bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic diversity and population structure of Tarek (Alburnus tarichi), an endemic species to the Lake Van basin, Turkey
Authors: Çiftci Yılmaz , Eroğlu Oğuzhan , Firidin Şirin , Savaş Hacı , Bektaş Yusuf
Published: March 2021

In this study, the genetic relationships of 804 tarek (Alburnus tarichi) samples from a total of 18 populations, including the potamodromus and resident individuals from Lake Van basin in eastern Turkey, were studied by using nine microsatellite loci. A total of 93 alleles was detected, and the average number of alleles per locus was 10.3 ± 3.39. The mean estimated observed and expected heterozygosity were 0.340 ± 0.016 and 0.362 ± 0.015, respectively, which indicated a low level of polymorphism. After Bonferroni correction (P< 0.0027), the multi-locus test applied to each population revealed that 12 out of 18 populations were in Hardy-Weinberg equilibrium (HWE) (P = 0.0120–0.9981). Analysis of molecular variance (AMOVA) showed more than 76% genetic variability within individuals and 19% among populations, which was significantly higher than zero (FST = 0.19), and furthermore, a low level of genetic variation was observed among individuals within populations (4.84%: FIS = 0.06). Bayesian clustering analysis indicated that the total genetic variation grouped into 3 clusters. Additionally, the significance test results revealed that 11 of the 18 populations are threatened with extinction due to recent bottleneck events.We conclude that the tarek populations from the Lake Van basin can be classified into distinct genetic groups, based on microsatellite information. In addition, our results provide essential information for the development of a management plan that conserves the tarek's genetic diversity and achieves a sustainable fishery.
One-step synthesis of gold nanoparticles carried by boehmite
Authors: Wang Mengyi , Sha Rongxin , Zhang Ziyang , Zou Ailiang , Xu Yuekui , Liu Min , Peng Yibo , Qiu Zhiyong
Published: March 2021

In this work, we proposed a simple method to synthesize gold nanoparticles carried by boehmite, which was made directly from Al/Au bilayer films by a one-step hydrothermal treatment. The boehmite carrier is porous with a special density-gradient structure. As a result, the embedded gold nanoparticles demonstrate good size uniformity, strong surface plasmon resonance, and good affinity for reacting solution. Such nanoparticles carried by boehmite exhibit the high potential of applications as efficient catalysts and sensitive bio-sensors.
Evaluation of Retinal Neurodegeneration and Choroidal Thickness in Patients with Inactive Gravesʼ Ophthalmopathy
Authors: Kurt Muhammed M. , Akpolat Cetin , Evliyaoglu Ferhat , Yilmaz Merve , Ordulu Fikriye
Published: March 2021

Purpose The study was conducted for the assessment of the retinal nerve fiber layer, ganglion cell layer, and subfoveal choroidal thickness changes in patients with inactive Gravesʼ ophthalmopathy (GO) using swept-source optical coherence tomography (SS-OCT) before the development of active GO findings.

Materials and Methods The cross-sectional designed study consisted of patients with inactive Gravesʼ ophthalmopathy (study group) and healthy subjects (control group). The thicknesses of the retinal ganglion cell layer, retinal nerve fiber layer, and subfoveal choroid (SFCT) were measured using SS-OCT with deep range imaging technology to compare these parameters between the study and control groups.

Result Patients with inactive Gravesʼ ophthalmopathy had higher values of intraocular pressure but similar best-corrected visual acuity (p = 0.001, p = 0.232, respectively). The retinal nerve fiber layer was thinner only in the superior zone of the study group (p = 0.039), whereas similar values were noted in the temporal, nasal, and inferior areas as well as the average thickness. We did not observe any statistically significant difference in any sector of the ganglion cell layer between the study and control groups. A thicker mean subfoveal choroidal thickness value was measured in patients with inactive Gravesʼ ophthalmopathy than in healthy subjects (p = 0.013) in correlation with a clinical activity score (p = 0.046).

Conclusion SS-OCT showed minimal retinal neurodegenerative alteration and significant choroidal thickening in inactive GO. Thus, SS-OCT might be a beneficial technique to detect retinal neurodegenerative and choroidal changes earlier in the stage of inactive GO before the development of active GO signs, which may affect the time and type of treatment modalities to prevent further ocular or systemic complications. Additionally, SFCT may be a good indicator for assessment of the severity of Gravesʼ disease.
Impact of COVID-19 Pandemic on Emergency Inpatient Volume at a Tertiary Eye Care Center in Germany with Corneal Main Specialization
Authors: Seitz Berthold , Szentmáry Nóra , Tóth Gábor , Xanthopoulou Kassandra , Stachon Tanja , Németh János , Hécz Réka , Berkó-Göttel Barbara , Pfuhl Thorsten , Smola Sigrun
Published: March 2021

Background To estimate the impact of the COVID-19 pandemic on emergency inpatient volume in a tertiary eye care center in Germany with corneal main subspecialization.

Material and Methods A retrospective review of ocular emergency patients who attended the inpatient unit of the Department of Ophthalmology of Saarland University, Homburg/Saar, Germany during the COVID-19 pandemic, between 1 March and 30 April 2020, in comparison to the same time period in 2019. For each subject, clinical history and surgical reports were reviewed. After 24 March 2020, PCR examinations for SARS-CoV-2 were performed from throat swab specimens in all patients using real-time RT-PCR.

