bluuebunny/crossref_metadata_2025 huggingface dataset:
Stepwise Layering of Helium Films on Solid Hydrogen
Authors: Cieslikowski D. , Leiderer P. , Dahm A. J.
Published: March 2014

The mobility of surface bound electrons is monitored as helium is adsorbed on a hydrogen substrate. Maxima in the mobility occur at the completion of each helium monolayer. Up to nine maxima are observed, indicating that stepwise layering occurs for at least nine layers. A smooth variation of the mobility with further helium adsorption indicates that continuous wetting occurs.
Hot Electron Energy Relaxation Rates in a HgCdTe Superlattice
Authors: Echternach P. M. , Friedman L. J. , Gould C. M. , Bozler H. M. , Cheung J. T.
Published: March 2014

We have measured the electron energy relaxation rate in the conduction layers of a HgCdTe superlattice at temperatures between 20 - 200 mK. The purpose of this measurement is to compare the energy relaxation rates of hot electrons with those of other 2d electron systems such as GaAs/AlGaAs multiple quantum wells which we have previously reported. The sample consists of 24 periods of 240 Å layers of HgxCd1-x Te with x = 0.55 alternating with x = 0.15. The resistance of this material exhibits a log
(T) dependence from 10 K to below 40 mK. The energy relaxation rate is consistent with electron-phonon coupling as seen previously in both GaAs and thin films of copper.
Phase Transitions in the Frustrated ABX3 Compounds
Authors: Ajiro Yoshitami , Kikuchi Hikomitsu , Nakashima Takeru , Unno Yasuyuki
Published: March 2014

In connection with the spin frustration, the phase transitions of hexagonal ABX3 compounds are experimentally studied. For the XY-like CsMnBr3, it is revealed that the phase transition belongs to a new universal class governed by Z2×S1 symmetry. It is also revealed that though the phase transition is well established, the ordered phase in this substance as well as the intermediate phases in the Ising-like CsCoCl3, CsCoBr3 and CsNiCl3 dynamically fluctuate in a time scale slightly longer than the observation time of neutron diffraction. Crucial effects of strong one-dimensionality of the substances are discussed.
Transverse Freezing in the Quantum Ising Spin Glass
Authors: Kopec Tadeusz K.
Published: March 2014

The effect of a transverse field on the spin glass freezing in the Sherrington-Kirkpatrick S = 1/2 quantum Ising model is studied using the thermo-field dynamics as the substitute of the n-replica trick. The field dependent transition line to the spin glass phase is found and the averaged local static susceptibility in the transverse direction is calculated in the mean field approximation.
Correlations between Transport Properties and Valence Band Spectra of Thin Films of Nb1-xSix
Authors: Söldner KARIN , Saemann-Ischenko Georg
Published: March 2014

Thin films of Nb1-xSix were prepared by cosputtering from two magnetron cathodes. The electronic structure was investigated by UPS- and XPS-spectra, which were taken without breaking the vacuum. The atomic structure was studied by X-ray diffraction. The results were correlated with resistivity measurements.
Antiferromagnetic Ordering in the Ternary Rare Earth Cobalt Borides RCo4B4 (R=Ce, Gd, Tb, Dy, Ho, Er, Tm, Lu)
Authors: Ku H. C. , Tai M. F. , Klavins P. , Shelton R. N.
Published: March 2014

Antiferromagnetic Néel temperatures (T
N
) are reported for magnetic rare earth cobalt compounds RCo4B4 (R=Gd, Tb, Dy, Ho, Er, Tm) which crystallize with the primitive tetragonal CeCo4B4-type structure. The maximum T
N
of 3.68 K was observed in TbCo4B4, while TmCo4B4 has the lowest ordering temperature of 0.17 K. No magnetic transition was observed for CeCo4B4 and LuCo4B4 down to 60 mK. The complex evolution from antiferromagnetic order in HoCo4B4 (T
N
=1.91 K) to ferromagentic order in HoRh4B4 (T
C
=6.56 K) of the pseudoternary system Ho(Rh1-x
Co
x
)4B4 is briefly discussed.
Role of Hole-Carriers in the Electrical Resistivity of Ferromagnetic Metals and Alloys
Authors: Ikeda Kôki
Published: March 2014

The detailed study on the correlation between the electrical resistivity and ferromagnetism was made in a series of Ni-base alloys containing Fe, Co, Cu, Zn, Al, Ga, Si and Ge. The proportional relation between the magnetic resistivity above the Curie temperature and the de Gennes factor, which was predicted by the localized-spin model, was found exceptionally for few Ni-base alloys containing a negligibly small number of hole-carriers. It is pointed out that the hole-carrier, which is observed in the ordinary Hall effect or the resistivity due to the phonon scattering, behaves as the probability of interband s-d transitions in the magnetic scattering process.
Magnetic Interactions in Five-Coordinated Iron (III) Complexes with Spin S=3/2
Authors: Oka Shinsuke , Idogaki Toshihiro , Uryû Norikiyo
Published: March 2014

The trivalent iron in Fe[S2CN(C2H5)2]2X, where X=Cl,Br,I, exhibits an unusual spin state of 3/2. The exchange interactions in the iodo complex are assumed to be of dimeric character from the crystal structure. On the basis of the dimer model, the magnetic specific heat of iodide has been analyzed taking the inter-dimer interaction into account by the Oguchi approximation. The other magnetic properties have also been discussed. Furthermore, the discussion has been made for the cases of chloro and bromo complexes in a comparative way.
Principle of Corresponding States of Magnetic Phase Diagram of CuCl2·2H2ZO at Low Temperatures and High Pressures
Authors: Takeda Kazuyoshi , Idogaki Toshihiro , Tsuru Kazuo , Uryû Norikiyo , Inoue Masaru
Published: March 2014

