bluuebunny/crossref_metadata_2025 huggingface dataset:
23Na MAS‐NMR and 1H MAS‐NMR Studies in the Hydro‐Sodalite System
Authors: Buhl J.‐Ch. , Engelhardt G. , Felsche J. , Luger S. , Foerster H.
Published: March 2014

The basic (x = 2, n = 4), (x = 2, n = 0) and the non‐basic (x = 0, n = 8), (x = 0, n = 0) species of the hydrosodalite system Na6+x[AlSiO4]6(OH)x · nH2O have been studied by 23Na MAS‐NMR and 1H MAS‐NMR techniques at 297 K. The spectra are discussed in terms of structural data, which are provided by X‐ray and neutron diffraction experiments on hydro‐sodalite phases of identical compositions. The 1H MAS‐NMR spectrum of the non‐basic phase Na6[AlSiO4]6 · 8H2O confirms the recent neutron diffraction data. The chemical shift of 4.2 ppm correlates to regular water molecules in the sodalite cage, which show hydrogen bonding to the framework oxygens. The 1H MAS‐NMR double peak spectrum of the basic hydro‐sodalite species Na8[AlSiO4]6(OH)2 · 4H2O correlates with the structural OH groupings (3.4 ppm) and with one proton per ß‐cage (—1.0 ppm) showing a significant magnetic shielding effect. The large diamagnetic shift (—6.5 ppm) of the resonance signal in the 1H MAS‐NMR spectrum of the hydroxy‐sodalite Na8[AlSiO4]6(OH)2 indicates substantial change in the chemical bond of the hydrogen atom upon dehydration of the tetrahydrate Na8[AlSiO4]6(OH)2 · 4H2O at 775 K. — The phases of the non‐basic hydro‐sodalites show 23Na chemical shifts of approximately —8 and —9 ppm for the octahedrally coordinated sodium atoms in the octahydrate (n = 8) and in the anhydrous (n = 0) sodalite, respectively. — The 23Na chemical shifts of the basic sodalites range from —0.6 to —5.6 ppm, and the species reveal considerable quadrupolar interactions. At least two types of sodium ions are registered in basic hydro‐sodalite (n = 4) in accordance with structure analysis.
Classical and Quantum Mechanical Features in the Photodissociation of Small Polyatomic Molecules
Authors: Schinke R. , Engel V. , Hennig S. , Weide K. , Untch A.
Published: March 2014

We review some recent progress in theoretical studies of photodissociation of polyatomic molecules. The first part features the inelastic reflection principle which is a straight forward extension of the well known one‐dimensional (elastic) reflection principle. It allows to interprete final rotational‐vibrational state distributions of the fragments in terms of the wavefunction of the parent molecule and the intermolecular interaction in the exit channel (final state interaction). It is discussed for two model systems and the photodissociation of H2O2. In the second part of the article we discuss diffuse structures in the total absorption spectra of H2O (first and second band) and CH3ONO. We present exact quantum mechanical calcualtions using ab initio potential energy surfaces. In each case we compare directly with available experimental data.
Acetylene: Isomerization and Dissociation
Authors: Chen Yongqin , Jonas David M. , Hamilton Charles E. , Green Peter G. , Kinsey J. L. , Field R. W.
Published: March 2014

The Stimulated Emission Pumping (SEP) spectrum at 15600 cm−1 above the HCCH X1σ+g zero point level contains features diagnostic of isomerization to vinylidene. It also illustrates a powerful new way, spectral cross‐correlation, for extracting dynamical information from high resolution spectra. SEP spectra of the same X̃‐state energy region, from two different intermediate levels (33 vs. 2142), are cross‐correlated. The correlation index is expected and found to be insignificant, except for isolated energy regions where a vinylidene basis state promotes acetylene mode mixing. The energy width of the correlated region is a direct measure of the distribution of vinylidene character into predominantly acetylene eigenstates. SEP spectra of HCCD provide additional information about the acetylene‐vinylidene isomerization process. The HCC‐H dissociation energy is poorly known but crucial to kinetic models for hydrocarbon combustion. The presence of a low lying excited state in HCC and HCC+ complicates the interpretation of dissociation and ionization threshold experiments. Zeeman Anticrossing Spectroscopy provides an opportunity to detect the onset of predissociation in a single rovibronic level of the HCCH Ã state by inducing anticrossings with levels of the T1 and T2 surfaces (all three isomers of each, cis‐HCCH, trans‐HCCH, and vinylidene) and, indirectly, with high vibrational levels of the X̃ state. We have detected one predissociative anticrossing in HCCH Ã υ3 = 4, J = Ka = 1.
Infrared Laser Induced Fluorescence Studies of State Mixing in Ground Electronic State Molecules
Authors: Minton T. K. , McDonald J. D.
Published: March 2014

During the past several years, infrared laser induced fluorescence experiments in our laboratory have been used to probe the nature of state mixing in the C—H stretch fundamental frequency region of various organic molecules. Both total and dispersed IR fluorescence have been collected from molecules, cooled and isolated in a molecular beam, after excitation with an infrared optical parametric oscillator. Measurements of the dilution factor, which is inversely related to the number of coupled states, as a function of molecule, vibrational band, and average J value excited have yielded the result that the extent of state mixing is J dependent and scales linearly with J. The extensive body of data on the dilution factors has also provided an empirical correlation between the dilution factors and the density of rovibrational states. This relationship shows that about 70 rovibrational states/cm−1 of proper J and symmetry are necessary to ensure substantial state mixing, regardless of molecular structure. The relative energy contents of various vibrational modes after laser excitation can also be determined. A statistical mixing model has been refined to the point of being able to predict dilution factors and their J dependence as well as the relative energy contents of the modes which are involved in the makeup of the mixed excited states. This model assumes equal coupling between all the zeroth order rovibrational states that have the correct energy, symmetry, and J to couple to a given optically active state. The only adjustable parameter in this model is the average energy width over which the character of the zeroth order optically active excited state is spread, which is determined to be ˜0.05 cm−1.
Is there a Signature of the Chaoticity of the Asssociated Classical System in the Spectrum of a Quantum System?
Authors: Lombardi M. , Labastie P. , Bordas M. C. , Broyer M.
Published: March 2014