Results Totally, 135 patients were admitted in 2019 and 115 patients in 2020 as emergency cases. The patient age at the time of admission did not differ significantly between the two time periods (63.6 ± 17.9 years vs. 62.5 ± 19.6 years) (p = 0.792), but the average length of hospital stays increased significantly for 2020 (4.0 ± 3.6 vs. 4.4 ± 2.7 days, p = 0.043). The percentage of admissions due to acute corneal hydrops (0% vs. 3.5%) increased significantly from 2019 to 2020 (χ2 = 4.772, p = 0.028), however, there was not a significant difference between the two years for any other diagnosis (χ2 ≤ 3.564, p ≥ 0.059). From 2019 to 2020, the percentage of acute intravitreal anti-VEGF injections decreased significantly (7.9% vs. 1.3%, χ2 = 3.985, p = 0.045), but the proportion of other emergency surgeries did not differ between the two years (χ2 ≤ 3.617, p ≥ 0.057). COVID-19 PCR examination was performed in 66 (57.4%)
cases in 2020 and all samples (100%) were negative.

Conclusions The COVID pandemic did not change emergency inpatient volume in our department, but duration of hospital stay was extended on average by 8 hours, mainly due to additional COVID-19-PCR examinations. The proportion of the most frequently performed surgeries did not change remarkably between 2019 and 2020, but with the introduction of Muraineʼs sutures in 2019, the percentage of admissions with acute corneal hydrops (with or without subsequent surgery) increased for 2020. No urgent surgery had to be postponed due to the COVID-19 pandemic at our department; all operations were performed successfully.
Two-Year Follow-Up: Therapeutic Success with Respect to Axial Length of Stand-Alone Xen45 Gel Stent Implantation and Combined Procedures
Authors: Gernhart Markus , Hohberger Bettina , Laemmer Robert
Published: March 2021

Background Up to now, no data have been available on the therapeutic success rate of Xen45 gel stent with respect to axial length (AL). The present study aimed to investigate a potential influence of AL on therapeutic success in stand-alone Xen45 gel stent implantation or combination with cataract surgery in open-angle glaucoma patients (OAG) with a follow-up of 2 years.

Materials and Methods In this retrospective observational study, 98 eyes of 87 glaucoma patients of the Department of Ophthalmology, University of Erlangen Nürnberg, and from the Erlangen Glaucoma Registry (NCT00494923; ISSN 2191-5008, CS-2011) underwent stand-alone Xen45 gel stent implantation or a combination with cataract surgery. Therapeutic success was defined as ≥ 20% IOP reduction with the same or fewer anti-glaucomatous eye drops needed compared to baseline, yet without additional glaucoma-related surgery (expect bleb needling). Therapeutic failure was classified as any additional glaucoma-related surgery, IOP reduction < 20% or if more local anti-glaucomatous eye drops were applied compared to baseline.

Results The therapeutic success rate was 60.7% (1 year) and 62.5% (2 years). No statistical difference was observed when procedures were combined with cataract surgery (p > 0.05). Subgroup analysis yielded no significantly different therapeutic success when considering glaucoma subtype [1 year: 61.5% (POAG), 60% (SAOG), 2 years: 54.5% (POAG), 69.2% (SOAG); p > 0.05]. Anti-glaucomatous medication use was lowered from 2.72 ± 1.04 at baseline to 0.61 ± 0.99 (1 year) and 0.7 ± 1.04 (2 years). The therapeutic success rate was seen to be independent of axial length for group and subgroup analysis (p > 0.05). Emmetropic eyes (22.0 – 24.5 mm) showed a statistically higher needling rate than myopic eyes (> 24.5 mm, p = 0.02).

Conclusion Minimal invasive glaucoma surgery is one therapeutic option in OAG eyes, with good reduction in IOP even after 24 months (with additional bleb needling). Therapeutic success seemed to be independent of axial length in the present study.
Beta-Glucuronidase Inhibition by Constituents of Mulberry Bark
Authors: Bai Yue , Chen Lu , Cao Yun-Feng , Hou Xu-Dong , Jia Shou-Ning , Zhou Qi , He Yu-Qi , Hou Jie
Published: March 2021

Intestinal bacterial β-glucuronidases, the key enzymes responsible for the hydrolysis of various glucuronides into free aglycone, have been recognized as key targets for treating various intestinal diseases. This study aimed to investigate the inhibitory effects and mechanisms of the Mulberry bark constituents on E. coli β-glucuronidase (EcGUS), the most abundant β-glucuronidases produced by intestinal bacteria. The results showed that the flavonoids isolated from Mulberry bark could strongly inhibit E. coli β-glucuronidase, with IC50 values ranging from 1.12 µM to 10.63 µM, which were more potent than D-glucaric acid-1,4-lactone. Furthermore, the mode of inhibition of 5 flavonoids with strong E. coli β-glucuronidase inhibitory activity (IC50 ≤ 5 µM) was carefully investigated by a set of kinetic assays and in silico analyses. The results demonstrated that these flavonoids were noncompetitive
inhibitors against E. coli β-glucuronidase-catalyzed 4-nitrophenyl β-D-glucuronide hydrolysis, with Ki
values of 0.97 µM, 2.71 µM, 3.74 µM, 3.35 µM, and 4.03 µM for morin (1), sanggenon C (2), kuwanon G (3), sanggenol A (4), and kuwanon C (5), respectively. Additionally, molecular docking simulations showed that all identified flavonoid-type E. coli β-glucuronidase inhibitors could be well-docked into E. coli β-glucuronidase at nonsubstrate binding sites, which were highly consistent with these agentsʼ noncompetitive inhibition mode. Collectively, our findings demonstrated that the flavonoids in Mulberry bark displayed strong E. coli β-glucuronidase inhibition activity, suggesting that Mulberry bark might be a promising dietary supplement for ameliorating β-glucuronidase-mediated intestinal toxicity.
Chaos in conservative discrete-time systems subjected to parameter drift
Authors: Jánosi Dániel , Tél Tamás
Published: March 2021

