bluuebunny/crossref_metadata_2025 huggingface dataset:
‘Drugs, religion and chemistry in Tanzania’: an interactive seminar for chemistry students
Authors: Buchanan Malcolm S.
Published: April 2015

Most Tanzanian Higher Education Institutes do not have the materials and technology to give students a significant practical experience in the sciences. In 2013 Tanzania was rated 159th out of 187 countries for ‘human development’ (United Nations Development Program 2014 Report). In order to supplement their current, limited practical experience, a culturally relevant, interactive seminar which makes the chemical sciences real to the world of Tanzanians was developed. This was achievedviaa Natural Product Drug Discovery seminar during which Tanzanian students were able to appreciate how Tanzanian culture is connected with the fundamentals and applications of the chemical sciences (in this case natural product drug discovery to combat diseases prevalent in Tanzania). Post-seminar evaluation and, observation of student behaviour and chemistry staff feedback supported the value of this seminar. An interactive seminar such as this provides an innovative method of chemical education, useful to motivate final year students and provide them with new ideas before they go into their communities to teach chemistry.
Bottom-up on-crystal in-chip formation of a conducting salt and a view of its restructuring: from organic insulator to conducting “switch” through microfluidic manipulation
Authors: Puigmartí-Luis Josep , Paradinas Markos , Bailo Elena , Rodriguez-Trujillo Romen , Pfattner Raphael , Ocal Carmen , Amabilino David B.
Published: April 2015

The chemical modification of an immobilized single crystal in a fluid cell is reported, whereby a material with switching functions is generated with reagent in the stream.
A model of vesicle tubulation and pearling induced by adsorbing particles
Authors: Su Yu-Cheng , Chen Jeff Z. Y.
Published: April 2015

A transition path sequence is found, similar to the observation in a recent experiment, for the tubulation and pearling transition of a vesicle immersed in a nanoparticle solution.
Improved photovoltaic performance of star-shaped molecules with a triphenylamine core by tuning the substituted position of the carbazolyl unit at the terminal
Authors: Zhou Pei , Dang Dongfeng , Xiao Manjun , Wang Qiong , Zhong Juan , Tan Hua , Pei Yong , Yang Renqiang , Zhu Weiguo
Published: April 2015

Significantly enhanced photovoltaic performance with a PCE up to 3.94% was achieved by tuning the substituted positions of the carbazolyl unit at the terminal.
An organophosphine oxide redox shuttle additive that delivers long-term overcharge protection for 4 V lithium-ion batteries
Authors: Huang Jinhua , Azimi Nasim , Cheng Lei , Shkrob Ilya A. , Xue Zheng , Zhang Junjie , Dietz Rago Nancy L. , Curtiss Larry A. , Amine Khalil , Zhang Zhengcheng , Zhang Lu
Published: April 2015

Redox shuttle additives are used to protect Li-ion batteries from overcharge.
Novel 1,8-naphthalimide derivatives for standard-red organic light-emitting device applications
Authors: Luo Shuai , Lin Jie , Zhou Jie , Wang Yi , Liu Xingyuan , Huang Yan , Lu Zhiyun , Hu Changwei
Published: April 2015

A 1,8-naphthalimide derivative has been demonstrated to be a high performance standard-red EL material.
An indigo-based polymer bearing thermocleavable side chains for n-type organic thin film transistors
Authors: Guo Chang , Quinn Jesse , Sun Bin , Li Yuning
Published: April 2015

A new n-type semiconducting polymer based on indigo with thermocleavable tert-butoxycarbonyl (t-Boc) groups was synthesized and used as an active layer in organic thin film transistors.
Solution processed blue phosphorescent organic light emitting diodes using a Ge-based small molecular host
Authors: Yao Chuang , Cui Qianling , Peng Jinghong , Xu Xinjun , Liu Ronghua , Wang Jinshan , Tian Yuan , Li Lidong
Published: April 2015

A novel Ge-based host material is screened using theoretical calculations and synthesized for use as solution processed blue PhOLEDs.
Low temperature synthesis of graphite on Ni films using inductively coupled plasma enhanced CVD
Authors: Cheng Lanxia , Yun Kayoung , Lucero Antonio , Huang Jie , Meng Xin , Lian Guoda , Nam Ho-Seok , Wallace Robert M. , Kim Moon , Venugopal Archana , Colombo Luigi , Kim Jiyoung
Published: April 2015

Synthesis of good quality graphite on Ni using IC-PECVD at a low temperature of 380 °C in a hydrogen free environment.
Lopimune-induced mitochondrial toxicity is attenuated by increased uncoupling protein-2 level in treated mouse hepatocytes
Authors: Hoss Sara El , Bahr Georges M. , Echtay Karim S.
Published: April 2015

