bluuebunny/crossref_metadata_2025 huggingface dataset:
Is a Single-Dose, Single-Agent Perioperative Antibiotic Protocol Adequate for Endoscopic Endonasal Skull Base Surgery? A 10-Year Review of 422 Cases
Authors: Hughes Mark A. , Phillips Nick , Tyagi Atul , Sheikh Asim , Sethi Kavita , Nix Paul
Published: July 2020

Objective Postoperative meningitis is a rare but potentially fatal complication of endoscopic endonasal skull base surgery. Prophylactic antibiotic use varies considerably worldwide. We sought to analyze the safety of a single-agent, single-dose protocol.

Design, Setting, and Participants A retrospective review of 422 procedures performed during 404 admission episodes from 2009 to 2019, encompassing sella, parasella, and other anterior skull base pathologies.

Main Outcome Measures Primary outcome measure was development of meningitis within 30 days of surgery. Additional information collected: underlying pathological diagnosis, intraoperative cerebrospinal fluid (CSF) leak, postoperative CSF leak, and primary or revision surgery.

Results Of 404 admission episodes for endoscopic anterior skull base surgery, 12 cases developed meningitis. Seven had positive CSF cultures and all 12 recovered. For pathology centered on the sella (including pituitary adenoma), the rate of meningitis was 1.1% (3/283). For pathologies demanding an extended approach (including meningioma and craniopharyngioma), the rate of meningitis was 14.5% (9/62). Postoperative CSF leak requiring surgical repair increased the relative risk by 37-fold. There were no cases of meningitis following repair of long-standing CSF fistula or encephalocoele (0/26) and no cases following surgery for sinonasal tumors with skull base involvement (0/33).

Conclusion For sella-centered pathologies, a single dose of intravenous co-amoxiclav (or teicoplanin) is associated with rates of meningitis comparable to those reported in the literature. Postoperative meningitis was significantly higher for extended, intradural transphenoidal approaches, especially when postoperative CSF leak occurred. Fastidious efforts to prevent postoperative CSF leak are crucial to minimizing risk of meningitis.
Measuring social response to different journalistic techniques on Facebook
Authors: Schmidt Ana L. , Peruzzi Antonio , Scala Antonio , Cinelli Matteo , Pomerantsev Peter , Applebaum Anne , Gaston Sophia , Fusi Nicole , Peterson Zachary , Severgnini Giuseppe , De Cesco Andrea F. , Casati Davide , Novak Petra Kralj , Stanley H. Eugene , Zollo Fabiana , Quattrociocchi Walter
Published: July 2020

Recent studies have shown that online users tend to select information that adheres to their system of beliefs, ignore information that does not, and join groups that share a common narrative. This information environment can elicit tribalism instead of informed debate, especially when issues are controversial. Algorithmic solutions, fact-checking initiatives, and many other approaches have shown limitations in dealing with this phenomenon, and heated debate and polarization still play a pivotal role in online social dynamics (e.g. traditional vs. anti-establishment polarization). To understand the effect of different communication strategies able to smooth polarization, in this paper, together with Corriere della Sera, a major Italian news outlet, we measure the social response of users to different types of news framing. We analyse users’ reactions to 113 ad-hoc articles published on the newspaper’s Facebook page and the corresponding news articles on the topic of migration, published from March to December 2018. We examine different journalistic techniques and content types by analyzing their impact on user comments in terms of toxicity, criticism of the newspaper, and stance concerning migration. We find that visual pieces and factual news reports elicit the highest level of trust in the media source, while opinion pieces and editorials are more likely to be criticized. We also notice that data-driven pieces elicit an extremely low level of trust in the news source. Furthermore, coherently with the echo chambers behaviour, we find social conformity strongly affecting the commenting behaviour of users on Facebook.
Geometric phases for finite-dimensional systems—The roles of Bargmann invariants, null phase curves, and the Schwinger–Majorana SU(2) framework
Authors: Akhilesh K. S. , Arvind  , Chaturvedi S. , Mallesh K. S. , Mukunda N.
Published: July 2020

We present a study of the properties of Bargmann Invariants (BIs) and Null Phase Curves (NPCs) in the theory of the geometric phase for finite dimensional systems. A recent suggestion to exploit the Majorana theorem on symmetric SU(2) multispinors is combined with the Schwinger oscillator operator construction to develop efficient operator-based methods to handle these problems. The BI is described using intrinsic unitary invariant angle parameters whose algebraic properties as functions of Hilbert space dimension are analyzed using elegant group theoretic methods. The BI-geometric phase connection, extended by the use of NPCs, is explored in detail, and interesting new experiments in this subject are pointed out.
Stiffness based enrichment of leukemia cells using microfluidics
Authors: Islam Muhymin , Raj Abhishek , McFarland Brynn , Brink Hannah Maxine , Ciciliano Jordan , Fay Meredith , Myers David Richard , Flowers Christopher , Waller Edmund K. , Lam Wilbur , Alexeev Alexander , Sulchek Todd
Published: July 2020

