bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous communication in beginning signers, Part I: Temporal characteristics of speech
Authors: Whitehead Robert L. , Schiavetti Nicholas , Metz Dale Evan , Farrell Thomas
Published: July 2002

Simultaneous communication combines spoken English with manual representations of English words by signs and fingerspelling. The purpose of this study was to investigate temporal characteristics of speech produced during simultaneous communication (SC) by beginning signers. Audio recordings of stimulus words embedded in sentences produced with speech only and SC were made by 12 students during the first and last weeks of a 15 week introductory sign language course. Temporal measures included: (a) sentence duration; (b) experimental word duration; (c) vowel duration of the experimental word; (d) interword interval before the experimental word; and (e) interword interval after the experimental word. Results indicated significant temporal differences between speech-only and SC conditions at both the beginning and the end of the sign language course. In addition, a pattern emerged in which beginning signers first signed between words in SC, thereby extending interword intervals, and then, at the end of the sign language course, shifted toward attempting to simultaneously sign while speaking the words, thereby elongating segmental temporal characteristics such as vowel duration. These results are consistent with previous findings regarding the effect of simultaneous communication on temporal characteristics of speech with experienced signers.
Rethinking the basics of declination
Authors: Xu Yi
Published: July 2002

Declination, the tendency of fundamental frequency to gradually fall over the course of an utterance, has for a long time been treated as if it were a universal principle of speech intonation. Most intonation models adopt declination as a baseline upon which more local F0 patterns reside. A reexamination of the literature related to declination finds, however, that the existence of declination as an independent F0-determining mechanism is far from being firmly established. Instead, some recent as well as earlier studies are found to provide evidence that various linguistic factors may be responsible for generating different local as well as global patterns of intonation, which, taken as a whole, may sometimes give the appearance of declination. These factors include sentence focus, topic initiation, word stress, and lexical tone. When these factors happen to be neutralized, virtually flat F0 contours may occur, as have been observed in some tone languages. Furthermore, the commonly assumed declination rate is found to well exceed the possible rates of pitch decline due to global physiological limitations. It is concluded that, rather than being a basic principle of intonation, declination is more likely to be an artifact of various linguistic factors plus certain local physiological constraints.
Constraints on syllable structure in speech
Authors: Jones Jeffery A. , Purdy Kimberly , Munhall Kevin G.
Published: July 2002

This paper presents kinematic data and a statistical analysis of the MRC Psycholinguistic Database in a study of patterns of syllable coda structure in English bisyllables. X-ray microbeam and OPTOTRAK data were used to study spontaneous errors in rapid speech. Subjects repeated real-word and nonsense bisyllables at increasing speaking rates. All subjects made errors that harmonized the place of articulation of the codas at faster speaking rates. Errors were determined by kinematic changes in the tongue and lip gestures. Analysis of the MRC Psycholinguistic Database revealed that coda harmonies occur statistically more frequently than chance in English even when the statistical incidence of segments are taken into account. The experimental evidence is discussed in terms of production constraints on syllable production. The influence of stress pattern, manner, and place of articulation are explored. [Work supported by NIH-NIDCD Grant No. DC-00594 and NSERC.]
Voice F0 responses to feedback pitch are not affected by speed of stimulus onset
Authors: Burnett Theresa A. , Kiran Swathi , Larson Charles R.
Published: July 2002

Voice F0 appears flexibly controlled by interactions between voluntary mechanisms, memory, and auditory feedback. Previous studies have shown that voice F0 is changed following an abrupt shift in feedback pitch [Elman, 1981; Kawahara, 1994; Larson et al., 1995]. In order to establish that this response is due to the pitch of the feedback shift rather than its onset speed, an experiment was conducted in which voice feedback pitch heard loudly through headphones was slowly or quickly decreased to 100 cents lower than the steady voice F0 produced by the subjects. Subjects were instructed to maintain steady F0 production regardless of any feedback changes they might hear. Both slow and fast ramping pitch shift stimuli (PSS) generally elicited opposing responses characterized by a rising voice F0 which mirrored the slope of the lowering PSS ramp. Accordingly, response latency and time of peak response were inversely related to the slope of the PSS ramp; the lower the slope, the later the response latency and peak. Peak response magnitude was not affected by ramp speed. These results suggest that the auditory–vocal system continuously monitors auditory feedback and adjusts vocal output so as to reduce the difference between it and a reference signal.
The enormous acoustic nonlinearity of air-contained sand sediments
Authors: Donskoy Dimitri M. , Sutin Alexander
Published: July 2002

The nonlinear acoustic properties of sediments have been studied using a novel experimental approach. A small amount (10–100 cm3) of sediments is suspended in a water column in a sound transparent vessel. The vessel is placed inside an experimental tank and exposed to harmonic acoustic pressure. Nonlinearity of sediments causes the generation of higher harmonics which are radiated into the surrounding water and measured with a hydrophone. The nonlinear response for various frequencies (0.1–10 kHz) of the excitation is studied varying both the grain-size distribution of the sediment and the amount of trapped air. A very significant level of nonlinear distortion is observed even for a relatively low amplitude of the excitation signal (under 200 Pa). In some cases (coarse sand with a 0.01–0.03 gas void friction) up to 20 harmonics are observed, with the second harmonic attaining 30% (−10 dB) of the fundamental. Such a high level is 120 dB greater than the estimated amplitude of the second harmonic generated by the same volume of pure water and more than 40 dB greater than could be generated by water having the same gas void friction. The theoretical model of such a considerable nonlinear behavior based on the interaction of grains in the presence of gas voids is discussed. [Work supported by ONR.]
Three-dimensional localizations of vocalizing blue whales
Authors: D’Spain Gerald L. , Thode Aaron M. , Kuperman William A.
Published: July 2002

