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排序方式: 共有595条查询结果,搜索用时 31 毫秒
121.
Irene Malpartida Maria Angeles Larrubia Vargas Luis J. Alemany Elisabetta Finocchio Guido Busca 《Applied catalysis. B, Environmental》2008,80(3-4):214-225
Pt–Ba–Al2O3 active and selective for NOx storage and selective reduction to N2 has been prepared and tested. Characterization of the parent Al2O3, Pt–Al2O3 and Ba–Al2O3 materials, as well as of Pt–Ba–Al2O3 catalyst in the oxidized, reduced and sulphated state has been performed by FT-IR spectroscopy of low-temperature adsorbed carbon monoxide and of adsorbed acetonitrile. XRD, TEM and XPS analyses have also been performed. Evidence for the predominance of Ba species, which are highly dispersed on the alumina support surface, and may be carbonated or sulphated, has been provided. Competitive interaction of Pt and Ba species with the surface sites of alumina has also been found. 相似文献
122.
Anodic,cathodic and combined treatments for the electrochemical oxidation of an effluent from the flame retardant industry 总被引:1,自引:0,他引:1
Daniele Montanaro Elisabetta Petrucci Carlo Merli 《Journal of Applied Electrochemistry》2008,38(7):947-954
The electrochemical oxidation of an effluent from the manufacture of phosphorus based flame retardants was studied. To reach
a residual concentration of reduced phosphorus lower than 10 mg L−1, in compliance with Italian law for industrial wastewater disposal, anodic oxidation using a boron-doped diamond (BDD) anode
and electro-Fenton (EF) treatment were tested. The effects of some factors are optimised and a comparison of the reaction
pathways is also presented. A combined treatment using EF with BDD conducted in an undivided cell is shown not to enhance
the data obtained with BDD while a novel combined treatment using EF and BDD in a divided cell shows promising results when
an anionic membrane is used as separation. In this last case the cell operates as two different batch reactors working with
the same current. The anodic compartment, fed with raw effluent, provides partial oxidation, while the cathodic compartment,
fed with the partially anodically oxidised solution, completes the treatment. When the effluent is transferred in the cathodic
compartment, the anodic one is fed with fresh untreated solution. The advantage of this kind of coupling consists in the simultaneity
of the two treatments which allows total oxidation with notable saving of charge and time. 相似文献
123.
Dr. Sofia Gama Dr. Filipa Mendes Dr. Teresa Esteves Dr. Fernanda Marques Dr. António Matos Dr. José Rino Dr. Joana Coimbra Dr. Mauro Ravera Dr. Elisabetta Gabano Dr. Isabel Santos Dr. António Paulo 《Chembiochem : a European journal of chemical biology》2012,13(16):2352-2362
New [PtCl(pz*NN)]n+ complexes anchored by pyrazolyl‐diamine (pz*NN) ligands incorporating anthracenyl or acridine orange DNA‐binding groups have been synthesized so as to obtain compounds that would display synergistic effects between platination and intercalation of DNA. Study of their interaction with supercoiled DNA indicated that the anthracenyl‐containing complex L2Pt displays a covalent type of binding, whereas the acridine orange counterpart L3Pt shows a combination of intercalative and covalent binding modes with a strong contribution from the former. L2Pt showed a very strong cytotoxic effect on ovarian carcinoma cell lines A2780 and A2780cisR, which are, respectively, sensitive to and resistant to cisplatin. In these cell lines, L2Pt is nine to 27 times more cytotoxic than cisplatin. In the sensitive cell line, L3Pt showed a cytotoxic activity similar to that of cisplatin, but like L2Pt was able significantly to overcome cisplatin cross‐resistance. Cell‐uptake studies showed that L2Pt accumulates preferentially in the cytoplasm, whereas L3Pt reaches the cell nucleus more easily, as clearly visualized by time‐lapse confocal imaging of live A2870 cells. Altogether, these findings seem to indicate that interaction with biological targets other than DNA might be involved in the mechanism of action of L2Pt because this compound, despite having a weaker ability to target the cell nucleus than L3Pt , as well as an inferior DNA affinity, is nevertheless more cytotoxic. Furthermore, ultrastructural studies of A2870 cells exposed to L2Pt and L3Pt revealed that these complexes induce different alterations in cell morphology, thus indicating the involvement of different modes of action in cell death. 相似文献
124.