To improve the survival rate of cancer patients, new diagnosis strategies are necessary to detect lower levels of cancer cells before and after treatment regimens. The scarcity of diseased cells, particularly in residual disease after treatment, demands highly sensitive detection approaches or the ability to enrich the diseased cells in relation to normal cells. We report a label-free microfluidic approach to enrich leukemia cells from healthy cells using inherent differences in cell biophysical properties. The microfluidic device consists of a channel with an array of diagonal ridges that recurrently compress and translate flowing cells in proportion to cell stiffness. Using devices optimized for acute T cell leukemia model Jurkat, the stiffer white blood cells were translated orthogonally to the channel length, while softer leukemia cells followed hydrodynamic flow. The device enriched Jurkat leukemia cells from white blood cells with an enrichment factor of over 760. The sensitivity, specificity, and accuracy of the device were found to be >0.8. The values of sensitivity and specificity could be adjusted by selecting one or multiple outlets for analysis. We demonstrate that low levels of Jurkat leukemia cells (1 in 104 white blood cells) could be more quickly detected using flow cytometry by using the stiffness sorting pre-enrichment. In a second mode of operation, the device was implemented to sort resistive leukemia cells from both drug-sensitive leukemia cells and normal white blood cells. Therefore, microfluidic biomechanical sorting can be a useful tool to enrich leukemia cells that may improve downstream analyses.
Correcting anisotropic intensity in light sheet images using dehazing and image morphology
Authors: Teranikar Tanveer , Messerschmidt Victoria , Lim Jessica , Bailey Zach , Chiao Jung-Chih , Cao Hung , Liu Jiandong , Lee Juhyun
Published: July 2020

Light-sheet fluorescence microscopy (LSFM) provides access to multi-dimensional and multi-scale in vivo imaging of animal models with highly coherent volumetric reconstruction of the tissue morphology, via a focused laser light sheet. The orthogonal illumination and detection LSFM pathways account for minimal photobleaching and deep tissue optical sectioning through different perspective views. Although rotation of the sample and deep tissue scanning constitutes major advantages of LSFM, images may suffer from intrinsic problems within the modality, such as light mismatch of refractive indices between the sample and mounting media and varying quantum efficiency across different depths. To overcome these challenges, we hereby introduce an illumination correction technique integrated with depth detail amelioration to achieve symmetric contrast in large field-of-view images acquired using a low power objective lens. Due to an increase in angular dispersion of emitted light flux with the depth, we combined the dehazing algorithm with morphological operations to enhance poorly separated overlapping structures with subdued intensity. The proposed method was tested on different LSFM modalities to illustrate its applicability on correcting anisotropic illumination affecting the volumetric reconstruction of the fluorescently tagged region of interest.
Observation of the kinetic buildup of x-ray conduction current in ZnSe crystals
Authors: Alizadeh M. , Degoda V. Ya. , Podust G. P. , Pavlova N. Yu.
Published: July 2020

We have been observing the kinetic buildup of electrical conduction current upon x-ray irradiation in ZnSe single crystals. The objective is to understand the behavior of ZnSe crystals under x-ray irradiation, toward their potential use in x-ray detectors that do not require cooling and can operate above room temperature. The paper focuses on the factors that affect the behavior of traps at room temperature. A model is developed to understand the origin of the behavior of the conduction current under x-ray irradiation, taking into account the contributions from three types of traps for electrons (shallow, phosphorescent, and deep) and two luminescence centers (luminescence bands of 630 and 970 nm). Principally, the model is applied to the fitting of the experimental curves. Consequently, the work puts in evidence the role of electron accumulation on traps on the x-ray conduction current buildup on ZnSe crystals. We have obtained experimental dependencies of x-ray conduction current buildup current at 85 K, which indicates the presence of delay in comparison with x-ray luminescence buildup. This paper will demonstrate the effectiveness of our theoretical method in the framework of the multi-center model for wide-gap semiconductors.
Measurements of a 2.1 MeV H− beam with an Allison scanner
Authors: Richard C. , Alvarez M. , Carneiro J. P. , Hanna B. , Prost L. , Saini A. , Scarpine V. , Shemyakin A.
Published: July 2020

Transverse 2D phase space distributions of a 2.1 MeV, 5 mA H− beam are measured at the Proton Improvement Plan II Injector Test accelerator at Fermilab with an Allison scanner. This paper describes the design, calibration, and performance of the scanner along with the main results from beam measurements. Analyses of the recorded phase portraits are performed primarily in action-phase coordinates. The stability of the action under linear optics makes it easier to compare measurements taken under different beamline conditions. The amplitude of a single measured point (“pixel”) is proportional to the phase density in the corresponding portion of the beam. When the Twiss parameters are calculated using only the high-phase density part of the beam, the pixel amplitude in the beam core is found to be decreasing approximately exponentially with action and to be phase-independent. Outside of the core, the amplitudes decrease with action at a slower rate than in the core. This “tail” comprises 10%–30% of the beam, with 0.1% of the total measured intensity extending beyond action 10–20 times larger than the rms emittance. The transition from the core to the tail is accompanied by the appearance of two “branches” that are separated in phase and extend beyond the core. A set of selected measurements shows that there is no measurable emittance dilution along the beamline; the beam parameters are practically constant over a 0.5 ms pulse; and scraping in various parts of the beamline is an effective way to decrease the transverse tails by removing the branches.
Mapping regulators of cell fate determination: Approaches and challenges
Authors: Kumar Aditya , Mali Prashant
Published: July 2020

