bluuebunny/crossref_metadata_2025 huggingface dataset:
On the relation of apparent naturalness to phonetic perceptual identification of vowels
Authors: Wissig Stephanie , Ferro Daria F. , Liberman Kate , Thompson Jill , Remez Robert E.
Published: September 2013

A set of synthetic test syllables was created varying the attributes of naturalness and phonetic vowel height and advancement. These acoustic items were used in tests calibrating the relation of naturalness to phonetic perceptual resolution. Two acoustic methods were used to create naturalness variants: (1) variation in the excitation of the synthetic voicing source and (2) variation in the bandwidth of the formant centers. A naturalness tournament was composed of items drawn from the test series, and the sensitivity of perceivers to the vowel contrast was estimated with the cumulative d′ across the series in identification tests. These outcomes reveal different effects of each acoustic manipulation: an independence of the outcome of the naturalness tournament and the measures of phonetic sensitivity in one case and a close relation between naturalness and phonetic resolution in the other. Together, the findings show that intelligibility and naturalness can be either orthogonal or contingent aspects of speech perception. These measures offer a tool to understand rule-based and exemplar-based components of phonetic perception. [Research supported by NIH (DC00308).]
Gradient sensitivity to acoustic detail and temporal integration of phonetic cues
Authors: McMurray Bob , Clayards Meghan A. , Aslin Richard N. , Tanenhaus Michael K.
Published: September 2013

Speech contains systematic covariation at the subphonemic level that could be used to integrate information over time (McMurray et al., 2003; Gow, 2001). Previous research has established sensitivity to this variation: activation for lexical competitors is sensitive to within-category variation in voice-onset-time (McMurray et al., 2002). This study extends this investigation to other subphonemic speech cues by examining formant transitions (r/l and d/g), formant slope (b/w) and VOT (b/p) in an eye-tracking paradigm similar to McMurray et al. (2002). Vowel length was also varied to examine temporal organization (e.g., VOT precedes the vowel). Subjects heard a token from each continua and selected the target from a screen containing pictures of the target, competitor and unrelated items. Fixations to the competitor increased with distance from the boundary along each of the speech continua. Unlike prior work, there was also an effect on fixations to the target. There was no effect of vowel length on the d/g or r/l continua, but rate dependent continua (b/w and b/p) showed length effects. Importantly, the temporal order of cues was reflected in the pattern of looks to competitors, providing an important window into the processes by which acoustic detail is temporally integrated.
Effects of human fatigue on speech signals
Authors: Stamoulis Catherine
Published: September 2013

Cognitive performance may be significantly affected by fatigue. In the case of critical personnel, such as pilots, monitoring human fatigue is essential to ensure safety and success of a given operation. One of the modalities that may be used for this purpose is speech, which is sensitive to respiratory changes and increased muscle tension of vocal cords, induced by fatigue. Age, gender, vocal tract length, physical and emotional state may significantly alter speech intensity, duration, rhythm, and spectral characteristics. In addition to changes in speech rhythm, fatigue may also affect the quality of speech, such as articulation. In a noisy environment, detecting fatigue-related changes in speech signals, particularly subtle changes at the onset of fatigue, may be difficult. Therefore, in a performance-monitoring system, speech parameters which are significantly affected by fatigue need to be identified and extracted from input signals. For this purpose, a series of experiments was performed under slowly varying cognitive load conditions and at different times of the day. The results of the data analysis are presented here.
HOCUS: The Haskins optically-corrected ultrasound system for measuring speech articulation
Authors: Whalen D. H. , Iskarous Khalil , Tiede Mark K. , Ostry David J.
Published: September 2013

The tongue is the most important supralaryngeal articulator for speech, yet, because it is typically out of view, its movements have been difficult to quantify. Here is described a new combination of techniques involving ultrasound in conjunction with an optoelectric motion measurement system (Optotrak). Combining these, the movements of the tongue are imaged and simultaneously corrected for motion of the head and of the ultrasound transceiver. Optotrak’s infrared-emitting diodes are placed on the transceiver and the speakers head in order to localize the ultrasound image of the tongue relative to the hard palate. The palate can be imaged with ultrasound by having the ultrasound signal penetrate a water bolus held against the palate by the tongue. This trace is coregistered with the head and potentially with the same talker’s sagittal MR image, to provide additional information on the unimaged remainder of the tract. The tongue surface, from the larynx to near the tip, can then be localized in relationship to the hard palate. The result is a fairly complete view of the tongue within the vocal tract at sampling rates appropriate for running speech. A comparison with other imaging vocal tract systems will be presented. [Work supported by NIH Grant DC-02717.]
Vowel length in Farsi
Authors: Shademan Shabnam
Published: September 2013

