions and types of coal regulate the NP abundance in CFAs. In this study, based on single particle (SP)-ICP-MS technology, particle number concentrations (PNCs) and sizes of Fe- and Ti-containing NPs in CFAs were determined for samples collected from power plants of different designs and burning different types of coal. The PNCs of Fe- and Ti-containing NPs in all CFAs measured were in the range of 1.3 × 107 - 3.4 × 108 and 6.8 × 106 - 2.2 × 108 particles/mg, with the average particle sizes of 111 nm and 87 nm, respectively. The highest Fe-NP PNCs likely relate to the highest contents of Fe and pyrite in the feed coal. In addition, high TOC in CFAs are associated with metal-containing NPs, resulting in elevated abundances of these NPs with relatively large sizes. Moreover, elevated PNCs of NPs were found in CFAs produced by coal-fired power plants burning low-rank coals and with small installed capacity (especially those under 100-MW units). Compared to cyclone filters, ESPs and FFs with higher removal efficiency typically retain more Fe-/Ti- containing NPs with smaller sizes. Based on a structural equation (SE) model, raw coal properties (coal rank and Fe/Ti content), boiler types, and efficiency of particulate emission control devices likely indirectly affect PNCs of Fe- and Ti-containing NPs by influencing TOC contents and their corresponding metal concentrations of CFAs. This study provides the first analytic and comprehensive information concerning the direct and indirect regulating factors on NPs in various CFAs.

13.
Environ Sci Technol ; 45(22): 9799-805, 2011 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-21970732

RESUMO

With the increase in the awareness of the public in the environmental impact of oil shale utilization, it is of interest to reveal the mobility of potentially toxic trace elements in spent oil shale. Therefore, the Cr and As oxidation state in a representative Jordanian oil shale sample from the El-Lajjoun area were investigated upon different lab-scale furnace treatments. The anaerobic pyrolysis was performed in a retort flushed by nitrogen gas at temperatures in between 600 and 800 °C (pyrolytic oil shale, POS). The aerobic combustion was simply performed in porcelain cups heated in a muffle furnace for 4 h at temperatures in between 700 and 1000 °C (burned oil shale, BOS). The high loss-on-ignition in the BOS samples of up to 370 g kg(-1) results from both calcium carbonate and organic carbon degradation. The LOI leads to enrichment in the Cr concentrations from 480 mg kg(-1) in the original oil shale up to 675 mg kg(-1) in the ≥ 850 °C BOS samples. Arsenic concentrations were not much elevated beyond that in the average shale standard (13 mg kg(-1)). Synchrotron-based X-ray absorption near-edge structure (XANES) analysis revealed that within the original oil shale the oxidation states of Cr and As were lower than after its aerobic combustion. Cr(VI) increased from 0% in the untreated or pyrolyzed oil shale up to 60% in the BOS ash combusted at 850 °C, while As(V) increased from 64% in the original oil shale up to 100% in the BOS ash at 700 °C. No Cr was released from original oil shale and POS products by the European compliance leaching test CEN/TC 292 EN 12457-1 (1:2 solid/water ratio, 24 h shaking), whereas leachates from BOS samples showed Cr release in the order of one mmol L(-1). The leachable Cr content is dominated by chromate as revealed by catalytic adsorptive stripping voltammetry (CAdSV) which could cause harmful contamination of surface and groundwater in the semiarid environment of Jordan.


Assuntos
Arsênio/química , Cromo/química , Petróleo/análise , Temperatura Alta , Jordânia , Oxirredução
14.
Mol Cell Proteomics ; 8(12): 2827-42, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19752005

RESUMO

Proteome-based technologies represent powerful tools for the analysis of protein expression profiles, including the identification of potential cancer candidate biomarkers. Thus, here we provide a comprehensive protein expression map for clear cell renal cell carcinoma established by systematic comparative two-dimensional gel electrophoresis-based protein expression profiling of 16 paired tissue systems comprising clear cell renal cell carcinoma lesions and corresponding tumor-adjacent renal epithelium using overlapping narrow pH gradients. This approach led to the mapping of 348 distinct spots corresponding to 248 different protein identities. By implementing restriction criteria concerning their detection frequency and overall regulation mode, 28 up- and 56 down-regulated single target spots were considered as potential candidate biomarkers. Based on their gene ontology information, these differentially expressed proteins were classified into distinct functional groups and according to their cellular distribution. Moreover, three representative members of this group, namely calbindin, gelsolin, and heart fatty acid-binding protein, were selected, and their expression pattern was analyzed by immunohistochemistry using tissue microarrays. Thus, this pilot study provides a significant update of the current renal cell carcinoma map and defines a number of differentially expressed proteins, but both their potential as candidate biomarkers and clinical relevance has to be further explored in tissues and for body fluids like serum and urine.