Given the limited regenerative capacities of most organs, strategies are needed to efficiently generate large numbers of parenchymal cells capable of integration into the diseased organ. Although it was initially thought that terminally differentiated cells lacked the ability to transdifferentiate, it has since been shown that cellular reprogramming of stromal cells to parenchymal cells through direct lineage conversion holds great potential for the replacement of post-mitotic parenchymal cells lost to disease. To this end, an assortment of genetic, chemical, and mechanical cues have been identified to reprogram cells to different lineages both in vitro and in vivo. However, some key challenges persist that limit broader applications of reprogramming technologies. These include: (1) low reprogramming efficiencies; (2) incomplete functional maturation of derived cells; and (3) difficulty in determining the typically multi-factor combinatorial recipes required for successful transdifferentiation. To improve efficiency by comprehensively identifying factors that regulate cell fate, large scale genetic and chemical screening methods have thus been utilized. Here, we provide an overview of the underlying concept of cell reprogramming as well as the rationale, considerations, and limitations of high throughput screening methods. We next follow with a summary of unique hits that have been identified by high throughput screens to induce reprogramming to various parenchymal lineages. Finally, we discuss future directions of applying this technology toward human disease biology via disease modeling, drug screening, and regenerative medicine.
Influence of viscoelasticity on mixing performance of primary and secondary circulation flows in stirred vessels
Authors: Hara S. , Ebihara S. , Kawaguchi Y.
Published: July 2020

The aim of this study was to experimentally verify the mixing performance of primary and secondary circulation flows appearing in turbulence in stirred vessels of Newtonian and viscoelastic fluids. Impeller torque measurements, flow visualization, and particle image velocimetry and planar laser-induced fluorescence measurements were performed. In the case of the Newtonian fluid, a tornado-like flow that was a combination of primary and secondary circulation flows was observed with small-scale turbulent eddies. This flow required a moderate torque power and shortened the mixing time. Conversely, a large-scale primary circulation flow of a slow rigid vortex with no small-scale turbulent eddies was observed in the viscoelastic fluid. Although the discharge flow was enhanced or diminished dependently on the Reynolds number and surfactant concentration, it induced slow large-scale secondary circulation flows in the stirred vessel. As a result, the tornado-like flow disappeared, and these flows resulted in a long time constant of the mixing. Even with such flow characteristics, while the low-concentration case indicates that a low torque corresponding to the driving power is needed to drive the flow, the high-concentration case suggests that the high torque is due to the occurrence of additional viscoelastic stress.
Voltage-gated ion channels mediate the electrotaxis of glioblastoma cells in a hybrid PMMA/PDMS microdevice
Authors: Tsai Hsieh-Fu , IJspeert Camilo , Shen Amy Q.
Published: July 2020

Transformed astrocytes in the most aggressive form cause glioblastoma, the most common cancer in the central nervous system with high mortality. The physiological electric field by neuronal local field potentials and tissue polarity may guide the infiltration of glioblastoma cells through the electrotaxis process. However, microenvironments with multiplex gradients are difficult to create. In this work, we have developed a hybrid microfluidic platform to study glioblastoma electrotaxis in controlled microenvironments with high throughput quantitative analysis by machine learning-powered single cell tracking software. By equalizing the hydrostatic pressure difference between inlets and outlets of the microchannel, uniform single cells can be seeded reliably inside the microdevice. The electrotaxis of two glioblastoma models, T98G and U-251MG, requires an optimal laminin-containing extracellular matrix and exhibits opposite directional and electro-alignment tendencies. Calcium signaling is a key contributor in glioblastoma pathophysiology but its role in glioblastoma electrotaxis is still an open question. Anodal T98G electrotaxis and cathodal U-251MG electrotaxis require the presence of extracellular calcium cations. U-251MG electrotaxis is dependent on the P/Q-type voltage-gated calcium channel (VGCC) and T98G is dependent on the R-type VGCC. U-251MG electrotaxis and T98G electrotaxis are also mediated by A-type (rapidly inactivating) voltage-gated potassium channels and acid-sensing sodium channels. The involvement of multiple ion channels suggests that the glioblastoma electrotaxis is complex and patient-specific ion channel expression can be critical to develop personalized therapeutics to fight against cancer metastasis. The hybrid microfluidic design and machine learning-powered single cell analysis provide a simple and flexible platform for quantitative investigation of complicated biological systems.
An integrable (classical and quantum) four-wave mixing Hamiltonian system
Authors: Odzijewicz A. , Wawreniuk E.
Published: July 2020

A four-wave mixing Hamiltonian system on the classical as well as on the quantum level is investigated. In the classical case, if one assumes the frequency resonance condition of the form ω0 − ω1 + ω2 − ω3 = 0, this Hamiltonian system is integrated in quadratures, and the explicit formulas of solutions are presented. Under the same condition, the spectral decomposition of quantum Hamiltonian is found, and thus, the Heisenberg equation for this system is solved. Some applications of the obtained results in non-linear optics are discussed.
W2020: A Database of Validated Rovibrational Experimental Transitions and Empirical Energy Levels of H216O
Authors: Furtenbacher Tibor , Tóbiás Roland , Tennyson Jonathan , Polyansky Oleg L. , Császár Attila G.
Published: July 2020

