bluuebunny/crossref_metadata_2025 huggingface dataset:
The unexpected flexibility of natural cellulose at a single-chain level and its implications to the design of nano materials
Authors: Bao Yu , Qian Hu-Jun , Lu Zhong-Yuan , Cui Shuxun
Published: September 2014

Single-chain mechanical measurements reveal that natural cellulose is as flexible as common synthetic polymers at the single-chain level.
Synthesis of enantiomerically enriched indolines and tetrahydroisoquinolines from (S)-amino acid-derived chiral carbocations: an easy access to (3S,4R)-demethoxy-3-isopropyl diclofensine
Authors: Manna Sudipta Kumar , Panda Gautam
Published: September 2014

Enantiomerically enriched indolines and tetrahydroisoquinolines were synthesized in high yields from easily accessible (S)-amino acid-derived chiral carbocations.
Exploiting nucleobase-containing materials – from monomers to complex morphologies using RAFT dispersion polymerization
Authors: Kang Yan , Pitto-Barry Anaïs , Willcock Helen , Quan Wen-Dong , Kirby Nigel , Sanchez Ana M. , O'Reilly Rachel K.
Published: September 2014

The synthesis of nucleobase-containing polymers was successfully performed by RAFT dispersion polymerization in both chloroform and 1,4-dioxane and self-assembly was induced by the polymerizations.
A smart and rapid colorimetric method for the detection of codeine sulphate, using unmodified gold nanoprobe
Authors: Lodha Anand , Pandya Alok , Sutariya Pinkesh G. , Menon Shobhana K.
Published: September 2014

Herein, we reported unique optical and electrochemical properties of citrate-stabilized gold nanoparticles (AuNPs) as a probe for smartphone-assisted, on-spot detection of codeine sulphate in toxicological screening with high sensitivity (0.9 μM).
Blending of cellulolytic enzyme preparations from different fungal sources for improved cellulose hydrolysis by increasing synergism
Authors: Adsul Mukund , Sharma Bhawna , Singhania Reeta Rani , Saini Jitendra Kumar , Sharma Ankita , Mathur Anshu , Gupta Ravi , Tuli Deepak Kumar
Published: September 2014

A prepared enzyme cocktail from different fungal enzyme preparations increases the hydrolysis of avicel/wheat straw by increasing synergism between the same or different types of cellulases.
The edge termination controlled kinetics in graphene chemical vapor deposition growth
Authors: Shu Haibo , Chen Xiaoshuang , Ding Feng
Published: September 2014

The kinetics of graphene CVD growth is dominated by the type of edge passivation.
A surfactant-modulated fluorescent sensor with pattern recognition capability: sensing and discriminating multiple heavy metal ions in aqueous solution
Authors: Cao Yuan , Ding Liping , Hu Wenting , Peng Junxia , Fang Yu
Published: September 2014

Surfactant aggregates modulating the cross-reactive responses of bispyrene fluorophore containing hydrophilic spacer for the pattern recognition of multiple heavy metal ions.
In situ fabrication of three-dimensional, ultrathin graphite/carbon nanotube/NiO composite as binder-free electrode for high-performance energy storage
Authors: Liu Wenwen , Lu Congxiang , Wang Xingli , Liang Kun , Tay Beng Kang
Published: September 2014

3D ultrathin graphite film/CNTs/NiO composite as the electrode material for energy storage exhibits high specific capacitance/capacity, excellent rate capability and good cycle stability.
A gold nanopopcorn attached single-walled carbon nanotube hybrid for rapid detection and killing of bacteria
Authors: Ondera Thomas J. , Hamme II Ashton T.
Published: September 2014

Antibody conjugated gold nanopopcorn attached SWCNT hybrid nanomaterials possess great potential for selective label-free detection and photothermal killing of bacteria.
Photo- and thermal switching of blue phase films reflecting both right- and left-circularly polarized light
Authors: Guo Jinbao , Wang Jiao , Zhang Junyan , Shi Yang , Wang Xinwei , Wei Jie
Published: September 2014

A new kind of blue phase (BP) liquid crystal (LC) films which could reflect both right- and left-circularly polarized light and photo- and thermal switching performance has been demonstrated.
Multi‐UAV‐based stereo vision system without GPS for ground obstacle mapping to assist path planning of UGV
Authors: Kim Jin Hyo , Kwon Ji‐Wook , Seo Jiwon
Published: September 2014

A multi‐unmanned aerial vehicle (UAV)‐based stereo vision system is proposed to assist global path planning of an unmanned ground vehicle (UGV) even in GPS‐denied environments. The proposed system can optimally generate the depth map of ground objects and robustly detect obstacles. The proposed multi‐UAV‐based system with a movable baseline overcomes the limitations of a single‐UAV‐based stereo vision system with a fixed baseline. Thus, the performance of the proposed system does not degrade significantly based on the altitude of UAVs. The relative position and altitude estimation, multi‐agent formation control and image processing techniques are considered to implement a prototype system. The experimental results demonstrate the performance of the implemented system for various baseline conditions between UAVs.
IEEE 802.11‐enabled wake‐up radio system: design and performance evaluation
Authors: Oller J. , Garcia E. , Lopez E. , Demirkol I. , Casademont J. , Paradells J. , Gamm U. , Reindl L.
Published: September 2014

