bluuebunny/crossref_metadata_2025 huggingface dataset:
Particle composition and heat capacity of high‐temperature SF6 present at constant volume: Discussion on formula expressing relationship between constant‐pressure and constant‐volume heat capacities
Authors: Yokomizu Yasunobu , Kobayashi Takanori , Matsumura Toshiro
Published: September 2015

Until now, the high‐temperature properties of SF6 have been derived as a function of T for a given constant pressure P. This was based on the adoption of T and P as gas state parameters. In contrast, this paper adopts T and the gas volume V as the gas state parameters and then evaluates the particle composition and gas pressure for high‐temperature SF6 present at a constant volume state. This evaluation is achieved by the minimization of Helmholtz free energy of the high‐temperature SF6. A further derivation for the SF6 gas at constant volume is performed to reveal the temperature dependence of the molar heat capacity CVm [J/(mol·K)] and the specific heat CVg [J/(kg·K)]. Use of the obtained CVm enabled us to discuss whether the formula CPm−CVm=Rm holds true for the high‐temperature SF6 or not, where CPm and Rm are the molar heat capacity at constant pressure and the universal gas constant, respectively. Similar discussion is also performed on the formula indicating the relation between CPg and CVg, where CPg is the specific heat at constant pressure. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Comparative study of the clinical features of patients with a tubo‐ovarian abscess and patients with severe pelvic inflammatory disease
Authors: Sordia‐Hernández Luis H , Serrano Castro Laura G. , Sordia‐Piñeyro María O , Morales Martinez Arturo , Sepulveda Orozco Mary C. , Guerrero‐Gonzalez Geraldina
Published: September 2015

Objective

To determine the clinical characteristics that indicate the presence of tubo‐ovarian abscess (TOA) among patients with severe pelvic inflammatory disease (PID).

Methods

An observational cohort study was performed from October 2011 to March 2013. The study included all patients with a diagnosis of TOA and PID admitted to a university hospital in Mexico. A complete medical history and physical examination were performed, and laboratory studies were reviewed. A logistic regression analysis was performed on variables with statistical significance.

Results

Overall, 26 patients with PID and TOA (TOA group) and 26 with PID without TOA (PID group) were included in the study. Significant differences between patients with TOA and PID were found with regard to the patients’ age (39.3 years vs 33.1 years; P = 0.04), educational level (only elementary, 13 [50%] vs 5 [19%]; P = 0.14), presentation with fever (23 [88%] vs 16 [62%]; P = 0.025), white blood cell count (21.8 × 109/L vs 14.9 × 109/L; P < 0.001), number of deliveries (2.2 vs 1.1; P = 0.01), and presence of diarrhea (16 [62%] vs 5 [19%]; P < 0.001). The triad of fever, leukocytosis, and diarrhea was positively related to the presence of TOA.

Conclusion

The triad of fever, leukocytosis, and diarrhea should alert clinicians to the possibility of TOA formation in patients with PID.
What Darkens the Greenland Ice Sheet?
Authors: Tedesco Marco , Doherty Sarah , Warren Stephen , Tranter Martyn , Stroeve Julienne , Fettweis Xavier , Alexander Patrick
Published: September 2015

Limited observational data sets and incomplete surface energy balance models constrain understanding of the driving processes for Greenland's ice sheet.
Singlet and triplet instability theorems
Authors: Yamada Tomonori , Hirata So
Published: September 2015

A useful definition of orbital degeneracy—form-degeneracy—is introduced, which is distinct from the usual energy-degeneracy: Two canonical spatial orbitals are form-degenerate when the energy expectation value in the restricted Hartree–Fock (RHF) wave function is unaltered upon a two-electron excitation from one of these orbitals to the other. Form-degenerate orbitals tend to have isomorphic electron densities and occur in the highest-occupied and lowest-unoccupied molecular orbitals (HOMOs and LUMOs) of strongly correlated systems. Here, we present a mathematical proof of the existence of a triplet instability in a real or complex RHF wave function of a finite system in the space of real or complex unrestricted Hartree–Fock wave functions when HOMO and LUMO are energy- or form-degenerate. We also show that a singlet instability always exists in a real RHF wave function of a finite system in the space of complex RHF wave functions, when HOMO and LUMO are form-degenerate, but have nonidentical electron densities, or are energy-degenerate. These theorems provide Hartree–Fock-theory-based explanations of Hund’s rule, a singlet instability in Jahn–Teller systems, biradicaloid electronic structures, and a triplet instability during some covalent bond breaking. They also suggest (but not guarantee) the spontaneous formation of a spin density wave (SDW) in a metallic solid. The stability theory underlying these theorems extended to a continuous orbital-energy spectrum proves the existence of an oscillating (nonspiral) SDW instability in one- and three-dimensional homogeneous electron gases, but only at low densities or for strong interactions.
Tin-carbon clusters and the onset of microscopic level immiscibility: Experimental and computational study
Authors: Bernstein J. , Landau A. , Zemel E. , Kolodney E.
Published: September 2015

