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1.
Molecules ; 24(6)2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30875921

RESUMO

A method for detecting the organophosphorus pesticides residue and aflatoxins in China herbal tea has been developed by UPLC-MS/MS coupled with vortex-assisted dispersive liquid-liquid microextraction (DLLME). The extraction conditions for vortex-assisted DLLME extraction were optimized using single-factor experiments and response surface design. The optimum conditions for the experiment were the pH 5.1, 347 µL of chloroform (extraction solvent) and 1614 µL of acetonitrile (dispersive solvent). Under the optimum conditions, the targets were good linearity in the range of 0.1 µg/L⁻25 µg/L and the correlation coefficient above 0.9998. The mean recoveries of all analytes were in the ranged from 70.06%⁻115.65% with RSDs below 8.54%. The detection limits were in the range of 0.001 µg/L⁻0.01µg/L. The proposed method is a fast and effective sample preparation with good enrichment and extraction efficiency, which can simultaneously detect pesticides and aflatoxins in China herbal tea.


Assuntos
Aflatoxinas/análise , Praguicidas/análise , Chás de Ervas/análise , Cromatografia Líquida de Alta Pressão , Limite de Detecção , Microextração em Fase Líquida , Solventes/química , Espectrometria de Massas em Tandem
2.
ACS Appl Mater Interfaces ; 10(40): 34272-34282, 2018 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-30222306

RESUMO

As a promising cathode material of sodium-ion battery, P2-type Na2/3Ni1/3Mn2/3O2 (NNMO) possesses a theoretically high capacity and working voltage to realize high energy storage density. However, it still suffers from poor cycling stability mainly incurred by the undesirable P2-O2 phase transition. Herein, the electrochemically active Fe3+ ions are introduced into the lattice of NNMO, forming Na2/3Ni1/3Mn2/3- xFe xO2 ( x = 0, 1/24, 1/12, 1/8, 1/6) to effectively stabilize the P2-type crystalline structure. In such Fe-substituted materials, both Ni2+/Ni4+ and Fe3+/Fe4+ couples take part in the redox reactions, and the P2-O2 phase transition is well restrained during cycling, as verified by ex situ X-ray diffraction. As a result, the optimized Na2/3Ni1/3Mn7/12Fe1/12O2 (1/12-NNMF) has a long-term cycling stability with the fading rate of 0.05% per cycle over 300 cycles at 5 C. Furthermore, the 1/12-NNMF delivers excellent rate capabilities (65 mA h g-1 at 25 C) and superior low-temperature performance (the capacity retention of 94% at -25 °C after 80 cycles) owing to the enhanced Na diffusion upon Fe doping, which is deduced by the studies of electrode kinetics. More significantly, the 1/12-NNMF also displays remarkable sodium-ion full-cell properties when merged with an LS-Sb@G anode, thus implying the possibility of their practical application.

3.
Chemistry ; 24(38): 9606-9611, 2018 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-29633384

RESUMO

MnO is a promising high-capacity anode material for lithium-ion batteries (LIBs), but pristine material suffers short cycle life and poor rate capability, thus hindering the practical application. In this work, a new type of porous MnO microballs stringed with N-doped porous carbon (3DHB-MnO@NC) with a well-connected hierarchical three-dimensional network structure was prepared by the facile self-template method. The 3DHB-MnO@NC electrode can effectively promote the ion/electron transfer and buffer the large volume change of electrode during the electrochemical reaction. As the anode for LIBs, the 3DHB-MnO@NC possesses outstanding cycling performance (1247.7 mA h g-1 after 90 cycles at 200 mA g-1 ) and good rate capabilities (949.6 mA h g-1 after 450 cycles at 1000 mA g-1 ). The facile self-template method of the prepared 3DHB-MnO@NC composite paves a new way for practical applications of MnO in high performance LIBs.

4.
Chemistry ; 24(8): 1962-1970, 2018 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-29178323

RESUMO

Polymetallic complexes with interesting multifunctions have attracted extensive investigation. Synthesized through the use of different cobalt salt anions and solvents, five complexes, namely [CoII4 CoIII3 (H2 L)3 Cl5 (MeOH)] (1), [CoII4 CoIII3 (H2 L)3 (CH3 COO)4 (HCOO)⋅H2 O]n (2), [CoII4 CoIII3 (H2 L)3 (HCOO)4 (NO3 )⋅2H2 O]n (3), [CoII4 CoIII3 (H2 L)3 (bda)(CH3 COO)4 ⋅2H2 O]n (4), and [CoII4 CoIII3 (H2 L)3 (ipa)(HCOO)3 (dmf)⋅H2 O]n (5) (H6 L=bis-tris propane; BDA=biphenyl-4,4'-dicarboxylic acid; IPA=isophthalic acid; DMF=N,N-dimethylformamide), based on the heptanuclear {CoII4 CoIII3 } cluster with structures from 0D to 3D metal-organic frameworks (MOFs) have been solvothermally synthesized. Compound 1 is the first 0D heptanuclear cluster based on H6 L. Compound 2 crystallizes in the chiral space group P21 21 21 and consists of a 1D chiral helical chain. Complex 3 exhibits a 3D network structure. Compound 4 possesses a 1D zigzag-like chain structure. Finally, compound 5 was obtained as a 3D microporous structure. Compounds 1, 3, and 4 display dominant ferrimagnetic interactions whereas compounds 2 and 5 exhibit antiferromagnetic interactions. Moreover, the Co3 O4 prepared by calcining compound 2 presents a reversible capacity of 1122.9 mA h g-1 at 0.2 A g-1 after 100 cycles and an excellent rate capability, which suggests that coordination compounds with a 1D chain structure are outstanding precursors for preparing anode materials for lithium ion batteries.

