bluuebunny/crossref_metadata_2025_split huggingface dataset:
Palladium(II) Complexes with Phosphanylferrocenecarboxylate Ligands and Their Use as Catalyst Precursors for Semialternating CO–Ethylene Copolymerization
Authors: Bianchini Claudio , Meli Andrea , Oberhauser Werner , Segarra Anna Maria , Passaglia Elisa , Lamač Martin , Štěpnička Petr 
Published: November 2007

AbstractNeutral [Pd(κP,κO‐P~O)(κ3C,C,C‐carbocycloenyl)] complexes, where P~O is a chiral or achiral chelating phosphanylferrocenecarboxylate ligand, were synthesized and characterized by multinuclear NMR spectroscopy. The crystalstructure of a representative complex was determined by single‐crystal X‐ray diffraction analysis. In all complexes, the palladium(II) ion is located at the centre of a square plane formed by the P and O donor atoms from an anionic P~O– ligand, a σ‐carbon atom and a C–C double bond from a carbocycloenyl ligand. Neutral methyl complexes with the formulas [PdCl(Me)(κP,κH‐P~OH)] and [Pd(Me)(OTs)(κP,κH‐P~OH)] were also synthesized and characterized. On the basis of IR, NMR and MS–FAB data, the methyl complexes are proposed to be formulated with the fourth coordination position occupied by an agostic O–H···Pd interaction from a free carboxylic acid moiety [P~OH = 1′‐(diphenylphosphanyl)ferrocenecarboxylic acid] or a solvent molecule. Selected complexes were employed as catalyst precursors for CO–ethylene copolymerization in MeOH in the presence of an excess of p‐toluenesulfonic acid. In all cases, low molecular weight semialternating polyketones were produced. The catalytic activities were rather low and the extra‐ethylene insertion reached a maximum value of 4.3 %. An operando high‐pressure NMR experiment with [Pd(Me)(S)2(κP‐P~OH)]OTs (S = solvent, adventitious water) precursor showed that this monocationic PdII alkyl complex is readily converted into a catalytically inactive binuclear carbonyl‐bridged PdI compound, which, however, regenerates catalytically active PdII–H species by reaction with TsOH and that β‐chelates of the formula [Pd(CH2CH2C(O)P)(S)(κP‐P~OH)]OTs (P = propagating polyketone chain) are catalyst resting states. For the first time, β‐chelate propagating species have been intercepted in a CO–olefin copolymerization assisted by catalysts devoid of a chelating ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Complexes of Niobium(V) and Tantalum(V) Halides with Ligands that Contain N–C=O and P=O Functionalities: A Synthetic and Structural Study
Authors: Marchetti Fabio , Pampaloni Guido , Zacchini Stefano 
Published: November 2007

AbstractThe reactions of niobium and tantalum pentahalides, MX5, with dialkylureas (tetramethyl‐ and tetraethylurea, TMU and TEU, respectively), amides (N,N,dimethylformamide, DMF, N,N‐diethylformamide, DEF, N‐phenylacetamide, PhA), and P=O‐containing compounds (triphenylphosphane oxide, TPPO, and trimethyl phosphate, TMP) are not dependent on the reactant to metal molar ratio, and afford hexacoordinate complexes of the general formula MX5(L). The only exception is given by the reaction of TaBr5 with TMU, which proceeds by bromide migration from one metal center to another, and provides the ionic adduct [TaBr4(TMU)2][TaBr6]. Hydrolysis of TaCl5(TMP), due to adventitious water, has yielded the dinuclear species Ta2(μ‐O)Cl8(TMP)2. All compounds have been fully characterized in solution, and X‐ray crystal structures have been determined for NbCl5(TEU), NbCl5(DMF), TaCl5(DMF), TaCl5(PhA), TaBr5(PhA), TaCl5(TPPO), [TaBr4(TMU)2][TaBr6], and Ta2(μ‐O)Cl8(TMP)2. No evidence for formation of M=O bonds due to oxygen atom transfer from the ligand to the metal has been observed in any case. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Acid‐Induced and Reductive Transfor­mations of Enantiopure 3,6‐Dihydro‐2H‐1,2‐oxazines – Synthesis of Dideoxyamino Carbohydrate Derivatives
Authors: Bressel Bettina , Egart Boris , Al‐Harrasi Ahmed , Pulz Robert , Reißig Hans‐Ulrich , Brüdgam Irene 
Published: November 2007

