bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular and crystal structure of Ac-(Z)-ΔAbu-NMe2 and Ac-DL-Abu-NMe2 as compared to those of related molecules
Authors: Siodłak Dawid , Broda Malgorzata A. , Rzeszotarska Barbara , Kołodziejczyk Edyta , Kozioł Anna E. 
Published: April 2004

Abstract
The molecular and crystal structures of two homologous amino acid derivatives: N-acetyl-α,β-dehydro-butyrine N´,N´-dimethylamide (1) and N-acetyl-DL-butyrine N´,N´-dimethylamide (2), have been determined by X-ray crystallography. Similar solid-state association of both compounds is observed; despite different molecular conformation, they form centrosymmetric dimers linked by the intermolecular N–H…O hydrogen bonds. The conformation of two crystallographically independent molecules of 1 [with torsion angles ϕ, ψ, χ
1 ≈ (–47°, 130°, 3°), respectively] is also characteristic of other related diamides – ΔAla, ΔPhe and ΔLeu – previously studied in the solid state. To analyse whether this conformation is rigid for the free molecule of 1, its fully relaxed (ϕ, ψ) conformational energy map was generated with the ab initio methods. The conformer with the torsion angles ϕ,ψ = –43°, 130°, being very close to the solid-state conformers of usaturated amides, has been found among the energy-minimised structures of this molecule.
Synthesis and Characterisation of ν3‐Octahedral [Ni36Pd8(CO)48]6− and [Ni35Pt9(CO)48]6− Clusters Displaying Unexpected Surface Segregation of Pt Atoms and Molecular and/or Crystal Substitutional Ni/Pd and Ni/Pt Disorder
Authors: Femoni Cristina , Iapalucci Maria Carmela , Longoni Giuliano , Svensson Per H. , Zanello Piero , Fabrizi de Biani Fabrizia 
Published: April 2004

AbstractThe synthesis and structure, as well as the chemical and electrochemical characterisation of two new ν3‐octahedral bimetallic clusters with the general [Ni44−xMx(CO)48]6− (M = Pd, x = 8; M = Pt, x = 9) formula is reported. The [Ni35Pt9(CO)48]6− cluster was obtained in reasonable yields (56 % based on Pt) by reaction of [Ni6(CO)12]2− with 1.1 equivalents of PtII complexes, in ethyl acetate or THF as the solvent. The [Ni36Pd8(CO)48]6− cluster was obtained from the related reaction with PdII salts in THF, and was isolated only in low yields (5–10 % based on Pd), mainly because of insufficient differential solubility of its salts. The unit cell of the [NBu4]6[Ni35Pt9(CO)48] salt contains a substitutionally Ni–Pt disordered [Ni24(Ni14−xPtx)Pt6(CO)48]6− (x = 3) hexaanion. A combination of crystal and molecular disorder is necessary to explain the disordering observed for the Ni/Pt sites. The unit cell of the corresponding [Ni36Pd8(CO)48]6− salt contains two independent [Ni30(Ni8−xPdx)Pd6(CO)48]6− (x = 2) hexaanions. The two display similar substitutional Ni–Pd disorder, which probably arises only from crystal disorder. The structure of [Ni36Pd8(CO)48]6− establishes the first similarity between the chemistry of Ni‐Pd and Ni‐Pt carbonyl clusters. A comparison of the chemical and electrochemical properties of [Ni35Pt9(CO)48]6− with those of the related [Ni38Pt6(CO)48]6− cluster shows that surface colouring of the latter with Pt atoms decreases redox as well as protonation propensity of the cluster. In contrast, substitution of all internal Pt and two surface Ni with Pd atoms preserves the protonation behaviour and is only detrimental with respect to its redox aptitude. A qualitative rationalisation of the different surface‐site selectivity of Pt and Pd, based on distinctive interplays of MM and MCO bond energies, is suggested.
Synthesis and Redox Behavior of Ruthenocene‐Terminated Oligoenes: Characteristic and Stable Two‐Electron Redox System and Lower Potential Shift of the Two‐Electron Oxidation Wave with Elongating Conjugation
Authors: Sato Masaru , Nagata Toru , Tanemura Atsushi , Fujihara Takashi , Kumakura Shigekazu , Unoura Kei 
Published: April 2004

