bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiattribute Selection of Acute Stroke Imaging Software Platform for Extending the Time for Thrombolysis in Emergency Neurological Deficits (EXTEND) Clinical Trial
Authors: Churilov Leonid , Liu Daniel , Ma Henry , Christensen Soren , Nagakane Yoshinari , Campbell Bruce , Parsons Mark W. , Levi Christopher R. , Davis Stephen M. , Donnan Geoffrey A.
Published: July 2012

Background

The appropriateness of a software platform for rapid MRI assessment of the amount of salvageable brain tissue after stroke is critical for both the validity of the Extending the Time for Thrombolysis in Emergency Neurological Deficits (EXTEND) Clinical Trial of stroke thrombolysis beyond 4.5 hours and for stroke patient care outcomes.

Aims

The objective of this research is to develop and implement a methodology for selecting the acute stroke imaging software platform most appropriate for the setting of a multi-centre clinical trial.

Methods

A multi-disciplinary decision making panel formulated the set of preferentially independent evaluation attributes. Alternative Multi-Attribute Value Measurement methods were used to identify the best imaging software platform followed by sensitivity analysis to ensure the validity and robustness of the proposed solution.

Results

Four alternative imaging software platforms were identified. RApid processing of Perfusion and Diffusion (RAPID) software was selected as the most appropriate for the needs of the EXTEND trial. A theoretically grounded generic multi-attribute selection methodology for imaging software was developed and implemented.

Conclusions

The developed methodology assured both a high quality decision outcome and a rational and transparent decision process. This development contributes to stroke literature in the area of comprehensive evaluation of MRI clinical software. At the time of evaluation, RAPID software presented the most appropriate imaging software platform for use in the EXTEND clinical trial. The proposed multi-attribute imaging software evaluation methodology is based on sound theoretical foundations of multiple criteria decision analysis and can be successfully used for choosing the most appropriate imaging software while ensuring both robust decision process and outcomes.
Management reference points to account for direct and indirect impacts of fishing on marine mammals
Authors: Moore Jeffrey E.
Published: July 2012

Abstract

Reference points can help implement an ecosystem approach to fisheries management (EAF), by establishing precautionary removal limits for nontarget species and target species of ecological importance. PBR (Potential Biological Removal), developed under the U.S. Marine Mammal Protection Act (MMPA), is a limit for direct mortality for marine mammals, but it does not account for indirect effects of fishing due to prey depletion. I propose a generalization of PBR (called PBR*) to account for plausible changes in marine mammal carrying capacity (ΔK) from prey biomass decline relative to two example benchmarks: SSBMSY (maximum sustainable yield biomass for all known prey species) or SSBK (unfished prey biomass). PBR* can help identify when indirect fishing effects (alone, or combination with direct mortality estimates) may stymie MMPA objectives, and could inform catch limit estimates for target species that are also important as marine mammal prey. As a case study, I applied PBR* estimates to evaluate the possible combined direct + indirect effects of fishing on cetaceans in northeastern U.S. waters. Estimated distributions for ΔK were based on fish stock assessments and meta‐analysis of predator‐prey relationships from the mammalian literature. Based on this analysis, increased risk of marine mammal depletion due to indirect fishing effects was not evident, although this result must be interpreted cautiously given our limited understanding of cetacean diets and marine trophic dynamics. This study is intended to illustrate a possible practical approach for incorporating indirect fisheries impacts on marine mammals into a comprehensive management framework, and it raises several scientific and policy issues that merit further investigation.
UV/TiO2 Photocatalytic Degradation of Xanthene Dyes
Authors: Pereira Luciana , Pereira Raquel , Oliveira Catarina S. , Apostol Laura , Gavrilescu Mariana , Pons Marie‐Noëlle , Zahraa Orfan , Madalena Alves Maria
Published: July 2012

UV/titanium dioxide (TiO2) degradation of two xanthene dyes, erythrosine B (Ery) and eosin Y (Eos), was studied in a photocatalytic reactor. Photocatalysis was able to degrade 98% of Ery and 73% of Eos and led to 65% of chemical oxygen demand removal. Experiments in buffered solutions at different initial pH values reveal the pH dependence of the process, with better results obtained under acidic conditions due to the electrostatic attraction caused by the opposite charges of TiO2 (positive) and of anionic dyes (negative). Batch activity tests under methanogenic conditions showed the high toxicity exerted by the dyes even at low concentrations (~85% with initial concentration of 0.3 mmol L−1), but the end products of photocatalytic treatment were much less toxic toward methanogenic bacteria, as detoxification of 85 ± 5% for Eos and 64 ± 7% for Ery were obtained. In contrast, the dyes had no inhibitory effect on the biogenic‐carbon biodegradation activity of aerobic biomass, obtained by respirometry. The results demonstrate that photocatalysis combining UV/TiO2 as a pretreatment followed by an anaerobic biological process may be promising for the treatment of wastewaters produced by many industries.
Biodiversity, Governance, and the Allocation of International Aid for Conservation
Authors: Miller Daniel C. , Agrawal Arun , Roberts J. Timmons
Published: July 2012

