bluuebunny/crossref_metadata_2025 huggingface dataset:
New observation and combined analysis of the Cs2g−, u+, and 1g states at the asymptotes 6S1/2 + 6P1/2 and 6S1/2 + 6P3/2
Authors: Ma Jie , Liu Wenliang , Yang Jinxin , Wu Jizhou , Sun Weiguo , Ivanov Valery S. , Skublov Alexei S. , Sovkov Vladimir B. , Dai Xingcan , Jia Suotang
Published: December 2014

We report on new observations of the photoassociation spectroscopy of ultracold cesium molecules using a highly sensitive detection technique and a combined analysis with all observed electronic states. The technique is achieved by directly modulating the frequency of the trapping lasers of a magneto-optical trap. New observations of the Cs2 0g−, 0u+, and 1g states at the asymptotes 6S1/2 + 6P1/2 and 6S1/2 + 6P3/2 are reported. The spectral range is extended to the red detuning of 112 cm−1 below the 6S1/2 + 6P3/2 dissociation limit. Dozens of vibrational levels of the ultracold Cs2 0g−, 0u+, and 1g states are observed for the first time. The available experimental binding energies of these states are analyzed simultaneously in a framework of the generalized LeRoy–Bernstein theory and the almost degenerate perturbation theory by Marinescu and Dalgarno [Phys. Rev. A: At., Mol., Opt. Phys. 52, 311 (1995)]. The unique atomic-related parameter c3 governing the dispersion forces of all the molecular states is estimated as (10.29 ± 0.05) a.u.
Single molecule transistor based nanopore for the detection of nicotine
Authors: Ray S. J.
Published: December 2014

A nanopore based detection methodology was proposed and investigated for the detection of Nicotine. This technique uses a Single Molecular Transistor working as a nanopore operational in the Coulomb Blockade regime. When the Nicotine molecule is pulled through the nanopore area surrounded by the Source(S), Drain (D), and Gate electrodes, the charge stability diagram can detect the presence of the molecule and is unique for a specific molecular structure. Due to the weak coupling between the different electrodes which is set by the nanopore size, the molecular energy states stay almost unaffected by the electrostatic environment that can be realised from the charge stability diagram. Identification of different orientation and position of the Nicotine molecule within the nanopore area can be made from specific regions of overlap between different charge states on the stability diagram that could be used as an electronic fingerprint for detection. This method could be advantageous and useful to detect the presence of Nicotine in smoke which is usually performed using chemical chromatography techniques.
Dominating wave regimes in a two-layer film flowing down a vertical wall
Authors: Çekiç G. , Sisoev G. M.
Published: December 2014

Flows of two-layer falling films are analyzed by an approximate method. Similar to other film flows, there is a non-uniqueness of steady-traveling waves as solutions of the problem. To select the wave regimes developing in two-layer films, systematic transient computations have been carried out to create a map of the attracting wave regimes which can be used to model real-life processes, for example, mass transfer of a gas between the layers or gas absorption into a two-layer film.
Giant self-biased magnetoelectric coupling characteristics of three-phase composite with end-bonding structure
Authors: Huang Dongyan , Lu Caijiang , Han Bing , Wang Xin , Li Chenxiao , Xu Changbao , Gui Junguo , Lin Chenghui
Published: December 2014

This paper develops a self-biased magnetoelectric (ME) heterostructure FeCuNbSiB/Ni-PZT-FeCuNbSiB/Ni (FN-P-FN) by bonding magnetization-graded FeCuNbSiB/Ni layers at the free ends of piezoelectric Pb(Zr,Ti)O3 (PZT) plate. By using the magnetization-graded magnetostrictive layer and end-bonding heterostructure, giant self-biased ME responses and obvious hysteresis are observed in FN-P-FN heterostructure. The experimental results show that the zero-biased ME voltage coefficient of FN-P-FN heterostructure reaches ∼183.2 (V/cm Oe), which is ∼2.1, ∼4.5, and ∼41.6 times higher than that of FeCuNbSiB/Ni/PZT, Ni-PZT-Ni, and FeCuNbSiB-PZT-FeCuNbSiB composites, respectively. The results indicate that the proposed three-phase end-bonding heterostructure shows promising applications for high-sensitivity self-biased magnetic field sensors and ME transducers.
Precise and direct method for the measurement of the torsion spring constant of the atomic force microscopy cantilevers
Authors: Jarząbek D. M.
Published: December 2014

A direct method for the evaluation of the torsional spring constants of the atomic force microscope cantilevers is presented in this paper. The method uses a nanoindenter to apply forces at the long axis of the cantilever and in the certain distance from it. The torque vs torsion relation is then evaluated by the comparison of the results of the indentations experiments at different positions on the cantilever. Next, this relation is used for the precise determination of the torsional spring constant of the cantilever. The statistical analysis shows that the standard deviation of the calibration measurements is equal to approximately 1%. Furthermore, a simple method for calibration of the photodetector’s lateral response is proposed. The overall procedure of the lateral calibration constant determination has the accuracy approximately equal to 10%.
Ribbon turbulence
Authors: Venaille Antoine , Nadeau Louis-Philippe , Vallis Geoffrey
Published: December 2014