AbstractRuthenocene‐terminated butadienes and hexatrienes were prepared by the Wittig reaction of 3‐ruthenocenyl‐2‐propenals with ruthenocenylmethylphosphonium salts and the Mukaiyama coupling of the propenals, respectively. Cyclic voltammetry of these complexes indicated that they were involved in a stable two‐electron redox process. The oxidation potentials for ruthenocene‐terminated oligoenes shifted progressively to lower potential with the increasing CHCH units as follows: RcRc (0.32 V)>RcCHCHRc (+0.09 V)>Rc(CHCH)2Rc (−0.06 V)>Rc(CHCH)3Rc (−0.07 V), (Rc=ruthenocene). The tendency is in remarkable contrast to that in the successive one‐electron redox process. These complexes were chemically oxidized to give stable crystalline solids, whose structures were confirmed by NMR spectroscopy and X‐ray analysis to be oligoene analogues of a bis(fulvene) complex, for example, [(η5‐C5Me5)Ru{μ2‐η6:η6‐C5H4CH(CHCH)nCHC5H4}Ru(η5‐C5Me5)]2+ (n=1 or 2). The DFT calculation of the two‐electron‐oxidized species reproduced well the fulvene‐complex structure for the ruthenocene moieties. Since both the neutral and oxidized species are stable and chemically reversible, this redox system may be serviceable as a two‐electron version of the ferrocene one‐electron redox system.
Catalytic Activity of Crown‐Ethers in Oxidation Reactions of Benzyl Alcohol with Potassium Chlorochromate.
Authors: Chuprin G. N. , Grigorash R. Ya. , Zlotsky S. S. , Kotlyar S. A. , Kamalov G. L. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
A Novel and Facile Synthesis of Dienals and Substituted 2H‐Pyrans via the Vilsmeier Reaction of α‐Oxo‐ketenedithioacetals.
Authors: Liu Yingchun , Dong Dewen , Liu Qun , Qi Yimei , Wang Zuo 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Acid‐Mediated Cyclization of 3‐Benzoyl‐2‐cyanobutyronitrile to 2‐Amino‐4‐methyl‐5‐phenylfuran‐3‐carbonitrile.
Authors: Watanuki Susumu , Sakamoto Shuichi , Harada Hironori , Kikuchi Kazumi , Kuramochi Takahiro , Kawaguchi Ken‐ichi , Okazaki Toshio , Tsukamoto Shin‐ichi 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of 5‐Arylamino‐5‐tert‐butyl‐5‐hydroxy‐2(5H)‐furanones
Authors: Kozminykh V. O. , Bukanova E. V. , Belyaev A. O. , Kozminykh E. N. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Novel Heterocyclic Troponoids: Synthesis of Pyridoimidazotropolones and Related Compounds by the Reaction of 5‐Nitrosotropolone with Several Azines.
Authors: Sato Ohki , Tsurumaki Kouichiro , Tamaru Syunnichi , Tsunetsugu Josuke 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
The Reaction Between tert‐Butyl Isocyanide and Acetylenic Esters in the Presence of 2‐Thenoyltrifluoroacetone: A Synthesis of Highly Functionalized 4H‐Pyrans.
Authors: Baharfar Robabeh , Hosseini Javad 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Generation of 5,6‐Dimethylene‐2(1H)‐pyridinones from [3,4‐b]Sulfolene Pyridinones and Application in Diels—Alder Reactions.
Authors: Govaerts Tom C. , Vogels Ilse A. , Compernolle Frans , Hoornaert Georges J. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
A Novel One‐Pot Synthesis of Derivatives of Aryldioxins and Aryldithiins.
Authors: Preedasuriyachai Patcharee , Charoonniyomporn Porntip , Karoonnirun Osit , Thongpanchang Tienthong , Thebtaranonth Yodhathai 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
A comparison of Ktrans measurements obtained with conventional and first pass pharmacokinetic models in human gliomas
Authors: Haroon Hamied A. , Buckley David L. , Patankar Tufail A. , Dow Graham R. , Rutherford Scott A. , Balériaux Danielle , Jackson Alan 
Published: April 2004

AbstractPurposeTo compare in a group of patients with cerebral gliomas the estimates of Ktrans between a conventionally established pharmacokinetic model and a recently developed first pass method.Materials and MethodsGlioma patients (23) were studied using T1‐weighted dynamic contrast‐enhanced magnetic resonance imaging (MRI), and two alternative pharmacokinetic models were used for analysis to derive the volume transfer constant Ktrans. These were a modified version of the established model (yielding KTK) and a recently published method based on first pass leakage profile (FP) of contrast bolus (yielding Kfp).ResultsWe found a strong correlation between intra‐tumoral median KTK and Kfp (rho = 0.650, P < 0.01), but the values from the conventional model were consistently and significantly higher (mean of inter‐tumoral Kfp and KTK medians were 0.018 minute−1 and 0.284 minute−1, respectively, P < 0.001). The spatial distribution of KTK and Kfp showed poor correlation in the presence of large vascular structures and good correlation elsewhere.ConclusionKTK and Kfp produce similar biologic information within voxels not dominated by vascular tissue. The FP method avoids erroneous overestimation of Ktrans in areas of significant intravascular contrast. Findings are in keeping with the predictions of previous mathematical simulations. J. Magn. Reson. Imaging 2004;19:527–536. © 2004 Wiley‐Liss, Inc.
Time‐domain combined field integral equation using Laguerre polynomials as temporal basis functions
Authors: Jung Baek Ho , Sarkar Tapan Kumar , Chung Young‐seek , Salazar‐Palma Magdalena , Ji Zhong 
Published: April 2004

