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101.
Mendoza-Ruiz Ernan Adalid Mentado-Morales Juan Flores-Segura Henoc 《Journal of Thermal Analysis and Calorimetry》2019,135(4):2337-2345
Journal of Thermal Analysis and Calorimetry - The values of the standard molar energies of combustion of Tetra-N-phenylbenzidine and 4,4′-Bis(N-carbazolyl)-1,1′-biphenyl in solid phase... 相似文献
102.
E. Camarillo H. Murrieta J.M. Hernandez R. Zoilo M.C. Flores T.P.J. Han F. Jaque 《Journal of luminescence》2008,128(5-6):747-750
Lithium niobate (LiNbO3) crystals doped with chromium ions show a clear green colouring reflecting the absorption profile of the dominating [Cr]Li defect centres. A significant change in its colouration takes place when it is co-doped with other valency impurities such as Mg2+, Sc3+ and W6+, above a certain threshold concentration. This concentration singularity has been attributed to the formation of [Cr]Nb centres coexisting with the [Cr]Li centres.In this work, we extended the investigation on the effect of co-dopant ions in Cr:LiNbO3 to tetravalent cation such as GeO2. A singularity in the relative intensity of the 4A2→4T1 and 4A2→4T2 absorption band was observed for a concentration of ~1.5 mol%, compared with 4.5 mol% for Mg2+. The photoluminescence emission spectra also reveal a new emission band, at a lower energy than the [Cr]Li centre, corresponding to this threshold concentration. A charge compensation model is proposed to explain the role of cation impurities and results are compared with those of other valence impurities. 相似文献
103.
Hybrid catalysts containing CuO-ZnO or CuO-ZnO-Al2O3 as the metallic component and the zeolite H-ferrierite as support were prepared by both the coprecipitation-impregnation and coprecipitation-sedimentation methods. They were characterized by XRD, BET, and TEM. Aluminum was added to the metallic component, and the effects on the hybrid catalyst properties were studied. The metallic component blocked the zeolite micropore volume, and spaces were created between agglomerate particles of the first component, increasing mesopore volume. Aluminum introduction at a Cu/Zn/Al ratio of 55/30/15 favored the formation of hydrotalcite as a precursor to CuO/ZnO/Al2O3. In this case, small, highly dispersed particles of these oxides were obtained. In the coprecipitation-impregnation method, greater contact between the H-ferrierite zeolite and the metallic component was observed. 相似文献
104.
J.C. Flores V. Torres M. Popa D. Crespo J.M. Calderón-Moreno 《Journal of Non》2008,354(52-54):5435-5439
We prepared SiO2@Ag core–shell nanospheres: silver nanoparticles (~4 ± 2 nm in diameter) coated silica nanospheres (~50 ± 10 nm in diameter). The preparation route is a modification of the Stöber method, and involves the preparation of homogeneous silica spheres at room temperature, combined with the deposition of silver nanoparticles from Ag+ in solution, by using water/ethanol mixtures, tetraethyl-orthosilicate as Si source and silver nitrate as Ag source in a single-pot wet chemical route without an added coupling agent or surface modification, which leads to the formation of core@shell homogeneous nanospheres. We present the preparation and characterization of the SiO2@Ag core–shell nanospheres and also of bare silica spheres in the absence of silver, and propose a reaction mechanism for the formation of the core–shell structure. 相似文献
105.
Giustino Orlando Annalisa Chiavaroli Sabrina Adorisio Domenico V. Delfino Luigi Brunetti Lucia Recinella Sheila Leone Gokhan Zengin Alessandra Acquaviva Paola Angelini Giancarlo Angeles Flores Roberto Venanzoni Simonetta Cristina Di Simone Francesca Di Corpo Andrei Mocan Luigi Menghini Claudio Ferrante 《Molecules (Basel, Switzerland)》2021,26(15)
Prunus mahaleb L. fruit has long been used in the production of traditional liqueurs. The fruit also displayed scavenging and reducing activity, in vitro. The present study focused on unravelling peripheral and central protective effects, antimicrobial but also anti-COVID-19 properties exerted by the water extract of P. mahaleb. Anti-inflammatory effects were studied in isolated mouse colons exposed to lipopolysaccharide. Neuroprotection, measured as a blunting effect on hydrogen-peroxide-induced dopamine turnover, was investigated in hypothalamic HypoE22 cells. Antimicrobial effects were tested against different Gram+ and Gram- bacterial strains. Whereas anti-COVID-19 activity was studied in lung adenocarcinoma H1299 cells, where the gene expression of ACE2 and TMPRSS2 was measured after extract treatment. The bacteriostatic effects induced on Gram+ and Gram- strains, together with the inhibition of COX-2, TNFα, HIF1α, and VEGFA in the colon, suggest the potential of P. mahaleb water extract in contrasting the clinical symptoms related to ulcerative colitis. The inhibition of the hydrogen peroxide-induced DOPAC/DA ratio indicates promising neuroprotective effects. Finally, the downregulation of the gene expression of ACE2 and TMPRSS2 in H1299 cells, suggests the potential to inhibit SARS-CoV-2 virus entry in the human host. Overall, the results support the valorization of the local cultivation of P. mahaleb. 相似文献
106.
