bluuebunny/crossref_metadata_2025 huggingface dataset:
Two criteria for the comparison of multiple arrangements of experiments and their use to answer the question: Is it better to compare p treatment groups with p controls or with a single control
Authors: Horn M.
Published: April 2007

In experimental situations examining the effectiveness of p(p>1) treatments by comparing treated groups and untreated controls the following question arose: Which experimental arrangement is more appropriate, an arrangement A1 using for the p comparisons only one single control, or an arrangement A2 using for every comparison another control. To answer this question two criteria are formulated. The first criterion takes into consideration the expected numbers of type I and type II errors, and the second criterion the probabilities of type I and of type II errors. According to the first criterion A1 and A2 do not differ, generally. According to the second criterion A1 with the comparison of means of normal distributed variables is better than A2. Pooling of all p controls is better than A2 according to both criteria. A1 is better also according to the often used experimentwise type I error rate. The formulated criteria have some analogy to those of MILLER (1966). It may be possible to use them not only for comparing experimental arrangements but also tests.
The Median Test and Inhomogeneity of Slopes
Authors: Schlittgen R.
Published: April 2007

By some examples it is shown that the median test is not robust against deviations from homogeneity of slopes. It is also shown that it is not conservative if this assumption does not hold true.
Construction of Equi‐replicated Balanced Block Designs with Block Sizes Exceeding the Number of Treatments
Authors: Ceranka B. , Mejza S.
Published: April 2007

In this note it is shown that the block design with incidence matrix Ñ = [NN… N], where N = c1hNh + coh (11′–Nh). coh and c1h are any non‐negative integers and Nh,h = 1, 2,…,p, are incidence matrices of balanced incomplete block designs with the same number of treatments t, is a balanced block design with the block sizes exceeding the number of treatments. In derivation the matrix M0, introduced by CALIński (1971) is utilized.
Analyse des pedigrees et calcul des coefficients d'identité par les arbres géniques
Authors: Vu Khang J. Tien , de Rochambeau H. , Chevalet C. , Gillois M.
Published: April 2007

Two genes in a pedigree are identical by descent if they are two copies of a common ancestor gene. To obtain an unambiguous definition of the set of genes, at some autosomal locus, any gene is defined as an ordered pair of zygotes: the zygote who carries the gene, and the parent who transmitted it. The natural ordered structure on the set of zygotes yields an ordered structure upon the set of genes. Any event of the mendelian segregation splits down the set of genes into non‐overlaping classes of identical genes: when considered as an ordered sub‐set of genes, each class is shown to have the algebraic properties of a tree. Given a sub‐set 𝔗 of genes, a family of exclusive events ensuring identity between all genes of 𝔗 is identified as a family of genic trees with some property. This relationship between segregational events and genic trees is extended to the case where two sub‐sets 𝔗 and 𝔗′ of genes are considered together. As a consequence, a general method is obtained to compute either identity coefficients involving any number of genes splitted into one or two identity classes, or the fifteen coefficients defined among four genes, whichever the relationships between zygotes and genes might be. Using this approach to deal with the allelic structure in a set of genes carried by related zygotes is suggested.
Linear Discriminant Functions and Problems of Hybridization
Authors: Kabe D. G.
Published: April 2007

A discriminant analysis method for frequency data for hybridization based on weighted multivariate analysis of variance is given for allotting an individual to one of groups.
A Mathematical Model for Extrachromosomal Heredity in Somatic Cells, Exemplified by Liver Cells
Authors: Hopfenmüller W.
Published: April 2007

The cytoplasm of a zygote is observed on the somatic way of evolution up to the organ. For mitochondria, which are the most important cellcomponents for the extranuclear heredity, a model of evolution for liver cells with its computer programs was developed.
Four Applications of a Bivariate Pareto Distribution
Authors: Hutchinson T. P.
Published: April 2007

The following model, of “latent structure” type, is considered: in each subpopulation, X and Y are random variables drawn independently from the same exponential distribution, and the parameter of the exponential distribution varies between subpopulations with a Gamma density. Over the whole population, X and Y are then positively correlated, and jointly have a bivariate PARETO distribution. Four examples show how this distribution is useful in analysing ordered contingency tables in which the two dimensions can be regarded as alternative measures of the same thing: the injuries to the two drivers in a road accident, or the severity of a lesion present in a patient as assessed by two physicians, for instance.

Two extensions are considered: (a) allowing X and Y to have Gamma distributions, with each subpopulation having the same shape parameter but different scale parameters; (b) allowing the scale parameter for Y to be correlated with the scale parameter for X, rather than being identical to it. A new bivariate distribution with three shape parameters is derived, expressed in terms of a generalised hypergeometric function.
The Sensitivity of the Stationary Age Class Distribution o Changes in the Life History Components
Authors: Gregorius H.‐R.
Published: April 2007

The influence of the various components of the life history on the stationary age class distribution of a population was studied by applying the Leslie matrix model and then considering the single age class frequencies as well as the average age and the cumulative age class distribution in the stationary state.

