bluuebunny/crossref_metadata_2025 huggingface dataset:
Induction of apoptosis by cyclobutanones and derived polycyclic γ-lactones: a preliminary analysis of antiproliferative activity
Authors: Sharma Vishal , Chaudhary Ashun , Chashoo Gousia , Arora Saroj , Saxena Ajit K. , Ishar Mohan Paul S.
Published: August 2015

A series of cyclobutanones (7a–f) were synthesized by irradiation of β-ionone derived chalcones (4a–f) in aqueous methanol and further converted to polycyclic γ-lactones (8a–f) by Baeyer–Villiger oxidation.
Bottom-up synthesis of high-performance nitrogen-enriched transition metal/graphene oxygen reduction electrocatalysts both in alkaline and acidic solution
Authors: Lai Qingxue , Gao Qingwen , Su Qi , Liang Yanyu , Wang Yuxi , Yang Zhi
Published: August 2015

A versatile bottom-up protocol towards the synthesis of N–TM/G oxygen reduction electrocatalysts with a strongly-coupled triple junction structure is demonstrated.
Assembly of functionalized carbocycles or N-heterocycles through a domino electrocyclization–[1,2] migration reaction sequence
Authors: Jana Navendu , Driver Tom G.
Published: August 2015

The development of processes that streamline the synthesis of complex, functionalized carbocycles and heterocycles remains a hotly pursued topic because their scaffolds are present in a range of bioactive molecules and electronic materials.
One probe, two-channel imaging of nuclear and cytosolic compartments with orange and red emissive dyes
Authors: Pitter Demar R. G. , Brown Adrienne S. , Baker James D. , Wilson James N.
Published: August 2015

Several new DNA-targeting probes that exhibit binding-induced ‘turn on’ fluorescence are presented.
Branched alkyl ester side chains rendering large polycyclic (3E,7E)-3,7-bis(2-oxoindolin-3-ylidene)benzo[1,2-b:4,5-b′]difuran-2,6(3H,7H)-dione (IBDF) based donor–acceptor polymers solution-processability for organic thin film transistors
Authors: He Yinghui , Guo Chang , Sun Bin , Quinn Jesse , Li Yuning
Published: August 2015

We report a new type of branched alkyl ester solubilising side chain for IBDF-based donor–acceptor polymers to achieve good processability and high device performance in OTFTs.
Fast and facile one-step synthesis of monodisperse thermo-responsive core–shell microspheres and applications
Authors: Tan Jianbo , Yu Mingguang , Rao Xin , Yang Jianwen , Zeng Zhaohua
Published: August 2015

Highly monodisperse PMMA microspheres covered with a thermo-responsive shell were synthesized in a single step by means of photoinitiated RAFT dispersion polymerization at room temperature.
High strength chitosan rod prepared via LiOH/urea solvent through centrifugation induced orientation processing
Authors: Nie Jingyi , Wang Zhengke , Zhang Jiazhen , Yang Ling , Pang Yichuan , Hu Qiaoling
Published: August 2015

High strength chitosan rod prepared via LiOH/urea solvent utilizing the unique centrifugation induced orientation method.
Assembly of Fe3O4 nanoparticles on PEG-functionalized graphene oxide for efficient magnetic imaging and drug delivery
Authors: Chen Weihong , Wen Xin , Zhen Guorong , Zheng Xiuwen
Published: August 2015

We have developed a strategy for preparation of Fe3O4–PEG–GO/DOX nanocomposites for efficient magnetic imaging and drug delivery.
Superhydrophobic modification of PVDF–SiO2 electrospun nanofiber membranes for vacuum membrane distillation
Authors: Dong Zhe-Qin , Ma Xiao-Hua , Xu Zhen-Liang , Gu Zhi-Yun
Published: August 2015

Superhydrophobic nanofiber membranes with high permeate fluxes and anti-wetting properties were prepared by hydrophobic modification of PVDF–SiO2 nanofiber membranes.
N,2-Dibromo-6-chloro-3,4-dihydro-2H-benzo[e][1,2,4]thiadiazine-7-sulfonamide 1,1-dioxide: an efficient and homogeneous catalyst for one-pot synthesis of 4H-pyran, pyranopyrazole and pyrazolo[1,2-b]phthalazine derivatives under aqueous media
Authors: Khazaei Ardeshir , Zolfigol Mohammad Ali , Karimitabar Fatemeh , Nikokar Iraj , Moosavi-Zare Ahmad Reza
Published: August 2015

DCDBTSD was successfully applied in the synthesis of 4H-pyran, pyranopyrazole and pyrazolo[1,2-b]phthalazine derivatives by a one-pot multi-component reaction in water.
Bacterial assisted treatment of anaerobically digested distillery wastewater
Authors: Sankaran K. , Pisharody Lakshmi , Suriya Narayanan G. , Premalatha M.
Published: August 2015

Treatment of ADSW with culture rich inPseudomonassp. resulting benefits such as improved physico-chemical characteristics; biomass availability for energy generation; easy operation of subsequent downstream units of effluent treatment plant.
Mitigation of layer to spinel conversion of a lithium-rich layered oxide cathode by substitution of Al in a lithium ion battery
Authors: Wang Chih-Chieh , Lin Yi-Chen , Chou Po-Hsun
Published: August 2015

