bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the excitation frequency on the density of helium metastable atoms in an atmospheric pressure dielectric barrier discharge
Authors: Boisvert J.-S. , Sadeghi N. , Margot J. , Massines F.
Published: January 2017

Diffuse dielectric barrier discharges in atmospheric-pressure helium can be sustained over a wide range of excitation frequencies (from, but not restricted, 25 kHz to 15 MHz). The aim of the present paper is to identify the specific characteristics of the discharge modes that can be sustained in this frequency range, namely, the atmospheric-pressure Townsend-like discharge (APTD-L) mode, the atmospheric-pressure glow discharge (APGD) mode, the Ω mode, the hybrid mode, and the RF-α mode. This is achieved experimentally, by measuring the density of helium metastable atoms, which are known to play a driving role on the discharge kinetics. This density is measured by means of two absorption spectroscopy methods, one using a spectral lamp and the other one using a diode laser as a light source. The first one provides the time-averaged atom densities in the singlet He(21S) and triplet He(23S) metastable states, while with the second one we access the time-resolved density of He(23S) atoms. Time-averaged measurements indicate that the He(23S) density is relatively low in the APTD-L, the Ω and the RF-α modes (<4×1016 m−3) slightly higher in the APGD mode (2–7×1016 m−3), and still higher (>1×1017 m−3) in the hybrid mode. The hybrid mode is exclusively observed for frequencies from 0.2 to 3 MHz. However, time-resolved density measurement shows that at 1 MHz and below, the hybrid mode is not continuously sustained. Instead, the discharge oscillates between the Ω and the hybrid mode with a switching frequency about the kilohertz. This explains the significantly lower power required to sustain the plasma as compared to above 1 MHz.
A grand canonical Monte Carlo study of SO2 capture using functionalized bilayer graphene nanoribbons
Authors: Maurya Manish , Singh Jayant K.
Published: January 2017

Grand canonical Monte Carlo (GCMC) simulation is used to study the adsorption of pure SO2 using a functionalized bilayer graphene nanoribbon (GNR) at 303 K. The functional groups considered in this work are OH, COOH, NH2, NO2, and CH3. The mole percent of functionalization considered in this work is in the range of 3.125%–6.25%. GCMC simulation is further used to study the selective adsorption of SO2 from binary and ternary mixtures of SO2, CO2, and N2, of variable composition using the functionalized bilayer graphene nanoribbon at 303 K. This study shows that the adsorption and selectivity of SO2 increase after the functionalization of the nanoribbon compared to the hydrogen terminated nanoribbon. The order of adsorption capacity and selectivity of the functionalized nanoribbon is found to follow the order COOH > NO2 > NH2 > CH3 > OH > H. The selectivity of SO2 is found to be maximum at a pressure less than 0.2 bar. Furthermore, SO2 selectivity and adsorption capacity decrease with increase in the molar ratio of SO2/N2 mixture from 1:1 to 1:9. In the case of ternary mixture of SO2, CO2, N2, having compositions of 0.05, 0.15, 0.8, the selectivity of SO2 over N2 is higher than that of CO2 over N2. The maximum selectivity of SO2 over CO2 is observed for the COOH functionalized GNR followed by NO2 and other functionalized GNRs.
Aggregation state and magnetic properties of magnetite nanoparticles controlled by an optimized silica coating
Authors: Pérez Nicolás , Moya C. , Tartaj P. , Labarta A. , Batlle X.
Published: January 2017

The control of magnetic interactions is becoming essential to expand/improve the applicability of magnetic nanoparticles (NPs). Here, we show that an optimized microemulsion method can be used to obtain homogenous silica coatings on even single magnetic nuclei of highly crystalline Fe3−xO4 NPs (7 and 16 nm) derived from a high-temperature method. We show that the thickness of this coating is controlled almost at will allowing much higher average separation among particles as compared to the oleic acid coating present on pristine NPs. Magnetic susceptibility studies show that the thickness of the silica coating allows the control of magnetic interactions. Specifically, as this effect is better displayed for the smallest particles, we show that dipole-dipole interparticle interactions can be tuned progressively for the 7 nm NPs, from almost non-interacting to strongly interacting particles at room temperature. The quantitative analysis of the magnetic properties unambiguously suggests that dipolar interactions significantly broaden the effective distribution of energy barriers by spreading the distribution of activation magnetic volumes.
A comparative study on continuous and pulsed RF argon capacitive glow discharges at low pressure by fluid modeling
Authors: Liu Ruiqiang , Liu Yue , Jia Wenzhu , Zhou Yanwen
Published: January 2017

