bluuebunny/crossref_metadata_2025 huggingface dataset:
A dynamic Spatially Averaged Two-Fluid Model for heat transport in moderately dense gas–particle flows
Authors: Rauchenzauner Stefanie , Schneiderbauer Simon
Published: June 2020

In this study, we derive a spatially averaged two-fluid model for heat transport in moderately dense gas–particle flows. In the context of multiphase turbulence modeling, closure models for the unresolved terms in the filtered transport equations in the presence of mesoscale heterogeneous particle clusters are postulated. In analogy to the drift velocity correction for the resolved gas–particle drag force, we propose to approximate the filtered interphase heat transfer by the resolved heat transfer corrected by a drift temperature. This drift temperature represents the gas-phase temperature fluctuations seen by the particles and can be expressed as a correlation between the solid volume fraction variations and the gas-phase temperature fluctuations, i.e., the turbulent internal energy. Therefore, transport equations for the turbulent internal energies of the phases are derived, where a cluster-induced turbulence production term arises in the gas-phase. Except for the interphase exchange terms, we find that closure models based on single phase turbulence modeling can be applied to the unresolved terms in the transport equations for both the filtered and turbulent internal energies. The interphase exchange terms can be expressed by the variances of the temperatures scaled by correlation coefficients. A dynamic adjustment of the correlation coefficients by using test-filters in coarse-grid simulations is proposed. In an a priori study, the developed closure models show good agreement with the predictions obtained by filtering fine-grid, two-fluid model simulation data of Geldart type A and B particles in three-dimensional wall-bounded fluidized beds.
Interface studies of molecular beam epitaxy (MBE) grown ZnSe–GaAs heterovalent structures
Authors: Fan Zongjian , Yaddanapudi Krishna , Bunk Ryan , Mahajan Subhash , Woodall Jerry M.
Published: June 2020

Comprehensive investigations on ZnSe/GaAs and GaAs/ZnSe interfaces were carried out by photoluminescence and transmission electron microscopy as a part of realizing high quality ZnSe–GaAs (100) hetero-valent structures (HS). The nature of the ZnSe/GaAs interface under different surface terminations of GaAs was examined. The ZnSe/Ga-terminated GaAs was found to have a superior optical and microstructural quality, with a chemical interface consisting of a mixture of both GaAs and ZnSe atomic constituents. For GaAs/ZnSe interface studies, a low-temperature migration enhanced epitaxy (LT-MEE) growth technique was used to grow GaAs layers under the conditions compatible to the growth of ZnSe. Both Ga and As-initialized LT-MEE GaAs/ZnSe interfaces were investigated. A defective transition layer was observed along the As-initialized GaAs/ZnSe interface, which may be attributed to the formation of the Zn3As2 compound. The correlation between the observed optical as well as structural properties of both (GaAs/ZnSe and ZnSe/GaAs) interfaces and growth conditions used in this study is discussed in detail. This study could provide a valuable insight into the interface nature of the ZnSe–GaAs HS.
Temporary anions of the dielectric gas C3F7CN and their decay channels
Authors: Ranković M. , Kumar T P Ragesh , Nag P. , Kočišek J. , Fedor J.
Published: June 2020

We probe the transient anion states (resonances) in the dielectric gas C4F7N by the electron energy loss spectroscopy and the dissociative electron attachment spectroscopy. The vibrationally inelastic electron scattering leads to two excitation types. The first is the excitation of specific vibrational modes that are assigned with the help of an infrared spectrum of this molecule and quantum chemistry calculations. In the second type of vibrational excitation, the excess energy is randomized via internal vibrational redistribution in the temporary anion, and the electrons are emitted statistically. The electron attachment proceeds in three different regimes. The first is the formation of the parent C4F7N− anion at energies close to 0 eV. The second is a statistical evaporation of the F-atom, leading to the defluorinated anion C4F6N−. Finally, the third is dissociative electron attachment proceeding via the formation of several resonances and leading to a number of fragments. The present data explain the puzzling recent results of the pulsed-Townsend experiments with this gas.
Positive vs negative resistance response to hydrogenation in palladium and its alloys
Authors: Das S. S. , Kopnov G. , Gerber A.
Published: June 2020

Resistive solid state sensors are widely used in multiple applications, including molecular and gas detection. The absorption or intercalation of the target species varies the lattice parameters and an effective thickness of thin films, which is usually neglected in the analyses of their transport properties in general and the sensor response in particular. Here, we explore the case of palladium-based thin films absorbing hydrogen and demonstrate that the expansion of thickness is an important mechanism determining the magnitude and the very polarity of the resistance response to hydrogenation in high resistivity films. The model of the resistance response that takes into account the modifications of thickness was tested and confirmed in three Pd-based systems with variable resistivity: thin Pd films above and below the percolation threshold, thick Pd–SiO2 granular composite films with different contents of silica, and Pd-rich CoPd alloys where resistivity depends on the Co concentration. The superposition of the bulk resistivity increase due to hydride formation and the decrease in the film resistance due to the thickness expansion provides a consistent explanation of the hydrogenation response in both continuous and discontinuous films with different structures and compositions.
Transferability of neural network potentials for varying stoichiometry: Phonons and thermal conductivity of MnxGey compounds
Authors: Mangold Claudia , Chen Shunda , Barbalinardo Giuseppe , Behler Jörg , Pochet Pascal , Termentzidis Konstantinos , Han Yang , Chaput Laurent , Lacroix David , Donadio Davide
Published: June 2020

