bluuebunny/crossref_metadata_2025 huggingface dataset:
Precise Wireless Triggering System for Anemometers with Long-Baseline Acoustic Probes
Authors: Wakatsuki Naoto , Kinjo Shin , Takarada Jun , Mizutani Koichi
Published: July 2010

A wireless triggering system for acoustic anemometers using an acoustic probe with a long baseline is investigated. Acoustic probes for measuring micrometeorologic parameters, such as temperature and wind velocity, are used as noncontact and nondestructive methods. The acoustic probe with a long baseline was previously proposed by the authors and investigated to form a sensing grid system for micrometeorologic measurement. The authors have also partially investigated a wireless sensing grid using a wireless local-area network (LAN). However, because of the synchronization problem between sensor nodes, the trigger line has been left wired. In this paper, the problem of synchronization is solved by investigating a wireless triggering system using frequency modulated (FM) radio waves. The primitive triggering system of FM radio waves has some instability on time synchronization depending on such the communication environment as signal-to-noise ratio (SNR). To overcome the influence of the instability, a cross-correlation method is adopted to the triggering system. As a result, the time synchronization errors of the trigger system were reduced by up to one tenth. In addition, not only the instability problem but also other larger errors are compensated by the proposed system in an experimental wind velocity measurement.
Lateral Detecting Limit of Underground Imaging Owing to Directivity of Sound Source
Authors: Toh Ryo , Motooka Seiichi
Published: July 2010

Considering the directivity of an electromagnetic-induction-type (EMI) sound source and the nonlinearity of the amplitude correlation synthesis processing (ACSP) method, the lateral detecting ability of the three-dimensional ACSP method for imaging objects buried underground is studied by both numerical simulation and experimental field testing. In both the numerical simulation and the experiment, three objects with identical dimensions buried at an identical depth are measured under six geometrical conditions with different spread angles from the EMI sound source. In addition, two underground objects with different lateral intervals are also imaged by the numerical simulation. The results of both the numerical simulation and the experiment indicate that the lateral detecting ability is mainly determined by the directivity of the EMI sound source and that the lateral detection of the imaging method is efficient for spread angles from the EMI sound source of less than about 35°.
Super-High-Frequency Band Filters Configured with Air-Gap-Type Thin-Film Bulk Acoustic Resonators
Authors: Hara Motoaki , Yokoyama Tsuyoshi , Sakashita Takeshi , Taniguchi Shinji , Iwaki Masafumi , Nishihara Tokihiro , Ueda Masanori , Satoh Yoshio
Published: July 2010

The first 24 and 30 GHz band thin-film bulk acoustic resonator (FBAR) filters are reported in this paper. The filters were configured with air-gap-type FBARs on a flat silicon substrate. They were designed using a Butterworth–Van-Dyke (BVD) equivalent circuit considering the linear relationship between resonant frequency, capacitance ratio, and loss in the FBAR. The measured characteristics corresponded with those of the simulation using the equivalent circuit in the pass-band. The center frequency, fractional bandwidth, minimum insertion loss, and out-of-band suppression were 23.8 GHz, 3.4%, -3.8 dB, and -13 dB in the 24 GHz band filter, and 29.2 GHz, 3.4%, -3.8 dB, and -11 dB in the 30 GHz band filter, respectively.
Optical Mode Converter Using Lamb Wave
Authors: Saito Koki , Nakagawa Yasuhiko , Kakio Shoji
Published: July 2010

A Lamb wave propagating through a crystal induces refractive-index variations in the crystal due to its photo-elastic effect; this crystal forms a phase cyclic structure. Therefore, if an incident light is transmitted into this crystal, light diffraction and mode transformation occur. In this study, we theoretically and experimentally examined light-wave propagation in a crystal in which Lamb waves had caused cyclic variations in the refractive index. In the experiment, it was verified that the Lamb wave power required for 100% mode conversion is 4 mW/mm in a LiTaO3 substrate with a Lamb wave wavelength of 132 µm and a substrate thickness of 50 µm.
Improvements in Temperature Characteristics and Bandwidth for ZnO/Quartz Structure with Large Coupling Factor
Authors: Murata Takaki , Kadota Michio , Matsuda Kenji , Kimura Tetsuya , Hashimoto Ken-ya
Published: July 2010

Recently, several applications have required radio frequency filters with a narrow bandwidth and high attenuations. A ZnO film/quartz structure has a good potential to such a requirement. In this paper, we show the optimization of the ZnO/quartz structure to obtain a nearly zero temperature coefficient of frequency (TCF) while maximizing the electro-mechanical coupling coefficient (k
2). In the previous papers published by one of the authors about the ZnO/quartz structure, a nearly zero TCF with a small electro-mechanical coupling coefficient, or non-zero TCF with maximized k
2 was reported. However, both zero TCF and maximized k
2 have not yet been simultaneously obtained. In this study, we investigated the optimized structure by calculation and also confirmed it by measurement.
Sonoluminescence of Alkali-Metal Atoms in Sulfuric Acid: Comparison with That in Water
Authors: Hatanaka Shin-ichi , Hayashi Shigeo , Choi Pak-Kon
Published: July 2010