We investigate the non-linear equilibration of a two-layer quasi-geostrophic flow in a channel with an initial eastward baroclinically unstable jet in the upper layer, paying particular attention to the role of bottom friction. In the limit of low bottom friction, classical theory of geostrophic turbulence predicts an inverse cascade of kinetic energy in the horizontal with condensation at the domain scale and barotropization in the vertical. By contrast, in the limit of large bottom friction, the flow is dominated by ribbons of high kinetic energy in the upper layer. These ribbons correspond to meandering jets separating regions of homogenized potential vorticity. We interpret these results by taking advantage of the peculiar conservation laws satisfied by this system: the dynamics can be recast in such a way that the initial eastward jet in the upper layer appears as an initial source of potential vorticity levels in the upper layer. The initial baroclinic instability leads to a turbulent flow that stirs this potential vorticity field while conserving the global distribution of potential vorticity levels. Statistical mechanical theory of the 112 layer quasi-geostrophic model predicts the formation of two regions of homogenized potential vorticity separated by a minimal interface. We explain that cascade phenomenology leads to the same result. We then show that the dynamics of the ribbons results from a competition between a tendency to reach the equilibrium state and baroclinic instability that induces meanders of the interface. These meanders intermittently break and induce potential vorticity mixing, but the interface remains sharp throughout the flow evolution. We show that for some parameter regimes, the ribbons act as a mixing barrier which prevents relaxation toward equilibrium, favouring the emergence of multiple zonal (eastward) jets.
Excellence of numerical differentiation method in calculating the coefficients of high temperature series expansion of the free energy and convergence problem of the expansion
Authors: Zhou S. , Solana J. R.
Published: December 2014

In this paper, it is shown that the numerical differentiation method in performing the coupling parameter series expansion [S. Zhou, J. Chem. Phys. 125, 144518 (2006); AIP Adv. 1, 040703 (2011)] excels at calculating the coefficients ai of hard sphere high temperature series expansion (HS-HTSE) of the free energy. Both canonical ensemble and isothermal-isobaric ensemble Monte Carlo simulations for fluid interacting through a hard sphere attractive Yukawa (HSAY) potential with extremely short ranges and at very low temperatures are performed, and the resulting two sets of data of thermodynamic properties are in excellent agreement with each other, and well qualified to be used for assessing convergence of the HS-HTSE for the HSAY fluid. Results of valuation are that (i) by referring to the results of a hard sphere square well fluid [S. Zhou, J. Chem. Phys. 139, 124111 (2013)], it is found that existence of partial sum limit of the high temperature series expansion series and consistency between the limit value and the true solution depend on both the potential shapes and temperatures considered. (ii) For the extremely short range HSAY potential, the HS-HTSE coefficients ai falls rapidly with the order i, and the HS-HTSE converges from fourth order; however, it does not converge exactly to the true solution at reduced temperatures lower than 0.5, wherein difference between the partial sum limit of the HS-HTSE series and the simulation result tends to become more evident. Something worth mentioning is that before the convergence order is reached, the preceding truncation is always improved by the succeeding one, and the fourth- and higher-order truncations give the most dependable and qualitatively always correct thermodynamic results for the HSAY fluid even at low reduced temperatures to 0.25.
Ion acoustic shocks in magneto rotating Lorentzian plasmas
Authors: Hussain S. , Akhtar N. , Hasnain H.
Published: December 2014

Ion acoustic shock structures in magnetized homogeneous dissipative Lorentzian plasma under the effects of Coriolis force are investigated. The dissipation in the plasma system is introduced via dynamic viscosity of inertial ions. The electrons are following the kappa distribution function. Korteweg-de Vries Burger (KdVB) equation is derived by using reductive perturbation technique. It is shown that spectral index, magnetic field, kinematic viscosity of ions, rotational frequency, and effective frequency have significant impact on the propagation characteristic of ion acoustic shocks in such plasma system. The numerical solution of KdVB equation is also discussed and transition from oscillatory profile to monotonic shock for different plasma parameters is investigated.
One dimensional full wave analysis of slow-to-fast mode conversion in lower hybrid frequencies
Authors: Jia Guo-Zhang , Gao Zhe
Published: December 2014

The linear conversion from the slow wave to the fast wave in the lower hybrid range of frequencies is analyzed numerically by using the set of field equations describing waves in a cold plane-stratified plasma. The equations are solved as a two-point boundary value problem, where the polarizations of each mode are set consistently in the boundary conditions. The scattering coefficients and the field patterns are obtained for various density profiles. It is shown that, for large density scale length, the results agree well with the traditional cognitions. In contrast, the reflected component and the probable transmitted-converted component from the conversion region, which are neglected in the usual calculations, become significant when the scale length is smaller than the wavelength of the mode. The inclusion of these new components will improve the accuracy of the simulated propagation and deposition for the injected rf power when the conversion process is involved within a sharp-varying density profile. Meanwhile, the accessibility of the incident slow wave for the low frequency case is also affected by the scale length of the density profile.
Verification of gyrokinetic particle simulation of current-driven instability in fusion plasmas. I. Internal kink mode
Authors: McClenaghan J. , Lin Z. , Holod I. , Deng W. , Wang Z.
Published: December 2014

The gyrokinetic toroidal code (GTC) capability has been extended for simulating internal kink instability with kinetic effects in toroidal geometry. The global simulation domain covers the magnetic axis, which is necessary for simulating current-driven instabilities. GTC simulation in the fluid limit of the kink modes in cylindrical geometry is verified by benchmarking with a magnetohydrodynamic eigenvalue code. Gyrokinetic simulations of the kink modes in the toroidal geometry find that ion kinetic effects significantly reduce the growth rate even when the banana orbit width is much smaller than the radial width of the perturbed current layer at the mode rational surface.
The origin of 2.7 eV blue luminescence band in zirconium oxide
Authors: Perevalov T. V. , Gulyaev D. V. , Aliev V. S. , Zhuravlev K. S. , Gritsenko V. A. , Yelisseyev A. P.
Published: December 2014