Based on the plasma fluid theory and using the drift-diffusion approximation, a mathematical model for continuous and pulsed radial frequency (RF) argon capacitive glow discharges at low pressure is established. The model is solved by a finite difference method and the numerical results are reported. Based on the systematic analysis of the results, plasma characteristics of the continuous and pulsed RF discharges are comparatively investigated. It is shown that, under the same condition for the peak value of the driving potential, the cycle-averaged electron density, the current density, and other essential physical quantities in the continuous RF discharge are higher than those from the pulsed RF discharge. On the other hand, similar plasma characteristics are obtained with two types of discharges, by assuming the same deposited power. Consequently, higher driving potential is needed in pulsed discharges in order to maintain the same effective plasma current. Furthermore, it is shown that, in the bulk plasma region, the peak value of the bipolar electric field from the continuous RF discharge is greater than that from the pulsed RF discharge. In the sheath region, the ionization rate has the shape of double-peaking and the explanation is given. Because the plasma input power depends on the driving potential and the plasma current phase, the phase differences between the driving potential and the plasma current are compared between the continuous and the pulsed RF discharges. It is found that this phase difference is smaller in the pulsed RF discharge compared to that of the continuous RF discharge. This means that the input energy coupling in the pulsed RF discharge is less efficient than the continuous counterpart. This comparative study, carried out also under other conditions, thus can provide instructive ideas in applications using the continuous and pulsed RF capacitive glow discharges.
A N = 2 extension of the Hirota bilinear formalism and the supersymmetric KdV equation
Authors: Delisle Laurent
Published: January 2017

We present a bilinear Hirota representation of the N = 2 supersymmetric extension of the Korteweg-de Vries equation. This representation is deduced using binary Bell polynomials, hierarchies, and fermionic limits. We, also, propose a new approach for the generalisation of the Hirota bilinear formalism in the N = 2 supersymmetric context.
Observation of decreasing resistivity of amorphous indium gallium zinc oxide thin films with an increasing oxygen partial pressure
Authors: Singh Anup K. , Adhikari Sonachand , Gupta Rajeev , Deepak
Published: January 2017

We have investigated the electrical resistivity behavior in amorphous indium gallium zinc oxide (a-IGZO) thin films. It is well known that resistivity increases as the film is deposited at a higher and higher oxygen partial pressure; we also record the same. However, in process we have discovered a remarkable region, in the oxygen deficient condition, that the resistivity shows an inverse behavior. This leads to the possibility that resistive films, suitable for thin film transistors, can also be obtained in oxygen deficient deposition conditions. Optical spectroscopic investigation could discern between a-IGZO films grown in oxygen deficient and oxygen rich conditions. The related resistivity behavior could be correlated to the presence of sub-bandgap states in films deposited in oxygen deficiency. These subgap states appear to be due to defects arising from local variations around the cations or oxygen atoms. The likely cause is an increase in Ga relative to In around O atom and the nature of cation-cation interaction when an oxygen atom is missing.
High-k perovskite gate oxide BaHfO3
Authors: Kim Young Mo , Park Chulkwon , Ha Taewoo , Kim Useong , Kim Namwook , Shin Juyeon , Kim Youjung , Yu Jaejun , Kim Jae Hoon , Char Kookrin
Published: January 2017

We have investigated epitaxial BaHfO3 as a high-k perovskite dielectric. From x-ray diffraction measurement, we confirmed the epitaxial growth of BaHfO3 on BaSnO3 and MgO. We measured optical and dielectric properties of the BaHfO3 gate insulator; the optical bandgap, the dielectric constant, and the breakdown field. Furthermore, we fabricated a perovskite heterostructure field effect transistor using epitaxial BaHfO3 as a gate insulator and La-doped BaSnO3 as a channel layer on SrTiO3 substrate. To reduce the threading dislocations and enhance the electrical properties of the channel, an undoped BaSnO3 buffer layer was grown on SrTiO3 substrates before the channel layer deposition. The device exhibited a field effect mobility value of 52.7 cm2 V−1 s−1, a Ion/Ioff ratio higher than 107, and a subthreshold swing value of 0.80 V dec−1. We compare the device performances with those of other field effect transistors based on BaSnO3 channels and different gate oxides.
Synthesized MoSe2/TiO2 heterogeneous structure as the promising photocatalytic material: Studies from theory to experiment
Authors: Lei Xiang , Yu Ke , Tang Zheng , Zhu Ziqiang
Published: January 2017

An excellent photocatalyst has been successfully achieved by synthesizing a MoSe2/TiO2 heterostructure. The density functional theory was employed to accurately describe the impact of composited MoSe2 by comparing the electronic structure, band position, and distribution of charge carriers between the MoSe2/TiO2 heterostructure and bare TiO2/MoSe2. The calculation results illustrate that the inhibitory effect of the electron-hole pair recombination can be promoted in the obtained heterostructure, which was experimentally verified by photoluminescence. The photodegradation of methylene blue demonstrated that the enhanced photocatalysis originates from the modulated carrier behavior due to MoSe2 composition. This work presents a good candidate for the application of the photocatalytic process and enriches our understanding of the electronic structure of TMDs-/TiO2-based heterojunction composites.
Performance comparison between rotor flux-switching and stator flux-switching machines considering local demagnetization
Authors: Su Peng , Hua Wei
Published: January 2017

This paper investigates the local permanent magnet (PM) demagnetization characteristics of stator-PM flux-switching (SPM-FS) machine and rotor-PM flux-switching (RPM-FS) machine. The partial demagnetization mechanisms of two machines are analyzed based on a simple magnetic circuit method, and verified by finite-element analysis (FEA). In addition, the performance degradation due to demagnetization effect is evaluated, and a comprehensive comparison of a pair of three-phase prototyped machines is conducted, where the two machines have the same stator outer diameter, stack length and rated current density. The predicted results indicate the demagnetization is generated in the corner parts of PMs near to air-gap for SPM-FS machines, and then the torque performances are degraded, while PMs in RPM-FS machine are hardly influenced by demagnetization effect. Hence, the anti-demagnetization capability of the RPM-FS machine is significantly stronger than that of the SPM-FS machine.
Correlation between laser-induced damage densities of fused silica and average incubation fluences at 1064 nm in the nanosecond regime
Authors: Lamaignère L. , Diaz R. , Chambonneau M. , Grua P. , Natoli J.-Y. , Rullier J.-L.
Published: January 2017