A detailed understanding of the complex rotation–vibration spectrum of the water molecule is vital for many areas of scientific and human activity, and thus, it is well studied in a number of spectral regions. To enhance our perception of the spectrum of the parent water isotopologue, H216O, a dataset of 270 745 non-redundant measured transitions is assembled, analyzed, and validated, yielding 19 204 rovibrational energy levels with statistically reliable uncertainties. The present study extends considerably an analysis of the rovibrational spectrum of H216O, published in 2013, by employing an improved methodology, considering about one-third more new observations (often with greatly decreased uncertainties), and using a highly accurate first-principles energy list for validation purposes. The database of experimental rovibrational transitions and empirical energy levels of H216O created during this study is called W2020. Some of the new transitions in W2020 allow the improved treatment of many parts of the dataset, especially considering the uncertainties of the experimental line positions and the empirical energy values. The W2020 dataset is examined to assess where measurements are still lacking even for this most thoroughly studied isotopologue of water, and to provide definitive energies for the lower and upper states of many yet-to-be-measured transitions. The W2020 dataset allows the evaluation of several previous compilations of spectroscopic data of water and the accuracy of previous effective Hamiltonian fits.
Modeling the dependence of the negative corona current density on applied voltage rise time
Authors: Saleh Dawood N. , Algwari Qais Th. , Amouri Farook Kh.
Published: July 2020

In this paper, a numerical simulation is used to investigate the influence of applied voltage rise time on negative corona current characteristics in SF6 at atmospheric pressure. There were 23 particle species and 67 kinds of reactions considered in plasma chemical reactions. The influence of different rise times of the applied voltage is investigated. The spatial distributions of the radial electric field and total density of electrons and positive and negative ions, at and after the inception time of the corona current pulse, are used to explain the role of the rise time of the applied voltage on the mechanism of corona current pulse formation. It is found that the corona inception time, inception voltage, peak value of current pulse, number of sub-current pulses, and the time between the sub-pulses are strongly affected by the movement of negative ion clouds produced by the attachment. The quantitative analysis of the negative ions shows that the light ions preceded the heavy ions in their motion far away from the cathode and that this motion is governed by the rise time of the applied voltage.
Liquid jet disintegration memory effect on downstream spray fluctuations in a coaxial twin-fluid injector
Authors: Kumar Abhijeet , Sahu Srikrishna
Published: July 2020

This paper intends to investigate the influence of unsteadiness in the liquid jet disintegration process on downstream fluctuations of spray characteristics in a coaxial twin-fluid injector. Time-resolved high-speed shadowgraphic imaging of the spray was obtained for different axial locations downstream of the injector exit at z = 0, 8Dl, and 30Dl, where Dl is the central liquid tube diameter. The primary jet breakup unsteadiness close to the injector exit was characterized by measuring both shear-driven Kelvin–Helmholtz (KH) instability and flapping instability in addition to jet breakup length fluctuations. Downstream of the liquid jet core region, the liquid shedding rate (fshed) was measured at z = 8Dl. The power spectrum of time series data of instantaneous volume mean diameter (VMD) measured at z = 30Dl indicated periodic variation of the droplet size. The corresponding frequency (fVMD) was obtained. It was found that for lower range of gas-to-liquid momentum flux ratio (M < 4), both fshed and fVMD are larger than the frequency of KH instability. Also, for such conditions, larger temporal variation of the droplet size is realized, and this leads to higher fluctuations of the local liquid mass flux. Proper orthogonal decomposition analysis of the shadowgraph images for different axial locations identified similar topology of the dominant mode that corresponds to flapping instability. The results suggest that even far downstream of the injector exit, some memory of the upstream unsteady jet breakup process is retained, which strongly influences spatio-temporal evolution of droplet characteristics, thereby contributing to local spray fluctuations.
Finite-temperature many-body perturbation theory in the grand canonical ensemble
Authors: Hirata So , Jha Punit K.
Published: July 2020

A finite-temperature many-body perturbation theory is presented, which expands in power series the electronic grand potential, chemical potential, internal energy, and entropy on an equal footing. Sum-over-states and sum-over-orbitals analytical formulas for the second-order perturbation corrections to these thermodynamic properties are obtained in a time-independent, nondiagrammatic, algebraic derivation, relying on the sum rules of the Hirschfelder–Certain degenerate perturbation energies in a degenerate subspace as well as nine algebraic identities for the zeroth-order thermal averages of one- through four-indexed quantities and products thereof. They reproduce numerically exactly the benchmark data obtained as the numerical derivatives of the thermal-full-configuration-interaction results for a wide range of temperatures.
Tip-enhanced Raman spectroscopy: Chemical analysis with nanoscale to angstrom scale resolution
Authors: Mahapatra Sayantan , Li Linfei , Schultz Jeremy F. , Jiang Nan
Published: July 2020