There is little systematic knowledge about the magnitude and allocation of international funding flows to support biodiversity conservation in the developing world. Using the newly released AidData compilation, we present a comprehensive assessment of official donor assistance for biodiversity during 1980–2008. We find that biodiversity aid increased markedly in the early 1990s, but that estimates of current aid are likely overstated and donor commitments at the 1992 Rio Earth Summit have not been met. Aid has been well targeted, however, in that the allocation of biodiversity aid is positively associated with the number of threatened species in recipient countries after controlling for country size, national population, and wealth. Biodiversity aid is also positively associated with indicators of good governance. Our results provide an empirical measure of progress toward international conservation funding targets, a baseline against which future flows can be compared, and information necessary to assess the effectiveness of biodiversity aid.
Optimizing a continuous flow lipid extraction system (CFLES) used for extracting microalgal lipids
Authors: Iqbal Javed , Theegala Chandra
Published: July 2012

A laboratory‐made continuous flow lipid extraction system (CFLES) was devised to extract lipids from microalgae Nannochloropsis sp., a potential feedstock for biodiesel fuel, with a focus to assess the workable temperatures and pressures for future industrial applications. Using conventional solvents, the CFLES recovered 100% of the lipids extracted with conventional Soxhlet extraction. The optimum temperature and pressure were found to be 100 °C and 50 psi, respectively; conditions significantly lower than those normally used in pressurized liquid extractions requiring specialized equipment. Approximately 87% of the extracted oil was successfully transesterified into biodiesel fuel (fatty acid methyl esters). Preliminary calculations based on the tested lab‐scale system indicated savings in energy, solvent consumption, and extraction time as 96%, 80%, and more than 90%, respectively, as compared to Soxhlet extraction. However, the true cost savings can only be assessed at scaled up level. Energy efficiency of CFLES was calculated as 48.9%. Residual water (~70%) in the biomass had no effect on the extraction performance of CFLES, which is expected to help the process economics at scaled up application. The effect of temperature and pressure on the fatty acids profile of Nannochloropsis sp. is also discussed. Based on the existing literature, the authors believe that a pressurized liquid extraction system with continuous solvent flow has not been reported for lipid extraction from Nannochloropsis sp.
Electoral Security of Members of the U.S. House, 1900–2006
Authors: WILKINS ARJUN S.
Published: July 2012

Previous studies have documented that the increase in the incumbency advantage in the 1960s did not decrease the probability of defeat of incumbents in the U.S. House. I define a method for establishing bounds on the probability of incumbent defeat and find that it decreases significantly in the 1950s, before the rise of the incumbency advantage. Incumbency advantage does not have a direct relationship with incumbent defeat rates, raising questions about the use of the incumbency advantage as a means for making inferences about the electoral security of incumbents.
Legislative Term Limits and Fiscal Policy Performance
Authors: LEWIS DANIEL C.
Published: July 2012

Do term limits impede the ability of legislators to effectively set fiscal policy? To address this question, I examine state bond ratings from 1996 to 2009. Bond ratings serve as a valuable indicator of a state's fiscal performance, gauging the risk and uncertainty that investors face when buying these bonds. In addition, bond ratings are important policy ends in themselves. High bond ratings make it easier for states to borrow and raise revenue, while lowering interest rates. Results from analyses of “Term‐Limitedness” and legislator experience suggest that term limits negatively impact a state's fiscal performance, leading to lower bond ratings.
Ethyl pyruvate diminishes the inflammatory response to lipopolysaccharide infusion in horses
Authors: Jacobs C. C. , Holcombe S. J. , Cook V. L. , Gandy J. C. , Hauptman J. G. , Sordillo L. M.
Published: July 2012

Reasons for performing the study:Endotoxaemia contributes to morbidity and mortality in horses with colic due to inflammatory cascade activation. Effective therapeutic interventions are limited for these horses. Ethyl pyruvate (EP), an anti‐inflammatory agent that alters the expression of proinflammatory cytokines, improved survival and organ function in sepsis and gastrointestinal injury in rodents and swine. Therapeutic efficacy of EP is unknown in endotoxaemic horses.

Objectives:Determine the effects of EP on signs of endotoxaemia and expression of proinflammatory cytokines following administration of lipopolysaccharide (LPS) in horses.

Methods:Horses received 30 ng/kg bwt LPS in saline to induce signs of endotoxaemia. Next, horses received lactated Ringer's solution (LRS), (n = 6), 150 mg/kg bwt EP in LRS, (n = 6), or 1.1 mg/kg bwt flunixin meglumine (FM), (n = 6). Controls received saline followed by LRS (n = 6). Physical examinations, behaviour pain scores and blood for clinical pathological testing and gene expression were obtained at predetermined intervals for 24 h.

Results:Lipopolysaccharide infusion produced clinical and clinicopathological signs of endotoxaemia and increased expression of tumour necrosis factor alpha (TNFα), interleukin 6 (IL‐6) and IL‐8 (P<0.001) compared with controls. Leucopenia and neutropenia occurred in all horses that received LPS. Horses treated with EP and FM had significantly (P<0.0001) reduced pain scores compared with horses receiving LPS followed by LRS. Flunixin meglumine was significantly more effective at ameliorating fever compared with EP. Both EP and FM significantly diminished TNFα expression. Ethyl pyruvate significantly decreased, but FM significantly increased, IL‐6 expression. Neither EP nor FM altered IL‐8 expression.

