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PubMed2004

Application of multiway ICA for on-line process monitoring of a sequencing batch reactor.

Multiway principal component analysis has been shown to be a powerful monitoring tool in many industrial batch processes. However, it has the shortcomings that all batch lengths should be equal, the measurement variables must be normally distributed and that future values of the current batch must be estimated to allow on-line monitoring. In this work, it is shown that multiway independent component analysis (MICA) can be used to overcome these drawbacks and obtain better monitoring performance. The on-line MICA monitoring of batch processes is based on a new unfolding method and independent component analysis (ICA). ICA provides better monitoring performance than PCA in cases with non-Gaussian data because it is not based on the assumption that the latent variables are normally distributed. The MICA algorithm does not require any estimation of future batch values and can also be applied to non-equal batch length data sets. This article describes the application of on-line MICA monitoring of a sequencing batch reactor (SBR). It is successfully applied to an 80L SBR for biological wastewater treatment, which is characterized by a variety of disturbance sources with non-Gaussian characteristics. The SBR poses an interesting challenge from the point of process monitoring characterized by non-stationary, batchwise, multiscale, and non-Gaussian characteristics. The results of the bench-scale SBR monitoring clearly showed the power and advantages of MICA monitoring in comparison to conventional monitoring methods.

Automation↗

PubMedDate not supplied

Comparison of ethanol concentrations in blood, serum, and blood cells for forensic application.

Ethanol concentrations in serum (SAC) and whole blood (BAC) were determined for 235 subjects by a headspace gas chromatographic method. The SAC:BAC ratios ranged between 1.04 and 1.26. The mean was 1.14, and the normal distribution had a standard deviation (SD) of 0.041. When a conversion (division) factor for SAC to BAC of 1.18 (mean + 1 SD) was used, 84% of estimated BACs were less than that measured; the remaining estimates differed by less than 7 mg/dL. An SAC greater than 100 mg/dL reliably indicated a BAC of more than 80 mg/dL. Ethanol concentrations in blood cells (CAC) were similarly determined for 167 of these subjects. The CAC:BAC ratios ranged from 0.66 to 1.00 and had a mean of 0.865 and a negatively skewed normal distribution with an SD of 0.065. When a conversion (division) factor for CAC to BAC of 0.93 (mean + 1 SD) was used, 89% of estimated BACs were less than that measured; the remaining estimates differed by less than 8 mg/dL. A CAC greater than 80 mg/dL reliably indicated a BAC of more than 80 mg/dL. The CAC is useful in forensic practice when either blood or serum is not available.

Alcohol Drinking↗

PubMed1979

Pollution-induced changes in populations.

The effects of pollution by organic matter, oil or industrial waste on marine communities are remarkably similar. Diversity values fall, biomass and numbers of organisms initially rise and then fall as the pollution load is increased. Diversity indices are, however, insensitive to pollution-induced changes and have to be assessed subjectively. Departure from a log-normal distribution of individuals among species offers a sensitive and objective method of assessing perturbation effects on communities. Under severe pollution stress, the dominant species are those which have a flexible life-history ranging from direct development to a planktonic larva and the ability to undergo short-term genetic selection. Species have a somewhat less flexible life-history strategy show increased abundance under conditions of slight pollution. The increase in abundance of seven or eight neither rare nor common species, which gives the departure from a log-normal distribution, is suggested as being the most significant and the earliest detectable change caused by pollution in a community. Thus the presence of a species in a polluted area may be more a question of life-history strategy than the tolerance of adverse environmental conditions. If this hypothesis is correct, considerable doubt must beplaced on the ecological relevance of data from toxicity tests.

Animals↗

PubMed2000

[Biometry 2000. Fetal growth charts by the French College of fetal ultrasonography and the Inserm U 155].