Germanium manganese compounds exhibit a variety of stable and metastable phases with different stoichiometries. These materials entail interesting electronic, magnetic, and thermal properties both in their bulk form and as heterostructures. Here, we develop and validate a transferable machine learning potential, based on the high-dimensional neural network formalism, to enable the study of MnxGey materials over a wide range of compositions. We show that a neural network potential fitted on a minimal training set reproduces successfully the structural and vibrational properties and the thermal conductivity of systems with different local chemical environments, and it can be used to predict phononic effects in nanoscale heterostructures.
Mechanism of charge redistribution at the metal–semiconductor and semiconductor–semiconductor interfaces of metal–bilayer MoS2 junctions
Authors: Wang Qian , Shao Yangfan , Shi Xingqiang
Published: June 2020

Layer-number-dependent performance of metal–semiconductor junctions (MSJs) with multilayered two-dimensional (2D) semiconductors has attracted increasing attention for their potential in ultrathin electronics and optoelectronics. However, the mechanism of the interaction and the resulting charge transfer/redistribution at the two kinds of interfaces in MSJ with multilayered 2D semiconductors, namely, the metal–semiconductor (M–S) and the semiconductor–semiconductor (S–S) interfaces, have not been well understood until now, although that is important for the overall Schottky barrier height and the energy-band-offset between different layers of the 2D semiconductors. Here, based on state-of-the-art density functional theory calculations, the mechanisms of bonding and asymmetric electron redistribution at the M–S and S–S interfaces of metal–bilayer MoS2 junctions are revealed. Multiple mechanisms collectively contribute to the electron redistribution at the two kinds of interfaces, and the dominant mechanism depends on both the dimensionality (2D vs 3D) and the work function of metal electrodes. For the M–S interface, the pushback effect and metal-induced gap states play a dominant role for MSJs with 3D metal, while the covalent-like quasi-bonding feature appears for MSJs with medium-work-function 2D metals, and charge transfer plays a main role for MSJs with 2D metals that have very large or small work functions. For the S–S interface, it inherits the electron-redistribution behavior of the M–S interface for MSJs with 2D metal, while opposite electron-redistribution appears in MSJs with 3D metal. These mechanisms provide general insights and new concepts to better understand and use MSJs with multilayered 2D semiconductors.
Water-mediated biomolecular dynamics and allostery
Authors: Leitner David M. , Hyeon Changbong , Reid Korey M.
Published: June 2020

Dynamic coupling with water contributes to regulating the functional dynamics of a biomolecule. We discuss protein–water dynamics, with emphasis on water that is partially confined, and the role of protein-confined water dynamics in allosteric regulation. These properties are illustrated with two systems, a homodimeric hemoglobin from Scapharca inaequivalvis (HbI) and an A2A adenosine receptor (A2AAR). For HbI, water–protein interactions, long known to contribute to the thermodynamics of cooperativity, are seen to influence the dynamics of the protein not only around the protein–water interface but also into the core of each globule, where dynamic and entropic changes upon ligand binding are coupled to protein–water contact dynamics. Similarly, hydration waters trapped deep inside the core region of A2AAR enable the formation of an allosteric network made of water-mediated inter-residue contacts. Extending from the ligand binding pocket to the G-protein binding site, this allosteric network plays key roles in regulating the activity of the receptor.
Momentum-exchange current drive by electrostatic waves in an unmagnetized collisionless plasma
Authors: Ochs Ian E. , Fisch Nathaniel J.
Published: June 2020

For a planar electrostatic wave interacting with a single species in a collisionless plasma, momentum conservation implies current conservation. However, when multiple species interact with the wave, they can exchange momentum, leading to current drive. A simple, general formula for this driven current is derived. As examples, we show how currents can be driven for Langmuir waves in electron–positron–ion plasmas, and for ion-acoustic waves in electron–ion plasmas.
Bond dissociation energies of the diatomic late transition metal sulfides: RuS, OsS, CoS, RhS, IrS, and PtS
Authors: Sorensen Jason J. , Tieu Erick , Morse Michael D.
Published: June 2020

The spectra of RuS, OsS, CoS, RhS, IrS, and PtS have been recorded near their respective bond dissociation energies using resonant two-photon ionization spectroscopy. The spectra display an abrupt drop to baseline when the bond dissociation energy (BDE) is exceeded. It is argued that spin–orbit and nonadiabatic interactions among the myriad of states that result from the ground and low-lying separated atom limits cause the molecules to predissociate rapidly as soon as the ground separated atom limit is exceeded in energy. Thus, the observed sharp predissociation thresholds are assigned as the 0 K BDEs of the molecules. With this assumption, the BDEs are assigned as follows: 4.071(8) eV (RuS), 4.277(3) eV (OsS), 3.467(5) eV (CoS), 3.611(3) eV (RhS), 4.110(3) eV (IrS), and 4.144(8) eV (PtS). Using thermochemical cycles, the gas-phase enthalpies of formation at 0 K, ΔfH0 K°, were calculated to be 531.8(4.3) kJ mol−1 (RuS), 651.2(6.3) kJ mol−1 (OsS), 365.3(2.2) kJ mol−1 (CoS), 481.5(2.1) kJ mol−1 (RhS), 546.7(6.3) kJ mol−1 (IrS), and 438.9(1.5) kJ mol−1 (PtS). The ionization energies of RuS, CoS, and RhS were also calculated using data on the BDEs of the associated cations and were found to be 8.39(10) eV (RuS), 8.40(9) eV (CoS), and 8.46(12) eV (RhS). Combining these data with predissociation measurements of other transition metal sulfide BDEs, the periodic trends in the transition metal sulfide BDEs are discussed and the BDEs of the transition metal sulfides are compared to those of the corresponding selenides. The BDEs of the sulfides are found to be 15.4% greater than those of the corresponding sulfides.
Ultraviolet photodissociation dynamics of the n-butyl, s-butyl, and t-butyl radicals
Authors: Sun Ge , Zheng Xianfeng , Song Yu , Lucas Michael , Zhang Jingsong
Published: June 2020

