bluuebunny/crossref_metadata_2025 huggingface dataset:
Fuzzy logic and Lyapunov‐based non‐linear controllers for HCV infection
Authors: Hamza Ali , Ahmad Iftikhar , Uneeb Muhammad
Published: March 2021

Hepatitis C is the liver disease caused by the Hepatitis C virus (HCV) which can lead to serious health problems such as liver cancer. In this research work, the non‐linear model of HCV having three state variables (uninfected hepatocytes, infected hepatocytes and virions) and two control inputs has been taken into account, and four non‐linear controllers namely non‐linear PID controller, Lyapunov Redesign controller, Synergetic controller and Fuzzy Logic‐Based controller have been proposed to control HCV infection inside the human body. The controllers have been designed for the anti‐viral therapy in order to control the amount of uninfected hepatocytes to the desired safe limit and to track the amount of infected hepatocytes and virions to their reference value which is zero. One control input is the Pegylated interferon (peg‐IFN‐α) which acts in reducing the infected hepatocytes and the other input is ribavirin which blocks the production of virions. By doing so, the uninfected hepatocytes increase and achieve the required safe limit. Lyapunov stability analysis has been used to prove the stability of the whole system. The comparative analysis of the proposed nonlinear controllers using MATLAB/Simulink have been done with each other and with linear PID. These results depict that the infected hepatocytes and virions are reduced to the desired level, enhancing the rate of sustained virologic response (SVR) and reducing the treatment period as compared with previous strategies introduced in the literature.
Update Übelkeit und Erbrechen in der Geriatrie
Authors: Schaefer Rolf
Published: March 2021

Was ist neu?

Definition/Epidemiologie/Ursachen Übelkeit ist, ebenso wie das Erbrechen, ein Symptom und kein eigenständiges Krankheitsbild. Dies macht eine genaue Angabe der Häufigkeit im Alter schwierig. Schätzungsweise jeder 2. bis 3. ist betroffen.

Veränderungen des Magen-Darm-Trakts Übelkeit im Alter hat viele mögliche Ursachen (zerebral gesteuert oder durch gastrointestinale Veränderungen bedingt). Die physiologische Alterung des Magen-Darm-Trakts bewirkt allein keine Übelkeit.

Mögliche Ursachen für Übelkeit und Erbrechen Viele Erkrankungen, die gehäuft im Alter auftreten, können ursächlich für Übelkeit und Erbrechen sein. Dazu gehören z. B. Diabetes mellitus oder Morbus Parkinson. Aber auch die häufig bestehende Multimedikation kann zu gastrointestinalen Symptomen führen.

Diagnostik Basis der Diagnostik sind die detaillierte Anamnese und die gute körperliche Untersuchung. Die weiteren diagnostischen Schritte müssen individuell auf den Patienten abgestimmt sein. Eine offizielle Leitlinie zur Diagnostik gibt es nicht.

Therapie Die Therapie zielt zunächst auf die Behandlung der Ursache (ursächliche Grunderkrankung(en) oder Multimedikation). Erst im zweiten Schritt sollte eine symptomorientierte Medikation erfolgen. Viele mögliche Medikamente sind jedoch beim alten Menschen inadäquat.
Rheuma, Entzündung und kardiovaskuläres Risiko
Authors: Nguyen Phuong , Baerwald Christoph
Published: March 2021

Was ist neu?

Kardiovaskuläres Risikoprofil von Patienten mit entzündlichen Gelenkerkrankungen Patienten mit entzündlichen Gelenkerkrankungen leiden häufiger an kardiovaskulären Erkrankungen als die Normalbevölkerung. Trotz der Feststellung dieses erhöhten Risikos vor mehr als einem Jahrzehnt konnte die kardiovaskuläre Morbidität und Mortalität in dieser Patientengruppe noch nicht gesenkt werden. Auch im Jahr 2021 bleibt das kardiovaskuläre Risikomanagement von Patienten mit entzündlichen Gelenkerkrankungen ein relevanter Aspekt für Hausärzte, klinisch tätige Rheumatologen und Forschende.

Kardiovaskuläre Risikobewertung Gängige Berechnungen des kardiovaskulären Risikos für die Normalbevölkerung schätzen das Risiko für Patienten mit entzündlichen Gelenkerkrankungen oft falsch niedrig ein. Obwohl die Entzündung immer wieder als unabhängiger Risikofaktor bestätigt wird, fehlt es derzeit noch an einem validierten Entzündungsparameter, der in Risikoberechnungen integriert werden kann. Zudem muss der Einfluss weiterer krankheitsspezifischen Faktoren – etwa die Krankheitsaktivität oder die Therapie – auf das kardiovaskuläre Risiko untersucht werden. Aktuell existiert noch keine eigenständige kardiovaskuläre Risikobewertung für Patienten mit entzündlichen Gelenkerkrankungen.

