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PubMed2006

Qualitative identification of tea categories by near infrared spectroscopy and support vector machine.

Near-infrared (NIR) spectroscopy has been successfully utilized for the rapid identification of green, black and Oolong tea. The spectral features of each tea category are reasonably differentiated in the NIR region, and the spectral differences provided enough qualitative spectral information for the identification of tea. Support vector machine (SVM) as the pattern recognition was applied to identify three tea categories in this study. The top five principal components (PCs) were extracted as the input of SVM classifiers by principal component analysis (PCA). The RBF SVM classifiers and the polynomial SVM classifiers were studied comparatively in this experiment. The best experimental results were obtained using the radial basis function (RBF) SVM classifier with sigma=0.5. The accuracies of identification were all more than 90% for three tea categories. Finally, compared with the back propagation artificial neural network (BP-ANN) approach, SVM algorithm showed its excellent generalization for identification results. The overall results show that NIR spectroscopy combined with SVM can be efficiently utilized for rapid and simple identification of the tea categories.

Pattern Recognition, Automated↗
PubMed2003

A method for monitoring the surface conservation of wooden objects by Raman spectroscopy and multivariate control charts.

The principles of quality control and multivariate statistical analysis were applied to the monitoring of the conservation state of wooden works of art. Three degradation processes (exposure to a wet atmosphere, to an acidic attack, and to UV light) were simulated on the surface of wooden boards of the XVI century and were monitored by the use of Raman spectroscopy. The resulting spectra were treated by principal component analysis, which allowed reduction of the system dimensionality. The relevant principal components were used to build multivariate control charts, namely, the Shewhart, CUSUM, and SMART (simultaneous scores monitoring and residual tracking) control charts. The Shewhart charts allowed identification of the effects due to the degradation processes. The CUSUM charts permitted identifcation of the exact moment in which the degradation treatment was started. The SMART charts provided a synthetic description of the conservation state of the wooden surface by means of only two charts: the T2 Hotelling and the DModX charts.

Journal Article↗
PubMed1999

Influence of partial replacement of NaCl with KCl and CaCl(2) on texture and color of dry fermented sausages.

A Spanish type of dry fermented sausage, Chorizo de Pamplona, was manufactured with a mixture of (2.29%) different salts (NaCl, KCl, and CaCl(2)) with an equivalent ionic strength to that of the control manufactured with 2.6% NaCl. The use of this salt mixture affected the texture profile analysis (TPA), giving rise to a significant reduction in hardness, cohesiveness, gumminess and chewiness. Instrumental color values showed higher b (yellowness) and L (lightness) values. Sensory texture and color intensity yielded lower scores, but they were classified as acceptable. Principal component analysis was carried out with the instrumental measures. The two principal components explained 76.9% of the variance. Modified and control samples were separated by the first component, which explained 57.1% of the variance and was defined basically by texture parameters.

Animals↗
PubMed2004

Modulation of binding strength in several classes of active site inhibitors of acetylcholinesterase studied by comparative binding energy analysis.

The comparative binding energy (COMBINE) methodology has been used to identify the key residues that modulate the inhibitory potencies of three structurally different classes of acetylcholinesterase inhibitors (tacrines, huprines, and dihydroquinazolines) targeting the catalytic active site of this enzyme. The extended set of energy descriptors and the partial least-squares methodology used by COMBINE analysis on a unique training set containing all the compounds yielded an interpretable model that was able to fit and predict the activities of the whole series of inhibitors reasonably well (r2 = 0.91 and q2 = 0.76, 4 principal components). A more robust model (q2 = 0.81 and SDEP = 0.25, 3 principal components) was obtained when the same chemometric analysis was applied to the huprines set alone, but the method was unable to provide predictive models for the other two families when they were treated separately from the rest. This finding appears to indicate that the enrichment in chemical information brought about by the inclusion of different classes of compounds into a single training set can be beneficial when an internally consistent set of pharmacological data can be derived. The COMBINE model was externally validated when it was shown to predict the activity of an additional set of compounds that were not employed in model construction. Remarkably, the differences in inhibitory potency within the whole series were found to be finely tuned by the electrostatic contribution to the desolvation of the binding site and a network of secondary interactions established between the inhibitor and several protein residues that are distinct from those directly involved in the anchoring of the ligand. This information can now be used to advantage in the design of more potent inhibitors.

Algorithms↗
PubMed1977

Physical and behavioral aspects of sexual maturation in male golden hamsters.