During a recent experiment in the Southern California Bight region, recordings of vocalizing blue whales were made simultaneously by a vertical line array of 48 hydrophones and freely drifting, standard Navy sonobuoys. Vector acoustic intensity techniques are applied to the ‘‘DIFAR’’ sonobuoy data to determine azimuth versus time for two individual animals vocalizing in turn. Once the azimuths are determined, matched-field processing with a 2-D normal-mode code is applied to the vertical hydrophone array data to determine the animals’ position in range and depth. These processing techniques used with the data from these two sensor systems permit investigations to be made of diving behavior, vocalization source levels, and calling interactions. [Work supported by ONR, Codes 341BST and 321OA.]
Acoustical localization of dolphins in shallow water
Authors: Aubauer Roland , Lammers Marc O. , Au Whitlow W. L.
Published: July 2002

Previous attempts at localization of cetaceans have generally used multiple hydrophone arrays and multichannel recording systems. In this paper a low-budget localization technique using only one hydrophone will be described. The time delays of the signals traveling on the surface and bottom reflection paths to the hydrophone, relative to the direct signal, are used to calculate the distance and the depth of a phonating animal. Only two additional measures, the depth of the bottom and hydrophone, have to be taken. The method requires relatively shallow waters and a flat ground surface. The received signals are digitized directly into a laptop computer via a PCMCIA A/D converter card with a sampling rate of 260 ksamples/s. Hawaiian spinner dolphins (Stenella langirostris) were localized by echolocation and burst pulse click trains over different bottom substrates. The method is most valuable for examining source levels of dolphin clicks in the wild and could lead to a better understanding of the nature and use of click trains by dolphins. [Work supported by Deutsche Forschungsgemeinschaft and Office of Naval Research.]
Multiple scattering in waveguides with rough interfaces
Authors: Berman David H.
Published: July 2002

Schmidt and Kuperman [J. Acoust. Soc. Am. 97, 2199–2209 (1995)] show that it is possible to treat multiple scattering in media with elastic and fluid layers separated by rough interfaces. Their work, based on a ‘‘smoothing’’ approximation, shows that the coherent (mean) field obeys certain effective boundary conditions. These boundary conditions account for some of the multiple interactions between interfaces. Kuperman and Schmidt also compute the second moment of the scattered field. However, their computations of the second moment include multiple scattering only insofar as the fields which are scattered are the mean fields which depend on the effective boundary conditions. Recent work [Sanchez-Gil et al., Phys. Rev. B 50, 15353–15368] shows that to account for enhanced backscattering from roughness overlying a waveguide structure, multiple scattering theory for the incoherent field is required, beyond the smoothing approximation. This work will examine consequences of their multiple scattering formalism for fields within a waveguide and identify the problems that make the interior problem distinct from that of determining the differential cross section, i.e., the exterior problem.
The ‘‘center-of-gravity’’ effect in dynamic tones
Authors: Anantharaman Jayanth N. , Krishnamurthy Ashok K. , Feth Lawrence L.
Published: July 2002

Earlier work [e.g., Xu et al., J. Acoust. Soc. Am. 101, 3149(A) (1997); Chistovich, ibid. 77, 798–805 (1985)] has demonstrated the spectral center-of-gravity (CoG) effect. The studies have largely concentrated on steady-state signals. Recently, Lublinskaya (1996) has investigated the CoG effect in dynamic synthetic speech. In the study presented here, the CoG effect in dynamic two-tone complexes was investigated. The frequencies of the two tones were held constant while their amplitudes were varied linearly: the amplitude of the lower frequency tone was decreased while that of the higher frequency tone was increased. This causes a variation in the spectral CoG, although the locations of the frequency content remain constant with time. Subjects matched the slope of a linear glide (target) having the same center frequency as the two-tone complex (standard) using a double-staircase procedure. The experiment was carried out for various center frequencies (500–2000 Hz) and frequency separations (0.5–8 ERBs). The center frequency was also roved between trials. Matching experiments were also carried out with another linear glide as the standard. The results of these experiments will be presented and the center-of-gravity effect in these dynamic two-tone complexes will be discussed. [Work supported by AFOSR and OSU-GSARA.]
Model experiment to study sonic boom propagation through turbulence. Part I: General results
Authors: Lipkens Bart , Blackstock David T.
Published: July 2002