This study tests whether Farsi vowels are contrastive with respective to length. Farsi has a six-vowel system with three lax vowels and three tense vowels. Both traditional grammarians and modern linguists believe that Farsi tense vowels are longer than lax vowels, and that there are no vowel pairs that contrast only in length. However, it has been suggested that Farsi exhibits compensatory lengthening, which is triggered by the deletion of glottal consonants in coda position in informal speech (Darzi, 1991). As a result, minimal pairs such as [tar] and [tarh] should contrast only with respect to vowel length. A corpus of 90 words of the form CVC, CVCG, CVGC, and CVCC (where V=a vowel and G=a glottal consonant) was recorded, and durations of vowels in different contexts were measured and compared. Preliminary results show that lax vowel durations fall into three groups with CVCC longer than CVCG/CVGC, and the latter longer than CVC. It remains to be seen whether CVCG/CVGC words show compensatory lengthening when the glottal consonant is deleted.
A rapid method for calculating time domain scattering from a penetrable bottom
Authors: Feuillade C.
Published: September 2013

The density contrast surface is an appropriate model for many water–seafloor interfaces, and the formalism of D. Chu [J. Acoust. Soc. Am. 86, 1883–1896 (1989)], for the impulse response of a point source to a density contrast wedge, facilitates the extension of wedge assemblage boundary scattering models to rough penetrable surfaces. Chu’s method, however, is computationally intensive, since it necessitates finding the multiple roots of a characteristic eigenvalue equation, and evaluating a corresponding power series, for each wedge apex. In this work, the direct, reflected, and diffracted field components of a density contrast wedge are considered, and the relationships between them investigated. In particular, the origin and behavior of diffractions associated with specular reflections of the source in the faces of the wedge is studied. Results show how a proper physical understanding of these phenomena leads to a simple modification of the Biot–Tolstoy theory [J. Acoust. Soc. Am. 29, 381–391 (1957)], which then permits rapid calculations of acoustic bottom scattering and penetration in the time domain to be performed for typical sediment structures seen on the seafloor. [Work supported by ONR/NRL.]
Listening to the acoustics in concert halls
Authors: Beranek Leo L. , Griesinger David
Published: September 2013

How does acoustics affect the symphonic music performed in a concert hall? The lecture begins with an illustrated discussion of the architectural features that influence the acoustics. Boston Symphony Hall, which was built in 1900 when only one facet of architectural design was known, now rates as one of the world’s great halls. How this occurred will be presented. Music is composed with some acoustical environment in mind and this varies with time from the Baroque to the Romantic to the Modern musical period. Conductors vary their interpretation according to the hall they are in. Well-traveled listeners and music critics have favorite halls. The lecture then presents a list of 58 halls rank ordered according to their acoustical quality based on interviews of music critics and conductors. Modern acoustical measurements made in these halls are compared with their rankings. Music recordings will be presented that demonstrate how halls sound that have different measured acoustical parameters. Photographs of a number of recently built halls are shown as examples of how these known acoustical factors have been incorporated into architectural design.
Watching bats find food: Do we classify the signals, the strategies, or the bats?
Authors: Simmons James A.
Published: September 2013

The fact that different families, genera, and even species of echolocating bats broadcast characteristic sonar signals has motivated numerous efforts to classify bats according to signal design, which has received support from correlations with both peripheral and central auditory physiology. Signal types vary according to the situations in which bats have been observed hunting for food, so this classification has been extended to the hunting strategies they use. The availability of new technical means for watching and documenting the behavior of echolocating bats in real time (thermal infrared video cameras, night-vision video with infrared illumination, video recorders with ultrasonic audio channels) makes it possible to follow individual bats long enough to observe variations in their behavior over periods of seconds to minutes. These observations reveal that at least some species nominally classified as using just one hunting strategy in fact use several strategies according to prevailing conditions, sometimes using different strategies in the course of only a few minutes. The historic inaccessibility of bats to real-time observation in the dark may have lead to exaggerated stereotyping of their behavior. [Work supported by ONR, NSF.]
Production and perception of Persian geminate stops at three speaking rates
Authors: Hansen Benjamin B.
Published: September 2013

An experiment was designed to determine whether the geminate/singleton category distinction is maintained at fast speaking rates in Persian. Three speakers of Tehrani Persian read test words containing [t,t:,d,d:] in carrier sentences at three speaking rates. The categories do not overlap within a given speaking rate, but the fastest geminates do overlap the normal-rate singletons, implying that the listener must take speaking rate into account in order to perceive the category distinction. The ratio of the consonant closure to the preceding vowel (C/V) is not a useful rate-independent parameter for describing the geminate/singleton boundary in Persian since in Persian the vowel preceding a geminate is slightly longer. However, it was found that the marginal consonant closure (above a minimum closure of about 20 ms) maintains a fixed proportion of the average syllable duration, regardless of rate. This fixed proportion is distinct for geminates and singletons, and so may be used as a single rate-independent parameter for defining the category distinction. Perception tests on natural sentences showed that the distinction is perceptible at each of the three speaking rates. The perceptual response to manipulation of the closure durations indicated that, besides duration, additional cues to the distinction are present.
Microlesions induced by microcavitation during contrast echocardiography
Authors: Miller Douglas , Li Peng , Gordon David , Armstrong William
Published: September 2013

