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151.
Carmina del Rio Campos Author Vitae Paloma R. Horche Author Vitae Alfredo Martin-Minguez Author Vitae 《Optics Communications》2011,284(5):1346-1353
Due to the fact that a metro network market is very cost sensitive, direct modulated schemes appear attractive. In this paper a CWDM (Coarse Wavelength Division Multiplexing) system is studied in detail by means of an Optical Communication System Design Software; a detailed study of the modulated current shape (exponential, sine and gaussian) for 2.5 Gb/s CWDM Metropolitan Area Networks is performed to evaluate its tolerance to linear impairments such as signal-to-noise-ratio degradation and dispersion. Point-to-point links are investigated and optimum design parameters are obtained. Through extensive sets of simulation results, it is shown that some of these shape pulses are more tolerant to dispersion when compared with conventional gaussian shape pulses. In order to achieve a low Bit Error Rate (BER), different types of optical transmitters are considered including strongly adiabatic and transient chirp dominated Directly Modulated Lasers (DMLs). We have used fibers with different dispersion characteristics, showing that the system performance depends, strongly, on the chosen DML-fiber couple. 相似文献
152.
Salvatore Giovanni De-Simone Guilherme Curty Lechuga Paloma Napoleo-Pêgo Larissa Rodrigues Gomes David William Provance Jr. Vinícius Dias Nirello Ana Carolina Renn Sodero Herbert Leonel de Mattos Guedes 《Molecules (Basel, Switzerland)》2021,26(13)
Introduction: Snakebite envenomation is considered a neglected tropical disease, and SVTLEs critical elements are involved in serious coagulopathies that occur on envenoming. Although some enzymes of this group have been structurally investigated, it is essential to characterize other proteins to better understand their unique properties such as the Lachesis muta rhombeata 47 kDa (Lmr-47) venom serine protease. Methods: The structure of Lmr-47 was studied in solution, using SAXS, DLS, CD, and in silico by homology modeling. Molecular docking experiments simulated 21 competitive inhibitors. Results: At pH 8.0, Lmr-47 has an Rg of 34.5 ± 0.6 Å, Dmax of 130 Å, and SR of 50 Å, according to DLS data. Kratky plot analysis indicates a rigid shape at pH 8.0. Conversely, the pH variation does not change the center of mass’s intrinsic fluorescence, possibly indicating the absence of fluorescent amino acids in the regions affected by pH variation. CD experiments show a substantially random coiled secondary structure not affected by pH. The low-resolution model of Lmr-47 presented a prolate elongated shape at pH 8.0. Using the 3D structure obtained by molecular modeling, docking experiments identified five good and three suitable competitive inhibitors. Conclusion: Together, our work provided insights into the structure of the Lmr-47 and identified inhibitors that may enhance our understanding of thrombin-like family proteins. 相似文献
153.
Paloma Navia Jacobo Troncoso Luis Romaní 《The Journal of chemical thermodynamics》2008,40(11):1607-1611
A new method for determining isobaric thermal expansivity of liquids as a function of temperature and pressure through calorimetric measurements against pressure is described. It is based on a previously reported measurement technique, but due to the different kind of calorimeter and experimental set up, a new calibration procedure was developed. Two isobaric thermal expansivity standards are needed; in this work, with a view on the quality of the available literature data, hexane and water are chosen. The measurements were carried out in the temperature and pressure intervals (278.15 to 348.15) K and (0.5 to 55) MPa for a set of liquids, and experimental values are compared with the available literature data in order to evaluate the precision of the experimental procedure. The analysis of the results reveals that the proposed methodology is highly accurate for isobaric thermal expansivity determination, and it allows obtaining a precise characterisation of the temperature and pressure dependence of this thermodynamic coefficient. 相似文献
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155.
