bluuebunny/crossref_metadata_2025 huggingface dataset:
A method for natural frequency calculation of the functionally graded rectangular plate with general elastic restraints
Authors: Kim Kwanghun , Kim Kukchol , Han Cholyong , Jang Yonghuan , Han Poknam
Published: August 2020

In this study, a unified solution method to obtain the natural frequencies of the functionally graded rectangular plate (FGRP) with general elastic restraints by using ultraspherical polynomials and the Ritz method is presented. It is supposed that the material distribution properties of the FGRP depend on four different parameters. Based on the first order shear deformation plate theory, the displacement fields of the FGRP are set and boundary and continuity conditions are modeled by adopting the virtual spring technique. All displacement functions of the FGRP including boundary and continuity conditions are expressed by ultraspherical polynomials, and the natural frequencies of the FGRP are obtained by applying the Ritz method. The accuracy of the proposed method is verified by comparison with the results of the previous literature and finite element method. Finally, the effects of several parameters on the natural frequencies of the FGRP with various classical and elastic restraints are also discussed, which can be helpful to the further development of the same topic.
Effect of microfluidic processing on the viability of boar and bull spermatozoa
Authors: Hamacher Tanja , Berendsen Johanna T. W. , Kruit Stella A. , Broekhuijse Marleen L. W. J. , Segerink Loes I.
Published: August 2020

The use of microfluidics in artificial reproductive technologies for manipulation or assessment of spermatozoa is unique in the sense that it is not always an end point measurement and the sample may be used afterward. During microfluidic processing, spermatozoa are exposed to shear stress, which may harm viability and functioning of spermatozoa. The shear stresses during general microfluidic processing steps were calculated and compared to estimated shear stresses during ejaculation. The viability of boar and bull spermatozoa after microfluidic processing was studied and compared to the typical handling method (centrifugation) and to a control (the sample in a tube at the same temperature). The boar spermatozoa showed a small but significant decrease in viability of 6% after microfluidic handling. Bull spermatozoa proved to be less susceptible to shear stress and were not significantly affected by microfluidic processing. These data indicate that the impact of microfluidic processing on the viability of boar and bull spermatozoa is less than the literature values reported for flow cytometry and comparable to the impact of centrifugation.
InGaAs/InP single-photon detectors with 60% detection efficiency at 1550 nm
Authors: Fang Yu-Qiang , Chen Wei , Ao Tian-Hong , Liu Cong , Wang Li , Gao Xin-Jiang , Zhang Jun , Pan Jian-Wei
Published: August 2020

InGaAs/InP single-photon detectors (SPDs) are widely used for near-infrared photon counting in practical applications. Photon detection efficiency (PDE) is one of the most important parameters for SPD characterization, and therefore, increasing PDE consistently plays a central role in both industrial development and academic research. Here, we present the implementation of high-frequency gating InGaAs/InP SPDs with a PDE as high as 60% at 1550 nm. On one hand, we optimize the structure design and device fabrication of InGaAs/InP single-photon avalanche diodes with an additional dielectric–metal reflection layer to relatively increase the absorption efficiency of incident photons by ∼20%. On the other hand, we develop a monolithic readout circuit of weak avalanche extraction to minimize the parasitic capacitance for the suppression of the afterpulsing effect. With 1.25 GHz sine wave gating and optimized gate amplitude and operation temperature, the SPD is characterized to reach a PDE of 60% with a dark count rate (DCR) of 340 kcps. For practical use, given 3 kcps DCR as a reference, the PDE reaches ∼40% PDE with an afterpulse probability of 5.5%, which can significantly improve the performance for the near-infrared SPD-based applications.
Double excitation multi-stability and multi-pulse chaotic vibrations of a bistable asymmetric laminated composite square panels under foundation force
Authors: Zhang W. , Ma W. S. , Zhang Y. F. , Liu Y. Z.
Published: August 2020

The double excitation multi-stability and Shilnikov-type multi-pulse jumping chaotic vibrations are analyzed for the bistable asymmetric laminated composite square panel under foundation force for the first time. Based on the extended new high-dimensional Melnikov function, the explicit sufficient conditions are obtained for the existence of the Shilnikov-type multi-pulse jumping homoclinic orbits and chaotic vibrations in the bistable asymmetric laminated composite square panel, which implies that multi-pulse jumping chaotic vibrations may occur in the sense of Smale horseshoes. The extended new high-dimensional Melnikov function gives the parameters domain of the intersection for the homoclinic orbits, which illustrates the relationship among the coefficients of damping, parametric, and external excitations. Numerical simulations including the bifurcation diagrams, largest Lyapunov exponents, phase portraits, waveforms, and Poincaré sections are utilized to study the double excitation multi-pulse jumping and metastable chaotic vibrations and dynamic snap-through phenomena. The numerical results demonstrate that double excitation Shilinikov multi-pulse jumping chaotic and small metastable chaotic vibrations coexist in the bistable asymmetric laminated composite square panel. It is found that the external excitation changes the complexity of the chaos, while the parameter excitation changes the type of chaos. It is verified that the bistable asymmetric laminated composite square panel with small damping is easier to produce double excitation Shilinikov multi-pulse jumping chaotic vibrations.
New method for solving strong conservative odd parity nonlinear oscillators: Applications to plasma physics and rigid rotator
Authors: Hammad Ma’mon Abu , Salas Alvaro H. , El-Tantawy S. A.
Published: August 2020