Since, for fixed survival probabilities, the effects of the (age specific) fecundities were shown to be already expressed by the (ultimate) growth rate, this investigation was concentrated on the influence of the survival probabilities and the growth rate. After having supplemented some useful details concerning the dependence of the growth rate on the life history and introduction of the shift concept as an interpretation of cumulative distributions, the mathematical results could be given a biologically intelligible meaning:

An increase in the growth rate for fixed survival probabilities is followed by a shift of all age class frequencies to earlier ages. Whereas age specific changes in fecundity do not result in age specific changes in the stationary age class distribution, increases in survival up to and including age k, say, do exhibit such changes in that they cause a shift of age class frequencies at least from those ages exceeding k to earlier ages.
Group Divisible Second Order Rotatable Designs
Authors: Singh M.
Published: April 2007

The Group Divisible Rotatable (GDR) designs are the designs in which the factors get divided into groups such that for the factors within group, the designs are rotatable. In the present paper we have obtained a series of Group Divisible Second Order Rotatable designs, by decomposing the v‐dimensional space corresponding to v‐factors under consideration into three mutually orthogonal spaces. We have given the least squares estimates of the parameters, the analysis and construction of such designs.
Quantitative Equations for the Calculation of Ideal Values of Intra‐ and Extraerythrocyte Ion Contents of Human Blood after Addition of Roentgenographic Contrast Media
Authors: Jäger B. , Mangelsdorf R. , Bollmann G.
Published: April 2007

Normalized quantitative equations were derived to permit the calculation of intra‐ and extra‐erythrocyte ionic contents of human blood following the in vitro application of contrast media. These formulae allow the ionic contents to be computed, which should be present in plasma and erythrocytes if, after contrast medium administration, no ionic shifts occur other than electrolyte unbalance as induced by changes in water content. The equations are also applicable when other aqueous solutions are added to human blood.
A Note Concerning “Some Nonparametric Tests of Predicted Order”
Authors: Hsu L. M.
Published: April 2007

SARRIS and WILKENING (1977) have recently proposed some non‐parametric trend tests, which they view as extensions of MOSTELLER'S test of predicted order. The present paper notes some errors in SARRIS and WILKENING's determination of significance levels for these tests, and describes how these errors may be corrected.
Bivariate Sign Tests Sensitive to Homeo‐ and Heteropoetic Treatment Effects
Authors: Kohnen R. , Lienert G. A.
Published: April 2007

Starting fromNpaired differences of a continuous variable, BENNETT's (1962) bivariate sign test is identified as a test against so called homeopoetic treatment effects (or location shifts in one or both variablesXandY). As a complement, a new sign test is identified to be sensitive to so called heteropoetic treatment effects (shifts in dispersion). Both tests are shown to be important in biomedical and psychosocial research. A numerical example is given from psychopharmacology using the new bivariate sign test.
On the estimation of mean parameter with random number of observations on each unit
Authors: Singh M. , Gupta V. K.
Published: April 2007

In this paper an attempt has been made to estimate the population parameter, mean, of a normal population when the number of observations taken on each unit is a random variable and is supposed to follow a Truncated POISSON Distribution.
Basic distribution theory for nonparametric gini‐like measures of location and dispersion
Authors: Heilmann W. ‐R.
Published: April 2007

In the present paper, the distributional properties of two nonparametric estimators of location and dispersion which are patterned after GINI'S “media differenza”, are studied. Since these are special U‐statistics, we can make use of known results to some extent. By some computed examples, the differences to the mean value and the standard deviation become apparent.
An empirical regression inequality
Authors: Kaigh W. D.
Published: April 2007

A descriptive inequality similar to the empirical CHEBYSHEV inequality concerning residuals in linear regression analysis is developed.
C. R. Rao's minque under four two‐way anova models
Authors: Kleffe J.
Published: April 2007

This paper presents C. R. RAO'S MINQUE along with their sample variances under four normal two‐way ANOVA models. The resulting formulae are similar to the ANOVA sums of squares, equally easy to handle with and may also serve to calculate restricted maximum likelihood estimates in a highly efficient way.
On connectedness of ordinary two‐way elimination of heterogeneity designs
Authors: Baksalary J. K. , Kala R.
Published: April 2007

For certain subclasses of ordinary, not necessarily equireplicated, two‐way elimination of heterogeneity designs, necessary and sufficient conditions are established for row connectedness and column connectedness of a design to imply its connectedness. The criteria obtained strengthen earlier results pertaining to this problem.
A model‐independent approach to the theory of experimental designs and a special discussion of bib. i general definition and designs with one or two block factors
Authors: örfer G. Herrend , Rasch D.
Published: April 2007

Experimental designs are definded by introducing an assignment matrix Z. It is shown by block designs and double block designs that using Z or an operator on Z otherwise defined, well known designs can be got as special cases. Till now we didn' find an experimental design which could not be defined by our matrix Z. The definitions of properties of experimental designs can be given independently of the model of the statistical analysis. This is shown for the property of balance of block designs.
On the mean square error associated with adaptive generalized ridge regression
Authors: McLachlan G. J.
Published: April 2007

Some numerical results are presented for generalized ridge regression where the additive constants are based on the data. The adaptive estimator so obtained is compared with the least‐squares estimator on the basis of mean square error (MSE). It is shown that the MSE of each component of the vector of ridge estimators may be as low as 47.1% of the variance of the corresponding component of the least squares vector or as high as 125.2%.
Estimation of random regression parameters
Authors: Wimmer G.
Published: April 2007

