bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Factors and Sociotechnical Issues
Authors: Pelayo Sylvia , Senathirajah Yalini ,   Section Editors for the IMIA Yearbook Section on Human Factors and Organizational Issues
Published: August 2019

Objective: To summarize significant research contributions on human factors (HF) and organizational issues in medical informatics published in 2018.

Methods: An extensive search using PubMed/Medline and Web of Science® was conducted to identify the scientific contributions published in 2018 that address human factors and organizational issues in medical informatics. The selection process comprised three steps: (i) 15 candidate best papers were first selected by the two section editors, (ii) external reviewers from internationally renowned research teams reviewed each candidate best paper, and (iii) the final selection of four best papers was conducted by the editorial board of the Yearbook.

Results: The four selected best papers are excellent contributions to the HF literature: they show the added value of HF studies by providing nice illustrated and rigorous interventions.

Conclusion: HF interventions are known to have great potential to contribute to efficient HIT design, but the interventions still face challenges in successfully demonstrating their value to the main stakeholders of the healthcare domain. There is a need to strengthen the demand for high-quality HF studies by increasing awareness among powerful stakeholders of the value of high-quality HF studies.
Formal Medical Knowledge Representation Supports Deep Learning Algorithms, Bioinformatics Pipelines, Genomics Data Analysis, and Big Data Processes
Authors: Dhombres Ferdinand , Charlet Jean ,   Section Editors for the IMIA Yearbook Section on Knowledge Representation and Management
Published: August 2019

Objective: To select, present, and summarize the best papers published in 2018 in the field of Knowledge Representation and Management (KRM).

Methods: A comprehensive and standardized review of the medical informatics literature was performed to select the most interesting papers published in 2018 in KRM, based on PubMed and ISI Web Of Knowledge queries.

Results: Four best papers were selected among the 962 publications retrieved following the Yearbook review process. The research areas in 2018 were mainly related to the ontology-based data integration for phenotype-genotype association mining, the design of ontologies and their application, and the semantic annotation of clinical texts.

Conclusion: In the KRM selection for 2018, research on semantic representations demonstrated their added value for enhanced deep learning approaches in text mining and for designing novel bioinformatics pipelines based on graph databases. In addition, the ontology structure can enrich the analyses of whole genome expression data. Finally, semantic representations demonstrated promising results to process phenotypic big data.
Artificial Intelligence for Surveillance in Public Health
Authors: Thiébaut Rodolphe , Cossin Sébastien ,   Section Editors for the IMIA Yearbook Section on Public Health and Epidemiology Informatics
Published: August 2019

Objectives: To introduce and summarize current research in the field of Public Health and Epidemiology Informatics.

Methods: The 2018 literature concerning public health and epidemiology informatics was searched in PubMed and Web of Science, and the returned references were reviewed by the two section editors to select 15 candidate best papers. These papers were then peer-reviewed by external reviewers to give the editorial team an enlightened selection of the best papers.

Results: Among the 805 references retrieved from PubMed and Web of Science, three were finally selected as best papers. All three papers are about surveillance using digital tools. One study is about the surveillance of flu, another about emerging animal infectious diseases and the last one is about foodborne illness. The sources of information are Google news, Twitter, and Yelp restaurant reviews. Machine learning approaches are most often used to detect signals.

Conclusions: Surveillance is a central topic in public health informatics with the growing use of machine learning approaches in regards of the size and complexity of data. The evaluation of the approaches developed remains a serious challenge.
Research on life evaluation method of solder joint based on eddy current pulse thermography
Authors: Zhou Xiuyun , Lu Xiaochuan , Cao Xiaohan , Liu Zhen , Chen Yaqiu
Published: August 2019

With the wide usage of electronic packaging technologies such as Ball Grid Array in electronic industry, it is necessary to maintain its quality in order to meet the demand of electronic products for function, integration, and size reduction. However, as the size of solder joints in such technology decreases, the solder joints are more and more prone to defects. To solve the life prediction problem of small-size packages having interconnections in the high-density chip, a method based on the eddy current pulsed thermography (ECPT) is put forward to study the remaining life prediction of solder joints. A 3D induction heating finite element model is established, by which the crack length of defect solder joints can be distinguished using temperature field. At the same time, the remaining life of defect solder joints can be characterized by the length of the crack. Furthermore, the experiments are carried out on solder joints whose diameter is 0.4 mm. Both simulation and experiment results verify that it is reliable and convenient to use 3D induction heating based temperature field from ECPT to evaluate the remaining life of cracks in solder joints.
Plume dynamics and gas-phase molecular formation in transient laser-produced uranium plasmas
Authors: Skrodzki P. J. , Burger M. , Jovanovic I. , Phillips M. C. , Yeak J. , Brumfield B. E. , Harilal S. S.
Published: August 2019

