1,815 research outputs found
Highly enantiospecific oxyfunctionalization of nonactivated hydrocarbon sites by perfluoro-cis-2-n-butyl-3-n-propyloxaziridine
No full textNonactivated hydrocarbon sites of enantiopure compounds are oxyfunctionalized enantiospecifically by perfluoro-cis-2-n-butyl-3-n-propyloxaziridine under remarkably mild reaction conditions. The reaction occurs with retention of configuration at the oxidized stereogenic center, and the enantiospecificity is highly independent from both the carbon framework of the substrate and the presence of functional groups
The fluorous effect in biomolecular applications
No full textFrom being a niche area only a few decades ago, fluorous chemistry has gained momentum and is, nowadays, a fervent area of research. It has brought forth, in fact, numerous applicative innovations that stretch among different fields: from catalysis to separation science, from supramolecular to materials and analytical chemistry. Recently, the unique features of perfluorinated compounds have reached the attention of the biochemists' audience. This tutorial review introduces the basic concepts of fluorous chemistry and illustrates its main biomolecular applications. Special attention has been given to fluorous microarrays and their combination with Mass-Spectroscopy (MS) techniques, to protein properties modification by the introduction of local fluorous domains, and to the most recent applications of 19 F-Magnetic Resonance Imaging ((19)F-MRI)
PAI-1 inhibits urokinase-induced chemotaxis by internalizing the urokinase receptor
No full textAbstractPAI-1 (plasminogen activator inhibitor-1) binds the urokinase-type plasminogen activator (uPA) and causes its degradation via its receptor uPAR and low-density lipoprotein receptor-related protein (LRP). While both uPA and PAI-1 are chemoattractants, we find that a preformed uPA–PAI-1 complex has no chemotactic activity and that PAI-1 inhibits uPA-induced chemotaxis. The inhibitory effect of PAI-1 on uPA-dependent chemotaxis is reversed when uPAR internalization is inhibited by the 39 kDa receptor-associated protein or by anti-LRP antibodies. Under the same conditions, the uPA–PAI-1 complex is turned into a chemoattractant causing cytoskeleton reorganization and extracellular-regulated kinase/mitogen-activated protein kinases activation. Thus, uPAR internalization by PAI-1 regulates cell migration
Monolithic time-to-amplitude converter for photon timing applications
No full textIn the last years Time-Correlated Single-Photon Counting (TCSPC) has increasingly been used in many different scientific applications (e.g.: single molecule spectroscopy, fluorescence lifetime imaging, diffuse optical tomography). Many of these applications are calling for new requests on the development of instrumentation that operates at higher and higher conversion rates and that is able to resolve optical signals not only in the time domain, but also in wavelength, polarization and position. To exploit the potential of parallel analysis over multiple acquisition channels, a new generation of TCSPC devices is needed that is characterized by low size and costs. The core block of TCSPC instrumentation is the time-interval measurement section, which can be implemented with a Time-to-Amplitude Converter (TAC); the converter can be integrated on a single chip in order to reduce the overall size and cost of the system. This paper presents a monolithic TAC that has been designed to achieve the high resolution, good differential linearity and fast counting rate required in modern applications. The TAC here described is built on a commercial 0.35 μm CMOS technology, and is characterized by resolution better than 60 ps, differential nonlinearity limited to 0.5% rms and short dead-time of 80 ns. The low area occupation (1.4x1.8 mm) and minimal need for external components allow the realization of very compact instruments with multiple acquisition channels operating simultaneously at very high count rates
2-Iodo-imidazolium receptor binds oxoanions via charge-assisted halogen bonding.
No full textA detailed (1)H-NMR study of the anion binding properties of the 2-iodo-imidazolium receptor 1 in DMSO allows to fully attribute the observed affinities to strong charge-assisted C-IX(-) halogen bonding (XB). Stronger binding was observed for oxoanions over halides. Phosphate, in particular, binds to 1 with an association constant of ca. 10(3) M(-1), which is particularly high for a single X-bond. A remarkably short C-IO(-) contact is observed in the structure of the salt 1·H(2)PO(4)(-)
Systematic Study of Podand Molecules for Synergistic Halogen and Hydrogen Bond-Driven Anion Recognition in the Solid State
No full textThe increasing demand of species for the efficient capture and sensing of anions benefits from a systematic study of anion binding capabilities in the solid state. This work reports a detailed crystallographic study of ten structurally related podands and shows that these charged receptors bind anions with a combination of charge-assisted halogen and hydrogen bonds. Computational tools helped in highlighting the role of the different involved interaction and afforded possible design principles for the design of improved podands
Recuerdos de Massimo.
No full textEl presente ensayo recuerda la rica relación personal e intelectual entre Massimo Pavarini e Iñaki Rivera Beiras desde que el segundo conoció siendo muy joven a Pavarini. En ese sentido, el trabajo recuerda los inicios de su fecunda relación en la ciudad de Bologna cuando Iñaki Rivera acudía a presentar a Massimo Pavarini los desarrollos de lo que sería su tesis doctoral. Las contribuciones de Pavarini al proceso de aprendizaje de Rivera, en el terreno de una epistemología crítica en la penología contemporánea, son analizados como un homenaje a la memoria y a la obra del autor italiano, tras su fallecimiento en septiembre de 2015.This paper recalls the rich personal and intellectual relationship between Massimo Pavarini and Iñaki Rivera Beiras. In that sense , the work recalls the beginning of his fruitful relationship in the city of Bologna when Iñaki Rivera came to present Massimo Pavarini’ developments in what would be his PhD thesis. Pavarini contributions to the learning process of Rivera, on the ground of a critical epistemology in contemporary penology , are analyzed as a tribute to the memory and to the work of Italian author, after his death in September 2015 .El presente ensayo recuerda la rica relación personal e intelectual entre Massimo Pavarini e Iñaki Rivera Beiras desde que el segundo conoció siendo muy joven a Pavarini. En ese sentido, el trabajo recuerda los inicios de su fecunda relación en la ciudad de Bologna cuando Iñaki Rivera acudía a presentar a Massimo Pavarini los desarrollos de lo que sería su tesis doctoral. Las contribuciones de Pavarini al proceso de aprendizaje de Rivera, en el terreno de una epistemología crítica en la penología contemporánea, son analizados como un homenaje a la memoria y a la obra del autor italiano, tras su fallecimiento en septiembre de 2015
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