Photodissociation dynamics of the jet-cooled n-butyl radical via the 3s Rydberg state and the s-butyl radical via the 3p Rydberg states in the ultraviolet region of 233 nm–258 nm, as well as the t-butyl radical via the 3d Rydberg states at 226 nm–244 nm, are studied using the high-n Rydberg atom time-of-flight technique. The H-atom photofragment yield spectra of the n-butyl, s-butyl, and t-butyl radicals show a broad feature centered around 247 nm, 244 nm, and 234 nm, respectively. The translational energy distributions of the H + C4H8 products, P(ET)’s, of the three radicals are bimodal, with a slow (low ET) component peaking at ∼6 kcal/mol and a fast (high ET) component peaking at ∼52 kcal/mol–57 kcal/mol, ∼43 kcal/mol, and ∼37 kcal/mol for n-butyl, s-butyl, and t-butyl, respectively. The fraction of the products’ translational energy in the available energy, ⟨ fT⟩, is 0.31, 0.30, and 0.27 for n-butyl, s-butyl, and t-butyl, respectively. The H-atom product angular distributions of the slow component are isotropic for all three radicals, while those of the fast component are anisotropic for n-butyl and s-butyl with an anisotropy parameter β ∼ 0.7 and ∼ 0.3 and that of the fast component of t-butyl is nearly isotropic. The bimodal product translational energy and angular distributions indicate two dissociation pathways to the H + C4H8 products in these three radicals, a direct, prompt dissociation on the repulsive potential energy surface coupling with the Rydberg excited states, and a unimolecular dissociation of the hot radical on the ground electronic state after internal conversion from the Rydberg states.
Occurrence of emerging contaminants and analysis of oestrogenic activity in the water and sediments from two coastal lagoons in south-eastern Brazil
Authors: Cunha Danieli L. , Muylaert Samuel , Nascimento Marilia T. L. , Felix Louise C. , Gomes Giselle , Bila Daniele M. , Fonseca Estefan M.
Published: June 2020

There is increasing concern in the scientific community regarding emerging contaminants in aquatic matrices because of the potential effects of these contaminants on aquatic biota. In recent decades, the Itaipu–Piratininga lagoon system has suffered a series of environmental impacts, among which water pollution stands out. In this context, the aim of this study was to analyse the occurrence of pharmaceuticals and endocrine disrupters in water (dissolved and particulate phases) and in surface sediments, and their potential oestrogenic effects. Contaminant concentrations were determined by gas chromatography–mass spectrometry, whereas oestrogenic activity was evaluated using the yeast oestrogen screen assay. Of the 12 compounds analysed, concentrations of gemfibrozil, acetaminophen and diclofenac were below the limit of detection. The compounds with the highest detection frequency in the water were bisphenol A>4-octylphenol>naproxen>oestradiol, whereas in the sediment were bisphenol A>naproxen>oestradiol. Higher pharmaceutical concentrations and numbers of microcontaminants were observed in August 2017 (winter), which can be explained by the lower dilution and degradation capacity of these compounds during winter. Oestrogenic activity was observed in at least one of the three matrices (i.e. water (dissolved and particulate phases) and surface sediments) at all sampling stations and in both sampling campaigns (January and August 2017). Combined with data in the literature data, the results of this study indicate probable adverse effects of contaminants on aquatic organisms of this lagoon system.
International students' views on sexual health: a qualitative study at an Australian university
Authors: Parker Anneka , Harris Peter , Haire Bridget
Published: June 2020

Background The number of international students at Australian universities is rapidly increasing, and they contribute significantly to Australia’s economy. However, concerns have been raised for the health and wellbeing of international students, and there is limited information concerning international students with regard to their sexual health. Methods: Overall, 13 individual semi-structured in-depth interviews were conducted with 13 international students at an Australian university, aiming to understand the views and experiences of international students with regard to their sexual health and wellbeing. The interviews were analysed thematically, generating four themes. Results: Participants had a varied understanding of sexual consent, which often included concerns about the practicalities of saying ‘no’ to unwanted sexual interactions and misinformation about the effect of reporting sexual misconduct on their privacy and visa status. Cultural and familial taboos were often inherited, but many participants described an evolution of personal views and attitudes regarding topics such as sex before marriage and same-sex relationships, which had occurred since moving to Australia. Participants expressed that they received large amounts of information about sexual health, but often lacked the skills to navigate that information and access relevant support. Conclusions: These data, along with participants’ suggestions for future support and education, are important for understanding the complex experiences of international students at Australian universities, and should be considered when implementing future sexual health education and support programs.
Outreach services to brothels facilitate sexually transmissible infection testing for Asian sex workers in regional Australia
Authors: Mesure Joanna , Ryder Nathan
Published: June 2020

