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1.
Behav Brain Sci ; 43: e64, 2020 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-32349811

RESUMO

In place of Tomasello's explanation for the source of moral obligation, we suggest that it develops from the concern for others already implicit in the human developmental system. Mutual affection and caring make the development of communication and thinking possible. Humans develop as persons within such relationships and this develops into respect and moral obligation.


Assuntos
Obrigações Morais , Estanho , Humanos , Princípios Morais
2.
Sci Total Environ ; 732: 138963, 2020 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-32428768

RESUMO

In this paper, a new interface design strategy for bio­carbon/SnS2 nanosheets equipped with CSnS bonds was proposed by using biomass as a template for the efficient photocatalytic conversion of As(III). The characterization results illustrated that the CSnS bonds could effectively prevent the agglomeration of SnS2, expand the photoresponse range and improve the hydrophilicity of the bio­carbon/SnS2 composites while reducing their transfer resistance. Therefore, the construction of CSnS bonds could more efficiently promote the photoredox catalysis of As(III) to As(V) compared with pure SnS2, attributing to the polarization and conjugation effects of the CSn bonds. Meanwhile, CaSO4·nH2O (n = 0, 0.5, 2) could rapidly convert AsO43- into Ca3(AsO4)2 precipitates to eliminate arsenic from the aqueous solution in one step. In particular, 7500 µg/L As(III) could not only be photocatalyzed into As(V) but also be converted to Ca3(AsO4)2 to achieve the removal of arsenic within only 55 min in the coexistence of CaSO4. In addition, the electron transfer path in the photocatalytic oxidation system on arsenite was proposed according to the Mott-Schottky (MS) plots of SnS2 and graphitic carbon. The electron paramagnetic resonance (EPR) results implied that O2- and h+ were the main active substances in the photooxidation arsenic system and the effect of OH could be negligible. Thus, the possible mechanism of the photocatalytic conversion of As(III) was discussed.


Assuntos
Biomassa , Arseniatos , Compostos de Cálcio , Carbono , Catálise , Oxirredução , Processos Fotoquímicos , Enxofre , Estanho
3.
Sci Total Environ ; 719: 137458, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32112946

RESUMO

BACKGROUND: Adipose tissue has been acknowledged as a potential target for obesogenic pollutants, including toxic metal(loid)s. However, the presence of these chemicals in the adipose tissue has been poorly characterized. OBJECTIVE: To examine the distributions of adipose tissue concentrations of five toxic metal(loid)s (i.e., arsenic [As], nickel [Ni], lead [Pb], tin [Sn], and titanium [Ti]) in adults, and potential socio-demographic and lifestyle factors associated with metal(loid) concentrations. METHODS: The study population consisted of a subsample of 228 subjects from GraMo cohort in Southern Spain (N = 387). Adipose tissue samples were intra-operatively collected from adults recruited in 2003-2004 in two public hospitals, and concentrations of metal(loid)s in adipose tissue were analyzed in 2015 by High-Resolution Inductively Coupled Plasma Mass Spectrometry. Data on socio-demographic and lifestyle factors were obtained by baseline questionnaire completion. Linear and multinomial regression was used to identify factors associated with metal(loid) levels. RESULTS: Ni, Pb, Sn, and Ti were detected in all adipose tissue samples, and As in 51% of them. Ni was the metal showing the highest median concentration (0.56 µg/g), followed by Ti (0.31 µg/g), Pb (0.08 µg/g), Sn (0.06 µg/g), and As (0.003 µg/g). Predictors of As levels included area of residence, social class, and oily fish intake; for Ni: area of residence and consumption of cheese, meat, eggs, and canned food; for Pb: vegetables intake and industrial occupation; for Sn: age, body mass index, and consumption of lean fish, eggs, and milk; and cheese intake for Ti. Some of these predictors were sex-specific, particularly those regarding dietary intake. CONCLUSIONS: This exploratory study provides the first evidence of the occurrence of Ni, Pb, Sn, Ti, and As in adipose tissue from adult population, and highlights the potential of this tissue as a biological matrix for studying exposure levels and chronic health effects of toxic metal(loid)s.


