bluuebunny/crossref_metadata_2025 huggingface dataset:
Wetting and dewetting of narrow hydrophobic channels by orthogonal electric fields: Structure, free energy, and dynamics for different water models
Authors: Kayal Abhijit , Chandra Amalendu
Published: December 2015

Wetting and dewetting of a (6,6) carbon nanotube in presence of an orthogonal electric field of varying strengths are studied by means of molecular dynamics simulations using seven different models of water. We have looked at filling of the channel, occupancy and structure of water inside it, associated free energy profiles, and also dynamical properties like the time scales of collective dipole flipping and residence dynamics. For the current systems where the entire simulation box is under the electric field, the nanotube is found to undergo electrodrying, i.e., transition from filled to empty states on increase of the electric field. The free energy calculations show that the empty state is the most stable one at higher electric field as it raptures the hydrogen bond environment inside the carbon nanotube by reorienting water molecules to its direction leading to a depletion of water molecules inside the channel. We investigated the collective flipping of water dipoles inside the channel and found that it follows a fast stepwise mechanism. On the dynamical side, the dipole flipping is found to occur at a faster rate with increase of the electric field. Also, the rate of water flow is found to decrease dramatically as the field strength is increased. The residence time of water molecules inside the channel is also found to decrease with increasing electric field. Although the effects of electric field on different water models are found to be qualitatively similar, the quantitative details can be different for different models. In particular, the dynamics of water molecules inside the channel can vary significantly for different water models. However, the general behavior of wetting and dewetting transitions, enhanced dipole flips, and shorter residence times on application of an orthogonal electric field hold true for all water models considered in the current work.
Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications
Authors: Morawski Ireneusz , Spiegelberg Richard , Korte Stefan , Voigtländer Bert
Published: December 2015

A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. The high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations.
Hysteresis free carbon nanotube thin film transistors comprising hydrophobic dielectrics
Authors: Lefebvre J. , Ding J. , Li Z. , Cheng F. , Du N. , Malenfant P. R. L.
Published: December 2015

We present two examples of carbon nanotube network thin film transistors with strongly hydrophobic dielectrics comprising either Teflon-AF or a poly(vinylphenol)/poly(methyl silsesquioxane) (PVP/pMSSQ) blend. In the absence of encapsulation, bottom gated transistors in air ambient show no hysteresis between forward and reverse gate sweep direction. Device threshold gate voltage and On-current present excellent time dependent stability even under dielectric stress. Furthermore, threshold gate voltage for hole conduction is negative upon device encapsulation with PVP/pMSSQ enabling much improved current On/Off ratio at 0 V. This work addresses two major challenges impeding solution based fabrication of relevant thin film transistors with printable single-walled carbon nanotube channels.
Time-resolved laser-induced fluorescence measurement of ion and neutral dynamics in a Hall thruster during ionization oscillations
Authors: Lucca Fabris Andrea , Young Christopher V. , Cappelli Mark A.
Published: December 2015

The paper presents spatially and temporally resolved laser-induced fluorescence (LIF) measurements of the xenon ion and neutral velocity distribution functions in a 400 W Hall thruster during natural ionization oscillations at 23 kHz, the so-called “breathing mode.” Strong fluctuations in measured axial ion velocity throughout the discharge current cycle are observed at five spatial locations and the velocity maxima appear in the low current interval. The spatio-temporal evolution of the ion velocity distribution function suggests a propagating acceleration front undergoing periodic motion between the thruster exit plane and ∼1 cm downstream into the plume. The ion LIF signal intensity oscillates almost in phase with the discharge current, while the neutral fluorescence signal appears out of phase, indicating alternating intervals of strong and weak ionization.
Structural and optical properties of axial silicon-germanium nanowire heterojunctions
Authors: Wang X. , Tsybeskov L. , Kamins T. I. , Wu X. , Lockwood D. J.
Published: December 2015

Detailed studies of the structural and optical properties of axial silicon-germanium nanowire heterojunctions show that despite the 4.2% lattice mismatch between Si and Ge they can be grown without a significant density of structural defects. The lattice mismatch induced strain is partially relieved due to spontaneous SiGe intermixing at the heterointerface during growth and lateral expansion of the Ge segment of the nanowire. The mismatch in Ge and Si coefficients of thermal expansion and low thermal conductivity of Si/Ge nanowire heterojunctions are proposed to be responsible for the thermally induced stress detected under intense laser radiation in photoluminescence and Raman scattering measurements.
Bottom-up coarse-grained models that accurately describe the structure, pressure, and compressibility of molecular liquids
Authors: Dunn Nicholas J. H. , Noid W. G.
Published: December 2015