The layer to spinel structure conversion of lithium-rich layered oxides during cycling could be alleviated by equal substitution of Al for Mn and Ni, resulting in better capacity retention and average voltage.
Singlet oxygen generation under NIR light and visible light excitations of photosensitizers on upconversion nanoparticle surface
Authors: Joshi Padmanabh , Ahmadov Tevhide Ozkaya , Wang Peng , Zhang Peng
Published: August 2015

Effects of beef tissue on singlet oxygen generation under both near-infrared and visible light excitations are investigated and compared.
Thermo-responsive behavior of borinic acid polymers: experimental and molecular dynamics studies
Authors: Wan Wen-Ming , Zhou Peng , Cheng Fei , Sun Xiao-Li , Lv Xin-Hu , Li Kang-Kang , Xu Hai , Sun Miao , Jäkle Frieder
Published: August 2015

Molecular dynamics studies shed light on the origins of the tunable UCST of borinic acid polymers in organic solvents containing small amounts of water.
A molecular dynamics test of the Hertz–Knudsen equation for evaporating liquids
Authors: Hołyst Robert , Litniewski Marek , Jakubczyk Daniel
Published: August 2015

The precise determination of evaporation flux from liquid surfaces gives control over evaporation-driven self-assembly in soft matter systems.
Improvement of the power conversion efficiency and long term stability of polymer solar cells by incorporation of amphiphilic Nafion doped PEDOT-PSS as a hole extraction layer
Authors: Hou Xuliang , Li Qiuxiang , Cheng Tai , Yu Lu , Wang Fuzhi , Lin Jun , Dai Songyuan , Li Yongfang , Tan Zhan'ao
Published: August 2015

An effective method to enhance the conductivity and stability of PEDOT-PSS by doping with an amphiphilic perfluorosulfonic copolymer is reported.
Efficient and low-temperature processed perovskite solar cells based on a cross-linkable hybrid interlayer
Authors: Hu Qin , Liu Yi , Li Yu , Ying Lei , Liu Tanghao , Huang Fei , Wang Shufeng , Huang Wei , Zhu Rui , Gong Qihuang
Published: August 2015

Highly efficient and low-temperature processed planar heterojunction perovskite solar cells, based on the hybrid PFN-OX:ZnO electron-selective layer, were demonstrated.
Panchromatic polymer–polymer ternary solar cells enhanced by Förster resonance energy transfer and solvent vapor annealing
Authors: Goh Tenghooi , Huang Jing-Shun , Bartolome Benjamin , Sfeir Matthew Y. , Vaisman Michelle , Lee Minjoo L. , Taylor André D.
Published: August 2015

We show that strategically adding additional light active components to form ternary solar cells can significantly improve polymer solar cells.
Twisted hexaazatrianthrylene: synthesis, optoelectronic properties and near-infrared electroluminescent heterojunctions thereof
Authors: Cortizo-Lacalle Diego , Pertegás Antonio , Martínez-Sarti Laura , Melle-Franco Manuel , Bolink Henk J. , Mateo-Alonso Aurelio
Published: August 2015

The synthesis, optoelectronic properties and near-infrared electroluminescent heterojunctions of a twisted and soluble 7,8,15,16,23,24-hexaazatrianthrylene derivative are reported.
Cholinium-based ion gels as solid electrolytes for long-term cutaneous electrophysiology
Authors: Isik Mehmet , Lonjaret Thomas , Sardon Haritz , Marcilla Rebeca , Herve Thierry , Malliaras George G. , Ismailova Esma , Mecerreyes David
Published: August 2015

Cholinium-based bio-ion gels were prepared by photopolymerization of poly(cholinium lactate methacrylate) network within cholinium lactate ionic liquid.
Four-way coupled simulations of small particles in turbulent channel flow: The effects of particle shape and Stokes number
Authors: Zhao F. , George W. K. , van Wachem B. G. M.
Published: August 2015

This paper investigates the effects of particle shape and Stokes number on the behaviour of non-spherical particles in turbulent channel flow. Although there are a number of studies concerning spherical particles in turbulent flows, most important applications occurring in process, energy, and pharmaceutical industries deal with non-spherical particles. The computation employs a unique and novel four-way coupling with the Lagrangian point-particle approach. The fluid phase at low Reynolds number (Reτ = 150) is modelled by direct numerical simulation, while particles are tracked individually. Inter-particle and particle-wall collisions are also taken into account. To explore the effects of particles on the flow turbulence, the statistics of the fluid flow such as the fluid velocity, the terms in the turbulence kinetic energy equation, the slip velocity between the two phases and velocity correlations are analysed considering ellipsoidal particles with different inertia and aspect ratio. The results of the simulations show that the turbulence is considerably attenuated, even in the very dilute regime. The reduction of the turbulence intensity is predominant near the turbulence kinetic energy peak in the near wall region, where particles preferentially accumulate. Moreover, the elongated shape of ellipsoids strengthens the turbulence attenuation. In simulations with ellipsoidal particles, the fluid-particle interactions strongly depend on the orientation of the ellipsoids. In the near wall region, ellipsoids tend to align predominantly within the streamwise (x) and wall-normal (y) planes and perpendicular to the span-wise direction, whereas no preferential orientation in the central region of the channel is observed. Important conclusions from this work include the effective viscosity of the flow is not affected, the direct dissipation by the particles is negligible, and the primary mechanism by which the particles affect the flow is by altering the turbulence structure around the turbulence kinetic energy peak.
Avalanche photodiode based time-of-flight mass spectrometry
Authors: Ogasawara Keiichi , Livi Stefano A. , Desai Mihir I. , Ebert Robert W. , McComas David J. , Walther Brandon C.
Published: August 2015

