bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of granular rheology in a quasi-two-dimensional slow flow by means of discrete element method based simulations
Authors: Bhateja Ashish , Khakhar Devang V.
Published: January 2020

The steady flow of spherical particles in a rectangular bin is studied using the discrete element method for different flow rates of the particles from the bin in the slow flow regime. The flow has two nonzero velocity components and is more complex than the widely studied unidirectional shear flows. The objective of the study is to characterize, in detail, the local rheology of the flowing material. The flow is shown to be of nearly constant density, with a symmetric stress tensor and the principal directions of the stress and rate of strain tensors being nearly colinear. The local rheology is analyzed using a coordinate transformation which enables direct computation of the viscosity and components of the pressure assuming the granular material to be a generalized Newtonian fluid. The scaled viscosity, fluctuation velocity, and volume fraction are shown to follow power law relations with the inertial number, a scaled shear rate, and data for different flow rates collapse to a single curve in each case. Results for flow of the particles on an inclined surface, presented for comparison, are similar to those for the bin flow but with a lower viscosity and a higher solid fraction due to layering of the particles. The in plane normal stresses are nearly equal and slightly larger than the third component. All three normal stresses correlate well with the corresponding fluctuation velocity components. Based on the empirical correlations obtained, a continuum model is presented for computation of granular flows.
Direct-imaging of light-driven colloidal Janus particles in weightlessness
Authors: Keßler R. , Bräuer D. , Dreißigacker C. , Drescher J. , Lozano C. , Bechinger C. , Born P. , Voigtmann Th.
Published: January 2020

We describe a highly integrated automated experiment module that allows us to investigate the active Brownian motion of light-driven colloidal Janus-particle suspensions. The module RAMSES (RAndom Motion of SElf-propelled particles in Space) is designed for the sounding rocket platform MAPHEUS (MAterialPHysikalische Experimente Unter Schwerelosigkeit). It allows us to perform experiments under weightlessness conditions in order to avoid sedimentation of the Janus particles and thus to study the spatially three-dimensional dynamics in the suspension. The module implements a newly developed strong homogeneous light source to excite self-propulsion in the Janus particles. The light source is realized through an array of high-power light-emitting diodes and replaces the conventional laser source, thus reducing heat dissipation and spatial extension of the experiment setup. The rocket module contains ten independent sample cells in order to ease the systematic study of the effect of control parameters such as light intensity or particle concentration and size in a single sounding-rocket flight. For each sample cell, transmitted light intensities are stored for postflight analysis in terms of differential dynamical microscopy.
Tuning electronic and optical properties of free-standing Sn2Bi monolayer stabilized by hydrogenation
Authors: Mohebpour Mohammad Ali , Vishkayi Sahar Izadi , Tagani Meysam Bagheri
Published: January 2020

In this study, we systematically investigated the structural, mechanical, electronic, and optical properties of the Sn2Bi monolayer, a sheet experimentally synthesized recently [Gou et al., Phys. Rev. Lett. 121, 126801 (2018)], which has been hydrogenated (Sn2BiH2) to stabilize free-standing form using density functional theory. For tuning the electronic properties, the mechanical strain and the electric field are used. Our investigations show that in this free-standing form, there are electron flatbands and free hole bands like the deposited sample on the silicon substrate, which provide the possibility of having strongly localized electrons and free holes. Also, the bandgap of the Sn2BiH2 monolayer has experienced a growth of 80% compared with the experimental sample. The strain-related results suggest that the bandgap can be properly manipulated within a range from 0.2 to 1.6 eV by biaxial strain (−13% to +21%). It should be mentioned that the stability and flexibility of the corresponding monolayer under tensile and compressive strain are due to the strong σ bonds between atoms. We also realized that the strain can cause indirect-direct transition in the bandgap. Furthermore, our optical findings indicate that the Sn2BiH2 monolayer has almost metallic properties in a specific range of the UV spectrum and it is transparent in the IR and visible spectra of electromagnetic radiation. All these tunable properties and nontrivial features portend that the Sn2BiH2 monolayer has great potential in applications as near-infrared detectors, thermoelectric devices, field-effect transistors, sensors, photocatalysis, energy harvesting, and optoelectronics.
Detection of spin-orbit torque with spin rotation symmetry
Authors: Wang Tao , Lendinez Sergi , Jungfleisch M. Benjamin , Kolodzey James , Xiao John Q. , Fan Xin
Published: January 2020

It has been recently demonstrated that spin–orbit coupling in ferromagnetic metals can generate spin current with symmetries different from the conventional spin Hall effect in nonmagnetic metals. The generated spin current can induce a spin–orbit torque on a neighboring magnetic layer with spin rotation symmetry. In this paper, we introduce a set of tools to measure this effect in a perpendicularly magnetized film, by using the second-order planar Hall effect method and spin-torque ferromagnetic resonance spectroscopy. These results are comparable to those detected by the polar magneto-optic Kerr effect technique.
New magnetic phases in thin terbium films
Authors: Sales F. H. S. , Oliveira L. L. , Dantas A. L. , Carriço A. S.
Published: January 2020

