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PubMedDate not supplied

Origin attribution of polychlorinated dibenzo-p-dioxins and dibenzofurans in sediment and soil from a Japanese freshwater lake area through congener-specific data analysis.

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in sediment and soil from a freshwater lake area were congener-specifically determined. The obtained data were examined to estimate the major origins of these compounds, with the aid of principal component analysis (PCA). Four major principal components (PCs) were obtained, and three of them were attributed to PCDDs/PCDFs in the atmosphere, in a diphenyl ether herbicide and in pentachlorophenol, based on congener-specific comparisons with references. One PC remained unattributed. These four were interpreted as the major origins of PCDDs/PCDFs in the area. The relative influence of the origins was also investigated.

Agriculture↗
PubMed2001

Fuel spill identification using solid-phase extraction and solid-phase microextraction. 1. Aviation turbine fuels.

The water-soluble fraction of aviation jet fuels is examined using solid-phase extraction and solid-phase microextraction. Gas chromatographic profiles of solid-phase extracts and solid-phase microextracts of the water-soluble fraction of kerosene- and nonkerosene-based jet fuels reveal that each jet fuel possesses a unique profile. Pattern recognition analysis reveals fingerprint patterns within the data characteristic of fuel type. By using a novel genetic algorithm (GA) that emulates human pattern recognition through machine learning, it is possible to identify features characteristic of the chromatographic profile of each fuel class. The pattern recognition GA identifies a set of features that optimize the separation of the fuel classes in a plot of the two largest principal components of the data. Because principal components maximize variance, the bulk of the information encoded by the selected features is primarily about the differences between the fuel classes.

Journal Article↗
PubMed1996

Kinematic determinants of human locomotion.

1. The aim of this study was to find kinematic patterns that are invariant across the normal range of locomotion speeds. Subjects walked at different, freely chosen speeds ranging from 0.9 to 2.1 m s-1, while motion and ground reaction forces on the right side of the body were recorded in three-dimensional space. 2. The time course of the anatomical angles of flexion-extension at the hip and ankle was variable not only across subjects, but even from trial to trial in the same subject. By contrast, the time course of the changes in the angles of elevation of each limb segment (pelvis, thigh, shank and foot) relative to the vertical was stereotyped across subjects. 3. To compare the waveforms across speeds, data were scaled in time relative to gait cycle duration. The pattern of ground reaction forces was highly speed dependent. Several distinct families of curves could be recognized in the flexion-extension angles at the hip and ankle. Instead, the waveforms of global length and elevation of the limb, elevation angles of all limb segments and flexion-extension at the knee were invariant with speed. 4. When gait trajectories at all speeds are plotted in the position space defined by the elevation angles of the limb segments, they describe regular loops on a plane. The statistical characteristics of these angular covariations were quantified by means of principal component analysis. The first two principal components accounted together for > 99% of the total experimental variance, and were quantitatively comparable in all subjects. 5. This constraint of planar covariation of the elevation angles is closely reminiscent of that previously described for the control of posture. The existence of laws of intersegmental co-ordination, common to the control of posture and locomotion, presumably assures the maintenance of dynamic equilibrium during forward progression, and the anticipatory adaptation to potentially destabilizing factors by means of co-ordinated kinematic synergies of the whole body.

Adult↗
PubMed2006

Partial least squares regression calibration for determining wax content in processed flax fiber by near-infrared spectroscopy.

The quality of flax fiber in the textile industry is closely related to the wax content remaining on the fiber after the cleaning process. Extraction by organic solvents, which is currently used for determining wax content, is very time consuming and produces chemical waste. In this study, near-infrared (NIR) spectroscopy was used as a rapid analytical technique to develop models for wax content associated with flax fiber. Calibration samples (n=11) were prepared by manually mixing dewaxed fiber and isolated wax to provide a range of wax content from 0 to 5%. A total of fourteen flax fiber samples obtained after a cleaning process were used for prediction. Principal component analysis demonstrated that one principal component is enough to separate the flax fibers by their wax content. The most highly correlated wavelengths were 2312, 2352, 1732, and 1766 nm, in order of significance. Partial least squares models were developed with various chemometric preprocessing approaches to obtain the best model performance. Two models, one using the entire region (1100-2498 nm) and the other using the selected wavelengths, were developed and the accuracies compared. For the model using the entire region, the correlation coefficient (R2) between actual and predicted values was 0.996 and the standard error of prediction (RMSEP) was 0.289%. For the selected-wavelengths model, the R2 was 0.997 and RMSEP was 0.272%. The results suggested that NIR spectroscopy can be used to determine wax content in very clean flax fiber and that development of a low-cost device, using few wavelengths, should be possible.

