bluuebunny/crossref_metadata_2025 huggingface dataset:
Schottky ultraviolet photodiode using a ZnO hydrothermally grown single crystal substrate
Authors: Endo Haruyuki , Sugibuchi Mayo , Takahashi Kousuke , Goto Shunsuke , Sugimura Shigeaki , Hane Kazuhiro , Kashiwaba Yasube
Published: March 2007

A Schottky ultraviolet photodiode using a (0001) ZnO single crystal grown by the hydrothermal growth method is reported. The photodiode consisted of a semitransparent Pt film for the Schottky electrode and an Al thin film for the Ohmic electrode. The photodiode had polarity dependences on current-voltage characteristics and on responsivity. In the case of the Schottky electrode on the zinc surface, the responsivity was 0.185A∕W at a wavelength of 365nm. On the other hand, the responsivity was 0.09A∕W for an oxygen surface. The results are attributed to the polarity dependences of surface chemical reactivity and the surface state density on ZnO surfaces.
Zeeman splitting in ballistic GaInAs∕InP split-gate quantum point contacts
Authors: Schäpers Th. , Guzenko V. A. , Hardtdegen H.
Published: March 2007

The Zeeman splitting in ballistic GaxIn1−xAs∕InP split-gate point contacts was investigated. The measurements were performed in a magnetic field perpendicular to the plane of the two-dimensional electron gas. The Zeeman energy splitting between the one-dimensional subbands was determined by measuring the differential conductance as a function of the dc source-drain voltage across the point contact. The g factor of approximately 4.0 extracted from measurements at various magnetic fields agrees well to the value obtained by other methods for this type of heterostructure.
Interface dominated biferroic La0.6Sr0.4MnO3∕0.7Pb(Mg1∕3Nb2∕3)O3–0.3PbTiO3 epitaxial superlattices
Authors: Roy Chaudhuri Ayan , Ranjith R. , Krupanidhi S. B. , Mangalam R. V. K. , Sundaresan A.
Published: March 2007

Superlattices composed of ferromagnetic La0.6Sr0.4MnO3 and ferroelectric 0.7Pb(Mg1∕3Nb2∕3)O3–0.3(PbTiO3) layers were fabricated on (100) LaAlO3 substrates by pulsed laser deposition technique. The ferromagnetic and frequency independent ferroelectric hysteresis characteristics established the biferroic nature of the superlattices. Influence of magnetic field was observed in tuning the P-E characteristics of the superlattices. A similar effect was observed on application of a high dc electric field to the samples. The nature of the observed ferroelectric properties and their modulation by applied magnetic and electric fields were thus discussed in connection to the ferroelectric/ferromagnetic interfaces.
Carrier capture dynamics of InAs∕GaAs quantum dots
Authors: Piwonski T. , O’Driscoll I. , Houlihan J. , Huyet G. , Manning R. J. , Uskov A. V.
Published: March 2007

Carrier dynamics of a 1.3μm InAs∕GaAs quantum dot amplifier is studied using heterodyne pump-probe spectroscopy. Measurements of the recovery times versus injection current reveal a power law behavior predicted by a quantum dot rate equation model. These results indicate that Auger processes dominate the carrier dynamics.
Resonant tunneling diode with spin polarized injector
Authors: Slobodskyy A. , Gould C. , Slobodskyy T. , Schmidt G. , Molenkamp L. W. , Sánchez D.
Published: March 2007

The authors investigate the current-voltage characteristics of a II-VI semiconductor resonant tunneling diode coupled to a diluted magnetic semiconductor injector. As a result of an external magnetic field, a giant Zeeman splitting develops in the injector, which modifies the band structure of the device, strongly affecting the transport properties. They find a large increase in peak amplitude accompanied by a shift of the resonance to higher voltages with increasing fields. They discuss a model which shows that the effect arises from a combination of three-dimensional incident distribution, giant Zeeman spin splitting, and broad resonance linewidth.
Impacts of a polycrystalline-silicon buffer layer on the performance and reliability of strained n-channel metal-oxide-semiconductor field-effect transistors with SiN capping
Authors: Lu Ching-Sen , Lin Horng-Chih , Huang Jian-Ming , Lee Yao-Jen
Published: March 2007

Characteristics of n-channel metal-oxide-semiconductor field-effect transistors with SiN capping were investigated in this work. Although the SiN capping could dramatically enhance the carrier mobility and thus the device drive current, the resistance to hot-carrier degradation is compromised as well, owing to the large amount of hydrogen contained in the SiN layer which may diffuse into the channel region during the process. To eliminate this shortcoming, the insertion of an ultrathin (10nm) polycrystalline-silicon buffer layer between the gate and the SiN capping was proposed and demonstrated to restore the hot-carrier reliability of the devices without compromising the current enhancement due to the SiN capping.
Microstructure analysis of c-axis oriented aluminum nitride thin films by high-resolution transmission electron microscopy
Authors: Yao Z. Q. , Ye Q. , Li Y. Q. , Zou Y. S. , Zhang W. J. , Lee S. T.
Published: March 2007