The dynamics of expansion, thermodynamics, and chemical reactions in laser-produced plasmas is of general interest for all laser ablation applications. This study investigates the complex morphology and behavior of reactive species in nanosecond laser-produced uranium plasmas. Comparing plasma morphology in various inert and reactive ambient gases provides information about the role of gas-phase chemistry in plume hydrodynamics. Background gases including nitrogen and argon foster collisional interactions leading to more significant plume confinement and the increase in persistence of uranium species. On the other hand, environments containing reactive gases such as oxygen promote chemical reactions between the plasma and ambient species. By comparing the expansion dynamics of uranium plumes in nitrogen, air, and argon, we discover that chemical reactions modify the hydrodynamics of the plume at later times of its evolution in the air background. Furthermore, we observe that varying the concentration of oxygen in the fill gas promotes different reaction pathways that lead to the formation of uranium oxides. The reaction pathways from atoms to diatomic to polyatomic molecules strongly vary with ambient oxygen concentration. Lower oxygen concentrations enhance the formation of uranium monoxide from atomic uranium, whereas higher oxygen concentrations tend to depopulate both atomic uranium and uranium monoxide concentrations through the formation of more complex uranium oxides.
Effects of vacancies and p-doping on the optoelectronic properties of Cu- and Ag-based transparent conducting oxides
Authors: Shook James , Borges Pablo D. , Scolfaro Luisa M. , Geerts Wilhelmus J.
Published: August 2019

First principles band structure calculations are employed to perform a comprehensive study of the electronic and optical properties of the 2H-phase XTO2 (X = Cu, Ag; T = Al, Cr) delafossites, and the effects on those properties due to Cu, Ag, and O vacancies, as well as p-type doping with magnesium. From the band structures, the frequency-dependent real and imaginary parts of the complex dielectric function, ϵ(ω), are obtained, together with refractive index, extinction coefficient, optical conductivity, reflectivity, absorption coefficient, and energy loss function. Moreover, hole effective masses are calculated for all systems and are shown to be highly anisotropic. Comparisons between the results obtained in this work and previous experimental and other theoretical results are made, when available. X vacancies and Mg doping are predicted to only marginally affect the transparent character, but are also predicted to increase the hole effective mass. O vacancies are predicted to lower the hole effective mass, but at the cost of increased absorption in the optical portion of the spectrum, harming transparent character.
Dependence of tribological behavior of GaN crystal on loading direction: A molecular dynamics study
Authors: Qian Yu , Deng Shizhe , Shang Fulin , Wan Qiang , Yan Yabin
Published: August 2019

In order to investigate the tribological property of the gallium nitride (GaN) crystal at the nanoscale, a series of molecular dynamics nanoscratch simulations are carried out on the surfaces of c-GaN, a-GaN, and m-GaN. The key factors of scratch depth and scratch direction that greatly influence the deformation behavior are explored by analyzing the mechanical response, surface wear, and subsurface dislocation nucleation. The friction coefficient, wear rate, and total length of dislocations are all found to increase with the increase of scratch depth. A clear directional dependence could be recognized for c-GaN, where the friction coefficient along the [101¯0] direction is always lower than that along the [12¯10] direction, and the wear rate along the [101¯0] direction is higher than that along the [12¯10] direction, regardless of the scratch depth. On the contrary, the directional dependence of the wear rate and friction coefficient is unclear for a-GaN and m-GaN. For scratches at a specific depth, dislocations in c-GaN are smallest in length and occupy shallow positions close to the surface, while widely distributed dislocations could be observed in m-GaN.
Sub-Kelvin (100 mK) time resolved electron paramagnetic resonance spectroscopy for studies of quantum dynamics of low-dimensional spin systems at low frequencies and magnetic fields
Authors: Cebulka Rebecca , Del Barco Enrique
Published: August 2019

This article presents a time-resolved electron paramagnetic resonance spectrometry setup designed to work at frequencies below 20 GHz and temperatures down to 50 mK. The setup consists of an on-chip microstrip resonator (Q < 100) placed in a dilution cryostat located within a superconducting 3D vector magnet. A housemade spin echo circuitry controlled by a microwave network analyzer, a pulse pattern generator, and an oscilloscope connects to the microstrip through a series of copper, stainless steel, and superconducting semirigid coaxial lines which are thermally anchored to the different cooling stages of the fridge by means of power attenuators, circulators, and a cryogenic amplifier. Spin echo experiments were performed at a 0.5-T magnetic field on a spin 1 2 paramagnetic coal marker sample mounted on a 15 GHz microstrip resonator at temperatures ranging from 100 to 800 mK. The results show an increase in echo signal intensity as temperature is decreased until saturation as theoretically expected in reaching 99% spin polarization at 100 mK. Our technique allows tuning of the spin system in the pure-state regime and minimizing dipolar fluctuations, which are the main contribution to decoherence in solid-state samples of single-molecule magnets (SMMs) - molecular spin systems that are currently being tested for applications in quantum computation. The achievement of full spin polarization at 100 mK will allow for coherent control over the time evolution of spin systems without the need for large magnetic fields (commonly used to polarize the dipolar bath at higher temperatures) and high frequencies.
Comparison of simulation and experiments for multimode aerodynamic breakup of a liquid metal column in a shock-induced cross-flow
Authors: Arienti Marco , Ballard Matthew , Sussman Mark , Mazumdar Yi Chen , Wagner Justin L. , Farias Paul A. , Guildenbecher Daniel R.
Published: August 2019

