bluuebunny/crossref_metadata_2025 huggingface dataset:
Association between Air Pollution and Daily Consultations with General Practitioners for Allergic Rhinitis in London, United Kingdom
Authors: Hajat S. , Haines A. , Atkinson R. W. , Bremner S. A. , Anderson H. R. , Emberlin J.
Published: July 2002

Few published studies have looked at the health effects of air pollution in the primary care setting, and most have concentrated on lower rather than upper respiratory diseases. The authors investigated the association of daily consultations with general practitioners for allergic rhinitis with air pollution in London, United Kingdom. Generalized additive models were used to regress time series of daily numbers of patients consulting for allergic rhinitis against 1992–1994 measures of air pollution, after control for possible confounders and adjustment for overdispersion and serial correlation. In children, a 10th–90th percentile increase in sulfur dioxide (SO2) levels 4 days prior to consultation (13–31 μg/m3) was associated with a 24.5% increase in consultations (95% confidence interval: 14.6, 35.2; p < 0.00001); a 10th–90th percentile increase in averaged ozone (O3) concentrations on the day of consultation and the preceding 3 days (6–29 parts per billion) was associated with a 37.6% rise (95% confidence interval: 23.3, 53.5; p < 0.00001). For adults, smaller effect sizes were observed for SO2 and O3. The association with SO2 remained highly significant in the presence of other pollutants. This study suggests that air pollution worsens allergic rhinitis symptoms, leading to substantial increases in consultations. SO2 and O3 seem particularly responsible, and both seem to contribute independently.
VARSPLIC: alternatively-spliced protein sequences derived from
SWISS-PROT and TrEMBL
Authors: Kersey Paul , Hermjakob Henning , Apweiler Rolf
Published: July 2002

Summary: The program varsplic.pl uses information present in the SWISS-PROT and TrEMBL databases to create new records for alternatively spliced isoforms. These new records can be used in similarity searches.

Availability: The program is available at ftp://ftp.ebi.ac.uk/pub/software/swissprot/, together with regularly updated output files.

Contact: pkersey@ebi.ac.uk

To whom correspondence should be addressed.
ODNBase—a web database for antisense oligonucleotide
effectiveness studies
Authors: Giddings Michael C. , Matveeva Olga V. , Atkins John F. , Gesteland Raymond F.
Published: July 2002

Summary: ODNBase is a database of antisense oligodeoxynucleotides targeted to mammalian mRNAs that were reported in the literature. It includes the oligo sequences tested, the measured effectiveness, the RNA that was targeted, the type of measurement assay used, the oligo concentration applied, and the reference for each oligo. It provides a searchable interface by motif content, activity level, applied concentration and RNA name. Oligo lists matching search criteria can be downloaded in a spreadsheet compatible format.

Availability: The database is available at http://antisense.genetics.utah.edu/, by clicking the ‘ODNBase’ link.

Contact: giddings@genetics.utah.edu
Efficient primer design algorithms
Authors: Kämpke Thomas , Kieninger Markus , Mecklenburg Michael
Published: July 2002

Motivation: Primer design involves various parameters such as string-based alignment scores, melting temperature, primer length and GC content. This entails a design approach from multicriteria decision making. Values of some of the criteria are easy to compute while others require intense calculations.

Results: The reference point method was found to be tractable for trading-off between deviations from ideal values of all the criteria. Some criteria computations are based on dynamic programs with value iteration whose run time can be bounded by a low-degree polynomial. For designing standard PCR primers, the scheme offers in a relative gain in computing speed of up to \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(50\ :\ 1\) \end{document}over ad-hoc computational methods. Single PCR primer pairs have been used as model systems in order to simplify the quantization of the computational acceleration factors. The program has been structured so as to facilitate the analysis of large numbers of primer pairs with minor modifications. The scheme significantly increases primer design throughput which in turn facilitates the use of oligonucleotides in a wide range of applications including: multiplex PCR and other nucleic acid-based amplification systems, as well as in zip code targeting, oligonucleotide microarrays and nucleic acid-based nanoengineering.

Availability: A public version of the software DOPRIMER is accessible under http://doprimer.interactiva.de

Contact: kaempke@faw.uni-ulm.de
Coordinated response of mammalian Rad51 and Rad52 to DNA damage
Authors: Liu Yilun , Maizels Nancy
Published: July 2002

Biochemical analysis has shown that mammalian Rad51 and Rad52 interact and synergize in DNA recombination reactions in vitro, but these proteins have not been shown to function together in response to DNA damage in vivo. By analysis of murine cells expressing murine Rad52 tagged with green fluorescent protein (GFP)–Rad52, we now show that DNA damage causes Rad51 and GFP–Rad52 to colocalize in distinct nuclear foci. Cells expressing GFP–Rad52 show both increased survival and an increased number of Rad51 foci, raising the possibility that Rad52 is limiting for repair. These observations provide evidence of coordinated function of Rad51 and Rad52 in vivo and support the hypothesis that Rad52 plays an important role in the DNA damage response in mammalian cells.
Actin pedestal formation by enteropathogenic Escherichia coli and intracellular motility of Shigella flexneri are abolished in N‐WASP‐defective cells
Authors: Lommel Silvia , Benesch Stefanie , Rottner Klemens , Franz Thomas , Wehland Jürgen , Kühn Ralf
Published: July 2002

