bluuebunny/crossref_metadata_2025 huggingface dataset:
A non-contact, thermal noise based method for the calibration of lateral deflection sensitivity in atomic force microscopy
Authors: Mullin Nic , Hobbs Jamie K.
Published: November 2014

Calibration of lateral forces and displacements has been a long standing problem in lateral force microscopies. Recently, it was shown by Wagner et al. that the thermal noise spectrum of the first torsional mode may be used to calibrate the deflection sensitivity of the detector. This method is quick, non-destructive and may be performed in situ in air or liquid. Here we make a full quantitative comparison of the lateral inverse optical lever sensitivity obtained by the lateral thermal noise method and the shape independent method developed by Anderson et al. We find that the thermal method provides accurate results for a wide variety of rectangular cantilevers, provided that the geometry of the cantilever is suitable for torsional stiffness calibration by the torsional Sader method, in-plane bending of the cantilever may be eliminated or accounted for and that any scaling of the lateral deflection signal between the measurement of the lateral thermal noise and the measurement of the lateral deflection is eliminated or corrected for. We also demonstrate that the thermal method may be used to characterize the linearity of the detector signal as a function of position, and find a deviation of less than 8% for the instrument used.
Bridging from particle to macroscopic scales in uniaxial magnetic gels
Authors: Menzel Andreas M.
Published: November 2014

Connecting the different length scales of characterization is an important, but often very tedious task for soft matter systems. Here, we carry out such a procedure for the theoretical description of anisotropic uniaxial magnetic gels. The so-far undetermined material parameters in a symmetry-based macroscopic hydrodynamic-like description are determined starting from a simplified mesoscopic particle-resolved model. This mesoscopic approach considers chain-like aggregates of magnetic particles embedded in an elastic matrix. Our procedure provides an illustrative background to the formal symmetry-based macroscopic description. There are presently other activities to connect such mesoscopic models as ours with more microscopic polymer-resolved approaches; together with these activities, our study complements a first attempt of scale-bridging from the microscopic to the macroscopic level in the characterization of magnetic gels.
Accurate rotational constant and bond lengths of hexafluorobenzene by femtosecond rotational Raman coherence spectroscopy and ab initio calculations
Authors: Den Takuya S. , Frey Hans-Martin , Leutwyler Samuel
Published: November 2014

The gas-phase rotational motion of hexafluorobenzene has been measured in real time using femtosecond (fs) time-resolved rotational Raman coherence spectroscopy (RR-RCS) at T = 100 and 295 K. This four-wave mixing method allows to probe the rotation of non-polar gas-phase molecules with fs time resolution over times up to ∼5 ns. The ground state rotational constant of hexafluorobenzene is determined as B0 = 1029.740(28) MHz (2σ uncertainty) from RR-RCS transients measured in a pulsed seeded supersonic jet, where essentially only the v = 0 state is populated. Using this B0 value, RR-RCS measurements in a room temperature gas cell give the rotational constants Bv of the five lowest-lying thermally populated vibrationally excited states ν7/8, ν9, ν11/12, ν13, and ν14/15. Their Bv constants differ from B0 by between −1.02 MHz and +2.23 MHz. Combining the B0 with the results of all-electron coupled-cluster CCSD(T) calculations of Demaison et al. [Mol. Phys. 111, 1539 (2013)] and of our own allow to determine the C-C and C-F semi-experimental equilibrium bond lengths re(C-C) = 1.3866(3) Å and re(C-F) = 1.3244(4) Å. These agree with the CCSD(T)/wCVQZ re bond lengths calculated by Demaison et al. within ±0.0005 Å. We also calculate the semi-experimental thermally averaged bond lengths rg(C-C)=1.3907(3) Å and rg(C-F)=1.3250(4) Å. These are at least ten times more accurate than two sets of experimental gas-phase electron diffraction rg bond lengths measured in the 1960s.
A predictive model of shell morphology in CdSe/CdS core/shell quantum dots
Authors: Gong Ke , Kelley David F.
Published: November 2014

Lattice mismatch in core/shell nanoparticles occurs when the core and shell materials have different lattice parameters. When there is a significant lattice mismatch, a coherent core-shell interface results in substantial lattice strain energy, which can affect the shell morphology. The shell can be of uniform thickness or can be rough, having thin and thick regions. A smooth shell minimizes the surface energy at the expense of increased lattice strain energy and a rough shell does the opposite. A quantitative treatment of the lattice strain energy in determining the shell morphology of CdSe/CdS core/shell nanoparticles is presented here. We use the inhomogeneity in hole tunneling rates through the shell to adsorbed hole acceptors to quantify the extent of shell thickness inhomogeneity. The results can be understood in terms of a model based on elastic continuum calculations, which indicate that the lattice strain energy depends on both core size and shell thickness. The model assumes thermodynamic equilibrium, i.e., that the shell morphology corresponds to a minimum total (lattice strain plus surface) energy. Comparison with the experimental results indicates that CdSe/CdS nanoparticles undergo an abrupt transition from smooth to rough shells when the total lattice strain energy exceeds about 27 eV or the strain energy density exceeds 0.59 eV/nm2. We also find that the predictions of this model are not followed for CdSe/CdS nanoparticles when the shell is deposited at very low temperature and therefore equilibrium is not established.
Turbulent mixing in a precessing sphere
Authors: Goto Susumu , Shimizu Masaki , Kawahara Genta
Published: November 2014

