An ERP study of sensory mismatch expressions in Japanese

Combinations of different sensory words produce mismatch expressions like smooth color and red touch in contrast to normal expressions like red color and smooth touch. Concerning these sensory mismatch expressions, results of three experiments are reported. Experiment 1 revealed that (i) mismatch expressions were less comprehensible than normal expressions, and that (ii) there were two patterns among mismatch expressions: the high-comprehensible mismatch expression (HighCME, e.g., smooth color) and the low-comprehensible mismatch expression (LowCME, e.g., red touch). Experiment 2 revealed that the mismatch expressions produced a significantly greater N400 amplitude than the normal expressions. Experiment 3 implied that the difference between High/LowCME was reflected in a later latency band or in a topographical difference of N400, although the statistical significance was marginal. It is argued that the processes to integrate linguistic elements (e.g., combining adjectives and nouns) are not homogeneous.     

情绪面孔的意识神经相关物及其无意识自动加工：来自事件相关电位的证据

意识的神经相关物尚有争议, 且个体能否无意识自动检测视觉环境变化尚不清楚。本研究采用非注意视盲范式操控视觉意识, 并引入具有社会信息的情绪面孔, 探讨意识的神经相关物以及视觉意识与自动检测变化机制的关系。在A阶段, 部分被试对任务无关的情绪面孔处于无意识水平; 在B阶段, 所有被试对任务无关的情绪面孔处于意识水平; 在C阶段, 所有被试对任务相关的情绪面孔处于意识水平。结果显示, 任务无关的情绪面孔的意识过程诱发视觉意识负波(visual awareness negativity, VAN)、晚期正成分(late positivity, LP)和晚期枕区正成分(late occipital positivity, LOP)。此外, 无意识的情绪面孔能诱发视觉失匹配负波(visual mismatch negativity, vMMN), 且其幅值不受意识影响, 但是受任务相关性调制。这些结果提示对情绪面孔的视觉意识在不同的时间进程上有不同的ERP指标——VAN反映早期知觉经验, 而LP和LOP反映晚期意识过程, 而且面孔情绪信息的自动加工独立于视觉意识, 但是受视觉注意调制。     

Microwave-dielectric and magnetic properties of Ta-doped BiFeO3 nanopowders

BiFe_{1? x} Ta _x O₃ (x = 0, 0.05, 0.1) nanopowders have been fabricated by a simple sol–gel method. Dielectric measurements at microwave frequencies (2–18 GHz) were made using a vector network analyser. Without tantalum, the BiFeO₃ nanopowder presents a relaxation-like response with a characteristic frequency of 15 GHz, which can be associated with an overdamped process. The Ta-doped nanopowders, however, show resonant behaviour with resonant frequencies of 12.5 and 14.6 GHz. The intensity of the resonant peak near 14.6 GHz decreases with increasing Ta addition. This behaviour is associated with a damped resonance process. Room-temperature magnetic measurements indicate that the addition of Ta influences the magnetic properties of the BiFeO₃ nanopowders, with BiFe_0.95Ta_0.05O₃ having the strongest ferromagnetism with a saturation magnetisation M _s of about 0.05 µ_B/Fe. The origin of the enhanced ferromagnetism is possibly associated with the distortion of the oxygen octahedral by the Ta substitution or/and the statistical distribution of Fe³⁺ and Fe²⁺.     

Frequency-temperature dependent dynamics of dielectrics in ferric oxoborate Fe3BO6 of cocktail structure of nanorods

Oxoborates have both dielectric and magnetic properties useful for magnetodielectric devices, sensors, or biological tools. Such compounds Fe₂BO₄, Fe₃BO₅, or Fe₃BO₆ are known to grow easily as single crystals in a liquid flux. A polycrystalline phase forms only on controlled conditions of a solid state reaction of the basic oxides. In this study, we report highly dielectric Fe₃BO₆ when grown in a specific shape of nanorods (～200?nm diameter and 50–100?µm length) from an iron borate glass, which offers devisable shapes of sheets, discs, and fibers. Frequency (f)-temperature reliant dynamics of dielectric constant ε_r is studied over 25–300°C at 0.1–10^3?kHz frequencies. At low frequency such as 100?Hz, a large ε_r -value 40,000, better than most of high ε_r -value ferroelectrics, incurs at room temperature. At f?≥?50?kHz, although only an order of diminished ε_r -value lasts, it increases steadily with temperature, possibly due to increasing electrical conductivity in a specific resistor–capacitor network. Suppressed dielectric relaxation and spin-flops share a merely weak spin-reorientation transition near 160°C. A stable power loss ≤0.5 lasts at f?>?10?kHz useful for possible applications of magnetodielectric materials.     

