bluuebunny/crossref_metadata_2025 huggingface dataset:
An Exploratory Study of Salivary Calcitonin Gene‐Related Peptide Levels Relative to Acute Interventions and Preventative Treatment With OnabotulinumtoxinA in Chronic Migraine
Authors: Cady Roger , Turner Ira , Dexter Kent , Beach M. E. , Cady Ryan , Durham Paul
Published: October 2013

Objective

To determine if baseline/interictal saliva calcitonin gene‐related peptide (CGRP) levels would be lower in subjects with chronic migraine receiving onabotulinumtoxinA compared with those receiving saline.

Background

CGRP is considered central to the pathogenesis of episodic migraine, but its relationship to chronic migraine is less understood. OnabotulinumtoxinA is an effective treatment for chronic migraine and has been demonstrated to inhibit the vesicular release of CGRP.

Methods

This was an exploratory, randomized, placebo‐controlled, crossover pilot study of 20 subjects that received onabotulinumtoxinA and saline injection (placebo). The amount of CGRP in saliva samples collected on a nonheadache or low headache day, and prior to and after treatment of a headache exacerbation was measured. Daily headache records, medications, and response to treatment were recorded in a diary.

Results

A decrease in baseline/interictal saliva CGRP levels for subjects receiving onabotulinumtoxinA from 39.4 ± 7.5 pg CGRP/mg total protein after the first month to 25.5 ± 4.1 pg after the third month was observed. However, this difference did not reach significance nor was it significant when compared to the saline treatment. There was a reduction in the number of headache days for both onabotulinumtoxinA and saline over baseline throughout the active phases of the study. However, there was no statistical difference in headache days between groups. Subjects with a greater than 50% response to onabotulinumtoxinA had better 2‐hour pain relief with acute treatment than non‐responders to onabotulinumtoxinA or saline.

Conclusion

While CGRP levels were not elevated during a migraine attack in chronic migraine subjects as has been reported in episodic migraine, there was an overall decrease in the baseline/interictal levels in response to onabotulinumtoxinA.
Geochemistry of eclogite‐ and blueschist‐facies rocks from the Bantimala Complex, South Sulawesi, Indonesia: Protolith origin and tectonic setting
Authors: Maulana Adi , Christy Andrew G. , Ellis David J. , Imai Akira , Watanabe Koichiro
Published: October 2013

We present the first data on bulk‐rock major and trace element compositions for a suite of eclogite‐ and blueschist‐facies rocks from the Bantimala Complex, Indonesia, with the aim of better constraining the protolith origins and nature of the subducted crust. The eclogites can be classified into two groups: glaucophane‐rich eclogite and glaucophane‐free eclogite, whereas the blueschists are divided into albite–epidote glaucophanite and quartz–glaucophane schists. SiO2 contents of the eclogites are 43.3–49.6 wt%, with Na2O + K2O contents 3.7–4.7 wt%. The blueschists show a wider range of compositions, with SiO2 = 40.7–63.8 wt% and Na2O + K2O = 2.7–4.5 wt%. Trace element data suggest that the eclogite protoliths include both enriched and normal mid‐oceanic ridge basalt (E‐MORB and N‐MORB) and also gabbroic cumulates. The blueschists show more variation in protoliths, which include N‐MORB, Oceanic Island Basalt (OIB) and Island Arc Basalt (IAB). Plots of element concentrations against the immobile Zr show considerable mobility of large ion lithophiles but not of high field‐strength elements during high‐pressure metamorphism, and indicate that the high SiO2 content of some blueschists is probably due to metasomatism by a LILE‐rich siliceous aqueous fluid. Strong correlations between K, Rb, Ba and Cs suggests that enrichment of these elements occurred by a single process. All the protoliths were subducted, metamorphosed to blueschist/eclogite‐facies and subsequently exhumed. It is noteworthy that the samples deduced to have come from thicker‐crust environments (OIB, IAB) were subducted to shallower depths (blueschist‐facies) than MORB‐derived samples, all except one of which reached eclogite‐facies conditions. The geochemical data of this study demonstrate the variety of ocean floor types that were subducted under the southeast margin of Sundaland in the late Jurassic period.
Consumers' willingness to buy products with environmental and ethical claims: the roles of social representations and social identity
Authors: Bartels Jos , Onwezen Marleen C.
Published: October 2013

This study investigates how social representations and consumers' identification with organic food consumers affects intentions to buy products that make environmental and ethical claims. For the purposes of the study, an online panel study was conducted on a representative sample of consumers (n = 1006) in the United Kingdom. The results demonstrate that consumers who are adherent to natural foods or technology and do not perceive food as a necessity are more willing to buy environmentally friendly and ethical products. There seems to be no relationship between perceptions of food as a source of enjoyment and intentions to buy sustainable products. Finally, social identification with the organic consumer is positively related with the intentions to buy products that make environmental and ethical claims. The current research demonstrates that both individual perceptions of food and consumers' perceptions of the social environment play an important role in promoting environmentally friendly and ethical behaviour.
Comparison of the efficacy of sitagliptin and glimepiride dose‐up in Japanese patients with type 2 diabetes poorly controlled by sitagliptin and glimepiride in combination
Authors: Shimoda Seiya , Iwashita Shinsuke , Sekigami Taiji , Furukawa Noboru , Matsuo Yasuto , Ichimori Shinji , Goto Rieko , Maeda Takako , Watanabe Eiichiro , Kondo Tatsuya , Matsumura Takeshi , Motoshima Hiroyuki , Nishida Kenro , Araki Eiichi
Published: October 2013

Aims/Introduction

The goal of the study was to examine the effects of sitagliptin dose‐up or glimepiride dose‐up in Japanese patients with type 2 diabetes who were controlled inadequately by sitagliptin and glimepiride in combination.