The luminescence spectra of non-stoichiometric zirconium oxide film series with different oxygen vacancies' concentrations show the blue photoluminescence band centered near a 2.7 eV peak. There is a broad band at 5.2 eV in the luminescence excitation spectrum for blue emission. The ab-initio quantum-chemical calculation gives a peak in the optical absorption at 5.1 eV for the oxygen vacancy in cubic ZrO2. It was concluded that the 2.7 eV blue luminescence excited near 5.2 eV in a zirconium oxide film is associated with the oxygen vacancy.
Origin of ferromagnetism in aluminum-doped TiO2 thin films: Theory and experiments
Authors: Wang Xianjie , Song Yongli , Tao L. L. , Feng J. F. , Sui Yu , Tang Jinke , Song Bo , Wang Yi , Wang Yang , Zhang Yu , Han X. F.
Published: December 2014

In this paper, we combine first-principles calculations and experiments to investigate the magnetic properties of aluminum-doped TiO2 films of rutile structure. Density-functional theory with generalized gradient approximation based calculations were carried out for three cases, where the TiO2 lattice contains oxygen vacancies VO only, an oxygen is substituted by a fluorine atom, or a Ti is substituted by an aluminum. Magnetic moments associated with the formation of Ti3+ ions are found in all cases but they couple differently resulting in different magnetic states. Al-doped samples prepared in our labs exhibit ferromagnetism at room temperature with a TC near 340 K. The experimental results are consistent with the first principles calculations, and the magnetism is associated with the VO defect electrons induced by the Al doping. The defect electron occupies nearby Ti sites giving rise to the Ti3+ moments and, at the same time, has spatially extended wavefunctions assuring overlapping between neighbors.
Solvent-induced changes in PEDOT:PSS films for organic electrochemical transistors
Authors: Zhang Shiming , Kumar Prajwal , Nouas Amel Sarah , Fontaine Laurie , Tang Hao , Cicoira Fabio
Published: December 2014

Organic electrochemical transistors based on the conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) are of interest for several bioelectronic applications. In this letter, we investigate the changes induced by immersion of PEDOT:PSS films, processed by spin coating from different mixtures, in water and other solvents of different polarities. We found that the film thickness decreases upon immersion in polar solvents, while the electrical conductivity remains unchanged. The decrease in film thickness is minimized via the addition of a cross-linking agent to the mixture used for the spin coating of the films.
Low- and high-order harmonic generation in the extended plasmas produced by laser ablation of zinc and manganese targets
Authors: Ganeev R. A. , Baba M. , Suzuki M. , Yoneya S. , Kuroda H.
Published: December 2014

The systematic studies of the harmonic generation of ultrashort laser pulses in the 5-mm-long Zn and Mn plasmas (i.e., application of nanosecond, picosecond, and femtosecond pulses for ablation, comparison of harmonic generation from atomic, ionic, and cluster-contained species of plasma, variation of plasma length, two-color pump of plasmas, etc.) are presented. The conversion efficiency of the 11th–19th harmonics generated in the Zn plasma was ∼5 × 10−5. The role of the ionic resonances of Zn near the 9th and 10th harmonics on the enhancement of harmonics is discussed. The enhancement of harmonics was also analyzed using the two-color pump of extended plasmas, which showed similar intensities of the odd and even harmonics along the whole range of generation. The harmonics up to the 107th order were demonstrated in the case of manganese plasma. The comparison of harmonic generation in the 5-mm-long and commonly used short (≤0.5 mm) plasma plumes showed the advanced properties of extended media.
High quality factor, fully switchable terahertz superconducting metasurface
Authors: Scalari G. , Maissen C. , Cibella S. , Leoni R. , Faist J.
Published: December 2014

We present a complementary THz metasurface realised with Niobium thin film which displays a quality factor Q = 54 and a fully switchable behaviour as a function of the temperature. The switching behaviour and the high quality factor are due to a careful design of the metasurface aimed at maximising the ohmic losses when the Nb is above the critical temperature and minimising the radiative coupling. The superconductor allows the operation of the cavity with high Q and the use of inductive elements with a high aspect ratio. Comparison with three dimensional finite element simulations highlights the crucial role of the inductive elements and of the kinetic inductance of the Cooper pairs in achieving the high quality factor and the high field enhancement.
Ferroelectric crystals for the low-voltage operation of surface dielectric barrier discharges
Authors: Johnson Michael J. , Go David B.
Published: December 2014

Dielectric barrier discharges (DBD) are commonly used to generate surface plasmas in atmospheric conditions due to their broad operational scope. Yet, high input voltages are typically required to breakdown atmospheric air. Ferroelectric crystals, however, can be used in place of dielectrics in order to reduce the driving voltage required to generate a DBD. Ferroelectrics are unique in that they have spontaneous polarizations that can be reversed by an applied electric field and also typically have very large relative permittivities. By using a ferroelectric with a large permittivity and small coercive fields, the applied voltage required to generate a discharge was reduced to <600 V in atmospheric air, and a visible glow and current filaments consistent with polarization switching were observed. Analysis of the discharge showed that the onset voltage follows a power law relation with its capacitance. Furthermore, poling the ferroelectric with a large DC voltage before use also reduced the onset voltage of the discharge.
Titanium-dioxide nanotube p-n homojunction diode
Authors: Alivov Yahya , Ding Yuchen , Singh Vivek , Nagpal Prashant
Published: December 2014