OBJECTIVE: The aim of Biometry 2000 was to establish reliable sonographic fetal auxology reference charts for biparietal diameter, head circumference, abdominal diameter, abdominal circumference and femur length. DESIGN: A prospective multicentric longitudinal and transversal study was carried out. SUBJECTS: The data of this study were obtained from 35,456 scans recorded in 10,043 women for a period of one year. METHODS: Sonographic measurements were performed using a single method for each parameter. Twins and unknown gestational ages were not included. No exclusions were made for small-for-age, congenital malformations or any event during pregnancy. Assuming measurements have a normal distribution, centiles were calculated after polynomial regression models from mean and standard deviation according to gestational age in exact weeks from last menstrual period. RESULTS: A total of 32,584 fetal biparietal diameters, 20,400 direct cephalic circumferences, 31,790 transverse abdominal diameters, 21,562 direct abdominal circumferences and 30,960 femur lengths were obtained. Fetal growth charts with means, standard deviations and centiles are presented. CONCLUSION: The multicentric study, Biometry 2000, has established sonographic fetal charts derived from a large sample of scans and unselected pregnant women assuming a normal distribution.

Abdomen↗

PubMedDate not supplied

Plasma concentrations of urea and creatinine in primary school children in Ujung Pandang.

A study of plasma concentrations of urea creatinine in 202 primary school children aged between 6 to 15 years was carried out in Ujung Pandang from November 1, 1988 through February 28, 1989. Sampling was done using multi-stage random sampling method. Plasma urea concentrations were not affected by sex, age and nutritional status. Normal distribution of plasma urea concentrations in P2.5 and P97.5 were 8.13 mg/dl and 24.09 mg/dl respectively (95% confidence level). There was no difference of creatinine concentration between the two sexes. The overall mean creatinine concentrations was significantly higher in the well-nourished group (0.73 +/- 0.081) mg/dl) as compared to PEM group (0.63 +/- 0.066 mg/dl). This study revealed a correlation between age and plasma creatinine concentrations in the well-nourished (r = 0.46, p less than 0.01) as well as in PEM (r = 0.37, p less than 0.01) group. Hence, normal distribution of plasma creatinine concentrations should be base on values in each age group. This study showed no correlation between plasma urea and creatinine concentrations.

Adolescent↗

PubMed2003

Testing the utility of a geographical profiling approach in three rape series of a single offender: a case study.

The purpose of the study was to test the potential utility of a geographical profiling approach for three separate series of rapes committed by a single offender. Two different mathematical distance-decay functions using either a normal distribution with a mean distance and standard deviation based on previous research or a truncated negative exponential function based on distances between crime sites in the series under investigation were applied to each of the series giving prioritised search areas the accuracy of which was then assessed. The prioritised area that had to be searched before the home base of the offender could be located varied from 7.60 km(2) or 2.15% of the total search area at its best to 15 1.10 km(2) or 42.66% at its worst for the normal distribution based on previous research and from 42.06 km(2) or 11.88% to no improvement when the truncated negative exponential function was used. The functions used showed less predictive ability when the offender was a commuter. Explanations for the variations in the findings as well as suggestions for improvements were outlined in the discussion.

Forecasting↗

PubMed1997

Rett syndrome: an analysis using Sartwell's incubation period model.

Evidence suggests that Rett syndrome is a genetic disorder; however, an etiologic genetic model has yet to be identified. The purpose of this study was to apply a statistical model, Sartwell's incubation period model, to estimate the incubation period of Rett syndrome and postulate further on the etiology of Rett syndrome. Sartwell's model was used to test the hypothesis that the age of onset of developmental regression distributions approximate a logarithmic normal model and thus the etiologic factors of Rett syndrome occur in utero or prior to conception. Data from three case-series of Rett syndrome from different geographic regions were used for the analyses. Curves resulting from the analyses demonstrated a good approximation to the logarithmic normal distribution, indicating a good fit of the data to Sartwell's model. In conclusion, the incubation period of Rett syndrome fits the logarithmic normal model, which is consistent with the theory that a major causal factor for Rett syndrome most likely occurs in utero or prior to conception, eg, a defective gene.

Age of Onset↗

PubMed1987

Human brain D1 and D2 dopamine receptors in schizophrenia, Alzheimer's, Parkinson's, and Huntington's diseases.