Conclusions and potential relevance:Ethyl pyruvate administered following LPS diminished the clinical effects of endotoxaemia and decreased proinflammatory gene expression in horses. Ethyl pyruvate suppressed expression of proinflammatory cytokines better than FM. However, FM was a superior anti‐pyretic compared with EP. Ethyl pyruvate may have therapeutic applications in endotoxaemic horses.
Finite element analysis of stress in the equine proximal phalanx
Authors: O'Hare L. M. S. , Cox P. G. , Jeffery N. , Singer E. R.
Published: July 2012

Reasons for performing study

To improve understanding of the internal structure of the proximal phalanx (P1), response of the bone to load and possible relation to the pathogenesis of fractures inP1.

Objectives

To model the P1 and replicate the loads experienced by the bone in stance, walk, trot and gallop using finite element analysis.

Methods

The geometry of theP1 was captured using micro‐computed tomography (μCT) and was reconstructed in 3 dimensions. Values for material properties and forces experienced at stance, walk, trot and gallop were taken from the literature and were applied to the reconstructed model. Using the same total load across the proximal articular surface, the model was solved with and without loading of the sagittal groove. Biomechanical performance was then simulated with finite element analysis and evaluated in terms of von Mises stress maps.

Results

Compared with the lowest force simulation equivalent to stance, the effects of the gallop force showed higher levels of stress along the sagittal groove and on the palmar surface just distal to the sagittal groove in both models, with and without the sagittal groove loaded. The results highlighted an area of bone on the dorsal aspect ofP1 that experiences lower stress compared with the rest of the dorsal surface, an effect that was much more apparent when the sagittal groove was not loaded. Qualitative comparison of the models revealed minimal difference in the pattern of von Mises stress between the loaded and unloaded groove models.

Conclusions

The study demonstrates a finite element model ofP1 that produces results consistent with clinical observation. The simulated high stress levels associated with the sagittal groove correspond to the most common site for fractures in the equineP1.

Potential relevance

With refinement of the model and further investigation, it may be possible to improve understanding of the behaviour ofP1 under loading conditions that more closely simulate those experienced in the living animal, leading to a more solid understanding of fractures ofP1.
Hepatic cytochrome P450 mediates interaction between warfarin and Coleus forskohlii extract in vivo and in vitro
Authors: Yokotani Kaori , Chiba Tsuyoshi , Sato Yoko , Taki Yuko , Yamada Shizuo , Shinozuka Kazumasa , Murata Masatsune , Umegaki Keizo
Published: July 2012

Objectives

This study aimed to determine whether Coleus forskohlii extract (CFE) influences the anticoagulant action of warfarin in mice in vivo and its relationship with hepatic cytochrome P450 (CYP).

Methods

Mice were fed various doses of CFE standardised with 10% forskolin in a normal diet for one week, or in protein diets containing 7% and 20% casein (low and normal) for four weeks. They were then administered with warfarin by gavage on the last two days of the treatment regimen, and blood coagulation parameters, as well as hepatic CYP, were analysed at 18 h after the last dose. Direct interaction between CFE and forskolin with CYP2C was evaluated in vitro.

Key findings

CFE dose dependently increased hepatic total CYP content and S-warfarin 7-hydroxylase activity at a dietary level of ≥0.05%. Warfarin-induced anticoagulation was attenuated by CFE in parallel with CYP induction. The findings were similar in mice fed diets containing CFE and different ratios of protein. CFE directly inhibited CYP2C activity in mouse and human liver microsomes in vitro, whereas forskolin was only slightly inhibitory.

Conclusions

CFE attenuates the anticoagulant action of warfarin by inducing hepatic CYP2C; thus, caution is required with the combination of warfarin and dietary supplements containing CFE.
Influence of Track Irregularities in the Catenary-Pantograph Dynamic Interaction
Authors: Carnicero A. , Jimenez-Octavio J. R. , Sanchez-Rebollo C. , Ramos A. , Such M.
Published: July 2012

This paper presents an advanced pantograph-catenary-vehicle-track model, which allows us to analyze the vertical dynamics of the complete system. The developed model is able to evaluate the displacements and the contact force generated in the catenary-pantograph as well as the wheel-track interactions. Nevertheless, this paper focuses on the possible influence of track irregularities on the catenary-pantograph dynamic interaction. From a power spectral density function of the track irregularities, 180 track profiles and their respective catenary-pantograph-vehicle-track simulations have been generated. The wide range of results allows us to obtain some conclusions about the influence of the track profile in the catenary-pantograph behavior.
Large contrast enhancement by sonication assisted cold development process for low dose and ultrahigh resolution patterning on ZEP520A positive tone resist
Authors: Tobing Landobasa Y. M. , Tjahjana Liliana , Zhang Dao Hua
Published: July 2012

The authors demonstrate a robust, low dose, high contrast, and ultrahigh resolution patterning process based on sonication assisted development of ZEP520A positive tone resist in both room and cold temperature. The contrast as high as γ ∼ 25 and γ ∼ 9.14 can readily be achieved in 6 °C and room temperature development, respectively, in diluted n-amyl acetate solution. The high contrast is demonstrated on 90 nm thick ZEP resist at 20 kV acceleration voltage, from which 20 nm thick titanium lift-off of 60 nm pitch lines and 50 nm pitch dots can be successfully achieved.
An evaluation of interference of inflatable penile prostheses with electromagnetic localization and tracking system
Authors: Wang Brian , Tward Jonathan D. , Salter Bill J.
Published: July 2012

Purpose:

The Calypso system is stated by the manufacturer to be contraindicated for cases where the patient has been implanted with a penile prosthesis. This is due to concern for potential metal interference‐related reduction of spatial localization and tracking accuracy. Here we quantify the localization and tracking accuracy of the Calypso system in the presence of inflatable penile prosthesis devices from three most widely used models which account for, essentially, 100% of implants in North America.