A model experiment to study the effect of atmospheric turbulence on sonic booms is reported. The model sonic booms are N waves produced by electric sparks, and the model turbulence is created by a plane jet. Of particular interest are the changes in waveform, peak pressure, and rise time of the model N waves after they have passed through the model turbulence. A review is first given of previous experiments on the effect of turbulence on both sonic booms and model N waves. This experiment was designed so that the scale factor (approximately 10−4) relating the characteristic length scales of the model turbulence to those of atmospheric turbulence is the same as that relating the model N waves to sonic booms. Most of the results reported are for plane waves. Sets of 100 or 200 pressure waveforms were recorded, for both quiet and turbulent air, and analyzed. Sample waveforms, scatter plots of peak pressure and rise time, histograms, and cumulative probability distributions are given. Results are as follows: (1) The model experiment successfully simulates sonic boom propagation through the atmosphere. The waveform distortion of actual sonic booms is reproduced, both in scale and in character, in the laboratory study. (2) Passage through turbulence almost always causes rise time to increase; decreases are rare. (3) Average rise time is always increased by turbulence, threefold for the particular data reported here. (4) Average peak pressure is always decreased by turbulence, but the change is not as striking as that for average rise time.
Efficient numerical simulation of stochastic internal-wave-induced sound-speed perturbation fields
Authors: Colosi John A. , Brown Michael G.
Published: July 2002

An efficient method is presented to numerically simulate stochastic internal-wave-induced sound-speed perturbation fields in deep ocean environments. The sound-speed perturbation field is represented as an internal-wave eigenfunction expansion in which WKB amplitude scaling and stretching of the depth coordinate are exploited. Individual realizations of the sound-speed perturbation field are constructed by evaluating a multidimensional fast Fourier transform of a complex-valued function whose modulus has a known simple form and whose phase is random. Approximations made are shown to be consistent with approximations built into the Garrett–Munk internal-wave spectrum, which is the starting point of this analysis. Both time-varying internal-wave fields in three space dimensions and frozen fields in a vertical plane are considered.
Response to “Comments on ‘A re-examination of risk estimates from the NIOSH Occupational Noise and Hearing Survey’ ” [J. Acoust. Soc. Am. 103, 2734 (1998)]
Authors: Prince Mary M. , Stayner Leslie T. , Smith Randall J. , Gilbert Stephen J.
Published: July 2002

Concern is raised by Dobie [J. Acoust. Soc. Am. 103, 2734 (1998)] regarding a recent analysis [, J. Acoust. Soc. Am. 101, 950–963 (1997)] of the NIOSH Occupational Noise and Hearing Survey data. Specifically, issues are raised concerning (1) definition of hearing handicap, (2) the use of frequency-specific articulation index (AI) weights applied to the binaural pure-tone average of 1, 2, 3, and 4 kHz, and (3) conclusions regarding significant excess risk based on this definition. We have reviewed the development of the definitions of hearing handicap and provide additional support for the use of a hearing handicap definition based on the binaural pure-tone average of 1, 2, 3, and 4 kHz and the weighting of specific frequencies. Furthermore, our definition of noise-induced hearing handicap is similar to one of several proposed by the International Standards Organization (Reference 1999Reference 1990) and the American National Standards Institute (Reference 3Reference 44Reference 1996). Additional analyses show that there is significant evidence of excess risk at daily exposure levels below 85 dB using any of the pure-tone average and/or weighting strategies we have examined. Hence we have provided additional support for our conclusions regarding exposure-response curves and we have reaffirmed that our methods are appropriate for the scope of our analysis.
Detection and control of lithotripsy-induced cavitation in blood
Authors: Jordan Brenda , Bailey Michael R. , Cleveland Robin O. , Crum Lawrence A.
Published: July 2002

Monitoring and controlling cavitation offer ways of isolating the role of cavitation in lithotripsy-induced cell damage. Finger cots containing 7 ml of PBS-diluted blood (3% hematocrit) were treated by 100 lithotripter pulses focused by either a conventional rigid reflector or a pressure-release reflector. The rigid reflector produced 7% hemolysis at 18 kV. The pressure-release reflector, which produces an equally strong acoustic pulse but less intense cavitation, produced 1% hemolysis which was indistinguishable from control levels. A passive cavitation detector consisting of two confocal focused transducers operating in coincidence was used to monitor cavitation within each blood sample. With the rigid reflector, each transducer recorded a spike when pre-existing bubbles were collapsed by the positive portion of the lithotripter pulse and a second spike when the bubbles, caused to grow by the negative portion of the pulse, underwent inertial collapse. The time between spikes was 1.25–1.5 times longer in blood than in water. The results appear to indicate that transient cavitation is an important mechanism in lithotripsy-induced hemolysis, that lithotripter-induced cavitation can be monitored in cell samples, and that bubble dynamics in blood and water are not identical. [Work supported by NIH PO1 DK43881, UW STAR, and DARPA/ONR.]
A Fourier series solution for the radiation impedance of a finite cylinder
Authors: Butler John L. , Butler Alexander L.
Published: July 2002

A mathematical model for the radiation impedance of a finite cylinder with extended rigid ends is developed using a Fourier series approach. This series approach is shown to be possible by modeling the cylinder as a widely separated periodic replica representation. Radiation impedance results are obtained for the cylinder operating in uniform, dipole, and cardioid radial modes of vibration. The cardioid mode is then used as a radiation impedance model for the underwater sound slotted cylinder transducer.
The underwater audiogram of the West Indian manatee (Trichechus manatus)
Authors: Gerstein Edmund R. , Gerstein Laura , Forsythe Steven E. , Blue Joseph E.
Published: July 2002