Outreach services providing sexually transmissible infection (STI) testing on-site in brothels were introduced in 2012 by Pacific Clinic Newcastle, Australia. Asian female sex workers (FSW) were more likely than non-culturally and linguistically diverse (CALD) FSW to access testing via outreach services than in clinics (OR 2.38, 95% CI 1.82–3.11, P < 0.0001) and to test positive for chlamydia or gonorrhoea (OR 2.58, 95% CI 1.58–4.20, P = 0.0001). Outreach services offering testing on-site in brothels are recommended to facilitate access for Asian FSW in similar settings.
A new approach for studying vertical infiltration
Authors: Poulovassilis Alexander , Argyrokastritis Ioannis
Published: June 2020

The exact contribution of the pressure head gradient term during the vertical infiltration process, occurring in homogeneous porous media under zero ponding head, is determined analytically to advance the knowledge related to the infiltration phenomenon. This contribution is smaller than that of the horizontal infiltration by a factor at which is a measurable function of the infiltration time t, characteristic of each porous body. By adding to this contribution that of gravity, a new two-term analytical equation is formulated which exactly reproduces an available vertical cumulative curve and satisfies the physics governing infiltration process. The properties of at allow the derivation of an equation accurate for small and moderate t and of another one accurate for all t, including large values. By applying new methodologies, the values of the sorptivity and hydraulic conductivity are determined analytically from an available cumulative infiltration curve. Philip’s two-term equation, which does not satisfy the physical requirements at the upper extreme of t, and three other equations that do satisfy it, are examined in the light of the findings of the present work. The proposed equations are able to describe the vertical infiltration process and may be used to provide the hydraulic properties.
Interatomic coulombic decay rate in endohedral complexes
Authors: Khokhlova Margarita , Bahmanpour Laila , Bachhawat Nikhil , Cooper Bridgette , Averbukh Vitali
Published: June 2020

Interatomic coulombic decay (ICD) in van der Waals endohedral complexes was predicted to be anomalously fast. However, the available theoretical calculations of the ICD rates in endohedral complexes only consider the equilibrium geometry, in which the encapsulated atom is located at the centre of the fullerene cage. Here we show analytically that the dominant contribution of the dipole plasmon resonance to ICD does not deviate from its equilibrium geometry value, while contributions of higher multipole plasmons to the ICD can be neglected for most atomic displacements possible for an endohedral complex at room temperature. This is in contrast to the behaviour predicted for ionic endohedral compounds. Our results show that the conclusion of the earlier works on the ultrafast character of the ICD in endohedral complexes holds generally for a wide range of geometries possible under a thermal distribution, rather than only for the equilibrium geometry.
A flipped U(1)
R
extension of the Standard Model
Authors: Nam Cao H
Published: June 2020

In this work, we study an extension of the standard model (SM) based on the gauge symmetry SU(3)
C
× SU(2)
L
× U(1)
Y′ × U(1)
R
where only the right-handed fermions have nonzero U(1)
R
charge and the weak hypercharge of the SM is identified as a combination of the U(1)
Y′ and U(1)
R
charges. The gauge charge assignment of the fields is constrained by the conditions of the anomaly cancellation and the gauge invariance of the Yukawa couplings. The light neutrino masses are generated via the type-I seesaw mechanism where the Majorana masses of the right-handed neutrinos are related to the U(1)
Y′ × U(1)
R
symmetry breaking scale. Then, we discuss the constraints on the free parameters of the model from various current experiments, such as the precision measurement of the total Z width, ρ parameter, atomic parity violation of cesium, LEP and LHC bounds. In addition, we investigate the potential of probing for the signal of the new neutral gauge boson based on the forward–backward asymmetry for the process e
+
e
− → μ
+
μ
− which is the most sensitive mode at the ILC.
A novel concept for adaptive friction damper based on electrostatic adhesion
Authors: Testoni Oleg , Bergamini Andrea , Bodkhe Sampada , Ermanni Paolo
Published: June 2020

This work presents a novel concept for an adaptive friction damper based on electrostatic adhesion for medium to small industrial applications and investigates the effects of electrostatic tuning on the energy dissipated by the damper under quasi-static as well as dynamic conditions. The novel damper has a low mechanical complexity. The amount of energy dissipated can be controlled through an electric voltage and be easily adapted to different working conditions. The concept is based on a stack of electrostatic clutches hinged around a common axis, which can dissipate energy through Coulomb friction. An electric field is used to vary the maximum shear stress transferred by the clutches and, consequently, to control the damping level. A prototype of the damper was manufactured and tested. The experimental results demonstrate the increase in the resistive moment of the clutches with increasing electric field and display the capability of the concept to adapt the damping level of a single-degree-of-freedom resonating system. The presented concept might replace linear dampers in rotating machines operating at different regimes, in road vehicles as well as in aircrafts.
Effect of Ce on phase formation and magnetic properties of (Nd–Pr)2.28Fe13.58B1.14 melt-spun ribbons
Authors: Rong M H , Ma J , Yao Q R , Wang J , Rao G H , Zhou H Y , Jin Z P
Published: June 2020