Methods:

Phantom studies were first performed to quantify the interference of Calypso localization and tracking accuracy from both varying metal (steel) masses, and from the penile prosthetic devices themselves. The interference of varying steel masses was studied as a function of two factors: (a) the mass and (b) the location of steel material. The Calypso daily quality assurance (QA) phantom with three implanted Beacon® transponders was used to measure any aliasing of position that might occur due to metal interference. After confirming the safety of use in phantom, we implanted Calypso Beacon® transponders in one patient with a previously implanted AMS Model 700 inflatable penile prosthetic device. For each of the 42 delivered treatment fractions, redundant stereotactic ultrasound (US) image guidance was performed to ensure good agreement between US and Calypso guidance.

Results:

We observed that a steel mass of less than 18 g did not cause any detectable positional aliasing for the Calypso tracking function. The mass of metal material measured to exist in the three penile prosthetic devices studied here (MP35N alloy) was approximately 1 g for each. No positional aliasing was observed for the three prosthetic devices in phantom, and good agreement between redundant US and Calypso was also observed in patient.

Conclusions:

Both phantom and patient evaluations with the penile prosthetic devices showed no measurable interference with the Calypso system, thus indicating that accurate Calypso‐based alignments can be performed in the presence of current industry standard inflatable penile prosthetic devices.
Comment on “Exactly solvable models to illustrate supersymmetry and test approximation methods in quantum mechanics,” Am. J. Phys. 79, 755–761 (2011)
Authors: Sprung D. W. L. , Safari Akbar , Sator Nicolas
Published: July 2012

In the paper under discussion, it was observed that the accuracy of WKB approximate binding energies for the exponential potential deteriorates as the energy increases, an apparent violation of the correspondence principle. We show that a careful application of the WKB approximation as it applies to the centrifugal barrier potential leads to improved approximate binding energies of the exponential potential. Our analysis supports the Friedrich and Trost “reflection phase” version of the WKB quantization condition.
Enteroviral meningitis without pleocytosis in children
Authors: Yun Ki Wook , Choi Eun Hwa , Cheon Doo Sung , Lee Jina , Choi Chang Won , Hwang Hee , Kim Beyong Il , Park Kyoung Un , Park Sung Sup , Lee Hoan Jong
Published: July 2012

Objectives

This study aims to describe the clinical characteristics of enteroviral meningitis in association with the absence of cerebrospinal fluid (CSF) pleocytosis.

Design

This was a retrospective analysis of databases of patients diagnosed with enteroviral meningitis by CSF reverse transcription-PCR testing. Presence of CSF non-pleocytosis at each age group was analysed by use of the two criteria. Clinical variables were compared with regard to the presence of CSF pleocytosis. Multiple logistic regression analysis was used to identify factors that were associated with CSF pleocytosis.

Setting

Two hospitals in South Korea, between January 2008 and August 2011.

Patients

390 infants and children with enteroviral meningitis.

Interventions

None.

Main outcome measures

Proportion of enteroviral meningitis without CSF pleocytosis.

Results

Among the 390 patients with enteroviral meningitis, 16–18% did not have CSF pleocytosis. In particular, CSF pleocytosis was not present in 68–77% of the neonates with enteroviral meningitis, demonstrating that the proportion of CSF pleocytosis decreased significantly with age (p<0.001). In multivariate models, younger age (adjusted OR 0.981; 95% CI 0.973 to 0.989), lower peripheral white blood cell count (adjusted OR 0.843; 95% CI 0.791 to 0.899), and shorter interval between onset and lumbar puncture (adjusted OR 0.527; 95% CI 0.315 to 0.882) were associated with the absence of CSF pleocytosis in enteroviral meningitis.

Conclusions

This study demonstrated high proportion of non-pleocytic enteroviral meningitis in young infants and identified several clinical factors that contributed to the absence of CSF pleocytosis. We suggest that CSF enterovirus PCR testing is likely to detect more cases of enteroviral meningitis, especially in young infants.
β-Blocker treatment during pregnancy and adverse pregnancy outcomes: a nationwide population-based cohort study
Authors: Meidahl Petersen Kasper , Jimenez-Solem Espen , Andersen Jon Traerup , Petersen Morten , Brødbæk Kasper , Køber Lars , Torp-Pedersen Christian , Poulsen Henrik Enghusen
Published: July 2012

Objective

To investigate the association between exposure to β-blockers during pregnancy and the risk of being born small for gestational age (SGA), preterm birth and perinatal mortality in a nationwide cohort.

Design

A population-based retrospective cohort study, using the Danish Fertility Database. The authors identified all pregnant women redeeming a prescription for β-blockers using the National Prescription Registry. Multivariate logistic regression models were used to assess the association between exposure and our outcomes.

Setting

Register-based survey.

Participants

911'685 births between 1995 and 2008 obtained from the Danish Fertility Database.