In mammalian cells, actin dynamics is tightly controlled through small GTPases of the Rho family, WASP/Scar proteins and the Arp2/3 complex. We employed Cre/loxP‐mediated gene targeting to disrupt the ubiquitously expressed N‐WASP in the mouse germline, which led to embryonic lethality. To elucidate the role of N‐WASP at the cellular level, we immortalized embryonic fibroblasts and selected various N‐WASP‐defective cell lines. These fibroblasts showed no apparent morphological alterations and were highly responsive to the induction of filopodia, but failed to support the motility of Shigella flexneri. In addition, enteropathogenic Escherichia coli were incapable of inducing the formation of actin pedestals in N‐WASP‐defective cells. Our results prove the essential role of this protein for actin cytoskeletal changes induced by these bacterial pathogens in vivo and in addition show for the first time that N‐WASP is dispensible for filopodia formation.
Release factor 2 frameshifting sites in different bacteria
Authors: Baranov Pavel V , Gesteland Raymond F , Atkins John F
Published: July 2002

The mRNA encoding Escherichia coli polypeptide chain release factor 2 (RF2) has two partially overlapping reading frames. Synthesis of RF2 involves ribosomes shifting to the +1 reading frame at the end of the first open reading frame (ORF). Frameshifting serves an autoregulatory function. The RF2 gene sequences from the 86 additional bacterial species now available have been analyzed. Thirty percent of them have a single ORF and their expression does not require frameshifting. In the ∼70% that utilize frameshifting, the sequence cassette responsible for frameshifting is highly conserved. In the E. coli RF2 gene, an internal Shine–Dalgarno (SD) sequence just before the shift site was shown earlier to be important for frameshifting. Mutagenic data presented here show that the spacer region between the SD sequence and the shift site influences frameshifting, and possible mechanisms are discussed. Internal translation initiation occurs at the shift site, but any functional role is obscure.
Experimental evolution recapitulates natural evolution
Authors: Wichman H. A. , Scott L. A. , Yarber C. D. , Bull J. J.
Published: July 2002

Genomes of the closely related bacteriophages ϕX174 and S13 are 5386 bases long and differ at 114 nucleotides, affecting 28 amino acids. Both parental phages were adapted to laboratory culture conditions in replicate lineages and analysed for nucleotide changes that accumulated experimentally. Of the 126 experimental substitutions, 90% encoded amino–acid changes, and 62% of the substitutions occurred in parallel in more than one experimental line. Furthermore, missense changes at 12 of the experimental sites were at residues differing between the parental phages; in ten cases the ϕX174 experimental lineages were convergent with the S13 parent, or vice versa, at both the nucleotide and amino–acid levels. Convergence at a site was even obtained in both directions in three cases. These results point to a limited number of pathways taken during evolution in these viruses, and also raise the possibility that much of the amino–acid variation in the natural evolution of these viruses has been selected.
RNA-binding proteins and circadian rhythms inArabidopsis thaliana
Authors: Staiger Dorothee
Published: July 2002

AnArabidopsistranscript preferentially expressed at the end of the daily light period codes for the RNA–binding proteinAtGRP7. A reverse genetic approach inArabidopsis thalianahas revealed its role in the generation of circadian rhythmicity:AtGRP7 is part of a negative feedback loop through which it influences the oscillations of its own transcript. Biochemical and genetic experiments indicate a mechanism for this autoregulatory circuit:Atgrp7 gene transcription is rhythmically activated by the circadian clock during the day. TheAtGPR7 protein accumulates with a certain delay and represses further accumulation of its transcript, presumably at the post–transcriptional level. In this respect, theAtGRP7 feedback loop differs from known circadian oscillators in the fruitflyDrosophilaand mammals based on oscillating clock proteins that repress transcription of their own genes with a 24 h rhythm. It is proposed that theAtGRP7 feedback loop may act within an output pathway from theArabidopsisclock.
Requirement of the JIP1 scaffold protein for stress-induced JNK activation
Authors: Whitmarsh Alan J. , Kuan Chia-Yi , Kennedy Norman J. , Kelkar Nyaya , Haydar Tarik F. , Mordes John P. , Appel Michael , Rossini Aldo A. , Jones Stephen N. , Flavell Richard A. , Rakic Pasko , Davis Roger J.
Published: July 2002

The c-Jun N-terminal kinase (JNK) signal transduction pathway is activated in response to the exposure of cells to environmental stress. Components of the JNK signaling pathway interact with the JIP1 scaffold protein. JIP1 is located in the neurites of primary hippocampal neurons. However, in response to stress, JIP1 accumulates in the soma together with activated JNK and phosphorylated c-Jun. Disruption of theJip1 gene in mice by homologous recombination prevented JNK activation caused by exposure to excitotoxic stress and anoxic stress in vivo and in vitro. These data show that the JIP1 scaffold protein is a critical component of a MAP-kinase signal transduction pathway.
Genomic Dissection of Genotype × Environment Interactions Conferring Adaptation of Cotton to Arid Conditions
Authors: Saranga Yehoshua , Menz Mónica , Jiang Chun-Xiao , Wright Robert J. , Yakir Dan , Paterson Andrew H.
Published: July 2002

