bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of coupled vibrations on the acoustical performance of underwater cylindrical shell transducers
Authors: Aronov Boris , Brown David A. , Bachand Corey L.
Published: February 2008

An experimental investigation of the effects of coupled vibrations on the acoustical performance of underwater transducers made from radially polarized, thin walled, air-backed, piezoelectric cylinders as a function of their height-to-diameter aspect ratio is presented. Characteristics of the frequency response, directivity patterns, and effectiveness of the transducers are considered in comparison with analogous characteristics for the transducers comprised of mechanically separated rings, otherwise having the same geometry. Recommendations are made on the application of cylindrical piezoelectric elements with different aspect ratios for underwater transducer applications.
Full wave-field reflection coefficient inversion
Authors: Dettmer Jan , Dosso Stan E. , Holland Charles W.
Published: February 2008

This paper develops a Bayesian inversion for recovering multilayer geoacoustic (velocity, density, attenuation) profiles from a full wave-field (spherical-wave) seabed reflection response. The reflection data originate from acoustic time series windowed for a single bottom interaction, which are processed to yield reflection coefficient data as a function of frequency and angle. Replica data for inversion are computed using a wave number-integration model to calculate the full complex acoustic pressure field, which is processed to produce a commensurate seabed response function. To address the high computational cost of calculating short range acoustic fields, the inversion algorithms are parallelized and frequency averaging is replaced by range averaging in the forward model. The posterior probability density is interpreted in terms of optimal parameter estimates, marginal distributions, and credibility intervals. Inversion results for the full wave-field seabed response are compared to those obtained using plane-wave reflection coefficients. A realistic synthetic study indicates that the plane-wave assumption can fail, producing erroneous results with misleading uncertainty bounds, whereas excellent results are obtained with the full-wave reflection inversion.
Effect of auditory-nerve response variability on estimates of tuning curves
Authors: Chintanpalli Ananthakrishna , Heinz Michael G.
Published: February 2008

Near-Poisson variability in auditory-nerve (AN) responses limits the accuracy of automated tuning-curve algorithms. Here, a typical adaptive tuning-curve algorithm was used with a physiologically realistic AN model with and without the inclusion of neural randomness. Response randomness produced variability in Q10 estimates that was nearly as large as in AN data. Results suggest that it is sufficient for AN models to specify frequency selectivity based on mean Q10 values at each characteristic frequency (CF). Errors in estimates of CF, which decreased from ±0.2 octaves at low frequencies to ±0.05 octaves at high frequencies, are significant for studies of spatiotemporal coding.
Distortion product otoacoustic emissions: Cochlear-source contributions and clinical test performance
Authors: Johnson Tiffany A. , Neely Stephen T. , Kopun Judy G. , Dierking Darcia M. , Tan Hongyang , Converse Connie , Kennedy Elizabeth , Gorga Michael P.
Published: February 2008

It has been proposed that the clinical accuracy of distortion product otoacoustic emissions (DPOAEs) is affected by the interaction of distortion and reflection sources contributing to the response. This study evaluated changes in dichotomous-decision test performance and threshold-prediction accuracy when DPOAE source contribution was controlled. Data were obtained from 205 normal and impaired ears with L2 ranging from 0 to 80dB SPL and f2=2 and 4kHz. Data were collected for control conditions (no suppressor, f3) and with f3 presented at three levels that previously had been shown to reduce the reflection-source contribution. The results indicated that controlling source contribution with a suppressor did not improve diagnostic accuracy (as reflected by relative operating characteristic curve area) and frequently resulted in poorer test performance compared to control conditions. Likewise, correlations between DPOAE and behavioral thresholds were not strengthened when using the suppressors to control source contribution. While improvements in test accuracy were observed for a subset of subjects (normal ears with the smallest DPOAEs and impaired ears with the largest DPOAEs), the lack of improvement for the larger, unselected subject group suggests that DPOAEs should be recorded in the clinic without attempting to control the source contribution with a suppressor.
Perceptual thresholds for detecting modifications applied to the acoustical properties of a violin
Authors: Fritz Claudia , Cross Ian , Moore Brian C. J. , Woodhouse Jim
Published: February 2008

This study is the first step in the psychoacoustic exploration of perceptual differences between the sounds of different violins. A method was used which enabled the same performance to be replayed on different “virtual violins,” so that the relationships between acoustical characteristics of violins and perceived qualities could be explored. Recordings of real performances were made using a bridge-mounted force transducer, giving an accurate representation of the signal from the violin string. These were then played through filters corresponding to the admittance curves of different violins. Initially, limits of listener performance in detecting changes in acoustical characteristics were characterized. These consisted of shifts in frequency or increases in amplitude of single modes or frequency bands that have been proposed previously to be significant in the perception of violin sound quality. Thresholds were significantly lower for musically trained than for nontrained subjects but were not significantly affected by the violin used as a baseline. Thresholds for the musicians typically ranged from 3to6dB for amplitude changes and 1.5%–20% for frequency changes. Interpretation of the results using excitation patterns showed that thresholds for the best subjects were quite well predicted by a multichannel model based on optimal processing.
Environmental inversion using high-resolution matched-field processing
Authors: Soares Cristiano , Jesus Sérgio M. , Coelho Emanuel
Published: February 2008

