噪声中EP信号的提取算法及研究进展

诱发电位的提取是脑电信号处理领域的前沿课题近年来 ,通过少次甚至单次试验提取诱发电位已经成为研究的主流。本文对近年来提取诱发电位的信号处理方法进行了简要的回顾 ,并分别从小波变换、神经网络、高阶累积量、独立分量分析等四个方面对算法进行了介绍     

结缔组织生长因子在脑胶质瘤组织中的表达和肿瘤级别的关系

目的通过检测人脑胶质瘤患者肿瘤组织中结缔组织生长因子的表达水平,探讨其和肿瘤级别的关系及作用机制。方法采用荧光实时定量聚合酶链式反应(RT-PCR)法检测结缔组织生长因子(CTGF)mRNA在47例脑胶质瘤组织和25例正常脑组织中的表达水平,统计分析表达水平和肿瘤级别之间的关系。结果CTGF在胶质瘤Ⅰ-Ⅱ级(高分化组)及胶质瘤Ⅲ~Ⅳ级(低分化组)中的表达均明显高于正常脑组织(P<0.01),而且在Ⅲ~Ⅳ级胶质瘤中的表达量显著高于胶质瘤Ⅰ~Ⅱ级(P<0.01),说明随着肿瘤级别的升高CTGF表达也增强。结论CTGF在胶质瘤组织中高表达,而且表达水平和恶性程度有密切联系。CTGF的检测可作为胶质瘤恶性程度判断的参考,为从基因水平上探讨胶质瘤的生物学行为、预后及治疗提供新的思路。     

Functional differences among those high and low on a trait measure of psychopathy.

BACKGROUND: It has been established that individuals who score high on measures of psychopathy demonstrate difficulty when performing tasks requiring the interpretation of other's emotional states. The aim of this study was to elucidate the relation of emotion and cognition to individual differences on a standard psychopathy personality inventory (PPI) among a nonpsychiatric population. METHODS: Twenty participants completed the PPI. Following survey completion, a mean split of their scores on the emotional-interpersonal factor was performed, and participants were placed into a high or low group. Functional magnetic resonance imaging data were collected while participants performed a recognition task that required attention be given to either the affect or identity of target stimuli. RESULTS: No significant behavioral differences were found. In response to the affect recognition task, significant differences between high- and low-scoring subjects were observed in several subregions of the frontal cortex, as well as the amygdala. No significant differences were found between the groups in response to the identity recognition condition. CONCLUSIONS: Results indicate that participants scoring high on the PPI, although not behaviorally distinct, demonstrate a significantly different pattern of neural activity (as measured by blood oxygen level-dependent contrast)in response to tasks that require affective processing. The results suggest a unique neural signature associated with personality differences in a nonpsychiatric population.     

Effects of weight loss in overweight/obese individuals and long-term lipid outcomes – a systematic review

This paper aims to review the evidence for long‐term effectiveness of weight loss on cholesterol, high‐density lipoprotein (HDL), low‐density lipoprotein (LDL) and triglycerides in overweight/obese people. Current evidence is mostly based on short‐term studies. A systematic review of long‐term lipid outcomes of weight loss in studies published between 1966 and 2001, was conducted. Inclusion criteria included all cohort studies and trials carried out on participants with body mass index of greater than or equal to 28 kg m^?2. Studies had at least two weight change measurements and follow‐up of more than 2 years. Thirteen long‐term studies with a follow‐up of more than 2 years were included. Cholesterol has a significant positive linear relationship with weight change (r = 0.89) where change in weight explains about 80% of the cholesterol difference variation (Adj R² = 0.80). For every 10 kg weight loss a drop of 0.23 mmol L^?1 in cholesterol may be expected for a person suffering from obesity or are grossly overweight. Weight loss has long‐term beneficial effects especially on LDL and cholesterol. Weight loss in obese patients should be encouraged and sustained.     