The principle of corresponding states of the magnetic phase diagram of CuCl2·2H2O (TN=4.35K) at low-temperatures, hydrostatic pressures and magnetic fields has been studied by the low-temperature heat capacity measurements. The Néel temperature TN(p) has changed linearly with pressure p(kbar) as TN(p)=TN(0)(1+0.048p) up to 6 kbar at zero external field. The dependence of magnetic interactions on pressure (or inter-ion distance) is revealed to give the larger value of the magnetic Grüneisen constant than expected for the superexchange mechanism. The phase boundary between paramagnetic and antiferromagnetic phases has been examined at high hydrostatic pressures and magnetic fields applied along the spin easy axis. The principle of corresponding states of the magnetic phase diagram of this compound has been checked by a molecular field approximation in the consideration of the pressure dependence of magnetic interactions and anisotropies.
Two-Level System Constituted by Trapped Deuterium in Nb and Ta
Authors: Cannelli G. , Cantelli R. , Cordero F.
Published: March 2014

The two-level system (TLS) model is used to interpret the anelastic relaxation observed in the Nb–O (N) –D and Ta–O (N) –D systems at low temperature. In Ta there is clear evidence that the TLS interact mainly with the conduction electrons.
Heat Capacity and Resistivity Measurements of the Icosahedral Phase of Al6CuLi3
Authors: Jin A. , Finotello D. , Gillis K. A. , Maynard J. D. , Bartges C. , Ryba E. , Chan M. H. W.
Published: March 2014

We report AC heat capacity measurements of the icosahedral phase of Al6CuLi3 between 0.25 and 2.7 K. These Camples are cast in ingots and are composed of interdendritic regions of quasi-crystal phase (0.1 mm × 3.0 mm) interlaced with an Al and R-phase solid solution (13% of sample). Heat capacity and resistivity measurements both indicate a superconducting transition of about 1.4 K for these samples. The relative contribution from the icosahedral phase and the aluminum to the properties of the sample are discussed.
Electrical Transport Properties of TMBEDT-TTF Salts
Authors: Freund M. M. , Olsen J. L. , Wallis J. , Karrer A. , Dunitz J. D. , Hilti B.
Published: March 2014

We have measured electrical transport properties of a new family of organic charge-transfer salts derived from the donor molecule TMET (S,S,S,S- bis(dimethyl-ethylenedithio)tetrathiofulvalene) as a function of temperature, pressure, magnetic field, and electric current. We find several discontinuities in the resistivity for these low-dimensional nonlinear conductors in the temperature range from 1.5 K to 300 K. For the (TMET)3(ClO4)2 salts we found an activation law with an energy gap Δ≃2 meV at temperatures below 10 K.
Equation for the Conductivity of Hetrogeneous Binary Media
Authors: McLachlan David S.
Published: March 2014

An equation is presented which describes the conductivity (resistivity) of a wide variety of binary macroscopic mixtures as a function of the conductivities (resistivities) of the components, the volume (area) fraction of each, and two morphology parameters. For metal-insulator and normal-superconductor systems the equation has the mathematical form of the percolation equation. In this paper the Ge–Aℓ (4.2K and 300K-) and Ge–Pb (8K and 300K) metal-insulator systems are shown to fit this equation, well within the experimental accuracy.
Local Phonon Model of Strongly Coupled Superconductors
Authors: Matsuura Tamifusa , Miyake Kazumasa
Published: March 2014

A local-phonon model of strongly coupled superconductors, such as A15, C15, etc., is investigated with attention to the change of the properties, both in the superconducting and normal' states, corresponding to the change of the strength of the electron-phonon coupling. As the coupling is increased, the nature of the effective ionic potential changes from single- to double-well type; accordingly, the on-site pairing interaction due to the local-phonon exchange changes from attractive to repulsive one. In the latter case, therefore, the inter-site pairing interaction due to the quasi-spin (electric dipole) fluctuations are expected to be important; so that the superconducting state becomes anisotropic in a form or another, which seems to be consistent with recent experiments measuring the density of states for the low energy excitations.
Anomalous Behavior in Electrical Resistivity and Specific Heat of Superconducting TiNb Alloys
Authors: Sasaki Takako , Hanada Shuji , Muto Yoshio
Published: March 2014

The electrical resistivity and specific heat of TiNb alloys have been measured in high magnetic fields up to 20.6 T and 15.1 T, respectively. Anomalous behavior is observed in both electrical resistivity and specific heat. A slight but definite enhancement of the resistivity with logarithmic temperature dependence is observed for samples with Nb concentration lower than 63 at%, where ω-precipitation in β matrix is clear in electron diffraction pattern. An abrupt change in the slope of the normal state specific heat Cn/T plotted as a function of T2 is found in samples over a wide range of concentration.
Superconducting Properties of V–Al Thin Films Prepared by DC Magnetron Sputtering
Authors: Ishida Hiroyuki , Ohshima Shigetoshi , Wakiyama Tokuo
Published: March 2014

V–Al thin films were prepared by DC magnetron sputtering. The dependences of the superconducting transition temperature(Tc) were studied on the composition of the films and on the deposition temperature(Td). A maximum Tc midpoint of 13.0K was obtained for the film with the Al content of 18.5at% prepared at Td of 600°C on glazed alumina substrate. Effects of substrate surfaces on the formation of A15 V3Al were studied. Three different surfaces of non-, Ag- and Au-coated sapphire substrates were prepared. Values of Tc and phases of the films changed significantly with the difference of the coating material. It was found that gold has great effects on suppressing the formation of stable bcc phase and on stabilizing the formation of the metastable A15 phase.
Stochastic Formulation of Vortex Tangle Turbulence in Superfluid 4He
Authors: Yamada Kazuo , Kashiwamura Shohei
Published: March 2014

