bluuebunny/crossref_metadata_2025 huggingface dataset:
Preservation of DNA in nuclease-rich samples using magnetic ionic liquids
Authors: Clark Kevin D. , Sorensen Matthew , Nacham Omprakash , Anderson Jared L.
Published: April 2016

Magnetic ionic liquids (MIL) can serve as DNA preservation media in nuclease-rich environments. Plasmid DNA exhibited structural stability for up to 1 week in MILs.
W-shaped liquid crystalline dimers
Authors: Horčic Martin , Svoboda Jiří , Seidler Arnošt , Kozmík Václav , Novotná Vladimíra , Pociecha Damian , Gorecka Ewa
Published: April 2016

We present a study of liquid crystalline bent-core dimers with a novel W-shaped molecular structure exhibiting broad polymorphism.
Core cross-linked micelles of polyphosphoester containing amphiphilic block copolymers as drug nanocarriers
Authors: Yilmaz Z. Ergul , Vanslambrouck S. , Cajot S. , Thiry J. , Debuigne A. , Lecomte P. , Jérôme C. , Riva R.
Published: April 2016

Poly(ethylene oxide)-b-polyphosphoester bearing unsaturations are promising materials for drug delivery applications.
Co nanoparticles embedded in a 3D CoO matrix for electrocatalytic hydrogen evolution
Authors: Liu Xiangye , Dong Chenlong , Dong Wujie , Wang Xin , Yuan Xiaotao , Huang Fuqiang
Published: April 2016

Earth-abundant and highly efficient electrocatalysts for the hydrogen evolution reaction (HER) are desired for hydrogen production from water-splitting.
Solvent-free synthesis of novel vanillidene derivatives of Meldrum's acid: biological evaluation, DNA and BSA binding study
Authors: Janković Nenad , Muškinja Jovana , Ratković Zoran , Bugarčić Zorica , Ranković Branislav , Kosanić Marijana , Stefanović Srđan
Published: April 2016

A series of novelO-alkyl vanillidene derivatives containing Meldrum's acid scaffold under solvent-free conditions were synthesized.
Metal chalcogenide quantum dots: biotechnological synthesis and applications
Authors: Mal J. , Nancharaiah Y. V. , van Hullebusch E. D. , Lens P. N. L.
Published: April 2016

Metal chalcogenide (metal sulfide, selenide and telluride) quantum dots (QDs) have attracted considerable attention due to their quantum confinement and size-dependent photoemission characteristics.
Perturbation theory model of reactivity and enantioselectivity of palladium-catalyzed Heck–Heck cascade reactions
Authors: Blázquez-Barbadillo C. , Aranzamendi E. , Coya E. , Lete E. , Sotomayor N. , González-Díaz H.
Published: April 2016

A new multi-output PT-QSRR model to correlate and predict the enantioselectivity and yield of Heck–Heck cascade reactions has been developed.
Will it gel? Successful computational prediction of peptide gelators using physicochemical properties and molecular fingerprints
Authors: Gupta Jyoti K. , Adams Dave J. , Berry Neil G.
Published: April 2016

We have successfully developed computational models, based on experimental data, which are robust and are able to identify in silico dipeptide structures that can form gels.
Casting molecular channels through domain formation: high performance graphene oxide membranes for H2/CO2separation
Authors: Achari A. , Eswaramoorthy M.
Published: April 2016

Annealed graphene oxide membranes show a severalfold increase in gas permeability without compromising the selectivity. This enhancement can be attributed to the formation of channels due to the creation of oxygen-rich and oxygen-deficient domains on the graphene oxide surface.
Maghemite-human serum albumin hybrid nanoparticles: towards a theranostic system with high MRI r2* relaxivity
Authors: Ishay Rivka Ben , Israel Liron L. , Eitan Esthy Levy , Partouche David M. , Lellouche Jean-Paul
Published: April 2016

Magnetic hybrid human serum albumin-based NPs were successfully fabricated, disclosing a powerful T2* contrast agent for dual therapeutic and diagnostic applications.
Facile in situ synthesis of dendrite-like ZnO/ZnTe core/shell nanorod heterostructures for sensitized solar cells
Authors: Luo Songping , Shen Heping , He Xiaoli , Zhang Ye , Li Jianbao , Oron Dan , Lin Hong
Published: April 2016

Band alignment modification upon the formation of ZnO/ZnTe heterostructure and the corresponding charge transfer process upon illumination.
Inferring catalysis in biological systems
Authors: Kondofersky Ivan , Theis Fabian J. , Fuchs Christiane
Published: April 2016

In systems biology, one is often interested in the communication patterns between several species, such as genes, enzymes or proteins. These patterns become more recognisable when temporal experiments are performed. This temporal communication can be structured by reaction networks such as gene regulatory networks or signalling pathways. Mathematical modelling of data arising from such networks can reveal important details, thus helping to understand the studied system. In many cases, however, corresponding models still deviate from the observed data. This may be due to unknown but present catalytic reactions. From a modelling perspective, the question of whether a certain reaction is catalysed leads to a large increase of model candidates. For large networks the calibration of all possible models becomes computationally infeasible. We propose a method which determines a substantially reduced set of appropriate model candidates and identifies the catalyst of each reaction at the same time. This is incorporated in a multiple‐step procedure which first extends the network by additional latent variables and subsequently identifies catalyst candidates using similarity analysis methods. Results from synthetic data examples suggest a good performance even for non‐informative data with few observations. Applied on CD95 apoptotic pathway our method provides new insights into apoptosis regulation.
Postoperative Cerebrospinal Fluid Leak Rates with Subfascial Epidural Drain Placement after Intentional Durotomy in Spine Surgery
Authors: Niu Tianyi , Lu Derek S. , Yew Andrew , Lau Darryl , Hoffman Haydn , McArthur David , Chou Dean , Lu Daniel C.
Published: April 2016

Study Design

Retrospective chart review.

