bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum tunneling in low-dimensional semiconductors mediated by virtual photons
Authors: Martín-Palma Raúl J.
Published: January 2020

Quantum tunneling, a phenomenon that has no counterpart in classical physics, is the quantum-mechanical process by which a microscopic particle can transition through a potential barrier even when the energy of the incident particle is lower than the height of the potential barrier. In this work, a mechanism based on electron/hole annihilation and creation with the participation of virtual photons is proposed as an alternative to explain quantum tunneling processes in semiconductors. Finally, tunneling times are discussed within the proposed framework.
High operating temperature InAsSb-based mid-infrared focal plane array with a band-aligned compound barrier
Authors: Deng Gongrong , Yang Wenyun , Zhao Peng , Zhang Yiyun
Published: January 2020

In this work, by utilizing a band-aligned AlAs0.08Sb0.92/AlSb-based unipolar compound barrier design, a high-operability (∼99.7%) InAsSb bulk absorber-based mid-wavelength infrared 640 × 512 focal plane array (with a 50% cut-off wavelength at 4.1 μm at 150 K) exhibiting distinct infrared images from 150 K up to 205 K has been achieved, which suggests great potential for high operation temperature detection applications. At 150 K and −400 mV bias, the photodetectors exhibit a low dark current density of ∼3.9 × 10−6 A∕cm2, a quantum efficiency of 65.1% at peak responsivity (∼3.8 μm), and a specific detectivity of 1.73 × 1012 Jones. From 150 to 185 K, the focal plane array exhibits ∼30.2 mK and ∼69.5 mK noise equivalent temperature difference values by using f/2.0 optics and 6.45 ms and 0.61 ms integration times, respectively.
A reflective multilayer polarization converter with switchable frequency band
Authors: Li You , Wang Yi , Cao Qunsheng
Published: January 2020

A multilayer polarization converter operating in the reflection mode with a switchable frequency band is proposed, where the unit cell consists of layers of a polarizer, active frequency selective surface (AFSS), and metallic ground, separately. The polarizer layer is designed in the form of a periodic split circular loop structure. The AFSS layer is constructed by a three-layer second-order passband structure with PIN diodes loaded orthogonally on the top and bottom layers. In this design, the AFSS can be switched between the transmission and reflection modes by controlling the bias, resulting in a change in the effective permittivity of the dielectric substrate. The switchable polarization converter is verified by both simulations and experimental results. It is found that when the PIN diodes are in the ON/OFF-state, the proposal converter can change the linearly polarized wave from 9 GHz to 17.1 GHz and from 5.5 GHz to 11.6 GHz, respectively.
Controlled spin-torque driven domain wall motion using staggered magnetic wires
Authors: Mohammed H. , Risi S. Al , Jin T. L. , Kosel J. , Piramanayagam S. N. , Sbiaa R.
Published: January 2020

Domain wall (DW) memory devices such as racetrack memory offer an alternative to the hard disk drive in achieving high capacity storage. In DW memory, the control of domain wall positions and their motion using spin-transfer torque is an important challenge. In this Letter, we demonstrate controlled domain wall motion using spin-transfer torque in staggered wires. The devices, fabricated using electron-beam and laser lithography, were tested using magneto-optical Kerr microscopy and electrical transport measurements. The depinning current is found to depend on the device dimensions of the staggering wires. Thus, the proposed staggering configuration can be utilized to fine-tune the properties of DW devices for memory applications.
Doping induced charge density wave in monolayer TiS2 and phonon-mediated superconductivity
Authors: Liao Ji-Hai , Zhao Yin-Chang , Zhao Yu-Jun , Yang Xiao-Bao , Chen Yue
Published: January 2020

Using the first-principles calculations, we have investigated the effects of the charge doping and biaxial strain on the charge density wave (CDW) of monolayer octahedral titanium disulfide (1T-TiS2). Our results show that proper electron doping can suppress the (2×2) CDW instability and the larger electron doping promotes a (7×3) CDW phase involving a spontaneous breaking of the hexagonal crystal symmetry. Strain can affect the stability of doped monolayer 1T-TiS2, but neither compressive strain nor tensile strain alone can stabilize the pristine one. When TiS2 layers are decorated by metal atoms, such as Li, Na, K, Ca, and Al, the transferred charge can also suppress the (2×2) CDW instability. The stable doped 1T-TiS2 is predicted to exhibit good phonon-mediated superconductivity, which can be further enhanced by strain. Our results reveal a unique CDW phenomenon in the electron-doped monolayer 1T-TiS2 and that doping combined strain is efficient to modulate phonon softening, electron-phonon coupling, and superconductivity.
Optical frequency comb generation with low temperature reactive sputtered silicon nitride waveguides
Authors: Frigg Andreas , Boes Andreas , Ren Guanghui , Nguyen Thach G. , Choi Duk-Yong , Gees Silvio , Moss David , Mitchell Arnan
Published: January 2020

