bluuebunny/crossref_metadata_2025_split huggingface dataset:
Über Thiazole, XVIII. Mitteil.): Über die Synthese von 2‐[d‐gluco‐Pentaoxy‐pentyl]‐thiazolen
Authors: Beyer Hans , Schultz Ulrich 
Published: May 2007

AbstractEs wird die Darstellung des 2‐[d‐gluco‐Pentaoxy‐pentyl]‐4‐phenyl‐thiazols beschrieben.Aus der Literatur sind zahlreiche Verbindungen bekannt, bei denen der Einbau einer Zuckerkette in heterocyclische Ringsysteme in der Weise erfolgte, daß ein, zwei oder auch drei Kohlenstoffatome des Zuckermoleküls dem Heterocyclus angehören. Wir verweisen in diesem Zusammenhang auf das kürzlich erschienene Referat „Heterocyclische Verbindungen aus Zuckern”︁ von H. Vogel1). Danach und nach unserer Kenntnis ist es bisher nicht gelungen, einfache Zucker in den Thiazolkern einzubauen. Lediglich in einem Fall war es durch Kondensation von einfachen Zuckern mit Cystein möglich, zu Zuckerabkömmlingen der Thiazolidin‐carbonsäure (4)2) zu kommen.Für die von uns geplanten Untersuchungen war die Arbeit von C. Neuberg und H. Wolff3) von Interesse, wonach bei der Einwirkung von Phenyl‐ bzw. Allyl‐senföl auf d‐Glucosamin in glatter Reaktion 1‐Phenyl (bzw. Allyl)‐2‐mercapto‐4‐[d‐arabo‐tetraoxy‐butyl]‐imidazol entsteht. Als Zwischenprodukt bildet sich hierbei N‐[Anilino‐thioformyl]‐[bzw. N‐(Allylamino‐thioformyl])‐d‐glucosamin, das anschließend unter Wasseraustritt in das Imidazolderivat übergeht. Demnach reagiert bei gleichzeitiger Anwesenheit einer Sulfhydryl‐ und einer sekundaren Aminogruppe bevorzugt die letztere. Würde sich die SH‐Gruppe an der Wasserabspaltung beteiligen, so müßte ein Thiazolylzucker entstehen, in dem die C‐Atome 1 und 2 des Glucosemoleküls dem Thiazolring angehören. Eine derartige Kondensation ließ sich bisher nicht realisieren. Ein weiteres Beispiel dafür, daß das lactolische Hydroxyl des Zuckers vornehmlich mit einer Aminogruppe reagiert, ist die Bildung des d‐Glucose‐thioharnstoffs4) aus der d‐Glucose und Thioharnstoff in Gegenwart von Salzsäure.
Über die Dien‐Synthese von Thiophenverbindungen mit Maleinsäure‐anhydrid (Mehrkernige Thiophene, II. Mitteil.)
Authors: Dann Otto , Kokorudz Michael , Gropper Robert 
Published: May 2007

Abstract4.5;6.7‐Dibenzo‐isothionaphthen und das aus 2.5‐Dimethyl‐thiophen und Acetonylaceton in Fluorwasserstoff hergestellte 1.3.4.7‐ Tetramethyl‐isothionaphthen addieren Maleinsäure‐anhydrid. Nach diesem Verhalten bei der Dien‐Synthese und bei der Ultraviolettabsorption kann man das Ringsystem des Isothionaphthens zwischen dem des Anthracens und dem des Naphthalins einordnen.
Über Chlormethylchlorsilane
Authors: Runge Franz , Zimmermann Wolfgang 
Published: May 2007

AbstractEs werden die Chlorderivate der drei möglichen Methyl‐chlorsilane dargestellt und beschrieben.Die Chlorierung läßt sich beim Methyl‐trichlor‐silan leicht bis zum Ersatz aller Wasserstoffatome treiben, ohne daß Zwischenstufen gefaßt werden konnten, beim Dimethyl‐dichlor‐silan bis zur Substitution von fünf Wasserstoffatomen. Beim Trimethyl‐chlorsilan können maximal acht Wasserstoffatome ersetzt werden.Das Sublimationsvermögen dieser Verbindungen ist an die Anwesenheit einer Trichlormethylgruppe im Molekül gebunden.
Die Alkaloide der Haemanthus‐Hybride „König Albert”︁ (IV. Mitteil. über Amaryllidaceen‐Alkaloide
Authors: Boit Hans‐G. 
Published: May 2007