The purpose of this study was to search for histologically identifiable lesions associated with myocardial contrast echocardiography (MCE) in rats. Diagnostic ultrasound scans with 1:4 end-systolic triggering provided a short-axis view of the left ventricle in rats at 1.5 MHz with 1.45-μs pulses of 1.7 Mechanical Index. Two relatively high doses (500 μl/kg) of OptisonTM ultrasound contrast agent were given 5 min apart during 10 min of MCE. One day after scanning, rats were sacrificed and the hearts fixed for histology. Slides were scored blind by a pathologist, and photomicrographs in the anterior half of the heart sections were characterized by digital image analysis. Microlesions identified by inflammatory infiltrates were scattered primarily over the anterior half of the sections. Pathologically, there was inflammatory cell infiltration in areas of 0.6±0.5% of the sections for shams and 3.6±3.6% for MCE (P<0.01). Analysis of the photographs from the anterior wall found microlesion areas of 0.5±0.8% for shams and 7.4±5.0% for MCE (P<0.02). Diagnostic MCE at high Mechanical Index has a potential for causing microscale lesions in the myocardium by nucleation of microcavitation. [Work supported by NIH Grant EB0338.]
The effect of spatial distribution on the annoyance caused by simultaneous sounds
Authors: Vos Joos , Bronkhorst Adelbert W. , Fedtke Thomas
Published: September 2013

A considerable part of the population is exposed to simultaneous and/or successive environmental sounds from different sources. In many cases, these sources are different with respect to their locations also. In a laboratory study, it was investigated whether the annoyance caused by the multiple sounds is affected by the spatial distribution of the sources. There were four independent variables: (1) sound category (stationary or moving), (2) sound type (stationary: lawn-mower, leaf-blower, and chain saw; moving: road traffic, railway, and motorbike), (3) spatial location (left, right, and combinations), and (4) A-weighted sound exposure level (ASEL of single sources equal to 50, 60, or 70 dB). In addition to the individual sounds in isolation, various combinations of two or three different sources within each sound category and sound level were presented for rating. The annoyance was mainly determined by sound level and sound source type. In most cases there were neither significant main effects of spatial distribution nor significant interaction effects between spatial distribution and the other variables. It was concluded that for rating the spatially distrib- uted sounds investigated, the noise dose can simply be determined by a summation of the levels for the left and right channels. [Work supported by CEU.]
Biomedical engineering: A platform for research and innovation in ultrasound
Authors: Holland Christy K.
Published: September 2013

An undergraduate or graduate degree in biomedical engineering prepares students to solve problems at the interface between engineering and medicine. Biomedical engineering encompasses evolving areas such as advanced medical imaging for diagnosis and treatment of disease, tissue engineering for designing and manufacturing biological implants for damaged or diseased tissues and organs, and bioinformatics for determining which genes play a major role in health and disease. Biomedical engineering academic programs produce graduates with the ability to pursue successful careers in the biomedical device industry or to obtain advanced degrees leading to careers in biomedical engineering research, medicine, law or business. Biomedical engineering majors take courses in biology, anatomy, physics, chemistry, engineering, mathematics and medical product design and value life-long learning. Students learn to work effectively in interdisciplinary teams comprised of individuals with diverse social, cultural and technical backgrounds. Biomedical engineering is becoming increasingly important in imaging and image-guided research. Some examples of innovative ultrasound technology under development are ultrasound devices to accelerate the dissolution of blood clots, advanced surgical instruments with ultrasound guidance and ultrasound contrast agents for targeted drug delivery. Biomedical engineering is a great career choice for technically minded individuals who endeavor to work on applied problems that are medically relevant.
Detection of uncertain seismic signals
Authors: Harris D. B.
Published: September 2013

Current practice in seismic event detection is concentrated at the extremes of a spectrum of possibilities determined by the degree of knowledge available about the signals to be detected. At one end of the spectrum, information is available about only the frequency content of the signal. Correspondingly, simple energy detectors operating in fixed passbands are the detection method of choice: the seismological standard for detection of events over broad regions. At the other end of the spectrum, the signal is completely known. For such cases, correlation detectors (matched filters) are indicated. Correlation detectors are the emerging standard for detection of repetitive events from sources with very limited geographic extent (a few wavelengths), e.g., mines, compact earthquake swarms, and aftershock sequences. It is desirable to seek detectors that operate between the extremes, i.e., that have much of the sensitivity of correlation detectors, but more of the flexibility of energy detectors to detect signals with greater uncertainty. Subspace detectors offer one approach to achieving this trade-off. This talk describes an application of subspace detectors to detect events in a swarm with significant signal variability, and demonstrates the theoretical ability of these detectors to grade almost continuously between correlators and energy detectors.
Robert Apfel’s contribution to clinical diagnostic ultrasound: The mechanical index
Authors: Holland Christy K.
Published: September 2013