Intense orange Na* emission was observed in different spatial locations from blue emission during multibubble sonoluminescence in sulfuric acid. The color change from blue to orange was observed along the streamer in the filamentous structure of a bubble cloud. By stroboscopic observation, the Na* emission seemed to occur when a large bubble ejected tiny bubbles at the positions toward a pressure node after bubble coalescence around a pressure antinode. The intensity of Na* emission in the sulfuric acid case increased at lower frequency in contrast with the water case. By comparing a high-resolution Na* spectrum of sulfuric acid with that of water, the widths of the spectra were almost the same, except for something being superimposed in the water case. The estimations of the temperature and pressure inside the Na* emission bubbles at 28 and 150 kHz were 1900 K and 100 atm and 2200 K and 150 atm, respectively.
Effect of Ultrasonic Frequency on Enzymatic Hydrolysis of Cellulose
Authors: Yasuda Keiji , Kato Daiki , Xu Zheng , Sakka Makiko , Sakka Kazuo
Published: July 2010

The effect of ultrasonic frequency on the enzymatic hydrolysis of cellulose was examined. As the cellulose and enzyme, needle unbleached kraft pulp and cellulase were used. In the cases of the horn-type transducer at 20 kHz and the plate-type transducer at 28 kHz, the enzymatic hydrolysis was accelerated by ultrasonic irradiation. Total sugar concentration linearly increased with ultrasonic intensity. On the other hand, in the case of the plate-type transducer at 500 kHz, the enzymatic hydrolysis was inhibited. Total sugar concentration decreased with increasing ultrasonic intensity.
Effect of Ultrasound on Bisphenol A Adsorption on the Granular Activated Carbon
Authors: Lim Myunghee , Son Younggyu , Cui Mingcan , Khim Jeehyeong
Published: July 2010

The aim of this study is to investigate the effects of ultrasound (power, frequency) on bisphenol A (BPA) adsorption on granular activated carbon (GAC). The result of adsorption isotherm in a BPA solution, using sonicated GAC (at 35 kHz) can more successfully adsorb BPA than sonicated GAC (at 300 kHz) and the original GAC. At low frequency GAC has a high cavitation effect. Therefore, the amount of adsorbed BPA at a low frequency was higher than at a high frequency. In isotherm experiments, ultrasound can enhance the adsorption process in GAC in both frequencies (35 and 300 kHz). These results agree with other previous researches. The effect of power intensity in the adsorption of BPA is increased the adsorption of BPA with increasing power. The optimum power exists and differs from frequencies because the cavitation effect is not the same with different frequencies.
Study of an Acoustic Field in a Microchannel
Authors: Kozuka Teruyuki , Yasui Kyuichi , Hatanaka Shin-ichi , Tuziuti Toru , Lee Judy , Towata Atsuya
Published: July 2010

Using a standing-wave field, it is possible to trap small objects at nodes of a sound pressure distribution. In the present study, a sound wave was generated by a transducer outside of a microchannel, and propagated into a microchannel on a glass plate, where it generated a standing wave field. When water containing alumina particles was injected into the microchannel, several layers of particles were formed in the sound field. Moreover, when the ultrasound driving frequency was swept, it was possible to control the direction of the particle flow. The sound field was numerically calculated and the experimental results are discussed.
Modeling of Parametric Loudspeakers by Gaussian-Beam Expansion Technique
Authors: Ye Chao , Wu Ming , Wu Shuaibin , Huang Chenxi , Yang Jun
Published: July 2010

A quasi-linear analytical solution based on the Gaussian-beam expansion technique is used to model the parametric array. The axial sound pressure levels and the beam pattern of the primary and difference frequency waves of a compact hexagonal array, a spaced hexagonal array and a conventional square array consisting of circular elements are calculated. For comparison, a square piston source with equal radiation area is considered as well. Simulation results show that the beam patterns of the difference frequency sound of four sources are almost the same. The compact hexagonal array is more efficient than the square array because of higher axial sound pressure levels of the difference frequency sound.
Investigation of Miniature Cantilever-Type Ultrasonic Motor Using Lead-free Array-Type Multilayer Piezoelectric Ceramics
Authors: Doshida Yutaka , Shimizu Hiroyuki , Irieda Taisei , Tamura Hideki , Tomikawa Yoshiro , Hirose Seiji
Published: July 2010

We studied the following to clarify the design rule of the miniature cantilever-type ultrasonic motor using lead-free array-type multilayer piezoelectric ceramics, which is (Sr,Ca)2NaNb5O15. The relationship between the motor properties and stator vibrator dimensions was investigated by the finite element method and vibration analysis. The motor properties mainly depended on the cantilever sizes. The motor properties can be especially controlled from the revolution-speed-oriented type to the torque-oriented type by adjusting the vamplate radius of the cantilever. As a result, the design rule was clarified. In accordance with the design rule, the lead-free torque-oriented motor was fabricated and its properties were evaluated. The driving properties of this motor changed to the torque-oriented characteristics, such as the ratio of the maximum torque to the maximum speed was over 1200-fold of that of the motor fabricated in a previous study. It appeared that the driving properties of the lead-free cantilever-type motor can be controlled by using the design rule.
Staircase-Voltage Metal–Oxide–Semiconductor Field-Effect Transistor Driver Circuit for Therapeutic Ultrasound
Authors: Moro Kosuke , Yoshizawa Shin , Umemura Shin-ichiro
Published: July 2010

