bluuebunny/crossref_metadata_2025 huggingface dataset:
The Application of Linear Piecewise Regression to Basal Body Temperature Data
Authors: Teeter Rebecca A.
Published: May 2007

In many situations one wishes to fit a piecewige regression which enables one to obtain estimates of the join points as well as the slopes and intercepts of the fitted submodels. This study developes a technique for fitting piecewise models to data which contain measurement error in an independent variable. The technique developed here combines the HUDSON (1966) procedure for estimating parameters in piecewise regression and the WALD (1940) Grouping Technique which obviates the problem of measurement error.

If one assumes some knowledge of the position of the join point in relation to the data, methodology has been developed to estimate the parameters and study the asymptotic properties of the means and variances of the parameter estimates. However, in the more realistic case, when additional knowledge is limited, it is only possible to obtain the parameter estimates using an iterative technique (TEETER, 1982).

The general technique for obtaining the join point estimate in the presence of measurement error is presented here and an example is given using data on women's basal body temperature during menstrual cycles.
Evaluation of the Subsample from the Non‐respondents by a Random Response Design
Authors: Bouza C. N.
Published: May 2007

The Random Response Design is used for obtaining information from the non respondents. The existence of a refusal to respond may be the cause of non responses. The model obtained seems to be a good alternative for reducing non sampling errors due to dishonest answers.
Reasoning by Analogy from ANOVA to CATANOVA
Authors: Onukogu Ike B.
Published: May 2007

This paper shows that categorical data can be analysed by analysis of variance methods; applying least squares, linear additive models, F‐teste for significance and so forth. It enriches an alternative analysis which leads to chi‐square tests, c.f. author (1982), LIGHT and MARGOLIN (1971).
A Comparison Between Recurrence Risks and Conditional Recurrence Risks Based on the Semi‐Symmetric Intraclass Contingency Table
Authors: Khamis H. J.
Published: May 2007

Recurrence risks are compared to conditional recurrence risks under certain association models corresponding to the underlying semi‐symmetric intraclass contingency table. Ratios of mean squared errors are used to make the comparisons. A study of the comparisons corroborates the theory of KHAMIS and HINKELMANN (1984), and gives new insight into the disease‐genotype association problem.
On the Stereological Estimation of Numerical Density of Particle Systems by an Object Counting Method
Authors: Voss K. , Stoyan D.
Published: May 2007

The determination of numerical density Nv of particles is one of the most complex problems in stereology. This paper presents a method for solving it, consisting only of counting of intersections between particles and thick slices of some different thicknesses. The essential stereological parameters Nv and mean caliper diameter D of the particles are determined by means of a regression line. The basic formula is a simple consequence of general principles for deriving stereological formulae which is described in this paper. The object counting method is applicable if the particles are convex and if the whole particle system can be described by a stationary isotropic ergodic marked point process. A practical example (liver cell nuclei of rats) demonstrates the application of the method.
Hunter Movement and its Role in National Game Bird Surveys
Authors: Sen A. R. , Collins B. T.
Published: May 2007

Analysis of sample survey data on the species composition of waterfowl kill for resident and nonresident hunters for provinces of Canada during 1974 and 1975 showed that a successful game bird hunter who hunted in more than one area (degree block) had both a higher average season kill and more successful days of hunting in which one or more birds were bagged, than one who hunted in the same area during the season. Adjustment for days hunted resulted in a higher daily hunting for those who hunted in more than one degree block. However, the higher kill of the successful hunter is attributable more to a larger number of days hunted than to a larger kill per successful day. Also, hunters hunting in more than one degree block had their successful hunting days more evenly spread across the season.

The estimates of kill per successful hunter and days hunted for stratified sampling by areas of hunting were considerably more efficient than simple random sampling.
Comparison of SANOVA Procedure of Simultaneous Testing Hypotheses to Others
Authors: Graboś Z. , Drwièa T.
Published: May 2007

In this paper a procedure SANOVA of simultaneous testing hypotheses is compared with others used in analysis of variance in a fixed linear model. The geometrical relation between SANOVA and Scheffé's confidence regions is discussed. It is shown that individual confidence intervals from SANOVA procedure are not longer than Scheffe's, Dunnett's and Tukey's ones. The cases, when they are the same are indicated. Theoretical considerations are illustrated by a practical example.
Log‐Linear Model Analysis of the Disease‐Genotype Association Problem: Two‐Loci Case
Authors: Khamis H. J.
Published: May 2007

The log‐linear model is modified in order to adapt it to the disease‐genotype association problem, where two loci are involved. By so doing, the structure of associations among the genetic variables can be determined, and sources of distortion can be identified in certain test statistics and coefficients of association.
Univariate Dose‐Response Models in Case‐Control Studies
Authors: Schmitz P. I. M.
Published: May 2007

For modelling dose‐response relationships in case‐control studies the multiplicative logistic regression model, assuming the relative risk to be an exponential function of the dose, is widely known. If the relative risk is assumed to be a linear function of the dose, several authors (see e.g. BERRY (1980)) have proposed an additive (linear) model. This model has a better fit with the data if such a linear relation holds. Confidence limits for the relative risk derived from the information matrix, however, appear to be rather inaccurate. Therefore, use of the ‘standard’ logistic model in two different ways was studied: extension with a quadratic term or a logarithmic transformation of the dose. By applying the methods both to an empirical data set and in a simulation experiment, it is shown that appropriate transformation (often logarithmic) of the dosage and then applying the ‘standard’ logistic model is an useful approach if a linear dose‐response relationship holds.
Tolerance Limits which Control Percentages in Both Tails: Sampling from Mixtures of Normal Distributions
Authors: Kocherlakota Subrahmaniam , Balakrishnan N.
Published: May 2007

