bluuebunny/crossref_metadata_2025 huggingface dataset:
3D Evaluation of the Relationship between Different Vertical Growth Patterns and Cranial Base Angulations
Authors: Ugurlu Mehmet , Oksayan Rıdvan , Bayrakdar Ibrahim Sevki , Kahraman Fatih , Dagsuyu Ilhan Metin , Aydın Mehmet , Orhan Kaan
Published: August 2020

Objective This study aimed to compare cranial base angulations in subjects with high-angle, low-angle, and normal-angle vertical growth patterns using cone beam computed tomography (CBCT).

Design This study is a retrospective clinical research.

Settings This study was carried out at the Dentistry Faculty of Eskisehir Osmangazi University.

Participants According to skeletal vertical face growth patterns, 78 subjects (48 females and 30 males, average age: 13.19 ± 1.73 years) were divided equally into three groups: high angle, low angle, and normal angle groups.

Main Outcome Measures Cephalometric images were derived from CBCT, and patients were classified according to the SN-GoGn angle (sella-nasion, gonion gnathion angle). Sagittal, axial, and coronal cranial base angulations were measured in three-dimensional (3D) CBCT images. Data were analyzed using the Kolmogorov–Smirnov normality, Kruskal–Wallis, and Mann-Whitney U statistical tests.

Results There were statistically significant differences between the low-angle and high-angle groups according to sagittal cranial base angulation parameters (p = 0.01). Conversely, there were no statistically significant differences between vertical facial growth patterns according to coronal and axial cranial angle variables (p > 0.05).

Conclusion According to the study results, there were no effects of cranial base angulations in two planes (coronal and axial) on different vertical skeletal growth patterns. In the sagittal cranial base angulation parameter, the high-angle group showed greater angulation values than the low-angle group. CBCT may be helpful for evaluating, diagnosing, and predicting 3D cranial base differences.
Multifactorial Posterior Reversible Encephalopathy Syndrome in Children: Clinical, Laboratory, and Neuroimaging Findings
Authors: Morana Giovanni , Bagnasco Francesca , Leoni Massimiliano , Pasquini Luca , Gueli Ilaria , Tortora Domenico , Severino Mariasavina , Giardino Stefano , Pierri Filomena , Micalizzi Concetta , Verrina Enrico , Ravelli Angelo , Mancardi Maria Margherita , Rossi Andrea , Faraci Maura
Published: August 2020

The aim of this study was to investigate the association of neuroimaging, clinical, and laboratory findings in children with different underlying diseases who developed posterior reversible encephalopathy syndrome (PRES). All consecutive pediatric patients referred to our institute between 2000 and 2017 were retrospectively evaluated for newly diagnosed PRES. Clinical data, medical history, and therapies administered at the time of PRES and laboratory findings were reviewed as the magnetic resonance imaging (MRI) obtained at PRES presentation and during follow-up. Statistics included Mann–Whitney U, Chi-square, and Fisher's exact tests. A total of 39 pediatric patients (25 males, median age = 8.8 years) with a confirmed diagnosis of PRES were included. The patients were divided into four groups based on the underlying disease: (1) patients with hemato-oncological diseases not transplanted (n = 15, 38.5%), (2) who underwent hematopoietic stem cell transplantation (HSCT; n = 12, 30.8%), (3) affected by renal (n = 8, 20.5%), and (4) by autoimmune diseases (n = 4, 10.2%). Hemato-oncological patients and those undergoing HSCT presented a higher incidence of involvement of deep gray matter structures and hemorrhagic lesions when compared with patients with renal and autoimmune disorders (p = 0.036 and p = 0.036, respectively). No differences emerged among different groups of patients regarding presenting PRES symptoms, arterial blood pressure, laboratory findings, and extent of MRI abnormalities and these parameters did not show association with outcome.

In conclusion, in pediatric patients with different diseases who develop PRES, involvement of deep gray matter structures and hemorrhagic lesions are more common in hemato-oncological patients and those undergoing HSCT. Clinical and radiologic outcome is favorable independently of clinical data and extent of MRI abnormalities.
Blood Markers of Portal Hypertension Are Associated with Blood Loss and Transfusion Requirements during Orthotopic Liver Transplantation
Authors: Arshad Freeha , Lisman Ton , Porte Robert J.
Published: August 2020

There is increasing evidence that portal hypertension plays a major role in bleeding risk during orthotopic liver transplantation (OLT). We investigated the association between preoperative blood levels of von Willebrand factor (VWF) and soluble CD163 (sCD163), which are established markers of portal hypertension, and blood loss and transfusion requirements during OLT. We measured levels of VWF and sCD163 in preoperative serum samples of 168 adult patients undergoing a primary OLT between 1998 and 2012. Preoperative levels of VWF and sCD163 correlated with the model of end-stage liver disease (MELD) score (r = 0.414, p < 0.001 and r = 0.382, p < 0.001, respectively). Patients with high VWF or sCD163 levels (VWF and sCD163 levels above the median) had a substantially increased risk of needing red blood cell transfusion compared with patients with low VWF or sCD163 levels (VWF and sCD163 levels below the median) (odds ratio 3.5 [95% confidence interval, CI 1.7–7.0] and 2.3 [95% CI 1.1–4.5], respectively). Blood loss was highest in patients with both high VWF or sCD163 levels and a high preoperative international normalized ratio. Elevated blood levels of markers of portal hypertension are associated with increased blood loss and transfusion requirements during OLT and support the notion that portal hypertension is an important contributor to perioperative blood loss.
Patient Satisfaction following Structural versus Preservation Rhinoplasty: A Systematic Review
Authors: Levin Marc , Ziai Hedyeh , Roskies Michael
Published: August 2020

