bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Practice Patterns of Speech-Language Pathologists Delivering Dysphagia Services to Persons with COPD: Analysis of Survey Outcomes
Authors: Drulia Teresa , Hodge Alexis
Published: November 2021

Swallowing impairments co-occur with chronic obstructive pulmonary disease (COPD) leading to aspiration, disease exacerbations, and malnutrition. This pilot survey study aimed to identify current clinical practice patterns for swallowing evaluation and treatment in persons with COPD. A 35-question Qualtrics survey was deployed to medical speech-language pathology (SLP) social media sites and professional boards; flyers were distributed at a professional conference. Forty-eight SLPs completed the study. SLPs routinely include a clinical swallow examination (96%), videofluoroscopic swallowing study (79%), adjunctive respiratory measures (respiratory rate [83%], and pulse oximetry [67%], respiratory–swallow pattern [77%]) but less frequently include fiberoptic endoscopic evaluation of swallowing (23%). Self-reported advanced clinical experience and expert respiratory analysis skills were associated with adjunctive respiratory measure (respiratory rate, pulse oximetry) inclusion during assessment. Compensatory strategy training (77%) is a preferred treatment for dysphagia in COPD; however, respiratory–swallow pattern training and expiratory muscle strength training are increasing in use. SLPs self-report a comprehensive, individualized patient-centered care approach with inclusion of adjunctive respiratory-focused methods in dysphagia evaluation and treatment practice in persons with COPD. Advances in the identification of the integral role of respiratory function in swallowing integrity may be translating to clinical practice methods for dysphagia management in persons with COPD.
Challenges in Service Provision to Children and Families from Linguistically Diverse Backgrounds
Authors: Fumero Keisey , Torres-Chavarro Michelle , Wood Carla
Published: November 2021

The purpose of this study was to examine and describe experiences and perceptions of speech-language pathologists (SLPs) serving children and families from culturally and linguistically diverse populations. Twenty SLPs were interviewed using an online audio platform regarding common practices, resources and supports, challenges, and communication. Participants' responses to the semi-structured questions were transcribed and analyzed to identify themes in experiences. Results suggested six overall themes including: considerations for assessment; cultural impact; linguistic access and barriers; professional preparedness; impact of COVID-19; and helpful tips and resources. The discussion includes recommendations and resources to address obstacles.
Protamine—The Journey from DNA to Heparin Neutralization to Gene therapy
Authors: Thachil Jecko
Published: November 2021

Protamine is now well recognized as a key heparin neutralizing agent. However, protamine was discovered over a century ago, during experiments performed to uncover the secrets behind heritability. Although protamine was discovered as a highly charged protein, it did not receive the attention it deserved until the dawn of insulin era, when it was used to create the neutral protamine Hagedorn formulation. Based on the same principles, protamine was identified to neutralize heparin and has since been used successfully for many years in cardiothoracic surgery. More recently, its clinical applications have extended to gene therapy. In this historical sketch, the journey from the discovery of protamine, onwards to heparin neutralization, and up to its utilization in genetic modulatory treatments is detailed.
Design, Implementation, and Validation of an Automated, Algorithmic COVID-19 Triage Tool
Authors: Meer Elana A. , Herriman Maguire , Lam Doreen , Parambath Andrew , Rosin Roy , Volpp Kevin G. , Chaiyachati Krisda H. , McGreevey John D.
Published: November 2021

Objective We describe the design, implementation, and validation of an online, publicly available tool to algorithmically triage patients experiencing severe acute respiratory syndrome coronavirus (SARS-CoV-2)-like symptoms.

Methods We conducted a chart review of patients who completed the triage tool and subsequently contacted our institution's phone triage hotline to assess tool- and clinician-assigned triage codes, patient demographics, SARS-CoV-2 (COVID-19) test data, and health care utilization in the 30 days post-encounter. We calculated the percentage of concordance between tool- and clinician-assigned triage categories, down-triage (clinician assigning a less severe category than the triage tool), and up-triage (clinician assigning a more severe category than the triage tool) instances.

Results From May 4, 2020 through January 31, 2021, the triage tool was completed 30,321 times by 20,930 unique patients. Of those 30,321 triage tool completions, 51.7% were assessed by the triage tool to be asymptomatic, 15.6% low severity, 21.7% moderate severity, and 11.0% high severity. The concordance rate, where the triage tool and clinician assigned the same clinical severity, was 29.2%. The down-triage rate was 70.1%. Only six patients were up-triaged by the clinician. 72.1% received a COVID-19 test administered by our health care system within 14 days of their encounter, with a positivity rate of 14.7%.

