bluuebunny/crossref_metadata_2025 huggingface dataset:
Evading the strength–ductility trade-off dilemma in steel through gradient hierarchical nanotwins
Authors: Wei Yujie , Li Yongqiang , Zhu Lianchun , Liu Yao , Lei Xianqi , Wang Gang , Wu Yanxin , Mi Zhenli , Liu Jiabin , Wang Hongtao , Gao Huajian
Published: April 2014

The strength–ductility trade-off has been a long-standing dilemma in materials science. This has limited the potential of many structural materials, steels in particular. Here we report a way of enhancing the strength of twinning-induced plasticity steel at no ductility trade-off. After applying torsion to cylindrical twinning-induced plasticity steel samples to generate a gradient nanotwinned structure along the radial direction, we find that the yielding strength of the material can be doubled at no reduction in ductility. It is shown that this evasion of strength–ductility trade-off is due to the formation of a gradient hierarchical nanotwinned structure during pre-torsion and subsequent tensile deformation. A series of finite element simulations based on crystal plasticity are performed to understand why the gradient twin structure can cause strengthening and ductility retention, and how sequential torsion and tension lead to the observed hierarchical nanotwinned structure through activation of different twinning systems.
Inkjet printed superparamagnetic polymer composite hemispheres with programmed magnetic anisotropy
Authors: Ergeneman Olgaç , Peters Christian , Gullo Maurizio R. , Jacot-Descombes Loïc , Gervasoni Simone , Özkale Berna , Fatio Philipe , Cadarso Victor J. , Mastrangeli Massimo , Pané Salvador , Brugger Jürgen , Hierold Christofer , Nelson Bradley J.
Published: April 2014

We present the fabrication and characterization of large arrays of inkjet-printed superparamagnetic polymer composite (SPMPC) hemispherical microstructures.
Structure of organic solids at low temperature and high pressure
Authors: Lee Rachael , Howard Judith A. K. , Probert Michael R. , Steed Jonathan W.
Published: April 2014

This tutorial review summarises the current state of the art in low temperature and high pressure crystallography of molecular organic and coordination compounds.
Pressurized hot water flow-through extraction system scale up from the laboratory to the pilot scale
Authors: Kilpeläinen P. O. , Hautala S. S. , Byman O. O. , Tanner L. J. , Korpinen R. I. , Lillandt M. K-J. , Pranovich A. V. , Kitunen V. H. , Willför S. M. , Ilvesniemi H. S.
Published: April 2014

The scaling up of the pressurized hot water flow-through extraction system for sawdust by a factor of 6000.
The intrinsic disorder status of the human hepatitis C virus proteome
Authors: Fan Xiao , Xue Bin , Dolan Patrick T. , LaCount Douglas J. , Kurgan Lukasz , Uversky Vladimir N.
Published: April 2014

We showed that intrinsically disordered regions are common in the human hepatitis C virus proteins and possess numerous important functions.
Hierarchical interfaces induce high dielectric permittivity in nanocomposites containing TiO2@BaTiO3 nanofibers
Authors: Zhang Xin , Chen Weiwei , Wang Jianjun , Shen Yang , Gu Lin , Lin Yuanhua , Nan Ce-Wen
Published: April 2014

TiO2 nanofibers embedded with BaTiO3 nanoparticles are fused with polyvinylidene fluoride into nanocomposite films. The hierarchical interfaces in the nanofibers induce a three-fold enhancement in dielectric permittivity of the polymer nanocomposites.
A comprehensive review of the application of chalcogenide nanoparticles in polymer solar cells
Authors: Freitas Jilian N. , Gonçalves Agnaldo S. , Nogueira Ana F.
Published: April 2014

A comprehensive review of the historical background and state-of-the-art of polymer/quantum dot hybrid solar cells containing metal chalcogenides is presented.
A WS2nanosheet based sensing platform for highly sensitive detection of T4 polynucleotide kinase and its inhibitors
Authors: Ge Jia , Tang Li-Juan , Xi Qiang , Li Xi-Ping , Yu Ru-Qin , Jiang Jian-Hui , Chu Xia
Published: April 2014

A nanobiosensor was developed based on a WS2nanosheet for detection of T4 polynucleotide kinase with low interference and superior sensitivity.
Fluorine-functionalized and simultaneously reduced graphene oxide as a novel hole transporting layer for highly efficient and stable organic photovoltaic cells
Authors: Kim Su-Hyeon , Lee Cheol-Ho , Yun Jin-Mun , Noh Yong-Jin , Kim Seok-Soon , Lee Sungho , Jo Seung Mu , Joh Han-Ik , Na Seok-In
Published: April 2014

A novel solution processable hole transporting layer material, based on fluorine functionalized and simultaneously reduced graphene oxide, exhibits a similar performance and superior stability to PEDOT:PSS.
Rhodium(iii)-catalyzed formal oxidative [4 + 1] cycloaddition of benzohydroxamic acids and α-diazoesters. A facile synthesis of functionalized benzolactams
Authors: Lam Hon-Wah , Man Ka-Yi , Chan Wai-Wing , Zhou Zhongyuan , Yu Wing-Yiu
Published: April 2014

A mild and regioselective Rh(iii)-catalyzed oxidative [4 + 1] cycloaddition of benzohydroxamic acids and α-diazoesters for the synthesis of benzolactam is described.
Core–shell polysiloxane–MOF 5 microspheres as a stationary phase for gas–solid chromatographic separation
Authors: Manju Manju , Roy Prasun Kumar , Ramanan Arunachalam , Rajagopal Chitra
Published: April 2014

