bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Analysis of the Biochemical Changes in Rats with Polycystic Ovary Syndrome (PCOS) Using Urinary 1H NMR-Based Metabonomics
Authors: Huang Wei , Li Shanxia , Luo Naxin , Lu Kena , Ban Sheng , Lin Hanmei
Published: January 2020

Polycystic ovarian syndrome (PCOS) is the most common endocrine disease that causes reproductive abnormalities in fertile women. It is closely related to the persistent anovulatory, insulin resistance, and high androgen. However, the molecular mechanisms underlying the pathological development of PCOS are still unclear. In this study, we aimed to explore the distinctive metabolic patterns in insulin combined with human chorionic gonadotrophin induced PCOS. The dynamic changes of endogenous metabolites in the development of PCOS were studied using untargeted metabolomic approaches based on nuclear magnetic resonance. The results showed that the degree of PCOS disorder metabolites at different periods was not exactly the same. Twelve significantly differential endogenous metabolites from different time points were selected as potential biomarkers relate to pathological process of PCOS. Among them, six metabolites showed a good diagnostic accuracy with PCOS model. The arginine and proline metabolic pathway was considered as one of the most crucial pathways that affects occurrence and development of PCOS. In addition, IRS-1, Akt, PI3K, IκB, and NF-κB (p65) were significantly changed in the ovary tissue of PCOS rats, which revealed that the IRS-1-PI3K/Akt and NF-κB signal pathway may be involved in the development of PCOS. This study demonstrated that metabolomic analysis is a powerful tool for providing novel insight into understanding the pathogenesis of PCOS and provide a basic reference for the diagnosis of PCOS at the onset stage.
Ein schwieriger Fall von Atemnot
Authors: Gehrer Franziska , Dambach Micha
Published: January 2020

Die vorliegende Falldokumentation beschreibt den Umgang mit Atemnot in der präklinischen Notfallmedizin. Das Symptom „Atemnot“ ist präklinisch häufig und tritt im Zusammenhang mit diversen unterschiedlichen Krankheitsbildern auf. Dies stellt das Rettungsdienstteam aufgrund von limitierten diagnostischen und therapeutischen Mitteln vor Herausforderungen. Anhand des folgenden Falls wird ein mögliches Vorgehen bei Atemnot mit respiratorischer Dekompensation beschrieben. Eine Möglichkeit, präklinisch eine drohende Intubation zu vermeiden oder hinauszuzögern, ist der Einsatz einer nicht invasiven Beatmung (Noninvasive Ventilation, NIV). In der S3-Leitlinie von 2015 wird die Bedeutung eines möglichst frühen Beginns einer NIV-Therapie dargelegt.
Medizinische Psychologie und Medizinische Soziologie im Wandel – Bestandsaufnahme und Perspektiven der beiden Fächer in Deutschland
Authors: Härter Martin , Ditzen Beate , Dragano Nico , Fabry Götz , Kaiser Jochen , Kropp Peter , Richter Matthias , Schut Christina , Knesebeck Olaf von dem , Bremer Daniel
Published: January 2020

Ziel der Studie Durch den Masterplan Medizinstudium 2020 und die Entwicklung des Nationalen Kompetenzbasierten Lernzielkatalogs Medizin (NKLM) wurden bedeutsame Veränderungen in der universitären Medizin angestoßen. Ziel der Studie war eine systematische Erfassung des Standes und der Perspektiven der Fächer Medizinische Psychologie und Soziologie an den medizinischen Fakultäten in Deutschland.

Methodik Es wurde eine online-Befragung zu 5 Themenbereichen (Struktur, Lehre, Forschung, Versorgung, Perspektiven) durchgeführt, die sich an die insgesamt 46 Abteilungen und Institute für Medizinische Psychologie bzw. Soziologie richtete.

Ergebnisse 40 der angeschriebenen 46 Einrichtungen haben den online-Fragebogen aufgerufen, 35 vollständig beantwortet (Rücklauf: 76,1%). 77% der Einrichtungen sind eigenständig. Im Median beschäftigten die Einrichtungen 15 Mitarbeiter (Range: 1–149). 9 Universitäten haben einen Modellstudiengang etabliert. Mehr als die Hälfte der Einrichtungen setzen Simulationspatienten ein und bilden diese aus. Als vorrangige Forschungsschwerpunkte werden die klinische Forschung, die Versorgungsforschung, die Neurowissenschaften sowie klassische medizinpsychologische oder -soziologische Forschungsthemen benannt. Die Einrichtungen erhalten primär öffentliche Fördergelder und veröffentlichen jährlich im Schnitt 19 Publikationen (80% international, Median). Die Publikationsmöglichkeiten werden von 54% der Einrichtungen als „zufriedenstellend“ (2003: 44%) und 29% als „sehr zufriedenstellend“ (2003: 21%) bewertetet. 9 von 27 medizinpsychologischen Instituten geben eine klinische Versorgungsverpflichtung für Patienten und Angehörige mit psychischen oder chronischen körperlichen Erkrankungen an. Knapp die Hälfte der Einrichtungen erwartet durch den Masterplan 2020 eine weitere Profilierung der Fächer.

Diskussion Es hat seit 2003 einen relevanten Zuwachs beim wissenschaftlichen Personal, den eingeworbenen Drittmitteln und Publikationen gegeben. Die Standorte zeigen eine sehr stark ausgeprägte Heterogenität bzgl. der Größe und Ausstattung, was zu Ungerechtigkeiten im Hinblick auf Lehre und Forschung sowie klinische Angebote führt.

