基于小波变换的事件相关电位少次提取方法

本文以反映大脑稀少认知事件的相关电位P300为例,介绍了基于小波变换(wavelet transform,WT)进行事件相关电位(event related potential,ERP)少次提取的原理、仿真和实验结果.通过小波变换先去除与ERP混杂的EEG背景干扰,然后对消除干扰后的脑电数据进行重构和ERP波峰检测,在此基础上尝试修正ERP波峰的潜伏期时移,再通过小波重构获得通常需多次相干平均才能得到的ERP波形.仿真计算和实验数据分析结果说明小波分析具有较强的ERP峰值检测和潜伏期模式识别能力,值得进一步在临床工程中深入研究和应用推广.     

基于小波变换的闪光视觉诱发电位的有效提取及颅内压无创监测的实现

由于闪光视觉诱发电位(FVEP)的信号非常微弱,常常淹没在自发脑电(EEG)等强噪声中,必须采取有效的降噪方法才能正确提取到FVEP波形。本文根据FVEP的频率特征,利用平均叠加方法与多分辨率小波变换结合,有效地去除了自发EEG噪声信号,有效提取了FVEP波形,通过提取的FVEP波形中的N2波对应的波峰潜伏期与颅内压(ICP)之间的相关关系,从而实现了ICP的无创检测。     

阿尔茨海默病、血管性痴呆、帕金森病痴呆病人听觉认知电位的比较研究

目的 :探讨听觉事件相关电位 (ERP)在阿尔茨海默病 (AD)、血管性痴呆 (VD)、帕金森病痴呆 (PDD)中的差异及意义。方法 :应用ERP检测方法对 2 4例AD患者、2 2例VD患者、16例PDD患者及 30位正常人进行对照研究。结果 :①ERP的内源成分 :P30 0电位 (即P3波 )三组间异常程度不同 ,呈梯度变化。VD组P3潜伏期最长 ,AD组次之 ,PDD组再次之 (均P <0 .0 5 ) ;②ERP的外源成分 :三组N1波改变各异 ,VD组潜伏期延长 ,波幅降低 ;AD组仅波幅降低 ;PDD组正常 ;③峰间期 :AD、VD两组P2—N2、N2—P3、N1—P3峰间期延长 ,PDD组各波峰间期正常。结论 :AD、VD及PDD三种疾病听觉ERP异常程度及异常成分存在差异 ,上述电生理特征对区分痴呆类型具有一定价值。     

基于小波和卡尔曼平滑的事件相关电位单次提取

本研究提出一种事件相关电位单次提取方法,可有效减少实验次数,并可探索实验之间ERP的变异性。此方法基于小波和卡尔曼平滑,首先利用小波变换考察ERP平均信号的时频特性,根据ERP不同分量出现的时间位置,在不同尺度上选取特定的单次实验ERP小波系数构成观测向量,其为真实ERP小波系数状态向量与噪声之和,然后对观测向量进行卡尔曼平滑,最后对卡尔曼平滑后的小波系数进行小波重构,得到单次提取的ERP信号。仿真实验表明,基于小波和卡尔曼平滑的方法不仅信噪比提高约16~18 dB,优于30次叠加平均、简单小波方法和基于高斯基函数的卡尔曼滤波方法,还可以跟踪ERP的幅度趋势变异性。与基于高斯基函数的卡尔曼滤波方法相比,所提方法降低了计算量。真实脑电ERP提取实验表明本方法较好地从单次记录中提取出了事件相关电位,并可解释ERP因适应和应激引起的趋势变异性。     

正常儿童汉字语义事件相关电位的研究

目的：探讨单个汉字语义刺激正常儿童的事件相关电位，对三种不同类别（有关联、无关联、假字）ERP的特征进行比较研究。方法：对31名10岁的儿童采用加拿大Stellate systems32道数字化无纸脑电图仪，并用单个汉字语义刺激模块进行检测。刺激信号同步触发，脑电图（EEG）同步记录，从EEG中提取三种不同类别刺激的ERP，对P2和N2进行分析。结果：单个汉字语义有戈联的P2及N2潜伏期与无关联，假字组相比有显著性差异（P〈0．01）；波幅无显著性差异（P〉0．05）；N2波广泛分布头皮各区，左右大脑半球无明显差异（P〉0．05）。结论：三种不同类别的ERP波形及潜伏期各不相同；N2是语义刺激ERP的主成分，P2可认为与儿童语义的早期理解有关。     