Core–shell poly(dimethylsiloxane) (PDMS)–MOF 5 microspheres were prepared by directed crystallization of MOF 5 on thermally stable PDMS beads.
Self-assembly of magnetically recoverable ratiometric Cu2+ fluorescent sensor and adsorbent
Authors: Lu Deli , Teng Fei , Liu Yunchang , Lu Liujia , Chen Chen , Lei Juying , Wang Lingzhi , Zhang Jinlong
Published: April 2014

A magnetically recyclable ratiometric Cu2+ fluorescent sensor based on mesoporous silica nanoparticles was fabricated through a novel one-pot self-assembly method.
Switchable fluorescent AIE-active nanoporous fibers for cyclic oil adsorption
Authors: Yuan Wei , Gu Pei-Yang , Lu Cai-Jian , Zhang Ke-Qin , Xu Qing-Feng , Lu Jian-Mei
Published: April 2014

A porous fiber of AIE-active PMMA fabricated through the electrospinning technique shows exceptional fluorescence. The green fluorescence of porous fibers can be switched off and on by the adsorption and desorption of silicon or bean oil.
A molecular level understanding of interaction between FTY720 (Fingolimod hydrochloride) and DMPC multilamellar vesicles
Authors: Swain Jitendriya , Borkar Santosh R. , Aidhen Indrapal Singh , Mishra Ashok Kumar
Published: April 2014

This work focuses on the molecular level understanding of interaction between FTY720 (Fingolimod hydrochloride) and dimyristoylphosphatidylcholine (DMPC) multilamellar vesicles (MLVs) as a drug molecule carrier by investigating the structural changes, solubilisation effect and thermotropic phase behaviour.
Mode-coupling analysis of residual stresses in colloidal glasses
Authors: Fritschi S. , Fuchs M. , Voigtmann Th.
Published: April 2014

Soft glasses produced after the cessation of shear flow exhibit persistent residual stresses. Mode coupling theory of the glass transition explains their history dependence in terms of nonequilibrium, nonlinear-response relaxation of density fluctuations.
Nanometer-scale interface engineering boosts the thermoelectric performance of n-type Ti0.4Hf0.6Ni1+zSn0.975Sb0.025 alloys
Authors: Sahoo Pranati , Liu Yuanfeng , Poudeu Pierre F. P.
Published: April 2014

The generation of nanometer-scale interfaces in Ti0.4Hf0.6Ni1+zSb0.975Sn0.025 composites induces significant reduction in their thermal conductivity leading to improved ZT.
Undecylprodigiosin conjugated monodisperse gold nanoparticles efficiently cause apoptosis in colon cancer cells in vitro
Authors: Nikodinovic-Runic Jasmina , Mojic Marija , Kang Yijin , Maksimovic-Ivanic Danijela , Mijatovic Sanja , Vasiljevic Branka , Stamenkovic Vojislav R. , Senerovic Lidija
Published: April 2014

Bacterial pigment undecylprodigiosin was conjugated to monodisperse gold nanoparticles, resulting in improved stability and cytotoxicity against colon cancer cells.
Study of the reference standard facility of rhodium-iron resistance thermometer
Authors: Yin L. , Lin P. , Qi X.
Published: April 2014

A 704 type 4He cryostat is designed and the “National (China) Temperature Working Standard Group of the ITS-90 at 1.2–24 K” have been composed. A 703 type 3He cryostat have been established and the working temperature of the “National Temperature Working Standard Group of the ITS-90 at 1.2–24 K” is extended to 0.65 K, which is the lowest limit temperature of ITS-90. The 5 rhodium-iron resistance thermometers (RIRTs) which compose the Working Standard Group have been transformed to the International Temperature Scale of 1990 (ITS-90). A set of indexing data is fitted and calculated as the indexing table of the standard facility of RIRT. 42 basis temperature points have been measured at 0.67–26.37 K. The results show that the temperature control level could reach 0.5 mK/30 min. The difference between the temperature value of the 5 RIRTs and the average is less than 1.1 mK, and the comparison measurements uncertainty is 0.95 mK.
Revisiting the adsorption of copper-phthalocyanine on Au(111) including van der Waals corrections
Authors: Lüder Johann , Eriksson Olle , Sanyal Biplab , Brena Barbara
Published: April 2014

We have studied the adsorption of copper-phthalocyanine on Au(111) by means of van der Waals corrected density functional theory using the Tkatchenko-Scheffler method. We have compared the element and site resolved adsorption distances to recent experimental normal-incident X-ray standing wave measurements. The measured adsorption distances could be reproduced within a deviation of 1% for the Cu atom, 1% for the C atoms, and 2% for the N atoms. The molecule was found to have a magnetic moment of 1 μB distributed over the Cu and the N atoms of the pyrrole ring. Simulated scanning tunnel microscopy images based on the total and on the spin-resolved differential charge densities are provided for bias voltages of −1.45 and 1.45 eV.
Pulsed laser deposition of Li–N dual acceptor in p-ZnO:(Li, N) thin film and the p-ZnO:(Li, N)/n-ZnO homojunctions on Si(100)
Authors: Yang Jing-Jing , Fang Qing-Qing , Wang Wei-Na , Wang Dan-Dan , Wang Can
Published: April 2014