The present work investigates the capability of bottom-up coarse-graining (CG) methods for accurately modeling both structural and thermodynamic properties of all-atom (AA) models for molecular liquids. In particular, we consider 1, 2, and 3-site CG models for heptane, as well as 1 and 3-site CG models for toluene. For each model, we employ the multiscale coarse-graining method to determine interaction potentials that optimally approximate the configuration dependence of the many-body potential of mean force (PMF). We employ a previously developed “pressure-matching” variational principle to determine a volume-dependent contribution to the potential, UV(V), that approximates the volume-dependence of the PMF. We demonstrate that the resulting CG models describe AA density fluctuations with qualitative, but not quantitative, accuracy. Accordingly, we develop a self-consistent approach for further optimizing UV, such that the CG models accurately reproduce the equilibrium density, compressibility, and average pressure of the AA models, although the CG models still significantly underestimate the atomic pressure fluctuations. Additionally, by comparing this array of models that accurately describe the structure and thermodynamic pressure of heptane and toluene at a range of different resolutions, we investigate the impact of bottom-up coarse-graining upon thermodynamic properties. In particular, we demonstrate that UV accounts for the reduced cohesion in the CG models. Finally, we observe that bottom-up coarse-graining introduces subtle correlations between the resolution, the cohesive energy density, and the “simplicity” of the model.
The consequences of improperly describing oscillator strengths beyond the electric dipole approximation
Authors: Lestrange Patrick J. , Egidi Franco , Li Xiaosong
Published: December 2015

The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strength can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities.
Wakefields generated by collisional neutrinos in neutral-electron-positron-ion plasma
Authors: Tinakiche Nouara
Published: December 2015

A classical fluid description is adopted to investigate nonlinear interaction between an electron-type neutrino beam and a relativistic collisionless unmagnetized neutral-electron-positron-ion plasma. In this work, we consider the collisions of the neutrinos with neutrals in the plasma and study their effect on the generation of wakefields in presence of a fraction of ions in a neutral-electron-positron plasma. The results obtained in the present work are interpreted and compared with previous studies.
Effects of the local structure dependence of evaporation fields on field evaporation behavior
Authors: Yao Lan , Withrow Travis , Restrepo Oscar D. , Windl Wolfgang , Marquis Emmanuelle A.
Published: December 2015

Accurate three dimensional reconstructions of atomic positions and full quantification of the information contained in atom probe microscopy data rely on understanding the physical processes taking place during field evaporation of atoms from needle-shaped specimens. However, the modeling framework for atom probe microscopy has only limited quantitative justification. Building on the continuum field models previously developed, we introduce a more physical approach with the selection of evaporation events based on density functional theory calculations. This model reproduces key features observed experimentally in terms of sequence of evaporation, evaporation maps, and depth resolution, and provides insights into the physical limit for spatial resolution.
Nanocomposite bismuth zinc niobate tantalate for flexible energy storage applications
Authors: Michael-Sapia Elizabeth K. , Li Haoyu U. , Jackson Thomas N. , Trolier-McKinstry Susan
Published: December 2015

The development of complex oxides that can be processed at temperatures at and below 350 °C is desirable for their integration onto polymeric substrates, enabling their use in flexible applications. Nanocomposite films consisting of a nanocrystalline fluorite related to delta-bismuth oxide in an amorphous matrix were prepared via chemical solution deposition. These solutions were batched with the composition Bi1.5Zn0.9Nb1.35Ta0.15O6.9. The nanocomposite had a relative permittivity of 50 ± 2 and dielectric losses on the order of 0.03 ± 0.01. For measurement frequencies of 1 kHz and 10 kHz, the nanocomposite demonstrated a breakdown strength of 3.8 MV/cm, and a room-temperature energy storage density of approximately 40.2 ± 1.7 J/cm3. To determine the suitability of the nanocomposite films for use in flexible applications, flexible nanocomposite films underwent repetitive compressive and tensile bending around a minimum bend diameter of 7 mm, which corresponded to a strain of 0.10%. After bending the films 30 000 times, the energy storage density of the films was unchanged, demonstrating that nanocomposite bismuth zinc niobate tantalate films are suitable for flexible energy storage applications.
Role of bubble growth dynamics on microscale heat transfer events in microchannel flow boiling process
Authors: Bigham Sajjad , Moghaddam Saeed
Published: December 2015

For nearly two decades, the microchannel flow boiling heat transfer process has been the subject of numerous studies. A plethora of experimental studies have been conducted to decipher the underlying physics of the process, and different hypotheses have been presented to describe its microscopic details. Despite these efforts, the underlying assumptions of the existing hypothesis have remained largely unexamined. Here, using data at the microscopic level provided by a unique measurement approach, we deconstruct the boiling heat transfer process into a set of basic mechanisms and explain their role in the overall surface heat transfer. We then show how this knowledge allows to relate the bubble growth and flow dynamics to the surface heat flux.
Study on the oxygen vacancy redistribution and the mechanism of electrical manipulation of ferromagnetism in diluted magnetic oxides
Authors: Ren Shuxia , Dong Jingyu , Chen Wei , Zhang Liyong , Guo Jiajun , Zhang Li , Zhao Jing , Zhao Xu
Published: December 2015

