A Field-Compatible Method for Interpolating Biopotentials

Mapping of bioelectric potentials over a given surface (e.g., the torso surface, the scalp) often requires interpolation of potentials into regions of missing data. Existing interpolation methods introduce significant errors when interpolating into large regions of high potential gradients, due mostly to their incompatibility with the properties of the three-dimensional (3D) potential field. In this paper, an interpolation method, inverse-forward (IF) interpolation, was developed to be consistent with Laplace's equation that governs the 3D field in the volume conductor bounded by the mapped surface. This method is evaluated in an experimental heart–torso preparation in the context of electrocardiographic body surface potential mapping. Results demonstrate that IF interpolation is able to recreate major potential features such as a potential minimum and high potential gradients within a large region of missing data. Other commonly used interpolation methods failed to reconstruct major potential features or preserve high potential gradients. An example of IF interpolation with patient data is provided to illustrate its applicability in the actual clinical setting. Application of IF interpolation in the context of noninvasive reconstruction of epicardial potentials (the inverse problem) is also examined. © 1998 Biomedical Engineering Society. PAC98: 8710+e, 0260Ed     

Problem‐maintaining circles: Case illustrations of formulations that truly guide therapy

The cognitive behaviour therapy (CBT) emphasis on treatment relevance in assessment, and on evidence‐based intervention, has led to an increasing focus on problem maintenance factors (vs. precipitants) in both its models of psychopathology and in its individual case formulations. This article describes the reasons for this growing focus, and presents a generic CBT model based on the functional analysis of “problem‐maintaining circles” (PMCs) of causes. Some samples of the profuse literature implicating PMCs in many psychological disorders are presented, and the utility of PMC‐based functional analysis, case formulation, or modelling of psychopathology is advanced, not only as a guide to selection of therapeutic interventions, but as an alternative to standard psychiatric diagnosis. A sampling of a taxonomy of such PMCs is presented. And finally, the clinical application of PMC‐based functional analysis, case formulation, and treatment selection is illustrated in five case illustrations drawn from a recent clinical caseload.     

大学生成就动机与情绪和行为问题的关系

目的：探讨大学生成就动机与情绪和行为问题的关系。方法：采用成就动机、自尊、特质焦虑、抑郁、孤独四个量表及问题行为问卷对403名大学生进行测查。结果：（1）大学生追求成功动机显著高于避免失败动机。②追求成功动机与自尊呈显著正相关．与焦虑、抑郁、孤独及外显问题行为呈显著负相关．避免失败动机与自尊等变量的相关模式与追求成功动机相反。（3）追求成功型大学生存自尊上的得分显著高于避免失败型，而在焦虑、抑郁、孤独及外显问题行为上的得分显著低于避免失败型。结论：大学生成功动机与情绪和行为问题存在较密切关系。     

Apical and basolateral expression of Aquaporin-1 in transfected MDCK and LLC-PK cells and functional evaluation of their transcellular osmotic water permeabilities

 Aquaporin-1 is present in the apical and basolateral membranes in proximal tubules and descending limbs of Henlé’s loop. In order to be able to study the routing of Aquaporin-1 and the regulation of Aquaporin-1-mediated transcellular water flow, we stably transfected LLC-PK₁ and MDCK-HRS cell lines with an Aquaporin-1 expression construct. LLC-PK₁ clone 7 and MDCK clone K integrated two and one copies, respectively, which was reflected in the amount of Aquaporin-1 mRNA expressed in both clones. The Aquaporin-1 protein levels, however, were similar. In both clones, immuno-electronmicroscopy showed extensive labelling of Aquaporin-1 on the basolateral plasma membrane, endosomal vesicles and the apical plasma membrane, including the microvilli. To measure transcellular water permeation, a simple method was applied using phenol-red as a cell-impermeant marker of concentration. In contrast to the native cell lines, both clones revealed a high transcellular osmotic water permeability, which could not be influenced by forskolin add/3-isobutyl-1-methylxanthine (IBMX) or the phorbol ester 12-O-tetradecanoyl 13-acetate (TPA). After glutaraldehyde fixation, it was inhibitable by HgCl₂. These results indicate that targeting of Aquaporin-1 to the apical and basolateral plasma membrane is independent of cell type and show for the first time that water flow through a cultured epithelium can be blocked by mercurial compounds. Received: 9 October 1996 / Received after revision: 3 January 1997 / Accepted: 8 January 1997     

Moving Mesh Method for Reconstructing Some Spread Sources in the Brain

The purpose of this paper is to propose a new algorithm for the analysis of biomagnetic field data obtained from magnetoencephalography (MEG) measurements. This new method overcomes two major problems faced by the current method of data analysis. The first problem is the need to determine the number of sites of brain activity before calculations can be performed. The second problem is inability of the analysis to provide any information regarding the volume of the brain activity. The new data analysis method, called the Moving Mesh Method (MMM), is capable of analyzing MEG data without the need to determine the number of sources beforehand. In addition, the MMM determines the location of brain activity as a three dimensional volume, instead of as a point source of activity. The MMM uses an iterative method of calculating the position of the sources to achieve greater accuracy, and a regularized g-inverse matrix to stabilize its solution. The feasibility of the MMM was examined by two methods. First, a computer simulation was used to confirm the MMM's capability to analyzing MEG data. In the second experiment, the MMM was applied to analyze somatosensory evoked fields obtained using a new imaging system (Shimadzu Biomagnetic Imaging System, Model-100). From the interpretation of the results, we have concluded that the MMM is a feasible method of biomagnetic data analysis.     