In the present work, a new method for solving a strong nonlinear oscillator equation of the form ẍ + F(x) = 0, where F(−x) = −F(x), is carried out. This method consists of approximating function F(x) by means of a suitable Chebyshev polynomial: F(x) ≈ P(x) = px + qx3 + rx5, and then, the original oscillator is replaced by the cubic–quintic Duffing equation ẍ + px + qx3 + rx5 = 0 with arbitrary initial conditions, which admits the exact solution in terms of elliptic functions. The efficacy of the present method is demonstrated through the fluid multi-ion plasma equations and a generalized pendulum problem. For the generalized pendulum problem, the governing motion is directly reduced to the cubic–quintic Duffing oscillator with the help of the Chebyshev polynomial, and the approximate analytical and exact solutions are obtained. In addition, the comparison between our solutions and the Runge–Kutta numerical solution is examined. Moreover, the periodic time formula of the oscillations for both the approximate analytical solution and the exact solution is deduced, and the comparison between them is implemented. With respect to the plasma application, the fluid plasma equations of its particles are reduced to the Extended Korteweg–de Vries (EKdV) equation utilizing a reductive perturbation method. Then, we proved for the first time that any undamped polynomial oscillator of the nth degree can be reduced to a (2n − 1)th odd parity Duffing. Accordingly and after applying the previous theory to the EKdV equation, it was converted to the cubic–quintic Duffing equation. Finally, we can deduce that our new solutions and theory help us to understand and investigate many nonlinear phenomena in various branches of science.
Vibrational relaxation time measurements in shock-heated oxygen and air from 2000 K to 9000 K using ultraviolet laser absorption
Authors: Streicher Jesse W. , Krish Ajay , Hanson Ronald K.
Published: August 2020

Vibrational relaxation times of oxygen (O2) were measured behind reflected shocks in shock-tube experiments with O2 and nitrogen (N2) collision partners. To determine relaxation times, a tunable ultraviolet laser absorption diagnostic probed time-histories involving the fourth (v″ = 4), fifth (v″ = 5), and sixth (v″ = 6) vibrational levels of the ground electronic state of O2. Taking the ratio of two absorbance time-histories involving different vibrational levels yielded vibrational temperature time-histories that were fit to isolate the relevant vibrational relaxation times. Pure O2 experiments were used to isolate the vibration–translation (VT) relaxation time of O2 with O2. Results for τVTO2–O2 agree with the Millikan and White correlation at temperatures below 4000 K. However, high-temperature data deviate from the Millikan and White correlation, exhibiting a reduced temperature dependence—an observation that remains consistent with previous experimental studies. Additional experiments in 10% and 21% O2 in N2 mixtures were used to isolate both the VT and vibration–vibration (VV) relaxation times of O2 with N2. The data for τVTO2–N2 exceed the Millikan and White correlation by 70% but show reasonable agreement with previous data below 5000 K. High-temperature results again show a reduced temperature dependence, but this study shows longer relaxation times than the previous work. The data for τVVO2–N2 exceed the semi-empirical relation developed by Berend et al. [“Vibration-vibration energy exchange in N2 with O2 and HCl collision partners,” J. Chem. Phys. 57, 3601–3604 (1972)] by 70% but overlap with previous measurements. Due to insensitivity of the chemical system to VV transfer at high temperatures, results for τVVO2–N2 were only measured below 6000 K.
Heralded spectroscopy with a fiber photon-pair source
Authors: Pearce E. , Phillips C. C. , Oulton R. F. , Clark A. S.
Published: August 2020

The correlations between photons generated by nonlinear optical processes offer advantages for many quantum technology applications, including spectroscopy, imaging, and metrology. Here, we use spontaneous four-wave mixing in a birefringent single-mode fiber pumped by a tunable pulsed laser as a broadly tunable source of phase-matched non-degenerate photon pairs for spectroscopy. The pairs are tunable such that the idler beam measures the transmittance spectrum of a sample in the near infrared, while the visible signal beam independently reports correlation information. By the time-resolved counting of both signal and idler photons, we use photon-number correlations to remove uncorrelated noise from the probe beam. Here, we have used heralded spectroscopy to measure the absorption spectrum of gallium arsenide near its band edge, despite the idler photon spectrum being dominated by a large background from spontaneous Raman scattering.
Anomalous domains formed under AFM-TIP voltages in Sr0.61Ba0.39Nb2O6 crystals and their suppression
Authors: Volk T. R. , Bodnarchuk Ya. V. , Gainutdinov R. V. , Ivleva L. I.
Published: August 2020