We report the experimental observation and computational analysis of the binary tin-carbon gas phase species. These novel ionic compounds are generated by impact of C60− anions on a clean tin target at some kiloelectronvolts kinetic energies. Positive SnmCn+ (m = 1-12, 1 ≤ n ≤ 8) ions were detected mass spectrometrically following ejection from the surface. Impact induced shattering of the C60− ion followed by sub-surface penetration of the resulting atomic carbon flux forces efficient mixing between target and projectile atoms even though the two elements (Sn/C) are completely immiscible in the bulk. This approach of C60− ion beam induced synthesis can be considered as an effective way for producing novel metal-carbon species of the so-called non-carbide forming elements, thus exploring the possible onset of molecular level miscibility in these systems. Sn2C2+ was found to be the most abundant carbide cluster ion. Its instantaneous formation kinetics and its measured kinetic energy distribution while exiting the surface demonstrate a single impact formation/emission event (on the sub-ps time scale). Optimal geometries were calculated for both neutral and positively charged species using Born-Oppenheimer molecular dynamics for identifying global minima, followed by density functional theory (DFT) structure optimization and energy calculations at the coupled cluster singles, doubles and perturbative triples [CCSD(T)] level. The calculated structures reflect two distinct binding tendencies. The carbon rich species exhibit polyynic/cummulenic nature (tin end capped carbon chains) while the more stoichiometrically balanced species have larger contributions of metal-metal bonding, sometimes resulting in distinct tin and carbon moieties attached to each other (segregated structures). The Sn2Cn (n = 3–8) and Sn2Cn+ (n = 2–8) are polyynic/cummulenic while all neutral SnmCn structures (m = 3–4) could be described as small tin clusters (dimer, trimer, and tetramer, correspondingly) attached to a nearly linear carbon chain. For example, the 1:1 (Sn:C) Sn3C3 and Sn4C4 clusters are composed of all-tin triangle and rhombus, correspondingly, with a short carbon chain (C3, C4) attached on top. The cationic Sn3Cn+ (n = 1–5) and Sn4Cn+ (n = 1–4) species exhibit various intermediate geometries. Structure calculations at the CCSD(T) level are essential since the segregation effect is not as easily evident based on the most stable structures calculated by DFT alone. Dependences of bond energies (per atom) reflect the evolution of the segregation effect. The mass spectral abundances could be reasonably rationalized in terms of calculated stabilities of the cluster ions with respect to various dissociation channels.
How nanochannel confinement affects the DNA melting transition within the Poland-Scheraga model
Authors: Reiter-Schad Michaela , Werner Erik , Tegenfeldt Jonas O. , Mehlig Bernhard , Ambjörnsson Tobias
Published: September 2015

When double-stranded DNA molecules are heated, or exposed to denaturing agents, the two strands are separated. The statistical physics of this process has a long history and is commonly described in terms of the Poland-Scheraga (PS) model. Crucial to this model is the configurational entropy for a melted region (compared to the entropy of an intact region of the same size), quantified by the loop factor. In this study, we investigate how confinement affects the DNA melting transition, by using the loop factor for an ideal Gaussian chain. By subsequent numerical solutions of the PS model, we demonstrate that the melting temperature depends on the persistence lengths of single-stranded and double-stranded DNA. For realistic values of the persistence lengths, the melting temperature is predicted to decrease with decreasing channel diameter. We also demonstrate that confinement broadens the melting transition. These general findings hold for the three scenarios investigated: 1. homo-DNA, i.e., identical basepairs along the DNA molecule, 2. random sequence DNA, and 3. “real” DNA, here T4 phage DNA. We show that cases 2 and 3 in general give rise to broader transitions than case 1. Case 3 exhibits a similar phase transition as case 2 provided the random sequence DNA has the same ratio of AT to GC basepairs (A - adenine, T - thymine, G - guanine, C - cytosine). A simple analytical estimate for the shift in melting temperature is provided as a function of nanochannel diameter. For homo-DNA, we also present an analytical prediction of the melting probability as a function of temperature.
More on rotations as spin matrix polynomials
Authors: Curtright Thomas L.
Published: September 2015

Any nonsingular function of spin j matrices always reduces to a matrix polynomial of order 2j. The challenge is to find a convenient form for the coefficients of the matrix polynomial. The theory of biorthogonal systems is a useful framework to meet this challenge. Central factorial numbers play a key role in the theoretical development. Explicit polynomial coefficients for rotations expressed either as exponentials or as rational Cayley transforms are considered here. Structural features of the results are discussed and compared, and large j limits of the coefficients are examined.
Efficient Schmidt number scaling in dissipative particle dynamics
Authors: Krafnick Ryan C. , García Angel E.
Published: September 2015

Dissipative particle dynamics is a widely used mesoscale technique for the simulation of hydrodynamics (as well as immersed particles) utilizing coarse-grained molecular dynamics. While the method is capable of describing any fluid, the typical choice of the friction coefficient γ and dissipative force cutoff rc yields an unacceptably low Schmidt number Sc for the simulation of liquid water at standard temperature and pressure. There are a variety of ways to raise Sc, such as increasing γ and rc, but the relative cost of modifying each parameter (and the concomitant impact on numerical accuracy) has heretofore remained undetermined. We perform a detailed search over the parameter space, identifying the optimal strategy for the efficient and accuracy-preserving scaling of Sc, using both numerical simulations and theoretical predictions. The composite results recommend a parameter choice that leads to a speed improvement of a factor of three versus previously utilized strategies.
Normal metal tunnel junction-based superconducting quantum interference proximity transistor
Authors: D'Ambrosio Sophie , Meissner Martin , Blanc Christophe , Ronzani Alberto , Giazotto Francesco
Published: September 2015