AbstractAus der Haemanthus‐Hybride „König Albert”︁ werden Lycorin und zwei bisher nicht beschriebene Alkaloide Haemanthidin, C17H19O5N, und Haemanthamin, C17H19O4N isoliert.
Über die Substitution von Tosyloxy‐Gruppen durch Acetoxy‐Gruppen in Polyoxy‐Verbindungen. Eine neue Darstellungsweise von l‐Idose‐Derivaten aus d‐Glucose
Authors: Vargha L. 
Published: May 2007

AbstractEs wurde der Austausch von Tosyloxy‐Gruppen gegen Acetoxy‐Gruppen in einigen Zucker‐Derivaten untersucht. Tosylester, welche die Tosyloxy‐Gruppe an einem Ring‐Kohlenstoffatom tragen, erwiesen sich unter den angewandten Reaktionsbedingungen als sehr beständig. Dagegen ließen sich die Tosyloxy‐Gruppen durch Acetoxy‐Gruppen in solchen Verbindungen ersetzen, in denen sie sich in der Seitenkette eines Furanose‐Ringes befinden.Es wurde so ein neuer, ergiebiger präparativer Weg von der d‐Glucose zur l‐Idose gefunden. Die l‐Idose konnte nicht in kristallinem Zustand gewonnen werden; sie wandelte sich beim Aufbewahren allmählich in l‐Sorbose um.
Darstellung und Verhalten von Bicyclo‐[1.2.3]‐octen und Bicyclo‐[2.2.3]‐nonen Beiträge zur Kenntnis der Wagnerschen Umlagerung und der Phenylazid‐Reaktion
Authors: Alder Kurt , Krieger Hans , Weiβ Herbert 
Published: May 2007

AbstractDurch vereinfachte Darstellungsmethoden werden das Bicyclo‐[1.2.3]‐octen‐(2) und das Bicyclo‐[1.2.3]‐octanol‐(2) zu leicht zugänglichen Verbindungen. Die Verfahren sind auch geeignet, die Reihe des Bicyclo‐[2.2.3]‐nonans zu erschließen. Bei der Hydratisierung nach Bertram‐Walbaum erleidet das Bicyclo‐[1.2.3]‐octen‐(2) eine Wagnersche Umlagerung und liefert das Bicyclo‐[2.2.2]‐octanol‐(2).Sowohl das Bicyclo‐[1.2.3]‐octen‐(2) als auch das Bicyclo‐[2.2.3]‐nonen‐(2) zeigen bei der Phenylazid‐Reaktion nicht das Verhalten von Bicyclo‐[1.2.2]‐hepten‐Derivaten, sondern gleichen einfachen monocyclischen Olefinen.
Alkaloide von Sprekelia formosissima, Galanthus Elwesii, Zephyranthes candida und Crinum Powellii (VIII. Mitteil. über Amaryllidaceen‐Alkaloide1))
Authors: Boit Hans‐G. , Ehmke Horst 
Published: May 2007

AbstractEs werden die folgenden Alkaloide isoliert: Aus Sprekelia formosissima Tazettin, Haemanthamin, Lycorin und Haemanthidin; aus Galanthus Elwesii Galanthamin, Lycorin, Tazettin und Haemanthamin; aus Zephyranthes candida Lycorin, Nerinin, Tazettin und Haemanthamin; aus Crinum Powellii Lycorin, Crinidin, Crinin, Crinamin und das bisher nicht beschriebene Powellin.
Synthesis of homogeneous anisotropic turbulent fields with prescribed second‐order statistics by the random spots method
Authors: Kornev Nikolai , Kröger Hannes , Hassel Egon 
Published: May 2007

AbstractThe problem of synthesis of homogeneous anisotropic turbulent fields with prescribed autocorrelation functions is solved using the method of random spots method (Commun. Numer. Meth. Engng 2007; 23:35–43). Every spot has an inner distribution f of a velocity component. The resulting velocity field is found as a sum of contributions from all spots. The inner distribution f is found from the condition that the resulting field has the prescribed statistical properties. The paper presents analytical solutions for f in the case of homogeneous turbulent fields. A numerical solution for the inhomogeneous case is discussed in (Commun. Numer. Meth. Engng 2007; 23:35–43). Copyright © 2007 John Wiley & Sons, Ltd.
APEX‐Map: a parameterized scalable memory access probe for high‐performance computing systems
Authors: Strohmaier Erich , Shan Hongzhang 
Published: May 2007