A study is made of the effects of nonnormality on the tolerance limits which control percentages in both tails. The type of nonnormality considered here is the mixtures of normal populations. The conclusions we have arrived at are that the effect of sampling from such a population is essentially to raise the value of γ. For the prescribed level of γ to be achieved, in the equal percentage case, the value of k is smaller than that of the normal case. However, the loss incurred as a result of using Owen's normal values of k is more than offset by the cost of determining k appropriate to this situation. Also, the deviation in the values of γ from the prescribed levels is extremely small.
An Application of Covariance Technique in Diallel Crosses for Griffing Method I & III
Authors: Kaushik L. S. , Hasija R. C.
Published: May 2007

In the present investigation, the analysis of Covariance technique has been applied to method I & III of GRIFFING (1956) of diallel crosses for obtaining the precised estimates of general combining ability (g.c.a), specific combining ability (s.c.a) and reciprocal differences. The adjusted estimates of g.c.a, s.c.a and reciprocal differences and sum of squares due to these parameters and variances due to the estimates of parameters and their comparisons are also derived. The gain in precision in estimating the parameters due to the use of covariance technique has been illustrated with the help of an example.
Determination of the Covariance of Random Sets from Thin Sections
Authors: Gerlach W. , Stoyan D.
Published: May 2007

The problem of stereological determination of the covariance of a random set from thin sections is considered. Using results of numerical experiments for two examples, a simple approximation formula is suggested.
Analysis of Diallel Table for Experiments in Block Designs
Authors: Ceranka B. , Kielczewska H.
Published: May 2007

In this paper the analysis of genotypes obtained in diallel crossing system, including parents, one set of F1s and reciprocal F1's, is given. This analysis is presented for data obtained from the experiments laid out in block designs. The analysis of variance, estimator of reciprocal effects, estimators of general and specific combining abilities as well as statistics for testing of hypotheses concerning those parameters are given.
The Almost‐one Parameter Hypothesis Applied to Pharmacokinetics of Ethanol Infusion
Authors: Masuyama M.
Published: May 2007

They say that the pharmacokinetics of constant‐rate intravenous infusion of ethanol obeys the Henri‐Michaelis‐Menten (H‐M‐M) model. In analysing the original data from the viewpoint of the almost‐one parameter hypothesis (see box 1), we found that the whole process should be divided into four phases and the H‐M‐M model was valid only in the last phase.
Optimization of Taxonomic Keys by Means of Probabilistic Modelling
Authors: Sviridov A. V. , Leuschner D.
Published: May 2007

At present biological systematics, i. e. classification and identification of organisms, is also a subject of the employment of mathematical methods. The topic of this paper is identification. One of the most important methods of identification is that by means of keys. Therefore a short review on the types of keys and their valuation is represented. Moreover there are discussed the essential properties of keys: reliability and velocity of identification. Further in connection with these two quantities probabilistic models are treated. The last part of the article deals with the optimization of keys concerning theory and practice of the problem.
A Multivariate Analysis of Variance of Categorical Data
Authors: Onukogu Ike B.
Published: May 2007

Two methods of testing multivariate hypotheses in an IXJXK contingency table are presented. In one case, use is made of the trace of the matrix of sum of squares and sum of products while in the other, determinants of the matrices are used to construct test statistics. Asymptotic equivalence of the methods is shown.
The Two Period Binary Response Cross‐Over Trial
Authors: Nagelkerke N. J. D. , Hart A. A. M. , Oosting J.
Published: May 2007

The cross‐over design for clinical trials when responses are binary is discussed. Three tests which have been proposed for the analysis of this problem are compared by an assessment of their assumptions. A simple test to establish whether it is appropriate to include observations from the second period is presented.
Two Stage Sampling for Simultaneously Testing Main and Side Effects in Clinical Trials
Authors: Bauer P.
Published: May 2007

In clinical trials for the comparison of two treatments it seems reasonable to stop the study if either one treatment has worked out to be markedly superior in the main effect, or one to be severely inferior with respect to an adverse side effect. Two stage sampling plans are considered for simultaneously testing a main and side effect, assumed to follow a bivariate normal distribution with known variances, but unknown correlation. The test procedure keeps the global significance level under the null hypothesis of no differences in main and side effects. The critical values are chosen under the side condition, that the probability for ending at the first or second stage with a rejection of the elementary null hypothesis for the main effect is controlled, when a particular constellation of differences in mean holds; analogously the probability of ending with a rejection of the null hypotheses for the side effect, given certain treatment differences, is controlled too. Plans “optimal” with respect to sample size are given.
On the Accuracy of Numerical Solutions for Some Stereological Problems such as the Wicksell Corpuscle Problem
Authors: Gerlach W. , Ohser J.
Published: May 2007

Two stereological problems—the estimation of sphere diameter distributions and the estimation of sheet thickness distributions from linear or plane sections—are considered. Their numerical solution consists in the solution of linear equation systems. To compare the quality of various methods theoretically, not only by experiments, the condition numbers of the matrices of the corresponding equation systems are determined.
Analysis of Trends in Proportions with an Ordinally Scaled Determinant
Authors: Nurminen M.
Published: May 2007