This article showed the p-type ZnO thin films which were co-doped with different components of Li and N by pulsed laser deposition (PLD) on Si(111) substrates. According to Hall-effect data, the Li-N co-doped ZnO:(Li, N) exhibited stable room-temperature p-type behavior. Combining the XRD, UV-vis transmittance spectrum, and Hall-effect data, the preferable preparation condition was proposed for growing high quality p-type ZnO:(Li, N) film with comparatively low resistivity of 0.09 Ω cm and relatively high carrier concentration of 2.64 × 1017 cm−3, which were obtained at 0.1 at. % lithium composition. Furthermore, compared with the photoluminescence spectrum of ZnO:(Li) with ZnO:(Li, N) thin film, the existence of Li–N dual acceptor, which activated the acceptor in ZnO:(Li, N) thin film, was confirmed. On the basis of these, the p-ZnO:(Li, N)/n-ZnO homojunctions on Si(100) substrate was realized by PLD. All these data proved that Li-N dual acceptor would be effective when activated by PLD doping and this approach was feasible to realize the physical device homojunctions on Si substrate.
Cherenkov radiation linewidth of a Josephson vortex train
Authors: Malishevskii A. S. , Silin V. P. , Uryupin S. A.
Published: April 2014

The widths of Cherenkov radiation spectrum lines of Josephson vortex trains in extended sandwiches are determined. Conditions are determined such that the line widths owing to a finite train length are comparable to or less than the line widths owing to thermal fluctuations.
Transformation of the band spectrum of Hg-based HTSC and features of the temperature dependences of the thermoelectric power coefficient
Authors: Babych O. Y. , Boyko Ya. V.
Published: April 2014

The temperature variations of the thermoelectric power coefficients of the Hg-based high-temperature superconductors HgBa2Can−1CunO2n+2+δ (n = 1, 2, 3) with oxygen doping and cation substitutions are analyzed in terms of a narrow conduction band model. The parameters of the band spectrum in the vicinity of the Fermi level are determined and the manner in which they transform is examined. A correlation is found between the effective band width and the superconducting transition temperature Tc.
Chemical potential jump during evaporation of Bose gases
Authors: Bedrikova E. A. , Latyshev A. V.
Published: April 2014

The dependence of the chemical potential jump coefficient on the evaporation coefficient of a binary mixture is studied in the case where the evaporating component is a Bose gas with a concentration assumed to be much lower than that of the carrier gas. An analytical solution of the problem yields an expression for the chemical potential jump for the case of a constant collision frequency of the Bose gas molecules.
Performance effects of device scale and core aspect-ratio on dielectric-core circuit board transformers
Authors: Bowen David , Lee Andrew , Krafft Charles , Mayergoyz Isaak D.
Published: April 2014

Broadband dielectric-core toroidal coupling transformers are attractive alternatives to magnetic core devices due to their lower cost, lower losses, and ease of integration into already established fabrication processes. However, the performance of these transformers depends greatly on device geometry, from both inductive and capacitive effects. In this study, the inductive coupling performance of candidate designs of such transformers fabricated on printed circuit board were experimentally measured as the core aspect-ratio and turn number were varied. A coupling minimum is observed, and this is determined to be the result of leakage inductance changing linearly, and mutual inductance changing quadratically with core aspect-ratio. The relationship of these dependencies to the device geometry are discussed, as well as the trade-offs that exist when designing a device that performs away from this coupling minimum.
Stability improvement of organic light emitting diodes by the insertion of hole injection materials on the indium tin oxide substrate
Authors: Chang Jung-Hung , Liu Shang-Yi , Wu I-Wen , Chen Tsung-Chin , Liu Chia-Wei , Wu Chih-I
Published: April 2014

The degradation of organic light-emitting diodes (OLEDs) is a very complex issue, which might include interfacial charge accumulation, material diffusion, and electrical-induced chemical reaction during the operation. In this study, the origins of improvement in device stability from inserting a hole injection layer (HIL) at the indium tin oxide (ITO) anode are investigated. The results from aging single-layer devices show that leakage current increases in the case of ITO/hole transport layer contact, but this phenomenon can be prevented by inserting molybdenum oxide (MoO3) or 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN6) as an HIL. Moreover, X-ray photoemission spectroscopy suggests that the diffusion of indium atoms and active oxygen species can be impeded by introducing MoO3 or HAT-CN6 as an HIL. These results reveal that the degradation of OLEDs is related to indium and oxygen out-diffusion from the ITO substrates, and that the stability of OLEDs can be improved by impeding this diffusion with HILs.
Adaptive multiconfigurational wave functions
Authors: Evangelista Francesco A.
Published: April 2014

A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff Λ. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than Λ. The resulting Λ-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (Λ+SD-CI), which is based on a small Λ-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build Λ-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The Λ-CI and Λ+SD-CI approaches are used to compute the dissociation curve of N2 and the potential energy curves for the first three singlet states of C2. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the Λ-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu2\documentclass[12pt]{minimal}\begin{document}${\rm O}_2^{2+}$\end{document}O22+ core, illustrates an alternative use of the Λ-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.
Lithium ion diffusion in Li β-alumina single crystals measured by pulsed field gradient NMR spectroscopy
Authors: Chowdhury Mohammed Tareque , Takekawa Reiji , Iwai Yoshiki , Kuwata Naoaki , Kawamura Junichi
Published: April 2014

