Fractal analysis of surface EMG signals from the biceps

The effect of the administration route, dose, and sampling time on the total urinary excretion of four major benzo[a]pyrene (BaP) metabolites, 3-hydroxyBaP (3-OHBaP), 9-hydroxyBaP 9-hydroxyBaP (9-OHBaP), trans-4,5-dihydrodiolBaP (4,5-diolBaP), and trans-9,10-dihydrodiolBaP (9,10-diolBaP), was studied in male Sprague-Dawley rats exposed to a single intravenous, oral, and cutaneous dose of 2, 6, 20, and 60 mumol BaP/kg. Urine samples were collected at 24-h intervals following treatment. Over the 0-72 h period and for a given dose, amounts of BaP metabolites were 3-OHBaP > 4,5-diolBaP > > 9-OHBaP following intravenous and oral dosing, and 3-OHBaP > > 9-OHBaP > or = 4,5-diolBaP after cutaneous treatment. 9,10-diolBaP was barely detected. On the other hand, amounts of 3-OHBaP and 4,5-diolBaP excreted in urine over the 0-72 h period and for a given dose appeared in the following order: intravenous approximately oral > or = cutaneous. Amounts of 9-OHBaP excreted varied as follows: oral > or = cutaneous > intravenous. For all routes of administration, excretion of 4,5-diolBaP was almost complete over the 0-24 h period in contrast with 3-OHBaP and 9-OHBaP. Peak excretion of 3-OHBaP and 9-OHBaP was reached in the 0-24 h period following intravenous and oral treatment and in the 24-48 h period following cutaneous application. Overall, for a given administration route and dose, there were variations in the time profiles between metabolites. In general, there was nonetheless a good correlation between the BaP dose and urinary excretion of 3-OHBaP, 9-OHBaP, and 4,5-diolBaP. Furthermore, total urinary excretion of a specific metabolite, its time profile, and the relative proportion of the metabolites studied depended on the administration route. Data also suggest that a measure of the concentration ratio of the different metabolites could reflect the time and main route of exposure.     

A structural explanation for the recognition of tyrosine-based endocytotic signals

Many cell surface proteins are marked for endocytosis by a cytoplasmic sequence motif, tyrosine-X-X-(hydrophobic residue), that is recognized by the mu2 subunit of AP2 adaptors. Crystal structures of the internalization signal binding domain of mu2 complexed with the internalization signal peptides of epidermal growth factor receptor and the trans-Golgi network protein TGN38 have been determined at 2.7 angstrom resolution. The signal peptides adopted an extended conformation rather than the expected tight turn. Specificity was conferred by hydrophobic pockets that bind the tyrosine and leucine in the peptide. In the crystal, the protein forms dimers that could increase the strength and specificity of binding to dimeric receptors.     

From magnetic resonance spectroscopy to classification of tumors. A review of pattern recognition methods

This article reviews the wealth of different pattern recognition methods that have been used for magnetic resonance spectroscopy (MRS) based tumor classification. The methods have in common that the entire MR spectra is used to develop linear and non-linear classifiers. The following issues are addressed: (i) pre-processing, such as normalization and digitization, (ii) extraction of relevant spectral features by multivariate methods, such as principal component analysis, linear discriminant analysis (LDA), and optimal discriminant vector, and (iii) classification by LDA, cluster analysis and artificial neural networks. Different approaches are compared and discussed in view of practical and theoretical considerations.     

ECG pattern recognition and classification using non-linear transformations and neural networks: a review

The most widely used signal in clinical practice is the ECG. ECG conveys information regarding the electrical function of the heart, by altering the shape of its constituent waves, namely the P, QRS, and T waves. Thus, the required tasks of ECG processing are the reliable recognition of these waves, and the accurate measurement of clinically important parameters measured from the temporal distribution of the ECG constituent waves. In this paper, we shall review some current trends on ECG pattern recognition. In particular, we shall review non-linear transformations of the ECG, the use of principal component analysis (linear and non-linear), ways to map the transformed data into n-dimensional spaces, and the use of neural networks (NN) based techniques for ECG pattern recognition and classification. The problems we shall deal with are the QRS/PVC recognition and classification, the recognition of ischemic beats and episodes, and the detection of atrial fibrillation. Finally, a generalised approach to the classification problems in n-dimensional spaces will be presented using among others NN, radial basis function networks (RBFN) and non-linear principal component analysis (NLPCA) techniques. The performance measures of the sensitivity and specificity of these algorithms will also be presented using as training and testing data sets from the MIT-BIH and the European ST-T databases.     

Discrimination of forearm''s motions by surface EMG signals using neural network

The effect of the antiviral, antitumoural xanthate D609 on the activity of phospholipase A2, C (PC- and Pi-specific) and D was investigated. D609 is the first model substance of a new concept of antiviral therapy that interferes with cellular regulation mechanisms, rather than with virus coded enzymes. Exclusively phosphatidylcholine (PC) specific phospholipase C (PC-PLC) was found to be inhibited in a dose-dependent manner. Enzyme activity was determined either as the rate of acid release from PC or as the rate of phosphorylcholine production form 3H labelled PC. Lineweaver-Burk plots revealed D609 as a competitive inhibitor of PC-PLC with a Ki of 6.4 microM. In addition, D609 competitively inhibited PC-PLC mediated cleavage of P-nitrophenylphosphorylcholine (p-NPP), a pseudo-substrate of PC-PLC with a Ki of 8.8 microM. These data suggest that D609 competes with the phosphorylcholine residue of PC for binding to PC-PLC.     