We report a theoretical investigation of new magnetic phases of thin terbium (Tb) films in the temperature interval between 220 K and 280 K, and under external magnetic field strengths ranging from 50 Oe to 1 kOe. We show that surface effects may produce relevant changes in the helimagnetic phase, such as the nucleation of alternating-helix phases. Changes in the exchange energy balance near the surface, favor the alignment with the external field and the nucleation of the alternating-helix phase.
Microtransformer on silicon with CoFeB magnetic core for high-frequency signal applications
Authors: Dinulovic Dragan , Shousha Mahmoud , Haug Martin
Published: January 2020

This paper presents the development, characterization and application of a microtransformer with a bar magnetic core fabricated on silicon substrate using thin-film technology. The magnetic core, coils, and insulation layers were deposited using only sputtering PVD (physical vapor deposition) or CVD (chemical vapor deposition) processes. As insulation materials, silicon dioxide and silicon nitride are only used. The device is small with a chip size of 1600 µm x 800 µm. The transformer has a turns ratio of 1:1 and achieves a self-inductance of about 40 nH. The minimum measured breakdown voltage of the microtransformer is 1250 V(DC). The microtransformer device is applicable for frequencies up to 20 MHz. The device was fabricated on 12-inch silicon substrates on mass production equipment.
Total-InGaN-thickness dependent Shockley-Read-Hall recombination lifetime in InGaN quantum wells
Authors: Zhou Renlin , Ikeda Masao , Zhang Feng , Liu Jianping , Zhang Shuming , Tian Aiqin , Wen Pengyan , Li Deyao , Zhang Liqun , Yang Hui
Published: January 2020

The mechanism behind the quantum-well-width dependent Shockley-Read-Hall (SRH) recombination lifetime is investigated in the InGaN/GaN quantum wells (QWs). According to the literature, the strong dependence of SRH lifetime on QW width is proposed to originate from the electron-hole separation in c-plane QWs, just as the radiative recombination. However, in this work, by temperature dependent steady-state time-resolved photoluminescence experiment, it is found that besides the QW width, the SRH lifetime also increases significantly with increasing QW number, which cannot be explained by the electron-hole separation. The two kinds of dependences of SRH lifetime can be attributed to the same source, judging from their similar activation energies, which is the existence of indium atoms compensating the SRH recombination centers generated during the epitaxy and thereby prolonging the SRH lifetime. The density of SRH centers deduced from our analysis decreases with the total thickness of the InGaN layer in a consistent manner for both the QW-width dependent and QW-number dependent sets of samples.
Optical clearing and shielding with fan-shaped vortex beams
Authors: Wang Haiping , Tang Liqin , Ma Jina , Hao Huiwen , Zheng Xiuyan , Song Daohong , Hu Yi , Li Yigang , Chen Zhigang
Published: January 2020

We propose and demonstrate a new method for creation of fan-shaped optical vortex beams by rational phase modulation and assembly based on a well-known conical vortex phase. Our design is different from the previously proposed method for generation of power-exponential vortex beams. Such unconventional vortex beams consist of multiple spiral beam filaments (as the fan blades), and their overall beam size and spiral angle can be readily controlled by adjusting the parameters. Experimentally, two examples of applications are illustrated with such fan-shaped vortex beams: one is optical clearing through densely scattering particle suspensions; the other is optical shielding and transporting a target particle from the suspensions by adding a donut pattern in the center (as the fan head). We envisage such specially designed fan beams may be used as a multifunctional tool for microfluidic and biological applications that involve the complex environment of the living bodies, especially for active isolation or separation of a trapped particle from fluid environments of high particle concentrations.
How entropic regression beats the outliers problem in nonlinear system identification
Authors: AlMomani Abd AlRahman R. , Sun Jie , Bollt Erik
Published: January 2020

In this work, we developed a nonlinear System Identification (SID) method that we called Entropic Regression. Our method adopts an information-theoretic measure for the data-driven discovery of the underlying dynamics. Our method shows robustness toward noise and outliers, and it outperforms many of the current state-of-the-art methods. Moreover, the method of Entropic Regression overcomes many of the major limitations of the current methods such as sloppy parameters, diverse scale, and SID in high-dimensional systems such as complex networks. The use of information-theoretic measures in entropic regression has unique advantages, due to the Asymptotic Equipartition Property of probability distributions, that outliers and other low-occurrence events are conveniently and intrinsically de-emphasized as not-typical, by definition. We provide a numerical comparison with the current state-of-the-art methods in sparse regression, and we apply the methods to different chaotic systems such as the Lorenz System, the Kuramoto-Sivashinsky equations, and the Double-Well Potential.
Perspective: Toward highly stable electroluminescent quantum dot light-emitting devices in the visible range
Authors: Davidson-Hall Tyler , Aziz Hany
Published: January 2020