We report the fabrication and characterization of an alternative design for a superconducting quantum interference proximity transistor (SQUIPT) based on a normal metal (N) probe. The absence of direct Josephson coupling between the proximized metal nanowire and the N probe allows us to observe the full modulation of the wire density of states around zero voltage and current via the application of an external magnetic field. This results into a drastic suppression of power dissipation which can be as low as a few ∼10−17 W. In this context, the interferometer allows an improvement of up to four orders of magnitude with respect to earlier SQUIPT designs and makes it ideal for extra-low power cryogenic applications. In addition, the N-SQUIPT has been recently predicted to be the enabling candidate for the implementation of coherent caloritronic devices based on proximity effect.
Validity of the concept of band edge in organic semiconductors
Authors: Horowitz Gilles
Published: September 2015

Because most organic semiconductors are disordered, the more appropriate function to describe their density of states (DOS) is the Gaussian distribution. A striking difference between the Gaussian DOS and the parabolic DOS found in conventional inorganic semiconductors is the fact that it does not allow for a simple and straightforward definition of the band edge. The most usual way found in the literature to define the band edge of a Gaussian DOS consists of extrapolating the tangent to the inflection point of the Gaussian curve. The aim of this paper is to discuss the validity of such a way of conduct. An analysis of data found in the literature shows that the width of the Gaussian distribution is significantly larger than what usually retained in transport models. It is also shown that the validity of the usual definition for the band edge is questioned by the fact that the density of charge carriers behave as a degenerate distribution, even at relatively low doping levels.
Magnetization dynamics of imprinted non-collinear spin textures
Authors: Streubel Robert , Fischer Peter , Kopte Martin , Schmidt Oliver G. , Makarov Denys
Published: September 2015

We study the magnetization dynamics of non-collinear spin textures realized via imprint of the magnetic vortex state in soft permalloy into magnetically hard out-of-plane magnetized Co/Pd nanopatterned heterostructures. Tuning the interlayer exchange coupling between soft- and hard-magnetic subsystems provides means to tailor the magnetic state in the Co/Pd stack from being vortex- to donut-like with different core sizes. While the imprinted vortex spin texture leads to the dynamics similar to the one observed for vortices in permalloy disks, the donut-like state causes the appearance of two gyrofrequencies characteristic of the early and later stages of the magnetization dynamics. The dynamics are described using the Thiele equation supported by the full scale micromagnetic simulations by taking into account an enlarged core size of the donut states compared to magnetic vortices.
Dissociative double-photoionization of butadiene in the 25-45 eV energy range using 3-D multi-coincidence ion momentum imaging spectrometry
Authors: Oghbaie Shabnam , Gisselbrecht Mathieu , Laksman Joakim , Månsson Erik P. , Sankari Anna , Sorensen Stacey L.
Published: September 2015

Dissociative double-photoionization of butadiene in the 25-45 eV energy range has been studied with tunable synchrotron radiation using full three-dimensional ion momentum imaging. Using ab initio calculations, the electronic states of the molecular dication below 33 eV are identified. The results of the measurement and calculation show that double ionization from π orbitals selectively triggers twisting about the terminal or central C–C bonds. We show that this conformational rearrangement depends upon the dication electronic state, which effectively acts as a gateway for the dissociation reaction pathway. For photon energies above 33 eV, three-body dissociation channels where neutral H-atom evaporation precedes C–C charge-separation in the dication species appear in the correlation map. The fragment angular distributions support a model where the dication species is initially aligned with the molecular backbone parallel to the polarization vector of the light, indicating a high probability for double-ionization to the “gateway states” for molecules with this orientation.
Temperature-dependent kinetic measurements and quasi-classical trajectory studies for the OH+ + H2/D2 → H2O+/HDO+ + H/D reactions
Authors: Martinez Oscar , Ard Shaun G. , Li Anyang , Shuman Nicholas S. , Guo Hua , Viggiano Albert A.
Published: September 2015

We have measured the temperature-dependent kinetics for the reactions of OH+ with H2 and D2 using a selected ion flow tube apparatus. Reaction occurs via atom abstraction to result in H2O+/HDO+ + H/D. Room temperature rate coefficients are in agreement with prior measurements and resulting temperature dependences are T0.11 for the hydrogen and T0.25 for the deuterated reactions. This work is prompted in part by recent theoretical work that mapped a full-dimensional global potential energy surface of H3O+ for the OH+ + H2 → H + H2O+ reaction [A. Li and H. Guo, J. Phys. Chem. A 118, 11168 (2014)], and reported results of quasi-classical trajectory calculations, which are extended to a wider temperature range and initial rotational state specification here. Our experimental results are in excellent agreement with these calculations which accurately predict the isotope effect in addition to an enhancement of the reaction rate constant due to the molecular rotation of OH+. The title reaction is of high importance to astrophysical models, and the temperature dependence of the rate coefficients determined here should now allow for better understanding of this reaction at temperatures more relevant to the interstellar medium.
High-mobility thin film transistors with neodymium-substituted indium oxide active layer
Authors: Lin Zhenguo , Lan Linfeng , Xiao Peng , Sun Sheng , Li Yuzhi , Song Wei , Gao Peixiong , Wang Lei , Ning Honglong , Peng Junbiao
Published: September 2015