Stochastic theory of vortex tangle turbulence in superfluid 4He is reformulated to extend Schwarz theory to spatially inhomogeneous case. Starting with the equation of motion for superfluid velocity under an arrangement of vortex tangle, the equation of motion for the vortex line element is described by a Langevin type equation and Fokker-Planck type equation is derived for the distribution function of vortex line length. Assuming a scaling hypothesis of velocity and an universal property of the distribution function, the extended formula of Vinen- Schwarz equation is derived. By taking the average of starting equation over stochastic process, the hydrodynamical equation for the superfluid velocity can be written in a form with the mutual friction force and “eddy viscosity” term.
The Influence of N-Ion Irradiation on Superconducting TiN
Authors: Thompson J. R. , Ellis J. T. , Christen D. K. , Sekula S. T. , Lewis J. D. , Williams J. M.
Published: March 2014

The influence of disorder on the properties of the B1 phase superconductive compound titanium nitride has been investigated. Following synthesis and characterization of thin films of TiN, the materials were disordered progressively and uniformly by irradiation with nitrogen ions. The superconducting transition temperature Tc decreased and the low temperature electrical resistivity ρ increased as lattice damage was introduced. The dependence of both Tc and ρ on N-ion fluence φ could be described by exponentially saturating functions of φ with similar rate constants. These constants correspond to characteristic damage energy densities of 14 and 12 eV/atom, respectively.
Magnetization of Superconducting LaAl2 Single Crystals
Authors: Vlcek B. , Seidl E. , Weber H. W.
Published: March 2014

Magnetization and critical field measurements were carried out on a high-purity LaAl2 single crystal (RRR = 830) in the temperature range from 80 mK to the transition temperature (Tc=3.301 K). The material was identified to be a type-II superconductor with κ(Tc)=0.75±0.01 and µ0Hc2(0)=92.04 mT. As expected from the magnitude of κ, evidence for a first-order phase transition at Hcl is found. Experiments on the anisotropy of Hc2 in the (100)-plane show a field modulation of about 1% at 2 K. A complete evaluation of superconductive parameters will be presented.
Study of Mechanically Alloyed, Amorphous Co–Zr and Ni–Zr Powders by Superconductivity Measurements
Authors: Thomä A. , Saemann-Ischenko G. , Schultz L. , Hellstern E.
Published: March 2014

Measurements of the superconducting transition temperature Tc, the crystallization temperature Tx and X-ray diffraction patterns of mechanically alloyed TMxZr1-x (TM = Ni, Co) are reported. For x ≥ 0.30 the results obtained for Tc and Tx closely resemble literature data of rapidly quenched amorphous samples of the same composition. The superconductivity measurements therefore show the amorphous nature of the mechanically alloyed material. For x ≤ 0.25 the Tc- and Tx-data as well as the appearance of crystalline diffraction lines lead to the conclusion that in this composition range an amorphous phase with x ≃ 0.28 in the case of Co, and x ≃ 0.27 in the case of Ni, respectively, coexists in metastable equilibrium with ω-Zr.
High Temperature Superconductors: Electronic Structure Changes due to Replacement of La with Ba and Sr in the Cu–O-Based Systems
Authors: Krakauer H. , Picket W. E. , Papaconstantopoulos D. A. , Boyer L. L.
Published: March 2014

The replacement of some La in La2CuO4 with divalent atoms has been found to lead to high temperature superconductivity with Tc=30-40 K. These superconductors have a bet layer perovskite structure with large anisotropies in their electronic band structure. Using first principles local density methods applied to both layer perovskite and the related cubic perovskite structures, we find that alloying on the La site leads to large changes in the chemical bonding of both structures, except near the Fermi level where a rigid band picture is reasonable. Large changes in the spectral density near the “dopant” atom occurs on both the nearby O and Cu atoms, and is not simply described by a Cu(2+)-Cu(3+) valence change. These results are consistent with recent x-ray absorption studies by Tranquada et al.
Tunneling Measurements of the Energy Gap in High Tc Oxide Superconductors
Authors: Kirtley J. R. , Tsuei C. C. , Park S. I. , Chi C. C. , Rozen J. , Shafer M. W. , Gallagher W. J. , Sandstrom R. L. , Dinger T. R. , Chance D. A.
Published: March 2014

We have measured the current-voltage (I-V) characteristics for tunneling into the high critical temperature superconducting materials La-Sr-Cu-O and Y-Ba-Cu-O. We find superconducting energy gaps that are consistent with strong coupling superconductivity in both materials. We find no significant differences in the measured gaps when the tunneling tip approaches a single crystal of Y-Ba-Cu-O from a direction normal to the CuO planes, as opposed to parallel to them. There are structures in the conductance-voltage characteristics above the gap energy that can occasionally have very large amplitudes. The physical origin of this structure is not certain. However, its presence makes it difficult to obtain quantitative information on the electron-phonon coupling strength from such tunneling measurements.
A High-power Tapered-SAN Laser for an Optical Pick-up
Authors: Kumagai Osamu , Ohata Toshiharu , Sato Hiromitsu , Horii Shinichi , Mamine Takayoshi , Kojima Chiaki
Published: March 2014

A high-power laser with a tapered stripe structure has been developed and demonstrated to have a small aspect ratio in far field pattern, a small astigmatic distance, and good reliability. The beam divergence in the parallel direction can be controlled by varying the shape of the tapered stripe. This laser makes it possible to building up a compact, low cost optical pick-up for magneto-optical disk drives.
Spherical Grating Objective Lenses for Optical Disk Pick-ups
Authors: Goto Kenya , Mori Kazushige , Hatakoshi Genichi , Takahashi Shunsuke
Published: March 2014

