bluuebunny/crossref_metadata_2025 huggingface dataset:
A 564 W QCW Thulium Fiber Oscillator Pumped at 793 nm
Authors: Limongelli Julia R. , Allee Ezra , Bieniek Matthew , Setzler Scott D. , Bruce Kevin , Fanning Geoff , McCal Dennis , Randall Matthew
Published: January 2021

A 1940 nm thulium fiber oscillator producing >550 peak watts at 10% duty cycle is presented. The laser, pumped by seven high-brightness fiber-coupled 793 nm diodes, is single transverse mode at 45% optical conversion efficiency.
Unified joint reconstruction approach for random illumination microscopy: retraction
Authors: Liu Penghuan
Published: January 2021

The referenced article [Biomed. Opt. Express 11, 5147 (2020)10.1364/BOE.399547] has been retracted by the author.
Coherent pulses from seeded Free Electron Lasers: the experience at FERMI with high gain harmonic generation and echo enabled harmonic generation
Authors: Allaria E.
Published: January 2021

We report here on the recent results from operations of the FERMI Free Electron Lasers for users including the most advanced schemes recently developed and the first demonstration of Echo Enabled Harmonic Generation in the soft-X-ray.
Research and Development of Attosecond VUV and X-ray Sources Driven by Mid-Infrared FEL Oscillators
Authors: Hajima Ryoichi , Nagai Ryoji , Kawase Keigo , Ohgaki Hideaki , Zen Heishun , Hayakawa Yasushi , Sakai Takeshi , Sumitomo Yoske , Shimada Miho , Miyajima Tsukasa
Published: January 2021

A research program towards an attosecond photon source based on high-harmonic generation driven by mid-infrared FEL oscillators has been established. We present the scope and the current status of the research program.
High Power Gamma Flare Generation in Multi-Petawatt Laser-Matter Interaction
Authors: Bulanov S. V. , Hadjisolomou P. , Khikhlukha D. R. , Sasorov P. V. , Klimo O. , Korn G. , Lezhnin K. V. , Esirkepov T. , Pirozhkov A. S. , Kawachi T. , Tsygvintsev I. P. , Gasilov V. A.
Published: January 2021

Using QED PIC and hydrodynamic simulations, we optimize the -flare generation scheme from the high power laser interaction with tailored target showing the efficient conversion of the laser pulse energy to -photons.
Relativistic Flying Mirrors as a Compact Source of Coherent Short-Wavelength Radiation
Authors: Valenta Petr , Esirkepov Timur Zh. , Koga James K. , Pirozhkov Alexander S. , Kando Masaki , Kawachi Tetsuya , Liu Yung-Kun , Fang Patrick , Chen Pisin , Mu Jie , Korn Georg , Klimo Ondřej , Bulanov Sergei V.
Published: January 2021

Relativistic mirrors in laser plasmas offer a promising way for development of compact and tunable sources of coherent short-wavelength radiation. Here we investigate recoil effects on reflection of high-intensity laser pulses from such mirrors.
Stepwise Development to Realize the High Power EUV-FEL Light Source
Authors: Kato Ryukou , Sakai Hiroshi , Tsuchiya Kimichika , Tanimoto Yasunori , Honda Yosuke , Miyajima Tsukasa , Shimada Miho , Nakamura Norio , Kawata Hiroshi
Published: January 2021

A high repetition rate EUV-FEL is one of the promising candidates for the future high power EUV light source more than 1 kW for future lithography. The design work on the FEL light source and the stepwise development procedure have been proposed elsewhere. Last fiscal year, KEK obtained a funding entitled "New laser technology development for processing laser" from NEDO to develop the high average power mid-infrared FEL. This FEL corresponds to the important stepwise development for EUV-FEL, too. At the conference, the present status of the project and the relationship of the technical development between present mid-infrared FEL and EUV-FEL will be presented.
Towards High Harmonic Generation in Laser-Produced Plasma
Authors: Schulte Amelie , Mathijssen Jan , Eikema Kjeld , Witte Stefan
Published: January 2021

We are developing a pump-probe experiment in which high harmonics are generated in a tin plasma and analysed in a spectrometer to investigate the spatial and temporal distribution of different charge states in the plasma.
Hard X-ray in-situ full-field microscopy for material science applications
Authors: Snigireva I. , Falch K. V. , Casari D. , Di Michiel M. , Detlefs C. , Mathiesen R. , Snigirev A.
Published: January 2021

Hard X-ray transmission microscopy based on refractive optics is applied as a tool in material science to study microstructure in two or three dimensions with spatial resolution of 100nm. A few possible application areas for the microscope are illustrated.
Fundamental Research Activities of EUV Lithography at NewSUBARU Synchrotron Light Facility
Authors: Watanabe Takeo , Harada Tetsuo
Published: January 2021

The recent EUVL activities of resists, masks, and optics at NewSUBARU Synchrotron Light Facility are introduced. In addition, the capabilities of the shortening the wavelength to 6.75 nm with high-power EUV source are also discussed.
Second-Harmonic Generation of Spatiotemporal Optical Vortices
Authors: Hancock S.W. , Zahedpour S. , Milchberg H.M.
Published: January 2021

Spatiotemporal optical vortices (STOVs) are a new type of optical orbital angular momentum (OAM) residing in the space-time domain. Here we examine, through experiment and simulation, how STOV OAM is transformed in second-harmonic generation.
Development of Gas-Discharge X-ray Sources for Nanotomography at “Burtsev Laboratory” LLC
Authors: Samokhvalov A. , Bolshakov E. , Bronzov T. , Sergushichev K. , Smirnov A. , Eliseev S. , Timshina M. , Belsky D. , Letunovskaya M. , Burtsev V.
Published: January 2021