Tip-enhanced Raman spectroscopy (TERS), a cutting-edge near-field spectroscopic tool, provides invaluable chemical insight with impressive spatial resolution in chemistry-related fields such as molecular and catalytic systems, surface science, two-dimensional materials, and biochemistry. High-resolution TERS, in particular, which has advanced exceptionally in the last five years, provides a unique opportunity to scrutinize single molecules individually. Here, this perspective places emphasis on the basic concepts and recent experimental findings of this state-of-the-art research and concludes with a glimpse of future prospects.
Red light-inducible overall water-splitting photocatalyst, gold-inserted zinc rhodium oxide and bismuth vanadium oxide heterojunction, connected using gold prepared by sputtering in ionic liquid
Authors: Yoda Masaomi , Takashima Toshihiro , Akiyoshi Kazutaka , Torimoto Tsukasa , Irie Hiroshi
Published: July 2020

We prepared a solid-state Z-scheme photocatalyst in which zinc rhodium oxide (ZnRh2O4) and bismuth vanadium oxide (Bi4V2O11) that served as hydrogen (H2) and oxygen (O2) evolution photocatalysts, respectively, were connected with gold (Au) nanoparticles. The Au nanoparticles were prepared by sputtering in an ionic liquid, N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide, to generate Au/ZnRh2O4/Au/Bi4V2O11 with various amounts of Au in the 12 mol. %–29 mol. % range (vs 1.0 mol ZnRh2O4 + 0.2 mol Bi4V2O11). Au/ZnRh2O4/Au/Bi4V2O11 photocatalyzed overall pure-water splitting under irradiation with red light at a wavelength of 700 nm, and the dependence of the amounts of Au on the apparent quantum efficiency tended to increase in the measurement range.
Numerical simulations for mixed convective hydromagnetic peristaltic flow in a curved channel with joule heating features
Authors: Ahmed Raheel , Ali Nasir , Khan Sami Ullah , Tlili Iskander
Published: July 2020

This article investigates the flow and mass transportation characteristics in the peristaltic motion configured by a heated curved channel. The coupling between momentum and energy equation is achieved using the Boussinesq approximation. The equations describing the flow and heat/mass transfer are developed using curvilinear coordinates. A reduction of these equations is made based on the lubrication approximation. The reduced linear ordinary differential equations are integrated numerically using an implicit finite difference scheme. The effects of thermal and concentration Grashof numbers, Hartmann number, Brinkmann number, and curvature parameter on longitudinal velocity, pressure rise, temperature, and mass concentration are analyzed in detail. It is found that the temperature field is enhanced with an increase in the thermal Grashof number and Hartmann number, while the mass concentration decreases with an increase in the thermal Grashof number and Hartmann number. The flow patterns in the channel illustrating the effects of Grashof numbers, Brinkmann number, and Hartmann number are also displayed. It is observed that flow movements become intense for greater values of Brinkman number, thermal Grashof number, and Hartmann number.
An extended moments model of quantum efficiency for metals and semiconductors
Authors: Jensen Kevin L. , Shabaev Andrew , Lambrakos Samuel G. , Finkenstadt Daniel , Petillo John J. , Alexander Anna M. , Smedley John , Moody Nathan A. , Yamaguchi Hisato , Liu Fangze , Neukirch Amanda J. , Tretiak Sergei
Published: July 2020

The complexity of photocathode designs and detector materials, and the need to model their performance for short pulse durations, the response to high-frequency photons, the presence of coatings and/or thinness of the absorptive layer, necessitates modifications to three-step and moments models of photoemission that are used in simulation codes. In this study, methods to include input from computationally intensive approaches, such as density functional theory to model optical properties and transfer matrix approaches to treat emission from the surface or transport past coatings, by means of parametric models are demonstrated. First, a technique to accurately represent optical behavior so as to model reflectivity and penetration depth is given. Second, modifications to bulk models arising from the usage of thin film architectures, and a means to rapidly calculate them, are provided. Third, a parameterization to model the impact of wells associated with coatings and surface layers on the transmission probably is given. In all cases, the methods are computationally efficient and designed to allow for including input from numerically intensive approaches that would otherwise be unavailable for simulations.
Hydration free energies from kernel-based machine learning: Compound-database bias
Authors: Rauer Clemens , Bereau Tristan
Published: July 2020

We consider the prediction of a basic thermodynamic property—hydration free energies—across a large subset of the chemical space of small organic molecules. Our in silico study is based on computer simulations at the atomistic level with implicit solvent. We report on a kernel-based machine learning approach that is inspired by recent work in learning electronic properties but differs in key aspects: The representation is averaged over several conformers to account for the statistical ensemble. We also include an atomic-decomposition ansatz, which offers significant added transferability compared to molecular learning. Finally, we explore the existence of severe biases from databases of experimental compounds. By performing a combination of dimensionality reduction and cross-learning models, we show that the rate of learning depends significantly on the breadth and variety of the training dataset. Our study highlights the dangers of fitting machine-learning models to databases of a narrow chemical range.
Nonlinear study of tearing modes and plasma flows around magnetic islands in tokamak plasmas
Authors: Yang Jizong , Li Jingchun , Dong Jiaqi , Liu Songfen , Shi Peng , Zhao Yizhen , Chen Shaoyong
Published: July 2020