儿童数学认知的ERP研究

目的:通过分析儿童数学认知的ERP波形特征,探讨儿童的数学认知过程。方法:选择小学二年级和五年级学生各20名,采用20以内加减计算及相应答案作为刺激内容,进行ERP检测并进行分析。结果:①两组儿童的ERP波形成分一致,计算时主要包括N1,P2,N2,P3,N3;答案判断时主要包括N1,P2,N2,P3。②计算时五年级儿童的N2下降支比二年级儿童下降快且P3潜伏期短。③错误答案的N2波幅比正确答案高。④计算时大脑两侧相关区域均有参与,颞、前额、顶枕部相继被激活,后期阶段主要集中在前额及顶枕部。结论:①不同年龄儿童计算时的ERP成分稳定且一致,其中不同年龄间的差异主要体现在N2下降支及P3潜伏期。②答案判断是一个不同于计算的认知过程,而且在正确与错误的判断上也存在心理差异。     

基于小波变换和盲源分离算法提取事件相关电位

阐述了用小波分解和盲源分离(blind source separation,BSS)算法结合来去除噪声和干扰提取事件相关电位(event-related potential,ERP).采用小波变换分解ERP,抽取出不同频带的细节信息;由小波系数判断选择多个尺度的子带信号,将它们分别与原始ERP组合进行盲分离,方法是极大化信号时间上的可预测性;将分离的结果进一步叠加平均.两类ERP仿真实验结果表明,本文算法提取出的ERP主要成分波明显,易于辨识,信噪比比较单独运用盲分离算法提取出的结果要好.在应用实例中,有效地增强了ERP的μ波.该算法优点在于减少了刺激次数和波形失真,参数变化范围小,在临床上有很好的应用前景.     

正常儿童视觉空间注意ERP的研究

目的：研究正常儿童空间视觉注意刺激诱发的事件相关电位（Event-Related Potentials ERP）的特征.方法：采用有效提示、无效提示刺激模块（即Posner Cue）对30名8岁儿童进行检测.刺激信号同步触发,数字化脑电图（EEG）同步记录,使用德国的Besa软件从中提取ERP进行分析.结果：同一导联脑枕后部同一导联有效提示的N1、P2波幅大于无效提示（P＜0.05）,潜伏期无差异（P＞0.05）;脑顶前部有效提示的P1波幅大于无效提示,N1波幅则小于无效提示（P＜0.05）,潜伏期无差异（P＞0.05）;脑顶前部导联的N1潜伏期长于枕后部导联（P＜0.05）.结论：处理有效刺激的投入大收益也大,处理无效刺激的投入小收益也小,但儿童易受差异信息的干扰使得收益发生改变：二者的处理时程相似.     

大学生长潜伏期听觉诱发电位与感觉寻求人格特征的相关性分析

目的：研究大学生长潜伏期听觉诱发电位与感觉寻求人格特征的相关性。方法：对79名大学生进行感觉寻求人格测试，并采用70、80、90、100dB4种短纯音刺激检测其长潜伏期听觉诱发电位。结果：大学生具有较为突出的去抑制人格特征；Cz、C3、C4部位N1、P2潜伏期随刺激强度的增加而缩短；N1、P2以及N1／P2波幅随刺激强度的增加而增加；高感觉寻求者Cz、C3、C4部位20min后再测的波幅／刺激强度函数（ASF）斜率明显减小，与首次测试相比差异具有显著意义。结论：长潜伏期听觉诱发电位的强度依赖性及快速习惯化现象，可能成为感觉寻求人格特征的神经电生理标志。     

脑卒中后抑郁症患者治疗前后事件相关电位P300变化的对比研究

目的:比较脑卒中后抑郁症患者在治疗前后的事件相关电位(ERP)P300的改变特征,为客观评价临床疗效和早期诊断抑郁症提供更灵敏的参考依据.方法:从住院治疗的卒中后抑郁症患者中选60例作为研究组,分别观测治疗前后P300之潜伏期与波幅变化.结果:与治疗后相比较,治疗前波形不稳定,N1、N2、P3波潜伏期延迟,P3波波幅降低.结论:ERP P300波之潜伏期与波幅可以作为评价抑郁症临床疗效的参考指标.     