The chronology of the physical processes involved in the nanosecond laser damage of fused silica is investigated at 1064 nm. From experiments realized with multiple longitudinal mode pulses, the correspondence between ring pattern damage morphology and the corresponding intensity profile allows the distinction of two damage phases: an incubation phase followed by a damage expansion phase that leads to the final damage diameter. It allows us to determine both the incubation and the expansion fluences. These results are compared to damage density measurements for different laser configurations, different optics, and different environments. It was found that damage densities were as high as incubation fluences were low. This approach shows a deterministic part of laser damage in nanosecond regime and contributes to reinforce the statistical results by reducing their random nature and is more able to guide the physical interpretations of laser damage experiments.
Vector network analyzer measurement of the amplitude of an electrically excited surface acoustic wave and validation by X-ray diffraction
Authors: Camara I. S. , Croset B. , Largeau L. , Rovillain P. , Thevenard L. , Duquesne J.-Y.
Published: January 2017

Surface acoustic waves are used in magnetism to initiate magnetization switching, in microfluidics to control fluids and particles in lab-on-a-chip devices, and in quantum systems like two-dimensional electron gases, quantum dots, photonic cavities, and single carrier transport systems. For all these applications, an easy tool is highly needed to measure precisely the acoustic wave amplitude in order to understand the underlying physics and/or to optimize the device used to generate the acoustic waves. We present here a method to determine experimentally the amplitude of surface acoustic waves propagating on Gallium Arsenide generated by an interdigitated transducer. It relies on Vector Network Analyzer measurements of S parameters and modeling using the Coupling-Of-Modes theory. The displacements obtained are in excellent agreement with those measured by a very different method based on X-ray diffraction measurements.
Shock-induced migration of Σ3〈110〉 grain boundaries in Cu
Authors: Long X. J. , Wang L. , Li B. , Zhu J. , Luo S. N.
Published: January 2017

Using molecular dynamics simulations, we systematically investigate shock-induced migration of a set of Σ3〈110〉70.53° tilt grain boundaries in Cu, including coherent twin boundary, 15 asymmetric tilt grain boundaries (ATGBs), and symmetric incoherent twin boundary (SITB), with inclination angle (Φ) increasing from 0° to 90°. Grain boundary migration occurs only in ATGBs, via faceting for Φ≤70.53° and translation for Φ>70.53° (with the 9R phase). Migration magnitude increases with increasing Φ for ATGBs. Migration mode and magnitude depend on the grain boundary structure including SITB orientation and length fraction, and the symmetry of resolved shear stress distribution across a grain boundary.
Investigation of gate leakage current mechanism in AlGaN/GaN high-electron-mobility transistors with sputtered TiN
Authors: Li Y. , Ng G. I. , Arulkumaran S. , Ye G. , Liu Z. H. , Ranjan K. , Ang K. S.
Published: January 2017

The gate leakage current mechanism of AlGaN/GaN Schottky barrier diodes (SBDs) and high-electron-mobility transistors (HEMTs) with sputtered TiN is systematically investigated. The reverse leakage current (JR) of TiN SBDs increases exponentially with the increase of reverse voltage (VR) from 0 to −3.2 V (Reg. I). This conduction behavior is dominated by Poole-Frenkel emission from TiN through an interface state of 0.53 eV to the conductive dislocation-related continuum states. The obtained interface state of 0.53 eV may be due to the plasma damage to the surface of the AlGaN/GaN HEMT structure during the TiN sputtering. When the TiN SBDs are biased with −20 < VR < −3.2 V, JR saturated due to the depletion of the 2-dimensional electron gas (2DEG) channel (Reg. II). This conduction behavior is dominated by the trap-assisted tunneling through the interface state at ∼0.115 eV above the Fermi level. The three terminal OFF-state gate leakage current of AlGaN/GaN HEMTs exhibited an activation energy of 0.159 eV, which is in close agreement with the obtained interface state of ∼0.115 eV from saturated JR (Reg. II) of the SBDs. The observation of the negative temperature coefficient (−1.75 V/K) from the OFF-state breakdown voltage (at 1 μA/mm) of AlGaN/GaN HEMTs is due to the trap-assisted tunneling mechanism, which is also well correlated with the conduction mechanism realized from the reverse leakage current of the SBDs.
On the electrostatic control achieved in transistors based on multilayered MoS2: A first-principles study
Authors: Lu Anh Khoa Augustin , Pourtois Geoffrey , Luisier Mathieu , Radu Iuliana P. , Houssa Michel
Published: January 2017

In this work, the electrostatic control in metal-oxide-semiconductor field-effect transistors based on MoS2 is studied, with respect to the number of MoS2 layers in the channel and to the equivalent oxide thickness of the gate dielectric, using first-principles calculations combined with a quantum transport formalism. Our simulations show that a compromise exists between the drive current and the electrostatic control on the channel. When increasing the number of MoS2 layers, a degradation of the device performances in terms of subthreshold swing and OFF currents arises due to the screening of the MoS2 layers constituting the transistor channel.
Strain powered antennas
Authors: Domann John P. , Carman Greg P.
Published: January 2017