Application of semiconductors in functional optoelectronic devices requires precise control over their doping and formation of junction between p- and n-doped semiconductors. While doped thin films have led to several semiconductor devices, need for high-surface area nanostructured devices for photovoltaic, photoelectrochemical, and photocatalytic applications has been hindered by lack of desired doping in nanostructures. Here, we show titanium-dioxide (TiO2) nanotubes doped with nitrogen (N) and niobium (Nb) as acceptors and donors, respectively, and formation of TiO2 nanotubes p-n homojunction. This TiO2:N/TiO2:Nb homojunction showed distinct diode-like behaviour with rectification ratio of 1115 at ±5 V and exhibited good photoresponse for ultraviolet light (λ = 365 nm) with sensitivity of 0.19 A/W at reverse bias of −5 V. These results can have important implications for development of nanostructured metal-oxide solar-cells, photodiodes, LED's, photocatalysts, and photoelectrochemical devices.
Microwave conductance of aligned multiwall carbon nanotube textile sheets
Authors: Brown Brian L. , Bykova Julia S. , Howard Austin R. , Zakhidov Anvar A. , Shaner Eric A. , Lee Mark
Published: December 2014

Multiwall carbon nanotube (MWNT) sheets are a class of nanomaterial-based multifunctional textile with potentially useful microwave properties. To understand better the microwave electrodynamics, complex AC conductance measurements from 0.01 to 50 GHz were made on sheets of highly aligned MWNTs with the alignment texture both parallel and perpendicular to the microwave electric field polarization. In both orientations, the AC conductance is modeled to first order by a parallel frequency-independent conductance and capacitance with no inductive contribution. This is consistent with low-frequency diffusive Drude AC conduction up to 50 GHz, in contrast to the “universal disorder” AC conduction reported in many types of single-wall nanotube materials.
Strong correlation between oxygen vacancy and ferromagnetism in Yb-doped ZnO thin films
Authors: Li Fei , Liu Xue-Chao , Zhou Ren-Wei , Chen Hong-Ming , Zhuo Shi-Yi , Shi Er-Wei
Published: December 2014

Zn1−xYbxO (0 ≤ x ≤ 0.02) thin films have been prepared by inductively coupled plasma enhanced physical vapor deposition method. All the Yb-doped ZnO thin films show room-temperature ferromagnetism. The correlation between oxygen vacancy and magnetism in Yb-doped ZnO thin films is studied. It is found that Yb irons initially substitute for Zn sites when x ≤ 0.01 and then enter the interstitial sites of ZnO with increasing Yb concentration of x > 0.01. The ferromagnetism is induced by the coexistence of oxygen vacancy and Yb point defects. A strong correlation between oxygen vacancy and saturation magnetization is observed.
Interfacial effects on magnetic interlayer coupling between perpendicular Co/Ni multilayers across Ru spacer
Authors: Chen Shaohai , Xiao Yili , Xie W. H. , Zhang Zongzhi , Ma B. , Jin Q. Y.
Published: December 2014

The interlayer exchange coupling properties in synthetic antiferromagnetic (AF) structures based on Co/Ni perpendicular multilayers were investigated by varying the Ru spacer thickness (tRu) and the ferromagnetic (FM) layer material at the FM/Ru interfaces. Samples of two Co layers adjacent to Ru own much stronger AF coupling field (HAF) and show two HAF peaks located at tRu = 0.47 and 1.08 nm. If the interfacial Co layers are substituted by Ni, the HAF at the 1st peak decreases much more considerably, becomes lower than the 2nd one and even disappears due to strong pinhole-induced FM coupling. Such pinhole effect makes HAF of tRu < 0.85 nm remains unchanged or even decrease with decreasing temperatures. By tuning the interfacial Co layer thickness, pinhole effect has been suppressed as a result of greatly enhanced HAF, leading to a normal temperature dependence of Ruderman-Kittel-Kasuya-Yosida-type HAF even at thin tRu cases, i.e., increase in HAF with temperature decreasing.
Fabrication of uniformly dispersed nanoparticle-doped chalcogenide glass
Authors: Lu Chao , Almeida Juliana M. P. , Yao Nan , Arnold Craig
Published: December 2014

The dispersion of metallic nanoparticles within a chalcogenide glass matrix has the potential for many important applications in active and passive optical materials. However, the challenge of particle agglomeration, which can occur during traditional thin film processing, leads to materials with poor performance. Here, we report on the preparation of a uniformly dispersed Ag-nanoparticle (Ag NP)/chalcogenide glass heterogeneous material prepared through a combined laser- and solution-based process. Laser ablation of bulk silver is performed directly within an arsenic sulfide/propylamine solution resulting in the formation of Ag NPs in solution with an average particle size of less than 15 nm as determined by dynamic light scattering. The prepared solutions are fabricated into thin films using standard coating processes and are then analyzed using energy-dispersive X-ray spectroscopy and transmission electron microscopy to investigate the particle shape and size distribution. By calculating the nearest neighbor index and standard normal deviate of the nanoparticle locations inside the films, we verify that a uniformly dispersed distribution is achieved through this process.
Magneto-optical absorption in semiconducting spherical quantum dots: Influence of the dot-size, confining potential, and magnetic field
Authors: Kushwaha Manvir S.
Published: December 2014