Although the protease inhibitor (PI) Lopimune has proven to be effective, no studies have examined the side effects of Lopimune on mitochondrial bioenergetics in hepatocytes. The objective of the present study is to evaluate mitochondrial respiration, production of reactive oxygen species (ROS) and expression of uncoupling protein-2 (UCP2) in mouse hepatocytes following Lopimune administration. Mitochondria were extracted from mouse liver using differential centrifugation and hepatocytes were isolated by the collagenase perfusion procedure. Mitochondrial respiration was measured using a Rank Brothers oxygen electrode. ROS production in hepatocytes was monitored by flow cytometry using a 2′,7′-dichlorofluorescin diacetate probe and UCP2 protein expression was detected by Western blotting. We found that Lopimune induced a significant decrease of approximately 30% in the respiratory control ratio (RCR) starting from day 4 until day 9 of treatment. This decrease was due to an increase in state 4 respiration, reflecting an increase in mitochondrial proton leak. State 2 and state 3 respirations were not affected. Moreover, ROS production significantly increased by about 2-fold after day 1 of treatment and decreased after day 3, returning to the resting level on day 5. Interestingly, UCP2 which is absent from control hepatocytes, was expressed starting from day 4 of treatment. Our findings indicate that Lopimune-induced proton leak, mediated by UCP2, may represent a response to inhibit the production of ROS as a negative feedback regulatory mechanism. These results imply a potential involvement of UCP2 in the regulation of oxidative stress and add new insights into the understanding of mitochondrial toxicity induced by PIs.
Stability and stabilisation of reset control systems with uncertain output matrix
Authors: Zhao Guanglei , Wang Jingcheng
Published: April 2015

The stability analysis of reset control systems is challenging when reset time instants are uncertain, because such uncertainties may damage or even destabilise the system. This study considers reset control systems with uncertain output matrix, and presents sufficient conditions for the quadratic stability and finite gain ℒ2 stability of the closed‐loop reset systems. Then, the results are extended to piecewise quadratic stability, which is much less conservative. The design of the reset controller is also discussed. All the results are given as linear matrix inequalities by using a lemma about multi‐convex function. Several examples are given to show the effectiveness of the obtained results.
Stability and performance analysis of unmanned aerial vehicles: Quadrotor against Hexrotor
Authors: Toledo Jonay , Acosta Leopoldo , Perea Daniel , Morales Nestor
Published: April 2015

Multirotor helicopters are very powerful flying robots used in many applications, but their lack is robustness. A fail in any of their rotors can drive the helicopter to fall. In this study two different micro‐helicopter structures are analysed, a standard Quadrotor and a Hexrotor. An uncertainty model is generated and a robust controller is designed. The structured singular value μΔ is used to test the robust stability and performance of these two plants, obtaining better results for Hex than Quadrotor. At the end of the study, a set of flight tests, where some of the motors are partially damaged, is presented confirming the analysis of μΔ. Results of this study show Hexrotor as a very interesting structure for unmanned aerial vehiclesbecause of its stability and performance characteristics compared with Quadrotor.
Input‐series and output‐parallel connected single stage buck type modular AC–DC converters with high‐frequency isolation
Authors: Xu Guo , Sha Deshang , Liao Xiaozhong
Published: April 2015

An input‐series‐output‐parallel connected single stage buck type modular AC–DC converter with high‐frequency isolation is presented in this study. The configuration possesses the following characteristics: (i) single‐stage conversion, (ii) high‐frequency isolation, (iii) using low voltage rating power devices. A stable control strategy based on the analysis of the three working states is proposed to achieve input voltage sharing automatically through output current sharing without sampling input voltages. With the strategy, equal power sharing can be obtained in both steady and dynamic state, even in the case when the parameters of individual modules are mismatched. The control loop modelling and design are given to show the stability of the control scheme and design of the controllers. The effectiveness of the presented topology and proposed control strategy are verified by simulations and experimental results.
Fast circuit model for interaction of open‐ended rectangular waveguide probes with arbitrary‐shape surface cracks in metals
Authors: Ahanian Iman , Sadeghi Seyed Hossein Hesamedin , Moini Rouzbeh
Published: April 2015

The study proposes a fast modelling technique to predict output signal of an open‐ended rectangular waveguide when scanning an arbitrary‐shape surface crack in a metal. In this technique, the crack is first segmented into an appropriate number of short rectangular waveguides each of which is modelled by a two‐port network with an equivalent RLC circuit. The generalised scattering matrix technique is then used to predict the probe output signal. The efficiency of the proposed model is demonstrated by comparing the simulation results of several case studies with measurements and those obtained using the mode‐matching method and a commercial finite integration technique code.
Gestion de la dimension transversale maxillaire
Authors: Caquant Ludovic
Published: April 2015

La correction des anomalies transversales est un domaine particulier en orthodontie et en
chirurgie maxillo-faciale. La stabilité du résultat est souvent problématique malgré la
diversité des moyens thérapeutiques. Nous expliquons le procédé physiopathologique de ce
défaut de croissance transversale et proposons un arbre décisionnel.
La chirurgie de première intention : indications, avantages et
inconvénients
Authors: Le Gall Michel , Mattera Rémi , Cheynet François
Published: April 2015

La chirurgie de première intention constitue une option supplémentaire pour nos
traitements. Contrairement au protocole orthodontico-chirurgical classique en trois
étapes, elle vise à corriger le décalage squelettique dans un premier temps, pour
restituer un environnement fonctionnel favorable et permettre, dans un second temps, de
corriger orthodontiquement l’occlusion du patient. Elle consiste, dans certains cas de
dysmorphies maxillo-mandibulaires et pour des indications qui lui sont spécifiques, à
supprimer ou réduire à minima la préparation orthodontique pré-chirurgicale. D’un point de
vue orthodontique, elle permet de réduire la durée globale du traitement, facilite le
traitement ultérieur à la chirurgie et accélère le déplacement dentaire. Du point de vue
du patient, elle permet une amélioration esthétique rapide et une qualité de vie
radicalement améliorée. L’utilisation de moyens d’ancrages, de gouttières chirurgicales ou
de set-up permet de pallier les inconvénients de cette technique que
peuvent être une occlusion post-chirurgicale instable, ou une planification étroite du
plan de traitement.
A kMC-MD method with generalized move-sets for the simulation of folding of α-helical and β-stranded peptides
Authors: Peter Emanuel K. , Pivkin Igor V. , Shea Joan-Emma
Published: April 2015

