A pulsed neural network model of spectro-temporal receptive fields and population coding in auditory cortex

The existence of spectro-temporal receptive fields and evidence for population coding in auditory cortex motivate the development of such models, that explicitly operate in the time-frequency domain and are based on a pulsed neural network. In presenting such a model, a formal connection of the fields of Time Frequency Analysis and Pulsed Neural Networks is established. The resulting neural time-frequency signal representation is shown to be representable as a signal-dependent overcomplete dictionary. It is derived from neural population coding. Signal decomposition and filtering effects are presented, indicating obvious technical applications of the proposed model. This revised version was published online in June 2006 with corrections to the Cover Date.     

A portable functional imaging instrument for psychology research based on near-infrared spectroscopy

To aid psychology researches on the function of the prefrontal cortex, a 16-channel brain functional imaging instrument based on near-infrared spectroscopy is developed. The probe of the instrument, covering a detection area of 15 cm x 4.4 cm of the prefrontal cortex, is made flexible and is easy to fix to the forehead. By employing multi-wavelength LEDs as light sources, using integrated detectors and choosing a USB-interface-based data acquisition device, the whole system is portable and convenient to use, which is good for psychological experiments. The system software is developed using Visual C++ 6.0, which controls the imaging process, measurement data plotting and storage. The maximal temporal resolution is about 100 ms. Noise and long-term drift test are given. The Valsalva maneuver experiment is used to validate the reliability of the instrument for monitoring hemodynamic changes.     

不同加工方式对牡丹皮药材中丹皮酚含量的影响

目的考察不同加工方式对牡丹皮药材中丹皮酚含量的影响。方法采用RP-HPLC法,迪马C18色谱柱(250mm×4.6 mm,5μm);以甲醇-水(45∶55)为流动相,流速1.0 mL/min;检测波长274 nm。结果丹皮酚的线性范围为0.1330～0.3102μg,r=0.9999,平均加样回收率99.18%,RSD=0.80%。不同规格间丹皮酚含量差异较大。结论不同加工方式对牡丹皮药材中丹皮酚含量有较大影响。     

基于图割和水平集的肾脏医学图像分割

肾脏医学图像分割是医学图像分析和非侵入式计算机辅助诊断系统中的关键步骤。从CT、MRI图像中分割出肾脏及肾皮质,计算其体积和皮质厚度等信息,有助于评估肾脏的功能,从而制定相应的治疗方案。根据肾脏序列图像相邻切片之间结构灰度分布的相似性,提出了一种基于图割和水平集方法的自动肾脏及肾皮质分割方法。选取皮质区域具有足够对比度和清晰度的切片为初始参考图像,使用霍夫森林算法检测肾脏区域,对前景、背景进行均值聚类以估计其灰度分布,获取图割模型能量函数,分割出肾脏整体;通过形态学处理得到相邻切片肾脏的分割候选区域,重复上述分割。以此初步分割结果作为水平集方法的初始轮廓,进一步分割得到三维的肾脏整体和肾皮质区域。实验结果表明,基于图割和水平集的肾脏分割方法能够比较准确地分割出肾脏及肾皮质。     

正交设计法优化黄柏涂膜剂成膜材料的制备工艺

采用L9(33)正交实验,以涂膜剂外观性状及成膜时间为考核指标,对黄柏涂膜剂成膜材料的制备工艺进行了优化.结果表明,在10％ PVA-124用量为10 mL、10％ PVA-1788用量为10 mL、甘油用量为1.5 mL的条件下得到的成膜材料成膜性好、易于涂展、韧性强,黄柏提取物在其中溶解均匀.     

Does the Neuroprotective Role of Anandamide Display Diurnal Variations?

The endocannabinoid system is a component of the neuroprotective mechanisms that an organism displays after traumatic brain injury (TBI). A diurnal variation in several components of this system has been reported. This variation may influence the recovery and survival rate after TBI. We have previously reported that the recovery and survival rate of rats is higher if TBI occurs at 1:00 than at 13:00. This could be explained by a diurnal variation of the endocannabinoid system. Here, we describe the effects of anandamide administration in rats prior to the induction of TBI at two different times of the day: 1:00 and 13:00. We found that anandamide reduced the neurological damage at both times. Nevertheless, its effects on bleeding, survival, food intake, and body weight were dependent on the time of TBI. In addition, we analyzed the diurnal variation of the expression of the cannabinoid receptors CB1R and CB2R in the cerebral cortex of both control rats and rats subjected to TBI. We found that CB1R protein was expressed more during the day, whereas its mRNA level was higher during the night. We did not find a diurnal variation for the CB2R. In addition, we also found that TBI increased CB1R and CB2R in the contralateral hemisphere and disrupted the CB1R diurnal cycle.