bluuebunny/crossref_metadata_2025 huggingface dataset:
MOLECULAR EVOLUTION OF GPCRS: GLP1/GLP1 receptors
Authors: Hwang Jong-Ik , Yun Seongsik , Moon Mi Jin , Park Cho Rong , Seong Jae Young
Published: March 2014

Glucagon-like peptide 1 (GLP1) is an intestinal incretin that regulates glucose homeostasis through stimulation of insulin secretion from pancreatic β-cells and inhibits appetite by acting on the brain. Thus, it is a promising therapeutic agent for the treatment of type 2 diabetes mellitus and obesity. Studies using synteny and reconstructed ancestral chromosomes suggest that families for GLP1 and its receptor (GLP1R) have emerged through two rounds (2R) of whole genome duplication and local gene duplications before and after 2R. Exon duplications have also contributed to the expansion of the peptide family members. Specific changes in the amino acid sequence following exon/gene/genome duplications have established distinct yet related peptide and receptor families. These specific changes also confer selective interactions between GLP1 and GLP1R. In this review, we present a possible macro (genome level)- and micro (gene/exon level)-evolution mechanisms of GLP1 and GLP1R, which allows them to acquire selective interactions between this ligand–receptor pair. This information may provide critical insight for the development of potent therapeutic agents targeting GLP1R.
Recanalization after acute deep vein thrombosis
Authors: Brandao Gustavo Mucoucah Sampaio , Sobreira Marcone Lima , Rollo Hamilton Almeida
Published: March 2014

The process of recanalization of the veins of the lower limbs after an episode of acute deep venous thrombosis is part of the natural evolution of the remodeling of the venous thrombus in patients on anticoagulation with heparin and vitamin K inhibitors. This remodeling involves the complex process of adhesion of thrombus to the wall of the vein, the inflammatory response of the vessel wall leading to organization and subsequent contraction of the thrombus, neovascularization and spontaneous lysis of areas within the thrombus. The occurrence of spontaneous arterial flow in recanalized thrombosed veins has been described as secondary to neovascularization and is characterized by the development of flow patterns characteristic of arteriovenous fistulae that can be identified by color duplex scanning. In this review, we discuss some controversial aspects of the natural history of deep vein thrombosis to provide a better understanding of its course and its impact on venous disease.
Gender-related differences in critical limb ischemia due to peripheral arterial occlusive disease
Authors: Santos Vanessa Prado dos , Alves Carlos Alberto Silveira , Lopes Cicero Fidelis , Araujo Filho Jose Siqueira de
Published: March 2014

BACKGROUND: Mortality from cardiovascular disease has declined among men and increased among North American women. Recent studies have revealed differences between genders in the epidemiology of atherosclerotic disease. OBJECTIVE: To study possible differences between male and female patients with critical limb ischemia (CLI) according to risk factors of atherosclerosis and clinical characteristics of lower limbs with peripheral arterial occlusive disease (PAOD). METHODS: The study included 171 male and female patients treated for CLI due to infrainguinal PAOD and compared clinical characteristics (Rutherford category and PAOD territory), risk factors for atherosclerosis (diabetes, age, smoking and hypertension) and number of opacified arteries on digital angiograms of the leg. The EPI-INFO software was used for statistical analysis, and the level of significance was set at p<0.05. RESULTS: Mean age was 70 years, and 88 patients were men (52%). For most patients (both genders), Rutherford category was 5 (82 % of men and 70% of women; p=0.16). The group of women had higher mean age (73 vs. 67 years; p=0.0002) and greater prevalence of diabetes (66% vs. 45%; p=0.003) and hypertension (90% vs. 56%; p=0.0000001). Among men, the prevalence of smoking was higher (76% vs. 53%; p=0.0008). The analysis of digital angiograms revealed that opacification of only one artery in the leg was found for 74% of women (vs. 50% of men). CONCLUSION: The prevalence of risk factors for atherosclerosis and the characteristics of PAOD are different between male and female patients with CLI.
Applications for Oncologic Drugs: A Descriptive Analysis of the Oncologic Drugs Advisory Committee Reviews
Authors: Chan John K. , Kiet Tuyen K. , Monk Bradley J. , Young-Lin Nichole , Blansit Kevin , Kapp Daniel S. , Amanam Idoroenyi
Published: March 2014

Background

Despite advances in cancer research, the majority of drug applications submitted to the U.S. Food and Drug Administration (FDA) are not approved. It is important to identify the concerns of the Oncologic Drugs Advisory Committee (ODAC) from rejected applications.

Methods

All applications referred to the ODAC from 2001 to 2012 were reviewed.

Results

Of 46 applications, 31 (67%) were for full and 15 (33%) were for supplemental approval, 34 (74%) were for solid and 12 (26%) were for hematologic tumors. In all, 22 (48%) were not approved. ODAC comments addressed missing or inadequate data (65%), excessive toxicity (55%), inappropriate study endpoints (45%), poor study design (40%), and insufficient sample size (30%). To define efficacy, 19 applications used response rates (RR) (median = 38%), and 19 applications used hazard ratios (HR) (median = 0.67). For all organ systems combined, the median cumulative grade 3 or 4 toxicity was 64%. Drugs with higher RR, lower HR, and lower toxicity were more likely to be approved versus other drugs (89% vs. 45%; p = .02). Over time (2001–2004, 2005–2008, 2009–2012), there was an increase in the following: number of applications submitted for review (from 11 to 12 to 23, respectively), number of approvals (from 6 to 6 to 12, respectively), and proportion of trials using progression-free survival as a primary endpoint (from 0% to 50% to 70%, respectively; p = .01).