Plane grating collimator lenses [GCLs] and spherical grating objective lenses [SGLs] have been developed and installed in different optical pick-ups for CD players. The relief profile for the grating lenses have been designed to obtain high diffraction power efficiency of about 80% for the GCLs and about 65% for the SGLs. The blazed grating profile has been engraved by diamond turning lathes. GCLs were mass-produced by the plastic injection molding method and installed in more than 80 thousand optical pick-ups for portable and general audio use. SGLs have a much higher NA and can be used as objectives for the optical pick-ups. A thin plastic relief grating profile for the SGLs is formed by the photo-polymerization method on a flat face of a piano-spherical glass substrate. The field angle for the SGLs is more than ±0.5 degree, within the Marechel Criterion.
High-Density Magneto-Optic Disk Using Highly Controlled Pit-Edge Recording
Authors: Sukeda Hirofumi , Ojima Masahiro , Takahashi Masahiko , Maeda Takeshi
Published: March 2014

High-density pit-edge recording on magneto-optic disks has been achieved with accurate edge control. Storage density of 0.7 µm/bit is obtained by suppressing timing jitters caused by (1) teardrop-shaped magnetic domains and (2) thermal interaction between magnetic domains.
Reliability Test of Write-Once Optical Disk
Authors: Okino Yoshihiro
Published: March 2014

Reliability test of write once optical disks offered by nine disk manufacturers was performed by the Japanese Standard Committee of Optical Digital Data Disk in OITDA. Measuring items and methods, accelerated test conditions and the results are described.
Transient Measurement of Laser Induced Phase Transition in In–Sb Alloy Films
Authors: Sun Yang , Deng He , Gan Fuxi
Published: March 2014

The reflectance transient change of In-Sb alloy films under 1.06 urn laser irradiation was measured The reflectance change occured after the laser pulse, and lasted several microseconds. The phase transition from amorphous to crystal was observed. The reflectance change amplitude can reach about 30%. Transmission electron microscope (TEM) and optical microscope was used to measure the morphologies and structures of the laser irradiation area. The transition process in the films was deduced.
Photochemical Hole Burning Materials: Dye Molecules and Matrices
Authors: Tani Toshiro , Itani Akira , Uno Yasuhiro , Sakuda Makoto
Published: March 2014

In this paper we describe our recent studies on the properties of photochemical hole burning of organic dye molecules, mainly 1,4-dihydroxyanthraquinone and its related molecules, in variety of organic or inorganic glassy matrices. Electronic and structural conditions for the formation of stable holes are discussed in addition to the significant role of the matrices and the effect in disordered systems. Hence we try to deduce the problems to be overcome and to construct our basic ideas on designing the materials for the future wavelength multiplexed data storage.
Test particle comparison of heavy atomic and molecular ion distributions at Mars
Authors: Curry S. M. , Liemohn M. , Fang X. , Ma Y. , Slavin J. , Espley J. , Bougher S. , Dong C. F.
Published: March 2014

This study uses the Mars Test Particle simulation to create virtual detections of O+, , and in an orbital configuration in the Mars space environment. These atomic and molecular planetary pickup ions are formed when the solar wind directly interacts with the neutral atmosphere, causing the ions to be accelerated by the background convective electric field. The subsequent ion escape is the subject of great interest, specifically with respect to which species dominates ion loss from Mars. O+ is found to be the dominant escaping ion because of the large sources of transported ions in the low‐energy (<10 eV) and high‐energy (>1 keV) range. and are observed at these energy ranges but with much lower fluxes and are generally only found in the tail between 10 eV and 1 keV. Using individual particle traces, we reveal the origin and trajectories of the low‐energy downtail O+ populations and high‐energy polar O+ populations that contribute to the total escape. Comparing them against and reveals that the extended hot oxygen corona contributes to source regions of high‐ and low‐energy escaping ions. Additionally, we present results for solar minimum and maximum conditions with respect to ion fluxes and energies in order to robustly describe the physical processes controlling planetary ion distributions and atmospheric escape.
The Role of Emotions and Assumptions in Culturally Responsive Financial Education Practice in a Capitalist Economy
Authors: Tisdell Elizabeth J.
Published: March 2014

This chapter discusses some of the assumptions of financial education, and then considers the role of emotions, beliefs, and attitudes in culturally responsive financial education practice.
Systematic Doping Control of CVD Graphene Transistors with Functionalized Aromatic Self‐Assembled Monolayers
Authors: Cernetic Nathan , Wu Sanfeng , Davies Joshua A. , Krueger Benjamin W. , Hutchins Daniel O. , Xu Xiaodong , Ma Hong , Jen Alex K.‐Y.
Published: March 2014

Recent reports have shown that self‐assembled monolayers (SAMs) can induce doping effects in graphene transistors. However, a lack of understanding persists surrounding the quantitative relationship between SAM molecular design and its effects on graphene. In order to facilitate the fabrication of next‐generation graphene‐based devices it is important to reliably and predictably control the properties of graphene without negatively impacting its intrinsic high performance. In this study, SAMs with varying dipole magnitudes/directions are utilized and these values are directly correlated to changes in performance seen in graphene transistors. It is found that, by knowing the z‐component of the SAM dipole, one can reliably predict the shift in graphene charge neutrality point after taking into account the influence of the metal electrodes (which also play a role in doping graphene). This relationship is verified through density functional theory and comprehensive device studies utilizing atomic force microscopy, X‐ray photoelectron spectroscopy, Raman spectroscopy, and electrical characterization of graphene transistors. It is shown that properties of graphene transistors can be predictably controlled with SAMs when considering the total doping environment. Additionally, it is found that methylthio‐terminated SAMs strongly interact with graphene allowing for a cleaner graphene transfer and enhanced charge mobility.
Terahertz Plasmonic Structures Based on Spatially Varying Conductivities
Authors: Gupta Barun , Pandey Shashank , Guruswamy Sivaraman , Nahata Ajay
Published: March 2014