Conclusion The design, pilot, and validation analysis in this study show that this COVID-19 triage tool can safely triage patients when compared with clinician triage personnel. This work may signal opportunities for automated triage of patients for conditions beyond COVID-19 to improve patient experience by enabling self-service, on-demand, 24/7 triage access.
Multiaxial miniature testing system developed to measure materials at small-length scales
Authors: Frank Jodi Ackerman
Published: November 2021

Device measures multiple properties of miniature components while producing uniform heating.
A synchronous demodulation technology based on sample-and-hold for eddy current sensors
Authors: Zhao Guo Feng , Wu Lei , Feng Zi Long , Zhang Yong , Ni Ji Jun , Feng Zhi Hua
Published: November 2021

This paper proposes a synchronous demodulation technology based on sample-and-hold which shows significant advantages in the application of precision sensors. The traditional synchronous demodulation methods are discussed, and then the working principle of the proposed method is theoretically analyzed in detail. It is found that the proposed method can not only effectively suppress the harmonic components caused by the signal source but is also beneficial to improving the dynamic range of precision sensors. The eddy current sensor is adopted as an example of precision sensors, and a high-precision eddy current displacement sensor prototype was designed and tested. The results show that with the proposed method, the harmonics in the output signal are suppressed more effectively, and the demodulation circuit is relatively simplified. This synchronous demodulation method has an extensive application prospect in precision sensors.
In situ x-ray diffraction of high density polyethylene during dynamic drive: Polymer chain compression and decomposition
Authors: Huber Rachel C. , Watkins Erik B. , Dattelbaum Dana M. , Bartram Brian D. , Gibson Lloyd L. , Gustavsen Richard L.
Published: November 2021

Polymers are widely implemented materials often used for safety and security in our daily lives. However, we do not have a thorough understanding of the phase transformations of these materials when exposed to extreme condition, high strain rate events. To study polymers in these severe environments, we performed plate impact experiments that impart a one-dimensional shockwave, at high pressures and temperatures, to observe the materials response. Generally, velocimetry is the experimental diagnostic used to capture the movement of high velocity interfaces to then calculate the mechanical variables associated with shock compression. However, when a material undergoes a phase transition, such as between two crystalline phases or melting to decomposition during shock compression, velocimetry does not explicitly indicate what structural change occurred. At the Dynamic Compression Sector at the Advanced Photon Source, gas gun driven compression has been paired with x-ray diffraction, providing the ability to study both the shock parameters and structural changes concurrently. We explored high density polyethylene (HDPE) both on its reactants Hugoniot (<10.12 GPa) and within its transition region (24.3  GPa) where HDPE is hypothesized to decompose from reactants to products. With x-ray diffraction, we observed both polymer chain compression and crystal structure reorientation from orthorhombic to monoclinic above 6  GPa as well as either a possible phase change or chemical decomposition at 24.3 GPa. With these experiments, we were able to determine the crystalline and amorphous Hugoniot loci at pressures below the polymer transition region.
Optoelectronic sampling of ultrafast electric transients with single quantum dots
Authors: Widhalm Alex , Krehs Sebastian , Siebert Dustin , Sharma Nand Lal , Langer Timo , Jonas Björn , Reuter Dirk , Thiede Andreas , Förstner Jens , Zrenner Artur
Published: November 2021

In our work, we have engineered low capacitance single quantum dot photodiodes as sensor devices for the optoelectronic sampling of ultrafast electric signals. By the Stark effect, a time-dependent electric signal is converted into a time-dependent shift of the transition energy. This shift is measured accurately by resonant ps laser spectroscopy with photocurrent detection. In our experiments, we sample the laser synchronous output pulse of an ultrafast CMOS circuit with high resolution. With our quantum dot sensor device, we were able to sample transients below 20 ps with a voltage resolution in the mV-range.
The magnetic structure of long-wavelength magnetohydrodynamic modes in current-carrying stellarator plasmas
Authors: Pandya M. D. , Ennis D. A. , Hanson J. D. , Hartwell G. J. , Maurer D. A.
Published: November 2021

Magnetic field fluctuations are observed in current-carrying stellarator plasmas when the rotational transform is close to a rational value at the edge of the plasma. At low plasma pressure, these fluctuations are associated with perturbed currents parallel to the equilibrium magnetic field lines. A model for these magnetohydrodynamic modes in a low-β, three-dimensional stellarator equilibria has been developed. A set of helical current filaments are constrained to mimic the structure of magnetic field lines on rational surfaces derived from three-dimensional (3D) equilibrium reconstructions. Transformation to straight field line coordinates then allows fitting of the poloidal magnetic sensor data to a single harmonic function, which fixes the modeled toroidal mode structure via the field line flow geometry. The developed procedure accurately captures phase and amplitude variation for m/n = 3/2, 3/1, and 4/1 modes in the 3D equilibria of the compact toroidal hybrid experiment.
Thermal transport in organic semiconductors
Authors: Wang Xinyu , Wang Weitao , Yang Chao , Han Dan , Fan Hongzhao , Zhang Jingchao
Published: November 2021

Organic semiconductors have attracted worldwide attention and have shown great potential in emerging organic electronic devices due to their excellent properties. Advances in miniaturization and integration of organic electronic devices require understanding and tuning thermal transport capabilities of organic semiconductors to achieve desired results. In this Perspective, recent advances in the thermal transport of organic semiconductors are summarized and discussed. First, the characteristics and applications of organic semiconductors are systematically introduced. In addition, thermal conductivities of organic semiconductors and interfacial thermal conductances of different organic semiconductor-based interfaces are analyzed and summarized, respectively. Moreover, thermoelectric applications of organic semiconductors are discussed. Finally, this Perspective concludes with a summary of the current research and an outlook to guide future research in the field of organic semiconductors.
Ferroelectric and magnetic properties in ε-Fe2O3 epitaxial film
Authors: Hamasaki Yosuke , Yasui Shintaro , Katayama Tsukasa , Kiguchi Takanori , Sawai Shinya , Itoh Mitsuru
Published: November 2021