Schlussfolgerung Die Fächer Medizinische Psychologie und Medizinische Soziologie haben sich sehr heterogen bzgl. Eigenständigkeit, Größe, Ausstattung und Möglichkeiten an den verschiedenen Standorten in Deutschland weiterentwickelt. Daher ist es in der Zukunft sehr wichtig, dass die beiden Fächer den Dialog untereinander und auch zu anderen psychosozialen Fächern intensivieren, um die derzeitige Entwicklung bezüglich NKLM und Masterplan Medizinstudium 2020 konstruktiv zu beeinflussen. Dies erfordert einerseits einen Ausbau bei benachteiligten Standorten und eine Konsolidierung der bestehenden selbständigen Einrichtungen.
Erfassung des familienmedizinischen Interventionsbedarfs durch eine direkte Befragung von Patienten mit einer psychischen Störung
Authors: Zogas Katharina , Juckel Georg , Mavrogiorgou Paraskevi
Published: January 2020

Hintergrund Die Belastung von Familien psychisch Kranker, besonders von deren Kindern, wird in der Literatur wenig beleuchtet. Gerade die Versorgungssituation Minderjähriger während eines stationären Aufenthalts eines Elternteils und die damit verbundenen Sorgen der Eltern sind wenig erforscht.

Anliegen Erfassung der Versorgungssituation von Kindern und des familiären Interventionsbedarfs stationär behandelter Eltern mit psychischer Erkrankung.

Methodik Im Rahmen einer prospektiven Studie wurden 100 Patienten mit den Hauptdiagnosen affektive Störung, psychische und Verhaltensstörung durch psychotrope Substanzen und Persönlichkeitsstörung mittels eines standardisierten Interviews und Fragebogens näher untersucht.

Ergebnisse In der Mehrheit der Fälle haben die behandelnden Psychiater kein Wissen über die Versorgungssituation der Kinder ihrer Patienten. Der Großteil der Patienten gibt Sorgen um die Versorgung der Kinder während ihres stationären Aufenthalts an und wünscht sich eine Verbesserung der Hilfsmaßnahmen seitens der Klinik.

Schlussfolgerung Die Arzt-Patienten-Interaktion und Kommunikation sollte optimiert werden, damit Interventionsbedarfe gezielt erfasst und individuelle Hilfsmaßnahmen angeleitet werden können.
Führt eine Zunahme depressiver Symptome zu einer Zunahme funktioneller Einschränkungen oder vice versa? Ergebnisse der AgeCoDe/AgeQualiDe-Studie
Authors: Hajek André , Brettschneider Christian , Lühmann Dagmar , van den Bussche Hendrik , Oey Anke , Wiese Birgitt , Weyerer Siegfried , Werle Jochen , Fuchs Angela , Pentzek Michael , Gühne Uta , Riedel-Heller Steffi G. , Weeg Dagmar , Bickel Horst , Heser Kathrin , Wagner Michael , Maier Wolfgang , Scherer Martin , Röhr Susanne , König Hans-Helmut
Published: January 2020

Ziel der Studie Analyse der Beziehung zwischen depressiven Symptomen und funktionellen Beeinträchtigungen bei Hochaltrigen (85+) im Längsschnitt.

Methodik Drei Wellen der multizentrischen prospektiven Kohortenstudie AgeQualiDe wurden genutzt (n = 1272 Beobachtungen). Die Geriatrische Depressionsskala wurde zur Erfassung depressiver Symptome verwendet. Die Instrumental Activities of Daily Living von Lawton und Brody wurde zur Messung funktioneller Beeinträchtigungen eingesetzt.

Ergebnisse Anfängliche Steigerungen in depressiven Symptomen gehen mit späteren Steigerungen funktioneller Beeinträchtigungen einher. Hingegen hängen anfängliche Steigerungen funktioneller Beeinträchtigungen nicht mit späteren Steigerungen in depressiven Symptomen zusammen.

Schlussfolgerung Unsere Ergebnisse deuten darauf hin, dass anfängliche Steigerungen depressiver Symptome mit einer Zunahme funktioneller Beeinträchtigungen bei Hochaltrigen zusammenhängen.
Identifying characteristic time scales in power grid frequency fluctuations with DFA
Authors: Meyer Philipp G. , Anvari Mehrnaz , Kantz Holger
Published: January 2020

Frequency measurements indicate the state of a power grid. In fact, deviations from the nominal frequency determine whether the grid is stable or in a critical situation. We aim to understand the fluctuations of the frequency on multiple time scales with a recently proposed method based on detrended fluctuation analysis. It enables us to infer characteristic time scales and generate stochastic models. We capture and quantify known features of the fluctuations like periodicity due to the trading market, response to variations by control systems, and stability of the long time average. We discuss similarities and differences between the British grid and the continental European grid.
Electric field emission and anomalies of electrical conductivity above room temperature in heterogeneous NiO-SnO2 nano-ceramic composites
Authors: Karmakar S. , Parey Vanshree , Mistari Chetan D. , Thapa Ranjit , More M. A. , Behera D.
Published: January 2020