Semiconducting quantum dots – more fancifully dubbed artificial atoms – are quasi-zero dimensional, tiny, man-made systems with charge carriers completely confined in all three dimensions. The scientific quest behind the synthesis of quantum dots is to create and control future electronic and optical nanostructures engineered through tailoring size, shape, and composition. The complete confinement – or the lack of any degree of freedom for the electrons (and/or holes) – in quantum dots limits the exploration of spatially localized elementary excitations such as plasmons to direct rather than reciprocal space. Here we embark on a thorough investigation of the magneto-optical absorption in semiconducting spherical quantum dots characterized by a confining harmonic potential and an applied magnetic field in the symmetric gauge. This is done within the framework of Bohm-Pines’ random-phase approximation that enables us to derive and discuss the full Dyson equation that takes proper account of the Coulomb interactions. As an application of our theoretical strategy, we compute various single-particle and many-particle phenomena such as the Fock-Darwin spectrum; Fermi energy; magneto-optical transitions; probability distribution; and the magneto-optical absorption in the quantum dots. It is observed that the role of an applied magnetic field on the absorption spectrum is comparable to that of a confining potential. Increasing (decreasing) the strength of the magnetic field or the confining potential is found to be analogous to shrinking (expanding) the size of the quantum dots: resulting into a blue (red) shift in the absorption spectrum. The Fermi energy diminishes with both increasing magnetic-field and dot-size; and exhibits saw-tooth-like oscillations at large values of field or dot-size. Unlike laterally confined quantum dots, both (upper and lower) magneto-optical transitions survive even in the extreme instances. However, the intra-Landau level transitions are seen to be forbidden. The spherical quantum dots have an edge over the strictly two-dimensional quantum dots in that the additional (magnetic) quantum number makes the physics richer (but complex). A deeper grasp of the Coulomb blockade, quantum coherence, and entanglement can lead to a better insight into promising applications involving lasers, detectors, storage devices, and quantum computing.
Polymeric synthetic nanoparticles for the induction of antigen-specific immunological tolerance
Authors: Maldonado Roberto A. , LaMothe Robert A. , Ferrari Joseph D. , Zhang Ai-Hong , Rossi Robert J. , Kolte Pallavi N. , Griset Aaron P. , O’Neil Conlin , Altreuter David H. , Browning Erica , Johnston Lloyd , Farokhzad Omid C. , Langer Robert , Scott David W. , von Andrian Ulrich H. , Kishimoto Takashi Kei
Published: December 2014

Significance

Synthetic nanoparticles containing either protein or peptide antigen and the immunosuppressant rapamycin are capable of inducing durable and specific resistance to mounting immune responses toward the antigen. This immunological tolerance operates on lymphocytes even after multiple immunogenic challenges with the antigen and adding enhancers of immune responses (adjuvants). As a result, the animals treated with these tolerogenic nanoparticles (tNPs) show reduced allergic hypersensitivity disorders, protection from disease relapse in a model of multiple sclerosis, and prevention of inhibitory antidrug antibody responses in an animal model of hemophilia A. These results show the potential for nanocarriers to modify the immunoreactivity of a given molecule by providing tolerogenic instructions to the immune system, thereby preventing or reversing pathological and neutralizing immune responses.
Cohort of birth modifies the association between FTO genotype and BMI
Authors: Rosenquist James Niels , Lehrer Steven F. , O’Malley A. James , Zaslavsky Alan M. , Smoller Jordan W. , Christakis Nicholas A.
Published: December 2014

Significance

Our finding of a significant gene-by-birth-cohort interaction adds a previously unidentified dimension to gene-by-environment interaction research, suggesting that global changes in the environment over time can modify the penetrance of genetic risk factors for diverse phenotypes. This result also suggests that presence (or absence) of a genotype–phenotype correlation may depend on the period of time study subjects were born in, or the historical moment researchers conduct their investigations.
Warfare and reproductive success in a tribal population
Authors: Glowacki Luke , Wrangham Richard
Published: December 2014

Significance

The reasons why warriors in small-scale societies participate in war are poorly understood. Evolutionary anthropologists have argued that individuals can benefit from participating in warfare despite the risks they face. Unfortunately, field data to evaluate this hypothesis are exceedingly rare. Here we present the first quantitative study on warfare and reproductive success among a pastoralist population. Participation in warfare for elders is associated with a greater number of wives and children. Ethnography suggests this result is because greater warriorship gives men increased access to bridewealth over the life course. Our results appear to apply to similar pastoralist populations and provide support for the expectation that warriors in small-scale societies benefit from participating in warfare.
Antiviral immunity of
Anopheles gambiae
is highly compartmentalized, with distinct roles for RNA interference and gut microbiota
Authors: Carissimo Guillaume , Pondeville Emilie , McFarlane Melanie , Dietrich Isabelle , Mitri Christian , Bischoff Emmanuel , Antoniewski Christophe , Bourgouin Catherine , Failloux Anna-Bella , Kohl Alain , Vernick Kenneth D.
Published: December 2014