While the mechanisms that drive breakup and aerodynamic dispersion of traditional liquids such as water have been extensively studied, it is not yet clear if models for traditional liquids can be used to accurately describe the behavior of molten metals. In this paper, multiphase simulations with the interface-capturing combined level-set volume-of-fluid approach are used to provide time-resolved morphology and breakup data for a liquid column subject to a shock-induced cross-flow. For the first time, numerical simulation of the behavior of a liquid metal (Galinstan alloy composed of gallium, indium, and tin) is compared to the well-documented behavior of water. Simulations consider a gas cross-flow Weber number between 10 and 12, which produces a multimode breakup morphology consisting of multiple baglike structures. Up to bag breakup, we confirm that the deformation rate of Galinstan follows the same dependence on the gas cross-flow Weber number as ordinary liquids when time is nondimensionalized by including the liquid-gas density ratio. Moreover, we determine that the appearance of a central stem along the column upstream surface in multimode bag breakup is consistent with the occurrence of Rayleigh-Taylor instability. We also resolve bag stretching and fragmentation, to the full extent allowed by our computational resources, and carry out a direct comparison with the measurements of size and velocity of secondary droplets from high-speed digital inline holography. For Galinstan, we illustrate the differences between simulation and experiment that emerge because of the modification of the surface properties of the metal exposed to air.
Numerical study of transition between even and odd toroidal Alfvén eigenmodes on EAST
Authors: Hou Yawei , Kim Charlson C. , Zhu Ping , Zou Zhihui , Hu Youjun , Yan Xingting ,   NIMROD Team
Published: August 2019

Linear simulations of toroidal Alfvén eigenmodes (TAEs) driven by energetic particles (EPs) on EAST (Experimental Advanced Superconducting Tokamak) are performed using the hybrid-kinetic MHD model implemented in NIMROD code. The EAST equilibrium is reconstructed using the EFIT code based on the experimental measurement. The “slowing down” distribution is adopted for modeling the equilibrium distribution of the energetic ions from the deuterium neutral beam injection on EAST. The frequency, the dominant poloidal mode number, the radial location and the detailed 2D mode structure of the TAE/RSAE (Reverse Shear Alfvén Eigenmode)/EPM (energetic particle mode) modes are consistent between the eigenvalue analysis and the NIMROD simulation. As the β fraction of EP increases, a transition between even and odd TAEs occurs, along with that between the ballooning and antiballooning mode structures. When the β fraction of EP is close to the transition threshold, both types of TAEs coexist.
Stability of slip channel flow revisited
Authors: Chai Chunshuo , Song Baofang
Published: August 2019

In this work, we revisit the temporal stability of slip channel flow. Lauga and Cossu [“A note on the stability of slip channel flows,” Phys. Fluids 17, 088106 (2005)] and Min and Kim [“Effects of hydrophobic surface on stability and transition,” Phys. Fluids 17, 108106 (2005)] have investigated both modal stability and non-normality of slip channel flow and concluded that the velocity slip greatly suppresses linear instability and only modestly affects the non-normality. Here, we study the stability of channel flow with streamwise and spanwise slip separately as two limiting cases of anisotropic slip and explore a broader range of slip length than previous studies did. We find that, with a sufficiently large slip, both streamwise and spanwise slip trigger three-dimensional leading instabilities. Overall, the critical Reynolds number is only slightly increased by streamwise slip, whereas it can be greatly decreased by spanwise slip. Streamwise slip suppresses the nonmodal transient growth, whereas the spanwise slip enlarges the nonmodal growth, although it does not affect the base flow. Interestingly, as the spanwise slip length increases, the optimal perturbations exhibit flow structures different from the well-known streamwise rolls. However, in the presence of equal slip in both directions, the three-dimensional leading instabilities disappear and the flow is greatly stabilized. The results suggest that earlier instability and larger transient growth can be triggered by introducing anisotropy in the velocity slip.
Statistical analysis of vortical structures in turbulent boundary layer over directional grooved surface pattern with spanwise heterogeneity
Authors: Xu Fang , Zhong Shan , Zhang Shanying
Published: August 2019

We examine the turbulent boundary layers developing over convergent-divergent riblets (C-D riblets) with three different heights (h+ = 8, 14, and 20) at Reθ = 723 using particle image velocimetry. It is observed that although a logarithmic region presents in the velocity profiles over the converging and diverging line, Townsend’s outer-layer similarity hypothesis is invalid. Compared to the smooth-wall case, C-D riblets with a height of 2.4% of the smooth-wall boundary layer thickness can cause a significant increase in the turbulence production activities over the converging region, as evidenced by a more than 50% increase in the turbulent shear stress and in the population of prograde and retrograde spanwise vortices. In contrast, the impact of riblets on the diverging region is much smaller. The slope of vortex packets becomes steeper, and they are more streamwise stretched in the outer layer over the diverging region, whereas their shape and orientation is less affected over the converging region. Furthermore, the number of uniform momentum zones across the boundary layer increases over the converging region, causing a reduction in the thickness of uniform momentum zones in the outer part of the boundary layer. Overall, while an increased riblet height affects a large portion of the boundary layer away from the wall over the converging region, the impact on the diverging region is largely confined within the near-wall region. Such distinct differences in the response of the boundary layer over the diverging and converging region are attributed to the opposite local secondary flow motion induced by C-D riblets.
Development of an impulsive model of dissociation in direct simulation Monte Carlo
Authors: Luo Han , Alexeenko Alina A. , Macheret Sergey O.
Published: August 2019