The hearing thresholds of two adult manatees were measured using a forced-choice two alternative paradigm and an up/down staircase psychometric method. This is the first behavioral audiogram measured for any Sirenian, as well as the first underwater infrasonic psychometric test with a marine mammal. Auditory thresholds were obtained from 0.4 to 46 kHz, and detection thresholds of possible vibrotactile origin were measured at 0.015–0.2 kHz. The U-shaped audiogram demonstrates an upper limit of functional hearing at 46 kHz with peak frequency sensitivity at 16 and 18 kHz (50 dB re: 1μPa). The range of best hearing is 6–20 kHz (approximately 9 dB down from maximum sensitivity). Sensitivity falls 20 dB per octave below 0.8 kHz and approximately 40 dB per octave above 26 kHz. The audiogram demonstrates a wider range of hearing and greater sensitivity than was suggested from evoked potential and anatomical studies. High frequency sensitivity may be an adaptation to shallow water, where the propagation of low frequency sound is limited by physical boundary effects. Hearing abilities of manatees and other marine mammals may have also been shaped by ambient and thermal noise curves in the sea. Inadequate hearing sensitivity at low frequencies may be a contributing factor to the manatees’ inability to effectively detect boat noise and avoid collisions with boats.
Prediction of railway-induced vibration by means of transfer functions
Authors: Peters Juergen , Prestele Gerhard
Published: July 2002

The prediction of train-induced vibrations in urban areas has to meet many, partly contradictory aspects. Accuracy of predicted vibration with respect to disturbance of residents and measures of reduction of ground-borne vibration, unknown conditions of transmission, large number of buildings to investigate, economical and time aspects also have to be taken into account. The extension of an existing above-ground railway into two tracks in dense developement was taken to test a prediction method based on measured transfer functions characterizing the new track. These investigations were done at an intermediate stage of construction without gravel and sleepers. The transfer functions are used to calculate emission spectra based on a known set of train spectra and corresponding transfer functions investigated elsewhere. The train spectra have to match the super/substructure of the new track and characteristics of the train to be predicted (e.g., velocity). Recent results are discussed.
Mechanisms of fine-surface-texture discrimination in human tactile sensation
Authors: Miyaoka Tetsu , Mano Tadaaki , Ohka Masahiro
Published: July 2002

The purpose of this study was to evaluate the ability of touch to discriminate fine-surface textures and to suggest possible mechanisms of the discriminations. Two experiments were performed. In experiment 1, aluminum-oxide abrasive papers were adopted as stimuli, and psychometric functions and difference thresholds were determined in fine-surface-texture discrimination tasks. The grit values of abrasive papers were 400, 600, 1200, 2000, 3000, 4000, and 8000; corresponding average particle sizes were 40, 30, 12, 9, 5, 3, and 1 μm, respectively. Ten subjects participated in experiment 1. The difference thresholds obtained in experiment 1 were between 2.4 and 3.3 μm. In experiment 2, the tasks were discriminations of ridge height. The cross sections of the etched ridges were rectangular and the ridge heights were 6.3, 7.0, 8.6, 10.8, 12.3, 18.5, and 25.0 μm. Six subjects participated in experiment 2. The difference thresholds in experiment 2 were between 0.95 and 2.0 μm. It was reasoned, based on the Weber fraction values calculated from the difference thresholds and on the limit of neural information-processing ability of humans, that the subjects discriminate fine roughness only from the amplitude information presented in surface unevenness.
Thermoacoustics in a single pore with an applied temperature gradient
Authors: Petculescu G. , Wilen L. A.
Published: July 2002

Thermoacoustic effects in a circular pore with an applied temperature gradient are investigated. A volume-modulation technique is employed to measure the compressibility of a gas in the pore directly. When a temperature gradient is imposed on the pore, the compressibility is sensitive to thermoacoustic effects which depend on both thermal and viscous properties of the gas. Experimental results for argon and nitrogen covering a wide range of temperature gradients are presented and compared with theoretical predictions. Good agreement is found. Viscous dissipation is shown to be negligible in the arrangement studied, and the effect of viscosity is to modify the velocity profile in a way which enhances thermoacoustic gain. The measurements characterize certain thermoacoustic properties of the pore and the technique can be extended to study novel stack geometries such as stacked screens, pin arrays with varying pin orientations, reticulated vitreous carbon (RVC), or others.
Kinematic evidence for the existence of gradient speech errors
Authors: Pouplier Marianne , Chen Larissa , Goldstein Louis , Byrd Dani
Published: July 2002

Speech errors have long been appealed to as evidence for segmental units in speech production. However, if speech errors can be shown to be potentially gradient, as opposed to always categorical, in nature, the view of segments such as ‘‘swapping places’’ must be called into question. Severe limitation of a transcription approach to evaluating speech errors is that gradient errors may go unrepresented in the transcriptional record if they are obscured by other articulatory events due to the coproduction of speech gestures. In a pioneering production study of errors, Mowrey and MacKay [J. Acoust. Soc. Am. 88, 1299–1312 (1990)] present EMG data that suggest that gradient errors do exist, although they are not always audible. However, the anomalous activity they observe in single-motor-unit recordings does not preclude the possibility that a segmental unit was either still produced correctly via compensation by other muscle activity or omitted in its entirety in the articulatory kinematics. Using magnetometry, the present study for the first time is able to provide articulatory movement tracking data that exhibit gradient errors in phrases like ‘‘cop top’’ and ‘‘Bligh Bay’’ repeated rapidly. For example, during the [t] in ‘‘cop top’’ some tokens show a small (sometimes inaudible) raising of the tongue dorsum. [Work supported by NIH.]
Different auditory filter bandwidth estimates based on profile analysis, notched noise, and hybrid tasks
Authors: Lentz Jennifer J. , Richards Virginia M. , Matiasek Matthew R.
Published: July 2002

