bluuebunny/crossref_metadata_2025 huggingface dataset:
Turbulence statistics in smooth wall oscillatory boundary layer flow
Authors: van der A Dominic A. , Scandura Pietro , O’Donoghue Tom
Published: June 2018

Turbulence characteristics of an asymmetric oscillatory boundary layer flow are analysed through two-component laser-Doppler measurements carried out in a large oscillatory flow tunnel and direct numerical simulation (DNS). Five different Reynolds numbers, $R_{\unicode[STIX]{x1D6FF}}$, in the range 846–2057 have been investigated experimentally, where $R_{\unicode[STIX]{x1D6FF}}=\tilde{u} _{0max}\unicode[STIX]{x1D6FF}/\unicode[STIX]{x1D708}$ with $\tilde{u} _{0max}$ the maximum oscillatory velocity in the irrotational region, $\unicode[STIX]{x1D6FF}$ the Stokes length and $\unicode[STIX]{x1D708}$ the fluid kinematic viscosity. DNS has been carried out for the lowest three $R_{\unicode[STIX]{x1D6FF}}$ equal to 846, 1155 and 1475. Both experimental and numerical results show that the flow statistics increase during accelerating phases of the flow and especially at times of transition to turbulent flow. Once turbulence is fully developed, the near-wall statistics remain almost constant until the late half-cycle, with values close to those reported for steady wall-bounded flows. The higher-order statistics reach large values within a normalized wall distance of approximately $y/\unicode[STIX]{x1D6FF}=0.2$ at phases corresponding to the onset of low-speed streak breaking, because of the intermittency of the velocity fluctuations at these times. In particular, the flatness of the streamwise velocity fluctuations reaches values of the order of ten, while the flatness of the wall-normal velocity fluctuations reaches values of several hundreds. Far from the wall, at locations where the vertical gradient of the streamwise velocity is zero, the skewness is approximately zero and the flatness is approximately equal to 3, representative of a normal distribution. At lower elevations the distribution of the fluctuations deviate substantially from a normal distribution, but are found to be well described by other standard theoretical probability distributions.
Viscous fingering in a radial elastic-walled Hele-Shaw cell
Authors: Pihler-Puzović Draga , Peng Gunnar G. , Lister John R. , Heil Matthias , Juel Anne
Published: June 2018

We study the viscous-fingering instability in a radial Hele-Shaw cell in which the top boundary has been replaced by a thin elastic sheet. The introduction of wall elasticity delays the onset of the fingering instability to much larger values of the injection flow rate. Furthermore, when the instability develops, the fingers that form on the expanding air–liquid interface are short and stubby, in contrast with the highly branched patterns observed in rigid-walled cells (Pihler-Puzović et al., Phys. Rev. Lett., vol. 108, 2012, 074502). We report the outcome of a comprehensive experimental study of this problem and compare the experimental observations to the predictions from a theoretical model that is based on the solution of the Reynolds lubrication equations, coupled to the Föppl–von-Kármán equations which describe the deformation of the elastic sheet. We perform a linear stability analysis to study the evolution of small-amplitude non-axisymmetric perturbations to the time-evolving base flow. We then derive a simplified model by exploiting the observations (i) that the non-axisymmetric perturbations to the sheet are very small and (ii) that perturbations to the flow occur predominantly in a small wedge-shaped region ahead of the air–liquid interface. This allows us to identify the various physical mechanisms by which viscous fingering is weakened (or even suppressed) by the presence of wall elasticity. We show that the theoretical predictions for the growth rate of small-amplitude perturbations are in good agreement with experimental observations for injection flow rates that are slightly larger than the critical flow rate required for the onset of the instability. We also characterize the large-amplitude fingering patterns that develop at larger injection flow rates. We show that the wavenumber of these patterns is still well predicted by the linear stability analysis, and that the length of the fingers is set by the local geometry of the compliant cell.
Sedimentation of a surfactant-laden drop under the influence of an electric field
Authors: Poddar Antarip , Mandal Shubhadeep , Bandopadhyay Aditya , Chakraborty Suman
Published: June 2018

The sedimentation of a surfactant-laden deformable viscous drop acted upon by an electric field is considered theoretically. The convection of surfactants in conjunction with the combined effect of electrohydrodynamic flow and sedimentation leads to a locally varying surface tension, which subsequently alters the drop dynamics via the interplay of Marangoni, Maxwell and hydrodynamic stresses. Assuming small capillary number and small electric Reynolds number, we employ a regular perturbation technique to solve the coupled system of governing equations. It is shown that when a leaky dielectric drop is sedimenting in another leaky dielectric fluid, the Marangoni stress can oppose the electrohydrodynamic motion severely, thereby causing corresponding changes in the internal flow pattern. Such effects further result in retardation of the drop settling velocity, which would have otherwise increased due to the influence of charge convection. For non-spherical drop shapes, the effect of Marangoni stress is overcome by the ‘tip-stretching’ effect on the flow field. As a result, the drop deformation gets intensified with an increase in sensitivity of the surface tension to the local surfactant concentration. Consequently, for an oblate type of deformation the elevated drag force causes a further reduction in velocity. For similar reasons, prolate drops experience less drag and settle faster than the surfactant-free case. In addition to this, with increased sensitivity of the interfacial tension to the surfactant concentration, the asymmetric deformation about the equator gets suppressed. These findings may turn out to be of fundamental significance towards designing electrohydrodynamically actuated droplet-based microfluidic systems that are intrinsically tunable by varying the surfactant concentration.
Reduced plasma concentration of branched-chain amino acids in sarcopenic older subjects: a cross-sectional study
Authors: Ottestad Inger , Ulven Stine M. , Øyri Linn K. L. , Sandvei Kristin S. , Gjevestad Gyrd O. , Bye Asta , Sheikh Navida A. , Biong Anne S. , Andersen Lene F. , Holven Kirsten B.
Published: June 2018

