bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amorphous Semiconductor‐Electrolyte Junction. A New Interpretation of the Impedance Data of Amorphous Semiconducting Films on Metals
Authors: Quarto Francesco Di , Sunseri Carmelo , Piazza Salvatore 
Published: July 2012

AbstractOn the basis of the theory of amorphous semiconductor Schottky barrier an equivalent electrical circuit of the amorphous oxide film/electrolyte interface is proposed.—The analytical expressions for the equivalent conductance and capacitance of the barrier are reported in the hypothesis of a constant density of states within the mobility gap.—According to this model, the semiconducting properties and the impedance behaviour at different frequencies of anodic oxide films on Niobium are interpreted by taking into account the amorphous nature of the films.—An explanation for the anomalous behaviour of the Mott‐Schottky plots usually observed with amorphous anodic oxide films is presented.—The possible extension of such a model to different metal/anodic oxide/electrolyte junctions is suggested.
Coverage Dependence of CO Electrosorption on Palladium: An in‐situ IR Study
Authors: Solomun T. 
Published: July 2012

AbstractIn situ IR spectra of CO adsorbed onto a smooth polycrystalline Pd electrode in 1 M HCIO4 were obtained as a function of surface coverage. CO surface coverage was obtained by direct electrochemical oxidation of the adsorbed CO. At low coverages a single, broad adsorption band was observed at a vibrational frequency attributed to CO in a three‐coordinate surface site. Three‐coordinated species are completely converted, over a relatively narrow coverage range, into an overlayer comprising CO adsorbed on a two‐coordinate site. This layer coexists with an increasing amount of linearly bonded CO as the coverage is increased up to the saturation value.
Internal Oxidation of Impurities in Palladium Investigated by X‐Ray Absorption Spectroscopy
Authors: Lengeler B. 
Published: July 2012

AbstractThe internal oxidation of thirteen dilute palladium alloys which where oxidized for one hour between 1037 and 1053°C has been investigated by X‐ray absorption spectroscopy. When oxygen‐impurity complexes are formed the K or L3 absorption edges of the impurities are shifted to higher energies. The structural details of the complexes formed were studied by means of the corresponding EXAFS. Pt, Au, Pb and Bi form no impurity‐oxygen‐complexes. All other impurities investigated (Y, Zr, Nb, Mo, Gd, Yb, Lu, Hf, Th) are oxidized to the highest state of oxidation. Most of them form well‐crystallized oxides (Y2O3, Nb2O5, Gd2O3, Yb2O3, Lu2O2, HfO2, ThO2). Zr and Mo form only poorly crystallized precipitates in which only one or two shells around the impurities are visible.
The Endoperoxide of Mesodiphenylhelianthrene. Four Reaction Channels Leading from Different Upper Excited Electronic States to Cycloreversion
Authors: Schmidt R. 
Published: July 2012

AbstractThe photocycloreversion of the endoperoxide of mesodiphenylhelianthrene (MDHPO) regenerating the parent hydrocarbon and oxygen has been investigated at ten different irradiation wavelengths. A marked stepwise energy dependence with four almost energy independent plateaus has been observed for the quantum yield Q. A correlation between the step energies and the singlet state energies of MDHPO indicates that the extraordinary energy dependence of Q is a result of four different reaction channels which originate from different thermally equilibrated Sn (n ≥ 2) singlet states and lead to cycloreversion. The quantum yield of each reaction channel has been calculated. The correlation between these values and the corresponding internal conversion energy gaps supports this interpretation.
Thermally Oxidized Iron Electrodes for Photoelectrochemical Application
Authors: Antonucci V. , Passalacqua  , Giordano N. 
Published: July 2012

AbstractAir‐oxidized and CO2‐treated laminar iron electrodes have been characterized structurally (X‐ray diffraction) and photoelectrochemically (photocurrent, polarization, cyclic voltammetry, flat‐band and static potential, band‐gap and cell characteristics) in order to elucidate the role of Fe2+ and Fe3+ at the semiconductor‐electrolyte interface in the photooxidation of H2O. Surface Fe2+ increases the band‐gap and the electron‐hole recombination rate; Fe3+ causes electroreduction of O2, which is followed by oxidation of Fe2+ (Fe3O4 → Fe2O3). This affects the catalytic activity for dissociative water adsorption as Fe2+ on non‐stoichiometric α‐Fe2O3 acts as the active site.
Modellierung in der Verfahrenstechnik am Beispiel von Kristallisatoren
Authors: Mersmann A. , Kind M. 
Published: July 2012