AbstractThe memory wall between the peak performance of microprocessors and their memory performance has become the prominent performance bottleneck for many scientific application codes. New benchmarks measuring data access speeds locally and globally in a variety of different ways are needed to explore the ever increasing diversity of architectures for high‐performance computing. In this paper, we introduce a novel benchmark, APEX‐Map, which focuses on global data movement and measures how fast global data can be fed into computational units. APEX‐Map is a parameterized, synthetic performance probe and integrates concepts for temporal and spatial locality into its design. Our first parallel implementation in MPI and various results obtained with it are discussed in detail. By measuring the APEX‐Map performance with parameter sweeps for a whole range of temporal and spatial localities performance surfaces can be generated. These surfaces are ideally suited to study the characteristics of the computational platforms and are useful for performance comparison. Results on a global‐memory vector platform and distributed‐memory superscalar platforms clearly reflect the design differences between these different architectures. Published in 2007 by John Wiley & Sons, Ltd.
Multi‐installment divisible load processing in heterogeneous distributed systems
Authors: Drozdowski M. , Lawenda M. 
Published: May 2007

AbstractDivisible loads are parallel applications with fine granularity and negligible data dependencies. Such computations can be divided into parts of arbitrary sizes and processed independently in parallel. The load distribution process incurs considerable communication delays. To reduce processor waiting time during the computation initialization phase, the load is distributed in multiple small installments rather than in one big chunk. In this paper we analyze multi‐installment divisible load processing in heterogeneous distributed systems. Scheduling divisible loads in heterogeneous systems is hard because the sizes of the installments should be adjusted to the communication and computation capabilities of the system. We show that ignoring heterogeneity of the distributed system may result in arbitrarily bad solutions. Two algorithms are proposed to gear the load chunk sizes to different communication and computation speeds: an optimization branch‐and‐bound algorithm and a heuristic based on a genetic search method. The running times of both methods and the quality of the solutions are compared. Then, we use these algorithms to study the features of the multi‐installment divisible load scheduling problem. We demonstrate that it has both combinatorial and algebraic nature, and that optimum solutions are harder to find with the growing heterogeneity of the system. Copyright © 2007 John Wiley & Sons, Ltd.
Organic Electronic Devices and Their Functional Interfaces
Authors: Koch Norbert 
Published: May 2007

AbstractA most appealing feature of the development of (opto)electronic devices based on conjugated organic materials is the highly visible link between fundamental research and technological advances. Improved understanding of organic material properties can often instantly be implemented in novel device architectures, which results in rapid progress in the performance and functionality of devices. An essential ingredient for this success is the strong interdisciplinary nature of the field of organic electronics, which brings together experts in chemistry, physics, and engineering, thus softening or even removing traditional boundaries between the disciplines. Naturally, a thorough comprehension of all properties of organic insulators, semiconductors, and conductors is the goal of current efforts. Furthermore, interfaces between dissimilar materials—organic/organic and organic/inorganic—are inherent in organic electronic devices. It has been recognized that these interfaces are a key for device function and efficiency, and detailed investigations of interface physics and chemistry are at the focus of research. Ultimately, a comprehensive understanding of phenomena at interfaces with organic materials will improve the rational design of highly functional organic electronic devices.
Synthesis, spectroscopic and anti‐tumor studies of polyphenol‐linoleates derived from natural polyphenols
Authors: Mustafa Jamal , Khan Shabana I. , Ferreira Daneel , Khan Ikhlas A. 
Published: May 2007

AbstractAn efficient first synthesis of di‐, hexa‐ and octa‐esters (octadeca‐Z‐9,12‐dienoates, linoleates) from natural 1,5‐bis‐(4'‐hydroxyphenyl)penta‐Z‐1,4‐diene (Ginkgo biloba L.), (–)‐epigallocatechin and (–)‐epigallocatechin‐3‐O‐gallate (jasmine tea/green tea), respectively, was developed. Using dicyclohexyl carbodiimide as an activating reagent in the presence of a catalytic amount of 4‐dimethylaminopyridine in polyesterification reactions gave di‐, hexa‐ and octa‐products (4), (7), and (8), respectively, in quantitative yields. A three‐step efficient procedure for the synthesis of 1,5‐bis‐[4'‐O‐(octadec‐Z‐9”,12”‐dienoate)phenyl]penta‐Z‐1,4‐diene (4) was also developed. The key step in the synthesis involved a stereo selective Wittig diolefination reaction that produced the penta‐Z‐1,4‐diene system of (4). 1H and 13C NMR and MS techniques confirmed the structures of the esters. The esterified compounds were tested for in vitro anti‐tumor activities against four and three human cancer cell lines at NCNPR and at NCI, respectively. They were found inactive as they failed to inhibit 50% growth of these cancer cells.
Analytical methods for determination of trans fatty acid content in food
Authors: Juanéda Pierre , Ledoux Martial , Sébédio Jean‐Louis 
Published: May 2007