Assuntos
Carcinoma de Células Renais/metabolismo , Eletroforese em Gel Bidimensional/métodos , Neoplasias Renais/metabolismo , Proteínas de Neoplasias/metabolismo , Proteômica/métodos , Calbindinas , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/patologia , Epitélio/metabolismo , Epitélio/patologia , Proteína 3 Ligante de Ácido Graxo , Proteínas de Ligação a Ácido Graxo/metabolismo , Gelsolina/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Neoplasias Renais/genética , Neoplasias Renais/patologia , Proteínas de Neoplasias/genética , Projetos Piloto , Reprodutibilidade dos Testes , Proteína G de Ligação ao Cálcio S100/metabolismo , Análise Serial de Tecidos
15.
J Environ Monit ; 13(7): 2033-41, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21655572

RESUMO

The state of contamination of tropical environments, particularly in Africa, remains a relatively under explored subject. Here, we determined polycyclic aromatic hydrocarbon (PAH) and trace metal concentrations in coastal sediment and biota samples (fish and mussels) from Togo (West Africa). In the sediments, the ∑21 PAH concentrations ranged from <4 ng g(-1) to 257 ng g(-1), averaging 92 ng g(-1). Concentration ratios of low molecular weight PAHs (2-3 rings) versus high molecular weight PAHs (≥4 rings) were always lower than 1 (ranging from 0.08 to 0.46) indicating that high molecular weight PAHs were dominant in all sediment samples, and that PAHs originated mainly from anthropogenic combustion activities. The sediments were also analyzed for major elements and a total of 15 trace metals, which were found in elevated concentrations. The calculated enrichment factor (EF) values relative to the Earth's crust show that the contamination is extremely severe for Cd (EF = 191), severe for Cr (EF = 18) and U (EF = 17.8), moderately severe for Zr (EF = 8.8), for Ni (EF = 6.8), Sr (EF = 5.9) and Ba (EF = 5.4), and moderate for V (EF = 3.6) and Zn (EF = 3.4). Sediments sampled in areas affected by the dumping of phosphorite mine tailings showed particularly high concentrations of trace metals. Overall, concentrations of both PAHs and trace metals in sediment tend to increase from the coastline to the open sea (2 km offshore). This is attributable to the increasingly finer texture of coastal sediment found offshore, which has a terrigenous origin and appears loaded with various contaminants through adsorption processes. Such high loads of trace metals were also found in the biota (fish and mussels). The ratio of measured trace metal concentrations in biota to threshold limits set by the World Health Organization herein defined as relative health factor (RHF) was high. Average RHF values in fish were highest for Se (470), As (250), Ag (97), Ni (78), Mn (63), Fe (53), Pb (36), Cd (10), and Cr (7) while lowest for Cu (0.08) and Zn (0.03). Cd and Al did not bioaccumulate in the analyzed fish species. In mussels, the RHF values were highest for Fe (9,108), As (295), Pb (276), Se (273), Mn (186), Ni (71), Ag (70), Cd (14), and Cu (4).


Assuntos
Sedimentos Geológicos/química , Metais/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , Animais , Organismos Aquáticos/metabolismo , Biota , Bivalves/metabolismo , Monitoramento Ambiental , Peixes/metabolismo , Metais/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Água do Mar/química , Togo , Poluentes Químicos da Água/metabolismo
16.
J Hazard Mater ; 414: 125512, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-33647621

RESUMO

Competitive adsorption of arsenate (AsO43-) and phosphate (PO43-) on α-FeOOH, LaOOH, and nano-TiO2 was studied using batch adsorption experiments and in-situ flow cell ATR-FTIR coupled with two-dimensional correlation spectroscopy (2D-COS) for the first time. With a higher temporal resolution, our results found a highly dynamic adsorption sequence for AsO43- and PO43-. When AsO43- and PO43- were simultaneously exposed to the adsorbents at the same concentrations, AsO43- was preferentially adsorbed by α-FeOOH and TiO2, but PO43- adsorption was dominant on LaOOH. The results implied that the PO43- adsorbed on LaOOH had to be remobilized to allow for AsO43- adsorption, but that PO43- adsorption on α-FeOOH and TiO2 was hindered by faster AsO43- adsorption. Crystal orbital Hamilton population (COHP) analysis revealed that AsO43- complexes bonded more strongly on α-FeOOH and TiO2, whereas PO43- complexes were more stable on LaOOH. Different adsorption sequences and the stability of the complexes were attributed to the diverse geometric configurations of AsO43- and PO43- on metal oxides surfaces with specific bonding chemistry. The presence of Ca2+ did not affect AsO43- and PO43- adsorption sequence on α-FeOOH or LaOOH, but it reversed the adsorption sequence on TiO2 due to the formation of ternary surface complexes on TiO2 surfaces.

17.
Hemoglobin ; 34(6): 561-4, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21077763

RESUMO

Routine hemoglobin (Hb) analyses identified a new ß-globin variant in a family from East Timor. The red cell indices were within normal limits for all affected family members. The variant is due to a missense mutation at amino acid codon 80 (AAC>CAC) which results in the substitution of histidine for asparagine.