Assuntos
Tecido Adiposo , Envelhecimento , Animais , Arsênico , Feminino , Chumbo , Masculino , Níquel , Espanha , Estanho , Titânio
4.
PLoS One ; 15(2): e0228376, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32023294

RESUMO

OBJECTIVES: The purpose of this study was to investigate the impact of a 150kV spectral filtration chest imaging protocol (Sn150kVp) combined with advanced modeled iterative reconstruction (ADMIRE) on radiation dose and image quality in patients after lung-transplantation. METHODS: This study included 102 patients who had unenhanced chest-CT examinations available on both, a second-generation dual-source CT (DSCT) using standard protocol (100kVp, filtered-back-projection) and, on a third-generation DSCT using Sn150kVp protocol with ADMIRE. Signal-to-noise-ratio (SNR) was measured in 6 standardized regions. A 5-point Likert scale was used to evaluate subjective image quality. Radiation metrics were compared. RESULTS: The mean time interval between the two acquisitions was 1.1±0.7 years. Mean-volume-CT-dose-index, dose-length-product and effective dose were significantly lower for Sn150kVp protocol (2.1±0.5mGy;72.6±16.9mGy*cm;1.3±0.3mSv) compared to 100kVp protocol (6.2±1.8mGy;203.6±55.6mGy*cm;3.7±1.0mSv) (p<0.001), equaling a 65% dose reduction. All studies were considered of diagnostic quality. SNR measured in lung tissue, air inside trachea, vertebral body and air outside the body was significantly higher in 100kVp protocol compared to Sn150kVp protocol (12.5±2.7vs.9.6±1.5;17.4±3.6vs.11.8±1.8;0.7±0.3vs.0.4±0.2;25.2±6.9vs.14.9±3.3;p<0.001). SNR measured in muscle tissue was significantly higher in Sn150kVp protocol (3.2±0.9vs.2.6±1.0;p<0.001). For SNR measured in descending aorta there was a trend towards higher values for Sn150kVp protocol (2.8±0.6 vs. 2.7±0.9;p = 0.3). Overall SNR was significantly higher in 100kVp protocol (5.0±4.0vs.4.0±4.0;p<0.001). On subjective analysis both protocols achieved a median Likert rating of 1 (25th-75th-percentile:1-1;p = 0.122). Interobserver agreement was good (intraclass correlation coefficient = 0.73). CONCLUSIONS: Combined use of 150kVp tin-filtered chest CT protocol with ADMIRE allows for significant dose reduction while maintaining highly diagnostic image quality in the follow up after lung transplantation when compared to a standard chest CT protocol using filtered back projection.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Pneumopatias/diagnóstico por imagem , Transplante de Pulmão/métodos , Intensificação de Imagem Radiográfica/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Radiografia Torácica/métodos , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Feminino , Humanos , Pneumopatias/cirurgia , Masculino , Pessoa de Meia-Idade , Doses de Radiação , Intensificação de Imagem Radiográfica/métodos , Estudos Retrospectivos , Razão Sinal-Ruído , Estanho
5.
Molecules ; 25(2)2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31936773

RESUMO

Unique eleven-membered rings containing silicon, germanium, and tin were synthesized in good yields by the reactions of the corresponding 1,2-bis((2-bromothiophen-3-yl)methoxy)benzenes with (C6H5)2ECl2 where E = Sn, Ge, Si. The Sn and Ge congeners were crystallized, but the conformers that these rings crystallized in, were quite different. As confirmed by Density Functional Theory (DFT) calculations, (C28H22O2S2Sn) assumes a unique crystal structure that leaves more room around the tetrel atom as compared to the crystal structure of the corresponding Ge compound. In the latter, the central cavity is quite open, whereas in the former, one of the methylene groups can fold inwards. Another consequence is the influence on the planes of the aromatic rings flanking the heterocycle. In the Ge case, the benzene ring is folded away from the central cavity, whereas in the Sn case, it is almost parallel to the imaginary axis through the center of the ring. Thermal analysis investigations (TGA and DSC methods) of these eleven-membered rings suggested the loss of a phenyl group in the first decomposition step. The decomposition temperature decreased from the Si containing heterocycle to Ge and was lowest for the Sn containing heterocycle.


