bluuebunny/crossref_metadata_2025 huggingface dataset:
OPTICAL PROPERTIES AND LINEAR ELECTRO-OPTIC EFFECT IN FERROELECTRIC SINGLE CRYSTAL (KxNa1-x)0.4(SryBa1-y)0.8Nb2O6
Authors: XU YU-HUAN  , CHEN HUAN-CHU  ,   (1)山东大学晶体材料研究所; (2)中山大学物理系
Published: November 2020

This paper describes the measurements of optical properties and linear electro-optic effect in ferroelectric single crystal (KxNa1-x)0.4(SryBa1-y)0.8 Nb2O6. This crystal exhibits a large birefringence, and has a transparency range from 4000 ? to 5.6μm. The low halfwave voltage of (KxNa1-x)0.4 (Sry,Ba1-y)0.8 Nb2O6 gives a high value n03·rc of 730×10-12m/V, which is the figure of merit for EO modulator materials. The threshold energy of 600MW/cm2 (4pps) for laser damage makes (KxNa1-x)0.4 (SryBa1-y)0.8Nb2O6 attractive for large power laser modulation.
SUPPRESSING THE TEARING MODES IN TOKAMAK BY ELECTRON CYCLOTRON RESONANCE HEATING
Authors: Wang Mao-quan  , Zhan Ru-juan  ,   中国科学院等离子体物理研究所
Published: November 2020

Using the localization of electron cyclotron resonance heating, the profile of plasma current is improved so that the conditions of stabilities of tearing modes are also improved. As long as the absorbed region of electron cyclotron resonance heating covers the resonance layer of tearing modes, the effect of stabilizinl is very good. It is not necessary to require that electron cyclotron resonance surface must coincide with that of tearing mode strictly. In the period of electron cyclotron heating, the tearing mode is suppressed effectively.
REALIZING OPTICAL GENERAL TRANSFORM BY DUAL HOLOGRAPHIC LENSES
Authors: DONG BI-ZHEN  , GU BEN-YUAN  ,   中国科学院物理研究所
Published: November 2020

For the general case (either paraxial approximation or non-paraxial situation) and the case of discrete sample, we show that any given linear transform can be achieved by dual phase-amplitude mask optical system. Using feed-back iteration approach, the specific formulae to design the phase-amplitude distributions of dual masks are obtained. Adopting four dimension al Walsh transfom in three orders as examples, we have given the phase-amplitude distributions for masks and evaluated the approiach degree. These results axe relatively satisfactory. It shows the present proposal is reasonable and useful.
THE RESISTIVE STATE OF NON-EQUILIBRIUM SUPERCONDUCTOR NEAR Tc
Authors: YANG QIAN-SHENG  , YIN BO  , LIU GUI-RONG  , WANG XIAO-LIN  ,   中国科学院物理研究所
Published: November 2020

Superconducting Sn films are driven into the non-equililbrium state by tunnel injection of quasi-particles. The voltage across the films starts to appear when injection current increase to a certain value. Near the transition temperature of the Sn films, Tc, the corresponding resistance increase rapidly with increasing temprature. The behavior is similar to the resistance of the normal-superconductor interface. But, the observed effect is orders of magnitude larger than N-S interface resistance and the value of resistance will decrease suddenly, even vanish, when the injection current increases to a higher threshold value I".
TWO-PHOTON RESONANCE FLUORESCENCE DISTRIBUTION
Authors: PENG JIN-SHENG  ,   华中师范大学物理系
Published: November 2020

The two-photon resonance fluoresence distribution of a two-level atom is investigated. The spectrum and intensity distribution off two-photon resonance fluoresence is obtained by a canonical transformation of the Hamiltonian of the system and from the solution of the Heisenberg equations of fluoresence field operators.
COHERENT-POTENTIAL APPROXIMATION FOR AMORPHOUS FERROMAGNETIC Fe-TM-B ALLOYS
Authors: CHEN JIN-CHANG  , SHI SHUANG-HE  , ZHAO JIAN-GAO  , ZHAN WEN-SHAN  , SHEN BAO-GEN  ,   (1)北京航空学院应用数理系; (2)北京师范学院物理系; (3)中国科学院物理研究所
Published: November 2020

A concentration-dependent Curie temperature for amorphous (Fe1-xTMx)1-yBy alloys is given as a solution of a cubic equation using the coherent-potential approximation; and a conclusion has been reached for the exchange inreraction, that JFe-Fe is positive, JTM-TM and JFe-TM are negative. The present conclusion is different from Onodera's result for Fe-Mn-B alloys.
THEORETIC ANALYSIS OF I-V CHARACTERISTICS IN JOSEPHSON JUNCTION
Authors: QIAN MIN  , PAN TAO  , LIU ZHENG-RONG  ,   (1)安徽大学; (2)北京大学
Published: November 2020

In this paper, we analyse the chaos, steps and hysterisis in the I-V characteristics of Joseph-son junction theoretically, and obtain corresponding analytic expressions. These results are in agreement with experimental results.
THE INTERACTION OF PARTICLES WITH CAVITONS IN PLASMA
Authors: HE XIAN-TU  ,   应用物理与计算数学研究所
Published: November 2020

Starting from Vlasov-Doisson equations, the coupled dynamics equations for slowly varying electron distribution function δFe, slowly varying field Es and fast varying field E are derived and the system of above equations is analytically solved. Thus, the interactions of the particles distribution functions with solitons are revealed. Furthermore, the collapse motions of δFe Es. E for higher dimensions and their many cavitons behavior are discussed.
THE EXACT PATH INTEGRAL SOLUTION OF MORSE OSCILLATOR
Authors: MA YONG-JIAN  , XU BO-WEI  ,   (1)兰州大学现代物理系; (2)上海交通大学物理系
Published: November 2020