Branched-chain amino acids (BCAA) are essential amino acids that are necessary for muscle mass maintenance. Little is known about the plasma concentrations of BCAA and the protein intake in relation to sarcopenia. We aimed to compare the non-fasting plasma concentrations of the BCAA and the dietary protein intake between sarcopenic and non-sarcopenic older adults. Norwegian older home-dwelling adults (≥70 years) were invited to a cross-sectional study with no other exclusion criteria than age. Sarcopenic subjects were defined by the diagnostic criteria by the European Working Group on Sarcopenia in Older People. Non-fasting plasma concentrations of eight amino acids were quantified using NMR spectroscopy. Protein intake was assessed using 2×24-h dietary recalls. In this study, ninety out of 417 subjects (22 %) were sarcopenic, and more women (32 %) than men (11 %) were sarcopenic (P<0·0001). Sex-adjusted non-fasting plasma concentrations of leucine and isoleucine, and the absolute intake of protein (g/d), were significantly lower among the sarcopenic subjects, when compared with non-sarcopenic subjects (P=0·003, P=0·026 and P=0·003, respectively). A similar protein intake was observed in the two groups when adjusted for body weight (BW) and sex (1·1 g protein/kg BW per d; P=0·50). We show that sarcopenia is associated with reduced non-fasting plasma concentration of the BCAA leucine and isoleucine, and lower absolute intake of protein. More studies are needed to clarify the clinical relevance of these findings, related to maintenance of muscle mass and prevention of sarcopenia.
The benign helminth Hymenolepis diminuta ameliorates chemically induced colitis in a rat model system
Authors: Jirků Pomajbíková Kateřina , Jirků Milan , Levá Jana , Sobotková Kateřina , Morien Evan , Parfrey Laura Wegener
Published: June 2018

The tapeworm Hymenolepis diminuta is a model for the impact of helminth colonization on the mammalian immune system and a candidate therapeutic agent for immune mediated inflammatory diseases (IMIDs). In mice, H. diminuta protects against models of inflammatory colitis by inducing a strong type 2 immune response that is activated to expel the immature worm. Rats are the definitive host of H. diminuta, and are colonized stably and over long time periods without harming the host. Rats mount a mild type 2 immune response to H. diminuta colonization, but this response does not generally ameliorate colitis. Here we investigate the ability of different life cycle stages of H. diminuta to protect rats against a model of colitis induced through application of the haptenizing agent dinitrobenzene sulphonic acid (DNBS) directly to the colon, and monitor rat clinical health, systemic inflammation measured by TNFα and IL-1β, and the gut microbiota. We show that immature H. diminuta induces a type 2 response as measured by increased IL-4, IL-13 and IL-10 expression, but does not protect against colitis. In contrast, rats colonized with mature H. diminuta and challenged with severe colitis (two applications of DNBS) have lower inflammation and less severe clinical symptoms. This effect is not related the initial type 2 immune response. The gut microbiota is disrupted during colitis and does not appear to play an overt role in H. diminuta-mediated protection.
HEALTH TECHNOLOGY ASSESSMENT METHODS GUIDELINES FOR MEDICAL DEVICES: HOW CAN WE ADDRESS THE GAPS? THE INTERNATIONAL FEDERATION OF MEDICAL AND BIOLOGICAL ENGINEERING PERSPECTIVE
Authors: Polisena Julie , Castaldo Rossana , Ciani Oriana , Federici Carlo , Borsci Simone , Ritrovato Matteo , Clark Daniel , Pecchia Leandro
Published: June 2018

Objectives:

Current health technology assessment (HTA) methods guidelines for medical devices may benefit from contributions by biomedical and clinical engineers. Our study aims to: (i) review and identify gaps in the current HTA guidelines on medical devices, (ii) propose recommendations to optimize the impact of HTA for medical devices, and (iii) reach a consensus among biomedical engineers on these recommendations.

Methods:

A gray literature search of HTA agency Web sites for assessment methods guidelines on devices was conducted. The International Federation of Medical and Biological Engineers (IFMBE) then convened a structured focus group, with experts from different fields, to identify potential gaps in the current HTA guidelines, and to develop recommendations to fill these perceived gaps. The thirty recommendations generated from the focus group were circulated in a Delphi survey to eighty-five biomedical and clinical engineers.

Results:

Thirty-two panelists, from seventeen countries, participated in the Delphi survey. The responses showed a strong agreement on twenty-seven of thirty recommendations. Some uncertainties remain about the methods to accurately assess the effectiveness and safety, and interoperability of a medical device with other devices or within the clinical setting.

