bluuebunny/crossref_metadata_2025 huggingface dataset:
Composite Logic Gate Element and Multiplexer for Optical Computing and Optical Communication
Authors: Haus J. W. , Bowden C. M. , Sung C. C.
Published: February 2023

Mirrorless (cavityless) optical bistability (OB), due to temperature-dependent renormalization of the absorption peak of the bound exciton resonance in CdS has been observed and interpreted1 in terms of coupling between the internal field intensity and the temperature in the nonlinear material. It was shown2 that the heat conductivity boundary conditions determine the conditions for bistability of a sample of the material. In fact, we showed earlier that when the boundary conditions at the ends of the sample are such that the heat resistance at the exit end HL = h1/3 where ho is the heat resistance at the entrance face, two hysteresis curves result, one clockwise with increasing input intensity at lower incident fields due to increasing absorption and the other at higher field values due to decreasing absorption which is counter-clockwise, Figures 1a and 1b.
Instabilities in Semiconductors with Induced Absorption Optical Bistability
Authors: Lindberg M. , Koch S.W. , Haug H.
Published: February 2023

Recently, we predicted1) that partial sample switching can occur in a system showing resonatorless optical bistability due to induced absorption. For an increasing intensity of the incident light, a stepwise propagation of the kink in the excitation profile takes place. In the meantime, the corresponding modulation of the transmitted light has been observed in sharp-cut color filters2). Here, we present an in-depth study of the structure, formation and motion of the kinks. We supplement and expand our original numerical investigations1) by detailed analytical studies. We show that the kink profile may be approximated by a soliton structure if the diffusion of the excitation density is taken into account. Furthermore, we present some simple estimates for the kink propagation.
Measurement of Dimension of Chaos in Optical Bistability
Authors: Derstine M.W. , Hopf F.A. , Kaplan D.L. , Rose M.H.
Published: February 2023

Our experimental setup consists of a helium-neon laser whose beam passes through a modulator consisting of a Gian prism polarizer and a KDP crystal. The beam passes through the crystal four times before coming back through the polarizer where it is coupled into an optical fiber. The light emerging from the fiber is detected with a photomultiplier, and an amplified electrical signal is applied to the KDP crystal thereby achieving a negative feedback. Prior to amplification, the electrical signal is sampled six times per round trip time using a transient digitizer and stored on a computer.
Characterization of a strange attractor in an optical system
Authors: Tredicce J. R. , Arecchi F.T. , Gadomski W. , Poggi A. , Puccioni G. P.
Published: February 2023

By using an embedding technique [1] in both time series and stroboscopic sections of the output intensity of a CO2 laser with modulated losses [2], we perform dimensionality tests on periodic and aperiodic attractors. Measurements at the accumulation point of the Feigenbaum cascade and inside the chaotic region (Fig. 1) confirms previous results of the general theory on non-linear dynamics.
Nonlinear Optical Properties of Semiconductor-Doped Glasses
Authors: Jain R. K.
Published: February 2023

We review recent work on the linear and nonlinear optical properties of semiconductor-doped glasses: (1) the origin and speed of the large Kerr-type nonlinearity found therein, and (2) reported discrepancies/anomalies in the optical characteristics and in the picosecond/subpicosecond dynamics of band-edge excitation.
Theory of Nonlinear Waveguides: Stationary and Propagating Waves
Authors: Moloney J.V.
Published: February 2023

Theoretical techniques for enumerating stationary TE and TM nonlinear guided (NGW) and nonlinear surface (NSW) wave solutions for various permutations of nonlinear dielectric layered geometries will be overviewed. Emphasis will be placed on discussing the stability of such stationary waves to propagation along the guiding structure. It will be shown that these nonlinear waves represent a small subclass of special solutions to a much more general propagation problem whose solutions are related to spatial soliton/solitary wave solutions of a modified nonlinear Schrödinger equation. Most stability studies, with one important exception [1], have involved direct numerical integration of this modified NLS equation using the appropriate nonlinear stationary wave solution as initial data. The analytic stability technique [1] will be illustrated for a variety of nonlinear optical dielectric responses. Recent developements in the study of diffusion effects and instabilities in the 3D problem will also be discussed. The discussion will be confined mainly to layered linear/nonlinear dielectric media with positive (self-focussing) nonlinear optical responses.
Spatio-Temporal Instabilities in a Saturable Homogeneously Broadened Ring Cavity
Authors: Le Berre M. , Ressayre E. , Tallet A. , Zondy J.J.
Published: February 2023

The plane-wave saturable homogeneously broadened ring cavity displays rich sequences of bifurcations and high-dimensional chaos when the atomic radiative lifetime ɤ–1 is of order of magnitude or shorter than the round-trip time of the light through the cavity, τR. This delayed-feedback system exhibits low-dimensional bifurcations (periodic and quasi-periodic oscillations, intermittencies) as already analyzed and observed in ordinary nonlinear systems.
Steady-State and Time-Resolved Excitonic Optical Nonlinearities in MBE-Grown ZnSe
Authors: Park S.H. , Fluegel B.D. , Morgan R. , Joffre M. , Sokoloff J. , Koch S.W. , Peyghambarian N. , Potts J.E. , Cheng H.
Published: February 2023