This paper proposes the creation of strain powered antennas that radiate electromagnetic energy by mechanically vibrating a piezoelectric or piezomagnetic material. A closed form analytic model of electromagnetic radiation from a strain powered electrically small antenna is derived and analyzed. Fundamental scaling laws and the frequency dependence of strain powered antennas are discussed. The radiation efficiency of strain powered electrically small antennas is contrasted with a conventional electric dipole. Analytical results show that operating at the first mechanical resonance produces the most efficient strain powered radiation relative to electric dipole antennas. A resonant analysis is exploited to determine the material property space that produces efficient strain powered antennas. These results show how a properly designed strain powered antenna can radiate more efficiently than an equally sized electric dipole antenna.
Precession-torque-driven domain-wall motion in out-of-plane materials
Authors: Peeters M. J. G. , Ummelen F. C. , Lalieu M. L. M. , Kim J.-S. , Swagten H. J. M. , Koopmans B.
Published: January 2017

Domain-wall (DW) motion in magnetic nanostrips is intensively studied, in particular because of the possible applications in data storage. In this work, we will investigate a novel method of DW motion using magnetic field pulses, with the precession torque as the driving mechanism. We use a one dimensional (1D) model to show that it is possible to drive DWs in out-of-plane materials using the precession torque, and we identify the key parameters that influence this motion. Because the DW moves back to its initial position at the end of the field pulse, thereby severely complicating direct detection of the DW motion, depinning experiments are used to indirectly observe the effect of the precession torque. The 1D model is extended to include an energy landscape in order to predict the influence of the precession torque in the depinning experiments. Although preliminary experiments did not yet show an effect of the precession torque, our calculations indicate that depinning experiments can be used to demonstrate this novel method of DW motion in out-of-plane materials, which even allows for coherent motion of multiple domains when the Dzyaloshinskii-Moriya interaction is taken into account.
Improvement of the transport properties of a high-mobility electron system by intentional parallel conduction
Authors: Peters S. , Tiemann L. , Reichl C. , Fält S. , Dietsche W. , Wegscheider W.
Published: January 2017

We present a gating scheme to separate even strong parallel conduction from the magneto-transport signatures and properties of a two-dimensional electron system. By varying the electron density in the parallel conducting layer, we can study the impact of mobile charge carriers in the vicinity of the dopant layer on the properties of the two-dimensional electron system. It is found that the parallel conducting layer is indeed capable to screen the remote ionized impurity potential fluctuations responsible for the fragility of fractional quantum Hall states.
Mid-IR colloidal quantum dot detectors enhanced by optical nano-antennas
Authors: Yifat Yuval , Ackerman Matthew , Guyot-Sionnest Philippe
Published: January 2017

We report the fabrication of a colloidal quantum dot based photodetector designed for the 3–5 μm mid infrared wavelength range incorporated with optical nano-antenna arrays to enhance the photocurrent. The fabricated arrays exhibit a resonant behavior dependent on the length of the nano-antenna rods, in good agreement with numerical simulation. The device exhibits a three-fold increase in the spectral photoresponse compared to a photodetector device without antennas, and the resonance is polarized parallel to the antenna orientation. We numerically estimate the device quantum efficiency and investigate its bias dependence.
High performance top-gated ferroelectric field effect transistors based on two-dimensional ZnO nanosheets
Authors: Tian Hongzheng , Wang Xudong , Zhu Yuankun , Liao Lei , Wang Xianying , Wang Jianlu , Hu Weida
Published: January 2017

High quality ultrathin two-dimensional zinc oxide (ZnO) nanosheets (NSs) are synthesized, and the ZnO NS ferroelectric field effect transistors (FeFETs) are demonstrated based on the P(VDF-TrFE) polymer film used as the top gate insulating layer. The ZnO NSs exhibit a maximum field effect mobility of 588.9 cm2/Vs and a large transconductance of 2.5 μS due to their high crystalline quality and ultrathin two-dimensional structure. The polarization property of the P(VDF-TrFE) film is studied, and a remnant polarization of >100 μC/cm2 is achieved with a P(VDF-TrFE) thickness of 300 nm. Because of the ultrahigh remnant polarization field generated in the P(VDF-TrFE) film, the FeFETs show a large memory window of 16.9 V and a high source-drain on/off current ratio of more than 107 at zero gate voltage and a source-drain bias of 0.1 V. Furthermore, a retention time of >3000 s of the polarization state is obtained, inspiring a promising candidate for applications in data storage with non-volatile features.
The impact of fluid flow on force chains in granular media
Authors: Mahabadi Nariman , Jang Jaewon
Published: January 2017

Fluid flow through granular media is an important process found in nature and various engineering applications. The effect of fluid flow on the evolution of force chains in the granular media is explored using the photoelasticity theory. A transparent cell is designed to contain several photoelastic disks of different sizes and to allow fluid flow through the particle packing. Water is injected into the cell while the particle packing is under confining stress. Several images are taken for the conditions of different confining stresses and fluid injection rates. An algorithm of an image processing technique is developed to detect the orientation and magnitude of contact forces. The results show that forces in parallel and transverse to the flow direction increase with increasing water velocity, while parallel force shows a higher increasing rate.
Influence of the ac-Stark shift on GPS atomic clock timekeeping
Authors: Formichella V. , Camparo J. , Tavella P.
Published: January 2017