Conclusion.

Of all applications, common ODAC concerns included inadequate data, excessive toxicity, and inappropriate study endpoints. Over time, there was an approximate doubling of FDA application submissions and approved oncology drugs.
Glucagon-Like Peptide 1 Attenuates the Acceleration of Gastric Emptying Induced by Hypoglycemia in Healthy Subjects
Authors: Plummer Mark P. , Jones Karen L. , Annink Chris E. , Cousins Caroline E. , Meier Juris J. , Chapman Marianne J. , Horowitz Michael , Deane Adam M.
Published: March 2014

OBJECTIVE

Exogenous GLP-1 slows gastric emptying in health and diabetes leading to diminished glycemic excursions. Gastric emptying is markedly accelerated by hypoglycemia. The primary objective was to determine whether GLP-1 attenuates the acceleration of gastric emptying induced by hypoglycemia.

RESEARCH DESIGN AND METHODS

Ten healthy volunteers were studied on four separate days in a randomized double-blind fashion. Blood glucose was stabilized using a glucose/insulin clamp at hypoglycemia (2.6 mmol/L on two occasions [hypo]) or euglycemia (6.0 mmol/L on two occasions [eu]) between T = −15 and 45 min before clamping at 6.0 mmol/L until 180 min. During hypoglycemia and euglycemia, subjects received intravenous GLP-1 (1.2 pmol/kg/min) or placebo. At T = 0 min, subjects ingested 100 g beef mince labeled with 20 MBq 99mTc-sulfur-colloid and 3 g of 3-O-methyl-glucose (3-OMG), a marker of glucose absorption. Gastric emptying was measured scintigraphically from T = 0 to 180 min and serum 3-OMG taken at 15-min intervals. The areas under the curve for gastric emptying and 3-OMG concentration were analyzed using one-way repeated-measures ANOVA with Bonferroni-Holm adjusted post hoc tests.

RESULTS

Gastric emptying was accelerated during hypoglycemia (hypo/placebo vs. eu/placebo; P < 0.001), as was glucose absorption (P < 0.03). GLP-1 slowed emptying during euglycemia (eu/placebo vs. eu/GLP-1; P < 0.001). However, hypoglycemia-induced acceleration of gastric emptying on placebo was markedly diminished by GLP-1 (hypo/placebo vs. hypo/GLP-1; P < 0.008), as was glucose absorption (P < 0.01).

CONCLUSIONS

Acute administration of exogenous GLP-1 attenuates, but does not abolish, the acceleration of gastric emptying by insulin-induced hypoglycemia in healthy subjects.
Structure and Frictional Properties of Colloid Gel
Authors: Tokita Masayuki
Published: March 2014

Polymer gels are known to be opaque when the preparation conditions, such as the reaction temperature and the composition, are changed. The increase of the opaqueness of the gel suggests strongly the change of network structure. Here, we are going to review the recent studies on the structure and the frictional study of the opaque poly(acrylamide) gel. The results indicate that the opaque poly(acrylamide) gel consists of the fractal aggregate of the colloidal particles of sub-micrometer in size. The density of the colloid particle is calculated from the structural parameters and is found to be of the order of about 1 g/cm3. The results indicate that the main chain component and the cross-linker is densely cross-linked into the particle. The frictional property of poly(acrylamide) gel is analyzed in terms of the structural parameters of the gel. It is found that the frictional property of the opaque gel is well explained in terms of the structural parameters of the opaque gel.
Electrical Characterization of Photodetectors Based on Poly(3-hexylthiophene-2,5-diyl) Layers
Authors: Ferrer Juan , Alonso José , De Ávila Susana
Published: March 2014

This paper presents the electrical characteristics of solution-processed organic photodetectors based on poly(3-hexylthiophene-2,5-diyl) semiconducting polymer layers deposited by spin-coating on interdigitated metal electrodes. Four different electrode shapes have been used for this study in order to appraise the optimum electrode geometry. The measurement of the resistance as a function of the temperature reveals a transition from negative to positive temperature coefficient material around 80 °C for the polymer layers. Besides, slow reversible changes in the photodetectors conductivity were observed when moved from vacuum to the air and under illumination with a xenon lamp, which can be explained by the formation of charge transfer complexes with molecular oxygen and the polymer. The photogenerated current-light power ratio was found to be approximately linear in the 200 to 550 mW/cm2 range.
Khmer decorative lintels and the allocation of artistic labour
Authors: Polkinghorne Martin
Published: March 2014

De l'établissement de modestes sanctuaires de village à ceux de colossaux monuments d'état, l'entreprise d'édification des temples d'Angkor a exigé une grande variété de spécialistes. Peu d'études ont suffisamment considéré ces structures du point de vue des hommes qui les ont construites - les artisans et artistes presque tous anonymes qui ont érigé les structures et taillé les bas-reliefs et l'ornementation architecturale. L'épigraphie ne peut nous fournir que de rares informations et, jusqu'à présent, peu de données archéologiques nous permettent de savoir comment était l'organisation de ces groupes. En considérant les différences et les similitudes dans les linteaux décoratifs, qui sont parmi les objets les plus répandus de la sculpture Khmer, cet article propose une explication de l'organisation du processus d'ornementation des temples à travers les sites de construction et des modes d'utilisation des gabarits souples par les artistes Khmer.
Tissue-Specific Microvascular Endothelial Cells Show Distinct Capacity To Activate NK Cells: Implications for the Pathophysiology of Granulomatosis with Polyangiitis
Authors: Tognarelli Sara , Gayet Julie , Lambert Marion , Dupuy Stéphanie , Karras Alexandre , Cohen Pascal , Guillevin Loïc , de Menthon Mathilde , Caillat-Zucman Sophie
Published: March 2014