In Monte-Carlo simulations of protein folding, pathways and folding times depend on the appropriate choice of the Monte-Carlo move or process path. We developed a generalized set of process paths for a hybrid kinetic Monte Carlo—Molecular dynamics algorithm, which makes use of a novel constant time-update and allows formation of α-helical and β-stranded secondary structures. We apply our new algorithm to the folding of 3 different proteins: TrpCage, GB1, and TrpZip4. All three systems are seen to fold within the range of the experimental folding times. For the β-hairpins, we observe that loop formation is the rate-determining process followed by collapse and formation of the native core. Cluster analysis of both peptides reveals that GB1 folds with equal likelihood along a zipper or a hydrophobic collapse mechanism, while TrpZip4 follows primarily a zipper pathway. The difference observed in the folding behavior of the two proteins can be attributed to the different arrangements of their hydrophobic core, strongly packed, and dry in case of TrpZip4, and partially hydrated in the case of GB1.
Linear and third- and fifth-order nonlinear spectroscopies of a charge transfer system coupled to an underdamped vibration
Authors: Dijkstra Arend G. , Tanimura Yoshitaka
Published: April 2015

We study hole, electron, and exciton transports in a charge transfer system in the presence of underdamped vibrational motion. We analyze the signature of these processes in the linear and third-, and fifth-order nonlinear electronic spectra. Calculations are performed with a numerically exact hierarchical equations of motion method for an underdamped Brownian oscillator spectral density. We find that combining electron, hole, and exciton transfers can lead to non-trivial spectra with more structure than with excitonic coupling alone. Traces taken during the waiting time of a two-dimensional (2D) spectrum are dominated by vibrational motion and do not reflect the electron, hole, and exciton dynamics directly. We find that the fifth-order nonlinear response is particularly sensitive to the charge transfer process. While third-order 2D spectroscopy detects the correlation between two coherences, fifth-order 2D spectroscopy (2D population spectroscopy) is here designed to detect correlations between the excited states during two different time periods.
Optically induced transport through semiconductor-based molecular electronics
Authors: Li Guangqi , Fainberg Boris D. , Seideman Tamar
Published: April 2015

A tight binding model is used to investigate photoinduced tunneling current through a molecular bridge coupled to two semiconductor electrodes. A quantum master equation is developed within a non-Markovian theory based on second-order perturbation theory with respect to the molecule-semiconductor electrode coupling. The spectral functions are generated using a one dimensional alternating bond model, and the coupling between the molecule and the electrodes is expressed through a corresponding correlation function. Since the molecular bridge orbitals are inside the bandgap between the conduction and valence bands, charge carrier tunneling is inhibited in the dark. Subject to the dipole interaction with the laser field, virtual molecular states are generated via the absorption and emission of photons, and new tunneling channels open. Interesting phenomena arising from memory are noted. Such a phenomenon could serve as a switch.
Ab initio
molecular dynamics simulation of liquid water by quantum Monte Carlo
Authors: Zen Andrea , Luo Ye , Mazzola Guglielmo , Guidoni Leonardo , Sorella Sandro
Published: April 2015

Although liquid water is ubiquitous in chemical reactions at roots of life and climate on the earth, the prediction of its properties by high-level ab initio molecular dynamics simulations still represents a formidable task for quantum chemistry. In this article, we present a room temperature simulation of liquid water based on the potential energy surface obtained by a many-body wave function through quantum Monte Carlo (QMC) methods. The simulated properties are in good agreement with recent neutron scattering and X-ray experiments, particularly concerning the position of the oxygen-oxygen peak in the radial distribution function, at variance of previous density functional theory attempts. Given the excellent performances of QMC on large scale supercomputers, this work opens new perspectives for predictive and reliable ab initio simulations of complex chemical systems.
On the cohomology of Leibniz conformal algebras
Authors: Zhang Jiao
Published: April 2015

We construct a new cohomology complex of Leibniz conformal algebras with coefficients in a representation instead of a module. The low-dimensional cohomology groups of this complex are computed. Meanwhile, we construct a Leibniz algebra from a Leibniz conformal algebra and prove that the category of Leibniz conformal algebras is equivalent to the category of equivalence classes of formal distribution Leibniz algebras.
Gold-doped graphene: A highly stable and active electrocatalysts for the oxygen reduction reaction
Authors: Stolbov Sergey , Alcántara Ortigoza Marisol
Published: April 2015

In addressing the growing need of renewable and sustainable energy resources, hydrogen-fuel-cells stand as one of the most promising routes to transform the current energy paradigm into one that integrally fulfills environmental sustainability. Nevertheless, accomplishing this technology at a large scale demands to surpass the efficiency and enhance the cost-effectiveness of platinum-based cathodes, which catalyze the oxygen reduction reaction (ORR). In this work, our first-principles calculations show that Au atoms incorporated into graphene di-vacancies form a highly stable and cost-effective electrocatalyst that is, at the same time, as or more (dependently of the dopant concentration) active toward ORR than the best-known Pt-based electrocatalysts. We reveal that partial passivation of defected-graphene by gold atoms reduces the reactivity of C dangling bonds and increases that of Au, thus optimizing them for catalyzing the ORR and yielding a system of high thermodynamic and electrochemical stabilities. We also demonstrate that the linear relation among the binding energies of the reaction intermediates assumed in computational high-throughput material screening does not hold, at least for this non-purely transition-metal material. We expect Au-doped graphene to finally overcome the cathode-related challenge hindering the realization of hydrogen-fuel cells as the leading means of powering transportation and portable devices.
Control of coherence among the spins of a single electron and the three nearest neighbor 13C nuclei of a nitrogen-vacancy center in diamond
Authors: Shimo-Oka T. , Kato H. , Yamasaki S. , Jelezko F. , Miwa S. , Suzuki Y. , Mizuochi N.
Published: April 2015