Objective

Postoperative cerebrospinal fluid (CSF) leak is a known complication of intraoperative durotomy. Intraoperative placement of subfascial epidural drains following primary dural repair has been proposed as a potential management strategy to prevent formation of CSF cutaneous fistula and symptomatic pseudomeningocele. Here we describe our experience with subfascial drain after intentional durotomy.

Methods

Medical records of patients who underwent placement of subfascial epidural drains during spinal procedures with intentional intraoperative durotomies over a 4-year period at two institutions were retrospectively reviewed. Primary outcomes of interest were postoperative CSF cutaneous fistula or symptomatic pseudomeningocele formation.

Results

Twenty-five patients were included. Mean length of follow-up was 9.5 months. Twelve patients (48%) underwent simultaneous arthrodesis. The average duration of the drain was 5.3 days with average daily output of 126.5 mL. Subgroup analyses revealed that average drain duration for the arthrodesis group was 6.33 days, which is significantly greater than that of the nonfused group, which was 3.7 days ( p = 0.016). Similarly, the average daily drain output for the arthrodesis subgroup at 153.1 mL was significantly higher than that of the nonfused subgroup (86.8 mL, p = 0.04). No patient developed postoperative CSF cutaneous fistula or symptomatic pseudomeningocele or had negative sequelae associated with overdrainage of CSF. One patient had a delayed wound infection.

Conclusions

The intraoperative placement of subfascial epidural drains was not associated with postoperative development of CSF cutaneous fistula, symptomatic pseudomeningocele, overdrainage, or subdural hematoma in the cases reviewed. Subfascial closed wound drain placement is a safe and efficacious management method after intentional spinal durotomies. It is particularly helpful in those who undergo simultaneous arthrodesis, as those patients have statistically higher daily drain output and longer drain durations.
Measurement of dynamic surface tension by mechanically vibrated sessile droplets
Authors: Iwata Shuichi , Yamauchi Satoko , Yoshitake Yumiko , Nagumo Ryo , Mori Hideki , Kajiya Tadashi
Published: April 2016

We developed a novel method for measuring the dynamic surface tension of liquids using mechanically vibrated sessile droplets. Under continuous mechanical vibration, the shape of the deformed droplet was fitted by numerical analysis, taking into account the force balance at the drop surface and the momentum equation. The surface tension was determined by optimizing four parameters: the surface tension, the droplet’s height, the radius of the droplet-substrate contact area, and the horizontal symmetrical position of the droplet. The accuracy and repeatability of the proposed method were confirmed using drops of distilled water as well as viscous aqueous glycerol solutions. The vibration frequency had no influence on surface tension in the case of pure liquids. However, for water-soluble surfactant solutions, the dynamic surface tension gradually increased with vibration frequency, which was particularly notable for low surfactant concentrations slightly below the critical micelle concentration. This frequency dependence resulted from the competition of two mechanisms at the drop surface: local surface deformation and surfactant transport towards the newly generated surface.
Re-configurable multi-level temperature sensing by ultrasonic “spring-like” helical waveguide
Authors: Periyannan Suresh , Rajagopal Prabhu , Balasubramaniam Krishnan
Published: April 2016

This paper introduces a novel technique for multi-level temperature measurement using a single reconfigurable ultrasonic wire waveguide that is configured in the form of a helical spring. In this embodiment, the multiple sensing levels located along the length of the helical waveguide wire can be repositioned by stretching or collapsing the spring to provide measurements at different desired spacing in a given area/volume. This method can measure over a wide range of temperatures. The transduction is performed using Piezo-electric crystals that are attached to one end of the waveguide which act as transmitter as well as receiver. The wire will have multiple reflector embodiments (notches was used here) that allow reflections of input L(0,1) mode guided ultrasonic wave, in pulse echo mode, back to the crystal. Using the time of fight measurement at multiple predefined reflector locations, the local average temperatures are measured and compared with co-located thermocouples. The finite element modeling simulation was used to study the effect of excitation frequency and the mean coil diameter of the “spring-like” waveguide. This technique improves on the limitations of a straight waveguide technique earlier reported.
Oxidation of nickel surfaces through the energetic impacts of oxygen molecules: Reactive molecular dynamics simulations
Authors: Amiri Negar , Behnejad Hassan
Published: April 2016

Molecular dynamics approach accompanied by reactive force field is used to study the characteristics of the oxide growth process on Ni(100) and Ni(111) surfaces at the temperatures of 300, 600, and 900 K and 5 eV as the energy of the O2 impacts. The exposure of Ni surfaces to the high-energy O2 impacts indicates that the primary oxide nuclei can be formed on any impact site. The results of kinetic studies clarify that the oxide growth kinetics cannot be accurately explained with the island growth model and increasing the surface temperature raises failure of the model. Under the present conditions, the growth kinetics is found to obey a Langmuir growth model. Increasing the surface temperature from 300 to 900 K results in ∼18.75% and ∼23% more oxygen consumption by (100) and (111) surfaces of Ni, respectively. The structure of nickel oxide (NiO) film formed after 200 successive O2 impacts per surface super-cell is investigated utilizing radial distribution functions and oxygen density profiles. These calculations demonstrate that the structure of the formed NiO film is amorphous. Moreover, the charge profiles in Ni/NiO system are illustrated and discussed.
Multi-objective optimization of a natural aspirated three-cylinder spark ignition engine using modified non-dominated sorting genetic algorithm and multicriteria decision making
Authors: Shojaeefard Mohammad Hassan , Khalkhali Abolfazl , Firouzgan Alireza
Published: April 2016