Materials and Methods

A multicenter, prospective, randomized, open‐label study was carried out in 50 patients with type 2 diabetes treated with sitagliptin and low‐dose glimepiride. The patients were randomly assigned to receive the addition of 50 mg/day sitagliptin or 0.5 mg/day glimepiride. The primary end‐point was the percentage change in glycated hemoglobin (HbA1c).

Results

During a follow‐up period, the difference in the percentage changes in HbA1c between the two groups was not significant (P = 0.13). However, HbA1c was significantly decreased by glimepiride dose‐up (P < 0.01 vs baseline), but not by sitagliptin dose‐up (P = 0.74). Univariate linear regression analyses showed that the percentage change in HbA1c was significantly associated with the serum level of arachidonic acid (AA) in both groups.

Conclusions

There was no significant difference in the HbA1c‐lowering effects between the two groups. However, a significant HbA1c‐lowering effect from baseline of glimepiride dose‐up was found, and the AA level showed a negative correlation with the decrease in HbA1c in the sitagliptin dose‐up group, but a positive correlation in the glimepiride dose‐up group. These findings suggest that the AA level is associated with HbA1c reduction in response to dose‐up with these drugs in patients with type 2 diabetes in a combination therapy with sitagliptin and glimepiride. This trial was registered with UMIN (no. 000009544).
Factors influencing macrosomia in pregnant women in a tertiary care hospital in Malaysia
Authors: Yadav Hematram , Lee Nagarajah
Published: October 2013

Aim

To identify the risk factors influencing the development of macrosomia among pregnant women and to develop a regression model to predict macrosomia.

Methods

A cross‐sectional study was conducted in a tertiary hospital in Malaysia involving 2332 pregnant women. The data was retrospectively collected from the obstetrics and gynecology department. The factors that influence fetal weight were collected from the antenatal cards and any additional information was collected by face‐to‐face interview using a questionnaire. A multiple regression model was developed to predict macrosomia using SPSS ver. 18.

Results

The significant variables that influence macrosomia in this study were mother's age, mother's body mass index (BMI), weight gain, parity, mother's ethnicity, father's BMI, gestational week, diabetes during pregnancy and neonatal sex. Diabetes during pregnancy is an important risk factor for macrosomia; by using this parameter alone the risk of macrosomia can be predicted with a sensitivity rate of 70% and specificity of 70%. By including other maternal factors such as maternal age, pre‐pregnancy BMI, weight gain, parity, ethnicity, as well as father's BMI, gestational weeks and neonate sex, the sensitivity and specificity were improved to 80% and 75%, respectively.

Conclusion

A regression model was developed and this could be used in health centers to predict macrosomia for purpose of referral to higher centers.
Patents as Signals for Startup Financing
Authors: Conti Annamaria , Thursby Jerry , Thursby Marie
Published: October 2013

We examine the role of patents as signals used to reduce information asymmetries in entrepreneurial finance. A theoretical model gives conditions for a unique separating equilibrium in which startup founders file for patents to signal invention quality to investors, as well as appropriating value. The theory allows for heterogeneous investors and examines the optimal match of different types of startups, as defined by the quality of their technology, to investors who differ in the amount of non financial capital they provide. The empirical analysis is consistent with the model's predictions using a novel dataset of Israeli startups that received external funding during the period 1994–2011.
Non‐Obviousness and Screening
Authors: Kou Zonglai , Rey Patrick , Wang Tong
Published: October 2013

The paper offers a novel justification for the non‐obviousness patentability requirement. An innovation involves two stages: research results in a technology blueprint, which development transforms into a profitable activity. An innovator, who is either efficient or inefficient, must rely on outside finance for the development. Only patented technologies are developed. Strengthening the non‐obviousness requirement alleviates adverse selection by discouraging inefficient innovators from doing research, but creates inefficiencies by excluding marginal innovations. We show that it is socially optimal to raise the non‐obviousness requirement so as to exclude bad innovators; we also provide several robustness checks and discuss the policy implications.
The prevalence of vitamin D deficiency in children in the Northern Territory
Authors: Dyson Amanda , Pizzutto Susan J , MacLennan Carolyn , Stone Monique , Chang Anne B
Published: October 2013

Aims

The primary aim of this study was to determine the frequency of vitD deficiency/insufficiency in an opportunistic sample of Northern Territory (NT) children. The secondary aim was to evaluate whether: (i) 25(OH)vitD (25(OH)D) levels differ between Indigenous/non‐Indigenous children; and (ii) VitD insufficiency is associated with increased acute/infective hospitalisations.

Methods

Twenty‐five (OH)D levels were measured in 98 children <16 years between August 2011 and January 2012 (children hospitalised acutely/non‐acutely and well children from other studies based in Darwin). VitD deficiency was defined as 25(OH)D < 50 nmol/L, and insufficiency was postulated to be <75 nmol/L. Demographic data were collected, and computer records were reviewed.