Individual nuclear spins in diamond can be optically detected through hyperfine couplings with the electron spin of a single nitrogen-vacancy (NV) center; such nuclear spins have outstandingly long coherence times. Among the hyperfine couplings in the NV center, the nearest neighbor 13C nuclear spins have the largest coupling strength. Nearest neighbor 13C nuclear spins have the potential to perform fastest gate operations, providing highest fidelity in quantum computing. Herein, we report on the control of coherences in the NV center where all three nearest neighbor carbons are of the 13C isotope. Coherence among the three and four qubits are generated and analyzed at room temperature.
Bacteria repelling on highly-ordered alumina-nanopore structures
Authors: Kim Sunghan , Zhou Yan , Cirillo Jeffrey D. , Polycarpou Andreas A. , Liang Hong
Published: April 2015

Bacteria introduce diseases and infections to humans by their adherence to biomaterials, such as implants and surgical tools. Cell desorption is an effective step to reduce such damage. Here, we report mechanisms of bacteria desorption. An alumina nanopore structure (ANS) with pore size of 35 nm, 55 nm, 70 nm, and 80 nm was used as substrate to grow Escherichia coli (E. coli) cells. A bacteria repelling experimental method was developed to quantitatively evaluate the area percentage of adherent bacterial cells that represent the nature of cell adhesion as well as desorption. Results showed that there were two crucial parameters: contact angle and contact area that affect the adhesion/desorption. The cells were found to be more easily repelled when the contact angle increased. The area percentage of adherent bacterial cells decreased with the decrease in the contact area of a cell on ANS. This means that cell accessibility on ANS depends on the contact area. This research reveals the effectiveness of the nanopored structures in repelling cells.
On turbulent mixing in stably stratified wall-bounded flows
Authors: Karimpour Farid , Venayagamoorthy Subhas Karan
Published: April 2015

In this paper, we provide an analysis of turbulent mixing in stably stratified wall-bounded flows to highlight a number of important issues such as prediction of the turbulent viscosity, the turbulent diffusivity, and the irreversible flux Richardson number. By invoking the equilibrium assumption between the production rate of the turbulent kinetic energy (P), the dissipation rate of the turbulent kinetic energy (ϵ), and the turbulent potential energy dissipation rate (ϵPE) as P ≈ ϵ + ϵPE and also assuming equilibrium between the buoyancy flux (B) and ϵPE as −B ≈ ϵPE, we first propose that the irreversible flux Richardson number (Rf∗=ϵPE/(ϵ+ϵPE)) can be approximated with the flux Richardson number (Rf = − B/P), especially for low gradient Richardson numbers. Second, we propose that the turbulent viscosity νt≈(1−Rf∗)−1ϵ/S2, where S is the mean shear rate. We then extend our analysis to propose appropriate velocity and length scales. Tests using the direct numerical simulation (DNS) data of turbulent channel flow of García-Villalba and del Álamo [“Turbulence modification by stable stratification in channel flow,” Phys. Fluids 23, 045104 (2011)] are performed to evaluate our propositions. The comparisons between the exact turbulent viscosity, length and velocity scales, and the proposed formulations are excellent. Also, the agreement between Rf and Rf∗ is reasonable for the bulk of the flow depth with differences of about 20% on average, except at depths very close to the flow boundaries. Finally, by invoking the equilibrium assumption between the buoyancy flux (B) and the dissipation rate of the turbulent potential energy (ϵPE) as −B ≈ ϵPE, we infer the turbulent diffusivity as κt ≈ ϵPE/N2, where N is the buoyancy frequency. The comparison of the proposed turbulent diffusivity with the exact turbulent diffusivity computed from DNS data is good especially close to the wall but the agreement deteriorates far away from the wall, indicating the breakdown of assuming equilibrium as −B ≈ ϵPE which is attributed to the presence of linear internal wave motions in this far-wall region.
Investigation of surface-plasmon coupled red light emitting InGaN/GaN multi-quantum well with Ag nanostructures coated on GaN surface
Authors: Li Yi , Liu Bin , Zhang Rong , Xie Zili , Zhuang Zhe , Dai JiangPing , Tao Tao , Zhi Ting , Zhang Guogang , Chen Peng , Ren Fangfang , Zhao Hong , Zheng Youdou
Published: April 2015