Terahertz plasmonic structures are demonstrated in which the conductivity of the metallic film is varied spatially in order to further enhance the response. Using a commercially available inkjet printer, in which one cartridge is filled with conductive silver ink and a second cartridge is filled with resistive carbon ink, computer generated drawings of plasmonic structures are printed in which the individual printed dots can have differing amounts of the two inks, thereby creating a spatial variation in the conductivity. The silver ink has a DC conductivity that is only a factor of six lower than bulk silver, while the carbon ink acts as a lossy dielectric at THz frequencies. Both inks sinter at room temperature immediately after contact with the plastic film. Using a periodic array of subwavelength apertures as a test structure, patterns printed with different fractional amounts of the two inks show dramatically different enhanced optical transmission properties. These differences arise from changes in the propagation loss properties as a function of conductivity. This data is used to design and fabricate aperture arrays in which the conductivity varies spatially. The resulting plasmonic effect is found to dramatically alter the spatial beam profile of the transmitted THz radiation, as measured by THz imaging.
Steroid‐eluting sinus implant for in‐office treatment of recurrent nasal polyposis: a prospective, multicenter study
Authors: Lavigne François , Miller Steven K. , Gould Andrew R. , Lanier Brent J. , Romett J. Lewis
Published: March 2014

Background

Treatment options for chronic rhinosinusitis with recurrent polyposis (CRSwNP) after endoscopic sinus surgery (ESS) are limited, and include frequent use of systemic steroids and revision surgery. A bioabsorbable, steroid‐eluting implant was studied for its ability to dilate sinuses obstructed by polyps and provide localized, controlled steroid delivery to reestablish sinus patency. This study assessed the initial feasibility, safety, and efficacy of steroid‐eluting implants placed in the office setting in patients who were candidates for revision ESS.

Methods

Prospective, multicenter study enrolling 12 patients who had prior ESS but experienced recurrent polyposis refractory to medical therapy. Implants were placed bilaterally under topical anesthesia in‐office. Follow‐up through 6 months included endoscopic grading, patient‐reported outcomes (22‐item Sino‐Nasal Outcomes Test [SNOT‐22]) and need for revision ESS.

Results

Implants were successfully inserted in 21 of 24 (88%) ethmoid sinuses, resulting in 11 evaluable patients. No serious adverse events occurred. Within 1 month, mean bilateral polyp grade was reduced from 4.5 at baseline to 2.3 (p = 0.008) and sustained through 6 months (2.33; p = 0.008). Mean SNOT‐22 score was significantly improved from 2.19 at baseline to 0.90 within 1 month (p = 0.001) and sustained to 6 months (1.03; p = 0.012). Sixty‐four percent of patients were no longer revision ESS candidates at 6 months.

Conclusion

The study provided initial clinical evidence of the feasibility, safety, and efficacy of in‐office steroid‐eluting implant placement in CRS patients with recurrent polyposis after ESS. Although further studies are needed, the results suggest this therapy may provide a safe and effective, office‐based option for the treatment of obstructive polyposis.
Formation and Thermal Stability of Gold–Silica Nanohybrids: Insight into the Mechanism and Morphology by Electron Tomography
Authors: Kundu Paromita , Heidari Hamed , Bals Sara , Ravishankar N. , Van Tendeloo Gustaaf
Published: March 2014

Gold–silica hybrids are appealing in different fields of applications like catalysis, sensorics, drug delivery, and biotechnology. In most cases, the morphology and distribution of the heterounits play significant roles in their functional behavior. Methods of synthesizing these hybrids, with variable ordering of the heterounits, are replete; however, a complete characterization in three dimensions could not be achieved yet. A simple route to the synthesis of Au‐decorated SiO2 spheres is demonstrated and a study on the 3D ordering of the heterounits by scanning transmission electron microscopy (STEM) tomography is presented—at the final stage, intermediate stages of formation, and after heating the hybrid. The final hybrid evolves from a soft self‐assembled structure of Au nanoparticles. The hybrid shows good thermal stability up to 400 °C, beyond which the Au particles start migrating inside the SiO2 matrix. This study provides an insight in the formation mechanism and thermal stability of the structures which are crucial factors for designing and applying such hybrids in fields of catalysis and biotechnology. As the method is general, it can be applied to make similar hybrids based on SiO2 by tuning the reaction chemistry as needed.
Switching Demethylation Activities between AlkB Family RNA/DNA Demethylases through Exchange of Active‐Site Residues
Authors: Zhu Chenxu , Yi Chengqi
Published: March 2014

The AlkB family demethylases AlkB, FTO, and ALKBH5 recognize differentially methylated RNA/DNA substrates, which results in their distinct biological roles. Here we identify key active‐site residues that contribute to their substrate specificity. Swapping such active‐site residues between the demethylases leads to partially switched demethylation activities. Combined evidence from X‐ray structures and enzyme kinetics suggests a role of the active‐site residues in substrate recognition. Such a divergent active‐site sequence may aid the design of selective inhibitors that can discriminate these homologue RNA/DNA demethylases.
Direct UV‐Induced Functionalization of Surface Hydroxy Groups by Thiol–Ol Chemistry
Authors: Li Linxian , Li Junsheng , Du Xin , Welle Alexander , Grunze Michael , Trapp Oliver , Levkin Pavel A.
Published: March 2014