Results

Median age was 59 months (range 2–161); 3.1% were vitD deficient, 19.4% insufficient. There was no significant difference in mean 25(OH)D level between Indigenous (93.2, standard deviation (SD) 21.9, n = 42) and non‐Indigenous (97.3, SD 27.9, n = 56) children (P = 0.32). Median number of hospitalisations/year were similar (P = 0.319) between vitD sufficient (0.34, range 0–12, n = 76) and insufficient (0.22, 0–6, n = 22) children. There was no significant difference between number of infective admissions per year between vitD sufficient/insufficient groups (P = 0.119).

Conclusions

Compared with US data (19% deficient, 65% insufficient) fewer NT children are vitD deficient/insufficient. In our limited sample, being vitD insufficient was not associated with increased acute/infective hospitalisations, but a larger unbiased sample of NT children is needed. More information is needed about the optimum level of vitD for non‐bone‐related health in children.
A NON‐GAUSSIAN FAMILY OF STATE‐SPACE MODELS WITH EXACT MARGINAL LIKELIHOOD
Authors: Gamerman Dani , dos Santos Thiago Rezende , Franco Glaura C.
Published: October 2013

The Gaussian assumption generally employed in many state‐space models is usually not satisfied for real time series. Thus, in this work, a broad family of non‐Gaussian models is defined by integrating and expanding previous work in the literature. The expansion is obtained at two levels: at the observational level, it allows for many distributions not previously considered, and at the latent state level, it involves an expanded specification for the system evolution. The class retains analytical availability of the marginal likelihood function, uncommon outside Gaussianity. This expansion considerably increases the applicability of the models and solves many previously existing problems such as long‐term prediction, missing values and irregular temporal spacing. Inference about the state components can be performed because of the introduction of a new and exact smoothing procedure, in addition to filtered distributions. Inference for the hyperparameters is presented from the classical and Bayesian perspectives. The results seem to indicate competitive results of the models when compared with other non‐Gaussian state‐space models available. The methodology is applied to Gaussian and non‐Gaussian dynamic linear models with time‐varying means and variances and provides a computationally simple solution to inference in these models. The methodology is illustrated in a number of examples.
Growth stimulation in inflorescences of an Arabidopsis tubulin mutant under microgravity conditions in space
Authors: Hoson T. , Soga K. , Wakabayashi K. , Hashimoto T. , Karahara I. , Yano S. , Tanigaki F. , Shimazu T. , Kasahara H. , Masuda D. , Kamisaka S.
Published: October 2013

Cortical microtubules are involved in plant resistance to hypergravity, but their roles in resistance to 1 g gravity are still uncertain. To clarify this point, we cultivated an Arabidopsis α‐tubulin 6 mutant (tua6) in the Cell Biology Experiment Facility on the Kibo Module of the International Space Station, and analyzed growth and cell wall mechanical properties of inflorescences. Growth of inflorescence stems was stimulated under microgravity conditions, as compared with ground and on‐orbit 1 g conditions. The stems were 10–45% longer and their growth rate 15–55% higher under microgravity conditions than those under both 1 g conditions. The degree of growth stimulation tended to be higher in the tua6 mutant than the wild‐type Columbia. Under microgravity conditions, the cell wall extensibility in elongating regions of inflorescences was significantly higher than the controls, suggesting that growth stimulation was caused by cell wall modifications. No clear differences were detected in any growth or cell wall property between ground and on‐orbit 1 g controls. These results support the hypothesis that cortical microtubules generally play an important role in plant resistance to the gravitational force.
Effects of seed burial on germination, protein mobilisation and seedling survival in Dodonaea viscosa
Authors: Benítez‐Rodríguez L. , Gamboa‐deBuen A. , Sánchez‐Coronado M. E. , Alvarado‐López S. , Soriano D. , Méndez I. , Vázquez‐Santana S. , Carabias‐Lillo J. , Mendoza A. , Orozco‐Segovia A.
Published: October 2013

Ecological restoration of disturbed areas requires substantial knowledge of the germination of native plants and the creation of novel methods to increase seedling establishment in the field. We studied the effects of soil matrix priming on the germination of Dodonaea viscosa seeds, which exhibit physical dormancy. To this end, we buried both pre‐scarified (in H2SO4, 3 min) and non‐pre‐scarified seeds in the Parque Ecológico de la Ciudad de México. After seeds were unearthed, they were post‐scarified for 0, 2, 6 and 10 min and their germination percentages compared to the germination of a control batch of laboratory‐stored seeds. For both control and unearthed seeds, the protein pattern was determined in the enriched storage protein fraction in SDS‐PAGE gels stained with Coomassie blue. Percentage germination increased as the scarification time increased. Pre‐scarification significantly increased percentage germination of post‐scarified seeds in relation to the control and non‐pre‐scarified seeds. In seeds unearthed from the forest site, the buried pre‐scarified seeds had relatively high percentage germination, even in the absence of post‐scarification treatment. A 48‐kDa protein was not found in unearthed, pre‐scarified seeds nor in the control germinated seeds, indicating that mobilisation of this protein occurred during soil priming. Burying seeds for a short period, including the beginning of the rainy season, promoted natural priming, which increased protein mobilisation. Functionally, priming effects were reflected in high percentage seedling survival in both the shade house and the field. Seed burial also reduced the requirement for acidic post‐scarification.
Relation between emotional distress and heart rate variability in patients with an implantable cardioverter‐defibrillator
Authors: Hoogwegt Madelein T. , Pedersen Susanne S. , Theuns Dominic A. M. J. , Kupper Nina
Published: October 2013