By using the point canonical transformation in path integral method, we obtained the exact wave functions of one dimensional Morse oscillator.
EXCITON-PHONON INTERACTION IN ALKALI HALIDE CRYSTALS
Authors: ZHENG HANG  , FANG JUN-XIN  ,   上海交通大学应用物理系
Published: November 2020

This article deals with the exciton-phonon interaction which has important effects on the properties of the charge transfer excitons (CTE) in alkali halide crystals. An interaction mechanism: the modulation of the Hamiltonian of the CTE system by the vibrations of the constituent ions, which may play an important role, is studied. The CTE-phonon interaction Hamiltonian is derived. From this interaction Hamiltonian, we have discussed the lifetime of the CTE. The linewidths calculated self-consistently under proper approximations agree semiquantitatively with the data measured by experiments in the literature. So we consider that this interaction Hamiltonian may present the important exciton-phonon interaction in alkali halide crystals.
THE EQUATION OF MOTION OF MAGNETIC DOMAIN WALLS IN A COMPOSED EXTERNAL FIELD AND ITS APPLICATION TO THE MAGNETOELA-STIC INTERNAL FRICTION
Authors: ZHEN WEN-GUANG  , ZHANG JIN-XIU  ,   中山大学物理系
Published: November 2020

It has been found that the forces on the domain walls (DWs) in ferromagnetic material for measuring internal friction (IF) when the magnetic field (H) is increased at constant rate (a) are: (1) main driving force caused by the H, namely A00+A10at; (2) harmonic perturbation force A30sinωt; (3) interaction force which is proportional to A10at, A30sinωt and a resistant force depending on the internal stress field and anisotropy field A20sinωt. The equation of motion of DWs can be written as ρ(d2 x)/(dt2) + r(dx)/(dt)+κx = A00 + A10at + A20t sinωt + A30 sin ωt where A00,A10,A20,A30 are constants depending on material chosen and test condition; ρ is the mass density, γ is the viscous damping parameter and κ is the coefficient of restoring force. The IF caused by DWs motion can be obtained from the solution of the equation of motion as follows Qm-1=B1 (Eλsδ)/(Ms2Hm) (dM)/(dH)·α/ω (If for α≠0) Q0-1=B2 (γωE)/(κ2) (If for α=0) where E is the modulus, λs is the saturation magnetostriction,Ms is the saturation magnetization, Hm is a critical field at whichthe reversible motion of DWs becomes irreversible B1, B2 are dimensionless positive numbers. When α≠0, the visco-elastic IF may be initiated and the IF varies with α/ω; when α= 0, the low-frequency micro-eddy current IF may be initiated and the IF varies with ω. The calculated results are compared with experimental data and interface dynamics.
THE THEORY OF SUPERCONDUCTIVITY IN KONDO LATTICE
Authors: XU JI-HAI  , SU ZHAO-BING  , LI TIE-CHENG  ,   (1)中国科学院理论物理研究所; (2)中国科学院物理研究所; (3)中国科学院物理研究所,山东大学物理系
Published: November 2020

S-wave and P-wave superconductivity in Kondo lattice is theoretically studied in connection with heavy-fermion superconductivity (HFS). The hybridization between f-electron and conduction electron is investigated consistently and the corresponding quantities have been calculated in detail in the generalized Nambu formalism. It is shown that if one thinks f-electrons are responsible for superconductivity, for S-wave paired state, the superconducting transition temperature is in agreement with that of Tachiki et al., but the specific heat jump is not, our result is more appropriate than theirs. For P-wave paired state, the HFSs described by a Kondo lattice model are essentially almost localized Fermi superfluids, with a small modification. The effects of impurities on S- and P-wave paired states have been studied in detail respectively, and the conditions of the appearence of gapless superconductivity have been obtained for each case .
THE THEORY OF HOMOTOPY GROUP WITH MULTIPLE BASE POINTS
Authors: LI BO-ZANG  , YAN FENG-LI  ,   (1)河北师范大学物理系; (2)中国科学院物理研究所
Published: November 2020

A theorem is established that if the topoiogical space V is simply connected, the set of homotopy classes for the Sn→V continuous maps with N(≥1) base points, πn (V; v1, v2,…, vN), can be constructed into group isomorphic to the homotopy group of order n with single base point, πn(V) (referred to as the homotopy group of order n with N base points). Here, the condition that V is simply connected could not in general be neglected. Some corollaries are given. The application of this theorem and its corollaries to the topoiogical classification of magnetization states in ferromagnet is briefly- described with a few examples.
THE CRITICAL TEMPERATURE CURVE OF THE GENERALIZED MIXED SPIN MODEL
Authors: TANG KUN-FA  , HU JIA-ZHEN  ,   上海交通大学应用物理系,凝聚态物理研究所
Published: November 2020

The equiscale transformation in the same universality class developed previously[a,5] is applied to the generalized mixed spin model, the curve of the crkical temperature is obtained for this model.
INVESTIGATION OF SOLID-SOLID SURFACE ADSORPTION OF Eu2O3 ON η-Al2O AND SiO2 GEL
Authors: LIU RONG-CHUAN  , XIA YUAN-FU  , H. ENGELMANN  , J. F. JING  , U. GONSER  , N. KRAMER  , JIANG HUA-LI  ,   (1)德意志联邦共和国萨尔大学应用物理系; (2)南京大学物理系; (3)苏州大学物理系
Published: November 2020