AbstractAcid‐catalyzed transformations of carbohydrate‐derived 3,6‐dihydro‐2H‐1,2‐oxazines such as 1, 5 and 13 provided a set of enantiopure furano‐1,2‐oxazines or pyrano‐1,2‐oxazines. The reaction conditions determined the degree of solvolysis of the compounds. An X‐ray analysis of product 6 revealed an interesting network of hydrogen bonds. Reductive cleavage of the N–O bond of the 1,2‐oxazines either by hydrogen/palladium or by samarium diiodide furnished enantiopure aminofuran and ‐pyran derivatives, e.g. 9 and 11 or compound 16, which can be regarded as protected 4‐amino‐1,4‐dideoxyhex‐3‐ulose or 4‐amino‐1,4‐dideoxyoct‐3‐ulose derivatives. We thus have established a short and stereocontrolled route to amino carbohydrate derivatives with 1,2‐oxazines as crucial relay compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Early Carboniferous (Mississippian) calciturbidites in the northern Rhenish Mountains (Germany)
Authors: Korn D. 
Published: November 2007

AbstractViséan calciturbidites occur in two separate turbidite sequences at the northern margin of the Rhenish Mountains: (1) the Herdringen Sequence (Becke‐Oese, Retringen and Herdringen formations), and (2) the Hellefeld Sequence (Hellefeld, Linnepe and Wennemen formations). Both sequences show temporal fluctuations in the carbonate content, which can be related to global eustatic fluctuations. Two peaks of carbonate sedimentation which occurred during lowstands in the Holkerian to early Asbian and in the Brigantian are interrupted by a late Asbian decline of carbonate deposition during a transgressive interval. Patterns of bed thickness and carbonate content in the Herdringen Sequence indicate a sediment source to the north; it shifted during the Late Viséan from the northeast to the northwest. Coeval sediments in the Hellefeld Sequence were derived from a source to the southeast. Detailed analyses of Asbian sections show the high potential for fine‐scaled correlation. Copyright © 2007 John Wiley & Sons, Ltd.
Use of evidence in economic decision models: practical issues and methodological challenges
Authors: Cooper N. J. , Sutton A. J. , Ades A. E. , Paisley S. , Jones D. R. ,   on behalf of the working group on the ‘use of evidence in economic decision models’
Published: November 2007

AbstractThis paper outlines the current ‘state of play’ regarding the use of evidence in decision modelling and highlights both practical issues and methodological challenges related to identifying, combining and reporting evidence to inform decision model parameters and structure. Based on discussions at two MRC HSRC‐funded workshops consisting of 37 experts from a range of disciplines (i.e. decision‐makers, health economists, information specialists, operations researchers and statisticians), it aims to derive a multi‐disciplinary standpoint on the appropriate use of evidence in economic decision models and, where applicable, offer some suggestions for good modelling practice. Gaps in the established methodology knowledge base are identified for future research. Copyright © 2007 John Wiley & Sons, Ltd.
3D elastic scattering theorems for point‐generated dyadic fields
Authors: Athanasiadis C. E. , Sevroglou V. , Stratis I. G. 
Published: November 2007

AbstractThe problem of scattering of elastic spherical waves by a rigid body, cavity or a penetrable obstacle in 3D linear elasticity is considered. For two point sources, dyadic far‐field pattern generators are defined, which are used for the formulation of a general scattering theorem. The main reciprocity principle and mixed scattering relations are also established. We provide the necessary energy considerations, presenting relative energy functionals and expressions for the differential and the scattering cross section due to point‐source dyadic incidence. Finally, an application of the general scattering theorem for appropriate locations of the point source leads to an optical theorem. Copyright © 2007 John Wiley & Sons, Ltd.
A critical appraisal of propensity‐score matching in the medical literature between 1996 and 2003
Authors: Austin Peter C. 
Published: November 2007

