bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microwave Spectroscopy of Large Molecules and Molecular Complexes
Authors: Caminati Walther 
Published: September 2011

AbstractThe development of Fourier transform microwave (FTMW) spectroscopy and — most notably — its combination with supersonic‐jet expansion techniques allow for challenging investigations of larger and larger interesting molecular systems.Large isolated molecules studied by microwave (MW) spectroscopy include long carbon chains of astronomical interest, organic molecules containing two or more aromatic rings, small biomolecules, and transition metal complexes. Often, these systems are characterized by large‐amplitude motions and multifolded conformational and tautomeric equilibria.Rotational spectra have been reported for many large molecular complexes, such as adducts of large organic and biological molecules with rare gases, water (or other small proton donors/acceptors), and oligomers and hetero adducts of large molecules. Some of these complexes have interaction energies that are in the intermediate regime between bonding and nonbonding (charge‐transfer complexes), and some of them, involving chiral molecules, act as a guide to understanding molecular recognition. In addition, the rotational spectra of several carbonyl sulfide (OCS)Henspecies have been measured (up ton = 39), providing useful data to model superfluidity.The potentiality of MW spectroscopy to obtain spectroscopic and chemical information on these systems is demonstrated by numerous investigations. Many interesting examples, most of them achieved in the last two decades, have been compiled here.
High‐resolution Microwave and Infrared Spectroscopy of Molecular Cations
Authors: Amano Takayoshi 
Published: September 2011

Abstract

High‐resolution spectroscopic results for molecular cations obtained in the wavelength regions from microwave to infrared are summarized, with emphasis on more recent developments made after the year 2000. Starting at some early stage development made with mostly discharge sources, various experimental techniques developed for the detection of ions are discussed in some details. Recent results on specific molecular ions such as H
3
+
and H
3
O
+
and their isotopic species are reviewed to show what kind of information could be obtained with high‐resolution spectroscopic techniques. The current status on a most challenging species in this field, CH
5
+
, is described. Applications to and implications from astronomical observations are also described wherever they are relevant to spectroscopy.
Rotationally Resolved Electronic Spectroscopy and Automatic Assignment Techniques using Evolutionary Algorithms
Authors: Schmitt Michael , Meerts W. Leo 
Published: September 2011

AbstractThe usefulness of an evolutionary algorithm (EA)‐based approach to the automated evaluation of molecular parameters from various kinds of spectra is shown. The applicability of the method ranges from rotationally resolved electronic spectroscopy of large molecules to nuclear magnetic resonance (NMR) spectroscopy of molecules, which are partially oriented in an anisotropic liquid‐crystalline environment. The application of both the genetic algorithm (GA) and the evolution strategy algorithm (ES) approaches for the assignment of complex spectra and the necessity of fitting meta parameters, which are not related to the parameters of the model describing the spectra are discussed. Examples for the possible applications comprise rovibronic spectra of various aromatic water clusters, rovibronic spectra of large hetero‐ and homo‐dimers, rovibrational spectra of the NH stretching vibrations in different tautomers of benzotriazole, and the NMR spectrum ofp‐bromo‐biphenyl dissolved in a nematic crystal.
High‐resolution Valence‐shell Photoionization
Authors: Pratt Stephen T. 
Published: September 2011

AbstractThis article presents a brief review of high‐resolution, valence‐shell photoionization studies of diatomic and small polyatomic molecules. Both single‐photon ionization of ground‐state molecules and multiphoton/multistep ionization of excited‐state molecules are discussed, and the complementary nature of the two approaches is emphasized. Although direct photoionization processes are discussed, the principal focus of the article is on resonance phenomena such as autoionization and predissociation, with a particular emphasis on the former. The various forms of autoionization are illustrated by using examples from recent work on H2, H3, N2, NO, CO2, and other molecules.
Fundamentals of Electronic Spectroscopy
Authors: Wörner Hans J. , Merkt Frédéric 
Published: September 2011