With significant improvements in external quantum efficiency (EQE) and stability for red, green, and blue devices over the past decade, the future of electroluminescent quantum dot light-emitting devices (QDLEDs) is bright. State-of-the-art QDLEDs have achieved >30% EQE and a >2 000 000 h electroluminescence half-life for an initial luminance of 100 cd m−2, rivaling those of organic light-emitting devices. To date, most of the improvements in QDLED performance have been primarily achieved via advancements in QD synthesis and design that aim at reducing Auger recombination and improving the balance between electron and hole concentrations in the emissive QD layer. However, recent work is starting to reveal the critical role that other device layers, as well as interlayer interfaces, play in limiting QDLED stability. Degradation within the organic hole transport layer (HTL) and near the QD/HTL interface has recently been found to lead to the formation of nonradiative recombination centers that quench excitons in the emissive QD layer and contribute to QDLED failure over time. Looking forward, minimizing degradation in the charge transport layers will likely be crucial for the realization of highly stable QDLEDs and this perspective provides potential avenues to achieve these enhancements. In particular, tailoring the QD energy levels via material selection or interfacial dipoles may reduce charge carrier accumulation in the transport layers and replacing the organic HTL with an inorganic alternative may be an effective approach to circumvent the inherent susceptibility of organic semiconductors to exciton-induced degradation.
Flexible water molecule in C60: Intramolecular vibrational frequencies and translation-rotation eigenstates from fully coupled nine-dimensional quantum calculations with small basis sets
Authors: Felker Peter M. , Bačić Zlatko
Published: January 2020

We present a method for efficient calculation of intramolecular vibrational excitations of H2O inside C60, together with the low-energy intermolecular translation-rotation states within each intramolecular vibrational manifold. Apart from assuming rigid C60, this nine-dimensional (9D) quantum treatment is fully coupled. Following the recently introduced approach [P. M. Felker and Z. Bačić, J. Chem. Phys. 151, 024305 (2019)], the full 9D vibrational Hamiltonian of H2O@C60 is partitioned into two reduced-dimension Hamiltonians, a 6D one for the intermolecular vibrations and another in 3D for the intramolecular degrees of freedom, and a 9D remainder term. The two reduced-dimension Hamiltonians are diagonalized, and their eigenvectors are used to build up a product contracted basis in which the full vibrational Hamiltonian is diagonalized. The efficiency of this methodology derives from the insight of our earlier study referenced above that converged high-energy intramolecular vibrational excitations of weakly bound molecular complexes can be obtained from fully coupled quantum calculations where the full-dimensional product contracted basis includes only a small number of intermolecular vibrational eigenstates spanning the range of energies much below those of the intramolecular vibrational states of interest. In this study, the eigenstates included in the 6D intermolecular contacted basis extend to only 410 cm−1 above the ground state, which is much less than the H2O stretch and bend fundamentals, at ≈3700 and ≈1600 cm−1, respectively. The 9D calculations predict that the fundamentals of all three intramolecular modes, as well as the bend overtone, of the caged H2O are blueshifted relative to those of the gas-phase H2O, the two stretch modes much more so than the bend. Excitation of the bend mode affects the energies of the low-lying H2O rotational states significantly more than exciting either of the stretching modes. The center-of-mass translational fundamental is virtually unaffected by the excitation of any of the intramolecular vibrational modes. Further progress hinges on the experimental measurement of the vibrational frequency shifts in H2O@C60 and ab initio calculation of a high-quality 9D potential energy surface for this endohedral complex, neither of which is presently available.
Wildland fire emission factors in North America: synthesis of existing data, measurement needs and management applications
Authors: Prichard Susan J. , O'Neill Susan M. , Eagle Paige , Andreu Anne G. , Drye Brian , Dubowy Joel , Urbanski Shawn , Strand Tara M.
Published: January 2020

Field and laboratory emission factors (EFs) of wildland fire emissions for 276 known air pollutants sampled across Canada and the US were compiled. An online database, the Smoke Emissions Repository Application (SERA), was created to enable analysis and summaries of existing EFs to be used in smoke management and emissions inventories. We evaluated how EFs of select pollutants (CO, CO2, CH4, NOx, total particulate matter (PM), PM2.5 and SO2) are influenced by combustion phase, burn type and fuel type. Of the 12533 records in the database, over a third (n=5637) are represented by 23 air pollutants, most designated as US Environmental Protection Agency criteria air pollutants, greenhouse gases, hazardous air pollutants or known air toxins. Among all pollutants in the database, including the most common pollutants PM, CO, CO2 and CH4, records are unevenly distributed with a bias towards flaming combustion, prescribed burning and laboratory measurements. Across all EFs, records are most common for south-eastern and western conifer forests and western shrubland types. Based on identified data gaps, we offer recommendations for future studies, including targeting underrepresented air pollutants, smouldering combustion phases and improved source characterisation of wildland fire emissions.
Performances for upward mobility: How Dutch workfare programmes function as temporal spaces of imagination
Authors: Arts Josien
Published: January 2020

The gradual retreat of many governments from actively supporting secure labour relations and social security through welfare arrangements, and the related normalisation of precarious conditions, goes hand-in-hand with a promise of the attainability of ‘the good life’ through work. Workfare programmes are at the centre of this, as they are aimed at ‘improving’ welfare clients and their position in society through performing precarious work. Based on an ethnographic study of group workshops in three Dutch workfare programmes, this article shows how welfare clients are taught the promise of upward mobility through waged labour and are required to give ‘the right’ performances that might (in principle if, often, not in practice) potentially enable them to be successful on the post-Fordist labour market. I argue that these workshops function as temporal spaces of imagination in which adherence to the promise of upward mobility through paid work can best be understood as a form of post-Fordist affect, one that enacts, albeit temporarily, a resolution that is frequently lacking in real life.
Exocyst structural changes associated with activation of tethering downstream of Rho/Cdc42 GTPases
Authors: Rossi Guendalina , Lepore Dante , Kenner Lillian , Czuchra Alexander B. , Plooster Melissa , Frost Adam , Munson Mary , Brennwald Patrick
Published: January 2020