AbstractThe understanding of the physical and chemical principles which govern a process is the presupposition for the design of apparatusses and plants. A process is understood, if the balances can be formulated completely, if the equilibria are known and if kinetic effects are considered correctly.—By the example of mass crystallisation from solution it is shown how balances have to be formulated for mass, energy and population density. The last of these three balances requires to consider mixing as well as kinetics. Kinetics means growth, nucleation and for example effects due to attrition because of mechanical stress applied to the crystals.—All these aspects together lead to a designing method for crystallizers which is reliable and predictive. Unfortunately, up to now not all kinetic parameters needed for design arc available.
Distinction Between Deterministic Chaos and Amplification of Statistical Noise in an Experimental System
Authors: Freund A. , Kruel Th. , Schneider F. W. 
Published: July 2012

AbstractThe self‐oscillating Belousov‐Zhabotinsky reaction is investigated in a CSTR for preequilibrated reactant solutions as a function of stirring rate and flow rate by recording the Ce4+ absorption as a function of time over about 200 oscillations. The oscillations display deterministic chaos particularly at high flow rates as shown by the broad‐band Fourier spectra, the strangeness of the attractors, the fractal information dimension (DI = 1.22) whose imbedding dimension is 5, and the positive Lyapounov exponents. On the basis of our computer calculations a criterion for the distinction between deterministic chaos and amplified statistical noise is proposed. This criterion is the dependence of
the average largest Lyapounov exponent on the stirring rate in the CSTR. The average largest Lyapounov exponent is positive and constant for chaos whereas it should extrapolate to zero for amplified statistical fluctuations in the limit of high stirring rates.
Dynamic Liquid State NMR and IR Study of Tautomerism and Conformations of Tetraphenyloxalamidine, a Novel Small Intramolecular Double Hydrogen Transfer System
Authors: Otting Gottfried , Rumpel Helmut , Meschede Ludger , Scherer Gerd , Limbach Hans‐Heinrich 
Published: July 2012

AbstractUsing Dynamic NMR Spectroscopy we have detected a novel intramolecular double hydrogen transfer in the oxalamidine (OA) system. OA is, therefore, so far the smallest known molecular unit capable of such a transfer. Because of solubility problems, experiments were performed on tetraphenyloxalamidine (TPOA, Ia) and the isotopically labeled compound TPOA‐15N4‐d20(Ib) dissolved in CD2CI2. At low temperatures TPOA exists in a number of different conformations, of which only one conformation with two intramolecular hydrogen bonds is capable of an intramolecular hydrogen transfer which shows up in the1H‐15N signal of this conformer. At low temperatures a1H‐15N doublet (88 Hz coupling constant) is observed which changes into a triplet (44 Hz coupling constant) as the temperature is raised. The position of this signal is independent of temperature and concentration. Two further conformations were detected, of which one formed strong intermolecular hydrogen bonds and underwent fast intermolecular proton exchange. Above room temperature all NH signals coalesce into an exchange‐broadened singlet.13C experiments prove that this effect is due to a fast internal conversion of all conformers. IR experiments on TPOA in CCl4did not reveal the complicated conformational behavior of TPOA. By lineshape analysis we obtained the rate constants of the HH migration, which are given by kHH= 1010.8exp(−43 kJ mol−1/RT). An upper limit for the HD exchange rates were found for a sample deuterated to 90% in the labile proton sites:kHD= exp(−53 kJ mol−1/RT), i.e.kHH/kHD= 2.1 at 298 K. The data are compared to previous results on the azophenine rearrangement.
Partial Molal Volume of Some Alkali Halides in Water—Acetamide Mixtures
Authors: Woldan Marian 
Published: July 2012