Assuntos
Hemoglobinas Anormais/genética , Mutação de Sentido Incorreto , Globinas beta/genética , Adolescente , Adulto , Sequência de Bases , Criança , Cromatografia Líquida de Alta Pressão , Análise Mutacional de DNA , Saúde da Família , Feminino , Humanos , Concentração de Íons de Hidrogênio , Masculino , Timor-Leste
18.
Water Res X ; 9: 100061, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32817931

RESUMO

Granular ferric hydroxide (GFH) is often used for fixed bed adsorbent (FBA) columns in groundwater purification units around the world to remove arsenate contaminations. Groundwater can contain also other toxic (e.g., antimonite and vanadate) and non-toxic oxo-anions (phosphate and silicic acid) that are known to affect FBA lifetimes. Therefore, understanding the breakthrough of toxic compounds intended for removal by FBA is essential to their design, and is important to predict accurately breakthrough curves (BTCs) for FBAs in waterworks to plan future operating costs. Rapid small-scale column tests (RSCCT) and pilot-scale FBA were used to simulate vanadate BTCs for complex groundwater chemistries. The BTCs were simulated successfully using a homogeneous surface diffusion model (HSDM) combining equilibrium chemical adsorption and kinetic mass transfer. Adsorption parameters for various groundwater compositions were predicted using the CD-MUSIC surface complexation model, which was set up for the first time for akaganéite-based granular ferric hydroxide with a competitive multi-solute system. The results indicated that V(V) is less prone to competitive adsorption effects, and use of the homogeneous surface diffusion model to predict the BTCs requires then the kinetic mass transfer Biot number to be used as the only fitting parameter. On the other hand, a concentration overshoot could be observed for the two weaker absorbed oxo-anions arsenate and phosphate because of displacement by the vanadate. Results of pilot scale test column BTCs of vanadate for three waterworks with different groundwater compositions could be favorably extrapolated with a unique Freundlich constant kF of 3.2 derived on basis of the multi-solute CD-MUSIC model, and a unique Biot number of 37 fixed for all three different test sites.

19.
Palliat Med Rep ; 1(1): 259-263, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33274341

RESUMO

Background: Before the Affordable Care Act (ACA), the financing landscape for fee-for-service health care lacked broad structure and incentives to provide palliative care outside hospitals. Since the ACA, several payers have taken the opportunity to offer home-based palliative care (HBPC) to their members. Objective: To evaluate the impact of outreach efforts by a physician champion among a cohort of primary care physicians (PCPs) to introduce a new HBPC program and benefit, obtain buy-in, and motivate referrals for Blue Shield patients. Design: Secondary qualitative analysis of detailed field notes from a HBPC physician champion from in-person meetings with a cohort of PCPs and their office staff. Subjects: PCPs were from a physicians group in northern California that met with the physician champion during a 12-month study period. Results: During the 12-month study period, the physician champion met with clinicians at 27 distinct primary care offices. Qualitative analyses revealed three independent themes relating to receptivity and perception of the new HBPC program: (1) physician-level factors (overburdened, lack of palliative care knowledge, misconceptions around palliative care, and patient control), (2) practice-level factors (practice structure and role/integration of advance practice providers), and (3) first impression of the HBPC program (receptivity, "dirty data," and communication). Conclusion: Results hold important implications for practice and new approaches to engaging PCPs in HBPC, obtaining buy-in, and generating patient referrals. PCPs need better support in caring for patients with serious illness and HBPC can likely fill that role if PCPs are willing to refer and HBPC programs adapt.

20.
Proteomics ; 9(11): 3011-21, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19526545

RESUMO

Low oxygen tension was proposed to be one of the environmental parameters characteristic of the patho-physiological conditions of natural infections by Brucella suis. We previously showed that various respiratory pathways may be used by B. suis in response to microaerobiosis and anaerobiosis. Here, we compare the whole proteome of B. suis exposed to such low-oxygenated conditions to that obtained from bacteria grown under ambient air using 2-D DIGE. Data showed that the reduction of basal metabolism was in line with low or absence of growth of B. suis. Under both microaerobiosis and anaerobiosis, glycolysis and denitrification were favored. In addition, fatty acid oxidation and possibly citrate fermentation could also contribute to energy production sufficient for survival under anaerobiosis. When oxygen availability changed and became limiting, basic metabolic processes were still functional and variability of respiratory pathways was observed to a degree unexpected for a strictly aerobic microorganism. This highly flexible respiration probably constitutes an advantage for the survival of Brucella under the restricted oxygenation conditions encountered within host tissue.


Assuntos
Proteínas de Bactérias/metabolismo , Brucella suis/metabolismo , Oxigênio/metabolismo , Proteômica/métodos , Anaerobiose , Proteínas de Bactérias/análise , Brucella suis/química , Brucella suis/genética , Eletroforese em Gel Bidimensional , Glicólise , Redes e Vias Metabólicas , Nitrato Redutase/biossíntese , Nitrato Redutase/genética , Nitrato Redutase/metabolismo , Regiões Promotoras Genéticas , Proteoma/metabolismo , Estresse Fisiológico
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