bluuebunny/crossref_metadata_2025_split huggingface dataset:
Telic Reflections: Interactional Processes, as Such
Authors: Perinbanayagam R. S. 
Published: February 2004

Interactional processes, conducted through symbols of various kinds, are the primal events in human life and, therefore, the primary site also for all social scientific inquiries. The implications of such a claim for a variety of sociological issues are then examined: the “individual” should be conceptualized as an interactive agent; the symbolic processes that she or he undertakes are both pragmatic and artistic exercises; selves emerge out of such exercises and face various “contingencies” as the individuals who bear them advance through various trajectories of their lives, each such moment having its own telos, just as the trajectory will have its particular telic process.only in silence the wordonly in dark the light,only in dying lifebright the hawk's flighton the empty sky—Ursula Le Guin
A family with X‐linked recessive fusion of metacarpals IV and V
Authors: Lonardo Fortunato , Della Monica Matteo , Riccardi Giovanni , Riccio Ilaria , Riccio Vincenzo , Scarano Gioacchino 
Published: January 2004

AbstractWe describe a family with a distinctive malformation of the hand consisting of the fusion of the 4th and the 5th metacarpal bones. Usually this anomaly is clinically recognizable by an ulnar deviation of the 5th finger; moreover, the 5th metacarpal is usually hypoplastic and the 5th ray is consequently short. There is, however, great variability in expression, so the degree of fusion may range from minimal to complete and also the external aspect of the hand may vary. This anomaly can be either isolated or part of a syndrome. For the isolated form, two possible hereditary mechanisms have been proposed: autosomal dominant and X‐linked recessive. Our family is consistent with the latter, with only affected males and no instances of male‐to‐male transmission. Of note, there are very few X‐linked recessive disorders that affect the hand in a such a specific way. © 2003 Wiley‐Liss, Inc.
Specific clinical and brain MRI features in mentally retarded patients with mutations in the Oligophrenin‐1 gene
Authors: Portes Vincent des , Boddaert Nathalie , Sacco Silvia , Briault Sylvain , Maincent Kim , Bahi Nadia , Gomot Marie , Ronce Nathalie , Bursztyn Joseph , Adamsbaum Catherine , Zilbovicius Monica , Chelly Jamel , Moraine Claude 
Published: January 2004

AbstractOligophrenin‐1 (OPHN‐1) gene disruption is known as responsible for so called “non‐specific” X‐linked mental retardation (MR) Billuart et al. [1998: Nature 392:923–926]. In order to search for a possible specific clinical and radiological profile for mutation in the OPHN‐1 gene, clinical and 3D brain MRI studies were performed in the two families with a known mutation in OPHN‐1 reported so far: a 19‐year‐old female with an X;12 balanced translocation encompassing OPHN‐1, and four affected males of family MRX60 sharing a frameshift mutation in OPHN‐1. Clinical data shared by affected individuals were neonatal hypotonia with motor delay but no obvious ataxia, marked strabismus, early onset complex partial seizures, and moderate to severe MR. Brain MRIs performed in three individuals exhibited a specific vermian dysgenesis including an incomplete sulcation of anterior and posterior vermis with the most prominent defect in lobules VI and VII. In addition, a non‐specific cerebral cortico‐subcortical atrophy was also observed. These clinical and radiological features suggest a distinct clinico‐radiological syndrome. These preliminary data need to be confirmed in other families and will be helpful for further targeted mutation screening of the OPHN‐1 gene in male patients with similar clinico‐radiological features. In addition, OPHN‐1 inactivation should be considered as a relevant model of developmental vermis disorganization, leading to a better understanding of the possible role of the cerebellum in MR. © 2003 Wiley‐Liss, Inc.
Clinical variability in maternally inherited leber hereditary optic neuropathy with the G14459A mutation
Authors: Tarnopolsky Mark A. , Baker Steven K. , Myint Tomoko , Maxner C.E. , Robitaille J. , Robinson Brian H. 
Published: January 2004

AbstractSpasticity and dystonia have been associated with mitochondrial (mt) DNA mutations at A11696G, G14459A, and T14596A. We describe the clinical features and molecular analysis of two Caucasian pedigrees with the 14,459 guanosine (G) → adenine (A) transition. The maternally inherited Leber hereditary optic neuropathy (LHON) phenotypes showed extreme clinical variability and the only screening test that was abnormal in the patient with spasticity/dystonia was a high T2 signal in the putamen bilaterally. The male patient in the second pedigree showed features of optic neuropathy without spasticity/dystonia. These results further support that the 14,459 G → A transition mutation is causally related to LHON and spasticity/dystonia. © 2003 Wiley‐Liss, Inc.
Design, Synthesis, and Properties of Molecule‐Based Assemblies with Large Second‐Order Optical Nonlinearities
Authors: Marks Tobin J. , Ratner Mark A. 
Published: January 2004