Significance

It is important to understand antiviral mechanisms in potential new arbovirus vectors, such as
Anopheles
mosquitoes, in order to assess risks associated with arbovirus spread. Using an arbovirus naturally transmitted by
Anopheles
, we find that important immune mechanisms involved in the first bottleneck to
Anopheles
infection, the midgut, have distinct effects on arbovirus or malaria. This result is, to our knowledge, the first concrete evidence of protection tradeoffs for different human pathogens in a human disease vector, and it suggests that design of genetically immune-modified mosquitoes could result in unexpected outcomes. These results also indicate that different mosquito tissues display distinct antiviral protection that probably imposes divergent selection pressures upon viral replication during different stages of the infection.
Cryptic carbon and sulfur cycling between surface ocean plankton
Authors: Durham Bryndan P. , Sharma Shalabh , Luo Haiwei , Smith Christa B. , Amin Shady A. , Bender Sara J. , Dearth Stephen P. , Van Mooy Benjamin A. S. , Campagna Shawn R. , Kujawinski Elizabeth B. , Armbrust E. Virginia , Moran Mary Ann
Published: December 2014

Significance

In the surface ocean, organic matter released by phytoplankton and degraded by heterotrophic bacteria is a key step in the carbon cycle. Compounds important in this trophic link are poorly known, in part because of the thousands of chemicals making up marine dissolved organic matter. We cocultured a Roseobacter clade bacterium with the diatom
Thalassiosira pseudonana
and used gene expression changes to assay for compounds passed to the bacterium. A C
3
-sulfonate with no previously known role in the microbial food web was identified and subsequently shown to be an abundant diatom metabolite and actively cycling compound in seawater. This work identifies a missing component of the marine carbon and sulfur cycles.
Inducible RNAi in vivo reveals that the transcription factor BATF is required to initiate but not maintain CD8
+
T-cell effector differentiation
Authors: Godec Jernej , Cowley Glenn S. , Barnitz R. Anthony , Alkan Ozan , Root David E. , Sharpe Arlene H. , Haining W. Nicholas
Published: December 2014

Significance

Effector CD8
+
T-cell differentiation is essential for protective immunity. Investigating specific genes in this process by knockdown with RNAi is challenging because naive T cells are refractory to viral transduction. To overcome this obstacle, we developed a novel strategy to knock down genes in naive CD8
+
T cells by creating bone marrow chimera from hematopoietic progenitors transduced with an inducible shRNA. This approach enabled inducible in vivo gene knockdown in any cell type developed from this progenitor pool. We applied this strategy to show that the transcription factor BATF is essential for initial commitment to effector differentiation but becomes dispensable by 72 h. This approach now enables the study of gene function in vivo in cells of hematopoietic origin otherwise refractory to viral transduction.
Coral host cells acidify symbiotic algal microenvironment to promote photosynthesis
Authors: Barott Katie L. , Venn Alexander A. , Perez Sidney O. , Tambutté Sylvie , Tresguerres Martin
Published: December 2014

Significance

Coral growth and calcification is supported by sugars acquired from symbiotic algae, allowing corals to thrive in otherwise nutrient-poor environments. This symbiosis depends on the coordinated exchange of compounds between partners, the mechanisms of which are poorly understood. Here we found that coral host cells acidify the microenvironment where the symbiotic algae reside using a proton pump, the V-type H
+
-ATPase (VHA), which is present in the host membrane surrounding the algae. Acidification of the algal microenvironment by VHA promotes photosynthesis, demonstrating that the coral host can actively regulate symbiont physiology. This work is an important step toward understanding how animal symbioses function and provides mechanistic models that can help understand the capacity of corals to adapt to global climate change.
Mechanism by which a recently discovered allosteric inhibitor blocks glutamine metabolism in transformed cells
Authors: Stalnecker Clint A. , Ulrich Scott M. , Li Yunxing , Ramachandran Sekar , McBrayer Mary Kate , DeBerardinis Ralph J. , Cerione Richard A. , Erickson Jon W.
Published: December 2014

Significance

The work described here was motivated by our previous discovery of a connection between Rho GTPase activation and the up-regulation of mitochondrial glutaminase C (GAC), which is responsible for satisfying the glutamine addiction of cancer cells. This connection was originally established by our identification of a lead compound, 968, for a new class of inhibitors of oncogenic transformation. Although GAC was identified as the putative target for 968, how it regulated GAC was poorly understood. Here we provide important insights into the actions of 968, through the development of novel assays for its direct binding to GAC and its effects on enzyme activity. These findings offer exciting new strategies for interfering with the metabolic reprogramming critical for malignant transformation.
Direct measurement of oxidative and nitrosative stress dynamics in
Salmonella
inside macrophages
Authors: van der Heijden Joris , Bosman Else S. , Reynolds Lisa A. , Finlay B. Brett
Published: December 2014

Significance

To date, inadequate analytical methods have severely limited our ability to understand virulence strategies used by intracellular bacterial pathogens to evade reactive oxygen species (ROS) during infection. We have developed a system that is based on redox-sensitive GFP for real-time and nondisruptive measurement of redox stress experienced by
Salmonella
inside phagocytic cells. Using this system, we directly report intrabacterial redox dynamics during
Salmonella
infection of macrophages. This biosensor, which can easily be applied to other bacteria, enables a detailed study of ROS/reactive nitrogen species (RNS) evasion strategies, even detecting differences between individual bacteria. Additionally, this technique can be used for directly measuring redox responses in different environmental conditions for many bacteria.
CTLA-4 controls follicular helper T-cell differentiation by regulating the strength of CD28 engagement
Authors: Wang Chun Jing , Heuts Frank , Ovcinnikovs Vitalijs , Wardzinski Lukasz , Bowers Chantelle , Schmidt Emily M. , Kogimtzis Alexandros , Kenefeck Rupert , Sansom David M. , Walker Lucy S. K.
Published: December 2014