By numerically simulating turbulent flows at high Reynolds numbers in a precessing sphere, we propose a method to enhance the mixing of a fluid confined within a smooth cavity by its rotational motion alone. To precisely evaluate the mixing efficiency, we extend the quantification method proposed by Danckwerts [“The definition and measurement of some characteristics of mixtures,” Appl. Sci. Res. A 3, 279–296 (1952)] to the case in which only a finite number of fluid particle trajectories can be known. Our accurate numerical tracking of fluid particles in the flow, which is controlled by the Reynolds number (an indicator of the spin rate) and the Poincaré number (the precession rate), shows the following results. First, the mixing process on the time scale normalized by the spin period is independent of the Reynolds number as long as it is high enough for the flow to be developed turbulence. Second, fastest mixing is achieved under weak precession (Poincaré number ≈0.1); in such cases, perfect mixing requires only 10–15 spins of the container. Third, the power to sustain turbulence is a weakly increasing function of the Poincaré number, and the energy efficiency of the mixing is also maximized when the Poincaré number is about 0.1. Fourth, efficient mixing driven by the weak precession arises from the effective cooperation of complex large-scale flow and small-scale turbulence, which itself is sustained by the large-scale flow.
Purely non-local Hamiltonian formalism, Kohno connections and ∨-systems
Authors: Arsie Alessandro , Lorenzoni Paolo
Published: November 2014

In this paper, we extend purely non-local Hamiltonian formalism to a class of Riemannian F-manifolds, without assumptions on the semisimplicity of the product ○ or on the flatness of the connection ∇. In the flat case, we show that the recurrence relations for the principal hierarchy can be re-interpreted using a local and purely non-local Hamiltonian operators and in this case they split into two Lenard-Magri chains, one involving the even terms, the other involving the odd terms. Furthermore, we give an elementary proof that the Kohno property and the ∨-system condition are equivalent under suitable assumptions and we show how to associate a purely non-local Hamiltonian structure to any ∨-system, including degenerate ones.
Reducing acquisition times in multidimensional NMR with a time-optimized Fourier encoding algorithm
Authors: Zhang Zhiyong , Smith Pieter E. S. , Frydman Lucio
Published: November 2014

Speeding up the acquisition of multidimensional nuclear magnetic resonance (NMR) spectra is an important topic in contemporary NMR, with central roles in high-throughput investigations and analyses of marginally stable samples. A variety of fast NMR techniques have been developed, including methods based on non-uniform sampling and Hadamard encoding, that overcome the long sampling times inherent to schemes based on fast-Fourier-transform (FFT) methods. Here, we explore the potential of an alternative fast acquisition method that leverages a priori knowledge, to tailor polychromatic pulses and customized time delays for an efficient Fourier encoding of the indirect domain of an NMR experiment. By porting the encoding of the indirect-domain to the excitation process, this strategy avoids potential artifacts associated with non-uniform sampling schemes and uses a minimum number of scans equal to the number of resonances present in the indirect dimension. An added convenience is afforded by the fact that a usual 2D FFT can be used to process the generated data. Acquisitions of 2D heteronuclear correlation NMR spectra on quinine and on the anti-inflammatory drug isobutyl propionic phenolic acid illustrate the new method's performance. This method can be readily automated to deal with complex samples such as those occurring in metabolomics, in in-cell as well as in in vivo NMR applications, where speed and temporal stability are often primary concerns.
The geometry and integrability of the Suslov problem
Authors: Fernandez Oscar E. , Bloch Anthony M. , Zenkov Dmitry V.
Published: November 2014

In this paper, we discuss the integrability of a nonholonomic mechanical system—a generalized Klebsh–Tisserand case of the Suslov problem. Using the theory of Hamiltonization and the Poincaré–Hopf theorem we analyze the topology of the invariant manifolds and in particular describe their genus. We contrast the results with those for Hamiltonian systems.
Determination of dynamic surface tension and viscosity of non-Newtonian fluids from drop oscillations
Authors: Yang Lisong , Kazmierski Bethany K. , Hoath Stephen D. , Jung Sungjune , Hsiao Wen-Kai , Wang Yiwei , Berson Arganthaël , Harlen Oliver , Kapur Nik , Bain Colin D.
Published: November 2014

The oscillations of free-falling drops with size range from pl to μl have been used to measure the transient shear viscosity and the dynamic surface tension of shear-thinning fluids on the timescale of 10−5–10−2 s. The method is first validated with Newtonian fluids. For a given surface tension, the lower and upper limits for accurate measurement of the viscosity are determined as a function of drop size. The dynamic properties of two types of shear-thinning fluids with varying viscoelasticity are reported: aqueous suspensions of the antifungal drug griseofulvin and of the organic light-emitting diode material poly(3,4-ethylenedioxythiophene): polystyrene-sulphonate. In both cases, the free-falling drop retains the high-shear viscosity.
Entropic Ratchet transport of interacting active Brownian particles
Authors: Ai Bao-Quan , He Ya-Feng , Zhong Wei-Rong
Published: November 2014