Assuntos
Germânio/química , Compostos Heterocíclicos/química , Compostos Heterocíclicos/síntese química , Modelos Moleculares , Silício/química , Estanho/química , Cristalografia por Raios X
6.
Chemosphere ; 243: 125284, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31759210

RESUMO

In order to recognize organic contaminants responsible for ecological stresses from intensive shipping traffic and dockyard works, this study aimed at characterizing the sediment contamination of a large industrialized port located in Hainan Island, China. Surface sediment samples were collected from 17 stations including the main docks, the dockyards and the major industrial wastewater outlets. Organotin compounds, the pesticide DDT (bis(chlorophenyl)trichloroethane) and its metabolites and polycyclic aromatic compounds were identified as main pollutant groups by GC/MS applying a non-target screening approach. The pesticide DDT and its metabolites were found in the same samples as the organotin derivatives pointing to similar emission sources. The concurrent presence of these compounds in the dockyard samples suggests a combined usage of organotin compounds and DDT as active ingredients in antifouling paints in Yangpu. As highly specific molecular indicators for dockyard activities, butyltin and phenyltin compounds were identified. Noteworthy, also tributylmethyltin and triphenylmethyltin were detected, likely resulting from microbial assisted biomethylation of synthetic organotin compounds in the sediments. The concentrations of PAHs, DDX and TBT in sediments from dockyards exceeded global sediment quality guidelines and the toxicity thresholds, and potentially have adverse biological effects on marine organisms.


Assuntos
Diclorodifenil Dicloroetileno/análise , Monitoramento Ambiental , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes Químicos da Água/análise , China , Sedimentos Geológicos , Desenvolvimento Industrial , Compostos Orgânicos de Estanho/análise , Navios , Estanho/análise
7.
J Trace Elem Med Biol ; 57: 18-20, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31546208

RESUMO

Huntington' disease (HD) is an autosomal dominant neurodegenerative disease characterized by progressive motor, psychiatric, and cognitive deterioration. HD is, together with spinocerebellar ataxias, spinobulbar muscular atrophy and dentatorubral-pallido- luysian atrophy, one of the nine disorders caused by an expansion of glutamine residues in the causative protein where the polyglutamine expansion cause aberrant protein folding. Since an excessive metal's accumulation in organs may induce protein misfolding and oxidative stress, we have studied the blood concentration of essential (Cr, Co, Cu, Fe, Mn, Mo, Ni, Se, Zn) and nonessential (As, Cd, Sb, Sn, V) trace elements in HD patients. We found increased levels of the essential elements iron, chromium, selenium and zinc and of the nonessential element arsenic in the blood of HD patients. Since alteration in metals homeostasis may contribute to the pathogenesis of neurodegenerative disease and could eventually constitute a target for therapy, we may suggest the utilize of the blood metal profile as a further in vivo tool to study and characterize Huntington disease.


Assuntos
Doença de Huntington/sangue , Oligoelementos/sangue , Cádmio/sangue , Cobalto/sangue , Feminino , Humanos , Masculino , Molibdênio/sangue , Níquel/sangue , Estanho/sangue
8.
Chemosphere ; 245: 125601, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31862553

RESUMO

Low levels of antimony (Sb) can be effectively removed from water by adsorption onto various materials, and searching for low-cost and high-efficiency new adsorbents has been a hot topic in recent years. In the present study, the performance of cetyltrimethylammonium bromide (CTAB) modified MnFe2O4/MnO2 composites (CTAB/MnFe2O4/MnO2) as an adsorbent for Sb(III) removal from aqueous solution was investigated. Kinetic study revealed that adsorption of Sb(III) by CTAB/MnFe2O4/MnO2 was fast in the first 430 min and the equilibrium was achieved within 1440 min. The adsorption kinetic data were well fitted with pseudo-second-order model. The maximum adsorption capacity of the synthesized adsorbent for Sb(III) at pH 7 calculated from Langmuir adsorption isotherms in batch experiments was 321.03 mg g-1. During the adsorption process, Sb(III) can be simultaneously oxidized to Sb(V) and the average oxidation percentage reached 95.43% within 1440 min. The adsorption capacity did not significantly vary with pH. Common metal cations (Ca2+ and Mg2+) slightly enhanced Sb(III) adsorption at pH 7. In comparison, the effect of anions (Cl-, NO3-, and PO43-) on Sb(III) adsorption was not obvious. The results suggest that CTAB/MnFe2O4/MnO2 is a potential cost-effective adsorbent for Sb(III) removal in water treatment.