The interaction of genotype with environment is of primary importance in many aspects of genomic research and is a special priority in the study of major crops grown in a wide range of environments. Water deficit, the major factor limiting plant growth and crop productivity worldwide, is expected to increase with the spread of arid lands. In genetically equivalent cotton populations grown under well-watered and water-limited conditions (the latter is responsible for yield reduction of ∼50% relative to well-watered conditions), productivity and quality were shown to be partly accounted for by different quantitative trait loci (QTLs), indicating that adaptation to both arid and favorable conditions can be combined in the same genotype. QTL mapping was also used to test the association between productivity and quality under water deficit with a suite of traits often found to differ between genotypes adapted to arid versus well-watered conditions. In this study, only reduced plant osmotic potential was clearly implicated in improved cotton productivity under arid conditions. Genomic tools and approaches may expedite breeding of genotypes that respond favorably to specific environments, help test roles of additional physiological factors, and guide the isolation of genes that protect crop performance under arid conditions toward improved adaptation of crops to arid cultivation.
Mediodorsal Thalamic Lesions Impair Trace Eyeblink Conditioning in the Rabbit
Authors: Powell Donald A. , Churchwell John
Published: July 2002

Rabbits received lesions of the mediodorsal nucleus of the thalamus (MDN) or sham lesions and were subjected to classical eyeblink (EB) and heart rate (HR) conditioning. All animals received trace conditioning, with a .5-sec tone conditioned stimulus, a .5-sec trace period, and a 50-msec periorbital shock unconditioned stimulus. Animals with MDN lesions acquired the EB conditioned response (CR) more slowly than sham-lesioned animals. However, previous studies have shown that MDN damage does not affect delay conditioning using either .5-sec or 1-sec interstimulus intervals. The lesions had no significant effect on the HR CR. These results suggest that information processed by MDN and relayed to the prefrontal cortex is required for somatomotor response selection under nonoptimal learning conditions.
Toward clinical application of prompt gamma spectroscopy for in vivo monitoring of boron uptake in boron neutron capture therapy
Authors: Munck af Rosenschöld P. M. , Verbakel W. F. A. R. , Ceberg C. P. , Stecher‐Rasmussen F. , Persson B. R. R.
Published: July 2002

In boron neutron capture therapy (BNCT) the absorbed dose to the tumor cells and healthy tissues depends critically on the boron uptake. Pronounced individual variations in the uptake patterns have been observed for two boron compounds currently used in clinical trials. This implies a high uncertainty in the determination of the boron dose component. In the present work a technique known as prompt gamma spectroscopy (PGS) is studied that potentially can be used for in vivo and noninvasive boron concentration determination at the time of the treatment. The technique is based upon measurement of gamma rays promptly emitted in the and reactions. The aim of this work is to prepare the present setup for clinical application as a monitor of boron uptake in BNCT patients. Therefore, a full calibration and a set of phantom experiments were performed in a clinical setting. Specifically, a nonuniform boron distribution was studied; a skin/dura, a larger blood vessel, and tumor within a head phantom was simulated. The results show that it is possible to determine a homogeneous boron concentration of 5 μg/g within ±3% (1 standard deviation). In the nonuniform case, this work shows that the boron concentration can be determined through a multistep measurement procedure, however, with a somewhat higher uncertainty (∼10%). The present work forms the basis for a subsequent clinical application of the PGS setup aimed at in vivo monitoring of boron uptake.
Quantifying uncertainty in geoacoustic inversion. II. Application to broadband, shallow-water data
Authors: Dosso Stan E. , Nielsen Peter L.
Published: July 2002

This paper applies the new method of fast Gibbs sampling (FGS) to estimate the uncertainties of seabed geoacoustic parameters in a broadband, shallow-water acoustic survey, with the goal of interpreting the survey results and validating the method for experimental data. FGS applies a Bayesian approach to geoacoustic inversion based on sampling the posterior probability density to estimate marginal probability distributions and parameter covariances. This requires knowledge of the statistical distribution of the data errors, including both measurement and theory errors, which is generally not available. Invoking the simplifying assumption of independent, identically distributed Gaussian errors allows a maximum-likelihood estimate of the data variance and leads to a practical inversion algorithm. However, it is necessary to validate these assumptions, i.e., to verify that the parameter uncertainties obtained represent meaningful estimates. To this end, FGS is applied to a geoacoustic experiment carried out at a site off the west coast of Italy where previous acoustic and geophysical studies have been performed. The parameter uncertainties estimated via FGS are validated by comparison with: (i) the variability in the results of inverting multiple independent data sets collected during the experiment; (ii) the results of FGS inversion of synthetic test cases designed to simulate the experiment and data errors; and (iii) the available geophysical ground truth. Comparisons are carried out for a number of different source bandwidths, ranges, and levels of prior information, and indicate that FGS provides reliable and stable uncertainty estimates for the geoacoustic inverse problem.
Single bubble sonoluminescence driven by non-simple-harmonic ultrasounds
Authors: Chen Weizhong , Chen Xi , Lu Meijun , Miao Guoqing , Wei Rongjue
Published: July 2002