抗抑郁剂对慢性应激抑郁大鼠脑内5-HT1A受体和5-HT2A受体的影响

目的 以慢性不可预见性应激抑郁模型为基础,探讨三环类抗抑郁剂 (TCAs)和 5 羟色胺再摄取抑制剂(SSRI)在 5 羟色胺受体水平的药理学机理。方法 将 24只SD雄性大鼠随机分对照组、抑郁模型组、阿米替林治疗组、氟西汀治疗组。应用 [3H]8 OH DPAT、[3H]Ketanserin作为标记配基,采用放射性配体受体结合法,分别测定大鼠海马 5 HT1A受体、大脑皮层 5 HT2A受体的特异性结合。结果 与正常对照组比较,抑郁大鼠海马 [3H] 8 OH DPAT特异性结合明显下降 ( 18. 78±5. 62vs26. 12±5. 52, P<0. 05),抑郁大鼠大脑皮层[3H]Ketanserin特异性结合显著增加(86. 28±4. 24vs112. 58±4. 21,P<0. 05)。阿米替林治疗 3周后,抑郁大鼠海马 [3H] 8 OH DPAT特异性结合回升到正常水平,大脑皮层 [3H]Ketan serin特异性结合下降至正常水平(P<0. 05)。氟西汀治疗 3周后,抑郁大鼠海马 [3H]8 OH DPAT特异性结合(26. 63±5. 50)、大脑皮层[3H]Ketanserin特异性结合 (83. 16±2. 54)与抑郁组比较差异无显著性 (P>0. 05)。结论 1.阿米替林通过增强海马 5 HT1A受体功能、抑制大脑皮层 5 HT2A受体功能发挥抗抑郁作用。2.氟西汀可能不通过影响海马 5 HT1A受体和大脑皮层 5 HT2A受体功能发挥抗抑郁作用。     

微波辅助提取茯苓中茯苓多糖的研究

目的将微波辅助提取新技术应用于茯苓水溶性多糖的提取，寻求最佳提取工艺。方法采用均匀优化设计试验条件，以苯酚-硫酸法测定样品中多糖含量。对超声辅助提取和传统水提法比较，并对水解前后的微波提取多糖衍生物用毛细管电泳检测。结果最佳提取条件：时间为18min；固液比为1：50；微波占空比42％，此时提取率为2．792％。优于传统。结论微波辅助提取速度更快、提取效率更高；毛细管电泳检测表明微波提取茯苓多糖过程合理，能得到较理想的提取物。     

Off-resonance effects in the transient response of SSFP sequences.

A previously developed eigenvector formalism is adapted to off-resonance in the transient response of quasiperiodic steady-state free precession (SSFP) sequences, including TrueFISP as a special case. The effective relaxation rates for essentially parallel and perpendicular deviations from the steady state are determined analytically in leading order perturbation theory. The latter are a known cause of oscillatory artifacts and therefore constitute the main target of a variety of preparation techniques. In addition, the former also play a dominating role in applications such as inversion recovery (IR) TrueFISP, which intentionally measure far away from the equilibrium. For both components, the approach toward equilibrium turns out to depend sensitively on field inhomogeneities, especially for smaller ratios of T2/T1. For the perpendicular deviations, the calculations show that--except very close to banding artifacts, where the steady-state signal is almost zero--field inhomogeneities additionally increase their effective relaxation rate almost as much as in the free induction decay (FID). The analytical results are tested against numerical simulation and MR measurements.     

View ordering for magnetization prepared steady state free precession acquisition: application in contrast-enhanced MR angiography.

Magnetization prepared segmented acquisition requires a view order that maximizes signal contrast during the acquisition of the central portion of k-space. Steady state free precession (SSFP) acquisition further requires a view order that minimizes changes in phase-encoding gradients from one repetition to the next in order to minimize eddy current artifacts. In this article, optimal view ordering schemes satisfying these two requirements are formulated and applied to inversion prepared 3D SSFP contrast-enhanced MR angiography (MRA). Experiments on phantoms and pigs demonstrated improved background suppression and reduced image artifacts.     

骺板软骨细胞复合三维支架体外构建组织工程软骨的研究

目的探讨将骺板软骨细胞复合三维支架经体外培养,构建组织工程软骨的效果及其生物学特点. 方法将3周龄幼兔第1代骺板软骨细胞与液态的生物凝胶混合,接种于聚磷酸钙纤维/L-聚乳酸(CPPF/PLLA)三维支架材料,构建组织工程软骨组织块,连续培养4周.行大体、倒置显微镜及组织学、Ⅰ型和Ⅱ型胶原免疫组织化学光镜观察,定量检测硫酸糖胺多糖(GAG)含量. 结果构建的组织工程软骨块在培养过程中能保持其初始外形,种子细胞呈稳定的三维均相分布,外观逐渐呈乳白色、半透明,硬度亦不断增加.培养1周有软骨细胞陷窝形成,2周后形成富含Ⅱ型胶原和蛋白聚糖、具有典型软骨组织结构的工程化软骨,且Ⅰ型胶原逐渐转为阴性.4周时构建软骨的组织结构与天然骺板软骨相类似,硫酸GAG含量平均为天然骺板软骨的34%以上. 结论骺板软骨细胞复合三维支架体外培养可生成典型软骨,且可形成类似天然骺板软骨的组织结构,能满足修复骺板缺损的基本要求.体外培养1～2周可能是植入体内修复骺板缺损的较佳时机.