Assuntos
Antimônio/isolamento & purificação , Cetrimônio/química , Estanho/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Antimônio/química , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Cinética , Compostos de Manganês/química , Oxirredução , Óxidos/química , Poluentes Químicos da Água/química
9.
Biosens Bioelectron ; 147: 111790, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31669805

RESUMO

In this study, modified hollow titanium dioxide and SnS2 quantum dots (SnS2 QDs) were used to build a novel electrochemiluminescence immunoassay (ECLIA) for ultrasensitive detection of chloramphenicol (CAP). The titanium dioxide hollow spheres (THS) modified with polyethyleneimine (PEI) and gold nanoparticles (Au NPs) was synthesized as a probe material for the novel ECLIA, meanwhile it also could be a coreaction accelerator which could greatly improve the interaction efficiency between SnS2 QDs and S2O82-. Then the modified THS was combined with chloramphenicol antibody to form ECLIA probes, and colloidal gold synthesized as a platform for an ECLIA by ascorbic acid (AA) reduction. A competitive immunoassay strategy was used for the detection of CAP, where CAP in the sample would compete with the coating antigen for the limited antibodies. The proposed ECLIA for CAP detection exhibited high sensitivity with a wide linear range from 0.01 ng mL-1 to 100 ng mL-1 and a low detection limit at 3.1 pg mL-1. Furthermore, it could be seen from electrochemical analysis that the effect of THS on the enhancement of ECL signal is about twice as high as that of ordinary titanium dioxide. Importantly, this work not only successfully applied THS to amplify electrochemical-luminescence signal in the ECLIA, but also successfully prepared a stable and highly selective sensor for ultrasensitive detection of CAP.


Assuntos
Técnicas Biossensoriais , Cloranfenicol/isolamento & purificação , Técnicas Eletroquímicas , Nanopartículas Metálicas/química , Cloranfenicol/química , Dissulfetos/química , Medições Luminescentes , Pontos Quânticos/química , Estanho/química , Titânio/química
10.
Mikrochim Acta ; 186(12): 755, 2019 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-31707595

RESUMO

Platinum nanoparticles were loaded on CoSn(OH)6 nanocubes via a co-precipitation method. The material (NCs) is shown to be a viable peroxidase mimic that catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) to generate oxidized TMB (oxTMB) with absorption at 652 nm. The formation of the blue color can be observed in <30 s. Thus, a visual and colorimetric assay was worked out for H2O2. It has a detection limit as low as 4.4 µM and works in the 5 to 200 µM concentration range. The method was also used to detect dopamine (DA) which is found to inhibit the enzyme mimicking activity of the NCs. Hence, less blue color is formed in its presence. The respective DA assay has a linear response in the 5.0 to 60 µM concentration range and a 0.76 µM detection limit. Graphical abstractSchematic diagram of a visual colorimetric method for determination of H2O2 and dopamine (DA) with the aid of color change of 3,3',5,5'-tetramethylbenzidine (oxTMB), based on the peroxidase-like activity of Pt/CoSn(OH)6 nanocubes.


Assuntos
Colorimetria/métodos , Dopamina/sangue , Nanopartículas Metálicas/química , Benzidinas/química , Catálise , Cobalto/química , Corantes/química , Humanos , Peróxido de Hidrogênio/química , Hidróxidos/química , Limite de Detecção , Oxirredução , Peroxidase/química , Platina/química , Estanho/química
11.
Chem Commun (Camb) ; 55(87): 13148-13151, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31617549

RESUMO

Cu2ZnSnS4 nanocrystals (CZTS NCs) have been demonstrated to be effective in tumor therapy as a novel susceptible agent for microwave thermal and microwave dynamic therapy. CZTS NCs intensify the heating effect of microwaves with a significant temperature increase of about 15 °C compared to the control group and showed remarkable anti-tumor performance after 5 min of microwave irradiation. For the first time, we report the microwave absorption performance and singlet oxygen production of CZTS NCs used in microwave therapy, which reveals new opportunities for novel combined mechanisms of microwave thermal and microwave dynamic tumor therapies.