Overview of development of compact gas-discharge X-ray sources in the “water window” range undergoing at “Burtsev Laboratory” LLC is given. General description of the experimental prototype under development and results of experimental investigations are presented.
A microscopic thery for selection rules of solid-state high-harmonic generation based on time-dependent Schrödinger equation
Authors: Shinohara Yasushi
Published: January 2021

We propose a microscopic description of the crystal symmetry deriving high-order harmonic generation selection rules by using a theory not relying on the perturbative expansion. The results give us how the contributions of different k-points forms the selection rule.
Efficient sub-MeV ion generation by standing wave excitation of ionized gases
Authors: Turnár Szabolcs , Tibai Zoltán , Mechler Mátyás I. , Pálfalvi László , Almási Gábor , Hebling János
Published: January 2021

Acceleration of ions by Coulomb explosion following ripping the electrons from gas plasmas by ultrafast standing waves are numerically investigated. Generation with 1.3 % efficiency of sub-MeV energy deuterons with 0.8 nC bunch charge is predicted.
Probing the crystal structure of ZnTe with high-order harmonic generation
Authors: Faccialà Davide , Pusala Aditya , Geetha Prabhash Prasannan , Musheghyan Mikayel , Crippa Gabriele , Ciriolo Anna G. , Devetta Michele , Assion Andreas , Cinquanta Eugenio , Stagira Salvatore , Vozzi Caterina
Published: January 2021

We generated high-order harmonics in ZnTe crystal driven by a mid-IR optical parametric amplifier. The dependence of the harmonic signal as a function of the crystal orientation is investigated and interpreted within the re-collision framework.
Generation of elliptically polarized high-order harmonics exposing aligned diatomic molecules to orthogonally polarized two-color fields
Authors: Habibović Dino , Becker Wilhelm , Milošević Dejan B.
Published: January 2021

High-harmonic generation by aligned diatomic molecules in orthogonally po-larized two-color laser fields is considered using the molecular strong-field approximation. Regions of the parameter space with large harmonic ellipticity are identified.
Interferometric measurements of near-critical plasma density in a supersonic gas jet
Authors: Railing L. , Le M. , Salehi F. , Milchberg H.M.
Published: January 2021

We demonstrate interferometric measurements of plasma formed by a laser pulse above the relativistic self-focusing power for near-critical density plasmas using a third harmonic probe.
LWFA driven hard X-ray sources at ELI Beamlines
Authors: Chaulagain U. , Karatodorov S. , Lamac M. , Raclavsky M. , Kozlova M. , Weber S. A. , Nejdl J.
Published: January 2021

We report on hard X-ray sources with broadband spectrum ranging from a few keV to MeV that are based on the relativistic electrons driven by the state-of-the-art high-power laser system at ELI Beamlines facility.
Numerical simulations of terahertz pulse generation with two-color laser pulses in the 2.15-15.15 μm spectral range
Authors: Flender Roland , Borzsonyi Adam , Kiss Balint , Chikan Viktor
Published: January 2021

The generation of terahertz pulses from two-color mid-infrared pulses is numerically investigated. The central wavelength of the fundamental laser pulse is varied from 2.15 µm up to 15.15 µm resulting the most efficient THz generation at 14.30 µm.
Waveguide structure based tabletop electron acceleration setup using THz pulses
Authors: Turnár Szabolcs , Kovács Bálint , Almási Gábor , Hebling János , Tibai Zoltán
Published: January 2021

In our numerical simulations the acceleration of electron bunches in THz pulse-driven waveguide structures has been investigated. Acceleration of electron bunches with 1fC bunch charge up to 46 keV energy was predicted at 50 mm.
Dose Characterization of the 1 kHz Repetition Rate High-Z Metal X-Ray Source Driven by 20 mJ Femtosecond Pulses
Authors: Reklaitis Jonas , Barkauskas Vytenis , Plukis Artūras , Kovalevskij Vitalij , Gaspariūnas Mindaugas , Germanas Darius , Garankin Jevgenij , Stanislauskas Tomas , Jasiūnas Kestutis , Remeikis Vidmantas
Published: January 2021

The TW-class 850 nm, 10 fs laser was used to generate the hard X-ray in high-Z targets. The dose rate up to 25 µSv/h was measured using the experimental induced dose measurements and modeling.
X-ray Pulse Emission of Alkali Metal Halide Salts Irradiated by Femtosecond Laser Pulses
Authors: Koroliov Anton , Varsockaja Karolina , Reklaitis Jonas , Plukis Artūras , Remeikis Vidmantas
Published: January 2021

We have measured X-ray radiation spectra of alkali halide salts as targets for X-ray generation with typical X-ray flux of 106 ph./s. We were able to confirm that there was enough electrons with energy higher than 33 keV.
High repetition rate OPCPA driving an attosecond pump-probe beamline
Authors: Furch Federico J. , Witting Tobias , Osolodkov Mikhail , Schell Felix , Schulz Claus P. , Vrakking Marc J. J.
Published: January 2021

A high power optical parametric amplifier operating at 100 kHz repetition rate has been integrated into an attosecond pump-probe beamline. Attosecond pulses with high photon flux are generated and characterized in pump-probe experiments.
High repetition rate CEP-stable Yb-doped laser source for attoscience
Authors: Natile Michele , Golinelli Anna , Guichard Florent , Hanna Marc , Zaouter Yoann , Chiche Ronic , Georges. Patrick
Published: January 2021