The microstructure, in particular, the surface and interface regions, of the c-axis orientated AlN films deposited on Si (100) substrates was studied. The films showed an evolutionary columnar growth process. In contrast to the previous reports, high-resolution transmission electron microscopy revealed that the AlN films grew directly on substrates without an amorphous interlayer, despite the large lattice mismatch between AlN and Si. The occurrence of misoriented and/or amorphous top layer suggested a subsurface growth/relaxation process of the AlN films by reactive sputtering.
Single Schottky-barrier photodiode with interdigitated-finger geometry: Application to diamond
Authors: Liao Meiyong , Koide Yasuo , Alvarez Jose
Published: March 2007

The authors propose a single Schottky-barrier photodiode (SPD) with interdigitated Ohmic and Schottky contacts. A homoepitaxial diamond layer with low boron concentration has been utilized as an example for the fabrication of solar-blind deep-ultraviolet detector. This device structure enables the operations in both photoconductive mode with large photocurrent gain and depletion mode with fast response speed. The photosensitivity and spectral response of such kind of device are greatly improved when compared with a conventional SPD with semitransparent dotted Schottky contact. The present device structure can be extended to other semiconductor photodetectors.
Three-dimensional carbon nanowall structures
Authors: Chuang Alfred T. H. , Robertson John , Boskovic Bojan O. , Koziol Krzysztof K. K.
Published: March 2007

The authors report the growth of carbon nanowalls in freestanding, three-dimensional aggregates by microwave plasma-enhanced chemical vapor deposition. Carbon nanowalls extrude from plasma sites into three-dimensional space. The growth is catalyst-free and not limited by nucleating surfaces. The growth mechanism is discussed and compared with similar carbon nanomaterials. High surface area of as-grown carbon nanowalls indicates a potential for electrochemical applications. Field emission measurements show a low field turn-on and long-term stability. The results establish a scalable production method and possible applications using field emission or high surface area.
Effects of molecular oxygen and ozone on polythiophene-based thin-film transistors
Authors: Chabinyc Michael L. , Street Robert A. , Northrup John E.
Published: March 2007

The effects of exposure of polymeric thin-film transistors (TFTs) to the ambient atmosphere, oxygen, and ozone were investigated. The off-state current increased and the threshold voltage became more positive for TFTs made with several thiophene-based polymers when exposed to the ambient. Exposure to purified air did not change the characteristics of TFTs. Exposure to ozone caused similar changes as exposure to the ambient. Density functional calculations showed that ozone forms a complex with polythiophene, that is, a shallow acceptor. These results suggest that ozone in the ambient can cause changes in electrical characteristics of polythiophene-based TFTs rather than oxygen.
Experimental investigation of the lattice and electronic temperatures in Ga0.47In0.53As∕Al0.62Ga0.38As1−xSbx quantum-cascade lasers
Authors: Vitiello Miriam S. , Scamarcio Gaetano , Spagnolo Vincenzo , Lops Antonia , Yang Quankui , Manz Christian , Wagner Joachim
Published: March 2007

The authors extracted the thermal resistance (RL=9.6K∕W) and the electrical power dependence of the electronic temperature (Re=12.5K∕W) of Ga0.47In0.53As∕Al0.62Ga0.38As1−xSbx quantum-cascade lasers (QCLs) operating at 4.9μm, in the lattice temperature range of 60–90K. The low electron-lattice coupling constant α=10.4Kcm2∕kA can be related to the beneficial effect of the high conduction band offset, peculiar to the GaInAs∕AlGaAsSb material system, on the electron leakage. The authors found an active region cross-plane thermal conductivity value k⊥=1.8±0.1W∕(Km), which is approximately three times larger than that measured in QCLs with GaInAs∕AlInAs heterostructures.
Thermodynamic Properties of Ideal Gas Nitro and Nitrate Compounds
Authors: Burcat Alexander
Published: March 2007

The ideal gas thermodynamic properties of 27 organic nitro and nitrate organic compounds and two of their radicals are presented. Most of these compounds are high explosives (TNT, RDX, HMX, PETN, NPN, and NG), while others serve as propellants or specialty fuels (such as nitromethane). The thermodynamic properties were calculated using fundamental molecular data. The molecular data were gathered from the literature or calculated for this purpose. The enthalpy of formation of gaseous 1-nitropentane was estimated to be −164.431 kJ mol−1 (−39.3±0.5 kcal mol−1); that of 1-nitrohexane to be −185.351 kJ mol−1 (−44.3±0.7 kcal mol−1) for the ideal gas and −241.835 kJ mol−1 (−57.8±0.7 kcal mol−1) for the liquid. All values refer to 298.15 K.
Evaluation of Calculated and Measured Electron Inelastic Mean Free Paths Near Solid Surfaces
Authors: Powell C. J. , Jablonski A.
Published: March 2007

