排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
Maria Jo?o Carrilho Plancha Carmen Mireya Rangel César Augusto Correia de Sequeira 《Journal of Solid State Electrochemistry》2012,16(2):665-671
The (PEO)4ZnCl2 electrolyte (PEO, polyethylene oxide) was studied in view of its potential application in a solid-state rechargeable zinc
cell. The electrochemical stability window was established, and decomposition voltage values between 3.19 (20 °C) and 1.44 V
(150 °C) were estimated. Cyclic voltammetry studies using a Pt/(PEO)4ZnCl2/Pt cell indicated reversibility of the Zn2+/Zn couple at the electrode/electrolyte interface. Laboratory cells Zn(−)/(PEO)4ZnCl2/Nb2O5(+) were assembled and studied at 55 °C, under various discharge current densities. Results of cell discharge profiles, capacity
values, charge–discharge cycles and cell stabilities are reported. 相似文献
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Onchoke KK Dutta PK Parks ME Martinez MN 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,81(1):162-171
The molecular geometries, vibrational and UV-vis spectra of 9,10-dihydrobenzo(a)pyrene-7(8H)-one (9,10-H(2)BaP) and 7,8,9,10-tetrahydrobenzo(a)pyrene (7,8,9,10-H(4)BaP) were investigated using density functional theory (DFT-B3LYP), with the triple-ζ 6-311+G(d,p) and Dunning's cc-pVTZ basis sets. From the comparison of infrared experimental and calculated infrared, and Raman data comprehensive assignments are made. The calculated infrared frequencies below 1800 cm(-1) are in good agreement with experimental data, with an average deviation of <4 cm(-1). Using the B3LYP/6-311+G(d,p)//TD-B3LYP/6-311G(d,p) level of theory, transition energies, and oscillator strengths of the 30 lowest electronic absorption bands are assigned to π-π* transitions, with good qualitative agreement between experimental and simulated absorption data. In addition, the HOMO-LUMO gaps and their chemical hardness were analyzed. 相似文献
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Daniela Zarzosa-Moreno Christian Avalos-Gmez Luisa Sofía Ramírez-Texcalco Erick Torres-Lpez Ricardo Ramírez-Mondragn Juan Omar Hernndez-Ramírez Jesús Serrano-Luna Mireya de la Garza 《Molecules (Basel, Switzerland)》2020,25(24)
Due to the emergence of multidrug-resistant pathogens, it is necessary to develop options to fight infections caused by these agents. Lactoferrin (Lf) is a cationic nonheme multifunctional glycoprotein of the innate immune system of mammals that provides numerous benefits. Lf is bacteriostatic and/or bactericidal, can stimulate cell proliferation and differentiation, facilitate iron absorption, improve neural development and cognition, promote bone growth, prevent cancer and exert anti-inflammatory and immunoregulatory effects. Lactoferrin is present in colostrum and milk and is also produced by the secondary granules of polymorphonuclear leukocytes, which store this glycoprotein and release it at sites of infection. Lf is also present in many fluids and exocrine secretions, on the surfaces of the digestive, respiratory and reproductive systems that are commonly exposed to pathogens. Apo-Lf (an iron-free molecule) can be microbiostatic due to its ability to capture ferric iron, blocking the availability of host iron to pathogens. However, apo-Lf is mostly microbicidal via its interaction with the microbial surface, causing membrane damage and altering its permeability function. Lf can inhibit viral entry by binding to cell receptors or viral particles. Lf is also able to counter different important mechanisms evolved by microbial pathogens to infect and invade the host, such as adherence, colonization, invasion, production of biofilms and production of virulence factors such as proteases and toxins. Lf can also cause mitochondrial and caspase-dependent regulated cell death and apoptosis-like in pathogenic yeasts. All of these mechanisms are important targets for treatment with Lf. Holo-Lf (the iron-saturated molecule) can contain up to two ferric ions and can also be microbicidal against some pathogens. On the other hand, lactoferricins (Lfcins) are peptides derived from the N-terminus of Lf that are produced by proteolysis with pepsin under acidic conditions, and they cause similar effects on pathogens to those caused by the parental Lf. Synthetic analog peptides comprising the N-terminus Lf region similarly exhibit potent antimicrobial properties. Importantly, there are no reported pathogens that are resistant to Lf and Lfcins; in addition, Lf and Lfcins have shown a synergistic effect with antimicrobial and antiviral drugs. Due to the Lf properties being microbiostatic, microbicidal, anti-inflammatory and an immune modulator, it represents an excellent natural alternative either alone or as adjuvant in the combat to antibiotic multidrug-resistant bacteria and other pathogens. This review aimed to evaluate the data that appeared in the literature about the effects of Lf and its derived peptides on pathogenic bacteria, protozoa, fungi and viruses and how Lf and Lfcins inhibit the mechanisms developed by these pathogens to cause disease. 相似文献
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Mireya Matos Ruiz Jean Yves Cavaill Alain Dufresne Christian Graillat Jean‐Franois Grard 《Macromolecular Symposia》2001,169(1):211-222