Conclusions:

As medical devices differ from drug therapies, current HTA methods may not accurately reflect the conclusions of their assessment. Recommendations informed by the focus group discussions and Delphi survey responses aimed to address the perceived gaps, and to provide a more integrated approach in medical device assessments in combining engineering with other perspectives, such as clinical, economic, patient, human factors, ethical, and environmental.
Genotype replacement of the human parainfluenza virus type 2 in Croatia between 2011 and 2017 – the role of neutralising antibodies
Authors: Šantak M. , Lang Balija M. , Mlinarić Galinović G. , Ljubin Sternak S. , Vilibić-Čavlek T. , Tabain I.
Published: June 2018

Previously we reported on the HPIV2 genotype distribution in Croatia 2011–2014. Here we expand this period up to 2017 and confirm that G1a genotype has replaced G3 genotype from the period 2011–2014. Our hypothesis was that the G1a-to-G3 genotype replacement is an antibody-driven event. A cross-neutralisation with anti-HPIV2 sera specific for either G1a or G3 genotype revealed the presence of genotype-specific antigenic determinants. By the profound,in silicoanalyses three potential B cell epitopic regions were identified in the hemagglutinin neuraminidase (regions 314–361 and 474–490) and fusion protein (region 440–484). The region identified in the fusion protein does not show any unique site between the G1a and G3 isolates, five differentially glycosylated sites in the G1a and G3 genotype isolates were identified in epitopic regions of hemagglutinin neuraminidase. All positively selected codons were found to be located either in the region 314–316 or in the region 474–490 what indicates a strong positive selection in this region and reveals that these regions are susceptible to evolutionary pressure possibly caused by antibodies what gives a strong verification to our hypothesis that neutralising antibodies are a key determinant in the inherently complex adaptive evolution of HPIV2 in the region.
Material Geographies of House Societies: Reconsidering Neolithic Çatalhöyük, Turkey
Authors: Kuijt Ian
Published: June 2018

This paper explores how people within Neolithic villages were connected to co-resident multi-family households, and considers the potential material footprint of multi-family households within Neolithic villages. Drawing upon data from Çatalhöyük, I suggest that Neolithic communities were organized around multiple competing and cooperating Houses, similar to House Societies, where house members resided in clusters of abutting buildings, all largely the same size and with similar internal organization. These space were deeply connected to telling the generative narratives of the House as a historical and genealogical social unit, including the lives and actions of the ancestors, and in some cases embedding them physically within the fabric of the building. Çatalhöyük multi-family House members decorated some important rooms with display elaboration that focused on the past, the future and the family, while the dead from the households, who in many ways were still alive and part of the ancestral House, lived beneath the floor. This study underlines that researchers need to consider social scales beyond the single-family household and consider how the multi-family House existed as an organizational foundation within Neolithic villages.
Effects of day length on pollen tube elongation, embryo formation and seed development after flowering in quinoa (Chenopodium quinoa Willd.)
Authors: Isobe Katsunori , Sugiyama Hikaru , Tamamushi Katsura , Shimizu Taito , Kobashi Kana , Higo Masao
Published: June 2018

The objective of this study was to evaluate the effect of day length after flowering on pollen tube elongation, embryo formation and seed development. The quinoa varieties used in this study were Amarilla de Marangani (valley type) and NL-6 (sea-level type). After sowing, the quinoa plants were cultivated in growth cabinets. From sowing to flowering, plants were exposed to a 15 h day length regime. After flowering, the plants were grown under either a 15 h or 11 h day length regime. The elongation of the pollen tube and the formation of the early embryo were not inhibited in either Amarilla de Marangani or NL-6 under the 11 or 15 h day length regimes. Although growth of the embryo in NL-6 was not inhibited by the 15 h day length regime after flowering, the same was not observed in the case for Amarilla de Marangani. In Amarilla de Marangani, seed diameter at 8 and 14 days after flowering under the 11 h day length regime was larger than that of seeds grown under the 15 h day length regime. Thus, the decrease in the number of seeds in Amarilla de Marangani grown under the 15 h day length regime may be caused by the suspension of embryo growth after fertilization.
Impact of a gestational exposure to diesel exhaust on offspring gonadal development: experimental study in the rabbit
Authors: Bourdon M. , Torres-Rovira L. , Monniaux D. , Faure C. , Levy R. , Tarrade A. , Rousseau-Ralliard D. , Chavatte-Palmer P. , Jolivet G.
Published: June 2018

The aim of the present work was to address experimentally the possible impact of exposure to air pollution during gestation on the differentiation and function of the gonads of the offspring using a rabbit model. Rabbits were exposed daily to diluted diesel exhaust gas or filtered air from the 3rd until the 27th day of gestation, during which time germ cells migrate in genital ridges and divide, and fetal sex is determined. Offspring gonads were collected shortly before birth (28th day of gestation) or after puberty (7.5 months after birth). The structure of the gonads was analyzed by histological and immunohistological methods. Serum concentrations of testosterone and anti-Müllerian hormone were determined using ELISA. The morphology and the endocrine function of the gonads collected just at the arrest of the exposure were similar in polluted and control animals in both sexes. No differences were observed as well in gonads collected after puberty. Sperm was collected at the head of the epididymis in adults. Sperm motility and DNA fragmentation were measured. Among all parameters analyzed, only the sperm DNA fragmentation rate was increased three-fold in exposed males. Mechanisms responsible for these modifications and their physiological consequences are to be further clarified.
Psychotherapie psychotischer Störungen
Authors: Lamster Fabian , Jäger Matthias
Published: June 2018