Significance

The inhibitory protein cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) is recognized as a crucial regulator of autoimmunity, but its precise mechanism of action is not yet fully understood. CTLA-4 can down-regulate expression of the costimulatory ligands CD80 and CD86 on antigen presenting cells, thereby reducing T-cell CD28 engagement. Here we demonstrate that quantitative changes in the level of CD28 engagement have functional consequences for T-cell differentiation toward follicular helper T cells (TFHs). These findings link CTLA-4 control of T-cell responses with the generation of high-affinity class-switched antibody responses. This generates an advanced conceptual framework for understanding the linked nature of CTLA-4 and CD28 functions and the role of this pathway in influencing autoimmunity.
Immunological consequences of intragenus conservation ofMycobacterium tuberculosisT-cell epitopes
Authors: Lindestam Arlehamn Cecilia S. , Paul Sinu , Mele Federico , Huang Charlie , Greenbaum Jason A. , Vita Randi , Sidney John , Peters Bjoern , Sallusto Federica , Sette Alessandro
Published: December 2014

Significance

Mycobacterium tuberculosis(MTB) infection is one of the most common diseases worldwide. TheMycobacteriaare a large bacterial family that includes MTB and nontuberculous mycobacteria commonly found in the environment (NTMs). We have shown that non–MTB-infected and non–bacillus Calmette–Guerin-vaccinated individuals nevertheless react to MTB-derived sequences. This reactivity can be explained by conservation of the epitope sequence in NTMs. Thus, the widespread exposure to various species ofMycobacteriainfluences reactivity to MTB and NTMs. We identified epitopes that are found only in NTMs, allowing dissociation of MTB- versus NTM-specific reactivity. These epitopes, in conjunction with epitopes specific to latent MTB infection, will provide a novel tool to study host–pathogen dynamics in the context of the design and evaluation of MTB vaccines and diagnostics.
Oxidation-driven surface dynamics on NiAl(100)
Authors: Qin Hailang , Chen Xidong , Li Liang , Sutter Peter W. , Zhou Guangwen
Published: December 2014

Significance

Oxidation of metals involves the reaction of oxygen with the metallic substrate, requiring sources or sinks of substrate atoms. This study provides direct evidence that atomic steps serve as the sources of Al surface atoms for aluminum oxide growth in the oxidation of NiAl(100), which results in coordinated migration and bunching of steps that progressively impedes the oxide growth. Comparison with the oxidation of NiAl(110) that exhibits unimpeded oxide film growth over substrate steps suggests that whenever steps are the source of atoms used for oxide growth they limit the oxidation process; when atoms are supplied from the bulk, the oxidation rate is not limited by the motion of surface steps.
Plasmonic photonic crystals realized through DNA-programmable assembly
Authors: Park Daniel J. , Zhang Chuan , Ku Jessie C. , Zhou Yu , Schatz George C. , Mirkin Chad A.
Published: December 2014

Significance

DNA-programmable methods provide unprecedented control over the assembly of nanoparticles into complex structures, including superlattices with deliberately tailorable compositions, crystal symmetries, lattice constants, and crystal habits. In principle, such bottom-up approaches can be used to assemble interesting photonic structures, including ones containing quantum dots and metal nanoparticles. Herein we show that we can tune the interaction between light and the collective electronic modes of gold nanoparticles by independently adjusting lattice constants and gold nanoparticle diameters. This opens up exciting possibilities for tuning the interaction between light and highly organized collections of particles at the nanoscale for applications ranging from lasers to quantum electrodynamics to biosensing. The structures reported herein are the first devices to our knowledge prepared by DNA guided colloidal crystallization.
Spatiotemporal variations of seismicity before major earthquakes in the Japanese area and their relation with the epicentral locations
Authors: Sarlis Nicholas V. , Skordas Efthimios S. , Varotsos Panayiotis A. , Nagao Toshiyasu , Kamogawa Masashi , Uyeda Seiya
Published: December 2014

Significance

It was recently found that a few months before major earthquakes, the seismicity in the entire Japanese region exhibits a characteristic change. This change, however, can be identified when seismic data are analyzed in a new time domain termed “natural time.” By dividing the Japanese region into small areas, we find that some small areas show the characteristic change almost simultaneously with the large area and such small areas are clustered within a few hundred kilometers from the actual epicenter of the related major earthquake. This phenomenon may serve for forecasting the epicenter of a future major earthquake.
Controlled analysis of nanoparticle charge on mucosal and systemic antibody responses following pulmonary immunization
Authors: Fromen Catherine A. , Robbins Gregory R. , Shen Tammy W. , Kai Marc P. , Ting Jenny P. Y. , DeSimone Joseph M.
Published: December 2014

Significance

To our knowledge, no other nano-based vaccine delivery platform has directly assessed the effects of nanoparticle charge on pulmonary vaccination without affecting other physio/chemical particle characteristics and/or antigen loading. The Particle Replication in Non-Wetting Templates nanoparticle fabrication process is unique in that it allows for isolation of charge as the sole variable in these studies while maintaining all other physical and chemical parameters constant. We find that positively charged nanoparticles induce robust mucosal and systemic antibody responses following pulmonary administration, whereas negatively charged nanoparticles fail to do so. Therefore, our studies underscore the importance of considering nanoparticle charge as a critical design parameter when generating pulmonary-based vaccines and may have implications for particulate vaccination through other routes of administration.
Lunapark stabilizes nascent three-way junctions in the endoplasmic reticulum
Authors: Chen Shuliang , Desai Tanvi , McNew James A. , Gerard Patrick , Novick Peter J. , Ferro-Novick Susan
Published: December 2014