Solid-solid surface adsorption of Eu2O3 on η-Al2O3 and SiO2 gel has been investigated using M?ssbauer spectroscopy and X-ray diffraction analysis. The results suggest that after appropriate treatment Eu2O3 disperses spontaneously onto the surface of both supporter materials. No indications of remaining crystalline Eu2O3 have been found below the limiting mono-layer concentration. In the case of η-Al2O3, it is suggested that below the limiting monolayer capacity Eu2O3 covers the surface in a disordered monolayer configuration. For higher Eu2O3 contents a second layer starts to appear with a structure similar to that of the bulk crystalline phase. In the case of SiO2 gel, it is suggested that the monolayer as well as the second layer configuration of Eu2O3 is highly disordered. It seems that the M?ssbauer parameters, isomer shift and linewidth allow additional insight into the surface layer structures formed by solid-solid adsorption.
EXTRAORDINARY BRAGG DIFFRACTION OF SURFACE ACOUSTIC WAVE ON ACOUSTIC GRATING
Authors: WANG ZUO-QING  , WANG CHENG-HAO  , ZHOU SU-HUA  ,   中国科学院声学研究所
Published: November 2020

In this paper, the Bragg diffraction of SAW on acoustic grating is investigated by incorporating the anisotropy of the substrates. In the analysis, the difference between the incident wave, the fundamental wave and spatial harmonic wave in grating region and the diffraction waves in transmission region is phenomenologically described by using their different corresponding velocities. The experimental results for the diffraction of SAW on acoustic grating which is fabricated on Y-cut LiNbO3 are presented. The comparison of the experimental results with the analyzed results obtained on isotropy approximation shows that the discrepancy is significant. The "extraordinary Bragg diffraction" equations are obtained by using the coupled-waves method which takes the anisotropy of the substrates into consideration. It is shown that the calculated results based on "extraordinary Bragg diffraction" equations are coincident with the experimental results fairly well.
POLARITIONS IN FINITE SUPERLATTICES
Authors: SHI HANG  , CAI JIAN-HUA  ,   (1)南京大学固体物理研究所; (2)上海交通大学凝聚态物理研究所
Published: November 2020

We generalize our former work to superlattices with finite number of layers, and obtain the corresponding dispersion relations for the bulk as well as the surface modes. Numerical computations show a superlattice with 20 supercells behaves already very near to an infinite su-perlattice with regard to the propagation characteristics of electromagnetic waves. However, important differences appear when the number of supercells is small.
MEASUREMENT OF THE DENSITY OF GAP STATES IN AMORPHOUS SEMICONDUCTORS BY INFRARED STIMULATED CURRENTS
Authors: WU WEN-HAO  , HAN DA-XING  ,   (1)中国科学院物理研究所; (2)中国科学院物理研究所,中国科学院上海技术物理研究所
Published: November 2020

A new method of measuring the density of gap states in amorphous semiconductors by employing a two-beam photoconductivity experiment is reported. In the two-beam experiment, an intensive bandgap pump light is used to create non-equilibrium carriers and most of these carriers are trapped in the gap states. Then, at a latter time td after turning off the pump light, these trapped carriers are re-excited by an infrared probe light A photoconductivity overshoot, which depends on the delay time and temperature, is observed in the onset process of IR excited photoconductivity. The results are discussed using the multiple trapping theory. The distribution of the density of gap states is deduced from the experiment.
Effects of Seed Rate and Row Spacing on Yield and Yield Components of Teff (Eragrostis tef [Zucc.] Trotter.) in Kiltu Kara Distirct of Western Ethiopia
Authors: Kitata Shifera , Abera Tolera , Nandeshwar Bhupesh
Published: November 2020

Teff is a major staple cereal crop in Ethiopia. However, its productivity is limited due to lack of appropriate sowing methods and utilization of improper seed rate are among the major once. Hence, a field experiment was conducted in Kiltu Kara District to determine the effects of seed rate and row spacing on yield and yield components of teff. Four levels of seed rates (10, 15, 20 and 25 kg ha-1) and three rows spacing (15, 20 and 25cm) used and combined 12 treatments in total. The experiment was laid out as a randomized complete block design with a factorial arrangement in three replications. All yield components teff were significantly affected by different row spacing except straw yields of teff. The interaction of seed rate and row spacing showed significant difference for yield and yield components of teff. Significantly higher mean values of teff were found by the interaction of 10 kg seed rate ha-1 and 25 cm row spacing. Significantly higher panicle length (36.9), number of tillers per plant (5), number of productive tillers per plant (4) of teff was recorded from interaction of 10 kg seed rate ha-1 and 25 cm row spacing. Higher dry biomass (2591 kg ha-1) and grain yields (1267 kg ha-1) of teff were recorded from interaction of 10 kg seed rate ha-1 and 25 cm row spacing. Mean of highest harvest index (49%) of teff was recorded from interaction of 10 kg seed rate ha-1 and 25cm row spacing as compared to others. Significantly higher straw yields (1488 kg ha-1) was recorded from interaction of 15kg seed rate ha-1 and 20 cm row spacing as compared to other treatment combinations. Therefore, the use of 10 kg seed rate ha-1 together with 25 cm row spacing was the optimum seed rate and row spacing and 10 kg ha-1 was profitable for the production of teff. To make definite conclusion further research for more seasons and location is required to give recommendation for the study area.
Agro-Morphological Characterization of Three Cultivated Legumes: Two Varieties of Soybean (Glycine max L.) and One Variety of Mungbean (Vigna radiata L.)
Authors: Yao Koffi Bertin , Kouakou Kouassi Joseph , Yoboue Aya Viviane , Kouakou Tanoh Hilaire
Published: November 2020