This paper considers the inversion of experimental field data collected with light receiving systems designed to meet operational requirements. Such operational requirements include system deployment in free drifting configurations and a limited number of acoustic receivers. A well-known consequence of a reduced spatial coverage is a poor sampling of the vertical structure of the acoustic field, leading to a severe ill-conditioning of the inverse problem and data to model cost function with a massive sidelobe structure having many local extrema. This causes difficulties to meta-heuristic global search methods, such as genetic algorithms, to converge to the true model parameters. In order to cope with this difficulty, broadband high-resolution processors are proposed for their ability to significantly attenuate sidelobes, as a contribution for improving convergence. A comparative study on simulated data shows that high-resolution methods did not outperform the conventional Bartlett processor for pinpointing the true environmental parameter when using exhaustive search. However, when a meta-heuristic technique is applied for exploring a large multidimensional search space, high-resolution methods clearly improved convergence, therefore reducing the inherent uncertainty on the final estimate. These findings are supported by the results obtained on experimental field data obtained during the Maritime Rapid Environmental Assessment 2003 sea trial.
Accelerometer measurements of acoustic-to-seismic coupling above buried objects
Authors: Attenborough Keith , Qin Qin , Jefferis Jonathan , Heald Gary
Published: February 2008

The surface velocity of sand inside a large PVC container, induced by the sound pressure from either a large loudspeaker radiating into an inverted cone and pipe or a Bruel and Kjaer point source loudspeaker mounted with its axis vertical, has been measured using accelerometers. Results of white noise and stepped frequency excitation are presented. Without any buried object the mass loading of an accelerometer creates resonances in the spectral ratio of sand surface velocity to incident acoustic pressure, i.e., the acoustic-to-seismic (A/S) admittance spectra. The A/S responses above a buried compliant object are larger and distinctive. The linear A/S admittance spectra in the presence of a buried electronic components box have been studied as a function of burial depth and sand state. The nonlinear responses above the buried box have been studied as a function of depth, sand state, and amplitude. Predictions of a modified one-dimensional lumped parameter model have been found to be consistent with the observed nonlinear responses. Also the modified model has been used to explain features of the A/S responses observed when using an accelerometer without any buried object.
Assessing a dual-frequency identification sonars’ fish-counting accuracy, precision, and turbid river range capability
Authors: Maxwell Suzanne L. , Gove Nancy E.
Published: February 2008

Accurately assessing migrating salmon populations in turbid rivers with hydroacoustics is challenging. Using single, dual, or split-beam sonars, difficulties occur fitting acoustic beams between the river’s narrow boundaries, distinguishing fish from nonfish echoes, and resolving individual fish at high densities. To address these issues, the fish-counting capability of a dual-frequency identification sonar (DIDSON), which produces high resolution, video-like images, was assessed. In a clear river, fish counts generated from a DIDSON, an echo counter, split-beam sonar, and video were compared to visual counts from a tower, a method frequently used to ground-truth sonars. The DIDSON and tower counts were very similar and showed the strongest agreement and least variability compared to the other methods. In a highly turbid river, the DIDSON’s maximum detection range for a 10.16cm spherical target was 17m, less than absorption and wave spreading losses predict, and 26m in clear water. Unlike tower and video methods, the DIDSON was not limited by surface disturbances or turbidity. DIDSON advantages over other sonars include: better target resolution; wider viewing angle; better coverage of the water column; accurate direction of travel; and simpler to aim and operate.
Negative axial radiation forces on solid spheres and shells in a Bessel beam
Authors: Marston Philip L.
Published: February 2008

Prior computations predict that fluid spheres illuminated by an acoustic Bessel beam can be subjected to a radiation force directed opposite the direction of beam propagation. The prediction of negative acoustic radiation force is extended to the cases of a solid poly(methylmethacrylate) PMMA sphere in water and an empty aluminum spherical shell in water. Compared with the angular scattering patterns for plane wave illumination, the scattering into the back hemisphere is suppressed when the radiation force is negative. This investigation may be helpful in the development of acoustic tweezers and in the development of methods for manipulating objects during space flight.
Optimal illumination and wave form design for imaging in random media
Authors: Borcea Liliana , Papanicolaou George , Tsogka Chrysoula
Published: February 2008

The problem of optimal illumination for selective array imaging of small and not well separated scatterers in clutter is considered. The imaging algorithms introduced are based on the coherent interferometric (CINT) imaging functional, which can be viewed as a smoothed version of travel-time migration. The smoothing gives statistical stability to the image but it also causes blurring. The trade-off between statistical stability and blurring is optimized with an adaptive version of CINT. The algorithm for optimal illumination and for selective array imaging uses CINT. It is a constrained optimization problem that is based on the quality of the image obtained with adaptive CINT. The resulting optimal illuminations and selectivity improve the resolution of the images significantly, as can be seen in the numerical simulations presented in the paper.
Resonant generation of surface acoustic waves between moving and stationary piezoelectric crystals
Authors: Khudik Vladimir N. , Theodosiou Constantine E.
Published: February 2008