Thin-film transistors (TFTs) with neodymium-substituted indium oxide (InNdO) channel layer were demonstrated. The structural properties of the InNdO films as a function of annealing temperature have been analyzed using X-ray diffraction and transmission electron microscopy. The InNdO thin films showed polycrystalline nature when annealed at 450 °C with a lattice parameter (cubic cell) of 10.255 Å, which is larger than the cubic In2O3 film (10.117 Å). The high-resolution transmission electron microscopy and energy dispersive X-ray spectroscopy showed that no Nd2O3 clusters were found in the InNdO film, implying that Nd was incorporated into the In2O3 lattice. The InNdO TFTs annealed at 450 °C exhibited more excellent electrical properties with a high mobility of 20.4 cm2 V−1 s−1 and better electric bias stability compared to those annealed at 300 °C, which was attributed to the reduction of the scattering centers and/or charge traps due to the decrease of the |Nd3d5/254f4O2p−1⟩ electron configuration.
Properties of K,Rb-intercalated C60 encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance
Authors: Mahfouz R. , Bouhrara M. , Kim Y. , Wågberg T. , Goze-Bac C. , Abou-Hamad E.
Published: September 2015

We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C60 encapsulated inside carbon nanotubes called peapods can be derived from 13C nuclear magnetic resonance investigations. Ring currents do play a basic role in those systems; in particular, the inner cavities of nanotubes offer an ideal environment to investigate the magnetism at the nanoscale. We report the largest diamagnetic shifts down to −68.3 ppm ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon intercalation. The metallization of intercalated peapods is evidenced from the chemical shift anisotropy and spin-lattice relaxation (T1) measurements. The observed relaxation curves signal a three-component model with two slow and one fast relaxing components. We assigned the fast component to the unpaired electrons charged C60 that show a phase transition near 100 K. The two slow components can be rationalized by the two types of charged C60 at two different positions with a linear regime following Korringa behavior, which is typical for metallic system and allow us to estimate the density of sate at Fermi level n(EF).
Contrast analysis of near-field scanning microscopy using a metal slit probe at millimeter wavelengths
Authors: Nozokido Tatsuo , Ishino Manabu , Seto Ryosuke , Bae Jongsuck
Published: September 2015

We describe an analytical method for investigating the signal contrast obtained in near-field scanning microscopy using a metal slit probe. The probe has a slit-like aperture at the open end of a rectangular or a parallel plate waveguide. In our method, the electromagnetic field around the metal slit aperture at the probe tip is calculated from Maxwell's equations in the Fourier domain in order to derive the electrical admittance of a sample system consisting of layered dielectrics as seen from the probe tip. A simple two-port electrical circuit terminated by this admittance is then established to calculate the complex reflection coefficient of the probe as a signal. The validity of the method is verified at millimeter wavelengths by a full-wave high frequency 3-D finite element modeler and also by experiment. The signal contrast when varying the short dimension of the slit aperture, the separation between the probe tip and the sample, and the sample thickness are successfully explained in terms of the variation in the product of the admittance and the characteristic impedance of the waveguide at the probe tip. In particular, the cause of the local minimum in the signal intensity when varying the separation is clarified.
Image analysis of speckle patterns as a probe of melting transitions in laser-heated diamond anvil cell experiments
Authors: Salem Ran , Matityahu Shlomi , Melchior Aviva , Nikolaevsky Mark , Noked Ori , Sterer Eran
Published: September 2015

The precision of melting curve measurements using laser-heated diamond anvil cell (LHDAC) is largely limited by the correct and reliable determination of the onset of melting. We present a novel image analysis of speckle interference patterns in the LHDAC as a way to define quantitative measures which enable an objective determination of the melting transition. Combined with our low-temperature customized IR pyrometer, designed for measurements down to 500 K, our setup allows studying the melting curve of materials with low melting temperatures, with relatively high precision. As an application, the melting curve of Te was measured up to 35 GPa. The results are found to be in good agreement with previous data obtained at pressures up to 10 GPa.
Polarization force-induced changes in the dust sheath formation
Authors: Mayout Saliha , Bentabet Karima , Tribeche Mouloud
Published: September 2015