To contribute to the restoration of tropical soils fertility, the agro-morphological and yield characteristics of three cultivated legumes [two beige seeded varieties of soybean (Glycine max L.): one from  Côte d’Ivoire (BVCI) and the other, from Benin (BVB) and a green  seeded mungbean variety (Vigna radiata L)  from Côte d'Ivoire (MVCI)] were studied.  The legumes seeds were sown and the resulting plants were monitored until harvest. The data relating to the plants phenological, morphological and yield parameters were statistically processed through one-way analysis of variance (ANOVA 1).  The results of phenological observations indicated that the mungbean (MVCI) was earlier than both soybean varieties (BVCI followed by BVB). Morphologically, plants of the late soybean varieties (BVCI and BVB) were higher, more branched with a large wingspan, and produced more panicles than the early variety of mungbean (MVCI). In addition, mungbean variety (MVCI) produced long tapered pods containing small seeds while the soybean varieties produced shorter but wider pods containing large seeds.  In terms of yied, both late soybean varieties (BVCI and BVB) produced large dry biomass, more pods with higher seed yield, dry weight and 100 seed weight than the early variety of mungbean (MVCI).

Significance: The precocious nature of mungbean makes it an important plant for the fight against climate change, especially against drought. Due to their good branching and significant plant spread, both late varieties of soybean (BVCI and BVB) have high potential of being selected for soil protection and weed control, as well as for food production because of their high pod yield, seed and dry biomass.
Development and Validation of Simple, Rapid and Sensitive High- Performance Liquid Chromatographic Method for the Determination of Butenafine Hydrochloride
Authors: Ansari Mohammad Javed , Ahmed Mohammed Muqtader , Anwer Md. Khalid , Aldawsari Mohammed F. , Shahrani Saad M. Al , Ahmad Niyaz
Published: November 2020

Aims: The current paper reports a simple, rapid, sensitive, accurate, and precise Reverse-phase high performance liquid chromatography (RP-HPLC) method with wide range of estimation to determine butenafine hydrochloride in nanosponges. This method has been validated as per ICH norms.

Study Design:  Experimental design with influence of variables such as mobile phase composition, flow rate, temperature and wavelength on the chromatographic peaks.

Place and Duration of Study: Department of Pharmaceutics, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj, Saudi Arabia between Jan 2020 and March 2020.

Methodology: Separation was achieved by utilizing the most commonly used reverse phase column (C-18, 5 μm, 150 mm x 4.6 mm) set at 30ºC and quantified by UV detection at 280 nm after isocratic elution from a mobile phase (70:30 v/v of methanol: phosphate buffer pH 3.0) flowing at 1 ml/min.

Results: A sharp and symmetrical peak was observed at 4.08 ± 0.01 minutes. The low variation in peak area and retention time (1.12% and 0.29%, respectively) and a high number of theoretical plates (>2000) indicated this method’s efficiency and suitability. The least square linear regression analysis (Y = 9265.5 X + 1961.4) showed excellent correlation (r2 = 0.999 ± 0.0003) between concentration and peak area of butenafine hydrochloride through a wide concentration range of 1–50 µg/ml. The limits of detection and quantification (LOD and LOQ) were 0.18 µg/ml and 0.57 µg/ml, respectively. The assay or determinations were accurate, precise and reproducible with mean accuracy and mean relative standard deviation of precision of 101.53 ± 0.43% and 0.51 ± 0.11% respectively.

Conclusion: The developed RP-HPLC method was simple, sensitive, reproducible with wide range of estimation of butenafine hydrochloride in the nanosponges. The proposed method could be used for the analysis of butenafine hydrochloride in the conventional pharmaceutical formulations such as tablets, syrup, creams including novel formulations such as nanoparticles, nanosponges, nanoemulsions. The proposed method overcomes the specificity, sensitivity and reproducibility related issues of ultraviolet-visible spectroscopy.
Lifshitz Transition and Non‐Fermi Liquid Behavior in Highly Doped Semimetals
Authors: Kang Kyungrok , Kim Won June , Kim Dohyun , Kim Sera , Ji Byungdo , Keum Dong Hoon , Cho Suyeon , Kim Young‐Min , Lebègue Sébastien , Yang Heejun
Published: November 2020

The classical Fermi liquid theory and Drude model have provided fundamental ways to understand the resistivity of most metals. The violation of the classical theory, known as non‐Fermi liquid (NFL) transport, appears in certain metals, including topological semimetals, but quantitative understanding of the NFL behavior has not yet been established. In particular, the determination of the non‐quadratic temperature exponent in the resistivity, a sign of NFL behavior, remains a puzzling issue. Here, a physical model to quantitatively explain the Lifshitz transition and NFL behavior in highly doped (a carrier density of ≈1022 cm−3) monoclinic Nb2Se3 is reported. Hall and magnetoresistance measurements, the two‐band Drude model, and first‐principles calculations demonstrate an apparent chemical potential shift by temperature in monoclinic Nb2Se3, which induces a Lifshitz transition and NFL behavior in the material. Accordingly, the non‐quadratic temperature exponent in the resistivity can be quantitatively determined by the chemical potential shift under the framework of Fermi liquid theory. This model provides a new experimental insight for nontrivial transport with NFL behavior or sign inversion of Seebeck coefficients in emerging materials.
Achromatic Dielectric Metasurface with Linear Phase Gradient in the Terahertz Domain
Authors: Jia Ridong , Gao Yufei , Xu Quan , Feng Xi , Wang Qingwei , Gu Jianqiang , Tian Zhen , Ouyang Chunmei , Han Jiaguang , Zhang Weili
Published: November 2020