125.
Francesco Todescato Ilaria Fortunati Samuele Gardin Eleonora Garbin Elisabetta Collini Renato Bozio Jacek J. Jasieniak Gioia Della Giustina Giovanna Brusatin Stefano Toffanin Raffaella Signorini 《Advanced functional materials》2012,22(2):337-344
The development of a solution‐deposited up‐converted distributed feedback laser prototype is presented. It employs a sol–gel silica/germania soft‐lithographed microcavity and CdSe–CdZnS–ZnS quantum dot/sol–gel zirconia composites as optical gain material. Characterization of the linear and nonlinear optical properties of quantum dots establishes their high absorption cross‐sections in the one‐ and two‐ photon absorption regimes to be 1 × 10?14 cm2 and 5 × 104 GM, respectively. In addition, ultrafast transient absorption dynamics measurements of the graded seal quantum dots reveal that the Auger recombination lifetime is 220 ps, a value two times higher than that of the corresponding CdSe core. These factors enable the use of such quantum dots as optically pumped gain media, operating in the one‐ and two‐photon absorption regime. The incorporation of CdSe–CdZnS–ZnS quantum dots within a zirconia host matrix affords a quantum‐dot ink that can be directly deposited on our soft‐lithographed distributed feedback grating to form an all‐solution‐processed microcavity laser. 相似文献
126.
Danka Bukvicki Davide Gottardi Amit Kumar Tyagi Milan Veljic Petar D. Marin Ljubodrag Vujisic Maria Elisabetta Guerzoni Lucia Vannini 《LWT》2014
This study was focused on chemical characterisation of liverwort Scapania nemorea extracts and their antimicrobial activity against pathogenic and food-spoiling yeasts and bacteria. The chemical composition of three different extracts of the liverwort S. nemorea was determined by solid phase microextraction gas chromatography-mass spectrometry (SPME GC–MS). The dominant compounds in extracts were sesquiterpenes β-bazzanene (11%, 17.9% and 14.6%), isobazzanene (10.2%, 15.8% and 11.7%) and aromadendrene (8.8%, 12.9% and 10.6%) in the methanol, ethanol and ethyl acetate extracts, respectively. Antimicrobial potential of S. nemorea extracts against food spoiling yeasts and bacteria was determined in vitro by microdilution method. The Minimum Inhibitory Concentration (MIC) varied from 0.5 to 3 mg/mL for bacteria, and from 0.2 to 1 mg/mL for yeasts. Moreover, the combined effects of dry methanol extract of S. nemorea and heat processing on the survival and growth of a spoilage yeast in an apple/orange-based beverage, have been assessed through a Central Composite Design. Changes in color and flavor of the beverages were considered acceptable also after one week of storage at 25 °C. The results provide evidence of antimicrobial potential of S. nemorea extracts and suggest its potential as natural antimicrobial agent for food preservation. 相似文献
127.
Brunella Carratù Amalia Maria Ambruzzi Elena Fedele Elisabetta Sanzini 《Journal of food science》2005,70(6):c373-c375
Human milk is frequently heat‐treated in hospitals, particularly milk that is banked, to destroy contaminating bacteria and viruses, but this treatment simultaneously reduces the content of some vitamins, enzymes, and immunological and nutritional factors. This study was performed to find the optimal conditions for heat treatment. The effects of 2 pasteurization temperatures on levels of protein sulfur amino acids (methionine, cystine) and some free amino acids (taurine, glutamine, glutamic acid) in light of the oxidative instability that occurs especially during thermal treatment were examined. These substances in raw human milk and in milk treated at 56.5 °C and 62.5 °C for 30 min were compared. Samples of mature human milk from all feeds over 24 h were obtained from 13 healthy well‐nourished mothers of term infants. Each sample was divided into 3 parts: raw, treated at 56.5 °C for 30 min, treated at 62.5 °C for 30 min. The results showed that the availability of sulfur amino acids and free taurine is the same after heat treatment, whereas milk processing increased positively the levels of free glutamic acid and glutamine, but there is significance only for glutamine. The mean quantities of considered amino acids were similar in milk treated at the recommended pasteurization temperature (30 min at 62.5 °C) and at 56.5 ° for 30 min. 相似文献
128.