Calibration↗
PubMed2004

Genetic algorithms for classification of olfactory stimulants.

We have developed and tested a genetic algorithm (GA) for pattern recognition, which identifies molecular descriptors that optimize the separation of the activity classes of olfactory stimulants in a plot of the two or three largest principal components of the data. Because principal components maximize variance, the bulk of the information encoded by these descriptors is about differences between olfactory classes in the dataset. In addition, the GA focuses on those classes and or samples that are difficult to classify as it trains using a form of boosting to modify the fitness landscape. Boosting minimizes the problem of convergence to a local optimum, because the fitness function of the GA is changing as the population is evolving toward a solution. Over time, compounds that consistently classify correctly are not as heavily weighted in the analysis as compounds that are difficult to classify. The pattern recognition GA learns its optimal parameters in a manner similar to a neural network. The algorithm integrates aspects of both strong and weak learning to yield a "smart" one-pass procedure for feature selection and classification.

Algorithms↗
PubMed2003

Biomarkers of aging in women and the rate of longitudinal changes.

The purposes of this study were (1) to estimate biological age score (BAS) in Japanese healthy women based on the 4-7 years longitudinal data for physiological, hematological and biochemical examinations and (2) to examine the rate of aging changes in adult women based on the estimated BAS. The samples consisted of cross-sectional (n=981) and longitudinal (n=110) groups. Out of 31 variables examined, five variables (forced expiratory volume in 1.0 s, systolic blood pressure, mean corpuscular hemoglobin, glucose, albumin/globulin ratio) that met the following criteria: 1) significant cross-sectional correlation with age; 2) significant longitudinal change in the same direction as the cross-sectional correlation; and (3) assessment of redundancy, were selected as candidate biomarkers of aging. This variable set was then submitted into a principal component analysis, and the first principal component obtained from this analysis was used as an equation for assessing one's BAS. Individual BAS showed a high longitudinal stability of age-related changes, suggesting high predictive validity of our newly developed aging measurement equation. However, changes in the aging rate based on the estimated BAS were not constant. The mean slopes of the regression lines of BAS for the three age groups (age<45, 45</=age<65 yrs, 65</=age) were 0.095, 0.065, 0.138, respectively. One-way analysis of variance detected a significant difference (F=5.14, p<0.01) among the three age groups. These results suggest that the rate of aging in adult women is relatively slower until 65 years of age, but after 65, the rate of aging shows a rapid increase. We concluded that the longitudinal method used for selection of variables to compute the BAS was useful and theoretically valid compared to those obtained from cross-sectional data analysis.

Adaptation, Physiological↗
PubMed1990

QSAR of acridines. II. Features of nitracrine analogs for high anti-tumor activity and selectivity on mice, searched by PCA and MRA methods.

A study of quantitative structure-activity relationships (QSAR) of 32 nitro-9-aminoacridine derivatives has been carried out. The results of the four biological tests in vitro, anti-tumor activity against S-180 and toxicity on healthy as well as on tumor bearing mice were subjected to principal component analysis (PCA). Two significant principal components PC1 and PC2 (containing 81.4% and 8.1% of total data set information, respectively) were extracted. The biological meaning of PCs was identified: PC1 corresponds to a general biological activity, PC2 mainly to selectivity. To obtain predictability of biological activities multiple regression analysis (MRA) for PC1 and PC2 were used. The general biological activity (PC1) is parabolically dependent on the lipophilicity (log P*) of the substituent on 9-amino group (R = 0.97); selectivity (PC2), however, on the shape index 2K and the indicator variable IN2N (R = 0.76). For high antitumor activity and improved therapeutic effectivity (LD50/ED50) 1-nitro-9-amino-acridines should be characterized by: (i) lipophilicity, expressed as log P*, between -1 and -2; (ii) three or more methylene spacers between proximal and distal nitrogen atoms in the side chain, if the distal nitrogen is present; (iii) high 2K value for the side chain, as for a large and preferably unbranched substituent on C9.

Aminoacridines↗
PubMed1989

Chemometric studies of some trace elements in cows' milk.