Recently, dorsal preservation rhinoplasty has been gained acceptance among facial plastic surgeons. Despite this, there is limited literature on patient satisfaction following preservation rhinoplasty. This systematic review aims to evaluate all studies quantifying patient satisfaction and to compare results between structural and dorsal preservation rhinoplasty. OVID Medline, EMBASE, and PubMed databases were searched. All studies from the years 2010 to 2020 evaluating satisfaction in patients receiving either structural or dorsal preservation rhinoplasty were included. Data regarding study demographics as well as patient satisfaction results were extracted from included studies. Descriptive results and analysis were calculated. A total of 2,172 articles were initially identified, of which 29 articles were included in the final analysis. Of the 29 articles, 25 were focused on structural rhinoplasty and 4 were focused on preservation rhinoplasty. Of the 25 structural rhinoplasty articles, 17 used the Rhinoplasty Outcome Evaluation (ROE) questionnaire to evaluate patient satisfaction and 5 used the FACE-Q scale. Among the 25 structural rhinoplasty studies, 14 (56%) reported statistically significant improvements in patient satisfaction evaluation scores after rhinoplasty. Among the four preservation rhinoplasty studies, one (25%) study reported significant improvements in satisfaction scores after rhinoplasty. Despite this, most studies included a statement that satisfaction improved in patients following rhinoplasty. Literature in this review supports both structural and preservation rhinoplasty, resulting in high satisfactory results for patients following surgery. More research must be conducted to further quantify satisfaction following preservation rhinoplasty and prospectively compare satisfaction between the two rhinoplasty techniques.
Extra Pancreatic Necrotic Volume: Can It Prognosticate Acute Necrotising Pancreatitis— A Prospective Study
Authors: Anandan Rinoy Ram , Patil Santosh , Renganathan Rupa , Varatharajaperumal Rajesh Kumar , Ramasamy Rajkumar , Arunachalam Venkatesh Kasi
Published: August 2020

Background Acute necrotizing pancreatitis (ANP) is associated with higher mortality and morbidity. We need a method which is accurate in predicting the prognosis, and when applied early in the disease process, can help in closer monitoring and early initiation of treatment for at-risk patients.

Objectives The aim of this prospective study was to assess the extra pancreatic necrosis (EPN) volume in patients with ANP and compare it with outcome variables such as organ failure, death and need for intervention as well as to compare the predictive power of EPN volume with modified CT severity index (CTSI).

Materials and Methods The study had 48 patients with clinical diagnosis of acute pancreatitis, who underwent Contrast enhanced CT (CECT) between 3–6 days of onset. In all these patients, EPN volume (in cubic centimetre) and modified CTSI score were calculated and compared with the patient outcome parameters such as duration of hospital/ICU stay, need for percutaneous/surgical intervention, evidence of infection and organ failure. The results were compared with assess the predictive power of EPN volume.

Statistical analysis The analysis was done in SPSS version 16.0 for windows. Pearson Correlation was used to assess the significant relationship between selected objective variables.

Results EPN volume (>/= to 360 cc) had a statistically significant correlation with outcome parameters as well as in predicting overall organ failure. In our study, Modified CTSI had no significant correlation with the above mentioned factors.

Conclusions The volume of EPN calculated between 3rd and 6th day of onset of symptoms showed a significant correlation with the outcome in patients with ANP.
On a quantum Hamiltonian in a unitary magnetic field with axisymmetric potential
Authors: Geniet Paul
Published: August 2020

We study a magnetic Schrödinger Hamiltonian, with axisymmetric potential in any dimension. The associated magnetic field is unitary and non-constant. The problem reduces to a 1D family of singular Sturm–Liouville operators on the half-line indexed by a quantum number. We study the associated band functions. They have finite limits that are the Landau levels. These limits play the role of thresholds in the spectrum of the Hamiltonian. We provide an asymptotic expansion of the band functions at infinity. Each Landau level concerns an infinity of band functions, and each energy level is intersected by an infinity of band functions. We show that among the band functions that intersect a fixed energy level, the derivative can be arbitrary small. We apply this result to prove that even if they are localized in energy away from the thresholds, quantum states possess a bulk component. A similar result is also true in classical mechanics.
Dismantling complex networks based on the principal eigenvalue of the adjacency matrix
Authors: Zhou Mingyang , Tan Juntao , Liao Hao , Wang Ziming , Mao Rui
Published: August 2020