The cause of the appearance of chaos in classical dynamics is the disappearance of first integrals of the movement which restrict the motion of the configuration point in phase space. This enables the system to wander in increasing parts of the phase space. The direct consequence in quantum mechanics is the disappearance of quantum numbers and of the corresponding selection rules. We will discuss two consequences of this disappearance of selection rules.

(1) Level repulsion enabled by breakdown of selection rules. While most papers deal with nearest neighbour spacing distribution, we will show that the most relevant consequence on the dynamical behavior is intermediate and long range correlations between level positions. We will display the correspondence between dynamical evolution in classical, semiclassical limit, and full quantum mechanical versions of a given system.

(2) Periodic simplification of spectra due to periodic reestablishment of approximate quantum numbers and associated selection rules, and its counterpart in chaotic or regular parts of classical phase space, in the case of molecular Rydberg states.
Dynamics of Molecular Photoionization Studied by Zero Kinetics Energy Photoelectron Spectroscopy
Authors: Habenicht W. , Baumann R. , Müller‐Dethlefs K. , Schlag E. W.
Published: March 2014

We use high‐resolution two‐colour zero kinetic energy photoelectron spectroscopy (ZEKE‐PES) with full ionic rotational state selection to study photoionization processes of NO from selected rovibronic levels of the A2Σ+ (v = 0, NA) state. The angular momentum transfer molecule → ion seems to depend on the transition chosen for the selection of the intermediate rotational level in the NO A state.
Tyrosine Fluorescence Energy Transfer as a Probe for Interactions of Proteins with DNA
Authors: Schwarzwald Ralf , Greulich Karl Otto
Published: March 2014

The fluorescence decay of the aromatic amino acid tyrosine, as well as of symmetric tripeptides is monoexponential, the fluorescence lifetimes can be understood on the basis of a simple empirical equation for first order rate constants of energy transfer from tyrosine to neighboring amino acids. Fluorescence energy transfer from tyrosine to DNA in protein‐DNA complexes can be used to elucidate the role of Tyr‐DNA interaction in the formation of inverted DNA, a postulated new type of DNA structure and gives information on differences of the role of the positively charged amino acids lysine and arginine in electrostatic protein‐DNA interaction.
Dynamic NMR Study of the Interference between Cyclic Proton Exchange, Selfassociation and Hindered Rotation of Diphenylformamidine in Tetrahydrofuran
Authors: Meschede Ludger , Gerritzen Detlef , Limbach Hans‐Heinrich
Published: March 2014

The 90 MHz1H NMR spectra of15N,15N′‐dipentadeuterophenylformamidine (DPFA), a nitrogen analogue of formic acid, dissolved in tetrahydrofuran‐d8(THF) have been measured as a function of concentration, deuterium fraction in the1H‐15N sites, and of temperature. The spectra show characteristic changes, from which thermodynamic and kinetic information on hindered rotation, hydrogen bond association and proton exchange of DPFA in THF are obtained by NMR lineshape analysis. DPFA forms two conformers A and B in THF, to which s‐trans and s‐cis structures have been assigned. At low concentrations both DPFA conformers are located in a hydrogen bond to the solvent molecules. However, as a result of the different structure, only A is able to selfassociate to any observable extent. This effect leads to concentration dependent A/B populations. Higher selfassociates or mixed AB associates are not observed. Whereas B is not able to exchange protons, A is subject to a very fast proton transfer. By measuring proton lifetimes as a function of concentration and of the deuterium fraction in the labile proton sites, it was established that two protons are transferred in every exchange process. Thermodynamic data of the association process obtained by the analysis of the chemical shifts, of the A/B populations and the proton lifetimes as a function of concentration agreed very well. These results are evidence that A forms only selfassociated hydrogen bonded dimers with a cyclic structure in which the double proton transfer takes place. The observation of a kinetic HH/HD isotope effect of 20 at 178 K establishes this transfer as the rate limiting step of the overall proton exchange. Rate constants of the double proton transfer in the cyclic dimer were obtained as a function of temperature from which an activation energy of about 19 kJ mol−1was obtained. In addition, the rates of interconversion between the two conformers were determined as a function of temperature. Details of the reaction mechanism and differences to the related carboxylic acids are discussed. Thus, it is shown that dynamic NMR spectroscopy can be a useful tool for elucidating elementary steps of complex reaction networks.
Quenching of CHF [Ã1 A″ (0,0 ≦ υ′2 ≦ 5,0)] after Single Vibronic Level Excitation by the Diatomic Molecules H2, O2 and CO
Authors: Dornhöfer G. , Hack W.
Published: March 2014

The elementary deactivation processes of CHF (Ã, υ′2) by H2(X1Σ+g), O2(X3Σ−g), and CO(X1Σ+) were studied in a quasistatic photolysis chamber. Determination of time and spectrally resolved laser‐induced fluorescence of CHF (Ã1 A″, υ′2) in single vibronic excited levels (SVL) (0 ≦ υ′2 ≦ 5) was carried out in the gas phase at room temperature. CHF [X̃1 A′ (0,0,0)] was generated in the fluorescence cell by multiphoton dissociation (MPD) of CH2F2.