Electrical manipulation of room temperature ferromagnetism (RTFM) has been observed in several kinds of transition metal doped diluted magnetic oxide films. We demonstrate using X-ray photoelectron spectroscopy that the redistribution of the oxygen vacancies in a film under an electric field plays a crucial role in the enhancement of the RTFM. Based on a detailed analysis of the X-ray photoelectron spectroscopy data for the oxygen vacancy distribution in different resistive states, a unified mechanism has been proposed. This work points out a new direction for improving the magnetic properties of these materials by controlling oxygen vacancies in the interior of the films.
Mixed Al and Si doping in ferroelectric HfO2 thin films
Authors: Lomenzo Patrick D. , Takmeel Qanit , Zhou Chuanzhen , Chung Ching-Chang , Moghaddam Saeed , Jones Jacob L. , Nishida Toshikazu
Published: December 2015

Ferroelectric HfO2 thin films 10 nm thick are simultaneously doped with Al and Si. The arrangement of the Al and Si dopant layers within the HfO2 greatly influences the resulting ferroelectric properties of the polycrystalline thin films. Optimizing the order of the Si and Al dopant layers led to a remanent polarization of ∼20 μC/cm2 and a coercive field strength of ∼1.2 MV/cm. Post-metallization anneal temperatures from 700 °C to 900 °C were used to crystallize the Al and Si doped HfO2 thin films. Grazing incidence x-ray diffraction detected differences in peak broadening between the mixed Al and Si doped HfO2 thin films, indicating that strain may influence the formation of the ferroelectric phase with variations in the dopant layering. Endurance characteristics show that the mixed Al and Si doped HfO2 thin films exhibit a remanent polarization greater than 15 μC/cm2 up to 108 cycles.
The scattering matrix approach: A study of elastic waves propagation in one-dimensional disordered phononic crystals
Authors: Pernas-Salomón R. , Pérez-Álvarez R. , Lazcano Z. , Arriaga J.
Published: December 2015

A straightforward scattering matrix method derived from the Hybrid matrix method is proposed to study band gaps of elastic waves propagating along an arbitrary direction in one-dimensional ordered and disordered phononic crystals. We show that this is a suitable alternative methodology to overcome the numerical degradation manifested by the standard transfer matrix method even in calculations where nonlossy elastic medium and/or relatively low angles of incidence are involved. Using the wave equation in the matrix Sturm-Liouville form, we show analytically that we can use the value of the determinant of the associated transfer matrix T, to check the numerical accuracy of our calculations. The localization factor concept and transmittance spectra are used to describe the band gaps. In contrast to the matrix T, the numerical stability of the proposed scattering matrix allows to obtain true transmittance spectra whose band gaps correspond to those predicted by the localization factor values for both ordered and disordered phononic crystals. Furthermore, for the numerical examples provided, the proposed method requires fewer iterations to obtain the same value of the Lyapunov exponent compared with the standard transfer matrix method.
E × B probe measurements in molecular and electronegative plasmas
Authors: Renaud D. , Gerst D. , Mazouffre S. , Aanesland A.
Published: December 2015

This paper reports on the design, the building, the calibration, and the use of a compact E × B probe that acts as a velocity filter or a mass filter for ion species. A series of measurements has been performed in the discharge and in the beam of the PEGASES (Plasma Propulsion with Electronegative GASES) ion source. PEGASES is a unique inductively coupled radio-frequency source able to generate a beam of positive and negative ions when operated with an electronegative gas. In this study, experiments have been carried out with SF6. Calibrated E × B probe spectra indicate that the diagnostic tool can be used to determine the ion velocity and the plasma composition even when many molecular fragments are present. In addition, the probe is able to detect both positive and negative ions. Measurements show a large variety of positively charged ions coming from SF6. Conversely, the beam is solely composed of F− and SF6− negative ions in compliance with computer simulations.
Changes in terrestrial organic matter and pollutant input to the Yangtze River Estuary, East China Sea, during the past century
Authors: Duan Xiaoyong , Li Yanxia , Li Xianguo , Gao Yi , Zhang Dahai
Published: December 2015

Environmental contextThe concentrations of n-alkanes, phthalates and alkylphenols in a dated sediment core from the Yangtze River estuary steadily increased, with evident peaks in c. 1980 and c. 2000. Most of the phthalates and alkylphenols in the core originated from direct industrial and municipal discharges into the lower reaches of the Yangtze River, whereas the n-alkanes were mainly from aquatic and terrestrial plants. The Yangtze River discharge plays an important role in the sedimentary records of organic compounds.
AbstractThe depositional records of phthalate esters (PAEs), alkylphenols (APs) and n-alkanes in the Yangtze River Estuary over the past century were constructed using a dated sediment core to help reconstruct the environmental history. The n-alkane concentrations increased steadily. All the samples had a resolved lower-alkane pattern with well-defined even-over-odd predominance. The n-alkanes originated largely from aquatic and terrestrial plants (83.6%), the remainder being contributed by way of biotransformation in the land soil and river (16.4%). The down-core concentration profiles of PAEs and APs increased rapidly, with evident peaks in the 1980s and c. 2000. PAE and AP homologues were dominated by dibutyl phthalate and nonylphenol respectively, originating mainly from industrial and municipal discharges (79.5%). Long-range transportation from the upper and middle reaches played a much smaller role (20.5%), especially in recent decades. The changes in the Yangtze River discharge and the modification of the water system played important roles in the transport of organic compounds, especially after the 1950s.
Comparison of soils and plants on the active and relic parts of a recolonised burrowing bettong (Bettongia lesueur) warren
Authors: Chapman Tamra F.
Published: December 2015