The mechanical index, MI, resulted from theoretical considerations of the short-pulse acoustic threshold for inertial cavitation in water populated with microbubbles of all sizes [R. E. Apfel and C. K. Holland, Ultrasound Med Biol. 17, 179–185 (1991)]. In this review, the onset of cavitation will be discussed with reference to Robert Apfel’s legacy of theoretical and experimental data. The questions arise: Can the utility of the MI be extended to situations in which the threshold MI is exceeded, thereby allowing for some estimate of the quantification of a potential bioeffect due to microcavitation? Also, can the MI be extended to situations in which pulses are, unlike the original formulation, not short? Is there a theoretical or semi-empirical basis for the MI threshold below which cavitation is unlikely? Can the MI be used to predict gas contrast agent destruction? The possible consequences of gas body activation associated with aerated lung tissue, intestinal gas pockets or encapsulated gas contrast agents represent specific instances of cavitation considerations relevant to clinical practice. Monitoring the real-time display of the MI (mandated by the FDA) helps clinicians evaluate and minimize the potential risks in the use of diagnostic ultrasound instrumentation. [Research supported by National Institutes of Health Grant R29 HL58761.]
Direct measurement of single and multiple passband intelligibilities: Comparison with estimates based upon the Speech Intelligibility Index
Authors: Warren Richard M. , Bashford James A. , Lenz Peter W.
Published: September 2013

The intelligibility of individual bands spanning the speech spectrum is of interest for theoretical and practical reasons, and has been the subject of considerable experimental investigation. Direct measurement of passband intelligibility can be confounded with contributions from filter slopes, but by employing sufficiently high orders of FIR filtering, the present study has removed all slope contributions and measured directly intelligibilities of 1-octave and 1/3-octave passbands. Stimuli employed were based upon the same commercial recording of monosyllabic words and the same frequency bands used for the Speech Intelligibility Index (SII) [American National Standards Institute, S3.5, 1997]. SII employs an indirect procedure for estimating intelligibility: lists of band ‘‘importance’’ values are derived from intelligibility scores for high-pass and low-pass speech having incrementally varied cutoff frequencies. These importance values are correlated with intelligibility, and were transformed into intelligibility estimates using the published transfer function. Directly measured intelligibilities differ for some, but not all, SII-based intelligibility estimates for bands heard singly and in combination. Direct determination of intelligibilities of individual and multiple passbands is suggested as a simple and accurate alternative to the methods based upon SII and other indirect procedures for estimating the intelligibility of frequency-limited speech. [Work supported by NIH.]
Ocean acoustic backscattering: When you can ignore acoustic scatter from turbulence and when you can’t
Authors: Ross Tetjana , Lavery Andone , Lueck Rolf , Wiebe Peter , Lawson Gareth
Published: September 2013

While models predicting measurable levels of acoustic backscattering from oceanic turbulence have been around for decades, they have proven notoriously hard to confirm. This is, in part, because potential turbulent scattering layers often coincide with zooplankton layers. Therefore, as zooplankton are known to cause measurable acoustic scatter, the source of scatter is obscured. Furthermore, estimates of zooplankton abundance from acoustic scattering measurements have been shown to agree with independent measures under a number of circumstances. This gives circumstantial evidence to fuel the belief that scatter from turbulence is negligible. In addition, even if the turbulent scattering theory is correct, it predicts that over most of the ocean the turbulent intensities and/or stratifications are too weak to give turbulent scatter of a similar magnitude as is observed from zooplankton layers. Yet, despite all this, here data are presented that show circumstances when scatter from turbulence is significant. The areas of the ocean (mostly coastal) that one might have to be concerned about turbulent scatter are discussed, as well as the intriguing idea of using technology already developed for zooplankton observation to measure turbulence. This technology could facilitate the in situ study of biophysical interactions between zooplankton and turbulence.
The role of shear and longitudinal waves in the kidney stone comminution by a lithotripter shock pulse
Authors: Sapozhnikov Oleg A. , Cleveland Robin O. , Bailey Michael R.
Published: September 2013

Shock wave lithotripsy has been in clinical use for 20 years but there is no consensus as to the main mechanism of kidney stone comminution. Experiments show that several mechanisms might be involved, including cavitation, spallation, and dynamic fatigue. Until recently, little attention was paid to shear elasticity of the stone material, i.e., mechanical load was mainly attributed to the longitudinal waves. In a previous numerical study, we found that shear elasticity resulted in tremendous change in the stress pattern inside cylindrical stones. The numerical model has been extended to study elastic waves in asymmetric inhomogeneous stones. Strains and stresses in the stone are calculated based on the Lamé equation for an isotropic elastic medium. Lithotripter shock waves of various temporal and spatial profiles were considered according to several clinical models of lithotripters. Maximum compression, tensile and shear stresses are predicted as a function of stone dimension and shape. The model predicts that both shear and longitudinal waves play an important role in creating the regions of excess stresses where cracks can be formed. The results of modeling are compared with the experimental observations. [Work supported by ONRIFO, CRDF, NIH-Fogarty, RFBR, NIH, and Whitaker Foundation.]
The temporal effect in a notched-noise masker for normal-hearing and hearing-impaired listeners
Authors: Strickland Elizabeth A.
Published: September 2013

