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1.
ChemSusChem ; 10(21): 4198-4206, 2017 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-28941070

RESUMO

A primary Li-air battery has been developed with a flowing Li-ion free ionic liquid as the recyclable electrolyte, boosting power capability by promoting superoxide diffusion and enhancing discharge capacity through separately stored discharge products. Experimental and computational tools are used to analyze the cathode properties, leading to a set of parameters that improve the discharge current density of the non-aqueous Li-air flow battery. The structure and configuration of the cathode gas diffusion layers (GDLs) are systematically modified by using different levels of hot pressing and the presence or absence of a microporous layer (MPL). These experiments reveal that the use of thinner but denser MPLs is key for performance optimization; indeed, this leads to an improvement in discharge current density. Also, computational results indicate that the extent of electrolyte immersion and porosity of the cathode can be optimized to achieve higher current density.

2.
Nat Commun ; 7: 13869, 2016 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-27958290

RESUMO

Electroreduction of carbon dioxide into higher-energy liquid fuels and chemicals is a promising but challenging renewable energy conversion technology. Among the electrocatalysts screened so far for carbon dioxide reduction, which includes metals, alloys, organometallics, layered materials and carbon nanostructures, only copper exhibits selectivity towards formation of hydrocarbons and multi-carbon oxygenates at fairly high efficiencies, whereas most others favour production of carbon monoxide or formate. Here we report that nanometre-size N-doped graphene quantum dots (NGQDs) catalyse the electrochemical reduction of carbon dioxide into multi-carbon hydrocarbons and oxygenates at high Faradaic efficiencies, high current densities and low overpotentials. The NGQDs show a high total Faradaic efficiency of carbon dioxide reduction of up to 90%, with selectivity for ethylene and ethanol conversions reaching 45%. The C2 and C3 product distribution and production rate for NGQD-catalysed carbon dioxide reduction is comparable to those obtained with copper nanoparticle-based electrocatalysts.

3.
ChemSusChem ; 9(15): 1972-9, 2016 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-27345560

RESUMO

We introduce a gross-margin model to evaluate the technoeconomic feasibility of producing different C1 -C2 chemicals such as carbon monoxide, formic acid, methanol, methane, ethanol, and ethylene through the electroreduction of CO2 . Key performance benchmarks including the maximum operating cell potential (Vmax ), minimum operating current density (jmin ), Faradaic efficiency (FE), and catalyst durability (tcatdur ) are derived. The Vmax values obtained for the different chemicals indicate that CO and HCOOH are the most economically viable products. Selectivity requirements suggest that the coproduction of an economically less feasible chemical (CH3 OH, CH4 , C2 H5 OH, C2 H4 ) with a more feasible chemical (CO, HCOOH) can be a strategy to offset the Vmax requirements for individual products. Other performance requirements such as jmin and tcatdur are also derived, and the feasibility of alternative process designs and operating conditions are evaluated.


Assuntos
Dióxido de Carbono/química , Eletroquímica/economia , Modelos Teóricos , Benchmarking , Monóxido de Carbono/química , Condutividade Elétrica , Etanol/química , Etilenos/química , Formiatos/química , Metano/química , Metanol/química , Oxirredução
4.
Arch Pharm Res ; 31(2): 250-8, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18365698

RESUMO

A novel polymeric salt of clopidogrel, clopidogrel resinate, was prepared as a anticoagulant drug. To prove the feasibility as a new active substance, clopidogrel resinate was evaluated for its efficacy and safety. In accelerated stability tests, the clopidogrel resinate tablet (Pregrel) showed less brown discoloration and fewer impurities than the clopidogrel bisulfate tablets under open and closed conditions. In toxicity tests, no deaths occurred after a single dose of up to 2000 mg/kg/day and 13-week repeated doses of up to 625 mg/kg/day in rats without abnormal symptoms compared to clopidogrel bisulfate. When clopidogrel resinate was treated onto Caco-2 cell monolayers, clopidogrel, but not the resin, permeated across the cells with a hight permeation coefficient (Papp) of 13.5 +/- 1.13 x 10(-6) cm/sec. Clopidogrel resinate and clopidogrel bisulfate showed similar pharmacokinetics following oral administration to beagle dogs. A single oral administration of clopidogrel resinate dose-dependently inhibited ADP-induced ex vivo aggregation up to 30 mg/kg in rats. In conclusion, clopidogrel resinate was proved to be an efficient and safe polymeric salt as a candidate for a new clopidogrel salt.


Assuntos
Inibidores da Agregação Plaquetária/química , Inibidores da Agregação Plaquetária/farmacologia , Ticlopidina/análogos & derivados , Animais , Tempo de Sangramento , Células CACO-2 , Fenômenos Químicos , Físico-Química , Clopidogrel , Cães , Estabilidade de Medicamentos , Trato Gastrointestinal/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Absorção Intestinal/efeitos dos fármacos , Masculino , Camundongos , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/toxicidade , Polímeros , Ratos , Ratos Sprague-Dawley , Ticlopidina/química , Ticlopidina/farmacologia , Ticlopidina/toxicidade
5.
Cancer Res Treat ; 39(3): 99-103, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19746224

RESUMO

PURPOSE: We investigated the efficacy and safety of a combination of oxaliplatin, 5-fluorouracil (5-FU), and folinic acid (FA) as first-line palliative chemotherapy for elderly patients with metastatic or recurrent gastric cancer. MATERIALS AND METHODS: The study patients were chemotherapy-naïve patients (> 65 years old) with histologically confirmed, metastatic or recurrent gastric cancer. Chemotherapy consisted of oxaliplatin 100 mg/m(2) and FA 100 mg/m(2) (2-hour infusion), and then 5-FU 2400 mg/m(2) (46-hour continuous infusion) every 2 weeks. RESULTS: A total of 37 patients were studied between April 2004 and October 2006. Of the 34 evaluable patients, none achieved a complete response (CR) and 14 achieved a partial response (PR), resulting in an overall response rate of 41.2%. The median time to progression (TTP) was 5.7 months (95% CI: 4.2~6.3 months) and the median overall survival (OS) was 9.8 months (95% CI: 4.4~12.0 months). The main hematologic toxicities were anemia and neutropenia, which were observed in 56.7% and 32.4% of the patients, respectively. Grade 3/4 neutropenia was observed in 8.1% of the patients. None of the patients experienced febrile neutropenia. Peripheral neuropathy occurred in 35.1% of the patients and all were grade 1/2. CONCLUSION: This oxaliplatin/5-FU/FA regimen showed good efficacy and an acceptable toxicity profile in elderly patients with metastatic or recurrent gastric cancer.

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