Zusammenfassung. Die Wirksamkeit von Psychotherapie bei Menschen mit psychotischen Störungen ist gut belegt und ­deren Anwendung wird von internationalen Leitlinien empfohlen. Zielsetzungen der psychotherapeutischen Interventionen sind Symptomreduktion, Rückfallprophylaxe, Verbesserung der kognitiven, emotionalen und sozialen Fertigkeiten, der gesellschaftlichen Integration und Teilhabe sowie der Lebenszufriedenheit und des Selbstbildes. Insbesondere kognitiv-verhaltenstherapeutische Ansätze, Familieninterventionen, kognitives und soziales Training sowie Psychoedukation sind gemäss Fachliteratur für die Behandlung von Psychosen geeignet. Eine tragfähige therapeutische Beziehung, ein patientengerechtes Behandlungssetting sowie eine gute Abstimmung mit anderen Interventionen im Rahmen eines multimodalen individuellen Therapiekonzepts sind grundlegende Faktoren für ein optimales Behandlungsergebnis. Für die zukünftige klinische Regelversorgung sowie die Versorgungsforschung stellt sich die Implementierung von evidenz-basierten psychotherapeutischen Interventionen als grosse Herausforderung dar.
Forensic Odontology: Automatic Identification of Persons Comparing Antemortem and Postmortem Panoramic Radiographs Using Computer Vision
Authors: Heinrich Andreas , Güttler Felix , Wendt Sebastian , Schenkl Sebastian , Hubig Michael , Wagner Rebecca , Mall Gita , Teichgräber Ulf
Published: June 2018

Purpose In forensic odontology the comparison between antemortem and postmortem panoramic radiographs (PRs) is a reliable method for person identification. The purpose of this study was to improve and automate identification of unknown people by comparison between antemortem and postmortem PR using computer vision.

Materials and Methods The study includes 43 467 PRs from 24 545 patients (46 % females/54 % males). All PRs were filtered and evaluated with Matlab R2014b including the toolboxes image processing and computer vision system. The matching process used the SURF feature to find the corresponding points between two PRs (unknown person and database entry) out of the whole database.

Results From 40 randomly selected persons, 34 persons (85 %) could be reliably identified by corresponding PR matching points between an already existing scan in the database and the most recent PR. The systematic matching yielded a maximum of 259 points for a successful identification between two different PRs of the same person and a maximum of 12 corresponding matching points for other non-identical persons in the database. Hence 12 matching points are the threshold for reliable assignment.

Conclusion Operating with an automatic PR system and computer vision could be a successful and reliable tool for identification purposes. The applied method distinguishes itself by virtue of its fast and reliable identification of persons by PR. This Identification method is suitable even if dental characteristics were removed or added in the past. The system seems to be robust for large amounts of data.

Key Points: 

Citation Format
Radical Addition/Cyclization Cascade: An Efficient Approach to Nitro-Containing Quinoline-2,4(1H,3H)-diones
Authors: Li Ya-Min , Yang Tao , Zhou Jia-Li , Li Junpeng , Shen Yuehai , Gao Chuanzhu
Published: June 2018

A radical addition/cyclization cascade of o-cyanoarylacrylamides with magnesium nitrate hexahydrate is developed. This reaction exhibits good functional group tolerance and wide substrate scope, provides a highly efficient and practical access to nitro-containing quinoline-2,4(1H,3H)-diones.
Approaches for Performing Reductions under Continuous-Flow Conditions
Authors: Riley Darren , Neyt Nicole
Published: June 2018

A concise overview of approaches to perform reductions of various functionalities including aldehydes, ketones, esters, imines, ­nitriles, nitro groups, alkenes and alkynes under continuous-flow conditions are highlighted and discussed in this short review.

1 Introduction

2 Reduction of Aldehydes, Ketones and Esters

3 Reduction of Imines and Nitriles

4 Reduction of Nitro Groups

5 Reduction of Alkenes

6 Partial Reduction of Alkynes

7 Conclusion
Thrombocytopenia and Platelet Dysfunction in Acute Tropical Infectious Diseases
Authors: Hapsari Putri Indri , Tunjungputri Rahajeng , De Groot Philip , van der Ven Andre , de Mast Quirijn
Published: June 2018

Thrombocytopenia is a well-known manifestation of acute tropical infectious diseases. The role of platelets in infections has received much attention recently because of their emerging activities in modulation of inflammatory responses, host defense, and vascular integrity. However, while many studies have addressed thrombocytopenia in tropical infections, abnormalities in platelet function have been largely overlooked. This is an important research gap, as platelet dysfunction may contribute to the bleeding tendency that characterizes some tropical infections. The development of novel platelet function assays that can be used in thrombocytopenic conditions (e.g., flow cytometry assays) has contributed to important new insights in recent years. In this review, the importance of platelets in tropical infections is discussed with special emphasis on the underlying mechanisms and consequences of thrombocytopenia and platelet dysfunction in these infections. Special attention is paid to malaria, a disease characterized by microvascular obstruction in which bleeding is rare, and to infections in which bleeding is common, such as dengue, other viral hemorrhagic fevers, and the bacterial infection leptospirosis. Given the importance of platelet function abnormalities in these infections, the development of affordable assays for monitoring of platelet function in low-resource countries, as well as pharmacologic interventions to prevent or reverse platelet function abnormalities, might improve clinical care and the prognosis of these infections.
Effects of plasma density on laser-generated energetic electron generation and transport in a plasma channel
Authors: Ji Yanling , Li Boyuan , Duan Tao , Zhou Weimin , Wu Fengjuan , Zhang Zhimeng , Ye Bin , Tang Yongjian
Published: June 2018