The dependence of the single bubble sonoluminescence (SBSL) on the waveforms of the driving ultrasound has been investigated by both experiment and numerical calculation. Three types of non-simple-harmonic waves, the rectangular, triangular and as well as the sinusoidal wave with a pulse, are used to drive the SBSL in our research. The triangular wave is the most effective, while the rectangular wave is the worst and the sinusoidal wave in the middle. However, the rectangular wave drives the brightest SBSL among those waves if the sound pressure amplitude keeps constant. When we use a simple-harmonic wave with a pulse as the driving sound, stable and periodic SBSL flashes have been observed. An increase in the flash intensity can be observed as the pulse is put at a suitable phase related to the sinusoidal wave. All of the observations are investigated numerically. Well qualitative agreements between the numerical simulations and the experimental measurements have been achieved.
An adaptive noise reduction stethoscope for auscultation in high noise environments
Authors: Patel Samir B. , Callahan Thomas F. , Callahan Matthew G. , Jones James T. , Graber George P. , Foster Kirk S. , Glifort Kenneth , Wodicka George R.
Published: July 2002

Auscultation of lung sounds in patient transport vehicles such as an ambulance or aircraft is unachievable because of high ambient noise levels. Aircraft noise levels of 90–100 dB SPL are common, while lung sounds have been measured in the 22–30 dB SPL range in free space and 65–70 dB SPL within a stethoscope coupler. Also, the bandwidth of lung sounds and vehicle noise typically has significant overlap, limiting the utility of traditional band-pass filtering. In this study, a passively shielded stethoscope coupler that contains one microphone to measure the (noise-corrupted) lung sounds and another to measure the ambient noise was constructed. Lung sound measurements were made on a healthy subject in a simulated USAF C-130 aircraft environment within an acoustic chamber at noise levels ranging from 80 to 100 dB SPL. Adaptive filtering schemes using a least-mean-squares (LMS) and a normalized least-mean-squares (NLMS) approach were employed to extract the lung sounds from the noise-corrupted signal. Approximately 15 dB of noise reduction over the 100–600 Hz frequency range was achieved with the LMS algorithm, with the more complex NLMS algorithm providing faster convergence and up to 5 dB of additional noise reduction. These findings indicate that a combination of active and passive noise reduction can be used to measure lung sounds in high noise environments.
Acoustic streaming near Albunex spheres
Authors: Gormley Gerard , Wu Junru
Published: July 2002

Acoustic streaming near bubbles in an external standing-wave sound field has been an interesting research topic for decades. It was relatively difficult to visualize the acoustic streaming pattern experimentally, especially for small bubbles due to the instability of the bubbles and difficulties associated with the optical technique. Using Albunex spheres (a contrast agent for ultrasonic imaging), a specially designed microscope device, and a video peak store technique, several acoustic streaming patterns around a single and a pair of Albunex spheres of tens of micrometers radius in a 160-kHz ultrasonic standing wave field have been recorded. Spatial peak pressure amplitude of the standing wave was estimated to be in the order of 0.5 MPa by using optical interferometry. The acoustic streaming velocity was in the range of 50–100 μ/s.
Examination of the two-dimensional pupil function in coherent scanning microscopes using spherical particles
Authors: Weise Wieland , Zinin Pavel , Briggs Andrew , Wilson Tony , Boseck Siegfried
Published: July 2002

The determination of the modulus of the pupil function in reflection acoustic and optical microscopy with the help of spherical particles is demonstrated. The theoretical examination shows that this method can give good results if the pupil function drops smoothly towards the edge. For a pupil with a sharp edge this technique can give the accurate pupil function only by imaging large spheres. The dependence of the accuracy of the method on the size of the spherical particle is analyzed. Numerical and experimental results obtained for the confocal scanning optical microscope and the scanning acoustic microscope are examined.
Generalized Bremmer series with rational approximation for the scattering of waves in inhomogeneous media
Authors: van Stralen Mattheus J. N. , de Hoop Maarten V. , Blok Hans
Published: July 2002

The Bremmer series solution of the wave equation in generally inhomogeneous media, requires the introduction of pseudodifferential operators. In this paper, sparse matrix representations of these pseudodifferential operators are derived. The authors focus on designing sparse matrices, keeping the accuracy high at the cost of ignoring any critical scattering-angle phenomena. Such matrix representations follow from rational approximations of the vertical slowness and the transverse Laplace operator symbols, and of the vertical derivative, as they appear in the parabolic equation method. Sparse matrix representations lead to a fast algorithm. An optimization procedure is followed to minimize the errors, in the high-frequency limit, for a given discretization rate. The Bremmer series solver consists of three steps: directional decomposition into up- and downgoing waves, one-way propagation, and interaction of the counterpropagating constituents. Each of these steps is represented by a sparse matrix equation. The resulting algorithm provides an improvement of the parabolic equation method, in particular for transient wave phenomena, and extends the latter method, systematically, for backscattered waves.
Unsteady dynamics and control of marine thrusters
Authors: Bachmayer Ralf , Whitcomb Louis
Published: July 2002