Submicro- and nanosized domain patterns are demanded by various applications. The most attractive method for fabrication of structures of these scales is the domain writing by an AFM-tip voltage Utip. The use of this method is limited by the appearance of so-called anomalous domains, in which a small area under the tip is polarized oppositely to the poling field. We present the studies of anomalous domains in zero-field cooled (ZFC) and field cooled Sr0.61Ba0.39Nb2O6 crystals. A correlation between the spatial distribution of the domain shape and the bias Ub of local hysteresis loops was found in ZFC crystals, namely, in the points with a larger Ub the anomalous domains appeared at higher Utip. Based on this correlation, we managed to prevent the formation of anomalous domains by a strong preliminary poling of the crystal resulting in an essential increase in Ub all over the bulk. The dependences of the domain diameter D on Utip and the exposure time tp are described by the unique linear and power D ∼ tpk functions, respectively. These dependences are not affected by the appearance of an anomalous region growing with Utip and tp.
Reduced work function and improved field emission stability of ZrC nanowires upon surface oxidation
Authors: Chiu Ta-Wei , Tang Jie , Tang Shuai , Hayami Wataru , Yuan Jinshi , Qin Lu-Chang
Published: August 2020

The field-emission characteristics of zirconium carbide (ZrC) nanowire with an oxidized surface are studied. When the ZrC nanowire is processed to introduce an oxidized surface, its field-emission performance is improved significantly, exhibiting a high field-emission current and enhanced emission current stability with a fluctuation of 1.7% in a vacuum of 6 × 10−8 Pa. Furthermore, a reduced turn-on voltage of the ZrC nanowire after oxidation was observed in the field-emission measurement, which is attributed to a reduction of the work function of the ZrC nanowire after oxidation treatment. Density functional theory calculations have also been performed to validate the mechanisms responsible for the improvement of field-emission stability and reduction in the work function of the ZrC nanowire.
A nonlinear magneto-mechanical coupling model for magnetization and magnetostriction of ferromagnetic materials
Authors: Kim Sok , Kim Kwanghun , Choe Kang , JuHyok U. , Rim Hyongchol
Published: August 2020

A new magneto-mechanical coupling model was proposed for ferromagnetic materials under applied stress and in magnetic fields. The proposed model is based on the thermodynamic theory of ferromagnetic materials and Jiles–Atherton–Sablic (J–A–S) theory with respect to the effective magnetic field. Compared with the existing models for ferromagnetic materials, the prediction results of this model are more consistent with the existing experimental results, and the prediction accuracy has been significantly improved. This model can more accurately predict the nonlinear changes in the magnetization and magnetostriction under the applied stress and magnetic field. In addition, the effects of applied stress and magnetic field on magnetization and magnetostriction of ferromagnetic materials are analyzed on the basis of magnetic domain theory. In conclusion, the proposed model can fully describe the effect of applied stress on magnetization, magnetic permeability, and magnetostrictive strain, and the effects of applied stress and magnetic field on total magnetostrictive strain (i.e., the ΔE effect); furthermore, it sufficiently reflect the nonlinear coupling properties of the magnetic field, magnetization, and magnetostriction for ferromagnetic materials under applied stress and in magnetic fields.
Raman studies of hydrogen trapped in As4O6·2H2 at high pressure and low temperature
Authors: Guńka Piotr A. , Zhu Li , Strobel Timothy A. , Zachara Janusz
Published: August 2020

Raman spectroscopic measurements of the arsenolite–hydrogen inclusion compound As4O6·2H2 were performed in diamond anvil cells at high pressure and variable temperature down to 80 K. The experimental results were complemented by ab initio molecular dynamics simulations and phonon calculations. Observation of three hydrogen vibrons in As4O6·2H2 is reported in the entire temperature and pressure range studied (up to 24 GPa). While the experiments performed with protium and deuterium at variable temperatures allowed for the assignment of two vibrons as Q1(1) and Q1(0) transitions of ortho and para spin isomers of hydrogen trapped in the inclusion compound, the origin of the third vibron could not be unequivocally established. Low-temperature spectra revealed that the lowest-frequency vibron is actually composed of two overlapping bands of Ag and T2g symmetries dominated by H2 stretching modes as predicted by our previous density functional theory calculations. We observed low-frequency modes of As4O6·2H2 vibrations dominated by H2 “librations,” which were missed in a previous study. A low-temperature fine structure was observed for the J = 0 → 2 and J = 1 → 3 manifolds of hydrogen trapped in As4O6·2H2, indicating the lifting of degeneracy due to an anisotropic environment. A non-spherical distribution was captured by molecular dynamics simulations, which revealed that the trajectory of H2 molecules is skewed along the crystallographic ⟨111⟩ direction. Last but not least, low-temperature synchrotron powder x-ray diffraction measurements on As4O6·2H2 revealed that the bulk structure of the compound is preserved down to 5 K at 1.6 GPa.
Impact of a small disk on a sessile water drop
Authors: Bazilevsky A. V. , Rozhkov A. N.
Published: August 2020

We address the details of events that follow the impact of a small solid disk on a water drop sitting on another disk of the same diameter. We experimentally demonstrate that fast squeezing of a low-viscosity liquid drop between two approaching disks leads to the formation of complex, radially expanding liquid structures (splashes) outside of the disks. The spatial and temporal dynamics of these splashes are tracked via high-speed video recording and flash photography. We analyze the mechanisms that control the shapes and breakup processes of these structures and derive a mathematical model for their behavior using simple physical arguments. Our investigation indicates that liquid structure formation is the result of a rapid increase in the velocity of liquid ejection from the gap between disks with time.
Linear stability of the flow of a second order fluid past a wedge
Authors: Cracco M. , Davies C. , Phillips T. N.
Published: August 2020