AbstractPropensity‐score methods are increasingly being used to reduce the impact of treatment‐selection bias in the estimation of treatment effects using observational data. Commonly used propensity‐score methods include covariate adjustment using the propensity score, stratification on the propensity score, and propensity‐score matching. Empirical and theoretical research has demonstrated that matching on the propensity score eliminates a greater proportion of baseline differences between treated and untreated subjects than does stratification on the propensity score. However, the analysis of propensity‐score‐matched samples requires statistical methods appropriate for matched‐pairs data. We critically evaluated 47 articles that were published between 1996 and 2003 in the medical literature and that employed propensity‐score matching. We found that only two of the articles reported the balance of baseline characteristics between treated and untreated subjects in the matched sample and used correct statistical methods to assess the degree of imbalance. Thirteen (28 per cent) of the articles explicitly used statistical methods appropriate for the analysis of matched data when estimating the treatment effect and its statistical significance. Common errors included using the log‐rank test to compare Kaplan–Meier survival curves in the matched sample, using Cox regression, logistic regression, chi‐squared tests, t‐tests, and Wilcoxon rank sum tests in the matched sample, thereby failing to account for the matched nature of the data. We provide guidelines for the analysis and reporting of studies that employ propensity‐score matching. Copyright © 2007 John Wiley & Sons, Ltd.
A likelihood reformulation method in non‐normal random effects models
Authors: Liu Lei , Yu Zhangsheng 
Published: November 2007

AbstractIn this paper, we propose a practical computational method to obtain the maximum likelihood estimates (MLE) for mixed models with non‐normal random effects. By simply multiplying and dividing a standard normal density, we reformulate the likelihood conditional on the non‐normal random effects to that conditional on the normal random effects. Gaussian quadrature technique, conveniently implemented in SAS Proc NLMIXED, can then be used to carry out the estimation process. Our method substantially reduces computational time, while yielding similar estimates to the probability integral transformation method (J. Comput. Graphical Stat.2006;15:39–57). Furthermore, our method can be applied to more general situations, e.g. finite mixture random effects or correlated random effects from Clayton copula. Simulations and applications are presented to illustrate our method. Copyright © 2007 John Wiley & Sons, Ltd.
A discrete‐continuous mixture quantile function estimator with a practical application to phase II cancer clinical trials
Authors: Hutson Alan D. 
Published: November 2007

AbstractOftentimes in biological and clinical settings an underlying continuous variable or discrete‐continuous mixture is dichotomized in order to interpret the results in a simpler fashion. Tests of interest are then typically based on exact binomial tests. In this article, we illustrate the utility of a new quantile‐based approach towards testing the same basic scientific question in terms of improved relative efficiency and similar ease of interpretation when compared with the binomial test. We illustrate the utility of our approach with an eye towards mixtures of discrete‐continuous data commonly found in phase II cancer clinical trial data. Copyright © 2007 John Wiley & Sons, Ltd.
Coating selection and tribological testing for engineering equipment applications
Authors: Franklin S.E. 
Published: November 2007

AbstractThis paper considers the process of selecting and testing coatings for parts in professional engineering equipment applications in relation to the needs of design engineers in industry and the practical issues encountered. A methodology for pre‐selection of potential coating solutions is discussed and consideration is given to the practical implementation of testing strategies in order to obtain results that are pertinent to the application. Two example case studies are described and the results are discussed in terms of their practical relevance and use. Copyright © 2007 John Wiley & Sons, Ltd.
Neurological implications of urea cycle disorders
Authors: Gropman A. L. , Summar M. , Leonard J. V. 
Published: November 2007

SummaryThe urea cycle disorders constitute a group of rare congenital disorders caused by a deficiency of the enzymes or transport proteins required to remove ammonia from the body. Via a series of biochemical steps, nitrogen, the waste product of protein metabolism, is removed from the blood and converted into urea. A consequence of these disorders is hyperammonaemia, resulting in central nervous system dysfunction with mental status changes, brain oedema, seizures, coma, and potentially death. Both acute and chronic hyperammonaemia result in alterations of neurotransmitter systems. In acute hyperammonaemia, activation of the NMDA receptor leads to excitotoxic cell death, changes in energy metabolism and alterations in protein expression of the astrocyte that affect volume regulation and contribute to oedema. Neuropathological evaluation demonstrates alterations in the astrocyte morphology. Imaging studies, in particular 1H MRS, can reveal markers of impaired metabolism such as elevations of glutamine and reduction of myoinositol. In contrast, chronic hyperammonaemia leads to adaptive responses in the NMDA receptor and impairments in the glutamate–nitric oxide–cGMP pathway, leading to alterations in cognition and learning. Therapy of acute hyperammonaemia has relied on ammonia‐lowering agents but in recent years there has been considerable interest in neuroprotective strategies. Recent studies have suggested restoration of learning abilities by pharmacological manipulation of brain cGMP with phosphodiesterase inhibitors. Thus, both strategies are intriguing areas for potential investigation in human urea cycle disorders.
Pattern of beverage consumption and long-term association with body-weight status in German adolescents – results from the DONALD study
Authors: Libuda Lars , Alexy Ute , Sichert-Hellert Wolfgang , Stehle Peter , Karaolis-Danckert Nadina , Buyken Anette E. , Kersting Mathilde 
Published: November 2007

