科研成果 by Year: 2016

The photophysics of a series of bichromophoric molecules featuring an intramolecular triplet energy transfer between a triscyclometalated iridium(III) complex and covalently linked organic group are studied. By systematically varying the energy gap (0.1-0.3 eV) between the donor (metal complex) and acceptor (pyrene unit), reversible triplet energy transfer processes with equilibrium constant K ranging from ca. 500 to 40 000 are established. Unique photophysical consequences of such large K values are observed. Because of the highly imbalanced forward and backward energy transfer rates, triplet excitons dominantly populate the acceptor moiety in the steady state, giving rise to ultralong luminescence lifetimes up to 1-4 ms. Because the triscyclometalated Ir and triplet pyrene groups both impart relatively small nonradiative energy loss, decent phosphorescence quantum yields (Phi = 0.1-0.6) are attained in spite of the exceptionally prolonged excited states. By virtue of such precious combination of long-lived triplet state and high Phi, these bichromophoric molecules can serve as highly sensitive luminescent sensors for detecting trace amount of O-2 and as potent photosensitizers for producing singlet oxygen even under low-oxygen content conditions.

Eight PBDE congeners, BDE-28, 47, 99, 100, 153, 154, 183 and 209, were measured using gas chromatography coupled to mass spectrometry. The concentrations of Σ8PBDEs ranged from 0.04 to 19.93 ng g−1 lipid weight (lw), with median and mean value of 1.21 and 2.72 ng g−1 lw. PBDE congeners were detected in approximately 90 % of samples with BDE-209 as the dominant one. No significant correlations were found between the mothers’ age, body mass index and PBDEs concentrations. We estimated the infant’s dietary intake of the studied PBDEs via human milk during different nursing durations, and found that babies younger than 1 month might take a relatively higher body burden of PBDEs. The median levels of Σ8PBDEs were 0.74, 2.80, 2.43 and 0.90 ng g−1 lw in colostrum, milk sampled at 1, 3 and 6 months after birth, respectively. High consumption of animal-origin food after birth may lead to the elevated ΣPBDEs concentrations in breast milk. A rational nutrition deployment is essential for postpartum mother.

This chapter proposes to read the sculptural program of the Philopappos Monument at Athens from the perspective of power and status of the Orontid’s royal house of the kingdom of Commagene. Investigations will focus on the honorand’s grandfather, Antiochus IV of Commagene, styled as a togate figure and sitting on a sella curule, and how such choice can interpret Philopappus’ career. This chapter argues that the monumental façade of the Commagenian king Philopappus defines the concept of client-kingship as a non-territorial Roman institution. Client-kings and their members were a class of their own within the Roman political hierarchy, and served bureaucratic functions.

Practice improves discrimination of many basic visual features, such as contrast, orientation, and positional offset [1-7]. Perceptual learning of many of these tasks is found to be retinal location specific, in that learning transfers little to an untrained retinal location [1, 6-8]. In most perceptual learning models, this location specificity is interpreted as a pointer to a retinotopic early visual cortical locus of learning [1, 6-11]. Alternatively, an untested hypothesis is that learning could occur in a central site, but it consists of two separate aspects: learning to discriminate a specific stimulus feature ("feature learning"), and learning to deal with stimulus-nonspecific factors like local noise at the stimulus location ("location learning") [12]. Therefore, learning is not transferable to a new location that has never been location trained. To test this hypothesis, we developed a novel double-training paradigm that employed conventional feature training (e.g., contrast) at one location, and additional training with an irrelevant feature/task (e.g., orientation) at a second location, either simultaneously or at a different time. Our results showed that this additional location training enabled a complete transfer of feature learning (e.g., contrast) to the second location. This finding challenges location specificity and its inferred cortical retinotopy as central concepts to many perceptual-learning models and suggests that perceptual learning involves higher nonretinotopic brain areas that enable location transfer.