The overall CHF (Ã, υ′2)‐depletion rate constants:

magnified image

A significant increase of the rate constants for higher vibronic states was observed. The contribution of vibration deactivation to the overall depletion of the initially excited state was found to be small (≦ 10%), with approximately the same importance of collision‐induced vibrational quantum change of Δυ′2 = 1 and Δυ′2 = 2 respectively. The reaction mechanisms are discussed.
A Chemical Approach to the Prediction of Thermophysical Properties of Associating Compounds
Authors: Ksiązczak Andrzej , Anderko Andrzej
Published: March 2014

A method is presented for predicting gas‐ and liquid‐phase association constants from vapor pressure data using the homomorph concept. The gas‐phase dimerization parameters for alcohols, phenols, amines and carboxylic acids are compared with those obtained from p‐V‐T, thermal conductivity, heat capacity and spectroscopic data. The predicted association enthalpies are in agreement with the results of dilute solution calorimetric measurements. A generalization of the method in terms of topological parameters characterizing molecular structure is proposed. The correlations of association constants with topological parameters allow to reproduce second virial coefficients or vapor pressures on the basis of the structural formula of an associating compound.
Steady Flow Viscosity and Rigidity of Colloidal Spheres in Deionized Suspensions
Authors: Okubo T.
Published: March 2014

Steady‐flow viscosities of colloidal spheres, i.e., colloidal silica (8–45 nm in diameter) and monodisperse polystyrene latices (diam. 85 to 780 nm), are measured in deionized suspensions and in the presence of a small amount of NaCl. The plots of shear stress (S) of the crystal‐like structure of the colloids against shear rate (q) show the following features: (1) at very small values of q (smaller than 0.1 s−1), S increases very sharply with increasing q. The S – q curve is S‐shaped, and the rigidity (G) of the colloidal crystal is evaluated from the plots of S against qt/2 (shear strain), where t is time. The G‐values are between 20 and 3000 Pa, which are consistent with those reported hitherto, and increase as the sphere's concentration increases. (2) The sharp increase in S ceases above the critical q value, from which the yield stress of the crystal‐like structure is evaluated to be between 0.1 to 2 Pa. (3) The log (viscosity, η) vs. log q plots shows non‐Newtonian flows: η increases as q decreases and then η reachs a constant value. Furthermore, log η begins to increase linearly as log q decreases with a slope of −1, which supports the crystal‐like nature of the suspensions.
Coherence in Disordered Condensed Matter. II: Size of Coherent Structures in Condensed Systems owing to Luminescent Transitions, and Detection of D‐Fluctuations
Authors: Chatzidimitriou‐Dreismann C. A. , Brändas E. J.
Published: March 2014

A connection between complex scaling method (CSM), the Prigogine theory of star‐unitary transformations and the luminescence spectroscopic experiment is presented. CSM predicts the existence of coherent (or: dissipative) structures appearing spontaneously in amorphous matter like liquids, due to the thermal motion. A typical spatial size of these coherent structures is estimated. The connection with measurements of D‐fluctuations is shortly discussed.
Factors Determining the Rate of Dissolution of Metal Oxides in Acidic Aqueous Solutions
Authors: Valverde Nilo
Published: March 2014

Empirical rules governing the dissolution rates of oxides of the transition metals in acidic solutions containing redox systems are exemplified by the dissolution of CoO. Deviations from these rules shown during the dissolution of NiO (and partly of CuO) are discussed. The presence of organic complexing agents in the solution enhances in general the rate of dissolution of metal oxides. In the case of the iron oxides, induction periods of slow dissolution have been observed. An interpretation of these induction periods is based on a particular formation mechanism of metal chelates. The combined action of redox potential and complexing agent in the solution leads to a decrease of the dissolution rates, due possibly to a blocking of crystal surface sites by constituents of the redox couple and the complexing agent.
Cylindrical Poisson‐Boltzmann Equation for Polyelectrolyte Systems and Counterion Condensation Theory
Authors: Cametti C. , Di Biasio A.
Published: March 2014

The numerical solution of the full non‐linear Poisson‐Boltzmann equation for cylindrical polyelectrolyte systems in presence of simple added salts is employed to illustrate the counterion condensation effect occurring at high values of the charge density parameter. The computational results indicate that the main features of counterion condensation remain approximately unchanged upon the adding of simple electrolytes. These results stress the relevance of the Manning condensation theory in the understanding colligative and transport properties of highly charged polyelectrolytes solutions.
Vapour Pressures and Ionic Activity Coefficients in the System KNO3 + H2O from Dilute Solutions to Fused Salts at 425 K, 452 K, and 492 K
Authors: Barry J. C. , Richter J. , Stich E.
Published: March 2014

Vapour pressure measurements at elevated temperatures in the system KNO3 + H2O over the entire solubility range are reported. The mean ionic salt activities in the pure fused salt standard state and the excess functions of the molar free enthalpy of mixing were computed. Here the activity model of van Laar and one suggested by Pitzer were adopted for analytical treatment of data. Our results match satisfactorily with data from other sources in the lower temperature region. The tendency in this system towards a weakly positive deviation from ideal mixing behaviour is confirmed in the explored temperature range. – Pitzer's formalism is well‐suited for a concentration independent representation of water activity coefficients in this system if the ion size parameter ϱ is allowed to assume larger values than recommended by Pitzer. A rise of ϱ with the temperature seems necessary in view of an optimal representation of the activity data.
Electrochemical Engineering in Disperse Multiphase Systems
Authors: Kreysa G.
Published: March 2014