Outcome measures

Being born SGA was defined as having a birth weight below the 10th percentile for the corresponding gestational week. Preterm birth was defined as birth before the 37th gestational week. Perinatal mortality was defined as either death occurring within the first 28 days of life or stillbirth. Before 2004, fetal deaths were recorded as stillbirths if they occurred after 28 weeks of gestation, but since then stillbirth is recorded for deaths after 22 gestational weeks.

Results

The authors identified 2459 pregnancies exposed to β-blockers. β-Blocker exposure during pregnancy was found to be associated with increased risk of SGA (adjusted OR 1.97, 95% CI 1.75 to 2.23), preterm birth (adjusted OR 2.26, 95% CI 2.03 to 2.52) and perinatal mortality (adjusted OR 1.89, 95% CI 1.25 to 2.84). Analyses were adjusted for socioeconomic and maternal variables. The authors found similar risk profiles for pregnancies exposed to labetalol and for pregnancies exposed to other β-blockers.

Conclusions

The authors found that exposure to β-blockers during pregnancy was associated with being born SGA, preterm birth and perinatal mortality. Our findings show that labetalol is not safer than other β-blockers during pregnancy.
Uroradiological screening for upper and lower urinary tract anomalies in patients with hypospadias: a systematic literature review
Authors: Chariatte Vincent , Ramseyer Pascal , Cachat François
Published: July 2012

Introduction

Hypospadias is associated with anomalies of the urinary tract, but the exact prevalence and significance of these anomalies are still controversial.

Objectives

To assess the percentage of patients with hypospadias and associated urological anomalies, either requiring or not requiring medical or surgical attention.

Material and methods

We searched several databases using the following Mesh terms: hypospadias AND urination, ultrasonography, urinary tract/abnormalities, urinary bladder/radiography, ureteral obstruction, hydronephrosis or vesico-ureteral reflux. Type of uroradiological studies performed, type of urological anomalies, medical or surgical interventions, number of patients available, enrolled and undergoing uroradiological studies and number of patients with abnormal uroradiological exams were recorded.

Results

We found 24 studies. Four studies included 100% of available patients. In the other ones, the percentage of patients undergoing uroradiological screening varied from 12 to 82%. Frequency of anomalies varied from 0 to 56%. The most common anomalies were kidney position anomalies, vesico-ureteral reflux and hydronephrosis.

Conclusions

The data published about screening patients with hypospadias for associated anomalies of their urinary tract are of poor quality. The clinical significance of the anomalies found is difficult to evaluate. We found no relationship between the severity of the hypospadias and associated anomalies of the upper or lower urinary tract.
THE EFFECTIVE HAMILTONIAN IN CURVED QUANTUM WAVEGUIDES UNDER MILD REGULARITY ASSUMPTIONS
Authors: KREJČIŘÍK DAVID , ŠEDIVÁKOVÁ HELENA
Published: July 2012

The Dirichlet Laplacian in a curved three-dimensional tube built along a spatial (bounded or unbounded) curve is investigated in the limit when the uniform cross-section of the tube diminishes. Both deformations due to bending and twisting of the tube are considered. We show that the Laplacian converges in a norm-resolvent sense to the well-known one-dimensional Schrödinger operator whose potential is expressed in terms of the curvature of the reference curve, the twisting angle and a constant measuring the asymmetry of the cross-section. Contrary to previous results, we allow the reference curves to have non-continuous and possibly vanishing curvature. For such curves, the distinguished Frenet frame standardly used to define the tube need not exist and, moreover, the known approaches to prove the result for unbounded tubes do not work. To establish the norm-resolvent convergence under the minimal regularity assumptions, we use an alternative frame defined by a parallel transport along the curve and a refined smoothing of the curvature via the Steklov approximation.
Application of metalloporphyrin grafted-graphene oxide for the construction of a novel salicylate-selective electrode
Authors: Poursaberi Tahereh , Hassanisadi Mostafa
Published: July 2012

Due to the vast applications of salicylate ion, development of a simple and selective procedure for its determination is of practical interest. Herein, the unique properties of graphene oxide are combined with the anion selectivity of metalloporphyrins to construct a novel salicylate selective electrode. This electrode is prepared by incorporating Cu(II)–5-4 (aminophenyl)-10,15,20-triphenyl porphyrin grafted-grapheneoxide (CuTPP-GO) into the plasticized poly (vinyl chloride) membrane. Effects of plasticizer nature, Cu TPP-GO concentration and anionic and cationic additives on the potential response of the electrode are investigated. The electrode with the membrane composition of 25% PVC, 50% NPOE, 5% NaTPB and 20% Cu TPP-GO provided the best behavior. This sensor shows a Nernstian response (57.8 mV.decade-1) in the concentration range of 5.0 × 10-1–5.0 × 10-7M with detection limit of 8.0 × 10-8M. sensor response is stable in the pH range of 5–7 and shows a discriminating ability for salicylate compared to most common anions. The sensor was successfully used for determination of salicylate in an aspirin tablet.
Surface Acoustic Wave Properties of Amorphous Ta2O5 and Nb2O5 Thin Films Prepared by Radio Frequency Sputtering
Authors: Kakio Shoji , Hosaka Keiko , Arakawa Mototaka , Ohashi Yuji , Kushibiki Jun-ichi
Published: July 2012