An important component of all ultrasound systems is the high-voltage pulse generator used to excite the transducer. We created a new type of metal–oxide–semiconductor field-effect transistor (MOSFET) switching circuit for therapeutic ultrasound applications, on the basis of the staircase-voltage drive concept. The staircase drive can significantly decrease the harmonics in comparison with the conventional square-wave drive. Since it does not require a resonant circuit to improve the efficiency, the drive frequency can be freely changed and the total size of the drive circuit can be made smaller. Using a diode in series to the drain of each MOSFET, a staircase-voltage driver was created with a relatively simple configuration. The experimental results of operating a prototype driver, as well as the results from circuit simulation, are discussed.
Acoustic Impedance Evaluation of High-Intensity-Focused-Ultrasound Exposed Chicken Breast Muscle Using Ultrasonic Microscopy
Authors: Shishitani Takashi , Yoshizawa Shin , Umemura Shin-ichiro
Published: July 2010

High-intensity focused ultrasound (HIFU) surgery is one of the non-invasive therapeutic methods. The high temperature generated by this method coagulates the target non-superficial tissue. In this study, we evaluate the effect of thermal coagulation by HIFU on acoustic impedance. Chicken breast muscle was used as the specimen. Acoustic impedance was measured in cross sections of the HIFU-exposed specimen using an ultrasonic microscope. The acoustic impedance of the coagulated region was significantly lower than that of the non-coagulated region.
Blood Flow Measurement by the Counter-Crossed Beam Contrast Echo Method
Authors: Eura Taishi , Yoshida Kenji , Watanabe Yoshiaki , Akiyama Iwaki
Published: July 2010

We propose a new contrast-echo method using the counter-crossed beams of two ultrasonic frequencies for ultrasound diagnosis of cancer and call it the counter-cross beam contrast echo (C-CBCE) method. In this C-CBCE method, the sum- or difference-frequency components generated by the nonlinear vibration of microbubbles driven by dual-frequency ultrasound are used for measuring flow velocity. The C-CBCE method has the potential to measure low blood flow velocities, since the echo from the blood flow is efficiently separated from the echo from the biological soft tissues using the sum- or difference-frequency component. Sonazoid is used as microbubbles, and the sum frequency is used in the experiments. We prototyped the measurement system, which consists of commercially available ultrasound diagnostic equipment with a convex array probe and another ultrasonic probe, in order to determine the feasibility of the C-CBCE method in clinical diagnosis. In this study, we employ the C-CBCE method to measure the flow velocity of microbubbles in a channel using the sum-frequency component generated by the nonlinear vibration of microbubbles. We demonstrate theoretically the relationship between the Doppler-shift frequency of the sum-frequency component and the flow velocity in a channel. In order to confirm the theory on which this method is based, we then determine flow velocities on the basis of the sum-frequency component, fundamental component, and second-harmonic component.
Production of Local Acoustic Radiation Force to Constrain Direction of Microcapsules in Flow
Authors: Masuda Kohji , Watarai Nobuyuki , Nakamoto Ryusuke , Muramatsu Yusuke
Published: July 2010

We have ever reported our attempt to control the direction of microcapsules in flow by acoustic radiation force. However, the diameter of capsules was too large to be applied in vivo. Furthermore, the acoustic radiation force affected only the focal area because focused ultrasound was used. Thus, we have improved our experiment by using microcapsules as small as blood cells and introducing a plane wave of ultrasound. We prepared an artificial blood vessel including a Y-form bifurcation established in two observation areas. Then, we newly defined the induction index to evaluate the difference in capsule density in two downstream paths. As a result, the optimum angle of ultrasound emission to induct to the desired path was derived. The induction index increased in proportion to the central frequency of ultrasound, which is affected by the aggregation of capsules to receive more acoustic radiation force.
Precise Vascular Visualization in Ultrasonic Power Doppler Imaging with Motion Compensation
Authors: Yoshikawa Hideki , Azuma Takashi , Kawabata Ken-ichi
Published: July 2010

Motion-compensated ultrasonic power Doppler imaging (MC-PDI) is established, in which motion compensation (MC) is applied to frame persistence utilized in conventional ultrasonic power Doppler imaging (PDI). In the Doppler phantom experiment, MC was found to enable the taking of blurless power Doppler (PD) images upon target motion at a high speed for conventional PDI (> 5 mm/s). The effect of MC was further found to be independent of the number of frames for persistence. In the tissue experiments, a healthy human kidney, a healthy liver, and a tumor implanted into the rabbit liver, the blood vessels with a diameter of 1 mm or less could be precisely visualized by MC-PDI. An index of the resolution of two blood vessels was defined and it was found that the index for MC-PDI was 2.6 times better than that for conventional PDI of the kidney. These experiments indicate the capability of MC-PDI for precise and blur-free vascular visualization.
Medical Ultrasound Imaging Using Pulse Compression Technique Based on Split and Merge Strategy
Authors: Tanabe Masayuki , Yamamura Takuya , Okubo Kan , Tagawa Norio
Published: July 2010

A medical ultrasound image with a high spatial resolution and a high signal-to-noise ratio (SNR) is required for precise diagnosis. However, when a long chirp pulse is transmitted in order to improve the SNR, both the transmitted signal and the echo signal overlap. The dynamic range of the analog-to-digital (A/D) converter should be adjusted to that of the echo signal, and the transmitted pulse is saturated. Therefore, the transmitted pulse cannot be compressed completely, and the echo signal cannot be extracted from the overlapped signal. This indicates that a long chirp signal makes near-field imaging impossible. In this paper, we propose a method that can realize near- and far-field imaging processes with higher SNRs. The proposed method is based on a split-and-merge strategy. As a result, it is shown that our proposed method gives both near- and far-field images with approximately 40 dB higher SNRs than the short pulse.
Effect of Pretrapping of Microbubbles in Sonoporation Using N-Isopropylacrylamide Gel Flow Channel Phantom
Authors: Yamakoshi Yoshiki , Miwa Takashi , Yoshizawa Nobuyuki , Inoguchi Hiroki , Zhang Dongyu
Published: July 2010

