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1.
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.

2.
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
3.
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.

4.
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.

5.
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
6.
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.

7.
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
8.
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
9.
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.

10.
J Environ Radioact ; 150: 62-7, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26295438

RESUMO

It is important that monitoring environmental tritiated water for understanding the contamination dispersion of the nuclear facilities. Tritium is a pure beta radionuclide which is usually measured by Liquid Scintillation Counting (LSC). The average energy of tritum beta is only 5.658 keV that makes the LSC counting of tritium easily be interfered by the beta emitted by other radionuclides. Environmental tritiated water samples usually need to be decontaminated by distillation for reducing the interference. After Fukushima Nucleaer Accident, the highest gross beta concentration of groundwater samples obtained around Fukushima Daiichi Nuclear Power Station is over 1,000,000 Bq/l. There is a need for a distillation with ultra-high decontamination efficiency for environmental tritiated water analysis. This study is intended to improve the heating temperature control for better sub-boiling distillation control and modify the height of the container of the air cooling distillation device for better fractional distillation effect. The DF of Cs-137 of the distillation may reach 450,000 which is far better than the prior study. The average loss rate of the improved method and device is about 2.6% which is better than the bias value listed in the ASTM D4107-08. It is proven that the modified air cooling distillation device can provide an easy-handling, water-saving, low cost and effective way of purifying water samples for higher beta radionuclides contaminated water samples which need ultra-high decontamination treatment.


Assuntos
Descontaminação/métodos , Destilação/métodos , Monitoramento de Radiação/métodos , Trítio/análise , Poluentes Radioativos da Água/análise , Purificação da Água/instrumentação , Purificação da Água/métodos , Descontaminação/instrumentação , Destilação/instrumentação , Acidente Nuclear de Fukushima , Água Subterrânea/análise , Japão , Monitoramento de Radiação/instrumentação
11.
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
12.
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
13.
J Hazard Mater ; 270: 92-101, 2014 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-24553353

RESUMO

In this paper, we demonstrate a means of simultaneously solving two serious environmental issues by reutilization of calcinated mixture of pulverized waste oyster shells blending with poly(methyl methacrylate) (PMMA) nanospheres to prepare CaO-based sorbents for CO2 capture. After 10 cycles of isothermal carbonation/calcination at 750°C, the greatest CO2 uptake (0.19 g CO2/g sorbent) was that for the sorbent featuring 70 wt% of PMMA, which was almost three times higher than that (0.07 g CO2/g sorbent) of untreated waste oyster shell. The greater CO2 uptake was likely a result of particle size reduction and afterwards surface basicity enhancement and an increase in the volume of mesopores and macropores. Following simplified life cycle assessment, whose all input values were collected from our experimental results, suggested that a significant CO2 emission reduction along with lesser human health and ecosystems impacts would be achieved immediately once waste is reutilized. Most importantly, the CO2 uptake efficiency must be greater than 20% or sorbents prepared from limestone mining would eventually produce a net positive CO2 emission.


Assuntos
Poluentes Atmosféricos/química , Exoesqueleto , Compostos de Cálcio/química , Dióxido de Carbono/química , Nanosferas/química , Óxidos/química , Polimetil Metacrilato/química , Adsorção , Animais , Sequestro de Carbono , Ostreidae , Tamanho da Partícula , Reciclagem , Propriedades de Superfície , Gerenciamento de Resíduos/métodos , Resíduos
14.
Health Phys ; 106(2 Suppl 1): S34-41, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24378562

RESUMO

After the 9/11 incident, the needs of environmental survey mobility were increased because the time and place of terrorism attacks are more unpredictable than traditional radiological and nuclear accident. In recent years, more and more attention has been paid to the radiation protection of the survey workers in the field. The Institute of Nuclear Energy Research has established a Mobile Environmental Survey System (MESS) for real time emergency response by using network communication. The system consists of three major functional components: the mobile units, the management center, and the work stations. The system can display real time survey data on an electric map collected by the survey workers from the remote field to improve the environmental survey mobility. The system can also send the survey workers messages/warnings according to geographic information and the location of the mobile unit to keep them from unnecessary radiation exposure that may be an effective way to the goal of "as low as reasonably achievable" for environmental surveys. MESS has been adopted as an essential tool for emergency response in Taiwan. The application experience of MESS in the relative exercises will be discussed in this paper.