Abstract: Three batches of soft smear‐ripened Taleggio PDO cheese were made in Northern Italy during the summertime 2010. A total of 129 isolates cultured from cheese surface were examined by using PCR‐based methods and sequencing of both the ITS1 region and D1 and D2 domains of the 26S rRNA gene. Sequence analysis of isolates brought to the identification of 6 species: Debaryomyces hansenii, Kluyveromyces lactis, Kluyveromyces marxianus, Yarrowia lipolytica, Pichia guilliermondii, and Torulaspora delbrueckii. Analysis of DNA directly extracted from 45 cheese surfaces permitted to detect 2 additional species Candida sake and Candida etchellsii. D. hansenii was predominant and widespread whereas the other yeast species were detected less frequently. To determine the relationships between yeast community and the environment, 39 isolates from wooden boxes used for dry salting of cheese were analyzed as well. Sequencing of ITS1 region allowed to identify D. hansenii, T. delbrueckii, and K. lactis. ITS1 multiple sequence alignments of D. hansenii detected in wooden boxes showed an in‐del polymorphism at position 169. ITS1 secondary structures of yeasts were modeled to explore new applications of this region for molecular identification purposes. Practical Application: This study used molecular analysis to identify adventitious yeast population present in the surface of Taleggio smear‐ripened cheese. D. hansenii was found predominant in pasteurized milk, in dry salting equipment, and in all cheese samples until the end of ripening. 相似文献
129.
Patrignani F Iucci L Vallicelli M Guerzoni ME Gardini F Lanciotti R 《Meat science》2007,75(4):676-686
The aim of this work was to study the effects of Debaryomyces hansenii and Yarrowia lipolytica strains, used with lactic acid starter cultures (Lactobacillus plantarum), on the manufacture of dried fermented sausages to understand their role on sausage microbial evolution, lipolytic and proteolytic patterns. The inoculation of the yeast strains did not markedly affect the sausage’s microbial flora. The sausages with the yeast strains showed more marked and earlier water activity (aw) reductions. Moreover, the surface inoculation of the yeast strains resulted, at the end of ripening, in more pronounced proteolysis and lipolysis. The lipolytic patterns of the products were affected not only by the yeast strain but also by the level of mincing of the meat mixture used. 相似文献
130.
Antonio Valentoni Sebastiano Garroni Claudio Pistidda Elisabetta Masolo Emilio Napolitano Pietro Moretto Martin Dornheim Gabriele Mulas Stefano Enzo 《International Journal of Hydrogen Energy》2014
In situ two-dimensional synchrotron X-ray powder diffraction investigation combined with Rietveld method data analysis were performed in order to yield a complete and quantitative phases structure evolution of the polycrystalline mixture 2LiNH2 + KBH4 + LiH during H2 desorption. While a first-principles, purely thermodynamics approach of the system predicted a single dehydrogenation step reaction at relatively low temperatures, it is assessed experimentally that the reaction occurs in two steps with first the formation of Li2NH at ca. 230 °C due to the reaction between LiNH2 and LiH plus hydrogen and ammonia evolution, followed by an additional reaction of the resulting phases with KBH4 at 360 °C, which releases hydrogen and leads to the formation of the monoclinic and tetragonal Li3BN2 polymorphs. Besides pointing out possible limits of a purely thermodynamics approach inevitably relying exact knowledge of experimental quantities, it is concluded that before assuming it viable for on-board vehicle use, additional stoichiometries may be worth of investigation in order to assess any existence of lower hydrogen desorption temperature of such system. 相似文献