Because dopamine D2 receptors are known to be elevated in schizophrenic brain striata, this study examined whether a similar dopamine receptor elevation occurred in other diseases including neuroleptic-treated Alzheimer's and Huntington's diseases. The average D1 density in postmortem striata from Alzheimer's patients was 17.6 +/- 0.1 pmol/g, similar to an age-matched control density of 16.6 +/- 0.4 pmol/g. The average D1 density in schizophrenia patients was 19.0 +/- 0.6 pmol/g, similar to the age-matched control density of 17.9 +/- 0.6 pmol/g. In Parkinson's disease patients, however, the D1 receptor density was elevated, with values of 22.8 +/- 1.2 pmol/g (in patients not receiving L-DOPA) and 19.6 +/- 1.5 pmol/g (in patients receiving L-DOPA) compared to the age-matched control density of 16.0 +/- 0.4 pmol/g. The D2 receptors in Alzheimer's striata averaged 13.4 +/- 0.6 pmol/g (in patients who had not received neuroleptics), almost identical to the control density of 12.7 +/- 0.3 pmol/g. The average D2 density in neuroleptic-treated Alzheimer's striata was 16.7 +/- 0.7 pmol/g, an elevation of 31%, the individual values of which had a normal distribution. In Parkinson's disease patients, the D2 densities were elevated in tissues from patients not receiving L-DOPA (19.9 +/- 1.5 pmol/g in putamen and 14.8 +/- 1.2 pmol/g in striatum) compared to the age-matched control values of 13.0 +/- 0.4 pmol/g and 12.6 +/- 0.3 pmol/g, respectively. In Huntington's disease patients, the D2 density averaged 7.5 +/- 0.4 pmol/g in patients who had not received neuroleptics, but was 10.3 +/- 0.6 pmol/g in those who had. Although all of the D1 and D2 densities in each of the above diseases and subgroups revealed a normal distribution pattern, the D2 densities in schizophrenia displayed a bimodal distribution pattern, with 48 striata having a mode at 14 pmol/g, and the other 44 striata having a mode at 26 pmol/g. Thus, compared to the neuroleptic-induced and unimodal elevations in D2 of 31% in Alzheimer's disease and 37% in Huntington's disease, the schizophrenic striata with a mode of 26 pmol/g (105% above control) appear to contain more D2 receptors than can be accounted for by the neuroleptic administration alone.

Adult↗

PubMed1982

An immunoperoxidase study of S-100 protein distribution in normal and neoplastic tissues.

The presence of S-100 protein was immunohistochemically studied in many types of formalin-fixed and paraffin-embedded tumors (260 cases). Peripheral nerve tumors, i.e., schwannomas, neurofibromas, granular cell tumors, and neurogenic sarcomas were demonstrated to contain variable amounts of S-100 protein in the tumor cell cytoplasm and nuclei. In ganglioneuromas and ganglioneuroblastomas, neoplastic Schwann cells or satellite cells were positive for S-100 protein. About one-half of the cases of carcinoid tumors stained weakly for S-100 protein. In addition to these nervous tissue and carcinoid tumors, chondrosarcoma, chordomas, pleomorphic adenomas of the salivary gland, and Langerhans cell granulomatosis were also shown to produce S-100 protein. In many types of breast tumors and other lesions, S-100 protein positive cells were likely to correspond to the distribution of myoepithelial cells. These results indicate that S-100 protein is not strictly specific to nervous tissue and its tumors; however, the immunohistochemical demonstration of S-100 protein can be a useful diagnostic tool in tumor diagnosis.

Breast Diseases↗

PubMed2003

Autoantibodies to thyroperoxidase (TPOAb) in a large population of euthyroid subjects: implications for the definition of TPOAb reference intervals.

OBJECTIVE: Measurement of autoantibodies against thyroperoxidase (TPOAb) plays an important role in the diagnosis of autoimmune thyroid disease. The assessment of reference intervals for TPOAb, however, is a controversial issue since elevated TPOAb values are sometimes found in subjects without other evidence of thyroid disease. METHODS: TPOAb were measured in 1,295 euthyroid individuals using a highly sensitive, fully automated chemiluminescence assay (Advantage A-TPO, Nichols Institute Diagnostics, CA, USA). The study subjects participated in a population study on the prevalence of thyroid disorders in the German federal state of Saxony, an area of mild iodine deficiency. RESULTS: TPOAb above the detection limit of 0.45 IU/ml were found in 1,277/1,295 euthyroid individuals. TPOAb values in the low measurable range below 1.1 IU/ml followed a normal distribution, and this was independent of age and sex. When using a cut-off value of 1.1 IU/ml, which corresponds to a sensitivity of 79% and a specificity of 95% resulting from the receiver-operator characteristic plot for discrimination between a main type and other types with a higher mean value of TPOAb, elevated TPOAb were found in 14.4% of euthyroid men and in 25.8% of euthyroid women. CONCLUSIONS: The results demonstrate for the first time that TPOAb are detectable in nearly all euthyroid individuals and that TPOAb values in the low measurable range are normally distributed. The distribution of TPOAb values in the low range is independent of age and sex. Based on these data, reference intervals for TPOAb can be defined that are independent of the population investigated. The clinical significance of slightly elevated TPOAb, however, has still to be defined by prospective studies.