It is considered that sonoporation, which produces small pores through a cell membrane, is a sophisticated tool for improving the efficacy of ultrasonic-wave-irradiated drug delivery systems. However, neither the precise mechanism of pore production nor the optimum conditions of insonation have been clarified yet. In this study, the microscopic observation of micron size hollows produced on the wall of an optical transparent gel by bubble cavitation is performed in order to evaluate sonoporation. As a gel phantom, we adopted N-isopropylacrylamide (NIPA) gel, which has almost the same acoustic properties as soft tissue and is optically transparent below the metastasis temperature. Using the gel phantom, the effect of the pretrapping of microbubbles, which is carried out immediately before irradiating a high-intensity ultrasonic wave to prepare the bubble conditions required for sonoporation, is evaluated.
Acoustic Response of Microbubbles Derived from Phase-Change Nanodroplet
Authors: Kawabata Ken-ichi , Asami Rei , Azuma Takashi , Umemura Shin-ichiro
Published: July 2010

An in vitro feasibility test for a novel ultrasound therapy using a type of superheated perfluorocarbon droplet, phase-change nanodroplet (PCND), was performed in gel phantoms with the goal of high selectivity and low invasiveness. Measurements of broadband signal emission revealed that a triggering ultrasound pulse (peak negative pressure of 2.4 MPa) reduces the pressure threshold for cavitation induced by a subsequent ultrasound exposure at an order of magnitude from 2.4 to 0.2 MPa. The maximum allowed interval between the two ultrasound exposures for inducing cavitation with 100- and 1,000-cycle triggering ultrasound was about 100 and 500 ms, respectively. The echo signal increases induced by the triggering ultrasound with 100- and 1000-cycles were enhanced and suppressed by the subsequent ultrasound exposure, respectively. This different behavior seemed to be due to the presence of enlarged free bubbles, which should be avoided for the localization of therapeutic effects.
Optical Scattering Measurement of Microbubble Cloud Dynamics in Ultrasound
Authors: Miwa Takashi , Yamakoshi Yoshiki , Mashiyama Tomoharu
Published: July 2010

The manipulation of microbubbles by ultrasonic waves has the potential to be a useful technique in therapeutic ultrasound, such as for drug delivery systems and gene delivery systems. The Bjerknes force, which is an acoustic radiation force produced by microbubbles, acts as a driving force on the microbubbles; however, the two types of Bjerknes force make the resultant bubble movement very complex. In this paper, the evaluation of microbubble dynamics under ultrasonic wave radiation based on a laser diffraction method is proposed. The relationship between the microbubble spatial distribution and the diffracted light intensity is discussed on the basis of both theoretical analysis and numerical simulations. Experiments are carried out using ultrasonic wave contrast agent as microbubbles.
Sustaining Microbubbles Derived from Phase Change Nanodroplet by Low-Amplitude Ultrasound Exposure
Authors: Kawabata Ken-ichi , Asami Rei , Yoshikawa Hideki , Azuma Takashi , Umemura Shin-ichiro
Published: July 2010

To improve the short lifetime of microbubbles induced upon application of triggering ultrasound pulse to a phase change nanodroplet (PCND), the effect of low-pressure continuous ultrasound for sustaining microbubbles was studied in a gel phantom. A pulse with 100 cycles of 1.1 MHz ultrasound with a peak negative pressure of 2.4 MPa was used for the generation of microbubbles while superimposing a bubble-sustaining ultrasound at a frequency of 1.1 MHz with a relatively low-pressure amplitude. It was found that a peak negative pressure in the range from 0.01 to 0.1 MPa was suitable for sustaining the microbubbles without inducing cavitation. The presence of sustained bubbles could be echographycally observed as a beam-shaped brightness change. Moreover, the sustained microbubbles induced cavitation upon additional application of ultrasound pulse at a peak negative pressure of 0.2 MPa. The results obtained suggested that not only the lifetime but also the activity of the microbubbles can be controlled.
Enhancement of Localized Heating by Ultrasonically Induced Cavitation in High Intensity Focused Ultrasound Treatment
Authors: Takagi Ryo , Yoshizawa Shin , Umemura Shin-ichiro
Published: July 2010

There are reports that ultrasonically induced cavitation bubbles locally enhance tissue heating in high intensity focused ultrasound (HIFU) treatment. In this study, a high-intensity burst (named “a triggering pulse”) above the cavitation threshold was used to trigger cavitation. Immediately after that, CW ultrasound (named “heating waves”), at an intensity level and duration typical for conventional HIFU ablation was irradiated. Before the ablating sonication, it is necessary to determine the optimum intensity and duration of the triggering pulse. Immediately after a test triggering pulse, low-intensity CW ultrasound (named “a sustaining pulse”) was irradiated for a short duration of time, and we detected the cavitation noises (subharmonics and higher harmonics) generated in the focus spot. The relationship between the 1/2 subharmonic signal amplitude and the coagulation volume after the ablating sonication was investigated. The result of this experiment suggests that we can optimize the triggering pulse by detecting the 1/2 subharmonic signal amplitude.
Wavelet Transform Analysis of Ultrasonic Wave Propagation in Cancellous Bone
Authors: Hasegawa Sho , Nagatani Yoshiki , Mizuno Katsunori , Matsukawa Mami
Published: July 2010