The fundamental acoustic properties of amorphous Ta2O5 and Nb2O5 thin films prepared by RF sputtering were evaluated using a Rayleigh-type surface acoustic wave (SAW) on 128° YX-LiNbO3 and a shear-horizontal-type SAW on 36° YX-LiTaO3. The elastic constants c
11 and c
44 of the thin films were determined from the measured phase velocities of two SAW modes with mutually perpendicular particle motion. Although the elastic constants of the Ta2O5 thin film were found to be approximately 14–17% larger than those of the Nb2O5 thin film, it was clarified that the Ta2O5 thin film has a stronger SAW trapping effect than the Nb2O5 thin film because the density of the former was measured to be 1.5 times higher than that of the latter. On the other hand, the Nb2O5 thin film has a smaller propagation loss for a Rayleigh-type SAW, a lower temperature coefficient of delay, and a higher refractive index than the Ta2O5 thin film.
Low Temperature Elastic Constants and Piezoelectric Coefficients of LiNbO3 and LiTaO3: Resonant Ultrasound Spectroscopy Measurement and Lattice Dynamics Analysis
Authors: Tarumi Ryuichi , Matsuhisa Tomohiro , Shibutani Yoji
Published: July 2012

The complete sets of elastic constants C

i
j
and piezoelectric coefficients e

i
j
for LiNbO3 and LiTaO3 single crystals have been determined by resonant ultrasound spectroscopy (RUS) from ambient temperature to 6 K. Both C

i
j
(T) and e

i
j
(T) of the two crystals monotonically increased as the temperature decreased. The Einstein temperature estimated from Varshni's equation revealed that e
15 and e
22 of LiNbO3 have remarkably low values compared with the acoustic Debye temperature. In addition, the lattice anharmonicity of these piezoelectric coefficients was also extraordinarily low. An analysis based on the group theory and lattice dynamics revealed that both LiNbO3 and LiTaO3 crystals have three types of internal displacement modes: A
1, A
2, and E, and only the E mode affects e
15 and e
22. Therefore, it is reasonable to suppose that the E mode internal displacement is responsible for the unusual behaviors of the tow piezoelectric coefficients.
Picosecond Ultrasound Spectroscopy with a Stable Fiber Laser for Ultrahigh-Frequency-Oscillator Applications: from Nanomechanics to Biosensors
Authors: Ogi Hirotsugu , Kawamoto Tetsuya , Nakamichi Yohei , Hirao Masahiko
Published: July 2012

We developed a stable picosecond-ultrasound-spectroscopy system with a fiber-laser light source. A linearly polarized light pulse with 532 nm wavelength is split into pump and probe light pulses using a polarized beam splitter (PBS). The ultrahigh-frequency acoustic waves excited by the pump light pulse are successfully detected using the delayed probe light pulse with a signal-to-noise ratio higher than that of the traditional titanium–sapphire pulse laser. The wavelength used allows deep inspection of silicon because of less light absorption. The developed system is also applied to a biosensor with an ultrathin Pt film resonator, which shows significantly improved stability at 100 GHz. The amount of frequency change caused by the adsorption of target molecules is of the order of 10-2, which is much higher than that detected with conventional oscillator biosensors by a factor of 104.
Monitoring of Longitudinal-Wave Velocity and Attenuation of SrTiO3at Low Temperatures Using Picosecond Ultrasound Spectroscopy
Authors: Nagakubo Akira , Yamamoto Akihiro , Tanigaki Kenichi , Ogi Hirotsugu , Nakamura Nobutomo , Hirao Masahiko
Published: July 2012

We measured the longitudinal-wave velocity and its attenuation in SrTiO3between 20 and 300 K using picosecond ultrasound spectroscopy. From the temperature dependence of the velocity and attenuation, we monitored the cubic–tetragonal phase transition of SrTiO3near 100 K, whereas no more transitions were indicated below 100 K. From the measured attenuation coefficients, we estimate the relaxation time τ. Because of the ultrahigh frequency measurements, the product ωτ is larger than unity, where the traditional theory for phonon–phonon interaction fails to explain the relaxation time. We then derived the relationship between the relaxation time and attenuation for ωτ>1.
High-Frequency Rheo-Optical Spectroscopy by Ultrasonically Induced Light Diffraction
Authors: Miyake Sho , Matsuoka Tatsuro
Published: July 2012

We improved the apparatus for measuring frequency-dependent complex strain-optical coefficient using ultrasonically induced depolarized light diffraction. Measurements were performed at frequencies from 5 to 75 MHz. The upper frequency limit is three times larger than that obtained in our previous study. We also measured shear relaxation spectra at frequencies from 5 to 205 MHz and compared the results with strain-optical coefficients of 4-cyano-4'-pentylbiphenyl (5CB). The resulting spectra suggest that 5CB has second a relaxation at a high frequency, which has not been observed by heterodyne dynamic light scattering.
Evaluation of Hydrophone Spatial Averaging Effect in Near Field Measurement for Determining Mechanical Index
Authors: Yoshioka Masahiro , Kikuchi Tsuneo
Published: July 2012

An evaluation method of the hydrophone spatial averaging effect in near field measurement using numerically calculated ultrasonic fields for determining the mechanical index related to diagnostic ultrasound is proposed. To demonstrate that the accurate evaluation can be achieved using the method, it is investigated whether a difference between acoustic pressures of an ultrasonic field radiated from a plane circular transducer measured by hydrophones with two different active element sizes is reduced by the correction using the evaluation. The results confirmed that the proposed method is available for evaluating the effect quantitatively.
Imaging of Acoustic Waves in Piezoelectric Ceramics by Coulomb Coupling
Authors: Habib Anowarul , Shelke Amit , Pluta Mieczyslaw , Kundu Tribikram , Pietsch Ullrich , Grill Wolfgang
Published: July 2012