The modifications arising in the dusty plasma sheath structure due to the presence of polarization forces acting on the dust grains are investigated. The corresponding appropriate Bohm criterion for sheath formation is obtained. It is found that the critical Mach number, beyond which the dusty plasma electrostatic sheath sets in, decreases whenever the polarization effects become important. In addition, when the polarization force dominates over the electrical one, the dust plasma sheath cannot set in. This happens whenever the dust grain size exceeds a critical threshold. Moreover, the sheath electrostatic potential-gradient becomes abruptly steep, and the sheath thickness becomes broader as the polarization force effects strengthen.
Design of blade-shaped-electrode linear ion traps with reduced anharmonic contributions
Authors: Deng K. , Che H. , Lan Y. , Ge Y. P. , Xu Z. T. , Yuan W. H. , Zhang J. , Lu Z. H.
Published: September 2015

RF quadrupole linear Paul traps are versatile tools in quantum physics experiments. Linear Paul traps with blade-shaped electrodes have the advantages of larger solid angles for fluorescence collection. But with these kinds of traps, the existence of higher-order anharmonic terms of the trap potentials can cause large heating rate for the trapped ions. In this paper, we theoretically investigate the dependence of higher-order terms of trap potentials on the geometry of blade-shaped traps, and offer an optimized design. A modified blade electrodes trap is proposed to further reduce higher-order anharmonic terms while still retaining large fluorescence collection angle.
Broadly continuously tunable slot waveguide quantum cascade lasers based on a continuum-to-continuum active region design
Authors: Meng Bo , Zeng Yong Quan , Liang Guozhen , Tao Jin , Hu Xiao Nan , Rodriguez Etienne , Wang Qi Jie
Published: September 2015

We report our progress in the development of broadly tunable single-mode slot waveguide quantum cascade lasers based on a continuum-to-continuum active region design. The electroluminescence spectrum of the continuum-to-continuum active region design has a full width at half maximum of 440 cm−1 at center wavelength ∼10 μm at room temperature (300 K). Devices using the optimized slot waveguide structure and the continuum-to-continuum design can be tuned continuously with a lasing emission over 42 cm−1, from 9.74 to 10.16 μm, at room temperature by using only current tuning scheme, together with a side mode suppression ratio of above 15 dB within the whole tuning range.
Theoretical study of hydrogen adsorption on Ca-decorated C48B12 clusters
Authors: Qi Pengtang , Chen Hongshan
Published: September 2015

The hydrogen adsorption on Ca-decorated C48B12 clusters is studied using density functional theory. The favorable binding site for Ca atom is the hexagonal C4B2 rings. The strong interaction between Ca atoms and C48B12 cluster hinders the aggregation of Ca atoms on the cluster surface. C48B12 is an electron deficient system with a large electron affinity of 2.952 eV. The decorated Ca atoms transfer their electrons to the cluster easily. The net charges on the Ca atoms are in the range of 1.101 to 1.563 e. When H2 molecules approach the Ca atoms, they are moderately polarized and adsorbed around the Ca atoms in molecular form. The adsorption strength can reach up to 0.133 eV/H2. Each Ca atom in the Ca-decorated C48B12 complexes can adsorb three H2 molecules. The fully decorated C48B12Ca6 can hold up to 18 H2 molecules.
Elastic and total cross sections for simple biomolecules in the intermediate energy range
Authors: Gupta Dhanoj , Naghma Rahla , Antony Bobby
Published: September 2015

The elastic and total cross sections for formaldehyde, acetaldehyde, acetone, 2-butanone and formamide are calculated using the spherical complex optical potential formalism in the intermediate energy range from 50 eV to 10 keV. These cross sections find application to various fields like radiation damage and biological sciences. The present results are compared with the available experimental and theoretical data and are found to give excellent agreement. The elastic cross sections reported for most of the targets in the present energy range are done for the first time. The energy dependence of the contribution of ionization and elastic cross section with respect to the total cross section and the correlation of total cross section with polarizability of the molecules are also studied.
Acousto-plasmofluidics: Acoustic modulation of surface plasmon resonance in microfluidic systems
Authors: Ahmed Daniel , Peng Xiaolei , Ozcelik Adem , Zheng Yuebing , Huang Tony Jun
Published: September 2015

We acoustically modulated the localized surface plasmon resonances (LSPRs) of metal nanostructures integrated within microfluidic systems. An acoustically driven micromixing device based on bubble microstreaming quickly and homogeneously mixes multiple laminar flows of different refractive indices. The altered refractive index of the mixed fluids enables rapid modulation of the LSPRs of gold nanodisk arrays embedded within the microfluidic channel. The device features fast response for dynamic operation, and the refractive index within the channel is tailorable. With these unique features, our “acousto-plasmofluidic” device can be useful in applications such as optical switches, modulators, filters, biosensors, and lab-on-a-chip systems.
Imaging robust microglial activation after lipopolysaccharide administration in humans with PET
Authors: Sandiego Christine M. , Gallezot Jean-Dominique , Pittman Brian , Nabulsi Nabeel , Lim Keunpoong , Lin Shu-Fei , Matuskey David , Lee Jae-Yun , O’Connor Kevin C. , Huang Yiyun , Carson Richard E. , Hannestad Jonas , Cosgrove Kelly P.
Published: September 2015

