bluuebunny/crossref_metadata_2025 huggingface dataset:
Severe posterior reversible encephalopathy syndrome resolved with craniectomy
Authors: Nagaoka Yoshinobu , Ishikura Kenji , Hamada Riku , Miyagawa Tadashi , Kono Tatsuo , Sakai Tomoyuki , Hamasaki Yuko , Hataya Hiroshi , Honda Masataka
Published: October 2013

Posterior reversible encephalopathy syndrome (PRES) has been thought to be a benign disease, but recently severe cases have been reported with increasing recognition. A 3‐year‐old girl with congenital nephrotic syndrome had rapidly progressed to coma. Computed tomography (CT) of the head showed striking swelling of the brainstem and transtentorial herniation. Emergency decompressive craniectomy was performed. Consecutively, blood pressure was optimally controlled. The patient gradually recovered to the previous state before onset of PRES. Rapid improvement of clinical symptoms and rapid resolution of abnormal findings on serial CT led to diagnosis of PRES. In severe PRES with unstable vital signs, surgical intervention should be considered as well as appropriate blood pressure management.
Neonatal urethral polyps associated with Beckwith–Wiedemann syndrome
Authors: Anzai Yuko , Koshida Shigeki , Yanagi Takahide , Johnin Kazuyoshi , Takeuchi Yoshihiro
Published: October 2013

We report the first case of Beckwith–Wiedemann syndrome without urinary obstruction, but with a congenital urethral polyp as a tumor protruding from the external urinary meatus. The present case suggests a possible relation between Beckwith–Wiedemann and the onset of fibroepithelial polyps in the reno‐urinary system during the neonatal period.
Decreased portal vein flow during Kawasaki disease in a liver transplant patient
Authors: Wakiya Taiichi , Urahashi Taizen , Ihara Yoshiyuki , Sanada Yukihiro , Yamada Naoya , Okada Noriki , Hakamada Kenichi , Mizuta Koichi
Published: October 2013

Abnormalities of liver function tests are frequently documented in patients with Kawasaki disease, but the mechanism responsible for this has not yet been established. Described herein is the case of a 1‐year‐10‐month‐old girl who underwent liver transplantation at 11 months of age. Eleven months after transplantation the patient was diagnosed with Kawasaki disease, which was associated with some portal flow reduction, and received i.v. immunoglobulin, after which fever abated with improvement of portal flow to its pre‐fever level. Abnormalities of liver function tests in Kawasaki disease patients may occur as a result of inflammation of both the biliary and portal systems. There are no reports on the potential relationship between Kawasaki disease and the portal vein, and accumulation of further data is necessary to better examine this relationship.
Frostbite of the liver: An unrecognized cause of primary non‐function?
Authors: Potanos Kristina , Kim Heung Bae
Published: October 2013

Appropriate hypothermic packaging techniques are an essential part of organ procurement. We present a case in which deviation from standard packaging practice may have caused sub‐zero storage temperatures during transport, resulting in a clinical picture resembling PNF. An 18‐month‐old male with alpha‐1‐antitrypsin deficiency underwent liver transplant from a size‐matched pediatric donor. Upon arrival at the recipient hospital, ice crystals were noted in the UW solution. The transplant proceeded uneventfully with short ischemia times. Surprisingly, transaminases, INR, and total bilirubin were markedly elevated in the postoperative period but returned to near normal by discharge. Follow‐up of over five yr has demonstrated normal liver function. Upon review, it was discovered that organ packaging during recovery included storage in the first bag with only 400 mL of UW solution, and pure ice in the second bag instead of slush. This suggests that the postoperative delayed graft function was related to sub‐zero storage of the graft during transport. This is the first report of sub‐zero cold injury, or frostbite, following inappropriate packaging of an otherwise healthy donor liver. The clinical picture closely resembled PNF, perhaps implicating this mechanism in other unexpected cases of graft non‐function.
The Wished‐For Always Wins Until the Winner Was Inevitable All Along: Motivated Reasoning and Belief Bias Regulate Emotion During Elections
Authors: Thibodeau Paul , Peebles Matthew M. , Grodner Daniel J. , Durgin Frank H.
Published: October 2013

How do biases affect political information processing? A variant of the Wason selection task, which tests for confirmation bias, was used to characterize how the dynamics of the recent U.S. presidential election affected how people reasoned about political information. Participants were asked to evaluate pundit‐style conditional claims like “The incumbent always wins in a year when unemployment drops” either immediately before or immediately after the 2012 presidential election. A three‐way interaction between ideology, predicted winner (whether the proposition predicted that Obama or Romney would win), and the time of test indicated complex effects of bias on reasoning. Before the election, there was partial evidence of motivated reasoning—liberals performed especially well at looking for falsifying information when the pundit's claim predicted Romney would win. After the election, once the outcome was known, there was evidence of a belief bias—people sought to falsify claims that were inconsistent with the real‐world outcome rather than their ideology. These results suggest that people seek to implicitly regulate emotion when reasoning about political predictions. Before elections, people like to think their preferred candidate will win. After elections, people like to think the winner was inevitable all along.
Influence of Substituting Dietary Soybean for Air‐Classified Sunflower (Helianthus annuus L.) Meal on Egg Production and Steroid Hormones in Early‐Phase Laying Hens
Authors: Laudadio V , Ceci E , Nahashon SN , Introna M , Lastella NMB , Tufarelli V
Published: October 2013