The connectivity of complex networks is usually determined by a small fraction of key nodes. Earlier works successfully identify an influential single node, yet have some problems for the case of multiple ones. In this paper, based on the matrix spectral theory, we propose the collective influence of multiple nodes. An interesting finding is that some traditionally influential nodes have strong internal coupling interactions that reduce their collective influence. We then propose a greedy algorithm to dismantle complex networks by optimizing the collective influence of multiple nodes. Experimental results show that our proposed method outperforms the state of the art methods in terms of the principal eigenvalue and the giant component of the remaining networks.
Multispectral and low-filling-factor superconducting nanowire single photon detector with high absorption efficiency
Authors: Li Dezhi , Liu Xiangyuan , Jiao Rongzhen
Published: August 2020

We propose a superconducting nanowire single photon detector (SNSPD) that can work efficiently at two target wavelengths and has a significant improvement in the counting rate due to the low-filling-factor nanowires in the silicon slots and the silver reflector. Numerical simulations show that the absorption efficiency can be over 90% at a single wavelength, whether the incident light wavelength is 1550 nm or 1064 nm, and over 80% when the SNSPD is designed to work at both wavelengths. In addition, the reset time is about 24% of the conventional SNSPDs. Our work presents a design for fabricating faster, larger-area, and multispectral SNSPDs with a high efficiency, which can be applied in applications such as quantum optics communication and multiwavelength sensing.
Reaction-field model for the dielectric response of mixtures
Authors: Bakker Huib J.
Published: August 2020

We present a new effective medium theory for the dielectric response of mixtures of molecules with molecular polarizability and a permanent dipole moment. This model includes the interaction of each local dipole moment with the dipolar reaction fields of neighboring dipolar molecules. This interaction leads to an enhancement of the dielectric response of the mixture and constitutes an alternative method to describe the correlated motion of dipoles in liquids compared to the models of Fröhlich and Kirkwood. The model requires as input parameters the volume fractions of the components contained in the mixture and the dielectric parameters of the pure components. The results of the model are compared with experimental data and with the results of previous effective-medium theories.
Suppression of current source noise with an atomic magnetometer
Authors: Shen Liang , Zhang Rui , Wu Teng , Peng Xiang , Yu Song , Chen Jingbiao , Guo Hong
Published: August 2020

This paper introduces a method for using an atomic magnetometer to suppress current source noise. In this method, the current noise is (i) suppressed with a lamp-pumped cesium atomic magnetometer and (ii) measured with a higher-sensitivity laser-pumped cesium atomic magnetometer. The current noise is compared before and after noise suppression at an output current of 50 mA, and the noise-suppression ratio is ∼27 dB. The noise-suppression performance can be enhanced by improving the sensitivity of the atomic magnetometer and the ability to restrain the ambient magnetic noise. This method has practical applications in metrology and fundamental physics research.
Validated two-dimensional modeling of short carbon arcs: Anode and cathode spots
Authors: Chen J. , Khrabry A. , Kaganovich I. D. , Khodak A. , Vekselman V. , Li H.-P.
Published: August 2020

In order to study the properties of short carbon arcs, a self-consistent model was implemented into a CFD code ANSYS-CFX. The model treats the transport of heat and electric current in the plasma and electrodes in a coupled manner and accounts for gas convection in the chamber. Multiple surface processes at the electrodes are modeled, including the formation of space-charge limited sheaths, ablation and deposition of carbon, and emission and absorption of radiation and electrons. The simulations show that the arc is constricted near the cathode and anode front surfaces, leading to the formation of electrode spots. The cathode spot is a well-known phenomenon, and mechanisms of its formation were reported elsewhere. However, the anode spot formation mechanism discovered in this work was not previously reported. We conclude that the spot formation is not related to plasma instability, as commonly believed in the case of constricted discharge columns, but rather occurs due to the highly nonlinear nature of heat balance in the anode. We additionally demonstrate this property with a reduced anode heat transfer model. We also show that the spot size increases with the arc current. This anode spot behavior was also confirmed in our experiments. Due to the anode spot formation, a large gradient of carbon gas density occurs near the anode, which drives a portion of the ablated carbon back to the anode at its periphery. This can consequently reduce the total ablation rate. Simulation results also show that the arc can reach the local chemical equilibrium state in the column region, while the local thermal equilibrium state is not typically achieved for experimental conditions. It shows that it is important to account for different electron and gas temperatures in the modeling of short carbon arcs.
An 18.3 MJ charging and discharging pulsed power supply system for the Space Plasma Environment Research Facility (SPERF). I. The overall design
Authors: Mao Aohua , Ma Xun , E Peng , Guan Jian , Ling Wenbin , Li Liyi , Li Hongtao
Published: August 2020