The ac-Stark shift (or light shift) is a fundamental aspect of the field/atom interaction arising from virtual transitions between atomic states, and as Alfred Kastler noted, it is the real-photon counterpart of the Lamb shift. In the rubidium atomic frequency standards (RAFS) flying on Global Positioning System (GPS) satellites, it plays an important role as one of the major perturbations defining the RAFS' frequency: the rf-discharge lamp in the RAFS creates an atomic signal via optical pumping and simultaneously perturbs the atoms' ground-state hyperfine splitting via the light shift. Though the significance of the light shift has been known for decades, to date there has been no concrete evidence that it limits the performance of the high-quality RAFS flying on GPS satellites. Here, we show that the long-term frequency stability of GPS RAFS is primarily determined by the light shift as a consequence of stochastic jumps in lamplight intensity. Our results suggest three paths forward for improved GPS system timekeeping: (1) reduce the light-shift coefficient of the RAFS by careful control of the lamp's spectrum; (2) operate the lamp under conditions where lamplight jumps are not so pronounced; and (3) employ a light source for optical pumping that does not suffer pronounced light jumps (e.g., a diode laser).
Guanylate-binding protein 1 (GBP1) contributes to the immunity of human mesenchymal stromal cells against
Toxoplasma gondii
Authors: Qin Aiping , Lai De-Hua , Liu Qifa , Huang Weijun , Wu Ya-Ping , Chen Xiaoyong , Yan Sunxing , Xia Huimin , Hide Geoff , Lun Zhao-Rong , Ayala Francisco J. , Xiang Andy Peng
Published: January 2017

Significance

Mesenchymal stem cells (MSCs) are thought to be derived from pericytes and exhibit a cellular, autonomous antimicrobial effector function that provides therapeutic potential against infectious diseases. However, the molecular mechanism remains unknown. Here, we demonstrate that human guanylate-binding protein 1 (hGBP1) is a key protective factor against
Toxoplasma gondii
infection in human MSCs (hMSCs). The recruitment of hGBP1 to the parasitophorous vacuole membrane in IFN-γ–stimulated hMSCs significantly inhibited
T. gondii
replication. Thus, our current study reveals an important function of hGBP1 in the defense against
T. gondii
and may shed new light on clarifying the mechanism of host defense properties of hMSCs.
Antagonists of growth hormone-releasing hormone inhibit proliferation induced by inflammation in prostatic epithelial cells
Authors: Popovics Petra , Schally Andrew V. , Salgueiro Luis , Kovacs Krisztina , Rick Ferenc G.
Published: January 2017

Significance

The current therapeutic approaches to the treatment of benign prostatic hyperplasia (BPH) do not take into consideration that inflammation is an important factor in the pathogenesis of this disease. We previously demonstrated that growth hormone-releasing hormone (GHRH) antagonists reduce prostatic weights and decrease the level of inflammatory cytokines in a testosterone-induced BPH model. This study sheds light on the paracrine roles of GHRH in prostatic inflammation and demonstrates that GHRH stimulates the growth of BPH-1 and primary prostate epithelial spheres and that GHRH antagonists reduce prostate volume in an experimental model of prostatic inflammation.
Reported threats
Authors: Berk-Seligson Susan , Seligson Mitchell A.
Published: January 2017

This study offers new insights into the complex and underexplored nature of reported threats. Combining the theoretical framework of speech act analysis with the concept of reported speech, the study finds six categories of reported threats, uncovering ones that have been overlooked by existing scholarship thus far. The texts presented are derived from audio-recordings of 847 interviews carried out in four Central American countries: El Salvador, Honduras, Guatemala, and Panama between 2010 and 2014. References to threats and threat narratives came from school teachers, community leaders, police officers, clergy, and members of municipal violence prevention committees. The interpretation of indirect and implicit threats are made in the social context of communities under siege, that is, under constant attack by local gangs, many of whom are connected to national gangs and international narcotrafficking cartels. The credibility of the different types of threats is evaluated, using Goffman’s (1981) insight into the complexity of speaker roles in face-to-face interaction.
ERBIN deficiency links STAT3 and TGF-β pathway defects with atopy in humans
Authors: Lyons J.J. , Liu Y. , Ma C.A. , Yu X. , O’Connell M.P. , Lawrence M.G. , Zhang Y. , Karpe K. , Zhao M. , Siegel A.M. , Stone K.D. , Nelson C. , Jones N. , DiMaggio T. , Darnell D.N. , Mendoza-Caamal E. , Orozco L. , Hughes J.D. , McElwee J. , Hohman R.J. , Frischmeyer-Guerrerio P.A. , Rothenberg M.E. , Freeman A.F. , Holland S.M. , Milner J.D.
Published: January 2017