Based on the example of a paradigmatic area preserving low-dimensional mapping subjected to different scenarios of parameter drifts, we illustrate that the dynamics can best be understood by following ensembles of initial conditions corresponding to the tori of the initial system. When such ensembles are followed, snapshot tori are obtained, which change their location and shape. Within a time-dependent snapshot chaotic sea, we demonstrate the existence of snapshot stable and unstable foliations. Two easily visualizable conditions for torus breakup are found: one in relation to a discontinuity of the map and the other to a specific snapshot stable manifold, indicating that points of the torus are going to become subjected to strong stretching. In a more general setup, the latter can be formulated in terms of the so-called stable pseudo-foliation, which is shown to be able to extend beyond the instantaneous chaotic sea. The average distance of nearby point pairs initiated on an original torus crosses over into an exponential growth when the snapshot torus breaks up according to the second condition. As a consequence of the strongly non-monotonous change of phase portraits in maps, the exponential regime is found to split up into shorter periods characterized by different finite-time Lyapunov exponents. In scenarios with plateau ending, the divided phase space of the plateau might lead to the Lyapunov exponent averaged over the ensemble of a torus being much smaller than that of the stationary map of the plateau.
Effective normal modes identify vibrational motions which maximally promote vibronic mixing in excitonically coupled aggregates
Authors: Patra Sanjoy , Sahu Amitav , Tiwari Vivek
Published: March 2021

Controlling energy transfer through vibronic resonance is an interesting possibility. Exact treatment of non-adiabatic vibronic coupling is necessary to fully capture its role in driving energy transfer. However, the exact treatment of vibrations in extended systems is expensive, sometimes requiring oversimplifying approximations to reduce vibrational dimensionality, and do not provide physical insights into which specific vibrational motions promote energy transfer. In this communication, we derive effective normal modes for understanding vibronically enhanced energy transfer in excitonically coupled aggregates. We show that the dynamics of the overall high-dimensional vibronic Hamiltonian can be better understood through one-dimensional Hamiltonians separable along these effective modes. We demonstrate this approach on a trimer toy model to analyze the role of an intermediate “trap” site in mediating energy transfer between electronically uncoupled sites. Bringing uncoupled sites into vibronic resonance converts the “trap” into a “shuttle” for energy transfer. By deconvolving the dynamics along the aggregate normal modes, our approach identifies the specific vibrational motions, which maximally promote energy transfer, against spectator modes, which do not participate in vibronic mixing.
Updates to the Oxford Space Environment Goniometer to measure visible wavelength bidirectional reflectance distribution functions in ambient conditions
Authors: Curtis R. J. , Warren T. J. , Bowles N. E.
Published: March 2021

Understanding how the surfaces of airless planetary bodies—such as the Moon—scatter visible light enables constraints to be placed on their surface properties and top boundary layer inputs to be set within thermal models. Remote sensing instruments—such as Diviner onboard the Lunar Reconnaissance Orbiter—measure thermal emission and visible light scattering functions across visible (∼0.38–0.7 µm) to thermal infrared (TIR) wavelengths (∼0.7–350 μm). To provide ground support measurements for such instruments, the Oxford Space Environment Goniometer (OSEG) was built. Initially, the OSEG focused on measuring TIR directional emissivity functions for regolith and regolith simulant samples in a simulated space environment, but it has recently been modified to measure visible wavelength Bidirectional Reflectance Distribution Functions (BRDFs) of samples in ambient conditions. Laboratory-measured BRDFs can be used (1) to test and to help interpret models—such as the Hapke photometric model—and (2) as visible scattering function inputs for thermal models. This paper describes the modifications to and initial calibration measurements taken by the Visible Oxford Space Environment Goniometer with a 532 nm laser, and details how this setup can be used to measure BRDFs of regolith and regolith simulant samples of airless planetary bodies.
Electric circuit model of microwave optomechanics
Authors: Zhou Xin , Cattiaux Dylan , Theron Didier , Collin Eddy
Published: March 2021