The Space Plasma Environment Research Facility (SPERF) is a new ground-based experimental device for fundamental research studies on space plasma currently under construction at Harbin Institute of Technology in China. Scientific objectives of the SPERF include studying the asymmetric reconnection dynamics relevant to the interaction between the interplanetary and magnetospheric plasmas, reproducing the inner magnetosphere to simulate the processes of trapping, acceleration, and transport of energetic charged particles restrained in a dipole magnetic field configuration, and revealing the physical mechanism of the dipolarization front in the magnetotail. The device comprises a vacuum chamber, 11 coils consisting of 18 groups of sub-coils that are independently programmablely energized, and the plasma source system to provide the magnetic field and the plasma required by the physical experiments. Thus, each of these 18 groups of sub-coils requires a separate pulsed power supply; furthermore, the 18 pulsed power supplies constitute the pulsed power supply system of the SPERF of which the total storage energy is up to 18.3 MJ, and the technical challenges have to be overcome. The power supply energizing a dipole field coil (labeled OJC coil) wired by the copper wire to provide a dipole magnetic field is the most energetic power supply (labeled OJC power supply) with a 2.42 MJ, 16.8 mF capacitor bank charged to 20 kV. The OJC power supply delivers a current with a peak of 18 kA for a rise time of ∼26.69 ms, and the duration of the current is not less than 95% of the peak over 10 ms to the OJC coil. Meanwhile, the most challenging power supply is the power supply labeled poloidal field power supply with a 5.04 mF capacitor bank charged to 20 kV, which provides the excitation current for the load coil set with the current not less than 360 kA at the typical time of 0.11 ms to produce the sufficient growth of the magnetic field that the experiments need. In this paper, the overall design of the pulsed power supply system, the design concept of the modularization, and the principle selection basis of the key components are presented. The technical details of each power supply will be demonstrated in the future.
Recent progress on particle acceleration and reconnection physics during magnetic reconnection in the magnetically-dominated relativistic regime
Authors: Guo Fan , Liu Yi-Hsin , Li Xiaocan , Li Hui , Daughton William , Kilian Patrick
Published: August 2020

Magnetic reconnection in strongly magnetized astrophysical plasma environments is believed to be the primary process for fast energy release and particle energization. Currently, there is strong interest in relativistic magnetic reconnection in that it may provide a new explanation for high-energy particle acceleration and radiation in strongly magnetized astrophysical systems. We review recent advances in particle acceleration and reconnection physics in the magnetically dominated regime. Much discussion is focused on the physics of particle acceleration and power-law formation as well as the reconnection rate problem. In addition, we provide an outlook for studying reconnection acceleration mechanisms and kinetic physics in the next step.
Water adlayers on noble metal surfaces: Insights from energy decomposition analysis
Authors: Clabaut Paul , Staub Ruben , Galiana Joachim , Antonetti Elise , Steinmann Stephan N.
Published: August 2020

Water molecules adsorbed on noble metal surfaces are of fundamental interest in surface science, in heterogeneous catalysis, and as a model for the metal/water interface. Herein, we analyze 28 water structures adsorbed on five noble metal surfaces (Cu, Ag, Au, Pd, and Pt) via density functional theory and energy decomposition analysis based on the block localized wave function technique. Structures, ranging from monomers to ice adlayers, reveal that the charge transfer from water to the surface is nearly independent from the charge transfer between the water molecules, while the polarization energies are cooperative. Dense water–water networks with small surface dipoles, such as the 39×39 unit cell [experimentally observed on Pt(111)], are favored compared to the highly ordered and popular Hup and Hdown phases. The second main result of our study is that the many-body interactions, which stabilize the water assemblies on the metal surfaces, are dominated by the polarization energies, with the charge transfer scaling with the polarization energies. Hence, if an empirical model could be found that reproduces the polarization energies, the charge transfer could be predicted as well, opening exciting perspectives for force field development.
Improved reference system for the corrected rigid spheres equation of state model
Authors: Cowen B. J. , Carpenter J. H.
Published: August 2020

The Corrected Rigid Spheres (CRIS) equation of state (EOS) model [Kerley, J. Chem. Phys. 73, 469 (1980); 73, 478 (1980); 73, 487 (1980)], developed from fluid perturbation theory using a hard sphere reference system, has been successfully used to calculate the EOS of many materials, including gases and metals. The radial distribution function (RDF) plays a pivotal role in choosing the sphere diameter, through a variational principle, as well as the thermodynamic response. Despite its success, the CRIS model has some shortcomings in that it predicts too large a temperature for liquid-vapor critical points, can break down at large compression, and is computationally expensive. We first demonstrate that an improved analytic representation of the hard sphere RDF does not alleviate these issues. Relaxing the strict adherence of the RDF to hard spheres allows an accurate fit to the isotherms and vapor dome of the Lennard-Jones fluid using an arbitrary reference system. The second order correction is eliminated, limiting the breakdown at large compression and significantly reducing the computation cost. The transferability of the new model to real systems is demonstrated on argon, with an improved vapor dome compared to the original CRIS model.
Slack reactants: A state-space truncation framework to estimate quantitative behavior of the chemical master equation
Authors: Kim Jinsu , Dark Jason , Enciso German , Sindi Suzanne
Published: August 2020

State space truncation methods are widely used to approximate solutions of the chemical master equation. While most methods of this kind focus on truncating the state space directly, in this work, we propose modifying the underlying chemical reaction network by introducing slack reactants that indirectly truncate the state space. More specifically, slack reactants introduce an expanded chemical reaction network and impose a truncation scheme based on desired mass conservation laws. This network structure also allows us to prove inheritance of special properties of the original model, such as irreducibility and complex balancing. We use the network structure imposed by slack reactants to prove the convergence of the stationary distribution and first arrival times. We then provide examples comparing our method with the stationary finite state projection and finite buffer methods. Our slack reactant system appears to be more robust than some competing methods with respect to calculating first arrival times.
Configurable activation function realized by non-linear memristor for neural network
Authors: Li Kun , Sun Yi , Wang Wei , Zhu Xi , Song Bing , Cao Rongrong , Liu Sen , Li Qingjiang
Published: August 2020