The lithium ion diffusion coefficient of a 93% Li β-alumina single crystal was measured for the first time using pulsed field gradient (PFG) NMR spectroscopy with two different crystal orientations. The diffusion coefficient was found to be 1.2 × 10−11 m2/s in the direction perpendicular to the c axis at room temperature. The Li ion diffusion coefficient along the c axis direction was found to be very small (6.4 × 10−13 m2/s at 333 K), which suggests that the macroscopic diffusion of the Li ion in the β-alumina crystal is mainly two-dimensional. The diffusion coefficient for the same sample was also estimated using NMR line narrowing data and impedance measurements. The impedance data show reasonable agreement with PFG-NMR data, while the line narrowing measurements provided a lower value for the diffusion coefficient. Line narrowing measurements also provided a relatively low value for the activation energy and pre-exponential factor. The temperature dependent diffusion coefficient was obtained in the temperature range 297–333 K by PFG-NMR, from which the activation energy for diffusion of the Li ion was estimated. The activation energy obtained by PFG-NMR was smaller than that obtained by impedance measurements, which suggests that thermally activated defect formation energy exists for 93% Li β-alumina single crystals. The diffusion time dependence of the diffusion coefficient was observed for the Li ion in the 93% Li β-alumina single crystal by means of PFG-NMR experiments. Motion of Li ion in fractal dimension might be a possible explanation for the observed diffusion time dependence of the diffusion coefficient in the 93% Li β–alumina system.
Point-contact spectroscopy of electron-phonon interaction in superconductors
Authors: Bobrov N. L. , Khotkevich A. V. , Kamarchuk G. V. , Chubov P. N.
Published: April 2014

The possibility to reconstruct the electron-phonon interaction (EPI) function was demonstrated for S–c–N and S–c–S point contacts using the superconducting inelastic contribution to the excess current caused by Andreev reflection processes. Superconductors with both weak (Sn, Al) and strong (Pb, In) EPI were considered. It was shown that in the latter case it is necessary to account for the elastic component of current which is related to the frequency dependence of the superconducting energy gap arising due to electron-phonon renormalization of the energy spectrum of the superconductor.
Local negative magnetic permeability and possibility of observation of breather excitations in magnetic metamaterials
Authors: Bogdan M. M. , Charkina O. V.
Published: April 2014

It is shown that the long-wave dynamics and magnetic properties of one-dimensional systems constructed of the inductively and capacitively coupled split-ring resonators are described by the regularized nonlinear dispersive Klein–Gordon equations. It is found that in such systems a high-frequency magnetic field excites dynamic solitons on a “pedestal”—stable breathers, oscillating in anti-phase with respect to the background of uniform oscillations, which means the existence of regions with a negative magnetic permeability in the system. If supplemented by a medium with negative permittivity, such a system forms a “left-handed” metamaterial in which the regions with the breather excitations are transparent to electromagnetic radiation. This makes it possible to observe them experimentally.
A study of the dynamics of penetration and trapping of magnetic flux in polycrystalline YBa2Cu3O7−x samples
Authors: Slavkin V. V. , Tishchenko E. A.
Published: April 2014

In-phase and quadrature components of the first harmonic response of polycrystalline YBa2Cu3O7−x, were measured in a dc magnetic field. For small field modulation amplitude of 0.005 Oe, in-phase component of the first harmonic response of a sample was found to be proportional to the differential magnetic susceptibility. It was found that there is no pinning of Josephson vortices in a weakly coupled medium in magnetic fields below Hc2J, where Hc2J is the upper critical field of Josephson weak links. The obtained initial magnetization curve allowed us to describe the nonlinear part of the magnetization arising due to the weak bonds in ceramics. The size of a Josephson vortex and the critical parameters Hp, Hc2J and Hc1g were evaluated.
Experimental demonstration of superdirective dielectric antenna
Authors: Krasnok Alexander E. , Filonov Dmitry S. , Simovski Constantin R. , Kivshar Yuri S. , Belov Pavel A.
Published: April 2014

We propose and demonstrate experimentally a simple approach for achieving superdirectivity of emitted radiation for electrically small antennas based on a spherical dielectric resonator with a notch excited by a dipole source. Superdirectivity is achieved without using complex antenna arrays and for a wide range of frequencies. We also demonstrate the steering effect for a subwavelength displacement of the source. Finally, unlike previously known superdirective antennas, our design has significantly smaller losses, at the operation frequency radiation efficiency attains 80%, and matching holds in the 3%-wide frequency band without any special matching technique.
Electrical and optical properties of fluid iron from compressed to expanded regime
Authors: Wang Cong , Zhang Yu-Juan , Wu Ze-Qing , Zhang Ping
Published: April 2014

Using quantum molecular dynamics simulations, we show that the electrical and optical properties of fluid iron change dramatically from compressed to expanded regime. Along isochores, the main trend of the electrical resistivity, which is in good agreement with experimental data, is found to be well reproduced by our calculations. Near low densities, where the constant volume derivative of the electrical resistivity on internal energy becomes negative, the transition of iron from the metallic to the non-metallic state takes place. The study of the optical conductivity, absorption coefficient, and Rosseland mean opacity shows that, quantum molecular dynamics combined with the Kubo-Greenwood formula provide powerful tools to explore the electrical and optical properties of fluid iron.
Electric field geometries dominate quantum transport coupling in silicon nanoring
Authors: Lee Tsung-Han , Hu Shu-Fen
Published: April 2014

Investigations on the relation between the geometries of silicon nanodevices and the quantum phenomenon they exhibit, such as the Aharonov–Bohm (AB) effect and the Coulomb blockade, were conducted. An arsenic doped silicon nanoring coupled with a nanowire by electron beam lithography was fabricated. At 1.47 K, Coulomb blockade oscillations were observed under modulation from the top gate voltage, and a periodic AB oscillation of ΔB = 0.178 T was estimated for a ring radius of 86 nm under a high sweeping magnetic field. Modulating the flat top gate and the pointed side gate was performed to cluster and separate the many electron quantum dots, which demonstrated that quantum confinement and interference effects coexisted in the doped silicon nanoring.
Grain growth from amorphous phase
Authors: Očko Miroslav , Žonja Sanja , Ivanda Mile
Published: April 2014