Microstructural NiO–SnO2 nano-ceramic matrix was synthesized via a solgel auto-combustion technique with a perspective to investigate its noteworthy electric field emission and temperature-induced conduction anomaly. Exceptional field emission performance of nickel-tin oxide composites was discovered with a low turn-on field of 3.9 V/μm and a threshold field of 5.30 V/μm with a good field emission current density of 110.44 μA/cm2 and current stability. Density functional theory was employed to estimate its local work function (Φ) 3.365 eV, and the field enhancement factor (β) was obtained as 1570 by Fowler–Nordheim plot. The anomalies in conductivity spectra at 523 K were detected by a number of physical properties measurement including impedance, conductivity, dielectric, and differential scanning calorimetry with thermal expansion. These phenomena can be rationalized in terms strain-dependent thermal hysteresis effects and localized/delocalized eg electron with a transition from inferior conductive linkage [Ni2+–O2−–Ni2+] and [Sn2+/Sn4+–O2−–Sn2+/Sn4+] to higher conductive linkage [Ni2+–Ni3+] and [Sn2+–Sn4+] of coupled NiO–SnO2 matrix. The temperature dependence frequency exponent (n), ln τ, Rg, Rgb, Cg, and Cgb support additionally the conduction anomaly behavior, and the variation of dielectric constant (ɛr) and loss (tan δ) with temperature around 523 K has been explained in terms of the reduction of space charge layers due to reversal movement of delocalized eg electrons from the grain boundary limit. The frequency dispersing impedance, conductivity, and dielectric spectra with elevated temperature were also demonstrated to comprehend its conduction mechanism with theoretical correlation.
Quantitative thermal measurement by the use of scanning thermal microscope and resistive thermal probes
Authors: Bodzenta Jerzy , Kaźmierczak-Bałata Anna , Harris Kurt
Published: January 2020

Scanning thermal microscopy (SThM) is the only method for thermal measurements providing spatial resolution in the nanometer range. The method combines the topographical imaging of atomic force microscopy (AFM) with the thermal characterization of samples by the use of specially designed AFM probes having a temperature sensor near the apex. Measurements can be carried out in two modes: the temperature contrast (or passive) mode and the conductance contrast (or active) mode. In the first mode, the probe is not heated and the temperature distribution on the sample surface is measured. In the second mode, there are no heat sources in the sample and the probe is heated. The probe temperature depends on the thermal conductance for the heat exchange between the probe and the sample. This thermal conductance depends on the sample thermal conductivity and probe-sample interfacial thermal resistance. If the latter is constant, the distribution of the thermal conductivity on the sample surface can be obtained. The principle of qualitative SThM is quite simple. However, quantitative measurements require rigorous analysis of temperature distribution and heat fluxes in the probe-sample system. This paper provides basic information about SThM starting from first principles, through instrumentation, characterization of probes used for measurements, general theory of the temperature, and the thermal conductivity measurements, to a few examples of practical applications of this method. Finally, perspectives and challenges for SThM based measurements are discussed.
Conductor-backed dielectric metasurface thermal emitters for mid-infrared spectroscopy
Authors: Ali Muhammad O. , Tait R. Niall , Gupta Shulabh
Published: January 2020

A conductor-backed dielectric metasurface thermal emitter at mid-IR frequencies with narrowband emissivity is experimentally demonstrated. The metasurface emitter consists of a high permittivity silicon resonator on top of a ground plane, whose resonant mechanism is explained using image theory. The resonator, placed close to a copper ground plane, is designed to produce a magnetic resonance, resulting in a low-profile device with a single emission peak in its subwavelength frequency range. The thermal emitter is next fabricated using common CMOS processes. Frequency dependent optical constants of plasma-enhanced chemical vapor deposited films of Si, SiO2, and evaporated Cu are also reported in the mid-IR range. Narrowband thermal emission is successfully obtained at around 7.22μm (41.5 THz), which corresponds to the absorption band of SO2. The Q-factor of about 37 is achieved with a peak emissivity of 0.65, which is significantly higher compared to the reported Q-factors of state-of-the-art plasmonic resonators.
A droplet-based microfluidic viscometer for the measurement of blood coagulation
Authors: Mena Sarah E. , Li Yunzi , McCormick Joseph , McCracken Brendan , Colmenero Carmen , Ward Kevin , Burns Mark A.
Published: January 2020

A continuous microfluidic viscometer is used to measure blood coagulation. The viscometer operates by flowing oil and blood into a cross section where droplets are generated. At a set pressure, the length of the droplets is inversely proportional to the viscosity of the blood sample being delivered. Because blood viscosity increases during coagulation as the blood changes from a liquid to a solid gel, the device allows to monitor coagulation by simply measuring the drop length. Experiments with swine blood were carried out in its native state and with the addition of coagulation activators and inhibitors. The microfluidic viscometer detected an earlier initiation of the coagulation process with the activator and a later initiation with the inhibitor compared to their corresponding controls. The results from the viscometer were also compared with the clinical method of thromboelastography (TEG), which was performed concurrently for the same samples. The time to initiation of coagulation in the microfluidic viscometer was correlated with the reaction time in TEG. Additionally, the total time for the measurement of clot strengthening in TEG correlated with the time for the maximum viscosity observed in the microfluidic viscometer. The microfluidic viscometer measured changes in viscosity due to coagulation faster than TEG detected the clot formation. The present viscometer is a simple technology that can be used to further study the entire coagulation process.
Broadband terahertz radiation from metal targets irradiated by a short pulse laser
Authors: Petrov G. M. , Davidson A. , Rock B. , Gordon D. , Hafizi B. , Ting A. , Peñano J.
Published: January 2020