Directed transport of interacting active (self-propelled) Brownian particles is numerically investigated in confined geometries (entropic barriers). The self-propelled velocity can break thermodynamical equilibrium and induce the directed transport. It is found that the interaction between active particles can greatly affect the ratchet transport. For attractive particles, on increasing the interaction strength, the average velocity first decreases to its minima, then increases, and finally decreases to zero. For repulsive particles, when the interaction is very weak, there exists a critical interaction at which the average velocity is minimal, nearly tends to zero, however, for the strong interaction, the average velocity is independent of the interaction.
The formation and stability of Petschek reconnection
Authors: Baty H. , Forbes T. G. , Priest E. R.
Published: November 2014

A combined analytical and numerical study of magnetic reconnection in two-dimensional resistive magnetohydrodynamics is carried out by using different explicit spatial variations of the resistivity. A special emphasis on the existence of stable/unstable Petschek's solutions is taken, comparing with the recent analytical model given by Forbes et al. [Phys. Plasmas 20, 052902 (2013)]. Our results show good quantitative agreement between the analytical theory and the numerical solutions for a Petschek-type solution to within an accuracy of about 10% or better. Our simulations also show that if the resistivity profile is relatively flat near the X-point, one of two possible asymmetric solutions will occur. Which solution occurs depends on small random perturbations of the initial conditions. The existence of two possible asymmetric solutions, in a system which is otherwise symmetric, constitutes an example of spontaneous symmetry breaking.
Note: Development of a volume-limited dot target for a high brightness extreme ultraviolet microplasma source
Authors: Dinh Thanh Hung , Suzuki Yuhei , Hirose Ryoichi , Hara Hiroyuki , Ohashi Hayato , Li Bowen , Dunne Padraig , O’Sullivan Gerry , Sunahara Atsushi , Higashiguchi Takeshi
Published: November 2014

We report on production of volume-limited dot targets based on electron beam lithographic and sputtering technologies for use in efficient high brightness extreme ultraviolet microplasma sources. We successfully produced cylindrical tin (Sn) targets with diameters of 10, 15, and 20 μm and a height of 150 nm. The calculated spectrum around 13.5 nm was in good agreement with that obtained experimentally.
Electronic properties of tantalum pentoxide polymorphs from first-principles calculations
Authors: Lee J. , Lu W. , Kioupakis E.
Published: November 2014

Tantalum pentoxide (Ta2O5) is extensively studied for its attractive properties in dielectric films, anti-reflection coatings, and resistive switching memory. Although various crystalline structures of tantalum pentoxide have been reported, its structural, electronic, and optical properties still remain a subject of research. We investigate the electronic and optical properties of crystalline and amorphous Ta2O5 structures using first-principles calculations based on density functional theory and the GW method. The calculated band gaps of the crystalline structures are too small to explain the experimental measurements, but the amorphous structure exhibits a strong exciton binding energy and an optical band gap (∼4 eV) in agreement with experiment. We determine the atomic orbitals that constitute the conduction band for each polymorph and analyze the dependence of the band gap on the atomic geometry. Our results establish the connection between the underlying structure and the electronic and optical properties of Ta2O5.
Experimental and theoretical identification of a high-pressure polymorph of Ga2S3 with α-Bi2Te3-type structure
Authors: Lai Xiaojing , Zhu Feng , Qin Shan , Chen Dongliang , Li Yanchun , Yang Ke , Wu Xiang
Published: November 2014

Since the discovery of α-phase Bi2Te3, Sb2Te3, and Bi2Se3 as 3D topological insulators, many experimental and theoretical studies of A2B3-type chalcogenides have been performed to search for new materials with interesting elastic and electric properties at ambient and extreme conditions. In this study, high-pressure properties of Ga2S3 have been characterized by in situ synchrotron X-ray diffraction (XRD), X-ray absorption near edge structure measurements, and Density-functional theory (DFT) calculations. At ∼16.0 GPa, a phase transition of α′-Ga2S3 (Cc and Z = 4) is observed experimentally to a new polymorph, which is indentified to be the tetradymite-type or α-Bi2Te3-type crystal structure (R3¯m and Z = 3) by laser-annealing XRD experiments and DFT calculations. The isothermal pressure-volume relationship of Ga2S3 is well described by the second-order Birch-Murnaghan equation of state with K0 = 59(2) GPa and K0′ = 4 (fixed) for the α′-Ga2S3, and K0 = 91(3) GPa, and K0′ = 4 (fixed) for the tetradymite-type phase. In addition, band gap of α′-Ga2S3 decreases on compression and the tetradymite-type Ga2S3 exhibits metallization based on DFT calculations. The pressure-induced phase transition accompanying by changes of elastic and electrical properties may give some implications to other chalcogenides under high pressure.
Extension of spatiotemporal chaos in glow discharge-semiconductor systems
Authors: Akhmet Marat , Rafatov Ismail , Fen Mehmet Onur
Published: November 2014