This is another in a series of studies on the relationship between the temporal effect (or overshoot) and the cochlear active process. The temporal effect refers to the change in threshold for a short-duration tone as it is delayed from the onset of a longer-duration masker. In a previous study, the temporal effect was measured as a function of signal level in a broadband masker, for listeners with normal hearing and listeners with varying degrees of cochlear hearing loss. When analyzed in terms of cochlear input–output functions, the results were consistent with a decrease in gain at the signal frequency during the course of the masker, as well as a decrease in gain with hearing impairment. In the present study, the temporal effect was measured for a 10-ms, high-frequency signal in a masker with a symmetric notch (relative frequency of 0.3) about the signal frequency, for listeners with normal hearing and cochlear hearing loss. This condition is of interest because the thresholds may reflect the effects of suppression as well as excitatory masking. The relationship between the degree of hearing impairment and the growth of masker level with signal level will be analyzed. [Work supported by the Kinley Trust.]
Blind prediction of broadband coherence time at basin-scales
Authors: Spiesberger John L. , Tappert Frederick , Jacobson Andrew R.
Published: September 2013

A blind comparison with data is made with a model for the coherence time of broadband sound (133 Hz, 17 Hz bandwidth) at 3709 km. Coherence time is limited by changes in the ocean because the acoustic instruments are fixed to the Earth on the bottom of the sea with time bases maintained by atomic clocks. Although the modeled coherence time depends a bit on the difficult problem of correctly modeling relative signal-to-noise ratios, normalized correlation coefficients of the broadband signals for the data (model) are 0.90 (0.83), 0.72 (0.59), and 0.51 (0.36) at lags of 2, 4.1, and 6.2 mins respectively. In all these cases, observed coherence times are a bit longer than modeled. The temporal evolution of the model is based on the linear dispersion relation for internal waves. Acoustic propagation is modeled with the parabolic approximation and the sound speed insensitive operator.
Aeroacoustics of [s]
Authors: Howe Michael S. , McGowan Richard S.
Published: September 2013

The theory of the sibilant fricative [s] is formulated and solved as a mathematical problem of aeroacoustics. Air is forced through the constriction between the tongue and the hard palate by the intra-oral pressure, forming a jet that strikes the upper incisors and leaves the mouth through a gap between the upper and lower incisors. The principal source of sound is the diffraction of jet turbulence pressure fluctuations by the incisors. The spectrum of these pressure fluctuations incident on the teeth is modeled analytically using an empirical formula adapted from boundary layer theory. Predictions are made of the far field acoustic pressure spectrum by reference to measured and estimated values of vocal tract dimensions and intra-oral pressure. Predicted spectra compare well with observations. The principal spectral peaks are determined by vocal tract physiology anterior to the tongue–palate constriction. The theory furnishes the first correct predictions of the dependence of the overall sound pressure level on the intra-oral pressure. This presentation will interpret the mathematical model in a nonmathematical manner. [Work supported, in part, by Grant NIDCD-01247 to CReSS LLC.]
Behavioral estimates of compression in normal and impaired ears
Authors: Plack Christopher J. , Oxenham Andrew J.
Published: September 2013

Over the last 7 years, forward masking techniques have been used to estimate peripheral compression in the human auditory system. The growth of masking and temporal masking curve (TMC) techniques estimate the response to a tone at characteristic frequency (CF) by comparing the masking function (masker level as a function of signal level and masker-signal interval, respectively) for a masker at the signal frequency with the masking function for a masker below the signal frequency (assumed to be processed linearly at high CFs). Compression can also be estimated using the additivity of forward masking technique, in which the effects on signal threshold of combining two equally effective maskers are used to derive the exponent. Overall, the results suggest strong compression in humans (exponent of 0.2) across the range of CFs tested so far (250 to 8000 Hz). The behavioral techniques also suggest that a sensorineural hearing loss of greater than about 50 dB results in an almost complete linearization of the response. However, recent TMC data suggest that less severe hearing losses are associated with a reduction in gain, and a reduction in the level range over which compression is present, but no reduction in the maximum compression.
Synergy of ultrasound, elasticity, and optoacoustic imaging for improved detection and differentiation of cancerous tissue
Authors: Emelianov Stanislav , Aglyamov Salavat , Shah Jignesh , Sethuraman Shriram , Scott Guy , Schmitt Rainer , Karpiouk Andrei , Motamedi Massoud , Oraevsky Alexander
Published: September 2013

The effective management of cancer requires early yet reliable detection, localization, and diagnosis. Therefore, there is a definite and urgent clinical need for an imaging technique that is widely available, is simple to perform, is safe, and that can detect and adequately diagnose cancer. In this paper we present a hybrid imaging technology based on fusion of complementary imaging modalities ultrasound, optoacoustics, and elastography to take full advantage of the many synergistic features of these modalities and thus to significantly improve sensitivity and specificity of cancer imaging. To evaluate our approach, numerical and experimental studies were performed using heterogeneous phantoms where ultrasonic, optical, and viscoelastic properties of the materials were chosen to closely mimic soft tissue. The results of this study suggest that combined ultrasound-based imaging is possible and can provide more accurate, reliable and earlier detection and diagnosis of tissue pathology. In addition, monitoring of cancer treatment and guidance of tissue biopsy are possible with combined imaging system. Practical and experimental aspects of combined imaging will be discussed with emphasis on data capture and signal/image processing algorithms. The paper will conclude with a discussion of the advantages, limitations, and potential clinical applications of the combined imaging technique.
A dual-piston ring-driven X-spring transducer
Authors: Butler Alexander L. , Butler John L. , Pendleton Robert L. , Ead Richard M.
Published: September 2013