The generation of low-frequency radiation from sub-picosecond laser pulses incident on metal targets is investigated. The laser field drives time-varying currents in a thin sub-surface layer of the metal, which emits broadband radiation that peaks at terahertz frequencies. We present a one-dimensional electrostatic model for copper appropriate for the interaction of laser pulses at normal incidence combined with a radiation model for an infinitely thin disk. The latter uses as input a single parameter, the temporal dependence of the integrated current density on axis, which is derived from the electrostatic model. The salient characteristics of the emitted radiation, such as power, energy, and spectra, are calculated for laser pulses with various intensities and pulse durations. The radiated energy per unit solid angle peaks at a small angle off the target normal and tapers off at larger angles. Analytical scaling of radiated energy with incident laser energy, in the low frequency limit, is obtained in the form εrad∼εlaser3/2. For accurate results, it is imperative to use the full expression for the heat capacity of electrons, in both the degenerate and ideal gas limits. Failure to do so may result in inaccuracies for the computed radiated energy, as large as one order of magnitude. A comparison of calculated and measured radiation energy in the 8–12 GHz frequency range indicates a similar trend with laser energy and comparable magnitude (∼1 fJ).
Thermoelectric properties of Al substituted tetrahedrite
Authors: Tippireddy Sahil , Ghosh Sanyukta , Biswas Rajan , Dasgupta Titas , Rogl Gerda , Rogl Peter , Bauer Ernst , Mallik Ramesh Chandra
Published: January 2020

In this study, aluminum, a p-block element, is substituted at the Cu(1) site, and its effect on the structural and thermoelectric properties of tetrahedrite Cu12−xAlxSb4S13 (x = 0.1, 0.25, 0.5, and 0.75) was investigated. The samples were prepared via solid-state synthesis followed by induction hot pressing. The theoretical calculations, using density functional theory (DFT), showed that the Al substitution results in lowering the band degeneracy near the Fermi level (EF) with EF moving towards the bandgap, indicating effective compensation of holes. The projected density of states (PDOS) revealed almost negligible hybridization of Al states with Cu 3d and S 3p states near EF, thus resulting in relatively low DOS near EF. The electrical resistivity and Seebeck coefficient increased with increasing Al content due to the compensation of holes and reduction of the charge carrier concentration. However, the Seebeck coefficient values were relatively low due to a low DOS near EF, as indicated by the DFT calculations. Although the electronic thermal conductivity (κe) decreased with increasing Al concentration, the magnitudes of the total thermal conductivity (κT) could not be reduced significantly. As a result, a maximum zT of 0.6 at 673 K was obtained for Cu11.9Al0.1Sb4S13. Based on the current study and previously reported results, the paper demonstrates how the phase stability and transport properties of the tetrahedrite are affected significantly by the nature of the substituent at the Cu(1) tetrahedral site.
Uni-traveling-carrier photodiodes
Authors: Ishibashi Tadao , Ito Hiroshi
Published: January 2020

The uni-traveling-carrier photodiode (UTC-PD) is a kind of pin junction photodiode that selectively uses electrons as active carriers. The diode structure has a relatively thin p-type absorber where electrons are generated as minority carriers, and then they diffuse and/or field-accelerate toward the collector. Since the electrons travel in the depleted collector at a ballistically high velocity, the photoresponse performance of a UTC-PD is superior to that of a conventional pin-PD. In this tutorial, the basics of the current response in a UTC-PD, the electron transport in the p-type absorber, and the performance of a terahertz-wave UTC photomixer, as a representative, are described.
Growth of Pr2Ir2O7 thin films using solid phase epitaxy
Authors: Ohtsuki Takumi , Tian Zhaoming , Halim Mario , Nakatsuji Satoru , Lippmaa Mikk
Published: January 2020

(111)-oriented pyrochlore Pr2Ir2O7 epitaxial thin films were successfully fabricated on yttria-stabilized zirconia (111) substrates by means of solid phase epitaxy, namely, the combination of pulsed laser deposition (PLD) of an amorphous precursor film at room temperature, followed by epitaxial crystallization in an ex situ post-annealing process in air. The Pr2Ir2O7 phase cannot be obtained in a conventional in situ PLD process because of severe Ir loss. The Pr2Ir2O7 thin films showed metallic electronic conductivity and the spontaneous Hall effect. These transport properties are similar to the ones reported for bulk single crystal samples, indicating that the thin films had high crystalline quality.
Chemotropism among populations of yeast cells with spatiotemporal resolution in a biofabricated microfluidic platform
Authors: Vo Thanh , Shah Sameer B. , Choy John S. , Luo Xiaolong
Published: January 2020