Time dependence of the grain growth in phosphorus doped silicon thin films deposited in situ at 530 °C was investigated. The samples were annealed at 950 °C in different time intervals. The theories, which give the tn time dependent increase of grain size, cannot fit the observed data. We derived a differential equation which describes the grain growth from amorphous phase. Our experimental results and the solution of the differential equation show the effect of grain growth stagnation and even grain growth stop. The solution also comprises all the features of the result of the Monte Carlo simulation of the grain growth of pure materials.
Surprising upper limit on the electron’s electric dipole moment
Authors: Schwarzschild Bertram M.
Published: April 2014

A new null result challenges favored expansions of particle theory’s standard model.
Geoscientists seek to save HAARP
Authors: Feder Toni
Published: April 2014

With ionospheric modification, scientists can do plasma-physics experiments that are impossible in the lab.
Dynamics of a skydiver’s epic free fall
Authors: Colino José M. , Barbero Antonio J. , Tapiador Francisco J.
Published: April 2014

In October 2012 Felix Baumgartner fell farther and faster than anyone before him. The forces he experienced during his flight can be readily analyzed, thanks to the GPS data collected during his jump.
Enforcement of γδ-lineage commitment by the pre–T-cell receptor in precursors with weak γδ-TCR signals
Authors: Zarin Payam , Wong Gladys W. , Mohtashami Mahmood , Wiest David L. , Zúñiga-Pflücker Juan Carlos
Published: April 2014

Significance

Expression of a productively rearranged T-cell receptor (TCR)-β chain induces a program of αβ T-lineage differentiation, whereas thymocytes that productively rearranged TCR-γ and TCR-δ typically give rise to γδ-lineage T cells. However, given that all three TCR gene loci simultaneously undergo gene rearrangements, the possibility exists that a developing thymocyte may express a γδ-TCR together with a TCR-β or pre-TCR complex, and it is not clear to what this outcome would give rise in terms of T-lineage differentiation. Our findings point to a striking conclusion, in that rather than transmitting signals that exclusively promote αβ-lineage commitment/differentiation, the pre-TCR can function in concert with the γδ-TCR to promote γδ commitment/differentiation, a result that supports a signal strength model of αβ/γδ-lineage choice.
T helper 17 cells play a critical pathogenic role in lung cancer
Authors: Chang Seon Hee , Mirabolfathinejad Seyedeh Golsar , Katta Harshadadevi , Cumpian Amber M. , Gong Lei , Caetano Mauricio S. , Moghaddam Seyed Javad , Dong Chen
Published: April 2014

Significance

One of the challenging problems in lung cancer is to understand how inflammation pathways influence on the development of lung cancer and to identify early immune mediators. In this study, we functionally dissect the critical events occurring at the interface between endogenously arising lung tumors and the host immune system that determine tumor progression. Our findings greatly advance our knowledge on the function of T helper 17 cells in lung cancer and help understand the mechanisms of inflammatory mediators that promote lung cancer.
Molecular mechanism for differential recognition of membrane phosphatidylserine by the immune regulatory receptor Tim4
Authors: Tietjen Gregory T. , Gong Zhiliang , Chen Chiu-Hao , Vargas Ernesto , Crooks James E. , Cao Kathleen D. , Heffern Charles T. R. , Henderson J. Michael , Meron Mati , Lin Binhua , Roux Benoît , Schlossman Mark L. , Steck Theodore L. , Lee Ka Yee C. , Adams Erin J.
Published: April 2014

Significance

Structural immunology employs static, atomic-level representations to uncover the molecular mechanisms by which immune receptors sensitively discern infection and disease. Lipid membranes, particularly those exposing phosphatidylserine lipids, are now understood to be important signals in various aspects of immune regulation. However, the dynamic nature of lipid membranes makes the standard tools of structural immunology poorly suited to these systems, leaving a large gap in our understanding. Here we implement a suite of multidisciplinary tools to demonstrate, for the first time to the authors' knowledge, a mechanism for sensitivity of an immune regulatory receptor (Tim4) to the membrane context of phosphatidylserine exposure. These findings uncover new aspects of Tim4’s recognition properties and, perhaps more significantly, provide a methodology for obtaining atomic-level detail in membrane recognition.
Heat shock protein 90 controls HIV-1 reactivation from latency
Authors: Anderson Ian , Low Jun Siong , Weston Stuart , Weinberger Michael , Zhyvoloup Alexander , Labokha Aksana A. , Corazza Gianmarco , Kitson Russell A. , Moody Christopher J. , Marcello Alessandro , Fassati Ariberto
Published: April 2014

Significance

Antiretroviral therapy cannot eradicate HIV-1 because the virus can become transcriptionally inactive in resting memory CD4+ T cells (and other cell types), which are long-lived, thus generating a reservoir undetectable by the immune system. When therapy is stopped, the latent viral reservoir is activated and HIV-1 rebounds. Our understanding of HIV-1 latency and reactivation is incomplete. Here we report that the heat shock protein 90 (Hsp90) regulates HIV-1 reactivation from latency by controlling the NF-kB pathway. Therefore Hsp90 is a key molecule linking HIV-1 reactivation from latency to CD4+ T-cell activation. Selective Hsp90 inhibitors combined with PKC-ϑ inhibitors, all in phase II clinical trials, potently suppressed HIV-1 reactivation, thus Hsp90 may be a novel target to control HIV-1 latency.
Language learners privilege structured meaning over surface frequency
Authors: Culbertson Jennifer , Adger David
Published: April 2014