Renal dysplasia and asplenia in two sibs

A family is reported in which two sibs, one male and the other female, both died within 24 hours of birth with enlarged polycystic kidneys. Postmortem histology in the second child showed gross renal dysplasia. In both children the pancreas was enlarged, nodular and cystic but the liver appeared macroscopically normal. In the second child, histological examination confirmed pancreatic fibrosis with cystic dilation of ducts, but showed portal fibrosis with bile duct proliferation in the liver.
This combination of findings is very reminiscent of those in a girl and her brother reported by Ivemark et al. (1959). The children reported here also showed absence or hypoplasia of the spleen, cardiac anomalies and other features of the Ivemark syndrome (Ivemark 1955), a quite different, usually sporadic, congenital disorder. It is suggested that the children described here have a distinct lethal congenital disorder, probably inherited in an autosomal recessive manner.     

Schizophrenia in a North Swedish geographical isolate, 1900–1977. Epidemiology, genetics and biochemistry

Over 200 schizophrenic patients belonging to three major and interrelated pedigree complexes have been investigated over the past 30 years in a North Swedish geographically isolated population, presently numbering about 6,000. An intensive investigation of a number of biochemical correlates and genetic markers in a few selected families belonging to one of the major pedigrees has indicated new strategies for the current research program.
Schizophrenia, as defined operationally, is significantly associated with decreased activities of two enzymes (1) blood platelet monoamine oxidase, (2) plasma dopamine-β-hydroxylase, and (3) with the genetic marker Gc² (group specific antigen). Both enzymes are subject to genetic variation. A positive score for linkage between schizophrenia and low plasma DBH activity has been calculated, but, so far, available data are insufficient for discrimination between linkage and partial contribution of genetically controlled low plasma DBH to the pathogenesis of the disease. Alternatively, both mechanisms could be involved.
As a model for continued research, schizophrenia is explained as based on a double dominant-recessive genotype (Aabb), representing a vulnerability which in about 50 % of cases develops into clinical schizophrenia. It is suggested that the dominant mutation (A) operates on or affects MAO activity, and that the recessive genotype (bb) is instrumental in low variates of DBH activity and very likely such variates within the normal range of physiological variation. Moreover, it is suggested that the combined effects of MAO- and DBH-reduced efficiency on the metabolism of e.g. dopamine could be an essential pathogenic mechanism for the schizophrenic illness which is segregating in this population.     

What will studies of Fulani individuals naturally exposed to malaria teach us about protective immunity to malaria?

There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub-Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide-treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.     

The dominant diseases of modernized societies as omega-3 essential fatty acid deficiency syndrome: Substrate beriberi

About 1900, modern food selection and processing caused widespread $\text{epidemics}$ of the B vitamin deficiency diseases of beriberi and pellagra which, for genetic reasons, often expressed as different diseases ranging from bowel and heart disease to dermatoses and psychoses. But the B vitamins merely help convert essential fatty acids (EFA) into the prostaglandin (PG) tissue regulators and it now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, we have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA (w3) of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA. Since substrate EFA is processed by many B vitamin catalysts, an EFA deficiency will mimic a $\text{panh}$ypovitaminosis B, i.e., a mixture of $\text{substrate}$ beriberi and $\text{substrate}$ pellagra resembling vitamin beriberi and pellagra but exhibiting as even more diverse $\text{endemic}$ disease. This would consitute a second stage of the Modern Malnutrition and explain why some workers now hold the dominant diseases of modermized societies to be new, nutritionally based, pellagraform yet lipid-related and to range, once again, from heart disease to psychosis. It is an assumption that our dominant diseases are unrelated to each other or are merely revealed by our diagnostic acumen and therapeutic success; and that hydrogenating millions of tons of food oils annually, to destroy the rancidity producing w3-EFA, is safe for $\text{primates}$. Extensive beriberiform disease is reported here in 32 typical cases taken from medical practice which responds strikingly to linseed oil supplements (60% w3-EFA) in confirmation of identical results in Capuchins.     

The universal muscular chain reaction,muscle spasm,Torsions, ruptures and extravasations. Chameleons of pathology and some manifestations of simple muscular disorders

Most bodily functions require the coordinated actions of complementary and supplementary paired muscle groups. Where this essential muscular cooperation is lacking, hollow organs may burst and others become literally screwed up, giving rise to many similar spastic diseases such as Torticollis, Twisted ovarian cyst, Torsion of the Testis, Volvulus of the intestines, Varicose Veins, Megacolon, Aortamegaly, Scoliosis, Erb's Palsy, Peyronie's Disease, Main-en-Griffe, Undescended Foot (Pes Cavus), Talipes, Strabismus. Spasm is “panenepidemic” and unclassified examples of Torsion Dystonia and Dyskinesia really are as common as debt and taxes.     