AbstractThe basic principles of electronic spectroscopy of atoms and molecules in the gas phase are presented. In the first part, the elementary concepts necessary to describe the electronic structure of atoms, diatomic molecules, and polyatomic molecules are introduced in a systematic manner, with an effort to classify the different interactions (electrostatic, spin–orbit, hyperfine) and types of motions (electronic, vibrational, rotational), which determine the energy level structures. In the second part, electronic transitions are discussed, with their spin‐rovibrational structures. Examples ranging from the simple band structure of\documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\pagestyle{empty}\begin{document}$\rm{\Sigma}^{+}_{{{\rm u}}}\leftarrow \rm{\Sigma}_{{{\rm g}}}^{+}$\end{document}electronic transitions of homonuclear diatomic molecules to the highly complex band structure of polyatomic molecules subject to strong vibronic interactions are used to illustrate the richness of electronic spectra.
Orders of Magnitude and Symmetry in Molecular Spectroscopy
Authors: Oka Takeshi 
Published: September 2011

AbstractConsiderations of the order of magnitude and the symmetry of various intramolecular interactions form the foundation of molecular spectroscopy. They are related and they together make molecular spectroscopy transparent and tidy. In this chapter, they are discussed starting from the very fundamental. The order of magnitude has not been discussed in any previous textbooks of molecular spectroscopy. The symmetry has been discussed in many textbooks and discussions here are limited to the rotational and nuclear spin states and its application to forbidden rotational transitions and the stability of nuclear spin modifications (ortho‐, para‐ etc.).
Fundamental Symmetries and Symmetry Violations from High Resolution Spectroscopy
Authors: Quack Martin 
Published: September 2011

AbstractAfter an introductory survey, we introduce the seven fundamental symmetries of physics in relation to the group of the molecular Hamiltonian and the current standard model of particle physics (SMPP). We discuss the relation of these symmetries to conservation laws and fundamentally nonobservable properties of nature with the example of parity violation. The particular importance of experiments on detecting symmetry breakings is outlined and the three distinct, basic concepts of symmetry breaking (spontaneous,de facto,de lege) are illustrated with the example of space inversion symmetry breaking and parity violation in chiral molecules. Similar conceptual situations are found for our understanding of the underlying physics of molecular chirality by various types of symmetry breakings, of the evolution of biomolecular homochirality and of irreversibility as breaking of time reversal symmetry. The current status of the quantitative theory of molecular parity violation in the framework of electroweak quantum chemistry is reviewed, including the change of order of magnitude, which was found in recent years and has since been confirmed repeatedly.The concepts of high‐resolution spectroscopic experiments on parity violation in chiral molecules are discussed and the status of current attempts toward detecting molecular parity violation is summarized with particular emphasis on the possibilities of measuring time‐dependent parity violation in the exceptional (still hypothetical) unstable parity isomers of chiral molecules. The concept of successive symmetry breakings in the quantum dynamics of molecules is illustrated with the wide range of time‐scales for symmetry‐breaking processes ranging from femtoseconds in experiments on very fast intramolecular vibrational redistribution (IVR) to the theoretical times of seconds for molecular parity violation.The role of approximate symmetries and conservation laws for our understanding of selection rules in spectroscopy and in chemical reaction dynamics is analyzed in some detail with the example of approximate parity and nuclear spin symmetry conservation in radiative and reactive molecular processes. This includes the use of permutation‐inversion symmetry groups in applications to spectroscopy and state‐selected chemical reactions. Statistical concepts for the description of molecular energy levels are presented for use in high‐resolution spectroscopy and chemical reactions in relation to symmetry properties.We conclude with a summary of the current status of the following symmetries and their violations in spectroscopy and molecular dynamics: nuclear spin symmetry in chemical processes, space inversion symmetry and parity violation in chiral molecules, time reversal symmetry in intramolecular processes, and combined charge conjugation, parity, and time reversal (CPT) symmetry in relation to more fundamental aspects of time reversal and speculations on mass differences in chiral molecules and chiral neutrinos and their antimatter counterparts.
High‐resolution Infrared–Ultraviolet (IR–UV) Double‐resonance Spectroscopy of Biological Molecules
Authors: Stanca‐Kaposta E. Cristina , Simons John P. 
Published: September 2011

AbstractTunable infrared (IR) laser excitation of small biomolecules entrained in an expanding supersonic jet, or of biomolecular ions held in a cooled ion trap, provides a powerful means of isolating them at low temperatures in the gas phase and probing their vibrational spectroscopy at high resolution. Many alternative experimental strategies have been devised to achieve this. The article reviews their development and presents some representative benchmark examples of their application.
Room Temperature Multifunctional Organophosphorus Gels and Liquid Crystals
Authors: Romero‐Nieto Carlos , Marcos Mercedes , Merino Sonia , Barberá Joaquín , Baumgartner Thomas , Rodríguez‐López Julián 
Published: September 2011