In this paper the analysis of several proportions in a comparative study setting is discussed. The case of ordinal grouping variates is considered. F statistics are formulated to test for trend in the proportions over the scored values of the determinant variate. The null chi‐square or F (t square) functions are presented separately for the unstratified and stratified analysis, and in either situation the corresponding functions with angular transformed proportions are also expressed. Generalizations to deal with the parameters in the nonnull range are outlined. Throughout, the intimate relation between the presented statistics and standard methods is pointed out.
Interaction Pair‐potentials for a System of Ant's Nests
Authors: Takacs R. , Fiksel Th.
Published: May 2007

In this paper two methods for the estimation of pair‐potentials of Gibbsian point processes are described. These are applied to a point pattern of ant's nests to obtain information on the degree of interaction of two different species. Furthermore an estimation method of mark‐point potentials is demonstrated and applied to the same example.
A Multistate Markov Chain Model for Evaluating a Sterilization Policy
Authors: Biswas S. , Pachal T. K.
Published: May 2007

A multistate Markov chain model corresponding to varying fertility and mortality rates at different levels of surviving children of a couple was developed. Asymptotic probabilities of having a fixed number of children have been worked out.
Some Extensions of Buser and Baroni‐Urbani's Clustering Method
Authors: Dragomirescu L.
Published: May 2007

We consider that the algorithm of numerical taxonomy focused upon the concept of “homogeneity”, proposed by Buser and Baroni‐Urbani (1982) for binary data, satisfies best from all the other algorithms known by us, the conditions of classification in biology formulated by Beckner in 1959. Therefore the paper proposes and studies homogeneities for binary and for ordered multi‐states data, which model explicitly Beckner's conditions. From all these, the homogeneity denoted by h* has the remarkable quality of generalizing the famous Jaccard's similarity coefficient. Moreover, using h* in this algorithm “naturally” improved by us, we can achieve the performance of a correct classification of the remarkable example proposed by Watanabe (1969).
Robustness of Selection Procedures
Authors: Domröse H. , Rasch D.
Published: May 2007

In the article Bechhofers Indifference‐zone formulation for selecting the t populations with the t highest means is considered in a set of non‐normal distributions.

Selection rules based on the sample mean, the 10% and the 20% trimmed means, two estimators proposed by Tiku (1981) for valuating the smallest and highest accepted sample values higher, the sample median and a linear combination of quantile estimators, two adaptive procedures and a ranksum procedure are investigated in a large scale simulation experiment in respect of their robustness against deviations from an assumed distribution. Robustness is understood as a small percentage of the difference βA‐β between the actual probability of incorrect selection βA and the nominal β‐value. We obtained a relatively good robustness for the classical sample mean selection rule and useful derivations for the employment of other selection rules in an area of practical importance.
Phenotypic Stability of Mixtures – Relations Between the Stability Parameters of a Mixture and Its Components
Authors: Hühn M.
Published: May 2007

For each of the two stability parameters (‘regression coefficient’ and ‘sum of squared deviations from the regression’) of the common regression approach (= regression of the yield of population i in environment j on the environmental index of this evironment j which often has been estimated by the mean of all tested populations in this environment j) the phenotypic stability of a mixture and it's components have been analysed theoretically. It can be shown that in practical applications (for example: variety testing) the regression coefficient of a mixture often can be sufficiently approximated by the arithmetic mean of the regression coefficients of the components grown singly. This simple relation between a mixture and it's components don't hold for the second stability parameter ‘sum of squared deviations from the regression’. The exact relation has been deduced and useful and clear approximations are discussed. All the theoretical results are demonstrated and applied using the well‐known experimental barley data of Sandfaer (1970).
A Note on the Analysis of the Two‐Period Crossover Design When the Period‐Treatment Interaction is Significant
Authors: Grieve A. P.
Published: May 2007

In the analysis of a two‐period crossover study Grizzle (1965) suggests that, if a preliminary test for a period by treatment interaction (residual effect, carryover effect) is significant at the 10 % level, the direct effects of the treatments should be compared by performing a t‐test on the data from the first period only. In this note it is shown that under Grizzle's model the comparison of the direct treatment effects is equivalent to a Behrens‐Fisher problem. Depending on one's viewpoint–Bayesian, fiducial, or sampling theory–different solutions are possible. The solutions are illustrated using three well‐known data sets.
Discretizing a Normal Prior for Change Point Estimation in Switching Regressions
Authors: Piegorsch Walter W.
Published: May 2007

Bayes decision procedures are considered for change point estimation in the simple bilinear segmented model. A discretized normal prior density is employed as the prior distribution for the change point index. Posterior probability functions are developed for this index under a vague prior formulation on the regression parameters. The procedure is applied to an example involving mercury toxicity data.
One‐ and Two‐Sample Tests of Kendall's τ
Authors: Schemper M.
Published: May 2007

Several methods of testing general one‐sample and two‐sample hypotheses of Kendall's τ are discussed. The performance of these procedures in typical situations likely to occur in practice was investigated by numerous Monte Carlo experiments. The common one‐sample test (H0: τ = 0) based on the permutational variance performs very similar to bootstrap or jackknife testing for true τ near zero. For true |τ| perhaps greater than 0.4 and moderate sample sizes bootstrap techniques are the methods of choice.
Analysis of Diallel Table for Experiments Carried Out in BIB Designs‐Mixed Model
Authors: Ceranka B. , Mejza S.
Published: May 2007

In this paper the analysis of genotypes obtained in a diallel crossing system, including parents, one set of F1′s and reciprocal F1′s, is given. This analysis is presented for data obtained from the experiments carried out in a block design in which block effects are random. The analysis of variance, estimators of reciprocal effects, estimators of general and specific combining abilities are considered. Also statistics for testing hypotheses concerning some genetical parameters are given.
Robustness of Multiple Comparison Procedures: Treatment versus Control
Authors: Rudolph P. E.
Published: May 2007