5.
ACS Appl Mater Interfaces ; 9(12): 10708-10716, 2017 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-28263060

RESUMO

Marcasite (m-FeS2) exhibits higher electronic conductivity than that of pyrite (p-FeS2) because of its lower semiconducting gap (0.4 vs 0.7 eV). Meanwhile, as demonstrates stronger Fe-S bonds and less S-S interactions, the m-FeS2 seems to be a better choice for electrode materials compared to p-FeS2. However, the m-FeS2 has been seldom studied due to its sophisticated synthetic methods until now. Herein, a hierarchical m-FeS2 and carbon nanofibers composite (m-FeS2/CNFs) with grape-cluster structure was designed and successfully prepared by a straightforward hydrothermal method. When evaluated as an electrode material for lithium ion batteries, the m-FeS2/CNFs exhibited superior lithium storage properties with a high reversible capacity of 1399.5 mAh g-1 after 100 cycles at 100 mA g-1 and good rate capability of 782.2 mAh g-1 up to 10 A g-1. The Li-storage mechanism for the lithiation/delithiation processes of m-FeS2/CNFs was systematically investigated by ex situ powder X-ray diffraction patterns and scanning electron microscopy. Interestingly, the hierarchical m-FeS2 microspheres assembled by small FeS2 nanoparticles in the m-FeS2/CNFs composite converted into a mimosa with leaves open shape during Li+ insertion process and vice versa. Accordingly, a "CNFs accelerated decrystallization-recrystallization" mechanism was proposed to explain such morphology variations and the decent electrochemical performance of m-FeS2/CNFs.

6.
Asian Pac J Cancer Prev ; 16(9): 3773-7, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25987036

RESUMO

BACKGROUND: This study aimed to establish a nomogram by combining clinicopathologic factors with overall survival of stage IA-IIB cervical cancer patients after complete resection with pelvic lymphadenectomy. MATERIALS AND METHODS: This nomogram was based on a retrospective study on 1,563 stage IA-IIB cervical cancer patients who underwent complete resection and lymphadenectomy from 2002 to 2008. The nomogram was constructed based on multivariate analysis using Cox proportional hazard regression. The accuracy and discriminative ability of the nomogram were measured by concordance index (C-index) and calibration curve. RESULTS: Multivariate analysis identified lymph node metastasis (LNM), lymph-vascular space invasion (LVSI), stromal invasion, parametrial invasion, tumor diameter and histology as independent prognostic factors associated with cervical cancer survival. These factors were selected for construction of the nomogram. The C-index of the nomogram was 0.71 (95% CI, 0.65 to 0.77), and calibration of the nomogram showed good agreement between the 5-year predicted survival and the actual observation. CONCLUSIONS: We developed a nomogram predicting 5-year overall survival of surgically treated stage IA-IIB cervical cancer patients. More comprehensive information that is provided by this nomogram could provide further insight into personalized therapy selection.


Assuntos
Carcinoma de Células Escamosas/secundário , Histerectomia/mortalidade , Excisão de Linfonodo/mortalidade , Nomogramas , Neoplasias do Colo do Útero/patologia , Adulto , Idoso , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/cirurgia , Feminino , Seguimentos , Humanos , Metástase Linfática , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida , Neoplasias do Colo do Útero/mortalidade , Neoplasias do Colo do Útero/cirurgia
7.
Asian Pac J Cancer Prev ; 13(10): 5299-302, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23244152

RESUMO

PURPOSE: To investigate the diet of patients with cervical cancer and precancerosis in the Wufeng area, a high- incidence region in China. METHODS: In the case group, 104 patients diagnosed with cervical cancer or cervical intraepithelial neoplasias (CINII/III) were recruited from the Wufeng area. Nine hundred thirty-six healthy women were selected from the same area as the matched controls. A questionnaire, which included questions about general lifestyle conditions, smoking and alcohol status, source of drinking water, green tea intake, and diet in the past year, was presented to all participants. RESULTS: Green tea intake (P=0.022, OR=0.551, 95% CI=0.330-0.919) and vegetable intake (P=0.035, OR=0.896, 95% CI=0.809-0.993) were identified as protective factors against cervical cancer or CINII/III. There was no indication of any associations of other lifestyle factors (smoking status, alcohol status, source of drinking water) or diet (intake of fruit, meat/egg/milk, soybean food, onion/garlic, staple food and pickled food) with cervical cancer. CONCLUSIONS: The results suggest that eating more fresh vegetables and drinking more green tea may help to reduce the risk of cervical cancer or CINII/III in people of the Wufeng area.


Assuntos
Consumo de Bebidas Alcoólicas/efeitos adversos , Neoplasia Intraepitelial Cervical/epidemiologia , Dieta , Fumar/efeitos adversos , Neoplasias do Colo do Útero/epidemiologia , Adulto , Estudos de Casos e Controles , Neoplasia Intraepitelial Cervical/etiologia , Neoplasia Intraepitelial Cervical/prevenção & controle , China/epidemiologia , Comportamento Alimentar , Feminino , Humanos , Incidência , Estilo de Vida , Pessoa de Meia-Idade , Prognóstico , Fatores de Risco , Inquéritos e Questionários , Neoplasias do Colo do Útero/etiologia , Neoplasias do Colo do Útero/prevenção & controle
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