AbstractAdequate analytical tools are required for labelling food products for trans fatty acid (TFA) contents. The choice of the fatty acid (FA) derivatisation is a crucial step in obtaining good results, in particular with short‐chain and conjugated FA. Several gas chromatographic and infrared spectrophometric methods have been developed for analysing TFA in foods, some of which have been validated as official methods after collaborative studies. Complete analysis of total FA often requires the use of complementary high‐performance liquid chromatography methods. This paper reviews the analytical methods developed for identifying and quantifying TFA in foods and presents the official methods of analysis. Neither of these analytical methods enables a TFA naturally occurring in basic food to be distinguished from a TFA formed during an industrial process.
Domino [2+2]/[2+1] and [3+2]/[2+1] Reaction Sequences of Alkynyl(alkoxy) Chromium Fischer Carbene Complexes
Authors: Pérez‐Anes Alexandra , García‐García Patricia , Suárez‐Sobrino Ángel Luis , Aguilar Enrique 
Published: May 2007

AbstractA tandem [2+2]/[2+1] sequence takes place between alkynyl(alkoxy) Fischer carbene complexes and 2,3‐dihydrofuran, producing three‐component adducts diastereoselectively in moderate yields. On the other hand, a [3+2]/[2+1] (1,3‐dipolar cycloaddition/cyclopropanation) sequence takes place between an alkynyl(alkoxy) Fischer carbene complex, trimethylsilyldiazomethane, and methyl acrylate or 2,3‐dihydrofuran. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
On the application of CZE to the study of protein denaturation
Authors: Piaggio Maria V. , Peirotti Marta B. , Deiber Julio A. 
Published: May 2007

AbstractExperimental mobilities obtained from CZE are used to study protein denaturation through a model based on known physicochemical theories. This model is able to provide additional information concerning the folded and unfolded protein states from mobility data. Its use comprises first the evaluation of relevant parameters of the protein microstates like the electrostatic free energy, apart from the classical conformational free energy, and second the expression of raw experimental data concerning the folding–unfolding transition into more specific physicochemical parameters like protein hydrodynamic radius, net charge number, and hydration. Spurious effects that are intrinsic to the experimental evaluation of the mobility of protein states, like BGE viscosity, pH, and ionic strength variations accompanying the changes of the denaturant agent intensity are eliminated. In order to illustrate the proposal of this work, two case studies are considered here. The first one concerns thermal and urea denaturations of horse heart ferricytochrome c and the second one involves thermal denaturation of hen egg‐white lysozyme. Thus, relevant theoretical thermodynamic considerations of the folded–unfolded protein transition are presented, where the electrostatic free energy is included explicitly in the effective free energy. It is found that this transition involves sharp increases of hydrodynamic radius and protein hydration.
Microvariability in the early stages of cobble weathering by microenvironment on a glacier foreland, Storbreen, Jotunheimen, Norway
Authors: Thorn Colin E. , Darmody Robert G. , Campbell Sean W. , Allen Charles E. , Dixon John C. 
Published: May 2007

AbstractThe initial stages of cobble weathering, measured as increasing percentage porosity, were calculated for sets of cobbles taken from the foreland of Storbreen, a cirque glacier in the Jotunheimen, Norway. Cobbles were taken from in front of the 1998 glacier snout, from the 1928, 1870, 1810 and 1750 moraine crests and from the ∼10 000‐year‐old land surface beyond the Neoglacial foreland limit. Three microenvironments were examined within each site: (1) lichen‐free surfaces from exposed cobbles, (2) lichen‐covered surfaces from exposed cobbles and (3) buried cobbles taken from a soil depth of ∼40 cm. Percentage porosity within plagioclase minerals was calculated using backscatter electron images of prepared thin sections. Porosity was calculated from five depth profiles into each cobble. Depth profiles were subdivided into a sequence of 50 µm × 50 µm rectangles running to at least a nominal depth of 500 µm within each cobble. Three cobbles from each dated land surface were sampled, except for the 1750 surface, which had five cobbles. Statistical analysis was by analysis of variance of rank‐order transformed data. Findings indicate that cobbles close to the glacier snout are largely unweathered; also, weathering is generally weak in the 1928, 1870 and 1810 positions, but statistically significantly higher in the 1750‐ and 10 000‐year‐old positions. Weathering of buried cobbles always exceeded weathering of exposed cobbles and may possibly reach a value beyond which it cannot progress while retaining surface cohesion. The degree of weathering on lichen‐free and lichen‐covered cobble surfaces is not initially distinguishable, but diverges sharply after ∼250 years, when lichen‐covered surfaces experience significantly higher totals. Overall, the weathering trend in cobbles matches that found in soils at the same sites. Copyright © 2007 John Wiley & Sons, Ltd.
Darwinian origin of landforms
Authors: Corenblit Dov , Steiger Johannes , Gurnell Angela , Tabacchi Eric 
Published: May 2007