The notion of metasurface has inspired the innovation of various functional devices in the terahertz band, but the intrisinc dispersion restricts their application in broadband scenarios. Here, two terahertz achromatic linear‐phase‐gradient metasurface devices are demonstrated, which are a beam deflector and a beam splitter, respectively. The phase and dispersion of the metasurfaces are simultaneously engineered by changing the geometric parameters of the unit cells made of silicon gratings and pillars. The simulated and experimental results demonstrate the achromatic feasibility of the beam deflector from 0.6 to 1.2 THz and of the beam splitter from 0.6 to 1.1 THz. The transmittances and the splitting ratios of the achromatic beam splitter are also analyzed. The metasurface based achromatic beam deflector and splitter presented here not only enrich the terahertz functional devices, but the methods and structures may also promote the research of broadband terahertz metasurfaces.
Metal‐Free, Multicomponent Anti‐Markovnikov Hydroarylsulfonylation and Alkoxyarylsulfonylation of Vinyl Arenes
Authors: Das Pritha , Das Subhodeep , Varalaxmi Kasarla , Jana Ranjan
Published: November 2020

A unified strategy for the hydro‐arylsulfonylation of vinyl arenes has been developed under catalyst, additive‐free conditions at room temperature from the corresponding aryldiazonium salts, DABSO (DABCO ⋅ 2SO2), and thiophenol as hydrogen atom transfer (HAT) reagent. Mechanistically, an incipient arylsulfonyl radical is generated from the corresponding aryl diazonium salts and DABSO which undergoes anti‐Markovnikov addition to styrenes followed by hydrogen atom transfer from thiophenol. Interestingly, this multi‐component reaction is highly chemoselective suppressing deleterious thiosulfonylation and thiol‐ene reactions. Tuning the reaction conditions, a four‐component difunctionalization with alkoxy group has been achieved using 1,4‐dicyanobenzene as an oxidant. Furthermore, base‐promoted elimination to form vinyl sulfone has been also examined. The practicability of this present reaction has been demonstrated by the ex situ generation of sulfur dioxide in an H‐type reaction vessel and subsequent hydro‐ and alkoxyarylsulfonylation in good to moderate yields. The hydroarylsulfonylation reaction is scalable and applied to a metal‐free synthesis of the key intermediate for an anti‐migraine drug Eletriptan.

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Agricultural Trade Costs
Authors: Beghin John C. , Schweizer Heidi
Published: November 2020

We examine the recent evolution of salient trade costs in agricultural and food markets, and changes in their composition. We review ways to measure costs and provide guidance with policy prescriptions to reduce them. We pay attention to transportation costs, border measures, and standard‐like nontariff measures. By pointing out limitations in current approaches and recent developments, we aim to improve our understanding of their effects and derive clearer prescriptions. We suggest promising directions for further research and investigation of agricultural trade costs, including on the emerging debate on gene editing and trade, transportation costs, and mainstreaming recent advances in analyzing nontariff measures.
Unprecedented Crisis Calls for Unprecedented Policy Responses
Authors: Johansson Robert , Hungerford Ashley , Sewadeh Mirvat , Effland Anne
Published: November 2020

The COVID‐19 pandemic presented a severe crisis to the agricultural sector and the economy at large. To confront it, the administration and Congress had to mobilize vast resources very quickly and introduce creative emergency measures to mitigate the unprecedented impacts on the economy. This article takes a closer look at the impacts of the COVID‐19 pandemic on the agricultural sector and the policy measures that USDA implemented to help farmers and ranchers weather the immediate crisis.
Silflower seed and biomass responses to plant density and nitrogen fertilization
Authors: Schiffner Sydney , Jungers Jacob M. , Hulke Brent S. , Van Tassel David L. , Smith Kevin P. , Sheaffer Craig C.
Published: November 2020

Silflower (Silphium integrifolium Michx.) is a potential perennial oilseed crop that can provide ecosystem services; however, its seed, oil, and biomass yield potential are unknown. Our objectives were to determine the effects of planting density and N fertilizer on silflower seed, oil, and biomass yields and seed yield components for 3 yr after establishment. Experiments tested six planting densities on two soil types, and five N rates and two planting densities on one soil type. Averaged over years and soil types, increasing planting density from 11,954 to 53,792 plants ha−1 increased biomass yield (BY), but decreased seed heads plant−1 and seeds plant−1. Planting density had no effect on seed yield (SY) or oil yield (OY), other seed related variables, or harvest index. On a sandy soil, SY and OY increased linearly with N rates from 0 to 180 kg ha−1 in the year after seeding but were not affected by N fertilization rates in subsequent years. At 180 kg N ha−1, SY, OY, and BY were 1,651 kg ha−1, 381 kg ha−1, and 10.5 Mg ha−1, respectively, in the year following seeding but declined thereafter. Over both experiments SY and OY were positively correlated (r = .99) and together associated with seed heads plant−1, seeds head−1, and seeds plant−1. Relative to annual oilseed crops, seed and oil yields for this new perennial species are low. Germplasm improvement for seed and oil yield and agronomic research to maintain yields as stands age are critical to develop this new perennial oilseed crop.
In/Cu Catalyzed Multiple C−N/C−C Bond Formation via Multiple Bond Cleavage in a Three Component Synthesis of Arylimidazopyridine Carboxylates
Authors: Roslan Irwan Iskandar , Ng Kian‐Hong , Alhooshani Khalid R. , Jaenicke Stephan , Chuah Gaik‐Khuan
Published: November 2020

A protocol for InIII and CuI co‐catalyzed synthesis of a wide array of arylimidazopyridine carboxylates by three components coupling of benzaldehydes, malonic esters and 2‐aminopyridines is described. The reaction proceeds through a reaction cascade of Knoevenagel condensation, 1,4‐conjugate addition, aerobic dehydrogenation, Ortoleva‐King reaction and decarboxylation. Multiple C−N and C−C bond formations in addition to multiple C−C, C−H, C−O, and N−H bond cleavages are involved in forming the product.
Combining Incompatible Processes for Deracemization of a Praziquantel Derivative under Flow Conditions
Authors: Valenti Giulio , Tinnemans Paul , Baglai Iaroslav , Noorduin Willem L. , Kaptein Bernard , Leeman Michel , ter Horst Joop H. , Kellogg Richard M.
Published: November 2020