ZnSe and ZnS are known to have a thermal nonlinearity. This has been used in the past for demonstrating optical bistability1,2,3, however the thermal nature of the nonlinearity makes these switches inherently slow and inefficient. Here we have measured the nonlinear spectra and decay times for a large, fast, electronic nonlinearity in MBE-grown thin films of ZnSe. These samples were grown on GaAs substrates which were then removed by chemical etching.
Subnanosecond absorptive switching in GaAs etalons
Authors: Sahlén Olof , Olin Ulf , Landgren Gunnar , Rask Michael
Published: February 2023

Optical bistability and external beam switching at wavelengths equal to or longer than the bandgap wavelength in GaAs have been extensively studied, Refs 1-4.
Scaling of Optical Logic Devices and Arrays
Authors: Jewell J. L. , McCall S. L. , Lee Y. H. , Scherer A. , Gossard A. C. , English J. H.
Published: February 2023

The use of ion-beam-assisted etching to form ~ 1.5-µm diameter waveguiding "posts", or microresonators, in a GaAs/AlAs Fabry-Perot structure grown entirely by molecular beam epitaxy has reduced the device cross-sectional areas, energy requirements and recovery times all by more than an order of magnitude1. Prior to etching the minimum controlling energy required for an optical logic etalon operation2 was 20 pJ. The device diameter, defined as the illuminated region, was about 10 µm and recovery time was estimated to be several ns, both inferred from measurements on comparable devices. For 1.5-µm microresonators the energy is 0.6 pJ and recovery time, ~ 200 ps (Fig. 1). Thus, at least over this size range, the energy and time requirements scale directly with cross-sectional area. It is likely that this scaling will continue down to λ/n diameters, i.e. to 1/4 µm for GaAs, or another factor 36 in area. This would reduce controlling energies to ~ 17 fJ and recovery times to ~ 6 ps for the same Fabry-Perot design. The energies (but not recovery times) should be much further reduced by use of thinner, higher-finesse etalons, and much further still by use of excitonic nonlinearities which are not cancelled out by bandgap renormalization. The latter might be obtained from sufficiently-high-quality quantum confining semiconductors or operation at reduced temperatures. With all these improvements, controlling energies should approach the statistical limit of a few hundred photons3,4.
Operation Characteristics of Pixellated Nonlinear Interference Filters
Authors: Abraham E. , Godsalve C. , Wherrett B.S.
Published: February 2023

We present static and dynamic theoretical studies of the effects of material pixellation on the operating characteristics of bistable elements using nonlinear interference filters. These devices are based on a refractive thermal nonlinearity.
Numerical Analysis of Electro-Optic Effects in Superlattices Comparison with Photoreflectance Results
Authors: Cavaillès J.A. , Erman M. , Frijlink P.
Published: February 2023

Due to their possible applications in opto-electronic devices, Electric Field Effects on optical properties of isolated quantum wells have been extensively studied both experimentally and theoretically [1, 2]. By contrast very few theoretical studies have been reported about these effects on coupled Multiple Quantum Well systems [3,4] none of which, to our knowledge, showing comparison with experimental results.
Nonlinearity of Thin-Film Semiconductor Interferometers Due to Interlayer Boundary Photoemf and Electrooptic Processes
Authors: Karpushko F.V.
Published: February 2023

From the first publication /1/ and up to now /2/ the thin-film semiconductor interferometer bistable devices have been the subject of serious interest to realize the components of optical digital computers. The purpose of this report is to show that in such systems strong and fast optical nonlinearity of electron nature is possible under certain conditions.
Chaos In A CO2 Laser Containing A Saturable Absorber
Authors: Bekkali Abdelkaddous , Papoff Francesco , Dangoisse Didier , Glorieux Pierre
Published: February 2023

In addition to displaying optical bistability, the laser containing a saturable absorber (LSA) is known to present self-pulsing which was called Passive Q-Switching(PQS) .This effect appears to be due not only to a simple destabilisation of the upper branch of the bistability curve but also to the interplay of the instability points of the laser. The dynamics of this purely optical system appears to be very rich .Chaos has been experimentally observed in a CO2 laser containing CH3I or SF6 as a saturable absorber, and the transition towards chaos follows different scenarios depending on the interplay of the various instabilities present in the system. To be more specifics period-doubling cascade has been observed for small laser cavity detunings (<10 Mhz) and Shil’nikov-like dynamics have been observed for larger detunings (> 20 Mhz).. Another example of Shil'nikov dynamics in presence of several competing instabilities is given in the work of Arecchi et al on a CO2 laser with feedback (1).
Propagation and Stability Characteristics of Nonlinear Guided Waves in Saturable Nonlinear Media
Authors: Etrich C.M. , Mitchell C.S. , Moloney J.V.
Published: February 2023