Significance

How humans represent aspects of the grammar of the languages they speak is a fundamental question in psychology and linguistics. Two kinds of proposals have been made: One posits abstract structural representations, while the other takes the relevant generalizations to be stated over surface statistical regularities from data learners are exposed to. Our results, based on artificial language learning experiments, show that language learners, when confronted with a new linguistic system, systematically privilege structural similarity to their native language over surface statistical similarity. We propose that the relevant structural bias is one that prefers word order and meaning to line up in a particular way.
O-
GlcNAc reports ambient temperature and confers heat resistance on ectotherm development
Authors: Radermacher Pablo T. , Myachina Faina , Bosshardt Fritz , Pandey Rahul , Mariappa Daniel , Müller H.-Arno J. , Lehner Christian F.
Published: April 2014

Significance

Unlike in birds and mammals, cells in most other organisms live at temperatures that correspond closely to those of the environment. Change in ambient temperature is a tremendous challenge for these cells. How ectothermic cells can adjust to the complex effects of temperature change is not understood in detail. Here we demonstrate that ambient temperature correlates with the level of a particular posttranslational modification of cytoplasmic and nuclear proteins in cells of different ectotherms (fruit fly, roundworm, zebrafish). Moreover, high levels of this protein modification (
O-
GlcNAc) are shown to be important for successful development at high temperatures. Concerted temperature-dependent
O-
GlcNAcylation of a wide range of cellular proteins might therefore support the myriad adjustments required in response to temperature change.
Global dissemination of a multidrug resistant
Escherichia coli
clone
Authors: Petty Nicola K. , Ben Zakour Nouri L. , Stanton-Cook Mitchell , Skippington Elizabeth , Totsika Makrina , Forde Brian M. , Phan Minh-Duy , Gomes Moriel Danilo , Peters Kate M. , Davies Mark , Rogers Benjamin A. , Dougan Gordon , Rodriguez-Baño Jesús , Pascual Alvaro , Pitout Johann D. D. , Upton Mathew , Paterson David L. , Walsh Timothy R. , Schembri Mark A. , Beatson Scott A.
Published: April 2014

Significance

Escherichia coli
sequence type 131 (ST131) is a globally disseminated multidrug-resistant clone associated with human urinary tract and bloodstream infections. Here, we have used genome sequencing to map the temporal and spatial relationship of a large collection of
E. coli
ST131 strains isolated from six distinct geographical regions across the world. We show that
E. coli
ST131 strains are distinct from other extraintestinal pathogenic
E. coli
and arose from a single progenitor strain prior to the year 2000.
Imaging bacterial peptidoglycan with near-infrared fluorogenic azide probes
Authors: Shieh Peyton , Siegrist M. Sloan , Cullen Andrew J. , Bertozzi Carolyn R.
Published: April 2014

Significance

Bioorthogonal chemistry has created new opportunities for interrogating biomolecules in cells and organisms. Near-infrared (NIR) fluorogenic probes activated by bioorthogonal chemistry are ideal for imaging studies, as tissue penetrance is highest and background fluorescence from excess probe and endogenous biomolecules is minimized at these wavelengths. Here, we present the development and optimization of NIR fluorogenic azide probes that undergo a fluorescence enhancement of up to 48-fold upon reaction with terminal or strained alkynes. In conjunction with a new class of cyclooctyne
d
-amino acids, the NIR probes were used to image bacterial peptidoglycan (PG) without the need for cytotoxic copper catalyst or washing away excess probe. This platform should facilitate the in vivo imaging of PG in pathogenic bacteria with bioorthogonal chemistry.
Microtubule binding distinguishes dystrophin from utrophin
Authors: Belanto Joseph J. , Mader Tara L. , Eckhoff Michael D. , Strandjord Dana M. , Banks Glen B. , Gardner Melissa K. , Lowe Dawn A. , Ervasti James M.
Published: April 2014

Significance

Our in vitro analyses reveal that dystrophin, the protein absent in Duchenne muscular dystrophy patients, binds microtubules with high affinity and pauses microtubule polymerization, whereas utrophin, the autosomal homologue of dystrophin thought to mirror many known functions of dystrophin, has no activity in either assay. We also report that transgenic utrophin overexpression does not correct subsarcolemmal microtubule lattice disorganization, physical inactivity after mild exercise, or loss of torque production after in vivo eccentric contraction in dystrophin-deficient skeletal muscle. Finally, our data demonstrate that microtubule lattice disorganization contributes to the greater eccentric contraction-induced injury experienced by dystrophin-deficient skeletal muscle, demonstrating a phenotype of dystrophin deficiency that utrophin-based therapy may not be able to correct.
Differential ubiquitination and degradation of huntingtin fragments modulated by ubiquitin-protein ligase E3A
Authors: Bhat Kavita P. , Yan Sen , Wang Chuan-En , Li Shihua , Li Xiao-Jiang
Published: April 2014