Significance

Neuroinflammation is a brain immune response that is associated with neurodegenerative diseases and is primarily driven by activation of microglia, the brain’s resident macrophages. Dysfunctional microglial activation may contribute to the behavioral changes observed in neurodegenerative diseases. Upon activation, microglia express translocator protein, which can be imaged with the radiotracer [
11
C]PBR28 and positron emission tomography (PET) in the living human brain. We imaged healthy human subjects with [
11
C]PBR28 and PET before and after i.v. administration of lipopolysaccharide (LPS), a potent immune activator. LPS produced a marked increase in brain microglial activation, peripheral inflammatory cytokine levels, and self-reported sickness symptoms. This imaging paradigm can provide a direct approach to test new medications for their potential to reduce acute neuroinflammation.
Bayesian logistic mixed-effects modelling of transect data: relating red tree coral presence to habitat characteristics
Authors: Masuda Michele M. , Stone Robert P.
Published: September 2015

The collection of continuous data on transects is a common practice in habitat and fishery stock assessments; however, the application of standard regression models that assume independence to serially correlated data is problematic. We show that generalized linear mixed models (GLMMs), i.e. generalized linear models for longitudinal data, that are normally used for studies performed over time can also be applied to other types of clustered or serially correlated data. We apply a specific GLMM for longitudinal data, a hierarchical Bayesian logistic mixed-effects model (BLMM), to a marine ecology dataset obtained from submersible video recordings of the seabed on transects at two sites in the Gulf of Alaska. The BLMM was effective in relating the presence of red tree corals (Primnoa pacifica; i.e. binary data) to habitat characteristics: the presence of red tree corals is highly associated with bedrock as the primary substrate (estimated odds ratio 9–19), high to very high seabed roughness (estimated odds ratio 3–5), and medium to high slope (estimated odds ratio 2–3). The covariate depth was less important at the sites. We also demonstrate and compare two methods of model checking: full and mixed posterior predictive assessments, the latter of which provided a more realistic assessment, and we calculate the variance partition coefficient for reporting the variation explained by multiple levels of the hierarchical model.
Methadone Pharmacogenetics
Authors: Kharasch Evan D. , Regina Karen J. , Blood Jane , Friedel Christina
Published: September 2015

AbstractAbstract

Compared with wild-type individuals, methadone metabolism and clearance were diminished in CYP2B6*6 carriers and increased in CYP2B6*4 carriers. Methadone metabolism and clearance were significantly lower in African Americans because of a larger proportion of CYP2B6*6 carriers and the absence of CYP2B6*4 carriers. These results may permit identification of individuals at risk for methadone overdose and may suggest genetically guided methadone dosing.

Background

Interindividual variability in methadone disposition remains unexplained, and methadone accidental overdose in pain therapy is a significant public health problem. Cytochrome P4502B6 (CYP2B6) is the principle determinant of clinical methadone elimination. The CYP2B6 gene is highly polymorphic, with several variant alleles. CYP2B6.6, the protein encoded by the CYP2B6*6 polymorphism, deficiently catalyzes methadone metabolism in vitro. This investigation determined the influence of CYP2B6*6, and other allelic variants encountered, on methadone concentrations, clearance, and metabolism.

Methods

Healthy volunteers in genotype cohorts CYP2B6*1/*1 (n = 21), CYP2B6*1/*6 (n = 20), and CYP2B6*6/*6 (n = 17), and also CYP2B6*1/*4 (n = 1), CYP2B6*4/*6 (n = 3), and CYP2B6*5/*5 (n = 2) subjects, received single doses of IV and oral methadone. Plasma and urine methadone and metabolite concentrations were determined by tandem mass spectrometry.

Results

Average S-methadone apparent oral clearance was 35 and 45% lower in CYP2B6*1/*6 and CYP2B6*6/*6 genotypes, respectively, compared with CYP2B6*1/*1. R-methadone apparent oral clearance was 25 and 35% lower in CYP2B6*1/*6 and CYP2B6*6/*6 genotypes, respectively, compared with CYP2B6*1/*1. R- and S-methadone apparent oral clearance was threefold and fourfold greater in CYP2B6*4 carriers. IV and oral R- and S-methadone metabolism was significantly lower in CYP2B6*6 carriers compared with that of CYP2B6*1 homozygotes and greater in CYP2B6*4 carriers. Methadone metabolism and clearance were lower in African Americans in part because of the CYP2B6*6 genetic polymorphism.

Conclusions

CYP2B6 polymorphisms influence methadone plasma concentrations, because of altered methadone metabolism and thus clearance. Genetic influence is greater for oral than IV methadone and S- than R-methadone. CYP2B6 pharmacogenetics explains, in part, interindividual variability in methadone elimination. CYP2B6 genetic effects on methadone metabolism and clearance may identify subjects at risk for methadone toxicity and drug interactions.
Capturing the Experience
Authors: Gripsrud Birgitta Haga , Brassil Kelly J. , Summers Barbara , Søiland Håvard , Kronowitz Steven , Lode Kirsten
Published: September 2015

Background:

Expressive writing has been shown to improve quality of life, fatigue, and posttraumatic stress among breast cancer patients across cultures. Understanding how and why the method may be beneficial to patients can increase awareness of the psychosocial impact of breast cancer and enhance interventional work within this population. Qualitative research on experiential aspects of interventions may inform the theoretical understanding and generate hypotheses for future studies.