We report on the generic classical electric circuit modeling that describes standard single-tone microwave optomechanics. Based on a parallel RLC circuit in which a mechanical oscillator acts as a movable capacitor, derivations of analytical expressions are presented, including key features such as the back-action force, the input–output expressions, and the spectral densities associated, all in the classical regime. These expressions coincide with the standard quantum treatment performed in optomechanics when the occupation number of both cavity and mechanical oscillator are large. Besides, the derived analytics transposes optical elements and properties into electronics terms, which is mandatory for quantitative measurement and design purposes. Finally, the direct comparison between the standard quantum treatment and the classical model addresses the bounds between quantum and classical regimes, highlighting the features which are truly quantum, and those which are not.
Why do anguilliform swimmers perform undulation with wavelengths shorter than their bodylengths?
Authors: Khalid Muhammad Saif Ullah , Wang Junshi , Akhtar Imran , Dong Haibo , Liu Moubin , Hemmati Arman
Published: March 2021

Understanding the connection between physiology and kinematics of natural swimmers is of great importance to design efficient bio-inspired underwater vehicles. This study looks at high-fidelity three-dimensional numerical simulations for flows over an undulating American eel with prescribed anguilliform kinematics. Particularly, our work focuses on why natural anguilliform swimmers employ wavelengths shorter than their bodylengths while performing wavy kinematics. For this purpose, we vary the undulatory wavelength for a range of values generally observed in different aquatic animals at Strouhal numbers 0.30 and 0.40. We observe that our anguilliform swimmer is able to demonstrate more suitable hydrodynamic performance for wavelengths of 0.65 and 0.80. For longer wavelengths, the swimmer experiences large frictional drag, which deteriorates its performance. The wake topology was dominated by hairpin-like structures, which are closely linked with the underlying physics of anguilliform swimming found in nature.
High-velocity micro-projectile impact testing
Authors: Veysset David , Lee Jae-Hwang , Hassani Mostafa , Kooi Steven E. , Thomas Edwin L. , Nelson Keith A.
Published: March 2021

High-velocity microparticle impacts are relevant to many fields, from space exploration to additive manufacturing, and can be used to help understand the physical and chemical behaviors of materials under extreme dynamic conditions. Recent advances in experimental techniques for single microparticle impacts have allowed fundamental investigations of dynamical responses of wide-ranging samples, including soft materials, nano-composites, and metals, under strain rates up to 108 s−1. Here we review experimental methods for high-velocity impacts spanning 15 orders of magnitude in projectile mass and compare method performances. This review aims to present a comprehensive overview of high-velocity microparticle impact techniques to provide a reference for researchers in different materials testing fields and facilitate experimental design in dynamic testing for a wide range of impactor sizes, geometries, and velocities. Next, we review recent studies using the laser-induced particle impact test platform comprising target, projectile, and synergistic target-particle impact response, hence demonstrating the versatility of the method with applications in impact protection and additive manufacturing. We conclude by presenting the future perspectives in the field of high-velocity impact.
Frequency comb referenced spectroscopy of A–X 0–0 transitions in SH
Authors: Fast Arthur , Meek Samuel A.
Published: March 2021

We report absolute transition frequencies for the allowed transitions from the X2Π3/2, v″ = 0, J″ = 3/2 rovibronic ground state of 32S1H to the A2Σ+, v′ = 0 vibronic state. The frequencies have been determined with an uncertainty of less than 1 MHz, representing a more than 1000-fold improvement over previous measurements. Spectral traces are measured by scanning a frequency comb stabilized continuous-wave spectroscopy laser over the molecular transitions and detecting laser-induced fluorescence from SH molecules in a highly collimated molecular beam. To determine the absolute transition frequencies, the traces are fit with a quantum-mechanical model that accounts for saturation effects and shifts due to quantum interference. The model also provides estimates of the predissociation rate of the excited-state levels. Weighted averages of the hyperfine-resolved transition frequencies are computed in order to enable comparisons to measurements where the hyperfine structure is not resolved. These hyperfine-averaged frequencies indicate that the absolute transition frequencies determined in previous measurements were about ∼2.1 GHz (0.07 cm−1) too high. Finally, the measured transition frequencies are fit using an effective Hamiltonian model, resulting in more precise estimates of the spectroscopic constants.
Characterization of H2O transport through Johnson Space Center number 1A lunar regolith simulant at low pressure for in-situ resource utilization
Authors: Schieber Garrett L. , Jones Brant M. , Orlando Thomas M. , Loutzenhiser Peter G.
Published: March 2021

H2O transport through a packed bed of Johnson Space Center number 1A (JSC-1A) lunar regolith simulant was examined at relevant temperatures and pressures for in-situ resource utilization (ISRU) on the Moon. Experimentation was conducted over a range of pressures from 50 to 2065 Pa at ∼350 K, corresponding to Knudsen numbers of 0.3 < Kn < 11. Pressure and temperature conditions were relevant toward ISRU technologies. A piecewise function was used to evaluate transition and Knudsen regime flows. The piecewise model utilized a Knudsen number that predicted the transition point between advective and Knudsen flows. A transition Knudsen number of 1.66 ± 0.61 and a tortuosity shape parameter of 0.736 ± 0.13 were determined from non-linear regression, and Knudsen diffusivities of 10.62 cm2·s−1, 10.40 cm2·s−1, and 9.04 cm2·s−1 for packed beds of JSC-1A with porosities of 0.388, 0.385, and 0.365, respectively. The experimental measurements, methodology, and modeling provide useful information for ISRU technologies involving the transport of volatiles (e.g., thermal extraction of H2O).
Improved motional Stark effect signal processing using fast Fourier transform spectral analysis
Authors: Makowski M. A. , Victor B. S.
Published: March 2021