The behavior of non-linear tearing modes and the plasma flows around magnetic islands is studied numerically in a cylindrical geometry using the method of reduced magneto-hydro-dynamic simulation. The results show that the single tearing mode (STM) becomes stable in a short time. The magnetic islands of double tearing modes (DTMs) first develop to a sufficiently large scale and then couple together when entering the non-linear phase. It is also shown that, before the non-linear growth stage, the perturbed kinetic energy and magnetic energy of both the STM and DTM have a process from different signs to constant positive values. For the STM island and plasma flow, it is demonstrated that the shear flow is formed on both sides of the islands and the poloidal flow velocity around the O-point is larger than that around the X-point. For the DTM island and plasma flow, we found that the peak of the poloidal flow velocity is mainly distributed at the O-point edge and the X-point of the magnetic island and the plasma flow velocities at the magnetic island edges are opposite. In addition, the process of plasma flow accompanying the nonlinear evolution of tearing modes is also presented.
Quasi-one-dimensional Sb2(S,Se)3 alloys as bandgap-tunable and defect-tolerant photocatalytic semiconductors
Authors: Huang Menglin , Cai Zenghua , Chen Shiyou
Published: July 2020

Both Sb2S3 and Sb2Se3 have been studied as promising photocatalytic and photovoltaic semiconductors because of their suitable bandgaps, high light absorption coefficients and good stability. Through forming the mixed-anion Sb2(S,Se)3 alloys, the bandgaps and lattice parameters can be tuned and a band structure engineering design of semiconductor heterostructures becomes possible. However, the properties of the disordered Sb2(S,Se)3 alloys are currently not clear. Using first-principles calculations, we show that the alloys are highly miscible with low formation enthalpies, so composition-variable and uniform alloys can be fabricated under room temperature. The bandgaps of the alloys change almost linearly as the alloy composition (S/Se ratio) varies, indicating that the bandgap engineering can be quite flexible. The calculations of the defect properties show that there are dozens of detrimental defects producing deep levels in the bandgap of the alloy under the Sb-rich (Se-poor) condition, which can cause serious electron–hole non-radiative recombination and limit the minority carrier lifetime. The formation of these detrimental defects can be largely suppressed under the Sb-poor condition, so we propose that the Sb-poor (Se-rich) condition should be adopted for fabricating Sb2(S,Se)3 alloys as photocatalytic and photovoltaic light-absorber semiconductors with long minority carrier lifetimes.
A five degrees-of-freedom errors measurement system for rotary axis with reference laser for reference axis alignment
Authors: Liu Li , Lou Zhi-Feng , Huang Yu-Bin , Fan Kuang-Chao , Zhang Ji-Yun
Published: July 2020

This paper proposes a five degrees-of-freedom measurement system for measuring geometric errors of the rotary axis. To align the measured rotary axis with the reference axis, a diode laser is used to represent the rotary axis of the measured rotation stage. Based on the proposed measurement system, a model for separating the position independent geometric errors and position dependent geometric errors of the measured rotary axis from the measured value is established and verified by measurement experiments. The results of measurement experiments repeated for five times show that the measurement uncertainty of the proposed measurement system is less than ±1.6 µm for radial motion, the measurement uncertainty is less than ±1.7 arc sec for tilt motion, and the measurement uncertainty is less than ±1.3 arc sec for angle position.
Cathodoluminescence of organo-lanthanide complexes
Authors: Kukinov A. A. , Balashova T. V. , Kaverin B. S. , Ilichev V. A. , Obolensky S. V. , Trufanov A. N. , Bochkarev M. N.
Published: July 2020

The cathodoluminescence (CL) of organo-lanthanide complexes is studied as a modeling of beta luminescence. It is found that complexes of Sc, La, and lanthanides with anionic ÔO, ÔN bidentate and O-monodentate ligands under excitation by fast electrons display luminescence of various intensities. In the spectra of Sc, La, Nd, Er, and Tm compounds, only broadened bands of the ligands peaked about 450 nm are observed. A similar spectrum gives anthracene, which is used as a reference compound. In contrast, the emission spectra of Eu and Tb compounds contain only the narrow bands of f–f transitions characteristic of these metals. The spectra of Sm, Dy, and Yb derivatives exhibit both the bands of ligands and weak metal-centered luminescence. X-ray luminescence (RL) of several terbium complexes is also investigated. A comparison of the photoluminescence, CL and RL spectra of the studied compounds reveals a similarity of the shape of the spectra but a significant difference in their intensities. Terbium compounds show record scintillating activity. Possible mechanisms of luminescence of organo-lanthanide complexes upon different types of excitation are discussed.
The physics of lipidic mesophase delivery systems
Authors: Aleandri Simone , Mezzenga Raffaele
Published: July 2020

Effectively releasing drugs in the body depends on the physical and chemical traits of a special class of liquid crystals.
Phytoplankton in dryland riverine waterholes: environmental drivers, variability and ecosystem-monitoring potential using different levels of taxonomic resolution and dataset reduction
Authors: Preite Carrie K. , Pearson Richard G.
Published: July 2020