Electrochemical multiphase systems of industrial importance may be divided into dispersed three‐dimensional electrodes, gas evolving electrodes, conversion of gaseous reactants and electrochemical extraction systems. The engineering fundamentals of all these types developed by several groups during the recent years will be summarized. Additionally new electrochemical techniques for studying non‐electrochemical unit operations like absorption and extraction will be introduced.
Reductive Cleavage of the Co,C‐Bond of [(Methoxycarbonyl)methyl]cobalamin
Authors: Tinembart Olivier , Walder Lorenz , Scheffold Rolf
Published: March 2014

The synthesis and characterization of [(methoxycarbonyl)methyl]‐cobalamin 1d is reported. Cyclic voltammetry of 1d in DMSO at a Hg‐electrode shows two irreversible cathodic waves corresponding to the reduction of the base‐off and base‐on forms of 1d. At sweep rates lower than 0.5 V/s, only reduction of the base‐off form is observed (Ep (off) = −0.954 V vs SCE at 0.1 V/s). At sweep rates faster than 10 V/s, reduction of the base‐on form prevails (Ep (on) = −1.422 V vs SCE at 10 V/s). The thermodynamic and kinetic parameters of the base‐off/base‐on equilibrium of 1d in DMSO are estimated. Two electrons are involved in the reduction of 1d in 0.1 M CH3COOH/DMF. In the absence of a proton source, one‐electron reduction predominates. B12s is a sufficiently strong reducing agent to induce reductive decomposition of 1d.
Elektrochemische Grenzstromsensoren für Partialdruckmessungen
Authors: Jahnke H. , Moro B. , Dietz H. , Beyer B.
Published: March 2014

Potentiometrie sensors as the λ‐sensor deliver a sufficiently high signal only in a narrow region near the point of equivalence. The reason is the logarithmic dependence of the voltage on the partial pressure of the gas to be measured. For measurements outside of this range limiting current sensors are suitable, their current signal being proportional to the gas concentration. The limiting current can be regulated either by a solid membrane or by gas diffusion, for example in narrow pores. – Depending upon the gas to be converted, the limiting current sensors can be operated cathodically or anodically. All electrochemically convertible gases can be measured in principle. By selection of proper electrode materials and potentials it is possible within limits to gain selective signals. – Sensors with solid as well with liquid electrolytes are dealt with.
Stability of Photoelectrodes Controlled by Electronic Factors: Layered Chalcogenides of Group IV b
Authors: Jaegermann W. , Pettenkofer C.
Published: March 2014

The reactivity of group IV B semiconducting layered compounds (ZrSe2 and ZrS2) has been investigated with surface science techniques (XPS, UPS, and LEED). The surface has been analyzed after chemical and electrochemical oxidation. Type and concentration of oxidation products have been determined. An increased reactivity compared to group VI B layered chalcogenides is found. The semiconductor/electrolyte interface is simulated by adsorption of halogens onto UHV cleaved (0001) surfaces. A light induced reaction of the interface is observed in contrast to the ideal Schottky type behaviour found for MoSe2 for which surface photovoltages have been obtained. The differences in reactivity are discussed in relation to the different electronic structure of the chalcogenides (valence band edges of metal d‐character for MoSe2 and chalcogenide p‐character for ZrSe2 and ZrS2).
An Electrochemical Study on Titanium‐ and Titanium Oxide Electrodes with Oscillating Quartz Crystals
Authors: Müller A. , Wicker M. , Schumacher R. , Schindler R. N.
Published: March 2014

The electrochemical passivation of titanium was investigated by using oscillating quartz crystals as electrode supports. In addition complex plane impedance diagrams and potentiodynamic data were registrated. The results show, that only a fraction of the anodic charge passed through the cell leads to oxide formation. It could be demonstrated, that surface reactions to form hydroxilated surface sites give rise to significant frequency changes. The shifts were attributed to coupling/decoupling of the hydroxilated surface to/from the electrolyte bulk.
Synthesis of 5,10,15,20‐Tetrakisphenylporphins on a Carbon Support for the Cathodic Reduction of Oxygen in Fuel Cells
Authors: Kirschenmann M. , Wöhrle D. , Vielstich W.
Published: March 2014

Several substituted Fe‐ and Co‐containing tetraphenylporphins 1 were loaded on carbon either by adsorption from acetone or by in situ synthesis on the carbon support. The porphin/carbon combinations were pyrolyzed at 800°C. The electrocatalytic activities in the reduction of dioxygen were investigated in alkaline (KOH) and acid (H2SO4) solutions using porous Teflon‐bonded carbon electrodes impregnated with the catalysts. At 700 mV high current densities of 75 mA/cm2 in acid solution and up to 90 mA/cm2 in alkaline solution were obtained.
Cyclovoltammetric Characterization of Carbon Black Slurry Electrodes
Authors: Heydecke Gabriele , Beck F.
Published: March 2014

Slurry electrodes in 1 M H3PO4, made from carbon blacks with a specific surface ranging from 28 to 1475 m2 g−1, were studied by cyclovoltammetry (5 mV s−1) at potentials between −0.1 V and +2.3 V vs. SHE. A large anodic peak and a small cathodic one is found, with an extreme peak separation (1.5 V) and with a charge ratio of 3:1 to 5:1. Charge transfer at the feeder is hindered by insulating surface layers on the carbon black. Part of the anodic peak is due to the irreversible oxidation of the solid. The initial curves are governed by the large capacity of the system. – This slurry electrode differs widely from that made with metal powders or hard graphite. The particles strongly adhere to the feeder and build up a porous system. The exchange with the dispersed particles is poor. In spite of this, the curves are reproducible, they reflect the specific surface and it is possible to recognize features with respect to the anodic oxidation of carbon black.
Herstellung eines Berberin‐Sensors und seine Eigenschaften
Authors: Aubeck R. , Hampp N. , Bräuchle C.
Published: March 2014