The salience of two cues for pattern recognition in the rat.

Models for pattern discrimination by rats have postulated either contour separation or orientation as major factors in the coding process. The postulates were tested by training 16 male hooded rats on pairs of oblong stimuli having (a) identical contour separation but different amounts of contour in the horizontal and vertical dimensions, or (b) identical horizontal and vertical components but different amounts of contour separation. For 2 orientations of form, discrimination occurred for stimuli of type a but not B. Factors including training order and part-figure or brightness discrimination did not affect pattern learning. Results, supporting a code based on contour orientation, are discussed in terms of physiological bases for pattern vision. (french summary) (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A pattern recognition account of decision making

In the domain of pattern recognition, experiments have shown that perceivers integrate multiple sources of information in an optimal manner. In contrast, other research has been interpreted to mean that decision making is nonoptimal. As an example, Tversky and Kahneman (1983) have shown that subjects commit a conjunction fallacy because they judge it more likely that a fictitious person named Linda is a bank teller and a feminist than just a bank teller. This judgment supposedly violates probability theory, because the probability of two events can never be greater than the probability of either event alone. The present research tests the hypothesis that subjects interpret this judgment task as a pattern recognition task. If this hypothesis is correct, subjects' judgments should be described accurately by the fuzzy logical model of perception (FLMP)--a successful model of pattern recognition. In the first experiment, the Linda task was extended to an expanded factorial design with five vocations and five avocations. The probability ratings were described well by the FLMP and described poorly by a simple probability model. The second experiment included (1) two fictitious people, Linda and Joan, as response alternatives and (2) both ratings and categorization judgments. Although the ratings were accurately described by both the FLMP and an averaging of the sources of information, the categorization judgments were described better by the FLMP. These results reveal important similarities in recognizing patterns and in decision making. Given that the FLMP is an optimal method for combining multiple sources of information, the probability judgments appear to be optimal in the same manner as pattern-recognition judgments.     

Similarity-scaling studies of dot-pattern classification and recognition.

Classification performance in a dot-pattern, prototype-distortion paradigm (e.g., M. I. Posner and S. W. Keele, 1968) was modeled within a multidimensional scaling (MDS) framework. MDS solutions were derived for sets of dot patterns that were generated from prototypes. These MDS solutions were then used in conjunction with exemplar, prototype, and combined models to predict classification and recognition performance. Across 3 experiments, an MDS-based exemplar model accounted for the effects of several fundamental learning variables, including level of distortion of the patterns, category size, delay of transfer phase, and item frequency. Most important, the model quantitatively predicted classification probabilities for individual dot patterns in the sets, not simply general trends of performance. There was little evidence for the existence of a prototype-abstraction process that operated above and beyond pure exemplar-based generalization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于规则的神经网络在模式分类中的应用

针对模式分类任务,提出一种基于粗糙集规则的神经网络构造方法.首先,利用粗糙集理论和遗传算法约简输入特征,在尽量保持分类能力不变的情况下降低条件属性维数,并推导出简练的分类规则集合.然后,以规则集为基础构造BP神经网络结构、确定网络层数、输入输出节点数等,并计算规则的条件属性重要度和依赖度2个参数对连接权值进行初始化.最后,通过一个实例验证了方法的有效性,结果表明该方法能有效解决传统神经网络构造难、解释难、过拟合等问题,提高了分类精度,降低了训练时间.此外,初步探讨了网络训练时对知识提炼的影响.     

Garner and congruence effects in the speeded classification of bimodal signals.

The role of attention in speeded Garner classification of concurrently presented auditory and visual signals was examined in 4 experiments. Within-trial interference (i.e., congruence effects) occurred regardless of the attentional demands of the task. Between-trials interference (i.e., Garner interference) occurred only under conditions of divided attention when making judgments about auditory signals. Of importance, the data show congruence effects in the absence of Garner interference. Such a pattern has been rarely reported in studies of the classification of purely visual stimuli and contradicts theoretical accounts asserting that the effects share a common locus. The data question the notion that Garner classification reveals fundamental insights about the nature of the perceptual processing of bimodal stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

EMG biofeedback training of Type A and Type B behavior pattern subjects.