Adult↗

PubMedDate not supplied

Modelling the associations of BMI physical activity and diet with arterial blood pressure: some results from the Allied Dunbar National Fitness Survey.

In order to identify risk factors (e.g. physical inactivity, dietary composition) associated with blood pressure within a given population, it is necessary to adjust for differences in known associations (e.g. age, body weight) using a method such as the analysis of covariance. However, the blood pressure results from the Allied Dunbar National Fitness Survey (ADNFS) were found to be non-linear with age, positively skewed (with heteroscedastic errors) and therefore non-normally distributed. Hence, before valid inferences can be drawn from such data, there is a clear need to formulate an appropriate model for blood pressure that will overcome these undesirable characteristics. A multiplicative model (with allometric body size components) was proposed and fitted to the ADNFS blood pressure results. After a logarithmic transformation the parsimonious solution was able to confirm the association with BMI, the non-linear changes with age, and overcome the heteroscedastic and positively skewed errors, i.e. the residuals from the fitted log-linear models for both systolic and diastolic blood pressure were symmetric and normally distributed. Other factors were found to make a significant additional contribution to the prediction of blood pressure. Cyclists, participants in vigorous physical activity and those subjects who consumed more fresh fruit, rice or pasta, and wine were found to have significantly lower mean levels of blood pressure. Indeed, the gap in blood pressure between participants and non-participants in vigorous physical activity increased further with age. However, subjects who drank more beer tended to have significantly higher mean levels of blood pressure. Thus by developing an appropriate model for arterial blood pressure, some well known, and some less well known, associations with arterial blood pressure have been identified. The results suggest that physical activity and other lifestyle factors may protect against hypertension.

Adipose Tissue↗

PubMed2005

Niche overlap estimates based on quantitative functional traits: a new family of non-parametric indices.

The concept of niche overlap appears in studies of the mechanisms of the maintenance of species diversity, in searches for assembly rules, and in estimation of within-community species redundancy. For plant traits measured on a continuous scale, existing indices are inadequate because they split the scale into a number of categories thus losing information. An index is easy to construct if we assume a normal distribution for each trait within a species, but this assumption is rarely true. We extend and apply an index, NO(K), which is based on kernel density functions, and can therefore work with distributions of any shape without prior assumptions. For cases where the ecologist wishes to downweight traits that are inter-correlated, we offer a variant that does this: NO(Kw). From either of these indices, an index of the mean niche overlap in a community can be calculated: NO(K,community) and NO(Kw,community). For all these indices, the variance can be calculated and formulae for this are given. To give examples of the new indices in use, we apply them to a coastal fish dataset and a sand-dune plant dataset. The former exhibits considerable non-normality, emphasising the need for kernel-based indices. Accordingly, there was a considerable difference in index values, with those for an index based on a normal distribution being significantly higher than those from an index which, being based on kernel fitting, is not biased by an assumption for the distribution. The NO(K) values were ecologically consistent for the fish species concerned, varying from 0.02 to 0.53. The sand-dune plant data also showed a wide range of overlap values. Interestingly, the least overlap was between two graminoids, which would have been placed in the same functional group in the coarse classification often used in functional-type/ecosystem-function work.

Animals↗

PubMed2005

Metal contents in the groundwater of Sahebgunj district, Jharkhand, India, with special reference to arsenic.