Allison Leyton Michael Araya Fadia Tala Liset Flores María Elena Lienqueo Carolina Shene 《Molecules (Basel, Switzerland)》2021,26(8)
Seaweed processing generates liquid fraction residual that could be used as a low-cost nutrient source for microbial production of metabolites. The Rhodotorula strain is able to produce antimicrobial compounds known as sophorolipids. Our aim was to evaluate sophorolipid production, with antibacterial activity, by marine Rhodotorula rubra using liquid fraction residual (LFR) from the brown seaweed Macrocystis pyrifera as the nutrient source. LFR having a composition of 32% w/w carbohydrate, 1% w/w lipids, 15% w/w protein and 52% w/w ash. The best culture condition for sophorolipid production was LFR 40% v/v, without yeast extract, artificial seawater 80% v/v at 15 °C by 3 growth days, with the antibacterial activity of 24.4 ± 3.1 % on Escherichia coli and 21.1 ± 3.8 % on Staphylococcus aureus. It was possible to identify mono-acetylated acidic and methyl ester acidic sophorolipid. These compounds possess potential as pathogen controllers for application in the food industry. 相似文献
107.
Maribel Rodríguez‐Aguilar Sofía Ramírez‐García Cesar Ilizaliturri‐Hernndez Alejandro Gmez‐Gmez Evelyn Van‐Brussel Fernando Díaz‐Barriga Susanna Medellín‐Garibay Rogelio Flores‐Ramírez 《Biomedical chromatography : BMC》2019,33(12)
An analytical method to identify volatile organic compounds (VOCs) in the exhaled breath from patients with a diagnosis of chronic obstructive pulmonary disease (COPD) using a ultrafast gas chromatography system equipped with an electronic nose detector (FGC eNose) has been developed. A prospective study was performed in 23 COPD patients and 33 healthy volunteers; exhalation breathing tests were performed with Tedlar bags. Each sample was analyzed by FCG eNose and the identification of VOCs was based on the Kovats index. Raw data were reduced by principal component analysis (PCA) and canonical discriminant analysis [canonical analysis of principal coordinates (CAP)]. The FCG eNose technology was able to identify 17 VOCs that distinguish COPD patients from healthy volunteers. At all stages of PCA and CAP the discrimination between groups was obvious. Chemical prints were correctly classified up to 82.2%, and were matched with 78.9% of the VOCs detected in the exhaled breath samples. Receiver operating characteristic curve analysis indicated the sensitivity and specificity to be 96% and 91%, respectively. This pilot study demonstrates that FGC eNose is a useful tool to identify VOCs as biomarkers in exhaled breath from COPD patients. Further studies should be performed to enhance the clinical relevance of this quick and ease methodology for COPD diagnosis. 相似文献
108.
109.
Ramos Fernando Flores Henoc Camarillo E. Adriana Ledo J. Manuel 《Structural chemistry》2022,33(2):379-388
Structural Chemistry - In the present work, the energy contribution of the sulfur atom in a heterocycle and in a disulfide bond in solid and gas phases was calculated. To achieve this goal,... 相似文献
110.
John S. C. Kearney Miglė Graužinytė Dr. Dean Smith Daniel Sneed Christian Childs Jasmine Hinton Dr. Changyong Park Dr. Jesse S. Smith Dr. Eunja Kim Samuel D. S. Fitch Prof. Dr. Andrew L. Hector Prof. Dr. Chris J. Pickard Dr. José A. Flores‐Livas Prof. Dr. Ashkan Salamat 《Angewandte Chemie (International ed. in English)》2018,57(36):11623-11628
The application of pressure allows systematic tuning of the charge density of a material cleanly, that is, without changes to the chemical composition via dopants, and exploratory high‐pressure experiments can inform the design of bulk syntheses of materials that benefit from their properties under compression. The electronic and structural response of semiconducting tin nitride Sn3N4 under compression is now reported. A continuous opening of the optical band gap was observed from 1.3 eV to 3.0 eV over a range of 100 GPa, a 540 nm blue‐shift spanning the entire visible spectrum. The pressure‐mediated band gap opening is general to this material across numerous high‐density polymorphs, implicating the predominant ionic bonding in the material as the cause. The rate of decompression to ambient conditions permits access to recoverable metastable states with varying band gaps energies, opening the possibility of pressure‐tuneable electronic properties for future applications. 相似文献