The fabrication and the properties of a berberine‐sensitive electrode are reported. It is based on a highly lipophilic ion pair from berberine and tetraphenylborate (BerbTPB). PVC liquid membranes containing 10% BerbTPB were characterized by use of a newly developed transducer (BIOBRID‐module). The detection limit of the berberine‐sensor is 10−8 mol/l, the linear response range is observed from 10−7 to 10−5 mol/l. Interference of inorganic cations like Na+, K+, Li+, Mg2+ and Ca2+ is negligible (Apotij < 10−4). The logarithmic cross selectivity coefficients for some structural related alkaloids show that BerbTPB is a suitable selective ion pair for the manufacture of a liquid membrane based potentiometric berberine sensor (Coralyne 10−0.6, Papaverine 10−2.1, Atropine 10−4.2).
Electrochemical Determination of the Small Hydrogen Decomposition Pressures in HxMoO3
Authors: Schwitzgebel G. , Adams St.
Published: March 2014

In analogy to the O2 solid electrolyte probe a proton conducting membrane (Nafion®) was used in an electrochemical cell for the determination of the small H2 decomposition pressures of the bronze phases of MoO3 (HxMoO3): 4.8 · 10−15 Pa for 0 < x < 0.23, 6.3 · 10−9 Pa for 0.40 < x < 0.85 and 1.1 · 10−2 Pa for 1.04 < x < 1.55. – Potential control at the gas electrode is even possible during small current flows, so that diffusion coefficients (D) could be obtained by analysing the potentiostatic oxidation of single phased samples: (2.5 ± 1.0) · 10−8 cm2 s−1 for x = 0.23, (2.4 ± 1.6) · 10−6 cm2 s−1 for x = 0.85 and (1.6 ± 0.9) · 10−8 cm2 s−1 for x = 1.55.
Forces and Torques Acting on Two Parallel Dielectric Cylinders in a Periodic Transverse Field. A.
Authors: Schlögl Reinhard W.
Published: March 2014

Starting from the solution of the potential equation in bipolar coordinates the forces and torques acting on the cylinders are calculated. In contrast to two earlier papers, a periodic field and dissipative media are anticipated. Cylinders of different radii and material are assumed in general. Whereas the forces on the cylinders are equal in magnitude but of opposite sign, the torques are in general different. If only one of the cylinders has a vanishing loss angle a “uni‐lateral” torque exists. In the case of identical cylinders the expressions for the interactions are essentially simplified, the torques being identical in magnitude and sign. – There is little hope to obtain closed solutions of the analogous problem in 3 dimensions (spheres, ellipsoides, etc.) that is of high practical interest. However, the information gained from the most simple “two dimensional” example allows for a valuable qualitative generalization.
An embedded system course using JavaME and android
Authors: Rodriguez‐Sanchez Maria Cristina , Hernandez‐Tamames Juan A. , Borromeo Susana
Published: March 2014

This paper describes the objectives and contents of a cost‐effective curriculum for embedded system course in our university. The main aim of the course is learning to solve a real problem by developing a real system. The students learn skills to adapt this system to new scenarios. The system consists of a wireless module, a microcontroller and an application for smartphones to control lights by wireless communications. In order to motivate students, JavaME and Android, the important technologies for today's smartphones were chosen. As a result of the course, following the Bologna guidelines, the students worked cooperatively, like in a real scenario. Each group member worked in a complementary manner by analyzing the division of tasks for each student. We followed project‐based methodology has provided an incremental learning to students. According to results, students responded to the course survey that they are knowledgeable on how embedded systems work after taking the course. © 2014 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:294–303, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21599
Calotropin: A Cardenolide from Calotropis gigantea that Inhibits Wnt Signaling by Increasing Casein Kinase 1α in Colon Cancer Cells
Authors: Park Hyun Young , Toume Kazufumi , Arai Midori A. , Sadhu Samir K. , Ahmed Firoj , Ishibashi Masami
Published: March 2014

Wnt signaling plays key roles in embryonic development and various human diseases. Activity‐guided testing to isolate Wnt signaling inhibitors from the methanol extract of Calotropis gigantea (Asclepiadaceae) exudutes identified six Wnt inhibitory cardenolides (1–6), of which 1, 3, 5, and 6 exhibited potent TCF/β‐catenin inhibitory activities (IC50 0.7–3.6 nM). Calotropin (1) inhibited Wnt signaling by decreasing both nuclear and cytosolic β‐catenin in a dose‐dependent manner, and promoted degradation of β‐catenin by increasing the phosphorylation of β‐catenin at Ser45 through casein kinase 1α (CK1α). Moreover, 1 significantly increased CK1α protein and mRNA levels. The results suggest that 1 inhibits the Wnt signaling pathway by increasing CK1α protein levels. To the best of our knowledge, calotropin is the first small molecule to increase CK1α levels.
Imatinib‐induced gastric antral vascular ectasia in a patient with chronic myeloid leukemia
Authors: Alshehry Nawal F. , Kortan Paul , Lipton Jeffrey H.
Published: March 2014

Key Clinical Message

Gastric antral vascular ectasia (GAVE) has been reported very rarely in imatinib‐treated gastrointestinal stromal tumor (GIST) and scleroderma/pulmonary hypertension patients. We present the first report of a case of GAVE in a chronic myeloid leukemia (CML) patient after treatment with imatinib. This diagnosis should be considered in CML patients with upper gastrointestinal symptoms and anemia.
An Efficient Oxygen Activation Route for Improved Ammonia Oxidation through an Oxygen‐Permeable Catalytic Membrane
Authors: Cao Zhengwen , Jiang Heqing , Luo Huixia , Baumann Stefan , Meulenberg Wilhelm A. , Voss Hartwig , Caro Jürgen
Published: March 2014

