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1.
Appl Opt ; 59(26): 7752-7759, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32976445

RESUMO

Trace element analysis of soft materials, to determine the content of low concentration elements, is important in many industries such as food quality control and medical biopsy analysis. Many of these applications would benefit from faster analysis with smaller sample requirements. Further, some natural samples are soft and have high water content, which brings challenges to element analysis. Here, we develop a cryogenic pelletization pretreatment to address those challenges. The soft samples are cryogenically milled, freeze-dried, and pelletized before elemental analysis. Analysis is performed by laser ablation spectroscopy, the combination of laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS), to rapidly analyze light and heavy analytes. For this initial study, aluminum (Al) content in soft samples is determined by LIBS and lead (Pb) content by LA-ICP-MS. The standard addition method is performed to build calibration curves for element quantification. The measurements are compared with a Hong Kong government certified acid digestion and ICP-MS procedure. The experiment is performed on standard reference materials and selected food samples. The relative errors compared with certified measurements are less than 10% for all samples, with Al content ranging from 63-1466 µg/g and Pb content from 0.37-2.35 µg/g (dry mass). Microscopy of pellets shows that laser ablation spectroscopy can be performed with 100 µg of sample (dry mass). Total analysis time from raw sample to final measurement, including preparation, is under 1 h. The results indicate that the laser ablation spectroscopy with cryogenic pelletization is a promising technique for many applications such as screening of small food samples for toxic metals and trace element analysis of millimeter biopsies.


Assuntos
Contaminação de Alimentos , Espectrometria de Massas/métodos , Análise Espectral/métodos , Oligoelementos/análise , Compostos de Alumínio/análise , Terapia a Laser , Chumbo/análise , Padrões de Referência , Manejo de Espécimes
2.
Langmuir ; 35(3): 628-640, 2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30607960

RESUMO

Associating MnO2 with carbonaceous supports profoundly enhances capacitive deionization (CDI) efficiency. A fundamental question of how the surface chemistry of MnO2 itself influences CDI efficiency is not yet fully understood. In this study, the effect of surface ionization on the CDI efficiencies of Fe-, Co-, and Ni-doped α-MnO2 (<0.1 mol %) as a model cathode material was studied. A pattern that CDI efficiency decreased with increasing negative surface charge density resulting from surface deprotonation was noted. This is likely attributed to the appreciable co-ion expulsion occurring at a highly ionized surface in the mesopores of MnO2. It is thus concluded that the combination of surface charge modification and a microporous environment would be important for CDI efficiency enhancement by minimizing co-ion exclusion effect. In the former case, structural stress adjustment by doping elements would be a practical route to regulate the p Ka1 and p Ka2 values and consequently the degree of surface ionization of MnO2.

3.
Environ Toxicol ; 32(6): 1742-1753, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28181394

RESUMO

Silver nanoparticles (AgNPs) are commonly used nanomaterials in consumer products. Previous studies focused on its effects on neurons; however, little is known about their effects and uptake mechanisms on glial cells under normal or activated states. Here, ALT astrocyte-like, BV-2 microglia and differentiated N2a neuroblastoma cells were directly or indirectly exposed to 10 nm AgNPs using mono- and co-culture system. A lipopolysaccharide (LPS) was pretreated to activate glial cells before AgNP treatment for mimicking NP exposure under brain inflammation. From mono-culture, ALT took up the most AgNPs and had the lowest cell viability within three cells. Moreover, AgNPs induced H2 O2 and NO from ALT/activated ALT and BV-2, respectively. However, AgNPs did not induce cytokines release (IL-6, TNF-α, MCP-1). LPS-activated BV-2 took up more AgNPs than normal BV-2, while the induction of ROS and cytokines from activated cells were diminished. Ca2+ -regulated clathrin- and caveolae-independent endocytosis and phagocytosis were involved in the AgNP uptake in ALT, which caused more rapid NP translocation to lysosome than in macropinocytosis and clathrin-dependent endocytosis-involved BV-2. AgNPs directly caused apoptosis and necrosis in N2a cells, while by indirect NP exposure to bottom chamber ALT or BV-2 in Transwell, more apoptotic upper chamber N2a cells were observed. Cell viability of BV-2 also decreased in an ALT-BV-2 co-culturing study. The damaged cells correlated to NP-mediated H2 O2 release from ALT or NO from BV-2, which indicates that toxic response of AgNPs to neurons is not direct, but indirectly arises from AgNP-induced soluble factors from other glial cells.