The problem of the best linear unbiased estimation (BLUE) of random regression parameters is considered. It is proved that increasing informations about the mean value of the parameters both extend the class of estimable linear functionals and improve on the estimation. In all investigated cases the uniqueness of BLUE is proved. In the case of known mean values the BLUE is shown to be numerically equivalent with the MMSEE almost everywhere. A numerical example shows the improvements of BLUE due to increasing informations about the mean values of the parameters.
Tests for profile analysis of paired curves based on friedman ranking methods
Authors: Lehmacher W.
Published: April 2007

Two nonparametric tests are proposed for the comparison of a paired sample of response curves with T congruent time points. The first procedure rank transforms each curve and tests the homogeneity of the resulting pair of averaged rank vectors. The second procedure rank transforms each pair of curves and tests the homogeneity of the related pair of averaged rank vectors. The first test detects only pure interactions; the second test checks if any difference exists between the rank curves. Both tests are presented in finite and asymptotic as well as in combined (by T singular tests) and multivariate form.
Estimating transition probabilities of singly and doubly stochastic matrices
Authors: Kabe D. G.
Published: April 2007

Vector quadratic programming techniques, based on the classical theory of vector quadratic forms, subjected to linear restrictions, minimization techniques are applied to the estimation of the transition probabilities of singly and doubly stochastic matrices.
On a stochastic model of a molecular genetic system capable of differentiation and reproduction of the initial state
Authors: Tchuraev R. N.
Published: April 2007

A model of the system, consisting of a cyclic 3‐operonic subsystem, related to a 2‐operonic trigger by direct and feedback connections, is built. The operons of this system are functionally connected by repressers. The basic postulates are: a) the repressers are stable; b) during cell division each molecule of represser and respective mRNA has equal probability to find itself in any daughter cell. Computer simulation demonstrates that after few cell divisions, analogues of somatic cell, maintaining the system for some successive divisions, and of generative cells, where by the system returns to the initial state, appear. A scheme of molecular genetic control system, producing a lot of different cell types in course of successive cell divisions, is proposed.
A model of niche overlap and interaction in ecological systems
Authors: Steinmüller K.
Published: April 2007

Ecological niches are the result of ecosystem element (compartment) interaction under the influence of environmental factors. The competence model is devised to map this interaction. It includes the assumption of an overall physiological state of a compartment depending only on intensive environmental factors, expressions for the adaptedness and competence of the compartment in interaction. Consequently, niches are environmental factor domains of superior competence. The situation of niches (niche structure) and competence maxima are extensively studied in the fundamental case of two interacting compartments and in the special case of n concentric compartments. The impact of one immigrating compartment is discussed. All detailed investigations made involve only one intensive environmental factor and the special assumption of similar physiological state functions of all compartments.
An intrinsic rank test for k independent samples
Authors: Kannemann K.
Published: April 2007

Considerations on the sensitivity of the KRUSKAL‐WALLIS Analysis of Variance by Ranks suggest an alternative method that is less sensitive to spurious interchange of ranks and tied ranks yet offers sufficient power. The Intrinsic Rank Test for k Independent Samples is proposed in this sense as an alternative method to the KRUSKAL‐ WALLIS test. The Intrinsic Rank Test is based on rank information, but the criterion ranks (intrinsic ranks) are not directly derïved from the observations, but rather indirectly, by means of a further transformation, from the ordinal ranks assigned in the usual manner. The incidence of the intrinsic ranks upon the k samples is then used to calculate a X2‐like test statistic, which is readily evaluated with the Gamma distribution.
A contribution to spline‐regression
Authors: Dathe E. M. , Müller P. H.
Published: April 2007

Considered are polynomial spline‐regressions by which functions with individual behaviour over parts of their domain may be approximated (in square mean) in a favourable manner by successive polynomials. Concerning the connections of the individual polynoms different conditions may be imposed as to continuity and smoothness. Beside of the calculation of the regression parameters essential results are the construction of confidence regions for the regression function and the formulation of tests for special dependence. Hints for practical application are given and a concrete example from agriculture is presented.
Estimation of regression models under linear restrictions
Authors: Srivastava V. K. , Agnihotri B. S.
Published: April 2007

The variance‐covariance matrices of restricted regression and mixed regression estimators are compared and the consequences of introducing variability in the restrictions are examined.
A bivariate median test
Authors: Bedall F. K. , Zimmermann H.
Published: April 2007

A bivariate median test is proposed which makes use of the geometric median or mediancentre. Simulations have shown that the resulting test statistic is X2‐distributed. The test may be extended to more than two groups, but not to more than two variates.
On classifying observations when one population is a mixture of normals
Authors: Lachenbruch P. A. , Broffitt B.
Published: April 2007

Some simple models for the mixture of distribution problems are considered. Two possible alternatives to the rather complex optimal discriminant function rule are mentioned. The performance of the BC method is never as satisfactory as the QDF method and in some cases it is far worse than the QDF method. The QDF can be used whenever sufficient numbers of observations are available to provide reasonably good estimates of means and covariances.
A concept of a general computer program for the iterative calculation of maximum likelihood estimators with application to qualitative dose response analyses
Authors: Pahnke K. , Stucky W.
Published: April 2007