This study reports on the performance of Avalanche Photodiodes (APDs) as a timing detector for ion Time-of-Flight (TOF) mass spectroscopy. We found that the fast signal carrier speed in a reach-through type APD enables an extremely short timescale response with a mass or energy independent <2 ns rise time for <200 keV ions (1−40 AMU) under proper bias voltage operations. When combined with a microchannel plate to detect start electron signals from an ultra-thin carbon foil, the APD comprises a novel TOF system that successfully operates with a <0.8 ns intrinsic timing resolution even using commercial off-the-shelf constant-fraction discriminators. By replacing conventional total-energy detectors in the TOF-Energy system, APDs offer significant power and mass savings or an anti-coincidence background rejection capability in future space instrumentation.
Optimizing the position resolution of a Z-stack microchannel plate resistive anode detector for low intensity signals
Authors: Wiggins B. B. , Richardson E. , Siwal D. , Hudan S. , deSouza R. T.
Published: August 2015

A method for achieving good position resolution of low-intensity electron signals using a microchannel plate resistive anode detector is demonstrated. Electron events at a rate of 7 counts s−1 are detected using a Z-stack microchannel plate. The dependence of position resolution on both the distance and the potential difference between the microchannel plate and resistive anode is investigated. Using standard commercial electronics, a measured position resolution of 170 μm (FWHM) is obtained, which corresponds to an intrinsic resolution of 157 μm (FWHM).
Two-dimensional spatiotemporal focusing of femtosecond pulses and its applications in microscopy
Authors: Song Qiyuan , Nakamura Aoi , Hirosawa Kenichi , Isobe Keisuke , Midorikawa Katsumi , Kannari Fumihiko
Published: August 2015

We demonstrate and theoretically analyze the two-dimensional spatiotemporal focusing of femtosecond pulses by utilizing a two-dimensional spectral disperser. Compared with spatiotemporal focusing with a diffraction grating, it can achieve widefield illumination with better sectioning ability for a multiphoton excitation process. By utilizing paraxial approximation, our analytical method improves the axial confinement ability and identifies that the free spectra range (FSR) of the two-dimensional spectral disperser affects the out-of-focus multiphoton excitation intensity due to the temporal self-imaging effect. Based on our numerical simulation, a FSR of 50 GHz is necessary to reduce the out-of-focus two-photon excitation by 2 orders of magnitude compared with that in a grating-based spatiotemporal focusing scheme for a 90-fs excitation laser pulse. We build a two-dimensional spatiotemporal focusing microscope using a virtually imaged phased array and achieve an axial resolution of 1.3 μm, which outperforms the resolution of conventional spatiotemporal focusing using a grating by a factor of 1.7, and demonstrate better image contrast inside a tissue-like phantom.
Communication: Practical intramolecular symmetry adapted perturbation theory via Hartree-Fock embedding
Authors: Parrish Robert M. , Gonthier Jérôme F. , Corminbœuf Clémence , Sherrill C. David
Published: August 2015

We develop a simple methodology for the computation of symmetry-adapted perturbation theory (SAPT) interaction energy contributions for intramolecular noncovalent interactions. In this approach, the local occupied orbitals of the total Hartree-Fock (HF) wavefunction are used to partition the fully interacting system into three chemically identifiable units: the noncovalent fragments A and B and a covalent linker C. Once these units are identified, the noninteracting HF wavefunctions of the fragments A and B are separately optimized while embedded in the HF wavefunction of C, providing the dressed zeroth order wavefunctions for A and B in the presence of C. Standard two-body SAPT (particularly SAPT0) is then applied between the relaxed wavefunctions for A and B. This intramolecular SAPT procedure is found to be remarkably straightforward and efficient, as evidenced by example applications ranging from diols to hexaphenyl-ethane derivatives.
Dynamics of protein aggregation and oligomer formation governed by secondary nucleation
Authors: Michaels Thomas C. T. , Lazell Hamish W. , Arosio Paolo , Knowles Tuomas P. J.
Published: August 2015

The formation of aggregates in many protein systems can be significantly accelerated by secondary nucleation, a process where existing assemblies catalyse the nucleation of new species. In particular, secondary nucleation has emerged as a central process controlling the proliferation of many filamentous protein structures, including molecular species related to diseases such as sickle cell anemia and a range of neurodegenerative conditions. Increasing evidence suggests that the physical size of protein filaments plays a key role in determining their potential for deleterious interactions with living cells, with smaller aggregates of misfolded proteins, oligomers, being particularly toxic. It is thus crucial to progress towards an understanding of the factors that control the sizes of protein aggregates. However, the influence of secondary nucleation on the time evolution of aggregate size distributions has been challenging to quantify. This difficulty originates in large part from the fact that secondary nucleation couples the dynamics of species distant in size space. Here, we approach this problem by presenting an analytical treatment of the master equation describing the growth kinetics of linear protein structures proliferating through secondary nucleation and provide closed-form expressions for the temporal evolution of the resulting aggregate size distribution. We show how the availability of analytical solutions for the full filament distribution allows us to identify the key physical parameters that control the sizes of growing protein filaments. Furthermore, we use these results to probe the dynamics of the populations of small oligomeric species as they are formed through secondary nucleation and discuss the implications of our work for understanding the factors that promote or curtail the production of these species with a potentially high deleterious biological activity.
Density-matrix based determination of low-energy model Hamiltonians from ab initio wavefunctions
Authors: Changlani Hitesh J. , Zheng Huihuo , Wagner Lucas K.
Published: August 2015