Medikamentöse Beeinflussung des kardiovaskulären Risikos Krankheitsmodifizierende antirheumatische Medikamente reduzieren das kardiovaskuläre Risiko. Dieser Effekt konnte in aktuellen Studien besonders für Biologika bestätigt werden. Tumornekrosefaktor-α-Inhibitoren senken beispielsweise die Rate der kardiovaskulären Ereignisse um 15 %. Auch Methotrexat, das wahrscheinlich am häufigsten eingesetzte Medikament, kann einen positiven Einfluss auf das kardiovaskuläre Risiko haben. Daten zu den relativ neuen Januskinase-Inhibitoren werden in den kommenden Jahren erwartet.
Entwicklung sekundärer Kopfschmerzen durch Exposition oder Übergebrauch einer Substanz
Authors: Lenz Britta , Obermann Mark , Katsarava Zaza
Published: March 2021

Sekundäre Kopfschmerzen, die auf die Exposition, den Übergebrauch oder den Entzug einer Substanz zurückzuführen sind, sind in Kapitel 8 der 3. Auflage der Internationalen Klassifikation von Kopfschmerzerkrankungen (ICHD-3) aufgeführt. Es werden 3 Unterkapitel unterschieden: 8.1. Kopfschmerz zurückzuführen auf Substanzgebrauch oder Substanzexposition, 8.2. Kopfschmerz zurückzuführen auf einen Medikamentenübergebrauch und 8.3. Kopfschmerz zurückzuführen auf den Entzug einer Substanz. Ersterer – Kopfschmerz zurückzuführen auf Substanzgebrauch oder Substanzexposition – bezieht sich auf einen Kopfschmerz mit Beginn unmittelbar oder innerhalb von Stunden nach der Exposition. Hingegen ist der „Kopfschmerz zurückzuführen auf einen Medikamentenübergebrauch“ (MOH) definiert als ein Kopfschmerz, der an 15 oder mehr Tagen pro Monat bei Patienten mit einer vorbestehenden primären Kopfschmerzerkrankung auftritt und sich als Folge der regelmäßigen Einnahme akuter Kopfschmerzmedikamenten über einen Zeitraum von mehr als 3 aufeinanderfolgende Monate entwickelt hat. Bezüglich letzterem, ist der Entzug von Koffein, Östrogen und Opioiden am häufigsten mit der Entwicklung von Kopfschmerzen assoziiert.

Der vorliegende Artikel soll einen Überblick über die neuesten Erkenntnisse zur Klassifikation, Pathophysiologie und zu Behandlungsstrategien dieser sekundären Kopfschmerzentitäten geben und legt den Schwerpunkt dabei auf die Unterkapitel 8.1 und 8.2. der ICHD-3-Klassifikation.
Korrektur einer mandibulären Asymmetrie mit frontal offenem
Biss mittels Frontzahnextraktion und Lingualtechnik
Authors: Pauls Alexander
Published: March 2021

Einleitung Bestimmte Dysgnathien sowie von der Norm abweichende
Zahnformen stellen für Patienten nicht nur funktionelle Risiken,
sondern auch ästhetische Probleme dar. Die vorgestellte Kasuistik
beschreibt die Korrektur beider Problemfelder.

Kasuistik Präsentiert wird der Fall einer 61-jährigen
Patientin mit Laterognathie, moderater Angle-Klasse III, frontalem Kreuz-
und Kopfbiss, frontal offenem Biss und ausgeprägten
Engständen sowie deren Korrektur mittels vollständig
individueller lingualer Apparatur und Extraktion eines unteren Frontzahnes
sowie nachfolgender konservierender Umgestaltung einiger Frontzähne
durch den Hauszahnarzt. Um die Ästhetik im Bereich der
Extraktionslücke zu optimieren, erfolgte die temporäre
Applikation eines Pontics durch den Kieferorthopäden.

Schlussfolgerungen Bei geeigneten Behandlungsfällen kann eine
Frontzahnextraktion im Unterkiefer die Therapie einer Asymmetrie sowie einer
moderate Angle-Klasse III mit frontalem Kopf-/Kreuzbiss
unterstützen. Auch komplexe Fälle lassen sich mit einer
vollständig individuellen lingualen Apparatur erfolgreich und
vorhersagbar behandeln.
Auswirkungen von mit Xylitol imprägnierten Zahnbürsten auf den
parodontalen Status und die mikrobielle Flora bei kieferorthopädischen
Patienten
Authors: Jung Britta
Published: March 2021

Ziel war es zu untersuchen, ob mit Xylitol imprägnierte Zahnbürsten
(Happy Morning Xylitol Hager-Werken, Duisburg, Deutschland) einen Effekt auf die
parodontale Gesundheit und die mikrobielle Keimflora bei kieferorthopädisch
zu behandelnden Patienten mit schlechter Mundhygiene hat.
Value of Nontechnical Skills in Minimally Invasive Surgery
Authors: Araujo Sergio Eduardo Alonso , Kim Nam Jin , Cendoroglo Neto Miguel , Klajner Sidney
Published: March 2021

Nontechnical skills are of increasing importance in surgery and surgical training. The main studies on its impact on the safety and effectiveness of surgical interventions were mainly published in the first decade of the 2000s. Due to the significant technical complexity and great diversity of instruments for nontechnical skills evaluation, the interest in training and in measuring the impact on surgical safety has relatively decreased. However, the advent of minimally invasive surgery and its peculiar technical characteristics of sophisticated technique and constant innovation through the adoption of new materials and drugs has rekindled interest in this expertise area.

In the present review, we have revisited the main instruments available to measure nontechnical skill of surgical teams and analyzed the role of the main competencies on which they are based, such as situational awareness, leadership and communication skills, and the consistency of the intraoperative decision-making process.