The relevance of tissue specificity of microvascular endothelial cells (MECs) in the response to inflammatory stimuli and sensitivity to immune cell–mediated injury is not well defined. We hypothesized that such MEC characteristics might shape their interaction with NK cells through the use of different adhesion molecules and NK cell receptor ligands or the release of different soluble factors and render them more or less vulnerable to NK cell injury during autoimmune vasculitis, such as granulomatosis with polyangiitis (GPA). To generate a comprehensive expression profile of human MECs of renal, lung, and dermal tissue origin, we characterized, in detail, their response to inflammatory cytokines and to proteinase 3, a major autoantigen in GPA, and analyzed the effects on NK cell activation. In this study, we show that renal MECs were more susceptible than lung and dermal MECs to the effect of inflammatory signals, showing upregulation of ICAM-1 and VCAM-1 on their surface, as well as release of CCL2, soluble fractalkine, and soluble VCAM-1. Proteinase 3–stimulated renal and lung MECs triggered CD107a degranulation in control NK cell. Notably, NK cells from GPA patients expressed markers of recent in vivo activation (CD69, CD107a), degranulated more efficiently than did control NK cells in the presence of renal MECs, and induced direct killing of renal MECs in vitro. These results suggest that, upon inflammatory conditions in GPA, renal MECs may contribute to the recruitment and activation of NK cells in the target vessel wall, which may participate in the necrotizing vasculitis of the kidney during this disease.
The action homomorphism, quasimorphisms and moment maps on the space of compatible almost complex structures
Authors: Shelukhin Egor
Published: March 2014

We extend the definition of Weinstein’s action homomorphism to Hamiltonian actions with equivariant moment maps of (possibly infinite-dimensional) Lie groups on symplectic manifolds, and show that under conditions including a uniform bound on the symplectic areas of geodesic triangles the resulting homomorphism extends to a quasimorphism on the universal cover of the group. We apply these principles to finite-dimensional Hermitian Lie groups like the linear symplectic group, reinterpreting the Guichardet–Wigner quasimorphisms, and to the infinite-dimensional groups of Hamiltonian diffeomorphisms of closed symplectic manifolds that act on the space of compatible almost complex structures with an equivariant moment map given by the theory of Donaldson and Fujiki. We show that the quasimorphism on the universal cover of the Hamiltonian group obtained in the second case is symplectically conjugation-invariant and compute its restrictions to the fundamental group via a homomorphism introduced by Lalonde–McDuff–Polterovich, answering a question of Polterovich; to the subgroup of Hamiltonian biholomorphisms via the Futaki invariant; and to subgroups of diffeomorphisms supported in an embedded ball via the Barge–Ghys average Maslov quasimorphism, the Calabi homomorphism and the average Hermitian scalar curvature. We show that when the first Chern class vanishes this quasimorphism is proportional to a quasimorphism of Entov and when the symplectic manifold is monotone, it is proportional to a quasimorphism due to Py. As an application we show that a Sobolev distance on the universal cover of the Hamiltonian group is unbounded, similarly to the results of Eliashberg–Ratiu.
Yes, There is no Crisis
Authors: Braidotti Rosi
Published: March 2014

There is widespread consensus in the Humanities scholarly community that it is inappropriate to speak of a “crisis” of our field, yet we do spend a disproportionate amount of time actually justifying or defending our existence to the public. I want to argue that this is a constitutive contradiction of the Humanities today and that it reflects not only public concern about our relevance, but also significant internal fractures within the Humanities. In this paper, I want to look more closely at some of these inner fractures. I will argue that the Humanities can and will survive their present predicament and contradictions to the extent that they will show the ability and willingness to undergo a major process of transformation in response to both technological advances and geo-political developments.
Risk Evaluation and Mitigation Strategies: A Focus on the Mycophenolic Acid Preparations
Authors: Rostas Sara , Kim Miae , Gabardi Steven
Published: March 2014

Objective

To review risks associated with mycophenolic acid (MPA) preparations and evaluate their required risk evaluation and mitigation strategies (REMS) elements.

Data Sources and Extraction

Articles were identified through a non–date-limited MEDLINE and EMBASE search using the terms fetal toxicity, teratogenicity, risk evaluation and mitigation strategies, REMS, MPA, mycophenolate mofetil, enteric-coated MPA, and organ transplant. Information from the Food and Drug Administration (FDA) and the manufacturers of the MPA preparations was also evaluated.

Data Synthesis

The MPA preparations are associated with several potential risks, including gastrointestinal disturbances and myelosuppression; however, their impact on the fetus in pregnant patients taking 1 of these agents poses the greatest risk. The FDA approved REMS programs for all MPA products, both innovator and generic preparations, in September 2012. With evidence of increased risk of miscarriage and birth defects associated with MPA use, the FDA instituted a REMS program that contains both a medication guide and elements to assure safe use (ETASU).