The phase formation of the (Nd0.70Pr0.30−xCex)2.28Fe13.58B1.14 (x = 0.10, 0.15, and 0.20; hereafter defined as Pr20Ce10, Pr15Ce15 and Pr10Ce20, respectively) and (Nd0.60Pr0.40−yCey)2.28Fe13.58B1.14 (y = 0.10, 0.20, and 0.30; hereafter defined as Pr30Ce10, Pr20Ce20 and Pr10Ce30, respectively) alloys that were prepared via the arc-melting method was investigated experimentally. The x-ray diffraction results revealed that all alloys annealed at 1173 K for 360 h consisted of a (NdPrCe)2Fe14B main phase with a tetragonal Nd2Fe14B-typed structure (space group P42/mnm) and an α-Fe minor phase, except for the Pr10Ce30 alloy, which contained an additional CeFe2 phase. The magnetic properties of the (Nd0.70Pr0.30−xCex)2.28Fe13.58B1.14 and (Nd0.60Pr0.40−yCey)2.28Fe13.58B1.14 ribbons that were prepared by melt spinning were examined. The remanence (Br) and maximum magnetic energy product ((BH)max) of the (Nd0.70Pr0.30−xCex)2.28Fe13.58B1.14 ribbons increased first and then decreased, whereas the coercivity (Hcj) of the ribbons increased with an increase in Ce content. The Br and (BH)max of the (Nd0.60Pr0.60−yCey)2.28Fe13.58B1.14 ribbons increased, whereas the Hcj of the ribbons decreased gradually with an increase in Ce content. This changed behavior of magnetic properties is attributed to the variation of volume fraction of the α-Fe phase and different phase formations in the melt-spun ribbons. The Curie temperatures (Tc) of all ribbons decreased slightly with Ce substitution, which results from the lower Curie temperatures of Pr2Fe14B and Ce2Fe14B. The Pr10Ce30 ribbon with a higher Ce content exhibited optimal magnetic properties (Br = 9.71 kGs, Hcj = 13.09 kOe, (BH)max = 18.78 MGOe), which indicates that suitable magnetic properties of the Nd–Pr–Ce–Fe–B melt-spun ribbons can be achieved by alloy-composition and phase-formation design.
Theoretical study on photoelectric properties of FAPbI3 doped with Ge
Authors: Gao Li-Ke , Tang Yan-Lin , Diao Xin-Feng
Published: June 2020

FAPbI3(NH2CHNH2PbI3) is an organic-inorganic hybrid perovskite containing Pb, which has good photoelectric characteristics and great potential in the application of low-cost and high energy efficiency photoelectric devices. In order to reduce the pollution of Pb to the environment, the first-principles based on density functional theory(DFT) is used to compare and study the photoelectric parameters such as the band structure, density of states(DOS), absorption coefficient, reflectivity, conductivity and dielectric function of FAPb1−xGexI3(x = 0.0,0.33,0.50,0.67,1.0). The results show that the 4p orbital electrons of Ge and the 6p orbital electrons of Pb and 5p orbital electrons of I are hybridized after doped with Ge, which change the band structure of FAPbI3. The result is that the optical band gap of the material is narrowed, the curvature of the band is increased, the effective mass of electrons and holes is reduced, the absorption peak of visible light increases and the absorption range increases. And the reflectivity and energy loss of the material also increase at the same time. The super SOC effect of the heavy metal Pb element leads to the splitting of the conduction band level of FAPbI3, the conduction band value drops sharply, and the band gap decreases sharply. We found that when the doping ratio of x in FAPb1−xGexI3 was between 0.55 and 0.65, the optimal band gap was between 1.3–1.4 eV. Therefore, reasonable regulation of Ge’s doping ratio can improve the photoelectric conversion efficiency of FAPbI3. This study can provide some theoretical guidance for experimental research and search for new efficient and environmentally friendly perovskite solar materials.
Co/Ni multilayers ordered according to a periodic, Fibonnacci and Thue Morse sequence obtained by Atomic Layer Deposition
Authors: Saavedra E , Burr J P , Alburquenque D , Palma J L , García-Martín J M , Escrig J
Published: June 2020

Co/Ni multilayers ordered according to a periodic, Fibonnacci and Thue Morse sequence have been obtained by Atomic Layer Deposition and a subsequent process of thermal reduction. The morphology of the multilayers was investigated by scanning electron microscopy, while longitudinal hysteresis curves were obtained by magneto-optical magnetometry of Kerr effect. The morphology of the films varies as a function of their sequence and thickness. Multilayers exhibit coercivities much higher than expected from samples synthesized with other methods. The control of the magnetic properties of multilayers, as a function of their sequence, may allow their use in spintronic devices.
Adaptation of and Protocol for the Validation of the Alcohol Use Disorders Identification Test (AUDIT) in the Russian Federation for Use in Primary Healthcare
Authors: Rehm Jürgen , Neufeld Maria , Yurasova Elena , Bunova Anna , Gil Artyom , Gornyi Boris , Breda João , Bryun Evgeniy , Drapkina Oxana , Fadeeva Eugenia , Kalinina Anna , Khaltourina Daria , Klimenko Tatiana , Kontsevaya Anna , Koshkina Evgenia , Martynova Natalya , Nadezhdin Alexey , Soshkina Kristina , Tetenova Elena , Vujnovic Melita , Vyshinsky Konstantin , Ferreira-Borges Carina
Published: June 2020

Aims

To adapt and validate the Alcohol Use Disorders Identification Test (AUDIT) for use in the Russian Federation and countries with Russian-speaking populations by:

Methods

Systematic review of past use and validation of the Russian-language AUDIT. Interviews to be conducted with experts to identify problems encountered in the use of existing Russian-language AUDIT versions. A pilot study using a revised translation of the Russian-language AUDIT that incorporates country-specific drinking patterns in the Russian Federation.