In the present study the relationship between the consumption of different beverage groups and body-weight status in 5 years of study participation in German adolescents was investigated. We used anthropometric and dietary data from 3 d weighed records of 244 subjects between 9 and 18 years of age participating in the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study. Only subjects with at least four out of six possible weighed dietary records were considered. A repeated-measures regression model (PROC MIXED) was used to analyse the effect of beverage consumption on body-weight status. BMI standard deviation scores (BMI-SDS) and body fat percentage (%BF) were chosen as the dependent variables. In boys, energetic beverage consumption was not associated with BMI-SDS or %BF, neither cross-sectionally nor prospectively. In girls, baseline consumption of energetic beverages did not predict baseline BMI-SDS, baseline %BF, or change in either variable over the study period. However, an increase in energetic beverage consumption over the study period was associated with an increase in BMI-SDS (+0.070 SDS/MJ increase in energetic beverage consumption; P = 0·01). Separate consideration of regular soft drinks and fruit juices revealed that, in girls, BMI-SDS increased with increased fruit juice consumption (+0·096 SDS/MJ increase in fruit juice consumption; P = 0·01), and to a lesser extent with regular soft drink consumption (+0·055 SDS/MJ increase in regular soft drink consumption; P = 0·08). In conclusion, these results suggest that an increase in energetic beverage consumption may result in weight gain, at least in adolescent girls.
OBITUARY
Authors: Anderson Ian 
Published: November 2007

Daniel Martin B.Sc., M.A., Ph.D., F.R.S.E. was born in Carluke on 16 April 1915, the only child of William and Rose Martin (née Macpherson). The family home in which he was born, Cygnetbank in Clyde Street, had been remodelled and extended by his father, and it was to be Dan's home all his life. His father, who was a carpenter and joiner, had a business based in School Lane, but died as a result of a tragic accident when Dan was only six. Thereafter Dan was brought up single handedly by his mother.After attending primary school in Carluke from 1920 to 1927, Dan entered the High School of Glasgow. It was during his third year there that he started studying calculus on his own. He became so enthused by the subject that he set his sights on a career teaching mathematics, at university if at all possible. On leaving school in 1932, he embarked on the M.A. honours course in Mathematics and Natural Philosophy at the University of Glasgow. At that time the Mathematics Department was under the leadership of Professor Thomas MacRobert; the honours course in Mathematics consisted mainly of geometry, calculus and analysis, and the combined honours M.A. with Natural Philosophy was the standard course for mathematicians. A highlight of his first session at university was attending a lecture on the origins of the general theory of relativity, given on 20th June 1933 by Albert Einstein. This was the first of a series of occasional lectures on the history of mathematics funded by the George A. Gibson Foundation which had been set up inmemory of the previous head of the Mathematics Department. From then on, relativity was to be one of Dan's great interests, lasting a lifetime; indeed, on holiday in Iona the year before he died, Dan's choice of holiday reading included three of Einstein's papers.
PBW THEOREMS AND FROBENIUS STRUCTURES FOR QUANTUM MATRICES
Authors: GAVARINI FABIO 
Published: November 2007

AbstractLet $G \in \{{\it Mat}_n(\C), {GL}_n(\C), {SL}_n(\C)\}$, let $\Oqg$ be the quantum function algebra – over $\Z [q,q^{-1}]$ – associated to G, and let $\Oeg$ be the specialisation of the latter at a root of unity ϵ, whose order ℓ is odd. There is a quantum Frobenius morphism that embeds $\Og,$ the function algebra of G, in $\Oeg$ as a central Hopf subalgebra, so that $\Oeg$ is a module over $\Og$. When $G = {SL}_n(\C)$, it is known by [3], [4] that (the complexification of) such a module is free, with rank ℓdim(G). In this note we prove a PBW-like theorem for $\Oqg$, and we show that – when G is Matn or GLn – it yields explicit bases of $\Oeg $ over $ \Og$ over $\Og,$. As a direct application, we prove that $\Oegl$ and $\Oem$ are free Frobenius extensions over $\Ogl$ and $\Om$, thus extending some results of [5].
SPATIALLY NONDECAYING SOLUTIONS OF THE 2D NAVIER-STOKES EQUATION IN A STRIP
Authors: ZELIK SERGEY 
Published: November 2007