Auditory filter bandwidths were estimated in three experiments. The first experiment was a profile-analysis experiment. The stimuli were composed of sinusoidal components ranging in frequency from 200 to 5000 Hz. The standard stimulus was the sum of equal-amplitude tones, and the signal stimulus had a power spectrum that varied up–down…up–down. The number of components ranged from four to 60. Interval-by-interval level randomization prevented the change in level of a single component from reliably indicating the change from standard to signal. The second experiment was a notched-noise experiment in which the 1000-Hz tone to be detected was added to a noise with a notch arithmetically centered at 1000 Hz. Detection thresholds were estimated both in the presence of and in the absence of level randomization. In the third, hybrid, experiment a 1000-Hz tone was to be detected, and the masker was composed of equal-amplitude sinusoidal components ranging in frequency from 200 to 5000 Hz. For this experiment, thresholds were estimated both in the presence and absence of level variation. For both the notched-noise and hybrid experiments, only modest effects of level randomization were obtained. A variant of Durlach et al.’s channel model [“Towards a model for discrimination of broadband signals,” J. Acoust. Soc. Am. 80, 63–72 (1986)] was used to estimate auditory filter bandwidths for all three experiments. When a two-parameter roex(p,r) filter weighting function was used to fit the data, bandwidth estimates were approximately two to three times as large for the two detection tasks than for the profile-analysis task.
Auditory-nerve-fiber responses to high-level clicks: Interference patterns indicate that excitation is due to the combination of multiple drives
Authors: Lin Tai , Guinan John J.
Published: July 2002

There has been no systematic study of auditory-nerve-fiber (ANF) responses to high-level clicks despite the advantages of clicks in revealing the natural resonances of a system. Cat single ANFs were studied using clicks up to 120 dB pSPL. Peri-stimulus-time (PST) histograms of responses were corrected for refractory effects, and compound PST (cPST) histograms were formed from rarefaction- and condensation-click PSTs. At low levels the responses followed the classic picture with each cPST appearing to be from a single resonant system followed by low-pass filtering that reduces high-frequency synchrony. In fibers across all characteristic frequencies, there were significantly different patterns at high click levels including several nonclassic features and “phase reversals,” i.e., a peak in the rarefaction-click PST at low levels was replaced at high levels by a peak at the same latency in the condensation-click PST. There were two separate regions of nonclassic features and phase reversals, which indicates that auditory-nerve fibers are excited by the combination at some stage in the cochlea of at least three excitation drives derived from the acoustic stimulus. These data support the interpretation that the cochlear partition vibrates in multiple resonant modes with each mode producing one excitation drive and that the mix of modes varies with sound level.
Iterative Numerical Methods for Some Integral Equations Arising in Rheology
Authors: Tanner R. I. , Williams G.
Published: July 2002

One of the first applications of integral equation inversion techniques in rheology was the exact result of Weissenberg, which enables the shear curve to be obtained from a laminar pipeflow experiment. It is shown that numerical solution of the integral equations occurring for this and other common experiments may be used instead. Numerical inversion programs have been written for the pipeflow and Couette problems. Certain, more difficult inversions, arising with elastic fluid constitutive relations, are also treated; in some cases a simple version of the KBKZ theory seems fairly realistic over a wide range of experiments.
Measurement of the Axial Pressure Distribution of Molten Polymers in Flow through a Rectangular Duct
Authors: Han C. D. , Charles M.
Published: July 2002

The authors have experimentally determined the axial pressure distributions for the flow of polyethylene and polypropylene melts through a rectangular duct having an aspect ratio of 2. “Exit pressures,” which were found by extrapolating the pressure profiles to the duct exit, were found to correlate well with the volumetric flow rate. This result is quite understandable in light of previous results regarding the flow of melts through circular capillaries, because the nature of fluid flow through a capillary is the same as that of the flow through a rectangular duct having a very large aspect ratio (i.e., simple shearing flow). Thus, the rheological implication of the “exit pressure” is the same for both of these geometries. The analysis of flow through a rectangular duct having a very large aspect ratio shows that the normal stress difference is approximately equal to the “exit pressure” for polymer melts. A preliminary analysis of flow through a rectangular duct having a small aspect ratio is presented, and it gives a clear direction to future experiment.
Influence of phase separation on the linear viscoelastic behavior of a miscible polymer blend
Authors: Mani Suresh , Malone Michael F. , Winter H. Henning
Published: July 2002