The phase stability, ferroelectricity, and magnetism of highly crystalline epitaxial ε-Fe2O3 films deposited on SrTiO3(111) substrates are reported. Temperature-dependent x-ray diffraction measurements revealed that α-Fe2O3 appeared as a secondary phase after samples were annealed up to 1000 °C. A clear saturated and opened polarization–electric field hysteresis loop with the remnant polarization ∼2.6 μC cm−2 and coercive electric field ∼100 kV cm−1 was obtained at room temperature using a conventional ferroelectric measurement technique. The magnetic phase transition was observed at 155 K. Magnetization–magnetic field measurements revealed that magnetic softening via the phase transition accompanied a reduction in the coercive field from 10 to 6.8 kOe, which is smaller than the coercive field reduction previously observed for ε-Fe2O3 nanoparticles.
Understanding the bonding mechanisms of organic molecules deposited on graphene for biosensing applications
Authors: Legge Elizabeth J. , Ali Muhammad M. , Abbasi Hina Y. , Reed Benjamen P. , Brennan Barry , Matjačić Lidija , Tehrani Zari , Stolojan Vlad , Silva S. Ravi P. , Guy Owen J. , Pollard Andrew J.
Published: November 2021

Graphene is an ideal material for biosensors due to the large surface area for multiple bonding sites, the high electrical conductivity allowing for high sensitivity, and the high tensile strength providing durability in fabricated sensor devices. For graphene to be successful as a biosensing platform, selectivity must be achieved through functionalization with specific chemical groups. However, the device performance and sensor sensitivity must still be maintained after functionalization, which can be challenging. We compare phenyl amine and 1,5-diaminonaphthalene functionalization methods for chemical vapor deposition grown graphene, both used to obtain graphene modified with amine groups—which is required for surface attachment of highly selective antibody bio-receptors. Through atomic force microscopy (AFM), Raman spectroscopy, and time-of-flight secondary ion mass spectrometry imaging of co-located areas, the chemistry, thickness, and coverage of the functional groups bound to the graphene surface have been comprehensively analyzed. We demonstrate the modification of functionalized graphene using AFM, which unexpectedly suggests the removal of covalently bonded functional groups, resulting in a “recovered” graphene structure with reduced disorder, confirmed with Raman spectroscopy. This removal explains the decrease in the ID/IG ratio observed in Raman spectra from other studies on functionalized graphene after mechanical strain or a chemical reaction and reveals the possibility of reverting to the non-functionalized graphene structure. Through this study, preferred functionalization processes are recommended to maintain the performance properties of graphene as a biosensor.
New findings in vorticity dynamics of turbulent buoyant plumes
Authors: Chen Chang Hsin , Bhaganagar Kiran
Published: November 2021

The vorticity dynamics of turbulent, buoyant, and pure plumes released into the quiescent ambience has been investigated using large-eddy simulations with plume Reynolds number in the range of 6 × 107 to 108. The plume is generated by a circular heat source and sustained by buoyancy forcings generated by heating. As the starting plume rises vertically, it expands radially, entraining ambient fluid into the plume and two distinct stages of evolution are evident. During stage one (initial stage), in the near-source region the plume is accelerating characterized by developing turbulence. During the next stage (mixing stage), the plume is significantly altered by turbulence resulting in significant entrainment and expansion in the radial direction. As turbulent intensities decay during the mixing stage, the enstrophy decays in an exponential manner with height with an exponent of −7/4. The turbulent kinetic energy budget analysis reveals—baroclinic torque, stretching, and compression—as the three dominant mechanisms for the plume growth. The probability distribution function (PDF) of vorticity shows that vorticity is mainly aligned along the transverse direction near the source and slowly reaches to a quasi-isotropy state downstream. Turbulence spectra demonstrate the presence of a buoyancy-regime with a −3 spectral slope. The PDF of vorticity further shows extreme dominance of the strain rate rather than rotation within the plume. Consistent with studies in the literature, the vorticity fluctuations align with the intermediate eigen-vector of strain-rate tensor.
Improved minority carrier lifetime in p-type GaN segments prepared by vacancy-guided redistribution of Mg
Authors: Shima K. , Tanaka R. , Takashima S. , Ueno K. , Edo M. , Kojima K. , Uedono A. , Ishibashi S. , Chichibu S. F.
Published: November 2021