The matrix of the correlation between the concentrations of 11 trace elements determined in 45 samples of cows' milk was used as a starting matrix for principal component analysis. The space dimension was reduced from 11 variables to 5 principal components, accounting for about 80% of the total variance. After an orthogonal rotation, the first factor (F1) was found to be positively correlated with Cr, Mn, and Fe, F2 positively correlated with Ni and negatively with Cu, F3 positively with Cd and Pb, F4 positively with Zn, Sr, and Mo and F5 positively correlated with A1 and Sr. Element clusters appear to be determined by their origin. Some clusters are confirmed by principal factor analysis. A plot of the principal component scores was also applied to the differentiation of Italian Milk from different geographical origins.

Animals↗
PubMed2005

Estimation of peroneal and tibial afferent activity from a multichannel cuff placed on the sciatic nerve.

The afferent signals recorded with a multi-electrode cuff on the sciatic nerve were employed to investigate the possibility of extracting components ascending from the peroneal and tibial nerves. Two methods, an inverse regression model and principal component method, were studied. The parameters of inverse regression model, determined by data collected in semistatic conditions, were validated by data collected in dynamic conditions. The results showed that the regression model, which used only two channels of the sciatic recordings, was sufficient to separate the distal afferent components. The model, at the expense of requiring distal branch recordings for estimating model parameters, yielded better separation than the principal component method. In conclusion, peroneal and tibial afferent activity can be estimated from the sciatic nerve: the principal component method is suitable for applications focused on acquiring afferent information, whereas the inverse regression model is better for applications in which stimulations will be applied to the branches. The estimation technique provides a powerful tool for in vivo investigation of sensory information transmitted in a peripheral nerve and facilitates implementation of advanced functional neuromuscular stimulation systems.

Afferent Pathways↗
PubMed2006

Face recognition using IPCA-ICA algorithm.

In this paper, a fast incremental principal non-Gaussian directions analysis algorithm, called IPCA-ICA, is introduced. This algorithm computes the principal components of a sequence of image vectors incrementally without estimating the covariance matrix (so covariance-free) and at the same time transforming these principal components to the independent directions that maximize the non-Gaussianity of the source. Two major techniques are used sequentially in a real-time fashion in order to obtain the most efficient and independent components that describe a whole set of human faces database. This procedure is done by merging the runs of two algorithms based on principal component analysis (PCA) and independent component analysis (ICA) running sequentially. This algorithm is applied to face recognition problem. Simulation results on different databases showed high average success rate of this algorithm compared to others.

Algorithms↗
PubMed2004

Solvent toxicity in organic-aqueous systems analysed by multivariate analysis.

The effect of several solvents present in a biphasic reaction system on cells of Rhodococcus erythropolis DCL14, Xanthobacter Py2, Arthrobacter simplex and Mycobacterium sp. NRRL B-3805 was evaluated. These four strains have been widely exploited, from bioremediation to the production of fine chemicals, in two-phase reaction media. The solvents tested were ethyl butyrate, n-hexane, cyclohexane, iso-octane, n-dodecane, DMSO, bis(2-ethylhexyl) phthalate and fluorinert FC-70. The cell population was monitored by fluorescence microscopy and analysis of the images captured provided single-cell-level information on cell viability, morphological factors of both viable and non-viable cells, and on the number of viable cells in clusters. These data, and those concerning the initial carveol concentration, the carbon source used during growth, the adaptation time to the solvent prior to substrate addition, and the properties of the organic solvent, were interpreted using principal components analysis (PCA). For R. erythropolis, X. Py2, and A. simplex, between 70.1 and 80.4% of the variability of the data could be explained by six principal components, while 86.7% of the variance in the results obtained with Mycobacterium sp. could be represented by seven principal components. In all cases, solvent toxicity could explain over a third of the variability in the data. R. erythropolis cells were able to maintain their viability under harsh conditions. A period of contact between cells and solvent, prior to the addition of substrate, was prejudicial for R. erythropolis and A. simplex cells, at least for the most toxic solvents, but was beneficial for X. Py2 cells. The number of Mycobacterium sp. cells in clusters was lower after an adaptation period compared to the number of cells in aggregates when the substrate was added at time zero. The substrates transformed by R. erythropolis and A. simplex cells increased the toxicity of the system by decreasing the log P of the reaction mixture. Hydrocortisone was responsible for a reduction in the ability of A. simplex to respond to stress conditions. Mycobacterium sp. cells were apparently unaffected by beta-sitosterol. The results obtained are useful for the design of more efficient two-phase reaction systems where solvent toxicity may be overcome in order to increase cell productivity.