Significance

Ubiquitination of misfolded proteins is an important process in a variety of age-dependent neurodegenerative diseases including Alzheimer’s disease, Parkinson disease, and Huntington disease (HD). However, we know little about how ubiquitination regulates the degradation and accumulation of misfolded proteins. By using HD knock-in mice and cultured cells, we found that the pathogenic form of the HD protein is differentially ubiquitinated via K48 and K63 in ubiquitin. K48-mediated ubiquitination promotes huntingtin (Htt) degradation while K63-mediated ubiquitination accelerates its aggregation. The K-48–mediated ubiquitination depends on Ube3a, whose expression declines in aged brain. Overexpression of Ube3a in old HD KI mouse brain can reduce mutant Htt accumulation and aggregation. The age-dependent decline in Ube3a may contribute to the late-onset neuropathology in HD.
Higher-order dangers and precisely constructed taxa in models of randomness
Authors: Pincus Steve , Singer Burton H.
Published: April 2014

Significance

The validation and construction of individual, putatively “random” infinite sequences have been longstanding problems within mathematics. We address this topic via the study of binary normal numbers, which often have been viewed as models for randomness. We show that normality exhibits a rich, multifactorial taxonomy and is hardly a single monochromatic category. Furthermore, we present a toolkit of algorithmic techniques to explicitly construct normal sequences to achieve diverse yet precisely controlled specifications, many of which (e.g., bias) display unexpected and somewhat pathologic subordinate dynamics. Moreover, we construct a normal number that exhibits pairwise bias toward repeated values and, accordingly, deduce that the evaluation of higher-order block behavior, even beyond equidistribution, is imperative in proper evaluations of “randomness.”
Chapter 3. The plausibility of approaches to syntactic alternation of Hungarian verbs
Authors: Bibok Károly
Published: April 2014

Several – lexical and constructional – approaches have been proposed in the literature to theoretically treat syntactically alternating verb classes. In this chapter I aim to assess their plausibility on the basis of Kertész and Rákosi’s (this volume, 2012) notion of plausible argumentation and present a lexical-constructional account. I argue that both my proposal in general and my analysis of Hungarian verbs of locative alternation are more plausible than either lexical or constructional accounts are separately. As for the assessment of the plausibility of lexical-constructional theory itself, another current publication of mine (Bibok 2010) should be taken into consideration. The lexical-constructional framework of syntactic alternations is supported by a much wider p-context, namely, by lexical pragmatics, which duly highlights the unavoidable interaction between lexicon and contexts.
Susceptibility to Myxobolus cerebralis among Tubifex tubifex Populations from Ten Major Drainage Basins in Colorado Where Cutthroat Trout Are Endemic
Authors: Nehring R. Barry , Lukacs P. M. , Baxa D. V. , Stinson M. E. T. , Chiaramonte L. , Wise S. K. , Poole B. , Horton A.
Published: April 2014

Establishment of Myxobolus cerebralis (Mc) resulted in declines of wild Rainbow Trout Oncorhynchus mykiss populations in streams across Colorado during the 1990s. However, the risk for establishment and spread of this parasite into high-elevation habitats occupied by native Cutthroat Trout O. clarkii was unknown. Beginning in 2003, tubificid worms were collected from all major drainages where Cutthroat Trout were endemic and were assayed by quantitative PCR to determine the occurrence and distribution of the various lineages of Tubifex tubifex (Tt) oligochaetes. Over a 5-year period, 40 groups of Tt oligochaetes collected from 27 streams, 3 natural lakes, 2 private ponds, and a reservoir were evaluated for their relative susceptibility to Mc. Exposure groups were drawn from populations of pure lineage III Tt, mixed-lineage populations where one or more of the highly resistant (lineage I) or nonsusceptible lineages (V or VI) were the dominant oligochaete and susceptible lineage III worms were the subdominant worm, or pure lineage VI Tt. Experimental replicates of 250 oligochaetes were exposed to 50 Mc myxospores per worm. The parasite amplification ratio (total triactinomyxons [TAMs] produced / total myxospore exposure) was very high among all pure lineage III Colorado exposure groups, averaging 363 compared with 8.24 among the mixed-lineage exposure groups. Lineage III oligochaetes from Mt. Whitney Hatchery in California, which served as the laboratory standard for comparative purposes, had an average parasite amplification ratio of 933 among 10 exposed replicates over a 5-year period. Lineage I oligochaetes were highly resistant to infection and did not produce any TAMs. Lineages V and VI Tt did not become infected and did not produce any TAMs. These results suggest that the risk of establishment of Mc is high for aquatic habitats in Colorado where Cutthroat Trout and lineage III Tt are sympatric.

Received April 19, 2013; accepted November 4, 2013
Genetics of a Lessepsian sprinter: the bluespotted cornetfish, Fistularia commersonii
Authors: Tenggardjaja Kimberly , Jackson Alexis , Leon Frank , Azzurro Ernesto , Golani Daniel , Bernardi Giacomo
Published: April 2014

Our current understanding of the mechanisms that lead to successful biological invasions is limited. Although local adaptation plays a central role in biological invasions, genetic studies have failed to produce a unified theory so far. The bluespotted cornetfish, a recent invader of the Mediterranean Sea from the Red Sea via the Suez Canal, provides an ideal case study to research the mechanisms of invasive genetics. Previous genetic work based on mitochondrial markers has shown the genetic diversity of the Mediterranean population was greatly reduced in comparison to the natural population in the Red Sea. In the current study, we expand upon these studies by adding mitochondrial and nuclear markers. Mitochondrial results confirm previous findings. The nuclear marker, however, does not show evidence of reduction in diversity. We interpret these results as either a differential dispersal capability in males and females, or the presence of selection on the invading Mediterranean population.
Small zeros of quadratic forms outside a union of varieties
Authors: Chan Wai Kiu , Fukshansky Lenny , Henshaw Glenn
Published: April 2014