Upon using a reactant/oxygen mixture as co‐feed in partial oxidation, adsorbed surface molecular oxygen species can cause low selectivity. We propose a concept different from the conventional co‐feed partial oxidation process in packed‐bed reactors. In this new configuration, the activation of oxygen is separated from the catalytic oxidation by using an oxygen‐permeable membrane to suppress the formation of nonselective surface molecular oxygen species. A continuous flux of lattice oxygen through the membrane allows highly selective partial oxidation. In the oxidation of ammonia to NO, the NO selectivity was improved from 77 to 95 % if a La0.6Sr0.4Co0.2Fe0.8O3–δ oxygen‐permeable catalytically active membrane was used at 850 °C instead of a co‐feed fixed bed reactor.
(1‐Butyl‐4‐methyl‐pyridinium)[Cu(SCN)2]: A Coordination Polymer and Ionic Liquid
Authors: Eike T. Spielberg  , Edengeiser Eugen , Mallick Bert , Havenith Martina , Mudring Anja‐Verena
Published: March 2014

The compound (C4C1py)[Cu(SCN)2], (C4C1py=1‐Butyl‐4‐methyl‐pyridinium), which can be obtained from CuSCN and the ionic liquid (C4C1py)(SCN), turns out to be a new organic–inorganic hybrid material as it qualifies both, as a coordination polymer and an ionic liquid. It features linked [Cu(SCN)2]− units, in which the thiocyanates bridge the copper ions in a μ1,3‐fashion. The resulting one‐dimensional chains run along the a axis, separated by the C4C1py counterions. Powder X‐ray diffraction not only confirms the single‐crystal X‐ray structure solution but proves the reformation of the coordination polymer from an isotropic melt. However, the materials shows a complex thermal behavior often encountered for ionic liquids such as a strong tendency to form a supercooled melt. At a relatively high cooling rate, glass formation is observed. When heating this melt in differential scanning calorimetry (DSC) and temperature‐dependent polarizing optical microscopy (POM), investigations reveal the existence of a less thermodynamically stable crystalline polymorph. Raman measurements conducted at 10 and 100 °C point towards the formation of polyanionic chain fragments in the melt. Solid‐state UV/Vis spectroscopy shows a broad absorption band around 18 870 cm−1 (530 nm) and another strong one below 20 000 cm−1 (<500 nm). The latter is attributed to the d(CuI)→π*(SCN)‐MLCT (metal‐to‐ligand charge transfer) transition within the coordination polymer yielding an energy gap of 2.4 eV. At room temperature and upon irradiation with UV light, the material shows a weak fluorescence band at 15 870 cm−1 (630 nm) with a quantum efficiency of 0.90(2) % and a lifetime of 131(2) ns. Upon lowering the temperature, the luminescence intensity strongly increases. Simultaneously, the band around 450 nm in the excitation spectrum decreases.
Calcite Microneedle Arrays Produced by Inorganic Ion‐Assisted Anisotropic Dissolution of Bulk Calcite Crystal
Authors: Long Xia , Meng Ruijie , Wu Weike , Ma Yurong , Yang Dong , Qi Limin
Published: March 2014

Besides studies on the mineralization process, research on the demineralization of minerals provides another way to understand the crystallization mechanism of biominerals and fabricate crystals with complicated morphologies. The formation of ordered arrays of c‐axis‐oriented calcite microneedles with a tri‐symmetric structure and lengths of more than 20 μm was realized on a large scale for the first time through anisotropic dissolution of calcite substrates in undersaturated aqueous solution in the presence of ammonium salts. The lengths and the aspect ratios of the calcite microneedles can be tuned by simply changing the concentrations of the ammonium salts and the dissolution time. The shape of the transverse cross sections of the calcite microneedles obtained in the presence of NH4Cl and NH4Ac is almost regularly triangular. The tri‐symmetric transverse cross‐section geometry of the calcite microneedles could be attributed to the tri‐symmetric feature of rhombohedral calcite atomic structures, the synergetic interactions between electrostatic interaction of ammonium ions and dangling surface carbonate groups, and the ion incorporation of halide ions.
Formation of a Ligand‐Assisted Complex of Two RNA Hairpin Loops
Authors: Hong Changfeng , Otabe Takahiro , Matsumoto Saki , Dohno Chikara , Murata Asako , Hagihara Masaki , Nakatani Kazuhiko
Published: March 2014

The hairpin structure is one of the most common secondary structures in RNA and holds a central position in the stream of RNA folding from a non‐structured RNA to structurally complex and functional ribonucleoproteins. Since the RNA secondary structure is strongly correlated to the function and can be modulated by the binding of small molecules, we have investigated the modulation of RNA folding by a ligand‐assisted formation of loop–loop complexes of two RNA hairpin loops. With a ligand (NCT6), designed based on the ligand binding to the G–G mismatches in double‐stranded DNA, we successfully demonstrated the formation of both inter‐ and intra‐molecular NCT6‐assisted complex of two RNA hairpin loops. NCT6 selectively bound to the two hairpin loops containing (CGG)3 in the loop region. Native polyacrylamide gel electrophoresis analysis of two doubly‐labeled RNA hairpin loops clearly showed the formation of intermolecular NCT6‐assisted loop–loop complex. Förster resonance energy‐transfer studies of RNA constructs containing two hairpin loops, in which each hairpin was labeled with Alexa488 and Cy3 fluorophores, showed the conformational change of the RNA constructs upon binding of NCT6. These experimental data showed that NCT6 simultaneously bound to two hairpin RNAs at the loop region, and can induce the conformational change of the RNA molecule. These data strongly support that NCT6 functions as molecular glue for two hairpin RNAs.
Rhodium(III)‐Catalyzed Selective ortho‐Olefinations of N‐Acyl and N‐Aroyl Sulfoximines by CH Bond Activation
Authors: Parthasarathy Kanniyappan , Bolm Carsten
Published: March 2014