In this article we describe the construction of a general computer program for the iterative calculation of maximum likelihood estimators. The program is general in the sense that it allows the maximization of any given likelihood function. The user only has to write a subroutine LKLHD, in which the special likelihood function and their first and second derivatives will be calculated. This subroutine is an input parameter of the optimization program. This enables the user to employ one main program for the maximization of various likelihood functions. This advantage will be shown for the evaluation of qualitative dose response relationships (quantal assays: probit‐, logit‐analysis).
Point estimation in quantal response models
Authors: Schumacher M.
Published: April 2007

In this article least‐squares‐ and maximum‐likelihood‐estimators in quantal response models are presented in a standardized terminology. The large sample properties are derived and the convergence properties of the Newton‐Raphson‐ and the Scoring‐method for the iterative solution of the likelihood equations are investigated. Finally, it is shown that the iterative least‐squares estimation methods are equivalent to the method of scoring.
Use of the tetrachoric correlation model in assessing clinical tests
Authors: Bennett B. M.
Published: April 2007

Categorical data on n patients are classified according to the results on an initial clinical test T, and also with respect to a subsequent and definitive diagnosis D. In this paper the sensitivity (=), specificity (=) and predictive values (=v) are discussed with reference to the tetrachoric correlation model based on the bivariate normal density (e.g. PEARSON, 1901; KENDALL and STUART, 1972, II, p. 317). The result of HAMDAN (1970) concerning the equivalence of the tetrachoric rt and the maximum likelihood estimate of the correlation coefficient is utilized in this paper to obtain a test of significance concerning rt, and also the relation between the tetrachoric function w and the relative risk ψ for the 2X2 table.
Direct chemiluminescence determination of ibuprofen by the enhancement of the KMnO4–sulphite reaction
Authors: Li Yinhuan , Lu Jiuru
Published: April 2007

A simple, rapid, flow‐injection chemiluminescence (CL) method is described for the determination of ibuprofen. A strong CL signal was detected when a mixture of the analyte and sulphite was injected into acidic KMnO4. The CL signal is proportional to the concentration of ibuprofen in the range 0.1–10.0 mg/L. The detection limit is 0.02 mg/L ibuprofen, the relative standard deviation is 1.8% (0.5 mg/L ibuprofen; n = 11) and the sample measurement frequency is 120/h. The proposed method was successfully applied to the determination of ibuprofen in pharmaceutical preparations and in spiked urine samples. The mechanism of the CL reaction is also discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitative determination of bilirubin by inhibition of chemiluminescence from lucigenin
Authors: Lee Hyun Sook , Karim Mohammad Mainul , Alam Seikh Mafiz , Lee Sang Hak
Published: April 2007

Bilirubin is a metabolic breakdown product of blood haem, of great biological and diagnostic importance. A new chemiluminescence (CL) method has been developed for the quantification of bilirubin. The method is combined with the flow injection analysis (FIA) technique and based on the inhibition effect of bilirubin on the CL from the lucigenin–hydrogen peroxide system in an alkaline medium. Under the optimum conditions, the decreased CL intensity was proportional to the concentration of bilirubin, in the range 0.0585–58.47 µg/mL. The detection limit estimated from the calibration graph was about 7.8826 ng/mL. The relative standard deviation (RSD) of 10 parallel measurements (1 × 10−4 mol/L bilirubin) was 2.5%. Recoveries of bilirubin were found to fall in the range 94–97.5% using control sera. The method is interference‐free, fast and easy to carry out. Copyright © 2007 John Wiley & Sons, Ltd.
Flow‐injection–electrochemical oxidation fluorimetry for determination of methotrexate
Authors: Chen Suming , Zhang Zhujun , He Deyong , Hu Yufei , Zheng Huzhi , He Chao
Published: April 2007

A novel fluorimetric model of on‐line electrochemical oxidation for the determination of methotrexate (MTX) is described in this paper. The method was based on the oxidation of MTX to a highly fluorescent product, 2,4‐diaminopteridine‐6‐carboxylic acid, by constant potential in the electrochemical oxidation flow cell. Stopped‐flow techniques were employed. Under optimal conditions, the fluorescence intensity of 2,4‐diaminopteridine‐6‐carboxylic acid was measured at excitation and emission wavelengths of 380 and 465 nm, respectively. The calibration graph was linear over concentrations of methotrexate in the range 2.0 × 10−7–1.0 × 10−5 g/mL, with a detection limit of 5.2 × 10−8 g/mL (3σ). The method has been successfully applied to the determination of methotrexate in human urine samples and showed a percentage recovery in the range 94.3–102.5%. Copyright © 2007 John Wiley & Sons, Ltd.
The effect of high‐temperature annealing on optical properties of porous anodic alumina formed in oxalic acid
Authors: Li Zhaojian , Huang Kelong
Published: April 2007