The influence of phase separation on the linear viscoelastic response has been studied in miscible blends of polystyrene and poly(vinyl methyl ether) with a lower critical solution temperature near 110 °C. At temperatures between 25 and 155 °C, and for compositions in the range 20% to 60% polystyrene, the complex moduli G′ and G″ were measured at frequencies in the range of 0.01 to 100 rad/s. Time–temperature superposition was applied in the single phase region to obtain the complex modulus over eight decades of frequency. Increasing the polystyrene content resulted in an increase in the zero-shear viscosity and a shift of the terminal behavior to lower frequencies or longer times. The phase separation above the lower critical solution temperature was measured as a sudden increase in the fluorescence intensity of an anthracene-labeled polystyrene (approximately 1 wt % in the blend), using an optical probe in the rheometer fixture. For the 20/80 and 40/60 PS/PVME samples, the terminal zone was in the accessible frequency window and phase separation was accompanied with a large increase in G′ and G″. In contrast, the complex modulus of the 60/40 PS/PVME blend could not be measured near the terminal zone and the G′ and G″ did not exhibit any significant changes near the phase transition temperature.
X-ray diffraction data for flux-grown calcium hydroxyapatite whiskers
Authors: Tas A. Cüneyt
Published: July 2002

Calcium hydroxyapatite (Ca10(PO4)6(OH)2) whiskers were prepared by using the technique of molten salt synthesis with the fluxing agent of potassium sulphate (K2SO4). A tentative x-ray diffraction (XRD) pattern was suggested for the produced whiskers. Phase purity, composition, and morphology of the whiskers were investigated by powder XRD, inductively coupled plasma-atomic emission spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy, respectively.
Artificial Intelligence in Breast Cancer Screening
Authors: Potnis Kunal C. , Ross Joseph S. , Aneja Sanjay , Gross Cary P. , Richman Ilana B.
Published: November 2022

Importance

Contemporary approaches to artificial intelligence (AI) based on deep learning have generated interest in the application of AI to breast cancer screening (BCS). The US Food and Drug Administration (FDA) has approved several next-generation AI products indicated for BCS in recent years; however, questions regarding their accuracy, appropriate use, and clinical utility remain.

Objectives

To describe the current FDA regulatory process for AI products, summarize the evidence used to support FDA clearance and approval of AI products indicated for BCS, consider the advantages and limitations of current regulatory approaches, and suggest ways to improve the current system.

Evidence Review

Premarket notifications and other publicly available documents used for FDA clearance and approval of AI products indicated for BCS from January 1, 2017, to December 31, 2021.

Findings

Nine AI products indicated for BCS for identification of suggestive lesions and mammogram triage were included. Most of the products had been cleared through the 510(k) pathway, and all clearances were based on previously collected retrospective data; 6 products used multicenter designs; 7 products used enriched data; and 4 lacked details on whether products were externally validated. Test performance measures, including sensitivity, specificity, and area under the curve, were the main outcomes reported. Most of the devices used tissue biopsy as the criterion standard for BCS accuracy evaluation. Other clinical outcome measures, including cancer stage at diagnosis and interval cancer detection, were not reported for any of the devices.

Conclusions and Relevance

The findings of this review suggest important gaps in reporting of data sources, data set type, validation approach, and clinical utility assessment. As AI-assisted reading becomes more widespread in BCS and other radiologic examinations, strengthened FDA evidentiary regulatory standards, development of postmarketing surveillance, a focus on clinically meaningful outcomes, and stakeholder engagement will be critical for ensuring the safety and efficacy of these products.
Impact of the COVID‐19 Pandemic on Early Career Investigators in Rheumatology: Recommendations to Address Challenges to Early Research Careers
Authors: Kuhn Kristine A. , Stahly Andrew , Konig Maximilian F. , Carandang Kristine , Herndon Connie , Backman Catherine , Callahan Leigh F. , Schulert Grant , Fraenkel Liana , Ogdie Alexis ,   the American College of Rheumatology Committee on Research
Published: November 2022

Objective

The COVID‐19 pandemic has impacted the careers of trainees and early career investigators (ECIs). We sought to assess how the American College of Rheumatology (ACR) and the Rheumatology Research Foundation (RRF) can address the needs of those pursuing research careers.

Methods

The Committee on Research created a survey to assess the impact of COVID‐19 and identify topics for the ACR and the RRF to address. In fall of 2020, we surveyed postdoctoral trainees and ECIs within 9 years of terminal training. Responses were analyzed using descriptive statistics and qualitative content analysis.

Results

Twenty‐one percent of invitees responded to the survey (n = 365); of these, 60% were pursuing careers in academic research. Seventy‐five percent of respondents in academic research career paths placed their primary projects on hold during the pandemic. The number of individuals pursuing a research career from 2020 to 2021 decreased by 5%. Respondents reported funding, caregiving, and lack of preliminary data as significant challenges. Suggested impactful interventions included increased funding, funding process reform, and expanding mentoring and networking resources.