We use two-dimensional particle-in-cell simulations to investigate how the plasma density n0 of the channel target affects energetic-electron generation and transportation. The simulations show that the optimum plasma-density regime is 10 ≤ n0 ≤ 25 for the present simulation parameters, which results in a peak energy flux and coupling efficiency from laser to electrons. In this case, the laser beam propagates stably in the channel, which has the advantage of increasing the acceleration length and more effectively generating high-energy electrons. Furthermore, the high-current electron beam and the density modulation induce strong azimuthal magnetic fields and double-layer radial electric fields around the inner surface of the channel, which consistently guide and collimate the hot-electron bunch so that it propagates over rather long times and distances. Upon further increasing the plasma density n0, the hot electrons are scattered out of the channel by the damped laser pulse and the reduced quasistatic interface electromagnetic fields, reducing the long-time transport. The use of a proper plasma-density channel stably guides the relativistically intense laser pulse and greatly improves the properties of the electron beam.
Controlling the multi-electron dynamics in the high harmonic spectrum from N2O molecule using TDDFT
Authors: Monfared M. , Irani E. , Sadighi-Bonabi R.
Published: June 2018

In this study, high harmonic generation from a multi-atomic nitrous oxide molecule was investigated. A comprehensive three-dimensional calculation of the molecular dynamics and electron trajectories through an accurate time-dependent density functional theory was conducted to efficiently explore a broad harmonic plateau. The effects of multi-electron and inner orbitals on the harmonic spectrum and generated coherent attosecond pulses were analyzed. The role of the valence electrons in controlling the process and extending the harmonic plateau was investigated. The main issue of producing a super-continuum harmonic spectrum via a frequency shift was considered. The time-frequency representation by means of a wavelet transform of the induced dipole acceleration provided a good insight into the distorted effects from the nonlinear processes in high harmonic emission. The effect of the chirped laser pulse on the production of broadband amplitude was justified in this model. By adjusting the optimal laser parameters to an input intensity of 2.5 × 1014 W cm−2, an isolated 68 as pulse was generated.
The effect of surface roughness on rotor-stator cavity flows
Authors: Fernando D. , Gao S. , Garrett S. J.
Published: June 2018

We are concerned with the CFD simulation of annular rotor-stator cavities using the general purpose second-order finite volume method (FVM) solver OpenFOAM® and Large Eddy Simulation (LES) methods. Simulations of cavities with smooth surfaces are conducted at various Reynolds numbers, and the properties of the mean turbulent flows are validated against experimental and numerical data available in the literature. Comparisons show that second-order accurate FVM approaches can produce high-fidelity simulations of rotor-stator cavities to an acceptable accuracy and are therefore a viable alternative to the computationally intensive high-order methods. Our validated second-order FVM model is then combined with the parametric force approach of Busse and Sandham [“Parametric forcing approach to rough-wall turbulent channel flow,” J. Fluid Mech. 712, 169–202 (2012)] to simulate cavities with a rough rotor surface. Detailed flow visualisations suggest that roughness-induced disturbances propagate in the downstream direction of the rotor flow toward the outer wall of the cavity. The outer wall subsequently provides a passage to transport said roughness effects from the rough rotor layer to the smooth stator layer. We demonstrate that rotor-stator cavity flows are sensitive to even small roughness levels on the rotor surface alone.
Broadband voltage rectifier induced by linear bias dependence in CoFeB/MgO magnetic tunnel junctions
Authors: Tarequzzaman M. , Jenkins A. S. , Böhnert T. , Borme J. , Martins L. , Paz E. , Ferreira R. , Freitas P. P.
Published: June 2018

In this paper, perpendicular magnetic anisotropy (PMA) is tailored by changing the thickness of the free layer with the objective of producing MTJ nanopillars with a smooth linear resistance dependence with both the in-plane magnetic field and DC bias. We furthermore demonstrate how this linear bias dependence can be used to create a zero-threshold broadband voltage rectifier, a feature which is important for rectification in wireless charging and energy harvesting applications. By carefully balancing the amount of PMA acting in the free layer, the measured RF to DC voltage conversion efficiency can be made as large as 11%.
On the scattering correction of fast-ion D-alpha signals on NSTX-U
Authors: Hao G. Z. , Heidbrink W. W. , Liu D. , Stagner L. , Podestà M. , Bortolon A.
Published: June 2018

Analysis of fast-ion D-alpha (FIDA) data on National Spherical Torus Experiment-Upgrade (NSTX-U) shows that the cold Dα line contaminates the FIDA baseline. The scattered light is comparable to the FIDA emission. A scattering correction is required to extract the FIDA signal. Two methods that relate the scattered light contamination to the intensity of the cold Dα line are employed. One method uses laboratory measurements with a calibration lamp; the other method uses data acquired during plasma operation and singular value decomposition analysis. After correction, both the FIDA spectra and spatial profile are in better agreement with theoretical predictions.
Bubble dynamics and atomization mechanisms in burning multi-component droplets
Authors: Rao D. Chaitanya Kumar , Karmakar Srinibas , Basu Saptarshi
Published: June 2018