The activation function is a crucial part for memristive neural networks. For the first time, we propose a memristor-based activation function by using the natural non-linear characteristics of the memristor itself. Compared to the virtual ground circuit in traditional memristive neural networks, the feedback resistance was replaced by the W/TaOx/Ru memristor with no additional expense. Simulation results demonstrate that the proposed memristor-based activation function can achieve a performance similar to that of traditional activation functions on the Mixed National Institute of Standards and Technology database. In addition, an improvement in the recognition rate of up to 2% can be obtained in different neuromorphic networks by modulating the non-linearity of the memristor. Furthermore, the memristor-based activation function can also receive a 94% recognition rate even considering the non-ideal factors of the device.
A compact coaxial cusped periodic permanent magnet for a coaxial relativistic Čerenkov generator
Authors: Wu Xiaoling , Chen Changhua , Teng Yan , Li Xiaoze , Tan Weibing , Shi Yanchao , Zhu Xiaoxin , Zhang Ligang
Published: August 2020

A prototype of an integrated coaxial cusped periodic permanent magnet (CPPM) system is put forward and optimized. The guiding magnetic field strength and period of the CPPM are 0.32 T and 30 mm, respectively, and the whole focusing system is 240 mm long, with a maximum diameter of 170 mm and total weight of under 30 kg. Using this focusing system, an oversized Ku-band coaxial relativistic Čerenkov generator is proposed and investigated. Particle-in-cell simulation shows that the microwave with an output power of 830 MW at 15.29 GHz is achieved, yielding a conversion efficiency of 37%. The feasibility of CPPM applications in high power microwave (HPM) generation is confirmed, providing a new technical route for small, lightweight HPM generators.
Exotic closure domains induced by oxygen vacancies in compressed BaTiO3 nanofilm
Authors: Peng Di , Yang Xinhua , Jiang Wenkai
Published: August 2020

The molecular dynamics method based on the shell model is used to investigate the polarization configuration evolution in compressed BaTiO3 nanofilms with oxygen vacancy lattices of different volume fractions and positions. A clockwise closure domain surrounding a head-to-head domain is observed for a single oxygen vacancy nanofilm. With an increasing oxygen vacancy fraction, the closure domain around the vacancy becomes larger and gradually transforms its rotation direction from clockwise to counterclockwise. Inside the vacancy, except for the head-to-head domain remaining unchanged, the domain changes from a random configuration to a clockwise vortex, and finally to a segmented strip polydomain with 90°- and 180°-domain walls. For a single oxygen vacancy, its location region where the closure domain can occur is obtained, and the model center is a favored site for clockwise vortex nucleation. The closure domain partly changes its orientation if the oxygen vacancy shifts off the model center. In addition, homogeneous closure domains can occur when the vacancy changes its location within a small area. This study demonstrates the feasibility of tuning this kind of closure domain in ferroelectric nanofilms through external loadings and oxygen vacancies. This could be instructive to develop novel nanoscale memories and logic devices.
Aquifer vulnerability using geophysical and physiochemical methods in parts of Ethiope West Local Government Area of Delta State, Nigeria
Authors: Oseji Julius Otutu , Egbai James C. , Angela Emuobonuvie Ijeh–Edoso
Published: August 2020

Supply of potable water in Oghara communities in particular and parts of Ethiope West Local Government Area of Delta State in general is inadequate as a result of increasing population and development activities in the area. This can be resolved and sustained if groundwater resources are effectively managed. This study was carried out to determine the aquifer vulnerability and groundwater quality using geophysical and physiochemical methods in parts of Ethiope West Local Government Area, Delta State. Thirty vertical electrical soundings and four dipole–dipole profiling were administered using Abem Terrameter SAS 1000 AB. The field data were curve matched and iterated using WinResist and Dipro software. The aquiferous zone was found in the fourth layer with resistivity ranging from 159 Ωm to 100234 Ωm, thickness ranging from 12 m to 156 m, and depth ranging from 32 m to 162 m except VES 25, whose aquifer is in the third layer. The dipole–dipole resistivity structure shows low resistivity values along areas where waste dump was sited with resistivity ranging from 300 Ωm to 630 Ωm. This finding suggests that the leachate from the dumpsite is affecting the characteristics possessed by the subsurface close to it. The first order geoelectric and Dar-Zarrouk parameter study of aquifer protective capacity revealed a protection capacity value less than 0.1 for VESs 1–18 and 20–30, while VES 19 revealed a value of 0.24. Thus, Oghara communities are extremely unprotected, and the aquifer is prone to contamination. The physiochemical analysis carried out indicates that groundwater is slightly acidic with a pH value ranging from 5.40 to 6.40 when compared with the WHO permissible limit. The groundwater flow direction is depicted from the east to the west; this will assist policy planners to decide where dumpsites and companies generating waste could be sited to preserve groundwater potential.
Fully transparent GaN homojunction tunnel junction-enabled cascaded blue LEDs
Authors: Jamal-Eddine Zane , Hasan Syed M. N. , Gunning Brendan , Chandrasekar Hareesh , Crawford Mary , Armstrong Andrew , Arafin Shamsul , Rajan Siddharth
Published: August 2020