Conclusion

Major stressors identified during the pandemic included increased caregiving responsibilities and difficulty obtaining data and funding, for which respondents suggested increases and changes in funding programs as well as more mentoring and networking opportunities. Based on these, the Committee on Research proposes 3 priorities: 1) flexible funding mechanisms for ECIs and additional support for those impacted by caregiving; 2) virtual and in‐person programs for career development and networking; and 3) curated content relevant to building a research career available on demand.
Patient and Physician Global Assessments of Disease Status in Systemic Sclerosis
Authors: Ross Laura , Nikpour Mandana , D'Aoust Julie , Khanna Dinesh , Merkel Peter A. , Pauling John D. , Baron Murray
Published: November 2022

Global assessments of disease by both patients and physicians are widely used in clinical studies of systemic sclerosis (SSc). They are commonly secondary end points in randomized controlled trials (RCTs) and are considered important items in composite measures of treatment response. A comprehensive literature review was conducted of the formats, wording, and clinimetric properties of the patient global assessment of disease status (PtGA) and physician global assessment of disease status (PhGA) used in RCTs of SSc. Marked heterogeneity was found in the wording and measurement scales of the global assessments applied in RCTs. These instruments were not developed using rigorous methodology and have not been fully validated. There is a pressing need for standardization and validation of patient and physician global assessment tools in SSc to enable universal application of these measures across RCTs in SSc.
N.J. providers serving dually diagnosed eligible for recovery‐focused training
Authors: Enos Gary
Published: November 2022

New Jersey provider agencies treating patients with co‐occurring substance use and mental health disorders are among the target recipients in a training initiative to promote the use of recovery‐oriented cognitive therapy. State officials’ provision of $500,000 to conduct the training and ongoing mentoring of clinicians is designed to encourage wider use of a strengths‐based treatment seen as particularly suited to individuals who hesitate to engage in treatment due to mistrust, a history of institutionalization or other common barriers.
Boo! The addiction treatment false binary
Authors: Ventrell Marvin
Published: November 2022

Please forgive the abuse of the Halloween metaphor as I find myself spooked by the specter of an addiction treatment false binary in the op‐ed in the innovations issue (see “Harm reduction innovation: Abstinence, move over,” ADAW Oct. 31; https://onlinelibrary.wiley.com/doi/full/10.1002/adaw.33600).
Programmable Wavefront Control in the Visible Spectrum Using Low‐Loss Chalcogenide Phase‐Change Metasurfaces
Authors: Moitra Parikshit , Wang Yunzheng , Liang Xinan , Lu Li , Poh Alyssa , Mass Tobias W.W. , Simpson Robert E. , Kuznetsov Arseniy I. , Paniagua‐Dominguez Ramon
Published: November 2022

All‐dielectric metasurfaces provide unique solutions for advanced wavefront manipulation of light with complete control of amplitude and phase at sub‐wavelength scales. One limitation, however, for most of these devices is the lack of any post‐fabrication tunability of their response. To break this limit, a promising approach is employing phase‐change materials (PCMs), which provide fast, low energy, and non‐volatile means to endow metasurfaces with a switching mechanism. In this regard, great advancements have been done in the mid‐infrared and near‐infrared spectrum using different chalcogenides. In the visible spectral range, however, very few devices have demonstrated full phase manipulation, high efficiencies, and reversible optical modulation. In this work, a programmable all‐dielectric Huygens’ metasurface made of antimony sulfide (Sb2S3) PCM is experimentally demonstrated, a low loss and high‐index material in the visible spectral range with a large contrast (≈0.5) between its amorphous and crystalline states. ≈2π phase modulation is shown with high associated transmittance and it is used to create programmable beam‐steering devices. These novel chalcogenide PCM metasurfaces have the potential to emerge as a platform for next‐generation spatial light modulators and to impact application areas such as programmable and adaptive flat optics, light detection and ranging (LiDAR), and many more.
The Negative‐Charge‐Triggered “Dead Zone” between Electrode and Current Collector Realizes Ultralong Cycle Life of Aluminum‐Ion Batteries
Authors: Guan Wei , Huang Zheng , Wang Wei , Song Wei‐Li , Tu Jiguo , Luo Yiwa , Lei Haiping , Wang Mingyong , Jiao Shuqiang
Published: November 2022

Typically, volume expansion of the electrodes after intercalation of active ions is highly undesirable yet inetvitable, and it can significantly reduce the adhesion force between the electrodes and current collectors. Especially in aluminum‐ion batteries (AIBs), the intercalation of large‐sized AlCl4− can greatly weaken this adhesion force and result in the detachment of the electrodes from the current collectors, which seems an inherent and irreconcilable problem. Here, an interesting concept, the “dead zone”, is presented to overcome the above challenge. By incorporating a large number of OH− and COOH− groups onto the surface of MXene film, a rich negative‐charge region is formed on its surface. When used as the current collector for AIBs, it shields a tiny area of the positive electrode (adjacent to the current collector side) from AlCl4− intercalation due to the repulsion force, and a tiny inert layer (dead zone) at the interface of the positive electrode is formed, preventing the electrode from falling off the current collector. This helps to effectively increase the battery's cycle life to as high as 50 000 times. It is believed that the proposed concept can be an important reference for future development of current collectors in rocking chair batteries.
Simultaneous Photoelectrocatalytic Oxidation and Nitrite‐Ammonia Conversion with Artificial Photoelectrochemistry Cells
Authors: Song Yurou , Wu Yunzhen , Cao Shuyan , Zhang Yanxue , Luo Degen , Gao Junfeng , Li Zhuwei , Sun Licheng , Hou Jungang
Published: November 2022

