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排序方式: 共有166条查询结果,搜索用时 46 毫秒
71.
Juan F. Espinosa Paloma Vidal Teodor Parella Sergi Gil 《Magnetic resonance in chemistry : MRC》2011,49(8):502-507
The SELective INverse detection of carbon–proton CORrelation pulse sequence that yields a 1D spectrum of a proton directly bonded to a selected carbon resonance has been converted into a proton and carbon double‐selective variant that provides a 1H spectrum of a selected proton that is long‐range coupled to a specific carbon resonance. The resulting 1D proton multiplet exhibits a pure absorptive in‐phase lineshape for precise measurement of specific long‐range proton–carbon coupling constants in small organic molecules at natural abundance. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
72.
73.
Tristan Maschmeyer Paloma L. Prieto Shad Grunert Jason E. Hein 《Magnetic resonance in chemistry : MRC》2020,58(12):1234-1248
This study focused on fundamental data acquisition parameter selection for a benchtop nuclear magnetic resonance (NMR) system with continuous flow, applicable for reaction monitoring. The effect of flow rate on the mixing behaviors within a flow cell was observed, along with an exponential decay relationship between flow rate and the apparent spin–lattice relaxation time (T1*) of benzaldehyde. We also monitored sensitivity (as determined by signal-to-noise ratios; SNRs) under various flow rates, analyte concentrations, and temperatures of the analyte flask. Results suggest that a maximum SNR can be achieved with low to medium flow rates and higher analyte concentrations. This was consistent with data collected with parameters that promote either slow or fast data acquisition. We further consider the effect of these conditions on the analyte's residence time, T1*, and magnetic field inhomogeneity that is a product of continuous flow. Altogether, our results demonstrate how fundamental acquisition parameters can be manipulated to achieve optimal data acquisition in continuous-flow NMR systems. 相似文献
74.
Mercedes Ballesteros Felicia Sáez Ignacio Ballesteros Paloma Manzanares Maria Jose Negro Jose Maria Martínez Rafael Castañeda Jose Miguel Oliva Dominguez 《Applied biochemistry and biotechnology》2010,161(1-8):423-431
In this work, the use of organic fraction from municipal solid waste (MSW) as substrate for ethanol production based on enzymatic hydrolysis was evaluated. MSW was subjected to a thermal pretreatment (active hygienization) at 160?°C from 5 to 50 min. The organic fiber obtained after 30 min was used as substrate in a simultaneous saccharification and fermentation (SSF) and fed-batch SSF process using cellulases and amylases. In a fed-batch mode with 25% (w/w) substrate loading, final ethanol concentration of 30 g/L was achieved (60% of theoretical). In these conditions, more than 160 L of ethanol per ton of dry matter could be produced from the organic fraction of MSW. 相似文献
75.
George E. Magoulas Pantelis Afroudakis Kalliopi Georgikopoulou Marina Roussaki Chiara Borsari Theano Fotopoulou Nuno Santarem Emile Barrias Paloma Tejera Nevado Julia Hachenberg Eugenia Bifeld Bernhard Ellinger Maria Kuzikov Irini Fragiadaki Effie Scoulica Joachim Clos Sheraz Gul Maria Paola Costi Wanderley de Souza Kyriakos C. Prousis Anabela Cordeiro da Silva Theodora Calogeropoulou 《Molecules (Basel, Switzerland)》2021,26(14)
A library of seventeen novel ether phospholipid analogues, containing 5-membered heterocyclic rings (1,2,3-triazolyl, isoxazolyl, 1,3,4-oxadiazolyl and 1,2,4-oxadiazolyl) in the lipid portion were designed and synthesized aiming to identify optimised miltefosine analogues. The compounds were evaluated for their in vitro antiparasitic activity against Leishmania infantum and Leishmania donovani intracellular amastigotes, against Trypanosoma brucei brucei and against different developmental stages of Trypanosoma cruzi. The nature of the substituents of the heterocyclic ring (tail) and the oligomethylene spacer between the head group and the heterocyclic ring was found to affect the activity and toxicity of these compounds leading to a significantly improved understanding of their structure–activity relationships. The early ADMET profile of the new derivatives did not reveal major liabilities for the potent compounds. The 1,2,3-triazole derivative 27 substituted by a decyl tail, an undecyl spacer and a choline head group exhibited broad spectrum antiparasitic activity. It possessed low micromolar activity against the intracellular amastigotes of two L. infantum strains and T. cruzi Y strain epimastigotes, intracellular amastigotes and trypomastigotes, while its cytotoxicity concentration (CC50) against THP-1 macrophages ranged between 50 and 100 μM. Altogether, our work paves the way for the development of improved ether phospholipid derivatives to control neglected tropical diseases. 相似文献
76.