AbstractA new series of extended dithieno[3,2‐b:2',3'‐d]phospholes with dendritic and non‐dendritic architectures involving phenylenevinylene as well as Fréchet‐type dendrons is presented. Modification of the phosphorus center with Pd allows for the generation of a dimeric dendrimer with Pd‐center. The synthetic strategy employed balances the rigid main scaffold with the flexibility of the dendrons in order to keep control of supramolecular self‐organization features. All the structures show a high photoluminescence in both solution and solid state, which is further intensified via energy transfer from the dendrons to the core. In terms of self‐organization in solution, three of the derivatives which bear an extended phosphole unit as common moiety are able to gel a variety of organic solvents at room temperature independently from the nature of their substituents. Notwithstanding, the dimeric dendrimer with Fréchet‐type dendrons is only able to display gel properties at low temperature. All gels exhibit pronounced photoluminescence properties that can be tuned by variation of the solvent and the temperature. In absence of solvent, the phosphole derivatives exhibit, moreover, liquid‐crystalline mesomorphism features. While three of the compounds present stable and highly luminescent columnar hexagonal phases at room temperature, the fourth species was found to be crystalline in the thermal range up to its isotropic state. Finally as proof of concept, the multifunctionality of these materials is demonstrated in an electrochromic device.
Molecular Self‐Assembly at Solid Surfaces
Authors: Otero Roberto , Gallego José María , de Parga Amadeo L. Vázquez , Martín Nazario , Miranda Rodolfo 
Published: September 2011

AbstractSelf‐assembly, the process by which objects initially distributed at random arrange into well‐defined patterns exclusively due to their local mutual interactions without external intervention, is generally accepted to be the most promising method for large‐scale fabrication of functional nanostructures. In particular, the ordering of molecular building‐blocks deposited at solid surfaces is relevant for the performance of many organic electronic and optoelectronic devices, such as organic field‐effect transistors (OFETs), organic light‐emitting diodes (OLEDs) or photovoltaic solar cells. However, the fundamental knowledge on the nature and strength of the intermolecular and molecule‐substrate interactions that govern the ordering of molecular adsorbates is, in many cases, rather scarce. In most cases, the structure and morphology of the organic‐metal interface is not known and it is just assumed to be the same as in the bulk, thereby implicitly neglecting the role of the surface on the assembly. However, this approximation is usually not correct, and the evidence gathered over the last decades points towards an active role of the surface in the assembly, leading to self‐assembled structures that only in a few occasions can be understood by considering just intermolecular interactions in solid or gas phases. In this work we review several examples from our recent research demonstrating the apparently endless variety of ways in which the surface might affect the assembly of organic adsorbates.
On a sustainability interval index and its computation through global optimization
Authors: Conner Jeremy A. , Phillis Yannis A. , Manousiouthakis Vasilios I. 
Published: September 2011

AbstractPrior sustainability models have taken exact basic indicator (BI) values of an entity's sustainability and computed an exact value of the entity's sustainability index. However, BI values are either uncertain or difficult to obtain. In this work, we propose a novel approach that transforms BI data in the form of intervals containing all possible BI values to an interval containing all possible values of the sustainability index. This interval is termed the “sustainability index interval” (SII). Computation of the SII is achieved through solution of a minimization and a maximization problem using global optimization techniques. Although the underlying global optimization problems are nonconvex, they are shown to possess a number of properties that can be utilized to reduce the burden associated with SII's computation. Based on these properties, a branch‐and‐bound algorithm is developed, which exactly quantifies the SII in a finite number of iterations. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Effects of SCH 486757, A Nociceptin‐1 Receptor Agonist, on Fertility and Reproductive Hormone Levels in Female CRL:CD®[SD] Rats
Authors: Enright Brian P. , McIntyre Barry S. , Barat Stephen A. , Treinen Kimberley A. , Kopytek Stephan J. 
Published: September 2011