Conclusion

The medication guides for the MPA products, which were previously FDA approved, should continue to be distributed to patients who get either an initial prescription filled or a refill. The ETASU requires prescribers to complete training and obtain patient signatures on the Patient-Prescriber Acknowledgment Form. A single, national, voluntary pregnancy registry specific to this medication has been established, and pregnant patients should be encouraged to participate. Although the impact of the MPA REMS on clinical practice is not clear, it is a step toward increasing the understanding of fetal risks with MPA.
In-laboratory sensitivity calibration of an optical emission spectroscopy system in vacuum ultraviolet wavelength range
Authors: Soma Shuntaro , Kurihara Kazuaki , Sasaki Koichi
Published: March 2014

We calibrated the wavelength dependence of the relative sensitivity of an optical emission spectroscopy system, which was composed of a grating monochromator and a secondary electron multiplier tube, in a vacuum ultraviolet wavelength range on the basis of the calibrated sensitivity of a silicon photodiode. The experimental result shows a significant wavelength dependence of the sensitivity in a wavelength range between 80 and 160 nm. The calibration curve was compared with the absolute sensitivity evaluated using a branching ratio technique at the Lyman and Balmer lines of atomic hydrogen.
A wide dynamic range CMOS image sensor with 200–1100 nm spectral sensitivity and high robustness to UV right exposure
Authors: Nasuno Satoshi , Kawada Shun , Koda Yasumasa , Nakazawa Taiki , Hanzawa Katsuhiko , Kuroda Rihito , Sugawa Shigetoshi
Published: March 2014

A highly UV-light sensitive and sensitivity robust CMOS image sensor with a wide dynamic range (DR) was developed and evaluated. The developed CMOS image sensor includes a lateral overflow integration capacitor in each pixel in order to achieve a high sensitivity and a wide DR simultaneously. As in-pixel photodiodes (PDs), buried pinned PDs were formed on flattened Si surface. The PD has a thin surface p+ layer with a steep dopant concentration profile to form an electric field that drifts photoelectrons to the pinned n layer. This structure improves UV-light sensitivity and its stability. In addition, a buried channel source follower driver was introduced to achieve a low pixel noise. This CMOS image sensor was fabricated by a 0.18-µm 1-polycrystalline silicon 3-metal CMOS process technology with buried pinned PD. The fabricated image sensor has a high sensitivity for 200–1100 nm light wave band, high robustness of sensitivity and dark current toward UV-light exposure and a wide DR of 97 dB. In this paper, the PD structures, the circuit, the operation sequence and the measurement results of this CMOS image sensor are discussed.
Schottky barrier height modification of metal/4H-SiC contact using ultrathin TiO2 insertion method
Authors: Tsui Bing-Yue , Cheng Jung-Chien , Lee Lurng-Shehng , Lee Chwan-Ying , Tsai Ming-Jinn
Published: March 2014

The fabrication processes, electrical characteristics, and reliability of the Schottky barrier diodes (SBDs) on an n-type 4H-silicon carbide (SiC) substrate are investigated. To modulate the Schottky barrier height (SBH), titanium dioxide (TiO2) is inserted at the interface between the metal and the SiC substrate. Ni, Mo, Ti, and Al are chosen to form SBDs. The maximum SBH modulation of 0.3 eV is obtained with a 5-nm-thick TiO2 layer. The SBH pinning factors of the SBDs without TiO2 insertion and with 2-nm-thick TiO2 insertion are similar. Therefore, the mechanism of the SBH modulation is attributed to the interface dipole-induced potential drop. Finally, the reliability of the SBD with TiO2 insertion is evaluated. The SBH, ideality factor, and reverse leakage current are stable after high forward current stress at 300 A/cm2 for 15000 s. This work provides a simple method to modulate the SBH on SiC and is feasible for SBD application.
Short Pulse Response of Ultrasonic Transducer Mode of Piezoelectric Copolymer Films of Vinylidene Fluoride-Trifluoroethylene
Authors: Sato Takashi , Koyama Kiyohito , Ikeda Susumu , Wada Yasaku
Published: March 2014

Ultrasonic transducers of vinylidene fluoride (VDF)-trifluoroethylene (TrFE) copolymer (acoustic impedance Z=4.3×106 kg/m2sec) were studied both theoretically and experimentally. The equivalent circuit by Mason was used for theoretical calculation of impulse response and conversion loss in the thickness mode with a backing load. The mechanical loss of the copolymer was taken into account in the calculation. Short pulse characteristics and high sensitivity were obtained for the transducer system with an aluminum backing load (Z=16.9×106 kg/m2sec) as predicted by calculation.
Dependence of Load Capacitance for a Coupling Quartz Crystal Resonator
Authors: Kawashima Hirofumi
Published: March 2014

This paper describes the dependence of load capacitance for a coupling quartz crystal resonator, in particular, a GT cut quartz crystal resonator. The coupling resonator causes a frequency variation by a change of coupling between each vibration. In this paper, it has been theoretically analyzed how the frequency characteristics vary when the coupling intensity is changed, and the results are compared with the experimental values. The coupling intensity between both vibrations is practically performed by the load capacitance CL. This influences frequency temperature characteristics, when discussing ±± ppm in frequency deviation over a wide temperature range of -30°C to +70°C.
Theoretical Considerations on Acoustic Field Formed by Fresnel-Zone-Type Focusing Radiator
Authors: Yamada Ken , Sugiyama Toshiki , Shimizu Hiroshi
Published: March 2014

Focusing performance of Fresnel-zone-type ultrasonic focusing systems is evaluated by calculating field distributions for an equivalent radiator composed of concentric annular-transducer elements, and is compared with that of a concave radiator. It is demonstrated that the Fresnel-zone-type radiator presents almost the same focused field as the corresponding concave one and gives reduced sidelobes uner the existence of propagation loss. Focusing characteristics of radiators with inactivated transducer elements in the central part are also examined.
An Airborne Ultrasound Echo Analysis of a Polyhedron
Authors: Tabei Makoto , Sato Mitsunobu , Ueda Mitsuhiro
Published: March 2014