The main purpose of this study is to find a special set of filling and emptying parameters of a three-cylinder engine, including geometrical design of intake manifold, intake and exhaust valve timing as design variables of the multi-objective optimization problem, which lead to the best values of BSFC (Brake Specific Fuel Consumption), and torque of the engine at all working speeds as four separate objective functions. The modified Non-dominated Sorting Genetic Algorithm (NSGA-II), which is an evolutionary Pareto-based method, is used as the optimization algorithm, and the technique for order of preference by similarity to ideal solution is used as a Multi-Criteria Decision Making Method to select the trade-off design based on different design strategies through the design vectors which are proposed. Group Method of Data Handling-type of Artificial Neural Networks is used to predict the relation between the design variables and the objective functions based on a 243-sized set of samples, which are chosen by Factorial method, and the corresponding engine designs are simulated using GT-SUITE as an Engine Simulation Software. The method of simulation is verified by comparison of experiment and simulation results. The verification process shows that the engine simulation code could predict the engine's performance by 4.78% error. Convergence and start point independence of the optimization algorithm (modified NSGA-II) is also investigated. The final results show remarkable improvement in BSFC and torque at 3500 RPM and mean value of BSFC at all working speeds along with a small reduction in mean value of the engine's torque at all working speeds compared to corresponding characteristics of a similar three-cylinder engine.
Ab initio molecular dynamics simulation study of successive hydrogenation reactions of carbon monoxide producing methanol
Authors: Pham Thi Nu , Ono Shota , Ohno Kaoru
Published: April 2016

Doing ab initio molecular dynamics simulations, we demonstrate a possibility of hydrogenation of carbon monoxide producing methanol step by step. At first, the hydrogen atom reacts with the carbon monoxide molecule at the excited state forming the formyl radical. Formaldehyde was formed after adding one more hydrogen atom to the system. Finally, absorption of two hydrogen atoms to formaldehyde produces methanol molecule. This study is performed by using the all-electron mixed basis approach based on the time dependent density functional theory within the adiabatic local density approximation for an electronic ground-state configuration and the one-shot GW approximation for an electronic excited state configuration.
A comparative study of sheath potential profile measurements with laser-heated and current-heated emissive probes
Authors: Kella Vara Prasad , Mehta Payal , Sarma A. , Ghosh J. , Chattopadhyay P. K.
Published: April 2016

Emissive Langmuir probe is one of the most efficient diagnostic tools available for plasma potential measurements. Extensive studies have been carried out in designing different kinds of conventional (electrically heated) emissive probes (CEPs) to estimate the plasma potential. Laser heated emissive probe (LHEP) has been developed with certain advantages over the conventional probes such as low evaporation rate of the probe material, high lifetime, and high emission levels. Most importantly, the LHEP uses laser to heat the probe-tip and does not require electric current to heat the probe-tip like in CEP. The heating current in CEP substantially affects the plasma potential measurements, especially in the regions of plasma where high electric and magnetic field gradients are present. In this paper, we studied the plasma potential structures in sheath-presheath region using both LHEP and CEP in an unmagnetized dc-filament discharge plasma. Measurements of sheath spatial potential profile using laser heated emissive probe are compared with those obtained using conventional emissive probe.
Morse potential-based model for contacting composite rough surfaces: Application to self-assembled monolayer junctions
Authors: Sierra-Suarez Jonatan A. , Majumdar Shubhaditya , McGaughey Alan J. H. , Malen Jonathan A. , Higgs C. Fred
Published: April 2016

This work formulates a rough surface contact model that accounts for adhesion through a Morse potential and plasticity through the Kogut-Etsion finite element-based approximation. Compared to the commonly used Lennard-Jones (LJ) potential, the Morse potential provides a more accurate and generalized description for modeling covalent materials and surface interactions. An extension of this contact model to describe composite layered surfaces is presented and implemented to study a self-assembled monolayer (SAM) grown on a gold substrate placed in contact with a second gold substrate. Based on a comparison with prior experimental measurements of the thermal conductance of this SAM junction [Majumdar et al., Nano Lett. 15, 2985–2991 (2015)], the more general Morse potential-based contact model provides a better prediction of the percentage contact area than an equivalent LJ potential-based model.
First-principle-based full-dispersion Monte Carlo simulation of the anisotropic phonon transport in the wurtzite GaN thin film
Authors: Wu Ruikang , Hu Run , Luo Xiaobing
Published: April 2016

