To investigate the features of electroencephalography （EEG） power and coherence at rest and during a working memory task of patients with mild cognitive impairment （MCI）. Thirty-five patients （17 males, 18 female...To investigate the features of electroencephalography （EEG） power and coherence at rest and during a working memory task of patients with mild cognitive impairment （MCI）. Thirty-five patients （17 males, 18 females; 52-71 years old） and 34 sex- and age-matched controls （17 males, 17 females; 51-63 years old） were recruited in the present study. Mini-Mental State Examination （MMSE） of 35 patients with MCI and 34 normal controls revealed that the scores of MCI patients did not differ significantly from those of normal controls （P〉0.05）. Then, EEGs at rest and during working memory task with three levels of working memory load were recorded. The EEG power was computed over 10 channels： fight and left frontal （F3, F4）, central （C3, C4）, parietal （P3, P4）, temporal （T5, T6） and occipital （O1, O2）; inter-hemispheric coherences were computed from five electrode pairs of F3-F4, C3-C4, P3-P4, T5-T6 and O1-O2 for delta （1.0-3.5 Hz）, theta （4.0-7.5 Hz）, alpha-1 （8.0-10.0 Hz）, alpha-2 （10.5-13.0 Hz）, beta-1 （13.5-18.0 Hz） and beta-2 （18.5-30.0 Hz） frequency bands. All values of the EEG power of MCI patients were found to be higher than those of normal controls at rest and during working memory tasks. Furthermore, the values of EEG power in the theta, alpha-1, alpha-2 and beta-1 bands of patients with MCI were significantly high （P〈0.05） in comparison with those of normal controls. Correlation analysis indicated a significant negative correlation between the EEG powers and MMSE scores. In addition, during working memory tasks, the EEG coherences in all bands were significantly higher in the MCI group in comparison with those in the control group （P〈0.05）. However, there was no significant difference in EEG coherences between two groups at rest. These findings comprise evidence that MCI patients have higher EEG power at rest, and higher EEG power and coherence during working conditions. It suggests that MCI may be associated with compensatory processes at rest and during working memory tasks. Moreover, failure of normal cortical connections may be exist in MCI patients.展开更多
A design for a fisheye optical system is modified in order to enable IR vision in addition to the visible and UV lighting. The proposed modification goes to replace the optical material of the movable lens by another ...A design for a fisheye optical system is modified in order to enable IR vision in addition to the visible and UV lighting. The proposed modification goes to replace the optical material of the movable lens by another with less thermal dispersion. The choice of appropriate materials lead to a good focus appeared on the retina for a wide spectral range includes UV, visible, and near IR lighting. Then, the performance of the modified design is verified through some optical measures for imaging quality determinations. These optical measures are determined with the aid of Zemax software, which also used for testing performance of the modified fisheye optical system. The analysis mainly focuses on the energy distribution in the light spot on the focal surface. The results show that the modified design of the fisheye is acceptable.展开更多
文摘通过对静态随机存取存储器(static random-access memory,SRAM)单粒子翻转截面的研究,提出了一种更有效、成本更低、可测量一到几十兆电子伏能量范围内中子能谱的新方法。利用已发表单粒子翻转截面信息的SRAM,采用奇异值分解(singular value decomposition,SVD)方法进行解谱,可测试低能中子源的中子能谱。在进一步的研究中,利用信息熵理论研究了SRAM的数量与能谱测试准确性的关系。研究结果表明,解谱结果的精度在很大程度上取决于SRAM翻转截面的敏感区宽度和参与解谱的不同SRAM的数量。
文摘To investigate the features of electroencephalography （EEG） power and coherence at rest and during a working memory task of patients with mild cognitive impairment （MCI）. Thirty-five patients （17 males, 18 females; 52-71 years old） and 34 sex- and age-matched controls （17 males, 17 females; 51-63 years old） were recruited in the present study. Mini-Mental State Examination （MMSE） of 35 patients with MCI and 34 normal controls revealed that the scores of MCI patients did not differ significantly from those of normal controls （P〉0.05）. Then, EEGs at rest and during working memory task with three levels of working memory load were recorded. The EEG power was computed over 10 channels： fight and left frontal （F3, F4）, central （C3, C4）, parietal （P3, P4）, temporal （T5, T6） and occipital （O1, O2）; inter-hemispheric coherences were computed from five electrode pairs of F3-F4, C3-C4, P3-P4, T5-T6 and O1-O2 for delta （1.0-3.5 Hz）, theta （4.0-7.5 Hz）, alpha-1 （8.0-10.0 Hz）, alpha-2 （10.5-13.0 Hz）, beta-1 （13.5-18.0 Hz） and beta-2 （18.5-30.0 Hz） frequency bands. All values of the EEG power of MCI patients were found to be higher than those of normal controls at rest and during working memory tasks. Furthermore, the values of EEG power in the theta, alpha-1, alpha-2 and beta-1 bands of patients with MCI were significantly high （P〈0.05） in comparison with those of normal controls. Correlation analysis indicated a significant negative correlation between the EEG powers and MMSE scores. In addition, during working memory tasks, the EEG coherences in all bands were significantly higher in the MCI group in comparison with those in the control group （P〈0.05）. However, there was no significant difference in EEG coherences between two groups at rest. These findings comprise evidence that MCI patients have higher EEG power at rest, and higher EEG power and coherence during working conditions. It suggests that MCI may be associated with compensatory processes at rest and during working memory tasks. Moreover, failure of normal cortical connections may be exist in MCI patients.
文摘A design for a fisheye optical system is modified in order to enable IR vision in addition to the visible and UV lighting. The proposed modification goes to replace the optical material of the movable lens by another with less thermal dispersion. The choice of appropriate materials lead to a good focus appeared on the retina for a wide spectral range includes UV, visible, and near IR lighting. Then, the performance of the modified design is verified through some optical measures for imaging quality determinations. These optical measures are determined with the aid of Zemax software, which also used for testing performance of the modified fisheye optical system. The analysis mainly focuses on the energy distribution in the light spot on the focal surface. The results show that the modified design of the fisheye is acceptable.