We propose a way of obtaining effective low energy Hubbard-like model Hamiltonians from ab initio quantum Monte Carlo calculations for molecular and extended systems. The Hamiltonian parameters are fit to best match the ab initio two-body density matrices and energies of the ground and excited states, and thus we refer to the method as ab initio density matrix based downfolding. For benzene (a finite system), we find good agreement with experimentally available energy gaps without using any experimental inputs. For graphene, a two dimensional solid (extended system) with periodic boundary conditions, we find the effective on-site Hubbard U∗/t to be 1.3 ± 0.2, comparable to a recent estimate based on the constrained random phase approximation. For molecules, such parameterizations enable calculation of excited states that are usually not accessible within ground state approaches. For solids, the effective Hamiltonian enables large-scale calculations using techniques designed for lattice models.
Experimental rig to estimate the coefficient of friction between tire and surface in airplane touchdown simulations
Authors: Li Chengwei , Zhan Liwei
Published: August 2015

To estimate the coefficient of friction between tire and runway surface during airplane touchdowns, we designed an experimental rig to simulate such events and to record the impact and friction forces being executed. Because of noise in the measured signals, we developed a filtering method that is based on the ensemble empirical mode decomposition and the bandwidth of probability density function of each intrinsic mode function to extract friction and impact force signals. We can quantify the coefficient of friction by calculating the maximum values of the filtered force signals. Signal measurements are recorded for different drop heights and tire rotational speeds, and the corresponding coefficient of friction is calculated. The result shows that the values of the coefficient of friction change only slightly. The random noise and experimental artifact are the major reason of the change.
Microscopic origin of temporal heterogeneities in translational dynamics of liquid water
Authors: Mukherjee Biswaroop
Published: August 2015

Liquid water is known to reorient via a combination of large angular jumps (due to exchange of hydrogen bonding (H-bond) partners) and diffusive orientations. Translation of the molecule undergoing the orientational jump and its initial and final H-bond acceptors plays a key role in the microscopic reorientation process. Here, we partition the translational dynamics into those occurring during intervals when rotating water molecules (and their initial and final H-bonding partners) undergo orientational jump and those arising when molecules wait between consecutive orientational jumps. These intervals are chosen in such a way that none of the four possible H-bonds involving the chosen water molecule undergo an exchange process within its duration. Translational dynamics is analysed in terms of the distribution of particle displacements, van Hove functions, and its moments. We observe that the translational dynamics, calculated from molecular dynamics simulations of liquid water, is fastest during the orientational jumps and slowest during periods of waiting. The translational dynamics during all temporal intervals shows an intermediate behaviour. This is the microscopic origin of temporal dynamic heterogeneity in liquid water, which is mild at 300 K and systematically increases with supercooling. Study of such partitioned dynamics in supercooled water shows increased disparity in dynamics occurring in the two different types of intervals. Nature of the distribution of particle displacements in supercooled water is investigated and it reveals signatures non-Gaussian behaviour.
Examination of the phase transition behavior of nano-confined fluids by statistical temperature molecular dynamics
Authors: Gai Lili , Iacovella Christopher R. , Wan Li , McCabe Clare , Cummings Peter T.
Published: August 2015

The fluid-solid phase transition behavior of nano-confined Lennard-Jones fluids as a function of temperature and degree of nanoconfinement has been studied via statistical temperature molecular dynamics (STMD). The STMD method allows the direct calculation of the density of states and thus the heat capacity with high efficiency. The fluids are simulated between parallel solid surfaces with varying pore sizes, wall-fluid interaction energies, and registry of the walls. The fluid-solid phase transition behavior has been characterized through determination of the heat capacity. The results show that for pores of ideal-spacing, the order-disorder transition temperature (TODT) is reduced as the pore size increases until values consistent with that seen in a bulk system. Also, as the interaction between the wall and fluid is reduced, TODT is reduced due to weak constraints from the wall. However, for non-ideal spacing pores, quite different behavior is obtained, e.g., generally TODT are largely reduced, and TODT is decreased as the wall constraint becomes larger. For unaligned walls (i.e., whose lattices are not in registry), the fluid-solid transition is also detected as T is reduced, indicating non-ideality in orientation of the walls does not impact the formation of a solid, but results in a slight change in TODT compared to the perfectly aligned systems. The STMD method is demonstrated to be a robust way for probing the phase transitions of nanoconfined fluids systematically, enabling the future examination of the phase transition behavior of more complex fluids.
Accurate transport properties for H–CO and H–CO2
Authors: Dagdigian Paul J.
Published: August 2015

Transport properties for collisions of hydrogen atoms with CO and CO2 have been computed by means of quantum scattering calculations. The carbon oxides are important species in hydrocarbon combustion. The following potential energy surfaces (PES’s) for the interaction of the molecule fixed in its equilibrium geometry were employed: for H–CO, the PES was taken from the work of Song et al. [J. Phys. Chem. A 117, 7571 (2013)], while the PES for H–CO2 was computed in this study by a restricted coupled cluster method that included single, double, and (perturbatively) triple excitations. The computed transport properties were found to be significantly different from those computed by the conventional approach that employs isotropic Lennard-Jones (12-6) potentials. The effect of using the presently computed accurate transport properties in 1-dimensional combustion simulations of methane-air flames was investigated.
Bismuth pyrochlore thin films for dielectric energy storage
Authors: Michael Elizabeth K. , Trolier-McKinstry Susan
Published: August 2015