AbstractThe design, synthesis, characterization, and understanding of new molecular and macromolecular assemblies with large macroscopic optical nonlinearities represents an active field of research at the interface of modern chemistry, physics, and materials science. Challenges in this area of photonic materials typify an important theme in contemporary chemistry: to create new types of functional materials by the rational construction of supramolecular assemblies exhibiting preordained collective phenomena by virtue of “engineered” molecule–molecule interactions and spatial relationships. This review surveys several approaches to, and the microstructural and optical properties of, second‐order nonlinear optical materials built from noncentrosymmetric assemblies of chromophores having large molecular hyperpolarizabilities. Such types of materials can efficiently double the frequency of incident light, exhibit other second‐order nonlinear optical effects, and contribute to the knowledge base needed for new photonic device technologies. Systems described include chromophore macromolecule guesthost matrices, chromophore‐functionalized glassy macromolecules, thermally crosslinked chromophore‐macromolecule matrices, and intrinsically acentric self‐assembled chromophoric superlattices.
Calixarenes, Macrocycles with (Almost) Unlimited Possibilities
Authors: Böhmer Volker 
Published: January 2004

AbstractThe condensation reaction betweenp‐tert‐butylphenol and formaldehyde leads in a single step to good yields of cyclic oligomers in which, depending on the reaction conditions, either four, six, or eight phenol units are joined by methylene bridges. The beakerlike shape of the most stable conformation of the tetramer has led to their being given the name “calixarenes” (calix = chalice). Resorcinol can undergo condensation in a similar manner with a variety of aldehydes to afford cyclic tetramers with the same basic structure (the resorcarenes). In both cases the reaction does not require the use of dilution techniques, so that large quantities of product can be readily obtained. In addition, the parent compounds can be modified in various ways, in particular at the phenolic hydroxy groups or the phenyl residues; these approaches can be used separately or in combination. Calixarenes are thus ideal starting materials for the synthesis of various types of host molecules and can also act as building blocks for the construction of larger molecular systems with defined structures and functions. Their potential applications range from use as highly specific ligands for analytical chemistry, sensor techniques and medical diagnostics to their use in the decontamination of waste water and the construction of artificial enzymes and the synthesis of new materials for non‐linear optics or for ultrathin layers and sieve membranes with molecular pores.
Stereospecific Olefin Polymerization with Chiral Metallocene Catalysts
Authors: Brintzinger Hans H. , Fischer David , Mülhaupt Rolf , Rieger Bernhard , Waymouth Robert M. 
Published: January 2004

AbstractCurrent studies on novel, metallocenebased catalysts for the polymerization of α‐olefins have far‐reaching implications for the development of new materials as well as for the understanding of basic reaction mechanisms responsible for the growth of a polymer chain at a catalyst center and the control of its stereoregularity. In contrast to heterogeneous Ziegler–Natta catalysts, polymerization by a homogeneous, metallocene‐based catalyst occurs principally at a single type of metal center with a defined coordination environment. This makes it possible to correlate metallocene structures with polymer properties such as molecular weight, stereochemical microstructure, crystallization behavior, and mechanical properties. Homogeneous catalyst systems now afford efficient control of regio‐ and stereoregularities, molecular weights and molecular weight distributions, and comonomer incorporation. By providing a means for the homo‐ and copolymerization of cyclic olefins, the cyclopolymerization of dienes, and access even to functionalized polyolefins, these catalysts greatly expand the range and versatility of technically feasible types of polyolefin materials.For corrigendum see DOI:10.1002/anie.199513681
Vibrational Spectroscopy in Supercritical Fluids: From Analysis and Hydrogen Bonding to Polymers and Synthesis
Authors: Poliakoff Martyn , Howdle Steven M. , Kazarian Sergei G. 
Published: January 2004

AbstractSupercritical fluids are beginning to be used widely in chemistry. Applications range from extraction and chromatography in analytical chemistry to solvents for reaction chemistry and preparation of new materials. Spectroscopic monitoring is important in much of supercritical chemistry, and vibrational spectroscopy is particularly useful in this context because the vibrational spectrum of a given molecule is usually quite sensitive to the environment of that molecule. Thus, vibrational spectra are excellent probes of conditions within the fluid. In this review, we describe a variety of techniques and cells for IR and Raman spectroscopy in supercritical fluids and illustrate the breadth of applications in supercritical fluids. The examples include: the use of supercritical Xe as a spectroscopically transparent solvent for chemistry and for supercritical fluid chromatography with FTIR detection of analytes; Raman spectroscopy as a monitor for gases dissolved in supercritical CO2; the effect of solvent density on hydrogen bonding in supercritical fluids and the formation of reverse micelles; IR as a monitor for the supercritical impregnation/extraction of polymers and the reactions of organometallic compounds impreganated into polymers; reactions of organometallic compounds in supercritical fluids; and finally, the use of miniature flow reactors for laboratory‐scale preparative chemistry. Overall, our aim is to provide a starting point from which individual readers can judge whether such measurements might usefully be applied to their own particular problems.
Molecular Imprinting in Cross‐Linked Materials with the Aid of Molecular Templates— A Way towards Artificial Antibodies
Authors: Wulff Günter 
Published: January 2004