Nonimmunological connective tissue phenotypes in humans are common among some congenital and acquired allergic diseases. Several of these congenital disorders have been associated with either increased TGF-β activity or impaired STAT3 activation, suggesting that these pathways might intersect and that their disruption may contribute to atopy. In this study, we show that STAT3 negatively regulates TGF-β signaling via ERBB2-interacting protein (ERBIN), a SMAD anchor for receptor activation and SMAD2/3 binding protein. Individuals with dominant-negative STAT3 mutations (STAT3mut) or a loss-of-function mutation in ERBB2IP (ERBB2IPmut) have evidence of deregulated TGF-β signaling with increased regulatory T cells and total FOXP3 expression. These naturally occurring mutations, recapitulated in vitro, impair STAT3–ERBIN–SMAD2/3 complex formation and fail to constrain nuclear pSMAD2/3 in response to TGF-β. In turn, cell-intrinsic deregulation of TGF-β signaling is associated with increased functional IL-4Rα expression on naive lymphocytes and can induce expression and activation of the IL-4/IL-4Rα/GATA3 axis in vitro. These findings link increased TGF-β pathway activation in ERBB2IPmut and STAT3mut patient lymphocytes with increased T helper type 2 cytokine expression and elevated IgE.
Sequestration of cholesterol within the host late endocytic pathway restricts liver-stagePlasmodiumdevelopment
Authors: Petersen Wiebke , Stenzel Werner , Silvie Olivier , Blanz Judith , Saftig Paul , Matuschewski Kai , Ingmundson Alyssa
Published: January 2017

While lysosomes are degradative compartments and one of the defenses against invading pathogens, they are also hubs of metabolic activity. Late endocytic compartments accumulate around Plasmodium berghei liver-stage parasites during development, and whether this is a host defense strategy or active recruitment by the parasites is unknown. In support of the latter hypothesis, we observed that the recruitment of host late endosomes (LEs) and lysosomes is reduced in uis4−parasites, which lack a parasitophorous vacuole membrane protein and arrest during liver-stage development. Analysis of parasite development in host cells deficient for late endosomal or lysosomal proteins revealed that the Niemann–Pick type C (NPC) proteins, which are involved in cholesterol export from LEs, and the lysosome-associated membrane proteins (LAMP) 1 and 2 are important for robust liver-stage P. berghei growth. Using the compound U18666A, which leads to cholesterol sequestration in LEs similar to that seen in NPC- and LAMP-deficient cells, we show that the restriction of parasite growth depends on cholesterol sequestration and that targeting this process can reduce parasite burden in vivo. Taken together, these data reveal that proper LE and lysosome function positively contributes to liver-stage Plasmodium development.
Method to study cell migration under uniaxial compression
Authors: Srivastava Nishit , Kay Robert R. , Kabla Alexandre J.
Published: January 2017

The chemical, physical, and mechanical properties of the extracellular environment have a strong effect on cell migration. Aspects such as pore size or stiffness of the matrix influence the selection of the mechanism used by cells to propel themselves, including by pseudopods or blebbing. How a cell perceives its environment and how such a cue triggers a change in behavior are largely unknown, but mechanics is likely to be involved. Because mechanical conditions are often controlled by modifying the composition of the environment, separating chemical and physical contributions is difficult and requires multiple controls. Here we propose a simple method to impose a mechanical compression on individual cells without altering the composition of the matrix. Live imaging during compression provides accurate information about the cell's morphology and migratory phenotype. Using Dictyostelium as a model, we observe that a compression of the order of 500 Pa flattens the cells under gel by up to 50%. This uniaxial compression directly triggers a transition in the mode of migration from primarily pseudopodial to bleb driven in <30 s. This novel device is therefore capable of influencing cell migration in real time and offers a convenient approach with which to systematically study mechanotransduction in confined environments.
Eugenics: A Very Short introduction
Authors: Levine Philippa
Published: January 2017

The word “eugenics” was coined in 1883 by Francis Galton to express his dream of perfecting the human race by applying the laws of genetic heredity. Eugenics: A Very Short Introduction tackles the intricate and controversial history of eugenics. It synthesizes the enormous range of policies and experiments carried out in the name of eugenics around the world throughout the twentieth century. It questions the widespread belief that eugenics disappeared after World War II and evaluates the impact of eugenics on current reproductive and genetic sciences. Charting the development of such controversial practices as artificial insemination, sperm donation, and population control, this VSI offers a timely reflection on the frequent interplay between genetics and ethics.
The southern leading and trailing wraps of the Sagittarius tidal stream around the globular cluster Whiting 1
Authors: Carballo-Bello J. A. , Corral-Santana J. M. , Martínez-Delgado D. , Sollima A. , Muñoz R. R. , Côté P. , Duffau S. , Catelan M. , Grebel E. K.
Published: January 2017

We present a study of the kinematics of 101 stars observed with VIsible MultiObject Spectrograph around Whiting 1, a globular cluster embedded in the Sagittarius tidal stream. The obtained velocity distribution shows the presence of two wraps of that halo substructure at the same heliocentric distance as that of the cluster and with well-differentiated mean radial velocities. The most prominent velocity component seems to be associated with the trailing arm of Sagittarius with 〈vr〉 ∼ −130 km s−1, which is consistent with the velocity of Whiting 1. This result supports that this globular cluster was formed in Sagittarius and recently accreted by the Milky Way. The second component with 〈vr〉 ∼ 120 km s−1 might correspond to the leading arm of Sagittarius, which has been predicted by numerical simulations but with no conclusive observational evidence of its existence presented so far. This detection of the old leading wrap of Sagittarius in the Southern hemisphere may be used to confirm and further constrain the models for its orbit and evolution.
The ALMA view of W33A: a spiral filament feeding the candidate disc in MM1-Main
Authors: Maud L. T. , Hoare M. G. , Galván-Madrid R. , Zhang Q. , de Wit W. J. , Keto E. , Johnston K. G. , Pineda J. E.
Published: January 2017