In this study, we developed a first-principle-based full-dispersion Monte Carlo simulation method to study the anisotropic phonon transport in wurtzite GaN thin film. The input data of thermal properties in MC simulations were calculated based on the first-principle method. The anisotropy of thermal conductivity in bulk wurtzite GaN is found to be strengthened by isotopic scatterings and reduced temperature, and the anisotropy reaches 40.08% for natural bulk GaN at 100 K. With the GaN thin film thickness decreasing, the anisotropy of the out-of-plane thermal conductivity is heavily reduced due to both the ballistic transport and the less importance of the low-frequency phonons with anisotropic group velocities. On the contrary, it is observed that the in-plane thermal conductivity anisotropy of the GaN thin film is strengthened by reducing the film thickness. And the anisotropy reaches 35.63% when the natural GaN thin film thickness reduces to 50 nm at 300 K with the degree of specularity being zero. The anisotropy is also improved by increasing the surface roughness of the GaN thin film.
Fragmentation and constitutive response of tailored mesostructured aluminum compacts
Authors: Marquez Andrew M. , Braithwaite Christopher H. , Weihs Timothy P. , Krywopusk Nicholas M. , Gibbins David J. , Vecchio Kenneth S. , Meyers Marc A.
Published: April 2016

The fragmentation and constitutive response of aluminum-based compacts were examined under dynamic conditions using mesostructured powder compacts in which the interfaces between the powders (sizes of 40, 100, and 400 μm) were tailored during the swaging fabrication process. Fragmentation was induced in ring samples of this material through explosive loading and was examined through high speed photography, laser interferometry, and soft capture of fragments. Fragment velocities of around 100 m/s were recorded. The fragment mass distributions obtained correlated in general with the interfacial strength of the compacts as well as with the powder size. Experimental results are compared with fragmentation theories to characterize the behavior of reactive powders based on the material's mesostructure by introducing the fracture toughness of the compacts. The mean fragment size is calculated using a modified form of Mott's theory and successfully compared with experimental results.
Autonomous system for cross-organ investigation of ethanol-induced acute response in behaving larval zebrafish
Authors: Lin Xudong , Li Vincent W. T. , Chen Siya , Chan Chung-Yuen , Cheng Shuk-Han , Shi Peng
Published: April 2016

Ethanol is widely consumed and has been associated with various diseases in different organs. It is therefore important to study ethanol-induced responses in living organisms with the capability to address specific organs in an integrative manner. Here, we developed an autonomous system based on a series of microfluidic chips for cross-organ investigation of ethanol-induced acute response in behaving larval zebrafish. This system enabled high-throughput, gel-free, and anesthetic-free manipulation of larvae, and thus allowed real-time observation of behavioral responses, and associated physiological changes at cellular resolution within specific organs in response to acute ethanol stimuli, which would otherwise be impossible by using traditional methods for larva immobilization and orientation. Specifically, three types of chips (“motion,” “lateral,” and “dorsal”), based on a simple hydrodynamic design, were used to perform analysis in animal behavior, cardiac, and brain physiology, respectively. We found that ethanol affected larval zebrafish in a dose-dependent manner. The motor function of different body parts was significantly modulated by ethanol treatment, especially at a high dose of 3%. These behavioral changes were temporally associated with a slow-down of heart-beating and a stereotyped activation of certain brain regions. As we demonstrated in this proof-of-concept study, this versatile Fish-on-Chip platform could potentially be adopted for systematic cross-organ investigations involving chemical or genetic manipulations in zebrafish model.
Availability of surface boron species in improved oxygen reduction activity of Pt catalysts: A first-principles study
Authors: Zhang Libo , Zhou Gang
Published: April 2016

The oxidation process of boron (B) species on the Pt(111) surface and the beneficial effects of boron oxides on the oxygen reduction activity are investigated by first-principles calculations. The single-atom B anchored on the Pt surface has a great attraction for the oxygen species in the immediate environment. With the dissociation of molecular oxygen, a series of boron oxides is formed in succession, both indicating exothermic oxidation reactions. After BO2 is formed, the subsequent O atom immediately participates in the oxygen reduction reaction. The calculated O adsorption energy is appreciably decreased as compared to Pt catalysts, and more approximate to the optimal value of the volcano plot, from which is clear that O hydrogenation kinetics is improved. The modulation mechanism is mainly based on the electron-deficient nature of stable boron oxides, which normally reduces available electronic states of surface Pt atoms that bind the O by facilitating more electron transfer. This modification strategy from the exterior opens the new way, different from the alloying, to efficient electrocatalyst design for PEMFCs.
Network-scale effect on synchronizability of fully coupled network with connection delay
Authors: Zheng Y. G. , Wang Z. H.
Published: April 2016

Network-scale effect on synchronizability of fully coupled network with connection delay is investigated in this paper. The master stability function, which governs the stability of synchronization manifold, is first obtained by separating the synchronization manifold direction from other transverse directions. Then, by introducing a new time variable in the master stability function, it is shown the effect of connection delay can be weakened with the increase of network scale, and thus, in contrast to the situation without connection delay, large network scale is more positive to the synchronizability of fully coupled network with connection delay. Those findings are confirmed by the studies on two specific networks with nodes of typical nonlinear dynamical systems.
Peculiarities of high electric field conduction in p-type diamond
Authors: Mortet V. , Trémouilles D. , Bulíř J. , Hubík P. , Heller L. , Bedel-Pereira E. , Soltani A.
Published: April 2016