Integrated silicon nitride (SiN) waveguides with anomalous dispersion have the potential to bring practical nonlinear optics to mainstream photonic integrated circuits. However, high-stress and high-processing temperatures remain an obstacle to mass adoption. We report low-stress, high-confinement, dispersion-engineered SiN waveguides utilizing low temperature grown reactive sputtered thin-films. We demonstrate a microring resonator with an intrinsic quality factor of 6.6 × 105, which enabled us to generate a native free spectral range spaced frequency comb with an estimated on-chip pump power of 850 mW. Importantly, the peak processing temperature is 400 °C making this approach fully back-end compatible for hybrid integration with preprocessed CMOS substrates and temperature sensitive photonic platforms such as lithium niobate on insulator.
Mixed silver-nickel oxide AgNiO2: Probing by CO during XPS study
Authors: Svintsitskiy Dmitry A. , Lazarev Mikhail K. , Kardash Tatyana Yu. , Fedorova Elizaveta A. , Slavinskaya Elena M. , Boronin Andrei I.
Published: January 2020

In this work, the reaction properties of mixed silver-nickel oxide AgNiO2 were investigated in the reaction of CO oxidation ranging from room temperature up to 350 °C. X-ray photoelectron spectroscopy revealed the presence of a single oxidized silver state and the combination of Ni2+ and Ni3+ species on the surface of the as-prepared mixed oxide. It was established that AgNiO2 was able to interact with CO at room temperature. It was accompanied by the simultaneous titration of the lattice (O2−-like) and weakly charged (O−-like) oxygen species. The interaction with CO below 100 °C resulted in the accumulation of carbonate-like species on the AgNiO2 surface. Above 150 °C, the surface structure of mixed oxide was found to be disrupted, resulting in the formation of individual particles of metallic silver and oxidized nickel.
Study of motion behavior of the chains composed of micro-sized magnetic particles through a microchannel
Authors: Ling Hao , Wu Songsong , Zhu Zhijun , Zhou Jianfeng
Published: January 2020

As the chains composed of magnetic particles (MPs) move through a channel, the breaking, recomposing, and sticking to the channel wall of the chains may occur, and it is of great importance to reveal the motion regularity of magnetic nanoparticles when they are used as carriers. In this work, experimental visualizations and numerical simulations were carried out to investigate the bending phenomena of different types of chains composed of micro-sized magnetic particles in a channel flow governed by a transversal magnetic field. The experiments focus on the motion of the MP chain, and different types of chains were observed and photographed. In addition, the pose of the chains was investigated based on the lattice Boltzmann method (LBM) by using particles with diameter equal to the thickness of the chain. It is revealed that as the inlet velocity of carrier fluid increases, the bending degree of the chain increases and the regularities well coincide with the LBM simulation results. The shear force on the end particle was taken to evaluate the stability of the chain. In addition, the reorganization process of two short chains was investigated. It is feasible to model the chain composed of micro-sized MPs with large particles so as to predict the motion regularity of the chains efficiently.
Managing plasma P concentrations in beef heifers with a slow release vitamin D supplementation
Authors: Tomkins N. W. , Elliott R. , McGrath J. J. , Schatz T.
Published: January 2020

Context In extensive northern grazing systems, supplementation of P is recommended to maximise cattle growth rates and reproduction. Improving the absorption of P for the animal by influencing metabolic pathways has the potential to improve both the productivity and profitability of extensive livestock enterprises. Aims This study evaluated the efficacy of rumen bolus containing 25-hydroxyvitamin D (25OHD), commercially available as Hy-D®, and/or monensin on blood P and Ca concentrations in young cattle. Methods A total of 84 heifers, initial liveweight (mean ± s.e.m.) 184 ± 2.0 kg, were allocated to four groups, dosed with one of four slow release bolus: (1) placebo (control), (2) monensin (120 mg/day), (3) Hy-D® (6 mg/day), or (4) monensin with Hy-D®, and managed on a common unimproved native pasture from August 2012 to February 2013. On four occasions postdosing, liveweight, hip height and body condition scores were recorded, and individual faecal and jugular blood samples were collected. Key results Supplementation with monensin had a significant effect (P < 0.05) on average daily gains for the first 25 days. Interactions between 25OHD and monensin and time × monensin were also significant (P < 0.05). After 188 days, heifers receiving monensin or 25OHD + monensin were 5 and 10 kg heavier respectively, compared with their counterparts in the control and 25OHD groups. Plasma P concentrations at 25 days were 6.6 mg/dL, then increased to between 8.5 and 9.0 mg/dL and maintained this level for up to 109 days with a bolus releasing 6.0 mg/day 25OHD. Conclusions The study demonstrated that sustained and elevated plasma concentrations of both 25OHD and P, compared with control animals, can be achieved. The slow release rumen bolus maintained an elevated plasma concentration of 25OHD, and indicated that a target plasma concentration for 25OHD for increasing P absorption in beef cattle is between 200 and 300 ng/mL. Implications Supplementation of a metabolite of vitamin D influences P metabolism in Brahman heifers under grazing conditions. Integration with standard supplementation practices would optimise growth rates and reproductive performance.
Effect of carvacrol essential oils on growth performance and intestinal barrier function in broilers with lipopolysaccharide challenge
Authors: Liu S. D. , Song M. H. , Yun W. , Lee J. H. , Kim H. B. , Cho J. H.
Published: January 2020