This paper reports advances in the unsteady dynamical modeling and control of marine thrusters. First, recent advances in finite-dimensional nonlinear dynamical modeling of marine thrusters are reviewed [Healey et al., IEEE J. Oceanic Eng. 20(4), 354–361 (1995); Bacmayer et al., IEEE/MTS Oceans’98]. Second, a novel nonlinear model-based control algorithm is presented. Third, the performance of the nonlinear model-based control algorithm is evaluated in comparison with conventional and previously reported thrust control algorithms [Whitcomb and Yoerger, IEEE/MTS Oceans’95 2, 1019–1028 (1995)]. [Work supported by NSF and ONR.]
Effects of stimulation mode on threshold and loudness growth in multielectrode cochlear implants
Authors: Chatterjee Monita
Published: July 2002

The effect of increasing the separation between the two members of a stimulating electrode pair was studied in four users of the Nucleus-22 cochlear implant. Two experiments were performed. In experiment 1, detection threshold for a 200-ms, 500-pulses/s biphasic pulse train was measured as the spatial separation between the active and return electrodes was increased. In experiment 2, loudness-growth functions were measured as the electrode separation was increased. The results of experiment 1 indicate that (a) threshold decreases monotonically toward an asymptote (monopolar threshold) as the electrode separation is increased and (b) the threshold versus electrode separation function is similar across subjects and electrode location. The results of experiment 2 indicate that loudness L is related to the current amplitude I by a simple exponential function: L=eβI, where β, the exponent of the loudness function, is, to a first approximation, linearly related to the separation between the electrodes of the stimulating pair. Thus, dynamic range and the shape of loudness growth can be directly linked to the spatial separation between active and return electrodes.
Nonlinear active force generation by cochlear outer hair cell
Authors: Spector Alexander A. , Brownell William E. , Popel Aleksander S.
Published: July 2002

We analyze the nonlinear behavior of the longitudinal and circumferential components of the active force generated by the outer hair cell wall in response to changes of its transmembrane potential. We treat the material of the wall as electroelastic, linear orthotropic in terms of strains and as nonlinear in terms of the transmembrane potential. To describe the nonlinear behavior of the active force versus the transmembrane potential, we use two (Boltzmann and simple exponential) types of approximation. We estimate free parameters of these approximations by combining the previously reported passive stiffnesses with the active strains measured in the microchamber experiment. We analyze the sensitivity of the estimated parameters corresponding to changes of the cell axial stiffness, a characteristic independently measured by several groups. We also study the effect of combining the active strains measured in the microchamber experiment with those measured in the whole cell recording experiment. We show agreement between our prediction of the active force and measurements in the whole cochlea and in isolated cells.
Medial efferent effects on auditory-nerve responses to tail-frequency tones. I. Rate reduction
Authors: Stankovic Konstantina M. , Guinan John J.
Published: July 2002

One way medial efferents are thought to inhibit responses of auditory-nerve fibers (ANFs) is by reducing the gain of the cochlear amplifier thereby reducing motion of the basilar membrane. If this is the only mechanism of medial efferent inhibition, then medial efferents would not be expected to inhibit responses where the cochlear amplifier has little effect, i.e., at sound frequencies in the tails of tuning curves. Inhibition at tail frequencies was tested for by obtaining randomized rate-level functions from cat ANFs with high characteristic frequencies (CF⩾5 kHz), stimulated with tones two or more octaves below CF. It was found that electrical stimulation of medial efferents can indeed inhibit ANF responses to tail-frequency tones. The amplitude of efferent inhibition depended on both sound level (largest near to threshold) and frequency (largest two to three octaves below CF). On average, inhibition of high-CF ANFs responding to 1 kHz tones was around 5 dB. Although an efferent reduction of basilar-membrane motion cannot be ruled out as the mechanism producing the inhibition of ANF responses to tail frequency tones, it seems more likely that efferents produce this effect by changing the micromechanics of the cochlear partition.
The contribution of static and dynamically varying ITDs and IIDs to binaural detection
Authors: Breebaart Jeroen , van de Par Steven , Kohlrausch Armin
Published: July 2002

This paper investigates the relative contribution of various interaural cues to binaural unmasking in conditions with an interaurally in-phase masker and an out-of-phase signal (MoSπ). By using a modified version of multiplied noise as the masker and a sinusoid as the signal, conditions with only interaural intensity differences (IIDs), only interaural time differences (ITDs), or combinations of the two were realized. In addition, the experimental procedure allowed the presentation of specific combinations of static and dynamically varying interaural differences. In these conditions with multiplied noise as masker, the interaural differences have a bimodal distribution with a minimum at zero IID or ITD. Additionally, by using the sinusoid as masker and the multiplied noise as signal, a unimodal distribution of the interaural differences was realized. Through this variation in the shape of the distributions, the close correspondence between the change in the interaural cross correlation and the size of the interaural differences is no longer found, in contrast to the situation for a Gaussian-noise masker [Domnitz and Colburn, J. Acoust. Soc. Am. 59, 598–601 (1976)]. When analyzing the mean thresholds across subjects, the experimental results could not be predicted from parameters of the distributions of the interaural differences (the mean, the standard deviation, or the root-mean-square value). A better description of the subjects’ performance was given by the change in the interaural correlation, but this measure failed in conditions which produced a static interaural intensity difference. The data could best be described by using the energy of the difference signal as the decision variable, an approach similar to that of the equalization and cancellation model.
Age differences in backward masking
Authors: Gehr Sara Elizabeth , Sommers Mitchell S.
Published: July 2002