At present, there is a considerable amount of work devoted to the study of the thermophysical properties of pure ionic liquids,
which contrasts with the few data available for their mixtures. One of the most appealing characteristics of ionic liquids
is the capability of subtly changing the chemical structure of the cation and anion in order to design appropriate solvents
for specific applications. Mixtures of ionic liquids increase enormously this specificity, due to the unlimited combinations
that arise from mixing two or more ionic liquids. In this context, the study of the thermophysical properties of these mixtures
is revealed as a fundamental task. In this work the viscosities of the ionic liquid binary mixtures with a common ion ([C6mim] + [C2mim])[BF4], ([C6mim] + [C4mim])[BF4], [C4mim]([BF4] + [MeSO4]) and [C4mim]([PF6] + [BF4]) were determined within the temperature range (298.15–308.15) K. The temperature dependence of the viscosity for pure liquids
is analyzed by means of the Vogel-Tammann-Fulcher equation and several mixing rules are applied for the mixtures. 相似文献
156.
Escudero R Gómez-Gallego M Romano S Fernández I Gutiérrez-Alonso Á Sierra MA López-Rayo S Nadal P Lucena JJ 《Organic & biomolecular chemistry》2012,10(11):2272-2281
In this study we have obtained experimental evidence that confirms the high activity of aquo complexes III and IV towards the enzyme FCR, responsible for the reduction of Fe(III) to Fe(II) in the process of iron acquisition by plants. The in vivo FCR assays in roots of stressed cucumber plants have shown a higher efficiency of the family of complexes III and a striking structure-activity relationship with the nature of the substituent placed in a phenyl group far away from the metal center. The results obtained in this work demonstrate that all the aquo compounds tested interact efficiently with the enzyme FCR and hence constitute a new concept of iron chelates that could be of great use in agronomy. 相似文献
157.
Simó C Pérez P Neusüss C Pelzing M San Román J Gallardo A Cifuentes A 《Electrophoresis》2006,27(11):2250-2258
Analytical characterization of dimethacrylate-tyrosine-lysine-tyrosine (DMTLT, a new biodegradable acrylic cross-linker synthesized at our laboratory) is carried out using CE-MS. DMTLT is a pseudopeptide composed by tyrosine-lysine-tyrosine amino acids linked through urea bonds with two methacrylic groups, one at each end of the molecule, making this compound an excellent cross-linker for polymerization reactions and for obtaining new biodegradable materials. A new CE-MS method is developed for the characterization of DMTLT and its products of degradation after basic hydrolysis. In order to carry out an exhaustive examination of such degradation products methods based on CE coupled to IT and TOF-MS are employed. Based on CE-IT-MS results and the elemental composition of the degradation products obtained by CE-TOF-MS, conclusions on the mechanism and kinetic of hydrolysis of DMTLT are obtained confirming both the usefulness of CE-MS to characterize new biomaterials and the applicability of DMTLT for preparing new biodegradable polymers. These results are corroborated through the CE-MS detection of the identified products of degradation in a dimethyl acrylamide polymer cross-linked with DMTLT. 相似文献
158.
Susana Campuzano Paloma Yáñez-Sedeño José Manuel Pingarrón 《Current Opinion in Electrochemistry》2019
Nowadays, there is increasing demand to overcome the major constraints involved in cumbersome and protracted procedures used in conventional laboratory methods for molecular detection and develop methodologies suitable to near real-time, continuous, and direct monitoring of the target analyte in the analyzed sample at decentralized settings. In this context, biosensors using electrochemistry as transduction technique are particularly attractive to monitor binding-induced changes in the rigidity of a redox-tagged nucleic acid or peptide-switching probes (switch-based biosensors) or a capture antibody attached to an interrogating electrode. Sensors based on biomolecular switches, DNAs, aptamers, and peptides that reversibly shift between two or more conformations (or conformational ensembles) in response to the binding of a specific target ligand have been applied to the determination of a wide range of relevant analytes (nucleic acids, proteins, small molecules, and ions) and are rapid (responding in minutes), sensitive, reagentless, easily reusable, and less prone to fouling issues. They are capable to report in near real time the target binding event without any subsequent processing step, directly in challenging samples or continuously in flowing samples, and even in vivo using affordable and miniaturization-compatible instrumentation. Only a few redox-labeled capture antibody–based immunosensing strategies have been reported to date for the reagentless and continuous electrochemical determination of relevant analytes. 相似文献
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