The exocyst complex plays a critical role in determining both temporal and spatial dynamics of exocytic vesicle tethering and fusion with the plasma membrane. However, the mechanism by which the exocyst functions and how it is regulated remain poorly understood. Here we describe a novel biochemical assay for the examination of exocyst function in vesicle tethering. Importantly, the assay is stimulated by gain-of-function mutations in the Exo70 component of the exocyst, selected for their ability to bypass Rho/Cdc42 activation in vivo. Single-particle electron microscopy and 3D reconstructions of negatively stained exocyst complexes reveal a structural change in the mutant exocyst that exposes a binding site for the v-SNARE. We demonstrate a v-SNARE requirement in our tethering assay and increased v-SNARE binding to exocyst gain-of-function complexes. Together, these data suggest an allosteric mechanism for activation involving a conformational change in one subunit of the complex, which is relayed through the complex to regulate its biochemical activity in vitro, as well as overall function in vivo.
Comparative analysis of the Coulomb barrier in heavy-ion collisions by the double-folding method
Authors: Ganiev O K , Nasirov A K
Published: January 2020

The double-folding formalism has been applied to calculate the nucleus-nucleus potential by the use of the effective nucleon-nucleon (Migdal) potential and the nuclear densities of the interacting nuclei presented as the Gaussian-type functions and polynomials. The Coulomb barrier heights obtained by this way and by different types of the proximity potentials have been compared. The deviations of the theoretical values of the Coulomb barrier from the values extracted from the experimental data are discussed. The capture cross section calculated for the reactions with the light projectiles is in good agreement with experimental values. The theoretical results obtained for the 16O+144Sm and 17O+144Sm reactions could reproduce a significant difference in the experimental results for these reaction, which is related with the extra neutron in 17O. The overestimation of the experimental data obtained from different sources by the curve of the theoretical results of the 40Ca+96Zr reactions is explained by the appearance of the slight hindrance to complete fusion, i.e the capture and fusion cross sections are not equal in this reaction.
Trivial band topology of ultra-thin rhombohedral Sb2Se3 grown on Bi2Se3
Authors: Matetskiy A V , Mararov V V , Kibirev I A , Zotov A V , Saranin A A
Published: January 2020

Thin films of rhombohedral Sb2Se3 with thicknesses from 1 to 5 quintuple layers (QL) were grown on Bi2Se3/Si(1 1 1) substrate. The electronic band structure of the grown films and the Sb2Se3/Bi2Se3 interface were studied using angle-resolved photoemission spectroscopy. It was found that while Sb2Se3 has an electronic band structure generally similar to that of Bi2Se3, there is no fingerprints of band inversion in it. Instead, the one-QL-thick Sb2Se3 films show direct band gap of about 80 meV. With growing film thickness, the Fermi level of the Sb2Se3 films gradually shifts by 200 meV for 5 QL-thick film revealing the band bending of the Sb2Se3/Bi2Se3 hetero-junction.
Magnetic-repulsion-coupled piezoelectric-film-based stretchable and flexible acoustic emission sensor
Authors: Feng Guo-Hua , Chiang Cheng-Yen
Published: January 2020

This paper presents a stretchable and flexible acoustic emission (AE) sensor composed of patterned upper, lower piezoelectric film foils, magnets and stereolithographic structures. The proposed device possesses the following novelties. The piezoelectric sensing structures with magnetic repulsion is effective for AE signal coupling. The lower piezoelectric serpentine-shaped AE detection structure with stretchable and flexible characteristics allows sensing various curved surfaces. Additionally, the contact force between the sensing target and AE sensor can be evaluated by monitoring the structural characteristic change of the upper piezoelectric structure of the AE sensor. The magnetic-repulsion-enhanced AE sensor exhibits a better bandwidth compared to that with only a lower AE sensing structure. Also, the fabricated sensor subjected to a sensing target force ranging from 4.98 to 14.85 mN resulting in a frequency change of the piezoelectric sensing beam of the upper foil from 20.073 to 20.135 kHz is verified. The developed AE sensor can open a new field for various applications. For instance, AE waves can be monitored without contacting the target (e.g. interfacing with air). The detection mechanism of AE waves by an action at a distance is successfully demonstrated.
Loading influence on the corrosion assessment during stress-induced martensite reorientation in nickel-titanium SMA
Authors: Mohajeri Mahdi , Case Raymundo , Haghgouyan Behrouz , Lagoudas Dimitris C , Castaneda Homero
Published: January 2020

The effect of stress-induced martensite reorientation on the corrosion behavior of a nickel-titanium (NiTi) shape memory alloy (SMA) was characterized by mechanical-electrochemical techniques. This martensite reorientation influenced the passive state of NiTi SMA. These passive to active state transitions could be sensed by the global interfacial electrochemical measurements, such as electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) and linear polarization resistance (LPR) methods. The increase in the loading when exposed to a corrosive environment resulted in the breakdown of the passive layer. A later repassivation stage was reached due to the formation rate becoming more dominant than the breakdown rate during loading conditions. The integration of the mechanical loading by tensile testing, strain distribution by digital image correlation (DIC) and electrochemical methods by OCP and EIS, characterized and detected the influence of the mechanical effect in the corrosion assessment and interfacial mechanisms.
Dynamic phase fluctuations in potential-driven Bose–Einstein condensate
Authors: Ma Decheng , Koval Vladimir , Jia Chenglong
Published: January 2020