We conclude that despite the great consensus that exists among all members of the health team on the importance of nontechnical skills for the surgical team in minimally invasive surgery, the reproducible evidence on the subject is scarce and laborious to obtain. To the extent that protecting and expanding nontechnical skills is fundamental to the path toward the high reliability of health institutions, it is possible to anticipate here the role of these institutions as promoters of continuity and new research models in this area of knowledge, especially in minimally invasive surgery, an access route to which more and more patients undergoing surgical treatment in these same institutions are submitted.
Safe Introduction of New Technologies and Techniques in Minimally Invasive Colorectal Surgery
Authors: Melani Armando Geraldo Franchini , Romagnolo Luis Gustavo Capochin , Davila Eduardo Parra
Published: March 2021

In the past 20 years, colorectal surgery has experienced important advances as a result of new technologies that have increasingly transformed conventional open surgery into maximal usage of minimally invasive approaches. While many tools are being developed to change the way that operations are being performed, quality must not suffer. We describe here some of the aspects to pursue to achieve optimal and safe outcomes while utilizing minimally invasive techniques such as robotic surgery, transanal total mesorectal excision, as well as the role of immunofluorescence.
Elements that affect foreign tourists’ satisfaction: a case study in Seoul, Korea
Authors: Ryu Chehyun , Kwon Youngsang
Published: March 2021

City tourism is one of the fastest growing industries worldwide. City tourism based on the attractiveness of the city is an important policy objective to secure competitiveness and sustainability of the city. However, as a city attracts more tourists, this uniqueness tends to decrease with the introduction of global corporate franchises as well as the construction of standardised buildings. Policymakers focus more on building hotels and shopping centres than on enhancing the cityscape. Therefore, this article aims to analyse the effect of cityscapes on tourist satisfaction. It encourages policymakers to bear in mind what really matters in fostering tourist satisfaction. During this research, about 250 foreign tourists visiting Seoul were given questionnaires to complete. Ordered logistic regression was used to analyse the data collected. The results demonstrated that among several elements that affected tourist satisfaction, such as shopping, security, and public transportation services, the cityscape had the greatest influence. This fact shows that urban competitiveness and sustainable city tourism are more important than the construction of new buildings or infrastructure in the short term. In the future, policymakers should seek to strengthen the city’s competitiveness from a longer-term perspective for its sustainable economic revitalisation.
Measures of both perceived general and specific risks and benefits differentially predict adolescent and young adult tobacco and marijuana use: findings from a Prospective Cohort Study
Authors: McKelvey Karma , Gaiha Shivani Mathur , Delucchi Kevin L. , Halpern-Felsher Bonnie
Published: March 2021

Health behavior theorists and prevention researchers use a variety of measures of adolescent and young adult (AYA) risk and benefit perceptions to predict tobacco-use and marijuana-use behaviors. However, studies have not examined whether and how perception measures that ask about likelihood of more general outcomes such as “harm” versus ask about specific risk or benefit outcomes compare or whether they differentially predict AYA willingness to use if one of your best friends were to offer it and intentions to use in the next year; and if these measures have differential ability to predict actual use of tobacco and marijuana. We used data from a prospective cohort of California AYAs to create and test new scales to measure perceptions of specific health and social outcomes related to risks (e.g., smell bad) and benefits (e.g., look cool) related to tobacco and marijuana, and then addressed three questions: (1) Whether and how measures of perceptions of specific social and health risks and benefits (for our purposes “specific measures”) and measures of perceived general harm are differentially associated with measures of willingness, social norms, and intentions to use? (2) Are specific versus general measures differentially associated with and predictive of tobacco and cannabis use behavior? (3) Are specific perceptions measures differentially predictive of behavior compared to measures of willingness, social norms, and behavioral intentions? Our results demonstrate that to better predict AYA tobacco and marijuana use, measures that address general outcomes, such as harmfulness, as well as willingness and behavioral intention should be used. We also found that measures of specific perceived risks (short-term, long-term, social) and benefits were unrelated and correlated differently with different products. For example, adolescents perceived both risks and benefits from using products like e-cigarettes, and perceived greater risk from smokeless tobacco compared to combustible cigarettes. These findings indicate that measures of specific perceived social and health outcomes can be useful to discern nuanced differences in motivation for using different substances. Study implications are important for survey dimension-reduction and assessing relationships among perceptions, motivations, and use of tobacco and marijuana products.
Quasicharacters, recoupling calculus, and Hamiltonian lattice quantum gauge theory
Authors: Jarvis P. D. , Rudolph G. , Schmidt M.
Published: March 2021