Tonpilz transducers generally consist of a stack of piezoelectric material sandwiched between a single piston and an inertial tail mass or between two pistons. The result is a transducer with a large length-to-diameter ratio. The X-spring transducer design, based on U.S. Patent 4845688, allows a means for a shorter transducer length through an orthogonal piezoelectric drive system coupled to the pistons by lever arms. We present here a low-frequency, dual-piston piezoelectric ceramic ring driven version with a length of only 10 in. and a diameter of 19 in. Both single-element and two-element array results are presented. The measured response is shown to be in agreement with the finite-element model with a smooth, wideband 300- to 550-Hz response for this dual-piston, ring-driven X-spring transducer. [Work supported by a Phase II SBIR, through NUWC, Newport, RI 02841.]
Characterization and differentiation of three solid tumors using quantitative ultrasound
Authors: Oelze Michael L. , O’Brien William D. , Zachary James F.
Published: September 2013

Three kinds of solid tumors were acquired and scanned in vivo ultrasonically. The first tumor series (fibroadenoma) was acquired from tumors that had spontaneously developed in rats. The second tumor series was acquired by culturing a carcinoma cell line (4T1-MMT) in culture media and injecting the cells into Balb/c mice. The third tumor was acquired by transplanting a soft-tissue sarcoma cell line (EHS) into C57BL mice. The tumors were allowed to grow to 1 cm in size and then scanned ultrasonically. The scatterer properties of average scatterer diameter and acoustic concentration were estimated using a Gaussian form factor from the backscattered ultrasound measured from the tumors. Parametric images of the tumors were constructed utilizing estimated scatterer properties for regions of interest inside the tumors. The parametric images showed distinct differences between the various tumor types. Quantitatively, the tumors could be distinguished through feature analysis plots of average scatterer size versus acoustic concentration. Comparison with photomicrographs of the tumors showed structures similar in size to the ultrasound estimates. [Work supported by NIH Grant F32 CA96419 to MLO and by the University of Illinois Research Board.]
Place specificity measured in forward and interleaved masking in cochlear implants
Authors: Azadpour Mahan , AlJasser Arwa , McKay Colette M.
Published: September 2013

Interleaved masking in cochlear implants is analogous to acoustic simultaneous masking and is relevant to speech processing strategies that interleave pulses on concurrently activated electrodes. In this study, spatial decay of masking as the distance between masker and probe increases was compared between forward and interleaved masking in the same group of cochlear implant users. Spatial masking patterns and the measures of place specificity were similar between forward and interleaved masking. Unlike acoustic hearing where broader tuning curves are obtained in simultaneous masking, the type of masking experiment did not influence the measure of place specificity in cochlear implants.
Graph-theoretic analysis of a model for the coupling between photosynthesis and photorespiration
Authors: Amin Md. Ruhul , Roussel Marc R.
Published: September 2013

We develop and analyze a mathematical model based on a previously enunciated hypothesis regarding the origin of rapid, irregular oscillations observed in photosynthetic variables when a leaf is transferred to a low-CO2atmosphere. This model takes the form of a set of differential equations with two delays. We review graph-theoretical methods of analysis based on the bipartite graph representation of mass-action models, including models with delays. We illustrate the use of these methods by showing that our model is capable of delay-induced oscillations. We present some numerical examples confirming this possibility, including the possibility of complex transient oscillations. We then use the structure of the identified oscillophore, the part of the reaction network responsible for the oscillations, along with our knowledge of the plausible range of values for one of the delays, to rule out this hypothetical mechanism.
FIRST-PRINCIPLES STUDY ON β-SiC/BNNT CORE/SHELL NANOCABLE
Authors: ZOU X. C. , OUYANG J. , WU M. S. , LIU G. , LEI X. L. , OUYANG C. Y. , XU B.
Published: September 2013

In this paper, we studied the structural and electronic properties of core/shell nanocables composed of cubic silicon carbide nanowires (β- SiCNW ) and boron nitride nanotubes (BNNT) using first-principles pseudopotential plane wave method within density functional theory. Our results show that the β- SiC /BNNT heterojunction structures are metallic, which primarily originates from the contributions of the BNNTs and the surfaces of SiCNW s. The BNNTs exhibit metallic characters after the SiC nanowires are inserted. The transition of the BNNTs is attributed to the charge transfer between BNNTs and SiCNW s.
INTEGRATION OF KEYPOINTS AND EDGES FOR IMAGE RETRIEVAL
Authors: CHEN LIANG-HUA , HUNG YAO-LING , SU CHIH-WEN
Published: September 2013