The present study was designed to assess the effects of age on the time course of backward masking. In experiment 1, thresholds for detecting a 10-ms, 500-Hz sinusoidal signal were measured as a function of the temporal separation between the signal and a 50-ms broadband masker. Subjects were younger (18–24) and older (over age 65) adults with normal hearing (thresholds less than 20 dB HL) for frequencies of 4 kHz and below. Younger subjects exhibited less overall masking and steeper recovery functions than did the older adults. Masked thresholds for younger participants approached unmasked thresholds for signal-masker delays greater than 6–8 ms. In contrast, older adults exhibited significant masking even at the longest delay tested (20 ms). In experiment 2, signal duration was decreased to 5 ms for a separate group of younger adults. Although overall thresholds were elevated for the shorter signal duration, the slope of the backward masking recovery function was not different from that observed for younger adults in experiment 1. The results suggest that age, independent of hearing loss, affects the temporal course of backward masking.
The effects of frequency region and level on the temporal modulation transfer function
Authors: Strickland Elizabeth A.
Published: July 2002

Temporal modulation transfer functions (TMTFs) were measured using narrow-band AM and QFM noises with upper spectral edges from 0.6 to 4.8 kHz, and spectrum levels of 10 and 40 dB SPL. The cutoff frequency of the TMTF increases as the upper spectral edge is increased up to 4.8 kHz at low levels, and is constant at higher levels. Sensitivity increases with bandwidth if frequency region is constant. In a second experiment, these results were compared to predictions of a model incorporating peripheral and central limitations to modulation detection. To obtain an estimate of peripheral filtering, frequency selectivity was measured using the notched-noise method, with probe frequencies and levels chosen to parallel those in the first experiment. The TMTF data were then predicted using the model. Predicted cutoff frequencies as a function of the upper spectral edge of the test stimulus were lower than but parallel to those of the subjects at the lower stimulus level. The model predicted only a slight increase in cutoff frequency with level, and thus predicted an increase in cutoff frequency with frequency region at the higher level as well, in contrast to the measured data. These results suggest that there are peripheral and central limitations to temporal resolution, but the psychoacoustically derived auditory filter may be only an indirect measure of peripheral filtering, and/or a more complex model may be needed.
Experimental investigation of transient pressure waves produced in dielectric liquids
Authors: Jomni F. , Aitken F. , Denat A.
Published: July 2002

The experimental results reported in this paper mainly concern the two first transient pressure waves emitted after a fast (∼ns) and localized (∼μm) injection of electrical energy Wi in insulating liquids. The influence of various parameters (hydrostatic pressure P∞, injected energy Wi, etc.) on the relative amplitude of these two transient pressure waves are presented and discussed. The analysis shows clearly a difference of behavior, in particular their dependence as a function of hydrostatic pressure, between these two waves. Basically, the physical processes leading to their emission are quite different. The first pressure transient is a consequence of the plasma relaxation, whereas the second one is due to the bubble collapse. According to these results, the chronology of the events is more improved, as well as the theoretical analysis.
Use of higher order statistics in source signature estimation
Authors: Broadhead Michael K. , Pflug Lisa A. , Field Robert L.
Published: July 2002

Higher order statistical blind deconvolution methods are implemented for use in removing multipath distortion from passively received underwater acoustic transient signals. Using single channel data and simulations, it is demonstrated that a fourth order method based on cumulant maximization can work well if the associated multipath Green’s function is sufficiently “sparse.” The iterative method is parameterized by filter length, and while there is a range of values at which the best solutions are obtained with conventional convergence criteria, useful solutions exist across a much broader range of filter lengths if the iterations are not always allowed to proceed to convergence. The fourth order objective functional is generalized to arbitrary order, and the method is shown to also produce good results for the third order objective functional.
Chemorheology and the Mechanical Behavior of Vulcanized Rubbers
Authors: Fong Jeffrey T. , Zapas Louis J.
Published: July 2002

The objective of this work is to represent general nonlinear viscoelasticity by a model based on a modified two-network theory. As a basic problem we examine Neubert and Saunders' data (1958) on the permanent set of crosslinked natural rubber samples after heating in a state of pure shear or simple extension. It is evident that the preferred configuration changes with time of heating. Our approach is to associate the preferred configuration with an internal measure of length in an initially isotropic material which becomes anisotropic after heating in a deformed state. Using Ericksen and Rivlin's work (1954) on anisotropic materials and a strain energy function which reduces for isotropic materials to Rivlin and Saunders' function (1951), we show an excellent consistency with the Neubert and Saunders' data. We also show consistency with some more recent data due to Djiauw and Gent (1973).
The role of liquid-crystalline polymer rheology on the evolving morphology of immiscible blends containing liquid-crystalline polymers
Authors: Kernick William A. , Wagner Norman J.
Published: July 2002

A new method is demonstrated that applies the Porod limit of small angle neutron scattering to measure the interface morphology in concentrated, immiscible blends in situ under simple shear. The effect of viscoelastic contrast on rheology and blend microstructure is probed for a model dispersion of liquid crystalline polymer dispersed in a linear polymer matrix. Comparison to theories demonstrates the complex morphology evolution is a consequence of the unique rheology of liquid crystalline polymers. The results at low shear rates are used to predict the onset of stable microfibrillation at higher shear rates through consideration of the contrast in first normal stress differences.
Health Status and Health Care Access Among Lesbian, Gay, and Bisexual Adults in the US, 2013 to 2018
Authors: Liu Michael , Sandhu Sahil , Reisner Sari L. , Gonzales Gilbert , Keuroghlian Alex S.
Published: February 2023

