bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Statistical Classification Technique to the Forecasting of Outcomes of Diseases
Authors: Khakhubia Ts. G. , Gvantseladze L. G. , Felker V. M. 
Published: May 2007

AbstractA probabilistic statistical model based on statistical classification is proposed for disease outcome forecasting. In particular, cardiac infarction outcome is forecasted and a table of the forecasting results is given. A conclusion of theoretical character is made about the preferable use of a non‐uniform band width in the construction of a general histogram for unknown distribution density estimation.
Estimation of Relative Risk Under Variable Multiple Matching
Authors: Ejigou A. 
Published: May 2007

AbstractWhen disease incidence is low, the odds ratio, which closely approximates relative risk, is estimated optimally in a closed form using a variable matching ratio in a retrospective design. The model also enables one to assess the homogeneity of the odds ratio from the same one matched sample. Analogous procedures are shown to hold for the prospective design.
Designing the Sample Size for Non‐parametric, Multivariate Tolerance Regions
Authors: Ackerwn H. , Abt K. 
Published: May 2007

AbstractIn supplementation of the work by ABT (1977, 1982) and ACKERMANN (1980, 1983) extensive ta.bles and approximite formulae are provided for the determination of the sample size for constructing “inner” and “outer” limits of non‐parametric multivariate tolerance regions.
Variants of the Varimax Rotation Method
Authors: Frankel E. 
Published: May 2007

AbstractIn the present paper we present an example proving that the Varimax rotation method commonly used in factor analysis (see H. F. KAISER, 1958) need not give a unique solution. We also show that changing the original algorithm more than one local maximum of the criterion “V” can be achieved. Hence the loadings of factors and practical interpretations of solutions are affected in this way.
Unconditional Tests of Hypotheses Concerning Relative Risk
Authors: Bennett B. M. 
Published: May 2007

AbstractThe problem of estimation of, and statistical tests for, the relative risk (=α) from samples in which there is matching on covariates have been discussed by various authors (Cox, 1970; MANTEL and HAENSZEL, 1959) using the approach of conditional variates. This paper discusses log LR (likelihood ratio) tests of hypotheses concerning α, as based on one or more sets of matched samples. ApproximateX2tests are also developed for the hypotheses concerning α. An example is presented which illustrates the proposed tests of significance (Table 1).
The Structure of Ellipsoidal Distributions I. Canonical Analysis
Authors: Jensen D. R. 
Published: May 2007

AbstractThis study is concerned with the structure of variables having ellipsoidal distributions. In Part I it is shown that many normal‐theory results in canonical analysis are exact for all ellipsoidal distributions under a specified model for sampling. In Part II similar conclusions are drawn regarding the use of principal components. These findings suggest using normal‐theory procedures in canonical and principal components analyses as approximate large‐sample procedures for distributions attracted to ellipsoidal stable laws.
The Negative Binomial Distribution of Orderkand Some of Its Properties
Authors: Philippou A. N. 
Published: May 2007

AbstractThe negative binomial distribution of orderkis introduced and briefly studied. First it is shown that it is a proper probability distribution. Then its probability generating function, mean and variance are derived. Finally it is shown that the number of trials until therthkth consecutive success (r≧ 1,k≧ 1) in independent trials with constant success probabilityp(0 <p< 1) is distributed as negative binomial distribution of orderk.The present paper generalizes results of SHANE (1973), PHILIPPOU and MUWAFI (1982), and PHILIPPOU, GEORGHIOU and PHILIPPOU (1982).
Characterizations of Continuous Binomial and Negative Binomial Mixtures
Authors: Papageorgiou H. 
Published: May 2007

AbstractCharacterizations are given for binomial (n, ϑ) and negative binomial (k, ϑ) mixtures in terms of the regression function of the mixing random variableYon the mixture variableX.In both casesYis the parameter ϑ and the mixing distribution is a continuous distribution on (0, 1) and on (0, ∞) respectively. Biological applications are indicated.
Estimates of a Treatment Effect Based on Censored Data Rank Tests
Authors: Rosenkranz G. 
Published: May 2007

AbstractLinear rank test statistics are applied to the problem of estimating a treatment effect if two sets of censored failure time data are compared and the distributions of the log‐failure times of the two samples are assumed to differ only in location. Rank tests for this accelerated failure time model are reviewed and Hodges‐Lehmann type estimates for the shift parameter are proposed. Properties of these estimates are investigated, computational aspects are discussed and an example is presented.
Randomization Modelling of the Crossover Experiment for Clinical Trials
Authors: Gomez‐Marin O. , McHugh R. B. 
Published: May 2007