The linear stability analysis of Rivlin–Ericksen fluids of second order is investigated for boundary layer flows, where a semi-infinite wedge is placed symmetrically with respect to the flow direction. Second order fluids belong to a larger family of fluids called order fluids, which is one of the first classes proposed to model departures from Newtonian behavior. Second order fluids can model non-zero normal stress differences, which is an essential feature of viscoelastic fluids. The linear stability properties are studied for both signs of the elasticity number K, which characterizes the non-Newtonian response of the fluid. Stabilization is observed for the temporal and spatial evolution of two-dimensional disturbances when K > 0 in terms of increase of critical Reynolds numbers and reduction of growth rates, whereas the flow is less stable when K < 0. By extending the analysis to three-dimensional disturbances, we show that a positive elasticity number K destabilizes streamwise independent waves, while the opposite happens for K < 0. We show that, as for Newtonian fluids, the non-modal amplification of streamwise independent disturbances is the most dangerous mechanism for transient energy growth, which is enhanced when K > 0 and diminished when K < 0.
Different time scales in dynamic systems with multiple outcomes
Authors: Bel G. , Zilman A. , Kolomeisky A. B.
Published: August 2020

Stochastic biochemical and transport processes have various final outcomes, and they can be viewed as dynamic systems with multiple exits. Many current theoretical studies, however, typically consider only a single time scale for each specific outcome, effectively corresponding to a single-exit process and assuming the independence of each exit process. However, the presence of other exits influences the statistical properties and dynamics measured at any specific exit. Here, we present theoretical arguments to explicitly show the existence of different time scales, such as mean exit times and inverse exit fluxes, for dynamic processes with multiple exits. This implies that the statistics of any specific exit dynamics cannot be considered without taking into account the presence of other exits. Several illustrative examples are described in detail using analytical calculations, mean-field estimates, and kinetic Monte Carlo computer simulations. The underlying microscopic mechanisms for the existence of different time scales are discussed. The results are relevant for understanding the mechanisms of various biological, chemical, and industrial processes, including transport through channels and pores.
Based on damage caused by microstructure evolution during long-term thermal exposure to analyze and predict creep behavior of Ni-based single crystal superalloy
Authors: Gan Wenyan , Gao Hangshan , Wen Zhixun
Published: August 2020

The creep rupture life of a Ni-based single-crystal superalloy was evaluated under 980 °C/270 MPa after the superalloy was thermally exposed to temperatures of 900 °C, 950 °C, and 1100 °C for 100 h–500 h. The results showed that the coarsening rate of the γ′ phase increased with the thermal exposure temperature, and the activation energy of coarsening, Q, was ∼270.9 kJ/mol; this means that element diffusion controlled the coarsening of the γ′ phase. In addition, an increase in the thermal exposure temperature accelerated the precipitation process of the topologically close-packed (TCP) phase. Because of the degradation of the microstructure, the creep rupture life decreased from 113 h after thermal exposure at 900 °C to 95 h after exposure at 950 °C, and finally to 29 h after exposure at 1100 °C when exposed for 500 h. In view of the experimental results, the influence of the microstructure evolution on the creep rupture life was investigated in detail. Finally, a creep constitutive model based on the dislocation density was combined with a continuous damage model that considers the cavity damage to obtain a creep damage model. The creep remaining life prediction model of the single-crystal superalloy was established to predict the remaining life by introducing initial damage terms (the damage caused by the coarsening of the γ′ phase and that caused by the precipitation of the TCP phase during long-term thermal exposure, ωγ′ and ωTCP, respectively) to the creep damage model.
Transport and deposition of dilute microparticles in turbulent thermal convection
Authors: Xu Ao , Tao Shi , Shi Le , Xi Heng-Dong
Published: August 2020

We analyze the transport and deposition behavior of dilute microparticles in turbulent Rayleigh–Bénard convection. Two-dimensional direct numerical simulations were carried out for the Rayleigh number (Ra) of 108 and the Prandtl number (Pr) of 0.71 (corresponding to the working fluids of air). The Lagrangian point particle model was used to describe the motion of microparticles in the turbulence. Our results show that the suspended particles are homogeneously distributed in the turbulence for the Stokes number (St) less than 10−3, and they tend to cluster into bands for 10−3 ≲ St ≲ 10−2. At even larger St, the microparticles will quickly sediment in the convection. We also calculate the mean-square displacement (MSD) of the particle’s trajectories. At short time intervals, the MSD exhibits a ballistic regime, and it is isotropic in vertical and lateral directions; at longer time intervals, the MSD reflects a confined motion for the particles, and it is anisotropic in different directions. We further obtained a phase diagram of the particle deposition positions on the wall, and we identified three deposition states depending on the particle’s density and diameter. An interesting finding is that the dispersed particles preferred to deposit on the vertical wall where the hot plumes arise, which is verified by tilting the cell and altering the rotation direction of the large-scale circulation.
Electroresistance and electro-optic effects in molecular ferroelectrics
Authors: Hu Yong , Ren Shenqiang
Published: August 2020