We report on the CEP-stabilization of an ultrashort pulses Yb-doped source delivering 75 microjoules, 60 fs at 100 kHz with a measured every shot CEP noise lower than 320 mrad over 1s.
Readiness of L1 ALLEGRA Laser System for User Operation at ELI Beamlines
Authors: Bakule Pavel , Antipenkov Roman , Novák Jakub , Batysta František , Boge Robert , Green Jonathan Tyler , Hubka Zbyněk , Greco Michael , Indra Lukáš , Špaček Alexandr , Naylon Jack Alexander , Majer Karel , Mazůrek Petr , Erdman Emily , Šobr Václav , Tykalewicz Boguslaw , Mazanec Tomáš , Strkula Petr , Rus Bedřich
Published: January 2021

We report on the current state of readiness of the 1 kHz, 15 fs L1 ALLEGRA laser system for long term reliable operation driving user experiments based on HHG. The highly automated system, based on short pulse OPCPA, currently generates pulses with energy of 30 mJ at central wavelength of 820 nm.
Inter-atomic distance effects on high-harmonic generation by one-dimensional array
Authors: Tani Mizuki , Shinohara Yasushi , Sato Takeshi , Ishikawa Kenichi L.
Published: January 2021

We theoretically investigate how high-harmonic spectra depend on inter-atomic distance (IAD), using a one-dimensional model crystal. We identify two characteristic IAD regions and find drastic transitions between a solid-like system and a gas-like system.
Laser-plasma acceleration with superluminal laser pulses
Authors: Thaury C. , Caizergues C. , Oubrerie K. , Smartsev S. , Malka V. , Gautier J. , Phuoc K. Ta , Goddet J. P. , Tafzi A.
Published: January 2021

We propose a new acceleration concept, based on the use of diffraction-free superluminal laser pulses, which allows to cope with the three phenomena that limit the beam energy in a laser-plasma accelerator.
Two-Stage Nonlinear Compression of High Intensity Pulses
Authors: Ginzburg Vladislav , Yakovlev Ivan , Zuev Alexandr , Korobeynikova Anastasia , Kochetkov Anton , Kuzmin Alexey , Mironov Sergey , Shaykin Andrey , Shaikin Ilya , Khazanov Efim
Published: January 2021

We demonstrated two-stage laser pulse compression via self-phase modulation and dispersion compensation by chirped mirrors. 250-TW-pulse was compressed from 70fs to 14fs. This technique may be applied to any high power laser.
MLD vs. Transmission Gratings for the Highest-Efficiency, Most-Compact Pulse Compressors
Authors: Erdogan T.
Published: January 2021

Contrary to popular belief MLD gratings can be designed with a wide range of periods to provide the highest overall efficiency pulse compressors that are as compact and flexible as those based on transmission gratings.
High Harmonic Generation on Noble Gas Clusters
Authors: Bódi Balázs , Aladi Márk , Rácz Péter , Földes István B. , Dombi Péter
Published: January 2021

The ellipticity dependence of HHG from noble gas clusters was measured for different cluster sizes. Results show that electrons recombine with the parent ion only and the charge does not delocalize in the cluster.
10 PetaWatt Laser System for Extreme Light Physics
Authors: Lureau François , GhuillaumeMatras  , Chalus Olivier , Derycke Christophe , Radier Christophe , Casagrande Olivier , Ricaud Sandrine , Boisson Christophe Simon
Published: January 2021

We present results obtained on the first 10PW laser at ELI-NP installation. We demonstrated a laser system delivering pulses at 1 shot/min with a peak power of 10.9PW.
Sub-Cycle Infrared Pulses Through Soliton Self-Compression in Hollow Capillary Fibres
Authors: Brahms Christian , Belli Federico , Travers John C.
Published: January 2021

We demonstrate the generation of sub-cycle pulses in the infrared (1340 nm) with a peak power of 27 GW using soliton self-compression. The envelope duration of 2 fs corresponds to an 840 as field transient.
Every single-shot CEP drift detection for near-infrared lasers with modified TOUCAN method
Authors: Máté Kurucz , Szabolcs Tóth , János Csontos , Bálint Kiss , Cormier Eric
Published: January 2021

The original TOUCAN device is capable of single-shot CEP drift measurement of ~3 µm lasers at arbitrary repetition rate. We have expanded this technique for near-infrared lasers and crosschecked results with a traditional measurement method.
Laser-driven Ion Acceleration and Applications at ELI
Authors: Margarone D. , Cirrone G. A. P.
Published: January 2021

The ELIMAIA beamline, recently installed at ELI-Beamlines, aims at offering short ion bunches accelerated by high repetition-rate, PW-class lasers to users from multidisciplinary fields by using innovative and compact ion beam transport and dosimetry approaches.
Three-dimensional photonic crystal short-pillar architecture for high-performance optical biosensing
Authors: Vujic Dragan , John Sajeev
Published: January 2021

Numerical analysis of optical biosensors made of very short-pillar (only one or two lattice constants high) liquid-infiltrated photonic crystals is presented. The small pillar height makes these photonic crystals amenable to fabrication by techniques such as nanoimprinting. Our biosensors can detect at least three different analytes (disease markers), individually or combinatorially in a single spectroscopic measurement. The resonance linewidths of our proposed device are narrow enough to accurately identify the relative concentrations of analytes within the biofluid, enabling our device to provide both qualitative and quantitative disease diagnoses. The minimal volume of fluid sample required for diagnosis is set by the micrometer-scale lattice constant of the photonic crystal. Using finite-difference time-domain simulations, we present detailed spectral characteristics for all possible combinations of analyte attachment to the photonic crystal nanopillars.
Multi-gas spectroscopy using tailored mid-IR dispersive wave generated in Si3N4 waveguide
Authors: Tagkoudi Eirini , Grassani Davide , Yang Fan , Brès Camille-Sophie
Published: January 2021