Algorithms↗
PubMed1989

[Multivariate statistical analysis in stabilometry in human upright standing (second report)--pattern recognition of a stabilogram].

A pattern of a figure which is displayed by an X-Y recorder or by a polygraph in stabilometry may present several qualitative facts about the standing ability of a test-subject. The purpose of this study was to make a quantitative evaluation of the body stability in both normal and ataxic patients who were standing erect. The technique utilised was pattern-recognition, composed of principal component analysis and discriminant analysis. Stabilometrical examinations were carried out in 20 normal subjects, 39 with peripheral vestibular disturbance and 11 with disturbance of the central origin. Each examinee was ordered to keep an upright posture for 60 seconds both with the eyes open and with the eyes closed. The following parameters were used: the area of the ellipse for rejection by a statokinesigram, the maximum width and the total length of body excursion, the root mean square, the velocity, the acceleration and the average frequency in the horizontal plane. These were the same parameters that were used in the first report. Each component predicting a specific character in stabilometry was identified by this study of principal component analysis. The relationship between the components in order and its prediction were as follows: the first component predicted the size of the body movement, the second the force, the third the density, the fourth the difference between body movement with the eyes open and with the eyes closed and the fifth the direction of body sway. Furthermore, the principal components were successfully utilized to allow the classification of the test subjects into three groups: those who were normal, those with peripheral vestibular disturbance and those with disturbance of the central origin. Discriminant functions were also used to classify the above mentioned three groups and another five groups, namely: those who were normal, those with vestibular neuronitis, those with positional vertigo of the benign paroxysmal type, those with Ménière's disease and those with cerebellar ataxia. In classification of the three groups, the significant parameters used for discrimination were as follows (P less than 0.05): the root mean square with the eyes open, the distance and the maximum width of body excursion in the Y direction with the eyes open, the area of the ellipse for rejection both with the eyes open and with the eyes closed, the maximum width and the average frequency in the X direction with the eyes closed.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

Multivariate analysis of body shape in fragile X (Martin-Bell) syndrome.

Human body shape measures can be more informative in studies of developmental abnormalities than distances between body landmarks. Such measures were obtained by an appropriate transformation of 34 distances between trunk/limbs and head/face landmarks in 43 men and 72 women with the Martin-Bell Syndrome (MBS), and in 99 and 103 normal men and women, respectively. The transformation of the original distances was performed by adjusting individual measures for an overall size measure using regression analysis. Thus obtained body shape variables were used in discriminant analysis in order to obtain unbiased classification probabilities of individuals having the MBS or being normal. The average percent correctly classified male and female individuals was high (93 and 87, respectively). Moreover, the body shape variables were used to obtain shape dimensions by means of principal component analysis. There was no difference between the MBS and normal individuals in the first (most important) principal component (shape dimension). This component represents the relative proportions between trunk and limb lengths and widths, or between midfacial lengths and widths. However, there were appreciable differences in some succeeding components. The problem of interpretation of shape dimensions as derived from principal component analysis and of their relevance to abnormal development in the MBS individuals is discussed.

Adolescent↗
PubMed2001

Effect of glutamate analogues on red-green opponent interaction in monkey electroretinograms.

The effect of glutamate analogues on red-green opponent interaction was electrophysiologically investigated in anesthetized cynomolgus monkeys (Macaca fascicularis). Two approaches were employed: amplitude measurement and principal component analysis. Electroretinograms were recorded for 23 monochromatic stimuli (400-700 nm) at an equal energy with white light adaptation before and after treatment with the glutamate analogues, 2-amino-4-phosphonobutyric acid, cis -2,3-piperidine-dicarboxylic acid, or both. Before treatment, although spectral amplitude curves of the a- and d-waves showed single, broad peaks at about 550 nm, the b-wave curve had three peaks at about 460, 540 and 600 nm, indicating the occurrence of the red-green opponent interaction. Principal component analysis performed on these waveforms extracted three components with short, middle, and long wavelength peaks, well defined characteristics of the red-green opponency. After vitreal injection of 2-amino-4-phosphonobutyric acid, the a- and d-wave amplitudes were enhanced while the b-wave amplitude was almost completely diminished. However, principal component analysis showed basically similar characteristics to those before drug, suggesting that the red-green opponency was not affected. In contrast, after application of cis -2,3-piperidine-dicarboxylic acid, the a- and d-waves were diminished and the b-wave was enhanced as expected, however the enhancement was observed only in the short and middle wavelengths. As a result of this partial enhancement, the b-wave spectral amplitude curve showed only a single peak, unlike in the control. In addition, principal component analysis revealed a quite different result from the control; only two components with short and middle wavelength peaks and the component with long wavelength peak disappeared. Similar two components were also separated after the conjunction of both drugs. These results demonstrate that red-green opponency is greatly inhibited by cis -2,3 piperidine-dicarboxylic acid, and thus suggest that horizontal cells are related to a generation of the red-green opponency through a cone type selective or nonselective negative feedback.