Molecular ferroelectrics are often considered as an alternative to inorganic ferroelectrics due to their structural diversity, optical transparency, and low-temperature solution processing. A significant amount of molecular ferroelectrics have been developed and studied for their fundamental mechanisms and potential applications in electronic devices. This review will report the recent findings in the study of electroresistance and electro-optic effects based on molecular ferroelectrics. Different varieties of molecular ferroelectrics are discussed according to their electronic structure and related electroresistance and electro-optic effects. We sketch the current theoretical understanding of electroresistance and electro-optic effects in molecular ferroelectrics, summarize key experimental results, and outline promising prospects in future molecular electronic devices.
Application of the Variable Oxygen Probe to Derivatives of 2,6-Dimethyltetrahydropyran-4-ol: Evidence for Through-Bond nO–σCC–σ*CO Interactions
Authors: Oliver Liam , Ragam Somaiah , Deslongchamps Pierre , White Jonathan M. , Hancock Amber , Brydon Samuel
Published: August 2020

The variable oxygen probe has been applied to axial and equatorial 4-pyranols 4 and 5 and their ester and ether derivatives. Plots of C–OR bond distance versus pKa (ROH) provided evidence for slightly stronger donation into the σ*C–OR antibonding orbital in the equatorial derivatives 5 than in the axial derivatives 4, which is consistent with the presence of a through-bond nO–σCC–σ*CO interaction in 5. Evidence in support of this interpretation was also provided by density functional theory (DFT) calculations and natural bond orbital (NBO) analyses of the various orbital interactions in the 4-pyranols 4 and 5, their protonated analogues 4·H2O+ and 5·H2O+, and the corresponding cyclohexane derivatives 6, 7, 6·H2O+, and 7·H2O+.
Ageing badly: indicators of old-age structure in Australia and New Zealand
Authors: Barak Yoram , Neehoff Shona , Glue Paul
Published: August 2020

ABSTRACT
INTRODUCTIONUntil 2050, Australia and New Zealand will experience continuing increase in the population aged >65 years. Studying differences in indicators of old-age structure between these countries can inform policymakers.
AIMTo calculate and analyse indicators of old-age structure for Australia and New Zealand.
METHODSFive indicators of old-age structure were calculated: centenarian ratio (number of centenarians per 100,000 people), longevity index (proportion of people aged ≥90 and ≥65 years in the population), longevity level (proportion of 80+/60+ years population), ageing tendency (proportion of people aged ≥60 years in the population) and centenarity index (ratio between the centenarians and the total population ≥90 years).
RESULTSAll indicators of old-age structure demonstrated an advantageous ageing structure in Australia compared with New Zealand. In addition, the New Zealand Māori and Australian Aboriginal indicators of old-age structure demonstrated a significant disadvantage to these ethnic groups compared with the general population.
DISCUSSIONPublic health policy needs to target ageing in New Zealand as a major goal in advancing the ‘Ageing Well’ policy advocated by the government.
Fiber optic Fabry–Perot interferometer constructed by quartz capillary and titanium wire for temperature measurement
Authors: Liao Jie , Feng Wenlin , Yang Xiaozhan
Published: August 2020

A novel fiber temperature sensing head based on the Fabry–Perot interference principle is proposed and fabricated. Its temperature sensing is performed by using the thermal expansion of titanium wire fixed in a quartz capillary. The rationality of ignoring high-order reflected light was verified by the experiment. The spectra of heating and cooling processes were measured for three times in the temperature range of 1 ∼ 50 °C, showing the high consistency and stability. This sensor requires only 25 nm scanning width of the optical spectrum analyzer. Its sensitivity of the Fabry–Perot cavity optical length changing with temperature is approximately −66.7 nm °C−1, and the accuracy can reach 0.1 °C by utilizing the binomial empirical formula instead of the linear one.
Initial evaluation and analysis of NRTK positioning performance with new BDS-3 signals
Authors: Liu Jinhai , Tu Rui , Han Junqiang , Zhang Rui , Fan Lihong , Zhang Pengfei , Hong Ju , Lu Xiaochun
Published: August 2020

In 2018, China established the primary constellation of the BeiDou-3 global navigation satellite system (BDS-3), and the construction of this satellite system is due to be completed in 2020. The signal emitted by BDS-3 will provide global positioning, navigation and timing services. This study assessed the performance of network real-time kinematic (NRTK) in reference to the new BDS-3 signals. The ambiguity resolution, retrieval, and interpolation of the double-differenced (DD) observation corrections and positioning precision are assessed based on datasets collected using four SR480 receivers that track the open signals of BDS-3. Subsequently, the NRTK, using the combined BDS-2 and BDS-3 measurements, is compared with the NRTK using only BDS-2 measurements. In addition, the positioning results of NRTK are compared with those of RTK. The results show that the DD atmospheric delay corrections with centimeter-level accuracy can be derived from the network of regional reference stations, and the positioning accuracy of NRTK is improved by incorporating the BDS-3 measurements.
Developing printable thermoelectric materials based on graphene nanoplatelet/ethyl cellulose nanocomposites
Authors: Mardi Saeed , Risi Ambrogioni Marco , Reale Andrea
Published: August 2020