Contents

Soybean meal (SBM) is the most widely and expensive protein source used in the formulation of poultry diets; however, when the price of SBM increases, poultry nutritionists seek alternative sources that are more economical in formulating least‐cost rations. This research aimed to evaluate the effects of dietary air‐classified sunflower meal (SFM) on some productive parameters and plasma steroid hormones in laying hens. In this trial, 20‐week‐old laying hens (ISA Brown strain) in the early phase of production were randomly assigned to two groups and fed wheat middlings‐based diets containing soybean (135 g/kg; 48% CP) or air‐classified SFM (160 g/kg; 41% CP) as the main protein source. Laying performance, egg size and feed conversion ratio were evaluated for 10 week. Plasma steroid hormones (progesterone and oestradiol) in the hens were quantified weekly. Substituting SBM with air‐classified SFM did not change (p > 0.05) the hens' growth performance, whereas feed consumption and efficiency were positively influenced (p < 0.05) by SFM treatment. Egg production rate was improved in hens fed the SFM diet (p < 0.05), as well as the percentage of medium‐size eggs that was higher for SFM treatment (p < 0.05). Steroid hormones levels were affected by dietary treatment (p < 0.01). From our findings, it could be effective to include air‐classified SFM in early‐phase laying hen diets as an alternative protein source substituting SBM, without negative influence on productive performance and egg traits, reducing also the production costs.
Identification of the novel HLA‐A*24:233 allele in a Chinese individual
Authors: Feng Z.‐H. , Chi X.‐Y. , Hu B. , Jiao S.‐X. , Wang M.‐M.
Published: October 2013

The novel allele A*24:233 was identified in a Chinese individual by sequence‐based typing.
Association of BK viremia with human leukocyte antigen mismatches and acute rejection, but not with type of calcineurin inhibitor
Authors: Hässig A. , Roos M. , Etter A. , Bossart W. , Müller N. , Schiesser M. , Wüthrich R.P. , Fehr T.
Published: October 2013

Introduction

BK viremia and polyomavirus‐associated nephropathy (PVN) represent a significant problem after kidney transplantation. Both are associated with intensified immunosuppression, but other risk factors and the impact of a screening program on outcome are incompletely understood.

Methods

Here, we report on the short‐ and long‐term outcome of a cohort of patients, who were transplanted in 2006/2007 and included in a newly introduced systematic 3‐monthly screening for BK viremia at the University Hospital Zurich. In patients testing positive for BK viremia, screening frequency was intensified and immunosuppression reduced. Patients with suspected PVN underwent transplant biopsy.

Results

Among 152 included patients, 49 (32%) tested positive for BK viremia, but only 8 developed biopsy‐proven PVN. BK viremia had a significant impact on estimated glomerular filtration rate and proteinuria in the first 2 years. Acute rejection episodes and the number of human leukocyte antigen (HLA) mismatches were the strongest independent predictors of BK viremia in a multiple logistic model. In contrast, no particular immunosuppressive agent or regimen was associated with enhanced risk.

Conclusion

Taken together, systematic BK viremia screening led to detection of a high percentage of viremic patients. With adjustment of immunosuppression, an excellent outcome was achieved. The independent association of HLA mismatches with BK viremia suggests impaired polyomavirus immunosurveillance in highly mismatched allografts.
Persistent parvovirus B19 infection resulting in red cell aplasia after allogeneic hematopoietic stem cell transplantation
Authors: Koda Y. , Mori T. , Kato J. , Kohashi S. , Kikuchi T. , Mitsuhashi T. , Murata M. , Uemura T. , Handa M. , Okamoto S.
Published: October 2013

Persistent parvovirus B19 (PVB) infection has been reported sporadically in immunocompromised patients including hematopoietic stem cell and solid organ transplant recipients. However, the pathogenesis of persistent infection has yet to be fully elucidated. We report here a patient with multiple myeloma developing red cell aplasia during the hematopoietic recovery after allogeneic hematopoietic stem cell transplantation (HSCT) caused by PVB. The patient had already had PVB viremia before transplantation and remained asymptomatic. The route of PVB transmission was considered to be direct contact with the patient's family member with primary PVB infection 1 month before transplantation. Treatment with intravenous immunoglobulin resulted in prompt resolution of anemia. These findings suggest that monitoring of PVB DNA is recommended for patients undergoing HSCT and having contact with individuals with documented PVB infection, even if they are asymptomatic.
Glucose‐6‐phosphate dehydrogenase deficiency in Italian blood donors: prevalence and molecular defect characterization
Authors: Maffi D. , Pasquino M. T. , Mandarino L. , Tortora P. , Girelli G. , Meo D. , Grazzini G. , Caprari P.
Published: October 2013

Background

In the countries with high G6PD deficiency prevalence, blood donors are not routinely screened for this genetic defect. G6PD deficiency is often asymptomatic, blood donors may be carriers of the deficiency without being aware of it. The aim of the study was to evaluate the prevalence of G6PD deficiency among the Italian blood donors.