Generation of chaos in response systems is discovered numerically through specially designed unidirectional coupling of two glow discharge-semiconductor systems. By utilizing the auxiliary system approach, [H. D. I. Abarbanel, N. F. Rulkov, and M. M. Sushchik, Phys. Rev. E 53, 4528–4535 (1996)] it is verified that the phenomenon is not a chaos synchronization. Simulations demonstrate various aspects of the chaos appearance in both drive and response systems. Chaotic control is through the external circuit equation and governs the electrical potential on the boundary. The expandability of the theory to collectives of glow discharge systems is discussed, and this increases the potential of applications of the results. Moreover, the research completes the previous discussion of the chaos appearance in a glow discharge-semiconductor system [D. D. Šijačić U. Ebert, and I. Rafatov, Phys. Rev. E 70, 056220 (2004).].
Mueller matrix ellipsometric detection of profile asymmetry in nanoimprinted grating structures
Authors: Chen Xiuguo , Zhang Chuanwei , Liu Shiyuan , Jiang Hao , Ma Zhichao , Xu Zhimou
Published: November 2014

Mueller matrix ellipsometry (MME) is applied to detect foot-like asymmetry encountered in nanoimprint lithography (NIL) processes. We present both theoretical and experimental results which show that MME has good sensitivity to both the magnitude and direction of asymmetric profiles. The physics behind the use of MME for asymmetry detection is the breaking of electromagnetic reciprocity theorem for the zeroth-order diffraction of asymmetric gratings. We demonstrate that accurate characterization of asymmetric nanoimprinted gratings can be achieved by performing MME measurements in a conical mounting with the plane of incidence parallel to grating lines and meanwhile incorporating depolarization effects into the optical model. The comparison of MME-extracted asymmetric profile with the measurement by cross-sectional scanning electron microscopy also reveals the strong potential of this technique for in-line monitoring NIL processes, where symmetric structures are desired.
Tuning the properties of sprayed CuZnS films for fabrication of solar cell
Authors: Sreejith M. S. , Deepu D. R. , Kartha C. Sudha , Rajeevkumar K. , Vijayakumar K. P.
Published: November 2014

CuZnS is a promising material for solar cells, having mixed structure of CuxS and ZnS. In CuZnS thin films prepared by Chemical Spray Pyrolysis, it was observed that the material can be changed from n-type to p-type and electrical conductivity can be increased by 4 orders by just varying the Cu concentration. Increase in concentration of Cu also leads to decrease of band gap from 3.4 eV to 1.8 eV. Films of high concentration of Cu can be used as good absorber and Cu-poor films as buffer/window layer in solar cells. A bilayer heterojunction photovoltaic device could be fabricated using automated spray machine. Here, CuZnS was the absorber layer and In2S3 was the buffer layer. Using Ag as top electrode, J-V characteristics of the cell was recorded. For the optimum doped cell, the parameters obtained were Voc = 0.451 V, Jsc = 5.47 mA/cm2, FF = 42.2%, and η = 1.04%.
Surface dislocation nucleation controlled deformation of Au nanowires
Authors: Roos B. , Kapelle B. , Richter G. , Volkert C. A.
Published: November 2014

We investigate deformation in high quality Au nanowires under both tension and bending using in-situ transmission electron microscopy. Defect evolution is investigated during: (1) tensile deformation of 〈110〉 oriented, initially defect-free, single crystal nanowires with cross-sectional widths between 30 and 300 nm, (2) bending deformation of the same wires, and (3) tensile deformation of wires containing coherent twin boundaries along their lengths. We observe the formation of twins and stacking faults in the single crystal wires under tension, and storage of full dislocations after bending of single crystal wires and after tension of twinned wires. The stress state dependence of the deformation morphology and the formation of stacking faults and twins are not features of bulk Au, where deformation is controlled by dislocation interactions. Instead, we attribute the deformation morphologies to the surface nucleation of either leading or trailing partial dislocations, depending on the Schmid factors, which move through and exit the wires producing stacking faults or full dislocation slip. The presence of obstacles such as neutral planes or twin boundaries hinder the egress of the freshly nucleated dislocations and allow trailing and leading partial dislocations to combine and to be stored as full dislocations in the wires. We infer that the twins and stacking faults often observed in nanoscale Au specimens are not a direct size effect but the result of a size and obstacle dependent transition from dislocation interaction controlled to dislocation nucleation controlled deformation.
Selective coherent perfect absorption in metamaterials
Authors: Nie Guangyu , Shi Quanchao , Zhu Zheng , Shi Jinhui
Published: November 2014

We show multi-band coherent perfect absorption (CPA) in simple bilayered asymmetrically split ring metamaterials. The selectivity of absorption can be accomplished by separately excited electric and magnetic modes in a standing wave formed by two coherent counterpropagating beams. In particular, each CPA can be completely switched on/off by the phase of a second coherent wave. We propose a practical scheme for realizing multi-band coherent perfect absorption of 100% that is allowed to work from microwave to optical frequency.
Effect of crystal quality on performance of spin-polarized photocathode
Authors: Jin Xiuguang , Ozdol Burak , Yamamoto Masahiro , Mano Atsushi , Yamamoto Naoto , Takeda Yoshikazu
Published: November 2014

GaAs/GaAsP strain-compensated superlattices (SLs) with thickness up to 90-pair were fabricated. Transmission electron microscopy revealed the SLs are of high crystal quality and the introduced strain in SLs layers are fixed in the whole SL layers. With increasing SL pair number, the strain-compensated SLs show a less depolarization than the conventional strained SLs. In spite of the high crystal quality, the strain-compensated SLs also remain slightly depolarized with increasing SL pairs and the decrease in spin-polarization contributes to the spin relaxation time. 24-pair of GaAs/GaAsP strain-compensated SL demonstrates a maximum spin-polarization of 92% with a high quantum efficiency of 1.6%.
On the origin of remanence enhancement in exchange-uncoupled CoFe2O4-based composites
Authors: Quesada A. , Rubio-Marcos F. , Marco J. F. , Mompean F. J. , García-Hernández M. , Fernández J. F.
Published: November 2014