Today, the vast majority of personal communication devices, such as laptops, smartphones, and logically wireless fidelity (Wi‐Fi) access points feature IEEE 802.11 chipsets. In turn, wake‐up radio (WuR) systems are used to reduce the significant energy waste that wireless devices cause during their idle communication mode. A novel WuR system is introduced that enables any IEEE 802.11‐enabled device to be used as a WuR transmitter without requiring any hardware modification. The corresponding developed WuR receiver achieves a remarkably low power consumption of 10.8 μW and operates in the Wi‐Fi 2.4 GHz band. By means of thorough physical tests, it is shown that the proposed IEEE 802.11‐based WuR system enables important energy savings.
Analysis of the methods for the derivation of binary kinetic equations in the theory of fluorescence concentration quenching
Authors: Doktorov A. B.
Published: September 2014

In the framework of unified many-particle approach the familiar problem of fluorescence concentration quenching in the presence of pumping (light pulse) of arbitrary intensity is considered. This process is a vivid and the simplest example of multistage bulk reaction including bimolecular irreversible quenching reaction and reversible monomolecular transformation as elementary stages. General relation between the kinetics of multistage bulk reaction and that of the elementary stage of quenching has been established. This allows one to derive general kinetic equations (of two types) for the multistage reaction in question on the basis of general kinetic equations (differential and integro-differential) of elementary stage of quenching. Relying on the same unified many-particle approach we have developed binary approximations with the use of two (frequently employed in the literature) many-particle methods (such as simple superposition approximation and the method of extracting pair channels in three-particle correlation evolution) to the derivation of non-Markovian binary kinetic equations. The possibility of reducing the obtained binary equations to the Markovian equations of formal chemical kinetics has been considered. As an example the exact solution of the problem (for the specific case) is examined, and the applicability of two many particle methods of derivation of binary equations is analyzed.
Potential and flux field landscape theory. II. Non-equilibrium thermodynamics of spatially inhomogeneous stochastic dynamical systems
Authors: Wu Wei , Wang Jin
Published: September 2014

We have established a general non-equilibrium thermodynamic formalism consistently applicable to both spatially homogeneous and, more importantly, spatially inhomogeneous systems, governed by the Langevin and Fokker-Planck stochastic dynamics with multiple state transition mechanisms, using the potential-flux landscape framework as a bridge connecting stochastic dynamics with non-equilibrium thermodynamics. A set of non-equilibrium thermodynamic equations, quantifying the relations of the non-equilibrium entropy, entropy flow, entropy production, and other thermodynamic quantities, together with their specific expressions, is constructed from a set of dynamical decomposition equations associated with the potential-flux landscape framework. The flux velocity plays a pivotal role on both the dynamic and thermodynamic levels. On the dynamic level, it represents a dynamic force breaking detailed balance, entailing the dynamical decomposition equations. On the thermodynamic level, it represents a thermodynamic force generating entropy production, manifested in the non-equilibrium thermodynamic equations. The Ornstein-Uhlenbeck process and more specific examples, the spatial stochastic neuronal model, in particular, are studied to test and illustrate the general theory. This theoretical framework is particularly suitable to study the non-equilibrium (thermo)dynamics of spatially inhomogeneous systems abundant in nature. This paper is the second of a series.
Simple physics of the partly pinned fluid systems
Authors: Krakoviack Vincent
Published: September 2014

In this paper, we consider some aspects of the physics of the partly pinned (PP) systems obtained by freezing in place particles in equilibrium bulk fluid configurations in the normal (nonglassy) state. We first discuss the configurational overlap and the disconnected density correlation functions, both in the homogeneous and heterogeneous cases, using the tools of the theory of adsorption in disordered porous solids. The relevant Ornstein-Zernike equations are derived, and asymptotic results valid in the regime where the perturbation due to the pinning process is small are obtained. Second, we consider the homogeneous PP lattice gas as a means to make contact between pinning processes in particle and spin systems and show that it can be straightforwardly mapped onto a random field Ising model with a strongly asymmetric bimodal distribution of the field. Possible implications of these results for studies of the glass transition based on PP systems are also discussed.
Vibrational spectra and structures of bare and Xe-tagged cationic SinOm+ clusters
Authors: Savoca Marco , Langer Judith , Harding Dan J. , Palagin Dennis , Reuter Karsten , Dopfer Otto , Fielicke André
Published: September 2014

Vibrational spectra of Xe-tagged cationic silicon oxide clusters SinOm+ with n = 3–5 and m = n, n ± 1 in the gas phase are obtained by resonant infrared multiple photon dissociation (IRMPD) spectroscopy and density functional theory calculations. The SinOm+ clusters are produced in a laser vaporization ion source and Xe complexes are formed after thermalization to 100 K. The clusters are subsequently irradiated with tunable light from an IR free electron laser and changes in the mass distribution yield size-specific IR spectra. The measured IRMPD spectra are compared to calculated linear IR absorption spectra leading to structural assignments. For several clusters, Xe complexation alters the energetic order of the SinOm+ isomers. Common structural motifs include the Si2O2 rhombus, the Si3O2 pentagon, and the Si3O3 hexagon.
Equations of state of ice VI and ice VII at high pressure and high temperature
Authors: Bezacier Lucile , Journaux Baptiste , Perrillat Jean-Philippe , Cardon Hervé , Hanfland Michael , Daniel Isabelle
Published: September 2014