A Fast Fourier Transform (FFT) based method has been developed, which improves the frequency response of the Motional Stark Effect (MSE) system by about a factor of 10 over the conventional analog lock-in method. The method uses fits to rigorously derived analytic expressions for the FFT spectral components of the MSE signal to accurately obtain the amplitudes and phases of the 2f1 and 2f2 photo-elastic modulator (PEM) frequencies that encode the polarization angle. Since no frequency filtering is used in the FFT method, the frequency response is limited by fundamental measurement properties: the frequency response of the detector, photon statistics, sample rate, and the ability to resolve the spectral components. In contrast, the frequency response of the analog lock-in is limited by a low pass filter with a cutoff of around 500 Hz. In the case of the DIII-D MSE system, the output of the photo-multiplier tube detector was sampled at 500 kHz and FFTs with as few as 100 points were used to obtain the amplitudes of the 2f1 and 2f2 PEM frequency components. This corresponds to a frequency response of 5 kHz, about ten times faster than the analog lock-in amplifier system. Details of the FFT method will be presented and compared to those of the analog lock-in system.
An improved equation of state for air plasma simulations
Authors: Träuble F. , Millmore S. T. , Nikiforakis N.
Published: March 2021

This work is concerned with the development of a novel, accurate equation of state for describing partially ionized air plasma in local thermodynamic equilibrium. One key application for this new equation of state is the simulation of lightning strike on aircraft. Due to the complexities of species ionization and interaction, although phenomenological curve fitting of thermodynamic properties is possible, these curves are intractable for practical numerical simulation. The large difference in size of the parameters (many orders of magnitude) and complexity of the equations means they are not straightforward to invert for conversion between thermodynamic variables. The approach of this paper is to take an accurate 19-species phenomenological model and use this to generate a tabulated dataset. Coupled with a suitable interpolation procedure, this offers an accurate and computationally efficient technique for simulating partially ionized air plasma. The equation of state is implemented within a multiphysics methodology which can solve for two-way coupling between a plasma arc and an elastoplastic material substrate. The implementation is validated against experimental results, both for a single material plasma and an arc coupled to a substrate. It is demonstrated that accurate, oscillation-free thermodynamic profiles can be obtained, with good results even close to material surfaces.
Receptivity to forcing disturbances in subcritical liquid sheet flows
Authors: Della Pia Alessandro , Chiatto Matteo , de Luca Luigi
Published: March 2021

The receptivity to forcing harmonic disturbances of transverse velocity in subcritical liquid sheet flows subjected to gravity is studied. The investigation is carried out both by employing the linear stability theory applied to a simplified one-dimensional inviscid model and by performing fully two-dimensional numerical simulations based on the Volume-of-Fluid technique. The computation of global sinuous eigenmodes and eigenvalues has required the removal of the singularity of the governing equation, for the first time carried out in the case of unconfined gaseous ambient. Direct numerical simulations of the unsteady sheet when continuously forced by a perturbation in lateral velocity are reported. The harmonic forcing, applied at the inlet section, basically excites sinuous modes of the system, related to the natural impulse response. The results of receptivity have been treated by employing a proper one-dimensional reduction technique to compare numerical data with the corresponding findings of the stability theory. Depending on the Reynolds number, two different behaviors are observed: at low Re the large viscous effect makes the system overdamped; as Re increases and the inviscid conditions are approaching, the frequency response exhibits a peak frequency (resonance) which closely agrees with the frequency of the least stable eigenvalue. The various stations synchronize with the critical station as Re increases, and therefore it forces the global oscillations of the flow field. This behavior of the critical station retrieves the role of wavemaker, which fails for high-frequency forcing. The resonance characteristics of the sheet have been further analyzed by inspecting the fully two-dimensional velocity fields. A major finding at low forcing frequency is the nonlinear varicose distortion of the sheet thickness that progressively envelops the basic sinuous shape when the inviscid conditions are approaching.
Construction of linearly independent non-orthogonal AGP states
Authors: Dutta Rishab , Chen Guo P. , Henderson Thomas M. , Scuseria Gustavo E.
Published: March 2021

We show how to construct a linearly independent set of antisymmetrized geminal power (AGP) states, which allows us to rewrite our recently introduced geminal replacement models as linear combinations of non-orthogonal AGPs. This greatly simplifies the evaluation of matrix elements and permits us to introduce an AGP-based selective configuration interaction method, which can reach arbitrary excitation levels relative to a reference AGP, balancing accuracy and cost as we see fit.
Bubble hydrodynamics and mass transfer in stirred tank with non-Newtonian fluids: Scale-up from laboratory to pilot-scale
Authors: Ali Haider , Solsvik Jannike
Published: March 2021