The transport properties of bulk and guided acoustic waves travelling in a lead zirconate titanate (PZT) disc, originally manufactured to serve as ultrasonic transducer, have been monitored by scanned Coulomb coupling. The images are recorded by excitation and detection of ultrasound with local electric field probes via piezoelectric coupling. A narrow pulse has been used for excitation. Broadband coupling is achieved since neither mechanical nor electrical resonances are involved. The velocities of the traveling acoustic waves determined from the images are compared with characteristic velocities calculated from material properties listed by the manufacturer of the PZT plate.
Measurement of Liquid Viscosity and Density Using Single Piezoelectric Resonator with Two Vibration Modes
Authors: Takarada Jun , Wakatsuki Naoto , Mizutani Koichi , Yamamoto Ken
Published: July 2012

We report the results of an experiment on measuring the viscosities and densities of several liquids using a single piezoelectric sensor, since only the numerical results obtained by finite element analysis were reported in our previous paper. The novelty of the sensor is that the viscosity and density can be inferred simply by measuring resonance frequencies in liquid for the vibration in the tangential and normal directions with respect to the contact surface between the sensor and the liquid, while the method suggested as reference requires measurements of resonance frequency and damping of a single vibration mode. By comparing the viscosities and densities measured by the proposed and conventional methods using food oil, the densities were found to correspond to the values measured using a weight meter with an error within 1% and the viscosity was evaluated to be higher than that measured using a viscometer with an error within 10%. The results suggest the possibility of measuring liquid density and viscosity by the proposed method.
Direction of Arrival Estimation Based on Delayed-Sum Method in Reverberation Environment
Authors: Zempo Keiichi , Ebihara Tadashi , Mizutani Koichi
Published: July 2012

Microphone arrays have been used for estimating the direction of arrival (DOA). Owing to intercorrelation among direct and reflected sounds, there are difficulties in estimating DOA using microphone array in highly reverberant environments. The purpose of this research is to estimate the correct DOA in such environments using a small number of microphones with the aid of signal processing. The proposed signal processing uses the relationship that direct signals always arrive earlier than reflected signals. By comparing the delayed-sum signals corresponding to candidate direct signals, the DOA of direct sounds could be determined correctly. We have confirmed the usefulness of the proposed method by conducting several experiments. This proposed method is different from conventional methods because it has high tolerance to the effect of reverberation; it not only enables estimation of DOA but can also be applied to the measurement of the delay of time of flight in reverberant environments.
Reflection and Transmission Behaviors of Ultrasonic Wave at Nano-Air Gap Examined Using Newton's Ring Specimen
Authors: Inoue Masaki , Mihara Tsuyoshi , Tashiro Hatsuzou , Furukawa Takashi
Published: July 2012

Although in previous studies were examined the ultrasonic reflection behaviors at a nano-air gap using a relatively small optical Newton's ring specimen and a commercial acoustic lens, the details of the quantitative ultrasonic behaviors at a nano-air gap have remained unqualified until now. Since the accuracy of estimating these behaviors is directly related to the accuracy of industrial ultrasonic crack sizing, we tried to measure more accurately quantitative ultrasonic behaviors at a nano-air gap in this study. For this purpose, a special highly focused acoustic lens was designed and fabricated and applied to a large optical Newton's ring specimen to obtain accurate and reliable experimental results. Comparisons between the experimental and the conventional small gap theoretical results for a nano-air gap were also carried out. As a result, ultrasonic transmission was found to begin to occur from 60–70 nm air gaps in all the measurements. This finding was largely different from that based on the gap theory. Regarding the cause of this large difference between the experimental and theoretical results, we also examined the influence of the surface roughness of contact plates.
Evaluation of Closed Stress Corrosion Cracks in Ni-Based Alloy Weld Metal Using Subharmonic Phased Array
Authors: Horinouchi Satoshi , Ikeuchi Masako , Shintaku Yohei , Ohara Yoshikazu , Yamanaka Kazushi
Published: July 2012

Closed stress corrosion cracks (SCCs) have been generated in Ni-based alloy weld metal in nuclear power plants. The ultrasonic inspection is difficult because of the crack closure. For the application of new inspection methods and training/educating of inspection engineers, realistic closed SCC specimens are required. However, there is no means for forming such SCC specimens in a reasonable amount of time. Here, we present a two-step method. The first step is to form an open SCC in chemical solution. The second step is to close the SCC by generating oxide films between the crack faces in high-temperature pressurized water (HTPW). To verify the crack closure, we used a closed-crack imaging apparatus, the subharmonic phased array for crack evaluation (SPACE). Consequently, we found that parts of the SCC after 1321 h immersion were closed in the HTPW. Thus, we verified the two-step method for forming realistic closed SCC specimens in a reasonable amount of time.
Equivalent Network Representation for a Liquid-Level Sensor Operating in Trapped-Energy-Mode Thickness Vibration
Authors: Yamada Ken , Koyama Tatsuya , Seto Shuichi
Published: July 2012