We investigate the stability of analytic symmetric and asymmetric solutions for guided waves in a symmetric layered structure comprising self-focussing, self-focussing with saturation and self-defocussing. The refractive indices in the guiding, substrate and cladding layers are given by n2 = n02 and n2 = n12 + α|E|2 + β|E|4, respectively. The stability analysis by means of composite phase portrait construction seems to be in agreement with reference [1]. Instability of the symmetric waves occurs at powers where the asymmetric waves appear. Stability is restored at a second bifurcation point for β < 0 below a certain value (Fig. 1). However, testing the stability numerically via propagation of the analytic solutions, the waves become unstable at higher powers before the bifurcation point in the self-defocussing case.
Multimode Instability in Intrinsic Optical Bistability: A Quantitative Experimental Investigation
Authors: Segard Bernard , Macke Bruno
Published: February 2023

We have recently observed a sinewave self-pulsing in the beam transmitted by a passive cavity containing 2-level molecules, driven by a continuous wave. In this experiment made at a wavelength λ ≅ 3.5 mm, the intracavity Rabi frequency is comparable to the free spectral range ( 830 kHz ) of the very long cavity used (l =182 m) {1} and much larger than the collisional linewidth (≅ 25 kHz) .The medium is then strongly saturated by the driving field ( saturation parameter > 1000) so that its absorption , heavy in the linear regime (αl > 100), is in fact quite moderate. We claim that the self-pulsing observed in these conditions is the first experimental evidence of the multimode instability, predicted a long time ago by Bonifacio and Lugiato {2} but not yet observed. This instability is the multimode counterpart of the single mode instability, recently observed by Orozco et al {3}.
Lyapunov Vectors Treatment for Bifurcations in Retarded Differential Systems
Authors: Le Berre M. , Ressayre E. , Tallet A.
Published: February 2023

A method is proposed to describe bifurcations in high-dimensional problems. The saturable ring cavity driven by a retarded feedback is studied as an example of retarded differential difference device. The main stage of the treatment is the calculation of the Lyapunov separation vectors as an orthogonal basis for the system. These vectors span the unstable and stable directions of the linearized equations. They are generated by the Gram–Schmidt procedure1 which provides Lyapunov exponents arranged in decreasing order. This fortunate property allows the reduction of problems posed in infinite dimensional spaces to low dimensional ones defined by the set of Lyapunov vectors which carry the relevant information about the bifurcation.
Achieving 100 GW idler pulses from an existing petawatt optical parametric chirped pulse amplifier
Authors: Bucht S. , Roides R. G. , Webb B. , Haberberger D. , Feng C. , Froula D. H. , Bromage J.
Published: February 2023

Optical parametric chirped-pulse-amplification produces two broadband pulses, a signal and an idler, that can both provide peak powers >100 GW. In most cases the signal is used, but compressing the longer-wavelength idler opens up opportunities for experiments where the driving laser wavelength is a key parameter. This paper will describe several subsystems that were added to a petawatt class, Multi-Terawatt optical parametric amplifier line (MTW-OPAL) at the Laboratory for Laser Energetics to address two long-standing issues introduced by the use of the idler, angular dispersion, and spectral phase reversal. To the best of our knowledge, this is the first time that compensation of angular dispersion and phase reversal has been achieved in a single system and results in a 100 GW, 120-fs duration, pulse at 1170 nm.
Generation of 1.3 µm femtosecond pulses by cascaded nonlinear optical gain modulation in phosphosilicate fiber
Authors: Qi Weiao , Zhou Jiaqi , Cao Xinru , Cheng Zhi , Li Sha , Jiang Huawei , Cui Shuzhen , Feng Yan
Published: February 2023

Nonlinear optical gain modulation (NOGM) is a simple and effective approach to generate highly coherent ultrafast pulses with a flexible wavelength. In this work, we demonstrate 34 nJ, 170 fs pulse generation at 1319 nm through a piece of phosphorus-doped fiber by two-stage cascaded NOGM with a 1064 nm pulsed pump. Beyond the experiment, numerical results show that 668 nJ, 391 fs pulses at 1.3 µm can be produced with up to 67% conversion efficiency by increasing the pump pulse energy and optimizing the pump pulse duration. This would offer an efficient method to obtain high-energy sub-picosecond laser sources for applications such as multiphoton microscopy.
Realization of large transmitted Goos–Hänchen shifts with high (near 100%) transmittance based on a coupled double-layer grating system
Authors: Du Shihao , Che Zhiyuan , Zhao Maoxiong , Liu Wenzhe , Shi Lei
Published: February 2023

Achieving Goos–Hänchen shift enhancement with high transmittance or reflectance based on the resonance effect is challenging due to the drop in the resonance region. This Letter demonstrates the realization of large transmitted Goos–Hänchen shifts with high (near 100%) transmittance based on a coupled double-layer grating system. The double-layer grating is composed of two parallel and misaligned subwavelength dielectric gratings. By changing the distance and the relative dislocation between the two dielectric gratings, the coupling of the double-layer grating can be flexibly tuned. The transmittance of the double-layer grating can be close to 1 in the entire resonance angle region, and the gradient of the transmissive phase is also preserved. The Goos–Hänchen shift of the double-layer grating reaches ∼30 times the wavelength, approaching 1.3 times the radius of the beam waist, which can be observed directly.
Density field measurement deflectometry for supersonic wind tunnels
Authors: Zhang Xinwei , Li Dahai , Zhang Zekun , Huang Baolong , Wang Ruiyang , Pu Hongyu , Huang Zhenxin , Chen Zhi
Published: February 2023