We investigated the relationship between Type D personality, depression, and anxiety, and heart rate variability (HRV) in 64 patients with an implantable cardioverter‐defibrillator (ICD). HRV was obtained via 24‐h Holter monitoring, and 24‐h, 30‐min daytime rest and 30‐min nighttime sleep HRV were analyzed. In adjusted analyses, significant associations (standard deviation of normal‐to‐normal [NN] intervals [SDNN]: p = .043; standard deviation of NN intervals over 5‐min periods [SDANN]: p = .010) and a trend (HRV triangular index: p = .09) were found for Type D personality, and trends were found for depression (lower RMSSD: p = .10; lower pNN50: p = .09). During daytime rest, similar results were found for anxiety and depression. During sleep, only noteworthy adjusted associations were found for depression (lower root mean square of successive differences in NN intervals [RMSSD]: p = .06; lower pNN50: p = .043). A Benjamini‐Hochberg correction for multiple testing led to reduction of the number of significant relationships, but there was still support for lower autonomic control patients with Type D personality and depression. Future research with larger sample sizes is warranted.
Market Size, Local Sourcing and Policy Competition for Foreign Direct Investment
Authors: Ma Jie
Published: October 2013

This paper analyzes policy competition for a foreign‐owned monopolist firm between two asymmetric countries. In particular, one country has a larger economy than the other country. At the same time, the small country produces an intermediate good for the final good production, while the large country does not. We show that whether a country will win foreign direct investment (FDI) competition is determined by the interaction between relative transport costs of intermediate and final goods and the market size of the large country relative to that of the small country; and policy competition for FDI may Pareto weakly improve national welfare of the competing countries.
Activation, Public Employment Services and their Clients: The Role of Social Class in a Continental Welfare State
Authors: Ludwig‐Mayerhofer Wolfgang , Behrend Olaf , Sondermann Ariadne
Published: October 2013

This article fills a gap in the existing literature by investigating how public employment service (PES) staff actually deal with their clients under a continental regime of activation. The results reported here are based on interviews both with PES staff and their unemployed clients in Germany. We argue that due to its Bismarckian origins as an insurance‐based system of ‘unemployment protection’, Germany's system of unemployment compensation is attractive not only for the marginalized, but also for core workers. As a result, PES staff deal with clients from very heterogeneous class backgrounds. We demonstrate that social class is a significant factor in client outcomes, and that earlier research has perhaps overemphasized the role of frontline staff as ‘street‐level bureaucrats’. While staff do have considerable power, the result of the encounters between the administration and clients also depends on the capabilities of the clients, which, in turn, are strongly related to social class.
The developmental stages of synaptic plasticity
Authors: Lohmann Christian , Kessels Helmut W.
Published: October 2013

Abstract  The brain is programmed to drive behaviour by precisely wiring the appropriate neuronal circuits. Wiring and rewiring of neuronal circuits largely depends on the orchestrated changes in the strengths of synaptic contacts. Here, we review how the rules of synaptic plasticity change during development of the brain, from birth to independence. We focus on the changes that occur at the postsynaptic side of excitatory glutamatergic synapses in the rodent hippocampus and neocortex. First we summarize the current data on the structure of synapses and the developmental expression patterns of the key molecular players of synaptic plasticity, N‐methyl‐d‐aspartate (NMDA) and α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid (AMPA) receptors, as well as pivotal kinases (Ca2+/calmodulin‐dependent protein kinase II, protein kinase A, protein kinase C) and phosphatases (PP1, PP2A, PP2B). In the second part we relate these findings to important characteristics of the emerging network. We argue that the concerted and gradual shifts in the usage of plasticity molecules comply with the changing need for (re)wiring neuronal circuits.
Distribution and Ca2+ signalling of fibroblast‐like (PDGFRα+) cells in the murine gastric fundus
Authors: Baker Salah A. , Hennig Grant W. , Salter Anna K. , Kurahashi Masaki , Ward Sean M. , Sanders Kenton M.
Published: October 2013

Key points

A new class of interstitial cells, PDGFRα+ cells, is distributed densely in the proximal stomachs of mice.

PDGFRα+ cells express the molecular apparatus necessary for transduction of inputs from enteric inhibitory motor neurons.

PDGFRα+ cells generate spontaneous Ca2+ transients and display dynamic Ca2+ oscillations in response to purines.

Purinergic responses are mediated by P2Y1 receptors and by Ca2+ release from intracellular Ca2+ stores.

Ca2+ release in PDGFRα+ cells is the likely means by which purinergic neurotransmitters activate Ca2+‐activated K+ channels (SK) and hyperpolarization in GI muscles to elicit inhibitory motor responses.

Spontaneous Ca2+ transients may be a means of regulating basal excitability of fundus muscles and release of purines from motor neurons may contribute to the control of pressure during filling in the proximal stomach.