An efficient deracemization method for conversion of the racemate to the desirable (R)‐enantiomer of Praziquantel has been developed by coupling incompatible racemization and crystallization processes. By a library approach, a derivative that crystallizes as a conglomerate has been identified. Racemization occurs via reversible hydrogenation over a palladium on carbon (Pd/C) packed column at 130 °C, whereas deracemization is achieved by alternating crystal growth/dissolution steps with temperature cycling between 5–15 °C. These incompatible processes are combined by means of a flow system resulting in complete deracemization of the solid phase to the desired (R)‐enantiomer (98 % ee). Such an unprecedented deracemization by a decoupled crystallization/racemization approach can readily be turned into a practical process and opens new opportunities for the development of essential enantiomerically pure building blocks that require harsh methods for racemization.
Translation of Mycobacterium Survival Strategy to Develop a Lipo‐peptide based Fusion Inhibitor**
Authors: Sardar Avijit , Lahiri Aritraa , Kamble Mithila , Mallick Amirul I. , Tarafdar Pradip K.
Published: November 2020

The entry of enveloped virus requires the fusion of viral and host cell membranes. An effective fusion inhibitor aiming at impeding such membrane fusion may emerge as a broad‐spectrum antiviral agent against a wide range of viral infections. Mycobacterium survives inside the phagosome by inhibiting phagosome–lysosome fusion with the help of a coat protein coronin 1. Structural analysis of coronin 1 and other WD40‐repeat protein suggest that the trp‐asp (WD) sequence is placed at distorted β‐meander motif (more exposed) in coronin 1. The unique structural feature of coronin 1 was explored to identify a simple lipo‐peptide sequence (myr‐WD), which effectively inhibits membrane fusion by modulating the interfacial order, water penetration, and surface potential. The mycobacterium inspired lipo‐dipeptide was successfully tested to combat type 1 influenza virus (H1N1) and murine coronavirus infections as a potential broad‐spectrum antiviral agent.
Mixed Noble‐Gas Compounds of Krypton(II) and Xenon(VI); [F5Xe(FKrF)AsF6] and [F5Xe(FKrF)2AsF6]
Authors: Lozinšek Matic , Mercier Hélène P. A. , Schrobilgen Gary J.
Published: November 2020

The coordination chemistry of KrF2 has been limited in contrast with that of XeF2, which exhibits a far richer coordination chemistry with main‐group and transition‐metal cations. In the present work, reactions of [XeF5][AsF6] with KrF2 in anhydrous HF solvent afforded [F5Xe(FKrF)AsF6] and [F5Xe(FKrF)2AsF6], the first mixed krypton/xenon compounds. X‐ray crystal structures and Raman spectra show the KrF2 ligands and [AsF6]− anions are F‐coordinated to the xenon atoms of the [XeF5]+ cations. Quantum‐chemical calculations are consistent with essentially noncovalent ligand−xenon bonds that may be described in terms of σ‐hole bonding. These complexes significantly extend the XeF2–KrF2 analogy and the limited chemistry of krypton by introducing a new class of coordination compound in which KrF2 functions as a ligand that coordinates to xenon(VI). The HF solvates, [F5Xe(FH)AsF6] and [F5Xe(FH)SbF6], are also characterized in this study and they provide rare examples of HF coordinated to xenon(VI).
Fast Enantio‐ and Chemoselective Arylation of Ketones with Organoboronic Esters Enabled by Nickel/N‐Heterocyclic Carbene Catalysis
Authors: Cai Yuan , Ruan Lin‐Xin , Rahman Abdul , Shi Shi‐Liang
Published: November 2020

A general, efficient, highly enantio‐ and chemoselective N‐heterocyclic carbene (NHC)/Ni‐catalyzed addition of readily available and stable arylboronic esters to ketones is reported. This protocol provides unexpectedly fast access (usually 10 min) to various chiral tertiary alcohols with exceptionally broad substrate scope and excellent functional group tolerance (76 examples, up to 98 % ee). This process is orthogonal to other known Ni‐mediated Suzuki–Miyaura couplings, as it tolerates aryl chlorides, fluorides, ethers, esters, amides, nitriles, and alkyl chlorides. The reaction is applied to late‐stage modifications of various densely functionalized medicinally relevant molecules. Preliminary mechanistic studies suggest that a rare enantioselective η2‐coordinating activation of ketone carbonyls is involved. This cross‐coupling‐like mechanism is expected to enable other challenging transformations of ketones.
The Impact of Bilingualism on the Executive Functions of Autistic Children: A Study of English–Arabic Children
Authors: Sharaan Shereen , Fletcher‐Watson Sue , MacPherson Sarah E.
Published: November 2020

There is evidence to suggest that certain executive functions are impaired in autistic children, contributing to many daily challenges. Regular use of two languages has the potential to positively influence executive functions, though evidence is mixed. Little is known about the impact of bilingualism on the executive functions of autistic children, with only a handful of studies published worldwide to date. This study investigated the impact of bilingualism on sustained attention, interference control, flexible switching and working memory, in Arabic–English autistic children (n = 27) and their typically developing peers (n = 66), aged 5–12 years old. Groups were matched on age, nonverbal IQ and socioeconomic status, and completed a battery of computerized tests. Results showed an advantage for bilingual autistic children relative to their monolingual peers in sustained attention, and equivalent performance between bilingual and monolingual autistic children on all other executive functions. There were no generalized positive effects of bilingualism, and typically‐developing children performed better than autistic children on all measures. The findings indicate that bilingualism does not negatively impact the executive function skills of autistic children, and that it might mitigate difficulties in sustained attention.