We examine the complete sequence of events associated with the transition in the topology of a single droplet into multiple fragments of secondary droplets in the context of burning multi-component miscible mixtures. The multi-component blends consist of tetradecane as a lower volatile component, while butanol and acetone-butanol-ethanol (A-B-E) are used as the higher volatile constituents. In addition to the widely recognized theory of bubble growth via micro-bubble coalescence, we reveal that the vapor bubble growth also occurs through the merging of large bubbles during the combustion of droplets. The initial bubble growth (Regime I) and collapse cycles were found to increase the rate of bubble nucleation in the droplet, which in turn leads to the growth and merging of two or more vapor bubbles into a single larger bubble (Regime II). The final stage of bubble growth (Regime III) is associated with the Rayleigh-Taylor (RT) instability at the vapor-liquid interface. After the inception of the RT instability, capillary wave propagation is also witnessed on the droplet surface. The breakup of a vapor bubble results in the creation of a ligament that subsequently undergoes pinch-off into one or more secondary droplets. The ligament pinch-off mechanisms are categorized into two types, i.e., tip breakup and tip-base breakup, which govern the diameter and velocity of secondary droplets along with succeeding volumetric shape oscillations in the parent droplet. In particular, the ligament tip-base pinch-off mechanism results in a bimodal distribution of secondary droplets. After the initial breakup event, a vapor bubble may grow either in the secondary droplet or inside the developing ligament, leading to a sequential cascade of breakup events.
Gravity of human impacts mediates coral reef conservation gains
Authors: Cinner Joshua E. , Maire Eva , Huchery Cindy , MacNeil M. Aaron , Graham Nicholas A. J. , Mora Camilo , McClanahan Tim R. , Barnes Michele L. , Kittinger John N. , Hicks Christina C. , D’Agata Stephanie , Hoey Andrew S. , Gurney Georgina G. , Feary David A. , Williams Ivor D. , Kulbicki Michel , Vigliola Laurent , Wantiez Laurent , Edgar Graham J. , Stuart-Smith Rick D. , Sandin Stuart A. , Green Alison , Hardt Marah J. , Beger Maria , Friedlander Alan M. , Wilson Shaun K. , Brokovich Eran , Brooks Andrew J. , Cruz-Motta Juan J. , Booth David J. , Chabanet Pascale , Gough Charlotte , Tupper Mark , Ferse Sebastian C. A. , Sumaila U. Rashid , Pardede Shinta , Mouillot David
Published: June 2018

Significance

Marine reserves that prohibit fishing are a critical tool for sustaining coral reef ecosystems, yet it remains unclear how human impacts in surrounding areas affect the capacity of marine reserves to deliver key conservation benefits. Our global study found that only marine reserves in areas of low human impact consistently sustained top predators. Fish biomass inside marine reserves declined along a gradient of human impacts in surrounding areas; however, reserves located where human impacts are moderate had the greatest difference in fish biomass compared with openly fished areas. Reserves in low human-impact areas are required for sustaining ecological functions like high-order predation, but reserves in high-impact areas can provide substantial conservation gains in fish biomass.
Human induced pluripotent stem cell-derived glial cells and neural progenitors display divergent responses to Zika and dengue infections
Authors: Muffat Julien , Li Yun , Omer Attya , Durbin Ann , Bosch Irene , Bakiasi Grisilda , Richards Edward , Meyer Aaron , Gehrke Lee , Jaenisch Rudolf
Published: June 2018

Significance

We describe the ability of the Zika virus to infect various cells of the fetal brain, modeled from induced pluripotent stem cells derived from a patient and grown in identical conditions. Zika is associated with microcephaly, while the similar dengue virus is not. We described differences in the behavior of these two viruses. Zika often fails to trigger efficient antiviral responses, surviving encounters with brain immune cells, and killing immature nerve cell precursors that have poor innate antiviral defenses. Precursors of the brain’s immune cells, microglia, circulating in the fetus, may take the virus to the fetal brain where it will stall growth or cause cell death. We show that interferon-γ efficiently protects against this viral transfer.
Microglia inhibit photoreceptor cell death and regulate immune cell infiltration in response to retinal detachment
Authors: Okunuki Yoko , Mukai Ryo , Pearsall Elizabeth A. , Klokman Garrett , Husain Deeba , Park Dong-Ho , Korobkina Ekaterina , Weiner Howard L. , Butovsky Oleg , Ksander Bruce R. , Miller Joan W. , Connor Kip M.
Published: June 2018

Significance

Photoreceptor cell death resulting from retinal detachment (RD) causes significant visual loss. While the immune system is activated during RD, its role is still unclear. Microglia are resident immune cells in the retina and are thought to be either protective or deleterious in response to neuronal injury, suggesting context-dependent effects. Here, we demonstrate that microglia limit retinal damage during acute injury, since microglial ablation led to increased photoreceptor death. Microglial morphological–activation changes triggered their migration into injured tissue where they formed intimate connections with infiltrating immune cells and phagocytized injured photoreceptors. These findings provide insight into the microglial response and function during RD, indicating microglia promote photoreceptor survival during acute phase injury by removing potentially damaging cell debris.
Reproduction in the Baka pygmies and drop in their fertility with the arrival of alcohol
Authors: Ramirez Rozzi Fernando V.
Published: June 2018