Male golden hamsters (Mesocricetus auratus) were examined from 3 to 9 wk of age for morphological, physiological, and behavioral indices of sexual maturation. Although each of the eight variables selected for measurement displayed a unique developmental profile, a principal-components analysis of these variables resulted in the extraction of two principal components, one tentatively labeled physical and gross behavioral maturation (accounting for 66% of the total variance) and the other designated perfection of mounting orientation (accounting for an additional 12% of the variance). This result indicates that puberty in the male hamster is best viewed as two independent processes, rather than as a unitary process, or as an arbitrary term applied to a variety of unrelated developmental phenomena. Advantages of using multi-variate composite scores and selected univariate measurements are discussed; as are methods of comparing developmental changes in different variables. A second experiment confirmed an unexpectedly early onset of androgen secretion and an unusual pattern of body weight gain.

Age Factors↗
PubMed2006

Trichophyton species: use of volatile fingerprints for rapid identification and discrimination.

BACKGROUND: Fungal infection of the skin is a common clinical problem, and laboratory confirmation of the diagnosis is important to ensure appropriate treatment. The identification of the species of fungus is also important, because different fungal species have different modes of transmission, and this may be of importance both in preventing re-infection and in avoidance of infection of others. OBJECTIVES: This study examined the potential of using volatile production patterns for the detection and discrimination between four Trichophyton species (T. mentagrophytes, T. rubrum, T. verrucosum and T. violaceum) in vitro on solid media and in broth culture. METHODS: Two different sensor array systems (conducting polymer and metal oxide sensors) were examined for comparing the qualitative volatile fingerprints produced in the headspace by these species over periods of 24-120 h. The relative sensitivity of detection of two of the species (T. mentagrophytes, T. rubrum) was determined for log 1 to log 7 inoculum levels over the same time period. RESULTS: The conducting polymer-based system was unable to differentiate between species based on volatile fingerprints over the experimental period. However, metal oxide-based sensor arrays were found to be able to differentiate between the four species within 96 h of growth using principal component analysis which accounted for approximately 94% of the data in principal components 1 and 2 based on the qualitative volatile production patterns. This differentiation was confirmed by cluster analysis of the data using Euclidean distance and Ward's linkage. Studies of the sensitivity of detection showed that for T. mentagrophytes and T. rubrum it was possible to differentiate between log 3, log 5 and log 7 inoculum levels within 96 h. CONCLUSIONS: This is the first detailed study of the use of qualitative volatile fingerprints for identification and discrimination of dermatophytes. This approach could have potential for rapid identification of patient samples, reducing significantly the time to treatment.

Biosensing Techniques↗
PubMed1998

Risk estimates for dichotomous genetic disease traits based on a cohort study of relatedness in purebred dog populations.

As a result of strong selection in closed gene pools, dog breeds represent populations of highly related animals. Prominent founder-effects are responsible for inherited diseases occurring in particular breeds, and each breed may have several breed-related diseases, often with a high incidence. Such inherited diseases are a major problem in purebred dog populations, and probably threaten their survival. On the basis of pedigree information held by the National Kennel Clubs and reliable medical data of a representative longitudinal cohort, estimates have been made of the relative risks of dichotomous disease traits in all combined breeding stock. This approach is independent of assumptions about modes of inheritance or thresholds. In a cohort study, all the common ancestors of the cases are selected and their degree of relatedness to both cases and controls is estimated. The ancestors which are positively associated with the dichotomous disease trait are selected on the basis of scores of relatedness. To reduce the number of parameters, while maintaining maximal informativeness, a principal component analysis is applied. Finally a logistic model, based on the principal components and the case control definitions, describes the most likely pattern of the passage of genetic risk factors down the generations. Estimates of relatedness to seven highly related ancestors were sufficient to describe the distribution of disease in a population of Dutch labrador retrievers. This approach may be used for genetic counselling for any clinical phenotypically dichotomous trait in such a highly related population of companion animals, and may also help to identify suitable dogs for molecular studies of the underlying defect.

Animals↗
PubMed1994

Symptom dimensions of the SCL-90-R: a test of the tripartite model of anxiety and depression.