AbstractWhilst earth surface landforms evolve largely as a result of the activity of certain living organisms, the biologically driven geomorphic changes have evolutionary consequences on organisms and ecological communities. Recognition of complex biotic–abiotic feedbacks may lead to deep changes in our understanding of geomorphology. Copyright © 2007 John Wiley & Sons, Ltd.
The pricing of foreign currency options under jump‐diffusion processes
Authors: Ahn Chang Mo , Cho D. Chinhyung , Park Keehwan 
Published: May 2007

AbstractIn this article, the authors derive explicit formulas for European foreign exchange (FX) call and put option values when the exchange rate dynamics are governed by jump‐diffusion processes. The authors use a simple general equilibrium international asset pricing model with continuous trading and frictionless international capital markets. The domestic and foreign price level are introduced as state variables that contain jumps caused by monetary shocks and catastrophic events such as 9/11 or Hurricane Katrina. The domestic and foreign interest rates are stochastic and endogenously determined in the model and are shown to be critically affected by the jump risk of the foreign exchange. The model shows that the behavior of FX options is affected through the impact of state variables and parameters on the nominal interest rates. The model contrasts with those of M. Garman and S. Kohlhagen (1983) and O. Grabbe (1983), whose models have exogenously determined interest rates. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:669–695, 2007
Using relative distributions to investigate the body mass index in England and Canada
Authors: Contoyannis Paul , Wildman John 
Published: May 2007

AbstractIn this paper we use relative distributions to examine changes in the distribution of the body mass index (BMI) in England and Canada during the period 1994/5–2000/1. The use of relative distributions allows us to describe changes in the whole distribution of the BMI in a non‐parametric fashion. While statistics analogous to the Gini index can be constructed based on the relative distribution, important characteristics of changes in the distribution of the BMI such as changes in the proportions overweight and obese are more naturally handled using measures of relative polarization. Our results show that while BMI has increased in both countries, BMI in England has increased at a much faster rate than in Canada. Both groups show polarization over time towards both tails of the weight distribution, with the English polarizing towards the upper tail at a faster rate than Canadians. Copyright © 2007 John Wiley & Sons, Ltd.
Resveratrol and trimethylated resveratrol protect from acute liver damage induced by CCl4 in the rat
Authors: Rivera Horacio , Shibayama Mineko , Tsutsumi Victor , Perez‐Alvarez Victor , Muriel Pablo 
Published: May 2007

AbstractThe importance of hydroxyl groups in the antioxidant and hepatoprotective properties of resveratrol was investigated. To achieve this, resveratrol or its trimethylated analog were administered (10 mg kg−1, p.o.) to male Wistar rats and liver damage was induced by acute administration of CCl4 (4 g kg−1, p.o.); appropriate controls were performed. The animals were killed 24 h after CCl4 intoxication. The amount of reduced glutathione (GSH) in the liver was not modified by any treatment; interestingly, the GSH/GSSG (oxidized glutathione) ratio decreased in the groups receiving CCl4 and resveratrol associated with an increase in GSSG. In blood GSH and the GSH/GSSG ratio were decreased by CCl4; both effects were completely prevented by any of the compounds tested. Lipid peroxidation and the activity of γ‐glutamyl transpeptidase were increased significantly after CCl4. Resveratrol partially prevented these increases and surprisingly, trimethylated resveratrol completely prevented the increase of these markers. Both compounds partially but significantly prevented the increase in the activity of alanine aminotransferase; this result agrees with observations in the histological analysis. Both tested compounds administered alone produced no effect. The results of the present study suggest that OH groups are important for the antioxidant and hepatoprotective properties of the molecule of resveratrol; nevertheless, these effects can be improved by replacing hydrogen by a methyl in these groups. The differences in the antioxidant and hepatoprotective effects of these compounds could be due to the possibility that the trimethylated resveratrol acts like a prodrug, prolonging, probably, the half‐life of the original compound. Copyright © 2007 John Wiley & Sons, Ltd.