Search results for "tipo"
showing 10 items of 704 documents
Finite-Size and Illumination Conditions Effects in All-Dielectric Metasurfaces
2022
Dielectric metasurfaces have emerged as a promising alternative to their plasmonic counterparts due to lower ohmic losses, which hinder sensing applications and nonlinear frequency conversion, and their larger flexibility to shape the emission pattern in the visible regime. To date, the computational cost of full-wave numerical simulations has forced the exploitation of the Floquet theorem, which implies infinitely periodic structures, in designing such devices. In this work, we show the potential pitfalls of this approach when considering finite-size metasurfaces and beam-like illumination conditions, in contrast to the typical infinite plane-wave illumination compatible with the Floquet t…
Transport of C(4)-dicarboxylates in Wolinella succinogenes.
2000
ABSTRACT C 4 -dicarboxylate transport is a prerequisite for anaerobic respiration with fumarate in Wolinella succinogenes , since the substrate site of fumarate reductase is oriented towards the cytoplasmic side of the membrane. W. succinogenes was found to transport C 4 -dicarboxylates (fumarate, succinate, malate, and aspartate) across the cytoplasmic membrane by antiport and uniport mechanisms. The electrogenic uniport resulted in dicarboxylate accumulation driven by anaerobic respiration. The molar ratio of internal to external dicarboxylate concentration was up to 10 3 . The dicarboxylate antiport was either electrogenic or electroneutral. The electroneutral antiport required the prese…
Experimental verification of position-dependent angular-momentum selection rules for absorption of twisted light by a bound electron
2018
We analyze the multipole excitation of atoms with twisted light, i.e., by a vortex light field that carries orbital angular momentum. A single trapped $^{40}$Ca$^+$ ion serves as a localized and positioned probe of the exciting field. We drive the $S_{1/2} \to D_{5/2}$ transition and observe the relative strengths of different transitions, depending on the ion's transversal position with respect to the center of the vortex light field. On the other hand, transition amplitudes are calculated for a twisted light field in form of a Bessel beam, a Bessel-Gauss and a Gauss-Laguerre mode. Analyzing experimental obtained transition amplitudes we find agreement with the theoretical predictions at a…
Ansia e comportamento di tipo A nei soggetti con Glaucoma cronico ad angolo aperto
2012
DctA- and Dcu-independent transport of succinate in Escherichia coli : contribution of diffusion and of alternative carriers
2001
Quintuple mutants of Escherichia coli deficient in the C4-dicarboxylate carriers of aerobic and anaerobic metabolism (DctA, DcuA, DcuB, DcuC, and the DcuC homolog DcuD, or the citrate/succinate antiporter CitT) showed only poor growth on succinate (or other C4-dicarboxylates) under oxic conditions. At acidic pH (pH 6) the mutants regained aerobic growth on succinate, but not on fumarate. Succinate uptake by the mutants could not be saturated at physiological succinate concentrations (≤5 mM), in contrast to the wild-type, which had a K m for succinate of 50 µM and a V max of 35 U/g dry weight at pH 6. At high substrate concentrations, the mutants showed transport activities (32 U/g dry weigh…
The Fumarate/Succinate Antiporter DcuB of Escherichia coli Is a Bifunctional Protein with Sites for Regulation of DcuS-dependent Gene Expression
2008
DcuB of Escherichia coli catalyzes C4-dicarboxylate/succinate antiport during growth by fumarate respiration. The expression of genes of fumarate respiration, including the genes for DcuB (dcuB) and fumarate reductase (frdABCD) is transcriptionally activated by C4-dicarboxylates via the DcuS-DcuR two-component system, comprising the sensor kinase DcuS, which contains a periplasmic sensing domain for C4-dicarboxylates. Deletion or inactivation of dcuB caused constitutive expression of DcuS-regulated genes in the absence of C4-dicarboxylates. The effect was specific for DcuB and not observed after inactivation of the homologous DcuA or the more distantly related DcuC transporter. Random and s…
Interaction of theEscherichia colitransporter DctA with the sensor kinase DcuS: presence of functional DctA/DcuS sensor units
2012
The aerobic Escherichia coli C(4) -dicarboxylate transporter DctA and the anaerobic fumarate/succinate antiporter DcuB function as obligate co-sensors of the fumarate responsive sensor kinase DcuS under aerobic or anaerobic conditions respectively. Overproduction under anaerobic conditions allowed DctA to replace DcuB in co-sensing, indicating their functional equivalence in this capacity. In vivo interaction studies between DctA and DcuS using FRET or a bacterial two-hybrid system (BACTH) demonstrated their interaction. DctA-YFP bound to an affinity column and was able to retain DcuS. DctA shows substantial sequence and secondary structure conservation to Glt(Ph), the Na(+)/glutamate sympo…
The "Historia de la doncella Teodor" in Burgos’ Printing Press: Regarding a New Edition from Juan de Junta’s Workshop, c. 1535-1540
2020
En este trabajo se da noticia y se lleva a cabo el estudio tipobibliográfico de una edición sine notis de la Historia de la doncella Teodor. El análisis permite identificar la impresión en Burgos en el taller de Juan de Junta, c. 1535-1540. El rasgo material que singulariza este impreso es que la última hoja del primer cuaderno ha sido remedada por una copia manuscrita que no solo reproduce la tipografía original, sino también, a plumilla, las estampas. El estudio textual e iconográfico nos permitirá identificar la fuente del folio contrahecho.
Otra visión de la historia del mueble. La evolución técnica, base de la formal
2008
La evolución del mobiliario no sólo está condicionada por la transformación en los estilos de vida, sino también por el desarrollo de técnicas de elaboración de la madera. Este artículo está dirigido a aquellos que investigan o se aproximan al mobiliario y las artes decorativas, con la intención de proporcionar una herramienta para la comprensión de la evolución constructiva y de las técnicas decorativas. (A)
Per una archeologia dello spazio sepolcrale
2021
Attraverso questo contributo si intende sviluppare una sperimentale “misurazione critica”, di tipo strutturalista, finalizzata all’individuazione dei “principi formali” sottesi al progetto architettonico della tomba Brion. Sulla base delle argomentazioni teoriche elaborate da Vittorio Ugo in riferimento al problema degli archetipi dell’architettura, si propone una “archeo-logia” del complesso sepolcrale, con lo scopo di effettuare una “classificazione” delle forme interne al monumento. Due le macro-famiglie alle quali si fanno appartenere gli archetipi individuati: quella dell’“archeologia della natura” e quella dell’ “archeologia dell’architettura.