To determine the extent to which the SCL-90-R assesses general distress or specific dimensions of psychopathology, two principal components analyses were conducted based on 900 outpatients diagnosed with mixed psychiatric disorders. The first component explained 30.5% of the total variance and was interpreted as reflecting overall symptom distress. Partialling the first component out of the correlations among the symptoms in a second principal components analysis, we found four specific residual components reflecting somatic anxiety, depression, irritability, and attention problems. The results were discussed as partially supporting Clark and Watson's (1991) tripartite model of anxiety and depression.

Adolescent↗
PubMed2005

Tetraphyllidean plerocercoids from Western Mediterranean cetaceans and other marine mammals around the world: a comprehensive morphological analysis.

Tetraphyllidean plerocercoids have occasionally been reported in marine mammals, but they have rarely been described in detail, and the ecological significance of these infections is unclear. We described plerocercoids collected from the mucosa of the terminal colon and rectum, the anal crypts, and the hepatopancreatic ducts of 7 striped dolphins Stenella coeruleoalba, 1 Cuvier's beaked whale Ziphius cavirostris, and 3 Risso's dolphins Grampus griseus from the Spanish Mediterranean. We also examined undescribed plerocercoids from 3 cetacean species from the Atlantic and the Pacific. All plerocercoids had a lanceolate body, and a scolex with an apical sucker and 4 sessile monolocular bothridia. The bothridia had free posterior edges and an accessory sucker at their anterior end. Under light microscopy, the bothridia of some Mediterranean specimens looked bilocular without accessory suckers, but a true accessory sucker was observed in histological sections. A principal component analysis revealed 2 stable clusters of specimens along the first principal component regardless of host species. These "large" and "small" morphotypes are thought to represent early migratory stages of Phyllobothrium delphini and Monorygma grimaldii. The similarity in scolex morphology, the observation of plerocercoids buried in intestinal regions close to the sites where M. grimaldii and P. delphini occur, and the coexistence of all larval forms in the same individual hosts would support this hypothesis. Future molecular analysis may confirm it.

Anal Canal↗
PubMed2004

Determination of protein concentration in raw milk by mid-infrared fourier transform infrared/attenuated total reflectance spectroscopy.

This study investigates the potential use of attenuated total reflectance spectroscopy in the mid-infrared range for determining protein concentration in raw cow milk. The determination of protein concentration is based on the characteristic absorbance of milk proteins, which includes 2 absorbance bands in the 1500 to 1700 cm(-1) range, known as the amide I and amide II bands, and absorbance in the 1060 to 1100 cm(-1) range, which is associated with phosphate groups covalently bound to casein proteins. To minimize the influence of the strong water band (centered around 1640 cm(-1)) that overlaps with the amide I and amide II bands, an optimized automatic procedure for accurate water subtraction was applied. Following water subtraction, the spectra were analyzed by 3 methods, namely simple band integration, partial least squares (PLS) and neural networks. For the neural network models, the spectra were first decomposed by principal component analysis (PCA), and the neural network inputs were the spectra principal components scores. In addition, the concentrations of 2 constituents expected to interact with the protein (i.e., fat and lactose) were also used as inputs. These approaches were tested with 235 spectra of standardized raw milk samples, corresponding to 26 protein concentrations in the 2.47 to 3.90% (weight per volume) range. The simple integration method led to very poor results, whereas PLS resulted in prediction errors of about 0.22% protein. The neural network approach led to prediction errors of 0.20% protein when based on PCA scores only, and 0.08% protein when lactose and fat concentrations were also included in the model. These results indicate the potential usefulness of Fourier transform infrared/attenuated total reflectance spectroscopy for rapid, possibly online, determination of protein concentration in raw milk.

Animals↗
PubMed2000

Disturbed functional brain interactions underlying deficient tactile object discrimination in Parkinson's disease.

Somatosensory discrimination of cuboid objects was studied in a group of healthy volunteers and patients with Parkinson's disease using regional cerebral blood flow (rCBF) measurements obtained with positron emission tomography (PET) and 15O labeled water [H2 15O]. A 6-[18F]-fluoro-L-dopa (FDOPA) PET scan demonstrated that the patients may be grouped into those with normal and those with abnormally lowA FDOPA uptake in the caudate nucleus. The categorical group comparisons revealed that task-induced rCBF increases were deficient in bilateral motor and sensory cortical areas in the Parkinson patients. Moreover, deficient rCBF increases were evident in the mesial and right dorsolateral prefrontal cortex for patients in a more advanced disease state, who showed low FDOPA uptake in the caudate nucleus. A principal component analysis (PCA), performed on the rCBF data, identified three patterns (principal components, PCs) that differentiated patients from normals. The first PC represented a right-hemisphere dominant, bilateral group of brain areas known to be involved in tactile exploration. A second PC reflected a cortical-subcortical pattern of functional interactions, comprising cortical areas important for working memory processes. The third group-differentiating PC revealed a pattern of functional interactions involving bilateral temporo-parieto-occipital association cortices, which was consistent with a hypothesized supramodal network necessary for object discrimination. In an additional subgroup analysis, greater expression of the third PC pattern predicted greater caudate FDOPA uptake in patients. Our neuroimaging data revealed a disturbance of distinct patterns of brain functional interactions related to the sensorimotor deficit in Parkinson's disease and to deficits of cognitive information processing deficits in the more advanced stage of Parkinson's disease.

