内皮祖细胞治疗对经皮冠脉支架植入术后再内皮化研究进展

药物洗脱支架的使用很大程度上防止了支架内再狭窄,但随着其在临床上的广泛应用,晚期支架内血栓形成引起了人们的重视,这一并发症在一定程度上与再内皮化延迟有关.近年来对内皮祖细胞生物学特性的深入研究,使支架植入后快速再内皮化成为可能,从而为有效防止晚期支架内血栓形成提供了一个很好的研究方向.本文就此方面的研究进展作一综述.     

妊娠期睡眠障碍研究进展

妊娠期睡眠障碍指在妊娠期发生的睡眠形态和行为的紊乱,它已经成为影响孕妇生理、心理等问题的重要危险因素.本文主要从妊娠期睡眠障碍的概念、发生率、引起妊娠期睡眠障碍的原因、睡眠障碍对母亲、胎儿和妊娠结局的影响及睡眠障碍的干预措施等几个方面进行了综述.     

Voluntary triggering of the first target attenuates the attentional blink

The term attentional blink (AB) refers to a failure in identifying the second of two targets, separated by less than 500?ms, embedded in a rapid succession of nontargets. To examine whether the expectation of the onset of the first target affects the AB, we compared the magnitudes of the AB deficit when participants triggered the appearance of the first target and when the target was presented automatically at some time point, as in traditional AB studies. In Experiment 1, the first target appeared immediately after a participant's voluntary keypress, revealing that the accuracy for identifying the first target increased and that the AB deficit was attenuated. In Experiment 2, the temporal delay between a voluntary keypress and the first-target presentation was manipulated. The results showed that both targets could be reported accurately only when the first target was presented within 300?ms after the action. In Experiment 3, we ruled out an alternative explanation that would attribute the facilitation effect to mere physical movement, by examining the accuracy of target identification when participants voluntarily pressed a key but that action was unrelated to the onset of the first target. Taken together, the results suggest that voluntary action to trigger the onset of a visual target facilitates processing and reduces the subsequent AB deficit when the target appears within 300?ms of the action.     

Microstructure and mechanical behavior of nanostructured composite Cu60Fe40 alloy

In this study, bulk nanostructured composite Cu₆₀Fe₄₀ alloy is prepared by a combustion synthesis technique. The prepared Cu₆₀Fe₄₀ alloy consists of Cu(Fe) solid solution and Fe(Cu) solid solution phases. The large-scaled compositional segregation in the Cu-rich and Fe-rich phases is not observed, respectively. A few micron-sized dendrite (Fe(Cu) solid solution) is embedded into the nanostructured matrix (Cu(Fe) solid solution). The grain size of the matrix is in the range 50–300?nm. The yield and fracture strength of the Cu₆₀Fe₄₀ alloy are 540 and 1050?MPa, respectively, and the fracture strain obtained from the compression test is about 20.9%. The Cu₆₀Fe₄₀ alloy displays notable work hardening in the compressive deformation.     

Effects of Si addition on the microstructure evolution of Al–Cu–Mg alloys in the α + S + T phase field

The precipitation behaviour and age-hardening response of Al–1.5Cu–4.0Mg (wt.%) alloys microalloyed with Si have been investigated by means of hardness measurement, TEM and HRTEM. Compared to the ternary alloy, the quaternary alloys exhibit a higher hardness. It is found that the underaged microstructure in the Al–1.5Cu–4.0?Mg alloy contains some fine precipitates, which are identified as the T phase by FFT spectra. The peak-aged microstructures of the ternary alloy is dominated by the T phase, while the peak-aged microstructures of the Si-containing alloys are dominated by the S phase. The volume fraction of the S phase is found to increase as more Si is added.     

Molecular dynamics simulations of the size effect of titanium single-crystal nanopillars orientated for double prismatic slips

An inverse “smaller is stronger” trend is predicted on the basis of molecular dynamics simulations of α-titanium (Ti) single-crystal nanopillars orientated for double prismatic slips when the nanopillars are less than 7?nm wide. This trend is attributed to a significant increase in the surface energy due to the nucleation and propagation of edge dislocations on the surface of the pillars.     

Dysfunction of attentional networks for non-emotional processing in negative affect

It is unclear whether negative affect is associated with the impairment of attentional networks for non-emotional processing. Using the attention network test (ANT), which assesses the efficiency of alerting, orienting, and executive attention, we attempted to clarify which attentional networks were related to negative affect, i.e., anxiety, depression, and social anxiety. Forty-three participants completed the self-report questionnaires and the ANT. Negative affect was negatively correlated with orienting efficiency but not executive attention. Our results indicate that people with negative emotionality have an impaired orienting network for non-emotional stimuli. It is suggested that attentional bias for threatening stimuli in negative affect is due to the original impairment of the orienting network.     

Exogenous attention to angry faces in social anxiety: A perceptual accuracy approach

We investigated the interaction between endogenous and exogenous attention for the processing of emotional stimuli in individuals with high social anxiety using accuracy rates. Following the presentation of an endogenous cue at the centre, exogenous cues (i.e., angry and neutral faces) were presented at peripheral locations. Subsequently, non-emotional masked targets were presented, and the participants were instructed to discriminate between the targets. With respect to exogenous attention, high socially anxious people exhibited higher accuracy when the angry face and target appeared on the same side than when they appeared on different sides, whereas low socially anxious people did not exhibit such effects. On the other hand, different abilities of endogenous attention were not observed between high and low socially anxious people. These results suggest that exogenous attention is biased towards threat in high socially anxious people.     

Effects of response–stimulus interval manipulation and articulatory suppression on task switching

We conducted three experiments using a list paradigm to examine how articulatory suppression and response–stimulus interval (RSI) manipulation affected task switching. Experiments 1 and 2 tested task-switching performance under a short and long RSI and three concurrent task conditions (control, articulatory suppression, and tapping) without external task cues. The results indicated that alternation had a greater effect under articulatory suppression than under the control and tapping conditions, and that articulatory suppression costs were unrelated to the RSI. In Experiment 3, an external task cue was provided with each stimulus, and the negative effect of articulatory suppression on alternation cost was eliminated. These results indicated that articulatory suppression effects did not differ between conditions of short and long RSI and that the availability of verbal representations of task information was independent of RSI length. This paper discussed the possible roles played by the phonological loop in task-switching paradigms.     

Constraint on the semantic flexibility in visual statistical learning

We examined whether the expression of visual statistical learning (VSL) is flexible at the superordinate-categorical level. In the familiarization phase, participants viewed a sequence of line drawings. In the test phase, participants observed two test sequences (statistically related triplets versus unrelated foils) that consisted of the same objects as those presented during the familiarization phase (the same condition) or different objects that shared the same categorical information with drawings during the familiarization (the different condition). They then decided whether the first or the second sequence was more familiar. The results of Experiment 1 showed greater familiarity above chance levels for statistically related triplets only in the same condition. In Experiment 2, even where the word stimuli representing each superordinate-level category were included in the test phase (the categorical condition), the results showed VSL only in the same condition. Our findings suggest that the semantic flexibility of VSL is limited to the basic-level category.