Assuntos
Antineoplásicos/uso terapêutico , Cobre/uso terapêutico , Neoplasias Hepáticas/tratamento farmacológico , Micro-Ondas , Nanopartículas/uso terapêutico , Sulfetos/uso terapêutico , Temperatura , Estanho/uso terapêutico , Zinco/uso terapêutico , Animais , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Terapia Combinada , Cobre/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Neoplasias Hepáticas Experimentais/patologia , Camundongos , Nanopartículas/química , Tamanho da Partícula , Relação Estrutura-Atividade , Sulfetos/química , Propriedades de Superfície , Estanho/química , Zinco/química
12.
Molecules ; 24(19)2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31547625

RESUMO

Cu2ZnSnS4 (CZTS) ink was synthesized from metal chloride precursors, sulfur, and oleylamine (OLA), as a ligand by a simple and low-cost hot-injection method. Thin films of CZTS were then prepared by spin coating, followed by thermal annealing. The effects of the fabrication parameters, such as ink concentration, spinning rate, and thermal treatment temperatures on the morphology and structural, optical, and electrical properties of the films were investigated. As expected, very thin films, for which the level of transmittance and band-gap values increase, can be obtained either by reducing the concentration of the inks or by increasing the rate of spinning. Moreover, the thermal treatment affects the phase formation and crystallinity of the film, as well as the electrical conductivity, which decreases at a higher temperature.


Assuntos
Cobre/química , Sulfetos/química , Estanho/química , Zinco/química , Aminas/química , Antineoplásicos/química , Cristalização , Tamanho da Partícula , Soluções , Propriedades de Superfície , Temperatura
13.
Mater Sci Eng C Mater Biol Appl ; 105: 110064, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546403

RESUMO

The aim of this study was to investigate the effect of adding 1, 2 and 4% wt of cerium on the microstructure, mechanical and corrosion properties of high pressure die casting (HPDC) Mg-4Sn alloys. Microstructure analyses of the alloys were carried out using X-Ray Diffraction (XRD) and Scanning Electron microscopy (SEM). The corrosion behaviors were determined with the potentiodynamic polarization and immersion tests in Hanks Balanced Salt Solution (HBSS), which is used as the artificial body fluid. The microstructural results showed that the addition of Ce to the main alloy creates new intermetallic phases (Ce5Sn4 and MgSnCe). In addition, Ce addition provided effectively the grain refinement of the alloys. While the hardness and yield strength of the Mg-4Sn alloy enhanced continuously with increasing Ce content, the tensile strength and elongation reached up to 2% wt. The corrosion resistance of the main alloy was improved by the addition of 1% wt of Ce. However, the Ce content, which is more than 1% wt decreased corrosion resistance.


Assuntos
Ligas/química , Cério/química , Magnésio/química , Estanho/química , Microscopia Eletroquímica de Varredura , Propriedades de Superfície
14.
Mater Sci Eng C Mater Biol Appl ; 104: 109949, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499955

RESUMO

The paper presents a comparative study of the impact that TiN, ZrN and DLC nanocoatings on titanium implants have on animal organisms. The experiment lasted 602 days and used 15 laboratory animals (rabbits from the Lagomorph species). Implants, eight of each type, were implanted subcutaneously in the cervical region. The control group consisted of three animals. Over the course of the experiment, at the beginning and subsequently every 7 days, the animals had their blood drawn and analysed for parameters indicating inflammation. Once the experiment ended, a histopathological evaluation of the animals' internal organs was conducted, and the places where the implants came into contact with the tissue were also assessed. The results of the laboratory tests did not indicate any characteristics of inflammation for any of the coatings. The histopathological examination confirmed biocompatibility in all cases. This is of great importance in the case of the DLC coating, which, due to its tribological properties - a low friction coefficient - has a very high potential for application in various areas of medicine.


Assuntos
Carbono/química , Materiais Revestidos Biocompatíveis/química , Diamante/química , Estanho/química , Titânio/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Inflamação/tratamento farmacológico , Masculino , Teste de Materiais/métodos , Próteses e Implantes , Coelhos , Propriedades de Superfície
15.
Chemistry ; 25(61): 14003-14009, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31469199

RESUMO

The systematic assembly of supramolecular arrangements is a persistent challenge in modern coordination chemistry, especially where further aspects of complexity are concerned, as in the case of large molecular mixed-metal arrangements. One targeted approach to such heterometallic complexes is to engineer metal-based donor ligands of the correct geometry to build 3D arrangements upon coordination to other metals. This simple idea has, however, only rarely been applied to main group metal-based ligand systems. Here, we show that the new, bench-stable tris(3-pyridyl)stannane ligand PhSn(3-Py)3 (3-Py=3-pyridyl) provides simple access to a range of heterometallic SnIV /transition metal complexes, and that the presence of weakly coordinating counter anions can be used to build discrete molecular arrangements involving anion encapsulation. This work therefore provides a building strategy in this area, which parallels that of supramolecular transition metal chemistry.