High-pressure H2O polymorphs among which ice VI and ice VII are abundant in the interiors of large icy satellites and exo-planets. Knowledge of the elastic properties of these pure H2O ices at high-temperature and high-pressure is thus crucial to decipher the internal structure of icy bodies. In this study we assess for the first time the pressure-volume-temperature (PVT) relations of both polycrystalline pure ice VI and ice VII at high pressures and temperatures from 1 to 9 GPa and 300 to 450 K, respectively, by using in situ synchrotron X-ray diffraction. The PVT data are adjusted to a second-order Birch-Murnaghan equation of state and give V0 = 14.17(2) cm3 mol−1, K0 = 14.05(23) GPa, and α0 = 14.6(14) × 10−5 K−1 for ice VI and V0 = 12.49(1) cm3 mol−1, K0 = 20.15(16) GPa, and α0 = 11.6(5) × 10−5 K−1 for ice VII.
Thermoelectric characteristic of the rough InN/GaN core-shell nanowires
Authors: Wu Chao-Wei , Wu Yuh-Renn
Published: September 2014

An analysis to model the thermoelectric (TE) effects of the rough InN/GaN core-shell nanowires (NWs) with wire diameter ranging from 25 nm to 100 nm is proposed. The elastic continuum model is employed to calculate the phonon dispersion relation curves and the related phonon group velocity. Within the framework of Boltzmann transport equations and relaxation time approximation, the electrical conductivity, Seebeck coefficient, electronic thermal conductivity, and the lattice thermal conductivity is obtained. Simulation results indicate that TE properties of the rough InN/GaN core-shell NWs are strongly affected by the surface roughness and the diameter of NWs. The optimized condition of the proposed rough InN/GaN core-shell TE NWs is studied in this paper and the highest ZT obtained in the calculation is 0.8598 at 300 K and 1.713 at 1000 K.
Testing time-dependent density functional theory with depopulated molecular orbitals for predicting electronic excitation energies of valence, Rydberg, and charge-transfer states and potential energies near a conical intersection
Authors: Li Shaohong L. , Truhlar Donald G.
Published: September 2014

Kohn-Sham (KS) time-dependent density functional theory (TDDFT) with most exchange-correlation functionals is well known to systematically underestimate the excitation energies of Rydberg and charge-transfer excited states of atomic and molecular systems. To improve the description of Rydberg states within the KS TDDFT framework, Gaiduk et al. [Phys. Rev. Lett. 108, 253005 (2012)] proposed a scheme that may be called HOMO depopulation. In this study, we tested this scheme on an extensive dataset of valence and Rydberg excitation energies of various atoms, ions, and molecules. It is also tested on a charge-transfer excitation of NH3-F2 and on the potential energy curves of NH3 near a conical intersection. We found that the method can indeed significantly improve the accuracy of predicted Rydberg excitation energies while preserving reasonable accuracy for valence excitation energies. However, it does not appear to improve the description of charge-transfer excitations that are severely underestimated by standard KS TDDFT with conventional exchange-correlation functionals, nor does it perform appreciably better than standard TDDFT for the calculation of potential energy surfaces.
Preparation of gallium nitride surfaces for atomic layer deposition of aluminum oxide
Authors: Kerr A. J. , Chagarov E. , Gu S. , Kaufman-Osborn T. , Madisetti S. , Wu J. , Asbeck P. M. , Oktyabrsky S. , Kummel A. C.
Published: September 2014

A combined wet and dry cleaning process for GaN(0001) has been investigated with XPS and DFT-MD modeling to determine the molecular-level mechanisms for cleaning and the subsequent nucleation of gate oxide atomic layer deposition (ALD). In situ XPS studies show that for the wet sulfur treatment on GaN(0001), sulfur desorbs at room temperature in vacuum prior to gate oxide deposition. Angle resolved depth profiling XPS post-ALD deposition shows that the a-Al2O3 gate oxide bonds directly to the GaN substrate leaving both the gallium surface atoms and the oxide interfacial atoms with XPS chemical shifts consistent with bulk-like charge. These results are in agreement with DFT calculations that predict the oxide/GaN(0001) interface will have bulk-like charges and a low density of band gap states. This passivation is consistent with the oxide restoring the surface gallium atoms to tetrahedral bonding by eliminating the gallium empty dangling bonds on bulk terminated GaN(0001).
Structure and strain relaxation effects of defects in InxGa1−xN epilayers
Authors: Rhode S. L. , Fu W. Y. , Moram M. A. , Massabuau F. C.-P. , Kappers M. J. , McAleese C. , Oehler F. , Humphreys C. J. , Dusane R. O. , Sahonta S.–L.
Published: September 2014

The formation of trench defects is observed in 160 nm-thick InxGa1−xN epilayers with x ≤ 0.20, grown on GaN on (0001) sapphire substrates using metalorganic vapour phase epitaxy. The trench defect density increases with increasing indium content, and high resolution transmission electron microscopy shows an identical structure to those observed previously in InGaN quantum wells, comprising meandering stacking mismatch boundaries connected to an I1-type basal plane stacking fault. These defects do not appear to relieve in-plane compressive strain. Other horizontal sub-interface defects are also observed within the GaN pseudosubstrate layer of these samples and are found to be pre-existing threading dislocations which form half-loops by bending into the basal plane, and not basal plane stacking faults, as previously reported by other groups. The origins of these defects are discussed and are likely to originate from a combination of the small in-plane misorientation of the sapphire substrate and the thermal mismatch strain between the GaN and InGaN layers grown at different temperatures.
Anomalous skin effects in a weakly magnetized degenerate electron plasma
Authors: Abbas G. , Sarfraz M. , Shah H. A.
Published: September 2014