We demonstrate simultaneous detection of acetylene, methane and ethane using milliwatt-level dispersive-wave generated in a Si3N4 waveguide covering 2900 cm-1 -3380 cm-1 spectral region. This simple mid-IR absorption spectroscopy scheme achieves hundreds of ppm detection limit.
Mid-infrared Quantum Interference and Polarization Entanglement
Authors: Shields Taylor , Prabhakar Shashi , Dada Adetunmise , Ebrahim Mehdi , Taylor Gregor G. , Morozov Dmitry , Erotokritou Kleanthis , Miki Shigehito , Yabuno Masahiro , Terai Hirotaka , Gawith Corin , Kues Michael , Caspani Lucia , Hadfield Robert H. , Clerici Matteo
Published: January 2021

We demonstrate two-photon interference and polarization entanglement at 2090 nm, constituting a crucial leap towards free-space mid-infrared quantum communication systems in a spectral region with high atmospheric transparency and reduced solar background.
High-pulse-energy actively Q-switched polarization-maintaining Tm3+-doped silica fiber laser
Authors: Schneider Julian , Forster Patrick , Eichhorn Marc , Kieleck Christelle
Published: January 2021

A diode-pumped Q-switched thulium-doped fiber laser is reported providing 43 ns short pulses with pulse energies of 800 µJ at a wavelength of 2050 nm.
Midwave-infrared OPCPA driver for femtosecond hard X-ray generation at a 1 kHz repetition rate
Authors: Griebner Uwe , von Grafenstein Lorenz , Bock Martin , Koc Azize , Hauf Christoph , Woerner Michael , Zawilski Kevin , Schunemann Peter , Elsaesser Thomas
Published: January 2021

A compact OPCPA system delivering sub-100 fs pulses with 3 mJ energy at 5 µm using a 2-µm CPA pump source is presented and its application as driver for hard x-ray generation is reported.
Enhanced Nonlinear Pulse Compression Sign-Alternating Dispersion Waveguides at Low Input Peak Powers
Authors: Zia Haider
Published: January 2021

We show that repeated sign-alternating dispersion waveguides are robust to higher-order spectral phase effects, obtaining large bandwidths, at low input peak-powers, with near-parabolic phase for pulse compression. A Novel pulse compression technique is also presented.
Terahertz Driven Electron and X-ray Sources
Authors: Kärtner Franz X.
Published: January 2021

A terahertz accelerator technology for compact electron and X-ray sources based on efficient laser generated high energy terahertz pulses is introduced. Terahertz guns and accelerators are demonstrated and implementation of electron and X-ray sources is discussed.
Design and development of a low-cost tunable midinfrared light source based on single pass optical parametric generation in a quasi-phase-matched lithium niobate crystal
Authors: Ashik A. S. , Tidemand-Lichtenberg Peter , Pedersen Christian
Published: January 2021

We report on the development of a low-cost tunable mid-IR light source using a single pass optical parametric generation system. A passively Q-switched laser, delivering high peak power, pumps the periodically poled lithium niobate crystal.
New coherent sources for mid infrared spectroscopic applications
Authors: Harren Frans J.M.
Published: January 2021

An overview will be given on the new coherent sources that became available and can fulfil the needs for analytical spectroscopy in the mid infrared wavelength region. Recent highly-visible applications will be presented.
Time-Resolved Mid-Infrared Dual-Comb Spectroscopy Based on a Two-Crystal Optical Parametric Oscillator
Authors: Khodabakhsh Amir , Abbas Muhammad A. , Mandon Julien , Pan Qing , Harren Frans J. M.
Published: January 2021

We present a time-resolved mid-infrared dual-comb spectrometer based on a femtosecond two-crystal singly resonant optical parametric oscillator, suitable for monitoring the dynamics of fast chemical reactions in millisecond and microsecond time-scales.
High-Quality Mid-Infrared Dual-Comb Spectroscopy Based on a Two-Crystal Optical Parametric Oscillator
Authors: Abbas Muhammad Ali , Mandon Julien , Pan Qing , Harren Frans J. M. , Khodabakhsh Amir
Published: January 2021

A mid-infrared dual-comb spectrometer is presented based on a femtosecond two-crystal singly resonant optical parametric oscillator and a reference absorption cell for frequency calibration, achieving a spectral resolution of 6 GHz in 120 µs.
Measurement of Effective Four-Photon Absorption in Semiconductors
Authors: Polónyi Gy. , Monoszlai B. , Nugraha P. S. , Tóth Gy. , Pálfalvi L. , Nasi L. , Ollmann Z. , Rohwer E. J. , Gäumann G. , Feurer T. , Hebling J. , Fülöp J. A.
Published: January 2021

Effective four-photon absorption coefficients and their anizotropy were meas-ured in semiconductors (ZnTe, GaP) by z-scan technique in infrared wavelength.
Simple, Robust Mid-infrared Frequency Combs Generated From Few-cycle Near-infrared Pulses
Authors: Lind Alexander J. , Kowligy Abijith S. , Timmers Henry , Cruz Flavio C. , Silfies Myles C. , Allison Thomas K. , Diddams Scott A.
Published: January 2021