Results and Conclusions

The systematic review identified over 60 different Russian-language AUDIT versions without systematic validation studies. The main difficulties encountered with the use of the AUDIT in the Russian Federation were related to the lack of:

A revised version of the Russian-language AUDIT was created based on the pilot studies, and was validated in primary healthcare facilities in all regions in 2019/2020.
Affective Drinking Motives, Delinquency and Binge Drinking: A Comparison of Male and Female High School Seniors
Authors: Walters Glenn D
Published: June 2020

Aim

The purpose of this study was to determine whether the association between affective drinking motives, delinquency and binge drinking varied as a function of sex and if so, whether delinquency moderated the relationship between affective drinking motives and binge drinking in late adolescent males and females.

Methods

Participants were 623 (257 males, 366 females) high school seniors from the 2018 Monitoring the Future study. A principal components analysis was initially performed to create component scores for the first factor of a 15-item drinking motives scale subsequently labeled affective drinking motives. These scores, along with sex and a measure of delinquency, were then entered into a three-way interaction. The interaction was found to correlate significantly with binge drinking. Because of the significant three-way interaction, analyses were performed on male and female participants separately.

Results

Analyses conducted on male participants revealed a moderate correlation between affective drinking motives and binge drinking but no evidence of an interaction between affective drinking motives and delinquency. Analyses performed on female participants, on the other hand, identified a significant main effect for affective drinking motives and a negative interaction between affective drinking motives and delinquency, indicating that the relationship between affective drinking motives and binge drinking was strongest when delinquency was low.

Conclusions

These results suggest that while delinquency had no apparent impact on the affective drinking motive–binge drinking correlation in boys, low delinquency clearly amplified the counter-binge drinking effects of low affective drinking motives in girls.
Estimates of Occupational Inhalation Exposures to Six Oil-Related Compounds on the Four Rig Vessels Responding to theDeepwater HorizonOil Spill
Authors: Huynh Tran B , Groth Caroline P , Ramachandran Gurumurthy , Banerjee Sudipto , Stenzel Mark , Quick Harrison , Blair Aaron , Engel Lawrence S , Kwok Richard K , Sandler Dale P , Stewart Patricia A
Published: June 2020

Background

The 2010 Deepwater Horizon (DWH) oil spill involved thousands of workers and volunteers to mitigate the oil release and clean-up after the spill. Health concerns for these participants led to the initiation of a prospective epidemiological study (GuLF STUDY) to investigate potential adverse health outcomes associated with the oil spill response and clean-up (OSRC). Characterizing the chemical exposures of the OSRC workers was an essential component of the study. Workers on the four oil rig vessels mitigating the spill and located within a 1852 m (1 nautical mile) radius of the damaged wellhead [the Discoverer Enterprise (Enterprise), the Development Driller II (DDII), the Development Driller III (DDIII), and the HelixQ4000] had some of the greatest potential for chemical exposures.

Objectives

The aim of this paper is to characterize potential personal chemical exposures via the inhalation route for workers on those four rig vessels. Specifically, we presented our methodology and descriptive statistics of exposure estimates for total hydrocarbons (THCs), benzene, toluene, ethylbenzene, xylene, and n-hexane (BTEX-H) for various job groups to develop exposure groups for the GuLF STUDY cohort.

Methods

Using descriptive information associated with the measurements taken on various jobs on these rig vessels and with job titles from study participant responses to the study questionnaire, job groups [unique job/rig/time period (TP) combinations] were developed to describe groups of workers with the same or closely related job titles. A total of 500 job groups were considered for estimation using the available 8139 personal measurements. We used a univariate Bayesian model to analyze the THC measurements and a bivariate Bayesian regression framework to jointly model the measurements of THC and each of the BTEX-H chemicals separately, both models taking into account the many measurements that were below the analytic limit of detection.

Results

Highest THC exposures occurred in TP1a and TP1b, which was before the well was mechanically capped. The posterior medians of the arithmetic mean (AM) ranged from 0.11 ppm (‘Inside/Other’, TP1b, DDII; and ‘Driller’, TP3, DDII) to 14.67 ppm (‘Methanol Operations’, TP1b, Enterprise). There were statistical differences between the THC AMs by broad job groups, rigs, and time periods. The AMs for BTEX-H were generally about two to three orders of magnitude lower than the THC AMs, with benzene and ethylbenzene measurements being highly censored.