A method for the quantitative measurement of two-dimensional density field distributions based on deflectometry is proposed. With this method, from the point of view of the inverse Hartmann test, the light rays emitted from the camera reach the screen after being disturbed by the shock-wave flow field. After the coordinates of the point source are obtained by using the phase information, the deflection angle of the light ray can be calculated, and then the distribution of the density field can be determined. The principle of density field measurement deflectometry (DFMD) is described in detail. In the experiment, the density fields in wedge-shaped models with three different wedge angles are measured in supersonic wind tunnels, the experimental results from the proposed method are compared with the theoretical results, and the measurement error is found to be around 2.76 × 10−3kg/m3. This method has the advantages of fast measurement, a simple device, and low cost. It provides a new approach, to the best of our knowledge, to measuring the density field of a shock-wave flow field.
Silicon metasurface-based infrared polarizing beam splitter with on-demand deflection angles
Authors: Xia Chunsheng , Ren Yongze , Lin Peicheng , Wang Yilin , Xu Ting
Published: February 2023

Polarizing beam splitters (PBSs) play an important role in applications requiring polarization multiplexing or high polarization purity. Traditional prism-based PBSs usually have large volumes, which hampers their further applications in ultracompact integrated optical systems. Here, we demonstrate a single-layer silicon metasurface-based PBS with the ability to deflect two orthogonally linearly polarized infrared light beams to on-demand angles. The metasurface consists of silicon anisotropic microstructures, which can provide different phase profiles for the two orthogonal polarization states. In experiments, two metasurfaces designed with arbitrary deflection angles for x- and y-polarized light exhibit good splitting performance at an infrared wavelength of 10 μm. We envision that this type of planar and thin PBS can be used in a series of compact thermal infrared systems.
3D printed microfluidic devices using TOPAS filament for THz spectroscopic measurements
Authors: Zwyssig Dominic , Hack Erwin , Zolliker Peter , Mavrona Elena
Published: February 2023

We present the 3D printing of microfluidic devices suitable for the THz regime using TOPAS filaments. We assessed the 3D-printed microfluidic devices with THz time-domain spectroscopy and X-ray microscopy. We compared the results of polished and unpolished windows of the 3D printed devices for studying the quality of the 3D printing in the THz and VIS regimes. Spectroscopic measurements were performed of water and lysozyme dissolved in water. We found that the results from the polished and unpolished devices were similar in the THz regime. A detailed calculation of the measurement uncertainty revealed that the dominant component of the measurement uncertainly was the gap thickness. Because of their optical and mechanical properties, we are convinced that 3D printing from TOPAS offers a cost-effective and rapid production of microfluidic devices usable in X-ray, UV, VIS, NIR, and THz regimes.
Derivation of chromophore concentrations in turbid media using the rate of change of optical attenuation with respect to wavelength
Authors: Hebden Jeremy C. , Fu Yihong , Pacis Danica M.
Published: February 2023

A spectroscopic method is investigated for estimating the concentrations of absorbers in highly scattering media using measurements of the rate of change of optical attenuation with wavelength. Such measurements are independent of absolute intensity and thus may be significantly less influenced by changes in coupling which often cause artefacts in medical applications of near-infrared spectroscopy. The method has been explored using a combination of stochastic (Monte Carlo) and analytical (diffusion-based) models and experiments on samples of turbid fluids. Results suggest that the method is highly tolerant of changes in the measurement geometry. The accuracy of the derived concentrations of absorbers can be strongly influenced by the wavelength dependence of scattering, and an ad-hoc, empirically-derived correction for this dependency has been investigated and implemented with some success.
High throughput hemogram of T cells using digital holographic microscopy and deep learning
Authors: Gupta Roopam K. , Hempler Nils , Malcolm Graeme P. A. , Dholakia Kishan , Powis Simon J.
Published: February 2023

T cells of the adaptive immune system provide effective protection to the human body against numerous pathogenic challenges. Current labelling methods of detecting these cells, such as flow cytometry or magnetic bead labelling, are time consuming and expensive. To overcome these limitations, the label-free method of digital holographic microscopy (DHM) combined with deep learning has recently been introduced which is both time and cost effective. In this study, we demonstrate the application of digital holographic microscopy with deep learning to classify the key CD4+ and CD8+ T cell subsets. We show that combining DHM of varying fields of view, with deep learning, can potentially achieve a classification throughput rate of 78,000 cells per second with an accuracy of 76.2% for these morphologically similar cells. This throughput rate is 100 times faster than the previous studies and proves to be an effective replacement for labelling methods.
A real-time machine-learning-driven control system of a deformable mirror for achieving aberration-free hard X-ray wavefronts
Authors: Rebuffi Luca , Shi Xianbo , Qiao Zhi , Highland Matthew , Frith Matthew , Wojdyla Antoine , Goldberg Kenneth , Assoufid Lahsen
Published: February 2023