Thermoelectric (TE) materials have drawn a lot of attention as a promising technology to harvest waste heat and convert it into electrical energy. However, the toxicity and expense of inorganic TE materials along with high-temperature fabrication processes have limited their application. Additionally, the reduction of raw material resources, such as metals and petroleum is another limiting factor. Hence, developing low-cost, stable, and easily-created TE materials from renewable resources is attracting more and more interest for a wide range of applications including the internet of things and self-powered sensors. Herein, an efficacious processing strategy to fabricate printable TE materials has been developed with Ethyl cellulose (EC), a non-conducting polymer, as the polymer matrix and with Graphene nanoplatelets (GNPs) as fillers. EC, one of the cellulose’s derivatives, has been widely used as a binder in the printing pastes. The conductive pastes with different filler contents have been fabricated. The weight ratio of GNPs and EC were ranged from 0.2 to 0.7. These conductive pastes have been deposited by blade coating on glass substrates. The electrical conductivity of the composites has increased polynomially as the filler content increased, whereas the Seebeck coefficient did not change significantly with the increased electrical conductivity. The highest electrical conductivity at room temperature (355.4 S m−1) was obtained for the ratio of 0.7. This ratio also had the maximum power factor value. Moreover, a 3D structure form (cylindrical pellet) from the highest conductive paste was also fabricated. The proposed technique demonstrates an industrially feasible approach to fabricate different geometries and structures for organic TE modules. So, this approach could provide a good reference for the production of high efficiency, low-temperature, lightweight, low-cost, TE materials.
Clinical Validation and Performance Evaluation of the Automated Vitros Total Anti–SARS-CoV-2 Antibodies Assay for Screening of Serostatus in COVID-19
Authors: Garnett Emily , Jung Joanna , Tam Estella , Rajapakshe Deepthi , Cheney Stephen , Brown Cameron , Cao Jing , Muldrew Kenneth , Singh Ila , Versalovic James , Devaraj Sridevi
Published: August 2020

Objectives

Evaluation of serostatus against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as an important tool in identification of exposure to coronavirus disease 2019 (COVID-19). We report on the validation of the Vitros Anti–SARS-CoV-2 Total (CoV2T) assay for qualitative serologic testing of SARS-CoV-2 antibodies.

Methods

We performed validation studies according to Commission of Office Laboratories Accreditation guidelines, using samples previously tested for SARS-CoV-2 by reverse transcription–polymerase chain reaction (RT-PCR). We evaluated precision, analytical interferences, and cross-reactivity with other viral infections; evaluated concordance with molecular and other serologic testing; and evaluated seroconversion.

Results

The Vitros CoV2T assay exhibited acceptable precision and did not exhibit cross-reactivity with other acute respiratory virus infections. The CoV2T assay exhibited 100% negative predictive agreement (56/56) and 71% positive predictive agreement (56/79) with RT-PCR across all patient samples and was concordant with other serologic assays. Concordance with RT-PCR was 97% more than 7 days after symptom onset. The CoV2T assay was robust to icterus and lipemia but had interference from significant hemolysis.

Conclusions

The Vitros CoV2T assay was successfully validated in our laboratory. We anticipate it will be a useful tool in screening for exposure to SARS-CoV-2; however, the use of the CoV2T and other serologic assays in the clinical management of patients with COVID-19 is unknown and must be evaluated in future studies.
A semi-supervised learning framework for quantitative structure–activity regression modelling
Authors: Watson Oliver , Cortes-Ciriano Isidro , Watson James A
Published: August 2020

Motivation

Quantitative structure–activity relationship (QSAR) methods are increasingly used in assisting the process of preclinical, small molecule drug discovery. Regression models are trained on data consisting of a finite-dimensional representation of molecular structures and their corresponding target-specific activities. These supervised learning models can then be used to predict the activity of previously unmeasured novel compounds.

Results

This work provides methods that solve three problems in QSAR modelling: (i) a method for comparing the information content between finite-dimensional representations of molecular structures (fingerprints) with respect to the target of interest, (ii) a method that quantifies how the accuracy of the model prediction degrades as a function of the distance between the testing and training data and (iii) a method to adjust for screening dependent selection bias inherent in many training datasets. For example, in the most extreme cases, only compounds which pass an activity-dependent screening threshold are reported. A semi-supervised learning framework combines (ii) and (iii) and can make predictions, which take into account the similarity of the testing compounds to those in the training data and adjust for the reporting selection bias. We illustrate the three methods using publicly available structure–activity data for a large set of compounds reported by GlaxoSmithKline (the Tres Cantos AntiMalarial Set, TCAMS) to inhibit asexual in vitro Plasmodium falciparum growth.

Availabilityand implementation

https://github.com/owatson/PenalizedPrediction.

Supplementary information

Supplementary data are available at Bioinformatics online.
Severe fires alter the outcome of the mutualism between ants and a Neotropical savanna tree
Authors: Vasconcelos Heraldo L , Koch Elmo B A , Camarota Flávio , Tito Richard , Zuanon Lino A , Maravalhas Jonas
Published: August 2020