AbstractThe two‐period cross‐over experiment for clinical trials has been examined by several writers following a Gaussian linear model approach. Some authors have expressed interest in the “derivation of the finite permutation model” and have pointed out that the randomization approach to modeling the two‐period cross‐over design “would highlight the importance of randomizing the subjects to the two groups as a basis for inference”. However, in the literature, there is no development of the randomization approach to this important design.In this paper, after a statement of the experimental design and formulation of the observation random variables of the finite population, two additive randomization models—one with residual effects, the other without—which are the analogues of Grizzle's Gaussian models, are derived. Statistical inference is developed for these randomization models and the results are compared with those of the corresponding Gaussian models. Also, exact inference based upon Fischer's approach is presented.
On the Estimation of the Population Mean with Known Coefficient of Variation
Authors: Upadhyaya L. N. , Singh H. P. 
Published: May 2007

AbstractFor the estimation of population mean a class of estimators has been proposed when the coefficient of variation is known and its efficiency is compared with the usual unbiased estimator and the estimators suggested by various researchers. The properties of the proposed class of estimators have been also discussed in the case of normal population.
A Lagrangian Gamma Distribution of the Second Kind
Authors: Rao B. Raja , Janardan K. G. , Schaeffer D. J. 
Published: May 2007

AbstractThe distribution of the time T for the occurrence of the rth event is derived in a linear function Poisson process, which belongs to a recently introduced family of distributions (JANARDAN and RAO, 1981), called Lagrangian distributions of the second kind (LD2). In analogy with the ordinary Poisson process, the distribution of the random variable T has been termed the Lagrangian Gamma distribution of the second kind (LG2); several of its properties and special cases are studied. The frequency function is graphed for some parameter values.
A Comparison of Tests for Marginal Homogeneity in Square Contingency Tables
Authors: Krauth J. 
Published: May 2007

AbstractSeveral asymptotic tests were proposed for testing the null hypothesis of marginal homogeneity in square contingency tables withrcategories. A simulation study was performed for comparing the power of four finite conservative conditional test procedures and of two asymptotic tests for twelve different contingency schemes for small sample sizes. While an asymptotic test proposed by STUART(1955) showed a rather satisfactory behaviour for moderate sample sizes, an asymptotic test proposed by BHAPKAR(1966) was quite anticonservative. With no a priori information the performance of (r‐ 1) simultaneous conditional binomial tests with a Bonferroni adjustment proved to be a quite efficient procedure. With assumptions about where to expect the deviations from the null hypothesis, other procedures favouring the larger or smaller conditional sample sizes, respectively, can have a great efficiency. The procedures are illustrated by means of a numerical example from clinical psychology.
Interactions in Contingency Table Analysis
Authors: Töwe J. , Bock J. , Kundt G. 
Published: May 2007

AbstractProceeding from Lancaster's definition of interactions between random variables, the authors set up a model for contingency tables of any dimension. Three‐dimensional contingency tables are used as an example to discuss first and second order interaction effects, and the conventional independence are expressed by hypotheses concerning interaction effects. The opinions of other authors regarding second order interaction effects are discussed.
A Note on Resolvable Incomplete‐Block Designs
Authors: Patterson H. D. , Williams E. R. , Paterson L. 
Published: May 2007

AbstractKHARE and FEDERER (1981) have proposed a method for constructing resolvable incomplete‐block designs with, they claim, higher efficiencies than those of the α‐designs described by PATTERSON and WILLIAMS (1976a). This claim is shown here to be unfounded. The best α‐designs have higher efficiencies than the Khare and Federer designs, and can be constructed straightforwardly using the concise table of generating arrays in PATTERSON, WILLIAMS and HUNTER (1978).
Estimation of Fixed and Random Effects in the Functional Nonlinear Errors‐in‐Variable Model
Authors: Johnson P. M. , Milliken G. A. 
Published: May 2007