The electrical properties of chemical vapour deposited p-type epitaxial diamond layers are studied in high electric field conditions. The quasi-static current-voltage characteristics have been measured using transmission-line pulse method with 100 ns pulses. Reproducible impurity impact ionization avalanche breakdown occurs at a critical electrical field in the range of 100–200 kV cm−1 depending on the acceptor concentration and temperature, leading to complete ionisation of neutral impurities. The current-voltage characteristics exhibit an S-shape with the bi-stable conduction characteristic of impurity impact ionisation.
Growth kinetics and structural perfection of (InN)1/(GaN)1–20 short-period superlattices on +c-GaN template in dynamic atomic layer epitaxy
Authors: Kusakabe Kazuhide , Hashimoto Naoki , Itoi Takaomi , Wang Ke , Imai Daichi , Yoshikawa Akihiko
Published: April 2016

The growth kinetics and structural perfection of (InN)1/(GaN)1–20 short-period superlattices (SPSs) were investigated with their application to ordered alloys in mind. The SPSs were grown on +c-GaN template at 650 °C by dynamic atomic layer epitaxy in conventional plasma-assisted molecular beam epitaxy. It was found that coherent structured InN/GaN SPSs could be fabricated when the thickness of the GaN barrier was 4 ML or above. Below 3 ML, the formation of SPSs was quite difficult owing to the increased strain in the SPS structure caused by the use of GaN as a template. The effective or average In composition of the (InN)1/(GaN)4 SPSs was around 10%, and the corresponding InN coverage in the ∼1 ML-thick InN wells was 50%. It was found that the effective InN coverage in ∼1 ML-thick InN wells could be varied with the growth conditions. In fact, the effective In composition could be increased up to 13.5%, i.e., the corresponding effective InN coverage was about 68%, by improving the capping/freezing speed by increasing the growth rate of the GaN barrier layer.
Subthreshold-swing-adjustable tunneling-field-effect-transistor-based random-access memory for nonvolatile operation
Authors: Huh In , Cheon Woo Young , Choi Woo Young
Published: April 2016

A subthreshold-swing-adjustable tunneling-field-effect-transistor-based random-access memory (SAT RAM) has been proposed and fabricated for low-power nonvolatile memory applications. The proposed SAT RAM cell demonstrates adjustable subthreshold swing (SS) depending on stored information: small SS in the erase state (“1” state) and large SS in the program state (“0” state). Thus, SAT RAM cells can achieve low read voltage (Vread) with a large memory window in addition to the effective suppression of ambipolar behavior. These unique features of the SAT RAM are originated from the locally stored charge, which modulates the tunneling barrier width (Wtun) of the source-to-channel tunneling junction.
An optimized electroporation method for delivering nanoparticles into living cells for surface-enhanced Raman scattering imaging
Authors: Yu Yun , Wang Jing , Lin Juqiang , Lin Duo , Chen Weiwei , Feng Shangyuan , Huang Zufang , Li Yongzeng , Huang Hao , Shi Hong , Chen Rong
Published: April 2016

The existing electroporation method can rapidly deliver nanoparticles (NPs) into living cells for intracellular surface-enhanced Raman scattering (SERS) imaging. Unfortunately, the cellular SERS signals are major from molecules located near the two poles of the cell facing toward to the electrodes because most NPs enter cells through these two poles and easily happen to aggregate there. Here, we present an optimized electroporation method for transferring NPs into living cells to obtain a uniform NPs distribution. The distribution of intracellular NPs was monitored by the SERS signal of 4-mercaptobenzoic acid, which is sandwiched between the Au-Ag core-shell and validated by TEM images. In addition, based on this uniform distribution of NPs, we then detected the distribution of cellular molecules like phenylalanine and lipid via SERS imaging. Results demonstrate the great potential for the optimized electroporation-based SERS imaging in cellular study.
Scaling of electroresistance effect in fully integrated ferroelectric tunnel junctions
Authors: Abuwasib Mohammad , Lu Haidong , Li Tao , Buragohain Pratyush , Lee Hyungwoo , Eom Chang-Beom , Gruverman Alexei , Singisetti Uttam
Published: April 2016

Systematic investigation of the scalability for tunneling electroresistance (TER) of integrated Co/BaTiO3/SrRuO3 ferroelectric tunnel junctions (FTJs) has been performed from micron to deep submicron dimensions. Pulsed measurements of the transient currents confirm the ferroelectric switching behavior of the FTJs, while the hysteresis loops measured by means of piezoresponse force microscopy verify the scalability of these structures. Fully integrated functional FTJ devices with the size of 300 × 300 nm2 exhibiting a tunneling electroresistance (TER) effect of the order of 2.7 × 104% have been fabricated and tested. Measured current density of 75 A/cm2 for the ON state and a long polarization retention time of ON state (>10 h) show a lot of promise for implementation of high-density BaTiO3-based FTJ memory devices in future.
Pressure-induced structural transition of CdxZn1−xO alloys
Authors: Chen Yabin , Zhang Shuai , Gao Weiwei , Ke Feng , Yan Jinyuan , Saha Bivas , Ko Changhyun , Suh Joonki , Chen Bin , Ager Joel W. , Walukiewicz Wladek , Jeanloz Raymond , Wu Junqiao
Published: April 2016

CdxZn1−xO alloys, as a transparent conducting oxide, have recently attracted much attention for potential optoelectronic applications. In this letter, we report a hydrostatic pressure-induced phase transition of CdxZn1−xO alloys from the wurtzite to the rocksalt structure and its phase diagram probed using a diamond anvil cell. It is found that the transition pressure, determined by changes in optical and structural properties, depends sensitively on the composition. As the Cd content increases, the critical pressure decreases, until at x = 0.67 where the alloy is intrinsically stable in the rocksalt phase even at ambient pressure. The wurtzite phase is light emitting with a direct bandgap that slightly widens with increasing pressure, while the rocksalt phase has a much wider bandgap that is indirect. The pressure-sensitive light emission and phase transition may find potential applications in fields such as stress sensing and energy storage.
A defect detection method for MgB2 superconducting and iron-based Ba(Fe,Co)2As2 wires
Authors: Gajda D. , Morawski A. , Zaleski A. , Yamamoto A. , Cetner T.
Published: April 2016