An analysis is given of the consistency of calculated and measured electron inelastic mean free paths (IMFPs) near solid surfaces for electron energies between 50 and 104 eV, the energy range of relevance for surface analysis by Auger electron spectroscopy and x-ray photoelectron spectroscopy. This evaluation is based on IMFPs calculated from experimental optical data and on IMFPs measured by elastic-peak electron spectroscopy (EPES). We describe the methods used for the calculations and measurements, and we identify the various sources of uncertainty. Most of our evaluation is based on IMFPs for seven elemental solids (Al, Si, Ni, Cu, Ge, Ag, and Au) for which there were at least two sources of IMFP calculations and at least two sources of IMFP measurements for each solid. Our comparison of the calculated IMFPs showed a high degree of consistency for Al, Ni, Cu, Ag, and Au. The comparison of measured IMFPs showed greater scatter than for the calculated IMFPs, but reasonable consistency was found for the measured IMFPs of Cu and Ag. The measured IMFPs for four elements (Ni, Cu, Ag, and Au) showed good consistency with the corresponding calculated IMFPs. It is recommended that IMFPs for these four elements (determined from fits of a simple analytic expression to the calculated IMFPs for each element) be used as reference values in future EPES experiments. More limited comparisons have been made of calculated and measured IMFPs for four additional elements (Fe, Mo, W, and Pt) and of calculated IMFPs for six compounds (Al2O3, SiO2, KCl, poly(butene-1-sulfone), polyethylene, and polystyrene).
Electron Interactions With Cl2
Authors: Christophorou L. G. , Olthoff J. K.
Published: March 2007

Low-energy electron interactions with the Cl2 molecule are reviewed. Information is synthesized and assessed on the cross sections for total electron scattering, total rotational excitation, total elastic electron scattering, momentum transfer, total vibrational excitation, electronic excitation, total dissociation into neutrals, total ionization, total electron attachment, and ion-pair formation. Similar data on the density-reduced ionization, density-reduced electron attachment, density-reduced effective ionization, electron transport coefficients, and electron attachment rate constant are also synthesized and critically evaluated. Cross sections are suggested for total electron scattering, total elastic electron scattering, total ionization, dissociation into neutrals, electron attachment, and ion-pair formation. A cross section is derived for the total vibrational excitation cross section via low-lying negative ion resonances. Data are suggested for the coefficients for electron attachment, ionization, and effective ionization, and for the rate constant for electron attachment. While progress has been made regarding our knowledge on electron–chlorine interactions at low energies (<100 eV), there is still a need for: (i) improvement in the uncertainties of all suggested cross sections; (ii) measurement of the cross sections for momentum transfer, vibrational excitation, electronic excitation, and dissociative ionization; and (iii) accurate measurement of the electron transport coefficients in pure Cl2 and in mixtures with rare gases. Also provided in this paper is pertinent information on the primary Cl2 discharge byproducts Cl2+, Cl2−, Cl, Cl−, and Cl+.
A New Equation of State for Argon Covering the Fluid Region for Temperatures From the Melting Line to 700 K at Pressures up to 1000 MPa
Authors: Tegeler Ch. , Span Roland , Wagner Wolfgang
Published: March 2007

This work reviews the available data on thermodynamic properties of argon and presents a new equation of state in the form of a fundamental equation explicit in the Helmholtz energy. The functional form of the residual part of the Helmholtz energy was developed by using state-of-the-art linear optimization strategies and a new nonlinear regression analysis. The new equation of state contains 41 coefficients, which were fitted to selected data of the following properties: (a) thermal properties of the single phase (pρT) and (b) of the liquid–vapor saturation curve (ps, ρ′, ρ″) including the Maxwell criterion, (c) speed of sound w, isochoric heat capacity cv, second and third thermal virial coefficients B and C and second acoustic virial coefficient βa. For the density, the estimated uncertainty of the new equation of state is less than ±0.02% for pressures up to 12 MPa and temperatures up to 340 K with the exception of the critical region and less than ±0.03% for pressures up to 30 MPa and temperatures between 235 and 520 K. In the region with densities up to half the critical density and for temperatures between 90 and 450 K the estimated uncertainty of calculated speeds of sound is in general less than ±0.02%. The new formulation shows reasonable extrapolation behavior up to very high pressures and temperatures. Independent equations for the vapor pressure, for the pressure on the sublimation and melting curve and for the saturated liquid and saturated vapor densities are also included. Tables for the thermodynamic properties of argon from 84 to 700 K for pressures up to 1000 MPa are given.
Phase Behavior and Miscibility in Binary Blends Containing Polymers and Copolymers of Styrene, of 2,6-Dimethyl-1,4-Phenylene Oxide, and of Their Derivatives
Authors: Vuković Radivoje , Bogdanić Grozdana , Karasz Frank E. , MacKnight William J.
Published: March 2007