We study the algebra R of G-invariant representative functions over the N-fold Cartesian product of copies of a compact Lie group G modulo the action of conjugation by the diagonal subgroup. Using the representation theory of G on the Hilbert space H=L2(GN)G, we construct a subset of G-invariant representative functions, which, by standard theorems, span H and thus generate R. The elements of this basis will be referred to as quasicharacters. For N = 1, they coincide with the ordinary irreducible group characters of G. The form of the quasicharacters depends on the choice of a certain unitary G-representation isomorphism, or reduction scheme, for every isomorphism class of irreps of G. We determine the multiplication law of R in terms of the quasicharacters with structure constants. Next, we use the one-to-one correspondence between complete bracketing schemes for the reduction of multiple tensor products of G-representations and rooted binary trees. This provides a link to the recoupling theory for G-representations. Using these tools, we prove that the structure constants of the algebra R are given by a certain type of recoupling coefficients of G-representations. For these recouplings, we derive a reduction law in terms of a product over primitive elements of 9j symbol type. The latter may be further expressed in terms of sums over products of Clebsch–Gordan coefficients of G. For G = SU(2), everything boils down to combinatorics of angular momentum theory. In the final part, we show that the above calculus enables us to calculate the matrix elements of bi-invariant operators occurring in quantum lattice gauge theory. In particular, both the quantum Hamiltonian and the orbit type relations may be dealt with in this way, thus reducing both the construction of the costratification and the study of the spectral problem to numerical problems in linear algebra. We spell out the spectral problem for G = SU(2), and we present sample calculations of matrix elements of orbit type relations for the gauge groups SU(2) and SU(3). The methods developed in this paper may be useful in the study of virtually any quantum model with polynomial constraints related to some symmetry.
The effects of free-stream turbulence on the performance of a model wind turbine
Authors: Gambuzza Stefano , Ganapathisubramani Bharathram
Published: March 2021

Free-stream turbulence characteristics play an important role in the mechanisms of power harvesting for wind turbines. Acquisitions of power and thrust from a model wind turbine of diameter 0.18 m have been carried out in a wind tunnel for a wide range of turbulent base flows, with varying free-stream turbulence intensity in the range between 3% and 16% and integral timescale spanning from 0.1 to 10 times the turbine rotation period. The results demonstrate that power is significantly affected by both the inflow turbulence scales and its intensity, while thrust is scarcely affected by free-stream turbulence. Fluctuations in the generated torques are also measured, with their behavior dominated by the free-stream turbulence scale, and only moderately affected by turbulence intensity. The frequency response of thrust fluctuations has been measured for a selected subset of operating conditions, demonstrating that the turbine thrust is unaffected by high-frequency components in the inflow. Conclusions are drawn on the necessity to match both turbulence intensity and base flow frequency content in wind tunnel studies if realistic results are to be obtained from small-scale studies.
Characterization of an atmospheric pressure air plasma device under different modes of operation and their impact on the liquid chemistry
Authors: Ng Sing Wei , Slikboer Elmar , Dickenson Aaron , Walsh James L. , Lu Peng , Boehm Daniela , Bourke Paula
Published: March 2021

It has been shown that plasma generated in contact with liquid can be tailored to tune the composition of plasma functionalized liquids. For biomedical applications, it is necessary to understand the generation of the plasma treated liquids to modulate the composition and thus the biological response. In this work, two distinct discharge compositions were realized by modifying the location of the ground electrode in a pin-to-liquid plasma system. Through this simple modification to the configurations, the spatiotemporal characteristics of the discharge were significantly affected which, in turn, affected the composition of the generated plasma activated water (PAW). Colorimetric testing of the PAW generated from each system revealed that only one configuration was able to generate PAW with a high concentration of H2O2. Using time-, space-, and wavelength-resolved imaging of excited plasma species [OH, N2 (SPS), N2+ (FNS), and atomic O], the differences in PAW composition were linked to the differences observed in the discharge dynamics between the two configurations.
Classical-to-topological transmission line couplers
Authors: Davis Robert J. , Bisharat Dia'aaldin J. , Sievenpiper Daniel F.
Published: March 2021

Recent advances in topologically robust waveguiding for electromagnetic systems have presented opportunities for improving practical photonic and microwave devices. To bring this rich area of physics within the reach of application, it is critical for such systems to be interfaced with classical, continuous waveguiding, and transmission line technology. This Letter presents a compact, highly efficient transition from a classical metallic transmission line to a topologically nontrivial line wave emulating the quantum spin Hall effect. A zero-gap antipodal slot line is used as the starting transmission line, which is then coupled to the topological metasurface via a field matching procedure. Additional modifications to the interface between the two structures to eliminate unwanted edge coupling improve transmission further. A simulated loss analysis isolates the effect of the transitions from the rest of the structure, showing a loss contribution of only 2.1% per classical-to-topological conversion. Using the transition, a quantitative characterization of the robustness of common topologically protected devices is presented. This design lays the foundation to integrate topologically robust metasurface transmission lines to traditional systems, opening the door to future uses of such structures in systems.
Field-free spin–orbit torque induced magnetization reversal in a composite free layer with interlayer exchange coupling
Authors: Li Zhou , Shi Yinuo , Chi Kequn , Zhang Wenbiao , Feng Xiang , Xing Yun , Meng Hao , Liu Bo
Published: March 2021

We present a field-free spin–orbit torque magnetic random access memory (SOT-MRAM) element using an in-plane ferromagnet (FL1)/coupling layer/perpendicular ferromagnet (FL2) as a composite free layer. By using micromagnetic simulations, we investigate the magnetic switching of the composite free layer in different conditions. Leveraging on interlayer exchange coupling, a field-free and efficient spin–orbit torque-induced reversal of perpendicular magnetization is realized, which can reduce the switching current density of SOT-MRAM. When the current density is increased to a certain value, the oscillations of magnetization are observed. Furthermore, by adjusting the magnetic anisotropy of FL1 and FL2, multilevel magnetization states can be achieved by varying the amplitude of the writing current. This work paves the way toward practical spin–orbit torque-based memory, oscillating, and logic devices.
Exploring topology of 1D quasiperiodic metastructures through modulated LEGO resonators
Authors: Rosa Matheus I. N. , Guo Yuning , Ruzzene Massimo
Published: March 2021