Surface-plasmon (SP) coupled red light emitting InGaN/GaN multiple quantum well (MQW) structure is fabricated and investigated. The centre wavelength of 5-period InGaN/GaN MQW structure is about 620 nm. The intensity of photoluminescence (PL) for InGaN QW with naked Ag nano-structures (NS) is only slightly increased due to the oxidation of Ag NS as compared to that for the InGaN QW. However, InGaN QW with Ag NS/SiO2 structure can evidently enhance the emission efficiency due to the elimination of surface oxide layer of Ag NS. With increasing the laser excitation power, the PL intensity is enhanced by 25%–53% as compared to that for the SiO2 coating InGaN QW. The steady-state electric field distribution obtained by the three-dimensional finite-difference time-domain method is different for both structures. The proportion of the field distributed in the Ag NS for the GaN/Ag NS/SiO2 structure is smaller as compared to that for the GaN/naked Ag NS structure. As a result, the energy loss of localized SP modes for the GaN/naked Ag NS structure will be larger due to the absorption of Ag layer.
Microstructural and magnetic properties of Nd-Fe-B alloys processed by equal-channel angular pressing
Authors: Onal E. , Lapovok R. , Kishimoto H. , Kato A. , Davies C. H. J. , Suzuki K.
Published: April 2015

Equal-channel angular pressing (ECAP) is a well-established thermo-mechanical processing technique. This technique allows virtually unlimited strain and manipulation of texture by processing route, while the cross-section of the sample remains unchanged during processing. In order to clarify the effectiveness of ECAP on preparing anisotropic permanent magnets, the microstructure and magnetic properties of a melt-spun Nd13.5Fe73.8Co6.7B5.6Ga0.4 alloy processed at 773 K for 300 s by ECAP were investigated. Macrotexture analysis carried out for the exit channel of ECAP shows that the basal plane of the tetragonal Nd2Fe14B crystal aligns parallel to the shear band, i.e., the c-axis texture formation normal to the shear band induced by the ECAP process. Due to this texture formation, the technical magnetization behaviour becomes anisotropic, and the remanent magnetization is clearly enhanced along the direction perpendicular to the shear band. This anisotropic microstructure is realized at a relatively low processing temperature of 773 K, well below the melting point of the Nd-rich intergranular phase. As a consequence of this lower processing temperature, the nanostructure of the melt-spun alloy remains approximately 20 to 30 nm, considerably smaller than the typical grain size obtained after conventional die-upsetting. Our study demonstrates that equal-channel angular pressing has a potential for realising anisotropic nanostructured magnets.
Thermal radiation from optically driven Kerr (χ(3)) photonic cavities
Authors: Khandekar Chinmay , Lin Zin , Rodriguez Alejandro W.
Published: April 2015

We describe thermal radiation from nonlinear (χ(3)) photonic cavities coupled to external channels and subject to incident monochromatic light. Our work extends related work on nonlinear mechanical oscillators to the problem of thermal radiation, demonstrating that bistability can enhance thermal radiation by orders of magnitude and result in strong lineshape alternations, including “super-narrow spectral peaks” occurring at the onset of kinetic phase transitions. We show that when the cavities are designed to exhibit perfect linear emissivity (rate matching), such thermally activated transitions can be exploited to dramatically tune the output power and radiative properties of the cavity, leading to a kind of Kerr-mediated thermo-optic effect. Finally, we demonstrate that in certain parameter regimes, the output radiation exhibits Stokes and anti-Stokes side peaks whose relative magnitudes can be altered by tuning the internal temperature of the cavity relative to its surroundings, a consequence of strong correlations and interference between the emitted and reflected radiation.
Multiple-receptor wireless power transfer for magnetic sensors charging on Mars via magnetic resonant coupling
Authors: Liu Chunhua , Chau K. T. , Zhang Zhen , Qiu Chun , Lin Fei , Ching T. W.
Published: April 2015

This paper proposes a new idea for magnetic sensors charging on Mars, which aims to effectively transmit energy from Mars Rover to distributed magnetic sensors. The key is to utilize wireless power transfer (WPT) to enable multiple receptors extracting energy from the source via magnetic resonant coupling. Namely, the energy transmitter is located on the Mars Rover, whereas the energy receptor is installed in the magnetic sensor. In order to effectively transfer the power, a resonator is installed between the transmitter and the receptors. Based on the proposed idea, the system topology, operation principle, and simulation results are developed. By performing finite element magnetic field analysis, the output power and efficiency of the proposed WPT system are evaluated. It confirms that the Mars Rover carrying with the energy transmitter is capable of loitering around the resonator, while the magnetic sensors on the receptors can be simultaneously charged according to energy-on-demand.
Joint effect of composition and strain on the anomalous transport properties of LaNiO3 films
Authors: Zhu Mingwei , Komissinskiy Philipp , Radetinac Aldin , Wang Zhanjie , Alff Lambert
Published: April 2015

In the present work, epitaxial LaNi1−xO3 films were grown on SrTiO3, (LaAlO3)0.3(Sr2AlTaO6)0.7, and LaAlO3 substrates by pulsed laser deposition from targets with different Ni stoichiometry. Effect of Ni content on the transport properties of LaNiO3 films was investigated under different strain states. It is found that under tensile strain the carriers in the LaNi0.98O3 films behave according to the Fermi-liquid theory, while under compressive strain an anomalous T1.5 dependence of the resistivity which does not agree with the Fermi-liquid theory is observed in the films. On the other hand, only T1.5 dependence is observed in the LaNi1.20O3 films irrespective of strain states. The results show that strain has a profound influence on the transport properties of LNO films with Ni deficiency and the effect of strain is eliminated in the LNO films with excess Ni. Combined with the XRD results, it is proposed that the change in transport behavior is closely related to the stoichiometry of the LNO films. The mechanism behind is investigated based on the intrinsic and extrinsic factors of the films under different strains.
Folded graphene nanochannels via pulsed patterning of graphene
Authors: Silvestre Ive , Barnard Arthur W. , Roberts Samantha P. , McEuen Paul L. , Lacerda Rodrigo G.
Published: April 2015