Cervical muscle response to trunk flexion in whiplash-type lateral impacts

The purpose of this study was to determine the response of the cervical muscles to increasing low-velocity, whiplash-type lateral impacts when the occupant is seated out of the recommended driving position (neutral posture). Twenty healthy volunteers were subjected to left lateral impacts of 4.1, 7.7, 10.5, and 13.7 m/s² acceleration, with their trunk flexed by 45° and laterally flexed to the right and left also by 45° at the time of impact. Bilateral electromyograms of the sternocleidomastoids, trapezii, and splenii capitis were recorded. Under these conditions of trunk-flexed postures, in a left lateral impact, muscle responses were of generally low magnitude with the trunk flexed to either the left or right. Even at the highest acceleration of 13.7 m/s², all muscles generated less than 37% of their known maximal voluntary contraction electromyogram. Also, in these left lateral impacts, the right splenius capitis showed a greater EMG response than the left splenius capitis regardless of whether the subject was flexed to the right or left at the time of impact. The right splenius capitis (the one contralateral to the left lateral impact direction) was more active than its counterpart. Compared to what is known for EMG responses with an occupant in the neutral posture, the right sternocleidomastoid (usually the most active muscle in a left lateral collision) was significantly less-active with trunk flexion than with neutral posture conditions (P<0.01). In the absence of bodily impact, the flexed trunk posture does not produce a biomechanical response that would increase the likelihood of cervical muscle injury in low velocity lateral impacts, and may lessen the risk of injury for some muscles.     

Accuracy of Quadratic Versus Linear Interpolation in Noninvasive Electrocardiographic Imaging (ECGI)

Electrocardiographic Imaging (ECGI) is a cardiac functional imaging modality, noninvasively reconstructing epicardial potentials, electrograms and isochrones (activation maps) from multi-channel body surface potential recordings. The procedure involves solving Laplace’s equation in the source-free volume conductor between torso and epicardial surfaces, using Boundary Element Method (BEM). Previously, linear interpolation (LI) on three-noded triangular surface elements was used in the BEM formulation. Here, we use quadratic interpolation (QI) for potentials over six-noded linear triangles. The performance of LI and QI in ECGI is evaluated through direct comparison with measured data from an isolated canine heart suspended in a human-torso-shaped electrolyte tank. QI enhances the accuracy and resolution of ECGI reconstructions for two different inverse methods, Tikhonov regularization and Generalized Minimal Residual (GMRes) method, with the QI-GMRes combination providing the highest accuracy and resolution. QI reduces the average relative error (RE) between reconstructed and measured epicardial potentials by 25%. It preserves the amplitude (average RE reduced by 48%) and morphology of electrograms better (average correlation coefficient for QI ∼ 0.97, LI ∼ 0.92). We also applied QI to ECGI reconstructions in human subjects during cardiac pacing, where QI locates ventricular pacing sites with higher accuracy (≤ 10 mm) than LI (≤ 18 mm).     

大学生寻求专业性心理帮助态度的预测因素研究

目的:探讨大学生寻求专业性心理帮助态度的预测因素。方法:选取700名不同年级、不同专业的大学生作样本,进行问卷调查。结果:以寻求专业性心理帮助态度为因变量,进行性别(2)×专业(2)的方差分析。结果发现,性别的主效应显著,F(1,615)=3.294,P=0.050。专业的主效应显著,F(1,615)=20.896,P=0.001。性别和专业的交互效应没达到显著性水平,F(1,615)=1.890,P=0.170。以寻求专业性心理帮助态度为因变量,回归分析结果得出R=0.636,R2=0.405,F=29.641,P=0.001,说明建立的回归方程是有意义的。结论:①对寻求专业性心理帮助态度有显著预测作用的变量按预测作用大小排序依次是:是否求助过、依赖的自我结构、自我隐藏度、专业、内控性和性别。②女生的寻求专业性心理帮助的态度比男生积极。③文体艺术类学生的寻求专业性心理帮助的态度比非文体艺术类学生积极。④自我结构是相互依赖的人寻求专业性心理帮助的态度积极。⑤自我隐藏度高的人寻求专业性心理帮助的态度消极。⑥内控者寻求专业性心理帮助的态度消极。     

Single dipole localization: Some numerical aspects and a practical rejection criterion for the fitted parameters

Summary There have been a number of attempts in the last years to localize the generators of brain electromagnetic activity, considering one current dipole as the source model. Single Dipole Localization (SDL) requires the selection of an optimization algorithm (OA). General aspects related with the selection, implementation and evaluation of some of the OA employed for SDL are discussed in this paper. Specifically the performance of two algorithms, those of Hooke-Jeeves and Levenberg-Marquardt, are tested by simulations. Suggestions for including restrictions to the dipole position and comments about some commonly used measures of the goodness of fit are given. Examples of erroneous implementations of these algorithms are also illustrated. A simple graphic rejection criterion, which can be easily used by inexperienced researchers, is introduced and tested in noisy and noise free simulations.The authors are grateful to Roberto D. Pascual Marqui for programming the Hooke-Jeeves algorithm.     

选择性破坏胰岛A细胞的大鼠空肠肌间神经丛胆碱能末梢VAChT的定量研究

目的　探讨胰岛A细胞与肠胆碱能神经的关系。方法　采用免疫组化SP方法检测硝酸钴选择性破坏胰岛A细胞的大鼠空肠肌间神经丛胆碱能末梢VAChT阳性反应物的变化 (注钴后 1,2 ,3,4,6 ,10d) ,并进行显微图象定量分析。结果　注钴后 2d开始 ,VAChT阳性反应物显著减少 (P <0 0 5 ) ;尤以 3,4d后最为显著 (P <0 0 1) ,10天后恢复。结论　胰岛A细胞可能参与肠胆碱能神经的功能调节