Computer simulation techniques were used to investigate the Type I and Type II error rates of one parametric (Dunnett) and two nonparametric multiple comparison procedures for comparing treatments with a control under nonnormality and variance homogeneity. It was found that Dunnett's procedure is quite robust with respect to violations of the normality assumption. Power comparisons show that for small sample sizes Dunnett's procedure is superior to the nonparametric procedures also in non‐normal cases, but for larger sample sizes the multiple analogue to Wilcoxon and Kruskal‐Wallis rank statistics are superior to Dunnett's procedure in all considered nonnormal cases. Further investigations under nonnormality and variance heterogeneity show robustness properties with respect to the risks of first kind and power comparisons yield similar results as in the equal variance case.
Spread of Drug Addiction in the Presence of Two Competing Drugs
Authors: Dayananda P. W. A.
Published: May 2007

This paper considers the spread of drug addiction when addiction is by taking one of two competing drugs available. Community is assumed to be closed and each individual is classified as belonging to one of three mutually exclusive groups: susceptibles, addicts and pushers. A deterministic model is presented in general form and, in a special case, the stochastic model is analysed. An illustration is also presented where the parameters take a specific set of numerical values.
Cycloaddition Reactions of 16‐Electron d4 Metallocene Complexes with C60: A Theoretical Study
Authors: Sheu Jeng‐Horng , Su Ming‐Der
Published: May 2007

The potential‐energy surfaces of the cycloaddition reaction Cp2M+C60→Cp2M(C60) (Cp=η5‐C5H5; M=Cr, Mo, and W) were studied at the B3LYP/LANL2DZ level of theory. Two competing reaction pathways were found, which can be classified as [6,5] attack (path A) and [6,6] attack (path B). Given the same reaction conditions, the [6,6]‐attack pathway for cycloaddition to C60 is more favorable than the [6,5]‐attack pathway, both kinetically and thermodynamically. A qualitative model, based on the theory of Pross and Shaik, was used to develop an explanation for the reaction barrier heights. Thus, our theoretical findings suggest that the singlet–triplet splitting ΔEst (=Etriplet−Esinglet) of the 16‐electron d4 Cp2M and C60 species are a guide to predicting their reactivity towards cycloaddition. Our model results demonstrate that the propensity for cycloaddition to C60 increases in the order Cp2Cr<Cp2Mo<Cp2W. We show that both electronic and geometric effects play a decisive role in determining the energy barriers and reaction enthalpies.
Leukemic involvement is a common feature in mantle cell lymphoma
Authors: Ferrer Ana , Salaverria Itziar , Bosch Francesc , Villamor Neus , Rozman María , Beà Silvia , Giné Eva , López‐Guillermo Armando , Campo Elías , Montserrat Emili
Published: May 2007

BACKGROUND.

The reported incidence of peripheral blood involvement in patients with mantle cell lymphoma (MCL) ranges from 13% to 77%. The aim of the study was to analyze the prevalence and the biologic and clinical significance of leukemic involvement in a series of patients with MCL.

METHODS.

Leukemic expression was assessed by conventional morphology and flow cytometry (FC) in 48 patients. In addition, comparative genomic hybridization (CGH) was performed in 27 patients.

RESULTS.

At diagnosis, 44 patients (92%) had evidence of leukemic expression by FC, including 8 patients (17%) without morphologically apparent leukemic involvement. Moreover, a lymphocyte count ≥5 × 109/L was observed in 25 cases (52%). The most frequent imbalances detected by CGH were gains of 3q, 7p, 8q, 9q, 12q, and 13q, and losses of 13q, 1p, 9p, 11q, 10p, 17p, 6q, 8p, and 9q. Using a cutoff of 5 × 109/L lymphocytes, cases with lymphocytosis more frequently presented with gains of 3q (P = .02), losses of 10p (P = .05), a low response rate (P = .04), and a short survival (P = .05).

CONCLUSIONS.

Leukemic expression at diagnosis detected by FC was found to be highly frequent in this series of patients with MCL. Although morphologically apparent leukemic expression was not associated with specific chromosomal alterations detected by CGH, a lymphocyte count ≥5 × 109/L was correlated with particular genetic abnormalities and a poor outcome. Cancer 2007. © 2007 American Cancer Society.
Xeya3 regulates survival and proliferation of neural progenitor cells within the anterior neural plate of Xenopus embryos
Authors: Kriebel Martin , Müller Frank , Hollemann Thomas
Published: May 2007

The transcriptional coactivater and tyrosine phosphatase eyes absent (eya) is vital for eye development in Drosophila. We identified a vertebrate member of the Eya family, Xeya3, which is expressed in the anterior neural plate, including the eye field. Overexpression of wild‐type Xeya3 or of a phosphatase‐negative version of Xeya3 creates massive enlargements of brain and retinal tissues, mainly caused by overproliferation of neural precursor cells. On the other hand, suppression of Xeya3 function induces local apoptosis within the sensorial layer of the anterior neuroectoderm. Thus, Xeya3 is key factor for the formation and size control of brain and eyes in vertebrates. Developmental Dynamics 236:1526–1534, 2007. © 2007 Wiley‐Liss, Inc.
Structure Determination of Photoproducts of Anthracenes with (Arylmethoxymethyl) Sidechains
Authors: Dobis Silvia , Schollmeyer Dieter , Gao Chunmei , Cao Derong , Meier Herbert
Published: May 2007