/n/-/l/音位合并现象的神经机制：来自MMN的证据

采用ERP技术,比较音位合并者与非音位合并者辨别合并音位/n/-/l/的脑电和行为反应。结果发现,非音位合并者在注意前阶段展现了显著的MMN;而音位合并者没有展现MMN,但在晚期展现了一个显著的负波。行为实验发现,相比于音位合并者,非音位合并者在分辨/n/-/l/时正确率更高,反应时更短。这些结果表明：两组被试区分/n/-/l/的能力在早期自动加工阶段就已经有了显著的差异。方言经验可能降低了音位合并者在听觉感觉加工阶段检测合并音位差异的敏感度。     

Brain mechanisms associated with background monitoring of the environment for potentially significant sensory events

Background monitoring is a necessary prerequisite to detect unexpected changes in the environment, while being involved in a primary task. Here, we used fMRI to investigate the neural mechanisms that underlie adaptive goal-directed behavior in a cued task switching paradigm during real response conflict or, more generally, when expectations on the repetitive features of the environment were violated. Unexpected changes in sensory stimulus attributes in the currently unattended stimulus dimension thereby led to activations in a bilateral network comprising inferior lateral frontal, intraparietal, and posterior medial frontal brain regions, independent of whether these attributes elicited a factual response conflict or not. This fronto-parietal network may thus play an important role in adaptive responding to potentially significant events outside the current focus of attention.     

Assessing the Predictive Accuracy of hMLH1 and hMSH2 Mutation Probability Models

Hereditary nonpolyposis colorectal cancer (HNPCC) is characterized by a susceptibility to colorectal and extra-colonic cancers. Several guidelines exist for the identification of families suspected of having HNPCC, however these guidelines lack adequate sensitivity and specificity. In an attempt to improve accuracy for the detection of individuals with HNPCC, the Wijnen pre-test probability model (1998) and Myriad Genetics Laboratory prevalence table (2004) were developed. Here we evaluate the Wijnen model and Myriad table at predicting the presence of a mutation in individuals undergoing genetic testing for HNPCC. Forty-nine patients who had undergone genetic testing for germline mutations in hMLH1 and/or hMSH2 were part of our analysis. Our results revealed that the revised Bethesda guidelines performed with the highest sensitivity for germline mutations (94.4%), however the specificity was low (12.9%). Using a 10.0% mutation probability threshold, the Wijnen model and Myriad table had sensitivities of 55.6 and 60.0%, respectively and specificities of 54.8 and 23.8%, respectively. The Wijnen model and Myriad table were poor predictors of mutation prevalence, which is shown by the areas underneath their corresponding receiver operator characteristic curves (0.616 and 0.400, respectively). The results of this study demonsrate that neither the Wijnen model nor the Myriad table are sensitive or specific enough to be used as the only indication when to offer genetic testing for HNPCC.     

关于知觉干扰效应的ERP研究

利用ERP技术,采用知觉干扰效应的经典实验范式,首次从神经生理水平上探究知觉干扰效应的内部机制。结果发现,递进条件和标准条件均诱发了P2,P3,N400和晚期正成分LPC。在P2,P3和LPC成分上,标准条件的波幅均显著大于递进条件;在N400成分上,递进条件比标准条件波幅更负,潜伏期更长。此外,对递进条件下靶字各模糊水平（Level 1～Level 5）的ERPs进行比较分析表明,N400成分的波幅在各模糊水平间的差异均不显著。基本支持失匹配理论及词汇自动加工理论。     

老年患者主动脉瓣置换术后不匹配对患者远期生存影响的研究

研究老年患者主动脉瓣置换术（AVR）后生存情况,评估人工瓣膜-患者不匹配（PPM）对患者远期生存率的影响.回顾性分析了自2000年7月～2005年7月的100例65岁以上实施单纯性AVR或同时行冠状动脉旁路移植术患者的资料.临床随访时间定于术后1个月、6个月、1年、3年、5年、7年及以上,收集并分析主动脉瓣位平均跨瓣压差（MGP）、左室射血分数（LVEF）、实际生存率等数据,比较患者的远期生存情况.患者术后30天病死率两组间差异有统计学意义.长期生存率自第7年开始在两组间表现出显著差异,组内差异表现在重度不匹配组.老年患者AVR术后PPM与术后早期病死率密切相关,重度PPM似乎影响远期生存率.     

Dominant factors influencing the nanoindentation response of piezoelectric materials: a case study in relaxor ferroelectrics

The nanoindentation response of a piezoelectric material is, in general, influenced in a complex manner by its elastic, dielectric and piezoelectric properties. The present study is focused on obtaining a comprehensive understanding of the dominant material factors influencing the force–depth mechanical indentation response and the charge–depth electrical indentation response of piezoelectric materials. From a large number of three-dimensional finite element simulations of the indentation of simple and complex piezoelectric materials (such as PZT-5A and relaxor ferroelectrics), the following principal conclusions are obtained: (1) For indentations with both conducting and insulating indenters, the mechanical indentation stiffness is influenced more by the elastic properties, while the electrical indentation stiffness is influenced largely by the piezoelectric properties of the indented materials. (2) For longitudinal indentations using a conducting indenter, the elastic constants, C ₃₃ and C ₁₃, and piezoelectric constants, e₃₃ and e₁₅, are, respectively, the first and second most dominant material constants that influence the mechanical indentation stiffness and the electrical indentation stiffness. (3) For transverse indentations using a conducting indenter, the elastic constants, C ₁₁ and C ₁₂, are, respectively, the first and second most dominant material constants that influence the mechanical indentation stiffness. (4) In the indentation of relaxor ferroelectrics based on PMN-xPT and PZN-xPT, which exhibit a range of elastic, dielectric and piezoelectric properties, it is generally observed that materials with higher normal elastic and piezoelectric constants, i.e., C ₃₃ and e₃₃, respectively, exhibit higher mechanical and electrical indentation stiffnesses.