Design and Methods

From October 2009 to April 2011, 3004 blood donors from a large hospital transfusion centre were screened for G6PD deficiency using differential pH‐metry and the characterization of G6PD mutations was performed on G6PD‐deficient subjects. The haematological features of G6PD‐deficient and normal donors were also compared.

Results

Thirty‐three subjects (25 men and 8 women) with low G6PD activity were identified, corresponding to 1·1% of the examined blood donor population. The frequencies of class II severe alleles (Mediterranean, Valladolid, Chatham and Cassano) and class III mild alleles (Seattle, A‐ and Neapolis) were 48% and 43%, respectively. The haematological parameters of G6PD‐ donors were within normal range; however, the comparison between normal and G6PD‐ class II donors showed significant differences.

Conclusion

In Italy, the presence of blood donors with G6PD deficiency is not a rare event and the class II severe variants are frequent. The identification of G6PD‐deficient donors and the characterization of the molecular variants would prevent the use of G6PD‐deficient RBC units when the haemolytic complications could be relevant especially for high risk patients as premature infants and neonates and patients with sickle cell disease submitted to multiple transfusions.
Dynamics and fragmentation of encapsulated gas bubbles
Authors: Allen John S. , May Donovan J. , Ferrara Katherine W.
Published: October 2013

The development of ultrasound contrast agents has fostered an interest in the theoretical dynamics of encapsulated gas bubbles. Originally, micron-sized agents were constructed for diagnostic imaging purposes with a thin shell (<15 nm) of lipid, protein, or polymeric materials. New therapeutic applications for localized drug delivery have led to an interest and development of micron-size bubbles with a thick fluid shell (∼500 nm). Previously some experimental acoustic levitation studies have investigated the capillary wave development on millimeter-size liquid shells. The nonlinear oscillations and fragmentation have not been extensively investigated from the theoretical standpoints. A generalized Rayleigh–Plesset equation has been developed that includes the effects of a thick viscous fluid shell. The equation is compared with other theoretical encapsulated bubble formulations and some recent experimental observations. For a 4.0 μ bubble, with a 500 nm shell of viscosity of 28 cP, insonified over 5 cycles, a maximum relative expansion of 2.2 times the equilibrium radius is predicted at 2.25 MHz and 3.1 times at 1.5 MHz. Predictions from this model regarding the scaling of radial expansion with changes in pressure and frequency have been validated with experimental data.
Time-Reversal signal processing: An overview
Authors: Candy James V.
Published: October 2013

The development of time reversal (T/R) techniques both theoretically and pragmatically has heightened in interest over the last decade. Although the majority of the effort has been concentrated in analysis and proof-in-principle experiments, the evolution of these results have led to potential applications in signal processing. These range from the detection of flaws in nondestructive evaluation (NDE) and scatterers in ocean acoustics to the destruction of kidney stones in biomedical ultrasound. When the medium under investigation has quasihomogenous properties, imaging using the T/R operator has evolved as a viable entity. In this paper we present an overview of T/R from a signal processing perspective. Here we concentrate on the ability of the T/R to perform its primary function of ‘‘focusing’’ on the strongest scatterer. We show how the T/R properties provides us with the optimal spatio-temporal matched-filter property which is utilized in a wide variety of applications, especially in NDE, biomedical, and the newly investigated communications area. We note the relationship of T/R to the inverse solution providing an alternative in deconvolution-type problems.
Analysis of the effects of numerical dispersion on pulses in finite-difference and pseudospectral time-domain methods
Authors: Elston Gareth R. , Bell Judith M. , Capus Chris G.
Published: October 2013

Finite difference (FD) and pseudospectral (PS) time-domain methods are increasingly used for underwater acoustics modeling. Numerical dispersion is unavoidable but can be reduced with an appropriate choice of temporal and spatial discretization (Δt and Δx). As pulses propagate, numerical dispersion causes time-dilation which increases with simulation time and pulse bandwidth. Analysis of the dispersion relation leads to an equation which shows that the time-dilation in a large FD model can be significant for well defined pulses of 50 points per wavelength (PPW). Reducing the dispersion requires a higher grid density. For a 2D model, the memory requirement and time costs vary as the inverse square and inverse cube of Δx. This is contrasted with the PS model in which the time-dilation can be set arbitrarily small for any choice of Δx by reducing Δt. For a fixed spatial grid density, e.g., 10 PPW, the computational cost is linear in the temporal grid density. A locally optimized short-time fractional Fourier transform shows that numerical dispersion has a dramatic effect on the time-frequency characteristics of dispersed pulses, e.g., an input CW pulse becomes a nonlinear upward chirp. These effects are illustrated for a variety of pulses.
Performance metrics for underwater communications: An initial assessment
Authors: Richman Michael S. , Thammakhoune Ned B. , Whitney Scott L. , Edelson Geoffrey S.
Published: October 2013