Adult↗
PubMed2005

A short acculturation scale for Mexican-American populations.

Acculturation is important to examine variables that differentiate members of ethnic groups so that interventions can be appropriately targeted. By using a population-based sample of Mexican-origin adults, we sought to validate an acculturation scale for Mexican-American populations. The acculturation instrument included eight items adapted from the Acculturation Rating Scale for Mexican Americans (ARSMA). By using principal component analysis, we calculated eigenvalues for the eight items. The first principal component accounted for 66% of the variance. Language spoken most of the time, by itself, explained 62.4% of the variance of the full model, whereas birthplace, by itself, accounted for 74%. Slight increases in correlation values were observed beyond a four-item model that included language spoken most of the time, language thought, ethnic identity, and birthplace. Future studies should compare this scale with other multidimensional scales.

Acculturation↗
PubMed2005

Development and validation of questionnaire measuring attitudes towards sexual health among university students.

AIM: To develop a questionnaire on attitudes towards sexual health and validate it on a sample of medical and non-medical students and adult women. METHODS: For the purpose os constructing a Likert-type scale, four medical studentsgenerated 130 statements reflecting clearly positive or negative attitudes towards sexual health. The scale had five scoring points (1 - strongly disagree, 2 - disagree, 3 - undecided, 4 - agree, and 5 - strongly agree). We revised the items to ensure that all were clearly positive or clearly negative in their form, as well as straightforward in their meaning, leaving 100 items in the raw questionnaire, which was then applied to the convenience sample (total n=336) of female medical students (n=93), male medical students (n=75), female non-medical students (n=93) and adult working women with at least high-school education (n=75). After the administration of the questionnaire, we performed content examination, discriminant validation of the statements, and principal-components analysis. RESULTS: After discriminant validation of the statements and principal-components analysis limited to three factors, the final scale contained 50 items (20 positive and 30 negative), distributed in three subscales: "Personal sexual health care," "Principles of sexual behavior," and "Safe sex behavior." The Cronbach alpha of the whole scale was 0.910, indicating good internal consistency. When the scores of the final scale were analyzed for the study sample, all participants had positive attitude towards sexual health, with a mean score (+/-standard deviation) of 4.1+/-0.4 out of maximum 5. The same was true for all threee subscales. Female groups, regardless of their student status or age, did not differ in their attitude scores on the whole scale, as well as on any of the subscales. Male medical students had lower scores on the whole scale and all subscales than the female groups. CONCLUSIONS: It is posible to construct a reliable instrument to assess attitudes towards three important aspects of sexual health: personal sexual health care, sexual behavior, and safe sex behavior. Future studies with this instrument, on different populations and in different cultural and socio-economic settings, are needed to make generalized conclusions on sexual health attitudes and behavior.

Adult↗
PubMedDate not supplied

Growth of the body in early fetuses studied by multivariate analysis.

The growth of the body was studied in 30 human fetuses ranged from 10 to 22 weeks of gestation. The fetuses were fixed by immersion in 4 percent formaldehyde and the following dimensions were studied: a) lengths: arm, forearm, hand, thigh, leg, foot and crown-rump (sitting height), b) perimeters: head, thorax and abdomen. A covariance matrix was calculated from natural logarithms of all measurements. The relative growth of these measurement was computed by multivariate allometry using a principal components analysis (PCA). All characters were positively correlated with the first principal component which accounted for 94.65 per cent of the total variance. Considering the different measurements in the sequence of the increasing growth rates no one was considered to increase in isometric relationship. PCA showed that the following measurements grew with negative allometry: head perimeter, C-R length, thoracic perimeter, length of the forearm and abdominal perimeter. On the other hand, the following lengths grew with positive allometry: hand, foot, thigh, arm and leg. In conclusion, during the first two trimesters of prenatal life the growth of the body is allometrical. Limbs increase with greater growth rates than the perimeters of the body cavities.