The burrowing bettong (Bettongia lesueur) is a rat-kangaroo that digs while foraging and is the only marsupial to construct warrens and live communally in them. It previously occurred over a large part of Australia, but was extinct on the mainland by the early 1960s, before its role in ecosystem function could be understood. Bettongs, sourced from island and captive populations, were reintroduced as part of a rangeland restoration program at Matuwa (Lorna Glen) in central Western Australia. This study compared soil properties and plant productivity on the active and relic parts of a single warren to determine whether the presence of the bettongs was likely to be of benefit at the patch scale. Soil rock content, hydraulic conductivity, mineral nitrogen, phosphorus, potassium and sulfur were significantly higher for soils on the active part than on the relic part of the warren. Cotton bush (Ptilotus obovatus) shrubs were similar in size for the areas compared, but those growing on the active part of the warren had significantly more living tissue, greater leaf biomass and larger leaves, with higher moisture and nutrient content. These responses are indicative of access to additional mineral nutrients, probably derived from the urine and faeces of the bettongs. Only one warren was investigated in the present study and thus, this was a ‘patch’ level, unreplicated study. A broader, landscape-scale study is recommended, to compare relic warrens and active warrens with undisturbed sites, to confirm the hypotheses raised as a result of this study.
Round-the-clock power supply and a sustainable economy via synergistic integration of solar thermal power and hydrogen processes
Authors: Gençer Emre , Mallapragada Dharik S. , Maréchal François , Tawarmalani Mohit , Agrawal Rakesh
Published: December 2015

Significance

Diminishing fossil fuel resources and increasing atmospheric greenhouse gases present a compelling case for transitioning to a sustainable economy where all human needs can be met by using abundant solar energy. In this paper, we introduce “hydricity,” a paradigm that proposes synergistic coproduction of solar thermal power and hydrogen. We realize hydricity by judiciously integrating solar water power cycle, solar thermal hydrogen production techniques, and turbine-based hydrogen power cycle and by suitably improving each one for compatibility and beneficial interaction. The proposed hydricity concept presents a potential breakthrough solution for continuous and efficient power supply and also an exciting opportunity to envision and create a sustainable economy to meet all the human needs—namely, food, chemicals, transportation, heating, and electricity.
The point of no return in vetoing self-initiated movements
Authors: Schultze-Kraft Matthias , Birman Daniel , Rusconi Marco , Allefeld Carsten , Görgen Kai , Dähne Sven , Blankertz Benjamin , Haynes John-Dylan
Published: December 2015

Significance

Many studies have shown that movements are preceded by early brain signals. There has been a debate as to whether subjects can still cancel a movement after onset of these early signals. We tested whether subjects can win a “duel” against a brain–computer interface designed to predict their movements in real time from observations of their EEG activity. Our findings suggest that subjects can exert a “veto” even after onset of this preparatory process. However, the veto has to occur before a point of no return is reached after which participants cannot avoid moving.
Musclin is an activity-stimulated myokine that enhances physical endurance
Authors: Subbotina Ekaterina , Sierra Ana , Zhu Zhiyong , Gao Zhan , Koganti Siva Rama Krishna , Reyes Santiago , Stepniak Elizabeth , Walsh Susan A. , Acevedo Michael R. , Perez-Terzic Carmen M. , Hodgson-Zingman Denice M. , Zingman Leonid V.
Published: December 2015

Significance

Skeletal muscle is increasingly recognized as a secretory organ. Revealing the identity and function of myokines can improve our understanding of skeletal muscle function under sedentary or exercise conditions, as well as its coordination with other organs, tissues, and overall body metabolism. This study identifies musclin as an exercise-responsive myokine critical for skeletal muscle adaptation to physical activity. We develop a musclin-encoding gene (
Ostn
) knockout mouse, which allows us to determine a previously unrecognized physiologic function of musclin in regulation of skeletal muscle mitochondrial biogenesis and physical endurance. The demonstrated molecular mechanism for musclin-dependent skeletal muscle adaptation to exercise also transforms the perspective on natriuretic peptide signaling, particularly as it relates to physical activity and exercise-induced remodeling in different tissues.
Neural mechanisms of social decision-making in the primate amygdala
Authors: Chang Steve W. C. , Fagan Nicholas A. , Toda Koji , Utevsky Amanda V. , Pearson John M. , Platt Michael L.
Published: December 2015