We present a resist-free patterning technique to form electrically contacted graphene nanochannels via localized burning by a pulsed white light source. The technique uses end-point detection to stop the burning process at a fixed resistance to produce channels with resistances of 10 kΩ to 100 kΩ. Folding of the graphene sheet takes place during patterning, which provides very straight edges as identified by AFM and SEM. Electrical transport measurements for the nanochannels show a non-linear behavior of the current vs source-drain voltage as the resistance goes above 20 kΩ indicating conduction tunneling effects. Electrochemical gating was performed to further electrically characterize the constrictions produced. The method described can be interesting not only for fundamental studies correlating edge folded structures with electrical transport but also as a promising path for fabricating graphene devices in situ. Additionally, this method might also be extended to create nanochannels in other 2D materials.
Crack problem for a bulk superconductor with nonsuperconducting inclusions under an electromagnetic force
Authors: Xue Feng , Gou Xiaofan
Published: April 2015

In this paper, the flux-pinning-induced elastic stress analysis considering the crack-inclusion interaction is carried out for a bulk superconductor in the magnetization process. A approximate model for the crack problem of a bulk superconductor with nonsuperconducting inclusions (particles) dispersed in a superconducting matrix is described. The crack is simulated as a continuous distribution of edge dislocations in the solution procedure. The obtained results show that, the shear modulus, inclusion-crack size, inclusion-crack distance, and also the magnetic field have obvious effects on the stress intensity factors (SIFs) at the crack tips of the superconductor.
Single-crystalline Bi2Sr2CaCu2O8+x detectors for direct detection of microwave radiation
Authors: Li M. , Winkler D. , Yurgens A.
Published: April 2015

We test radiation detectors made from single-crystalline Bi2Sr2CaCu2O8+x flakes put on oxidized Si substrates. The 100-nm-thick flakes are lithographically patterned into 4×12 μm2 large rectangles embedded in thin-film log-spiral antennas. The SiO2 layer weakens the thermal link between the flakes and the bath. Two modes of radiation detection have been observed. For a bolometric type of sensors a responsivity of ∼300 V/W and a noise equivalent power of 30 nW/Hz has been deduced at 70 K. Much more sensitive is the non-bolometric device showing characteristics similar to a Golay-type detector while being at least a thousand times faster. Making smaller (sub-μm) structures is expected to significantly improve the performance of these devices and makes them very competitive among other microwave and terahertz detectors.
Saturated N,X-Heterocyclic Carbenes (X=N, O, S, P, Si, C, and B): Stability, Nucleophilicity, and Basicity
Authors: Azizi Zahra , Ghambarian Mehdi , Rezaei Mohammad A. , Ghashghaee Mohammad
Published: April 2015

Various saturated five-membered N,X-heterocyclic carbenes (X = N, O, S, P, Si, C, and B) have been studied by ab initio and density functional theory (DFT) methods. The substitutions alter the properties of the reference carbene from the viewpoint of electronic structure, stability, nucleophilicity, and basicity. Our study shows that the oxygen containing carbene (X = O) induces the highest HOMO–LUMO energy gap (ΔEHOMO–LUMO), while carbene with X = N has the widest singlet–triplet energy difference (ΔEs–t). The nucleophilicity of the carbene derivatives increased upon replacement of C, Si, and B, with the effect of the boron substituent being more pronounced. In addition, the basicity of the structure increased for the carbene derivatives with X = C and B with the latter substitution imposing a remarkably higher effect. Moreover, the substitution of boron at the α-position of the carbene increased the nucleophilicity and basicity, while inducing a reduction in the values of ΔEs–t and ΔEHOMO–LUMO.
Membrane fusion during phage lysis
Authors: Rajaure Manoj , Berry Joel , Kongari Rohit , Cahill Jesse , Young Ry
Published: April 2015

Significance

These findings reveal that membrane fusion is integral to the most common prokaryotic cell fate, phage lysis, and constitutes an unprecedented topological mechanism for the removal of the last barrier to viral release. Moreover, membrane fusion in this context appears to be mediated entirely by the phage-encoded spanins in a compartment devoid of ATP. Thus, the mechanism of membrane fusion can be addressed in a very simple system accessible to the power of phage genetics.
Agricultural insecticides threaten surface waters at the global scale
Authors: Stehle Sebastian , Schulz Ralf
Published: April 2015

Significance

Agricultural systems are drivers of global environmental degradation. Insecticides, in particular, are highly biologically active substances that can threaten the ecological integrity of aquatic and terrestrial ecosystems. Despite widespread insecticide application to croplands worldwide, no comprehensive field data-based evaluation of their risk to global surface waters exists. Our data show, for the first time to our knowledge at the global scale, that more than 50% of detected insecticide concentrations (
n
= 11,300) exceed regulatory threshold levels. This finding indicates that surface water pollution resulting from current agricultural insecticide use constitutes an excessive threat to aquatic biodiversity. Overall, our analysis suggests that fundamental revisions of current regulatory procedures and pesticide application practices are needed to reverse the global environmental impacts of agrochemical-based high-intensity agriculture.
Enhancement of radiation effect on cancer cells by gold-pHLIP
Authors: Antosh Michael P. , Wijesinghe Dayanjali D. , Shrestha Samana , Lanou Robert , Huang Yun Hu , Hasselbacher Thomas , Fox David , Neretti Nicola , Sun Shouheng , Katenka Natallia , Cooper Leon N , Andreev Oleg A. , Reshetnyak Yana K.
Published: April 2015