Ultrasonic waves targeted on cancellous bone separates into fast and slow waves according to the alignment of bone trabeculae. The characteristics of the specimen, however, can sometimes result in ambiguous wave separation. In this study, we proposed using wavelet transform as a new method of analyzing ultrasonic waveforms. Using continuous wavelet transform, two components were separated by fitting two-dimensional Gaussian function in scalogram. The relationship between bone volume fraction and the peak amplitude of the lower- and higher-frequency components showed a clear negative correlation; conversely, the relationship between bone volume fraction and the peak value ratio of the lower- and higher-frequency components showed a positive correlation. We recoginized lower-frequency component as the multiple reflections (forward scattering) in cancellous bone.
Perception Mechanisms of Bone-Conducted Ultrasound Assessed by Acoustic Characteristics in the External Auditory Meatus
Authors: Ito Kazuhito , Nakagawa Seiji
Published: July 2010

Acoustic fields/vibrations in the external auditory meatus (ear canal) and tympanic membrane (TM) under bone-conducted ultrasonic stimulation were measured to elucidate the contributions of the osseotympanic and inertial routes to bone-conducted ultrasonic (BCU) perception. Evidence showing nonlinear distortions, especially the generation of audible subharmonics in the outer and middle ear, was examined. In the results, we did not find any audible signals corresponding to the subjective pitch of a BCU tone in the acoustic fields for the auditory meatus and TM vibrations. This suggests that nonlinear distortions in the osseotympanic and inertial routes do not contribute to bone-conducted ultrasonic perception. Specific properties of perception may be related to mechanisms in the cochlea or afferent neural pathway.
Imaging Performance Evaluation Method of Wide-View Underwater Acoustic Lens by Geometrical Skew Ray Analysis
Authors: Matsumoto Sayuri , Takeyama Norihide , Tsuchiya Takenobu , Endoh Nobuyuki
Published: July 2010

In the image formation performance of an underwater acoustic lens, the use of geometrical skew ray analysis for usually use in optical lens design field was examined. We measured acoustic pressure fields through a single lens, from which the acoustic energy distribution was obtained by using encircled energy. On the other hand, the analyzed acoustic energy distribution was evaluated by geometrical skew ray analysis under the measurement condition including the apodization of the source and effect of water temperature. We compared the measured and analyzed convergence positions, which the diameter of 80% of total amount of acoustic energy is the minimum. Then the both convergence positions correspond. As a result, it was shown that the image performance evaluation of a wide-view acoustic lens by geometrical skew ray analysis is useful.
Snapping Shrimp Sound Measured Under Laboratory Conditions
Authors: Kim Byoung-Nam , Hahn Jooyoung , Choi Bok Kyoung , Kim Bong-Chae
Published: July 2010

The typical temporal waveforms and spectra of the sounds produced by the three species of snapping shrimp with different claw shapes and almost the same claw lengths were investigated under laboratory conditions. The sound spectra generated by one species of snapping shrimp were also investigated for various claw lengths. For the three species of snapping shrimp, their typical temporal waveforms were similar, but their sound spectra and pulse durations differed. This difference was related to the size of the single cavitation bubble, which was generated by the high-speed water jet emitted from the snapping shrimp claw. The range of difference in the times between the snapping shrimp claw closure and the collapse of the single cavitation bubble for the three species of snapping shrimp seemed to be determined by the difference in the claw shape. The collapse time, the equilibrium radius, and the maximal radius of the cavitation bubble for each species were estimated from the first peak frequency component in the snapping shrimp sound spectrum. For one species of snapping shrimp, the peak frequency components in the sound spectra were observed for various claw lengths and their superposition could be considered as the cause that the broad peak frequency components were variously observed in the averaged snapping shrimp sound spectra, which were measured in many shallow water areas.
Wideband Tonpilz Transducer with a Cavity Inside a Head Mass
Authors: Chhith Saosometh , Roh Yongrae
Published: July 2010

A multimode Tonpilz transducer is well-known for providing a wider bandwidth than a single-mode transducer. In this paper, a new structure for the head mass of a multimode Tonpilz transducer was designed to further widen the bandwidth. The mechanical quality factor of a Tonpilz transducer is proportional to the weight of its head mass. In that sense, making the cavity inside the head mass will surely lead to a much lighter head mass, which can lead to a lower mechanical quality factor, thus a wider bandwidth. Through finite element analyses, the effects of the void head mass structure on the transducer performance were analyzed, and the dimension of the cavity to achieve the widest bandwidth was determined within given structural variation ranges. The variation ranges were selected as those in which the coefficient of determination in regression analyses was larger than 0.95 over all the ranges. The structure of a tail mass was also designed using the same method to match the new head mass.
Basic Study of Orthogonal Signal Division Multiplexing for Underwater Acoustic Communication: A Comparative Study
Authors: Ebihara Tadashi , Mizutani Koichi , Wakatsuki Naoto
Published: July 2010