This paper describes a systematic procedure to calculate the echo signal from a polyhedron of arbitrary shape. The echo is defined as the integration over the surface of the object. We assume that in the case of a convex object, the echo from each facet contributes independently to the total echo signal. Numerical evaluation of the integration is performed by an exponent integral scheme and shows good agreement with the experiments.
A Numerical Transient Analysis for Acoustic Field Including Reflective Boundary by using PSW Method
Authors: Watanabe Yuji , Shibayama Kimio
Published: March 2014

For applications of ultrasonic technique such as imaging and fish detection, it is important to estimate the paths of propagation of received waves since the direct wave and reflected or refracted waves must be separated to pick out desired information from the received signal. However, most conventional methods have not analysed this problem sufficiently. Therefore, the authors have developed a new method called “propagation of separated wavefront” (PSW). In this paper we apply this method to transient analysis of a reflective sound field.
Fundamental Considerations of Excitation of a Flexural Progressive Wave and its Application
Authors: Tomikawa Yoshiro , Kondo Tetsuya , Ogasawara Toshiharu , Sugawara Sumio , Konno Masashi
Published: March 2014

This paper deals with fundamental considerations of excitation of a flexural progressive wave and its application to an ultrasonic motor. The conditions for excitation of a progressive wave not only in a straight line flexurally vibrating medium, but also in a flexural disk vibrator are made clear, and conditions of the excitation method for an ultrasonic motor are reported to be very similar to those for an electro-magnetic induction motor. Characteristics of a disk vibrator for an ultrasonic motor and results of fundamental experiments on it are also described.
Surface Transformations in Glass Initiated by Laser-Driven Shock
Authors: Kanemitsu Yoshihiko , Tanaka Yuichi , Harada Yoshinao
Published: March 2014

Long-range and delayed structural changes in glass surfaces were observed using high-power laser pulses. Under laser excitation, intense shock waves propagated hemispherically into the glass. Structural changes extended many millimeters beyond the area of the localized laser damage. The cracks were formed spirally around the localized damage site. These changes were clearly observed at 12 h after the laser irradiation. Long-range and delayed changes are caused by a chemical reaction under stress around cracks induced by laser-driven shock. It is also pointed out that laser-driven shock causes crystallization in a-Si.
Photoacoustic Images by Rapid Scanning Method
Authors: Izuchi Masaya , Nakano Hidetoshi , Nagai Satoshi
Published: March 2014

A photoacoustic (PA) imaging system for fast acquisition of two-dimensional data is described. The PA signal is generated not by modulation of the intensity of a laser beam but by rapid scanning of the beam with a fixed intensity. PA images can be reproduced by passing the microphone signal through a frequency filter, the character of which is discussed. It takes only a minute or less to obtain an image of 128×124 pixels, which is similar to that by the normal PA imaging technique.
Apparatus for Measurement of Complex Shear Modulus of Liquid Crystals at Low Frequencies
Authors: Yamamoto Jun , Nakamura Haruki , Okano Koji
Published: March 2014

An apparatus for measuring the frequency dependence of the complex shear modulus of liquid crystals as low as 102 dyn/cm2 at low frequencies (from 1 Hz to 1 kHz) was constructed, and was applied to the nematic and smectic A phase of 40.8 (butoxybenziliden-octylanine). The shear viscosity of unoriented multidomain sample in the smectic A phase showed a divergent behavior of 1/ω when the frequency went to zero. This anormalous behavior was interpreted in terms of the anharmonic effects associated with the thermal undulation of the smectic layers based on the theory of Mazenko, Ramaswamy and Toner.
Ultrasonic Attenuation in Liquid 3He–4He Solutions
Authors: Iwasa Izumi , Fujii Itsuhiro , Ikushima Akira J.
Published: March 2014

Temperature dependences of ultrasonic attenuation are measured in liquid 3He–4He solutions with 3He concentrations x
3 of 1.3, 2.9 and 5.0% under the saturated vapor pressure at sound frequencies of 10,30 and 50 MHz and at temperatures between 0.5 and 2 K. A maximum of attenuation is observed at each concentration and frequency. At the maximum temperature 2ωτ=1, where ω/2π is the sound frquency and τ the relaxation time of thermal phonons, and the relaxation time due to phonon-3He scattering is determined to be 3×10-11/T5
x
3.
Ultrasonic Study on Sintered Silver Powders at Low Temperatures
Authors: Iwasa Deng , Ikushima Akira J.
Published: March 2014

Sound attenuation and velocity in sintered silver powders with and without liquid 4He and those with solid 4He have been measured by using a phase-sentitive ultrasonic system. When the sample was immersed in liquid 4He, the sound attenuation increased sharply at 4.2 K, kept a constant level with lowering temperature, and then decreased gradually below T
λ. On the other hand, in the sample without liquid 4He, the attenuation was almost independent of temperature. The velocity in the sample with liquid 4He was about 0.28% smaller than that without liquid 4He at 4.2 K. Below the surperfluid transition temperature the velocity gradually increased up to a constant value.
Study of Elastic Properties of Frog Striated Muscle by Scanning Laser Acoustic Microscopy
Authors: Kato Satoru , Hatta Ichiro
Published: March 2014

A scanning laser acoustic microscope (SLAM) is a powerful tool for precise measurement of local elasticity. In the case of biological materials, including muscle, the ultrasound velocity can be determined within an accuracy of ±3 m/s because it is close to that in water. Analysis of the SLAM interferometric image from a muscle with and without stimulation was made using a newly designed image processing system. The system is capable of tracing the stimulation-induced change in the sound velocity of a muscle with a time resolution of 33 msec.
High-Resolution Long-Wavelength Holographic Imaging with the Aid of Prediction Theory –An Application of AR Model to Multifrequency Hologram–
Authors: Miyashita Toyokatsu
Published: March 2014