This article presents a comprehensive and systematic survey of miscibility in binary mixtures of polymers and copolymers based on styrene, on 2,6-dimethyl-1,4-phenylene oxide, and on their derivatives. Certain other systems based on methacrylate, acrylonitrile, and maleic anhydride-containing polymers are also included to complete the analysis. Experimental and theoretical studies of miscibility and phase behavior of homopolymer/homopolymer, homopolymer/copolymer, and copolymer/copolymer blends are analyzed. A mean field model is employed to correlate and predict miscibility in new systems. This model is also used to account for the different phenomena governing miscibility/immiscibility behavior, with special reference to the influence of the chemical structure of the polymers. Tables containing experimental data and related details are included for 127 polymer/polymer systems; these tables also contain summaries of the binary phase behavior. Calculated segmental interaction parameters, together with the relevant references and recommended values, are also tabulated.
IUPAC-NIST Solubility Data Series 67. Halogenated Ethanes and Ethenes with Water
Authors: Horvath Ari L. , Getzen Forrest W. , Maczynska Z.
Published: March 2007

This volume covers the solubilities of halogenated ethanes and ethenes with water, heavy water, seawater, and aqueous electrolyte solutions. All data were critically examined for their reliability and best value estimates were selected on the basis of such evaluations. Referenced works are presented in the standard IUPAC-NIST Solubility Data Series format. Reported and best value data are presented in tabular form and, where justified, data correlation equations and graphical illustrations are provided. Throughout the volume, SI conventions have been employed as the customary units. The importance of these data arises from the fact that halogenated ethanes and ethenes have commercial uses as industrial chemicals, propellants, solvents, and the like. In such applications, often from spillage, leakage, or mishandling, they contact water and are exposed to the atmosphere. The data are essential for concentration estimates for the halogenated ethanes and ethenes in drinking and ground water, foodstuffs, human tissue, marine organisms, and the atmosphere. The halogenated aliphatics are of particular interest to health scientists, engineers, environmentalists, and atmospheric chemists in that they represent a class of chemical materials which has many significant industrial applications. However, at the same time, these substances have been shown, in some cases, to be carcinogenic and also to be especially damaging to the earth’s atmospheric composition through their chemical reactivity which results in atmospheric ozone depletion. The high ozone depletion potentials of this class of chemical substances emphasizes the importance of having available complete, accurate, and reliable data for mutual solubilities with water. The availability of such data is essential for estimates of halogenated hydrocarbon levels in both natural waters and aqueous industrial liquids which result from industrial fabrication, industrial waste removal processes, and the like. The data also provide significant solubility values for studies concerning the health of human and other biological systems.
Phase Diagrams and Thermodynamic Properties of Binary Systems of Drugs
Authors: Sangster James
Published: March 2007

The phase diagram data of 60 binary systems of drugs were evaluated with the aid of a computer-coupled phase diagram/thermodynamic analysis. Data for this analysis were obtained by an exhaustive literature search (110 references). Among the results of this analysis are the excess Gibbs energy of liquid and solid solution phases, and the thermodynamic properties of intermediate compounds. For each system a phase diagram was calculated; such calculated diagrams are thermodynamically consistent and are offered as the best constructions which can be deduced from available data.
Thermodynamics of Enzyme-Catalyzed Reactions: Part 6—1999 Update
Authors: Goldberg Robert N.
Published: March 2007

This review serves to update previously published evaluations of equilibrium constants and enthalpy changes for enzyme-catalyzed reactions. For each reaction the following information is given: the reference for the data; the reaction studied; the name of the enzyme used and its Enzyme Commission number; the method of measurement; the conditions of measurement [temperature, pH, ionic strength, and the buffer(s) and cofactor(s) used]; the data and an evaluation of it; and, sometimes, commentary on the data and on any corrections which have been applied to it or any calculations for which the data have been used. The data from 96 references have been examined and evaluated. Chemical Abstract Service registry numbers are given for the substances involved in these various reactions. There is also a cross reference between the substances and the Enzyme Commission numbers of the enzymes used to catalyze the reactions in which the substances participate.
Electron Interactions With Plasma Processing Gases: An Update for CF4, CHF3, C2F6, and C3F8
Authors: Christophorou L. G. , Olthoff J. K.
Published: March 2007

An update of electron–collision cross sections and electron transport parameters is presented for CF4, CHF3, C2F6, and C3F8.
Evaluated Chemical Kinetics Data for Reactions of N(2D), N(2P), and N2(A 3Σu+) in the Gas Phase
Authors: Herron John T.
Published: March 2007

Chemical kinetics data for the gas phase reactions of the first two electronically excited states of atomic nitrogen: N(2D) and N(2P), and of the first excited state of molecular nitrogen N2(A 3Σu+) are compiled and evaluated. The experimental data for 127 reactions are summarized, the experimental method and year of publication given, a recommended value given for the rate constant for each reaction at 298 K, and where possible, its temperature dependence. The reaction mechanisms are discussed within the limits of the available quantitative product yield data. The literature has been covered through early 1999. There are 94 references.
Thermodynamic Properties of Import to Environmental Processes and Remediation. II. Previous Thermodynamic Property Values for Nickel and Some of its Compounds
Authors: Archer Donald G.
Published: March 2007

The sources of previous thermodynamic property values are detailed for nickel and some compounds of nickel that might be expected as derived from anthropogenic introduction of nickel into the environment or are required for calculation of thermodynamic properties of nickel-containing systems. Included are descriptions of the sources of information and the methodology used to obtain the values for these compounds reported in the NBS series of publications loosely and collectively referred to as the NBS Thermodynamics Tables.
Estimating Solid–Liquid Phase Change Enthalpies and Entropies
Authors: Chickos James S. , Acree William E. , Liebman Joel F.
Published: March 2007