Thin films of cubic pyrochlore bismuth zinc niobate, bismuth zinc tantalate, and bismuth zinc niobate tantalate were fabricated using chemical solution deposition. This family of materials exhibited moderate relative permittivities between 55 ± 2 and 145 ± 5 for bismuth zinc tantalate and bismuth zinc niobate, respectively, and low loss tangents on the order of 0.0008 ± 0.0001. Increases in the concentration of the tantalum end member increased the dielectric breakdown strength. For example, at 10 kHz, the room temperature breakdown strength of bismuth zinc niobate was 5.1 MV/cm, while that of bismuth zinc tantalate was 6.1 MV/cm. This combination of a high breakdown strength and a moderate permittivity led to a high discharged energy storage density for all film compositions. For example, at a measurement frequency of 10 kHz, bismuth zinc niobate exhibited a maximum recoverable energy storage density of 60.8 ± 2.0 J/cm3, while bismuth zinc tantalate exhibited a recoverable energy storage density of 60.7 ± 2.0 J/cm3. Intermediate compositions of bismuth zinc niobate tantalate offered higher energy storage densities; at 10 mol. % tantalum, the maximum recoverable energy storage density was ∼66.9 ± 2.4 J/cm3.
One-step preparation of transparent superhydrophobic coatings using atmospheric arc discharge
Authors: Li Jian , Huang Zhengyong , Wang Feipeng , Yan Xinzhu , Wei Yuan
Published: August 2015

In this letter, we report a fast, simple, and single step approach to the preparation of transparent super-hydrophobic coatings on a copper conductor via atmosphere pressure arc discharges. The preparation procedures, hydrophobic characteristics, anti-pollution capability, and transparency of the super-hydrophobic coating are presented. A dual micro- and nano-scale hierarchical structure is observed on the super-hydrophobic coating with a water contact angle greater than 150°. The coating is, thus, capable of removing a significant amount of contaminants with a small quantity of water droplets. Attenuated total reflection Fourier transform infrared spectroscopy indicates that hydrophobic methyl groups exist on the surface of the coating. The surface roughness measurement results prove that the super-hydrophobic surface obeys the Cassie-Baxter model and its light scattering is very weak. Results demonstrate the conceptual feasibility of production of optically transparent super-hydrophobic coating by arc spraying of polymers under the atmospheric pressure.
Electroelastic fields in artificially created vortex cores in epitaxial BiFeO3 thin films
Authors: Winchester B. , Balke N. , Cheng X. X. , Morozovska A. N. , Kalinin S. , Chen L. Q.
Published: August 2015

We employ phase-field modeling to explore the elastic properties of artificially created 1-D domain walls in (001)p-oriented BiFeO3 thin films, composed of a junction of the four polarization variants, all with the same out-of-plane polarization. It was found that these junctions exhibit peculiarly high electroelastic fields induced by the neighboring ferroelastic/ferroelectric domains. The vortex core exhibits a volume expansion, while the anti-vortex core is more compressive. Possible ways to control the electroelastic field, such as varying material constant and applying transverse electric field, are also discussed.
Communication: The simplified generalized entropy theory of glass-formation in polymer melts
Authors: Freed Karl F.
Published: August 2015

While a wide range of non-trivial predictions of the generalized entropy theory (GET) of glass-formation in polymer melts agree with a large number of observed universal and non-universal properties of these glass-formers and even for the dependence of these properties on monomer molecular structure, the huge mathematical complexity of the theory precludes its extension to describe, for instance, the perplexing, complex behavior observed for technologically important polymer films with thickness below ∼100 nm and for which a fundamental molecular theory is lacking for the structural relaxation. The present communication describes a hugely simplified version of the theory, called the simplified generalized entropy theory (SGET) that provides one component necessary for devising a theory for the structural relaxation of thin polymer films and thereby supplements the first required ingredient, the recently developed Flory-Huggins level theory for the thermodynamic properties of thin polymer films, before the concluding third step of combining all the components into the SGET for thin polymer films. Comparisons between the predictions of the SGET and the full GET for the four characteristic temperatures of glass-formation provide good agreement for a highly non-trivial model system of polymer melts with chains of the structure of poly(n-α olefins) systems where the GET has produced good agreement with experiment. The comparisons consider values of the relative backbone and side group stiffnesses such that the glass transition temperature decreases as the amount of excess free volume diminishes, contrary to general expectations but in accord with observations for poly(n-alkyl methacrylates). Moreover, the SGET is sufficiently concise to enable its discussion in a standard course on statistical mechanics or polymer physics.
GEANT4 simulations for beam emittance in a linear collider based on plasma wakefield acceleration
Authors: Mete O. , Labiche M. , Xia G. , Hanahoe K.
Published: August 2015

Alternative acceleration technologies are currently under development for cost-effective, robust, compact, and efficient solutions. One such technology is plasma wakefield acceleration, driven by either a charged particle or laser beam. However, the potential issues must be studied in detail. In this paper, the emittance evolution of a witness beam through elastic scattering from gaseous media and under transverse focusing wakefields is studied.
Fluorescently tuned nitrogen-doped carbon dots from carbon source with different content of carboxyl groups
Authors: Wang Hao , Gao Peng , Wang Yun , Guo Jun , Zhang Ke-Qin , Du Dezhuang , Dai Xiao , Zou Guifu
Published: August 2015