This paper presents an application of the AR model in the scheme of the maximum entropy theory to a multifrequency hologram-matrix of a few frequency elements in order to get reconstructed images of higher resolution and quality. A direct extrapolation of the frequency aperture of the hologram-matrix by the AR model is shown to be effective and stable almost independent of the order of the model.
Bistability of Electro-Optic Effects in Ferroelectric Liquid Crystals
Authors: Ozaki Masanori , Kishio Shin-ichi , Yoshino Katsumi , Mikami Naoko , Higuchi Ryo-ichi , Sakurai Takao
Published: March 2014

New type of bistable electro optic effects utilizing the transition between winding and unwinding states of helicoidal structure of the ferroelectric chiral smectic liquid crystals with large spontaneous polarization are studied. One effect uses the anomalous voltage-transmission hysteresis, and another effect uses the anomalous temperature-transmission hysteresis due to the balance between the forces of the chirality and the wall effect. In these effects the fast switching response is realized, and the special surface treatment and the optical polarizers are not required.
Crystal Growth of PbHPO4 by Gel Method and Its Ferroelectric Properties
Authors: Nakatani Noriyuki
Published: March 2014

Single crystals of PbHPO4 were grown by the chemical reaction of H3PO4 and Pb(NO3)2 in test tubes by a simple gel method. We used tetramethoxysilane as the gel forming agent. Temperature dependence of dielectric constant and of spontaneous polarization, and hysteresis loop of specimens prepared from these crystals were examined. The crystals were proved to be biased in both directions almost equally by internal field. The bias field is induced by keeping the crystal in the ferroelectric phase, and the bias is reduced by heat treatment as well as by the application of a.c. field.
Preparation of (Pb, La)TiO3–PbTiO3 Thin Films with Superlattice Structure
Authors: Adachi Hideaki , Mitsuyu Tsuneo , Yamazaki Osamu , Wasa Kiyotaka
Published: March 2014

(Pb, La)TiO3–PbTiO3 thin films with superlattice structure have been successfully grown on sapphire substrates. Each layer of epitaxial perovskite structure was alternately deposited by computer-controlled multi-target co-sputtering system. The minimum modulation wavelength was about 100 A and interdiffusion significantly occurred when thickness of periodic layer was less than 100 A.
Measurement of Stress Induced Birefringence of Bi12GeO20 Single Crystals by a New Ellipsometry
Authors: Mikami Noboru , Nagao Chie , Sawada Takao , Sato Ken
Published: March 2014

Optical qualities of Bi12GeO20 single crystals with facets are determined. A facet has higher absorbance and larger refractive index by 3×10-4 than those of off facet. Stress induced birefringence and extinction ratio are examined by a new ellipsometry for evaluating an optical active birefringent medium. Birefringence exists around {110} facet, the maximum retardation reaches 4 degrees per 1 mm thickness. Light is scatterd at the {110} facet boundary, and extinction ratio reaches -35 dB at the maximum point. On the contrary, the extinction ratio inside the facet and off-facet region is under -45 dB.
Effects of the Adhesive Layer on a Composite-Bar Resonator
Authors: Sasaki Yukihiko , Takeuchi Yoshio , Marutake Masakazu
Published: March 2014

Elastic compliance constants were measured of several kinds of adhesive layers in a quartz-quartz composite-bar resonator by using a proposed equation. By taking the constants of the adhesive layer into consideration, the elastic compliance constants of some crystals were obtained. For many kinds of high-polymer adhesives, this correction was found necessary for obtaining elastic compliance constants at higher temperatures. Further by using the same equation, the density of the adhesive layers was obtained.
Liquid Phase Sintering of Mixed-Sintering Ceramics Using Pb(Li1/4Fe1/4W1/2)03
Authors: Sakata Koichiro , Takahara Hideyuki
Published: March 2014

Low temperature-sintering of mixed-sintering ceramics was investigated using lead lithium-iron tungstate (Pb(Li1/4Fe1/4W1/2)O3; PLFW). The addition of 5 wt% PLFW was effective for lowering the sintering temperature from 1,000 to 920°C, while retaining a high dielectric constant (ε>10,000 at 20°C). Moreover, the PLFW made it possible to improve dielectric properties; the resistivity at 20°C from 1011 to 1013 Ω·cm, and the dielectric loss at 100°C from 3 to 0.6%.
Vibration Analysis of Coupled Flexural Torsional Mode Tuning Fork Type Quartz Crystal Resonator–Part (3)–
Authors: Kawashima Hirofumi
Published: March 2014

This paper describes the frequency temperature characteristics, resonant frequencies, and electrical equivalent circuit constants of a coupled flexural torsional mode tuning fork type quartz crystal resonator which vibrates at the second overtone for flexure and the fundamental vibratinon for torsion. In addition, the object of this paper is, theoretically, to clarify how resonant frequencies and frequency temperature coefficients vary when thickness or a normalized frequency is changed. This resonator changes less than 10 ppm in frequency deviation over a wide temperature range of -20°C to +60°C.
Radiation-Induced Frequency Changes in Quartz Oscillators
Authors: Shimoda Yoshio , Uno Takehiko
Published: March 2014

Radiation effects on quartz oscillators and quartz resonator units fabricated from unswept supreme Q quartz have been evaluated. The changes in oscillator frequency caused by gamma rays are within 5 ppm. They originate from changes in resonator frequency. The effects of other components are negligible. Infrared absorption spectra of irradiated quartz blanks demonstrate a strong relation between resonator frequency changes and defect concentration in quartz. There is little difference between gamma ray and electron irradiation if the electrons have enough energy to penetrate the quartz blank.
A Method for Suppressing the Unwanted Signal Due to the L(0, 2) Mode in an L(0, 3) Mode Pulse Compression Filter by Means of a Tapered Cylindrical Fused Quartz Rod
Authors: Yoshizawa Masasumi , Kiryu Syogo , Moriya Tadashi , Fuse Tadashi
Published: March 2014