AbstractCan binding sites be produced in organic or inorganic polymers—similar to those in antibodies—which are able to recognize molecules and which may have catalytic action? In this article we review a method, analogous to a mechanism of antibody formation proposed earlier, by which in the presence of interacting monomers a cross‐linked polymer is formed around a molecule that acts as a template. After removal of the template, an imprint containing functional groups capable of chemical interaction remains in the polymer. The shape of the imprint and the arrangement of the functional groups are complementary to the structure of the template. If chiral templates are used, the success of the imprinting process can be assessed by the ability of the polymer to resolve the racemate of the template molecule. Through optimization of the process has led to chromatographic separation factors of α = 4–8, and to base line separations. There is also great interest in the surface imprinting of solid materials and monolayers. In all cases, the structure of the polymeric matrix in the imprinted materials and the function of the binding groups are of crucial importance. The mechanisms of imprinting and molecular recognition of substrates are by now well understood. A large number of potential applications for this class materials are being intensively developed, for example in the chromatogrphic resolution of recemates, and as artificial antibodies, chemosensors, and selective catalysts. The use of similarly produced materials as enzyme models is also of great interest.
Synthetic Aspects of Metal‐Catalyzed Oxidations of Amines and Related Reactions
Authors: Murahashi Shun‐Ichi 
Published: January 2004

AbstractThe metabolism of amines is governed by a variety of enzymes such as amine oxidase, flavoenzyme, and cytochrome P‐450. A wide variety of compounds are produced such as ammonia and alkaloids in selective and clean oxidation reactions that proceed under mild reaction conditions. Simulation of the functions of these enzymes with simple transition metal complex catalysts may lead to the discovery of biomimetic, catalytic oxidations of amines and related compounds. Indeed, metal complex catalyzed oxidations have been found to proceed with high efficiency. The first section of this review discusses the dehydrogenative oxidations of amines with transition metal catalysts by transition metal catalysts that simulate amine oxidase. The second section highlights the catalytic oxidation of secondary amines to nitrones by simulation of flavoenzymes. The third section describes the simulation of the function of cytochrome P‐450 with lowvalent ruthenium complexes and peroxides. Biomimetic ruthenium‐catalyzed oxidations of tertiary amines, secondary amines, and other substrates such as amides, β‐lactams, nitriles, alcohols, alkenes, ketones, and even nonactivated hydrocarbons can be performed selectively under mild conditions. These three general approaches provide highly useful strategies for synthesis of fine chemicals and biologically active compounds such as alkaloids, amino acids, and β‐lactams.
Electronegativity and Molecular Properties
Authors: Bergmann D. , Hinze Juergen 
Published: January 2004

AbstractThe paradigm that the properties of the atoms determine the properties of the molecules that they form is systematically presented. To this end, three types of atomic properties are differentiated: (a) those that can be determined directly by spectroscopy, (b) those based on theoretical concepts, and (c) those that can be assigned to the atoms interacting in molecules. On the basis of the electronegativity values of the atoms, which can be determined from spectroscopic data together with the assumption that the electronegativities are equalized in bonds, partial charges of the atoms in molecules are determined. These partial charges are correlated with ESCA data and proton affinities. In addition, simple expressions are given for the reliable estimation of bond lengths, bond energies, and force constants.For corrigendum see DOI:10.1002/anie.199607811
Stereocontrol in Organic Synthesis Using the Diphenylphosphoryl Group
Authors: Clayden Jonathan , Warren Stuart 
Published: January 2004