In this article, a method allowing for the detection of damage in iron-based superconducting bulks and MgB2 wires is presented. MgB2 wires were made of in situ material with ex situ MgB2 barrier. The iron superconductor studied was Ba(Fe,Co)2As2. This material was surrounded by Nb barrier and placed inside an iron tube. All samples were annealed in the isostatic pressure of 1 GPa. Transport measurements were made using a four-contact probe. The transition of Nb and ex situ MgB2 barrier from superconducting into resistive state (first transition) was observed at a temperature range from 5 K to 10 K and can be attributed to damage in either the Nb or ex situ MgB2 barrier in these samples. For samples with a damaged barrier, it was not possible to determine the critical current density of the wires. The analysis indicates that annealing at 1 GPa leads to the Ba(Fe,Co)2As2 material with critical temperatures of 27 K and 21.5 K at upper critical flux density (Bc2) of 14 T.
Occupied and unoccupied electronic structures of an L-cysteine film studied by core-absorption and resonant photoelectron spectroscopies
Authors: Kamada M. , Hideshima T. , Azuma J. , Yamamoto I. , Imamura M. , Takahashi K.
Published: April 2016

Unoccupied and occupied electronic structures of an L-cysteine film have been studied by absorption and resonant photoelectron spectroscopies. Core absorptions at S-L, C-K, N-K, and O-K levels indicate that the lower unoccupied states are predominantly composed of oxygen-2p, carbon-2p, and sulfur-4s+3d orbitals, while higher unoccupied states may be attributed dominantly to nitrogen-np (n ≥ 3), oxygen-np (n ≥ 3), and sulfur-ns+md (n ≥ 4,  m ≥ 3) orbitals. Resonant photoelectron spectra at S-L23 and O-K levels indicate that the highest occupied state is originated from sulfur-3sp orbitals, while oxygen-2sp orbitals contribute to the deeper valence states. The delocalization lifetimes of the oxygen-1s and sulfur-2p excited states are estimated from a core-hole clock method to be about 9 ± 1 and 125 ± 25 fs, respectively.
Flammable Mexico
Authors: Pausas Juli G.
Published: April 2016

The frequency of disturbances is an important factor contributing to the megabiodiversity of Mexico, and fire is a prominent disturbance in this region. Here I briefly summarise important aspects of fire ecology in Mexico and introduce a new book for fire science in this country: Incendios de la vegetación (Vegetation fires) by D. Rodríguez-Trejo. The book covers many fire topics including fire ecology, fire behaviour, fire management, fire history and the anthropology of fire, and provides a basis for sustainable vegetation management in the region; it also advocates for the use of fire as a management tool. The message is that the biodiversity of Mexico, and therefore its management, cannot be understood without considering fire.
The pupylation machinery is involved in iron homeostasis by targeting the iron storage protein ferritin
Authors: Küberl Andreas , Polen Tino , Bott Michael
Published: April 2016

Significance

Pupylation is a posttranslational protein modification discovered in
Mycobacterium tuberculosis
in which it tags proteins for degradation via the proteasome. It thus resembles eukaryotic ubiquitination. In mycobacteria, pupylation plays a role under oxidative stress and under carbon and nitrogen starvation. Intriguingly, many bacteria containing the pupylation machinery lack a proteasome, such as corynebacteria, leaving the function of this protein modification open. We show that pupylation in
Corynebacterium glutamicum
plays a dedicated role in iron homeostasis by targeting the iron-storage protein ferritin. Evidence is provided that pupylation triggers the disassembly of 24-meric ferritin by ARC to support the release of the stored iron without using a protease. Thus, a physiological function of pupylation was discovered for a proteasome-free bacterial species.
The type III secretion system apparatus determines the intracellular niche of bacterial pathogens
Authors: Du Juan , Reeves Analise Z. , Klein Jessica A. , Twedt Donna J. , Knodler Leigh A. , Lesser Cammie F.
Published: April 2016

Significance

Bacterial pathogens use a variety of strategies to evade host cell innate immune responses. For some, this includes the establishment of an intracellular replicative niche. Although many intracellular pathogens remodel phagosomes to support bacterial replication, others lyse their internalization vacuole to reside within the host cell cytosol. Little is currently known regarding how bacteria, particularly Gram-negative pathogens, mediate phagosomal escape. Using complementary reductionist and functional interchangeability experimental approaches, we demonstrate that the type III secretion system machinery itself directly modulates the extent to which bacteria escape from phagosomes. Given the high prevalence of type III secretion systems among intracellular bacterial pathogens, these studies have identified a potential means by which the intracellular niche of Gram-negative bacteria is defined.
Mechanism of inhibition of human glucose transporter GLUT1 is conserved between cytochalasin B and phenylalanine amides
Authors: Kapoor Khyati , Finer-Moore Janet S. , Pedersen Bjørn P. , Caboni Laura , Waight Andrew , Hillig Roman C. , Bringmann Peter , Heisler Iring , Müller Thomas , Siebeneicher Holger , Stroud Robert M.
Published: April 2016