A novel UV‐initiated surface modification method for the direct functionalization of surface hydroxy groups with thiol‐containing molecules (termed “thiol–ol” modification) is described. This method is based on the oxidative conjugation of thiols to hydroxy groups. We demonstrate that different thiol‐containing molecules, such as fluorophores, thiol‐terminated poly(ethylene glycol) (PEG‐SH), and a cysteine‐containing peptide, can be attached onto the surface of porous poly(2‐hydroxyethyl methacrylate‐co‐ethylene dimethacrylate). Direct functionalization of other hydroxy‐group‐bearing surfaces, fabrication of micropatterns, and double patterning have been also demonstrated using the thiol–ol method.
Antimicrobial Poly(2‐methyloxazoline)s with Bioswitchable Activity through Satellite Group Modification
Authors: Krumm Christian , Harmuth Simon , Hijazi Montasser , Neugebauer Britta , Kampmann Anne‐Larissa , Geltenpoth Helma , Sickmann Albert , Tiller Joerg C.
Published: March 2014

Biocides are widely used for preventing the spread of microbial infections and fouling of materials. Since their use can build up microbial resistance and cause unpredictable long‐term environmental problems, new biocidal agents are required. In this study, we demonstrate a concept in which an antimicrobial polymer is deactivated by the cleavage of a single group. Following the satellite group approach, a biocidal quaternary ammonium group was linked through a poly(2‐methyloxazoline) to an ester satellite group. The polymer with an octyl‐3‐propionoate satellite group shows very good antimicrobial activity against Gram‐positive bacterial strains. The biocidal polymer was also found to have low hemotoxicity, resulting in a high HC50/MIC value of 120 for S. aureus. Cleaving the ester satellite group resulted in a 30‐fold decrease in antimicrobial activity, proving the concept valid. The satellite group could also be cleaved by lipase showing that the antimicrobial activity of the new biocidal polymers is indeed bioswitchable.
Affinity precipitation of a monoclonal antibody from an industrial harvest feedstock using an ELP‐Z stimuli responsive biopolymer
Authors: Sheth Rahul D. , Jin Mi , Bhut Bharat V. , Li Zhengjian , Chen Wilfred , Cramer Steven M.
Published: March 2014

In this work, a proof of concept elastin‐like polypeptide‐Z domain fusion (ELP‐Z) based affinity precipitation process is developed for monoclonal antibody (mAb) purification from industrial harvest feeds. Greater than 99% mAb recoveries are obtained during the initial binding step of the process for both pure mAb and the mAb harvest feeds. Great than 90% overall mAb yields are also obtained for the subsequent elution step of the process with no measurable mAb aggregation. The process is shown to result in more than 2 logs of host cell protein (HCP) and more than 4 logs of DNA clearance from the harvest feed. While the overall mAb yield and HCP clearance for the affinity precipitation process was comparable to Protein A chromatography the DNA clearance was clearly superior. Performance is maintained for mAb final elution concentrations up to 20 g/L, demonstrating the ability of the process to both concentrate and purify the mAb. Effective ELP‐Z regeneration is also demonstrated using 0.1 M NaOH with no adverse effect on subsequent capture efficiency. Finally, the reusability of the ELP‐Z construct and robustness of the process is demonstrated for up to three purification‐regeneration cycles with minimal product and impurity carryover and high yields and purity. This work demonstrates that the ELP‐Z based precipitation approach can be successfully employed as an affinity capture step for industrial mAbs. Biotechnol. Bioeng. 2014;111: 1595–1603. © 2014 Wiley Periodicals, Inc.
Activin A supplement in the hESCs culture enhances the endoderm differentiation efficiency
Authors: Guo Shuren , Mao Xiaohuan , He Fucheng , Liu Hongchun , Ming Liang
Published: March 2014

Activin A is a critical regulator in human embryonic stem cells (hESCs) maintenance and differentiation. Different concentrations of Activin A affect hESC maintenance and differentiation in different ways. A high concentration favors anterior primitive streak and gives rise to DE if the stimulation persists. hESCs were cultured with and without 10 ng/mL Activin A supplement respectively. The two groups of cells were differentiated into endoderm cells with 100 ng/mL Activin A and other reagents. Microarray‐based DNA methylation was analyzed with the Infinium Human Methylation450 BeadChip on these two groups. There was a significant difference in endoderm differentiation efficiency (average efficiency: 71 vs. 58.5%, P < 0.05). hESCs cultured with Activin A supplement had an increased propensity to form definitive endoderm cells in response to Activin A and Wnt signal. Differentially Methylated Regions (DMRs) between these two groups were found. DMRs were related to the stem cell maintenance and gene regulation by peroxisome proliferators via PPARα, indicating that hESCs maintained with Activin A supplement had stronger “stemness.”
Michael Addition of N‐Unprotected 2‐Oxindoles to Nitrostyrene Catalyzed by Bifunctional Tertiary Amines: Crucial Role of Dispersion Interactions
Authors: Reiter Christoph , López‐Molina Sònia , Schmid Bernhard , Neiss Christian , Görling Andreas , Tsogoeva Svetlana B.
Published: March 2014

Bifunctional thiourea‐ or sulfonamide‐derived tertiary amines catalyze the enantioselective nitro‐Michael addition of N‐unprotected 3‐substituted 2‐oxindoles to nitrostyrene in up to 99 % yields, 94:6 er, and 87:13 dr. Overcoming the necessity to introduce and remove activating or protecting groups at the nitrogen moiety leads to a reduction of energy use, costs, and waste. Transition‐state geometries for the formation of all possible stereoisomers in the nitro‐Michael addition of N‐unprotected 3‐substituted 2‐oxindole to nitrostyrene catalyzed by Takemoto’s tertiary amine–thiourea are calculated. It is shown that the relative positions and binding patterns of the reactants and the catalyst molecule are largely determined by van der Waals interactions.
Ethylene Polymerization Catalyzed by Pyrene‐Tagged Iron Complexes: The Positive Effect of π‐Conjugation and Immobilization on Multiwalled Carbon Nanotubes
Authors: Zhang Liping , Zhang Wenjuan , Serp Philippe , Sun Wen‐Hua , Durand Jérôme
Published: March 2014