A neural-network machine learning model is developed to control a bimorph adaptive mirror to achieve and preserve aberration-free coherent X-ray wavefronts at synchrotron radiation and free electron laser beamlines. The controller is trained on a mirror actuator response directly measured at a beamline with a real-time single-shot wavefront sensor, which uses a coded mask and wavelet-transform analysis. The system has been successfully tested on a bimorph deformable mirror at the 28-ID IDEA beamline of the Advanced Photon Source at Argonne National Laboratory. It achieved a response time of a few seconds and maintained desired wavefront shapes (e.g., a spherical wavefront) with sub-wavelength accuracy at 20 keV of X-ray energy. This result is significantly better than what can be obtained using a linear model of the mirror’s response. The developed system has not been tailored to a specific mirror and can be applied, in principle, to different kinds of bending mechanisms and actuators.
Ultra-low-loss multi-layer 8 × 8 microring optical switch
Authors: Li Xin , Gao Wei , Lu Liangjun , Chen Jianping , Zhou Linjie
Published: February 2023

Microring-based optical switches are promising for wavelength-selective switching with the merits of compact size and low power consumption. However, the large insertion loss, the high fabrication, and the temperature sensitivity hinder the scalability of silicon microring optical switch fabrics. In this paper, we utilize a three-dimensional (3D) microring-based optical switch element (SE) on a multi-layer Si3N4-on-SOI platform to realize high-performance large-scale optical switch fabrics. The 3D microring-based SE consists of a Si/Si3N4 waveguide overpass crossing in the bottom and the top layers, and Si3N4 dual-coupled microring resonators (MRRs) in the middle layer. The switch is calibration-free and has low insertion loss. With the 3D microring-based SEs, we implement an 8×8 crossbar optical switch fabric. As the resonance wavelengths of all SEs are well aligned, only one SE needs to be turned on in each routing path, which greatly reduces the complexity of the switch control. The optical transmission spectra show a box-like shape, with a passband width of ∼69  GHz and an average on-state loss of ∼0.37  dB. The chip has a record-low on-chip insertion loss of 0.52–2.66 dB. We also implement a non-duplicate polarization-diversity optical switch by using the bidirectional transmission characteristics of the crossbar architecture, which is highly favorable for practical applications. 100 Gb/s dual-polarization quadrature-phase-shift-keying (DP-QPSK) signal is transmitted through the switch without significant degradation. To the best of our knowledge, this is the first time that 3D MRRs have been used to build highly scalable polarization-diversity optical switch fabrics.
How climate change and climate variability affected trip distance of a commercial fishery
Authors: Chan Hing Ling
Published: February 2023

Changes in climate factors affect the distribution of various tuna species differently due to their unique physiological adaptations and preferred habitats. As the resulting spatial distributions of tunas alter in response to climate change and climate variability, the distribution of fishing effort will, in turn, be affected. This study uses a quantitative model to estimate the impacts of SST and ENSO events on trip distance of the Hawaii deep-set longline fleet between 1991 and 2020. The results show that the higher the SST of the fishing grounds of the Hawaii longline fleet, the longer trip distance; whereas ENSO events could result in shorter trip distance, possibly due to changes in catch rates of different tuna species through spatial redistribution during El Niño and La Niña events.
The identification of mediating effects using genome-based restricted maximum likelihood estimation
Authors: Rietveld Cornelius A. , de Vlaming Ronald , Slob Eric A. W.
Published: February 2023

Mediation analysis is commonly used to identify mechanisms and intermediate factors between causes and outcomes. Studies drawing on polygenic scores (PGSs) can readily employ traditional regression-based procedures to assess whether traitMmediates the relationship between the genetic component of outcomeYand outcomeYitself. However, this approach suffers from attenuation bias, as PGSs capture only a (small) part of the genetic variance of a given trait. To overcome this limitation, we developed MA-GREML: a method for Mediation Analysis using Genome-based Restricted Maximum Likelihood (GREML) estimation.

Using MA-GREML to assess mediation between genetic factors and traits comes with two main advantages. First, we circumvent the limited predictive accuracy of PGSs that regression-based mediation approaches suffer from. Second, compared to methods employing summary statistics from genome-wide association studies, the individual-level data approach of GREML allows to directly control for confounders of the association betweenMandY. In addition to typical GREML parameters (e.g., the genetic correlation), MA-GREML estimates (i) the effect ofMonY, (ii) thedirect effect(i.e., the genetic variance ofYthat is not mediated byM), and (iii) theindirect effect(i.e., the genetic variance ofYthat is mediated byM). MA-GREML also provides standard errors of these estimates and assesses the significance of the indirect effect.

We use analytical derivations and simulations to show the validity of our approach under two main assumptions,viz., thatMprecedesYand that environmental confounders of the association betweenMandYare controlled for. We conclude that MA-GREML is an appropriate tool to assess the mediating role of traitMin the relationship between the genetic component ofYand outcomeY. Using data from the US Health and Retirement Study, we provide evidence that genetic effects on Body Mass Index (BMI), cognitive functioning and self-reported health in later life run partially through educational attainment. For mental health, we do not find significant evidence for an indirect effect through educational attainment. Further analyses show that the additive genetic factors of these four outcomes do partially (cognition and mental health) and fully (BMI and self-reported health) run through an earlier realization of these traits.
Preventive dental care utilization for children with special healthcare needs including the COVID-19 pandemic, national survey of children’s health, 2020
Authors: Wiener R. Constance
Published: February 2023