We investigate the dynamics and topology of metastructures with quasiperiodically modulated local resonances. The concept is implemented on a LEGO beam featuring an array of tunable pillar-cone resonators. The versatility of the platform allows the experimental mapping of the Hofstadter-like resonant spectrum of an elastic medium, in the form of a beam waveguide. The non-trivial spectral gaps are classified by evaluating the integrated density of states of the bulk bands, which is experimentally verified through the observation of topological edge states localized at the boundaries. Results also show that the spatial location of the edge states can be varied through the selection of the phase of the resonator's modulation law. The presented results open new pathways for the design of metastructures with functionalities going beyond those encountered in periodic media by exploiting aperiodic patterning of local resonances and suggest a simple, viable platform for the observation of a variety of topological phenomena.
Topological two-dimensional Su–Schrieffer–Heeger analog acoustic networks: Total reflection at corners and corner induced modes
Authors: Coutant Antonin , Achilleos Vassos , Richoux Olivier , Theocharis Georgios , Pagneux Vincent
Published: March 2021

In this work, we investigate some aspects of an acoustic analog of the two-dimensional Su–Schrieffer–Heeger model. The system is composed of alternating cross-sectional tubes connected in a square network, which in the limit of narrow tubes is described by a discrete model coinciding with the two-dimensional Su–Schrieffer–Heeger model. This model is known to host topological edge waves, and we develop a scattering theory to analyze how these waves scatter on edge structure changes. We show that these edge waves undergo a perfect reflection when scattering on a corner, incidentally leading to a new way of constructing corner modes. It is shown that reflection is high for a broad class of edge changes such as steps or defects. We then study the consequences of this high reflectivity on finite networks. Globally, it appears that each straight part of the edges, separated by corners or defects, hosts localized edge modes isolated from their neighborhood.
On the three-dimensional features of a confined slug bubble in a flowing square capillary
Authors: Azadi Reza , Nobes David. S.
Published: March 2021

The motion of long bubbles in tubular capillaries has typically been described by bulk characteristics. However, the dynamics of slug bubbles in square capillaries are more complex due to a corner flow and a thin film flow. The physics can be correctly explained by elucidating local 3D features of the two-phase flow field. To this aim, an experimental study based on particle tracking velocimetry (PTV) and a numerical simulation based on the volume-of-fluid method were conducted to investigate the dynamics of slug bubbles rising in a flowing square capillary with a cross-sectional area of 3 × 3 mm2. To precisely analyze the phases' interaction, interfacial flow data were mapped onto a radial-tangential coordinate system on central and diagonal planes. The simulated interface topology and velocity fields show a good agreement with the experimental PTV data on the central plane, with an absolute error of less than 1.2% for terminal bubble speed. Tangential speeds show their maxima occurring in the channel corners, where pressure is maximum. The thin liquid film flow that occurs where the bubble approaches the wall applies noticeable shear stress on the channel walls, where high and low-pressure regions are generated. Structures of vortices inside the bubble were identified using isosurfaces of the Q-criterion, and their cores were detected based on the parallel vector method. Results reveal a dominant vortex ring adjacent to the liquid film flow and two oblique vortex tubes close to the bubble's nose.
The integrated diagnostic suite of the C-2W experimental field-reversed configuration device and its applications
Authors: Roche T. , Romero J. , Zhai K. , Granstedt E. , Gota H. , Putvinski S. , Smirnov A. , Binderbauer M. W. ,   the TAE Team
Published: March 2021

In the current experimental device of TAE Technologies, C-2W (also called “Norman”), record breaking advanced beam-driven field-reversed configuration (FRC) plasmas are produced and sustained in steady state utilizing variable energy neutral beams (15–40 keV, total power up to 20 MW), advanced divertors, bias electrodes, and an active plasma control system. This fully operational experiment is coupled with a fully operational suite of advanced diagnostic systems. The suite consists of 60+ individual systems spanning 20 categories, including magnetic sensors, Thomson scattering, interferometry/polarimetry, spectroscopy, fast imaging, bolometry, reflectometry, charged and neutral particle analysis, fusion product detection, and electric probes. Recently, measurements of main ion temperatures via a diagnostic neutral beam, axial profiles of energy flux from an array of bolometers, and divertor and edge plasma parameters via an extensive set of electric probes, interferometers, and spectrometers have all been made available. All the diagnostics work together to provide a complete picture of the FRC, fast-ion inventory, and edge plasma details enabling tomographic reconstruction of plasma parameter profiles and real-time plasma control.
The acoustic pressure generated by the cavitation bubble expansion and collapse near a rigid wall
Authors: Gonzalez-Avila Silvestre Roberto , Denner Fabian , Ohl Claus-Dieter
Published: March 2021