A sidewall activation process was optimized for buried magnesium-doped p-GaN layers yielding a significant reduction in tunnel junction-enabled light emitting diode (LED) forward voltage. This buried activation enabled the realization of cascaded blue LEDs with fully transparent GaN homojunction tunnel junctions. The initial optimization of buried p-GaN activation was performed on PN junctions grown by metal organic chemical vapor deposition (MOCVD) buried under hybrid tunnel junctions grown by MOCVD and molecular beam epitaxy. Next the activation process was implemented in cascaded blue LEDs emitting at 450 nm, which were enabled by fully transparent GaN homojunction tunnel junctions. The tunnel junction-enabled multi-active region blue LEDs were grown monolithically by MOCVD. This work demonstrates a state-of-the-art tunnel junction-enabled cascaded LED utilizing homojunction tunnel junctions which do not contain any heterojunction interface.
A practical guide for crystal growth of van der Waals layered materials
Authors: May Andrew F. , Yan Jiaqiang , McGuire Michael A.
Published: August 2020

This Tutorial provides an overview of the techniques that are most commonly utilized to grow bulk van der Waals crystals. The materials discussed were selected to highlight various challenges that are often encountered during crystal growth. In relatively equal parts, the text covers melt-based techniques, vapor transport growths, and the characterization of crystal quality with an emphasis on structural and chemical homogeneities. Pertinent details are given regarding the growth and characterization of many specific compounds, with examples mostly drawn from our own research, and an effort is made to highlight cases where the growths offer a particular lesson or the conditions have a significant impact on the crystal’s physical properties. A primary goal is to motivate more researchers to grow crystals by providing general descriptions and considerations for different growth techniques and equipment while sharing some of our own lessons learned and best practices for the growth and characterization of layered van der Waals crystals. The Tutorial is not written solely for aspiring crystal growers, however, because any researcher who collaborates with a crystal grower can benefit from having a greater understanding and appreciation of the processes of crystal growth and materials development.
Quadruple Beltrami state in electron-depleted multi-ion dusty plasmas
Authors: Gondal S. M. , Iqbal M.
Published: August 2020

In magnetized electron-depleted multi-ion dusty plasmas, a possibility of self-organization is determined. Making use of the equation of motion of the plasma's mobile species, i.e., a positive ion and two types of negative ions with Ampère's law, we obtain a quadruple Beltrami field. This higher order Beltrami field is characterized by four scale parameters. We have investigated the generation of self-organized structures. The typical length of these structures is attributed to the skin depth λp of positive ions. The influence of Beltrami parameters and scale parameters on the structure formation has also been investigated. It is found that there is a possibility of the formation of large scale structures of the order of system size and the formation of small scale structures of the order of skin depth simultaneously in the electron depleted multi-ion dusty plasmas, which are very useful to explain the dynamo theory. This study should be useful to describe the relaxed structures in space plasmas such as the D-region of Earth's mesosphere and F-ring of Saturn and in laboratory work where the dust particles are present as impurities.
Controllable coherent absorption of counterpropagating laser beams in organic microcavities
Authors: Schmidt Christoph , Sudzius Markas , Meister Stefan , Fröb Hartmut , Leo Karl
Published: August 2020

We investigate coherent perfect absorption in a microcavity with C60 as an organic absorbing material. The experiment consists of a two-beam setup of counterpropagating laser beams incident on a single sample from opposite sides, resulting in two counterpropagating outputs consisting of the reflected and transmitted parts of the incident beams. The systematic behavior of the output intensities as a function of the relative phase of incident beams and the thickness of the absorbing cavity layer is investigated. We experimentally verify that the absorption resonance of the cavity is accompanied by a transition of the phase difference of the individual outputs, which is characterized by a passage from out-of-phase to in-phase behavior of the outputs for varying relative phases of incident beams. The analysis shows that the amplitudes and offsets of the outputs qualitatively follow the theoretical model.
A temporal record of the past with a spectrum of time constants in the monkey entorhinal cortex
Authors: Bright Ian M. , Meister Miriam L. R. , Cruzado Nathanael A. , Tiganj Zoran , Buffalo Elizabeth A. , Howard Marc W.
Published: August 2020

Significance

Many brain regions, notably the hippocampus, contain a record of the recent past with time cells, neurons that fire in sequence, each at a specific time after a triggering event. The origin of this neural timeline has been unclear. This paper reports a timing signal in the entorhinal cortex (EC), which provides input to the hippocampus. Rather than firing sequentially, all EC neurons activated shortly after a stimulus and then decayed at a variety of rates. Because different neurons decay at different rates, one can reconstruct how far in the past the stimulus was presented by noting which neurons are still active. These results align well with the theoretical proposal that the brain represents the real Laplace transform of the past.
Optimizing immunization protocols to elicit broadly neutralizing antibodies
Authors: Sprenger Kayla G. , Louveau Joy E. , Murugan Pranav M. , Chakraborty Arup K.
Published: August 2020