Abstract  Platelet‐derived growth factor receptor α positive (PDGFRα+) cells are suggested to mediate purinergic inputs in GI muscles, but the responsiveness of these cells to purines in situ has not been evaluated. We developed techniques to label and visualize PDGFRα+ cells in murine gastric fundus, load cells with Ca2+ indicators, and follow their activity via digital imaging. Immunolabelling demonstrated a high density of PDGFRα+ cells in the fundus. Cells were isolated and purified by fluorescence‐activated cell sorting (FACS) using endogenous expression of enhanced green fluorescent protein (eGFP) driven off the Pdgfra promoter. Quantitative PCR showed high levels of expression of purinergic P2Y1 receptors and SK3 K+ channels in PDGFRα+ cells. Ca2+ imaging was used to characterize spontaneous Ca2+ transients and responses to purines in PDGFRα+ cells in situ. ATP, ADP, UTP and β‐NAD elicited robust Ca2+ transients in PDGFRα+ cells. Ca2+ transients were also elicited by the P2Y1‐specific agonist (N)‐methanocarba‐2MeSADP (MRS‐2365), and inhibited by MRS‐2500, a P2Y1‐specific antagonist. Responses to ADP, MRS‐2365 and β‐NAD were absent in PDGFRα+ cells from P2ry1(−/−) mice, but responses to ATP were retained. Purine‐evoked Ca2+ transients were mediated through Ca2+ release mechanisms. Inhibitors of phospholipase C (U‐73122), IP3 (2‐APB), ryanodine receptors (Ryanodine) and SERCA pump (cyclopiazonic acid and thapsigargin) abolished Ca2+ transients elicited by purines. This study provides a link between purine binding to P2Y1 receptors and activation of SK3 channels in PDGFRα+ cells. Activation of Ca2+ release is likely to be the signalling mechanism in PDGFRα+ cells responsible for the transduction of purinergic enteric inhibitory input in gastric fundus muscles.
Capturing Three-Dimensional In Vivo Lumbar Intervertebral Joint Kinematics Using Dynamic Stereo-X-Ray Imaging
Authors: Aiyangar Ameet K. , Zheng Liying , Tashman Scott , Anderst William J. , Zhang Xudong
Published: October 2013

Availability of accurate three-dimensional (3D) kinematics of lumbar vertebrae is necessary to understand normal and pathological biomechanics of the lumbar spine. Due to the technical challenges of imaging the lumbar spine motion in vivo, it has been difficult to obtain comprehensive, 3D lumbar kinematics during dynamic functional tasks. The present study demonstrates a recently developed technique to acquire true 3D lumbar vertebral kinematics, in vivo, during a functional load-lifting task. The technique uses a high-speed dynamic stereo-radiography (DSX) system coupled with a volumetric model-based bone tracking procedure. Eight asymptomatic male participants performed weight-lifting tasks, while dynamic X-ray images of their lumbar spines were acquired at 30 fps. A custom-designed radiation attenuator reduced the radiation white-out effect and enhanced the image quality. High resolution CT scans of participants' lumbar spines were obtained to create 3D bone models, which were used to track the X-ray images via a volumetric bone tracking procedure. Continuous 3D intervertebral kinematics from the second lumbar vertebra (L2) to the sacrum (S1) were derived. Results revealed motions occurring simultaneously in all the segments. Differences in contributions to overall lumbar motion from individual segments, particularly L2–L3, L3–L4, and L4–L5, were not statistically significant. However, a reduced contribution from the L5–S1 segment was observed. Segmental extension was nominally linear in the middle range (20%–80%) of motion during the lifting task, but exhibited nonlinear behavior at the beginning and end of the motion. L5–S1 extension exhibited the greatest nonlinearity and variability across participants. Substantial AP translations occurred in all segments (5.0 ± 0.3 mm) and exhibited more scatter and deviation from a nominally linear path compared to segmental extension. Maximum out-of-plane rotations (<1.91 deg) and translations (<0.94 mm) were small compared to the dominant motion in the sagittal plane. The demonstrated success in capturing continuous 3D in vivo lumbar intervertebral kinematics during functional tasks affords the possibility to create a baseline data set for evaluating the lumbar spinal function. The technique can be used to address the gaps in knowledge of lumbar kinematics, to improve the accuracy of the kinematic input into biomechanical models, and to support development of new disk replacement designs more closely replicating the natural lumbar biomechanics.
Dry etching techniques for active devices based on hexagonal boron nitride epilayers
Authors: Grenadier Samuel , Li Jing , Lin Jingyu , Jiang Hongxing
Published: October 2013

Hexagonal boron nitride (hBN) has emerged as a fundamentally and technologically important material system owing to its unique physical properties including layered structure, wide energy bandgap, large optical absorption, and neutron capture cross section. As for any materials under development, it is necessary to establish device processing techniques to realize active devices based on hBN. The authors report on the advancements in dry etching techniques for active devices based on hBN epilayers via inductively coupled plasma (ICP). The effect of ICP radio frequency (RF) power on the etch rate and vertical side wall profile was studied. The etching depth and angle with respect to the surface were measured using atomic force microscopy showing that an etching rate ∼1.25 μm/min and etching angles >80° were obtained. Profilometer data and scanning electron microscope images confirmed these results. This work demonstrates that SF6 is very suitable for etching hBN epilayers in RF plasma environments and can serve as a guide for future hBN device processing.
A full‐spectral Bayesian reconstruction approach based on the material decomposition model applied in dual‐energy computed tomography
Authors: Cai C. , Rodet T. , Legoupil S. , Mohammad‐Djafari A.
Published: October 2013