AbstractBACKGROUNDSCH 486757 is a nociceptin‐1 receptor agonist that was in development as an antitussive. Studies were conducted to characterize its effects on female fertility and to examine its potential modes of action.METHODSFemale rats were administered up to 20 mg/kg SCH 486757 before/during mating through gestation day (GD) 7; female fertility and embryonic development were assessed on GD 14. In a subsequent study, pregnant rats were dosed up to 50 mg/kg SCH 486757 from GD 0 to 7. Reproductive hormones were assessed on GD 1, 3, 5, and 7, and embryonic development was assessed on GD 14. A subset of dosed dams were allowed to deliver, were subsequently re‐mated, and reproductive hormones and fertility were assessed on GD 7 and 14, respectively. To determine the effects of SCH 486757 on nonpregnant rats, doses of up to 50 mg/kg SCH 486757 were administered for 4 days beginning on the day of estrus; reproductive hormones were assessed after the final dose.RESULTSFemale rats administered ≥20 mg/kg SCH 486757 exhibited abnormal estrous cycles; decreased fertility, number of corpora lutea, and implantation sites; and increased pre‐ and postimplantation loss. In general, administration of SCH486757 was associated with lower luteinizing hormone (LH) progesterone (P4), and estradiol (E2) levels in pregnant rats. These effects on fertility/embryonic development and reproductive hormones exhibited reversibility post dosing. Nonpregnant rats in the 50‐mg/kg group exhibited apparent decreases in P4 and E2 levels, with no apparent effects on LH values.CONCLUSIONSThe SCH 486757‐related effects on fertility and embryonic development were likely the result of decreases in P4, E2, and/or LH, rather than being due to decreased prolactin levels.
Phenolic Compounds from Selaginella moellendorfii
Authors: Wu Bin , Wang Jia 
Published: September 2011

AbstractChemical investigation of the leaves and roots of Selaginella moellendorfii Hieron has resulted in the isolation and characterization of two new flavone glucosides, 7‐O‐(β‐glucopyranosyl(1→2)‐[β‐glucopyranosyl(1→6)]‐β‐glucopyranosyl)flavone‐3′,4′,5,7‐tetraol (1) and 7‐O‐(β‐glucopyranosyl(1→2)‐[β‐glucopyranosyl(1→6)]‐β‐glucopyranosyl)flavone‐4′,5,7‐triol (2), two new biflavonoids, 2,3‐dihydroflavone‐5,7,4′‐triol‐(3′→8″)‐flavone‐5″,6″,7″,4′′′‐tetraol (3) and 6‐methylflavone‐5,7,4′‐triol‐(3′→O→4′′′)‐6″‐methylflavone‐5″,7″‐diol (4), two new lignans, (7′E)‐3,5,3′,5′‐tetramethoxy‐8 : 4′‐oxyneolign‐7′‐ene‐4,9,9′‐triol (5) and 3,3′‐dimethoxylign‐8′‐ene‐4,4′,9‐triol (6), together with two known monolignans, four known lignans, and four known biflavonoids. Their structures were established by spectroscopic means and by comparison with literature values.
Model‐Based Optimization of Urea Dosage for SCR Catalysts
Authors: Hauptmann Wulf , Schuler Anke , Gieshoff Jürgen , Votsmeier Martin 
Published: September 2011

AbstractEine neue Methode zur modellbasierten Optimierung der zeitabhängigen Harnstoffdosierung für SCR‐Katalysatoren (Selective Catalytic Reduction) wird präsentiert. Es werden Dosierprofile für zwei verschiedene Katalysatoren (Fe‐ und Cu‐Zeolith) berechnet. Dabei zeigt sich, dass die relative Leistungsfähigkeit der beiden Katalysatoren vom gewählten Dosierprofil abhängt. Dies bedeutet, dass ein aussagekräftiger Vergleich zwischen verschiedenen Katalysatoren nur möglich ist, wenn jeder Katalysator mit einer individuell optimierten Harnstoffdosierung getestet wird.
Simulation of the Kinetics from Isotopic Exchange Experiments on Mo/V/W‐Mixed Oxide Catalysts for the Oxidation of Acrolein
Authors: Drochner Alfons , Kampe Philip , Blickhan Nina , Jekewitz Tim , Vogel Herbert 
Published: September 2011

AbstractMittels der Isotopenaustauschmethode SSITKA (steady‐state isotopic‐transient kinetic analysis) ergaben sich Rückschlüsse zum Mechanismus der Partialoxidation von Acrolein zu Acrylsäure an Mo/V/W‐Mischoxidkatalysatoren. Der Isotopenaustausch erfolgte mit den beiden Sauerstoffisotopen 16O2 und 18O2. Dabei findet am Katalysator ein Austausch des Carbonylsauerstoffs im Acrolein mit Festkörpersauerstoff statt. Zusätzlich wird die Kinetik der unterschiedlichen Isotopologenspezies durch eine Austauschreaktion von Sauerstoff zwischen belegten und unbelegten Zentren an der Oberfläche und in der Volumenphase des Katalysators signifikant beeinflusst. Gestützt durch einen erweiterten Modellvorschlag zum Mechanismus konnten über Simulationen die experimentell gewonnenen Isotopologenkinetiken verifiziert werden.
ecoinvent – Consistent, Transparent and Quality‐Ensured Background Database for Life Cycle Assessment & Co
Authors: Hischier Roland 
Published: September 2011