Assuntos
Astrócitos/efeitos dos fármacos , Endocitose/efeitos dos fármacos , Lisossomos/metabolismo , Nanopartículas Metálicas/toxicidade , Microglia/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Prata/toxicidade , Animais , Apoptose/efeitos dos fármacos , Astrócitos/imunologia , Astrócitos/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Cocultura , Interleucina-6/metabolismo , Lipopolissacarídeos/farmacologia , Camundongos , Microglia/imunologia , Microglia/metabolismo , Necrose , Neurônios/imunologia , Neurônios/metabolismo , Fagocitose/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo
4.
Phys Chem Chem Phys ; 18(42): 29300-29307, 2016 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-27731868

RESUMO

Passivation of surface states is known to reduce the onset photocurrent potential by removing the Fermi level pinning effect at the Helmholtz layer and enhance the photocurrent plateau by suppressing recombination loss in the space charge region. We report for the first time that metal ions can effectively passivate surface states in situ that improves the photoelectrochemical (PEC) performance of hematite electrodes. Among metal ions studied, Cr(iii), Mn(ii), Fe(ii), Co(ii), Cu(ii) and Zn(ii) were found to enhance the photocurrent by 30-300%; whereas photocurrent density significantly dropped by 90% in Ni(ii) solution after 90 min of illumination. We further hypothesized that the surface states might be the high affinity adsorption sites on hematite surfaces. Once the surface states are occupied by metal ions, along with the Schottky barrier effect at the hematite/electrolyte interface formed by adsorbed metal ions, the PEC performance is enhanced. Our results also enable the design of a potential PEC based water treatment method to extract additional energy, for example, in the brines (containing concentrated metal ions and electrolyte) of membrane processed wastewater.

5.
Environ Monit Assess ; 188(3): 180, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26899028

RESUMO

The elemental content of fish scales is known to be a reliable biogeochemical tag for tracing the origin of fishes. In this study, this correlation is further confirmed to exist on the surface of fish scales using a novel environmental analytical method, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), which bypasses several complicated sample preparation procedures such as acid digestion and pre-concentration. The results suggest that the elemental ratios of Sr/Ca, Ba/Ca, and Mn/Ca on the surface of fish scales are strongly correlated with the geochemical environment of their original habitat. This correlation is further demonstrated to be sensitive to variation of water in the habitat due to the adsorbed inorganic ions. In this sense, the limitation of fish scales as a biogeochemical tag is the sensitivity of LA-ICP-MS toward the studied elements. Graphical abstract Illustration of the connection between element distribution pattern over the surface of fish scales and biogeochemical environment of its habitat.


Assuntos
Ecossistema , Monitoramento Ambiental/métodos , Peixes/metabolismo , Oligoelementos/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Meio Ambiente , Espectrometria de Massas , Oligoelementos/análise , Poluentes Químicos da Água/análise
6.
Environ Sci Technol ; 49(6): 3813-21, 2015 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-25692749

RESUMO

The so-called "Trojan-horse" mechanism, in which nanoparticles are internalized within cells and then release high levels of toxic ions, has been proposed as a behavior in the cellular uptake of Ag nanoparticles (AgNPs). While several reports claim to have proved this mechanism by measuring AgNPs and Ag ions (I) in cells, it cannot be fully proven without examining those two components in both intra- and extracellular media. In our study, we found that even though cells take up AgNPs similarly to (microglia (BV-2)) or more rapidly than (astrocyte (ALT)) Ag (I), the ratio of AgNPs to total Ag (AgNPs+Ag (I)) in both cells was lower than that in outside media. It could be explained that H2O2, a major intracellular reactive oxygen species (ROS), reacts with AgNPs to form more Ag (I). Moreover, the major speciation of Ag (I) in cells was Ag(cysteine) and Ag(cysteine)2, indicating the possible binding of monomer cysteine or vital thiol proteins/peptides to Ag ions. Evidence we found indicates that the Trojan-horse mechanism really exists.