Aim:

The aim of the study was to explore and describe the experience and feasibility of expressive writing among women with breast cancer following mastectomy and immediate or delayed reconstructive surgery.

Methods:

Seven participants enrolled to undertake 4 episodes of expressive writing at home, with semistructured interviews conducted afterward and analyzed using experiential thematic analysis.

Results:

Three themes emerged through analysis: writing as process, writing as therapeutic, and writing as a means to help others.

Conclusions:

Findings illuminate experiential variations in expressive writing and how storytelling encourages a release of cognitive and emotional strains, surrendering these to reside in the text. The method was said to process feelings and capture experiences tied to a new and overwhelming illness situation, as impressions became expressions through writing. Expressive writing, therefore, is a valuable tool for healthcare providers to introduce into the plan of care for patients with breast cancer and potentially other cancer patient groups.

Implications for Practice:

This study augments existing evidence to support the appropriateness of expressive writing as an intervention after a breast cancer diagnosis. Further studies should evaluate its feasibility at different time points in survivorship.
Back to School After Cancer Treatment
Authors: Choquette Anne , Rennick Janet E. , Lee Virginia
Published: September 2015

Background:

Little is known about the influence of cancer on the adolescent’s developing self-identity and social relationships as he/she transitions back to school following cancer treatment.

Objective:

The purpose of this study was to explore the meaning of returning to school for adolescents who have completed cancer treatment.

Methods:

In this qualitative study, in-depth interviews using an interpretive descriptive approach were conducted with 11 adolescents (aged 13–17 years) who had completed treatment for cancer. The transcripts of the audiotaped interviews were analyzed thematically and reviewed by the study team.

Results:

Three main themes suggested that the return to school hallmarked the end of an illness episode and a welcome return to a sense of well-being: (a) being on the right track, (b) bridging two worlds, and (c) establishing a new life at school. Nearly all adolescents described being negatively impacted by the cancer experience. However, the ability to maintain friendships during the transition emerged as particularly salient to allow the adolescents to rise above the challenges and residual effects of cancer treatment.

Conclusions:

Returning to school following cancer treatment affects adolescents’ beliefs about themselves, their self-identity, and their social relationships. Understanding the meaning that adolescents ascribed to returning to school facilitated the development of practice recommendations to improve adjustment to school.

Implications for Practice:

Our study findings illuminate an important gap in the existing resources for adolescents in the posttreatment phase of cancer. Recommendations to promote healthy psychosocial development are proposed to better support adolescents during the reintegration to school.
Pilot Randomized Controlled Trial of Auricular Point Acupressure to Manage Symptom Clusters of Pain, Fatigue, and Disturbed Sleep in Breast Cancer Patients
Authors: Yeh Chao Hsing , Chien Lung-Chang , Lin Wei-Chun , Bovbjerg Dana Howard , van Londen GJ
Published: September 2015

Background:

Current management for a symptom cluster of pain, fatigue, and disturbed sleep in breast cancer patients has limited effects.

Objective:

The purposes of this prospective, randomized controlled pilot study were to (1) assess the feasibility and tolerability of auricular point acupressure (APA) intervention to manage pain, fatigue, and sleep disturbance in breast cancer patients and (2) provide an initial appraisal of effect size as compared with a control intervention.

Methods:

Thirty-one participants were randomized into either an active APA group (n = 16) or a control APA group (n = 15), which included the sham APA treatment not related to the symptoms. All participants received the APA once a week for 4 weeks. Self-report measures were obtained at baseline, weekly during intervention, at end of intervention, and at a 1-month follow-up.

Results:

For the 4-week of APA treatment, the retention rate was 88% for the active APA group and 73% for the control APA group. After 4 weeks of APA, participants in the active APA treatment had reported a reduction of 71% in pain, 44% in fatigue, 31% in sleep disturbance, and 61% in interference with daily activities. The control APA group experienced some moderate reduction in these symptoms.

Conclusion:

Given that this was a pilot study with a small sample size, results must be interpreted with caution.

Implications for Practice:

Our results suggest that APA may provide an inexpensive and effective complementary approach for the management of symptom clusters for breast cancer patients, and further study is warranted.
WU-CRISPR: characteristics of functional guide RNAs for the CRISPR/Cas9 system
Authors: Wong Nathan , Liu Weijun , Wang Xiaowei
Published: September 2015

The CRISPR/Cas9 system has been rapidly adopted for genome editing. However, one major issue with this system is the lack of robust bioinformatics tools for design of single guide RNA (sgRNA), which determines the efficacy and specificity of genome editing. To address this pressing need, we analyze CRISPR RNA-seq data and identify many novel features that are characteristic of highly potent sgRNAs. These features are used to develop a bioinformatics tool for genome-wide design of sgRNAs with improved efficiency. These sgRNAs as well as the design tool are freely accessible via a web server, WU-CRISPR (http://crispr.wustl.edu).
ZNF191 Inhibits Hepatocellular Carcinoma Metastasis via DLG1-mediated YAP1 Inactivation
Authors: Wu Di , Li Haitao , Liu Yufeng , Saiyin Hexige , Wang Chenji , Wei Zhen , Zen Wenjiao , Liu Danyang , Chen Qi , Huang Haojie , Liu Guoyuan , Jiang Songmin , Yu Long
Published: September 2015