Mass transfer is a crucial phenomenon in designing and scaling up chemical and biochemical stirred tanks. The literature lacks a pilot-scale study on investigating mass transfer in non-Newtonian fluids. A pilot-scale study is a prerequisite step before scaling up the process from laboratory to industrial-scale. Thus, a study using pilot-scale stirred tank was conducted to investigate bubble hydrodynamics and mass transfer in non-Newtonian fluids. This work is a scale-up study from laboratory to pilot-scale. Axial distributions of bubble–liquid mass transfer coefficient and interfacial area were obtained using dedicated in situ optical endoscope probes (oxygen and bubble size) simultaneously. Volumetric mass transfer coefficient was determined by recording local dissolved oxygen concentrations in liquid. Interfacial area was estimated by measuring local bubble size and global gas holdup. Bubble–liquid mass transfer coefficient was then deduced by combining the obtained values of volumetric mass transfer coefficient and interfacial area. Effects of operating conditions, fluid rheology, and probe axial positions (liquid height) on bubble–liquid mass transfer coefficient were considered. The operating conditions (power inputs and superficial gas velocities) were in the range of 30–250 W/m3 and 3.10–4.70 mm/s, respectively. Bubble–liquid mass transfer coefficient increased with an increase in operating conditions, whereas it decreased with an increase in fluid rheology and liquid height. Scale-up effects on mass transfer were higher for water than viscous fluids, as suggested by large deviation (9.6%) in values of bubble–liquid mass transfer coefficient.
High power and high repetition frequency sub-nanosecond pulse generator with two-phase immersion cooling technique
Authors: Ren Linyuan , Wang Yanan , Yang Zihao , Ding Weidong
Published: March 2021

In this paper, a 60-stage Marx circuit with the two-phase immersion cooling technique is presented. The performance parameters of the pulse generator with phase change immersion cooling and forced air cooling are compared. The results show that the maximum repetition rate is increased from 80 to 260 kHz, the pulse drift is significantly reduced from 900 to 200 ps, and the temperature rise of transistors is controlled effectively to enhance the stability of the amplitude. We also studied the influence of temperature on the turn-on and turn-off processes of the transistors to show the importance of heat management under high repetition conditions. Finally, a pulse generator is developed with the repetition rate of 200 kHz, the rise time of 180 ps, and the amplitude of 2350 V on a matched 50 Ω resistive load, which can work for more than 30 min.
Fine-scale vertical habitat use of white sharks at an emerging aggregation site and implications for public safety
Authors: Winton Megan V. , Sulikowski James , Skomal Gregory B.
Published: March 2021

Abstract Context Over the past decade, the coastal waters off Cape Cod, Massachusetts, have emerged as the only known aggregation site for the white shark (Carcharodon carcharias) in the western North Atlantic. During periods of seasonal residency, white sharks patrol the shoreline in search of pinniped prey, bringing them in close proximity to popular beaches where people recreate. Aim To examine whether white sharks off Cape Cod are more likely to occupy shallow depths (and consequently more likely to overlap with recreational water users) under certain conditions. Methods We deployed short-term, pop-up satellite archival transmitting (PSAT) tags and acoustic transmitters on 14 subadult and adult white sharks off the coast of Cape Cod during the summer and fall of 2017. PSAT tags provided fine-scale depth and temperature data, which were combined with high-resolution location data obtained from an acoustic telemetry array, to identify the depth and temperature preferences of white sharks when resident in the area. Key results Sharks spent the majority (95%) of tracked time at depths of 0–31 m and at temperatures from 8.9°C to 20.7°C. During resident periods along Cape Cod, individuals spent almost half (47%) of their time at depths of less than 4.5 m, but made frequent excursions to mid-shelf depths, alternating between the surf zone and deeper offshore waters. Sharks were slightly more likely to occupy shallow depths at night during the new moon. The relationship between shark depth and lunar phase varied over the course of the day, suggesting the mechanism underlying lunar effects differs among diel periods. Conclusions Although the overall risk posed to humans by white sharks is low, there is a high potential for overlap between white sharks and recreational water users off Cape Cod. The risk of interaction may be slightly higher during periods when local environmental conditions favour the species’ predatory stealth by influencing prey behaviour or detectability. Implications This study provides the first glimpse into the fine-scale vertical habitat use of white sharks off Cape Cod, which can be used to better understand the risk to recreational water users and to inform public safety practices.
An overview of the history, current contributions and future outlook of iNaturalist in Australia
Authors: Mesaglio Thomas , Callaghan Corey T.
Published: March 2021

Citizen science initiatives and the data they produce are increasingly common in ecology, conservation and biodiversity monitoring. Although the quality of citizen science data has historically been questioned, biases can be detected and corrected for, allowing these data to become comparable in quality to professionally collected data. Consequently, citizen science is increasingly being integrated with professional science, allowing the collection of data at unprecedented spatial and temporal scales. iNaturalist is one of the most popular biodiversity citizen science platforms globally, with more than 1.4 million users having contributed over 54 million observations. Australia is the top contributing nation in the southern hemisphere, and in the top four contributing nations globally, with over 1.6 million observations of over 36 000 identified species contributed by almost 27 000 users. Despite the platform’s success, there are few holistic syntheses of contributions to iNaturalist, especially for Australia. Here, we outline the history of iNaturalist from an Australian perspective, and summarise, taxonomically, temporally and spatially, Australian biodiversity data contributed to the platform. We conclude by discussing important future directions to maximise the usefulness of these data for ecological research, conservation and policy.
Rules of contact inhibition of locomotion for cells on suspended nanofibers
Authors: Singh Jugroop , Pagulayan Aldwin , Camley Brian A. , Nain Amrinder S.
Published: March 2021