Chemotropism is an essential response of organisms to external chemical gradients that direct the growth of cells toward the gradient source. Chemotropic responses between single cells have been studied using in vitro gradients of synthetically derived signaling molecules and helped to develop a better understanding of chemotropism in multiple organisms. However, dynamic changes including spatial changes to the gradient as well as fluctuations in levels of cell generated signaling molecules can result in the redirection of chemotropic responses, which can be difficult to model with synthetic peptides and single cells. An experimental system that brings together populations of cells to monitor the population-scale chemotropic responses yet retain single cell spatiotemporal resolution would be useful to further inform on models of chemotropism. Here, we describe a microfluidic platform that can measure the chemotropic response between populations of mating yeast A- and α-cells with spatiotemporal programmability and sensitivity by positioning cell populations side by side in calcium alginate hydrogels along semipermeable membranes with micrometer spatial control. The mating phenotypes of the yeast populations were clearly observed over hours. Three distinct responses were observed depending on the distance between the A- and α-cell populations: the cells either continued to divide, arrest, and develop a stereotypical polarized projection termed a “shmoo” toward the cells of opposite mating type or formed shmoos in random directions. The results from our studies of yeast mating suggest that the biofabricated microfluidic platform can be adopted to study population-scale, spatial-sensitive cell–cell signaling behaviors that would be challenging using conventional approaches.
Luminescence behavior of semipolar (101¯1) InGaN/GaN “bow-tie” structures on patterned Si substrates
Authors: Bruckbauer Jochen , Trager-Cowan Carol , Hourahine Ben , Winkelmann Aimo , Vennéguès Philippe , Ipsen Anja , Yu Xiang , Zhao Xunming , Wallace Michael J. , Edwards Paul R. , Naresh-Kumar G. , Hocker Matthias , Bauer Sebastian , Müller Raphael , Bai Jie , Thonke Klaus , Wang Tao , Martin Robert W.
Published: January 2020

In this work, we report on the innovative growth of semipolar “bow-tie”-shaped GaN structures containing InGaN/GaN multiple quantum wells (MQWs) and their structural and luminescence characterization. We investigate the impact of growth on patterned (113) Si substrates, which results in the bow-tie cross section with upper surfaces having the (101¯1) orientation. Room temperature cathodoluminescence (CL) hyperspectral imaging reveals two types of extended defects: black spots appearing in intensity images of the GaN near band edge emission and dark lines running parallel in the direction of the Si stripes in MQW intensity images. Electron channeling contrast imaging (ECCI) identifies the black spots as threading dislocations propagating to the inclined (101¯1) surfaces. Line defects in ECCI, propagating in the [12¯10] direction parallel to the Si stripes, are attributed to misfit dislocations (MDs) introduced by glide in the basal (0001) planes at the interfaces of the MQW structure. Identification of these line defects as MDs within the MQWs is only possible because they are revealed as dark lines in the MQW CL intensity images, but not in the GaN intensity images. Low temperature CL spectra exhibit additional emission lines at energies below the GaN bound exciton emission line. These emission lines only appear at the edge or the center of the structures where two (0001) growth fronts meet and coalesce (join of the bow-tie). They are most likely related to basal-plane or prismatic stacking faults or partial dislocations at the GaN/Si interface and the coalescence region.
A kinetic Monte Carlo-blueprint for oxygen reduction on oxide-supported PtNi nanoalloys
Authors: Schmidt D. , Asara GG. , Baletto F.
Published: January 2020

To elucidate the effect of the architecture of supported bimetallic nanocatalysts, we developed a new lattice kinetic Monte Carlo based on the classifying and counting adsorption sites with respect to their generalized coordination number. We employed this tool to estimate the activity of MgO-supported PtNi nanoalloys for oxygen reduction. We demonstrated that the presence of Ni atoms in contact with the substrate massively enhances their activity with at least a 7-order of magnitude increase in the turnover of water production with respect to the case where only Pt lay at the interface. We further discussed how the nanoalloy shape affects the activity showing that truncated octahedra are 102 more active than cuboctahedra of similar size. We explained our results in terms of their distinct distribution and occurrence of the most active sites for oxygen reduction leading to the stabilization of different chemical species during the reaction dynamics. Our results suggest that engineering multifaceted and long edge PtNi-nanoalloys with a certain chemical ordering at the support interface would improve their catalytic performance for the oxygen reduction reaction.
Effects of temperature on the flow stress of aluminum in shock waves and rarefaction waves
Authors: Kanel G. I. , Savinykh A. S. , Garkushin G. V. , Razorenov S. V.
Published: January 2020

Elastic–plastic waves of shock compression and unloading in annealed AD1 aluminum were recorded at room temperature, 508 °C, and 610 °C. Using measurements of the parameters of the plastic shock waves and quasi-elastic rarefaction waves at the peak shock stresses from about 1.5 to 4.2 GPa, the strain rate dependences on the stress, the temperatures, and the loading histories were obtained in the range of 105–107 s−1. The initial resistance to high-rate deformation was found to increase anomalously with increasing temperature, but even a small deformation in the shock wave and the accompanying multiplication of dislocations changed the sign of the temperature dependence of the flow stress.
Kinetic sheath in presence of multiple positive ions, negative ions, and particle wall emission
Authors: Schiesko L. , Wünderlich D. , Montellano I. M.
Published: January 2020

The region between a Maxwellian plasma source and a floating or current-carrying surface is described by a static, one-dimensional collisionless kinetic sheath model. In the plasma source, electrons, negative ions, and several positive ion species with different temperatures can be included. The surface (wall) can emit electrons and/or negative ions. When the flux of surface-emitted negative ions and/or electrons reaches a critical value, the sheath becomes space-charge saturated, which leads to the formation of a virtual cathode in front of the emitting wall and sets the maximum current density that can be transported from the surface to the plasma. The analytical results are benchmarked against a particle-in-cell code.
Improved social force model considering conflict avoidance
Authors: Li Qiaoru , Liu Ying , Kang Zengxin , Li Kun , Chen Liang
Published: January 2020