Irradiation of 9‐(arylmethoxymethyl)anthracenes 3 leads either to a cyclomer and cyclodimer mixture (3a → 4a,5a), to selectively formed dimers (3b → 5b), or a selectively formed cyclomer (3c → 4c). The [4π+4π]cyclodimerization is under the conditions used a regioselective head‐to‐tail process. In the crystals of the dimers 5a,b, the sidechains are attached in an antiperiplanar position related to the CC bonds generated in the dimerization. In solutions, however, the structures consist of three rotamers the equilibration of which was studied by temperature‐dependent NMR spectra. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
MEKC combined with SPE and sample stacking for multiple analysis of pesticides in water samples at the ng/L level
Authors: Ravelo‐Pérez Lidia M. , Hernández‐Borges Javier , Cifuentes Alejandro , Rodríguez‐Delgado Miguel Á.
Published: May 2007

In this work, a new multiresidue analytical method based on MEKC with UV detection combined with SPE as off‐line preconcentration strategy, and reversed‐electrode polarity stacking mode (REPSM) as on‐line stacking procedure, has been developed for the monitoring of 12 pesticides (carbendazim, pirimicarb, metalaxyl, pyrimethanil, procymidone, nuarimol, azoxystrobin, tebufenozide, fenarimol, benalaxyl, penconazole, and tetradifon) that are currently being used in the Canary Islands (Spain). The optimized MEKC buffer, consisting of 100 mM sodium tetraborate and 30 mM SDS at pH 8.5 with 6% v/v 1‐propanol, provided baseline resolution of the 12 pesticides in less than 20 min. The developed method was applied to the analysis of mineral, stagnant, and tap water samples. The proposed SPE‐REPSM‐MEKC‐UV method showed high extraction efficiencies with detection limits (LODs) at the low ng/L level providing LOD values down to 64 ng/L for these real samples.
The Xichong flora of Yunnan, China: diversity in late Mid Devonian plant assemblages
Authors: Yi Wang , Berry C. M. , Shougang Hao , Honghe Xu , Qiang Fu
Published: May 2007

Over the past 10 years, significant progress has been made in our understanding of late Mid Devonian floras of Yunnan Province, China. Based on new collections and a restudy of existing specimens, most of the old taxa have been emended, and some new taxa described. The late Mid Devonian Xichong flora of Yunnan is dominated by lycopsids, including prelycopsids, homosporous and herbaceous protolepidodendrids. The ‘fern’‐like and cladoxylopsid plants are important and are mainly endemic. A few small plants have also been reported. The Xichong flora is divided into two ecological levels: small tree and ground cover levels. The palaeoclimate of late Mid Devonian Yunnan belonged to the tropical zone. There are noticeable differences between the fossil plants of Yunnan and those of the late Mid Devonian in Laurussia and Venezuela. The Xichong flora is a special, endemic flora in a palaeogeographically isolated tropical area, controlled by local palaeoclimate. The sequence of floras developed in pre‐Carboniferous time in South China includes the Posongchong (Pragian), the Xichong (late Givetian) and the Wutung (late Famennian) floras. These floras are treated as pre‐Cathaysian floras. Further work is required to establish how much influence these pre‐Cathaysian floras had in the Carboniferous‐Permian development of the Cathaysian Flora. Copyright © 2007 John Wiley & Sons, Ltd.
Nitroimidazoles, part 4: Synthesis and anti‐HIV activity of new 5‐alkylsulfanyl and 5‐(4′‐arylsulfonyl)piperazinyl‐4‐nitroimidazole derivatives
Authors: Al‐Soud Yaseen A. , Al‐Masoudi Najim A. , De Clercq Erik , Paneccoque Christoph
Published: May 2007

The development of new HIV nonnucleoside reverse transcriptase inhibitors (NNRTIs) offers the possibility of generating structures of increased potency. On this basis, a series of 5‐alkylsulfanyl and 5‐(4′‐arylsulfonyl)piperazine derivatives of 1‐phenyl‐2‐alkyl‐4‐nitroimidazoles 5–21 was synthesized with the aim to develop new NNRTIs. The new synthesized compounds were assayed against HIV‐1 and HIV‐2 in MT‐4 cells. Compounds 9 and 13, with an alkylsulfanyl group at C‐5 of the 4‐nitroimidazole backbone, showed inhibition of HIV‐1 with EC50 4.04 μg/mL and 2.37 μg/mL, and therapeutic indexes (SI) of 17 and 13, respectively. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:333–340, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20301
A simple and convenient procedure for the synthesis of naphthoquinone fused cyclic α‐aminophosphoryl chloride
Authors: Wang Bin , Miao Zhiwei , Chen Ruyu
Published: May 2007

The synthesis of a novel quinone fused phosphorus heterocycle, 2‐chloro‐3,3‐disubstituents‐3,4‐dihydro‐2H‐naphtho[2,3‐e][1,4,2]oxazaphosphinane‐5,10‐dione 2‐oxide (3a–g), was described for the first time. These compounds, which have a readily leaving group Cl, can serve as intermediates of many quinone fused phosphorus heterocycles. The structures of 3a–g were characterized by using common spectroscopic methods. According to the X‐ray structure of 3a, these compounds may be used as DNA‐intercalators. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:359–362, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20306
Reactions with 3,6‐diaminothieno[2,3‐b]‐pyridines: Synthesis and characterization of several new fused pyridine heterocycles
Authors: Gad‐Elkareem Mohamed A. M. , Elneairy Mohamed A. A. , Taha Adel M.
Published: May 2007