Assuntos
Endocitose , Espaço Extracelular/química , Espaço Intracelular/química , Nanopartículas Metálicas/química , Prata/metabolismo , Animais , Ácido Ascórbico/química , Morte Celular/efeitos dos fármacos , Linhagem Celular , Meios de Cultura , Endocitose/efeitos dos fármacos , Peróxido de Hidrogênio/química , Íons , Lipopolissacarídeos/química , Camundongos , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Prata/toxicidade
7.
Environ Res ; 136: 253-63, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25460644

RESUMO

Silver nanoparticles (AgNPs) have antibacterial characteristics, and currently are applied in Ag-containing products. This study found neural cells can uptake 3-5 nm AgNPs, and investigated the potential effects of AgNPs on gene expression of inflammation and neurodegenerative disorder in murine brain ALT astrocytes, microglial BV-2 cells and neuron N2a cells. After AgNPs (5, 10, 12.5 µg/ml) exposure, these neural cells had obviously increased IL-1ß secretion, and induced gene expression of C-X-C motif chemokine 13 (CXCL13), macrophage receptor with collagenous structure (MARCO) and glutathione synthetase (GSS) for inflammatory response and oxidative stress neutralization. Additionally, this study found amyloid-ß (Aß) plaques for pathological feature of Alzheimer's disease (AD) deposited in neural cells after AgNPs treatment. After AgNPs exposure, the gene expression of amyloid precursor protein (APP) was induced, and otherwise, neprilysin (NEP) and low-density lipoprotein receptor (LDLR) were reduced in neural cells as well as protein level. These results suggested AgNPs could alter gene and protein expressions of Aß deposition potentially to induce AD progress in neural cells. It's necessary to take notice of AgNPs distribution in the environment.


Assuntos
Encéfalo/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Inflamação/genética , Nanopartículas Metálicas , Prata/química , Animais , Encéfalo/citologia , Camundongos
8.
Anal Bioanal Chem ; 401(3): 909-15, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21667060

RESUMO

In this study, we employed laser ablation/inductively coupled plasma mass spectrometry (LA-ICP-MS) to map the spatial distribution of Gd-doped iron oxide nanoparticles (IONPs) in one tumor slice that had been subjected to magnetic fluid hyperthermia (MFH). The mapping results revealed the high resolution of the elemental analysis, with the distribution of Gd atoms highly correlated with that of the Fe atoms. The spatial distributions of C, P, S, and Zn atoms revealed that the effect of MFH treatment was significantly dependent on the diffusion of the magnetic fluid in the tissue. An observed enrichment of Cu atoms after MFH treatment was probably due to inflammation in the tumor. The abnormal distribution of Ni atoms suggests a probable biochemical reaction in the tumor. Therefore, this LA-ICP-MS mapping technique can provide novel information regarding the spatial distribution of elements in tumors after cancer therapy.


Assuntos
Elementos Químicos , Terapia a Laser , Espectrometria de Massas , Metais Pesados/química , Neoplasias/química , Neoplasias da Próstata/química , Animais , Linhagem Celular Tumoral , Compostos Férricos/química , Gadolínio/química , Temperatura Alta , Humanos , Masculino , Nanopartículas Metálicas/química , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias/diagnóstico por imagem , Neoplasias/ultraestrutura , Neoplasias da Próstata/diagnóstico por imagem , Radiografia , Coloração e Rotulagem
9.
Sci Total Environ ; 675: 31-40, 2019 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-31026641

RESUMO

MnO2 is a common material for the fabrication and design of capacitive deionization (CDI) devices but there is little information on the role of MnO2 crystal phase on CDI performance. A series of MnO2 (α, ß, γ, and δ phase) were synthesized and fabricated as cathodes for studying the CDI performance as affected by pH in simple batch mode experiments. Our results revealed that the deionization efficiency decreased with increased negative surface charge as a result of the deprotonated surface. Importantly, this correlation was pH independent and the surface heterogeneity due to different MnO2 phase was likely responsible for the different degree of surface ionization and consequently the CDI efficiency. Results of electrochemical impedance spectroscopy analyses further implicated that a highly ionized surface would result in a diffusion layer with a great resistance that conversely inhibited the access of co-ions in the CDI process. This indicated the applied potential was mainly responsible for driving ions transporting through the double layer resistance instead of accommodating them (electrosorption). Based on our results, the surface heterogeneity as a result of different spatially distributed MnO6 octahedral would be accounted for the varying degree of surface ionization and consequently the discrepancy in CDI efficiency among different MnO2 phases.