A previously proposed classical impulsive model for dissociation of diatomic molecules in direct simulation Monte Carlo (DSMC), the Macheret-Fridman for direct simulation Monte Carlo (MF-DSMC) model [Luo et al., “Classical impulsive model for dissociation of diatomic molecules in direct simulation Monte Carlo,” Phys. Rev. Fluids 3, 113401 (2018)], is extended in this work. To improve the prediction of state-specific rates at high vibrational energy, the anharmonic vibrational phase angle distribution function is first incorporated into the model. Then, to improve the prediction of thermal equilibrium dissociation rates, the general concept of calculating total collision cross sections with the MF-DSMC model is discussed and the framework of implementing a collision model based on exponential potential is constructed. The improved model is validated by comparisons with quasiclassical trajectory calculations, empirical estimations, and experimental measurements. In general, better agreement compared with the original version of the model is obtained. The improved model is also evaluated by simulating O2 reacting shock experiment.
Tuning emission energy and fine structure splitting in quantum dots emitting in the telecom O-band
Authors: Höfer B. , Olbrich F. , Kettler J. , Paul M. , Höschele J. , Jetter M. , Portalupi S. L. , Ding F. , Michler P. , Schmidt O. G.
Published: August 2019

We report on optical investigations of MOVPE-grown InGaAs/GaAs quantum dots emitting at the telecom O-band that were integrated onto uniaxial piezoelectric actuators. This promising technique, which does not degrade the emission brightness of the quantum emitters, enables us to tune the quantum dot emission wavelengths and their fine-structure splitting. By spectrally analyzing the emitted light with respect to its polarization, we are able to demonstrate the cancelation of the fine structure splitting within the experimental resolution limit. This work represents an important step towards the high-yield generation of entangled photon pairs at telecommunication wavelength, together with the capability to precisely tune the emission to target wavelengths.
A unified model of mean-time-to-failure for electromigration, thermomigration, and stress-migration based on entropy production
Authors: Tu K. N. , Gusak A. M.
Published: August 2019

We have revisited Black's equation of mean-time-to-failure (MTTF) for electromigration from the viewpoint that in irreversible processes, entropy production is the controlling behavior. We justify that the power factor on current density is n = 2, as given in the original Black's equation. Furthermore, on the basis of entropy production, we provide a unified model of MTTF for thermomigration and stress-migration. We note that up to now, no MTTF for thermomigration and stress-migration is given.
Substitutional Si impurities in monolayer hexagonal boron nitride
Authors: Ahmadpour Monazam Mohammad Reza , Ludacka Ursula , Komsa Hannu-Pekka , Kotakoski Jani
Published: August 2019

We report the observation of substitutional silicon atoms in single-layer hexagonal boron nitride (h-BN) using aberration corrected scanning transmission electron microscopy. The images reveal silicon atoms exclusively filling boron vacancies. Density functional theory is used to study the energetics, structure, and properties of the experimentally observed structure. The formation energies reveal SiB+1 as the most stable configuration. In this case, the silicon atom elevates by 0.66 Å out of the lattice with unoccupied defect levels in the electronic bandgap above the Fermi level. Our results unequivocally show that heteroatoms can be incorporated into the h-BN lattice opening the way for applications ranging from single-atom catalysis to atomically precise magnetic structures.
Spin-orbit coupling from a two-component self-consistent approach. II. Non-collinear density functional theories
Authors: Desmarais Jacques K. , Flament Jean-Pierre , Erba Alessandro
Published: August 2019

We revise formal and numerical aspects of collinear and noncollinear density functional theory (DFT) in the context of a two-component self-consistent treatment of spin-orbit coupling (SOC). While the extension of the standard one-component theory to a noncollinear magnetization is formally well-defined within the local density approximation, and therefore results in a numerically stable theory, this is not the case within the generalized gradient approximation (GGA). Previously reported formulations of noncollinear DFT based on GGA exchange-correlation potentials have several limitations: (i) they fail at reducing (either formally or numerically) to the proper collinear limit (i.e., when the magnetization is parallel or antiparallel to the z axis everywhere in space); (ii) they fail at ensuring a quantitative rotational invariance of the total energy and even a qualitative rotational invariance of the spatial distribution of the magnetization when a SOC operator is included in the Hamiltonian; (iii) they are numerically very unstable in regions of small magnetization. All of the above-mentioned problems are here shown (both formally and through test examples) to be solved by using instead a new formulation of noncollinear DFT for GGA functionals, which we call the “signed canonical” theory, as combined with an effective screening algorithm for unstable terms of the exchange-correlation potential in regions of small magnetization. All methods are implemented in the CRYSTAL program and tests are performed on simple molecules to compare the different formulations of noncollinear DFT.