The relationship between the performance of an underwater acoustic data communications system and operating conditions is investigated. There has been much work devoted toward this end focused on developing mathematical models of the underwater acoustic channel. However, the underwater acoustic environment is a complicated one, and current models do not fully account for the challenging, time-varying conditions. The analysis here is based on actual data transmissions collected during several at-sea tests involving a variety of operating conditions. Metrics have been developed that attempt to characterize properties relating to signal-to-noise ratio, Doppler, multipath spread, channel coherence, and channel complexity. By applying these metrics to data transmissions in conditions with different water depths, carrier frequencies, and source/receiver geometries, a better understanding can be developed of the factors that determine the performance of an underwater communications system. The ultimate goal of this work is to provide a systematic prediction method by computing those metrics that are the true arbiters of performance. This work will also aid in the development and validation of mathematical models of the underwater acoustic environment by providing practical measures with which to compare the simulated channels.
Treatment of ocean bottoms with a layered bottom with some layers having a lower impedance than some overlying layers
Authors: Werby M. F.
Published: October 2013

Some oceans appear to have layers that are less dense and have slower speeds than overlying layers. Perhaps this is due to a gaseous admixture with some of the sediment. This presents some interesting effects in model calculations which are dependent on frequency, layer thickness, and adjacent layers. The mathematical consequence of this is examined.
Subjective and objective evaluations for solo and chamber music performances
Authors: Chiang Weihwa , Wang Weichun
Published: October 2013

Stage acoustics were evaluated in six halls regarding solos (piano, harp, and violin) and chamber music (piano sonata, piano trio, and brass quintet). In each hall professional musicians were seated at two locations: with and without detached side reflectors. The performers expressed their opinions about hearing oneself, hearing others, ease of ensemble, and overall impression. Subjects in the audience were asked about the strength of individual parts and overall impression. A factor analysis yielded four groups among the musicians. Regarding overall impression string players favored the environments with side reflectors. An early-to-direct energy ratio (ED100) was more important than early support (STearly) and late support (STlate) subjectively. The optimum value of ED100 was V11 dB. The overall impression evaluated by the musicians was poorly correlated with the balance of individual parts evaluated by the audiences, indicating that there were orthogonal factors for designing the stage for solo and chamber music performances. [Work supported by the National Science Council of Taiwan.]
The assessment of room acoustics parameters using the MLS technique and numerical simulation
Authors: Gerges Samir N. Y. , Gomes Marcio H. A.
Published: October 2013

Advances in psychoacoustics through the years, have made it possible to evaluate the acoustical quality of a room, based on several numerical parameters that have been developed. Even though there is not a total agreement about which parameters are truly important, some of them are accepted by most of the acousticians. When designing a concert hall, ray-tracing software can be used to calculate some of these parameters. However, some input data carry some uncertainties. Available data for absorption coefficients have to be used carefully and, beyond that, there is not a standardized recommendation for measuring diffusion coefficients, nor a data base for this parameter. This paper presents a comparison of a room simulated with one of the commercial software available (RAYNOISE), and the measured parameters in this same room, using maximum length sequence (MLS). Discrepancies over the results are investigated and analyzed.
Music Technology Program at McGill University
Authors: Depalle Philippe
Published: October 2013

The Music Technology program at McGill University encourages interaction between musical creation, technology, and research. It inherits from a long tradition of music and science combination, which was initiated in the early 1960s at Istvan Anhalt’s instigation and thanks to Hugh Le Caine’s contributions. The pedagogical goal of the program is to provide music students with an environment for professional-level music training and with an intensive focus on programming of advanced music technologies. The undergraduate level has been recently overhauled to reflect the current state of the field and the growing importance of multimedia. This led to a substantial increase of the number of students which will boost next year the population at the graduate level. This factor, in conjunction with the doubling of the academic staff and the creation of a new research center called Centre for Interdisciplinary Research in Music, Media, and Technology (CIRMMT) will reinforce the research activity in the field. CIRMMT also combines several research efforts, which were previously distributed around McGill University (in psychoacoustics, acoustics, cognitive sciences, and electrical engineering applied to music) into a creative interdisciplinary entity that will be housed within the new Faculty of Music Building.
The use of acoustic resonance in particle manipulation and separation
Authors: Brooks Todd L. , Apfel Robert E.
Published: October 2013