We targeted the massive star-forming region W33A using the Atacama large sub/millimeter array in bands 6 (230 GHz) and 7 (345 GHz) to search for a sub-1000 au disc around the central O-type massive young stellar object W33A MM1-Main. Our data achieve a resolution of ∼0.2 arcsec (∼500 au) and resolve the central core, MM1, into multiple components and reveal complex and filamentary structures. There is strong molecular line emission covering the entire MM1 region. The kinematic signatures are inconsistent with only Keplerian rotation although we propose that the shift in the emission line centroids within ∼1000 au of MM1-Main could hint at an underlying compact disc with Keplerian rotation. We cannot however rule out the possibility of an unresolved binary or multiple system. A putative smaller disc could be fed by the large-scale spiral ‘feeding filament’ we detect in both gas and dust emission. We also discuss the nature of the now-resolved continuum sources.
New quantum chemical computations of formamide deuteration support gas-phase formation of this prebiotic molecule
Authors: Skouteris D. , Vazart F. , Ceccarelli C. , Balucani N. , Puzzarini C. , Barone V.
Published: January 2017

Based on recent work, formamide might be a potentially very important molecule in the emergence of terrestrial life. Although detected in the interstellar medium for decades, its formation route is still debated, whether in the gas phase or on the dust grain surfaces. Molecular deuteration has proven to be, in other cases, an efficient way to identify how a molecule is synthesized. For formamide, new published observations towards the IRAS16293-2422 B hot corino show that its three deuterated forms have all the same deuteration ratio, 2–5 per cent and that this is a factor of 3–8 smaller than that measured for H2CO towards the IRAS16293-2422 protostar. Following a previous work on the gas-phase formamide formation via the reaction NH2 + H2CO → HCONH2 + H, we present here new calculations of the rate coefficients for the production of monodeuterated formamide through the same reaction, starting from monodeuterated NH2 or H2CO. Some misconceptions regarding our previous treatment of the reaction are also cleared up. The results of the new computations show that, at the 100 K temperature of the hot corino, the rate of deuteration of the three forms is the same, within 20 per cent. On the contrary, the reaction between non-deuterated species proceeds three times faster than that with deuterated ones. These results confirm that a gas-phase route for the formation of formamide is perfectly in agreement with the available observations.
GOOD VISUAL OUTCOME IN A BILATERAL MULTIFOCAL SYPHILITIC CHORIORETINITIS, DESPITE LATE DIAGNOSIS
Authors: de Aragao Ricardo Evangelista Marrocos , Barreira Ieda Maria Alexandre , Muccioli Cristina , Carneiro Gustavo Jose Arruda Mendes , de Araujo Cesar Pereira , de Almeida Everton Fernandes Vieira , Oria Talles Peterson Cavalcante , Pinto Nayara Queiroz Cardoso , Ferreira Jhonatan de Paula Araujo
Published: January 2017

Purpose:

To report a case of a good visual outcome in a patient with bilateral multifocal syphilitic chorioretinitis, despite the late diagnosis.

Methods:

Ophthalmologic examination, multimodal imaging, including fundus photography, angiography, and optical coherence tomography.

Results:

The authors describe a 47-year-old heterosexual man with a bilateral multifocal syphilitic chorioretinitis that was lately diagnosed and despite that had a good visual outcome.

Conclusion:

The diagnosis of ocular syphilis is a challenge; however, once it has been made, even lately, it is eminently treatable.
The Perinatal Birth Environment
Authors: Sommerness Samantha A. , Gams Rebecca , Rauk Phillip N. , Bangdiwala Ananta , Landers Daniel V. , Avery Melissa D. , Hirt Charles , Miller Kristi , Millar Amy , Cho Suzin , Shields Andrea
Published: January 2017

Key to any perinatal safety initiative is buy-in and strong leadership from obstetric and pediatric providers, advanced practice nurses, and labor and delivery nurses in collaboration with ancillary staff. In the fall of 2007, executives of a large Midwestern hospital system created the Zero Birth Injury Initiative. This multidisciplinary group sought to eliminate birth injury using the Institute of Healthcare Improvement Perinatal Bundles. Concurrently, the team implemented a standardized second-stage labor guideline for women who choose epidural analgesia for pain management to continue the work of eliminating birth injuries in second-stage labor. The purpose of this article was to describe the process of the modification and adaptation of a standardized second-stage labor guideline, as well as adherence rates of these guidelines into clinical practice. Prior to implementation, a Web-based needs assessment survey of providers was conducted. Most (77% of 180 respondents) believed there was a need for an evidence-based guideline to manage the second stage of labor. The guideline was implemented at 5 community hospitals and 1 academic health center. Data were prospectively collected during a 3-month period for adherence assessment at 1 community hospital and 1 academic health center. Providers adhered to the guideline in about 57% of births. Of patients whose provider followed the guideline, 75% of women were encouraged to delay pushing compared with only 28% of patients delayed pushing when the provider did not follow the guideline.
Creating a Holding Environment for Caregivers
Authors: Warren Inga
Published: January 2017