We demonstrate a simple scheme for mid-infrared frequency comb generation from 3-5.5 μm utilizing intra-pulse difference frequency generation in periodically poled lithium niobate. Numerical modeling shows a route to few-cycle pulses centered at 4 µm.
Mid-infrared frequency comb covering the 6.5 – 9 μm range with active output power stabilization
Authors: Krzempek Karol , Tomaszewska Dorota , Głuszek Aleksander , Hudzikowski Arkadiusz , Martynkien Tadeusz , Mergo Paweł , Sotor Jarosław , Foltynowicz Aleksandra , Soboń Grzegorz
Published: January 2021

We report a compact, actively stabilized fiber-based mid-infrared frequency comb source covering the 6.5 – 9 μm wavelength range with up to 5 mW of average output power at 125 MHz repetition frequency.
Manipulation of temporal localized structures in a vertical external-cavity surface-emitting laser with optical feedback
Authors: Bartolo A. , Seidel T. G. , Vigne N. , Garnache A. , Beaudoin G. , Sagnes I. , Giudici M. , Javaloyes J. , Gurevich S. V. , Marconi M.
Published: January 2021

We analyze the effect of optical feedback on the dynamics of an external-cavity passively mode-locked surface-emitting laser operating in the regime of temporal localized structures. Depending on the ratio between the cavity round trip time and the feedback delay, we show experimentally that feedback acts as a solution selector that either reinforces or hinders the appearance of one of the multistable harmonic arrangements of pulses. Our theoretical analysis reproduces well the experiment and allows us to evidence asymmetrical resonance tongues due to the parity symmetry-breaking induced by gain depletion.
Nonlinear calibration of frequency modulated continuous wave LIDAR based on a microresonator soliton comb
Authors: Jia Linhua , Wang Yang , Wang Xinyu , Zhang Fumin , Wang Weiqiang , Wang Jindong , Zheng Jihui , Chen Jiawei , Song Mingyu , Ma Xin , Yuan Meiyan , Little Brent , Chu Sai Tek , Cheng Dong , Qu Xinghua , Zhao Wei , Zhang Wenfu
Published: January 2021

Traditional frequency modulated continuous wave (FMCW) LIDAR ranging is based on heterodyne detection, calculating unknown distance by extracting the frequency of the interference signal, while the main error source is frequency modulation (FM) nonlinearity. In this paper, a ranging system based on a microresonator soliton comb is demonstrated to correct the nonlinearity by sampling the ranging signals at equal frequency intervals, producing a ranging error lower than 20 µm, while at the range of 2 m. Advantages of fast data acquisition, light computation requirements, and a simple optical path, without long optical fiber, give this method a high practical value in precision manufacturing.
Bistability of optical harmonic generation in monolayer graphene plasmonics
Authors: Li Xin , Tan Yunfeng , Yin Luying , Huo Yanyan , Zhao Lina , Yue Qingyang , Ning Tingyin
Published: January 2021

We report the bistability of second- and third-harmonic generation in monolayer graphene plasmonics supported by graphene nanoribbon arrays. The nonlinear optical bistability of harmonic generation at the ultra-low threshold intensity

∼

100

k
W

/

c
m

2

, along with the traditional linear optical bistability of transmittance, is observed due to the different local fundamental fields at the lower and higher state when the Kerr effect of graphene is considered. Importantly, the working fundamental wavelength can be tuned by the Fermi level of graphene and geometrical structure, which leads to the linear and nonlinear optical bistability available in a broadband for potential applications in advanced all-optical devices.
Active probing to highlight approaching transitions to ictal states in coupled neural mass models
Authors: Carvalho Vinícius Rezende , Moraes Márcio Flávio Dutra , Cash Sydney S. , Mendes Eduardo Mazoni Andrade Marçal
Published: January 2021

The extraction of electrophysiological features that reliably forecast the occurrence of seizures is one of the most challenging goals in epilepsy research. Among possible approaches to tackle this problem is the use of active probing paradigms in which responses to stimuli are used to detect underlying system changes leading up to seizures. This work evaluates the theoretical and mechanistic underpinnings of this strategy using two coupled populations of the well-studied Wendling neural mass model. Different model settings are evaluated, shifting parameters (excitability, slow inhibition, or inter-population coupling gains) from normal towards ictal states while probing stimuli are applied every 2 seconds to the input of either one or both populations. The correlation between the extracted features and the ictogenic parameter shifting indicates if the impending transition to the ictal state may be identified in advance. Results show that not only can the response to the probing stimuli forecast seizures but this is true regardless of the altered ictogenic parameter. That is, similar feature changes are highlighted by probing stimuli responses in advance of the seizure including: increased response variance and lag-1 autocorrelation, decreased skewness, and increased mutual information between the outputs of both model subsets. These changes were mostly restricted to the stimulated population, showing a local effect of this perturbational approach. The transition latencies from normal activity to sustained discharges of spikes were not affected, suggesting that stimuli had no pro-ictal effects. However, stimuli were found to elicit interictal-like spikes just before the transition to the ictal state. Furthermore, the observed feature changes highlighted by probing the neuronal populations may reflect the phenomenon of critical slowing down, where increased recovery times from perturbations may signal the loss of a systems’ resilience and are common hallmarks of an impending critical transition. These results provide more evidence that active probing approaches highlight information about underlying system changes involved in ictogenesis and may be able to play a role in assisting seizure forecasting methods which can be incorporated into early-warning systems that ultimately enable closing the loop for targeted seizure-controlling interventions.
Polygenic adaptation of rosette growth in Arabidopsis thaliana
Authors: Wieters Benedict , Steige Kim A. , He Fei , Koch Evan M. , Ramos-Onsins Sebastián E. , Gu Hongya , Guo Ya-Long , Sunyaev Shamil , de Meaux Juliette
Published: January 2021