Purpose:

Dual‐energy computed tomography (DECT) makes it possible to get two fractions of basis materials without segmentation. One is the soft‐tissue equivalent water fraction and the other is the hard‐matter equivalent bone fraction. Practical DECT measurements are usually obtained with polychromatic x‐ray beams. Existing reconstruction approaches based on linear forward models without counting the beam polychromaticity fail to estimate the correct decomposition fractions and result in beam‐hardening artifacts (BHA). The existing BHA correction approaches either need to refer to calibration measurements or suffer from the noise amplification caused by the negative‐log preprocessing and the ill‐conditioned water and bone separation problem. To overcome these problems, statistical DECT reconstruction approaches based on nonlinear forward models counting the beam polychromaticity show great potential for giving accurate fraction images.

Methods:

This work proposes a full‐spectral Bayesian reconstruction approach which allows the reconstruction of high quality fraction images from ordinary polychromatic measurements. This approach is based on a Gaussian noise model with unknown variance assigned directly to the projections without taking negative‐log. Referring to Bayesian inferences, the decomposition fractions and observation variance are estimated by using the joint maximuma posteriori (MAP) estimation method. Subject to an adaptive prior model assigned to the variance, the joint estimation problem is then simplified into a single estimation problem. It transforms the joint MAP estimation problem into a minimization problem with a nonquadratic cost function. To solve it, the use of a monotone conjugate gradient algorithm with suboptimal descent steps is proposed.

Results:

The performance of the proposed approach is analyzed with both simulated and experimental data. The results show that the proposed Bayesian approach is robust to noise and materials. It is also necessary to have the accurate spectrum information about the source‐detector system. When dealing with experimental data, the spectrum can be predicted by a Monte Carlo simulator. For the materials between water and bone, less than 5% separation errors are observed on the estimated decomposition fractions.

Conclusions:

The proposed approach is a statistical reconstruction approach based on a nonlinear forward model counting the full beam polychromaticity and applied directly to the projections without taking negative‐log. Compared to the approaches based on linear forward models and the BHA correction approaches, it has advantages in noise robustness and reconstruction accuracy.
Acoustic propagation using the direct simulation Monte Carlo method
Authors: Danforth Amanda L. , Long Lyle N.
Published: October 2013

In the simulation of fluid dynamics, one can either treat the fluid as a continuum or as discrete particles. Although popular for acoustics, the continuum model is limited to small Knudsen numbers (the ratio of mean free path to a length scale). Particle methods are necessary for, but not limited to, problems with Knudsen numbers greater than 0.1, which can occur in shockwaves, microdevices, or rarefied gases. Some well known particle methods include Molecular Dynamics, Monte Carlo methods, and the Lattice Boltzmann Method. The Direct Simulation Monte Carlo (DSMC) method describes gas flows through direct physical modeling of particle motions and collisions. DSMC can model linear and nonlinear acoustics, as well as the details of viscous dissipation. DSMC results will be shown and compared with continuum theory. A DSMC method has been implemented for 1-dimensional linear and nonlinear acoustics problems on parallel computers using object-oriented C++ and the message passing interface (MPI). The code has been run on large Beowulf clusters. The results have been compared to solutions to the linear wave equation. The complete paper will include two-dimensional solutions as well as comparisons to nonlinear continuum results. [Work supported by Consortium for Education in Many-Body Applications, Grant No. NSF-DGE-9987589.]
Acoustic comparisons of Japanese and English vowels produced by native speakers of Japanese
Authors: Nishi Kanae , Akahane-Yamada Reiko , Kubo Rieko , Strange Winifred
Published: October 2013

This study explored acoustic similarities/differences between Japanese (J) and American English (AE) vowels produced by native J speakers and compared production patterns to their perceptual assimilation of AE vowels [Strange et al., J. Phonetics 26, 311–344 (1998)]. Eight male native J speakers who had served as listeners in Strange et al. produced 18 Japanese (J) vowels (5 long-short pairs, 2 double vowels, and 3 long-short palatalized pairs) and 11 American English (AE) vowels in /hVbopena/ disyllables embedded in a carrier sentence. Acoustical parameters included formant frequencies at syllable midpoint (F1/F2/F3), formant change from 25% to 75% points in syllable (formant change), and vocalic duration. Results of linear discriminant analyses showed rather poor acoustic differentiation of J vowel categories when F1/F2/F3 served as input variables (60% correct classification), which greatly improved when duration and formant change were added. In contrast, correct classification of J speakers’ AE vowels using F1/F2/F3 was very poor (66%) and did not improve much when duration and dynamic information were added. J speakers used duration to differentiate long/short AE vowel contrasts except for mid-to-low back vowels; these vowels were perceptually assimilated to a single Japanese vowel, and are very difficult for Japanese listeners to identify.
The effect of the dialect on perception of words with different pitch accents in Japanese
Authors: Okamura Kyoko
Published: October 2013