Abundant efforts are being devoted to the production of nanostructured composites based on ferrites where the exchange-spring mechanism yields larger energy products. However, experimental results occasionally contradict the predictions, and the origin of the phenomenology is not always thoroughly understood. Magnetic properties may eventually evolve in trends similar to that of exchange-spring magnets due to structural changes unrelated to exchange-coupling mechanisms at hard/soft interfaces. Thus, the evaluation of the possible sources of magnetic improvement is pivotal in determining and optimizing the extent of exchange-coupling in spring magnets. Here, we report the observation of remanence improvement and single-phase reversal behavior at room-temperature in CoFe2O4/FeCo composites, where the hard and soft phases are predominantly uncoupled. The results are explained in terms of the temperature evolution of the individual properties of CoFe2O4. Causes for the observation of single-phase magnetization reversal in exchange-uncoupled systems are discussed. Our results indicate that these type of phenomena must be taken into account in order to thoroughly understand the optimization required to improve the magnetic performance of CoFe2O4-based composites.
Smectic C chevrons in nanocylinders
Authors: Lefort R. , Jean F. , Noirez L. , Ndao M. , Cerclier C. V. , Morineau D.
Published: November 2014

The structure of an achiral smectic-C liquid crystal confined in nanocylinders with a planar surface anchoring is studied by small angle neutron scattering. We observe an invariant alignment of the nematic director with the pore axis, that promotes an original chevron structure with revolution symmetry.
Prepubertal male rats with high rates of germ-cell apoptosis present exacerbated rates of germ-cell apoptosis after serotonin depletion
Authors: Méndez Palacios Néstor , Escobar María Elena Ayala , Mendoza Maximino Méndez , Crispín Rubén Huerta , Andrade Octavio Guerrero , Melández Javier Hernández , Martínez Andrés Aragón
Published: November 2014

Male germ-cell apoptosis occurs naturally and can be increased by exposure to drugs and toxic chemicals. Individuals may have different rates of apoptosis and are likely to also exhibit differential sensitivity to outside influences. Previously, we reported that p-chloroamphetamine (pCA), a substance that inhibits serotonin synthesis, induced germ-cell apoptosis in prepubertal male rats. Here, we identified prepubertal rats with naturally high or low rates of germ-cell apoptosis and evaluated gene expression in both groups. Bax and Shbg mRNA levels were higher in rats with high rates of germ-cell apoptosis. Rats were then treated with pCA and the neuro-hormonal response and gene expression were evaluated. Treatment with pCA induced a reduction in serotonin concentrations but levels of sex hormones and gonadotrophins were not changed. Rats with initially high rates of germ-cell apoptosis had even higher rates of germ-cell apoptosis after treatment with pCA. In rats with high rates of germ-cell apoptosis Bax mRNA expression remained high after treatment with pCA. On the basis of category, an inverse relationship between mRNA expression of Bax and Bcl2, Bax and AR and Bax and Hsd3b2 was found. Here we provide evidence that innate levels of germ-cell apoptosis could be explained by the level of mRNA expression of genes involved with apoptosis and spermatogenesis.
Treatment of buffalo (Bubalus bubalis) donor cells with trichostatin A and 5-aza-2’-deoxycytidine alters their growth characteristics, gene expression and epigenetic status and improves the in vitro developmental competence, quality and epigenetic status of cloned embryos
Authors: Saini M. , Selokar N. L. , Agrawal H. , Singla S. K. , Chauhan M. S. , Manik R. S. , Palta P.
Published: November 2014

We examined the effects of treating buffalo skin fibroblast donor cells with trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, and 5-aza-2′-deoxycytidine (5azadC), a DNA methyltransferase (DNMT) inhibitor, on the cells and embryos produced by hand-made cloning. Treatment of donor cells with TSA or 5azadC resulted in altered expression levels of the HDAC1, DNMT1, DNMT3a, P53, CASPASE3 and CASPASE9 genes and global levels of acetylation of lysine at position 9 or 14 in histone 3 (H3K9/14ac), acetylation of lysine at position 5 in histone 4 (H4K5ac), acetylation of lysine at position 18 in histone 3 (H3K18ac) and tri-methylation of lysine at position 27 in histone 3 (H3K27me3). Moreover, global levels of DNA methylation and activity of DNMT1 and HDAC1 were decreased, while global acetylation of H3 and H3K9 was significantly increased in comparison to untreated cells. Simultaneous treatment of donor cells with TSA (50 nM) and 5azadC (7.5 nM) resulted in higher in vitro development to the blastocyst stage, reduction of the apoptotic index and the global level of H3K27 me3 and altered expression levels of HDAC1, P53, CASPASE3, CASPASE9 and DNMT3a in cloned blastocysts. Transfer of cloned embryos produced with donor cells treated with TSA led to the birth of a calf that survived for 21 days. These results show that treatment of buffalo donor cells with TSA and 5azadC improved developmental competence and quality of cloned embryos and altered their epigenetic status and gene expression, and that these beneficial effects were mediated by a reduction in DNA and histone methylation and an increase in histone acetylation in donor cells.
Association of C677T transition of the human methylenetetrahydrofolate reductase (MTHFR) gene with male infertility
Authors: Karimian Mohammad , Colagar Abasalt Hosseinzadeh
Published: November 2014