AbstractIn this paper, we propose a novel formulation to solve the time‐domain combined field integral equation (TD‐CFIE) for analysing the transient electromagnetic response from three‐dimensional (3D) closed conducting bodies. Instead of the conventional marching‐on in time (MOT) technique, the solution methods in this paper are based on the Galerkin's method that involves separate spatial and temporal testing procedure. Triangular patch basis functions are used for spatial expansion and testing functions for arbitrarily shaped 3D closed structures. The time‐domain unknown coefficient is approximated as an orthonormal basis function set that is derived from the Laguerre functions. These basis functions are also used as the temporal testing. With the representation of the derivative of the transient coefficient in an analytic form, the time derivative terms in the integral equations can be handled analytically. We also propose an alternative formulation to solve the TD‐CFIE. Two methods are presented that results in very accurate and stable transient responses from conducting objects. Numerical results are presented and compared with the inverse discrete Fourier transform (IDFT) of frequency‐domain combined field integral equation (FD‐CFIE) solutions. Copyright © 2004 John Wiley & Sons, Ltd.
Uniaxial approach to time‐domain computations using electromagnetic potentials
Authors: K. Nikolova Natalia 
Published: April 2004

AbstractA new approach to transient electromagnetic (EM) analysis in terms of wave potentials is presented. It is based on the EM field and source scalarization in a non‐uniform medium. The algorithm computes two scalar wave functions of space‐time, which constitute a complete 3‐D solution. They represent the time‐dependent values of two collinear (electric and magnetic) vector potentials of known fixed direction throughout the computational volume. Auxiliary source functions are also computed but only at the location of material non‐uniformities. A finite‐difference implementation in the case of metallic boundaries and inclusions is considered. The algorithm offers approximately 30% reduction of the computation time and memory requirements in comparison with the FDTD method based on the Maxwell curl equations. The technique is illustrated with a number of waveguide examples. Copyright © 2004 John Wiley & Sons, Ltd.
Acylation of Cellulose with N,N′‐Carbonyldiimidazole‐Activated Acids in the Novel Solvent Dimethyl Sulfoxide/Tetrabutylammonium Fluoride
Authors: Hussain Muhammad Ajaz , Liebert Tim , Heinze Thomas 
Published: April 2004

AbstractSummary: Carboxylic acids were efficiently activated with N,N′‐carbonyldiimidazole (CDI) and applied for the acylation of cellulose under homogeneous conditions using dimethyl sulfoxide (DMSO)/tetrabutylammonium fluoride trihydrate (TBAF) as solvent. The simple and elegant method is a very mild and easily applicable tool for the synthesis of pure aliphatic, alicyclic, bulky, and unsaturated cellulose esters with degrees of substitution of up to 1.9. Products are soluble in organic solvents, e.g., DMSO or N,N‐dimethylformamide (DMF). The cellulose esters were characterized by elemental analysis, FT‐IR, 1H and 13C NMR spectroscopy and show no impurities or substructures resulting from side reactions.The esterification of cellulose using carboxylic acids activated in situ with N,N′‐carbonyldiimidazole.imageThe esterification of cellulose using carboxylic acids activated in situ with N,N′‐carbonyldiimidazole.
2. The raw materials of CA 2.1 Wood as natural raw materials for cellulose acetate production
Authors: Saka Shiro 
Published: April 2004

AbstractThe molecular arrangement of wood cell wall is described in relation to the physical and mechanical properties of wood. The chemical composition of wood is also summarized to illustrate the heterogeneity in distribution of cell wall constituents to use wood plup fibers judiciously as natural raw materials for cellulose acetate production.
Multiphase flow in deforming porous material
Authors: Schrefler B. A. 
Published: April 2004