This cross-sectional study evaluated data from a large US survey (2013-2018) to determine how health status and access have changed among lesbian, gay, and bisexual adults compared with heterosexual counterparts.
Safely Prescribing Nirmatrelvir and Ritonavir—Avoiding Drug-Drug Interactions
Authors: Culas Roshni , Nath Sridesh , Nath Sarath
Published: February 2023

This Teachable Moment discusses drug-drug interactions with nirmatrelvir and ritonavir (Paxlovid) treatment for COVID-19 and considerations when prescribing.
Bibrachial Amyotrophy Due to Spontaneous Spinal Cerebrospinal Fluid Leak
Authors: Schievink Wouter I. , Maya Marcel M.
Published: February 2023

This case report describes a patient with bibrachial amyotrophy due to spontaneous spinal cerebrospinal fluid leak.
Tough Transient Ionic Junctions Printed with Ionic Microgels
Authors: Huo Ran , Bao Guangyu , He Zixin , Li Xuan , Ma Zhenwei , Yang Zhen , Moakhar Roozbeh , Jiang Shuaibing , Chung‐Tze‐Cheong Christopher , Nottegar Alexander , Cao Changhong , Mahshid Sara , Li Jianyu
Published: February 2023

Emerging soft ionotronics better match the human body mechanically and electrically compared to conventional rigid electronics. They hold great potential for human‐machine interfaces, wearable and implantable devices, and soft machines. Among various ionotronic devices, ionic junctions play critical roles in rectifying currents as electrical p–n junctions. Existing ionic junctions, however, are limited in electrical and mechanical performance, and are difficult to fabricate and degrade. Herein, the design, fabrication, and characterization of tough transient ionic junctions fabricated via 3D ionic microgel printing is reported. The 3D printing method demonstrates excellent printability and allows one to fabricate ionic junctions of various configurations with high fidelity. By combining ionic microgels, degradable networks, and highly charged biopolymers, the ionic junctions feature high stretchability (stretch limit 27), high fracture energy (>1000 Jm−2), excellent electrical performance (current rectification ratio >100), and transient stability (degrade in 1 week). A variety of ionotronic devices, including ionic diodes, ionic bipolar junction transistors, ionic full‐wave rectifiers, and ionic touchpads are further demonstrated. This study merges ionotronics, 3D printing, and degradable hydrogels, and will motivate the future development of high‐performance transient ionotronics.
Water‐Stable CsPbBr3/Reduced Graphene Oxide Nanoscrolls for High‐Performance Photoelectrochemical Sensing
Authors: Mao Lebao , Xiao Yao , Liu Hao , Zhang Xiuhua , Wang Shengfu , Huang Wei‐Hua , Chen Miao‐Miao
Published: February 2023

Perovskite quantum dots (PQDs) have attracted much attention in the field of photoelectrochemical (PEC) sensors owing to their superb optical properties and efficient charge transport, but the inherent poor stability severely hinders their PEC applications. Herein, hydrolysis‐resistant CsPbBr3/reduced graphene oxide nanoscrolls (CsPbBr3/rGO NSs) are obtained by solvent‐assisted self‐rolling process toward water‐stable PEC sensors. CsPbBr3 QDs embedded in rGO nanosheets can be prevented from water since the multilayer rGO shell layers, which maintains excellent optical properties. On account of strong interfacial interactions, rGO nanosheets are crimped spontaneously with CsPbBr3 QDs, which offer access to superb structural and long‐term storage stability. Moreover, appropriate band alignment and ultrafast interfacial carrier transfer enable CsPbBr3/rGO NSs to exhibit greatly enhanced anode photocurrent response for subsequent PEC sensing. As a demonstration, the molecular imprinted PEC sensors for two kinds of mycotoxins (aflatoxin B1 or ochratoxin A) presents an ultra‐high sensitivity and good anti‐interference ability. Significantly, this work provides an inspirable and convenient route for hydrolysis‐resistant PQDs‐based optoelectronic and photoelectrocatalytic applications in aqueous ambience.
AgCuS: A Single Material Diode with Fast Switching Times
Authors: Deng Philipp , Rabenbauer Alfred , Vosseler Kathrin , Venturini Janio , Nilges Tom
Published: February 2023