The quality of care that families and infants receive during their time on the neonatal unit will be influenced by the well-being of the people who care for them. The emotional work of caring for infants and families in this demanding setting often goes unrecognized and can result in stress, burnout, and compassion fatigue, which in turn are a threat to the quality of care. Resilience and well-being can be fostered by encouraging self-maintenance, supportive systems organization, providing a healthy working environment, education, and opportunities for reflection.
Longitudinal Responses to Weighing and Bathing Procedures in Preterm Infants
Authors: Bembich Stefano , Fiani Giulia , Strajn Tamara , Sanesi Cecilia , Demarini Sergio , Sanson Gianfranco
Published: January 2017

Knowledge of the effects of nursing-induced stress on short-term outcomes in preterm infants is limited. Effects of 2 standard nursing procedures—weighing and bathing—on autonomic and motor stability of preterm infants were studied during their hospitalization. Outcomes were evaluated during and after the procedures. Eleven preterm infants were observed between 32 and 35 weeks' postmenstrual age (PMA) (postnatal days range: 4–63). Neonatal responses were assessed according to the Synactive Theory of Development and nursing was performed taking into account Newborn Individualized Developmental Care and Assessment Program (NIDCAP) principles. Effects of the studied nursing procedures on infants' stability during and after their execution were evaluated by nonparametric statistics. During monitored procedures, stress responses in autonomic and motor systems were observed at all PMAs. However, after 32 weeks' PMA, preterm infants also showed an autonomic and motor stability recovery 5 minutes after procedure completion. Contrary to our hypothesis, preterm infants showed to be stressed by weighing and bathing procedures up to 35 weeks' PMA. However, if facilitated and supported after nursing conclusion by interventions such as swaddling and nesting, according to NIDCAP principles, they recovered autonomic and motor stability by 5 minutes after ending procedures.
Striving for Optimum Noise-Decreasing Strategies in Critical Care
Authors: Disher Timothy C. , Benoit Britney , Inglis Darlene , Burgess Stacy A. , Ellsmere Barbara , Hewitt Brenda E. , Bishop Tanya M. , Sheppard Christopher L. , Jangaard Krista A. , Morrison Gavin C. , Campbell-Yeo Marsha L.
Published: January 2017

To identify baseline sound levels, patterns of sound levels, and potential barriers and facilitators to sound level reduction. The study setting was neonatal and pediatric intensive care units in a tertiary care hospital. Participants were staff in both units and parents of currently hospitalized children or infants. One 24-hour sound measurements and one 4-hour sound measurement linked to observed sound events were conducted in each area of the center's neonatal intensive care unit. Two of each measurement type were conducted in the pediatric intensive care unit. Focus groups were conducted with parents and staff. Transcripts were analyzed with descriptive content analysis and themes were compared against results from quantitative measurements. Sound levels exceeded recommended standards at nearly every time point. The most common code was related to talking. Themes from focus groups included the critical care context and sound levels, effects of sound levels, and reducing sound levels—the way forward. Results are consistent with work conducted in other critical care environments. Staff and families realize that high sound levels can be a problem, but feel that the culture and context are not supportive of a quiet care space. High levels of ambient sound suggest that the largest changes in sound levels are likely to come from design and equipment purchase decisions. L
10 and L
max appear to be the best outcomes for measurement of behavioral interventions.
Clinical and Morphologic Features of ETV6-NTRK3 Translocated Papillary Thyroid Carcinoma in an Adult Population Without Radiation Exposure
Authors: Seethala Raja R. , Chiosea Simion I. , Liu Cheng Z. , Nikiforova Marina , Nikiforov Yuri E.
Published: January 2017

The ETV6-NTRK3 translocation characterizes a subset of radiation associated and pediatric papillary thyroid carcinomas (PTCs). We now describe the clinicopathologic features of ETV6-NTRK3 translocated PTC in an adult population without radiation exposure. Twelve cases were identified by next-generation sequencing (ThyroSeq version 2). The mean patient age was 37 years with a female predilection (10:2). Preoperative fine needle aspiration was performed on 6 patients of which 4 were classified as “malignant,” whereas 2 were classified as “follicular lesion of undetermined significance.” One third (4/12) of patients demonstrated extrathyroidal extension and one half of patients (5/10) demonstrated lymph node metastases. One patient presented with brain metastasis. Tumors typically (8/12) demonstrated an admixture of follicular and papillary patterns and were usually infiltrative and multinodular (6/12 cases). Tumors often showed clear cell or oncocytic foci and demonstrated overt nuclear features of PTC, though characteristically, interspersed bland areas were common, even in metastases. Cytoplasmic vacuolization resembling that of mammary analog secretory carcinoma was also common but focal. TTF-1 was positive and S100 was negative in all tested cases confirming a thyroid phenotype. Unique morphologies included glomeruloid follicles, reverse polarization of nuclei. Survey of the TCGA datasets revealed similar findings. Thus, ETV6-NTRK3 translocated PTC are locoregionally aggressive and can metastasize distantly. They are characterized by mixture of papillary and follicular architecture and may show cytoplasmic vacuolization akin to other ETV6 translocated carcinomas. Although nuclear features are typically overt, interspersed bland regions may cause diagnostic difficulty in metastatic sites, and may explain discordance on fine needle aspiration.