In this study, fluorescent nitrogen-doped carbon dots (NCDs) were tuned via varying the sources with different number of carboxyl groups. Owing to the interaction between amino and carboxyl, more amino groups conjugate the surface of the NCDs by the source with more carboxyl groups. Fluorescent NCDs were tuned via varying the sources with different content of carboxyl groups. Correspondingly, the nitrogen content, fluorescence quantum yields and lifetime of NCDs increases with the content of carboxyl groups from the source. Furthermore, cytotoxicity assay and cell imaging test indicate that the resultant NCDs possess low cytotoxicity and excellent biocompatibility.
Low field colossal anisotropic magnetoresistance in spatially confined electronically phase separated La0.3Pr0.4Ca0.3MnO3 microbridges
Authors: Jeon J. , Alagoz H. S. , Jung J. , Chow K. H.
Published: August 2015

Colossal in-plane anisotropic magnetoresistance (AMR) of >16 000% has been engineered in spatially confined La0.3Pr0.4Ca0.3MnO3 films. Recalling that typical AMR values in films are only a few percent, these results mark an astonishing increase that might potentially lead to fabrication of manganite-based switching and sensor devices. The unique colossal behavior is discussed within the context of anisotropic domain growth.
The influence of sodium on the molybdenum/Cu(In,Ga)Se2 interface recombination velocity, determined by time resolved photoluminescence
Authors: Jarzembowski Enrico , Syrowatka Frank , Kaufmann Kai , Fränzel Wolfgang , Hölscher Torsten , Scheer Roland
Published: August 2015

In this work, glass/diffusion barrier/Mo/Cu(In,Ga)Se2 stacks with and without adding NaF are investigated with the goal to determine the back surface recombination velocity. The absorber layers prepared by a three-stage co-evaporation process are characterized by time resolved photoluminescence (TRPL) and time of flight-secondary ion mass spectroscopy (TOF-SIMS). By comparison of experimental TRPL data with simulated TRPL transients calculated with Synopsys TCAD, Mo/Cu(In,Ga)Se2 interface recombination velocities for electrons of Sb,n≤1×102 cm/s (with NaF) and Sb,n≥1×105 cm/s (without NaF) are determined. SIMS analysis points towards differences in alkali metal concentrations at the back contact being the origin of different Sb,n values. Our results shine light on the large spread of experimental Sn values reported in the literature and reveal another hitherto unknown effect of alkali doping in Cu(In,Ga)Se2 semiconductors.
Optical electrical current sensor utilizing a graphene-microfiber-integrated coil resonator
Authors: Yan Shao-cheng , Zheng Bi-cai , Chen Jin-hui , Xu Fei , Lu Yan-qing
Published: August 2015

A graphene-based electrical current sensor is proposed utilizing a microfiber coil resonator. Monolayer graphene sheet with a large sheet resistance is transferred onto the surface of a glass capillary rod. A microfiber is spirally wrapped around the graphene sheet to form a coil resonator. Heat generated from electrical current shifts the resonant wavelength because of the thermal effect in the microfiber resonator. The sensor exhibits a very good performance with a high sensitivity of 67.297 μm/A2, which is two orders of magnitude higher than that reported earlier. Our results show that microfiber-graphene-integrated devices have great potential for miniature and highly sensitive fiber sensors for monitoring electrical current.
Disorder-driven phase transition in La0.37D0.30Ca0.33MnO3 (D = Bi, Sm) manganites
Authors: Ade Ramesh , Singh R.
Published: August 2015

In the present work we report the structural, electron spin resonance (ESR) and magnetic properties of La0.37D0.30Ca0.33MnO3 (D = Bi, Sm) manganites synthesized by sol-gel method. The critical behavior at the critical point, where the system undergoes phase transition from paramagnetic (PM) to ferromagnetic (FM) state, is investigated by using modified-Arrott plots, Kouvel-Fisher method and critical isotherm analysis. Both the samples show second-order phase transition near the critical point. The decrease in magnetization (M), Curie temperature (TC), evolution of spin or cluster glass behavior and the nature of second-order phase transition compared to the first-order transition reported in the literature for La0.67Ca0.33MnO3 are ascribed to disorder caused by the size mismatch of the A-site cations with Bi and Sm doping at La-site.
Precision spectroscopy comes to the mid-IR
Authors: Miller Johanna L.
Published: August 2015

Quantum cascade lasers, whose wavelengths collectively range from 3 µm to 25 µm and beyond, can now be stabilized in frequency to better than 1 part in 1014.
Behemoth telescopes build toward first light
Authors: Feder Toni
Published: August 2015

Among the science goals for three 30-m-scale telescopes is to seek signs of extraterrestrial life. But the big projects must first overcome big hurdles.
Influence of wind speed on the global variability of burned fraction: a global fire model’s perspective
Authors: Lasslop Gitta , Hantson Stijn , Kloster Silvia
Published: August 2015