Significance

Making social decisions requires evaluation of benefits and costs to self and others. Long associated with emotion and vigilance, neurons in primate amygdala also signal reward and punishment as well as information about the faces and eyes of others. Here we show that neurons in the basolateral amygdala signal the value of rewards for self and others when monkeys make social decisions. These value-mirroring neurons reflected monkeys’ tendency to make prosocial decisions on a momentary as well as long-term basis. We also found that delivering the social peptide oxytocin into basolateral amygdala enhances both prosocial tendencies and attention to the recipients of prosocial decisions. Our findings endorse the amygdala as a critical neural nexus regulating social decisions.
Exogenous Hsp70 delays senescence and improves cognitive function in aging mice
Authors: Bobkova Natalia V. , Evgen’ev Mikhail , Garbuz David G. , Kulikov Alexei M. , Morozov Alexei , Samokhin Alexander , Velmeshev Dmitri , Medvinskaya Natalia , Nesterova Inna , Pollock Andrew , Nudler Evgeny
Published: December 2015

Significance

The compromised ability of neurons to express Heat Shock Protein 70 (Hsp70) correlates with aging-related neurodegeneration. In this study, middle-aged and old mice were treated chronically until death with human Hsp70 delivered intranasally and were investigated after 5 or 9 mo of Hsp70 treatment for their cognitive ability and synaptic density. Hsp70 treatment extended mean and maximum lifespan, improved learning and memory in old animals, increased curiosity, decreased anxiety, and helped maintain synaptic structures that degrade with age. These results provide evidence that intranasal administration of Hsp70 could have significant therapeutic potential in preserving brain tissue and memory for middle-age and old individuals and could be applied either as unique self-contained treatment or in combination with other pharmacological therapies.
KCNE3 acts by promoting voltage sensor activation in KCNQ1
Authors: Barro-Soria Rene , Perez Marta E. , Larsson H. Peter
Published: December 2015

Significance

The association of KCNE3 beta subunits to KCNQ1 channels turns voltage-dependent KCNQ1 channels into apparent voltage-independent KCNQ1/KCNE3 channels that are important for the transport of water and salts across epithelial cell layers. Because KCNQ1/KCNE3 channels are necessary for water and salt secretion in the colon, KCNQ1/KCNE3 channels are a potential drug target in the treatment of secretory diarrhea. Mutations in KCNE3 have also been associated with diseases such as cardiac arrhythmia and tinnitus. We here propose a model for how KCNE3 turns KCNQ1 into a voltage-independent channel. Our model will allow for a better understanding of how mutations in KCNQ1 and KCNE3 cause diseases and how to design drugs to treat these diseases.
BovineNK-lysin: Copy number variation and functional diversification
Authors: Chen Junfeng , Huddleston John , Buckley Reuben M. , Malig Maika , Lawhon Sara D. , Skow Loren C. , Lee Mi Ok , Eichler Evan E. , Andersson Leif , Womack James E.
Published: December 2015

Significance

The cattle genome contains expanded families of several genes involved in innate immunity. A single copy of theNK-lysingene is annotated in the genomes of most mammals, including humans, but this study identified a family ofNK-lysingenes in cattle consisting of four functional members. Although this family mirrors the numerical expansion of other immune-related genes, including interferons, defensins, and cathelicidins, in the cattle genome, we also see a diversification of function exhibited by differential tissue expression in the gene family. The current state of this site in the bovine genome appears to capture the evolutionary transition from copy number variation to the fixation of novel gene function within a segmentally duplicated region.
Unveiling the crucial intermediates in androgen production
Authors: Mak Piotr J. , Gregory Michael C. , Denisov Ilia G. , Sligar Stephen G. , Kincaid James R.
Published: December 2015

Significance

The human enzyme cytochrome P450 17A1 (CYP17A1) catalyzes the critical step in the biosynthesis of the male sex hormones, and, as such, it is a key target for the inhibition of testosterone production that is necessary for the progression of certain cancers. CYP17A1 catalyzes two distinct types of chemical transformations. The first is the hydroxylation of the steroid precursors pregnenolone and progesterone. The second is a different reaction involving carbon–carbon (C-C) bond cleavage, the mechanism of which has been actively debated in the literature. Using a combination of chemical and biophysical methods, we have been able to trap and characterize the active intermediate in this C-C lyase reaction, an important step in the potential design of mechanism-based inhibitors for the treatment of prostate cancers.
H1N1 influenza virus induces narcolepsy-like sleep disruption and targets sleep–wake regulatory neurons in mice
Authors: Tesoriero Chiara , Codita Alina , Zhang Ming-Dong , Cherninsky Andrij , Karlsson Håkan , Grassi-Zucconi Gigliola , Bertini Giuseppe , Harkany Tibor , Ljungberg Karl , Liljeström Peter , Hökfelt Tomas G. M. , Bentivoglio Marina , Kristensson Krister
Published: December 2015

Significance

Influenza A virus infections are risk factors for narcolepsy, a disease in which autoimmunity has been implicated. We tested experimentally whether influenza virus infections could be causally related to narcolepsy. We found that mice infected with a H1N1 influenza A virus strain developed over time sleep–wake changes described in murine models of narcolepsy and narcolepsy patients. In the brain, the virus infected orexin/hypocretin-producing neurons, which are destroyed in human narcolepsy, and other cells in the distributed sleep–wake-regulating neuronal network. The findings, obtained in mice lacking an adaptive autoimmune response, thus provide new avenues for research on infection-related mechanisms in narcolepsy.
Methylome analysis reveals an important role for epigenetic changes in the regulation of the
Arabidopsis
response to phosphate starvation
Authors: Yong-Villalobos Lenin , González-Morales Sandra Isabel , Wrobel Kazimierz , Gutiérrez-Alanis Dolores , Cervantes-Peréz Sergio Alan , Hayano-Kanashiro Corina , Oropeza-Aburto Araceli , Cruz-Ramírez Alfredo , Martínez Octavio , Herrera-Estrella Luis
Published: December 2015