Significance

In this study, we have identified an important role of mammalian Lnp1 (mLnp1) in stabilizing nascent three-way ER junctions. When new junctions acquire mLnp1, they tend to remain stable within the ER network, whereas the nascent junctions that fail to acquire mLnp1 preferentially undergo ring closure. Our findings provide insights into the function of mLnp1.
The global distribution of diet breadth in insect herbivores
Authors: Forister Matthew L. , Novotny Vojtech , Panorska Anna K. , Baje Leontine , Basset Yves , Butterill Philip T. , Cizek Lukas , Coley Phyllis D. , Dem Francesca , Diniz Ivone R. , Drozd Pavel , Fox Mark , Glassmire Andrea E. , Hazen Rebecca , Hrcek Jan , Jahner Joshua P. , Kaman Ondrej , Kozubowski Tomasz J. , Kursar Thomas A. , Lewis Owen T. , Lill John , Marquis Robert J. , Miller Scott E. , Morais Helena C. , Murakami Masashi , Nickel Herbert , Pardikes Nicholas A. , Ricklefs Robert E. , Singer Michael S. , Smilanich Angela M. , Stireman John O. , Villamarín-Cortez Santiago , Vodka Stepan , Volf Martin , Wagner David L. , Walla Thomas , Weiblen George D. , Dyer Lee A.
Published: December 2014

Significance

Dietary specialization determines an organism’s resource base as well as impacts on host or prey species. There are important basic and applied reasons to ask why some animals have narrow diets and others are more generalized, and if different regions of the Earth support more specialized interactions. We investigated site-specific host records for more than 7,500 species of insect herbivores. Although host specialists predominate, the proportion of specialists is affected by the diversity of hosts and shifts globally, supporting predictions of more exclusive tropical interactions. These results not only affect our understanding of the ecology of food webs, but also have implications for how they respond to environmental change, as well as for ecosystem management and restoration.
Stac adaptor proteins regulate trafficking and function of muscle and neuronal L-type Ca
2+
channels
Authors: Polster Alexander , Perni Stefano , Bichraoui Hicham , Beam Kurt G.
Published: December 2014

Significance

Voltage-gated calcium channels are essential for diverse cellular functions. For example, Ca
V
1.1 channels trigger skeletal muscle contraction and Ca
V
1.2 channels regulate neural gene expression in response to neuronal activity. Thus, it is important to understand the cellular mechanisms that regulate delivery of these channels to the plasma membrane and that govern calcium movements via the membrane-inserted channels. Here we show that the cellular adapter protein “Stac3” participates in both processes. Specifically, Stac3 binds to both Ca
V
1.1 and Ca
V
1.2. This binding is essential for efficient delivery of Ca
V
1.1 to the plasma membrane, but not for Ca
V
1.2. However, binding of Stac3, or the related protein Stac2, to Ca
V
1.2 causes a dramatic slowing of inactivation, thereby increasing calcium entry via Ca
V
1.2.
Optogenetic activation of cholinergic neurons in the PPT or LDT induces REM sleep
Authors: Van Dort Christa J. , Zachs Daniel P. , Kenny Jonathan D. , Zheng Shu , Goldblum Rebecca R. , Gelwan Noah A. , Ramos Daniel M. , Nolan Michael A. , Wang Karen , Weng Feng-Ju , Lin Yingxi , Wilson Matthew A. , Brown Emery N.
Published: December 2014

Significance

Rapid eye movement (REM) sleep is a critical component of restful sleep, yet the mechanisms that control REM sleep are incompletely understood. Brainstem cholinergic neurons have been implicated in REM sleep regulation, but heterogeneous cell types in the area have made it difficult to determine the specific role of each population, leading to a debate about the importance of cholinergic neurons. Therefore, we selectively activated brainstem cholinergic neurons to determine their role in REM sleep regulation. We found that activation of cholinergic neurons during non-REM sleep increased the number of REM sleep episodes but not REM sleep duration. Our data demonstrate that brainstem cholinergic neurons are important modulators of REM sleep and clarify their role in REM sleep initiation.
Absence of Dap12 and the αvβ3 integrin causes severe osteopetrosis
Authors: Zou Wei , Teitelbaum Steven L.
Published: December 2014

In vitro, ligand occupancy of αvβ3 integrin induces phosphorylation of Dap12, which is essential for osteoclast function. Like mice deleted of only αvβ3, Dap12−/− mice exhibited a slight increase in bone mass, but Dap12−/− mice, lacking another ITAM protein, FcRγ, were severely osteopetrotic. The mechanism by which FcRγ compensates for Dap12 deficiency is unknown. We find that co-deletion of FcRγ did not exacerbate the skeletal phenotype of β3−/− mice. In contrast, β3/Dap12 double-deficient (DAP/β3−/−) mice (but not β1/Dap12 double-deficient mice) were profoundly osteopetrotic, reflecting severe osteoclast dysfunction relative to those lacking αvβ3 or Dap12 alone. Activation of OSCAR, the FcRγ co-receptor, rescued Dap12−/− but not DAP/β3−/−osteoclasts. Thus, the absence of αvβ3 precluded compensation for Dap12 deficiency by FcRγ. In keeping with this, Syk phosphorylation did not occur in OSCAR-activated DAP/β3−/− osteoclasts. Thus, FcRγ requires the osteoclast αvβ3 integrin to normalize the Dap12-deficient skeleton.