Let

F
F

be a quadratic form in

N
≥
2

N \geq 2

variables defined on a vector space

V
⊆

K
N

V \subseteq K^N

over a global field

K
K

, and

Z

⊆

K
N

\mathcal {Z} \subseteq K^N

be a finite union of varieties defined by families of homogeneous polynomials over

K
K

. We show that if

V
∖

Z

V \setminus \mathcal {Z}

contains a nontrivial zero of

F
F

, then there exists a linearly independent collection of small-height zeros of

F
F

in

V
∖

Z

V\setminus \mathcal {Z}

, where the height bound does not depend on the height of

Z

\mathcal {Z}

, only on the degrees of its defining polynomials. As a corollary of this result, we show that there exists a small-height maximal totally isotropic subspace

W
W

of the quadratic space

(
V
,
F
)

(V,F)

such that

W
W

is not contained in 

Z

\mathcal {Z}

. Our investigation extends previous results on small zeros of quadratic forms, including Cassels’ theorem and its various generalizations. The paper also contains an appendix with two variations of Siegel’s lemma. All bounds on height are explicit.
The dynamics of fish populations at low abundance and prospects for rebuilding and recovery
Authors: Hilborn Ray , Hively Daniel J. , Jensen Olaf P. , Branch Trevor A.
Published: April 2014

Previous meta-analysis of spawner–recruit relationships suggested that depensatory behaviour is uncommon, and stocks pushed to low abundance are unlikely to suffer decreases in recruitment more severe than would be expected based on the decline in spawning stock. Using an updated database that has over 100 stocks that were depleted to less than 20% of their maximum observed stock size, we tested for depensatory behaviour in both total surplus production and recruitment and we also examined the probability of stock increase as a function of stock size and fishing pressure. The number of stocks that showed a significant improvement with depensatory models was less than that expected by chance. Hierarchical meta-analysis showed that the majority of the evidence was for no depensatory behaviour but could not rule out depensation at very low stock sizes. Stocks that are depleted to low abundance are expected to rebuild when fishing pressure is reduced if the environment has not changed but there is considerable evidence that the majority of fish stocks are impacted by changes in productivity regimes. Nevertheless, if stocks are very heavily depleted and fishing pressure is not reduced to quite low levels, the expected recovery time is both uncertain and long. Very low abundance should clearly be avoided for many reasons and the range of abundance where depensation cannot be ruled out is well below commonly adopted limit reference points.
Inclusive fitness in agriculture
Authors: Kiers E. Toby , Denison R. Ford
Published: April 2014

Trade-offs between individual fitness and the collective performance of crop and below-ground symbiont communities are common in agriculture. Plant competitiveness for light and soil resources is key to individual fitness, but higher investments in stems and roots by a plant community to compete for those resources ultimately reduce crop yields. Similarly, rhizobia and mycorrhizal fungi may increase their individual fitness by diverting resources to their own reproduction, even if they could have benefited collectively by providing their shared crop host with more nitrogen and phosphorus, respectively. Past selection for inclusive fitness (benefits to others, weighted by their relatedness) is unlikely to have favoured community performance over individual fitness. The limited evidence for kin recognition in plants and microbes changes this conclusion only slightly. We therefore argue that there is still ample opportunity for human-imposed selection to improve cooperation among crop plants and their symbionts so that they use limited resources more efficiently. This evolutionarily informed approach will require a better understanding of how interactions among crops, and interactions with their symbionts, affected their inclusive fitness in the past and what that implies for current interactions.
Helping in cooperatively breeding long-tailed tits: a test of Hamilton's rule
Authors: Hatchwell Ben J. , Gullett Philippa R. , Adams Mark J.
Published: April 2014

Inclusive fitness theory provides the conceptual framework for our current understanding of social evolution, and empirical studies suggest that kin selection is a critical process in the evolution of animal sociality. A key prediction of inclusive fitness theory is that altruistic behaviour evolves when the costs incurred by an altruist (
c
) are outweighed by the benefit to the recipient (
b
), weighted by the relatedness of altruist to recipient (
r
), i.e. Hamilton's rule
rb
>
c
. Despite its central importance in social evolution theory, there have been relatively few empirical tests of Hamilton's rule, and hardly any among cooperatively breeding vertebrates, leading some authors to question its utility. Here, we use data from a long-term study of cooperatively breeding long-tailed tits
Aegithalos caudatus
to examine whether helping behaviour satisfies Hamilton's condition for the evolution of altruism. We show that helpers are altruistic because they incur survival costs through the provision of alloparental care for offspring. However, they also accrue substantial benefits through increased survival of related breeders and offspring, and despite the low average relatedness of helpers to recipients, these benefits of helping outweigh the costs incurred. We conclude that Hamilton's rule for the evolution of altruistic helping behaviour is satisfied in this species.
Whole-Cell Patch-Clamp Recording of Recombinant Voltage-Sensitive Ca2+ Channels Heterologously Expressed in HEK-293 Cells
Authors: Gandini María A. , Sandoval Alejandro , Felix Ricardo
Published: April 2014

Several factors, including showing a high efficiency of transfection and protein production, faithful translation and processing of proteins, and possession of a small cell size, have together made human embryonic kidney 293 (HEK-293) cells a popular choice among electrophysiologists. This cell line has been extensively used to study recombinant heterooligomeric voltage-sensitive Ca2+ channels. The main reasons for this are that the properties of the channel complexes can be studied in isolation and that it is also possible to define the subunit composition of the expressed channels. This protocol provides a detailed method for the transfection of, and obtaining electrophysiological data from, HEK-293 cells transiently expressing neuronal (N-type) recombinant Ca2+ channels.