The propagation of surface acoustic waves in a system composed of two piezoelectric crystals moving with respect to each other and separated by a vacuum gap is considered. The waves are localized on different sides of the gap and coupled only through the electrostatic interaction. It is shown that when the velocity of the relative motion of crystals is close to some value, there occurs a wave instability resulting in a resonant generation of these surface waves. The rate of growth of Bleustein–Gulyaev waves in piezoelectric crystals of 6mm symmetry class is determined analytically.
On appropriate equivalent monopole sets for rigid body scattering problems
Authors: Gounot Yves J. R. , Musafir Ricardo E.
Published: February 2008

The present paper investigates properties of the solutions obtained with the equivalent sources method in scattering problems with the aim of identifying suitable monopole arrangements. Simple geometry scatterers—parallelepipeds with different aspect ratios—are considered and easy-to-implement source supports are tested: linear, circular, elliptical, and a “double linear” one. It was found that the supports providing best solutions differ according to the body geometry and the incidence angle of the impinging wave. Moreover, in the situations in which the other supports fail, it is shown that the double linear one provides satisfactory solutions with a minimum number of monopoles. Rules that furnish appropriate numbers of sources to use as well as their positioning are given for the different cases. A simple procedure based on these rules is proposed for scatterers with a more complex geometry, guaranteeing, still with a low number of monopoles, solutions with satisfactory accuracy.
On the perception of similarity among talkers
Authors: Remez Robert E. , Fellowes Jennifer M. , Nagel Dalia S.
Published: February 2008

A listener who recognizes a talker notices characteristic attributes of the talker’s speech despite the novelty of each utterance. Accounts of talker perception have often presumed that consistent aspects of an individual’s speech, termed indexical properties, are ascribable to a talker’s unique anatomy or consistent vocal posture distinct from acoustic correlates of phonetic contrasts. Accordingly, the perception of a talker is acknowledged to occur independently of the perception of a linguistic message. Alternatively, some studies suggest that attention to attributes of a talker includes indexical linguistic attributes conveyed in the articulation of consonants and vowels. This investigation sought direct evidence of attention to phonetic attributes of speech in perceiving talkers. Natural samples and sinewave replicas derived from them were used in three experiments assessing the perceptual properties of natural and sine-wave sentences; of temporally veridical and reversed natural and sine-wave sentences; and of an acoustic correlate of vocal tract scale to judgments of sine-wave talker similarity. The results revealed that the subjective similarity of individual talkers is preserved in the absence of natural vocal quality; and that local phonetic segmental attributes as well as global characteristics of speech can be exploited when listeners notice characteristics of talkers.
Reconstruction of Rayleigh–Lamb dispersion spectrum based on noise obtained from an air-jet forcing
Authors: Larose Eric , Roux Philippe , Campillo Michel
Published: February 2008

The time-domain cross correlation of incoherent and random noise recorded by a series of passive sensors contains the impulse response of the medium between these sensors. By using noise generated by a can of compressed air sprayed on the surface of a plexiglass plate, we are able to reconstruct not only the time of flight but the whole wave forms between the sensors. From the reconstruction of the direct A0 and S0 waves, we derive the dispersion curves of the flexural waves, thus estimating the mechanical properties of the material without a conventional electromechanical source. The dense array of receivers employed here allow a precise frequency-wavenumber study of flexural waves, along with a thorough evaluation of the rate of convergence of the correlation with respect to the record length, the frequency, and the distance between the receivers. The reconstruction of the actual amplitude and attenuation of the impulse response is also addressed in this paper.
Generating sensor signals in isotropic noise fields
Authors: Habets Emanuël A. P. , Gannot Sharon
Published: February 2008

Researchers in the signal processing community often require sensor signals that result from a spherically or cylindrically isotropic noise field for simulation purposes. Although it has been shown that these signals can be generated using a number of uncorrelated noise sources that are uniformly spaced on a sphere or cylinder, this method is seldom used in practice. In this paper algorithms that generate sensor signals of an arbitrary one- and three-dimensional array that result from a spherically or cylindrically isotropic noise field are developed. Furthermore, the influence of the number of noise sources on the accuracy of the generated sensor signals is investigated.
Effects of perturbation magnitude and voice F level on the pitch-shift reflex
Authors: Liu Hanjun , Larson Charles R.
Published: February 2008

The purpose of the present study was to investigate the responsiveness of the pitch-shift reflex to small magnitude stimuli and voice fundamental frequency (F0) level. English speakers received pitch-shifted voice feedback (±10, 20, 30, 40, and 50cents, 200ms duration) during vowel phonations at a high and a low F0 level. Mean pitch-shift response magnitude increased as a function of pitch-shift stimulus magnitude, but when expressed as a percent of stimulus magnitude, declined from 100% with ±10cents to 37% with ±50cents stimuli. Response magnitudes were larger and latencies were shorter with a high F0 level (16cents;130ms) compared to a low F0 level (13cents;152ms). Data from the present study demonstrate that vocal response magnitudes are equal to small perturbation magnitudes, and they are larger and faster with a high F0 voice. These results suggest that the audio-vocal system is optimally suited for compensating for small pitch rather than larger perturbations. Data also suggest the sensitivity of the audio-vocal system to voice perturbation may vary with F0 level.
Comments on the limp frame equivalent fluid model for porous media
Authors: Panneton Raymond
Published: February 2008