The purpose of this study was to evaluate the effects of orally administrated carvacrol essential oils (CEOs) on the function of the intestinal barrier in broilers challenged by lipopolysaccharide (LPS). Eighty 28-day-old Ross 308 broilers were assigned to a 2 × 2 factorial arrangement of treatments (20 pens of 1 chick/treatment). Factors were CEOs (with or without orally administered) and LPS (challenged or non-challenged). Individually housed broilers were randomly assigned to four treatments (n = 20 broilers per treatment: 10 males and 10 females): no CEOs and no LPS challenge (NCEOs + NLPS); CEOs and no LPS challenge (CEOs + NLPS); no CEOs and LPS challenge (NCEOs + LPS); CEOs and LPS challenge (CEOs + LPS); all birds were fed the same diet. The broilers were administered 200 μL CEOs daily for 15 days. Orally administered CEOs significantly (P < 0.05) increased the gene expressions of occludin, claudin-1, claudin-5, zonula occludens-1 (ZO-1) and ZO-2 in the small intestinal mucosa, and increased (P < 0.05) the counts of goblet cell in the small intestinal epithelium; LPS-challenge damaged the intestinal barrier, and significantly (P < 0.05) reduced the gene expression of the aforementioned genes and increased the Escherichia coli (P < 0.05) and Salmonella enumeration (P < 0.05) in the intestine of broilers compared with the NCEOs + NLPS group. Injecting LPS reduced (P < 0.05) the gene expression of sIgA compared with the NCEOs + NLPS group. In summary, the CEOs improved the development of the intestinal barrier, to a certain extent, and repaired the intestinal damage caused by LPS.
Sesamin promotes angiogenesis and accelerates wound healing in rats via alleviates TBHP-induced apoptosis in human umbilical vein endothelial cells
Authors: Ye Sunzhi , Wang Wei , Chen Xiaoyan , Deng Yingbin
Published: January 2020

Acute stress induces tissue damage through excessive cellular apoptosis. In our study, the effects of sesamin on apoptosis and wound healing were investigated. The angiogenesis effect of sesamin was evaluated by the abilities of adherence, migration and tube formation in human umbilical vein endothelial cells (HUVECs). Our data demonstrated that treatment with sesamin dose-dependently promoted the proliferation, adherence, migration and enhanced their angiogenic ability in vitro. Moreover, the increased apoptosis in HUVECs, which stimulated by tert-butyl hydroperoxide (TBHP) was significantly attenuated by the sesamin treatment. Furthermore, we revealed that neogenesis of granulation tissue and deposition and remodeling of the collagen matrix were accelerated by the administration of sesamin in our in vivo study. These results confirm that sesamin accelerates wound healing at least partly through its antiapoptotic effects on endothelial cells at the injury site. Thus, sesamin represents a potential therapeutic medicine for vessel injury-related wounds.
Enhanced molecular yield from a cryogenic buffer gas beam source via excited state chemistry
Authors: Jadbabaie Arian , Pilgram Nickolas H , Kłos Jacek , Kotochigova Svetlana , Hutzler Nicholas R
Published: January 2020

We use narrow-band laser excitation of Yb atoms to substantially enhance the brightness of a cold beam of YbOH, a polyatomic molecule with high sensitivity to physics beyond the standard model (BSM). By exciting atomic Yb to the metastable 3P1 state in a cryogenic environment, we significantly increase the chemical reaction cross-section for collisions of Yb with reactants. We characterize the dependence of the enhancement on the properties of the laser light, and study the final state distribution of the YbOH products. The resulting bright, cold YbOH beam can be used to increase the statistical sensitivity in searches for new physics utilizing YbOH, such as electron electric dipole moment and nuclear magnetic quadrupole moment experiments. We also perform new quantum chemical calculations that confirm the enhanced reactivity observed in our experiment and compare reaction pathways of Yb(3P) with the reactants H2O and H2O2. More generally, our work presents a broad approach for improving experiments that use cryogenic molecular beams for laser cooling and precision measurement searches of BSM physics.
Single hadron multiplicities in SIDIS @ COMPASS
Authors: Bedfer Yann
Published: January 2020

Single haron multiplicities in Semi-Inclusive Deep Inelastic Scattering (SIDIS) provide an important input for the understanding of the hadronisation process and its description in terms of Fragmentation Functions (FFs). COMPASS collaboration has undertaken a programme of measurements of these observables. I first give an overview of the results obtained in the range 0.20 < z < 0.85 for the fraction z of the virtual photon energy carried by the hadron. And I then focus on the multiplicity charge ratio, h
−/h
+, at large z, which results challenge the conventional picture of a factorisation between FFs and Parton Distribution Functions (PDFs).
Physics with charmonia at the SPD experiment
Authors: Denisenko Igor
Published: January 2020

The J/ψ production is a powerful probe of hadron structure, which is complementary to other parts of the SPD physics program. In this work, the current experimental status and modern theoretical approaches to J/ψ and charmonia production are reviewed. In this context, the SPD performance and feasibility of key measurements are discussed.
Physics with prompt photons at SPD
Authors: Guskov Alexey
Published: January 2020

Prompt photons is a proven instrument for exploration of the gluonic structure of hadrons. The SPD experiment at the NICA collider plans to use prompt photons for study of the gluon contribution to the spin structure of the nucleon in the polarised proton-proton and deutron-deutron collisions.
COMPASS measurement of hard exclusive π0 muoproduction cross-section
Authors: Pešková Markéta
Published: January 2020