Class II HLA in Georgia Caucasus Tbilisi Georgians and their Mediterranean ancestry: The Usko Mediterranean languages

Georgia (or Sakartvelo in its own language) is a South Caucasus Mts. country with its easternmost part is enigmatically named Iberia, like the Iberian Peninsula, which may refer to rivers “Kura” and “Ebro” or their valleys respectively. Most of their inhabitants speak Georgian which is included within Dene-Caucasian group and Usko-Mediterranean subgroup of languages. The latter includes Basque, Berber, ancient Iberian-Tartessian, Etruscan, Hittite, Minoan Lineal A and others. In the present paper, HLA class II -DRB1 and -DQB1 alleles has been studied and extended haplotypes calculated. Most frequent haplotypes are also of Mediterranean origin (i. e.: (A*02-B*51)-DRB1*11:01-DQB1*03:01, (A*02-B*51)-DRB1*13:01-DQB1*06:03, or (A*24-B*35)-DRB1*01:01-DQB1*05:01) and DA genetic distances show that closest world populations to Georgians are Mediterraneans. Georgians also show common extended haplotypes ((A*02-B*51)-DRB1*11:01-DQB1*03:01, (A*02-B*13)-DRB1*07:01-DQB1*02:01 and (A*03-B*35)-DRB1*11:01-DQB1*03:01) with Svan people, a secluded population in North Georgia mountains. We can conclude that Georgians belong to a very old Mediterranean substratum according to both linguistics (Usko Mediterranean languages) and HLA genetics.     

'Very sore nights and days': the child's experience of illness in early modern England, c.1580-1720

Sick children were ubiquitous in early modern England, and yet they have received very little attention from historians. Taking the elusive perspective of the child, this article explores the physical, emotional, and spiritual experience of illness in England between approximately 1580 and 1720. What was it like being ill and suffering pain? How did the young respond emotionally to the anticipation of death? It is argued that children’s experiences were characterised by profound ambivalence: illness could be terrifying and distressing, but also a source of emotional and spiritual fulfilment and joy. This interpretation challenges the common assumption amongst medical historians that the experiences of early modern patients were utterly miserable. It also sheds light on children’s emotional feelings for their parents, a subject often overlooked in the historiography of childhood. The primary sources used in this article include diaries, autobiographies, letters, the biographies of pious children, printed possession cases, doctors’ casebooks, and theological treatises concerning the afterlife.     

Guidelines for the Validation and Use of Immunoassays for Determination of Introduced Proteins in Biotechnology Enhanced Crops and Derived Food Ingredients

Recent advancements in agricultural biotechnology have created a need for analytical techniques to determine introduced proteins in crops enhanced through modern biotechnology techniques. These proteins are expressed in plant tissues and may be present in food ingredients. Immunoassays are ideally suited for protein detection and may be used as both quantitative and threshold methods. Microplate ELISA and lateral flow devices are two of the most commonly used immunoassay formats for agricultural biotechnology applications. This paper provides general background information and a discussion of criteria for the validation and application of immunochemical methods to the analysis of proteins introduced into plants and food ingredients using biotechnology methods. It is the result of a collaborative effort of members of the Analytical Environmental Immunochemical Consortium. This collaborative effort represents the combined expertise of several organizations to reach consensus on establishing guidelines for the validation and use of immunoassays. Further, the paper offers developers and users a consistent approach to adopting the technology as well as aid in producing accurate and meaningful results.     

Ultracryotomy: development and application (with examples from the yeast cytology) (author's transl)

The preparation steps usually necessary for obtaining ultrathin frozen sections of biological material (chemical prefixation, enclosing, cryoprotective treatment, freezing, sectioning, and post-staining the sections for transmission electron microscopy) are submitted to a critical analysis. The application of cryo-ultramicrotomy, in particularly for cytochemical purposes, is reviewed. Fundamental considerations of chemical prefixation and poststaining are supported by examples from yeast cytology. Furthermore, the efficiency of the cryo-ultramicrotomy (electron optical resolution of ultrastructural details) is demonstrated on yeast cells and protoplasts.