Significance

When cells heal a wound or invade a new area, they coordinate their motion. Coordination is often studied by looking at what happens after pairs of cells collide. Postcollision, cells often exhibit contact inhibition of locomotion—they turn around and crawl away from the point where they touched. Past knowledge of repolarization on contact comes from studies on flat surfaces, unlike cells in the body, which crawl along fibers. We discover that cells on single fibers walk past one another, but cells in contact with multiple fibers stick to one another and move as pairs. This outcome changes to walk past after cell division. Our experiments and models reveal how the environment regulates cell–cell coordination after contact.
Parameter-free molecular super-structures quantification in single-molecule localization microscopy
Authors: Marenda Mattia , Lazarova Elena , van de Linde Sebastian , Gilbert Nick , Michieletto Davide
Published: March 2021

Understanding biological function requires the identification and characterization of complex patterns of molecules. Single-molecule localization microscopy (SMLM) can quantitatively measure molecular components and interactions at resolutions far beyond the diffraction limit, but this information is only useful if these patterns can be quantified and interpreted. We provide a new approach for the analysis of SMLM data that develops the concept of structures and super-structures formed by interconnected elements, such as smaller protein clusters. Using a formal framework and a parameter-free algorithm, (super-)structures formed from smaller components are found to be abundant in classes of nuclear proteins, such as heterogeneous nuclear ribonucleoprotein particles (hnRNPs), but are absent from ceramides located in the plasma membrane. We suggest that mesoscopic structures formed by interconnected protein clusters are common within the nucleus and have an important role in the organization and function of the genome. Our algorithm, SuperStructure, can be used to analyze and explore complex SMLM data and extract functionally relevant information.
In silico simulations reveal that RYR distribution affects the dynamics of calcium release in cardiac myocytes
Authors: Iaparov Bogdan I. , Zahradnik Ivan , Moskvin Alexander S. , Zahradníková Alexandra
Published: March 2021

The dyads of cardiac myocytes contain ryanodine receptors (RYRs) that generate calcium sparks upon activation. To test how geometric factors of RYR distribution contribute to the formation of calcium sparks, which cannot be addressed experimentally, we performed in silico simulations on a large set of models of calcium release sites (CRSs). Our models covered the observed range of RYR number, density, and spatial arrangement. The calcium release function of CRSs was modeled by RYR openings, with an open probability dependent on concentrations of free Ca2+ and Mg2+ ions, in a rapidly buffered system, with a constant open RYR calcium current. We found that simulations of spontaneous sparks by repeatedly opening one of the RYRs in a CRS produced three different types of calcium release events (CREs) in any of the models. Transformation of simulated CREs into fluorescence signals yielded calcium sparks with characteristics close to the observed ones. CRE occurrence varied broadly with the spatial distribution of RYRs in the CRS but did not consistently correlate with RYR number, surface density, or calcium current. However, it correlated with RYR coupling strength, defined as the weighted product of RYR vicinity and calcium current, so that CRE characteristics of all models followed the same state-response function. This finding revealed the synergy between structure and function of CRSs in shaping dyad function. Lastly, rearrangements of RYRs simulating hypothetical experiments on splitting and compaction of a dyad revealed an increased propensity to generate spontaneous sparks and an overall increase in calcium release in smaller and more compact dyads, thus underlying the importance and physiological role of RYR arrangement in cardiac myocytes.
Parametric FEM modeling of multilayer castellated canted cosine theta (CCT) magnets
Authors: Ortwein Rafal , Kirby Glyn
Published: March 2021

Canted cosine theta (CCT) magnets have received increased attention in the recent years due to their inherent characteristics of high field quality and low conductor stresses, as each turn is supported by the metallic former. CCT geometry is suitable for complex magnets—such as nested dipoles, which allow full 360° control of the magnetic field direction. Modeling and design of such magnets is the subject of this work. A parametric 3D modeling framework for multilayer CCT magnets has been developed and optimized allowing efficient model generation without a need for both: CAD software and time consuming meshing. The model has been created using the APDL scripting language and solved using the Ansys software. By direct generation of nodes and elements the time to generate a model with one million elements was of the order of 10 min. A framework for script generation was developed, as well as the relations between the mesh parameters and the total number of nodes and elements. Detailed mesh dependence study was carried-out with in-depth analysis of solver performance (solution time, amount of written data, RAM requirements). Global and local convergence criteria were introduced to find the optimal mesh size. The case of a four layer 2.5 Tm nested dipole was analyzed in details including the worst-case scenario with full debonding between the CCT layers. Thanks to the castellations the nested-dipole is safe to support 144 000 Nm of torque due to Lorentz forces even with full de-bonding between the layers.
Zero-energy corner states protected by generalized chiral symmetry in C
4 symmetric crystals
Authors: Li Yu-Zeng , Liu Zheng-Fang , Xu Xun-Wei , Wu Qing-Ping , Xiao Xian-Bo , Liu Mei-Rong , Chang Lu-Lu , Zhang Ruo-Long
Published: March 2021