In an attempt to improve a pulse compression filter using a fused quartz rod, we devised a method to eliminate an unwanted L(0, 2) signal over a wide frequency range and, at the same time, obtain sufficient time dispersion. We found that the suppression of the L(0, 2) unwanted signal is realized using the freouency band where the change of patterns of L(0, 2) and L(0, 3) modes is slight. Sufficient time dispersion is obtained using a tapered cylindrical fused quartz rod.
Measurement of Frequency Characteristics of Ultrasound Attenuation (FCA) of Phantoms by T–R Technique
Authors: Soetanto Kawan , Tanaka Motonao , Ohtsuki Shigeo , Okujima Motoyoshi
Published: March 2014

The frequency characteristics of ultrasonic attenuation (FCA) of scar tissue, protein fiber tissue, cotton thread tissue, and vegetable fiber tissue (luffa specimens) were measured by T–R technique.1) The FAC of the specimens used in this study is changed linearly with frequency except for those of the luffa specimens. It was found that the diameter of the single luffa fiber affects the frequency characteristics of ultrasonic attenuation.
Construction of Ultrasonic Motors and their Application
Authors: Tomikawa Yoshiro , Ogasawara Toshiharu , Sugawara Sumio , Konno Masashi , Takano Takehiro
Published: March 2014

This paper deals with construction of an ultrasonic motor and their application; a paper-sending device using a flat rectangular type ultrasonic motor is described. Various types of ultrasonic motors can be constructed by considering displacement combinations in the horizontal and vertical directions at the elliptic motion yielded. As for this elliptic motion, multi-mode vibrators using degenerate modes of the same or different form are utilized.
Photoacoustic Determination of Photoinjection Efficiencies at the Interface in Double-Layered Organic Photoconductors
Authors: Kanemitsu Yoshihiko , Imamura Shunji
Published: March 2014

Photoinjection efficiencies of holes from the carrier generation layer into the carrier transport layer (CTL) in double-layered organic photoconductors were measured using a photoacoustic technique. Photoinjection efficiencies were derived by measuring the decrease in photoacoustic signal when an electric field was applied to the samples. The injection efficiency depends on the concentration of transporting molecule doped in the polymer of the CTL. The injection efficiency is limited by the low ability to transport holes from the interface into the CTL.
A Remote Measurement Method of Acoustic Velocity in Liquids by a Pair of Leaky Rayleigh Waveguides
Authors: Motegi Ryohei , Takeuchi Shin-ichi , Sato Toshio , Chubachi Noriyoshi
Published: March 2014

A pair of leaky Rayleigh waveguides is employed as acoustic probes to measure the acoustic velocity of liquids. In this method, one end of a long acoustic waveguide is immersed in a sample liquid, while the other end is not immersed in the liquid where a wedge transducer is fixed. Long steel plates have been investigated experimentally as Rayleigh waveguides to measure the acoustic velocity of water. The validity of this method was confirmed by the experiment.
Measurements of Non-Interacting Angle in the Scattering of Sound by Sound for Gases
Authors: Tsuchiya Takao , Watanabe Yoshiaki , Urabe Yasumasa
Published: March 2014

Non-interacting angle at which the nonlinear interaction between two crossing waves does not occur is investigated. In the time domain, a new approach to derive the non-interacting angle which depends on the nonlinearity parameter of medium is presented. The exact treatment of the angle-dependent parameter for the nonlinear interaction is carried out. To measure the non-interacting angle, the phase modulation of a probing wave of 40 kHz is observed. The experimental results for gaseous medium of air, freon, or argon show good agreement with the theoretical prediction.
Measurement of Vorticity Distribution Using Four Sets of Measuring Apparatus
Authors: Liu Maokai , Motooka Seiichi , Shino Masato , Okujima Motoyoshi
Published: March 2014

The authors devised a means of measuring the vorticity distribution using the reciprocal ultrasonic method. Vorticity measuring apparatus is arranged on four corners of a square in the vortex field and theoretical and experimental analysis of calculating vorticity distribution in the vortex with angular velocity gradient in the radial direction is described.
A Cascade Type Optical Algebraic Device Using Ultrasonic Diffraction Grating
Authors: Toda Kohji , Urabe Heijiro
Published: March 2014

A cascade type optical switching device for binary algebraic processing is described. The device consists of several interdigital transducers operating at a liquid-solid boundary. The ultrasound beams radiated into the liquid operate as acoustooptical gratings for optical switching. Combined with a charge coupled device as a photodetector array, the device contributes a binary number product. The operation principle and experimental confirmation for a four-bit binary number product are described.
Precise Measurement of Leaky SAW Velocity on LiTaO3-36° YX Substrates Using a Comb-Filter Method
Authors: Yuhara Akitsuna , Hirashima Tetsuya , Watanabe Hitoshi , Yamada Jun , Iwama Akira
Published: March 2014

A precise measurement method for SAW velocity using a comb-filter is presented. Some of the points in this method are proper numbering of the comb-peaks, verification of the numbering, a calculation formula for phase velocity and consideration of measurement accuracy. Using the method, leaky SAW velocity on LiTaO3-36° YX substrates with Al film is determined up to 1 GHz. The studies reveal the following: dispersion of the wave is linear in frequency and film thickness, and the measurement accuracy at 840 MHz is ±0.3 m/s (±0.7×10-4).
Ultrasonic Levitation and Accompanying Acoustic Streaming
Authors: Mitome Hideto
Published: March 2014