Two new rhodium‐catalyzed oxidative couplings between sulfoximine derivatives and alkenes by regioselective CH activation, affording ortho‐olefinated (Heck‐type) products, are reported. A synthetic application of the ortho‐alkenylated products into the corresponding cyclic derivatives has been demonstrated, and a mechanistic rational for the rhodium catalysis is presented.
A Single‐Step Reaction for Silicon and Germanium Nanorods
Authors: Lu Xiaotang , Korgel Brian A.
Published: March 2014

A single‐step reaction has been developed for colloidal quantum‐size silicon (Si) and germanium (Ge) nanorods. The nanorods are formed by solution–liquid–solid (SLS) growth from tin (Sn) seed particles prepared by in situ reduction of a molecular tin(II) complex by trisilane, the reactant for Si nanorod growth. Using the same procedure, Ge nanorods can be grown by including a diphenyl germane reactant. The nanorod length could be adjusted from several nanometers to more than a micrometer without significant increase of diameter by manipulating reactant concentrations.
Five National Cancer Institute–designated cancer centers' data collection on racial/ethnic minority participation in therapeutic trials
Authors: Hawk Ernest T. , Habermann Elizabeth B. , Ford Jean G. , Wenzel Jennifer A. , Brahmer Julie R. , Chen Moon S. , Jones Lovell A. , Hurd Thelma C. , Rogers Lisa M. , Nguyen Lynne H. , Ahluwalia Jasjit S. , Fouad Mona , Vickers Selwyn M.
Published: March 2014

BACKGROUND

To ensure that National Institutes of Health‐funded research is relevant to the population's needs, specific emphasis on proportional representation of minority/sex groups into National Cancer Institute (NCI) cancer centers' clinical research programs is reported to the NCI.

METHODS

EMPaCT investigators at 5 regionally diverse comprehensive cancer centers compared data reported to the NCI for their most recent Cancer Center Support Grant competitive renewal to assess and compare the centers' catchment area designations, data definitions, data elements, collection processes, reporting, and performance regarding proportional representation of race/ethnicity and sex subsets.

RESULTS

Cancer centers' catchment area definitions differed widely in terms of their cancer patient versus general population specificity, levels of specificity, and geographic coverage. Racial/ethnic categories were similar, yet were defined differently, across institutions. Patients' socioeconomic status and insurance status were inconsistently captured across the 5 centers.

CONCLUSIONS

Catchment area definitions and the collection of patient‐level demographic factors varied widely across the 5 comprehensive cancer centers. This challenged the assessment of success by cancer centers in accruing representative populations into the cancer research enterprise. Accrual of minorities was less than desired for at least 1 racial/ethnic subcategory at 4 of the 5 centers. Institutions should clearly and consistently declare their primary catchment area and the rationale and should report how race/ethnicity and sex are defined, determined, collected, and reported. More standardized, frequent, consistent collection, reporting, and review of these data are recommended, as is a commitment to collecting socioeconomic data, given that socioeconomic status is a primary driver of cancer disparities in the United States. Cancer 2014;120(7 suppl):1113–21. © 2014 American Cancer Society.
The Patient Protection and Affordable Care Act: Is it good or bad for oncology?
Authors: Kantarjian Hagop M. , Steensma David P. , Light Donald W.
Published: March 2014

The Patient Protection and Affordable Care Act (ACA) has many flaws that need to be addressed, but it is better than what was. Oncologists should advocate for the ACA and work on improving it.
In Situ Growth of Noble‐Metal Nanoparticles on Cu2O Nanocubes for Surface‐Enhanced Raman Scattering Detection
Authors: Wang Jie , Cui Fangling , Chu Sibin , Jin Xiaoquan , Pu Jun , Wang Zhenghua
Published: March 2014

Gold and silver nanoparticles with a narrow size distribution were grown in situ on the surfaces of Cu2O nanocubes through a wet‐chemical reduction route. The Cu2O nanocubes serve as both the substrate and reducing agent. The as‐prepared Cu2OAu and Cu2OAg nanocomposites still retain the cubic morphology of the original Cu2O nanocubes. The Cu2OAu and Cu2OAg nanocomposites can serve as effective surface‐enhanced Raman scattering (SERS) substrates. Rhodamine 6G as a Raman probe was applied to determine the effects of the SERS substrates; the results show that Cu2OAg nanocomposites have higher sensitivity and good reproducibility. Furthermore, the Cu2OAg substrate was also applied to detect plasticizers, such as dimethyl phthalate and dibutyl phthalate, and shows potential applications in the area of food safety screening.
An exact feature selection algorithm based on rough set theory
Authors: Rezvan Mohammad Taghi , Hamadani Ali Zeinal , Hejazi Seyed Reza
Published: March 2014