Artificial photoelectrochemistry system harvests solar energy for solar fuel conversion by use of semiconductor anode and cathode. However, the low overall performance of this integrated system is limited by the compatibility and durability. Herein, a compact heterostructure photoanode exhibits >98% selective photoelectrocatalytic oxidation conversion and >99% Faradaic efficiency of benzyl alcohol oxidation at 0.67 V versus reversible hydrogen electrode in comparison of single‐phase photoanodes. Density functional theory calculations reveal the heterointerface is responsible for the appreciable electronic interaction and the accelerated charge transport, exploring the radical relay pathway as the selective oxidation mechanism. Especially, the integrated photoelectrochemistry cell is developed by heterostructure photoanode and protective photocathode, simultaneously enabling the efficient photoelectrocatalytic oxidation conversion and nitrite reduction reaction to ammonia synthesis under ambient conditions with a maximum Faradaic efficiency >98%. This work sheds light on rational design and the construction of artificial photoelectrochemistry cells towards solar energy conversion.
Ionic Organic Thermoelectrics with Impressively High Thermopower for Sensitive Heat Harvesting Scenarios
Authors: Pai Ya‐Hsin , Tang Junhui , Zhao Yan , Liang Ziqi
Published: November 2022

As the worldwide energy crisis is worsened, thermoelectric materials that can harvest low‐grade waste heat and directly convert it into electricity provide promising alternative energy sources. Emerging ionic thermoelectrics (iTEs) have recently attracted widespread attention thanks to their impressively high thermopower that can reach hundreds of times more than conventional electronic thermoelectrics (eTEs). Based on the Soret effect, the performances of iTEs depend on the thermo‐diffusion of mobile ions in electrolytes, resulting in electrical characteristics distinct from eTE materials and opening up additional potential applications of thermoelectrics. Among these materials, organics‐based iTEs (i‐OTEs) provide unique advantages such as low‐cost, light‐weight, and eco‐friendliness, thereby offering more promising application scenarios that can utilize dissipated heat, for example, from human bodies or mobile devices. This concise review begins with the comparison of iTE and eTE, and then discusses their different mechanisms and applied devices in detail. Next, the recent advances of i‐OTEs will be in‐depth highlighted, including the merits and weaknesses of representative types of materials, effects of additives, and effective strategies for performance optimization. Finally, the state‐of‐the‐art achievements of i‐OTEs are summarized, and an overview is provided of the existing challenges and an outlook of prospective development and applications in future efforts.
Steel Anti‐Corrosion Strategy Enables Long‐Cycle Zn Anode
Authors: Tian Han , Yang Jin‐Lin , Deng Yirui , Tang Wenhao , Liu Ruiping , Xu Chenyang , Han Peng , Fan Hong Jin
Published: November 2022

The progress of aqueous zinc batteries (AZBs) is limited by the poor cycling life due to Zn anode instability, including dendrite growth, surface corrosion, and passivation. Inspired by the anti‐corrosion strategy of steel industry, a compounding corrosion inhibitor (CCI) is employed as the electrolyte additive for Zn metal anode protection. It is shown that CCI can spontaneously generate a uniform and ≈30 nm thick solid‐electrolyte interphase (SEI) layer on Zn anode with a strong adhesion via ZnO bonding. This SEI layer efficiently prohibits water corrosion and guides homogeneous Zn deposition without obvious dendrite formation. This enables reversible Zn deposition and dissolution for over 1100 h under the condition of 1 mA cm−2 and 1 mAh cm−2 in symmetric cells. The Zn‐MnO2 full cells with CCI‐modified electrolyte deliver an ultralow capacity decay rate (0.013% per cycle) at 0.5 A g−1 over 1000 cycles. Such an innovative strategy paves a low‐cost way to achieve AZBs with long lifespan.
Kontrolle der Selektivität in Shuttle‐Heterodifunktionalisierungen: Elektrochemische Transfer‐Halothiolierung von Alkinen
Authors: Dong Xichang , Klein Martin , Waldvogel Siegfried R. , Morandi Bill
Published: November 2022

Die Shuttle‐Heterodifunktionalisierungsreaktion, bei der zwei chemisch unterschiedliche funktionelle Gruppen zwischen zwei Molekülen übertragen werden, war lange Zeit ein unerreichtes Ziel, da die Kontrolle der Chemo‐, Regio‐ und Stereoselektivität eine große Herausforderung darstellt. Wir präsentieren hier eine elektrochemische Shuttle‐Reaktion (e‐Shuttle), um selektiv eine RS‐ und eine X‐Gruppe zwischen β‐Halogensulfiden und ungesättigten Kohlenwasserstoffen über einen konsekutiv gepaarten Elektrolyse‐Mechanismus zu übertragen. Die bevorzugte anodische Oxidation des einen Anions gegenüber dem anderen, welche aus ihren unterschiedlichen Redoxpotentialen resultiert, spielt eine entscheidende Rolle bei der Kontrolle der hohen Chemoselektivität dieses Prozesses. Diese leicht skalierbare Methode ermöglicht die Herstellung einer Vielzahl von unterschiedlich funktionalisierten β‐Halogenalkenylsulfiden in beispielloser Chemo‐, Regio‐ und Stereoselektivität unter Verwendung leicht handhabbarer Surrogate, z. B. 2‐Bromethyl‐sulfiden, wodurch die Handhabung von korrosiven und oxidativ wirkenden RS−Br‐Reagenzien vermieden wird. In einem breiteren Zusammenhang eröffnen diese Ergebnisse neue Strategien für selektive Shuttle‐Difunktionalisierungsreaktionen.