An equation to estimate requisite sound pressure level for ultrasonic levitation of a sample in the standing wave field has been formulated and shown to be in good agreement with experimental data. The requisite sound pressure depends not on the weight of a sample but on its density. The squared requisite sound pressure is proportional to the density of a sample and inversely proportional to the frequency of sound. Flow visualization experiments have shown that acoustic streaming is generated in the standing wave field in a cylinder when the sound pressure level is high.
Effect of Intense Aerial Ultrasonic on Electrostatic Precipitation
Authors: Nakane Tomoo , Seya Koichiro
Published: March 2014

This paper examines the effect of ultrasonic field on electrostatic precipitation. Diluted sub-micron particles were the only object of this experiment, and their collection efficiency increased using 22 kHz ultrasonic waves. Influence of ultrasonic on particle flow inside an electrostatic precipitator was also investigated.
A Sound Intensity Probe Using the Nonlinear Behaviors of Sound Wave
Authors: Tsuchiya Takao , Kimura Keigo , Watanabe Yoshiaki , Urabe Yasumasa
Published: March 2014

A sound intensity probe using the nonlinear behaviors of the sound wave is presented. The principle of the probe is theoretically discussed with regard to the variation and angular dependence of the phase velocity caused by the non-collinear interaction of sound waves. Two parametric receiving arrays whose probing waves propagate in opposite directions are applied to the sound intensity probe. The basic characteristics of the probe are observed, and the results support that the probe is applicable for the sound intensity measurements.
Computer Simulation of Measurement of Ultrasound Attenuation Coefficient by Broad Band Continuous-Echo Technique (Gamma Variate Method)
Authors: Hayakawa Yoshinori , Tada JunIchiro , Inada Tetsuo
Published: March 2014

Computer simulation experiments were made using the gamma variate method. The method is one proposed by the authors and uses a broad band interrogating wave. The interrogating wave was assumed to be delta function in time scale. Five random scatterers at distances of 90 and 100 mm from the transducer were assumed. An attenuation coefficient proportional to the frequency (0.01 Np/mm/MHz) was also assumed. Frequencies between 0.2 and 3.2 MHz were used for the analysis. The averaged spectrum of 300 simulation experiments gave 0.00996 Np/mm/MHz which was approximately equal to the assumed value.
A Photoacoustic Study of Light-Induced Degradation of Layered Organic Photoconductors
Authors: Kanemitsu Yoshihiko , Imamura Shunji
Published: March 2014

The influence of prolonged illumination on photocarrier generation in layered organic photoconductors was studied using photoacoustic spectroscopy. Prolonged light exposure under an applied electric field decreases the photoacoustic (PA) signal and increases the photocarrier generation efficiency. When the applied field is off, the PA signal reverts to the initial value very slowly. The increase in the photogeneration efficiency and the slow recovery of the PA signal are caused by space charge due to the trapping of photocarriers. The internal electric field due to space charge was evaluated using photoacoustic spectroscopy.
Improvement of Piezoelectric Photoacoustic Imaging Using Two Images at Different Modulation Frequencies
Authors: Nagata Yoshihiko , Ogiso Hisato , Yamanaka Kazushi , Koda Toshio
Published: March 2014

A new method is presented to improve piezoelectric photoacoustic imaging. This technique uses two images at different modulation frequencies to cancel the background caused by the coupling condition and the spatially nonuniform sensitivity of the piezoelectric sensor. It is found that the image of an object with sub-surface defects obtained by this technique is much clearer than a conventional image. The obtained photoacoustic image is compared with the ultrasonic image.
High Sensitivity, High Resolution Ultrasound Pulse-Echo Measurement Using Deconvolution Filtering
Authors: Yamada Akira
Published: March 2014

This paper presents a new deconvolution filtering technique for the realization of high sensitivity and high resolution ultrasonic pulse-echo measurement. The technique is based on two deconvolution filters: one with high resolution capability at the cost of large processing noise, and the other with small noise but low resolution capability. The smaller output of the two filters is ultimately taken, thereby achieving a compatibility between high resolution and low noise capability.
Frequency Dependence of Phonon Mean Free Path in Vitreous Silica
Authors: Ikari Hiroshi
Published: March 2014

The power dependence of the heat pulse profiles in vitreous silica (0.04 mm thickness) has been measured at 4 K. Around the critical power for film boiling, a new anomalous diffusive mode develops and its arrival time is markedly retarded with increasing power. The power dependence of the phonon mean free path has been estimated by fitting the new diffusive mode to the diffusion equation. The obtained mean free path shows remarkable decrease with increasing power and saturates at 26 Å. This minimum mean free path is approximately the same as typical correlation length in glasses estimated by Graebner et al.
Ultrasonic Spectroscopy for Teflon/Glass Bead Composite System
Authors: Hiramatsu Nobuyasu , Taki Seiji , Matsushige Kazumi
Published: March 2014

To investigate the frequency characteristics of ultrasonic waves transmitted through samples containing some foreign particles, ultrasonic Spectroscopy was carried out for Teflon/glass bead composite samples where bead sizes were varied from 850 µm to 25 µm. With the decrease of the bead size, the spectral amplitude first decreases over the whole frequency range, and the low frequency pattern recovers. The spectral amplitude takes minimum at a particular bead size depending on the frequency, and this minimum shifts to the small bead size side with the increase of frequency. Those behaviors are discussed with the theory of acoustic wave scattering.