Photoluminescence (PL) of anodic alumina membranes (AAMs) with ordered nanopore arrays fabricated in oxalic acid has been investigated under different annealing temperatures. X‐ray diffraction reveals the structural transition from the amorphous state to crystallization. PL measurements show that a blue PL band occurs in the wavelength range 300–600 nm. The differential thermal analysis (DTA) and thermogravimetric analysis (TG) results revealed plentiful oxalic ions incorporated into the prepared AAMs. The PL band of AAMs could be attributed to the co‐actions of the oxygen vacancies (F+ and F centres) and the luminescent centres transformed from oxalic impurities. With the increase of the annealing temperature, the intensities of PL increase first, and at 500°C reach a maximum value, then decrease. The PL phenomenon is intimately related to the temperature‐induced structural transitions. There are three optical centres in the annealed AAMs; the first is originates from the F centres, the second is correlated with F+ centres and the third is associated with the oxalic impurities incorporated in the AAMs. Copyright © 2007 John Wiley & Sons, Ltd.
A flow‐injection chemiluminescence method for the determination of human serum albumin, using the reaction of fluorescein–human serum albumin–sodium hypochlorite by the enhancement effect of the cationic surfactant cetyltrimethylammonium bromide
Authors: Huang Chun‐Bao , Zhang Kai , Liu Xue‐Lian , Wang Sheng‐Fu
Published: April 2007

The interaction between surfactant and fluorescein was studied, using a fluorescence spectroscopy and flow‐injection (FI) chemiluminescence (CL) method. It was found that the cationic surfactant cetyltrimethylammonium bromide (CTAB) could cause the structural transformation of fluorescein from the quinone to the spirolactone form, and greatly enhance the CL intensity of the fluorescein–human serum albumin (HSA) complex. Based on this finding, a rapid and sensitive FI–CL method was developed for the determination of HSA. Under the optimum conditions, the proposed method has a linear range of 0.05–24.0 µg/mL, with a detection limit of 0.03 µg/mL for HSA (3σ). The relative standard deviation (RSD) of 1.2 µg/mL HSA (n = 8) is 0.8%. The method was applied to the determination of protein content in urine samples, with satisfactory results. Density functional theory was used to study the mechanism of surfactant‐enhanced CL intensity of the fluorescein–HSA complex. Copyright © 2007 John Wiley & Sons, Ltd.
A fluorimetric method for the determination of trace pentachlorophenol, based on its inhibitory effect on the redox reaction between the improved Fenton reagent and rhodamine B
Authors: Guo Huiqin , Fan Jing , Guo Yanhui
Published: April 2007

A sensitive fluorimetric method is presented and discussed for the determination of pentachlorophenol in aqueous solutions. This method is based on the inhibitory effect of pentachlorophenol on the reaction of conventional Fenton [Fe(III) + H2O2] reagent with rhodamine B in the medium of perchloric acid, which results in the fluorescence quenching of rhodamine B. It was further found that the sensitivity for the determination was improved significantly when the molecular ligand EDTA was added. This improved system was therefore presented for the determination of pentachlorophenol. The characteristics of the excitation and emission spectra, optimization of the experimental conditions, the stability of the system and the influence of foreign matter have all been investigated. Under optimal conditions, the linear range for the determination of pentachlorophenol is 12–480 ng/mL with a 3σ limit of detection of 0.96 ng/mL. Compared with the conventional Fenton system, the improved system shows obvious advantages in both sensitivity and selectivity. By combination with the pretreatment of samples using ion exchange resins and XDA‐1 absorption resin, the improved Fenton method was used for the first time for the determination of pentachlorophenol in synthetic samples and natural water samples, and satisfactory results, in agreement with those of the HPLC method, were achieved. The possible mechanism of the reactions has also been discussed. Copyright © 2007 John Wiley & Sons, Ltd.
CT evaluation of the vidian canal localization
Authors: Yazar Fatih , Cankal Fatih , Haholu Aptullah , Kiliç Cenk , Tekdemir Ibrahim
Published: April 2007

The primary purpose of our work is to show that the vidian canal can be determined on CT imaging. The secondary goal is to establish the position and configuration of the vidian canal visualization. The CT imaging of vidian canals of 150 patients were examined in axial and coronal sections in 3 mm thickness made at 3 mm intervals. The varying course of the canal inside the bone, bone structure and diameter of the canal were investigated. In all cases, the canal was seen, and in 4 of the cases (1.3%) the canal was separated into two parts by a septum on its initial portion. In 36% of the cases it was embedded in the sphenoid corpus, partially protruded in 54% of the cases, and was connected to the bone with a stalk inside the sinus in 10% of the cases. The bony structure of the canal showed continuation in 68%, with 32% showing dehisans. The incidence of dehisans was 77% in the stalked cases and 45% in the protruded cases. It was determined that it is possible to evaluate the position and configuration of the vidian canal with CT imaging. This may be useful for diagnosing vidian nerve pathology and performing surgical intervention such as vidian neuroectomy and sinus surgery. Clin. Anat. 20:751–754, 2007. © 2007 Wiley‐Liss, Inc.
A Multiplexed Protein Kinase Assay
Authors: Shults Melissa D. , Kozlov Igor A. , Nelson Nicholas , Kermani Bahram G. , Melnyk Peter C. , Shevchenko Veronika , Srinivasan Anu , Musmacker Joseph , Hachmann John P. , Barker David L. , Lebl Michal , Zhao Chanfeng
Published: April 2007