A group additivity method based on molecular structure is described that can be used to estimate solid–liquid total phase change entropy (Δ0TfusStpce) and enthalpy (Δ0TfusHtpce) of organic molecules. The estimation of these phase changes is described and numerous examples are provided to guide the user in evaluating these properties for a broad range of organic structures. A total of 1858 compounds were used in deriving the group values and these values are tested on a database of 260 additional compounds. The absolute average and relative errors between experimental and calculated values for these 1858 compounds are 9.9 J⋅mol−1⋅K−1 and 3.52 kJ⋅mol−1, and 0.154 and 0.17 for Δ0TfusStpce and Δ0TfusHtpce, respectively. For the 260 test compounds, standard deviations of ±13.0 J⋅mol−1⋅K−1(Δ0TfusStpce) and ±4.88 kJ mol−1(Δ0TfusHtpce) between experimental and calculated values were obtained. Estimations are provided for both databases. Fusion enthalpies for some additional compounds not included in the statistics are also included in the tabulation.
Revised Thermochemical Properties of Phosphinidene (PH), Phosphine (PH3), Phosphorus Nitride (PN), and Magnesium Phosphate (Mg3P2O8)
Authors: Lodders Katharina
Published: March 2007

Revised thermochemical tables for phosphinidene (PH), phosphine (PH3), phosphorus nitride (PN), and magnesium orthophosphate (Mg3P2O8) are computed. These computations were done because the P reference state was not adjusted to the white P reference state and/or because the tables of these compounds are printed erroneously in the 4th edition of the NIST-JANAF Thermochemical Tables.
Binding Energies in Atomic Negative Ions: III
Authors: Andersen T. , Haugen H. K. , Hotop H.
Published: March 2007

This article updates a 14 yr old review on this subject [J. Phys. Chem. Ref. Data 14, 731 (1985)]. A survey of the electron affinity determinations for the elements up to Z=94 is presented, and based upon these data, a set of recommended electron affinities is established. New developments in the experimental methods which yield accurate electron binding energies are described. Fine structure splittings and excited state energies of negative ions as well as lifetimes of metastable states are given. Progress in theoretical calculations of atomic electron affinities is documented by comparison with reliable experimental data.
Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry, Organic Species: Supplement VII
Authors: Atkinson R. , Baulch D. L. , Cox R. A. , Hampson R. F. , Kerr J. A. , Rossi M. J. , Troe J.
Published: March 2007

This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photochemistry of gas-phase chemical reactions of neutral species involved in atmospheric chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997)]. The present evaluation is limited to the organic family of atmospherically important reactions. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 171 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations which model atmospheric chemistry. A table summarizing the preferred rate data is provided, together with an Appendix listing the available values of enthalpies of formation of the reactant and product species.
CODATA Recommended Values of the Fundamental Physical Constants: 1998
Authors: Mohr Peter J. , Taylor Barry N.
Published: March 2007

This paper gives the 1998 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. Further, it describes in detail the adjustment of the values of the subset of constants on which the complete 1998 set of recommended values is based. The 1998 set replaces its immediate predecessor recommended by CODATA in 1986. The new adjustment, which takes into account all of the data available through 31 December 1998, is a significant advance over its 1986 counterpart. The standard uncertainties (i.e., estimated standard deviations) of the new recommended values are in most cases about 1/5 to 1/12 and in some cases 1/160 times the standard uncertainties of the corresponding 1986 value. Moreover, in almost all cases the absolute values of the differences between the 1998 values and the corresponding 1986 values are less than twice the standard uncertainties of the 1986 values. The new set of recommended values is available on the World Wide Web at physics.nist.gov/constants.
IUPAC-NIST Solubility Data Series 70. Solubility of Gases in Glassy Polymers
Authors: Paterson Russell , Yampol’skii Yuri , Fogg Peter G. T. , Bokarev Alexandre , Bondar Valerii , Ilinich Oleg , Shishatskii Sergey
Published: March 2007