We investigated the corner-states characteristics of C
4-symmetric higher-order topological crystalline insulators. By evaluating the charge polarization and fractional corner charge, we obtained the abundant topological properties for different intercell hoppings amplitudes and identified that the non-trivial fractional corner charges are accompanied by second-order topological corner states. Interestingly, there are two different types of corner states topologically protected by generalized chiral symmetry, which guarantees that both corner states are pinned to zero energy. One of the corner states is localized at the corners like the one protected by generalized chiral symmetry of three-atom sublattice. However, the other corner states are localized at the two sublattices nearest to the corners, which has no counterpart in a lattice with generalized chiral symmetry. Moreover, both of them have robustness against defects and disorder.
A Multi-response Aluminum Metal-organic Frameworks for Fluorescence Sensing of Fe3+, Sr2+, SiO3
2− and Toluene
Authors: Ma Xuelin , Zhang Xiaoyong , Han Limin , Hao Zhanzhong , Yong Shengli
Published: March 2021

A new Aluminum metal-organic frameworks(Al-MOF) based on tricarboxylate ligands(L){L = 2,2’,2’-([1,3,5]-triazine-2,4,6-triimino)tribenzoic acid)} has been designed and synthesized. It can be served as a platform of multi-responsive fluorescence sensor for Fe3+, Sr2+ and SiO3
2− in water, which is mainly due to the significant enhancement effect of these ions on the fluorescence intensity of Al-MOF. Especially, Fe3+ ions are rarely able to induce MOFs fluorescence enhancement. The limit of detection for three kinds of ions is 6.62* 10−6 M, 5.37* 10−6 M, 6.85* 10−10 M respectively. Meanwhile, It can also be used as a multi-response fluorescence probe to detect toluene in DMF solution, limit of detection is 9.16* 10−3 M respectively. The structure of Al-MOF was characterized by FTIR, 1H NMR, SEM, TAG, PXRD and element analysis. The PXRD showed that the structure of Al-MOF remained the high water stability and pH stability. The application of water samples and vegetables showed that Al-MOF had high sensitive detection for Fe3+ ions.
Assessing Disparities in Reduction Mammaplasty: There Is Room for Improvement
Authors: Morris Martin P , Christopher Adrienne N , Patel Viren , Broach Robyn B , Fischer John P , Butler Paris D
Published: March 2021

Background

Racial and socioeconomic disparities in access and quality of surgical care are well documented in many surgical subspecialties, including plastic surgery.

Objectives

The authors aimed to determine if demographic disparities exist in preoperative and postoperative satisfaction after breast reduction mammaplasty, utilizing patient-reported quality of life (QoL) scores.

Methods

Patients who underwent breast reduction mammaplasty between 2015 and 2020 were identified. Patients who underwent complex concomitant procedures were excluded. Patient demographics and QoL, as measured by the BREAST-Q, were extracted. Wilcoxon Rank Sum and Kruskal-Wallis tests were employed to compare QoL scores across demographic subgroups.

Results

A total of 115 patients met the inclusion criteria. QoL improved across all 4 BREAST-Q domains (all P < 0.001). Disparities were shown to exist in the following: median income vs postoperative satisfaction with information (P < 0.001), BMI vs preoperative physical well-being (P < 0.001), and ethnicity vs preoperative physical well-being (P = 0.003). A sub-group analysis of Caucasian patients compared with Black/African American patients revealed significant inequalities in BMI (P < 0.001), median income by zip code (P < 0.001), improvement in satisfaction with breasts (P = 0.039), satisfaction with information (P = 0.007), and satisfaction with office staff (P = 0.044).

Conclusions

Racial and socioeconomic inequalities exist in preoperative and postoperative satisfaction for patients undergoing breast reduction mammaplasty. Institutions should focus on developing tools for equitable and inclusive patient education and perioperative counseling.

Level of Evidence: 2
A Bayesian semiparametric approach for inference on the population partly conditional mean from longitudinal data with dropout
Authors: Josefsson Maria , Daniels Michael J , Pudas Sara
Published: March 2021

Studies of memory trajectories using longitudinal data often result in highly nonrepresentative samples due to selective study enrollment and attrition. An additional bias comes from practice effects that result in improved or maintained performance due to familiarity with test content or context. These challenges may bias study findings and severely distort the ability to generalize to the target population. In this study, we propose an approach for estimating the finite population mean of a longitudinal outcome conditioning on being alive at a specific time point. We develop a flexible Bayesian semiparametric predictive estimator for population inference when longitudinal auxiliary information is known for the target population. We evaluate the sensitivity of the results to untestable assumptions and further compare our approach to other methods used for population inference in a simulation study. The proposed approach is motivated by 15-year longitudinal data from the Betula longitudinal cohort study. We apply our approach to estimate lifespan trajectories in episodic memory, with the aim to generalize findings to a target population.
Sexual violence as a sexual script in mainstream online pornography
Authors: Vera-Gray Fiona , McGlynn Clare , Kureshi Ibad , Butterby Kate
Published: March 2021

This article examines the ways in which mainstream pornography positions sexual violence as a normative sexual script by analysing the video titles found on the landing pages of the three most popular pornography websites in the United Kingdom. The study draws on the largest research sample of online pornographic content to date and is unique in its focus on the content immediately advertised to a new user. We found that one in eight titles shown to first-time users on the first page of mainstream porn sites describe sexual activity that constitutes sexual violence. Our findings raise serious questions about the extent of criminal material easily and freely available on mainstream pornography websites and the efficacy of current regulatory mechanisms.