Fully relativistic analysis of anomalous skin effects for parallel propagating waves in a weakly magnetized degenerate electron plasma is presented and a graphical comparison is made with the results obtained using relativistic Maxwellian distribution function [G. Abbas, M. F. Bashir, and G. Murtaza, Phys. Plasmas 18, 102115 (2011)]. It is found that the penetration depth for R- and L-waves for degenerate case is qualitatively small in comparison with the Maxwellian plasma case. The quantitative reduction due to weak magnetic field in the skin depth in R-wave for degenerate plasma is large as compared to the non-degenerate one. By ignoring the ambient magnetic field, previous results for degenerate field free case are salvaged [A. F. Alexandrov, A. S. Bogdankevich, and A. A. Rukhadze, Principles of Plasma Electrodynamics (Springer-Verlag, Berlin/Heidelberg, 1984), p. 90].
Low energy electron induced cytosine base release in 2′-deoxycytidine-3′-monophosphate via glycosidic bond cleavage: A time-dependent wavepacket study
Authors: Bhaskaran Renjith , Sarma Manabendra
Published: September 2014

Low energy electron (LEE) induced cytosine base release in a selected pyrimidine nucleotide, viz., 2′-deoxycytidine-3′-monophosphate is investigated using ab initio electronic structure methods and time dependent quantum mechanical calculations. It has been noted that the cytosine base scission is comparatively difficult process than the 3′ C–O bond cleavage from the lowest π* shape resonance in energy region <1 eV. This is mainly due to the high activation energy barrier associated with the electron transfer from the π* orbital of the base to the σ* orbital of the glycosidic N–C bond. In addition, the metastable state formed after impinging LEE (0–1 eV) has very short lifetime (10 fs) which may decay in either of the two competing auto-detachment or dissociation process simultaneously. On the other hand, the selected N–C mode may cleave to form the cytosine base anion at higher energy regions (>2 eV) via tunneling of the glycosidic bond. Resonance states generated within this energy regime will exist for a duration of ∼35–55 fs. Comparison of salient features of the two dissociation events, i.e., 3′ C–O single strand break and glycosidic N–C bond cleavage in 3′-dCMPH molecule are also provided.
Physical origins of the high structural stability of CLN025 with only ten residues
Authors: Yasuda Satoshi , Hayashi Tomohiko , Kinoshita Masahiro
Published: September 2014

CLN025, a peptide with only 10 residues, folds into a specific β-hairpin structure (this is referred to as “native structure”). Here we investigate the stabilization mechanism for CLN025 using our free-energy function F. F comprises two components, the hydration entropy and the component related to the energetic dehydration effect. The former component is calculated using the hybrid of the angle-dependent integral equation theory (ADIET) and our recently developed morphometric approach. The ADIET is a statistical-mechanical theory applied to a molecular model for water. The latter component is calculated in a simple but judicious manner accounting for physically the most important factors: the break of polypeptide-water hydrogen bonds and formation of polypeptide intramolecular hydrogen bonds upon structural change to a more compact one. We consider the native structure, compact nonnative structures newly generated, and a set of random coils mimicking the unfolded state. F and its components are calculated for all the structures considered. The loss of the polypeptide conformational entropy upon structural transition from the unfolded state to a compact structure is also estimated using a simple but physically reasonable manner. We find that the key factor is the water-entropy gain upon folding originating primarily from an increase in the total volume available to the translational displacement of water molecules in the system, which is followed by the reduction of water crowding. The amino-acid sequence of CLN025 enables it not only to closely pack the backbone and side chains including those with large aromatic groups but also to assure the intramolecular hydrogen bonding upon burial of a donor and an acceptor when the backbone forms the native structure. The assurance leads to essentially no enthalpy increase upon folding. The close packing brings a water-entropy gain which is large enough to surpass the conformational-entropy loss. By contrast, it is not possible for the design template of CLN025, GPM12, to realize the same type of structure formation. There are significantly many compact structures which are equally stable in terms of F, and due to the conformational-entropy effect, the unfolded state is favorably stabilized.
Valence and ionic lowest-lying electronic states of ethyl formate as studied by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy, and ab initio calculations
Authors: Śmiałek M. A. , Łabuda M. , Guthmuller J. , Hubin-Franskin M.-J. , Delwiche J. , Duflot D. , Mason N. J. , Hoffmann S. V. , Jones N. C. , Limão-Vieira P.
Published: September 2014

The highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C2H5OCHO, yet reported is presented over the wavelength range 115.0–275.5 nm (10.75–4.5 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of ethyl formate and are compared with a newly recorded He(I) photoelectron spectrum (from 10.1 to 16.1 eV). New vibrational structure is observed in the first photoelectron band. The photoabsorption cross sections have been used to calculate the photolysis lifetime of ethyl formate in the upper stratosphere (20–50 km).
Capillary wave dynamics of thin liquid polymer films
Authors: Lin Fan-Yen , Steffen Werner
Published: September 2014