In this letter, the low and high frequency limits of the effective density characterizing a limp frame porous medium are investigated. These theoretical limits are compared to the ones found for a classical rigid frame porous medium, and to experimental measurements. While the high frequency asymptotic behaviors of both limp and rigid effective densities are usually only slightly different, their low frequency behaviors are significantly different. Compared to experimental measurements performed on a limp frame fibrous layer, only the limp frame effective density yields good correlations over the whole frequency range.
Acoustic cues to lexical segmentation: A study of resynthesized speech
Authors: Spitzer Stephanie M. , Liss Julie M. , Mattys Sven L.
Published: February 2008

It has been posited that the role of prosody in lexical segmentation is elevated when the speech signal is degraded or unreliable. Using predictions from Cutler and Norris’ [J. Exp. Psychol. Hum. Percept. Perform. 14, 113–121 (1988)] metrical segmentation strategy hypothesis as a framework, this investigation examined how individual suprasegmental and segmental cues to syllabic stress contribute differentially to the recognition of strong and weak syllables for the purpose of lexical segmentation. Syllabic contrastivity was reduced in resynthesized phrases by systematically (i) flattening the fundamental frequency (F0) contours, (ii) equalizing vowel durations, (iii) weakening strong vowels, (iv) combining the two suprasegmental cues, i.e., F0 and duration, and (v) combining the manipulation of all cues. Results indicated that, despite similar decrements in overall intelligibility, F0 flattening and the weakening of strong vowels had a greater impact on lexical segmentation than did equalizing vowel duration. Both combined-cue conditions resulted in greater decrements in intelligibility, but with no additional negative impact on lexical segmentation. The results support the notion of F0 variation and vowel quality as primary conduits for stress-based segmentation and suggest that the effectiveness of stress-based segmentation with degraded speech must be investigated relative to the suprasegmental and segmental impoverishments occasioned by each particular degradation.
The effect of word learning on the perception of non-native consonant sequences
Authors: Davidson Lisa , Shaw Jason , Adams Tuuli
Published: February 2008

Previous research in cross-language perception has shown that non-native listeners often assimilate both single phonemes and phonotactic sequences to native language categories. This study examined whether associating meaning with words containing non-native phonotactics assists listeners in distinguishing the non-native sequences from native ones. In the first experiment, American English listeners learned word-picture pairings including words that contained a phonological contrast between CC and CVC sequences, but which were not minimal pairs (e.g., [ftake], [fətalu]). In the second experiment, the word-picture pairings specifically consisted of minimal pairs (e.g., [ftake], [fətake]). Results showed that the ability to learn non-native CC was significantly improved when listeners learned minimal pairs as opposed to phonological contrast alone. Subsequent investigation of individual listeners revealed that there are both high and low performing participants, where the high performers were much more capable of learning the contrast between native and non-native words. Implications of these findings for second language lexical representations and loanword adaptation are discussed.
Asphericity in Supernova Explosions from Late-Time Spectroscopy
Authors: Maeda Keiichi , Kawabata Koji , Mazzali Paolo A. , Tanaka Masaomi , Valenti Stefano , Nomoto Ken'ichi , Hattori Takashi , Deng Jinsong , Pian Elena , Taubenberger Stefan , Iye Masanori , Matheson Thomas , Filippenko Alexei V. , Aoki Kentaro , Kosugi George , Ohyama Youichi , Sasaki Toshiyuki , Takata Tadafumi
Published: February 2008

Core-collapse supernovae (CC-SNe) are the explosions that announce the death of massive stars. Some CC-SNe are linked to long-duration gamma-ray bursts (GRBs) and are highly aspherical. One important question is to what extent asphericity is common to all CC-SNe. Here we present late-time spectra for a number of CC-SNe from stripped-envelope stars and use them to explore any asphericity generated in the inner part of the exploding star, near the site of collapse. A range of oxygen emission-line profiles is observed, including a high incidence of double-peaked profiles, a distinct signature of an aspherical explosion. Our results suggest that all CC-SNe from stripped-envelope stars are aspherical explosions and that SNe accompanied by GRBs exhibit the highest degree of asphericity.
High-Resolution Mapping of Crossovers Reveals Extensive Variation in Fine-Scale Recombination Patterns Among Humans
Authors: Coop Graham , Wen Xiaoquan , Ober Carole , Pritchard Jonathan K. , Przeworski Molly
Published: February 2008

Recombination plays a crucial role in meiosis, ensuring the proper segregation of chromosomes. Recent linkage disequilibrium (LD) and sperm-typing studies suggest that recombination rates vary tremendously across the human genome, with most events occurring in narrow “hotspots.” To examine variation in fine-scale recombination patterns among individuals, we used dense, genome-wide single-nucleotide polymorphism data collected in nuclear families to localize crossovers with high spatial resolution. This analysis revealed that overall recombination hotspot usage is similar in males and females, with individual hotspots often active in both sexes. Across the genome, roughly 60% of crossovers occurred in hotspots inferred from LD studies. Notably, however, we found extensive and heritable variation among both males and females in the proportion of crossovers occurring in these hotspots.
A systematic review of epidemiological studies investigating risk factors for work-related road traffic crashes and injuries: Table 1
Authors: Robb G , Sultana S , Ameratunga S , Jackson R
Published: February 2008

Objective:

To critically appraise the published evidence for risk factors for injuries and deaths relating to work-related road traffic crashes.