AbstractDensities of solutions of NaCl, Nal, KCI, KBr, and Csl in mixtures of acetamide + water have been measured at 313.15 K using the magnetic float densimeter. The apparent molal volumes of the electrolytes calculated from the experimental data were extrapolated to infinite dilution by means of the Masson equation. The ionic partial molal volumes of the ions have been estimated. The dependence of the partial molal volumes, the ionic partial molal volumes, and the derived transfer functions of the investigated electrolytes (ions) from water to water‐acetamide mixtures on the solvent composition are discussed.
Recent results in laser biomedicine and some prospects of the future
Authors: Letokhov V. S. 
Published: July 2012

AbstractReport will discuss the following problems:

Molecular mechanism of low‐intensity laser therapy
Mechanism and characteristics of laser ablation of biotissue
Femtosecond Laser Mass‐Spectrometry of Biomolecules on Surface and Future Applications for Laser Photoion Microscopy
Photodynamic therapy of age‐related macular degeneration and atherosclerosis
Authors: Ben‐Hur E. , Miller B. , Miller H. , Rosenthal I. 
Published: July 2012

AbstractIn photodynamic therapy, a photosensitizing dye restrictively localized to certain sites in the biological milieu, is activated by visible light to selectively destroy the stained structures. Although primarily investigated for necroting malignant tumors, this approach suggests also potential in treating other pathological conditions such as age‐related macular degeneration and atherosclerosis. Until recently, hematoporphyring derivative was practically the only dye investigated for photodynamic therapy. The use of phthalocyanine dyes is being explored as a superior alternative photosensitizer for treatment of these diseases.
Resonance enhanced multiphoton ionization of biological molecules
Authors: Beavis R. C. , Lindner J. , Grotemeyer J. , Schlag E. W. 
Published: July 2012

AbstractSome applications of the powerful novel method of laser desorption combined with multiphoton ionization are shown. The mass spectra of several bio‐organic molecules are presented and their intrinsic features upon the multiphoton interaction are discussed. In every case, at low laser powers the molecular ion of the investigated sample is detected, while at higher laser powers structure dependent fragmentations can be observed.
Lasers and flashlamps in research on the mechanism of muscle contraction
Authors: Rapp G. , Poole K. J. V. , Maeda Y. , Ellis‐Davies G. C. R. , Kaplan J. H. , McCray J. , Goody R. S. 
Published: July 2012

AbstractHigh intensity pulsed light sources are currently being used in two major applications in muscle research. The first of these involves rapid photolytic release of metabolites, e.g. adenosine triphosphate or calcium ions, from inert, photosensitive precursors. This allows rapid kinetic experiments in muscle fibres which would otherwise be impossible because of the long diffusion times even of small molecules into the lattice of thick and thin filaments. Examples of the use of lasers and flash lamps for this purpose will be given, with particular emphasis on dynamic structural investigations using synchrotron radiation as a high intensity X‐ray source for monitoring structural changes by low angle diffraction. The second application involves the use of solid state lasers to produce powerful light pulses in the infrared region to achieve temperature jumps in muscle fibres. This, in conjunction with the use of synchrotron radiation, allows the kinetics of interesting structural transitions in muscle fibres to be studied.
Structures of Some Derivatives of Chloral. An X‐Ray and NQR Study
Authors: Hashimoto Masao , Nakamura Yasushige , Adachi Masahiro , Hamada Kensaku , Mano Koichi 
Published: July 2012