Feature reduction based on rough set theory is an effective feature selection method in pattern recognition applications. Finding a minimal subset of the original features is inherent in rough set approach to feature selection. As feature reduction is a Nondeterministic Polynomial‐time‐hard problem, it is necessary to develop fast optimal or near‐optimal feature selection algorithms. This article aims to propose an exact feature selection algorithm in rough set that is efficient in terms of computation time. The proposed algorithm begins the examination of a solution tree by a breadth‐first strategy. The pruned nodes are held in a version of the trie data structure. Based on the monotonic property of dependency degree, all subsets of the pruned nodes cannot be optimal solutions. Thus, by detecting these subsets in trie, it is not necessary to calculate their dependency degree. The search on the tree continues until the optimal solution is found. This algorithm is improved by selecting an initial search level determined by the hill‐climbing method instead of searching the tree from the level below the root. The length of the minimal reduct and the size of data set can influence which starting search level is more efficient. The experimental results using some of the standard UCI data sets, demonstrate that the proposed algorithm is effective and efficient for data sets with more than 30 features. © 2014 Wiley Periodicals, Inc. Complexity 20: 50–62, 2015
Two sexes, one body: intra‐ and intersex covariation of gamete phenotypes in simultaneous hermaphrodites
Authors: Monro Keyne , Marshall Dustin J.
Published: March 2014

By harboring male and female functions in the same genome and expressing them in every individual, simultaneous hermaphrodites may incur sexual conflict unless both sex functions can evolve phenotypic optima independently of each other. The first step toward understanding their capacity to do so lies in understanding whether sex functions are phenotypically correlated within individuals, but remarkably few data address this issue. We tested the potential for intra‐ and intersex covariation of gamete phenotypes to mediate sexual conflict in broadcast‐spawning hermaphrodites (the ascidians Ciona intestinalis and Pyura praeputialis), for which sex‐specific selection acts predominantly on sperm–egg interactions in the water column. In both species, gamete phenotypes covaried within and across sex functions, implying that selection may be unable to target them independently because its direct effects on male gametes translate into correlated effects on female gametes and vice versa. This alone does not preclude the evolution of a different phenotypic optimum for each sex function, but imposes the more restrictive requirement that selection – which ultimately sorts among whole individuals, not sex functions – aligns with the direction in which gamete phenotypes covary at this level.
Trifluoromethylthiolation of Diazo Compounds through Copper Carbene Migratory Insertion
Authors: Wang Xi , Zhou Yujing , Ji Guojing , Wu Guojiao , Li Ming , Zhang Yan , Wang Jianbo
Published: March 2014

A strategy to introduce the SCF3 group through the CuI‐promoted reaction of diazo compounds with the nucleophilic AgSCF3 trifluoromethylthiolation reagent was developed. Various diazo compounds were smoothly converted under mild conditions to form the C(sp3)–SCF3 bond. Mechanistically, migratory insertion of SCF3‐bearing Cu carbene intermediates is involved in this transformation.
Nanohybrid Materials Consisting of Poly[(3‐aminobenzoic acid)‐co‐(3‐aminobenzenesulfonic acid)‐co‐aniline] and Multiwalled Carbon Nanotubes for Immobilization of Redox Active Cytochrome c
Authors: Tanne Johannes , Dietzel Birgit , Scheller F. W. , Bier Frank
Published: March 2014

The development of a new surface architecture for the efficient direct electron transfer of positively charged redox proteins is presented. For this reason different kinds of polyaniline terpolymers consisting of aminobenzoic acid (AB), aminobenzenesulfonic acid (ABS) and aniline (A) with different monomer ratios were synthesized. The P(AB‐ABS‐A) were grafted to the surface of multiwalled carbon nanotubes (MWCNTs). FTIR measurements prove the covalent binding to the carboxylic groups of the MWCNTs while conductivity tests show an increase in the conductivity of the nanohybrid in comparison to the polymers. The [MWCNT‐P(AB‐ABS‐A)] nanohybrids were used for the immobilization of redox active cytochrome c (cyt.c). The positively charged protein can electrostatically interact with the negatively charged nanohybrid. Cyclic voltammetry (CV) shows an increase in the protein loading on [MWCNT‐P(AB‐ABS‐A)] coupled to cysteamine modified gold electrodes in comparison to non‐grafted MWCNTs. A further increase in the sulfonation degree of P(AB‐ABS‐A) leads to an enhanced current output of the modified electrodes. The redox activity of the polymer decreases after the immobilization of the cyt.c on the nanohybrid. For the first time polymers covalently grafted to the surface of MWCNTs are used in a biosensor.
A Partially Linear Approach to Modeling the Dynamics of Spot and Futures Prices
Authors: Gaul Jürgen , Theissen Erik
Published: March 2014

This paper considers the dynamics of spot and futures prices in the presence of arbitrage. A partially linear error correction model is proposed where the adjustment coefficient is allowed to depend nonlinearly on the lagged price difference. The model is estimated using data on the DAX index and the DAX futures contract. We find that the adjustment is indeed nonlinear. The linear alternative is rejected. The speed of price adjustment is increasing almost monotonically with the magnitude of the price difference. © 2014 Wiley Periodicals, Inc. Jrl Fut Mark 35:371–384, 2015
Four Major Trends in Utility Customer Communications
Authors:   iFactor Consulting
Published: March 2014

New tools and strategies for communicating with utility customers continue to be a prime topic of discussion for utility companies, but what is behind the urgency of this topic? From the fallout following recent superstorms and other natural disasters to the influx of consumer technologies and a growing focus on energy‐efficiency programs, utilities are challenged to provide customers with more information through more channels than ever before.
Electric Regulation: Has Retail Choice Delivered for Natural Gas Residential Customers?
Authors: Bowden Nicholas S.
Published: March 2014

The nationwide participation of residential customers in natural gas retail choice programs has grown from less than 0.5 percent of total US residential customers in 1997 to over 10 percent in 2012. Seventy percent of the 2012 total comes from three states: Georgia, New York, and Ohio. Add Illinois, Maryland, Michigan, New Jersey, and Pennsylvania, and the eight states constitute nearly 95 percent of the total residential retail choice market participation.