Conclusions

Our results add new insights to the limited literature on exposures associated with oil spill responses and support the current epidemiologic investigation of potential adverse health effects of the oil spill.
Sexual dimorphism in floral scents of the neotropical orchid Catasetum arietinum and its possible ecological and evolutionary significance
Authors: Brandt Katharina , Machado Isabel Cristina , Navarro Daniela Maria do Amaral Ferraz , Dötterl Stefan , Ayasse Manfred , Milet-Pinheiro Paulo
Published: June 2020

Dioecy in angiosperms is often associated with sexual dimorphism in floral traits other than the sexual organs. Species of the neotropical orchid genus Catasetum produce unisexual flowers characterized by a remarkable morphological sexual dimorphism. Catasetum species emit strong floral perfumes that act as both signal and reward for male euglossine bee pollinators. Although the role of floral perfumes of Catasetum in attracting euglossine pollinators is well investigated, little is known about whether perfumes differ between floral sexes and, if they do, whether this chemical dimorphism influences the pollination ecology of the plants. Taking Catasetum arietinum as a model species, our aim was to observe the behaviour of pollinators on male and female flowers and to compare scent properties (i.e. chemical composition, total amount and temporal fluctuation) of male and female flowers. Floral scent samples were collected by using dynamic headspace methods and were analysed via gas chromatography coupled with mass spectroscopy (GC-MS). Catasetum arietinum is pollinated by males of two Euglossa species (i.e. E. nanomelanotricha and E. securigera). Bees approached male and female inflorescences of C. arietinum in similar proportions but landed significantly more often and spent more time on female flowers, which emitted more scent than male flowers. Furthermore, the amount of scent emitted varied across the different times of sampling, corresponding to the pattern of the diel foraging activity of pollinating bees on male and female flowers. The chemical composition of scents differed significantly between sexes. The two major compounds (Z)-methyl-p-methoxycinnamate and (E)-geranyl geraniol contributed most to this difference. This is the first case of sexual dimorphism reported in orchid floral perfumes. We discuss the influence of sex-specific floral scents on the behaviour of euglossine pollinators and offer new insights into the ecological and evolutionary significance of divergence in floral scents among dioecious plants.
A-14 Competitiveness and Past Nondisclosure Decreases Future Concussion Reporting Intention Among Males in High-Contact Sports
Authors: Doucette M M , Wong R E , Du Plessis S , Garcia-Barrera M
Published: June 2020

Objective

With some variability, research indicates that a high percentage (20–60%) of athletes do not report post-concussion symptoms, despite having sufficient concussion knowledge. Our study examined whether competitiveness and past reporting predicted future reporting intention in males participating in high contact sports.

Method

Participants included 92 male athletes (M = 19.35 years, SD = 4.35) recruited from a mid-sized Canadian city participating in high contact sports (American football, rugby, or hockey). Competitiveness was measured using the Sport Orientation Questionnaire. The Rosenbaum Concussion Knowledge and Attitudes Survey-Student Version was used to assess concussion knowledge and nondisclosure. Logistic regression was conducted to predict future intention of playing despite experiencing post-concussion symptoms. Age, knowledge, competitiveness, sport, and past history of concussion nondisclosure were included as predictors.

Results

Age, sport, and concussion knowledge were not significant predictors. Competitiveness was a significant predictor for the model, such that higher competitiveness predicted less likelihood to report post-concussion symptoms. Our findings also suggest that athletes who have not disclosed a concussion in the past are more likely to have higher intention to continue to play with symptoms of a concussion in the future. Over half (54%) of the athletes reported past history of concussion nondisclosure.

Conclusions

Interventions focusing on increasing general concussion knowledge are not adequate to prevent symptom nondisclosure. The results suggest that highly competitive athletes or athletes with a past history of nondisclosure are most vulnerable to future nondisclosure. These findings could help improve future interventions by targeting athletes at high-risk of concussion nondisclosure.
A-16 The Clinical Utility of a Novel Dual-Task Assessment for Sport-Related Concussion in Collegiate Athletes
Authors: Erdman N K , Hertel J , Saliba S A , JM MacKnight , Broshek D K , Resch J E
Published: June 2020

Objective

To compare the clinical utility of a novel dual-task assessment for sport-related concussion (SRC) to other commonly-used clinical measures in collegiate athletes.

Method

Participants consisted of 38 collegiate athletes (19 concussed and 19 matched comparisons, 53% male, age = 20.0 ± 1.34 years, height = 178.2 ± 12.12 cm, mass = 83.4 ± 21.89 kg). Participants were administered the dual-task assessment, Balance Error Scoring System (BESS), Standardized Assessment of Concussion (SAC), and tandem gait (TG) test within 48 hours (T1), at 5 days (T2), and when symptom-free (T3) following a diagnosed SRC. The novel dual-task assessment consisted of concurrent administration of the SAC and TG. The ImPACT and Sensory Organization Test (SOT) were administered at T3 in alignment with the university’s concussion management policy. Sensitivity, specificity, and diagnostic accuracy using receiver operator curve analyses were calculated for each measure for T1-T3 using previously established interpretation guidelines.

Results

For sensitivity, a range of values were observed from T1-T3 for the dual-task (88%–37%), BESS (47%–47%), SAC (53%–26%), TG test (53%–11%). Similarly, a range of specificity values were observed for the dual-task (58%–84%), BESS (84%–63%), SAC (79%–84%), and TG test (95%–100%) from T1-T3. At T3, the ImPACT and SOT were observed to have a sensitivity of 32% and 100% and specificity of 16% and 100%, respectively. A range of diagnostic accuracy values were observed from T1-T3 for the dual-task (84%–62%), BESS (59%–50%), SAC (64%–56%), TG test (82%–71%), ImPACT (T3 = 66%), and SOT (T3 = 50%).