It is important to determine access to preventive care among vulnerable populations. The purpose of this research is to compare preventive dental utilization between children with special healthcare needs (CSHCN) and children without special healthcare needs (CWSHCN) using National Survey of Children’s Health, 2020 (NSCH, 2020) data. A cross-sectional study design was used in this secondary data analysis of data from June 2020 to January 2021, NSCH, 2020, a publicly available data set with demographic and healthcare information. Parents/guardians responded to validated questions including one asking them to recall preventive dental services received during the previous year (June 2019 to January 2021). This was a critical time of transition from normal, pre-pandemic activities (June 2019 to March 2020) to the pandemic period (March 2020 to January 2021) with restrictions and no available vaccinations for children. Data analyses for the NSCH, 2020 data included frequency determinations, Chi Square analyses by preventive dental visit, and logistic regression analyses. There were 40,140 children in the sample, and 20.6% were CSHCN. Overall, 75.0% of children received a dental preventive visit. This study had an interaction of CSHCN status and medical visits within the previous year in which having had a medical visit was associated with CSHCN status also having a dental visit; while the CSHCN who did not have a medical visit were less likely to have a dental visit in unadjusted analysis. However, the pattern for CSHCN and the medical visit reversed in adjusted analysis. In adjusted analysis, CWSHCN and a medical visit were the most likely to also have a dental visit during this period. Many factors influenced access to preventive dental care in the months leading up to and including the COVID-19 pandemic. CSHCN with or without a medical visit were less likely to have preventive dental care than CWSHCN with a medical visit in logistic regression analysis adjusted for sex, race/ethnicity, age, smoking in the household, medical visits within the year, insurance coverage, and highest level of education in the household.
Artificial diet alters activity and rest patterns in the olive fruit fly
Authors: Terzidou Anastasia M. , Koveos Dimitrios S. , Papadopoulos Nikos T. , Carey James R. , Kouloussis Nikos A.
Published: February 2023

Olive fruit flies,Bactrocera oleae(Diptera: Tephritidae) reared in the laboratory on an artificial diet are essential for the genetic control techniques against this pest. However, the colony’s laboratory adaptation can affect the quality of the reared flies. We used the Locomotor Activity Monitor to track the activity and rest patterns of adult olive fruit flies reared as immatures in olives (F2-F3 generation) and in artificial diet (>300 generations). Counts of beam breaks caused by the adult fly activity were used as an estimation of its locomotor activity levels during the light and dark period. Bouts of inactivity with duration longer than five minutes were considered a rest episode. Locomotor activity and rest parameters were found to be dependent on sex, mating status and rearing history. In virgin flies reared on olives, males were more active than females and increased their locomotor activity towards the end of the light period. Mating decreased the locomotor activity levels of males, but not of female olive-reared flies. Laboratory flies reared on artificial diet had lower locomotor activity levels during the light period and more rest episodes of shorter duration during the dark period compared to flies reared on olives. We describe the diurnal locomotor activity patterns ofB.oleaeadults reared on olive fruit and on artificial diet. We discuss how locomotor activity and rest pattern differences may affect the laboratory flies’ ability to compete with wild males in the field.
Frequency and types of alternative breeding strategies employed by nesting American black ducks in North Carolina
Authors: Lavretsky Philip , Hoyt Amanda , Musni Vergie M. , Howell Doug , Williams Christopher K.
Published: February 2023

Although most birds are considered to be at least partially monogamous, molecular evidence continues to uncover that many species can have multiple sexual mates. Many species of Waterfowl (Order Anseriformes) consistently deploy alternative breeding strategies, and although cavity nesting species have been well studied, few attempts to understand rates of alternative breeding strategies exist in the Anatini tribe. Here, we assay mitochondrial DNA and thousands of nuclear markers across 20 broods of American black ducks (Anas rubripes; “black duck”) that included 19 females and 172 offspring to study population structure as well as types and rates of secondary breeding strategies in coastal North Carolina. First, we report high levels of relatedness among nesting black ducks and offspring and while 17 (of 19) females were of pure black duck descent, three were found to be black duck x mallard (A.platyrhynchos) hybrids. Next, we evaluated for mismatched mitochondrial DNA and paternity identities across each female’s clutch to determine types and frequency of alternative or secondary breeding strategies. Although we report that nest parasitism occurred in two nests, 37% (7 of 19) of the sampled nests were multi-paternal as a result of extra-pair copulation. In addition to being part of a mix of strategies used to increase fecundity by successfully breeding females, we posit nest densities providing easier alternative mate access for males also explains high rates of extra-pair copulation among our sampled black ducks. Ultimately, however, while some proportion of females of many species engage in forms of secondary breeding strategies, we conclude that the decision to do so appears to be seasonally flexible for each individual.
Maternal prenatal screening programs that predict trisomy 21, trisomy 18, and neural tube defects in offspring
Authors: Chen Yiming , Ning Wenwen , Shi Yezhen , Chen Yijie , Zhang Wen , Li Liyao , Wang Xiaoying
Published: February 2023

Objective

To determine the efficacy of three different maternal screening programs (first-trimester screening [FTS], individual second-trimester screening [ISTS], and first- and second-trimester combined screening [FSTCS]) in predicting offspring with trisomy 21, trisomy 18, and neural tube defects (NTDs).