One of the goals of the COMPASS experimental program is the measurement of exclusive processes. The exclusive processes, such as Deep Virtual Compton Scattering (DVCS) or Hard Exclusive Meson Production, are important inputs for constraining the General Parton Distributions (GPDs). Exclusive π
0 production is the main source of background for DVCS process, while it provides important information on chiral-odd GPDs. The dedicated GPD program started with a one month pilot run in 2012, followed by two full years of data taking in 2016-2017, using 160 GeV/c positive and negative muon beams, a liquid hydrogen target and new detectors such as a recoil proton detector and a large-angle electromagnetic calorimeter. Our results of the exclusive π0 production from the 2012 pilot run, recently submitted to publication, are presented. Using average of both μ
+ and μ
− data, the γ*p cross section is extracted as a function of the squared four-momentum transfer t, and of the azimuthal angle ϕ between the scattering plane and the π
0 production plane. The average kinematics of the measurement are ⟨Q
2⟩ = 2.0 (GeV/c)2, ⟨ν⟩ = 12.8 GeV, ⟨xB
⟩ = 0.093, and ⟨−t⟩ = 0.256 (GeV/c)2. A comparison of our results with the phenomenological Goloskokov-Kroll model are shown. Prospect are given on upcoming results of the 2016/17 measurement.
Bio-inspired neuromuscular reflex based hopping controller for a segmented robotic leg
Authors: Zhao Guoping , Szymanski Florian , Seyfarth Andre
Published: January 2020

It has been shown that human-like hopping can be achieved by muscle reflex control in neuromechanical simulations. However, it is unclear if this concept is applicable and feasible for controlling a real robot. This paper presents a low-cost two-segmented robotic leg design and demonstrates the feasibility and the benefits of the bio-inspired neuromuscular reflex based control for hopping. Simulation models were developed to describe the dynamics of the real robot. Different neuromuscular reflex pathways were investigated with the simulation models. We found that stable hopping can be achieved with both positive muscle force and length feedback, and the hopping height can be controlled by modulating the muscle force feedback gains with the return maps. The force feedback neuromuscular reflex based controller is robust against body mass and ground impedance changes. Finally, we implemented the controller on the real robot to prove the feasibility of the proposed neuromuscular reflex based control idea. This paper demonstrates the neuromuscular reflex based control approach is feasible to implement and capable of achieving stable and robust hopping in a real robot. It provides a promising direction of controlling the legged robot to achieve robust dynamic motion in the future.
Wide-field time-gated SPAD imager for phasor-based FLIM applications
Authors: Ulku Arin , Ardelean Andrei , Antolovic Michel , Weiss Shimon , Charbon Edoardo , Bruschini Claudio , Michalet Xavier
Published: January 2020

We describe the performance of a new wide area time-gated single-photon avalanche diode (SPAD) array for phasor-FLIM, exploring the effect of gate length, gate number and signal intensity on the measured lifetime accuracy and precision. We conclude that the detector functions essentially as an ideal shot noise limited sensor and is capable of video rate FLIM measurement. The phasor approach used in this work appears ideally suited to handle the large amount of data generated by this type of very large sensor (512 × 512 pixels), even in the case of small number of gates and limited photon budget.
Synergistic construction of thermally conductive network in polybenzoxazine with boron nitride hybrid fillers
Authors: Yi Wang , Wu Wei , Drummer Dietmar , Shen Wanting , Chao Liu , Ning Wang
Published: January 2020

Synergistic effect between micrometer boron nitride/nanometer boron nitride (mBN/nBN) at different mass ratio was investigated. Hybrid fillers of mBN/nBN at certain ratio (mBN:nBN = 1:1) performed best synergistic improvement of thermal conductivities of mBN/nBN/polybenzoxazine (mBN/nBN/PBz) composites fabricated via ball-milling followed by a hot-compression method. The effect of hybrid mBN/nBN fillers on thermally conductive coefficient (λ), curing behavior and thermal stability was also studied. The λ value was improved from 0.2276 W · m−1 · K−1 for pristine PBz to 0.9196 W · m−1 · K−1 for (m/n)BN/PBz composites with 25 wt% hybrid filler. Agari model fitting revealed that mBN/nBN hybrid fillers constructed thermally conductive networks much easier than mBN did. The curing behavior and thermal stability of (m/n)BN/PBz composites were dampened with the addition of m/n hybrid fillers. Also, the addition amount of (m/n)BN hybrid filler had great influence on filler alignment in the matrix.
RETRACTED: Comparative study of hot corrosion behavior of thermal sprayed alumina and titanium oxide reinforced alumina coatings on boiler steel
Authors: Singh Gurdeep , Kumar Santosh , Kumar Rakesh
Published: January 2020

The current work evaluates the effect of hot corrosion on ASTM-SA213-T-22 Steel with a coating of 100Al2O3 and 20TiO2-Al2O3 at 900 °C in the molten salt environment of (Na2SO4-60% V2O5). The coatings were sprayed by plasma spray technique. The bare and coated samples were placed inside the muffle furnace at 900 °C for 50 cycles. Each cycle consisted of heating for 1 h and 20 min of cooling at ambient temperature. The kinetics of hot corrosion was analyzed by measuring mass gain after each cycle. The results were achieved by using visual examination, mass change measurement, XRD and SEM/EDS analysis. The result revealed that bare steel was more affected with corrosion and gained more mass due to the development of iron oxide (Fe2O3) than the coated sample. Fe2O3 and Cr2O3 were found as major phase in oxide scale of T-22 uncoated steel specimen. The 100Al2O3 and 20TiO2-Al2O3 coated specimen indicated the reduction in mass gain by 25.41% and 67.02% respectively as compared to uncoated specimen. Al2O3 coating with the combination of TiO2 showed better adhesion properties. The presence of TiO2 enhanced the durability and strength of Al2O3 coating to withstand high temperatures.
Facile synthesis of ultrafine and high purity spherical strontium carbonate via gas-liquid reaction
Authors: Zou Xingwu , Wang Yanan , Liang Shudong , Duan Dongping
Published: January 2020