New nanocomposites based on a waterborne epoxy emulsion and a suspension of cellulose crystallites were prepared by film casting in order to obtain coatings displaying both flexibility and stiffness. Tunicin cellulose whiskers are attractive reinforcing fillers due to their high aspect ratio, large interface area, and, significant mechanical properties). Typical processing problems for this type of composite are related to high viscosity values of filled polymers in the in the molten state, the incompatibility between hydrophobic matrices and hydrophilic cellulose and the formation of hydrogen bonds between cellulose of this type of natural fibres in an epoxy matrix. The aim of this work is to solve some of the problems above mentioned by selecting the nature of the components used for coating synthesis film processing. The dynamic mechanical properties display an important improvement of the composite modulus in the rubbery state of the matrix at low concentrations of fillers, which can not be expected other cellulose based fibers. 相似文献
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Oehlers L Mazzitelli CL Brodbelt JS Rodriguez M Kerwin S 《Journal of the American Society for Mass Spectrometry》2004,15(11):1593-1603
Electrospray ionization mass spectrometry is used to compare the metal ion binding and metal-mediated DNA binding of benzoxazole (1, 2, 3, 4) and benzimidazole (5) compounds and to elucidate the putative binding modes and stoichiometries. The observed metal versus non-metal-mediated DNA binding, as well as the specificity of DNA binding, is correlated with the biological activities of the analogs. The ESI-MS spectra for the antibacterial benzoxazole and benzimidazole analogs 4 and 5 demonstrated non-specific and non-metal-mediated binding to DNA, with the appearance of DNA complexes containing multiple ligands. The anticancer analog 2 demonstrates a clear preference for metal-mediated DNA interactions, with an apparent selectivity for Ni2+ -mediated binding over the more physiologically relevant Mg2+ or Zn2+ cations. Complexation between DNA and the biologically inactive analog 1 was not observed, either in the absence or presence of metal cations. 相似文献
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Maria Luisa Cubeiro Hernan Morales Mireya R. Goldwasser Maria Josefina Pérez-Zurita Fernando González-Jiménez 《Reaction Kinetics and Catalysis Letters》2000,69(2):259-264
Catalysts containing copper, zinc and aluminium oxides are used extensively in hydrogenation reactions, low temperature water-gas shift and low pressure methanol synthesis processes. In the present study, the effects of certain pertinent preparation parameters on catalysts' activity have been studied, applying the saturated fractional factorial experimental design method. The influence of time and temperature of calcination, aging time, the method of mixing of reactant solutions, the nature of the precipitant and the molar ratio of the latter to metal nitrates have been investigated. The catalysts prepared, using sodium carbonate showed higher activities relative to those synthesized by applying sodium hydrogen carbonate. Higher temperatures and longer time of calcination have profound effects on the activity of catalysts prepared, using sodium hydrogen carbonate. Shorter aging times and higher molar ratios of precipitant to metal nitrates promoted the activity of catalysts prepared by sodium carbonate. In case of catalysts synthesized, using sodium hydrogen carbonate as the precipitant, the aging time should be maintained as short as possible in order the catalysts to acquire higher activities. 相似文献
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Paulina Dreyse Mireya Santander-Nelli David Zambrano Luis Rosales Luis Sanhueza 《International journal of quantum chemistry》2020,120(12):e26167
The structures and electronic properties of a series of cyclometalated Ir(III) complexes with substituted dppz ancillary ligand (dppz: dipyrido[3,2-a:2′,3′-c]phenazine) including tert-butyl, pyrrolidine ring, and alkoxys substituents as donor group have been theoretically study. With the aim of highlight the attractive qualities of each system for their use as luminescent material, the effects of the electron-donor substituents onto dppz was evaluated on the structural, charge transport, absorption, and phosphorescent properties. The effect of the substituent was studied on the modulation of the bright and dark triplet states. Main results show that ortho-methoxy and tert-butyl substituents act as lower electron-donating groups, then, efficient electron donation ability was displayed with alkoxy (ethoxy and propoxy) substituents. The best performance was found in a complex with pyrrolidine ring according since their phosphorescence is favored, highlighting their larger electric transition dipole moment value, proposing this system as potential candidate to LEC technology. 相似文献
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Milnes PJ McKee ML Bath J Song L Stulz E Turberfield AJ O'Reilly RK 《Chemical communications (Cambridge, England)》2012,48(45):5614-5616
Using a strand exchange mechanism we have prepared, by DNA templated chemistry, two 10-mers with defined and tunable monomer sequences. An optimized reaction protocol achieves 85% coupling yield per step, demonstrating that DNA-templated chemistry is a powerful tool for the synthesis of macromolecules with full sequence control. 相似文献
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