AbstractDie Ökobilanz ist jenes produktbezogene Analysetool zur Beurteilung der ökologischen Nachhaltigkeit, das in den letzten Jahren eine sehr starke Verbreitung gefunden hat. Gründe dafür sind u. a. die immer umfangreicheren Hintergrunddatenbanken, welche für dieses Instrument zur Verfügung stehen. In diesem Beitrag wird die aktuell wohl umfangreichste und transparenteste dieser Datenbanken – die in der Schweiz entwickelte Datenbank ecoinvent – im Detail vorgestellt; und ihre Anwendbarkeit für die chemische Industrie kurz skizziert.
A continuum description of the damage process in the arterial wall of abdominal aortic aneurysms
Authors: Marini Giacomo , Maier Andreas , Reeps Christian , Eckstein Hans‐Henning , Wall Wolfgang A. , Gee Michael W. 
Published: September 2011

SUMMARYIn the present work, we develop a three‐dimensional isotropic finite‐strain damage model for abdominal aortic aneurysm (AAA) wall that considers both the characteristic softening of the material caused by damage and the spatial variation of the material properties. A strain energy function is formulated that accounts for a hyperelastic, slightly compressible, isotropic material behavior during the elastic phase, whereas the damage process only contributes to the material response when the elastic limit of the AAA wall is exceeded. Material and damage parameters are obtained by fitting the strain energy function to the experimental data obtained by uniaxial tensile tests of freshly harvested AAA wall samples. The damage model extends the validity of the material law to a strain range of up to 50%. Purely elastic material laws for AAA wall are only valid for a strain range of up to 17%. In a series of finite element simulations of patient‐specific AAAs, serving as numerical examples, we investigate the applicability of the damage model. The use of the damage model does not yield a more distinct identification of rupture‐prone AAAs than other computational‐based risk indices. However, the benefit of the finite‐strain damage model is the potential capability to trigger growth and remodeling processes in mechanobiological models. Copyright © 2011 John Wiley & Sons, Ltd.
Structural Studies and Cytotoxicity of Trimethyl(ferrocenylmethyl)ammonium Iodide Encapsulated in β‐Cyclodextrin
Authors: Bruno Sofia M. , Fernandes José A. , Marques Joana , Neto Sara C. , Ribeiro‐Claro Paulo J. , Pillinger Martyn , Paz Filipe A. Almeida , Marques Maria Paula M. , Braga Susana S. , Gonçalves Isabel S. 
Published: September 2011

AbstractInclusion complexes that comprise β‐cyclodextrin (β‐CD) and trimethyl(ferrocenylmethyl)ammonium iodide (1) have been prepared by codissolution of the host and guest in ethanol/water, accompanied by either conventional heating at 40 °C for 26 h (to give 2) or microwave‐assisted heating for 30 min (to give 3). Solids were isolated and characterized by elemental and thermogravimetric analyses, powder X‐ray diffraction (XRD), and IR, Raman, and 13C{1H} CP/MAS NMR spectroscopy. Powder XRD indicated the presence of microcrystalline inclusion compounds with supramolecular structures that comprise β‐CD head‐to‐head dimers arranged into infinite channels. A small crop of single crystals of the inclusion compound 2 were obtained and analyzed by XRD. Despite diffraction being very poor above a resolution of around 1 Å, the data could be indexed to the space group P1 (in agreement with powder XRD) and a reasonable structural model could be achieved when the asymmetric unit was composed of two directly located β‐CD hosts, 1.4 iron atoms, and a small fraction of iodide anions. By using these data as a starting point, DFT calculations were carried out and led to a model of the crystal structure that comprised 2:1 (host/guest) and 2:2 adducts. The cytotoxic and antiproliferative activities of 1 and 2 were tested against the breast adenocarcinoma MDA‐MB‐231 and osteosarcoma MG‐63 cell lines. Results indicate that both 1 and 2 are cytotoxic against the MDA‐MB‐231 line but exhibit negligible activity on the MG‐63 line.