Waterholes that remain in the dry season in intermittent dryland rivers are important biotic refugia, but detailed ecological descriptions of these habitats and their plankton are scarce. We aimed to determine spatial and temporal variation in phytoplankton assemblages in a tropical Australian dryland river system, their main environmental determinants and the potential of the phytoplankton for ecosystem monitoring. We sampled nine sites in three rivers over 2 years using standard methods. Water quality and phytoplankton assemblages varied considerably among sites, rivers and seasons, reflecting lithology, hydrology, bathymetry and local catchment influences. Major environmental drivers included conductivity, pH, temperature and species of N and P. We analysed several derived versions of the original dataset by using density and presence–absence data, eliminating rarer species and grouping species into higher taxa. We found substantial consistency among analyses in environmental drivers, identified using distance-based linear modelling, and in variability among systems, identified using nested permutational multivariate analysis of variance (PERMANOVA). Responsiveness of the algal assemblages to environmental drivers and consistency among analyses, even using subsamples at low taxonomic resolution, suggests potential for ecosystem monitoring and optimising of sample throughput, although variability among systems requires substantial effort to determine the range of reference conditions.
Cofactor-enabled functional expression of fruit fly, honeybee, and bumblebee nicotinic receptors reveals picomolar neonicotinoid actions
Authors: Ihara Makoto , Furutani Shogo , Shigetou Sho , Shimada Shota , Niki Kunihiro , Komori Yuma , Kamiya Masaki , Koizumi Wataru , Magara Leo , Hikida Mai , Noguchi Akira , Okuhara Daiki , Yoshinari Yuto , Kondo Shu , Tanimoto Hiromu , Niwa Ryusuke , Sattelle David B. , Matsuda Kazuhiko
Published: July 2020

Significance

Neonicotinoids acting on insect nicotinic acetylcholine receptors (nAChRs) are deployed for crop protection, but growing evidence for adverse effects on insect pollinators has led to restricted use of some neonicotinoids in the EU. It is therefore vital to understand the target site actions of neonicotinoids in pollinators, but to date the difficulties of heterologous expression of insect nAChRs have hampered progress. We have found that a thioredoxin (TMX3) enables robust functional expression of honeybee, bumblebee, and fruit fly nAChRs in
Xenopus laevis
oocytes. With this advance, we show that expressed bee nAChRs are more neonicotinoid-sensitive than those of fruit fly, and clothianidin can modulate both honeybee and bumblebee nAChRs at a concentration below that commonly observed in agricultural fields.
CDKD-dependent activation of CDKA;1 controls microtubule dynamics and cytokinesis during meiosis
Authors: Sofroni Kostika , Takatsuka Hirotomo , Yang Chao , Dissmeyer Nico , Komaki Shinichiro , Hamamura Yuki , Böttger Lev , Umeda Masaaki , Schnittger Arp
Published: July 2020

Precise control of cytoskeleton dynamics and its tight coordination with chromosomal events are key to cell division. This is exemplified by formation of the spindle and execution of cytokinesis after nuclear division. Here, we reveal that the central cell cycle regulator CYCLIN DEPENDENT KINASE A;1 (CDKA;1), the Arabidopsis homologue of Cdk1 and Cdk2, partially in conjunction with CYCLIN B3;1 (CYCB3;1), is a key regulator of the microtubule cytoskeleton in meiosis. For full CDKA;1 activity, the function of three redundantly acting CDK-activating kinases (CAKs), CDKD;1, CDKD;2, and CDKD;3, is necessary. Progressive loss of these genes in combination with a weak loss-of-function mutant in CDKA;1 allowed a fine-grained dissection of the requirement of cell-cycle kinase activity for meiosis. Notably, a moderate reduction of CDKA;1 activity converts the simultaneous cytokinesis in Arabidopsis, i.e., one cytokinesis separating all four meiotic products concurrently into two successive cytokineses with cell wall formation after the first and second meiotic division, as found in many monocotyledonous species.
Generating multi-partite entanglement from the quantum vacuum with a finite-lifetime mirror
Authors: Foo Joshua , Onoe Sho , Zych Magdalena , Ralph Timothy C
Published: July 2020

Observers following special classes of finite-lifetime trajectories have been shown to experience an effective temperature, a generalisation of the Unruh temperature for uniformly accelerated observers. We consider a mirror following such a trajectory—and is hence localised to a strictly bounded causal diamond—that perfectly reflects incoming field modes. We find that inertial observers in the Minkowski vacuum detect particles along the half null-rays at the beginning and end of the mirror’s lifetime. These particle distributions exhibit multi-partite entanglement, which reveals novel structure within the vacuum correlations. The interaction is modelled using a non-perturbative circuit model and does not suffer from energy divergences.
An adaptive solution to the chemical master equation using quantized tensor trains with sliding windows
Authors: Dinh Trang , Sidje Roger B
Published: July 2020

To cope with an extremely large or even infinite state space when solving the chemical master equation in biological problems, a potent strategy is to restrict to a finite state projection (FSP) and represent the transition matrix and probability vector in quantized tensor train (QTT) format, leading to savings in storage while retaining accuracy. In an earlier adaptive FSP–QTT algorithm, the multidimensional state space was downsized and kept in the form of a hyper rectangle that was updated when needed by selectively doubling some of its side dimensions. However, this could result in a much larger state space than necessary, with the effect of hampering both the execution time and stepping scheme. In this work, we improve the algorithm by enabling sliding windows that can dynamically slide, shrink or expand, with updates driven by a number of stochastic simulation algorithm trajectories. The ensuing state space is a considerably reduced hyper rectangle containing only the most probable states at each time step. Three numerical experiments of varying difficulty are performed to compare our approach with the original adaptive FSP–QTT algorithm.
Key drivers of the rebound trend of China’s CO2 emissions
Authors: Zhang Yaxin , Zheng Xinzhu , Cai Wenjia , Liu Yuan , Luo Huilin , Guo Kaidi , Bu Chujie , Li Jin , Wang Can
Published: July 2020

