Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Más filtros












Base de datos
Intervalo de año de publicación
1.
Inorg Chem ; 61(48): 19156-19171, 2022 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-36414004

RESUMEN

Fast selective catalytic reduction of nitrogen oxide with ammonia (NH3-SCR) (2NH3 + NO2 + NO → 2N2 + 3H2O) has aroused great interest in recent years because it is inherently faster than the standard NH3-SCR reaction (4NO + 4NH3 + O2 → 4N2 + 6H2O). In the present paper, the mechanism of the fast NH3-SCR reaction catalyzed by a series of single-atom catalysts (SACs), M1/PTA SACs (PTA = Keggin-type phosphotungstic acid, M = Mn, Fe, Co, Ni, Ru, Rh, Pd, Ir, and Pt), has been systematically studied by means of density functional theory (DFT) calculations. Molecular geometry and electronic structural analysis show that Jahn-Teller distortion effects promote an electron transfer process from N-H bonding orbitals of the NH3 molecule to the symmetry-allowed d orbitals (dxy and dx2-y2) of the single metal atom, which effectively weakens the N-H bond of the adsorbed NH3 molecule. The calculated free energy profiles along the favorable catalytic path show that decomposition of NH3 to *NH2 and *H species and decomposition of *NHNOH into N2 and H2O have high free energy barriers in the whole fast NH3-SCR path. A good synergistic effect between the Brønsted acid site (surface oxygen atom in the PTA support) and the Lewis acid site (single metal atom) effectively enhances the decomposition of NH3 to *NH2 and *H species. M1/PTA SACs (M = Ru, Rh, Pd, and Pt) were found to have potential for fast NH3-SCR reaction because of the relatively small free energy barrier and strong thermodynamic driving forces. We hope our computational results could provide some new ideas for designing and fabricating fast NH3-SCR catalysts with high activity.

2.
RSC Adv ; 12(29): 18773-18778, 2022 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-35873316

RESUMEN

Aniline is one of the important organic chemical raw materials and is widely used in the chemical production industry, including dyes, pharmaceuticals, pesticides, explosives, spices, etc. At present, the yield and selectivity of aniline synthesis by direct amination are relatively low, and how to improve the catalytic efficiency has become an urgent problem to be solved. A series of Ti-V-MCM-41 catalysts with different silicon-titanium ratios was prepared by the hydrothermal synthesis method. According to the analysis of XRD, FT-IR, UV-vis DRS, BET, and SEM characterization of Ti-V-MCM-41, it was found that V-O-Si and Ti-O-Si were distributed on Ti-V-MCM-41. The direct photocatalysis amination of benzene and ammonia to aniline can be realized under mild conditions with this catalyst. The yield and selectivity of aniline were improved to 6.11% and 90.7%, respectively, by optimizing the synthesis and reaction conditions.

3.
Mol Ther Nucleic Acids ; 23: 757-768, 2021 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-33614227

RESUMEN

Ovarian cancer (OvCa) is the most lethal gynecologic malignancy owing to its high chemoresistance and late diagnosis, which lead to a poor prognosis. Hence, developing new therapeutic modalities is important for OvCa patient treatment. Our previous results indicated that a novel aptamer, Tx-01, can specifically recognize serous carcinoma cells and tissues. Here, we aim to clarify the clinical role and possible molecular mechanisms of Tx-01 in OvCa. Immunostaining and statistical analysis were performed to detect the interaction of Tx-01 and heat shock protein 70/Notch1 intracellular domain (HSP70/NICD) in OvCa. The in vitro and in vivo experiments were carried out to demonstrate the potential mechanisms of Tx-01. Results show that Tx-01 reduced serous OvCa OVCAR3 cell migration and invasion and inhibited HSP70 nuclear translocation by interrupting the intracellular HSP70/NICD interaction. Furthermore, Tx-01 suppressed serous-type OVCAR3 cell tumor growth in vivo. Tx-01 acts as a prognostic factor through its interaction with membrane-bound HSP70 (mHSP70 that locates on the cell surface without direct interaction to NICD) on ascitic circulating tumor cells (CTCs) and is reported to be involved in natural killer (NK) cell recognition and activation. Our data demonstrated that Tx-01 interacted with HSP70 and showed therapeutic and prognostic effects in serous OvCa. Tx-01 might be a potential inhibitor for use in serous OvCa treatment.

4.
Appl Microbiol Biotechnol ; 94(6): 1505-19, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22350319

RESUMEN

Antrodia camphorata is a particular and precious medicinal mushroom, and its fruiting body was found to provide more efficient protection from oxidative stress and inflammation than its mycelium because of its higher content of triterpenoids, total phenols, and so on. In the previous in vitro studies, the mycelium of A. camphorata is proven to provide strong neuroprotection in neuron cells and suggested to have the potential of protection against neurotoxicity of amyloid ß-protein (Aß) known as the risk factor toward Alzheimer's disease (AD) development. However, the in vivo study and the comparison study with the fruiting body have not yet been investigated. This study compared the effect of the fruiting body and mycelium of A. camphorata on alleviating the Aß40-induced neurocytotoxicity in the in vitro Aß-damaged neuron cell model (PC-12 cell treated with Aß40) and memory impairment in the in vivo AD animal model induced with a continuous brain infusion of Aß40. In the results of in vitro and in vivo studies, the fruiting body possessed stronger anti-oxidative and anti-inflammatory abilities for inhibiting neurocytotoxicity in Aß40-treated PC-12 cells and Aß40 accumulation in Aß40-infused brain than mycelium. Moreover, hyperphosphorylated tau (p-tau) protein expression, known as an important AD risk factor, was suppressed by the treatment of fruiting body rather than that of mycelium in the in vitro and in vivo studies. These comparisons supported the reasons why the fruiting body resulted in a more significant improvement effect on working memory ability than mycelium in the AD rats.


Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/psicología , Péptidos beta-Amiloides/toxicidad , Antrodia/química , Cuerpos Fructíferos de los Hongos/química , Memoria/efectos de los fármacos , Micelio/química , Fármacos Neuroprotectores/metabolismo , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Animales , Antrodia/crecimiento & desarrollo , Línea Celular , Cuerpos Fructíferos de los Hongos/crecimiento & desarrollo , Humanos , Masculino , Micelio/crecimiento & desarrollo , Fármacos Neuroprotectores/farmacología , Ratas , Ratas Wistar
5.
J Asthma ; 45(7): 539-44, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18773322

RESUMEN

As frequently there is no school nurse in a kindergarten setting, teachers receiving non-medical training take the primary roles of symptom assessment and management of young children with asthma. This article presents the knowledge, attitudes, and self-efficacy of asthma in kindergarten teachers in Taiwan. A total valid sample of 460 teachers was recruited from 70 kindergartens. Results showed most teachers understood the basic facts about asthma rather than the complex issues; they demonstrated positive attitudes toward having asthmatic children in class. Regarding self-efficacy, teachers lacked confidence in their ability to manage asthma attacks. Teachers' asthma knowledge showed a significant positive correlation with attitude (r = 0.27, p < 0.001) and self-efficacy knowledge (r = 0.23, p < 0.001). Given the need to help kindergarten teachers take care of children with asthma, the implications of kindergarten teachers' in-service education and training to asthma care are also discussed.


Asunto(s)
Asma , Conocimientos, Actitudes y Práctica en Salud , Enseñanza , Adulto , Femenino , Educación en Salud , Humanos , Masculino , Percepción , Autoeficacia , Taiwán
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...