2‐[1‐(2,6‐Diisopropylphenylimino)ethyl]‐6‐[1‐(pyren‐1‐ylimino)ethyl]pyridine (L1) and 2,6‐bis[1‐(pyren‐1‐ylimino)ethyl]pyridine (L2) were synthesized and used to prepare the corresponding Fe complexes Fe1 and Fe2 from FeCl2. All new compounds were characterized, and single‐crystal XRD analysis of Fe1 was performed. The π‐conjugated pyrenyl substituent enhanced the catalytic activity of the Fe complexes, which display high activity in ethylene polymerization up to 107 gPE molFe−1 h−1 (PE=polyethylene). These Fe complexes were easily immobilized on multiwalled carbon nanotubes (MWCNTs) through noncovalent π–π interactions. The supported precatalysts showed better ethylene polymerization activity than their homogeneous counterparts to produce well‐dispersed MWCNT/PE composite materials.
Aluminum‐Doped Hafnium Oxynitride: Effect of Cation Doping on Oxygen‐Reduction‐Reaction Activity in Acid Media
Authors: Chisaka Mitsuharu , Muramoto Hirokazu
Published: March 2014

Al atoms are doped into Hf sites in HfOx nanoparticles supported on carbon black to incorporate O defects without decreasing the Hf valence. The oxygen reduction reaction activity is enhanced by the Al doping, and Al atoms are stable following the N doping into the O sites and accelerated degradation tests involving 20 000 potential cycles.
On the Importance of Decarbonylation as a Side‐Reaction in the Ruthenium‐Catalysed Dehydrogenation of Alcohols: A Combined Experimental and Density Functional Study
Authors: Sieffert Nicolas , Réocreux Romain , Lorusso Patrizia , Cole‐Hamilton David J. , Bühl Michael
Published: March 2014

We report a density functional study (B97‐D2 level) of the mechanism(s) operating in the alcohol decarbonylation that occurs as an important side‐reaction during dehydrogenation catalysed by [RuH2(H2)(PPh3)3]. By using MeOH as the substrate, three distinct pathways have been fully characterised involving either neutral tris‐ or bis‐phosphines or anionic bis‐phosphine complexes after deprotonation. α‐Agostic formaldehyde and formyl complexes are key intermediates, and the computed rate‐limiting barriers are similar between the various decarbonylation and dehydrogenation paths. The key steps have also been studied for reactions involving EtOH and iPrOH as substrates, rationalising the known resistance of the latter towards decarbonylation. Kinetic isotope effects (KIEs) were predicted computationally for all pathways and studied experimentally for one specific decarbonylation path designed to start from [RuH(OCH3)(PPh3)3]. From the good agreement between computed and experimental KIEs (observed kH/kD=4), the rate‐limiting step for methanol decarbonylation has been ascribed to the formation of the first agostic intermediate from a transient formaldehyde complex.
[RhIII(Cp*)]‐Catalyzed ortho‐Selective Direct C(sp2)H Bond Amidation/Amination of Benzoic Acids by N‐Chlorocarbamates and N‐Chloromorpholines. A Versatile Synthesis of Functionalized Anthranilic Acids
Authors: Ng Fo‐Ning , Zhou Zhongyuan , Yu Wing‐Yiu
Published: March 2014

A RhIII‐catalyzed direct ortho‐CH amidation/amination of benzoic acids with N‐chlorocarbamates/N‐chloromorpholines was achieved, giving anthranilic acids in up to 85 % yields with excellent ortho‐selectivity and functional‐group tolerance. Successful benzoic acid aminations were achieved with carbamates bearing various amide groups including NHCO2Me, NHCbz, and NHTroc (Cbz=carbobenzyloxy; Troc=trichloroethylchloroformate), as well as secondary amines, such as morpholines, piperizines, and piperidines, furnishing highly functionalized anthranilic acids. A stoichiometric reaction of a cyclometallated rhodium(III) complex of benzo[h]quinoline with a silver salt of N‐chlorocarbamate afforded an amido–rhodium(III) complex, which was isolated and structurally characterized by X‐ray crystallography. This finding confirmed that the CN bond formation results from the cross‐coupling of N‐chlorocarbamate with the aryl–rhodium(III) complex. Yet, the mechanistic details regarding the CN bond formation remain unclear; pathways involving 1,2‐aryl migration and rhodium(V)– nitrene are plausible.
Simultaneous In Situ Measurement of Oxygen Consumption and Product Formation during Oxidation of Cyclohexane
Authors: Fräulin Christine , Rinke Günter , Dittmeyer Roland , Waters Gerrit , Nilles Michael
Published: March 2014

Eine auf der Laser‐Raman‐Spektroskopie basierende, ortsaufgelöste In‐situ‐Messtechnik mit hoher Nachweisempfindlichkeit wurde entwickelt, um Flüssigphasenreaktionen unter definierten Bedingungen in einem Mikrokanalreaktor zu untersuchen. Dieses Verfahren erlaubt die gleichzeitige Messung der Konzentrationen von gelöstem molekularen Sauerstoff und Oxidationsprodukten in organischen Flüssigkeiten während der Reaktion. Es kann als neues Werkzeug für detaillierte kinetische Untersuchungen verwendet werden. Hier werden erste Ergebnisse der Untersuchungen der unkatalysierten Cyclohexanoxidation vorgestellt.
Accurate Prediction of IrH Bond Dissociation Enthalpies by Density Functional Theory Methods
Authors: Zhou Yi , Liu Dingjia , Fu Yao , Yu Haizhu , Shi Jing
Published: March 2014