The authors have presented a new sensing device that employs a piezoelectric thickness vibrator operating in a trapped-energy mode for detecting slight variation in liquid level. To simulate its sensor operation, the device should be expressed by an equivalent electric network. In this study, the sensor is modeled by modifying an equivalent electric network representing the propagation of a thickness-vibration mode along the piezoelectric plate, and thereby its operation is simulated. The variation in G with the liquid level has been computed using this network model, and the feasibility of the model is confirmed.
Analysis of Characteristics of Coupled Bending Vibrators Used as a Force Sensor
Authors: Sugawara Sumio , Terada Jiro , Takahashi Yusuke
Published: July 2012

The characteristics of the coupled bending vibrator that linearly connects the two bending vibrators are analyzed by the finite-element method, and then the characteristics of the coupled bending vibrator used as a force sensor are investigated. The coupled bending vibrator is applied to an acceleration sensor as a force sensor. The vibration mode in which the two vibrators of the coupled vibrator are out of phase is used here and is very stable because it does not couple with other vibration modes. When the axial force is applied, the amplitude of one vibrator of the coupled vibrator decreases with increase in compressive force. The amplitude of the other vibrator also decreases when the force is applied in the opposite direction. Therefore, the coupled vibrator is used as a force sensor that can estimate the axial force as a change in the amplitude of the vibrator.
Improvement of Characteristics of Frequency-Change-Type Two-Axis Acceleration Sensor
Authors: Sugawara Sumio , Kajiwara Yu
Published: July 2012

The characteristics of a frequency-change-type two-axis acceleration sensor must be improved on the point that an undesirable signal from the other axis direction is detected. The signal is caused by the rotation of mass in the sensor. Two methods for improving the characteristics are proposed here and investigated by finite-element analysis. First, the center of gravity in the sensor was moved to realize a linear motion of mass. As a result, the signal became very small from 5.1 to 0.4%, but the volume of the sensor increased by 28%. Next, the other method of adjusting the dimensions of a bent-type support bar was proposed to realize a linear motion of mass. The rotation was not observed when the signal was decreased to almost zero. The method is very useful from the standpoint of realizing the same volume as the sensor of the prototype.
Coaxial Vibratory Gyroscope Using Two Pairs of Degenerate Modes
Authors: Nakanishi Mami , Wakatsuki Naoto , Mizutani Koichi
Published: July 2012

A gyroscope using two pairs of degenerate modes for wide-range sensing is proposed. We focused on a coaxial resonator composed of a cylinder and a column. To evaluate the characteristics of the proposed gyroscope, we analyzed its frequency response and rotational response both experimentally and numerically. From the frequency response under rotation, there was a difference between the shifts of resonance frequencies of two detecting modes. We also found that the lower-frequency mode had higher sensitivity and the higher-frequency mode had a wider linear region from the rotation response of each mode. These results suggest that high sensitivity for low-speed rotation and a wide linear region for high-speed sensing can be attained simultaneously by a single resonator with the help of two different pairs of degenerate modes.
Quality Factor of Contour-Mode AlN Resonator
Authors: Asai Kengo , Isobe Atsushi
Published: July 2012

We present contour-mode AlN resonator structure and fabrication process for high quality factor (Q-factor). The vibrational energy should be confined to the resonant part of the radial extensional (RE) resonator in order to obtain a high Q-factor and high coupling factor (k
2) from devices made using micro electro mechanical systems (MEMS) technology. In this paper, we discuss how to form a support for the resonant part in a high-precision process. We fabricated simple RE resonators and clarified through experimentation that it is difficult to avoid deterioration of the Q-factor because the RE vibration energy leaks from the resonant part into the silicon substrate through the supporting points. Next, we fabricated tuning-fork RE resonators by using the three-etching-process method and clarified through experimentation that this method is useful for forming the resonant part into the correct circular shape and avoiding energy leakage.
Spurious Suppression without Energy Dissipation in Aluminum–Nitride-Based Thin-Film Bulk Acoustic Resonator Using Thin Ring on Electrode Edge
Authors: Hara Motoaki , Kuwano Hiroki
Published: July 2012

We examined the suppression of spurious responses beneath the resonant frequency in an aluminum-nitride-based thin-film bulk acoustic resonator (FBAR) by a two-dimensional (2D) finite element method (FEM) and dispersion analysis of waves. The results confirmed that the 0th-order asymmetric mode (A
0 mode) influences the resonance characteristics. As a result of these findings, we propose a structure having a thin ring on the electrode edge to take advantage of this A
0 mode in suppressing spurious responses.
Improvement of Temperature Characteristics of Boundary Acoustic Wave Resonators Using Multilayered Electrodes
Authors: Mimura Masakazu , Tamazaki Daisuke , Yamane Takashi , Kando Hajime
Published: July 2012

In this paper, we describe a new boundary acoustic wave structure employing multilayered metal electrodes with a high-density metal and a low-density metal. By using this structure, such as Pt/Al/Pt, the electromechanical coupling coefficient (k
2) and temperature coefficient of frequency (TCF) of the boundary acoustic wave can be changed. We theoretically studied the dependence of the energy distribution of the boundary wave on the position of the total electrode gravity center when the electrode layer structure is changed. It was experimentally confirmed that k
2 and TCF can be changed simultaneously. By using this structure, we developed a novel filter with good electrical characteristics, and a very small variation of the filter characteristic with temperature (almost zero TCF) was successfully realized.