In this work, a simple gas-liquid precipitation reaction was developed to fabricate spherical strontium carbonate (SrCO3) particles using strontium hydroxide (Sr(OH)2), carbon dioxide (CO2) and ethylene diaminetetraacetic acid strontium salt (EDTA-Sr) as raw materials. The effects of the concentration of EDTA-Sr and Sr(OH)2, airflow rate of CO2 and reaction temperature on the morphology of SrCO3 were investigated. The results showed that spherical SrCO3 particles can be formed when the concentration of EDTA-Sr reached 0.02 M as well as that of Sr(OH)2 was less than 0.1 M. The airflow rate of CO2 gas had little effect on the spherical morphology, and SrCO3 microsphere with good dispersion could be obtained when the reaction temperature reached 50 °C. Under the optimal conditions ([EDTA-Sr] = 0.02 M, [Sr(OH)2] = 0.1 M, 50 °C, [CO2] = 1 l min−1), high purity spherical SrCO3 particles with diameter of 200–800 nm can be easily obtained. Finally, the growth mechanism of spherical SrCO3 has been preliminarily presented, which indicated that EDTA-Sr is an excellent structure-directing agent for forming pherical SrCO3 particles. Our work offers an effective method for large-scale production of high purity spherical SrCO3.
Effect of rolling deformation on microstructure and mechanical properties of Mg-6Sn-3Al-1Zn alloy
Authors: Wei Fuan , Zhang Zhengang , Shi Bo , Yang Chen , Wang Jinhui
Published: January 2020

The Mg-6Sn-3Al-1Zn alloys treated with the solid solution were induced 25%, 45%, 65% and 85% rolling deformation at 400 °C, respectively. The microstructures of as-rolled magnesium alloys were analyzed by XRD, OM, SEM and TEM, the mechanical properties were also measured. The results revealed that the rolled Mg-6Sn-3Al-1Zn alloys were composed of α-Mg matrix phase and Mg2Sn second phase, Mg2Sn distributed at the grain boundaries and intra-grains. With the increasing of the rolling deformation, the volume fraction of Mg2Sn phase distributed at the grain boundaries firstly decreased and then stabilized, the average size of Mg2Sn phase firstly increased and then decreased, the Mg2Sn phase distributed inside the grains gradually transformed from a rod shape to a spherical shape, the volume fraction of the recrystallized grains gradually increased and the average size of the recrystallized grains early decreased and eventually almost unchanged. When the rolling deformation exceeded 25%, the value of tensile strength and Vickers hardness of the Mg-6Sn-3Al-1Zn alloys increased with the rolling deformation. However, when the rolling deformation exceeded 65%, the elongation of the magnesium alloys diminished, however, the strength of as-rolled magnesium alloys did not increase significantly when the amount of rolling deformation increased from 65% to 85%. The mechanical properties were the best when the amount of rolling deformation reached 65%. Meanwhile, the volume fraction and area of Mg2Sn phase distributed on the grain boundaries were 2.9%, 105.5 μm2, the volume fraction and average grain size of recrystallized grains were 87% and 2.2 μm, respectively. In addition, it was worth noting that the Mg2Sn phase distributed inside the grains was radically converted into a spherical shape, and the tensile strength, elongation, hardness of the alloy were 317 MPa, 13% and 77.52 HV, respectively.
Investigation of temperature-induced wear transition of an Mg-10Gd-1.4Y-0.4Zr alloy under non-lubricated sliding conditions
Authors: Wang Yuanbo , Sun Yuan , Liu Zhihui , An Jian
Published: January 2020

The friction and wear behavior of an Mg-10Gd-1.4Y-0.4Zr alloy were investigated in detail within a temperature range of 20 °C–200 °C in order to clarify temperature-induced mild-severe (M-S) wear transition mechanism and verify if contact surface dynamic recrystallization (DRX) temperature criterion can be applicable to elevated temperature M-S wear transition. Coefficient of friction (COF) and wear rate (WR) were plotted against applied load at each test temperature, from which M-S wear transition loads were identified. A wear mechanism transition map was created on test temperature-applied load coordinate system, in which the mild wear region i.e. a safe working region in engineering application was indicated. The M-S wear transition mechanism was proved to be DRX softening by microstructural examination and hardness measurement in subsurfaces. The effects of precipitation and static recrystallization (SRX) occurred at temperatures of 150 °C–200 °C on M-S wear transition were also assessed. According to surface DRX temperature criterion, the transition loads were calculated at temperatures of 20 °C–200 °C, and the results identified applicability of the criterion to wear tests at elevated temperatures.
Liver lesion localisation and classification with convolutional neural networks: a comparison between conventional and spectral computed tomography
Authors: Shapira Nadav , Fokuhl Julia , Schultheiß Manuel , Beck Stefanie , Kopp Felix K , Pfeiffer Daniela , Dangelmaier Julia , Pahn Gregor , Sauter Andreas P , Renger Bernhard , Fingerle Alexander A , Rummeny Ernst J , Albarqouni Shadi , Navab Nassir , Noël Peter B
Published: January 2020