All three authors of the article agree to the retraction of the article effective April 16, 2021.
Charge-gradient instability of compressional dust lattice waves in electrorheological plasmas
Authors: Yaroshenko V. V.
Published: August 2019

It is shown that the longitudinal dust lattice mode in the one-dimensional string of microparticles oriented along the electric field (it highlights the major aspect of the electrorheological plasmas) can be subjected to a specific charge-gradient instability, associated with inhomogeneous dust charge distribution along the string due to the ion flow. This instability leads to the spontaneous excitation of compressional waves at elevated gas pressures with implications for the electrorheological plasmas studied in the Plasmakristall-4 facility in the ground based conditions and in microgravity on board the International Space Station. The obtained results can also be relevant for the stability analysis of the laboratory multilayer plasma crystals observed in the sheath of gas discharges.
Magneto-thermoelectric characterization of a HfTe5 micro-ribbon
Authors: Niemann Anna Corinna , Gooth Johannes , Sun Yan , Thiel Felix , Thomas Andy , Shekhar Chandra , Süß Vicky , Felser Claudia , Nielsch Kornelius
Published: August 2019

HfTe5 is a promising low-temperature thermoelectric material. Its thermoelectric power output has been investigated at different temperatures and with different dopants. Recently, research has focused on the nontrivial topological band structure of HfTe5. Whereas band structure simulations and angle-resolved photoemission spectroscopy experiments put HfTe5 at the transition between a weak and a strong topological insulator, observations of the chiral magnetic effect indicate that HfTe5 is instead a Dirac semimetal. In this study, we contribute to the investigation of transport phenomena in HfTe5 by magnetoresistance (MR) and magnetothermopower (MS) measurements on a single-crystalline HfTe5 microribbon measuring 20 μm × 2.1 μm × 0.7 μm, with a magnetic field applied perpendicular to the transport direction. Interestingly, we see an almost complete suppression of the thermopower for elevated magnetic fields at temperatures of T ≤ 100 K, while an increased magnetothermopower is observed for increasing magnetic fields at T ≥ 150 K. First, we analyze the magnetic field-dependence of the magnetoresistance and magnetothermopower for different temperatures and propose several possible transport mechanisms responsible for the vanishing magnetothermoelectric transport at low temperatures. Furthermore, we report on an increase in the thermoelectric power factor by up to 40% due to an applied magnetic field and for temperatures between 150 K and 300 K, which is the temperature range relevant for thermoelectric applications of HfTe5.
Addressing cellular heterogeneity in tumor and circulation for refined prognostication
Authors: Lim Su Bin , Yeo Trifanny , Lee Wen Di , Bhagat Ali Asgar S. , Tan Swee Jin , Tan Daniel Shao Weng , Lim Wan-Teck , Lim Chwee Teck
Published: August 2019

Despite pronounced genomic and transcriptomic heterogeneity in non–small-cell lung cancer (NSCLC) not only between tumors, but also within a tumor, validation of clinically relevant gene signatures for prognostication has relied upon single-tissue samples, including 2 commercially available multigene tests (MGTs). Here we report an unanticipated impact of intratumor heterogeneity (ITH) on risk prediction of recurrence in NSCLC, underscoring the need for a better genomic strategy to refine prognostication. By leveraging label-free, inertial-focusing microfluidic approaches in retrieving circulating tumor cells (CTCs) at single-cell resolution, we further identified specific gene signatures with distinct expression profiles in CTCs from patients with differing metastatic potential. Notably, a refined prognostic risk model that reconciles the level of ITH and CTC-derived gene expression data outperformed the initial classifier in predicting recurrence-free survival (RFS). We propose tailored approaches to providing reliable risk estimates while accounting for ITH-driven variance in NSCLC.
Silica catalyzed one pot synthesis of hybrid thiazolidin-4-one derivatives as anti-tubercular and anti-inflammatory agent by attenuating COX-2 pathway
Authors: Pathak Prateek , Shukla Parjanya Kumar , Naumovich Vladislav , Grishina Maria , Potemkin Vladimir , Verma Amita
Published: August 2019

A novel series of a hybrid class of hybrid thiazolidin-4-one derivatives were designed and synthesized through one-pot catalytic synthesis. The reaction was catalyzed in the presence of silica-H2SO4(+6). The derivatives computational ADMET profile was calculated.
The study shows that most active derivatives have optimal logP, higher anti-inflammatory activity score, and poor metabolism at the sight of P450-3A4 and 2D6. The entire series of derivatives were further evaluated for anti-tubercular (against Mycobacterium tuberculosis H37Rv (Resistant
strain)) and anti-inflammatory activity (in-vivo assay using Wistar rat). The result showed that derivatives 4c, 4h, and 4m have significant potency against tested M. tuberculosis. However, derivatives 4i and 4j found significantly active against inflammation.
In vitro COX inhibition assay also supported the result in favor of selectivity and efficacy of derivatives.
Microtubule minus-end stability is dictated by the tubulin off-rate
Authors: Strothman Claire , Farmer Veronica , Arpağ Göker , Rodgers Nicole , Podolski Marija , Norris Stephen , Ohi Ryoma , Zanic Marija
Published: August 2019

Dynamic organization of microtubule minus ends is vital for the formation and maintenance of acentrosomal microtubule arrays. In vitro, both microtubule ends switch between phases of assembly and disassembly, a behavior called dynamic instability. Although minus ends grow slower, their lifetimes are similar to those of plus ends. The mechanisms underlying these distinct dynamics remain unknown. Here, we use an in vitro reconstitution approach to investigate minus-end dynamics. We find that minus-end lifetimes are not defined by the mean size of the protective GTP-tubulin cap. Rather, we conclude that the distinct tubulin off-rate is the primary determinant of the difference between plus- and minus-end dynamics. Further, our results show that the minus-end–directed kinesin-14 HSET/KIFC1 suppresses tubulin off-rate to specifically suppress minus-end catastrophe. HSET maintains its protective minus-end activity even when challenged by a known microtubule depolymerase, kinesin-13 MCAK. Our results provide novel insight into the mechanisms of minus-end dynamics, essential for our understanding of microtubule minus-end regulation in cells.
A pathogenic role of plasmacytoid dendritic cells in autoimmunity and chronic viral infection
Authors: Barrat Franck J. , Su Lishan
Published: August 2019