We analyze systematically the acoustic transients emitted during the collapse of a laser-induced cavitation bubble for 0.4≤γ≤5.2. γ is the standoff parameter, the ratio of the distance between the bubble's nucleation place and its maximum size. At the bubble collapse, the acoustic signals recorded contain several pressure peaks with rising times as fast as 18 ns. The time delay, Δt, between these peaks is a few hundred nanoseconds apart for bubbles nucleated close to the boundary and decreases with γ. The pressure maxima correspond to shock fronts emitted around the time the bubble reaches its minimum volume and is correlated with the high-speed video recordings of the bubble dynamics. We also show that the amplitude ratio of the first to second acoustic transient is strongly dependent on γ. The experimental results are complemented with numerical simulations based on the Volume-of-Fluid method. The simulated results help clarify the physical mechanisms leading to the generation of acoustic transients and unveil in detail the morphology of the bubble approaching its minimum volume, a feature that cannot be resolved with the high-speed data. Furthermore, the numerical results reveal that the impact of the liquid jet on the rigid wall ensues a local increase in pressure over a significant time period, contrary to the shock wave formed during bubble collapse, which produces a sharp transient pressure peak that propagates radially outwards along the rigid wall. We also discuss the validity and shortcomings of the simulation and how to improve them in the future.
Computer simulation of the SARS-CoV-2 contamination risk in a large dental clinic
Authors: Komperda Jonathan , Peyvan Ahmad , Li Dongru , Kashir Babak , Yarin Alexander L. , Megaridis Constantine M. , Mirbod Parisa , Paprotny Igor , Cooper Lyndon F. , Rowan Susan , Stanford Clark , Mashayek Farzad
Published: March 2021

COVID-19, caused by the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) virus, has been rapidly spreading worldwide since December 2019, causing a public health crisis. Recent studies showed SARS-CoV-2's ability to infect humans via airborne routes. These motivated the study of aerosol and airborne droplet transmission in a variety of settings. This study performs a large-scale numerical simulation of a real-world dentistry clinic that contains aerosol-generating procedures. The simulation tracks the dispersion of evaporating droplets emitted during ultrasonic dental scaling procedures. The simulation considers 25 patient treatment cubicles in an open plan dentistry clinic. The droplets are modeled as having a volatile (evaporating) and nonvolatile fraction composed of virions, saliva, and impurities from the irrigant water supply. The simulated clinic's boundary and flow conditions are validated against experimental measurements of the real clinic. The results evaluate the behavior of large droplets and aerosols. We investigate droplet residence time and travel distance for different droplet diameters, surface contamination due to droplet settling and deposition, airborne aerosol mass concentration, and the quantity of droplets that escape through ventilation. The simulation results raise concerns due to the aerosols' long residence times (averaging up to 7.31 min) and travel distances (averaging up to 24.45 m) that exceed social distancing guidelines. Finally, the results show that contamination extends beyond the immediate patient treatment areas, requiring additional surface disinfection in the clinic. The results presented in this research may be used to establish safer dental clinic operating procedures, especially if paired with future supplementary material concerning the aerosol viral load generated by ultrasonic scaling and the viral load thresholds required to infect humans.
Enhancement of the nonlinear magnetoelectric effect in a ferromagnet-piezoelectric heterostructure due to nonlinearity of magnetization
Authors: Burdin Dmitri. A. , Ekonomov Nikolai A. , Vopson Melvin M. , Fetisov Yuri K.
Published: March 2021

We describe theoretically and experimentally a previously unobserved mechanism for the induction of the nonlinear magnetoelectric response in ferromagnet-piezoelectric multiferroic composites. We show that contributions to the nonlinear magnetoelectric effects come not only from the nonlinearity of the magnetostriction coefficient on the dc magnetic field but also from the nonlinear hysteretic dependence of the magnetization of the magnetic phase within the composite. The nonlinearity of the magnetization leads to the self-generation of an additional ac magnetic field oscillating at twice the frequency of the excitation field. In turn, this leads to the strain-mediated activation of the piezocomponent, generating a voltage output response and doubling its frequency relative to that of the excitation field. For the PbZrTiO3/FeBSiC test sample examined in this study, we determined that this mechanism is responsible for an additional contribution of ∼14% to the nonlinear magnetoelectric effect.
Bright room temperature near-infrared single-photon emission from single point defects in the AlGaN film
Authors: Xue Yingxian , Chen Feiliang , Fang Zhiyun , Zhang Shiyu , Li Qian , Li Mo , Kang Jianbin , Zhang Jian , Shen Si , Wu Botao , Wu E
Published: March 2021

Near-infrared (NIR) single-photon source plays a key role in a wide range of applications in quantum technology. In particular, in quantum communication, the NIR wavelength operation perfectly matches the relatively low-attenuation transmission window of the optical fiber, which attracts more and more research interest. Here, we report the room temperature single-photon emission from single point defects in the aluminum gallium nitride (AlGaN) film. The obtained single-photon emission covers from 720 to 930 nm and exhibits highly linear polarization and high photon brightness. This may provide a platform for future integrated on-chip quantum photonic devices.
The influence of thermal annealing on the photoconducting properties of BaSnO3 films
Authors: Bridoux G. , Ferreyra J. M. , Guimpel J. , Nieva G. , Villafuerte M.
Published: March 2021