Purpose: To evaluate the benefit of the additional available information present in spectral CT datasets, as compared to conventional CT datasets, when utilizing convolutional neural networks for fully automatic localisation and classification of liver lesions in CT images. Materials and Methods: Conventional and spectral CT images (iodine maps, virtual monochromatic images (VMI)) were obtained from a spectral dual-layer CT system. Patient diagnosis were known from the clinical reports and classified into healthy, cyst and hypodense metastasis. In order to compare the value of spectral versus conventional datasets when being passed as input to machine learning algorithms, we implemented a weakly-supervised convolutional neural network (CNN) that learns liver lesion localisation without pixel-level ground truth annotations. Regions-of-interest are selected automatically based on the localisation results and are used to train a second CNN for liver lesion classification (healthy, cyst, hypodense metastasis). The accuracy of lesion localisation was evaluated using the Euclidian distances between the ground truth centres of mass and the predicted centres of mass. Lesion classification was evaluated by precision, recall, accuracy and F1-Score. Results: Lesion localisation showed the best results for spectral information with distances of 8.22 ± 10.72 mm, 8.78 ± 15.21 mm and 8.29 ± 12.97 mm for iodine maps, 40 keV and 70 keV VMIs, respectively. With conventional data distances of 10.58 ± 17.65 mm were measured. For lesion classification, the 40 keV VMIs achieved the highest overall accuracy of 0.899 compared to 0.854 for conventional data. Conclusion: An enhanced localisation and classification is reported for spectral CT data, which demonstrates that combining machine-learning technology with spectral CT information may in the future improve the clinical workflow as well as the diagnostic accuracy.
A Comprehensive Study of Complexity and Performance of Automatic Detection of Atrial Fibrillation: Classification of Long ECG Recordings Based on the PhysioNet Computing in Cardiology Challenge 2017
Authors: Kleyko Denis , Osipov Evgeny , Wiklund Urban
Published: January 2020

Objective: The 2017 PhysioNet/CinC Challenge focused on automatic classification of atrial fibrillation (AF) in short ECGs. This study aimed to evaluate the use of the data and results from the challenge for detection of AF in longer ECGs, taken from three other PhysioNet datasets. Approach: The used data-driven models were based on features extracted from ECG recordings, calculated according to three solutions from the challenge. A Random Forest classifier was trained with the data from the challenge. The performance was evaluated on all non-overlapping 30 s segments in all recordings from three MIT-BIH datasets. Fifty-six models were trained using different feature sets, both before and after applying three feature reduction techniques. Main Results: Based on rhythm annotations, the AF proportion was 0.00 in the MIT-BIH Normal Sinus Rhythm (N = 46083 segments), 0.10 in the MIT-BIH Arrhythmia (N = 2880), and 0.41 in the MIT-BIH Atrial Fibrillation (N = 28104) dataset. For the best performing model, the corresponding detected proportions of AF were 0.00, 0.11 and 0.36 using all features, and 0.01, 0.10 and 0.38 when using the 15 best performing features. Significance: The results obtained on the MIT-BIH datasets indicate that the training data and solutions from the 2017 Physionet/Cinc Challenge can be useful tools for developing robust AF detectors also in longer ECG recordings, even when using a low number of carefully selected features. The use of feature selection allows significantly reducing the number of features while preserving the classification performance, which can be important when building low-complexity AF classifiers on ECG devices with constrained computational and energy resources.
Generating electromagnetic dark and antidark partially coherent sources
Authors: Hyde Milo W
Published: January 2020

We present two methods to generate an electromagnetic dark and antidark partially coherent source. The first generalizes a recently published scalar approach by representing the stochastic electric field vector components as sums of randomly weighted, randomly tilted plane waves. The second method expands the field’s vector components in series of randomly weighted dark and antidark coherent modes. The statistical moments of the random weights—plane waves in the former method, coherent modes in the latter—are found by comparing the resulting means and covariances to those of the desired electromagnetic dark and antidark source. We validate both methods by simulating the generation of an electromagnetic dark or antidark source and comparing the simulated results to the corresponding theoretical predictions. We find that both methods converge to the theoretical, ensemble-averaged (long-time-averaged) statistics within roughly 500 random field instances. The methods presented in this paper will find use in applications that utilize dark and antidark beams, e.g. atomic optics and optical trapping.
Scattering for the 𝐿² supercritical point NLS
Authors: Adami Riccardo , Fukuizumi Reika , Holmer Justin
Published: January 2020

We consider the 1D nonlinear Schrödinger equation with focusing point nonlinearity. “Point” means that the pure-power nonlinearity has an inhomogeneous potential and the potential is the delta function supported at the origin. This equation is used to model a Kerr-type medium with a narrow strip in the optic fibre. There are several mathematical studies on this equation and the local/global existence of a solution, blow-up occurrence, and blow-up profile have been investigated. In this paper we focus on the asymptotic behavior of the global solution, i.e., we show that the global solution scatters as

t
→
±
∞

t\to \pm \infty

in the

L
2

L^2

supercritical case. The main argument we use is due to Kenig-Merle, but it is required to make use of an appropriate function space (not Strichartz space) according to the smoothing properties of the associated integral equation.
Pharmacists ascribing value of technician certification using an organizational behavior framework
Authors: Desselle Shane P , Mckeirnan Kimberly C , Hohmeier Kenneth C
Published: January 2020

Purpose

To gather rich details about the value of technician certification from diverse groups of pharmacists of various practice settings and levels of experience.