Methods

A retrospective cohort involving 108,118 pregnant women who received prenatal screening tests during the first (9–13+6 weeks) and second trimester (15–20+6 weeks) in Hangzhou, China from January–December 2019, as follows: FTS, 72,096; ISTS, 36,022; and FSTCS, 67,631 gravidas.

Result

The high and intermediate risk positivity rates for trisomy 21 screening with FSTCS (2.40% and 5.57%) were lower than ISTS (9.02% and 16.14%) and FTS (2.71% and 7.19%); there were statistically significant differences in the positivity rates among the screening programs (all P < 0.05). Detection of trisomy 21 was as follows: ISTS, 68.75%; FSTCS, 63.64%; and FTS, 48.57%. Detection of trisomy 18 was as follows; FTS and FSTCS, 66.67%; and ISTS, 60.00%. There were no statistical differences in the detection rates for trisomy 21 and 18 among the 3 screening programs (all P > 0.05). The positive predictive values (PPVs) for trisomy 21 and 18 were highest with FTS, while the false positive rate (FPR) was lowest with FSTCS.

Conclusion

FSTCS was superior to FTS and ISTS screening and substantially reduced the number of high risk pregnancies for trisomy 21 and 18; however, FSTCS was not significantly different in detecting fetal trisomy 21 and 18 and other confirmed cases with chromosomal abnormalities.
Effect of MBSR, DBT and CBT on the hypertension patients with depression/anxiety: Protocol of a systematic review and Bayesian network meta-analysis
Authors: Zhang Yan , Zhang Hailiang , Zhang Yong , Yang Zijiao , Wang Lingling , Pan Weimin , Dai Runjing , Ju Qianqian , Ren Dong , Bao Shisan , Fan Jingchun
Published: February 2023

Introduction

Hypertension, one of the most common chronic diseases worldwide, usually requires lifetime managing blood pressure (BP) with medications. Due to quite large number of hypertension patients co-exist with depression and/or anxiety, and non-cooperated with medical instruction, consequently management of BP is impaired with serious complications, resulting in compromised quality of life. Consequently quality of life of such patients is impaired with serious complications. Therefore, management of depression and/or anxiety is equally important as the treatment of hypertension. Depression and/or anxiety are independent risk factors of hypertension, which is supported by the finding that there is close correlation between hypertension are depression/or anxiety. Psychotherapy (non-drug treatment) maybe useful for hypertensive patients with depression and/or anxiety to improve their negative emotions. We aim to quantify the effective of psychological therapies in the management of hypertension patients with depression or anxiety, by comparing and ranking a network meta-analysis (NMA).

Materials and methods

Literature search for randomized controlled trials (RCTs) will be performed in five electronic databases from inception to December 2021, including PubMed, the Cochrane library, Embase, Web of Science, and China Biology Medicine disc (CBM). The search terms mainly include “hypertension”, “mindfulness-based stress reduction” (MBSR), “cognitive behavioral therapy” (CBT) and “dialectical behavior therapy” (DBT). Cochrane Collaboration quality assessment tool will be used for the risk of bias assessment. A Bayesian network meta-analysis will be performed, using WinBUGS 1.4.3, and Stata 14 will be applied to draw the network diagram, while RevMan 5.3.5 will be used to produce funnel plot for assessing the risk of publication bias. Recommended rating, development and grade methodology will also be utilized to assess the quality of evidence.

Results

Effect of MBSR, CBT and DBT will be evaluated by traditional meta-analysis directly and Bayesian network meta-analysis indirectly. Our study will provide the evidence on the efficacy and safety of psychological treatments in the hypertension patients with anxiety. There is no research ethical requirement because this is a systematic review of published literature. The results of this study will be published in a peer-reviewed journal.

Trial registration

Prospero registration number: CRD42021248566.
Antisense-acting riboswitches: A poorly characterized yet important model of transcriptional regulation in prokaryotic organisms
Authors: Serrano-Gutiérrez Mariela , Merino Enrique
Published: February 2023

Riboswitches are RNA elements involved in regulating genes that participate in the biosynthesis or transport of essential metabolites. They are characterized by their ability to recognize their target molecules with high affinity and specificity. Riboswitches are commonly cotranscribed with their target genes and are located at the 5’ end of their transcriptional units. To date, only two exceptional cases of riboswitches being situated at the 3’ end and transcribing in the antisense direction of their regulated genes have been described. The first case involves a SAM riboswitch located at the 3’ end of the ubiG-mccB-mccA operon in Clostridium acetobutylicum involved in converting methionine to cysteine. The second case concerns a Cobalamin riboswitch in Listeria monocytogenes that regulates the transcription factor PocR related to this organism’s pathogenic process. In almost a decade since the first descriptions of antisense-acting riboswitches, no new examples have been described. In this work, we performed a computational analysis to identify new examples of antisense-acting riboswitches. We found 292 cases in which, according to the available information, we infer that the expected regulation of the riboswitch is consistent with the signaling molecule it senses and the metabolic function of the regulated gene. The metabolic implications of this novel type of regulation are thoroughly discussed.
Use of participatory action research to support Syrian refugee mothers in the resettlement period in Canada: A longitudinal study
Authors: O’Mahony Joyce , Kassam Shahin , Clark Nancy , Asbjoern Trichia
Published: February 2023