Particles in an acoustic standing wave experience a force directed towards pressure nodes or antinodes depending upon particle and host fluid properties. The observation of cork dust banding in air was first reported in 1866 by Kundt, but only recently has there been a renewed interest in utilizing such acoustic forces as a means for practical separation processes in liquids. Applications in biotechnology include two-phase partitioning, agglutination, electro-acoustic cell fusion, and cell retention systems. This talk describes a continuous flow stream with a perpendicularly oriented standing wave in a half or quarter wavelength resonator. This allows a continuous separation process in which the output flow can be split into several streams of different particle concentration, type, or size. Since the acoustic force depends on a particle’s compressibility (as well as size and density contrast), there exists a unique opportunity to separate particles based on this property, not currently available in other separation methods. Competing effects, such as thermal convection, acoustic cavitation, and streaming, reduce separation efficiency, and these must be understood and controlled. A survey of applications will be presented along with recent experimental work and numerical simulations done in the Yale Acoustics Laboratory. [Work supported by NASA through Grant No. NAG8-1351.]
Acoustic resonance determination of the rigidity modulus
Authors: Foote Kenneth G.
Published: October 2013

Acoustic resonance methods are acknowledged to be particularly powerful in the determination of elastic properties of materials. Three measurement techniques for determining the rigidity modulus are described. These involve comparison of the echo spectrum, energy, or waveform with the respective theoretically computed quantity, where the rigidity modulus, or shear-wave sound speed, is a free parameter. The value of this parameter is adjusted to achieve the best fit with measurement. The second technique is illustrated to specify the rigidity modulus of electrical-grade copper. An echo sounder operating at 120 kHz, calibrated by reference to the echo from a 30.05-mm-diam copper sphere, is used to excite a resonance in a 60.07-mm-diam sphere of the same material. The rigidity modulus is found to be 46.86±0.06 GPa and shear-wave sound speed, 2288±2 m/s.
The formation of energy pass bands from periodically spaced point masses on a ribbed cylindrical shell
Authors: Marcus Martin H. , Houston Brian H.
Published: October 2013

An infinite cylindrical shell has bending energy that is able to propagate down the shell at all frequencies with little attenuation other than from material damping and the surrounding medium. In contrast, making the shell finite causes bending resonances to occur only at discrete frequencies. The addition of periodically spaced circumferential stiffeners causes the bending wave dispersion curves to be seen at additional axial modes, which is referred to as Brillouin folding. The stiffeners also cause energy stop bands to occur when the load is a single Fourier mode. In this presentation, periodically spaced point masses in the circumferential direction are added to a ribbed finite cylindrical shell and analyzed via the finite element method. It is seen that Brillouin folding occurs circumferentially. Also, energy pass bands are created in a certain pattern. Analysis of the axisymmetric version of this shell combined with information on the type of aperiodicity yields a prediction of the energy pass band behavior. This provides a qualitative approach toward understanding the motion of nonaxisymmetric shell structures. [Work supported by ONR.]
Vibrations models for offshore structures reinforcing beams
Authors: Sardá Alexandre , Lenzi Arcanjo , Cuschieri Joseph
Published: October 2013

Offshore structures used in oil prospection and production are mainly made of plates reinforced by beams. Vibrations produced by machines and equipment attached to their main structure propagate through such structural components generating usually high-noise levels at the accommodation areas. Power flow analyses through beam reinforced plates require proper models for L and T beams, in order to take into account the influences of their own modes formed in the web and flanges. This work presents a model for vibrations of a typical reinforced beam, made of 2 (or 3) plates welded in L (or T) shape, representing web and flange. Flexural and in-plane shear waves are considered in the plates. Results are compared to finite elements results indicating very good agreement and significantly reduced computational costs.
Time-reversal in a waveguide
Authors: Roux Philippe , Fink Mathias
Published: October 2013

Experimental evidence of time-reversal has been performed at an ultrasonic scale (1.5–3.5 MHz) in a 70 long cm, 1 cm deep waveguide. This laboratory experiment allow us to get rid of noise or ocean fluctuations classically observed. Spatial and temporal time-focusing are studied and interpreted by the method of images in a waveguide or matched-field theory. For a wide band source array, an algorithm based on time-reversal is presented to achieve depth and range shifting without any knowledge of the waveguide properties.
Application of time reversal to underwater acoustic communications
Authors: Edelmann Geoffrey
Published: October 2013

Underwater acoustic communication systems must mitigate the intersymbol interference caused by the time-varying multipath dispersion. Time-reversal (TR), or phase-conjugation, focuses energy back to its origin despite the complexity of the propagation channel. The TR properties of dispersion reduction and the mitigation of the effects of channel fading make time-reversal a potentially attractive component of a coherent communications system. An overview of TR ocean acoustics concepts illustrated with data is presented as related to underwater acoustic communications. Experimental results of TR and control transmissions of binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) communication sequences are also presented together with measured bit error rates. These results will be discussed in relation to environmental fluctuations and their effects on the time-reversal focus. Extended duration (tens of minutes) time-reversal pulse transmissions will be examined as well as the time-evolving characteristics of the channel impulse response. [Work supported by ONR.]
Long distance time reversal and imaging in random media: Numerical simulations
Authors: Blomgren Peter , Papanicolaou George , Zhao Hongkai
Published: October 2013