We report a novel protein kinase assay designed for high‐throughput detection of one or many kinases in a complex mixture. A solution‐phase phosphorylation reaction is performed on 900 different peptide substrates, each covalently linked to an oligonucleotide tag. After incubation, phosphoserine, phosphothreonine, and phosphotyrosine are chemically labeled, and the substrates are hybridized to a microarray with oligonucleotides complementary to the tags to read out the phosphorylation state of each peptide. Because protein kinases act on more than one peptide sequence, each kinase can be characterized by a unique signature of phosphorylation activity on multiple substrates. Using this method, we determined signatures for 26 purified kinases and demonstrated that enzyme mixtures can be screened for activity and selectivity of inhibition.
Calix[4]arene‐Based Bis[2]catenanes: Synthesis and Chiral Resolution
Authors: Molokanova Olena , Bogdan Anca , Vysotsky Myroslav O. , Bolte Michael , Ikai Tomoyuki , Okamoto Yoshio , Böhmer Volker
Published: April 2007

The exclusive formation of hydrogen‐bonded dimers between tetraaryl and tetratosylurea calix[4]arenes has been used to prepare a series of ten “bisloop” tetraurea calix[4]arenes 3, in which adjacent phenylurea groups are covalently linked through α,ω‐dioxyalkane chains. This dimerization with tetratosylurea 2 as template preorganizes the alkenyl residues of tetra(m‐alkenyloxyphenyl) ureas 1 and enables their selective connection in high yield (up to 95 %) by olefin metathesis followed by hydrogenation. The “bisloop” calixarenes 3 also exclusively form heterodimers with 1. Thus, in a separated metathesis/hydrogenation sequence, a series of 14 cyclic bis[2]catenanes 4, in which two calix[4]arenes are connected through their wide rims by two pairs of interlocked rings (total size 29 to 41 atoms), were prepared in yields of up to 97 %. Optical resolution of these chiral bis[2]catenanes was studied by HPLC on chiral stationary phases. The single‐crystal X‐ray structure of one example (4(P,10)) confirmed the interlocking rings and revealed that the hydrogen‐bonded dimeric capsule of the calix[4]arene can be “completely” opened.
Cover Picture: Ensemble‐Docking Approach on BACE‐1: Pharmacophore Perception and Guidelines for Drug Design (ChemMedChem 5/2007)
Authors: Limongelli Vittorio , Marinelli Luciana , Cosconati Sandro , Braun Hannes A. , Schmidt Boris , Novellino Ettore
Published: April 2007

The cover picture shows a model of the BACE‐1 enzyme represented in ribbon mode with the catalytic site highlighted as a grey Connolly surface. The binding site is filled with six BACE‐1 inhibitors in their docked conformations and coloured according to conserved interaction points. Theoretical studies of inhibitor binding allowed us to delineate an exhaustive nine‐point pharmacophore model (upper right), which captures both the common geometric and the electronic features essential for enzyme inhibition. Interestingly, five of these points are present in all the inspected ligands (blue spheres), thus they can be referred to as essential features for inhibitor recognition and binding, whereas the other four points (light‐blue spheres) contribute to BACE‐1 selective inhibition. For more details, see the Full Paper by L. Marinelli et al. on p. 667 ff.
On the convergence and singularities of the J‐Flow with applications to the Mabuchi energy
Authors: Song Jian , Weinkove Benjamin
Published: April 2007

The J‐flow of S. K. Donaldson and X. X. Chen is a parabolic flow on Kähler manifolds with two Kähler metrics. It is the gradient flow of the J‐functional that appears in Chen's formula for the Mabuchi energy. We find a positivity condition in terms of the two metrics that is both necessary and sufficient for the convergence of the J‐flow to a critical metric. We use this result to show that on manifolds with ample canonical bundle, the Mabuchi energy is proper on all Kähler classes in an open neighborhood of the canonical class defined by a positivity condition. This improves previous results of Chen and of the second author. We discuss the implications of this for the problem of the existence of constant‐scalar‐curvature Kähler metrics.

We also study the singularities of the J‐flow and, under certain conditions (which always hold for dimension 2) derive some estimates away from a subvariety. We discuss the conjectural remark of Donaldson that if the J‐flow does not converge on a Kähler surface, then it should blow up over some curves of negative self‐intersection. © 2007 Wiley Periodicals, Inc.
Blowup for nonlinear wave equations describing boson stars
Authors: Fröhlich Jürg , Lenzmann Enno
Published: April 2007

We consider the nonlinear wave equation

modeling the dynamics of (pseudorelativistic) boson stars. For spherically symmetric initial data, u0(x) ∈ C (ℝ3), with negative energy, we prove blowup of u(t, x) in the H1/2‐norm within a finite time. Physically this phenomenon describes the onset of “gravitational collapse” of a boson star. We also study blowup in external, spherically symmetric potentials, and we consider more general Hartree‐type nonlinearities. As an application, we exhibit instability of ground state solitary waves at rest if m = 0. © 2007 Wiley Periodicals, Inc.
Hamiltonian ODEs in the Wasserstein space of probability measures
Authors: Ambrosio Luigi , Gangbo Wilfrid
Published: April 2007