Design:

Systematic review.

Data sources:

Electronic databases searched included Medline, EMBASE, PsycINFO, Transport database, and the Australian Transport and Road Index (ATRI) database. Additional searches included websites of relevant organizations, reference lists of included studies, and issues of major injury journals published within the past 5 years.

Inclusion criteria:

Studies were included if they investigated work-related traffic crashes or related injuries or deaths as the outcome, measured any potential risk factor for work-related road traffic crash as an exposure, included a relevant comparison group, and were written in English.

Methods:

Included studies were critically appraised using the GATE-lite critical appraisal form (www.epiq.co.nz). Meta-analysis was not attempted because of the heterogeneity of the included studies.

Findings:

Of 25 studies identified, three of four robust (case–control and case-crossover) studies found an increased injury risk (i) among workers after extended shifts, (ii) for tractor-trailers with brake and steering defects, and (iii) for “double configuration” trucks. The fourth study showed that alcohol and drug use were not risk factors in an industry with a random testing policy. The best cross-sectional studies showed associations between injury and sleepiness, time spent driving, occupational stress, non-insulin-dependent uncomplicated diabetes, and use of narcotics and antihistamines.

Conclusions:

Modifiable behavioral and vehicle-related risk factors are likely to contribute to work-related traffic injury. Fatigue and sleepiness—the most commonly researched topics—were consistently associated with increased risk.
Factors associated with hip protector adherence among older people in residential care
Authors: Cryer C , Knox A , Stevenson E
Published: February 2008

Background:

There is evidence to suggest that hip protectors (HPs) prevent fractures among older people living in nursing homes. Studies have found HP wearing rates (adherence) to be low.

Objectives:

To investigate factors that are associated with adherence and whether those factors account for the variation in adherence between residential care homes (RCHs).

Design:

Six-month prospective study.

Subjects and Setting:

299 people aged 65 years and over (80% female, mean age 86 years) living in 17 RCHs. 128 of these wore HPs at least once.

Methods:

All residents in the homes were offered three pairs of SAFEHIP HPs, and adherence was measured using diaries completed daily. A mixed model regression analysis was used to investigate predictive factors for wearing HPs and the effects of these factors on the between-home variability in adherence.

Results:

Increased HP adherence was associated with hypertension, incontinence, a previous history of falls and fractures, and hip fracture history in the RCH. Decreased adherence was associated with arthritis of the lower limbs and dizziness on first rising. The large variation in adherence between RCHs was almost completely explained by these factors.

Discussion:

The evidence for the efficacy of HPs is weakening. Low adherence compromises the power of trials to detect a real effect. The literature is inconsistent regarding what factors are associated with adherence. Nevertheless, it suggests that some people who are at increased risk of fracture are more likely to wear HPs. Variations in staff or resident knowledge and attitude towards HPs may explain some variation between homes.
Novel empirical disability weights to assess the burden of non-fatal injury
Authors: Haagsma J A , van Beeck E F , Polinder S , Hoeymans N , Mulder S , Bonsel G J
Published: February 2008

Background:

Disability weights are necessary to estimate the disability component (years lived with disability, YLDs) of disability-adjusted life years. The original global burden of disease approach to deriving disability weights ignores temporary consequences of injury.

Objectives:

To develop and apply novel empirical disability weights to improve estimates of the non-fatal burden of injury.

Methods:

A set of 45 disability weights was derived for both permanent and temporary consequences of injury, using the annual profile approach. A population panel (n = 143) provided the values. The novel set of disability weights was then linked to epidemiological surveillance data on the incidence of injury in The Netherlands to calculate YLD resulting from permanent and temporary consequences of injury.

Results:

The empirical disability weights for injury consequences varied from minor (corneal abrasion, 0.004) to very severe (quadriplegia, 0.719) health loss. Increasing disability weights by level of severity were found, as illustrated by concussion (0.02), versus moderate brain injury (0.193), versus severe brain injury (0.540). Application of these new disability weights showed a 36% increase in YLD as the result of unintentional injury.

Conclusions:

YLD calculations based on global burden of disease disability weights underestimate the size of the injury problem by ignoring temporary health consequences. Application of novel empirical disability weights, derived using the annual profile approach, may improve calculations on the burden of non-fatal injury.
When the rules of the game are broken: what proportion of high school sports-related injuries are related to illegal activity?
Authors: Collins C L , Fields S K , Comstock R D
Published: February 2008

Objectives:

To compare sport and gender differences in injury rates and proportions of injuries related to illegal activity and to describe the epidemiology of injuries related to illegal activity.

Design:

Descriptive epidemiology study.

Setting:

100 US high schools.

Subjects:

Athletes participating in nine sports: boys’ football, soccer, basketball, wrestling, and baseball plus girls’ soccer, volleyball, basketball, and softball.

Main outcome measures:

Illegal activity-related injuries were analyzed using data from the 2005–06 and 2006–07 National High School Sports-Related Injury Surveillance Study.