AbstractConsider an experiment where a nonlinear continuous functional relationship exists betweenyandX.Assume that this relationship has been measured atnreplicated points ofXfrom each ofttreatments or populations. Assume further that theXare fixed unknown vectors and that the location parametervis either a fixed unknown vector or a vector of random variables. In the first case various linear hypotheses are to be tested aboutv, such as tests for main effects and interaction; in the second case, the mean and variance of the random variablevare to be estimated. A two‐step procedure based on asymptotic theory is presented to test hypotheses or develop estimates for the fixed effects or random effects functional errors‐in‐variable model. An example of a one‐way random effects model is given.
A Note on Successive Sampling Over Two Occasions
Authors: Sisodia B. V. S. 
Published: May 2007

AbstractIn this note, an attempt has been made to study the effect on MVLUE of a population mean on the second occasion in successive sampling when sample values of correlation and regression coefficients are used in it. It was found that increase in the MSE of derived biased estimator is of the orderq2ρ2which may be negligible till the proportion of unmatched units (q) and correlation coefficient (ρ) are quite small.
On the Estimation of Population Mean in Stratified Sampling
Authors: Kaur Parvinder 
Published: May 2007

AbstractWhen stratified random sampling is used for the estimation of population mean, use of ‘Combined ratio estimator’ is well known. Some improved estimators for population mean are proposed which are better than ‘Combined ratio estimator’ and some other well known existing ones, from the point of view of bias and mean square error. An empirical illustration is given.
Robustness of Sequential Tests for Means
Authors: Rasch D. 
Published: May 2007

AbstractThree sequential tests of the null hypothesis, μ = μ0, versus an alternative of the form (μ − μ0)2= =σ2d2 are compared for different forms of violation of the underlying normal assumption. 10000 samples were simulated for d=0.6; 1.0 and 1.6 (σ2 = 1), four (α, β)‐combinations and seven alternative distributions. The results show that for small d‐values one test is robust for α and another for β. For large d all tests can be used.
The Problem of Nucleolar Number in Cell Nuclei and in Sections of Cell Nuclei
Authors: Voss K. , Roth K. 
Published: May 2007

AbstractIn this paper the mean number N of nucleoli of cell nuclei and the relative frequency PN of cell nuclei with N nucleoli are investigated. To solve the first problem, the stereological model of convex shaped nuclei and nucleoli and the assumption of randomly‐isotropically distributed objects in space are used. The model is developed for non‐vanishing thickness T of tissue sections. The relationship between the unknown number N of nucleoli in cell nuclei and the mean number n of nucleoli in nuclear sections determined by counting is N = n (D+T)/(d + T). Here D and d are the mean values of caliper diameter for nuclei and for nucleoli, resp. The second problem is illustrated by means of some biomedical examples: The relative frequency PN of cell nuclei with N nucleoli can be approximated by a generalized Poisson distribution in all investigated cases. Therefore the mean nucleolar number N is the essential parameter to describe the frequencies of cell nuclei with different numbers of nucleoli.
The Power Function of the Test for ‘No Three Factor Interaction’ in 2×2×2 Contingency Tables
Authors: Haber M. 
Published: May 2007

AbstractThree approximations to the power function of the chi‐square test for the hypotheses of ‘no three factor interaction’ in a 2 × 2 × 2 contingency table are introduced and compared. The first method is based on the sampling distribution of the logarithm of the odds ratio, the second‐on the non‐central X2 distribution and the third—on the conditional distribution of a cell entry. The last method is found to provide the closest approximation under various alternative hypotheses and sample sizes.
Canonical Correlation as a Discriminant Tool in a Periodontal Problem
Authors: Lindsey H. , Webster J. T. , Halpern S. 
Published: May 2007

AbstractThis paper illustrates two advantages of using canonical correlation as a tool in the discriminant problem, with more than two populations, rather than the more familiar Anderson discriminant function. These advantages are: i) simultaneous test of significance as to whether the means of the populations differ and ii) given that the means differ, a graphic tool to illustrate the nature of the difference between the populations. If there are natural groupings of the populations, an analytic technique is also available to augment i). This latter property is also demonstrated in the accompanying application.
Development and validation of bioanalytical methods for imidafenacin (KRP‐197/ONO‐8025) and its metabolites in human urine by using liquid chromatography‐tandem mass spectrometry
Authors: Masuda Yuichi , Kanayama Norihiro , Manita Shigeru , Ohmori Satoshi , Ooie Tsuyoshi 
Published: May 2007