AbstractIn 1959, Horner showed that metalated alkyldiphenylphosphane oxides react with aldehydes or ketones to give alkenes. With this reaction, the diphenylphosphoryl (Ph2PO) group made its entrance into synthetic organic chemistry. In the thirty‐six years since that date, extensive research has shown that this olefination, the Horner–Wittig reaction, has unique properties that make it much more than simply the phosphane oxide cousin of the more famous phosphorus‐based olefinations—the Wittig reaction (based on phosphonium salts) and the Wadsworth–Emmons reaction (based on phosphonate esters). Early work on the Horner–Wittig reaction concentrated on the reactivity of phosphane oxides and the regioselectivity of their reactions, but more recently the power of the Ph2PO group to control the stereochemistry of alkenes, and to produce “on demand” either stereoisomer in high stereochemical purity, has emerged. From the study of these stereocontrolled Horner–Wittig reactions arose the realization that the Ph2PO group is useful not only for the control of the two‐dimensional stereochemistry of alkenes, but also of three‐dimensional stereochemistry in general.After a brief introduction to phosphane oxide chemistry, this review will examine the Horner–Wittig reaction, in both its original and “stereocontrolled” varieties. From there, we will move on to an account of the stereoselective construction of molecules containing the Ph2PO group, concentrating on the stereochemical directing effects of the Ph2PO group and on the role of its unique combination of attributes—steric bulk, electronegativity, and Lewis basicity—in controlling these reactions. Finally, we will present what is intended as a practical guide to this chemistry, covering the type of functionalized alkenes that have been made with the help of the Ph2PO group and giving guidelines that we hope will help the organic chemist to make the most of the chemistry the Ph2PO group has to offer.
Electron Domains and the VSEPR Model of Molecular Geometry
Authors: Gillespie Ronald J. , Robinson Edward A. 
Published: January 2004

AbstractThe valence shell electron pair repulsion (VSEPR) model—also known as the Gillespie–Nyholm rules—has for many years provided a useful basis for understanding and rationalizing molecular geometry, and because of its simplicity it has gained widespread acceptance as a pedagogical tool. In its original formulation the model was based on the concept that the valence shell electron pairs behave as if they repel each other and thus keep as far apart as possible. But in recent years more emphasis has been placed on the space occupied by a valence shell electron pair, called the domain of the electron pair, and on the relative sizes and shapes of these domains. This reformulated version of the model is simpler to apply, and it shows more clearly that the Pauli principle provides the physical basis of the model. Moreover, Bader and his co‐workers' analysis of the electron density distribution of many covalent molecules have shown that the local concentrations of electron density (charge concentrations) in the valence shells of the atoms in a molecule have the same relative locations and sizes as have been assumed for the electron pair domains in the VSEPR model, thus providing further support for the model. This increased understanding of the model has inspired efforts to examine the electron density distribution in molecules that have long been regarded as exceptions to the VSEPR model to try to understand these exceptions better. This work has shown that it is often important to consider not only the relative locations and sizes, but also the shapes, of both bonding and lone pair domains in accounting for the details of molecular geometry. It has also been shown that a basic assumption of the VSEPR model, namely that the core of an atom underlying its valence shell is spherical and has no influence on the geometry of a molecule, is normally valid for the nonmetals but often not valid for the metals, including the transition metals. The cores of polarizable metal atoms may be nonspherical because they include nonbonding electrons or because they are distorted by the ligands, and these nonspherical cores may have an important influence on the geometry of a molecule.
Electrospray Mass Spectrometry of Biomacromolecular Complexes with Noncovalent Interactions—New Analytical Perspectives for Supramolecular Chemistry and Molecular Recognition Processes
Authors: Przybylski Michael , Glocker Michael O. 
Published: January 2004

AbstractThe development of “soft” ionization methods in recent years has enabled substantial progress in the mass spectrometric characterization of macromolecules, in particular important biopolymers such as proteins and nucleic acids. In contrast to the still existing limitations for the determination of molecular weights by other ionization methods such as fast atom bombardment and plasma desorption, electrospray ionization (ESI) and matrix‐assisted laser desorption have provided a breakthrough to macromolecules larger than 100 kDa. Whereas these methods have been successfully applied to determine the molecular weight and primary structure of biopolymers, the recently discovered direct characterization by ESI‐MS of complexes containing noncovalent interactions (“noncovalent complexes”) opens new perspectives for supramolecular chemistry and analytical biochemistry. Unlike other ionization methods ESI‐MS can be performed in homogeneous solution and under nearly physiological conditions of pH, concentration, and temperature. ESI mass spectra of biopolymers, particularly proteins, exhibit series of multiply charged macromolecular ions with charge states and distributions (“charge structures”) characteristic of structural states in solution, which enable a differentiation between native and denatured tertiary structures. In the first part of this article, fundamental principles, the present knowledge about ion formation mechanism(s) of ESI‐MS, the relations between tertiary structures in solution and charge structures of macro‐ions in the gas phase, and experimental preconditions for the identification of noncovalent complexes are described. The hitherto successful applications to the identification of enzyme–substrate and –inhibitor complexes, supramolecular protein–and protein–nucleotide complexes, double‐stranded polynucleotides, as well as synthetic self‐assembled complexes demonstrate broad potential for the direct analysis of specific noncovalent interactions. The present results suggest new applications for the characterization of supramolecular structures and molecular recognition processes that previously have not been amenable to mass spectrometry; for example, the sequence‐specific oligomerization of polypeptides, antigen–antibody complexes, enzyme–and receptor–ligand interactions, and the evaluation of molecular specificity in combinatorial syntheses and self‐assembled systems.