Solubility of gases in polymers is an important property of polymeric materials relevant to many practical applications. Sorption of small molecules in polymers is a fundamental concern in such areas as food packaging, beverage storage, and polymer processing. However, by far the main interest in the solubility of gases in polymers, and especially in glassy polymers, is related to development of novel advanced materials for gas separation membranes. This is because the concentration gradient of a dissolved gas is the driving force of membrane processes. Development of these novel separation methods resulted in a rapid accumulation, in the recent literature, of thermodynamic data related to the solubility of gases in polymers at different temperatures and pressures. Polymers can be regarded as special cases of media intermediate between liquids and solids. As a consequence, modeling of gas sorption in polymers is very difficult and presents a permanent challenge to theoreticians and experimenters. The collection and critical evaluation of solubility data for various gas–polymer systems is relevant to both practical aspects of polymer applications and to fundamental studies of polymer behavior. This volume of the IUPAC-NIST Solubility Data Series summarizes the compilations and critical evaluations of the data on solubility of gases in glassy polymers. It is implied in this edition that “gases” are the components that are either permanent gases (supercitical fluids) or have saturated vapor pressure more than 1 atm at ambient conditions (298 K). The polymeric components of compilations and critical evaluations are primarily high molecular mass, amorphous, linear (noncross-linked) compounds that have the glass transition temperatures above ambient temperature. The data for each gas–polymer system have been evaluated, if the results of at least three independent and reliable studies have been reported. Where the data of sufficient accuracy and reliability are available, values are recommended, and in some cases smoothing equations are given to represent variations of solubility with changes in gas pressure and temperature. Referenced works are presented in the standard IUPAC-NIST Solubility Data Series format. Depending on the gas–polymer system, reported data are given in tabular form or in the form of sorption isotherms. The data included in the volume comprise solubilities of 30 different gases in more than 80 primarily amorphous homo and copolymers. Where available, the compilation or critical evaluation sheets include enthalpies of sorption and parameters for sorption isotherms. Throughout the volume, SI conventions have been employed as the customary units in addition to the units used in original publications.
IUPAC-NIST Solubility Data Series 68. Halogenated Aliphatic Hydrocarbon Compounds C3–C14 With Water
Authors: Horvath Ari L. , Getzen Forrest W.
Published: March 2007

This volume covers the solubilities of halogenated aliphatic C3–C14 compounds with water, heavy water, and electrolyte solutions. All data were critically examined for their reliability and best value estimates were selected on the basis of such evaluations. Referenced works are presented in the standard IUPAC-NIST Solubility Data Series format. Reported and best value data are presented in tabular form and, where justified, data correlation equations and graphical illustrations are provided. Throughout the volume, SI conventions have been employed as the customary units. The importance of these data arises from the fact that halogenated aliphatics have considerable commercial uses in a variety of applications such as industrial chemicals, process raw materials, solvents, and the like. In such applications they are often in contact with water and are routinely exposed to the atmosphere. Sometimes such contact and exposure results from spillage, leakage, or mishandling. Reliable data are essential for concentration estimates for the halogenated aliphatics in drinking and ground water, foodstuffs, human tissue, marine organisms, and the atmosphere. The halogenated aliphatics are of particular interest to health scientists, engineers, environmentalists, and atmospheric chemists in that they represent a class of chemical materials which has many significant industrial applications. However, at the same time, some of this class of substances have been shown to be carcinogenic and also to be especially harmful for the earth’s atmospheric and natural water composition. Indeed, the chemical reactivity of some halogenated aliphatics has resulted in atmospheric ozone depletion. The high ozone depletion potentials of such chemical substances emphasizes the importance of having available complete, accurate, and reliable data for mutual solubilities with water. The availability of such data is essential for estimates of halogenated aliphatic hydrocarbon levels in both natural water and aqueous industrial liquids which result from industrial fabrication, industrial liquids which result from industrial fabrication, industrial waste removal processes, and the like. The data also provide significant solubility values for studies concerning the health of humans and other biological systems.
IUPAC-NIST Solubility Data Series 69. Ternary Alcohol–Hydrocarbon–Water Systems
Authors: Skrzecz Adam , Shaw David G. , Maczynski Andrzej , Skrzecz Adam
Published: March 2007

The mutual solubilities of ternary systems containing alcohols, hydrocarbons and water are reviewed. An exhaustive search of the literature was attempted for numerical data on all alcohols and hydrocarbons which are liquid at STP. Data were found for alcohols with up to nine carbon atoms, but mostly with fewer than four carbons. Data for a variety of hydrocarbon structural types were found including alkane, alkene, and arene. A total of 205 original studies treating 116 ternary systems which have been published through 1992 are compiled. For 47 systems sufficient data were available to allow critical evaluation. All solubility data are expressed as mass and mole fractions as well as the originally reported units. Similar reviews of the related binary systems have previously been prepared for the Solubility Data Series.
Properties of Materials and Systems of Importance to Environmental Fates and Remediation. III. Review of Previous Thermodynamic Property Values for Chromium and Some of its Compounds
Authors: Kirklin Duane R.
Published: March 2007

Twenty-seven (27) crystalline and aqueous chromium species from the NBS Tables of Chemical Thermodynamic Properties were selected based upon their possible importance to environmental fate and remediation processes. Their NBS files were studied to determine the sources of information and the methodology used to determine the NBS selected thermodynamic values. The NBS tables for chromium were compiled in 1966. A literature search was performed to determine the existence of additional data for these species. Documentary data are presented for the thermodynamic properties of these twenty-seven (27) species.
Nuthatches eavesdrop on variations in heterospecific chickadee mobbing alarm calls
Authors: Templeton Christopher N. , Greene Erick
Published: March 2007