To accelerate the development of GaN power devices, reproducible fabrication of p-type GaN (p-GaN) segments by ion-implantation (I/I) that enables selective-area doping is preferred. In this Letter, the results of time-resolved photoluminescence (PL) and spatially resolved cathodoluminescence (CL) measurements on p-GaN fabricated by I/I are presented. The p-GaN samples of a 220-nm-deep box-shaped Mg concentration profile ([Mg] = 3×1018 cm−3) were fabricated by sequential I/I of Mg and N followed by atmospheric-pressure post-implantation annealing (PIA). During PIA, Mg redistribution was guided by N-I/I-induced vacancies. The intensities of PL peaks originating from Mg acceptors were increased by increasing the PIA temperature (Ta), indicating progressive activation of Mg and simultaneous decrease in the concentration of nonradiative recombination centers (NRCs). As a result, a record-long room-temperature PL lifetime for the near-band edge emission of Ga-polar Mg-implanted p-GaN (1.4 ps) was obtained when Ta = 1300 °C. Because the species of major vacancy-type defects in the present sample was determined as vacancy clusters comprised of few Ga-vacancies (VGa) and N-vacancies (VN) such as (VGaVN)2–3, the NRC concentration is roughly estimated at around 1017 cm−3 provided that (VGaVN)2–3 are major NRCs with the electron-capture-coefficient of 7×10−6 cm3 s−1. Cross-sectional CL linescan images revealed certain activation of Mg from the surface to the leading edge of the box-shaped [Mg] profile, while NRCs remained at the depths right below the box-shaped profile. The results support advantages of using the vacancy-guided Mg redistribution technique for controlling the activated [Mg] profile and realizing p-type Ga-polar GaN:Mg segments by I/I.
Topology and transport in generalized helical flows
Authors: Chakraborty Priyam , Roy Arnab , Chakraborty Suman
Published: November 2021

Pure helical or screw flow presents a unique combination of zero net advection, alignment of vorticity dissipation with vorticity field, and maximal helicity. Helicity is a measure of knottedness in a flow structure as manifested in terms of a net imbalance between right and left handed helical motion. Topology, which is intrinsic to helicity, provides a geometric perspective to vortex reconnection in helical flow. However, the topological evolution and the resulting transport in helical flows remain unclear. Here, we investigate the evolution of isosurfaces associated with the Galilean invariant Q-criterion in generalized models of helical flow. While we categorize the stagnation points with Δ-criterion, the Gaussian curvature shows that the creation and annihilation of these points occur in pairs for specific instances of helical flow. The contours of finite-time Lyapunov exponent reveal the fluidic mixing due to the strain and shear transport barriers. These findings have far-reaching implications in diverse fields, ranging from classical turbulence in superfluid helium to dynamos in growing magnetic field. The present article sheds insights into these applications.
Influence of near threshold energy electron irradiation on the thermal conductivity of IIa diamond
Authors: Guo Zhijian , Zhu Xinmiao , Wang Kaiyue , Zhang Yufei , Tian Yuming , Wang Hongxing
Published: November 2021

Diamond has the advantages of excellent thermal conductivity, and it is the material with the largest thermal conductivity currently known, which makes it the ideal heat sink. However, in the process of processing or as a heat sink for electronic devices, diamond is often exposed to a high-frequency, high-voltage, high-temperature, and high-energy environment, which has greatly affected the performance of diamonds. Therefore, in this paper, it systematically explores the influence of near threshold energy electron irradiation and annealing at different temperatures on the thermal conductivity of IIa diamond by the method of laser excited Raman spectroscopy. The results show that before 900 °C annealing, the main factor affecting thermal conductivity in IIa diamond is the large number of vacancy defects caused by near threshold energy electron irradiation. The irradiation and annealing both affect the thermal conductivity by controlling the vacancy defects concentration.
Understanding the role of structural distortions on the transport properties of Ar ion irradiated SrTiO3 thin films: X-ray absorption investigation
Authors: Bhogra Anuradha , Masarrat Anha , Hasina Dilruba , Kumar Vishnu , Meena Ramcharan , Kumar Ashish , Som Tapobrata , Dong Chung-Li , Chen Chi-Liang , Kandasami Asokan
Published: November 2021

We report the evolution of structural distortions on the pulsed laser deposited SrTiO3 (STO) thin films irradiated by 1 MeV Ar ion beam and their response in the electrical and thermoelectric properties correlated with their electronic structures. The structural studies reveal a modification in the crystalline nature resulting in the synergistic enhancement of resistivity and the Seebeck coefficient due to ion irradiation-induced oxygen vacancies and augment the power factor to ∼17 μW m−1K−2, which is 2.5 times higher than the pristine STO. An in-depth analysis of the conduction mechanism using various theoretical models implies the role of band conduction and Mott-variable range hopping. Further, the changes in the local electronic structures are reflected in the variation in the Ti–O bond length and the density of unoccupied states that alter the spectral intensities and chemical shifts and are responsible for the observed enhancement in the thermoelectric properties. The above results indicate the significance of the ion beams to tune the electrical and thermoelectric properties.
An optimized Eulerian–Lagrangian method for two-phase flow with coarse particles: Implementation in open-source field operation and manipulation, verification, and validation
Authors: Zhang Yan , Lu Xiao-Bing , Zhang Xu-Hui
Published: November 2021