Significance

Significant progress has been achieved in our understanding of plant adaptive responses to ensure growth and reproduction in soils with low phosphate (Pi) availability. However, the potential role of epigenetic mechanisms in the modulation of these responses remains largely unknown. In this article, we describe dynamic changes in global DNA methylation patterns that occur in
Arabidopsis
plants exposed to low Pi availability; these changes are associated with the onset of Pi starvation responses. We show that the expression of a subset of low Pi-responsive genes is modulated by methylation changes and that DNA methylation is required for the proper establishment of developmental and molecular responses to Pi starvation.
Rapid and profound rewiring of brain lipid signaling networks by acute diacylglycerol lipase inhibition
Authors: Ogasawara Daisuke , Deng Hui , Viader Andreu , Baggelaar Marc P. , Breman Arjen , den Dulk Hans , van den Nieuwendijk Adrianus M. C. H. , Soethoudt Marjolein , van der Wel Tom , Zhou Juan , Overkleeft Herman S. , Sanchez-Alavez Manuel , Mori Simone , Nguyen William , Conti Bruno , Liu Xiaojie , Chen Yao , Liu Qing-song , Cravatt Benjamin F. , van der Stelt Mario
Published: December 2015

Significance

Lipid transmitters, such as endocannabinoid and eicosanoids, play important roles in the nervous system and regulate behaviors that include pain, emotionality, and addiction. Chemical probes that perturb lipid transmitter biosynthesis are needed to understand the functions of these pathways in the nervous system. Here, we describe selective and in vivo active inhibitors of the diacylglycerol lipases DAGLα and DAGLβ, which biosynthesize the endocannabinoid 2-arachidonoylglycerol (2-AG). We show that these inhibitors produce rapid and dramatic changes in a brain lipid signaling network, comprising not only 2-AG, but also eicosanoids and diacylglycerols. These lipid changes are accompanied by impairments in synaptic plasticity and attenuation of neuroinflammatory responses in vivo, underscoring the broad role that DAGLs play in nervous system metabolism and function.
Polymer-supported CuPd nanoalloy as a synergistic catalyst for electrocatalytic reduction of carbon dioxide to methane
Authors: Zhang Sheng , Kang Peng , Bakir Mohammed , Lapides Alexander M. , Dares Christopher J. , Meyer Thomas J.
Published: December 2015

Significance

Photo- and electrochemical CO
2
reduction to carbon fuels is not only an attractive solution to the greenhouse effect, but could also become an integral part of a global energy storage strategy with renewable electrical energy sources used to store energy in the chemical bonds of carbon fuels. A novel electrodeposition strategy is reported here for the preparation of highly dispersed, ultrafine metal nanoparticles and nanoalloys on an electroactive polymeric film. It is shown that a bimetallic Cu–Pd nanoalloy exhibits a greater than twofold enhancement in Faradaic efficiency for CO
2
reduction to methane compared with a state-of-the-art nanoCu catalyst. The fabrication procedure for the alloy nanoparticles is straightforward and applicable as a general procedure for catalytic electrodes for integrated electrolysis devices.
Contact efflorescence as a pathway for crystallization of atmospherically relevant particles
Authors: Davis Ryan D. , Lance Sara , Gordon Joshua A. , Ushijima Shuichi B. , Tolbert Margaret A.
Published: December 2015

Significance

Atmospheric particles contain inorganic material that can effloresce to form a crystalline solid. The phase state of atmospheric particles influences the particle’s effect on climate and air quality. Despite the importance of particle phase, there is no comprehensive understanding of particle crystallization, and many climate models assume inorganic particles always remain liquid. Our study demonstrates that contact efflorescence, a previously unexplored pathway for crystallization, can lead to the formation of solid particulate at high relative humidity (RH, ∼80%) upon a single collision. Particles then remain crystalline at all relative humidities below their deliquescence point (<80% RH). Such a high efflorescence RH strongly suggests contact efflorescence may be an important atmospheric process to consider further.
Opening nodes on horosphere packings
Authors: Traizet Martin
Published: December 2015

We use Bryant representation to construct constant mean curvature-1 surfaces in hyperbolic space by desingularisation of a horosphere packing.
destiny: diffusion maps for large-scale single-cell data in R
Authors: Angerer Philipp , Haghverdi Laleh , Büttner Maren , Theis Fabian J. , Marr Carsten , Buettner Florian
Published: December 2015

Summary: Diffusion maps are a spectral method for non-linear dimension reduction and have recently been adapted for the visualization of single-cell expression data. Here we present destiny, an efficient R implementation of the diffusion map algorithm. Our package includes a single-cell specific noise model allowing for missing and censored values. In contrast to previous implementations, we further present an efficient nearest-neighbour approximation that allows for the processing of hundreds of thousands of cells and a functionality for projecting new data on existing diffusion maps. We exemplarily apply destiny to a recent time-resolved mass cytometry dataset of cellular reprogramming.