AbstractNew bioanalytical methods have been developed for the determination of imidafenacin (KRP‐197/ONO‐8025, IM), a novel antimuscarinic drug developed for the treatment of overactive bladder, and its metabolites, M‐2, M‐3, M‐4, M‐6 and M‐8 (method 1), M‐5 and M‐9 (method 2) in human urine by using liquid chromatography–tandem mass spectrometry. In each method, the urine sample was extracted by solid‐phase extraction, separated on a semi‐micro high‐performance liquid chromatography column using gradient elution and detected by tandem mass spectrometer with an atmospheric pressure chemical ionization or ionspray interface. Extraction recoveries of IM and metabolites were 81.4% or more. Calibration curves had good linearity in the concentration ranges 0.2–50 ng/mL for IM, M‐2, M‐3, M‐4, M‐6 and M‐8 (method 1) and 1–250 ng/mL for M‐5 and M‐9 (method 2), respectively. The accuracy and precision in the intra‐day and inter‐day reproducibility tests were within ±17.0 and 16.1% at the lowest concentrations, and within ±12.8 and 11.1% at higher concentrations, respectively. Using these analytical methods, excretion profiles of IM and its metabolites in human urine were successfully determined after oral administration of IM at the therapeutic dosage of 0.1 mg. Copyright © 2007 John Wiley & Sons, Ltd.
Convenient and rapid determination of cimetidine in human plasma using perchloric acid‐mediated plasma protein precipitation and high‐performance liquid chromatography
Authors: Jantratid Ekarat , Prakongpan Sompol , Foley Joe P. , Dressman Jennifer B. 
Published: May 2007

AbstractThis study demonstrates the analysis of cimetidine in human plasma with HPLC using a simplified sample preparation by protein precipitation with perchloric acid. Plasma cimetidine concentration was determined by plotting peak height ratio of cimetidine to ranitidine (internal standard, IS) against cimetidine concentrations in plasma. The cimetidine and ranitidine peaks were completely separated and no interference from plasma was observed. The lower limit of quantification (LLOQ) of the method was established at 0.1 µg/mL with a precision of 4.3% and a relative error of 1.9%. The average analytical recovery was >90% over the range of cimetidine concentrations (0.1–15.0 µg/mL). The linearity of calibration curve was excellent (r2 > 0.999). The within‐ and between‐day precision and accuracy, expressed as the coefficients of variation and relative error, were found to be less than 5%. Compared with previously reported methods, the analytical technique for cimetidine determination in human plasma presented here demonstrates comparable accuracy and precision, an acceptable analysis time, shorter and simpler sample preparation, and a reduced need for complicated equipment. The method presented here is simple and rapid, and the precision and sensitivity are appropriate for the determination of cimetidine in plasma in pharmacokinetic studies. Copyright © 2007 John Wiley & Sons, Ltd.
Sensitive determination of MDMA and its metabolite MDA in rat blood and brain microdialysates by HPLC with fluorescence detection
Authors: Tomita Mamoru , Nakashima Mihoko N. , Wada Mitsuhiro , Nakashima Kenichiro 
Published: May 2007

AbstractSimultaneous determination of 3,4‐methylenedioxymethamphetamine (MDMA) and 3,4‐methylenedioxyamphetamine (MDA) in rat blood and brain microdialysates by high‐performance liquid chromatography with fluorescence detection (HPLC‐FL) was developed. Microdialysates were directly subjected to derivatization with 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)benzoyl chloride (DIB‐Cl). The DIB‐derivatives of MDMA, MDA and the internal standard, 1‐methyl‐3‐phenylpropylamine (MPPA), were isocratically separated on an ODS column using a mixture of 50 mm phosphate buffer (pH 7.0)–acetonitrile–methanol–2‐propanol (50:45:5:2, v/v/v/v %) as an eluent at a flow rate of 1.5 mL/min. The calibration curves of MDA and MDMA spiked to blood and brain microdialysates were linear over the ranges 2.5–500 and 5.0–1000 ng/mL, respectively. The detection limits of MDA and MDMA were 1.2 and 4.2 for blood and 1.3 and 4.8 ng/mL for brain, respectively. Additionally, the intra‐ and the inter‐assay precisions were lower than 5.6% for the blood and brain microdialysates (n = 4). The proposed method was successfully applied for the monitoring of MDMA and its metabolite MDA in rat blood and brain microdialysates, and the pharmacokinetic parameters of MDMA and MDA in the microdialysates after administration of MDMA (5 mg/kg, i.p.) with or without caffeine (20 mg/kg, i.p.) were evaluated. Copyright © 2007 John Wiley & Sons, Ltd.
Molecularly imprinted solid‐phase extraction combined with molecularly imprinted polymer‐sensor: a diagnostic tool applicable to creatine deficiency syndrome
Authors: Sharma Piyush Sindhu , Lakshmi Dhana , Prasad Bhim Bali 
Published: May 2007