6‐Aminopyridine‐2(1H)thiones 1 reacting with α‐halo‐compounds 2a–c afforded the alkylthiopyridine derivatives 3a–c which in turn cyclized to the corresponding thieno[2,3‐b]pyridine derivatives 4a–c. Several thieno[2,3‐b]pyridine derivatives 7, 16, 19, pyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidine derivatives 6a,b, 11a–c, 21 and pyrido[3′,2′:4,5]thieno[3,2‐c]pyridazine derivatives 13, 17 were prepared starting from compounds 4a–c. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:405–413, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20313
Synthesis of 4‐(5‐aryl‐1,3,4‐oxadiazol‐2‐yl)phenyl‐hydrazine derivatives from 3‐(4‐hydrazinocarbonyl‐phenyl)sydnones
Authors: Chang Hung‐Te , Chiang Kuo‐Chen , Wong Fung Fuh , Huang Chun‐Sheng , Liao Yang‐Ming , Kuo Wen‐Fa , Won Shaw‐Bing , Yeh Mou‐Yung
Published: May 2007

The synthesis of potential fluorescent active 4‐(5‐aryl‐1,3,4‐oxadiazol‐2‐yl)phenylhydrazine derivatives was accomplished in three steps. The key step was the dehydration cyclization of 1,2‐diacylhydrazines to form the 1,3,4‐oxadiazole ring by use of acetic anhydride/perchloric acid mixture as the dehydrating agent. The sydnone moiety served as the masked hydrazines, which could be demasked by HCl for further application. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:438–442, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20318
Inhibiting triglyceride synthesis improves hepatic steatosis but exacerbates liver damage and fibrosis in obese mice with nonalcoholic steatohepatitis
Authors: Yamaguchi Kanji , Yang Liu , McCall Shannon , Huang Jiawen , Yu Xing Xian , Pandey Sanjay K. , Bhanot Sanjay , Monia Brett P. , Li Yin-Xiong , Diehl Anna Mae
Published: May 2007

In the early stages of nonalcoholic fatty liver disease (NAFLD), triglycerides accumulate in hepatocytes. Diacylglycerol acyltransferase 2 (DGAT2) catalyzes the final step in hepatocyte triglyceride biosynthesis. DGAT2 antisense oligonucleotide (ASO) treatment improved hepatic steatosis dramatically in a previous study of obese mice. According to the 2-hit hypothesis for progression of NAFLD, hepatic steatosis is a risk factor for nonalcoholic steatohepatitis (NASH) and fibrosis. To evaluate this hypothesis, we inhibited DGAT2 in a mouse model of NASH induced by a diet deficient in methionine and choline (MCD). Six-week-old genetically obese and diabetic male db/db mice were fed either the control or the MCD diet for 4 or 8 weeks. The MCD diet group was treated with either 25 mg/kg DGAT2 ASO or saline intraperitoneally twice weekly. Hepatic steatosis, injury, fibrosis, markers of lipid peroxidation/oxidant stress, and systemic insulin sensitivity were evaluated. Hepatic steatosis, necroinflammation, and fibrosis were increased in saline-treated MCD diet–fed mice compared to controls. Treating MCD diet–fed mice with DGAT2 ASO for 4 and 8 weeks decreased hepatic steatosis, but increased hepatic free fatty acids, cytochrome P4502E1, markers of lipid peroxidation/oxidant stress, lobular necroinflammation, and fibrosis. Progression of liver damage occurred despite reduced hepatic expression of tumor necrosis factor alpha, increased serum adiponectin, and striking improvement in systemic insulin sensitivity.

Conclusion:

Results from this mouse model would suggest accumulation of triglycerides may be a protective mechanism to prevent progressive liver damage in NAFLD. (Hepatology 2007.)
Domain‐specific impairment of source memory following a right posterior medial temporal lobe lesion
Authors: Peters Jan , Koch Benno , Schwarz Michael , Daum Irene
Published: May 2007

This single case analysis of memory performance in a patient with an ischemic lesion affecting posterior but not anterior right medial temporal lobe (MTL) indicates that source memory can be disrupted in a domain‐specific manner. The patient showed normal recognition memory for gray‐scale photos of objects (visual condition) and spoken words (auditory condition). While memory for visual source (texture/color of the background against which pictures appeared) was within the normal range, auditory source memory (male/female speaker voice) was at chance level, a performance pattern significantly different from the control group. This dissociation is consistent with recent fMRI evidence of anterior/posterior MTL dissociations depending upon the nature of source information (visual texture/color vs. auditory speaker voice). The findings are in good agreement with the view of dissociable memory processing by the perirhinal cortex (anterior MTL) and parahippocampal cortex (posterior MTL), depending upon the neocortical input that these regions receive. © 2007 Wiley‐Liss, Inc.
L‐type voltage‐operated Ca+2 channels modulate transient Ca+2 influx triggered by activation of Sertoli cell surface L‐selectin
Authors: Kao Tzu‐Jen , Millette Clarke F.
Published: May 2007