10.
ACS Appl Mater Interfaces ; 11(12): 11144-11156, 2019 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-30883079

RESUMO

Boron neutron capture therapy (BNCT) is a promising radiotherapy for treating glioblastoma multiforme (GBM). However, the penetration of drugs (e.g., sodium borocaptate and BSH) for BNCT into brain tumors is limited by cerebral vesicular protective structures, the blood-brain barrier, and the blood-brain tumor barrier (BTB). Although BSH has been reported to be selectively taken up by tumors, it is rapidly excreted from the body and cannot achieve a high tumor-to-normal brain ratio (T/N ratio) and tumor-to-blood ratio (T/B ratio). Despite the development of large-molecular weight boron compounds, such as polymers and nanoparticles, to enhance the permeation and retention effect, their effects remain insufficient for clinical use. To improve the efficiency of boron delivery to the tumor site, we propose combinations of self-assembled boron-containing polyanion [polyethylene glycol- b-poly(( closo-dodecaboranyl)thiomethylstyrene) (PEG- b-PMBSH)] nanoparticles (295 ± 2.3 nm in aqueous media) coupled with cationic microbubble (B-MB)-assisted focused ultrasound (FUS) treatment. Upon FUS sonication (frequency = 1 MHz, pressure = 0.3-0.7 MPa, duty cycle = 0.5%, sonication = 1 min), B-MBs can simultaneously achieve safe BTB opening and boron drug delivery into tumor tissue. Compared with the MBs of the PEG- b-PMBSH mixture group (B + MBs), B-MBs showed 3- and 2.3-fold improvements in the T/N (4.4 ± 1.4 vs 1.3 ± 0.1) and T/B ratios (1.4 ± 0.6 vs 0.1 ± 0.1), respectively, after 4 min of FUS sonication. The spatial distribution of PEG- b-PMBSH was also improved by the complex of PEG- b-PMBSH with MBs. The findings presented herein, in combination with the expanding clinical application of FUS, may improve BNCT and treatment of GBM.


Assuntos
Terapia por Captura de Nêutron de Boro , Boro/química , Microbolhas , Polímeros/química , Animais , Barreira Hematoencefálica/metabolismo , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/radioterapia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Glioma/patologia , Glioma/radioterapia , Humanos , Bicamadas Lipídicas/química , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas/química , Sonicação , Distribuição Tecidual
11.
Sci Total Environ ; 399(1-3): 128-46, 2008 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-18485452

RESUMO

The aerosol in the Taipei basin is difficult to transport outward under specific weather patterns owing to complex terrain blocking. In this study, seven weather patterns are identified from synoptic weather maps for aerosol events, which occurred from March 2002 to February 2005. Among the identified weather patterns, High Pressure Peripheral Circulation (HPPC), Warm area Ahead of a cold Front (WAF), TYPhoon (TYP), Pacific High Pressure system stretching westerly (PHP), Weak High Pressure system (WHP), and Weak Southern Wind (WSW) are related to terrain blocking. The remaining pattern is High Pressure system Pushing (HPP). The classification of the pollution origin of the air masses shows that 15% of event days were contributed by long-range transport (LRT), 20% by local pollution (LP), and 65% by LRT/LP mix. Terrain blocking causes aerosol accumulation from high atmospheric stability and weak winds occurring under HPPC, TYP, and PHP weather patterns when the Taipei basin is situated on the lee side of the Snow Mountains Chain (SMC). Terrain blocking also occurs when the Taipei basin is situated on the upwind of SMC and Mt. Da-Twen under WAF and WSW patterns. To study the variation of aerosol properties under the mixed influence of terrain and pollution origin, we conducted a field observation simultaneously at the urban, suburban, and background sites in the Greater Taipei area from April 14 to 23, 2004. Terrain blocking plays an important role in aerosol accumulation in the stagnant environment when the Taipei basin is on the lee side of SMC. On the other hand, the PM(2.5) sulfate level is stable with a fraction of 30% in PM(2.5) during the observation period at the urban (25%-33%) and background (25%-41%) sites. It indicates that background PM(2.5) sulfate is high on the West Pacific in winter.