Significance

Nanometer-sized gold particles are shown to increase the effectiveness of radiation in killing cancer cells. Improved radiation effectiveness allows less radiation to be used, reducing adverse effects to patients. Alternatively, more cancer killing could be possible while using current radiation doses. Here we used pH Low-Insertion Peptide (pHLIP) to tether gold nanoparticles to membranes of cancer cells. This increases their effectiveness because the radiation/particle effect is very localized. We find that pHLIP significantly increases the amount of gold particles in cancer cells, as well as the amount of cancer cell death from radiation. This methodology is promising for clinical research, as previous results show efficient targeting of gold nanoparticles to tumors by pHLIP.
Hypercholesterolemia and ApoE deficiency result in severe infection with Lyme disease and relapsing-fever
Borrelia
Authors: Toledo Alvaro , Monzón Javier D. , Coleman James L. , Garcia-Monco Juan C. , Benach Jorge L.
Published: April 2015

Significance

Elevated levels of cholesterol and other lipid abnormalities are common diseases of adults. Cholesterol is an essential nutrient for
Borrelia
. To test whether increased levels of cholesterol could affect the infection with
Borrelia
, we used two types of mice with different deficiencies in cholesterol transport that result in increased cholesterol levels and infected them with two species of
Borrelia
. Infection with the agent of Lyme disease resulted in higher severity, increased number of bacteria in the joints, and ankle swelling. The higher mortality found in infections with relapsing-fever
Borrelia
was associated with an apolipoprotein E deficiency and was independent of cholesterol levels. Elevated serum lipids are common diseases that could be a risk factor for increased severity in Lyme disease.
Heightened potency of human pluripotent stem cell lines created by transient BMP4 exposure
Authors: Yang Ying , Adachi Katsuyuki , Sheridan Megan A. , Alexenko Andrei P. , Schust Danny J. , Schulz Laura C. , Ezashi Toshihiko , Roberts R. Michael
Published: April 2015

Significance

Human ES cells (ESCs) and induced pluripotent stem cells (iPSCs) can differentiate along all the major cell lineages of the embryo proper, but there is evidence that they can also give rise to extraembryonic placental trophoblast. This observation is controversial because human ESCs (hESCs) are considered to arise from a part of the embryo that does not contribute to trophoblast. Here, we describe stable, self-renewing stem cell lines derived from hESCs and iPSCs by brief exposure to bone morphogenetic protein 4 (BMP4) that appear poised to differentiate readily along all the main developmental cell lineages, including placental trophoblast. BMP4 signaling may thus play a role in the early embryo by establishing a cell state permissive for trophoblast development.
Protection in antibody- and T cell-mediated autoimmune diseases by antiinflammatory IgG Fcs requires type II FcRs
Authors: Fiebiger Benjamin M. , Maamary Jad , Pincetic Andrew , Ravetch Jeffrey V.
Published: April 2015

Significance

IgG molecules are capable of inducing pro- and antiinflammatory responses dependent on their fragment crystallizable domain (Fc) glycan composition. Antiinflammatory responses are specifically triggered upon Fc sialylation, which decreases the binding affinity for type I Fc receptors but enhances binding to type II Fc receptors such as SIGN-R1, CD23, or human DC-SIGN. Structural analyses revealed that sialylation induces conformational changes in the Fc portion, which is a prerequisite for the selective binding to type II Fc receptors. Here we generated an Fc variant, F241A, that mimics the conformational state of sialylated Fc. F241A, even when nonsialylated, mediated protection from autoantibody- and T cell-mediated inflammation in a type II Fc receptor-dependent manner.
CDK1 substitutes for mTOR kinase to activate mitotic cap-dependent protein translation
Authors: Shuda Masahiro , Velásquez Celestino , Cheng Erdong , Cordek Daniel G. , Kwun Hyun Jin , Chang Yuan , Moore Patrick S.
Published: April 2015

Significance

Cancer cell proliferation is highly dependent on cap-dependent protein synthesis, which is generally assumed to be inhibited during mitosis. Using a viral oncoprotein that enforces mitosis, we show that CDK1 substitutes for mTOR interphase functions to phosphorylate eukaryotic initiation factor 4E-binding protein (4E-BP1) to a mitosis-specific δ isoform. Flow cytometric assays reveal that mitotic cells have high levels of inactivated 4E-BP1 and do not generally show specific loss of cap-dependent translation compared with interphase cells. This appears to be due to cyclin-dependent kinase 1 (CDK1) activity during mitosis. Mitotic cells typically represent less than 1% of all cells in bulk culture, and mitosis-arresting drugs, such as nocodazole, can directly inhibit mitotic protein translation, potentially explaining differences between our findings and previous studies showing reduced cap-dependent translation during mitosis.
MeCP2 binds to non-CG methylated DNA as neurons mature, influencing transcription and the timing of onset for Rett syndrome
Authors: Chen Lin , Chen Kaifu , Lavery Laura A. , Baker Steven Andrew , Shaw Chad A. , Li Wei , Zoghbi Huda Y.
Published: April 2015