Methods

Focus groups of pharmacists were conducted using a semistructured interview guide in 4 states (California, Idaho, Tennessee, and Washington) varying in pharmacy technician scope of practice, regulation, and education and/or training environment. Participant pharmacists came from health-system, clinic, and community pharmacy environments. The focus groups took the unique approach of an organizational behavior perspective to contextualize technician readiness for practice change and employer fit. The sessions were audio-recorded and transcribed verbatim. Rapid-based qualitative analysis was used to code the data, with summary templates completed by 2 of the researchers for each of the 4 sessions.

Results

There were a total of 33 focus group participants, including 13 male and 20 female pharmacists ranging in age from 27 to 68 years. The 4 major themes yielded by the data were (1) impact of certification, (2) context of certification, (3) organizational culture considerations, and (4) future credentialing. Certification was deemed to have a greater impact on technician maturation, professional socialization, and career commitment than on actual job skills, even while job knowledge was also deemed to be enhanced. In fact, the certification process was also deemed beneficial in that it meshes with on-the-job training. Participants indicated preferences for technician certification examinations to incorporate more content in “soft skills” and also for development of more specialty and/or differentiated certification products.

Conclusion

Pharmacists from 4 states saw value in certification but agreed that certification is but one component of readying technicians for future practice. Suggestions for furthering the value of certification were shared.
Tempel: time-series mutation prediction of influenza A viruses via attention-based recurrent neural networks
Authors: Yin Rui , Luusua Emil , Dabrowski Jan , Zhang Yu , Kwoh Chee Keong
Published: January 2020

Motivation

Influenza viruses are persistently threatening public health, causing annual epidemics and sporadic pandemics. The evolution of influenza viruses remains to be the main obstacle in the effectiveness of antiviral treatments due to rapid mutations. The goal of this work is to predict whether mutations are likely to occur in the next flu season using historical glycoprotein hemagglutinin sequence data. One of the major challenges is to model the temporality and dimensionality of sequential influenza strains and to interpret the prediction results.

Results

In this article, we propose an efficient and robust time-series mutation prediction model (Tempel) for the mutation prediction of influenza A viruses. We first construct the sequential training samples with splittings and embeddings. By employing recurrent neural networks with attention mechanisms, Tempel is capable of considering the historical residue information. Attention mechanisms are being increasingly used to improve the performance of mutation prediction by selectively focusing on the parts of the residues. A framework is established based on Tempel that enables us to predict the mutations at any specific residue site. Experimental results on three influenza datasets show that Tempel can significantly enhance the predictive performance compared with widely used approaches and provide novel insights into the dynamics of viral mutation and evolution.

Availability and implementation

The datasets, source code and supplementary documents are available at: https://drive.google.com/drive/folders/15WULR5__6k47iRotRPl3H7ghi3RpeNXH.

Supplementary information

Supplementary data are available at Bioinformatics online.
AptCompare: optimizedde novomotif discovery of RNA aptamers via HTS-SELEX
Authors: Shieh Kevin R , Kratschmer Christina , Maier Keith E , Greally John M , Levy Matthew , Golden Aaron
Published: January 2020

High-throughput sequencing can enhance the analysis of aptamer libraries generated by the Systematic Evolution of Ligands by EXponential enrichment. Robust analysis of the resulting sequenced rounds is best implemented by determining a ranked consensus of reads following the processing by multiple aptamer detection algorithms. While several such approaches have been developed to this end, their installation and implementation is problematic. We developed AptCompare, a cross-platform program that combines six of the most widely used analytical approaches for the identification of RNA aptamer motifs and uses a simple weighted ranking to order the candidate aptamers, all driven within the same GUI-enabled environment. We demonstrate AptCompare’s performance by identifying the top-ranked candidate aptamers from a previously published selection experiment in our laboratory, with follow-up bench assays demonstrating good correspondence between the sequences’ rankings and their binding affinities.

Availability and implementation

The source code and pre-built virtual machine images are freely available at https://bitbucket.org/shiehk/aptcompare.

Supplementary information

Supplementary data are available at Bioinformatics online.
The role of endometrial stem cells in the pathogenesis of endometriosis and their application to its early diagnosis†
Authors: Liu Yanli , Zhang Zhiqin , Yang Fen , Wang Hongmei , Liang Shengying , Wang Huiling , Yang Jun , Lin Juntang
Published: January 2020