We have conducted a careful time reversal and imaging study for long distance wave propagation in random media in the underwater acoustics regime. In this talk we briefly describe the computational technology, which is based on a phase-screen propagation code for the paraxial wave equation. The advantages and limitations of the code are discussed. We show some time reversal results which demonstrate the super-resolution phenomenon and its statistical stability in the time domain. We also show results of imaging in random media using an array of active transducers.
Communication in a diffuse random medium with time-reversal techniques
Authors: Derode Arnaud , Tourin Arnaud , Tanter Mickael , Fink Mathias
Published: October 2013

The application of time-reversal focusing to communication in a diffuse random medium is discussed, and new experimental results are presented. Binary information was transmitted by using a 24-element time-reversal array, with a 3.2 central frequency, either in water or in a multiple scattering sample. The media we studied consisted of random collections of parallel steel rods immersed in water. Experiments show that it is possible to take advantage of high-order multiple scattering in order to transmit five different binary sequences to five different points simultaneously, which would be impossible to achieve in a homogeneous medium with the same antenna, due to its poor resolution. The results are discussed in relation with the numbers of significant singular values of the propagation matrix.
Noise propagation and prediction outdoors
Authors: Embleton Tony F. W.
Published: October 2013

Concerns about noise in the community date back to the dawn of recorded history, have continued through Roman times, the Middle Ages, and are still with us. Many of the principal wave-propagation mechanisms involved in the real atmosphere outdoors were understood at least qualitatively by the late 1800s. Today, a good understanding of all the sound propagation phenomena is of considerable economic and social importance in connection with environmental impact studies. Reality is far more intesting than simple spherical spreading in the space above a hard, flat ground. Some grounds are hard like concrete or soft as snow. Corresponding reflection coefficients are usually less than unity and vary with angle. Grounds may not be flat, leading to shadow zones or alternatively multiple reflected paths. Wind convects sound waves, and gradients of wind or temperature refract waves either upward (temperature lapse) or downward (inversion). The atmosphere is rarely still and turbulence causes fluctuations in the acoustical effects. All these features are frequency dependent, and mutually interact. Measured sound levels outdoors owe as much to near-surface weather and to ground shape as to the obvious acoustical factors of source and receiver heights and their separation. The discussion will emphasize field measurements and simple physical interpretations.
The enigma of fish ear diversity
Authors: Popper Arthur N. , Deng Xiaohong , Ramcharitar John , Higgs Dennis M.
Published: October 2013

There are substantial interspecific differences in the gross anatomy of fish inner ears, including the relative size of the different end organs and the sizes and shapes of their otoliths and sensory epithelia. Differences also occur at finer structural levels and include the orientation patterns of the ciliary bundles on the sensory hair cells. There is also substantial structural variation along the lengths of a single sensory epithelium. This includes not only the mode of contact between the sensory epithelium and the otolith, but also the lengths of the ciliary bundles on the hair cells, and the ultrastructure of the hair cell bodies themselves. The functional significance of the interspecific differences in ear structure is far from being understood, but it may reflect the evolution of different ways to do the same basic kinds of peripheral signal processing, or different kinds of signal processing. We also do not understand the functional importance of the intraepithelial differences, although they may suggest variance in signal processing along the lengths of single epithelia. This paper will consider all of these differences, and suggest ways in which we might think about their functional significance.
Acoustic measurement of oceanic turbulent kinetic energy dissipation rate, using a large-eddy technique
Authors: Gargett Ann E.
Published: October 2013

Turbulence in the ocean results from many different processes operating over a wide range of time and space scales, with spatial and temporal variability particularly extreme in coastal oceans. If origins and effects of turbulent processes in the ocean are to be understood, it is essential to supplement the small number of accurate measurements of turbulent properties produced by current microprofiler techniques. This talk will discuss a new acoustic large-eddy technique for estimating turbulent kinetic energy dissipation rate ε, using measurements of vertical velocity from a specialized Acoustic Doppler Current Profiler (ADCP). The method was calibrated against a subset of ε profiles taken during a single cruise with now-standard airfoil probes carried on a free-fall microprofiler. Without further adjustment of the calibration constant, the large-eddy acoustic estimates successfully describe the remaining profiler data from the same cruise, as well as data obtained with a different microscale profiler on a subsequent cruise. The new technique reveals the complexity of the field of ε in energetic coastal tidal fronts, on spatial and temporal scales which cannot be resolved by standard microprofiler measurements.
Observation of small scale fluid processes in the vicinity of continental shelf breaks using high-frequency acoustic backscattering systems
Authors: Orr Marshall H.
Published: October 2013