Assuntos
Coleta de Dados , Emergências , Socorristas , Sistemas de Informação Geográfica , Bases de Dados Factuais , Humanos , Segurança , Fatores de Tempo
15.
ACS Appl Mater Interfaces ; 5(16): 7937-49, 2013 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-23865744

RESUMO

It has been suggested that a high concentration of Fe(3+) in solution, a low pH, and noncomplexing ions of high ionic strength are all essential for developing a high-quality hematite array. Our curiosity was piqued regarding the role of the electrolyte ions in the hydrothermal synthesis of hematite photoanodes. In this study, we prepared hematite photoanodes hydrothermally from precursor solutions of 0.1 M FeCl3 at pH 1.55 with a background electrolyte of 1.0 M sodium halide (NaF, NaCl, NaBr, or NaI). We compared the structures and properties of the as-obtained hematite photoanodes with those of the material prepared in 1.0 M NaNO3, the most widely adopted electrolyte in previous studies. Among our studied systems, we found that the hematite photoanode prepared in NaCl solution was the only one possessing properties similar to those of the sample obtained from the NaNO3 solution-most importantly in terms of photoelectrochemical performance (ca. 0.2 mA/cm(2) with +0.4 V vs SCE). The hematites obtained from the NaF, NaBr, and NaI solutions exhibited much lower (by approximately 2 orders of magnitude) photocurrent densities under the same conditions, possibly because of their relatively less ordered crystallinity and the absence of rodlike morphologies. Because the synthetic protocol was identical in each case, we believe that these two distinct features reflect the environments in which these hematite photoanodes were formed. Consistent with the latest studies reported in the literature of the X-ray photoelectron spectra of fast-frozen hematite colloids in aqueous solutions, it appears that the degree of surface ion loading at the electrolyte-hematite interface (Stern layer) is critical during the development of hematite photoanodes. We suspect that a lower ion surface loading benefits the hematite developing relatively higher-order and a rodlike texture, thereby improving the photoelectrochemical activity.


Assuntos
Eletrodos , Compostos Férricos/química , Brometos/química , Catálise , Compostos Férricos/síntese química , Cloreto de Sódio/química , Compostos de Sódio/química , Fluoreto de Sódio/química , Iodeto de Sódio/química
16.
Appl Radiat Isot ; 81: 272-5, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23631797

RESUMO

Institute of Nuclear Energy Research (INER) has designed an air-cooling distillation device and got a US patent. The decontamination factor (60)Co and (137)Cs is above 23,000. Tritium loss rate is one of testing items in ASTM D4107 Standard Test Method for Tritium in Drinking Water. In this study, the 3 levels (high, middle and low level) of tritium concentration of testing samples for the loss rate test were prepared similar to the concentrations reported in ASTM D4107. The loss rate of the high level is -2.37%, the middle is -2.31% and the low level is -2.47%. These results show that the air-cooling distillation device has good performance in the environmental water tritium analysis work.


Assuntos
Descontaminação/instrumentação , Destilação/instrumentação , Monitoramento de Radiação/instrumentação , Trítio/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Água/análise , Água/química , Desenho de Equipamento , Análise de Falha de Equipamento , Doses de Radiação , Manejo de Espécimes/instrumentação
17.
J Agric Food Chem ; 61(21): 5009-15, 2013 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-23646931

RESUMO

In this study, the laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was adopted to determine the distribution of inorganic elements, including Ca, Cu, Fe, Mg, Mn, S, P, Pb, and Zn, in honeybees (Apis melifera L.). Two features are particularly noteworthy. First, it was found there is a significant amount of Fe located at the fringe of the abdomen in worker bees; ultrasonic imaging, scanning electron microscopy, and magnetic resonance imaging revealed that it arose from magnetic Fe-bearing nanoparticles (NPs) having an average diameter of approximately 40 nm. Interestingly, only worker bees contained these magnetic Fe-bearing NPs; no similar features appeared in larvae, pupae, wasps, or drones. Second, a detectable amount of Pb accumulated particularly in the alimentary canals of worker bees. Again, no detectable amounts of Pb in larvae, pupae, drones, or wasps, yet a level of 0.24 ± 0.05 mg/kg of Pb in pollen; therefore, the diet appears to be the primary pathway for environmental pollutants entering the honeybees' food chain.