A detailed study has been presented on groundwater metal contents of Sahebgunj district in the state of Jharkhand, India with special reference to arsenic. Both tubewell and well waters have been studied separately with greater emphasis on tubewell waters. Groundwaters of all the nine blocks of Sahebgunj district have been surveyed for iron, manganese, calcium, magnesium, copper and zinc in addition to arsenic. Normal distribution statistic, exploratory data analysis and robust Z-score analysis have been employed to find out the distribution pattern, localisation of data, outliers and other related information. Groundwaters of three blocks of Sahebgunj, namely, Sahebgunj, Rajmahal and Udhawa have been found to be alarmingly contaminated with arsenic present at or above 10 ppb. Arsenic distribution patterns in these blocks are highly asymmetric in nature with the common feature of increasing width from first to fourth quartile. A very broad fourth quartile in each case represents a long asymmetric tail on the right of the median. Tubewell waters of at least two more blocks require regular monitoring to identify the outbreak of arsenic at the onset. Groundwaters of Sahebgunj district in general contain high iron and manganese. It is by and large soft in nature. Well waters have been found to be better with regard to arsenic but iron and manganese contents do not vary significantly. Normal distribution analysis (NDA), box and whisker (BW) plot and Z-score analysis together can provide a reasonably complete statistical picture of metal contents in Sahebgunj district groundwaters.

Arsenic↗

PubMed2004

An ROC comparison of four methods of combining information from multiple images of the same patient.

Variance of diagnostic information contained in an image degrades diagnostic accuracy. Acquiring multiple images of the same patient (e.g., mediolateral oblique and craniocaudal view mammograms) can, in principle, help reduce this degradation. We demonstrate how this can be accomplished in the context of computer-aided diagnosis (CAD). Assuming that computer outputs obtained from multiple images of the same patient can be transformed monotonically to the same pair of truth-conditional normal distributions and, for simplicity, ignoring correlation among images, we investigate theoretically four methods of combining the computer outputs: taking the average, the median, the maximum, or the minimum. We found, as one would expect, that both the average and the median always produce an improved area under the receiver operating characteristic (ROC) curve (AUC) compared to the single-view images, while the average always produces better performance than the median. However, the maximum and minimum also can produce improved AUCs in some situations, and under certain conditions can outperform the average. Surprisingly, we found that the maximum and minimum of normally-distributed decision variables produce nearly binormal ROC curves. These results can be used as a guide in attempting to increase the efficacy of CAD when multiple images are available from the same patient.

Algorithms↗

PubMedDate not supplied

[Human lactoferrin: isolation of highly purified preparations from human milk, various physico-chemical properties and distribution in normal and tumor tissues].

Two procedures for isolation of lactoferrin are described using ion exchange and immunoaffinity chromatography. Electrophoretic mobility, molecular mass, isoelectric point and other physico-chemical properties of the antigen were studied. Immunodiffusion and immunoperoxidase techniques exhibited presence of the antigen in some tissues containing glandular epithelium as well as a decrease in lactoferrin content in malignization.

Chromatography, Affinity↗

PubMed1990

[Phenotypic changes in the mononuclear cells of patients with primary immunodeficiencies].

The study of differentiation antigens of circulating mononuclear cells in 70 patients with primary immunodeficiency (PID) using monoclonal antibodies allowed us to define phenotypic profiles that are characteristic of the different described syndromes. In common variable immunodeficiency we found percentages of lymphocytes within normal ranges, and an altered CD4/CD8 ratio. In sex-linked agammaglobulinemia, absence of B lymphocytes with normal distribution of regulatory populations (CD4/CD8) were found. These results allow us to distinguish two clinically and infectologically similar conditions. In selective IgA deficiency, distribution of lymphocytic populations was normal. In immunodeficiency with hyper IgM, considered up to date as an abnormal maturation of B lymphocytes, we observed a deficiency in cellular immune response, and a phenotypic profile characterized by: decreased number of CD3 cells, inverted CD4/CD8 ratio, and increased CD38 population; this profile being similar to the one that we found in predominantly cellular immunodeficiency. In predominantly cell-mediated immunodeficiency and in those immunodeficiencies associated to other defects (such as: hyper IgE syndrome, Di George syndrome), the most important finding was a significative increase in CD38 population. Although it's not possible to consider on this basis that there is a defect at the thymic level of T-cells maturation, the high levels of circulating CD38 cells were a clear indication of altered cellular immune response in our series of patients. Patients with predominantly cell-mediated immunodeficiency showed the lowest levels of CD4 cells and the corresponding inversion of CD4/CD8 ratio. In Di George syndrome we found a markedly diminished CD8 population that differentiates this entity from the rest of the studied syndromes. In chronic mucocutaneous candidosis distribution of lymphocytic populations was normal, but a significative increase in the percentages of CD11b+ cells was observed. In patients with antibodies deficiency that received substitutive treatment with gammaglobulin we found no variations in lymphocytic populations distribution. In the group of patients with altered cellular immunity treated with thymic hormones, observed phenotypic changes (increase in T-cells population, trend to normalization in CD4/CD8 ratio, and decrease in CD38 population) were transient, and lasted only during the treatment period. We considered that describing these phenotypic profiles is a useful diagnosis tool when evaluating patients with PID, since these profiles are characteristic and very stable.