We report on the dynamics of a Bose–Einstein condensate in one and two dimensions driven by the time-dependent harmonic trapping potential. Without the inter-particle interaction, the condensate exhibits the coherent behavior with the time-oscillating density distribution. When the inter-particle interaction is taken into consideration, the phase fluctuations, the multi-peak structure of the density distribution, and the coherence revival phenomenon, apart from the well-studied density oscillation behavior, can be observed in the condensate. Furthermore, it is demonstrated that due to the dimensional restriction these effects are more stable in the two and three-dimensional system, if compared to the one-dimensional case.
Effects of changes in land use on the diurnal temperature range: a long-term data analysis
Authors: Ueno Kazuki , Ohta Shunji
Published: January 2020

Air temperature is sensitive to changes in local land use. In this study, we investigated the effect of dam lake water on the air temperature based on open climate data. Lake Sayama (and its surroundings), located in Tokorozawa City, 30 km from Tokyo, Japan, was undertaken as the case study. This artificial lake was empty for three years for seismic reinforcement. To remove the effects of time-series changes in the air temperature, nearby observation stations where the air temperature difference did not change from that of Tokorozawa during the analysis period were selected. Analysis of data revealed that the minimum air temperature increased, and the maximum air temperature slightly decreased during the period when the dam reservoir was full throughout the year. Moreover, the reduction in the diurnal range of air temperatures was 1.78 °C in December and 0.46 °C in August. The effect of the lake on the air temperature reflected the size of the lake and the climatic zone. These results highlight the need for maintaining a network of meteorological observation stations, whose data can prove useful for identifying local climate changes due to land use.
Compliant bipolar electrostatic gripper using 3D-printed-layered elastic probes
Authors: Hemthavy Pasomphone , Kudo Kenta , Kawano Kento , Takahashi Kunio , Saito Shigeki
Published: January 2020

A 3D-printed-layered structure for forming the compliant bipolar electrostatic gripper is proposed. A prototype gripper module, which consists of an array of elastically deformable bipolar micro-probes, is fabricated using a conventional 3D printer. Experiments are conducted to examine the attractive force and the pick-and-place performance of the prototype. Experimental results show that the prototype module can generate the maximum attractive pressure of 87.1 Pa, which can pick and hold a piece of xerographic paper of 31.2 mg successfully. The effects of residual charges and the probe-tips flattening process on the attractive force are also discussed.
PamgeneAnalyzeR: open and reproducible pipeline for kinase profiling
Authors: Bekkar Amel , Nasrallah Anita , Guex Nicolas , Fajas Lluis , Xenarios Ioannis , Lopez-Mejia Isabel C
Published: January 2020

Protein phosphorylation––catalyzed by protein kinases–is the most common post-translational modification. It increases the functional diversity of the proteome and influences various aspects of normal physiology and can be altered in disease states. High throughput profiling of kinases is becoming an essential experimental approach to investigate their activity and this can be achieved using technologies such as PamChip® arrays provided by PamGene for kinase activity measurement. Here, we present ‘pamgeneAnalyzeR’, an R package developed as an alternative to the manual steps necessary to extract the data from PamChip® peptide microarrays images in a reproducible and robust manner. The extracted data can be directly used for downstream analysis.

Availability and implementation

PamgeneAnalyzeR is implemented in R and can be obtained from https://github.com/amelbek/pamgeneAnalyzeR.
A comprehensive in vivo and mathematic modeling-based kinetic characterization for aspirin-induced chemoprevention in colorectal cancer
Authors: Shimura Tadanobu , Toden Shusuke , Komarova Natalia L , Boland Crichard , Wodarz Dominik , Goel Ajay
Published: January 2020

Accumulating evidence suggests that aspirin has anti-tumorigenic properties in colorectal cancer (CRC). Herein, we undertook a comprehensive and systematic series of in vivo animal experiments followed by 3D-mathematical modeling to determine the kinetics of aspirin’s anti-cancer effects on CRC growth. In this study, CRC xenografts were generated using four CRC cell lines with and without PIK3CA mutations and microsatellite instability, and the animals were administered with various aspirin doses (0, 15, 50, and 100 mg/kg) for 2 weeks. Cell proliferation, apoptosis and protein expression were evaluated, followed by 3D-mathematical modeling analysis to estimate cellular division and death rates and their impact on aspirin-mediated changes on tumor growth. We observed that aspirin resulted in a dose-dependent decrease in the cell division rate, and a concomitant increase in the cell death rates in xenografts from all cell lines. Aspirin significantly inhibited cell proliferation as measured by Ki67 staining (P < 0.05–0.01). The negative effect of aspirin on the rate of tumor cell proliferation was more significant in xenograft tumors derived from PIK3CA mutant versus wild-type cells. A computational model of 3D-tumor growth suggests that the growth inhibitory effect of aspirin on the tumor growth kinetics is due to a reduction of tumor colony formation, and that this effect is sufficiently strong to be an important contributor to the reduction of CRC incidence in aspirin-treated patients. In conclusion, we provide a detailed kinetics of aspirin-mediated inhibition of tumor cell proliferation, which support the epidemiological data for the observed protective effect of aspirin in CRC patients.
Synaptic Zinc Enhances Inhibition Mediated by Somatostatin, but not Parvalbumin, Cells in Mouse Auditory Cortex
Authors: Kouvaros Stylianos , Kumar Manoj , Tzounopoulos Thanos
Published: January 2020