Acoustic signal vertical and horizontal coherence properties are controlled on the shelf and near the shelf break by a variety of flow induced fluid processes. These processes perturb the sound speed field at spatial scales of a few hundred meters and less. The frequency of occurrence, depth distribution, and the relationship of the sound speed field variability to both oceanic and atmospheric fluid processes occurring on the continental shelf is poorly understood and are not generally included in most acoustic propagation models. Acoustic flow visualization records collected on the continental shelf and at the shelf break in water depths ranging from 50–300 m will be presented. These records will show: (1) the types of internal wave and smaller scale turbulence that occur in the summer and early fall in the vicinity of the New Jersey shelf; (2) some observation of the dissipation of large amplitude internal waves at the shelf break of the South China Sea; and (3) a variety of small scale instabilities that can perturb the sound speed field. [Work supported by the ONR Ocean Acoustic Program and ONRs NRL base funding.]
Acoustic scatter from thermal plumes
Authors: Oeschger John
Published: October 2013

Laboratory results of high-frequency acoustic scattering measurements from a thermally driven plume are reported. Farfield weak scattering theory describes the acoustic scatter from the medium variability. To first order, the dominant scattering mechanism is thermally driven sound speed variations that are related to temperature deviations from ambient. As a result, the received complex acoustic scatter is a measure of the one-component three-dimensional Fourier transform of the temperature difference field measured at the Bragg wave number; this is the Fourier component of the plume variability that produces scattering. Results are presented for multistatic scattering from unstable and turbulent plumes using a parallel scattering geometry. Through common Bragg wave number comparisons, the data justify the application of the farfield weak scattering theory to the present case of a thermal plume. Results of temperature time series measurements taken of the plumes are also shown. Acoustical and mechanical temperature spectral estimates are presented and show a near-classical −11/3 power law behavior.
High intensity focused ultrasound treatment of abdominal tumors
Authors: ter Haar G. , Rivens I. , Allen M.
Published: October 2013

A phase II clinical trial for the treatment of isolated liver metastases is currently underway at the Royal Marsden Hospital. Tumors lying 4–12 cm below the skin surface are targeted in fully conscious patients. Treatment success is monitored using either radiological methods in conjunction with biochemical marker assays, or by histological examination. Factors determining pain or other sensations have been studied in order that exposures may be optimized. Laboratory investigations have been undertaken in parallel with these clinical studies, and these have been used to establish the effects of, for example, rib shadowing, timing of individual exposures, and in situ intensity on tissue ablation. Skin studies have allowed the determination of thresholds for a ‘‘burn’’ when multiple, overlapping exposures are used.
Transrectal focused ultrasound treatment of localized prostate cancer
Authors: Chapelon Jean-Yves , Souchon RTmi , Curiel Laura , Gelet Albert
Published: October 2013

Since 1989, a research project with the aim of establishing treatment of localized prostate cancer by means of high intensity focused ultrasound (HIFU) has been developed. The treatment of localized prostate cancer with HIFU, is administered transrectally, using ultrasound guidance only. The quality of the induced necrosis depends to a large extent on the choice of firing parameters: power, frequency, numbers and position of shots, shots duration, waiting time between shots and the shape of the acoustical field. The lesions are created by a thermal effect. Their slightly conical form is due to the absorption of the ultrasound wave by the tissues, increased by cavitation bubbles. Recently, it has been shown that real time elastography has the potential to accurately depict the ablated volume during a HIFU session, therefore providing feedback on the treatment. Results obtained since 1993 demonstrate that transrectal HIFU prostate ablation is an effective therapeutic alternative for patients with localized prostatic adenocarcinoma.
Ultrasonic monitoring of radiation-force deformation induced by therapeutic ultrasound
Authors: Lizzi Frederic L. , Muratore Robert , Deng Cheri X. , Mikaelian Samuel , Alam S. Kaisar , Ketterling Jeffrey A.
Published: October 2013

We have developed a dual-transducer technique to monitor tissue deformation induced by therapeutic ultrasound. The technique is designed to monitor and control therapeutic lesion size and location. Currently, the technique employs a spherical-cap high-intensity transducer with a central, co-linear diagnostic transducer. A-mode rf echo signals are first acquired using the diagnostic transducer to document pre-exposure conditions within the target tissue. A short (10 ms) intense exposure is then delivered with the spherical-cap transducer in order to induce tissue motion by radiation force. A-mode rf signals are then acquired for 0.2 s. Pre- and post-exposure A-mode signals are analyzed using correlation processing to determine the extent of induced tissue motion. The time constant associated with return to initial tissue positions is also calculated. These procedures have been applied in vitro to liver specimens using the spherical-cap transducer to periodically induce motion and to produce thermal lesions; at relatively low exposure levels, results are consistent with computer simulations. Larger exposures can produce permanent A-mode signal changes. We are optimizing this technique to enable it to validate therapy beam placement, to evaluate induced compression of vessels, and to monitor tissue rigidity changes that accompany thermal-lesion formation.
Thermoelastically actuated MEMS ultrasonic transducer
Authors: Chandrasekaran Venkataraman , Li Xi , Li Jian , Nishida Toshikazu , Cattafesta Louis N. , Sheplak Mark
Published: October 2013