The rate at which plants grow is a major functional trait in plant ecology. However, little is known about its evolution in natural populations. Here, we investigate evolutionary and environmental factors shaping variation in the growth rate of Arabidopsis thaliana. We used plant diameter as a proxy to monitor plant growth over time in environments that mimicked latitudinal differences in the intensity of natural light radiation, across a set of 278 genotypes sampled within four broad regions, including an outgroup set of genotypes from China. A field experiment conducted under natural conditions confirmed the ecological relevance of the observed variation. All genotypes markedly expanded their rosette diameter when the light supply was decreased, demonstrating that environmental plasticity is a predominant source of variation to adapt plant size to prevailing light conditions. Yet, we detected significant levels of genetic variation both in growth rate and growth plasticity. Genome-wide association studies revealed that only 2 single nucleotide polymorphisms associate with genetic variation for growth above Bonferroni confidence levels. However, marginally associated variants were significantly enriched among genes with an annotated role in growth and stress reactions. Polygenic scores computed from marginally associated variants confirmed the polygenic basis of growth variation. For both light regimes, phenotypic divergence between the most distantly related population (China) and the various regions in Europe is smaller than the variation observed within Europe, indicating that the evolution of growth rate is likely to be constrained by stabilizing selection. We observed that Spanish genotypes, however, reach a significantly larger size than Northern European genotypes. Tests of adaptive divergence and analysis of the individual burden of deleterious mutations reveal that adaptive processes have played a more important role in shaping regional differences in rosette growth than maladaptive evolution.
Natural variations of TFIIAγ gene and LOB1 promoter contribute to citrus canker disease resistance in Atalantia buxifolia
Authors: Tang Xiaomei , Wang Xia , Huang Yue , Ma Ling , Jiang Xiaolin , Rao Muhammad Junaid , Xu Yuantao , Yin Ping , Yuan Meng , Deng Xiuxin , Xu Qiang
Published: January 2021

Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is one of the most devastating diseases in citrus industry worldwide. Most citrus cultivars such as sweet orange are susceptible to canker disease. Here, we utilized wild citrus to identify canker-resistant germplasms, and found that Atalantia buxifolia, a primitive (distant-wild) citrus, exhibited remarkable resistance to canker disease. Although the susceptibility gene LATERAL ORGAN BOUNDARIES 1 (LOB1) could also be induced in Atalantia after canker infection, the induction extent was far lower than that in sweet orange. In addition, three of amino acids encoded by transcription factor TFIIAγ in Atalantia (AbTFIIAγ) exhibited difference from those in sweet orange (CsTFIIAγ) which could stabilize the interaction between effector PthA4 and effector binding element (EBE) of LOB1 promoter. The mutation of AbTFIIAγ did not change its interaction with transcription factor binding motifs (TFBs). However, the AbTFIIAγ could hardly support the LOB1 expression induced by the PthA4. In addition, the activity of AbLOB1 promoter was significantly lower than that of CsLOB1 under the induction by PthA4. Our results demonstrate that natural variations of AbTFIIAγ and effector binding element (EBE) in the AbLOB1 promoter are crucial for the canker disease resistance of Atalantia. The natural mutations of AbTFIIAγ gene and AbLOB1 promoter in Atalantia provide candidate targets for improving the resistance to citrus canker disease.
Modal properties of fruit-rachilla system of the macaw palm
Authors: Villar Flora Maria de Melo , Pinto Francisco de Assis de Carvalho , Santos Fabio Lucio , Queiroz Daniel Marçal de , Pereira Mariana Ribeiro , Magalhães Valente Domingos Sárvio
Published: January 2021

The macaw palm has been domesticated due to its potential use in the production of biofuel, in addition to several co-products that can be generated from its oil and pulp. One of the current challenges in this area is the harvesting, as there are no specific machines for this operation. Therefore, it is necessary to determine the appropriate information regarding the physical properties of the plant, so that it is feasible to develop the technologies necessary for the commercial scale application of macaw palm, allowing it to contribute to the sustainable production of raw material for the biofuel industry and other co-products. The principle of mechanical vibration can be used to shed fruit from trees when ripe, and it can be a method used for harvesting. Thus, as proposed in this study, it was necessary to study the dynamic behavior of the fruit-rachilla system during vibration. Hence, the modal properties of the system were determined. A study on the dynamic behaviors was carried out using a deterministic finite element model, and the natural frequencies were obtained through a frequency-scanning test to evaluate the model. The mean relative error (MRE) between the measured and simulated natural frequencies was also used to evaluate the model. The natural frequencies, determined experimentally, varied from 26.21 to 33.45 Hz on average, whereas the simulated frequencies varied from 24.81 to 39.27 Hz. The overall MRE was 9.08%. Once the model was validated, a sensibility test was carried out, which showed that the density of fruit and the elasticity modulus are the parameters that most influence the natural frequencies of the fruit-rachilla system.
Amianthoid transformation of costal cartilage matrix in children with pectus excavatum and pectus carinatum
Authors: Kurkov Alexandr , Guller Anna , Fayzullin Alexey , Fayzullinа Nafisa , Plyakin Vladimir , Kotova Svetlana , Timashev Petr , Frolova Anastasia , Kurtak Nikita , Paukov Vyacheslav , Shekhter Anatoly
Published: January 2021

Background

It is unclear if amianthoid transformation (AT) of costal cartilage extracellular matrix (ECM) has an impact on the development of pectus excavatum (PE) and pectus carinatum (PC).