Significance

Decades of research have not deciphered the mechanism by which methyl-CpG binding protein 2 (MeCP2) regulates transcription and why Rett symptoms manifest 1 to 2 y after birth. We hypothesized that the temporal dynamics of MeCP2 binding might provide an answer. We developed mice with an EGFP-tagged MeCP2 allele to identify high-resolution MeCP2 binding profiles in the adult mouse brain. Using genomic binding profiles, methylation maps, and mRNA deep-sequencing data, we found MeCP2 binds to non-CG methylation (mCH, not mCG) to regulate expression of genes altered in mouse models of MeCP2 disorders. These data and the parallel timing of mCH and MeCP2 postnatal accumulation suggest MeCP2 binds mCH as neurons mature to regulate gene expression, offering an explanation for the delayed onset of Rett.
The Stone Dreams scandal: the Nagorny Karabakh conflict and Armenian-Azerbaijani relations in contemporary literature
Authors: Mamedov Mikail
Published: April 2015

This article analyses the scandal that broke out in Azerbaijan after the publication ofStone Dreams, a novel by Azerbaijani writer Akram Aylisli.Stone Dreamsdepicted and condemned the persecution against the Armenian population in Baku and Sumgait in 1988-1990, as well as the early twentieth century massacre of the Armenian community in the writer’s home village, Aylis in Nakhichevan. Akram Aylisli touched on a taboo and in a context with weak civic and democratic institutions, the discussion of such traumatic events in Azerbaijan’s recent past proved unacceptable to both society and the ruling elite. This article reaches beyond contemporary debates, however, to cover earlier and less well-known works with Armenian-Azerbaijani themes such as Evgeniy Voyskunskiy’s novelMaiden Dreams, Seymur Baycan’sGugark, Maria Martirosova’sPhotos To Remember Me Byand Levon Javakhian’s short story “Kirve”. These works are reviewed here in terms of how they address issues of conflict, reconciliation and responsibility. This article underscores the importance of literary works dealing with conflict, as they usually reach a much broader audience than academic books.
Power, knowledge, and pipelines: understanding the politics of Azerbaijan’s foreign policy
Authors: Ismayilov Murad
Published: April 2015

This article examines the ways in which Azerbaijan’s energy abundance and the energy diplomacy the latter made possible—combined with inherent weaknesses attending the state’s young post-colonial polity—conditioned the limits of the desirable by which the country’s post-independence elite was guided and, as such, limited the range of directions—cognitive and spatial—in which Azerbaijan’s foreign policy evolved during the first decade following independence. The study then examines how energy-induced growth in state capacity on the one hand, and the perceived failure of the state’s previous practices to help resolve outstanding security problems on the other, coupled with the effects of a number of endogenous and exogenous shocks (particularly, the colour revolutions in Georgia and Ukraine; Kosovo’s recognition by the West; the Russia-Georgia 2008 war; global economic crisis; and Turkey’s short-lived attempt at rapprochement with Armenia) and the perceptual shifts those shockwaves worked to engender, served to broaden the spatial and conceptual boundaries within which Azerbaijan’s foreign policy practices were conceived and effected, including by virtue of the energy resources the country has got in possession. The paper concludes by tracing the particular ways in which the broadening and deepening of the country’s foreign policy practices have occurred.
Biomechanical forces promote blood development through prostaglandin E2 and the cAMP–PKA signaling axis
Authors: Diaz Miguel F. , Li Nan , Lee Hyun Jung , Adamo Luigi , Evans Siobahn M. , Willey Hannah E. , Arora Natasha , Torisawa Yu-suke , Vickers Dwayne A. , Morris Samantha A. , Naveiras Olaia , Murthy Shashi K. , Ingber Donald E. , Daley George Q. , García-Cardeña Guillermo , Wenzel Pamela L.
Published: April 2015

Blood flow promotes emergence of definitive hematopoietic stem cells (HSCs) in the developing embryo, yet the signals generated by hemodynamic forces that influence hematopoietic potential remain poorly defined. Here we show that fluid shear stress endows long-term multilineage engraftment potential upon early hematopoietic tissues at embryonic day 9.5, an embryonic stage not previously described to harbor HSCs. Effects on hematopoiesis are mediated in part by a cascade downstream of wall shear stress that involves calcium efflux and stimulation of the prostaglandin E2 (PGE2)–cyclic adenosine monophosphate (cAMP)–protein kinase A (PKA) signaling axis. Blockade of the PGE2–cAMP–PKA pathway in the aorta-gonad-mesonephros (AGM) abolished enhancement in hematopoietic activity. Furthermore, Ncx1 heartbeat mutants, as well as static cultures of AGM, exhibit lower levels of expression of prostaglandin synthases and reduced phosphorylation of the cAMP response element–binding protein (CREB). Similar to flow-exposed cultures, transient treatment of AGM with the synthetic analogue 16,16-dimethyl-PGE2 stimulates more robust engraftment of adult recipients and greater lymphoid reconstitution. These data provide one mechanism by which biomechanical forces induced by blood flow modulate hematopoietic potential.
Quantifying the Effects of Mexico's Retaliatory Tariffs on Selected U.S. Agricultural Exports
Authors: Zahniser Steven , Hertz Tom , Argoti Monica
Published: April 2015

This article estimates the trade‐reducing effects of the retaliatory import tariffs imposed by Mexico on selected U.S. agricultural products from March 2009 to October 2011 as part of the U.S.‐Mexico trucking dispute. Using an autoregressive distributed‐lag time series model of the targeted agricultural exports, we find that the tariffs reduced U.S. sales of these products to Mexico by $984 million (22%). We find no evidence that reduced exports to Mexico were offset by increased sales of these same goods to other countries. The large impact of the tariffs underscores the importance of the duty‐free provisions of the North American Free Trade Agreement, as well as the potentially high costs of retaliatory trade measures.