Pelvic pain, infertility, and a high postoperative recurrence rate are associated with endometriosis and adversely affect the physical and mental health of patients. Moreover, these factors place a heavy burden on families and society. The identification of endometrial stem cells (EnSCs) in the eutopic endometrium, menstrual blood, and ectopic lesions of women with endometriosis not only provides new research objects in the context of endometriosis but also promotes and improves our understanding of its pathogenesis. Furthermore, based on previous studies, we reasonably suppose that dysfunctions of eutopic EnSCs play a critical role in the onset of endometriosis and directly cause abnormalities in the endometrium; subsequently, retrograde menstruation facilitates the delivery of abnormal endometrial tissues to the ovaries and pelvic cavity, where they ectopically implant, grow, and form ectopic lesions. Additionally, as a chronically progressive disease, there is a delay (3–11 years) from the first onset of symptoms to the diagnosis of endometriosis. Therefore, the development of a method for early diagnosis with high sensitivity and specificity is essential for endometriosis patients and has the potential to enable early treatment, prevent endometriosis progression, and relieve pain in patients. Thus, focusing on EnSCs will contribute to clarifying the potential pathogenesis of endometriosis and provide support for the application of EnSCs as therapeutic and early diagnostic targets in endometriosis treatment.

Summary sentence

Focusing on endometrial stem cells (EnSCs) will contribute to clarifying the potential pathogenesis of endometriosis and provide support for the application of EnSCs as therapeutic and early diagnostic targets in endometriosis treatment.
In Their Own Words: Susan Stafford
Authors: Verdier James M
Published: January 2020

In Their Own Words chronicles the stories of scientists who have made great contributions to their fields, particularly within the biological sciences. These short oral histories provide our readers a way to learn from and share their experiences. Each month, we will publish in the pages of BioScience and in our podcast, BioScience Talks (http://bioscienceaibs.libsyn.com), the results of these conversations. This fourth oral history is with Dr. Susan Stafford, professor and dean emerita at the University of Minnesota. She previously served as president of the American Institute of Biological Sciences. Note: Both the text and audio versions have been edited for clarity and length.
Chemical Abnormalities in Blood Serum Associated with the Carrier State of Viral Hepatitis
Authors: Reinhold John G
Published: January 2020

The results of studies made for the purpose of identifying carriers of viral hapatitis among blood donors have been reviewed. Some carriers of the virus appear to suffer from a subclinical liver disease recognizable by abnormalities in hapatic tests. The carriers of the virus also tend to have elevated serum cholinesterase activities and elevated serum lipid concentrations.

The use of hepatic tests for screening large numbers of blood donors has been discussed in the light of observations made of the behavior of hepatic tests in proved and suspect carriers. Evidence is presented that among the donors with abnormal hepatic tests there are some that show changes in serum protein as measured by zone electrophoresis, characteristic of liver disease.
Effects of Diet on Blood Lipids In Man
Authors: Keys Ancel , Anderson Joseph T , Fidanza Flaminio , Keys Margaret Haney , Swahn Bengt
Published: January 2020

1. Lipids exist in the blood serum as emulsions ("chylomicrons") and as solutions of lipoprotein containing proteins, cholesterol, and other lipids. Interest in relation to atherosclerosis is centered on the cholesterol and the beta lipoproteins which contain most of the cholesterol.

2. The diet influences the blood lipids in man and animals but great quantitative differences between species makes it essential to study man himself to discover the effects of the diet on the blood lipids in man.

3. The amount of lipid in the chylomicron form in the serum is practically independent of the concentration of cholesterol and lipoproteins in the serum. The correlation between the concentrations of alpha and beta lipoproteins is very low.

4. Experiments on man show that dietary cholesterol per Se, even in large amount, has no important influence on the serum cholesterol concentration but that the latter is markedly affected by the total fat content of the diet.

5. Calorie intake per se has little influence on the blood lipids. Such effect as it has may be secondary to fat metabolism differences commonly associated with differences in calorie intakes.

6. Studies on population samples of healthy men show a marked direct relationship between the content or proportion of fat in the diet on the one hand and the concentration of total cholesterol and of beta lipoproteins in the serum on the other. The effect of the diet tends to be greater in middle-aged men than in younger men.

7. The average concentration of cholesterol in the serum of men in areas where the diets are very high in fats (of the order of 40 per cent of calories), is 25 to 50 per cent greater than the average in areas where the diets are low in fats (of the order of 20 per cent, or less, of calories).

8. A significant effect of dietary fat level on the serum cholesterol concentration is evident in man in a few weeks on a changed diet. The effect tends to increase very slowly with time thereafter and it is most pronounced when comparison is made between populations habitually subsisting on different diets.

9. It is not known how the dietary fat intake exerts its controlling influence on the blood lipids of man but the mechanisms must be complex.
Iron Content of Tissues in Exogenous and Endogenous Hemochromatosis
Authors: Klein Bernard , Gordon Benjamin S , Graef Irving
Published: January 2020

1. Tissues from patients with the endogenous and exogenous (trans-fusion) forms of hemochromatosis were analyzed for iron content and their values compared.

2. Tissues from patients with long-standing anemia were analyzed for iron content.

3. The values obtained in all cases overlap and tissue-iron analysis cannot be used to differentiate the two forms of hemochromatosis.
Rapid Estimation of Amylase Activity of Serum by Turbidimetry
Authors: Peralta Oscar , Reinhold John G
Published: January 2020

The method of Waldron for turbidimetric measurement of amylase activity of duodenal contents has been adapted to measurement of amylase activity of serum. The speed and simplicity of the method make it suitable particularly when results are needed quickly.

Comparison of the results obtained by the turbidimetric method with those of a saccharogenic method showed that high amylase activities could be established dependably by the turbidimetric method.