Cortical inhibition is essential for brain activity and behavior. Yet, the mechanisms that modulate cortical inhibition and their impact on sensory processing remain less understood. Synaptically released zinc, a neuromodulator released by cortical glutamatergic synaptic vesicles, has emerged as a powerful modulator of sensory processing and behavior. Despite the puzzling finding that the vesicular zinc transporter (ZnT3) mRNA is expressed in cortical inhibitory interneurons, the actions of synaptic zinc in cortical inhibitory neurotransmission remain unknown. Using in vitro electrophysiology and optogenetics in mouse brain slices containing the layer 2/3 (L2/3) of auditory cortex, we discovered that synaptic zinc increases the quantal size of inhibitory GABAergic neurotransmission mediated by somatostatin (SOM)- but not parvalbumin (PV)-expressing neurons. Using two-photon imaging in awake mice, we showed that synaptic zinc is required for the effects of SOM- but not PV-mediated inhibition on frequency tuning of principal neurons. Thus, cell-specific zinc modulation of cortical inhibition regulates frequency tuning.
Prevalence and Incidence of Human Papillomavirus Infection in Men Having Sex With Men Enrolled in a Pre-exposure Prophylaxis Study: A Sub-study of the Agence Nationale de Recherches sur le SIDA et les Hépatites Virales “Intervention Préventive de l’Exposition aux Risques avec et pour les hommes Gays” Trial
Authors: Cotte Laurent , Veyer David , Charreau Isabelle , Péré Hélène , Cua Eric , Carette Diane , Chas Julie , Capitant Catherine , Chidiac Christian , Fléjou Jean-François , Fouéré Sébastien , Heard Isabelle , Meyer Laurence , Puech Julien , Tremblay Cécile , Delaugerre Constance , Molina Jean-Michel
Published: January 2020

Background

Human papillomavirus (HPV) infection is more frequent in men having sex with men (MSM) who are living with human immunodeficiency virus (HIV) than in MSM without HIV. There are currently no data regarding HPV infections in preexposure prophylaxis (PrEP)-using MSM.

Methods

MSM living without HIV who were enrolled in the Agence Nationale de Recherches sur le SIDA et les Hépatites Virales "Intervention Préventive de l'Exposition aux Risques avec et pour les hommes Gays" PrEP study were prospectively enrolled. Anal, penile, and oral samples were collected at baseline and every 6 months for HPV detection and genotyping. Anal swabs for cytology were obtained at baseline and at 24 months.

Results

We enrolled 162 participants. The prevalences of any HPV genotypes at baseline were 92%, 32%, and 12% at the anal, penile, and oral sites, respectively. High-risk (HR) HPV genotypes were observed in 84%, 25%, and 10% of anal, penile, and oral baseline samples, respectively. Nonavalent HPV vaccine genotypes were observed in 77%, 22%, and 6% of anal, penile, and oral baseline samples, respectively. Multiple infections were observed in 76%, 17%, and 3% of cases at the anal, penile, and oral sites, respectively. The most frequent HR genotypes were HPV 53, 51, and 16 in anal samples; HPV 33, 39, and 73 in penile samples; and HPV 66 in oral samples. The incidence of any HPV genotype at the anal site was 86.2/1000 person-months and the incidence of HR-HPV genotypes was 72.3/1000 person-months. The baseline cytology was normal in 32% of cases and was classified as atypical squamous cells of undetermined significance, low-grade squamous intra-epithelial lesion, high-grade squamous intra-epithelial lesion (HSIL), and atypical squamous cells that cannot exclude HSIL in 23%, 40%, 5%, and 1% of cases, respectively.

Conclusions

PrEP users have a similar risk of HPV infection as MSM living with HIV and the risk is much higher than that previously reported in MSM living without HIV.
Hepatitis B Virus RNA as Early Predictor for Response to Pegylated Interferon Alpha in HBeAg-Negative Chronic Hepatitis B
Authors: Farag Mina S , van Campenhout Margo J H , Pfefferkorn Maria , Fischer Janett , Deichsel Danilo , Boonstra André , van Vuuren Anneke J , Ferenci Peter , Feld Jordan J , Berg Thomas , Hansen Bettina E , van Bömmel Florian , Janssen Harry L A
Published: January 2020

Background

Hepatitis B virus RNA (HBV-RNA) is a novel serum biomarker that correlates with transcription of intrahepatic covalently closed circular (cccDNA), which is an important target for pegylated interferon (PEG-IFN) and novel therapies for functional cure. We studied HBV-RNA kinetics following PEG-IFN treatment and its potential role as a predictor to response in HBeAg-negative chronic hepatitis B (CHB) patients.

Methods

HBV-RNA levels were measured in 133 HBeAg-negative CHB patients treated in an international randomized controlled trial (PARC study). Patients received PEG-IFN α-2a for 48 weeks. HBV-RNA was measured from baseline through week 144. Response was defined as HBV-DNA <2000 IU/mL and ALT normalization at week 72. Kinetics of HBV-RNA were compared with HBV-DNA, HBsAg, and HBcrAg.