The dynamics of thin, liquid polybutadiene films on solid substrates at temperatures far above the glass transition temperature Tg was studied by Resonance Enhanced Dynamic Light Scattering. The capillary wave dynamics is the stronger suppressed by the substrate the thinner the film. We find a molecular weight independent film-thickness below which the dynamics change dramatically—the viscosity increases by orders of magnitude. This change is not related to 3Rg as postulated in theory and claimed in some experimental findings but rather to a fixed distance from the solid interface. Part of our observations we attribute to a, compared to bulk polymer, less mobile viscoelastic layer adjacent to the substrate, and part to a more mobile layer at the liquid-gas interface. Thus, the overall behavior of the dynamics can be explained by a “three layer” model, the third layer having bulk behavior in between the above two layers.
Influence of the chemical surface structure on the nanoscale friction in plasma nitrided and post-oxidized ferrous alloy
Authors: Freislebem Márcia , Menezes Caren M. , Cemin Felipe , Costi Fernanda B. , Ferreira Patrícia A. , Aguzzoli César , Baumvol Israel J. R. , Alvarez Fernando , Figueroa Carlos A.
Published: September 2014

Friction is a ubiquitous phenomenon in everyday activities spanning from vehicles where efficient brakes are mandatory up to mechanical devices where its minimum effects are pursued for energy efficiency issues. Recently, theoretical models succeed correlating the friction behavior with energy transference via phonons between sliding surfaces. Therefore, considering that the energy losses by friction are prompted through phonons, the chemical surface structure between sliding surfaces is very important to determine the friction phenomenon. In this work, we address the issue of friction between a conical diamond tip sliding on different functionalized flat steel surfaces by focusing the influence of the chemical bonds in the outermost layers on the sliding resistance. This geometry allows probing the coupling of the sharp tip with terminator species on the top and underneath material surface at in-depth friction measurements from 20 to 200 nm. Experimentally, the friction coefficient decreases when nitrogen atoms are substituted for oxygen in the iron network. This effect is interpreted as due to energy losses through phonons whilst lower vibrational frequency excitation modes imply lower friction coefficients and a more accurate adjustment is obtained when a theoretical model with longitudinal adsorbate vibration is used.
High-resolution tangential absolute extreme ultraviolet arrays for radiated power density measurements on NSTX-U
Authors: Delgado-Aparicio L. , Bell R. E. , Faust I. , Tritz K. , Diallo A. , Gerhardt S. P. , Kozub T. A. , LeBlanc B. P. , Stratton B. C.
Published: September 2014

The radiated-power-density diagnostic on the equatorial midplane for the NSTX-U tokamak will be upgraded to measure the radial structure of the photon emissivity profile with an improved radial resolution. This diagnostic will enhance the characterization and studies of power balance, impurity transport, and MHD. The layout and response expected of the new system is shown for different plasma conditions and impurity concentrations. The effect of toroidal rotation driving poloidal asymmetries in the core radiation from high-Z impurities is also addressed.
A diabatic state model for double proton transfer in hydrogen bonded complexes
Authors: McKenzie Ross H.
Published: September 2014

Four diabatic states are used to construct a simple model for double proton transfer in hydrogen bonded complexes. Key parameters in the model are the proton donor-acceptor separation R and the ratio, D1/D2, between the proton affinity of a donor with one and two protons. Depending on the values of these two parameters the model describes four qualitatively different ground state potential energy surfaces, having zero, one, two, or four saddle points. Only for the latter are there four stable tautomers. In the limit D2 = D1 the model reduces to two decoupled hydrogen bonds. As R decreases a transition can occur from a synchronous concerted to an asynchronous concerted to a sequential mechanism for double proton transfer.
Spreading of droplet with insoluble surfactant on corrugated topography
Authors: Li Chunxi , Pei Jianjun , Ye Xuemin
Published: September 2014

The flow of microscale fluid on a topography surface is a key to further development of MEMS, nanoscience and technology. In the present paper, a theoretical model of the droplet spreading with insoluble surfactant over corrugated topography is established with the lubrication theory, and the evolution equations of film thickness and surfactant concentration in base state and disturbance state are formulated. The droplet dynamics, the nonlinear stability based on nonmodal stability theory, and the effects of topography structure and Marangoni stress are numerically simulated with PDECOL scheme. Results show that the impact of topographical surface is strengthened apparently while the Marangoni stress driven by surfactant concentration is weakened in the mid-late stages of the spreading. The droplet radius on the topography advances faster and the lowest height of liquid/gas interface near the droplet edge reduces remarkably in the intermediate stage compared with those on the flat wall. The quantity of the wavelet similar to the topography increases gradually, with the characteristics of wavelet crest height with time exhibiting a single-hump feature. The spreading stability is enhanced under the disturbance wavenumber of 4, however, is to deteriorate and even to transform into instability when wavenumber increases further. In addition, the reductive Marangoni number, enhancive capillary number, modest Peclet number, the low height of the topography as well as small wavenumber of topography can make contributions to the evident stability of droplet spreading.
Comparative study of dynamics in glass forming mixtures of Debye-type N-ethylacetamide with water, alcohol, and amine
Authors: Li Xin , Chen Zeming , Li Zijing , Gao Yanqin , Tu Wenkang , Li Xiangqian , Zhang Yaqi , Liu Ying Dan , Wang Li-Min
Published: September 2014