The social force model (SFM) can be applied to characterize pedestrian dynamics in normal scenarios. However, its model of interactions among pedestrians deviates from actual scenarios to some extent. Thus, we propose an improved SFM where pedestrians consider avoiding potential conflicts in advance during the walking process. Meanwhile, the response range of potential conflicts is related to the response time and relative velocity vector. Simulation results demonstrate that the conflict avoidance force plays an important role in guiding pedestrian dynamics. Conflict avoidance makes pedestrian trajectories smoother and more realistic. Moreover, for high pedestrian density (without congestion), moderate values of response time may exist, resulting in the minimum evacuation efficiency. We hope to provide some insights into how to better model interactions among pedestrians during normal evacuation.
Investigation of AFM-based machining of ferroelectric thin films at the nanoscale
Authors: Zhang Fengyuan , Edwards David , Deng Xiong , Wang Yadong , Kilpatrick Jason I. , Bassiri-Gharb Nazanin , Kumar Amit , Chen Deyang , Gao Xingsen , Rodriguez Brian J.
Published: January 2020

Atomic force microscopy (AFM) has been utilized for nanomechanical machining of various materials including polymers, metals, and semiconductors. Despite being important candidate materials for a wide range of applications including data storage and actuators, ferroelectric materials have rarely been machined via AFM. AFM-based machining of ferroelectric nanostructures offers advantages over established techniques, such as bottom-up approaches and focused ion beam milling, in select cases where low damage and low-cost modification of already-fabricated thin films are required. Through a systematic investigation of a broad range of AFM parameters, we demonstrate that AFM-based machining provides a low-cost option to rapidly modify local regions of the film, as well as fabricate a range of different nanostructures, including a nanocapacitor array with individually addressable ferroelectric elements.
Defect characterization of unannealed neutron transmutation doped silicon by means of deep temperature microwave detected photo induced current transient spectroscopy
Authors: Engst C. R. , Eisele I. , Kutter C.
Published: January 2020

Unannealed neutron transmutation doped silicon substrates with a target resistivity of approximately 1000Ωcm are characterized for radiation induced defects by means of microwave detected photoinduced current transient spectroscopy (MD-PICTS). This technique is a contactless advancement of conventional PICTS and does not require the fabrication of ohmic contacts. Defect spectroscopy by means of MD-PICTS is conducted in a broad temperature range between 30 K and 293 K, which makes it possible to identify energetically shallow as well as deep traps. In addition, a wavelength dependent analysis is performed to determine whether a defect is located at the surface or in the bulk material. Three traps with an average activation energy of 68meV, 85meV, and 150meV are observed. In addition, an indication for deep defect states with activation energies between 320meV and 480meV is found. According to the wavelength dependent analysis, it is assumed that all observed traps are bulk defects. Finally, a minority carrier lifetime of approximately 0.7 μs is determined, suggesting that the crystal is heavily damaged by neutron radiation.
Influence of uniaxial stress on phonon-assisted relaxation in bismuth-doped silicon
Authors: Zhukavin R. Kh. , Pavlov S. G. , Stavrias N. , Saeedi K. , Kovalevsky K. A. , Phillips P. J. , Tsyplenkov V. V. , Abrosimov N. V. , Riemann H. , Deβmann N. , Hübers H.-W. , Shastin V. N.
Published: January 2020

The relaxation of electrons bound to bismuth donors in silicon and the effect of uniaxial stress have been studied using the time-resolved single color pump-probe technique. In unstressed Si:Bi, an excited 2p0 donor state is resonantly coupled with the donor 1s(A1) ground state via an intervalley f-TO optical phonon. This results in a very short lifetime (a few ps) of the excited state. Even a slight deformation of the silicon crystal leads to modification of particular interstate energies of the donor, which resolves the resonant coupling to intervalley phonons whose energies remain unchanged. We have shown that once the energy gap between the lower stress-split component of the 2p0 state and the ground state becomes less than the energy of the f-TO phonon, the relaxation of electrons from the excited state slows down to about 300 ps. The experimental data are compared with theoretical calculations of the 2p0 state relaxation rate, which are performed assuming that it is dominated by the emission of intervalley phonons.
Instanton formulation of Fermi’s golden rule in the Marcus inverted regime
Authors: Heller Eric R. , Richardson Jeremy O.
Published: January 2020

Fermi’s golden rule defines the transition rate between weakly coupled states and can thus be used to describe a multitude of molecular processes including electron-transfer reactions and light-matter interaction. However, it can only be calculated if the wave functions of all internal states are known, which is typically not the case in molecular systems. Marcus theory provides a closed-form expression for the rate constant, which is a classical limit of the golden rule, and indicates the existence of a normal regime and an inverted regime. Semiclassical instanton theory presents a more accurate approximation to the golden-rule rate including nuclear quantum effects such as tunneling, which has so far been applicable to complex anharmonic systems in the normal regime only. In this paper, we extend the instanton method to the inverted regime and study the properties of the periodic orbit, which describes the tunneling mechanism via two imaginary-time trajectories, one of which now travels in negative imaginary time. It is known that tunneling is particularly prevalent in the inverted regime, even at room temperature, and thus, this method is expected to be useful in studying a wide range of molecular transitions occurring in this regime.
Cumulant expansion for the treatment of light–matter interactions in arbitrary material structures
Authors: Sánchez-Barquilla M. , Silva R. E. F. , Feist J.
Published: January 2020