Significance

The global health burden could be substantially alleviated by the creation of universal vaccines against highly mutable pathogens like HIV and influenza. Broadly neutralizing antibodies (bnAbs) are encouraging targets for such vaccines, because they can bind to diverse strains of these pathogens. BnAbs typically develop only after the immune system has been exposed to many mutated versions of a pathogen, and then too in few people and low numbers. Thus, sequentially administering multiple different pathogen-like proteins is a promising strategy to elicit bnAbs through vaccination. However, it remains unclear how best to design/administer these proteins. We explore this using physics-based simulations and provide mechanistic insights into antibody evolution that could guide creation of universal vaccines against highly mutable pathogens.
Loss of Hap1 selectively promotes striatal degeneration in Huntington disease mice
Authors: Liu Qiong , Cheng Siying , Yang Huiming , Zhu Louyin , Pan Yongcheng , Jing Liang , Tang Beisha , Li Shihua , Li Xiao-Jiang
Published: August 2020

Significance

A variety of neurodegenerative diseases show selective neuronal loss in distinct brain regions. It remains unclear how the ubiquitously expressed disease proteins can cause selective neurodegeneration. In Huntington’s disease, neuronal loss preferentially occurs in the striatum. Using Huntington’s disease mice, we found that loss of Hap1 selectively causes neuronal degeneration in the striatum. We further identified that this selective neuronal degeneration also depends on mutant HTT and Rhes, a striatal enriched protein. Hap1 deficiency causes more Rhes to bind mutant HTT to yield a toxic form of mutant HTT. Our findings suggest that multiple factors are involved in the selective neuronal loss in neurodegenerative diseases and that their specific interaction can serve as a therapeutic target.
Nanoscale force sensing of an ultrafast nonlinear optical response
Authors: Schumacher Zeno , Rejali Rasa , Pachlatko Raphael , Spielhofer Andreas , Nagler Philipp , Miyahara Yoichi , Cooke David G. , Grütter Peter
Published: August 2020

Significance

Optical properties of materials are governed by nanoscale charge motion induced by ultrafast light fields. Here, we demonstrate that the electrostatic force originating from light-induced electron motion in a dielectric can be measured using atomic force microscopy. We observe changes in the force originating from second-order nonlinear optical interactions in the sample on a sub-15-nm scale and 100-fs time resolution. The time resolution is set by the light pulse characteristics, not by the properties of the force sensor. Our method does not rely on nonlinear tip–sample interactions, thus advancing the possibility to observe ultrafast nonlinear light–matter interactions with spatial resolution in any material. We envision this technique will allow the correlation of nanometer structure with light-induced time-resolved kinetics.
Hidden kinetic traps in multidomain folding highlight the presence of a misfolded but functionally competent intermediate
Authors: Gautier Candice , Troilo Francesca , Cordier Florence , Malagrinò Francesca , Toto Angelo , Visconti Lorenzo , Zhu Yanlei , Brunori Maurizio , Wolff Nicolas , Gianni Stefano
Published: August 2020

Significance

Much of our current knowledge on protein folding is based on work focused on isolated domains. In this study, using a combination of NMR and kinetic experiments, we depict the folding pathway of a multidomain construct comprising two PDZ domains in tandem, belonging to the protein Whirlin. We demonstrate the presence of a misfolded intermediate that competes with productive folding. Interestingly, we show that, unexpectedly, this misfolded state retains the native-like functional ability to bind its physiological ligand, representing a clear example of a functionally competent misfolded state. On the basis of these results and a comparative analysis of the amino acidic sequences of Whirlin from different species, we propose a possible physiological role of the misfolded intermediate.
Social bonds do not mediate the relationship between early adversity and adult glucocorticoids in wild baboons
Authors: Rosenbaum Stacy , Zeng Shuxi , Campos Fernando A. , Gesquiere Laurence R. , Altmann Jeanne , Alberts Susan C. , Li Fan , Archie Elizabeth A.
Published: August 2020

Significance

In humans and other social animals, early life adversity and weak social relationships can both alter adult stress responses. The causal connections between these variables are debated; resolving this debate requires data on all three variables in the same individuals. Here, we unite these components in wild female baboons. We find that early adversity elevates adult females’ glucocorticoid levels, one measure of the stress response. This effect was largely explained by the direct effect of early adversity on glucocorticoids and was not mediated by poor social relationships in adulthood. Hence, early adversity and adult social relationships appear to have independent effects on adult stress responses.
The creative cliff illusion
Authors: Lucas Brian J. , Nordgren Loran F.
Published: August 2020