AbstractCrystal structures of the stable and a metastable phases of 2,4‐bis(trichloromethyl)‐benzo‐1,3‐dioxine‐6‐carboxylic acid (TMB‐COOH) and 2,4‐bis(trichloromethyl)‐benzo‐1,3‐dioxine‐6‐amine (TMB‐NH2) were determined at room temperature. Crystal data are as follows; TMB‐COOH (stable): monoclinic, space group C52h‐P21/n, a = (1052.6 ± 0.2) pm, b = (2582.2 ± 0.4) pm, c = 598.7 ± 0.3) pm, β = 99.86° ± 0.02°, R = 0.053; TMB‐COOH (metastable): monoclinic,space group C52h‐P21/c, a = (577.5 ± 0.5) pm, b = (2087.2 ± 1.1) pm, c = (1318.6 ± 0.7) pm, β = 91.98° ± 0.06°, R = 0.098; TMB‐NH2: orthorhombic, space group C92v‐Pna21, a = (2539.0 ± 0.2) pm, b = (1005.1 ± 0.1) pm, c = (566.7 ± 0.1) pm, R = 0.049. Disorder of hydrogen atom in the OH ··· O hydrogen bond system was found for the cyclic dimers of TMB‐COOH in both phases. Judging from the molecular structures determined, chloral hydrate and 4‐substituted phenols seem to react in a stereospecific way to give a single conformer found in these crystals. The 35Cl NQR spectra of TMB‐COOH, TMB‐NH2 and related compounds were measured in the range 77 ≦ T/K ≦ 400. The temperature dependence of the NQR spectra showed that the potential barrier hindering the reorientation of the group is considerably different for the two nonequivalent CCl3 groups in a molecule. Atom‐atom potential calculations based on the crystal data showed that the difference is of intermolecular nature. The NQR frequencies calculated from the orbital populations obtained by the CNDO/2 MO method are consistent with the observed one.
A control method based on modal transformation for biped robots to climb unknown steps
Authors: Shimmyo Shuhei , Nakazato Miki , Mikami Kei , Sato Tomoya , Sakaino Sho , Ohnishi Kouhei 
Published: July 2012

AbstractThis paper proposes a control method based on a modal transformation for biped robots to climb unknown steps. The method is able to control the foot position of the biped robot and the ground reaction force acting in the vertical direction when the biped robot climbs unknown steps in a double support phase. The effectiveness of the proposed method is confirmed by the results of simulations and experiments. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(3): 59‐69, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21265
Efficient sampling of protein conformational space using fast loop building and batch minimization on highly parallel computers
Authors: Tyka Michael D. , Jung Kenneth , Baker David 
Published: July 2012

AbstractAll‐atom sampling is a critical and compute‐intensive end stage to protein structural modeling. Because of the vast size and extreme ruggedness of conformational space, even close to the native structure, the high‐resolution sampling problem is almost as difficult as predicting the rough fold of a protein. Here, we present a combination of new algorithms that considerably speed up the exploration of very rugged conformational landscapes and are capable of finding heretofore hidden low‐energy states. The algorithm is based on a hierarchical workflow and can be parallelized on supercomputers with up to 128,000 compute cores with near perfect efficiency. Such scaling behavior is notable, as with Moore's law continuing only in the number of cores per chip, parallelizability is a critical property of new algorithms. Using the enhanced sampling power, we have uncovered previously invisible deficiencies in the Rosetta force field and created an extensive decoy training set for optimizing and testing force fields. © 2012 Wiley Periodicals, Inc.
A robust inner–outer hierarchically semi‐separable preconditioner
Authors: Xia J. 
Published: July 2012

SUMMARYIn this paper, an inner–outer preconditioner for symmetric positive definite matrices based on hierarchically semi‐separable (HSS) matrix representation is presented. A sequence of new HSS algorithms are developed, including some ULV‐type HSS methods and triangular HSS methods. During the construction of this preconditioner, off‐diagonal blocks are compressed in parallel, and an approximate HSS form is used as the outer HSS representation. In the meantime, the internal dense diagonal blocks are approximately factorized into HSS Cholesky factors. Such inner factorizations are guaranteed to exist for any approximation accuracy. The inner–outer preconditioner combines the advantages of both direct HSS and triangular HSS methods, and are both scalable and robust. Systematic complexity analysis and discussions of the errors are presented. Various tests on some practical numerical problems are used to demonstrate the efficiency and robustness. In particular, the effectiveness of the preconditioner in iterative solutions has been shown for some ill‐conditioned problems. This work also gives a practical way of developing inner–outer preconditioners using direct rank structured factorizations (other than iterative methods). Copyright © 2012 John Wiley & Sons, Ltd.
Effect of growth media on cell envelope composition and nitrile hydratase stability in Rhodococcus rhodochrous strain DAP 96253
Authors: Tucker Trudy-Ann , Crow Sidney A , Pierce George E 
Published: July 2012