Underwater acoustic (UWA) communication in shallow water has been challenging owing to multipath-induced signal distortion and motion-induced Doppler distortion. In this study, we investigate the performance of a UWA communication system using orthogonal signal division multiplexing (OSDM) on intersymbol interference (ISI) and Doppler shift in a simulation, by comparing it with an existing communication system that uses coherent modulation with an adaptive filter, to clarify whether OSDM is suitable for UWA communication in shallow water. The obtained results clarify that OSDM is robust to heavy ISI, and it is expected to be suitable for a rapidly time-varying channel. For example, OSDM can improve the output signal-to-noise ratio (SNR) of 9.4 dB in a shallow water channel with a multipath delay time dispersion of 20 symbols, compared with the UWA communication system with decision feedback equalizer (DFE). However, it is also clarified that OSDM is more sensitive to the Doppler effect compared with the existing communication system, and there is the necessity of applying frequency-offset compensation, because the permissible Doppler shift, when the output SNR falls to -3 dB, for OSDM is less than half that for the UWA communication system with DFE.
Reducing Intercarrier Interference for Orthogonal Frequency Division Multiplexing
Authors: Lin Chundan , Chen Mian , Zhang Wansong , Park Jihyun , Yoon Jong Rak
Published: July 2010

Orthogonal frequency division multiplexing (OFDM) is very sensitive to the frequency offset that causes intercarrier interference (ICI). A multiple symbol encapsulated orthogonal frequency division multiplexing (MSE-OFDM) system with a self inter-carrier interference (ICI) cancellation scheme is proposed to reduce the ICI effect and increase the bandwidth efficiency. Performance analysis shows that this proposed system can cancel ICI effectively and is particularly suitable for channels with long impulse response.
Reciprocal Sound Propagation Experiment in Very Shallow Water Area of Hashirimizu Port
Authors: Ogasawara Hanako , Mori Kazuyoshi , Nakamura Toshiaki
Published: July 2010

A fundamental experiment for environmental monitoring using reciprocal sound propagation was conducted in a very shallow water area in Hashirimizu Port near the entrance to Tokyo Bay. Sound propagation systems with a 12.5 kHz transducer were placed at opposite piers with a distance of about 120 m. Sound travel time was monitored using M-sequence phase-modulated signals so that an accurate arrival time could be detected even in a noisy environment. Arrival time changed throughout the experiment period about 3 weeks almost in accordance with the changes in seawater temperature. However, under certain conditions, such as a low tide and a high negative gradient of the temperature profile in the depth direction, the arrival time was longer than expected. Ray tracing calculation using Bellhop revealed that all rays radiated by the transducer were refracted downward because of the sound speed profile changes. It turns out that the ray path changes depending on ocean environmental changes, especially changes in temperature and the tides. Current speed estimation from reciprocal travel time showed a trend similar to the measurement result of the acoustic doppler current profiler (ADCP). The low reliability of current can be improved by changing the peak tracking method. It also has a potential to get wide area of ocean environment using reflected waves.
A large-scale study on map search logs
Authors: Xiao Xiangye , Luo Qiong , Li Zhisheng , Xie Xing , Ma Wei-Ying
Published: July 2010

Map search engines, such as Google Maps, Yahoo! Maps, and Microsoft Live Maps, allow users to explicitly specify a target geographic location, either in keywords or on the map, and to search businesses, people, and other information of that location. In this article, we report a first study on a million-entry map search log. We identify three key attributes of a map search record—the keyword query, the target location and the user location, and examine the characteristics of these three dimensions separately as well as the associations between them. Comparing our results with those previously reported on logs of general search engines and mobile search engines, including those for geographic queries, we discover the following unique features of map search: (1) People use longer queries and modify queries more frequently in a session than in general search and mobile search; People view fewer result pages per query than in general search; (2) The popular query topics in map search are different from those in general search and mobile search; (3) The target locations in a session change within 50 kilometers for almost 80% of the sessions; (4) Queries, search target locations and user locations (both at the city level) all follow the power law distribution; (5) One third of queries are issued for target locations within 50 kilometers from the user locations; (6) The distribution of a query over target locations appears to follow the geographic location of the queried entity.
Privacy-preserving query log mining for business confidentiality protection
Authors: Poblete Barbara , Spiliopoulou Myra , Baeza-Yates Ricardo
Published: July 2010

We introduce the concern of confidentiality protection of business information for the publication of search engine query logs and derived data. We study business confidentiality, as the protection of nonpublic data from institutions, such as companies and people in the public eye. In particular, we relate this concern to the involuntary exposure of confidential Web site information, and we transfer this problem into the field of privacy-preserving data mining. We characterize the possible adversaries interested in disclosing Web site confidential data and the attack strategies that they could use. These attacks are based on different vulnerabilities found in query log for which we present several anonymization heuristics to prevent them. We perform an experimental evaluation to estimate the remaining utility of the log after the application of our anonymization techniques. Our experimental results show that a query log can be anonymized against these specific attacks while retaining a significant volume of useful data.
Lipins: Multifunctional Lipid Metabolism Proteins
Authors: Csaki Lauren S. , Reue Karen
Published: July 2010