AbstractThe weighted energy theory for Navier-Stokes equations in 2D strips is developed. Based on this theory, the existence of a solution in the uniformly local phase space (without any spatial decaying assumptions), its uniqueness and the existence of a global attractor are verified. In particular, this phase space contains the 2D Poiseuille flows.
VOLUME INEQUALITIES FOR Lp-JOHN ELLIPSOIDS AND THEIR DUALS
Authors: FENGHONG LU , GANGSONG LENG 
Published: November 2007

AbstractIn this paper, we establish some inequalities among the Lp-centroid body, the Lp-polar projection body, the Lp-John ellipsoid and its dual, which are the strengthened version of known results. We also prove inequalities among the polar of the Lp-centroid body, the Lp-polar projection body, the Lp-John ellipsoid and its dual.
BIHARMONIC LAGRANGIAN SURFACES OF CONSTANT MEAN CURVATURE IN COMPLEX SPACE FORMS
Authors: SASAHARA TORU 
Published: November 2007

AbstractBiharmonic Lagrangian surfaces of constant mean curvature in complex space forms are classified. A further important point is that new examples of marginally trapped biharmonic Lagrangian surfaces in an indefinite complex Euclidean plane are obtained. This fact suggests that Chen and Ishikawa's classification of marginally trapped biharmonic surfaces [6] is not complete.
Selection of promising genotypes based on path and cluster analyses
Authors: KOZAK M. , BOCIANOWSKI J. , RYBIŃSKI W. 
Published: November 2007

SUMMARYThe objective of the present paper was to propose a statistical approach to support selection of the most promising genotypes in a breeding programme. The approach is based on applying two state-of-the-art statistical methodologies, likelihood-based path analysis and model-based cluster analysis. The first method is applied to find a causal mechanism lying behind a biological process of development of final crop yield. These results are then used for weighting traits to be used in cluster analysis, which helps select genotypes possessing a desirable level of yield and yield-contributing traits. An application of the approach is presented for a 2-year study on 22 grasspea genotypes, two cultivars (Derek and Krab) and 20 mutants from those cultivars. Seed yield/plant and seven yield-related traits were studied. Among these, plant height, number of branches/plant, pod length and number of seeds/plant determined seed yield; number of pods/plant influenced seed yield only for 2002. These results were used for appropriate weighting in cluster analysis, which indicated that cultivar Krab and its two mutants, K3 and K64, had the best level of the traits and were the most stable genotypes.
The contribution of the gibberellin-insensitive semi-dwarfing (Rht) genes to genetic variation in wheat seedling growth in response to osmotic stress
Authors: LANDJEVA S. , KORZUN V. , STOIMENOVA E. , TRUBERG B. , GANEVA G. , BÖRNER A. 
Published: November 2007

SUMMARYThe effects of various gibberellin-insensitive semi-dwarfing (Rht) alleles and background genotypes on the growth response of wheat seedlings to simulated low water potential were investigated. Four sets of near-isogenic lines, each consisting of six members (Rht-B1a+Rht-D1a (rht), Rht-B1b, Rht-B1c, Rht-D1b, Rht-B1b+Rht-D1b and Rht-B1c+Rht-D1b), and one set of five members (rht, Rht-B1b, Rht-B1c, Rht-B1d and Rht-D1b) were germinated in the presence of polyethylene glycol (PEG). The growth responses were assessed by measuring the lengths of the longest root, coleoptile and longest leaf (shoot) and calculating the root length:shoot length ratio and a tolerance index (TI). Seedling growth was significantly affected by the allelic status at the Rht loci, background genes and the water potential. The PEG treatment had major effects on root and shoot growth. Coleoptile growth was mainly affected by the Rht alleles. There were significant interactions of the Rht allele and variety on the growth response to low water potential. Genotypes with longer roots, coleoptiles and shoots when grown in water, as determined by the Rht allelic status (rht, Rht-B1b and Rht-D1b) and varietal background, had the highest TI and maintained this advantage under stress, while genotypes with smaller seedlings (Rht-B1c and Rht-B1c+Rht-D1b) when grown in water were more strongly affected.