Lay Summary

Contrary to widespread belief, but in line with previous research, this study showed that speaking two languages did not harm thinking skills in autistic children. The thinking skills evaluated in this study included the ability to focus over a period of time, the ability to resist distractions, the ability to move back and forth between tasks, and the ability to use short‐term memory. In fact, speaking two languages might help reduce difficulties that autistic children might face when focusing over a period of time.
Improving viral filtration capacity in biomanufacturing processes using aggregate binding properties of polyamide‐6,6
Authors: Stanevich Vitali , Pachalla Abhishek , Nunez Briana , McInnes Mark , Nieder Christopher , Schreffler John
Published: November 2020

Virus retention filtration is a common step in modern biopharmaceutical manufacturing as it enables efficient removal of potential adventitious and endogenous viruses via size exclusion. Modern parvovirus retention filters have significantly improved fluxes and parvovirus retention in comparison to earlier versions of these filters. However, these filters may be more susceptible to premature fouling and require more effort for process optimization. Here, we demonstrate that polyamide‐6,6 (nylon‐6,6) membranes when used as prefilters can increase the capacity of these Parvovirus retentive filters that are less susceptible to premature fouling. We found that the mechanism of polyamide‐mediated filtration improvement can be explained by the binding of monoclonal antibody (mAb) aggregates with a diameter of 20–100 nm, and we show that this mechanism is shared by other types of adsorptive prefilters. Finally, by the combination of mobile phase screening, additive spiking, and molecular dynamics simulations, we show that polyamide‐6,6 removes mAb aggregates through hydrophobic interactions making its design space potentially complementary to other available prefilters. Our studies support the aggregate‐mediated mechanism of flux decay during viral filtration and suggest that polyamide‐6,6 could be considered as an alternative cost‐effective option to extend the capacity of viral filters.
Lassa hemorrhagic shock syndrome‐on‐a‐chip
Authors: Tang Huaqi , Abouleila Yasmine , Mashaghi Alireza
Published: November 2020

Lack of experimental human models hinders research on Lassa hemorrhagic fever and the development of treatment strategies. Here, we report the first chip‐based model for Lassa hemorrhagic syndrome. The chip features a microvessel interfacing collagen network as a simple mimic for extracellular matrix, allowing for quantitative and real‐time vascular integrity assessment. Luminal infusion of Lassa virus‐like particles led to a dramatic increase in vascular permeability in a viral load‐dependent manner. Using this platform, we showed that Fibrin‐derived peptide FX06 can be used to suppress the vascular integrity loss. This simple chip‐based model proved promising in the assessment of disease severity and provides an easy‐to‐use platform for future investigation of Lassa pathogenesis and drug development in a human‐like setting.
Halophilic archaea and their potential to generate renewable fuels and chemicals
Authors: Kasirajan Lakshmi , Maupin‐Furlow Julie A.
Published: November 2020

Lignocellulosic biofuels and chemicals have great potential to reduce our dependence on fossil fuels and mitigate air pollution by cutting down on greenhouse gas emissions. Chemical, thermal, and enzymatic processes are used to release the sugars from the lignocellulosic biomass for conversion to biofuels. These processes often operate at extreme pH conditions, high salt concentrations, and/or high temperature. These harsh treatments add to the cost of the biofuels, as most known biocatalysts do not operate under these conditions. To increase the economic feasibility of biofuel production, microorganisms that thrive in extreme conditions are considered as ideal resources to generate biofuels and value‐added products. Halophilic archaea (haloarchaea) are isolated from hypersaline ecosystems with high salt concentrations approaching saturation (1.5–5 M salt concentration) including environments with extremes in pH and/or temperature. The unique traits of haloarchaea and their enzymes that enable them to sustain catalytic activity in these environments make them attractive resources for use in bioconversion processes that must occur across a wide range of industrial conditions. Biocatalysts (enzymes) derived from haloarchaea occupy a unique niche in organic solvent, salt‐based, and detergent industries. This review focuses on the use of haloarchaea and their enzymes to develop and improve biofuel production. The review also highlights how haloarchaea produce value‐added products, such as antibiotics, carotenoids, and bioplastic precursors, and can do so using feedstocks considered “too salty” for most microbial processes including wastes from the olive‐mill, shell fish, and biodiesel industries.
Impact of visual typicality on the adoption of wearables
Authors: Lee Eun‐Jung
Published: November 2020

With the recent influx of IT firms and big‐name fashion brands into the wearables market, the visual design of wearables has become a crucial factor in consumer choices. However, little research exists on this topic. Drawing upon the literature of technology adoption and design aesthetics, this study examines how the visual typicality of wearables affects their adoption by consumers. More specifically, the research tests the impact of the consumer‐perceived visual typicality of smartwatches on purchase intention through the psychological antecedents to wearable adoption (i.e., effort expectancy, performance expectancy, social influence, playfulness). The hypothesized relationships among the variables were tested in an online survey with 409 U.S. participants, where fictitious smartwatch designs were employed as the stimuli. In the results, perceived visual typicality of the smartwatch designs significantly decreased perceived performance and playfulness of the watch. Perceived visual typicality also had a negative impact on participants' purchase intention. Among the four psychological antecedents to wearable adoption, perceived playfulness played the most significant role in the relationship between the visual typicality and purchase intention. The moderation effect of gender was partially supported: Visual typicality significantly decreased purchase intention for females whereas it had no impact on the wearable adoption for males.
Expanding the Toolbox of R‐Selective Amine Transaminases by Identification and Characterization of New Members
Authors: Telzerow Aline , Paris Juraj , Håkansson Maria , González‐Sabín Javier , Ríos‐Lombardía Nicolas , Gröger Harald , Morís Francisco , Schürmann Martin , Schwab Helmut , Steiner Kerstin
Published: November 2020