Availability and implementation: destiny is an open-source R/Bioconductor package “bioconductor.org/packages/destiny” also available at www.helmholtz-muenchen.de/icb/destiny. A detailed vignette describing functions and workflows is provided with the package.

Contact:  carsten.marr@helmholtz-muenchen.de or f.buettner@helmholtz-muenchen.de

Supplementary information:  Supplementary data are available at Bioinformatics online.
Fisheries, the inverted food pyramid
Authors: Kolding Jeppe , Bundy Alida , van Zwieten Paul A.M. , Plank Michael J.
Published: December 2015

A global assessment of fishing patterns and fishing pressure from 110 different Ecopath models, representing marine ecosystems throughout the world and covering the period 1970–2007, show that human exploitation across trophic levels (TLs) is highly unbalanced and skewed towards low productive species at high TLs, which are around two TLs higher than the animal protein we get from terrestrial farming. Overall, exploitation levels from low trophic species were <15% of production, and only 18% of the total number of exploited groups and species were harvested >40% of their production. Generally, well-managed fisheries from temperate ecosystems were more selectively harvested at higher exploitation rates than tropical and upwelling (tropical and temperate) fisheries, resulting in potentially larger long-term changes to the ecosystem structure and functioning. The results indicate a very inefficient utilization of the food energy value of marine production. Rebuilding overfished components of the ecosystem and changing focus to balancing exploitation across a wider range of TLs, i.e. balanced harvesting, has the potential to significantly increase overall catches from global marine fisheries.
Therapeutic potential of regulatory cytokines that target B cells
Authors: Fujio Keishi , Okamura Tomohisa , Sumitomo , Shuji , Yamamoto Kazuhiko
Published: December 2015

Autoreactive B cells play a crucial role in the pathogenesis of autoimmune diseases by producing auto-antibodies and presenting antigens. Regulatory cytokines that simultaneously suppress multiple pathways have the potential to control autoreactive B cells. The generally inhibitory cytokine IL-10 may have a stimulatory effect on human B-cell survival and antibody production. TGF-β family cytokines can decrease or increase antibody production and can suppress B-cell proliferation and differentiation. In contrast to TGF-β1, which induces extensive fibrosis, TGF-β3 and bone morphogenetic protein 6 (BMP-6)/BMP-7 induce non-scarring wound healing and counteract tissue fibrosis. Therefore, TGF-β3 and BMP-6/BMP-7 may be clinically applicable as therapeutic cytokines that target B cells. Recent progress in protein engineering may enable us to generate novel biologic therapies based on TGF-β family cytokines.
Pharmacology
Authors: Kelly Ugarte Lauren R. , Agne Daniel , Park Chul-Kyun
Published: December 2015

This chapter contains 53 questions relevant for the Pediatric Subspecialty Exam about the topic of pharmacology.
Endocrine/Metabolic System
Authors: Maass Birgit
Published: December 2015

This chapter contains 25 questions relevant for the Pediatric Subspecialty Exam about the topic of the endocrine/metabolic system.
Fluid, Electrolyte, and Temperature Management
Authors: Sullivan Cornelius , Brustowicz Robert
Published: December 2015

This chapter contains 20 questions relevant for the Pediatric Subspecialty Exam about the topic of fluid management and patient positioning.
Postoperative Period
Authors: Downey Laura A. , Ellinas Herodotos , Bilge Aykut
Published: December 2015

This chapter contains 18 questions relevant for the Pediatric Subspecialty Exam about the topic of postoperative periods.
Professional Issues
Authors: Manuel Solmaz P. , Mai Christine L.
Published: December 2015

The scope of professional issues in pediatric anesthesia presents challenges for the anesthesiologist because the care involves both the child and the family. Ethical issues can arise with questions about informed consent, informed permission, and assent in minors. Children of Jehovah’s Witnesses parents can present ethical challenges for the anesthesiologist. The Institute of Medicine’s (IOM) 1999 report, “To Err Is Human: Building a Safer Health System,” brought attention to the problem of preventable medical errors occurring in US hospitals each year. These errors resulted in up to 98,000 patient deaths and were more likely to occur in operating rooms, emergency departments, and intensive care units. The report called for a comprehensive effort by health care providers, government, and consumers to make drastic reductions in these errors. Patient safety and quality assurance have become pinnacle motivators for anesthesiologists to strive for quality improvement in patient care.
Epidemiology and Risk Factors for Echinocandin Nonsusceptible Candida glabrata Bloodstream Infections: Data From a Large Multisite Population-Based Candidemia Surveillance Program, 2008–2014
Authors: Vallabhaneni Snigdha , Cleveland Angela A. , Farley Monica M. , Harrison Lee H. , Schaffner William , Beldavs Zintar G. , Derado Gordana , Pham Cau D. , Lockhart Shawn R. , Smith Rachel M.
Published: December 2015

Background.  Echinocandins are first-line treatment for Candida glabrata candidemia. Echinocandin resistance is concerning due to limited remaining treatment options. We used data from a multisite, population-based surveillance program to describe the epidemiology and risk factors for echinocandin nonsusceptible (NS) C glabrata candidemia.