Assuntos
Aerossóis/análise , Movimentos do Ar , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Aerossóis/química , Poluentes Atmosféricos/química , Desastres , Geografia , Tamanho da Partícula , Material Particulado , Estações do Ano , Taiwan , Fatores de Tempo , Tempo (Meteorologia)
12.
Appl Radiat Isot ; 66(6-7): 976-80, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18359235

RESUMO

The two-dimensional extrapolation technique and dead time extrapolation technique of 4pibeta-gamma-coincidence counting were used to standardize the activity of (67)Ga. The counting results of the two absolute counting techniques showed good agreement while the two-dimensional extrapolation technique could save about 50% of the total counting time in this study. The accuracy of the Capintec CRC-15R radionuclide calibrator used by the radiopharmacy of INER was studied in this research. A new calibration setting number, 99, was recommended to the radiopharmacy of INER in the Bayer 10mL sterile empty vial geometry.


Assuntos
Radioisótopos de Gálio/normas , Compostos Radiofarmacêuticos/normas , Padrões de Referência
13.
ACS Appl Mater Interfaces ; 10(38): 32736-32746, 2018 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-30180542

RESUMO

Energy consumption is always a major issue hindering the universal application of membrane-based filtration system. We herein demonstrated a low-energy-consumption microfiltration system that can be operated under ambient pressure while a great metal ion rejection rate (>95%) accompanied by a high permeate flux (100 L/m2h) was concurrently reached. This achievement was closely correlated to the enhanced metal ion adsorption by grafted carboxyl groups at the cellulose filter paper through esterification. Adsorbed metal ions consequently enhanced Donnan exclusion effect and therefore high rejection rate was achieved. Rejection rate of modified membrane was strongly correlated to the formation constant of associated carboxyl group to metal ions. Our results would be important for developing low-energy-consumption filtration systems for water and wastewater treatment application.

14.
J Hazard Mater ; 144(1-2): 52-8, 2007 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-17118542

RESUMO

In this study, artificial lightweight aggregate (LWA) manufactured from recycled resources was investigated. Residues from mining, fly ash from an incinerator and heavy metal sludge from an electronic waste water plant were mixed into raw aggregate pellets and fed into a tunnel kiln to be sintered and finally cooled rapidly. Various feeding and sintering temperatures were employed to examine their impact on the extent of vitrification on the aggregate surface. Microstructural analysis and toxicity characteristic leaching procedure (TCLP) were also performed. The results show that the optimum condition of LWA fabrication is sintering at 1150 degrees C for 15 min with raw aggregate pellets fed at 750 degrees C. The rapidly vitrified surface envelops the gas produced with the increase in internal temperature and cooling by spraying water prevents the aggregates from binding together, thus forming LWA with specific gravity of 0.6. LWA produced by sintering in tunnel kiln shows good vitrified surface, low water absorption rate below 5%, and low cylindrical compressive strength of 4.3 MPa. In addition, only trace amounts of heavy metals were detected, making the LWA non-hazardous for construction use.


Assuntos
Conservação dos Recursos Naturais , Materiais de Construção , Resíduos Industriais , Silicatos de Alumínio , Bentonita , Carbono , Argila , Cinza de Carvão , Eletrônica , Temperatura Alta , Incineração , Metais Pesados/análise , Mineração , Material Particulado , Esgotos , Gerenciamento de Resíduos/métodos
15.
J Hazard Mater ; 149(1): 180-8, 2007 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-17478037

RESUMO

A sequential extraction method has been applied for the determination of binding forms of trace elements in the municipal solid waste incineration (MSWI) fly ash and evaluating their leaching behavior in view of their potential environmental impact. The elemental determinations in the different leachates are performed by ICP-AES and ICP-MS, respectively. The morphology and mineralogical phases after extraction step were performed by scanning electron microscopy (SEM). Total of 20 elements in the samples are investigated. A reference material of city waste incineration fly ash (BCR No. 176) is also tested to examine the applicability as well as accuracy of the proposed method. The sum of most elements present in the individual fractions shows a good agreement with the total elemental concentrations. The extraction efficiencies are generally higher than 80% except for that of Cr and V. The extractable data of most elements give information about the binding forms of various elements in both incineration fly ashes. It was found that the elements such as Ca, K, Na, Pb, Zn, Cd, Cu and Sr have exhibited a remarkable mobility in fly ash. More than half of them would be dissolved or exchanged under a mild leaching condition. The toxic elements such as Pb, Cd, Zn and Cu have a great potential to be released into the environment under normal conditions.