Many animals recognize the alarm calls produced by other species, but the amount of information they glean from these eavesdropped signals is unknown. We previously showed that black-capped chickadees (Poecile atricapillus) have a sophisticated alarm call system in which they encode complex information about the size and risk of potential predators in variations of a single type of mobbing alarm call. Here we show experimentally that red-breasted nuthatches (Sitta canadensis) respond appropriately to subtle variations of these heterospecific “chick-a-dee” alarm calls, thereby evidencing that they have gained important information about potential predators in their environment. This study demonstrates a previously unsuspected level of discrimination in intertaxon eavesdropping.
Influence of odorant receptor repertoire on odor perception in humans and fruit flies
Authors: Keller Andreas , Vosshall Leslie B.
Published: March 2007

The olfactory system is thought to recognize odors with multiple odorant receptors (ORs) that are activated by overlapping sets of odorous molecules, ultimately generating an odor percept in the brain. We investigated how the odor percept differs between humans and
Drosophila melanogaster
fruit flies, species with very different OR repertoires. We devised high-throughput single fly behavior paradigms to ask how a given OR contributes to the odor percept in
Drosophila
. Wild-type flies showed dose- and stimulus-dependent responses to 70 of 73 odors tested, whereas mutant flies missing one OR showed subtle behavioral deficits that could not be predicted from the physiological responses of the OR. We measured human and fly judgments of odor intensity and quality and found that intensity perception is conserved between species, whereas quality judgments are species-specific. This study bridges the gap between the activation of olfactory sensory neurons and the odor percept.
Nonnatural protein–protein interaction-pair design by key residues grafting
Authors: Liu Sen , Liu Shiyong , Zhu Xiaolei , Liang Huanhuan , Cao Aoneng , Chang Zhijie , Lai Luhua
Published: March 2007

Protein–protein interface design is one of the most exciting fields in protein science; however, designing nonnatural protein–protein interaction pairs remains difficult. In this article we report a
de novo
design of a nonnatural protein–protein interaction pair by scanning the Protein Data Bank for suitable scaffold proteins that can be used for grafting key interaction residues and can form stable complexes with the target protein after additional mutations. Using our design algorithm, an unrelated protein, rat PLCδ
1
-PH (pleckstrin homology domain of phospholipase C-δ1), was successfully designed to bind the human erythropoietin receptor (EPOR) after grafting the key interaction residues of human erythropoietin binding to EPOR. The designed mutants of rat PLCδ
1
-PH were expressed and purified to test their binding affinities with EPOR. A designed triple mutation of PLCδ
1
-PH (ERPH1) was found to bind EPOR with high affinity (
K
D
of 24 nM and an IC
50
of 5.7 μM) both
in vitro
and in a cell-based assay, respectively, although the WT PLCδ
1
-PH did not show any detectable binding under the assay conditions. The
in vitro
binding affinities of the PLCδ
1
-PH mutants correlate qualitatively to the computational binding affinities, validating the design and the protein–protein interaction model. The successful practice of finding a proper protein scaffold and making it bind with EPOR demonstrates a prospective application in protein engineering targeting protein–protein interfaces.
Long-standing influenza vaccination policy is in accord with individual self-interest but not with the utilitarian optimum
Authors: Galvani Alison P. , Reluga Timothy C. , Chapman Gretchen B.
Published: March 2007

Influenza vaccination is vital for reducing infection-mediated morbidity and mortality. To maximize effectiveness, vaccination programs must anticipate the effects of public perceptions and attitudes on voluntary adherence. A vaccine allocation strategy that is optimal for the population is not necessarily optimal for an individual. For epidemic influenza, the elderly have the greatest risk of influenza mortality, yet children are responsible for most of the transmission. The long-standing recommendations of the Centers for Disease Control follow the dictates of individual self-interest and prioritize the elderly for vaccination. However, preferentially vaccinating children may dramatically reduce community-wide influenza transmission. A potential obstacle to this is that the personal utility of vaccination is lower for children than it is for the elderly. We parameterize an epidemiological game-theoretic model of influenza vaccination with questionnaire data on actual perceptions of influenza and its vaccine to compare Nash equilibria vaccination strategies driven by self-interest with utilitarian strategies for both epidemic and pandemic influenza. Our results reveal possible strategies to bring Nash and utilitarian vaccination levels into alignment.
Implications for invariant natural killer T cell ligands due to the restricted presence of isoglobotrihexosylceramide in mammals
Authors: Speak Anneliese O. , Salio Mariolina , Neville David C. A. , Fontaine Josette , Priestman David A. , Platt Nick , Heare Tanya , Butters Terry D. , Dwek Raymond A. , Trottein Francois , Exley Mark A. , Cerundolo Vincenzo , Platt Frances M.
Published: March 2007