The solid–liquid two-phase flow with coarse particles is ubiquitous in natural phenomena and engineering practice, which is characterized by coarse particles, high particle concentration, and large particle size distribution. In this work, the numerical models describing two-phase flows are reviewed, which given that the Eulerian–Lagrangian method is applicable in this work. Then, some modified models are proposed for the situation where the conventional Eulerian–Lagrangian method is not applicable to deal with coarse particles. The continuous phase equations of liquid are solved based on the finite volume method. The pressure implicit with splitting of operators algorithm for solving the Navier–Stokes (N–S) equations of the pseudo-single-phase flow, considering phase fraction and momentum exchange source term, is proposed. The discrete coarse particle is tracked in the Lagrangian method. A virtual mass distribution function is proposed for calculating coarse particle volume fraction. A weighted function method relating to the particle size is given for the interpolation between the Eulerian and Lagrangian fields. The barycentric coordinates are introduced into the particle localization. All the modified models are algorithmically implanted in the open-source field operation and manipulation (OpenFOAM) as a new solver named coarse discrete particle method FOAM (CoarseDPMFoam). Subsequently, the applicability of the numerical simulation method is verified by some typical test cases. The proposed numerical simulation method provides new ideas and methods for the mechanism investigation and engineering application of the two-phase flow with coarse particles.
Conical intersection seams in spin–orbit coupled systems with an even number of electrons: A numerical study based on neural network fit surfaces
Authors: Wang Yuchen , Yarkony David R.
Published: November 2021

In this work, we consider the existence and topography of seams of conical intersections (CIs) for two key singlet–triplet systems, including a uniformly scaled spin–orbit interaction. The basic one triplet and one singlet state system denoted as (S0,T1) and the two singlets and one triplet system denoted as (S0,S1,T1) are treated. Essential to this analysis are realistic electronic structure data taken from a recently reported neural network fit for the 1,21A and 13A states of NH3, including Hsf (spin-free) and Hso (spin–orbit) surfaces derived from high quality ab initio wavefunctions. Three types of seams for the (S0,S1,T1) system are reported, which depend on the choice of the electronic Hamiltonian, He. The nonrelativistic CI seam [He = Hsf, (S0,S1)], the energy minimized nonrelativistic singlet–triplet intersection seam [He = Hsf, (S0,T1)], and the fully relativistic seam in the spin-diabatic representation (He = Htot = Hsf + Hso) are reported as functions of R(N–H). The derivative couplings are computed using He = Htot and Hsf from the fit data. The line integral of the derivative coupling is employed to juxtapose the geometric phase in the relativistic, He = Htot, and nonrelativistic, He = Hsf, cases. It is found for the (S0,T1) system that there is no CI in the spin-adiabatic representation, while for the (S0,S1,T1) system, CI can only be formed for two pairs of spin-adiabatic electronic states. The geometric phase effect thus needs to be handled with care when it comes to spin-nonconserving dynamics simulations.
Formulation of bed shear stress for computing bed-load transport rate in vegetated flows
Authors: Lu Yesheng , Cheng Nian-Sheng , Wei Maoxing
Published: November 2021

Difficulties are often encountered in estimating the bed shear stress in vegetated flows over a sediment bed due to complex interactions of the flow, sediment, and vegetation. Without involving any empirical partition of the bed friction and vegetation resistance, this study presents an analytical approach to evaluate the bed shear stress in the presence of vegetation in light of the phenomenological theory of turbulence. Then, the bed-load transport rate in vegetated flows is computed, with a result that agrees well with the bed-load transport formula developed for unvegetated flows. In addition, it is also shown that the present method is applicable not only to uniformly distributed vegetation but also to vegetation patches. However, further efforts are needed to extend the present model for flexible and submerged vegetation conditions.
Performance of metal-semiconductor field effect transistors on mist chemical-vapor-deposition grown ZnO channels with intentionally oxidized AgOx Schottky contact gates
Authors: Onyema Chikezie C. , Reeves Roger J. , Allen Martin W.
Published: November 2021

Metal-semiconductor field-effect transistors (MESFETs) were fabricated on ZnO thin films grown via mist-chemical vapor deposition (mist-CVD), a solution-based, highly scalable, non-vacuum technique. High-performance MESFETs were achieved by using in situ intentionally oxidized AgOx Schottky contact (SC) gates with large effective barrier heights (1.13−1.18 eV) and rectification ratios (at ±2 V) of >107. The device properties of the resulting MESFETS were investigated as a function of channel thickness, gate length, and temperature (T = 25–130 °C) with the best performing devices characterized by on/off current ratios >107, channel mobilities of 5.7 cm2V−1 s−1, and sub-threshold slopes of ∼100 mV/decade at room temperature. Reliable operation was maintained up to 130 °C with only a gradual increase in off current due to increased thermionic emission across the SC gate. These results demonstrate the potential of using the combination of mist-CVD ZnO channels and AgOx SC gates to produce low-cost, low operating voltage, transparent thin film transistors. The key physical processes are a significant increase in Schottky barrier height and the passivation of oxygen vacancies at the gate–channel interface due to the presence of reactive oxygen species during the deposition of the AgOx gate.
On the mechanisms leading to ordered nanoparticles deposition during single bubble nucleate pool boiling regime
Authors: Kangude Prasad , Srivastava Atul
Published: November 2021