Near the base of mammalian seminiferous epithelium, Sertoli cells are joined by tight junctions, which constitute the blood–testis barrier. Differentiating germ cells are completely enveloped by Sertoli cells and must traverse the tight junctions during spermatogenic cycle. Following the specific ligand activation of L‐selectin, the up‐regulated Rho family small G‐proteins have been implicated as important modulators of tight junctional dynamics. Although the activation of L‐selectin transmits subsequent intracellular signals in a Ca+2‐dependent fashion in various cell types, little is understood regarding the signaling pathways utilized by L‐selectin in Sertoli cells. Therefore, we have examined the possible resultant calcium influx triggered by specific ligand‐activation of cell surface L‐selectin receptors or by cross‐linking of L‐selectin with anti‐L‐selectin. Spectrofluorimetric studies demonstrate increase of intracellular Ca+2 levels immediately after the treatment of the L‐selectin ligands, fucoidan and sialyl Lewis‐a, or after treatment with anti‐L‐selectin antibody. We then determined the mechanism of Ca+2 influx by investigating L‐ and T‐type voltage‐operated Ca+2 channels, which have been suggested to present in the membranes of Sertoli cells. Data demonstrate that Sertoli cells treated with L‐type voltage‐operated Ca+2 channel antagonists, nifedipine, diltiazem, or verapamil, lead to dose‐dependent blockage of L‐selectin‐induced Ca+2 influx. Cells treated with mibedradil, a T‐type voltage‐operated Ca+2 channel antagonist, results in little or no blocking effect. Therefore, we conclude that activation of Sertoli cell L‐selectin induces Ca+2 influx, which is at least partially regulated by L‐type voltage‐operated Ca+2 channels. J. Cell. Biochem. 101: 1023–1037, 2007. © 2007 Wiley‐Liss, Inc.
Nuclear microenvironment in cancer diagnosis and treatment
Authors: Pezo Rossanna C. , Singer Robert H.
Published: May 2007

The nuclear architecture plays an important role in the temporal and spatial control of complex functional processes within the nucleus. Alterations in nuclear structures are characteristic of cancer cells and the mechanisms underlying these perturbations may directly contribute to tumor development and progression. In this review, we will highlight aspects of the nuclear microenvironment that are perturbed during tumorigenesis and discuss how a greater understanding of the role of nuclear structure in the control of gene expression can provide new options for cancer diagnosis and treatment. J. Cell. Biochem. 104: 1953–1963, 2008. © 2007 Wiley‐Liss, Inc.
Structural, electronic, and optical properties of phosphole‐containing π‐conjugated oligomers for light‐emitting diodes
Authors: Liu Yan‐Ling , Feng Ji‐Kang , Ren Ai‐Min
Published: May 2007

The purpose of this work is to provide an in‐depth interpretation of the optical and electronic properties of a series of phosphole derivatives, including 2,5‐diphenylthiooxophosphole (2a), 2‐phenyl‐5‐biphenylthiooxophosphole (3a), 2‐phenyl‐5‐stilbenylthiooxophosphole (4a), 2,5‐dithienylthiooxophosphole (2b), 2‐thienyl‐5‐biphenylthiooxophosphole (3b), 2‐thienyl‐5‐stilbenylthiooxophosphole (4b), and dibenzophosphole 1. These thiooxophospholes show great potential for application in OLEDs as efficient red emitters due to the tuning of the optical and electronic properties by the use of various substituents at the 2,5‐positions of the phosphole ring. The geometric and electronic structures of the oligomers in the ground state were investigated using density functional theory (DFT) and the ab initio HF, whereas the lowest singlet excited states were optimized with ab initio CIS. To assign the absorption and emission peaks observed in the experiment, we computed the energies of the lowest singlet excited states with time‐dependent DFT (TD‐DFT). All DFT calculations were performed using the B3LYP functional and the 6‐31G (d) basis set. The results show that the HOMOs, LUMOs, energy gaps, ionization potentials, and electron affinities for the phosphole derivatives are significantly affected by varying the phosphole ring substituents at the 2,5‐positions, which favor the hole and electron injection into OLEDs. The absorption and emission spectra exhibit red shifts to some extent [the absorption spectra: 339.63 (1) < 358.65 (2a) < 373.77 (3a) < 443.89 nm (4a) and 403.03 (3b) < 449.11 (2b) < 460.19 nm (4b); the emission spectra: 418.42 (1) < 513.62 (2a) < 556.51 (3a) < 642.59 nm (4a) and 568.31 (2b) < 631.11 (3b) < 647.35 nm (4b)] and the Stokes shifts are unexpectedly large ranging from 78 to 228 nm resulting from a more planar conformation of the excited state for the phosphole derivatives. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
O2/3 exposure inhibits cell progression affecting cyclin B1/cdk1 activity in SK‐N‐SH while induces apoptosis in SK‐N‐DZ neuroblastoma cells
Authors: Cannizzaro A. , Falzacappa C. Verga , Martinelli M. , Misiti S. , Brunetti E. , Bucci B.
Published: May 2007

In search for innovative therapeutic agents for children neuroblastoma, the oxygen therapy could be considered an alternative anti‐tumoral treatment. Given the physiochemical properties of O2/3 gas mixture including fairly low aqueous solubility and spreading, and the interesting perspective of hyperoxia, we analyzed the inhibitory effect of O2/3 treatment on two human neuroblastoma cell lines (SK‐N‐SH and SK‐N‐DZ). In this study, we demonstrated that O2/3 treatment was able to induce cell growth inhibition and cell cycle perturbation in both cell lines. We observed an arrest at G2 phase, accompanied by an alteration in the expression and localization of cyclin B1/cdk1 complex and a reduction in its activity in SK‐N‐SH cells. This reduction was consistent with the increase in both Wee1 and chk1 protein levels. On the contrary, O2/3 induced apoptosis in SK‐N‐DZ cells via caspase 3 activation and Poly ADP‐ribose polymerase‐1 (PARP) cleavage, associated with an increase in the pro‐apoptotic Bax protein. Consequently, we considered the possibility of improving the responsiveness to chemotherapeutic agents such as Cisplatin, Etoposide, and Gemcitabine in combination with O2/3 treatment. The combined treatments produced a stronger cell inhibitory effect than Cisplatin and Etoposide used alone in SK‐N‐SH cells. On the contrary, the combination data were not significantly different from O2/3 treatment alone in SK‐N‐DZ cells, thus suggesting that the obtained changes in cell growth inhibition were due to the effect of O2/3 alone. J. Cell. Physiol. 213: 115–125, 2007. © 2007 Wiley‐Liss, Inc.
The tissue banking in cancer and stem cell research
Authors: Graziano Antonio , Biunno Ida , De Blasio Pasquale , Giordano Antonio
Published: May 2007