Results

Mean HBV-RNA at baseline was 4.4 (standard deviation [SD] 1.2) log10 c/mL. At week 12, HBV-RNA declined by −1.6 (1.1) log10 c/mL. HBV-RNA showed a greater decline in responders compared to nonresponders early at week 12 (−2.0 [1.2] vs −1.5 [1.1] log10 c/mL, P = .04). HBV-RNA level above 1700 c/mL (3.2 log10 c/mL) had a negative predictive value of 91% at week 12 and 93% at week 24 (P = .01) for response. Overall, HBV-RNA showed a stronger correlation with HBV-DNA and HBcrAg (.82 and .80, P < .001) and a weak correlation with HBsAg (.25). At week 12, HBV-RNA was significantly lower among patients with lower HBsAg (<100 IU/mL) or HBsAg loss at week 144.

Conclusions

During PEG-IFN treatment for HBeAg-negative CHB, HBV-RNA showed a fast and significant decline that correlates with treatment response and HBsAg loss at long-term follow-up.

Clinical Trials Registration

NCT00114361
Kt/V: achievement, predictors and relationship to mortality in hemodialysis patients in the Gulf Cooperation Council countries: results from DOPPS (2012–18)
Authors: AlSahow Ali , Muenz Daniel , Al-Ghonaim Mohammed A , Al Salmi Issa , Hassan Mohamed , Al Aradi Ali H , Hamad Abdullah , Al-Ghamdi Saeed M G , Shaheen Faissal A M , Alyousef Anas , Bieber Brian , Robinson Bruce M , Pisoni Ronald L
Published: January 2020

Background

Dialysis adequacy, as measured by single pool Kt/V, is an important parameter for assessing hemodialysis (HD) patients’ health. Guidelines have recommended Kt/V of 1.2 as the minimum dose for thrice-weekly HD. We describe Kt/V achievement, its predictors and its relationship with mortality in the Gulf Cooperation Council (GCC) (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates).

Methods

We analyzed data (2012–18) from the prospective cohort Dialysis Outcomes and Practice Patterns Study for 1544 GCC patients ≥18 years old and on dialysis >180 days.

Results

Thirty-four percent of GCC HD patients had low Kt/V (<1.2) versus 5%–17% in Canada, Europe, Japan and the USA. Across the GCC countries, low Kt/V prevalence ranged from 10% to 54%. In multivariable logistic regression, low Kt/V was more common (P < 0.05) with larger body weight and height, being male, shorter treatment time (TT), lower blood flow rate (BFR), greater comorbidity burden and using HD versus hemodiafiltration. In adjusted Cox models, low Kt/V was strongly related to higher mortality in women [hazard ratio (HR) = 1.91, 95% confidence interval (CI) 1.09–3.34] but not in men (HR = 1.16, 95% CI 0.70–1.92). Low BFR (<350 mL/min) and TT (<4 h) were common; 41% of low Kt/V cases were attributable to low BFR or TT (52% for women and 36% for men).

Conclusion

Relatively large proportions of GCC HD patients have low Kt/V. Increasing BFR to ≥350 mL/min and TT to ≥4 h thrice weekly will reduce low Kt/V prevalence and may improve survival in GCC HD patients—particularly among women.
The Organizational Field of Blood Collection: A Multilevel Analysis of Organizational Determinants of Blood Donation in Europe
Authors: Gorleer Sam , Bracke Piet , Hustinx Lesley
Published: January 2020

Maintaining an adequate blood supply for transfusion poses a pressing challenge to society. We argue that this challenge has not been adequately addressed in previous research. Building upon Healy’s seminal work on ‘blood-collection regimes’ and the subsequent shift towards a field-level approach that broadens the analytical focus beyond the dyadic relationship between donors and organizations, we embed the act of blood donation within the organizational field in which blood establishments operate. We assume that varying modes of governance shape the organizational practices of donor recruitment and blood collection. Our analysis is based on Eurobarometer data from 2014 (number of countries = 28; number of individuals = 19,363). The results identify considerable variance in donation rates according to field characteristics in terms of hierarchical centralization and competitiveness. Decentralized systems without competition perform worst in terms of the recruitment of (first-time) blood donors. Competitive systems in which several different bodies share responsibility for the provision of blood to patients yield the highest donation rates.
Termination of persistent atrial fibrillation by ablating sites that control large atrial areas
Authors: Bhatia Neal K , Rogers Albert J , Krummen David E , Hossainy Samir , Sauer William , Miller John M , Alhusseini Mahmood I , Peszek Adam , Armenia Erin , Baykaner Tina , Brachmann Johannes , Turakhia Mintu P , Clopton Paul , Wang Paul J , Rappel Wouter-Jan , Narayan Sanjiv M
Published: January 2020

Aims 

Persistent atrial fibrillation (AF) has been explained by multiple mechanisms which, while they conflict, all agree that more disorganized AF is more difficult to treat than organized AF. We hypothesized that persistent AF consists of interacting organized areas which may enlarge, shrink or coalesce, and that patients whose AF areas enlarge by ablation are more likely to respond to therapy.