Significance

Creativity research across the social sciences seeks to elucidate factors that enhance and stifle creativity. We demonstrate that people systematically misunderstand their own creativity across an ideation session. Eight studies found that people expect their creativity to decline across an ideation session when it, in fact, tends to improve or persist (we call this misprediction the creative cliff illusion). These beliefs are consequential because they lead people to undervalue ideation: They exhibit less task persistence and lower creative performance. This research documents a fundamental disconnect between people’s beliefs and the reality of how creativity emerges over time. It demonstrates the value of understanding creativity beliefs and has implications for facilitating creativity in individuals and their organizations and institutions.
Small proteins regulate
Salmonella
survival inside macrophages by controlling degradation of a magnesium transporter
Authors: Yeom Jinki , Shao Yi , Groisman Eduardo A.
Published: August 2020

Significance

The murine protein Slc11a1 (SLC11A1 in humans) hinders replication of invading microbes by provoking Mg
2+
limitation in host tissues. To withstand Mg
2+
limitation and to promote survival in
Slc11a1
+
/
+
macrophages, the intracellular pathogen
Salmonella enterica
serovar Typhimurium requires MgtB, one of its three Mg
2+
transporters and the only one absent from commensal
Escherichia coli
. Although MgtB is 50% identical to the Mg
2+
transporter MgtA, the latter is dispensable for virulence and exhibits different activity and specificity. When
Salmonella
experiences Mg
2+
limitation, the combined activities of the small proteins MgtR and MgtU result in MgtB stabilization and MgtA proteolysis.
Explaining the low-frequency shear elasticity of confined liquids
Authors: Zaccone Alessio , Trachenko Kostya
Published: August 2020

Experimental observations of unexpected shear rigidity in confined liquids, on very low frequency scales on the order of 0.01 to 0.1 Hz, call into question our basic understanding of the elasticity of liquids and have posed a challenge to theoretical models of the liquid state ever since. Here we combine the nonaffine theory of lattice dynamics valid for disordered condensed matter systems with the Frenkel theory of the liquid state. The emerging framework shows that applying confinement to a liquid can effectively suppress the low-frequency modes that are responsible for nonaffine soft mechanical response, thus leading to an effective increase of the liquid shear rigidity. The theory successfully predicts the scaling law

G

′

∼

L

−
3

for the low-frequency shear modulus of liquids as a function of the confinement length

L

, in agreement with experimental results, and provides the basis for a more general description of the elasticity of liquids across different time and length scales.
Convergent evolution of processivity in bacterial and fungal cellulases
Authors: Uchiyama Taku , Uchihashi Takayuki , Nakamura Akihiko , Watanabe Hiroki , Kaneko Satoshi , Samejima Masahiro , Igarashi Kiyohiko
Published: August 2020

Significance

Some cellulases exhibit “processivity”: the ability to degrade crystalline cellulose through successive hydrolytic catalytic reactions without the release of the enzyme from the substrate surface. We previously observed the movement of fungal processive cellulases by high-speed atomic force microscopy, and here, we use the same technique to directly observe the processive movement of bacterial cellobiohydrolases settling a long-standing controversy. Although fungal and bacterial processive cellulases have completely different protein folds, they have evolved to acquire processivity through the same strategy of adding subsites to extend the substrate-binding site and forming a tunnel-like active site by increasing the number of loops covering the active site. This represents an example of protein-level convergent evolution to acquire the same functions from different ancestors.
Interpreting emoji pragmatics
Authors: Dainas Ashley R. , Herring Susan C.
Published: August 2020

This chapter describes the methods and the overall findings of
the Understanding Emoji Survey, which we administered online in early 2018 to
determine how social media users interpret the pragmatic functions of popular emoji
types in the discourse context of comments posted to public Facebook groups. The
findings generally validate Herring and Dainas’s
(2017) taxonomy of graphicon functions for emoji, although survey
respondents (n = 523) overwhelmingly preferred one function,
tone modification, over the others. Moreover, preferred
interpretations of pragmatic function varied according to emoji type. Based on these
findings, we argue for the importance of analyzing emoji meaning from the
perspective of pragmatics.
Inviting a purchase
Authors: Xie Chaoqun , Tong Ying
Published: August 2020

The present study investigates the pragmatic strategies and
effects of self-presentation performance in a social selling context either by way
of status updates or through group chat in WeChat, a popular social networking
platform in China. Drawing on Goffman’s (1959, 1974, 1981) outstanding research on
self-presentation, frame, and footing, as well as Page’s (2010a, 2010b, 2012, 2018) exploration in digital narrative, this chapter
analyzes data collected from WeChat Moments and WeChat chat logs to uncover their
staged authenticity and the relative social value that it entails. The results of
our analysis of both screen data and user data show that the meticulously
intertwined and multimodally presented communicative acts of social selling on this
particular social platform are the outcome of frame-shifting and frame-overlapping
strategies on the one hand and highly crafted staged authenticity on the other.
A study on how cultural and gender parameters affect emoticon distribution,
usage and frequency in American and Japanese online discourse
Authors: Kavanagh Barry
Published: August 2020

This study attempts to understand how cultural and gender
parameters affect emoticon distribution, usage and frequency in American and
Japanese online discourse. From a corpus of American and Japanese personal blog
comments of over 45,000 sentences and data from interviews with bloggers, emoticon
function, usage and frequency were compared across gender and cross-culturally. In
addition, an examination of how emoticons interact with the linguistic text and
other unconventional means of communication such as unconventional phonetic
spelling, was also given consideration.