Following the discovery of plasmacytoid dendritic cells (pDCs) and of their extraordinary ability to produce type I IFNs (IFN-I) in response to TLR7 and TLR9 stimulation, it is assumed that their main function is to participate in the antiviral response. There is increasing evidence suggesting that pDCs and/or IFN-I can also have a detrimental role in a number of inflammatory and autoimmune diseases, in the context of chronic viral infections and in cancers. Whether these cells should be targeted in patients and how much of their biology is connected to IFN-I production remains unclear and is discussed here.
Detecting Quantumness in the n-cycle Exclusivity Graphs*
Authors: Zhou Jie , Meng Hui-Xian , Chen Jing-Ling
Published: August 2019

Quantum contextuality is one kind of quantumness that distinguishes quantum mechanics from classical theory. As the simplest exclusivity graph, quantum contextuality of the n-cycle graph has been reviewed, while only for odd n the quantumness can be revealed. Motivated by this, we propose the degree of non-commutativity and the degree of uncertainty to measure the quantumness in the n-cycle graphs. As desired, these two measures can detect the quantumness of any n-cycle graph when n ≥ 4.
High-Brightness Low-Divergence Tapered Lasers with a Narrow Taper Angle*
Authors: Chen Zhong-Hao , Qu Hong-Wei , Ma Xiao-Long , Qi Ai-Yi , Zhou Xu-Yan , Wang Yu-Fei , Zheng Wan-Hua
Published: August 2019

High-brightness tapered lasers with photonic crystal structures are designed and fabricated. A narrow taper angle is designed for the tapered section. The device delivers an output power of 3.3 W and a maximum wall-plug efficiency of 43%. The vertical beam divergence is around 11° at different currents. Nearly diffraction-limited beam qualities for the vertical and lateral directions are obtained. The lateral beam quality factor M
2 is below 2.5 and the vertical M
2 value is around 1.5 across the whole operating current range. The maximum brightness is 85 MW·cm−2sr−1. When the current is above 3.3 A, the brightness is still above 80 MW·cm−2sr−1.
Preparation and 1.06 μm Fluorescence Decay of Nd3+-Doped Glass Ceramics Containing NaYF4 Nanocrystallites*
Authors: Huang Xing-Yong , Chen Da-Qin , Shen Bi-Zhou , Song Hai-Zhi
Published: August 2019

Considered to be a candidate for large-size bulk materials used in lasers and other fields, Nd3+-doped glass ceramics containing NaYF4 nanocrystallites are prepared. Using x-ray diffraction and transmission electron microscopy, we show that pure cubic NaYF4 is well precipitated in the glass matrix. To obtain the optical property of this material at 1.06 μm, the fluorescence decay of 4
F
3/2 energy levels is measured and analyzed. It is found that the fluorescence lifetime decreases first and then increases with the increasing dopant concentration due to the existing but finally weakening energy dissipation. As a result, a long radiation lifetime of about 191–444 μs is obtained at 1.06 μm in the prepared material. It is thus revealed that Nd3+-doped glass ceramic containing NaYF4 nanocrystallites is a potential candidate as a near-infrared laser material.
Influence of Coating Layer on Acoustic Wave Propagation in a Random Complex Medium with Resonant Scatterers*
Authors: Yang Hang , Zhang Xin , Guo Jian-hua , Wu Fu-gen , Yao Yuan-wei
Published: August 2019

We investigate the influence of coating layer on acoustic wave propagation in a dispersed random medium consisting of coated fibers. In the strong-scattering regime, the characteristics of wave scattering resonances are found to evolve regularly with the properties of the coating layer. By theoretical calculation, frequency gaps are found in acoustic excitation spectra in a random medium. The scattering cross section results present the evolution of scattering resonances with the properties of the coating layer, which offers a good explanation for the change of the frequency gaps. The velocity of the propagation quasi-mode is also shown to depend on the filling fraction of the coating layer. We use the generalized coherent potential-approximation approach to solve acoustic wave dispersion relations in a complicated random medium consisting of coating-structure scatterers. It is shown that our model reveals subtle changes in the behavior of the acoustic wave propagating quasi-modes.
Oscillation and Migration of Bubbles within Ultrasonic Field*
Authors: Wu Wen-Hua , Yang Peng-Fei , Zhai Wei , Wei Bing-Bo
Published: August 2019

The oscillation and migration of bubbles within an intensive ultrasonic field are important issues concerning acoustic cavitation in liquids. We establish a selection map of bubble oscillation mode related to initial bubble radius and driving sound pressure under 20 kHz ultrasound and analyze the individual-bubble migration induced by the combined effects of pressure gradient and acoustic streaming. Our results indicate that the pressure threshold of stable and transient cavitation decreases with the increasing initial bubble radius. At the pressure antinode, the Bjerknes force dominates the bubble migration, resulting in the large bubbles gathering toward antinode center, whereas small bubbles escape from antinode. By contrast, at the pressure node, the bubble migration is primarily controlled by acoustic streaming, which effectively weakens the bubble adhesion on the container walls, thereby enhancing the cavitation effect in the whole liquid.
Comparison of ITG and TEM Microturbulence in DIII–D Tokamak*
Authors: Hu Wei , Feng Hong-Ying , Zhang Wen-Lu
Published: August 2019