Methods

AT foci were examined in intrasurgical biopsy specimens of costal cartilages of children (8–17 years old) with PE (n = 12) and PC (n = 12) and in age-matching autopsy control samples (n = 10) using histological and immunohistochemical staining, atomic force and nonlinear optical microscopy, transmission and scanning electron microscopy, morphometry and statistics.

Results

AT areas were identified in the costal cartilage ECM in children with normal chest, PE and PC. Each type of the AT areas (“canonical”, “intertwined”, “fine-fibred” and “intralacunary”) had a unique morphological pattern of thickness and alignment of amianthoid fibers (AFs). AFs were formed via lateral aggregation of collagen type II fibrils in the intact ECM. Foci of the AT were observed significantly more frequently in the PE and PC groups. The AT areas had unique quantitative features in each study group.

Conclusion

AT is a structurally diverse form of ECM alteration present in healthy and pathological costal cartilage. PE and PC are associated with specific AT disorders.
Cortical hemodynamic mapping of subthalamic nucleus deep brain stimulation in Parkinsonian patients, using high-density functional near-infrared spectroscopy
Authors: Mahmoudzadeh Mahdi , Wallois Fabrice , Tir Mélissa , Krystkowiak Pierre , Lefranc Michel
Published: January 2021

Subthalamic nucleus deep brain stimulation (STN-DBS) is an effective treatment for idiopathic Parkinson’s disease. Despite recent progress, the mechanisms responsible for the technique’s effectiveness have yet to be fully elucidated. The purpose of the present study was to gain new insights into the interactions between STN-DBS and cortical network activity. We therefore combined high-resolution functional near-infrared spectroscopy with low-resolution electroencephalography in seven Parkinsonian patients on STN-DBS, and measured cortical haemodynamic changes at rest and during hand movement in the presence and absence of stimulation (the ON-stim and OFF-stim conditions, respectively) in the off-drug condition. The relative changes in oxyhaemoglobin [HbO], deoxyhaemoglobin [HbR], and total haemoglobin [HbT] levels were analyzed continuously. At rest, the [HbO], [HbR], and [HbT] over the bilateral sensorimotor (SM), premotor (PM) and dorsolateral prefrontal (DLPF) cortices decreased steadily throughout the duration of stimulation, relative to the OFF-stim condition. During hand movement in the OFF-stim condition, [HbO] increased and [HbR] decreased concomitantly over the contralateral SM cortex (as a result of neurovascular coupling), and [HbO], [HbR], and [HbT] increased concomitantly in the dorsolateral prefrontal cortex (DLPFC)—suggesting an increase in blood volume in this brain area. During hand movement with STN-DBS, the increase in [HbO] was over the contralateral SM and PM cortices was significantly lower than in the OFF-stim condition, as was the decrease in [HbO] and [HbT] in the DLPFC. Our results indicate that STN-DBS is associated with a reduction in blood volume over the SM, PM and DLPF cortices, regardless of whether or not the patient is performing a task. This particular effect on cortical networks might explain not only STN-DBS’s clinical effectiveness but also some of the associated adverse effects.
Gαi1 inhibition mechanism of ATP-bound adenylyl cyclase type 5
Authors: Narzi Daniele , van Keulen Siri C. , Röthlisberger Ursula
Published: January 2021

Conversion of adenosine triphosphate (ATP) to the second messenger cyclic adenosine monophosphate (cAMP) is an essential reaction mechanism that takes place in eukaryotes, triggering a variety of signal transduction pathways. ATP conversion is catalyzed by the enzyme adenylyl cyclase (AC), which can be regulated by binding inhibitory, Gαi, and stimulatory, Gαs subunits. In the past twenty years, several crystal structures of AC in isolated form and complexed to Gαs subunits have been resolved. Nevertheless, the molecular basis of the inhibition mechanism of AC, induced by Gαi, is still far from being fully understood. Here, classical molecular dynamics simulations of the isolated holo AC protein type 5 and the holo binary complex AC5:Gαi have been analyzed to investigate the conformational impact of Gαi association on ATP-bound AC5. The results show that Gαi appears to inhibit the activity of AC5 by preventing the formation of a reactive ATP conformation.
Why are self-medication opportunities limited in Austria? An interview study and comparison with other countries
Authors: Gauld Natalie J. , Baumgärtel Christoph A. , Buetow Stephen A.
Published: January 2021

Background

Austria has high health resource use compared to similar countries. Reclassifying (switching) medicines from prescription to non-prescription can reduce pressure on health resources and aid timely access to medicines. Since Austria is less progressive in this area than many other countries, this research aimed to elucidate enablers and barriers to it reclassifying medicines and make recommendations for change in the context of similar research conducted elsewhere.

Methods

Qualitative research using a heuristic approach was conducted in Austria in 2018. Informed by their own “insider” and “outsider” knowledge, the authors identified themes from personal interviews with 24 participants, including reclassification committee members, government officials and stakeholders, before comparing these themes with earlier research findings.

Results

Significant barriers to reclassification included committee conservatism, minimal political support, medical negativity and few company applications. Insufficient transparency about committee decisions, expectations of adverse committee decisions and a limited market discouraged company applications. Austria’s ‘social partnership’ arrangement and consensus decision making aided a conservative approach, but the regulator and an alternative non-committee switch process were enabling. Pharmacy showed mixed interest in reclassification. Suggested improvements include increasing transparency, committee composition changes, encouraging a more evidence-based approach by the committee, more pharmacy undergraduate clinical training, and companies using scientific advisory meetings and submitting high quality applications.