Assessed the relative efficacy of EMG biofeedback training to reduce tension levels in Ss characterized either by the presence of the coronary-prone behavior pattern (Type A) or by its absence (Type B). 55 college students, classified as Type A or B on the basis of Jenkins Activity Survey (Form T) scores, were randomly assigned to either a biofeedback or a control group. Ss met for 6 training sessions, then returned for a 7th session to perform without biofeedback a series of easy (4-digit recall) and difficult (7-digit recall) tasks. Biofeedback Ss attained a greater degree of relaxation during training than did control Ss, regardless of A/B status. Also, biofeedback Ss maintained greater relaxation during task performance than did control Ss. Across groups, Type A's performed significantly better than Type B's on difficult tasks, and although Type A biofeedback Ss had EMG levels as high as Type B controls for the actual duration of performance tasks, they maintained significantly lower EMG levels than either group prior to, between, and after performance tasks. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

模式识别技术在高炉炼铁过程控制中的应用

用计算机控制高炉过程一直是一个重要的研究方向,近年来随着信息技术的发展,越来越多的信息优化技术被用到了高炉过程的研究中,从模式识别、机器学习的角度来对高炉过程进行研究已经成为一种重要的研究方向。根据高炉过程的特点,提出可以进行模式识别研究的方向,并对国内外及武钢在高炉过程模式识别领域所作的工作进行总结,如利用模式识别技术评估高炉煤气流的变化、识别高炉布料变化、识别炉身温度变化特征、识别高炉软熔带变化类型、对炉温过程进行预报等。     

A computer-based statistical pattern recognition for Doppler spectral waveforms of intracranial blood flow

The effects of 2 months treatment with simvastatin (40 mg, 20 mg p.o. daily) or placebo on erythrocyte membrane cholesterol content and acyl chain composition have been studied in 36 patients with a clinical history of atherosclerosis enrolled in the Oxford Cholesterol Study. All patients received advice corresponding to a standard phase 1 cholesterol-lowering diet. As expected the mean serum total cholesterol fell substantially (-26.5%, 20 mg simvastatin, P < 0.05; -32.7%, 40 mg simvastatin, P < 0.05) compared to placebo (-6.3%, ns). However, mean erythrocyte cholesterol content did not change significantly in any group (2 months therapy: 20 mg simvastatin, -0.62%; 40 mg simvastatin, +2.2%; placebo, -4.2%). Erythrocyte cholesterol was also unaltered after 5 months of therapy. Erythrocyte osmotic fragility was unchanged in the treatment and placebo groups. In the placebo group dietary advice alone was associated with a significant increase in the linoleic acid content of erythrocytes from 9.4 mole% of total acyl chains to 11.8 mole% (P < 0.05). Treatment with simvastatin was associated with an increase in the arachidonic acid content of the erythrocyte membrane from 12.2 to 15.3 mole% (P < 0.05). Treatment with simvastatin does not alter erythrocyte cholesterol content, but does alter acyl chain distribution. These results suggest that the chemical potential of cholesterol in serum is not markedly altered by HMG-CoA reductase inhibition.     

Structure prediction: folding proteins by pattern recognition

Although we are still a long way from being able to predict the details of protein structure from the underlying chemistry, slow but steady progress is being made at modeling structural features by recognizing the patterns that connect sequence to structure.     

Development of pattern classification: Auditory-visual equivalence in the use of prototypes.

Studied the development of the relation between skills of visual and auditory pattern classification at the Grade 2, Grade 6, and adult (N?=?108) age levels using visual and auditory representations of the same abstract information. Ss were required to say whether the 2 patterns in each intramodal problem came from the same class. The questions of interest were whether pattern structure is processed independently of presentation modality and whether there is change or continuity with development in the use of visual and auditory pattern characteristics in classification. Results provide evidence of common processing of pattern class structure for the modalities, patterns, prototypes, and age range studied. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of autonomous neural network systems to medical pattern classification tasks

This paper presents a study of the application of autonomously learning multiple neural network systems to medical pattern classification tasks. In our earlier work, a hybrid neural network architecture has been developed for on-line learning and probability estimation tasks. The network has been shown to be capable of asymptotically achieving the Bayes optimal classification rates, on-line, in a number of benchmark classification experiments. In the context of pattern classification, however, the concept of multiple classifier systems has been proposed to improve the performance of a single classifier. Thus, three decision combination algorithms have been implemented to produce a multiple neural network classifier system. Here the applicability of the system is assessed using patient records in two medical domains. The first task is the prognosis of patients admitted to coronary care units; whereas the second is the prediction of survival in trauma patients. The results are compared with those from logistic regression models, and implications of the system as a useful clinical diagnostic tool are discussed.     

Auditory pattern classification: Continuity of prototype use with development.

Studied the development of the ability to classify auditory patterns in 26 males and 26 females at each of 5 age levels: 2nd, 6th, 10th, and 12th grades, and adult (undergraduates). Ss were required to state whether each 5-element pure tone sequence came from the training class. Both accuracy and feature use in classification were remarkably consistent across age, and regression analyses indicated that the age changes were due to differences in perceptual achievement rather than process. Performance at all age levels was highly predictable from the physical pattern characteristics, in particular, the similarity between patterns and their prototypes. Results are similar to those obtained in an analogous developmental study by L. S. Aiken and T. M. Williams (1973) involving visual patterns, and suggest that the processes of pattern perception are applicable across stimuli, modalities, and the age range studied. (PsycINFO Database Record (c) 2010 APA, all rights reserved)