Physical disturbances, such as fire, may affect the relationship between ants and plants. We evaluated the extent to which severe fires alter the protective effect of ants against the herbivores of an extrafloral-nectary bearing tree. We performed an ant removal experiment and sampled the ant fauna from the same trees over 4 years: the pre-fire year, the fire-year, and again 1 and 2 years later. Ants reduced insect herbivory in the pre-fire year and in the fire-year but failed to provide any plant protection in the two years after fire. The magnitude of the ant effect on herbivory did not differ between the pre-fire year and the fire-year. Fire reduced the abundance of ants with strictly arboreal-nesting habits. However, in the fire year (but not in the subsequent ones), this decline was compensated by an increase in the abundance of arboreal generalists and ground-nesting ants foraging in trees. Our results indicate that severe fires can affect the strength and direction of the ant effects on herbivory by altering the structure of the arboreal ant community and the abundance of insect herbivores. Fire disturbance is thus an important factor of conditionality of ant-plant mutualisms in fire-prone habitats, like the Cerrado savannas.
Carryover effects and the evolution of polyphenism
Authors: de la Serna Buzon Sofia M , Martin Ryan A , Pfennig David W
Published: August 2020

An individual’s early-life environment and phenotype often influence its traits and performance as an adult. We investigated whether such ‘carryover effects’ are associated with alternative, environmentally-induced phenotypes (‘polyphenism’), and, if so, whether they influence the evolution of polyphenism. To do so, we studied Mexican spadefoot toads, Spea multiplicata, which have evolved a polyphenism consisting of two, dramatically different forms: a carnivore morph and an omnivore morph. We sampled both morphs from a fast-drying and a slow-drying pond and reared them to sexual maturity. Larval environment (pond) strongly influenced survival as well as age and size at metamorphosis and sexual maturity; i.e. environment-dependent carryover effects were present. By contrast, larval phenotype (morph) did not affect life-history traits at sexual maturity; i.e. phenotype-dependent carryover effects were absent. These results are consistent with theory, which suggests that by amplifying selective trade-offs in heterogenous environments, environment-dependent carryover effects might foster the evolution of polyphenism. At the same time, by freeing selection to refine a novel phenotype without altering the existing form, the absence of phenotype-dependent carryover effects might enable polyphenism to evolve in the first place. Generally, carryover effects might play an underappreciated role in the evolution of polyphenism.
Comparative leaf micromorphology ofDrypetesandPutranjiva(Putranjivaceae) and its taxonomic significance
Authors: Kadiri Akeem B , Muellner-Riehl Alexandra N
Published: August 2020

Putranjivaceae are a pantropically distributed but poorly known glucosinulate-producing family of three genera (Drypetes, Putranjiva and Sibangea), previously included in Euphorbiaceae subfamily Phyllanthoideae. Characters of the leaf epidermis were previously suggested as being of infrafamilial taxonomic relevance, but epidermal features of the three genera have not so far been compared in the light of the phylogenetic relationships recovered by molecular data. Therefore, we compared the leaf micromorphology of 44 (out of c. 200) Drypetes spp. and two (out of three) Putranjiva spp. using light microscopy. Our findings revealed that there are more stomata types than previously reported in both genera. We also present a new record of stomatal complexes and epidermal cell characteristics. The cell wall ornamentation character on both surfaces of the epidermis is useful for distinguishing D. aframensis subsp. aframensis. Based on a combination of the studied characters, doubtful species of Drypetes and Putranjiva are recognizable as belonging to the two genera, and this will require taxonomic and nomenclatural adjustments. Other taxonomically useful characters are trichome distribution and types and leaf areole shape and tertiary veins branching patterns that appear to be relatively constant across the two genera. Oil droplets located within the cell lumen in Putranjiva differentiates it from Drypetes, where they inwardly streak the epidermal walls among other features. Thus, our study provides evidence that the investigated leaf micromorphological characters are useful for distinguishing the species of the two genera, and they corroborate the existing infrageneric classification of Drypetes that was based on exomorphology.
Genetic, cellular, and connectomic characterization of the brain regions commonly plagued by glioma
Authors: Mandal Ayan S , Romero-Garcia Rafael , Hart Michael G , Suckling John
Published: August 2020

For decades, it has been known that gliomas follow a non-random spatial distribution, appearing more often in some brain regions (e.g. the insula) compared to others (e.g. the occipital lobe). A better understanding of the localization patterns of gliomas could provide clues to the origins of these types of tumours, and consequently inform treatment targets. Following hypotheses derived from prior research into neuropsychiatric disease and cancer, gliomas may be expected to localize to brain regions characterized by functional hubness, stem-like cells, and transcription of genetic drivers of gliomagenesis. We combined neuroimaging data from 335 adult patients with high- and low-grade glioma to form a replicable tumour frequency map. Using this map, we demonstrated that glioma frequency is elevated in association cortex and correlated with multiple graph-theoretical metrics of high functional connectedness. Brain regions populated with putative cells of origin for glioma, neural stem cells and oligodendrocyte precursor cells, exhibited a high glioma frequency. Leveraging a human brain atlas of post-mortem gene expression, we found that gliomas were localized to brain regions enriched with expression of genes associated with chromatin organization and synaptic signalling. A set of glioma proto-oncogenes was enriched among the transcriptomic correlates of glioma distribution. Finally, a regression model incorporating connectomic, cellular, and genetic factors explained 58% of the variance in glioma frequency. These results add to previous literature reporting the vulnerability of hub regions to neurological disease, as well as provide support for cancer stem cell theories of glioma. Our findings illustrate how factors of diverse scale, from genetic to connectomic, can independently influence the anatomic localization of brain dysfunction.
Microbial Inoculants Differentially Influence Plant Growth and Biomass Allocation in Wheat Attacked by Gall-Inducing Hessian Fly (Diptera: Cecidomyiidae)
Authors: Prischmann-Voldseth Deirdre A , Özsisli Tülin , Aldrich-Wolfe Laura , Anderson Kirk , Harris Marion O
Published: August 2020