Assuntos
Abelhas/química , Abelhas/fisiologia , Poluentes Ambientais/análise , Comportamento Alimentar , Metais/análise , Animais , Poluentes Ambientais/metabolismo , Terapia a Laser , Espectrometria de Massas , Metais/metabolismo
18.
Anal Bioanal Chem ; 404(10): 3025-36, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23052863

RESUMO

Understanding the cytotoxicity of quantum dots strongly relies upon the development of new analytical techniques to gather information about various aspects of the system. In this study, we demonstrate the in vivo biodistribution and fate of CdSe quantum dots in the murine model by means of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). By comparing the hot zones of each element acquired from LA-ICP-MS with those in fluorescence images, together with hematoxylin and eosin-stained images, we are able to perceive the fate and in vivo interactions between quantum dots and rat tissues. One hour after intravenous injection, we found that all of the quantum dots had been concentrated inside the spleen, liver and kidneys, while no quantum dots were found in other tissues (i.e., muscle, brain, lung, etc.). In the spleen, cadmium-114 signals always appeared in conjunction with iron signals, indicating that the quantum dots had been filtered from main vessels and then accumulated inside splenic red pulp. In the liver, the overlapped hot zones of quantum dots and those of phosphorus, copper, and zinc showed that these quantum dots have been retained inside hepatic cells. Importantly, it was noted that in the kidneys, quantum dots went into the cortical areas of adrenal glands. At the same time, hot zones of copper appeared in proximal tubules of the cortex. This could be a sign that the uptake of quantum dots initiates certain immune responses. Interestingly, the intensity of the selenium signals was not proportional to that of cadmium in all tissues. This could be the result of the decomposition of the quantum dots or matrix interference. In conclusion, the advantage in spatial resolution of LA-ICP-MS is one of the most powerful tools to probe the fate, interactions and biodistribution of quantum dots in vivo.


Assuntos
Compostos de Cádmio/farmacocinética , Terapia a Laser , Espectrometria de Massas , Pontos Quânticos , Compostos de Selênio/farmacocinética , Animais , Rim/ultraestrutura , Terapia a Laser/métodos , Fígado/ultraestrutura , Espectrometria de Massas/métodos , Camundongos , Microscopia de Fluorescência , Baço/ultraestrutura , Distribuição Tecidual
19.
J Hazard Mater ; 195: 107-14, 2011 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-21889848

RESUMO

Carbon dioxide (CO(2)) sequestration experiments using the accelerated carbonation of three types of steelmaking slags, i.e., ultra-fine (UF) slag, fly-ash (FA) slag, and blended hydraulic slag cement (BHC), were performed in an autoclave reactor. The effects of reaction time, liquid-to-solid ratio (L/S), temperature, CO(2) pressure, and initial pH on CO(2) sequestration were evaluated. Two different CO(2) pressures were chosen: the normal condition (700 psig) and the supercritical condition (1300 psig). The carbonation conversion was determined quantitatively by using thermo-gravimetric analysis (TGA). The major factors that affected the conversion were reaction time (5 min to 12h) and temperature (40-160°C). The BHC was found to have the highest carbonation conversion of approximately 68%, corresponding to a capacity of 0.283 kg CO(2)/kg BHC, in 12h at 700 psig and 160°C. In addition, the carbonation products were confirmed to be mainly in CaCO(3), which was determined by using scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) to analyze samples before and after carbonation. Furthermore, reaction kinetics were expressed with a surface coverage model, and the carbon footprint of the developed technology in this investigation was calculated by a life cycle assessment (LCA).


Assuntos
Dióxido de Carbono/química , Carbono/química , Materiais de Construção , Aço , Temperatura Alta , Cinética , Microscopia Eletrônica de Varredura
20.
Talanta ; 85(2): 983-90, 2011 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-21726728

RESUMO

This paper describes a simple method for simultaneous preconcentration and matrix reduction during the analysis of rare earth elements (REEs) in water samples through laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). From a systematic investigation of the co-precipitation of REEs using magnesium hydroxide, we optimized the effects of several parameters - the pH, the amount of magnesium, the shaking time, the efficiency of Ba removal, and the sample matrix - to ensure quantitative recoveries. We employed repetitive laser ablation to remove the dried-droplet samples from the filter medium and introduce them into the ICP-MS system for determinations of REEs. The enrichment factors ranged from 8 to 88. The detection limit, at an enrichment factor of 32, ranged from 0.03 to 0.20 pg mL(-1). The relative standard deviations for the determination of REEs at a concentration of 1 ng mL(-1) when processing 40 mL sample solution were 2.0-4.8%. We applied this method to the satisfactory determination of REEs in lake water and synthetic seawater samples.


Assuntos
Precipitação Química , Lasers , Hidróxido de Magnésio/química , Espectrometria de Massas/métodos , Metais Terras Raras/análise , Metais Terras Raras/química , Água/química , Bário/química , Estudos de Viabilidade , Concentração de Íons de Hidrogênio , Reprodutibilidade dos Testes , Rios/química , Água do Mar/química , Fatores de Tempo
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