Microturbulence excited by ion temperature gradient (ITG)-dominant and trapped electron mode (TEM)-dominant instabilities is compared in the fusion plasmas using gyrokinetic simulations based on the realistic equilibrium data from DIII–D discharges. Collisions make a difference between two plasmas and give rise to similar results to those found in previous research experiments [Chin. Phys. Lett. 35 (2018) 105201]. The mode structures and frequency spectrum of the most unstable modes characterized by the ITG-dominant and TEM-dominant instabilities are excited in the lower and higher T
e
plasmas in the linear simulations. In the nonlinear simulations, contour plots of the perturbed potential are shown in the saturated stage, with the radial correlation lengths being microscopic on the order of the ion thermal gyroradius ρ
i
in both the ITG and the TEM microturbulences. The dominant mode wavelengths of the perturbed potential increase when evolving from linear to nonlinear stages in both simulations, with the fluctuation energy spreading from the linearly dominant modes to the nonlinearly dominant modes. The radial correlation lengths are about 4ρ
i
and the electron density fluctuation intensities are about 0.85% in the nonlinear saturated stage, which are in agreement with the experimental results.
Quasihole Tunneling in Disordered Fractional Quantum Hall Systems*
Authors: Lu Min , Jiang Na , Wan Xin
Published: August 2019

Fractional quantum Hall systems are often described by model wave functions, which are the ground states of pure systems with short-range interaction. A primary example is the Laughlin wave function, which supports Abelian quasiparticles with fractionalized charge. In the presence of disorder, the wave function of the ground state is expected to deviate from the Laughlin form. We study the disorder-driven collapse of the quantum Hall state by analyzing the evolution of the ground state and the single-quasihole state. In particular, we demonstrate that the quasihole tunneling amplitude can signal the fractional quantum Hall phase to insulator transition.
Fabrication and Characterization of GaN-Based Micro-LEDs on Silicon Substrate*
Authors: Wang Qi , Yu Jun-Chi , Tao Tao , Liu Bin , Zhi Ting , Cen Xu , Xie Zi-Li , Xiu Xiang-Qian , Zhou Yu-Gang , Zheng You-Dou , Zhang Rong
Published: August 2019

GaN-based micro light emitting diodes (micro-LEDs) on silicon (Si) substrates with 40 μm in diameter are developed utilizing standard photolithography and inductively coupled plasma etching techniques. From current-voltage curves, the relatively low turn-on voltage of 2.8 V and low reverse leakage current in the order of 10
−8
A/cm
2
indicate good electrical characteristics. As the injection current increases, the electroluminescence emission wavelength hardly shifts at around 433 nm, and the relative external quantum efficiency slightly decays, because the impact of quantum-confined Stark effect is not serious in violet-blue micro-LEDs. Since GaN-LEDs are cost effective on large-area Si and suitable for substrate transfer or vertical device structures, the fabricated micro-LEDs on Si should have promising applications in the fields of high-resolution display and optical communication.
Interlayer exchange coupling in (Ga,Mn)As ferromagnetic semiconductor multilayer systems
Authors: Lee Sanghoon , Chung Sunjae , Lee Hakjoon , Liu Xinyu , Dobrowolska M. , Furdyna J. K.
Published: August 2019

This paper describes interlayer exchange coupling (IEC) phenomena in ferromagnetic multilayer structures, focusing on the unique IEC features observed in ferromagnetic semiconductor (Ga,Mn)As-based systems. The dependence of IEC on the structural parameters, such as non-magnetic spacer thickness, number of magnetic layers, and carrier density in the systems has been investigated by using magnetotransport measurements. The samples in the series show both a typical anisotropic magnetoresistance (AMR) and giant magnetoresistance (GMR)-like effects indicating realization of both ferromagnetic (FM) and antiferromagnetic (AFM) IEC in (Ga,Mn)As-based multilayer structures. The results revealed that the presence of carriers in the non-magnetic spacer is an important factor to realize AFM IEC in this system. The studies further reveal that the IEC occurs over a much longer distance than predicted by current theories, strongly suggesting that the IEC in (Ga,Mn)As-based multilayers is a long-range interaction. Due to the long-range nature of IEC in the (Ga,Mn)As-based systems, the next nearest neighbor (NNN) IEC cannot be ignored and results in multi-step transitions during magnetization reversal that correspond to diverse spin configurations in the system. The strength of NNN IEC was experimentally determined by measuring minor loops that correspond to magnetization flips in specific (Ga,Mn)As layer in the multilayer system.
Progress on microscopic properties of diluted magnetic semiconductors by NMR and μSR
Authors: Gu Yilun , Guo Shengli , Ning Fanlong
Published: August 2019