Significance

Humans are a polymorphic species with a broad geographical distribution. Diversity in growth and development plays an important role in biological adaptation and can be addressed through studies of life-history variation across different populations, particularly in hunter-gatherer societies. This paper reports the results from our study on fertility and mortality in the Baka pygmies based on individuals of known age. The Baka are characterized by low infant and juvenile mortalities, slow growth, and high fertility at an early age. However, the arrival of cheap alcohol has drastically reduced fertility early in life, which seriously compromises this population’s survival. We provide empirical evidence of the effects of alcohol consumption on the fertility rate of a hunter-gatherer society.
Genetic and developmental origins of a unique foraging adaptation in a Lake Malawi cichlid genus
Authors: Conith Moira R. , Hu Yinan , Conith Andrew J. , Maginnis Maura A. , Webb Jacqueline F. , Albertson R. Craig
Published: June 2018

Significance

Biologists have long been captivated by novel traits because they provide insights into both the origin of and constraints on morphological variation. The iconic adaptive radiations of cichlid fishes have led to incredible diversity of form, including some species with an exaggerated snout. This novelty is mechanically integrated with the upper jaw, appears to be under directional selection, and is found in one of the most ecologically successful cichlid lineages. We used protein manipulation, gene expression, and genetic mapping to implicate the Tgfβ pathway in the development of this unusual trait. Given the functions of Tgfβ signaling in tissue proliferation, migration, invasion, and organ fibrosis, this represents an example of the cooption of existing pathways in the evolution of novelty.
Coordinated prefrontal–hippocampal activity and navigation strategy-related prefrontal firing during spatial memory formation
Authors: Negrón-Oyarzo Ignacio , Espinosa Nelson , Aguilar-Rivera Marcelo , Fuenzalida Marco , Aboitiz Francisco , Fuentealba Pablo
Published: June 2018

Significance

Learning the location of relevant places is an iterative process in which animals gradually adjust and optimize their navigation patterns to reach the target. This cognitive operation requires the interplay between the hippocampus, which represents the animal’s current location, and the prefrontal cortex, which implements the selection of adaptive behavioral responses. Yet, how do these structures interact during spatial learning? By recording neural activity in freely behaving mice, we found that the prefrontal cortex and hippocampus gradually increase their oscillatory synchrony as learning progresses, whereas the firing patterns of prefrontal neurons represent the behavioral goal exclusively when the optimal trajectory is selected. These findings provide insight into the cortical dynamics underlying spatial learning.
A nonequilibrium force can stabilize 2D active nematics
Authors: Maitra Ananyo , Srivastava Pragya , Marchetti M. Cristina , Lintuvuori Juho S. , Ramaswamy Sriram , Lenz Martin
Published: June 2018

Significance

Living systems differ from dead matter in one crucial aspect: They are driven by internal engines. In anisotropic fluids, the widely accepted framework of active matter theory predicts that this necessarily leads to an instability from quiescence to large-scale and eventually incoherent motion. Here we challenge this common wisdom by reexamining the symmetries of the most ubiquitous experimental geometry for active systems. We uncover an additional coupling between activity and motion that can make an active system even more stable than its passive counterpart, while preserving other hallmarks of nonequilibrium physics. Our results challenge common views on active matter and clarify the interpretation of multiple experiments.
Ab initio spectroscopy and ionic conductivity of water under Earth mantle conditions
Authors: Rozsa Viktor , Pan Ding , Giberti Federico , Galli Giulia
Published: June 2018

Significance

Despite more than a century of study, the properties of water at high pressure and temperature remain difficult to measure. First-principles computations are ideal tools to study matter under extreme conditions, as they require neither assumptions about chemical bonds nor experimental data for fitting interatomic potentials. Here we carry out first-principles simulations to study the diffusivity, vibrational properties, and conductivity of water in a controversial region of its phase diagram (1,000 K, 10–20 GPa). Our results provide insight into water’s dissociation mechanism, the origin of its large ionic conductivity, and the spectroscopic signatures of ionic species. We predict Raman and infrared spectra at several conditions, which will serve as a guide for future experiments.
Inhibition of epithelial cell migration and Src/FAK signaling by SIRT3
Authors: Lee Jaewon J. , van de Ven Robert A. H. , Zaganjor Elma , Ng Mei Rosa , Barakat Amey , Demmers Joris J. P. G. , Finley Lydia W. S. , Gonzalez Herrera Karina N. , Hung Yin Pun , Harris Isaac S. , Jeong Seung Min , Danuser Gaudenz , McAllister Sandra S. , Haigis Marcia C.
Published: June 2018

Significance

Metastasis is the most common cause of cancer-related death. The function of reactive oxygen species (ROS) in metastasis is conflicting, and it has been observed to promote or inhibit metastasis. Thus, a more in-depth analysis is needed to assess the impact of ROS on metastasis. In this study, we find that local down-regulation of SIRT3 at the leading edge of migrating cells results in elevated ROS levels and activation of Src/focal adhesion kinase signaling. Further, collective cell migration and metastases formation are inhibited by SIRT3, while patient data sets point to an inverse correlation between SIRT3 and breast cancer metastasis.
Species-specific disruption of STING-dependent antiviral cellular defenses by the Zika virus NS2B3 protease
Authors: Ding Qiang , Gaska Jenna M. , Douam Florian , Wei Lei , Kim David , Balev Metodi , Heller Brigitte , Ploss Alexander
Published: June 2018