The iridium hydride complexes have been extensively used in organic reactions, such as oxidation and hydrogenation reactions. In many of these reactions, the dissociation or formation of IrH bond plays an important role in determining the overall reaction rates and yields. In the present study, the accuracy of different theoretical methods for prediction of IrH bond strengths has been examined on the basis of the previously reported IrH BDEs of 17 different complexes. Comparing the performance of different DFT functionals (e.g. B3LYP, TPSS, M06), different basis sets (including the different effective core potentials (ECP) on Ir and I atoms, and the total electron basis sets on the other atoms), and different solvation models (SMD, CPCM, and IEFPCM) in solution phase single point calculations, we found that the gas‐phase calculation with TPSS/(LanL2DZ: 6‐31G(d)) method is relatively more accurate than the other gas‐phase calculation methods, and can well simulate the IrH BDEs in low‐polarity solvents (such as chlorobenzene and dichloroethane). Finally, efforts were put in analyzing the structure‐activity relationships between the ligand structure (around Ir center) and the IrH BDEs. We wish the present study could benefit future studies on the Ir‐H complexes involved organic reactions.
Batchsubmit: a high‐volume batch submission system for earthquake engineering simulation
Authors: Mohan Anup , Hacker Thomas , Rodgers Gregory P. , Islam Tanzima
Published: March 2014

Network for Earthquake Engineering Simulation (NEES) is a network of 14 earthquake engineering labs distributed across the USA. As a part of the NEES effort NEESComm operates a comprehensive cyberinfrastructure that consists of the NEEShub and the NEES Project Warehouse. NEESComm provides consistent access to several high performance computing (HPC) venues. These venues include Extreme Science and Engineering Discovery Environment, the Open Science Grid, Purdue Supercomputers, and NEEShub servers. In this paper, we describe the system we developed, batchsubmit, which allows NEES researchers to make use of all these venues through the NEEShub science gateway. Copyright © 2014 John Wiley & Sons, Ltd.
High‐Resolution Tracking of Single‐Molecule Diffusion in Membranes by Confocalized and Spatially Differentiated Fluorescence Photon Stream Recording
Authors: Sahl Steffen J. , Leutenegger Marcel , Hell Stefan W. , Eggeling Christian
Published: March 2014

The performance of a method is assessed which allows for the spatiotemporal tracking of single dye‐labeled molecules during two‐dimensional (2D) diffusional transits through the focal area of a modified confocal microscope. In addition to facilitating the observation of molecular diffusion paths at the shot‐noise limit of bright organic emitters with spatial and temporal precisions of ∼10–20 nm and <0.5 ms, respectively, the direct access to the complete stream of detected photons is beneficial for characterizing nanoscale details such as transient pausing (binding). We discuss technical aspects of this approach, along with results from its application to measuring lipid membrane dynamics in live mammalian cells. Presented topics include a discussion of the advantages of the single‐photon collection mode and instrument as well as computational considerations for the localization process. A proof‐of‐principle experiment shows that optical nanoscopy by stochastic single‐molecule switching and position readout could be implementable in parallel with such fast molecular tracking. This would allow direct access to contextual imaging data of local cytoskeletal structural elements or localized longer‐lived protein assemblies.
Solution‐Processed Mesoscopic Bi2S3:Polymer Photoactive Layers
Authors: MacLachlan Andrew J. , O'Mahony Flannan T. F. , Sudlow Anna L. , Hill Michael S. , Molloy Kieran C. , Nelson Jenny , Haque Saif A.
Published: March 2014

The fabrication of solution‐processed nontoxic mesoporous Bi2S3 structures is demonstrated and the suitability of these structures for use in hybrid solar cells investigated. Mesoporous Bi2S3 electrodes are prepared via thermal decomposition of a thin film composed of a bismuth xanthate single source precursor. The resultant Bi2S3 films are made up of regular needles with approximate dimensions of 50×500 nm, as confirmed by scanning electron microscopy (SEM). The crystallinity of the Bi2S3 is found to be dependent on the annealing temperature, as determined by X‐ray diffraction. The porous Bi2S3 films are infiltrated with the hole conductor P3HT to generate novel hybrid films, and laser‐based transient absorption spectroscopy is used to interrogate the charge‐separation reaction at the resulting Bi2S3/P3HT heterojunction. Specifically, optical excitation of the hybrid films results in efficient and long‐lived charge separation (microsecond to millisecond timescale), thereby rendering such films suitable for the development of novel low‐cost solar‐energy conversion devices.
Enhancement of thermoelectric efficiency in vapor deposited Sb2Te3 and Sb1.8In0.2Te3 crystals
Authors: Thankamma G. , Kunjomana A. G.
Published: March 2014

Pure and indium doped antimony telluride (Sb2Te3) crystals find applications in high performance room temperature thermoelectric devices. Owing to the meagre physical properties exhibited on the cleavage faces of melt grown samples, an attempt was made to explore the thermoelectric parameters of p‐type crystals grown by the physical vapor deposition (PVD) method. The crystal structure of the grown platelets (9 mm× 8 mm× 2 mm) was identified as rhombohedral by x‐ray powder diffraction method. The energy dispersive analysis confirmed the elemental composition of the crystals. The electron microscopic and scanning probe image studies revealed that the crystals were grown by layer growth mechanism with low surface roughness. At room temperature (300 K), the values of Seebeck coefficient S (⊥ c) and power factor were observed to be higher for Sb1.8In0.2Te3 crystals (155 μVK−1, 2.669 × 10−3 W/mK2) than those of pure ones. Upon doping, the thermal conductivity κ (⊥ c) was decreased by 37.14% and thus thermoelectric efficiency was improved. The increased figure of merit, Z = 1.23 × 10−3 K−1 for vapour grown Sb1.8In0.2Te3 platelets indicates that it could be used as a potential thermoelectric candidate.