Starting from high-quality oxygen-deficient BaSnO3 films, we have monitored the evolution of their electrical conducting and photoconducting properties after subsequent post-thermal annealing in oxygen. In this way, we have been able to modify the electrical conductivity of the film by at least three orders of magnitude (from 18.2 to 0.013 Ω−1 m−1) by simply reducing the oxygen vacancies concentration after each thermal annealing. Even though the film holds its semiconducting-like behavior, we have observed a modification of the hopping parameters concomitant with a decrease in the Fermi energy level as the electrical conductivity is reduced. Similarly, the effective energy gap extracted from photoconductance spectroscopy measurements decreases as the Fermi energy level decreases suggesting the presence of in-gap states generated by oxygen vacancies. A direct energy bulk gap value of (3.8±0.1) eV was obtained. While the photoconductivity increases from ≃4.6 to 73%, its slow time constants become less dominant as the electrical conductivity is decreased in accordance with a reduction of the oxygen vacancies density, which play a key role as electron-traps.
Band point algorithms for measuring diffraction pattern parameters in laser ektacytometry of red blood cells
Authors: Nikitin S.Yu. , Ustinov V.D. , Shishkin S.D.
Published: March 2021

We consider the issues of measuring the deformability of red blood cells by the method of laser diffractometry in shear flow (ektacytometry). The measurement procedure is optimised taking into account the finite resolution of the video recording system of the laser ektacytometer. An algorithm is proposed that allows one to determine with high accuracy the diffraction pattern parameters necessary for measuring the characteristics of the erythrocyte deformability distribution.
Modulation and amplification of wave packets in amplifiers with a travelling refractive-index wave
Authors: Zolotovskii I.O. , Kadochkin A.S. , Lapin V.A. , Sannikov D.G. , Yavtushenko M.S.
Published: March 2021

We study the conditions of frequency modulation, spectral broadening, and amplification of a Gaussian pulse – a whispering-gallery-mode (WGM) wave packet (WP) – propagating along a spiral trajectory on the surface of an active cylindrical optical waveguide, in which a travelling refractive-index wave (TRIW) is generated. Analytical expressions are obtained for the dependences of the duration, chirp, and spectral width on the distance travelled by the pulse along the waveguide, as well as on the parameters of the waveguide and the radiation launched into it. It is shown that the interaction of a wave packet with the TRIW leads to a strong frequency modulation of the amplified pulse with the conserved linearity of the chirp. It is demonstrated that this circumstance can be used to generate pico- and subpicosecond pulses with peak powers above 100 kW.
Investigation on laser selective photoionisation of the 177mLu isomer
Authors: D’yachkov A.B. , Gorkunov A.A. , Labozin A.V. , Makoveeva K.A. , Mironov S.M. , Firsov V.A. , Tsvetkov G.O. , Panchenko V.Ya.
Published: March 2021

The selectivity of laser photoionisation of 177mLu nuclear isomer with respect to natural isotopes has been studied for the first time using a three-stage lutetium photoionisation scheme

.
Tunable low-coherence light source with high spectral brightness
Authors: Shidlovskii V.R. , Shramenko M.V. , Yakubovich S.D.
Published: March 2021

Operation of a tunable tandem-type low-coherence light source with high spectral brightness based on commercially available optical elements (superluminescent diode, semiconductor optical amplifier, and bulk dwiffraction grating) is studied experimentally. A unique combination of the output source characteristics, namely, a spectral power density of 36 mW nm−1, a wavelength tuning range of 35 nm (834 – 869 nm), and a more than 20-dB excess of the central peak intensity over the superluminescent pedestal, is experimentally obtained. It is shown that the output radiation spectrum with a width of 1.4 nm has a smooth bell-shaped profile with side lobes lying below the superluminescent pedestal. It is proved that such a light source is of practical interest for various applications.
Dynamics of laser ablation of gold in melts of inorganic salts
Authors: Zhilnikova M.I. , Rakov I.I. , Uvarov O.V. , Shafeev G.A.
Published: March 2021

Nanosecond laser ablation of a bulk gold target in a melt of a sodium nitrate salt is investigated. It is shown that the form of plasma plumes on the target surface during ablation depends on the laser beam scan rate. The extinction spectra of sodium nitrate composites with gold nanoparticles during solidification is analysed.
Intraspecific variation in testis organisation and sperm head morphology of the delicate mouse (
Authors: Peirce Eleanor , Moya-Smith TlalliAztlan , Leigh Chris , Breed William
Published: March 2021

The delicate mouse (Pseudomys delicatulus) ranges from Queensland to northern Western Australia. In this study the morphology of the cellular organisation of the testis and cauda epididymal spermatozoa are compared. Individuals from the mainland of the Northern Territory and Western Australia invariably have only 60–70% of the testes composed of seminiferous tubules with the interstitial tissue between the tubules containing abundant lipid rich Leydig cells, whereas the cauda epididymal sperm have highly polymorphic, often pear-shaped, heads and basally attached tails. In individuals from Queensland the seminiferous tubules make up approximately 80% of the testis, whereas in the cauda epididymides the sperm populations are generally less variable and have bilaterally flattened heads with the tail attached to the lower concave surface. These differences in the morphology of the delicate mouse testis and spermatozoa in these two geographic regions suggest differences in intensity of intermale sperm competition, with individuals from northern Western Australia and the mainland of the Northern Territory exhibiting monogamy whereas those from Queensland may exhibit some degree of intermale sperm competition and hence possibly have a polyandrous or promiscuous mating system. These findings support the suggestion that P. delicatulus, as currently recognised, contains at least one cryptic species.
Weather systems and extreme rainfall generation in the 2019 north Queensland floods compared with historical north Queensland record floods
Authors: Callaghan Jeff
Published: March 2021