Animals↗
PubMedDate not supplied

Development and phenotypic correlations: the evolution of tooth shape in Sorex araneus.

Do morphogenetic processes cause common patterns of phenotypic covariation, and do those patterns evolve over microevolutionary timescales? Evolution of molar shape variance-covariance (P) matrixes was studied in five populations of the common shrew, Sorex araneus. P matrix evolution was assessed using matrix correlation, matrix disparity, and common principal component analysis (CPCA). Significant changes in covariance structure were found among the populations, but the differences were small. A computer model was used to estimate the theoretical covariance introduced into the phenotype by developmental interactions. Molar developmental processes explained some of the covariance in the shrew samples, especially as measured by matrix correlation, but the proportion was relatively small. Developmental principal components (PCs) were only infrequently associable with common principal components. The results suggest that molar shape P matrixes can evolve quickly in a manner only loosely constrained by development, and that their shared covariance is probably dominated by factors more proximate than development. Rarefaction showed that sample size severely affected P comparisons when n < 15 for matrix correlation and disparity, and when n < 30 for CPCA. Among CPCA evaluation criteria, Akaike Information Criterion performed better than jump-up at n < 30, but worse at n > 30.

Animals↗
PubMed1989

An assessment of the existence of muscle synergies during load perturbations and intentional movements of the human arm.

A cross-correlation analysis was performed on EMG activities in elbow and shoulder flexors evoked by force perturbations acting in different directions on the forearm and during intentionally generated movements with the purpose of characterizing the temporal relationships between patterns of activation of different muscles. Qualitatively it was found that the shape of the cross-correlation function differed from one experimental condition to the next. A principal component analysis permitted a quantitative assessment of this point. In general it was found that two principal components could account for the data. Furthermore when the cross-correlograms are represented in principal component space, there was no clustering of the data points. Several possible definitions of 'muscle synergies' are discussed from the perspective of this finding. It is concluded that the most restrictive definition is incompatible with the data. Less restrictive definitions, while compatible with the data, do not lead to a simplification of the control problem.

Arm↗
PubMed1991

[Morphometrical study of physical growth of laboratory-bred cynomolgus monkeys aged from zero to 9 years].

The relative growth was examined in laboratory-bred cynomolgus monkeys (Macaca fascicularis) aged from zero to 9 years. The principal component analysis and multivariate allometry were applied to the biometrical data. As the result of the principal component analysis, the cumulative contribution ratio of the 1 st (PC 1) and 2 nd (PC 2) principal components accounted for 99.0 percent. According to the eigen vector values of each morphological site (14 sites), PC 1 was acceptable not only as a size factor but also as a shape factor of the morphological growth changes from birth to the 3rd year of life in both sexes. PC 2 was acceptable as a shape factor of the morphological differences between sexes after the 3rd year of life. As the result of the multivariate allometric analysis applied to the same data, proximate sites of the trunk showed relatively high growth rates compared to distal ones of the trunk. The head, limbs and arms grew slowly in contrast to the trunk. Thus, we could demonstrate the relative growth of cynomolgus monkeys morphometrically.

Animals↗
PubMedDate not supplied

Fat patterning in athletes in relation to ethnic origin and sport.

Six skinfold measurements of 92 White, Black and Mexican-American high school varsity female athletes were analysed to identify principal components of fatness and relative fat patterning. As in other athletic and non-athletic samples, two principal components were evident: a first component, accounting for 69% of the variation, was positively related to all skinfold sites, and a second principal component, accounting for 11% of the variation, was correlated positively with extremity sites (particularly lower limb sites) and negatively with trunk sites. The first component (fatness) was significantly related to sport (P less than 0.02) but not ethnicity. The second component (extremity/trunk) was significantly related to ethnicity (P less than 0.01) but not sport. These results, although tentative due to the limited sample size, support our earlier findings on Olympic athletes, i.e., fatness is more influenced by sport and by training than is fat patterning.

Adipose Tissue↗