Eastern and western dialects of Japanese have been noted to have different pitch accent systems. This study explores how Japanese words with and without accent are perceived by speakers of different dialects. Otake and Cutler (J. Phonet. 27, 229–253) found little difference in identification between Tokyo and the other variety of speakers. In current study, a speaker of Tokyo Japanese produced words with and without an accent. Using the STRAIGHT resynthesis system, the F0 of the accented mora was lowered in 7 steps to the level of the unaccented form, and raised in the unaccented mora to the level of the accented form. Continua were presented to listeners from western and eastern Japan. Listeners exhibit consistent category boundaries according to the difference in F0 between the target mora and the following one. In addition, reaction times are greater near the category boundary, and subjective measures of confidence decrease near the boundary. Speakers from different dialects showed similar identification patterns. Reaction times and confidence measures were different overall, but exhibited the same pattern for the two groups. These results indicate that the accent is a uniform phonetic entity for the two dialects, despite numerous differences in the accentual systems.
Is there a correlation between Japanese L2 learner’s perception of English stressed words and acoustic features?
Authors: Asano Keiko , Isei-Jakkola Toshiko
Published: October 2013

Is there a correlation between Japanese L2 learner’s perception of English stressed words and acoustic features? [Keiko Asano (Yokohama National University, ll-ed@ynu.ac.jp) and Toshiko Isei-jaakkola (University of Helsinki)]. It is well known that the Japanese have weakness in listening to unstressed words in English, but there are less data on their perception of stressed words. Thus, the listening tests and the acoustic experiments were conducted in terms of (1) relevancy of difficulites depending on part of speech and their English proficiency, (2) the relationship between pitch and intensity of stressed words, and (3) if there is a correlation between their perception and experimental data. In the listening test, an English prose read by an American male speaker was used. The 150 Japanese L2 learners were assigned to mark the primary stressed words. The statistical results showed that there was a variance depending on part of speech and more markedly the comparative rating scores of correct words were highly correlated to the learner’s English proficiency in any part of speech. In the acoustic experiments, pitch and intensity were measured. It was confirmed that (1) both F0 and dB carried the cue to perceive a stressed-word but they were not necessarily correlated, and (2) the relationship between F0 and dB might be compared only by relative movement. By further analyzing these acoustic data, prosodic combination of F0 and dB might be relevant to the correct ratios of part of speech.
Time-reversal communications in a hostile, reverberative environment
Authors: Candy James V. , Meyer Alan W. , Poggio Andrew J. , Guidry Brian L.
Published: October 2013

Time-reversal (T/R) communications is a new application area motivated by the recent advances in T/R theory. T/R receivers offer an interesting solution to the communications problem for a reverberant channel. This paper describes the performance of various realizations of the T/R receiver for an acoustic communications experiment in air. An experiment is developed to evaluate the performance of point-to-point T/R receivers designed to extract a transmitted information sequence propagating in a hostile, highly reverberant environment. It is demonstrated that T/R receivers are capable of extracting the transmitted coded sequence from noisy microphone sensor measurements with reasonable success. The processing required to validate these experimental results is discussed. These results are also compared with those produced by an equivalent linear equalizer or inverse filter, which provides the optimal solution when it incorporates all of the reverberations.
Deconvolutional beamforming for air and underwater acoustic sensor arrays
Authors: Edelson Geoffrey S. , Sullivan Shelby F. , Alsup James M. , Whitehouse Harper J.
Published: October 2013

Autonomous acoustic sensor arrays are often plagued with poor spatial resolution capabilities, especially at the lowest frequencies. Beamforming techniques that are data-adaptive can improve upon the resolution capability of conventional beamformers under certain conditions. An alternate nonadaptive technique that is simply implemented and that achieves sidelobe reduction while retaining or narrowing main lobe beamwidth is presented. The method for weight matrix construction is based on regularized, constrained deconvolution. These deconvolutional beamformer (DBF) beamspace weights, which are precomputed off-line using this nonlinear process, are applied to the data using a linear process. The physical array may be smaller when using the DBF since this beamformer simultaneously reduces the width of the main lobe at low frequencies while reducing the integrated sidelobe level. This is something even ‘‘optimal’’ beamformers have difficulty doing since the main lobe generally increases as the sidelobes are reduced. One additional DBF attribute, when compared to most traditional weighting functions, is its compatibility with nonuniformly spaced arrays, including the special case of receive elements that are known to be missing. The automated procedure for determining these beamspace weights is discussed and results are shown for both air and underwater acoustic array data.
A method for making acoustically bright intensity zone
Authors: Choi Joung-Woo , Kim Yang-Hann
Published: October 2013

Acoustic variables on a selected zone can be manipulated by controlling input signals of the fixed sound sources. In the previous work [J.-W. Choi and Y.-H. Kim, J. Acoust. Soc. Am. 111, 1695 (2002)], acoustic potential energy was controlled to make a bright and dark sound zone in space. Extending this work, this paper addresses a method to manipulate acoustic intensity in the zone of interest. This inevitably has to do with a magnitude as well as direction control, simply because intensity is a vector quantity. To accomplish this objective, it is required to define the acoustic intensity that can represent acoustic intensity distribution in the selected zone. This has been attempted by defining mean intensity projected to the desired direction. This mean intensity is maximized provided that the input power is kept constant. [Work supported by NRL project of KISTEP and the BK21 project initiated by the Ministry of Education and Human Resources Development of Korea.]
A speech enhancement method using the sliding DFT
Authors: Ono Hiroyuki , Murakami Takahiro , Ishida Yoshihisa
Published: October 2013