Abstract
Rhodococcus is an important industrial microorganism that possesses diverse metabolic capabilities; it also has a cell envelope, composed of an outer layer of mycolic acids and glycolipids. Selected Rhodococcus species when induced are capable of transforming nitriles to the corresponding amide by the enzyme nitrile hydratase (NHase), and subsequently to the corresponding acid via an amidase. This nitrile biochemistry has generated interest in using the rhodococci as biocatalysts. It was hypothesized that altering sugars in the growth medium might impact cell envelope components and have effects on NHase. When the primary carbon source in growth media was changed from glucose to fructose, maltose, or maltodextrin, the NHase activity increased. Cells grown in the presence of maltose and maltodextrin showed the highest activities against propionitrile, 197 and 202 units/mg cdw, respectively. Stability of NHase was also affected as cells grown in the presence of maltose and maltodextrin retained more NHase activity at 55 °C (45 and 23 %, respectively) than cells grown in the presence of glucose or fructose (19 and 10 %, respectively). Supplementation of trehalose in the growth media resulted in increased NHase stability at 55 °C, as cells grown in the presence of glucose retained 40 % NHase activity as opposed to 19 % without the presence of trehalose. Changes in cell envelope components, such mycolic acids and glycolipids, were evaluated by high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC), respectively. Changing sugars and the addition of inducing components for NHase, such as cobalt and urea in growth media, resulted in changes in mycolic acid profiles. Mycolic acid content increased 5 times when cobalt and urea were added to media with glucose. Glycolipids levels were also affected by the changes in sugars and addition of inducing components. This research demonstrates that carbohydrate selection impacts NHase activity and stability. Cell envelope components such as mycolic acids are also influenced by sugars and inducers such as cobalt and urea. This is information that can be useful when implementing rhodococcal catalysts in industrial applications.
Modeling the speech community: Configuration and variable types in the Mexican Spanish setting
Authors: Ana Otto Santa , Parodi Claudia 
Published: July 2012

ABSTRACTThis article proposes a comprehensive model of the SPEECH COMMUNITY in sociolinguistics that reworks Labov's model, which has been criticized as being restrictive. Fieldork in non-metropolitan Mexico demonstrates the utility of our model, which can be applied across both urban and non-urban domains. It is compatible with the Milroys' central mechanism for the description of individual speech usage and group cohesion or susceptibility to change in terms of the social network. Based on linguistic variable types, this model has a hierarchy of four nested fields (speech community configurations) into which each individual is placed, according to his/her demonstrated recognition of the social evaluation associated with the variables. At the most local configuration, speakers demonstrate no knowledge of generally stigmatized variables; in the second, speakers register an awareness of stigmatized variables; in the third, an awareness of stigmatized and regional variables; and in the fourth, speakers model standard variants over regional ones. This model classifies the kinds of sociolinguistic variables that are pertinent in this social setting and also provides a structured manner for dealing with dialect contact dynamics. (Speech community, social network, Spanish, Mexico, dialect, diffusion, variables.)
Native woodlands of the Inner Hebrides
Authors: Ball M. E. 
Published: July 2012

SynopsisWoodland is native throughout the Inner Hebrides at low elevations wherever exposure and soil conditions permit. Although mostly destroyed in the distant past, sufficient remnants remain to characterise Hebridean woods and provide a basis for their study and conservation. Surveys have revealed that the types represented are those dominated by wych-elm, ash, oak, birch, hazel, alder and sallows. All but the smallest and most exposed islands have remnant woodlands but the widest variety of types and the most demanding species occur on the larger islands of Mull and Skye. The woodland flora is rich in oceanic species and poor in continental, boreal plants characteristic of the mainland pine–birch woodlands, although Scots pine probably once occurred sparsely in the primaeval woodland.The most powerful factor influencing between-site variation in the woodland flora is geology, with wychelm, ash and hazel associated with soils on Durness limestone, Mezozoic rocks and basalts, and oak and birch characteristic of the Torridonian sandstones, acid Moine rocks, Lewisian gneiss and granites. There is little active conservation; the most pressing need is protection from grazing and fire to ensure long-term survival.