AbstractA model for mechanical behaviour of saturated–unsaturated porous media is presented within the framework of thermodynamics of irreversible processes. It includes interfaces with thermodynamic properties between the constituents. The necessary balance equations are derived using averaging theories. Restrictions on the form of the constitutive equations are obtained by exploiting the entropy inequality according to the Coleman–Noll procedure. A particular form of the governing equations is then solved numerically. The validation of the model proposed through a comparison between experimental and numerical results and an application example concerning a tunnel fire conclude the paper. Copyright © 2004 John Wiley & Sons, Ltd.
Mixed‐enhanced formulation for finite deformation axisymmetric‐torsion
Authors: Kasper E. P. , Taylor R. L. 
Published: April 2004

AbstractThe development and implementation of a four‐noded quadrilateral element for the analysis of the axisymmetric‐torsion problem is presented in the context of the mixed‐enhanced method. The deformation gradient is developed from two sets of element interpolants, of which one may be explicitly obtained resulting in only two undetermined enhanced parameters needed for the satisfaction of the near incompressible limit. The resulting element arrays yield proper rank with standard 2×2 quadrature. The introduction of a three‐field variation statement for the problem along with the interpolations for the stress and deformation gradient render a variational stress recovery permissible. Several numerical examples are explored in the setting of finite kinematics with physically non‐linear material properties to further induce coupling between the radial and axial displacement and the longitudinal rotation. Copyright © 2004 John Wiley & Sons, Ltd.
Computational mechanics applied to interaction problems
Authors: Valliappan S. 
Published: April 2004

AbstractThis paper presents a general discussion on the application of computational mechanics concepts to solve engineering problems involving interaction effects between different media—for example, structure–soil/rock interaction and/or different phases such as solid–fluid interaction. The discussion includes illustrations based on numerical analyses of such problems using coupled finite element and boundary element, coupled finite element and infinite element methods. A few of the other mechanics concepts such as damage mechanics and optimization are also included in the discussion. Copyright © 2004 John Wiley & Sons, Ltd.
Review: The adsorption of functional polymers from their organic solutions: applications to fuel additives
Authors: Chevalier Yves , Fixari Bernard , Brunel Sylvain , Marie Emmanuelle , De Guio Philippe 
Published: April 2004

AbstractFunctional polymers are used as additives in the formulation of fuels either for their detergency properties or for retaining cold weather operability. Examples of recent research work aimed at a better understanding of the physico‐chemical phenomena involved and at the design and synthesis of new polymers are described. One phenomenon common in most applications is the adsorption of the polymers on various surfaces (gums, soot, metal walls, paraffin crystals). In the case of chain‐end functional polymers, strong affinity of the functional groups for the surface sites is required in order to reach the high adsorption densities that allow optimum stabilization properties. This can be achieved by a correct choice of the functional group (of its polymeric nature, having a primary amino group that will strongly interact with surface sites) or by the design of the macromolecular architecture. In the case of very complex systems (eg the crystallization of paraffins in diesel fuel), the selection of relevant experimental models allows investigations into mechanisms at a microscopic level. Such studies would obviously not be possible on the diesel fuel itself, which is nevertheless the only really representative sample. Copyright © 2004 Society of Chemical Industry
Pyrazines on Solid Support from Peptides by Periodinane Oxidation of Threonine Side‐Chains. A Quantitative Chemical Transformation (QCT) for Combinatorial Chemistry
Authors: Christensen Caspar , Tornøe Christian W. , Meldal Morten 
Published: April 2004

AbstractThe β‐hydroxymethylene in threonine residues adjacent to an N‐terminal amino acid were subjected to oxidation effected by Dess‐Martin periodinane on solid support. Fmoc‐cleavage at the N‐terminal amino acid afforded 3,6‐dihydro‐1H‐pyrazin‐2‐one, which oxidized spontaneously to the 1H‐pyrazin‐2‐ones (3a–v). A variety of naturally occurring and synthetic α‐amino acids gave rise to a diverse subset of functionalized 1H‐pyrazin‐2‐ones. An amino functionality in the side‐chain of the N‐terminal amino acid residue allowed elongation by conventional solid phase peptide chemistry (5a–b). Furthermore, elongation of the side‐chain with Thr and a second amino acid followed by oxidation resulted in bis 1H‐pyrazin‐2‐ones in high yield (8).
Severe obsessive compulsive disorder in adolescence: a report of eight cases
Authors: Apter A. , Bernhout E. , Tyano S. 
Published: April 2004