The human methylenetetrahydrofolate reductase (MTHFR) gene encodes one of the key enzymes in folate metabolism. This gene is located on chromosome 1 (1p36.3), which has 12 exons. The aim of the present study was to investigate the possible association of the two (C677T and A1298C) polymorphisms of this gene with male infertility. In a case-control study, 250 blood samples were collected from IVF centres in Sari and Babol (Iran): 118 samples were from oligospermic men and 132 were from controls. Two single nucleotide polymorphisms of the MTHFR genotype were detected using polymerase chain reaction–restriction fragment length polymorphism. There was no association found between the A1298C variant and male infertility. However, carriers of the 677T allele (CT and TT genotypes) were at a higher risk of infertility than individuals with other genotypes (odds ratio 1.84; 95% confidence interval 1.11–3.04; P = 0.0174). Structural analysis of human MTHFR flavoprotein showed that C677T transition played an important role in the change in affinity of the MTHFR–Flavin adenine dinucleotide binding site. Based on our results, we suggest that C677T transition in MTHFR may increase the risk of male infertility, and detection of the C677T polymorphism biomarker may be helpful in the screening of idiopathic male infertility.
Feeding and the salivary gland response in free-ranging yellow-winged grasshoppers (Gastrimargus musicus)
Authors: Wahida O. Nurul , Cooper Paul D.
Published: November 2014

Yellow-winged grasshoppers (Gastrimargus musicus) were captured in the field to examine the morphology and amine immunohistochemistry of their salivary glands. Fifty-eight grasshoppers were collected, with only five being males. Eight of 53 female grasshoppers had food in their crop, and the salivary glands of those insects were significantly heavier than those of grasshoppers without food in their crops. The salivary gland of the yellow-winged grasshopper was an acinar-type gland, similar to gland descriptions for other Orthoptera. The primary secretory part of acini of each gland is composed of zymogen and parietal cells. Staining patterns indicated that serotonin and dopamine could act as neurotransmitters and/or neurohormones to stimulate the glands. The pattern of staining of serotonin in the salivary gland suggested that serotonin stimulates both zymogen and parietal cells. Only the parietal cells were positively stained with dopamine. Comparing staining of glands of grasshoppers with food in their crop with the glands of grasshoppers with empty crops suggested a reduction in staining for serotonin in the latter. The differential staining pattern suggests that these amines have different roles in the salivary gland of G. musicus. The lack of difference in structure but increased mass with feeding suggests that all glands were active, but that secretion was actively occurring only in animals with the heavier glands.
Dealing with femtorisks in international relations
Authors: Frank Aaron Benjamin , Collins Margaret Goud , Levin Simon A. , Lo Andrew W. , Ramo Joshua , Dieckmann Ulf , Kremenyuk Victor , Kryazhimskiy Arkady , Linnerooth-Bayer JoAnne , Ramalingam Ben , Roy J. Stapleton , Saari Donald G. , Thurner Stefan , von Winterfeldt Detlof
Published: November 2014

The contemporary global community is increasingly interdependent and confronted with systemic risks posed by the actions and interactions of actors existing beneath the level of formal institutions, often operating outside effective governance structures. Frequently, these actors are human agents, such as rogue traders or aggressive financial innovators, terrorists, groups of dissidents, or unauthorized sources of sensitive or secret information about government or private sector activities. In other instances, influential “actors” take the form of climate change, communications technologies, or socioeconomic globalization. Although these individual forces may be small relative to state governments or international institutions, or may operate on long time scales, the changes they catalyze can pose significant challenges to the analysis and practice of international relations through the operation of complex feedbacks and interactions of individual agents and interconnected systems. We call these challenges “femtorisks,” and emphasize their importance for two reasons. First, in isolation, they may be inconsequential and semiautonomous; but when embedded in complex adaptive systems, characterized by individual agents able to change, learn from experience, and pursue their own agendas, the strategic interaction between actors can propel systems down paths of increasing, even global, instability. Second, because their influence stems from complex interactions at interfaces of multiple systems (e.g., social, financial, political, technological, ecological, etc.), femtorisks challenge standard approaches to risk assessment, as higher-order consequences cascade across the boundaries of socially constructed complex systems. We argue that new approaches to assessing and managing systemic risk in international relations are required, inspired by principles of evolutionary theory and development of resilient ecological systems.
Network dynamics of the brain and influence of the epileptic seizure onset zone
Authors: Burns Samuel P. , Santaniello Sabato , Yaffe Robert B. , Jouny Christophe C. , Crone Nathan E. , Bergey Gregory K. , Anderson William S. , Sarma Sridevi V.
Published: November 2014