Development of invariant natural killer T (iNKT) cells requires the presentation of lipid ligand(s) by CD1d molecules in the thymus. The glycosphingolipid (GSL) isoglobotrihexosylceramide (iGb3) has been proposed as the natural iNKT cell-selecting ligand in the thymus and to be involved in peripheral activation of iNKT cells by dendritic cells (DCs). However, there is no direct biochemical evidence for the presence of iGb3 in mouse or human thymus or DCs. Using a highly sensitive HPLC assay, the only tissue where iGb3 could be detected in mouse was the dorsal root ganglion (DRG). iGb3 was not detected in other mouse or any human tissues analyzed, including thymus and DCs. Even in mutant mice that store isoglobo-series GSLs in the DRG, we were still unable to detect these GSLs in the thymus. iGb3 is therefore unlikely to be a physiologically relevant iNKT cell-selecting ligand in mouse and humans. A detailed study is now warranted to better understand the nature of iNKT cell-selecting ligand(s)
in vivo
.
Folding and unfolding of a photoswitchable peptide from picoseconds to microseconds
Authors: Ihalainen Janne A. , Bredenbeck Jens , Pfister Rolf , Helbing Jan , Chi Lei , van Stokkum Ivo H. M. , Woolley G. Andrew , Hamm Peter
Published: March 2007

Using time-resolved IR spectroscopy, we monitored the kinetics of folding and unfolding processes of a photoswitchable 16-residue alanine-based α-helical peptide on a timescale from few picoseconds to almost 40 μs and over a large temperature range (279–318 K). The folding and unfolding processes were triggered by an ultrafast laser pulse that isomerized the cross linker within a few picoseconds. The main folding and unfolding times (700 ns and 150 ns, respectively, at room temperature) are in line with previous T-jump experiments obtained from similar peptides. However, both processes show complex, strongly temperature-dependent spectral kinetics that deviate clearly from a single-exponential behavior. Whereas in the unfolding experiment the ensemble starts from a well defined folded state, the starting ensemble in the folding experiment is more heterogeneous, which leads to distinctly different kinetics of the experiments, because they are sensitive to different regions of the energy surface. A qualitative agreement with the experimental data-set can be obtained by a model where the unfolded states act as a hub connected to several separated “misfolded” states with a distribution of rates. We conclude that a rather large spread of rates (

k
1

:

k
n

≈ 9) is needed to explain the experimentally observed stretched exponential response with stretching factor β = 0.8 at 279 K.
Zwitterionic self-assembly of
l
-methionine nanogratings on the Ag(111) surface
Authors: Schiffrin Agustin , Riemann Andreas , Auwärter Willi , Pennec Yan , Weber-Bargioni Alex , Cvetko Dean , Cossaro Albano , Morgante Alberto , Barth Johannes V.
Published: March 2007

The engineering of complex architectures from functional molecules on surfaces provides new pathways to control matter at the nanoscale. In this article, we present a combined study addressing the self-assembly of the amino acid
l
-methionine on Ag(111). Scanning tunneling microscopy data reveal spontaneous ordering in extended molecular chains oriented along high-symmetry substrate directions. At intermediate coverages, regular biomolecular gratings evolve whose periodicity can be tuned at the nanometer scale by varying the methionine surface concentration. Their characteristics and stability were confirmed by helium atomic scattering. X-ray photoemission spectroscopy and high-resolution scanning tunneling microscopy data reveal that the
l
-methionine chaining is mediated by zwitterionic coupling, accounting for both lateral links and molecular dimerization. This methionine molecular recognition scheme is reminiscent of sheet structures in amino acid crystals and was corroborated by molecular mechanics calculations. Our findings suggest that zwitterionic assembly of amino acids represents a general construction motif to achieve biomolecular nanoarchitectures on surfaces.
Pathogen-induced reversal of native dominance in a grassland community
Authors: Borer Elizabeth T. , Hosseini Parviez R. , Seabloom Eric W. , Dobson Andrew P.
Published: March 2007

Disease may play a critical role in invasions by nonnative plants and animals that currently threaten global biodiversity. For example, a generalist viral pathogen has been recently implicated in one of the most extensive plant invasions worldwide, the invasion and domination of California's perennial grasslands by exotic annual grasses. To date, disease has never been quantitatively assessed as a cause of this invasion. Using a model with field-estimated parameters, we demonstrate that pathogen presence was necessary to reverse competitive outcome and to allow exotic annual grass invasion and dominance. Although pathogen-induced reversal of a competitive hierarchy has been suggested as a mechanism of species invasion, here we quantitatively demonstrate the importance of this phenomenon by using field-derived parameters in a dynamical model. Pathogen-mediated reversals in competitive balance may be critically important for understanding past, and predicting future, invasions.
Genome-wide coorientation of replication and transcription reduces adverse effects on replication in
Bacillus subtilis
Authors: Wang Jue D. , Berkmen Melanie B. , Grossman Alan D.
Published: March 2007

In many bacteria, there is a strong bias for genes to be encoded on the leading strand of DNA, resulting in coorientation of replication and transcription. In
Bacillus subtilis
, transcription of the majority of genes (75%) is cooriented with replication. By using genome-wide profiling of replication with DNA microarrays, we found that this coorientation bias reduces adverse effects of transcription on replication. We found that in wild-type cells, transcription did not appear to affect the rate of replication elongation. However, in mutants with reversed transcription bias for an extended region of the chromosome, replication elongation was slower. This reduced replication rate depended on transcription and was limited to the region in which the directions of replication and transcription are opposed. These results support the hypothesis that the strong bias to coorient transcription and replication is due to selective pressure for processive, efficient, and accurate replication.