Significance

This paper reports the first structure of WT-human glucose transporter 1 (hGLUT1), to our knowledge, cocrystallized with inhibitors. The structures provide a template to develop therapeutic inhibitors applicable to cancers, because cancer cells become dependent on greatly increased glucose consumption. This dependence results in up-regulation of glucose transporter expression, especially hGLUT1. The bound inhibitors include the natural compound cytochalasin B and two of a series of previously undescribed organic compounds that bind in the submicromolar range. Our results emphasize that modulation of glucose import by hGLUTs should focus on making good interaction points for compounds and that the actual chemical backbone of the inhibitor is of less importance.
The Mass Spectra of the Lankacidin Antibiotics
Authors: Uramoto Masakazu , Ôtake Noboru
Published: April 2016

Bundlins A and B, antibiotics elaborated by Streptomyces sp. 6642 GC1, have the unique structures which possess a seventeen-membered carbon skeleton fused with an unusual β-keto-δ-Mactonic system and a pyruvamide side chain. In the course of the structural studies of the antibiotics, we found that these compounds showed the interesting fragmentations in their mass spectra and in consequence, the investigation about the interpretation of the principal peaks together with their formation mechanism was undertaken by the aid of high resolution mass spectrometry and the measurement of meta stable ions. In addition to the two antibiotics, the mass spectra of related compounds designated T–2636 D and T-2636 F were also investigated.
Interaction between Polyoxin and Active Center of Chitin Synthetase
Authors: Hori Masahiro , Kakiki Kazuo , Misato Tomomasa
Published: April 2016

Various derivatives of polyoxin C, other polyoxins and several uridine analogues have been known as competitive inhibitors of chitin-UDP acetylglucosaminyitransferase (EC 2.4.1.16, chitin synthetase). Their inhibitory activities were more or less dependent on pH. The variation of inhibitor constants Ki or Michaelis-Menten parameters Km and V with pH was investigated and the data obtained were plotted according to the method proposed by Dixon et al. From the results of the pKi-pH plots for the above competitive inhibitors, it was concluded that the ionized amino group at C−2″ position acted a very important role for the binding of polyoxins to chitin synthetase. The carbonyl oxygen atoms at C−1″ and of the carbamoyloxy group probably participated in the hydrogen bond formation with the enzyme. And pH scarcely influenced on the interaction between the carboxyl group at C−5″ and the enzyme. The results of the Dixon plots for variations of Km and V with pH suggested that an unionized imidazole group (pKa = 6.3) and an ionized amino group (pKa = 7.7) of chitin synthetase were concerned in the enzyme reaction.
Purification of a Nuclease from Penicillium citrinum
Authors: Fujimoto Masao , Kuninaka Akira , Yoshino Hiroshi
Published: April 2016

A nuclease was purified about 1500-fold with a recovery of 20% from an aqueous extract of culture of a pigmentless mutant VI–10–14 of Penicillium citrinum on wheat bran. The purified preparation was homogeneous on the basis of the criteria of ultracentrifugation and disc gel electrophoresis. The preparation was essentially free of 5′-nucleotidase, non-specific phosphomonoesterase, non-specific phosphodiesterase and 3′-monoester forming nuclease. The preparation hydrolyzed phosphodiester bonds in RNA and DNA to yield 5′-mononucleotides, and also the phosphomonoester bond in 2′- and 3′-AMP to yield nucleoside and inorganic phosphate. The enzyme activities toward these substrates were not separated and relative ratio of their specific activities remained constant throughout the purification, suggesting that a single enzyme was responsible for these activities.
Identity of Phosphodiesterase and Phosphomonoesterase Activities with Nuclease P1 (a Nuclease from Penicillium citrinum)
Authors: Fujimoto Masao , Kuninaka Akira , Yoshino Hiroshi
Published: April 2016

Enzymatic properties of a purified Penicillium nuclease (designated as nuclease P1) were investigated. The enzyme activities for RNA, heat-denatured DNA, native DNA, 3′-AMP and 2′-AMP showed a great degree of similarity with respect to the following properties: a) Range of stable pH (5~8), b) temperature optima (at around 70°C), c) thermostability (about 50% inactivation at 67°C, pH 6.0 for 15 min, d) effect of metal ions and SH inhibitors, e) requirement of Zn2+, f) protection from the heat-inactivation by albumin and Zn2+, g) inactivation on standing in the cold and reactivation on heating, h) sensitivity to protease, and i) competitive relationship between substrates in the enzyme reaction. Moreover, the ratio of enzyme activities in several mutants of Penicillium citrinum was constant. From these results, together with constant ratio of the specific activities throughout purification, it is concluded that a single enzyme might be responsible for both phosphodiesterase and phosphomonoesterase functions.
A New Growth Effecting Peptide of Bacillus Species from Soybean Cake
Authors: Chiyonobu Toshikazu , Shirai Katsuhisa , Adachi Osao , Ameyama Minoru
Published: April 2016