Methods.  The Centers for Disease Control and Prevention's Emerging Infections Program conducts population-based laboratory surveillance for candidemia in 4 metropolitan areas (7.9 million persons; 80 hospitals). We identified C glabrata cases occurring during 2008–2014; medical records of cases were reviewed, and C glabrata isolates underwent broth microdilution antifungal susceptibility testing. We defined echinocandin-NS C glabrata (intermediate or resistant) based on 2012 Clinical and Laboratory Standards Institute minimum inhibitory concentration breakpoints. Independent risk factors for NS C glabrata were determined by stepwise logistic regression.

Results.  Of 1385 C glabrata cases, 83 (6.0%) had NS isolates (19 intermediate and 64 resistant); the proportion of NS isolates rose from 4.2% in 2008 to 7.8% in 2014 (P < .001). The proportion of NS isolates at each hospital ranged from 0% to 25.8%; 3 large, academic hospitals accounted for almost half of all NS isolates. In multivariate analysis, prior echinocandin exposure (adjusted odds ratio [aOR], 5.3; 95% CI, 2.6–1.2), previous candidemia episode (aOR, 2.5; 95% CI, 1.2–5.1), hospitalization in the last 90 days (aOR, 1.9; 95% CI, 1.0–3.5, and fluconazole resistance [aOR, 3.6; 95% CI, 2.0–6.4]) were significantly associated with NS C glabrata. Fifty-nine percent of NS C glabrata cases had no known prior echinocandin exposure.

Conclusion.  The proportion of NS C glabrata isolates rose significantly during 2008–2014, and NS C glabrata frequency differed across hospitals. In addition to acquired resistance resulting from prior drug exposure, occurrence of NS C glabrata without prior echinocandin exposure suggests possible transmission of resistant organisms.
India’s Soft Power
Authors: Mullen Rani D.
Published: December 2015

Indian foreign policy is increasingly drawing on a perception of its rising soft power. If effective, it should make global partners more open to Indian views and interests. However, significant impediments remain to cementing India’s fragile gains in leveraging its soft power on the global stage. Its assets include its ancient and distinct cultural heritage, the Bollywood film industry, and its status as the world’s largest democracy, albeit one that is developing and changing rapidly. The government’s increasing foreign assistance and public diplomacy programs are soft power instruments. It nevertheless remains unclear whether New Delhi can translate these assets into increasing the influence of India in policy circles internationally and among the broader international publics. For this to happen, India must design and resource coherent strategies for promoting its soft power abroad at the same time as it addresses domestic challenges that reflect little credit on it internationally.
The Media in the Making of Indian Foreign Policy
Authors: Joshi Manoj
Published: December 2015

The media has often been called the fourth estate, or the fourth branch of the government, for the role it plays in the societal and political life of a country. Through the medium of newspapers, TV, and now the Internet, it not just informs, but also influences public opinion and through that, the government, to adopt, reject, or modify a chosen policy direction. While there are other means through which people make informed choices on domestic policy, the media plays a significantly larger role when it comes to foreign policy. This chapter seeks to establish just what kind of a role the Indian media plays in the making of foreign policy, discussing also influences over its content, not least those relating to media ownership in India.
Theorizing India’s Foreign Relations
Authors: Mallavarapu Siddharth
Published: December 2015

The objective of this chapter is to attempt a best case argument for Indian theorizing on Indian foreign policy. This chapter explores early writings on Indian foreign policy and their theoretical underpinnings. While not consciously invoking the conventional registers of mainstream IR theorizing, some key figures in the first generation of disciplinary international studies in India sought to approach the world on their own terms. In this chapter the author grapples with what might be gained from engaging these early accounts. While the general lament remains that generically foreign policy has been under-theorized, the author points to research directions that might nudge future scholars in the field to pay greater heed to context and local accents, introduce a stronger comparative dimension, and systematically pursue theoretical openings made possible by a closer reading of the first generation of Indian international relations writings on foreign policy.
India–Sri Lanka Equation
Authors: Suryanarayan V.
Published: December 2015

This chapter provides an overview of India–Sri Lanka relations since the dawn of independence. Being a small country, bordering on a colossus, it is natural that Sri Lanka should entertain fears about the intentions and objectives of its northern neighbour. Very often, the Sinhalese elite, in order to limit Indian influence, tries to involve external powers, which contribute to the worsening of India–Sri Lanka relations. Significant highlights in the chapter include: problems of stateless people, delimitation of the maritime boundary, New Delhi’s policy towards ethnic conflict, the India–Sri Lanka Accord and the 13th Amendment, the refugee phenomenon, the travails of fishermen, and India–Sri Lanka economic cooperation. The full potential of India–Sri Lanka relations can be accomplished only when the ruling elite view geography as an opportunity and not as a hindrance.