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701.
Camacho CM Camsonne A Mazouz M Ferdi C Gavalian G Kuchina E Amarian M Aniol KA Beaumel M Benaoum H Bertin P Brossard M Chen JP Chudakov E Craver B Cusanno F de Jager CW Deur A Feuerbach R Fieschi JM Frullani S Garçon M Garibaldi F Gayou O Gilman R Gomez J Gueye P Guichon PA Guillon B Hansen O Hayes D Higinbotham D Holmstrom T Hyde-Wright CE Ibrahim H Igarashi R Jiang X Jo HS Kaufman LJ Kelleher A Kolarkar A Kumbartzki G Laveissière G Lerose JJ Lindgren R Liyanage N Lu HJ Margaziotis DJ 《Physical review letters》2006,97(26):262002
We present the first measurements of the e[over -->]p-->epgamma cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region. The Q(2) dependence (from 1.5 to 2.3 GeV(2)) of the helicity-dependent cross section indicates the twist-2 dominance of DVCS, proving that generalized parton distributions (GPDs) are accessible to experiment at moderate Q(2). The helicity-independent cross section is also measured at Q(2)=2.3 GeV(2). We present the first model-independent measurement of linear combinations of GPDs and GPD integrals up to the twist-3 approximation. 相似文献
702.
Attila Gáspár István Bácsi Erika F. Garcia Mihály Braun Frank A. Gomez 《Analytical and bioanalytical chemistry》2009,395(2):473-478
The goal of this work was to increase the sensitivity of a UV–Vis spectrophotometer by decreasing the background noise and
lengthening the optical path. A microphotometer has been modified to precisely select very small parts of a microfluidic channel
pattern of a chip and to measure light absorbance on a magnified area of the selected part of the channel. The viability of
combining a projection microscope and a spectrophotometer for external absorbance measurements on disposable PDMS chips was
studied. Besides the external direct detection above a microfluidic channel, the optical pathlength was lengthened by detecting
in the region of the perpendicular exit port. Increasing the cross-sectional area of the zone of irradiation improved the
signal-to-noise ratio and the limits of detection (LOD). 相似文献
703.
In the neighborhood of critical states, distinct materials exhibit the same physical behavior, expressed by common simple laws among measurable observables, hence rendering a more detailed analysis of the individual systems obsolete. It is a widespread view that critical states are fundamental to neuroscience and directly favor computation. We argue here that from an evolutionary point of view, critical points seem indeed to be a natural phenomenon. Using mammalian hearing as our example, we show, however, explicitly that criticality does not describe the proper computational process and thus is only indirectly related to the computation in neural systems. 相似文献
704.
Christian A. Gomez Dibyendu Mondal Qian Du Natalie Chan Jared C. Lewis 《Angewandte Chemie (International ed. in English)》2023,62(15):e202301370
FeII- and α-ketoglutarate-dependent halogenases and oxygenases can catalyze site-selective functionalization of C−H bonds via a variety of C−X bond forming reactions, but achieving high chemoselectivity for functionalization using non-native functional groups remains rare. The current study shows that directed evolution can be used to engineer variants of the dioxygenase SadX that address this challenge. Site-selective azidation of succinylated amino acids and a succinylated amine was achieved as a result of mutations throughout the SadX structure. The installed azide group was reduced to a primary amine, and the succinyl group required for azidation was enzymatically cleaved to provide the corresponding amine. These results provide a promising starting point for evolving additional SadX variants with activity on structurally distinct substrates and for enabling enzymatic C−H functionalization with other non-native functional groups. 相似文献
705.
706.
Shu Hui Wang Luiziana F. Silva Juliana Kloss Marilda Munaro Gabriel Pinto de Souza M. Alice Wada J. Gregório C. Gomez S. Zawadzki L. Akcelrud 《Macromolecular Symposia》2003,197(1):255-264
Two series of segmented polyurethanes were prepared with systematic variation in soft and hard segment length. The soft segment was constituted by polycaprolactone (PCL) blocks of molecular masses 530 or 2000 and the hard segment (HS) by urethane blocks, in a concentration that varied from 12% to 44% in weight of the whole polyurethane. Morphological analyses indicated that the amount of crystallinity of copolymers was strongly dependent on the PCL molar mass and hard segment content. The copolymers with longer PCL soft segments (Mn=2000) were semicrystalline, but those with shorter PCL segment (Mn=530) were unable to crystallize. The primary factor affectingthe biodegradability of copolymers as evaluated by Sturm tests was the extent of the phase separation, and that the segmental blending of the less biodegradable polyurethane (HS) blocks with PCL in the amorphous phase had a critical unfavorable consequence, which may be attributed to the size of the accessible area by microorganisms. 相似文献
707.