AbstractPrimary creatine deficiency syndromes (CDS) are a new group of disorders caused by guanidinoacetate methyltransferase (GAMT) deficiency, which affects endogenous creatine biosynthesis with depletion of body creatine. A deficiency in creatine can be corrected by treatment with oral creatine supplementation and this necessitates a simple and sensitive screening method for early detection of creatine in dilute physiologic fluids. In this work an artificial receptor, molecularly imprinted polymer (MIP), for creatine was used both as a material for solid‐phase extraction (SPE) and as a sensing element in a voltammetric sensor. Using the combination of molecularly imprinted solid‐phase extraction (MISPE) with a complementary MIP sensor, the minimum detectable amount was found to be 0.0015 ng mL−1 (RSD = 1.3%, S/N = 3). The MISPE‐MIP sensor combination provided up to 60‐fold preconcentration, which was more than sufficient for achieving the required quantification limit 50 ng mL−1 (or 0.0025 ng mL−1 after 2 × 104‐fold dilution) for creatine in human blood serum. Copyright © 2007 John Wiley & Sons, Ltd.
Dynamic binding capacity of plasmid DNA in histidine–agarose chromatography
Authors: Sousa F. , Prazeres D. M. F. , Queiroz J. A. 
Published: May 2007

AbstractThe use of histidine–agarose chromatography in the purification of supercoiled (sc) plasmid DNA (pDNA) from Escherichia coli lysates has been reported recently. In the current work we describe a set of breakthrough experiments which were designed to study the effect of parameters such as flow‐rate, temperature, concentration and conformation on the dynamic binding capacity of pDNA to the histidine support. One of the most striking results shows that the dynamic binding capacity for sc pDNA decreases linearly from 250.8 to 192.0 µg sc pDNA/mL when the temperature is varied from 5 to 24°C. This behaviour was attributed to temperature‐induced, pre‐denaturation conformational changes which promote the removal of negative superhelical turns in sc pDNA molecules and decrease the interaction of DNA bases with the histidine ligands. The capacity for sc pDNA was highly improved when using feeds with higher pDNA concentrations, a phenomenon which was attributed to the fact that pDNA molecules in more concentrated solutions are significantly compressed. A maximum capacity of 530.0 µg pDNA/mL gel was obtained when using a 125 µg/mL pDNA feed at 1 mL/min and 5°C, a figure which is comparable to the plasmid capacity values published for other chromatographic supports. Finally, a more than 2‐fold increase in capacity was obtained when changing from open circular to sc pDNA solutions. Overall, the results obtained provide valuable information for the future development and implementation of histidine chromatography in the process scale purification of pDNA. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitative gas chromatography/time‐of‐flight mass spectrometry: a review
Authors: Williamson Leah N. , Bartlett Michael G. 
Published: May 2007

AbstractTime‐of‐flight (TOF) instruments have recently gained popularity in quantitative analyses. Normally, TOF mass spectrometers are used for accurate mass measurements for empirical formula verification. However, over the past decade, they have been used quantitatively as well. Because of the fast separations and narrow peaks that result from gas chromatography separations, scanning mass spectrometers are not ideal detectors. TOF mass spectrometers, however, have the ability to collect spectra at a faster rate. Two‐dimensional gas chromatography has also been introduced to further resolve peaks from complex matrices. Two‐dimensional gas chromatography results in a faster separation as well as narrower peaks. This paper reviews the methods currently in the literature for the quantitation of compounds using one‐ and two‐dimensional gas chromatography and TOF mass spectrometry detection. Copyright © 2007 John Wiley & Sons, Ltd.
Searching for Stable, Five‐Coordinate Aquated Al(III) Species. Water Exchange Mechanism and Effect of pH.
Authors: Hanauer Hans , Puchta Ralph , Clark Timothy , van Eldik Rudi 
Published: May 2007

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.