Diluted magnetic semiconductors (DMSs) that possess both properties of semiconductors and ferromagnetism, have attracted a lot of attentions due to its potential applications for spin-sensitive electronic devices. Recently, a series of bulk form DMSs isostructural to iron-based superconductors have been reported, which can be readily investigated by microscopic experimental techniques such as nuclear magnetic resonance (NMR) and muon spin rotation (μSR). The measurements have demonstrated that homogeneous ferromagnetism is achieved in these DMSs. In this review article, we summarize experimental evidences from both NMR and μSR measurements. NMR results have shown that carriers facilitate the interactions between distant Mn atoms, while μSR results indicate that these bulk form DMSs and (Ga,Mn)As share a common mechanism for the ferromagnetic exchange interactions.
Two-dimensional ferromagnetic materials and related van der Waals heterostructures: a first-principle study
Authors: Zhai Baoxing , Du Juan , Li Xueping , Xia Congxin , Wei Zhongming
Published: August 2019

Since the successful fabrication of two-dimensional (2D) ferromagnetic (FM) monolayer CrI3 and Cr2Ge2Te6, 2D FM materials are becoming an exciting research topic in condensed matter physics and materials fields, as they provide a good platform to explore the fundamental physical properties of magnetic materials under 2D limit. In this review, we summarize the theoretical research progress of intrinsic 2D FM materials and related van der Waals heterostructures (vdWHs) including their electronic structures, magnetism, Curie temperature, valley polarization, and band alignment. Moreover, we also summarize recent researches on the methods that used to regulate the above properties of 2D FM materials and vdWHs, such as defects, doping, strain, electric field and interlayer coupling. These studies show that 2D FM materials have broad application prospects in spintronics and valleytronics. However, there are still many problems waiting to be solved on the way to practical application.
Decoding task engagement from distributed network electrophysiology in humans
Authors: Provenza Nicole R , Paulk Angelique C , Peled Noam , Restrepo Maria I , Cash Sydney S , Dougherty Darin D , Eskandar Emad N , Borton David A , Widge Alik S
Published: August 2019

Objective. Here, our objective was to develop a binary decoder to detect task engagement in humans during two distinct, conflict-based behavioral tasks. Effortful, goal-directed decision-making requires the coordinated action of multiple cognitive processes, including attention, working memory and action selection. That type of mental effort is often dysfunctional in mental disorders, e.g. when a patient attempts to overcome a depression or anxiety-driven habit but feels unable. If the onset of engagement in this type of focused mental activity could be reliably detected, decisional function might be augmented, e.g. through neurostimulation. However, there are no known algorithms for detecting task engagement with rapid time resolution. Approach. We defined a new network measure, fixed canonical correlation (FCCA), specifically suited for neural decoding applications. We extracted FCCA features from local field potential recordings in human volunteers to give a temporally continuous estimate of mental effort, defined by engagement in experimental conflict tasks. Main results. Using a small number of features per participant, we accurately decoded and distinguished task engagement from other mental activities. Further, the decoder distinguished between engagement in two different conflict-based tasks within seconds of their onset. Significance. These results demonstrate that network-level brain activity can detect specific types of mental efforts. This could form the basis of a responsive intervention strategy for decision-making deficits.
Photocatalytic degradation of methylene blue by TiO2/WO3-deoiled spent bleaching earth
Authors: Hindryawati N , Panggabean A S , N Subagyono RR D J , Sitinjak J Y
Published: August 2019

Degradation of methylene blue using pillared TiO2-WO3 onto deoiled spent bleaching earth (DSBE) has been conducted. Pillarization with TiO2-WO3 on DSBE using rarasaponin as surfactant. The structural and morphological of material has been carried out by X-ray fluorescence (XRF), and scanning electron microscopy coupled to the energy dispersive spectroscopy (SEM-EDX). Characterizations results show the increase composition of SiO2. The calcination result at 500°C show the TiO2-WO3 was deposited on the DSBE surface and suspected there is existence of Ti and W metals on the DSBE layer. The catalytic performance of TiO2-WO3/DSBE for photodegradation of methylene blue under visible light was 99.85 % within 30 minutes.
Antimicrobial assay of papaya seed ethanol extract (Carica papaya Linn) and phytochemical analysis of its active compounds
Authors: Masfufatun  , Yani N P W , Putri N P Y K
Published: August 2019

Natural drugs usage as alternative treatment has been increased in decades. This is due to the ‘back to nature’ life style of people and the side effect of natural drugs are relatively low. The prices of these natural drugs are cheaper as well. Papaya seed is one of the natural product with antimicrobial effect. The objectives of this research were to determine Minimum Inhibitory Concentration (MIC) of papaya seed ethanol extract to inhibit the growth of Candida albicans and Vibrio cholera and to analyze its active compounds. This research was performed using experimental design laboratory. The ethanol extract of papaya seed was obtained by maceration. The antimicrobial assay of papaya seed ethanol extract was performed using agar plate diffusion. The MIC determination of papaya seed ethanol extract was performed by 20, 15, 10, 5 and 1% concentration. The MIC of papaya seed ethanol extract against Candida albicans and Vibrio cholerae were in 5% concentration (diameter of inhibition zone=0.75 mm) and 15% (diameter of inhibition zone = 14.75 mm), respectively. The phytochemical assay of papaya seed ethanol extract showed there were alkaloids, flavonoids, steroids, polyphenols, tannins and saponins. It means that papaya seed ethanol extract has a good potential as antimicrobial therapy agent.