The glass transition and relaxation dynamics in the binary mixtures of a Debye liquid, N-ethylacetamide, with water, monoalcohol, and amine are studied by calorimetric and dielectric measurements in the highly viscous regimes near the glass transition. Calorimetric measurements show the glass transition temperature in the N-ethylacetamide–water mixtures is remarkably enhanced as water is added as high as 70 mol. % before crystallization is detected. A similar increase is also observed in the N-ethylacetamide-rich mixtures with the non-Debye 1,2-propanediamine. However, the dielectric measurements show that the main relaxation in the N-ethylacetamide–water mixtures with water fraction up to 60 mol. % reproduces the dynamic characters of the mixtures constituted by two Debye liquids, N-ethylacetamide and 2-ethyl-1-butanol. The comparison of the calorimetric and dielectric features for the three mixing systems suggests that the Debye relaxation persists in the N-ethylacetamide–water mixtures within the experimentally studied compositions.
Communication: Supramolecular structures in monohydroxy alcohols: Insights from shear-mechanical studies of a systematic series of octanol structural isomers
Authors: Hecksher Tina , Jakobsen Bo
Published: September 2014

A recent study [C. Gainaru, R. Figuli, T. Hecksher, B. Jakobsen, J. C. Dyre, M. Wilhelm, and R. Böhmer, Phys. Rev. Lett. 112, 098301 (2014)] of two supercooled monohydroxy alcohols close to the glass-transition temperature showed that the Debye peak, thus far mainly observed in the electrical response, also has a mechanical signature. In this work, we apply broadband shear-mechanical spectroscopy to a systematic series of octanol structural isomers, x-methyl-3-heptanol (with x ranging from 2 to 6). We find that the characteristics of the mechanical signature overall follow the systematic behavior observed in dielectric spectroscopy. However, the influence from the molecular structure is strikingly small in mechanics (compared to roughly a factor 100 increase in dielectric strength) and one isomer clearly does not conform to the general ordering. Finally, the mechanical data surprisingly indicate that the size of the supramolecular structures responsible for the Debye process is nearly unchanged in the series.
Premelting, fluctuations, and coarse-graining of water-ice interfaces
Authors: Limmer David T. , Chandler David
Published: September 2014

Using statistical field theory supplemented with molecular dynamics simulations, we consider premelting on the surface of ice as a generic consequence of broken hydrogen bonds at the boundary between the condensed and gaseous phases. A procedure for coarse-graining molecular configurations onto a continuous scalar order parameter field is discussed, which provides a convenient representation of the interface between locally crystal-like and locally liquid-like regions. A number of interfacial properties are straightforwardly evaluated using this procedure such as the average premelting thickness and surface tension. The temperature and system size dependence of the premelting layer thickness calculated in this way confirms the characteristic logarithmic growth expected for the scalar field theory that the system is mapped onto through coarse-graining, though remains finite due to long-ranged interactions. Finally, from explicit simulations the existence of a premelting layer is shown to be insensitive to bulk lattice geometry, exposed crystal face, and curvature.
Low-frequency vortex oscillation around slender bodies at high angles-of-attack
Authors: Ma Bao-Feng , Liu Tong-Xin
Published: September 2014

Low-frequency unsteadiness of vortices over an ogive-cylinder body was studied using numerical simulation and Dynamic Mode Decomposition (DMD). The results revealed that the vortices over the fore-body of the slender body can exhibit vortex oscillation with a non-dimensional frequency of 0.054 at 70° angle-of-attack, but the flow pattern over the aft-body downstream is Kármán vortex shedding. The vortex oscillation induces larger sectional side-forces on the body than vortex shedding. The DMD analysis for the sectional flow fields at various sections shows that the most energetic mode corresponds to the vortex oscillation at the fore-body and the vortex shedding at the aft-body except the mode for a mean flow, and the associated frequencies are identical to the ones of the sectional side-forces obtained by Fourier transformation.
Shear bands in metallic glasses are not necessarily hot
Authors: Slaughter Stephanie K. , Kertis Felicitee , Deda Erin , Gu Xiaojun , Wright Wendelin J. , Hufnagel T. C.
Published: September 2014

We have used the fusible tin coating method to detect shear band heating in amorphous Zr57Ti5Cu20Ni8Al10 loaded under quasi-static uniaxial compression. High-rate load data allowed a precise determination of the duration of shearing events and final fracture. When loading was halted prior to fracture we saw no evidence of melted tin despite the presence of shear offsets up to 6 μm on some shear bands. Samples loaded to fracture showed evidence of tin melting near the fracture surface. We attribute the difference to the duration of the events, which is much longer for shear banding (milliseconds) than for fracture (microseconds).
Further reduction of efficiency droop effect by adding a lower-index dielectric interlayer in a surface plasmon coupled blue light-emitting diode with surface metal nanoparticles
Authors: Lin Chun-Han , Su Chia-Ying , Kuo Yang , Chen Chung-Hui , Yao Yu-Feng , Shih Pei-Ying , Chen Horng-Shyang , Hsieh Chieh , Kiang Yean-Woei , Yang C. C.
Published: September 2014

Further reduction of the efficiency droop effect and further enhancements of internal quantum efficiency (IQE) and output intensity of a surface plasmon coupled, blue-emitting light-emitting diode (LED) by inserting a dielectric interlayer (DI) of a lower refractive index between p-GaN and surface Ag nanoparticles are demonstrated. The insertion of a DI leads to a blue shift of the localized surface plasmon (LSP) resonance spectrum and increases the LSP coupling strength at the quantum well emitting wavelength in the blue range. With SiO2 as the DI, a thinner DI leads to a stronger LSP coupling effect, when compared with the case of a thicker DI. By using GaZnO, which is a dielectric in the optical range and a good conductor under direct-current operation, as the DI, the LSP coupling results in the highest IQE, highest LED output intensity, and weakest droop effect.
Characterizing the dielectric properties of human mesenchymal stem cells and the effects of charged elastin-like polypeptide copolymer treatment
Authors: Adams T. N. G. , Turner P. A. , Janorkar A. V. , Zhao F. , Minerick A. R.
Published: September 2014

