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排序方式: 共有881条查询结果,搜索用时 31 毫秒
181.
Raúl Felipe 《Reports on Mathematical Physics》2003,52(2):167-176
A new integrable hierarchy, with equations defined by double brackets of two matrix pseudo-differential operators (Lax pairs), is constructed. Some algebraic properties are demonstrated. It is also shown that each equation is equivalent to a certain gradient flow. A new version of the Zakharov-Shabat type equations is proved. Formal solutions of this hierarchy are constructed using a matrix “double bracket bilinear identity”. 相似文献
182.
Alessandra Pazini Luis Maqueira Harold C. Avila Felipe M. Valente Rian E. Aderne Davi Back Ricardo Q. Aucélio Marco Cremona Jones Limberger 《Tetrahedron letters》2018,59(31):2994-2999
The synthesis of a phenoxy-benzothiadiazole (BTD) derivative is reported for the first time. This derivative was employed as an intermediate in the obtention of two novel highly fluorescent aryl-phenoxy-BTD dyes. Their photophysical properties were evaluated in solution and the results indicate a strong intramolecular charge transfer (ICT) character in the excited state. The luminophore 3a, possessing a donor-BTD-phenoxide architecture, exhibits superior fluorescence quantum yield (0.67) than the designed acceptor-BTD-phenoxide dye (0.06). After electrochemical and photoluminescence characterization of thin films of 3a, an OLED with the configuration ITO/PEDOT:PSS/3a/TPBi/LiF/Al was constructed. This device displayed a green emission centered at 547?nm, with CIE coordinates of (0.40, 0.55). For comparison, an OLED using a previously reported luminescent BTD-pyridyl derivative was also constructed. The OLED made with the phenoxy-BTD derivative operated using less current density and led to higher irradiance and electrical stability, indicating the high potential of ArO-BTD dyes for future application in electroluminescent devices. 相似文献
183.
Mehrdad Khatami Iraj Sharifi Marcos A. L. Nobre Niloofar Zafarnia 《Green Chemistry Letters and Reviews》2018,11(2):125-134
Grass waste was used for transform an inexpensive waste into health. Silver nanoparticles (AgNPs) have been synthesized using waste material (dried grass). The average size of silver nanoparticles observed in transmission electron images was estimated to be about 15?nm. The anticancer, antifungal and antibacterial effect of AgNPs were studied in vitro. The minimum inhibitory concentration of AgNPs against Pseudomonas aeruginosa and Acinetobacter baumannii was calculated about 3?µg/ml. The highest level of inhibitory effect of AgNPs against Fusarium solani was close to 90% at a concentration of 20?μg/ml of AgNPs. An inhibitory effect on the cancer cell growth is reach, by increasing the concentration of AgNPs to 5?µg/ml; the cancer cells’ survival decreases about 30%. Western results showed that the expression of Cyclin D1 protein of MCF-7 cell line decreased after treatment with the effective concentration of AgNPs. 相似文献
184.
García F Goodman JM Kowenicki RA Kuzu I McPartlin M Silva MA Riera L Woods AD Wright DS 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(23):6066-6072
The structures of the host-guest complexes [[[[P(mu-NtBu)]2(mu-NH)]5]I]-.[Li(thf)4]+ [2.I[Li(thf)4]] and [[[P(mu-NtBu)]2(mu-NH)]5].HBr.THF (2.HBr.THF) show that increased distortion of the framework of the pentameric macrocycle [[[P(mu-NtBu)]2(mu-NH)]5] (2) occurs with the larger halide ions. Theoretical studies show that the thermodynamic stabilities of the model host-guest anions [2.X]- (X=Cl, Br, I) are in the order Cl- approximately Br->I-, that is, the reverse of the templating trend observed experimentally. These studies support the view that the selection of the pentamer 2 over the tetramer [[[P(mu-NtBu)]2(mu-NH)]4] (1) is kinetically controlled, a conclusion which is also consistent with the previous observation that the frameworks of 1 and 2 are not in dynamic equilibrium with each other. 相似文献
185.
Daniele R. Nogueira Felipe B. D’Avila Clarice M. B. Rolim Sergio L. Dalmora 《Chromatographia》2007,66(11-12):915-919
A reversed-phase liquid chromatography (RP-LC) method was validated for the determination of rupatadine in pharmaceutical dosage forms. The LC method was carried out on a Gemini C18 column (150 mm × 4.6 mm I.D.), maintained at 30 °C. The mobile phase consisted of ammonium acetate buffer (pH 3.0; 0.01 M) with 0.05% of 1-heptanesulfonic acid–acetonitrile (71.5:28.5, v/v), run at a flow rate of 1.0 mL min?1 and using photodiode array (PDA) detection at 242 nm. The chromatographic separation was obtained with retention time of 5.15 min, and was linear in the range of 0.5–400 μg mL?1 (r 2 = 0.9999). The specificity and stability-indicating capability of the method was proven through the degradation studies and showing also, that there was no interference of the excipients. The accuracy was 100.39% with bias lower than 0.58%. The limits of detection and quantitation were 0.01 and 0.5 μg mL?1, respectively. Moreover, method validation demonstrated acceptable results for precision, sensitivity and robustness. The proposed method was applied for the analysis of pharmaceutical dosage forms assuring the therapeutic efficacy. 相似文献
186.
We carried out the purification of C-phycocyanin and allophycocyanin from Spirulina platensis taking advantage of the adsorption properties of the expanded beds. Initially, phycobiliproteins were released from the microalga
cells by osmotic shock. Next, phycocyanins were recovered by applying the centrifuged cell suspension directly to the anion
exchanger Streamline-DEAE using expanded bed columns, equilibrated with 50 mM sodium phosphate buffer, pH 7.0. After adsorption,
washing was carried out in the expanded-bed mode. Having removed unbound proteins and cellular debris, the bed was allowed
to sediment and phycocyanins rich solution was eluted with a downward flow of 500 mM sodium phosphate buffer, pH 7.0. Finally,
we utilized conventional gel filtration and ion exchange chromatography methods for separation and purification of C-phycocyanin
and allophycocyanin. The purification steps were monitored using sodium dodecyl sulfate-polyacrylamide gel electrophoresis,
and the purity of recovered phycocyanins was confirmed by absorption and emission spectroscopy. The main advantage of this
new method is the high yield achieved in the steps of product extraction and adsorption by expanded bed adsorption, so reducing
both processing times and costs. 相似文献
187.
188.
P
(f) — , f L
p
- , k . f 02k–2 P
(f) 0. 相似文献
189.
Victoria E. González Felipe Medrano Mario Rodríguez Pascal G. Lacroix Victor Barba 《Tetrahedron letters》2014
A new family of luminescent boronates was prepared from reaction of 5-formyl-2-furanboronic acid with 2-aminophenol derivatives. The furan ring-opening was favored by the presence of the boronic acid group. Evaluation of the photophysical characteristics for all compounds showed significant solvatochromic, fluorescent, and NLO properties. 相似文献
190.