The lipin proteins are evolutionarily conserved proteins with roles in lipid metabolism and disease. There are three lipin protein family members in mammals and one or two orthologs in plants, invertebrates, and single-celled eukaryotes. Studies in yeast and mouse led to the identification of two distinct molecular functions of lipin proteins. Lipin proteins have phosphatidate phosphatase activity and catalyze the formation of diacylglycerol in the glycerol-3-phosphate pathway, implicating them in the regulation of triglyceride and phospholipid biosynthesis. Mammalian lipin proteins also possess transcriptional coactivator activity and have been implicated in the regulation of metabolic gene expression. Here we review key findings in the field that demonstrate roles for lipin family members in metabolic homeostasis and in rare human diseases, and we examine evidence implicating genetic variations in lipin genes in common metabolic dysregulation such as obesity, hyperinsulinemia, hypertension, and type 2 diabetes.
Fatty Acid Supply to the Human Fetus
Authors: Haggarty Paul
Published: July 2010

Deposition of fat in the fetus increases exponentially with gestational age, reaching its maximal rate—around 7 g/day or 90% of energy deposition—at term. In late pregnancy, many women consuming contemporary Western diets may not be able to meet the fetal demand for n-3 long chain polyunsaturated fatty acids (LCPUFAs) from the diet alone. Numerous mechanisms have evolved to protect human offspring from extreme variation or deficiency in the maternal diet during pregnancy. Maternal adipose tissue is an important source of LCPUFA. Temporal changes in placental function are synchronized with maternal metabolic and physiological changes to ensure a continuous supply of n-3 and n-6 LCPUFA-enriched fat to the fetus. LCPUFA storage in fetal adipose tissue provides an important source of LCPUFA during the critical first months of postnatal life. An appreciation of these adaptations is important in any nutritional strategy designed to improve the availability of fatty acids to the fetus.
Iron-Sensing Proteins that Regulate Hepcidin and Enteric Iron Absorption
Authors: Knutson Mitchell D.
Published: July 2010

The human body cannot actively excrete excess iron. As a consequence, iron absorption must be strictly regulated to ensure adequate iron uptake and prevent toxic iron accumulation. Iron absorption is controlled chiefly by hepcidin, the iron-regulatory hormone. Produced by the liver and secreted into the circulation, hepcidin regulates iron metabolism by inhibiting iron release from cells, including duodenal enterocytes, which mediate the absorption of dietary iron. Hepcidin production increases in response to iron loading and decreases in iron deficiency. Such regulation of hepcidin expression serves to modulate iron absorption to meet body iron demand. This review discusses the proteins that orchestrate hepatic hepcidin production and iron absorption by the intestine. Emphasis is placed on the proteins that directly sense iron and how they coordinate and fine-tune the molecular, cellular, and physiologic responses to iron deficiency and overload.
Micronutrients, Birth Weight, and Survival
Authors: Christian Parul
Published: July 2010

Maternal micronutrient requirements during pregnancy increase to meet the physiologic changes in gestation and fetal demands for growth and development. Maternal micronutrient deficiencies are high and coexist in many settings, likely influencing birth and newborn outcomes. The only recommendation for pregnancy currently exists for iron and folic acid use. Evidence is convincing that maternal iron supplementation will improve birth weight and perhaps gestational length. In one randomized trial, iron supplementation during pregnancy reduced child mortality in the offspring compared with the control group. Few other single micronutrients given antenatally, including vitamin A, zinc, and folic acid, have been systematically shown to confer such a benefit. A meta-analysis of 12 trials of multiple micronutrient supplementation compared with iron-folic acid reveals an overall 11% reduction in low birth weight but no effect on preterm birth and perinatal or neonatal survival. Currently, data are unconvincing for replacing supplementation of antenatal iron-folic acid with multiple micronutrients.
Between Death and Survival: Retinoic Acid in Regulation of Apoptosis
Authors: Noy Noa
Published: July 2010

The vitamin A metabolite all-trans-retinoic acid (RA) regulates multiple biological processes by virtue of its ability to regulate gene expression. It thus plays critical roles in embryonic development and is involved in regulating growth, remodeling, and metabolic responses in adult tissues. RA can also suppress carcinoma cell growth and is currently used in treatment of some cancers. Growth inhibition by RA may be exerted by induction of differentiation, cell cycle arrest, or apoptosis, or by a combination of these activities. Paradoxically, in the context of some cells, RA not only fails to inhibit growth but, instead, enhances proliferation and survival. This review focuses on the involvement of RA in regulating apoptotic responses. It includes brief overviews of transcriptional signaling by RA and of apoptotic pathways, and then addresses available information on the mechanisms by which RA induces apoptosis or, conversely, inhibits cell death and enhances survival.
Sedation and Analgesia in Children with Developmental Disabilities and Neurologic Disorders
Authors: Kilbaugh Todd J. , Friess Stuart H. , Raghupathi Ramesh , Huh Jimmy W.
Published: July 2010

Sedation and analgesia performed by the pediatrician and pediatric subspecialists are becoming increasingly common for diagnostic and therapeutic purposes in children with developmental disabilities and neurologic disorders (autism, epilepsy, stroke, obstructive hydrocephalus, traumatic brain injury, intracranial hemorrhage, and hypoxic-ischemic encephalopathy). The overall objectives of this paper are (1) to provide an overview on recent studies that highlight theincreasedrisk for respiratory complications following sedation and analgesia in children with developmental disabilities and neurologic disorders, (2) to provide a better understanding of sedatives and analgesic medications which are commonly used in children with developmental disabilities and neurologic disorders on thecentral nervous system.
Contribution of Isoprene Oxidation Products to Marine Aerosol over the North‐East Atlantic
Authors: Anttila Tatu , Langmann Baerbel , Varghese Saji , O′Dowd Colin
Published: July 2010