Beneficial root microbes may mitigate negative effects of crop pests by enhancing plant tolerance or resistance. We used a greenhouse experiment to investigate impacts of commercially available microbial root inoculants on growth and biomass allocation of wheat (Triticum aestivum L. [Cyperales: Poaceae]) and on survival and growth of the gall-inducing wheat pest Hessian fly, Mayetiola destructor (Say). A factorial design was used, with two near-isogenic wheat lines (one susceptible to Hessian fly, the other resistant), two levels of insect infestation (present, absent), and four inoculants containing: 1) Azospirillum brasilense  Tarrand et al. (Rhodospirillales: Azospirillaceae), a plant growth-promoting bacterium, 2) Rhizophagus intraradices (N.C. Schenck & G.S. Sm.) (Glomerales: Glomeraceae), an arbuscular mycorrhizal fungus, 3) A. brasilense + R. intraradices, and 4) control, no inoculant. Larval feeding stunted susceptible wheat shoots and roots. Plants had heavier roots and allocated a greater proportion of biomass to roots when plants received the inoculant with R. intraradices, regardless of wheat genotype or insect infestation. Plants receiving the inoculant containing A. brasilense (alone or with R. intraradices) had comparable numbers of tillers between infested and noninsect-infested plants and, if plants were susceptible, a greater proportion of aboveground biomass was allocated to tillers. However, inoculants did not impact density or performance of Hessian fly immatures or metrics associated with adult fitness. Larvae survived and grew normally on susceptible plants and mortality was 100% on resistant plants irrespective of inoculants. This initial study suggests that by influencing plant biomass allocation, microbial inoculants may offset negative impacts of Hessian flies, with inoculant identity impacting whether tolerance is related to root or tiller growth.
Case series of high-risk percutaneous coronary intervention with rotational atherectomy under short-term mechanical circulatory support with TandemHeart in the setting of acute myocardial infarction
Authors: Großekettler Leonie , Schmack Bastian , Katus Hugo A , Bekeredjian Raffi , Raake Philip
Published: August 2020

Background 

TandemHeart is a percutaneous Ventricular Assist Device, most commonly used to provide mechanical circulatory support during high-risk percutaneous coronary intervention and postcardiotomy cardiac failure. However, TandemHeart has not been applied in patients with severe heart failure due to myocardial infarction during high-risk percutaneous coronary intervention with the need for rotational artherectomy (RA) before, so we present a first-in-man case series.

Case summary 

Three patients with severe HF[Please spell out HF, LA and MI (if necessary).] due to acute myocardial infarction revealed severely calcified lesions of the unprotected left main artery. We successfully used the TandemHeart as percutaneous Ventricular Assist Device during high-risk percutaneous coronary intervention with RA.

Discussion 

We here report our experience and show that RA under TandemHeart mechanical circulatory support is feasible and safe in case of acute MI.
The Sermon as a Multimedial Instrument of Communication in the Polish–Lithuanian Commonwealth During the Reformation and Counter-Reformation
Authors: Stančiene Dalia Marija
Published: August 2020

At the end of the sixteenth century, during the Christianization of Lithuania, sermons became one of the most important means of communication. As a medium, the sermon functioned through systems of codified sounds and symbols, as well as representing the institution of the Church for which it served as a means of broadcasting. Increased attention to the sermon was prompted by the desire of the Catholic Church to resist the Reformation and to preserve its spiritual monopoly. Martin Luther and Erasmus of Rotterdam underlined the importance of preaching, claiming that preaching the Gospels could improve society. The Jesuits instructed preachers not to limit themselves to religious matters alone but also to pay attention to social and political problems. There were two kinds of sermon: one for churchmen, preached in Latin; the other for lay people, in the vernacular. The Jesuits trained priests to preach in Lithuanian.
16. The Europeanization of Member State Policy
Authors: Radaelli Claudio M.
Published: August 2020

How are the policies of the member states affected by their membership of the European Union? What are the concepts and explanations in this field? Can Europeanization be reversed? This chapter examines the effects of the the public policy functions of European Union on domestic policy. It introduces the relevant concepts, and then illustrates types and modes of Europeanization. On balance, we find that the Europeanization processes have not created homogeneity or policy convergence. Rather, the Europeanization effect is differential: it differs by policy area and political system. And there are good theoretical reasons for this, grounded in the causal theories addressing the question how the EU affects domestic policy via adaptational pressure and/or domestic agency. Finally, the chapter explores a question raised by the decision of the UK to leave the EU and in diverse ways by the attempts to de-regulate or reverse the overall domestic burden of EU regulations. These categories of decisions, initiatives, and policies can be called de-Europeanization or Europeanization in reverse gear. We therefore appraise the prospect for significant de-Europeanization. The pressures for de-Europeanization are strong, but the EU regulatory regime is certainly resilient. For sure we have not seen a bonfire of EU regulations, although Europeanization effects can be reduced by withdrawing proposals or by reducing the stringency of implementation requirements.