In this paper, we propose a novel noise reduction of speech signals using sliding DFT (SDFT) which is based on the spectral subtraction method. The spectral subtraction method reduces noise by subtracting the spectrum of noise estimated from an input signal and is a relatively simple and effective technique. We use SDFT to obtain the frequency spectra of speech signals. As is well known, to obtain the successive N-points output, SDFT requires only N times of complex multiplication, although the Fast Fourier Transform (FFT) requires Nlog2N times that. Thus SDFT is computationally simple as compared with FFT. The frame length, N, is determined based on the pitch period. In this paper, the pitch period is estimated by using an ideal low-pass filter and the analytic signal that is obtained from speech signals by the Hilbert converter. Finally, it is shown that the proposed method has good performance for speech enhancement.
Signal propagation and the dispersion relations of bubbly water
Authors: Orris Gregory J. , Nicholas Michael , Dacol Dalcio
Published: October 2013

The physics behind the extreme variations of the phase velocity of acoustic wave propagation in a bubbly liquid as a function of frequency have been addressed theoretically. Until recently there has not been a concerted experimental effort to validate this work over the rather large parameter landscape covered by the theories. To this end there there have been several sets of experiments conducted at the Naval Research Laboratory’s Salt-Water Tank Facility aimed in part at validating these theories. In order to properly measure phase velocities in a semi-free field environment, one must be able to accurately measure the arrival of a short acoustic pulse. This leads naturally to the question of what one measures as the velocity of sound in a highly dispersive medium where the group velocity can indeed have infinite, zero, or negative values. We discuss this and its relationship to work in other fields of physics. [Work supported by ONR.]
A method to prove violation of building code sound insulation standards in small condominiums
Authors: Lubman David
Published: October 2013

Building code sound insulation standards are health measures intended to protect people from excessive noise. In the USA, minimum values for Field Sound Transmission Loss (FSTC), and Field Impact Insulation Class (FIIC) are widely used to rate noise insulation between adjacent condominiums. Current American Society for Testing and Materials (ASTM) field test standards specify minimum room volumes for each of 16 one-third octave band test frequencies. For field impact insulation class ratings (FIIC), ASTM E 1007 specifies a minimum room volume of 2100 ft3 for valid measurement in the 100-Hz band. For air-borne sound transmission class ratings (FSTC), ASTM E 336 specifies minimum room volumes of 1400 ft3 for valid measurement in the 125-Hz band. FIIC and FSTC cannot be determined for bedrooms and kitchens of smaller condominiums which fail the minimum size requirement for the lowest bands. However, upper bounds can be determined merely by excluding invalid lower bands from computations. It is shown that when the upper bound on FIIC or FSTC falls below the code requirement (field values of 45 under the Uniform Building Code and the International Building Code), one may logically conclude that the code requirement is violated under existing standards.
Integrated acoustics systems for ocean observatories
Authors: Howe Bruce M. , Miller James H.
Published: October 2013

Integrated acoustics systems providing navigation and communications and conducting acoustic measurements in support of science applications is, in concept, analogous to the Global Positioning System, but relies on acoustics because the ocean is opaque to electromagnetic waves and transparent to sound. A series of nested systems is envisioned, from small- to regional- to basin-scale. A small number of acoustic sources sending coded, low power signals can service unlimited numbers of inexpensive receivers. Drifting floats with receivers can be tracked accurately while collecting ocean circulation and heat content data, as well as ambient sound data about wind, rain, marine mammals, and seismic activity. The sources can double as transmitters of control data from users to remote instruments; if enabled as receivers, two-way acoustic communications links in large-scale networks can be established. Acoustic-based instrumentation that shares the acoustic bandwidth with, and depends upon, the navigation and communications capabilities completes the concept of integrated acoustic systems.
A ‘‘Fresnel-transducer’’ for prostate hyperthermia treatment
Authors: Keolian Robert M. , Al-Bataineh Osama M. , Smith Nadine B. , Sparrow Victor W. , Harpster Lewis E.
Published: October 2013

Simulations and construction methods will be described for a novel ‘‘Fresnel-transducer.’’ The transducer is designed for transrectal hyperthermia treatment of prostate cancer as an adjuvant to radiotherapy or chemotherapy. Forty nine 6.3 mm diameter 1.5 MHz PZT elements are arranged in a 3 by 7 cm honeycomb-like pattern. They are individually aimed so that their beams partially converge behind the prostate. The increased beam density away from the transducer compensates for the loss of acoustic intensity due to attenuation. The aiming of the beams is additionally biased toward the periphery of the heated region to compensate for cooling from lateral heat conduction. The elements are divided into three interspersed sets, each driven at a slightly different frequency, to minimize stationary Moire interference bands between the beams. The combined effect is to uniformly raise the prostate temperature to 43°C without overheating the rectal wall. [Research supported by the Department of Defense Congressionally Directed Medical Prostate Cancer Research Program.]