Zanin JL de Carvalho BA Martineli PS dos Santos MH Lago JH Sartorelli P Viegas C Soares MG 《Molecules (Basel, Switzerland)》2012,17(7):7887-7902
The genus Caesalpinia (Caesalpiniaceae) has more than 500 species, many of which have not yet been investigated for potential pharmacological activity. Several classes of chemical compounds, such as flavonoids, diterpenes, and steroids, have been isolated from various species of the genus Caesalpinia. It has been reported in the literature that these species exhibit a wide range of pharmacological properties, including antiulcer, anticancer, antidiabetic, anti-inflammatory, antimicrobial, and antirheumatic activities that have proven to be efficacious in ethnomedicinal practices. In this review we present chemical and pharmacological data from recent phytochemical studies on various plants of the genus Caesalpinia. 相似文献
77.
Jorge Casalderrey-Solana José Guilherme Milhano Paloma Quiroga-Arias 《Physics letters. [Part B]》2012
We study the time structure of vacuum jet evolution via a simple uncertainty principle estimate in the kinematic range explored by current heavy ion collisions at the LHC. We observe that a large fraction of the partonic splittings occur at large times, of the order of several fm. We compare the time distribution of vacuum splittings with the distribution of path lengths traversed by jets in a heavy ion collision. We find that if no medium induced modification of the jet dynamics were present, a very large fraction (larger than 80% for inclusive jets) of the jet splittings would occur outside of the medium. We confront this observation with current available data on jet properties in heavy ion collisions and discuss its implications for the dynamics of jet–medium interactions. 相似文献
78.
This paper describes the applications of a multipurpose holographic device in optical networks with Coarse and Dense Wavelength
Division Multiplexing (CWDM/ DWDM) technologies. In its basic structure, it can operate as a tunable wavelength filter, wavelength
multiplexer or λ router. By using a more complex structure, the device works as OADM (Optical Add Drop Multiplexer) or OS (Optical Switch).
Some simulations of the basic devices, from the optical transmission point of view, are made to match the transmission parameters
for the application in optical networks. Performance parameters of the device, like switching time, losses, cross-talk or
polarization insensitivity are analyzed and compared with other multiplexing or switching technologies. To complete the review
of these components, a study of computer generated holograms (CGH) design is carried out. The results are used in the design
of holographic devices to perform different applications: in Metro networks, where a design of a holographic device with wavelength
conversion and routing is analyzed, or, in Access Networks like a tunable filter or demultiplexer in Fiber to the Home/Business
(FTTH/FTTB) topologies. 相似文献
79.
Carmina del Río Campos Author Vitae Paloma R. Horche Author Vitae 《Optics Communications》2010,283(15):3058-3066
Direct Modulation Lasers (DMLs) have attracted increased attention during the past few years because of their intrinsic simplicity and cost-effectiveness, especially when applied to WDM metro and access networks. However, the output power waveform from a directly modulated laser is not an exact replica of the modulation current and its instantaneous optical frequency varies with time depending on the changes in optical power and the extinction ratio (ER) (an effect also known as frequency chirp). In this work, using an Optical Communication System Design Software, we have studied a directly modulated WDM 10 Gb/s system which transmission performance depends strongly on DML characteristics; simulation results have provided supplementary details about the effects of DML type (adiabatic or transient chirp dominated) as well as the effects of the optical output power. These details can provide useful design guidelines for constructing a WDM metro network. 相似文献
80.
John N. Low Paloma Arranz Justo Cobo M. Angeles Fontecha M. Luz Godino Rafael Lpez Debbie Cannon Antonio Quesada Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(6):680-682
In the title compound, [Ca(C9H11N6O5)2(H2O)3], the Ca atom lies on a twofold rotation axis in C2/c and the three water molecules are all disordered, each over two sites having equal occupancy. The anion acts as a bridging ligand between pairs of Ca sites on the same twofold axis, thus forming a one‐dimensional coordination polymer, with the chains lying along the twofold axes. These chains are linked by multiple O—H?O and N—H?O hydrogen bonds into a single three‐dimensional framework. 相似文献