The present study investigates the underlying mechanisms of nanoparticle deposition during nucleate pool boiling on plain hydrophobic surfaces. Single bubble pool boiling experiments with water and two concentrations of SiO2-water nanofluids have been conducted under saturated conditions. Indium tin oxide-coated sapphire has been employed as the substrate surface. Infrared (IR) thermography has been used to map the temperature and heat flux distributions underneath the vapor bubble to identify the mechanisms responsible for imparting an orderly pattern to nanoparticle deposition. Optical characterization of nanoparticle-deposited substrates showed a distinct circular porous structure of the deposited nanoparticles at the nucleation site and almost negligible deposition away from it for both the nanofluid concentrations. Temperature and heat flux contour plots indicated toward the ceasing of microlayers for water-based experiments and existence of microlayers for nanofluids. The observed nature of the nanoparticle deposited layer has been attributed to the prevalent bubble base evaporation mechanism. Interdependence between the bubble base evaporation mechanism and nanoparticle deposition has been discussed. An intriguing feature of the nanoparticle deposited structure in the form of a thin peripheral ring was identified, wherein larger micrometer-sized particles were found to be deposited along the ring while the smaller-sized nanoparticles were found in the inner core region. Plausible explanation(s) for the mechanisms associated with the observed size distribution of nanoparticles over the deposited structure have been provided. The IR thermography-based temperature data have been used for heat transfer partitioning. The analysis showed that the overall heat transfer coefficient decreases with nanofluids as compared to water as the working fluid.
Dynamics near a conical intersection—A diabolical compromise for the approximations of ab initio multiple spawning
Authors: Ibele Lea M. , Curchod Basile F. E.
Published: November 2021

Full multiple spawning (FMS) offers an exciting framework for the development of strategies to simulate the excited-state dynamics of molecular systems. FMS proposes to depict the dynamics of nuclear wavepackets by using a growing set of traveling multidimensional Gaussian functions called trajectory basis functions (TBFs). Perhaps the most recognized method emanating from FMS is the so-called ab initio multiple spawning (AIMS). In AIMS, the couplings between TBFs—in principle exact in FMS—are approximated to allow for the on-the-fly evaluation of required electronic-structure quantities. In addition, AIMS proposes to neglect the so-called second-order nonadiabatic couplings and the diagonal Born–Oppenheimer corrections. While AIMS has been applied successfully to simulate the nonadiabatic dynamics of numerous complex molecules, the direct influence of these missing or approximated terms on the nonadiabatic dynamics when approaching and crossing a conical intersection remains unknown to date. It is also unclear how AIMS could incorporate geometric-phase effects in the vicinity of a conical intersection. In this work, we assess the performance of AIMS in describing the nonadiabatic dynamics through a conical intersection for three two-dimensional, two-state systems that mimic the excited-state dynamics of bis(methylene)adamantyl, butatriene cation, and pyrazine. The population traces and nuclear density dynamics are compared with numerically exact quantum dynamics and trajectory surface hopping results. We find that AIMS offers a qualitatively correct description of the dynamics through a conical intersection for the three model systems. However, any attempt at improving the AIMS results by accounting for the originally neglected second-order nonadiabatic contributions appears to be stymied by the hermiticity requirement of the AIMS Hamiltonian and the independent first-generation approximation.
Effect of elastic instability on mobilization of capillary entrapments
Authors: Shakeri Pegah , Jung Michael , Seemann Ralf
Published: November 2021

The flow of viscoelastic polymer solutions and their use as displacing agents in porous media are important for industrial applications, such as enhanced oil recovery and soil remediation. The complexity of flow and high elasticity of conventionally used viscoelastic polymer solutions can lead to purely elastic instability in porous media. In this study, we investigate the impact of this instability on displacing capillary entrapments at low Reynolds numbers using a microfluidic approach. Our unique design consists of a single-capillary entrapment connected to two symmetric serpentine channels. This design excludes the effect of viscous forces and enables a direct focus on displacement processes driven solely by elastic forces. After the onset of purely elastic instability, an unstable base flow is observed in the serpentine channels. We discuss that the pressure fluctuations caused by this unstable flow create an instantaneous non-equilibrium state between the two ends of the capillary entrapment. This provides the driving pressure to overcome the capillary threshold pressure and eventually displace the entrapped oil. In our geometry, we observe that the displacement coincides with the emergence of a fully developed elastic turbulent state.
Experimental study of a 100-W all-fibre amplifier operating near 980 nm
Authors: Chen M. , Du H. , Cao J. , Liu A. , Pan Zh. , Huang Zh. , Chen J.
Published: November 2021

A 100-W all-fibre amplifier operating near 980 nm is demonstrated with a double-clad Yb-doped fibre (DCYF) having a 60/125-μm core/cladding diameter. By preliminarily optimising the length of DCYF (about 1.4 m), a total output power of about 113.4 W is obtained with 9-W seed light, the peak-to-peak suppression of 1030-nm ASE being about 21.5 dB. The effect of active fibre length is studied using the experimental setup. With the help of spectrum integration, it is found that while the total output power decreases, the output power around 980 nm is enlarged with the active fibre (i.e., DCYF) further shortened to 1.2 m, which is due to better suppression of 1030-nm ASE. It means that the effect of 1030-nm ASE cannot be simply neglected when its peak-to-peak suppression is lower than 30 dB. The effect of seed power on the output properties of the amplifier is also studied experimentally. It is found that a stronger seed power is beneficial to the 1030-nm ASE suppression and slope efficiency improvement. Then, with the 1.2-m DCYF and 14-W seed power, the largest output signal power around 980 nm (estimated about 108.2 W) is eventually obtained and the peak-to-peak suppression of 1030-nm ASE is more than 33 dB at the maximum output power. The pertinent results can provide significant guidance for the design and study of a 980-nm laser and other sorts of three-level fibre laser.
Optical absorption in a waveguide based on an n-type AlGaAs heterostructure
Authors: Bobretsova Yu.K. , Veselov D.A. , Klimov A.A. , Bakhvalov K.V. , Shamakhov V.V. , Slipchenko S.O. , Andryushkin V.V. , Pikhtin N.A.
Published: November 2021