Significance

In epilepsy, seizures elicit changes in the functional connectivity of the brain that shed insight into the seizures’ nature and onset zone. We investigated the brain connectivity of patients with partial epileptic seizures from continuous multiday recordings and found that (
i
) the connectivity defines a finite set of brain states, (
ii
) seizures are characterized by a consistent progression of states, and (
iii
) the seizure onset zone is isolated from the surrounding regions at seizure onset but becomes most connected toward seizure termination. Our results suggest that a finite-dimensional state space model may characterize the dynamics of the epileptic brain and ultimately help localize the seizure onset zone, which is currently done by clinicians through visual inspection of electrocorticographic recordings.
VEGF-B selectively regenerates injured peripheral neurons and restores sensory and trophic functions
Authors: Guaiquil Victor H. , Pan Zan , Karagianni Natalia , Fukuoka Shima , Alegre Gemstonn , Rosenblatt Mark I.
Published: November 2014

Significance

Peripheral nerve injury is a major neurological disorder that can cause multiple motor and sensory disturbances. In this study we found that VEGF-B can be used as a previously unidentified therapeutic for treating peripheral nerve injury. We demonstrated that VEGF-B stimulated nerve regeneration and enhanced the recovery of both tissue sensation and the ability of nerves to enhance healing of innervated tissue. The physiologic relevance of VEGF-B is demonstrated by our findings showing that mice lacking VEGF-B have impaired nerve regeneration and that nerve injury resulted in increased endogenous expression of VEGF-B. We discover that VEGF-B induces strong elongation and branching of neurons and requires specific transmembrane receptors as well as activation of a complex intracellular signaling.
Ethnic diversity deflates price bubbles
Authors: Levine Sheen S. , Apfelbaum Evan P. , Bernard Mark , Bartelt Valerie L. , Zajac Edward J. , Stark David
Published: November 2014

Significance

Markets are central to modern society, so their failures can have devastating effects. Here, we examine a prominent failure: price bubbles. We propose that bubbles are affected by ethnic homogeneity in the market and can be thwarted by diversity. Using experimental markets in Southeast Asia and North America, we find a marked difference: Market prices fit true values 58% better in diverse markets. In homogenous markets, overpricing is higher and traders’ errors are more correlated than in diverse markets. The findings suggest that price bubbles arise not only from individual errors or financial conditions, but also from the social context of decision making. Informing public discussion, our findings suggest that diversity facilitates friction that enhances deliberation and upends conformity.
Rapid climate change did not cause population collapse at the end of the European Bronze Age
Authors: Armit Ian , Swindles Graeme T. , Becker Katharina , Plunkett Gill , Blaauw Maarten
Published: November 2014

Significance

The impact of rapid climate change on humans is of contemporary global interest. Present-day debates are necessarily informed by paleoclimate studies in which climate is often assumed, without sufficient critical attention, to be the primary driver of societal change. Using new methods to analyze paleoclimatic and archeological datasets, we overturn the deterministic idea that population collapse at the end of the northwestern European Bronze Age was caused by rapid climate change. Our work demonstrates the necessity of high-precision chronologies in evaluating human responses to rapid climate change. It will be significant for geoscientists, climate change scientists, and archeologists.
Harm to others outweighs harm to self in moral decision making
Authors: Crockett Molly J. , Kurth-Nelson Zeb , Siegel Jenifer Z. , Dayan Peter , Dolan Raymond J.
Published: November 2014

Significance

Concern for the welfare of others is a key component of moral decision making and is disturbed in antisocial and criminal behavior. However, little is known about how people evaluate the costs of others’ suffering. Past studies have examined people’s judgments in hypothetical scenarios, but there is evidence that hypothetical judgments cannot accurately predict actual behavior. Here we addressed this issue by measuring how much money people will sacrifice to reduce the number of painful electric shocks delivered to either themselves or an anonymous stranger. Surprisingly, most people sacrifice more money to reduce a stranger’s pain than their own pain. This finding may help us better understand how people resolve moral dilemmas that commonly arise in medical, legal, and political decision making.
Complex two-component signaling regulates the general stress response in Alphaproteobacteria
Authors: Kaczmarczyk Andreas , Hochstrasser Ramon , Vorholt Julia A. , Francez-Charlot Anne
Published: November 2014

Significance

Bacteria possess many regulatory systems to monitor their environment and adapt their physiology accordingly. Whereas most systems sense one specific signal, the general stress response (GSR) is activated by many signals and protects cells against a wide range of adverse conditions. In Alphaproteobacteria, the GSR is controlled by the response regulator PhyR, but little is known about the upstream pathways. Here, we establish the GSR as a complex regulatory network composed of a particular family of partially redundant sensor kinases and of additional response regulators that modulate PhyR activity in
Sphingomonas melonis
. Given the broad conservation of this kinase family, it is possible that it plays a general role in the GSR in Alphaproteobacteria.
Transition from geostrophic turbulence to inertia–gravity waves in the atmospheric energy spectrum
Authors: Callies Jörn , Ferrari Raffaele , Bühler Oliver
Published: November 2014

Significance

High- and low-pressure systems, commonly referred to as synoptic systems, are the most energetic fluctuations of wind and temperature in the midlatitude troposphere. Synoptic systems are a few thousand kilometers in scale and are governed by a balance between the pressure gradient force and the Coriolis force. Observations collected near the tropopause by commercial aircraft indicate a change in dynamics at horizontal scales smaller than about 500 km. Smaller-scale fluctuations are shown to be dominated by inertia–gravity waves, waves that propagate on vertical density gradients but are influenced by Earth’s rotation.
Genomic imprinting, action, and interaction of maternal and fetal genomes
Authors: Keverne Eric B.
Published: November 2014