Assuntos
Complexos de Coordenação/química , Metais/química , Polímeros/química , Compostos de Estanho/química , Cristalografia por Raios X , Ligantes , Conformação Molecular , Estanho/química
16.
Mar Pollut Bull ; 146: 263-273, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426156

RESUMO

Metals are subject to internal subcellular compartmentalization, altering their bioavailability. Thus, subcellular metal assessments are crucial in biomonitoring efforts. Metal distribution in three subcellular fractions (insoluble - ISF, thermolabile - TLF and thermostable - TSF) were determined by ICP-MS in Steno bredanensis specimens from Southeastern Brazil. Associations between metals, metallothionein (MT) and reduced glutathione (GSH) were also investigated. Differential metal-detoxification mechanisms were observed. MT detoxification was mostly noted for As, Cd, and Pb, while Cu, Cr, Hg, Ni, Se and Ti displayed lower MT-associations. Fe, Zn and Se, on the other hand, were poorly associated to MT, and mostly present in the ISF, indicating low bioavailability. This is the first report on subcellular Sn and Ti distribution in cetaceans and the first in this species in Brazil. Potential protective roles of essential metals against toxic elements are postulated. This study indicates that important biochemical detoxification information is obtained through subcellular fraction analyses in marine mammals.


Assuntos
Golfinhos/metabolismo , Monitoramento Ambiental/métodos , Metalotioneína/metabolismo , Metais/metabolismo , Frações Subcelulares/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Brasil , Glutationa/metabolismo , Inativação Metabólica , Metais Pesados/análise , Estanho/metabolismo , Titânio/metabolismo
17.
J Mater Sci Mater Med ; 30(8): 91, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31388766

RESUMO

Customized porous titanium alloys have become the emerging materials for orthopaedic implant applications. In this work, diamond and rhombic dodecahedron porous Ti-33Nb-4Sn scaffolds were fabricated by selective laser melting (SLM). The phase, microstructure and defects characteristics were investigated systematically and correlated to the effects of pore structure, unit cell size and processing parameter on the mechanical properties of the scaffolds. Fine ß phase dendrites were obtained in Ti-33Nb-4Sn scaffolds due to the fast solidification velocity in SLM process. The compressive and bending strength of the scaffolds decrease with the decrease of strut size and diamond structures showed both higher compressive and bending strength than the dodecahedron structures. Diamond Ti-33Nb-4Sn scaffold with compressive strength of 76 MPa, bending strength of 127 MPa and elastic modulus of 2.3 GPa was achieved by SLM, revealing the potential of Ti-33Nb-4Sn scaffolds for applications on orthopaedic implant.


Assuntos
Nióbio/química , Equipamentos Ortopédicos , Próteses e Implantes , Estanho/química , Tecidos Suporte/química , Titânio/química , Ligas/síntese química , Ligas/química , Materiais Biocompatíveis , Fenômenos Biomecânicos , Força Compressiva , Módulo de Elasticidade , Manufaturas/análise , Teste de Materiais , Ortopedia , Porosidade , Próteses e Implantes/ultraestrutura , Estresse Mecânico , Propriedades de Superfície
18.
Environ Toxicol Chem ; 38(12): 2651-2658, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31441966

RESUMO

Recently, monoalkyl oxo-hydroxo tin clusters have emerged as a new class of metal-oxide resist to support the semiconductor industry's transition to extreme ultraviolet (EUV) lithography. Under EUV exposure, these tin-based clusters exhibit higher performance and wider process windows than conventional polymer materials. A promising new monoalkyl precursor, [(BuSn)12 O14 (OH)6 ][OH]2 (BuSn), is still in its infancy in terms of film formation. However, understanding potential environmental effects could significantly affect future development as a commercial product. We synthesized and explored the toxicity of nano-BuSn in the alga Chlamydomonas reinhardtii and the crustacean Daphnia magna at exposure concentrations ranging from 0 to 250 mg/L. Nano-BuSn had no effect on C. reinhardtii growth rate irrespective of concentration, whereas high nanoparticle concentrations (≥100 mg/L) increased D. magna immobilization and mortality significantly. To simulate an end-of-life disposal and leachate contamination, BuSn-coated film wafers were incubated in water at various pH values and temperatures for 14 and 90 d to investigate leaching rates and subsequent toxicity of the leachates. Although small quantities of tin (1.1-3.4% of deposited mass) leached from the wafers, it was insufficient to elicit a toxic response regardless of pH, incubation time, or temperature. The low toxicity of the tin-based thin films suggests that they can be an environmentally friendly addition to the material sets useful for semiconductor manufacturing. Environ Toxicol Chem 2019;38:2651-2658. © 2019 SETAC.