Free carrier absorption of optical radiation in layers of an AlGaAs/GaAs heterostructure is studied by the method of probe radiation coupling in order to determine the absorption cross section parameter in the AlGaAs material with a high (22%) aluminium concentration. For this purpose, we have fabricated special samples based on AlGaAs/GaAs heterostructures simulating an n-type-doped laser waveguide with carrier concentrations in the range 5 × 1016− 3 × 1017cm−3. The doping profile and the composition and thickness of layers are measured and the temperature and spectral dependences of the absorption coefficient are studied. It is shown that an increase in temperature and in the probe wavelength leads to an increase in the absorption in the heterostructure layers.
Investigation of spatial and temporal characteristics of turbulent-distorted laser radiation during its dynamic phase correction in an adaptive optical system
Authors: Belousov V.N. , Bogachev V.A. , Volkov M.V. , Garanin S.G. , Kudryashov A.V. , Nikitin A.N. , Rukosuev A.L. , Starikov F.A. , Sheldakova Yu.V. , Shnyagin R.A.
Published: November 2021

We report the results of the analysis of experiments on dynamic phase correction of laser radiation distorted by a turbulent airflow in an adaptive optical system (AOS) with a Shack–Hartmann wavefront sensor (WFS). A field-programmable gate array is used as the main AOS control element, which provides a closed loop AOS bandwidth of up to 2000 Hz. The WFS is used to estimate the characteristic bandwidth of the generated turbulence ν
turb. Changes in the spatial and temporal spectra of the laser radiation phase, as well as the quality of the beam during its dynamic phase correction at various AOS frequencies, are analysed. It is shown experimentally and by calculation that to ensure a high efficiency of the wavefront correction, the AOS frequency should be at least 20 times higher than ν
turb.
Regime of beatings of counterpropagating waves in a Zeeman ring laser in a strong magnet field
Authors: Kudryavtsev A.S. , Lariontsev E.G. , Saveliev I.I.
Published: November 2021

We have theoretically and experimentally studied the regime of beatings of counterpropagating waves in a Zeeman ring laser under the action of strong fields of ring permanent magnets on the active medium. We have for the first time calculated and measured the dependences of the frequency bias and the intensity of counterpropagating waves of such a laser on the lasing frequency detuning relative to the frequency of the gain line centre. We have revealed some features in the dependence of the frequency bias on the magnetic field strength, associated with the nonlinearity of the active medium polarisability in strong inhomogeneous magnetic fields.
High-frequency electric field intensity sensor based on double-slot waveguides filled with electro-optical polymer
Authors: Goncharenko I.A. , Ryabtsev V.N.
Published: November 2021

We consider the structure of a high-frequency external electric field sensor based on microring resonators using waveguides with two horizontal or vertical slots filled with an electro-optical polymer. The method of lines is used to calculate the propagation constants and mode field distributions of such waveguides. It is shown that double-slot waveguides filled with an electro-optical polymer exhibit higher optical radiation intensity in the slot region compared to single-slot waveguides, which makes it possible to increase the sensor sensitivity. The distances between the slots and the values of their widths at which a maximum sensor sensitivity is achieved are determined. The sensor allows alternating electric fields with frequencies up to 10 GHz to be measured in the range of 100−16 × 106 V m−1 with an accuracy of 150 V m−1.
An integrative transcriptional logic model of hepatic insulin resistance
Authors: Kitamoto Takumi , Kuo Taiyi , Okabe Atsushi , Kaneda Atsushi , Accili Domenico
Published: November 2021

Significance

The liver is a source of excess lipid, atherogenic lipoproteins, and glucose in patients with type 2 diabetes. These factors predispose to micro- and macrovascular complications. The underlying pathophysiology is not well understood, and mechanistic insight into it may provide better tools to prevent, treat, and reverse the disease. Here, we propose an alternative explanation for this pathophysiologic conundrum by illustrating a transcriptional “logic” underlying the regulation of different classes of genes. These findings can be interpreted to provide an integrated stepwise model for the coexistence of lipid and glucose abnormalities in hepatic insulin resistance.
Ultrafast four-dimensional imaging of cardiac mechanical wave propagation with sparse optoacoustic sensing
Authors: Özsoy Çağla , Özbek Ali , Reiss Michael , Deán-Ben Xosé Luís , Razansky Daniel
Published: November 2021