In this paper we consider a Hamiltonian H on 𝒫2(ℝ2d), the set of probability measures with finite quadratic moments on the phase space ℝ2d = ℝd × ℝd, which is a metric space when endowed with the Wasserstein distance W2. We study the initial value problem dμt/dt + ∇ · (𝕁dvtμt) = 0, where 𝕁d is the canonical symplectic matrix, μ0 is prescribed, and vt is a tangent vector to 𝒫2(ℝ2d) at μt, belonging to ∂H(μt), the subdifferential of H at μt. Two methods for constructing solutions of the evolutive system are provided. The first one concerns only the case where μ0 is absolutely continuous. It ensures that μt remains absolutely continuous and vt = ∇H(μt) is the element of minimal norm in ∂H(μt). The second method handles any initial measure μ0. If we further assume that H is λ‐convex, proper, and lower‐semicontinuous on 𝒫2(ℝ2d), we prove that the Hamiltonian is preserved along any solution of our evolutive system, H(μt) = H(μ0). © 2007 Wiley Periodicals, Inc.
Loop Spaces and the hypoelliptic Laplacian
Authors: Bismut Jean‐Michel
Published: April 2007

The purpose of this paper is to introduce some ideas that motivated the construction of the hypoelliptic Laplacian as a deformation of Hodge theory, which interpolates between Hodge theory and the geodesic flow. Results obtained with Lebeau on the analysis of the hypoelliptic Laplacian are also presented. © 2007 Wiley Periodicals, Inc.
A Comparative Study on the Photochemistry of Two Bipyridyl Derivatives: [2,2′‐Bipyridyl]‐3,3′‐diamine and [2,2′‐Bipyridyl]‐3,3′‐diol
Authors: Ortiz‐Sánchez Juan Manuel , Gelabert Ricard , Moreno Miquel , Lluch José M.
Published: April 2007

The two isoelectronic bipyridyl derivatives, [2,2′‐bipyridyl]‐3,3′‐diamine and [2,2′‐bipyridyl]‐3,3′‐diol, are experimentally known to undergo very different excited‐state double‐proton‐transfer processes, which result in fluorescence quantum yields that differ by four orders of magnitude. Herein, density functional theory (DFT), time‐dependent DFT (TDDFT), and complete active space self‐consistent field (CASSCF) calculations are used to study the double‐proton‐transfer processes in the ground and first singlet π→π* excited state. The quantum‐chemistry calculations indicate 1) the existence of only one energy minimum in the ground electronic state corresponding to reactants (thus avoiding the possibility of a fast fluorescent relaxation process from the photoproducts region), 2) an endoergic process of the complete double proton transfer, and 3) the presence of a conical intersection in the excited intermediate region of [2,2′‐bipyridyl]‐3,3′‐diamine. These facts explain the very low fluorescence quantum yield in [2,2′‐bipyridyl]‐3,3′‐diamine compared to [2,2′‐bipyridyl]‐3,3′‐diol.
Inter‐organizational use of EMSs in supply chain management: some experiences from Poland and Sweden
Authors: Nawrocka Dagmara
Published: April 2007

The paper investigates the possibility of using environmental management systems (EMSs) as a tool for the environmental management of supply chains. Based on interviews with environmental managers of selected companies, the paper highlights the importance of taking a long‐term perspective in terms of both the cooperation with suppliers and developing the supply chain perspective for EMSs. The role of cultural influence from foreign partner companies in building the proactive environmental focus and stimulating the spread of EMSs is underlined here. In addition, the paper looks at the development, use and control of supply chain environmental requirements and their possible integration into the buyer's and supplier's EMSs. Finally, important shortcomings of EMSs, such as the lack of enforcement forbearance and the credibility of ISO 14001 certification, are discussed. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment.
Sinistral equal‐size spiral cleavage of the indirectly developing polychaete Hydroides elegans
Authors: Arenas‐Mena Cesar
Published: April 2007

Two major variants of the stereotypic spiral cleavage correlate with distinct developmental modes in polychaetes. Indirect development through a feeding trochophore larva correlates with development from four equal‐sized blastomeres, whereas direct development correlates with unequal cleavage characterized by a large dorsal blastomere precursor maternally predetermined. The equal‐size spiral cleavage of the indirectly developing serpulid Hydroides elegans has been reconstructed from serial sections of nuclei‐stained embryos. The order of cell divisions has been determined from the 2‐cell stage to the 80‐cell stage, when gastrulation cell movements start to overlap with late spiral‐cleavage divisions. In contrast to related species, the third cleavage in Hydroides elegans is invariably sinistral. The four quadrants remain indistinct until the 60‐cell stage, when the small 2d22 and large 2d21 cells are generated. The developmental significance of the invariant spiral cleavage relates to the spatial distribution of gene functions that it partitions and their relation to blastomere fate commitments. The conservation and divergence of the cleavage pattern among spiralians is well suited to study the developmental control of the cell‐cleavage machinery and its evolution. Developmental Dynamics 236:1611–1622, 2007. © 2007 Wiley‐Liss, Inc.
Electronic Structure of Linearly Coordinated EQ Complexes of the Type [(N3N)W(EQ)] [N3N = N(CH2CH2NSiMe3)3; E = P, As, Sb, Bi; Q = O, S, Se, Te]: A DFT Study
Authors: Balázs Gábor , Green Jennifer C. , Mingos D. Michael P.
Published: April 2007