China’s CO2 emissions declined by 5.1% in 2013–2016 as China steps into a new period of development, in which the economy shifts from the previous high-speed growth driven by input and investment to a medium-speed growth driven by innovation and consumption. However, the decline did not continue; the national CO2 emissions rebounded since 2016, with the drivers of the rebound unclear. Here, we apply the input–output structure decomposition analysis to decompose emissions in 2002–2017 to reveal driving factors of the emission rebound trend. Results show that the input–output structure among sectors (partially reflecting production structure) and the demand pattern have contributed to emission reduction as China entering ‘the new normal’ pattern of development. However, the two factors reversed and therefore induced emissions, contributing to 5.2% and 0.1% of the increase in emissions since 2015. Such obvious contribution reversal can be explained as a new round of infrastructure stimulated substantial energy consumption and the electricity demand was mainly supported by coal-fired power (59.0%). Besides, the emission reduction effect of the energy mix has shrunk from −11.8% in 2012–2015 to −6.9% in 2015–2017, closely related to the slowing growth of renewable energy and the slight recovery of coal consumption. The findings can reasonably infer novel insights into curbing the potential reversal of China’s emission trend and aligning China’s CO2 emission trend with the goal of achieving peak emissions before 2030.
Analysis of the tree stands health status in the near border area of Russia and Finland based on the regular grid of sample plots and GIS-technologies
Authors: Alekseev A , Vetrov L , Gurjanov M , Nikiforchin I , Chernikhovsky D , Chernov I
Published: July 2020

During the summer field season of 2019, the state of stands in the border zone of Russia and Finland was assessed on the basis of previously established regular network of permanent sample plots (PSP) of the ICP-Forests program. The research was conducted on the territory of the Vyborg district of the Leningrad region located closely to Finnish border. PSP are arranged as a regular network with a step of 4-8 km. Each PSP is a 4-element cluster, strongly oriented to North-South and West-East, consisting of 4 subplots, on each of which evaluated the health state of 6 specially selected model trees. Also occurrence of natural damaging factors such as insects, deceases, wind withdrawals, snow and frost damage as well as manmade such as forest fires, air pollution, garbage dump was registered. Special attention was paid to assessing the availability and stock of dead wood. All collected data was put into special database and analyzed using MapInfo 10.0 Professional software to reveal spatial regularities in tree stands health status characteristics. The concept of tree stand “temperature” was used in statistical analysis of trees distribution over damage classes to interpret the tree stands health status in more holistic and transparent way.
Solution of urgent problems of training specialists for the forest industry within the framework of the international project «Digital Forest Pedagogy»
Authors: Gromskaya L , Zhuk Yu , Kuznezov E , Katsadze V
Published: July 2020

In the article the problems of high forest education are considered. The problems associated with organization of an effective training process for the forest sector specialists have been highlighted. The urgency of raising the qualification and competence of specialists of the forest industry by using innovative teaching methods in training is justified. Possibilities of use of distance educational technologies for training of students and for improvement of professional skills of workers of the enterprises of forest sector are considered. Possibilities of the development of distance learning technologies which are realized by the international project of cross-border cooperation of South-East Finland and Russia KS1027 “Digital forester pedagogy”(DIGIFOR) are presented.
Opportunities and prospects of IoT application in landscape architecture, design and information and communication technology
Authors: Kalambet M , Yagotinceva N , Kolbina O. , Yagotinceva T. , Aksenova A.
Published: July 2020

Article represents the application of mathematical device for the calculation of irrigation regimes in drip irrigation systems. The accounting of both soil-climatic and physiological parameters of plants has been introduced. An example of calculating the norm of irrigation in the operational planning of drip irrigation modes is given. An option has been developed for introducing intelligent systems for operational planning of irrigation.
Digital simulation of forest multioperation machine operation
Authors: Karpachev S , Bykovskiy M
Published: July 2020

In this article, an innovating multi-operational forest machine (MOFM) is proposed. MOFM is based on the tractor processor (TP) and it is planned for bucking trees and making bundles from waste wood. The article presents the results of digital simulation experiments with MOFM compared with TP. The article gives the results of modelling of forests with a reserve of 150 m3/ha and with an average volume of tree trunk volume 0.40 M
3. In the article, the length of the winch rope is assumed from 10 to 30 m. Experiments were performed for different technology options. When working in parallel operations of the MOFM and winch, productivity increases with increasing skidding distance. Productivity increases until the skidding cycle time is less than the MOFM cycle time. After that, MOFM productivity decreases. For our case, the optimal skidding distance is close to 25 m. The length of the queue of trees to MOFM is increased as the skidding distance increases. The queue length stops growing when the skidding distance is 25-30 m. Digital simulation models were realized as computer programs. These models allow you to choose rational MOFM parameters for different forest characteristics.