Significance

Propagation of electromechanical waves in excitable heart muscles follows complex spatiotemporal patterns holding the key to understanding life-threatening arrhythmias. Despite recent progress, there is a lack of cardiac imaging methods capable of transmural visualization of fast electromechanical phenomena across the beating heart. Here we introduce a sparse optoacoustic sensing technique for ultrafast four-dimensional imaging of cardiac mechanical wave propagation in the entire beating murine heart with high contrast and sub-millisecond temporal resolution. We extract accurate dispersion and phase velocity maps of the cardiac waves and reveal vortex-like patterns associated with mechanical phase singularities that occur during arrhythmic events induced via ventricular stimulation. Our cardiac mapping approach is a bold step toward deciphering the complex mechanisms underlying cardiac arrhythmias.
Cognitive deficits and impaired hippocampal long-term potentiation in K
ATP
-induced DEND syndrome
Authors: Yahil Shaul , Wozniak David F. , Yan Zihan , Mennerick Steven , Remedi Maria S.
Published: November 2021

Significance

Gain-of-function (GOF) mutations in the ATP-sensitive potassium (K
ATP
) channel cause neonatal diabetes, with some individuals exhibiting developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome. In this study, we uncover the direct effects of neuronal expression of K
ATP
-GOF mutations, and not diabetes per se, on the neurological features of DEND. Our results show a close link between neuronal K
ATP
-GOF expression and cognitive dysfunction in DEND and reveal that antidiabetic sulfonylureas, which successfully treat diabetes, mitigate some sensorimotor problems but not cognitive deficits. These results have critical implications for humans, revealing the need for novel drugs to treat learning and memory deficits not only for K
ATP
-induced DEND but also for other pathologies arising from altered ion channels in the brain.
Furin cleavage of the SARS-CoV-2 spike is modulated by
O
-glycosylation
Authors: Zhang Liping , Mann Matthew , Syed Zulfeqhar A. , Reynolds Hayley M. , Tian E. , Samara Nadine L. , Zeldin Darryl C. , Tabak Lawrence A. , Ten Hagen Kelly G.
Published: November 2021

Significance

The novel SARS-CoV-2 coronavirus that is responsible for the global pandemic contains a unique insertion of four amino acids within the spike protein (S). Furin cleavage at this novel insertion site has been shown to increase pseudoviral infectivity and syncytia formation. Here we show that
O
-glycosylation by certain GALNT family members decreases furin cleavage of S and decreases syncytia formation. Moreover, we show that P681 mutations found in the highly transmissible alpha and delta variants decrease
O
-glycosylation, which increases furin cleavage and syncytia formation. Our results highlight how host-mediated
O
-glycosylation may influence viral infectivity and how mutations in the recent alpha and delta variants may circumvent this.
Shared neural codes for visual and semantic information about familiar faces in a common representational space
Authors: Visconti di Oleggio Castello Matteo , Haxby James V. , Gobbini M. Ida
Published: November 2021

Significance

Our brain processes faces of close others differently than faces of visually familiar individuals. While both types of faces activate similar visual areas, faces of close others activate areas involved in processing social and semantic information. Here, we used between-subject linear classifiers trained on hyperaligned brain data to investigate the neural code for visual and semantic information about familiar others. The identity of both visually and personally familiar faces could be decoded across participants from brain activity in visual areas. Instead, only the identity of personally familiar faces could be decoded in areas involved in social cognition. Our results suggest that individually distinctive information associated with familiar faces is embedded in a neural code that is shared across brains.
Cell density, alignment, and orientation correlate with C-signal–dependent gene expression during
Myxococcus xanthus
development
Authors: Hoang Y , Franklin Joshua L. , Dufour Yann S. , Kroos Lee
Published: November 2021

Significance

Pattern formation is foundational to development of multicellular organisms. To investigate patterning in bacteria during formation of
Myxococcus xanthus
fruiting bodies, cellular arrangement, morphology, and gene expression driven by C-signaling were quantified using high-resolution microscopy. How short-range C-signaling controls gene expression governing rod-to-spore differentiation within multicellular mounds has been unclear. The results support a model in which cell density, rod neighbor alignment, and rod tangential orientation affect C-signaling efficiency to pattern gene expression and spore maturation. Other bacterial biofilms may likewise be patterned by short-range signaling that captures local cellular arrangement and dynamical interactions, which could be exploited to manipulate biofilm development. Our results provide fundamental insights into spatiotemporal patterning by short-range signaling, which is relevant to animal development.
Direct imaging of intraflagellar-transport turnarounds reveals that motors detach, diffuse, and reattach to opposite-direction trains
Authors: Zhang Zhiqing , Danné Noémie , Meddens Bonno , Heller Iddo , Peterman Erwin J. G.
Published: November 2021

Significance

Primary cilia are important organelles that exist in almost all eukaryotic cells. Intraflagellar transport (IFT) is a motor-protein–driven bidirectional intracellular transport mechanism in cilia. Previous studies have shown that motors in
Caenorhabditis elegans
chemosensory cilia undergo rapid turnarounds to effectively work together in driving orderly IFT. The mechanism of motor turnarounds has, however, remained unclear. Here, using a combination of advanced fluorescence imaging and single-molecule analysis, we directly show that the individual turnarounds are due to motors switching between opposite-direction IFT trains. Furthermore, we show that switching events consist of motors detaching from a train, diffusing to another one followed by attachment. This directly demonstrates that motors switch trains by diffusion, which clarifies the mechanism of motor turnarounds.