Assuntos
Chlamydomonas/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Estanho/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Chlamydomonas/crescimento & desenvolvimento , Daphnia/crescimento & desenvolvimento , Óxidos/análise , Óxidos/toxicidade , Estanho/análise , Poluentes Químicos da Água/análise
19.
Waste Manag ; 96: 181-189, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31376963

RESUMO

In this work, an environmentally-friendly leaching process for the recovery of indium (In) and tin (Sn) from LCD panel waste was investigated. Easily degradable citrates (C6H5O73-), i.e., sodium citrate and citric acid, were used as complexing agents. The morphology and composition of the species present in the LCD powder before and after the leaching processes were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The concentrations of In, Sn, and iron (Fe) present in the leachate were determined by atomic absorption spectrometry (AAS). The necessary thermodynamic conditions for achieving substantial In recovery were established by using MEDUSA software. The optimal process conditions were determined experimentally by varying the initial citrate concentration as well as by using reducing or oxidizing media, respectively hydrazine (N2H4) or hydrogen peroxide (H2O2). It was found that using N2H4 in a citrate solution as a reducing agent enhances the leaching efficiency. However, high concentrations of Sn and Fe with respect to In were found in the LCD powder. Therefore, a pretreatment processes to first remove the excess of Sn and Fe, which compete with In for the citrate, was implemented. Leaching with 1 M citrate, 0.2 M N2H4, at pH = 5, using sodium hydroxide (NaOH) at solid:liquid (S:L) ratio of 20 g∙L-1, yielded a remarkably high In recovery of 98.9% after 16.6 h.


Assuntos
Resíduo Eletrônico , Cristais Líquidos , Citratos , Ácido Cítrico , Peróxido de Hidrogênio , Índio , Reciclagem , Estanho
20.
Biosens Bioelectron ; 142: 111525, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31369944

RESUMO

In this work, a metallic composite with strong electrocatalytic property was designed by uniformly decorating Pt and Sn nanoparticles on the surface of TiO2 nanorods (Pt-Sn@TiO2). A detection scheme was then developed based on a dual signal amplification strategy involving the Pt-Sn@TiO2 composite and exonuclease assisted target recycling. The Pt-Sn@TiO2 composite exhibited an enhanced oxygen reduction current owing to the synergistic effect between Pt and Sn, as well as high exposure of Pt (111) crystal face. Initially, a Pt-Sn@TiO2 modified glassy carbon electrode produced an amplified electrochemical signal for the reduction of dissolved oxygen in the analyte solution. Next, a DNA with a complementary sequence to a streptomycin aptamer (cDNA) was immobilised on the Pt-Sn@TiO2 modified electrode, followed by the streptomycin aptamer that hybridised with cDNA. The corresponding oxygen reduction current was diminished by 51% attributable to the hindrance from the biomolecules. After a mixture of streptomycin and RecJf exonuclease was introduced, both the streptomycin-aptamer complex and the cDNA were cleaved from the electrode, making the Pt-Sn and Pt (111) surface available for oxygen reduction. RecJf would also release streptomycin from the streptomycin-aptamer complex, allowing it to complex again with aptamers on the electrode. This has then promoted a cyclic amplification of the oxygen reduction current by 85%, which is quantitatively related to streptomycin. Under optimal conditions, the aptasensor exhibited a linear range of 0.05-1500 nM and a limit of detection of 0.02±0.0045 nM streptomycin. The sensor was then used in the real-life sample detection of streptomycin to demonstrate its potential applications to bioanalysis.


Assuntos
Antibacterianos/análise , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/instrumentação , Nanocompostos/química , Estreptomicina/análise , Titânio/química , Animais , Técnicas Eletroquímicas/instrumentação , Desenho de Equipamento , Análise de Alimentos/instrumentação , Limite de Detecção , Leite/química , Nanocompostos/ultraestrutura , Oxirredução , Oxigênio/química , Platina/química , Estanho/química
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