Secondary organic aerosol (SOA) formation through isoprene oxidation was investigated with the regional‐scale climate model REMOTE. The applied modeling scheme includes a treatment for marine primary organic aerosol emissions, aerosol microphysics, and SOA formation through the gas/particle partitioning of semivolatile, water‐soluble oxidation products. The focus was on SOA formation taking place over the North‐East Atlantic during a period of high biological activity. Isoprene SOA concentrations were up to ~5 ng m−3 over North Atlantic in the base case model runs, and isoprene oxidation made a negligible contribution to the marine organic aerosol (OA) mass. In particular, isoprene SOA did not account for the observed water‐soluble organic carbon (WSOC) concentrations over North Atlantic. The performed model calculations, together with results from recent field measurements, imply a missing source of SOA over remote marine areas unless the isoprene oxidation products are considerably less volatile than the current knowledge indicates.
Factors Associated with Increased Risk Perception of Pandemic Influenza in Australia
Authors: Jacobs Jennifer , Taylor Melanie , Agho Kingsley , Stevens Garry , Barr Margo , Raphael Beverley
Published: July 2010

The aim of this study was to assess factors associated with increased risk perception of pandemic influenza in Australia. The sample consisted of 2081 Australian adults aged 16 years and older who completed a short three item pandemic influenza question module which was incorporated into the NSW Health Adult Population Health Survey during the first quarter of 2007. After adjusting for covariates, multivariate analysis indicated that those living in rural regions were significantly more likely to perceive a high risk that a pandemic influenza would occur, while those with poor self-rated health perceived both a high likelihood of pandemic and high concern that self/family would be directly affected were such an event to occur. Those who spoke a language other than English at home and those on low incomes and younger people (16–24 years) were significantly more likely to have changed the way they lived their lives due to the possibility of pandemic influenza, compared to those who spoke only English at home, middle-high income earners, and older age groups, respectively. This data provides an Australian population baseline against which the risk perceptions of demographic subgroups regarding the current, and potential future pandemics, can be compared and monitored.
MET Kinase Inhibitor SGX523 Synergizes with Epidermal Growth Factor Receptor Inhibitor Erlotinib in a Hepatocyte Growth Factor–Dependent Fashion to Suppress Carcinoma Growth
Authors: Zhang Yu-Wen , Staal Ben , Essenburg Curt , Su Yanli , Kang Liang , West Rich , Kaufman Dafna , DeKoning Tom , Eagleson Bryn , Buchanan Sean G. , Vande Woude George F.
Published: July 2010

The hepatocyte growth factor (HGF)-MET pathway supports several hallmark cancer traits, and it is frequently activated in a broad spectrum of human cancers (http://www.vai.org/met/). With the development of many cancer drugs targeting this pathway, there is a need for relevant in vivo model systems for preclinical evaluation of drug efficacy. Here, we show that production of the human HGF ligand in transgenic severe combined immunodeficient mice (hHGFtg-SCID mice) enhances the growth of many MET-expressing human carcinoma xenografts, including those derived from lung, breast, kidney, colon, stomach, and pancreas. In this model, the MET-specific small-molecule kinase inhibitor SGX523 partially inhibits the HGF-dependent growth of lung, breast, and pancreatic tumors. However, much greater growth suppression is achieved by combinatorial inhibition with the epidermal growth factor receptor (EGFR) kinase inhibitor erlotinib. Together, these results validate the hHGFtg-SCID mouse model for in vivo determination of MET sensitivity to drug inhibition. Our findings also indicate that simultaneously targeting the MET and EGFR pathways can provide synergistic inhibitory effects for the treatment of cancers in which both pathways are activated. Cancer Res; 70(17); 6880–90. ©2010 AACR.
Chronic Viral Infections and Invasive Procedures: Risk of Vertical Transmission and Current Recommendations
Authors: López Marta , Coll Oriol
Published: July 2010

The risk of transmission of human immunodeficiency virus (HIV), hepatitis B (HBV) and hepatitis C virus (HCV) during invasive procedures may not be negligible, although it has been poorly assessed. The risk of hepatitis B transmission during amniocentesis seems to be low, but it may be increased in women with a positive HBeAg. HCV transmission risk cannot be established because evidence is lacking. No information exists about other invasive procedures in such infections. An increased risk of vertical transmission following an invasive procedure was suggested in HIV infection, but amniocentesis seems to be safe when performed under highly active antiretroviral treatment, with a low viral load and when avoiding placental passage. International guidelines do not clearly define policies to screen for maternal blood-borne virus infection during invasive procedures. Nevertheless, serological status should be assessed in all cases and parents should be aware of the existing evidence for transmission risk. Transplacental amniocentesis should always be avoided.
Prenatal Sonographic Diagnosis of Duplicated Middle Cerebral Artery
Authors: Ventura Walter , Nazario Conny , Ingar Jaime , Huertas Erasmo , Limay Antonio , Castillo Walter
Published: July 2010

We report a fetus scanned by color Doppler ultrasound at 37 weeks for suspicion of growth restriction with an extremely rare variation of duplicated middle cerebral artery. Three-dimensional color power Doppler and tomographic ultrasound imaging enhanced our incidental finding.