Significance

To shed light on the host range of Zika virus (ZIKV), we surveyed the virus’ ability to infect cells of evolutionarily diverse species. ZIKV replicates efficiently in human, great ape, Old and New World monkey, but not rodent cells. These observations correlated with ZIKV’s ability to blunt the cGAS/STING signaling pathway in all primate cells tested but not in mice. We demonstrate that an enzyme shared by many flaviviruses (NS2B3) is responsible for functionally inactivating this antiviral defense. Our results highlight the importance of the cGAS/STING pathway in shaping the host range of ZIKV, which in turn may guide the development of murine models with inheritable susceptibility to ZIKV and other flaviviruses.
Mechanistic insights into GLUT1 activation and clustering revealed by super-resolution imaging
Authors: Yan Qiuyan , Lu Yanting , Zhou Lulu , Chen Junling , Xu Haijiao , Cai Mingjun , Shi Yan , Jiang Junguang , Xiong Wenyong , Gao Jing , Wang Hongda
Published: June 2018

Significance

Many membrane proteins are functioning in aggregations and associating with microdomains, which range from nanometers to micrometers in size. Therefore, it is indispensable to directly analyze these proteins and microdomains in native cell membranes at a single-molecule level. GLUT1 is a ubiquitously expressed protein, contributing to basal and growth factor-stimulated glucose uptake in many tissues. It is overexpressed in almost all tumors. Herein, by direct stochastic optical reconstruction microscopy, we previously mapped GLUT1 on native cell membranes and highlighted key contributions of the lipid raft, cytoskeleton, and glycosylation to the formation of clusters. Moreover, we elucidated that the clustered distribution of the transporter was associated with its activation, which is crucial to advance our understanding of the transporter’s spatial organization and activation mechanism.
ANXA2 could act as a moderator of EGFR-directed therapy resistance in triple negative breast cancer
Authors: Zhang Yue , Bi Jiajia , Zhu Hongtao , Shi Mei , Zeng Xianlu
Published: June 2018

Triple negative breast cancer (TNBC) patients cannot benefit from EGFR-targeted therapy even though the EGFR is highly expressed, because patients exhibit resistance to these drugs. Unfortunately, the molecular mechanisms remain relatively unknown. ANXA2, highly expressed in invasive breast cancer cells, is closely related with poor prognosis, and acts as a molecular switch to EGFR activation. In this study, MDA-MB-231 cells and MCF7 cells were used. Our results showed that ANXA2 expression is inversely correlated with cell sensitivity to gefitinib. Knockdown of ANXA2 expression in MDA-MB-231 cells increased the gefitinib induced cell death. When ANXA2 was overexpressed in MCF7 cells, the gefitinib induced cell death was decreased. Furthermore, we demonstrated that phosphorylation of ANXA2 at Tyr23 is negatively correlated with the sensitivity of TNBC to gefitinib. Altogether, our results suggest a new role of ANXA2 in regulating sensitivity of TNBC MDA-MB-231 cells to the EGFR inhibitor gefitinib.
Sentential negation of abstract and concrete conceptual categories: a brain decoding multivariate pattern analysis study
Authors: Ghio Marta , Haegert Karolin , Vaghi Matilde M. , Tettamanti Marco
Published: June 2018

We rarely use abstract and concrete concepts in isolation but rather embedded within a linguistic context. To examine the modulatory impact of the linguistic context on conceptual processing, we isolated the case of sentential negation polarity, in which an interaction occurs between the syntactic operator
not
and conceptual information in the negation's scope. Previous studies suggested that sentential negation of concrete action-related concepts modulates activation in the fronto-parieto-temporal action representation network. In this functional magnetic resonance imaging study, we examined the influence of negation on a wider spectrum of meanings, by factorially manipulating sentence polarity (affirmative, negative) and fine-grained abstract (mental state, emotion, mathematics) and concrete (related to mouth, hand, leg actions) conceptual categories. We adopted a multivariate pattern analysis approach, and tested the accuracy of a machine learning classifier in discriminating brain activation patterns associated to the factorial manipulation. Searchlight analysis was used to localize the discriminating patterns. Overall, the neural processing of affirmative and negative sentences with either an abstract or concrete content could be accurately predicted by means of multivariate classification. We suggest that sentential negation polarity modulates brain activation in distributed representational semantic networks, through the functional mediation of syntactic and cognitive control systems.

This article is part of the theme issue ‘Varieties of abstract concepts: development, use and representation in the brain’.
Number concepts: abstract and embodied
Authors: Fischer Martin H. , Shaki Samuel
Published: June 2018

Numerical knowledge, including number concepts and arithmetic procedures, seems to be a clear-cut case for abstract symbol manipulation. Yet, evidence from perceptual and motor behaviour reveals that natural number knowledge and simple arithmetic also remain closely associated with modal experiences. Following a review of behavioural, animal and neuroscience studies of number processing, we propose a revised understanding of psychological number concepts as grounded in physical constraints, embodied in experience and situated through task-specific intentions. The idea that number concepts occupy a range of positions on the continuum between abstract and modal conceptual knowledge also accounts for systematic heuristics and biases in mental arithmetic, thus inviting psycho-logical approaches to the study of the mathematical mind.

This article is part of the theme issue ‘Varieties of abstract concepts: development, use and representation in the brain’.