A new peptide, which has a marked effect on the growth of Bacillus species, was purified from soybean cake by a procedure employing ammonium sulfate fractionation, and active charcoal-, DEAE-Sephadex A–25- and Sephadex gel-column chromatographies. The purified peptide gave a single band on paper electrophoresis. The peptide possessed the following properties: specific extinction (E at 280nm), 11.9; N-terminal amino acid, glutamate; molecular weight, 8058; total number of amino acid, 70; chemical composition (%), C, 49.12; H, 6.26; N, 16.44; and S, 2.34; isoelectric point, pH4.3. The hydrolyzed peptide had no stimulative effect on the growth of Bacillus species. Especially, those microorganisms belonging to the genera of Bacillus, Arthrobacter and Xanthomonas were remarkably sensitive to the peptide.
Effect of the axial external magnetic field on copper/aluminium arc weld joining
Authors: Liu Y. B. , Sun Q. J. , Wang H. , Zhang H. M. , Cai S. J. , Feng J. C.
Published: April 2016

Pure copper and aluminium alloy was joined by cold metal transfer welding with the assistance of an axial external magnetic field in this work. The results reveal that magnetic field led to a reduction of the average heat input and improved the wetting behaviour of the weld metal on the copper sheet surface. The thickness of the Al2Cu intermetallic compound layer formed at the interface was decreased from 50 µm for normal welding to 5 µm for the magnetic field-assisted welding process. The joint strength was observed to increase with the magnetic field. For a 21 mT and 10 Hz magnetic field, the maximum loading force reached up to 1.67 kN, resulting in an increase in joint strength by 33%.
Freshwater ecosystems and aquatic insects: a paradox in biological invasions
Authors: Fenoglio Stefano , Bonada Núria , Guareschi Simone , López-Rodríguez Manuel J. , Millán Andrés , Tierno de Figueroa J. Manuel
Published: April 2016

Biological invasions have increased significantly in response to global change and constitute one of the major causes of biodiversity loss. Insects make up a large fraction of invasive species, in general, and freshwaters are among the most invaded ecosystems on our planet. However, even though aquatic insects dominate most inland waters, have unparalleled taxonomic diversity and occupy nearly all trophic niches, there are almost no invasive insects in freshwaters. We present some hypotheses regarding why aquatic insects are not common among aquatic invasive organisms, suggesting that it may be the result of a suite of biological, ecological and anthropogenic factors. Such specific knowledge introduces a paradox in the current scientific discussion on invasive species; therefore, a more in-depth understanding could be an invaluable aid to disentangling how and why biological invasions occur.
Imprinting can cause a maladaptive preference for infectious conspecifics
Authors: Stephenson Jessica F. , Reynolds Michael
Published: April 2016

Recognizing and associating with specific individuals, such as conspecifics or kin, brings many benefits. One mechanism underlying such recognition is imprinting: the long-term memory of cues encountered during development. Typically, juveniles imprint on cues of nearby individuals and may later associate with phenotypes matching their ‘recognition template’. However, phenotype matching could lead to maladaptive social decisions if, for instance, individuals imprint on the cues of conspecifics infected with directly transmitted diseases. To investigate the role of imprinting in the sensory ecology of disease transmission, we exposed juvenile guppies,Poecilia reticulata, to the cues of healthy conspecifics, or to those experiencing disease caused by the directly transmitted parasiteGyrodactylus turnbulli. In a dichotomous choice test, adult ‘disease-imprinted’ guppies preferred to associate with the chemical cues ofG. turnbulli-infected conspecifics, whereas ‘healthy-imprinted’ guppies preferred to associate with cues of uninfected conspecifics. These responses were only observed when stimulus fish were in late infection, suggesting imprinted fish responded to cues of disease, but not of infection alone. We discuss how maladaptive imprinting may promote disease transmission in natural populations of a social host.
Ultrasonic hearing and echolocation in the earliest toothed whales
Authors: Park Travis , Fitzgerald Erich M. G. , Evans Alistair R.
Published: April 2016

The evolution of biosonar (production of high-frequency sound and reception of its echo) was a key innovation of toothed whales and dolphins (Odontoceti) that facilitated phylogenetic diversification and rise to ecological predominance. Yet exactly when high-frequency hearing first evolved in odontocete history remains a fundamental question in cetacean biology. Here, we show that archaic odontocetes had a cochlea specialized for sensing high-frequency sound, as exemplified by an Oligocene xenorophid, one of the earliest diverging stem groups. This specialization is not as extreme as that seen in the crown clade. Paired with anatomical correlates for high-frequency signal production in Xenorophidae, this is strong evidence that the most archaic toothed whales possessed a functional biosonar system, and that this signature adaptation of odontocetes was acquired at or soon after their origin.
Reduced flight-to-light behaviour of moth populations exposed to long-term urban light pollution
Authors: Altermatt Florian , Ebert Dieter
Published: April 2016

The globally increasing light pollution is a well-recognized threat to ecosystems, with negative effects on human, animal and plant wellbeing. The most well-known and widely documented consequence of light pollution is the generally fatal attraction of nocturnal insects to artificial light sources. However, the evolutionary consequences are unknown. Here we report that moth populations from urban areas with high, globally relevant levels of light pollution over several decades show a significantly reduced flight-to-light behaviour compared with populations of the same species from pristine dark-sky habitats. Using a common garden setting, we reared moths from 10 different populations from early-instar larvae and experimentally compared their flight-to-light behaviour under standardized conditions. Moths from urban populations had a significant reduction in the flight-to-light behaviour compared with pristine populations. The reduced attraction to light sources of ‘city moths' may directly increase these individuals' survival and reproduction. We anticipate that it comes with a reduced mobility, which negatively affects foraging as well as colonization ability. As nocturnal insects are of eminent significance as pollinators and the primary food source of many vertebrates, an evolutionary change of the flight-to-light behaviour thereby potentially cascades across species interaction networks.