The usefulness of an image database depends on whether the image of interest can be easily located. Feature extraction is a crucial step of image retrieval. The well-known SIFT descriptor is a keypoint-based image feature. It can be used to robustly find the same objects in different images, i.e. achieve the object recognition task. However, it is not effective on the image retrieval task, i.e. finding images with similar content. To improve the SIFT algorithm, we propose a robust image retrieval algorithm based on the integration of keypoints and edges information. Our approach is robust to translation, rotation and partial occlusion of the object. Experimental results indicate that the proposed algorithm is effective and outperforms the SIFT algorithm.
Crystallization Analysis and Control of Ammonia-Based Air Source Absorption Heat Pump in Cold Regions
Authors: Wu Wei , Wang Baolong , Shi Wenxing , Li Xianting
Published: September 2013

Energy consumption of heating and domestic hot water is very high and will keep increasing. Air source absorption heat pump (ASAHP) was proposed to overcome the problems of low energy efficiency and high air pollution existing in boiler systems, as well as the problem of bad performance under low ambient temperatures for electrical heat pumps. In order to investigate the crystallization possibility of ammonia-salt ASAHP, crystallization margin (evaluated by solution mass concentration) at generating temperature ranging from 100 to 150°C, evaporating temperature from −30 to 10°C, and condensing temperature from 30 to 65°C are analyzed. To prevent the NH3–NaSCN solution from crystallizing, ASAHP integrated with pressure booster located between the evaporator and absorber is simulated. Analysis and comparisons show that NH3–NaSCN is easy to crystallize at relatively high generating temperature, low evaporating temperature, and low condensing temperature. But crystallization margin of NH3–LiNO3 can always stay above 5% for most conditions, keeping away from crystallization. Pressure booster can effectively avoid the crystallization problem that will take place in the NH3–NaSCN ASAHP system.
Respiratory Management in the Patient with Spinal Cord Injury
Authors: Galeiras Vázquez Rita , Rascado Sedes Pedro , Mourelo Fariña Mónica , Montoto Marqués Antonio , Ferreiro Velasco M. Elena
Published: September 2013

Spinal cord injuries (SCIs) often lead to impairment of the respiratory system and, consequently, restrictive respiratory changes. Paresis or paralysis of the respiratory muscles can lead to respiratory insufficiency, which is dependent on the level and completeness of the injury. Respiratory complications include hypoventilation, a reduction in surfactant production, mucus plugging, atelectasis, and pneumonia. Vital capacity (VC) is an indicator of overall pulmonary function; patients with severely impaired VC may require assisted ventilation. It is best to proceed with intubation under controlled circumstances rather than waiting until the condition becomes an emergency. Mechanical ventilation can adversely affect the structure and function of the diaphragm. Early tracheostomy following short orotracheal intubation is probably beneficial in selected patients. Weaning should start as soon as possible, and the best modality is progressive ventilator-free breathing (PVFB). Appropriate candidates can sometimes be freed from mechanical ventilation by electrical stimulation. Respiratory muscle training regimens may improve patients’ inspiratory function following a SCI.
“Quo Vadis” Oncologic Hyperthermia?
Authors: Szasz Andras
Published: September 2013

Hyperthermia was the very first oncotherapy in human medicine based directly on sacral and philosophical roots in ancient cultures. The discovery of electromagnetism gave new hopes a century ago; however, up to now it has been suffering from lack of wide applications. Oncological hyperthermia struggles with multiple technical and medical problems which are far from the complete solution. Technically, the deep heating, the precise focusing, the technical control, and repeatability are challenging. The missing medical explanation of the phenomenon, together with the he missing measurable dose hinders the acceptance of hyperthermia. The contra-feedback of physiology mechanisms makes this method hardly controllable. Multiple, most promising results and studies are mixed together with some negatives and controversial consequences, causing huge fluctuations of its applications. There are positive and negative “believers” of the method, but the decisional facts are missing. A new way gives shape to the development: heating in nanorange, which could solve most of the open problems in oncological hyperthermia.
Synthesis, Characterisation, andIn VitroAnticancer Activity of Curcumin Analogues Bearing Pyrazole/Pyrimidine Ring Targeting EGFR Tyrosine Kinase
Authors: Ahsan Mohamed Jawed , Khalilullah Habibullah , Yasmin Sabina , Jadav Surender Singh , Govindasamy Jeyabalan
Published: September 2013

In search of potential therapeutics for cancer, we described herein the synthesis, characterization, andin vitroanticancer activity of a novel series of curcumin analogues. The anticancer effects were evaluated on a panel of 60 cell lines, according to the National Cancer Institute (NCI) screening protocol. There were 10 tested compounds among 14 synthesized compounds, which showed potent anticancer activity in both one-dose and 5-dose assays. The most active compound of the series was 3,5-bis(4-hydroxy-3-methylstyryl)-1H-pyrazole-1-yl(phenyl)methanone (10) which showed mean growth percent of −28.71 in one-dose assay and GI50values between 0.0079 and 1.86 µM in 5-dose assay.
What Is the Role of Apelin regarding Cardiovascular Risk and Progression of Renal Disease in Type 2 Diabetic Patients with Diabetic Nephropathy?
Authors: Silva Ana Paula , Fragoso André , Silva Claudia , Viegas Carla , Tavares Nelson , Guilherme Patrícia , Santos Nélio , Rato Fátima , Camacho Ana , Cavaco Cidália , Pereira Victor , Faísca Marilia , Ataíde João , Jesus Ilídio , Neves Pedro
Published: September 2013