Pnp‐switchable semiconductor materials are capable of switching their electronic properties from p‐ to n‐type conduction. Observed in the handful of discovered compounds, this behavior is usually accompanied by a temperature‐dependent phase transition. During this transition, the dynamical rearrangement of a certain substructure enables the change of the predominant charge carrier type. Considering the immense demand for compact and flexible electronic components, one possible approach is the construction of unconventional one‐compound diodes using these pnp‐switchable materials. In this study, pnp‐switchable AgCuS is applied to realize a functional one‐compound diode. AgCuS is accessible in large quantities as bulk material in a simple and short timeframe. Featuring an addressable pnp‐switch at 364 K, this material is suitable for diode generation and usage in varied applications. The diode properties of AgCuS devices are reported and illustrate its reversibility and flexibility for diode operation. The material is fully characterized with regards to its electrical and thermal properties, as well as its diode performance. Properties of AgCuS are discussed in relation to the pnp‐switchable material Ag18Cu3Te11Cl3, which is successfully used to fabricate the first one‐compound diode operating close to room temperature.
Voltage‐Modulated Untwist Deformations and Multispectral Optical Effects from Ion Intercalation into Chiral Ceramic Nanoparticles
Authors: Shao Xiao , Zhu Cheng , Kumar Prashant , Wang Yanan , Lu Jun , Cha Minjeong , Yao Lin , Cao Yuan , Mao Xiaoming , Heinz Hendrik , Kotov Nicholas A.
Published: February 2023

Reconfiguration of chiral ceramic nanostructures after ion intercalation should favor specific nanoscale twists leading to strong chiroptical effects.  In this work, V2O3 nanoparticles are shown to have “built‐in” chiral distortions caused by binding of tartaric acid enantiomers to the nanoparticle surface. As evidenced by spectroscopy/microscopy techniques and calculations of nanoscale chirality measures, the intercalation of Zn2+ ions into the V2O3 lattice results in particle expansion, untwist deformations, and chirality reduction. Coherent deformations in the particle ensemble manifest as changes in sign and positions of circular polarization bands at ultraviolet, visible, mid‐infrared (IR), near‐IR (NIR), and IR wavelengths. The g‐factors observed for IR and NIR spectral diapasons are ≈100–400 times higher than those for previously reported dielectric, semiconductor, and plasmonic nanoparticles. Nanocomposite films layer‐by‐layer assembled (LBL) from V2O3 nanoparticles reveal cyclic‐voltage‐driven modulation of optical activity. Device prototypes for IR and NIR range problematic for liquid crystals and other organic materials are demonstrated. High optical activity, synthetic simplicity, sustainable processability, and environmental robustness of the chiral LBL nanocomposites provide a versatile platform for photonic devices. Similar reconfigurations of particle shapes are expected for multiple chiral ceramic nanostructures, leading to unique optical, electrical, and magnetic properties.
Van der Waals Epitaxy Growth of 2D Single‐Element Room‐Temperature Ferromagnet
Authors: Jiang Jian , Cheng Ruiqing , Feng Wenyong , Yin Lei , Wen Yao , Wang Yanrong , Cai Yuchen , Liu Yong , Wang Hao , Zhai Baoxing , Liu Chuansheng , He Jun , Wang Zhenxing
Published: February 2023

2D single‐element materials, which are pure and intrinsically homogeneous on the nanometer scale, can cut the time‐consuming material‐optimization process and circumvent the impure phase, bringing about opportunities to explore new physics and applications. Herein, for the first time, the synthesis of ultrathin cobalt single‐crystalline nanosheets with a sub‐millimeter scale via van der Waals epitaxy is demonstrated. The thickness can be as low as ≈6 nm. Theoretical calculations reveal their intrinsic ferromagnetic nature and epitaxial mechanism: that is, the synergistic effect between van der Waals interactions and surface energy minimization dominates the growth process. Cobalt nanosheets exhibit ultrahigh blocking temperatures above 710 K and in‐plane magnetic anisotropy. Electrical transport measurements further reveal that cobalt nanosheets have significant magnetoresistance (MR) effect, and can realize a unique coexistence of positive MR and negative MR under different magnetic field configurations, which can be attributed to the competition and cooperation effect among ferromagnetic interaction, orbital scattering, and electronic correlation. These results provide a valuable case for synthesizing 2D elementary metal crystals with pure phase and room‐temperature ferromagnetism and pave the way for investigating new physics and related applications in spintronics.
Diagnosing and Correcting the Failure of the Solid‐State Polymer Electrolyte for Enhancing Solid‐State Lithium–Sulfur Batteries
Authors: Meng Xiangyu , Liu Yuzhao , Ma Yanfu , Boyjoo Yash , Liu Jian , Qiu Jieshan , Wang Zhiyu
Published: February 2023

Solid‐state polymer electrolytes (SPEs) attract great interest in developing high‐performance yet reliable solid‐state batteries. However, understanding of the failure mechanism of the SPE and SPE‐based solid‐state batteries remains in its infancy, posing a great barrier to practical solid‐state batteries. Herein, the high accumulation and clogging of “dead” lithium polysulfides (LiPS) on the interface between the cathode and SPE with intrinsic diffusion limitation is identified as a critical failure cause of SPE‐based solid‐state Li–S batteries. It induces a poorly reversible chemical environment with retarded kinetics on the cathode–SPE interface and in bulk SPEs, starving the Li–S redox in solid‐state cells. This observation is different from the case in liquid electrolytes with free solvent and charge carriers, where LiPS dissolve but remain alive for electrochemical/chemical redox without interfacial clogging. Electrocatalysis demonstrates the feasibility of tailoring the chemical environment in diffusion‐restricted reaction media for reducing Li–S redox failure in the SPE. It enables Ah‐level solid‐state Li–S pouch cells with a high specific energy of 343 Wh kg−1 on the cell level. This work may shed new light on the understanding of the failure mechanism of SPE for bottom‐up improvement of solid‐state Li–S batteries.