Conclusions

The dual-task assessment had comparable or higher diagnostic accuracy as other commonly-used clinical measures of SRC throughout clinical recovery in collegiate athletes.
A-19 Utility OF ImPACT Pediatric In Patients Aged 5–9 Following Concussion
Authors: Feder A H , Kegel N , Eagle S R , Fazio-Sumrok V , Trbovich A , Kontos A P
Published: June 2020

Objective

Computerized neurocognitive testing has demonstrated sensitivity to the effects of concussion (Kontos et al., 2014). While there have been attempts to develop post-injury assessments for youth concussion, most lack compelling empirical support regarding psychometric properties. The purpose of this study was to expand upon preliminary support for the ImPACT Pediatric neurocognitive test battery (Newman et al., 2013) by examining the clinical utility of this measure in the evaluation of concussion in a pediatric population.

Method

Children, aged 5–9 years, presented to an outpatient clinic within 30 days of concussion. Participants completed ImPACT Pediatric at all clinic visits. ImPACT Pediatric is a computerized neurocognitive test battery that assesses various aspects of memory and visual processing speed. Paired t-tests were used to compare ImPACT Pediatric subtest scores at initial visit and clinical clearance.

Results

Participants (n = 63) were predominantly male (57.8%), aged 7.5 ± 1.0 years who presented to the clinic in 8.5 ± 5.9 days from injury and recovered in 34.1 ± 23.5 days. Design Rotation average time (−11.3%; p < 0.001), Stop and Go average correct time (−4.3%; p = 0.030), and Picture Touch immediate memory average time (−11.3%; p < 0.001) significantly improved from initial visit to clearance. Memory subtest scores did not significantly improve from initial visit to clearance.

Conclusions

Average time was significantly improved at the time of clinical clearance on the Design Rotation, Stop and Go, and Picture Match subtests. The findings indicate that ImPACT Pediatric timed subtests can detect changes between initial and clearance visits. Pediatric ImPACT can be a useful component of the comprehensive evaluation of concussion in younger children.
A-27 APOE & BDNF Polymorphisms Interact to Affect Memory Performance at Baseline in Adolescent Athletes
Authors: Merritt V C , Guty E , Riegler K , Brewer M , Fink S , Echemendia R J , Arnett P A
Published: June 2020

Objective

Although several single-nucleotide polymorphisms have been associated with cognitive functioning in a variety of healthy and clinical samples, the influence of gene x gene interactions on cognition is poorly understood. The purpose of this study was to examine interactive relationships between apolipoprotein E (APOE) and brain-derived neurotrophic factor (BDNF) polymorphisms on cognitive functioning in a sample of healthy adolescent athletes.

Method

Participants of this cross-sectional study included 82 athletes (53.7% male, age, M = 12.85, SD = 1.13) who completed the Immediate Post-Concussion and Cognitive Testing (ImPACT) computerized battery at baseline as part of a school-based sports-concussion management program. Athletes also provided a buccal sample for determination of their APOE and BDNF genotypes. Two-way analyses of variance (ANOVAs) were used to evaluate the effect of APOE (ε4+ vs. ε4-) and BDNF (Met+ vs. Met-) genotypes on the ImPACT cognitive composites.

Results

ANOVAs showed non-significant main effects for both APOE and BDNF genotypes across the four cognitive composites. However, there was a significant APOE x BDNF genotype interaction for the verbal (p = .01; ηp2 = .08) and visual (p = .013; ηp2 = .08) memory composites, such that ε4+/Met+ carriers demonstrated poorer performance relative to the other allele combinations (ε4+/Met-, ε4−/Met+, ε4−/Met-). No significant interactions were observed for the visual motor speed (p = .20; ηp2 = .02) or reaction time (p = .87; ηp2 < .001) composites.

Conclusions

Our findings suggest a meaningful relationship between APOE and BDNF genotypes on verbal and visual memory performance in healthy adolescent athletes. These findings will need to be replicated using much larger samples, and future studies will need to explore these associations following sports-related concussion.
A-36 Understanding Parental Knowledge of and Attitudes towards Youth Sport-Related Concussion
Authors: Roberts S D , Fraser-Thomas J , Register-Mihalik J , Schatz P , Wojtowicz M
Published: June 2020

Objective

The study objective was to examine parental knowledge of, and attitudes towards, youth sport-related concussion in a Canadian sample.

Method

A community sample of seventy-six families (n = 120 children) completed the study questionnaire comprised of demographic and sport history information, as well as questions about concussion knowledge (factual and perceived) and attitudes (i.e. concussion management and treatment attitudes). All participants had children actively involved in sport. Predominantly mothers completed the questionnaire (74%), and families ranged from one-to-three children (M age = 9 yr 5mth, SD = 2 yr 11mth).

Results

On average, parents achieved 76% accuracy on factual concussion knowledge (M = 21.19, SD = 2.55), with the majority (75%) perceiving their responses as accurate (perceived knowledge). Most parents displayed a favourable attitude toward concussion reporting and management (54/63; 85.7%). Families with low social risk status (SRS) had higher perceived knowledge compared to families with high SRS (t(60) = 2.29, p = .026), but not actual knowledge (p = .87). Mixed linear regression models were used to examine relationships between sociodemographic factors and concussion knowledge and attitudes. Higher SRS (F(1,74) = 9.60, p = .003) was related to lower perceived knowledge.

Conclusions

Families with higher SRS had less confidence in their youth sport-related concussion knowledge despite having accurate knowledge. Understanding sociodemographic factors associated with concussion attitudes and knowledge is an important first step for informing policies and keeping youth active in sports.