Aims. To evaluate the association of different apelin levels with cardiovascular mortality, hospitalization, renal function, and cardiovascular risk factors in type 2 diabetic patients with mild to moderate CKD.Methods. An observational, prospective study involving 150 patients divided into groups according to baseline apelin levels:1≤98 pg/mL, 2 = 98–328 pg/mL, and3≥329 pg/mL. Baseline characteristics were analyzed and compared. Multivariate Cox regression was used to find out predictors of cardiovascular mortality, and multivariate logistic regression was used to find out predictors of hospitalization and disease progression. Simple linear regressions and Pearson correlations were used to investigate correlations between apelin and renal disease and cardiovascular risk factors.Results. Patients’ survival at 83 months in groups 1, 2, and 3 was 39%, 40%, and 71.2%, respectively (P=0.046). Apelin, age, and eGFR were independent predictors of mortality, and apelin, creatinine, eGFR, resistin, and visfatin were independent predictors of hospitalization. Apelin levels were negatively correlated with cardiovascular risk factors and positively correlated with eGFR. Patients with lower apelin levels were more likely to start a depurative technique.Conclusions. Apelin levels might have a significant clinical use as a marker/predictor of cardiovascular mortality and hospitalization or even as a therapeutic agent for CKD patients with cardiovascular disease.
The Effect of CYP2B6, CYP2D6, and CYP3A4 Alleles on Methadone Binding: A Molecular Docking Study
Authors: Kamal Nik Nur Syazana Bt Nik Mohamed , Lim Theam Soon , Tye Gee Jun , Ismail Rusli , Choong Yee Siew
Published: September 2013

Current methadone maintenance therapy (MMT) is yet to ensure 100% successful treatment as the optimum dosage has yet to be determined. Overdose leads to death while lower dose causes the opioid withdrawal effect. Single‐nucleotide polymorphisms (SNP) in cytochrome P450s (CYPs), the methadone metabolizers, have been showen to be the main factor for the interindividual variability of methadone clinical effects. In this study, we investigated the effect of SNPs in three major methadone metabolizers (CYP2B6, CYP2D6, and CYP3A4) on methadone binding affinity. Results showed that CYP2B6*11, CYP2B6*12, CYP2B6*18, and CYP3A4*12 have significantly higher binding affinity to R‐methadone compared to wild type. S‐methadone has higher binding affinity in CYP3A4*3, CYP3A4*11, and CYP3A4*12 compared to wild type. R‐methadone was shown to be the active form of methadone; thus individuals with CYP alleles that binds better to R‐methadone will have higher methadone metabolism rate. Therefore, a higher dosage of methadone is necessary to obtain the opiate effect compared to a normal individual and vice versa. These results provide an initial prediction on methadone metabolism rate for individuals with mutant type CYP which enables prescription of optimum methadone dosage for individuals with CYP alleles.
Quasi-Linear Convection-Dominated Transport Problem Based on Characteristics-Mixed Finite Element Method
Authors: Zhao Peixin , Man Hongying
Published: September 2013

We propose the characteristics-mixed method for approximating the solution to a convection-dominated transport problem. The new method is a combination of characteristic approximation to handle the convection part in time and a mixed finite element spatial approximation to deal with the diffusion part. Boundary conditions are incorporated in a natural fashion. The scheme is locally conservative since fluid is transported along the approximate characteristics on the discrete level and the test function can be piecewise constant. Analysis shows that the scheme has much smaller time-truncation errors than those of standard methods.
Identification of Protein Pupylation Sites Using Bi-Profile Bayes Feature Extraction and Ensemble Learning
Authors: Zhao Xiaowei , Zhang Jian , Ning Qiao , Sun Pingping , Ma Zhiqiang , Yin Minghao
Published: September 2013

Pupylation, one of the most important posttranslational modifications of proteins, typically takes place when prokaryotic ubiquitin-like protein (Pup) is attached to specific lysine residues on a target protein. Identification of pupylation substrates and their corresponding sites will facilitate the understanding of the molecular mechanism of pupylation. Comparing with the labor-intensive and time-consuming experiment approaches, computational prediction of pupylation sites is much desirable for their convenience and fast speed. In this study, a new bioinformatics tool named EnsemblePup was developed that used an ensemble of support vector machine classifiers to predict pupylation sites. The highlight of EnsemblePup was to utilize the Bi-profile Bayes feature extraction as the encoding scheme. The performance of EnsemblePup was measured with a sensitivity of 79.49%, a specificity of 82.35%, an accuracy of 85.43%, and a Matthews correlation coefficient of 0.617 using the 5-fold cross validation on the training dataset. When compared with other existing methods on a benchmark dataset, the EnsemblePup provided better predictive performance, with a sensitivity of 80.00%, a specificity of 83.33%, an accuracy of 82.00%, and a Matthews correlation coefficient of 0.629. The experimental results suggested that EnsemblePup presented here might be useful to identify and annotate potential pupylation sites in proteins of interest. A web server for predicting pupylation sites was developed.