Earlier papers have addressed floods from warm-air advection (WAA) in southeast Australia and around the globe, and extreme rainfall in US hurricanes and Australian tropical cyclones (TCs). This is the first paper to address the WAA phenomena in causing monsoon and TC floods and in TC-like systems which develop over the interior of northern Australia. The inland events help explain Australia’s worst tropical flooding disaster in 1916. A disastrous series of floods during late January and early February 2019 caused widespread damage in tropical north Queensland both in inland regions and along the coast. This occurred when some large-scale climate influences, including the sea surface temperatures suggested conditions would not lead to major flooding. Therefore, it is important to focus on the weather systems to understand the processes that resulted in the extreme rainfall responsible for the flooding. The structure of weather systems in most areas involved a pattern in which the winds turned in an anticyclonic sense as they ascended from the low to middle levels of the atmosphere (often referred to as WAA) which was maintained over large areas for 11 days. HYSPLIT air parcel trajectory observations were employed to confirm these ascent analyses. Examination of a period during which the heaviest rain was reported and compared with climatology showed a much stronger monsoon circulation, widespread WAA through tropical Queensland where normally its descending equivalent of cold-air advection is found, and higher mean sea level pressures along the south Queensland coast. The monsoon low was located between strong deep monsoon westerlies to the north and strong deep easterlies to the south which ensured its slow movement. This non-TC event produced heavy inland rainfall. Extreme inland rainfall is rare in this region. Dare et al. (2012), using data from 1969/70 to 2009/10, showed that over north Queensland non-TC events produced a large percentage of the total rainfall. The vertical structure associated with one of the earlier events that occurred in 2008 had sufficient data to detect strong and widespread WAA overlying an onshore moist tropical airstream. This appears to have played a crucial role in such extreme rainfall extending well inland and perhaps gives insight to the cause of a 1916 flooding disaster at Clermont which claimed around 70 lives. Several other events over the inland Tropics with strong WAA also help explain the 1916 disaster.
The consequences of online partisan media
Authors: Guess Andrew M. , Barberá Pablo , Munzert Simon , Yang JungHwan
Published: March 2021

Significance

Popular wisdom suggests that the internet plays a major role in influencing people’s attitudes and behaviors related to politics, such as by providing slanted sources of information. Yet evidence for this proposition is elusive due to methodological difficulties and the multifaceted nature of online media effects. This study breaks ground by demonstrating a nudge-like approach for exploring these effects through a combination of real-world experimentation and computational social science techniques. The results confirm that it is difficult for people to be persuaded by competing media accounts during a contentious election campaign. At the same time, data from a longer time span suggest that the real consequence of online partisan media may be an erosion of trust in mainstream news.
Upgraded CRISPR/Cas9 tools for tissue-specific mutagenesis in
Drosophila
Authors: Koreman Gabriel T. , Xu Yineng , Hu Qinan , Zhang Zijing , Allen Sarah E. , Wolfner Mariana F. , Wang Bei , Han Chun
Published: March 2021

Significance

Understanding the mechanisms of development and disease often requires the ability to remove gene function from specific tissues. The CRISPR/Cas9 system can mutate any gene by Cas9-mediated DNA cutting, but current tissue-specific CRISPR/Cas9 tools still have much room for improvement. Here, we report a set of tools that significantly improve the efficiency, flexibility, and analytic power of tissue-specific CRISPR/Cas9 in
Drosophila
. Proper components of these tools can be adopted to achieve the highest mutagenic efficiency in the germline or in somatic tissues, to label mutant cells genetically, or to convert existing Gal4 lines into tissue-specific Cas9 lines. These tools can be adapted easily to other organisms.
miR
-
218
-
2
regulates cognitive functions in the hippocampus through complement component 3–dependent modulation of synaptic vesicle release
Authors: Lu Si-Yao , Fu Chong-Lei , Liang Liang , Yang Bo , Shen Wei , Wang Qiu-Wen , Chen Yun , Chen Yan-Fen , Liu Yao-Nan , Zhu Lin , Zhao Jieqing , Shi Wei , Mi Shuangli , Yao Jun
Published: March 2021

Significance

Several neurodegenerative and neuropsychiatric disorders with cognitive symptoms show an abnormal expression of microRNA-218 (miR-218). In this study, we demonstrated that miR-218 regulated presynaptic functions and learning related behaviors through targeting the 3′-untranslated region (UTR) of the mRNA of complement component 3 (C3), a central component of the immune system. This finding may represent a common mechanism for the defective cognition of multiple neuronal disorders with miR-218 deficits and provide a strategy for the development of new therapy.
Virus-induced cell gigantism and asymmetric cell division in archaea
Authors: Liu Junfeng , Cvirkaite-Krupovic Virginija , Baquero Diana P. , Yang Yunfeng , Zhang Qi , Shen Yulong , Krupovic Mart
Published: March 2021

Significance

Studies on bacterial and eukaryotic viruses have revealed a range of strategies used by viruses to subdue host cells for efficient virus replication. How archaeal viruses interact with their hosts remains largely unknown. We characterize a new strategy employed by a nonlytic archaeal virus STSV2 to transform its host into a giant virion-producing factory, whereby the virus infection blocks normal cell division by binary fission, leading to gradual cell growth to unprecedented sizes. The giant infected cells divide asymmetrically by budding, replenishing the pool of susceptible hosts. Thus, although tinkering with the cell cycle is a common practice among evolutionarily unrelated viruses from different domains of life, the mechanisms and manifestation of these actions can be highly diverse and unexpected.