Mammalian viviparity (intrauterine development of the fetus) introduced a new dimension to brain development, with the fetal hypothalamus and fetal placenta developing at a time when the fetal placenta engages hypothalamic structures of the maternal generation. Such transgenerational interactions provide a basis for ensuring optimal maternalism in the next generation. This success has depended on genomic imprinting and a biased role of the matriline. Maternal methylation imprints determine parent of origin expression of genes fundamental to both placental and hypothalamic development. The matriline takes a further leading role for transgenerational reprogramming of these imprints. Developmental errors are minimized by the tight control that imprinted genes have on regulation of downstream evolutionary expanded gene families important for placental and hypothalamic development. Imprinted genes themselves have undergone purifying selection, providing a framework of stability for in utero development with most growth variance occurring postnatally. Mothers, not fathers, take the lead in the endocrinological and behavior adaptations that nurture, feed, and protect the infant. In utero coadaptive development of the placenta and hypothalamus has thus required a concomitant development to ensure male masculinization. Only placental male mammals evolved the sex determining
SRY
, which activates
Sox9
for testes formation.
SRY
is a hybrid gene of
Dgcr8
expressed in the developing placenta and
Sox3
expressed in hypothalamic development. This hybridization of genes that take their origin from the placenta and hypothalamus has enabled critical in utero timing for the development of fetal Leydig cells, and hence testosterone production for hypothalamic masculinization.
Relating influenza virus membrane fusion kinetics to stoichiometry of neutralizing antibodies at the single-particle level
Authors: Otterstrom Jason J. , Brandenburg Boerries , Koldijk Martin H. , Juraszek Jarek , Tang Chan , Mashaghi Samaneh , Kwaks Ted , Goudsmit Jaap , Vogels Ronald , Friesen Robert H. E. , van Oijen Antoine M.
Published: November 2014

Significance

We determine the number of broadly neutralizing antibodies required to inhibit influenza virus membrane fusion by simultaneously observing individual viral particles undergoing fusion and counting the number of antibodies bound to them. The viral membrane fusion process is mediated by fusion proteins whose activity is blocked through the binding of these antibodies to evolutionarily conserved epitopes. Surprisingly, the number of antibodies required for inhibition is markedly lower than the number of fusion proteins present, indicating virus neutralization does not require saturation of epitope occupancy. Overall, our results support a model of membrane fusion requiring several fusion proteins working together in a coordinated, stochastic fashion, and the inhibition of this process through disruption of fusion protein coordination.
Noise decomposition of intracellular biochemical signaling networks using nonequivalent reporters
Authors: Rhee Alex , Cheong Raymond , Levchenko Andre
Published: November 2014

Significance

In response to a uniform stimulus, biochemical networks display a high degree of variability when assayed across many individual cells. However, due to their complexity, the relative contributions of different pathways to the overall network variability are hard to evaluate and control. Here we introduce a technique allowing for “noise mapping” to be performed within such networks. By experimentally assaying three distinct tumor necrosis factor (TNF) activated transcription factors within a mathematical framework, we show how noise is distributed in the TNF-induced network, in the presence or absence of feedback. This framework is readily scalable to allow the noise decomposition of larger and more complex signaling networks, permitting further investigations into the dependence of biological noise on signaling system architecture.
Impact of circadian misalignment on energy metabolism during simulated nightshift work
Authors: McHill Andrew W. , Melanson Edward L. , Higgins Janine , Connick Elizabeth , Moehlman Thomas M. , Stothard Ellen R. , Wright Kenneth P.
Published: November 2014

Significance

Demands of modern society force many work operations into the night, when the intrinsic circadian timing system promotes sleep. Overnight shiftwork is associated with increased risk for adverse metabolic health and sleep disruption. Uncovering potential physiological mechanisms that contribute to metabolic dysregulation when work and eating occur at inappropriate circadian times is vital to the development of effective treatment strategies. In this study, healthy volunteers underwent a commonly used simulated shiftwork protocol to quantify changes in metabolic, sleep, and circadian physiology when working and eating during the night as compared with a traditional day work schedule. We demonstrate that nightshift work reduces total daily energy expenditure, representing a contributing mechanism for unwanted weight gain and obesity.
Basophil-mediated protection against gastrointestinal helminths requires IgE-induced cytokine secretion
Authors: Schwartz Christian , Turqueti-Neves Adriana , Hartmann Susanne , Yu Philipp , Nimmerjahn Falk , Voehringer David
Published: November 2014

Significance

Gastrointestinal worms (helminths) infect more than 2 billion people, and vaccines are not yet available. Helminths elicit a type 2 immune response characterized by high serum IgE levels and increased numbers of IL-4– or IL-13–secreting effector cells including Th2 cells, eosinophils, basophils, and type 2 innate lymphoid cells. We determined the mechanism by which basophils contribute to protection against secondary infections with gastrointestinal helminths. Here we demonstrate that basophils are recruited into the small intestine of infected mice and orchestrate the local type 2 immune response in this tissue. Basophil-mediated protection required the presence of IgE and the expression of activating Fc receptors and IL-4/IL-13 in basophils. These findings could help the development of new vaccination strategies against helminths.