Amine transaminases (ATAs) are used to synthesize enantiomerically pure amines, which are building blocks for pharmaceuticals and agrochemicals. R‐selective ATAs belong to the fold type IV PLP‐dependent enzymes, and different sequence‐, structure‐ and substrate scope‐based features have been identified in the past decade. However, our knowledge is still restricted due to the limited number of characterized (R)‐ATAs, with additional bias towards fungal origin. We aimed to expand the toolbox of (R)‐ATAs and contribute to the understanding of this enzyme subfamily. We identified and characterized four new (R)‐ATAs. The ATA from Exophiala sideris contains a motif characteristic for d‐ATAs, which was previously believed to be a disqualifying factor for (R)‐ATA activity. The crystal structure of the ATA from Shinella is the first from a Gram‐negative bacterium. The ATAs from Pseudonocardia acaciae and Tetrasphaera japonica are the first characterized (R)‐ATAs with a shortened/missing N‐terminal helix. The active‐site charges vary significantly between the new and known ATAs, correlating with their diverging substrate scope.
Tetrahedral DNA Nanoconjugates for Simultaneous Measurement of Telomerase Activity and miRNA
Authors: Jiang Chenyu , Meng Fanyu , Mao Dongsheng , Tang Yuguo , Miao Peng
Published: November 2020

In this study, a tetrahedral DNA nanostructure was first self‐assembled; this was then conjugated with gold nanoparticles (AuNPs) and carbon nanodots (CDs). The fabricated nanocomposites allow simultaneous analysis of telomerase activity and miRNA with dual fluorescence channels. By further introducing an iRGD peptide sequence, the nanoconjuates can be conveniently transferred inside living cells for in situ imaging. The analytical performances and anti‐jamming capabilities are excellent. Meanwhile, the materials are highly biocompatible for intracellular applications. Therefore, the proposed biosystem shows great promise as a powerful tool for quantitative analysis of the dual biomarkers. The strategy can also be further exploited as a versatile platform for in situ detection of many other targets for early disease diagnosis.
Impact of early hospital discharge on clinical outcomes after transcatheter aortic valve implantation
Authors: Bække Pernille S. , Jørgensen Troels H. , Søndergaard Lars
Published: November 2020

Aims

Early discharge after transcatheter aortic valve implantation (TAVI) may potentially impact post‐procedural safety of the patient. The study aim was to compare safety of TAVI in patients planned for fast track hospital stay with patients planned for standard hospital stay.

Methods and results

All‐comers patients undergoing transfemoral TAVI between 2011 and 2017 were allocated to two matched groups depending whether the procedure was performed before or after transition from standard to fast track course. Data on vital status and hospitalizations were obtained through national registries.

Three hundred and nineteen matched pairs were eligible for analysis. The median length of post‐procedural stay was 3 days (IQR: 2–4) for patients in the fast track group compared to 6 days (IQR: 4–8) in the standard approach group (p < .0001). There was no difference in all‐cause mortality between groups at 30‐day (1.3% vs. 1.9%, p = .52) or 90‐day follow‐up (2.9% vs. 4.1%, p = .42). There was no difference in the risk of new permanent pacemaker implantation (PPI) in pacemaker naïve patients between groups at 30‐day (15.8% vs. 21.2%, p = .16) or 90‐day follow‐up (15.8% vs. 21.9%, p = .12). There was no difference in the rate of rehospitalization between groups between discharge and 90‐day follow‐up (2.09 per patient‐year vs. 2.09 per patient‐year, p = .99).

Conclusions

Early discharge in an all‐comers population undergoing transfemoral TAVI is safe with regards to all‐cause mortality, need for PPI, and rehospitalization.
Experimental Investigation on Single‐Droplet Deformation and Breakup in a Concave‐Wall Jet
Authors: Zhang Jing , Gao Yibo , Gong Bin , Li Yaxia , Wu Jianhua
Published: November 2020

Liquid droplets are released in the concave‐wall jet to investigate their deformation and breakup characteristics. CCl4 and water are the dispersed and continuous phases. The study reveals that the three modes of single droplets in the concave‐wall jet are non‐breakup, binary breakup, and multiple breakup. When the Weber (We) number is less than 30, the mode of binary‐breakup is primary for the droplets, however, there are only multiple‐breakup modes when We > 47. The non‐breakup and binary‐breakup modes are beneficial to the gravity and centrifugal separation because of little deformation and high axial velocity of the droplet. Effects of continuous‐phase tangential velocity and shear rate distribution on the droplet image sequence are studied. Droplet breakup occurs mainly in the region of high shear rate.
Investigation of Control Structures for a Four‐Product Laboratory Multiple Dividing‐Wall Column Using Dynamic Simulation
Authors: Preißinger Ulrich , Lukač Goran , Dejanović Igor , Grützner Thomas
Published: November 2020

The dynamic behavior of a multiple dividing‐wall column pilot plant is evaluated by means of dynamic simulation. Three different control structures are developed or adapted from the literature, which are constrained by the actual design features of the pilot plant column. Since in the present case the design of the column was chosen such that very different mixtures can be separated, it cannot be optimally designed for each of these potential mixtures. Rather, the design focused on the flexibility of the plant. All three investigated control structures were tested on feed flow rate and feed composition disturbance and allowed a robust control of the pilot plant, whereby control structure 2 is slightly better than others in terms of steady‐state deviations and less pronounced fluctuations during the dynamic phase. The transferability of control structure 2 to other variants of multiple dividing‐wall columns is easily possible.