Research has shown that refugees in a foreign country often experience physical and mental health challenges upon resettlement (Ahmad et al., 2021; Salam et al., 2022). In Canada, refugee women experience a range of physical and mental barriers, including poor access to interpreter services and transportation, and a lack of accessible childcare, all of which can negatively affect their successful integration (Stirling Cameron et al., 2022). Social factors that support Syrian refugees to settle successfully in Canada have been unexplored systematically. This study examines these factors from the perspectives of Syrian refugee mothers living in the province of British Columbia (BC). Framed by principles of intersectionality and community-based participatory action research (PAR), the study draws on Syrian mothers’ perspectives of social support in early, middle, and later phases of resettlement. A qualitative longitudinal design consisting of a sociodemographic survey, personal diaries, and in-depth interviews was used to gather information. Descriptive data were coded, and theme categories were assigned. Six themes emerged from data analysis: (1) Steps in the Migration Journey; (2) Pathways to Integrated Care; (3) Social Determinants of Refugee Health; (4) COVID-19 Pandemic Impacts and Ongoing Resettlement; (5) Strength-Based Capabilities of Syrian mothers; (6) Peer Research Assistant’s Research (PRAs) Experience. Results from themes 5 and 6 are published separately. Data obtained in this study contribute to the development of support services that are culturally appropriate and accessible to refugee women living in BC. Our objectives are to promote the mental health and improve the quality of life of this female population, and to enable it to access healthcare services and resources in a timely manner.
The impact of higher levels of autistic traits on risk of hikikomori (pathological social withdrawal) in young adults
Authors: Brosnan Mark , Gavin Jeff
Published: February 2023

Background

Hikikomori is an extreme state of social withdrawal, originally identified in Japan but more recently recognised internationally. Many countries imposed restrictions during the COVID-19 pandemic which may have had a detrimental impact on those at risk of hikikomori, specifically young adults and those with high levels of autistic traits.

Aims

To explore whether levels of autistic traits mediate the relationship between psychological wellbeing and hikikomori risk. We also looked at whether autistic traits mediated between lockdown experiences (e.g. not leaving the house) and hikikomori risk.

Methods

646 young people (aged 16–24) from a wide range of countries completed an online questionnaire assessing psychological wellbeing, autistic traits and experiences of lockdown for this cross-sectional study.

Results

Autistic traits mediated the relationship between both psychological wellbeing and hikikomori risk, as well as frequency of leaving the house during lockdown and hikikomori risk. Greater hikikomori risk was associated with poor psychological wellbeing, higher autistic traits and leaving the house less frequently during the COVID-19 pandemic.

Conclusions

These findings suggest similarities with Japanese hikikomori research and are consistent with suggestions that psychological wellbeing and COVID-19 restrictions are associated with increased hikikomori risk in young adults, and both associations are mediated by higher levels of autistic traits.
Passion fruit plants alter the soil microbial community with continuous cropping and improve plant disease resistance by recruiting beneficial microorganisms
Authors: Wang Ye , Teng Yao , Zhang Jianli , Zhang Zixiong , Wang Chen , Wu Xiukun , Long Xiuqin
Published: February 2023

Passion fruit (Passiflora edulis) is widely grown in tropical and subtropical regions, showing high economic and ornamental value. Microorganisms are indicators for the stability and health of the soil ecosystem, which can affect the yield and quality of passion fruit under continuous cropping. High-throughput sequencing and interactive analysis were used to analyse the variation of microbial communities in the noncultivated soil (NCS), cultivated soil (CS), and the rhizosphere soil of purple passion fruit (Passiflora edulis f. edulis ×Passiflora edulis f. flavicarpa, RP) and yellow passion fruit (Passiflora edulis f. flavicarpa, RY). An average of 98,001 high-quality fungal internal transcribed spacer (ITS) sequences, mainly from Ascomycota, Basidiomycota, Mortierellomycota, Mucoromycota and Glomeromycota, as well as an average of 71,299 high-quality bacterial 16S rRNA sequences, mainly from Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes and Chloroflexi, were obtained per sample. It was found that the continuous cropping of passion fruit increased the richness but reduced the diversity of soil fungi, while it dramatically increased the richness and diversity of soil bacteria. In addition, during the continuous cropping, grafting different scions in the same rootstock contributed to the aggregation of differential rhizosphere microbial communities. Among fungal genera, Trichoderma showed higher abundance in RY than in RP and CS, while the opposite was observed in the pathogen Fusarium. Moreover, the co-occurrence network and potential function analyses also showed that the appearance of Trichoderma was related to Fusarium and its contribution to plant metabolism was significantly greater in RY than in RP and CS. In conclusion, the rhizosphere of yellow passion fruit may be beneficial for the enrichment of disease-resistant microbes, such as Trichoderma, which may be an important factor inducing stronger resistance to stem rot. It will help to form a potential strategy for overcoming the pathogen-mediated obstacles in passion fruit and improve its yield and quality.