Understanding of fire behaviour, especially fire spread, is mostly based on local-scale observations but the same equations are applied in global models on a much coarser scale. Most model formulations include the effect of wind speed with a positive influence on fire spread. Availability of global datasets offers new possibilities to evaluate these approaches based on local-scale observations at the global scale. Here, we analyse the relation between wind speed derived from three datasets and remotely sensed burned fraction (burned area divided by grid cell area) on a climate model grid scale. The bivariate relationship between burned fraction and wind speed is characterised by an initial increase in burned fraction and a decrease in burned fraction for wind speeds higher than 2–3 ms–1. In a multivariate analysis we additionally included the effect of tree cover, precipitation or atmospheric moisture, temperature, vegetation net primary productivity and population density on burned fraction. This analysis confirmed the lack of an increase in burned fraction for high wind speeds on annual and daily time scale. From the observation-based analysis we conclude that a positive response of burned fraction for high wind speed should not be applied in coarse-scale global fire models.
Measuring and mitigating agricultural greenhouse gas production in the US Great Plains, 1870–2000
Authors: Parton William J. , Gutmann Myron P. , Merchant Emily R. , Hartman Melannie D. , Adler Paul R. , McNeal Frederick M. , Lutz Susan M.
Published: August 2015

Significance

The US Great Plains is an agricultural production center for the global market and a source of greenhouse gas (GHG) emissions. This article uses historical data and ecosystem models to estimate the magnitude of annual GHG fluxes from all agricultural sources (cropping, livestock, irrigation, fertilizer production, and tractor use) from 1870 to 2000. Carbon (C) emissions from plow-out of native grasslands peaked in the 1930s and were the largest agricultural source of GHG emissions at the time. Soil C emissions subsequently declined, whereas GHG fluxes from other activities increased. The results inform knowledge about the relationship between agriculture and its environmental setting and show that available alternative management practices could substantially mitigate the environmental consequences of agricultural activities without reducing food production.
Oxidative cyclizations in orthosomycin biosynthesis expand the known chemistry of an oxygenase superfamily
Authors: McCulloch Kathryn M. , McCranie Emilianne K. , Smith Jarrod A. , Sarwar Maruf , Mathieu Jeannette L. , Gitschlag Bryan L. , Du Yu , Bachmann Brian O. , Iverson T. M.
Published: August 2015

Significance

Bacterial resistance to clinically relevant antibiotics has renewed public interest in identifying therapeutics with new scaffolds for the treatment of such infections. Analogs of orthosomycins could provide one such scaffold. One route to modifying these scaffolds is through rational engineering of the biosynthetic enzymes, requiring characterization of the biosynthetic pathway. A key feature of orthosomycin antibiotics is the orthoester linkage between carbohydrate groups, and our data suggest that a family of oxygenases is likely responsible for orthoester formation.
Rhythmicity of the intestinal microbiota is regulated by gender and the host circadian clock
Authors: Liang Xue , Bushman Frederic D. , FitzGerald Garret A.
Published: August 2015

Significance

Recent studies of the murine microbiome have revealed circadian behavior and linked it to host feeding time, but the mechanism responsible for rhythmicity has not been fully clarified. Here we report that both the host circadian system and host gender influence the rhythmicity of the total load and taxonomic abundances in the fecal microbiota, and that regulation by the host clock is dominant. Disruption of the host circadian clock by deletion of
Bmal1
altered the fecal microbial composition in a gender-dependent fashion. Our analyses suggest the need to consider circadian factors and host gender in the design of microbiome studies, and highlight the importance of analyzing absolute abundance in understanding the microbiota.
MTMR3
risk allele enhances innate receptor-induced signaling and cytokines by decreasing autophagy and increasing caspase-1 activation
Authors: Lahiri Amit , Hedl Matija , Abraham Clara
Published: August 2015

Significance

This study describes a previously undefined role for myotubularin-related protein 3 (MTMR3) in modulating pattern recognition receptor (PRR)-induced responses and identifies mechanisms mediating these outcomes in primary human macrophages. It further defines that
MTMR3
in the inflammatory bowel disease risk
MTMR3/HORMAD2/LIF/OSM
locus accounts for the genotype-dependent regulation of PRR-initiated outcomes in macrophages. Our studies highlight mechanisms whereby MTMR3 may contribute to intestinal inflammation, specifically both by inhibiting autophagy and by enhancing signaling and cytokine secretion upon stimulation of a broad range of PRRs.
Changing central Pacific El Niños reduce stability of North American salmon survival rates
Authors: Kilduff D. Patrick , Di Lorenzo Emanuele , Botsford Louis W. , Teo Steven L. H.
Published: August 2015

Significance

Historically, many Pacific salmon species were thought to be influenced by the Pacific Decadal Oscillation (PDO), an indicator of ocean conditions, associated with El Niños. As the nature of El Niños has changed recently, another ocean indicator, the North Pacific Gyre Oscillation (NPGO) has become more important. By comparing time series, we find that coho and Chinook salmon survival rates along the west coast of North America are more strongly connected to the NPGO than the PDO. This was accompanied by increased similarity in survival rates of both species. Society seeks to maintain biodiversity among ecosystem components to provide a stable supply of ecosystem services through a portfolio effect. Increasingly similar salmon survivals implies reduced stability of these ecosystem services.
Spin-liquid polymorphism in a correlated electron system on the threshold of superconductivity
Authors: Zaliznyak Igor , Savici Andrei T. , Lumsden Mark , Tsvelik Alexei , Hu Rongwei , Petrovic Cedomir
Published: August 2015

Significance

Liquid polymorphism and liquid–liquid phase transformations are remarkable phenomena of great fundamental and practical interest, as is unconventional superconductivity. Yet, despite being intensely studied, they still remain enigmatic. Our results not only provide a rare experimental example of liquid polymorphism, which occurs in the spin system of an iron chalcogenide superconductor, but also establish its unexpected connection with the onset of unconventional superconductivity.
Flourishing ocean drives the end-Permian marine mass extinction
Authors: Schobben Martin , Stebbins Alan , Ghaderi Abbas , Strauss Harald , Korn Dieter , Korte Christoph
Published: August 2015