Conclusion

Removing barriers to reclassification would facilitate non-prescription availability of medicines and encourage self-care, and could reduce pressure on healthcare resources.
Knowledge of COVID-19 and preventive behaviors among waiters working in food and drinking establishments in Southwest Ethiopia
Authors: Qanche Qaro , Asefa Adane , Nigussie Tadesse , Hailemariam Shewangizaw , Duguma Tadesse
Published: January 2021

Background

Waiters working in different food and drinking establishments have a higher risk of contracting COVID-19 and transmitting the infection to others because they interact with many people. Most COVID-19 related studies in Ethiopia mainly focused on the general population, whereas, this study aimed to assess the knowledge of COVID-19 and preventive behaviors among waiters in Southwest Ethiopia.

Methods

A cross-sectional study was conducted from June 1 to June 15, 2020, among waiters working in food and drinking establishments found in Mizan-Aman, Jemu, and Masha towns in Southwest Ethiopia. A total of 422 waiters were selected using a simple random sampling technique, and the data were collected through face-to-face interviews using a structured questionnaire. The data were entered into Epi-data manager version 4.0.2 and analyzed using SPSS version 22. Multivariable binary logistic regression analysis was carried out to identify predictors of good preventive behaviors at a p-value of less than 0.05.

Results

Four hundred and sixteen respondents participated in this study, with a response rate of 98.6%. A significant proportion of participants know the cause, route of transmission, symptoms, and prevention methods of COVID-19 virus. However, very few (21.2%) had good preventive behaviors. The study showed that good preventive behavior was positively associated with female sex (AOR = 2.33, 95% CI: 1.38–3.94), higher schooling (AOR = 0.39, 95% CI: 0.17–0.88), high-risk perception (AOR = 2.26, 95% CI: 1.51–4.32), and high perceived self-efficacy (AOR = 1.1.75, 95% CI: 1.05–2.90).

Conclusions

A significant proportion of waiters know common symptoms of COVID 19, route of transmission, and its prevention methods. However, the preventive behavior was very low. Thus, all concerned bodies working on the prevention and control of COVID-19 should give attention to this population group to enhance compliance with recommended preventive behaviors.
Judges’ evaluation reliability changes between identifiable and anonymous performance of hip-hop dance movements
Authors: Sato Nahoko , Hopper Luke S.
Published: January 2021

Hip-hop competitions are performed across the world. In the recent inclusion in the 2018 Youth Olympic Games, the assessment of hip-hop performance is undertaken by a panel of judges. The purpose of this study was to determine the reliability of different visualisation tools utilised in the assessment of the hip-hop dance movements. Ten dancers performed basic rhythmic hip-hop movements which were captured using a motion capture system and video camera. Humanoid and stick figure animations of the dancers’ movements were created from the motion capture data. Ten judges then assessed 20 dance trials through observation using three different visualisation tools on a computer display, each of which provided different representations of a given hip-hop performance: (1) the actual video of the dancers; (2) an anonymous stick figure animation; (3) an anonymous humanoid animation. Judges were not informed that they were repeating an assessment of the performances across the three visualisation tools. The humanoid animation demonstrated the highest inter-class correlation coefficients among the three methods. Despite the stick figure animation demonstrating moderate to high reliability, both the humanoid animation and the video demonstrated very high reliability in the intra-class correlation coefficient. It is recommended that further research is undertaken exploring the use of humanoid animation as a formative assessment tool in the evaluation of hip-hop dance and the evolution of hip-hop into a respected artistic athletic discipline.
Need for self-medication using over-the-counter psychoactive agents: A national survey in Japan
Authors: Shiina Akihiro , Niitsu Tomihisa , Iyo Masaomi
Published: January 2021

Self-medication using over-the-counter (OTC) drugs is an option for the autonomous treatment of several health problems. However, the use of OTC drugs to treat psychiatric conditions remains controversial. To clarify opinions regarding the use of OTC drugs to treat psychiatric problems, we conducted an anonymous online survey of 3000 people in Japan. Participants were stratified into three groups according to their history of mental health problems. Few participants had engaged in self-medication using OTC drugs for psychiatric symptoms, with the exception of insomnia. Participants who had used OTC drugs reported feeling less satisfied with their experience compared with those who had consulted a specialist. Participants who had used sleeping pills were likely to hold relatively positive opinions regarding the use of OTC psychiatric drugs. In conclusion, the need for self-medication of psychiatric symptoms appears to be limited. Education and further research may be necessary to promote self-medication for proper treatment of psychiatric conditions in Japan.
Dimensions of social and political capital in interventions to improve household well-being: Implications for coffee-growing areas in southern Colombia
Authors: Suárez Adriana E. , Gutiérrez-Montes Isabel , Ortiz-Morea Fausto Andres , Ordoñez Claudia , Suárez Juan Carlos , Casanoves Fernando
Published: January 2021

This paper studies the influence of community capitals on well-being through a Community Capital Index (CCI) within coffee-growing families in southern Colombia. Our results show different farm typologies, with different levels of capital endowment translated into well-being that, in our case, were represented in the CCI. Specifically, social and political capitals positively affect coffee-growing families’ decisions in terms of life strategies. The results of this study increase our understanding of welfare enhancement and its relationship with capital endowment according to the type of coffee producer, having implications for the planning of more effective programs towards the improvement of quality of life.