Methods and results 

We mapped vectorial propagation in persistent AF using wavefront fields (WFF), constructed from raw unipolar electrograms at 64-pole basket catheters, during ablation until termination (Group 1, N = 20 patients) or cardioversion (Group 2, N = 20 patients). Wavefront field mapping of patients (age 61.1 ± 13.2 years, left atrium 47.1 ± 6.9 mm) at baseline showed 4.6 ± 1.0 organized areas, each separated by disorganization. Ablation of sites that led to termination controlled larger organized area than competing sites (44.1 ± 11.1% vs. 22.4 ± 7.0%, P < 0.001). In Group 1, ablation progressively enlarged unablated areas (rising from 32.2 ± 15.7% to 44.1 ± 11.1% of mapped atrium, P < 0.0001). In Group 2, organized areas did not enlarge but contracted during ablation (23.6 ± 6.3% to 15.2 ± 5.6%, P < 0.0001).

Conclusion 

Mapping wavefront vectors in persistent AF revealed competing organized areas. Ablation that progressively enlarged remaining areas was acutely successful, and sites where ablation terminated AF were surrounded by large organized areas. Patients in whom large organized areas did not emerge during ablation did not exhibit AF termination. Further studies should define how fibrillatory activity is organized within such areas and whether this approach can guide ablation.
Barriers and facilitators to GP–patient communication about emotional concerns in UK primary care: a systematic review
Authors: Parker Daisy , Byng Richard , Dickens Chris , Kinsey Debbie , McCabe Rose
Published: January 2020

Background

In the UK, general practitioners (GPs) are the most commonly used providers of care for emotional concerns.

Objective

To update and synthesize literature on barriers and facilitators to GP–patient communication about emotional concerns in UK primary care.

Design

Systematic review and qualitative synthesis.

Method

We conducted a systematic search on MEDLINE (OvidSP), PsycInfo and EMBASE, supplemented by citation chasing. Eligible papers focused on how GPs and adult patients in the UK communicated about emotional concerns. Results were synthesized using thematic analysis.

Results

Across 30 studies involving 342 GPs and 720 patients, four themes relating to barriers were: (i) emotional concerns are difficult to disclose; (ii) tension between understanding emotional concerns as a medical condition or arising from social stressors; (iii) unspoken assumptions about agency resulting in too little or too much involvement in decisions and (iv) providing limited care driven by little time. Three facilitative themes were: (v) a human connection improves identification of emotional concerns and is therapeutic; (vi) exploring, explaining and negotiating a shared understanding or guiding patients towards new understandings and (vii) upfront information provision and involvement manages expectations about recovery and improves engagement in treatment.

Conclusion

The findings suggest that treatment guidelines should acknowledge: the therapeutic value of a positive GP–patient relationship; that diagnosis is a two-way negotiated process rather than an activity strictly in the doctor’s domain of expertise; and the value of exploring and shaping new understandings about patients’ emotional concerns and their management.
SPECC1L regulates palate development downstream of IRF6
Authors: Hall Everett G , Wenger Luke W , Wilson Nathan R , Undurty-Akella Sraavya S , Standley Jennifer , Augustine-Akpan Eno-Abasi , Kousa Youssef A , Acevedo Diana S , Goering Jeremy P , Pitstick Lenore , Natsume Nagato , Paroya Shahnawaz M , Busch Tamara D , Ito Masaaki , Mori Akihiro , Imura Hideto , Schultz-Rogers Laura E , Klee Eric W , Babovic-Vuksanovic Dusica , Kroc Sarah A , Adeyemo Wasiu L , Eshete Mekonen A , Bjork Bryan C , Suzuki Satoshi , Murray Jeffrey C , Schutte Brian C , Butali Azeez , Saadi Irfan
Published: January 2020

SPECC1L mutations have been identified in patients with rare atypical orofacial clefts and with syndromic cleft lip and/or palate (CL/P). These mutations cluster in the second coiled-coil and calponin homology domains of SPECC1L and severely affect the ability of SPECC1L to associate with microtubules. We previously showed that gene-trap knockout of Specc1l in mouse results in early embryonic lethality. We now present a truncation mutant mouse allele, Specc1lΔC510, that results in perinatal lethality. Specc1lΔC510/ΔC510 homozygotes showed abnormal palate rugae but did not show cleft palate. However, when crossed with a gene-trap allele, Specc1lcGT/ΔC510 compound heterozygotes showed a palate elevation delay with incompletely penetrant cleft palate. Specc1lcGT/ΔC510 embryos exhibit transient oral epithelial adhesions at E13.5, which may delay shelf elevation. Consistent with oral adhesions, we show periderm layer abnormalities, including ectopic apical expression of adherens junction markers, similar to Irf6 hypomorphic mutants and Arhgap29 heterozygotes. Indeed, SPECC1L expression is drastically reduced in Irf6 mutant palatal shelves. Finally, we wanted to determine if SPECC1L deficiency also contributed to non-syndromic (ns) CL/P. We sequenced 62 Caucasian, 89 Filipino, 90 Ethiopian, 90 Nigerian and 95 Japanese patients with nsCL/P and identified three rare coding variants (p.Ala86Thr, p.Met91Iso and p.Arg546Gln) in six individuals. These variants reside outside of SPECC1L coiled-coil domains and result in milder functional defects than variants associated with syndromic clefting. Together, our data indicate that palate elevation is sensitive to deficiency of SPECC1L dosage and function and that SPECC1L cytoskeletal protein functions downstream of IRF6 in palatogenesis.