Significance

This study provides geochemical evidence that links some of the most important finds associated with the end-Permian mass extinction, including climate warming, enhanced weathering, increased primary productivity, and widespread marine anoxia under a common denominator: the linked biogeochemical sulfur and carbon cycles. Lethal marine conditions are likely the result of climate feedback mechanisms acting to increase nutrient input to the ocean, thereby stimulating global organic carbon production. With future projected climate change in mind, such climate feedback mechanisms could induce widespread eutrophication and expansion of anoxic and sulfidic zones, thereby fundamentally altering marine ecosystems.
Creative template-dependent synthesis by human polymerase mu
Authors: Moon Andrea F. , Gosavi Rajendrakumar A. , Kunkel Thomas A. , Pedersen Lars C. , Bebenek Katarzyna
Published: August 2015

Significance

Template-dependent DNA polymerases usually add nucleotides to the 3ʹ end of a primer, using the first available template-strand nucleotide as a guide. This behavior holds true for all polymerases, except one, DNA polymerase μ. When presented with 2-nt single- or double-strand gaps, polymerase μ (Pol μ) engages the substrate with the last available template-strand nucleotide closest to the 5′-phosphate on the downstream end of the gap, guiding synthesis. Crystal structures of Pol μ with a 2-nt gapped DNA substrate explain how the unpaired base is accommodated in the active site, and yield insights into the behavior of this polymerase within the context of nonhomologous end joining in DNA double-strand break repair.
Crowded growth leads to the spontaneous evolution of semistable coexistence in laboratory yeast populations
Authors: Frenkel Evgeni M. , McDonald Michael J. , Van Dyken J. David , Kosheleva Katya , Lang Gregory I. , Desai Michael M.
Published: August 2015

Significance

The spontaneous emergence of stable coexistence between competing lineages in experimental evolution illustrates principles behind the creation and maintenance of biodiversity. Here, we present the first experimental observation of a general mechanism that leads to stable diversification in microbial populations despite competition for shared resources. Coexistence in our system depends on a tradeoff between growth and the ability to avoid cellular crowding. We elucidate the biophysical and genetic basis of this coexistence, and introduce a mathematical model that explains our results. Our analysis demonstrates that this coexistence can be perturbed by evolution on longer time scales, providing a unique quantitative example of how the interactions between ecological and evolutionary processes can create and destroy diversity in microbial populations.
Flow perfusion effects on three-dimensional culture and drug sensitivity of Ewing sarcoma
Authors: Santoro Marco , Lamhamedi-Cherradi Salah-Eddine , Menegaz Brian A. , Ludwig Joseph A. , Mikos Antonios G.
Published: August 2015

Significance

Most preclinical drug screening systems fail to predict whether a given drug candidate will succeed in clinical trials due to the fact that cells are plated on culture dishes devoid of signaling cues present in vivo. Among other factors, biomechanical stimulation strongly affects tumor behavior. Toward this end, we cultured Ewing sarcoma cells on 3D scaffolds within a flow perfusion bioreactor, which provides mechanical stimulation in the form of flow-derived shear stress. Cells exposed to flow perfusion produced more insulin-like growth factor-1 (IGF-1) ligand and showed shear stress-dependent sensitivity to IGF-1 receptor targeted drugs when compared with static conditions. Collectively, this research provides an improved method to study cancer cells ex vivo and could narrow the gap between preclinical and clinical drug activity.
Ablation of XP-V gene causes adipose tissue senescence and metabolic abnormalities
Authors: Chen Yih-Wen , Harris Robert A. , Hatahet Zafer , Chou Kai-ming
Published: August 2015

Significance

The metabolic syndrome has evolved to be a major health issue globally. The association between genome integrity and metabolic abnormalities is not well understood. Our results indicate that increased DNA damage and persistent activation of the DNA damage response induce adipocyte senescence in DNA polymerase η knockout (
pol
η
−/−
) mice. Suppression of adipocyte senescence with a p53 inhibitor, pifithrin-α, alleviated metabolic abnormalities in
pol η
−/−
mice. An increase or decrease in DNA damage affected the senescence status of adipocytes accordingly, which was also in concordance with the severity of metabolic abnormalities in the
pol η
−/−
mice. Our current results indicate that reduced genome integrity plays a causative role in provoking adipocyte senescence that leads to development of obesity and insulin resistance.
Switching of perpendicularly polarized nanomagnets with spin orbit torque without an external magnetic field by engineering a tilted anisotropy
Authors: You Long , Lee OukJae , Bhowmik Debanjan , Labanowski Dominic , Hong Jeongmin , Bokor Jeffrey , Salahuddin Sayeef
Published: August 2015

Significance

When a spin orbit torque is applied to a magnet with perpendicular anisotropy, the induced spin accumulation is completely symmetric with respect to the magnetization. As a result, a deterministic switching cannot be achieved unless an external magnetic field is applied to break the symmetry. Here, we show that, by engineering a tilted anisotropy in a magnetic nanodot, the symmetry can effectively be broken and a deterministic switching of perpendicular magnetization can be achieved without needing the external magnetic field. These results are significant for the field of spintronics as the symmetry breaking provides new insight into the physics of spin orbit torque and the switching without a magnetic field could lead to significant impact in high-density storage applications.