Searching targets for hepatocellular carcinoma (HCC) treatment, we identified zinc finger protein 191 (ZNF191) as a suppressor against HCC metastasis. Over-expressing ZNF191 in HCC cells impaired cell motility, while ZNF191 depletion promoted HCC cell migrationin vitroand metastasisin vivothrough triggering yes-associated protein 1 (YAP1) signaling. Chromatin immunoprecipitation-sequencing (ChIP-seq) revealed that ZNF191 specifically bound to the promoter ofDiscs, Large homolog 1(DLG1), a cell polarity maintainer and a negative regulator of YAP1. Double-knockdown experiments showed that DLG1 was not only the mediator of ZNF191’s function to suppress migration but also a link between ZNF191 and YAP1 signaling. ZNF191 was down-regulated in metastatic HCCs, correlating positively with DLG1 levels and inversely with YAP1 activation. Our findings indicate ZNF191 functions as a metastasis suppressor via DLG1-mediated YAP1 signaling inactivation.
The potential of electricity transmission corridors in forested areas as bumble bee habitat
Authors: Hill Bruce , Bartomeus Ignasi
Published: September 2015

Declines in pollinator abundance and diversity are not only a conservation issue but also a threat to crop pollination. Maintained infrastructure corridors, such as those containing electricity transmission lines, are potentially important wild pollinator habitat. However, there is a lack of evidence comparing the abundance and diversity of wild pollinators in transmission corridors with other important pollinator habitats. We compared the diversity of a key pollinator group, bumble bees (Bombus spp.), between transmission corridors and the surrounding semi-natural and managed habitat types at ten sites across Sweden’s Uppland region. Our results show that transmission corridors have no impact on bumble bee diversity in the surrounding area. However, transmission corridors and other maintained habitats have a level of bumble bees abundance and diversity comparable to semi-natural grasslands and host species that are important for conservation and ecosystem service provision. Under the current management regime, transmission corridors already provide valuable bumble bee habitat, but given that host plant density is the main determinant of bumble bee abundance, these areas could potentially be enhanced by establishing and maintaining key host plants. We show that in northern temperate regions the maintenance of transmission corridors has the potential to contribute to bumble bee conservation and the ecosystem services they provide.
Simultaneous enhancement of multiple stability properties using two-parameter control methods inDrosophila melanogaster
Authors: Tung Sudipta , Mishra Abhishek , Dey Sutirth
Published: September 2015

Abstract

Although a large number of methods have been proposed to control the non-linear dynamics of unstable popuations, very few have been actually adopted for application. One reason for this gap is the fact that few control methods have been empirically verified using biological populations. To address this issue, we investigated the effects of two well-studied control methods (Both Limiter Control and Target-Oriented Control) on the dynamics of unstable populations ofDrosophila melanogaster. We show that both methods can significantly reduce population fluctuations, decrease extinction probability and increase effective population size simultaneously. This is in contrast with single parameter control methods that are not able to achieve multiple aspects of stability at the same time. We use the distribution of population sizes to derive biologically intuitive explanations for the mechanisms of how these two control methods attain stability. Finally, we show that non-Drosophila specific biologically realistic simulations are able to capture almost all the trends of our data. This shows that our results are likely generalizable over a wide range of taxa. The primary insight of our study is that control methods that incorporate both culling and restocking have better all-round performance in terms of stabilizing populations.
MTG2: An efficient algorithm for multivariate linear mixed model analysis based on genomic information
Authors: Lee S.H. , van der Werf J.H.J.
Published: September 2015

We have developed an algorithm for genetic analysis of complex traits using genome-wide SNPs in a linear mixed model framework. Compared to current standard REML software based on the mixed model equation, our method could be more than 1000 times faster. The advantage is largest when there is only a single genetic covariance structure. The method is particularly useful for multivariate analysis, including multitrait models and random regression models for studying reaction norms. We applied our proposed method to publicly available mice and human data and discuss advantages and limitations.

Availability:MTG2 is available inhttps://sites.google.com/site/honglee0707/mtg2.

Contact:hong.lee@une.edu.au

Supplementary information:Supplementary data are available.
Laplacian eigenmaps and principal curves for high resolution pseudotemporal ordering of single-cell RNA-seq profiles
Authors: Campbell Kieran , Ponting Chris P , Webber Caleb
Published: September 2015

Advances in RNA-seq technologies provide unprecedented insight into the variability and heterogeneity of gene expression at the single-cell level. However, such data offers only a snapshot of the transcriptome, whereas it is often the progression of cells through dynamic biological processes that is of interest. As a result, one outstanding challenge is to infer such progressions by ordering gene expression from single cell data alone, known as the cell ordering problem. Here, we introduce a new method that constructs a low-dimensional non-linear embedding of the data using laplacian eigenmaps before assigning each cell a pseudotime using principal curves. We characterise why on a theoretical level our method is more robust to the high levels of noise typical of single-cell RNA-seq data before demonstrating its utility on two existing datasets of differentiating cells.