Strong coupling of quantum emitters with confined electromagnetic modes of nanophotonic structures may be used to change optical, chemical, and transport properties of materials, with significant theoretical effort invested toward a better understanding of this phenomenon. However, a full theoretical description of both matter and light is an extremely challenging task. Typical theoretical approaches simplify the description of the photonic environment by describing it as a single mode or few modes. While this approximation is accurate in some cases, it breaks down strongly in complex environments, such as within plasmonic nanocavities, and the electromagnetic environment must be fully taken into account. This requires the quantum description of a continuum of bosonic modes, a problem that is computationally hard. We here investigate a compromise where the quantum character of light is taken into account at modest computational cost. To do so, we focus on a quantum emitter that interacts with an arbitrary photonic spectral density and employ the cumulant, or cluster, expansion method to the Heisenberg equations of motion up to first, second, and third order. We benchmark the method by comparing it with exact solutions for specific situations and show that it can accurately represent dynamics for many parameter ranges.
2D group 6 transition metal dichalcogenides toward wearable electronics and optoelectronics
Authors: Yao Jiandong , Yang Guowei
Published: January 2020

Wearable electronic and optoelectronic devices accommodable to various mechanical deformations are becoming increasingly ubiquitous in various realms spanning electronic skins, electronic eyes, intelligent wristbands, lenses, smartphones/watches/glass, robotics, foldable screens, autonomous artificial intelligence systems, etc., which, however, are beyond the scope of conventional bulky semiconductors. Fortunately, 2D group 6 transition metal dichalcogenides (TMDCs) emerge as alternatives, having advantages of strong mechanical strength, high conformability, semitransparency, high biocompatibility, large surface-to-volume ratio, and favorable bandgaps. Highlighting an indispensable physical foundation for reliable wearability, this perspective begins with an elaboration on the structural and mechanical attributes of 2D TMDCs. Then, the latest research advancements of wearable electronic and optoelectronic devices built on them, including field-effect transistors, gas/ion/bio/tactile sensors, photodetectors, and proof-of-concept novel applications, such as electronic noses, flexible displays, and the underlying working mechanisms, are compactly surveyed. This leads us to come up with the predominant challenges standing in the way of further development, and strategies addressing them, along with associated physical principles that are comprehensively outlined.
Changing patterns of pasture production in south-eastern Australia from 1960 to 2015
Authors: Perera Ruchika S. , Cullen Brendan R. , Eckard Richard J.
Published: January 2020

The seasonal pattern of pasture production and its variability from year to year are important for pasture-based livestock production systems in south-eastern Australia because they influence key strategic decisions such as stocking rate and timing of the reproductive cycle. In this study, the effects of observed climate variations over the period 1960–2015 on pasture growth patterns were investigated by using a biophysical modelling approach. Pasture growth rates were simulated using DairyMod biophysical software at five sites ranging from high-rainfall, cool temperate at Elliott in Tasmania to medium-rainfall, warm temperate at Wagga Wagga in southern New South Wales. Annual pasture yields showed a small increasing rate of 50 kg DM/ha.year at Elliott and 40 kg DM/ha.year at Ellinbank (P < 0.05), whereas other sites showed no significant trend over time. A cross-site analysis of seasonal average pasture growth rates predicted under four different discrete periods of 14 years each showed that winter growth has increased steadily through time (P = 0.001), and spring pasture growth rate has decreased (P < 0.001) in 2002–15 compared with the earlier periods. Year-to-year pasture yield variability (coefficient of variation) during autumn and spring seasons has also increased (P < 0.05) across sites in the period 2002–15 compared with 1998–2001. At each site, the number of spring days with water stress (growth limiting factor_water <0.7) was ~10 times greater than the number of days with temperature stress (growth limiting factor_temperature <0.7). There was an increase in the number of days with water stress at Wagga Wagga, and increased heat stress at Wagga Wagga and Hamilton (P < 0.05) in the most recent period. These results highlight the importance of incorporating more heat-tolerant and deep-rooting cultivars into pasture-based production system. Although previous studies of climate-change impact have predicted increasing winter growth rates and a contraction of the spring growing season in the future (2030), this study provides clear evidence that these changes are already occurring under the observed climate in south-eastern Australia.
A 300-fold enhancement of imino nucleic acid resonances by hyperpolarized water provides a new window for probing RNA refolding by 1D and 2D NMR
Authors: Novakovic Mihajlo , Olsen Gregory L. , Pintér György , Hymon Daniel , Fürtig Boris , Schwalbe Harald , Frydman Lucio
Published: January 2020

NMR sensitivity-enhancement methods involving hyperpolarized water could be of importance for solution-state biophysical investigations. Hyperpolarized water (HyperW) can enhance the
1
H NMR signals of exchangeable sites by orders of magnitude over their thermal counterparts, while providing insight into chemical exchange and solvent accessibility at a site-resolved level. As HyperW’s enhancements are achieved by exploiting fast solvent exchanges associated with minimal interscan delays, possibilities for the rapid monitoring of chemical reactions and biomolecular (re)folding are opened. HyperW NMR can also accommodate heteronuclear transfers, facilitating the rapid acquisition of 2-dimensional (2D)
15
N-
1
H NMR correlations, and thereby combining an enhanced spectral resolution with speed and sensitivity. This work demonstrates how these qualities can come together for the study of nucleic acids. HyperW injections were used to target the guanine-sensing riboswitch aptamer domain (GSR
apt
) of the
xpt-pbuX
operon in
Bacillus subtilis
. Unlike what had been observed in proteins, where residues benefited of HyperW NMR only if/when sufficiently exposed to water, these enhancements applied to every imino resonance throughout the RNA. The >300-fold enhancements observed in the resulting
1
H NMR spectra allowed us to monitor in real time the changes that GSR
apt
undergoes upon binding hypoxanthine, a high-affinity interaction leading to conformational refolding on a ∼1-s timescale at 36 °C. Structural responses could be identified for several nucleotides by 1-dimensional (1D) imino
1
H NMR as well as by 2D HyperW NMR spectra acquired upon simultaneous injection of hyperpolarized water and hypoxanthine. The folding landscape revealed by this HyperW strategy for GSR
apt
, is briefly discussed.
Bram Stoker’s Dracula and its undead stories of translation
Authors: Crișan Marius-Mircea
Published: January 2020