Density functional theory (DFT) calculations were carried out on the terminal EQ complexes [(N3N)W(EQ)] {N3N = N(CH2CH2NSiMe3)3; E = P, As, Sb, Bi; Q = O, S, Se Te} to clarify the bonding situation within the linear Nax–W–E–Q core. This unusual structural motif gives rise to a bonding arrangement in which the π‐electron density is delocalised over the three atoms of the W–E–Q unit. Fragment calculations and natural bond order (NBO) data indicated that the σ‐bonding component of the Nax–W–E–Q unit comprises two occupied σ orbitals, while the π component of bonding comprises two sets of degenerate π orbitals. In general, the π orbitals of the Nax–W–E–Q core are higher in energy compared to the σ orbitals. The phosphorus monoxide (EQ = PO) complexes provide an exception to this rule, with the 1π orbitals of the W–P–O core lower in energy than the σ orbitals. Generally, as the atomic number of either the pnicogen (E) or chalcogen (Q) atom increases the extent of σ‐orbital delocalisation decreases, whereas the π‐orbital delocalisation increases. Fractional bond orders and Wiberg bond indices were used to establish whether localisation of the π‐electron density gives rise to a W–E or an E–Q double or triple bond. Both methods indicate a W–E as well as an E–Q double bond. The ionic nature of the complexes were analysed by inspection of the Hirschfeld charge distribution which shows only a moderate ionic character. Exceptions are the pnicogen monoxide complexes, which are more ionic. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Dendritic Host Molecules with a Polycationic Core and an Outer Shell of Dodecyl Groups
Authors: van de Coevering Rob , Bruijnincx Pieter C. A. , van Walree Cornelis A. , Klein Gebbink Robertus J. M. , van Koten Gerard
Published: April 2007

The synthesis of a topologically new type of dendrimer is presented in which a permanently positively charged core is decorated with a shell that is apolar and aliphatic in nature. The novel polyionic dendrimers were successfully applied as hosts for a predefined number of anionic guests, as is shown for the dye methyl orange. The aliphatic periphery of the dendrimers efficiently shields the ion pairs and renders the dendrimers fully soluble in organic solvents that are as apolar as hexane and, furthermore, provides them with an interesting phase behavior that appears not to be sensitive to the type of anion associated with it.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of Enantiopure 1‐Azaspiro[4.5]decanes by Iodoaminocyclization of Allylaminocyclohexanes
Authors: Diaba Faïza , Puigbó Gemma , Bonjoch Josep
Published: April 2007

The 5‐endo iodine‐promoted ring closure of 4‐allyl‐4‐(alkylamino)cyclohexanone derivatives gives the corresponding 1‐azaspiro[4.5]decanes in good yields. The reaction was tested with enantiopure homoallylamines to evaluate the diastereoselectivity of the process and to provide a route for possible intermediates to the natural products embodying this azabicyclic ring.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Die Kultur, der Kommerz und das Image
Authors: Kaschuba Wolfgang , Färber Alexa , Gdaniec Cordula
Published: April 2007

Theater und Kunst, Musikszenen oder Subkulturen sind zu einem „harten”︁ Standortfaktor für Metropolen geworden. Kulturwissenschaftler untersuchen am Beispiel von Berlin und Moskau, wie aus Kultur Kapital gemacht wird
Den Schadstoffen auf der Spur
Authors: Unterstell Rembert
Published: April 2007

Zwischen Grundlagenforschung und Politikberatung: Helmut Greim, langjähriger Vorsitzender der MAK‐Kommission, zieht Bilanz
Im Kampf gegen die Malaria
Authors: Müller Olaf
Published: April 2007

Jährlich sterben bis zu drei Millionen Menschen an dieser Infektionskrankheit. Die Verwendung von Moskitonetzen kann ein effektiver Schutz sein
No excess risk for colorectal cancer among subjects seropositive for the JC polyomavirus
Authors: Lundstig Annika , Stattin Pär , Persson Kenneth , Sasnauskas Kestutis , Viscidi Raphael P. , Gislefoss Randi Elin , Dillner Joakim
Published: April 2007

The human polyomaviruses JC virus (JCV) and BK virus (BKV) are oncogenic in experimental systems and commonly infect humans. JCV DNA has been reported to be present in human colon mucosa and in colorectal cancers. To investigate whether the risk for colorectal cancer is associated with JCV or BKV infection, we performed a case–control study nested in the Janus biobank, a cohort of 330,000 healthy Norwegian subjects. A 30‐year prospective follow‐up using registry linkages identified 386 men with colorectal cancer who had baseline serum samples taken >3 months before diagnosis. Control subjects were matched for sex, age and date of blood sampling and county of residence. Seropositivity for JCV or BKV had high (97–100%) sensitivity for detection of viral DNA‐positive subjects and discriminated the different polyomaviruses. Seropositivity was mostly stable over time in serial samples. The relative risk for colorectal cancer among JCV seropositive subjects was 0.9 (95% CI: 0.7–1.3) and the BKV‐associated relative risk was 1.1 (95% CI: 0.8–1.5). Determining seropositivity using alternative cutoffs also found no evidence of excess risk. In summary, this prospective study found no association between JCV or BKV infections and excess risk for colorectal cancer. © 2007 Wiley‐Liss, Inc.