Assuntos
Carbono/química , Incineração , Metais/análise , Material Particulado/química , Poluentes Químicos da Água/análise , Carbono/análise , Fracionamento Químico , Cinza de Carvão , Espectrometria de Massas , Material Particulado/análise , Espectrofotometria Atômica
16.
J Hazard Mater ; 146(1-2): 98-105, 2007 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-17222508

RESUMO

Metal sludge from industrial wastewater treatment plants was mixed with mining residues to be recycled into lightweight aggregate (LWA) through sintering at different temperatures. The physical properties of the LWA thus obtained were examined by scanning electron microscopy analyzer (SEM) coupled with an energy dispersive X-ray analyzer (EDX). The sequential extraction method combined with inductively coupled plasma atomic emission spectrometry (ICP-AES) was employed to determine the concentration and distribution of hazardous toxic elements in the metal sludge-based artificial LWA. The results show that the leaching concentrations of Cd, Cr, Cu, and Pb present in the non-sintered raw aggregate pellets reached 7.4, 68.0, 96.0, and 61.4 mg/l, respectively, far exceeding the regulatory threshold. Sintering at 1150 degrees C for 15 min results in stronger chemical bonds being formed between the elements. Hence, after the first three steps of sequential extraction, the concentrations of Cr, Cu, and Pb reached 2.69, 1.50, and 1.88 mg/l at 1150 degrees C, while the final residues had total concentrations of 96.1, 88.4, and 60.6 mg/kg, respectively, with Cd undetected in both phases. The concentration levels fell within the regulatory threshold, indicating that the LWA fabricated from recycled metal sludge contains elements that are toxic and hazardous but not leached. Having no harmful effect on the environment, the metal sludge-based artificial LWA is not only safe but also practical with good physical properties.


Assuntos
Materiais de Construção/análise , Metais Pesados/análise , Conservação dos Recursos Naturais , Poluentes Ambientais/análise , Temperatura Alta , Resíduos Industriais/análise , Porosidade , Esgotos
17.
Appl Radiat Isot ; 64(10-11): 1380-3, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16556500

RESUMO

The Institute of Nuclear Energy Research (INER) has provided 188Re radiopharmaceuticals for hospitals in Taiwan. To enhance the accuracy of commercial radionuclide calibrators used by radiopharmacies and hospitals, and to ensure that patients receive proper doses of these radiopharmaceuticals, it is very important to standardize this nuclide. The 4pibeta-gamma coincidence counting method was used to standardize the mass activities of 188Re in this study. At the same time, three well type ionization chambers, Centronic IG11-N20, Centronic IG11-A20, and ISOCAL-IV, were calibrated by the standardized solutions of the nuclide. In this research, the calibration figures of ISOCAL-IV for the nuclide were consistent with the results of National Physical Laboratory (NPL, UK). The outcome implied that the results of coincidence counting did mutually agree. On the other hand, the radionuclide calibrator in the radiopharmacy was producing measurement errors of about 20% when using the manufacturers recommended calibration setting: an accurate correction factor has now been determined in this study.


Assuntos
Radioisótopos/análise , Radioisótopos/normas , Radiometria/métodos , Compostos Radiofarmacêuticos/análise , Compostos Radiofarmacêuticos/normas , Rênio/análise , Rênio/normas , Doses de Radiação , Radiometria/normas , Padrões de Referência , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrometria gama/métodos , Espectrometria gama/normas , Taiwan
18.
Chem Biol Interact ; 254: 34-44, 2016 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-27216632

RESUMO

Although, titanium dioxide nanoparticles (TiO2NPs) are nanomaterials commonly used in consumer products, little is known about their hazardous effects, especially on central nervous systems. To examine this issue, ALT astrocyte-like, BV-2 microglia and differentiated N2a neuroblastoma cells were exposed to 6 nm of 100% anatase TiO2NPs. A lipopolysaccharide (LPS) was pre-treated to activate glial cells before NP treatment for mimicking NP exposure under brain injury. We found that ALT and BV-2 cells took up more NPs than N2a cells and caused lower cell viability. TiO2NPs induced IL-1ß in the three cell lines and IL-6 in N2a. LPS-activated BV-2 took up more TiO2NPs than normal BV-2 and released more intra/extracellular reactive oxygen species (ROS), IL-1ß, IL-6 and MCP-1 than did activated BV-2. Involvement of clathrin- and caveolae-dependent endocytosis in ALT and clathrin-dependent endocytosis and phagocytosis in BV-2 both had a slow NP translocation rate to lysosome, which may cause slow ROS production (after 24 h). Although TiO2NPs did not directly cause N2a viability loss, by indirect NP exposure to the bottom chamber of LPS-activated BV-2 in the Transwell system, they caused late apoptosis and loss of cell viability in the upper N2a chamber due to H2O2 and/or TNF-α release from BV-2. However, none of the adverse effects in N2a or BV-2 cells was observed when TiO2NPs were exposed to ALT-N2a or ALT-BV-2 co-culture. These results demonstrate that neuron damage can result from TiO2NP-mediated ROS and/or cytokines release from microglia, but not from astrocytes.