AbstractThe treatment and clinical features of eight adolescents with obsessive compulsive disorder severe enough to warrant hospitalization are described. Attempts to use behaviour therapy failed, due to lack of co‐operation from the patients. Nevertheless, response to non‐specific psychotherapy and milieu therapy was surprisingly good. These observations are somewhat different from those reported in previous literature. The reasons for this difference are discussed.
Proper Conduct (Adab) is Everything: TheFutuwwat-nāmah-i Sulṭānīof Husayn Vaᶜiz-i Kashifi
Authors: Loewen Arley 
Published: April 2004

Iranian Society has Traditionally had a Deep Admiration for the Courageous hero or champion, often calledjawānmard(lit., young man;jawānmardī—manliness). Such a person possessed the aggregate of all positive virtues of manhood—courage, honesty, hospitality and generosity. One model of thejawānmardis the heroic warrior, as reflected in Persian epic literature and classical popular romance. In Persian culture, Rustam, the legendary pre-Islamic hero of the epicShah-nāmahembodied the characteristics of the heroic warrior.A related term forjawānmardis the Arabicfatā(lit., young man; manliness—futuwwa; Persianfutuwwat), which designated the ideal hero of pre-Islamic Arabia. In Perso-Islamic culture, a synthesis of ancient Persian and Arabo-Islamic ideals, the ethic of piety towards God, which was influenced by the increasing dominance of Sufism, shaped a second model of heroism.
Alcoholic macrocytosis–is there a role for acetaldehyde and adducts?
Authors: Niemelä Onni , Parkkila Seppo 
Published: April 2004

AbstractAlthough alcohol abuse is known to cause a wide array of adverse effects on blood cell formation, the molecular mechanisms by which alcohol exerts its toxic actions have remained poorly defined. Elevated mean corpuscular volume (MCV), macrocytosis, is the most typical morphological abnormality induced by excessive ethanol consumption. This paper reviews recent data indicating that acetaldehyde, the first metabolite of ethanol, may play a role in the haematological derangements in peripheral blood cells and in bone marrow of alcoholic patients. Studies in experimental animals and in human alcoholics have shown that acetaldehyde can bind to proteins and cellular constituents forming stable adducts. Elevated adduct levels have been found from the erythrocytes of alcohol abusers, which may also be associated with ethanol‐induced effects in haematopoiesis and adverse consequences in cellular functions.
No association of CRH1 receptor polymorphism haplotypes, harm avoidance and other personality dimensions in alcohol dependence: results from the Munich gene bank project for alcoholism
Authors: Soyka M , Preuss UW , Koller G , Zill P , Hesselbrock V , Bondy B 
Published: April 2004

AbstractBecause corticotrophin‐releasing hormone (CRH) plays a central role in stress regulation, the possible role of CRH1 polymorphism for anxiety‐related personality variables such as harm avoidance possibly associated with alcoholism was studied. The research instruments used to phenotype patients were adopted partly from the US collaborative study of the genetics of alcoholism and include a number of personality inventories such as the temperament and character inventory (TCI). Based on the examination of 170 alcoholic subjects no association was found between CRH1 receptor haplotypes of four single nuclotid polymorphisms (SNPs) and low and high temperament traits of harm avoidance, novelty seeking and reward dependence. The possible implications of these findings are discussed.
Effect of breathing pattern on the pressure‐time product calculation
Authors: Natalini G. , Marchesini M. , Tessadrelli A. , Rosano A. , Candiani A. , Bernardini A. 
Published: April 2004

Background:  The pressure‐time product (PTP) is often used to compare conditions with different breathing patterns. Being the pressure‐time product calculated with pressures changes over a minute, mechanical load and inspiration time per minute should be its main determinants. The aim of this study was to investigate if the method of PTP computation is affected by the breathing pattern when mechanical load and inspiratory time per minute are constant.Methods:  Respiratory mechanics and the PTP developed by the ventilator were calculated in 10 mechanically ventilated patients at three different respiratory rate/tidal volume combinations, provided that minute ventilation and inspiratory time per minute were constant.Results:  The static elastance did not change at different tidal volumes. Despite the constant elastic load over a minute, the elastic PTP showed an increment greater than 200% from the higher to the lower respiratory rate, responsible for approximately 80% of the whole PTP increment. On the contrary a ‘corrected’ elastic PTP (calculated using the square root of the elastic pressure‐time area), the elastic double product of the respiratory system and the mean elastic pressure per minute, did not significantly change.Conclusions:  Changes in breathing pattern markedly affected the PTP independently by the mechanical load and the inspiratory time per minute. In these conditions it could not correctly estimate the metabolic cost of breathing. The use of a ‘corrected’ PTP, the mean inspiratory pressure per minute or the double product of the respiratory system, could overcome this limitation.