Studying the translations of Bram Stoker’s Dracula, one of the most successful novels of all
times, may reveal, even nowadays, several surprises. First published by Constable on 26 May 1897, Bram Stoker’s
Dracula has never been out of print, and it has been translated into about 30 languages (Light 2009). This article starts with an analysis of some keywords in Bram Stoker’s
sources on Transylvania and their translations from Romanian into English, and points to some inaccurate translations which
influenced the novelist to locate the action in Transylvania and change the name of the main vampire character. The following
subchapters examine the recent research on the first translations of Dracula, discussing the Hungarian
translation (1898), the Swedish variant (1899) and the Icelandic versions (1900, 1901), and the last section is dedicated to the
translation into Romanian, published in 1990.
Galician and Spanish in Galicia
Authors: Fernández Rei Elisa
Published: January 2020

The current study analyses the intonation of three types of utterances (broad focus statements,
information-seeking yes-no questions and information-seeking wh-questions) in Galician and Spanish, in order to research the
effects on the intonation of the prolonged contact between these two languages in Galicia. The main aims are to detect possible
hybridisation processes in the intonation of these varieties and determine whether the intonation behaviour is different depending
on the language used or on the language profile of the speakers. To that end, this study presents an empirical study which
analyses these three types of utterances in Spanish and Galician, produced by 22 informants with different linguistic profiles.
The results indicate little variability in the intonation based on the initial and habitual languages of the speakers or the
language in which they produce the corpus. However, the existence of some hybrid patterns in wh-questions has been detected. The
theoretical implications of these results will be discussed within the framework of hybridisation.
From a perceptual point of view, is there prosodic continuity between languages in contact?
Authors: Fernández Planas Ana Ma. , Roseano Paolo , Elvira-García Wendy , Carrera Sabaté Josefina , Román Montes de Oca Domingo
Published: January 2020

This paper contains the results of a set of perception tests that aimed at measuring perceived prosodic distances
between different Romance languages (Italian, Friulian, Sardinian, Catalan, and Spanish). Data were collected within the framework
of the AMPER project. The results were obtained by means of discrimination and identification tasks where the judges were 31
native speakers of Catalan form Barcelona and the stimuli were broad focus statements and yes-no questions in the above-mentioned
languages. The perceived distances are then compared with the results of a dialectometric analysis of acoustic data. This
comparison shows that the perceived distances are related to acoustic differences.
Syntactic relations in ancient and medieval grammatical theory
Authors: Luhtala Anneli
Published: January 2020

It was the Stoics among the ancient philosophers who most vividly
developed the philosophy of language as part of their logic. Within their
theory of meaning, they recognized various types of predicates which
required one or more cases or ‘arguments’ to complete their meaning. A
minimal complete statement consisting of a verb and one or two nominals
formed a logical proposition. This minimal statement also became the point
of departure for syntactic analysis when a theory of syntax began to be
integrated in grammars. Indeed, some of the basic elements of Stoic logic
were adopted into the earliest grammatical theory of syntax, the one
composed by the Greek grammarian Apollonius Dyscolus (2nd century AD). His
theory, as transmitted to the Middle Ages by the Latin grammar of Priscian
(c. 500 AD), established itself as the foundation of the Western theory of
syntax. Within this framework, the verb was regarded as an incomplete
expression, which needed one or more nominal cases to perfect its meaning.
It would then appear that the approach was verb-centered, as it was the verb
that drew the nominal parts of speech into a construction. In the Middle
Ages, grammar came under the influence of Aristotelian logic, and the
functional notions of subject and predicate were incorporated into medieval
syntactic theory. As the predicate was defined as saying something about the
subject, it could be maintained that logically the subject is prior to its
predicate. The same view was implied in the medieval idea of a logical or
natural ordering of the parts of speech, whereby the noun occupied the
primary position. Thus, the noun occupied the first place, because the verb
drew some of its features from the noun, such as number and gender. Such
tensions in the inherited theories provided ingredients for lively scholarly
discussions throughout the Middle Ages.
The notion of dependency in Latin grammar in the Renaissance and the 17th century
Authors: Colombat Bernard
Published: January 2020

This article examines the links of dependency that are woven
between words or phrases in Latin syntax according to Latin grammarians
between 1500 and 1650. They establish a distinction between ‘convenience’ or
‘concord’ (agreement) and ‘rectio’ or ‘regime’ (government) depending on
whether an element controls another element or not. In fact, even in the
case of agreement, one element is mostly dependent on the other. We consider
the following topics from the perspective of the concept of dependency: the
definition and division of syntax; the rules of agreement and exceptions to
them; the evolution of the treatment of verbal government; certain
particular constructions in relation to the preposition, such as the
locative and the ablative which are claimed to be absolute cases; the syntax
of the relative pronoun; the syntax of the conjunction.