Human mesenchymal stem cells (hMSCs) have three key properties that make them desirable for stem cell therapeutics: differentiation capacity, trophic activity, and ability to self-renew. However, current separation techniques are inefficient, time consuming, expensive, and, in some cases, alter hMSCs cellular function and viability. Dielectrophoresis (DEP) is a technique that uses alternating current electric fields to spatially separate biological cells based on the dielectric properties of their membrane and cytoplasm. This work implements the first steps toward the development of a continuous cell sorting microfluidic device by characterizing native hMSCs dielectric signatures and comparing them to hMSCs morphologically standardized with a polymer. A quadrapole Ti-Au electrode microdevice was used to observe hMSC DEP behaviors, and quantify frequency spectra and cross-over frequency of hMSCs from 0.010–35 MHz in dextrose buffer solutions (0.030 S/m and 0.10 S/m). This combined approach included a systematic parametric study to fit a core-shell model to the DEP spectra over the entire tested frequency range, adding robustness to the analysis technique. The membrane capacitance and permittivity were found to be 2.2 pF and 2.0 in 0.030 S/m and 4.5 pF and 4.1 in 0.10 S/m, respectively. Elastin-like polypeptide (ELP-) polyethyleneimine (PEI) copolymer was used to control hMSCs morphology to spheroidal cells and aggregates. Results demonstrated that ELP-PEI treatment controlled hMSCs morphology, increased experiment reproducibility, and concurrently increased hMSCs membrane permittivity to shift the cross-over frequency above 35 MHz. Therefore, ELP-PEI treatment may serve as a tool for the eventual determination of biosurface marker-dependent DEP signatures and hMSCs purification.
Nonlinear optical and magnetic properties of BiFeO3 harmonic nanoparticles
Authors: Schwung Sebastian , Rogov Andrii , Clarke Gareth , Joulaud Cécile , Magouroux Thibaud , Staedler Davide , Passemard Solène , Jüstel Thomas , Badie Laurent , Galez Christine , Wolf Jean Pierre , Volkov Yuri , Prina-Mello Adriele , Gerber-Lemaire Sandrine , Rytz Daniel , Mugnier Yannick , Bonacina Luigi , Le Dantec Ronan
Published: September 2014

Second Harmonic Generation (SHG) from BiFeO3 nanocrystals is investigated for the first time to determine their potential as biomarkers for multiphoton imaging. Nanocrystals are produced by an auto-combustion method with 2-amino-2-hydroxymethyl-propane-1,3-diol as a fuel. Stable colloidal suspensions with mean particle diameters in the range 100–120 nm are then obtained after wet-milling and sonication steps. SHG properties are determined using two complementary experimental techniques, Hyper Rayleigh Scattering and nonlinear polarization microscopy. BiFeO3 shows a very high second harmonic efficiency with an averaged 〈d〉 coefficient of 79 ± 12 pm/V. From the nonlinear polarization response of individual nanocrystals, relative values of the independent dij coefficients are also determined and compared with recent theoretical and experimental studies. Additionally, the particles show a moderate magnetic response, which is attributed to γ-Fe2O3 impurities. A combination of high nonlinear optical efficiency and magnetic response within the same particle is of great interest for future bio-imaging and diagnostic applications.
Strain mediated coupling in magnetron sputtered multiferroic PZT/Ni-Mn-In/Si thin film heterostructure
Authors: Singh Kirandeep , Singh Sushil Kumar , Kaur Davinder
Published: September 2014

The strain mediated electrical and magnetic properties were investigated in PZT/Ni-Mn-In heterostructure deposited on Si (100) by dc/rf magnetron sputtering. X-ray diffraction pattern revealed that (220) orientation of Ni-Mn-In facilitate the (110) oriented tertragonal phase growth of PZT layer in PZT/Ni-Mn-In heterostructure. A distinctive peak in dielectric constant versus temperature plots around martensitic phase transformation temperature of Ni-Mn-In showed a strain mediated coupling between Ni-Mn-In and PZT layers. The ferroelectric measurement taken at different temperatures exhibits a well saturated and temperature dependent P-E loops with a highest value of Psat ∼ 55 μC/cm2 obtained during martensite-austenite transition temperature region of Ni-Mn-In. The stress induced by Ni-Mn-In layer on upper PZT film due to structural transformation from martensite to austenite resulted in temperature modulated Tunability of PZT/Ni-Mn-In heterostructure. A tunability of 42% was achieved at 290 K (structural transition region of Ni-Mn-In) in these heterostructures. I-V measurements taken at different temperatures indicated that ohmic conduction was the main conduction mechanism over a large electric field range in these heterostructures. Magnetic measurement revealed that heterostructure was ferromagnetic at room temperature with a saturation magnetization of ∼123 emu/cm3. Such multiferroic heterostructures exhibits promising applications in various microelectromechanical systems.
The Elusive Johann Joseph Oppel (1815–1894)
Authors: Phillips David , Wade Nicholas J
Published: September 2014