Results:

Nationally, an estimated 98 066 injuries were directly related to an action that was ruled illegal activity by a referee/official or disciplinary committee, giving an injury rate of 0.24 injuries per 1000 athletic competition-exposures. Boys’ and girls’ soccer had the highest rates of injuries related to illegal activity, and girls’ volleyball, girls’ softball, and boys’ baseball had the lowest. Overall, 6.4% of all high school sports-related injuries were related to illegal activity, with the highest proportion in girls’ basketball (14.0%), girls’ soccer (11.9%), and boys’ soccer (11.4%). A greater proportion of injuries related to illegal activity were to the head/face (32.3%) and were concussions (25.4%) than injuries not related to illegal activity (13.8% (injury proportion ratio 2.35; 95% CI 1.82 to 3.04; p<0.001) and 10.9% (injury proportion ratio 2.35; 95% CI 1.71 to 3.22; p<0.001), respectively).

Conclusions:

Illegal activity is an overlooked risk factor for sports-related injury. Reducing illegal activity through enhanced enforcement of sports’ rules and targeted education about the dangers of illegal activity for players, coaches, and referees/officials may reduce sports-related injuries.
Accuracy of medical and ambulance record restraint and crash data information for child occupants
Authors: Bilston L E , Brown J
Published: February 2008

Objective:

To correlate the accuracy of information on children’s restraint usage and crash characteristics recorded with medical data using in-depth crash investigation. Restraint and crash information within the medical and ambulance records is often available, but information on the accuracy of this data is limited.

Methods:

Comparison of restraint and crash characteristic data from medical and ambulance records with that obtained from in-depth crash investigation studies, for a case series of child occupants aged 2–8 years involved in motor vehicle crashes.

Results:

When restraint type, seating position, impact severity, and impact direction data were recorded in either the medical record or ambulance records, it tended to be at least partially correct. However, incompleteness or absence of specifics of restraint use and crash information in the medical record (7–17%) was common. Ambulance records were often not available (39%), but this data was more often complete (78–100%) and accurate (52–89%), when available, possibly due to the use of a standardized pro-forma.

Conclusions:

Ambulance and hospital records data can provide information on restraint type and usage for child occupants in motor vehicle crashes, as well as crash information. The use of a standardized pro-forma may encourage more complete and accurate reporting of restraint and crash data.
Metallothionein is a crucial protective factor againstHelicobacter pylori-induced gastric erosive lesions in a mouse model
Authors: Mita Masaharu , Satoh Masahiko , Shimada Akinori , Okajima Mina , Azuma Sadahiro , Suzuki Junko S. , Sakabe Kou , Hara Shuntaro , Himeno Seiichiro
Published: February 2008

Infection with the gastric pathogen Helicobacter pylori ( H. pylori) causes chronic gastritis, peptic ulcer, and gastric adenocarcinoma. These diseases are associated with production of reactive oxygen species (ROS) from infiltrated macrophages and neutrophiles in inflammatory sites. Metallothionein (MT) is a low-molecular-weight, cysteine-rich protein that can act not only as a metal-binding protein, but also as a ROS scavenger. In the present study, we examined the role of MT in the protection against H. pylori-induced gastric injury using MT-null mice. Female MT-null and wild-type mice were challenged with H. pylori SS1 strain, and then histological changes were evaluated with the updated Sydney grading system at 17 and 21 wk after challenge. Although the colonization efficiency of H. pylori was essentially the same for MT-null and wild-type mice, the scores of activity of inflammatory cells were significantly higher in MT-null mice than in wild-type mice at 17 wk after challenge. Histopathological examination revealed erosive lesions accompanied by infiltration of inflammatory cells in the infected MT-null mice but not in wild-type mice. Furthermore, activation of NF-κB and expression of NF-κB-mediated chemokines such as macrophage inflammatory protein-1α and monocytes chemoattractant protein-1 in gastric cells were markedly higher in MT-null mice than in wild-type mice. These results suggest that MT in the gastric mucosa might play an important role in the protection against H. pylori-induced gastric ulceration.
Dietary soy protein inhibits DNA damage and cell survival of colon epithelial cells through attenuated expression of fatty acid synthase
Authors: Xiao Rijin , Su Ying , Simmen Rosalia C. M. , Simmen Frank A.
Published: February 2008