Body Height↗
PubMed2005

Evaluation of the taste and smell of bottled nutritive drinks.

The purpose of this study was to evaluate the palatability of 15 bottled nutritive drinks, all commercially available in the Japanese market, using data from artificial taste and odor sensors. In gustatory sensation tests, well-trained healthy volunteers were asked to score the drinks in terms of palatability and of the four basic tastes. The results suggest that overall palatability is positively correlated with sourness intensity and fruitiness (R=0.82 and 0.86, respectively) and negatively correlated with bitterness intensity and the tasting of medicinal plants (R=-0.85 and -0.80, respectively). The sourness and bitterness intensity could be predicted by taste sensor and fruitiness could be predicted by odor sensor, respectively. By performing principal component analysis of the taste sensor data, the 15 drinks could be classified into four groups. The group classified as being predominantly sour had the highest palatability score, 3.8. By principal component analysis of odor sensor data, the drinks could also be classified into four groups and this time the group with a fruity flavor (smell) showed the highest palatability score, 3.4. In the combined analysis of both taste and odor data, products containing medicinal plants showed the lowest palatability. Finally, the combined usage of the taste and odor sensors gave rise to a three-group classification. Thus, not only the taste sensor but also the odor sensor may be useful in evaluating the palatability of bottled nutritive drinks.

Beverages↗
PubMed2003

Gaussian distributions on Lie groups and their application to statistical shape analysis.

The Gaussian distribution is the basis for many methods used in the statistical analysis of shape. One such method is principal component analysis, which has proven to be a powerful technique for describing the geometric variability of a population of objects. The Gaussian framework is well understood when the data being studied are elements of a Euclidean vector space. This is the case for geometric objects that are described by landmarks or dense collections of boundary points. We have been using medial representations, or m-reps, for modelling the geometry of anatomical objects. The medial parameters are not elements of a Euclidean space, and thus standard PCA is not applicable. In our previous work we have shown that the m-rep model parameters are instead elements of a Lie group. In this paper we develop the notion of a Gaussian distribution on this Lie group. We then derive the maximum likelihood estimates of the mean and the covariance of this distribution. Analogous to principal component analysis of covariance in Euclidean spaces, we define principal geodesic analysis on Lie groups for the study of anatomical variability in medially-defined objects. Results of applying this framework on a population of hippocampi in a schizophrenia study are presented.

Algorithms↗
PubMed2005

[Analysis and recognition of CD4 cell microscopic image].

This paper introduces the technology of recognizing CD4 cell by a computer, which successfully segments the objects from the background through image processing and analyses the four features including geometric features, optical density, color and texture features. The method based on Principal Component Analysis algorithm is used for feature extraction, and a Back Propagation neural network classifier is constructed, from which the CD4 cell can be well recognized. CD4 cell, image segmentation, feature analysis, Principal Component Analysis (PCA), Back Propagation (BP) neural network classifier is constructed, from which the CD4 cell can be well recognized.

Algorithms↗
PubMed2003

Depression in vascular dementia.

OBJECTIVE: To study the presence of different dimensions of depression in subjects with vascular dementia. BACKGROUND: After a stroke, cognitive, affective and behavioural disturbances are common. It has been suggested that the nature of affective symptomatology can help to differentiate organic from psychological depression. METHODS: Cognitive and affective symptoms were assessed in 78 stroke patients and a principal component analysis was performed on these symptoms. Also, a discriminant analysis was carried out to establish the contribution of different symptoms on the diagnosis 'depressive disorder' and 'dementia'. RESULTS: (1) Principal component analysis revealed three distinct sub-syndromes: one with predominantly mood symptoms, one with essentially psychomotor symptoms, and one with vegetative symptoms; (2) mood, psychomotor and vegetative symptoms were all independently and strongly related to a diagnosis of major depressive disorder according to DSM-III-R criteria; (3) the psychomotor factor was also firmly associated with dementia; and (4) discriminant analysis gave further support for our conclusion that some of the depressive features, in particular the psychomotor factor, are at least partly related to the organic brain damage from stroke. CONCLUSION: The results indicate that different dimensions of depression could be discerned in a group of stroke patients and that the symptom profile of depression in these patients can be affected by the presence of dementia.

Affect↗