Oppel is frequently cited for coining the term ‘geometrical optical illusions’ in 1855, but portrayals of him have rarely been sighted. We present a portrait of him and a brief description of his contributions to the study of illusions as well as other areas of sound and vision, particularly stereoscopy, colour, and motion. Despite the citations in the context of illusions, Oppel remains an elusive figure in the history of science.
The movement pattern of horses around race meetings in New Zealand
Authors: Rosanowski S. M. , Rogers C. W. , Bolwell C. F. , Cogger N.
Published: September 2014

In order to describe the implications of racehorse movement on the potential spread and control of infectious disease in New Zealand, the movement of horses due to regular racing activities needed to be quantified. Race meeting, trainer and starter data were collected in 2009 from the governing bodies for the two racing codes in New Zealand; Harness Racing New Zealand and New Zealand Thoroughbred Racing. During 2009, 507 Thoroughbred and 506 Standardbred race meetings were held. A random selection of 42 Standardbred and 39 Thoroughbred race meetings were taken from all race meetings held in 2009 and the distances travelled by trainers to these race meetings were determined. The trainers attending selected race meetings represented 50% (1135/2287) of all registered trainers in 2009. There was no seasonal pattern of when race meetings were held between racing codes (P = 0.18) or by race type (P = 0.83). There were significant differences in the distance travelled by trainers to race meetings, by racing code (P < 0.001). Thoroughbred trainers travelled a median of 91 km (IQR 40–203 km), while Standardbred trainers travelled a median of 45 km (IQR 24–113 km) (P < 0.001). Within each racing code, trainers travelled further to attend premier races than other types of race meetings (P < 0.001). These data demonstrate there is higher potential for more widespread disease dissemination from premier race meetings compared with other types of race meetings. Additionally, lack of a seasonal pattern indicates that a widespread outbreak could occur at any time of the year. Widespread disease dissemination would increase the logistic effort required for effective infectious disease control and has the potential to increase the time required to achieve control.
Discovery of human posterior head 20 (hPH20) and homo sapiens sperm acrosome associated 1 (hSPACA1) immunocontraceptive epitopes and their effects on fertility in male and female mice
Authors: Chen Xuemei , Liu Xiaodong , Ren Xiuhua , Li Xuewu , Wang Li , Zang Weidong
Published: September 2014

The key goals of immunocontraception research are to obtain full contraceptive effects using vaccines administered to both males and females. Current research concerning human anti-sperm contraceptive vaccines is focused on delineating infertility-related epitopes to avoid autoimmune disease. We constructed phage-display peptide libraries to select epitope peptides derived from human posterior head 20 (hPH20) and homo sapiens sperm acrosome associated 1 (hSPACA1) using sera collected from infertile women harbouring anti-sperm antibodies. Following five rounds of selection, positive colonies were reconfirmed for reactivity with the immunoinfertile sera. We biopanned and analysed the chemical properties of four epitope peptides, named P82, Sa6, Sa37 and Sa76. Synthetic peptides were made and coupled to either bovine serum albumin (BSA) or ovalbumin. We used the BSA-conjugated peptides to immunise BALB/c mice and examined the effects on fertility in female and male mice. The synthetic peptides generated a sperm-specific antibody response in female and male mice that caused a contraceptive state. The immunocontraceptive effect was reversible and, with the disappearance of peptide-specific antibodies, there was complete restoration of fertility. Vaccinations using P82, Sa6 and Sa76 peptides resulted in no apparent side effects. Thus, it is efficient and practical to identify epitope peptide candidates by phage display. These peptides may find clinical application in the specific diagnosis and treatment of male and female infertility and contraceptive vaccine development.
The effects of permeating cryoprotectants on intracellular free-calcium concentrations and developmental potential of in vitro-matured feline oocytes
Authors: Herrick Jason R. , Wang Chunmin , Machaty Zoltan
Published: September 2014

Embryos produced from vitrified feline oocytes have resulted in pregnancies, but the efficiency of oocyte vitrification in cats is still low. Our objectives were to evaluate the effects of exposing feline oocytes to ethylene glycol (EG), propanediol (PrOH) and dimethyl sulfoxide (DMSO) on changes in intracellular free-calcium concentrations ([Ca2+]i), the time needed for enzymatic digestion of the zona pellucida (ZP), the incidence of parthenogenetic activation and degeneration and embryonic development following in vitro fertilisation (IVF). All of the chemicals tested altered [Ca2+]i, but changes in [Ca2+]i, resistance of the ZP to enzymatic digestion and the incidence of parthenogenetic activation (<5% for all treatments) were not affected (P > 0.05) by extracellular Ca2+. Exposure to EG (>44.1%) and DMSO (19.7%) increased (P < 0.05) oocyte degeneration compared with control oocytes and oocytes exposed to PrOH (≤2.5%). Following exposure to a combination of PrOH and DMSO (10% v/v each), blastocyst development (per cleaved embryo; 52.1%) was similar (P > 0.05) to control oocytes (64.4%). When oocytes were vitrified with PrOH and DMSO, 28.3% of surviving (intact plasma membrane) oocytes cleaved following IVF, but no blastocyst developed. When a non-permeating cryoprotectant (galactose, 0.25 M) was added to the vitrification medium, 47.7% of surviving oocytes cleaved and 14.3% developed to the blastocyst stage.