Dietary intake of soy protein decreases tumor incidence in rat models of chemically induced colon cancer. We hypothesized that decreased expression of fatty acid synthase (FASN) underlies, in part, the tumor-preventive effects of soy protein, since FASN overexpression characterizes early tumorigenesis. Here, we show that colonic FASN levels are reduced with dietary intake of soy protein isolate (SPI), compared with a control casein diet, in male Sprague-Dawley rats administered the colon carcinogen azoxymethane. SPI consumption resulted in decreased serum insulin levels and decreased azoxymethane-induced tumor suppressor p53 phosphorylation in colon crypt epithelium. To evaluate potential links between insulin and FASN leading to DNA damage, C2BBe1 colon epithelial cells, treated with insulin and/or the carcinogen N-nitroso- N-methylurea (NMU), were evaluated for DNA damage and apoptosis after transfection with control or FASN small interfering RNAs (siRNAs). While the numbers of DNA apurinic/apyrimidinic sites (biomarker of DNA damage) induced by NMU were unaffected by transfection of FASN siRNA, insulin induction of these sites was decreased with FASN knockdown. By contrast, NMU-induced apoptosis of C2BBe1, as well as intestinal epithelial cell (IEC)-6, was enhanced by transfected FASN siRNA. Increased FASN expression in IEC-6 cells by addition of liver X receptor agonist T0901317 did not affect apurinic/apyrimidinic site number, but enhanced cell killing by cerulenin, a FASN inhibitor. Moreover, insulin rescued NMU-treated cells from apoptosis in an FASN-dependent manner. Results suggest that dietary SPI, by decreasing circulating insulin levels and colon FASN expression, attenuates insulin-induced DNA damage and FASN-mediated anti-apoptosis during carcinogenesis, resulting in an overall reduced tumorigenic state.
Diastolic suction is impaired by bed rest: MRI tagging studies of diastolic untwisting
Authors: Dorfman Todd A. , Rosen Boaz D. , Perhonen Merja A. , Tillery Tommy , McColl Roddy , Peshock Ronald M. , Levine Benjamin D.
Published: February 2008

Bed rest deconditioning leads to physiological cardiac atrophy, which may compromise left ventricular (LV) filling during orthostatic stress by reducing diastolic untwisting and suction. To test this hypothesis, myocardial-tagged magnetic resonance imaging (MRI) was performed, and maximal untwisting rates of the endocardium, midwall, and epicardium were calculated by Harmonic Phase Analysis (HARP) before and after −6° head-down tilt bed rest for 18 days with ( n = 14) and without exercise training ( n = 10). LV mass and LV end-diastolic volume were measured using cine MRI. Exercise subjects cycled on a supine ergometer for 30 min, three times per day at 75% maximal heart rate (HR). After sedentary bed rest, there was a significant reduction in maximal untwisting rates of the midwall (−46.8 ± 14.3 to −35.4 ± 12.4 °/s; P = 0.04) where untwisting is most reliably measured, and to a lesser degree of certainty in the endocardium (−50.3 ± 13.8 to −40.1 ± 18.5 °/s; P = 0.09); the epicardium was unchanged. In contrast, when exercise was performed in bed, untwisting rates were enhanced at the endocardium (−48.4 ± 20.8 to −72.3 ± 22.3 °/ms; P = 0.05) and midwall (−39.2 ± 12.2 to −59.0 ± 19.6 °/s; P = 0.03). The differential response was significant between groups at the endocardium (interaction P = 0.02) and the midwall (interaction P = 0.004). LV mass decreased in the sedentary group (156.4 ± 30.3 to 149.5 ± 27.9 g; P = 0.07), but it increased slightly in the exercise-trained subjects (156.4 ± 34.3 to 162.3 ± 40.5 g; P = 0.16); (interaction P = 0.03). We conclude that diastolic untwisting is impaired following sedentary bed rest. However, exercise training in bed can prevent the physiological cardiac remodeling associated with bed rest and preserve or even enhance diastolic suction.
Prostate Stem Cell Antigen Vaccination Induces a Long-term Protective Immune Response against Prostate Cancer in the Absence of Autoimmunity
Authors: de la Luz Garcia-Hernandez Maria , Gray Andrew , Hubby Bolyn , Klinger Otto J. , Kast W. Martin
Published: February 2008

Prostate stem cell antigen (PSCA) is an attractive antigen to target using therapeutic vaccines because of its overexpression in prostate cancer, especially in metastatic tissues, and its limited expression in other organs. Our studies offer the first evidence that a PSCA-based vaccine can induce long-term protection against prostate cancer development in prostate cancer–prone transgenic adenocarcinoma mouse prostate (TRAMP) mice. Eight-week-old TRAMP mice displaying prostate intraepithelial neoplasia were vaccinated with a heterologous prime/boost strategy consisting of gene gun–delivered PSCA-cDNA followed by Venezuelan equine encephalitis virus replicons encoding PSCA. Our results show the induction of an immune response against a newly defined PSCA epitope that is mediated primarily by CD8 T cells. The prostates of PSCA-vaccinated mice were infiltrated by CD4-positive, CD8-positive, CD11b-positive, and CD11c-positive cells. Vaccination induced MHC class I expression and cytokine production [IFN-γ, tumor necrosis factor-α, interleukin 2 (IL-2), IL-4, and IL-5] within prostate tumors. This tumor microenvironment correlated with low Gleason scores and weak PSCA staining on tumor cells present in hyperplastic zones and in areas that contained focal and well-differentiated adenocarcinomas. PSCA-vaccinated TRAMP mice had a 90% survival rate at 12 months of age. In contrast, all control mice had succumbed to prostate cancer or had heavy tumor loads. Crucially, this long-term protective immune response was not associated with any measurable induction of autoimmunity. The possibility of inducing long-term protection against prostate cancer by vaccination at the earliest signs of its development has the potential to cause a dramatic paradigm shift in the treatment of this disease. [Cancer Res 2008;68(3):861–9]
CD43, but not P-Selectin Glycoprotein Ligand-1, Functions as an E-Selectin Counter-Receptor in Human Pre-B–Cell Leukemia NALL-1
Authors: Nonomura Chizu , Kikuchi Jiro , Kiyokawa Nobutaka , Ozaki Hidenori , Mitsunaga Kanae , Ando Hidenobu , Kanamori Akiko , Kannagi Reiji , Fujimoto Junichiro , Muroi Kazuo , Furukawa Yusuke , Nakamura Mitsuru
Published: February 2008