The Sapio Award was established in 1999 by the Sapio Group along with several Italian universities and research centers to recognize Italian scientists who have made a major contribution to the discovery or development of novel technologies in the fields of biotechnology, social and health services, nonotechnology and biosecurity in agricultural production and scientific distribution. The 2006 edition of the award meeting centered around the issues of tissue banks and biorepositories and translational medicine. The organizing committee divided this edition into a pre‐meeting held in Milan on October 18, 2006 and a master meeting on October 19, 2006, held at the ISS in Rome. A summary of these meetings is given. J. Cell. Physiol. 212: 345–347, 2007. © 2007 Wiley‐Liss, Inc.
On a Number‐Theoretic Result of Sylvester‐Kronecker‐Zsigmondy
Authors: Steidl G. , Tasche M.
Published: May 2007

Let K be an algebraic extension field of Q. Further, let 𝔒K be the domain of algebraic integers of K, and let Σn(x) be the n‐th cyclotomic polynomial. This paper is devoted to the factorization of the principal ideal Σn(e) 𝔒K(e𝔒K) into prime ideals of 𝔒K. The main result (Theorem 3.4) can be considered as a generalization of a known result of Sylvester, Kronecker and Zsigmondy on the prime factorization of Σn(e) (eϵZ). With Theorem 3.4., we improve corresponding results of Redei [11] and Sachs [14]. We generalize a technique developed in [8] and [3] and we study also the cases that K is a quadratic field and a cyclotomic field, respectively. Finally, we apply the results to the parameter determination of Fourier‐like number‐theoretic transforms in 𝔒K.
Płonka‐Type Sums Over Free Products
Authors: Gardner B. J.
Published: May 2007

A generalization of PŁONKA sums is introduced wherein instead of the disjoint union of underlying sets of algebras, the free product of the reducts (of some type) of the algebras is used as underlying set for the new algebra. Preservation of identities is discussed and a number of examples are presented.
A Priori Estimate for the Discontinuous Oblique Derivative Problem for Elliptic Systems
Authors: Begehr Heinrich , Wen Guo‐Chun
Published: May 2007

Recently [6] an existence as well as a uniqueness theorem for the discontinuous oblique derivative problem for nonlinear elliptic system of first order in the plane, see [12, 19, 23] was proved, based on some a priori estimate from [20]. This estimate, however, is deduced by reductio ad absurdum. Therefore the constants in this estimate are unknown so that the estimate cannot be used for numerical procedures, e.g. for approximating the solution of a nonlinear problem by solutions of related linear problems, see [24, 3, 4]. In this paper a direct proof of an a priori estimate is given using some variations of results from [14], see also [11], where the constants can explicitely be estimated. For related a priori estimates see [1 – 5, 8, 16, 17, 20, 21, 24 – 26]. A basic reference for the oblique derivative problem is [9].
On Parabolic Trigonometry in a Degenerate Minkowski Plane
Authors: Ingarden R. S. , Tamássy L.
Published: May 2007

A Minkowski plane is considered having a parabola as indicatrix curve and taking for its center the vertex of the parabola causing by this a degeneration of the Minkowski geometry. After a short discussion of the concept of the length and angle, the trigonometrical functions of this geometry has been calculated and their basic properties explained. A two‐parameter pseudogroup of generalized rotations has been found as an analogon of the Lorentz transformation group in special relativity. The theory has applications to thermodynamics.
ϵ‐Optimal and Optimal Controls for the Stochastic Linear‐Quadratic Problem
Authors: Tudor C.
Published: May 2007

We study the stochastic regulator problem in Hilbert spaces for systems governed by linear stochastic differential equations with retarded controls and with state and control dependent noise. We use integral Riccati equations and no reference to a Riccati differential equation or to the Ito formula is made.
Von Neumann Representations on Self‐Dual Hilbert W*‐Moduli
Authors: Frank Michael
Published: May 2007

This paper continues the investigations of [4]. Von Neumann algebras M of bounded operators on self‐dual Hilbert W*‐moduli ℋ possessing a cyclic‐separating element x in ℋ are considered. The close relation of them to such special real subspaces K of ℋ as treated in [4] is shown. Under the supposition that the underlying W*‐algebra is commutative, a Tomita‐Takesaki type theorem is stated for von Neumann algebras on self‐dual Hilbert W*‐moduli. The natural cone in ℋ arising from the pair (M, x) is investigated and its properties are obtained.
Strictly Convex Linear 2‐Normed Spaces
Authors: Ha Ki Sik , Cho Yeol Je , Kim Seong Sik , Khan M. S.
Published: May 2007

In this paper, we give several new characterizations of 2‐inner product spaces and strict convexity for linear 2‐normed spaces in terms of orthogonalites and 2‐semi‐inner product spaces.
The Packing Theorem and Packing Measure
Authors: Haase Hermann
Published: May 2007

For a VITALI class of a metric space (X, d) a packing measure is introduced following the ideas of [7]. The Packing Theorem of VITALI is a powerful mean to derive density results for measures [1, 2, 3]. Conversely, the notion of packing measure allows us to give sufficient conditions for a measure that the packing theorem of VITALI hods.