Adult↗

PubMed2004

Comparative analysis of NK cell subset distribution in normal and lymphoproliferative disease of granular lymphocyte conditions.

We have characterized the heterogeneity of human blood NK cell subsets defined by expression of KIR, lectin like receptors and NK cell differentiation markers within a cohort of 51 healthy Caucasian individuals. High inter-individual variability in cell surface expression of most NK cell markers is observed. Range values defining NK cell subsets in healthy donors were further used as references to characterize 14 patients with NK-type lymphoproliferative disease of granular lymphocytes (NK-LDGL). Alterations of the KIR repertoire were noted in all NK-LDGL patients. NK cell expansions were classified as oligoclonal KIR(+) or as non-detectable KIR ((nd)KIR) using anti-KIR2DL1/2DS1, anti-KIR2DL2/2DL3/2DS2, anti-KIR3DL1 and anti-KIR2DS4 monoclonal antibodies. A major reduction in the size of the CD56(bright) NK cell subset was a constant feature of NK-LDGL. Altered distribution of CD94(+), CD161(+), and CD162R(+) NK cell subsets was also observed in NK-LDGL patients. Considering the potential role of NK cells in eliminating tumors or virus-infected cells, the reference values defined in this study should be valuable to characterize both quantitative and qualitative alterations of the NK cell repertoire in pathological conditions and to monitor NK cell reconstitution following hematopoietic transplantation.

Adolescent↗

PubMed2002

Radiation dose distributions in normal tissue adjacent to tumors containing (131)I or (90)Y: the potential for toxicity.

UNLABELLED: Given the relatively large tumor-absorbed doses reported for patients receiving radionuclide therapy, particularly radioimmunotherapy, and the relatively long pathlength of the nonpenetrating emissions of some radionuclides being used for these therapies, there exists the possibility of large absorbed doses to tissues adjacent to, surrounded by, or surrounding these tumors. Because tumors can occur adjacent to critical organs or tissues, such as arteries, nerves, pericardium, and the walls of the organs of the gastrointestinal tract, large absorbed doses to these normal tissues can lead to acute complications. METHODS: In this study, the Monte Carlo radiation transport code MCNP4b was used to simulate the deposition of energy from emissions of 2 radionuclides of interest, (131)I and (90)Y, to assess the possible magnitude of the absorbed doses in tissues adjacent to tumors. Mathematic models were constructed to simulate situations that might occur, such as tumor wrapped around a small cylinder (e.g., a nerve or artery), tumor against a tissue (e.g., the pericardium or wall of any gastrointestinal tract organ), and tumor surrounded by any soft tissue. Tumor masses of 10, 20, and 40 g were used in each model. Depth dose distributions were calculated using Monte Carlo simulations of the radiation transport in these geometric models. RESULTS: For tissues close to tumors containing (90)Y, the absorbed dose ranged from 24% of the absorbed dose in the tumor, for the case of tissues 1 mm from the tumor, to 103% of the absorbed dose in the tumor, for the case of small structures such as nerves or arteries surrounded by tumor. For tissues close to tumors containing (131)I, the absorbed dose ranged from 4% of the absorbed dose in the tumor, for the case of tissues 1 mm from the tumor, to 46% of the absorbed dose in the tumor, for the case of small structures such as nerves or arteries surrounded by tumor. CONCLUSION: This study showed that when absorbed doses to tumors are large, the absorbed dose to adjacent tissues can also be large, potentially causing unexpected toxicities.

Computer Simulation↗