Ultrasound based techniques provide a method for noncontact distance measurement utilizing a thin vibrating diaphragm as the acoustic source. Devices based on different operating principles have been reported including electrostatic and piezoelectric. The conventional pulse-echo technique is limited by a finite pulse decay time that restricts the measurement range to greater than a few centimeters. Proximity sensing on the order of millimeters can be achieved using continuous wave form techniques such as the acoustic impedance method or simultaneous excitation at multiple frequencies. Using silicon microfabrication technology, a MEMS ultrasonic transducer has been fabricated for millimeter range proximity sensing. The salient features of the sensor/actuator include a 0.01 mm thick, 1 mm diameter composite diaphragm that is thermoelastically driven at ultrasonic frequencies using a circular heater at its center. Dynamic Joulean heating of the diffused surface heater induces bending moments in the diaphragm due to the temperature gradient across the membrane cross section. Electromechanical transduction of the membrane vibration is achieved via four diffused silicon piezoresistive strain gauges located at the edge of the diaphragm. The design, fabrication and preliminary characterization of this sensor/actuator are presented.
Acoustic reflectometry in the manufacture of reproductions of historical wind instruments
Authors: Campbell D. Murray , Buick James M. , Kemp Jonathan A. , van Walstijn Maarten O.
Published: October 2013

Acoustic reflectometry has become a well-established technique for investigating the internal bore profile of cylindrically symmetrical ducts. Although the method has previously been applied with some success to the study of musical wind instrument bores, there are practical problems which limit the accuracy of bore reconstruction of instruments which are long or widely flaring, or which have side finger holes. This paper reports on a collaboration with Christopher Monk Instruments Ltd., a London-based firm specializing in the reproduction of cornetts and serpents. These are lip-reed instruments with side finger holes, and a curved bore center line which inhibits the use of conventional bore measuring techniques. It is demonstrated that acoustic reflectometry can provide bore profiles of these instruments with sufficient precision to be a valuable guide in their construction or repair. The precautions necessary to achieve this level of accuracy are described, and prospects for further refinements are discussed. [The collaboration of Keith Rogers and Jeremy West of CMI Ltd. is gratefully acknowledged. Work supported by the Engineering and Physical Sciences Research Council, U.K.]
Implementation of ANSI S12.60 acoustical performance criteria, design requirements and guidelines for schools
Authors: Thibault Lois E. L.
Published: October 2013

In 1997, the parent of a child with a hearing loss petitioned the U.S. Access Board to include guidelines for classroom acoustics in the accessibility guidelines the Board maintains under the ADA. The Board agreed that poor listening conditions in schools could be a barrier to the education of children with hearing impairments and other disabilities and arranged to collaborate with ASA and other stakeholders on an acoustical standard for classrooms. The Board will submit the completed standard to the International Codes Council for reference in the International Building Code adopted by many states and local jurisdictions, making it enforceable through the local permitting and inspections process. Reference in the ADA Accessibility Guidelines may follow in its next review cycle in 2005. Individualized Education Plans (IEPs) required under IDEA (Individuals with Disabilities Education Act) may also reference the new standard.
Flow and temperature fields in thermoacoustic stacks
Authors: Blanc-Benon Ph. , Duffourd S.
Published: October 2013

The paper describes the flow patterns and the temperature distribution measured in a thermoacoustic engine. Experiments have been performed in a resonant standing wave thermoacoustic refrigerator model. The knowledge of temperature and flow fields in the microchannels and at the edges of the stack plates becomes an increasingly important issue in the design of heat exchangers for thermoacoustic engines. Different geometries of the stack plates have been investigated as well as at different pressure levels. Heat exchangers have also been placed on both sides of the stack, with adjustable gaps. 2-D particle image velocimetry was used to investigate the flow with enlarged observation fields near the ends of the stack plates. We present velocity profiles across the microchannels, 2-D velocity fields. Vorticity maps were deduced using a criterion based on a normalized angular momentum. Vortex motion close to the stack ends has been clearly observed, however, with a strong influence of the plate thickness. An array of miniaturized thermocouples permits us to follow in real time the building-up of the temperature gradient along the stack for different oscillating flow conditions and different gaps between the stack and the heat exchangers. Finally, comparisons are made with theoretical models and numerical simulations recently published in the literature. [Work supported by DGA.]
A method for increasing the damping properties of fiber reinforced composite structures
Authors: Caiazzo Anthony A. , Rosen B. Walter
Published: October 2013

The passive material damping concept discussed in this paper is a sandwich construction of continuous fiber reinforced composite layers separated by a constrained visco-elastic material (VEM) layer. The fiber orientations in the composite layers are spatially oriented to produce systematic stiffness variations. It has been shown that three independent shear components may be developed in the VEM for simple applied loads using this spatially varying stiffness (SVS) approach, which is a distinct improvement over other traditional constrained layer treatments. To demonstrate predicted high-damping levels, modal loss factor data are presented for simple tubular and beam bending elements. Results of airborne sound transmission loss measurements on 1-m square SVS panels of various areal densities are described. Random vibration levels for an equipment mounting plate constructed using the SVS material are also presented and compared to results for a metallic base plate.