Assuntos
Apoptose/efeitos dos fármacos , Comunicação Celular/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Titânio/química , Animais , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Cocultura , Endocitose/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Lipopolissacarídeos/toxicidade , Lisossomos/metabolismo , Nanopartículas Metálicas/química , Camundongos , Microglia/citologia , Microglia/efeitos dos fármacos , Microglia/metabolismo , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Óxido Nítrico/metabolismo , Fagocitose/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
19.
J Colloid Interface Sci ; 466: 28-35, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26704473

RESUMO

The consideration of water energy nexus inspires the environmental engineering community to pursue a more sustainable strategy in the wastewater treatment. One potential response would be to enhance the performance of the low-pressure driven filtration system. To reach this objective, it is essential to have a better understanding regarding the surface interaction between the target substance and the surface of membrane. In this study, the hollow fiber ceramic membranes were coated with a goethite layer in order to enhance the Co(2+) rejection. Experimental results indicate that higher Co(2+) rejections are always accompanied with the significant reduction in the permeability. Based on the consideration of electroviscous effect, the surface interactions including the induced changes in viscosity, pore radius and Donnan effect in the goethite layer are likely responsible for the pH dependent behaviors in the rejection and permeability. These results could be valuable references to develop the filtration system with high rejection along with acceptable degree of permeability in the future.

20.
J Air Waste Manag Assoc ; 55(8): 1236-44, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16187593

RESUMO

Road dust contributes a large percentage of the atmosphere's suspended particles in Taiwan. Three road dust samples were collected from downtown, electrical park, and freeway tunnel areas. A mechanical sieve separated the road dust in the initial stage. Particles > 100 microm were 75%, 70%, and 60% (wt/wt), respectively, of the samples. Those particles < 37 microm were resuspended in another mixing chamber and then collected by a Moudi particle sampler. The largest mass fraction of resuspended road dust was in the range of 1-10 microm. Ultrafine particles (< 1 microm) composed 33.7, 17, and 7.4% of the particle samples (downtown, electrical park, and freeway tunnel, respectively). The road dust compositions were analyzed by inductively coupled plasma (ICP)-atomic emissions spectroscopy and ICP-mass spectrometry. The highest concentration fraction contained more aluminum (Al), iron (Fe), calcium (Ca), and potassium than other elements in the road dust particle samples. Additionally, the sulfur (S) content in the road dust from the electrical park and freeway tunnel areas was 2.1 and 3.4 times the downtown area sample, respectively. The sulfur originated from the vehicle and boiler oil combustion and industrial manufacturing processes. Furthermore, zinc (Zn) concentration in the tunnel dust was 2.6 times that of the downtown and electrical park samples, which can be attributed to vehicle tire wear and tear. Resuspended road dusts (< 10 microm) from the downtown and freeway tunnel areas were principally 2.5-10 microm Al, barium (Ba), Ca, copper (Cu), Fe, magnesium (Mg), sodium (Na), antimony (Sb), and Zn, whereas arsenic (As), chromium (Cr), and nickel (Ni) were predominant in the ultrafine particle samples (< 1 microm). Al, Ba, and Ca are the typical soil elements in coarse particles; and As, and Cr and Ni are the typical fingerprint of oil combustion and vehicle engine abrasion in ultrafine particles. There was a special characteristic of resuspension road dust at electrical park, that is, many elements, including As, Ba, Ca, cadmium, Cr, Cu, Fe, manganese (Mn), Ni, lead (Pb), S, vanadium (V), and Zn, were major in ultrafine particles. These elements should be attributed to the special manufacturing processes of electric products.


Assuntos
Poluentes Atmosféricos/análise , Poeira/análise , Metais/análise , Eletricidade , Monitoramento Ambiental , Combustíveis Fósseis , Cromatografia Gasosa-Espectrometria de Massas , Tamanho da Partícula , Espectrofotometria Atômica , Taiwan , Emissões de Veículos
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