B-cell precursor acute lymphoblastic leukemia (BCP-ALL/B-precursor ALL) is characterized by a high rate of tissue infiltration. The mechanism of BCP-ALL cell extravasation is not fully understood. In the present study, we have investigated the major carrier of carbohydrate selectin ligands in the BCP-ALL cell line NALL-1 and its possible role in the extravascular infiltration of the leukemic cells. B-precursor ALL cell lines and clinical samples from patients with BCP-ALL essentially exhibited positive flow cytometric reactivity with E-selectin, and the reactivity was significantly diminished by O-sialoglycoprotein endopeptidase treatment in NALL-1 cells. B-precursor ALL cell lines adhered well to E-selectin but only very weakly to P-selectin with low-shear-force cell adhesion assay. Although BCP-ALL cell lines did not express the well-known core protein P-selectin glycoprotein ligand-1 (PSGL-1), a major proportion of the carbohydrate selectin ligand was carried by a sialomucin, CD43, in NALL-1 cells. Most clinical samples from patients with BCP-ALL exhibited a PSGL-1neg/low/CD43high phenotype. NALL-1 cells rolled well on E-selectin, but knockdown of CD43 on NALL-1 cells resulted in reduced rolling activity on E-selectin. In addition, the CD43 knockdown NALL-1 cells showed decreased tissue engraftment compared with the control cells when introduced into γ-irradiated immunodeficient mice. These results strongly suggest that CD43 but not PSGL-1 plays an important role in the extravascular infiltration of NALL-1 cells and that the degree of tissue engraftment of B-precursor ALL cells may be controlled by manipulating CD43 expression. [Cancer Res 2008;68(3):790–9]
Enhanced Activation of Epidermal Growth Factor Receptor Caused by Tumor-Derived E-Cadherin Mutations
Authors: Bremm Anja , Walch Axel , Fuchs Margit , Mages Jörg , Duyster Justus , Keller Gisela , Hermannstädter Christine , Becker Karl-Friedrich , Rauser Sandra , Langer Rupert , von Weyhern Claus Hann , Höfler Heinz , Luber Birgit
Published: February 2008

Mutations of the tumor suppressor E-cadherin and overexpression of the receptor tyrosine kinase epidermal growth factor receptor (EGFR) are among the most frequent genetic alterations associated with diffuse-type gastric carcinoma. Accumulating evidence suggests a functional relationship between E-cadherin and EGFR that regulates both proteins. We report that somatic mutation of E-cadherin is associated with increased activation of EGFR followed by enhanced recruitment of the downstream acting signaling components growth factor receptor binding protein 2 and Shc, and activation of Ras. Reduced complex formation of mutant E-cadherin — with an in frame deletion of exon 8 in the extracellular domain resulting in reduced adhesion and increased motility — with EGFR was observed compared with wild-type E-cadherin. We conclude that reduced binding of mutant E-cadherin to EGFR in a multicomponent complex or reduced stability of the complex may enhance EGFR surface motility, thereby facilitating EGFR dimerization and activation. Furthermore, reduced surface localization due to enhanced internalization of mutant E-cadherin compared with the wild-type protein was observed. The internalization of EGFR was decreased in response to epidermal growth factor stimulation in cells expressing mutant E-cadherin, suggesting that mutation of E-cadherin also influences the endocytosis of EGFR. Moreover, we show increased activation of EGFR in gastric carcinoma samples with mutant E-cadherin lacking exons 8 or 9. In summary, we describe activation of EGFR by mutant E-cadherin as a novel mechanism in tumor cells that explains the enhanced motility of tumor cells in the presence of an extracellular mutation of E-cadherin. [Cancer Res 2008;68(3):707–14]
Direct Evidence for Epithelial-Mesenchymal Transitions in Breast Cancer
Authors: Trimboli Anthony J. , Fukino Koichi , de Bruin Alain , Wei Guo , Shen Lei , Tanner Stephan M. , Creasap Nicholas , Rosol Thomas J. , Robinson Michael L. , Eng Charis , Ostrowski Michael C. , Leone Gustavo
Published: February 2008

We developed stromal- and epithelial-specific cre-transgenic mice to directly visualize epithelial-mesenchymal transition (EMT) during cancer progression in vivo. Using three different oncogene-driven mouse mammary tumor models and cell-fate mapping strategies, we show in vivo evidence for the existence of EMT in breast cancer and show that myc can specifically elicit this process. Hierarchical cluster analysis of genome-wide loss of heterozygosity reveals that the incidence of EMT in invasive human breast carcinomas is rare, but when it occurs it is associated with the amplification of MYC. These data provide the first direct evidence for EMT in breast cancer and suggest that its development is favored by myc-initiated events. [Cancer Res 2008;68(3):937–45]